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Rule

Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to the U.S. Navy Training and Testing Activities in the Hawaii-Southern California Training and Testing Study Area

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AGENCY:

National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce.

ACTION:

Final rule; notification of issuance of Letters of Authorization.

SUMMARY:

NMFS, upon request from the U.S. Navy (Navy) issues these regulations pursuant to the Marine Mammal Protection Act (MMPA) to govern the taking of marine mammals incidental to the training and testing activities conducted in the Hawaii-Southern California Training and Testing (HSTT) Study Area over the course of five years beginning in December 2018. These regulations, which allow for the issuance of Letters of Authorization (LOA) for the incidental take of marine mammals during the described activities and timeframes, prescribe the permissible methods of taking and other means of effecting the least practicable adverse impact on marine mammal species or stocks and their habitat, and establish requirements pertaining to the monitoring and reporting of such taking.

DATES:

Effective from December 21, 2018 through December 20, 2023.

ADDRESSES:

A copy of the Navy's application and supporting documents, as well as a list of the references cited in this document, may be obtained online at: www.fisheries.noaa.gov/​national/​marine-mammal-protection/​incidental-take-authorizations-military-readiness-activities. In case of problems accessing these documents, please call the contact listed below (see FOR FURTHER INFORMATION CONTACT).

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Stephanie Egger, Office of Protected Resources, National Marine Fisheries Service, 1315 East-West Highway, Silver Spring, MD 20910, (301) 427-8401.

End Further Info End Preamble Start Supplemental Information

SUPPLEMENTARY INFORMATION:

Purpose of Regulatory Action

These regulations, issued under the authority of the MMPA (16 U.S.C. 1361 et seq.), establish a framework for authorizing the take of marine mammals incidental to the Navy's training and testing activities (categorized as military readiness activities) from the use of sonar and other transducers, in-water detonations, air guns, impact pile driving/vibratory extraction, and potential vessel strikes based on Navy movement throughout the HSTT Study Area. The HSTT Study Area (see Figure 1.1-1 of the Navy's rulemaking/LOA application) is comprised of established operating and warning areas across the north-central Pacific Ocean, from the mean high tide line in Southern California west to Hawaii and the International Date Line. The Study Area includes the at-sea areas of three existing range complexes (the Hawaii Range Complex, the Southern California (SOCAL) Range Complex, and the Silver Strand Training Complex), and overlaps a portion of the Point Mugu Sea Range (PMSR). Also included in the Study Area are Navy pierside locations in Hawaii and Southern California, Pearl Harbor, San Diego Bay, and the transit corridor [1] on the high seas where sonar training and testing may occur.

We received an application from the Navy requesting five-year regulations and authorizations to incidentally take individuals of multiple species and stocks of marine mammals (“Navy's rulemaking/LOA application” or “Navy's application”). Take is anticipated to occur by Level A and Level B harassment as well as a very small number of serious injuries or mortalities incidental to the Navy's training and testing activities.

Section 101(a)(5)(A) of the MMPA (16 U.S.C. 1371(a)(5)(A)) directs the Secretary of Commerce (as delegated to NMFS) to allow, upon request, the incidental, but not intentional taking of small numbers of marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) within a specified geographical region if, after notice and public comment, the agency makes certain findings and issues regulations that set forth permissible methods of taking pursuant to that activity, as well as monitoring and reporting requirements. Section 101(a)(5)(A) of the MMPA and the implementing regulations at 50 CFR part 216, subpart I, provide the legal basis for issuing this final rule and the subsequent LOAs. As directed by this legal authority, this final rule contains mitigation, monitoring, and reporting requirements.

Summary of Major Provisions Within the Final Rule

Following is a summary of the major provisions of this final rule regarding the Navy's activities. Major provisions include, but are not limited to:

The use of defined powerdown and shutdown zones (based on activity);

Measures to reduce or eliminate the likelihood of ship strikes;

Activity limitations in certain areas and times that are biologically important (i.e., for foraging, migration, reproduction) for marine mammals;

Implementation of a Notification and Reporting Plan (for dead, live stranded, or marine mammals struck by a vessel); and

Implementation of a robust monitoring plan to improve our understanding of the environmental effects resulting from the Navy training and testing activities.

Additionally, the rule includes an adaptive management component that allows for timely modification of mitigation or monitoring measures based on new information, when appropriate.

Background

Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) direct the Secretary of Commerce (as delegated to NMFS) to allow, upon request, the incidental, but not intentional, taking of small numbers of marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) within a specified geographical region if certain findings are made and either regulations are issued or, if the taking is limited to harassment, a notice of a proposed authorization is provided to the public for review and the opportunity to submit comments.

An authorization for incidental takings shall be granted if NMFS finds that the taking will have a negligible impact on the species or stock(s), will not have an unmitigable adverse impact on the availability of the species or stock(s) for subsistence uses (where relevant), and if the permissible methods of taking, other means of effecting the least practicable adverse impact on the species or stocks and their habitat, and requirements pertaining to monitoring and reporting of such takings are set forth. The MMPA states that the term “take” means to harass, hunt, capture, kill or attempt to harass, hunt, capture, or kill any marine mammal.Start Printed Page 66847

The National Defense Authorization Act of 2004 (2004 NDAA) (Pub. L. 108-136) amended section 101(a)(5) of the MMPA to remove the “small numbers” and “specified geographical region” provisions indicated above for “military readiness activities” and amended the definition of “harassment” as it applies to military readiness activities, along with certain research activities. The definitions of all applicable MMPA statutory terms cited above are included in the relevant sections below.

More recently, the John S. McCain National Defense Authorization Act for Fiscal Year 2019 (2019 NDAA) (Pub. L. 115-232) amended the MMPA to allow incidental take rules for military readiness activities to be issued for up to seven years. That recent amendment of the MMPA does not affect this final rule, however, because both the Navy's application and NMFS' proposed incidental take rule preceded passage of the 2019 NDAA and contemplated authorization for five years.

Summary and Background of Request

On September 13, 2017, NMFS received an application from the Navy for authorization to take marine mammals by Level A and B harassment incidental to training and testing activities (categorized as military readiness activities) from the use of sonar and other transducers, in-water detonations, air guns, and impact pile driving/vibratory extraction in the HSTT Study Area. In addition, the Navy requested incidental take authorization by serious injury or mortality for a combined ten takes of two marine mammal species from explosives and for up to three takes of large whales from vessel strikes over the five-year period. On October 13, 2017, the Navy sent an amendment to its application and the application was found to be adequate and complete. On October 20, 2017 (82 FR 48801), we published a notice of receipt of application (NOR) in the Federal Register, requesting comments and information related to the Navy's request for 30 days. On June 26, 2018, we published a notice of the proposed rulemaking (83 FR 29872) and requested comments and information related to the Navy's request for 45 days. Comments received during the NOR and the proposed rulemaking comment periods are addressed in this final rule. See further details addressing comments received in the Comments and Responses section.

On September 10, 2018, and October 26, 2018, Navy provided NMFS with memoranda revising the estimated takes by serious injury or mortality included in the Navy's rulemaking/LOA application for ship strike. The Navy's request for takes by serious injury or mortality of three large whales over the course of five years remains unchanged. However, specifically, after further analysis and discussion with NMFS, the Navy modified their request for takes from particular stocks in the following ways:

  • Humpback whales (California, Oregon, Washington (CA/OR/WA) stock):

○ Reduced request for take from two to one individual.

○ Removed the authorization request for individuals that also are part of the Central America Distinct Population Segment (DPS) recognized under the Endangered Species Act (ESA). Both the Central America DPS and Mexico DPS overlap with the CA/OR/WA stock, but from this stock, only a humpback whale from the Mexico DPS is expected to be taken by serious injury or mortality. These individuals, that are part of both the CA/OR/WA stock and the Mexico DPS, will be referred to as “humpback whales (CA/OR/WA stock, Mexico DPS)” henceforth.

  • Sperm whale (Hawaii or CA/OR/WA stock):

○ Original authorization request for take was for two total from any stock; reduced request for take to one individual.

○ Removed request for individuals from the CA/OR/WA stock, i.e., only an individual from the Hawaii stock is requested.

  • Bryde's whale (Eastern Tropical Pacific stock or Hawaii stock)—Reduced request for take from one individual to zero.
  • Minke whale (Hawaii stock)—Reduced request for take from one individual to zero.
  • Sei whale (Hawaii stock and Eastern North Pacific stock)—Reduced request for take from one individual to zero.

NMFS concurs that it is reasonably likely that these lethal takes could occur. The information and assessment that supports this change is included in the Estimated Take of Marine Mammals section.

The Navy requested two five-year LOAs, one for training activities and one for testing activities to be conducted within the HSTT Study Area. The HSTT Study Area (see Figure 1.1-1 of the Navy's rulemaking/LOA application) is comprised of established operating and warning areas across the north-central Pacific Ocean, from the mean high tide line in Southern California west to Hawaii and the International Date Line. The Study Area includes the at-sea areas of three existing range complexes (the Hawaii Range Complex, the SOCAL Range Complex, and the Silver Strand Training Complex), and overlaps a portion of the PMSR. Also included in the Study Area are Navy pierside locations in Hawaii and Southern California, Pearl Harbor, San Diego Bay, and the transit corridor on the high seas where sonar training and testing may occur.

The following types of training and testing, which are classified as military readiness activities pursuant to the MMPA, as amended by the 2004 NDAA, would be covered under the regulations and associated LOAs: Amphibious warfare (in-water detonations), anti-submarine warfare (sonar and other transducers, in-water detonations), surface warfare (in-water detonations), mine warfare (sonar and other transducers, in-water detonations), and other warfare activities (sonar and other transducers, pile driving, air guns). Also, ship strike by Navy vessels is addressed and covered, as appropriate.

This will be NMFS' third in a series of rulemakings for testing and training activities in the HSTT Study Area. Hawaii and Southern California were separate in the initial rulemaking period, and the first two rules were effective from January 5, 2009, through January 5, 2014 (74 FR 1456; January 12, 2009), and January 14, 2009, through January 14, 2014 (74 FR 3882; January 21, 2009), respectively. The rulemaking for the second five-year period, which combined Hawaii and Southern California, was in effect from December 24, 2013, through December 24, 2018 (78 FR 78106; December 24, 2013), as modified by the terms of a stipulated settlement agreement and order issued by the United States District Court for the District of Hawaii on September 14, 2015. The new regulations described here will be valid for five years, from December 21, 2018, though December 20, 2023.

The Navy's mission is to organize, train, equip, and maintain combat-ready naval forces capable of winning wars, deterring aggression, and maintaining freedom of the seas. This mission is mandated by Federal law (10 U.S.C. 5062), which ensures the readiness of the naval forces of the United States. The Navy executes this responsibility by training and testing at sea, often in designated operating areas (OPAREA) and testing and training ranges. The Navy must be able to access and utilize these areas and associated sea space and air space in order to develop and maintain skills for conducting naval activities.

The Navy plans to conduct training and testing activities within the HSTT Study Area. The Navy has been conducting similar military readiness activities in the HSTT Study Area since the 1940s. The tempo and types of training and testing activities have fluctuated because of the introduction of new technologies, the evolving nature of international events, advances in warfighting doctrine and procedures, and changes in force structure Start Printed Page 66848(organization of ships, weapons, and personnel). Such developments influenced the frequency, duration, intensity, and location of required training and testing activities, but the basic nature of sonar and explosive events conducted in the HSTT Study Area has remained the same.

The Navy's rulemaking/LOA application reflects the most up to date compilation of training and testing activities deemed necessary to accomplish military readiness requirements. The types and numbers of activities included in the rule account for fluctuations in training and testing in order to meet evolving or emergent military readiness requirements.

These regulations cover training and testing activities that would occur for a five-year period following the expiration of the current MMPA authorization for the HSTT Study Area, which expires on December 24, 2018.

Description of the Specified Activity

Additional detail regarding the specified activity was provided in our Federal Register notice of proposed rulemaking (83 FR 29872; June 26, 2018); please see that notice of proposed rulemaking or the Navy's application for more information. Since the proposed rule, NMFS and the Navy have reached agreement on additional mitigation measures which are summarized below and discussed in greater detail in the Mitigation Measures section of this rule.

The Navy will implement pre- and post-event observation of the mitigation zone for all in-water explosive event mitigation measures in the HSTT Study Area. The Navy expanded their mitigation areas to include the sections of the Santa Monica Bay to Long Beach and San Nicolas Island biologically important areas (BIAs) that overlap the HSTT Study Area. These areas are referred to as the Santa Monica/Long Beach and San Nicolas Island Mitigation Areas and explosive use is limited in these areas as described in the Mitigation Measures section. Further, the Navy will limit surface ship sonar such that it will not exceed 200 hours from June through October cumulatively within the San Diego Arc, San Nicolas Island, and Santa Monica/Long Beach, Mitigation Areas. The Navy will also add a year-round limitation on explosives to the 4-Islands Region Mitigation Area, which includes a portion of the false killer whale (Main Hawaiian Island insular stock) BIA north of Maui and Molokai in the HSTT Study Area. The Navy has agreed to issue notification messages to increase operator awareness of the presence of marine mammals. The Navy will review WhaleWatch, a program coordinated by NMFS' West Coast Region as an additional information source to inform the drafting of the seasonal awareness message to alert vessels in the area to the possible presence of concentrations of large whales, including blue, gray, and fin whales in SOCAL.

In coordination with NMFS, the Navy has also revised its estimate of and request for serious injury or mortality takes of large whales from ship strikes, as described immediately above in the Summary and Background of Request section. The detailed rationale for this change is provided in the Estimated Take of Marine Mammals section.

Overview of Training and Testing Activities

The Navy routinely trains and tests in the HSTT Study Area in preparation for national defense missions. Training and testing activities covered in these regulations are summarized below.

Primary Mission Areas

The Navy categorizes its activities into functional warfare areas called primary mission areas. These activities generally fall into the following seven primary mission areas: Air warfare; amphibious warfare; anti-submarine warfare (ASW); electronic warfare; expeditionary warfare; mine warfare (MIW); and surface warfare (SUW). Most activities addressed in the HSTT FEIS/OEIS are categorized under one of the primary mission areas; the testing community has three additional categories of activities for vessel evaluation, unmanned systems, and acoustic and oceanographic science and technology. Activities that do not fall within one of these areas are listed as “other activities.” Each warfare community (surface, subsurface, aviation, and special warfare) may train in some or all of these primary mission areas. The testing community also categorizes most, but not all, of its testing activities under these primary mission areas.

The Navy describes and analyzes the impacts of its training and testing activities within the HSTT FEIS/OEIS and the Navy's rulemaking/LOA application (documents available at www.fisheries.noaa.gov/​national/​marine-mammal-protection/​incidental-take-authorizations-military-readiness-activities). In its assessment, the Navy concluded that sonar and other transducers, in-water detonations, air guns, and pile driving/removal were the stressors that would result in impacts on marine mammals that could rise to the level of harassment (and serious injury or mortality by explosives or by vessel strike) as defined under the MMPA. Therefore, the rulemaking/LOA application provides the Navy's assessment of potential effects from these stressors in terms of the various warfare mission areas in which they would be conducted. In terms of Navy's primary warfare areas, this includes:

Amphibious warfare (in-water detonations);

ASW (sonar and other transducers, in-water detonations);

SUW (in-water detonations);

MIW (sonar and other transducers, in-water detonations); and

Other warfare activities (sonar and other transducers, impact pile driving/vibratory removal, air guns).

Overview of Major Training Exercises and Other Exercises Within the HSTT Study Area

A major training exercise (MTE) is comprised of several “unit level” range exercises conducted by several units operating together while commanded and controlled by a single Commander. These exercises typically employ an exercise scenario developed to train and evaluate the strike group in naval tactical tasks. In an MTE, most of the activities being directed and coordinated by the Commander are identical in nature to the activities conducted during individual, crew, and smaller unit level training events. In an MTE, however, these disparate training tasks are conducted in concert, rather than in isolation.

Some integrated or coordinated ASW exercises are similar in that they are comprised of several unit level exercises but are generally on a smaller scale than an MTE, are shorter in duration, use fewer assets, and use fewer hours of hull-mounted sonar per exercise. For the purpose of analysis, three key factors are used to identify and group major, integrated, and coordinated exercises including the scale of the exercise, duration of the exercise, and amount of hull-mounted sonar hours modeled/used for the exercise. NMFS considered the effects of all training exercises, not just these major, integrated, and coordinated training exercises in these regulations. Additional detail regarding the training activities was provided in our Federal Register notice of proposed rulemaking (83 FR 29872; June 26, 2018); please see that notice of proposed rulemaking or the Navy's application for more information.

Overview of Testing Activities Within the HSTT Study Area

The Navy's research and acquisition community engages in a broad spectrum Start Printed Page 66849of testing activities in support of the fleet. These activities include, but are not limited to, basic and applied scientific research and technology development; testing, evaluation, and maintenance of systems (e.g., missiles, radar, and sonar) and platforms (e.g., surface ships, submarines, and aircraft); and acquisition of systems and platforms to support Navy missions and give a technological edge over adversaries. The individual commands within the research and acquisition community included in the Navy's rulemaking/LOA application are the Naval Air Systems Command, the Naval Sea Systems Command, the Office of Naval Research, and the Space and Naval Warfare Systems Command. Additional detail regarding the testing activities was provided in our Federal Register notice of proposed rulemaking (83 FR 29872; June 26, 2018); please see that notice of proposed rulemaking or the Navy's application for more information.

Dates and Duration

The specified activities may occur at any time during the five-year period of validity of the regulations. Planned number and duration of training and testing activities are shown in the Planned Activities section (Tables 4 through 7).

Specific Geographic Area

The Navy's HSTT Study Area extends from the north-central Pacific Ocean, from the mean high tide line in Southern California west to Hawaii and the International Date Line, including the Hawaii and Southern California (SOCAL) Range Complexes, as well as the Silver Strand Training Complex and overlapping a small portion of the Point Mugu Sea Range (PMSR). Please refer to Figure 1-1 of the Navy's rulemaking/LOA application for a map of the HSTT Study Area, Figures 2-1 to 2-4 for the Hawaii Operating Area (where the majority of training and testing activities occur within the Hawaii Range Complex), Figures 2-5 to 2-7 for the SOCAL Range Complex, and Figure 2-8 for the Silver Strand Training Complex.

Description of Acoustic and Explosive Stressors

The Navy uses a variety of sensors, platforms, weapons, and other devices, including ones used to ensure the safety of Sailors and Marines, to meet its mission. Training and testing with these systems may introduce acoustic (sound) energy or shock waves from explosives into the environment. The Navy's rulemaking/LOA application describes specific components that could act as stressors by having direct or indirect impacts on the environment. The following subsections describe the acoustic and explosive stressors for biological resources within the HSTT Study Area. Because of the complexity of analyzing sound propagation in the ocean environment, the Navy relies on acoustic models in its environmental analyses that consider sound source characteristics and varying ocean conditions across the HSTT Study Area. Stressor/resource interactions that were determined to have de minimus or no impacts (i.e., vessel, aircraft, or weapons noise) were not carried forward for analysis in the Navy's rulemaking/LOA application. NMFS reviewed the Navy's analysis and conclusions and finds them complete and supportable.

Acoustic Stressors

Acoustic stressors include acoustic signals emitted into the water for a specific purpose, such as sonar, other transducers (devices that convert energy from one form to another—in this case, to sound waves), and air guns, as well as incidental sources of broadband sound produced as a byproduct of impact pile driving and vibratory extraction. Explosives also produce broadband sound but are analyzed separately from other acoustic sources due to their unique characteristics. In order to better organize and facilitate the analysis of approximately 300 sources of underwater sound used for training and testing by the Navy, including sonars, other transducers, air guns, and explosives, a series of source classifications, or source bins, were developed. The source classification bins do not include the broadband sounds produced incidental to pile driving, vessel or aircraft transits, weapons firing, and bow shocks.

The use of source classification bins provides the following benefits: Provides the ability for new sensors or munitions to be covered under existing authorizations, as long as those sources fall within the parameters of a “bin;” improves efficiency of source utilization data collection and reporting requirements under the MMPA authorizations; ensures a conservative approach to all impact estimates, as all sources within a given class are modeled as the most impactful source (highest source level, longest duty cycle, or largest net explosive weight) within that bin; allows analyses to be conducted in a more efficient manner, without any compromise of analytical results; and provides a framework to support the reallocation of source usage (hours/explosives) between different source bins, as long as the total numbers of takes remain within the overall analyzed and authorized limits. This flexibility is required to support evolving Navy training and testing requirements, which are linked to real world events.

Sonar and Other Transducers

Active sonar and other transducers emit non-impulsive sound waves into the water to detect objects, safely navigate, and communicate. Passive sonars differ from active sound sources in that they do not emit acoustic signals; rather, they only receive acoustic information about the environment, or listen.

The Navy employs a variety of sonars and other transducers to obtain and transmit information about the undersea environment. Some examples are mid-frequency hull-mounted sonar used to find and track submarines; high-frequency small object detection sonars used to detect mines; high frequency underwater modems used to transfer data over short ranges; and extremely high-frequency (>200 kilohertz (kHz)). Doppler sonars used for navigation, like those used on commercial and private vessels. The characteristics of these sonars and other transducers, such as source level, beam width, directivity, and frequency, depend on the purpose of the source. Higher frequencies can carry more information or provide more information about objects off which they reflect, but attenuate more rapidly. Lower frequencies attenuate less rapidly, so may detect objects over a longer distance, but with less detail.

Additional detail regarding sound sources and platforms and categories of acoustic stressors was provided in our Federal Register notice of proposed rulemaking (83 FR 29872; June 26, 2018); please see that notice of proposed rulemaking or the Navy's application for more information.

Sonars and other transducers are grouped into classes that share an attribute, such as frequency range or purpose of use. Classes are further sorted by bins based on the frequency or bandwidth; source level; and, when warranted, the application in which the source would be used, as follows:

Frequency of the non-impulsive acoustic source;

○ Low-frequency sources operate below 1 kHz;

○ Mid-frequency sources operate at and above 1 kHz, up to and including 10 kHz;

○ High-frequency sources operate above 10 kHz, up to and including 100 kHz;

○ Very high-frequency sources operate above 100 kHz but below 200 kHz;

Sound pressure level (SPL) of the non-impulsive source;Start Printed Page 66850

○ Greater than 160 decibels (dB) re 1 micro Pascal (μPa), but less than 180 dB re 1 μPa;

○ Equal to 180 dB re 1 μPa and up to 200 dB re 1 μPa;

○ Greater than 200 dB re 1 μPa;

Application in which the source would be used;

○ Sources with similar functions that have similar characteristics, such as pulse length (duration of each pulse), beam pattern, and duty cycle.

The bins used for classifying active sonars and transducers that are quantitatively analyzed in the HSTT Study Area are shown in Table 1 below. While general parameters or source characteristics are shown in the table, actual source parameters are classified.

Table 1—Sonar and Transducers Quantitatively Analyzed in the HSTT Study Area

Source class categoryBinDescription
Low-Frequency (LF): Sources that produce signals less than 1 kHzLF3 LF4LF sources greater than 200 dB. LF sources equal to 180 dB and up to 200 dB.
LF5LF sources less than 180 dB.
LF6LF sources greater than 200 dB with long pulse lengths.
Mid-Frequency (MF): Tactical and non-tactical sources that produce signals between 1-10 kHzMF1Hull-mounted surface ship sonars (e.g., AN/SQS-53C and AN/SQS-60).
MF1KKingfisher mode associated with MF1 sonars.
MF2Hull-mounted surface ship sonars (e.g., AN/SQS-56).
MF3Hull-mounted submarine sonars (e.g., AN/BQQ-10).
MF4Helicopter-deployed dipping sonars (e.g., AN/AQS-13).
MF5Active acoustic sonobuoys (e.g., DICASS).
MF6Active underwater sound signal devices (e.g., MK84).
MF8Active sources (greater than 200 dB) not otherwise binned.
MF9Active sources (equal to 180 dB and up to 200 dB) not otherwise binned.
MF10Active sources (greater than 160 dB, but less than 180 dB) not otherwise binned.
MF11Hull-mounted surface ship sonars with an active duty cycle greater than 80%.
MF12Towed array surface ship sonars with an active duty cycle greater than 80%.
MF13MF sonar sources.
High-Frequency (HF): Tactical and non-tactical sources that produce signals between 10-100 kHzHF1 HF2Hull-mounted submarine sonars (e.g., AN/BQQ-10). HF Marine Mammal Monitoring System.
HF3Other hull-mounted submarine sonars (classified).
HF4Mine detection, classification, and neutralization sonar (e.g., AQS-20).
HF5Active sources (greater than 200 dB) not otherwise binned.
HF6Active sources (equal to 180 dB and up to 200 dB) not otherwise binned.
HF7Active sources (greater than 160 dB, but less than 180 dB) not otherwise binned.
HF8Hull-mounted surface ship sonars (e.g., AN/SQS-61).
Anti-Submarine Warfare (ASW): Tactical sources (e.g., active sonobuoys and acoustic counter-measures systems) used during ASW training and testing activitiesASW1 ASW2 ASW3MF systems operating above 200 dB. MF Multistatic Active Coherent sonobuoy (e.g., AN/SSQ-125). MF towed active acoustic countermeasure systems (e.g., AN/SLQ-25).
ASW4MF expendable active acoustic device countermeasures (e.g., MK 3).
ASW5MF sonobuoys with high duty cycles.
Torpedoes (TORP): Source classes associated with the active acoustic signals produced by torpedoesTORP1Lightweight torpedo (e.g., MK 46, MK 54, or Anti-Torpedo Torpedo).
TORP2Heavyweight torpedo (e.g., MK 48).
TORP3Heavyweight torpedo (e.g., MK 48).
Forward Looking Sonar (FLS): Forward or upward looking object avoidance sonars used for ship navigation and safetyFLS2HF sources with short pulse lengths, narrow beam widths, and focused beam patterns.
FLS3VHF sources with short pulse lengths, narrow beam widths, and focused beam patterns.
Acoustic Modems (M): Systems used to transmit data through the waterM3MF acoustic modems (greater than 190 dB).
Swimmer Detection Sonars (SD): Systems used to detect divers and submerged swimmersSD1-SD2HF and VHF sources with short pulse lengths, used for the detection of swimmers and other objects for the purpose of port security.
Synthetic Aperture Sonars (SAS): Sonars in which active acoustic signals are post-processed to form high-resolution images of the seafloorSAS1 SAS2 SAS3MF SAS systems. HF SAS systems. VHF SAS systems.
SAS4MF to HF broadband mine countermeasure sonar.
Broadband Sound Sources (BB): Sonar systems with large frequency spectra, used for various purposesBB4 BB7LF to MF oceanographic source. LF oceanographic source.
BB9MF optoacoustic source.
Notes: ASW: Antisubmarine Warfare; BB: Broadband Sound Sources; FLS: Forward Looking Sonar; HF: High-Frequency; LF: Low-Frequency; M: Acoustic Modems; MF: Mid-Frequency; SAS: Synthetic Aperture Sonars; SD: Swimmer Detection Sonars; TORP: Torpedoes; VHF: Very High-Frequency.
Start Printed Page 66851

Air Guns

Small air guns with capacities up to 60 cubic inches (in3) would be used during testing activities in various offshore areas of the Southern California Range Complex and in the Hawaii Range Complex. Generated impulses would have short durations, typically a few hundred milliseconds, with dominant frequencies below 1 kHz. The root mean square (SPL rms) and peak pressure (SPL peak) at a distance 1 meter (m) from the air gun would be approximately 215 dB re 1 μPa and 227 dB re 1 μPa, respectively, if operated at the full capacity of 60 in3.

Pile Driving/Extraction

Impact pile driving and vibratory pile removal would occur during construction of an Elevated Causeway System (ELCAS), a temporary pier that allows the offloading of ships in areas without a permanent port. The source levels of the noise produced by impact pile driving and vibratory pile removal from an actual ELCAS impact pile driving and vibratory removal are shown in Table 2.

Table 2—Elevated Causeway System Pile Driving and Removal Underwater Sound Levels in the HSTT Study Area

Pile size and typeMethodAverage sound levels at 10 m
24-in. Steel Pipe PileImpact 1192 dB re 1 µPa SPL rms, 182 dB re 1 µPa2 s SEL (single strike).
24-in. Steel Pipe PileVibratory 2146 dB re 1 µPa SPL rms, 145 dB re 1 µPa2 s SEL (per second of duration).
1 Illingworth and Rodkin (2016),2 Illingworth and Rodkin (2015).
Notes: in = inch, SEL = Sound Exposure Level, SPL = Sound Pressure Level, rms = root mean squared, dB re 1 µPa = decibels referenced to 1 micropascal.

The size of the pier and number of piles used in an ELCAS event is approximately 1,520 ft long, requiring 119 supporting piles. Construction of the ELCAS would involve intermittent impact pile driving over approximately 20 days. Crews work 24 hours (hrs) a day and would drive approximately 6 piles in that period. Each pile takes about 15 minutes to drive with time taken between piles to reposition the driver. When training events that use the ELCAS are complete, the structure would be removed using vibratory methods over approximately 10 days. Crews would remove about 12 piles per 24-hour period, each taking about 6 minutes to remove.

Explosive Stressors

This section describes the characteristics of explosions during naval training and testing. The activities analyzed in the Navy's rulemaking/LOA application that use explosives are described in Appendix A (Navy Activity Descriptions) of the HSTT FEIS/OEIS. Additional detail regarding explosive stressors was provided in our Federal Register notice of proposed rulemaking (83 FR 29872; June 26, 2018); please see that notice of proposed rulemaking or the Navy's application for more information.

Explosive detonations during training and testing activities are associated with high-explosive munitions, including, but not limited to, bombs, missiles, rockets, naval gun shells, torpedoes, mines, demolition charges, and explosive sonobuoys. Explosive detonations during training and testing involving the use of high-explosive munitions (including bombs, missiles, and naval gun shells) could occur in the air or at the water's surface. Explosive detonations associated with torpedoes and explosive sonobuoys would occur in the water column; mines and demolition charges would be detonated in the water column or on the ocean bottom. Most detonations would occur in waters greater than 200 ft in depth, and greater than 3 nautical miles (Nmi) from shore, although most mine warfare, demolition, and some testing detonations would occur in shallow water close to shore. Those that occur close to shore are typically conducted on designated ranges.

In order to better organize and facilitate the analysis of explosives used by the Navy during training and testing that could detonate in water or at the water surface, explosive classification bins were developed. Explosives detonated in water are binned by net explosive weight. The bins of explosives that are for use in the HSTT Study Area are shown in Table 3 below.

Table 3—Explosives Analyzed in the HSTT Study Area

BinNet explosive weight 1 (lb)Example explosive source
E10.1-0.25Medium-caliber projectile.
E2>0.25-0.5Medium-caliber projectile.
E3>0.5-2.5Large-caliber projectile.
E4>2.5-5Mine neutralization charge.
E5>5-105-inch projectile.
E6>10-20Hellfire missile.
E7>20-60Demo block/shaped charge.
E8>60-100Light-weight torpedo.
E9>100-250500 lb. bomb.
E10>250-500Harpoon missile.
E11>500-650650 lb. mine.
E12>650-1,0002,000 lb. bomb.
E13 2>1,000-1,740Multiple Mat Weave charges.
1 Net Explosive Weight refers to the equivalent amount of TNT.
2 E13 is not modeled for protected species impacts in water because most energy is lost into the air or to the bottom substrate due to detonation in very shallow water. In addition, activities are confined to small coves without regular marine mammal occurrence. These are not single charges, but multiple smaller charges detonated simultaneously or within a short time period.
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Explosive Fragments

Marine mammals could be exposed to fragments from underwater explosions associated with the specified activities. When explosive ordnance (e.g., bomb or missile) detonates, fragments of the weapon are thrown at high-velocity from the detonation point, which can injure or kill marine mammals if they are struck. These fragments may be of variable size and are ejected at supersonic speed from the detonation. The casing fragments will be ejected at velocities much greater than debris from any target due to the proximity of the casing to the explosive material. Risk of fragment injury reduces exponentially with distance as the fragment density is reduced. Fragments underwater tend to be larger than fragments produced by in-air explosions (Swisdak and Montaro, 1992). Underwater, the friction of the water would quickly slow these fragments to a point where they no longer pose a threat. In contrast, the blast wave from an explosive detonation moves efficiently through the seawater. Because the ranges to mortality and injury due to exposure to the blast wave far exceed the zone where fragments could injure or kill an animal, the thresholds are assumed to encompass risk due to fragmentation.

Other Stressor—Vessel Strike

Vessel strikes are not specific to any particular training or testing activity, but rather a potential, limited, sporadic, and incidental result of Navy vessel movement within the HSTT Study Area. Navy vessels transit at speeds that are optimal for fuel conservation or to meet training and testing requirements. Should a vessel strike occur, it would likely result in incidental take from serious injury and/or mortality and, accordingly, for the purposes of the analysis we assume that any authorized ship strike would result in serious injury or mortality. Information on Navy vessel movements is provided in the Planned Activities section. Additional detail on vessel strike was provided in our Federal Register notice of proposed rulemaking (83 FR 29872; June 26, 2018); please see that notice of proposed rulemaking or the Navy's application for more information. Additionally, as referenced above and described in more detail in the Estimated Take of Marine Mammals section, on September 10, 2018, and October 26, 2018, the Navy provided additional information withdrawing and reducing certain species from their request for serious injury or mortality takes from vessel strike with explanation supporting the Navy's change in requested take.

Planned Activities

Planned Training Activities

The training activities that the Navy plans to conduct in the HSTT Study Area are summarized in Table 4. The table is organized according to primary mission areas and includes the activity name, associated stressors applicable to these regulations, description of the activity, sound source bin, the number of planned activities, and the locations of those activities in the HSTT Study Area. For further information regarding the primary platform used (e.g., ship or aircraft type) see Appendix A (Navy Activity Descriptions) of the HSTT FEIS/OEIS.

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Planned Testing Activities

Testing activities covered in these regulations are described in Table 5 through Table 8.

Naval Air Systems Command

Table 5 summarizes the planned testing activities for the Naval Air Systems Command analyzed within the HSTT Study Area.

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Naval Sea Systems Command

Table 6 summarizes the planned testing activities for the Naval Sea Systems Command analyzed within the HSTT Study Area.

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Office of Naval Research

Table 7 summarizes the planned testing activities for the Office of Naval Research analyzed within the HSTT Study Area.

Space and Naval Warfare Systems Command

Table 8 summarizes the planned testing activities for the Space and Naval Warfare Systems Command analyzed within the HSTT Study Area.

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Summary of Acoustic and Explosive Sources Analyzed for Training and Testing

Table 9 through Table 12 show the acoustic source classes and numbers, explosive source bins and numbers, air gun sources, and pile driving and removal activities associated with Navy training and testing activities in the HSTT Study Area that were analyzed in this rule. Table 9 shows the acoustic source classes (i.e., LF, MF, and HF) that could occur in any year under the Planned Activities for training and testing activities. Under the Planned Activities, acoustic source class use would vary annually, consistent with the number of annual activities summarized above. The five-year total for the Planned Activities takes into account that annual variability.

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Table 10 shows the number of air gun shots planned in the HSTT Study Area for training and testing activities.

Table 10—Training and Testing Air Gun Sources Quantitatively Analyzed in the HSTT Study Area

Source class categoryBinUnit 1TrainingTesting
Annual5-Year totalAnnual5-Year total
Air Guns (AG): Small underwater air gunsAGC008444,220
1 C = count. One count (C) of AG is equivalent to 100 air gun firings.

Table 11 summarizes the impact pile driving and vibratory pile removal activities that would occur during a 24-hour period. Annually, for impact pile driving, the Navy will drive 119 piles, two times a year for a total of 238 piles. Over the five-year period of the rule, the Navy will drive a total of 1,190 piles by impact pile driving. Annually, for vibratory pile extraction, the Navy will extract 119 piles, two times a year for a total of 238 piles. Over the five-year period of the rule, the Navy will extract a total of 1,190 piles by vibratory pile extraction.

Table 11—Summary of Pile Driving and Removal Activities per 24-Hour Period in the HSTT Study Area

MethodPiles per 24-hour periodTime per pile minutesTotal estimated time of noise per 24-hour period minutes
Pile Driving (Impact)61590
Pile Removal (Vibratory)12672
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Table 12 shows the number of in-water explosives that could be used in any year under the Planned Activities for training and testing activities. Under the Planned Activities, bin use would vary annually, consistent with the number of annual activities summarized above. The five-year total for the Planned Activities takes into account that annual variability.

Vessel Movement

Vessels used as part of the Planned Activities include ships, submarines, unmanned vessels, and boats ranging in size from small, 22 ft (7 m) rigid hull inflatable boats to aircraft carriers with lengths up to 1,092 ft (333 m). The average speed of large Navy ships ranges between 10 and 15 knots and submarines generally operate at speeds in the range of 8-13 knots, while a few specialized vessels can travel at faster speeds. Small craft (for purposes of this analysis, less than 18 m in length) have much more variable speeds (0-50+ knots (kn), dependent on the activity), but generally range from 10 to 14 kn. From unpublished Navy data, average median speed for large Navy ships in the HSTT Study Area from 2011-2015 varied from 5-10 kn with variations by ship class and location (i.e., slower Start Printed Page 66872speeds close to the coast). While these speeds for large and small craft are representative of most events, some vessels need to temporarily operate outside of these parameters.

The number of Navy vessels used in the HSTT Study Area varies based on military training and testing requirements, deployment schedules, annual budgets, and other dynamic factors. Most training and testing activities involve the use of vessels. These activities could be widely dispersed throughout the HSTT Study Area, but would be typically conducted near naval ports, piers, and range areas. Navy vessel traffic would especially be concentrated near San Diego, California and Pearl Harbor, Hawaii. There is no seasonal differentiation in Navy vessel use because of continual operational requirements from Combatant Commanders. The majority of large vessel traffic occurs between the installations and the OPAREAs. Support craft would be more concentrated in the coastal waters in the areas of naval installations, ports, and ranges. Activities involving vessel movements occur intermittently and are variable in duration, ranging from a few hours up to weeks.

Standard Operating Procedures

For training and testing to be effective, personnel must be able to safely use their sensors and weapon systems as they are intended to be used in a real-world situation and to their optimum capabilities. While standard operating procedures are designed for the safety of personnel and equipment and to ensure the success of training and testing activities, their implementation often yields additional benefits to environmental, socioeconomic, public health and safety, and cultural resources.

Because standard operating procedures are essential to safety and mission success, the Navy considers them to be part of the planned activities, and has included them in the environmental analysis. Additional details on standard operating procedures were provided in our Federal Register notice of proposed rulemaking (83 FR 29872; June 26, 2018); please see that notice of proposed rulemaking or the Navy's application for more information.

Duration and Location

Training and testing activities would be conducted under this authorization in the HSTT Study Area throughout the years. The HSTT Study Area (see Figure 1.1-1 of the Navy's rulemaking/LOA application) is comprised of established operating and warning areas across the north-central Pacific Ocean, from the mean high tide line in Southern California west to Hawaii and the International Date Line. The Study Area includes the at-sea areas of three existing range complexes (the Hawaii Range Complex, the SOCAL Range Complex, and the Silver Strand Training Complex), and overlaps a portion of the PMSR. Also included in the Study Area are Navy pierside locations in Hawaii and Southern California, Pearl Harbor, San Diego Bay, and the transit corridor [2] on the high seas where sonar training and testing may occur.

A Navy range complex consists of geographic areas that encompass a water component (above and below the surface) and airspace, and may encompass a land component where training and testing of military platforms, tactics, munitions, explosives, and electronic warfare systems occur. Range complexes include OPAREAs and special use airspace, which may be further divided to provide better control of the area and events being conducted for safety reasons. Please refer to the regional maps provided in the Navy's rulemaking/LOA application (Figures 2-1 through 2-8) for additional detail of the range complexes and testing ranges. Additional detail on range complexes and testing ranges was provided in our Federal Register notice of proposed rulemaking (83 FR 29872; June 26, 2018); please see that notice of proposed rulemaking or the Navy's application for more information.

Comments and Responses

We published a notice of proposed regulations in the Federal Register on June 26, 2018 (83 FR 29872), with a 45-day comment period. In that notice of proposed rulemaking, we requested public input on the requests for authorization described therein, our analyses, and the proposed authorizations, and requested that interested persons submit relevant information, suggestions, and comments. During the 45-day comment period, we received 22 comment letters in total. Of this total, two submissions were from other Federal agencies, two letters were from organizations or individuals acting in an official capacity (e.g., non-governmental organizations (NGOs)) and 18 submissions were from private citizens. NMFS has reviewed all public comments received on the proposed rule and issuance of the LOAs. All relevant comments and our responses are described below. We provide no response to specific comments that addressed species or statutes not relevant to our proposed actions under section 101(a)(5)(A) of the MMPA (e.g., comments related to sea turtles). We organize our comment responses by major categories.

General Comments

The majority of the 18 comment letters from private citizens expressed general opposition toward the Navy's proposed training and testing activities and requested that NMFS not issue the LOAs, but without providing information relevant to NMFS' decisions. These comments appear to indicate a lack of understanding of the MMPA's requirement that NMFS “shall issue” requested authorizations when certain findings (see the Background section) can be made; therefore, these comments were not considered further. The remaining comments are addressed below.

Impact Analysis

General

Comment 1: A commenter recommended that the Navy provide NMFS with an acoustics analysis that addresses noise impacts on land, from the air, and underwater. Full environmental analysis of the noise would examine a suite of metrics appropriate to the array of resources impacted. The impacts should discuss potential effects on wildlife, visitors, and other noise-sensitive receivers.

The commenter also recommended that the Navy consider the following as it plans to conduct activities in the HSTT Study Area:

  • Use appropriate metrics to assess potential environmental impacts on land and water.
  • Determine natural ambient acoustic conditions as a baseline for analysis.
  • Assess effects from cumulative noise output, incorporating noise generated from other anthropogenic sources.
  • Determine distance at which noise will attenuate to natural levels.
  • Assess effects that these noise levels would have on terrestrial wildlife, marine wildlife, and visitors.
  • Appropriate and effective mitigation measures should be developed and used to reduce vessel strike (e.g., timing activities to avoid migration, and searching for marine Start Printed Page 66873mammals before and during activities and taking avoidance measures).

Response: NMFS refers the commenter to the HSTT FEIS/OEIS which conducts an assessment of all of the activities which comprise the proposed action and their impacts (including cumulative impacts) to relevant resources. The Navy is not required to do ambient noise monitoring or assess impacts to wildlife other than marine mammals or to visitors/tourists. The mitigation measures in the rule include procedural measures to minimize strike (avoiding whales by 500 yards, etc.), mitigation areas to minimize strike in biologically important areas, and Awareness Notification Message areas wherein all vessels are alerted to stay vigilant to the presence of large whales.

Density Estimates

Comment 2. A commenter commented that 30 iterations or Monte Carlo simulations is low for general bootstrapping methods used in those models but understands that increasing the number of iterations in turn increases the computational time needed to run the models. Accordingly, the commenter suggested that the Navy consider increasing the iterations from 30 to at least 200 for activities that have yet to be modeled for upcoming MMPA rulemakings for Navy testing and training activities.

Response: In areas where there are four season, 30 iterations are used in NAEMO which results in a total of 120 iterations per year for each event. However, in areas where only two seasons, warm and cold, the number of iterations per season is increased to 60 so that 120 iterations per year are maintained. Navy reached this number of iterations by running two iterations of a scenario and calculating the mean of exposures, then running a third iteration and calculating the running mean of exposures, then a fourth iteration and so on. This is done until the running mean becomes stable. Through this approach, it was determined 120 iterations was sufficient to converge to a statistically valid answer and provides a reasonable uniformity of exposure predictions for most species and areas. There are a few exceptions for species with sparsely populated distributions or highly variable distributions. In these cases, the running mean may not flatten out (or become stable); however, there were so few exposures in these cases that while the mean may fluctuate, the overall number of exposures did not result in significant differences in the totals. In total, the number of simulations conducted for HSTT Phase III exceeded six million simulations and produced hundreds of terabytes of data. Increasing the number of iterations, based on the discussion above, would not result in a significant change in the results, but would incur a significant increase in resources (e.g., computational and storage requirements). This would divert these resources from conducting other more consequential analysis without providing for meaningfully improved data. The Navy has communicated that it is continually looking at ways to improve NAEMO and reduce data and computational requirements. As technologies and computational efficiencies improve, Navy will evaluate these advances and incorporate them where appropriate. NMFS has reviewed the Navy's approach and concurs that it is technically sound and reflects the best available science.

Comment 3: A commenter had concerns regarding the Navy's pinniped density estimates. Given that a single density was provided for the respective areas and pinnipeds were assumed to occur at sea as individual animals, uncertainty does not appear to have been incorporated in the Navy's animat modeling for pinnipeds. The Navy primarily used sightings or abundance data, assuming certain correction factors, divided by an area to estimate pinniped densities. Many, if not all, of the abundance estimates had associated measures of uncertainty (i.e., coefficients of variation (CV), standard deviation (SD), or standard error (SE)). Therefore, the commenter recommended that NMFS require the Navy to specify whether and how it incorporated uncertainty in the pinniped density estimates into its animat modeling and if it did not, require the Navy to use measures of uncertainty inherent in the abundance data (i.e., CV, SD, SE) similar to the methods used for cetaceans.

Response: As noted in the cited technical report Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing (U.S. Department of the Navy, 2017a), the Navy did not apply statistical uncertainty outside the survey boundaries into non-surveyed areas, since it deemed application of statistical uncertainty would not be meaningful or appropriate. We note that there are no measures of uncertainty (i.e., no CV, SD, or SE) provided in NMFS Pacific Stock Assessment Report (SAR) Appendix 3 (Carretta et al., 2017) associated with the abundance data for any of the pinniped species present in Southern California or for monk seals in Hawaii. Although some measures of uncertainty are presented in some citations within the SAR and in other relevant publications for some survey findings, it is not appropriate for the Navy to attempt to derive summations of total uncertainty for an abundance when the authors of the cited studies and the SAR have not. For additional information regarding use of pinniped density data, see the cited U.S. Navy Marine Species Density Database Phase III for the Hawaii-Southern California Training and Testing Study Area Section 11 (U.S. Department of the Navy, 2017b). As a result of the lack of published applicable measures of uncertainty for pinnipeds, the Navy did not incorporate measures of uncertainty into the pinniped density estimates. NMFS independently reviewed the methods and densities used by the Navy and concur that they are appropriate and reflect the best available science.

Comment 4: A commenter had concerns regarding the various areas, abundance estimates, and correction factors that the Navy used for pinnipeds. The commenter referenced a lot of information in the context of both what the Navy used and what they could have used instead and summarizes the discussion with seven recommendations.

For harbor seals, the area was based on the NMFS SOCAL stratum (extending to the extent of the U.S. exclusive economic zone (EEZ), 370 km from the coast) for its vessel-based surveys (i.e., Barlow 2010) and the Navy applied the density estimates from the coast to 80-km offshore. The commenter believes that this approach is inappropriate and that the Navy should use the area of occurrence to estimate the densities for harbor seals. For harbor seals, the Navy assumed that 22 percent of the stock occurred in SOCAL, citing Department of the Navy (2015). The commenter had two concerns with this approach. First, one has to go to Department of the Navy (2015) to determine the original source of the information (Lowry et al., 2008; see the commenter's February 20, 2014, letter on this matter). Second, Lowry et al. (2008) indicated that 23.3 percent of the harbor seal population occurred in SOCAL, not 22 percent as used by the Navy. Therefore, the commenter recommended that, at the very least, NMFS require the Navy to revise the pinniped density estimates using the extent of the coastal range (e.g., from shore to 80 km offshore) of harbor seals as the applicable area, 23.3 percent of the California abundance estimate based on Lowry et al. (2008), and an at-sea correction factor of 65 percent based on Start Printed Page 66874Harvey and Goley (2011) for both seasons.

For Monk seals the area was based on the areas within the 200-m isobaths in both the Main and Northwest Hawaiian Islands (MHI and NWHI, respectively) and areas beyond the 200-m isobaths in the U.S. EEZ. The commenter asserted that some of the abundances used were not based on best available science. The Navy noted that its monk seal abundance was less than that reported by Baker et al. (2016), but that those more recent data were not available when the Navy's modeling process began. The Baker et al. (2016) data have been available for almost two years and should have been incorporated accordingly, particularly since the data would yield greater densities and the species is endangered. For monk seals, the commenter recommended using the 2015 monk seal abundance estimate from Baker et al. (2016) and an at-sea correction factor of 63 percent for the MHI based on Baker et al. (2016) and 69 percent for the NWHI based on Harting et al. (2017).

For the northern fur seals, the area was based on the NMFS SOCAL stratum (extending to the extent of the U.S. EEZ, 370 km from the coast) for its vessel-based surveys (i.e., Barlow 2010). For elephant seals, California sea lions, and Guadalupe fur seals, the area was based on the Navy SOCAL modeling area. The commenter had concerns that these areas are not based on the biology or ecology of these species. The commenter recommended using the same representative area for elephant seals, northern fur seals, Guadalupe fur seals, and California sea lions. The commenter recommended using an increasing trend of 3.8 percent annually for the last 15 years for elephant seals as part of the California population and at least 31,000 as representative of the Mexico population based on Lowry et al. (2014). Additionally, the commenter recommended using an at-sea correction factor of 44 percent for the cold season and 48 percent for the warm season for California sea lions based on Lowry and Forney (2005).

Finally, the commenter recommended that NMFS require the Navy to (1) specify the assumptions made and the underlying data that were used for the at-sea correction factors for Guadalupe and northern fur seals and (2) consult with experts in academia and at the NMFS Science Centers to develop more refined pinniped density estimates that account for pinniped movements, distribution, at-sea correction factors, and density gradients associated with proximity to haul-out sites or rookeries.

Response: The Navy provided additional clarification regarding the referenced concerns about areas, abundance estimates, and correction factors that were used for pinnipeds. We note that take estimation is not an exact science. There are many inputs that go into an estimate of marine mammal exposure, and the data upon which those inputs are based come with varying levels of uncertainty and precision. Also, differences in life histories, behaviors, and distributions of stocks can support different decisions regarding methods in different situations. Different methods may be supportable in different situations, and, further, there may be more than one acceptable method to estimate take in a particular situation. Accordingly, while NMFS always ensures that the methods are technically supportable and reflect the best available science, NMFS does not prescribe any one method for estimating take (or calculating some of the specific take estimate components that the commenter is concerned about). NMFS reviewed the areas, abundances, and correction factors used by the Navy to estimate take and concurs that they are appropriate. We note the following in further support of the analysis: While some of the suggestions the commenter makes could provide alternate valid ways to conduct the analyses, these modifications are not required in order to have equally valid and supportable analyses and, further, would not change NMFS' determinations for pinnipeds. In addition, we note that (1) many of the specific recommendations that the commenter makes are largely minor in nature: “44 not 47 percent,” “63 not 61 percent,” “23.3 not 22 percent” or “area being approximately 13 percent larger;” and (2) even where the recommendation is somewhat larger in scale, given the ranges of these stocks, the size of the stocks, and the number and nature of pinniped takes, recalculating the estimated take for any of these pinniped stocks using the commenter's recommended changes would not change NMFS' assessment of impacts on the recruitment or survival of any of these stocks, or the negligible impact determination. Below, we address the Commenters issues in more detail and, while we do not explicitly note it in every section, NMFS has reviewed the Navy's analysis and choices in relation to these comments and concurs that they are technically sound and reflect the best available science.

For harbor seals—Based on the results from satellite tracking of harbor seals at Monterey, California and the documented dive depths (Eguchi and Harvey, 2005), the extent of the range for harbor seals in the HSTT Study Area used by the Navy (a 50 nmi buffer around all known haul-out sites; approximately 93 km) is more appropriate than the suggested 80 km offshore suggested by commenter.

The comment is incorrect in its claim that the Navy did not use the best available science. Regarding the appropriate percentage of the California Current Ecosystem abundance to assign to the HSTT Study Area, the 22 percent that the Navy used is based on the most recent of the two years provided in Lowry et al. (2008) rather than the mean of two years, which is one valid approach. Additionally, since approximately 74 percent of the harbor seal population in the Channel Islands (Lowry et al., 2017) is present outside and to the north of the HSTT Study Area, it is a reasonable assumption that the 22 percent used already provides a conservative overestimate and that it would not be appropriate to apply a higher percentage of the overall population for distribution into the Navy's modeling areas.

Again the comment is incorrect in its claim that the correction factors applied to population estimates were either unsubstantiated or incorrect. Regarding the commenter's recommended use of an at-sea correction factor of 65 percent for both seasons based on Harvey and Goley (2011), that correction factor was specifically meant to apply to the single molting season when harbor seals are traditionally surveyed (see discussion in Lowry et al., 2017). Additionally, the authors of that study provided a correction factor (CF = 2.86; 35 percent) for Southern California but left open the appropriateness of that factor given the limited data available at the time. For these reasons, having separate correction factors for each of the seasons is more appropriate as detailed in Section 11.1.5 (Phoca vitulina, Pacific harbor seal) of the U.S. Navy Marine Species Density Database Phase III for the Hawaii-Southern California Training and Testing Study Area (U.S. Department of the Navy, 2017b).

For monk seals, as detailed in Section 11.1.4 (Neomonachus schauinslandi, Hawaiian monk seal) of the U.S. Navy Marine Species Density Database Phase III for the Hawaii-Southern California Training and Testing Study Area (U.S. Department of the Navy, 2017b), the Navy consulted with the researchers and subject matter experts at the Pacific Science Center and the Monk Seal Recovery Team regarding the abundance estimates, at sea correction factors, and distribution for monk seals in the Hawaiian Islands during development Start Printed Page 66875of the HSTT FEIS/OEIS throughout 2015 and the Summer of 2016. The Navy incorporated the results of those consultations, including unpublished data, into the analysis of monk seals. Additional details in this regard to monk seal distributions and population trends as reflected by the abundance in the Hawaiian Islands are presented in the FEIS/OEIS in Section 3.7.2.2.9.2 (Habitat and Geographic Range) and Section 3.7.2.2.9.3 (Population Trends). The Navy has indicated that it has continued ongoing communications with researchers at the Pacific Islands Science Center and elsewhere, has accounted for the findings in the citations noted by the commenter (Baker et al., 2016; Harting et al., 2017) as well as information in forthcoming publications provided ahead of publication via those researchers (cited as in preparation), and specifically asked for and received concurrence from subject matter experts regarding specific findings presented in the HSTT FEIS/OEIS regarding monk seals. The Navy also considered (subsequent to publication of the HSTT FEIS) the new Main Hawaiian Islands haulout correction factor presented in the publication by Wilson et al. (2017, which would be inconsistent with the use of the Baker et al. (2016) correction factors suggested by the commenter), and the Harting et al. (2017) correction factor, and has considered the new abundance numbers presented in the 2016 Stock Assessment Report, which first became available in January 2018. It is the Navy's assessment that a revision of the monk seal at-sea density would only result in small changes to the predicted effects and certainly would not change the conclusions presented in the HSTT FEIS/OEIS regarding impact on the population or the impact on the species. The Navy has communicated that it assumes that as part of the ongoing regulatory discussions with NMFS, changes to estimates of effects can be best dealt with in the next rulemaking given Wilson et al. (2017) has now also provided a totally new haulout correction factor for the Main Hawaiian Islands that was not considered in Baker et a l. (2016), Harting et al. (2017), or the 2016 SAR.

For northern fur seals, elephant seals, California sea lions, and Guadalupe fur seals, the Navy consulted with various subject matter experts regarding the abundances and distributions used in the HSTT FEIS/OEIS analyses for these species and based on those consultations and the literature available, the Navy and NMFS believe that the findings presented in the HSTT FEIS/OEIS and supporting technical reports provide the most accurate assessments available for these species. Given the demonstrated differences in the at-sea distributions of elephant seals, northern fur seals, Guadalupe fur seals, and California sea lions (Gearin et al., 2017; Lowry et al., 2014; Lowry,et al., 2017; Norris, 2017; Norris,et al., 2015; Robinson et al., 2012; University of California Santa Cruz and National Marine Fisheries Service, 2016), it would not be appropriate to use the same representative area for distributions of these species' population abundances. For example, California sea lions forage predominantly within 20 nautical miles from shore (Lowry and Forney, 2005), while tag data shows that many elephant seals (Robinson et al., 2012) and Guadalupe fur seals (Norris, 2017) seasonally forage in deep waters of the Pacific well outside the boundaries of the HSTT Study Area.

For northern elephant seals (Mirounga angustirostris, Northern elephant seal), as detailed in Section 11.1.3 of the technical report titled U.S. Navy Marine Species Density Database Phase III for the Hawaii-Southern California Training and Testing Study Area (U.S. Department of the Navy, 2017e), hereafter referred to as the Density Technical Report, the Navy considered a number of factors in the development of the data for this species, including the fact that not all of the elephant seal population is likely to occur exclusively within the Southern California portion of the HSTT Study Area. Given that the three main rookeries considered in this analysis are located at the northern boundary of the HSTT Study Area and that elephant seals migrate northward after the breeding season, the Navy, in consultation with subject matter experts, believes the current abundance used in the analysis is based on the best available science and represents a conservative overestimate of the number of elephant seals likely to be affected by Navy activities in the HSTT Study Area.

For California sea lions, the citation (Lowry and Forney, 2005) used as the basis for this recommendation specifically addressed the use of the Central and Northern California at-sea correction factor elsewhere, with the authors stating; “In particular, [use of the Central and Northern California at-sea correction factor] would not be appropriate for regions where sea lions reproduce, such as in the Southern California Bight (SCB) and in Mexico, . . .” Given the waters of the Southern California Bight and off Mexico overlap the HSTT Study Area and since the authors of the cited study specifically recommended not using the correction factor in the manner the commenter suggested, the Navy does not believe use of that correction factor for the HSTT Study Area would be appropriate. NMFS concurs with this approach

For Guadalupe fur seal—Additional detail regarding the data used for the analysis of Guadalupe fur seals has been added to the HSTT Final EIS/OEIS Section 3.7.2.2.8 (Arctocephalus townsendi, Guadalupe Fur Seal). The Navy had integrated the latest (September 2017) unpublished data for Guadalupe fur seals from researchers in the United States and Mexico into the at-sea correction factor and density distribution of the species used in the modeling, but consultations with experts in academia and at the NMFS Science Centers and their recommendations had not been finalized before release of the Draft EIS/OEIS. Subsequently, the Navy did not consider this revision of the text critical for the final NEPA document since the new data did not provide any significant change to the conclusions reached regarding the Guadalupe fur seal population. In fact, the data indicates an increase in the population and expansion of their range concurrent with decades of ongoing Navy training and testing in the SOCAL range complex.

For Northern Fur Seal—As presented in Section 11.1.2 (Callorhinus ursinus, Northern fur seal) of the Navy's Density Technical Report (U.S. Department of the Navy, 2017b), the correction factor percentages for northern fur seals potentially at sea were derived from the published literature as cited (Antonelis, Stewart, & Perryman, 1990; Ream, Sterling, & Loughlin, 2005; Roppel, 1984).

For future EISs, the Navy explained that it did and will continue to consult with authors of the papers relevant to the analyses as well as other experts in academia and at the NMFS Science Centers during the development of the Navy's analyses. During the development of the HSTT EIS/OEIS and as late as September 2017, the Navy had ongoing communications with various subject matter experts and specifically discussed pinniped movements, the distribution of populations within the study area to support the analyses, the pinniped haulout or at-sea correction factors, and the appropriateness of density gradients associated with proximity to haul-out sites or rookeries. As shown in the references cited, the personal communications with researchers have been made part of the public record, although many other Start Printed Page 66876informal discussions with colleagues have also assisted in the Navy's approach to the analyses presented.

The Navy acknowledges that there have been previous comments provided by this commenter on other Navy range complex documents regarding the use of satellite tag movement and location data to derive at-sea pinniped density data, and the Navy asserts that previous responses to those comments remain valid. Additionally, the commenter has noted that the “. . . Commenter continues to believe that data regarding movements and dispersion of tagged pinnipeds could yield better approximations of densities than the methods the Navy currently uses.” The Navy acknowledges that in comments to previous Navy EIS/OEIS analyses, the commenter has recommended this untried approach; responses to those previous comments have been provided. The Navy also notes that there have been papers suggesting the future application of Bayesian or Markov chain techniques for use in habitat modeling (e.g., Redfern et al., 2006) and overcoming the bias introduced by interpretation of population habitat use based on non-randomized tagging locations (e.g., Whitehead & Jonsen, 2013). However, the use of satellite tag location data in a Bayesian approach to derive cetacean or pinniped densities at sea has yet to be accepted, implemented, or even introduced in the scientific literature.

This issue was in fact recently discussed as part of the Density Modeling Workshop associated with the October 2017 Society for Marine Mammalogy conference. The consensus of the marine mammal scientists present was that while pinniped tag data could provide a good test case, it realistically was unlikely to be a focus of the near-term research. The working group determined that a focused technical group should be established to specifically discuss pinnipeds and data available for density surface modelling in the future. It was also discussed at the Density Modeling Workshop in October 2018. The Navy has convened a pinniped working group and NMFS ASFSC is sponsoring a demonstration project to use haulout and telemetry data from seals in Alaska to determine the viability of such an approach.

Therefore, consistent with previous assessments and based on recent discussions with subject matter experts in academia, the NMFS Science Centers, and the National Marine Mammal Laboratory, and given there is no currently established methodology for implementing the approach suggested by the commenter, the Navy believes that attempting to create and apply a new density derivation method at this point would introduce additional levels of uncertainty into density estimations.

For these reasons, the Navy and NMFS will not provide density estimates based on pinniped tracking data. Publications reporting on satellite tag location data have been and will continue to be used to aid in the understanding of pinniped distributions and density calculations as referenced in the FEIS/OEIS and the U.S. Navy Marine Species Density Database Phase III for the Hawaii-Southern California Training and Testing Study Area (U.S. Department of the Navy, 2017b). The Navy has communicated that it will continue, as it has in the past, to refine pinniped density and distributions using telemetry data and evolving new techniques (such as passive acoustic survey data) in development of the Navy's analyses. As noted above, NMFS has reviewed the Navy's methods and concurs that they are appropriate and reflect the best available science.

Comment 5: A commenter recommended that NMFS require the Navy to (1) specify what modeling method and underlying assumptions, including any relevant source spectra and assumed animal swim speeds and turnover rates, were used to estimate the ranges to PTS and TTS for impact and vibratory pile-driving activities, (2) accumulate the energy for the entire day of proposed activities to determine the ranges to PTS and TTS for impact and vibratory pile-driving activities, and (3) clarify why the PTS and TTS ranges were estimated to be the same for LF and HF cetaceans during impact pile driving.

Response: As explained in Section 3.7.3.1.4.1 of the HSTT FEIS/OEIS, the Navy measured values for source levels and transmission loss from pile driving of the Elevated Causeway System, the only pile driving activity included in the Specified Activity. The Navy reviewed the source levels and how the spectrum was used to calculate the range to effects; NMFS supports the use of these measured values. These recorded source waveforms were weighted using the auditory weighting functions. Low-frequency and high-frequency cetaceans have similar ranges for impact pile driving since low-frequency cetaceans would be relatively more sensitive to the low-frequency sound which is below high-frequency cetaceans' best range of hearing. Neither the NMFS user spreadsheet nor NAEMO were required for calculations. An area density model was developed in MS Excel which calculated zones of influence (ZOI) to thresholds of interest (e.g., behavioral response) based on durations of pile driving and the aforementioned measured and weighted source level values. The resulting area was then multiplied by density of each marine mammal species that could occur within the vicinity. This produced an estimated number of animals that could be impacted per pile, per day, and overall during the entire activity for both the impact pile driving and vibratory removal phases. NOAA HQ scientists involved in the acoustic criteria development reviewed the manner in which the Navy applied the frequency weighting and calculated all values and concurred with the approach.

Regarding the appropriateness of accumulating energy for the entire day, based on the best available science regarding animal reaction to sound, selecting a reasonable SEL calculation period is necessary to more accurately reflect the time period an animal would likely be exposed to the sound. The Navy factored both mitigation effectiveness and animal avoidance of higher sound levels into the impact pile driving analysis. For impact pile driving, the mitigation zone extends beyond the average ranges to PTS for all hearing groups; therefore, mitigation will help prevent or reduce the potential for exposure to PTS. The impact pile driving mitigation zone also extends beyond or into a portion of the average ranges to TTS; therefore, mitigation will help prevent or reduce the potential for exposure to all TTS or some higher levels of TTS, depending on the hearing group. Mitigation effectiveness and animal avoidance of higher sound levels were both factored into the impact pile driving analysis as most marine mammals should be able to easily move away from the expanding ensonified zone of TTS/PTS within 60 seconds, especially considering the soft start procedure, or avoid the zone altogether if they are outside of the immediate area upon startup. Marine mammals are likely to leave the immediate area of pile driving and extraction activities and be less likely to return as activities persist. However, some “naive” animals may enter the area during the short period of time when pile driving and extraction equipment is being re-positioned between piles. Therefore, an animal “refresh rate” of 10 percent was selected. This means that 10 percent of the single pile ZOI was added for each consecutive pile within a given 24-hour period to generate the daily ZOI per effect category. These daily ZOIs were then multiplied by the number of days of pile driving and pile extraction and Start Printed Page 66877then summed to generate a total ZOI per effect category (i.e., behavioral response, TTS, PTS). The small size of the mitigation zone and its close proximity to the observation platform will result in a high likelihood that Lookouts would be able to detect marine mammals throughout the mitigation zone.

PTS/TTS Thresholds

Comment 6: A commenter supported the weighting functions and associated thresholds as stipulated in Finneran (2016), which are the same as those used for Navy Phase III activities, but points to additional recent studies that provide additional behavioral audiograms (e.g., Branstetter et al. 2017; Kastelein et al. 2017b) and information on TTS (e.g., Kastelein et al. 2017a, 2017c). However, they commented that the Navy should provide a discussion of whether those new data corroborate the current weighting functions and associated thresholds.

Response: The NMFS Revised Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing (NMFS 2018) (Acoustic Technical Guidance), which was used in the assessment of effects for this action, compiled, interpreted, and synthesized the best available scientific information for noise-induced hearing effects for marine mammals to derive updated thresholds for assessing the impacts of noise on marine mammal hearing, including the articles that the commenter referenced that were published subsequent to the publication of the first version of 2016 Acoustic Technical Guidance. The new data included in those articles are consistent with the thresholds and weighting functions included in the current version of the Acoustic Technical Guidance (NMFS 2018).

NMFS will continue to review and evaluate new relevant data as it becomes available and consider the impacts of those studies on the Acoustic Technical Guidance to determine what revisions/updates may be appropriate. Thus far, no new information has been published or otherwise conveyed that would fundamentally change the assessment of impacts or conclusions of this rule.

Comment 7: Commenters commented that the criteria that the agency has produced to estimate temporary threshold shift (TTS) and permanent threshold shift (PTS) in marine mammals are erroneous and non-conservative. Commenters cited multiple purported issues with NMFS' Acoustic Technical Guidance, such as pseudo-replication and inconsistent treatment of data, broad extrapolation from a small number of individuals, and disregarding “non-linear accumulation of uncertainty.” Commenters suggested that NMFS not rely exclusively on its auditory guidance for determining Level A harassment take, but should at a minimum retain the historical 180-dB rms Level A harassment threshold as a “conservative upper bound” or conduct a “sensitivity analysis” to “understand the potential magnitude” of the supposed errors.

Response: NMFS disagrees with this characterization of the Acoustic Technical Guidance and the associated recommendation. The Acoustic Technical Guidance is a compilation, interpretation, and synthesis of the scientific literature that provides the best scientific information regarding the effects of anthropogenic sound on marine mammals' hearing. The technical guidance was classified as a Highly Influential Scientific Assessment and, as such, underwent three independent peer reviews, at three different stages in its development, including a follow-up to one of the peer reviews, prior to its dissemination by NMFS. In addition, there were three separate public comment periods, during which time we received and responded to similar comments on the guidance (81 FR 51694), which we cross-reference here, and more recent public and interagency review under Executive Order 13795. This review process was scientifically rigorous and ensured that the Guidance represents the best scientific data available.

The Acoustic Technical Guidance updates the historical 180 dB rms injury threshold, which was based on professional judgement (i.e., no data were available on the effects of noise on marine mammal hearing at the time this original threshold was derived). NMFS disagrees with any suggestion that the use of the Acoustic Technical Guidance provides erroneous results. The 180-dB rms threshold is plainly outdated, as the best available science indicates that rms SPL is not even an appropriate metric by which to gauge potential auditory injury (whereas the scientific debate regarding behavioral harassment thresholds is not about the proper metric but rather the proper level or levels and how these may vary in different contexts).

Multiple studies from humans, terrestrial mammals, and marine mammals have demonstrated less TTS from intermittent exposures compared to continuous exposures with the same total energy because hearing is known to experience some recovery in between noise exposures, which means that the effects of intermittent noise sources such as tactical sonars are likely overestimated. Marine mammal TTS data have also shown that, for two exposures with equal energy, the longer duration exposure tends to produce a larger amount of TTS. Most marine mammal TTS data have been obtained using exposure durations of tens of seconds up to an hour, much longer than the durations of many tactical sources (much less the continuous time that a marine mammal in the field would be exposed consecutively to those levels), further suggesting that the use of these TTS data are likely to overestimate the effects of sonars with shorter duration signals.

Regarding the suggestion of pseudo-replication and erroneous models, since marine mammal hearing and noise-induced hearing loss data are limited, both in the number of species and in the number of individuals available, attempts to minimize pseudoreplication would further reduce these already limited data sets. Specifically, with marine mammal behavioral temporary threshold shift studies, behaviorally derived data are only available for two mid-frequency cetacean species (bottlenose dolphin, beluga) and two phocids (in-water) pinniped species (harbor seal and northern elephant seal), with otariid (in-water) pinnipeds and high-frequency cetaceans only having behaviorally-derived data from one species. Arguments from Wright (2015) regarding pseudoreplication within the TTS data are therefore largely irrelevant in a practical sense because there are so few data. Multiple data points were not included for the same individual at a single frequency. If multiple data existed at one frequency, the lowest TTS onset was always used. There is only a single frequency where TTS onset data exist for two individuals of the same species: 3 kHz for dolphins. Their TTS (unweighted) onset values were 193 and 194 dB re 1 μPa2s. Thus, NMFS believes that the current approach makes the best use of the given data. Appropriate means of reducing pseudoreplication may be considered in the future, if more data become available. Many other comments from Wright (2015) and the comments from Racca et al. (2015b) appear to be erroneously based on the idea that the shapes of the auditory weighting functions and TTS/PTS exposure thresholds are directly related to the audiograms; i.e., that changes to the composite audiograms would directly influence the TTS/PTS exposure functions (e.g., Wright (2015) describes weighting functions as “effectively the mirror image of an audiogram” (p. 2) and states, “The underlying goal was to estimate how Start Printed Page 66878much a sound level needs to be above hearing threshold to induce TTS.” (p. 3)). Both statements are incorrect and suggest a fundamental misunderstanding of the criteria/threshold derivation. This would require a constant (frequency-independent) relationship between hearing threshold and TTS onset that is not reflected in the actual marine mammal TTS data. Attempts to create a “cautionary” outcome by artificially lowering the composite audiogram thresholds would not necessarily result in lower TTS/PTS exposure levels, since the exposure functions are to a large extent based on applying mathematical functions to fit the existing TTS data.

Behavioral Harassment Thresholds

Comment 8: Commenters commented on what it asserts is NMFS' failure to set proper thresholds for behavioral impacts. Referencing the biphasic function that assumes an unmediated dose response relationship at higher received levels and a context-influenced response at lower received levels that NMFS uses to quantify behavioral harassment from sonar, Commenters commented that resulting functions depend on some inappropriate assumptions that tend to significantly underestimate effects. Commenters expressed concern that every data point that informs the agency's pinniped function, and nearly two-thirds of the data points informing the odontocete function (30/49), are derived from a captive animal study. Additionally, Commenters asserted that the risk functions do not incorporate (nor does NMFS apparently consider) a number of relevant studies on wild marine mammals. Commenters stated that it is not clear from the proposed rule, or from the Navy's recent technical report on acoustic “criteria and thresholds,” on which NMFS' approach in the rule is based, exactly how each of the studies that NMFS employed was applied in the analysis, or how the functions were fitted to the data, but the available evidence on behavioral response raises concerns that the functions are not conservative for some species. Commenters recommended NMFS make additional technical information available, including from any expert elicitation and peer review, so that the public can fully comment.

Response: The Criteria and Thresholds for U.S. Navy Acoustic and Explosive Impacts to Marine Mammals and Sea Turtles Technical Report (U.S. Department of the Navy, 2017) details how the Navy's proposed method, which was determined appropriate and adopted by NMFS, accounted for the differences in captive and wild animals in the development of the behavioral response functions. The Navy used the best available science, which has been reviewed by external scientists and approved by NMFS, in the analysis. The Navy and NMFS have utilized all available data that relate known or estimable received levels to observations of individual or group behavior as a result of sonar exposure (which is needed to inform the behavioral response function) for the development of updated thresholds. Limiting the data to the small number of field studies that include these necessary data would not provide enough data with which to develop the new risk functions. In addition, NMFS agrees with the assumptions made by the Navy, including the fact that captive animals may be less sensitive, in that the scale at which a moderate to severe response was considered to have occurred is different for captive animals than for wild animals, as the agency understands those responses will be different.

The new risk functions were developed in 2016, before several recent papers were published or the data were available. As new science is published, NMFS and the Navy continue to evaluate the information. The thresholds have been rigorously vetted among scientists and within the Navy community during expert elicitation and then reviewed by the public before being applied. It is unreasonable to revise and update the criteria and risk functions every time a new paper is published. These new and future papers provide additional information, and the Navy has already begun to consult them for updates to the thresholds in the future, when the next round of updated criteria will be developed. Thus far, no new information has been published or otherwise conveyed that would fundamentally change the assessment of impacts or conclusions of the HSTT FEIS/OEIS or this rule. To be included in the behavioral response function, data sets need to relate known or estimable received levels to observations of individual or group behavior. Melcon et al. (2012) does not relate observations of individual/group behavior to known or estimable received levels (at that individual/group). In Melcon et al. (2012), received levels at the HARP buoy averaged over many hours are related to probabilities of D-calls, but the received level at the blue whale individuals/group are unknown.

As noted, the derivation of the behavioral response functions is provided in the 2017 technical report titled Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III). The appendices to this report detail the specific data points used to generate the behavioral response functions. Data points come from published data that is readily available and cited within the technical report.

Comment 9: Commenters stated concerns with the use of distance “cut-offs” in the behavioral harassment thresholds, and one commenter recommended that NMFS refrain from using cut-off distances in conjunction with the Bayesian BRFs and re-estimate the numbers of marine mammal takes based solely on the Bayesian BRFs.

Response: The consideration of proximity (cut-off distances) was part of the criteria developed in consultation between the Navy and NMFS, is appropriate based on the best available science which shows that marine mammal responses to sound vary based on both sound level and distance, and was applied within the Navy's acoustic effects model. The derivation of the behavioral response functions and associated cut-off distances is provided in the 2017 technical report titled Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III). To account for non-applicable contextual factors, all available data on marine mammal reactions to actual Navy activities and other sound sources (or other large scale activities such as seismic surveys when information on proximity to sonar sources is not available for a given species group) were reviewed to find the farthest distance to which significant behavioral reactions were observed. These distances were rounded up to the nearest 5 or 10 km interval, and for moderate to large scale activities using multiple or louder sonar sources, these distances were greatly increased—doubled in most cases. The Navy's BRFs applied within these distances provide technically sound methods reflective of the best available science to estimate of impact and potential take under military readiness for the actions analyzed within the HSTT FEIS/OEIS and included in these regulations. NMFS has independently assessed the Navy's behavioral harassment thresholds and believes that they appropriately apply the best available science and it is not necessary to recalculate take estimates.

The commenter also specifically expressed concern that distance “cut-offs” alleviate some of the exposures that would otherwise have been counted if the received level alone were considered. It is unclear why the commenter finds this inherently inappropriate, as this is what the data show. As noted previously, there are Start Printed Page 66879multiple studies illustrating that in situations where one would expect a behavioral harassment because of the received levels at which previous responses were observed, it has not occurred when the distance from the source was larger than the distance of the first observed response.

Comment 10: Regarding cut-off distances, Commenters noted that dipping sonar appears to be a significant predictor of deep-dive rates in beaked whales on Southern California Anti-submarine Warfare Range (SOAR), with the dive rate falling significantly (e.g., to 35 percent of that individual's control rate) during sonar exposure, and likewise appears associated with habitat abandonment. Importantly, these effects were observed at substantially greater distances (e.g., 30 or more km) from dipping sonar than would otherwise be expected given the systems' source levels and the beaked whale response thresholds developed from research on hull-mounted sonar. Commenters suggested that the analysis, and associated cut-off distances, do not properly consider the impacts of dipping sonar.

Response: The Navy relied upon the best science that was available to develop the behavioral response functions in consultation with NMFS. The Navy's current beaked whale BRF acknowledges and incorporates the increased sensitivity observed in beaked whales during both behavioral response studies and during actual Navy training events, as well as the fact that dipping sonar can have greater effects than some other sources with the same source level. Specifically, the distance cut-off for beaked whales is 50 km, larger than any other group. Moreover, although dipping sonar has a significantly lower source level than hull-mounted sonar, it is included in the category of sources with larger distance cut-offs, specifically in acknowledgement of its unpredictability and association with observed effects. This means that “takes” are reflected at lower received levels that would have been excluded because of the distance for other source types.

The referenced article (Associating patterns in movement and diving behavior with sonar use during military training exercises: A case study using satellite tag data from Cuvier's beaked whales at the Southern California Anti-submarine Warfare Range (Falcone et al., 2017) was not available at the time the BRFs were developed. However, NMFS and the Navy have reviewed the article and concur that neither this article nor any other new information that has been published or otherwise conveyed since the proposed rule was published would significantly change the assessment of impacts or conclusions in the HSTT FEIS/OEIS or in this rulemaking. Nonetheless, the new information and data presented in the new article were recently thoroughly reviewed by the Navy and will be quantitatively incorporated into future behavioral response functions, as appropriate for data available at the time that new functions are needed to inform new analyses.

Furthermore, ongoing Navy funded beaked whale monitoring at the same site where the dipping sonar tests were conducted has not documented habitat abandonment by beaked whales. Passive acoustic detections of beaked whales have not significantly changed over eight years of monitoring (DiMarzio et al., 2018). From visual surveys in the area since 2006 there have been repeated sightings of: The same individual beaked whale, beaked whale mother-calf pairs, and beaked whale mother-calf pairs with mothers on their second calf (Schorr et al., 2018). Satellite tracking studies of beaked whale documented high site fidelity to this area (Schorr et al., 2018).”

Comment 11: Regarding the behavioral thresholds for explosives, Commenters recommended that NMFS estimate and ultimately authorize behavior takes of marine mammals during all explosive activities, including those that involve single detonations.

Response: The derivation of the explosive injury criteria is provided in the 2017 technical report titled Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III), and NMFS has applied the general rule a commenter referenced to single explosives for years, i.e., that marine mammals are unlikely to respond to a single instantaneous detonation in a manner that would rise to the level of a take. Neither NMFS nor the Navy are aware of evidence to support the assertion that animals will have significant behavioral reactions (i.e., those that would rise to the level of a take) to temporally and spatially isolated explosions. The Navy has been monitoring detonations since the 1990s and has not observed these types of reactions. TTS and all other higher order impacts are assessed for all training and testing events that involve the use of explosives or explosive ordnance.

Further, to clarify, the current take estimate framework does not preclude the consideration of animals being behaviorally disturbed during single explosions as they are counted as “taken by Level B harassment” if they are exposed above the TTS threshold, which is only 5 dB higher than the behavioral harassment threshold. We acknowledge in our analysis that individuals exposed above the TTS threshold may also be behaviorally harassed and those potential impacts are considered in the negligible impact determination.

All of the Navy's monitoring projects, reports, and publications are available on the marine species monitoring web page (https://www.navymarinespeciesmonitoring.us/​). NMFS will continue to review applicable monitoring and science data and consider modifying these criteria when and if new information suggests it is appropriate.

Mortality and injury thresholds for explosions

Comment 12: A commenter recommended that NMFS require the Navy to (1) explain why the constants and exponents for onset mortality and onset slight lung injury thresholds for Phase III have been amended, (2) ensure that the modified equations are correct, and (3) specify any additional assumptions that were made.

Response: The derivation of the explosive injury equations, including any assumptions, is provided in the 2017 technical report titled Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III). It is our understanding that the constants and exponents for onset mortality and onset slight lung injury were amended by the Navy since Phase II to better account for the best available science. Specifically, the equations were modified in Phase III to fully incorporate the injury model in Goertner (1982), specifically to include lung compression with depth. NMFS independently reviewed and concurred with this approach.

Comment 13: A commenter commented that the Navy only used the onset mortality and onset slight lung injury criteria to determine the range to effects, while it used the 50 percent mortality and 50 percent slight lung injury criteria to estimate the numbers of marine mammal takes. The commenter believes that this approach is inconsistent with the manner in which the Navy estimated the numbers of takes for PTS, TTS, and behavior for explosive activities. All of those takes have been and continue to be based on onset, not 50-percent values. The commenter commented on circumstances of the deaths of multiple common dolphins during one of the Navy's underwater detonation events in March 2011 (Danil and St. Leger, 2011) Start Printed Page 66880and indicated that the Navy's mitigation measures are not fully effective, especially for explosive activities. The commenter believes it would be more prudent for the Navy to estimate injuries and mortalities based on onset rather than a 50-percent incidence of occurrence. The Navy did indicate that it is reasonable to assume for its impact analysis—thus its take estimation process—that extensive lung hemorrhage is a level of injury that would result in mortality for a wild animal (Department of the Navy 2017a). Thus, the commenter comments that it is unclear why the Navy did not follow through with that premise. The commenter recommends that NMFS use onset mortality, onset slight lung injury, and onset GI tract injury thresholds to estimate both the numbers of marine mammal takes and the respective ranges to effect.

Response: Based on an extensive review of the incident referred to by the commenter, in coordination with NMFS the Navy revised and updated the mitigation for these types of events. There have been no further incidents since these mitigation changes were instituted in 2011.

The Navy used the range to one percent risk of mortality and injury (referred to as “onset” in the Draft EIS/OEIS) to inform the development of mitigation zones for explosives. In all cases, the mitigation zones for explosives extend beyond the range to one percent risk of non-auditory injury, even for a small animal (representative mass = 5 kg). In the FEIS/OEIS, the Navy has clarified that the “onset” non-auditory injury and mortality criteria are actually one percent risk criteria.

Over-predicting impacts, which would occur with the use of one percent non-auditory injury risk criteria in the quantitative analysis, would not afford extra protection to any animal. The Navy, in coordination with NMFS, has determined that the 50 percent incidence of occurrence is a reasonable representation of a potential effect and appropriate for take estimation.

Although the commenter implies that the Navy did not use extensive lung hemorrhage as indicative of mortality, that statement is incorrect. Extensive lung hemorrhage is assumed to result in mortality, and the explosive mortality criteria are based on extensive lung injury data See the 2017 technical report titled Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III).

Range to Effects

Comment 14: One commenter noted that regarding TTS, the ranges to effect provided in Table 25 of the Federal Register notice of proposed rulemaking and Table 6-4 of the LOA application appear to be incorrect. The ranges for LF cetaceans should increase with increasing sonar emission time. Therefore, the commenter recommended that NMFS determine what the appropriate ranges to TTS for bin LF5 should be and amend the ranges for the various functional hearing groups in the tables accordingly.

Response: The error in the table has been fixed; specifically, the ranges for MF cetaceans have been revised. Note that the distances are shorter than initially provided in the proposed rule, indicating that the impacts of exposure to this bin are fewer than initially implied by the table. Regardless, the error was only associated with the information presented in this table; there was no associated error in any distances used in the take estimation, and both the take estimates and our findings remain the same.

Mitigation and Avoidance Calculations

Comment 15: Commenters cited concerns that there was not enough information by which to evaluate the Navy's post-modeling calculations to account for mitigation and avoidance and imply that Level A takes and mortality takes may be underestimated. A commenter recommended that NMFS (1) authorize the total numbers of model-estimated Level A harassment (PTS) and mortality takes rather than reduce the estimated numbers of takes based on the Navy's post-model analyses and (2) use those numbers, in addition to the revised Level B harassment takes, to inform its negligible impact determination analyses.

Response: The consideration of marine mammal avoidance and mitigation effectiveness is integral to the Navy's overall analysis of impacts from sonar and explosive sources. NMFS has independently evaluated the method and agrees that it is appropriately applied to augment the model in the prediction and authorization of injury and mortality as described in the rule. Details of this analysis are provided in the Navy's 2018 technical report titled Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing; additional information on the mitigation analysis also has been included in the final rule.

Sound levels diminish quickly below levels that could cause PTS. Studies have shown that all animals observed avoid areas well beyond these zones; therefore, the vast majority of animals are likely to avoid sound levels that could cause injury to their ear. As discussed in the Navy's 2018 technical report titled Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing, animats in the Navy's acoustic effects model do not move horizontally or “react” to sound in any way. The current best available science based on a growing body of behavioral response research shows that animals do in fact avoid the immediate area around sound sources to a distance of a few hundred meters or more depending upon the species. Avoidance to this distance greatly reduces the likelihood of impacts to hearing such as TTS and PTS.

Specifically, behavioral response literature, including the recent 3S and SOCAL BRS studies, indicate that the multiple species from different cetacean suborders do in fact avoid approaching sound sources by a few hundred meters or more, which would reduce received sound levels for individual marine mammals to levels below those that could cause PTS. The ranges to PTS for most marine mammal groups are within a few tens of meters and the ranges for the most sensitive group, the HF cetaceans, average about 200 m, to a maximum of 270 m in limited cases.

As discussed in the Navy's 2018 technical report titled Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing, the Navy's acoustic effects model does not consider procedural mitigations (i.e., power-down or shut-down of sonars, or pausing explosive activities when animals are detected in specific zones adjacent to the source), which necessitates consideration of these factors in the Navy's overall acoustic analysis. Credit taken for mitigation effectiveness is extremely conservative. For example, if Lookouts can see the whole area, they get credit for it in the calculation; if they can see more than half the area, they get half credit; if they can see less than half the area, they get no credit. Not considering animal avoidance and mitigation effectiveness would lead to a great overestimate of injurious impacts. NMFS concurs with the analytical approach used, i.e., we believe the estimated Level A take numbers represent the maximum number of these takes that are likely to occur and it would not be appropriate to authorize a higher number or consider a higher number in the negligible impact analysis.Start Printed Page 66881

Last, the Navy's 2018 technical report titled Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing very clearly explains in detail how species sightability, the Lookout's ability to observe the range to PTS (for sonar and other transducers) and mortality (for explosives), the portion of time when mitigation could potentially be conducted during periods of reduced daytime visibility (to include inclement weather and high sea state) and the portion of time when mitigation could potentially be conducted at night, and the ability for sound sources to be positively controlled (powered down) are considered in the post-modeling calculation to account for mitigation and avoidance. It is not necessary to view the many tables of numbers generated in the assessment to evaluate the method.

Comment 16: A commenter stated in regards to the method in which the Navy's post-model calculation considers avoidance specifically (i.e., assuming animals present beyond the range of PTS for the first few pings will be able to avoid it and incur only TTS, which results in a 95 percent reduction in the number of estimated PTS takes predicted by the model), given that sound sources are moving, it may not be until later in an exercise that the animal is close enough to experience PTS, and it is those few close pings that contribute to the potential to experience PTS. An animal being beyond the PTS zone initially has no bearing on whether it will come within close range later during an exercise since both sources and animals are moving. In addition, Navy vessels may move faster than the ability of the animals to evacuate the area. The Navy should have been able to query the dosimeters of the animats to verify whether its 5-percent assumption was valid. Commenters are concerned that this method underestimates the number of PTS takes.

Response: The consideration of marine mammals avoiding the area immediately around the sound source is provided in the Navy's 2018 technical report titled Quantitative Analysis for Estimating Acoustic and Explosive Impacts to Marine Mammals and Sea Turtles. As the commenter correctly articulates: “For avoidance, the Navy assumed that animals present beyond the range to onset PTS for the first three to four pings are assumed to avoid any additional exposures at levels that could cause PTS. That equated to approximately 5 percent of the total pings or 5 percent of the overall time active; therefore, 95 percent of marine mammals predicted to experience PTS due to sonar and other transducers were instead assumed to experience TTS.” In regard to the comment about vessels moving faster than animals' ability to get out of the way, as discussed in the Navy's 2018 technical report titled Quantitative Analysis for Estimating Acoustic and Explosive Impacts to Marine Mammals and Sea Turtles, animats in the Navy's acoustic effects model do not move horizontally or “react” to sound in any way, necessitating the additional step of considering animal avoidance of close-in PTS zones. NMFS independently reviewed this approach and concurs that it is fully supported by the best available science. Based on a growing body of behavioral response research, animals do in fact avoid the immediate area around sound sources to a distance of a few hundred meters or more depending upon the species. Avoidance to this distance greatly reduces the likelihood of impacts to hearing such as TTS and PTS, respectively. Specifically, the ranges to PTS for most marine mammal groups are within a few tens of meters and the ranges for the most sensitive group, the HF cetaceans, average about 200 m, to a maximum of 270 m in limited cases. Querying the dosimeters of the animats would not produce useful information since, as discussed previously, the animats do not move in the horizontal and are not programmed to “react” to sound or any other stimulus. The commenter references comments that they have previously submitted on the Navy's Gulf of Alaska incidental take regulations and we refer the commenter to NMFS' responses, which were included in the Federal Register document announcing the issuance of the final regulations (82 FR 19572, April 27, 2017).

Underestimated Beaked Whale Injury and Mortality

Comment 17: A commenter commented that the Navy and NMFS both underestimate take for Cuvier's beaked whales because they are extremely sensitive to sonar. A new study of Cuvier's beaked whales in Southern California exposed to mid and high-power sonar confirmed that they modify their diving behavior up to 100-km away (Falcone et al., 2017). The commenter asserted that this science disproves NMFS' assumption that beaked whales will find suitable habitat nearby within their small range. This modified diving behavior, which was particularly strong when exposed to mid-power sonar, indicates disruption of feeding. Accordingly, impacts on Cuvier's beaked whales could include interference with essential behaviors that will have more than a negligible impact on this species. In addition, Lookouts and shutdowns do not protect Cuvier's beaked whales from Navy sonar because this is a deep-diving species that is difficult to see from ships.

Response: Takes of Cuvier's beaked whales are not underestimated. The behavioral harassment threshold for beaked whales has two components, both of which consider the sensitivity of beaked whales. First, the biphasic behavioral harassment function for beaked whales, which is based on data on beaked whale responses, has a significantly lower mid-point than other groups and also reflects a significantly higher probability of “take” at lower levels (e.g., close to 15 percent at 120 dB). Additionally, the distance cut-off used for beaked whales is farther than for any other group (50 km, for both the MF1 and MF4 bins, acknowledging the fact that the unpredictability of dipping sonar likely results in takes at greater distances than other more predictable sources of similar levels). Regarding the referenced article, the commenter is selectively citing only part of it. The study, which compiles information from multiple studies, found that shallow dives were predicted to increase in duration as the distance to both high-and mid-power MFAS sources decreased, beginning at approximately 100 km away and, specifically, the differences only varied from approximately 20 minutes without MFAS to about 24 minutes with MFAS at the closest distance (i.e., the dive time varied from 20 to 24 minutes over the distance of 100 km away to the closest distance measured). Further, the same article predicted that deep dive duration (which is more directly associated with feeding and linked to potential energetic effects) was predicted to increase with proximity to mid-power MFAS from approximately 60 minutes to approximately 90 minutes beginning at around 40 km (10 dives). There were four deep dives exposed high-power MFAS within 20 km, the distance at which deep dive durations increased with the lower power source types. Other responses to MFAS included deep dives that were shorter than typical and shallower, and instances where there were no observed responses at closer distances. The threshold for Level B harassment is higher than just “any measurable response” and NMFS and the Navy worked closely together to identify behavioral response functions and distance cut-offs that reflect the best available science to identify when Start Printed Page 66882marine mammal behavioral patterns will be disrupted to a point where they are abandoned or significantly altered. Further, the take estimate is in no way based on an assumption that beaked whales will always be sighted by Lookouts—and adjustment to account for Lookout effectiveness considers the variable detectability of different stocks. In this rule, both the take estimate and the negligible impact analysis appropriately consider the sensitivity of, and scale of impacts to (we address impacts to feeding and energetics), Cuvier's (and all) beaked whales.

Comment 18: A commenter commented that NMFS is underestimating serious injury and mortality for beaked whales. A commenter noted the statement in the proposed rule that because a causal relationship between Navy MFAS use and beaked whale strandings has not been established in all instances, and that, in some cases, sonar was considered to be only one of several factors that, in aggregate, may have contributed to the stranding event, NMFS does “not expect strandings, serious injury, or mortality of beaked whales to occur as a result of training activities.” (83 FR at 30007). The commenter asserted that this opinion is inconsistent with best available science and does not take into account the fact that the leading explanation for the mechanism of sonar-related injuries—that whales suffer from bubble growth in organs that is similar to decompression sickness, or “the bends” in human divers—has now been supported by numerous papers. At the same time, the commenter argued that NMFS fails to seriously acknowledge that sonar can seriously injure or kill marine mammals at distances well beyond those established for permanent hearing loss (83 FR 29916) and dismisses the risk of stranding and other mortality events (83 FR 30007) based on the argument that such effects can transpire only under the same set of circumstances that occurred during known sonar-related events—an assumption that is arbitrary and capricious. In conclusion, a commenter argued that none of NMFS' assumptions regarding the expected lack of serious injury and mortality for beaked whales are supported by the record, and all lead to an underestimation of impacts.

Response: A commenter's characterization of NMFS' analysis is incorrect. NMFS does not disregard the fact that it is possible for naval activities using hull-mounted tactical sonar to contribute to the death of marine mammals in certain circumstances (that are not present in the HSTT Study Area) via strandings resulting from behaviorally mediated physiological impacts or other gas-related injuries. NMFS discussed these potential causes and outlined the few cases where active naval sonar (in the United States or, largely, elsewhere) had either potentially contributed to or (as with the Bahamas example) been more definitively causally linked with marine mammal strandings in the proposed rule. As noted, there are a suite of factors that have been associated with these specific cases of strandings directly associated with sonar (steep bathymetry, multiple hull-mounted platforms using sonar simultaneously, constricted channels, strong surface ducts, etc.) that are not present together in the HSTT Study Area and during the specified activities (and which the Navy takes care across the world not to operate under without additional monitoring). There have been no documented beaked whale mortalities from Navy activities within the HSTT Study Area. Further, none of the beaked whale strandings causally associated with Navy sonar stranding are in the Pacific. For these reasons, NMFS does not anticipate that the Navy's HSTT training or testing activities will result in beaked whale marine mammal strandings, and none are authorized. Furthermore, ongoing Navy funded beaked whale monitoring at a heavily used training and testing area in SOCAL has not documented mortality or habitat abandonment by beaked whales. Passive acoustic detections of beaked whales have not significantly changed over eight years of monitoring (DiMarzio et al., 2018). From visual surveys in the area since 2006 there have been repeated sightings of: the same individual beaked whale, beaked whale mother-calf pairs, and beaked whale mother-calf pairs with mothers on their second calf (Schorr et al., 2018). Satellite tracking studies of beaked whale documented high site fidelity to this area even though the study area is located in one of the most used Navy areas in the Pacific (Schorr et al., 2018).

Ship Strike

Comment 19: A commenter commented that the Navy's current approach to determine the risk of a direct vessel collision with marine mammals is flawed and fails to account for the likelihood that ship strikes since 2009 were unintentionally underreported. The commenters noted that vessel collisions are generally underreported in part because they can be difficult to detect, especially for large vessels and that the distribution, being based on reported strikes, does not account for this problem. Additionally, the commenter asserted that the Navy's analysis does not address the potential for increased strike risk of non-Navy vessels as a consequence of acoustic disturbance. For example, some types of anthropogenic noise have been shown to induce near-surfacing behavior in right whales, increasing the risk of ship-strike—by not only the source vessel but potentially by third-party vessels in the area—at relatively moderate levels of exposure (Nowacek et al., 2004). An analysis based on reported strikes by Navy vessels per se does not account for this additional risk. In assessing ship-strike risk, the Navy should include offsets to account for potentially undetected and unreported collisions.

Response: While NMFS agrees that broadly speaking the number of total ship strikes may be underestimated due to incomplete information from other sectors (shipping, etc.), NMFS is confident that whales struck by Navy vessels are detected and reported, and Navy strikes are the numbers used in NMFS' analysis to support the authorized number of strikes. Navy ships have multiple Lookouts, including on the forward part of the ship that can visually detect a hit whale (which has occasionally occurred), in the unlikely event ship personnel do not feel the strike. The Navy's strict internal procedures and mitigation requirements include reporting of any vessel strikes of marine mammals, and the Navy's discipline, extensive training (not only for detecting marine mammals, but for detecting and reporting any potential navigational obstruction), and strict chain of command give NMFS a high level of confidence that all strikes actually get reported. Accordingly, NMFS is confident that the information used to support the analysis is accurate and complete.

There is no evidence that Navy training and testing activities (or other acoustic activities) increase the risk of nearby non-Navy vessels (or other nearby Navy vessels not involved in the referenced training or testing) striking marine mammals. More whales are struck by non-Navy vessels off California in areas outside of the HSTT Study Area such as approaches to Los Angeles and San Francisco.

Mitigation and Monitoring

Least Practicable Adverse Impact Determination

Comment 20: A commenter commented that deaths of, or serious injuries to marine mammals that occur pursuant to activities conducted under an incidental take authorization, while Start Printed Page 66883perhaps negligible to the overall health and productivity of the species or stock and of little consequence at that level, nevertheless are clearly adverse to the individuals involved and results in some quantifiable (though negligible) adverse impact on the population; it reduces the population to some degree. Under the least practicable adverse impact requirement, and more generally under the purposes and policies of the MMPA, the commenter asserted that Congress embraced a policy to minimize, whenever practicable, the risk of killing or seriously injuring a marine mammal incidental to an activity subject to section 101(a)(5)(A), including providing measures in an authorization to eliminate or reduce the likelihood of lethal taking. The commenter recommended that NMFS address this point explicitly in its analysis and clarify whether it agrees that the incidental serious injury or death of a marine mammal always should be considered an adverse impact for purposes of applying the least practicable adverse impact standard.

Response: NMFS disagrees that it is necessary or helpful to explicitly address the point the commenter raises in the general description of the least practicable adverse impact standard. The discussion of this standard already notes that there can be population-level impacts that fall below the “negligible” standard, but that are still appropriate to mitigate under the least practicable adverse impact standard. It is always NMFS' practice to mitigate mortality to the greatest degree possible, as death is the impact that is most easily linked to reducing the probability of adverse impacts to populations. However, we cannot agree that one mortality will always decrease any population in a quantifiable or meaningful way. For example, for very large populations, one mortality may fall well within typical known annual variation and not have any effect on population rates. Further, we do not understand the problem that the commenter's recommendation is attempting to fix. Applicants generally do not express reluctance to mitigate mortality, and we believe that modifications of this nature would confuse the issue.

Comment 21: A commenter recommended that NMFS address the habitat component of the least practicable adverse impact provision in greater detail. It asserted that NMFS' discussion of critical habitat, marine sanctuaries, and BIAs in the proposed rule is not integrated with the discussion of the least practicable adverse impact standard. It would seem that, under the least practicable adverse impact provision, adverse impacts on important habitat should be avoided whenever practicable. Therefore, to the extent that activities would be allowed to proceed in these areas, NMFS should explain why it is not practicable to constrain them further.

Response: Marine mammal habitat value is informed by marine mammal presence and use and, in some cases, there may be overlap in measures for the species or stock directly and for use of habitat. In this rule, we have identified time-area mitigations based on a combination of factors that include higher densities and observations of specific important behaviors of marine mammals themselves, but also that clearly reflect preferred habitat (e.g., calving areas in Hawaii, feeding areas SOCAL). In addition to being delineated based on physical features that drive habitat function (e.g., bathymetric features, among others for some BIAs), the high densities and concentration of certain important behaviors (e.g., feeding) in these particular areas clearly indicate the presence of preferred habitat. The commenter seems to suggest that NMFS must always consider separate measures aimed at marine mammal habitat; however, the MMPA does not specify that effects to habitat must be mitigated in separate measures, and NMFS has clearly identified measures that provide significant reduction of impacts to both “marine mammal species and stocks and their habitat,” as required by the statute.

Comment 22: A commenter recommended that NMFS rework its evaluation criteria for applying the least practicable adverse impact standard to separate the factors used to determine whether a potential impact on marine mammals or their habitat is adverse and whether possible mitigation measures would be effective. In this regard, the commenter asserted that it seems as though the proposed “effectiveness” criterion more appropriately fits as an element of practicability and should be addressed under that prong of the analysis. In other words, a measure not expected to be effective should not be considered a practicable means of reducing impacts.

Response: In the Mitigation Measures section, NMFS has explained in detail our interpretation of the least practicable adverse impact standard, the rationale for our interpretation, and our approach for implementing our interpretation. The ability of a measure to reduce effects on marine mammals is entirely related to its “effectiveness” as a measure, whereas the effectiveness of a measure is not connected to its practicability. The commenter provides no support for its argument, and NMFS has not implemented the Commission's suggestion.

Comment 23: A commenter recommended that NMFS recast its conclusions to provide sufficient detail as to why additional measures either are not needed (i.e., there are no remaining adverse impacts) or would not be practicable to implement. The commenter states that the most concerning element of NMFS' implementation of the least practicable adverse impact standard is its suggestion that the mitigation measures proposed by the Navy will “sufficiently reduce impacts on the affected mammal species and stocks and their habitats” (83 FR 11045). That phrase suggests that NMFS is applying a “good-enough” standard to the Navy's activities. Under the statutory criteria, however, those proposed measures are “sufficient” only if they have either (1) eliminated all adverse impacts on marine mammal species and stocks and their habitat or (2) if adverse impacts remain, it is impracticable to reduce them further.

Response: The statement that the commenter references does not indicate that NMFS applies a “good-enough” standard to determining least practicable adverse impact. Rather, it indicates that the mitigation measures are sufficient to meet the statutory legal standard. In addition, as NMFS has explained in our description of the least practicable adverse impact standard, NMFS does not view the necessary analysis through the yes/no lens that the commenter seeks to prescribe. Rather, NMFS' least practicable adverse impact analysis considers both the reduction of adverse effects and their practicability. Further, since the proposed rule was published, the Navy and NMFS have evaluated additional measures in the context of both their practicability and their ability to further reduce impacts to marine mammals and have determined that the addition of several measures (see Mitigation Measures) is appropriate. Regardless, beyond these new additional measures, where the Navy's HSTT activities are concerned, the Navy has indicated that further procedural or area mitigation of any kind (beyond that prescribed in this final rule) would be entirely impracticable. NMFS has reviewed documentation and analysis provided by the Navy explaining how and why specific procedural and geographic based mitigation measures impact practicability, and NMFS concurs with these assessments and has determined that the mitigation measures outlined in the final rule satisfy the statutory standard and that any adverse Start Printed Page 66884impacts that remain are unable to be further mitigated.

Comment 24: A commenter recommended that any “formal interpretation” of the least practicable adverse impact standard by NMFS be issued in a stand-alone, generally applicable rulemaking (e.g., in amendments to 50 CFR 216.103 or 216.105) or in a separate policy directive, rather than in the preambles to individual proposed rules.

Response: We appreciate the commenter's recommendation and may consider the recommended approaches in the future. We note, however, that providing relevant explanations in a proposed incidental take rule is an effective and efficient way to provide information to the reader and solicit focused input from the public, and ultimately affords the same opportunities for public comment as a stand-alone rulemaking would. NMFS has provided similar explanations of the least practicable adverse impact standard in other recent section 101(a)(5)(A) rules, including: U.S. Navy Operations of Surveillance Towed Array Sensor System Low Frequency Active (SURTASS LFA) Sonar; Geophysical Surveys Related to Oil and Gas Activities in the Gulf of Mexico; and the final rule for U.S. Navy Training and Testing Activities in the Atlantic Fleet Study Area.

Comment 25: A commenter cited two judicial decisions and commented that the “least practicable adverse impact” standard has not been met. A commenter stated that contrary to the Pritzker Court decision, NMFS, while clarifying that population-level impacts are mitigated “through the application of mitigation measures that limit impacts to individual animals,” has again set population-level impact as the basis for mitigation in the proposed rule. Because NMFS' mitigation analysis is opaque, it is not clear what practical effect this position may have on its rulemaking. A commenter stated that the proposed rule is also unclear in its application of the “habitat” emphasis in the MMPA's mitigation standard, and that while NMFS' analysis is opaque, its failure to incorporate or even, apparently, to consider viable time-area measures suggests that the agency has not addressed this aspect of the Pritzker decision. A commenter argues that the MMPA sets forth a “stringent standard” for mitigation that requires the agency to minimize impacts to the lowest practicable level, and that the agency must conduct its own analysis and clearly articulate it: it “cannot just parrot what the Navy says.”

Response: NMFS disagrees with much of what a commenter asserts. When a suggested or recommended mitigation measure is impracticable, NMFS has explored variations of that mitigation to determine if a practicable form of related mitigation exists. This is clearly illustrated in NMFS' independent mitigation analysis process explained in this rule. First, the type of mitigation required varies by mitigation area, demonstrating that NMFS has engaged in a site-specific analysis to ensure mitigation is tailored when practicability demands, i.e., some forms of mitigation were practicable in some areas but not others. Examples of NMFS' analysis on this issue appear throughout the rule. For instance, while it was not practicable for the Navy to include a mitigation area for the Tanner-Cortes blue whale BIA, the Navy did agree to expand mitigation protection to all of the other blue whale BIAs in the SOCAL region. Additionally, while the Navy cannot alleviate all training in the mitigation areas that protect small resident odontocete populations in Hawaii, has further expanded the protections in those areas such that it does not use explosives or MFAS in the areas (MF1 bin in both areas, MF4 bin in the Hawaii Island area). Nonetheless, NMFS agrees that the agency must conduct its own analysis, which it has done here, and not just accept what is provided by the Navy. That does not mean, however, that NMFS cannot review the Navy's analysis of effectiveness and practicability, and concur with those aspects of the Navy's analysis with which NMFS agrees. A commenter seems to suggest that NMFS must describe in the rule in detail the rationale for not adopting every conceivable permutation of mitigation, which is neither reasonable nor required by the MMPA. NMFS has described our well-reasoned process for identifying the measures needed to meet the least practicable adverse impact standard in the Mitigation Measures section in this rule, and we have followed the approach described there when analyzing potential mitigation for the Navy's activities in the HSTT Study Area. Discussion regarding specific recommendations for mitigation measures provided by a commenter on the proposed rule are discussed separately.

Procedural Mitigation Effectiveness and Recommendations

Comment 26: A commenter commented that the Navy's proposed mitigation zones are similar to the zones previously used during Phase II activities and are intended, based on the Phase III HSTT DEIS/OEIS, to avoid the potential for marine mammals to be exposed to levels of sound that could result in injury (i.e., PTS). However, the commenter believed that Phase III proposed mitigation zones would not protect various functional hearing groups from PTS. For example, the mitigation zone for an explosive sonobuoy is 549 m but the mean PTS zones range from 2,113-3,682 m for HF. Similarly, the mitigation zone for an explosive torpedo is 1,920 m but the mean PTS zones range from 7,635-10,062 m for HF, 1,969-4,315 m for LF, and 3,053-3,311 for PW. The appropriateness of such zones is further complicated by platforms firing munitions (e.g., for missiles and rockets) at targets that are 28 to 139 km away from the firing platform. An aircraft would clear the target area well before it positions itself at the launch location and launches the missile or rocket. Ships, on the other hand, do not clear the target area before launching the missile or rocket. In either case, marine mammals could be present in the target area unbeknownst to the Navy at the time of the launch.

Response: NMFS is aware that some mitigation zones do not fully cover the area in which an animal from a certain hearing group may incur PTS. For this small subset of circumstances, NMFS discussed potential enlargement of the mitigation zones with the Navy, but concurred with the Navy's assessment that further enlargement would be impracticable. Specifically, the Navy explained that explosive mitigation zones, as discussed in Chapter 5 (Mitigation) of the HSTT FEIS/OEIS, any additional increases in mitigation zone size (beyond what is depicted for each explosive activity), or additional observation requirements would be impracticable to implement due to implications for safety, sustainability, the Navy's ability to meet Title 10 requirements to successfully accomplish military readiness objectives, and the Navy's ability to conduct testing associated with required acquisition milestones or as required on an as-needed basis to meet operational requirements. Additionally, Navy Senior Leadership has approved and determined that the mitigation detailed in Chapter 5 (Mitigation) of the HSTT FEIS/OEIS provides the greatest extent of protection that is practicable to implement. The absence of mitigation to avoid all Level A harassment in some of these circumstances has been analyzed, however, and the Navy is authorized for any of these Level A harassment takes that may occur.Start Printed Page 66885

Comment 27: One commenter made several comments regarding visual and acoustic detection as related to mitigating impacts that can cause injury. The commenter noted that the Navy indicated in the HSTT DEIS/OEIS that Lookouts would not be 100 percent effective at detecting all species of marine mammals for every activity because of the inherent limitations of observing marine species and because the likelihood of sighting individual animals is largely dependent on observation conditions (e.g., time of day, sea state, mitigation zone size, observation platform). The Navy has been collaborating with researchers at the University of St. Andrews to study Navy Lookout effectiveness and the commenter anticipates that the Lookout effectiveness study will be very informative once completed, but notes that in the interim, the preliminary data do provide an adequate basis for taking a precautionary approach. The commenter believed that rather than simply reducing the size of the mitigation zones it plans to monitor, the Navy should supplement its visual monitoring efforts with other monitoring measures including passive acoustic monitoring.

The commenter suggested that sonobuoys could be deployed with the target in the various target areas prior to the activity. This approach would allow the Navy to better determine whether the target area is clear and remains clear until the munition is launched.

Although the Navy indicated that it was continuing to improve its capabilities for using range instrumentation to aid in the passive acoustic detection of marine mammals, it also stated that it didn't have the capability or resources to monitor instrumented ranges in real time for the purpose of mitigation. That capability clearly exists. While available resources could be a limiting factor, the commenter notes that personnel who monitor the hydrophones on the operational side do have the ability to monitor for marine mammals as well. The commenter has supported the use of the instrumented ranges to fulfill mitigation implementation for quite some time (see the commenter's most recent November 13, 2017 letter) and contends that localizing certain species (or genera) provides more effective mitigation than localizing none at all.

The commenter recommended that NMFS require the Navy to use passive and active acoustic monitoring, whenever practicable, to supplement visual monitoring during the implementation of its mitigation measures for all activities that have the potential to cause injury or mortality beyond those explosive activities for which passive acoustic monitoring already was proposed, including those activities that would occur on the SCORE and PMRF ranges.

Response: For explosive mitigation zones, any additional increases in mitigation zone size (beyond what is depicted for each explosive activity) or observation requirements would be impracticable to implement due to implications for safety, sustainability, and the Navy's ability to meet Title 10 requirements to successfully accomplish military readiness objectives. We do note, however, that since the proposed rule, the Navy has committed to implementing pre-event observations for all in-water explosives events (including some that were not previously monitored) and to using additional platforms if available in the vicinity of the detonation area to help with this monitoring.

As discussed in the comment, the Navy does employ passive acoustic monitoring when practicable to do so (i.e., when assets that have passive acoustic monitoring capabilities are already participating in the activity). For other explosive events, there are no platforms participating that have passive acoustic monitoring capabilities. Adding a passive acoustic monitoring capability (either by adding a passive acoustic monitoring device to a platform already participating in the activity, or by adding a platform with integrated passive acoustic monitoring capabilities to the activity, such as a sonobuoy) for mitigation is not practicable. As discussed in Section 5.5.3 (Active and Passive Acoustic Monitoring Devices) of the HSTT FEIS/OEIS, there are significant manpower and logistical constraints that make constructing and maintaining additional passive acoustic monitoring systems or platforms for each training and testing activity impracticable. Additionally, diverting platforms that have passive acoustic monitoring platforms would impact their ability to meet their Title 10 requirements and reduce the service life of those systems.

Regarding the use of instrumented ranges for realtime mitigation, the commenter is correct that the Navy continues to develop the technology and capabilities on its Ranges for use in marine mammal monitoring, which can be effectively compared to operational information after the fact to gain information regarding marine mammal response. However, as discussed above, the manpower and logistical complexity involved in detecting and localizing marine mammals in relation to multiple fast-moving sound source platforms in order to implement real-time mitigation is significant. A more detailed discussion of the limitations for on range passive acoustic detection as real-time mitigation is provided in Comment 34 and is impracticable for the Navy. The Navy's instrumented ranges were not developed for the purpose of mitigation. For example, beaked whales produce highly directed echolocation clicks that are difficult to simultaneously detect on multiple hydrophones within the instrumented range at PMRF; therefore, there is a high probability that a vocalizing animal would be assigned a false location on the range (i.e., the Navy would not be able to verify its presence in a mitigation zone). Although the Navy is continuing to improve its capabilities to use range instrumentation to aid in the passive acoustic detection of marine mammals, at this time it would not be effective or practicable for the Navy to monitor instrumented ranges for the purpose of real-time mitigation for the reasons discussed in Section 5.5.3 (Active and Passive Acoustic Monitoring Devices) of the HSTT FEIS/OEIS.

Comment 28: The commenter recommended that NMFS require the Navy to conduct additional pre-activity overflights before conducting any activities involving detonations barring any safety issues (e.g., low fuel), as well as post-activity monitoring for activities involving medium- and large caliber projectiles, missiles, rockets, and bombs.

Response: The Navy has agreed to implement pre-event observation mitigation, as well as post-event observation, for all in-water explosive event mitigation measures. If there are other platforms participating in these events and in the vicinity of the detonation area, they will also visually observe this area as part of the mitigation team.

Comment 29: One commenter recommended that the Navy implement larger shutdown zones.

Response: The Navy mitigation zones represent the maximum surface area the Navy can effectively observe based on the platform involved, number of personnel that will be involved, and the number and type of assets and resources available. As mitigation zone sizes increase, the potential for observing marine mammals and thus reducing impacts decreases, because the number of observers can't increase although the area to observe increases. For instance, if a mitigation zone increases from 1,000 to 2,000 yd., the area that must be observed increases five-fold. NMFS has Start Printed Page 66886analyzed the Navy's required mitigation and found that it will effect the least practicable adverse impact. The Navy's mitigation measures consider both the need to reduce potential impacts and the ability to provide effective observations throughout a given mitigation zone. To implement these mitigation zones, Navy Lookouts are trained to use a combination of unaided eye and optics as they search the surface around a vessel. In addition, there are other Navy personnel on a given bridge watch (in addition to designated Lookouts), who are also constantly watching the water for safety of navigation and marine mammals. Takes that cannot be mitigated are analyzed and authorized provided the necessary findings can be made.

Comment 30: Commenters commented that NMFS should cap the maximum level of activities each year.

Response: The commenters offers no rationale for why a cap is needed and nor do they suggest what an appropriate cap might be. The Navy is responsible under Title 10 for conducting the needed amount of testing and training to maintain military readiness, which is what they have proposed and NMFS has analyzed. Further, the MMPA states that NMFS shall issue MMPA authorizations if the necessary findings can be made, as they have been here. Importantly, as described in the Mitigation Areas section, the Navy will limit activities (active sonar, explosive use, MTE exercises, etc.) to varying degrees in multiple areas that are important to sensitive species or for critical behaviors in order to minimize impacts that are more likely to lead to adverse effects on rates of recruitment or survival.

Comment 31: A commenter suggested the Navy could improve observer effectiveness through the use of NMFS-certified marine mammal observers.

Response: The Navy currently requires at least one qualified Lookout on watch at all times a vessel is underway. In addition, on surface ships with hull-mounted sonars during sonar events, the number increases with two additional Lookouts on the forward portion of the vessel (i.e., total of three Lookouts). Furthermore, unlike civilian commercial ships, there are additional bridge watch standers on Navy ships viewing the water during all activities. The Navy's Marine Species Awareness training that all bridge watchstanders including Lookouts take has been reviewed and approved by NMFS. This training is conducted annually and prior to MTEs. Note, Navy visual monitoring from Lookouts and bridge watchstanders as well as unit-based passive acoustic detection is used when available and appropriate.

As we understand from the Navy, mandating NMFS-certified marine mammal observers on all ships would require setting up and administering a certification program, providing security clearance for certified people, ensuring that all platforms are furnished with these individuals, and housing these people on ships for extended times from weeks to months. This would be an extreme logistic burden on realistic training. The requirement for additional non-Navy observers would provide little additional benefit, especially at the near ship mitigation ranges for mid-frequency active sonars on surface ships (<1,000 yds), nor be significantly better than the current system developed by the Navy in consultation with NMFS.

The purpose of Navy Lookouts is to provide sighting information for other boats and vessels in the area, in-water debris, and other safety of navigation functions. During active sonar use, additional personnel are assigned for the duration of the sonar event. In addition, the other Navy personnel on a given bridge watch along with designated Lookouts are also constantly watching the water for safety of navigation and marine mammals.

Navy training and testing activities often occur simultaneously and in various regions throughout the HSTT Study Area, with underway time that could last for days or multiple weeks at a time. The pool of certified marine mammal observers across the U.S. West Coast is rather limited, with many already engaged in regional NMFS survey efforts. Relative to the number of dedicated MMOs that would be required to implement this condition, as of July 2018, there are approximately 22 sonar-equipped Navy ships (i.e., surface ships with hull-mounted active sonars) stationed in San Diego. Six additional vessels from the Pacific Northwest also transit to Southern California for training (28 ships times 2 observers per watch times 2 watches per day = minimum of 112 observers).

Senior Navy commands in the Pacific continuously reemphasize the importance of Lookout responsibilities to all ships. Further, the Navy has an ongoing study in which certified Navy civilian scientist observers embark periodically on Navy ships in support of a comparative Lookout effectiveness study. Results from this study will be used to make recommendations for further improvements to Lookout training.

Additionally, we note that the necessity to include trained NMFS-approved PSOs on Navy vessels, while adding little or no additional protective or data-gathering value, would be very expensive and those costs would need to be offset—most likely through reductions in the budget for Navy monitoring, through which invaluable data is gathered.

Comment 32: Commenters commented that NMFS should consider increasing the exclusion zone to the 120 dB isopleth because some animals are sensitive to sonar at low levels of exposure.

Response: First, it is important to note that the Commenters are suggesting that NMFS require mitigation that would eliminate all take, which is not what the applicable standard requires. Rather, NMFS is required to put in place measures that effect the “least practicable adverse impact.” Separately, NMFS acknowledges that some marine mammals may respond to sound at 120 dB in some circumstances; however, based on the best available data, only a subset of those exposed at that low level respond in a manner that would be considered harassment under the MMPA. NMFS and the Navy have quantified those individuals of certain stocks where appropriate, analyzed the impacts, and authorized them where needed. Further, NMFS and the Navy have identified exclusion zone sizes that are best suited to minimize impacts to marine mammal species and stocks and their habitat while also being practicable (see Mitigation section).

Comment 33: A commenter commented that NMFS should impose a 10-kn ship speed in biologically important areas and critical habitat for marine mammals to reduce vessel strikes. One commenter also specifically referenced this measure in regard to humpback whales and blue whales.

Response: This issue also is addressed elsewhere in the Comments and Responses section for specific mitigation areas. However, generally speaking, it is impracticable (because of impacts to mission effectiveness) to further reduce ship speeds for Navy activities, and, moreover, given the maneuverability of Navy ships at higher speeds and the presence of effective Lookouts, any further reduction in speed would reduce the already low probability of ship strike little, if any. The Navy is unable to impose a 10-kn ship speed limit because it would not be practical to implement and would impact the effectiveness of Navy's activities by putting constraints on training, testing, and scheduling. The Navy requires flexibility in use of variable ship speeds for training, testing, operational, safety, and engineering qualification requirements. Navy ships Start Printed Page 66887typically use the lowest speed practical given individual mission needs. NMFS has reviewed the Navy's analysis of these additional restrictions and the impacts they would have on military readiness and concurs with the Navy's assessment that they are impracticable.

The main driver for ship speed reduction is reducing the possibility and severity of ship strikes to large whales. However, even given the wide ranges of speeds from slow to fast that Navy ships must use to meet training and testing requirements, the Navy has a very low strike history to large whales in Southern California, with no whales struck by the Navy from 2010-2018. Current Navy Standard Operating Procedures and mitigations require a minimum of at least one Lookout on duty while underway (in addition to bridge watch personnel) and, so long as safety of navigation is maintained, to keep 500 yards away from large whales and 200 yards away from other marine mammals (except for bow-riding dolphins and pinnipeds hauled out on shore or structures). Furthermore, there is no Navy ship strike of a marine mammal on record in SOCAL that has occurred in the coastal area (~40 Nmi from shore), which is where speed restrictions are most requested. Finally, the most recent model estimate of the potential for civilian ship strike risk to blue, humpback, and fin whales off the coast of California found the highest risk near San Francisco and Long Beach associated with commercial ship routes to and from those ports (Rockwood et al., 2018). There was no indication of a similar high risk to these species off San Diego, where the HSTT Study Area occurs.

Previously, the Navy commissioned a vessel density and speed report based on an analysis of Navy ship traffic in the HSTT Study Area between 2011 and 2015. Median speed of all Navy vessels within the HSTT Study Area is typically already low, with median speeds between 5 and 12 knots. Further, the presence and transits of commercial and recreational vessels, annually numbering in the thousands, poses a more significant risk to large whales than the presence of Navy vessels. The HSTT FEIS/OEIS Chapter 3 (Affected Environment and Environmental Consequences) Section 3.7.3.4.1 (Impacts from Vessels and In-Water Devices) and Appendix K, Section K.4.1.6.2 (San Diego (Arc) Blue Whale Feeding Area Mitigation Considerations), explain the important differences between most Navy vessels and their operation and commercial ships that make Navy vessels much less likely to strike a whale.

When developing Phase III mitigation measures, the Navy analyzed the potential for implementing additional types of mitigation, such as vessel speed restrictions within the HSTT Study Area. The Navy determined that based on how the training and testing activities will be conducted within the HSTT Study Area, vessel speed restrictions would be incompatible with practicability criteria for safety, sustainability, and training and testing missions, as described in Chapter 5 (Mitigation), Section 5.3.4.1 (Vessel Movement) of the HSTT FEIS/OEIS.

Comment 34: Commenters commented that NMFS should improve detection of marine mammals with restrictions on low-visibility activities and alternative detection such as thermal or acoustic methods.

Response: The Navy has compiled information related to the effectiveness of certain equipment to detect marine mammals in the context of their activities, as well as the practicality and effect on mission effectiveness of using various equipment. NMFS has reviewed this evaluation and concurs with the characterization and the conclusions below.

Low visibility—Anti-submarine warfare training involving the use of mid-frequency active sonar typically involves the periodic use of active sonar to develop the “tactical picture,” or an understanding of the battle space (e.g., area searched or unsearched, presence of false contacts, and an understanding of the water conditions). Developing the tactical picture can take several hours or days, and typically occurs over vast waters with varying environmental and oceanographic conditions. Training during both high visibility (e.g., daylight, favorable weather conditions) and low visibility (e.g., nighttime, inclement weather conditions) is vital because sonar operators must be able to understand the environmental differences between day and night and varying weather conditions and how they affect sound propagation and the detection capabilities of sonar. Temperature layers move up and down in the water column and ambient noise levels can vary significantly between night and day, affecting sound propagation and how sonar systems are operated. Reducing or securing power in low-visibility conditions as a mitigation would affect a commander's ability to develop the tactical picture and would prevent sonar operators from training in realistic conditions. Further, during integrated training multiple vessels and aircraft may participate in an exercise using different dimensions of warfare simultaneously (e.g., submarine warfare, surface warfare, air warfare, etc.). If one of these training elements were adversely impacted (e.g., if sonar training reflecting military operations were not possible), the training value of other integrated elements would also be degraded. Additionally, failure to test such systems in realistic military operational scenarios increases the likelihood these systems could fail during military operations, thus unacceptably placing Sailors' lives and the Nation's security at risk. Some systems have a nighttime testing requirement; therefore, these tests cannot occur only in daylight hours. Reducing or securing power in low visibility conditions would decrease the Navy's ability to determine whether systems are operationally effective, suitable, survivable, and safe for their intended use by the fleet even in reduced visibility or difficult weather conditions.

Thermal detection—Thermal detection systems are more useful for detecting marine mammals in some marine environments than others. Current technologies have limitations regarding water temperature and survey conditions (e.g., rain, fog, sea state, glare, ambient brightness), for which further effectiveness studies are required. Thermal detection systems are generally thought to be most effective in cold environments, which have a large temperature differential between an animal's temperature and the environment. Current thermal detection systems have proven more effective at detecting large whale blows than the bodies of small animals, particularly at a distance. The effectiveness of current technologies has not been demonstrated for small marine mammals. Thermal detection systems exhibit varying degrees of false positive detections (i.e., incorrect notifications) due in part to their low sensor resolution and reduced performance in certain environmental conditions. False positive detections may incorrectly identify other features (e.g., birds, waves, boats) as marine mammals. In one study, a false positive rate approaching one incorrect notification per 4 min. of observation was noted.

The Navy has been investigating the use of thermal detection systems with automated marine mammal detection algorithms for future mitigation during training and testing, including on autonomous platforms. Thermal detection technology being researched by the Navy, which is largely based on existing foreign military grade hardware, is designed to allow observers and eventually automated software to detect the difference in temperature Start Printed Page 66888between a surfaced marine mammal (i.e., the body or blow of a whale) and the environment (i.e., the water and air). Although thermal detection may be reliable in some applications and environments, the current technologies are limited by their: (1) Low sensor resolution and a narrow fields of view, (2) reduced performance in certain environmental conditions, (3) inability to detect certain animal characteristics and behaviors, and (4) high cost and uncertain long term reliability.

Thermal detection systems for military applications are deployed on various Department of Defense (DoD) platforms. These systems were initially developed for night time targeting and object detection such as a boat, vehicle, or people. Existing specialized DoD infrared/thermal capabilities on Navy aircraft and surface ships are designed for fine-scale targeting. Viewing arcs of these thermal systems are narrow and focused on a target area. Furthermore, sensors are typically used only in select training events, not optimized for marine mammal detection, and have a limited lifespan before requiring expensive replacement. Some sensor elements can cost upward of $300,000 to $500,000 per device, so their use is predicated on a distinct military need.

One example of trying to use existing DoD thermal system is being proposed by the U.S. Air Force. The Air Force agreed to attempt to use specialized U.S. Air Force aircraft with military thermal detection systems for marine mammal detection and mitigation during a limited at-sea testing event. It should be noted, however, these systems are specifically designed for and integrated into a small number of U.S. Air Force aircraft and cannot be added or effectively transferred universally to Navy aircraft. The effectiveness remains unknown in using a standard DoD thermal system for the detection of marine mammals without the addition of customized system-specific computer software to provide critical reliability (enhanced detection, cueing for an operator, reduced false positive, etc.)

Finally, current DoD thermal sensors are not always optimized for marine mammal detections verse object detection, nor do these systems have the automated marine mammal detection algorithms the Navy is testing via its ongoing research program. The combination of thermal technology and automated algorithms are still undergoing demonstration and validation under Navy funding.

Thermal detection systems specifically for marine mammal detection have not been sufficiently studied both in terms of their effectiveness within the environmental conditions found in the HSTT Study Area and their compatibility with Navy training and testing (i.e., polar waters vs. temperate waters). The effectiveness of even the most advanced thermal detection systems with technological designs specific to marine mammal surveys is highly dependent on environmental conditions, animal characteristics, and animal behaviors. At this time, thermal detection systems have not been proven to be more effective than, or equally effective as, traditional techniques currently employed by the Navy to observe for marine mammals (i.e., naked-eye scanning, hand-held binoculars, high-powered binoculars mounted on a ship deck). The use of thermal detection systems instead of traditional techniques would compromise the Navy's ability to observe for marine mammals within its mitigation zones in the range of environmental conditions found throughout the Study Area. Furthermore, thermal detection systems are designed to detect marine mammals and do not have the capability to detect other resources for which the Navy is required to implement mitigation, including sea turtles. Focusing on thermal detection systems could also provide a distraction from and compromise to the Navy's ability to implement its established observation and mitigation requirements. The mitigation measures discussed in Chapter 5 (Mitigation), Section 5.3 (Procedural Mitigation to be Implemented) of the HSTT FEIS/OEIS include the maximum number of Lookouts the Navy can assign to each activity based on available manpower and resources; therefore, it would be impractical to add personnel to serve as additional Lookouts. For example, the Navy does not have available manpower to add Lookouts to use thermal detection systems in tandem with existing Lookouts who are using traditional observation techniques.

The Defense Advanced Research Projects Agency funded six initial studies to test and evaluate infrared-based thermal detection technologies and algorithms to automatically detect marine mammals on an unmanned surface vehicle. Based on the outcome of these initial studies, follow-on efforts and testing are planned for 2018-2019. The Office of Naval Research Marine Mammals and Biology program funded a project (2013-2018) to test the thermal limits of infrared-based automatic whale detection technology. This project is focused on capturing whale spouts at two different locations featuring subtropical and tropical water temperatures, optimizing detector/classifier performance on the collected data, and testing system performance by comparing system detections with concurrent visual observations.

The Office of Naval Research Marine Mammals and Biology program is currently funding an ongoing project (2013-2018) that is testing the thermal limits of infrared based automatic whale detection technology (Principal Investigators: Olaf Boebel and Daniel Zitterbart). This project is focused on (1) capturing whale spouts at two different locations featuring subtropical and tropical water temperatures; (2) optimizing detector/classifier performance on the collected data; and (3) testing system performance by comparing system detections with concurrent visual observations. In addition, Defense Advanced Research Projects Agency (DARPA) has funded six initial studies to test and evaluate current technologies and algorithms to automatically detect marine mammals (IR thermal detection being one of the technologies) on an unmanned surface vehicle. Based on the outcome of these initial studies, follow-on efforts and testing are planned for 2018-2019.

The Navy plans to continue researching thermal detection systems for marine mammal detection to determine their effectiveness and compatibility with Navy applications. If the technology matures to the state where thermal detection is determined to be an effective mitigation tool during training and testing, NMFS and the Navy will assess the practicability of using the technology during training and testing events and retrofitting the Navy's observation platforms with thermal detection devices. The assessment will include an evaluation of the budget and acquisition process (including costs associated with designing, building, installing, maintaining, and manning the equipment); logistical and physical considerations for device installment, repair, and replacement (e.g., conducting engineering studies to ensure there is no electronic or power interference with existing shipboard systems); manpower and resource considerations for training personnel to effectively operate the equipment; and considerations of potential security and classification issues. New system integration on Navy assets can entail up to 5 to 10 years of effort to account for acquisition, engineering studies, and development and execution of systems training. The Navy will provide information to NMFS about the status and findings of Navy-funded thermal Start Printed Page 66889detection studies and any associated practicability assessments at the annual adaptive management meetings.

Passive Acoustic Monitoring—The Navy does employ passive acoustic monitoring when practicable to do so (i.e., when assets that have passive acoustic monitoring capabilities are already participating in the activity). For other explosive events, there are no platforms participating that have passive acoustic monitoring capabilities. Adding a passive acoustic monitoring capability (either by adding a passive acoustic monitoring device to a platform already participating in the activity, or by adding a platform with integrated passive acoustic monitoring capabilities to the activity, such as a sonobuoy) for mitigation is not practicable. As discussed in Chapter 5 (Mitigation), Section 5.5.3 (Active and Passive Acoustic Monitoring Devices) of the HSTT FEIS/OEIS, there are significant manpower and logistical constraints that make constructing and maintaining additional passive acoustic monitoring systems or platforms for each training and testing activity impracticable. Additionally, diverting platforms that have passive acoustic monitoring platforms would impact their ability to meet their Title 10 requirements and reduce the service life of those systems.

The use of real-time passive acoustic monitoring (PAM) for mitigation at the Southern California Anti-submarine Warfare Range (SOAR) exceeds the capability of current technology. The Navy has a significant research investment in the Marine Mammal Monitoring on Navy Ranges (M3R) system at three ocean locations including SOAR. However, this system was designed and intended to support marine mammal research for select species, and not as a mitigation tool. Marine mammal PAM using instrumented hydrophones is still under development and while it has produced meaningful results for marine species monitoring, abundance estimation, and research, it was not developed for nor is it appropriate for real-time mitigation. The ability to detect, classify, and develop an estimated position (and the associated area of uncertainty) differs across species, behavioral context, animal location vs. receiver geometry, source level, etc. Based on current capabilities, and given adequate time, vocalizing animals within an indeterminate radius around a particular hydrophone are detected, but obtaining an estimated position for all individual animals passing through a predetermined area is not assured. Detecting vocalizations on a hydrophone does not determine whether vocalizing individuals would be within the established mitigation zone in the timeframes required for mitigation. Since detection ranges are generally larger than current mitigation zones for many activities, this would unnecessarily delay events due to uncertainty in the animal's location and put at risk event realism.

Furthermore, PAM at SOAR does not account for animals not vocalizing. For instance, there have been many documented occurrences during PAM verification testing at SOAR of small boats on the water coming across marine mammals such as baleen whales that were not vocalizing and therefore not detected by the range hydrophones. Animals must vocalize to be detected by PAM; the lack of detections on a hydrophone may give the false impression that the area is clear of marine mammals. The lack of vocalization detections is not a direct measure of the absence of marine mammals. If an event were to be moved based upon low-confidence localizations, it may inadvertently be moved to an area where non-vocalizing animals of undetermined species are present.

To develop an estimated position for an individual, it must be vocalizing and its vocalizations must be detected on at least three hydrophones. The hydrophones must have the required bandwidth, and dynamic range to capture the signal. In addition, calls must be sufficiently loud so as to provide the required signal to noise ratio on the surrounding hydrophones. Typically, small odontocetes echolocate with a directed beam that makes detection of the call on multiple hydrophones difficult. Developing an estimated position of selected species requires the presence of whistles which may or may not be produced depending on the behavioral state. Beaked whales at SOAR vocalize only during deep foraging dives which occur at a rate of approximately 10 per day. They produce highly directed echolocation clicks that are difficult to simultaneously detect on multiple hydrophones. Current real-time systems cannot follow individuals and at best produce sparse positions with multiple false locations. The position estimation process must occur in an area with hydrophones spaced to allow the detection of the same echolocation click on at least three hydrophones. Typically, a spacing of less than 4 km in water depths of approximately 2 km is preferred. In the absence of detection, the analyst can only determine with confidence if a group of beaked whales is somewhere within 6 km of a hydrophone. Beaked whales produce stereotypic click trains during deep (<500 m) foraging dives. The presence of a vocalizing group can be readily detected by an analyst by examining the click structure and repetition rate. However, estimating position is possible only if the same train of clicks is detected on multiple hydrophones which is often precluded by the animal's narrow beam pattern. Currently, this is not an automated routine.

In summary, the analytical and technical capabilities required to use PAM such as M3R at SOAR as a required mitigation tool are not sufficiently robust to rely upon due to limitations with near real-time classification and determining estimated positions. The level of uncertainty as to a species presence or absence and location are too high to provide the accuracy required for real-time mitigation. As discussed in Chapter 5 (Mitigation) of the HSTT FEIS/OEIS, existing Navy visual mitigation procedures and measures, when performed by individual units at-sea, still remain the most practical means of protection for marine species.

Comment 35: Commenters commented that NMFS should add mitigation for other marine mammal stressors such as dipping sonar, pile driving, and multiple exposures near homeports.

Response: The Navy implements a 200-yd shutdown for dipping sonar and a 100-yd exclusion zone for pile-driving. It is unclear what the commenter means by adding mitigation for “multiple exposures” near homeports, and therefore no explanation can be provided.

Mitigation Areas

Introduction

The Navy included a comprehensive proposal of mitigation measures in their initial application that included procedural mitigations that reduce the likelihood of mortality, injury, hearing impairment, and more severe behavioral responses for most species. The Navy also included time/area mitigation that further protects areas where important behaviors are conducted and/or sensitive species congregate, which reduces the likelihood of takes that are likely to impact reproduction or survival (as described in the Mitigation Measures section of the final rule and the Navy's application). As a general matter, where an applicant proposes measures that are likely to reduce impacts to marine mammals, the fact that they are included in the proposal Start Printed Page 66890and application indicates that the measures are practicable, and it is not necessary for NMFS to conduct a detailed analysis of the measures the applicant proposed (rather, they are simply included). However, it is necessary for NMFS to consider whether there are additional practicable measures that could also contribute to the reduction of adverse effects on the species or stocks through effects on annual rates of recruitment or survival. In the case of the Navy's HSTT application, we worked with the Navy prior to the publication of the proposed rule and ultimately the Navy agreed to increase geographic mitigation areas adjacent to the island of Hawaii to more fully encompass specific biologically important areas and the Alenuihaha Channel and to limit additional anti-submarine warfare mid-frequency active sonar (ASW) source bins (MF4) within some geographic mitigation areas.

During the public comment period on the proposed rule, NMFS received numerous recommendations for the Navy to implement additional mitigation measures, both procedural and time/area limitations. Extensive discussion of the recommended mitigation measures in the context of the factors considered in the least practicable adverse impact analysis (considered in the Mitigation Measures section of the final rule and described below), as well as considerations of alternate iterations or portions of the recommended measures considered to better address practicability concerns, resulted in the addition of several procedural mitigations and expansion of multiple time/area mitigations (see the Mitigation Measures section in the final rule). These additional areas reflect, for example, concerns about blue whales in SOCAL and small resident odontocete populations in Hawaii (which resulted in expanded time/area mitigation), focus on areas where important behaviors and habitat are found (e.g., in BIAs), and enhancement of the Navy's ability to detect and reduce injury and mortality (which resulted in expanded monitoring before and after explosive events). Through extensive discussion, NMFS and the Navy worked to identify and prioritize additional mitigation measures that are likely to reduce impacts on marine mammal species or stocks and their habitat and are also possible for the Navy to implement.

Following the publication of the 2013 HSTT MMPA incidental take rule, the Navy (and NMFS) were sued and the resulting settlement agreement prohibited or restricted Navy activities within specific areas in the HSTT Study Area. These provisional prohibitions and restrictions on activities within the HSTT Study Area were derived pursuant to negotiations with the plaintiffs in that lawsuit were specifically not evaluated or selected based on the type of thorough examination of best available science that occurs through the rulemaking process under the MMPA, or through related analyses conducted under the National Environmental Policy Act (NEPA) or the ESA. The agreement did not constitute a concession by the Navy as to the potential impacts of Navy activities on marine mammals or any other marine species, or to the practicability of the measures. The Navy's adoption of restrictions on its HSTT activities as part of a relatively short-term settlement does not mean that those restrictions are necessarily supported by the best available science, likely to reduce impacts to marine mammals species or stocks and their habitat, or practicable to implement from a military readiness standpoint over the longer term in the HSTT Study Area. Accordingly, as required by statute, NMFS analyzed the Navy's activities, impacts, mitigation and potential mitigation (including the settlement agreement measures) pursuant to the “least practicable adverse impact” standard to determine the appropriate mitigation to include in these regulations. Some of the measures included in the settlement agreement are included in the final rule, while some are not. Other measures that were not included in the settlement agreement are included in the final rule.

Ultimately, the Navy adopted all mitigation measures that are practicable without jeopardizing its mission and Title 10 responsibilities. In other words, a comprehensive assessment by Navy leadership of the final, entire list of mitigation measures concluded that the inclusion of any further mitigation beyond those measures identified here in the final rule would be entirely impracticable. NMFS independently reviewed the Navy's practicability determinations for specific mitigation areas and concurs with the Navy's analysis.

As we outlined in the Mitigation Measures section, NMFS has reviewed Appendix K (Geographic Mitigation Assessment) in the Navy's HSTT FEIS/OEIS and information contained reflects the best available science as well as a robust evaluation of the practicability of different measures, and NMFS uses Appendix K to support our independent least practicable adverse impact analysis. Below is additional discussion regarding specific recommendations for mitigation measures.

Comment 36: With respect to the national security exemption related to mitigation areas, a commenter recommended that NMFS should specify that authorization may be given only by high-level officers, consistent with the Settlement Agreement or with previous HSTT rulings.

Response: The Navy provided the technical analyses contained in Appendix K (Geographic Mitigation Assessment) of the HSTT FEIS/OEIS that included details regarding changing the measure to the appropriate delegated Command designee (see specifically Appendix K, Section K.2.2.1 (Proposed Mitigation Areas within the HSTT Study Area), for each of the proposed areas). The commenter proposed “authorization may be given only by high-level officers” and therefore appears to have missed the designations made within the cited sections above since those do constitute positions that could only be considered “high level officers.” The decision would be delegated to high-level officers. This delegation has been clarified in the Final rule as “permission from the appropriate designated Command authority.”

SOCAL Areas

Comment 37: NPS recommended that the Navy consider the following as it plans to conduct activities in the HSTT Study Area. NPS noted the units of the NPS system that occur near the Navy's training and testing locations in Southern California and which may be affected by noise including Channel Islands National Park (NP) and Cabrillo National Monument.

Response: National Parks and marine protected areas in are addressed in Chapter 6 of the HSTT FEIS/OEIS. The Channel Islands National Marine Sanctuary consists of an area of 1,109 nmi2 around Anacapa Island, Santa Cruz Island, Santa Rosa Island, San Miguel Island and Santa Barbara Island to the south. Only 92 nmi2 of Santa Barbara Island, or about 8 percent of the Channel Island National Marine Sanctuary, occurs within the SOCAL portion of the HSTT Study Area, but the entirety of that piece is included in the Santa Barbara Mitigation Area. The Navy will continue to implement a mitigation area out to 6 nmi of Santa Barbara Island, which includes a portion of the Channel Island National Marine Sanctuary and the Santa Barbara Marine Protected Area where the Navy will restrict the use of MF1 sonar sources and some explosive during training. Please refer to Figure 5.4-4 in the Navy's HSTT FEIS/OEIS shows the Start Printed Page 66891spatial extent of the Santa Barbara Island mitigation area.

Cabrillo National Monument only contains some intertidal areas, but no marine waters. No Navy activities overlap with the Cabrillo National Monument; therefore, no impacts are expected.

Comment 38: A commenter recommended to extend the seasonality of the San Diego Arc Mitigation Area to December 31 for blue whales are present off southern California almost year round, and relatively higher levels from June 1 through December 31.

Response: Analysis of the San Diego Arc Mitigation Area and its consideration for additional geographic mitigation is provided in the HSTT FEIS/OEIS in Appendix K (Geographic Mitigation Assessment), Section K.4.1.6 (San Diego (Arc) Blue Whale Feeding Area; Settlement Areas 3-A through 3-C, California Coastal Commission 3 nmi Shore Area, and San Diego Arc Area), Section K.5.5 (Settlement Areas within the Southern California Portion of the HSTT Study Area), and Section K.6.2 (San Diego Arc: Area Parallel to the Coastline from the Gulf of California Border to just North of Del Mar). This analysis included consideration of seasonality and the potential effectiveness of restrictions to use of mid-frequency active sonar by Navy in the area. Based on the Appendix K (Geographic Mitigation Assessment) analyses, the Navy will implement additional mitigation within the San Diego Arc Mitigation Area, as detailed in Chapter 5 (Mitigation) Section 5.4.3 (Mitigation Areas for Marine Mammals in the Southern California Portion of the Study Area) of the HSTT FEIS/OEIS, to further avoid or reduce impacts on marine mammals from acoustic and explosive stressors and vessel strikes from Navy training and testing in this location. Since the proposed rule, the Navy is now limiting MF1 surface ship hull-mounted MFAS even further in the San Diego Arc Mitigation Area. The Navy will not conduct more than 200 hrs of MF1 MFAS in the combined areas of the San Diego Arc Mitigation Area and newly added San Nicholas Island and Santa Monica/Long Beach Mitigation Areas. As described in the proposed rule, the Navy will not use explosives that could potentially result in the take of marine mammals during large-caliber gunnery, torpedo, bombing, and missile (including 2.75″ rockets) activities during training and testing in the San Diego Mitigation Area. Regarding the recommended increase in seasonality to December 31, the San Diego Arc and current seasonality is based on the Biologically Important Area associated with this mitigation area (Calambokidis et al., 2017), which identifies the primary months for feeding. While blue whale calls have been detected in Southern California through December (Rice et al., 2017, Lewis and Širović, in press), given a large propagation range (10-50 km or more) for low-frequency blue whale vocalization, blue whale call detection from a Navy-funded single passive acoustic device near the San Diego Arc may not be a direct correlation with blue whale presence within the San Diego Arc from November through December. In addition, passive acoustic call detection data does not currently allow for direct abundance estimates. Calls may indicate some level of blue whale presence, but not abundance or individual residency time. In the most recent Navy-funded passive acoustic monitoring report including the one site in the northern San Diego Arc from June 2015 to April 2016, blue whale call detection frequency near the San Diego Arc starts declining in November after an October peak (Rice et al., 2017, Širović, personal communication). The newest Navy-funded research on blue whale movements from 2014 to 2017 along the U.S. West Coast based on satellite tagging, has shown that individual blue whale movement is wide ranging with large distances covered daily (Mate et al., 2017). Nineteen (19) blue whales were tagged in 2016, the most recent reporting year available (Mate et al., 2017). Only 5 of the 19 blue whales spent time in the SOCAL portion of the HSTT Study Area, and only spent a few days within the range complex (2-13 days). Average distance from shore for blue whales was 113 km. None of the 19 blue whales tagged in 2016 spent time within the San Diego Arc. From previous year efforts (2014-2015), only a few tagged blue whales passed through the San Diego Arc. In addition, Navy and non-Navy-funded blue whale satellite tagging studies started in the early 1990s and has continued irregularly through 2017. In general, most blue whales start a south-bound migration from the “summer foraging areas” in the mid- to late-fall time period, unless food has not been plentiful, which can lead to a much earlier migration south. Therefore, while blue whales have been documented within the San Diego Arc previously, individual use of the area is variable, likely of short duration, and declining after October. Considering the newest passive acoustic and satellite tagging data, there is no scientific justification for extending the San Diego Arc Mitigation Area period from October 31 to December 31.

Comment 39: A commenter recommended limiting all MF1 use within the San Diego Arc Mitigation Area. A commenter also recommended NMFS should carefully consider prohibiting use of other LFAS and MFAS during the time period the San Diego Arc Mitigation Areas is in place, and for the MTEs to be planned for other months of the year.

Response: Since the proposed rule, the Navy is now limiting MF1 surface ship hull-mounted MFAS even further in the San Diego Arc Mitigation Area. The Navy will not conduct more than 200 hrs of MF1 MFAS in the combined areas of the San Diego Arc Mitigation Area and newly added San Nicholas Island and Santa Monica/Long Beach Mitigation Areas. Appendix K (Geographic Mitigation Assessment) of the HSTT FEIS/OEIS discusses the Navy's analysis of MFAS restrictions within the San Diego Arc Mitigation Area. Other training MFAS systems are likely to be used less frequently in the vicinity of the San Diego Arc area than surface ship MFAS. Given water depths, the San Diego Arc area is not conducive for large scale anti-submarine warfare exercises, nor near areas where other anti-submarine warfare training and testing occurs. Due to the presence of existing Navy subareas in the southern part of the San Diego Arc, a limited amount of helicopter dipping MFAS could occur. These designated range areas are required for proximity to airfields in San Diego such as Naval Air Station North Island and for airspace management. However, helicopters only used these areas in the Arc for a Kilo Dip. A Kilo Dip is a functional check of approximately 1-2 pings of active sonar to confirm the system is operational before the helicopter heads to more remote offshore training areas. This ensures proper system operation and avoids loss of limited training time, expenditure of fuel, and cumulative engine use in the event of equipment malfunction. The potential effects of dipping sonar have been accounted for in the Navy's analysis. Dipping sonar is further discussed below in Comment 40.

Comment 40: A commenter recommended prohibiting the use of air-deployed mid-frequency active sonar in the San Diego Arc Mitigation Area.

Response: The HSTT FEIS/OEIS and specifically Appendix K (Geographic Mitigation Assessment) discuss the Navy's analysis of mid-frequency and low-frequency active sonar restrictions within the San Diego Arc. Other sonar systems are likely to be used less frequently in the vicinity of the San Start Printed Page 66892Diego Arc than surface ship mid-frequency active sonars. In regard to the recommendation to prohibit “air-deployed” or dipping mid-frequency active sonar, the only helicopter dipping sonar activity that would likely be conducted in the San Diego Arc area is a Kilo Dip, which occurs relatively infrequently and involves a functional check of approximately 1-2 pings of active sonar before moving offshore beyond the San Diego Arc to conduct the training activity. During use of this sonar, the Navy will implement the procedural mitigation as described in Section 5.3.2.1 (Active Sonar). The Kilo Dip functional check needs to occur close to Naval Air Station North Island in San Diego to insure all systems are functioning properly, before moving offshore. This ensures proper system operation and avoids loss of limited training time, expenditure of fuel, and cumulative engine use in the event of equipment malfunction. The potential effects of dipping sonar have been accounted for in the Navy's analysis. Further, due to lower power settings for dipping sonar, potential behavioral impact ranges of dipping sonar are significantly lower than surface ship sonars. For example, the HSTT average modeled range to temporary threshold shift of dipping sonar for a 1-second ping on low-frequency cetacean (i.e., blue whale) is 77 m (HSTT FEIS/OEIS Table 3.7-7). This range is easily monitored for large whales by a hovering helicopter and is accounted for in the Navy's proposed mitigation ranges for dipping sonars. Limited ping time and lower power settings therefore would limit the impact from dipping sonar to any marine mammal species. It should be pointed out that the commenter's recommendation is based on new Navy behavioral response research specific to beaked whales (Falcone et al., 2017). The Navy relied upon the best science that was available to develop behavioral response functions in consultation with NMFS for the HSTT FEIS/OEIS. The article cited in the comment (Falcone et al., 2017) was not available at the time the HSTT EIS/OEIS was published. The new information and data presented in the article was thoroughly reviewed when it became available and further considered in discussions with some of the paper's authors. Many of the variables requiring further analysis for beaked whales and dipping sonar impact assessment are still being researched under continued Navy funding through 2019. The small portion of designated Kilo Dip areas that overlap the southern part of the San Diego Arc is not of sufficient depth for preferred habitat of beaked whales (see Figure 2.1-9 in the HSTT FEIS/OEIS). Further, passive acoustic monitoring for the past several years in the San Diego Arc confirms a lack of beaked whale detections (Rice et al., 2017). Also, behavioral responses of beaked whales from dipping and other sonars cannot be universally applied to other species including blue whales. Navy-funded behavioral response studies of blue whales to simulated surface ship sonar has demonstrated there are distinct individual variations as well as strong behavioral state considerations that influence any response or lack of response (Goldbogen et al., 2013).

Comment 41: A commenter recommends requiring vessel speed restrictions within the San Diego Arc Mitigation Area.

Response: Previously, the Navy commissioned a vessel density and speed report for the HSTT Study Area (CNA, 2016). Based on an analysis of Navy ship traffic in the HSTT Study Area between 2011 and 2015, median speed of all Navy vessels within Southern California is typically already low, with median speeds between 5 and 12 kn (CAN, 2016). Slowest speeds occurred closer to the coast including the general area of the San Diego Arc and approaches to San Diego Bay. The presence and transits of commercial and recreational vessels, numbering in the many hundreds, far outweighs the presence of Navy vessels. According the the SARs, blue whale mortality and injuries attributed to commercial ship strikes in California waters was zero in the most recent reporting period between 2011 and 2015 (Carretta et al., 2017a). However, ship strikes were implicated in the deaths of four blue whales and the serious injury of a fifth whale between 2009 and 2013 (Carretta et al., 2015). There has been no confirmed Navy ship strike to a blue whale in the entire Pacific over the 13-year period from 2005 to 2017. To minimize the possibility of ship strike in the San Diego Arc Mitigation Area, the Navy will implement procedural mitigation for vessel movements based on guidance from NMFS for vessel strike avoidance. The Navy will also issue seasonal awareness notification messages to all Navy vessel of blue, fin, and gray whale occurrence to increase ships awareness of marine mammal presence as a means of improving detection and avoidance of whales in SOCAL. When developing the mitigation for this 2018-2023 rule, the Navy analyzed the potential for implementing additional types of mitigation, such as developing vessel speed restrictions within the HSTT Study Area. The Navy determined that based on how the training and testing activities will be conducted within the HSTT Study Area under the planned activities, vessel speed restrictions would be incompatible with the practicability assessment criteria for safety, sustainability, and Title 10 requirements, as described in Section 5.3.4.1 (Vessel Movement) of the HSTT FEIS/OEIS.

Comment 42: A commenter recommended prohibiting the use of air-deployed mid-frequency active sonar in the Santa Barbara Island Mitigation Area.

Response: The commenter requested to prohibit “air-deployed” mid-frequency active sonar is based on one paper (Falcone et al., 2017), which is a Navy-funded project designed to study behavioral responses of a single species, Cuvier's beaked whales, to mid-frequency active sonar. The Navy relied upon the best science that was available to develop behavioral response functions for beaked whales and other marine mammals in consultation with NMFS for the HSTT FEIS/OEIS. The article cited in the comment (Falcone et al., 2017) was not available at the time the HSTT DEIS/OEIS was published but does not change the HSTT FEIS/OEIS criteria or conclusions. The new information and data presented in the article were thoroughly reviewed when they became available and further considered in discussions with some of the paper's authors. Many of the variables requiring further analysis for beaked whales and dipping sonar impact assessment are still being researched under continued Navy funding through 2019.

Behavioral responses of beaked whales from dipping and other sonars cannot be universally applied to other marine mammal species. For example, Navy-funded behavioral response studies of blue whales to simulated surface ship sonar has demonstrated there are distinct individual variations as well as strong behavioral state considerations that influence any response or lack of response (Goldbogen et al., 2013). The same conclusion on the importance of exposure and behavioral context was stressed by Harris et al. (2017). Therefore, it is expected that other species would also have highly variable individual responses ranging from some response to no response to any anthropogenic sound. This variability is accounted for in the Navy's current behavioral response curves described in the HSTT FEIS/OEIS and supporting technical reports.Start Printed Page 66893

The potential effects of dipping sonar have been rigorously accounted for in the Navy's analysis. Parameters such as power level and propagation range for typical dipping sonar use are factored into HSTT acoustic impact analysis along with guild specific criteria and other modeling variables as detailed in the HSTT FEIS/OEIS and associated technical reports for criteria and acoustic modeling. Due to lower power settings for dipping sonar, potential impact ranges of dipping sonar are significantly lower than surface ship sonars. For example, the HSTT average modeled range to temporary threshold shift of dipping sonar for a 1-second ping on low-frequency cetacean (i.e., blue whale) is 77 m, and for mid-frequency cetaceans including beaked whales is 22 m (HSTT FEIS/OEIS Table 3.7-7). This range is monitored for marine mammals by a hovering helicopter and is accounted for in the Navy's proposed mitigation ranges for dipping sonars (200 yd. or 183 m). Limited ping time and lower power settings therefore would limit the impact from dipping sonar to any marine mammal species.

For other marine mammal species, the small area around Santa Barbara Island does not have resident marine mammals, formally identified biologically important areas, nor is it identified as a breeding or persistent foraging location for cetaceans. Instead, the same marine mammals that range throughout the offshore Southern California area could pass at some point through the marine waters of Santa Barbara Island. As discussed in Appendix K (Geographic Mitigation Assessment) of the HSTT FEIS/OEIS, the Navy is already proposing year-round limitations to mid-frequency active sonar and larger explosive use. The Navy will not use MF1 surface ship hull-mounted mid-frequency active sonar during training or testing, or explosives that could potentially result in the take of marine mammals during medium-caliber or large-caliber gunnery, torpedo, bombing, and missile (including 2.75″ rockets) activities during training in the Santa Barbara Island Mitigation Area. Other mid-frequency active sonar systems for which the Navy is seeking authorization within SOCAL are used less frequently than surface ship sonars, and more importantly are of much lower power with correspondingly lower propagation ranges and reduced potential behavioral impacts.

Comment 43: A commenter recommended prohibiting other sources of mid-frequency active sonar in the Santa Barbara Mitigation Area.

Response: Appendix K (Geographic Mitigation Assessment) discusses the Navy's analysis of mid-frequency active sonar restrictions around Santa Barbara Island. Other training mid-frequency active sonar (MFAS) systems are likely to be used less frequently in the vicinity Santa Barbara Island than surface ship mid-frequency active sonars. Although not prohibiting the use of other sources of MFAS, the Navy will not use MF1 surface ship hull-mounted mid-frequency active sonar during training or testing, or explosives that could potentially result in the take of marine mammals during medium-caliber or large-caliber gunnery, torpedo, bombing, and missile (including 2.75″ rockets) activities during training in the Santa Barbara Island Mitigation Area.

Comment 44: A commenter recommended implementing vessel speed restrictions in the Santa Barbara Island Mitigation Area (Channel Islands Sanctuary Cautionary Area).

Response: The Channel Islands Sanctuary Cautionary Area was renamed the Santa Barbara Island Mitigation Area for the proposed rule. All locations within the HSTT Study Area have been used for Navy training and testing for decades. There has been no scientific evidence to indicate the Navy's activities are having adverse effects on populations of marine mammals, many of which continue to increase in number or are maintaining populations based on what regional conditions can support. This includes any marine mammal population that may transit through the Santa Barbara Island Mitigation Area. For example, the most recent NMFS U.S. West Coast survey findings (Moore and Barlow, 2017) encountered the highest estimated abundance of Mesoplodon beaked whales in the California Current since 1991. Multiple other surveys, monitoring efforts, and research projects continue to encounter long-term resident individuals such as populations of beaked whales in higher densities within the HSTT Study Area where various sonar systems have been in use for decades; see for example citation in the HSTT FEIS/OEIS to Debich et al. (2015a, 2015b), Falcone and Schorr (2012, 2014), Hildebrand et al. (2009), Moretti (2016), Širović et al. (2016), and Smultea and Jefferson (2014). The newest Navy-funded research, which was not available when the HSTT FEIS/OEIS was issued, continue to support the regular and repeated occurrence of marine mammal populations in HSTT including those thought most susceptible to behavioral response to anthropogenic sounds (DiMarzio et al., 2018; Lewis and Širović, in press; Moretti et al., 2017; Schorr et al., 2018; Širović et al., 2016, 2017, 2018; Širović et al., 2018). Navy research and monitoring funding continues within the HSTT Study Area under current NMFS MMPA and ESA permits, and is planned through the duration of any future permits. Given the lack of effects to marine mammal populations in the HSTT Study Area from surface ship sonars, the effects from intermittent, less frequent use of lower powered dipping mid-frequency active sonar or other mid-frequency active sonar and low-frequency sonars would also not significantly affect local populations.

Additionally, here has not been any Navy ship strike to marine mammals in SOCAL over the 8-year period from 2010-2018, and there has never been a Navy strike within the boundary of the Channel Islands National Marine Sanctuary over the course of strike record collection dating back 20 years. Therefore, ship strike risk to marine mammals transiting the Santa Barbara Island Mitigation Area is minimal. Additionally, as detailed in the analysis in the HSTT FEIS/OEIS Section 3.7.3.4.1 (Impacts from Vessels and In-Water Devices) and in Appendix K (Geographic Mitigation Assessment), there are important differences between most Navy vessels and their operation and commercial ships that individually make Navy vessels much less likely to strike a whale. Navy vessels already operate at a safe speed given a particular transit or activity need. This also includes a provision to avoid large whales by 500 yd; so long as safety of navigation and safety of operations is maintained. Previously, the Navy commissioned a vessel density and speed report for HSTT (CNA, 2016). Based on an analysis of Navy ship traffic in HSTT between 2011 and 2015, the average speed of all Navy vessels within Southern California is typically already low, with median speeds between 5 and 12 kn (CNA, 2016). Slowest speeds occurred closer to the coast and islands. However, sometimes during training or testing activities, higher speeds are required.

Finally, given the lack of population impact to marine species throughout SOCAL from Navy activities, lack of significant and repeated use of the small portion of waters within the Santa Barbara Island Mitigation Area by marine mammals, anticipated low individual residency times within the Mitigation Area, application of mitigation and protective measures as outlined in the HSTT FEIS/OEIS, documented safe speeds Navy vessels already navigate by, detailed Start Printed Page 66894assessments of realistic training and testing requirements and potential impacts of further restrictions, the Navy has adequately defined the most practicable mitigation measures in the HSTT FEIS/OEIS and Appendix K (Geographic Mitigation Assessment).

Comment 45: A commenter recommended additional mitigation areas for important beaked whale habitat in the Southern California Bight. A commenter asserted that it is important to focus substantial management efforts on beaked whales within the Navy's SOCAL Range Complex, which sees the greatest annual amount of sonar and explosives activity of any Navy range in the Pacific.

Response: The basis for this comment includes incorrect or outdated information or information that does not reflect the environment present in the HSTT Study Area, such as, “. . .beaked whale populations in the California Current have shown significant, possibly drastic declines in abundance over the last twenty years.” The citation provided in the footnote to the comment and postulated “decline” was for beaked whales up until 2008 (which does not take into account information from the last 10 years) and was a postulated trend for the entire U.S. West Coast, not data which is specific to the HSTT Study Area. As noted in Section 3.7.3.1.1.7 (Long-Term Consequences) of the HSTT FEIS/OEIS, the postulated decline was in fact not present within the SOCAL portion of the HSTT Study Area, where abundances of beaked whales have remained higher than other locations off the U.S. West Coast. In addition, the authors of the 2013 citation (Moore and Barlow, 2013) have published trends based on survey data gathered since 2008 for beaked whales in the California Current, which now includes the highest abundance estimate in the history of these surveys (Barlow 2016; Carretta et al., 2017; Moore and Barlow, 2017). Also, when considering the portion of the beaked whale population within the SOCAL portion of the HSTT Study Area and as presented in the HSTT FEIS/OEIS, multiple studies have documented continued high abundance of beaked whales and the long-term residency of documented individual beaked whales, specifically where the Navy has been training and testing for decades (see for example Debich et al., 2015a, 2015b; Dimarzio et al., 2018; Falcone and Schorr, 2012, 2014; Hildebrand et al., 2009; Moretti, 2016; Schorr et al., 2018; Širović et al., 2016; Smultea and Jefferson, 2014). There is no evidence that there have been any population-level impacts to beaked whales resulting from Navy training and testing in the SOCAL portion of the HSTT Study Area. The Navy did provide analysis and consideration of additional geographic mitigation for beaked whales in the Southern California Bight in Appendix K (Geographic Mitigation Assessment), Section K.7.2 (Southern California Public Comment Mitigation Area Assessment) and specifically Section K.7.2.7 (Northern Catalina Basin and the San Clemente Basin) of the HSTT FEIS/OEIS regarding the stated concern over the possible presence of Perrin's beaked whale. See Chapter 5 (Mitigation), Section 5.4.1.2 (Mitigation Area Assessment) of the HSTT FEIS/OEIS for additional details regarding the assessments of areas considered for mitigation.

Comment 46: A commenter recommended additional mitigation areas in the San Nicholas Basin. A commenter notes that the settlement agreement established a “refuge” from sonar and explosives activities in a portion of the whales' secondary habitat, outside the Southern California Anti-submarine Warfare Range (SOAR), with more management effort being necessary in the long term a commenter recommended at a minimum that NMFS should prescribe the “refuge” during the next five-year operation period and should consider all possible habitat-based management efforts, including but not limited to the expansion of this area further south towards SOAR, to address impacts on the small population of Cuvier's beaked whales associated with San Clemente Island. A commenter also commented the energetic costs of displacement of beaked whales into sub-optimal foraging habitat outweigh the costs of repeated sonar exposure for whale survival, while creating conditions of a population sink, such as has been seen on the Navy's AUTEC range (Claridge 2013).

Response: Navy did provide analysis and consideration of additional geographic mitigation for beaked whales in the San Nicolas Basin in Appendix K (Geographic Mitigation Assessment), Section K.7.2 (Southern California Public Comment Mitigation Area Assessment) and specifically Section K.7.2.1 (San Nicolas Basin) of the HSTT FEIS/OEIS. See Chapter 5 (Mitigation), Section 5.4.1.2 (Mitigation Area Assessment) of the HSTT FEIS/OEIS for additional details regarding the assessments of areas considered for mitigation.

Within San Nicolas Basin, there is a documented, recurring number of Cuvier's beaked whales strongly indicating that the Navy's activities areis not having a population-level impact to this species. This is supported by repeated visual re-sighting rates of individuals, sightings of calves and, more importantly, reproductive females, and passive acoustic assessments of steady vocalization rates and abundance over at least the most recent seven-year interval. It is incorrect to consider as fact that there is a “population sink, such as has been seen on the Navy's AUTEC range. In the citation provided (Claridge 2013), that statement is merely a hypothesis, yet to be demonstrated.

The Navy has been funding Cuvier's beaked whale research specifically in San Nicolas Basin since 2006. This research is planned to continue for at least the next five years through the duration of the planned HSTT MMPA permit. Cumulative from 2006 to 2016, over 170 individual Cuvier's beaked whales have been catalogued within San Nicolas Basin. Schorr et al. (2018) state for the most recent field season from 2016 to 2017 that: Identification photos of suitable quality were collected from 69 of the estimated 81 individual Cuvier's beaked whales encountered in 2016-2017. These represented 48 unique individuals, with eight of these whales sighted on two different days, and another three on three different days during the study period. Nineteen (39 percent) of these whales had been sighted in previous years. Many more whales identified in 2016 had been sighted in a previous year (16/28 individuals, 57 percent), compared to 2017 (5/22 individuals, 23 percent), though both years had sightings of whales seen as early as 2007. There were three adult females photographed in 2016 that had been sighted with calves in previous years, one of which was associated with her second calf. Additionally, a fourth adult female, first identified in 2015 without a calf, was subsequently sighted with a calf. The latter whale was sighted for a third consecutive year in 2017, this time without a calf, along with two other adult females with calves who had not been previously sighted. These sightings of known reproductive females with and without calves over time (n = 45) are providing critically needed calving and weaning rate data for Population Consequences of Disturbance (PcoD) models currently being developed for this species on SOAR.

In 2018, an estimate of overall abundance of Cuvier's beaked whales at the Navy's instrumented range in San Nicolas Basin was obtained using new dive-counting acoustic methods and an archive of passive acoustic M3R data representing 35,416 hours of data (DiMarzio, 2018; Moretti, 2017). Over the seven-year interval from 2010-2017, Start Printed Page 66895there was no observed change and perhaps a slight increase in annual Cuvier's beaked whale abundance within San Nicolas Basin (DiMarzio 2018). There does appear to be a repeated dip in population numbers and associated echolocation clicks during the fall centered around August and September (DiMarzio, 2018; Moretti, 2017). A similar August and September dip was noted by researchers using stand-alone off-range bottom passive acoustic devices in Southern California (Rice et al., 2017; Širović et al., 2016). This dip in abundance documented over 10 years of monitoring may be tied to some as yet unknown population dynamic or oceanographic and prey availability dynamic. It is unknown scientifically if this represents a movement to different areas by parts of the population, or a change in behavioral states without movement (i.e., breeding verse foraging). Navy training and testing events are spatially and temporally spread out across the SOCAL portion of the HSTT Study Area. In some years events occur in the fall, yet in other years events do not. Yet, the same dip has consistently been observed lending further evidence this is likely a population biological function.

Comment 47: A commenter recommended additional mitigation areas in the Santa Catalina Basin. A commenter commented that there is likely a small, resident population of Cuvier's beaked whales resides in the Santa Catalina Basin and that this population is subject to regular acoustic disturbance due to the presence of the Shore Bombardment Area (SHOBA) and 3803XX. The population may also be exposed to training activities that occupy waters between Santa Catalina and San Clemente Islands. Similar to the San Nicholas population, the settlement agreement established a “refuge” from sonar and explosives activities in the northern portion of the Santa Catalina Basin. A commenter recommended that, at a minimum the Navy should carefully consider implementing the “refuge” during the next five-year authorization period and should continue to consider all possible habitat-based management efforts to address impacts on the population.

Response: The water space areas mentioned in the comment as “(SHOBA)” off the southern end of San Clemente Island are waters designated as Federal Danger and Safety Zones via formal rule making (Danger Zone—33 CFR 334.950 and Safety Zone—33 CFR 165.1141) because they are adjacent to the shore bombardment impact area that is on land at the southern end of San Clemente Island. Waters designated as “3803XX,” which are associated with the Wilson Cove anchorages and moorings, where ship calibration tests, sonobuoy lot testing, and special projects take place, are designated as Federal Safety and Restricted Zones via formal rule making (Safety Zone—33 CFR 165.1141 and Restricted Zone—33 CFR 334.920).

The comment states a concern that a population of Cuvier's beaked whale is, “subject to regular acoustic disturbance due to the presence of the Shore Bombardment Area,” is not correct. The SHOBA is a naval gun impact area located on land at the southern end of San Clemente Island. This area is an instrumented land training range used for a variety of bombardment training and testing activities. The in-water administrative boundary for SHOBA does not delineate the locations where a ship firing at land targets must be located and does not represent where gunfire rounds are targeted. The water area in Santa Catalina Basin is a controlled safety zone in the very unlikely event a round goes over the island and lands in the water. With the modern advent of better precision munitions, computers, and advanced fire control, that probability is very remote. Navy vessels use the waters south of San Clemente Island (SHOBA West and SHOBA East) from which to fire into land targets on southern San Clemente Island (see the HSTT FEIS/OEIS Figure 2.1-7). Therefore, there would not be any underwater acoustic disturbance to Cuvier's beaked whales located within the Santa Catalina Basin from in-water explosives or ship firing.

Comment 48: A commenter recommended additional mitigation areas for the southernmost edge of the California Current, west of Tanner and Cortes Banks. In light of the importance of the Southernmost edge of the California Current, west of Tanner and Cortes banks, Commenters recommend assessing the designation of the southern offshore waters of the Southern California Bight as a seasonal time-area management area for Cuvier's beaked whales between November and June. The approximate coordinates are 32.75 N, 119.46 W (referenced as Site E). As part of this assessment, a commenter recommended that the boundaries be refined via expert consideration of acoustic and other relevant information pertaining to beaked whale biology and bathymetric and oceanographic data.

Response: Baumann-Pickering et al. (2014a, b, 2015), as the commenter referenced, did not specify this area as biologically important and the author's data only indicated there have been detections of the Cuvier's beaked whales within this area. Further, the species is widely distributed within Southern California and across the Pacific with almost all suitable deep water habitat greater than 800 m in Southern California conceivably containing Cuvier's beaked whales. Only limited population vital rates exist for beaked whales, covering numbers of animals, populations vs. subpopulations determination, and residency time for individual animals (Schorr et al., 2017, 2018). The science of passive acoustic monitoring is positioned to answer some questions on occurrence and seasonality of beaked whales, but cannot as of yet address all fundamental population parameters including individual residency time.

Furthermore, while passive acoustic monitoring within Southern California has been ongoing for 28 years, with many sites funded by the Navy, not all sites have been consecutively monitored for each year. All of the single bottom-mounted passive acoustic devices used for the analysis by Baumann-Pickering et al. (2014a, b, 2015), and used in the comment to support its argument, are not continuous and have various periodicities from which data have been collected. Specifically, devices have been deployed and removed from various locations with some sites having multiple years of data, others significantly less, with perhaps just a few months out of a year. For instance, Site E, located west of Tanner and Cortes Banks and used by the commenter to justify restrictions in this area, was only monitored for 322 days from September 2006 through July 2009 (obtaining slightly less than a full year's worth of data).

Site E was also used again for another 63 days from Dec 2010 through February 2011. During this second monitoring period at Site E, Gassman et al. (2015) reported detection of only three Cuvier's beaked whales over six separate encounters with time intervals of 10-33 minutes. As sources of data associated with a single monitoring point, the two monitoring episodes conducted at Site E may not be indicative of Cuvier's beaked whale presence at other locations within Southern California, which lack comparable monitoring devices. Nor would they be indicative of overall importance or lack of importance of the area west of Tanner and Cortes Banks. Further, more recent acoustic sampling of bathymetrically featureless areas off Southern California with drifting hydrophones conducted by NMFS, detected many beaked whales over abyssal plains and not associated with Start Printed Page 66896slope or seamount features. This counters a common misperception that beaked whales are primarily found over slope waters, in deep basins, or over seamounts (Griffins and Barlow 2016).

Most importantly, older passive acoustic data prior to 2009 may not be indicative of current or future occurrence of beaked whales, especially in terms of potential impact of climate change on species distributions within Southern California. To summarize, these limited periods of monitoring (322 days in a three-year period prior to 2010 and 63 days in 2011) may or may not be reflective of current beaked whale distributions within Southern California and into the future. Furthermore, passive acoustic-only detection of beaked whales, without additional population parameters, can only determine relative occurrence, which could be highly variable over sub-regions and through time.

While Cuvier's beaked whales have been detected west of Tanner and Cortes Banks, as noted above this species is also detected in most all Southern California locations greater than 800 m in depth. Furthermore, the Navy has been training and testing in and around Tanner and Cortes Banks with the same basic systems for over 40 years, with no evidence of any adverse impacts having occurred. Further, there are no indications that Navy training and testing in the Southern California portion of the HSTT Study Area has had any adverse impacts on populations of beaked whales in Southern California. In particular, a re-occurring population of Cuvier's beaked whales co-exists within San Nicolas Basin to the east, an area with significantly more in-water sonar use than west of Tanner and Cortes Banks.

To gain further knowledge on the presence of beaked whales in Southern California, the Navy continues to fund additional passive acoustic field monitoring, as well as research advancements for density derivation from passive acoustic data. For the five-year period from 2013 to 2017, U.S. Pacific Fleet on behalf of the U.S. Navy funded $14.2 million in marine species monitoring within Hawaii and Southern California. Specifically, in terms of beaked whales, the Navy has been funding beaked whale population dynamics, tagging, and passive acoustic studies within the HSTT Study Area since 2007 (DiMarzio et al., 2018; Moretti, 2017; Rice et al., 2017, Schorr et al., 2017, 2018; Širović, et al., 2017). Variations of these efforts are planned to continue through the duration of the next HSTT MMPA permit cycle using a variety of passive acoustic, visual, tagging, photo ID, and genetics research tools. This Navy effort is in addition and complementary to any planned NMFS efforts for beaked whales and other marine mammals. For instance, the Navy is co-funding with NMFS and the Bureau of Ocean Energy Management a planned Summer-Fall 2018 visual and passive acoustic survey along the U.S. West Coast and off Baja Mexico. New passive detection technologies focusing on beaked whales will be deployed during these surveys (similar to Griffiths and Barlow, 2016). The Navy continues SOCAL beaked whale occurrence and impact studies with additional effort anticipated through 2020.

Analysis of the southernmost edge of the California Current, west of Tanner-Cortes Bank and the presence of Cuvier's beaked whales was addressed in Appendix K (Geographic Mitigation Assessment), Section K.7.2.4 (Southernmost Edge of California Current, West of Tanner-Cortes Bank) and Section K.7.2.6 (Cuvier's Beaked Whale Habitat Areas Mitigation Assessment) of the HSTT FEIS/OEIS. Also see Chapter 3, Section 3.7.2.3.24 (Cuvier's Beaked Whale (Ziphius cavirostris)) of the HSTT FEIS/OEIS for additional information regarding this species.

As noted in Appendix K (Geographic Mitigation Assessment), the waters west of Tanner and Cortes Banks are also critical to the Navy's training and testing activities; therefore, it is not practicable to preclude activities within that water space in the SOCAL portion of the HSTT Study Area. Reasonable mitigation measures, as discussed in Appendix K (Geographic Mitigation Assessment), would limit the impact of training and testing on marine mammals, and especially beaked whales, in this area.

Given that there is no evidence that Navy training and testing activities are having significant impacts to population of beaked whales anywhere in the SOCAL portion of the HSTT Study Area, the uncertainty of current use by Cuvier's beaked whales of the area west of Tanner and Cortes Banks, the fact that general occurrence of beaked whales in Southern California may not necessarily equate to factors typically associated with biologically important areas, and consideration of the importance of Navy training and testing activities in the areas around Tanner and Cortes Banks discussed in Appendix K (Geographic Mitigation Assessment) of the HSTT FEIS/OEIS, additional geographic mitigation specifically for the area west of Tanner and Cortes Banks is not warranted.

As noted in Appendix K (Geographic Mitigation Assessment) and Chapter 5 (Mitigation), Section 5.3 (Procedural Mitigation to be Implemented) of the HSTT FEIS/OEIS, the Navy will continue to implement procedural mitigation measures throughout the HSTT Study Area.

Comment 49: A commenter commented that the same long-term passive acoustic study of the Southern California Bight as discussed for Cuvier's beaked whales above in Comment 48 also suggests that southern-central waters represent biologically important habitat for Perrin's beaked whale. A commenter recommended that the Northern Catalina Basin and the waters southeast of Santa Catalina Island (approximate coordinates of 33.28 N, −118.25 W), and the San Clemente Basin (approximate coordinates of 32.52 N, −118.32 W), both based on location of HARP deployments (referenced as sites “A” and “S”), be considered as management areas for Perrin's beaked whales. A commenter recommended that the boundaries of any restrictions be established via expert consideration.

Response: All of the single bottom-mounted passive acoustic devices used for the analysis by Baumann-Pickering et al. (2014) and used by the commenter to support their argument are not continuous and have various periodicities for which data have been collected. As single point sources of data, these passive acoustic devices may not be indicative of Perrin's beaked whale presence at other locations within Southern California without comparable devices. Nor would older data prior to 2009 be indicative of current or future occurrence especially in terms of potential impact of climate change on species distributions.

Navy-funded passive acoustic monitoring within the SOCAL portion of the HSTT Study Area has been ongoing for the past 21 years, but not all areas are monitored continuously, and devices have been deployed and removed from various locations. Santa Catalina Basin was only monitored from August 2005 to July 2009. Santa Catalina Basin has not been monitored under Navy funding since 2009 because other areas in Southern California were prioritized for passive acoustic device placement by the researchers. For San Clemente Island, the single monitoring site “S” used in Baumann-Pickering et al. (2014) and cited as the source of the comment's claim for San Clemente Basin was only deployed for a limited time of approximately 1.5 years, resulting in 409 days of data (September 2009-May 2011). For both sites Start Printed Page 66897combined, only 41 hours of BW43 signal types were detected over a cumulative approximately five-and-a-half years of monitoring. The 41 hours of BW43 detections therefore only represents a small fraction of overall recording time (less than 1 percent).

The beaked whale signal type detected called BW43 has been suggested as coming from Perrin's beaked whales (Baumann-Pickering et al. 2014), but not yet conclusively and scientifically confirmed.

A different Navy-funded single site south of San Clemente Island within the San Clemente Basin has had a passive acoustic device in place from July 2014 through current. Širović et al. (2016) and Rice et al. (2017) contain the most current results from San Clemente Basin site “N.” While Širović et al. (2016) and Rice et al. (2017) do report periodic passive acoustic detections of Mesoplodon beaked whales thought to be Perrin's beaked whale in San Clemente Basin, the overall detection rate, periodicity, and occurrence has not been high. Between May 2015 and June 2016, there were only seven weeks in which potential Perrin's beaked whale echolocation clicks were detected, with each week having less than 0.14 hours/week of detections. Acoustic sampling of bathymetrically featureless areas off Southern California with drifting hydrophones by NMFS detected many beaked whales over abyssal plains and not always associated with slope or seamount features, which counters a common misperception that beaked whales are primarily found over slope waters, in deep basins, or over seamounts (Griffins and Barlow 2016). One of these devices was deployed within the SOCAL portion of the HSTT Study Area. In addition, analysis of NMFS visual survey data from 2014, the most recent year available, showed an increase in Mesoplodon beaked whales along the entire U.S. West Coast, which the authors attributed to an influx of tropical species of Mesoplodon during the unusually warm water condition that year (Barlow 2016; Moore & Barlow 2017). Perrin's beaked whale, part of the Mesoplodon guild, could be part of these sightings. In summary, San Clemente Basin and Santa Catalina Basin with similar low passive acoustic detection rates are likely to be part of Perrin beaked whale's general distribution along the U.S. West Coast and in particular Southern California and Baja Mexico. This distribution is likely to be wide ranging for Perrin's beaked whales as a species and highly correlated to annual oceanographic conditions. Santa Catalina and San Clemente basins do have infrequent suspected Perrin's beaked whale passive acoustic detections from a limited number of devices, but these areas may not specifically represent unique high occurrence locations warranting geographic protection beyond existing Navy protective measures.

The Navy has been training and testing in and around the Northern Catalina Basin and waters southeast of Santa Catalina Island with the same systems for over 40 years, and there is no evidence of any adverse impacts having occurred and no indications that Navy training and testing has had any adverse impacts on populations of beaked whales in Southern California. The main source of anthropogenic noise in the Catalina Basin and waters south of San Clemente Island are associated with commercial vessel traffic concentrated in the northbound and southbound lanes of the San Pedro Channel that runs next to Santa Catalina Island and leads to and from the ports of Los Angeles/Long Beach and other commercial traffic from San Diego and ports to the north and south of Southern California. These waters in and around Northern Catalina Basin and waters southeast of Santa Catalina Island are critical to the Navy's training and testing activities, and so it is not practicable to limit or reduce access or preclude activities within that water space in the SOCAL portion of the HSTT Study Area.

The Santa Catalina Basin area and Perrin's beaked whales were addressed in Appendix K (Geographic Mitigation Assessment), Section K.7.2.3 (Catalina Basin) and K.7.2.7 (Northern Catalina Basin and the San Clemente Basin) of the HSTT FEIS/OEIS. Also see Appendix K (Geographic Mitigation Assessment), Section K.7.2.7.2 (Northern Catalina Basin and Waters Southeast of Catalina Island Perrin's Beaked Whale Habitat Mitigation Considerations) of the HSTT FEIS/OEIS for additional information regarding this species. Additional limitations as discussed in Appendix K (Geographic Mitigation Assessment) would limit training and impact readiness. Given that there is no evidence of impacts to the population of beaked whales in the area, and low potential occurrence of Perrin's beaked whales in the Southern California portion of the HSTT Study Area, geographic mitigation would not effectively balance a reduction of biological impacts with an acceptable level of impact on military readiness activities. As noted in Appendix K (Geographic Mitigation Assessment) and Chapter 5, Section 5.3 (Procedural Mitigation to be Implemented) of the HSTT FEIS/OEIS, the Navy will continue to implement procedural mitigation measures throughout the HSTT Study Area.

Comment 50: Commenters recommended additional mitigation areas for important fin whale habitat off Southern California. The commenters recommended that the waters between the 200 m and 1000 m isobaths be assessed for time-area management so that, at minimum, ship strike awareness measures for fin whales can be implemented during the months of November through February, when the whales aggregate in the area.

Response: As described and detailed in the HSTT FEIS/OEIS, the Navy implements a number of ship-strike risk reduction measures for all vessels, in all locations and seasons, and for all marine mammal species. New research by Širović et al. (2017) supports a hypothesis that between the Gulf of California and Southern California, there could be up to four distinct sub-populations based on fin whale call types, including a Southern California resident population. There is also evidence that there can be both sub-population shifts and overlap within Southern California (Širović et al., 2017). Scales et al. (2017) also postulated two Southern California sub-populations of fin whales based on satellite tagging and habitat modeling. Scales et al. (2017) stated that some fin whales may not follow the typical baleen whale migration paradigm, with some individuals found in both warm, shallow nearshore waters <500 m, and deeper cool waters over complex seafloor topographies. Collectively, the author's spatial habitat models with highest predicted occurrence for fin whales cover the entire core training and testing portion of the SOCAL portion of the HSTT Study Area, not just areas between 200 and 1,000 m. Results from Navy-funded long-term satellite tagging of fin whales in Southern and Central California still shows some individual fin whales engage in wide-ranging movements along the U.S. West Coast, as well as large daily movements well within subareas (Mate et al., 2017). In support of further refining the science on Southern California fin whales, Falcone and Schorr (2014) examined fin whale movements through photo ID and short-to-medium term (days-to-several weeks) satellite tag tracking under funding from the Navy. The authors conducted small boat surveys from June 2010 through January 2014, approximately three-and-a-half years. Of interest in terms of the comment and the 200-1,000 m isobaths occurrence, more fin whale tag locations were reported off the Palos Verdes Start Printed Page 66898Peninsula and off of the Los Angeles/Long Beach commercial shipping ports in fall, both areas north of and outside of the Navy's Southern California Range Complex. Compared to the above areas, there were not as many tag locations in the similar isobaths region off San Diego associated with the Navy range area. Falcone and Schorr (2014) did document an apparent inshore-offshore distribution between Winter-Spring and Summer-Fall. Given the apparent resident nature of some fin whales in Southern California as discussed in Falcone and Schorr (2014), Scales et al. (2017), and Širović et al. (2017), it remains uncertain if the inshore-offshore seasonal pattern as well as sub-population occurrence will persist into the future, or if fin whales will change distribution based on oceanographic impacts on available prey (ex. El Nino, climate change, etc.). The efforts from Falcone and Schorr on fin whales began in 2010 and are planned to continue for the next several years under Navy monitoring funding to further refine fin whale population structure and occurrence within Southern California.

The data from the various single bottom-mounted passive acoustic devices used in the analysis are not continuous and have various periodicities for which data have been collected. Many of these devices are purposely placed in 200-1000 m of water. Given these are point sources of data, they may or may not be indicative of fin whale calling or presence at other locations within Southern California without devices. Passive acoustic analysis is only useful for those individuals that are calling and may not indicate total population occurrence. Low-frequency fin whale calls by their very nature have relatively long underwater propagation ranges so detections at a single device could account for individuals 10-50 miles away if not further, depending on local propagation conditions. This would mean calling whales are not in the 200-1000 m area. Širović et al. (2015) acknowledge in discussing their data biases, that their use of “call index” may best indicate a period of peak calling. But fin whales produce multiple call types depending on behavioral state. Based on technology limitations, some fin whale call types were not included in Širović et al. (2015).

1. The study cited by a commenter (Širović et al., 2015) and used as the basis for “Figure 3” concerns trends seen within the Southern California Bight, not exclusively the SOCAL Range Complex;

2. The research used as the basis for Figure 3 was funded by the Navy to develop baseline information for the areas where Navy trains and tests and was by no means designed to or otherwise intended as a representative sample of all waters off California or the entire habitat of the fin whale population in the area;

3. It is not correct to assume detected vocalizations (a “call index”) reported in Širović et al. (2015) for fin whales equates with where fin whales are aggregated in the Southern California Bight. For example, the acoustic monitoring data did not pick up or otherwise correspond to the observed seasonal distribution shift of fin whales indicated by visual survey data covering the same time periods (Campbell et al., 2015; Douglas et al., 2014);

4. Širović et al. (2015) make no such claim of aggregations during the winter months but instead compare call index rates and state that the purpose for the paper was to demonstrate that passive acoustics can be a powerful tool to monitor population trends, not relative abundances;

5. There is no science to support the contention that fin whales are “at particular risk of ship-strike on the naval range.” Two fin whales were struck by the Navy in 2009 in the Southern California portion of the HSTT Study Area as Navy noted in Appendix K (Geographic Mitigation Assessment), but there have been no fin whales struck and in fact no whales of any species struck in the subsequent nine-year period despite a documented increase in the fin whale population inhabiting the area (Barlow, 2016; Moore & Barlow, 2011; Smultea & Jefferson, 2014). Furthermore, one of those vessel strikes occurred at the end of the recommended mitigation timeframe (February) and the other well outside the time period (May), so the proposed mitigation would only have been marginally effective, if at all. Neither of these Navy fin whale strike locations were close to shore (both >50-60 Nmi from shore), or associated with coastal shipping lanes. Based on an analysis of Navy ship traffic in the HSTT Study Area between 2011 and 2015, median speed of all Navy vessels within Southern California is typically already low, with median speeds between 5 and 12 knots (CNA, 2016). This includes areas within and outside of 200-1000 m within Southern California, with slowest speeds closer to the coast; and

6. As presented in the EIS/OEIS, fin whales are present off all the waters of Southern California year-round (Širović et al., 2015, 2017). Using available quantitative density and distribution mapping, the best available science, and expert elicitation, definitive areas of importance for fin whales could not be determined by a panel of scientists specifically attempting to do so (Calambokidis et al., 2015).

Navy vessels already operate at a safe speed given a particular transit or activity need. This also includes a provision to avoid large whales by 500 yards, so long as safety of navigation and safety of operations is maintained. Previously, the Navy commissioned a vessel density and speed report for HSTT (CNA, 2016). Based on an analysis of Navy ship traffic in HSTT between 2011 and 2015, median speed of all Navy vessels within Southern California is typically already low, with median speeds between 5 and 12 knots (CNA, 2016). Slowest speeds occurred closer to the coast and islands.

In conclusion, speed restrictions within 200-1000 m is unwarranted given the wide range of fin whale movements along the U.S. West Coast including areas within and outside of 200-1000 m contours, sometimes large-scale daily movements within regional areas as documented from Navy-funded satellite tagging, the current lack of ship strike risk from Navy vessels in Southern California (2010-2017), the already safe training and testing ship speeds Navy uses within HSTT, and existing Navy mitigation measures including provisions to avoid large whales by 500 yards where safe to do so.

In addition, the Navy agreed to send out seasonal awareness messages of blue, fin, and gray whale occurrence to improve awareness of all vessels operating to the presence of these species in SOCAL.

Hawaii Areas

Comment 51: NPS recommends that the Navy consider the following as it plans to conduct activities in the HSTT Study Area. NPS notes units of the NPS system that occur near training and testing areas around Hawaii and identify which can be affected by noise. The Units are: Kaloko-Honokohau National Historical Park (NHP), Pu'uhonua o Honaunau NHP, Pu'ukolhola Heiau National Historic Site, Kalaupapa NHP, and the World War II Valor in the Pacific National Monument.

Response: National Parks and Marine protected areas in are addressed in Chapter 6 of the HSTT FEIS/OEIS. Kalaupapa National Historical Park (NHP) is discussed in Comment 52 below. No planned activities overlap with Kaloko-Honokohau NHP; therefore, no impacts are expected within the Kalaupapa NHP. The Pu'uhonua o Honaunau NHP and Pu'ukolhola Heiau National Historic Site are not specifically addressed in Chapter 6 of Start Printed Page 66899the FEIS/OEIS, but neither site appears to contain any marine waters. The Navy's planned activities do not occur on land except in designated training areas on Navy properties (i.e., for amphibious assaults, etc.); therefore, there are no activities that overlap with these sites and no impacts are expected. The WWII Valor in the Pacific Monument is for the USS Arizona which is a Navy war memorial. No activities occur within the boundary of the site itself, and the monument was not designated to protect marine species. There are training and testing activities that occur within Pearl Harbor as a whole, and impacts to marine mammals in the waters of Pearl Harbor as a whole were include in Navy's proposed activities and therefore analyzed by NMFS in this final rule.

Comment 52: The NPS noted the presence of marine mammal species in the Kalaupapa NHP (on the north shore of Molokai), and is concerned about potential take of protected species that inhabit water out to 1000 fathoms, and recommended the Navy consider alternate training areas to avoid impacts to these species. Species that occur year-round include the false killer whale, sperm whale, pygmy sperm whale, spinner dolphin, and bottlenose dolphin. Humpback whales are seasonal visitors from November to April. The Hawaiian monk seal pups are within the Kalaupapa NHP during the Spring and Summer.

Response: Part of the Kalaupapa NHP (northern portion) is protected by the measures employed inside the 4-Islands Region Mitigation Area such as year-round prohibition on explosives and no use of MF1 surface ship hull mounted mid-frequency active sonar from November 15-April 15).

We note, however, that the majority of the Kalaupapa NHP is not in the 4-Islands Region Mitigation Area as it is mainly landbased, but just outside it. The Kalaupapa NHP was designated to protect the two historic leper colonies on the property and was not designated with the purpose of protecting marine species. The boundaries of the Kalaupapa NHP extend a quarter mile offshore. The Navy does propose conducting activities associated with the planned activities in the boundary of the the Kalaupapa NHP. There would be no effect to Hawaiian monk seal pupping on NHP land as the Navy does not have any planned activities in the boundary of the Kalaupapa NHP, especially on land. The Navy's planned activities do not include any land-based activities except for a few activities which are conducted on designated Navy property (i.e., amphibious assaults on Silver Strand, etc.). Further, as the seaspace adjacent to the Kalaupapa NHP is not an established training or testing area, it is unlikely naval activity would occur in this area.

Comment 53: A commenter recommended expanding the Hawaii Island Mitigation Area westward to protect resident Cuvier's beaked whales and rough-toothed dolphins. The boundaries of the Hawaii Island Mitigation Area should be expanded westward to remain consistent with the boundaries of the BIAs defined in Baird et al. (2015), which informed the boundaries of Conservation Council Settlement Areas 1-C and 1-D. This expansion will cover habitat for Cuvier's beaked whales and toothed dolphins that are resident around the Big Island.

Response: Analyses of the marine mammal species mentioned in the comment and considered within the Hawaii Island Mitigation Area are discussed throughout Appendix K (Geographic Mitigation Assessment), Section K.3 (Biologically Important Areas within the Hawaii Range Complex Portion of the HSTT Study Area) and Sections K.5.1 (Settlement Areas Within the Hawaii Portion of the HSTT Study Area) through K.5.4 (Proposed Mitigation Areas that Overlap the Hawaii Portion of the HSTT Settlement Agreement Areas) of the HSTT FEIS/OEIS. Additional information on the marine mammals mentioned in the comment is also provided in the species-specific sub-sections in Chapter 3, Section 3.7.2 (Affected Environment) of the HSTT FEIS/OEIS. Based on these analyses, the Navy will implement additional mitigation within the Hawaii Island Mitigation Area (year-round) as detailed in Chapter 5, Section 5.4.2 (Mitigation Areas for Marine Mammals in the Hawaii Range Complex) of the HSTT FEIS/OEIS, to further avoid or reduce impacts on marine mammals from acoustic and explosive stressors from the planned activities.

The mitigation requirement of prohibiting the use of explosives year-round during training and testing across the entire Hawaii Island Mitigation Area satisfies the previous mitigation requirement of a prohibition on the use of in-water explosives for training and testing activities of the Settlement Agreement for Areas 1-A, 1-C, and 1-D, and further extends that requirement to the `Alenuihāhā Channel (Area 1-B). The Hawaii Island Mitigation Area still includes 100 percent of Settlement Areas 1-C and 1-D and includes a large majority of the BIAs for Cuvier's Beaked Whale (Hawaii Island BIA) and Rough-Toothed Dolphins (Hawaii Island BIA) (the areas in question by this comment). Particularly, it covers 93.30 percent of the Cuvier's Beaked Whale BIA westward of Hawaii Island and 83.58 percent of Rough-toothed dolphins Hawaii Island BIA westward of Hawaii Island.

Only the northern portion of the Cuvier's beaked whale BIA in Alenuihaha Channel and a smaller offshore portion of the BIA west of Hawaii are not covered by mitigations included in the Hawaii Island Mitigation Area on the west and east of Hawaii Island. The BIAi s based on the known range of the island-associated population, and the authors suggest that “the range of individuals from this population is likely to increase as additional satellite-tag data become available” (Baird et al., 2015b). Cuvier's beaked whales are not expected to be displaced from their habitat due to training and testing activities further offshore in these small areas of the biologically important area, given that the biologically important area covers 23,583 km2, is unbroken and continuous surrounding the island, and the BIA likely underrepresents their range. The small portion of the BIA that does not overlap the Hawaii Island Mitigation Area is offshore, and according to the most recent stock assessment approximately 95 percent of all sighting locations were within 45 km of shore. Additionally, consequences to individuals or populations are not unknown. No PTS is estimated or authorized. A small numbers of TTS and Level B behavioral harassment takes for Cuvier's beaked whales are estimated across the entire Hawaii portion of the Study Area due to acoustic stressors. Most of the TTS and Level B behavioral harassment takes for Cuvier's beaked whales are associated with testing in the Hawaii Temporary Operating Area, impacting the pelagic population (see Figure 3.7-36 of the HSTT FEIS/OEIS). It is extremely unlikely that any modeled takes would be of individuals in this small portion of the BIA that extends outside the Hawaii Island Mitigation Area.

Long-term and relatively comprehensive research has found no evidence of any apparent effects while documenting the continued existence of multiple small and resident populations of various species as well as long-term residency by individual beaked whales spanning the length of the current studies that exceed a decade. Further, the Navy has considered research showing that in specific contexts (such as associated with urban noise, commercial vessel traffic, eco-tourism, or whale watching, Chapter 3, Section 3.7.2.1.5.2 (Commercial Industries)) of Start Printed Page 66900the HSTT FEIS/OEIS that chronic repeated displacement and foraging disruption of populations with residency or high site fidelity can result in population-level effects. As also detailed in the HSTT FEIS/OEIS, however, the Navy training and testing activities do not equate with the types of disturbance in this body of research, nor do they rise to the level of chronic disturbance where such effects have been demonstrated because Navy activities are typically sporadic and dispersed. There is no evidence to suggest there have been any population-level effects in the waters around Oahu, Kauai, and Niihau or anywhere in the HSTT Study Area. In the waters around Oahu, Kauai, and Niihau, documented long-term residency by individuals and the existence of multiple small and resident populations are precisely where Navy training and testing have been occurring for decades, strongly suggesting a lack of significant impact to those individuals and populations from the continuation of Navy training and testing.

Mark-recapture estimates derived from photographs of rough-toothed dolphins taken between 2003 and 2006 resulted in a small and resident population estimate of 198 around the island of Hawaii (Baird et al., 2008), but those surveys were conducted primarily with 40 km of shore and may underestimate the population. Data do suggest high site fidelity and low population size for the island-associated population. There are no tagging data to provide information about the range of the island-associated population; the biologically important area is based on sighting locations and encompasses 7,175 km2. Generally, this species is typically found close to shore around oceanic islands. Only approximately half of the BIA offshore is not covered by the Hawaii Island Mitigation Area, where the BIA overlaps with special use airspace. Consequences to individuals or populations are not unknown. No PTS is estimated or authorized. Some TTS and Level B behavioral harassment takes due to acoustic stressors for this species across the entire HSTT Study Area (see Figure 3.7-66). Significant impacts on rough-toothed dolphin natural behaviors or abandonment due to training with sonar and other transducers are unlikely to occur within the small and resident population area. A few minor to moderate TTS or Level B behavioral harassment to an individual over the course of a year are unlikely to have any significant costs or long-term consequences for that individual, and nothing in the planned activities is expected to cause a “catastrophic event.” The Navy operating areas west of Hawaii Island are used commonly for larger events for a variety of reasons described further in Section K.3 (Biologically Important Areas Within the Hawaiian Range Complex Portion of the HSTT Study Area) (e.g., the relatively large group of seamounts in the open ocean offers challenging bathymetry in the open ocean far away from civilian vessel traffic and air lanes where ships, submarines, and aircraft are completely free to maneuver) and sonar may be used by a variety of platforms. Enlarging the Hawaii Island Mitigation Area is not anticipated to realistically reduce adverse impacts. Expanding the Hawaii Island Mitigation Area has a limited likelihood of further reducing impacts on marine mammal species or stocks and their habitat, while these open ocean operating areas for important for training and testing and, in consideration of these factors (and the broader least practicable adverse impact considerations discussed in the introduction), NMFS has determined that requiring this additional mitigation is not appropriate.

Comment 54: A commenter recommended limiting MTEs to reduce cumulative exposure in the Hawaii Island Mitigation Area.

Response: Prohibiting MTEs outright or spatially separating them within the Hawaii Island Mitigation Area (which includes the formerly named Planning Awareness Area) was proposed as additional mitigation to ensure that “marine mammal populations with highly discrete site fidelity . . . are not exposed to MTEs within a single year.” The goal of geographic mitigation is not to be an absolute, outright barrier and stop exposing animals to exercises per se; it is to reduce adverse impacts to the maximum extent practicable. Impacts associated with major training exercises, including cumulative impacts, are addressed in Chapters 3 (Affected Environment and Environmental Consequences) and Chapter 4 (Cumulative Impacts) of the HSTT FEIS/OEIS, and Navy quantitative analysis using the best available science has determined that training and testing activities will not have population-level impacts on any species. As determined in Chapter 3, Section 3.7.4 (Summary of Potential Impacts on Marine Mammals) of the HSTT FEIS/OEIS, it is not anticipated that the Proposed Action will result in significant impacts to marine mammals. To date, the findings from research and monitoring and the regulatory conclusions from previous analyses by NMFS are that the majority of impacts from Navy training and testing activities are not expected to have deleterious impacts on the fitness of any individuals or long-term consequences to populations of marine mammals.

MTEs cannot be moved around within the Hawaii Island Mitigation Area, given that those activities are specifically located to leverage particular features like the Alenuihaha Channel and the approaches to Kawaihae Harbor. This recommendation is not, therefore, appropriate in consideration of NMFS' least practicable adverse impact standard.

To limit activities, the Navy will not conduct more than 300 hours of MF1 surface ship hull-mounted mid-frequency active sonar or 20 hours of MF4 dipping sonar, or use explosives that could potentially result in takes of marine mammals during training and testing in the Hawaii Mitigation Area.

Comment 55: A commenter recommended prohibiting or restricting other sources of mid-frequency active sonar in the Hawaii Island Mitigation Area including prohibiting the use of helicopter-deployed mid-frequency active sonar in the Hawaii Island Mitigation Area.

Response: The Navy is already limiting other sources of MFAS. Between the application and the proposed rule, the Navy added new mitigation that includes a limit to the annual use of helicopter dipping sonar in the Hawaii Island Mitigation Area. Specifically, the Navy will not conduct more than 20 hours of MF4 dipping sonar that could potentially result in takes of marine mammals during training and testing. Helicopters deploy MFAS from a hover position in bouts generally lasting under 20 minutes, moving rapidly between sequential deployment and their duration of use and source level (217 dB) are generally well below those of hull-mounted frequency sonar (235 dB). All locations within the HSTT Study Area have been used for Navy training and testing for decades. There has been no scientific evidence to indicate the Navy's activities are having adverse effects on populations of marine mammals, many of which continue to increase in number or are maintaining populations based on what regional conditions can support. Navy research and monitoring funding continues within the HSTT Study Area under current NMFS MMPA and ESA permits, and is planned through the duration of any future permits. Given the lack of effects to marine mammal populations in the HSTT Study Area from larger, more powerful surface ship sonars, the effects from intermittent, less Start Printed Page 66901frequent use of lower powered mid-frequency dipping sonar or other mid-frequency active sonars would also not significantly affect small and resident populations.

Comment 56: A commenter recommended extending the 4-Islands Region Mitigation Area westward to encompass the Humpback Whale Special Reporting Area in Kaiwi Channel. Additionally the 4-Island Region Mitigation Area is inadequate to protect endangered Main Hawaiian Island insular false killer whales as the Main Hawaiian Island insular false killer whale is highly range-restricted to certain high-use areas, one of which includes the ESA critical habitat and the BIA north of Maui and Molokai (“False killer whale Hawaii Island to Niihau” BIA).

Response: The portion of the special reporting area that extends into Kaiwi Channel over Penguin Bank (equivalent to settlement area 2A) is generally not a higher use area for Main Hawaiian Island insular false killer whales and does not overlap significantly with the biologically important area. As presented in Chapter 3 (Affected Environment and Environmental Consequences), Navy quantitative analysis indicates that significant impacts on false killer whale natural behaviors or abandonment due to training with sonar and other transducers are unlikely to occur within the entire small and resident population area, let alone in the small sub-portion of the biologically important area that overlaps the proposed extension. Additionally, most of the modeled takes are for the Hawaii pelagic population of false killer whale (see Figure 3.7-46 and Table 3.7-31). Also, as described in more detail in Appendix K of the HSTT FEIS/OEIS, due to training and testing needs, the expansion of this area is considered impracticable.

Comment 57: A commenter recommended extending to year-round restrictions in the 4-Island Region Mitigation Area and the proposed extension into the Kaiwi Channel Humpback Whale Special Reporting Area.

Response: The additional expansion requested in the comment is not expected to reduce adverse impacts to an extent that would outweigh the negative impacts if unit commanders were unable to conduct unit-level training and testing, especially as they pass over Penguin Bank while transiting between Pearl Harbor and other parts of the Study Area. Prohibiting mid-frequency active sonar would preclude the Submarine Command Course from meeting its objectives and leveraging the important and unique characteristics of the 4-Islands Region, as described in multiple sections of Appendix K (e.g., Section K.3.1.6 (4-Islands Region and Penguin Bank Humpback Whale Reproduction Area, and Settlement Area 2-A and 2-B)). Penguin Bank is particularly used for shallow water submarine testing and anti-submarine warfare training because of its large expanse of shallow bathymetry. The conditions in Penguin Bank offer ideal bathymetric and oceanographic conditions allowing for realistic training and testing and serve as surrogate environments for active theater locations.

Additionally, this mitigation would further increase reporting requirements. As discussed in Chapter 5 (Mitigation) Section 5.5.2.6 (Increasing Reporting Requirements) of the HSTT FEIS/OEIS, the Navy developed its reporting requirements in conjunction with NMFS, balancing the usefulness of the information to be collected with the practicability of collecting it. An increase in reporting requirements as a mitigation would draw the event participants' attentions away from the complex tactical tasks they are primarily obligated to perform (such as driving a warship), which would adversely impact personnel safety, public health and safety, and the effectiveness of the military readiness activity. Expanding the Mitigation Area and extending the restrictions is not, therefore, appropriate in consideration of NMFS' least practicable adverse impact standard.

Comment 58: A commenter recommended implementing vessel speed restrictions within the 4-Islands Region Mitigation Area.

Response: This mitigation measure was proposed to address impacts on humpback whales due to both ship noise and ship strikes. As described and detailed in the Draft EIS, the Navy already implements a number of ship-strike risk reduction measures for all vessels, in all locations and seasons, and for all marine mammal species. The Navy cannot implement mitigation that restricts vessel speed during training or testing in the HSTT Study Area. Vessels must be able to maneuver freely as required by their tactics in order for training events to be effective. Imposition of vessel speed restrictions would interfere with the Navy's ability to complete tests that must occur in specific bathymetric and oceanic conditions and at specific speeds. Navy vessel operators must test and train with vessels in such a manner that ensures their ability to operate vessels as they would in military missions and combat operations (including being able to react to changing tactical situations and evaluate system capabilities). Furthermore, testing of new platforms requires testing at the full range of propulsion capabilities and is required to ensure the delivered platform meets requirements. Based on an analysis of Navy ship traffic in the HSTT Study Area between 2011 and 2015, median speed of all Navy vessels within Hawaii is typically already low, with median speeds between 8-16 kn (CNA, 2016). Speed restrictions in the Cautionary Area (renamed the 4-Islands Region Mitigation Area) are unwarranted given the movement of all social groups throughout the islands outside the Mitigation Area, the current lack of ship strike risk from Navy vessels in Hawaii (2010-2017), the already safe training and testing ship speeds the Navy uses within HSTT, and existing Navy mitigation measures, including provisions to avoid large whales by 500 yards where safe to do so. Implementing speed restrictions in the Mitigation Area is not, therefore, appropriate in consideration of NMFS' least practicable adverse impact standard.

Information on the response of baleen whales to vessel noise is presented in Section 3.7.3.1.1.5 (Behavioral Reactions) and Section 3.7.3.1.5 (Impacts from Vessel Noise). Impacts, if they did occur, would most likely be short-term masking and minor behavioral responses. Therefore, significant impacts on humpback whale reproductive behaviors from vessel noise associated with training activities are not expected. Navy vessels are intentionally designed to be quieter than civilian vessels, and ship speed reductions are not expected to reduce adverse impacts on humpback whales due to vessel noise.

Comment 59: A commenter recommended prohibiting the use of in-water explosives in the 4-Islands Region Mitigation Area.

Response: The Navy has agreed to implement a year-round restriction on the use of in-water explosives that could potentially result in takes of marine mammals during training and testing. Should national security present a requirement explosives that could potentially result in the take of marine mammals during training or testing, naval units will obtain permission from the appropriate designated Command authority prior to commencement of the activity. The Navy will provide NMFS with advance notification and include the information (e.g., sonar hours or explosives usage) in its annual activity reports submitted to NMFS.

Comment 60: A commenter recommended prohibiting other sources Start Printed Page 66902of MFAS in the 4-Islands Region Mitigation Area.

Response: NMFS reviewed Navy's assessment for the 4-Islands Mitigation Area. This area provides a unique and irreplaceable shallow water training capability for units to practice operations in littoral areas that are both shallow and navigationally constrained (HSTT FEIS Appendix K (Geographic Mitigation Assessment), Section K.3.3.1.6). The 4-Islands Region provides an environment for anti-submarine warfare search, tracking and avoidance of opposing anti-submarine warfare forces. The bathymetry provides unique attributes and unmatched opportunity to train in searching for submarines in shallow water. Littoral training allows units to continue to deploy improved sensors or tactics in littoral waters. In the Hawaii portion of the HSTT Study Area specifically, anti-submarine warfare training in shallow water is vitally important to the Navy since diesel submarines typically hide in that extremely noisy and complex marine environment (Arabian Gulf, Strait of Malacca, Sea of Japan, and the Yellow Sea all contain water less than 200 m deep). There is no other area in this portion of the HSTT Study Area with the bathymetry and sound propagation analog to seas where Navy conducts real operations that this training could relocate to. The Navy cannot conduct realistic shallow water training exercises without training in and around the 4-Islands Region Mitigation Area. In addition, this area includes unique shallow water training opportunities for unit-level training, including opportunity to practice operations in littoral areas that are both shallow, and navigationally constrained, and in close proximity to deeper open ocean environments. While MFAS is used infrequently in this area, a complete prohibition of all active sonars would impact Navy training readiness in an area identified as important for the Navy based on its unique bathymetry. However, the Navy recognizes the biological importance of this area to humpback whales during the reproductive season and with NMFS concurrence strives to limit the use of surface ship hull-mounted MFAS during that time of year. While the Navy has been training and testing in the area with the same basic systems for over 40 years, there is no evidence of any adverse impacts having occurred, and there are multiple lines of evidence demonstrating the small odontocete population high site fidelity to the area.

Comment 61: A commenter recommended prohibiting the use of helicopter-deployed mid-frequency active sonar in the 4-Islands Region Mitigation Area.

Response: The commenter's request to prohibit “air-deployed” mid-frequency active sonar is based on one paper (Falcone et al., 2017), which is a Navy-funded project designed to study the behavioral responses of a single species, Cuvier's beaked whales, to mid-frequency active sonar. The Navy relied upon the best science that was available to develop behavioral response functions for beaked whales and other marine mammals in consultation with NMFS for the Draft EIS/OEIS. The article cited in the comment (Falcone et al., 2017) was not available at the time the Draft EIS/OEIS was published but does not change the current FEIS/OEIS criteria or conclusions. The new information and data presented in the article was thoroughly reviewed when it became available and further considered in discussions with some of the paper's authors following its first presentation in October 2017 at a recent scientific conference. Many of the variables requiring further analysis for beaked whales and dipping sonar impact assessment are still being researched under continued Navy funding through 2019.

There are no beaked whale biologically important areas in the 4-Islands Region Mitigation Area, and the Mitigation Area is generally shallower than beaked whales' preferred habitat. Behavioral responses of beaked whales from dipping and other sonars cannot be universally applied to other marine mammal species. Research indicates that there are distinct individual variations as well as strong behavioral state considerations that influence any response or lack of response (Goldbogen et al., 2013; Harris et al., 2017). Therefore, it is expected that other species would have highly variable individual responses ranging from some response to no response to any anthropogenic sound. This variability is accounted for in the Navy's current behavioral response curves described in the HSTT Draft EIS/OEIS and supporting technical reports.

Furthermore, the potential effects of dipping sonar have been rigorously accounted for in the Navy's analysis. Parameters such as power level and propagation range for typical dipping sonar use are factored into HSTT acoustic impact analysis along with guild specific criteria and other modeling variables, as detailed in the HSTT DEIS/OEIS and associated technical reports for criteria and acoustic modeling. Further, due to lower power settings for dipping sonar, potential impact ranges of dipping sonar are significantly lower than surface ship sonars. For example, the HSTT average modeled range to TTS of dipping sonar for a 1-second ping on low-frequency cetacean (i.e., blue whale) is 77 m, and for mid-frequency cetaceans including beaked whales is 22 m (HSTT FEIS/OEIS Table 3.7-7). This range is easily monitored for marine mammals by a hovering helicopter and is accounted for in the Navy's proposed mitigation ranges for dipping sonars (200 yds. or 183 m). Limited ping time (i.e., less dipping sonar use as compared to typical surface ship sonar use) and lower power settings therefore would limit the impact from dipping sonar to any marine mammal species.

This is an area of extremely low use for air-deployed mid-frequency active sonar. Prohibiting air-deployed mid-frequency active sonar in the Mitigation Area would not be any more protective to marine mammal populations generally, or the Main Hawaiian Islands insular false killer whale in particular, than currently implemented procedural mitigation measures for air-deployed mid-frequency active sonar and is not, therefore, appropriate in consideration of NMFS' least practicable adverse impact standard.

Comment 62: A commenter recommended prohibiting use of low-frequency active sonar in the 4-Islands Region Mitigation Area.

Response: The commenters suggested that “Baleen whales are vulnerable to the impacts of low-frequency active sonar, particularly in calving areas where low-amplitude communication calls between mothers and calves can be easily masked.” As described in Chapter 3, Section 3.7.2.3.1 (Humpback Whale (Megaptera novaeangliae), Hawaii DPS) of the HSTT FEIS/OEIS, the best available science has demonstrated humpback whale population increases and an estimated abundance greater than some pre-whaling estimates. This data does not indicate any population-level impacts from decades of ongoing Navy training and testing in the Hawaiian Islands.

Comment 63: A commenter recommended additional mitigation areas critical habitat for the Main Hawaiian Islands insular false killer whale. NMFS issued the Final Rule designating critical habitat under the ESA on July 24, 2018. A commenter stated that in light of the 2018 listing under the ESA, NMFS must protect this species from the noise and other disturbance resulting from naval activities, including by mitigating impacts within its critical habitat. The commenter recommended that, at minimum, the Navy establish protective Start Printed Page 66903Mitigation Areas in all the BIAs identified for this species by NOAA and that NMFS should revisit and revise its Mitigation Areas and mitigation requirements based on the final critical habitat designation.

Response: Critical habitat includes waters from the 45 m depth contour to the 3,200 m depth contour around the main Hawaiian Islands from Niihau east to Hawaii (82 FR 51186). With regard to the analysis of the identified Biologically Important Areas for the Main Hawaiian Islands insular false killer whales, see Section K.3.3 (False Killer Whale Small and Resident Population Area: Main Hawaiian Island Insular stock). With regard to the identified threats to the species, see Section 3.7.2.2.7.5 (Species-Specific Threats) and specifically the documented incidental take by commercial fisheries (Bradford and Forney, 2016; Oleson et al., 2010; Reeves et al., 2009; West, 2016). NMFS has previously determined that Navy's current training and testing activities are not expected to have fitness consequences for individual Main Hawaiian Islands insular false killer whales and not likely to reduce the viability of the populations those individual whales represent.

The Navy is implementing the Hawaii Island Mitigation Area which encompassess all of the BIA for Main Hawaiian Islands insular false killer whales around that island, and the 4-Islands Region Mitigation Area (which captures approximately 40 percent of the BIAs in the 4-island area). As discussed in the Mitigation Areas in Hawaii section of this final rule, these mitigation areas are expected to significantly reduce impacts to this stock and its habitat.

Comment 64: Commenters recommended additional mitigation areas for important habitat areas off Oahu, Kauai, and Niihau—the waters off Oahu, Kauai, and Niihau include a number of important habitat areas for a variety of species, including false killer whale critical habitat (see above), five NOAA-identified BIAs off Oahu (false killer whale, humpback whale, pantropical spotted dolphin, bottlenose dolphin, and spinner dolphin) and three BIAs off Kauai and Niihau (humpback whale, spinner dolphin, and bottlenose dolphin) (Baird et al. 2012). The commenters assert that the agency must consider the implementation of Mitigation Areas off Oahu, Kau`i, and Niihau. Providing mitigation measures for select activities during even a limited season within some important habitat areas.

Response: In the HSTT FEIS/OEIS, the Navy considered the science, the Navy requirements, and the effectiveness of identified habitat areas off Oahu, Kauai, and Niihau as presented in Appendix K (Geographic Mitigation Assessment) Section K.3 (Biologically Important Areas within the Hawaii Range Complex Portion of the HSTT Study Area). This includes the five identified Biologically Important Areas off Oahu (false killer whale, humpback whale, pantropical spotted dolphin, bottlenose dolphin, and spinner dolphin) and three Biologically Important Areas off Kauai and Niihau (humpback whale, spinner dolphin, and bottlenose dolphin) as well as a discussion in Appendix K (Geographic Mitigation Assessment), Section K.1.1.5 (Mitigation Areas Currently Implemented) regarding the 4-Islands Region Mitigation Area.

Based on the Navy's analysis and as detailed in the sections referenced above, there is no scientific basis indicating the need for mitigation in the first place; see specifically the discussion in Appendix K (Geographic Mitigation Assessment), Section K.2.1.2 (Biological Effectiveness Assessment) of the HSTT FEIS/OEIS. As presented and reviewed in the HSTT FEIS/OEIS, the Navy has presented citations to research showing that in specific contexts (such as associated with urban noise, commercial vessel traffic, eco-tourism, or whale watching; see Chapter 3,Section 3.7.2.1.5.2 (Commercial Industries)) and references (Dunlop, 2016; Dyndo et al., 2015; Erbe et al., 2014; Frisk, 2012; Gedamke et al., 2016; Hermannsen et al., 2014; Li et al., 2015; McKenna et al., 2012; Melcón et al., 2012; Miksis-Olds and Nichols, 2015; Nowacek et al., 2015; Pine et al., 2016; Pirotta et al. 2018; Williams et al., 2014c) or specifically for Hawaii (Heenehan et al., 2016a, 2016b; Heenehan et al., 2017a, 2017b; Tyne et al., 2014; Tyne, 2015; Tyne et al., 2015; Tyne et al., 2017), that chronic repeated displacement and foraging disruption of populations with residency or high site fidelity can result in population-level effects. As also detailed in the HSTT FEIS/OEIS, the planned Navy training and testing activities do not equate with the types of disturbance in the citations above nor do they rise to the level of chronic disturbance where such effects have been demonstrated. There is no evidence to suggest there have been any population-level effects in the waters around Oahu, Kauai, and Niihau or in the HSTT Study Area resulting from the same training and testing activities that have been ongoing for decades, which the commenter recommends the need to stop, or at a minimum, be mitigated. In the waters around Oahu, Kauai, and Niihau, documented long-term residency by individuals and the existence of multiple small and resident populations precisely where Navy training and testing have been occurring for decades strongly suggests a lack of significant impact to those individuals and populations from the continuation of Navy training and testing. Appendix K of the HSTT FEIS/OEIS further describes the importance of these areas for Navy training and testing and why implementation of additional mitigation areas would be impracticable.

Comment 65: A commenter recommended additional mitigation area for Cross Seamount, as Cross Seamount represents important foraging habitat for a potentially rare or evolutionary distinct species of beaked whale, a commenter strongly recommended that the HSTT EIS/OEIS assess the designation of a year-round management area to protect the seamount. Such a designation would have secondary benefits for a variety of other odontocete species foraging at Cross Seamount seasonally between November and May. NMFS should also consider habitat-based management measures for other nearby seamounts.

Response: Analysis and consideration of Cross Seamount and “other nearby seamounts” for additional geographic mitigation was provided in Appendix K (Geographic Mitigation Assessment), Section K.7.1 (Hawaii Public Comment Mitigation Area Assessment), including sub-sections K.7.1.1 (General Biological Assessment of Seamounts in the Hawaii Portion of the Study Area) and K.7.1.2 (Cross Seamount) of the HSTT FEIS/OEIS.

As discussed in Appendix K (Geographic Mitigation Assessment), Section 4.7.1.3 (Mitigation Assessment) of the HSTT FEIS/OEIS, implementing new geographic mitigation measures in addition to ongoing procedural mitigation within the vicinity of Cross Seamount would not be effective at reducing adverse impacts on beaked whales or other marine mammal populations. The Navy has been training and testing in the broad ocean area around Cross Seamount with the same basic systems for over 40 years, and there is no evidence of any adverse impacts to marine species. Additionally, the suggested mitigation would not be practicable to implement. The broad ocean area around Cross Seamount and the seamounts to the north are unique in that there are no similar broad ocean areas in the vicinity of the Hawaiian Islands that are not otherwise Start Printed Page 66904encumbered by commercial vessel traffic and commercial air traffic routes. In addition, beaked whales may be more widely distributed than currently believed. Ongoing passive acoustic efforts from NMFS and Navy within the Pacific have documented beaked whale detections at many locations beyond slopes and seamounts to include areas over abyssal plains (Klinck et al. 2015, Griffiths and Barlow 2016, Rice et al., 2018).

Comment 66: A commenter commented that the NMFS must ensure that the activities are having the least practicable adverse impact, so it must do a comprehensive analysis of whether the proposed mitigation areas sufficiently protect marine mammals. NMFS must require the Navy to implement additional, practicable measures to mitigate further the adverse impacts of its activities. To ensure least practicable adverse impacts, NMFS must consider additional mitigation time/area restrictions, including but not limited to: (1) Expanded areas in Southern California to include all of the biologically important areas for whales; (2) add a Cuvier's beaked whale mitigation area in Southern California to protect that small, declining population that has high site fidelity; (3) add mitigation areas for the biologically important areas off of Oahu and Kauai; (4) the entire Humpback National Marine Sanctuary should be afforded protections from Navy activities because it is an important habitat for breeding, calving and nursing; and (5) limits on sonar and explosives should be adopted in the designated critical habitat for the Hawaiian monk seal and false killer whale.

Response: In regards to expanded areas in Southern California to include all of the biologically important areas for whales, the Navy has agreed to expanded areas in SOCAL, a portion of the San Nicholas Island BIA and the Santa Monica/Long Beach BIA are now included as part of the San Diego Arc Mitigation Area but also named the San Nicholas Island Mitigation Area and the Santa Monica/Long Beach Mitigation Area. The Santa Monica Bay/Long Beach and San Nicolas Island BIA only partially overlaps a small portion of the northern part of the SOCAL portion of the HSTT Study Area. The Santa Monica Bay/Long Beach BIA overlap in SOCAL is 13.9 percent. The San Nicolas Island BIA overlap in SOCAL is 23.5 percent.

The Navy will limit surface ship sonar and not exceed 200 hours of MFAS sensor MF1 June 1 through October 31 during unit-level training and MTEs in the Santa Monica Bay/Long Beach BIA and San Nicolas Island Mitigation Areas (as well as San Diego Arc Mitigation Area). The Navy has also agreed to limit explosives. Specifically, within the San Nicolas Island Mitigation Area, the Navy will not use explosives that could potentially result in the take of marine mammals during mine warfare, large-caliber gunnery, torpedo, bombing, and missile (including 2.75″ rockets) activities during training. Within the Santa Monica/Long Beach Mitigation Area, the Navy will not use explosives that could potentially result in the take of marine mammals during mine warfare, large-caliber gunnery, torpedo, bombing, and missile (including 2.75″ rockets) activities during training and testing.

The Tanner-Cortes Bank BIA—NMFS and the Navy have discussed this extensively, and the Navy is unable to incorporate this area into geographic mitigation because is impracticable. Specifically, it would not be practical for the Navy to implement and prevents the Navy from meeting training and testing missions. As discussed in detail in Appendix K (Geographic Mitigation Assessment) of the HSTT FEIS/OEIS, during the Navy's practicability and biological review of the Tanner Bank BIA, it was concluded that implementation of a mitigation area was not practical for this species. The area in and around Tanner Banks is a core high priority training and testing venue for SOCAL combining unique bathymetry and existing infrastructure. This includes an existing bottom training minefield adjacent to Tanner Banks, future Shallow Water Training Range (SWTR West) expansion as well as proximity to critical tactical maneuver areas to the south and the Navy's underwater instrumented range to the northeast. Furthermore, the general area is in or adjacent to critical Navy training that cannot occur at other locations due to available, existing infrastructure, operationally relevant bathymetry, sea space, proximity to San Clemente Island and San Diego, etc.). Of all the blue whale BIAs designated, the Tanner Banks BIA had the fewest blue whale sighting records supporting its designation. New science since designation funded by the Navy further highlights how infrequently Tanner Bank is used by blue whales as compared to the rest of their movements in SOCAL. Out of 73 blue whales tagged with satellite transmitters, only a few transits through Tanner Banks were documented between 2014-2017. The longest cumulative time any individual whale stayed within the boundaries of the Tanner Banks BIA was less than one and a half days. Typical average blue whale daily movement along the U.S. West Coast is often up to 13-27 nautical miles a day (Oregon State University, unpublished data). Most blue whale area restricted foraging occurred around the northern Channel Islands, north of and outside of the HSTT SOCAL Study Area.

The feeding areas as recommended by the commenter north of Los Angeles for humpbacks (Santa Barbara Channel-San Miguel BIA and Morro Bay to Pt Sal) and blue whales (Santa Barbara Channel to San Miguel BIA, Pt Conception/Arguello to Pt Sal) are outside of the HSTT Study Area; therefore are not applicable for inclusion.

In regard to adding a Cuvier's beaked whale mitigation area in Southern California to protect that small, declining population that has high site fidelity, NMFS is assuming the commenter is referring to the area west of San Clemente Island as the comment letter did not specify an exact location. The beaked whale species detected most frequently in Southern California is Cuvier's beaked whale. Cuvier's beaked whales are widely distributed within Southern California and across the Pacific with almost all suitable deep water habitat >800 m conceivably containing Cuvier's beaked whales. In new unpublished Navy funded data, beaked whales have even been detected over deep water, open abyssal plains (>14,000 feet). Only limited population vital rates exist for beaked whales, covering numbers of animals, populations vs. subpopulations determination, and residency time for individual animals. While Cuvier's beaked whales have been detected north and west of Tanner and Cortes Banks, as noted above this species is also detected in most all Southern California locations 800 m in depth. The Navy's Marine Mammal Monitoring on Navy Ranges (M3R) program has documented continual Cuvier's beaked whale presence on SOAR over 8-years from 2010-2017 with slight abundance increases through 2017 (DiMarzio et al., 2018.)

Navy-funded research on Cuvier's beaked whales within the Southern California (SOCAL) Range Complex began in 2006. In 2008, researchers began deploying satellite tags as a part of this research. To date, 27 Low- Impact Minimally-Percutaneous External-electronics Transmitting (LIMPET) tags have been deployed within the complex. Twenty-five of those whales were tagged within the San Nicolas Basin and two were tagged in the Catalina Basin. Average transmission duration was 36.6 days (sd Start Printed Page 66905= 29.8), with the longest transmitting for 121.3 days. Movement data suggest that Cuvier's beaked whales have a high degree of site-fidelity to the Southern California Range Complex, and the San Nicolas basin in particular. Overall, there were 3,207 filtered location estimates from the 27 tagged whales, 91 percent of which were within the SoCal Range Complex. 54 percent of all location estimates were within the San Nicolas Basin, with twelve tagged whales spending more than 80 percent of their transmission duration within the basin. The two whales tagged in the Catalina Basin never entered the San Nicolas Basin. Only three whales tagged in the San Nicolas Basin crossed into the Catalina Basin (1.3 percent of all locations); two of those whales had just one Catalina Basin location each, though the remaining whale had 28 percent of its locations there. Five whales tagged in the San Nicolas Basin moved into the Santa Cruz Basin for anywhere from 1-62 percent of their time (6 percent of all locations). In contrast, 20 of 25 whales tagged in the San Nicolas Basin moved south of the basin at some point. Of these 20 whales, most remained within either Tanner Canyon or the San Clemente Basin immediately to the south, but one traveled north to near San Miguel Island and four traveled south towards Guadalupe Island. Three of these whales have not been documented in the San Nicolas basin since, though to date at least six whales tagged in the San Nicolas Basin have been re-sighted there a year or more after the deployment. Additionally, one of the whales that was south of San Nicolas when the tag stopped transmitting has since been sighted three times since.

Given that there is the uncertainty of current residence of Cuvier's beaked whales in the areas north and west of SOAR, the fact that general occurrence of beaked whales in Southern California may not necessarily equate to factors typically associated with biologically important areas (i.e., one area not more important than another), and consideration of the importance of Navy training and testing in the areas around SOAR and Tanner and Cortes Banks as discussed in Appendix K (Geographic Mitigation Assessment), i.e., the impracticability of additional area mitigation in this area, additional geographic mitigation to create a “refuge” in the recommended area is not scientifically supported or warranted.

In regard to the comment on the entire Humpback Whale National Marine Sanctuary should be afforded protections from Navy activities because it is an important habitat for breeding, calving and nursing the Humpback National Marine Sanctuary largely overlaps both the Hawaii Island Mitigation Area as well as the 4-Islands Region Mitigation Area. In the Hawaii Island Mitigation Area (year-round), the Navy will not conduct more than 300 hours of MF1 surface ship hull-mounted mid-frequency active sonar or 20 hours of MF4 dipping sonar, or use explosives that could potentially result in takes of marine mammals during training and testing. In the 4-Islands Region Mitigation Area (November 15-April 15 for active sonar; year-round for explosives), the Navy will not use MF1 surface ship hull-mounted mid-frequency active sonar or explosives that could potentially result in takes of marine mammals during training and testing. This seasonal limitation is specifically during important breeding, calving, and nursing, times/habitat for humpback whales and was expanded for humpback whales as the previous season for this mitigation area was December 15-April 15).

There are areas of the Humpback Whale National Marine Sanctuary around the islands of Niihau, Kauai, Oahu, and west of Molokai (Penguin Bank) that are outside of the Navy's mitigation areas. However, none of the Navy's training and testing areas for explosives around Kauai and Niihau are within the Hawaiian Islands Humpback Whale National Marine Sanctuary. There may be limited sonar use as units transit to/from PMRF ranges.

Part of the Humpback Whale National Marine Sanctuary, west of the island of Molokai, Penguin Bank, is not included in the 4-Islands Region Mitigation Area. Penguin Bank particularly is used for shallow water submarine testing and anti-submarine warfare training because of its large expanse of shallow bathymetry. While submarines do not typically use mid-frequency active sonar, relying primarily on passive sonar (listening mode) to avoid detection from adversaries, submarines are required to train in counter detection tactics, techniques and procedures against threat surface vessels, airborne anti-submarine warfare units and other threat submarines using mid-frequency active sonar as part of both their perspective Commanding Officers qualification course and pre-deployment certification. The ability for surface vessels and air assets to simulate opposing forces, using mid-frequency active sonar when training with submarines, is critical to submarine crew training for deployed and combat operations. Surface ships and aircraft mimicking opposition forces present submarines with a realistic and complicated acoustic and tactical environment. The Navy expects real-world adversaries to target our submarines with active sonar. Without active sonar from opposition forces submarines do not get a realistic picture regarding if they successfully evaded detection. Surface warfare training is designed to support unit-level training requirements and group cross-platform events in 28 mission areas for surface ship certification prior to deployment.

Additionally, the Navy will implement the Humpback Whale Special Reporting Area (December 15 through April 15) is comprised of additional areas of high humpback whale densities that overlap the Humpback Whale National Marine Sanctuary. This reporting is included in the exercise and monitoring reports that are an ongoing Navy requirement and are submitted to NMFS annually. Special reporting data, along with all other reporting requirements, are considered during adaptive management to determine if additional mitigation may be required. The Navy currently reports to NMFS the total hours (from December 15 through April 15) of all hull-mounted mid-frequency active sonar usage occurring in the Humpback Whale Special Reporting Area, plus a 5 km buffer, but not including the Pacific Missile Range Facility. The Navy will continue this reporting for the Humpback Whale Special Reporting Area.

In regard to limits on sonar and explosives should be adopted in the ESA-designated critical habitat for the Hawaiian monk seal and false killer whale, the Navy will cap MFAS for the entire false killer whale BIA adjacent to the island of Hawaii and a portion of the false killer whale BIA north of Maui and Molokai as follows. The Navy already will to limit explosive use in the entire false killer whale BIA adjacent to the island of Hawaii. The Navy will now add year-round limitation on explosives to the 4-Islands Region Mitigation Area, which includes a portion of the false killer whale BIA north of Maui and Molokai. For the Hawaii Island Mitigation Area (year-round): The Navy will not conduct more than 300 hours of surface ship hull-mounted MFAS sonar MF1 (MF1) or 20 hours of MFAS dipping sonar MF4 (MF4), or use explosives during training and testing year-round. For the 4-Islands Region Mitigation Area (November 15-April 15 for active sonar, year-round for explosives): The Navy will not use surface ship hull-mounted MFAS sonar MF1 from November 15-April 15 and explosive year-round during training or Start Printed Page 66906testing activities. The remaining false killer whale BIA overlaps with areas (e.g., Kaiwi Channel) where additional mitigations were found to be impractical.

In regard to limits on sonar and explosives in ESA-designated critical habitat for Hawaiian monk seal, the Navy's training and testing activities do occur in a portion of the ESA-designated critical habitat for Hawaiian monk seals, which is of specific importance to the species. However, monk seals in the main Hawaiian Islands have increased while the Navy has continued its activities, even though the Hawaiian monk seal overall population trend has been on a decline from 2004 through 2013, with the total number of Hawaiian monk seals decreasing by 3.4 percent per year (Carretta et al., 2017). While the decline has been driven by the population segment in the northwestern Hawaiian Islands, the number of documented sightings and annual births in the main Hawaiian Islands has increased since the mid-1990s (Baker, 2004; Baker et al., 2016). In the main Hawaiian Islands, the estimated population growth rate is 6.5 percent per year (Baker et al., 2011; Carretta et al., 2017). Of note, in the 2013 HRC Monitoring Report, tagged monk seals did not show any behavioral changes during periods of MFAS.

The Hawaii Island Mitigation Area overlaps all of their critical habitat around the Island of Hawaii (as well as the southern end of Maui) and, by not using explosives or the most impactful sonar sources in this, thereby reduces the likelihood that take might impact reproduction or survival by interfering with important feeding or resting behaviors (potentially having adverse impacts on energy budgets) or separating mothers and pups in times when pups are more susceptible to predation and less able to feed or otherwise take care of themselves. The 4-Islands Mitigation Area overlaps with ESA-designated critical habitat around Maui, Lanai, and Molokai.

Comment 67: A commenter commented that in the proposed rule, NMFS estimates 588 takes annually will cause multiple instances of exposure to insular false killer whales, taking 400 percent of the population. As the potential biological removal is 0.18 animals, the loss of a single individual, or an impairment to its health and fitness, could place the species on an extinction trajectory. NMFS must consider additional mitigation in the designated critical habitat, as well as excluded areas, to ensure a negligible impact on false killer whales.

Response: The commenter is conflating behavioral take with mortality take addressed in PBR. There are no insular false killer whale mortality takes modeled, anticipated, or authorized. 400 percent of the population would mean that all animals would be behaviorally harassed an average of 4 times per year, or once per season. The short term biological reaction of an animal for periods of minutes to hours a few times a year would not have any fitness impacts to the individual let alone any population level impacts. NMFS confirms that these impacts are negligible. Additionally, much of the Navy's mitigations on Hawaii and the 4 island region encompass areas that overlap with high use insular false killer whale habitat and thus already mitigate impacts. From the Navy consultation with NMFS under the ESA for insular false killer whale critical habitat, less than 12 percent of modeled takes would take place in or near insular false killer whale critical habitat. These takes as explained previously would be transitory (short-duration), and spread out in time and space.”

Comment 68: A commenter recommended establishing stand-off distances around the Navy's mitigation areas to the greatest extent practicable, allowing for variability in size given the location of the area, the type of operation at issue, and the species of concern.

Response: Mitigation areas are typically developed in consideration of both the area that is being protected and the distance from the stressor in question that is appropriate to maintain to ensure the protection. Sometimes this results in the identification of the area plus a buffer, and sometimes both the protected area and the buffer are considered together in the designation of the edge of the area. We note that the edges of a protected area are typically of less importance to a protected stock or behavior, since important areas often have a density gradient that lessens towards the edge. Also, while a buffer of a certain size may be ideal to alleviate all impacts of concern, a lessened buffer does not mean that the protective value is significantly reduced, as the core of the area is still protected. Also, one should not assume that activities are constantly occurring in the area immediately adjacent to the protected area.

These issues were considered here, and the Navy has indicated that the mitigation identified in Chapter 5 (Mitigation), Section 5.4 (Mitigation Areas to be Implemented) of the HSTT FEIS/OEIS represents the maximum mitigation within mitigation areas and the maximum size of mitigation areas that are practicable to implement under the Proposed Action. The Navy has communicated (and NMFS concurs with the assessment) that implementing additional mitigation (e.g., stand-off distances that would extend the size of the mitigation areas) beyond what is described in Chapter 5 (Mitigation), Section 5.4 (Mitigation Areas to be Implemented) of the HSTT FEIS/OEIS would be impracticable due to implications for safety (the ability to avoid potential hazards), sustainability (based on the amount and type of resources available, such as funding, personnel, and equipment)), and the Navy's ability to continue meeting its Title 10 requirements.

Additional Mitigation Research

Comment 69: A commenter recommended NMFS consider additional mitigation measures to prescribe or research including: (1) Research into sonar signal modifications; (2) mitigation and research on Navy ship speeds (the commenter recommended that the agency require the Navy to collect and report data on ship speed as part of the EIS process); and (3) compensatory mitigation for the adverse impacts of the permitted activity on marine mammals and their habitat that cannot be prevented or mitigated.

Response: NMFS consulted with the Navy regarding potential research into additional mitigation measures and discussion is included below.

1. Research into sonar signal modification—Sonar signals are designed explicitly to provide optimum performance at detecting underwater objects (e.g., submarines) in a variety of acoustic environments. The Navy acknowledges that there is very limited data, and some suggest that up or down sweeps of the sonar signal may result in different animal reactions; however, this is a very small data sample, and this science requires further development. If future studies indicate this could be an effective approach, then NMFS and the Navy will investigate the feasibility and practicability to modify signals, based on tactical considerations and cost, to determine how it will affect the sonar's performance.

2. Mitigation and research on Navy ship speeds inclusive of Navy collecting and reporting data on ship speed as part of the EIS—The Navy conducted an operational analysis of potential mitigation areas throughout the entire Study Area to consider a wide range of mitigation options, including but not limited to vessel speed restrictions. As Start Printed Page 66907discussed in Chapter 3, Section 3.0.3.3.4.1 (Vessels and In-Water Devices) of the HSTT FEIS/OEIS, Navy ships transit at speeds that are optimal for fuel conservation or to meet operational requirements. Operational input indicated that implementing additional vessel speed restrictions beyond what is identified in Chapter 5 (Mitigation), Section 5.4 (Mitigation Areas to be Implemented) of the HSTT FEIS/OEIS would be impracticable to implement due to implications for safety and sustainability. In its assessment of potential mitigation, the Navy considered implementing additional vessel speed restrictions (e.g., expanding the 10 kn restriction to other activities). The Navy determined that implementing additional vessel speed restrictions beyond what is described in Chapter 5 (Mitigation), Section 5.5.2.2 (Restricting Vessel Speed) of the HSTT FEIS/OEIS would be impracticable due to implications for safety (the ability to avoid potential hazards), sustainability (maintain readiness), and the Navy's ability to continue meeting its Title 10 requirements to successfully accomplish military readiness objectives. Additionally, as described in Chapter 5 (Mitigation), Section 5.5.2.2 (Restricting Vessel Speed) of the HSTT FEIS/OEIS, any additional vessel speed restrictions would prevent vessel operators from gaining skill proficiency, would prevent the Navy from properly testing vessel capabilities, or would increase the time on station during training or testing activities as required to achieve skill proficiency or properly test vessel capabilities, which would significantly increase fuel consumption. As discussed in Chapter 5 (Mitigation), Section 5.3.4.1 (Vessel Movement) of the HSTT FEIS/OEIS, the Navy implements mitigation to avoid vessel strikes throughout the Study Area. As directed by the Chief of Naval Operations Instruction (OPNAVINST) 5090.1D, Environmental Readiness Program, Navy vessels report all marine mammal incidents worldwide, including ship speed. Therefore, the data required for ship strike analysis discussed in the comment is already being collected. Any additional data collection required would create an unnecessary and impracticable administrative burden on the Navy.

3. Compensatory mitigation—For years, the Navy has implemented a very broad and comprehensive range of measures to mitigate potential impacts to marine mammals from military readiness activities. As the HSTT FEIS/OEIS documents in Chapter 5 (Mitigation), the Navy is proposing to expand these measures further where practicable. Aside from direct mitigation, as noted by the commenter, the Navy engages in an extensive spectrum of other activities that greatly benefit marine species in a more general manner that is not necessarily tied to just military readiness activities. As noted in Chapter 3, Section 3.0.1.1 (Marine Species Monitoring and Research Programs) of the HSTT FEIS/OEIS, the Navy provides extensive investment for research programs in basic and applied research. The U.S. Navy is one of the largest sources of funding for marine mammal research in the world, which has greatly enhanced the scientific community's understanding of marine species much more generally. The Navy's support and marine mammal research includes: Marine mammal detection, including the development and testing of new autonomous hardware platforms and signal processing algorithms for detection, classification, and localization of marine mammals; improvements in density information and development of abundance models of marine mammals; and advancements in the understanding and characterization of the behavioral, physiological (hearing and stress response), and potentially population-level consequences of sound exposure on marine life. Compensatory mitigation is not required to be imposed upon Federal agencies under the MMPA. Importantly, the commenter did not recommend any specific measure(s), rendering it impossible to conduct any meaningful evaluation of its recommendation. Finally, many of the methods of compensatory mitigation that have proven successful in terrestrial settings (purchasing or preserving land with important habitat, improving habitat through plantings, etc.) are not applicable in a marine setting with such far-ranging species. Thus, any presumed conservation value from such an idea would be purely speculative at this time.

Comment 70: A commenter recommended that given the paucity of information on marine mammal habitat currently available for the HSTT Study Area, that efforts be undertaken in an iterative manner by NMFS, and the Navy, to identify additional important habitat areas across the HSTT Study Area, using the full range of data and information available to the agencies (e.g., habitat-based density models, NOAA-recognized BIAs, survey data, oceanographic and other environmental data, etc.).

Response: NMFS and the Navy used the best available scientific information (e.g., SARs and numerous study reports from Navy-funded monitoring and research in the specific geographic region) in assessing density, distribution, and other information regarding marine mammal use of habitats in the HSTT Study Area. In addition, NMFS consulted LaBrecque et al. (2015), which provides a specific, detailed assessment of known BIAs, which may be region-, species-, and/or time-specific, include reproductive areas, feeding areas, migratory corridors, and areas in which small and resident populations are concentrated. While the science of marine mammal occurrence, distribution, and density resides as a core NMFS mission, the Navy does provide extensive support to the NMFS mission via ongoing HSTT specific monitoring as detailed in this final rule. Also included are direct Navy funding support to NMFS for programmatic marine mammal surveys in Hawaii and the U.S. West Coast, and spatial habitat model improvements.”

Comment 71: A commenter recommended integration of important habitat areas to improve resolution of operations. The delineation of BIAs by NOAA, the updates made by the Navy to its predictive habitat models, and evidence of additional important habitat areas within the HSTT Study Area, provide the opportunity for the agencies to improve upon their current approach to the development of alternatives by improving resolution of their analysis of operations. A commenter offered the following thoughts for consideration.

They state that recognizing that important habitat areas imply the non-random distribution and density of marine mammals in space and time, both the spatial location and the timing of training and testing events in relation to those areas is a significant determining factor in the assessment of acoustic impacts. Levels of acoustic impact derived from the NAEM are likely to be under- or over-estimated depending on whether the location of the modeled event is further from the important habitat area, or closer to it, than the actual event. Thus, there is a need for the Navy to compile more information regarding the number, nature, and timing of testing and training events that take place within, or in close proximity to, important habitat areas, and to refine its scale of analysis of operations to match the scale of the habitat areas that are considered to be important. While the proposed rule, in assessing environmental impacts on marine mammals, breaks down estimated impacts by general region (i.e., HRC and SOCAL), the resolution is seldom greater than range complex or Start Printed Page 66908homeport and is not specifically focused on areas of higher biological importance. Current and ongoing efforts to identify important habitat areas for marine mammals should be used by NMFS and by the Navy as a guide to the most appropriate scale(s) for the analysis of operations.

Response: In their take request and effects analysis provided to NMFS, the Navy considered historic use (number and nature of training and testing activities) and locational information of training and testing activities when developing modelling boxes. The timing of training cycles and testing needs varies based on deployment requirements to meet current and emerging threats. Due to the variability, the Navy's description of its specified activities is structured to provide flexibility in training and testing locations, timing, and number. In addition, information regarding the exact location of sonar usage is classified. Due to the variety of factors, many of which influence locations that cannot be predicted in advance (e.g., weather), the analysis is completed at a scale that is necessary to allow for flexibility. The purpose of the Navy's quantitative acoustic analysis is to provide the best estimate of impact/take to marine mammals and ESA listed species for the regulatory and ESA section 7 consultation analyses. Specifically, the analysis must take into account multiple Navy training and testing activities over large areas of the ocean for multiple years; therefore, analyzing activities in multiple locations over multiple seasons produces the best estimate of impacts/take to inform the HSTT FEIS/OEIS and regulators. Also, the scale at which spatially explicit marine mammal density models are structured is determined by the data collection method and the environmental variables that are used to build the model. Therefore, altogether, given the variables that determine when and where the Navy trains and tests, as well as the resolution of the density data, the analysis of potential impacts is scaled to the level that the data fidelity will support. NMFS has worked with the Navy over the years to increase the spatio-temporal specificity of the descriptions of activities planned in or near areas of biological importance, when possible (e.g., in BIAs or Sanctuaries, where possible), and NMFS is confident that the granularity of information provided sufficiently allows for an accurate assessment of both the impacts of the Navy's activities on marine mammal populations and the protective measures evaluated to mitigate those impacts.

Monitoring Recommendations

Comment 72: A commenter recommended that NMFS require that the Navy continue to conduct long-term monitoring with the aim to provide baseline information on occurrence, distribution, and population structure of marine mammal species and stocks, and baseline information upon which the extent of exposure to disturbance from training and testing activities at the individual, and ultimately, population level-impacts, and the effectiveness of mitigation measures, can be evaluated. The commenter recommended individual-level behavioral-response studies, such as focal follows and tagging using DTAGs, carried out before, during, and after Navy training and testing activities. The commenter recommended prioritizing DTAG studies that further characterize the suite of vocalizations related to social interactions. The commenter recommends the use of unmanned aerial vehicles. The commenter recommended that NMFS require the Navy to use these technologies for assessing marine mammal behavior before, during, and after Navy training and testings (e.g., swim speed and direction, group cohesion). Additionally, the commenter recommended studies into how these technologies can be used to assess body condition be supported as this can provide an important indication of energy budget and health, which can inform the assessment of population-level impacts.

Response: Broadly speaking, NMFS works closely with the Navy in the identification of monitoring priorities and the selection of projects to conduct, continue, modify, and/or stop through the Adaptive Management process, which includes annual review and debriefs by all scientists conducting studies pursuant to the Navy's MMPA rule. The process NMFS and the Navy have developed allows for comprehensive and timely input from the Navy and other stakeholders that is based on rigorous reporting out from the Navy and the researchers doing the work. Further, the Navy is pursuing many of the topics that the commenter identifies, either through the Navy monitoring required under the MMPA and ESA, or through Navy-funded research programs (ONR and LMR). We are confident that the monitoring conducted by the Navy satisfies the requirements of the MMPA.

The Navy established the Strategic Planning Process under the marine species monitoring program to help structure the evaluation and prioritization of projects for funding. Chapter 5 (Mitigation), Section 5.1.2.2.1.3 (Strategic Planning Process) of the HSTT FEIS/OEIS provides a brief overview of the Strategic Planning Process. More detail, including the current intermediate scientific objectives, is available on the monitoring portal as well as in the Strategic Planning Process report. The Navy's evaluation and prioritization process is driven largely by a standard set of criteria that help the steering committee evaluate how well a potential project would address the primary objectives of the monitoring program. NMFS has opportunities to provide input regarding the Navy's intermediate scientific objectives as well as providing feedback on individual projects through the annual program review meeting and annual report. For additional information, please visit: https://www.navymarinespeciesmonitoring.us/​about/​strategic-planning-process/​.

Details on the Navy's involvement with future research will continue to be developed and refined by the Navy and NMFS through the consultation and adaptive management processes, which regularly consider and evaluate the development and use of new science and technologies for Navy applications. The Navy has indicated that it will continue to be a leader in funding of research to better understand the potential impacts of Navy training and testing activities and to operate with the least possible impacts while meeting training and testing requirements.

(1) Individual-level behavioral-response studies—In addition to the Navy's marine species monitoring program investments for individual-level behavioral-response studies, the Office of Naval Research Marine Mammals and Biology program and the Navy's Living Marine Resources program continue to heavily invest in this topic. For example, the following studies are currently being funded:

  • The Southern California Behavioral Response Study (Principal Investigators: John Calambokidis and Brandon Southall)
  • Cuvier's Beaked Whale and Fin Whale Behavior During Military Sonar Operations: Using Medium-term Tag Technology to Develop Empirical Risk Functions (Principal Investigators: Greg Schorr and Erin Falcone)
  • 3S3-Behavioral responses of sperm whales to naval sonar (Principal Investigators: Petter Kvadsheim and Frans-Peter Lam)
  • Measuring the effect of range on the behavioral response of marine mammals through the use of Navy sonar (Principal Investigators: Stephanie Watwood and Greg Schorr)Start Printed Page 66909
  • Behavioral response evaluations employing robust baselines and actual Navy training (BREVE) (Principal Investigators: Steve Martin, Tyler Helble, Len Thomas)
  • Integrating remote sensing methods to measure baseline behavior and responses of social delphinids to Navy sonar (Principal Investigators: Brandon Southall, John Calambokidis, John Durban).

(2) DTAGS to characterize social communication between individuals of a species or stock, including mothers and calves. Furthermore, DTAGs are just one example of animal movement and acoustics tag. From the Navy's Office of Naval Research and Living Marine Resource programs, Navy funding is being used to improve a suite of marine mammal tags to increase attachment times, improve data being collected, and improve data satellite transmission—The Navy has funded a variety of projects that are collecting data that can be used to study social interactions amongst individuals. Examples of these projects include:

  • Southern California Behavioral Response Study (Principal Investigators: John Calambokidis and Brandon Southall)
  • Tagging and Tracking of Endangered North Atlantic Right Whales in Florida Waters (Principal Investigators: Doug Nowacek and Susan Parks). This project involves the use of DTAGs, and data regarding the tagged individual and group are collected in association with the tagging event. In addition to the vocalization data that is being collected on the DTAGs, data is collected on individual and group behaviors that are observed, including between mother/calf pairs when applicable. The Navy will continue to collect this type of data when possible.
  • Integrating remote sensing methods to measure baseline behavior and responses of social delphinids to Navy sonar (Principal Investigators: Brandon Southall, John Calambokidis, John Durban)
  • Acoustic Behavior of North Atlantic Right Whale (Eubalaena glacialis) Mother-Calf Pairs (Principal Investigators: Susan E. Parks and Sofie Van Parijs). The long-term goal of this project is to quantify the behavior of mother-calf pairs from the North Atlantic right whale to determine: a) why mothers and calves are more susceptible to collisions with vessels and b) the vocal behavior of this critical life stage to assess the effectiveness of passive acoustic monitoring to detect mother-calf pairs in important habitat areas (see https://www.onr.navy.mil/​reports/​FY15/​mbparks.pdf).
  • Social Ecology and Group Cohesion in Pilot Whales and Their Responses to Playback of Anthropogenic and Natural Sounds (Principal Investigator: Frants H. Jensen). This project investigates the social ecology and cohesion of long-finned pilot whales as part of a broad multi-investigator research program that seeks to understand how cetaceans are affected by mid-frequency sonar and other sources of anthropogenic noise (see https://www.onr.navy.mil/​reports/​FY15/​mbjensen.pdf).

(3) Unmanned Aerial Vehicles to assess marine mammal behavior before, during, and after Navy training and testing activities (e.g., swim speed and direction, group cohesion)—Studies that use unmanned aerial vehicles to assess marine mammal behaviors and body condition are being funded by the Office of Naval Research Marine Mammals and Biology program. Although the technology shows promise, the field limitations associated with the use of this technology has hindered the useful application in behavioral response studies in association with Navy training and testing events. For safety, research vessels cannot remain in close proximity to Navy vessels during Navy training or testing events, so battery life of the unmanned aerial vehicles has been an issue. However, as the technology improves, the Navy will continue to assess the applicability of this technology for the Navy's research and monitoring programs. An example project is Integrating Remote Sensing Methods to Measure Baseline Behavior and Responses of Social Delphinids to Navy sonar (Principal Investigators: Brandon Southall, John Calambokidis, and John Durban).

(4) NMFS asked the Navy to expand funding to explore the utility of other, simpler modeling methods that could provide at least an indicator of population-level effects, even if each of the behavioral and physiological mechanisms are not fully characterized—The Office of Naval Research Marine Mammals and Biology program has invested in the Population Consequences of Disturbance (PCoD) model, which provides a theoretical framework and the types of data that would be needed to assess population level impacts. Although the process is complicated and many species are data poor, this work has provided a foundation for the type of data that is needed. Therefore, in the future, relevant data that is needed for improving the analytical approaches for population level consequences resulting from disturbances will be collected during projects funded by the Navy's marine species monitoring program. General population level trend analysis is conducted by NMFS through its stock assessment reports and regulatory determinations. The Navy's analysis of effects to populations (species and stocks) of all potentially exposed marine species, including marine mammals and sea turtles, is based on the best available science as discussed in Sections 3.7 (Marine Mammals) and 3.8 (Reptiles) of the HSTT FEIS/OEIS. PCoD models, similar to many fisheries stock assessment models, once developed will be powerful analytical tools when mature. However, currently they are dependent on too many unknown factors for these types of models to produce a reliable answer. As discussed in the Monitoring section of the final rule, the Navy's marine species monitoring program typically supports 10-15 projects in the Atlantic at any given time. Current projects cover a range of species and topics from collecting baseline data on occurrence and distribution, to tracking whales and sea turtles, to conducting behavioral response studies on beaked whales and pilot whales. The Navy's marine species monitoring web portal provides details on past and current monitoring projects, including technical reports, publications, presentations, and access to available data and can be found at: https://www.navymarinespeciesmonitoring.us/​regions/​atlantic/​current-projects/​. A list of the monitoring studies that the Navy is currently planning under this rule are listed at the bottom of the Monitoring section of this final rule.

Negligible Impact Determination

General

Comment 73: Commenters commented that NMFS' analytical approach for negligible impact determination is not transparent and that the methods and resulting data cannot be substantiated with the information provided. The Commission stated that in general, NMFS has based negligible impact determinations associated with incidental take authorizations on abundance estimates provided either in its Stock Assessment Reports (SARs) or other more recent published literature. For the HSTT proposed rule, NMFS used abundance estimates as determined by the Navy's underlying density estimates rather than abundance estimates from either the SARs or published literature. NMFS did also not specify how it determined the actual abundance given that many of the densities differ on orders of kilometers. Interpolation or smoothing, and potentially extrapolation, of data likely would be necessary to achieve NMFS' intended goal—it is unclear whether any such methods were implemented. In addition, it is unclear whether NMFS estimated the abundances in the same manner beyond the U.S. EEZ as it did within the U.S. EEZ for HRC and why it did not compare takes within the U.S. EEZ and beyond the U.S. EEZ for Start Printed Page 66910SOCAL, given that a larger proportion of the Navy's SOCAL action area is beyond the U.S. EEZ than HRC. Furthermore, NMFS did not specify how it determined the proportion of total takes that would occur beyond the U.S. EEZ. Moreover, the `instances' of the specific types of taking (i.e., mortality, Level A and B harassment) do not match the total takes `inside and outside the EEZ' in Tables 69-81 (where applicable) or those take estimates in Tables 41-42 and 67-68. It also appears the `instances' of take columns were based on only those takes in the U.S. EEZ for HRC rather than the area within and beyond the U.S. EEZ. It further is unclear why takes were not apportioned within and beyond the U.S. EEZ for SOCAL. Given that the negligible impact determination is based on the total taking in the entire study area, NMFS should have partitioned the takes in the `instances' of take columns in Tables 69-81 for all activities that occur within and beyond the U.S. EEZ. One commenter further asserts that any “small numbers” determination that relies on abundance estimates derived simplistically from modeled densities is both arbitrary and capricious. The commenters assert that NMFS should, at least for data rich species, derive its absolute abundance estimates from NMFS' SARs or more recently published literature.

Response: NMFS' Analysis and Negligible Impact Determination section has been updated and expanded in the final rule to clarify the issues the Commenters raise here (as well as others). Specifically, though, NMFS uses both the Navy-calculated abundance (based on the Navy-calculated densities described in detail in the Estimated Take of Marine Mammal section) and the SARs abundances, where appropriate, in the negligible impact analysis—noting that the nature of the overlap of the Navy Study Area with the U.S. EEZ is different in Hawaii versus SOCAL, supporting different analytical comparisons.

NMFS acknowledges that there were a few small errors in the take numbers in the proposed rule; however, they have been corrected (i.e., the take totals in Tables 41 and 42 for a given stock now equal the “in and outside the U.S. EEZ” take totals in Tables X-Y) and the minor changes do not affect the analysis or determinations in the rule.

Also, the Commenters are incorrect that the instances of take for HRC do not reflect the take both within and outside the U.S. EEZ. They do. Last, one commenter mentions the agency making a “small numbers” determination, but such a determination is not applicable in the context of military readiness activities.

Comment 74: A commenter commented that the activities proposed by the Navy include high-intensity noise pollution, vessel traffic, explosions, pile driving, and more at a massive scale. According to the commenter, NMFS has underestimated the amount of take and the adverse impact that it will have on marine mammals and their habitat.

Response: NMFS has provided extensive information demonstrating that the best available science has been used to estimate the amount of take, and further to analyze the impacts that all of these takes combined will have on the affected species and stocks. As described in the Analysis and Negligible Impact Determination section, this information and our associated analyses support the negligible impact determinations necessary to issue these regulations.

Comment 75: A commenter commented that blue whales exposed to mid-frequency sonar (with received levels of 110 to 120 dB re 1 μPa) are less likely to produce calls associated with feeding behavior. They cite the Goldbogen et al. (2013) study (and a subsequent study) as extremely concerning because of the potential impacts of sonar on the essential life functions of blue whales as it found that sonar can disrupt feeding and displace blue whales from high-quality prey patches, significantly impacting their foraging ecology, individual fitness, and population health. They also state that mid-frequency sonar has been associated with several cases of blue whale stranding events and that low-frequency anthropogenic noise can mask calling behavior, reduce communication range, and damage hearing. These impacts from sonar on blue whales suggest that the activities' impacts would have long-term, non-negligible impacts on the blue whale population.

Response: As described in this final rule in the Analysis and Negligible Impact Determination section, NMFS has fully considered the effects that exposure to sonar can have on blue whales, including impacts on calls and feeding and those outlined in the Goldbogen study. However, as discussed, any individual blue whale is not expected to be exposed to sonar and taken on more than several days per year. Thus, while vocalizations may be impacted or feeding behaviors temporarily disrupted, this small scale of impacts is not expected to affect reproductive success or survival of any individuals, especially given the limitations on sonar and explosive use within blue whale BIAs. Of additional note, while the blue whale behavioral response study (BRS) in Southern California documented some foraging responses by blue whales to simulated Navy sonar, any response was highly variable by individual and context of the exposure. There were, for instance, some individual blue whales that did not respond. Recent Navy-funded blue whale tracking has documented wide ranging movements through Navy areas such that any one area is not used extensively for foraging. More long-term blue whale residency occurs north of and outside of the HSTT Study Area. Further, we disagree with the assertion that MFAS has been causally associated with blue whale strandings. This topic was discussed at length in the proposed rule and there is no data causally linking MFAS use with blue whale strandings.

Comment 76: A commenter commented that NMFS cannot consider the additional mortality/serious injury, including the 0.2 in the proposed authorization for ship strike for blue whales, to have a negligible impact determination for this stock. They also state that counts of mortality/serious injury do not account for the additional takes proposed to be authorized that cumulatively can have population level impacts from auditory injury and behavioral disturbance. Similarly, the commenter commented that NMFS cannot consider the proposed authorization for 0.4 annual mortality/serious injury to have a negligible impact on the CA/OR/WA stock of humpback whales because take is already exceeding the potential biological removal, and especially concerning is any take authorized for the critically endangered Central America population that would have significant adverse population impacts.

Response: As described in detail in the Estimated Take of Marine Mammals section, the Navy and NMFS have revisited and re-analyzed the Navy's initial request for takes by mortality of blue and humpback whales from vessel strike and determined that only 1 strike of either would be anticipated over the course of 5 years, and therefore authorized the lesser amount. Further, NMFS has expanded and refined the discussion of mortality take, PBR, and our negligible impact finding in the Serious Injury and Mortality sub-section of the Analysis and Negligible Impact Determination section and do not repeat it here.

Comment 77: A commenter commented that the estimated Start Printed Page 66911population size for the Hawaii stock of sei whales is only 178 animals, and the potential biological removal is 0.2 whales per year. According to the Commenters, NMFS admits that the mortality for the Hawaii stock of sei whales is above potential biological removal. The commenter asserted that the conclusion that the action will have a negligible impact on this stock is arbitrary and capricious.

Response: As described in detail in the Estimated Take of Marine Mammals section, the Navy and NMFS revisited and re-analyzed the Navy's initial request for the take of a sei whale from vessel strike and determined that this take is unlikely to occur and, therefore, it is not authorized.

Comment 78: A commenter commented that any take of Hawaiian monk seal by the proposed activities will have a non-negligible impact given the precarious status of this species.

Response: NMFS' rationale for finding that the Navy's activity will have a negligible impact on monk seals is included in the Pinniped subsection of the Analysis and Negligible Impact Determination section and is not re-printed here. Nonetheless we reiterate that no mortality or injury due to tissue damage is anticipated or authorized, only one instance of PTS is estimated and authorized, and no individual monk seal is expected to be exposed to stressors that would result in take more than a few days a year. Further, the Hawaii Island and 4-Island mitigation areas provide significant protection of monk seal critical habitat in the Main Hawaiian Islands, reducing impacts form sonar and explosives around a large portion of pupping beaches and foraging habitat, as described in the Mitigation Measures section.

Cumulative and Aggregate Effects

Comment 79: One commenter asserted that NMFS has not apparently considered the impact of Navy activities on a population basis for many of the marine mammal populations within the HSTT Study Area. Instead, it has lodged discussion for many populations within broader categories, most prominently “mysticetes” (14 populations) and “odontocetes” (37 populations), that in some cases correspond to general taxonomic groups. Such grouping of stocks elides important differences in abundance, demography, distribution, and other population-specific factors, making it difficult to assume “that the effects of an activity on the different stock populations” are identical. That is particularly true where small, resident populations are concerned, and differences in population abundance, habitat use, and distribution relative to Navy activities can be profoundly significant. Additionally, the commenter states that NMFS assumed that all of the Navy's estimated impacts would not affect individuals or populations through repeated activity—even though the takes anticipated each year would affect the same populations and, indeed, would admittedly involve extensive use of some of the same biogeographic areas.

Response: NMFS provides information regarding broader groups in order to avoid repeating information that is applicable across multiple species or stocks, but analyses have been conducted and determinations made specific to each stock. The method used to avoid repeating information applicable to a number of species or stocks while also presenting and integrating all information applicable to particular species or stocks is described in the rule. Also, NMFS' analysis does address the fact that some individuals may be repeatedly impacted and how those impacts may or may not accrue to more serious effects. The Analysis and Negligible Impacts Determination section has been expanded and refined to better explain this.

Comment 80: NMFS' negligible impact analysis for Cuvier's beaked whales is predicated on a single take estimate for the CA/OR/WA stock. This is deeply problematic as the species is known to occur in small, resident populations within the SOCAL Range Complex. These populations are acutely vulnerable to Navy sonar. Cuvier's beaked whales have repeatedly been associated with sonar-related pathology, are known to react strongly to sonar at distances up to 100 kilometers, and are universally regarded to be among the most sensitive of all marine mammals to anthropogenic noise (Falcone et al., 2017). Some populations, such as the one in San Nicholas Basin that coincides with the Navy's much-used Southern California ASW Range (SOAR), are repeatedly exposed to sonar, posing the same risk of population-wide harm documented on a Navy range in the Bahamas (Falcone and Schorr, 2013). The broad take estimates presented in the Proposed Rule, and the negligible impact analysis that they are meant to support, provide no insight into the specific impacts proposed for these small populations.

Response: NMFS acknowledges the sensitivity of small resident populations both in our analyses and in the identification of mitigation measures, where appropriate. However, we are required to make our negligible impact determination in the context of the MMPA-designated stock, which, in the case of the CA/OR/WA stock of Cuvier's beaked whale, spans the U.S. EEZ off the West Coast. As described in our responses to previous comments, NMFS and the Navy have fully accounted for the sensitivity of Cuvier's beaked whales in the behavioral thresholds and the estimation of take. Further, contrary to the assertions of the commenter, NMFS has absolutely considered the potential impacts of repeated takes on individuals that show site fidelity and that analysis can be found in the Analysis and Negligible Impact Determination section, which has been refined and updated since the proposed rule based on public input. Nonetheless, in 2018, an estimate of overall abundance of Cuvier's beaked whales at the Navy's instrumented range in San Nicolas Basin was obtained using new dive-counting acoustic methods and an archive of passive acoustic M3R data representing 35,416 hours of data (DiMarzio, 2018; Moretti, 2017). Over the seven-year period from 2010-2017, there was no observed decrease and perhaps a slight increase in annual Cuvier's beaked whale abundance within San Nicolas Basin (DiMarzio, 2018). There does appear to be a repeated dip in population numbers and associated echolocation clicks during the fall centered around August and September (Moretti 2017, DiMarzio 2018). A similar August and September dip was noted by researchers using stand-alone off-range bottom passive acoustic devices in Southern California (Širović et al., 2016; Rice et al., 2017). This dip in abundance may be tied to some as yet unknown population dynamic or oceanographic and prey availability dynamics.

Comment 81: One commenter asserted that with respect to mortalities and serious injuries, NMFS' application of potential biological removal (PBR) is unclear and may not be consistent with its prior interpretations. The agency recognizes that PBR is a factor in determining whether the negligible impact threshold has been exceeded, but argues that, since PBR and negligible impact are different statutory standards, NMFS might find that an activity that kills marine mammals beyond what PBR could support would not necessarily exceed the negligible impact threshold. Regardless, however, of whether Congress intended PBR as a formal constraint on NMFS' ability to issue incidental take permits under section 101(a)(5), NMFS' own definition of “negligible impact” prevents it from authorizing mortalities or other takes that would threaten the sustainability of Start Printed Page 66912marine mammal stocks. Mortalities and serious injuries exceeding potential biological removal levels would do just that.

Additionally, in assessing the consequences of authorized mortality below PBR, NMFS applies an “insignificance” standard, such that any lethal take below 10 percent of residual PBR is presumed not to exceed the negligible impact threshold. This approach seems inconsistent, however, with the regulatory thresholds established for action under the commercial fisheries provision of the Act, where bycatch of 1 percent of total PBR triggers mandatory take reduction procedures for strategic marine mammal stocks. See 16 U.S.C. 1387(f)(1); 83 FR 5349, 5349 (Feb. 7, 2018). NMFS should clarify why it has chosen 10 percent rather than, for example, 1 percent as its “insignificance” threshold, at least for endangered species and other populations designated as strategic under the MMPA.

Response: NMFS disagrees that the consideration of PBR is unclear and notes that the narrative describing the application of PBR has been updated in this final rule to further explain how the agency considers this metric in the context of the negligible impact determination under section 101(a)(5)(A) (see the Serious Injury and Mortality sub-section of the Analysis and Negligible Impact Determination section) and is not repeated here. That discussion includes how PBR is calculated and therefore how it is possible for anticipated M/SI to exceed PBR or residual PBR and yet not adversely affect a particular species or stock through effects on annual rates of recruitment and survival.

Regarding the insignificance threshold, as explained in the rule, residual PBR is a metric that can be used to inform the assessment of M/SI impacts, and the insignificance threshold is an analytical tool to help prioritize analyst effort. But the insignificance threshold is not applied as a strict presumption as described by the commenter. Although it is true that as a general matter M/SI that is less than 10 percent of residual PBR should have no effect on rates of recruitment or survival, the agency will consider whether there are other factors that should be considered, such as whether an UME is affecting the species or stock.

The 10 percent insignificance threshold is an analytical tool that indicates that the potential mortality or serious injury is an insignificant incremental increase in anthropogenic mortality and serious injury that alone (in the absence of any other take and any other unusual circumstances) would clearly not affect rates of recruitment or survival. As such, potential mortality and serious injury at the insignificance-threshold level or below is evaluated in light of other relevant factors (such as an ongoing UME) and then considered in conjunction with any anticipated Level A or Level B harassment take to determine if the total take would affect annual rates of recruitment or survival. Ten percent was selected because it corresponds to the insignificance threshold under the MMPA framework for authorizing incidental take of marine mammals resulting from commercial fisheries. There the insignificance threshold, which also is 10 percent of PBR, is “the upper limit of annual incidental mortality and serious injury of marine mammal stocks by commercial fisheries that can be considered insignificant levels approaching a zero mortality and serious injury rate” (see 50 CFR 229.2). A threshold that represents an insignificant level of mortality or serious injury approaching a zero mortality and serious injury rate was thought to be an appropriate level to indicate when, absent other factors, the agency can be confident that expected mortality and serious injury will not affect annual rates of recruitment and survival, without the need for significant additional analysis.

Regarding the claim that NMFS' interpretation of PBR may be inconsistent with prior interpretations, we disagree. Rather, NMFS' interpretation of PBR has been utilized appropriately within the context of the different MMPA programs and associated statutory standards it has informed. The application of PBR under section 101(a)(5)(A) also has developed and been refined in response to litigation and as the amount of and nature of M/SI requested pursuant to this section has changed over time, thereby calling for the agency to take a closer look at how M/SI relative to PBR relates to effects on rates of recruitment and survival. Specifically, until recently, NMFS had used PBR relatively few times to support determinations outside of the context of MMPA commercial fisheries assessments and decisions. Indeed, in Georgia Aquarium, Inc. v. Pritzker, 135 F. Supp.3d 1280 (N.D. Ga. 2015), in ruling on a lawsuit in which the plaintiffs sought to use PBR as the reason they should be allowed to import animals from the Sahklin-Amur stock of beluga whales for public display, the Court summarized a “handful” of cases where NMFS had used PBR to support certain agency findings. The Court agreed that the agency does not have a “practice and policy” of applying PBR in all circumstances. Importantly, the Court stated that “NMFS has shown that where the Agency has considered PBR outside of the U.S. commercial fisheries context, it has treated PBR as only one `quantitative tool' and that it is not used as the sole basis for its impact analyses,” just as NMFS has done here for its negligible impact analyses.

The examples considered by the Georgia Aquarium Court involved scientific research permits or subsistence harvest decisions where reference to PBR was one consideration among several. Thus, in one of the examples referenced by the Court, PBR was included to evaluate different alternatives in a 2007 EIS developed in support of future grants and permits related to research on northern fur seals and Steller sea lions (available at https://repository.library.noaa.gov/​view/​noaa/​17331). Similarly, in the 2015 draft EIS on the Makah Tribe's request to hunt gray whales, different levels of harvest were compared against PBR along with other considerations in the various alternatives (available at https://www.westcoast.fisheries.noaa.gov/​publications/​protected_​species/​marine_​mammals/​cetaceans/​gray_​whales/​makah_​deis_​feb_​2015.pdf). Consistent with what the Georgia Aquarium Court found, in both of those documents PBR was one consideration in developing alternatives for the agency's EIS and not determinative in any decision-making process.

After 2013 in response to an incidental take authorization request from NMFS' Southwest Fisheries Science Center that contained PBR analysis and more particularly in response to a District Court's March 2015 ruling that NMFS' failure to consider PBR when evaluating lethal take under section 101(a)(5)(A) violated the requirement to use the best available science (see Conservation Council for Hawaii v. National Marine Fisheries Service, 97 F. Supp.3d 1210 (D. Haw. 2015)), NMFS began to systematically consider the role of PBR when evaluating the effects of M/SI during section 101(a)(5)(A) rulemakings. Previously, in 1996 shortly after the PBR metric was first introduced, NMFS denied a request from the U.S. Coast Guard for an incidental take authorization for their vessel and aircraft operations, seemingly solely on the basis of the potential for ship strike in relation to PBR. The decision did not appear to consider other factors that might also have informed the potential Start Printed Page 66913for ship strike of a North Atlantic right whale in relation to the negligible impact standard.

During the following years and until the Court's decision in Conservation Council and the agency issuing the proposed incidental take authorization for the Southwest Fisheries Science Center, NMFS issued incidental take regulations without referencing PBR. Thereafter, however, NMFS began considering and articulating the appropriate role of PBR when processing incidental take requests for M/SI under section 101(a)(5)(A). Consistent with the interpretation of PBR across the rest of the agency, NMFS' Permits and Conservation Division has been using PBR as a tool to inform the negligible impact analysis under section 101(a)(5)(A), recognizing that it is not a dispositive threshold that automatically determines whether a given amount of M/SI either does or does not exceed a negligible impact on the affected species or stock.

Comment 82: A commenter commented that NMFS failed to adequately assess the aggregate effects of all of the Navy's activities included in the rule. The commenter alleges that NMFS' lack of analysis of these aggregate impacts, which is essential to any negligible impact determination, represents a glaring omission from the proposed rule. While NMFS states that Level B behavioral harassment (aside from those caused by masking effects) involves a stress response that may contribute to an animal's allostatic load, it assumes without further analysis that any such impacts would be insignificant.

Response: NMFS did analyze the potential for aggregate effects from mortality, injury, masking, habitat effects, energetic costs, stress, hearing loss, and behavioral harassment from the Navy's activities in reaching the negligible impact determinations. Significant additional discussion has been added to the Analysis and Negligible Impact Determination section of the final rule to better explain the potential for aggregate or cumulative effects on individuals as well as how these effects on individuals relate to potential effects on annual rates of recruitment and survival for each species or stock.

In addition, NMFS fully considers the potential for aggregate effects from all Navy activities. We also consider UMEs and previous environmental impacts, where appropriate, to inform the baseline levels of both individual health and susceptibility to additional stressors, as well as stock status. Further, the species and stock-specific assessments in the Analysis and Negligible Impact Determination section (which have been updated and expanded) pull together and address the combined mortality, injury, behavioral harassment, and other effects of the aggregate HSTT activities (and in consideration of applicable mitigation) as well as other information that supports our determinations that the Navy activities will not adversely affect any species or stocks via impacts on rates of recruitment or survival. We refer the reader to the Analysis and Negligible Impact Determination section for this analysis.

Widespread, extensive monitoring since 2006 on Navy ranges that have been used for training and testing for decades has demonstrated no evidence of population-level impacts. Based on the best available research from NMFS and Navy-funded marine mammal studies, there is no evidence that “population-level harm” to marine mammals, including beaked whales, is occurring in the HSTT Study Area. The presence of numerous small, resident populations of cetaceans, documented high abundances, and populations trending to increase for many marine mammals species in the area suggests there are not likely population-level consequences resulting from decades of ongoing Navy training and testing activities. Through the process described in the rule and the LOAs, the Navy will work with NMFS to assure that the aggregate or cumulative impacts remain at the negligible impact level.

Regarding the consideration of stress responses, NMFS does not assume that the impacts are insignificant. There is currently neither adequate data nor mechanism by which the impacts of stress from acoustic exposure can be reliably and independently quantified. However, stress effects that result from noise exposure likely often occur concurrently with behavioral harassment and many are likely captured and considered in the quantification of other takes by harassment that occur when individuals come within a certain distance of a sound source (behavioral harassment, PTS, and TTS).

Comment 83: Some Commenters asserted that in reaching our MMPA negligible impact finding, NMFS did not adequately consider the cumulative impacts of the Navy's activities when combined with the effects of other non-Navy activities.

Response: Both the statute and the agency's implementing regulations call for analysis of the effects of the applicant's activities on the affected species and stocks, not analysis of other unrelated activities and their impacts on the species and stocks. That does not mean, however, that effects on the species and stocks caused by other non-Navy activities are ignored. The preamble for NMFS' implementing regulations under section 101(a)(5) (54 FR 40338; September 29, 1989) explains in response to comments that the impacts from other past and ongoing anthropogenic activities are to be incorporated into the negligible impact analysis via their impacts on the environmental baseline. Consistent with that direction, NMFS has factored into its negligible impact analyses the impacts of other past and ongoing anthropogenic activities via their impacts on the baseline (e.g., as reflected in the density/distribution and status of the species, population size and growth rate, and other relevant stressors (such as incidental mortality in commercial fisheries or UMEs)). See the Analysis and Negligible Impact Determination section of this rule.

Our 1989 final rule for the MMPA implementing regulations also addressed public comments regarding cumulative effects from future, unrelated activities. There we stated that such effects are not considered in making findings under section 101(a)(5) concerning negligible impact. We indicated that NMFS would consider cumulative effects that are reasonably foreseeable when preparing a NEPA analysis and also that reasonably foreseeable cumulative effects would be considered under section 7 of the ESA for ESA-listed species.

Also, as described further in the Analysis and Negligible Impact Determination section of the final rule, NMFS evaluated the impacts of HSTT authorized mortality on the affected stocks in consideration of other anticipated human-caused mortality, including the mortality predicted in the SARs for other activities along with other NMFS-permitted mortality (i.e., authorized as part of the Southwest Fisheries Science Center rule), using multiple factors, including PBR. As described in more detail in the Analysis and Negligible Impact Determination section, PBR was designed to identify the maximum number of animals that may be removed from a stock (not including natural mortalities) while allowing that stock to reach or maintain its OSP and is also helpful in informing whether mortality will adversely affect annual rates of recruitment or survival in the context of a section 101(a)(5)(A).

NEPA

Comment 84: Commenters commented that NMFS cannot rely on Start Printed Page 66914the Navy's HSTT FEIS/OEIS to fulfill its obligations under NEPA because the purpose and need is too narrow and does not support NMFS' MMPA action, and therefore the HSTT FEIS/OEIS does not explore a reasonable range of alternatives.

Response: The proposed action at issue is the Navy's proposal to conduct testing and training activities in the HSTT Study Area. NMFS is a cooperating agency for that proposed action, as it has jurisdiction by law and special expertise over marine resources impacted by the proposed action, including marine mammals and federally-listed threatened and endangered species. Consistent with the regulations published by the Council on Environmental Quality (CEQ), it is common and sound NEPA practice for NOAA to adopt a lead agency's NEPA analysis when, after independent review, NOAA determines the document to be sufficient in accordance with 40 CFR 1506.3. Specifically here, NOAA must be satisfied that the Navy's EIS adequately addresses the impacts of issuing the MMPA incidental take authorization and that NOAA's comments and concerns have been adequately addressed. There is no requirement in CEQ regulations that NMFS, as a cooperating agency, issue a separate purpose and need statement in order to ensure adequacy and sufficiency for adoption. Nevertheless, the Navy, in coordination with NMFS, has clarified the statement of purpose and need in the HSTT FEIS/OEIS to more explicitly acknowledge NMFS' action of issuing an MMPA incidental take authorization. NMFS also clarified how its regulatory role under the MMPA related to Navy's activities. NMFS' early participation in the NEPA process and role in shaping and informing analyses using its special expertise ensured that the analysis in the HSTT FEIS/OEIS is sufficient for purposes of NMFS' own NEPA obligations related to its issuance of incidental take authorization under the MMPA.

Regarding the alternatives, NMFS' early involvement in development of the HSTT EIS/OEIS and role in evaluating the effects of incidental take under the MMPA ensured that the HSTT DEIS/OEIS would include adequate analysis of a reasonable range of alternatives. The HSTT FEIS/OEIS includes a No Action Alternative specifically to address what could happen if NMFS did not issue an MMPA authorization. The other two Alternatives address two action options that the Navy could potentially pursue while also meeting their mandated Title 10 training and testing responsibilities. More importantly, these alternatives fully analyze a comprehensive variety of mitigation measures. This mitigation analysis supported NMFS' evaluation of our options in potentially issuing an MMPA authorization, which, if the authorization may be issued, primarily revolves around the appropriate mitigation to prescribe. This approach to evaluating a reasonable range of alternatives is consistent with NMFS policy and practice for issuing MMPA incidental take authorizations. NOAA has independently reviewed and evaluated the EIS, including the purpose and need statement and range of alternatives, and determined that the HSTT FEIS/OEIS fully satisfies NMFS' NEPA obligations related to its decision to issue the MMPA final rule and associated LOAs, and we have adopted it.

Endangered Species Act

Comment 85: A commenter commented that under the ESA NMFS has the discretion to impose terms, conditions, and mitigation on any authorization. They believe the proposed action clearly affects listed whales, sea turtles, and Hawaiian monk seals, triggering the duty to consult. The commenter urged NMFS to fully comply with the ESA and implement robust reasonable and prudent alternatives and conservation measures to avoid harm to endangered species and their habitats.

Response: NMFS has fully complied with the ESA. The agency consulted pursuant to section 7 of the ESA and NMFS' ESA Interagency Cooperation Division provided a biological opinion concluded that NMFS' action of issuing MMPA incidental take regulations for the Navy HSTT activities would not jeopardize the continued existence of any threatened or endangered species and nor would it adversely modify any designated critical habitat. The biological opinion may be viewed at: https://www.fisheries.noaa.gov/​national/​marine-mammal-protection/​incidental-take-authorizations-military-readiness-activities.

Description of Marine Mammals and Their Habitat in the Area of the Specified Activities

Marine mammal species and their associated stocks that have the potential to occur in the HSTT Study Area are presented in Table 13 along with an abundance estimate, an associated coefficient of variation value, and best/minimum abundance estimates. The Navy anticipates the take of 39 individual marine mammal species by Level A and B harassment incidental to training and testing activities from the use of sonar and other transducers, in-water detonations, air guns, and impact pile driving/vibratory extraction activities. In addition, the Navy requested authorization for ten serious injuries or mortalities combined of two marine mammal stocks from explosives, and three takes of large whales by serious injury or mortality from vessel strikes over the five-year period. Two marine mammal species, the Hawaiian monk seal and the Main Hawaiian Islands Insular false killer whale, have critical habitat designated under the ESA in the HSTT Study Area (described below).

The species considered but not carried forward for analysis are two American Samoa stocks of spinner dolphins—(1) the Kure and Midway stock and (2) the Pearl and Hermes stock. There is no potential for overlap with any stressors from Navy activities and therefore there would be no incidental takes, in which case, these stocks are not considered further.

We presented a detailed discussion of marine mammals and their occurrence in the planned action area, inclusive of ESA-designated critical habitat, BIAs, National Marine Sanctuaries, and unusual mortality events (UMEs) in our Federal Register notice of proposed rulemaking (83 FR 29872; June 26, 2018); please see that notice of proposed rulemaking or the Navy's application for more information. There have been no changes or new information on BIAs and National Marine Sanctuaries since publication of the proposed rule; therefore, they are not discussed further. Additional information on certain ESA-designated critical habitat and UMEs has become available and so both of these topics are discussed following Table 13.Start Printed Page 66915

Table 13—Marine Mammal Occurrence Within the HSTT Study Area

Common nameScientific nameStockStatusOccurrenceSeasonal absenceStock abundance (CV)/minimum population
MMPAESA
Blue whaleBalaenoptera musculusEastern North PacificStrategic, DepletedEndangeredSouthern California1,647 (0.07)/1,551
Central North PacificStrategic, DepletedEndangeredHawaiiSummer133 (1.09)/63
Bryde's whaleBalaenoptera brydei/edeniEastern Tropical PacificSouthern Californiaunknown
HawaiiHawaii1,751 (0.29)/1,378
Fin whaleBalaenoptera physalusCA/OR/WAStrategic, DepletedEndangeredSouthern California9,029 (0.12)/8,127
HawaiiStrategic, DepletedEndangeredHawaiiSummer154 (1.05)/75
Gray whaleEschrichtius robustusEastern North PacificSouthern California26,960 (0.05)/25,849
Western North PacificStrategic, DepletedEndangeredSouthern California175 (0.05)/167
Humpback whaleMegaptera novaeangliaeCA/OR/WAStrategic, DepletedThreatened/ Endangered 1Southern California2,900 (0.03)/2,784
Central North PacificStrategicHawaiiSummer10,103 (0.30)/7,891
Minke whaleBalaenoptera acutorostrataCA/OR/WASouthern California636 (0.72)/369
HawaiiHawaiiSummerunknown
Sei whaleBalaenoptera borealisEastern North PacificStrategic, DepletedEndangeredSouthern California519 (0.4)/374
HawaiiStrategic, DepletedEndangeredHawaiiSummer391 (0.90)/204
Sperm whalePhyseter macrocephalusCA/OR/WAStrategic, DepletedEndangeredSouthern California1,997 (0.57)/1,270
HawaiiStrategic, DepletedEndangeredHawaii4,559 (0.33)/3,478
Pygmy sperm whaleKogia brevicepsCA/OR/WASouthern CaliforniaWinter and Fall4,111 (1.12)/1,924
HawaiiHawaiiunknown
Dwarf sperm whaleKogia simaCA/OR/WASouthern Californiaunknown
HawaiiHawaiiunknown
Baird's beaked whaleBerardius bairdiiCA/OR/WASouthern California2,697 (0.6)/1,633
Blainville's beaked whaleMesoplodon densirostrisHawaiiHawaii2,105 (1.13)/980
Cuvier's beaked whaleZiphius cavirostrisCA/OR/WASouthern California3,274 (0.67)/2,059
HawaiiHawaii723 0.69/428
Longman's beaked whaleIndopacetus pacificusHawaiiHawaii7,619 (0.66)/4,592
Mesoplodon beaked whalesMesoplodon sppCA/OR/WASouthern California3,044 (0.54)/1,967
Common Bottlenose dolphinTursiops truncatusCalifornia CoastalSouthern California453 (0.06)/346
CA/OR/WA OffshoreSouthern California1,924 (0.54)/1,255
Hawaii PelagicHawaii21,815 (0.57)/13.957
Kauai and NiihauHawaiiNA NA/97
OahuHawaiiNA
4-IslandsHawaiiNA
Hawaii IslandHawaiiNA NA/91
False killer whalePseudorca crassidensMain Hawaiian Islands InsularStrategic, DepletedEndangeredHawaii167 (0.14)/149
Start Printed Page 66916
Hawaii PelagicHawaii1,540 (0.66)/928
Northwestern Hawaiian IslandsHawaii617 (1.11)/290
Fraser's dolphinLagenodelphis hoseiHawaiiHawaii51,491 (0.66)/31,034
Killer whaleOrcinus orcaEastern North Pacific OffshoreSouthern California300 (0.1)/276
Eastern North Pacific Transient/West Coast Transient 2Southern California243 unknown/243
HawaiiHawaii146 (0.96)/74
Long-beaked common dolphinDelphinus capensisCaliforniaSouthern California101,305 (0.49)/68,432
Melon-headed whalePeponocephala electraHawaiian IslandsHawaii8,666 (1.00)/4,299
Kohala ResidentHawaii447 (0.12)/404
Northern right whale dolphinLissodelphis borealisCA/OR/WASouthern California26,556 (0.44)/18,608
Pacific white-sided dolphinLagenorhynchus obliquidensCA/OR/WASouthern California26,814 (0.28)/21,195
Pantropical spotted dolphinStenella attenuataOahuHawaiiunknown
4-IslandsHawaiiunknown
Hawaii IslandHawaiiunknown
Hawaii PelagicHawaii55,795 (0.40)/40,338
Pygmy killer whaleFeresa attenuataTropicalSouthern CaliforniaWinter & Springunknown
HawaiiHawaii10,640 (0.53)/6,998
Risso's dolphinsGrampus griseusCA/OR/WASouthern California6,336 (0.32)/4,817
HawaiiHawaii11,613 (0.43)/8,210
Rough-toothed dolphinSteno bredanensisNSD 3Southern Californiaunknown
HawaiiHawaii72,528 (0.39)/52,833
Short-beaked common dolphinDelphinus delphisCA/OR/WASouthern California969,861 (0.17)/839,325
Short-finned pilot whaleGlobicephala macrorhynchusCA/OR/WASouthern California836 (0.79)/466
HawaiiHawaii19,503 (0.49)/13,197
Spinner dolphinStenella longirostrisHawaii PelagicHawaiiunknown
Hawaii IslandHawaii665 (0.09)/617
Oahu and 4-IslandsHawaiiNA
Kauai and NiihauHawaiiNA
Kure and MidwayHawaiiunknown
Pearl and HermesHawaiiunknown
Striped dolphinStenella coeruleoalbaCA/OR/WASouthern California29,211 (0.20)/24,782
Start Printed Page 66917
HawaiiHawaii61,021 (0.38)/44,922
Dall's porpoisePhocoenoides dalliCA/OR/WASouthern California25,750 (0.45)/17,954
Harbor sealPhoca vitulinaCaliforniaSouthern California30,968 NA/27,348
Hawaiian monk sealNeomonachus schauinslandiHawaiiStrategic, DepletedEndangeredHawaii1,415 (0.03)/1,384
Northern elephant sealMirounga angustirostrisCaliforniaSouthern California179,000 NA/81,368
California sea lionZalophus californianusU.S. StockSouthern California257,606 NA/233,515
Guadalupe fur sealArctocephalus townsendiMexico to CaliforniaStrategic, DepletedThreatenedSouthern California20,000 NA/15,830
Northern fur sealCallorhinus ursinusCaliforniaSouthern California14,050 NA/7,524
1 The two humpback whale Distinct Population Segments making up the California, Oregon, and Washington stock present in Southern California are the Mexico Distinct Population Segment, listed under the ESA as Threatened, and the Central America Distinct Population Segment, which is listed under the ESA as Endangered.
2 This stock is mentioned briefly in the Pacific Stock Assessment Report (Carretta et al., 2017) and referred to as the “Eastern North Pacific Transient” stock; however, the Alaska Stock Assessment Report contains assessments of all transient killer whale stocks in the Pacific and the Alaska Stock Assessment Report refers to this same stock as the “West Coast Transient” stock (Muto et al., 2017).
3 NSD—No stock designation. Rough-toothed dolphin has a range known to include the waters off Southern California, but there is no recognized stock or data available for the U.S. West Coast.

The proposed rule (83 FR 29909, June 26, 2018) includes a description of ESA designated critical habitat, BIAs, National Marine Sanctuaries, and unusual mortality events that are applicable in the HSTT Study area and that material remains applicable and is not repeated here. However, we do include information where anything has changed. In this case, since the proposed rule was published, ESA designated critical habitat for main Hawaiian Islands insular false killer whales was finalized and new information regarding the California sea lion UME became available.

Critical habitat for the ESA-listed Main Hawaiian Islands insular false killer whale DPS was finalized in July 2018 (83 FR 35062; July 24, 2018) designating waters from the 45 m depth contour to the 3,200 m depth contour around the main Hawaiian Islands from Niihau east to Hawaii. This designation does not include most bays, harbors, or coastal in-water structures. NMFS excluded 14 areas (one area, with two sites, for the Bureau of Ocean Energy Management and 13 areas requested by the Navy) from the critical habitat designation because it was determined that the benefits of exclusion outweighed the benefits of inclusion, and exclusion would not result in extinction of the species. In addition, two areas, the Ewa Training Minefield and the Naval Defensive Sea Area, were ineligible for designation because they are managed under the Joint Base Pearl Harbor-Hickam Integrated Natural Resources Management Plan that was found to benefit main Hawaiian Islands insular false killer whales. The total area designated was approximately 45,504 km2 (17,564 mi2) of marine habitat and the designation stresses the importance of protecting: adequate space for movement and use; prey species of sufficient quantity, quality, and availability to support growth and reproduction; waters free of harmful types and amounts of pollutants; and sound levels that would not significantly impair false killer whale use or occupancy.

Regarding the California sea lion UME, although this UME has not been closed, NMFS staff recently confirmed that the mortality of pups and yearlings returned to normal in 2017 and 2018 and they plan to present it to the Working Group to discuss closure by the end of 2018 (Deb Fauquier, pers. comm.). Please refer to the proposed rule (83 FR 29872; June 26, 2018) and NMFS' website at https://www.fisheries.noaa.gov/​national/​marine-life-distress/​2013-2017-california-sea-lion-unusual-mortality-event-california for more information on this UME.

Potential Effects of Specified Activities on Marine Mammals and Their Habitat

We provided a summary and discussion of the potential effects of the specified activity on marine mammals and their habitat in our Federal Register notice of proposed rulemaking (83 FR 29872; June 26, 2018). In the Potential Effects of Specified Activities on Marine Mammals and Their Habitat section of the proposed rule, NMFS provided a description of the ways marine mammals may be affected by these activities in the form of serious injury or mortality, physical trauma, sensory impairment (permanent and temporary threshold shift and acoustic masking), physiological responses (particular stress responses), behavioral disturbance, or habitat effects. Therefore, we do not reprint the information here but refer the reader to that document. For additional summary and discussion of recent scientific studies not included in the proposed rulemaking, we direct the reader to the HSTT FEIS/OEIS (Chapter 3, Section 3.7 Marine Mammals, http://www.hstteis.com/​), which NMFS participated in the development of via our cooperating agency status and adopted to meet our NEPA requirements. We highlight several studies below, but direct the reader to the HSTT FEIS/OEIS for a full compilation. As noted above, NMFS has reviewed and accepted the Navy's compilation and interpretation of the best available science contained in the HSTT FEIS/OEIS. More specifically, we have independently reviewed the more recent studies that were not included in NMFS' proposed rule, have concluded that the Navy's descriptions and interpretations of those studies in the Start Printed Page 66918FEIS/OEIS are accurate, and have taken those studies into consideration in our analyses that inform our negligible impact determinations. Importantly, we note that none of the newer information highlighted here or in the HSTT FEIS/OEIS affects our analysis in a manner that changes our determinations under the MMPA from the proposed rule.

The Acoustic Technical Guidance (NMFS, 2018), which was used in the assessment of effects for this action, compiled, interpreted, and synthesized the best available scientific information for noise-induced hearing effects for marine mammals to derive updated thresholds for assessing the impacts of noise on marine mammal hearing. New data on killer whale hearing (Branstetter et al., 2017), harbor porpoise hearing (Kastelein et al., 2017a), harbor porpoise threshold shift (TS) in response to airguns (Kastelein et al., 2017b) and mid-frequency sonar (Kastelein et al., 2017c), and harbor seal TS in response to pile-driving sounds (Kastelein et al., 2018) are consistent with data included and thresholds presented in the Acoustic Technical Guidance.

Recent studies with captive odontocete species (bottlenose dolphin, harbor porpoise, beluga, and false killer whale) have observed increases in hearing threshold levels when individuals received a warning sound prior to exposure to a relatively loud sound (Finneran, 2018; Nachtigall and Supin, 2013, 2015; Nachtigall et al., 2016a,b,c; Nachtigall, et al., 2018). These studies suggest that captive animals have a mechanism to reduce hearing sensitivity prior to impending loud sounds. Hearing change was observed to be frequency dependent and Finneran (2018) suggests hearing attenuation occurs within the cochlea or auditory nerve. Based on these observations on captive odontocetes, the authors suggest that wild animals may have a mechanism to self-mitigate the impacts of noise exposure by dampening their hearing during prolonged exposures of loud sound, or if conditioned to anticipate intense sounds (Finneran, 2018, Nachtigall et al., 2018).

Recent reviews have synthesized data from experimental studies examining marine mammal behavioral response to anthropogenic sound, and have documented large variances in individual behavioral responses to anthropogenic sound both within and among marine mammal species. These reviews highlight the importance of the exposure context (e.g., behavioral state, presence of other animals and social relationships, prey abundance, distance to source, presence of vessels, environmental parameters, etc.) in determining or predicting a behavioral response. As described in the proposed rule, in a review of experimental field studies to measure behavioral responses of cetaceans to sonar, Southall et al. (2016) observed that some individuals of different species display clear yet varied responses (some of which have negative implications), while others appear to tolerate high levels. Results from the studies they investigated demonstrate that responses are highly variable and may not be fully predictable with simple acoustic exposure metrics (e.g., received sound level). Rather, differences among species and individuals along with contextual aspects of exposure (e.g., behavioral state) appear to affect response probability (Southall et al., 2016). Dunlop et al. (2018) combined data from the BRAHSS (Behavioural Response of Australian Humpback whales to Seismic Surveys) studies designed to examine the behavioral responses of migrating humpback whales to various seismic array sources to develop a dose-response model. The model accounted for other variables such as presence of the vessel, array towpath relative to the migration, and social and environmental parameters. Authors observed that whales were more likely to avoid the airgun or array (defined by increasing their distance from the source) when they were exposed to sounds greater than 130 dB re 1 μPa2·s and they were within 4 km of the source (Dunlop et al., 2018). At sound exposure levels of 150-155 dB re 1 μPa2·s and less than 2.5 km from the source the model predicted a 50 percent probability of response (Dunlop et al., 2018). However, it was not possible to estimate the maximum response threshold as at the highest received levels of 160-170 dB re 1 μPa2·s, a small number of whales moving rapidly and close to the source did not exhibit an avoidance response as defined by the study (Dunlop et al., 2018).

Estimated Take of Marine Mammals

This section indicates the number of takes that NMFS is authorizing, which are based on the amount of take that NMFS anticipates could occur or is likely to occur, depending on the type of take and the methods used to estimate it, as described in detail below. NMFS coordinated closely with the Navy in the development of their incidental take application, and with one limited exception, agrees that the methods the Navy put forth in their application to estimate take (including the model, thresholds, and density estimates), and the resulting numbers are based on the best available science and appropriate for authorization. As noted elsewhere, additional discussion and subsequent analysis led both NMFS and the Navy, in coordination, to conclude that different take estimates for serious injury or mortality from vessel strikes were appropriate, and where those numbers differ from the Navy's application or our proposed rule, NMFS has explicitly described our rationale and indicated what we consider an appropriate number of takes.

Takes are predominantly in the form of harassment, but a small number of serious injuries or mortalities are also authorized. For military readiness activities, the MMPA defines “harassment” as: (i) Any act that injures or has the significant potential to injure a marine mammal or marine mammal stock in the wild (Level A harassment); or (ii) Any act that disturbs or is likely to disturb a marine mammal or marine mammal stock in the wild by causing disruption of natural behavioral patterns, including, but not limited to, migration, surfacing, nursing, breeding, feeding, or sheltering, to a point where such behavioral patterns are abandoned or significantly altered (Level B harassment).

Authorized takes would primarily be in the form of Level B harassment, as use of the acoustic and explosive sources (i.e., sonar, air guns, pile driving, explosives) is more likely to result in the disruption of natural behavioral patterns to a point where they are abandoned or significantly altered (as defined specifically in the paragraph above, but referred to generally as behavioral disruption) or TTS for marine mammals than other forms of take. There is also the potential for Level A harassment, however, in the form of auditory injury and/or tissue damage (the latter from explosives only) to result from exposure to the sound sources utilized in training and testing activities. Lastly, a limited number of serious injuries or mortalities could occur for California sea lion and short-beaked common dolphin (10 mortalities total between the two species over a five year period) from explosives, and no more than three serious injuries or mortalities total (over the five-year period) of large whales through vessel collisions. Although we analyze the impacts of these potential serious injuries or mortalities that are authorized, the required mitigation and monitoring measures are expected to minimize the likelihood that ship strike or these high level explosive exposures (and the associated serious injury or mortality) actually occur.Start Printed Page 66919

Generally speaking, for acoustic impacts we estimate the amount and type of harassment by considering: (1) Acoustic thresholds above which NMFS believes the best available science indicates marine mammals will be taken by Level B harassment (in this case, as defined in the military readiness definition of Level B harassment included above) or incur some degree of temporary or permanent hearing impairment; (2) the area or volume of water that will be ensonified above these levels in a day or event; (3) the density or occurrence of marine mammals within these ensonified areas; and (4) the number of days of activities or events. Below, we describe these components in more detail and present the take estimate.

Acoustic Thresholds

Using the best available science, NMFS, in coordination with the Navy, has established acoustic thresholds that identify the most appropriate received level of underwater sound above which marine mammals exposed to these sound sources could be reasonably expected to experience a disruption in behavior patterns to a point where they are abandoned or significantly altered, or to incur TTS (equated to Level B harassment) or PTS of some degree (equated to Level A harassment). Thresholds have also been developed to identify the pressure levels above which animals may incur non-auditory injury from exposure to pressure waves from explosive detonation.

Despite the quickly evolving science, there are still challenges in quantifying expected behavioral responses that qualify as Level B harassment, especially where the goal is to use one or two predictable indicators (e.g., received level and distance) to predict responses that are also driven by additional factors that cannot be easily incorporated into the thresholds (e.g., context). So, while the new Level B behavioral harassment thresholds have been refined here to better consider the best available science (e.g., incorporating both received level and distance), they also still, accordingly, have some built-in conservative factors to address the challenge noted. For example, while duration of observed responses in the data are now considered in the thresholds, some of the responses that are informing take thresholds are of a very short duration, such that it is possible some of these responses might not always rise to the level of disrupting behavior patterns to a point where they are abandoned or significantly altered. We describe the application of this Level B behavioral harassment threshold as identifying the maximum number of instances in which marine mammals could be reasonably expected to experience a disruption in behavior patterns to a point where they are abandoned or significantly altered. In summary, we believe these Level B behavioral harassment thresholds are the most appropriate method for predicting Level B behavioral harassment given the best available science and the associated uncertainty. Hearing Impairment (TTS/PTS and Tissues Damage and Mortality)

Non-Impulsive and Impulsive

NMFS' Acoustic Technical Guidance (NMFS, 2018) identifies dual criteria to assess auditory injury (Level A harassment) to five different marine mammal groups (based on hearing sensitivity) as a result of exposure to noise from two different types of sources (impulsive or non-impulsive). The Acoustic Technical Guidance also identifies criteria to predict TTS, which is not considered injury and falls into the Level B harassment category. The Navy's planned activity includes the use of non-impulsive (sonar, vibratory pile driving/removal) and impulsive (explosives, airguns, impact pile driving) sources.

These thresholds (Tables 14-15) were developed by compiling and synthesizing the best available science and soliciting input multiple times from both the public and peer reviewers. The references, analysis, and methodology used in the development of the thresholds are described in Acoustic Technical Guidance, which may be accessed at: https://www.fisheries.noaa.gov/​national/​marine-mammal-protection/​marine-mammal-acoustic-technical-guidance.

Table 14—Acoustic Thresholds Identifying the Onset of TTS and PTS for Non-Impulsive Sound Sources by Functional Hearing Groups

Functional hearing groupNon-impulsive
TTS threshold SEL (weighted)PTS threshold SEL (weighted)
Low-Frequency Cetaceans179199
Mid-Frequency Cetaceans178198
High-Frequency Cetaceans153173
Phocid Pinnipeds (Underwater)181201
Otarid Pinnipeds (Underwater)199219
Note: SEL thresholds in dB re 1 μPa2 s.

Based on the best available science, the Navy (in coordination with NMFS) used the acoustic and pressure thresholds indicated in Table 15 to predict the onset of TTS, PTS, tissue damage, and mortality for explosives (impulsive) and other impulsive sound sources.

Table 15—Onset of TTS, PTS, Tissue Damage, and Mortality Thresholds for Marine Mammals for Explosives and Other Impulsive Sources

Functional hearing groupSpeciesOnset TTSOnset PTSMean onset slight GI tract injuryMean onset slight lung injuryMean onset mortality
Low-frequency cetaceansAll mysticetes168 dB SEL (weighted) or 213 dB Peak SPL183 dB SEL (weighted) or 219 dB Peak SPL237 dB Peak SPLEquation 1Equation 2.
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Mid-frequency cetaceansMost delphinids, medium and large toothed whales170 dB SEL (weighted) or 224 dB Peak SPL185 dB SEL (weighted) or 230 dB Peak SPL237 dB Peak SPL
High-frequency cetaceansPorpoises and Kogia spp140 dB SEL (weighted) or 196 dB Peak SPL155 dB SEL (weighted) or 202 dB Peak SPL237 dB Peak SPL
PhocidaeHarbor seal, Hawaiian monk seal, Northern elephant seal170 dB SEL (weighted) or 212 dB Peak SPL185 dB SEL (weighted) or 218 dB Peak SPL237 dB Peak SPL
OtariidaeCalifornia sea lion, Guadalupe fur seal, Northern fur seal188 dB SEL (weighted) or 226 dB Peak SPL203 dB SEL (weighted) or 232 dB Peak SPL237 dB Peak SPL
Notes:
Equation 1: 47.5M1/3 (1+[DRm/10.1])1/6 Pa-sec.
Equation 2: 103M1/3 (1+[DRm/10.1])1/6 Pa-sec.
M = mass of the animals in kg.
DRm = depth of the receiver (animal) in meters.
SPL = sound pressure level.

Impulsive—Air Guns and Impact Pile Driving

Impact pile driving produces impulsive noise; therefore, the criteria used to assess the onset of TTS and PTS are identical to those used for air guns, as well as explosives (see Table 15 above) (see Hearing Loss from Air Guns in Chapter 6 Section 6.4.3.1, Methods for Analyzing Impacts from air guns in the Navy's rulemaking/LOA application). Refer to the Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III) report (U.S. Department of the Navy, 2017c) for detailed information on how the criteria and thresholds were derived.

Non-Impulsive—Sonar and Vibratory Pile Driving/Removal

Vibratory pile removal (that will be used during the ELCAS) creates continuous non-impulsive noise at low source levels for a short duration. Therefore, the criteria used to assess the onset of TTS and PTS due to exposure to sonars (non-impulsive, see Table 14 above) are also used to assess auditory impacts to marine mammals from vibratory pile driving (see Hearing Loss from Sonar and Other Transducers in Chapter 6, Section 6.4.2.1, Methods for Analyzing Impacts from Sonars and Other Transducers in the Navy's rulemaking/LOA application). Refer to the Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III) report (U.S. Department of the Navy, 2017c) for detailed information on how the criteria and thresholds were derived. Non-auditory injury (i.e., other than PTS) and mortality from sonar and other transducers is so unlikely as to be discountable under normal conditions for the reasons explained in the proposed rule under Potential Effects of Specified Activities on Marine Mammals and Their Habitat section—Acoustically Mediated Bubble Growth and other Pressure-related Injury and is therefore not considered further in this analysis.

Behavioral Harassment

Though significantly driven by received level, the onset of Level B harassment by behavioral disturbance from anthropogenic noise exposure is also informed to varying degrees by other factors related to the source (e.g., frequency, predictability, duty cycle), the environment (e.g., bathymetry), and the receiving animals (hearing, motivation, experience, demography, behavioral context) and can be difficult to predict (Ellison et al., 2011; Southall et al., 2007). Based on what the available science indicates and the practical need to use thresholds based on a factor, or factors, that are both predictable and measurable for most activities, NMFS uses generalized acoustic thresholds based primarily on received level (and distance in some cases) to estimate the onset of Level B behavioral harassment.

Air Guns and Pile Driving

For air guns and pile driving, NMFS predicts that marine mammals are likely to be taken by Level B behavioral harassment when exposed to underwater anthropogenic noise above received levels of 120 dB re 1 μPa (rms) for continuous (e.g., vibratory pile-driving, drilling) and above 160 dB re 1 μPa (rms) for non-explosive impulsive (e.g., seismic air guns) or intermittent (e.g., scientific sonar) sources. To estimate Level B behavioral harassment from air guns, the existing NMFS Level B harassment threshold of 160 dB re 1 µPa (rms) is used. The rms calculation for air guns is based on the duration defined by 90 percent of the cumulative energy in the impulse.

The existing NMFS Level B harassment thresholds were also applied to estimate Level B behavioral harassment from impact and vibratory pile driving (Table 16).

Table 16—Pile Driving Level B Harassment Thresholds Used in This Analysis To Predict Behavioral Responses From Marine Mammals

Pile driving criteria (SPL, dB re 1 μPa)Level B harassment threshold
Underwater vibratoryUnderwater impact
120 dB rms160 dB rms.
Notes: Root mean square calculation for impact pile driving is based on the duration defined by 90 percent of the cumulative energy in the impulse. Root mean square for vibratory pile driving is calculated based on a representative time series long enough to capture the variation in levels, usually on the order of a few seconds. dB: decibel; dB re 1 µPa: decibel referenced to 1 micropascal; rms: root mean square.

Sonar

As noted above, the Navy coordinated with NMFS to propose Level B behavioral harassment thresholds specific to their military readiness Start Printed Page 66921activities utilizing active sonar. Behavioral response criteria are used to estimate the number of animals that may exhibit a behavioral response to sonar and other transducers. The way the criteria were derived is discussed in detail in the Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III) report (U.S. Department of the Navy, 2017c). Developing the new Level B harassment behavioral criteria involved multiple steps. All peer-reviewed published behavioral response studies conducted both in the field and on captive animals were examined in order to understand the breadth of behavioral responses of marine mammals to sonar and other transducers. NMFS has carefully reviewed the Navy's Level B behavioral thresholds and establishment of cutoff distances for the species, and agrees that it is the best available science and is the appropriate method to use at this time for determining impacts to marine mammals from sonar and other transducers and for calculating take and to support the determinations made in the final rule.

As noted above, marine mammal responses to sound (some of which are considered disturbances that rise to the level of a take) are highly variable and context specific, i.e., they are affected by differences in acoustic conditions; differences between species and populations; differences in gender, age, reproductive status, or social behavior; or other prior experience of the individuals. This means that there is support for considering alternative approaches for estimating Level B behavioral harassment. Although the statutory definition of Level B harassment for military readiness activities means that a natural behavior pattern of a marine mammal is significantly altered or abandoned, the current state of science for determining those thresholds is somewhat unsettled.

In its analysis of impacts associated with sonar acoustic sources (which was coordinated with NMFS), the Navy used an updated conservative approach that likely overestimates the number of takes by Level B harassment due to behavioral disturbance and response. Many of the behavioral responses identified using the Navy's quantitative analysis are most likely to be of moderate severity as described in the Southall et al. (2007) behavioral response severity scale. These “moderate” severity responses were considered significant if they were sustained for the duration of the exposure or longer. Within the Navy's quantitative analysis, many reactions are predicted from exposure to sound that may exceed an animal's Level B behavioral harassment threshold for only a single exposure (a few seconds) to several minutes, and it is likely that some of the resulting estimated behavioral responses that are counted as Level B harassment would not constitute “significantly altering or abandoning natural behavioral patterns.” The Navy and NMFS have used the best available science to address the challenging differentiation between significant and non-significant behavioral reactions (i.e., whether the behavior has been abandoned or significantly altered such that it qualifies as harassment), but have erred on the cautious side where uncertainty exists (e.g., counting these lower duration reactions as take), which likely results in some degree of overestimation of Level B behavioral harassment. We consider application of this Level B behavioral harassment threshold, therefore, as identifying the maximum number of instances in which marine mammals could be reasonably expected to experience a disruption in behavior patterns to a point where they are abandoned or significantly altered (i.e., Level B harassment). Because this is the most appropriate method for estimating Level B harassment given the best available science and uncertainty on the topic, it is these numbers of Level B harassment by behavioral disturbance that are analyzed in the Analysis and Negligible Impact Determination section and are being authorized.

In the Navy's acoustic impact analyses during Phase II, the likelihood of Level B behavioral harassment in response to sonar and other transducers was based on a probabilistic function (termed a behavioral response function—BRF), that related the likelihood (i.e., probability) of a behavioral response (at the level of a Level B harassment) to the received SPL. The BRF was used to estimate the percentage of an exposed population that is likely to exhibit Level B harassment due to altered behaviors or behavioral disturbance at a given received SPL. This BRF relied on the assumption that sound poses a negligible risk to marine mammals if they are exposed to SPL below a certain “basement” value. Above the basement exposure SPL, the probability of a response increased with increasing SPL. Two BRFs were used in Navy acoustic impact analyses: BRF1 for mysticetes and BRF2 for other species. BRFs were not used for beaked whales during Phase II analyses. Instead, a step function at an SPL of 140 dB re 1 μPa was used for beaked whales as the threshold to predict Level B harassment by behavioral disturbance. Of note, a separate step function at an SPL of 120 dB re 1 μPa was used for harbor porpoises in the 2013-2018 rule, but there are no harbor porpoises in the HSTT Study Area (and Dall's porpoises do not have the same behavioral sensitivities), so harbor porpoises are not discussed further.

Developing the new Level B behavioral harassment criteria for Phase III involved multiple steps: All available behavioral response studies conducted both in the field and on captive animals were examined to understand the breadth of behavioral responses of marine mammals to sonar and other transducers. Six behavioral response field studies with observations of 14 different marine mammal species reactions to sonar or sonar-like signals and 6 captive animal behavioral studies with observations of 8 different species reactions to sonar or sonar-like signals were used to provide a robust data set for the derivation of the Navy's Phase III marine mammal behavioral response criteria. All behavioral response research that has been published since the derivation of the Navy's Phase III criteria (c.a. December 2016) has been examined and is consistent with the current behavioral response functions. Marine mammal species were placed into behavioral criteria groups based on their known or suspected behavioral sensitivities to sound. In most cases these divisions were driven by taxonomic classifications (e.g., mysticetes, pinnipeds). The data from the behavioral studies were analyzed by looking for significant responses, or lack thereof, for each experimental session.

The Navy used cutoff distances beyond which the potential of significant behavioral responses (and therefore Level B harassment) is considered to be unlikely (see Table 17 below). This was determined by examining all available published field observations of behavioral reactions to sonar or sonar-like signals that included the distance between the sound source and the marine mammal. The longest distance, rounded up to the nearest 5-km increment, was chosen as the cutoff distance for each behavioral criteria group (i.e., odontocetes, mysticetes, pinnipeds, and beaked whales). For animals within the cutoff distance, a behavioral response function based on a received SPL as presented in Chapter 3, Section 3.1.0 of the Navy's rulemaking/LOA application was used to predict the probability of a potential significant behavioral response. For training and testing events that contain multiple platforms or tactical sonar sources that exceed 215 dB re 1 μPa @1 m, this cutoff Start Printed Page 66922distance is substantially increased (i.e., doubled) from values derived from the literature. The use of multiple platforms and intense sound sources are factors that probably increase responsiveness in marine mammals overall (however, we note that helicopter dipping sonars were considered in the intense sound source group, despite lower source levels, because of data indicating that marine mammals are sometimes more responsive to the less predictable employment of this source). There are currently few behavioral observations under these circumstances; therefore, the Navy conservatively predicted significant behavioral responses that would rise to Level B harassment at farther ranges as shown in Table 17, versus less intense events.

Table 17—Cutoff Distances for Moderate Source Level, Single Platform Training and Testing Events and for All Other Events With Multiple Platforms or Sonar With Source Levels at or Exceeding 215 dB re 1 μPa @1 m

Criteria groupModerate SlL/single platform cutoff distance (km)High SL/multi- platform cutoff distance (km)
Odontocetes1020
Pinnipeds510
Mysticetes1020
Beaked Whales2550
Note: dB re 1 μPa @1 m: Decibels referenced to 1 micropascal at 1 meter; km: Kilometer; SL: Source level.

The range to received sound levels in 6-dB steps from five representative sonar bins and the percentage of animals that may be taken by Level B harassment under each behavioral response function (or step function in the case of the harbor porpoise) are shown in Table 18 through Table 22. Cells are shaded if the mean range value for the specified received level exceeds the distance cutoff range for a particular hearing group and therefore are not included in the estimated take. See Chapter 6, Section 6.4.2.1.1 (Methods for Analyzing Impacts from Sonars and Other Transducers) of the Navy's rulemaking/LOA application for further details on the derivation and use of the behavioral response functions, thresholds, and the cutoff distances to identify takes by Level B harassment, which were coordinated with NMFS. Table 18 illustrates the maximum likely percentage of exposed individuals taken at the indicated received level and associated range (in which marine mammals would be reasonably expected to experience a disruption in behavior patterns to a point where they are abandoned or significantly altered) for LFAS. As noted previously, NMFS carefully reviewed, and contributed to, the Navy's proposed level B behavioral harassment thresholds and cutoff distances for the species, and agrees that these methods represent the best available science at this time for determining impacts to marine mammals from sonar and other transducers.

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Tables 19 through Table 21 identify the maximum likely percentage of exposed individuals taken at the indicated received level and associated range for MFAS.

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Table 22 identifies the maximum likely percentage of exposed individuals taken at the indicated received level and associated range for HFAS.

Explosives

Phase III explosive criteria for Level B behavioral harassment thresholds for marine mammals is the hearing groups' TTS threshold minus 5 dB (see Table 23 below and Table 15 for the TTS thresholds for explosives) for events that contain multiple impulses from explosives underwater. This was the same approach as taken in Phase II for explosive analysis. See the Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III) report (U.S. Department of the Navy, 2017c) for detailed information on how the criteria and thresholds were derived. NMFS continues to concur that this approach represents the best available science for determining impacts to marine mammals from explosives.Start Printed Page 66928

Table 23—Phase III Level B Behavioral Harassment Thresholds for Explosives for Marine Mammals

MediumFunctional hearing groupSEL (weighted)
UnderwaterLF163
UnderwaterMF165
UnderwaterHF135
UnderwaterPW165
UnderwaterOW183
Note: Weighted SEL thresholds in dB re 1 μPa2 s underwater. PW—pinnipeds underwater, OW—otariids underwater.

Navy's Acoustic Effects Model

Sonar and Other Transducers and Explosives

The Navy's Acoustic Effects Model calculates sound energy propagation from sonar and other transducers and explosives during naval activities and the sound received by animat dosimeters. Animat dosimeters are virtual representations of marine mammals distributed in the area around the modeled naval activity and each dosimeter records its individual sound “dose.” The model bases the distribution of animats over the HSTT Study Area on the density values in the Navy Marine Species Density Database and distributes animats in the water column proportional to the known time that species spend at varying depths.

The model accounts for environmental variability of sound propagation in both distance and depth when computing the received sound level received by the animats. The model conducts a statistical analysis based on multiple model runs to compute the estimated effects on animals. The number of animats that exceed the thresholds for effects is tallied to provide an estimate of the number of marine mammals that could be affected.

Assumptions in the Navy model intentionally err on the side of overestimation when there are unknowns. Naval activities are modeled as though they would occur regardless of proximity to marine mammals, meaning that no mitigation is considered (i.e., no power down or shut down modeled) and without any avoidance of the activity by the animal. The final step of the quantitative analysis of acoustic effects is to consider the implementation of mitigation and the possibility that marine mammals would avoid continued or repeated sound exposures. For more information on this process, see the discussion in the Take Requests subsection below. Many explosions from ordnance such as bombs and missiles actually occur upon impact with above-water targets. However, for this analysis, sources such as these were modeled as exploding underwater. This overestimates the amount of explosive and acoustic energy entering the water.

The model estimates the impacts caused by individual training and testing exercises. During any individual modeled event, impacts to individual animats are considered over 24-hour periods. The animats do not represent actual animals, but rather they represent a distribution of animals based on density and abundance data, which allows for a statistical analysis of the number of instances that marine mammals may be exposed to sound levels resulting in an effect. Therefore, the model estimates the number of instances in which an effect threshold was exceeded over the course of a year, but does not estimate the number of individual marine mammals that may be impacted over a year (i.e., some marine mammals could be impacted several times, while others would not experience any impact). A detailed explanation of the Navy's Acoustic Effects Model is provided in the technical report Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing report (U.S. Department of the Navy, 2018).

Air Guns and Pile Driving

The Navy's quantitative analysis estimates the sound and energy received by marine mammals distributed in the area around planned Navy activities involving air guns. See the technical report titled Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing report (U.S. Department of the Navy, 2018) for additional details.

Underwater noise effects from pile driving and vibratory pile extraction were modeled using actual measures of impact pile driving and vibratory removal during construction of an ELCAS (Illingworth and Rodkin, 2015, 2016). A conservative estimate of spreading loss of sound in shallow coastal waters (i.e., transmission loss = 16.5*Log10 (radius)) was applied based on spreading loss observed in actual measurements. Inputs used in the model are provided in Chapter 1, Section 1.4.1.3 (Pile Driving) of the Navy's rulemaking/LOA application, including source levels; the number of strikes required to drive a pile and the duration of vibratory removal per pile; the number of piles driven or removed per day; and the number of days of pile driving and removal.

Range to Effects

The following section provides range to effects for sonar and other active acoustic sources as well as explosives to specific acoustic thresholds determined using the Navy Acoustic Effects Model. Marine mammals exposed within these ranges for the shown duration are predicted to experience the associated effect. Range to effects is important information in not only predicting acoustic impacts, but also in verifying the accuracy of model results against real-world situations and determining adequate mitigation ranges to avoid higher level effects, especially physiological effects to marine mammals.

Sonar

The range to received sound levels in 6-dB steps from five representative sonar bins and the percentage of the total number of animals that may exhibit a significant behavioral response (and therefore Level B harassment) under each behavioral response function (or step function in the case of the harbor porpoise) are shown in Table 17 through Table 21 above, respectively. See Chapter 6, Section 6.4.2.1 (Methods for Analyzing Impacts from Sonars and Other Transducers) of the Navy's rulemaking/LOA application for additional details on the derivation and use of the behavioral response functions, thresholds, and the cutoff distances that are used to identify Level B behavioral harassment.

The ranges to PTS for five representative sonar systems for an exposure of 30 seconds is shown in Table 24 relative to the marine mammal's functional hearing group. This period (30 seconds) was chosen based on examining the maximum amount of time a marine mammal would realistically be exposed to levels that could cause the onset of PTS based on platform (e.g., ship) speed and a nominal animal swim speed of approximately 1.5 m per second. The ranges provided in the table include the average range to PTS, as well as the range from the minimum to the maximum distance at which PTS is possible for each hearing group.Start Printed Page 66929

Table 24—Range to Permanent Threshold Shift (Meters) for Five Representative Sonar Systems

Functional hearing groupApproximate range in meters for PTS from 30 seconds exposure
Sonar bin LFSonar bin MF1Sonar bin MF4Sonar bin MF5Sonar bin HF4
Low-frequency Cetacean0 (0-0)65 (65-65)14 (0-15)0 (0-0)0 (0-0)
Mid-frequency Cetacean0 (0-0)16 (16-16)3 (3-3)0 (0-0)1 (0-2)
High-frequency Cetacean0 (0-0)181 (180-190)30 (30-30)9 (8-10)30 (8-80)
Otariidae0 (0-0)6 (6-6)0 (0-0)0 (0-0)0 (0-0)
Phocidae0 (0-0)45 (45-45)11 (11-11)0 (0-0)0 (0-0)
1 PTS ranges extend from the sonar or other active acoustic sound source to the indicated distance. The average range to PTS is provided as well as the range from the estimated minimum to the maximum range to PTS in parenthesis.

The tables below illustrate the range to TTS for 1, 30, 60, and 120 seconds from five representative sonar systems (see Table 25 through Table 29).

Table 25—Ranges to Temporary Threshold Shift (Meters) for Sonar Bin LF5 Over a Representative Range of Environments Within the HSTT Study Area

Hearing groupApproximate TTS ranges (meters) 1
Sonar bin LF5M (low frequency sources <180 dB source level)
1 second30 seconds60 seconds120 seconds
Low-frequency Cetacean3 (0-4)3 (0-4)3 (0-4)3 (0-4)
Mid-frequency Cetacean0 (0-0)0 (0-0)0 (0-0)0 (0-0)
High-frequency Cetacean0 (0-0)0 (0-0)0 (0-0)0 (0-0)
Otariidae0 (0-0)0 (0-0)0 (0-0)0 (0-0)
Phocidae0 (0-0)0 (0-0)0 (0-0)0 (0-0)
1 Ranges to TTS represent the model predictions in different areas and seasons within the Study Area. The zone in which animals are expected to suffer TTS extend from onset-PTS to the distance indicated. The average range to TTS is provided as well as the range from the estimated minimum to the maximum range to TTS in parentheses.

Table 26—Ranges to Temporary Threshold Shift (Meters) for Sonar Bin MF1 Over a Representative Range of Environments within the HSTT Study Area

Hearing groupApproximate TTS ranges (meters) 1
Sonar bin MF1 (e.g., SQS-53 ASW hull-mounted sonar)
1 second30 seconds60 seconds120 seconds
Low-frequency Cetacean903 (850-1,025)903 (850-1,025)1,264 (1,025-2,275)1,839 (1,275-3,025)
Mid-frequency Cetacean210 (210-210)210 (210-210)302 (300-310)379 (370-390)
High-frequency Cetacean3,043 (1,525-4,775)3,043 (1,525-4,775)4,739 (2,025-6,275)5,614 (2,025-7,525)
Otariidae65 (65-65)65 (65-65)106 (100-110)137 (130-140)
Phocidae669 (650-725)669 (650-725)970 (900-1,025)1,075 (1,025-1,525)
1 Ranges to TTS represent the model predictions in different areas and seasons within the Study Area. The zone in which animals are expected to suffer TTS extend from onset-PTS to the distance indicated. The average range to TTS is provided as well as the range from the estimated minimum to the maximum range to TTS in parentheses.

Table 27—Ranges to Temporary Threshold Shift (Meters) for Sonar Bin MF4 Over a Representative Range of Environments Within the HSTT Study Area

Hearing groupApproximate TTS ranges (meters) 1
Sonar bin MF4 (e.g., AQS-22 ASW dipping sonar)
1 second30 seconds60 seconds120 seconds
Low-frequency Cetacean77 (0-85)162 (150-180)235 (220-290)370 (310-600)
Mid-frequency Cetacean22 (22-22)35 (35-35)49 (45-50)70 (70-70)
High-frequency Cetacean240 (220-300)492 (440-775)668 (550-1,025)983 (825-2,025)
Otariidae8 (8-8)15 (15-15)19 (19-19)25 (25-25)
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Phocidae65 (65-65)110 (110-110)156 (150-170)269 (240-460)
1 Ranges to TTS represent the model predictions in different areas and seasons within the Study Area. The zone in which animals are expected to suffer TTS extend from onset-PTS to the distance indicated. The average range to TTS is provided as well as the range from the estimated minimum to the maximum range to TTS in parentheses.

Table 28—Ranges to Temporary Threshold Shift (Meters) for Sonar Bin MF5 Over a Representative Range of Environments Within the HSTT Study Area

Hearing groupApproximate TTS ranges (meters) 1
Sonar bin MF5 (e.g., SSQ-62 ASW Sonobuoy)
1 second30 seconds60 seconds120 seconds
Low-frequency Cetacean10 (0-12)10 (0-12)14 (0-18)21 (0-25)
Mid-frequency Cetacean6 (0-9)6 (0-9)12 (0-13)17 (0-21)
High-frequency Cetacean118 (100-170)118 (100-170)179 (150-480)273 (210-700)
Otariidae0 (0-0)0 (0-0)0 (0-0)0 (0-0)
Phocidae9 (8-10)9 (8-10)14 (14-16)21 (21-25)
1 Ranges to TTS represent the model predictions in different areas and seasons within the Study Area. The zone in which animals are expected to suffer TTS extend from onset-PTS to the distance indicated. The average range to TTS is provided as well as the range from the estimated minimum to the maximum range to TTS in parentheses.

Table 29—Ranges to Temporary Threshold Shift (Meters) for Sonar Bin HF4 Over a Representative Range of Environments Within the HSTT Study Area

Hearing groupApproximate TTS ranges (meters) 1
Sonar bin HF4 (e.g., SQS-20 mine hunting sonar)
1 second30 seconds>60 seconds120 seconds
Low-frequency Cetacean1 (0-3)2 (0-5)4 (0-7)6 (0-11)
Mid-frequency Cetacean10 (4-17)17 (6-35)24 (7-60)34 (9-90)
High-frequency Cetacean168 (25-550)280 (55-775)371 (80-1,275)470 (100-1,525)
Otariidae0 (0-0)0 (0-0)0 (0-0)1 (0-1)
Phocidae2 (0-5)5 (2-8)8 (3-13)11 (4-22)
1 Ranges to TTS represent the model predictions in different areas and seasons within the Study Area. The zone in which animals are expected to suffer TTS extend from onset-PTS to the distance indicated. The average range to TTS is provided as well as the range from the estimated minimum to the maximum range to TTS in parentheses.

Explosives

The following section provides the range (distance) over which specific physiological or behavioral effects are expected to occur based on the explosive criteria (see Chapter 6, Section 6.5.2.1.1 of the Navy's rulemaking/LOA application and the Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis (Phase III) report (U.S. Department of the Navy, 2017c) and the explosive propagation calculations from the Navy Acoustic Effects Model (see Chapter 6, Section 6.5.2.1.3, Navy Acoustic Effects Model of the Navy's rulemaking/LOA application). The range to effects are shown for a range of explosive bins, from E1 (up to 0.25 lb net explosive weight) to E12 (up to 1,000 lb net explosive weight) (Tables 30 through 34). Ranges are determined by modeling the distance that noise from an explosion would need to propagate to reach exposure level thresholds specific to a hearing group that would cause behavioral response (to the degree of Level B behavioral harassment), TTS, PTS, and non-auditory injury. Ranges are provided for a representative source depth and cluster size for each bin. For events with multiple explosions, sound from successive explosions can be expected to accumulate and increase the range to the onset of an impact based on SEL thresholds. Ranges to non-auditory injury and mortality are shown in Tables 35 and 36, respectively. Range to effects is important information in not only predicting impacts from explosives, but also in verifying the accuracy of model results against real-world situations and determining adequate mitigation ranges to avoid higher level effects, especially physiological effects to marine mammals. For additional information on how ranges to impacts from Start Printed Page 66931explosions were estimated, see the technical report Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing (U.S. Navy, 2018).

Table 30 shows the minimum, average, and maximum ranges to onset of auditory and likely behavioral effects that rise to the level of Level B harassment for high-frequency cetaceans based on the developed thresholds.

Table 30—SEL-Based Ranges (Meters) to Onset PTS, Onset TTS, and Level B Behavioral Harassment for High-Frequency Cetaceans

Range to effects for explosives: High frequency cetacean 1
BinSource depth (m)Cluster sizePTSTTSBehavioral
E10.11353 (130-825)1,234 (290-3,025)2,141 (340-4,775)
251,188 (280-3,025)3,752 (490-8,525)5,196 (675-12,275)
E20.11425 (140-1,275)1,456 (300-3,525)2,563 (390-5,275)
10988 (280-2,275)3,335 (480-7,025)4,693 (650-10,275)
E30.11654 (220-1,525)2,294 (350-4,775)3,483 (490-7,775)
121,581 (300-3,525)4,573 (650-10,275)6,188 (725-14,775)
18.251747 (550-1,525)3,103 (950-6,025)5,641 (1,000-9,275)
121,809 (875-4,025)7,807 (1,025-12,775)10,798 (1,025-17,775)
E4322,020 (1,025-3,275)3,075 (1,025-6,775)3,339 (1,025-9,775)
15.252970 (600-1,525)4,457 (1,025-8,525)6,087 (1,275-12,025)
19.821,023 (1,000-1,025)4,649 (2,275-8,525)6,546 (3,025-11,025)
1982959 (875-1,525)4,386 (3,025-7,525)5,522 (3,025-9,275)
E50.1252,892 (440-6,275)6,633 (725-16,025)8,925 (800-22,775)
15.25254,448 (1,025-7,775)10,504 (1,525-18,275)13,605 (1,775-24,775)
E60.111,017 (280-2,525)3,550 (490-7,775)4,908 (675-12,275)
312,275 (2,025-2,525)6,025 (4,525-7,275)7,838 (6,275-9,775)
15.2511,238 (625-2,775)5,613 (1,025-10,525)7,954 (1,275-14,275)
E7313,150 (2,525-3,525)7,171 (5,525-8,775)8,734 (7,275-10,525)
18.2512,082 (925-3,525)6,170 (1,275-10,525)8,464 (1,525-16,525)
E80.111,646 (775-2,525)4,322 (1,525-9,775)5,710 (1,525-14,275)
45.7511,908 (1,025-4,775)5,564 (1,525-12,525)7,197 (1,525-18,775)
E90.112,105 (850-4,025)4,901 (1,525-12,525)6,700 (1,525-16,775)
E100.112,629 (875-5,275)5,905 (1,525-13,775)7,996 (1,525-20,025)
E1118.513,034 (1,025-6,025)7,636 (1,525-16,525)9,772 (1,775-21,525)
45.7512,925 (1,525-6,025)7,152 (2,275-18,525)9,011 (2,525-24,525)
E120.112,868 (975-5,525)6,097 (2,275-14,775)8,355 (4,275-21,275)
33,762 (1,525-8,275)7,873 (3,775-20,525)10,838 (4,275-26,525)
1 Average distance (m) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in parentheses. Values depict the range produced by SEL hearing threshold criteria levels.
E13 not modeled due to surf zone use and lack of marine mammal receptors at site-specific location.

Table 31 shows the minimum, average, and maximum ranges to onset of auditory and likely behavioral effects that rise to the level of Level B harassment for mid-frequency cetaceans based on the developed thresholds.

Table 31—SEL-Based Ranges (Meters) to Onset PTS, Onset TTS, and Level B Behavioral Harassment for Mid-Frequency Cetaceans

Range to effects for explosives: Mid-frequency cetacean 1
BinSource depth (m)Cluster sizePTSTTSBehavioral
E10.1125 (25-25)118 (80-210)178 (100-320)
25107 (75-170)476 (150-1,275)676 (240-1,525)
E20.1130 (30-35)145 (95-240)218 (110-400)
1088 (65-130)392 (140-825)567 (190-1,275)
E30.1150 (45-65)233 (110-430)345 (130-600)
12153 (90-250)642 (220-1,525)897 (270-2,025)
18.25138 (35-40)217 (190-900)331 (290-850)
12131 (120-250)754 (550-1,525)1,055 (600-2,525)
E432139 (110-160)1,069 (525-1,525)1,450 (875-1,775)
15.25271 (70-75)461 (400-725)613 (470-750)
19.8269 (65-70)353 (350-360)621 (600-650)
198249 (0-55)275 (270-280)434 (430-440)
E50.125318 (130-625)1,138 (280-3,025)1,556 (310-3,775)
15.2525312 (290-725)1,321 (675-2,525)1,980 (850-4,275)
E60.1198 (70-170)428 (150-800)615 (210-1,525)
31159 (150-160)754 (650-850)1,025 (1,025-1,025)
15.25188 (75-180)526 (450-875)719 (500-1,025)
Start Printed Page 66932
E731240 (230-260)1,025 (1,025-1,025)1,900 (1,775-2,275)
18.251166 (120-310)853 (500-1,525)1,154 (550-1,775)
E80.11160 (150-170)676 (500-725)942 (600-1,025)
45.751128 (120-170)704 (575-2,025)1,040 (750-2,525)
E90.11215 (200-220)861 (575-950)1,147 (650-1,525)
E100.11275 (250-480)1,015 (525-2,275)1,424 (675-3,275)
E1118.51335 (260-500)1,153 (650-1,775)1,692 (775-3,275)
45.751272 (230-825)1,179 (825-3,025)1,784 (1,000-4,275)
E120.11334 (310-350)1,151 (700-1,275)1,541 (800-3,525)
0.13520 (450-550)1,664 (800-3,525)2,195 (925-4,775)
1 Average distance (m) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in parentheses. Values depict the range produced by SEL hearing threshold criteria levels.
E13 not modeled due to surf zone use and lack of marine mammal receptors at site-specific location.

Table 32 shows the minimum, average, and maximum ranges to onset of auditory and likely behavioral effects that rise to the level of Level B harassment for low-frequency cetaceans based on the developed thresholds.

Table 32—SEL-Based Ranges (Meters) to Onset PTS, Onset TTS, and Level B Behavioral Harassment for Low-Frequency Cetaceans

Range to effects for explosives: Low frequency cetacean 1
BinSource depth (m)Cluster sizePTSTTSBehavioral
E10.1151 (40-70)227 (100-320)124 (70-160)
25205 (95-270)772 (270-1,275)476 (190-725)
E20.1165 (45-95)287 (120-400)159 (80-210)
10176 (85-240)696 (240-1,275)419 (160-625)
E30.11109 (65-150)503 (190-1,000)284 (120-430)
12338 (130-525)1,122 (320-7,775)761 (240-6,025)
18.251205 (170-340)996 (410-2,275)539 (330-1,275)
12651 (340-1,275)3,503 (600-8,275)1,529 (470-3,275)
E432493 (440-1,000)2,611 (1,025-4,025)1,865 (950-2,775)
15.252583 (350-850)3,115 (1,275-5,775)1,554 (1,000-2,775)
19.82378 (370-380)1,568 (1,275-1,775)926 (825-950)
1982299 (290-300)2,661 (1,275-3,775)934 (900-950)
E50.125740 (220-6,025)2,731 (460-22,275)1,414 (350-14,275)
15.25251,978 (1,025-5,275)8,188 (3,025-19,775)4,727 (1,775-11,525)
E60.11250 (100-420)963 (260-7,275)617 (200-1,275)
31711 (525-825)3,698 (1,525-4,275)2,049 (1,025-2,525)
15.251718 (390-2,025)3,248 (1,275-8,525)1,806 (950-4,525)
E7311,121 (850-1,275)5,293 (2,025-6,025)3,305 (1,275-4,025)
18.2511,889 (1,025-2,775)6,157 (2,775-11,275)4,103 (2,275-7,275)
E80.11460 (170-950)1,146 (380-7,025)873 (280-3,025)
45.7511,049 (550-2,775)4,100 (1,025-14,275)2,333 (800-7,025)
E90.11616 (200-1,275)1,560 (450-12,025)1,014 (330-5,025)
E100.11787 (210-2,525)2,608 (440-18,275)1,330 (330-9,025)
E1118.514,315 (2,025-8,025)10,667 (4,775-26,775)7,926 (3,275-21,025)
45.7511,969 (775-5,025)9,221 (2,525-29,025)4,594 (1,275-16,025)
E120.11815 (250-3,025)2,676 (775-18,025)1,383 (410-8,525)
0.131,040 (330-6,025)4,657 (1,275-31,275)2,377 (700-16,275)
1 Average distance (m) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances, which are in parentheses. Values depict the range produced by SEL hearing threshold criteria levels.
E13 not modeled due to surf zone use and lack of marine mammal receptors at site-specific location.

Table 33 shows the minimum, average, and maximum ranges to onset of auditory and likely behavioral effects that rise to the level of Level B harassment for phocids based on the developed thresholds.Start Printed Page 66933

Table 33—SEL-Based Ranges (Meters) to Onset PTS, Onset TTS, and Level B Behavioral Harassment for Phocids

Range to effects for explosives: Phocids 1
BinSource depth (m)Cluster sizePTSTTSBehavioral
E10.1145 (40-65)210 (100-290)312 (130-430)
25190 (95-260)798 (280-1,275)1,050 (360-2,275)
E20.1158 (45-75)258 (110-360)383 (150-550)
10157 (85-240)672 (240-1,275)934 (310-1,525)
E30.1196 (60-120)419 (160-625)607 (220-900)
12277 (120-390)1,040 (370-2,025)1,509 (525-6,275)
18.251118 (110-130)621 (500-1,275)948 (700-2,025)
12406 (330-875)1,756 (1,025-4,775)3,302 (1,025-6,275)
E432405 (300-430)1,761 (1,025-2,775)2,179 (1,025-3,275)
15.252265 (220-430)1,225 (975-1,775)1,870 (1,025-3,275)
19.82220 (220-220)991 (950-1,025)1,417 (1,275-1,525)
1982150 (150-150)973 (925-1,025)2,636 (2,025-3,525)
E50.125569 (200-850)2,104 (725-9,275)2,895 (825-11,025)
15.2525920 (825-1,525)5,250 (2,025-10,275)7,336 (2,275-16,025)
E60.11182 (90-250)767 (270-1,275)1,011 (370-1,775)
31392 (340-440)1,567 (1,275-1,775)2,192 (2,025-2,275)
15.251288 (250-600)1,302 (1,025-3,275)2,169 (1,275-5,775)
E731538 (450-625)2,109 (1,775-2,275)2,859 (2,775-3,275)
18.251530 (460-750)2,617 (1,025-4,525)3,692 (1,525-5,275)
E80.11311 (290-330)1,154 (625-1,275)1,548 (725-2,275)
45.751488 (380-975)2,273 (1,275-5,275)3,181 (1,525-8,025)
E90.11416 (350-470)1,443 (675-2,025)1,911 (800-3,525)
E100.11507 (340-675)1,734 (725-3,525)2,412 (800-5,025)
E1118.511,029 (775-1,275)5,044 (2,025-8,775)6,603 (2,525-14,525)
45.751881 (700-2,275)3,726 (2,025-8,775)5,082 (2,025-13,775)
E120.11631 (450-750)1,927 (800-4,025)2,514 (925-5,525)
0.13971 (550-1,025)2,668 (1,025-6,275)3,541 (1,775-9,775)
1 Average distance (m) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in parentheses. Values depict the range produced by SEL hearing threshold criteria levels.
E13 not modeled due to surf zone use and lack of marine mammal receptors at site-specific location.

Table 34 shows the minimum, average, and maximum ranges to onset of auditory and likely behavioral effects that rise to the level of Level B harassment for ottariids based on the developed thresholds.

Table 34—SEL-Based Ranges (Meters) to Onset PTS, Onset TTS, and Level B Behavioral Harassment for Otariids

Range to effects for explosives: Otariids 1
BinSource depth (m)Cluster sizePTSTTSBehavioral
E10.117 (7-7)34 (30-40)56 (45-70)
2530 (25-35)136 (80-180)225 (100-320)
E20.119 (9-9)41 (35-55)70 (50-95)
1025 (25-30)115 (70-150)189 (95-250)
E30.1116 (15-19)70 (50-95)115 (70-150)
1245 (35-65)206 (100-290)333 (130-450)
18.25115 (15-15)95 (90-100)168 (150-310)
1255 (50-60)333 (280-750)544 (440-1,025)
E43264 (40-85)325 (240-340)466 (370-490)
15.25230 (30-35)205 (170-300)376 (310-575)
19.8225 (25-25)170 (170-170)290 (290-290)
198217 (0-25)117 (110-120)210 (210-210)
E50.12598 (60-120)418 (160-575)626 (240-1,000)
15.2525151 (140-260)750 (650-1,025)1,156 (975-2,025)
E60.1130 (25-35)134 (75-180)220 (100-320)
3153 (50-55)314 (280-390)459 (420-525)
15.25136 (35-40)219 (200-380)387 (340-625)
E73193 (90-100)433 (380-500)642 (550-800)
18.25173 (70-75)437 (360-525)697 (600-850)
E80.1150 (50-50)235 (220-250)385 (330-450)
45.75155 (55-60)412 (310-775)701 (500-1,525)
E90.1168 (65-70)316 (280-360)494 (390-625)
Start Printed Page 66934
E100.1186 (80-95)385 (240-460)582 (390-800)
E1118.51158 (150-200)862 (750-975)1,431 (1,025-2,025)
45.751117 (110-130)756 (575-1,525)1,287 (950-2,775)
E120.11104 (100-110)473 (370-575)709 (480-1,025)
0.13172 (170-180)694 (480-1,025)924 (575-1,275)
1 Average distance (m) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in parentheses. Values depict the range produced by SEL hearing threshold criteria levels.
E13 not modeled due to surf zone use and lack of marine mammal receptors at site-specific location.

Table 35 shows the minimum, average, and maximum ranges due to varying propagation conditions to non-auditory injury as a function of animal mass and explosive bin (i.e., net explosive weight). Ranges to gastrointestinal tract injury typically exceed ranges to slight lung injury; therefore, the maximum range to effect is not mass-dependent. Animals within these water volumes would be expected to receive minor injuries at the outer ranges, increasing to more substantial injuries, and finally mortality as an animal approaches the detonation point.

Table 35—Ranges 1 to 50 Percent Non-Auditory Injury Risk for All Marine Mammal Hearing Groups

BinRange (m) (min-max)
E112 (11-13)
E215 (15-20)
E325 (25-30)
E432 (0-75)
E540 (35-140)
E652 (40-120)
E7145 (100-500)
E8117 (75-400)
E9120 (90-290)
E10174 (100-480)
E11443 (350-1,775)
E12232 (110-775)
Note:1 Average distance (m) to mortality is depicted above the minimum and maximum distances which are in parentheses.
E13 not modeled due to surf zone use and lack of marine mammal receptors at site-specific location. Differences between bins E11 and E12 due to different ordnance types and differences in model parameters.

Ranges to mortality, based on animal mass, are show in Table 36 below.

Table 36—Ranges 1 to 50 Percent Mortality Risk for All Marine Mammal Hearing Groups as a Function of Animal Mass

BinAnimal mass intervals (kg) 1
102501,0005,00025,000>72,000
E13 (2-3)0 (0-3)0 (0-0)0 (0-0)0 (0-0)0 (0-0)
E24 (3-5)1 (0-4)0 (0-0)0 (0-0)0 (0-0)0 (0-0)
E38 (6-10)4 (2-8)1 (0-2)0 (0-0)0 (0-0)0 (0-0)
E415 (0-35)9 (0-30)4 (0-8)2 (0-6)0 (0-3)0 (0-2)
E513 (11-45)7 (4-35)3 (3-12)2 (0-8)0 (0-2)0 (0-2)
E618 (14-55)10 (5-45)5 (3-15)3 (2-10)0 (0-3)0 (0-2)
E767 (55-180)35 (18-140)16 (12-30)10 (8-20)5 (4-9)4 (3-7)
E850 (24-110)27 (9-55)13 (0-20)9 (4-13)4 (0-6)3 (0-5)
E932 (30-35)20 (13-30)10 (8-12)7 (6-9)4 (3-4)3 (2-3)
E1056 (40-190)25 (16-130)13 (11-16)9 (7-11)5 (4-5)4 (3-4)
E11211 (180-500)109 (60-330)47 (40-100)30 (25-65)15 (0-25)13 (11-22)
E1294 (50-300)35 (20-230)16 (13-19)11 (9-13)6 (5-8)5 (4-8)
Note:1 Average distance (m) to mortality is depicted above the minimum and maximum distances which are in parentheses.
E13 not modeled due to surf zone use and lack of marine mammal receptors at site-specific location.
Differences between bins E11 and E12 due to different ordnance types and differences in model parameters (see Table 6-42 for details).
Start Printed Page 66935

Air Guns

Table 37 and Table 38 present the approximate ranges in meters to PTS, TTS, and likely behavioral responses that rise to the level of a take for air guns for 1 and 10 pulses, respectively. Ranges are specific to the HSTT Study Area and also to each marine mammal hearing group, dependent upon their criteria and the specific locations where animals from the hearing groups and the air gun activities could overlap. Small air guns (12-60 in3) would be used during testing activities in the offshore areas of the Southern California Range Complex and in the Hawaii Range Complex. Generated impulses would have short durations, typically a few hundred milliseconds, with dominant frequencies below 1 kHz. The SPL and SPL peak (at a distance 1 m from the air gun) would be approximately 215 dB re 1 µPa and 227 dB re 1 µPa, respectively, if operated at the full capacity of 60 in3. The size of the air gun chamber can be adjusted, which would result in lower SPLs and SEL per shot. Single, small air guns lack the peak pressures that could cause non-auditory injury (see Finneran et al., 2015); therefore, potential impacts could include PTS, TTS, and/or Level B behavioral harassment.

Table 37—Range to Effects (Meters) From Air Guns for 1 Pulse

Range to effects for air guns 1 for 1 pulse (m)
Hearing groupPTS (SEL)PTS (Peak SPL)TTS (SEL)TTS (Peak SPL)Behavioral 2
High-Frequency Cetacean0 (0-0)18 (15-25)1 (0-2)33 (25-80)702 (290-1,525)
Low-Frequency Cetacean3 (3-4)2 (2-3)27 (23-35)5 (4-7)651 (200-1,525)
Mid-Frequency Cetacean0 (0-0)0 (0-0)0 (0-0)0 (0-0)689 (290-1,525)
Otariidae0 (0-0)0 (0-0)0 (0-0)0 (0-0)590 (290-1,525)
Phocidae0 (0-0)2 (2-3)0 (0-0)5 (4-8)668 (290-1,525)
1 Average distance (m) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in parentheses. PTS and TTS values depict the range produced by SEL and Peak SPL (as noted) hearing threshold criteria levels.
2 Behavioral values depict the ranges produced by RMS hearing threshold criteria levels.

Table 38—Range to Effects (Meters) From Air Guns for 10 Pulses

Range to Effects for Air Guns 1 for 10 pulses (m)
Hearing groupPTS (SEL)PTS (Peak SPL)TTS (SEL)TTS (Peak SPL)Behavioral 2
High-Frequency Cetacean0 (0-0)18 (15-25)3 (0-9)33 (25-80)702 (290-1,525)
Low-Frequency Cetacean15 (12-20)2 (2-3)86 (70-140)5 (4-7)651 (200-1,525)
Mid-Frequency Cetacean0 (0-0)0 (0-0)0 (0-0)0 (0-0)689 (290-1,525)
Otariidae0 (0-0)0 (0-0)0 (0-0)0 (0-0)590 (290-1,525)
Phocidae0 (0-0)2 (2-3)4 (3-5)5 (4-8)668 (290-1,525)
1 Average distance (m) to PTS, TTS, and behavioral thresholds are depicted above the minimum and maximum distances which are in parentheses. PTS and TTS values depict the range produced by SEL and Peak SPL (as noted) hearing threshold criteria levels.
2 Behavioral values depict the ranges produced by RMS hearing threshold criteria levels.

Pile Driving

Table 39 and Table 40 present the approximate ranges in meters to PTS, TTS, and/or Level B behavioral harassment that rise to the level of a take for impact pile driving and vibratory pile removal, respectively. Non-auditory injury is not predicted for pile driving activities.

Table 39—Average Ranges to Effects (Meters) From Impact Pile Driving

Hearing groupPTS (m)TTS (m)Behavioral (m)
Low-Frequency Cetaceans65529870
Mid-Frequency Cetaceans216870
High-Frequency Cetaceans65529870
Phocidae19151870
Otariidae212870
Note: PTS: permanent threshold shift; TTS: temporary threshold shift.

Table 40—Average Ranges to Effect (Meters) From Vibratory Pile Extraction

Hearing groupPTS (m)TTS (m)Behavioral (m)
Low-Frequency Cetaceans03376
Mid-Frequency Cetaceans04376
High-Frequency Cetaceans7116376
Phocidae02376
Otariidae00376
Note: PTS: permanent threshold shift; TTS: temporary threshold shift.
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Marine Mammal Density

A quantitative analysis of impacts on a species or stock requires data on their abundance and distribution that may be affected by anthropogenic activities in the potentially impacted area. The most appropriate metric for this type of analysis is density, which is the number of animals present per unit area. Marine species density estimation requires a significant amount of effort to both collect and analyze data to produce a reasonable estimate. Unlike surveys for terrestrial wildlife, many marine species spend much of their time submerged, and are not easily observed. In order to collect enough sighting data to make reasonable density estimates, multiple observations are required, often in areas that are not easily accessible (e.g., far offshore). Ideally, marine mammal species sighting data would be collected for the specific area and time period (e.g., season) of interest and density estimates derived accordingly. However, in many places, poor weather conditions and high sea states prohibit the completion of comprehensive visual surveys.

For most cetacean species, abundance is estimated using line-transect surveys or mark-recapture studies (e.g., Barlow, 2010; Barlow and Forney, 2007; Calambokidis et al., 2008). The result provides one single density estimate value for each species across broad geographic areas. This is the general approach applied in estimating cetacean abundance in the NMFS' SARs. Although the single value provides a good average estimate of abundance (total number of individuals) for a specified area, it does not provide information on the species distribution or concentrations within that area, and it does not estimate density for other timeframes or seasons that were not surveyed. More recently, spatial habitat modeling developed by NMFS' Southwest Fisheries Science Center has been used to estimate cetacean densities (Barlow et al., 2009; Becker et al., 2010, 2012a, b, c, 2014, 2016; Ferguson et al., 2006a; Forney et al., 2012, 2015; Redfern et al., 2006). These models estimate cetacean density as a continuous function of habitat variables (e.g., sea surface temperature, seafloor depth, etc.) and thus allow predictions of cetacean densities on finer spatial scales than traditional line-transect or mark recapture analyses and for areas that have not been surveyed. Within the geographic area that was modeled, densities can be predicted wherever these habitat variables can be measured or estimated.

To characterize the marine species density for large areas such as the HSTT Study Area, the Navy compiled data from several sources. The Navy developed a protocol to select the best available data sources based on species, area, and time (season). The resulting Geographic Information System database, called the Navy Marine Species Density Database includes seasonal density values for every marine mammal species present within the HSTT Study Area. This database is described in the technical report titled U.S. Navy Marine Species Density Database Phase III for the Hawaii-Southern California Training and Testing Study Area (U.S. Department of the Navy, 2017e), hereafter referred to as the Density Technical Report.

A variety of density data and density models are needed in order to develop a density database that encompasses the entirety of the HSTT Study Area. Because this data is collected using different methods with varying amounts of accuracy and uncertainty, the Navy has developed a hierarchy to ensure the most accurate data is used when available. The Density Technical Report describes these models in detail and provides detailed explanations of the models applied to each species density estimate. The below list describes models in order of preference.

1. Spatial density models are preferred and used when available because they provide an estimate with the least amount of uncertainty by deriving estimates for divided segments of the sampling area. These models (see Becker e t al., 2016; Forney et al., 2015) predict spatial variability of animal presence as a function of habitat variables (e.g., sea surface temperature, seafloor depth, etc.). This model is developed for areas, species, and, when available, specific timeframes (months or seasons) with sufficient survey data; therefore, this model cannot be used for species with low numbers of sightings.

2. Stratified design-based density estimates use line-transect survey data with the sampling area divided (stratified) into sub-regions, and a density is predicted for each sub-region (see Barlow, 2016; Becker et al., 2016; Bradford et al., 2017; Campbell et al., 2014; Jefferson et al., 2014). While geographically stratified density estimates provide a better indication of a species' distribution within the study area, the uncertainty is typically high because each sub-region estimate is based on a smaller stratified segment of the overall survey effort.

3. Design-based density estimations use line-transect survey data from land and aerial surveys designed to cover a specific geographic area (see Carretta et al., 2015). These estimates use the same survey data as stratified design-based estimates, but are not segmented into sub-regions and instead provide one estimate for a large surveyed area. Although relative environmental suitability (RES) models provide estimates for areas of the oceans that have not been surveyed using information on species occurrence and inferred habitat associations and have been used in past density databases, these models were not used in the current quantitative analysis. In the HSTT analysis, due to the availability of other density methods along the hierarchy the use of RES model was not necessary.

When interpreting the results of the quantitative analysis, as described in the Density Technical Report, “it is important to consider that even the best estimate of marine species density is really a model representation of the values of concentration where these animals might occur. Each model is limited to the variables and assumptions considered by the original data source provider. No mathematical model representation of any biological population is perfect, and with regards to marine mammal biodiversity, any single model method will not completely explain the actual distribution and abundance of marine mammal species. It is expected that there would be anomalies in the results that need to be evaluated, with independent information for each case, to support if we might accept or reject a model or portions of the model (U.S. Department of the Navy, 2017a).”

The Navy's estimate of abundance (based on the density estimates used) in the HSTT Study Area may differ from population abundances estimated in the NMFS' SARS in some cases for a variety of reasons. Models may predict different population abundances for many reasons, including being based on different data sets, different areas, or different time periods. The SARs are often based on single years of NMFS surveys, whereas the models used by the Navy generally include multiple years of survey data from NMFS, the Navy, and other sources. To present a single, best estimate, the SARs often use a single season survey where they have the best spatial coverage (generally Summer). Navy models often use predictions for multiple seasons, where appropriate for the species, even when survey coverage in non-Summer seasons is limited, to characterize impacts over multiple seasons as Navy activities may occur in any season. Predictions may be made for different spatial extents. For Start Printed Page 66937example, the SAR encompasses the U.S. EEZ, while the HSTT Study area overlaps only part of the U.S. EEZ (specifically, the Pacific SAR overlaps only 35 percent of the Hawaii part of the HSTT Study Area and only about 14 percent of SOCAL), but alternately extends out significantly beyond it to the West. Many different, but equally valid, habitat and density modeling techniques exist and these can also be the cause of differences in population predictions. Differences in population estimates may be caused by a combination of these factors. Even similar estimates should be interpreted with caution and differences in models fully understood before drawing conclusions.

The global population structure of humpbacks, with 14 DPSs all associated with multiple feeding areas at which individuals from multiple DPSs convene, is another reason that SAR abundance estimates can differ from other estimates and be somewhat confusing—the same individuals are addressed in multiple SARs. For some species, the stock assessment for a given species may exceed the Navy's density prediction because those species' home range extends beyond the Study Area boundaries. For other species, the stock assessment abundance may be much less than the number of animals in the Navy's modeling because the HSTT Study Area extends well beyond the U.S. waters covered by the SAR abundance estimate. The primary source of density estimates are geographically specific survey data and either peer-reviewed line-transect estimates or habitat-based density models that have been extensively validated to provide the most accurate estimates possible.

These factors and others described in the Density Technical Report should be considered when examining the estimated impact numbers in comparison to current population abundance information for any given species or stock. For a detailed description of the density and assumptions made for each species, see the Density Technical Report.

NMFS coordinated with the Navy in the development of its take estimates and concurs that the Navy's approach for density appropriately utilizes the best available science. Later, in the Analysis and Negligible Impact Determination section, we assess how the estimated take numbers compare to stock abundance in order to better understand the potential number of individuals impacted, and the rationale for which abundance estimate is used is included there.

Take Requests

The HSTT FEIS/OEIS considered all training and testing activities proposed to occur in the HSTT Study Area that have the potential to result in the MMPA defined take of marine mammals. The Navy determined that the three stressors below could result in the incidental taking of marine mammals. NMFS has reviewed the Navy's data and analysis and determined that it is complete and accurate and agrees that the following stressors have the potential to result in takes of marine mammals from the Navy's planned activities.

  • Acoustics (sonar and other transducers; air guns; pile driving/extraction).
  • Explosives (explosive shock wave and sound (assumed to encompass the risk due to fragmentation)).
  • Physical Disturbance and Strike (vessel strike).

NMFS reviewed, and agrees with, the Navy's conclusion that acoustic and explosive sources have the potential to result in incidental takes of marine mammals by harassment, serious injury, or mortality. NMFS carefully reviewed the Navy's analysis and conducted its own analysis of vessel strikes, determining that the likelihood of any particular species of large whale being struck is quite low. Nonetheless, NMFS agrees that vessel strikes have the potential to result in incidental take from serious injury or mortality for certain species of large whales and the Navy has specifically requested coverage for these species. Therefore, the likelihood of vessel strikes, and later the effects of the incidental take that is being authorized, has been fully analyzed and is described below.

The quantitative analysis process used for the HSTT FEIS/OEIS and the Navy's take request in the rulemaking/LOA application to estimate potential exposures to marine mammals resulting from acoustic and explosive stressors is detailed in the technical report titled Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing report (U.S. Department of the Navy, 2018). The Navy Acoustic Effects Model estimates acoustic and explosive effects without taking mitigation into account; therefore, the model overestimates predicted impacts on marine mammals within mitigation zones. To account for mitigation for marine species in the take estimates, the Navy conducts a quantitative assessment of mitigation. The Navy conservatively quantifies the manner in which mitigation is expected to reduce model-estimated PTS to TTS for exposures to sonar and other transducers, and reduce model-estimated mortality to injury for exposures to explosives. The extent to which the mitigation areas reduce impacts on the affected species and stocks is addressed separately in the Analysis and Negligible Impact Determination section.

The Navy assessed the effectiveness of its procedural mitigation measures on a per-scenario basis for four factors: (1) Species sightability, (2) a Lookout's ability to observe the range to PTS (for sonar and other transducers) and range to mortality (for explosives), (3) the portion of time when mitigation could potentially be conducted during periods of reduced daytime visibility (to include inclement weather and high sea-state) and the portion of time when mitigation could potentially be conducted at night, and (4) the ability for sound sources to be positively controlled (e.g., powered down).

During training and testing activities, there is typically at least one, if not numerous, support personnel involved in the activity (e.g., range support personnel aboard a torpedo retrieval boat or support aircraft). In addition to the Lookout posted for the purpose of mitigation, these additional personnel observe and disseminate marine species sighting information amongst the units participating in the activity whenever possible as they conduct their primary mission responsibilities. However, as a conservative approach to assigning mitigation effectiveness factors, the Navy elected to only account for the minimum number of required Lookouts used for each activity; therefore, the mitigation effectiveness factors may underestimate the likelihood that some marine mammals may be detected during activities that are supported by additional personnel who may also be observing the mitigation zone.

The Navy used the equations in the below sections to calculate the reduction in model-estimated mortality impacts due to implementing procedural mitigation.

Equation 1:

Mitigation Effectiveness = Species Sightability × Visibility × Observation Area × Positive Control

Species Sightability is the ability to detect marine mammals and is dependent on the animal's presence at the surface and the characteristics of the animal that influence its sightability. The Navy considered applicable data from the best available science to numerically approximate the sightability of marine mammals and Start Printed Page 66938determined the standard “detection probability” referred to as g(0) is most appropriate. Also, Visibility = 1 − sum of individual visibility reduction factors; Observation Area = portion of impact range that can be continuously observed during an event; and Positive Control = positive control factor of all sound sources involving mitigation. For further details on these mitigation effectiveness factors please refer to the technical report titled Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing report (U.S. Department of the Navy, 2018).

To quantify the number of marine mammals predicted to be sighted by Lookouts during implementation of procedural mitigation in the range to injury (PTS) for sonar and other transducers, the species sightability is multiplied by the mitigation effectiveness scores and number of model-estimated PTS impacts, as shown in the equation below:

Equation 2:

Number of Animals Sighted by Lookouts = Mitigation Effectiveness × Model-Estimated Impacts

The marine mammals sighted by Lookouts during implementation of mitigation in the range to PTS, as calculated by the equation above, would avoid being exposed to these higher level impacts. To quantify the number of marine mammals predicted to be sighted by Lookouts during implementation of procedural mitigation in the range to mortality during events using explosives, the species sightability is multiplied by the mitigation effectiveness scores and number of model-estimated mortality impacts, as shown in equation 1 above. The marine mammals predicted to be sighted by Lookouts during implementation of procedural mitigation in the range to mortality, as calculated by the above equation 2, are predicted to avoid exposure in these ranges. The Navy corrects the category of predicted impact for the number of animals sighted within the mitigation zone, but does not modify the total number of animals predicted to experience impacts from the scenario. For example, the number of animals sighted (i.e., number of animals that will avoid mortality) is first subtracted from the model-predicted mortality impacts, and then added to the model-predicted injurious impacts.

NMFS coordinated with the Navy in the development of this quantitative method to address the effects of procedural mitigation on acoustic and explosive exposures and takes, and NMFS independently reviewed and concurs with the Navy that it is appropriate to incorporate the quantitative assessment of mitigation into the take estimates based on the best available science. For additional information on the quantitative analysis process and mitigation measures, refer to the technical report titled Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing report (U.S. Department of the Navy, 2018) and Chapter 6 (Take Estimates for Marine Mammals) and Chapter 11 (Mitigation Measures) of the Navy's rulemaking/LOA application.

In summary, we believe the Navy's methods, including the method for incorporating mitigation and avoidance, are the most appropriate methods for predicting PTS and TTS. But even with the consideration of mitigation and avoidance, given some of the more conservative components of the methodology (e.g., the thresholds do not consider ear recovery between pulses), we would describe the application of these methods as identifying the maximum number of instances in which marine mammals would be reasonably expected to incur either TTS or PTS.

Summary of Requested Take From Training and Testing Activities

As a general matter, NMFS does not prescribe the methods for estimating take for any applicant, but we review and ensure that applicants use the best available science, and methodologies that are logical and technically sound. Applicants may use different methods of calculating take (especially when using models) and still get to a result that is representative of the best available science and that allows for a rigorous and accurate evaluation of the effects on the affected populations. There are multiple pieces of the Navy take estimation methods—propagation models, animat animal movement models, and behavioral thresholds, for example. NMFS evaluates the acceptability of these pieces as they evolve and are used in different rules and impact analyses. Some of the pieces of the Navy's take estimation process have been used in their rules since 2009 and undergone multiple public comment processes, all of them have undergone extensive internal Navy review, and all of them have undergone comprehensive review by NMFS, which has sometimes resulted in modifications to methods or models.

The Navy uses rigorous review processes (verification, validation, and accreditation processes, peer and public review) to ensure the data and methodology it uses represent the best available science. For instance, the NAEMO (animal movement) model is the result of a NMFS-led Center for Independent Experts (CIE) review of the components used in earlier models. The acoustic propagation component of the NAEMO model (CASS/GRAB) is accredited by the Oceanographic and Atmospheric Master Library (OAML), and many of the environmental variables used in the NAEMO model come from approved OAML databases and are based on in-situ data collection. The animal density components of the NAEMO model are base products of the Navy Marine Species Density Database, which includes animal density components that have been validated and reviewed by a variety of scientists from NMFS Science Centers and academic institutions. Several components of the model, for example the Duke University habitat-based density models, have been published in peer reviewed literature. Others like AMAPPS, which was conducted by NMFS Science Centers, have undergone quality assurance and quality control (QA/QC) processes. Finally the NAEMO model simulation components underwent QA/QC review and validation for model parts such as the scenario builder, acoustic builder, scenario simulator, etc., conducted by qualified statisticians and modelers to ensure accuracy. Other models and methodologies have gone through similar review processes.

Based on the methods discussed in the previous sections and the Navy's model and the quantitative assessment of mitigation, the Navy provided its take request for acoustic and explosive sources for training and testing activities both annually (based on the maximum number of activities per 12-month period) and over a 5-year period. NMFS has reviewed the Navy's data and analysis and determined that it is complete and accurate and that the takes by harassment as well as the takes by serious injury or mortality from explosives requested for authorization are reasonably expected to occur and that the takes by serious injury or mortality could occur as a result of vessel strikes. Five-year total impacts may be less than the sum total of each year because although the annual estimates are based on the maximum estimated takes, five-year estimates are based on the sum of two maximum years and three nominal years.Start Printed Page 66939

Authorized Take From Training Activities

For training activities, Table 41 summarizes the Navy's take request and the maximum amount and type of Level A and Level B harassment that NMFS concurs is reasonably likely to occur by species or stock. Authorized mortality is addressed further below. Navy Figures 6-12 through 6-50 in Chapter 6 of the Navy's rulemaking/LOA application illustrate the comparative amounts of TTS and Level B behavioral harassment for each species, noting that if a “taken” animat was exposed to both TTS and Level B behavioral harassment, it was recorded as a TTS.

Table 41—Species and Stock-Specific Take From Acoustic and Explosive Effects for All Training Activities in the HSTT Study Area

SpeciesStockAnnual5-Year total **
Level B harassmentLevel A harassmentLevel B harassmentLevel A harassment
Suborder Mysticeti (baleen whales)
Family Balaenopteridae (rorquals)
Blue whale *Central North Pacific3401390
Eastern North Pacific1,15515,0363
Bryde's whale †Eastern Tropical Pacific2701180
Hawaii †10504290
Fin whale *CA/OR/WA1,24505,4820
Hawaii3301330
Humpback whale †CA/OR/WA †1,25415,6453
Central North Pacific5,604123,6546
Minke whaleCA/OR/WA64912,9204
Hawaii3,463113,6642
Sei whale *Eastern North Pacific5302360
Hawaii11804530
Family Eschrichtiidae
Gray whale †Eastern North Pacific2,751511,86019
Western North Pacific †40140
Suborder Odontoceti (toothed whales)
Family Physeteridae (sperm whale)
Sperm whale *CA/OR/WA1,39706,2570
Hawaii1,71407,0780
Family Kogiidae (sperm whales)
Dwarf sperm whaleHawaii13,9613557,571148
Pygmy sperm whaleHawaii5,5561622,83364
Kogia whalesCA/OR/WA6,0122327,366105
Family Ziphiidae (beaked whales)
Baird's beaked whaleCA/OR/WA1,31706,0440
Blainville's beaked whaleHawaii3,687016,3640
Cuvier's beaked whaleCA/OR/WA7,016033,4940
Hawaii1,23505,4970
Longman's beaked whaleHawaii13,010057,1720
Mesoplodon sppCA/OR/WA3,778018,0360
Family Delphinidae (dolphins)
Bottlenose dolphinCalifornia Coastal21408760
CA/OR/WA Offshore31,9862142,9669
Hawaii Pelagic2,08609,0550
Kauai & Niihau7403560
Oahu8,186140,9187
4-Island15207500
Hawaii Island4202070
False killer whale †Hawaii Pelagic70103,0050
Main Hawaiian Islands Insular †40501,9150
Northwestern Hawaiian Islands25601,0940
Fraser's dolphinHawaii28,4091122,7843
Killer whaleEastern North Pacific Offshore7303260
Eastern North Pacific Transient/West Coast Transient13506060
Hawaii8403520
Start Printed Page 66940
Long-beaked common dolphinCalifornia128,99414559,54069
Melon-headed whaleHawaiian Islands2,33509,7050
Kohala Resident18209130
Northern right whale dolphinCA/OR/WA56,8208253,06840
Pacific white-sided dolphinCA/OR/WA43,9143194,88212
Pantropical spotted dolphinHawaii Island2,585012,6030
Hawaii Pelagic6,809029,2070
Oahu4,127020,6100
4-Island26001,2950
Pygmy killer whaleHawaii5,816024,4280
Tropical47102,1050
Risso's dolphinCA/OR/WA76,2766338,56030
Hawaii6,590028,1430
Rough-toothed dolphinHawaii4,292018,5060
NSD 10000
Short-beaked common dolphinCA/OR/WA932,453454,161,283216
Short-finned pilot whaleCA/OR/WA99014,4925
Hawaii8,594037,0770
Spinner dolphinHawaii Island8904330
Hawaii Pelagic3,138012,8260
Kauai & Niihau31001,3870
Oahu & 4-Island1,49317,4455
Striped dolphinCA/OR/WA119,2191550,9363
Hawaii5,388022,5260
Family Phocoenidae (porpoises)
Dall's porpoiseCA/OR/WA27,282137121,256634
Suborder Pinnipedia
Family Otariidae (eared seals)
California sea lionU.S69,54390327,136447
Guadalupe fur seal *Mexico51802,3860
Northern fur sealCalifornia9,786044,0170
Family Phocidae (true seals)
Harbor sealCalifornia3,119713,63634
Hawaiian monk seal *Hawaii13916623
Northern elephant sealCalifornia38,16972170,926349
Note: Kogia: Pygmy and dwarf sperm whales are difficult to distinguish between at sea, and abundance estimates are only available for Kogia spp (reported in Barlow 2016 and Carretta et al. 2017). Due to low estimated abundances of CA/OR/WA dwarf sperm whales, the majority of Kogia in the HSTT Study Area are anticipated to be CA/OR/WA pygmy sperm whales.
Mesoplodon: No methods are available to distinguish between the six species of Mesoplodon beaked whales in the CA/OR/WA stocks (Blainville's beaked whale (M. densirostris), Perrin's beaked whale (M. perrini), Lesser beaked whale (M. peruvianus), Stejneger's beaked whale (M. stejnegeri), Gingko-toothed beaked whale (M. gingkodens), and Hubbs' beaked whale (M. carlhubbsi)) when observed during at-sea surveys (Carretta et al., 2018). These six species are managed as one unit.
* ESA-listed species (all stocks) within the HSTT Study Area.
** 5-year total impacts may be less than sum total of each year. Not all activities occur every year; some activities occur multiple times within a year; and some activities only occur a few times over course of a 5-year period.
† Only designated stocks are ESA-listed.
1 NSD: No stock designation.

Authorized Take From Testing Activities

For testing activities, Table 42 summarizes the Navy's take request and the maximum amount and type of take by Level A and Level B harassment that NMFS concurs is reasonably likely to occur and has authorized by species or stock. Navy Figures 6-12 through 6-50 in Chapter 6 of the Navy's rulemaking/LOA application illustrate the comparative amounts of TTS and Level B behavioral harassment for each species, noting that if a “taken” animat was exposed to both TTS and Level B behavioral harassment in the model, it was recorded as a TTS.Start Printed Page 66941

Table 42—Species and Stock-Specific Take From Acoustic and Explosive Sound Source Effects for All Testing Activities in the HSTT Study Area

SpeciesStockAnnual5-year total **
Level B harassmentLevel A harassmentLevel B harassmentLevel A harassment
Suborder Mysticeti (baleen whales)
Family Balaenopteridae (rorquals)
Blue whale *Central North Pacific140650
Eastern North Pacific83304,0050
Bryde's whale †Eastern Tropical Pacific140690
Hawaii †4101940
Fin whale *CA/OR/WA98014,6953
Hawaii150740
Humpback whale †CA/OR/WA †74003,5080
Central North Pacific3,522216,77711
Minke whaleCA/OR/WA27601,3090
Hawaii1,46716,9184
Sei whale *Eastern North Pacific2601240
Hawaii4902290
Family Eschrichtiidae
Gray whale †Eastern North Pacific1,92029,2777
Western North Pacific †20110
Suborder Odontoceti (toothed whales)
Family Physeteridae (sperm whale)
Sperm whale *CA/OR/WA1,09605,2590
Hawaii78203,7310
Family Kogiidae (sperm whales)
Dwarf sperm whaleHawaii6,4592930,607140
Pygmy sperm whaleHawaii2,5951312,27060
Kogia whalesCA/OR/WA3,1201514,64367
Family Ziphiidae (beaked whales)
Baird's beaked whaleCA/OR/WA72703,4180
Blainville's beaked whaleHawaii1,69808,1170
Cuvier's beaked whaleCA/OR/WA4,484121,37920
Hawaii56102,6750
Longman's beaked whaleHawaii6,223029,7460
Mesoplodon sppCA/OR/WA2,415111,51211
Family Delphinidae (dolphins)
Bottlenose dolphinCalifornia Coastal1,59507,9680
CA/OR/WA Offshore23,4361112,4104
Hawaii Pelagic1,24206,0130
Kauai & Niihau49102,1610
Oahu47502,2940
4-Island20707780
Hawaii Island3801860
False killer whale †Hawaii Pelagic34001,6220
Main Hawaiian Islands Insular †18408920
Northwestern Hawaiian Islands12505940
Fraser's dolphinHawaii12,664160,3456
Killer whaleEastern North Pacific Offshore3401660
Eastern North Pacific Transient/West Coast Transient6403090
Hawaii4001980
Long-beaked common dolphinCalifornia118,2786568,02024
Melon-headed whaleHawaiian Islands1,15705,4230
Kohala Resident16807950
Northern right whale dolphinCA/OR/WA41,2793198,91715
Pacific white-sided dolphinCA/OR/WA31,4242151,0008
Pantropical spotted dolphinHawaii Island1,40906,7910
Hawaii Pelagic3,640017,6150
Oahu20209570
Start Printed Page 66942
4-Island45801,7340
Pygmy killer whaleHawaii2,708013,0080
Tropical28901,3510
Risso's dolphinCA/OR/WA49,9853240,64616
Hawaii2,808013,4950
Rough-toothed dolphinHawaii2,193010,5320
NSD 10000
Short-beaked common dolphinCA/OR/WA560,120442,673,431216
Short-finned pilot whaleCA/OR/WA92304,4400
Hawaii4,338020,7570
Spinner dolphinHawaii Island20209930
Hawaii Pelagic1,39606,7700
Kauai & Niihau1,43606,5300
Oahu & 4-Island33101,3890
Striped dolphinCA/OR/WA56,0352262,97311
Hawaiian2,396011,5460
Family Phocoenidae (porpoises)
Dall's porpoiseCA/OR/WA17,0917281,611338
Suborder Pinnipedia
Family Otariidae (eared seals)
California sea lionU.S.48,6656237,87023
Guadalupe fur seal *Mexico93904,3570
Northern fur sealCalifornia5,505126,1684
Family Phocidae (true seals)
Harbor sealCalifornia2,325111,2587
Hawaiian monk seal *Hawaii6602540
Northern elephant sealCalifornia22,70227107,343131
Note: Kogia: Pygmy and dwarf sperm whales are difficult to distinguish between at sea, and abundance estimates are only available for Kogia spp (reported in Barlow 2016 and Carretta et al. 2017). Due to low estimated abundances of CA/OR/WA dwarf sperm whales, the majority of Kogia in the HSTT Study Area are anticipated to be CA/OR/WA pygmy sperm whales.
Mesoplodon: No methods are available to distinguish between the six species of Mesoplodon beaked whales in the CA/OR/WA stocks (Blainville's beaked whale (M. densirostris), Perrin's beaked whale (M. perrini), Lesser beaked whale (M. peruvianus), Stejneger's beaked whale (M. stejnegeri), Gingko-toothed beaked whale (M. gingkodens), and Hubbs' beaked whale (M. carlhubbsi)) when observed during at-sea surveys (Carretta et al., 2018). These six species are managed as one unit.
* ESA-listed species (all stocks) within the HSTT Study Area.
** 5-year total impacts may be less than sum total of each year. Not all activities occur every year; some activities occur multiple times within a year; and some activities only occur a few times over course of a 5-year period.
† Only designated stocks are ESA-listed.
1 NSD: No stock designation.

Take From Vessel Strikes and Explosives by Serious Injury or Mortality

Vessel Strike

Vessel strikes from commercial, recreational, and military vessels are known to affect large whales and have resulted in serious injury and occasional fatalities to cetaceans (Berman-Kowalewski et al., 2010; Calambokidis, 2012; Douglas et al., 2008; Laggner 2009; Lammers et al., 2003). Records of collisions date back to the early 17th century, and the worldwide number of collisions appears to have increased steadily during recent decades (Laist et al., 2001; Ritter 2012).

Numerous studies of interactions between surface vessels and marine mammals have demonstrated that free-ranging marine mammals often, but not always (e.g., McKenna et al., 2015), engage in avoidance behavior when surface vessels move toward them. It is not clear whether these responses are caused by the physical presence of a surface vessel, the underwater noise generated by the vessel, or an interaction between the two (Amaral and Carlson, 2005; Au and Green, 2000; Bain et al., 2006; Bauer, 1986; Bejder et al., 1999; Bejder and Lusseau, 2008; Bejder et al., 2009; Bryant et al., 1984; Corkeron, 1995; Erbe, 2002; Félix, 2001; Goodwin and Cotton, 2004; Lemon et al., 2006; Lusseau, 2003; Lusseau, 2006; Magalhaes et al., 2002; Nowacek et al., 2001; Richter et al., 2003; Scheidat et al., 2004; Simmonds, 2005; Watkins, 1986; Williams et al., 2002; Wursig et al., 1998). Several authors suggest that the noise generated during motion is probably an important factor (Blane and Jaakson, 1994; Evans et al., 1992; Evans et al., 1994). Water disturbance may also be a factor. These studies suggest that the behavioral responses of marine mammals to surface vessels are similar to their behavioral responses to predators. Avoidance behavior is expected to be even stronger in the subset of instances that the Navy is Start Printed Page 66943conducting training or testing activities using active sonar or explosives.

The most vulnerable marine mammals are those that spend extended periods of time at the surface in order to restore oxygen levels within their tissues after deep dives (e.g., sperm whales). In addition, some baleen whales seem generally unresponsive to vessel sound, making them more susceptible to vessel collisions (Nowacek et al., 2004). These species are primarily large, slow moving whales.

Some researchers have suggested the relative risk of a vessel strike can be assessed as a function of animal density and the magnitude of vessel traffic (e.g., Fonnesbeck et al., 2008; Vanderlaan et al., 2008). Differences among vessel types also influence the probability of a vessel strike. The ability of any ship to detect a marine mammal and avoid a collision depends on a variety of factors, including environmental conditions, ship design, size, speed, and ability and number of personnel observing, as well as the behavior of the animal. Vessel speed, size, and mass are all important factors in determining if injury or death of a marine mammal is likely due to a vessel strike. For large vessels, speed and angle of approach can influence the severity of a strike. For example, Vanderlaan and Taggart (2007) found that between vessel speeds of 8.6 and 15 knots, the probability that a vessel strike is lethal increases from 0.21 to 0.79. Large whales also do not have to be at the water's surface to be struck. Silber et al. (2010) found when a whale is below the surface (about one to two times the vessel draft), there is likely to be a pronounced propeller suction effect. This suction effect may draw the whale into the hull of the ship, increasing the probability of propeller strikes.

There are some key differences between the operation of military and non-military vessels, which make the likelihood of a military vessel striking a whale lower than some other vessels (e.g., commercial merchant vessels). Key differences include:

Many military ships have their bridges positioned closer to the bow, offering better visibility ahead of the ship (compared to a commercial merchant vessel).

There are often aircraft associated with the training or testing activity (which can serve as Lookouts), which can more readily detect cetaceans in the vicinity of a vessel or ahead of a vessel's present course before crew on the vessel would be able to detect them.

Military ships are generally more maneuverable than commercial merchant vessels, and if cetaceans are spotted in the path of the ship, could be capable of changing course more quickly.

The crew size on military vessels is generally larger than merchant ships, allowing for stationing more trained Lookouts on the bridge. At all times when vessels are underway, trained Lookouts and bridge navigation teams are used to detect objects on the surface of the water ahead of the ship, including cetaceans. Additional Lookouts, beyond those already stationed on the bridge and on navigation teams, are positioned as Lookouts during some training events.

When submerged, submarines are generally slow moving (to avoid detection) and therefore marine mammals at depth with a submarine are likely able to avoid collision with the submarine. When a submarine is transiting on the surface, there are Lookouts serving the same function as they do on surface ships.

Vessel strike to marine mammals is not associated with any specific training or testing activity but is rather an extremely limited and sporadic, but possible, accidental result of Navy vessel movement within the HSTT Study Area or while in transit.

There have been two recorded Navy vessel strikes of large whales in the HSTT Study Area from 2009 through 2018, the period in which Navy began implementing effective mitigation measures to reduce the likelihood of vessel strikes. Both strikes occured in 2009 and both were to fin whales. In order to account for the accidental nature of vessel strikes to large whales in general, and the potential risk from any vessel movement within the HSTT Study Area within the five-year period in particular, the Navy requested incidental takes based on probabilities derived from a Poisson distribution using ship strike data between 2009-2016 in the HSTT Study Area (the time period from when current mitigations were instituted until the Navy conducted the analysis for the EIS/OEIS and rulemaking/LOA application; no new strikes have occurred since), as well as historical at-sea days in the HSTT Study Area from 2009-2016 and estimated potential at-sea days for the period from 2018 to 2023 covered by the requested regulations. This distribution predicted the probabilities of a specific number of strikes (n=0, 1, 2, etc.) over the period from 2018 to 2023. The analysis is described in detail in Chapter 6 of the Navy's rulemaking/LOA application (and further refined in the Navy's revised ship strike analysis posted on NMFS' website https://www.fisheries.noaa.gov/​national/​marine-mammal-protection/​incidental-take-authorizations-military-readiness-activities).

For the same reasons listed above describing why a Navy vessel strike is comparatively unlikely, it is highly unlikely that a Navy vessel would strike a whale, dolphin, porpoise, or pinniped without detecting it and, accordingly, NMFS is confident that the Navy's reported strikes are accurate and appropriate for use in the analysis. Specifically, Navy ships have multiple Lookouts, including on the forward part of the ship that can visually detect a hit animal, in the unlikely event ship personnel do not feel the strike (which has occasionally occurred). Navy's strict internal procedures and mitigation requirements include reporting of any vessel strikes of marine mammals, and the Navy's discipline, extensive training (not only for detecting marine mammals, but for detecting and reporting any potential navigational obstruction), and strict chain of command give NMFS a high level of confidence that all strikes actually get reported.

The Navy used those two fin whale strikes in their calculations to determine the number of strikes likely to result from their activities (although worldwide strike information, from all Navy activities and other strikes, was used to inform the species that may be struck) and evaluated data beginning in 2009, as that was the start of the Navy's Marine Species Awareness Training and adoption of additional mitigation measures to address ship strike, which will remain in place along with additional mitigation measures during the five years of this rule.

The probability analysis concluded that there was a 29 percent chance that zero whales would be struck by Navy vessels over the five-year period, indicating a 71 percent chance that at least one whale would be struck over the five years and a 10 percent chance of striking three whales over the five-year period. Therefore, the Navy estimates, and NMFS agrees, that there is some probability that the Navy could strike, and take by serious injury or mortality, up to three large whales incidental to training and testing activities within the HSTT Study Area over the course of the five years.

Small delphinids, porpoises, and pinnipeds are neither expected nor authorized to be struck by Navy vessels. In addition to the reasons listed above that make it unlikely that the Navy will hit a large whale (more maneuverable ships, larger crew, etc.), following are the additional reasons that vessel strike of dolphins, small whales, porpoises, and pinnipeds is considered very unlikely. Dating back more than 20 years and for as long as it has kept records, the Navy has no records of individuals of these groups being struck by a vessel as a result of Navy activities Start Printed Page 66944and, further, their smaller size and maneuverability make a strike unlikely. Also, NMFS has never received any reports from other authorized activities indicating that these species have been struck by vessels. Worldwide ship strike records show little evidence of strikes of these groups from the shipping sector and larger vessels and the majority of the Navy's activities involving faster-moving vessels (that could be considered more likely to hit a marine mammal) are located in offshore areas where smaller delphinid, porpoise, and pinniped densities are lower. Based on this information, NMFS concurs with the Navy's assessment and recognizes the potential for (and is authorizing) incidental take by vessel strike of large whales only (i.e., no dolphins, small whales, porpoises, or pinnipeds) over the course of the five-year regulations from training and testing activities as discussed below.

For large whales, the Navy's application identified the distribution of species over which the take request would apply based on the species/stocks most likely to be present in the HSTT Study Area based on documented abundance and where overlap occurs between a species' distribution and core Navy training and testing areas within the HSTT Study Area. To determine which species may be struck, the Navy used a weight of evidence approach to qualitatively rank range complex specific species using historic and current stranding data from NMFS, relative abundance as derived by NMFS for the HSTT Biological Opinion, and the Navy-funded monitoring data within each range complex. Results of this approach are presented in Table 5-4 of the Navy's rulemaking/LOA application.

Based on the analysis described above and in its application, the Navy estimated that it has the potential to strike, and take by serious injury or mortality, up to three large whales incidental to the specified activity over the course of the five years of the HSTT regulations. The Navy initially requested incidental take authorization for up to two of any the following stocks in the five-year period: gray whale (Eastern North Pacific stock), fin whale (CA/OR/WA stock), humpback whale (CA/OR/WA stock, Mexico DPS), humpback whale (Central North Pacific stock), and sperm whale (Hawaii stock). The Navy also initially requested incidental take authorization for one of any the following species over the five-year period: blue whale (Eastern North Pacific stock), Bryde's whale (Eastern Tropical Pacific stock), Bryde's whale (Hawaii stock), humpback whale (CA/OR/WA stock, Central America DPS), minke whale (CA/OR/WA stock), minke whale (Hawaii stock), sperm whale (CA/OR/WA stock), sei whale (Hawaii stock), and sei whale (Eastern North Pacific stock).

NMFS independently reviewed this analysis and agrees that three ship strikes have at least the potential to occur and, therefore, that the request for mortal takes of three large whales over the five-year period of the rule is reasonable based on the available strike data (two strikes by Navy over approximately 10 years) and the Navy's probability analysis. Based on the reasons described below, however, NMFS does not agree that two mortal takes of humpback whale (CA/OR/WA stock) or sperm whales are likely, or that any strike of the following whale species is remotely likely: Minke whale (CA/OR/WA stock), minke whale (Hawaii stock), sei whale (Hawaii stock), sei whale (Eastern North Pacific stock), Bryde's whale (Eastern Tropical Pacific stock), sperm whale (CA/OR/WA stock) and Bryde's whale (Hawaii stock).

Since the proposed rule was published, NMFS and the Navy re-examined and re-analyzed the available information regarding how many of any given stock could be struck and should be authorized for lethal take. As noted in the proposed rule, the Navy initially considered a weight of evidence approach that considered relative abundance, historical strike data over many years, and the overlap of Navy activities with the stock distribution in their request. Since the proposed rule, NMFS and the Navy further discussed the available information and considered two factors in addition to those considered in the Navy's additional request: (1) The relative likelihood of hitting one stock versus another based on available strike data from all vessel types as denoted in the SARs and (2) whether the Navy has ever definitively struck an individual from a particular stock and, if so, how many times.

To address number (1) above, NMFS compiled information from NMFS' SARs on detected annual rates of large whale serious injury and mortality from vessel collisions. The annual rates of large whale serious injury and mortality from vessel collisions from the SARs help inform the relative susceptibility of large whale species to vessel strike in SOCAL and Hawaii as recorded systematically over the last five years. We summed the annual rates of mortality and serious injury from vessel collisions as reported in the SARs, then divided each species' annual rate by this sum to get the relative likelihood. To estimate the percent likelihood of striking a particular species of large whale, we multiplied the relative likelihood of striking each species by the total probability of striking a whale (i.e., 71 percent, as described by the Navy's probability analysis above). We also calculated the percent likelihood of striking a particular species of large whale twice by squaring the value estimated for the probability of striking a particular species of whale once (i.e., to calculate the probability of an event occurring twice, multiply the probability of the first event by the second). We note that these probabilities vary from year to year as the average annual mortality for a given five-year window changes (and we include the annual averages from 2017 and 2018 SARs in Table 43 to illustrate), however, over the years and through changing SARs, stocks tend to consistently maintain a relatively higher or relatively lower likelihood of being struck.

The probabilities calculated as described above are then considered in combination with the information indicating the species that the Navy has definitively hit in the HSTT Study Area since 1991 (since they started tracking consistently), as well as the information originally considered by the Navy in their application, which includes relative abundance, total recorded strikes, and the overlay of all of this information with the Navy's action area. We note that for all of the mortal take of species specifically denoted in Table 43 below, 19 percent of the individuals struck overall by any vessel type remained unidentified and 36 percent of those struck by the Navy (5 of 14 in the Pacific) remained unidentified. However, given the information on known stocks struck, the analysis below remains appropriate. We also note that Rockwood et al. (2017) modeled the likely vessel strike of blue whales, fin whales, and humpback whales on the U.S. West Coast (discussed in more detail in the Serious Injury and Mortality subsection of the Analysis and Negligible Impact Determination section), and those numbers help inform the relative likelihood that the Navy will hit those stocks.

For each indicated stock, Table 43 includes the percent likelihood of hitting an individual whale once based on SAR data, total strikes from Navy vessels and from all other vessels, relative abundance, and modeled vessel strikes from Rockwood et al. The last column indicates the annual mortality authorized: those stocks with one M/SI take authorized over the five-year period of the rule are shaded lightly, while those with two M/SI takes authorized Start Printed Page 66945over the five-year period of the rule are shaded more darkly.

Accordingly, stocks that have no record of ever having been struck by any vessel are considered unlikely to be struck by the Navy in the five-year period of the rule. Stocks that have never been struck by the Navy, have rarely been struck by other vessels, and have a low percent likelihood based on the SAR calculation and a low relative abundance are also considered unlikely to be struck by the Navy during the five-year rule. We note that while vessel strike records have not differentiated between Eastern North Pacific and Western North Pacific gray whales, given their small population size and the comparative rarity with which individuals from the Western North Pacific stock are detected off the U.S. West Coast, it is highly unlikely that they would be encountered, much less struck. This rules out all but six stocks.

Three of the six stocks (CA/OR/WA stock of fin whale, Eastern North Pacific stock of gray whale, and Central North Pacific stock of humpback whale) are the only stocks to have been hit more than one time each by the Navy in the HSTT StudyAarea, have the three highest total strike records (21, 35, and 58 respectively), have three of the four highest percent likelihoods based on the SAR records, have three of the four significantly higher relative abundances, and have up to a 3 or 4 percent likelihood of being struck twice based on NMFS' SAR calculation (not shown in Table 43, but proportional to percent likelihood of being struck once). Based on all of these factors, it is considered reasonably likely that these stocks could be struck twice during the five-year rule.

Based on the information summarized in Table 43 and the fact that we expect three large whales could be struck, it is considered reasonably likely that one individual from the remaining three stocks could be struck. Sperm whales have only been struck a total of two times by any vessel type in the whole HSTT Study Area, however, the Navy struck a sperm whale once in Hawaii prior to 2009 and the relative abundance of sperm whales in Hawaii is the highest of any of the stocks present. Therefore, we consider it reasonably likely that the Hawaii stock of sperm whales could be struck once during the five-year rule. The total strikes of Eastern North Pacific blue whales, the percent likelihood of striking one based on the SAR calculation, and their relative abundance can all be considered moderate compared to other stocks and the Navy has struck one in the past prior to 2009 (with the likelihood of striking two based on the SAR calculation being below one percent). Therefore, we consider it reasonably likely that the Navy could strike one individual over the course of the five-year rule. The Navy has not hit a humpback whale in the HSTT Study Area and their relative abundance is very low. However, the Navy has struck a humpback whale in the Northwest and as a species, humpbacks have a moderate to high number of total strikes and percent likelihood of being struck. Although the likelihood of CA/OR/WA humpback whales being struck overall is moderate to high relative to other stocks, the distribution of the Mexico DPS versus the Central America DPS, as well as the distribution of overall vessel strikes inside versus outside of the SOCAL area (the majority are outside), supports the reasonable likelihood that the Navy could strike one individual humpback whale (not two), and that that Start Printed Page 66946individual would be highly likely to be from the Mexico DPS, as described below.

Specifically, regarding the likelihood of striking a humpback whale from a particular DPS, as suggested in Wade et al. (2016), the probability of encountering (which is thereby applied to striking) humpback whales from each DPS in the CA/OR area is 89.6 percent and 19.7 percent for the Mexico and Central America DPSs, respectively (note that these percentages reflect the upper limit of the 95 percent confidence interval to reduce the likelihood of underestimating take, and thereby do not total to 100). This suggests that the chance of striking a whale from the Central America DPS is one tenth to one fifth of the overall chance of hitting a CA/OR/WA humpback whale in general in the SOCAL part of the HSTT Study Area, which in combination with the fact that no humpback whale has been struck in SOCAL makes it highly unlikely, and thereby none from the Central America DPS are anticipated or authorized. If a humpback whale were struck in SOCAL, it is likely it would be of the Mexico DPS. However, regarding the overall likelihood of striking a humpback whale at all and the likely number of times, we note that the majority of strikes of the CA/OR/WA humpback whale (i.e., the numbers reflected in Table 43) take place outside of SOCAL and, whereas the comparative DPS numbers cited above apply in the California and Oregon feeding area, in the Washington and Southern British Columbia feeding area, Wade et al. (2016) suggest that 52.9, 41.9, and 14.7 percent of humpback whales encountered will come from the Hawaii, Mexico, and Central America DPSs, respectively. This means that the numbers in Table 43 indicating the overall strikes of CA/OR/WA humpback whales and SAR calculations based on average annual mortality over the last five years are actually lower than indicated for the Mexico DPS, which would only be a subset of those mortalities. Last, the Rockwood et al. paper supports a relative likelihood of 1:1:2 for striking blue whales, humpback whales, and fin whales off the U.S. West Coast, which supports the authorized take included in this rule, which is 1, 1, and 2, respectively over the five-year period. For these reasons, one mortal take of CA/OR/WA humpback whales, which would be expected to be of the Mexico DPS, could reasonably likely occur and is authorized.

Accordingly, the Navy revised their request for take by serious injury or mortality to include up to two of any the following species in the five-year period: Gray whale (Eastern North Pacific stock), fin whale (CA/OR/WA stock), humpback whale (Central North Pacific stock); and one of any of the following species in the five year period: Blue whale (Eastern North Pacific stock), humpback whale (CA/OR/WA stock, Mexico DPS), or sperm whale (Hawaii stock).

As described above, NMFS and the Navy concur that vessel strikes to the stocks below are very unlikely to occur due to the stocks' relatively low occurrence in the HSTT Study Area, particularly in core HSTT training and testing subareas, and the fact that the stocks have not been struck by the Navy and are rarely, if ever, recorded struck by other vessels. Therefore the Navy is not requesting lethal take authorization, and NMFS is not authorizing lethal take, for the following stocks: Bryde's whale (Eastern Tropical Pacific stock), Bryde's whale (Hawaii stock), humpback whale (CA/OR/WA stock, Central America DPS), minke whale (CA/OR/WA stock), minke whale (Hawaii stock), sei whale (Hawaii stock), sei whale (Eastern North Pacific stock), and sperm whale (CA/OR/WA stock).

In conclusion, although it is generally unlikely that any whales will be struck in a year, based on the information and analysis above, NMFS anticipates that no more than three whales could be taken by serious injury or mortality over the five-year period of the rule, and that those three whales may include no more than two of any of the following stocks: Gray whale (Eastern North Pacific stock), fin whale (CA/OR/WA stock), humpback whale (Central North Pacific stock); and no more than one of any of the following stocks: Blue whale (Eastern North Pacific stock), humpback whale (CA/OR/WA, Mexico DPS), and sperm whale (Hawaii stock). Accordingly, NMFS has evaluated under the negligible impact standard the serious injury or mortality of 0.2 or 0.4 whales annually from each of these species or stocks (i.e., 1 or 2 takes, respectively, divided by 5 years to get the annual number), along with other expected harassment incidental take.

Explosives

The Navy's model and quantitative analysis process used for the HSTT FEIS/OEIS and in the Navy's rulemaking/LOA application to estimate potential exposures of marine mammals to explosive stressors is detailed in the technical report titled Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing report (U.S. Department of the Navy, 2018). Specifically, over the course of a year, the Navy's model and quantitative analysis process estimates mortality of two short-beaked common dolphin and one California sea lion as a result of exposure to explosive training and testing activities (please refer to section 6 of the Navy's rule making/LOA application). Over the five‐year period of the regulations requested, mortality of 10 marine mammals in total (6 short-beaked common dolphins and 4 California sea lions) is estimated as a result of exposure to explosive training and testing activities. NMFS coordinated with the Navy in the development of their take estimates and concurs with the Navy's approach for estimating the number of animals from each species that could be affected by mortality takes from explosives.

Mitigation Measures

Under section 101(a)(5)(A) of the MMPA, NMFS must set forth the “permissible methods of taking pursuant to such activity, and other means of effecting the least practicable adverse impact on such species or stock and its habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance, and on the availability of such species or stock for subsistence uses” (“least practicable adverse impact”). NMFS does not have a regulatory definition for least practicable adverse impact. The NDAA for FY 2004 amended the MMPA as it relates to military readiness activities and the incidental take authorization process such that a determination of “least practicable adverse impact” shall include consideration of personnel safety, practicality of implementation, and impact on the effectiveness of the military readiness activity.

In Conservation Council for Hawaii v. National Marine Fisheries Service, 97 F. Supp.3d 1210, 1229 (D. Haw. 2015), the Court stated that NMFS “appear[s] to think [it] satisfies] the statutory `least practicable adverse impact' requirement with a `negligible impact' finding.” More recently, expressing similar concerns in a challenge to a U.S. Navy Surveillance Towed Array Sensor System Low Frequency Active Sonar (SURTASS LFA) incidental take rule (77 FR 50290), the Ninth Circuit Court of Appeals in Natural Resources Defense Council (NRDC) v. Pritzker, 828 F.3d 1125, 1134 (9th Cir. 2016), stated, “[c]ompliance with the `negligible impact' requirement does not mean there [is] compliance with the `least practicable adverse impact' standard.” As the Ninth Circuit noted in its opinion, however, the Court was Start Printed Page 66947interpreting the statute without the benefit of NMFS' formal interpretation. We state here explicitly that NMFS is in full agreement that the “negligible impact” and “least practicable adverse impact” requirements are distinct, even though both statutory standards refer to species and stocks. With that in mind, we provide further explanation of our interpretation of least practicable adverse impact, and explain what distinguishes it from the negligible impact standard. This discussion is consistent with, and expands upon, previous rules we have issued, such as the Navy Gulf of Alaska rule (82 FR 19530; April 27, 2017) and the Navy Atlantic Fleet Testing and Training rule (83 FR 57076; November 14, 2018).

Before NMFS can issue incidental take regulations under section 101(a)(5)(A) of the MMPA, it must make a finding that the total taking will have a “negligible impact” on the affected “species or stocks” of marine mammals. NMFS' and U.S. Fish and Wildlife Service's implementing regulations for section 101(a)(5) both define “negligible impact” as “an impact resulting from the specified activity that cannot be reasonably expected to, and is not reasonably likely to, adversely affect the species or stock through effects on annual rates of recruitment or survival” (50 CFR 216.103 and 50 CFR 18.27(c)). Recruitment (i.e., reproduction) and survival rates are used to determine population growth rates [3] and, therefore are considered in evaluating population level impacts.

As we stated in the preamble to the final rule for the incidental take implementing regulations, not every population-level impact violates the negligible impact requirement. The negligible impact standard does not require a finding that the anticipated take will have “no effect” on population numbers or growth rates: “The statutory standard does not require that the same recovery rate be maintained, rather that no significant effect on annual rates of recruitment or survival occurs. [T]he key factor is the significance of the level of impact on rates of recruitment or survival.” (54 FR 40338, 40341-42; September 29, 1989).

While some level of impact on population numbers or growth rates of a species or stock may occur and still satisfy the negligible impact requirement—even without consideration of mitigation—the least practicable adverse impact provision separately requires NMFS to prescribe means of “effecting the least practicable adverse impact on such species or stock and its habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance,” 50 CFR 216.102(b), which are typically identified as mitigation measures.[4]

The negligible impact and least practicable adverse impact standards in the MMPA both call for evaluation at the level of the “species or stock.” The MMPA does not define the term “species.” However, Merriam-Webster Dictionary defines “species” to include “related organisms or populations potentially capable of interbreeding.” See www.merriam-webster.com/​dictionary/​species (emphasis added). The MMPA defines “stock” as a group of marine mammals of the same species or smaller taxa in a common spatial arrangement that interbreed when mature (16 U.S.C. 1362(11)). The definition of “population” is a group of interbreeding organisms that represents the level of organization at which speciation begins. www.merriam-webster.com/​dictionary/​population. The definition of “population” is strikingly similar to the MMPA's definition of “stock,” with both involving groups of individuals that belong to the same species and located in a manner that allows for interbreeding. In fact, the term “stock” in the MMPA is interchangeable with the statutory term “population stock.” 16 U.S.C. 1362(11). Both the negligible impact standard and the least practicable adverse impact standard call for evaluation at the level of the species or stock, and the terms “species” and “stock” both relate to populations; therefore, it is appropriate to view both the negligible impact standard and the least practicable adverse impact standard as having a population-level focus.

This interpretation is consistent with Congress's statutory findings for enacting the MMPA, nearly all of which are most applicable at the species or stock (i.e., population) level. See 16 U.S.C. 1361 (finding that it is species and population stocks that are or may be in danger of extinction or depletion; that it is species and population stocks that should not diminish beyond being significant functioning elements of their ecosystems; and that it is species and population stocks that should not be permitted to diminish below their optimum sustainable population level). Annual rates of recruitment (i.e., reproduction) and survival are the key biological metrics used in the evaluation of population-level impacts, and accordingly these same metrics are also used in the evaluation of population level impacts for the least practicable adverse impact standard.

Recognizing this common focus of the least practicable adverse impact and negligible impact provisions on the “species or stock” does not mean we conflate the two standards; despite some common statutory language, we recognize the two provisions are different and have different functions. First, a negligible impact finding is required before NMFS can issue an incidental take authorization. Although it is acceptable to use the mitigation measures to reach a negligible impact finding (see 50 CFR 216.104(c)), no amount of mitigation can enable NMFS to issue an incidental take authorization for an activity that still would not meet the negligible impact standard. Moreover, even where NMFS can reach a negligible impact finding—which we emphasize does allow for the possibility of some “negligible” population-level impact—the agency must still prescribe measures that will affect the least practicable amount of adverse impact upon the affected species or stock.

Section 101(a)(5)(A)(i)(II) requires NMFS to issue, in conjunction with its authorization, binding—and enforceable—restrictions (in the form of regulations) setting forth how the activity must be conducted, thus ensuring the activity has the “least practicable adverse impact” on the affected species or stocks and their habitat. In situations where mitigation is specifically needed to reach a negligible impact determination, section 101(a)(5)(A)(i)(II) also provides a mechanism for ensuring compliance with the “negligible impact” requirement. Finally, we reiterate that the least practicable adverse impact standard also requires consideration of measures for marine mammal habitat, with particular attention to rookeries, mating grounds, and other areas of similar significance, and for subsistence impacts, whereas the negligible impact standard is concerned solely with conclusions about the impact of an activity on annual rates of recruitment and survival.[5]

In NRDC v. Pritzker, the Court stated, “[t]he statute is properly read to mean that even if population levels are not threatened significantly, still the agency must adopt mitigation measures aimed at protecting marine mammals to the greatest extent practicable in light of Start Printed Page 66948military readiness needs.” Id. at 1134 (emphases added). This statement is consistent with our understanding stated above that even when the effects of an action satisfy the negligible impact standard (i.e., in the Court's words, “population levels are not threatened significantly”), still the agency must prescribe mitigation under the least practicable adverse impact standard. However, as the statute indicates, the focus of both standards is ultimately the impact on the affected “species or stock,” and not solely focused on or directed at the impact on individual marine mammals.

We have carefully reviewed and considered the Ninth Circuit's opinion in NRDC v. Pritzker in its entirety. While the Court's reference to “marine mammals” rather than “marine mammal species or stocks” in the italicized language above might be construed as a holding that the least practicable adverse impact standard applies at the individual “marine mammal” level, i.e., that NMFS must require mitigation to minimize impacts to each individual marine mammal unless impracticable, we believe such an interpretation reflects an incomplete appreciation of the Court's holding. In our view, the opinion as a whole turned on the Court's determination that NMFS had not given separate and independent meaning to the least practicable adverse impact standard apart from the negligible impact standard, and further, that the Court's use of the term “marine mammals” was not addressing the question of whether the standard applies to individual animals as opposed to the species or stock as a whole. We recognize that while consideration of mitigation can play a role in a negligible impact determination, consideration of mitigation measures extends beyond that analysis. In evaluating what mitigation measures are appropriate, NMFS considers the potential impacts of the specified activities, the availability of measures to minimize those potential impacts, and the practicability of implementing those measures, as we describe below.

Implementation of Least Practicable Adverse Impact Standard

Given the NRDC v. Pritzker decision, we discuss here how we determine whether a measure or set of measures meets the “least practicable adverse impact” standard. Our separate analysis of whether the take anticipated to result from Navy's activities meets the “negligible impact” standard appears in the Analysis and Negligible Impact Determination section below.

Our evaluation of potential mitigation measures includes consideration of two primary factors:

(1) The manner in which, and the degree to which, implementation of the potential measure(s) is expected to reduce adverse impacts to marine mammal species or stocks, their habitat, and their availability for subsistence uses (where relevant). This analysis considers such things as the nature of the potential adverse impact (such as likelihood, scope, and range), the likelihood that the measure will be effective if implemented, and the likelihood of successful implementation; and

(2) The practicability of the measures for applicant implementation. Practicability of implementation may consider such things as cost, impact on activities, and, in the case of a military readiness activity, specifically considers personnel safety, practicality of implementation, and impact on the effectiveness of the military readiness activity. 16 U.S.C. 1371(a)(5)(A)(iii).

While the language of the least practicable adverse impact standard calls for minimizing impacts to affected species or stocks and their habitats, we recognize that the reduction of impacts to those species or stocks accrues through the application of mitigation measures that limit impacts to individual animals. Accordingly, NMFS' analysis focuses on measures that are designed to avoid or minimize impacts on individual marine mammals that are likely to increase the probability or severity of population-level effects.

While direct evidence of impacts to species or stocks from a specified activity is rarely available, and additional study is still needed to understand how specific disturbance events affect the fitness of individuals of certain species, there have been improvements in understanding the process by which disturbance effects are translated to the population. With recent scientific advancements (both marine mammal energetic research and the development of energetic frameworks), the relative likelihood or degree of impacts on species or stocks may often be inferred given a detailed understanding of the activity, the environment, and the affected species or stocks. This same information is used in the development of mitigation measures and helps us understand how mitigation measures contribute to lessening effects (or the risk thereof) to species or stocks. We also acknowledge that there is always the potential that new information, or a new recommendation that we had not previously considered, becomes available and necessitates reevaluation of mitigation measures (which may be addressed through adaptive management) to see if further reductions of population impacts are possible and practicable.

In the evaluation of specific measures, the details of the specified activity will necessarily inform each of the two primary factors discussed above (expected reduction of impacts and practicability), and are carefully considered to determine the types of mitigation that are appropriate under the least practicable adverse impact standard. Analysis of how a potential mitigation measure may reduce adverse impacts on a marine mammal stock or species, consideration of personnel safety, practicality of implementation, and consideration of the impact on effectiveness of military readiness activities are not issues that can be meaningfully evaluated through a yes/no lens. The manner in which, and the degree to which, implementation of a measure is expected to reduce impacts, as well as its practicability in terms of these considerations, can vary widely. For example, a time/area restriction could be of very high value for decreasing population-level impacts (e.g., avoiding disturbance of feeding females in an area of established biological importance) or it could be of lower value (e.g., decreased disturbance in an area of high productivity but of less firmly established biological importance). Regarding practicability, a measure might involve restrictions in an area or time that impede the Navy's ability to certify a strike group (higher impact on mission effectiveness), or it could mean delaying a small in-port training event by 30 minutes to avoid exposure of a marine mammal to injurious levels of sound (lower impact). A responsible evaluation of “least practicable adverse impact” will consider the factors along these realistic scales. Accordingly, the greater the likelihood that a measure will contribute to reducing the probability or severity of adverse impacts to the species or stock or their habitat, the greater the weight that measure is given when considered in combination with practicability to determine the appropriateness of the mitigation measure, and vice versa. In the evaluation of specific measures, the details of the specified activity will necessarily inform each of the two primary factors discussed above (expected reduction of impacts and practicability), and will be carefully considered to determine the types of mitigation that are appropriate under the least practicable adverse impact Start Printed Page 66949standard. We discuss consideration of these factors in greater detail below.

1. Reduction of adverse impacts to marine mammal species or stocks and their habitat.[6] The emphasis given to a measure's ability to reduce the impacts on a species or stock considers the degree, likelihood, and context of the anticipated reduction of impacts to individuals (and how many individuals) as well as the status of the species or stock.

The ultimate impact on any individual from a disturbance event (which informs the likelihood of adverse species- or stock-level effects) is dependent on the circumstances and associated contextual factors, such as duration of exposure to stressors. Though any proposed mitigation needs to be evaluated in the context of the specific activity and the species or stocks affected, measures with the following types of effects have greater value in reducing the likelihood or severity of adverse species- or stock-level impacts: Avoiding or minimizing injury or mortality; limiting interruption of known feeding, breeding, mother/young, or resting behaviors; minimizing the abandonment of important habitat (temporally and spatially); minimizing the number of individuals subjected to these types of disruptions; and limiting degradation of habitat. Mitigating these types of effects is intended to reduce the likelihood that the activity will result in energetic or other types of impacts that are more likely to result in reduced reproductive success or survivorship. It is also important to consider the degree of impacts that are expected in the absence of mitigation in order to assess the added value of any potential measures. Finally, because the least practicable adverse impact standard gives NMFS discretion to weigh a variety of factors when determining appropriate mitigation measures and because the focus of the standard is on reducing impacts at the species or stock level, the least practicable adverse impact standard does not compel mitigation for every kind of take, or every individual taken, if that mitigation is unlikely to meaningfully contribute to the reduction of adverse impacts on the species or stock and its habitat, even when practicable for implementation by the applicant.

The status of the species or stock is also relevant in evaluating the appropriateness of potential mitigation measures in the context of least practicable adverse impact. The following are examples of factors that may (either alone, or in combination) result in greater emphasis on the importance of a mitigation measure in reducing impacts on a species or stock: The stock is known to be decreasing or status is unknown, but believed to be declining; the known annual mortality (from any source) is approaching or exceeding the potential biological removal (PBR) level (as defined in 16 U.S.C. 1362(20)); the affected species or stock is a small, resident population; or the stock is involved in a UME or has other known vulnerabilities, such as recovering from an oil spill.

Habitat mitigation, particularly as it relates to rookeries, mating grounds, and areas of similar significance, is also relevant to achieving the standard and can include measures such as reducing impacts of the activity on known prey utilized in the activity area or reducing impacts on physical habitat. As with species- or stock-related mitigation, the emphasis given to a measure's ability to reduce impacts on a species or stock's habitat considers the degree, likelihood, and context of the anticipated reduction of impacts to habitat. Because habitat value is informed by marine mammal presence and use, in some cases there may be overlap in measures for the species or stock and for use of habitat.

We consider available information indicating the likelihood of any measure to accomplish its objective. If evidence shows that a measure has not typically been effective nor successful, then either that measure should be modified or the potential value of the measure to reduce effects should be lowered.

2. Practicability. Factors considered may include cost, impact on activities, and, in the case of a military readiness activity, personnel safety, practicality of implementation, and impact on the effectiveness of the military readiness activity (16 U.S.C. 1371(a)(5)(A)(iii)).

Assessment of Mitigation Measures for HSTT Rule

NMFS reviewed the Specified Activities and the mitigation measures as described in the Navy's rulemaking/LOA application and the HSTT FEIS/OEIS to determine if they would result in the least practicable adverse effect on marine mammals. NMFS worked with the Navy in the development of the Navy's initially proposed measures, which are informed by years of implementation and monitoring. A complete discussion of the evaluation process used to develop, assess, and select mitigation measures, which was coordinated with and informed by input from NMFS and included consideration of the measures that were added as a result of the settlement agreement (see below), can be found in Chapter 5 (Mitigation) and Appendix K (Geographic Mitigation Assessment) of the HSTT FEIS/OEIS and is summarized below in this section. The process described in Chapter 5 (Mitigation) and Appendix K (Geographic Mitigation Assessment) of the HSTT FEIS/OEIS robustly supports NMFS' independent evaluation of whether the mitigation measures required by this rule meet the least practicable adverse impact standard. The Navy is required to implement the mitigation measures identified in this rule to avoid or reduce potential impacts from acoustic, explosive, and physical disturbance and ship strike stressors.

As a general matter, where an applicant proposes measures that are likely to reduce impacts to marine mammals, the fact that they are included in the proposal and application indicates that the measures are practicable, and it is not necessary for NMFS to conduct a detailed analysis of the measures the applicant proposed (rather, they are simply included). We note that in their application, the Navy added a couple of mitigation measures that were new since the 2013-2018 HSTT incidental take regulations: (1) The Santa Barbara Island Mitigation Area—to avoid or reduce potential impacts from mid-frequency active sonar and explosives on numerous marine mammal species (including blue whales and gray whales) within the mitigation area, which contains important foraging or migration habitat and overlaps a portion of the Channel Islands National Marine Sanctuary, and (2) Blue Whale, Gray Whale, and Fin Whale Awareness Notification Message Areas—to further help avoid or reduce potential impacts from vessel strikes and training and testing activities on blue whales, gray whales, and fin whales within the Southern California portion of the Study Area, which contains important seasonal foraging or migration habitat for these species. However, it is still necessary for NMFS to consider whether there are additional practicable measures that could also contribute to the reduction of adverse effects on the species or stocks through effects on annual rates of recruitment or survival. In the case of the Navy's HSTT application, we worked with the Navy Start Printed Page 66950prior to the publication of the proposed rule and ultimately, the Navy agreed to significantly expand geographic mitigation areas adjacent to the island of Hawaii to more fully encompass the Alenuihaha Channel (important habitat and migration area) and overlap the BIAs of multiple species (reproductive area for humpbacks, and overlapping the ranges of multiple small resident populations of odontocetes) and to limit additional anti-submarine warfare mid-frequency active sonar (ASW) source bins (MF4) within those mitigation areas, which is expected to further reduce the probability and severity of impacts that would be more likely to affect reproduction or survival of individuals or adversely affect the stock.

Of note, following publication of the 2013 HSTT incidental take rule, the Navy and NMFS were sued and the parties reached a settlement in Conservation Council for Hawaii v. National Marine Fisheries Service, 97 F. Supp.3d 1210 (D. Haw. 2015), in which the Navy agreed to restrict its activities within specific areas in the HSTT Study Area (beyond the areas and restrictions included as mitigation measures in the 2013 rule). Additional detail is provided below in the subsection entitled Brief Comparison of Settlement Mitigation and Final HSTT Mitigation in the Rule.

In summary (and as described in more detail below in this section), the Navy has agreed to procedural mitigation measures that will reduce the probability and/or severity of impacts expected to result from acute exposure to acoustic sources or explosives, ship strike, and impacts to marine mammal habitat. Specifically, the Navy will use a combination of delayed starts, powerdowns, and shutdowns to minimize or avoid serious injury or mortality, minimize the likelihood or severity of PTS or other injury, and reduce instances of TTS or more severe behavioral disruption caused by acoustic sources or explosives. The Navy also will implement multiple time/area restrictions (several of which have been added since the 2013 HSTT MMPA incidental take rule) that would reduce take of marine mammals in areas or at times where they are known to engage in important behaviors, such as feeding or calving, where the disruption of those behaviors would have a higher probability of resulting in impacts on reproduction or survival of individuals that could lead to population-level impacts.

Since publication of the proposed rule, NMFS and the Navy have agreed to additional mitigation measures that are expected to reduce the likelihood and/or severity of adverse impacts on marine species/stocks and their habitat and are practicable for implementation. Below we summarize the added measures and describe the manner in which they are expected to reduce the likelihood or severity of adverse impacts on marine mammal species or stocks and their habitat. A full description of each measure is included in Tables 45-62.

1. Pre-event in-water explosive event observations—The Navy will implement pre-event observation mitigation for all in-water explosive event mitigation measures. Additionally, if there are other platforms participating in these events and in the vicinity of the detonation area, Navy personnel on those platforms will also visually observe this area as part of the mitigation team. This added monitoring for a subset of activities for which it was not previously required (explosive bombs, missiles and rockets, projectiles, torpedoes, and grenades) in advance of explosive events increases the likelihood that marine mammals will be detected if they are in the mitigation area for that event and that, if any animals are detected, explosions will be delayed by timely mitigation implementation, thereby further reducing the already low likelihood that animals will be injured or killed by the blast.

2. Post-event in-water explosive event observations—The Navy will implement post-event observation mitigation for all in-water explosive event mitigation measures. Additionally, if there are other platforms participating in these events and in the vicinity of the detonation area, Navy personnel on those platforms will also visually observe this area as part of the mitigation team. This added monitoring for a subset of activities for which it was not previously required (explosive bombs, missiles and rockets, projectiles, torpedoes, grenades) increases the likelihood that any injured marine mammals would be detected following an explosive event, which would increase our understanding of impacts and could potentially inform mitigation changes via the adaptive management provisions.

3. The San Diego Arc Mitigation Area was the initial mitigation area for the proposed rule. For the final rule, the Navy agreed to add the San Nicolas Island and Santa Monica/Long Beach Mitigation Areas (June 1-October 31), which include all of the relatively small portions of the Santa Monica Bay/Long Beach and San Nicolas Island BIAs that overlap the HSTT Study Area (55.4 Nmi2 or 13.9 percent and 33.6 Nmi2 or 23.5 percent, respectively). The Navy agrees to limit explosives during training in the Santa Monica Bay/Long Beach and San Nicolas Island Mitigation Areas. This reduction of activities (as described here and in the newly expanded measure immediately below, i.e., fewer explosives and MF1 sonar) in these areas with higher concentrations of blue whales engaged in important feeding behaviors is expected to reduce the probability or severity of impacts on blue whales that would be more likely to adversely affect the reproduction or survival of any individual, which in turn reduces the likelihood that any impacts would translate to adverse impacts on the stock.

4. The Navy agrees to limit surface ship sonar in the Santa Monica/Long Beach and San Nicolas Island Mitigation Areas. The Navy will not exceed 200 hrs of MFAS sensor MF1 from June 1 through October 31 in the combined San Diego Arc, San Nicolas Island, and Santa Monica/Long Beach Mitigation Areas (manner in which this helps reduce impact to marine mammals noted directly above).

5. In the proposed rule, the Navy included a seasonal restriction on the use of hull-mounted active sonar in the 4-Islands Mitigation Area, but no limit on explosive use. The Navy has added an all-year restriction on the use of explosives in this area. The 4-Islands Mitigation Area overlaps with a reproductive BIA for humpback whales, as well as BIAs for several small resident populations of multiple odontocetes (bottlenose dolphins, main Hawaiian Island false killer whales, pantropical spotted dolphins, and spinner dolphins). For humpback whales, the reduction of activities in this area with individuals that have calves or are potentially breeding is expected to reduce the probability or severity of impacts that would be more likely to adversely impact reproduction or survival of individuals by directly interfering with breeding behaviors or by separating mothers and calves at a time with calves are more susceptible to predators. For the odontocete stocks with BIAs for small resident populations, we aim to avoid overwhelming small populations (which are more susceptible to certain population effects, such as Allee effects) with large scale impacts, especially when the population is limited to a small area and less able to access alternative habitat. Limiting explosive effects in these mitigation areas that overlap the BIAs further reduces impacts to these stocks, although we note that all four of these odontocete small resident populations span multiple islands, which means that Start Printed Page 66951impacts in any one location are less likely to affect the whole population.

6. The Navy has agreed to issue notification messages to increase operator awareness of the presence of marine mammals. The Navy will review WhaleWatch, a program coordinated by NMFS' West Coast Region as an additional information source to inform the drafting of the annual notification messages for blue, fin, and gray whales in SOCAL.The information will alert vessels to the possible presence of these stocks to maintain safety of navigation and further reduce the potential for a vessel strike. Any expanded mechanisms for detecting large whales, either directly around a vessel or in the wider area to increase vigilance for vessels, further reduce the probability that a whale will be struck.

The Navy assessed the new and/or expanded measures it has agreed to (above) in the context of personnel safety, practicality of implementation, and their impacts on the Navy's ability to meet their Title 10 requirements and found that the measures were supportable. As described above, NMFS has independently evaluated all of the measures the Navy has committed to (including those above added since the proposed rule was published) in the manner described earlier in this section (i.e., in consideration of their ability to reduce adverse impacts on marine mammal species and stocks and their habitat and their practicability for implementation). We have determined that the additional measures will further reduce impacts on the affected marine mammal species and stocks and their habitat beyond the initial measures proposed and, further, be practicable for Navy implementation.

The Navy also evaluated numerous measures in the HSTT FEIS/OEIS that were not included in the Navy's rulemaking/LOA application, and NMFS independently reviewed and concurs with Navy's analysis that their inclusion was not appropriate under the least practicable adverse impact standard based on our assessment. The Navy considered these additional potential mitigation measures in two groups. First, Chapter 5 (Mitigation) of the HSTT FEIS/OEIS, in the Measures Considered but Eliminated section, includes an analysis of an array of different types of mitigation that have been recommended over the years by NGOs or the public, through scoping or public comment on environmental compliance documents. Appendix K (Geographic Mitigation Assessment) of the HSTT FEIS/OEIS includes an in-depth analysis of time/area restrictions that have been recommended over time or previously implemented as a result of litigation. As described in Chapter 5 (Mitigation) of the HSTT FEIS/OEIS, commenters sometimes recommend that the Navy reduce its overall amount of training, reduce explosive use, modify its sound sources, completely replace live training with computer simulation, or include time of day restrictions. Many of these mitigation measures could potentially reduce the number of marine mammals taken, via direct reduction of the activities or amount of sound energy put in the water. However, as the Navy has described in Chapter 5 (Mitigation) of the HSTT FEIS/OEIS, the Navy needs to train and test in the conditions in which it fights—and these types of modifications fundamentally change the activity in a manner that would not support the purpose and need for the training and testing (i.e., are entirely impracticable) and therefore are not considered further. NMFS finds the Navy's explanation for why adoption of these recommendations would unacceptably undermine the purpose of the testing and training persuasive. After independent review, NMFS finds Navy's judgment on the impacts of potential mitigation measures to personnel safety, practicality of implementation, and the undermining of the effectiveness of training and testing persuasive, and for these reasons, NMFS finds that these measures do not meet the least practicable adverse impact standard because they are not practicable.

Second in Chapter 5 (Mitigation) of the HSTT FEIS/OEIS, the Navy evaluated additional potential procedural mitigation measures, including increased mitigation zones, ramp-up measures, additional passive acoustic and visual monitoring, and decreased vessel speeds. Some of these measures have the potential to incrementally reduce take to some degree in certain circumstances, though the degree to which this would occur is typically low or uncertain. However, as described in the Navy's analysis, the measures would have significant direct negative effects on mission effectiveness and are considered impracticable (see Chapter 5 Mitigation of HSTT FEIS/OEIS). NMFS independently reviewed the Navy's evaluation and concurred with this assessment, which supports NMFS' findings that the impracticability of this additional mitigation would greatly outweigh any potential minor reduction in marine mammal impacts that might result; therefore, these additional mitigation measures are not required under the least practicable adverse impact standard.

Last, Appendix K (Geographic Mitigation Assessment) of the HSTT FEIS/OEIS describes a comprehensive method for analyzing potential geographic mitigation that includes consideration of both a biological assessment of how the potential time/area limitation would benefit the species or stock and its habitat (e.g., is a key area of biological importance or would result in avoidance or reduction of impacts) in the context of the stressors of concern in the specific area and an operational assessment of the practicability of implementation (e.g., including an assessment of the specific importance of that area for training, considering proximity to training ranges and emergency landing fields and other issues). The analysis analyzes an extensive list of areas, including areas in which certain Navy activities were limited under the terms of the 2015 HSTT settlement agreement, areas identified by the California Coastal Commission, and areas suggested during scoping. For the areas that were agreed to under the settlement agreement, the Navy notes two important facts that NMFS generally concurs with: (1) The measures were derived pursuant to negotiations with plaintiffs and were specifically not evaluated or selected based on the examination of the best available science that NMFS typically applies to a mitigation assessment and (2) the Navy's adoption of restrictions on its activities as part of a relatively short-term settlement does not mean that those restrictions are practicable to implement over the longer term.

The Navy proposed (and NMFS has incorporated into this rule) several time/area mitigations that were not included in the 2013-2018 HSTT MMPA regulations (as described above). For the areas that are not included in these regulations, though, the analysis in the HSTT FEIS/OEIS (Chapter 5 and Appendix K) shows that on balance, the mitigation was not warranted because the anticipated reduction of adverse impacts on marine mammal species or stocks and their habitat was not sufficient to offset the impracticability of implementation (in some cases potential benefits to marine mammals were limited to non-existent, in others the consequences on mission effectiveness were too great). We note that in regard to the protection of marine mammal habitat, habitat value is informed by marine mammal presence and use and, in some cases, there may be overlap in measures that minimize impacts to the species or stock directly and measures that minimize impacts on Start Printed Page 66952habitat. In this rule, we have identified time-area mitigations based on a combination of factors that include higher densities and observations of specific important behaviors of marine mammals themselves, but also that clearly reflect preferred habitat (e.g., blue whale feeding areas in SOCAL, and in-shore small resident populations of odontocetes around Hawaii). In addition to being delineated based on physical features that drive habitat function (e.g., bathymetric features, among others for some BIAs), the high densities and concentration of certain important behaviors (e.g., feeding) in these particular areas clearly indicate the presence of preferred habitat.

Overall, NMFS has independently reviewed the Navy's mitigation analysis Chapter 5 (Mitigation) and Appendix K (Geographic Mitigation Assessment) of the HSTT FEIS/OEIS as referenced above), which considers the same factors that NMFS considers to satisfy the least practical adverse impact standard, and concurs with the conclusions. Therefore, NMFS is not including the additional measures discussed in the HSTT FEIS/OEIS in these regulations, other than the new measures that were discussed in the proposed rule and those agreed upon after publication of the proposed rule, as described above. Below, we list and describe the mitigation measures (organized into procedural measures and mitigation areas) that NMFS has determined will ensure the least practicable adverse impact on all affected species and stocks and their habitat, including the specific considerations for military readiness activities. However, first, in the section immediately below, we provide a brief summary of the ways in which the mitigation included in this rule compares to the mitigation the Navy implemented during the settlement agreement.

Brief Comparison of 2015 Settlement Mitigation and Final HSTT Mitigation in the Rule

As noted above, following publication of the 2013 HSTT MMPA incidental take rule, the Navy and NMFS were sued and the parties reached a settlement in 2015 under which the Navy agreed to restrict its activities within specific areas in the HSTT Study Area (beyond the areas and restrictions included in the 2013 rule). While we have described above the analysis that supports the selection of mitigation measures included in the final rule (referencing the associated Navy documents, where appropriate), because the Navy has been implementing the settlement agreement measures since 2015, we provide here a summary description of the differences and additional analysis.

First, we note broadly that the provisional restrictions on activities within the HSTT Study Area were derived pursuant to negotiations with the plaintiffs as part of the lawsuit and specifically were not evaluated or selected based on the best available science as would occur through the MMPA rulemaking process or through related analyses conducted under the National Environmental Policy Act (NEPA) or the ESA. The agreement did not constitute a concession by the Navy as to the impacts of Navy activities on marine mammals or any other marine species, the extent to which the measures would reduce impacts, or the practicability of the measures. The Navy's adoption of restrictions on its HSTT testing and training activities as part of the relatively short-term settlement agreement therefore did not mean that those restrictions were supported by the best available science, likely to reduce impacts on marine mammals species or stocks and their habitat, or practicable to implement from a military readiness standpoint over the longer term in the HSTT Study Area. Accordingly, as required by statute, NMFS analyzed the Navy's activities as set forth in its application and including impacts, proposed mitigation, and additional potential mitigation (including the settlement agreement measures) pursuant to the “least practicable adverse impact” standard to determine the appropriate mitigation to include in these regulations. Some of the measures that were included in the 2015 settlement agreement are included in the final rule, while some are not.

As characterized elsewhere in the rule, we look here at the differences in both procedural mitigation measures and mitigation areas. The 2015 settlement agreement included two procedural mitigations (one of which was a group of related reporting measures). Regarding one of the measures, the 2015 settlement agreement indicated that “Navy surface vessels operating within the HSTT shall avoid approaching marine mammals head-on and shall maneuver to maintain a 500 yard (457 meter) mitigation zone for observed whales and a 200 yard (183 meter) mitigation zone for all other observed marine mammals (except bow riding dolphins), providing it is safe to do so.” This measure is fully included in this final rule. Regarding the other measure, the settlement agreement included several related reporting requirements for NMFS to implement in the event the discovery of an injured or dead marine mammal triggered certain Navy reporting requirements included in the 2013 rule. These reporting requirements are not included in this rule both because it is not the role of 101(a)(5)(A) regulations to require reporting and notifications by NMFS to others (where appropriate notice and opportunity for public involvement is already provided for under the statute) and this reporting by NMFS did not further the conservation of marine mammals. Last, these settlement agreement reporting measures highlighted inconsistencies between some of the measures required under the 2013 regulations and those inconsistencies have been resolved; the 2018 LOAs include updated reporting requirements.

NMFS' and the Navy's analysis of mitigation areas is described in the subsections above and the description of areas included in the final rule are described in the subsection below. In order to assist the reader in understanding the differences in mitigation areas between the terms of the 2015 settlement agreement (as a result of the ruling in Conservation Council for Hawaii v. National Marine Fisheries Service, 97 F. Supp.3d 1210 (D. Haw. 2015)) and this final rule, we offer the following:

  • Figures 1, 2, 3, and 4 below depict the settlement mitigation areas and the HSTT Mitigation Areas for Hawaii and SOCAL.
  • Table 44 below compares the mitigation requirements from the 2015 settlement agreement areas to the mitigation requirements for the areas specified in this final rule (noting also the species for which impacts will be reduced).
  • Table K.2-2 of Appendix K in the HSTT FEIS/OEIS includes a comparison of the settlement agreement areas to mitigation areas for this rulemaking period by species and BIAs.
  • NMFS' CetSound website includes an interactive map depicting the BIAs for all species and stocks (there are 12 overlapping BIAs in the main Hawaiian Islands, making it difficult to present them effectively in a static map). See https://cetsound.noaa.gov/​biologically-important-area-map.
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Table 44—Comparison of Mitigation Areas in Effect 2015-2018 Under the 2015 Settlement Agreement to Mitigation Areas Implemented Under 2018 Final Rule

Litigation settlement (2015-December 2018)HSTT final MMPA incidental take rule (December 2018-2023)
HawaiiHawaii
Area 1-A Hawaii Island (North, South, East) (year-round). (a) Prohibit the use of MFAS for training and testing activities during both MTEs and unit-level training; and (b) prohibit the use of in-water explosives for training and testing activities. Reduces impacts to false killer whales, pygmy killer whales, short-finned pilot whales, bottlenose dolphins, spinner dolphins, Cuvier's beaked whales, and Blainville's beaked whalesHawaii Island Mitigation Area (year-round). Incorporates parts of settlement measures 1-A through 1-E and 2-A through 2-E. Navy will minimize the use of MFAS (MF1 and MF4) and will not use explosives during testing and training. Reduces impacts on ESA-listed false killer whales and monk seals, two species of beaked whales, humpback whales, and other species.
Area 1-B Hawaii Island (Northwest) (year-round). Limit the use of MFAS for training and testing activities during MTEs to one Rim of the Pacific in 2016, one Rim of the Pacific in 2018, three Undersea Warfare Exercises per calendar year, and one Independent Deployer Certification Exercise per calendar year. Reduces impacts to humpback whales, false killer whales, short-finned pilot whales, melon-headed whales, bottlenose dolphins, spinner dolphins, Cuvier's beaked whales, and Blainville's beaked whales4-Islands Region Mitigation Area (November 1-April 15 for active sonar, year-round for explosives). Incorporates parts of settlement Areas 1-A, 1-B, 1-C, 1-D, 1-E, 2-A, 2-B, and 2-C and humpback reporting area. Navy will not use MFAS (MF1) or explosives in this mitigation area during training and testing. Reduces impacts to humpback whales, ESA-listed false killer whales and monk seals, and some dolphin species. • Humpback Whale Special Reporting Areas (December 15-April 15). Incorporates parts of settlement areas 1-B, 1-C, 1-D, 2-A, 2-B, and 2-D, humpback special reporting area and humpback cautionary area. Navy will report the hours of MF1 used in these areas in training and testing activity reports. • Humpback Whale Awareness Notification Message Area (November-April). Navy will issue a seasonal awareness notification message to alert ships and aircraft operating in the area to the possible presence of concentrations of large whales, including humpback whales.
Area 1-C Hawaii Island (West) (year-round). (a) Limit the use of MFAS for training and testing activities during MTEs to one Rim of the Pacific in 2016, one Rim of the Pacific in 2018, three Undersea Warfare Exercises per calendar year, and one Independent Deployer Certification Exercise per calendar year; (b) prohibit the use of MFAS for training and testing activities during unit-level training (excluding unit-level training conducted by participants in an ongoing MTE; and (c) prohibit the use of in-water explosives for training and testing activities. Reduces impacts to humpback whales, false killer whales, dwarf sperm whales, pygmy killer whales, short-finned pilot whales, bottlenose dolphins, spotted dolphins, spinner dolphins, rough toothed dolphins, Cuvier's beaked whales, and Blainville's beaked whales
Area 1-D Hawaii Island (Southwest) (year-round). (a) Limit the use of MFAS for training and testing activities during MTEs to one Rim of the Pacific in 2016, one Rim of the Pacific in 2018, three Undersea Warfare Exercises per calendar year, one Independent Deployer Certification Exercise per calendar year, and one Sustainment Exercise per calendar year; (b) prohibit the use of MFAS for training and testing activities during unit-level training (excluding unit-level training conducted by participants in ongoing MTEs ); and (c) prohibit the use of in-water explosives for training and testing activities. Reduces impacts to dwarf sperm whales, pygmy killer whales, short-finned pilot whales, bottlenose dolphins, spotted dolphins, spinner dolphins, rough-toothed dolphins, Cuvier's beaked whales, and Blainville's beaked whales
Area 1-E and 2-E Hawaii Island (nearshore Northwest) (year-round). Require that all surface vessels use extreme caution and proceed at safe speed so they can take proper and effective action to avoid a collision with any sighted object or disturbance, and can be stopped within a distance appropriate to the prevailing circumstances and conditions. Reduces impacts to dwarf sperm whales, false killer whales, pygmy killer whales, melon-headed whales, bottlenose dolphins, spotted dolphins, spinner dolphins, rough-toothed dolphins, and Blainville's beaked whales
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Area 2-A (Southeast Oahu, Southwest Molokai, Penguin Bank) (year-round). (a) Prohibit the use of MFAS for training and testing activities during MTEs; (b) prohibit the use of in-water explosives for training and testing activities; and (c) require that all surface vessels use extreme caution and proceed at safe speed so they can take proper and effective action to avoid a collision with any sighted object or disturbance, and can be stopped within a distance appropriate to the prevailing circumstances and conditions. Reduces impacts to humpback whales, false killer whales, bottlenose dolphins, and spinner dolphins
Area 2-B (South Molokai, East Maui, Penguin Bank) (year-round). (a) Prohibit the use of in-water explosives for training and testing activities; and (b) require that all surface vessels use extreme caution and proceed at safe speed so they can take proper and effective action to avoid a collision with any sighted object or disturbance, and can be stopped within a distance appropriate to the prevailing circumstances and conditions. Reduces impacts to humpback whales, bottlenose dolphins, spotted dolphins, and spinner dolphins
Area 2-C (North Molokai, North Maui) (year-round). (a) Prohibit the use of MFAS for training and testing activities during MTEs; (b) implement a Protective Measure Assessment Protocol measure advising Commanding Officers that the area is false killer whale habitat and that they should avoid using MFAS during unit-level training within the area whenever practicable; and (c) prohibit the use of in-water explosives for training and testing activities (within the overlap of Area 2-B and Area 2-C, the restrictions imposed in Area 2-B and Area 2-C both apply). Reduces impacts to false killer whales, bottlenose dolphins, and spinner dolphins
Area 2-D (Southeast Oahu, Northwest Molokai) (year-round). Prohibit the use of in-water explosives for training and testing activities. Reduces impacts to false killer whales, bottlenose dolphins, and spinner dolphins
Southern CaliforniaSouthern California
Area 3-A (San Diego Arc, coastal) (June 1-October 31). (a) Prohibit the use of MFAS for training and testing activities during MTEs and unit-level training; and (b) require that all surface vessels use extreme caution and proceed at safe speed so they can take proper and effective action to avoid a collision with any sighted object or disturbance, and can be stopped within a distance appropriate to the prevailing circumstances and conditions. Reduces impacts to blue and gray whalesSan Diego Arc, San Nicolas Island, and Santa Monica/Long Beach Mitigation Areas (June 1-October 31). Incorporates parts of settlement areas 3-A, 3-B, 3-C, 4-A, 4-B, 4-C, and 4-D. Navy will minimize the use of MFAS (MF1) within the three Mitigation Areas during training and testing. Within the San Diego Arc Mitigation Area, Navy will not use explosives during large-caliber gunnery, torpedo, bombing, and missile activities during testing and training. Within the San Nicolas Island Mitigation Area Navy will not use explosives during mine warfare, large-caliber gunnery, torpedo, bombing and missile activities during training. Within the Santa Monica/Long Beach Mitigation Area, Navy will not use explosives during mine warfare, large-caliber gunnery, torpedo, bombing, and missile (including 2.75″ rockets) activities during training and testing. Reduces impacts primarily to blue whales, but also gray and fin whales. • Santa Barbara Island Mitigation Area (year-round). Incorporates parts of settlement areas 4A, Channel Island NMS. Navy will not use MFAS (MF1) and explosives in small-, medium-, and large-caliber gunnery, torpedo, bombing, and missile activities during unit-level training or MTEs. Reduces impacts to numerous marine mammal species that use the Channel Islands NMS and partially overlap areas for blue whales and gray whales. • Blue Whale (June-October), Gray Whale (November-March), and Fin Whale (November-May) Awareness Notification Message Areas. Navy will issue a seasonal awareness notification message to alert ships and aircraft operating in the area to the possible presence of concentrations of large whales, particularly blue, gray, and fin whales.
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Area 3-B (San Diego Arc, coastal) (June 1-October 31). (a) Prohibit the use of MFAS for training and testing activities during MTEs and unit-level training, except for system checks; (b) implement a seasonal Protective Measure Assessment Protocol measure advising Commanding Officers that the area is blue whale habitat and that they should avoid conducting system checks within the area whenever practicable; and (c) require that all surface vessels use extreme caution and proceed at safe speed so they can take proper and effective action to avoid a collision with any sighted object or disturbance, and can be stopped within a distance appropriate to the prevailing circumstances and conditions. Reduces impacts to blue and gray whales
Area 3-C (Santa Monica Bay to Long Beach, coastal) (November 1-May 20). Require that all surface vessels use extreme caution and proceed at safe speed so they can take proper and effective action to avoid a collision with any sighted object or disturbance, and can be stopped within a distance appropriate to the prevailing circumstances and conditions. Reduces impacts to blue and gray whales
Area 4-A (East of San Nicholas Island) (year-round). (a) Prohibit the use of MFAS for training and testing activities during MTEs and unit-level training; and (b) prohibit the use of in-water explosives for training and testing activities. Reduces impacts to blue and gray whales
Area 4-B (east of Santa Catalina Island) (year-round). Prohibit the use of MFAS for training and testing activities during MTEs and unit-level training. Reduces impacts to gray whales
Area 4-C (Tanner-Cortes Bank) (June 1-October 31). Require that all surface vessels use extreme caution and proceed at safe speed so they can take proper and effective action to avoid a collision with any sighted object or disturbance, and can be stopped within a distance appropriate to the prevailing circumstances and conditions. Reduces impacts to blue and gray whales
Area 4-D (south of 4-A) (year-round). Require all surface vessels to use extreme caution and proceed at a safe speed so they can take proper and effective action to avoid a collision with any sighted object or disturbance, and can be stopped within a distance appropriate to the prevailing circumstances and conditions. Reduces impacts to gray whales

As described above, NMFS analyzed the Navy's activities as set forth in its application, the impacts of those activities, the proposed mitigation, and potential additional mitigation (including the 2015 settlement agreement measures) pursuant to the “least practicable adverse impact” standard to determine the appropriate mitigation to include in these regulations. Some of the measures that were included in the 2015 settlement agreement are included in this final rule (for example, the vast majority of the area in Hawaii included in the mitigation for the settlement agreement is included in Mitigation Areas in this rule), while some are not (for example, because of the instrumented ranges and specific training needs in SOCAL, less of the area covered in the settlement agreement is included as Mitigation Areas in this rule). As noted previously, Appendix K (Geographic Mitigation Assessment) of the HSTT FEIS/OEIS includes a detailed analysis of all of the potential mitigation areas and associated measures (including the settlement measures addressed in this section), in the context of both reduction of marine mammal impacts and practicability. NMFS has independently reviewed Appendix K (Geographic Mitigation Assessment), determined that the analysis reflects the best available science, and used the information to support our findings outlined in this Mitigation Measures section. A summary of the rationale for not adopting the relatively small subset of remaining 2015 settlement agreement measures that were not carried forward follows.

In Hawaii, about 85 percent of the area that was covered by 2015 settlement areas is covered by mitigation areas in this final rule (see Figures 1 and 2 above). The protected area around the island of Hawaii is the same in this rule as it was in the 2015 settlement agreement (Hawaii Mitigation Area), with the difference being that the settlement agreement included mitigation on Penguin Bank and in a couple of areas north of Molokai and Maui that are not included in the 4-Islands Mitigation Area in this final rule. As explained in more detail in the full analysis in Section 3 of Appendix K of the HSTT FEIS/OEIS, Penguin Bank offers critical shallow and constrained conditions for Navy training (especially submarines) that are not available anywhere else in Hawaii. The areas north of Molokai and Maui that are not included in the current 4-Islands Mitigation Area are similarly critical for certain exercises that specifically include torpedo exercises deliberately conducted in this area north of the islands to avoid the other suitable training areas between the four islands where humpback whale density is higher. The 2015 settlement agreement mitigation restricted all MFAS and explosive use on Penguin Bank (area 2-A), however, as the Navy explains, this MFAS restriction is impracticable in that it would have unacceptable impacts on their training and testing capabilities. In addition, the Navy does not typically use explosives in this area. For the settlement areas north of Molokai and Maui that are not covered in the rule (area 2-B and part of area 2-C), the settlement agreement restricted explosive use but did not restrict MFAS in the 2-B area. Explosive use in these areas is also already rare, but for the reasons described in Appendix K, Start Printed Page 66958restricting MFAS use is impracticable and would have unacceptable impacts on training and testing. We also note that while it is not practicable to restrict MFAS use on Penguin Bank, MFAS use is relatively low and we have identified it as a special reporting area for which the Navy will report the MFAS use in that area to inform adaptive management discussions in the future. Additionally, some of the areas that the 2015 settlement agreement identified included language regarding extra vigilance intended to avoid vessel strikes. Neither NMFS nor the Navy thought that inclusion of this term as written would necessarily reduce the probability of a vessel strike, so instead we have included the Humpback Whale Awareness Notification provision, which sends out a message to all Navy vessels in Hawaii during the time that humpback whales are present. Last we note that the 2015 settlement mitigation areas with MFAS restrictions sometimes excluded all MFAS, while sometimes they limited the number of MTEs that could occur (with no limit on any particular type of sonar, meaning that hull-mounted surface ship sonar could be operated), whereas the sonar restrictions in this final rule limit the use of surface ship hull-mounted sonar, which is the source that results in the vast majority of incidental takes.

For SOCAL, the 2015 settlement areas had four primary objectives: Reducing impacts in blue whale feeding areas, reducing the likelihood of large whale vessel strikes, minimizing incidental take of gray whales, and minimizing incidental take of beaked whales in areas that the plaintiffs argued were specifically important to beaked whales. As noted previously, of the four blue whale feeding areas in SOCAL, the Navy mitigation areas in this rule fully cover three of them (those associated with settlement areas 3-A, 3-B, 4-A, and 4-B in the 2015 settlement agreement) and limit surface ship hull-mounted MFAS and explosive use. In fact, we included protections for the southern end of a blue whale feeding BIA (Santa Monica/Long Beach area), by limiting hull-mounted MFAS and explosives that were not included in the 2015 settlement areas. The fourth blue whale feeding BIA, Tanner-Cortes Banks, provides unique and irreplaceable shallow-water conditions that are critical for shallow-water training and testing (especially for submarines) and that are not available elsewhere in SOCAL, along with a shallow-water minefield training range. Notably, in a satellite tracking study of blue whales in Southern California from 2014 to 2017, Tanner-Cortes Banks was only transited minimally by individual blue whales (Mate et al., 2018). Limiting activities in this area would inhibit the Navy's ability to successfully test and train and is impracticable. In fact, the 2015 settlement area at Tanner-Cortes Banks did not limit MFAS or explosive use. Rather, Tanner-Cortes Banks (area 4-C), settlement area 4-D, and the large settlement area close to shore (area 3-C) each only had one associated protective measure, which was language regarding extra vigilance intended to avoid vessel strikes. However, neither NMFS nor the Navy thought that inclusion of this term as written would necessarily reduce the probability of a vessel strike, so instead we have included the Blue Whale, Gray Whale, and Fin Whale Awareness Notification Area, which sends out a message to all Navy vessels in SOCAL during the time these large whales are present and will more effectively help to reduce the probability of ship strike.

The remaining areas covered by 2015 settlement mitigation areas that are not covered by mitigation areas in this final rule (area 4-B and the outer edges of area 4-A, which does not align exactly with the blue whale BIA like the current Navy mitigation area does) were intended to reduce impacts on gray whales and to provide some sort of protection for beaked whales. However, NMFS and the Navy disagree that the remaining 2015 settlement areas provide the protection the plaintiffs assert. As noted earlier, gray whales migrate primarily through a 5 to 10 km corridor along the West Coast, with some individuals occasionally ranging offshore (noting that mother/calf pairs always stay very close to shore), which resulted in the BIA recognizing a 47-km buffer beyond the 5 to 10 km main migration corridor, but also expanding the BIA further offshore in order to encompass the Channel Islands, where some individuals also sometimes range further. Prohibiting activities outside of the main migration corridor in an area where gray whales may be present only occasionally is not expected to meaningfully reduce effects, especially if the mitigation area is small compared to the much larger buffer area and the same amount of activities occur outside of the mitigation area, but still in the larger area that gray whales occupy. Regarding beaked whales, the plaintiffs in the Conservation Council for Hawaii case indicated that settlement area 4-B would provide important habitat for beaked whales based on tagging data from two whales in 2014. However, while beaked whales are present in the area, tagging data through 2018 (for 27 Cuvier's beaked whales) shows that these whales have site fidelity to the SOAR Range and typically do not move toward the 2015 settlement areas when they do leave SOAR. In other words, since the 2015 settlement area is not an area of known particular importance for these whales, protecting it would not be expected to reduce impacts. Appendix K of the HSTT FEIS/OEIS explains in detail why additional limitations in this area would inhibit training and testing and thereby be impracticable, and the Comments and Responses section of this rule addresses these recommendations specifically. In summary, the mitigation areas identified in this rule address the valid concerns that were targeted through the 2015 settlement agreement, but areas that were either impracticable to continue to implement or do not provide a reduction in impacts on marine mammals were not carried forward.

The final Procedural Mitigation measures and Mitigation Area measures are described in the sections below.

Final Procedural Mitigation

Procedural mitigation is mitigation that the Navy will implement whenever and wherever an applicable training or testing activity takes place within the HSTT Study Area. The Navy customizes procedural mitigation for each applicable activity category or stressor. Procedural mitigation generally involves: (1) The use of one or more trained Lookouts to diligently observe for specific biological resources (including marine mammals) within a mitigation zone, (2) requirements for Lookouts to immediately communicate sightings of specific biological resources to the appropriate watch station for information dissemination, and (3) requirements for the watch station to implement mitigation (e.g., halt an activity) until certain recommencement conditions have been met. The first procedural mitigation (Table 45) is designed to aid Lookouts and other applicable personnel with their observation, environmental compliance, and reporting responsibilities. The remainder of the procedural mitigation measures (Tables 45 through Tables 64) are organized by stressor type and activity category and includes acoustic stressors (i.e., active sonar, air guns, pile driving, weapons firing noise), explosive stressors (i.e., sonobuoys, torpedoes, medium-caliber and large-caliber projectiles, missiles and rockets, bombs, sinking exercises, mines, underwater demolition multiple charge mat weave and obstacles loading, anti-swimmer grenades), and physical disturbance and strike stressors (i.e., vessel movement, towed in-water devices, small-, medium-, and large-caliber non-explosive practice munitions, non-explosive missiles and rockets, non-explosive bombs and mine shapes).

Table 45-Procedural Mitigation for Environmental Awareness and Education

Procedural Mitigation Description
Stressor or Activity:
• All training and testing activities, as applicable.
Mitigation Requirements:
• Appropriate Navy personnel (including civilian personnel) involved in mitigation and training or testing activity reporting under the specific activities must complete one or more modules of the U.S. Navy Afloat Environmental Compliance Training Series, as identified in their career path training plan. Modules include:
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—Introduction to the U.S. Navy Afloat Environmental Compliance Training Series. The introductory module provides information on environmental laws (e.g., ESA, MMPA) and the corresponding responsibilities that are relevant to Navy training and testing activities. The material explains why environmental compliance is important in supporting the Navy's commitment to environmental stewardship.
—Marine Species Awareness Training. All bridge watch personnel, Commanding Officers, Executive Officers, maritime patrol aircraft aircrews, anti‐submarine warfare and mine warfare rotary-wing aircrews, Lookouts, and equivalent civilian personnel must successfully complete the Marine Species Awareness Training prior to standing watch or serving as a Lookout. The Marine Species Awareness Training provides information on sighting cues, visual observation tools and techniques, and sighting notification procedures. Navy biologists developed Marine Species Awareness Training to improve the effectiveness of visual observations for biological resources, focusing on marine mammals and sea turtles, and including floating vegetation, jellyfish aggregations, and flocks of seabirds.
—U.S. Navy Protective Measures Assessment Protocol. This module provides the necessary instruction for accessing mitigation requirements during the event planning phase using the Protective Measures Assessment Protocol software tool.
—U.S. Navy Sonar Positional Reporting System and Marine Mammal Incident Reporting. This module provides instruction on the procedures and activity reporting requirements for the Sonar Positional Reporting System and marine mammal incident reporting.

Procedural Mitigation for Acoustic Stressors

Mitigation measures for acoustic stressors are provided in Tables 46 through 49.

Procedural Mitigation for Active Sonar

Procedural mitigation for active sonar is described in Table 46 below.

Table 46—Procedural Mitigation for Active Sonar

Procedural Mitigation Description
Stressor or Activity:
Low-frequency active sonar, mid-frequency active sonar, high-frequency active sonar.
—For vessel-based activities, mitigation applies only to sources that are positively controlled and deployed from manned surface vessels (e.g., sonar sources towed from manned surface platforms).
—For aircraft-based activities, mitigation applies only to sources that are positively controlled and deployed from manned aircraft that do not operate at high altitudes (e.g., rotary-wing aircraft). Mitigation does not apply to active sonar sources deployed from unmanned aircraft or aircraft operating at high altitudes (e.g., maritime patrol aircraft).
Number of Lookouts and Observation Platform:
Hull-mounted sources:
—1 Lookout: Platforms with space or manning restrictions while underway (at the forward part of a small boat or ship) and platforms using active sonar while moored or at anchor (including pierside).
—2 Lookouts: Platforms without space or manning restrictions while underway (at the forward part of the ship).
Sources that are not hull-mounted:
—1 Lookout on the ship or aircraft conducting the activity.
Mitigation Requirements:
Mitigation zones:
—During the activity, at 1,000 yd Navy personnel must power down 6 dB, at 500 yd, Navy personnel must power down an additional 4 dB (for a total of 10 dB), and at 200 yd Navy personnel must shut down for low-frequency active sonar ≥200 decibels (dB) and hull-mounted mid-frequency active sonar.
—200 yd shut down for low-frequency active sonar <200 dB, mid-frequency active sonar sources that are not hull-mounted, and high-frequency active sonar.
Prior to the initial start of the activity (e.g., when maneuvering on station):
—Observe the mitigation zone for floating vegetation; if floating vegetation is observed, relocate or delay the start until the mitigation zone is clear.
—Observe the mitigation zone for marine mammals; if marine mammals are observed, relocate or delay the start of active sonar transmission.
During the activity:
—Low-frequency active sonar ≥200 decibels (dB) and hull-mounted mid-frequency active sonar: Navy personnel must observe the mitigation zone for marine mammals; power down active sonar transmission by 6 dB if marine mammals are observed within 1,000 yd of the sonar source; power down an additional 4 dB (for a total of 10 dB total) within 500 yd; cease transmission within 200 yd.
—Low-frequency active sonar <200 dB, mid-frequency active sonar sources that are not hull-mounted, and high-frequency active sonar: Observe the mitigation zone for marine mammals; cease active sonar transmission if marine mammals are observed within 200 yd of the sonar source.
Commencement/recommencement conditions after a marine mammal sighting before or during the activity:
—Navy personnel must allow a sighted marine mammal to leave the mitigation zone prior to the initial start of the activity (by delaying the start) or during the activity (by not recommencing or powering up active sonar transmission) until one of the following conditions has been met: (1) The animal is observed exiting the mitigation zone; (2) the animal is thought to have exited the mitigation zone based on a determination of its course, speed, and movement relative to the sonar source; (3) the mitigation zone has been clear from any additional sightings for 10 min. for aircraft-deployed sonar sources or 30 min. for vessel-deployed sonar sources; (4) for mobile activities, the active sonar source has transited a distance equal to double that of the mitigation zone size beyond the location of the last sighting; or (5) for activities using hull-mounted sonar, the ship concludes that dolphins are deliberately closing in on the ship to ride the ship's bow wave, and are therefore out of the main transmission axis of the sonar (and there are no other marine mammal sightings within the mitigation zone).
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Procedural Mitigation for Air Guns

Procedural mitigation for air guns is described in Table 47 below.

Table 47—Procedural Mitigation for Air Guns

Procedural Mitigation Description
Stressor or Activity:
• Air guns.
Number of Lookouts and Observation Platform:
1 Lookout must be positioned on a ship or pierside.
Mitigation Requirements:
Mitigation zone:
—150 yd around the air gun
Prior to the initial start of the activity (e.g., when maneuvering on station):
—Observe the mitigation zone for floating vegetation; if floating vegetation is observed, relocate or delay the start until the mitigation zone is clear.
—Observe the mitigation zone for marine mammals; if marine mammals are observed, relocate or delay the start of air gun use.
During the activity:
—Observe the mitigation zone for marine mammals; if marine mammals are observed, cease air gun use.
Commencement/recommencement conditions after a marine mammal sighting before or during the activity:
—Navy personnel must allow a sighted marine mammal to leave the mitigation zone prior to the initial start of the activity (by delaying the start) or during the activity (by not recommencing air gun use) until one of the following conditions has been met: (1) The animal is observed exiting the mitigation zone; (2) the animal is thought to have exited the mitigation zone based on a determination of its course, speed, and movement relative to the air gun; (3) the mitigation zone has been clear from any additional sightings for 30 min.; or (4) for mobile activities, the air gun has transited a distance equal to double that of the mitigation zone size beyond the location of the last sighting.

Procedural Mitigation for Pile Driving

Procedural mitigation for pile driving is described in Table 48 below.

Table 48—Procedural Mitigation for Pile Driving

Procedural mitigation description
Stressor or Activity:
Pile driving and pile extraction sound during Elevated Causeway System training.
Number of Lookouts and Observation Platform:
1 Lookout must be positioned on the shore, the elevated causeway, or a small boat.
Mitigation Requirements:
Mitigation zone:
—100 yd around the pile.
Prior to the initial start of the activity (for 30 min.):
—Observe the mitigation zone for floating vegetation; if floating vegetation is observed, delay the start until the mitigation zone is clear.
—Observe the mitigation zone for marine mammals; if marine mammals are observed, delay the start of pile driving or vibratory pile extraction.
During the activity:
—Observe the mitigation zone for marine mammals; if marine mammals are observed, cease impact pile driving or vibratory pile extraction.
Commencement/recommencement conditions after a marine mammal sighting before or during the activity:
—Navy personnel must allow a sighted marine mammal to leave the mitigation zone prior to the initial start of the activity (by delaying the start) or during the activity (by not recommencing pile driving or pile extraction) until one of the following conditions has been met: (1) The animal is observed exiting the mitigation zone; (2) the animal is thought to have exited the mitigation zone based on a determination of its course, speed, and movement relative to the pile driving location; or (3) the mitigation zone has been clear from any additional sightings for 30 min.

Procedural Mitigation for Weapons Firing Noise

Procedural mitigation for weapons firing noise is described in Table 49 below.

Table 49—Procedural Mitigation for Weapons Firing Noise

Procedural mitigation description
Stressor or Activity:
Weapons firing noise associated with large-caliber gunnery activities.
Number of Lookouts and Observation Platform:
1 Lookout must be positioned on the ship conducting the firing.
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—Depending on the activity, the Lookout could be the same one provided for under Explosive Medium-Caliber and Large-Caliber Projectiles or under Small-, Medium, and Large-Caliber Non-Explosive Practice Munitions.
Mitigation Requirements:
Mitigation zone:
—30° on either side of the firing line out to 70 yd from the muzzle of the weapon being fired.
Prior to the initial start of the activity:
—Observe the mitigation zone for floating vegetation; if floating vegetation is observed, relocate or delay the start of weapons firing until the mitigation zone is clear.
—Observe the mitigation zone for marine mammals; if marine mammals are observed, relocate or delay the start of weapons firing.
During the activity:
—Observe the mitigation zone for marine mammals; if marine mammals are observed, cease weapons firing.
Commencement/recommencement conditions after a marine mammal sighting before or during the activity:
—Navy personnel must allow a sighted marine mammal to leave the mitigation zone prior to the initial start of the activity (by delaying the start) or during the activity (by not recommencing weapons firing) until one of the following conditions has been met: (1) The animal is observed exiting the mitigation zone; (2) the animal is thought to have exited the mitigation zone based on a determination of its course, speed, and movement relative to the firing ship; (3) the mitigation zone has been clear from any additional sightings for 30 min.; or (4) for mobile activities, the firing ship has transited a distance equal to double that of the mitigation zone size beyond the location of the last sighting.

Procedural Mitigation for Explosive Stressors

Mitigation measures for explosive stressors are provided in Tables 50 through 59.

Procedural Mitigation for Explosive Sonobuoys

Procedural mitigation for explosive sonobuoys is described in Table 50 below.

Table 50—Procedural Mitigation for Explosive Sonobuoys

Procedural mitigation description
Stressor or Activity:
Explosive sonobuoys.
Number of Lookouts and Observation Platform:
1 Lookout must be positioned must be positioned in an aircraft or on small boat.
• If additional platforms are participating in the activity, personnel positioned in those assets (e.g., safety observers, evaluators) must support observing the mitigation zone for applicable biological resources while performing their regular duties.
Mitigation Requirements:
Mitigation zone:
—600 yd around an explosive sonobuoy.
Prior to the initial start of the activity (e.g., during deployment of a sonobuoy field, which typically lasts 20-30 min.):
—Observe the mitigation zone for floating vegetation; if floating vegetation is observed, relocate or delay the start until the mitigation zone is clear.
—Conduct passive acoustic monitoring for marine mammals; use information from detections to assist visual observations.
—Visually observe the mitigation zone for marine mammals; if marine mammals are observed, relocate or delay the start of sonobuoy or source/receiver pair detonations.
During the activity:
—Observe the mitigation zone for marine mammals; if marine mammals are observed, cease sonobuoy or source/receiver pair detonations.
Commencement/recommencement conditions after a marine mammal sighting before or during the activity:
—Navy personnel must allow a sighted marine mammal to leave the mitigation zone prior to the initial start of the activity (by delaying the start) or during the activity (by not recommencing detonations) until one of the following conditions has been met: (1) The animal is observed exiting the mitigation zone; (2) the animal is thought to have exited the mitigation zone based on a determination of its course, speed, and movement relative to the sonobuoy; or (3) the mitigation zone has been clear from any additional sightings for 10 min. when the activity involves aircraft that have fuel constraints, or 30 min. when the activity involves aircraft that are not typically fuel constrained.
After completion of the activity (e.g., prior to maneuvering off station):
—When practical (e.g., when platforms are not constrained by fuel restrictions or mission-essential follow-on commitments), observe the vicinity of where detonations occurred; if any injured or dead marine mammals are observed, follow established incident reporting procedures.
—If additional platforms are supporting this activity (e.g., providing range clearance), these assets must assist in the visual observation of the area where detonations occurred.

Procedural Mitigation for Explosive Torpedoes

Procedural mitigation for explosive torpedoes is described in Table 51 below.Start Printed Page 66962

Table 51—Procedural Mitigation for Explosive Torpedoes

Procedural mitigation description
Stressor or Activity:
Explosive torpedoes.
Number of Lookouts and Observation Platform:
1 Lookout must be positioned in an aircraft.
If additional platforms are participating in the activity, personnel positioned in those assets (e.g., safety observers, evaluators) must support observing the mitigation zone for applicable biological resources while performing their regular duties.
Mitigation Requirements:
Mitigation zone:
—2,100 yd around the intended impact location.
Prior to the initial start of the activity (e.g., during deployment of the target):
—Observe the mitigation zone for floating vegetation; if floating vegetation is observed, relocate or delay the start until the mitigation zone is clear.
—Conduct passive acoustic monitoring for marine mammals; use information from detections to assist visual observations.
—Visually observe the mitigation zone for marine mammals and jellyfish aggregations; if marine mammals or jellyfish aggregations are observed, relocate or delay the start of firing.
During the activity:
—Observe the mitigation zone for marine mammals and jellyfish aggregations; if marine mammals and jellyfish aggregations are observed, cease firing.
Commencement/recommencement conditions after a marine mammal sighting before or during the activity:
—Navy personnel must allow a sighted marine mammal to leave the mitigation zone prior to the initial start of the activity (by delaying the start) or during the activity (by not recommencing firing) until one of the following conditions has been met: (1) The animal is observed exiting the mitigation zone; (2) the animal is thought to have exited the mitigation zone based on a determination of its course, speed, and movement relative to the intended impact location; or (3) the mitigation zone has been clear from any additional sightings for 10 min. when the activity involves aircraft that have fuel constraints, or 30 min. when the activity involves aircraft that are not typically fuel constrained.
After completion of the activity (e.g., prior to maneuvering off station):
—When practical (e.g., when platforms are not constrained by fuel restrictions or mission-essential follow-on commitments), observe the vicinity of where detonations occurred; if any injured or dead marine mammals are observed, follow established incident reporting procedures.
—If additional platforms are supporting this activity (e.g., providing range clearance), these assets must assist in the visual observation of the area where detonations occurred.

Procedural Mitigation for Medium- and Large-Caliber Projectiles

Procedural mitigation for medium- and large-caliber projectiles is described in Table 52 below.

Table 52—Procedural Mitigation for Explosive Medium-Caliber and Large-Caliber Projectiles

Procedural mitigation description
Stressor or Activity:
Gunnery activities using explosive medium-caliber and large-caliber projectiles.
—Mitigation applies to activities using a surface target.
Number of Lookouts and Observation Platform:
1 Lookout must be on the vessel or aircraft conducting the activity.
—For activities using explosive large-caliber projectiles, depending on the activity, the Lookout could be the same as the one described for Weapons Firing Noise.
If additional platforms are participating in the activity, Navy personnel positioned in those assets (e.g., safety observers, evaluators) must support observing the mitigation zone for applicable biological resources while performing their regular duties.
Mitigation Requirements:
Mitigation zones:
—200 yd around the intended impact location for air-to-surface activities using explosive medium-caliber projectiles.
—600 yd around the intended impact location for surface-to-surface activities using explosive medium-caliber projectiles.
—1,000 yd around the intended impact location for surface-to-surface activities using explosive large-caliber projectiles.
Prior to the initial start of the activity (e.g., when maneuvering on station):
—Observe the mitigation zone for floating vegetation; if floating vegetation is observed, relocate or delay the start until the mitigation zone is clear.
—Observe the mitigation zone for marine mammals; if marine mammals are observed, relocate or delay the start of firing.
During the activity:
—Observe the mitigation zone for marine mammals; if marine mammals are observed, cease firing.
Commencement/recommencement conditions after a marine mammal sighting before or during the activity:
—Navy personnel must allow a sighted marine mammal to leave the mitigation zone prior to the initial start of the activity (by delaying the start) or during the activity (by not recommencing firing) until one of the following conditions has been met: (1) The animal is observed exiting the mitigation zone; (2) the animal is thought to have exited the mitigation zone based on a determination of its course, speed, and movement relative to the intended impact location; (3) the mitigation zone has been clear from any additional sightings for 10 min. for aircraft-based firing or 30 min. for vessel-based firing; or (4) for activities using mobile targets, the intended impact location has transited a distance equal to double that of the mitigation zone size beyond the location of the last sighting.
After completion of the activity (e.g., prior to maneuvering off station):
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—When practical (e.g., when platforms are not constrained by fuel restrictions or mission-essential follow-on commitments), observe the vicinity of where detonations occurred; if any injured or dead marine mammals are observed, follow established incident reporting procedures.
—If additional platforms are supporting this activity (e.g., providing range clearance), these assets must assist in the visual observation of the area where detonations occurred.

Procedural Mitigation for Explosive Missiles and Rockets

Procedural mitigation for explosive missiles and rockets is described in Table 53 below.

Table 53—Procedural Mitigation for Explosive Missiles and Rockets

Procedural mitigation description
Stressor or Activity:
Aircraft-deployed explosive missiles and rockets.
—Mitigation applies to activities using a surface target.
Number of Lookouts and Observation Platform:
1 Lookout must be positioned in an aircraft.
If additional platforms are participating in the activity, Navy personnel positioned in those assets (e.g., safety observers, evaluators) must support observing the mitigation zone for applicable biological resources while performing their regular duties.
Mitigation Requirements:
Mitigation zones:
—900 yd around the intended impact location for missiles or rockets with 0.6-20 lb. net explosive weight.
—2,000 yd around the intended impact location for missiles with 21-500 lb. net explosive weight.
Prior to the initial start of the activity (e.g., during a fly-over of the mitigation zone):
—Observe the mitigation zone for floating vegetation; if floating vegetation is observed, relocate or delay the start until the mitigation zone is clear.
—Observe the mitigation zone for marine mammals; if marine mammals are observed, relocate or delay the start of firing.
During the activity:
—Observe the mitigation zone for marine mammals; if marine mammals are observed, cease firing.
Commencement/recommencement conditions after a marine mammal sighting before or during the activity:
—Navy personnel must allow a sighted marine mammal to leave the mitigation zone prior to the initial start of the activity (by delaying the start) or during the activity (by not recommencing firing) until one of the following conditions has been met: (1) The animal is observed exiting the mitigation zone; (2) the animal is thought to have exited the mitigation zone based on a determination of its course, speed, and movement relative to the intended impact location; or (3) the mitigation zone has been clear from any additional sightings for 10 min. when the activity involves aircraft that have fuel constraints, or 30 min. when the activity involves aircraft that are not typically fuel constrained.
After completion of the activity (e.g., prior to maneuvering off station):
—When practical (e.g., when platforms are not constrained by fuel restrictions or mission-essential follow-on commitments), observe for marine mammals in the vicinity of where detonations occurred; if any injured or dead marine mammals are observed, follow established incident reporting procedures.
—If additional platforms are supporting this activity (e.g., providing range clearance), these assets must assist in the visual observation of the area where detonations occurred.

Procedural Mitigation for Explosive Bombs

Procedural mitigation for explosive bombs is described in Table 54 below.

Table 54—Procedural Mitigation for Explosive Bombs

Procedural mitigation description
Stressor or Activity:
Explosive bombs.
Number of Lookouts and Observation Platform:
1 Lookout must be positioned in the aircraft conducting the activity.
If additional platforms are participating in the activity, Navy personnel positioned in those assets (e.g., safety observers, evaluators) must support observing the mitigation zone for applicable biological resources while performing their regular duties.
Mitigation Requirements:
Mitigation zone:
—2,500 yd around the intended target.
Prior to the initial start of the activity (e.g., when arriving on station):
—Observe the mitigation zone for floating vegetation; if floating vegetation is observed, relocate or delay the start of bomb deployment until the mitigation zone is clear.
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—Observe the mitigation zone for marine mammals; if marine mammals are observed, relocate or delay the start of bomb deployment.
During the activity (e.g., during target approach):
—Observe the mitigation zone for marine mammals; if marine mammals are observed, cease bomb deployment.
Commencement/recommencement conditions after a marine mammal sighting before or during the activity:
—Navy personnel must allow a sighted marine mammal to leave the mitigation zone prior to the initial start of the activity (by delaying the start) or during the activity (by not recommencing bomb deployment) until one of the following conditions has been met: (1) The animal is observed exiting the mitigation zone; (2) the animal is thought to have exited the mitigation zone based on a determination of its course, speed, and movement relative to the intended target; (3) the mitigation zone has been clear from any additional sightings for 10 min.; or (4) for activities using mobile targets, the intended target has transited a distance equal to double that of the mitigation zone size beyond the location of the last sighting.
After completion of the activity (e.g., prior to maneuvering off station):
—When practical (e.g., when platforms are not constrained by fuel restrictions or mission-essential follow-on commitments), observe for marine mammals in the vicinity of where detonations occurred; if any injured or dead marine mammals are observed, follow established incident reporting procedures.
—If additional platforms are supporting this activity (e.g., providing range clearance), these assets must assist in the visual observation of the area where detonations occurred.

Procedural Mitigation for Sinking Exercises

Procedural mitigation for sinking exercises is described in Table 55 below.

Table 55—Procedural Mitigation for Sinking Exercises

Procedural mitigation description
Stressor or Activity:
Sinking exercises.
Number of Lookouts and Observation Platform:
2 Lookouts (one must be positioned in an aircraft and one must be on a vessel).
If additional platforms are participating in the activity, Navy personnel positioned in those assets (e.g., safety observers, evaluators) must support observing the mitigation zone for applicable biological resources while performing their regular duties.
Mitigation Requirements:
Mitigation zone:
—2.5 nmi around the target ship hulk.
Prior to the initial start of the activity (90 min. prior to the first firing):
—Conduct aer