[Federal Register Volume 90, Number 187 (Tuesday, September 30, 2025)]
[Notices]
[Pages 46834-46861]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-18907]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XF080]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Ketchikan Dock Company, LLC's
Ketchikan Berth IV Expansion Project in the East Tongass Narrows,
Alaska
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments on proposed authorization and possible renewal.
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SUMMARY: NMFS has received a request from the Ketchikan Dock Company,
LLC for authorization to take marine mammals incidental to construction
work for the Ketchikan Berth IV Expansion Project in Ketchikan, Alaska
in the East Tongass Narrows. Pursuant to the Marine Mammal Protection
Act (MMPA), NMFS is requesting comments on its proposal to issue an
incidental harassment authorization (IHA) to incidentally take marine
mammals during the specified activities. NMFS is also requesting
comments on a possible one-time, 1-year renewal that could be issued
under certain circumstances and if all requirements are met, as
described in Request for Public Comments at the end of this notice.
NMFS will consider public comments prior to making any final decision
on the issuance of the requested MMPA authorization and agency
responses will be summarized in the final notice of our decision.
DATES: Comments and information must be received no later than October
30, 2025.
[[Page 46835]]
ADDRESSES: Comments should be addressed to Permits and Conservation
Division, Office of Protected Resources, National Marine Fisheries
Service and should be submitted via email to [email protected].
Electronic copies of the application and supporting documents, as well
as a list of the references cited in this document, may be obtained
online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities. In
case of problems accessing these documents, please call the contact
listed below.
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments, including all attachments, must
not exceed a 25-megabyte file size. All comments received are a part of
the public record and will generally be posted online at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act without change. All personal identifying
information (e.g., name, address) voluntarily submitted by the
commenter may be publicly accessible. Do not submit confidential
business information or otherwise sensitive or protected information.
FOR FURTHER INFORMATION CONTACT: Kelsey Potlock, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. 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 proposed or, if the taking is limited to harassment, a notice of a
proposed IHA is provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of the species or stocks for
taking for certain subsistence uses (collectively referred to as
``mitigation''); and requirements pertaining to the monitoring and
reporting of the takings. The definitions of all applicable MMPA
statutory terms used above are included in the relevant sections below
and can be found in section 3 of the MMPA (16 U.S.C. 1362) and NMFS
regulations at 50 CFR 216.103.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an IHA)
with respect to potential impacts on the human environment.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 (IHAs with no anticipated serious injury or
mortality) of the Companion Manual for NAO 216-6A, which do not
individually or cumulatively have the potential for significant impacts
on the quality of the human environment and for which we have not
identified any extraordinary circumstances that would preclude this
categorical exclusion. Accordingly, NMFS has preliminarily determined
that the issuance of the proposed IHA qualifies to be categorically
excluded from further NEPA review.
Summary of Request
On June 10, 2025, NMFS received a request from the Ketchikan Dock
Company, LLC (KDC), for an IHA to take marine mammals incidental to
construction activities using pile driving and Down-the-Hole (DTH)
drilling in Ketchikan, Alaska in the East Tongass Narrows. Following
NMFS' review of the application(s), KDC submitted a revised version on
August 1, 2025. The application was deemed adequate and complete on
September 2, 2025. KDC's request is for take of 8 species of marine
mammals (consisting of 11 stocks) by Level B harassment and, for a
subset of these species (i.e., 7 species (8 stocks)), by Level A
harassment. Neither KDC nor NMFS expect serious injury or mortality to
result from this activity and, therefore, an IHA is appropriate.
Description of Proposed Activity
Overview
KDC has requested an IHA to authorize marine mammal take incidental
to removing and subsequently installing new piles that are necessary in
the expansion of Berth IV to accommodate larger cruise ships in the
Port of Ketchikan. Since the 2007 construction of Berth IV, the
capacity of cruise vessels and larger boats has increased where the
current Berth cannot accommodate larger and more modern vessels. This
expansion is necessary to support the local economy in Ketchikan as it
continues to grow with the cruise and tourism industries.
This proposed project entails only coastal construction activities.
Presently, several in-water structures exist that require replacement,
including floats, several groups of older piles (referred to as a
``dolphin'') (consisting of several different sized piles), float
restraints, and catwalks that connect the dolphins. These structures
would all be removed at Berth IV and new permanent structures would be
installed, including new dolphins (of varying pile sizes), a new
pontoon, a new boat float, a new ladder/platform to allow access to
dolphins, and new mooring points to aid in the expanded boat capacity
of the Berth.
Given the use of vibratory pile driving, impact pile driving, and
DTH drilling, there is the potential for marine mammals to be taken by
Level A harassment and/or Level B harassment.
Dates and Duration
The proposed IHA would be valid for the statutory maximum of 1 year
from the date of effectiveness. It will become effective upon written
notification from the applicant to NMFS, but not beginning later than 1
year from the date of issuance or extending beyond 2 years from the
date of issuance. Currently, construction is planned to occur starting
on January 2, 2026 and continue for 3 to 4 months (ending sometime
around May 2026). Pile removal and installation activities are expected
to necessitate approximately 305 hours over 64 (not necessarily
consecutive) days. Overall, the proposed project is not expected to
last more than 6 months as the current project schedule does consider
the mobilization of materials and any potential delays to do the
delayed delivery of necessary materials, equipment maintenance,
inclement weather, and shutdowns necessary to prevent impacts to any
protected species.
Specific Geographic Region
The proposed project is located within the City of Ketchikan
(Township 75 south, Range 90 east, Section 25 of the Copper River
Meridian, U.S. Geological Survey Quadrangle KET B5),
[[Page 46836]]
which is found in Southeast Alaska on the western coast of
Revillagigedo Island, near the southernmost boundary of Alaska
(Latitude: 55.344[deg]; Longitude:-131.656[deg]). Ketchikan encompasses
approximately 3 square miles (mi\2\ (7.7 square kilometers (km\2\))) of
land and 1 mi\2\ (2.6 km\2\) of water. The site is located on the east
side of Tongass Narrows, a marine channel between Revillagigedo and
Gravina Islands, consisting of a long, narrow water body approximately
11 miles (mi (17.7 kilometers (km))) (see figure 1). Ketchikan itself
is a small commercial fishing hub, tourist destination, and the
headquarters of the Tongass National Forest. The resident population is
estimated at 13,948 citizens, per the United States 2020 decennial
census. Berth IV is part of the Port of Ketchikan, an active marine
commercial and industrial area, and is located adjacent to downtown
Ketchikan on the shore of east Tongass Narrows.
Per the Ketchikan Marine Industry Council, the project site has an
approximate mean low low water (MLLW) depth ranging from -40 ft (-12.2
m) to -100 feet (-30.5 m). Tidal currents generally range from 0.3 mi
(0.5 km) to 1.6 mi (2.6 km) per hour during flood and ebb tides. At the
project site where piles would be driven, water depths range between
approximately 60 feet (ft) (18.3 meters (m)) to 160 ft (48.8 m)
(Peratrovich and Nottingham Engineers, Inc. (PND), 2006). Tidal
currents generally range from 0.3 miles (0.5 km) to 1.6 miles (2.6 km)
per hour during flood and ebb tides (PND, 2006). Water depths in
Tongass Narrows that would be ensonified are generally 160 ft (48.8 m)
or shallower, but they get deeper past the southern end of Pennock
Island, reaching depths up to 625 ft (190.5 m) (NOAA, 2015). Major
waterbodies near the area include the Clarence Strait to the north, the
Revillagigedo Channel to the south, Nichols Passage to the west, and
George Inlet to the east. Berth IV's expansion would take place at the
existing dock facility.
[GRAPHIC] [TIFF OMITTED] TN30SE25.000
[[Page 46837]]
Detailed Description of the Specified Activity
KDC has proposed to remove and subsequently install piles on the
existing Berth IV to expand its capabilities for larger cruise vessels.
All piles would be removed, temporarily installed and then subsequently
removed, or permanently installed using vibratory pile driving (ICE
44B), impact pile driving (Delmag D46), or using DTH (Holte 100,000
feet-pounds (ft-lbs.) top drive with a DTH hammer and bit). Piles would
also be ``stabbed'' using the crane to position them on the substrate
prior to installation. Specifically, the proposed project would require
the removal of the following in-water components:
The existing barge float;
The existing north float;
The existing 60-ft (18.3-m) gangway to the north float;
The floating barge dolphin #1 (consisting of two 30-inch
(in (76.2-centimeter (cm))) piles and one 36-in (91.4-cm) pile);
The floating barge dolphin #2 (consisting of two 30-in
(76.2-cm) piles);
The breasting dolphin #2 (consisting of three 36-in (91.4-
cm) piles and two 30-in (76.2-cm) piles);
The small float restraint (consisting of two 24-in (61-cm)
piles); and
The existing catwalk that connects breasting dolphin #2
and breasting dolphin #1.
In their place, new piles and in-water structures would be
installed, including:
The mooring dolphin #1 (consisting of four 36-in (91.4-cm)
steel batter piles);
The shoreline dolphin #2 (consisting of two 48-in (121.9-
cm) steel batter piles and two 48-in (121.9-cm) steel plumb piles);
The pontoon dolphin #1 (consisting of two 48-in (121.9-cm)
steel batter piles and three 48-in (121.9-cm) steel plumb piles);
The pontoon dolphin #2 (consisting of two 48-in (121.9-cm)
steel batter piles, and three 48-in (121.9-cm) steel plumb piles);
One 50-ft x 285-ft (15.2-m x 86.9-m) floating pontoon; and
One 12-ft x 220-ft (3.7-m x 67.1-m) small boat float.
Between the removal of the existing piles and the installation of
new piles, KDC would also need to temporarily install and remove piles
using vibratory pile driving for both installation and removal. These
would consist of 20 30-inch (76.2-cm) steel piles installed and removed
across approximately 10 days (5 days for installation, 5 days for
removal). These are necessary to guide and accurately place the pile
templates ahead of the installation of permanent piles.
Section 1.2.4.7 of the application includes the detailed
construction sequence, which NMFS refers to but does not reiterate
here.
Additionally, KDC would also install several out of water
components, including a ladder/platform to allow for access to the
existing breasting dolphin and two new mooring points on each of the
existing mooring dolphins #1 and #2 (n=4).
For these construction activities, KDC would utilize several barges
for the in-water activities. Two or three material barges (measuring
approximately 250 ft x 76 ft x 15.5 ft (76.2 m x 23.2 m x 4.7 m)) would
be used to transport materials from Seattle, Washington to the project
site and then to be used on-site as a staging area during construction
activities. Traveling from Juneau, Alaska to Ketchikan, one
construction barge (either the Brightwater or the Swiftwater), which
are both crane barges measuring approximately 280 ft x 76 ft x 16 ft
(85.3 m x 23.1 m x 4.9 m) or 230 ft x 60 ft x 15.5 ft (70.1 m x 18.3 m
x 4.7 m), respectively, would be located onsite to support
construction. Lastly, two 20-ft (6.1-m) skiffs, each with a single 90
horsepower (67,113 watts) onboard motor, would be transported to the
project site on either the Brightwater or the Swiftwater to support
construction, transport the crew and workers, and to support marine
mammal monitoring efforts. At the construction site, all barges would
be secured in place in-water and on-shore, either using spuds or four
15,500-pound (lbs (7,030 kilogram (kg))) anchors. The two on-shore
anchors would be placed near the existing rip rap slope while the two
in-water anchors would be places about 1,500 to 2,000 m (4,921.3 to
6,561.7 ft) from the mooring dolphins. When transiting, all vessels
would travel under 8 knots (8 nautical miles per hour), depending on
the type of vessel.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. NMFS
fully considered all of this information, and we refer the reader to
these descriptions, instead of reprinting the information. Additional
information regarding population trends and threats may be found in
NMFS' Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and
more general information about these species (e.g., physical and
behavioral descriptions) may be found on NMFS' website (https://www.fisheries.noaa.gov/find-species).
Table 2 lists all species or stocks for which take is expected and
proposed to be authorized for this activity and summarizes information
related to the population or stock, including regulatory status under
the MMPA and Endangered Species Act (ESA) and potential biological
removal (PBR), where known. PBR is defined by the MMPA as the maximum
number of animals, not including natural mortalities, that may be
removed from a marine mammal stock while allowing that stock to reach
or maintain its optimum sustainable population (as described in NMFS'
SARs). While no serious injury or mortality is anticipated or proposed
to be authorized here, PBR and annual serious injury and mortality (M/
SI) from anthropogenic sources are included here as gross indicators of
the status of the species or stocks and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' draft 2024 Alaska and Pacific SARs. All values presented in table
2 are the most recent available at the time of publication (including
from the draft 2024 SARs) and are available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.
[[Page 46838]]
Table 2--Species \a\ With Estimated Take From the Specified Activities
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ESA/ MMPA status; Stock abundance (CV;
Common name Scientific name Stock strategic (Y/N) Nmin; most recent PBR Annual M/
\b\ abundance survey) \c\ SI \d\
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Order Artiodactyla--Infraorder Cetacea--Mysticeti (baleen whales)
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Family Balaenopteridae (rorquals):
Humpback whale.................. Megaptera novaeangliae. Hawai[revaps]i \e\..... -,-,N 11,278 (0.56, 7,265, 127 27.09
2020).
Mexico-North Pacific... T, D, Y N/A (N/A, N/A, 2006) UND 0.57
\f\.
Minke whale..................... Balaenoptera Alaska................. -,-,N N/A (N/A, N/A, N/A) UND 0
acutorostrata. \g\.
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Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
Killer whale.................... Orcinus orca........... Eastern North Pacific -,-,N 1,920, (N/A, 1,920, 19 1.3
Alaska Resident. 2019) \h\.
Eastern North Pacific -,-,N 302 (N/A, 302, 2018).. 2.2 0.2
Northern Resident.
West Coast Transient... -,-,N 439 (N/A, 349, 2018).. 3.5 0.4
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Family Phocoenidae (porpoises):
Dall's porpoise................. Phocoenoides dalli..... Alaska................. -,-,N UND (UND, UND, 2015) UND 37
\i\.
Harbor porpoise................. Phocoena phocoena...... Southern Southeast -,-,Y 890 (0.37, 610, 2019). 6.1 7.4
Alaska Inland Waters
\j\.
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Order--Carnivora--Pinnipedia
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Family Otariidae (eared seals and
sea lions)
Steller sea lion................ Eumetopias jubatus..... Eastern................ -,-,N 36,308 (N/A, 36,308, 2,178 93.2
2022) \k\.
Family Phocidae (earless seals)
Harbor seal..................... Phoca vitulina......... Clarence Strait........ -,-,N 27,659 (N/A, 24,854, 746 40
2015).
Northern elephant seal.......... Mirounga angustirostris CA Breeding............ -,-,N 187,386 (N/A, 85,369, 5,122 13.7
2013).
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\a\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
(https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/).
\b\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T); MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under
the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\c\ NMFS marine mammal stock assessment reports online at www.nmfs.noaa.gov/pr/sars/. CV is the coefficient of variation; Nmin is the minimum estimate
of stock abundance. In some cases, a CV is not applicable. N/A indicates data are unknown. UND (undetermined) PBR indicates data are available to
calculate a PBR level but a determination has been made that calculating a PBR level using those data is inappropriate (see the SAR for details).
\d\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, ship strikes). Annual M/SI often cannot be determined precisely and is sometimes presented as a minimum value or range. A CV
associated with estimated mortality due to commercial fisheries is presented in some cases.
\e\ New SAR in 2022 following North Pacific humpback whale stock structure changes.
\f\ Abundance estimates are based upon data collected more than 8 years ago and, therefore, current estimates are considered unknown.
\g\ Reliable population estimates are not available for this stock. Please see Friday et al. (2013) and Zerbini et al. (2006) for additional information
on numbers of minke whales in Alaska.
\h\ Nest, or the best estimate of abundance, is based upon counts of individuals identified from photo-ID catalogs.
\i\ The best available abundance estimate is likely an underestimate for the entire stock because it is based upon a survey that covered only a small
portion of the stock's range.
\j\ New stock split from Southeast Alaska stock.
\k\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates provided are for the U.S.
only.
As indicated above, all eight species (with 11 managed stocks) in
table 2 temporally and spatially co-occur with the activity to the
degree that take is reasonably likely to occur.
For all species except humpback whales, there are no known
biologically important areas (BIA) near the project site that KDC's
proposed activity would impact. For humpback whales, the inland waters
of Southeast Alaska are a seasonal feeding BIA from May through
September (Wild et al., 2023). However, due to development and human
presence, the Tongass Narrows are not essential portions of this
habitat. The Tongass Narrows are also a small passageway representing a
tiny portion of the available habitat for humpback whales.
In addition, sea otters (Enhydra lutris) may be found in both
Ketchikan and the Tongass Narrows. However, this species is managed by
the U.S. Fish and Wildlife Service (see https://www.fws.gov/species/sea-otter-enhydra-lutris) and therefore not discussed further in this
document.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Not all marine mammal species have equal
hearing capabilities or hear over the same frequency range (e.g.,
Richardson et al., 1995; Wartzok and Ketten, 1999; Au and Hastings,
2008). To reflect this, Southall et al. (2007, 2019) recommended that
marine mammals be divided into hearing groups based on directly
measured (behavioral or auditory evoked potential techniques) or
estimated hearing ranges (behavioral response data, anatomical
modeling, etc.). Subsequently, NMFS (2018, 2024) described generalized
hearing ranges for these marine mammal hearing groups. Generalized
hearing ranges were chosen based on the approximately 65-decibel (dB)
threshold
[[Page 46839]]
from the normalized composite audiograms, with the exception for lower
limits for low-frequency cetaceans where the lower bound was deemed to
be biologically implausible and the lower bound from Southall et al.
(2007) retained. On May 3, 2024, NMFS published (89 FR 36762) and
solicited public comment on its draft Updated Technical Guidance, which
includes updated thresholds and weighting functions to inform auditory
injury estimates, and is intended to replace the 2018 Technical
Guidance referenced above, once finalized. The public comment period
ended on June 17, 2024, and although the Guidance is not final, we
expect the Guidance to represent the best available science once it is.
In order to support consideration of the best available science, we
have conducted basic comparative calculations using the draft Guidance
for the purposes of understanding the number of takes by Level A
harassment under the updated Guidance. Marine mammal hearing groups and
their associated hearing ranges are provided in table 3. Of the species
potentially present in the action area, two are considered low-
frequency (LF) cetaceans, one is considered high-frequency (HF)
cetaceans, two are considered very high-frequency (VHF) cetaceans, one
is an otariid pinniped (OW), and two are phocid pinnipeds (PW).
Table 3--Marine Mammal Hearing Groups
[NMFS, 2024]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 36 kHz.
whales).
High-frequency (HF) cetaceans (dolphins, 150 Hz to 160 kHz.
toothed whales, beaked whales, bottlenose
whales).
Very High-frequency (VHF) cetaceans (true 200 Hz to 165 kHz.
porpoises, Kogia, river dolphins,
Cephalorhynchid, Lagenorhynchus cruciger &
L. australis).
Phocid pinnipeds (PW) (underwater) (true 40 Hz to 90 kHz.
seals).
Otariid pinnipeds (OW) (underwater) (sea 60 Hz to 68 kHz.
lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges may not be as broad. Generalized hearing range
chosen based on ~65 dB threshold from composite audiogram, previous
analysis in NMFS (2018), and/or data from Southall et al. (2007,
2019). Additionally, animals are able to detect very loud sounds above
and below that ``generalized'' hearing range.
For more detail concerning these groups and associated generalized
hearing ranges, please see NMFS (2024) for a review of available
information.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section includes a summary and provides a discussion of the
ways in which components of the specified activity may impact marine
mammals and their habitat. The Estimated Take of Marine Mammals section
later in this document includes a quantitative analysis of the number
of individuals that are expected to be taken by this activity. The
Negligible Impact Analysis and Determination section considers the
content of this section, the Estimated Take of Marine Mammals section,
and the Proposed Mitigation section, to draw conclusions regarding the
likely impacts of these activities on the reproductive success or
survivorship of individuals and whether those impacts are reasonably
expected to, or reasonably likely to, adversely affect the species or
stock through effects on annual rates of recruitment or survival.
Acoustic effects on marine mammals during the specified activities
are expected to potentially occur from impact and vibratory pile
removal and/or installation, and DTH. The effects of underwater noise
from KDC's proposed activities have the potential to result in Level B
harassment of marine mammals in the action area, and for some marine
mammal species as a result of certain activities, Level A harassment.
Overall, the proposed activities include the removal and
installation of old, temporary, and permanent piles in Ketchikan,
Alaska. There are a variety of types and degrees of effects to marine
mammals, prey species, and habitat that could occur as a result of the
Project. Below we provide a brief description of the types of sound
sources that would be generated by the project, the general impacts
from these types of activities, and an analysis of the anticipated
impacts on marine mammals from the project, with consideration of the
proposed mitigation measures.
Description of Sound Sources for the Specified Activities
Activities associated with the proposed project that have the
potential to incidentally take marine mammals through exposure to sound
would include impact pile driving for installation, vibratory pile
driving for removal and installation, and DTH. Impact hammers typically
operate by repeatedly dropping and/or pushing a heavy piston onto a
pile to drive the pile into the substrate. Sound generated by impact
hammers is impulsive, characterized by rapid rise times and high peak
levels, a potentially injurious combination (Hastings and Popper,
2005). Vibratory hammers install piles by vibrating them and allowing
the weight of the hammer to push them into the substrate. Vibratory
hammers typically produce less sound (i.e., lower levels) than impact
hammers. Peak sound pressure levels (SPLs) may be 180 dB or greater but
are generally 10 to 20 dB lower than SPLs generated during impact pile
driving of the same-sized pile (Oestman et al., 2009; California
Department of Transportation (CALTRANS), 2015, 2020). Sounds produced
by vibratory hammers are non-impulsive; compared to sounds produced by
impact hammers, the rise time is slower, reducing the probability and
severity of injury, and the sound energy is distributed over more time
(Nedwell and Edwards, 2002; Carlson et al., 2005).
DTH systems use a combination of percussive and drilling mechanisms
to advance a hole into the rock, with or without simultaneously
advancing a pile/casing into that hole. Drill cuttings and debris at
the rock face are removed by an air-lift exhaust through the inside of
the pile (Guan and Miner, 2020). Unlike other pile installation
methods, at least one sound source during DTH is found at the
intersection of the drill tip and the substrate and is often more
characteristically a point source rather than a linear source, as in
impact and vibratory pile driving. A DTH system is essentially a drill
bit that drills through the bedrock using a rotating function like a
normal drill, in concert with a hammering mechanism integrated into the
DTH hammer to increase speed of progress through the substrate (i.e.,
it is similar to a ``hammer drill'' hand tool). DTH systems typically
involve a single hammer (mono-hammer), but multi- or ``cluster'' hammer
drills may also be used.
DTH systems include both DTH drilling and DTH driving techniques.
[[Page 46840]]
During DTH pile drilling, the DTH hammer does not make direct contact
with the pile; rather the hammer acts as a percussive drill to advance
a hole through the substrate within a casing (casing is driven through
overburden using impact or vibratory methods). After the hole is
drilled to the desired depth, the casing is removed, and the production
pile is placed inside the hole. Often, the production pile is then
proofed with an impact hammer. If needed, a tension anchor can be
drilled following these same methods within the production pile to add
lateral support to the pile.
During DTH pile driving, the DTH hammer directly strikes a
specially designed shoe located at the bottom of the pile, which has
wings that have a slightly larger diameter than the pile (i.e., the
hammer directly strikes the production pile itself; no pile casing is
used). The drill head locks into the bottom of the pile, and then the
drill head and pile advance simultaneously into the substrate to the
desired depth. Often, the production pile is then proofed with an
impact hammer. If needed, a tension anchor can be drilled using DTH
drilling methods within the production pile to add lateral support to
the pile.
The sounds produced by the DTH methods simultaneously contain both
a continuous non-impulsive component from the drilling action and an
impulsive component from the hammering effect. Therefore, for purposes
of evaluating Level A and Level B harassment under the MMPA, NMFS
treats DTH systems as both impulsive (Level A harassment thresholds)
and continuous, non-impulsive (Level B harassment thresholds) sound
source types simultaneously.
Typical activities for which DTH systems are used include rock
socketing and tension or rock anchoring. Rock socketing involves using
DTH techniques to create a hole in the bedrock inside which a pile is
placed to give it lateral and longitudinal strength as described in DTH
drilling, above. Rock sockets are made in bedrock when overlaying
sediments are too shallow to adequately secure the bottom portion of a
pile using other methods.
The purpose of a tension anchor is to secure a pile to the bedrock
to withstand uplift forces. Tension anchors are installed within
production piles that are installed into the substrate below the
elevation of the pile tip after the pile has been driven through the
sediment layer to refusal. Typically a small diameter casing (e.g., 6-
in to 8-in (15.24-cm to 20.32-cm)) steel pipe casing) is inserted into
a larger diameter production pile. A rock drill is then inserted into
the casing, and a small (e.g., 6- to 10-in; 15.24- to 25.4-cm) diameter
hole is drilled into bedrock with rotary and percussion drilling
methods (using DTH drilling methods). The drilling activity is
contained within the steel pile casing and the steel pipe pile. The
typical depth of the drilled tension anchor hole varies, but 6-9 m
(19.7-29.5 ft) depth is common. A steel rod is then grouted into the
drilled hole and affixed to the top of the pile.
The likely or possible impacts of KDC's proposed activities on
marine mammals could involve both non-acoustic and acoustic stressors.
Potential non-acoustic stressors could result from the physical
presence of the equipment and personnel; however, given there are no
known pinniped haul-out sites in the vicinity of the project site,
visual and other non-acoustic stressors would be limited, and any
impacts to marine mammals are expected to primarily be acoustic in
nature.
Potential Effects of Underwater Sound on Marine Mammals
The introduction of anthropogenic noise into the aquatic
environment from vibratory pile driving, impact pile driving, and DTH
is the primary means by which marine mammals may be harassed from the
KDC's specified activities. Anthropogenic sounds cover a broad range of
frequencies and sound levels and can have a range of highly variable
impacts on marine life from none or minor to potentially severe
responses depending on received levels, duration of exposure,
behavioral context, and various other factors. Broadly, underwater
sound from active acoustic sources, such as those in the proposed
project, can potentially result in one or more of the following:
temporary or permanent hearing impairment, non-auditory physical or
physiological effects, behavioral disturbance, stress, and masking
(Richardson et al., 1995; Gordon et al., 2003; Nowacek et al., 2007;
Southall et al., 2007; G[ouml]tz et al., 2009).
We describe the more severe effects of certain non-auditory
physical or physiological effects only briefly as we do not expect that
the use of impact/vibratory hammers and DTH are reasonably likely to
result in such effects (see below for further discussion). Potential
effects from impulsive sound sources can range in severity from effects
such as behavioral disturbance or tactile perception to physical
discomfort, slight injury of the internal organs and the auditory
system, or mortality (Yelverton et al., 1973). Non-auditory
physiological effects or injuries that theoretically might occur in
marine mammals exposed to high level underwater sound or as a secondary
effect of extreme behavioral reactions (e.g., change in dive profile as
a result of an avoidance reaction) caused by exposure to sound include
neurological effects, bubble formation, resonance effects, and other
types of organ or tissue damage (Cox et al., 2006; Southall et al.,
2007; Zimmer and Tyack, 2007; Tal et al., 2015). The Project activities
considered here do not involve the use of devices such as explosives or
mid-frequency tactical sonar that are associated with these types of
effects.
In general, animals exposed to natural or anthropogenic sound may
experience physical and psychological effects, ranging in magnitude
from none to severe (Southall et al., 2007, 2019). Exposure to
anthropogenic noise has the potential to result in auditory threshold
shifts and behavioral reactions (e.g., avoidance, temporary cessation
of foraging and vocalizing, changes in dive behavior). It can also lead
to non-observable physiological responses, such an increase in stress
hormones. Additional noise in a marine mammal's habitat can mask
acoustic cues used by marine mammals to carry out daily functions, such
as communication and predator and prey detection.
The degree of effect of an acoustic exposure on marine mammals is
dependent on several factors, including, but not limited to, sound type
(e.g., impulsive vs. non-impulsive), signal characteristics, the
species, age and sex class (e.g., adult male vs. mom with calf),
duration of exposure, the distance between the noise source and the
animal, received levels, behavioral state at time of exposure, and
previous history with exposure (Wartzok et al., 2004; Southall et al.,
2007). In general, sudden, high-intensity sounds can cause hearing
loss, as can longer exposures to lower-intensity sounds. Moreover, any
temporary or permanent loss of hearing, if it occurs at all, will occur
almost exclusively for noise within an animal's hearing range. We
describe below the specific manifestations of acoustic effects that may
occur based on the activities proposed by KDC. Richardson et al. (1995)
described zones of increasing intensity of effect that might be
expected to occur in relation to distance from a source and assuming
that the signal is within an animal's hearing range. First (at the
greatest distance) is the area within which the acoustic signal would
be audible (potentially perceived) to the animal but not strong enough
to elicit any overt
[[Page 46841]]
behavioral or physiological response. The next zone (closer to the
receiving animal) corresponds with the area where the signal is audible
to the animal and of sufficient intensity to elicit behavioral or
physiological responsiveness. The third is a zone within which, for
signals of high intensity, the received level is sufficient to
potentially cause discomfort or tissue damage to auditory or other
systems. Overlaying these zones to a certain extent is the area within
which masking (i.e., when a sound interferes with or masks the ability
of an animal to detect a signal of interest that is above the absolute
hearing threshold) may occur; the masking zone may be highly variable
in size.
Below, we provide additional detail regarding potential impacts on
marine mammals and their habitat from noise in general, starting with
hearing impairment, as well as from the specific activities KDC plans
to conduct, to the degree it is available.
Hearing Threshold Shifts--NMFS defines a noise-induced threshold
shift as a change, usually an increase, in the threshold of audibility
at a specified frequency or portion of an individual's hearing range
above a previously established reference level (NMFS, 2018, 2024). The
amount of threshold shift is customarily expressed in dB. A threshold
shift can be permanent or temporary. As described in NMFS (2018, 2024)
there are numerous factors to consider when examining the consequence
of threshold shift, including, but not limited to, the signal temporal
pattern (e.g., impulsive or non-impulsive), likelihood an individual
would be exposed for a long enough duration or to a high enough level
to induce a threshold shift, the magnitude of the threshold shift, time
to recovery (seconds to minutes or hours to days), the frequency range
of the exposure (i.e., spectral content), the hearing frequency range
of the exposed species relative to the signal's frequency spectrum
(i.e., how animal uses sound within the frequency band of the signal;
e.g., Kastelein et al., 2014), and the overlap between the animal and
the source (e.g., spatial, temporal, and spectral).
Auditory Injury (AUD INJ)--NMFS (2024) defines AUD INJ as damage to
the inner ear that can result in destruction of tissue, such as the
loss of cochlear neuron synapses or auditory neuropathy (Houser, 2021;
Finneran, 2024). AUD INJ may or may not result in a permanent threshold
shift (PTS). PTS is subsequently defined as a permanent, irreversible
increase in the threshold of audibility at a specified frequency or
portion of an individual's hearing range above a previously established
reference level (NMFS, 2024). PTS does not generally affect more than a
limited frequency range, and an animal that has incurred PTS has some
level of hearing loss at the relevant frequencies; typically animals
with PTS or other AUD INJ are not functionally deaf (Au and Hastings,
2008; Finneran, 2016). Available data from humans and other terrestrial
mammals indicate that a 40-dB threshold shift approximates AUD INJ
onset (see Ward et al., 1958, 1959; Ward, 1960; Kryter et al., 1966;
Miller, 1974; Ahroon et al., 1996; Henderson et al., 2008). AUD INJ
levels for marine mammals are estimates, as with the exception of a
single study unintentionally inducing PTS in a harbor seal (Phoca
vitulina) (Kastak et al., 2008), there are no empirical data measuring
AUD INJ in marine mammals largely due to the fact that, for various
ethical reasons, experiments involving anthropogenic noise exposure at
levels inducing AUD INJ are not typically pursued or authorized (NMFS,
2024).
Temporary Threshold Shift (TTS)--TTS is a temporary, reversible
increase in the threshold of audibility at a specified frequency or
portion of an individual's hearing range above a previously established
reference level (NMFS, 2024), and is not considered an AUD INJ. Based
on data from marine mammal TTS measurements (see Southall et al., 2007,
2019), a TTS of 6 dB is considered the minimum threshold shift clearly
larger than any day-to-day or session-to-session variation in a
subject's normal hearing ability (Finneran et al., 2000, 2002; Schlundt
et al., 2000). As described in Finneran (2015), marine mammal studies
have shown the amount of TTS increases with the 24-hour cumulative
sound exposure level (SEL24) in an accelerating fashion: at
low exposures with lower SEL24, the amount of TTS is
typically small and the growth curves have shallow slopes. At exposures
with higher SEL24, the growth curves become steeper and
approach linear relationships with the sound exposure level (SEL).
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to more impactful (similar to those discussed in
auditory masking, below). For example, a marine mammal may be able to
readily compensate for a brief, relatively small amount of TTS in a
non-critical frequency range that takes place during a time when the
animal is traveling through the open ocean, where ambient noise is
lower and there are not as many competing sounds present.
Alternatively, a larger amount and longer duration of TTS sustained
during time when communication is critical for successful mother/calf
interactions could have more severe impacts. We note that reduced
hearing sensitivity as a simple function of aging has been observed in
marine mammals, as well as humans and other taxa (Southall et al.,
2007), so we can infer that strategies exist for coping with this
condition to some degree, though likely not without cost.
Many studies have examined noise-induced hearing loss in marine
mammals (see Finneran (2015) and Southall et al. (2019) for summaries).
TTS is the mildest form of hearing impairment that can occur during
exposure to sound (Kryter, 2013). While experiencing TTS, the hearing
threshold rises, and a sound must be at a higher level in order to be
heard. In terrestrial and marine mammals, TTS can last from minutes or
hours to days (in cases of strong TTS). In many cases, hearing
sensitivity recovers rapidly after exposure to the sound ends. For
cetaceans, published data on the onset of TTS are limited to captive
bottlenose dolphin (Tursiops truncatus), beluga whale (Delphinapterus
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena
asiaeorientalis) (Southall et al., 2019). For pinnipeds in water,
measurements of TTS are limited to harbor seals, elephant seals,
bearded seals (Erignathus barbatus) and California sea lions (Zalophus
californianus) (Kastak et al., 1999, 2007; Kastelein et al., 2019b,
2019c, 2021, 2022a, 2022b; Reichmuth et al., 2019; Sills et al., 2020).
TTS was not observed in spotted (Phoca largha) and ringed (Pusa
hispida) seals exposed to single airgun impulse sounds at levels
matching previous predictions of TTS onset (Reichmuth et al., 2016).
These studies examine hearing thresholds measured in marine mammals
before and after exposure to intense or long-duration sound exposures.
The difference between the pre-exposure and post-exposure thresholds
can be used to determine the amount of threshold shift at various post-
exposure times.
The amount and onset of TTS depends on the exposure frequency.
Sounds below the region of best sensitivity for a species or hearing
group are less hazardous than those near the region of best sensitivity
(Finneran and Schlundt, 2013). At low frequencies, onset-TTS exposure
levels are higher compared to those in the region of best sensitivity
(i.e., a low frequency noise
[[Page 46842]]
would need to be louder to cause TTS onset when TTS exposure level is
higher), as shown for harbor porpoises and harbor seals (Kastelein et
al., 2019a, 2019c). Note that in general, harbor seals and harbor
porpoises have a lower TTS onset than other measured pinniped or
cetacean species (Finneran, 2015). In addition, TTS can accumulate
across multiple exposures, but the resulting TTS will be less than the
TTS from a single, continuous exposure with the same SEL (Mooney et
al., 2009; Finneran et al., 2010; Kastelein et al., 2014, 2015). This
means that TTS predictions based on the total, SEL24 will
overestimate the amount of TTS from intermittent exposures, such as
sonars and impulsive sources. Nachtigall et al. (2018) describe
measurements of hearing sensitivity of multiple odontocete species
(bottlenose dolphin, harbor porpoise, beluga, and false killer whale
(Pseudorca crassidens)) when a relatively loud sound was preceded by a
warning sound. These captive animals were shown to reduce hearing
sensitivity when warned of an impending intense sound. Based on these
experimental observations of captive animals, the authors suggest that
wild animals may dampen their hearing during prolonged exposures or if
conditioned to anticipate intense sounds. Another study showed that
echolocating animals (including odontocetes) might have anatomical
specializations that might allow for conditioned hearing reduction and
filtering of low-frequency ambient noise, including increased stiffness
and control of middle ear structures and placement of inner ear
structures (Ketten et al., 2021). Data available on noise-induced
hearing loss for mysticetes are currently lacking (NMFS, 2024).
Additionally, the existing marine mammal TTS data come from a limited
number of individuals within these species.
Relationships between TTS and AUD INJ thresholds have not been
studied in marine mammals, and there are no measured PTS data for
cetaceans, but such relationships are assumed to be similar to those in
humans and other terrestrial mammals. AUD INJ typically occurs at
exposure levels at least several dB above that inducing mild TTS (e.g.,
a 40-dB threshold shift approximates AUD INJ onset (Kryter et al.,
1966; Miller, 1974), while a 6-dB threshold shift approximates TTS
onset (Southall et al., 2007, 2019). Based on data from terrestrial
mammals, a precautionary assumption is that the AUD INJ thresholds for
impulsive sounds (such as impact pile driving pulses as received close
to the source) are at least 6 dB higher than the TTS threshold on a
peak-pressure basis and AUD INJ cumulative sound exposure level
thresholds are 15 to 20 dB higher than TTS cumulative sound exposure
level thresholds (Southall et al., 2007, 2019). Given the higher level
of sound or longer exposure duration necessary to cause AUD INJ as
compared with TTS, it is considerably less likely that AUD INJ could
occur.
Behavioral Effects--Exposure to noise also has the potential to
behaviorally disturb marine mammals response--in other words, not every
response qualifies as behavioral disturbance, and for responses that
do, those of a higher level, or accrued across a longer duration, have
the potential to affect foraging, reproduction, or survival. Behavioral
disturbance may include a variety of effects, including subtle changes
in behavior (e.g., minor or brief avoidance of an area or changes in
vocalizations), more conspicuous changes in similar behavioral
activities, and more sustained and/or potentially severe reactions,
such as displacement from or abandonment of high-quality habitat.
Behavioral responses may include: changing durations of surfacing and
dives, changing direction and/or speed; reducing/increasing vocal
activities; changing/cessation of certain behavioral activities (such
as socializing or feeding); eliciting a visible startle response or
aggressive behavior (such as tail/fin slapping or jaw clapping); and
avoidance of areas where sound sources are located. In addition,
pinnipeds may increase their haul out time, possibly to avoid in-water
disturbance (Thorson and Reyff, 2006).
Behavioral responses to sound are highly variable and context-
specific and any reactions depend on numerous intrinsic and extrinsic
factors (e.g., species, state of maturity, experience, current
activity, reproductive state, auditory sensitivity, time of day), as
well as the interplay between factors (e.g., Richardson et al., 1995;
Wartzok et al., 2004; Southall et al., 2007, 2019; Weilgart, 2007;
Archer et al., 2010). Behavioral reactions can vary not only among
individuals but also within an individual, depending on previous
experience with a sound source, context, and numerous other factors
(Ellison et al., 2012), and can vary depending on characteristics
associated with the sound source (e.g., whether it is moving or
stationary, number of sources, distance from the source). In general,
pinnipeds seem more tolerant of, or at least habituate more quickly to,
potentially disturbing underwater sound than do cetaceans, and
generally seem to be less responsive to exposure to industrial sound
than most cetaceans. Please see Appendices B and C of Southall et al.
(2007) and Gomez et al. (2016) for reviews of studies involving marine
mammal behavioral responses to sound.
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2004). Animals are most likely to habituate to
sounds that are predictable and unvarying. It is important to note that
habituation is appropriately considered as a ``progressive reduction in
response to stimuli that are perceived as neither aversive nor
beneficial,'' rather than as, more generally, moderation in response to
human disturbance (Bejder et al., 2009). The opposite process is
sensitization, when an unpleasant experience leads to subsequent
responses, often in the form of avoidance, at a lower level of
exposure.
As noted above, behavioral state may affect the type of response.
For example, animals that are resting may show greater behavioral
change in response to disturbing sound levels than animals that are
highly motivated to remain in an area for feeding (Richardson et al.,
1995; Wartzok et al., 2004; National Research Council (NRC), 2005).
Controlled experiments with captive marine mammals have shown
pronounced behavioral reactions, including avoidance of loud sound
sources (Ridgway et al., 1997; Finneran et al., 2003). Observed
responses of wild marine mammals to loud-pulsed sound sources (e.g.,
seismic airguns) have been varied but often consist of avoidance
behavior or other behavioral changes (Richardson et al., 1995; Morton
and Symonds, 2002; Nowacek et al., 2007).
Available studies show wide variation in response to underwater
sound; therefore, it is difficult to predict specifically how any given
sound in a particular instance might affect marine mammals perceiving
the signal (e.g., Erbe et al., 2019). If a marine mammal does react
briefly to an underwater sound by changing its behavior or moving a
small distance, the impacts of the change are unlikely to be
significant to the individual, let alone the stock or population. If a
sound source displaces marine mammals from an important feeding or
breeding area for a prolonged period, impacts on individuals and
populations could be significant (e.g., Lusseau and Bejder, 2007;
Weilgart, 2007; NRC, 2005). However, there are broad categories of
potential response, which we describe in greater detail here, that
include alteration of dive behavior,
[[Page 46843]]
alteration of foraging behavior, effects to breathing, interference
with or alteration of vocalization, avoidance, and flight.
Avoidance and displacement--Changes in dive behavior can vary
widely and may consist of increased or decreased dive times and surface
intervals as well as changes in the rates of ascent and descent during
a dive (e.g., Frankel and Clark, 2000; Costa et al., 2003; Ng and
Leung, 2003; Nowacek et al., 2004; Goldbogen et al., 2013a, 2013b,
Blair et al., 2016). Variations in dive behavior may reflect
interruptions in biologically significant activities (e.g., foraging)
or they may be of little biological significance. The impact of an
alteration to dive behavior resulting from an acoustic exposure depends
on what the animal is doing at the time of the exposure and the type
and magnitude of the response.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. Acoustic and movement bio-logging tools also have been used
in some cases to infer responses to anthropogenic noise. For example,
Blair et al. (2015) reported significant effects on humpback whale
foraging behavior in Stellwagen Bank in response to ship noise
including slower descent rates, and fewer side-rolling events per dive
with increasing ship nose. In addition, Wisniewska et al. (2018)
reported that tagged harbor porpoises demonstrated fewer prey capture
attempts when encountering occasional high-noise levels resulting from
vessel noise as well as more vigorous fluking, interrupted foraging,
and cessation of echolocation signals observed in response to some
high-noise vessel passes. As for other types of behavioral response,
the frequency, duration, and temporal pattern of signal presentation,
as well as differences in species sensitivity, are likely contributing
factors to differences in response in any given circumstance (e.g.,
Croll et al., 2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko
et al., 2007). A determination of whether foraging disruptions incur
fitness consequences would require information on or estimates of the
energetic requirements of the affected individuals and the relationship
between prey availability, foraging effort and success, and the life
history stage of the animal.
Respiration rates vary naturally with different behaviors and
alterations to breathing rate as a function of acoustic exposure can be
expected to co-occur with other behavioral reactions, such as a flight
response or an alteration in diving. However, respiration rates in and
of themselves may be representative of annoyance or an acute stress
response. Various studies have shown that respiration rates may either
be unaffected or could increase, depending on the species and signal
characteristics, again highlighting the importance in understanding
species differences in the tolerance of underwater noise when
determining the potential for impacts resulting from anthropogenic
sound exposure (e.g., Kastelein et al., 2001; 2005; 2006; Gailey et
al., 2007). For example, harbor porpoise respiration rates increased in
response to pile driving sounds at and above a received broadband SPL
of 136 dB (zero-peak SPL: 151 dB re 1 [mu]Pa (decibels referenced to 1
microPascal ([micro]Pa)); SEL of a single strike (SELss):
127 dB re 1 [mu]Pa\2\-s) (Kastelein et al., 2013).
Avoidance is the displacement of an individual from an area or
migration path as a result of the presence of a sound or other
stressors, and is one of the most obvious manifestations of disturbance
in marine mammals (Richardson et al., 1995). For example, gray whales
(Eschrichtius robustus) are known to change direction--deflecting from
customary migratory paths--in order to avoid noise from seismic surveys
(Malme et al., 1984). Harbor porpoises, Atlantic white-sided dolphins
(Lagenorhynchus actusus), and minke whales have demonstrated avoidance
in response to vessels during line transect surveys (Palka and Hammond,
2001). In addition, beluga whales in the St. Lawrence Estuary in Canada
have been reported to increase levels of avoidance with increased boat
presence by way of increased dive durations and swim speeds, decreased
surfacing intervals, and by bunching together into groups (Blane and
Jaakson, 1994). Avoidance may be short-term, with animals returning to
the area once the noise has ceased (e.g., Bowles et al., 1994; Goold,
1996; Stone et al., 2000; Morton and Symonds, 2002; Gailey et al.,
2007). Longer-term displacement is possible, however, which may lead to
changes in abundance or distribution patterns of the affected species
in the affected region if habituation to the presence of the sound does
not occur (e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann
et al., 2006).
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
the intensity of the response (e.g., directed movement, rate of
travel). Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus, 1996; Bowers et al., 2018). The result of a flight response
could range from brief, temporary exertion and displacement from the
area where the signal provokes flight to, in extreme cases, marine
mammal strandings (England et al., 2001). However, it should be noted
that response to a perceived predator does not necessarily invoke
flight (Ford and Reeves, 2008), and whether individuals are solitary or
in groups may influence the response.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other critical behaviors such as foraging or resting). These effects
have generally not been demonstrated for marine mammals, but studies
involving fishes and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates (e.g., Beauchamp and
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In
addition, chronic disturbance can cause population declines through
reduction of fitness (e.g., decline in body condition) and subsequent
reduction in reproductive success, survival, or both (e.g., Harrington
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However,
Ridgway et al. (2006) reported that increased vigilance in bottlenose
dolphins exposed to sound over a 5-day period did not cause any sleep
deprivation or stress effects.
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions resulting from reactions to stressors such as sound
exposure are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al., 2007).
Consequently, a behavioral response lasting less than one day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al., 2007). Note that there is a difference between multi-day
substantive (i.e., meaningful) behavioral reactions and multi-day
anthropogenic activities. For example, just because an activity lasts
for multiple days does not necessarily mean that individual animals are
either exposed to activity-related stressors for multiple days or,
[[Page 46844]]
further, exposed in a manner resulting in sustained multi-day
substantive behavioral responses.
Stress responses--An animal's perception of a threat may be
sufficient to trigger stress responses consisting of some combination
of behavioral responses, autonomic nervous system responses,
neuroendocrine responses, or immune responses (e.g., Seyle, 1950;
Moberg, 2000). In many cases, an animal's first and sometimes most
economical (in terms of energetic costs) response is behavioral
avoidance of the potential stressor. Autonomic nervous system responses
to stress typically involve changes in heart rate, blood pressure, and
gastrointestinal activity. These responses have a relatively short
duration and may or may not have a significant long-term effect on an
animal's fitness.
Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all stress-related neuroendocrine
functions that are affected by stress--including immune competence,
reproduction, metabolism, and behavior--are regulated by pituitary
hormones. Stress-induced changes in the secretion of pituitary hormones
have been implicated in failed reproduction, altered metabolism,
reduced immune competence, and behavioral disturbance (e.g., Moberg,
1987; Blecha, 2000). Increases in the circulation of glucocorticoids
are also equated with stress (Romano et al., 2004).
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and ``distress'' is the cost of
the response. During a stress response, an animal uses glycogen stores
that can be quickly replenished once the stress is alleviated. In such
circumstances, the cost of the stress response would not pose serious
fitness consequences. However, when an animal does not have sufficient
energy reserves to satisfy the energetic costs of a stress response,
energy resources must be diverted from other functions. This state of
distress would last until the animal replenishes its energetic reserves
sufficient to restore normal function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well studied through
controlled experiments and for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al., 2005; Ayres et al., 2012; Yang
et al., 2022). Stress responses due to exposure to anthropogenic sounds
or other stressors and their effects on marine mammals have also been
reviewed (Fair and Becker, 2000; Romano et al., 2002b) and, more
rarely, studied in wild populations (e.g., Romano et al., 2002a). For
example, Rolland et al. (2012) found that noise reduction from reduced
ship traffic in the Bay of Fundy was associated with decreased stress
in North Atlantic right whales. In addition, Lemos et al. (2022)
observed a correlation between higher levels of fecal glucocorticoid
metabolite concentrations (indicative of a stress response) and vessel
traffic in gray whales. Yang et al. (2022) studied behavioral and
physiological responses in captive bottlenose dolphins exposed to
playbacks of ``pile-driving-like'' impulsive sounds, finding
significant changes in cortisol and other physiological indicators but
only minor behavioral changes. These and other studies lead to a
reasonable expectation that some marine mammals would experience
physiological stress responses upon exposure to acoustic stressors and
that it is possible that some of these would be classified as
``distress.'' In addition, any animal experiencing TTS would likely
also experience stress responses (NRC, 2003, 2005); however, distress
is an unlikely result of this project based on observations of marine
mammals during previous, similar construction projects.
Vocalizations and Auditory Masking--Since many marine mammals rely
on sound to find prey, moderate social interactions, and facilitate
mating (Tyack, 2008), noise from anthropogenic sound sources can
interfere with these functions, but only if the noise spectrum overlaps
with the hearing sensitivity of the receiving marine mammal (Southall
et al., 2007; Clark et al., 2009; Hatch et al., 2012). Chronic exposure
to excessive, though not high-intensity, noise could cause masking at
particular frequencies for marine mammals that utilize sound for vital
biological functions (Clark et al., 2009). Acoustic masking is when
other noises such as from human sources interfere with an animal's
ability to detect, recognize, or discriminate between acoustic signals
of interest (e.g., those used for intraspecific communication and
social interactions, prey detection, predator avoidance, navigation)
(Richardson et al., 1995; Erbe et al., 2016). Therefore, under certain
circumstances, marine mammals whose acoustical sensors or environments
are being severely masked could also be impaired from maximizing their
performance fitness in survival and reproduction. The ability of a
noise source to mask biologically important sounds depends on the
characteristics of both the noise source and the signal of interest
(e.g., signal-to-noise ratio, temporal variability, direction), in
relation to each other and to an animal's hearing abilities (e.g.,
sensitivity, frequency range, critical ratios, frequency
discrimination, directional discrimination, age or TTS hearing loss),
and existing ambient noise and propagation conditions (Hotchkin and
Parks, 2013).
Marine mammals vocalize for different purposes and across multiple
modes, such as whistling, echolocation click production, calling, and
singing. Changes in vocalization behavior in response to anthropogenic
noise can occur for any of these modes and may result from a need to
compete with an increase in background noise or may reflect increased
vigilance or a startle response. For example, in the presence of
potentially masking signals, humpback whales and killer whales have
been observed to increase the length of their songs (Miller et al.,
2000; Fristrup et al., 2003) or vocalizations (Foote et al., 2004),
respectively, while North Atlantic right whales (Eubalaena glacialis)
have been observed to shift the frequency content of their calls upward
while reducing the rate of calling in areas of increased anthropogenic
noise (Parks et al., 2007). Fin whales (Balaenoptera physalus) have
also been documented lowering the bandwidth, peak frequency, and center
frequency of their vocalizations under increased levels of background
noise from large vessels (Castellote et al., 2012). Other alterations
to communication signals have also been observed. For example, gray
whales, in response to playback experiments exposing them to vessel
noise, have been observed increasing their vocalization rate and
producing louder signals at times of increased outboard engine noise
(Dahlheim and Castellote, 2016). Alternatively, in some cases, animals
may cease sound production during production of aversive signals
(Bowles et al., 1994, Wisniewska et al., 2018).
Under certain circumstances, marine mammals experiencing
significant masking could also be impaired from maximizing their
performance fitness in survival and reproduction. Therefore, when the
coincident (masking) sound is human-made, it may be considered
harassment when disrupting or altering critical behaviors. It is
important to distinguish TTS and PTS, which persist after the sound
exposure, from masking, which occurs during the sound exposure. Because
masking (without resulting in TS) is not associated with abnormal
physiological function, it is
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not considered a physiological effect, but rather a potential
behavioral effect (though not necessarily one that would be associated
with harassment).
The frequency range of the potentially masking sound is important
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation
sounds produced by odontocetes but are more likely to affect detection
of mysticete communication calls and other potentially important
natural sounds such as those produced by surf and some prey species.
The masking of communication signals by anthropogenic noise may be
considered as a reduction in the communication space of animals (e.g.,
Clark et al., 2009) and may result in energetic or other costs as
animals change their vocalization behavior (e.g., Miller et al., 2000;
Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2010; Holt
et al., 2009). Masking can be reduced in situations where the signal
and noise come from different directions (Richardson et al., 1995),
through amplitude modulation of the signal, or through other
compensatory behaviors, including modifications of the acoustic
properties of the signal or the signaling behavior (Hotchkin and Parks,
2013). Masking can be tested directly in captive species (e.g., Erbe,
2008), but in wild populations it must be either modeled or inferred
from evidence of masking compensation. There are few studies addressing
real-world masking sounds likely to be experienced by marine mammals in
the wild (e.g., Branstetter et al., 2013).
Masking occurs in the frequency band that the animals utilize, and
is more likely to occur in the presence of broadband, relatively
continuous noise sources such as vibratory pile driving. Energy
distribution of vibratory pile driving sound covers a broad frequency
spectrum, and is anticipated to be within the audible range of marine
mammals present in the proposed action area. Since noises generated
from the proposed construction activities are mostly concentrated at
low frequencies (<2 kHz), these activities likely have less effect on
mid-frequency echolocation sounds produced by odontocetes (toothed
whales). However, lower frequency noises are more likely to affect
detection of communication calls and other potentially important
natural sounds such as surf and prey noise. Low-frequency noise may
also affect communication signals when they occur near the frequency
band for noise and thus reduce the communication space of animals
(e.g., Clark et al., 2009) and cause increased stress levels (e.g.,
Holt et al., 2009). Unlike threshold shift, masking, which can occur
over large temporal and spatial scales, can potentially affect the
species at population, community, or even ecosystem levels, in addition
to individual levels. Masking affects both senders and receivers of the
signals, and at higher levels for longer durations, could have long-
term chronic effects on marine mammal species and populations. However,
the noise generated by KDC's proposed activities will only occur
intermittently, across an estimated 64 total days during the
authorization period in a relatively small area focused around the
proposed construction site. Thus, while KDC's proposed activities may
mask some acoustic signals that are relevant to the daily behavior of
marine mammals, the short-term duration and limited areas affected make
it very unlikely that the fitness of individual marine mammals would be
impacted.
While in some cases marine mammals have exhibited little to no
obviously detectable response to certain common or routine
industrialized activities (Cornick et al., 2011; Horsley and Larson,
2023), it is possible some animals may at times be exposed to received
levels of sound above the AUD INJ and Level B harassment thresholds
during the proposed project. This potential exposure in combination
with the nature of planned activity (e.g., vibratory pile driving,
impact pile driving, DTH) means it is possible that take by Level A and
Level B harassment could occur over the total estimated period of
activities; therefore, NMFS in response to the KDC's IHA application
proposes to authorize take by Level A and Level B harassment from the
KDC's proposed construction activities.
Airborne Acoustic Effects--Pinnipeds that occur near the project
site could be exposed to airborne sounds associated with construction
activities that have the potential to cause behavioral harassment,
depending on their distance from the specified activities. Airborne
noise would primarily be an issue for pinnipeds that are swimming or
hauled out near the project site within the range of noise levels
elevated above airborne acoustic harassment criteria. Although
pinnipeds are known to haul-out regularly on man-made objects, we
believe that incidents of take resulting solely from airborne sound are
unlikely due to the proximity between the proposed project area and the
known haul out sites for Steller sea lions (e.g., Grindall and West
Rock) and for harbor seals (e.g., to the south-southwest of the project
site), are more than 30 km (18.6 mi) away and 7.55 km (4.69 mi) away,
respectively, a significant distance outside of the predicted distances
to the in-air noise disturbance thresholds (measured at approximately
22 m (72.2 ft) and 69 m (226.4 ft), respectively) (ADOT&PF, 2023; AFSC,
2024, 2025). Cetaceans are not expected to be exposed to airborne
sounds that would result in harassment, as defined under the MMPA.
Any airborne noise would primarily be an issue for swimming or
hauled-out pinnipeds near the project site, within the range of noise
levels above the acoustic thresholds. We recognize that pinnipeds in
the water could be exposed to airborne sound that may result in
behavioral harassment when looking with their heads above water. Most
likely, airborne sound would cause behavioral responses similar to
those discussed above in relation to underwater sound. For instance,
anthropogenic sound could cause hauled-out pinnipeds to exhibit changes
in their normal behavior, such as reduction in vocalizations, or cause
them to flush from haul outs, temporarily abandon the area, and or move
further from the source. However, these animals would previously have
been `taken' because of exposure to underwater sound above the
behavioral harassment thresholds, which are in all cases larger than
those associated with airborne sound. Additionally, there are no haul
outs near the project site. Thus, the behavioral harassment of these
animals is already accounted for in these estimates of potential take.
Therefore, we do not believe that authorization of incidental take
resulting from airborne sound for pinnipeds is warranted, and airborne
sound is not discussed further here.
Potential Effects on Marine Mammal Habitat Effects
KDC's proposed construction activities could have localized,
temporary impacts on marine mammal habitat, including and their prey,
by increasing in-water SPLs and slightly decreasing water quality.
Increased noise levels may affect the acoustic habitat (see masking
discussion above) and adversely affect marine mammal prey in the
vicinity of near the project areas (see discussion below). During DTH,
impact, and vibratory pile driving or removal, elevated underwater
noise levels would ensonify the project areas where both fish and
mammals occur and could affect foraging success. Additionally, marine
mammals may avoid the area during the proposed construction activities;
however, displacement due to noise is expected to
[[Page 46846]]
be temporary and is not expected to result in long-term effects toon
the individuals or populations.
In-Water Construction Effects on Potential Foraging Habitat
As previously mentioned, the project area does not contain habitat
of known importance other than being designated as a feeding BIA for
humpback whales between May and September. While the entirety of
southeast Alaska is considered a feeding BIA for humpback whales,
Tongass Narrows represents only a tiny segment. Additionally, the
project area is highly influenced by anthropogenic activities.
The total seafloor area likely impacted by KDC's activities is
relatively small compared to the vast foraging area available habitat
in southeast Alaska. At best, the impact area provides marginal
foraging habitat for marine mammals and fish. Furthermore, pile driving
and removal at the project site would not obstruct the movement or
migration of marine mammals.
A temporary and localized increase in turbidity near the seafloor
would occur in the immediate area due to the area where piles are
installed or removed. In general, turbidity associated with pile
installation is localized to about a 25-ft (7.6-m) radius around the
pile. The sediments of the project site would settle out rapidly when
disturbed. Cetaceans are not expected to be close enough to the pile-
driving areas to experience the effects of turbidity, and any pinnipeds
could avoid localized turbid areas. Depending on the tidal stage, local
strong currents are anticipated to disburse any additional suspended
sediments produced by project activities at moderate to rapid rates.
Therefore, we expect the impact from increased noise is turbidity
levels to be discountable to marine mammals and do not discuss it
further.
The potential for prey (i.e., fish) to temporarily avoid the
immediate area is also possible. The duration of fish and marine mammal
avoidance of this area after pile driving stops is unknown, but a rapid
return to normal recruitment, distribution, and behavior is
anticipated. Any behavioral avoidance by fish or marine mammals of the
in the disturbed area would still leave significantly large areas of
fish and marine mammal foraging habitat in the nearby vicinity.
The proposed project will occur within the same footprint as
existing marine infrastructure. The nearshore and intertidal habitat
where the proposed project will occur is an area of relatively high
marine vessel traffic. Most marine mammals do not generally use the
area within the footprint of the project area. Temporary, intermittent,
and short-term habitat alteration may result from increased noise
levels during the proposed construction activities. Effects on marine
mammals will be limited to temporary displacement from pile
installation and removal noise, and effects on prey species will be
similarly limited in time and space.
Water quality--Temporary and localized reduction in water quality
will occur as a result of in-water construction activities. Most of
this effect would occur during the installation and removal of piles
when bottom sediments are disturbed. The installation and removal of
piles would disturb bottom sediments and may cause a temporary increase
in suspended sediment in the project area. During pile extraction,
sediment attached to the pile moves vertically through the water column
until gravitational forces cause it to slough off under its own weight.
The small resulting sediment plume is expected to settle out of the
water column within a few hours. Studies of the effects of turbid water
on fish (marine mammal prey) suggest that concentrations of suspended
sediment can reach thousands of milligrams per liter before an acute
toxic reaction is expected (Burton, 1993).
Impacts to water quality from DTH are expected to be similar to
those described for pile driving. Impacts to water quality would be
localized and temporary and would have negligible impacts on marine
mammal habitat. Drilling would have negligible impacts on water quality
from sediment resuspension because the system would operate within a
casing set into the bedrock. The drill would collect excavated material
inside of the apparatus where it would be lifted to the surface and
placed onto a barge for subsequent disposal.
Effects to turbidity and sedimentation are expected to be short-
term, minor, and localized. Since there may be currents that are strong
in the area, following the completion of sediment-disturbing
activities, suspended sediments in the water column should dissipate
and quickly return to background levels in all construction scenarios.
Turbidity within the water column has the potential to reduce the level
of oxygen in the water and irritate the gills of prey fish species in
the proposed project area. However, turbidity plumes associated with
the project would be temporary and localized, and fish in the proposed
project area would be able to move away from and avoid the areas where
plumes may occur. Therefore, it is expected that the impacts on prey
fish species from turbidity, and therefore on marine mammals, would be
minimal and temporary. In general, the area likely impacted by the
proposed construction activities is relatively small compared to the
available marine mammal habitat in the east Tongass Narrows.
Potential Effects on Prey. In-Water Construction Effects on Potential
Prey
Sound may affect marine mammals through impacts on the abundance,
behavior, or distribution of prey species (e.g., crustaceans,
cephalopods, fish, and zooplankton). Marine mammal prey varies by
species, season, and location and, for some, is not well documented.
Studies. Here, we describe studies regarding the effects of noise on
known marine mammal prey are described here.
Fish utilize the soundscape and components of sound in their
environment to perform important functions such as foraging, predator
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009).
Depending on their hearing anatomy and peripheral sensory structures,
which vary among species, fish hear sounds using pressure and particle
motion sensitivity capabilities and detect the motion of surrounding
water (Fay et al., 2008). The potential effects of noise on fishes
depends on the overlapping frequency range, distance from the sound
source, water depth of exposure, and species-specific hearing
sensitivity, anatomy, and physiology. Key impacts to fish may include
behavioral responses, hearing damage, barotrauma (pressure-related
injuries), and mortality.
Fish react to sounds that are especially strong and/or intermittent
low-frequency sounds and behavioral responses such as flight or
avoidance are the most likely effects. Sounds that are of short
duration and sharp can cause overt or subtle changes in fish behavior
and local distribution. The reaction of fish to noise depends on the
physiological state of the fish, past exposures, motivation (e.g.,
feeding, spawning, migration), and other environmental factors.
Hastings and Popper (2005) identified several studies that suggest fish
may relocate to avoid certain areas of sound energy. Additional studies
have documented the effects of pile driving on fish, although several
are based on studies supporting large, multiyear bridge construction
projects (e.g., Scholik and Yan, 2001, 2002; Popper and Hastings,
2009). Several studies have
[[Page 46847]]
demonstrated that impulse sounds might affect the distribution and
behavior of some fish, potentially impacting foraging opportunities or
increasing energetic costs (e.g., Fewtrell and McCauley, 2012; Pearson
et al., 1992; Skalski et al., 1992; Santulli et al., 1999; Paxton et
al., 2017). However, some studies have shown no or slight reaction to
impulse sounds (e.g., Pe[ntilde]a et al., 2013; Wardle et al., 2001;
Jorgenson and Gyselman, 2009; Cott et al., 2012). More commonly,
though, the impacts of noise on fishes are temporary.
SPLs of sufficient strength have been known to cause injury to fish
and fish mortality (summarized in Popper et al., 2014). However, in
most fish species, hair cells in the ear continuously regenerate, and
loss of auditory function is likely is restored when damaged cells are
replaced with new cells. Halvorsen et al. (2012a) showed that a TTS of
4 to 6 dB TTS was recoverable within 24 hours for one species. Impacts
would be most severe when the individual fish is close to the source
and when the duration of exposure is long. Injury caused by barotrauma
can range from slight to severe and, can cause death, and is most
likely for fish with swim bladders. Barotrauma injuries have been
documented during controlled exposure to impact pile driving (Halvorsen
et al., 2012b; Casper et al., 2013, 2017).
Fish populations in the proposed project area that serve as marine
mammal prey could be temporarily affected by noise from pile
installation and removal. The frequency range in which fishes generally
perceive underwater sounds is 50 to 2,000 Hz, with peak sensitivities
below 800 Hz (Popper and Hastings, 2009). Fish behavior or distribution
may change, especially with strong and/or intermittent sounds that
could harm fishes. High underwater SPLs have been documented to alter
behavior, cause hearing loss, and injure or kill individual fish by
causing serious internal injury (Hastings and Popper, 2005).
Zooplankton is a food source for several marine mammal species, as
well as a food source for fish that are then preyed upon by marine
mammals. Population effects on zooplankton could have indirect effects
on marine mammals. Data are limited on the effects of underwater sound
on zooplankton species, particularly sound from construction (Erbe et
al., 2019). Popper and Hastings (2009) reviewed information on the
effects of human-generated sound and concluded that no substantive data
are available on whether the sound levels from pile driving, seismic
activity, or any human-made sound would have physiological effects on
invertebrates. Any such effects would be limited to the area very near
(1 to 5 m (3.3 to 16.4 ft)) the sound source and would result in no
population effects because of the relatively small area affected at any
one time and the reproductive strategy of most zooplankton species
(short generation, high fecundity, and very high natural mortality). No
adverse impact on zooplankton populations is expected to occur from the
specified activity due in part to large reproductive capacities and
naturally high levels of predation and mortality of these populations.
Any mortalities or impacts that might occur would be negligible.
The greatest potential impact to marine mammal prey during
construction would occur during impact pile driving, vibratory pile
driving, and DTH. Impact pile driving, vibratory pile driving, and DTH
could possibly elicit behavioral reactions from fishes such as
temporary avoidance of the area but is unlikely to cause injuries to
fishes or have persistent effects on local fish populations.
Construction also would have minimal permanent and temporary impacts on
benthic invertebrate species, a marine mammal prey source. In addition,
it should be noted that the area in question is low-quality habitat
since it is already highly developed and experiences a high level of
anthropogenic noise from normal operations and other vessel traffic.
Essential Fish Habitat (EFH) has been designated in the east
Tongass Narrows for all five species of salmon (i.e., chum salmon, pink
salmon, coho salmon, sockeye salmon, and Chinook salmon (NMFS, 2017;
HDR, 2019)), which are common prey of marine mammals. Many creeks
flowing into the Sukkwan Strait and other nearby areas are known to
contain salmonids, including three primary creeks: Hydaburg River,
Natzuhini River, and Saltery Creek (Giefer and Graziano, 2022);
however, adverse effects on EFH in this area are not expected as the
proposed project location is approximately 84 km (52.2 mi) away and
heavily truncated by several landmasses.
Potential Effects on Foraging Habitat
The proposed project is not expected to result in any habitat
related effects that could cause significant or long-term negative
consequences for individual marine mammals or their populations, since
installation and removal of in-water piles would be temporary and
intermittent. The total seafloor area affected by pile installation and
removal is a very small area compared to the vast foraging area
available to marine mammals outside this project area. Although
Southeast Alaska in its entirety is listed as a BIA for humpback whales
(Wild et al., 2023), the proposed project area does not contain
particularly high-value habitat and is not unusually important for this
species or any of the other species potentially impacted by KDC's
activities. The area impacted by the project is relatively small
compared to the available habitat just outside the project area, and
there are no areas of particular importance that would be impacted by
this project. Any behavioral avoidance by fish of the disturbed area
would still leave significantly large areas of fish and marine mammal
foraging habitat in the nearby vicinity. As described in the preceding,
the potential for KDC's construction to affect the availability of prey
to marine mammals or to meaningfully impact the quality of physical or
acoustic habitat is considered to be insignificant. Therefore, impacts
of the project are not likely to have adverse effects on marine mammal
foraging habitat in the proposed project area.
In summary, given the relatively small areas being affected, as
well as the temporary and mostly transitory nature of the proposed
construction activities, any adverse effects from KDC's activities on
prey habitat or prey populations are expected to be minor and
temporary. The most likely impact to fishes at the project site would
be temporary avoidance of the area. The most likely impact on fish from
DTH and pile driving and removal activities at the project area would
be temporary behavioral avoidance of the area. The duration of fish
avoidance in this area after pile driving stops is unknown, but a rapid
return to regular recruitment, distribution, and behavior is
anticipated.
There are times of known seasonal marine mammal foraging in Tongass
Narrows around fish processing/hatchery infrastructure or when fish are
congregating, but the affected areas of Tongass Narrows are a small
portion of the total foraging habitat available in the region. In
general, effects on marine mammal prey species are expected to be minor
and temporary due to the short timeframe of the project and the small
project footprint.
Increased turbidity from construction activities can adversely
affect forage fish and juvenile salmonid out-migratory routes in the
project area. Both herring and salmon form a significant prey base for
Steller sea lions, whereas herring is the primary prey species of
humpback whales; both herring and salmon are components of the diet of
many other
[[Page 46848]]
marine mammal species that occur in the project area. Increased
turbidity is expected to happen near construction activities. However,
suspended sediments and particulates are expected to dissipate quickly
within a single tidal cycle. Given the limited area affected and high
tidal dilution rates, any effects on forage fish and salmon are
expected to be minor or negligible. In addition, best management
practices would be in effect, limiting the extent of turbidity to the
immediate project area. Finally, exposure to turbid waters from
construction activities is not expected to differ from the current
exposure; fish of the disturbed area and marine mammals in the Tongass
Narrows region are routinely exposed to substantial levels of suspended
sediment from glacial sources.
In summary, given the temporary nature of the construction project
and relatively small areas being affected, the DTH and pile driving
installation and removal activities associated with the proposed action
are not likely to have a permanent, adverse effect on any fish habitat
or populations of fish species. Any behavioral avoidance by fish in
disturbed areas would still leave significantly large areas of fish and
marine mammal foraging habitat in the nearby vicinity. Thus, we
preliminarily conclude that the impacts of the specified activities are
not likely to have more than short-term adverse effects on any prey
habitat or populations of prey species. Further, any impacts to marine
mammal habitat are not expected to result in significant or long-term
consequences for individual marine mammals, or to contribute to the
adverse effects on their populations.
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes
proposed for authorization through the IHA, which will inform NMFS'
consideration of ``small numbers,'' the negligible impact
determinations, and impacts on subsistence uses.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes would primarily be by Level B harassment, as use
of the acoustic source/s (i.e., vibratory pile driving, impact pile
driving, DTH) has the potential to result in disruption of behavioral
patterns for individual marine mammals. There is also some potential
for AUD INJ (Level A harassment) to result for low-frequency cetaceans
(i.e., mysticetes), high-frequency cetaceans (i.e., odontocetes), very-
high frequency cetaceans (i.e., odontocetes), and pinnipeds (i.e.,
phocids and otariids). The proposed mitigation and monitoring measures
are expected to minimize the severity of the taking to the extent
practicable.
As described previously, no serious injury or mortality is
anticipated or proposed to be authorized for this activity. Below we
describe how the proposed take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic criteria above which NMFS believes there is
some reasonable potential for marine mammals to be behaviorally
harassed or incur some degree of AUD INJ; (2) the area or volume of
water that will be ensonified above these levels in a day; (3) the
density or occurrence of marine mammals within these ensonified areas;
and, (4) the number of days of activities. We note that while these
factors can contribute to a basic calculation to provide an initial
prediction of potential takes, additional information that can
qualitatively inform take estimates is also sometimes available (e.g.,
previous monitoring results or average group size). Below, we describe
the factors considered here in more detail and present the proposed
take estimates.
Acoustic Criteria
NMFS recommends the use of acoustic criteria that identify the
received level of underwater sound above which exposed marine mammals
would be reasonably expected to be behaviorally harassed (equated to
Level B harassment) or to incur AUD INJ of some degree (equated to
Level A harassment). We note that the criteria for AUD INJ, as well as
the names of two hearing groups, have been recently updated (NMFS,
2024) as reflected below in the Level A harassment section.
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (hearing, motivation,
experience, demography, life stage, depth) and can be difficult to
predict (e.g., Southall et al., 2007, 2021, Ellison et al., 2012).
Based on what the available science indicates and the practical need to
use a threshold based on a metric that is both predictable and
measurable for most activities, NMFS typically uses a generalized
acoustic threshold based on received level to estimate the onset of
behavioral harassment. NMFS generally predicts that marine mammals are
likely to be behaviorally harassed in a manner considered to be Level B
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced
to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g.,
scientific sonar) sources. Generally speaking, Level B harassment take
estimates based on these behavioral harassment thresholds are expected
to include any likely takes by TTS as, in most cases, the likelihood of
TTS occurs at distances from the source less than those at which
behavioral harassment is likely. TTS of a sufficient degree can
manifest as behavioral harassment, as reduced hearing sensitivity and
the potential reduced opportunities to detect important signals
(conspecific communication, predators, prey) may result in changes in
behavior patterns that would not otherwise occur.
KDC's proposed activities includes the use of continuous (vibratory
pile driving and DTH) and impulsive (impact pile driving and DTH)
sources, and therefore the RMS SPL thresholds of 120 and 160 dB re 1
[mu]Pa are applicable.
Level A harassment--NMFS' Updated Technical Guidance for Assessing
the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version
3.0) (Updated Technical Guidance, 2024) identifies dual criteria to
assess AUD INJ (Level A harassment) to five different underwater marine
mammal groups (based on hearing sensitivity) as a result of exposure to
noise from two different types of sources (impulsive or non-impulsive).
KDC's proposed activities includes the use of impulsive (impact pile
driving and DTH) and non-impulsive (vibratory hammer and DTH) sources.
The 2024 Updated Technical Guidance criteria include both updated
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thresholds and updated weighting functions for each hearing group. The
thresholds are provided in the table below (NMFS, 2024). The
references, analysis, and methodology used in the development of the
criteria are described in NMFS' 2024 Updated Technical Guidance, which
may be accessed at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools.
Table 4--Thresholds Identifying the Onset of Auditory Injury
----------------------------------------------------------------------------------------------------------------
AUD INJ onset acoustic thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1Lpk,flat: 222 dB Cell 2LE,LF,24h:197 dB.
LE,LF,24h: 183 dB.
High-Frequency (HF) Cetaceans.......... Cell 3Lpk,flat: 230 dB.... Cell 4LE,HF,24h:201 dB.
LE,HF,24h: 193 dB.........
Very High-Frequency (VHF) Cetaceans.... Cell 5Lpk,flat: 202 Cell 6LE,VHF,24h:181 dB.
dBLE,VHF,24h: 159 dB.
Phocid Pinnipeds (PW)(Underwater)...... Cell 7Lpk,flat: 223 Cell 8LE,PW,24h:195 dB.
dBLE,PW,24h: 183 dB.
Otariid Pinnipeds (OW)(Underwater)..... Cell 9Lpk,flat: 230 Cell 10LE,OW,24h:199 dB
dBLE,OW,24h: 185 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric criteria for impulsive sounds: Use whichever criteria results in the larger isopleth for
calculating AUD INJ onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure
level criteria associated with impulsive sounds, the PK SPL criteria are recommended for consideration for non-
impulsive sources.
Note: Peak sound pressure level (Lp,0-pk) has a reference value of 1 [micro]Pa, and weighted cumulative sound
exposure level (LE,p) has a reference value of 1 [micro]Pa\2\s. In this table, criteria are abbreviated to be
more reflective of International Organization for Standardization standards (ISO, 2017). The subscript
``flat'' is being included to indicate peak sound pressure are flat weighted or unweighted within the
generalized hearing range of marine mammals underwater (i.e., 7 Hz to 165 kHz). The subscript associated with
cumulative sound exposure level criteria indicates the designated marine mammal auditory weighting function
(LF, HF, and VHF cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is 24 hours.
The weighted cumulative sound exposure level criteria could be exceeded in a multitude of ways (i.e., varying
exposure levels and durations, duty cycle). When possible, it is valuable for action proponents to indicate
the conditions under which these criteria will be exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area ensonified above the
acoustic thresholds, including source levels and transmission loss
coefficient.
The sound field in the project area is the existing background
noise plus additional construction noise from the proposed project.
Marine mammals are expected to be affected via sound generated by the
primary components of the project (i.e., impact pile driving, vibratory
pile driving, and DTH). The source levels assumed for both removal and
installation activities is based on reviews of measurements of the same
or similar types and dimensions of piles available in the scientific
literature and from similar coastal construction projects. The source
level for the piles and activities (i.e., installation or removal) are
presented in table 5.
Table 5--Ketchikan Berth IV Expansion Project Sound Proxy Sources
------------------------------------------------------------------------
Sound source level Sound proxy
Pile type at 10 m (32.8 ft) source(s)
------------------------------------------------------------------------
Vibratory Hammer
------------------------------------------------------------------------
24-in steel piles............... 163 dB............ NMFS (2023).
30-in steel piles............... 166 dB............ NMFS (2023).
36-in steel piles............... 166 dB............ NMFS (2023).
48-in steel piles............... 171 dB............ NMFS (2023).
------------------------------------------------------------------------
Impact hammer
------------------------------------------------------------------------
36-in steel piles............... dB rms: 193 dB; dB Caltrans (2015),
SEL: 183 dB; dB and Caltrans
peak: 210 dB:. (2020).
48-in steel piles............... dB rms: 192 dB; dB Caltrans (2020).
SEL: 179 dB; dB
peak: 213 dB:.
------------------------------------------------------------------------
DTH
------------------------------------------------------------------------
36-in steel piles............... dB rms: 174 dB; dB NMFS (2022a).
SEL: 164 dB; dB Denes et al.
peak: 194 dB:. (2019); Reyff &
Heyvaert (2019);
Reyff (2020).
48-in steel piles *............. dB rms: 178 dB dB NMFS internal
SEL: 168 dB dB guidance.
peak: n/a.
------------------------------------------------------------------------
* A bubble curtain would be employed, reducing the SEL value by
approximately 5 dB.
Level B Harassment
Transmission Loss (TL) is the decrease in acoustic intensity as an
acoustic pressure wave propagates out from a source. TL parameters vary
with frequency, temperature, sea conditions, current, source and
receiver depth, water depth, water chemistry, and bottom composition
and topography. The general formula for underwater TL is:
TL = B x Log10(R1/R2),
where:
TL = transmission loss in dB,
B = transmission loss coefficient,
R1 = the distance of the modeled SPL from the driven pile, and
R2 = the distance from the driven pile of the initial measurement.
This formula neglects loss due to scattering and absorption, which
is assumed to be zero here. The degree to
[[Page 46850]]
which underwater sound propagates away from a sound source depends on
various factors, most notably the water bathymetry and the presence or
absence of reflective or absorptive conditions, including in-water
structures and sediments. Spherical spreading occurs in a perfectly
unobstructed (free-field) environment not limited by depth or water
surface, resulting in a 6 dB reduction in sound level for each doubling
of distance from the source (20*log[range]). Cylindrical spreading
occurs in an environment in which sound propagation is bounded by the
water surface and sea bottom, resulting in a reduction of 3 dB in sound
level for each doubling of distance from the source (10*log[range]). A
practical spreading value of 15 is often used under conditions where
water increases with depth as the receiver moves away from the
shoreline, resulting in an expected propagation environment that would
lie between spherical and cylindrical spreading loss conditions. Absent
site-specific acoustical monitoring with differing measured TL,
practical spreading is used. Site-specific TL data for Ketchikan is not
available; therefore, the default coefficient of 15 is used to
determine the distances to the Level A harassment and Level B
harassment thresholds.
Level A Harassment
The ensonified area associated with Level A harassment is more
technically challenging to predict due to the need to account for a
duration component. Therefore, NMFS developed an optional User
Spreadsheet tool to accompany the 2024 Updated Technical Guidance that
can be used to relatively simply predict an isopleth distance for use
in conjunction with marine mammal density or occurrence to help predict
potential takes (found on our website here: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools). We note that because
of some of the assumptions included in the methods underlying this
optional tool, we anticipate that the resulting isopleth estimates are
typically going to be overestimates of some degree, which may result in
an overestimate of potential take by Level A harassment. However, this
optional tool offers the best way to estimate isopleth distances when
more sophisticated modeling methods are not available or practical. For
stationary sources, such as vibratory pile driving, impact pile
driving, and DTH, the optional User Spreadsheet tool predicts the
distance at which, if a marine mammal remained at that distance for the
duration of the activity, it would be expected to incur AUD INJ. Inputs
used in the optional User Spreadsheet tool, and the resulting estimated
isopleths, are reported below in tables 6, 7, and 8.
Table 6--User Spreadsheet Inputs for Vibratory Pile Driving (MMPA ITA Application--Appendix B)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Tab of spreadsheet User spreadsheet variables
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-inch 48-inch
30-inch 30-inch 36-inch steel permanent steel permanent steel
Pile information 24-inch steel 30-inch steel temporary steel temporary steel pile removal pile pile
pile removal \a\ pile removal \a\ pile pile removal \a\ \a\ installation installation
installation \a\ \a\ \a\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sound Pressure Level (dB).... 163 166 166 166 166 166 171
(unattenuated (unattenuated (unattenuated (unattenuated (unattenuated (unattenuated (unattenuated
and attenuated). and attenuated). and attenuated). and attenuated). and and and
attenuated). attenuated). attenuated).
Distance associated with 10.............. 10.............. 10.............. 10.............. 10............. 10............. 10.
sound pressure level
(meters).
Transmission loss constant... 15.............. 15.............. 15.............. 15.............. 15............. 15............. 15.
Number of piles per day...... 2............... 4............... 4............... 4............... 4.............. 1.............. 2.
Duration to drive pile 15.............. 15.............. 30.............. 10.............. 15............. 60............. 60.
(minutes).
Duration of sound production 1,800........... 3,600........... 7,200........... 2,400........... 3,600.......... 3,600.......... 7,200.
in a day (seconds).
Marine Mammal default WFA 2.5............. 2.5............. 2.5............. 2.5............. 2.5............ 2.5............ 2.5.
(kHz).
Cumulative SEL at measured 195.55.......... 201.56.......... 204.57.......... 199.80.......... 201.56......... 201.56......... 209.57.
distance (dB).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Proxy source PR1 2023 Calculations Proxy Recommendations for Southeast Alaska (July 19, 2023).
Table 7--User Spreadsheet Inputs for Impact Pile Driving (MMPA ITA
Application--Appendix B)
------------------------------------------------------------------------
Tab of spreadsheet User spreadsheet variables
------------------------------------------------------------------------
36-inch impact 48-inch impact
Pile information installation \a\ installation \b\
------------------------------------------------------------------------
Peak (dB)....................... 210 (unattenuated 213 (unattenuated
and attenuated). and attenuated).
SELss (dB)...................... 183 (unattenuated 179 (unattenuated
and attenuated). and attenuated).
RMS (dB)........................ 193 (unattenuated 193 (unattenuated
and attenuated). and attenuated).
Distance associated with sound 10................ 10.
pressure level (meters).
Transmission loss constant...... 15................ 15.
Number of piles per day......... 2................. 3.
Number of strikes per pile...... 200............... 200.
Number of strikes per day 400............... 600.
(seconds).
Attenuation assumed............. 0................. 0.
Cumulative SEL at measured 209............... 207.
distance.
------------------------------------------------------------------------
\a\ 36-inch impact install Source: NMFS 2023 Proxy Recommendations for
Southeast Alaska.
\b\ Proxy Email correspondence between Tony Lewkowski, Solstice Alaska
Consulting, Inc., and Cara Hotchkin, NMFS, on April 14, 2025.
[[Page 46851]]
Table 8--User Spreadsheet Inputs for Down-the-Hole (DTH) Stationary
Source (Impulsive, Intermittent) (MMPA ITA Application--Appendix B)
------------------------------------------------------------------------
Tab of spreadsheet User spreadsheet variables
------------------------------------------------------------------------
48-inch steel pile
DTH source
Pile information 36-inch DTH source installation (with
\a\ bubble curtain)
\b\
------------------------------------------------------------------------
Level A Harassment (SELCUM)
------------------------------------------------------------------------
Weighting Factor Adjustment 2................. 2.
(kHz).
Unweighted SELCUM............... 220.4............. 217.6.
Single Strike SELss............. 164............... 163.
Strike rate (average strikes per 10................ 10.
second).
Duration to drive pile/drill 360............... 480.
hole (minutes).
Number of piles/holes per day... 2................. 1.
Transmission loss coefficient... 15................ 15.
Distance of single strike SELss. 10................ 10.
Total number of strikes in a 24- 432,000........... 288,000.
hour period.
------------------------------------------------------------------------
Level A Harassment (Peak (PK))
------------------------------------------------------------------------
L p,0-pk specified at ``x'' 194............... 178.
meters.
Distance of L p,0-pk measurement 10................ 10.
(meters).
L p,0-pk Source level........... 209.0............. 193.0
------------------------------------------------------------------------
Level B Harassment (SPL)
------------------------------------------------------------------------
SPL (RMS)....................... 174............... 178.
Distance........................ 10................ 10.
Transmission loss coefficient... 15LogR (practical 15LogR (practical
spreading). spreading).
------------------------------------------------------------------------
\a\ Proxy National Marine Fisheries Services: Acoustic Guidance for
Assessment of Down-the-Hole (DTH) Systems November 2022.
\b\ Proxy Email correspondence between Tony Lewkowski, Solstice Alaska
Consulting, Inc., and Cara Hotchkin, NMFS, on April 14, 2025.
Using the practical spreading model, NMFS determined that the
underwater noise would yield the following calculated distances to the
Level A harassment and Level B harassment thresholds for marine mammals
(see table 9).
Table 9--Ketchikan Berth IV Expansion Project Calculated Distances to the Level A Harassment and Level B Harassment Acoustic Thresholds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Calculated distance (m) and (area (km\2\)) of Level A Harassment and Level B Harassment
thresholds
-----------------------------------------------------------------------------------------------
Activity Method Level B Harassment
Level A -------------------------------------------------------------------------------
Harassment LFC HFC VHFC PW OW
--------------------------------------------------------------------------------------------------------------------------------------------------------
Barge movements, pile positioning, -................... 10 10 10 10 10 10
etc.. (0.007) (0.007) (0.007) (0.007) (0.007) (0.007)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory pile driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-in steel pile.................. Removal............. 7.9 3.0 6.5 10.2 3.4 7,356.4
(0.006) (0.002) (0.004) (0.007) (0.002) (7.321)
30-in steel pile.................. Removal............. 19.9 7.6 16.2 25.6 8.6 11,659.1
(0.014) (0.005) (0.012) (0.019) (0.006) (11.577)
36-in steel pile.................. Removal............. 19.9 7.6 16.2 25.6 8.6 11,659.1
(0.014) (0.005) (0.012) (0.019) (0.006) (11.577)
30-in steel temporary pile........ Installation........ 31.5 12.1 25.8 40.6 13.7 11,659.1
(0.023) (0.009) (0.019) (0.030) (0.010) (11.577)
30-in steel temporary pile........ Removal............. 15.2 5.8 12.4 19.5 6.6 11,659.1
(0.011) (0.004) (0.009) (0.014) (0.005) (11.577)
36-in steel permanent pile........ Installation........ 19.9 7.6 16.2 25.6 8.6 11,659.1
(0.014) (0.005) (0.012) (0.019) (0.006) (11.577)
48-in steel permanent............. Installation........ 68.0 26.1 55.5 87.5 29.4 25,118.9
(0.053) (0.019) (0.043) (0.069) (0.022) (22.769)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact pile driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-in steel permanent pile........ Installation........ 540.2 68.9 835.9 479.9 178.9 1,584.9
(0.740) (0.054) (1.46) (0.619) (0.159) (3.557)
48-in steel permanent pile........ Installation........ 383.1 48.9 592.8 340.3 126.8 1,359.4
(0.446) (0.037) (0.855) (0.376) (0.104) (2.864)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Down the Hole (DTH) Drilling
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-in steel permanent............. Installation........ 3,077.1 392.6 4,761.9 2,733.6 1,019.0 39,811
(5.086) (0.462) (5.788) (4.931) (1.929) (39.918)
[[Page 46852]]
48-in steel permanent pile*....... Installation........ 2,014.1 257.0 3,116.9 1,789.3 667.0 34,145.0
(4.351) (0.2555) (5.102) (4.054) (1.028) (32.164)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: LFC = low-frequency cetaceans; HFC = high-frequency cetaceans; VHFC = very high-frequency cetaceans; PW = phocid pinnipeds (in-water); OW =
otariids pinnipeds (in-water).
* Includes a bubble curtain.
It should be noted that, based on the geography of Tongass Narrows
and the surrounding islands, the sound would not reach the entire
distance of the Level B harassment isopleths. Landmasses would truncate
the largest Level B Harassment isopleths. Constraining landmasses
include Revillagigedo Island, Gravina Island, Pennock Island, Annette
Island, and Bold Island.
Marine Mammal Occurrence and Take Estimation
In this section, we provide information about the occurrence of
marine mammals, including density or other relevant information, which
will inform the take calculations. Next, we describe how all of the
information described above is synthesized to produce a quantitative
estimate of the take that is reasonably likely to occur and proposed
for authorization.
In their application, KDC explained that the animal occurrence data
was collated based upon protected species monitoring data collected
during the Alaska Department of Transportation & Public Facilities'
(ADOT&PF) Ferry Berth Improvements projects located in Tongass Narrows,
conducted between 2020-2023. These projects and the available
monitoring reports can be found on NMFS' website (https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities). Additionally, KDC
consulted with local sources (i.e., Allen Marine Tours, a tour boat
operator based in Ketchikan; Sampson Tug and Barge, a tug and barge
crew based in Ketchikan; and Barbara Morgan, a faculty member at the
University of Alaska Southeast, Ketchikan) for anecdotal information to
support the sighting data. All species that could potentially occur in
the project area were classified as ``common,'' ``frequent,''
``infrequent,'' ``rare,'' or ``very rare'' (see table 6 in the ITA
application). For the three species/stocks who were determined to have
``rare'' or ``very rare'' occurrence in the project area (i.e., gray
whales, fin whales (Balaenoptera physalus), and Pacific white-sided
dolphins (Lagenorhynchus obliquidens), no take was requested and these
were not carried forward. The only exception to this is the Mexico-
North Pacific stock of humpback whales. While that stock is considered
``Rare'' since they only make up two percent of the humpback whales in
southeast Alaska, Protected Species Observers (PSOs) likely will not be
able to differentiate between that stock and the ``Common'' Hawaii DPS.
Therefore, both stocks have been requested. These assumptions and
information for the calculations are shown below in table 10.
Table 10--Occurrence Information and Assumptions That Were Considered When Determining the Proposed Take
----------------------------------------------------------------------------------------------------------------
Species occurrence information and
Marine mammal species assumptions for take calculations Occurrence ctatus
----------------------------------------------------------------------------------------------------------------
Minke whale............................. Infrequent throughout Southeast Alaska Infrequent.
inland waters, could occur each month.
Seasonality not determined but have been
observed in spring, summer, and fall.
Usually sighted alone rather than in
groups, estimate 1 whale per group.
Conservatively assume one group per month.
Level A harassment take estimates one
group per month during the 34 days of DTH
and anchoring when the Level A isopleth
exceeds 1,000 m (3,280 ft).
Humpback whale.......................... Common visitors to Tongass Narrows, could Rare
occur each day. (Mexico-North Pacific DPS)
More frequent in the summer months, but \a\
year-round presence is increasing in Common
Southeast Alaska. (Hawaii DPS).
Usually sighted in groups of one to four;
estimate 2 whales per group.
Level A harassment take estimates one
whale per day during the 34 days of DTH
and anchoring.
Level B harassment take estimated one
group per day during the 64 days of the
project.
Killer whale............................ Often observed in Southeast Alaska inland Frequent.
waterways.
Frequent visitors to Tongass Narrows,
could occur each month.
More frequently seen in summer and fall
but may be present year-round.
Groups of 2-7 spotted during ADOT&PF
project in Tongass Narrows (ADOT&PF,
2023); estimate 7 whales per group.
1-2 groups spotted per month; 2 groups per
month used for estimates.
Level B harassment take estimates four
groups per month during the 64 days of
the project.
Dall's porpoise......................... Infrequently observed within Tongass Infrequent.
Narrows, could occur each month.
Groups range from 3 to 6 animals; estimate
6 porpoises per group.
Level A harassment take estimates 1 group
per month during the 41 days of impact
driving, DTH, and anchoring when Level A
isopleth exceeded 200 m (656 ft).
Level B harassment take estimates 1 group
per month during the 64 days of the
project.
Harbor porpoise......................... Frequently observed near the project area, Frequent.
could occur month.
Groups range from 3 to 5 animals; estimate
5 porpoises per group.
Level A harassment take estimates 4 group
per month during the 41 days of impact
pile driving, DTH, and anchoring when
Level A isopleth exceeds 200 m (656 ft).
Level B harassment take estimates 4 group
per month during the 64 days of the
project.
[[Page 46853]]
Harbor seal............................. Common in Tongass Narrows, could occur Common.
each day.
Group sizes of 1-3 most common in Tongass
Narrows (ADOT&PF, 2023); estimate 3
harbor seals per group.
Per consultation with local tour
operators, species common in Tongass
Narrows; conservative estimates of 2
groups per day used in take estimates.
Level A harassment take estimates 2 groups
per day during the 41 day of impact pile
driving, DTH, and anchoring when Level A
isopleth exceeds 200 m (656 ft).
Level B harassment take estimates 2 groups
per day during 64 days of the project.
Northern elephant seal.................. Infrequent in Tongass Narrows, Infrequent.
Revillagigedo Channel and Nichols
Passage, but sightings increasing, could
occur each month.
Estimate 1 northern elephant seal per
group.
Level A harassment take estimates 1 group
per month during the 41 day of impact
pile driving, DTH, and anchoring when the
Level A isopleth exceeds 200 m (656 ft).
Level B harassment take estimates 1 group
per month during 64 days of the project.
Steller sea lion........................ Steller sea lions are commonly seen in the Common.
project area, could occur each day.
Highly social animals, gathering in large
groups on and near rookeries and major
haul outs.
Closest documented haul out is Grindall,
32.19 km (20 mi) away from the project
area.
Group sizes of 1-2 most common in Tongass
Narrows (ADOT&PF, 2023); estimate 2
Steller sea lions per group.
Level A harassment take estimates 1 group
per day during the 34 days of DTH and
anchoring when the Level A isopleth
exceeds 200 m (656 ft).
Level B harassment take estimates 1 group
per day during the 64 days of the project.
----------------------------------------------------------------------------------------------------------------
\a\--The Mexico-North Pacific DPS is considered ``Rare'' since they only make up two percent of the humpback
whales in southeast Alaska; however, PSOs likely will not be able to differentiate between that stock and the
``Common'' Hawaii DPS. Therefore, both stocks have been requested.
To calculate the estimated take that is expected to occur from
KDC's proposed activities, species-specific expected occurrence, which
is based on group size data and the estimated frequency of appearance
expected for each species (table 11), was multiplied by the total
number of days that each type of pile driving (i.e., impact, vibratory,
DTH) would be needed. These were calculated either daily or monthly,
depending on the occurrence information available for each species:
Estimated take (daily) = Group size x Groups per day x Days of pile
driving; and
Estimated take (monthly) = Group size x Groups per month (i.e., 30-day
period) x Months of pile driving activity (i.e., Number of days of pile
driving activity/30 days))
The equation for daily estimated take was used for species whose
occurrence was ``common'' and therefore had a daily occurrence
estimate. The equation for monthly estimated take was used for all
other species.
While KDC primarily expects take by Level B harassment to occur, a
small amount of take by Level A harassment is expected for all low-
frequency cetaceans, very high-frequency cetaceans, phocids, and
otariids. Table 11 shows if the estimated takes for each species were
calculated on a monthly or daily basis, based on the observation and
sighting data available. The proposed takes are shown in table 12.
Table 11--Daily or Monthly Occurrence of Each Marine Mammal Species
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment Level B harassment
----------------------------------------------------------------------------
Number of Number of Number of
Species Occurrence metric Number of animals Number of pile Number of Number of pile
animals per day groups driving animals groups driving
per group \a\ per month days \b\ per group per month days \b\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale............................. Daily......................... - 1 - 34 2 1 64
Minke whale................................ Monthly....................... 1 - 1 34 1 1 64
Killer whale............................... Monthly....................... - - - - 7 4 64
Dall's porpoise............................ Monthly....................... 6 - 1 41 6 1 64
Harbor porpoise............................ Monthly....................... 5 - 4 41 5 4 64
Steller sea lion........................... Daily......................... 2 - 1 34 2 1 64
Harbor seal................................ Daily......................... 3 - 2 41 3 2 64
Northern elephant seal..................... Monthly....................... 1 - 1 41 1 1 64
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ For the calculation for take by Level A harassment of humpback whales, the number of whales per days rather than individuals per group was chosen as
the more appropriate metric.
\b\ Only for species where data was derived ``monthly'', the number of pile driving days was divided by 30 days.
Table 12--Take Calculation and Summary of the Proposed Take for the Ketchikan Berth IV Expansion Project
--------------------------------------------------------------------------------------------------------------------------------------------------------
Take proposed for authorization Percentage of
------------------------------------------- total stock
Common name Stock \a\ NMFS stock abundance proposed for
Level A Level B Total authorization
harassment harassment \b\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale......................... Hawai[revaps]i DPS........ 11,278................... 34 128 162 1.44
Mexico-North Pacific DPS.. 918...................... 17.65
Minke whale............................ Alaska.................... N/A...................... 2 3 5 N/A
[[Page 46854]]
Killer whale........................... West Coast Transient...... 349...................... 0 60 60 17.19
Eastern North Pacific 302...................... 19.87
Northern Resident 1,920.................... 3.13
(British Columbia).
Eastern North Pacific
Alaska Resident.
Dall's porpoise........................ Alaska.................... 13,110................... 9 12 21 0.16
Harbor porpoise........................ Southern Southeast Alaska-- 890...................... 28 43 71 7.98
Inland waters.
Steller sea lion....................... Eastern................... \c\ 36,308............... 68 128 196 0.54
Harbor seal............................ Clarence Strait........... 27,659................... 246 384 630 2.28
Northern elephant seal................. California breeding....... 187,386.................. 2 3 5 <0.01
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Stock estimates from the most recent NMFS stock assessment reports, unless otherwise noted.
\b\ Percent of stock refers to combined take by both Level B harassment and Level A harassment (where requested). If there is more than one stock of a
species, the percent of stock is calculated as if all takes went to a single stock.
\c\ Steller sea lion takes represent multiple takes of the same individuals that frequent the project area; however, for purposes of percent of stock
calculation, take totals assume separate individuals of the species.
Proposed Mitigation
In order to issue an IHA under section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to the
activity, and other means of effecting the least practicable impact on
the species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of the species or stock for taking for certain
subsistence uses (latter not applicable for this action). NMFS
regulations require applicants for incidental take authorizations to
include information about the availability and feasibility (economic
and technological) of equipment, methods, and manner of conducting the
activity or other means of effecting the least practicable adverse
impact upon the affected species or stocks, and their habitat (50 CFR
216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, NMFS
considers two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat, as
well as subsistence uses. This considers the nature of the potential
adverse impact being mitigated (likelihood, scope, range). It further
considers the likelihood that the measure will be effective if
implemented (probability of accomplishing the mitigating result if
implemented as planned), the likelihood of effective implementation
(probability implemented as planned), and;
(2) The practicability of the measures for applicant
implementation, which may consider such things as cost, and impact on
operations.
The mitigation requirements described in the following were
proposed by KDC in its adequate and complete application or are the
result of subsequent coordination between NMFS and KDC. KDC has agreed
that all of the mitigation measures are practicable. NMFS has fully
reviewed the specified activities and the mitigation measures to
determine if the mitigation measures would result in the least
practicable adverse impact on marine mammals and their habitat, as
required by the MMPA, and has determined the proposed measures are
appropriate. NMFS describes these below as proposed mitigation
requirements, and has included them in the proposed IHA.
In addition to the measures described later in this section, KDC
would follow these general mitigation measures:
Takes proposed for authorization, by Level A and Level B
harassment only, would be limited to the species and numbers listed in
table 12. Construction activities would be required to be halted upon
observation of either a species for which incidental take was not
authorized or for a species for which incidental take has been
authorized but the number of takes has been met, entering or is within
the harassment zone, if the IHA is issued.
The taking by serious injury or death of any of the
species listed in table 12 or any taking of any other species of marine
mammal would be prohibited and would result in the modification,
suspension, or revocation of the IHA, if issued. Any taking exceeding
the authorized amounts listed in table 12 would be prohibited and would
result in the modification, suspension, or revocation of the IHA, if
issued;
Ensure that construction supervisors and crews, the marine
mammal monitoring team, and relevant KDC staff are trained prior to the
start of all construction activities, so that responsibilities,
communication procedures, marine mammal monitoring protocol, and
operational procedures are clearly understood. New personnel joining
during the project must be trained prior to commencing work;
KDC, construction supervisors and crews, PSOs, and
relevant KDC staff must avoid direct physical interaction with marine
mammals during construction activity. If a marine mammal comes within
10 m (32.8 ft) of such activity, operations must cease and vessels must
reduce speed to the minimum level required to maintain steerage and
safe working conditions, as necessary to avoid direct physical
interaction;
Employ PSOs and establish monitoring locations as
described in the Protected Species Monitoring and Mitigation Plan
(PSMMP) (see NMFS' website). KDC must monitor the project area to the
maximum extent possible based on the required number of PSOs, required
monitoring locations, and environmental conditions;
KDC also would abide by the reasonable and prudent
measures and terms and conditions of a Biological Opinion and
Incidental Take Statement, if issued by NMFS, pursuant to Section 7 of
the ESA.
Additionally, the following mitigation measures apply to KDC's in-
water construction activities.
[[Page 46855]]
Pre- and Post-Activity Monitoring
KDC would be required to establish pre- and post-monitoring zones
with radial distances (based on the distances to the Level B harassment
threshold), as identified in table 13, for all construction activities.
Table 13--Proposed Monitoring Zones During Project Activities
------------------------------------------------------------------------
Distance (m) to the Level B
harassment thresholds \a\
Activity -------------------------------
All hearing groups
------------------------------------------------------------------------
Barge movements, pile positioning, etc.. 10
------------------------------------------------------------------------
Vibratory pile driving/removal
------------------------------------------------------------------------
24-inch steel pile removal.............. 7,360
30-inch steel pile removal.............. 11,660
36-inch steel pile removal.............. 11,660
30-inch temporary pile installation..... 11,660
30-inch temporary pile removal.......... 11,660
36-inch permanent pile installation..... 11,660
48-inch permanent pile installation..... 25,120
In-air (all piles)...................... PW: 50 \b\
OW: 15 \b\
------------------------------------------------------------------------
Impact pile driving
------------------------------------------------------------------------
36-inch permanent pile installation..... 1,585
48-inch permanent pile installation..... 1,360
In-air (all piles)...................... PW: 65 \b\
OW: 20 \b\
------------------------------------------------------------------------
Down-the-Hole (DTH) Drilling
------------------------------------------------------------------------
36-inch permanent pile installation..... 39,815 \c\
48-inch permanent pile installation..... 34,145
------------------------------------------------------------------------
Note: PW = phocid pinnipeds (in-water); OW = otariids pinnipeds (in-
water).
\a\--Distances, in meters, refer to the maximum radius of the zone and
are rounded.
\b\--As described in the Effects section, NMFS does not expect cetaceans
to be affected by in-air noise. These distances are precautionary.
\c\--Monitoring zone DTH drilling the 36-inch piles is larger than the
monitoring zone for the 48-inch piles due to use of a bubble curtain
for the 48-inch piles.
Monitoring would take place from 30 minutes prior to initiation of
any pile driving activity (i.e., pre-start clearance monitoring)
through 30 minutes post-completion of pile driving activity. In
addition, monitoring for 30 minutes would take place whenever a break
in the specified activity (i.e., impact pile driving, vibratory pile
driving, DTH) of 30 minutes or longer occurs. Pre-start clearance
monitoring would be conducted during periods of visibility sufficient
for the lead PSO to determine that the shutdown zones (indicated
further below) are clear of marine mammals. Pile driving may commence
following 30 minutes of observation when the determination is made that
the shutdown zones are clear of marine mammals.
Soft-start
KDC would use soft start techniques when impact pile driving. Soft-
start requires contractors to provide an initial set of three strikes
at reduced energy, followed by a 30-second waiting period, then two
subsequent reduced-energy strike sets. A soft-start would be
implemented at the start of each day's impact pile driving and at any
time following cessation of impact pile driving for a period of 30
minutes or longer. Soft-start procedures are used to provide additional
protection to marine mammals by providing warning and/or giving marine
mammals a chance to leave the area prior to the hammer operating at
full capacity.
Establishment of Shutdown Zones
KDC would establish shutdown zones with radial distances as
identified in table 14 for all construction activities. The purpose of
a shutdown zone is generally to define an area within which shutdown of
the activity would occur upon sighting of a marine mammal (or in
anticipation of an animal entering the defined area). Shutdown zones
would vary based on the activity type and marine mammal hearing group.
If a marine mammal is observed entering or within the shutdown zones
indicated in table 14, pile driving and DTH activities must be delayed
or halted. If pile driving is delayed or halted due to the presence of
a marine mammal, the activity may not commence or resume until either
the animal has voluntarily exited and been visually confirmed beyond
the shutdown zones or a specific time period has passed without re-
detection of the animal (i.e., 30 minutes for cetaceans, 15 minutes for
pinnipeds). If a marine mammal comes within or approaches the shutdown
zone indicated in table 14, such operations must cease.
[[Page 46856]]
Table 14--Proposed Shutdown Zones During Project Activities
----------------------------------------------------------------------------------------------------------------
Distance (m) to level A harassment thresholds
Activity -------------------------------------------------------------------------------
LFC HFC VHFC PW OW
----------------------------------------------------------------------------------------------------------------
Barge movements, pile 10 10 10 10 10
positioning, etc...............
----------------------------------------------------------------------------------------------------------------
Vibratory pile driving/removal
----------------------------------------------------------------------------------------------------------------
24-inch steel pile removal...... 10 10 10 15 10
30-inch steel pile removal...... 20 10 20 30 10
36-inch steel pile removal...... 20 10 20 30 10
30-inch temporary pile 35 15 30 45 15
installation...................
30-inch temporary pile removal.. 20 10 15 20 10
36-inch permanent pile 20 10 20 30 10
installation...................
48-inch permanent pile 70 30 60 90 30
installation...................
In-air (all piles).............. - - - - -
----------------------------------------------------------------------------------------------------------------
Impact pile driving
----------------------------------------------------------------------------------------------------------------
36-inch permanent pile 545 70 200 200 180
installation...................
48-inch permanent pile 385 50 200 200 130
installation...................
In-air (all piles).............. - - - - -
----------------------------------------------------------------------------------------------------------------
Down-the-Hole (DTH) Drilling
----------------------------------------------------------------------------------------------------------------
36-inch permanent pile 1,000 395 200 200 200
installation...................
48-inch permanent pile 1,000 260 200 200 200
installation...................
----------------------------------------------------------------------------------------------------------------
Note: LFC = low-frequency cetaceans; HFC = high-frequency cetaceans; VHFC = very high-frequency cetaceans; PW =
phocid pinnipeds (in-water); OW = otariids pinnipeds (in-water).
Bubble Curtain
KDC would use a bubble curtain during impact pile driving. The
bubble curtain would be operated as necessary to achieve optimal
performance. At a minimum, the bubble curtain would distribute air
bubbles around 100 percent of the piling circumference for the full
depth of the water column, the lowest bubble ring would be in contact
with the substrate for the full circumference of the ring, and the
weights attached to the bottom ring would ensure 100 percent substrate
contact. No parts of the ring or other objects would prevent full
substrate contact. In addition, airflow to the bubblers would be
balanced around the circumference of the pile.
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined that the proposed mitigation measures
provide the means of effecting the least practicable impact on the
affected species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, and areas of similar
significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104(a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present while
conducting the activities. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the activity; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and
Mitigation and monitoring effectiveness.
The monitoring and reporting requirements described in the
following were proposed by KDC in its adequate and complete application
and PSMMP, or are the result of subsequent coordination between NMFS
and KDC following receipt of the application. KDC has agreed that all
of the mitigation measures are appropriate. NMFS describes these below
as proposed requirements, and has included them in the proposed IHA.
Proposed Monitoring
Visual Monitoring
All PSOs must be NMFS-approved. PSOs would be independent of the
activity contractor (for example, employed by a subcontractor) and have
no other assigned tasks during monitoring periods. At least one PSO
would have prior experience performing the duties of a PSO during an
activity pursuant to a NMFS-issued Incidental Take Authorization (ITA).
Other PSOs may substitute other relevant experience (including relevant
Alaska Native traditional knowledge), education (degree in biological
science or related field), or training for prior experience performing
the duties of a PSO during construction activity pursuant to a NMFS-
issued incidental take authorization.
[[Page 46857]]
Additionally, PSOs would be required to meet the following
qualifications:
The ability to conduct field observations and collect data
according to assigned protocols;
Experience or training in the field identification of
marine mammals, including the identification of behaviors;
Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
Writing skills sufficient to prepare a report of
observations including but not limited to:
(1) Number and species of marine mammals observed;
(2) Dates and times when in-water construction activities were
conducted;
(3) Dates, times, and reason for implementation of mitigation (or
why mitigation was not implemented when required); and
(4) Marine mammal behavior.
The ability to communicate orally, by radio or in person,
with Project personnel to provide real-time information on marine
mammals observed in the area as necessary.
Where a team of three or more PSOs is required, a lead observer or
monitoring coordinator would be designated. The lead observer must have
prior experience performing the duties of a PSO during construction
activity pursuant to a NMFS-issued ITA or Letter of Concurrence.
KDC must establish monitoring locations as described in PSMMP (see
NMFS' website). For all pile driving activities, a minimum of one PSO
must be assigned to each active pile driving and DTH location to
monitor the applicable shutdown zones. The specific locations of the
PSOs will be based on project activities and are as follows (in
alignment with the PSMMP (see figure 2)):
Station 1: Boardwalk adjacent to the Oyster Shack and
Berth IV;
Station 2: Ketchikan Berth I;
Station 3: Rotary Beach Park Buggy Beach;
Station 4: Mountain Point, shoreline near the boat launch.
As described in the PSMMP, the number and locations of monitors
will be based on the following in-water work scenarios:
Scenario #1: In-water construction not involving pile
driving (e.g., barge movements, etc.)--one location (Station 1);
Scenario #2: Vibratory pile driving for removal/
installation of all pile sizes and impact pile driving for installation
of all pile sizes--two locations (Station 1 and Station 2);
Scenario #3: DTH drilling--three locations (Station 1,
Station 3, and Station 4).
At all locations, all PSOs, to the extent practicable, must use an
elevator platform at observation points to enhance observation ability.
PSOs would be required to record all observations of marine mammals,
regardless of distance from the pile being driven, as well as the
additional data indicated below and in section 6 of the IHA, if issued.
[GRAPHIC] [TIFF OMITTED] TN30SE25.001
[[Page 46858]]
Proposed Reporting
KDC would be required to submit an annual draft summary report on
all construction activities and marine mammal monitoring results to
NMFS within 90 days following the end of construction or 60 calendar
days prior to the requested issuance of any subsequent IHA for similar
activity at the same location, whichever comes first. The draft summary
report would include an overall description of construction work
completed, a narrative regarding marine mammal sightings, and
associated raw PSO data sheets (in electronic spreadsheet format).
Specifically, the report must include:
Dates and times (begin and end) of all marine mammal
monitoring;
Construction activities occurring during each daily
observation period, including: (a) how many and what type of piles were
driven or removed and the method (i.e., impact, vibratory, DTH); and
(b) the total duration of time for each pile (vibratory driving) or
number of strikes for each pile (impact driving);
PSO locations during marine mammal monitoring; and
Environmental conditions during monitoring periods (at
beginning and end of PSO shift and whenever conditions change
significantly), including Beaufort sea state and any other relevant
weather conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance.
Upon observation of a marine mammal, the following information must
be reported:
Name of PSO who sighted the animal(s) and PSO location and
activity at the time of the sighting;
Time of the sighting;
Identification of the animal(s) (e.g., genus/species,
lowest possible taxonomic level, or unidentified), PSO confidence in
identification, and the composition of the group if there is a mix of
species;
Distance and bearing of each observed marine mammal
relative to the pile being driven or removed for each sighting;
Estimated number of animals (min/max/best estimate);
Estimated number of animals by cohort (e.g., adults,
juveniles, neonates, group composition, etc.);
Animal's closest point of approach and estimated time
spent within the estimated harassment zone(s);
Description of any marine mammal behavioral observations
(e.g., observed behaviors such as feeding or traveling), including an
assessment of behavioral responses thought to have resulted from the
activity (e.g., no response or changes in behavioral state such as
ceasing feeding, changing direction, flushing, or breaching);
Number of marine mammals detected within the estimated
harassment zones, by species; and
Detailed information about implementation of any
mitigation (e.g., shutdowns and delays), a description of specified
actions that ensured, and resulting changes in behavior of the
animal(s), if any.
If no comments are received from NMFS within 30 days after the
submission of the draft summary report, the draft report would
constitute the final report. If KDC received comments from NMFS, a
final summary report addressing NMFS' comments would be submitted
within 30 days after receipt of comments.
Reporting Injured or Dead Marine Mammals
In the event that personnel involved in KDC's activities discover
an injured or dead marine mammal, KDC would report the incident to the
NMFS Office of Protected Resources (OPR)
([email protected], [email protected]) and to the
Alaska Regional Stranding Coordinator (877-925-7773) as soon as
feasible. If the death or injury was clearly caused by the specified
activity, KDC would immediately cease the specified activities until
NMFS is able to review the circumstances of the incident and determine
what, if any, additional measures are appropriate to ensure compliance
with the IHA. KDC would not resume their activities until notified by
NMFS. The report would include the following information:
Description of the incident;
Environmental conditions (e.g., Beaufort sea state,
visibility);
Description of all marine mammal observations in the 24
hours preceding the incident;
Photographs or video footage of the animal(s) (if
equipment is available).
Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
Species identification (if known) or description of the
animal(s) involved;
Condition of the animal(s) (including carcass condition if
the animal is dead);
Observed behaviors of the animal(s), if alive; and
General circumstances under which the animal was
discovered.
Negligible Impact Analysis and Determination
NMFS has defined 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). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any impacts or responses (e.g., intensity, duration),
the context of any impacts or responses (e.g., critical reproductive
time or location, foraging impacts affecting energetics), as well as
effects on habitat, and the likely effectiveness of the mitigation. We
also assess the number, intensity, and context of estimated takes by
evaluating this information relative to population status. Consistent
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338,
September 29, 1989), the impacts from other past and ongoing
anthropogenic activities are incorporated into this analysis via their
impacts on the baseline (e.g., as reflected in the regulatory status of
the species, population size and growth rate where known, ongoing
sources of human-caused mortality, or ambient noise levels).
To avoid repetition, the discussion of our analysis applies to all
the species listed in table 12, given that the anticipated effects of
this activity on these different marine mammal stocks are expected to
be similar. There is little information about the nature or severity of
the impacts, or the size, status, or structure of any of these species
or stocks that would lead to a different analysis for this activity.
Pile driving for installation and removal, and DTH activities
associated with the proposed Project, as outlined previously, have the
potential to disturb or displace marine mammals. Specifically, the
specified activities may result in take in the form of Level A
harassment and/or Level B harassment from underwater sounds generated
from pile driving installation and removal. Potential takes could occur
if individuals of these species are present in zones ensonified above
the thresholds for Level A harassment or
[[Page 46859]]
Level B harassment identified above when these activities are underway.
Given the nature of the proposed activities, NMFS does not
anticipate serious injury or mortality due to KDC's proposed project,
even in the absence of required mitigation. The Level A harassment
zones identified in table 14 are based upon an animal exposed to
vibratory pile driving, impact pile driving, and DTH pile installation
for periods ranging from up to 15 minutes for impact driving per day,
up to 120 minutes for vibratory driving/removal per day), and up to 960
minutes for DTH per day. Exposures of this length are, however,
unlikely for vibratory driving/removal and DTH pile installation
scenarios, given marine mammal movement throughout the area. Even
during impact driving scenarios, an animal exposed to the accumulated
sound energy would likely only experience limited AUD INJ at the lower
frequencies where pile driving energy is concentrated.
As stated in the Proposed Mitigation section, KDC would implement
shutdown zones that equal or exceed many of the Level A harassment
isopleths shown in table 14. Take by Level A harassment is proposed for
seven marine mammal species (eight stocks). This is precautionary to
account for the potential that an animal could enter and remain within
the area between a Level A harassment zone and the shutdown zone for
long enough to be taken by Level A harassment. Additionally, in some
cases, this precaution would account for the possibility that an animal
could enter a shutdown zone without detection, given the various
obstructions along the shoreline, and remain in the Level A harassment
zone for a duration long enough to be taken by Level A harassment
before being observed and a shutdown occurring. That said, any take by
Level A harassment is expected to arise from, at most, a small degree
of AUD INJ because animals would need to be exposed to higher levels
and/or longer duration than are expected to occur here to incur any
more than a small degree of AUD INJ. Additionally, and as noted
previously, some subset of the individuals that are behaviorally
harassed could also simultaneously incur some small degree of TTS for a
short duration of time. Because of the small degree anticipated, any
AUD INJ or TTS potentially incurred here is not expected to adversely
affect an animal's individual fitness, let alone annual rates of
recruitment or survival.
For all species and stocks, take is expected to occur within a
limited, confined area (adjacent to the project site) of the stock's
range. The intensity and duration of take by Level A harassment and
Level B harassment would be expected to be minimized through the
proposed mitigation measures described herein. Furthermore, the amount
of take proposed for authorization is small compared to the relative
stock's abundance, even assuming that every take for any particular
species could wholly occur to individuals of an individual stock.
Behavioral responses of marine mammals to pile driving, pile
removal, and DTH at the project site, if any, are expected to be mild,
short-term, and temporary. Given that the installation of 18 permanent
piles and 20 temporary piles would occur over 14 days in total (9 for
permanent piles, 5 for temporary piles), and that the removal of 12
existing piles and 20 temporary piles would occur over 4 and 5 days,
respectively, (all of which may not necessarily be consecutive), any
harassment is expected to be temporary and intermittent. Marine mammals
within the Level B harassment zones may not show any visual cues they
are disturbed by activities or they could become alert, avoid the area,
leave the area, or display other mild responses that are not
observable, such as changes in vocalization patterns. Additionally,
many of the species present in region would only be present temporarily
based on seasonal patterns or during active transit between other
habitats. Most likely, during pile driving, individuals would be
expected to move away from the sound source and be temporarily
displaced from the areas of pile driving. However, this reaction has
been observed primarily associated with impact pile driving. While
vibratory driving associated with the proposed project may produce
sound at distances of many kilometers from the project site, thus
overlapping with some likely less-disturbed habitat, the project site
itself is located in a busy harbor, and the majority of sound fields
produced by the specified activities are close to the harbor. Animals
disturbed by project sounds would be expected to avoid the area and use
nearby higher-quality habitats. Pinnipeds in the area would have the
ability to haul-out to avoid the activities (noting that the known
haul-outs are located much further away from the project area) and no
in-air harassment is anticipated from the construction activities.
The potential for harassment is minimized by implementing the
proposed mitigation measures. During all impact driving, implementation
of soft-start procedures and monitoring of established shutdown zones
by trained and qualified PSOs shall be required, significantly reducing
any possibility of injury. Given sufficient notice through soft-start
(for impact driving), marine mammals are expected to move away from an
irritating sound source before it becomes potentially injurious.
Any impacts on marine mammal prey that would occur during KDC's
proposed activities would have, at most, short-term effects on foraging
of individual marine mammals, and likely no effect on the populations
of marine mammals as a whole. Indirect effects on marine mammal prey
during the construction are expected to be minor, and these effects are
unlikely to cause substantial effects on marine mammals at the
individual level, with no expected effect on annual rates of
recruitment or survival.
The area likely impacted by the project is relatively small
compared to the available habitat in the surrounding waters of
Southeast Alaska and Tongass Narrows. Although Tongass Narrows is part
of an identified BIA for feeding humpback whales (NOAA, 2023; Wild et
al., 2023), the timing of the BIA (May through September) may only
minimally overlap with the proposed timing of the in-water construction
(January through May), depending on when activities end (i.e., early
May, late May). Additionally, humpback foraging efforts within Tongass
Narrows are likely comparatively low due to the lower value of the
habitat in the immediate area (Wild et al., 2023), as evidenced by the
typically low occurrence of humpback whales in the area. Finally, there
is no ESA-designated critical habitat in the area for humpback whales.
In addition, it is unlikely that minor noise effects in a small,
localized area of habitat would have any effect on the reproduction or
survival of any individuals, much less the stocks' annual rates of
recruitment or survival. In combination, we believe that these factors,
as well as the available body of evidence from other similar
activities, demonstrate that the potential effects of the specified
activities would have only minor, short-term effects on individuals. As
already said, the specified activities are not expected to impact rates
of recruitment or survival; therefore, these effects would not be
expected to result in population-level impacts.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect any of the species
or stocks through effects on annual rates of recruitment or survival:
[[Page 46860]]
No serious injury or mortality is anticipated or proposed
for authorization;
Any Level A harassment exposures are anticipated to result
in slight AUD INJ (i.e., of a few decibels) within the lower
frequencies associated with pile driving;
The anticipated incidents of Level B harassment would
consist of, at worst, temporary modifications in behavior that would
not result in fitness impacts to individuals;
The area affected by the specified activity is very small
relative to the overall habitat ranges of all species, does not include
any rookeries, does not include ESA-designated critical habitat, and
only temporally overlaps with the southeast Alaska humpback whale
feeding BIA for a minimal amount of time in May, depending on when the
activities are expected to be completed (i.e., early May, late May);
Effects on species that serve as prey for marine mammals
from the activities are expected to be short-term and, therefore, any
associated impacts on marine mammal feeding are not expected to result
in significant or long-term consequences for individuals, or to accrue
to adverse impacts on their populations;
Although Steller sea lions and harbor seals are known to
haul-out, these haul-out locations are located over 7.55 km (4.69 mi)
to 30 km (18.6 mi) away from the proposed project site (depending on
the species), which is outside of the ensonified zone;
The project area is located in an industrialized and
commercial marina; and
The proposed mitigation measures, such as employing
vibratory driving to the maximum extent practicable, soft-starts, and
shutdowns, are expected to reduce the effects of the specified activity
to the least practicable adverse impact level.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the proposed monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from the proposed activity will have a negligible impact on
all affected marine mammal species or stocks.
Small Numbers
As noted previously, only take of small numbers of marine mammals
may be authorized under sections 101(a)(5)(A) and (D) of the MMPA for
specified activities other than military readiness activities. The MMPA
does not define small numbers and so, in practice, where estimated
numbers are available, NMFS compares the number of individuals taken to
the most appropriate estimation of abundance of the relevant species or
stock in our determination of whether an authorization is limited to
small numbers of marine mammals. When the predicted number of
individuals to be taken is fewer than one-third of the species or stock
abundance, the take is considered to be of small numbers (see 86 FR
5322, January 19, 2021). Additionally, other qualitative factors may be
considered in the analysis, such as the temporal or spatial scale of
the activities.
NMFS is proposing to authorize incidental take by Level A
harassment (in some cases) and/or Level B harassment of eight species
(consisting of 11 stocks) of marine mammals. No mortality or serious
injury has been requested, nor is it anticipated to occur from the
activities described herein. The maximum number of instances of takes
by Level A harassment and Level B harassment proposed, relative to the
best available population abundance, is less than one-third for all
species and stocks potentially impacted (see table 12).
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS preliminarily finds that small
numbers of marine mammals would be taken relative to the population
size of the affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
In order to issue an IHA, NMFS must find that the specified
activity will not have an ``unmitigable adverse impact'' on the
subsistence uses of the affected marine mammal species or stocks by
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50
CFR 216.103 as an impact resulting from the specified activity: (1)
that is likely to reduce the availability of the species to a level
insufficient for a harvest to meet subsistence needs by: (i) causing
the marine mammals to abandon or avoid hunting areas; (ii) directly
displacing subsistence users; or (iii) placing physical barriers
between the marine mammals and the subsistence hunters; and (2) that
cannot be sufficiently mitigated by other measures to increase the
availability of marine mammals to allow subsistence needs to be met.
Alaska Natives have historically hunted sea lions and harbor seals
in Southeast Alaska for thousands of years. Since surveys of harbor
seals and sea lion subsistence hunting in Alaska began in 1992, there
has been a noticeable decline in the number of households, which
undertake hunting and harvesting of harbor seals, while the number of
households undertaking hunting and harvesting activities on sea lions
has remained at consistently low levels (Wolfe et al., 2013).
Specifically in the Clarence Strait, harvest data indicates that the
average annual harvest in the years 2004-2008 of 164 harbor seals and
an average annual harvest in the years 2011-2012 of 40 harbor seals
(summarized in Muto et al., 2016 from Wolfe et al., 2013). In 2012, the
last recorded marine mammal harvest, the community of Ketchikan had an
estimated subsistence take of 22 harbor seals and 0 Steller sea lions
(Wolfe et al., 2013).
Given all of this information, NMFS agrees with KDC's preliminary
determination that the proposed project is not likely to adversely
affect the availability of any marine mammal species/stocks that would
traditionally be used for subsistence purposes, or would affect any
subsistence harvest in the region because of the following reasons:
The proposed construction activities are spatially
localized within a discrete area that has been previously developed
(i.e., the Ketchikan Berth IV dock site);
The proposed activities are expected to be temporary in
nature;
KDC would be required to implement mitigation measures
that minimize any disturbance to marine mammals in the action area,
including traditionally harvested species;
NMFS expects that most of the effects on marine mammals
would not rise above behavioral impacts (i.e., Level B harassment) and
would be temporary in nature and any impacts that would rise to the
threshold to cause PTS (i.e., Level A harassment) would occur on a
small group of animals (refer back to table 12); and
No serious injury or mortality is expected to result from
the project activities, therefore, the project would not result in a
signify ant change to the availability of subsistence resources.
Based on the description of the specified activity, the measures
described to minimize adverse effects on the availability of marine
mammals for subsistence purposes, and the proposed mitigation and
monitoring measures, NMFS has preliminarily determined that there will
not be an unmitigable adverse impact on subsistence uses from KDC's
proposed activities.
[[Page 46861]]
Endangered Species Act
Section 7(a)(2) of the ESA of 1973 (16 U.S.C. 1531 et seq.)
requires that each Federal agency ensures that any action it
authorizes, funds, or carries out is not likely to jeopardize the
continued existence of any endangered or threatened species or result
in the destruction or adverse modification of designated critical
habitat. To ensure ESA compliance for the issuance of IHAs, NMFS
consults internally whenever we propose to authorize take for
endangered or threatened species, in this case with the NMFS Alaska
Regional Office (AKRO).
NMFS is proposing to authorize the take of the Mexico-North Pacific
stock of humpback whales, which are listed as threatened under the ESA.
The NMFS Office of Protected Resources has requested the initiation of
ESA section 7 consultation with AKRO for the issuance of this IHA. NMFS
would conclude the ESA consultation before reaching a determination
regarding the proposed authorization issuance.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to KDC for conducting the Ketchikan Berth IV Expansion
Project in Ketchikan, Alaska in the East Tongass Narrows, provided the
previously mentioned mitigation, monitoring, and reporting requirements
are incorporated. A draft of the proposed IHA can be found at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities.
Request for Public Comments
We request comment on our analyses, the proposed authorization, and
any other aspect of this notice of proposed IHA for the proposed
Ketchikan Berth IV Expansion Project. We also request comment on the
potential renewal of this proposed IHA as described in the paragraph
below. Please include with your comments any supporting data or
literature citations to help inform decisions on the request for this
IHA or a subsequent renewal IHA.
On a case-by-case basis, NMFS may issue a one-time, 1-year renewal
IHA following notice to the public providing an additional 15 days for
public comments when (1) up to another year of identical or nearly
identical activities as described in the Description of Proposed
Activity section of this notice is planned or (2) the activities as
described in the Description of Proposed Activity section of this
notice would not be completed by the time the IHA expires and a renewal
would allow for completion of the activities beyond that described in
the Dates and Duration section of this notice, provided all of the
following conditions are met:
A request for renewal is received no later than 60 days
prior to the needed renewal IHA effective date (recognizing that the
renewal IHA expiration date cannot extend beyond 1 year from expiration
of the initial IHA).
The request for renewal must include the following:
1. An explanation that the activities to be conducted under the
requested renewal IHA are identical to the activities analyzed under
the initial IHA, are a subset of the activities, or include changes so
minor (e.g., reduction in pile size) that the changes do not affect the
previous analyses, mitigation and monitoring requirements, or take
estimates (with the exception of reducing the type or amount of take).
2. A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
Upon review of the request for renewal, the status of the
affected species or stocks, and any other pertinent information, NMFS
determines that there are no more than minor changes in the activities,
the mitigation and monitoring measures will remain the same and
appropriate, and the findings in the initial IHA remain valid.
Dated: September 24, 2025.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2025-18907 Filed 9-29-25; 8:45 am]
BILLING CODE 3510-22-P