Taking of Marine Mammals Incidental to Specified Activities; Open Water Seismic Operations in Cook Inlet, Alaska, 17118-17133 [E7-6488]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 72, Number 66 (Friday, April 6, 2007)]
[Notices]
[Pages 17118-17133]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E7-6488]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[I.D. 030607A]


Taking of Marine Mammals Incidental to Specified Activities; Open 
Water Seismic Operations in Cook Inlet, Alaska

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

ACTION:  Notice of issuance of two incidental harassment 
authorizations.

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SUMMARY:  In accordance with provisions of the Marine Mammal Protection 
Act (MMPA) as amended, notification is hereby given that Incidental 
Harassment Authorizations (IHAs) to take marine mammals, by harassment, 
incidental to conducting seismic operations in the northwest portion of 
Cook Inlet, Alaska, have been issued to ConocoPhillips Alaska, Inc. 
(CPAI) and Union Oil Company of California (UOCC) for a period between 
mid-March and mid-June, 2007.

DATES:  The authorization for CPAI is effective from March 30 until May 
31, 2007; and the authorization for UOCC is effective from May 1 until 
June 15, 2007.

ADDRESSES:  A copy of the application, IHA, Environmental Assessment 
(EA), 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) 271-3023.

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 small numbers of marine 
mammals by U.S. citizens who engage in a specified activity (other than 
commercial fishing) within a specified geographical region if certain 
findings are made and either regulations are issued or, if the taking 
is limited to harassment, notice of a proposed authorization is 
provided to the public for review.
    An 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 subsistence uses and that the permissible methods of 
taking and requirements pertaining to the mitigation, monitoring and 
reporting of such taking 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 
small numbers of marine mammals. Within 45 days of the close of the 
comment period, NMFS must either issue or deny issuance of the 
authorization.

Summary of Request

    On October 6 and on October 12, 2006, NMFS received applications 
from CPAI and UOCC, respectively, requesting Incidental Harassment 
Authorizations (IHAs) for the possible harassment of small numbers of 
the Cook Inlet beluga whale (Delphinapterus leucas), Steller lions 
(Eumetopias jubatus), Pacific harbor seals (Phoca vitulina richardsi), 
harbor porpoises (Phocoena phocoena), and killer whales (Orcinus orca) 
incidental to conducting open water seismic operations in portions of 
Cook Inlet, Alaska. A detailed description of these activities was 
published in the Federal Register on January 5, 2007 (72 FR 536). No 
change has been made to these proposed activities.
    Both proposed operations use an ocean-bottom cable (OBC) system to 
conduct seismic surveys. OBC seismic surveys are used in waters that 
are too shallow for the data to be acquired using a marine-streamer 
vessel and/or too deep to have static ice in the winter. The proposed 
operations would be active 24 hours per day, but the airguns would only 
be active for 1 - 2 hours during each of the 3 - 4 daily slack tide 
periods. The source for the proposed OBC seismic surveys would be a 
900-in\3\ BOLT airgun array situated on the source vessel, the 
Peregrine Falcon. The array would be made up of 2 sub-arrays, each with 
2 3-airgun clusters separated by 1.5 m (4.9 ft) off the stern of the 
vessel. One cluster will consist of 3 225-in\3\ airguns and the second 
cluster

[[Page 17119]]

will have 3 75-in\3\ airguns. During seismic operations, the sub-arrays 
will fire at a rate of every 10 - 25 seconds and focus energy in the 
downward direction as the vessel travels at 4 - 5 knots (4.6 - 5.8 
mph). Source level of the airgun array is 249 dB re 1 microPa at 1 m (0 
- peak), and the dominant frequency range is 8 - 40 Hz.
    The geographic region for the seismic operation proposed by CPAI 
encompasses a 25 mi\2\ (65 km\2\) area in northwestern Cook Inlet, 
paralleling the shoreline from just offshore of the Beluga River south 
for about 6 km (3.7 miles). The approximate boundaries of the region of 
the proposed project area are 61[deg]09.473'N, 151[deg]11.987'W; 
61[deg]16.638'N, 151o02.198'W; 61[deg]12.538'N, 150[deg]49.979'W; and 
61[deg]05.443'N, 151o00.165'W. Water depths range from 0 to 24 m (80 
ft). There will be a 1.6 km (1 mile) setback of operations from the 
mouth of the Beluga River to comply with Alaska Department of Fish and 
Game (ADFG) restrictions. The proposed seismic operations would occur 
from mid March depending on the time of ice breakup, and last until 
mid-May, 2007.
    The geographic region for the activity proposed by UOCC encompasses 
a 28.2 km\2\ (10.9 square miles) area in northwestern Cook Inlet, 
paralleling the shoreline offshore of Granite Point, and extending from 
shore into the inlet to an average of about 1.6 km (1 mile). The 
approximate boundaries of the region of the proposed project area are 
61[deg]00.827'N, 151[deg]24.071'W; 61[deg]02.420'N, 151[deg]15.375'W; 
61[deg]00.862'N, 150[deg]15.313'W; and 61[deg]57.979'N, 
151[deg]23.946'W. There are no major rivers flowing into the open water 
seismic project area. Water depths range from 0 to 18 m (60 ft). The 
proposed seismic operations would begin as early as May 1 and end no 
later than June 15, 2007.

Comments and Responses

    A notice of receipt and request for 30-day public comment on the 
applications and proposed authorizations was published on January 5, 
2007 (72 FR 536). During the 30-day public comment period, NMFS 
received the following comments from the Marine Mammal Commission 
(Commission), the Humane Society of the United States (HSUS), the 
Center for Biological Diversity (CBD), the Whales and Dolphin 
Conservation Society (WDCS), the Animal Welfare Institute (AWI), CPAI, 
the Center for Regulatory Effectiveness (CRE), and one private citizen.

General Comments

    Comment 1: The Commission recommends that NMFS issue the IHAs 
subject to the following stipulations:
    (1) The applicants be required to institute monitoring and 
mitigation measures sufficient to afford the potentially affected 
marine mammals species adequate protection from sources of disturbance, 
including disturbance of behavior;
    (2) The period of observation be extended from 15 to 30 minutes 
before it is assumed that an animal has moved beyond the safety zone;
    (3) Observations be carried out during all ramp-up procedures to 
gather data regarding the effectiveness of ramp-up as a mitigation 
measures; and
    (4) Operations be suspended immediately if a dead or seriously 
injured marine mammals is found in the vicinity of the operations and 
the death or injury could be attributable to the applicants' 
activities. Any suspension should remain in place until NMFS has (a) 
reviewed the situation and determined that further deaths or serious 
injuries are unlikely or (b) issued regulations authorizing such takes 
under section 101(a)(5)(A) of the MMPA.
    Response: NMFS agrees with the Commission's comments and 
recommendation that the applicants must institute monitoring and 
mitigation measures sufficient to afford the potentially affected 
marine mammal species adequate protection from sources of disturbance, 
including disturbance of behavior. As an additional measure of marine 
mammal monitoring, NMFS requires that CPAI conducting aerial monitoring 
of Cook Inlet beluga whales in the vicinity of the project area during 
seismic surveys between mid-March and mid-May (see Monitoring Section 
later in this document). The aerial surveys would determine the 
presence and relative numbers of belugas between east Susitna River and 
North Foreland and determine the location of belugas relative to 
seismic operations. No aerial monitoring is required for seismic 
operations by UOCC since the proposed project area and time would not 
have a relative high number of beluga whales.
    NMFS also agrees with the Commission that the duration of pre-
operation monitoring be extended to 30 minutes to make sure that no 
marine mammals are in the safety zone before the initiation of airgun 
firing. As is standard under IHAs, observation would also be conducted 
during all ramp-up procedures to ensure the effectiveness of ramp-up as 
a mitigation measure.
    NMFS further agrees with the Commission that seismic operations 
must be suspended immediately if a dead or seriously injured marine 
mammal is found in the vicinity of the project area and the death or 
injury of the animal could be attributable to the applicants' 
activities. This requirement is a conditions in the IHA.
    Comment 2: CPAI urges NMFS to proceed with the authorization as 
proposed in the Federal Register notice (72 FR 536, January 5, 2007) 
and to require only the mitigation measures, monitoring and reporting 
procedures listed in the notice, including: (1) limiting the time and 
frequency of the operations and the use of airguns; (2) establishment 
of safety zones; (3) vessel speed and course alteration; (4) power-down 
procedures; (5) shut down procedures; (6) ramp-up procedures; (7) use 
of qualified NMFS-approved vessel-based marine mammal observers (MMOs); 
and (8) report of submission after the end of the project.
    Response: The Federal Register notice (72 FR 536), published on 
January 5, 2007, provides a detailed description of the proposed 
seismic operations by CPAI and UOCC in upper Cook Inlet, the 
anticipated impacts to marine mammal species and/or stocks and their 
habitat within the project area, the potential effects on the 
subsistence harvest of these marine mammal species and/or stocks, and a 
list of proposed monitoring and mitigation measures to reduce the 
potential impacts that would result from the proposed actions. A 
thorough review by NMFS biologists of these projects, impacts, and 
monitoring and mitigation measures led NMFS to reach a preliminary 
determination the proposed projects, would result in no more than a 
negligible impact on such species or stocks, and would not have an 
unmitigable adverse impact on the availability of such species or 
stocks for subsistence uses, provided that all monitoring and 
mitigation measures are carried out.
    After careful consideration, NMFS decided to add an additional 
monitoring measure to require CPAI to also conduct aerial monitoring of 
Cook Inlet beluga whales within its project area off Beluga River in 
upper Cook Inlet to ensure beluga whales are not displaced from their 
normal habitat. Please refer to the Monitoring Section later in this 
document for a detailed description of CPAI's aerial monitoring plan.
    In addition, CAPI and UOCC are required to conduct pre-survey 
monitoring of marine mammals for 30 minutes to ensure that the safety 
zone

[[Page 17120]]

is free of marine mammals prior to initiating airgun firing, and that 
seismic operations must be suspended immediately if a dead or seriously 
injured marine mammals is found in the vicinity of the operations and 
the death or injury could be attributable to the applicants' 
activities. All these requirements are conditions of the IHAs.

MMPA Concerns

    Comment 3: CBD states that NMFS did not make the distinction 
between ``small number'' and ``negligible impact'' while making the 
decision in the Federal Register notice (72 FR 536, January 5, 2007).
    Response: NMFS disagree. The analysis provided in the Federal 
Register notice (72 FR 536, January 5, 2007) clearly described in 
detail the numbers of Cook Inlet beluga whales, Pacific harbor seals, 
and harbor porpoises that may be potentially taken by Level B 
harassment as a result of the seismic operations in upper Cook Inlet. 
Although no take number was estimated for Steller sea lions and killer 
whales within the project area due to their rare presence based on 
surveys conducted in recent years, NMFS believes that the harassment of 
these species would be much less likely than those of beluga whales and 
harbor seals. NMFS believes that the numbers for all affected species 
are small.
    NMFS conducts 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 and in the EA. 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 finds that 
this action would result in no more than a negligible impact on these 
marine mammal species and/or stocks. NMFS also finds 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 (72 FR 536, January 5, 2007) and the EA 
for a detailed description of the analysis.
    Comment 4: CBD questions whether NMFS used the ``best available 
science'' in making its negligible impact statement. As CBD points out 
that in making its determination, NMFS must give the benefit of the 
doubt to the species rather than for the benefit of commercial 
exploitation.
    Response: NMFS disagree. 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 small 
numbers of marine mammals by U.S. citizens who engage in a specified 
activity (other than commercial fishing) within a specified 
geographical region if certain findings are made and either regulations 
are issued or, if the taking is limited to harassment. An 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 
subsistence uses and that the permissible methods of taking and 
requirements pertaining to the mitigation, monitoring and reporting of 
such taking are set forth. To reach a determination whether such take 
constitute a negligible impact to the marine mammal species or 
stock(s), NMFS must use the best available scientific information.
    In reaching the determination for issuance of two IHAs for 
conducting seismic surveys in upper Cook Inlet, NMFS has consulted a 
number of scientific studies in this field and prepared an EA based on 
the most recent peer-reviewed information. Where information is 
unobtainable because of ethical concerns regarding conducting invasive 
and injurious effects on marine mammals, surrogate species or 
appropriate modeling is used in lieu of empirical information on marine 
mammals. This information are reviewed by the Commission and its 
Scientific Advisors, some of whom are experts on assessing impacts on 
marine mammals from underwater sound sources. The information contained 
in the EA has also been reviewed by endangered species biologists at 
NMFS Anchorage Field Office and expert in bioacoustics at NMFS Office 
of Protected Resources. Please refer to the Federal Register notice (72 
FR 536, January 5, 2007) and the EA for a detailed description of NMFS 
analyses.
    As NMFS has used the best science currently available in making its 
negligible impact determination and because NMFS always gives the 
benefit of the doubt to the species when making these determinations, 
NMFS believes that no harm will occur to these affected species and/or 
stocks.
    Comment 5: The WDCS recommends that the IHA should not be issued 
and that seismic surveying should not be allowed to take place in the 
Cook Inlet. The WDCS further states that recent status review and 
extinction assessment reveals that Cook Inlet beluga whale population 
has not shown appreciable recovery since 1999, and should be listed 
under the Endangered Species Act (ESA) as an endangered species. The 
WDCS states that any added pressure to this population might push it 
beyond recovery.
    Response: NMFS disagrees. As stated here and in the EA, NMFS 
determined that the proposed short-term action that has several 
mitigation measures incorporated to reduce impacts to the lowest level 
practicable would result in no more than a negligible impact on Cook 
Inlet beluga whales (72 FR 536, January 5, 2007). The Cook Inlet beluga 
whale listing action under the ESA is a separate action, that is 
currently under NMFS review and consideration.
    Comment 6: CBD states that it does not believe NMFS can lawfully 
authorize any Level A harassment of Cook Inlet beluga whales.
    Response: As stated in the Federal Register notice (72 FR 536, 
January 5, 2007), no take by Level A harassment (injury) or death is 
anticipated or authorized for the proposed Cook Inlet seismic 
operations.
    Comment 7: CBD states that in light of the impending listing of the 
Cook Inlet beluga, NMFS should delay issuing any take authorization for 
the species until the ESA process is complete.
    Response: NMFS cannot legally delay issuing a take authorization 
based on the impending listing of a species. Section 101(a)(5)(D) of 
MMPA establishes a 45-day time limit for NMFS review of an IHA 
application followed by a 30-day public notice and comment period on 
any proposed authorizations for the incidental harassment of small 
numbers of marine mammals. Within 45 days of the close of the comment 
period, NMFS must either issue or deny issuance of the authorization. 
An authorization shall be granted if NMFS finds, that as here, the 
taking will have a no more than 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 subsistence uses and that 
the permissible methods of taking and requirements pertaining to the 
mitigation, monitoring and reporting of such taking are set forth, such 
as the case of this action.

NEPA Concerns

    Comment 8: The Commission is concerned about the potential impact 
of the proposed activities in conjunction with other factors that might 
be adversely affecting beluga whales (i.e.,

[[Page 17121]]

cumulative effects). The Commission states that such factors include 
increased vessel traffic, contaminants, military operations, waste 
management, urban runoff, and furthermore, a variety of new activities 
that are planned for Cook Inlet during the period for which the 
incidental taking authorizations are sought.
    Response: NMFS concurs with the Commission's concern regarding the 
potential impact of the proposed activities in conjunction with other 
factors that might be adversely affecting the Cook Inlet beluga whale 
stock. NMFS also believes that extra caution is needed when proceed in 
authorizing any IHAs for Cook Inlet beluga whales, due to the 
precarious situation of this stock. Therefore, NMFS has conducted a 
detailed analysis on the cumulative impact on the environment which may 
result from the incremental impact of the proposed short-term seismic 
survey action when added to other past, present, and reasonably 
foreseeable future actions within upper Cook Inlet. The analyses are 
described in detail in the Environmental Assessment on the Issuance of 
Incidental Harassment Authorizations to ConocoPhillips Alaska, Inc. and 
Union Oil Company of California to Take Marine Mammals by Harassment 
Incidental to Conducting Seismic Operations in Northwestern Cook Inlet, 
Alaska.
    Comment 9: CBD states that for the analyses on CPAI and UOCC's 
applications, NMFS must consider these effects together with all other 
activities that affect these species, stocks, and local populations, 
other anthropogenic risk factors such as other industrial development, 
climate change, and the cumulative effect of these activities over 
time.
    Response: NMFS has conducted extensive analyses on the cumulative 
impact to marine mammal species within the proposed action areas in the 
EA. Please also refer to Response to Comment 8.
    Comment 10: CBD states that NMFS cannot rationally adopt its EA and 
make a Finding of No Significant Impact (FONSI). CBD states that NMFS 
must prepare a full environmental impact statement (EIS) analyzing the 
effects of the proposed seismic surveys in the context of the 
cumulative effects of all other natural and anthropogenic impacts on 
the marine mammals, habitats and communities of Cook Inlet.
    Response: In December, 2006, NMFS prepared a draft EA for public 
comment and review. During the 30-day comment period, rigorous reviews 
were conducted by NMFS scientists in the NMFS Alaska Office and by 
members of the Committee of Scientific Advisors on Marine Mammals of 
the Commission. In view of the information presented in this document 
and the analysis contained in the supporting draft EA prepared for this 
proposed action, and the best available scientific information on 
effects of sound on marine mammals, we have determined that the this 
action would not significantly impact the quality of the human 
environment.
    In addition, monitoring and mitigation measures described in this 
document and in the supporting draft EA when implemented will reduce 
impacts on marine mammal stock to the lowest level practicable. 
Furthermore, additional aerial monitoring measure for Cook Inlet beluga 
whales is added to the requirements for seismic operations by CPAI near 
Beluga River (see Monitoring Section below), which was included in the 
Final EA. This additional aerial monitoring measure is contained in the 
IHA issued to CPAI. In addition, all beneficial and adverse impacts of 
the proposed action have been addressed to reach the conclusion of no 
significant impacts. Accordingly, preparation of an EIS for this action 
is not warranted. Subsequently, NMFS finalized the draft EA and issued 
a FONSI on the proposed project.
    Levels and Numbers of Marine Mammals Affected
    Comment 11: CBD and one private citizen express their concerns that 
there is a threat of serious injury and mortality to the Cook Inlet 
beluga whales and other marine mammals from the proposed seismic 
surveys.
    Response: As described in detail in a Federal Register notice (72 
FR 536) published on January 5, 2007, and in the draft EA for the 
proposed action, NMFS has performed a thorough analysis on the levels 
of potential impacts to Cook Inlet beluga whales and four other species 
of marine mammals as a result of seismic operations in the upper Cook 
Inlet. Based on this analysis, which is supported by the best available 
scientific information, NMFS has come to the conclusion that only a few 
beluga whales, Pacific harbor seals, harbor porpoises, Steller sea 
lions, and killer whales may be taken incidental to seismic surveys, by 
no more than Level B harassment and that such taking will result in no 
more than a negligible impact on such species or stocks.
    Therefore, NMFS believes that the authorized harassment takes 
should be at the lowest level practicable due to incorporation of 
mitigation measures described in the IHA, the EA, and in this document.
    No take by Level A harassment (injury) or death is anticipated or 
authorized, and harassment takes should be at the lowest level 
practicable due to incorporation of strict monitoring and mitigation 
requirements conditioned in the IHA. Please refer to the Federal 
Register notice (72 FR 536, January 5, 2007) and the EA for a detailed 
description of the analysis.
    Comment 12: The Commission states that the estimated taking of up 
to 57 beluga whales incidental to the two proposed projects can be 
characterized as a small number of animals for purposes of making the 
finding required under the MMPA. However, it represents more than one-
quarter of the IUCN's estimate of the number of mature animals in this 
population (Lowry et al., 2006). Arguably, the Commission states that 
this level of anticipated taking could have more than a negligible 
impact on the survival and recovery of the stock. The Commission 
believes that caution is warranted.
    Response: NMFS agrees with the Commission that extra caution is 
needed when authorizing any incidental take permits of Cook Inlet 
beluga whales, due to the precarious situation of this stock. The IUCN 
stated that the population of Cook Inlet beluga whale is estimated at 
207 mature individuals (Lowry et al., 2006), however, there is no 
mention of any population surveys the IUCN conducted to reach this 
number. A Bayesian inference on the population size of Cook Inlet 
beluga (1994 2005) provided by the IUCN on its website (https://
www.iucnredlist.org/search/details/61442.pdf) showed that the 
population estimate of Cook Inlet beluga whales to be over 300 (range: 
approximately 290 400) whales, above NMFS' estimate of 278 whales, in 
2005. In addition, the estimated potential take of up to 57 Cook Inlet 
beluga whales would include all individuals, and the potential take 
would be limited to only Level B behavioral harassment. Furthermore, 
with the implementation of monitoring and mitigation measures discussed 
in the EA and this document, NMFS believe the actual take by harassment 
would be much lower. Therefore, NMFS does not believe that the 
anticipated taking resulted from the proposed activities would have 
more than a negligible impact on the survival and recover of the Cook 
Inlet beluga whale stock.
    Comment 13: CBD is concerned that beluga's foraging behavior and 
the large tidal fluctuations in Cook Inlet pose high risk of stranding 
at low tide even in the absence of anthropogenic disturbance.
    Response: Beluga whale stranding events in upper Cook Inlet are not 
uncommon. NMFS has reported 804

[[Page 17122]]

strandings (both individual and mass strandings) in upper Cook Inlet 
since 1988 (Vos and Shelden, 2005). Mass stranding events primarily 
occurred along Turnagain Arm, and often coincided with extreme tidal 
fluctuations (``spring tides'') and/or killer whale sighting reports 
(Shelden et al., 2003). These mass stranding events involve both adult 
and juvenile beluga whales are are apparently healthy, robust animals.
    It is uncertain why beluga whales strand in Cook Inlet. Beluga 
whales are known to intentionally strand themselves during molting, 
while rubbing their skin against rocky bottoms (NMFS, 2005). Beluga 
whales may also strand purposely or accidentally to avoid predation by 
killer whales. Stranded whales, particularly large adults, are at risk 
of mortality due to stress, hyperthermia and suffocation. During two 
mass stranding events in 1996 and 1999 involving about 120 whales, 9 
adult whales died (Moore et al., 2000). In 2003, 115 beluga whales 
stranded during five events. Five mortalities occurred during one of 
these events when 46 animals stranded in Turnagain Arm (Vos and 
Shelden, 2005). However, NMFS has determined that implementation of 
mitigation measures described in this document, such as altering vessel 
direction, power-down or shut-down of airguns when whales are detected 
to be heading towards the safety zone, carrying out ramp-up procedure 
when startup airguns, and conducting seismic surveys only during slack 
tide periods, would prevent such stranding events from occurring.
    Comment 14: HSUS states that the information provided and the 
impact analysis for Cook Inlet belugas are not based on the most recent 
sources. HSUS states that the most recent status review issued by NMFS 
for Cook Inlet beluga (Hobbs et al., 2006) updates, and dramatically 
expands on, information from the stock assessment. HSUS states that 
only the most recent information should be used when considering the 
status, distribution and effects on the stock.
    Response: NMFS agrees with the HSUS that the most recent 
information should be used when considering the status, distribution, 
and effects of the stock. NMFS has updated the EA for this action with 
new stock assessment data based on the most recent aerial surveys 
conducted by NMFS National Marine Mammal Laboratory in the 2006 season. 
The revised data updates the Cook Inlet beluga whale population at 302 
whales (NMFS, unpublished data) from the previous 278 whales assessed 
in 2005. However, NMFS does not agree with the HSUS that the Status 
Review updates, and dramatically expands on, information from the stock 
assessment. As stated in its Executive Summary, the Status Review 
``provides a summary of the best available science to aid NMFS policy 
makers'' in determining that the listing action may be warranted, and 
therefore is consistent with NMFS Draft Conservation Plan for the Cook 
Inlet Beluga Whale (Delphinapterus leucas) (draft Conservation Plan, 
NMFS, 2005a).
    Comment 15: HSUS, citing Hobbs, states that the range of beluga 
whales has contracted considerably to focus during spring and summer 
around river mouths in upper Cook Inlet, in the general area where the 
seismic projects are proposed. HSUS states that the contracted smaller 
ranges are very important habitat to a vulnerable population. HSUS is 
concerned that the mitigation measures of ramping would displace beluga 
whales and force them to utilize suboptimal habitat.
    Response: In the Status Review (Hobbs et al., 2006) the statement 
regarding the diminishing of the beluga whale's ranges provides the 
following description:
    ``In the 1970s and 1980s, beluga sightings occurred across much of 
the northern and central parts of Cook Inlet (Calkins 1984), but in the 
1990s the summer distribution diminished to only the northernmost 
portion of Cook Inlet (Rugh et al., 2000).''
    The Status Review and the draft Conservation Plan, as supported by 
NMFS long-term beluga whale surveys in Cook Inlet, showed that whales 
do not just congregate around any river mouth in upper Cook Inlet. The 
Status Review states that from late spring and throughout the summer 
months, the majority of beluga probably feed on fish species that are 
abundant in the Susitna River system and adjacent intertidal mudflats. 
The proposed project area for CPAI, as described in detail in the 
Federal Register notice (72 FR 536, January 5, 2007), is paralleling 
the shoreline from just offshore of the Beluga River south for about 6 
km, which is about 15 miles south of Susitna River mouth. This area is 
in the extreme southern edge of the area classified by NMFS as Type 2 
habitat (high value, summer feeding area) in its draft Conservation 
Plan. Since the proposed CPAI seismic operations will be completed by 
May 15, NMFS does not believe that this project would have significant 
impact to beluga foraging activities. However to ensure that CPAI 
survey does not have a significant impact, NMFS is requiring CPAI to 
conduct an aerial monitoring program (see Monitoring Section). As for 
the proposed UOCC seismic project, which would occur further south in a 
latter period (from May 15 June 15) when the majority of Cook Inlet 
belugas will be feeding around the Susitna River, Knik Arm, and 
Tumagain Arm areas (Rugh et al., 2000), no aerial monitoring is 
required. Therefore, it is not likely that the proposed seismic 
operations and the mitigation measures will displace beluga whales from 
their prime feeding ground or force them to utilize suboptimal habitat. 
Please refer to the draft Conservation Plan and the EA for a detailed 
description of beluga whales' temporal and spatial distribution in Cook 
Inlet.
    Comment 16: HSUS is concerned that displacing animals for up to 8 
hours each day (1 2 hours during each of 3 4 daily slack tides) for a 
period of months could have significant effects on foraging success and 
thus fitness of individuals in this declining population. HSUS notes 
that disturbance resulting in displacement by beluga whales does not 
appear to have been considered in the draft EA. HSUS also states that 
displacement even from a small area, if that area is important habitat, 
could have serious long term impacts on Cook Inlet beluga. In addition, 
citing Morton and Symonds (2002), HSUS states that killer whales and 
harbor porpoises have been displaced from important habitat by seal 
scrammers, a sound source similar to airguns.
    Response: NMFS disagree. Regarding the potential concern of 
displacing animals for up to 8 hours each day for the three-month 
period, since the survey vessel will be moving as it is conducting 
seismic surveys, NMFS does not believe that the whales will be 
displaced from a particular location during the entire period. The most 
likely scenario is that as the survey vessel conducts the surveys, 
marine mammals including beluga whales will be temporarily displaced 
from an approximately 370 m (1,214 ft) radius zone of influence (ZOI). 
As the vessel moves around, the ZOI will be shifting constantly. 
Therefore, no animal is expected to be displaced from an area for 
longer than 1 2 hours. NMFS considers temporary (rather than long-term) 
displacement of marine mammals as a form of behavior avoidance and is 
discussed in the draft EA (page 28). Please refer to the EA, Cook Inlet 
Beluga Conservation Plan, and Response to Comment 15 for additional 
information on beluga whale habitat.
    Regarding Morton and Symonds's (2002), HSUS incorrectly stated that 
acoustic harassment devices (AHDs) and

[[Page 17123]]

airguns were similar in acoustic features. The sound produced by an AHD 
is intermittent but is considered non-pulse, based on differences in 
measurements between continuous and impulses sound level meters 
(Harris, 1998). In addition, the 10-kHz Airmar AHD mentioned in Morton 
and Symond's (2002) was designed specifically to cause physical pain to 
seals, and the nature of killer-whale hearing (similar to most 
odontocetes including belugas) makes this species vulnerable to impact 
by this type of sound source as well. As a result, NMFS believes that 
the AHD which was used from 1993 to 1999, is not be comparable to 
seismic airguns as proposed to be used during the three-month long 
seismic surveys proposed in Cook Inlet.
    Comment 17: Citing NMFS Stock Assessment Reports (SARs), HSUS 
points out that the Gulf of Alaska harbor seals should not be treated 
as a single stock.
    Response: Whether the Gulf of Alaska harbor seals should be 
reclassified into more finely scaled stocks remains under study. Until 
NMFS officially has adopted the revised stock reclassification based on 
available scientific information, NMFS will continue to use the 
existing stock information with the latest population abundance 
assessment for management purposes under the MMPA. In addition, even if 
the Cook Inlet harbor seals were to be reclassified as a separate 
stock, NMFS does not believe that the proposed seismic project would 
have significant impact to these animals due to the rare occurrence of 
the harbor seals within the project area. The most recent count for 
harbor seals within Cook Inlet is 7,330 seals (Josh London, National 
Marine Mammal Laboratory. Pers. Comm. February 2007). NMFS calculated 
that up to 30 Pacific harbor could be taken by Level B behavioral 
harassment as a result of the seismic projects. Therefore, the 
estimated take as a result of the proposed projects would represent 0.4 
percent of the total seals in Cook Inlet.
    Comment 18: HSUS points out that the Gulf of Alaska harbor porpoise 
stock was recently revised from ``not strategic'' to ``strategic'' due 
to poor and/or outdated abundance estimates.
    Response: NMFS updated the information on Gulf of Alaska stock of 
harbor porpoise in the EA, based on the newly released draft Stock 
Assessment Report. The classification of the Gulf of Alaska harbor 
porpoises to a strategic stock is largely due to lack of information on 
incidental harbor porpoise mortality in commercial fisheries. The 
population estimate for this stock has been revised from 30,506 to 
41,854 porpoises. Therefore, the percentage of estimated take of the 
Gulf of Alaska harbor porpoise by seismic surveys has been revised from 
0.02 percent to 0.01 percent.
    Comment 19: HSUS is concerned that information on harbor porpoise 
densities in Cook Inlet was based on surveys done in 1991 1993, 
therefore, the abundance data would not be accurate. HSUS further 
states that harbor porpoises are not evenly distributed but ``tend to 
clump in areas where forage conditions are more ideal, making them more 
vulnerable to anthropogenic impacts in some areas than others.'' Citing 
Rugh (2005), HSUS states that there were high densities of harbor 
porpoises in two different areas in Cook Inlet.
    Response: NMFS acknowledges that the survey studies on population 
densities of Cook Inlet harbor porpoises cited (Dalheim et al., 2002) 
were conducted 14 years ago, however, there is no evidence that these 
data are not accurate. A reference search did not show that there are 
any better or more recent studies available. Therefore, NMFS considers 
that Dalheim et al.'s (2002) research on population densities of Cook 
Inlet harbor porpoises is the best scientific information available 
thus far.
    The statement ``that harbor porpoises tend to clump in areas where 
forage conditions are more ideal, making them more vulnerable to 
anthropogenic impacts in some areas than others'' is not totally 
relevant since the proposed seismic surveys do not necessarily seek 
areas where forage conditions are good for marine mammals. Even if the 
areas were the same, marine mammals clustered in groups would offer a 
better opportunity to see them and implement appropriate mitigation.
    NMFS assumes that the citation HSUS mentioned is Rugh et al. 
(2005), NOAA Technical Memorandum NMFS-AFSC-149: Aerial Surveys of 
Belugas in Cook Inlet, Alaska, June 2001, 2002, 2003, and 2004. In this 
paper, Rugh et al. stated that twice they located high density areas 
for harbor porpoises: south of Tuxedni Bay in 1994 and south of 
Chinitna Bay in 2004. Both areas are located in lower Cook Inlet, which 
are not the proposed project area. This statement supports NMFS 
assessment in its EA that harbor porpoises tend to concentrate in lower 
Cook Inlet.
    Comment 20: Citing NMFS' draft EA that there is no abundance 
estimate of Steller sea lions and killer whales in the proposed project 
area, HSUS and the AWI state that this does not preclude the occurrence 
of Steller sea lion within the project area and the analysis in the EA 
is inadequate. HSUS further questions NMFS regarding source references 
that Steller sea lions seldom occur in upper Cook Inlet besides data 
from aerial surveys conducted in June and July.
    Response: First, one should not interpret the statement in the 
draft EA that no population estimate has been made for Steller sea 
lions and killer whales within the proposed project area as that NMFS 
has no knowledge whether these species occur in the area or not. 
Repeated aerial surveys by NMFS for Cook Inlet beluga whales have 
recorded any sighting of other marine mammals including Steller sea 
lions and killer whales, however, no efforts were made to calculate the 
abundance of these species due to their rare occurrence in the project 
area (Rugh et al., 2005). In fact, Rugh et al. (2005) documented every 
sighting of marine mammals in their beluga whale aerial survey report. 
Although systematic surveys for beluga whales are usually conducted in 
June and July, field observations were made by biologists in NMFS 
Anchorage Office throughout the year on marine mammals within Cook 
Inlet. All these observations point out that Steller sea lions are rare 
in upper Cook Inlet (Brad Smith, NMFS Anchorage Office. Pers. Comm. 
February 2007).

Acoustic Impacts

    Comment 21: CBD, the AWI and the WDCS question NMFS assumption that 
belugas would not be harassed by seismic sounds below 160 dB re: 1 
microPa. CBD states that there are numerous studies showing significant 
behavioral impacts from received sounds well below 160 dB. For example, 
in its recent decision document related to seismic surveys associated 
with oil and gas exploration in the Chukchi Sea, NMFS imposed a 120-dB 
safety zone for aggregations of bowhead whales based on its finding 
that ``bowhead whales apparently show some avoidance in areas of 
seismic sounds at levels lower than 120 dB'' (MMS, 2006). Also harbor 
porpoises have been reported to avoid a broad range of sounds low-
frequency (airgun pulses), mid-frequency (sonar transmissions), and 
high-frequency (acoustic harassment devices) at very low sound pressure 
levels (between 100 and 140 dB re: 1 microPa) (Kastelein et al., 2000; 
Olesiuk et al., 2002; Calambokidis et al., 1998; NMFS, 2005b). AWI 
states that whales have stranded and died after being exposed to lower 
levels of sound, notably in the Bahamas incident of 2001.

[[Page 17124]]

    Response: NMFS does not agree. As stated in the Federal Register 
(72 FR 536, January 5, 2007) and the EA, one of the most important 
aspects to assess the effects of high intensity sounds on marine 
mammals is to understand their hearing sensitivity. For most small- and 
medium-sized odontocetes (beluga whales included), the most sensitive 
hearing ranges fall between 1 and 100 kHz (Richardson et al., 1995). 
Although it has been reported that beluga whale's hearing extends to as 
low as 40 75 Hz (Awbrey et al., 1988; Johnson et al., 1989), its 
hearing threshold is at about 130 140 dB re: 1 microPa (Richardson et 
al., 1995). The dominant frequencies (i.e., frequencies with highest 
sound pressure levels) of the airguns to be used in the proposed 
seismic operations are in the extreme low end of the spectrum (around 
20 Hz). NMFS believes that at these low frequency ranges, the ability 
for belugas to detect sound is greatly reduced, therefore, belugas are 
not likely to be harassed.
    While bowhead whales may be affected by seismic sounds above 120 dB 
re: 1 microPa, they are mostly found within the Arctic, do not occur in 
Cook Inlet and therefore will not be affected. Other mysticete species 
are not expected in upper Cook Inlet. The harbor porpoise examples 
given in the comments were exposed to acoustic signals with much higher 
frequencies than the acoustic signals being produced by the proposed 
project (150 3,500 Hz). For example, the experiment conducted by 
Kastelein et al. (2000) used three types of sounds, all had harmonics 
with high sound pressure levels above the range of 11 to 30 kHz. Gordon 
et al. (1998) reported on experimental playbacks to harbor porpoises in 
inshore waters around Orkney, United Kingdom using a small source air 
gun (source level 228 dB re: 1 microPa zero-to-peak at 1 m) and 
observed no changes in the rate of acoustic detection as a result of 
sound exposure. In general, it is well known that harbor porpoises' 
hearing sensitivity drops sharply as frequency goes under 8,000 Hz 
(Andersen, 1970; Kastelein et al., 2002).
    In addition, it is also important to understand that whether a 
marine mammal would be harassed by sound or not also depends on the 
context of the animal's behavior and the acoustical property of the 
sound signal. It is also very possible that whales may not be harassed 
when exposed to sound at received levels higher than 160 dB re: 1 
microPa (e.g., Madsen and Mohl, 2000; Harris et al., 2001). 
Furthermore, as discussed in the EA, the upper Cook Inlet is one of the 
most industrialized and urbanized regions of Alaska. As such, ambient 
noise levels are high and range from 100 120 dB re: 1 microPa 
(Blackwell and Greene, Jr., 2002). Therefore, it is likely that marine 
mammals in this region are habituated to these anthropogenic sounds.
    NMFS does not concur with the AWI that there was a whale stranding 
event in the Bahamas in 2001 caused by exposure to sound levels under 
160 dB re: 1 microPa, as mentioned in its comment (no reference 
provided). There was a mass stranding event in the Bahamas on March 15 
16, 2000, which is possibly linked to naval exercises in the area (Cox 
et al., 2006). Although no received levels and mechanism that caused 
the stranding were determined, it was revealed that four of five ships 
were using mid-frequency sonar (AN/SQS-53C: 2.6 3.3 kHz, approximately 
235 dB re: 1 microPa SPL, AN/SQS-56: 6.8, 7.5, and 8.2 kHz, 
approximately 223 dB re: 1 microPa SPL; Anon, 2001). These sounds are 
very different from the seismic pulses in terms of frequencies, 
amplitudes, and temporal patterns.
    Comment 22: Citing a recently issued IHA by NMFS to the National 
Science Foundation for conducting seismic surveys, CBD is concerned 
that beluga whales could be displaced at a significant distance (up to 
20 km, or 12.4 mi) from a sound source.
    Response: NMFS notes that there have been observations that small 
toothed whales sometimes move away, or maintain a somewhat greater 
distance from the seismic vessel, when a large array of airguns is 
operating than when it is silent (e.g., Calambokidis and Osmek, 1998; 
Stone, 2003). Aerial surveys during seismic operations in the 
southeastern Beaufort Sea recorded much lower sighting rates of beluga 
whales within 10 20 km (16 - 32 mi) of an active seismic vessel. These 
results were consistent with the low number of beluga sightings 
reported by observers aboard the seismic vessel, suggesting that some 
belugas might be avoiding the seismic operations at distances of 10-20 
km (Miller et al., 2005). However, as noted in the Federal Register 
notice referenced by the CBD (71 FR 43450, August 1, 2006), NMFS does 
not consider minor movements away from an acoustic source to rise to 
Level B harassment, since at the range of 7,097 and 10,646 m (4.4-6.6 
mi; depending on ocean depths), received levels dropped down to below 
160 dB re: 1 microPa.
    Comment 23: The WDCS states the possibility that up to 57 Cook 
Inlet beluga whales (up to 20 percent of the population) could be 
subjected to 180-dB received level is unacceptable. Given the most 
recent research survey, providing a population abundance estimate of 
only 278 animals, it would be unacceptable for even one animal to be 
subjected to the received levels proposed during the seismic surveys.
    Response: NMFS does not think the WDCS statement is accurate. Based 
on NMFS' calculation, as discussed in the draft EA, no Cook Inlet 
beluga whales would be subjected to noise levels equal to or greater 
than 180 dB re: 1 microPa (rms) from the proposed seismic surveys. 
Based on NMFS' acoustic criteria, 180 dB re: 1 microPa (rms) is 
considered to be the onset of TTS and exposure of cetaceans to this 
level of noise will not be permitted under these IHAs. Strict 
mitigation and monitoring measures described in the EA and required 
under these IHAs will prevent any cetaceans from exposure to 180 dB re: 
1 microPa (rms) or greater.
    NMFS states that up to 57 beluga whales (representing 19 percent of 
the population based on the most recent survey data) could be exposed 
to noise levels of 160 dB re: 1 microPa (rms), which is the onset of 
Level B behavioral harassment, as a result of the seismic operations.
    Comment 24: CBD questions NMFS' Level A harassment criteria of 180 
dB re: 1 microPa for cetacean and 190 dB re: 1 microPa for pinniped 
species. CBD cites that in 2002, 2 Cuvier's beaked whales (Ziphius 
cavirostris) were found to have stranded in the Gulf of California, 
Mexico, coincident with geophysical surveys that were being conducted 
in the area (Hildebrand, 2004), and in the same year, humpback whales 
(Megaptera novaeangliae) were reported to have stranded in unusually 
high numbers along Brazil's Abrolhos Banks, where oil-and-gas surveys 
were being conducted (Engel et al., 2004). In addition, CBD states that 
the western Pacific gray whales were displaced from feeding grounds and 
exhibited behavioral changes in response to seismic surveys off 
Russia's Sakhalin Island (Wursig et al., 1999). CBD also states that no 
studies undertaken on the acoustic sensitivity of pinnipeds suggests 
these species are at lower risk of threshold shift or auditory injury 
than cetaceans (Kastak et al., 1999; 2005), and that harbor seals have 
exhibited low discomfort thresholds to anthropogenic noise (Kastelein 
et al., 2006).
    Response: In 1998, scientists convened at the High Energy Seismic 
Sound (HESS) Workshop, reviewed the available scientific information, 
and agreed on the received sound levels above which marine mammals 
might incur permanent tissue damage resulting in a permanent threshold 
shift (PTS) of hearing. Shortly thereafter, a

[[Page 17125]]

NMFS panel of bioacousticians used the information gathered at the HESS 
workshop to establish the current Level A Harassment acoustic criteria 
for non-explosive sounds, 180 dB re: 1 microPa-m (rms) for cetaceans, 
and 190 dB re: 1 microPa-m (rms) for pinnipeds, exposed to impulsive 
sounds. In the absence of good sound scientific information for 
specific species, NMFS conservatively adopt these criteria to establish 
safety zones, within which monitoring or mitigation measures must be 
applied, for all cetacean and pinniped species.
    A study by Finneran et al. (2002) on bottlenose dolphin (Tursiops 
truncatus) and beluga whale using a behavioral response paradigm and 
exposing them to intense impulses from a seismic watergun showed that 
masking temporary threshold shifts (MTTS) occurred after being exposed 
to an impulsive sound of 160 kPa, or 226 dB re: 1 microPa p-p, with 
total energy fluxes of 186 dB re: 1 microPa2-s for the beluga whale. No 
MTTS was observed in the dolphin at the highest exposure conditions: 
207 kPa, 228 dB re: 1 microPa p-p, and 188 dB re: 1 microPa2-s total 
energy flux.
    As for these two stranding examples cited in the comment 
(Hildebrand, 2004; Engel et al., 2004) that occurred in the vicinity 
where there had been seismic surveys conducted using powerful airguns, 
a causation relationship between seismic surveys and strandings has yet 
to be scientifically established. These references did not state that 
seismic surveys are the cause of the strandings. Please see NMFS more 
detailed response to these two events in the previous notice (69 FR 
74906, December 16, 2004). NMFS notes that no measurements were made on 
the distance between the acoustic source and the marine mammals. The 
report by Wursig et al. (1999), which is also cited in the comment, 
provided a detailed study of behavioral ecology of western Pacific gray 
whale summering off Sakhalin Island. The report did not suggest that 
the species were displaced from important feeding ground. On the 
contrary, a follow up final report (Wursig et al., 2000) on the same 
subject stated that ``whales did not appear to be displaced by 
industrial activity.''
    No comparable studies have been conducted on pinnipeds regarding 
their responses to impulsive sounds. The two references (Kastak et al., 
1999; 2005) cited in the comment cannot be used to address the noise 
responses of pinnipeds for the proposed project because animals in 
these studies were exposed to octave-band noises for extended durations 
(20 22 minutes in Kastka et al., 1999; 20, 25, and 50 minutes in Kastka 
et al., 2005). In the third reference (Kastelein et al., 2006) cited in 
the comment, harbor seals were also exposed to octave-band noise, 
nonetheless, no TTS was observed. All these studies underscore the 
importance of including sound exposure metrics (incorporating sound 
pressure level and exposure duration) in order to fully assess the 
effects of noise on marine mammal hearing, not just looking at the 
absolute sound pressure levels.
    Comment 25: HSUS uses an example that workers in loud factories 
become habituated to noise in order to make money to feed their 
families, but that does not insulate them from the multiplicity of 
effects of stress or chronic sub-lethal conditions that may go 
undetected by external monitoring, therefore, the habituation to high 
level acoustic disturbance cannot be dismissed.
    Response: NMFS does not believe that the HSUS' example of workers 
working in noisy factories is a good analogue to marine mammals living 
in a noisy environment due to the different contexts. In addition, such 
comparison cannot be performed as HSUS did not provide quantitative 
data on the noise levels of the ``loud factories'' that are presumed to 
cause stress or chronic sub-lethal condition.
    The marine environment is an efficient medium for sound propagation 
and the ambient noise, as shown in many studies, are much higher 
underwater than in air, although quantitative comparison is often 
impossible due to different reference point in acoustic pressures 
selected. Many of the sounds (e.g., those from marine life, wind, surf, 
waves, rain, bubbles, ice, earthquakes, and thunder/lightning) 
underwater occur naturally and are considered an intrinsic property of 
the environment (Wenz, 1962; Diachok and Winokur, 1974; Arnold et al., 
1984; Wilson et al., 1984; Nystuen and Farmer, 1987; Richardson et al., 
1995; Tkalich and Chan, 2002; Ma et al., 2005). Therefore, marine 
mammal hearing sensitivities may not reflect those of terrestrial 
animals. Furthermore, the proposed seismic surveys would occur in a 
short period of three months and are not confined in one fixed spot, 
while the factory workers in HSUS' example are presumed to be working 
in the same noisy environment for a number of years.
    Comment 26: HSUS states that when describing the characteristics of 
seismic sound, NMFS did not cite the most recent literature except 
Richardson et al. (1995), Marine Mammal and Noise (Academic Press), 
which HSUS considers to be outdated. HSUS brings NMFS attention to a 
recent paper by Madsen et al. (2006) indicating that seismic airguns 
generate significant sound energy at frequencies well above those of 
interest to the surveyors. Citing Madsen et al. (2006), HSUS states 
that received levels of up to 147 dB re: 1 microPa rms were generated 
for higher frequencies, which may cause avoidance, stress, and masking 
to marine mammals.
    Response: NMFS disagrees. NMFS does not consider Richardson et 
al.'s (1995) work as outdated. To the contrary, it is still one of the 
most authoritative and widely cited literatures on characteristics of 
seismic sound and airguns. In fact, Richardson et al. (1995) has noted 
that low frequency airgun pulses contain energy in much higher 
frequencies, which was also cited in our draft EA. NMFS is aware of 
Madsen et al.'s work and considers it an important contribution to our 
understanding of seismic sounds propagation in deep water.
    In addition, NMFS does not believe that received levels from 
inpulse noise (sound as seismic) of up to 147 dB re: 1 microPa rms 
would cause a biologically significant response by marine mammal 
species and stocks in Cook Inlet (see Response to Comment 21). However, 
in recognition of the potential of horizontal propagation of sound 
energy at higher frequencies, NMFS requires that safety zones based on 
180 dB and 190 dB re: 1 microPa rms isopleths around the survey vessel 
be established for cetacean and pinniped species, respectively at the 
distance of greatest propagation. Please refer to the EA and Federal 
Register notice (72 FR 536, January 5, 2007) for detailed information.
    Comment 27: HSUS states that NMFS did not consider some of the more 
recent work examining the impacts of seismic airguns on marine mammals. 
HSUS brings NMFS attention to the proceedings from a workshop on this 
issue by the International Whaling Commission (IWC) Scientific 
Committee's Standing Working Group on Environmental Concerns. In 
addition, HSUS states that very outdated sources (primarily from the 
1990s) of empirical work on the impact of seismic airguns on marine 
mammals were cited in the draft EA.
    Responses: NMFS is aware of the proceeding by the 2006 IWC 
Scientific Committee's Standing Working Group on Environmental Concerns 
and has reviewed all its session papers on impacts of seismic surveys 
on cetaceans. These papers and the proceeding were not considered in 
the EA because none

[[Page 17126]]

of the session papers were peer-reviewed, and many are summaries of 
original studies that were already included in the EA. Nonetheless, a 
few of the new studies presented at the IWC did provide information on 
long-range effects of airgun noise on marine mammals. For example, 
field monitoring of seismic surveys by U.S. Geological Survey (USGS) in 
Juan de Fuca Strait, Georgia Strait, Puget Sound, Hood Canal, and other 
marine waters in British Columbia and Washington showed that most 
marine mammals exhibited avoidance and Level B behavioral change when 
exposed at 170 183 dB re: 1 microPa rms but were not affected when 
levels were below 170 dB, except for harbor porpoises (Bain and 
Williams, 2006). Although the authors stated that there were 
insufficient numbers of individuals of marine mammals observed to merit 
statistical analysis, the general observations support NMFS 160-dB 
criteria for the onset of Level B behavioral harassment.
    As regards to the sources used in the draft EA, NMFS does not 
considered them outdated. All references NMFS used are peer-reviewed 
and are cited in peer-reviewed papers. All these papers were tested in 
time and thus NMFS considers them to be the best available scientific 
information. A quick tally showed that among the 21 references cited on 
noise impacts on marine mammals, 3 (14 percent) were published in the 
1980s, 8 (38 percent) in the 1990s, and 10 (48 percent) in the 2000s.
    Comment 28: HSUS states that the fact that cetaceans are near 
vessels during airgun firing, even riding the bows of vessels towing 
arrays is more a reflection of the characteristics of airgun sound 
propagation than an indication that airgun pulses do not affect 
cetaceans. HSUS states that there may well be sound shadows closer to 
the vessel and the animals may be attracted to the vessels in an effort 
to escape exposure to the blast.
    Response: The Lloyd-mirror effect phenomenon, where acoustic energy 
is diminished in a sound field near the surface where engine and 
propeller noise from a ship is blocked by the vessel's hull, has been a 
discussion regarding ship strike of large whales (Terhune and Verboom, 
1999; Blue et al., 2001). However, it is highly unlikely that the 
received levels would be reduced to the degree from the source (airgun 
array) with no blockage between the source and the receivers. 
Nonetheless, the IHAs require the surveyors to shut down the airgun as 
soon as a marine mammal is sighted or believed to be inside the safety 
zones, and no airgun can be started until 30 minutes after all marine 
mammals have vacated the safety zones.
    Comment 29: HSUS states that beluga whales react to low frequency 
sounds from icebreaker ships, probably at the level at which they are 
just able to detect them, up to 40 km away (Finley et al., 1990; Cosens 
and Dueck, 1993). HSUS questions NMFS' assumption that beluga whales do 
not react to low frequency sounds.
    Response: NMFS does not agree with HSUS' extrapolation of beluga 
reactions to approaching icebreaker ship sounds to predict their 
responses to low-frequency seismic surveys. First, the acoustic 
characteristics of an icebreaker do not resemble those from a seismic 
airgun array. While seismic airguns produce transient sounds (pulses), 
the noise from a ship is continuous sounds (non-pulses) (Richardson et 
al., 1995). In addition, HSUS incorrectly classified sounds from 
icebreaker ships as ``low-frequency.'' In fact, mid-point frequencies 
of intense sound levels (over 162 dB re: 1 microPa) from icebreaker 
ships recorded ranged from 50.1 Hz 5.01 kHz (Cosens and Dueck, 1993). 
In a more recent study, the statistical source spectrum levels in 12th 
octave bands between 100 Hz and 20 kHz from the Canadian Coast Guard 
icebreaker Henry Larsen, were calculated at a median source level of 
192 dB re: 1 microPa @ 1 m from bubbler system noise and 197 dB re: 1 
microPa @ 1 m for noise associated with propeller cavitation along this 
entire frequency range (Erbe and Farmer, 2000). Therefore, their 
effects of noises from icebreaking ships and seismic airguns to marine 
mammals cannot be compared. Furthermore, the contexts of the acoustic 
signals and the prior exposure of anthropogenic sounds by the whales 
need also to be taken into consideration when interpreting animal 
responses. As suggested in both publications cited by HSUS (Finley et 
al., 1990; Cosens and Dueck, 1993), the beluga whale reactions to 
icebreaker noise at unprecedented ranges in the remote Canada High 
Arctic was probably due to the fact that these animals are relatively 
naive with respect to exposure to industrial noise. Richardson et al. 
(1995) also suggested that the acute responsiveness to icebreakers was 
probably caused by the partial confinement of whales by heavy ice, 
scarcity of ships in the high arctic in spring, and ideal sound 
propagation conditions (LGL and Greeneridge, 1986).
    Comment 30: HSUS states that there is an overemphasis on avoidance 
behavior and hearing loss when discussing the potential impacts of the 
seismic surveys on marine mammals in Cook Inlet in NMFS' draft EA. 
Citing the IWC Report of the Standing Working Group on Environmental 
Concerns (2006), HSUS states that ``Clark and his colleagues...suggest 
strongly that masking may be a significant problem for animals exposed 
to seismic airguns,'' but it was not mentioned in the draft EA.
    Response: NMFS considers that long-term displacement and hearing 
loss as a result of anthropogenic sounds are biologically significant 
impacts to marine mammals, as discussed in detail in the draft EA. 
Therefore, NMFS considers it better to overemphasize and to call extra 
attention to the reviewers and the public regarding the danger of these 
impacts, than to have these issues overlooked. However, NMFS does not 
believe beluga whale or other marine mammal acoustic communications 
would be masked as a result from the seismic surveys. For the most 
part, the low-frequency and intermittent seismic pulses, the high-
frequency communication calls of five species of marine mammals in Cook 
Inlet, and the broadband echolocation signals from three cetacean 
species do not overlap in either frequency or temporal domain. And the 
non-sequential, high-frequency nature of cetacean communication signals 
(whistles and pulsed calls) can be easily transmitted in between the 
brief seismic pulses.
    The IWC report (IWC, 2006) did not state or even suggest that 
masking is a pot