Incidental Takes of Marine Mammals During Specified Activities; Shallow Hazard and Site Clearance Surveys in the Chukchi Sea in 2008, 46774-46795 [E8-18199]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 73, Number 155 (Monday, August 11, 2008)]
[Notices]
[Pages 46774-46795]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E8-18199]



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Part III





Department of Commerce





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National Oceanic and Atmospheric Administration



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Incidental Takes of Marine Mammals During Specified Activities; Shallow 
Hazard and Site Clearance Surveys in the Chukchi Sea in 2008; Notice

Federal Register / Vol. 73, No. 155 / Monday, August 11, 2008 / 
Notices

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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XJ55


Incidental Takes of Marine Mammals During Specified Activities; 
Shallow Hazard and Site Clearance Surveys in the Chukchi Sea in 2008

ACTION: Notice of issuance of a marine mammal incidental take 
authorization.

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SUMMARY:  In accordance with provisions of the Marine Mammal Protection 
Act (MMPA) as amended, notification is hereby given that an Incidental 
Harassment Authorization (IHA) to take marine mammals, by Level-B 
harassment, incidental to conducting open water shallow hazard and site 
clearance surveys by ASRC Energy Service (AES) in the Chukchi Sea, has 
been issued for a period of one year from the IHA effective date.

DATES:  The authorization is effective from July 30, 2008, until 
September 25, 2008.

ADDRESSES:  Copy of the application, IHA, the Final Programmatic 
Environmental Assessment for Arctic Ocean Outer Continental Shelf 
Seismic Surveys - 2006 (2006 PEA) prepared by the Minerals Management 
Service (MMS), the 2008 Supplemental Environmental Assessment (SEA) for 
the Issuance of five IHAs for open water seismic surveys and shallow 
hazard and site clearance surveys in the Arctic, and/or a list of 
references used in this document may be obtained by writing to P. 
Michael Payne, Chief, Permits, Conservation and Education Division, 
Office of Protected Resources, National Marine Fisheries Service, 1315 
East-West Highway, Silver Spring, MD 20910-3225, or by telephoning one 
of the contacts listed here (see FOR FURTHER INFORMATION CONTACT).

FOR FURTHER INFORMATION CONTACT:  Shane Guan, Office of Protected 
Resources, NMFS, (301) 713-2289, ext 137 or Brad Smith, Alaska Region, 
NMFS, (907) 271-5006.

SUPPLEMENTARY INFORMATION:

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce to allow, upon request, the 
incidental, but not intentional, taking of marine mammals by U.S. 
citizens who engage in a specified activity (other than commercial 
fishing) within a specified geographical region if certain findings are 
made and either regulations are issued or, if the taking is limited to 
harassment, a notice of a proposed authorization is provided to the 
public for review.
    Authorization 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 certain subsistence uses, and if the permissible methods 
of taking and requirements pertaining to the mitigation, monitoring and 
reporting of such takings are set forth. NMFS has defined ``negligible 
impact'' in 50 CFR 216.103 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.''
    Section 101(a)(5)(D) of the MMPA established an expedited process 
by which citizens of the United States can apply for an authorization 
to incidentally take small numbers of marine mammals by harassment. 
Except with respect to certain activities not pertinent here, 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].
    Section 101(a)(5)(D) establishes a 45-day time limit for NMFS 
review of an application followed by a 30-day public notice and comment 
period on any proposed authorizations for the incidental harassment of 
marine mammals. Within 45 days of the close of the comment period, NMFS 
must either issue or deny the authorization.

Summary of Request

    On March 25, 2008, NMFS received an application from AES for the 
taking, by Level B harassment, of several species of marine mammals 
incidental to conducting shallow hazard and site clearance surveys in 
the Chukchi Sea for up to 100 days from approximately July 1, 2008 
until November 30, 2008. On June 26, 2008, AES notified NMFS that the 
proposed shallow hazard and site clearance survey could be finished 
before September 25, 2008, with a maximum of up to 60 days. The marine 
surveys would take place in the Chukchi Sea covering the area involved 
in MMS Lease Sale 193. The specific areas where the AES proposed 
shallow hazard and site clearance surveys would be are the Burger, 
Crackerjack, Ulu, and Caramel prospect sites in the Chukchi Sea. The 
marine surveys will be performed from a seismic vessel.
    Detailed information on the shallow hazard and seismic surveys can 
be found in the AES application and in the Federal Register notice for 
the proposed IHA published on April 28, 2008 (73 FR 22922) (hereinafter 
``FR Notice of Proposed IHA''). Except for the updated seismic activity 
period and specific locations, no changes have been made to the 
proposed activities.

Comments and Responses

    A FR Notice of Proposed IHA was published on April 28, 2008 (73 FR 
22922). During the 30-day public comment period, NMFS received comments 
from the Marine Mammal Commission (Commission), the California Gray 
Whale Coalition (CGWC); the Native Village of Point Hope (NVPH); the 
North Slope Borough (NSB); the Alaska Eskimo Whaling Commission (AEWC); 
the Center for Biological Diversity, Pacific Environment, Sierra Club, 
Natural Resources Defense Council and Alaska Wilderness League; Oceana 
and Ocean Conservancy; Dr. David E. Bain of the University of 
Washington; Dr. Richard Steiner of the University of Alaska; and one 
private citizen.

General Comments

    Comment 1: The Commission recommends that NMFS issue the IHA 
provided that (a) the proposed marine mammal mitigation and monitoring 
activities are carried out as described in NMFS' FR Notice of Proposed 
IHA; and (b) operations be suspended immediately if a dead or seriously 
injured marine mammal is found in the vicinity of the operations and 
the death or injury could have occurred incidental to those operations.
    Response: NMFS concurs with the Commission's recommendation and 
will require the immediate suspension of seismic activities if a dead 
or injured marine mammal has been sighted within an area where the 
Holder of the IHA deployed and utilized seismic airguns within the past 
24 hours.
    Comment 2: The NSB points out that the AES application was poorly 
written, and that it did not reference the primary literature but used 
the summary information presented in the SAR. The NSB also points out 
that the scientific name of beluga whales was misspelled and the 
scientific name of the northern right whale was incorrect in the AES 
application. In essence, the NSB states that the application does not 
provide readers with confidence that AES has an

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understanding of the background information or the need or expertise to 
conduct marine mammal monitoring or mitigation in association with the 
proposed site clearance or shallow hazard surveys.
    Response: Comment noted. NMFS reviewed the AES application and 
verified the information provided within. While information is lacking, 
NMFS conducted relevant research so that complete information is 
provided in the FR Notice of Proposed IHA. In addition, detailed and 
updated information on bowhead whales and other marine mammal species 
is provided in the MMS 2006 PEA, MMS 2007 draft PEIS, NMFS 2008 SEA, 
and the SAR, as referenced in the FR Notice of Proposed IHA.
    Comment 3: The NVPH, CBD, and NSB point out that neither NMFS, nor 
AES has identified the specific locations where AES plans to conduct 
its shallow hazard and site clearance surveys, except that its vessels 
would remain 40 km (25 mi) away from the Chukchi coast. The CBD further 
points out that NMFS did not provide specific dates of the proposed AES 
shallow hazard and site clearance surveys. As such, the CBD suggests 
NMFS should reject AES' application as incomplete and requests that 
NMFS reopen the public comment period for an additional 30 days. The 
NVPH requests that NMFS identify all of the areas where subsistence 
hunting occurs, and impose enforceable restrictions that would require 
AES to avoid such areas by a distance sufficient to prevent 
displacement of marine mammals.
    Response: At the time of the publication of the FR Notice of 
Proposed IHA, no information was available regarding the exact 
locations of the survey and the specific dates because AES was in the 
stage of securing its client(s) and therefore could not have known 
where seismic survey operations would occur in the Chukchi Sea. 
Nevertheless, NMFS was able to conduct an analysis of AES' proposed 
2008 open water seismic activities and its potential impacts on marine 
mammals and subsistence uses. NMFS' preliminary determination that the 
issuance of an IHA to AES would have a negligible impact on affected 
species or stocks of marine mammals and would result in no unmitigable 
adverse impact on the availability of such species or stock for taking 
for subsistence uses was based on information contained in the AES 
application, including overall area (i.e., the area denoted as LS 193 
in the Chukchi Sea), the period of the seismic operations (i.e., 
approximately July 1 - November 30, 2008), the acoustic equipment 
planned to be used for the surveys, marine mammal species and stocks 
that are likely to be found in the vicinity of the project area, and 
the proposed mitigation and monitoring measures.
    In addition, the MMPA and NMFS' implementing regulations provide a 
30-day comment period on a proposed IHA. Based upon the information 
contained in the FR Notice of Proposed IHA, NMFS believes that the 
comment period afforded the public with ample time to comment on AES' 
proposed seismic surveys, despite the fact that AES did not identify an 
exact location in which the proposed surveys would occur. At this time, 
the precise survey locations and operation timeframe have been 
identified (see Description of the Specified Activity section above). 
Therefore, the IHA issued to AES limits its 2008 open water shallow 
hazard and site clearance surveys within these areas.
    Finally, the areas and season where subsistence hunting occurs are 
described and analyzed in detail in the MMS 2007 EIS on Chukchi Sea 
Lease Sale 193, and NMFS has developed a list of mitigation measures 
that restrict seismic activities when the subsistence hunt occurs. For 
example, no seismic activities would be permitted before July 15 in the 
Chukchi Sea spring lead system. Also, as analyzed in the FR Notice of 
Proposed IHA, it is possible that small numbers of marine mammals could 
be temporarily displaced from their feeding areas as a result of the 
proposed shallow hazard and site clearance surveys. However, NMFS 
believes any displacement would constitute Level B behavioral 
harassment with the magnitude of displacement being relatively slight. 
NMFS does not believe the displacement of marine mammals would result 
in an unmitigable adverse impact to the availability of marine mammal 
species and/or stocks to subsistence uses because the AES would 
complete their seismic surveys before the fall bowhead hunting season, 
and it would not begin their operations prior to the completion of the 
late spring whale harvest, which is already over.
    In addition, NMFS understands that AES has developed a POC with the 
Native communities. The POC specifies measures AES would take to help 
ensure that any harassment of marine mammals resulting from the 
proposed activities will not have an unmitigable adverse impact on the 
availability of marine mammal species or stocks for taking for 
subsistence uses. NMFS will also require AES to comply with certain 
terms and conditions in the IHA to help ensure the availability of 
marine mammals for taking for subsistence uses. Please see description 
of the mitigation and monitoring measures below.
    Comment 4: The CBD and CGWC urge NMFS not to issue any take 
authorization to AES for the proposed activities unless and until the 
agency can ensure that mitigation measures are in place that truly 
avoid adverse impacts to all species and their habitats and only after 
full and adequate public participation has occurred and environmental 
review of the cumulative impacts of such activities on these species 
and their habitats has been undertaken. The CBD feels that the proposed 
IHA does not meet these standards and therefore violate the MMPA, ESA, 
NEPA, and other governing statutes and regulations.
    Response: NMFS does not agree with CBD's assessment. In its FR 
Notice of Proposed IHA, NMFS outlined in detail the proposed mitigation 
and monitoring requirements. The implementation of these measures will 
reduce the impacts of the proposed survey on marine mammals and their 
surrounding environment to the lowest level practicable, as required by 
the MMPA. The public was given 30 days to review and comment on these 
measures, in accordance with section 101(a)(5)(D) of the MMPA. NMFS has 
prepared a Supplemental EA to the 2006 MMS PEA. NMFS has fulfilled its 
obligations under NEPA by completing a SEA, which is not required to be 
available for public comment prior to its finalization. Additionally, 
NMFS completed a Biological Opinion in July, 2008, as required by 
section 7 of the ESA, which concluded that this action is not likely to 
jeopardize the continued existence of listed species or result in the 
destruction or adverse modification of critical habitat. Therefore, 
NMFS does not believe the issuance of an IHA to AES would result in a 
violation of the MMPA, ESA, NEPA, and other governing statutes and 
regulations.

Acoustics Impacts

    Comment 5: Citing studies on noise impacts to chinchillas 
(Henderson et al., 1991) and human noise exposure standards by the U.S. 
Occupational Safety Health Administration (OSHA), Dr. Bain states that 
``in humans, chronic exposure to levels of noise too low to generate a 
TTS can result in PTS.'' As OSHA standards require limiting human 
exposure to noise at 115 dBA above threshold to 15 minutes per day, Dr. 
Bain concludes that this level is equivalent to 145 dB re 1 microPa for 
killer whales.

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    Response: Although NMFS agrees that chronic exposure to noise 
levels that would not cause TTS could result in hearing impairment in 
the long-term, it is important to understand that such exposure has to 
be of a chronic and long-term nature. The OSHA standards for 
permissible exposure are based on daily impacts throughout an 
employee's career, while the noise exposure to seismic surveys by 
marine mammals is short-term and intermittent, as described in the FR 
Notice of Proposed IHA and in the MMS 2006 PEA. In addition, the 
reference Dr. Bain cites to (Henderson et al., 1991) does not address 
chronic noise impact to humans. The research by Henderson et al. (1991) 
focused on the applicability of the equal energy hypothesis (EEH) to 
impact (impulse) noise exposures on chinchillas, and the results 
indicated that hearing loss resulting from exposure to impact noise did 
not conform to the predictions of the EEH, which is the basis for OSHA 
standards for continuous noise exposure.
    Most importantly, Dr. Bain's extrapolation of 145 dB re 1 microPa 
for killer whale hearing safety from OSHA's 115 dBA is fundamentally 
flawed for three reasons:
    (1) The reference points when using decibel (dB) unit that address 
sound in air and in water are different. For airborne sounds, such as 
those by OSHA, the reference point is 20 microPa, while for underwater 
sounds, the reference point is 1 microPa. There are 26 dB differences 
between the values when different reference points are used for the 
same sound pressure, therefore, 115 dB re 20 microPa is 141 dB re 1 
microPa for the same sound pressure. So 115 dB re 20 microPa in air 
above human threshold (defined as 0 dB re 20 microPa in air) would be 
141 dB re 1 microPa underwater for the same sound pressure. Using the 
lowest threshold of 30 dB re 1 microPa as the killer whale hearing 
threshold, and assuming that noise impacts to killer whales are the 
same as for humans, one could extrapolate that continuous noise 
exposure of 171 dB re 1 microPa (141 dB over the 30 dB threshold) for 
15 minutes for killer whales would be equivalent to humans exposed to 
115 dB re 20 microPa for 15 minutes. Nevertheless, such extrapolation 
still leaves much uncertainty since marine mammals have a different 
mechanism for sound reception (Au, 1993; Richardson et al., 1005). Some 
of the most recent science have shown that for some odontocetes, the 
onset of TTS when exposed to impulse noise is much higher (Finneran et 
al., 2002) than NMFS' current thresholds.
    (2) The decibel values used by OSHA are expressed as broadband A-
weighted sound levels expressed in dBA. This frequency-dependent 
weighting function is used to apply to the sound in accordance with the 
sensitivity of the human ear to different frequencies. Thus, it is 
inappropriate to compare these values to an animal's hearing 
capability, including how an animal perceives sound in air (Richardson 
et al., 1995). For marine mammals, M-weighting functions have been 
suggested based on five different hearing functional groups to address 
different hearing sensitivities of different frequencies by each of the 
marine mammal groups (Southall et al., 2007).
    (3) Finally, the sound characteristic used in OSHA standards is 
continuous sound, while the seismic sound from the proposed shallow 
hazard and site clearance surveys is impulse sound, which by its very 
nature is not a continuous sound.
    Comment 6: Dr. Bain asserts that the zone of immediate risk of 
injury or death for marine mammals should be within the 150 - 215 dB re 
1 microPa contours and assumes that values can be extrapolated from 
terrestrial species. Dr. Bain supports his argument by stating that 
immediate injury may result from brief exposure to sound levels that 
are 120 to 140 dB above threshold in terrestrial mammals, and that 
marine mammals vary in their best sensitivity from killer whales at 
around 30 dB re 1 microPa (killer whale) to 60 dB re 1 microPa 
(phocids) and 75 dB re 1 microPa (otariids)
    Response: NMFS does not agree with Dr. Bain's assessment. As 
discussed in Response to Comment 4, the reference points when using 
decibel (dB) unit that address sound in air is 20 microPa, while in 
water the reference point is 1 microPa. Therefore, the decibel levels 
used to address injury in terrestrial mammals cannot be extrapolated to 
apply marine mammal species without adding a correction factor of 26 dB 
(see Richardson et al., 1995). Even so, plenty of controlled laboratory 
experiments on several marine mammal species (e.g., beluga whales, 
bottlenose dolphins, harbor seals, California sea lions, and northern 
elephant seals) in the past decade point out injuries (PTS) to marine 
mammals would probably occur at much higher sound exposure levels, far 
above the 180 and 190 dB re 1 microPa NMFS currently applies to protect 
cetaceans and pinnipeds from onset of Level A harassment (injury). (see 
review by Southall et al., 2007).
    Comment 7: Citing OSHA (2007) standards for human noise exposure 
standards, Nachtigall et al. (2003), and Henderson et al. (1991), Dr. 
Bain extrapolates that permanent injury to hearing from repeated 
exposure to noise at 120 dB re 1 microPa would occur to killer whales 
after being exposed for 8 hours.
    Response: NMFS does not agree with Dr. Bain's assessment as such an 
extrapolation is invalid. First, as discussed in Response to Comment 5, 
the reference point addressing sound levels or intensities in air, 
which is used by OSHA for the human noise exposure standards, is 
relative to 20 microPa, while the reference point used to address sound 
levels or intensities in water is relative to 1 microPa. These are 
fundamentally different acoustical measures and should not be confused. 
Second, as discussed in Response to Comment 5, the noise exposure 
standard unit used by OSHA is dBA, which is the weighted sound exposure 
level based on human hearing sensitivities, and is not suitable to be 
used in other animals which have very different hearing sensitivities 
across the spectrum. Third, the sound sources used by OSHA are based on 
continuous sound, as is the referenced paper by Nachtigall et al. 
(2003), while the sound sources from the proposed seismic surveys are 
impulse sounds. The prediction of acoustic injury from continuous noise 
exposure is not applicable to impulse noise exposure, as is shown in 
the referenced paper by Henderson et al. (1991); therefore, the 
extrapolation is invalid. Fourth, ambient noise levels at many shallow 
water areas could easily reach 120 dB re 1 microPa, coupled with surf 
and wave actions. If killer whales suffered from permanent hearing 
damage when exposed to this noise level for 8 hours as suggested by Dr. 
Bain, then most killer whales in the coastal areas would have no 
hearing left. The lab controlled experiments by Nachtigall et al. 
(2003), as cited by Dr. Bain, show that an Atlantic bottlenose dolphin 
exhibited TTS of an average 11 dB after being exposed to continued 
noise up to 179 dB re 1 microPa for 55 minutes, a much higher level 
than where Dr. Bain would consider TTS to occur. However, in the wild, 
animals are expected to avoid such intense noise levels, thus 
preventing onset of TTS. Finally, killer whales are not expected to 
occur frequently in the proposed Arctic shallow hazard and site 
clearance project area, so the risk to this species is minimal.
    Comment 8: Citing several papers on killer whales, harbor 
porpoises, and marbeled murrelets, Dr. Bain states that major behavior 
changes of these animals appear to be associated with received

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levels of around 135 dB re 1 microPa, and that minor behavioral changes 
can occur at received levels from 90 - 110 dB re 1 microPa or lower. 
Citing his own studies, Dr. Bain states that ``killer whales are 40% 
less likely to forage at all when vessels are nearby, perhaps because 
vessel noise masks echoes from prey, making the probability of foraging 
successfully negligible (Bain et al., 2006a; 2006b).'' In addition, Dr. 
Bain states that the threshold for effects on harbor porpoise is 90 dB 
re 1 microPa, for killer whale is 100 dB re 1 microPa, and for beluga 
whale is 153 dB re 1 microPa, which are all lower than the threshold 
used to estimate the takes. CBD also cited a study of Canadian beluga 
whales showing flight responses from ice-breakers at received sound 
levels as low as 94 dB.
    Response: NMFS does not agree with Dr. Bain and CBD's assessment. 
Although it is possible that marine mammals could react to any sound 
levels detectable above the ambient noise level within the animals' 
respective frequency response range, this does not mean that such 
animals would react in a biologically significant way. In addition, as 
discussed in Response to Comment 6, ambient noise levels in many of the 
world's ocean can easily exceed 90 dB re 1 microPa (Urick, 1983).
    According to experts on marine mammal behavior, the degree of 
reaction which constitutes a ``take,'' i.e., a reaction deemed to be 
biologically significant that could potentially disrupt the migration, 
breathing, nursing, breeding, feeding, or sheltering, etc. of a marine 
mammal is complex and context specific, and it depends on several 
variables in addition to the received level of the sound by the 
animals. These additional variables include, but are not limited to, 
other source characteristics (such as frequency range, duty cycle, 
continuous vs. impulse vs. intermittent sounds, duration, moving vs. 
stationary sources, etc.); specific species, populations, and/or 
stocks; prior experience of the animals (naive vs. previously exposed); 
habituation or sensitization of the sound by the animals; and behavior 
context (whether the animal perceives the sound as predatory or simply 
annoyance), etc. (Southall et al., 2007).
    The references cited by Dr. Bain and CBD in this comment address 
different source characteristics (continuous sound rather than impulse 
sound that are planned for the proposed shallow hazard and site 
clearance surveys) or species (killer whales and harbor proposes) that 
rarely occur in the proposed Arctic action area. No reference 
supporting the ``threshold for effects'' on beluga whales is provided 
by Dr. Bain. Much research regarding bowhead and gray whales response 
to seismic survey noises has been conducted in addition to marine 
mammal monitoring studies during prior seismic surveys. Detailed 
descriptions regarding behavior responses of these marine mammals to 
seismic sounds are available (e.g., Richardson et al., 1995; review by 
Southall et al., 2007), and are also discussed in this document.
    Comment 9: Dr. Bain states that sound sources are typically divided 
into continuous and pulsed categories, and that behavioral effects from 
pulsed sound are likely to be independent of the repetition rate and 
duty cycle, and depend primarily on the duration of the survey. Dr. 
Bain further states that intermittent pulses can result in continuously 
received noise when sound arrives via multiple paths, which Dr. Bain 
explains as ``sound that bounces between the bottom and the surface 
will take longer to reach an animal than sound traveling via a direct 
path,'' and that ``noise can mask signals for a brief period before and 
after it is received, meaning an almost continuous received noise can 
mask signals continuously.'' Dr. Bain concludes that ``the subbottom 
profilers proposed for use during the site clearance surveys, with the 
very short intervals between pulses, present a risk of continuous 
masking effects.''
    Response: NMFS does not agree with Dr. Bain's statement on ocean 
acoustics and his subsequent analysis and assessment regarding 
underwater sound propagation and its effects to marine mammals. Within 
the scientific community on ocean acoustics and bioacoustics, two types 
of sounds are traditionally recognized: transient sounds (sounds of 
relatively short duration) and continuous sounds (sounds that go on and 
on). Transient sounds can be further classified into impulsive (such as 
seismic airguns, explosives, pile driving) and non-impulsive (such as 
military tactic sonars) sounds (Richardson et al., 1995). Other 
researchers working on noise impacts to marine mammals classified sound 
types into a single pulse (such as a single explosive), multiple pulses 
(seismic airguns, pile driving), and nonpulses (ship, sonar) (Southall 
et al., 2007). A simple way to distinguish pulses sound from nonpulses 
(continuous sound included) is that the former have rapid rise-time in 
relation to its extremely short duration. As mentioned in Response to 
Comment 8, behavioral responses from marine mammals when exposed to 
underwater noise is complex and context specific, and often depend on 
the sound characteristics (such as received levels, duration, duty 
cycles, frequency, etc.) and other variables.
    NMFS agrees that the distinction between transient and continuous 
sounds is not absolute, as continuous sound from a fast moving vessel 
is often treated as transient sound in relation to a stationary or slow 
moving marine mammal. Further, the distinction between pulses and 
nonpulses is also not always clear as certain pulsed sound sources 
(e.g., seismic airguns and explosives) may become nonpulses at greater 
distances due to signal decay through reverberation and other 
propagation paths. However, Dr. Bain's statement that intermittent 
pulses can result in continuously received noise when sound arrives via 
multiple paths is unfounded. For a marine mammal exposed to noise, 
multipath propagation would expose the animal to the noise multiple 
times, usually each subsequent exposure with lower sound level due to 
loss of acoustic energy from surface and bottom reflections; however, 
the noise arriving via multipath propagation would not become 
continuous sound because the intervals between signals would always 
exist. In addition, noise cannot mask a signal before or after it is 
received by the animal. Noise masking of signals can only occur when 
the unwanted sound (noise) interferes with the signal when received by 
the animal, generally at similar frequencies (Richardson et al., 1995). 
Therefore, Dr. Bain's assessment that the subbottom profilers proposed 
for shallow hazard and site clearance surveys would cause continuous 
masking effects to marine mammals is not supported.
    Comment 10:Dr. Bain states that one characteristic of pulsed 
sources is known as ``time-bandwidth'' product, and he explains that it 
is ``any sound with a finite duration (that is, any real-world sound) 
contains additional frequencies to the nominal frequency. That is, 
pulsed sources that nominally have a frequency that is too high to 
hear, may, in fact, be audible, as the source will contain lower 
frequencies that are detectable.''
    Response: NMFS does not agree with Dr. Bain's statement that high 
frequency pulsed sources nominally contain additional frequencies that 
are audible. The high frequency pulsed sources are expected to operate 
within their frequency range, although some mechanical noise at lower 
frequencies may be produced as a byproduct during the operation. The 
mechanical noise associated with acoustic equipment is

[[Page 46778]]

expected to be low intensity and is not expected to result in 
harassment of marine mammals. Furthermore, the term ``time-bandwidth 
product'' is generally used in signal process, which is irrelevant to 
the proposed Arctic seismic survey.
    Comment 11: Dr. Bain states that the directionality of the sources 
and whether they are on during turns would also affect the ensonified 
area.
    Response: All acoustic sources are downward directional, thus no 
additional ensonified area would result during turns.
    Comment 12: The CBD argues that NMFS analysis of the various high-
energy sound sources on marine mammals is deficient, with NMFS for the 
most part simply asserting that the sound generated by these sources is 
outside the hearing range of most marine mammals. The CBD further 
states that even NMFS acknowledges that odontocetes such as beluga 
whales can in fact hear these sounds.
    Response: NMFS does not agree with the CBD statement as it does not 
have scientific basis. In the FR Notice of the Proposed IHA, NMFS 
stated that the 445 kHz frequency band from the Klein System 3000 dual 
frequency digital side-scan sonar is outside any marine mammal species' 
hearing range, therefore, there would be no effect to marine mammals 
when this frequency is chosen. High frequency sounds above 200 kHz are 
clearly outside the hearing ranges for any marine mammals, which is 
well accepted among marine mammal bioacousticians (Richardson et al., 
1995; Southall et al., 2007). In addition, NMFS never acknowledged that 
odontocetes such as beluga whales can hear these sounds (CBD did not 
provide any reference to support its statement.) Furthermore, the sound 
generated by various side-scan sonars operated at the frequency of 120 
kHz and beyond produce signals above the hearing ranges for mysticetes, 
such as bowhead, gray, humpback, and minke whales (Richardson et al., 
1995; Southall et al., 2007).
    Comment 13: Citing Weilgart (2007), the CGWC states that seismic 
surveys can raise low-frequency noise over vast areas for more than a 
month, exposing large portions of a cetacean population to chronic 
noise. Citing Tyack (1988), the CGWC further states that avoidance 
behavior has been reported for gray whales in response to decibels 
great than 120 dB for continuous noise and 160 - 170 dB for pulsed 
sounds. In addition, the CGWC points out that playback of sounds from a 
Bell 212 turbine helicopter projected at random intervals of 10 seconds 
to 2 minutes showed significant course changes in gray whales in 
apparent avoidance of the sounds. Finally, the CGWC states that 
reactions to noise by gray whales are more pronounced on their 
breeding/calving grounds (Malme et al., 1983; 1984), and that gray 
whales were displaced for greater than 5 years from one of their 
breeding lagoons in response to industrial sounds (Jones et al., 1994).
    Response: NMFS does not agree with CGWC's ``one size fits all'' 
statement that ``seismic surveys can raise low-frequency noise over 
vast areas for more than a month, exposing large portions of a cetacean 
population to chronic noise.'' The degree and number of cetaceans, or 
any marine mammal species that can be exposed to a seismic survey 
depends on the duration of the survey, the intensity of the airgun 
source, and the density of cetacean population, or other marine 
mammals, in the vicinity of the survey area.
    NMFS agrees with CGWC's comments that behavioral modification of 
many marine mammals starts when exposed to pulsed sounds at 160 - 170 
dB, as cited in Tyack (1988), which is consistence with NMFS current 
criteria for Level B behavioral harassment of 160-dB when exposed to 
pulsed sounds, and 120-dB when exposed to continuous sounds. The 
signals produced by airguns and other acoustic equipment for the 
proposed AES shallow hazard and site clearance survey are all pulsed 
sounds.
    Finally, the proposed survey area in the Arctic Ocean is not gray 
whale breeding/calving grounds, so there will be no effect to this 
species' breeding/calving activities from the proposed activity.
    Comment 14: The CGWC states that when gray whales were on their 
feeding grounds, Malme et al. (1986) estimated that there was a 50 
percent probability of gray whale avoidance when the average pulse 
level of the received noise was approximately 173 dB and a 10 percent 
probability of avoidance at 163 dB.
    Response: Comment noted. Though some gray whales (10 percent) may 
be temporarily affected by seismic surveys when exposed to received 
level at 163 dB as referenced by Malme et al. (1986), NMFS does not 
consider this effect to be significant for the following reasons: (1) 
the proposed shallow hazard and site clearance survey area is in the 
Chukchi Sea and is not a primary feeding ground for gray whales. The 
majority of gray whales feed on amphipods in shallow coastal waters in 
the Bering Sea which is not located near the proposed seismic survey 
area; and (2) a 160-dB safety zone will be established requiring shut-
down of airguns when a congregation of 12 or more bowhead or gray 
whales is sighted during the AES seismic activities.
    Comment 15: Citing NMFS (2002), Weller et al. (2006a; 2006b), and 
IWC (2007), the CGWC states that noise has been thought to at least 
contribute to some species' decline or lack of recovery.
    Response: Comment noted. However, since the CGWC did not provide 
the full reference of the citation, NMFS is not able to verify its 
statement. Nevertheless, for the proposed AES shallow hazard and site 
clearance survey, NMFS has conducted a through analysis of the 
potential impacts from seismic noise to marine mammals in its FR Notice 
of Proposed IHA. More extensive analyses are also provided in the MMS 
2006 PEA, the MMS 2007 draft PEIS and the 2008 SEA. As stated in this 
document, NMFS finds that the impact of conducting the shallow hazard 
and site clearance surveys in Chukchi Sea may result, at worst, in a 
temporary modification in behavior of small numbers of certain species 
of marine mammals.

MMPA Comments

    Comment 16: The CBD and NSB state that since NMFS has not 
promulgated any regulations related to shallow hazard and site 
clearance surveys under the MMPA, and because such surveys and 
associated activities carry the real potential of injury or death to 
marine mammals, neither an IHA nor an LOA can be issued for the AES' 
proposed activities.
    Response: NMFS does not agree with the CBD and NSB's statement. 
Section 101(a)(5)(D) of the MMPA authorizes Level A (injury) harassment 
and Level B (behavioral) harassment takes. While NMFS' regulations 
indicate that a LOA must be issued if there is a potential for serious 
injury or mortality, NMFS does not believe that AES' shallow hazard and 
site clearance survey require issuance of a LOA. As explained 
throughout this Federal Register Notice of the Proposed IHA, it is 
highly unlikely that marine mammals would be exposed to sound pressure 
levels (SPLs) that could result in serious injury or mortality. The 
best scientific information indicates that an auditory injury is 
unlikely to occur as apparently sounds need to be significantly greater 
than 180 dB for injury to occur (Southall et al., 2007).
    NMFS has determined that exposure to several seismic pulses at 
received levels near 200 205 dB (rms) might result in slight temporary 
threshold shift

[[Page 46779]]

(TTS) in hearing in a small odontocete, assuming the TTS threshold is a 
function of the total received pulse energy. Received levels of 200 205 
dB or more from the loudest acoustic device would be restricted to a 
radius of no more than 5 m (16 ft) around a seismic vessel. AES' airgun 
array is considered to be of small size. For baleen whales, while there 
are no data, direct or indirect, on levels or properties of sound that 
are required to induce TTS, there is a strong likelihood that baleen 
whales (bowhead and gray whales) would avoid the approaching airguns 
(or vessel) before being exposed to levels high enough for there to be 
any possibility of onset of TTS. For pinnipeds, information indicates 
that for single seismic impulses, sounds would need to be higher than 
190 dB rms for TTS to occur while exposure to several seismic pulses 
indicates that some pinnipeds may incur TTS at somewhat lower received 
levels than do small odontocetes exposed for similar durations. 
Consequently, NMFS has determined that it would be lawful to issue an 
IHA to AES for the 2008 seismic survey program.
    Comment 17:The CBD states that it referenced the scientific 
literature linking seismic surveys with marine mammal stranding events 
in its comments to MMS on the 2006 Draft PEA and in comments to NMFS 
and MMS on the 2007 DPEIS. The CBD further states that NMFS' failure to 
address these studies and the threat of serious injury or mortality to 
marine mammals from seismic surveys renders NMFS' conclusory 
determination that serious injury or morality will not occur from AES' 
activities arbitrary and capricious.
    Response: The MMS briefly addressed the humpback whale stranding in 
Brazil on page PEA-127 in the 2006 Final PEA. Marine mammal strandings 
are also discussed in the MMS 2007 DPEIS. A more detailed response to 
the cited strandings has been provided in several previous IHA issuance 
notices for seismic surveys (e.g., 73 FR 40512, July 15, 2008). 
Additional information has not been provided by CBD or others regarding 
these strandings. As NMFS has stated, the evidence linking marine 
mammal strandings and seismic surveys remains tenuous at best. Two 
papers, Taylor et al. (2004) and Engel et al. (2004), reference seismic 
signals as a possible cause for a marine mammal stranding. Taylor et 
al. (2004) noted two beaked whale stranding incidents related to 
seismic surveys. The statement in Taylor et al. (2004) was that the 
seismic vessel was firing its airguns at 1300 hrs on September 24, 
2004, and that between 1400 and 1600 hrs, local fishermen found live-
stranded beaked whales some 22 km (12 nm) from the ship's location. A 
review of the vessel's trackline indicated that the closest approach of 
the seismic vessel and the beaked whales' stranding location was 33 km 
(18 nm) at 1430 hrs. At 1300 hrs, the seismic vessel was located 46 km 
(25 nm) from the stranding location. What is unknown is the location of 
the beaked whales prior to the stranding in relation to the seismic 
vessel, but the close timing of events indicates that the distance was 
not less than 33 km (18 nm). No physical evidence for a link between 
the seismic survey and the stranding was obtained. In addition, Taylor 
et al. (2004) indicates that the same seismic vessel was operating 500 
km (270 nm) from the site of the Galapagos Island stranding in 2000. 
Whether the 2004 seismic survey caused two beaked whales to strand is a 
matter of considerable debate (see Cox et al., 2004). NMFS believes 
that scientifically, these events do not constitute evidence that 
seismic surveys have an effect similar to that of mid-frequency 
tactical sonar. However, these incidents do point to the need to look 
for such effects during future seismic surveys. To date, follow-up 
observations on several scientific seismic survey cruises have not 
indicated any beaked whale stranding incidents.
    Engel et al. (2004), in a paper presented to the International 
Whaling Commission (IWC) in 2004 (SC/56/E28), mentioned a possible link 
between oil and gas seismic activities and the stranding of eight 
humpback whales (seven off the Bahia or Espirito Santo States and one 
off Rio de Janeiro, Brazil). Concerns about the relationship between 
this stranding event and seismic activity were raised by the 
International Association of Geophysical Contractors (IAGC). The IAGC 
(2004) argues that not enough evidence is presented in Engel et al. 
(2004) to assess whether or not the relatively high proportion of adult 
strandings in 2002 is anomalous. The IAGC contends that the data do not 
establish a clear record of what might be a ``natural'' adult stranding 
rate, nor is any attempt made to characterize other natural factors 
that may influence strandings. As stated previously, NMFS remains 
concerned that the Engel et al. (2004) article appears to compare 
stranding rates made by opportunistic sightings in the past with 
organized aerial surveys beginning in 2001. If so, then the data are 
suspect.
    Second, strandings have not been recorded for those marine mammal 
species expected to be harassed by seismic in the Arctic Ocean. Beaked 
whales and humpback whales, the two species linked in the literature 
with stranding events with a seismic component are either extralimital 
or not located in the Chukchi Sea where shallow hazard and site 
clearance survey would occur. Moreover, NMFS notes that in the Arctic, 
marine mammal observation and monitoring have been conducted by the 
industry during periods of industrial activity (and by MMS during times 
with no activity). No strandings or marine mammals in distress have 
been observed during these surveys; nor reported by NSB inhabitants. 
Finally, if bowhead and gray whales react to sounds at very low levels 
by making minor course corrections to avoid seismic noise and 
mitigation measures require AES to ramp-up the seismic array to avoid a 
startle effect, strandings are highly unlikely to occur in the Arctic 
Ocean. Ramping-up of the array will allow marine mammals the 
opportunity to vacate the area of ensonification and thus avoid any 
potential injury or impairment of their hearing capabilities. In 
conclusion, NMFS does not expect any marine mammals will incur serious 
injury or mortality as a result of AES' shallow hazard and site 
clearance survey in the Chukchi Sea in 2008.
    Comment 18: The CBD states that NMFS failed to adequately specify 
AES' activities and impacts of vessels because neither AES' application 
nor NMFS' FR Notice of the Proposed IHA mention the various transit 
routes through U.S. waters in the Bering, Chukchi and/or Beaufort Seas 
that these vessels associated with AES' surveys would take.
    Response: The specified activity that has been proposed and for 
which an IHA has been requested is the use of seismic airguns to 
conduct oil and gas exploration. While the support vessels play a role 
in facilitating seismic operations, NMFS does not expect these 
operations to result in the incidental take of marine mammals. Since 
these support vessels are typically slow-moving, any risk of vessel 
collisions with marine mammals is expected to be minimal. Moreover, 
normal shipping and transit operations do not rise to a level requiring 
an authorization under the MMPA. To require IHAs and LOAs for standard 
shipping would reduce the ability of NMFS to review activities that 
have a potential to cause harm to marine mammal populations.
    Comment 19: The AEWC and NSB state that a ``small take'' finding 
cannot be supported with actual data for the proposed AES shallow 
hazard and site

[[Page 46780]]

clearance survey, therefore, placing NMFS in the position of having to 
make an arbitrary decision. In addition, the CBD states that NMFS did 
not make the distinction between ``small number'' and ``negligible 
impact'' while making the decision in the FR Notice of the Proposed 
IHA.
    Response: NMFS does not agree with the CBD's statement. The 
analysis provided in the FR Notice of the Proposed IHA clearly 
described in detail the numbers of bowhead, gray, and beluga whales, 
and ringed and bearded seals that may be potentially taken by Level B 
harassment as a result of the seismic operations in the Chukchi Sea. 
(Take estimates for pinnipeds have since been revised based on the 160-
dB rms threshold.) As clearly stated in the aforementioned Federal 
Register notice, take numbers of these species represent 0.06, 0.06, 
and 0.6 percent of the western Arctic stock of bowhead (population 
estimated at 10,545), eastern North Pacific stock of gray (population 
estimated at 18,178), and eastern Chukchi stock of Beluga whales 
(population estimated at 3,710), respectively; and 3.96 and 0.438 
percent of the Alaska stocks of ringed (population estimated at 249,000 
in the Chukchi Sea) and bearded seal (population estimated at 250,000 - 
300,000 in the Bering and Chukchi Seas) populations within the Chukchi 
Sea, respectively. Although no take number was estimated for humpback, 
fin, minke, and killer whales, harbor porpoises, and spotted and ribbon 
seals in the vicinity of the project area due to their rare presence 
based in the Chukchi Sea, NMFS believes that the harassment of these 
species would be much less likely than those of bowhead and beluga 
whales and ringed and bearded seals. NMFS believes that the numbers for 
all affected species are small relative to their stock size. Separate 
detailed analyses on the levels of take by noise exposure and 
cumulative impacts to these marine mammal species and stocks from a 
wide spectrum in the past, current, and foreseeable future were also 
conducted and described in the aforementioned Federal Register notice, 
the MMS 2006 PEA, and NMFS 2008 SEA. These analyses led NMFS to 
conclude that while behavioral modifications, including temporarily 
vacating the area during the project period may be made by these 
species to avoid the resultant visual and acoustic disturbance, NMFS 
nonetheless found that this action would result in no more than a 
negligible impact on the affected marine mammal species and/or stocks. 
NMFS also found that the proposed action would not have an unmitigable 
adverse impact on the availability of such species or stocks for taking 
for subsistence uses. Please refer to the Federal Register notice (73 
FR 22922, April 28, 2008), MMS 2006 PEA, and NMFS 2008 SEA for a 
detailed description of the analysis.
    Comment 20: The CBD points out that AES only provided estimates for 
exposure to sounds greater than 170 dB re 1 microPa (rms) for 
pinnipeds, and that NMFS has in the previous IHAs rejected this 
threshold. The CBD further points out that neither NMFS nor ASRC 
provide any estimate of how many pinnipeds would be exposed to sounds 
greater than 160 dB.
    Response: To be consistent with NMFS' Level B behavioral harassment 
criteria for pinnipeds, NMFS will continue to use 160 dB re microPa as 
the threshold of onset for Level B behavioral harassment, as noted in 
this document. The estimated numbers of pinnipeds that could be exposed 
to SPLs by AES' activities have been recalculated based on NMFS' 
application of the 160-dB rms threshold and are described in this 
Federal Register notice (see response to comment 19). Nevertheless, it 
is important to note that even with the 160 dB criteria, NMFS expects 
that only small numbers of pinnipeds would be exposed to seismic noises 
that could cause Level B behavioral harassment. In addition, research 
by Moulton and Lawson (2002) showed that most pinnipeds exposed to 
seismic sounds lower than 170 dB do not visibly react to that sound, 
and, therefore, pinnipeds are not likely to react to seismic sounds 
unless they are greater than 170 dB re 1 microPa (rms). While the 
number of potential exposures of pinnipeds at 170 dB is smaller than 
that at 160 dB, the overall environmental effect of received sound 
levels at 170 dB versus 160 dB is expected to be similar based on the 
best available science.
    Comment 21: The CBD and NSB state that NMFS' estimates of the 
number of marine mammals that may be harassed based on the assumption 
that sounds below 160 dB re 1 microPa (rms) do not constitute 
harassment is incorrect because an activity can constitute harassment 
if it has the ``potential'' to affect marine mammal behavior. In 
addition, the CBD argues that 160 dB threshold for belugas is similarly 
flawed, as it points out in previous IHA notices, NMFS has acknowledged 
the impacts of sounds on beluga even at significant distances from a 
sound source (up to 20 km).
    Response: NMFS does not agree with CBD and NSB's statement. As 
stated in the MMPA, Level B harassment is defined as any act of 
pursuit, torment, or annoyance which ``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.'' Activities that 
affect marine mammal behavior briefly but not cause disruption of 
behavioral patterns are not considered ``takes.''
    In addition, in regard to impacts to marine mammal behaviors, 
distance is not the only factor that counts. The received levels at 
which marine mammals are affected are related to a number of factors 
including source levels, distances, and acoustic propagation pathways. 
The particular example CBD brought up regarding the seismic surveys by 
the National Science Foundation used airgun arrays with total discharge 
volume of 2,840 in\3\, while the proposed AES shallow hazard and site 
clearance survey would only use an airgun array with total discharge 
volume of 40 in\3\. The different source levels determine the 
ensonified zone where marine mammals, including beluga whales, would be 
impacted.
    Comment 22: The CBD and NSB state that NMFS has no idea of the 
actual population status of several of the species subject to the 
proposed IHA. For example, in the most recent Stock Assessment Reports 
(SARs) prepared pursuant to the MMPA, NMFS acknowledges it has no 
accurate information on the status of ribbon, spotted, bearded, and 
ringed seals. CBD and NSB both indicate that without these data, NMFS 
cannot conclude that surveys which will harass untold numbers of 
individuals of each species would have no more than a ``negligible 
impact'' on the stocks.
    Response: As required by the MMPA implementing regulations at 50 
CFR 216.102(a), NMFS has used the best scientific information available 
in making its determinations required under the MMPA. The Alaska SAR 
provides population estimates based on past survey work conducted in 
the region, and the SAR shows that based on the most recent 
information, all of these Alaska stocks of ice seal species have robust 
populations. The proposed survey by AES is not expected to have adverse 
impacts on ice seals. The activity will last for approximately 60 days 
in the open-water environment of the Chukchi Sea, where bearded and 
spotted seals are found only occasionally.
    In addition, it is expected that approximately 9,850 and 1,094 
ringed and bearded seals would be affected by

[[Page 46781]]

Level B behavioral harassment as a result of the proposed shallow 
hazard and site clearance surveys, respectively, and that these take 
umbers represent 3.96 and 0.438 percent of the Alaska stocks of ringed 
and bearded seal populations within the Chukchi Sea, respectively. 
Although spotted and ribbon seals could also be taken by Level B 
behavioral harassment as a result of the proposed marine surveys in the 
Chukchi Sea, the probability of take is very low since their presence 
is very rare within the proposed project area. Nonetheless, NMFS 
believes their take numbers would be much lower as compared to those 
marine mammals whose take numbers were calculated.
    Comment 23: Citing research on long term adverse effects to whales 
and dolphins from whale watching activities (Trites and Bain, 2000; 
Bain, 2002; Lusseau et al., 2006), Dr. Bain states that Level B 
behavioral harassment could be the primary threat to cetacean 
populations.
    Response: Although NMFS agrees that long-term, persistent, and 
chronic exposure to Level B harassment could have a profound and 
significant impact on marine mammal populations, such as described in 
the references cited by Dr. Bain, however, those examples do not 
reflect the impacts of seismic surveys to marine mammals for the 
proposed AES project. First, whale watching vessels are intentionally 
targeting and making close approaches to cetacean species so the 
tourists onboard can have a better view of the animals. Some of these 
whale/dolphin watching examples cited by Dr. Bain occurred in the 
coastal waters of the Northwest Pacific between April and October and 
for extended periods of time (``[r]ecreational and scientific whale 
watchers were active by around 6 a.m., and some commercial whale 
watching continued until around sunset.'') Thus multiple vessels have 
been documented to be in relatively close proximity to whales for about 
12 hours a day, six months a year, not counting some ``out of season'' 
whale watching activities and after dark commercial filming efforts. In 
addition, noise exposures to whales and dolphins from whale watching 
vessels are probably significant due to the vessels' proximity to the 
animals. To the contrary, the proposed 2008 open water shallow hazard 
and site clearance surveys, along with other potential four seismic 
activities and existing industrial operations in the Chukchi and 
Beaufort Seas, do not intentionally approaching marine mammals in the 
project areas. The two areas situate in a much larger Arctic Ocean 
Basin which is far away from most human impacts. Therefore, the adverse 
effects from each activity are remote and spread farther apart, as 
analyzed in the MMS 2006 PEA and draft EIS. The proposed seismic 
activities would only be conducted between July and November for a 
maximum of 100 days, weather permitting. In addition, although studies 
and monitoring reports from previous seismic surveys have detected 
Level B harassment of marine mammals, such as avoidance of certain 
areas by bowhead and beluga whales during the airgun firing, no 
evidence suggests that such behavioral modification is biologically 
significant or non-negligible (Malme et al., 1986; 1988; Richardson et 
al., 1987; 1999; Miller et al., 1999; 2005), as compared to those 
exposed by chronic whale watching vessels cited by Dr. Bain. Therefore, 
NMFS believes that potential impacts to marine mammals in the Arctic by 
shallow hazard and site clearance surveys would be limited to Level B 
harassment only, and due to the limited scale and remoteness of the 
projects in relation to a large area, such adverse effects would not 
accumulate to the point where biologically significant effects would 
realized.
    Comment 24: Dr. Bain states that changes in behavior resulting from 
noise exposure could lead to indirect injury in marine mammals in the 
wild. He presented several examples to suggest that marine mammals 
repeatedly exposed to Level B behavioral harassment could result in 
Level A takes: (1) Gas bubble lesions in beaked whales due to 
acoustically mediated bubble growth or rapid ascent by animals after 
deep diving; (2) a minke whale and harbor porpoises were observed 
traveling at high speed during exposure to mid-frequency sonar in Haro 
Strait in 2003, and that exhaustion from rapid flight could lead to 
heart or other muscle damage, which could cause mortality; (3) citing 
MMS' (2004) Environmental Assessment on Proposed Oil and Gas Lease Sale 
195 in the Beaufort Sea Planning Area (OCS EIS/EA MMS 2004-028) that 
feeding requires a prey density of 800 mg/m3 and his own observation, 
Dr. Bain is concerned displacement from high productive feeding areas 
would negatively affect individual whales, and that small cetaceans 
such as harbor porpoises would face a risk of death if they are unable 
to feed for periods as short as 48 - 72 hours; (4) individual killer 
whales have been observed splitting their pod when frightened by sonar, 
and that other killer whales' separation from their social units has 
resulted in death; (5) TTS may lead to harm as a minke whale was nearly 
struck by a research vessel in the area where one had been observed 
fleeing mid-frequency sonar; and (6) impaired auditory ability may 
increase predation as white-sided dolphins were attacked by killer 
whales due to the noise of the research vessel caused the approach of 
killer whales undetected by the dolphins.
    Response: NMFS agrees that it is possible that changes in behavior 
or auditory masking resulting from noise exposure could lead to injury 
in marine mammals under certain circumstances in the world, such as 
those examples/hypotheses raised by Dr. Bain. However, it is not likely 
that received sound pressure levels (SPLs) from the shallow hazard and 
site clearance surveys would drastically cause changes in behavior or 
auditory masking in marine mammals in the vicinity of the proposed 
action area. First, marine mammals in the aforementioned examples and 
hypotheses were exposed to high levels of non-pulse intermittent sounds 
such as the military sonar, which has been shown to cause flight 
activities (e.g., Haro Strait killer whales); and continuous sounds 
such as the vessel, which could cause auditory masking when animals are 
closer to the source. The sources produced by the acoustic equipment 
and airguns for the proposed shallow hazard and site clearance surveys 
are impulse sounds used in seismic profiling, bathymetry, and seafloor 
imaging. Unlike military sonar, seismic pulses have an extremely short 
duration (tens to hundreds milliseconds), and relatively long intervals 
(several seconds) between pulses. Therefore, the sound energy levels 
from these acoustic equipment and small airguns are far lower in a 
given time period. Second, the intervals between each short pulse would 
allow the animals to detect any biologically significant signals, and 
thus avoid or prevent auditory masking. In addition, NMFS requires 
mitigation measures to ramp up acoustic sources at a rate of no more 
than 6 dB every 5 minutes. This ramp up would prevent marine mammals 
from being exposed to high level noises without warning, thereby 
eliminating the possibility that animals would dramatically alter their 
behavior (i.e. from a ``startle'' reaction). NMFS also believes that 
long-term displacement of marine mammals from a feeding area is not 
likely because the seismic vessel is constantly moving, and the maximum 
160-dB ensonified radius is about 4 km, which would make an ensonified 
zone of approximately 50 km2 at any given moment, which is a small area 
compared to the Chukchi

[[Page 46782]]

Sea. In reality, NMFS expects the 160-dB ensonified zone to be smaller 
due to absorption and attenuation of acoustic energy in the water 
column.
    Comment 25: Citing that the difference between takes by subsistence 
harvest and potential biological removal (PBR) of the Western Arctic 
stock bowhead whales is about 28 individuals whales, or less than 0.3 
percent of the population, Dr. Bain is concerned that the cumulative 
effects of multiple seismic surveys would not need to be very large to 
push takes over PBR for bowheads.
    Response: NMFS does not agree with Dr. Bain's assessment. None of 
the five proposed 2008 open water Arctic seismic surveys and shallow 
hazard and site clearance surveys is expected to result in any Level A 
harassment (i.e., injury) or mortality. As analyzed in the NMFS 2008 
supplemental environmental assessment (SEA) for the issuance of five 
Arctic seismic surveys and shallow hazard and site clearance surveys, 
all incidental takes of marine mammals are expected to be Level B 
behavioral harassment (NMFS, 2008). Therefore, no PBR would be applied 
for the proposed AES seismic activities and other 2008 seismic 
activities in the Chukchi and Beaufort Seas.
    Comment 26: Citing MMS 2006 Programmatic Environmental Assessment 
(MMS 2006 PEA) and the MMS 2007 draft Programmatic Environmental Impact 
Statement (DEIS) for seismic surveys in the Arctic Ocean, Dr. Bain 
states that he supports the mitigation measures established in these 
documents that no more than 12 cow/calf pairs and aggregation of 
feeding or resting bowheads are within the area to be ensonified by 120 
dB and 160 dB, respectively. The CBD also states that the monitoring of 
a 120 dB safety zone for bowhead cow/calf pairs and monitoring of a 160 
dB safety zone for large groups of bowhead or gray whales (>12 
individuals) were required by NMFS in 2006 and were practicable. The 
CBD states that the failure to require such conditions, or at least 
analyze it, violates the MMPA. Dr. Bain presumes that these numbers 
(using 120 and 160 dBs) reflect the difference between takes allocated 
to hunters and the PBR for the stock. Dr. Bain further suggests that 
this number be applied to all seismic activities combined, not 
individual seismic surveys, thus, if four seismic surveys occur 
concurrently, no single survey should be allowed to affect the 
migration of more than 3 cow/calf pairs or 3 aggregation of feeding or 
resting bowhead whales.
    Response: First, the additional mitigation measures in the MMS 2006 
PEA and the MMS 2007 draft PEIS, as well as in the 2007 NMFS SEA for 
the issuance of an IHA to Shell Offshore Inc. for its open water 
seismic surveys conducted in the Chukchi and Beaufort Seas in 2007, 
establish safety (shut-down) zones of 120 dB re 1 microPa for an 
aggregation of four or more bowhead cow/calf pairs and 160 dB re 1 
microPa for an aggregation of 12 or more bowhead or gray whales, not 12 
cow/calf pairs as Dr. Bain states in his comment. The rationale for 
this cautious and conservative approach when addressing the 120-dB and 
160-dB safety zones is clearly stated in the MMS 2006 PEA. These 
additional mitigation and monitoring measures were identified through 
the analyses to further reduce the potential for adverse environmental 
impacts and, depending on the scope of seismic-survey activities, could 
be adopted as requirements for seismic-survey-related marine mammal 
incidental take authorizations. With respect to CBD's concern that 
these measures were ``practicable'' in 2006, NMFS has re-evaluated the 
practicability of requiring aerial monitoring to the 120-dB isopleth in 
the Chukchi. NMFS has determined that it is not practicable to conduct 
aerial monitoring to the 120-dB isopleth because aerial surveys have 
currently been determined to be impracticable due to lack of adequate 
landing facilities, the prevalence of fog and other inclement weather 
in that area, thereby resulting in safety concerns. Additionally, these