Skip to Content


Endangered Fish and Wildlife; Notice of Intent to Prepare an Environmental Impact Statement

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble


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


Notice of Public Scoping and Intent (NOI) to prepare an Environmental Impact Statement (EIS); request for written comments.


NMFS will be preparing an EIS to analyze the potential impacts of applying new criteria in guidelines to determine what constitutes a “take” of a marine mammal under the Marine Mammal Protection Act (MMPA) and Endangered Species Act (ESA) as a result of exposure to anthropogenic noise in the marine environment. This notice describes the proposed action and possible alternatives and also describes the proposed scoping process.


NMFS will hold 4 public meetings to obtain comments on the scope of issues to be addressed in the EIS. The locations of the meetings are San Francisco, CA; Seattle, WA; Boston, MA; and Silver Spring, MD. See Supplementary Information for Start Printed Page 1872meetings dates and locations. In addition to obtaining comments in the public scoping meetings, NMFS will also accept written and electronic comments. Comments must be received by March 14, 2005.


Written comments on the scope of the EIS and requests to participate in the public scoping meetings should be submitted to P. Michael Payne, Chief, Marine Mammal Conservation Division, Office of Protected Resources, NMFS (F/PR2), 1315 East-West Highway, Silver Spring, MD 20910. Written comments may also be submitted by email to or by facsimile (fax) to (301) 427-2581. Include in the subject line the following identifier: I.D. 060804F.

Start Further Info


Brandon Southall, Office of Protected Resources, NMFS, 1315 East-West Highway, Silver Spring, MD 20910; Telephone (301) 713-2322. Additional information is available at (​prot_​res/​PR2/​Acoustics_​Program). For information regarding the EIS process, contact Michael Payne at the above referenced contact information.

End Further Info End Preamble Start Supplemental Information


Meetings Dates and Locations

The San Francisco, CA scoping meeting: January 18, 2005, 5 p.m. - 8 p.m. The meeting location is Hilton Fisherman's Wharf, 2620 Jones Street, San Francisco, CA, 94133,

telephone: 415-885-4700.

The Seattle, WA scoping meeting: January 20, 2005,

5p.m. - 8p.m. The meeting location is NOAA's Western Regional Center, Building 9 Auditorium, 7600 Sand Point Way NE, Seattle, WA, 98115.

The Boston, MA scoping meeting: January 25, 2005,

5p.m. - 8p.m. The meeting location is the New England Aquarium, Conference Center, Central Wharf, Boston, MA 02110.

The Silver Spring, MD scoping meeting: January 27, 2005, 5p.m. - 8p.m. The meeting location is the NOAA's Auditorium, 1301 East West Highway, Silver Spring, MD 20910.


Section 3(18)(A) 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].

The National Defense Authorization Act, enacted in November 2003, altered the definition of marine mammal harassment for “military readiness activities” and “scientific research activities conducted by or on behalf of the Federal Government consistent with section 104 (c)(3)” of the MMPA, as follows:

(i) any act that injures or has the significant potential to injure a marine mammal or marine mammal stock in the wild [Level A harassment];

(ii) any act that disturbs or is likely to disturb a marine mammal or marine mammal stock in the wild by causing disruption of natural behavioral patterns, including, but not limited to, migration, surfacing, nursing, breeding, feeding, or sheltering, to a point where such behavioral patterns are abandoned or significantly altered [Level B harassment].

NMFS has been using generic sound exposure thresholds since 1997 to determine when an activity in the ocean that produces sound might result in impacts to a marine mammal such that a take by harassment might occur (an 'acoustic' take). NMFS is developing new science-based thresholds to improve and replace the current generic exposure level thresholds that have been used since 1997.

Proposed Action

NMFS will be proposing to replace the current Level A and Level B harassment thresholds with guidelines based on exposure characteristics that are derived from empirical data and are tailored to particular species groups and sound types. These guidelines will identify exposures levels and durations that may produce either temporary or permanent shifts in hearing sensitivity thereby providing a more scientific basis for defining the threshold levels that might result in marine mammal harassment. Such information would be of use to industry (oil and gas, marine construction), researchers, academic, government, military and shipping activities.

As currently envisioned, the noise exposure guidelines would be based on the following sets of criteria. They would divide marine mammals into five functional hearing groups: low-frequency cetaceans (all mysticetes or baleen whales); mid-frequency cetaceans (all odontocete species (dolphins and porpoises) not included in the low or high frequency groups); high-frequency cetaceans (harbor and Dall s porpoise, river dolphins); pinnipeds under water (seals, fur seals and sea lions); and pinnipeds out of water. Each of the functional hearing groups has somewhat different hearing capabilities. Consequently, frequency-specific thresholds are being developed based on what is known about these differences.

The criteria would also categorize all anthropogenic sounds into four different types: single pulses (brief sounds with a fast rise time); single non-pulses (all other sounds); multiple pulses in a series; and multiple non-pulses in a series. Each of the five functional hearing groups would then be paired against the four sound types resulting in a matrix of values. These values would represent the noise-exposure criteria that NMFS would use, at least in part, to guide determinations of when an anthropogenic sound results in an acoustic “take” by harassment under the MMPA or ESA for each of the different marine mammal hearing groups. All threshold values would be expressed in terms of either a sound pressure level value that the animal receives, or as a measure of exposure that incorporates both sound pressures and time as a dimension where it is appropriate. This is referred to as the sound exposure, or energy flux density level. Energy levels are not directly comparable to pressure levels because of the time dimension.

A number of assumptions will be made in developing the acoustic matrix of threshold levels. For example, in most cells within the matrix, the criteria assume that all species in a functional hearing group have the same threshold apply to all species in the group. In reality, some species are so different from others in their functional hearing group that separate threshold criteria are appropriate for them. Further, there are no direct data on the effects of many kinds of sounds on many species of marine mammals. For now, therefore, it is necessary to extrapolate making reasonably conservative criteria from existing data to cover cases of missing data. An example of an extrapolation is the use of data from dolphins or beluga whales for other cetaceans. Most data on the effects of noise on marine mammals come from mid-frequency dolphins, especially bottlenose dolphins and beluga whales. The results of studies on these species are applied directly to low- and high-frequency cetaceans (for which data are sparse or non existent) without adjustment. This substitution is likely conservative for low frequency cetaceans because the mid-frequency cetacean ear is almost certainly more sensitive. The substitution is also likely satisfactory for high-frequency cetaceans. In the absence of data for marine mammals, in some cases, data from terrestrial mammals are used in determining exposure criteria.

Start Printed Page 1873

Purpose of the Action

NMFS will prepare an EIS to assess the potential impacts of the proposed framework for developing and implementing science-based acoustic Atake@ criteria. The EIS will analyze the potential environmental impacts resulting from implementation of the proposed noise exposure criteria to determine acoustic-based harassment of marine mammals, and alternative noise exposure criteria.

The areas of interest for evaluation of environmental and socioeconomic effects will be U.S. and international waters.

Use of the Noise Exposure Criteria

The noise exposure criteria would be used to inform NMFS guidelines as to what characteristics of human sound exposure (e.g., exposure frequency, level, and duration) might result in harassment and constitute a Atake@ under the MMPA and ESA. For example, an acoustic “take” might be considered to have occurred whenever the sound that the animal receives exceeds the exposures defined by the criteria. The noise exposure criteria would also provide guidance with respect to what type of take might result from exposure to sound - one for Level A harassment and one for Level B harassment.

Scope of the Action

The scope of the EIS will identify and evaluate all relevant impacts, conditions, and issues associated with the proposed framework for the development and implementation of these criteria, and alternatives, in accordance with Council on Environmental Quality=s (CEQ) Regulations at 40 CFR parts 1500 - 1508, and NOAA=s procedures for implementing NEPA found in NOAA Administrative Order (NAO) 216-6, Environmental Review Procedures for Implementing the National Environmental Policy Act, dated May 20, 1999.

The EIS will analyze the potential environmental impacts of implementation of the proposed framework and noise exposure criteria to determine acoustic “takes” of marine mammals, and alternative frameworks for developing and implementing noise exposure criteria. The EIS must meet the requirements of NEPA and the analyses must also document compliance with the related environmental impact analysis requirements of other statutes and executive orders. These include, but are not limited to, the MMPA, Coastal Zone Management Act, ESA, and the Magnuson-Stevens Fishery Conservation and Management Act.


The EIS will consider several alternatives for determining the acoustic threshold at which both Level A and Level B harassment takes might occur: 1) maintaining the status quo (the no action alternative); 2) using a precautionary approach and very conservative interpretations of data on marine mammals based on considering human noise exposures relative to ambient noise conditions; 3) defining a Level A harassment take as that exposure which results in a temporary shift in hearing sensitivity (TTS) and a Level B harassment take as that exposure estimated to result in a 50 percent behavioral avoidance for each species or group of species; 4) defining Level A harassment take as that exposure which results in a Permanent Threshold Shift (PTS) minus 6 decibels (dB) and defining a Level B harassment take as a level 6 dB below that exposure estimated to causes TTS; 5) defining a Level A harassment take as noise exposure consistent with estimated PTS onset and a level B harassment take as TTS onset; and 6) defining a Level A harassment take as occurring at the PTS onset plus 6 dB and level B harassment take as 6 dB below the estimated point of PTS onset (see Table 1).

Table 1: Acoustic Criterion for each of the Proposed Alternatives

AlternativeLevel A CriterionLevel B Criterion
I (Status Quo)180 dBrms re: 1μPa160 dBrms re: 1μPa (impulse) 120 dBrms re: 1μPa (continuous)
IIHighest averagelowest possible natural ambientambient
IIITTS Onset50% Behavioral Avoidance
IVPTS Onset-6dBTTS Onset-6dB
VPTS OnsetTTS Onset
VIPTS Onset+6dBPTS Onset-6dB

Alternative I: A no action alternative would perpetuate the use of the existing thresholds for Level A harassment (sound pressure level of 180 dBrms re: 1μPa) (hereafter dB SPL), and Level B harassment (160 dB SPL for impulse noise and 120 dB SPL for continuous sound) that have been used for the past six years. The advantages of this alternative are that the public is familiar with this approach, and safety zones can easily be calculated from standard sound propagation models. A disadvantage is that this considers only the sound pressure level of an exposure but not its other attributes, such as duration, frequency, or repetition rate, all of which are critical for assessing impacts on marine mammals. For example, a sound of 181 dB SPL lasting for two seconds would be identified as a Level A harassment take, but a potentially more harmful sound of 179 dB SPL lasting two days is currently considered a Level B harassment take. It also assumes a consistent relationship between rms (root-mean-square) and peak pressure values for impulse sounds, which is known to be inaccurate under certain (many) conditions.

Alternative II: A second alternative is based on very conservative behavioral response data for marine mammals. Under this alternative takes would occur at the SPL at which the most sensitive species first begin to show a behavioral response. Level A harassment would occur if the received noise from a human source exceeded the highest average ambient noise level in the area of operation. Level B harassment would occur if the received noise from a human source exceeded the lowest possible ambient noise condition. Criteria based largely on behavioral responses to noise just above ambient level would be extremely conservative. Under this alternative, a behavioral response may, and behavioral avoidance would, constitute Level B harassment.

Alternative III: A third alternative would define a Level A harassment take as occurring at that level of exposure which results in a temporary loss of hearing sensitivity (TTS) but which is fully recoverable. This approach is also conservative because scientific experts in this field do not consider TTS to Start Printed Page 1874result in harm or injury because no irreversible cell damage is involved. A Level B harassment take would be defined as that level of noise exposure known or estimated to result in 50 percent behavioral avoidance of a sound source for each species or animal group. There are a small number of these types of empirical data available for certain conditions, but some of the level B criteria constructed in this manner would require extrapolations and assumptions, particularly in the above context of how biological significance is defined. Generally this alternative would be less conservative than the previous alternative.

Alternative IV: A fourth alternative would determine that a Level A harassment take occurs at that level of noise exposure which results in a permanent loss of hearing sensitivity (PTS) due to non-recoverable cell damage, minus some “safety” factor. This alternative would be more conservative than federal workplace standards for humans which permit exposures that result in some degree of PTS over a lifetime for some individuals. A doubling of absolute sound pressure magnitude (in μPa) represents a 6 dB increase in SPL. A proposed “safety” factor to ensure that exposures do not result in permanent injury is to set the Level A harassment criteria 6 dB below that noise exposure estimated to cause PTS onset for each animal group. The proposed Level B harassment take criteria for alternative 4 are those exposures resulting in TTS onset minus a “safety” factor of 6 dB.

Alternative V: A fifth alternative defines a Level A harassment take as noise exposures estimated to result in PTS onset and Level B harassment take as noise exposures consistent with TTS onset for each animal group. This alternative would allow Level A harassment criteria levels that are higher than either TTS (Alternative III) or PTS minus some safety factor (Alternative IV); Level A harassment criteria would be based on those exposures that are believed to result in irreversible tissue damage. The Level B harassment criteria under Alternative V would set the take threshold slightly higher than Alternative IV but considerably below those in Alternative 6.

Alternative VI: A sixth alternative defines a Level A harassment take based on estimated PTS onset (as in Alternatives 4 and 5), but requires a higher probability of exposed animals experiencing a meaningful change in hearing sensitivity above merely the onset of tissue injury, such as 6 dB of PTS. Under Alternative VI, Level B harassment take would be defined as exposures estimated as 6 dB below those required to cause PTS onset. This alternative would result in noise threshold levels that are greater than any of the other proposed alternatives.

The noise exposure criteria are based on research available for all species of marine mammals, plus some data from terrestrial mammals and humans. Using data from one species of mammals to set criteria for another species is acceptable for injury because the anatomy of the inner ear of all mammals is extremely similar. As an example, certain human hearing standards are based in part on extrapolations from the effects of noise on the chinchilla ear. Table 2 provides an example of noise exposure criteria that would result under each of the proposed alternatives for gray whales. Gray whales were selected as an example because some data on behavioral reactions exist and are used (in Alternative III), but setting criteria based on TTS or PTS rely on extrapolations from other cetacean species (Alternatives III-VI). The use of direct information combined with reasonable extrapolation is representative of how such criteria would be established under any of the alternatives.

Table 2: Example of Noise Exposure Criteria for Gray Whales for each of the Proposed Alternatives

AlternativeLevel A CriterionLevel B Criterion
I180 dBrms re: 1μPa160 dBrms re: 1μPa (impulse) 120 dBrms re: 1μPa (continuous)
IIBoth criteria variabledepending on environment
III195 dB re: 1μPa2 (s)160 dBrms re: 1μPa
IV209 dB re: 1μPa2 (s)189 dB re: 1μPa2 (s)
V215 dB re: 1μPa2 (s)195 dB re: 1μPa2 (s)
VI221 dB re: 1μPa2 (s)209 dB re: 1μPa2 (s)

Alternative I indicates the status quo criteria already in place. Alternative II criteria are established based on ambient noise conditions experienced by animals in the area of operation. Since these conditions may be dominated by either natural or human noise and are quite variable depending on many spatial and temporal factors, the criteria for determining both Level A and Level B harassment are variable depending on the operational environment.In Alternative III, the Level A criterion is set at noise exposures estimated to cause TTS [195 dB re: 1μPa2(s). This is the estimated point of TTS onset for cetaceans based on Finneran et al. (2002)]. For Alternative III, Level B criteria are based on behavioral avoidance data for migrating gray whales (Malme et al., 1983; 1984). These are, in fact, the same data upon which the status quo (Alternative I) Level B data are based.

An additional extrapolation is made in Alternative IV to estimate PTS. The level of noise exposure required to induce PTS in marine mammals is unknown, but may be estimated using the TTS onset data and extrapolations based on terrestrial mammals. Using the slope of the function relating increases in noise exposure and TTS, and using a relatively conservative estimate of PTS as 40 dB of TTS, it is estimated that an additional 20 dB of noise exposure is required above TTS onset to induce PTS. Thus, for Alternative IV, the Level A harassment criterion is estimated TTS onset (195 dB re: 1μPa2 (s)) plus 20 dB to equal PTS onset (215 dB re: 1μPa2(s)) minus 6 dB, or 209 dB re: 1μPa2 (s). The Level B harassment criterion for Alternative IV is estimated TTS onset (195 dB re: 1μPa2 (s)) minus 6 dB, or 189 dB re: 1μPa2 (s).

For Alternative V, the Level A harassment criterion is the estimated PTS onset (215 dB re: 1μPa2(s) as described above) and the Level B harassment criterion is estimated TTS onset (195 dB re: 1μPa2 (s)). In Alternative VI, the Level A harassment criterion is 6 dB above estimated PTS onset (or 221 dB re: 1μPa2(s)) while the Level B harassment criterion is 6 dB below estimated PTS onset (or, 209 dB re: 1μPa2 (s)).

Start Printed Page 1875

Public Involvement and the Scoping Process

NMFS' intent is to afford an opportunity for the public, including interested citizens and environmental organizations; any affected low-income or minority populations; affected local, state and Federal agencies; and any other agencies with jurisdiction or special expertise concerning the environmental impacts to be addressed in the EIS to participate in this process.

NMFS will hold public scoping meetings and accept oral and written comments (See ADDRESSES) to determine the issues of concern with respect to practical considerations involved in applying these criteria and to determine whether NMFS is addressing the appropriate range of alternatives. In addition to comments on other aspects of the scope of this EIS, NMFS is particularly interested in comments regarding real-world application of the science-based noise exposure criteria. The public, as well as Federal, state, and local agencies, are encouraged to participate in this scoping process. The dates and locations of these meetings appear in this Federal Register notice (See SUPPLEMENTARY INFORMATION).

NMFS is also seeking written comments on the scope of issues that should be addressed in the EIS. The agency also invites the public to submit data, new information, and comments by e-mail, mail, or fax (See ADDRESSES) identifying relevant environmental and socioeconomic issues to be addressed in the environmental analysis.

Start Signature

Dated: January 6, 2005.

P. Michael Payne,

Acting Director, Office of Protected Resources, National Marine Fisheries Service.

End Signature End Supplemental Information

[FR Doc. 05-525 Filed 1-6-05; 3:17 pm]