Federal Register, Volume 75 Issue 156 (Friday, August 13, 2010)

[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]

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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

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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.

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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

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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]
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