[Federal Register Volume 75, Number 156 (Friday, August 13, 2010)]
[Notices]
[Pages 49760-49811]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-19962]



[[Page 49759]]

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Part VI





Department of Commerce





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National Oceanic and Atmospheric Administration



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Takes of Marine Mammals Incidental to Specified Activities; Taking 
Marine Mammals Incidental to Open Water Marine Seismic Survey in the 
Chukchi Sea, Alaska; Notice

  Federal Register / Vol. 75 , No. 156 / Friday, August 13, 2010 / 
Notices  

[[Page 49760]]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XW13


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Open Water Marine Seismic Survey in 
the Chukchi Sea, Alaska

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

ACTION: Notice; issuance of an incidental take authorization.

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SUMMARY: In accordance with the Marine Mammal Protection Act (MMPA) 
regulations, notification is hereby given that NMFS has issued an 
Incidental Harassment Authorization (IHA) to Statoil USA E&P Inc. 
(Statoil) to take, by harassment, small numbers of 12 species of marine 
mammals incidental to a marine seismic survey program in the Chukchi 
Sea, Alaska, during the 2010 Arctic open water season.

DATES: Effective August 6, 2010, through November 30, 2010.

ADDRESSES: Inquiry for information on the incidental take authorization 
should be addressed to Michael Payne, Chief, Permits, Conservation and 
Education Division, Office of Protected Resources, National Marine 
Fisheries Service, 1315 East-West Highway, Silver Spring, MD 20910. A 
copy of the application containing a list of the references used in 
this document, NMFS' Environmental Assessment (EA) and Finding of No 
Significant Impact (FONSI), and the IHA may be obtained by writing to 
the address specified above, telephoning the contact listed below (see 
FOR FURTHER INFORMATION CONTACT), or visiting the Internet at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications.
    Documents cited in this notice may be viewed, by appointment, 
during regular business hours, at the aforementioned address.

FOR FURTHER INFORMATION CONTACT: Shane Guan, Office of Protected 
Resources, NMFS, (301) 713-2289 or Brad Smith, NMFS, Alaska Region, 
(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, a notice of a proposed authorization is 
provided to the public for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s), will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for subsistence uses (where 
relevant), and if the permissible methods of taking 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 U.S. 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

    NMFS received an application on December 24, 2009, from Statoil for 
the taking, by harassment, of marine mammals incidental to 3D and 2D 
marine seismic surveys in the Chukchi Sea, Alaska, during the 2010 
open-water season. After addressing comments from NMFS, Statoil 
modified its application and submitted a revised application on April 
12, 2010. The April 12, 2010, application was the one available for 
public comment (see ADDRESSES) and considered by NMFS for the IHA.
    The marine seismic survey will use two towed airgun arrays 
consisting of 26 active (10 spare) airguns with a maximum discharge 
volume of 3,000 cubic inch (in\3\). The 3D survey will take place in a 
915 mi\2\ (2,370 km\2\) survey area approximately 150 mi (241 km) west 
of Barrow in water depth of approximately 100 to 165 ft (30 to 50 m). 
The seismic survey is designed to collect 3D data of the deep sub-
surface in Statoil's Chukchi leases in support of future oil and gas 
development within the area of coverage. The data will help identify 
source rocks, migration pathways, and play types. In addition, a 2D tie 
line survey has been designed as a second priority program to acquire 
useful information in the region. The four stand alone 2D lines (with a 
total length of approximately 420 mi or 675 km) are designed to tie the 
details of the new high resolution 3D image to the surrounding regional 
geology to facilitate interpretation of more regional trends. The 
number of 2D km acquired will to some degree be dependent on the 2010 
season's restrictive ice coverage and the 3D data acquisition progress.
    Statoil intends to conduct these marine surveys during the 2010 
Arctic open-water season (July through November). Impacts to marine 
mammals may occur from noise produced by airgun sources used in the 
surveys.

Description of the Specified Activity

    Statoil plans to conduct geophysical data acquisition activities in 
the Chukchi Sea in the period late July through the end of November, 
2010. Data acquisition is expected to take approximately 60 days 
(including anticipated downtime), but the total period for this request 
was from July 25 through November 30 to allow for unexpected downtime 
(the IHA became effective on August 6, 2010). The project area 
encompasses approximately 915 mi\2\ (2,370 km\2\) in Statoil lease 
holdings in the Bureau of Ocean Energy Management, Regulation, and 
Enforcement's (BOEMRE) (formerly the Minerals Management Service) Outer 
Continental Shelf (OCS) Lease Sale 193 area in the northern Chukchi Sea 
(Figure 1 of the Statoil IHA application). The activities consist of 3D 
seismic data acquisition and a 2D tie line survey as a second priority 
program.
    The entire 3D program, if it can be completed, will consist of 
approximately 3,100 mi (4,990 km) of production line, not including 
line turns. A total of four 2D well tie lines with a total length of 
approximately 420 mi (675 km) are included in the survey

[[Page 49761]]

plan as a second priority program. The 3D seismic data acquisition will 
be conducted from the M/V Geo Celtic. The M/V Geo Celtic will tow two 
identical airgun arrays at approximately 20 ft (6 m) depth and at a 
distance of about 902 ft (275 m) behind the vessel. Each array is 
composed of three strings for a total of 26 active G-guns (4x60 in\3\, 
8x70 in\3\, 6x100 in\3\, 4x150 in\3\, and 4x250 in\3\) with a total 
discharge volume of 3000 in\3\. Each array also consists of 5 clusters 
of 10 inactive airguns that will be used as spares. One of the smallest 
guns in the array (60 in\3\) will be used as the mitigation gun. More 
details of the airgun array and its components are described in 
Appendix B of Statoil's IHA application. In addition to the airgun 
array, pinger systems (DigiRANGE II, or similar systems) will be used 
to position the streamer array relative to the vessel.
    The estimated source level for the full 3000 in\3\ array is 245 dB 
re 1 [mu]Pa (rms) at 1 m. The maximum distances to received levels of 
190, 180 160, and 120 dB re 1 [mu]Pa (rms) from sound source 
verification (SSV) measurements of the 3,147 in\3\ airgun array used in 
the Chukchi Sea during 2006-2008 were used to model the received levels 
at these distances, which show that the maximum distances are 700, 
2,500, 13,000, and 120,000 m, respectively. The SSV tests will provide 
received sound measurements in 10-dB increments between 120-190-dB 
isopleths. NMFS does not consider marine mammals exposed to impulse 
sounds below the 160 dB received level to be taken. The sole purpose of 
measuring to the 120 dB distance is to assess how far the sound source 
attenuates in the Arctic for the proposed seismic survey and the 
resulting information has not been factored into NMFS' MMPA decision 
for the Statoil seismic activities.
    The estimated source level of the mitigation gun (i.e., the single 
60 in\3\ airgun noted above) is 230 dB re 1 [mu]Pa (rms) at 1 m, and 
the modeled distances to received levels of 190, 180 160, and 120 dB re 
1 [mu]Pa (rms) are 75, 220, 1,800, and 50,000 m, respectively.
    The DigiRANGE II pinger system produces very short pulses, 
occurring for 10 ms, with source levels of approximately 180 dB re 1 
[mu]Pa (rms) at 1 m at 55 kHz, 188 dB re 1 [mu]Pa (rms) at 1 m at 75 
kHz, and 184 dB re 1 [mu]Pa (rms) at 1 m at 95 kHz. One pulse is 
emitted on command from the operator aboard the source vessel, which 
under normal operating conditions is once every 10 s. Most of the 
energy in the sound pulses emitted by this pinger is between 50 and 100 
kHz. The signal is omnidirectional. Using a simple spherical spreading 
modeling for sound propagation, the calculated distances to received 
levels of 180, 160, and 120 dB re 1 [mu]Pa (rms) are 2.5 m, 25 m, and 
2,512 m, respectively. These distances are well within the radii for 
airgun arrays and that of a single mitigation gun.
    The vessel will travel along pre-determined lines at a speed of 
about 4-5 knots while one of the airgun arrays discharges every 8-10 
seconds (shot interval 61.52 ft [18.75 m]). The streamer hydrophone 
array will consist of twelve streamers of up to approximately 2.2 mi (4 
km) in length, with a total of 20,000-25,000 hydrophones at 6.6 ft (2 
m) spacing. This large hydrophone streamer receiver array, designed to 
maximize efficiency and minimize the number of source points, will 
receive the reflected signals from the airgun array and transfer the 
data to an on-board processing system.
    A 2D tie line survey has been designed as a second priority program 
to allow the vessel to acquire useful information in the region. The 
four stand alone 2D lines have a total length of approximately 420 mi 
(675 km) and are designed to tie the details of the new high resolution 
3D image to known surrounding regional geology.
    The approximate boundaries of the total surface area are between 
71[deg]30' N and 72[deg]00' N and between 165[deg] W and 162[deg]30' W. 
The water depth in the survey area varies from 100 to 165 ft (30 to 50 
m).
    The vessels involved in the seismic survey activities will consist 
of at least three vessels as listed below. Specifications of these 
vessels (or equivalent vessels if availability changes) are provided in 
Appendix A of Statoil's IHA application.
     One (1) seismic source vessel, the M/V Geo Celtic or 
similar equipped vessel, to tow the two 3,000 in\3\ airgun arrays and 
hydrophone streamer for the 3D (and 2D) seismic data acquisition and to 
serve as a platform for marine mammal monitoring;
     One (1) chase/monitoring vessel, the M/V Gulf Provider or 
similar equipped vessel, for marine mammal monitoring, crew transfer, 
support and supply duties.
     One (1) chase/monitoring vessel, the M/V Thor Alpha or 
similar equipped vessel, for marine mammal monitoring, support and 
supply duties.
    The M/V Geo Celtic, or similar vessel, arrived in Dutch Harbor 
around mid July 2010. The vessels were resupplied and the crew changed 
at this port. All three vessels had departed Dutch Harbor at the end of 
July with an expected transit time of approximately 5 days (weather 
depending). Directly upon arrival in the 3D survey area, depending on 
ice conditions, the M/V Geo Celtic will deploy the airgun array and 
start operating their guns for the purpose of sound source verification 
measurements (see Statoil IHA application for more details). The 
startup date of seismic data acquisition is expected to be early/mid 
August but depends on local ice conditions.
    Upon completion of these measurements the seismic data acquisition 
in the Chukchi Sea will start and, depending on the start date, is 
expected to be completed in the first half of October. This is based on 
an estimated duration of 60 days from first to last shot point 
(including anticipated downtime). The data acquisition is a 24-hour 
operation.

Comments and Responses

    A notice of NMFS' proposal to issue an IHA to Statoil published in 
the Federal Register on June 8, 2010 (75 FR 32379). That notice 
described, in detail, Statoil's proposed activity, the marine mammal 
species that may be affected by the activity, and the anticipated 
effects on marine mammals. During the 30-day public comment period, 
NMFS received five comment letters from the following: The Marine 
Mammal Commission (Commission); the Alaska Eskimo Whaling Commission 
(AEWC); the North Slope Borough Office of the Mayor (NSB); and Alaska 
Wilderness League (AWL), Audubon Alaska, Center for Biological 
Diversity, Defenders of Wildlife, Earthjustice, Greenpeace, Natural 
Resources Defense Council, Northern Alaska Environmental Center, Ocean 
Conservancy, Oceana, Pacific Environment, Sierra Club, and World 
Wildlife Fund (collectively ``AWL''), along with an attached letter 
from Dr. David E. Bain, a contract scientist for NMFS.
    The AEWC submitted several journal articles as attachments to its 
comment letters. NMFS acknowledges receipt of these documents but does 
not intend to address the specific articles themselves in the responses 
to comments, since these articles are merely used as citations in 
AEWC's comments. AEWC also submitted copies of 2009 and 2010 Conflict 
Avoidance Agreement (CAA), since Statoil declined to sign the CAA. Dr. 
Bain also attached an in-review journal article he coauthored. Any 
comments specific to Statoil's application that address the statutory 
and regulatory requirements or findings NMFS must make to issue an IHA 
are addressed in this section of the Federal Register notice.

[[Page 49762]]

General Comments

    Comment 1: AEWC believes that NMFS should not issue incidental take 
authorizations for oil and gas-related activities given the current 
suspension of offshore drilling in Alaska and pending reorganization of 
the Minerals Management Service (MMS). AEWC points out that the harm 
caused by an oil spill is not the only risk to marine mammals posed by 
oil and gas activities on the OCS and that there are concerns regarding 
underwater noise from geophysical activities and the threats posed to 
marine mammals from noise and chemical pollution, as well as increased 
vessel traffic. AEWC further claims that many times, NMFS issued IHAs 
over the objections of the scientific and subsistence communities as 
well as the agencies' own scientists.
    Response: The legal requirements and underlying analysis for the 
issuance of an IHA concerning take associated with seismic activities 
are unrelated to the moratorium on offshore drilling and reorganization 
of the MMS. In order to issue an authorization pursuant to Section 
101(a)(5)(D) of the MMPA, NMFS must determine that the taking by 
harassment of small numbers of marine mammals will have a negligible 
impact on affected species or stocks, and will not have an unmitigable 
adverse impact on the availability of affected species or stocks for 
taking for subsistence uses. If NMFS is able to make these findings, 
the Secretary is required to issue an IHA. In the case of Statoil's 
activities for 2010 (as described in the application, the notice of 
proposed IHA (75 FR 32379; June 8, 2010) and this document), NMFS 
determined that it was able to make the required MMPA findings. 
Additionally, as described later in this section and throughout this 
document, NMFS has determined that Statoil's activities will not result 
in injury or mortality of marine mammals, and no injury or mortality is 
authorized under the IHA.
    As discussed in detail in the proposed IHA (75 FR 32379; June 18, 
2010), the EA for the issuance of IHAs to Shell and Statoil for the 
proposed open water marine and seismic surveys, and this document, NMFS 
has conducted a thorough analysis of the potential impacts of 
underwater anthropogenic sound (especially sound from geophysical 
surveys) on marine mammals. We have cited multiple studies and research 
that support NMFS MMPA and National Environmental Policy Act (NEPA) 
determinations that the localized and short-term disturbance from 
seismic surveys, with strict mitigation and monitoring measures 
implemented, are likely to result in negligible impacts to marine 
mammals and their habitat and no significant impact to the human 
environment, respectively. Although issuance of the IHA may be of 
concern to certain members of the public, the proposed issuance of the 
IHA was carefully reviewed and analyzed by NMFS scientists at 
headquarters and through Endangered Species Act (ESA) section 7 
consultation at NMFS Alaska Regional Office, and by an independent 
bioacoustics expert. Based on those reviews, NMFS staff in the Office 
of Protected Resources made appropriate changes to this document.
    Comment 2: The Commission requests that NMFS clarify whether the 3D 
and 2D seismic surveys will occur simultaneously or independent of one 
another and, if they will occur independently, recalculate the total 
exposed area and subsequent exposures for the 2D surveys.
    Response: As stated in Statoil's IHA application, the 3D and 2D 
seismic surveys will occur independently. The total exposed area and 
subsequent exposures for the 2D surveys are reported in Statoil's IHA 
application.

MMPA Concerns

    Comment 3: AEWC notes their disappointment in NMFS for releasing 
for public comment an incomplete application from Statoil that fails to 
provide the mandatory information required by the MMPA and NMFS' 
implementing regulations. AEWC requests that NMFS return Statoil's 
application as incomplete, or else the agency risks making arbitrary 
and indefensible determinations under the MMPA. The following is the 
information that AEWC believes to be missing from Statoil's 
application: (1) For several species, a thorough ``description of the 
status, distribution, and seasonal distribution (when applicable) of 
the affected species or stocks of marine mammals likely to be 
affected'' (50 CFR 216.104(a)(4)); (2) a description of the ``age, sex, 
and reproductive condition'' of the marine mammals that will be 
impacted, particularly in regard to bowhead whales (50 CFR 
216.104(a)(6)); (3) an adequate detailing of ``the anticipated impact 
of the activity upon the species or stock of marine mammals'' (50 CFR 
216.104(a)(7)); (4) the economic ``availability and feasibility * * * 
of equipment, methods, and manner of conducting such activity or other 
means of effecting the least practicable adverse impact upon the 
affected species or stocks, their habitat, and on their availability 
for subsistence uses, paying particular attention to rookeries, mating 
grounds, and areas of similar significance'' (50 CFR 216.104(a)(11)); 
and (5) suggested means of learning of, encouraging, and coordinating 
any research related activities (50 CFR 216.104(a)(14)). NSB also notes 
its concern about the lack of specificity regarding the timing and 
location of the proposed surveys, as well as the lack of specificity 
regarding the surveys themselves.
    Response: NMFS does not agree that it released an incomplete 
application for review during the public comment period. After NMFS' 
initial review of the application, NMFS submitted questions and 
comments to Statoil on its application. After receipt and review of 
Statoil's responses, which were incorporated into the final version of 
the IHA application that was released to the public for review and 
comment, NMFS made its determination of completeness and released the 
application, addenda, and the proposed IHA notice (75 FR 32379; June 8, 
2010). Regarding the three specific pieces of information believed to 
be missing by AEWC, Statoil's original application included a 
description of the pieces of information that are required pursuant to 
50 CFR 216.104(a)(12).
    Information required pursuant to 50 CFR 216.104(a)(4) and (6) 
requires that an applicant submit information on the ``status, 
distribution, and seasonal distribution (when applicable) of the 
affected species or stocks of marine mammals likely to be affected'' 
and ``age, sex, and reproductive condition (if possible)'' of the 
number of marine mammals that may be taken, respectively. In the 
application, Statoil described the species expected to be taken by 
harassment and provided estimates of how many of each species were 
expected to be taken during their activities. The status and 
distribution of these species are included in Section IV of Statoil's 
IHA application, the proposed IHA (75 FR 32379; June 8, 2010), and in 
this document. However, in most cases, it is difficult to estimate how 
many animals, especially cetaceans, of each age, sex, and reproductive 
condition will be taken or impacted by seismic surveys, because group 
composition of animals varies greatly by time and space.
    In Section VII of Statoil's IHA application, the proposed IHA (75 
FR 32379; June 8, 2010), and in this document, detailed discussion on 
the anticipated impacts from the proposed Statoil open water seismic 
survey in the Chukchi is provided, as required under 50 CFR 
216.104(a)(7). The description of the anticipated impacts includes

[[Page 49763]]

discussions on potential effects from airgun noise and pinger signers.
    Statoil also provided information on economic ``availability and 
feasibility * * * of equipment, methods, and manner of conducting such 
activity or other means of effecting the least practicable adverse 
impact upon the affected species or stocks, their habitat, and on their 
availability for subsistence uses, paying particular attention to 
rookeries, mating grounds, and areas of similar significance'' (50 CFR 
216.104(a)(11)) in its IHA application. In its application, Statoil 
states that four main mitigations regarding the open water marine 
seismic survey in the Chukchi Sea are proposed: (1) Timing and 
locations for active survey acquisition work; (2) to configure airguns 
in a manner that directs energy primarily down to the seabed thus 
decreasing the range of horizontal spreading of noise; (3) using an 
energy source which is as small as possible while still accomplishing 
the survey objectives; and (4) curtailing active survey work when the 
marine mammal observers sight visually (from shipboard) the presence of 
marine mammals within identified ensonified zones. Details of these 
mitigation measures are discussed further in the 4MP that is included 
in Statoil's IHA application. In addition to these measures, NMFS' 
Notice of Proposed IHA (75 FR 32379; June 8, 2010) described mitigation 
measures proposed to be implemented by Statoil (outlined in the 
application), as well as additional measures proposed by NMFS for 
inclusion in an IHA.
    Lastly, information required pursuant to 50 CFR 216.104(a)(14) was 
also included in Statoil's application. Statoil states that it will 
cooperate with any number of external entities, including other energy 
companies, agencies, universities, and NGOs, in its efforts to manage, 
understand, and fully communicate information about environmental 
impacts related to seismic activities. Statoil is a member of the OGP 
E&P Sound & Marine Life joint industry programme (JIP), which is an 
international consortium of oil and gas companies organized under the 
OGP in London. The objective of the JIP program is to obtain valid data 
on the effects of sounds produced by the gas exploration and production 
industry on marine life. Additionally, Statoil, Shell, and 
ConocoPhillips (CPAI) are jointly funding an extensive science program 
in the Chukchi Sea, which will be carried out by Olgoonik-Fairweather 
LLC to continue the acoustic monitoring programs of 2006-2009 with a 
total of 44 acoustic recorders distributed both broadly across the 
Chukchi lease area and nearshore environment and intensively on the 
Statoil, Burger (Shell), and Klondike (CPAI) lease holdings. Please 
refer to Statoil's IHA application and the proposed IHA (75 FR 32379; 
June 8, 2010) for a detailed description of the science program.
    In conclusion, NMFS believes that Statoil provided all of the 
necessary information to proceed with publishing a proposed IHA notice 
in the Federal Register.
    Comment 4: AEWC and NSB state that NMFS failed to issue a draft 
authorization for public review and comment. The plain language of both 
the MMPA and NMFS' implementing regulations require that NMFS provide 
the opportunity for public comment on the ``proposed incidental 
harassment authorization'' (50 CFR 216.104(b)(1)(i); 16 U.S.C. 
1371(a)(5)(D)(iii)) and not just on the application itself as NMFS has 
done here. Given Statoil's refusal to sign the CAA and without a 
complete draft authorization and accompanying findings, AEWC states 
that it cannot provide meaningful comments on Statoil's proposed 
activities, ways to mitigate the impacts of those activities on marine 
mammals, and measures that are necessary to protect subsistence uses 
and sensitive resources.
    Response: The June 8, 2010 proposed IHA notice (75 FR 32379) 
contained all of the relevant information needed by the public to 
provide comments on the proposed authorization itself. The notice 
contained the permissible methods of taking by harassment, means of 
effecting the least practicable impact on such species (i.e., 
mitigation), measures to ensure no unmitigable adverse impact on the 
availability of the species or stock for taking for subsistence use, 
requirements pertaining to the monitoring and reporting of such taking, 
including requirements for the independent peer review of the proposed 
monitoring plan. The notice provided detail on all of these points, 
and, in NMFS' view, allowed the public to comment on the proposed 
authorization and inform NMFS' final decision. Additionally, the notice 
contained NMFS' preliminary findings of negligible impact and no 
unmitigable adverse impact.
    The signing of a CAA is not a requirement to obtain an IHA. The CAA 
is a document that is negotiated between and signed by the industry 
participant, AEWC, and the Village Whaling Captains' Associations. NMFS 
has no role in the development or execution of this agreement. Although 
the contents of a CAA may inform NMFS' no unmitigable adverse impact 
determination for bowhead and beluga whales and ice seals, the signing 
of it is not a requirement. While a CAA has not been signed and a final 
version agreed to by industry participants, AEWC, and the Village 
Whaling Captains' Associations, NMFS was provided with a copy of the 
version ready for signature by AEWC. NMFS has reviewed the CAA and 
included several measures from the document which relate to marine 
mammals and avoiding conflicts with subsistence hunts in the IHA. Some 
of the conditions which have been added to the IHA include: (1) 
Avoiding concentrations of whales and reducing vessel speed when near 
whales; (2) conducting sound source verification measurements; and (3) 
participating in the Communication Centers. Despite the lack of a 
signed CAA for 2010 activities, NMFS is confident that the measures 
contained in the IHA will ensure no unmitigable adverse impact to 
subsistence users.
    Comment 5: AEWC and NSB argue that Statoil has not demonstrated 
that its proposed activities would take only ``small numbers of marine 
mammals of a species or population stock,'' resulting in no more than a 
``negligible impact'' on a species or stock. In addition, NSB argues 
that NMFS has not adequately analyzed harassment associated with 
received levels of noise below 160 dB.
    Response: NMFS believes that it provided sufficient information in 
its proposed IHA notice (75 FR 32379; June 8, 2010) to make the small 
numbers and negligible impact determinations and that the best 
scientific information available was used to make those determinations. 
While some published articles indicate that certain marine mammal 
species may avoid seismic vessels at levels below 160 dB, NMFS does not 
consider that these responses rise to the level of a take as defined in 
the MMPA. While studies, such as Miller et al. (1999), have indicated 
that some bowhead whales may have started to deflect from their 
migratory path 35 km (21.7 mi) from the seismic vessel, it should be 
pointed out that these minor course changes are during migration and, 
as described in MMS' 2006 Final Programmatic Environmental Assessment 
(PEA), have not been seen at other times of the year and during other 
activities. To show the contextual nature of this minor behavioral 
modification, recent monitoring studies of Canadian seismic operations 
indicate that feeding, non-migratory bowhead whales do not move away 
from a noise source at an SPL of 160 dB. Therefore, while bowheads may 
avoid an area of 20 km (12.4 mi) around a noise source, when that 
determination requires a

[[Page 49764]]

post-survey computer analysis to find that bowheads have made a 1 or 2 
degree course change, NMFS believes that does not rise to a level of a 
``take,'' as the change in bearing is due to animals sensing the noise 
and avoiding passing through the ensonified area during their 
migration, and should not be considered as being displaced from their 
habitat. NMFS therefore continues to estimate ``takings'' under the 
MMPA from impulse noises, such as seismic, as being at a distance of 
160 dB (re 1 [mu]Pa). As explained throughout this Federal Register 
notice, it is highly unlikely that marine mammals would be exposed to 
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).
    Regarding the small number issue raised by the AEWC and NSB, NMFS 
has developed a series of estimates for marine mammals that could be 
taken as a result of Statoil's proposed marine surveys, and the 
estimated takes from these proposed activities are all under five 
percent for any affected marine mammal species or stock (see Potential 
Number of Takes by Harassment section below).

Impacts to Marine Mammals

    Comment 6: AEWC notes that based on the density estimates, Statoil 
is predicting that an average of 2,253 and 4,234 individuals of Alaska 
ringed seals may be exposed to sound levels of 160 dB and above during 
the proposed 3D and 2D seismic surveys, respectively. AEWC and NSB 
state that these are by no means ``small numbers'' of marine mammals 
that will be subjected to impacts as a result of Statoil's operations.
    Response: NMFS determined that the small numbers requirement has 
been satisfied. Statoil has predicted that an average of 2,253 and 
4,234 individuals of Alaska ringed seals may be exposed to sound levels 
of 160 dB and above as the result of Statoil's proposed 3D and 2D 
marine seismic surveys, respectively, and NMFS assumes that animals 
exposed to received levels above 160 dB are taken. However, because of 
the tendency of marine mammals to avoid the source to some degree, and 
the fact that both the marine mammals and the source are moving through 
an area, the majority of the exposures would likely occur at levels 
closer to 160 dB (not higher levels) and the impacts would be expected 
to be relatively low-level and not of a long duration. NMFS assesses 
``small numbers'' in terms relative to the population/stock size. The 
Level B harassment take estimate of a total of 6,487 Alaska stock of 
ringed seals is a small number in relative terms, because of the nature 
of the anticipated responses and in that it represents only 2.81 
percent of the regional stock size of that species (population > 
230,000), if each ``exposure'' at 160 dB represents an individual 
ringed seal. Furthermore, as discussed below, exposure of marine 
mammals to received levels at 160 dB do not always constitute a 
``take.'' Many animals may not respond to this level in a way that is 
considered biologically significant. Therefore, even though NMFS uses 
the 160 dB received level as the onset of Level B harassment for 
regulatory purposes, this does not mean that all animals exposed to 
this level or levels above 160 dB are ``taken.'' Additionally, NMFS 
believes the percentage would be even lower if animals move out of the 
seismic area. In these circumstances, animals that are outside of the 
ensonified zone (e.g., the 160 dB isopleth) would not be expected to be 
taken by Level B harassment.
    Comment 7: AWL, NSB, and AEWC noted that NMFS has acknowledged that 
permanent threshold shift (PTS) qualifies as a serious injury. 
Therefore, if an acoustic source at its maximum level has the potential 
to cause PTS and thus lead to serious injury, it would not be 
appropriate to issue an IHA for the activity (60 FR 28381; May 31, 
1995). AEWC states that therefore an LOA is required here.
    Response: In the proposed rule to implement the process to apply 
for and obtain an IHA, NMFS stated that authorizations for harassment 
involving the ``potential to injure'' would be limited to only those 
that may involve non-serious injury (60 FR 28379; May 31, 1995). While 
the Federal Register notice cited by the commenters states that NMFS 
considered PTS to be a serious injury (60 FR 28379; May 31, 1995), our 
understanding of anthropogenic sound and the way it impacts marine 
mammals has evolved since then, and NMFS no longer considers PTS to be 
a serious injury. NMFS has defined ``serious injury'' in 50 CFR 216.3 
as ``* * * any injury that will likely result in mortality.'' There are 
no data that suggest that PTS would be likely to result in mortality, 
especially the limited degree of PTS that could hypothetically be 
incurred through exposure of marine mammals to seismic airguns at the 
level and for the duration that are likely to occur in this action.
    Further, as stated several times in this document and previous 
Federal Register notices for seismic activities, there is no empirical 
evidence that exposure to pulses of airgun sound can cause PTS in any 
marine mammal, even with large arrays of airguns (see Southall et al. 
2007). PTS is thought to occur several decibels above that inducing 
mild temporary threshold shift (TTS), the mildest form of hearing 
impairment (a non-injurious effect). NMFS concluded that cetaceans and 
pinnipeds should not be exposed to pulsed underwater noise at received 
levels exceeding, respectively, 180 and 190 dB re 1 [mu]Pa (rms). The 
established 180 and 190 dB re 1 [mu]Pa (rms) criteria are the received 
levels above which, in the view of a panel of bioacoustics specialists 
convened by NMFS before TTS measurements for marine mammals started to 
become available, one could not be certain that there would be no 
injurious effects, auditory or otherwise, to marine mammals. As 
summarized later in this document, data that are now available imply 
that TTS is unlikely to occur unless bow-riding odontocetes are exposed 
to airgun pulses much stronger than 180 dB re 1 Pa rms (Southall et al. 
2007). Additionally, NMFS has required monitoring and mitigation 
measures to negate the possibility of marine mammals being seriously 
injured as a result of Statoil's activities. In the proposed IHA, NMFS 
determined that Statoil's activities are unlikely to even result in 
TTS. Based on this determination and the explanation provided here, PTS 
is also not expected. Therefore, an IHA is appropriate.
    Comment 8: AWL, NSB, and AEWC state that NMFS has not adequately 
considered whether marine mammals may be harassed at received levels 
significantly lower than 160 dB and that NMFS did not use the best 
scientific evidence in setting the sound levels against which take was 
assessed. They state that NMFS calculated harassment from Statoil's 
proposed surveying based on the exposure of marine mammals to sounds at 
or above 160 dB and that this uniform approach to harassment does not 
take into account known reactions of marine mammals in the Arctic to 
levels of noise far below 160 dB. These comments state that bowhead, 
gray, killer, and beluga whales and harbor porpoise react to sounds 
lower than 160 dB.
    Citing several papers on killer whales and harbor porpoise, Dr. 
Bain states that major behavioral changes of these animals appear to be 
associated with received levels of around 135 dB re 1 [mu]Pa, and that 
minor behavioral changes can occur at received levels from 90-110 dB re 
1 [mu]Pa or lower. He also states that belugas have been observed to 
respond to icebreakers by swimming rapidly away at distances up to 80 
km,

[[Page 49765]]

where received levels were between 94 and 105 dB re 1 [mu]Pa. Belugas 
exhibited minor behavioral changes such as changes in vocalization, 
dive patterns, and group composition at distances up to 50 km (NRC 
2003), where received levels were likely around 120 dB.
    The AWL states that harbor porpoises have been shown to be 
particularly responsive to sound, exhibiting behavioral changes, 
including exclusion from an area, at received levels of 90-110 dB or 
lower (with received levels around 70-90 dB), depending on experience 
with the noise source and environmental context. The AWL listed a 
number of papers but did not point out the source of its statement. The 
AWL also states that multiple studies confirm the sensitivity of beluga 
whales, and that they are known to alter their migration paths in 
response to icebreaker noise at received levels as low as 80 dB, and 
that belugas have been observed to respond to icebreakers by swimming 
rapidly away at distances up to 80 km.
    AEWC also states that in conducting scoping on its national 
acoustic guidelines for marine mammals, NMFS noted that the existing 
system for determining take (i.e., the 160 dB mark) ``considers only 
the sound pressure level of an exposure but not its other attributes, 
such as duration, frequency, or repetition rate, all of which are 
critical for assessing impacts on marine Mammals'' and ``also assumes a 
consistent relationship between rms (root-mean-square) and peak 
pressure values for impulse sounds, which is known to be inaccurate 
under certain (many) conditions'' (70 FR 1871, 1873; January 11, 2005). 
Thus, NMFS itself has recognized that 160 dB (rms) is not an adequate 
measure. AEWC argues that current scientific research establishes that 
120 dB (rms) is a more appropriate measure for impacts to marine 
mammals.
    Response: The best information available to date for reactions by 
bowhead whales to noise, such as seismic, is based on the results from 
the 1998 aerial survey (as supplemented by data from earlier years) as 
reported in Miller et al. (1999). In 1998, bowhead whales below the 
water surface at a distance of 20 km (12.4 mi) from an airgun array 
received pulses of about 117-135 dB re 1 [mu]Pa rms, depending upon 
propagation. Corresponding levels at 30 km (18.6 mi) were about 107-126 
dB re 1 [mu]Pa rms. Miller et al. (1999) surmise that deflection may 
have begun about 35 km (21.7 mi) to the east of the seismic operations, 
but did not provide SPL measurements to that distance and noted that 
sound propagation has not been studied as extensively eastward in the 
alongshore direction, as it has northward, in the offshore direction. 
Therefore, while this single year of data analysis indicates that 
bowhead whales may make minor deflections in swimming direction at a 
distance of 30-35 km (18.6-21.7 mi), there is no indication that the 
SPL where deflection first begins is at 120 dB; it could be at another 
SPL lower or higher than 120 dB. Miller et al. (1999) also note that 
the received levels at 20-30 km (12.4-18.6 mi) were considerably lower 
in 1998 than have previously been shown to elicit avoidance in bowheads 
exposed to seismic pulses. However, the seismic airgun array used in 
1998 was larger than the ones used in 1996 and 1997. Therefore, NMFS 
believes that it cannot scientifically support adopting any single SPL 
value below 160 dB and apply it across the board for all species and in 
all circumstances. Second, these minor course changes occurred during 
migration and, as indicated in MMS' 2006 PEA, have not been seen at 
other times of the year and during other activities. Third, as stated 
in the past, NMFS does not believe that minor course corrections during 
a migration equate to ``take'' under the MMPA. This conclusion is based 
on controlled exposure experiments conducted on migrating gray whales 
exposed to the U.S. Navy's low frequency sonar (LFA) sources (Tyack 
2009). When the source was placed in the middle of the migratory 
corridor, the whales were observed deflecting around the source during 
their migration. However, such minor deflection is considered not to be 
biologically significant. To show the contextual nature of this minor 
behavioral modification, recent monitoring studies of Canadian seismic 
operations indicate that when, not migrating, but involved in feeding, 
bowhead whales do not move away from a noise source at an SPL of 160 
dB. Therefore, while bowheads may avoid an area of 20 km (12.4 mi) 
around a noise source, when that determination requires a post-survey 
computer analysis to find that bowheads have made a 1 or 2 degree 
course change, NMFS believes that does not rise to a level of a 
``take.'' NMFS therefore continues to estimate ``takings'' under the 
MMPA from impulse noises, such as seismic, as being at a distance of 
160 dB (re 1 [micro]Pa). 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. 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). Furthermore, the behavioral 
responses by harbor porpoises (pinger) and beluga whales (icebreaker) 
were to non-impulse noises. For non-impulse noise sources, research 
shows that in general, the threshold that induces behavioral responses 
among animals tends to be much lower. Therefore, NMFS uses 120 dB as 
the onset for behavioral harassment for non-impulse noises but 160 dB 
for impulse noises. The noises from the proposed marine seismic survey 
from airgun arrays are pulses.
    The references cited in the comment letters address different 
source characteristics (continuous sound rather than impulse sound that 
are planned for the proposed seismic survey) or species (killer whales 
and harbor porpoises) that rarely occur in the proposed Arctic action 
area. Some information about the responses of bowhead and gray whales 
to seismic survey noises has been acquired through dedicated research 
and marine mammal monitoring studies conducted during prior seismic 
surveys. Detailed descriptions regarding behavioral 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. Additionally, as Statoil does not intend to use ice-breakers 
during its operations, statements regarding beluga reactions to 
icebreaker noise are not relevant to this activity.
    Regarding the last point raised in this comment by AEWC, NMFS 
recognizes the concern. However, NMFS does not agree with AEWC's 
statement that current scientific research establishes that 120 dB 
(rms) is a more appropriate measure for impacts to marine mammals

[[Page 49766]]

for reasons noted above. Based on the information and data summarized 
in Southall et al. (2007), and on information from various studies, 
NMFS believes that the onset for behavioral harassment is largely 
context dependent, and there are many studies showing marine mammals do 
not show behavioral responses when exposed to multiple pulses at 
received levels above 160 dB re 1 [mu]Pa (e.g., Malme et al. 1983; 
Malme et al. 1984; Richardson et al. 1986; Akamatsu et al. 1993; Madsen 
and M[oslash]hl 2000; Harris et al. 2001; Miller et al. 2005). 
Therefore, although using a uniform SPL of 160-dB for the onset of 
behavioral harassment for impulse noises may not capture all of the 
nuances of different marine mammal reactions to sound, it is an 
appropriately conservative way to manage and regulate anthropogenic 
noise impacts on marine mammals. Therefore, unless and until an 
improved approach is developed and peer-reviewed, NMFS will continue to 
use the 160-dB threshold for determining the level of take of marine 
mammals by Level B harassment for impulse noise (such as from airguns).
    Comment 9: NSB and AWL note that this IHA, as currently proposed, 
is based on uncertainties that are not allowed under the MMPA. Citing 
comments made by NMFS on recent MMS Lease Sale Environmental Impact 
Statements, NSB notes that NMFS stated that without more current and 
thorough data on the marine mammals in the Chukchi Sea and their use of 
these waters, it would be difficult to make the findings required by 
the MMPA. AWL points out that NMFS specifically observed that 
activities ``occurring near productive forage areas such as the Hanna 
Shoal'' or ``along migratory corridors'' are most likely to encounter 
and impact marine mammals. AWL states that Statoil's proposed surveying 
will likely take place proximate to the Hanna Shoal, which is a feeding 
ground for gray whales and is within the pathway for migrating 
bowheads. AWL furthers states that the lack of information runs up 
against the precautionary nature of the MMPA, therefore, NMFS cannot 
claim the lack of available information justifies its decision, and 
that NMFS has an affirmative obligation to find that impacts are no 
more than ``negligible'' and limited to the harassment of only ``small 
numbers of marine mammals.'' NSB notes that NMFS noted that the 
``continued lack of basic audiometric data for key marine mammal 
species'' that occur throughout the Chukchi Sea inhibits the ``ability 
to determine the nature and biological significance of exposure to 
various levels of both continuous and impulsive oil and gas activity 
sounds.''
    Response: While there may be some uncertainty on the current status 
of some marine mammal species in the Chukchi Sea and on impacts to 
marine mammals from seismic surveys, the best available information 
supports our findings. NMFS is currently proposing to conduct new 
population assessments for Arctic pinniped species, and current 
information is available on-line through the Stock Assessment Reports 
(SARs). Moreover, NMFS has required the industry to implement a 
monitoring and reporting program to collect additional information 
concerning effects to marine mammals.
    In regard to impacts, there is no indication that seismic survey 
activities are having a long-term impact on marine mammals. For 
example, apparently, bowhead whales continued to increase in abundance 
during periods of intense seismic activity in the Chukchi Sea in the 
1980s (Raftery et al. 1995; Angliss and Outlaw 2007), even without 
implementation of current mitigation requirements. As a result, NMFS 
believes that seismic survey noise in the Arctic will affect only small 
numbers of and have no more than a negligible impact on affected marine 
mammal species or stocks in the Chukchi Sea. As explained in this 
document and based on the best available information, NMFS has 
determined that Statoil's activities will affect only small numbers of 
marine mammal species or stocks, will have a negligible impact on 
affected species or stocks, and will not have an unmitigable adverse 
impact on subsistence uses of the affected species or stocks.
    Comment 10: AWL and NSB state that the standard for determining 
whether an IHA is appropriate is exceptionally protective. If there is 
even the possibility of serious injury, NMFS must establish that the 
``potential for serious injury can be negated through mitigation 
requirements'' (60 FR 28380; May 31, 1995). Reports from previous 
surveys, however, indicate that, despite monitored exclusion zones, 
marine mammals routinely stray too close to the airguns. AEWC states 
that the safety radii proposed by Statoil do not negate injury.
    Response: As has already been stated in the Federal Register notice 
for the proposed IHA (75 FR 32379; June 8, 2010), recent scientific 
information has indicated that received noise levels need to be 
significantly higher than 190 dB to cause injury to marine mammals (see 
Southall et al. 2007). Therefore, the 180- and 190-dB safety zones are 
conservative.
    The source vessel will be traveling at speeds of about 1-5 knots 
(1.9-9.3 km/hr). With a 180-dB safety range of 160 m (525 ft), the 
vessel will have moved out of the safety zone within a few minutes. As 
a result, during underway survey operations, MMOs are instructed to 
concentrate on the area ahead of the vessel, not behind the vessel 
where marine mammals would need to be voluntarily swimming towards the 
vessel to enter the 180-dB zone. In fact, in some of NMFS' IHAs issued 
for scientific seismic operations, shutdown is not required for marine 
mammals that approach the vessel from the side or stern in order to 
ride the bow wave or rub on the seismic streamers deployed from the 
stern (and near the airgun array) as some scientists consider this a 
voluntary action on the part of an animal that is not being harassed or 
injured by seismic noise. While NMFS concurs that shutdowns are not 
likely warranted for these voluntary approaches, in the Arctic Ocean, 
all seismic surveys are shutdown or powered down for all marine mammal 
close approaches. Also, in all seismic IHAs, including Statoil's IHA, 
NMFS requires that the safety zone be monitored for 30 min prior to 
beginning ramp-up to ensure that no marine mammals are present within 
the safety zones. Implementation of ramp-up is required because it is 
presumed it would allow marine mammals to become aware of the 
approaching vessel and move away from the noise, if they find the noise 
annoying. Data from 2007 and 2008, when Shell had support boats 
positioned 1 km (0.62 mi) on each side of the 3D seismic vessel, 
suggest that marine mammals do in fact move away from an active source 
vessel. In those instances, more seals were seen from the support 
vessels than were seen from the source vessels during active seismic 
operations. Additionally, research has indicated that some species tend 
to avoid areas of active seismic operations (e.g., bowhead whales, see 
Richardson et al. 1999).
    NMFS has determined that an IHA is the proper authorization 
required to cover Statoil's survey. As described in other responses to 
comments in this document, NMFS does not believe that there is a risk 
of serious injury or mortality from these activities. The monitoring 
reports from 2006, 2007, 2008, and 2009 do not note any instances of 
serious injury or mortality (Patterson et al. 2007; Funk et al. 2008; 
Ireland et al. 2009; Reiser et al. 2010). Additionally, NMFS is 
confident it has met all of the requirements of section 101(a)(5)(D) of 
the MMPA (as described

[[Page 49767]]

throughout this document) and therefore can issue an IHA to Statoil for 
its survey operations in 2010.
    Comment 11: AEWC notes that stranded marine mammals or their 
carcasses are also a sign of injury. NMFS states in its notice that it 
``does not expect any marine mammal will * * * strand as a result of 
the proposed seismic survey'' (75 FR 32379; June 8, 2010). In reaching 
this conclusion, NMFS claims that strandings have not been recorded for 
the Beaufort and Chukchi Seas. AEWC states that the Department of 
Wildlife Management of NSB has completed a study documenting 25 years 
worth of stranding data and showing that five dead whales were reported 
in 2008 alone in comparison with the five dead whales that were 
reported in the same area over the course of 25 years (Rosa 2009).
    In light of the increase in seismic operations in the Arctic since 
2006, AEWC says that NSB's study raises serious concerns about the 
impacts of these operations and their potential to injure marine 
mammals. AEWC states that while they think this study taken together 
with the June 2008 stranding of ``melon headed whales off Madagascar 
that appears to be associated with seismic surveys'' (75 FR 32379; June 
8, 2010) demonstrate that seismic operations have the potential to 
injure marine mammals beyond beaked whales (and that Statoil needs to 
apply for an LOA for its operations), certainly NSB's study shows that 
direct injury of whales is on-going. AEWC states that these direct 
impacts must be analyzed and explanations sought out before additional 
activities with the potential to injure marine mammals are authorized, 
and that NMFS must explain how, in light of this new information, 
Statoil's application does not have the potential to injure marine 
mammals.
    Response: NMFS has reviewed the information provided by AEWC 
regarding marine mammal strandings in the Arctic. The Rosa (2009) paper 
cited by AEWC does not provide any evidence linking the cause of death 
for the bowhead carcasses reported in 2008 to seismic operations. 
Additionally, the increased reporting of carcasses in the Arctic since 
2006 may also be a result of increased reporting effort and does not 
necessarily indicate that there were fewer strandings prior to 2008. 
Marine mammal observers (MMOs) aboard industry vessels in the Beaufort 
and Chukchi Seas have been required to report sightings of injured and 
dead marine mammals to NMFS as part of the IHA requirements only since 
2006.
    Regarding the June 2008 stranding of melon headed whales off 
Madagascar, information available to NMFS at this time indicates that 
the seismic airguns were not active around the time of the stranding. 
While the Rosa (2009) study does present information regarding the 
injury of whales in the Arctic, it does not link the cause of the 
injury to seismic survey operations. As NMFS has stated previously, 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 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 18 nm 
(33 km) at 1430 hrs. At 1300 hrs, the seismic vessel was located 25 nm 
(46 km) 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 18 nm (33 km). 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 the beaked whales to strand is a 
matter of considerable debate (see Cox et al. 2006). 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 IWC in 2004 (SC/
56/E28), mentioned a possible link between oil and gas seismic 
activities and the stranding of 8 humpback whales (7 off the Bahia or 
Espirito Santo States and 1 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.
    Additionally, 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 Statoil to ramp-up the seismic array to 
avoid a startle effect, strandings such as those observed in the 
Bahamas in 2000 are highly unlikely to occur in the Arctic Ocean as a 
result of seismic activity. Therefore, NMFS does not expect any marine 
mammals will incur serious injury or mortality as a result of Statoil's 
2010 survey operations, so an LOA is not needed.
    Lastly, Statoil is required to report all sightings of dead and 
injured marine mammals to NMFS and to notify the Marine Mammal Health 
and Stranding Response Network. However, Statoil is not permitted to 
conduct necropsies on dead marine mammals. Necropsies can only be 
performed by people authorized to do so under the Marine Mammal Health 
and Stranding Response Program MMPA permit. NMFS is currently 
considering different methods for marking carcasses to reduce the 
problem of double counting. However, a protocol has not yet been 
developed, so marking is not required in the IHA.
    Comment 12: AEWC, NSB, and Dr. Bain state that research is 
increasingly showing that marine mammals may remain within dangerous 
distances of seismic operations rather than leave a valued resource 
such as a feeding ground (see Richardson 2004). The International 
Whaling Commission (IWC) scientific committee has indicated that the 
lack of deflection by feeding whales in Camden Bay (during Shell 
Offshore Inc. and Shell Gulf of Mexico Inc.'s seismic activities) 
likely shows that whales will tolerate and expose themselves to 
potentially harmful levels of sound when needing to perform a 
biologically vital activity, such as feeding (mating, giving birth, 
etc.). Thus, the noise from Statoil's proposed operations could injure 
marine mammals if they are close enough to the source. NSB further 
states that NMFS has not adequately analyzed the potential for serious 
injury.

[[Page 49768]]

    Response: If marine mammals, such as bowhead whales, remain near a 
seismic operation to perform a biologically vital activity, such as 
feeding, depending on the distance from the vessel and the size of the 
160-dB radius, the animals may experience some Level B harassment. A 
detailed analysis on potential impacts of anthropogenic noise 
(including noise from seismic airguns and other active acoustic sources 
used in geophysical surveys) is provided in the proposed IHA (75 FR 
32379; June 8, 2010) and in this document. Based on the analysis, NMFS 
believes that it is unlikely any animals exposed to noise from 
Statoil's proposed marine surveys would be exposed to received levels 
that could cause TTS (a non-injurious Level B harassment). Therefore, 
it is even less likely that marine mammals would be exposed to levels 
of sound from Statoil's activity that could cause PTS (a non-lethal 
Level A harassment).
    In addition, depending on the distance of the animals from the 
vessel and the number of individual whales present, certain mitigation 
measures are required to be implemented. If an aggregation of 12 or 
more mysticete whales are detected within the 160-dB radius, then the 
airguns must be shutdown until the aggregation is no longer within that 
radius. Additionally, if any whales are sighted within the 180-dB 
radius or any pinnipeds are sighted within the 190-dB radius of the 
active airgun array, then either a power-down or shutdown must be 
implemented immediately. For the reasons stated throughout this 
document, NMFS has determined that Statoil's operations will not 
injure, seriously injure, or kill marine mammals.
    Comment 13: AEWC, AWL, and Dr. Bain state that NMFS does little to 
assess whether Level A harassment is occurring as a result of the 
deflection of marine mammals as a result of Statoil's proposed 
operations. Deflected marine mammals may suffer impacts due to masking 
of natural sounds including calling to others of their species, 
physiological damage from stress and other non-auditory effects, harm 
from pollution of their environment, tolerance, and hearing impacts 
(see Nieukirk et al. 2004). Not only do these operations disrupt the 
animals' behavioral patterns, but they also create the potential for 
injury by causing marine mammals to miss feeding opportunities, expend 
more energy, and stray from migratory routes when they are deflected.
    Response: See the response to comment 8 regarding the potential for 
injury. The paper cited by AEWC (Nieukirk et al. 2004) tried to draw 
linkages between recordings of fin, humpback, and minke whales and 
airgun signals in the western North Atlantic; however, the authors note 
the difficulty in assessing impacts based on the data collected. The 
authors also state that the effects of airgun activity on baleen whales 
is unknown and then cite to Richardson et al. (1995) for some possible 
effects, which AEWC lists in their comment. There is no statement in 
the cited study, however, about the linkage between deflection and 
these impacts. While deflection may cause animals to expend extra 
energy, there is no evidence that this deflection is causing a 
significant behavioral change that will adversely impact population 
growth. In fact, bowhead whales continued to increase in abundance 
during periods of intense seismic in the Chukchi Sea in the 1980s 
(Raftery et al. 1995; Angliss and Outlaw 2007). Therefore, NMFS does 
not believe that injury will occur as a result of Statoil's activities. 
Additionally, Statoil's total data acquisition activities would only 
ensonify 531 km\2\ of the Chukchi Sea to received levels above 160 dB 
(0.089% of the entire Chukchi Sea). Therefore, based on the small area 
of the Chukchi Sea where Statoil will utilize airguns, it is unlikely 
that marine mammals will need to expend much extra energy to locate 
prey, or will have reduced foraging opportunities.
    Comment 14: Citing Erbe (2002), AEWC notes that any sound at some 
level can cause physiological damage to the ear and other organs and 
tissues. Placed in a context of an unknown baseline of sound levels in 
the Chukchi Sea, it is critically important that NMFS take a 
precautionary approach to permitting additional noise sources in this 
poorly studied and understood habitat. Thus, the best available science 
dictates that NMFS use a more cautious approach in addressing impacts 
to marine mammals from seismic operations. AWL also states noise 
exposure is likely to result in stress, and stress can impair an 
animal's immune system.
    Response: The statement from Erbe (2002) does not take into account 
mitigation measures required in the IHA to reduce impacts to marine 
mammals. As stated throughout this document, based on the fact that 
Statoil will implement mitigation measures (i.e., ramp-up, power-down, 
shutdown, etc.), NMFS does not believe that there will be any injury or 
mortality of marine mammals as a result of Statoil's operations.
    Comment 15: AEWC states that in making its negligible impact 
determination, NMFS failed to consider several impacts: (1) Displacing 
marine mammals from feeding areas; (2) non-auditory, physiological 
effects, namely stress; (3) the possibility of vessel strikes needs to 
be considered in light of scientific evidence of harm from ship traffic 
to marine mammals; (4) impacts to marine mammal habitat, including 
pollution of the marine environment and the risk of oil spills, toxic, 
and nontoxic waste being discharged; (5) impacts to fish and other food 
sources upon which marine mammals rely; and (6) specific marine mammals 
that will be taken, including their age, sex, and reproductive 
condition. The first issue was also raised by Dr. Bain.
    Response: NMFS does not agree that these impacts were not 
considered. First, the area that would be ensonified by Statoil's 
proposed open water seismic surveys represents a small fraction of the 
total habitat of marine mammals in the Chukchi Sea. In addition, as the 
survey vessel is constantly moving, the ensonified zone where the 
received levels exceed 160 dB re 1 [mu]Pa (rms), which is estimated to 
be approximately 531 km\2\ at any given time, is constantly moving. 
Therefore, the duration during which marine mammals would potentially 
avoid the ensonified area would be brief. Therefore, NMFS does not 
believe marine mammals would be displaced from their customary feeding 
areas as a result of Statoil's proposed seismic surveys.
    Second, non-auditory, physiological effects, including stress, were 
analyzed in the Notice of Proposed IHA (75 FR 32379; June 8, 2010). No 
single marine mammal is expected to be exposed to high levels of sound 
for extended periods based on the size of the airgun array to be used 
by Statoil and the fact that an animal would need to swim close to, 
parallel to, and at the same speed as the vessel to incur several high 
intensity pulses. This also does not take into account the mitigation 
measures described later in this document.
    Third, impacts resulting from vessel strikes and habitat pollution 
and impacts to fish were fully analyzed in NMFS' 2010 Final EA for 
Shell and Statoil's open water marine and seismic activities (NMFS 
2010). Additionally, the proposed IHA analyzed potential impacts to 
marine mammal habitat, including prey resources. That analysis noted 
that while mortality has been observed for certain fish species found 
in extremely close proximity to the airguns, S[aelig]tre and Ona (1996) 
concluded that mortality rates caused by

[[Page 49769]]

exposure to sounds are so low compared to natural mortality that issues 
relating to stock recruitment should be regarded as insignificant. For 
the sixth point, please see the response to comment 4. The age, sex, 
and reproductive condition must be provided when possible. However, 
this is often extremely difficult to predict. Additional mitigation 
measures for bowhead cow/calf pairs, such as monitoring the 120-dB 
radius and requiring shutdown when 4 or more cow/calf pairs enter that 
zone, were considered and required for this survey.
    Comment 16: Stating that airgun noise can cause direct injury to 
marine mammals, Dr. Bain points out that (1) ``airgun arrays do not 
project noise equally in all directions,'' and that ``beams formed by 
the arrays can cause an animal moving from high exposure toward lower 
exposure to move toward the travel path of the seismic survey vessel, 
ultimately resulting in higher exposure;'' (2) ``the flight path of 
animals moving away is not always optimal. Animals may begin by 
swimming directly away from the array. However, if the array is moving 
toward them at faster than their sustained swimming speed, the array 
will approach them. After a while, animals may change tactics to moving 
orthogonal to the direction of array movement. While orthogonal 
movement will ultimately reduce the maximum noise level experienced, it 
allows the seismic survey vessel to close on their location faster. 
Shortly before the animals are orthogonal to the survey vessel, they 
may turn and head in the opposite direction of the survey vessel, 
briefly approaching it, but then increasing the distance between them 
at close to the highest possible rate;'' (3) if pinnipeds do not move 
away, ``the seismic survey vessel can approach them,'' that ``orienting 
behavior is interrupted with occasional swimming behavior. While the 
swims can increase the distance between the pinniped and the vessels 
track line, submerging exposes the ears to the full intensity of the 
received pulses''; (4) marine mammals may tolerate injury while 
feeding, because ``[f]ishers and NMFS personnel have shot animals and 
used seal bombs to inflict pain in unsuccessful efforts to deter 
depredation,'' and that ``predators sometimes swallow hooks along with 
their prey.''
    Response: While NMFS recognizes that intense noise exposure can 
cause direct harm to marine mammals, as discussed in the Federal 
Register for the proposed IHA (75 FR 32379; June 8, 2010) and in this 
document, the intensities of received levels need to be significantly 
higher or the exposure duration be significantly longer than those at 
issue here to cause TTS, let alone injury. Please refer to these 
documents and the EA for a detailed discussion on the noise impacts to 
marine mammals. The points Dr. Bain made in his comment do not support 
his argument. Regarding the first point, Dr. Bain is correct that 
airgun arrays do not project noise equally in all directions. As an 
airgun is designed to project its impulse downward, most of its 
acoustic energy is confined in downward beams. Although there is a 
significant amount of energy being propagated horizontally, especially 
close by, the intensity of noise is much less when compared to downward 
acoustic intensities. As acoustic energy travels from its source 
outwards, an animal moving from higher received levels to lower 
received levels is generally moving away from the source (the seismic 
airgun). At long distances where certain higher received levels form 
due to multi-path propagation and refraction, movement from higher 
received levels to lower received levels may not necessarily mean that 
the animal is moving away from the source. However, at this long 
distance, the received levels are expected to be much lower (below 160 
dB) and the distances are expected to be far beyond the zone of 
influence. This response also addresses part of Dr. Bain's second point 
regarding animal movement. In addition, the seismic vessel is 
prohibited from approaching marine mammals within specific safety zones 
(180 dB isopleths at 2,500 m for cetaceans and 190 dB isopleths at 700 
m for pinnipeds). Therefore, to address Dr. Bain's second and third 
points, regardless of whether animals are moving or not, the seismic 
vessel is not allowed to approach marine mammals within the designated 
safety zones. Finally, Dr. Bain's last point regarding the use of seal 
bombs to inflict pain and ``predators sometimes swallow hooks along 
with their prey,'' is irrelevant to our MMPA findings for Statoil's 
seismic activities. Statoil's activities do not involve the use of seal 
bombs and there is no connection between predators swallowing hooks 
along with their prey and the use of seismic airguns.
    Comment 17: Dr. Bain states that ``[b]ubble formation may be caused 
by moderate levels of noise. Rectified diffusion (Crum and Mao 1996) 
and decompression sickness (Jepson et al. 2003) are two postulated 
mechanisms for this. In rectified diffusion, acoustic energy causes gas 
to diffuse from the blood into small bubbles. Since bubbles are smaller 
when compressed, and larger when rarified, the net diffusion is into 
the bubble, leading to bubble growth in blood, fat, or other tissues, 
to injurious size.'' He also states that behaviorally mediated 
decompression sickness is considered more likely than rectified 
diffusion as the cause of bubble formation (Cox et al. 2006).
    Response: Although it has been suggested that bubble formation due 
to nitrogen gas bubble growth, resulting in effects similar to 
decompression sickness in humans (Jepson et al. 2003; Fern[aacute]ndez 
et al. 2004, 2005), may be the cause for at least some of the beaked 
whale mass strandings that occurred in association with mid-frequency 
active sonar operations, the hypothesis remains untested and the 
acoustic causative mechanism remains unknown today. In addition, the 
pathway concerning nitrogen supersaturation levels for deep-diving 
species of interest, including beaked whales, are based on theoretical 
models (Houser et al. 2001; Southall et al. 2007), and no unequivocal 
support for any of the pathways presently exists.
    Finally, the suspected bubble formation by acoustic sources, and 
the induced atypical diving pattern that are theorized to cause 
decompression sickness in deep diving marine mammals (such as beaked 
whales), were mostly speculated to be caused by tactical mid-frequency 
sonar associated with military exercises, not by airgun impulses from 
seismic surveys.
    Comment 18: While discussing impacts specific to the Chukchi Sea, 
Dr. Bain states that displacement from feeding areas is an even greater 
concern for harbor porpoises. Dr. Bain adds his personal observations 
that due to their small size, going without food for a few days can be 
fatal to harbor porpoises; and that harbor porpoises in Juan de Fuca 
Strait and Haro Strait experienced a doubling of mortality rates 
following exposure to a series of mid-frequency sonar exercise.
    Response: Dr. Bain did not provide any details to support his 
observations in the comments, and NMFS is not aware of any studies that 
support Dr. Bain's claim. Because there is no information showing that 
the doubling of mortality rate in harbor porpoises in Juan de Fuca 
Strait and Haro Strait is related to the mid-frequency sonar exercise, 
a causative relationship between the two cannot be derived.
    As discussed previously, due to the limited area (531 km\2\ for an 
area ensonified by received levels higher than 160 dB) that would be 
ensonified by the seismic airguns and the relatively short duration of 
the surveys (total of 60 days), and the constant movement of the

[[Page 49770]]

seismic vessel, it is unlikely that harbor porpoises or any other 
marine mammals would be displaced for any significant amount of time by 
the proposed open water seismic surveys. Therefore, even if marine 
mammals temporarily avoid an area that might be their feeding ground 
due to the seismic survey, the duration of the displacement is expected 
to be short, so that animals will not lose feeding opportunities for 
more than a few hours up to a day. In addition, the majority of sound 
sources from airgun arrays are in the low-frequency range, which is 
outside harbor porpoises' sensitive hearing range. Therefore, even 
though the intensities of seismic impulses are high, these impulses may 
not be perceived as intense noise by harbor porpoises due to their 
high-frequency hearing.
    Comment 19: AEWC states that in assessing the level of take and 
whether it is negligible, NMFS relied on flawed density estimates that 
call into question all of NMFS' preliminary conclusions. AEWC states 
that density data are lacking or outdated for almost all marine mammals 
that may be affected by Statoil's operations in the Chukchi Sea. AEWC 
argues that NMFS' guess at the number of beluga and bowhead whales 
relies on a study from Moore et al. (2000), which was ten years old. 
AEWC says that the estimate is contrary to the best available 
scientific information on beluga whale presence in the Chukchi Sea. 
AEWC points out that the most recent Alaska Marine Mammal Stock 
Assessment dates from 2009 and was issued in February 2010 (Allen and 
Angliss 2010), but Statoil's IHA application relied on the 2008 Alaska 
Marine Mammal Stock Assessment (Angliss and Allen 2009). AEWC further 
states that Allen and Angliss (2010) likely underestimated the size of 
the eastern Chukchi Sea beluga whale stock.
    AEWC also notes that the density of bowhead whales was derived from 
the same ten-year-old report (Moore et al. 2000) as was used to 
calculate beluga whale densities. AEWC points out that NMFS makes no 
mention of the most recent Alaska Marine Mammal Stock Assessment which 
was released this year, and that the Assessment cites to a 2003 study 
that documented bowheads ``in the Chukchi and Bering Seas in the 
summer'' that are ``thought to be a part of the expanding Western 
Arctic stock'' (Allen and Angliss 2010). While a study published in 
2003 still is not a sufficient basis for a 2009 density analysis, this 
study does show that additional information is available that indicates 
that the number of bowhead whales in the Chukchi may be higher than 
estimated by NMFS. NSB also points out that Statoil references aerial 
surveys conducted by Shell and ConocoPhilips between 2006 and 2008 
occurred exclusively in nearshore areas and not within Statoil's 
proposed operation area.
    Response: As required by the MMPA implementing regulations at 50 
CFR 216.102(a), NMFS has used the best scientific information available 
in assessing the level of take and whether the take by harassment will 
have a negligible impact on affect species or stocks. As far as the 
best scientific information is concerned, NMFS still considers Moore et 
al. (2000) to provide the best density estimate for the eastern Chukchi 
Sea population of beluga whales. The Alaska Marine Mammal Stock 
Assessment reports (Angliss and Allen 2009; Allen and Angliss 2010) do 
not report density estimates of the beluga whale population, they 
provide population estimates of marine mammal species and stocks. 
Furthermore, for the eastern Chukchi Sea stock of beluga whales, Allen 
and Angliss (2010) and Angliss and Allen (2009) provide the same 
average estimates of 3,710 individuals, therefore, even though Statoil 
used an earlier version of the Alaska Marine Mammal Stock Assessment 
Report, its number is the same as the 2010 report.
    Similarly, the Alaska Marine Mammal Stock Assessment only reports 
the abundance and population size, it does not provide density 
estimates of marine mammals in the proposed project area. The 2003 
study noted by AEWC in the bowhead whale Alaska Marine Mammal SAR 
discusses distribution, not density (Rugh et al. 2003). It was not 
cited because it is not useful for deriving density estimates. 
Therefore, density estimates for bowhead and beluga whales using Moore 
et al. (2000) are based on the best available science.
    Although most data used for marine mammal density are from Moore et 
al. (2000), information from other sources, wherever available, such as 
aerial surveys conducted by Shell and ConocoPhilips between 2006 and 
2008 (Haley et al. 2009), were also used to fill data gaps.
    Comment 20: AEWC states that NMFS fails to explain how and why it 
reaches various conclusions in calculating marine mammal densities and 
what the densities are actually estimated to be once calculated. One 
example is NMFS' reliance on Moore et al. (2000) in making its density 
determinations. This study documented sightings of marine mammals but 
did not estimate the total number of animals present. AEWC states that 
NMFS's practices have resulted in entirely arbitrary calculations of 
the level of take of marine mammals and whether such takes constitute 
``small numbers'' or a ``negligible impact'' as a result of Statoil's 
proposal.
    Response: All densities used in calculating estimated take of 
marine mammals based on the described operations are shown in Tables 2 
and 3 of Statoil's application. Moore et al. (2000) provides line 
transect effort and sightings from aerial surveys for cetaceans in the 
Chukchi Sea. Species specific correction factors for animals that were 
not at the surface or that were at the surface but were not sighted 
[g(0)] and animals not sighted due to distance from the survey 
trackline [f(0)] used in the equation were taken from reports or 
publications on the same species or similar species (if no values were 
available for a given species) that used the same survey platform. 
Additional explanations regarding the calculations of marine mammal 
densities are provided in Statoil's application and the Federal 
Register notice for the proposed IHA (75 FR 32379; June 8, 2010). 
Therefore, NMFS believes the methodology used in take calculations of 
the level of take of marine mammals is scientifically well supported.
    Comment 21: AEWC is opposed to NMFS using ``survey data'' gathered 
by industry while engaging in oil and gas related activities and 
efforts to document their take of marine mammals. AEWC points out that 
such industry ``monitoring'' is designed to document the level of take 
occurring from the operation (see 75 FR 32379 and Statoil's 4MP). AEWC 
argues that putting aside whether the methodologies employed are 
adequate for this purpose, they certainly are not adequate for 
assessing the density or presence of marine mammals that typically 
avoid such operations.
    Response: In making its determinations, NMFS uses the best 
scientific information available, as required by the MMPA implementing 
regulations. For some species, density estimates from sightings 
surveys, as well as from ``industry surveys'', were provided in the 
text of Statoil's application and the Notice of Proposed IHA for 
purposes of comparison. However, where information was available from 
sightings surveys (e.g., Moore et al. 2000; Bengtson et al. 2005), 
those estimates were used to calculate take. Data collected on industry 
vessels were only used when no other information was available. 
Additionally, while some Arctic marine mammal species have shown 
fleeing responses to seismic airguns, data is also collected on

[[Page 49771]]

these vessels during periods when no active seismic data collection is 
occurring.
    Comment 22: AEWC states that as a general matter, when it comes to 
NMFS assessing the various stocks of marine mammals under the MMPA, it 
cannot use outdated data i.e., ``abundance estimates older than 8 
years'' because of the ``decline in confidence in the reliability of an 
aged abundance estimate'' (Angliss and Allen 2009) and the agency is 
thus unable to reach certain conclusions. Similarly, here, where data 
are outdated or nonexistent, NMFS should decide it cannot reach the 
necessary determinations. AEWC argues that these flaws in NMFS' 
analysis render the agency's preliminary determinations about the level 
of harassment and negligible impacts completely arbitrary.
    Response: The statements quoted by AEWC from Angliss and Allen 
(2009) are contained in species SARs where abundance estimates are 
older than 8 years. However, the full statement reads as follows: 
``However, the 2005 revisions to the SAR guidelines (NMFS 2005) state 
that abundance estimates older than 8 years should not be used to 
calculate PBR due to a decline in confidence in the reliability of an 
aged abundance estimate.'' Statoil's activities are not anticipated to 
remove any individuals from the stock or population. Therefore, a 
recent estimate of PBR is not needed for NMFS to make the necessary 
findings under Section 101(a)(5)(D) of the MMPA. Additionally, 
Statoil's application provides information (including data limitations) 
and references for its estimates of marine mammal abundance. Because 
AEWC has not provided information contrary to the data provided by 
Statoil, and NMFS does not have information that these estimates are 
not reliable, NMFS considers these data to be the best available.
    Comment 23: Dr. Bain states that standard terminology in the field 
of density estimates is not used in density estimates, specifically 
citing the use of f(0). Dr. Bain recommends that an f(0) should be 
calculated from the data when there is a reference to 891 ``transect'' 
sightings of bowheads and that these sightings should have been used in 
Distance to calculate an f(0) for bowheads and states that it is 
reasonable to assume this has already been done. Dr. Bain states that 
log-normal confidence limits should be used when calculating the 
densities and that the upper confidence limits should be used as the 
point estimate in the take calculations. Dr. Bain recommends that 
double-platform trials should be run in Distance to better estimate 
g(0).
    Response: The traditional f(0) parameter and terminology are used 
throughout the density estimate descriptions in Statoil's application.
    However, there is no reference given for the 891 ``transect'' 
sightings which would allow an evaluation of whether or not the 
associated covariates suggested by Dr. Bain are available for the 
recommended analysis. Also, Dr. Bain did not provide a reference for 
the results of such an analysis that he suggests are reasonable to 
assume exist.
    The equations for the calculation of log-normal confidence limits 
are provided and an example using ``three point estimates of summertime 
density of bowhead whales'' is shown. However, there is no indication 
of where the three point estimates of summertime densities came from 
and values in the application do not combine to replicate the estimate 
provided. Using the upper confidence limits of an estimate is an 
extremely conservative approach on top of already conservative 
assumptions regarding received sound levels. Maximum densities and 
associate take estimates provided in the application are meant to 
provide upper estimates similar to those suggested from using the upper 
confidence limits. Basing decisions on take estimates from the upper 
confidence limits is, as Dr. Bain points out, extremely precautionary, 
and NMFS does not believe it represents the best available scientific 
approach.
    Since no reference is given for such double-platform data on 
bowheads. NMFS is not aware of the existence or availability of 
sufficient data from double-platform trials while surveying bowheads to 
do the recommended analysis. Collection of an adequate dataset would 
likely require multiple years of aerial surveys using two observers on 
each side of the aircraft that collect data independently of each 
other, which is impracticable due to the scope and scale of the 
research. Nevertheless, based on available data and analysis, NMFS 
believes that existing datasets are adequate to address the degrees and 
levels of potential impacts to marine mammals as a result of the 
proposed seismic surveys in the project vicinity.
    Comment 24: Dr. Bain points out that use of the statistical method 
for incorporating uncertainties is trivial. He further states that the 
data were inappropriately split to estimate densities and that the raw 
data should have been analyzed using multivariate modeling approaches 
available in Distance.
    Response: As suggested by Dr. Bain, incorporating uncertainty 
associated with various parameters in a density estimate is relatively 
easier when working with actual raw survey data by using the Distance 
software. However, data or analyses of the type suggested on the 
relevant species at the location and time of the proposed project are 
not available. Estimates of uncertainty are not necessarily available 
for all parameters found in the literature that were used to calculate 
estimated densities. Although incorporating all parameters and 
associated uncertainties into a single framework would indeed be a good 
approach, it would not be practical for an applicant to conduct 
analyses in such detail and large scale. As stated earlier, NMFS 
believes that existing datasets are adequate to address the degrees and 
levels of potential impacts to marine mammals as a result of the 
proposed seismic surveys in the project vicinity.
    As for the final point, data ``splits'' used in the application 
were based on a published article and the necessary data to do the 
analysis as Dr. Bain suggested using Distance are not available.
    Comment 25: Commenting on Southall et al. (2007), Dr. Bain states 
that Southall et al.'s review relied on published reports, and they 
were selective for datasets reported in a way that fit their 
categorization scheme. Dr. Bain points out that other workers have 
access to raw data and can rescore behavioral responses using Southall 
et al.'s system (e.g., Bain and Williams in review). Dr. Bain further 
states that he found that the approach of generalizing responsiveness 
based on morphological group, such as pinnipeds, high-frequency hearing 
specialists (small odontocetes), low-frequency specialists 
(mysticetes), etc., unlikely to be valid, as sibling species such as 
Dall's and harbor porpoises differed dramatically in their responses to 
noise from the same airguns in the same geographic area, and harbor 
porpoises appeared more responsive to airguns than low-frequency 
specialists like gray whales.
    Response: NMFS does not agree with Dr. Bain's assessment on 
Southall et al.'s review. First, the central purpose of the Southall et 
al. (2007) paper is to propose, for various marine mammal groups and 
sound types, levels above which there is a scientific basis for 
expecting that exposure would cause auditory injury to occur. Although 
behavioral or electrophysiological audiograms only exist for 
approximately 20 marine mammal species (of ~128 species and subspecies; 
Rice 1998), however, since physiological effects of

[[Page 49772]]

the auditory structure, i.e., TTS or PTS, are closely related to the 
frequency ranges of acoustic signals that are sensitive to a particular 
audio-physiology mechanism, by combining audiograms of known marine 
mammal species with comparative anatomy, modeling, and response 
measured in ear tissues from species that are difficult to study, it is 
a valid approach to classify marine mammal hearing based on their 
functional hearing groups. Although the current classification of five 
functional hearing groups (i.e., low-frequency cetacean, mid-frequency 
cetacean, high-frequency cetacean, pinnipeds in water, and pinnipeds in 
air) is still in its initial stage, and further improvements are no 
doubt needed as more scientific information becomes available, these 
improvements are likely to be focusing on refining the current 
groupings (e.g., dividing pinnipeds into otariids and phocids). NMFS 
considers the use of these functional hearing groups in addressing 
physiological effects and hearing impairment a valid approach.
    Second, as far as behavioral effects are concerned, Southall et al. 
(2007) admits that ``the available data on behavioral responses do not 
converge on specific exposure conditions resulting in particular 
reactions, nor do they point to a common behavioral mechanism.'' They 
further points out that ``[i]t is clear that behavioral responses are 
strongly affected by the context of exposure and by the animal's 
experience, motivation, and conditioning.'' Therefore, behavioral 
responses to external stimuli may not be able to be addressed just 
based on received levels. For example, in Bain and Williams (in review) 
it is stated that Dall's porpoises were ``observed at received levels 
up to approximately 180 dB re 1 [mu]Pa p-p,'' while harbor porpoises 
were ``recorded at received levels up to 155 dB re 1 [mu]Pa p-p, and 
all individuals were moving away at this level,'' it is possible that a 
major factor causing the harbor porpoises to move away was the 
researchers' vessel that was closely approaching the animals at 
approximately 20 km/h. We believe a more rigorously designed controlled 
exposure experiment or behavioral response study is required to obtain 
unbiased data to address behavioral responses of marine mammals to 
anthropogenic sound. For this reason, studies used in the Southall et 
al. (2007) review were carefully selected to include studies where 
``noise exposure (including source and received levels, frequency, 
duration, duty cycle, and other factors) was either directly reported 
or was reasonably estimated using simple sound propagation models 
deemed appropriate for the sources and operational environment'' 
(Southall et al. 2007).
    Nevertheless, for regulatory purposes, NMFS has been using 160 dB 
re 1 [mu]Pa (rms) as the onset for behavioral harassment when exposed 
by impulse sources. The basis for choosing received levels 
corresponding to the onset of behavioral harassment came from many 
field observations and analyses (see review by Richardson et al. 1995; 
Southall et al. 2007) that NMFS considers representative in many 
situations.
    Comment 26: Dr. Bain states that changes in behavior resulting from 
noise exposure could lead to injury or death through a number of 
mechanisms, and he gave the example that ``hearing loss due to PTS or 
TTS may prevent animals from detecting approaching vessels, leading to 
collisions between marine mammals and vessels,'' and that such 
collisions are often ultimately fatal, and that hearing loss may also 
lead to entanglement and increased risk of predation. Dr. Bain states 
that hearing ability can also be impaired during exposure to low levels 
of noise, causing masking. Dr. Bain also points out that another 
behavioral response to noise is flight, and that ``flight can result in 
stranding (NOAA and Navy 2001), or extreme exhaustion resulting in 
muscle damage or heart failure (Williams and Thorne 1996).''
    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, such as the hypothesized 
atypical diving patterns that may be exhibited by beaked whales when 
exposed to military tactical mid-frequency sonar, as discussed earlier 
and in NOAA and Navy (2001) cited by Dr. Bain in his comment. However, 
in most cases, changes in behavior resulting from noise exposure do not 
lead to PTS or TTS as apparently assumed by Dr. Bain in his comment. 
Additionally, as discussed in the Federal Register notice for the 
proposed IHA and in this document, marine mammals exposed to the 
proposed Statoil seismic surveys are not expected to experience TTS or 
PTS with the implementation of appropriate monitoring and mitigation 
measures. Furthermore, the assumption that Dr. Bain made that 
``exhaustion from rapid flight leading to heart or other muscle 
damage'' could account for mortality merely because of exposure to 
airgun noise has no scientific basis.
    For issues regarding behavioral change and masking by the proposed 
Statoil seismic surveys, NMFS does not believe that received SPLs from 
the airgun arrays would cause drastic changes in behavior or auditory 
masking in marine mammals outside the safety zones. Unlike military 
sonar, seismic pulses have an extremely short duration (tens to 
hundreds of milliseconds) and relatively long intervals (several 
seconds) between pulses. Therefore, the sound energy levels from these 
acoustic sources 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. Although airgun pulses at long distances 
(over kilometers) may be ``stretched'' in duration and become non-pulse 
due to multipath propagation, the intervals between the non-pulse 
noises would still allow biologically important signals to be detected 
by marine mammals. In addition, NMFS requires mitigation measures to 
ramp-up acoustic sources at a rate of no more than 6 dB per 5 min. This 
ramp-up would prevent marine mammals from being exposed to high levels 
of noise without warning, thereby eliminating the possibility that 
animals would dramatically alter their behavior (i.e. from a 
``startle'' reaction).
    Comment 27: Citing research on long term adverse effects to whales 
and dolphins from whale watching activities (Trites and Bain 2000; Bain 
2002; Lusseau et al. 2009), 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, those examples do not reflect the 
impacts of seismic surveys to marine mammals for Statoil's 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

[[Page 49773]]

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, Statoil's proposed seismic survey, along with 
existing industrial operations in the Arctic Ocean, does not 
intentionally approach marine mammals in the project areas. Statoil's 
survey locations are situated in a much larger Arctic Ocean Basin, 
which is far away from most human impacts. Therefore, the effects from 
each activity are remote and spread farther apart, as analyzed in NMFS' 
2010 EA, as well as the MMS 2006 PEA. Statoil's seismic activities 
would only be conducted between late July and October for about 60 
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 marine mammals exposed to chronic sound 
from whale watching vessels, as cited by Dr. Bain. Therefore, NMFS 
believes that potential impacts to marine mammals in the Chukchi Sea by 
seismic surveys would be limited to Level B harassment only, and due to 
the limited scale and remoteness of the project in relation to a large 
area, such adverse effects would not accumulate to the point where 
biologically significant effects would be realized.
    Comment 28: Dr. Bain notes that NMFS uses different thresholds for 
continuous and pulsed sounds, and that ``NMFS based its use of a 120 dB 
contour for continuous sounds primarily on studies of bowheads and gray 
whales.'' Dr. Bain observes that ``these studies were conducted based 
on whales close to noise sources,'' and the ``120 dB contour was 
commonly the level at which 50% of the animals exposed to noise showed 
observable changes in behavior, such as deflection of the travel path 
away from the source.'' Dr. Bain states that there are two problems 
with this interpretation of the data: (1) This implies that 50% of the 
whales observed responded to levels lower than 120 dB. That is, 120 dB 
is not a threshold for a species but a median value of thresholds of 
individuals. The likelihood that individuals will be taken by exposure 
to noise levels below 120 dB declines with received level, but does not 
approach 0 until the received level approaches the limit of audibility; 
and (2) individuals that responded to levels much lower than 120 dB 
were not included in these studies, as they did not approach close 
enough to be observed. NSB also states that bowhead whales showed 
almost total avoidance of an area around seismic surveys where received 
sound levels were greater than 120 dB (LGL Ltd. and Greenridge Sciences 
1999), and that since the ensonified area for 120 dB is huge, the 
entire bowhead population could be affected.
    Response: Since Dr. Bain did not provide any reference in his 
comment, the validity of his notes and observation cannot be verified. 
However, NMFS is not aware of the ``use of a 120 dB contour for 
continuous sounds'' on any marine mammal species. The basis for 
choosing received levels corresponding to the onset of behavioral 
harassment came from many field observations and analyses (see review 
by Richardson et al. 1995; Southall et al. 2007) on measured avoidance 
responses in whales in the wild. It is also important to know that NMFS 
uses different received levels for behavioral harassment caused by 
impulse and non-impulse noises (i.e., received level at 160 dB re 1 
[micro]Pa for impulse and 120 dB re 1 [mu]Pa for non-impulse). To be 
specific, the 160 dB re 1 [mu]Pa (rms) threshold was derived from data 
for mother-calf pairs of migrating gray whales (Malme et al. 1983; 
1984) and bowhead whales (Richardson et al. 1985; Richardson et al. 
1986) responding when exposed to seismic airguns (impulsive sound 
source). The 120 dB re 1 [mu]Pa (rms) threshold also originates from 
research on baleen whales, specifically migrating gray whales (Malme et 
al. 1984; predicted 50% probability of avoidance) and bowhead whales 
reacting when exposed to industrial (i.e., drilling and dredging) 
activities (non-impulsive sound source) (Richardson et al. 1990).
    Second, Dr. Bain confused ``take'' under the MMPA with any observed 
behavioral response. A ``take'' by 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'' (emphasis added). A brief startling response without 
subsequent change of the animal's ongoing behavioral pattern, for 
example, does not constitute a ``take'' under the definition of MMPA. 
Therefore, marine mammals that briefly respond to certain received 
noise levels may not be ``taken,'' as long as there is no disruption of 
their behavioral patterns.
    Finally, as stated above, received levels at 160 dB re 1 [mu]Pa is 
currently used by NMFS as the onset of behavioral harassment for 
impulses, and source characteristics from airgun arrays are classified 
as impulses. Therefore, the 120 dB continuous noise discussion in Dr. 
Bain's comment is inapplicable.
    Comment 29: Citing works by Calambokidis et al. (1998) and Bain and 
Williams (in review) on impacts of marine mammal behavioral by seismic 
surveys, Dr. Bain states that harbor porpoises are more likely to be 
affected by lower received levels than other cetaceans. Dr. Bain states 
that he believes ``the segregation of population by noise tolerance 
(and physical ability to avoid the noise source) provides an 
explanation for why some studies detect marine mammals close to noise 
sources, and other show responses to received levels in the 
neighborhood of 90 dB or less at great distance.'' Dr. Bain further 
states that future work will be needed to elucidate nuances of how 
those probabilities are influenced by non-noise factors such as 
location, activity state, or individual factors like age, sex, 
reproductive status, health status, group composition, and previous 
experience with noise exposure. Dr. Bain concludes that ``bowhead and 
gray whales can be expected to respond out to the 120 dB contour, with 
more sensitive individuals perhaps responding at the 105 dB contour. 
Killer whales and belugas would be expected to respond at the 105 dB 
contour, with the need for social cohesion resulting in less 
variability in response than seen in bowheads and grays. Harbor 
porpoises are likely to exhibit responses out to the level of 
detection, as they have been shown to respond to received noise below 
90 dB in quiet water.''
    Response: NMFS agrees that behavioral responses by marine mammals 
to noise sources vary with species, population, behavioral context, 
age, sex, and source characteristics, etc., and NMFS has been looking 
into these factors and is supporting research such as behavioral 
response studies (BRS) at the Atlantic Undersea Test and Evaluation 
Center (AUTEC) in the Bahamas, the Mediterranean Sea, and off southern 
California to elucidate factors that could induce behavioral responses 
on cetaceans by various noise sources, particularly by military sonar. 
Nevertheless, at the current stage, as stated above, NMFS still uses 
the 120 dB and 160 dB re 1 [mu]Pa as the threshold for the onset of 
behavioral harassment

[[Page 49774]]

for non-impulse and impulse noise sources, respectively. Based on many 
field studies and observations (see review by Richardson et al. 1995; 
Southall et al. 2007), NMFS believes that these thresholds are 
conservative and can provide relatively fair estimates of marine 
mammals potentially subject to harassment.
    Dr. Bain did not provide any reference to support his claim that 
``bowhead and gray whales can be expected to respond out to the 120 dB 
contour, with more sensitive individuals perhaps responding at the 105 
dB contour. Killer whales and belugas would be expected to respond at 
the 105 dB contour, with the need for social cohesion resulting in less 
variability in response than seen in bowheads and grays. Harbor 
porpoises are likely to exhibit responses out to the level of 
detection, as they have been shown to respond to received noise below 
90 dB in quiet water.'' Additionally, Dr. Bain did not provide what 
these responses are and whether they meet the definition of ``takes'' 
under the MMPA.
    Comment 30: Citing his manuscript (Bain and Williams, in review) on 
effects of large airgun arrays on the behavior of marine mammals at 
long distances in the waters of British Columbia, Canada and Washington 
State, USA, Dr. Bain argues that marine mammals can be taken at much 
lower received levels, and states that NMFS underestimated take numbers 
of marine mammals.
    Response: NMFS reviewed Dr. Bain's attached manuscript (Bain and 
Williams, in review), which was attached with his comments. The paper 
examines the effects of large airgun arrays on behavior of marine 
mammals in the waters of British Columbia, Canada and Washington State, 
USA, using a small boat to monitor out to long ranges (1 to > 70 km 
from the seismic source vessel), and contains some information 
concerning marine mammals that were apparently affected by the seismic 
survey. The paper, which was originally presented at the IWC meeting in 
2006, concludes that a significant relationship was observed between 
the magnitude of behavioral response and peak-to-peak received level 
and the long distances at which behavioral responses were observed (> 
60 km for harbor porpoise), along with counter-productive behavior that 
occasionally brought individuals into higher-intensity acoustic zones. 
However, there are potential design flaws in this study. First, the 
paper states a launch carried aboard the seismic receiver vessel was 
placed in the water to perform received level measurements near marine 
mammals. When making acoustic measurements, the launch ``travelled 
along a line at approximately 20 km/h until either marine mammals were 
closely approached, or the launch had travelled 10 km.'' Therefore, it 
is highly likely that behavioral reactions from observed marine mammals 
were caused by the high-speed, close-approach of the launch, rather 
than from distant seismic airguns. This experiment design may explain 
the authors' observation of ``counter-productive behavioral responses'' 
that animals are moving into higher-intensity acoustic zones, which 
probably indicates that behavioral changes caused by Bain's launch 
greatly exceeded any behavioral change resulting from exposure to 
seismic airgun noise. Second, the authors of the paper also expressed 
``methodological concerns due to the subjectivity of observers.'' 
Nevertheless, this study (Bain and Williams, in review) concludes that 
harbor seal individuals were generally moving away from the airguns at 
exposure levels above 170 dB re 1 [mu]Pa (p-p) and that gray whales 
were observed at received levels up to approximately 170 dB re 1 [mu]Pa 
(p-p) exhibiting no obvious behavioral response. These observations 
contradict Mr. Bain's earlier comments that major behavioral effects 
result from noise in the 105--125 dB range.
    Finally, Bain and Williams (in review) also state that the study 
``found that while airguns concentrated their sound output at low 
frequencies, substantial high frequency energy (to at least 100 kHz) 
was also present.'' However, the paper provides no explanation as to 
how this conclusion was made. The accompanying power density spectrum 
(Figure 2 in Bain and Williams, in review) of the paper fails to show 
evidence that the frequencies above 1 kHz were mostly contributed from 
seismic airguns, and there was no indication at what distance this 
recording was made. Therefore, Bain and Williams (in review) cannot be 
used to interpret marine mammal behavioral reactions to long distance 
seismic sources because it fails to provide a valid argument that the 
behavioral reactions by observed marine mammals are from seismic noises 
and that the acoustic energy of the recorded broadband received levels 
(up to 100 kHz) is entirely from seismic airguns.
    Comment 31: Stating marine mammal takes could occur at received 
levels at 90 dB, Dr. Bain claims that he used the applicant's equation 
of RL = 157.2 - 35.3 LOG (R/10000) - 0.0000064 (R - 10000) to estimate 
the distance to the 135 dB, 120 dB, 105 dB, and 90 dB contours, and 
showed that the best fit distances of these isopleths to be 42000, 
110000, 270000, and 620000 (no units given), respectively, with 
relative areas at 10, 72, 431, and 2274 (no units given), respectively; 
the 90th percentile distances of these isopleths to be 45000, 116000, 
285000, and 650000 (no units given), respectively, and the relative 
areas of these isopleths to be 12, 80, 311, and 2500 (no units given), 
respectively. In comparison, Statoil's estimated received level at 120-
dB isopleths is 70-120 km from the source (75 FR 32379; June 8, 2010).
    Response: First, Statoil did not use the equation in Dr. Bain's 
comment for the estimates of distances to safety zones (180-dB and 190-
dB re 1 [mu]Pa for cetaceans and pinnipeds, respectively) and zone of 
influence (160-dB re 1 [mu]Pa isopleths). As stated in Statoil's IHA 
application and in the Federal Register notice for the proposed IHA (75 
FR 32379; June 8, 2010), the basis for the estimation of distances to 
the four received sound levels (190 dB, 180 dB, 160 dB, and 120 dB re 1 
[mu]Pa) from the proposed 3000 in\3\ airgun array operating at a depth 
of 20 ft (6 m) are the 2006, 2007 and 2008 sound source verification 
(SSV) measurements in the Chukchi Sea of a similar array, towed at a 
similar depth. The measured airgun array had a total discharge volume 
of 3,147 in\3\ and was composed of three identically-tuned Bolt airgun 
sub-arrays, totaling 24 airguns (6 clusters of 2 airguns and 12 single 
airguns). The proposed 3,000 in\3\ array is also composed of three 
strings with a total of 26 active airguns in 13 clusters (five clusters 
of 10 airguns are inactive and will be used as spares). The difference 
in discharge volume would lead to an expected loss of less than 0.2 dB 
and is neglected in this assessment. The estimated source level for the 
full 3,000 in\3\ array is 245 dB re 1 [mu]Pa (rms). Before SSV tests 
could be conducted for the 3,000 in\3\ array that would be used for the 
proposed seismic survey, it is reasonable to adopt the maximum 
distances obtained from a similar array during previous measurements in 
the Chukchi Sea. Therefore, the distances to received levels of 190, 
180 160, and 120 dB re 1 [mu]Pa (rms) are conservatively estimated at 
700, 2,500, 13,000, and 70,000-120,000 m, respectively. The only 
propagation equation Statoil used in estimating the zones of different 
isopleths is the one used to calculate the safety zones and zone of 
influence for the 60 in\3\ mitigation gun, which was adjusted by adding 
3 dB. The term of the equation is:


[[Page 49775]]


RL = 226.6 - 21.2log(R) - 0.00022R, where R is distance in m.

    Second, based on the equation Dr. Bain provided, NMFS calculated 
the distances to 190 and 180-dB received levels at 1,180 m and 2,260 m, 
respectively, which are very different from what Dr. Bain reported at 
370 and 1,100 (units not given), respectively, for ``best fit'', and 
450 and 1,400 (units not given), respectively, for ``90th percentile.'' 
Finally, without field measurements, NMFS does not know, and Dr. Bain 
did not explain, how the ``best fit'' and ``90th percentile'' were 
calculated.
    Comment 32: Dr. Bain states that recent declines in gray whale 
populations have resulted in the population dropping below the level at 
which they were delisted, and that emaciation has been observed in many 
gray whales that have stranded this year, so exclusion from potential 
feeding grounds is of extra concern this year. Further, Dr. Bain states 
that harbor porpoises can be affected at large distances from noise 
sources, and hence large numbers would be expected to be affected by 
this and other activities. He points out that although NMFS currently 
recognizes only a single, large stock whose range includes the project 
area, genetic and movement studies in other parts of the harbor 
porpoise range have shown that stocks tend to be much smaller and have 
limited ranges. Finally, Dr. Bain points out that cumulative effects on 
belugas and other species are likely to have been underestimated 
because the ``greater range at which they are likely to be affected and 
the potential for greater overlap between the project activities and 
migration through the area than considered by NMFS for this and the 
shallow water survey make this the case.''
    Response: Systematic counts of Eastern Pacific gray whales 
migrating south along the central California coast have been conducted 
by shore-based observers at Granite Canyon most years since 1967. The 
most recent abundance estimates are based on counts made during the 
1997-98, 2000-01, and 2001-02 southbound migrations. Analyses of these 
data resulted in abundance estimates of 29,758 for 1997-98, 19,448 for 
2000-01, and 18,178 for 2001-02 (Rugh et al. 2005). NMFS is aware of 
the 2000-01 and 2001-02 population drops in the gray whales, 
nevertheless, to a certain degree, variations in estimates may be due 
in part to undocumented sampling variation or to differences in the 
proportion of the gray whale stock migrating as far as the central 
California coast each year (Hobbs and Rugh 1999). The decline in the 
2000-01 and 2001-02 abundance estimates may be an indication that the 
abundance was responding to environmental limitations as the population 
approaches the carrying capacity of its environment (Allen and Angliss 
2010). Low encounter rates in 2000-01 and 2001-02 may have been due to 
an unusually high number of whales that did not migrate as far south as 
Granite Canyon or the abundance may have actually declined following 
high mortality rates observed in 1999 and 2000 (Gulland et al. 2005). 
Visibly emaciated whales (LeBoeuf et al. 2000; Moore et al. 2001) 
suggest a decline in food resources, perhaps associated with unusually 
high sea temperatures in 1997 (Minobe 2002). Several factors since this 
mortality event suggest that the high mortality rate was a short-term, 
acute event and not a chronic situation or trend: (1) Counts of 
stranded dead gray whales dropped to levels below those seen prior to 
this event, (2) in 2001 living whales no longer appeared to be 
emaciated, and (3) calf counts in 2001-02, a year after the event 
ended, were similar to averages for previous years (Rugh et al. 2005). 
Though it is impractical to exclude the proposed Statoil seismic survey 
entirely from the gray whale feeding areas (such as areas near Hanna 
Shoal), as discussed in the Federal Register notice for the proposed 
IHA (75 FR 32379; June 8, 2010) and in this document, the potential 
impacts to gray whales (and other marine mammals) is expected to be 
negligible. In addition, mitigation and monitoring measures described 
below would further reduce the potential impacts. Lastly, Statoil's 
surveys are not expected to destroy or result in any permanent impact 
on habitats used by gray whales or to their prey resources or to 
jeopardize the continued existence of the species.
    Since delisting gray whales in 1994, NMFS has continued to monitor 
the status of the population consistent with its responsibilities under 
the ESA and the MMPA. In 1999, a NMFS review of the status of the 
eastern North Pacific stock of gray whales recommended the continuation 
of this stock's classification as nonthreatened (Rugh et al. 1999). 
Workshop participants determined the stock was not in danger of 
extinction, nor was it likely to become so in the foreseeable future. 
In 2001 several organizations and individuals petitioned NMFS to re-
list the eastern North Pacific gray whale population. NMFS concluded 
that there were several factors that may be affecting the gray whale 
population but there was no information indicating that the population 
may be in danger of extinction or likely to become so in the 
foreseeable future. Wade and Perryman (2002) and Punt et al. (2004) 
(cited in the 2008 SAR, Angliss and Allen 2009) found that the stock is 
within its optimum sustainable population level and that the population 
is likely close to or above its unexploited equilibrium level. NMFS 
continues to monitor the abundance of the stock through the MMPA stock 
assessment process, especially as it approaches its carrying capacity. 
If new information suggests a reevaluation of the eastern North Pacific 
gray whales' listing status is warranted, NMFS will complete the 
appropriate reviews.
    Without scientific support, NMFS does not agree with Dr. Bain's 
assumption that ``harbor porpoises can be affected at large distances 
from noise sources, and hence large numbers would be expected to be 
affected by this and other activities.'' Due to the lack of robust 
field studies and observations, behavioral responses of harbor 
porpoises (a species in the ``high-frequency cetacean'' functional 
hearing group) to impulse noise sources such as those generated by 
airguns are poorly known. Given that they are high-frequency cetaceans, 
harbor porpoises are not considered to be sensitive to low frequency 
noise sources when compared to bowhead whales (which are ``low-
frequency cetaceans'' species). However, NMFS currently uses 160 dB re 
1 [mu]Pa (rms) as the threshold for the onset of behavioral harassment 
for all marine mammals. Therefore, NMFS believes its method for 
calculating takes of harbor porpoises using 160 dB re 1 [mu]Pa (rms) is 
reasonable.
    Whether harbor porpoises occurring in Alaska waters belong to one 
single, large stock is still under scientific debate. Nevertheless, at 
this time, no data are available to reflect stock structure for harbor 
porpoise in Alaska, and for management purposes, NMFS Alaska Marine 
Mammal Stock Assessment reports consider only one Alaska stock of 
harbor porpoise (Allen and Angliss 2010). Should new information on 
harbor porpoise stocks become available, the harbor porpoise Stock 
Assessment Reports will be updated.
    Finally, cumulative effects on beluga whales and other species are 
analyzed in NMFS 2010 EA for the proposed Shell and Statoil's marine 
and seismic surveys in the Beaufort and Chukchi Seas. The take 
calculation, which takes into considerations of seasonal and spatial 
distributions of marine mammals

[[Page 49776]]

in the proposed survey areas, is provided in Statoil's IHA application 
and in the Federal Register notice for the proposed IHA (75 FR 32379; 
June 8, 2010) and in this document.
    Comment 33: Dr. Bain states that humpback whales are endangered and 
the stock inhabiting Northern Alaska has a small PBR. Due to 
uncertainty over the exact amount of human-caused mortality, it is 
unknown whether ongoing human-caused mortality exceeds potential 
biological removal (PBR). Although humpback use of the project area is 
likely to be minimal, any impact on humpbacks poses threats at both the 
individual and population level. The story is the same for fin whales, 
except that ongoing human-caused mortality is believed to be near zero 
if one does not consider ship strikes. Dr. Bain further states that the 
PBR for the Eastern Chukchi beluga stock is undetermined, because no 
recent population data are available. If PBR were estimated from old 
data, it would be 74; with an average annual subsistence harvest of 59, 
this leaves 15 individuals for other human-caused mortality, which is 
smaller than many aggregations of belugas. That is, if seismic surveys 
had lethal effects on a single group of belugas, it could put human-
caused mortality over PBR. Finally, Dr. Bain states that killer whales 
have been observed in the project area, but the stock(s) present is 
unknown. They are most likely members of the Gulf of Alaska, Aleutian 
Islands, and Bering Sea Transient Stock, which has a PBR of 3.1, some 
of which is caused by fishery interactions. A little less likely to be 
present are members of the Eastern North Pacific Alaska Resident Stock, 
which has a PBR of 11.2, with an existing human-caused mortality of 1.5 
per year. For members of either stock, lethal effects of noise to a 
single group would exceed PBR.
    Response: Regarding humpback, fin, and killer whales, their 
occurrence in the proposed project area is rare, and NMFS take 
estimates show that only 2 individuals of each of these species would 
be taken by Level B behavioral harassment as a result of the proposed 
Statoil seismic survey in the Chukchi Sea. Although a total of 184 
Eastern Chukchi Sea beluga whales are estimated to be taken by Level B 
behavioral harassment, these numbers represent less than 5 percent of 
the total Eastern Chukchi Sea beluga whales population. As mentioned in 
the Federal Register notice (75 FR 32379; June 8, 2010) and in this 
document, no takes by Level A harassment (injury) and death are 
expected or authorized for the proposed seismic activities. Therefore, 
the discussion of PBR is inapplicable to this action.
    Comment 34: AWL notes that Statoil's closely spaced survey lines 
and large cross-track distances will result in the ``repeated exposure 
of the same area of waters.'' AWL further states that although the area 
of overlap for 160-dB does not directly apply to the smaller 180- and 
190-dB safety zones, the logic employed does reveal the potential for 
non-migratory species to encounter Statoil's surveying a number of 
times over its duration, since NMFS considers repeated exposure to 
sound levels that potentially cause TTS to potentially risk causing 
PTS.
    Response: Repeated exposure may cause a marine mammal to exhibit 
diminished responsiveness (habituation), or disturbance effects may 
persist; the latter is most likely with sounds that are highly variable 
in characteristics, infrequent, and unpredictable in occurrence, and 
associated with situations that a marine mammal perceives as a threat, 
which will not be the case with Statoil's seismic survey. Additionally, 
the relatively short crosstrack distance of the 180- and 190-dB radius 
associated with Statoil's seismic survey result in small areas of 
overlap of exposed waters during the survey.
    Moreover, as explained in detail elsewhere in this document, marine 
mammals will need to be closer to the seismic source and be exposed to 
SPLs greater than 190 dB to be exposed to sound levels that could cause 
TTS. In order for a marine mammal to receive multiple exposures (and 
thereby incur PTS), the animal would: (1) Need to be close to the 
vessel and not detected during the period of multiple exposures; (2) be 
swimming in approximately the same direction and speed as the vessel; 
and (3) not be deflected away from the vessel as a result of the noise 
from the seismic array. Preliminary model simulations for seismic 
surveys in the Gulf of Mexico indicate that marine mammals are unlikely 
to incur single or multiple exposure levels that could result in PTS, 
as the seismic vessel would be moving at about 4-5 knots, while the 
marine mammals would not likely be moving within the zone of potential 
auditory injury in the same direction and speed as the vessel, 
especially for those marine mammals that take measures to avoid areas 
of seismic noise.
    Comment 35: NSB indicates that Statoil's approach to estimating 
densities of beluga and bowhead whales is problematic. The best 
available scientific data show that most marine mammals move 
considerable distances over the course of the open water period and are 
not confined to a small area. This movement occurs throughout the open 
water period and is most intense during the autumn (late August through 
November) when marine mammals are migrating south through the Chukchi 
Sea. NSB requests that NMFS use the most appropriate methods for 
estimating takes.
    AWL also questions the use of a ``density'' measure in determining 
take in the Chukchi Sea during the bowhead migration. AWL states that 
NMFS has recognized in the past that using density is inappropriate for 
determining bowhead take from seismic activities in the Beaufort Sea 
during the fall. AWL and NSB point out that Statoil used a density 
approach which assumes animals remain relatively stationary from one 
day to the next, but this assumption is inapplicable for surveying that 
will take place within a migratory corridor. AWL points out that the 
proposed IHA does not indicate the rationale for using an approach that 
ignores the fact that bowhead whales will pass through the Chukchi Sea 
in the fall. Dr. Bain notes that properly taking the bowhead migration 
into account, along with an appropriate sound threshold for harassment, 
could dramatically increase the estimate of harassed whales.
    Response: Statoil's density estimates for bowhead and beluga whales 
are based on the best scientific information available, which is the 
standard required by the MMPA implementing regulations at 50 CFR 
216.102(a). The alternative method referred to by AWL for estimating 
take of migrating bowhead whales was only used for seismic operations 
in the Beaufort Sea for Shell's site clearance and seismic surveys (75 
FR 22708; May 18, 2010). This method has not been applied to activities 
in the Chukchi Sea. Because the migration corridor is narrower and 
better defined in the Beaufort Sea than the Chukchi Sea, this method 
was deemed appropriate by NMFS for seismic operations in the Beaufort. 
However, the migratory path taken by bowhead whales once they enter the 
Chukchi Sea is not as well understood. Moreover, the migratory route is 
not as narrowly defined in the Chukchi. Additionally, if these species 
avoid areas of active seismic operations at levels lower than 160 dB re 
1 [mu]Pa (rms), as noted by several of the commenters, then fewer 
animals will occur in the area of Statoil's operations. After careful 
evaluation of the methods used by Statoil to estimate take, NMFS has 
determined that Statoil used the best

[[Page 49777]]

scientific information available in calculating the take estimates.
    Comment 36: Citing George and Suydam (1998), NSB states that killer 
whales and ribbon seals occur regularly in the Chukchi Sea and are thus 
not extralimital, as Statoil described in its IHA application. NSB 
points out that NMFS should consider ribbon seals, killer whales, and 
minke whales to occur regularly in the survey area, to be conservative.
    Response: NMFS based its population assessment on the Alaska Marine 
Mammal Stock Assessment Reports (Allen and Angliss 2010), peer-reviewed 
or other technical articles, and prior year monitoring reports of 
seismic surveys to estimate the likelihood of their occurrence and 
calculate the take numbers for the species. Although George and Suydam 
(1998) reported in their paper on killer whale predation in the 
northeastern Chukchi and western Beaufort Seas, they acknowledged that 
``[k]iller whales (Orcinus orca) are infrequently reported from the 
northeastern Chukchi and western Beaufort Seas.'' Based on the 
available information, NMFS does not expect that these species are 
likely to be taken in numbers representing more than a chance 
occurrence, as specified in the Federal Register notice for the 
proposed IHA (75 FR 32379; June 8, 2010).
    Comment 37: NSB points out that Statoil's application does not 
provide information about the movements of the Beaufort Sea stock of 
beluga whales through the Chukchi Sea, and that these beluga whales do 
migrate through the Chukchi Sea during the fall, when Statoil may be 
conducting seismic activities. NSB further points out that the minimum 
population estimate of 3,700 in NMFS' Alaska Marine Mammal Stock 
Assessment Reports (Angliss and Allen 2009) may be an underestimate of 
the actual population.
    Response: Statoil does state in the IHA application that ``[i]n the 
fall, beluga whale densities in the Chukchi Sea are expected to be 
somewhat higher than in the summer because individuals of the eastern 
Chukchi Sea stock and the Beaufort Sea stock will be migrating south to 
their wintering grounds in the Bering Sea.'' The take estimates of 
marine mammals are based on the densities of animals in particular 
areas (e.g., Moore et al. 2000), and calculated to yield the number of 
animals that are likely to be ``taken'' within modeled zones of 
influence, as described in details in Statoil's IHA application. 
Therefore, the calculation of marine mammal take estimation is relevant 
to its population size. However, stock or population size of a marine 
mammal species is used in determining whether the number of takes 
affect a ``small number'' of marine mammals. For a given level of 
``take,'' a species with a small population is expected to experience 
larger impact than a species with a larger population size. Therefore, 
contrary to what NSB states, using the minimum population estimate 
(since the best population estimate is unknown) of eastern Chukchi Sea 
beluga to calculate the percentage of take is actually a conservative 
measure to assess takes of marine mammals.

Subsistence Issues

    Comment 38: AEWC states that the nondiscretionary congressional 
directive that there will be no more than a negligible impact to marine 
mammals and no unmitigable adverse impact on the availability of marine 
mammals for subsistence taking is consistent with the MMPA's overall 
treatment of both marine mammal and subsistence protections. AEWC 
further states that Congress has set a ``moratorium on the taking * * * 
of marine mammals,'' 16 U.S.C. 1371(a), with the sole exemption 
provided for the central role of subsistence hunting by Alaska Natives. 
Thus, AEWC concludes that Congress has given priority to subsistence 
takes of marine mammals over all other exceptions to the moratorium, 
which may be applied for and obtained only if certain statutory and 
regulatory requirements are met. However, AEWC states that incidental 
harassment authorizations are available only for specified activities 
for which the Secretary makes the mandated findings. Thus, the pursuit 
of those activities is subordinated, by law, to the critical 
subsistence uses that sustain Alaska's coastal communities. AWL and NSB 
further states that NMFS has not adequately demonstrated that the 
proposed activities will not have ``an unmitigable adverse impact on 
the availability of such species or stock for taking for subsistence 
uses.''
    Response: The MMPA does not prohibit an activity from having an 
adverse impact on the availability of marine mammals for subsistence 
uses; rather, the MMPA requires NMFS to ensure the activity does not 
have an unmitigable adverse impact on the availability of such species 
or stocks for taking for subsistence uses. NMFS has defined 
``unmitigable adverse impact'' in 50 CFR 216.103 as an impact resulting 
from the specified activity: (1) That is likely to reduce the 
availability of the species to a level insufficient for a harvest to 
meet subsistence needs by: (i) Causing the marine mammals to abandon or 
avoid hunting areas; (ii) directly displacing subsistence users; or 
(iii) placing physical barriers between the marine mammals and the 
subsistence hunters; and (2) that cannot be sufficiently mitigated by 
other measures to increase the availability of marine mammals to allow 
subsistence needs to be met.
    For the determination of the unmitigable adverse impact analysis, 
NMFS, other government agencies, and affected stakeholder agencies and 
communities were provided a copy of the POC in May 2010, which outlined 
measures Statoil would implement to ensure no unmitigable adverse 
impact to subsistence uses. The POC specifies times and areas to avoid 
in order to minimize possible conflicts with traditional subsistence 
hunts by North Slope villages for transit and open-water activities. 
Statoil waited to begin activities until the close of the spring beluga 
hunt in the village of Point Lay. Statoil has also developed a 
Communication Plan and will implement the plan before initiating the 
2010 program to coordinate activities with local subsistence users as 
well as Village Whaling Associations in order to minimize the risk of 
interfering with subsistence hunting activities, and keep current as to 
the timing and status of the bowhead whale migration, as well as the 
timing and status of other subsistence hunts. The Communication Plan 
includes procedures for coordination with Communication and Call 
Centers to be located in coastal villages along the Chukchi Sea during 
Statoil's program in 2010.
    Based on the measures contained in the IHA (and described later in 
this document), NMFS has determined that mitigation measures are in 
place to ensure that Statoil's operations do not have an unmitigable 
adverse impact on the availability of marine mammal species or stocks 
for subsistence uses.
    Comment 39: AWL points out that the importance of bowhead and 
beluga whales to coastal communities and their acknowledged sensitivity 
to noise impacts strongly favor a precautionary approach, and that to 
implement such an approach, NMFS should first undertake a comprehensive 
assessment of traditional ecological knowledge.
    Response: NMFS recognizes the importance of bowhead whales and 
other marine mammals to coastal communities and thus is taking a 
precautionary approach in evaluating the potential impacts that may 
rise from Statoil's seismic surveys. NMFS has prepared an Environmental 
Assessment (EA) and Finding of No Significant Impact for the issuance 
of IHAs to Statoil and Shell to take marine

[[Page 49778]]

mammals incidental to the proposed seismic and marine surveys in the 
2010 open water season in the Beaufort and Chukchi Seas (NMFS 2010). 
The EA provides a comprehensive review of the traditional ecological 
knowledge and assessed the potential impacts to the subsistence life in 
the Arctic from the proposed survey activities.

Mitigation and Monitoring Concerns

    Comment 40: NSB and Dr. Bain are concerned that MMOs cannot see 
animals at the surface when it is dark or during the day because of 
fog, glare, rough seas, the small size of animals such as seals, and 
the large portion of time that animals spend submerged. NSB also notes 
that Statoil has acknowledged that reported sightings are only 
``minimum'' estimates of the number of animals potentially affected by 
surveying.
    Response: NMFS recognizes the limitations of visual monitoring in 
darkness and other inclement weather conditions. Therefore, in the IHA 
to Statoil, NMFS requires that no seismic airgun can be ramped up when 
the entire safety zones are not visible. However, Statoil's operations 
will occur in an area where periods of darkness do not begin until 
early September. Beginning in early September, there will be 
approximately 1-3 hours of darkness each day, with periods of darkness 
increasing by about 30 min each day. By the end of the survey period, 
there will be approximately 8 hours of darkness each day. These 
conditions provide MMOs favorable monitoring conditions for most of the 
time.
    Comment 41: NSB and AEWC note that Statoil asserts that mitigation 
measures are designed to protect animals from injurious takes, but it 
is not clear that these mitigation measures are effective in protecting 
marine mammals or subsistence hunters. AEWC states that data previously 
presented by Shell and ConocoPhillips from their seismic activities 
made clear that MMOs failed to detect many marine mammals that 
encroached within the designated safety zones. AEWC also states that 
laser rangefinding binoculars are not useful in measuring distances to 
animals directly.
    Response: NMFS believes that the required monitoring and mitigation 
measures are effective and are an adequate means of effecting the least 
practicable impact to marine mammals and their habitats. The monitoring 
reports from 2006, 2007, 2008, and 2009 do not note any instances of 
serious injury or mortality (Patterson et al. 2007; Funk et al. 2008; 
Ireland et al. 2009; Reiser et al. 2010). Additionally, the fact that a 
power-down or shutdown is required does not indicate that marine 
mammals are not being detected or that they are incurring serious 
injury. As discussed elsewhere in this document and in the Notice of 
Proposed IHA (75 FR 32379; June 8, 2010), the received level of a 
single seismic pulse (with no frequency weighting) might need to be 
approximately 186 dB re 1 [mu]Pa\2\-s (i.e., 186 dB sound exposure 
level [SEL]) in order to produce brief, mild TTS (a non-injurious, 
Level B harassment) in odontocetes. Exposure to several strong seismic 
pulses that each have received levels near 175-180 dB SEL might result 
in slight TTS in a small odontocete, assuming the TTS threshold is (to 
a first approximation) a function of the total received pulse energy. 
For Statoil's proposed survey activities, the distance at which the 
received energy level (per pulse) would be expected to be >= 175-180 dB 
SEL is the distance to the 190 dB re 1 [mu]Pa (rms) isopleth (given 
that the rms level is approximately 10-15 dB higher than the SEL value 
for the same pulse). Seismic pulses with received energy levels >= 175-
180 dB SEL (190 dB re 1 [mu]Pa (rms)) are modeled to be restricted to a 
radius of approximately 700 m around the airgun array, but are likely 
to be smaller due to the larger airgun array used in modeling.
    For baleen whales, there are no data, direct or indirect, on levels 
or properties of sound that are required to induce TTS. The frequencies 
to which baleen whales are most sensitive are lower than those to which 
odontocetes are most sensitive, and natural background noise levels at 
those low frequencies tend to be higher. As a result, auditory 
thresholds of baleen whales within their frequency band of best hearing 
are believed to be higher (less sensitive) than are those of 
odontocetes at their best frequencies (Clark and Ellison 2004). From 
this, it is suspected that received levels causing TTS onset may also 
be higher in baleen whales.
    In pinnipeds, TTS thresholds associated with exposure to brief 
pulses (single or multiple) of underwater sound have not been measured. 
Initial evidence from prolonged exposures suggested that some pinnipeds 
may incur TTS at somewhat lower received levels than do small 
odontocetes exposed for similar durations (Kastak et al. 1999; 2005). 
However, more recent indications are that TTS onset in the most 
sensitive pinniped species studied (harbor seal, which is closely 
related to the ringed seal) may occur at a similar SEL as in 
odontocetes (Kastak et al. 2004).
    NMFS concluded that cetaceans and pinnipeds should not be exposed 
to pulsed underwater noise at received levels exceeding, respectively, 
180 and 190 dB re 1 [mu]Pa (rms). The established 180- and 190-dB re 1 
[mu]Pa (rms) criteria are not considered to be the levels above which 
TTS might occur. Rather, they are the received levels above which, in 
the view of a panel of bioacoustics specialists convened by NMFS before 
TTS measurements for marine mammals started to become available, one 
could not be certain that there would be no injurious effects, auditory 
or otherwise, to marine mammals. As summarized above, data that are now 
available imply that TTS is unlikely to occur unless bow-riding 
odontocetes are exposed to airgun pulses much stronger than 180 dB re 1 
[mu]Pa rms (Southall et al. 2007). No cases of TTS are expected as a 
result of Statoil's proposed activities given the small size of the 
source, the strong likelihood that baleen whales (especially migrating 
bowheads) would avoid the approaching airguns (or vessel) before being 
exposed to levels high enough for there to be any possibility of TTS, 
and the mitigation measures proposed to be implemented during the 
survey described later in this document.
    There is no empirical evidence that exposure to pulses of airgun 
sound can cause PTS in any marine mammal, even with large arrays of 
airguns (see Southall et al. 2007). PTS might occur at a received sound 
level at least several decibels above that inducing mild TTS if the 
animal is exposed to the strong sound pulses with very rapid rise time. 
Given the higher level of sound necessary to cause PTS, it is even less 
likely that PTS could occur. In fact, even the sound levels immediately 
adjacent to the airgun may not be sufficient to induce PTS, especially 
because a mammal would not be exposed to more than one strong pulse 
unless it swam immediately alongside the airgun for a period longer 
than the inter-pulse interval. Baleen whales, and belugas as well, 
generally avoid the immediate area around operating seismic vessels. 
The planned monitoring and mitigation measures, including visual 
monitoring, power-downs, and shutdowns of the airguns when mammals are 
seen within the safety radii, will minimize the already-minimal 
probability of exposure of marine mammals to sounds strong enough to 
induce PTS.
    NMFS does not believe that MMOs failed to detect many marine 
mammals that encroached within the designated safety zones. As 
indicated in the monitoring reports for prior years' open water seismic 
surveys, marine mammals were routinely detected before and

[[Page 49779]]

during seismic surveys using airgun arrays. Although the reports reveal 
that a few marine mammals entered the designated safety zone without 
being detected immediately, these events occurred very infrequently and 
shutdowns were called for immediately when a marine mammal was found 
within the safety zone. Despite these rare occurrences, NMFS does not 
believe animals would have experienced TTS or injury because, as noted 
throughout this document, the 180 dB and 190 dB thresholds for injury 
are conservative and the best available science indicates animals need 
to be exposed to significantly higher received levels or for much 
longer duration to experience TTS, let alone injury, which was very 
unlikely in the cases documented in prior years' surveys.
    NMFS acknowledges that night-time monitoring by using night vision 
devices is not nearly as effective as visual observation during 
daylight hours. Therefore, the IHA issued to Statoil prohibits start up 
of seismic airguns when the entire safety zone cannot be effectively 
monitored during the night-time hours. Therefore, if Statoil has a 
shutdown of its seismic airgun array during low-light hours, it will 
have to wait till daylight to start ramping up the airguns.
    Comment 42: Citing the report from the peer review panel created 
for the 2010 Open Water meeting, AWL points out that the report stated 
that Statoil's ``proposed methods would not be sufficient for adequate 
monitoring of the area within the safety radii when the radii are far 
from the vessel.'' NSB also questions the ability of MMOs to detect 
marine mammals within the 2,500 m safety radii of 180-dB isopleths. AWL 
further points out that the proposed IHA needs to clarify how marine 
mammal observers on the support vessels will assist in monitoring 
safety zones, because the peer review comments noted that even with the 
addition of two support vessels, Statoil ``will be able to monitor only 
a limited area.''
    Response: First, the comment by the peer review panel in March 2010 
during the Open Water meeting in Anchorage, Alaska, was based on a 
draft version of the Statoil's IHA application, which did not include 
monitoring measures such as the use of ``Big Eye'' binoculars (25 x 
50). In working with Statoil, NMFS has required the applicant to 
include the use of ``Big Eye'' binoculars as a standard device for 
marine mammal monitoring. In addition, NMFS has also included a number 
of recommendations from the peer review panel as requirements in the 
IHA to improve marine mammal monitoring during Statoil's seismic 
survey. These recommendations, which are discussed in more detail 
below, include: (1) The use of ``big eyes'' paired with searching with 
the naked eye; (2) use of the best possible positions for observing 
(e.g., outside and as high on the vessel as possible); and (3) pairing 
experienced MMOs with MMOs who are lacking experience. Further, the 
estimated safety radii for 180-dB and 190-dB isopleths are at 2,500 m 
and 700 m from the seismic airgun source, respectively, based on 
modeling of a large airgun array (3,147 in\3\) and adjusted upward. The 
empirically measured distances from this bigger airgun array from 2006-
2009 were 460 m, 550 m, and 610 m for the 190-dB isopleths, and 1,400 
m, 2,470 m, and 2,000 m for the 180-dB isopleths. All these safety 
radii are smaller than the estimated ones for the smaller airgun array. 
Therefore, NMFS expects that the empirically measured safety radii for 
the airgun array used in Statoil's proposed seismic survey would be 
much smaller than currently modeled, which would reduce the distance to 
be monitored.
    Regarding the use of support vessels to assist in monitoring safety 
zones and zones of influence, the lead MMO on the seismic source vessel 
(or his/her designee) will work with the seismic contractor and/or the 
Captain to identify areas that will be ensonified to levels >= 160 dB 
during the next 24- to 48-hour time period. Based on this information 
MMOs on the source vessel will communicate that information to MMOs and 
the Captains of support vessels. Statoil will have two support vessels 
(Tanux I and Norseman I) assisting the seismic source vessel with this 
monitoring and other project-related activities. Monitoring routes 
within the >= 160 dB are often a series of zig-zags, or a racetrack 
pattern. The goal is to maximize monitoring coverage within the >= 160 
dB zone as dictated by support vessel availability, daylight, and 
survey conditions to ensure that aggregates of non-migratory baleen 
whales are not present within the zone. Support vessels will transit to 
and begin monitoring of these locations while maintaining routine 
communications with the source vessel MMOs to report monitoring status 
and any relevant sightings.
    Comment 43: AWL and Dr. Bain note that NMFS appears to simply 
presume that marine mammals will naturally avoid airguns when they are 
operating (even when limited to the single mitigation gun), removing 
the need for monitoring when conditions prevent observers from 
effectively watching for intrusions into the exclusion zones. AWL and 
NSB point out that the requirement for ramp ups rests on the same 
foundation--that marine mammals will leave an affected area as a result 
of increasing noise. Citing a report by the Joint Subcommittee on Ocean 
Science and Technology (JSOST 2009), AWL questions the efficacy of ramp 
up. NSB also questions the ability of power down and shutdown to 
protect marine mammals.
    Response: NMFS recognizes that uncertainties regarding marine 
mammal responses to seismic airgun noise still exist, including 
avoidance, behavioral reactions, temporary displacement, etc. However, 
there are many field studies and observations indicating that animals 
are not likely to occur within an area where sound levels could cause 
impairment to their auditory apparatus (see review by Richardson et al. 
1995; Southall et al. 2007). In addition, monitoring reports during 
prior years' seismic surveys all record more marine mammal sightings in 
the vicinity of the seismic vessel when airguns are off than when 
airguns are on (Patterson et al. 2007; Funk et al. 2008; Ireland et al. 
2009; Reiser et al. 2010).
    For the time period of Statoil's seismic surveys, daylight will 
occur for 24 h/day until mid-August. Until that date MMOs will 
automatically be observing during the 30-minute period preceding a ramp 
up. Later in the season when visibility becomes low, MMOs will be 
called out at night to observe prior to and during any ramp up using 
night vision devices (Generation 3 binocular image intensifiers, or 
equivalent units). Nevertheless, in the IHA NMFS requires that no 
airgun can be started for ramp up if the entire safety zones cannot be 
visually observed for at least 30 minutes.
    NMFS recognizes that the efficacy of ramp-up has not been well 
studied. However, before additional scientific information becomes 
available to show its lack of effectiveness in warning away marine 
mammals, the employment of ramp up will be required. To help evaluate 
the utility of ramp-up procedures, NMFS will require observers to 
record and report their observations during any ramp-up period. An 
analysis of these observations may lead to new information regarding 
the effectiveness of ramp-up and should be included in the monitoring 
report for the 2010 Statoil seismic survey.
    Nevertheless, NMFS is confident about the efficacy of power down 
and especially shutdown in protecting marine mammals from Level A and B 
harassment from seismic noise sources. By shutting down the airgun 
array, there will be no seismic noise produced, therefore, marine 
mammals are unlikely

[[Page 49780]]

be taken by Level A and B harassment from noise exposure. Similarly, by 
powering down the acoustic source, the safety zones will be reduced, 
and marine mammals that were in these zones will now be placed outside 
the zones ensonified by a smaller airgun source.
    Comment 44: The Commission recommends NMFS require the applicant to 
collect data on the behavior and movements of any marine mammals 
present during all ramp-up and power-down procedures to help evaluate 
the effectiveness of these procedures as mitigation measures; and (2) 
undertake or prompt others to undertake studies needed to resolve 
questions regarding the effectiveness of ramp-up and power-down as 
mitigation measures. NSB also questions the effectiveness of ramp-up 
measures.
    Response: In order to issue an incidental take authorization (ITA) 
under Sections 101(a)(5)(A) and (D) of the MMPA, NMFS must, where 
applicable, set forth the permissible methods of taking pursuant to 
such activity, and other means of effecting the least practicable 
impact on such species or stock and its habitat, paying particular 
attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of such species or stock for 
taking for certain subsistence uses (where relevant). For Statoil's 
proposed open water seismic surveys, a series of mitigation and 
monitoring measures are required under the IHA. These mitigation 
measures include: (1) Sound source measurements to determine safety 
zones more accurately, (2) establishment of safety and disturbance 
zones to be monitored by MMOs on the seismic vessel, (3) a power-down 
when a marine mammal is detected approaching a safety zone and a 
shutdown when a marine mammal is observed within a zone, (4) ramp-up of 
the airgun array, and (5) a requirement that vessels reduce speed when 
within 274 m (300 yards) of whales and steer around those whales if 
possible.
    The basic rationale for these mitigation measures is (a) to avoid 
exposing marine mammals to intense seismic airgun noises at received 
levels that could cause TTS (for mitigation measures listed as (1) 
through (4)); and (b) to avoid vessel strike of marine mammals 
(mitigation measure (5)). Although limited research in recent years 
shows that noise levels that could induce TTS in odontocetes and 
pinnipeds are much higher than current NMFS safety thresholds (i.e., 
180 dB and 190 dB re 1 [mu]Pa (rms) for cetaceans and pinnipeds, 
respectively), mitigation measures listed in (1) through (3) provide 
very conservative measures to ensure that no marine mammals are exposed 
to noise levels that would result in TTS. The power-down measure listed 
in (3) requires Statoil to reduce the firing airguns accordingly so 
that a marine mammal that is detected approaching the safety zone will 
be further away from the reduced safety radius (as a result of power-
down).
    Regarding mitigation measures requiring ramp-ups and power-down, 
while scientific research built around the question on whether ramp-up 
is effective has not been conducted, several studies on the effects of 
anthropogenic noise on marine mammals indicate that many marine mammals 
will move away from a sound source that they find annoying (e.g. Malme 
et al. 1984; Miller et al. 1999; others reviewed in Richardson et al. 
1995). In particular, three species of baleen whales have been the 
subject of tests involving exposure to sounds from a single airgun, 
which is equivalent to the first stage of ramp-up. All three species 
were shown to move away at the onset of a single airgun operation 
(Malme et al. 1983; 1984; 1985; 1986; Richardson et al. 1986; McCauley 
et al. 1998; 2000). From this research, it can be presumed that if a 
marine mammal finds a noise source annoying or disturbing, it will move 
away from the source prior to sustaining an injury, unless some other 
over-riding biological activity keeps the animal from vacating the 
area. This is the premise supporting NMFS' and others' belief that 
ramp-up is effective in preventing injury to marine mammals. However, 
to what degree ramp-up protects marine mammals from exposure to intense 
noises is unknown. For power-down, the rationale is that by powering 
down airgun arrays, marine mammals that are exposed to received noise 
levels that could induce TTS will be exposed to lower levels of sound 
due to the reduction in the output of the airgun source. Nevertheless, 
NMFS will require industry applicants that will conduct marine or 
seismic surveys in the 2010 open water season to collect, record, 
analyze, and report MMO observations during any ramp-up and power-down 
periods.
    Comment 45: Citing Thomas et al. (2002), Dr. Bain states that the 
effective strip half-width ([micro], the point at which the number of 
animals sighted beyond that distance equals the number missed inside) 
is the maximum distance at which the species of interest can be sighted 
(w), then the number of animals missed closer to the vessel than 
[micro] equals the number of animals sighted between [micro] and w. Dr. 
Bain further assumes that [micro] is the distance to the 180 dB contour 
(isopleths, the approximate value of [micro] in Figure 15.3 of 
Richardson and Thomas (2002) for Beaufort 0-3) and w is the distance to 
the 160 dB contour (isopleths), and points out that if one whale is 
seen in the outer zone (radius of 13 km for the 160-dB isopleths) 
``where the sighting probability is say 9% or less,'' that would 
suggest that one whale was missed in the inner zone (radius of 2.5 km 
for the 180-dB isopleths), and 10 were missed in the outer zone. Dr. 
Bain concludes that ``the sighting of a single whale outside the strip 
half-width would be strong evidence that 12 are present.'' Dr. Bain 
thus summarizes that ``if a whale is sighted in the inner zone, the 
airguns would shut down per the 180 dB rule. If a whale is sighted in 
the outer zone, that would imply that 12 are present within the 160 dB 
contour, and hence the airguns should shut down per the 160 dB rule. 
That is, sighting a single bowhead or gray whale, regardless of 
distance, is evidence the shutdown criteria have been met.'' Dr. Bain 
further states that even if no whales are seen, the shutdown criteria 
may have been meet, as he states that from high observation platforms 
(11-27 m in eye height), a pair of observers has about a 60% chance of 
detecting a mysticete whale at the 180-dB isopleths (2.5 km), and that 
for the paired observation team plots, where sample size is larger, the 
observers are estimated to have about a 50% chance of seeing a whale at 
2.5 km. That is, Dr. Bain concludes, ``a whale can be in the zone where 
there is a risk of immediate injury or death and have only a 50% chance 
of triggering a shutdown under ideal conditions.'' Dr. Bain then 
applies the same logic for seals and states that ``a high proportion of 
seals within the 190 dB contour will fail to trigger a shutdown.''
    Response: While NMFS agrees with Dr. Bain's assessment in 
principle, NMFS disagrees with a number of assumptions being made in 
his comments. First, the reference Dr. Bain used to extrapolate the 
effective strip half-width ([micro] = 2.5 km) and sighting probability 
(9%) addresses correction factors that were used for aerial surveys. 
Although aerial surveys are conducted at higher platforms than vessel 
surveys, the speed of an aircraft (approximately 100 knots) does not 
allow adequate time for scanning a particular area, and thus may miss 
marine mammals if they happen to be underwater. Therefore, using an 
aerial sighting probability of 9% to address vessel surveys may not be 
appropriate. Second, Dr. Bain's

[[Page 49781]]

hypothetical 9% sighting probability is based on the assumption of 
using one survey platform only. For Statoil's proposed seismic survey, 
multiple vessels besides the source vessel will be employed for marine 
mammal monitoring, and these chase/monitoring vessels are able to fill 
the sighting gaps that MMOs from the source vessel may miss. Third, 
using sighting probability for the entire survey tracklines may not be 
a realistic way to predict the number of animals in the vicinity of the 
survey area, which tends to be moving constantly. Unless the animals 
congregate in a large group, sighting probability at an instantaneous 
location should be interpreted as the percentage of probability of 
detecting a single animal, instead of the percentage of a group of 
animals in the area. Therefore, it does not seem reasonable to call for 
a shutdown of seismic airguns when a whale is detected in the 160-dB 
zone of influence.
    Regarding Dr. Bain's second comment that a whale has a 50% chance 
of facing the risk of immediate injury or death when occurring at a 
distance of 2.5 km is scientifically baseless. First, even if the whale 
or seals were not spotted by the MMOs at 2.5 km or 700 m, respectively, 
from the seismic vessel, the modeled received levels at these distances 
are expected to be approximately 180 dB and 190 re 1 [micro]Pa (rms), 
respectively, which are the borderline of the safety zone within which 
repeated exposure to noise received levels above 180 dB or 190 dB re 1 
[micro]Pa (rms) could induce TTS. TTS is not considered an injury in 
cetaceans or pinnipeds. As discussed in detail in the proposed IHA (75 
FR 32379; June 8, 2010) and in this document below, new scientific 
information shows that the onset of TTS is likely at much higher 
received levels. Second, as the whales are closing in, the sighting 
probability increases exponentially with reduced distance, reaching to 
over 80% at a distance of 600 m based on Figure 5.3 of Richardson and 
Thomas (2002). At this distance, the received levels are expected to be 
under 200 dB re 1 [micro]Pa (rms), which is still lower than the levels 
that are thought to induce TTS (Finneran et al. 2002; Southall et al. 
2007). Third, as the seismic survey is ongoing, NMFS considers it's 
unlikely that a marine mammal would be approaching a noise received 
level that could be uncomfortable to the animal or cause TTS. 
Therefore, Dr. Bain's conclusion that a whale will face 50% chance of 
immediate injury or death at 2,500 m away from the seismic survey 
vessel is scientifically not supported.
    Comment 46: Dr. Bain states that since animals over the horizon 
would be affected, visual detection from the seismic vessel alone would 
be inadequate to prevent exposure. It would be advisable to deploy 
trained observers on all vessels, not only the one operating airguns, 
which would allow sighting of some marine mammals that are close enough 
to be affected by noise, but too far away to be seen from source-based 
observers.
    Response: As stated in Statoil's IHA application, five observers 
will be based aboard the seismic source vessel and at least three MMOs 
on the chase/monitoring vessels. The IHA issued to Statoil requires 
that MMOs be stationed onboard both source vessels and chase/monitoring 
vessels (see Monitoring Measures section below).
    Comment 47: Dr. Bain states that short ramp-up periods do not allow 
individuals to move out to the contour at which behavioral effects no 
longer pose risks of immediate injury prior to onset of full power 
operation. He concludes that many marine mammals would at least need to 
reach the 135 dB contour to be safe from behaviorally mediated injury, 
and that for the airgun array used in this survey, that is likely to be 
over 40 km away. Dr. Bain further concludes that at normal sustained 
swimming speeds of 3-4 knots, that is likely to be at least 5-6 hours 
away.
    Response: First, claiming that marine mammals exposed to received 
levels at 135 dB are not safe from immediate injury is not 
scientifically supported, and many studies have shown that on many 
occasions animals being exposed to this level of noise have not 
exhibited any behavioral reactions, much less a reaction that would 
equate to ``take'' under the MMPA (see reviews by Richardson et al. 
1995; Southall et al. 2007).
    Second, it is important to understand that no airgun will be ramped 
up when a marine mammal is detected within the safety zones (180 dB for 
cetaceans and 190 dB for pinnipeds) by MMOs on source vessel and chase/
monitoring vessels, as stated in the IHA. This means, theoretically, 
Statoil's seismic vessel cannot even start up the 60 in \3\ mitigation 
airgun when cetaceans or pinnipeds are detected within the 2,500 m or 
700 m radii, respectively. As the operators start ramping up with the 
mitigation gun, as stated in the Federal Register notice for the 
proposed IHA (75 FR 32379; June 8, 2010) and in the Statoil's IHA 
application, the initial safety zones incurred by the mitigation gun 
are 220 m and 75 m for 180 dB and 190 dB, respectively.
    Third, even if there are marine mammals being missed during the 
initial 30 minutes pre-survey monitoring, the ramping up of the 
mitigation gun to full-power airgun array would make the safety radii 
from 220 m to 2,500 m for the 180-dB isopleths and from 75 m to 700 m 
for the 190-dB isopleths reachable within approximately 15-20 minutes. 
Using simple math, if a marine mammal is swimming at normal sustained 
speed of 4 knots (7.41 km/h), the animal would reach the border of the 
180-dB isopleths in 20 minutes (it would take pinnipeds 11 minutes to 
reach the 190-dB isopleths from the dead center of the airgun source, 
assuming a swimming speed of 3 knots (5.56 km/h)).
    Finally, anytime during the ramp up period when a marine mammal is 
detected within its respective safety zone, the airguns must be 
immediately stopped, and ramp up will be delayed until the animal is 
sighted outside of the safety zone or the animal is not sighted for at 
least 15-30 minutes (15 minutes for small odontocetes and pinnipeds, or 
30 minutes for baleen whales and large odontocetes).
    Comment 48: The Commission, NSB, and Dr. Bain recommend that 
Statoil be required to supplement its mitigation measures by using 
passive acoustic monitoring (PAM) to provide a more reliable estimate 
of the number of marine mammals taken during the course of the proposed 
seismic survey.
    Response: NMFS' 2010 EA for this action contains an analysis of why 
PAM is not required to be used by Statoil to implement mitigation 
measures. Statoil, Shell, and ConocoPhillips (CPAI) are jointly funding 
an extensive science program to continue the acoustic monitoring of the 
Chukchi Sea environment. However, this information will not be used in 
a real-time or near-real-time capacity. Along with the fact that marine 
mammals may not always vocalize while near the PAM device, another 
impediment is that flow noise generated by a towed PAM will interfere 
with low frequency whale calls and make their detection difficult and 
unreliable. MMS sponsored a workshop on the means of acoustic detection 
of marine mammals in November 2009 in Boston, MA. The workshop reviewed 
various available acoustic monitoring technology (passive and active), 
its feasibility and applicability for use in MMS-authorized activities, 
and what additional developments need to take place to improve its 
effectiveness. The conclusion is that at this stage, using towed 
passive acoustics to detect marine mammals is not a mature technology. 
NMFS may consider

[[Page 49782]]

requirements for PAM in the future depending on information received as 
the technology develops further.
    Comment 49: AWL states that additional mitigation measures are 
needed to address vulnerable cow/calf pairs. AWL recommends that NMFS 
require a safety zone that is triggered by the presence of cow/calf 
pairs because females with calves are considered to be more susceptible 
to noise disturbances, and NMFS must at least evaluate the necessity of 
additional mitigation to protect this vulnerable segment of the 
population, citing MMS' Lease Sale 193 EIS that female baleen whales 
with calves ``show a heightened response to noise and disturbance.''
    Response: Although it has been suggested that female baleen whales 
with calves ``show a heightened response to noise and disturbance,'' 
there is no evidence that such ``heightened response'' is biologically 
significant and constitutes a ``take'' under the MMPA. Nevertheless, 
NMFS requires a 120-dB safety zone for migrating bowhead cow/calf pairs 
to be implemented to reduce impacts to the animals as they migrate 
through the narrow corridor in the Beaufort Sea (see Federal Register 
notice for proposed IHA to Shell; 75 FR 22708; May 18, 2010). However, 
in the Chukchi Sea, the migratory corridor for bowhead whales is wider 
and more open, thus the 120-dB ensonified zone would not impede bowhead 
whale migration. The animals would be able to swim around the 
ensonified area. Additionally, NMFS has not imposed a requirement to 
conduct aerial monitoring of the 120-dB safety zone for the occurrence 
of four or more cow-calf pairs in the Chukchi Sea because it is not 
practicable. First, NMFS determined that monitoring the 120-dB safety 
zone was not necessary in the Chukchi Sea because there would not be 
the level of effort by 3D seismic survey operations present in 2006. 
This provides cow/calf pairs with sufficient ability to move around the 
seismic source without significant effort. Second, aerial surveys are 
not required in the Chukchi Sea because they have currently been 
determined to be impracticable due to lack of adequate landing 
facilities, and the prevalence of fog and other inclement weather in 
that area. This could potentially result in an inability to return to 
the airport of origin, thereby resulting in safety concerns.
    Comment 50: AWL states that NMFS should consider time and space 
limitations on surveying in order to reduce harm, and to restrict 
surveys to times in which the safety zones are visible to marine 
monitors. AWL requests that Statoil not operate in conditions--such as 
darkness, fog, or rough seas--in which the observers are unable to 
ensure that the safety zones are free of marine mammals. In addition, 
AWL requests NMFS to evaluate the benefits that would come from halting 
the surveying during the peak of the bowhead migration through the 
Chukchi Sea.
    Response: In making its negligible determination for the issuance 
of an IHA to Statoil for open water marine surveys, NMFS has conducted 
a thorough review and analysis on how to reduce any adverse effects to 
marine mammals from the proposed action, including the consideration of 
time and space limitations that could reduce impacts to the bowhead 
migration. As indicated in its IHA application, Statoil will complete 
its seismic survey in the first half of October to avoid the peak of 
the bowhead whale migration through the Chukchi Sea, which typically 
occurs after October. By restricting survey activities to only daylight 
hours, Statoil will not be able to complete its seismic surveys before 
its preferred date, and therefore, there could be more adverse impacts 
to migrating bowhead whales.
    Bowhead whales migrating west across the Alaskan Beaufort Sea in 
autumn, in particular are unusually responsive to airgun noises, with 
avoidance occurring out to distances of 20--30 km from a medium-sized 
airgun source (Miller et al. 1999; Richardson et al. 1999). However, 
while bowheads may avoid an area of 20 km (12.4 mi) around a noise 
source, when that determination requires a post-survey computer 
analysis to find that bowheads have made a 1 or 2 degree course change, 
NMFS believes that does not equate to ``take'' under the MMPA, and that 
such minor behavioral modification is not likely to be biologically 
significant.
    Comment 51: NSB requests NMFS to require Statoil to fly aerial 
surveys in support of its proposed activities.
    Response: Aerial monitoring is not required in IHAs for surveys 
that occur in the offshore environment of the Chukchi Sea because they 
have currently been determined to be impracticable due to lack of 
adequate landing facilities, and the prevalence of fog and other 
inclement weather in that area. This could potentially result in an 
inability to return to the airport of origin, thereby resulting in 
safety concerns.
    Comment 52: The Commission recommends that NMFS (1) revise its 
study design to include expanded pre- and post-seismic survey 
assessments sufficient to obtain reliable sighting data for comparing 
marine mammal abundance, distribution, and behavior under various 
conditions; (2) review the proposed monitoring measures and require the 
applicant (or its contractors) to collect and analyze information 
regarding all of the potentially important sources of sound and the 
complex sound field created by all of the activities associated with 
conducting the seismic survey; (3) require the applicant to collect 
information to evaluate the assumption that 160 dB is the appropriate 
threshold at which harassment occurs for all marine mammals that occur 
in the survey area; and (4) determine, in consultation with Statoil, 
whether aerial surveys are safe to conduct and should be required and, 
if not, identify alternative monitoring strategies capable of providing 
reliable information on the presence of marine mammals and the impact 
of survey activities to the affected species and stocks.
    Response: NMFS largely agrees with the Commission's recommendations 
and has been working with the seismic survey applicants and their 
contractors on gathering information on acoustic sources, survey design 
review, and monitoring analyses. NMFS has contacted Statoil and 
received information on all the active acoustic sources that would be 
used for its proposed open water marine surveys. The information 
includes source characteristics such as frequency ranges and source 
levels, as well as estimated propagation loss.
    However, due to the strict time limits for the entire seismic 
program (60 days of seismic surveys), NMFS does not consider it 
appropriate to revise its study design to include expanded pre- and 
post-seismic survey assessments to obtain sighting data for comparing 
marine mammal abundance, distribution, and behavior under various 
conditions. Such studies would require scientists with expertise in 
marine mammal distribution, population ecology, and behavioral ecology 
onboard the research vessel for extended period of time. NMFS thinks 
that such a requirement is outside the scope of the proposed action. 
Nevertheless, marine mammal sighting data and behavioral reactions 
prior to and immediately after seismic operations will be collected, as 
described in the proposed IHA (75 FR 32379; June 8, 2010) and in 
Statoil's IHA application. This information will be used to interpret 
marine mammal behavioral reactions when exposed to various received 
noise levels (except levels about 180 dB and 190 dB re 1 [mu]Pa for 
cetaceans and pinnipeds,

[[Page 49783]]

respectively) and abundance in relation to seismic surveys, which can 
be used to evaluate whether 160 dB received level is the appropriate 
threshold at which harassment occurs for all marine mammals that occur 
in the survey area.
    As far as aerial surveys are concerned, they are not required in 
the Chukchi Sea because they have currently been determined to be 
impracticable due to lack of adequate landing facilities, and the 
prevalence of fog and other inclement weather in that area. This could 
potentially result in an inability to return to the airport of origin, 
thereby resulting in safety concerns. However, Statoil is required to 
use two support vessels to monitor marine mammals in the zones of 
influence. Nevertheless, NMFS will continue working with the oil and 
gas industry in discussing the possibility of aerial surveys in the 
future.
    Comment 53: The Commission recommends that the IHA require Statoil 
to halt its seismic survey and consult with NMFS regarding any 
seriously injured or dead marine mammal when the injury or death may 
have resulted from Statoil's activities. NSB recommends Statoil be 
required to facilitate the recovery and necropsy of any marine mammals 
found dead in their survey area.
    Response: NMFS concurs with the Commission's recommendation. NMFS 
has included a condition in the IHA which requires Statoil to 
immediately shutdown the seismic airguns if a dead or injured marine 
mammal has been sighted within an area where the seismic airguns were 
operating within the past 24 hours so that information regarding the 
animal can be collected and reported to NMFS, and there is clear 
evidence that the injury or death resulted from Statoil's activities. 
In addition, Statoil must immediately report the events to the Marine 
Mammal Stranding Network within 24 hours of the sighting (telephone: 1-
800-853-1964), as well as to the NMFS staff person designated by the 
Director, Office of Protected Resources, or to the staff person 
designated by the Alaska Regional Administrator. The lead MMO is 
required to complete a written certification, which must include the 
following information: species or description of the animal(s); the 
condition of the animal(s) (including carcass condition if the animal 
is dead); location and time of first discovery; observed behaviors (if 
alive); and photographs or video (if available). In the event that the 
marine mammal injury or death was determined to have been a direct 
result of Statoil's activities, then operations will cease, NMFS and 
the Stranding Network will be notified immediately, and operations will 
not be permitted to resume until NMFS has had an opportunity to review 
the written certification and any accompanying documentation, make 
determinations as to whether modifications to the activities are 
appropriate and necessary, and has notified Statoil that activities may 
be resumed.
    For any other sighting of injured or dead marine mammals in the 
vicinity of any marine survey activities utilizing underwater active 
acoustic sources for which the cause of injury or mortality cannot be 
immediately determined, Statoil will ensure that NMFS (regional 
stranding coordinator) is notified immediately. Statoil will provide 
NMFS with species or description of the animal(s), the condition of the 
animal(s) (including carcass condition if the animal is dead), 
location, time of first discovery, observed behaviors (if alive), and 
photo or video.
    If NMFS determines that further investigation is appropriate, once 
investigations are completed and determinations made, NMFS would use 
available information to help reduce the likelihood that a similar 
event would happen in the future and move forward with necessary steps 
to ensure environmental compliance for oil and gas related activities 
under the MMPA.
    Since the cause of marine mammal deaths often cannot be determined 
immediately, and in many cases the deaths are results of gunshots or 
other trauma unrelated to Statoil's seismic surveys, NMFS does not 
believe it reasonable and practicable to require Statoil to facilitate 
the recovery and necropsy of any marine mammals found dead in their 
survey area.

Cumulative Impact Concerns

    Comment 54: NSB, AEWC, and AWL state that NMFS must also consider 
the effects of disturbances in the context of other activities 
occurring in the Arctic. NSB states that NMFS should ascertain the 
significance of multiple exposures to underwater noise, ocean 
discharge, air pollution, and vessel traffic--all of which could impact 
bowhead whales and decrease survival rates or reproductive success. NSB 
notes that the cumulative impacts of all industrial activities must be 
factored into any negligible impact determination. NSB, AEWC, and AWL 
list a series of reasonably foreseeable activities in the Arctic Ocean 
as: (1) GX Technology's Beaufort Sea seismic surveys; (2) Shell's 
Beaufort and Chukchi Seas marine surveys; (3) Seismic surveys planned 
in the Canadian Arctic; (4) U.S. Geological Survey's (USGS') seismic 
surveys; (5) BP's production operations at Northstar; and (6) 
Dalmorneftegeophysica (DMNG) Russian Far East offshore seismic surveys.
    Response: Under section 101(a)(5)(D) of the MMPA, NMFS is required 
to determine whether the taking by the applicant's specified activity 
will take only small numbers of marine mammals, will have a negligible 
impact on the affected marine mammal species or population stocks, and 
will not have an unmitigable impact on the availability of affected 
species or stocks for subsistence uses. Cumulative impact assessments 
are NMFS' responsibility under the National Environmental Policy Act 
(NEPA), not the MMPA. In that regard, MMS' 2006 Final PEA, NMFS' 2007 
and 2008 Supplemental EAs, NMFS' 2009 EA, and NMFS' 2010 EA address 
cumulative impacts. The most recent NMFS' 2010 EA addresses cumulative 
activities and the cumulative impact analysis focused on oil and gas 
related and non-oil and gas related activities in both Federal and 
State of Alaska waters that were likely and foreseeable. The oil and 
gas related activities in the U.S. Arctic in 2010 include this 
activity; Shell's proposed marine surveys in the Beaufort and Chukchi 
Seas; ION Geophysical's proposed seismic survey in Beaufort Sea; and 
BP's production operations at Northstar. GX Technology's Beaufort Sea 
seismic surveys have been cancelled by the company. Seismic survey 
activities in the Canadian and Russian Arctic occur in different 
geophysical areas, therefore, they are not analyzed under the NMFS 2010 
EA. Other appropriate factors, such as Arctic warming, military 
activities, and noise contributions from community and commercial 
activities were also considered in NMFS' 2010 EA. Please refer to that 
document for further discussion of cumulative impacts.
    Comment 55: Dr. Bain notes that in Southall et al. (2007), a 
severity scale was developed to allow a graded description of 
behavioral changes rather than forcing a binary decision about whether 
a particular change constitutes a take. Dr. Bain states that changes 
low on the scale would only have population-scale effects if the 
changes were long lasting due to long-term exposure, or were widespread 
due to sources affecting a large percentage of populations. That is, 
the population consequences of a single vessel passing by a dolphin 
would be expected to be less than a fleet of vessels spending many 
hours per day for months every year dolphin watching, even if 
behavioral responses were the same to

[[Page 49784]]

each vessel approach (Lusseau et al. 2006). Changes high on the scale 
could result in immediate injury or death through mechanisms such as 
stranding, gas bubble formation, separation of mothers from calves, 
stampedes, etc., if they occurred in the relevant setting (Southall et 
al. 2007)
    Response: Comment noted. As Dr. Bain has noted, long-term exposure 
to low level noise could have chronic, population level impacts to 
marine mammals in their environment greater than similar exposures that 
are short-term and infrequent, even though the instantaneous behavioral 
reactions are scored the same. NMFS agrees with the example that whales 
and dolphins being approached by whale watching vessels operating on a 
daily basis for many hours over a period of years are likely to suffer 
far more population consequences than, for example, marine mammals 
exposed to infrequent and short term sounds from seismic and supporting 
vessels that only operate in an area for two months. In addition to the 
received noise levels being considered, seismic vessels are required to 
implement mitigation and monitoring conditions to ensure a certain 
distance from marine mammals, while whale watching vessels usually do 
not. This is an important difference, as vessels associated with 
Statoil's seismic survey will not actually approach marine mammals. As 
analyzed in detail in the Federal Register notice (75 FR 32379; June 8, 
2010) and in this document, the proposed Statoil seismic survey in the 
Chukchi Sea would only affect a limited area over approximately 60 
days.

ESA Concerns

    Comment 56: AWL states that NMFS section 7 consultation under the 
ESA must consider the potential impact of potential future oil and gas 
activities. AWL further states that a biological opinion must detail 
how the agency action under review affects the species or its critical 
habitat. The effects of the action are then added to the 
``environmental baseline,'' which consists of the past and present 
impacts of activities in the action area as well as ``the anticipated 
impacts of all proposed Federal projects of activities in the action 
area'' as well as ``the anticipated impacts of all proposed Federal 
projects in the action area that have already undergone formal or early 
section 7 consultation.'' AWL states that NMFS must consider the 
effects of the entire agency action.
    Response: Under section 7 of the ESA, NMFS Office of Protected 
Resources has completed consultation with NMFS Alaska Regional Office 
on ``Authorization of Small Takes under the Marine Mammal Protection 
Act for Certain Oil and Gas Exploration Activities in the U.S. Beaufort 
and Chukchi Seas, Alaska for 2010.'' In a Biological Opinion issued on 
July 13, 2010, NMFS concluded that the issuance of the incidental take 
authorizations under the MMPA for seismic surveys are not likely to 
jeopardize the continued existence of the endangered humpback or 
bowhead whale. As no critical habitat has been designated for these 
species, none will be affected. The 2010 Biological Opinion takes into 
consideration all oil and gas related seismic survey activities that 
would occur in the 2010 open water season. This Biological Opinion does 
not include impacts from exploratory drilling and production 
activities, which are subject to a separate consultation. In addition, 
potential future impacts from oil and gas activities will be subject to 
consultation in the future when activities are proposed. NMFS has 
reviewed Statoil's proposed action and has determined that the findings 
in the 2010 Biological Opinion apply to its 2010 Chukchi Sea seismic 
survey. In addition, NMFS has issued an Incidental Take Statement (ITS) 
under this Biological Opinion for Statoil's survey activities, which 
contains reasonable and prudent measures with implementing terms and 
conditions to minimize the effects of take of bowhead and humpback 
whales.
    Comment 57: AWL argues that NMFS' existing regional biological 
opinion is inadequate. AWL states that NMFS' 2008 Biological Opinion 
does not adequately consider site-specific information related to 
Shell's proposed drilling. AWL points out that Shell has proposed 
exploration drilling in Camden Bay in the Beaufort Sea, and that Camden 
Bay has been repeatedly identified as a resting and feeding area for 
migrating bowheads, which has been reaffirmed by the recent monitoring. 
AWL states that NMFS should re-examine the potential impacts of Shell's 
proposed drilling in light of its long-standing policy and the 
cautionary language contained in its 2008 opinion.
    Response: NMFS initiated a section 7 consultation under the ESA for 
the potential impacts to ESA-listed marine mammal species that could be 
adversely affected as a result of several oil and gas related 
activities in the 2010 open-water season. The 2010 Biological Opinion 
covered the activities by Shell and Statoil's proposed open water 
marine and seismic survey activities. However, as far as Shell's 
drilling activities are concerned, Shell has withdrawn these actions 
due to the moratorium on offshore drilling.
    Comment 58: Dr. Bain states that bowheads are endangered, and many 
threats unrelated to oil have limited recovery of other bowhead 
population, so need to be considered.
    Response: In issuing the IHA to Statoil for the proposed marine 
seismic survey, NMFS has thoroughly considered all potential impacts to 
marine mammals, including bowhead, gray, and beluga whales and harbor 
porpoises in the project vicinity. A detailed discussion of the 
cumulative effects on these species and the Arctic environment as a 
whole is provided in NMFS 2010 EA for the issuance of IHAs to Shell and 
Statoil.
    Specific to the ESA-listed bowhead whales, as well as humpback and 
fin whales, NMFS Office of Protected Resources has conducted a 
consultation with NMFS Alaska Regional Office (AKRO) under section 7 of 
the ESA. After reviewing the current status of the fin, humpback, and 
bowhead whale, the environmental baseline for the action area, the 
biological and physical impacts of these actions, and cumulative 
effects, and considering that the described actions are expected to 
impact only a single stock of each of these endangered whales, and not 
the species as a whole, NMFS AKRO issued a Biological Opinion on July 
13, 2010. The Biological Opinion concludes that the proposed marine and 
seismic surveys by Shell and Statoil in the Beaufort and Chukchi Seas 
during the 2010 open water season are not likely to jeopardize the 
continued existence of the endangered fin, humpback, or bowhead whale. 
No critical habitat has been designated for these species, therefore 
none will be affected. In addition, the population of the Bering-
Chukchi-Beaufort Sea stock of bowhead whales is increasing at a rate of 
3.5% (Brandon and Wade 2004) or 3.4% (George et al. 2004), despite 
whales being harvested by the Alaska natives (Angliss and Allen 2009). 
The count of 121 calves during the 2001 census was the highest yet 
recorded and was likely caused by a combination of variable recruitment 
and the large population size (George et al. 2004). The calf count 
provides corroborating evidence for a healthy and increasing population 
(Angliss and Allen 2009).
    Comment 59: AWL argues that NMFS' 2008 Biological Opinion does not 
adequately consider oil spills. AWL states that in the 2008 Biological 
Opinion, NMFS recognized the potential dangers of a large oil spill, 
and that whales contacting oil, particularly freshly-spilled oil, 
``could be harmed

[[Page 49785]]

and possibly killed.'' Citing NMFS's finding in its 2008 Biological 
Opinion that several ``coincidental events'' would have to take place 
for such harm to occur: (1) A spill; (2) that coincides with the 
whales' seasonal presence; (3) that is ``transported to the area the 
whales occupy (e.g., the migrational corridor or spring lead system)''; 
and (4) is not successfully cleaned up, AWL points out that this 
combination of events is not as remote as NMFS appears to have assumed 
because NMFS' analysis of whether a spill may occur relies in part on 
statistical probabilities based on past incidents. AWL states that 
there appears to have been a significant breakdown in the system that 
was intended to both prevent spills from occurring and require adequate 
oil spill response capabilities to limit the harm. AWL states that NMFS 
must take into account that there are likely gaps in the current 
regulatory regime, and that given those flaws, an analysis that relies 
on the safety record of previous drilling is doubtful as a predictive 
tool.
    Response: As discussed in the previous Response to Comment, no 
drilling is planned for Shell during the 2010 open water season, 
therefore, these activities will be considered in a separate 
consultation if and when Statoil proposes to conduct exploratory 
drilling.

NEPA Concerns

    Comment 60: AEWC believes that NMFS excluded the public from the 
NEPA process since NMFS did not release a draft EA for the public to 
review and provide comments prior to NMFS taking its final action.
    Response: Neither NEPA nor the Council on Environmental Quality's 
(CEQ) regulations explicitly require circulation of a draft EA for 
public comment prior to finalizing the EA. The Federal courts have 
upheld this conclusion, and in one recent case, the Ninth Circuit 
squarely addressed the question of public involvement in the 
development of an EA. In Bering Strait Citizens for Responsible 
Resource Development v. U.S. Army Corps of Engineers (524 F.3d 938, 9th 
Cir. 2008), the court held that the circulation of a draft EA is not 
required in every case; rather, Federal agencies should strive to 
involve the public in the decision-making process by providing as much 
environmental information as is practicable prior to completion of the 
EA so that the public has a sufficient opportunity to weigh in on 
issues pertinent to the agency's decision-making process. In the case 
of Statoil's 2010 MMPA IHA request, NMFS involved the public in the 
decision-making process by distributing Statoil's IHA application and 
addenda for a 30-day notice and comment period. However, at that time, 
a draft EA was not available to provide to the public for comment. The 
IHA application and NMFS' Notice of Proposed IHA (75 FR 32379; June 8, 
2010) contained information relating to the project. For example, the 
application included a project description, its location, environmental 
matters such as species and habitat to be affected, and measures 
designed to minimize adverse impacts to the environment and the 
availability of affected species or stocks for subsistence uses.
    Comment 61: AEWC notes that Statoil's IHA application warrants 
review in an environmental impact statement (EIS) given the potential 
for significant impacts.
    Response: NMFS' 2010 EA was prepared to evaluate whether 
significant environmental impacts may result from the issuance of an 
IHA to Statoil, which is an appropriate application of NEPA. After 
completing the EA, NMFS determined that there would not be significant 
impacts to the human environment and accordingly issued a FONSI. 
Therefore, an EIS is not needed for this action.
    Comment 62: AEWC, AWL, and NSB note that NMFS is preparing a 
Programmatic EIS (PEIS). Although MMS published a draft PEIS (PEIS; MMS 
2007) in the summer of 2007, to date, a Final PEIS has not been 
completed. AWL also notes that NMFS and MMS have reaffirmed their 
previous determination that a programmatic EIS process is necessary to 
address the overall, cumulative impacts of increased oil and gas 
activity in the Arctic Ocean and intend to incorporate into that 
analysis new scientific information as well as new information about 
projected seismic and exploratory drilling activity in both seas. 
However, AWL and AEWC argue that NEPA regulations make clear that NMFS 
should not proceed with authorizations for individual projects like 
Statoil's surveying until its programmatic EIS is complete.
    Response: While the Final PEIS will analyze the affected 
environment and environmental consequences from seismic surveys in the 
Arctic, the analysis contained in the Final PEIS will apply more 
broadly to Arctic oil and gas operations. NMFS' issuance of an IHA to 
Staoil for the taking of several species of marine mammals incidental 
to conducting its open-water seismic survey program in the Chukchi Sea 
in 2010, as analyzed in the EA, is not expected to significantly affect 
the quality of the human environment. Statoil's surveys are not 
expected to significantly affect the quality of the human environment 
because of the limited duration and scope of Statoil's operations. 
Additionally, the EA contained a full analysis of cumulative impacts.

Miscellaneous Issues

    Comment 63: The AEWC states that Statoil has refused to sign the 
2010 Open Water Season Conflict Avoidance Agreement (CAA), despite very 
significant concessions by the AEWC. AEWC believes the greatest concern 
here is the fact that NMFS must find, on behalf of the Secretary, that 
Statoil's proposed operations will not have an unmitigable adverse 
impact on the availability of marine mammals for subsistence uses. AEWC 
claims that in the absence of a CAA, NMFS has no independent basis on 
which to make this finding.
    Response: Under sections 101(a)(5)(A) and (D) of the MMPA (16 
U.S.C. 1361 et seq.), an IHA or LOA shall be granted to U.S. citizens 
who engage in a specified activity (other than commercial fishing) 
within a specified geographical region if NMFS finds that the taking of 
marine mammals 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. In 
other words, no marine mammal take authorizations may be issued if NMFS 
has reason to believe that the proposed exploration or development 
activities would have an unmitigable adverse impact on the availability 
of marine mammal species or stock(s) for Alaskan native subsistence 
uses. For the proposed marine surveys, Statoil has conducted Plan of 
Cooperation (POC) meetings for its seismic operations in the Chukchi 
Sea in the communities and villages of Barrow, Wainwright, Point Lay, 
and Point Hope, and met with representatives of the Marine Mammal Co-
Management groups, including the AEWC, Ice Seal Commission, Alaska 
Beluga Whale Committee, Alaska Eskimo Walrus Commission, and the Nanuq 
Commission, on March 22, 2010. At each of these meetings, Statoil 
described the proposed survey program and measures it plans to take, or 
has taken, to minimize adverse effects its proposed seismic survey may 
have on the

[[Page 49786]]

availability of marine mammals for subsistence use. Statoil requested 
comments and feedback from subsistence users, and incorporated those 
comments and concerns in the final version of the POC, which was 
released on May 28, 2010. The final POC document contains the following 
information: (1) A description of the proposed marine seismic survey; 
(2) documentation of consultation with local communities and tribal 
governments; (3) a description of mitigation measures to reduce the 
impact of Statoil's planned activity on subsistence; (4) ongoing 
Chukchi Sea scientific research which Statoil is conducting to gather 
information on the marine environment; and (5) the future plans for 
meetings and communication with the affected subsistence Chukchi Sea 
communities.
    In addition, Statoil has entered into a Communication Protocol 
through a Participation Agreement with Shell to fund and staff a 
communications station out of Wainwright. The communications center 
will be staffed by Inupiat operators and on a 24/7 basis during the 
2010 subsistence bowhead whale hunt. Call center staff will receive 
notifications from vessels at least once every six hours and will plot 
the probable location of vessels on a map at the communications center. 
Communications center staff will apprise vessel operators of potential 
operations that may conflict with subsistence whaling activities.
    The measures that Statoil has taken, and will take, under the POC, 
Marine Mammal Monitoring and Mitigation Plan (4MP), and the 
Participation Agreement are similar to the measures identified in the 
draft Conflict Avoidance Agreement provided by AEWC. Below, Statoil and 
NMFS identify the key conflict-avoidance provisions of the CAA, and 
identify the corresponding provisions of the POC, 4MP, and the 
Participation Agreement focused on minimizing impacts to the 
environment and subsistence resources in the Chukchi Sea.
(1) Post-Seasons Review/Preseason Introduction
    Under section 108 of the CAA, following the completion of the 2010 
Chukchi Sea Open Water Season, and prior to the start of the 2011 
season, the AEWC or Whaling Captain's Association of each village may 
request meetings with Industry Participants to review the results of 
the 2010 operations and discuss village concerns. Immediately following 
the above meetings, the CAA provides that Industry Participants will 
provide a brief introduction of their planned activities for the 2011 
Season.
    Section 3 of the POC contains a commitment to community engagement 
and cooperation activities that is in keeping with the spirit of the 
CAA, including meetings before and after the Open Water Season. In 
particular, the POC provides that consultation, ``both formally and 
informally, will continue before, during, and after the 2010 seismic 
survey activities. Feedback from the marine mammal co-management group 
representatives and subsistence users is valued by Statoil and will be 
useful for our planned seismic survey and potential future 
activities.''
(2) Marine Mammal Observers and Communications
    Under Title II of the CAA, Industry Participants agree to employ 
MMOs/Inupiat Communicators (IC) on board each Primary Sound Source 
Vessel that they own or operate. The CAA provides detail about the 
general duties of the MMO/IC, including the duty to keep a lookout for 
bowhead whales and marine mammals in the vessels' vicinity, provide 
direct contact with subsistence whaling boats in the area to avoid 
conflict, and remain subject to the regular code of employee conduct on 
board the vessels. Title II of the CAA also covers responsibilities by 
Industry Participant vessels and subsistence hunting vessels to report 
in to appropriate Communications System Coordination Centers (Com-
Centers) at regular intervals, communicate between vessels, and use 
communication capabilities to further avoid conflict to aid Industry 
Participants to avoid areas of active whale hunts. The sections also 
cover the general operation scheme and protocol for Com-Centers, duties 
of Com-Center operators, and types of communications equipment to use.
    The POC, in section 4.2, contains detailed language about the use 
of MMOs and Inupiaq MMOs with Traditional Knowledge.
    Under the POC, at least five observers will be based aboard the 
seismic source vessel and at least three MMOs on the chase/monitoring 
vessels when there are 24 hours of daylight, decreasing as the hours of 
daylight decrease. Primary roles for MMOs are defined as monitoring for 
the presence of marine mammals during all daylight airgun operations 
and during any nighttime ramp-up of the airguns. The MP provides 
additional detail on the number of MMOs, crew rotations, and observer 
qualification and training requirements, as well as monitoring 
methodology, including protocols for poor visibility and night 
monitoring, use of specialized field equipment, field data-recording, 
verification, handling, and security, and field reporting. Lastly, the 
Participation Agreement provides that Statoil (and Shell) will fund a 
24/7 communications center staffed by Inupiat personnel. The center 
will have contact with all vessels at least once every hour.
(3) Vessel Operations
    Title III of the CAA covers vessel operations, including the duty 
of vessel operators to report to appropriate Com-Centers and notify 
them of operation plan changes. The section also provides measures for 
avoiding potential interaction with bowhead whales, as well as 
appropriate sound signature data for each vessel.
    Section 4.3 of the POC contains a discussion of mitigation measures 
that includes: using the best known technology and seismic equipment to 
minimize impacts; airgun array power down, shut down, and ramp-up 
procedures to be implemented; cost-sharing participation for Com-
Centers; the implementation of Awareness and Interaction Plans to lower 
the impact of seismic surveys on polar bear and walrus; monitoring ice 
conditions and movement; and supporting a search and rescue helicopter 
base as a part of the project plan. The MP contains significant detail 
on Statoil's agreement to mitigate impacts by adopting stringent safety 
and disturbance zones, and power down, shut down, and ramp-up 
protocols. The Participation Agreement discusses logistical support and 
shore services, including Statoil's pledge to share in the cost burden 
of maintaining the Wainwright ComCenter and protocols for operations of 
the Com-Center.
(4) Vessels, Testing, and Monitoring
    Title IV of the CAA covers equipment standards and requirements 
protocols for the sound signature tests, monitoring plans, the use of 
existing information, procedures for handling raw data gathered during 
tests, and cumulative noise impact studies.
    In the POC, section 2.2 provides detailed descriptions of the 
vessels to be used during the seismic survey. Section 4.1 provides 
additional detail regarding vessel and seismic equipment protocols to 
reduce impacts. Specifically, the POC pledges that Statoil will use the 
``best known technology and seismic equipment to minimize impacts to 
the environment,'' including: equipping vessels with the latest 
technology and waste management systems; using 12 streamers in the 
seismic receiver array to reduce the number of times the vessel

[[Page 49787]]

must traverse and the amount of shot points needed to cover the entire 
survey area; using solid streamers which do not contain contaminants 
that could leak.
(5) Avoiding Conflicts
    Title V of the CAA specifically centers on conflict avoidance, and 
contains guidelines for routing vessels and aircraft and limiting 
vessel speeds for the avoidance of bowhead whales and subsistence 
hunts, limitations for geophysical activity, and specific provisions 
for drilling and production.
    Section 3 of the POC, as discussed above, contains a significant 
commitment to cooperation activities and community engagement. In 
addition to the continuation of formal and informal consultation, the 
POC also contains measures outlining Statoil's commitment to continued 
engagement with marine mammal co-management groups and other community 
cooperation engagements far outside the scope of the CAA. For example, 
Statoil has participated in a JIP on Oil Spills in Ice, where Norwegian 
authorities allowed oil spills in broken ice, with the ultimate goal of 
developing more effective prevention and mitigation measures.
    In summary, the POC, 4MP, and Participation Agreement contain 
provisions that either directly match or match the spirit of those 
provisions of the CAA focused on avoiding conflicts between the 
industry and subsistence users; ensuring short and long-term 
cooperation and consultation with subsistence users; and commitments to 
ongoing scientific research of topics such as species distribution, 
seabed studies, and acoustic monitoring programs.
    NMFS has scrutinized all of the documents submitted by Statoil 
(e.g., IHA application, 4MP, Plan of Cooperation and other 
correspondence to NMFS and affected stakeholders) and documents 
submitted by other affected stakeholders and concluded that harassment 
of marine mammals incidental to Statoil's activities will not have more 
than a negligible impact on marine mammal stocks or an unmitigable 
adverse impact on the availability of marine mammals for taking for 
subsistence uses. This finding was based in large part on NMFS' 
definition of ``negligible impact,'' ``unmitigable adverse impact,'' 
the proposed mitigation and monitoring measures, the scope of 
activities proposed to be conducted, including time of year, location 
and presence of marine mammals in the project area, and Statoil's Plan 
of Cooperation.
    Besides bowhead whale hunting, beluga whales are hunted for 
subsistence at Barrow, Wainwright, Point Lay, and Point Hope, with the 
most taken by Point Lay (Fuller and George 1997). Harvest at all of 
these villages generally occurs between April and July with most taken 
in April and May when pack-ice conditions deteriorate and leads open-
up. Ringed, bearded, and spotted seals are hunted by all of the 
villages bordering the project area (Fuller and George 1997). Ringed 
and bearded seals are hunted throughout the year, but most are taken in 
May, June, and July when ice breaks up and there is open water instead 
of the more difficult hunting of seals at holes and lairs. Spotted 
seals are only hunted in spring through summer.
    In addition, the proposed seismic surveys by Statoil would only 
occur for a brief period of 60 days. It would also occur far offshore, 
approximately 70 miles, outside the area in which harvest traditionally 
occurs. NMFS does not expect subsistence users to be directly displaced 
by the seismic surveys because subsistence users typically do not 
travel this far offshore to harvest marine mammals. Moreover, because 
of the significant distance offshore and the lack of hunting in these 
areas, there is no expectation that any physical barriers would exist 
between marine mammals and subsistence users.
    Finally, the required mitigation and monitoring measures are 
expected to reduce any adverse impacts on marine mammals for taking for 
subsistence uses to the extent practicable. These measures include, but 
are not limited to, the 180 dB and 190 dB safety (shut-down/power-down) 
zones; a requirement to monitor the 160 dB isopleths for aggregations 
of 12 or more non-migratory balaenidae whales and when necessary shut-
down seismic airguns; reducing vessel speed to 10 knots or less when a 
vessel is within 300 yards of whales to avoid a collision; utilizing 
communication centers to avoid any conflict with subsistence hunting 
activities; and the use of marine mammal observers.
    Over the past several months, NMFS has worked with both Alaska 
Native communities and the industry, to the extent feasible, to resolve 
any Alaska Native concerns from the proposed open water marine and 
seismic surveys. These efforts include convening an open water 
stakeholders' meeting in Anchorage, AK, in March 2010, and multiple 
conference meetings with representatives of the Alaska Native 
communities and the industry.
    Comment 64: AEWC notes that, in 2009, NMFS did not publish its 
response to comments on proposed IHAs activities conducted during the 
open water season until well after the fall subsistence hunt at Cross 
Island had concluded and geophysical operations had already taken 
place. AEWC states that NMFS' failure to release its response to 
comments until after the activities had taken place casts serious doubt 
on the validity of NMFS' public involvement process and the underlying 
analysis of impacts to subsistence activities and marine mammals.
    Response: NMFS does not agree with AEWC's statement that NMFS' 
failure to release its response to comments until after the activities 
had taken place casts doubt on the validity of NMFS' public involvement 
process, or the underlying analysis of impacts to subsistence 
activities and marine mammals. As stated earlier, the decision to issue 
an IHA to Statoil for its proposed seismic surveys in the Chukchi Sea 
is based in large part on NMFS' definition of ``negligible impact,'' 
``unmitigable adverse impact,'' the proposed mitigation and monitoring 
measures, the scope of activities proposed to be conducted, including 
time of year, location and presence of marine mammals in the project 
area, extensive research and studies on potential impacts of 
anthropogenic sounds to marine mammals, marine mammal behavior, 
distribution, and movements in the vicinity of Statoil's proposed 
project areas, Statoil's Plan of Cooperation, and on public comments 
received during the commenting period and peer-review recommendations 
by an independent review panel. The reason that NMFS was not able to 
publish its response to comments on proposed IHA activities in 2009 for 
Shell's shallow hazards and site clearance surveys until the end of the 
survey activities was due to the large amount of comments NMFS 
received. NMFS was able to review and analyze all comments it received 
and address their validity for the issuance of the IHA. However, due to 
the large volume of comments, NMFS was not able to organize them into 
publishable format to be incorporated into the Federal Register notice 
for publication on a timely basis. NMFS will strive to make sure that 
in the future all comments are addressed in full and published by the 
time IHAs are issued, as NMFS has done for the 2010 open-water seismic 
IHAs.

Description of Marine Mammals in the Area of the Specified Activity

    Eight cetacean and four pinniped species under NMFS jurisdiction 
could occur in the general area of Statoil's open water marine seismic 
survey area

[[Page 49788]]

in the Chukchi Sea. The species most likely to occur in the project 
vicinity include two cetacean species: Beluga (Delphinapterus leucas) 
and bowhead whales (Balaena mysticetus), and three seal species: Ringed 
(Phoca hispida), spotted (P. largha), and bearded seals (Erignathus 
barbatus). Most encounters are likely to occur in nearshore shelf 
habitats or along the ice edge. The marine mammal species that is 
likely to be encountered most widely (in space and time) throughout the 
period of the open water seismic survey is the ringed seal. Encounters 
with bowhead and beluga whales are expected to be limited to particular 
regions and seasons, as discussed below.
    Other marine mammal species that have been observed in the Chukchi 
Sea but are less frequent or uncommon in the project area include 
harbor porpoise (Phocoena phocoena), narwhal (Monodon monoceros), 
killer whale (Orcinus orca), fin whale (Balaenoptera physalus), minke 
whale (B. acutorostrata), humpback whale (Megaptera novaeangliae), gray 
whale (Eschrichtius robustus), and ribbon seal (Histriophoca fasciata). 
These species could occur in the project area, but each of these 
species is uncommon or rare in the area and relatively few encounters 
with these species are expected during the proposed marine seismic 
survey. The narwhal occurs in Canadian waters and occasionally in the 
Beaufort Sea, but it is rare there and is not expected to be 
encountered. There are scattered records of narwhal in Alaskan waters, 
including reports by subsistence hunters, where the species is 
considered extralimital (Reeves et al. 2002). Point Barrow, Alaska, is 
the approximate northeastern extent of the harbor porpoise's regular 
range (Suydam and George 1992). Humpback, fin, and minke whales have 
recently been sighted in the Chukchi Sea but very rarely in the 
Beaufort Sea. Greene et al. (2007) reported and photographed a humpback 
whale cow/calf pair east of Barrow near Smith Bay in 2007, which is the 
first known occurrence of humpbacks in the Beaufort Sea. Savarese et 
al. (2009) reported one minke whale sighting in the Beaufort Sea in 
2007 and 2008. Ribbon seals do not normally occur in the Beaufort Sea; 
however, two ribbon seal sightings were reported during vessel-based 
activities near Prudhoe Bay in 2008 (Savarese et al. 2009).
    The bowhead, fin, and humpback whales are listed as ``endangered'' 
under the Endangered Species Act (ESA) and as depleted under the MMPA. 
Certain stocks or populations of gray, beluga, and killer whales and 
spotted seals are listed as endangered or proposed for listing under 
the ESA; however, none of those stocks or populations occur in the 
proposed activity area. Additionally, the ribbon seal is considered a 
``species of concern'' under the ESA, and the bearded and ringed seals 
are ``candidate species'' under the ESA, meaning they are currently 
being considered for listing.
    Statoil's application contains information on the status, 
distribution, seasonal distribution, and abundance of each of the 
species under NMFS jurisdiction mentioned in this document. Please 
refer to the application for that information (see ADDRESSES). 
Additional information can also be found in the NMFS Stock Assessment 
Reports (SAR). The Alaska 2009 SAR is available at: http://www.nmfs.noaa.gov/pr/pdfs/sars/ak2009.pdf.

Monitoring Plan Peer Review

    The MMPA requires that monitoring plans be independently peer 
reviewed ``where the proposed activity may affect the availability of a 
species or stock for taking for subsistence uses'' (16 U.S.C. 
1371(a)(5)(D)(ii)(III)). Regarding this requirement, NMFS' implementing 
regulations state, ``Upon receipt of a complete monitoring plan, and at 
its discretion, [NMFS] will either submit the plan to members of a peer 
review panel for review or within 60 days of receipt of the proposed 
monitoring plan, schedule a workshop to review the plan'' (50 CFR 
216.108(d)).
    NMFS convened an independent peer review panel to review Statoil's 
Marine Mammal Monitoring and Mitigation Plan (4MP) for the Marine 
Seismic Surveys of Selected Lease Areas in the Alaskan Chukchi Sea in 
2010. The panel met on March 25 and 26, 2010, and provided their final 
report to NMFS on April 22, 2010. The full panel report can be viewed 
at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications.
    NMFS provided the panel with Statoil's 4MP and asked the panel to 
address the following questions and issues for Statoil's plan:
    (1) The monitoring program should document the effects (including 
acoustic) on marine mammals and document or estimate the actual level 
of take as a result of the activity. Does the monitoring plan meet this 
goal?
    (2) Ensure that the monitoring activities and methods described in 
the plan will enable the applicant to meet the requirements listed in 
(1) above;
    (3) Are the applicant's objectives achievable based on the methods 
described in the plan?
    (4) Are the applicant's objectives the most useful for 
understanding impacts on marine mammals?
    (5) Should the applicant consider additional monitoring methods or 
modifications of proposed monitoring methods for the proposed activity? 
And
    (6) What is the best way for an applicant to report their data and 
results to NMFS?
    Section 3 of the report contains recommendations that the panel 
members felt were applicable to all of the monitoring plans reviewed 
this year. Section 4.6 of the report contains recommendations specific 
to Statoil's Open Water Marine Seismic Survey Program 4MP. 
Specifically, for the general recommendations, the panel commented on 
issues related to: (1) Acoustic effects of oil and gas exploration--
assessment and mitigation; (2) aerial surveys; (3) MMOs; (4) visual 
near-field monitoring; (5) visual far-field monitoring; (6) baseline 
biological and environmental information; (7) comprehensive ecosystem 
assessments and cumulative impacts; (8) duplication of seismic survey 
effort; and (9) whale behavior.
    NMFS has reviewed the report and evaluated all recommendations made 
by the panel. NMFS has determined that there are several measures that 
Statoil can incorporate into its 2010 Open Water Marine Survey Program 
4MP to improve it. Additionally, there are other recommendations that 
NMFS has determined would also result in better data collection, and 
could potentially be implemented by oil and gas industry applicants, 
but which likely could not be implemented for the 2010 open water 
season due to technical issues (see below). While it may not be 
possible to implement those changes this year, NMFS believes that they 
are worthwhile and appropriate suggestions that may require a bit more 
time to implement, and Statoil should consider incorporating them into 
future monitoring plans should Statoil decide to apply for IHAs in the 
future.
    The following subsections lay out measures that NMFS recommends for 
implementation as part of the 2010 Open Water Marine Survey Program 4MP 
and those that are recommended for future programs.

Recommendations for Inclusion in the 2010 4MP and IHA

    Section 3.3 of the panel report contains several recommendations 
regarding MMOs, which NMFS agrees that Statoil should incorporate:
     Observers should be trained using visual aids (e.g., 
videos, photos), to help them identify the species that they are

[[Page 49789]]

likely to encounter in the conditions under which the animals will 
likely be seen.
     Observers should understand the importance of classifying 
marine mammals as ``unknown'' or ``unidentified'' if they cannot 
identify the animals to species with confidence. In those cases, they 
should note any information that might aid in the identification of the 
marine mammal sighted. For example, for an unidentified mysticete 
whale, the observers should record whether the animal had a dorsal fin.
     Observers should attempt to maximize the time spent 
looking at the water and guarding the safety radii. They should avoid 
the tendency to spend too much time evaluating animal behavior or 
entering data on forms, both of which detract from their primary 
purpose of monitoring the safety zone.
     ``Big eye'' binoculars (25 x 150) should be used from high 
perches on large, stable platforms. They are most useful for monitoring 
impact zones that extend beyond the effective line of sight. With two 
or three observers on watch, the use of ``big eyes'' should be paired 
with searching by naked eye, the latter allowing visual coverage of 
nearby areas to detect marine mammals. When a single observer is on 
duty, the observer should follow a regular schedule of shifting between 
searching by naked-eye, low-power binoculars, and ``big-eye'' 
binoculars based on the activity, the environmental conditions, and the 
marine mammals of concern.
     Observers should use the best possible positions for 
observing (e.g., outside and as high on the vessel as possible), taking 
into account weather and other working conditions.
     Whenever possible, new observers should be paired with 
experienced observers to avoid situations where lack of experience 
impairs the quality of observations. If there are Alaska Native MMOs, 
the MMO training that is conducted prior to the start of the survey 
activities should be conducted with both Alaska Native MMOs and 
biologist MMOs being trained at the same time in the same room. There 
should not be separate training courses for the different MMOs.
    In Section 3.4, panelists recommend collecting some additional data 
to help verify the utility of the ``ramp-up'' requirement commonly 
contained in IHAs. To help evaluate the utility of ramp-up procedures, 
NMFS will require observers to record and report their observations 
during any ramp-up period. An analysis of these observations may lead 
to additional information regarding the effectiveness of ramp-up and 
should be included in the monitoring report.
    Among other things, Section 3.5 of the panel report recommends 
recording visibility data because of the concern that the line-of-sight 
distance for observing marine mammals is reduced under certain 
conditions. MMOs should ``carefully document visibility during 
observation periods so that total estimates of take can be corrected 
accordingly''.
    Section 4.6 of the report contains recommendations specific to 
Statoil's Open Water Marine Seismic Survey Program 4MP. Of the 
recommendations presented in this section, NMFS has determined that the 
following should be implemented for the 2010 season:
     Summarize observation effort and conditions, the number of 
animals seen by species, the location and time of each sighting, 
position relative to the survey vessel, the company's activity at the 
time, each animal's response, and any adjustments made to operating 
procedures. Provide all spatial data on charts (always including vessel 
location).
     Make all data available in the report or (preferably) 
electronically for integration with data from other companies.
     Accommodate specific requests for raw data, including 
tracks of all vessels and aircraft associated with the operation and 
activity logs documenting when and what types of sounds are introduced 
into the environment by the operation.
    NMFS spoke with Statoil about the inclusion of these 
recommendations into the 2010 4MP and IHA. Statoil indicated to NMFS 
that they will incorporate these recommendations into the 4MP, and NMFS 
has made several of these recommendations requirements in the IHA.

Recommendations for Inclusion in Future Monitoring Plans

    Section 3.5 of the report recommends methods for conducting 
comprehensive monitoring of a large-scale seismic operation. One method 
for conducting this monitoring recommended by panel members is the use 
of passive acoustic devices. Additionally, Section 3.2 of the report 
encourages the use of such systems if aerial surveys will not be used 
for real-time mitigation monitoring. NMFS acknowledges that there are 
challenges involved in using this technology to detect bowhead whale 
vocalizations in conjunction with seismic airguns in this environment, 
especially in real time. However, NMFS recommends that Statoil work to 
help develop and improve this type of technology for use in the Arctic 
(and use it once it is available and effective), as it could be 
valuable both for real-time mitigation implementation, as well as 
archival data collection. Statoil indicated to NMFS that they have been 
working for several years to aid in the development of such technology 
and will continue to do so.
    The panelists also recommend adding a tagging component to 
monitoring plans. ``Tagging of animals expected to be in the area where 
the survey is planned also may provide valuable information on the 
location of potentially affected animals and their behavioral responses 
to industrial activities. Although the panel recognized that such 
comprehensive monitoring might be difficult and expensive, such an 
effort (or set of efforts) reflects the complex nature of the challenge 
of conducting reliable, comprehensive monitoring for seismic or other 
relatively-intense industrial operations that ensonify large areas of 
ocean.'' While this particular recommendation is not feasible for 
implementation in 2010, NMFS recommends that Statoil consider adding a 
tagging component to future seismic survey monitoring plans should 
Statoil decide to conduct such activities in future years.
    To the extent possible, NMFS recommends implementing the 
recommendation contained in Section 4.6.6 for the 2010 season: 
``Integrate all observer data with information from tagging and 
acoustic studies to provide a more comprehensive description of the 
acoustic environment during its survey.'' However, NMFS recognizes that 
this integration process may take time to implement. Therefore, Statoil 
should begin considering methods for the integration of the observer 
data now if Statoil intends to apply for IHAs in the future.
    In Section 3.4, panelists recommend collecting data to evaluate the 
efficacy of using forward-looking infrared devices (FLIR) vs. night-
vision binoculars. The panelists note that while both of these devices 
may increase detection capabilities by MMOs of marine mammals, the 
reliability of these technologies should be tested under appropriate 
conditions and their efficacy evaluated. NMFS recommends that Statoil 
design a study to explore using both FLIR and night-vision binoculars 
and collect data on levels of detection of marine mammals using each 
type of device.

Other Recommendations in the Report

    The panel also made several recommendations, which are not

[[Page 49790]]

discussed in the two preceding subsections. NMFS determined that many 
of the recommendations were made beyond the bounds of what the panel 
members were tasked to do. For example, the panel recommended that NMFS 
begin a transition away from using a single metric of acoustic exposure 
to estimate the potential effects of anthropogenic sound on marine 
living resources. This is not a recommendation about monitoring but 
rather addresses a NMFS policy issue. NMFS is currently in the process 
of revising its acoustic guidelines on a national scale. A 
recommendation was also made regarding the training and oversight of 
MMOs. NMFS is currently working on a national policy for this as well. 
Section 3.7 of the report contains several recommendations regarding 
comprehensive ecosystem assessments and cumulative impacts. These are 
good, broad recommendations; however, the implementation of these 
recommendations would not be the responsibility solely of oil and gas 
industry applicants. The recommendations require the cooperation and 
input of several groups, including Federal, state, and local government 
agencies, members of other industries, and members of the scientific 
research community. NMFS will encourage the industry and others to 
build the relationships and infrastructure necessary to pursue these 
goals, and incorporate these recommendations into future MMPA 
authorizations, as appropriate. Lastly, Section 3.8 of the report makes 
a recommendation regarding data sharing and reducing the duplication of 
seismic survey effort. While this is a valid recommendation, it does 
not relate to monitoring or address any of the six questions which the 
panel members were tasked to answer.
    For some of the recommendations, NMFS felt that additional 
clarification was required by the panel members before NMFS could 
determine whether or not applicants should incorporate them into the 
monitoring plans. Section 3.2 of the report discusses the use of and 
methods for conducting aerial surveys. Industry applicants have not 
conducted aerial surveys in Chukchi Sea lease sale areas for several 
years because of the increased risk for flying there (as noted by the 
panel report). To that end, NMFS has asked the panel to provide 
recommendations on whether or not similar surveys could be conducted 
from dedicated vessel-based platforms. NMFS also asked for additional 
clarification on some of the recommendations regarding data collection 
and take estimate calculations. In addition, NMFS asked the panel 
members for clarification on the recommendation contained in Section 
3.6 regarding baseline studies. Lastly, NMFS asked the panel members 
for clarification on the recommendation specific to Statoil contained 
in Section 4.6 regarding estimating statistical power for all methods 
intended to detect adverse impacts. Once NMFS hears back from the panel 
and is clear with these recommendations, NMFS will follow up with 
Statoil and discuss the implementation of these additional measures in 
future years.

Potential Effects of the Specified Activity on Marine Mammals

    Operating a variety of active acoustic sources such as airguns and 
echo sounders can impact marine mammals in a variety of ways.

Potential Effects of Airgun and Sonar Sounds on Marine Mammals

    The effects of sounds from airgun pulses might include one or more 
of the following: Tolerance, masking of natural sounds, behavioral 
disturbance, and temporary or permanent hearing impairment or non-
auditory effects (Richardson et al. 1995). As outlined in previous NMFS 
documents, the effects of noise on marine mammals are highly variable, 
and can be categorized as follows (based on Richardson et al. 1995):
(1) Tolerance
    Numerous studies have shown that pulsed sounds from airguns are 
often readily detectable in the water at distances of many kilometers. 
Numerous studies have also shown that marine mammals at distances more 
than a few kilometers from operating seismic vessels often show no 
apparent response. That is often true even in cases when the pulsed 
sounds must be readily audible to the animals based on measured 
received levels and the hearing sensitivity of that mammal group. 
Although various baleen whales, toothed whales, and (less frequently) 
pinnipeds have been shown to react behaviorally to airgun pulses under 
some conditions, at other times, mammals of all three types have shown 
no overt reactions. In general, pinnipeds and small odontocetes seem to 
be more tolerant of exposure to airgun pulses than baleen whales.
(2) Behavioral Disturbance
    Marine mammals may behaviorally react to sound when exposed to 
anthropogenic noise. These behavioral reactions are often shown as: 
Changing durations of surfacing and dives, number of blows per 
surfacing, or moving direction and/or speed; reduced/increased vocal 
activities; changing/cessation of certain behavioral activities (such 
as socializing or feeding); visible startle response or aggressive 
behavior (such as tail/fluke slapping or jaw clapping); avoidance of 
areas where noise sources are located; and/or flight responses (e.g., 
pinnipeds flushing into water from haulouts or rookeries).
    The biological significance of many of these behavioral 
disturbances is difficult to predict, especially if the detected 
disturbances appear minor. However, the consequences of behavioral 
modification could be expected to be biologically significant if the 
change affects growth, survival, and reproduction. Some of these 
significant behavioral modifications include:
     Drastic change in diving/surfacing patterns (such as those 
thought to be causing beaked whale stranding due to exposure to 
military mid-frequency tactical sonar);
     Habitat abandonment due to loss of desirable acoustic 
environment; and
     Cease feeding or social interaction.
    For example, at the Guerreo Negro Lagoon in Baja California, 
Mexico, which is one of the important breeding grounds for Pacific gray 
whales, shipping and dredging associated with a salt works may have 
induced gray whales to abandon the area through most of the 1960s 
(Bryant et al. 1984). After these activities stopped, the lagoon was 
reoccupied, first by single whales and later by cow-calf pairs.
    The onset of behavioral disturbance from anthropogenic noise 
depends on both external factors (characteristics of noise sources and 
their paths) and the receiving animals (hearing, motivation, 
experience, demography) and is also difficult to predict (Southall et 
al. 2007).
    Currently NMFS uses 160 dB re 1 [mu]Pa at received level for 
impulse noises (such as airgun pulses) as the onset of marine mammal 
behavioral harassment.
    Mysticete: Baleen whales generally tend to avoid operating airguns, 
but avoidance radii are quite variable. Whales are often reported to 
show no overt reactions to airgun pulses at distances beyond a few 
kilometers, even though the airgun pulses remain well above ambient 
noise levels out to much longer distances (reviewed in Richardson et 
al. 1995; Gordon et al. 2004). However, studies done since the late 
1990s of migrating humpback and migrating bowhead whales show 
reactions, including avoidance, that sometimes extend to greater 
distances than documented earlier. Therefore, it

[[Page 49791]]

appears that behavioral disturbance can vary greatly depending on 
context, and not just on received levels alone. Avoidance distances 
often exceed the distances at which boat-based observers can see 
whales, so observations from the source vessel can be biased. 
Observations over broader areas may be needed to determine the range of 
potential effects of some large-source seismic surveys where effects on 
cetaceans may extend to considerable distances (Richardson et al. 1999; 
Moore and Angliss 2006). Longer-range observations, when required, can 
sometimes be obtained via systematic aerial surveys or aircraft-based 
observations of behavior (e.g., Richardson et al. 1986, 1999; Miller et 
al. 1999, 2005; Yazvenko et al. 2007a, 2007b) or by use of observers on 
one or more support vessels operating in coordination with the seismic 
vessel (e.g., Smultea et al. 2004; Johnson et al. 2007). However, the 
presence of other vessels near the source vessel can, at least at 
times, reduce sightability of cetaceans from the source vessel (Beland 
et al. 2009), thus complicating interpretation of sighting data.
    Some baleen whales show considerable tolerance of seismic pulses. 
However, when the pulses are strong enough, avoidance or other 
behavioral changes become evident. Because the responses become less 
obvious with diminishing received sound level, it has been difficult to 
determine the maximum distance (or minimum received sound level) at 
which reactions to seismic pulses become evident and, hence, how many 
whales are affected.
    Studies of gray, bowhead, and humpback whales have determined that 
received levels of pulses in the 160-170 dB re 1 [mu]Pa (rms) range 
seem to cause obvious avoidance behavior in a substantial fraction of 
the animals exposed (see review in Southall et al. 2007). In many 
areas, seismic pulses diminish to these levels at distances ranging 
from 4-15 km from the source. A substantial proportion of the baleen 
whales within such distances may show avoidance or other strong 
disturbance reactions to the operating airgun array. However, in other 
situations, various mysticetes tolerate exposure to full-scale airgun 
arrays operating at even closer distances, with only localized 
avoidance and minor changes in activities. At the other extreme, in 
migrating bowhead whales, avoidance often extends to considerably 
larger distances (20-30 km) and lower received sound levels (120-130 dB 
re 1 [mu]Pa (rms)). Also, even in cases where there is no conspicuous 
avoidance or change in activity upon exposure to sound pulses from 
distant seismic operations, there are sometimes subtle changes in 
behavior (e.g., surfacing-respiration-dive cycles) that are only 
evident through detailed statistical analysis (e.g., Richardson et al. 
1986; Gailey et al. 2007).
    Data on short-term reactions by cetaceans to impulsive noises are 
not necessarily indicative of long-term or biologically significant 
effects. It is not known whether impulsive sounds affect reproductive 
rate or distribution and habitat use in subsequent days or years. 
However, gray whales have continued to migrate annually along the west 
coast of North America despite intermittent seismic exploration (and 
much ship traffic) in that area for decades (Appendix A in Malme et al. 
1984; Richardson et al. 1995), and there has been a substantial 
increase in the population over recent decades (Allen and Angliss 
2010). The western Pacific gray whale population did not seem affected 
by a seismic survey in its feeding ground during a prior year (Johnson 
et al. 2007). Similarly, bowhead whales have continued to travel to the 
eastern Beaufort Sea each summer despite seismic exploration in their 
summer and autumn range for many years (Richardson et al. 1987), and 
their numbers have increased notably (Allen and Angliss 2010). Bowheads 
also have been observed over periods of days or weeks in areas 
ensonified repeatedly by seismic pulses (Richardson et al. 1987; Harris 
et al. 2007). However, it is generally not known whether the same 
individual bowheads were involved in these repeated observations 
(within and between years) in strongly ensonified areas. In any event, 
in the absence of some unusual circumstances, the history of 
coexistence between seismic surveys and baleen whales suggests that 
brief exposures to sound pulses from any single seismic survey are 
unlikely to result in prolonged effects.
    Odontocete: Little systematic information is available about 
reactions of toothed whales to airgun pulses. Few studies similar to 
the more extensive baleen whale/seismic pulse work summarized above 
have been reported for toothed whales. However, there are recent 
systematic data on sperm whales (e.g., Gordon et al. 2006; Madsen et 
al. 2006; Winsor and Mate 2006; Jochens et al. 2008; Miller et al. 
2009). There is also an increasing amount of information about 
responses of various odontocetes to seismic surveys based on monitoring 
studies (e.g., Stone 2003; Smultea et al. 2004; Moulton and Miller 
2005; Bain and Williams 2006; Holst et al. 2006; Stone and Tasker 2006; 
Potter et al. 2007; Hauser et al. 2008; Holst and Smultea 2008; Weir 
2008; Barkaszi et al. 2009; Richardson et al. 2009).
    Dolphins and porpoises are often seen by observers on active 
seismic vessels, occasionally at close distances (e.g., bow riding). 
However, some studies near the U.K., Newfoundland and Angola, in the 
Gulf of Mexico, and off Central America have shown localized avoidance. 
Also, belugas summering in the Canadian Beaufort Sea showed larger-
scale avoidance, tending to avoid waters out to 10-20 km from operating 
seismic vessels. In contrast, recent studies show little evidence of 
conspicuous reactions by sperm whales to airgun pulses, contrary to 
earlier indications.
    There are almost no specific data on responses of beaked whales to 
seismic surveys, but it is likely that most if not all species show 
strong avoidance. There is increasing evidence that some beaked whales 
may strand after exposure to strong noise from tactical military mid-
frequency sonars. Whether they ever do so in response to seismic survey 
noise is unknown. Northern bottlenose whales seem to continue to call 
when exposed to pulses from distant seismic vessels.
    For delphinids, and possibly the Dall's porpoise, the available 
data suggest that a >=170 dB re 1 [mu]Pa (rms) disturbance criterion 
(rather than >=160 dB) would be appropriate. With a medium-to-large 
airgun array, received levels typically diminish to 170 dB within 1-4 
km, whereas levels typically remain above 160 dB out to 4-15 km (e.g., 
Tolstoy et al. 2009). Reaction distances for delphinids are more 
consistent with the typical 170 dB re 1 [mu]Pa rms distances.
    Due to their relatively higher frequency hearing ranges when 
compared to mysticetes, odontocetes may have stronger responses to mid- 
and high-frequency sources such as sub-bottom profilers, side scan 
sonar, and echo sounders than mysticetes (Richardson et al. 1995; 
Southall et al. 2007).
    Pinnipeds: Few studies of the reactions of pinnipeds to noise from 
open-water seismic exploration have been published (for review of the 
early literature, see Richardson et al. 1995). However, pinnipeds have 
been observed during a number of seismic monitoring studies. Monitoring 
in the Beaufort Sea during 1996-2002 provided a substantial amount of 
information on avoidance responses (or lack thereof) and associated 
behavior. Additional monitoring of that type has been done in the 
Beaufort and Chukchi Seas in 2006-2009. Pinnipeds exposed to seismic 
surveys have also been observed

[[Page 49792]]

during seismic surveys along the U.S. west coast. Some limited data are 
available on physiological responses of pinnipeds exposed to seismic 
sound, as studied with the aid of radio telemetry. Also, there are data 
on the reactions of pinnipeds to various other related types of 
impulsive sounds.
    Early observations provided considerable evidence that pinnipeds 
are often quite tolerant of strong pulsed sounds. During seismic 
exploration off Nova Scotia, gray seals exposed to noise from airguns 
and linear explosive charges reportedly did not react strongly (J. 
Parsons in Greene et al. 1985). An airgun caused an initial startle 
reaction among South African fur seals but was ineffective in scaring 
them away from fishing gear. Pinnipeds in both water and air sometimes 
tolerate strong noise pulses from non-explosive and explosive scaring 
devices, especially if attracted to the area for feeding or 
reproduction (Mate and Harvey 1987; Reeves et al. 1996). Thus, 
pinnipeds are expected to be rather tolerant of, or to habituate to, 
repeated underwater sounds from distant seismic sources, at least when 
the animals are strongly attracted to the area.
    In summary, visual monitoring from seismic vessels has shown only 
slight (if any) avoidance of airguns by pinnipeds, and only slight (if 
any) changes in behavior. These studies show that many pinnipeds do not 
avoid the area within a few hundred meters of an operating airgun 
array. However, based on the studies with large sample size, or 
observations from a separate monitoring vessel, or radio telemetry, it 
is apparent that some phocid seals do show localized avoidance of 
operating airguns. The limited nature of this tendency for avoidance is 
a concern. It suggests that one cannot rely on pinnipeds to move away, 
or to move very far away, before received levels of sound from an 
approaching seismic survey vessel approach those that may cause hearing 
impairment.
(3) Masking
    Chronic exposure to excessive, though not high-intensity, noise 
could cause masking at particular frequencies for marine mammals that 
utilize sound for vital biological functions. Masking can interfere 
with detection of acoustic signals such as communication calls, 
echolocation sounds, and environmental sounds important to marine 
mammals. Since marine mammals depend on acoustic cues for vital 
biological functions, such as orientation, communication, finding prey, 
and avoiding predators, marine mammals that experience severe acoustic 
masking will have reduced fitness in survival and reproduction.
    Masking occurs when noise and signals (that animal utilizes) 
overlap at both spectral and temporal scales. For the airgun noise 
generated from the proposed marine seismic survey, these are low 
frequency (under 1 kHz) pulses with extremely short durations (in the 
scale of milliseconds). Lower frequency man-made noises are more likely 
to affect detection of communication calls and other potentially 
important natural sounds such as surf and prey noise. There is little 
concern regarding masking due to the brief duration of these pulses and 
relatively longer silence between airgun shots (9-12 seconds) near the 
noise source, however, at long distances (over tens of kilometers away) 
in deep water, due to multipath propagation and reverberation, the 
durations of airgun pulses can be ``stretched'' to seconds with long 
decays (Madsen et al. 2006; Clark and Gagnon 2006). Therefore it could 
affect communication signals used by low frequency mysticetes when they 
occur near the noise band and thus reduce the communication space of 
animals (e.g., Clark et al. 2009a, 2009b) and cause increased stress 
levels (e.g., Foote et al. 2004; Holt et al. 2009). Further, in areas 
of shallow water, multipath propagation of airgun pulses could be more 
profound, thus affecting communication signals from marine mammals even 
at close distances. Although average ambient noise in areas where 
received seismic noises are heard can be elevated at long distances, 
the intensity of the noise is also greatly reduced at such long 
distances. Nevertheless, partial informational and energetic masking of 
different degrees could affect signal receiving in some marine mammals 
within the ensonified areas. Additional research is needed to further 
address these effects.
    Although masking effects of pulsed sounds on marine mammal calls 
and other natural sounds are expected to be limited, there are few 
specific studies on this. Some whales continue calling in the presence 
of seismic pulses and whale calls often can be heard between the 
seismic pulses (e.g., Richardson et al. 1986; McDonald et al. 1995; 
Greene et al. 1999a, 1999b; Nieukirk et al. 2004; Smultea et al. 2004; 
Holst et al. 2005a, 2005b, 2006; Dunn and Hernandez 2009). However, 
there is one recent summary report indicating that calling fin whales 
distributed in one part of the North Atlantic went silent for an 
extended period starting soon after the onset of a seismic survey in 
the area (Clark and Gagnon 2006). It is not clear from that preliminary 
paper whether the whales ceased calling because of masking, or whether 
this was a behavioral response not directly involving masking. Also, 
bowhead whales in the Beaufort Sea may decrease their call rates in 
response to seismic operations, although movement out of the area might 
also have contributed to the lower call detection rate (Blackwell et 
al. 2009a; 2009b).
    Among the odontocetes, there has been one report that sperm whales 
ceased calling when exposed to pulses from a very distant seismic ship 
(Bowles et al. 1994). However, more recent studies of sperm whales 
found that they continued calling in the presence of seismic pulses 
(Madsen et al. 2002; Tyack et al. 2003; Smultea et al. 2004; Holst et 
al. 2006; Jochens et al. 2008). Madsen et al. (2006) noted that airgun 
sounds would not be expected to mask sperm whale calls given the 
intermittent nature of airgun pulses. Dolphins and porpoises are also 
commonly heard calling while airguns are operating (Gordon et al. 2004; 
Smultea et al. 2004; Holst et al. 2005a, 2005b; Potter et al. 2007). 
Masking effects of seismic pulses are expected to be negligible in the 
case of the smaller odontocetes, given the intermittent nature of 
seismic pulses plus the fact that sounds important to them are 
predominantly at much higher frequencies than are the dominant 
components of airgun sounds.
    Pinnipeds have best hearing sensitivity and/or produce most of 
their sounds at frequencies higher than the dominant components of 
airgun sound, but there is some overlap in the frequencies of the 
airgun pulses and the calls. However, the intermittent nature of airgun 
pulses presumably reduces the potential for masking.
    Marine mammals are thought to be able to compensate for masking by 
adjusting their acoustic behavior such as shifting call frequencies, 
increasing call volume and vocalization rates. For example, blue whales 
are found to increase call rates when exposed to seismic survey noise 
in the St. Lawrence Estuary (Di Iorio and Clark 2009). The North 
Atlantic right whales (Eubalaena glacialis) exposed to high shipping 
noise increase call frequency (Parks et al. 2007), while some humpback 
whales respond to low-frequency active sonar playbacks by increasing 
song length (Miller el al. 2000).
(4) Hearing Impairment
    Marine mammals exposed to high intensity sound repeatedly or for 
prolonged periods can experience hearing threshold shift (TS), which is 
the loss of hearing sensitivity at certain frequency ranges (Kastak et 
al. 1999;

[[Page 49793]]

Schlundt et al. 2000; Finneran et al. 2002; 2005). TS can be permanent 
(PTS), in which case the loss of hearing sensitivity is unrecoverable, 
or temporary (TTS), in which case the animal's hearing threshold will 
recover over time (Southall et al. 2007). Just like masking, marine 
mammals that suffer from PTS or TTS will have reduced fitness in 
survival and reproduction, either permanently or temporarily. Repeated 
noise exposure that leads to TTS could cause PTS. For transient sounds, 
the sound level necessary to cause TTS is inversely related to the 
duration of the sound.


    TTS is the mildest form of hearing impairment that can occur during 
exposure to a strong sound (Kryter 1985). While experiencing TTS, the 
hearing threshold rises and a sound must be stronger in order to be 
heard. It is a temporary phenomenon, and (especially when mild) is not 
considered to represent physical damage or ``injury'' (Southall et al. 
2007). Rather, the onset of TTS is an indicator that, if the animal is 
exposed to higher levels of that sound, physical damage is ultimately a 
possibility.
    The magnitude of TTS depends on the level and duration of noise 
exposure, and to some degree on frequency, among other considerations 
(Kryter 1985; Richardson et al. 1995; Southall et al. 2007). For sound 
exposures at or somewhat above the TTS threshold, hearing sensitivity 
recovers rapidly after exposure to the noise ends. In terrestrial 
mammals, TTS can last from minutes or hours to (in cases of strong TTS) 
days. Only a few data have been obtained on sound levels and durations 
necessary to elicit mild TTS in marine mammals (none in mysticetes), 
and none of the published data concern TTS elicited by exposure to 
multiple pulses of sound during operational seismic surveys (Southall 
et al. 2007).
    For toothed whales, experiments on a bottlenose dolphin (Tursiops 
truncates) and beluga whale showed that exposure to a single watergun 
impulse at a received level of 207 kPa (or 30 psi) peak-to-peak (p-p), 
which is equivalent to 228 dB re 1 [mu]Pa (p-p), resulted in a 7 and 6 
dB TTS in the beluga whale at 0.4 and 30 kHz, respectively. Thresholds 
returned to within 2 dB of the pre-exposure level within 4 minutes of 
the exposure (Finneran et al. 2002). No TTS was observed in the 
bottlenose dolphin.
    Finneran et al. (2005) further examined the effects of tone 
duration on TTS in bottlenose dolphins. Bottlenose dolphins were 
exposed to 3 kHz tones (non-impulsive) for periods of 1, 2, 4 or 8 
seconds (s), with hearing tested at 4.5 kHz. For 1-s exposures, TTS 
occurred with SELs of 197 dB, and for exposures >1 s, SEL >195 dB 
resulted in TTS (SEL is equivalent to energy flux, in dB re 1 
[mu]Pa\2\-s). At an SEL of 195 dB, the mean TTS (4 min after exposure) 
was 2.8 dB. Finneran et al. (2005) suggested that an SEL of 195 dB is 
the likely threshold for the onset of TTS in dolphins and belugas 
exposed to tones of durations 1-8 s (i.e., TTS onset occurs at a near-
constant SEL, independent of exposure duration). That implies that, at 
least for non-impulsive tones, a doubling of exposure time results in a 
3 dB lower TTS threshold.
    However, the assumption that, in marine mammals, the occurrence and 
magnitude of TTS is a function of cumulative acoustic energy (SEL) is 
probably an oversimplification. Kastak et al. (2005) reported 
preliminary evidence from pinnipeds that, for prolonged non-impulse 
noise, higher SELs were required to elicit a given TTS if exposure 
duration was short than if it was longer, i.e., the results were not 
fully consistent with an equal-energy model to predict TTS onset. 
Mooney et al. (2009a) showed this in a bottlenose dolphin exposed to 
octave-band non-impulse noise ranging from 4 to 8 kHz at SPLs of 130 to 
178 dB re 1 [mu]Pa for periods of 1.88 to 30 minutes (min). Higher SELs 
were required to induce a given TTS if exposure duration was short than 
if it was longer. Exposure of the aforementioned bottlenose dolphin to 
a sequence of brief sonar signals showed that, with those brief (but 
non-impulse) sounds, the received energy (SEL) necessary to elicit TTS 
was higher than was the case with exposure to the more prolonged 
octave-band noise (Mooney et al. 2009b). Those authors concluded that, 
when using (non-impulse) acoustic signals of duration 0.5 s, SEL must 
be at least 210-214 dB re 1 [mu]Pa2-s to induce TTS in the bottlenose 
dolphin. The most recent studies conducted by Finneran et al. also 
support the notion that exposure duration has a more significant 
influence compared to SPL as the duration increases, and that TTS 
growth data are better represented as functions of SPL and duration 
rather than SEL alone (Finneran et al. 2010a, 2010b). In addition, 
Finneran et al. (2010b) conclude that when animals are exposed to 
intermittent noises, there is recovery of hearing during the quiet 
intervals between exposures through the accumulation of TTS across 
multiple exposures. Such findings suggest that when exposed to multiple 
seismic pulses, partial hearing recovery also occurs during the seismic 
pulse intervals.
    For baleen whales, there are no data, direct or indirect, on levels 
or properties of sound that are required to induce TTS. The frequencies 
to which baleen whales are most sensitive are lower than those to which 
odontocetes are most sensitive, and natural ambient noise levels at 
those low frequencies tend to be higher (Urick 1983). As a result, 
auditory thresholds of baleen whales within their frequency band of 
best hearing are believed to be higher (less sensitive) than are those 
of odontocetes at their best frequencies (Clark and Ellison 2004). From 
this, it is suspected that received levels causing TTS onset may also 
be higher in baleen whales. However, no cases of TTS are expected given 
the small size of the airguns proposed to be used and the strong 
likelihood that baleen whales (especially migrating bowheads) would 
avoid the approaching airguns (or vessel) before being exposed to 
levels high enough for there to be any possibility of TTS.
    In pinnipeds, TTS thresholds associated with exposure to brief 
pulses (single or multiple) of underwater sound have not been measured. 
Initial evidence from prolonged exposures suggested that some pinnipeds 
may incur TTS at somewhat lower received levels than do small 
odontocetes exposed for similar durations (Kastak et al. 1999; 2005). 
However, more recent indications are that TTS onset in the most 
sensitive pinniped species studied (harbor seal, which is closely 
related to the ringed seal) may occur at a similar SEL as in 
odontocetes (Kastak et al. 2004).
    Most cetaceans show some degree of avoidance of seismic vessels 
operating an airgun array (see above). It is unlikely that these 
cetaceans would be exposed to airgun pulses at a sufficiently high 
level for a sufficiently long period to cause more than mild TTS, given 
the relative movement of the vessel and the marine mammal. TTS would be 
more likely in any odontocetes that bow- or wake-ride or otherwise 
linger near the airguns. However, while bow- or wake-riding, 
odontocetes would be at the surface and thus not exposed to strong 
sound pulses given the pressure release and Lloyd Mirror effects at the 
surface. But if bow- or wake-riding animals were to dive intermittently 
near airguns, they would be exposed to strong sound pulses, possibly 
repeatedly.
    If some cetaceans did incur mild or moderate TTS through exposure 
to airgun sounds in this manner, this would very likely be a temporary 
and

[[Page 49794]]

reversible phenomenon. However, even a temporary reduction in hearing 
sensitivity could be deleterious in the event that, during that period 
of reduced sensitivity, a marine mammal needed its full hearing 
sensitivity to detect approaching predators, or for some other reason.
    Some pinnipeds show avoidance reactions to airguns, but their 
avoidance reactions are generally not as strong or consistent as those 
of cetaceans. Pinnipeds occasionally seem to be attracted to operating 
seismic vessels. There are no specific data on TTS thresholds of 
pinnipeds exposed to single or multiple low-frequency pulses. However, 
given the indirect indications of a lower TTS threshold for the harbor 
seal than for odontocetes exposed to impulse sound (see above), it is 
possible that some pinnipeds close to a large airgun array could incur 
TTS.
    Current NMFS' noise exposure standards require that cetaceans and 
pinnipeds should not be exposed to pulsed underwater noise at received 
levels exceeding, respectively, 180 and 190 dB re 1 [micro]Pa (rms). 
These criteria were taken from recommendations by an expert panel of 
the High Energy Seismic Survey (HESS) Team that performed an assessment 
on noise impacts by seismic airguns to marine mammals in 1997, although 
the HESS Team recommended a 180-dB limit for pinnipeds in California 
(HESS 1999). The 180 and 190 dB re 1 [mu]Pa (rms) levels have not been 
considered to be the levels above which TTS might occur. Rather, they 
were the received levels above which, in the view of a panel of 
bioacoustics specialists convened by NMFS before TTS measurements for 
marine mammals started to become available, one could not be certain 
that there would be no injurious effects, auditory or otherwise, to 
marine mammals. As summarized above, data that are now available imply 
that TTS is unlikely to occur in various odontocetes (and probably 
mysticetes as well) unless they are exposed to a sequence of several 
airgun pulses stronger than 190 dB re 1 [mu]Pa (rms). On the other 
hand, for the harbor seal, harbor porpoise, and perhaps some other 
species, TTS may occur upon exposure to one or more airgun pulses whose 
received level equals the NMFS ``do not exceed'' value of 190 dB re 1 
[mu]Pa (rms). That criterion corresponds to a single-pulse SEL of 175-
180 dB re 1 [mu]Pa\2\-s in typical conditions, whereas TTS is suspected 
to be possible in harbor seals and harbor porpoises with a cumulative 
SEL of ~171 and ~164 dB re 1 [mu]Pa\2\-s, respectively.
    It has been shown that most large whales and many smaller 
odontocetes (especially the harbor porpoise) show at least localized 
avoidance of ships and/or seismic operations. Even when avoidance is 
limited to the area within a few hundred meters of an airgun array, 
that should usually be sufficient to avoid TTS based on what is 
currently known about thresholds for TTS onset in cetaceans. In 
addition, ramping up airgun arrays, which is standard operational 
protocol for many seismic operators, should allow cetaceans near the 
airguns at the time of startup (if the sounds are aversive) to move 
away from the seismic source and to avoid being exposed to the full 
acoustic output of the airgun array. Thus, most baleen whales likely 
will not be exposed to high levels of airgun sounds provided the ramp-
up procedure is applied. Likewise, many odontocetes close to the 
trackline are likely to move away before the sounds from an approaching 
seismic vessel become sufficiently strong for there to be any potential 
for TTS or other hearing impairment. Hence, there is little potential 
for baleen whales or odontocetes that show avoidance of ships or 
airguns to be close enough to an airgun array to experience TTS. 
Therefore, it is not likely that marine mammals in the vicinity of the 
proposed open water marine and seismic surveys by Shell and Statoil 
would experience TTS as a result of these activities.

PTS

    When PTS occurs, there is physical damage to the sound receptors in 
the ear. In some cases, there can be total or partial deafness, whereas 
in other cases, the animal has an impaired ability to hear sounds in 
specific frequency ranges (Kryter 1985). Physical damage to a mammal's 
hearing apparatus can occur if it is exposed to sound impulses that 
have very high peak pressures, especially if they have very short rise 
times. (Rise time is the interval required for sound pressure to 
increase from the baseline pressure to peak pressure.)
    There is no specific evidence that exposure to pulses of airgun 
sound can cause PTS in any marine mammal, even with large arrays of 
airguns. However, given the likelihood that some mammals close to an 
airgun array might incur at least mild TTS (see above), there has been 
further speculation about the possibility that some individuals 
occurring very close to airguns might incur PTS (e.g., Richardson et 
al. 1995; Gedamke et al. 2008). Single or occasional occurrences of 
mild TTS are not indicative of permanent auditory damage, but repeated 
or (in some cases) single exposures to a level well above that causing 
TTS onset might elicit PTS.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals, but are assumed to be similar to those in humans and 
other terrestrial mammals (Southall et al. 2007). Based on data from 
terrestrial mammals, a precautionary assumption is that the PTS 
threshold for impulse sounds (such as airgun pulses as received close 
to the source) is at least 6 dB higher than the TTS threshold on a 
peak-pressure basis, and probably > 6 dB higher (Southall et al. 2007). 
The low-to-moderate levels of TTS that have been induced in captive 
odontocetes and pinnipeds during controlled studies of TTS have been 
confirmed to be temporary, with no measurable residual PTS (Kastak et 
al. 1999; Schlundt et al. 2000; Finneran et al. 2002; 2005; Nachtigall 
et al. 2003; 2004). However, very prolonged exposure to sound strong 
enough to elicit TTS, or shorter-term exposure to sound levels well 
above the TTS threshold, can cause PTS, at least in terrestrial mammals 
(Kryter 1985). In terrestrial mammals, the received sound level from a 
single non-impulsive sound exposure must be far above the TTS threshold 
for any risk of permanent hearing damage (Kryter 1994; Richardson et 
al. 1995; Southall et al. 2007). However, there is special concern 
about strong sounds whose pulses have very rapid rise times. In 
terrestrial mammals, there are situations when pulses with rapid rise 
times (e.g., from explosions) can result in PTS even though their peak 
levels are only a few dB higher than the level causing slight TTS. The 
rise time of airgun pulses is fast, but not as fast as that of an 
explosion.
    Some factors that contribute to onset of PTS, at least in 
terrestrial mammals, are as follows:
     Exposure to single very intense sound,
     Fast rise time from baseline to peak pressure,
     Repetitive exposure to intense sounds that individually 
cause TTS but not PTS, and
     Recurrent ear infections or (in captive animals) exposure 
to certain drugs.
    Cavanagh (2000) reviewed the thresholds used to define TTS and PTS. 
Based on this review and SACLANT (1998), it is reasonable to assume 
that PTS might occur at a received sound level 20 dB or more above that 
inducing mild TTS. However, for PTS to occur at a received level only 
20 dB above the TTS threshold, the animal probably would have to be 
exposed to a strong

[[Page 49795]]

sound for an extended period, or to a strong sound with rather rapid 
rise time.
    More recently, Southall et al. (2007) estimated that received 
levels would need to exceed the TTS threshold by at least 15 dB, on an 
SEL basis, for there to be risk of PTS. Thus, for cetaceans exposed to 
a sequence of sound pulses, they estimate that the PTS threshold might 
be an M-weighted SEL (for the sequence of received pulses) of ~198 dB 
re 1 [mu]Pa\2\-s. Additional assumptions had to be made to derive a 
corresponding estimate for pinnipeds, as the only available data on TTS 
thresholds in pinnipeds pertained to nonimpulse sound (see above). 
Southall et al. (2007) estimated that the PTS threshold could be a 
cumulative SEL of ~186 dB re 1 [mu]Pa\2\-s in the case of a harbor seal 
exposed to impulse sound. The PTS threshold for the California sea lion 
and northern elephant seal would probably be higher given the higher 
TTS thresholds in those species. Southall et al. (2007) also note that, 
regardless of the SEL, there is concern about the possibility of PTS if 
a cetacean or pinniped received one or more pulses with peak pressure 
exceeding 230 or 218 dB re 1 [mu]Pa, respectively. Thus, PTS might be 
expected upon exposure of cetaceans to either SEL >= 198 dB re 1 
[mu]Pa2-s or peak pressure >= 230 dB re 1 [mu]Pa. Corresponding 
proposed dual criteria for pinnipeds (at least harbor seals) are >= 186 
dB SEL and >= 218 dB peak pressure (Southall et al. 2007). These 
estimates are all first approximations, given the limited underlying 
data, assumptions, species differences, and evidence that the ``equal 
energy'' model may not be entirely correct.
    Sound impulse duration, peak amplitude, rise time, number of 
pulses, and inter-pulse interval are the main factors thought to 
determine the onset and extent of PTS. Ketten (1994) has noted that the 
criteria for differentiating the sound pressure levels that result in 
PTS (or TTS) are location and species specific. PTS effects may also be 
influenced strongly by the health of the receiver's ear.
    As described above for TTS, in estimating the amount of sound 
energy required to elicit the onset of TTS (and PTS), it is assumed 
that the auditory effect of a given cumulative SEL from a series of 
pulses is the same as if that amount of sound energy were received as a 
single strong sound. There are no data from marine mammals concerning 
the occurrence or magnitude of a potential partial recovery effect 
between pulses. In deriving the estimates of PTS (and TTS) thresholds 
quoted here, Southall et al. (2007) made the precautionary assumption 
that no recovery would occur between pulses.
    It is unlikely that an odontocete would remain close enough to a 
large airgun array for sufficiently long to incur PTS. There is some 
concern about bowriding odontocetes, but for animals at or near the 
surface, auditory effects are reduced by Lloyd's mirror and surface 
release effects. The presence of the vessel between the airgun array 
and bow-riding odontocetes could also, in some but probably not all 
cases, reduce the levels received by bow-riding animals (e.g., Gabriele 
and Kipple 2009). The TTS (and thus PTS) thresholds of baleen whales 
are unknown but, as an interim measure, assumed to be no lower than 
those of odontocetes. Also, baleen whales generally avoid the immediate 
area around operating seismic vessels, so it is unlikely that a baleen 
whale could incur PTS from exposure to airgun pulses. The TTS (and thus 
PTS) thresholds of some pinnipeds (e.g., harbor seal) as well as the 
harbor porpoise may be lower (Kastak et al. 2005; Southall et al. 2007; 
Lucke et al. 2009). If so, TTS and potentially PTS may extend to a 
somewhat greater distance for those animals. Again, Lloyd's mirror and 
surface release effects will ameliorate the effects for animals at or 
near the surface.
(5) Non-Auditory Physical Effects
    Non-auditory physical effects might occur in marine mammals exposed 
to strong underwater pulsed sound. Possible types of non-auditory 
physiological effects or injuries that theoretically might occur in 
mammals close to a strong sound source include stress, neurological 
effects, bubble formation, and other types of organ or tissue damage. 
Some marine mammal species (i.e., beaked whales) may be especially 
susceptible to injury and/or stranding when exposed to intense sounds. 
However, there is no definitive evidence that any of these effects 
occur even for marine mammals in close proximity to large arrays of 
airguns, and beaked whales do not occur in the proposed project area. 
In addition, marine mammals that show behavioral avoidance of seismic 
vessels, including most baleen whales, some odontocetes (including 
belugas), and some pinnipeds, are especially unlikely to incur non-
auditory impairment or other physical effects.
    Therefore, it is unlikely that such effects would occur during 
Statoil's proposed surveys given the brief duration of exposure and the 
planned monitoring and mitigation measures described later in this 
document.
    Additional non-auditory effects, while not direct physical impacts, 
include elevated levels of stress response (Wright et al. 2007; Wright 
and Highfill 2007). Although not many studies have been done on noise-
induced stress in marine mammals, extrapolation of information 
regarding stress responses in other species seems appropriate because 
the responses are highly consistent among all species in which they 
have been examined to date (Wright et al. 2007). Therefore, it is 
reasonable to conclude that noise acts as a stressor to marine mammals. 
Furthermore, given that marine mammals will likely respond in a manner 
consistent with other species studied, repeated and prolonged exposures 
to stressors (including or induced by noise) will be problematic for 
marine mammals of all ages. Wright et al. (2007) state that a range of 
issues may arise from the extended stress response including, but not 
limited to, suppression of reproduction (physiologically and 
behaviorally), accelerated aging and sickness-like symptoms.
(6) Stranding and Mortality
    Marine mammals close to underwater detonations of high explosive 
can be killed or severely injured, and the auditory organs are 
especially susceptible to injury (Ketten et al. 1993; Ketten 1995). 
Airgun pulses are less energetic and their peak amplitudes have slower 
rise times, while stranding and mortality events would include other 
energy sources (acoustical or shock wave) far beyond just seismic 
airguns. To date, there is no evidence that serious injury, death, or 
stranding by marine mammals can occur from exposure to airgun pulses, 
even in the case of large airgun arrays.
    However, in numerous past IHA notices for seismic surveys, 
commenters have referenced two stranding events allegedly associated 
with seismic activities, one off Baja California and a second off 
Brazil. NMFS has addressed this concern several times, and, without new 
information, does not believe that this issue warrants further 
discussion. For information relevant to strandings of marine mammals, 
readers are encouraged to review NMFS' response to comments on this 
matter found in 69 FR 74906 (December 14, 2004), 71 FR 43112 (July 31, 
2006), 71 FR 50027 (August 24, 2006), and 71 FR 49418 (August 23, 
2006). In addition, a May-June 2008, stranding of 100-200 melon-headed 
whales (Peponocephala electra) off Madagascar that appears to be 
associated with seismic surveys is

[[Page 49796]]

currently under investigation (IWC 2009).
    It should be noted that strandings related to sound exposure have 
not been recorded for marine mammal species in the Beaufort and Chukchi 
seas. NMFS notes that in the Beaufort Sea, aerial surveys have been 
conducted by MMS and 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 and none 
have been reported by North Slope Borough inhabitants. In addition, 
there are very few instances demonstrating that seismic surveys in 
general have been linked to marine mammal strandings, other than those 
mentioned above. As a result, NMFS does not expect any marine mammals 
will incur serious injury or mortality in the Arctic Ocean or strand as 
a result of proposed seismic survey.

Vessel Sounds

    In addition to the noise generated from seismic airguns and active 
sonar systems, various types of vessels will be used in the operations, 
including source vessels and support vessels. Sounds from boats and 
vessels have been reported extensively (Greene and Moore 1995; 
Blackwell and Greene 2002; 2005; 2006). Numerous measurements of 
underwater vessel sound have been performed in support of recent 
industry activity in the Chukchi and Beaufort Seas. Results of these 
measurements have been reported in various 90-day and comprehensive 
reports since 2007 (e.g., Aerts et al. 2008; Hauser et al. 2008; 
Brueggeman 2009; Ireland et al. 2009). For example, Garner and Hannay 
(2009) estimated sound pressure levels of 100 dB at distances ranging 
from approximately 1.5 to 2.3 mi (2.4 to 3.7 km) from various types of 
barges. MacDonald et al. (2008) estimated higher underwater SPLs from 
the seismic vessel Gilavar of 120 dB at approximately 13 mi (21 km) 
from the source, although the sound level was only 150 dB at 85 ft (26 
m) from the vessel. Compared to airgun pulses, underwater sound from 
vessels is generally at relatively low frequencies.
    The primary sources of sounds from all vessel classes are propeller 
cavitation, propeller singing, and propulsion or other machinery. 
Propeller cavitation is usually the dominant noise source for vessels 
(Ross 1976). Propeller cavitation and singing are produced outside the 
hull, whereas propulsion or other machinery noise originates inside the 
hull. There are additional sounds produced by vessel activity, such as 
pumps, generators, flow noise from water passing over the hull, and 
bubbles breaking in the wake. Icebreakers contribute greater sound 
levels during ice-breaking activities than ships of similar size during 
normal operation in open water (Richardson et al. 1995). This higher 
sound production results from the greater amount of power and propeller 
cavitation required when operating in thick ice. Source levels from 
various vessels would be empirically measured before the start of 
marine surveys.

Anticipated Effects on Habitat

    The primary potential impacts to marine mammals and other marine 
species are associated with elevated sound levels produced by airguns 
and other active acoustic sources. However, other potential impacts to 
the surrounding habitat from physical disturbance are also possible.

Potential Impacts on Prey Species

    With regard to fish as a prey source for cetaceans and pinnipeds, 
fish are known to hear and react to sounds and to use sound to 
communicate (Tavolga et al. 1981) and possibly avoid predators (Wilson 
and Dill 2002). Experiments have shown that fish can sense both the 
strength and direction of sound (Hawkins, 1981). Primary factors 
determining whether a fish can sense a sound signal, and potentially 
react to it, are the frequency of the signal and the strength of the 
signal in relation to the natural background noise level.
    The level of sound at which a fish will react or alter its behavior 
is usually well above the detection level. Fish have been found to 
react to sounds when the sound level increased to about 20 dB above the 
detection level of 120 dB (Ona 1988); however, the response threshold 
can depend on the time of year and the fish's physiological condition 
(Engas et al. 1993). In general, fish react more strongly to pulses of 
sound rather than a continuous signal (Blaxter et al. 1981), and a 
quicker alarm response is elicited when the sound signal intensity 
rises rapidly compared to sound rising more slowly to the same level.
    Investigations of fish behavior in relation to vessel noise (Olsen 
et al. 1983; Ona 1988; Ona and Godo 1990) have shown that fish react 
when the sound from the engines and propeller exceeds a certain level. 
Avoidance reactions have been observed in fish such as cod and herring 
when vessels approached close enough that received sound levels are 110 
dB to 130 dB (Nakken 1992; Olsen 1979; Ona and Godo 1990; Ona and 
Toresen 1988). However, other researchers have found that fish such as 
polar cod, herring, and capeline are often attracted to vessels 
(apparently by the noise) and swim toward the vessel (Rostad et al. 
2006). Typical sound source levels of vessel noise in the audible range 
for fish are 150 dB to 170 dB (Richardson et al. 1995).
    Some mysticetes, including bowhead whales, feed on concentrations 
of zooplankton. Some feeding bowhead whales may occur in the Alaskan 
Beaufort Sea in July and August, and others feed intermittently during 
their westward migration in September and October (Richardson and 
Thomson [eds.] 2002; Lowry et al. 2004). Reactions of zooplanktoners to 
sound are, for the most part, not known. Their abilities to move 
significant distances are limited or nil, depending on the type of 
animal. A reaction by zooplankton to sounds produced by the marine 
survey program would only be relevant to whales if it caused 
concentrations of zooplankton to scatter. Pressure changes of 
sufficient magnitude to cause that type of reaction would probably 
occur only near the airgun source, which is expected to be a very small 
area. Impacts on zooplankton behavior are predicted to be negligible, 
and that would translate into negligible impacts on feeding mysticetes.

Estimated Take by Incidental 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]. Only take by Level B behavioral 
harassment is anticipated as a result of the proposed open water 
seismic survey program. Anticipated impacts to marine mammals are 
associated with noise propagation from the seismic airgun(s) used in 
the seismic survey.
    The full suite of potential impacts to marine mammals was described 
in detail in the ``Potential Effects of the Specified Activity on 
Marine Mammals'' section found earlier in this document. The potential 
effects of sound from the proposed open water marine survey programs 
might include one or more of the following: Tolerance; masking of 
natural sounds; behavioral disturbance; non-auditory physical effects; 
and, at

[[Page 49797]]

least in theory, temporary or permanent hearing impairment (Richardson 
et al. 1995). As discussed earlier in this document, the most common 
impact will likely be from behavioral disturbance, including avoidance 
of the ensonified area or changes in speed, direction, and/or diving 
profile of the animal. For reasons discussed previously in this 
document, hearing impairment (TTS and PTS) are highly unlikely to occur 
based on the proposed mitigation and monitoring measures that would 
preclude marine mammals being exposed to noise levels high enough to 
cause hearing impairment.
    For impulse sounds, such as those produced by airgun(s) used in the 
seismic survey, NMFS uses the 160 dB re 1 [mu]Pa (rms) isopleth to 
indicate the onset of Level B harassment. Statoil provided calculations 
for the 160-dB isopleths produced by these active acoustic sources and 
then used those isopleths to estimate takes by harassment. NMFS used 
the calculations to make the necessary MMPA preliminary findings. 
Statoil provided a full description of the methodology used to estimate 
takes by harassment in its IHA application (see ADDRESSES), which is 
also provided in the following sections.
    Statoil has requested an authorization to take 13 marine mammal 
species by Level B harassment. These 13 marine mammal species are: 
Beluga whale (Delphinapterus leucas), narwhal (Monodon monoceros), 
killer whale (Orcinus orca), harbor porpoise (Phocoena phocoena), 
bowhead whale (Balaena mysticetus), gray whale (Eschrichtius robustus), 
humpback whale (Megaptera novaeangliae), minke whale (Balaenoptera 
acutorostrata), fin whale (B. physalus), bearded seal (Erignathus 
barbatus), ringed seal (Phoca hispida), spotted seal (P. largha), and 
ribbon seal (Histriophoca fasciata). However, NMFS believes that 
narwhals are not likely to occur in the proposed survey area during the 
time of the proposed marine seismic survey. Therefore, NMFS believes 
that only the other 12 marine mammal species could potentially be taken 
by Level B behavioral harassment as a result of the proposed marine 
surveys.

Basis for Estimating ``Take by Harassment''

    As stated previously, it is current NMFS policy to estimate take by 
Level B harassment for impulse sounds at a received level of 160 dB re 
1[mu]Pa (rms). However, not all animals react to sounds at this low 
level, and many will not show strong reactions (and in some cases any 
reaction) until sounds are much stronger. Southall et al. (2007) 
provide a severity scale for ranking observed behavioral responses of 
both free-ranging marine mammals and laboratory subjects to various 
types of anthropogenic sound (see Table 4 in Southall et al. (2007)). 
Tables 7, 9, and 11 in Southall et al. (2007) outline the numbers of 
low-frequency cetaceans, mid-frequency cetaceans, and pinnipeds in 
water, respectively, reported as having behavioral responses to multi-
pulses in 10-dB received level increments. These tables illustrate that 
the more severe reactions did not occur until sounds were much higher 
than 160 dB re 1[mu]Pa (rms).
    As described earlier in the document, the proposed open water 
marine seismic survey would use two airgun arrays with a total 
discharge volume of 3,000 in \3\. The modeled 160 dB zone of influence 
reaches to 13 km from the airgun source. The estimated number of 
animals potentially harassed was calculated by multiplying the expected 
densities (in number/km\2\) by the anticipated area ensonified by 
levels of >=160 dB re 1[mu]Pa. Estimates of the number of animals 
potentially impacted were conducted separately for the 3D survey area 
and the 2D survey lines. For the 3D survey area, the anticipated area 
ensonified by sound levels of >=160 dB was calculated as an area 
encompassing a 8.1 mi (13 km) radius extending from each point of the 
survey area perimeter (hereafter called the 160 dB exposed survey 
area). This approach was taken because closely spaced survey lines and 
large cross-track distances of the >=160 dB radii result in repeated 
exposure of the same area of water. Excessive amounts of repeated 
exposure leads to an overestimation of the number of animals 
potentially exposed. For the 2D survey lines the area ensonified by 
sound levels of >=160 dB was calculated as the total line kilometers 
multiplied by 2 times the 8.1 mi (13 km) >=160 dB safety radius. The 
following subsections describe in more detail the data and methods used 
in deriving the estimated number of animals potentially ``taken by 
harassment'' during the proposed survey. It provides information on the 
expected marine mammal densities, estimated distances to received 
levels of 190, 180, 160, and 120 dB re 1[mu]Pa and the calculation of 
anticipated areas ensonified by levels of >=160 dB.
    It is important to understand that not all published results from 
visual observations have applied correction factors that account for 
detectability and availability bias. Detectability bias, quantified in 
part by f(0), is associated with diminishing sightability with 
increasing lateral distance from the survey trackline. Availability 
bias [g(0)] refers to the fact that not all animals are at the surface 
and that there is therefore <100% probability of sighting an animal 
that is present along the survey trackline. Some sources below included 
correction factors in the reported densities (e.g., ringed seals in 
Bengtson et al. 2005) and the best available correction factors were 
applied to reported results when they had not already been included 
(e.g., Moore et al. 2000b).
(1) Cetaceans
    Eight species of cetaceans are known to occur in the Chukchi Sea 
area of the proposed Statoil project. Only four of these (bowhead, 
beluga, and gray whales, and harbor porpoise) are likely to be 
encountered during the proposed survey activities. Three of the eight 
species (bowhead, fin, and humpback whales) are listed as endangered 
under the ESA. Of these, only the bowhead is likely to be found within 
the survey area.
    Beluga Whales--Summer densities of beluga in offshore waters are 
expected to be low. Aerial surveys have recorded few belugas in the 
offshore Chukchi Sea during the summer months (Moore et al. 2000b). 
Aerial surveys of the Chukchi Sea in 2008-2009 flown by the NMML as 
part of the Chukchi Offshore Monitoring in Drilling Area project 
(COMIDA) have only reported 5 beluga sightings during > 8,700 mi (> 
14,000 km) of on-transect effort, only 2 of which were offshore (COMIDA 
2009). Additionally, only one beluga sighting was recorded during > 
37,904 mi (> 61,000 km) of visual effort during good visibility 
conditions from industry vessels operating in the Chukchi Sea in July-
August of 2006-2008 (Haley et al. 2009b). If belugas are present during 
the summer, they are more likely to occur in or near the ice edge or 
close to shore during their northward migration. Expected densities 
were calculated from data in Moore et al. (2000b). Data from Moore et 
al. (2000b: Figure 6 and Table 6) used as the average open-water 
density estimate included two on-transect beluga sightings during 6,639 
mi (10,684 km) of on-transect effort in the Chukchi Sea during summer. 
A mean group size of 7.1 (CV = 1.7) was calculated from 10 Chukchi Sea 
summer sightings present in the BWASP database. A f(0) value of 2.841 
and g(0) value of 0.58 from Harwood et al. (1996) were also used in the 
calculation. The CV associated with group size was used to select an 
inflation factor of 2 to estimate the maximum density that may occur in 
both open-water and ice-margin habitats. Specific data on the

[[Page 49798]]

relative abundance of beluga in open-water versus ice-margin habitat 
during the summer in the Chukchi Sea is not available. However, Moore 
et al. (2000b) reported higher than expected beluga sighting rates in 
open-water during fall surveys in the Beaufort and Chukchi Seas. This 
would suggest that densities near ice may actually be lower than open 
water, but belugas are commonly associated with ice, so an inflation 
factor of only 2 (instead of 4) was used to estimate the average ice-
margin density from the open-water density. Based on the very low 
densities observed from vessels operating in the Chukchi Sea during 
non-seismic periods and locations in July-August of 2006-2008 (0.0001/
km\2\; Haley et al. 2009b), the densities shown in Table 1 are likely 
biased high.
    In the fall, beluga whale densities in the Chukchi Sea are expected 
to be somewhat higher than in the summer because individuals of the 
eastern Chukchi Sea stock and the Beaufort Sea stock will be migrating 
south to their wintering grounds in the Bering Sea (Angliss and Allen 
2009). Consistent with this, the number of on-effort beluga sightings 
reported during COMIDA flights in September-October of 2008-2009 was 
over 3 times more than during July-August with a very similar amount of 
on-transect effort (COMIDA 2009). However, there were no beluga 
sightings reported during >11,185 mi (>18,000 km) of vessel based 
effort in good visibility conditions during 2006-2008 industry 
operations in the Chukchi Sea. Densities derived from survey results in 
the northern Chukchi Sea in Moore et al. (2000b) were used as the 
average density for open-water and ice-margin fall season estimates 
(see Table 2). Data from Moore et al. (2000b: Table 8) used in the 
average open-water density estimate included 123 beluga sightings and 
27,559 mi (44,352 km) of on-transect effort in water depths 118-164 ft 
(36-50 m). A mean group size of 2.39 (CV = 0.92) came from the average 
group size of 82 Chukchi Sea fall sightings in waters 115-164 ft (35-50 
m) deep present in the BWASP database. A f(0) value of 2.841 and g(0) 
value of 0.58 from Harwood et al. (1996) were used in the calculation. 
The CV associated with group size was used to select an inflation 
factor of 2 to estimate the maximum density that may occur in both 
open-water and ice-margin habitats. Moore et al. (2000b) reported 
higher than expected beluga sighting rates in open-water during fall 
surveys in the Beaufort and Chukchi seas, so an inflation value of only 
2 was used to estimate the average ice-margin density from the open-
water density. There were no beluga sightings from vessels operating in 
the Chukchi Sea during non-seismic periods in September-October of 
2006-2008 (Haley et al. 2009b).

   Table 1--Expected Densities of Cetaceans and Seals in Areas of the
 Chukchi Sea, Alaska, During the Planned Summer (July-August) Period of
                       the Seismic Survey Program
------------------------------------------------------------------------
                                                 Nearshore    Ice margin
                                               -------------------------
                                                  Average      Average
                    Species                       density      density
                                                (/  (/
                                                   km\2\)       km\2\)
------------------------------------------------------------------------
Beluga whale..................................       0.0033       0.0162
Killer whale..................................       0.0001       0.0001
Harbor porpoise...............................       0.0011       0.0011
Bowhead whale.................................       0.0018       0.0018
Fin whale.....................................       0.0001       0.0001
Gray whale....................................       0.0081       0.0081
Humpback whale................................       0.0001       0.0001
Minke whale...................................       0.0001       0.0001
Bearded seal..................................       0.0107       0.0142
Ribbon seal...................................       0.0003       0.0003
Ringed seal...................................       0.3668       0.4891
Spotted seal..................................       0.0073       0.0098
------------------------------------------------------------------------


   Table 2--Expected Densities of Cetaceans and Seals in Areas of the
 Chukchi Sea, Alaska, During the Planned Fall (September-October) Period
                      of the Seismic Survey Program
------------------------------------------------------------------------
                                                 Nearshore    Ice margin
                                               -------------------------
                                                  Average      Average
                    Species                       density      density
                                                (/  (/
                                                   km\2\)       km\2\)
------------------------------------------------------------------------
Beluga whale..................................       0.0162       0.0324
Killer whale..................................       0.0001       0.0001
Harbor porpoise...............................       0.0010       0.0010
Bowhead whale.................................       0.0174       0.0348
Fin whale.....................................       0.0001       0.0001
Gray whale....................................       0.0062       0.0062
Humpback whale................................       0.0001       0.0001
Minke whale...................................       0.0001       0.0001
Bearded seal..................................       0.0107       0.0142
Ribbon seal...................................       0.0003       0.0003
Ringed seal...................................       0.2458       0.3277
Spotted seal..................................       0.0049       0.0065
------------------------------------------------------------------------

    Bowhead Whales--By July, most bowhead whales are northeast of the 
Chukchi Sea, within or migrating toward their summer feeding grounds in 
the eastern Beaufort Sea. No bowheads were reported during 6,639 mi 
(10,684 km) of on-transect effort in the Chukchi Sea by Moore et al. 
(2000b). Aerial surveys in 2008-2009 by the NMML as part of the COMIDA 
project reported four sightings during > 8,699 mi (>14,000 km) of on-
transect effort. Two of the four sightings were offshore, both of which 
occurred near the end of August. Bowhead whales were also rarely 
reported in July-August of 2006-2008 during aerial surveys of the 
Chukchi Sea coast (Thomas et al. 2009). This is consistent with 
movements of tagged whales (see ADFG 2009; Quakenbush 2009), all of 
which moved through the Chukchi Sea by early May 2009, and tended to 
travel relatively close to shore, especially in the northern Chukchi 
Sea.
    The estimate of bowhead whale density in the Chukchi Sea was 
calculated by assuming that there was one bowhead sighting during the 
6,639 mi (10,684 km) survey effort in the Chukchi Sea during the 
summer, although no bowheads were actually observed (Moore et al. 
2000b). The more recent COMIDA data were not used because the NMML has 
not released a final report summarizing the data. Only two sightings 
are present in the BWASP database during July and August in the Chukchi 
Sea, both of which were of individual whales. The mean group size from 
combined July-August sightings in the BWASP, COMIDA, and 2006-2008 
industry database is 1.33 (CV= 0.58). This value, along with a f(0) 
value of 2 and a g(0) value of 0.07, both from Thomas et al. (2002) 
were used to estimate a summer density of bowhead whales. The CV of 
group size and standard errors reported in Thomas et al. (2002) for 
f(0) and g(0) correction factors suggest that an inflation factor of 2 
is appropriate for deriving a maximum density from the average density. 
Bowheads are not expected to be encountered in higher densities near 
ice in the summer (Moore et al. 2000b), so the same density estimates 
are used for open-water and ice-margin habitats. Densities from vessel 
based surveys in the Chukchi Sea during non-seismic periods and 
locations in July-August of 2006-2008 (Haley et al. 2009b) ranged from 
0.0001/km\2\ to 0.0005/km\2\ with a maximum 95 percent confidence 
interval (CI) of 0.0019 km\2\. This suggests that the densities used in 
the calculations and shown in Table 1 might be somewhat higher than 
expected to be observed from vessels near the area of planned 
operations.
    During the fall, bowhead whales migrate west and south from their 
summer feeding grounds in the Beaufort Sea and Amundsen Gulf to their 
wintering grounds in the Bering Sea. During this fall migration 
bowheads are more likely to be encountered in the Chukchi Sea. Moore et 
al. (2000b: Table 8) reported 34 bowhead sightings during 27,560 mi 
(44,354 km) of on-transect

[[Page 49799]]

survey effort in the Chukchi Sea during September-October. Thomas et 
al. (2009) also reported increased sightings on coastal surveys of the 
Chukchi Sea during September and October of 2006-2008. Aerial surveys 
in 2008-2009 (COMIDA 2009) reported 20 bowhead sightings during 8,803 
mi (14,167 km) of on-transect effort, eight of which were offshore. GPS 
tagging of bowheads show that migration routes through the Chukchi Sea 
are more variable than through the Beaufort Sea (ADFG 2009; Quakenbush 
2009). Some of the routes taken by bowheads remain well north or south 
of the planned survey activities while others have passed near to or 
through the area. Kernel densities estimated from GPS locations of 
whales suggest that bowheads do not spend much time (e.g., feeding or 
resting) in the north-central Chukchi Sea near the area of planned 
activities (ADFG 2009). The mean group size from September-October 
Chukchi Sea bowhead sightings in the BWASP database is 1.59 (CV=1.08). 
This is slightly below the mean group size of 1.85 from all the 
preliminary COMIDA sightings during the same months, but above the 
value of 1.13 from only on-effort COMIDA sightings (COMIDA 2009). The 
same f(0) and g(0) values that were used for the summer estimates above 
were used for the fall estimates. As with the summer estimates, an 
inflation factor of 2 was used to estimate the maximum density from the 
average density in both habitat types. Moore et al. (2000b) found that 
bowheads were detected more often than expected in association with ice 
in the Chukchi Sea in September-October, so a density of twice the 
average open-water density was used as the average ice-margin density. 
Densities from vessel based surveys in the Chukchi Sea during non-
seismic periods and locations in September-October of 2006-2008 (Haley 
et al. 2009b) ranged from 0.0001/km\2\ to 0.0050/km\2\ with a maximum 
95 percent CI of 0.0480 km\2\. This suggests the densities used in the 
calculations and shown in Table 2 are somewhat higher than are likely 
to be observed from vessels near the area of planned operations.
    Gray Whales--The average open-water summer density was calculated 
from effort and sightings in Moore et al. (2000b: Table 6) for water 
depths 118-164 ft (36-50 m) including 4 sightings during 3,901 mi 
(6,278 km) of on-transect effort. An average group size of 3.11 
(CV=0.97) was calculated from all July-August Chukchi Sea gray whale 
sightings in the BWASP database and used in the summer density 
estimate. This value was higher than the average group size in the 
preliminary COMIDA data (1.71; COMIDA 2009) and from coastal aerial 
surveys in 2006-2008 (1.27; Thomas et al. 2009). Correction factors 
f(0) = 2.49 (Forney and Barlow 1998) and g(0) = 0.30 (Forney and Barlow 
1998; Mallonee 1991) were also used in the density calculation. Since 
the group size used in the average density estimate was relatively high 
compared to other data sources and the CV was near to one, an inflation 
factor of 2 was used to estimate the maximum densities from average 
densities in both habitat types. Gray whales are not commonly 
associated with sea ice, but may occur close to sea ice, so the 
densities for open-water habitat were also used for ice-margin habitat. 
Densities from vessel based surveys in the Chukchi Sea during non-
seismic periods and locations in July-August of 2006-2008 (Haley et al. 
2009b) ranged from 0.0009/km\2\ to 0.0034/km\2\ with a maximum 95 
percent CI of 0.0146 km\2\. This suggests that the densities used in 
the calculations and shown in Table 1 are somewhat higher than are 
expected to be observed from vessels near the area of planned 
operations.
    Gray whale densities are expected to be much higher in the summer 
months than during the fall when most whales start their southbound 
migration. Moore et al. (2000b) found that the distribution of gray 
whales was more widely dispersed through the northern Chukchi Sea and 
limited to nearshore areas where most whales were observed in water 
less than 115 ft (35 m) deep. With similar amounts of on-transect 
effort between summer and fall aerial surveys in 2008-2009, gray whale 
sightings were three times higher in July-August than in September-
October, and five times higher taking into account all effort and 
sightings (COMIDA 2009). Thomas et al. (2009) also reported decreased 
sighting rates of gray whales in the fall.
    The on-transect effort and associated gray whale sightings (27 
sightings during 44,352 km of on-transect effort) in water depth of 
118-164 ft (36-50 m) during autumn (Moore et al. 2000b; 12) was used as 
the average density estimate for the Chukchi Sea during the fall 
period. A group size value of 2.49 (CV=1.37) calculated from the BWASP 
database was used in the density calculation, along with the same f(0) 
and g(0) values described above. The group size value of 2.49 was again 
higher than the average group size calculated from preliminary COMIDA 
data (1.24; COMIDA 2009) and as reported from coastal aerial surveys in 
2006-2008 (1.12; Thomas et al. 2009). Densities from vessel based 
surveys in the Chukchi Sea during non-seismic periods and locations in 
September-October of 2006-2008 (Haley et al. 2009b) ranged from 0.0011/
km\2\ to 0.0024/km\2\ with a maximum 95 percent CI of 0.0183 km\2\. 
This suggests the densities used in the calculations and shown in Table 
2 are somewhat higher than are likely to be observed from vessels near 
the area of planned operations.
    Harbor Porpoise--Harbor Porpoise densities were estimated from 
industry data collected during 2006-2008 activities in the Chukchi Sea. 
Prior to 2006, no reliable estimates were available for the Chukchi Sea 
and harbor porpoise presence was expected to be very low and limited to 
nearshore regions. For this reason, the data collected from industry 
vessels was considered to be the best available data. Observers on 
industry vessels in 2006-2008, however, recorded sightings throughout 
the Chukchi Sea during the summer and early fall months. Density 
estimates from 2006-2008 observations during non-seismic periods and 
locations in July-August ranged from 0.0009/km\2\ to 0.0016/km\2\ with 
a maximum 95 percent CI of 0.0016/km\2\ (Haley et al. 2009b). The 
median value from the summer season of those three years (0.0011/km\2\) 
was used as the average open-water density estimate while the high 
value (0.0016/km\2\) was used as the maximum estimate (Table 1). Harbor 
porpoise are not expected to be present in higher numbers near ice, so 
the open-water densities were used for ice-margin habitat in both 
seasons. Harbor porpoise densities recorded during industry operations 
in the fall months of 2006-2008 were slightly lower and ranged from 
0.0002/km\2\ to 0.0013/km\2\ with a maximum 95 percent CI of 0.0044/
km\2\. The median value (0.0010/km\2\) was again used as the average 
density estimate and the high value (0.0013/km\2\) was used as the 
maximum estimate (Table 2).
    Other Cetaceans--The remaining four cetacean species that could be 
encountered in the Chukchi Sea during Statoil's planned seismic survey 
include the humpback whale, killer whale, minke whale, and fin whale. 
Although there is evidence of the occasional occurrence of these 
animals in the Chukchi Sea, it is unlikely that more than a few 
individuals will be encountered during the proposed activities. George 
and Suydam (1998) reported killer whales, Brueggeman et al. (1990) and 
Haley et al. (2009b) reported minke whale, and COMIDA (2009) and Haley 
et al. (2009b) reported fin whales off of Ledyard Bay in the Chukchi 
Sea.

[[Page 49800]]

(2) Pinnipeds
    Four species of pinnipeds may be encountered in the Chukchi Sea: 
Ringed seal, bearded seal, spotted seal, and ribbon seal. Each of these 
species, except the spotted seal, is associated with both the ice 
margin and the nearshore area. The ice margin is considered preferred 
habitat (as compared to the nearshore areas) during most seasons.
    Ringed and Bearded Seals--Ringed seal and bearded seal average 
summer ice-margin densities (Table 1) were available in Bengtson et al. 
(2005) from spring surveys in the offshore pack ice zone (zone 12P) of 
the northern Chukchi Sea. However, corrections for bearded seal 
availability, g(0), based on haulout and diving patterns were not 
available. Densities of ringed and bearded seals in open water are 
expected to be somewhat lower in the summer when preferred pack ice 
habitat may still be present in the Chukchi Sea. Average and maximum 
open-water densities have been estimated as \3/4\ of the ice margin 
densities during the summer for both species. The fall density of 
ringed seals in the offshore Chukchi Sea has been estimated as \2/3\ 
the summer densities because ringed seals begin to reoccupy nearshore 
fast ice areas as it forms in the fall. Bearded seals may begin to 
leave the Chukchi Sea in the fall, but less is known about their 
movement patterns so fall densities were left unchanged from summer 
densities. For comparison, the ringed seal density estimates calculated 
from data collected during summer 2006-2008 industry operations ranged 
from 0.0082/km\2\ to 0.0221/km\2\ with a maximum 95 percent CI of 
0.0577/km\2\ (Haley et al. 2009b). These estimates are lower than those 
made by Bengtson et al. (2005) which is not surprising given the 
different survey methods and timing.
    Spotted Seal--Little information on spotted seal densities in 
offshore areas of the Chukchi Sea is available. Spotted seals are often 
considered to be predominantly a coastal species except in the spring 
when they may be found in the southern margin of the retreating sea 
ice, before they move to shore. However, satellite tagging has shown 
that they sometimes undertake long excursions into offshore waters 
during summer (Lowry et al. 1994, 1998). Spotted seal densities in the 
summer were estimated by multiplying the ringed seal densities by 0.02. 
This was based on the ratio of the estimated Chukchi populations of the 
two species. Chukchi Sea spotted seal abundance was estimated by 
assuming that 8% of the Alaskan population of spotted seals is present 
in the Chukchi Sea during the summer and fall (Rugh et al. 1997), the 
Alaskan population of spotted seals is 59,214 (Angliss and Allen 2009), 
and that the population of ringed seals in the Alaskan Chukchi Sea is 
>208,000 animals (Bengtson et al. 2005). In the fall, spotted seals 
show increased use of coastal haulouts so densities were estimated to 
be \2/3\ of the summer densities.
    Ribbon Seal--Ribbon seals have been reported in very small numbers 
within the Chukchi Sea by observers on industry vessels (two sightings; 
Haley et al. 2009b). The resulting density estimate of 0.0003/km\2\ was 
used as the average density and a multiplier of 4 was used as the 
estimated maximum density for both seasons and habitat zones.

Potential Number of Takes by Harassment

    This subsection provides estimates of the number of individuals 
potentially exposed to sound levels >=160 dB re 1 [mu]Pa (rms). The 
estimates are based on a consideration of the number of marine mammals 
that might be disturbed (through Level B harassment) by operations in 
the Chukchi Sea and the anticipated area exposed to sound levels of 160 
dB re 1 [mu]Pa (rms).
    As described above, marine mammal density estimates for the Chukchi 
Sea have been derived for two time periods, the summer period (July-
August), and the fall period (September-October). Animal densities 
encountered in the Chukchi Sea during both of these time periods will 
further depend on the habitat zone within which the source vessel is 
operating, i.e., open water or ice margin. The seismic source vessel is 
not an icebreaker and cannot tow survey equipment through pack ice. 
Under this assumption, densities of marine mammals expected to be 
observed near ice margin areas have been applied to 10% of the proposed 
3D survey area and 2D tracklines in both seasons. Densities of marine 
mammals expected to occur in open water areas have been applied to the 
remaining 90% of the 3D survey and 2D tracklines area in both seasons.
    The number of individuals of each species potentially exposed to 
received levels >=160 dB re 1 [mu]Pa (rms) within each season and 
habitat zone was estimated by multiplying
     The anticipated area to be ensonified to the specified 
level in each season and habitat zone to which that density applies, by
     The expected species density.
    The numbers of individuals potentially exposed were then summed for 
each species across the two seasons and habitat zones. Some of the 
animals estimated to be exposed, particularly migrating bowhead whales, 
might show avoidance reactions before being exposed to >=160 dB re 1 
[mu]Pa (rms). Thus, these calculations actually estimate the number of 
individuals potentially exposed to >=160 dB that would occur if there 
were no avoidance of the area ensonified to that level.
(1) 3D Seismic Survey Area
    The size of the proposed 3D seismic survey area is 915 mi\2\ (2,370 
km\2\) and located >100 mi (160 km) offshore. Approximately \1/4\ of 
the area (~234 mi\2\, or ~606 km\2\) is expected to be surveyed in 
August (weather depending). This area, with a 160 dB radius of 8 mi (13 
km) along each point of its perimeter equals a total area of ~1,081 
mi\2\ (~2,799 km\2\). Summer marine mammal densities from Table 1 have 
been applied to this area. The other \3/4\ of the survey area (~687 
mi\2\, or ~1,779 km\2\) is expected to be covered in September-October. 
This area, also with a 160 dB radius of 8 mi (13 km) along each point 
of its perimeter results in a total area of ~1,813 mi\2\ (~4,695 
km\2\). Fall marine mammal densities from Table 2 have been applied to 
this area. Based on these assumptions and those described above, the 
estimates of marine mammals potentially exposed to sounds >=160 dB in 
the Chukchi Sea from seismic data acquisition in the 3D survey area 
were calculated in Table 3.
    For the common species, the requested numbers were calculated as 
described above and based on the average and maximum densities 
reported. For less common species, for which minimum density estimates 
were assumed, the numbers were set to a minimum to allow for chance 
encounters. The mitigation gun (60 in\3\) will be active during turns 
extending about 1.6 mi (2.5 km) outside the 3D survey area. The 
estimated 160 dB radius for the 60 in\3\ mitigation gun is 5,906 ft 
(1,800 m) and therefore falls well within the area expected to be 
exposed to received sound levels of >=160 dB of the 3D survey area.

[[Page 49801]]



Table 3--Summary of the Number of Potential Exposures of Marine Mammals to Received Sound Levels in the Water of
            >= 160 dB During Statoil's Planned Marine Seismic Survey in the Chukchi Sea, Alaska, 2010
----------------------------------------------------------------------------------------------------------------
                                                             Number of          Number of
                                                         exposure to sound  exposure to sound   Total number of
                                                          levels > 160 dB    levels > 160 dB   exposure to sound
                        Species                          re 1 [mu]Pa (rms)  re 1 [mu]Pa (rms)   levels > 160 dB
                                                           by 3D seismic      by 2D seismic    re 1 [mu]Pa (rms)
                                                               survey             survey
----------------------------------------------------------------------------------------------------------------
Beluga whale...........................................                 97                 87                184
Killer whale...........................................                  1                  1                  2
Harbor porpoise........................................                  8                 13                 21
Bowhead whale..........................................                 95                 63                158
Gray whale.............................................                 52                 92                144
Humpback whale.........................................                  1                  1                  2
Fin whale..............................................                  1                  1                  2
Minke whale............................................                  1                  1                  2
Bearded seal...........................................                 82                132                214
Ribbon seal............................................                  2                  4                  6
Ringed seal............................................              2,253              4,234              6,487
Spotted seal...........................................                 45                 85                130
----------------------------------------------------------------------------------------------------------------

(2) 2D Seismic Survey Lines
    Seismic data along the ~420 mi (675 km) of four 2D survey 
tracklines might be acquired with the full airgun array if access to 
the 3D survey area is restricted (e.g., ice conditions), or 3D 
acquisition progress is better than anticipated. Under the assumption 
that these restrictive weather conditions will mainly be an issue in 
the early summer season, 80% of the 2D tracklines are assumed to be 
acquired during August and 20% during the fall. The total area 
potentially exposed to >= 160 dB from these tracklines was calculated 
with the trackline sections outside the 3D survey area. Excluding these 
sections results in a total trackline length of ~285 mi (460 km). With 
a 160 dB radius of ~8 mi (13 km) this results in a total exposed area 
of ~7,432 mi\2\ (11,960 km\2\). Such summer densities were used for 80% 
of the total area (5,945 mi\2\, or 9,568 km\2\) and fall densities for 
the remaining 20% (1,486 mi\2\, or 2,392 km\2\). Following a similar 
approach as for the 3D survey area, numbers of more common marine 
mammal species were calculated based on the average and maximum 
densities and for less common species the numbers were set to a minimum 
to allow for chance encounters. The results of estimates of marine 
mammals potentially exposed to sounds >= 160 dB in the Chukchi Sea from 
seismic data acquisition along the 2D tracklines are presented in Table 
3.

Estimated Take Conclusions

    Cetaceans--Effects on cetaceans are generally expected to be 
restricted to avoidance of an area around the seismic survey and short-
term changes in behavior, falling within the MMPA definition of ``Level 
B harassment''.
    Using the 160 dB criterion, the average estimates of the numbers of 
individual cetaceans exposed to sounds =160 dB re 1 [mu]Pa 
(rms) represent varying proportions of the populations of each species 
in the Beaufort Sea and adjacent waters. For species listed as 
``Endangered'' under the ESA, the estimates include approximately 158 
bowheads. This number is approximately 1.11% of the Bering-Chukchi-
Beaufort population of > 14,247 assuming 3.4% annual population growth 
from the 2001 estimate of > 10,545 animals (Zeh and Punt 2005). For 
other cetaceans that might occur in the vicinity of the marine seismic 
survey in the Chukchi Sea, they also represent a very small proportion 
of their respective populations. The average estimates of the number of 
belugas, killer whales, harbor porpoises, gray whales, fin whales, 
humpback whales, and minke whales that might be exposed to = 
160 dB re 1 [mu]Pa (rms) are 183, 2, 21, 144, 2, 2, and 2. These 
numbers represent 4.95%, 0.62%, 0.04%, 0.81%, 0.03%, 0.21%, and 0.19% 
of these species respective populations in the proposed action area.
    Seals--A few seal species are likely to be encountered in the study 
area, but ringed seal is by far the most abundant in this area. The 
average estimates of the numbers of individuals exposed to sounds at 
received levels = 160 dB re 1 [mu]Pa (rms) during the 
proposed seismic survey are as follows: Ringed seals (6,487), bearded 
seals (215), spotted seals (129), and ribbon seals (6). These numbers 
represent 2.81%, 0.09%, 0.22%, and 0.01% of Alaska stocks of ringed, 
bearded, spotted, and ribbon seals.

Impact on Availability of Affected Species or Stock for Taking for 
Subsistence Uses

Relevant Subsistence Uses

    The disturbance and potential displacement of marine mammals by 
sounds from the proposed marine surveys are the principal concerns 
related to subsistence use of the area. Subsistence remains the basis 
for Alaska Native culture and community. Marine mammals are legally 
hunted in Alaskan waters by coastal Alaska Natives. In rural Alaska, 
subsistence activities are often central to many aspects of human 
existence, including patterns of family life, artistic expression, and 
community religious and celebratory activities. Additionally, the 
animals taken for subsistence provide a significant portion of the food 
that will last the community throughout the year. The main species that 
are hunted include bowhead and beluga whales, ringed, spotted, and 
bearded seals, walruses, and polar bears. (Both the walrus and the 
polar bear are under the USFWS' jurisdiction.) The importance of each 
of these species varies among the communities and is largely based on 
availability.
    Subsistence hunting and fishing continue to be prominent in the 
household economies and social welfare of some Alaskan residents, 
particularly among those living in small, rural villages (Wolfe and 
Walker 1987). Subsistence remains the basis for Alaska Native culture 
and community. In rural Alaska, subsistence activities are often 
central to many aspects of human existence, including patterns of 
family life, artistic expression, and community religious and 
celebratory activities.
    Marine mammals are legally hunted in Alaskan waters by coastal 
Alaska Natives; species hunted include

[[Page 49802]]

bowhead and beluga whales; ringed, spotted, and bearded seals; 
walruses, and polar bears. The importance of each of the various 
species varies among the communities based largely on availability. 
Bowhead whales, belugas, and walruses are the marine mammal species 
primarily harvested during the time of the proposed seismic survey. 
There is little or no bowhead hunting by the community of Point Lay, so 
beluga and walrus hunting are of more importance there. Members of the 
Wainwright community hunt bowhead whales in the spring, although 
bowhead whale hunting conditions there are often more difficult than 
elsewhere, and they do not hunt bowheads during seasons when Statoil's 
seismic operation would occur. Depending on the level of success during 
the spring bowhead hunt, Wainwright residents may be very dependent on 
the presence of belugas in a nearby lagoon system during July and 
August. Barrow residents focus hunting efforts on bowhead whales during 
the spring and generally do not hunt beluga then. However, Barrow 
residents also hunt in the fall, when Statoil expects to be conducting 
seismic surveys (though not near Barrow).
(1) Bowhead Whales
    Bowhead whale hunting is a key activity in the subsistence 
economies of northwest Arctic communities. The whale harvests have a 
great influence on social relations by strengthening the sense of 
Inupiat culture and heritage in addition to reinforcing family and 
community ties.
    An overall quota system for the hunting of bowhead whales was 
established by the International Whaling Commission (IWC) in 1977. The 
quota is now regulated through an agreement between NMFS and the Alaska 
Eskimo Whaling Commission (AEWC). The AEWC allots the number of bowhead 
whales that each whaling community may harvest annually (USDI/BLM 
2005). The annual take of bowhead whales has varied due to (a) changes 
in the allowable quota level and (b) year-to-year variability in ice 
and weather conditions, which strongly influence the success of the 
hunt.
    Bowhead whales migrate around northern Alaska twice each year, 
during the spring and autumn, and are hunted in both seasons. Bowhead 
whales are hunted from Barrow during the spring and the fall migration 
and animals are not successfully harvested every year. The spring hunt 
along Chukchi villages and at Barrow occurs after leads open due to the 
deterioration of pack ice; the spring hunt typically occurs from early 
April until the first week of June. The fall migration of bowhead 
whales that summer in the eastern Beaufort Sea typically begins in late 
August or September. Fall migration into Alaskan waters is primarily 
during September and October.
    In the fall, subsistence hunters use aluminum or fiberglass boats 
with outboards. Hunters prefer to take bowheads close to shore to avoid 
a long tow during which the meat can spoil, but Braund and Moorehead 
(1995) report that crews may (rarely) pursue whales as far as 50 mi (80 
km). The autumn bowhead hunt usually begins in Barrow in mid-September, 
and mainly occurs in the waters east and northeast of Point Barrow.
    The scheduling of this seismic survey has been discussed with 
representatives of those concerned with the subsistence bowhead hunt, 
most notably the AEWC, the Barrow Whaling Captains' Association, and 
the North Slope Borough (NSB) Department of Wildlife Management.
    The planned mobilization and start date for seismic surveys in the 
Chukchi Sea (~20 July and ~1 August) is well after the end of the 
spring bowhead migration and hunt at Wainwright and Barrow. Seismic 
operations will be conducted far offshore from Barrow and are not 
expected to conflict with subsistence hunting activities. Specific 
concerns of the Barrow whaling captains are addressed as part of the 
Plan of Cooperation with the AEWC (see below).
(2) Beluga Whales
    Beluga whales are available to subsistence hunters along the coast 
of Alaska in the spring when pack-ice conditions deteriorate and leads 
open up. Belugas may remain in coastal areas or lagoons through June 
and sometimes into July and August. The community of Point Lay is 
heavily dependent on the hunting of belugas in Kasegaluk Lagoon for 
subsistence meat. From 1983-1992 the average annual harvest was ~40 
whales (Fuller and George 1997). In Wainwright and Barrow, hunters 
usually wait until after the spring bowhead whale hunt is finished 
before turning their attention to hunting belugas. The average annual 
harvest of beluga whales taken by Barrow for 1962-1982 was five (MMS 
1996). The Alaska Beluga Whale Committee recorded that 23 beluga whales 
had been harvested by Barrow hunters from 1987 to 2002, ranging from 0 
in 1987, 1988 and 1995 to the high of 8 in 1997 (Fuller and George 
1997; Alaska Beluga Whale Committee 2002 in USDI/BLM 2005). The seismic 
survey activities take place well offshore, far away from areas that 
are used for beluga hunting by the Chukchi Sea communities. It is 
possible, but unlikely, that accessibility to belugas during the 
subsistence hunt could be impaired during the survey.
(3) Ringed Seals
    Ringed seals are hunted mainly from October through June. Hunting 
for these smaller mammals is concentrated during winter because bowhead 
whales, bearded seals and caribou are available through other seasons. 
In winter, leads and cracks in the ice off points of land and along the 
barrier islands are used for hunting ringed seals. The average annual 
ringed seal harvest was 49 seals in Point Lay, 86 in Wainwright, and 
394 in Barrow (Braund et al. 1993; USDI/BLM 2003, 2005). Although 
ringed seals are available year-round, the seismic survey will not 
occur during the primary period when these seals are typically 
harvested. Also, the seismic survey will be largely in offshore waters 
where the activities will not influence ringed seals in the nearshore 
areas where they are hunted.
(4) Spotted Seals
    The spotted seal subsistence hunt peaks in July and August along 
the shore where the seals haul out, but usually involves relatively few 
animals. Spotted seals typically migrate south by October to overwinter 
in the Bering Sea. During the fall migration spotted seals are hunted 
by the Wainright and Point Lay communities as the seals move south 
along the coast (USDI/BLM 2003). Spotted seals are also occasionally 
hunted in the area off Point Barrow and along the barrier islands of 
Elson Lagoon to the east (USDI/BLM 2005). The seismic survey will 
remain offshore of the coastal harvest area of these seals and should 
not conflict with harvest activities.
(5) Bearded Seals
    Bearded seals, although generally not favored for their meat, are 
important to subsistence activities in Barrow and Wainright, because of 
their skins. Six to nine bearded seal hides are used by whalers to 
cover each of the skin-covered boats traditionally used for spring 
whaling. Because of their valuable hides and large size, bearded seals 
are specifically sought. Bearded seals are harvested during the spring 
and summer months in the Chukchi Sea (USDI/BLM 2003, 2005). The animals 
inhabit the environment around the ice floes in the drifting nearshore 
ice pack, so hunting usually occurs from boats in the drift ice. Most 
bearded seals are harvested in coastal areas inshore of the

[[Page 49803]]

proposed survey so no conflicts with the harvest of bearded seals are 
expected.
    In the event that both marine mammals and hunters are near the 3D 
survey area when seismic surveys are in progress, the proposed project 
potentially could impact the availability of marine mammals for harvest 
in a small area immediately around the vessel, in the case of 
pinnipeds, and possibly in a large area in the case of migrating 
bowheads. However, the majority of marine mammals are taken by hunters 
within ~21 mi (~33 km) from shore (Figure 2 in Statoil's IHA 
application), and the seismic source vessel M/V Geo Celtic will remain 
far offshore, well outside the hunting areas. Considering the timing 
and location of the proposed seismic survey activities, as described 
earlier in the document, the proposed project is not expected to have 
any significant impacts to the availability of marine mammals for 
subsistence harvest. Specific concerns of the respective communities 
are addressed as part of the Plan of Cooperation between Statoil and 
the AEWC.

Potential Impacts to Subsistence Uses

    NMFS has defined ``unmitigable adverse impact'' in 50 CFR 216.103 
as:

    * * * an impact resulting from the specified activity: (1) That 
is likely to reduce the availability of the species to a level 
insufficient for a harvest to meet subsistence needs by: (i) Causing 
the marine mammals to abandon or avoid hunting areas; (ii) Directly 
displacing subsistence users; or (iii) Placing physical barriers 
between the marine mammals and the subsistence hunters; and (2) That 
cannot be sufficiently mitigated by other measures to increase the 
availability of marine mammals to allow subsistence needs to be met.

    Noise and general activity during Statoil's proposed open water 
marine seismic survey have the potential to impact marine mammals 
hunted by Native Alaskans. In the case of cetaceans, the most common 
reaction to anthropogenic sounds (as noted previously in this document) 
is avoidance of the ensonified area. In the case of bowhead whales, 
this often means that the animals divert from their normal migratory 
path by several kilometers. Additionally, general vessel presence in 
the vicinity of traditional hunting areas could negatively impact a 
hunt.
    In the case of subsistence hunts for bowhead whales in the Chukchi 
Sea, there could be an adverse impact on the hunt if the whales were 
deflected seaward (further from shore) in traditional hunting areas. 
The impact would be that whaling crews would have to travel greater 
distances to intercept westward migrating whales, thereby creating a 
safety hazard for whaling crews and/or limiting chances of successfully 
striking and landing bowheads.

Plan of Cooperation (POC or Plan)

    Regulations at 50 CFR 216.104(a)(12) require IHA applicants for 
activities that take place in Arctic waters to provide a POC or 
information that identifies what measures have been taken and/or will 
be taken to minimize adverse effects on the availability of marine 
mammals for subsistence purposes.
    Statoil states that it intends to maintain an open and transparent 
process with all stakeholders throughout the life-cycle of activities 
in the Chukchi Sea. Statoil began the stakeholder engagement process in 
2009 with meeting Chukchi Sea community leaders at the tribal, city, 
and corporate level. Statoil will continue to engage with leaders, 
community members, and subsistence groups, as well as local, state, and 
federal regulatory agencies throughout the exploration and development 
process.
    As part of stakeholder engagement, Statoil has conducted Plan of 
Cooperation (POC) meetings for its seismic operations in the Chukchi 
Sea in the communities and villages of Barrow, Wainwright, Point Lay, 
and Point Hope, and met with representatives of the Marine Mammal Co-
Management groups, including the AEWC, Ice Seal Commission, Alaska 
Beluga Whale Committee, Alaska Eskimo Walrus Commission, and the Nanuq 
Commission, on March 22, 2010. At each of these meetings, Statoil 
described the proposed survey program and measures it plans to take, or 
has taken, to minimize adverse effects its seismic survey may have on 
the availability of marine mammals for subsistence use. Statoil 
requested comments and feedback from subsistence users, and 
incorporated those comments and concerns in the final version of the 
POC, which was released on May 28, 2010. The final POC document 
contains the following information: (1) A description of the proposed 
marine seismic survey; (2) documentation of consultation with local 
communities and tribal governments; (3) a description of mitigation 
measures to reduce the impact of Statoil's planned activity on 
subsistence; (4) ongoing Chukchi Sea scientific research which Statoil 
is conducting to gather information on the marine environment; and (5) 
the future plans for meetings and communication with the affected 
subsistence Chukchi Sea communities.
    In addition, Statoil has entered into a Communication Protocol 
through a Participation Agreement with Shell to fund and staff a 
communications station out of Wainwright. The communications center 
will be staffed by Inupiat operators and on a 24/7 basis during the 
2010 subsistence bowhead whale hunt. Call center staff will receive 
notifications from vessels at least once every six hours and will plot 
the probable location of vessels on a map at the communications center. 
Communications center staff will apprise vessel operators of potential 
operations that may conflict with subsistence whaling activities.
    In addition, under the POC, at least five observers will be based 
aboard the seismic source vessel and at least three MMOs on the chase/
monitoring vessels when there are 24 hours of daylight, decreasing as 
the hours of daylight decrease. Primary roles for MMOs are defined as 
monitoring for the presence of marine mammals during all daylight 
airgun operations and during any nighttime ramp-up of the airguns. The 
MP provides additional detail on the number of MMOs, crew rotations, 
and observer qualification and training requirements, as well as 
monitoring methodology, including protocols for poor visibility and 
night monitoring, use of specialized field equipment, field data-
recording, verification, handling, and security, and field reporting. 
Lastly, the Participation Agreement provides that Statoil (and Shell) 
will fund a 24/7 communications center staffed by Inupiat personnel. 
The center will have contact with all vessels at least once every hour.
    Following the 2010 season, Statoil intends to have a post-season 
co-management meeting with the commissioners and committee heads to 
discuss results of mitigation measures and outcomes of the preceding 
season. The goal of the post-season meeting is to build upon the 
knowledge base, discuss successful or unsuccessful outcomes of 
mitigation measures, and possibly refine plans or mitigation measures 
if necessary.

Mitigation Measures

    In order to issue an incidental take authorization under Section 
101(a)(5)(D) of the MMPA, NMFS must set forth the permissible methods 
of taking pursuant to such activity, and other means of effecting the 
least practicable adverse impact on such species or stock and its 
habitat, paying particular attention to rookeries, mating grounds, and 
areas of similar significance, and on the

[[Page 49804]]

availability of such species or stock for taking for certain 
subsistence uses.
    For the Statoil open water marine seismic survey in the Chukchi 
Sea, Statoil worked with NMFS and proposed the following mitigation 
measures to minimize the potential impacts to marine mammals in the 
project vicinity as a result of the marine seismic survey activities.
    As part of the application, Statoil submitted to NMFS a Marine 
Mammal Monitoring and Mitigation Program (4MP) for its open water 
seismic survey in the Chukchi Sea during the 2010 open-water season. 
The objectives of the 4MP are:
     To ensure that disturbance to marine mammals and 
subsistence hunts is minimized and all permit stipulations are 
followed,
     To document the effects of the proposed survey activities 
on marine mammals, and
     To collect baseline data on the occurrence and 
distribution of marine mammals in the study area.
    For Statoil's 2010 open water marine seismic surveys in the Chukchi 
Sea, the following mitigation measures are required.
(1) Sound Source Measurements
    As described above, previous measurements of similar airgun arrays 
in the Chukchi Sea were used to model the distances at which received 
levels are likely to fall below 120, 160, 180, and 190 dB re 1 [mu]Pa 
(rms) from the planned airgun sources. These modeled distances will be 
used as temporary safety radii until measurements of the airgun sound 
source are conducted. The measurements will be made at the beginning of 
the field season and the measured radii used for the remainder of the 
survey period.
    The objectives of the sound source verification measurements 
planned for 2010 in the Chukchi Sea will be to measure the distances in 
the broadside and endfire directions at which broadband received levels 
reach 190, 180, 170, 160, and 120 dB re 1 [mu]Pa (rms) for the energy 
source array combinations that may be used during the survey 
activities. The configurations will include at least the full array and 
the operation of a single mitigation source that will be used during 
power downs. The measurements of energy source array sounds will be 
made by an acoustics contractor at the beginning of the survey and the 
distances to the various radii will be reported as soon as possible 
after recovery of the equipment. The primary radii of concern will be 
the 190 and 180 dB safety radii for pinnipeds and cetaceans, 
respectively, and the 160 dB radii for zone of influence (ZOI). In 
addition to reporting the radii of specific regulatory concern, nominal 
distances to other sound isopleths down to 120 dB (rms) will be 
reported in increments of 10 dB.
    Data will be previewed in the field immediately after download from 
the ocean bottom hydrophone (OBH) instruments. An initial sound source 
analysis will be supplied to NMFS and the airgun operators within 120 
hours of completion of the measurements, if possible. The report will 
indicate the distances to sound levels between 190 dB re 1 [mu]Pa (rms) 
and 120 dB re 1 [mu]Pa (rms) based on fits of empirical transmission 
loss formulae to data in the endfire and broadside directions. The 120-
hour report findings will be based on analysis of measurements from at 
least three of the OBH systems. A more detailed report including 
analysis of data from all OBH systems will be issued to NMFS as part of 
the 90-day report following completion of the acoustic program.
(2) Safety and Disturbance Zones
    Under current NMFS guidelines, ``safety radii'' for marine mammal 
exposure to impulse sources are customarily defined as the distances 
within which received sound levels are >=180 dB re 1 [mu]Pa (rms) for 
cetaceans and >=190 dB re 1 [mu]Pa (rms) for pinnipeds. These safety 
criteria are based on an assumption that SPL received at levels lower 
than these will not injure these animals or impair their hearing 
abilities, but that SPL received at higher levels might have some such 
effects. Disturbance or behavioral effects to marine mammals from 
underwater sound may occur after exposure to sound at distances greater 
than the safety radii (Richardson et al. 1995).
    Initial safety and disturbance radii for the sound levels produced 
by the survey activities have been estimated from measurements of 
similar seismic arrays used in the Chukchi Sea in previous years. These 
radii will be used for mitigation purposes until results of direct 
measurements are available early during the exploration activities.
    The basis for the estimation of distances to the four received 
sound levels from the proposed 3000 in \3\ airgun array operating at a 
depth of 20 ft (6 m) are the 2006, 2007 and 2008 sound source 
verification (SSV) measurements in the Chukchi Sea of a similar array, 
towed at a similar depth. The measured airgun array had a total 
discharge volume of 3,147 in \3\ and was composed of three identically-
tuned Bolt airgun sub-arrays, totaling 24 airguns (6 clusters of 2 
airguns and 12 single airguns). The proposed 3,000 in \3\ array is also 
composed of three strings with a total of 26 active airguns in 13 
clusters. The difference in discharge volume would lead to an expected 
loss of less than 0.2 dB and is neglected in this assessment. The 
estimated source level for the full 3,000 in \3\ array is 245 dB re 1 
[mu]PA (rms). Without measurement data for the specific site to be 
surveyed, it is reasonable to adopt the maximum distances obtained from 
a similar array during previous measurements in the Chukchi Sea. Table 
1 summarizes the distances to received levels of 190, 180 160, and 120 
dB re 1 [mu]Pa (rms) that are adopted for the analysis for the proposed 
survey. Distances for received levels of 120 dB are highly variable, in 
part because the bottom geoacoustic properties will have a major effect 
on received levels at such distances.
    To estimate the distances to various received levels from the 60 in 
\3\ mitigation gun the data from previous measurements of a 30 in \3\ 
gun were used. In general the pressure increase relative to a 30 in \3\ 
gun can be derived by calculating the square root of (60/30), which is 
1.41. This means that the dB levels for the sound pressure levels of a 
60 in \3\ will increase by approximately 3 dB (20Log[1.41]) compared to 
the 30 in \3\ gun. The distances as summarized in Table 1 were derived 
by adding 3 dB to the constant term of the equation RL = 226.6-
21.2log(R)-0.00022R. The estimated source level of this single 60 in 
\3\ airgun is 230 dB re 1 [mu]Pa (rms).

[[Page 49805]]



 Table 1--Estimated Distances to Received Sound Levels >=190, 180, 170,
160, and 120 dB re 1 [mu]Pa (rms) From the 3,000 in \3\ Airgun Array and
   the 60 in \3\ Mitigation Gun of the Proposed Seismic Survey. These
  Distances are Based on Measurements in the Chukchi Sea From a Similar
                              Airgun Array.
------------------------------------------------------------------------
                                               Distance (m)
 Received Levels (dB re 1 [mu]Pa ---------------------------------------
              rms)                   3,000 in \3\          60 in \3\
------------------------------------------------------------------------
                                  (full airgun        (mitigation
                                   array).             airgun)
190.............................  700...............  70
180.............................  2,500.............  220
160.............................  13,000............  1,800
120.............................  70,000-120,000....  50,000
------------------------------------------------------------------------

    An acoustics contractor will perform the direct measurements of the 
received levels of underwater sound versus distance and direction from 
the energy source arrays using calibrated hydrophones. The acoustic 
data will be analyzed as quickly as reasonably practicable in the field 
and used to verify (and if necessary adjust) the safety distances. The 
field report will be made available to NMFS and the MMOs within 120 hrs 
of completing the measurements. The mitigation measures to be 
implemented at the 190 and 180 dB sound levels will include power downs 
and shut downs as described below.
(3) Power Downs and Shut Downs
    A power-down is the immediate reduction in the number of operating 
energy sources from all firing to some smaller number. A shutdown is 
the immediate cessation of firing of all energy sources. The arrays 
will be immediately powered down whenever a marine mammal is sighted 
approaching close to or within the applicable safety zone of the full 
arrays but is outside or about to enter the applicable safety zone of 
the single mitigation source. If a marine mammal is sighted within the 
applicable safety zone of the single mitigation airgun, the entire 
array will be shut down (i.e., no sources firing).
    Following a power-down or shutdown, operation of the airgun array 
will not resume until the marine mammal has cleared the applicable 
safety zone. The animal will be considered to have cleared the safety 
zone if it:
     Is visually observed to have left the safety zone;
     Has not been seen within the zone for 15 min in the case 
of small odontocetes and pinnipeds; or
     Has not been seen within the zone for 30 min in the case 
of mysticetes.
    In the unanticipated event that an injured or dead marine mammal is 
sighted within an area where the holder of this Authorization deployed 
and utilized seismic airguns within the past 24 hours, immediately 
shutdown the seismic airgun array and notify the Marine Mammal 
Stranding Network within 24 hours of the sighting (telephone: 1-800-
853-1964).
    In the event that the marine mammal has been determined to have 
been deceased for at least 72 hours, as certified by the lead MMO 
onboard the source vessel, and no other marine mammals have been 
reported injured or dead during that same 72 hour period, the airgun 
array may be restarted by conducting the necessary ramp-up procedures 
described below upon completion of a written certification by the MMO. 
The certification must include the following: Species or description of 
the animal(s); the condition of the animal(s) (including carcass 
condition if the animal is dead); location and time of first discovery; 
observed behaviors (if alive); and photographs or video (if available). 
Within 24 hours after the event, Statoil must notify the designated 
staff person by telephone or email of the event and ensure that the 
written certification is provided to the NMFS staff person.
    In the event that the marine mammal injury resulted from something 
other than seismic airgun operations (e.g., gunshot wound, polar bear 
attack), as certified by the lead MMO onboard the seismic vessel, the 
airgun array may be restarted by conducting the necessary ramp-up 
procedures described below upon completion of a written certification 
by the MMO. The certification must include the following: Species or 
description of the animal(s); the condition of the animal(s) (including 
carcass condition if the animal is dead); location and time of first 
discovery; observed behaviors (if alive); and photographs or video (if 
available). Within 24 hours after the event, Statoil must notify the 
designated staff person by telephone or email of the event and ensure 
that the written certification is provided to the NMFS staff person.
(4) Ramp Ups
    A ramp up of an airgun array provides a gradual increase in sound 
levels, and involves a stepwise increase in the number and total volume 
of airguns firing until the full volume is achieved.
    The purpose of a ramp up (or ``soft start'') is to ``warn'' 
cetaceans and pinnipeds in the vicinity of the airguns and to provide 
time for them to leave the area and thus avoid any potential injury or 
impairment of their hearing abilities.
    During the proposed seismic survey, the seismic operator will ramp 
up the airgun arrays slowly. Full ramp ups (i.e., from a cold start 
after a shut down, when no airguns have been firing) will begin by 
firing a single airgun in the array. The minimum duration of a shut-
down period, i.e., without air guns firing, which must be followed by a 
ramp up, is typically the amount of time it would take the source 
vessel to cover the 180-dB safety radius. The actual time period 
depends on ship speed and the size of the 180-dB safety radius. That 
period is estimated to be about 15-20 minutes based on the modeling 
results described above and a survey speed of 4 knots.
    A full ramp up, after a shut down, will not begin until there has 
been a minimum of 30 min of observation of the safety zone by MMOs to 
assure that no marine mammals are present. The entire safety zone must 
be visible during the 30-minute lead-in to a full ramp up. If the 
entire safety zone is not visible, then ramp up from a cold start 
cannot begin. If a marine mammal(s) is sighted within the safety zone 
during the 30-minute watch prior to ramp up, ramp up will be delayed 
until the marine mammal(s) is sighted outside of the safety zone or the 
animal(s) is not sighted for at least 15-30 minutes: 15 minutes for 
small odontocetes and pinnipeds, or 30 minutes for baleen whales and 
large odontocetes.
    During turns and transit between seismic transects, at least one 
airgun will remain operational. The ramp-up procedure still will be 
followed when

[[Page 49806]]

increasing the source levels from one airgun to the full arrays. 
However, keeping one airgun firing will avoid the prohibition of a cold 
start during darkness or other periods of poor visibility. Through use 
of this approach, seismic operations can resume upon entry to a new 
transect without a full ramp up and the associated 30-minute lead-in 
observations. MMOs will be on duty whenever the airguns are firing 
during daylight, and during the 30-min periods prior to ramp-ups as 
well as during ramp-ups. Daylight will occur for 24 h/day until mid-
August, so until that date MMOs will automatically be observing during 
the 30-minute period preceding a ramp up. Later in the season, MMOs 
will be called out at night to observe prior to and during any ramp up. 
The seismic operator and MMOs will maintain records of the times when 
ramp-ups start, and when the airgun arrays reach full power.
(5) Mitigation Measures Concerning Baleen Whale Aggregations
    A 160-dB vessel monitoring zone for large whales will be 
established and monitored in the Chukchi Sea during all seismic 
surveys. Whenever an aggregation of bowhead whales or gray whales (12 
or more whales of any age/sex class that appear to be engaged in a 
nonmigratory, significant biological behavior (e.g., feeding, 
socializing)) are observed during an aerial or vessel monitoring 
program within the 160-dB safety zone around the seismic activity, the 
seismic operation will not commence or will shut down, until two 
consecutive surveys (aerial or vessel) indicate they are no longer 
present within the 160-dB safety zone of seismic-surveying operations.
    Survey information, especially information about bowhead whale cow/
calf pairs or feeding bowhead or gray whales, shall be provided to NMFS 
as required in MMPA authorizations, and will form the basis for NMFS 
determining whether additional mitigation measures, if any, will be 
required over a given time period.
(6) Mitigation Measures Concerning Vessel Speed and Directions
    Furthermore, the following measures concerning vessel speed and 
directions are required for Statoil's 2010 open water marine seismic 
surveys in the Chukchi Sea:
    (1) All vessels should reduce speed when within 300 yards (274 m) 
of whales, and those vessels capable of steering around such groups 
should do so. Vessels may not be operated in such a way as to separate 
members of a group of whales from other members of the group;
    (2) Avoid multiple changes in direction and speed when within 300 
yards (274 m) of whales; and
    (3) When weather conditions require, such as when visibility drops, 
support vessels must adjust speed accordingly to avoid the likelihood 
of injury to whales.
(7) Subsistence Mitigation Measures
    The following measures, plans, and programs will be implemented by 
Statoil during its 2010 open water marine seismic survey in the Chukchi 
Sea to monitor and mitigate potential impacts to subsistence users and 
resources. These measures, plans, and programs have been effective in 
past seasons of work in the Arctic and were developed in past 
consultations with potentially affected communities.
    Statoil will not be entering the Chukchi Sea until early August, so 
there will be no potential conflict with spring bowhead whale or beluga 
subsistence whaling in the polynya zone. Statoil's seismic survey area 
is ~100 mi (~161 km) northwest of Wainwright which reduces the 
potential impact to subsistence hunting activities occurring along the 
Chukchi Sea coast. The communication center in Wainwright will be 
jointly funded by Statoil and other operators, and Statoil will 
routinely call the communication center according to the established 
protocol while in the Chukchi Sea. Statoil plans to have one major crew 
change which will take place in Nome, AK, and will not involve the use 
of helicopters. Statoil does have a contingency plan for a potential 
transfer of a small number of crew via ship-to-shore vessel at 
Wainwright. If this should become necessary, the Wainwright 
communications center will be contacted to determine the appropriate 
vessel route and timing to avoid potential conflict with subsistence 
users.
    Following completion of the 2010 Chukchi Sea open water marine 
seismic surveys, Statoil will conduct a co-management meeting with the 
commissioners and committee heads to discuss results of mitigation 
measures and outcomes of the preceding season. The goal of the post-
season meeting is to build upon the knowledge base, discuss successful 
or unsuccessful outcomes of mitigation measures, and possibly refine 
plans or mitigation measures if necessary.

Mitigation Conclusions

    NMFS has carefully evaluated the applicant's proposed mitigation 
measures and considered a range of other measures in the context of 
ensuring that NMFS prescribes the means of effecting the least 
practicable impact on the affected marine mammal species and stocks and 
their habitat. Our evaluation of potential measures included 
consideration of the following factors in relation to one another:
     The manner in which, and the degree to which, the 
successful implementation of the measure is expected to minimize 
adverse impacts to marine mammals;
     The proven or likely efficacy of the specific measure to 
minimize adverse impacts as planned; and
     The practicability of the measure for applicant 
implementation.
    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has determined that the 
proposed mitigation measures provide the means of effecting the least 
practicable impact on marine mammal species or stocks and their 
habitat, paying particular attention to rookeries, mating grounds, and 
areas of similar significance.

Monitoring and Reporting Measures

    In order to issue an ITA for an activity, Section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth ``requirements pertaining to 
the monitoring and reporting of such taking''. The MMPA implementing 
regulations at 50 CFR 216.104 (a)(13) indicate that requests for ITAs 
must include the suggested means of accomplishing the necessary 
monitoring and reporting that will result in increased knowledge of the 
species and of the level of taking or impacts on populations of marine 
mammals that are expected to be present in the proposed action area.

Monitoring Measures

    The following monitoring measures are required for Statoil's 2010 
open water marine seismic surveys in the Chukchi Sea.
(1) Vessel-Based MMOs
    Vessel-based monitoring for marine mammals will be done by trained 
MMOs throughout the period of marine survey activities. MMOs will 
monitor the occurrence and behavior of marine mammals near the survey 
vessel during all daylight periods during operation and during most 
daylight periods when airgun operations are not occurring. MMO duties 
will include watching for and identifying marine mammals, recording 
their numbers, distances, and reactions to the survey operations, and 
documenting ``take by harassment'' as defined by NMFS.

[[Page 49807]]

    A sufficient number of MMOs will be required onboard the survey 
vessel to meet the following criteria: (1) 100% monitoring coverage 
during all periods of survey operations in daylight; (2) maximum of 4 
consecutive hours on watch per MMO; and (3) maximum of 12 hours of 
watch time per day per MMO.
    During seismic operations when there is 24 hrs of daylight, five 
MMOs will be based aboard the seismic source vessel and at least three 
MMOs on the chase/monitoring vessels.
    MMO teams will consist of Inupiat observers and experienced field 
biologists. An experienced field crew leader will supervise the MMO 
team onboard the survey vessel. New observers shall be paired with 
experienced observers to avoid situations where lack of experience 
impairs the quality of observations. The total number of MMOs may 
decrease later in the season as the duration of daylight decreases.
    Statoil anticipates one crew change to occur approximately half-way 
through the season. During crew rotations detailed hand-over notes will 
be provided to the incoming crew leader by the outgoing leader. Other 
communications such as email, fax, and/or phone communication between 
the current and oncoming crew leaders during each rotation will also 
occur when possible. In the event of an unexpected crew change Statoil 
will facilitate such communications to insure monitoring consistency 
among shifts.
    Crew leaders and most other biologists serving as observers in 2010 
will be individuals with experience as observers during one or more of 
the 1996-2009 seismic or shallow hazards monitoring projects in Alaska, 
the Canadian Beaufort, or other offshore areas in recent years.
    Biologist-observers will have previous marine mammal observation 
experience, and field crew leaders will be highly experienced with 
previous vessel-based marine mammal monitoring and mitigation projects. 
Resumes for those individuals will be provided to NMFS for review and 
acceptance of their qualifications. Inupiat observers will be 
experienced in the region, familiar with the marine mammals of the 
area, and complete a NMFS-approved observer training course designed to 
familiarize individuals with monitoring and data collection procedures. 
A marine mammal observers' handbook, adapted for the specifics of the 
planned survey program, will be prepared and distributed beforehand to 
all MMOs.
    Most observers, including Inupiat observers, will also complete a 
two-day training and refresher session on marine mammal monitoring, to 
be conducted shortly before the anticipated start of the 2010 open-
water season. Any exceptions will have or receive equivalent experience 
or training. The training session(s) will be conducted by qualified 
marine mammalogists with extensive crew-leader experience during 
previous vessel-based seismic monitoring programs. Observers should be 
trained using visual aids (e.g., videos, photos), to help them identify 
the species that they are likely to encounter in the conditions under 
which the animals will likely be seen.
    If there are Alaska Native MMOs, the MMO training that is conducted 
prior to the start of the survey activities should be conducted with 
both Alaska Native MMOs and biologist MMOs being trained at the same 
time in the same room. There should not be separate training courses 
for the different MMOs.
    Primary objectives of the training include:
     Review of the marine mammal monitoring plan for this 
project, including any amendments specified by NMFS in the IHA, by 
USFWS and by MMS, or by other agreements in which Statoil may elect to 
participate;
     Review of marine mammal sighting, identification, and 
distance estimation methods;
     Review of operation of specialized equipment (reticle 
binoculars, night vision devices, and GPS system);
     Review of, and classroom practice with, data recording and 
data entry systems, including procedures for recording data on marine 
mammal sightings, monitoring operations, environmental conditions, and 
entry error control. These procedures will be implemented through use 
of a customized computer database and laptop computers; and
     Review of the specific tasks of the Inupiat Communicator.
    Observers should understand the importance of classifying marine 
mammals as ``unknown'' or ``unidentified'' if they cannot identify the 
animals to species with confidence. In those cases, they should note 
any information that might aid in the identification of the marine 
mammal sighted. For example, for an unidentified mysticete whale, the 
observers should record whether the animal had a dorsal fin.
    MMOs will watch for marine mammals from the best available vantage 
point on the survey vessel, typically the bridge. MMOs will scan 
systematically with the unaided eye and 7 x 50 reticle binoculars, 
supplemented with 20 x 60 image-stabilized Zeiss Binoculars or Fujinon 
25 x 150 ``Big-eye'' binoculars and night-vision equipment when needed. 
With two or three observers on watch, the use of big eyes should be 
paired with searching by naked eye, the latter allowing visual coverage 
of nearby areas to detect marine mammals. Personnel on the bridge will 
assist the MMOs in watching for marine mammals.
    Observers should attempt to maximize the time spent looking at the 
water and guarding the safety radii. They should avoid the tendency to 
spend too much time evaluating animal behavior or entering data on 
forms, both of which detract from their primary purpose of monitoring 
the safety zone.
    Observers should use the best possible positions for observing 
(e.g., outside and as high on the vessel as possible), taking into 
account weather and other working conditions. MMOs shall carefully 
document visibility during observation periods so that total estimates 
of take can be corrected accordingly.
    Information to be recorded by marine mammal observers will include 
the same types of information that were recorded during recent 
monitoring programs associated with Industry activity in the Arctic 
(e.g., Ireland et al., 2009). When a mammal sighting is made, the 
following information about the sighting will be recorded:
    (A) Species, group size, age/size/sex categories (if determinable), 
behavior when first sighted and after initial sighting, heading (if 
consistent), bearing and distance from the MMO, apparent reaction to 
activities (e.g., none, avoidance, approach, paralleling, etc.), 
closest point of approach, and behavioral pace;
    (B) Time, location, speed, activity of the vessel, sea state, ice 
cover, visibility, and sun glare;
    (C) The positions of other vessel(s) in the vicinity of the MMO 
location; and
    (D) Whether adjustments were made to Statoil's activity status.
    The ship's position, speed of support vessels, and water 
temperature, water depth, sea state, ice cover, visibility, and sun 
glare will also be recorded at the start and end of each observation 
watch, every 30 minutes during a watch, and whenever there is a change 
in any of those variables.
    Distances to nearby marine mammals will be estimated with 
binoculars (Fujinon 7 x 50 binoculars) containing a reticle to measure 
the vertical angle of the line of sight to the animal relative to the 
horizon. MMOs may use a laser rangefinder to test and improve their

[[Page 49808]]

abilities for visually estimating distances to objects in the water. 
However, previous experience showed that a Class 1 eye-safe device was 
not able to measure distances to seals more than about 230 ft (70 m) 
away. The device was very useful in improving the distance estimation 
abilities of the observers at distances up to about 1,968 ft (600 m)--
the maximum range at which the device could measure distances to highly 
reflective objects such as other vessels. Humans observing objects of 
more-or-less known size via a standard observation protocol, in this 
case from a standard height above water, quickly become able to 
estimate distances within about  20% when given immediate 
feedback about actual distances during training.
    Statoil plans to conduct the marine seismic survey 24 hr/day. 
Regarding nighttime operations, note that there will be no periods of 
total darkness until mid-August. When operating under conditions of 
reduced visibility attributable to darkness or to adverse weather 
conditions, night-vision equipment (``Generation 3'' binocular image 
intensifiers, or equivalent units) will be available for use.
(2) Acoustic Monitoring

Sound Source Measurements

    As described above, previous measurements of airguns in the Chukchi 
Sea were used to estimate the distances at which received levels are 
likely to fall below 120, 160, 180, and 190 dB re 1 [mu]Pa (rms) from 
the planned airgun sources. These modeled distances will be used as 
temporary safety radii until measurements of the airgun sound source 
are conducted. The measurements will be made at the beginning of the 
field season and the measured radii used for the remainder of the 
survey period. An acoustics contractor with experience in the Arctic 
conducting similar measurements in recent years will use their 
equipment to record and analyze the underwater sounds and write the 
summary reports as described below.
    The objectives of the sound source verification measurements 
planned for 2010 in the Chukchi Sea will be (1) to measure the 
distances in the broadside and endfire directions at which broadband 
received levels reach 190, 180, 170, 160, and 120 dB re 1 [mu]Pa (rms) 
for the energy source array combinations that may be used during the 
survey activities. The configurations will include at least the full 
array and the operation of a single mitigation source that will be used 
during power downs. The measurements of energy source array sounds will 
be made by an acoustics contractor at the beginning of the survey and 
the distances to the various radii will be reported as soon as possible 
after recovery of the equipment. The primary radii of concern will be 
the 190 and 180 dB safety radii for pinnipeds and cetaceans, 
respectively, and the 160 dB disturbance radii. In addition to 
reporting the radii of specific regulatory concern, nominal distances 
to other sound isopleths down to 120 dB re 1 [mu]Pa (rms) will be 
reported in increments of 10 dB.
    Data will be previewed in the field immediately after download from 
the hydrophone instruments. An initial sound source analysis will be 
supplied to NMFS and the airgun operators within 120 hours of 
completion of the measurements, if possible. The report will indicate 
the distances to sound levels based on fits of empirical transmission 
loss formulae to data in the endfire and broadside directions. A more 
detailed report will be issued to NMFS as part of the 90-day report 
following completion of the acoustic program.

2010 Shared Science Program

    Statoil, Shell, and ConocoPhillips (CPAI) are jointly funding an 
extensive science program in the Chukchi Sea. This program will be 
carried out by Olgoonik-Fairweather LLC (OFJV) with the vessels 
Norseman II and Westward Wind during the 2010 open water season. The 
science program is not part of the Statoil seismic program, but worth 
mentioning in this context due to the acoustic monitoring array 
deployed within the seismic survey area as shown in Figures 1 and 2 of 
Statoil's IHA application. The science program components include:
     Acoustics Monitoring
     Fisheries Ecology
     Benthic Ecology
     Plankton Ecology
     Mammals
     Seabirds
     Physical Oceanography
    The 2010 program continues the acoustic monitoring programs of 
2006-2009 with a total of 44 acoustic recorders distributed both 
broadly across the Chukchi lease area and nearshore environment and 
intensively on the Statoil, Burger (Shell), and Klondike (CPAI) lease 
holdings. The recorders will be deployed in late July or early August 
and will be retrieved in early to mid-October, depending on ice 
conditions. The recorders will be the Advanced Multi-Channel Acoustic 
Recorder (AMAR) and the Autonomous Underwater Recorder for Acoustic 
Listening (AURAL) model acoustic buoys set to record at 16 kHz sample 
rate. These are the same recorder models and same sample rates that 
have been used for this program from 2006-2009. The broad area arrays 
are designed to capture both general background soundscape data, 
seismic survey sounds and marine mammal call data across the lease 
area. From these recordings we have been able to gain insight into 
large-scale distributions of marine mammals, identification of marine 
mammal species present, movement and migration patterns, and general 
abundance data. The site specific focused arrays are designed to also 
support localization of marine mammal calls on and around the 
leaseholdings. In the case of the Statoil prospect, where Statoil 
intends to conduct seismic data acquisition in 2010, localized calls 
will enable investigators to understand responses of marine mammals to 
survey operations both in terms of distribution around the operation 
and behavior (i.e., calling behavior). The site specific array will 
consist of 7 AMAR recorders deployed in a hexagonal configuration as 
shown in Figure 2 of Statoil's 4MP, with inter-recorder spacing of 8 km 
(12.9 mi). These recorders are the same types that were used 
successfully in the 2009 site-specific acoustic monitoring program on 
Shell and CPAI prospects. The recorded sample resolution is 24-bits and 
sample frequency is 16 kHz, which is sufficient to capture part or all 
of the sounds produced by the marine mammal species known to be 
present, with the exception of harbor porpoise. The recorders will be 
synchronized to support localization of calling bowhead whales. Other 
species' calls are typically detected from distances less than the 8 km 
recorder separation. Consequently the multi-sensor triangulation 
method, that is used for bowheads calls, will not be used to determine 
calling locations of other species; however, detection of other 
species' calls indicates the animal's position within a circular region 
of radius equal to the maximum detection distances of a few kilometers.

Reporting Measures

(1) SSV Report
    A report on the preliminary results of the acoustic verification 
measurements, including as a minimum the measured 190-, 180-, 160-, and 
120-dB re 1 [mu]Pa (rms) radii of the source vessel(s) and the support 
vessels, will be submitted within 120 hr after collection and analysis 
of those measurements at the start of the field season. This report 
will specify the distances of the safety zones

[[Page 49809]]

that were adopted for the marine survey activities.
(2) Technical Reports
    The results of Statoil's 2010 open water marine seismic survey 
monitoring program (i.e., vessel-based and acoustic), including 
estimates of ``take'' by harassment, will be presented in the ``90-
day'' and Final Technical reports. The Technical Reports will include: 
(a) Summaries of monitoring effort (e.g., total hours, total distances, 
and marine mammal distribution through the study period, accounting for 
sea state and other factors affecting visibility and detectability of 
marine mammals); (b) analyses of the effects of various factors 
influencing detectability of marine mammals (e.g., sea state, number of 
observers, and fog/glare); (c) species composition, occurrence, and 
distribution of marine mammal sightings, including date, water depth, 
numbers, age/size/gender categories (if determinable), group sizes, and 
ice cover; (d) analyses of the effects of survey operations; (e) 
sighting rates of marine mammals during periods with and without airgun 
activities (and other variables that could affect detectability); (f) 
initial sighting distances versus airgun activity state; (g) closest 
point of approach versus airgun activity state; (h) observed behaviors 
and types of movements versus airgun activity state; (i) numbers of 
sightings/individuals seen versus airgun activity state; (j) 
distribution around the survey vessel versus airgun activity state; and 
(k) estimates of take by harassment. In addition, Statoil shall provide 
all spatial data on charts (always including vessel location) and make 
all data available in the report, preferably electronically, for 
integration with data from other companies. Statoil shall also 
accommodate specific requests for raw data, including tracks of all 
vessels and aircraft (if available) associated with the operation and 
activity logs documenting when and what types of sounds are introduced 
into the environment by the operation.
    The initial technical report is due to NMFS within 90 days of the 
completion of Statoil's Chukchi Sea open water marine seismic surveys. 
The ``90-day'' report will be subject to review and comment by NMFS. 
Any recommendations made by NMFS must be addressed in the final report 
prior to acceptance by NMFS.
(3) Comprehensive Report
    Following the 2010 open-water season a comprehensive report 
describing the vessel-based monitoring and acoustic monitoring programs 
will be prepared. The comprehensive report will describe the methods, 
results, conclusions and limitations of each of the individual data 
sets in detail. The report will also integrate (to the extent possible) 
the studies into a broad-based assessment of industry activities, and 
other activities that occur in the Chukchi Sea, and their impacts on 
marine mammals during 2010. The report will help to establish long-term 
data sets that can assist with the evaluation of changes in the Chukchi 
Sea ecosystem. The report will attempt to provide a regional synthesis 
of available data on industry activity in offshore areas of northern 
Alaska that may influence marine mammal density, distribution and 
behavior.
(4) Notification of Injured or Dead Marine Mammals
    Statoil will notify NMFS' Office of Protected Resources and NMFS' 
Stranding Network within 48 hours of sighting an injured or dead marine 
mammal in the vicinity of marine survey operations. Statoil will 
provide NMFS with the species or description of the animal(s), the 
condition of the animal(s) (including carcass condition if the animal 
is dead), location, time of first discovery, observed behaviors (if 
alive), and photo or video (if available).
    In the event that an injured or dead marine mammal is found by 
Statoil that is not in the vicinity of the proposed open water marine 
survey program, Statoil will report the same information as listed 
above as soon as operationally feasible to NMFS.
Negligible Impact and Small Numbers Analysis and Determination
    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.'' In making a negligible impact determination, 
NMFS considers a variety of factors, including but not limited to: (1) 
The number of anticipated mortalities; (2) the number and nature of 
anticipated injuries; (3) the number, nature, intensity, and duration 
of Level B harassment; and (4) the context in which the takes occur.
    No injuries or mortalities are anticipated to occur as a result of 
Statoil's proposed 2010 open water marine seismic surveys in the 
Chukchi Seas, and none are proposed to be authorized. Additionally, 
animals in the area are not expected to incur hearing impairment (i.e., 
TTS or PTS) or non-auditory physiological effects. Takes will be 
limited to Level B behavioral harassment. Although it is possible that 
some individuals of marine mammals may be exposed to sounds from marine 
survey activities more than once, the expanse of these multi-exposures 
are expected to be less extensive since both the animals and the survey 
vessels will be moving constantly in and out of the survey areas.
    Most of the bowhead whales encountered during the summer will 
likely show overt disturbance (avoidance) only if they receive airgun 
sounds with levels >= 160 dB re 1 [mu]Pa (rms). Odontocete reactions to 
seismic energy pulses are usually assumed to be limited to shorter 
distances from the airgun(s) than are those of mysticetes, probably in 
part because odontocete low-frequency hearing is assumed to be less 
sensitive than that of mysticetes. However, at least when in the 
Canadian Beaufort Sea in summer, belugas appear to be fairly responsive 
to seismic energy, with few being sighted within 6-12 mi (10-20 km) of 
seismic vessels during aerial surveys (Miller et al., 2005). Belugas 
will likely occur in small numbers in the Chukchi Sea during the survey 
period and few will likely be affected by the survey activity. In 
addition, due to the constant moving of the seismic survey vessel, the 
duration of the noise exposure by cetaceans to seismic impulse would be 
brief. For the same reason, it is unlikely that any individual animal 
would be exposed to high received levels multiple times.
    Taking into account the mitigation measures that are planned, 
effects on cetaceans are generally expected to be restricted to 
avoidance of a limited area around the survey operation and short-term 
changes in behavior, falling within the MMPA definition of ``Level B 
harassment''. Furthermore, the estimated numbers of animals potentially 
exposed to sound levels sufficient to cause appreciable disturbance are 
very low percentages of the population sizes in the Bering-Chukchi-
Beaufort seas, as described above.
    The many reported cases of apparent tolerance by cetaceans of 
seismic exploration, vessel traffic, and some other human activities 
show that co-existence is possible. Mitigation measures such as 
controlled vessel speed, dedicated marine mammal observers, non-
pursuit, and shut downs or power downs when marine mammals are seen 
within defined ranges will further reduce short-term reactions and 
minimize any effects on hearing sensitivity. In all cases, the effects 
are expected to be short-term, with no lasting biological consequence.
    Some individual pinnipeds may be exposed to sound from the proposed

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marine surveys more than once during the time frame of the project. 
However, as discussed previously, due to the constant moving of the 
survey vessel, the probability of an individual pinniped being exposed 
multiple times is much lower than if the source is stationary. 
Therefore, NMFS has preliminarily determined that the exposure of 
pinnipeds to sounds produced by the proposed marine seismic survey in 
the Chukchi Sea is not expected to result in more than Level B 
harassment and is anticipated to have no more than a negligible impact 
on the animals.
    Of the twelve marine mammal species likely to occur in the proposed 
marine survey area, only the bowhead, fin, and humpback whales are 
listed as endangered under the ESA. These species are also designated 
as ``depleted'' under the MMPA. Despite these designations, the Bering-
Chukchi-Beaufort stock of bowheads has been increasing at a rate of 3.4 
percent annually for nearly a decade (Allen and Angliss, 2010). 
Additionally, during the 2001 census, 121 calves were counted, which 
was the highest yet recorded. The calf count provides corroborating 
evidence for a healthy and increasing population (Allen and Angliss, 
2010). The occurrence of fin and humpback whales in the proposed marine 
survey areas is considered very rare. There is no critical habitat 
designated in the U.S. Arctic for the bowhead, fin, and humpback whale. 
The bearded and ringed seals are ``candidate species'' under the ESA, 
meaning they are currently being considered for listing but are not 
designated as depleted under the MMPA. None of the other three species 
that may occur in the project area are listed as threatened or 
endangered under the ESA or designated as depleted under the MMPA.
    Potential impacts to marine mammal habitat were discussed 
previously in this document (see the ``Anticipated Effects on Habitat'' 
section). Although some disturbance is possible to food sources of 
marine mammals, the impacts are anticipated to be minor enough as to 
not affect rates of recruitment or survival of marine mammals in the 
area. Based on the vast size of the Arctic Ocean where feeding by 
marine mammals occurs versus the localized area of the marine survey 
activities, any missed feeding opportunities in the direct project area 
would be minor based on the fact that other feeding areas exist 
elsewhere.
    The estimated takes proposed to be authorized represent 4.95% of 
the Eastern Chukchi Sea population of approximately 3,700 beluga whales 
(Angliss and Allen, 2009), 0.62% of Aleutian Island and Bering Sea 
stock of approximately 340 killer whales, 0.04% of Bering Sea stock of 
approximately 48,215 harbor porpoises, 0.81% of the Eastern North 
Pacific stock of approximately 17,752 gray whales, 1.11% of the Bering-
Chukchi-Beaufort population of 14,247 individuals assuming 3.4 percent 
annual population growth from the 2001 estimate of 10,545 animals (Zeh 
and Punt, 2005), 0.21% of the Western North Pacific stock of 
approximately 938 humpback whales, 0.03% of the North Pacific stock of 
approximately 5,700 fin whales, and 0.19% of the Alaska stock of 
approximately 1,003 minke whales. The take estimates presented for 
bearded, ringed, spotted, and ribbon seals represent 0.09, 2.81, 0.22, 
and 0.01 percent of U.S. Arctic stocks of each species, respectively. 
These estimates represent the percentage of each species or stock that 
could be taken by Level B behavioral harassment if each animal is taken 
only once. In addition, the mitigation and monitoring measures 
(described previously in this document) proposed for inclusion in the 
IHA (if issued) are expected to reduce even further any potential 
disturbance to marine mammals.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the mitigation and monitoring 
measures, NMFS finds that Statoil's proposed 2010 open water marine 
seismic survey in the Chukchi Sea may result in the incidental take of 
small numbers of marine mammals, by Level B harassment only, and that 
the total taking from the marine surveys will have a negligible impact 
on the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

    NMFS has determined that Statoil's proposed 2010 open water marine 
seismic survey in the Chukchi Sea will not have an unmitigable adverse 
impact on the availability of species or stocks for taking for 
subsistence uses. This determination is supported by information 
contained in this document and Statoil's POC. Statoil has adopted a 
spatial and temporal strategy for its Chukchi Sea operations that 
should minimize impacts to subsistence hunters. Statoil will enter the 
Chukchi Sea far offshore, so as to not interfere with July hunts in the 
Chukchi Sea villages. After the close of the July beluga whale hunts in 
the Chukchi Sea villages, very little whaling occurs in Wainwright, 
Point Hope, and Point Lay. Although the fall bowhead whale hunt in 
Barrow will occur while Statoil is still operating (mid- to late-
September to October), Barrow is approximately 150 mi (241 km) east of 
the eastern boundary of the proposed marine seismic survey site. Based 
on these factors, Statoil's Chukchi Sea seismic survey is not expected 
to interfere with the fall bowhead harvest in Barrow. In recent years, 
bowhead whales have occasionally been taken in the fall by coastal 
villages along the Chukchi coast, but the total number of these animals 
has been small.
    Adverse impacts are not anticipated on sealing activities since the 
majority of hunts for seals occur in the winter and spring, when 
Statoil will not be operating. Additionally, most sealing activities 
occur much closer to shore than Statoil's proposed marine seismic 
survey area.
    Based on the measures described in Statoil's POC, the required 
mitigation and monitoring measures (described earlier in this 
document), and the project design itself, NMFS has determined that 
there will not be an unmitigable adverse impact on subsistence uses 
from Statoil's open water marine seismic survey in the Chukchi Sea.

Endangered Species Act (ESA)

    There are three marine mammal species listed as endangered under 
the ESA with confirmed or possible occurrence in the proposed project 
area: Bowhead whale, fin whale, and humpback whale. NMFS' Permits, 
Conservation and Education Division consulted with NMFS' Alaska 
Regional Office Division of Protected Resources under section 7 of the 
ESA on the issuance of an IHA to Statoil under section 101(a)(5)(D) of 
the MMPA for this activity. A Biological Opinion was issued on July 13, 
2010, which concludes that issuance of an IHA is not likely to 
jeopardize the continued existence of the fin, humpback, or bowhead 
whale. NMFS has issued an Incidental Take Statement under this 
Biological Opinion which contains reasonable and prudent measures with 
implementing terms and conditions to minimize the effects of take of 
listed species.

National Environmental Policy Act (NEPA)

    NMFS prepared an EA that includes an analysis of potential 
environmental effects associated with NMFS' issuance of an IHA to 
Statoil to take marine mammals incidental to conducting its

[[Page 49811]]

marine survey program in the Beaufort and Chukchi Seas during the 2010 
open water season. NMFS has finalized the EA and prepared a FONSI for 
this action. Therefore, preparation of an EIS is not necessary.

Authorization

    As a result of these determinations, NMFS has issued an IHA to 
Statoil to take marine mammals incidental to its 2010 open water marine 
seismic surveys in the Chukchi Sea, Alaska, provided the previously 
mentioned mitigation, monitoring, and reporting requirements are 
incorporated.

    Dated: August 6, 2010.
James H. Lecky,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2010-19962 Filed 8-12-10; 8:45 am]
BILLING CODE 3510-22-P