Taking Marine Mammals Incidental to Specified Activities; Seismic Surveys in the Beaufort and Chukchi Seas, 36044-36062 [E8-14393]
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36044
Federal Register / Vol. 73, No. 123 / Wednesday, June 25, 2008 / Notices
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric
Administration
RIN 0648–XD76
Taking Marine Mammals Incidental to
Specified Activities; Seismic Surveys
in the Beaufort and Chukchi Seas
National Marine Fisheries
Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA),
Commerce.
ACTION: Notice of receipt of application
and proposed incidental take
authorization; request for comments.
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AGENCY:
SUMMARY: NMFS has received an
application from Shell Offshore, Inc.
(SOI) and its contractor WesternGeco for
an Incidental Harassment Authorization
(IHA) to take small numbers of marine
mammals, by harassment, incidental to
conducting marine geophysical
programs, including deep seismic
surveys, on oil and gas lease blocks
located on Outer Continental Shelf
(OCS) waters in the Beaufort and
Chukchi Seas. Under the Marine
Mammal Protection Act (MMPA), NMFS
is requesting comments on its proposal
to issue an IHA to SOI and WesternGeco
to incidentally take, by Level B
harassment, small numbers of several
species of marine mammals during the
Arctic Ocean open-water seasons
between August 1, 2008 and July 31,
2009, incidental to conducting these
seismic surveys.
DATES: Comments and information must
be received no later than July 25, 2008.
ADDRESSES: Written comments on the
application should be addressed to Mr.
P. Michael Payne, Chief, Permits,
Conservation and Education Division,
Office of Protected Resources, National
Marine Fisheries Service, 1315 EastWest Highway, Silver Spring, MD
20910–3225, or by telephoning the
contact listed here. The mailbox address
for providing email comments is
PR1.XD76@noaa.gov. Comments sent
via e-mail, including all attachments,
must not exceed a 10–megabyte file size.
A copy of the application (containing
a list of the references used in this
document) may be obtained by writing
to this address or by telephoning the
contact listed here and are also available
at: https://www.nmfs.noaa.gov/pr/
permits/incidental.htm#iha.
A copy of the Minerals Management
Service (MMS) Final Programmatic
Environmental Assessment (Final PEA)
and the NMFS/MMS Draft
Programmatic Environmental Impact
Statement (Draft PEIS) are available at:
https://www.mms.gov/alaska/.
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Documents cited in this document
that are not available through standard
public library access methods, may be
viewed, by appointment, during regular
business hours at this address.
FOR FURTHER INFORMATION CONTACT:
Kenneth Hollingshead, Office of
Protected Resources, NMFS, (301) 713–
2289, or Brad Smith, NMFS, Alaska
Regional Office 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 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.
An authorization shall be granted if
NMFS finds that the taking will have a
negligible impact on the species or
stock(s) and will not have an
unmitigable adverse impact on the
availability of the species or stock(s) for
subsistence uses and the permissible
methods of taking and requirements
pertaining to the mitigation, monitoring
and reporting of such takings are set
forth. NMFS has defined ‘‘negligible
impact’’ in 50 CFR 216.103 as ’’...an
impact resulting from the specified
activity that cannot be reasonably
expected to, and is not reasonably likely
to, adversely affect the species or stock
through effects on annual rates of
recruitment or survival.’’
Section 101(a)(5)(D) of the MMPA
established an expedited process by
which citizens of the United States can
apply for an authorization to
incidentally take small numbers of
marine mammals by harassment. Except
with respect to certain activities not
pertinent here, the MMPA defines
‘‘harassment’’ as:
any act of pursuit, torment, or annoyance
which (i) has the potential to injure a marine
mammal or marine mammal stock in the wild
[Level A harassment]; or (ii) has the potential
to disturb a marine mammal or marine
mammal stock in the wild by causing
disruption of behavioral patterns, including,
but not limited to, migration, breathing,
nursing, breeding, feeding, or sheltering
[Level B harassment].
Section 101(a)(5)(D) establishes a 45day time limit for NMFS review of an
application followed by a 30-day public
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notice and comment period on any
proposed authorizations for the
incidental harassment of marine
mammals. Within 45 days of the close
of the comment period, NMFS must
either issue or deny the authorization.
Summary of Request
On October 16, 2007, NMFS received
an application from SOI for the taking,
by harassment, of several species of
marine mammals incidental to
conducting a marine seismic survey
program during the open water season
between August 1, 2008 and July 31,
2009 (referred to in this document as
2008/2009). SOI is planning a variety of
programs in the Chukchi and Beaufort
Seas during the 2008/2009 open water
seasons, including a: (1) Chukchi Sea
deep 3–D seismic survey; (2) Beaufort
Sea deep 3–D seismic survey; and (3)
Beaufort Sea marine surveys, which
includes three activities: (a) site
clearance and shallow hazards surveys;
(b) an ice-gouge survey; and (c) a strudel
scour survey.
The deep seismic survey components
of the program will be conducted from
WesternGeco’s vessel, M/V Gilavar.
Detailed specifications on this seismic
survey vessel are provided in
Attachment A of SOI’s IHA application.
These specifications include: (1)
complete descriptions of the number
and lengths of the streamers which form
the hydrophone arrays; (2) airgun size
and sound propagation properties; and
(3) additional detailed data on the M/V
Gilavar’s characteristics. In summary,
the M/V Gilavar will tow two source
arrays, comprising three identical
subarrays each, which will be fired
alternately as the ship progresses
downline in the survey area. The M/V
Gilavar will tow up to 6 streamer cables
up to 5.4 kilometers (km)(3.4 mi) long.
With this configuration each pass of the
M/V Gilavar can record 12 subsurface
lines spanning a swath of up to 360
meters (1181 ft). The seismic acquisition
vessel will be supported by the M/V
Gulf Provider, or a similar vessel. The
M/V Gulf Provider will serve as a crew
change, resupply, fueling support of
acoustic and marine mammal
monitoring, and seismic chase vessel. It
will not deploy seismic acquisition gear.
As SOI’s 2007 IHA for open water
seismic activities in the Chukchi and
Beaufort Seas is valid until August 1,
2008, this IHA request is intended,
therefore, for the open water seasons
between August 2, 2008 through July 31,
2009.
As marine mammals may be affected
by seismic and vessel noise, SOI has
requested an authorization under
section 101(a)(5)(D) of the MMPA to
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take marine mammals by Level B
harassment while conducting seismic
surveys and related activities.
Plan for Seismic Operations
In its application, SOI notes that it
plans for the M/V Gilavar to be in the
Chukchi Sea to begin seismic
acquisition data on or after July 20,
2008, move to the Beaufort Sea in midJuly through late October, and conclude
work in the Chukchi Sea around
November 15, 2008. For purposes of the
MMPA, the Chukchi and Beaufort seas
meet the definition of a ‘‘specific
geographic region’’ as defined under the
Act. As proposed, the 2008 seismic
survey effort will last a maximum of 100
days of active data acquisition
(excluding downtime due to weather
and other unforeseen delays). When ice
conditions permit or when SOI
determines to do so (at present, SOI
plans to work in the Chukchi Sea until
around September 25), the seismic and
associated vessels will transit to the
Beaufort Sea to conduct seismic
operation for part of the this 100-day
period. The proposed commencement
date of July 20th for starting seismic in
the Chukchi Sea is designed to ensure
that there will be no conflict with the
spring bowhead whale migration and
subsistence hunts conducted by Barrow,
Pt. Hope, or Wainwright or the beluga
subsistence hunt conducted by the
village of Pt. Lay in early July. The
approximate area of SOI’s seismic
survey operations are shown in Figure
1 in SOI’s IHA application.
3–D Deep Seismic Surveys
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Chukchi Sea 3–D Deep Seismic Surveys
SOI and its geophysical (seismic)
contractor, WesternGeco, propose to
conduct a marine geophysical (deep 3–
D seismic) survey program during open
water season on various MMS Outer
Continental Shelf (OCS) lease blocks in
the northern Chukchi Sea (see Figure 1
in SOI’s IHA application). The Chukchi
Sea 3–D Deep Seismic survey will be
conducted on leases obtained under
Lease Sale (LS) 193. The exact locations
where operations will occur within that
sale area were not known at the time of
SOI’s IHA application, but NMFS
presumes they will take place on lease
blocks obtained as a result of the sale.
However, in general SOI notes that the
seismic data acquisition will occur at
least 25 mi (40 km) offshore of the coast
and in waters with depths averaging
about 40 m (131 ft).
The deep 3–D seismic survey is
proposed to be conducted from
WesternGeco’s vessel M/V Gilavar,
described previously. Two ‘‘chase
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boats’’ will accompany the seismic
vessel. These two chase boats will
provide the following functions: (1) resupply, (2) marine mammal monitoring,
(3) ice scouting, and (4) general support
for the M/V Gilavar. The chase boat
vessels proposed for use in 2008 are the
M/V Theresa Marie and the M/V
Torsvik. These vessels will not deploy
any seismic gear. In addition, a crew
change vessel, the M/V Gulf Provider or
similar vessel and a landing craft, such
as the M/V Maxime or similar vessel,
will support the M/V Gilavar, and the
two chase boats in the Chukchi Sea. The
crew change vessel will be used to move
personnel and supplies from the seismic
vessel, and two chase boats to the
nearshore areas. In turn, the landing
craft will move personnel and supplies
from the crew change vessel, when it is
located in nearshore areas, to the beach
(most likely this will be at Barrow).
Lastly, the Marine Mammal Monitoring
and Mitigation Program (4MP) will have
a separate vessel for the proposed 2008
Program. The landing craft also will be
used to move personnel and equipment
from the 4MP vessel to the near shore
areas.
Beaufort Sea Deep 3–D Seismic Surveys
The same seismic vessel (M/V
Gilavar), seismic equipment, and chase
boats that are described for the Chukchi
Sea Deep 3–D Seismic survey, will be
used to conduct deep 3–D seismic
surveys in the central and eastern
Beaufort Sea (see Figure 2 in SOI’s IHA
application). The focus of this activity
will be on SOI’s existing leases, but
some activity in the Beaufort Sea may
occur outside of SOI’s existing leases.
The landing craft, which will be used to
move personnel and supplies from
vessels in the near shore to docking sites
will most likely use West Dock, or
Oliktok Dock. Smaller vessels such as
the Alaska Clean Seas (ACS) bay boats,
or similar vessels, may be used to assist
in the movement of people and supplies
and support of the 4MP in the Beaufort
Sea. The specific geographic region for
SOI’s deep seismic program in the
Beaufort Sea will be in OCS waters
including SOI leases beginning east of
the Colville River delta to west of the
village of Kaktovik (see Figure 2 in SOI’s
application). According to SOI’s IHA
application, the Beaufort Sea program is
planned to occur for a maximum of 60
days (excluding downtime due to
weather and unforeseen delays) during
open-water from mid-August to the end
of October; however, recent
communications with SOI indicates that
the Beaufort Sea seismic program will
not start until after September 25, 2008.
This timing of activities in the fall will
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avoid any significant conflict with the
Beaufort Sea bowhead whale
subsistence hunt conducted by the
Beaufort Sea villages, because it is
anticipated that the fall bowhead whale
hunt will have ended by that time.
Description of Marine 3–D Seismic Data
Acquisition
In the seismic method, reflected
sound energy produces graphic images
of seafloor and sub-seafloor features.
The seismic system consists of sources
and detectors, the positions of which
must be accurately measured at all
times. The sound signal comes from
arrays of towed energy sources. These
energy sources store compressed air
which is released on command from the
towing vessel. The released air forms a
bubble which expands and contracts in
a predictable fashion, emitting sound
waves as it does so. Individual sources
are configured into arrays. These arrays
have an output signal, which is more
desirable than that of a single bubble,
and also serve to focus the sound output
primarily in the downward direction,
which is useful for the seismic method.
This array effect also minimizes the
sound emitted in the horizontal
direction.
The downward propagating sound
travels to the seafloor and into the
geologic strata below the seafloor.
Changes in the acoustic properties
between the various rock layers result in
a portion of the sound being reflected
back toward the surface at each layer.
This reflected energy is received by
detectors called hydrophones, which are
housed within submerged streamer
cables which are towed behind the
seismic vessel. Data from these
hydrophones are recorded to produce
seismic records or profiles. Seismic
profiles often resemble geologic crosssections along the course traveled by the
survey vessel.
Description of WesternGeco’s Air-Gun
Array
SOI is proposing to use
WesternGeco’s 3147–in3 Bolt-Gun Array
for its 3–D seismic survey operations in
the Chukchi and Beaufort Seas.
WesternGeco’s source arrays are
composed of 3 identically tuned Boltgun sub-arrays operating at an air
pressure of 2,000 psi. In general, the
signature produced by an array
composed of multiple sub-arrays has the
same shape as that produced by a single
sub-array while the overall acoustic
output of the array is determined by the
number of sub-arrays employed.
The airgun arrangement for each of
the three 1049–in3 sub-array is detailed
in SOI’s application. As indicated in the
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application’s diagram, each sub-array is
composed of six tuning elements; two
2–airgun clusters and four single
airguns. The standard configuration of a
source array for 3–D surveys consists of
one or more 1049–in3 sub-arrays. When
more than one sub-array is used, as
here, the strings are lined up parallel to
each other with either 8 m or 10 m (26
or 33 ft) cross-line separation between
them. This separation was chosen so as
to minimize the areal dimensions of the
array in order to approximate point
source radiation characteristics for
frequencies in the nominal seismic
processing band. For the 3147–in3 array
the overall dimensions of the array are
15 m (49 ft) long by 16–m (52.5–ft)
wide.
Characteristics of Airgun Pulses
A discussion of the characteristics of
airgun pulses was provided in several
previous Federal Register documents
(see 69 FR 31792 (June 7, 2004) or 69
FR 34996 (June 23, 2004)) and is not
repeated here. Additional information
can be found in the NMFS/MMS Draft
PEIS (see ADDRESSES). Reviewers are
encouraged to read these earlier
documents for additional background
information.
Marine Surveys
SOI proposes to conduct marine
surveys (shallow hazards and other
activities) in the Beaufort and Chukchi
seas in 2008. Acoustic systems similar
to the ones proposed for use by SOI
during its planned marine surveys have
been described by NMFS previously
(see 66 FR 40996 (August 6, 2001), 70
FR 13466 (March 21, 2005)). NMFS
encourages readers to refer to these
documents for additional information
on these systems. A summary of SOI’s
planned activities is described next.
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Beaufort Sea Marine Surveys
SOI proposes to conduct three marine
survey activities in 2008 in the U.S.
Beaufort Sea: (1) Site Clearance and
Shallow Hazards (2) Ice Gouge Surveys,
and (3) Strudel Scour Surveys. Marine
surveys for site clearance and shallow
hazards, ice gouge, or strudel scour in
the Beaufort Sea can be accomplished
by the M/V Henry Christofferson. No
other vessels, such as chase boats, are
necessary to accomplish the proposed
marine survey work. Any necessary
crew changes or 4MP coordinated
activities under this activity will utilize
the same crew change, landing craft, or
4MP vessel mentioned under the
Beaufort Sea Deep 3–D Seismic survey.
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Site Clearance and Shallow Hazards
Marine surveys will include site
clearance and shallow hazards surveys
of potential exploratory drilling
locations. These surveys gather data on:
(1) bathymetry, (2) seabed topography
and other seabed characteristics (e.g.,
boulder patches), (3) potential
geohazards (e.g., shallow faults and
shallow gas zones), and (4) the presence
of any archeological features (e.g.,
shipwrecks).
The focus of this activity will be on
SOI’s existing leases in the central and
eastern Beaufort Sea, but some activity
may occur outside of SOI’s existing
leases. Actual locations of site clearance
and shallow hazard surveys have not
been definitively set as of the date of
this publication, although they will
occur within the area outlined in Figure
2 of SOI’s IHA application.
The vessel that SOI expects to use for
the site clearance and shallow hazards
surveys is the M/V Henry Christofferson,
which is a diesel-powered tug as
described in Attachment A to SOI’s IHA
application. SOI proposes to use the
following acoustic instrumentation, (or
similar equipment) during this work.
This is the same equipment as was used
on the M/V Henry Christofferson during
2007:
(1) Dual frequency subbottom profiler
Datasonics CAP6000 Chirp II (2 to7
kiloHertz [kHz] or 8 to 23 kHz) or
similar;
(2) Medium penetration subbottom
profiler, Datasonics SPR–1200 Bubble
Pulser (400 (hertz [Hz]) or similar;
(3) High resolution multi-channel 2D
system, 20 cubic inches (in3) (2 by 10)
gun array (0 to 150 Hz) or similar;
(4) Multi-beam bathymetric sonar,
Seabat 8101 (240 Hz); or similar; and
(5) Side-scan sonar system, Datasonics
SIS–1500 (190 to 210 kHz) or similar.
Ice Gouge Survey
Ice gouge surveys are a type of marine
survey to determine the depth and
distribution of ice gouges in the sea bed.
Ice gouge is created by ice keels which
project from the bottom of moving ice
that gouge into seafloor sediment.
Remnant ice gouge features are mapped
to aid in predicting the prospect of,
orientation, depth, and frequency of
future ice gouge. These surveys will
focus on the potential, prospective
pipeline corridor between the Sivulliq
Prospect in Camden Bay and the
nearshore Point Thomson area. The
Sivulliq area will be surveyed to gather
geotechnical and seafloor hazard
information as well as data on ice
gouges.
SOI proposes that the acoustic
instrumentation described previously in
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this document (or something similar)
will be used, namely multi-beam
bathymetric sonar, side scan sonar and
subbottom profiling. Actual locations of
the ice gouge surveys have not been
definitively set as of the date of this
publication, although these will occur
within the area outlined in Figure 2 of
SOI’s IHA application. There are also
some platform siting lines proposed,
which would employ a high resolution
multi-channel 2D system, 20 cubic
inches (in3) (2 by 10) airgun array (0 to
150 Hz) or similar system.
Strudel Scour Survey
During the early melt on the North
Slope, the rivers begin to flow and
discharge water over the coastal sea ice
near the river deltas. That water rushes
down holes in the ice (‘‘strudels’’) and
scours the seafloor. These erosional
areas are called ‘‘strudel scours’’.
Information on these features is required
for prospective pipeline planning. Two
proposed activities are required to
gather this information.
First, an aerial survey will be
conducted via helicopter overflights
during the melt to locate the strudels;
and strudel scour marine surveys to
gather bathymetric data. The overflights
investigate possible sources of overflood
water and will survey local streams that
discharge in the vicinity of Point
Thomson including the Staines River,
which discharges to the east into
Flaxman Lagoon and the Canning River,
which discharges to the east directly
into the Beaufort Sea. These helicopter
overflights were scheduled to occur
during late May/early June 2008 and,
weather permitting, should take no
more than four days. There are no
planned landings during these
overflights other than at the Deadhorse
or Kaktovik airports.
Second, areas that have strudel scour
identified during the aerial survey will
be verified and surveyed with a marine
vessel after the breakup of nearshore ice.
This proposed activity is not anticipated
to take more than 5 days to conduct.
The operation is conducted in the
shallow water areas near the coast in the
vicinity of Point Thomson. The vessel
has not been contracted; however, it is
anticipated that it will be the dieselpowered R/V Annika Marie. This vessel
will use the following equipment:
(1) Multi-beam bathymetric sonar,
Seabat 8101 (240 Hz); or similar sonar;
and
(2) Side-scan sonar system, Datasonics
SIS–1500 (190 to 210 kHz) or similar
sonar.
The multi-beam bathymetric sonar
and the side-scan sonar systems both
operate at frequencies greater than 180
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kHz, the highest frequency considered
by knowledgeable marine mammal
biologists to be of possible influence to
marine mammals. Because no taking of
marine mammals will occur from this
equipment, no measurements of those
two sources are planned by SOI, and no
exclusion zones for seals or whales
would be established during operation
of those two sources. The acoustic
instrumentation used on the seismic
vessels are described in SOI’s IHA
application.
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Chukchi Sea Marine Surveys
Marine surveys will include site
clearance and shallow hazards surveys
of potential exploratory drilling
locations as required by MMS
regulations. These surveys gather data
on: (1) bathymetry, (2) seabed
topography and other seabed
characteristics (e.g., boulder patches),
(3) potential geohazards (e.g., shallow
faults and shallow gas zones), and (4)
the presence of any archeological
features (e.g., shipwrecks). Marine
surveys for site clearance and shallow
hazards can be accomplished by one
vessel with acoustic sources. No other
vessels, such as chase boats, are
necessary to accomplish the proposed
work. Any necessary crew changes or
4MP coordinated activities under this
activity will utilize the same crew
change, landing craft, or 4MP vessel
mentioned under the Chukchi Sea deep
3D seismic surveys.
The Chukchi Sea marine surveys will
be conducted by SOI on leases acquired
in OCS LS 193. Site clearance surveys
are confined to small specific areas
within OCS blocks. Actual locations of
site clearance and shallow hazard
surveys have not been definitively set as
of the date of SOI’s IHA application,
although these will occur within the
general area outlined in Figure 1 in
SOI’s IHA application. Before the
commencement of operations, survey
location information will be supplied to
NMFS, MMS, other agencies and
affected members of the public as it
becomes available. SOI has not
contracted for a vessel at the time of
publication of this document.
Additional Information
A detailed description of the work
proposed by SOI for the open-water
seasons of 2008/2009 is contained in
SOI’s application which is available for
review (see ADDRESSES). Also, a
description of SOI’s data acquisition
program proposed for the 2008/2009
season, and WesternGeco’s air-gun array
to be employed during 2008/2009 has
been provided in previous IHA notices
on SOI’s seismic program (see 71 FR
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26055, May 3, 2006; 71 FR 50027,
August 24, 2006).
Description of Habitat and Marine
Mammals Affected by the Activity
A detailed description of the Beaufort
and Chukchi sea ecosystems and their
associated marine mammal populations
can be found in the NMFS/MMS Draft
PEIS and the MMS Final Programmatic
Environmental Assessment (Final PEA)
on Seismic Surveys (see ADDRESSES for
availability) and also in several other
documents (e.g., MMS, 2007 Final EIS
for Chukchi Sea Planning Area: Oil and
Gas Lease Sale 193 and Seismic
Surveying Activities in the Chukchi Sea.
MMS 2007–026).
Marine Mammals
The Beaufort/Chukchi Seas support a
diverse assemblage of marine mammals,
including bowhead whales, gray whales,
beluga whales, killer whales, harbor
porpoise, ringed seals, spotted seals,
bearded seals, walrus and polar bears.
These latter two species are under the
jurisdiction of the U.S. Fish and
Wildlife Service (USFWS) and are not
discussed further in this document.
Descriptions of the biology and
distribution of the marine mammal
species under NMFS’ jurisdiction can be
found in SOI’s IHA application, the
2007 NMFS/MMS Draft PEIS on Arctic
Seismic Surveys, and the MMS 2006
Final PEA on Arctic Seismic Surveys.
Information on these marine mammal
species can also be found in NMFS
Stock Assessment Reports (SARS). The
2007 Alaska SARS document is
available at: https://www.nmfs.noaa.gov/
pr/pdfs/sars/ak2007.pdf. Please refer to
those documents for information on
these species.
Potential Effects of Seismic Surveys on
Marine Mammals
Disturbance by seismic noise is the
principal means of taking by this
activity. Support vessels and aircraft
may provide a potential secondary
source of noise. The physical presence
of vessels and aircraft could also lead to
non-acoustic effects on marine
mammals involving visual or other cues.
As outlined in previous NMFS
documents, the effects of noise on
marine mammals are highly variable,
and can, in general, be categorized as
follows (based on Richardson et al.,
1995):
(1) The noise may be too weak to be
heard at the location of the animal (i.e.,
lower than the prevailing ambient noise
level, the hearing threshold of the
animal at relevant frequencies, or both);
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(2) The noise may be audible but not
strong enough to elicit any overt
behavioral response;
(3) The noise may elicit reactions of
variable conspicuousness and variable
relevance to the well being of the
marine mammal; these can range from
temporary alert responses to active
avoidance reactions such as vacating an
area at least until the noise event ceases;
(4) Upon repeated exposure, a marine
mammal may exhibit diminishing
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;
(5) Any anthropogenic noise that is
strong enough to be heard has the
potential to reduce (mask) the ability of
a marine mammal to hear natural
sounds at similar frequencies, including
calls from conspecifics, and underwater
environmental sounds such as surf
noise;
(6) If mammals remain in an area
because it is important for feeding,
breeding or some other biologically
important purpose even though there is
chronic exposure to noise, it is possible
that there could be noise-induced
physiological stress; this might in turn
have negative effects on the well-being
or reproduction of the animals involved;
and
(7) Very strong sounds have the
potential to cause temporary or
permanent reduction in hearing
sensitivity. In terrestrial mammals, and
presumably marine mammals, received
sound levels must far exceed the
animal’s hearing threshold for there to
be any temporary threshold shift (TTS)
in its hearing ability. For transient
sounds, the sound level necessary to
cause TTS is inversely related to the
duration of the sound. Received sound
levels must be even higher for there to
be risk of permanent hearing
impairment. In addition, intense
acoustic or explosive events may cause
trauma to tissues associated with organs
vital for hearing, sound production,
respiration and other functions. This
trauma may include minor to severe
hemorrhage.
Effects of Seismic Survey Sounds on
Marine Mammals
Behavioral Effects
In its IHA application, SOI states that
the only anticipated impacts to marine
mammals associated with noise
propagation from vessel movement and
seismic airgun operations would be the
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temporary and short term displacement
of whales and seals from within
ensonified zones produced by such
noise sources. Any impacts on the
whale and seal populations of the
Beaufort and Chukchi Seas activity
areas are likely to be short-term and
transitory arising from the temporary
displacement of individuals or small
groups from locations they may occupy
at the times they are exposed to seismic
sounds between the 160- to 190–dB
received levels. In the case of bowhead
whales however, that displacement
might well take the form of a deflection
of the swim paths of migrating
bowheads away from (seaward of)
received noise levels lower than 160 db
(Richardson et al., 1999). Moreover, it is
not presently known at what distance
after passing the seismic source that
bowheads will return to their previous
migration route. However, NMFS does
not believe that this offshore deflection
is biologically significant (although it
might be significant for purposes of
subsistence hunting, as discussed later)
as the bowhead migration is believed to
remain within the general bowhead
whale migratory corridor in the U.S.
Beaufort Sea, which varies annually
based on environmental factors.
SOI cites Richardson and Thomson
[eds]. (2002) to support its contention
that there is no conclusive evidence that
exposure to sounds exceeding 160 dB
have displaced bowheads from feeding
activity. NMFS notes that, in 2006,
observations conducted onboard a
seismic vessel operating in the Canadian
Beaufort Sea found that feeding
bowhead whales were not observed to
respond to seismic sounds at levels of
160 dB or lower.
Results from the 1996–1998 BP and
Western Geophysical seismic
monitoring programs in the Beaufort Sea
indicate that most fall migrating
bowheads deflected seaward to avoid an
area within about 20 km (12.4 mi) of an
active nearshore seismic operation, with
the exception of a few closer sightings
when there was an island or very
shallow water between the seismic
operations and the whales (Miller et al.,
1998, 1999). The available data do not
provide an unequivocal estimate of the
distance (and received sound levels) at
which approaching bowheads begin to
deflect, but this may be on the order of
35 km (21.7 mi).
When the received levels of noise
exceed some threshold, cetaceans will
show behavioral disturbance reactions.
The levels, frequencies, and types of
noise that will elicit a response vary
between and within species,
individuals, locations, and seasons.
Behavioral changes may be subtle
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alterations in surface, respiration, and
dive cycles. More conspicuous
responses include changes in activity or
aerial displays, movement away from
the sound source, or complete
avoidance of the area. The reaction
threshold and degree of response also
are related to the activity of the animal
at the time of the disturbance. Whales
engaged in active behaviors, such as
feeding, socializing, or mating, appear
less likely than resting animals to show
overt behavioral reactions, unless the
disturbance is perceived as directly
threatening.
Masking
Although NMFS believes that some
limited masking of low-frequency
sounds (e.g., whale calls) is a possibility
during seismic surveys, the intermittent
nature of seismic source pulses (1
second in duration every 16 to 24
seconds (i.e., less than 7 percent duty
cycle)) will limit the extent of masking.
Bowhead whales are known to continue
calling in the presence of seismic survey
sounds, and their calls can be heard
between seismic pulses (Greene et al.,
1999, Richardson et al., 1986). Masking
effects are expected to be absent in the
case of belugas, given that sounds
important to them are predominantly at
much higher frequencies than are airgun
sounds.
Injury and Mortality
NMFS and SOI believe that there is no
evidence that bowheads or other marine
mammals exposed to seismic sounds in
the Arctic have incurred an injury to
their auditory mechanisms. While it is
not positively known whether the
hearing systems of marine mammals
very close to an airgun would be at risk
of temporary or permanent hearing
impairment, Richardson et al. (1995)
notes that TTS is a theoretical
possibility for animals within a few
hundred meters of the source. More
recently, scientists have determined that
the received level of a single seismic
pulse might need to be ∼210 dB re 1 µPa
rms (∼221–226 dB pk-pk) in order to
produce brief, mild TTS. Exposure to
several seismic pulses at received levels
near 200–205 dB (rms) might result in
slight TTS in a small odontocete,
assuming the TTS threshold is a
function of the total received pulse
energy. Seismic pulses with received
levels of 200–205 dB or more are
usually restricted to a radius of no more
than 200 m (656 ft) around a seismic
vessel operating a large array of airguns.
For baleen whales, there are no data,
direct or indirect, on levels or properties
of sound that are required to induce
TTS. However, according to SOI, there
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is a strong likelihood that baleen whales
(i.e., bowheads, gray whales and
humpback whales) would avoid the
approaching airguns (or vessel) before
being exposed to levels high enough for
there to be any possibility of onset of
TTS.
For pinnipeds, information indicates
that for single seismic impulses, sounds
would need to be higher than 190 dB
rms for TTS to occur while exposure to
several seismic pulses indicates that
some pinnipeds may incur TTS at
somewhat lower received levels than do
small odontocetes exposed for similar
durations. This indicates to NMFS that
the 190–dB safety zone (see Mitigation
and Monitoring later in this document)
provides a sufficient buffer to prevent
permanent threshold shift (PTS) in
pinnipeds.
A marine mammal within a radius of
≤100 m (≤328 ft) around a typical large
array of operating airguns may be
exposed to a few seismic pulses at
received levels of ≥205 dB, and possibly
more pulses if the marine mammal
moved with the seismic vessel. 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.
However, as scientists are reluctant to
cause injury to a marine mammals, 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. Given the possibility
that mammals close to an airgun array
might incur TTS, there has been further
speculation about the possibility that
some individuals occurring very close to
airguns might incur PTS. Single or
occasional occurrences of mild TTS are
not indicative of permanent auditory
damage in terrestrial mammals.
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. Acousticians are in
general agreement that a temporary shift
in hearing threshold of up to 40 dB due
to moderate exposure times is fully
recoverable and does not involve tissue
damage or cell loss. Liberman and
Dodds (1987) state, ’’... acute threshold
shifts as large as 60 dB are routinely
seen in ears in which the surface
morphology of the stereocilia is
perfectly normal.’’ (Stereocilia are the
sensory cells responsible for the
sensation of hearing.). In the chinchilla,
no cases of TTS involve the loss of
stereocilia, but all cases of PTS do
(Ahroon et al., 1996). Cell death clearly
qualifies as Level A harassment (injury)
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under the MMPA. Because there is no
cell death with modest (up to 40 dB)
TTS, such losses of sensitivity
constitute a temporary impairment but
not an injury, further supporting NMFS’
precautionary approach that
establishment of seismic airgun
shutdown at 180 dB for cetaceans and
190 dB for pinnipeds, will prevent
auditory injury to marine mammals by
seismic airgun sounds.
NMFS notes that planned monitoring
and mitigation measures (described later
in this document) have been designed to
avoid sudden onsets of seismic pulses at
full power, to detect marine mammals
occurring near the array, and to avoid
exposing them to sound pulses that
have any possibility of causing hearing
impairment. Moreover, NMFS does not
expect that any marine mammals will be
seriously injured or killed during SOI’s
seismic survey activities, even if some
animals are not detected prior to
entering the 180–dB and 190–dB
isopleths (safety zones) for cetaceans
and pinnipeds, respectively. These
criteria were set to approximate a level
below where Level A harassment (i.e.,
defined as ‘‘any act of pursuit, torment
or annoyance which has the potential to
injure a marine mammal or marine
mammal stock in the wild’’) from
acoustic sources was believed to begin.
Because, a decade or so ago, scientists
did not have information on where PTS
might occur in marine mammals, the
High Energy Seismic Survey (HESS)
workshop (HESS, 1997, 1999) set the
level to prevent injury to marine
mammals at 180 dB. NMFS concurred
and determined that TTS, which is the
mildest form of hearing impairment that
can occur during exposure to a strong
sound, may occur at these levels (180
dB for cetaceans, 190 dB for pinnipeds).
When a marine mammal experiences
TTS, the hearing threshold rises and a
sound must be stronger in order to be
heard. TTS can last from minutes or
hours to (in cases of strong TTS) days.
For sound exposures at or somewhat
above the TTS threshold, hearing
sensitivity recovers rapidly after
exposure to the noise ends. Few data on
sound levels and durations necessary to
elicit mild TTS have been obtained for
marine mammals, and none of the
published data concern TTS elicited by
exposure to multiple pulses of sound.
Strandings
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
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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 74905 (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 June,
2008 stranding of 30–40 melon-headed
whales (Peponocephala spp), off
Madagascar that appears to be
associated with seismic surveys is
currently under investigation. One
report indicates that the stranding began
prior to seismic surveys starting.
It should be noted that marine
mammal strandings recorded in the
Beaufort and Chukchi seas do not
appear to be related to seismic surveys.
Finally, if bowhead and gray whales
react to sounds at very low levels by
making minor course corrections to
avoid seismic noise and mitigation
measures require SOI to ramp-up the
seismic array to avoid a startle effect,
strandings are unlikely to occur in the
Arctic Ocean. As a result, NMFS does
not expect any marine mammals will
incur serious injury, mortality or
strandings in the Arctic Ocean.
Potential Impacts on Affected Species
and Stocks of Marine Mammals
According to SOI, the only
anticipated impacts to marine mammals
associated with SOI’s seismic activities
with respect to noise propagation are
from vessel movements and seismic air
gun operations. SOI states that these
impacts would be temporary and short
term displacement of seals and whales
from within ensonified zones produced
by such noise sources. Any impacts on
the whale and seal populations of the
Beaufort and Chukchi Sea activity areas
are likely to be short term and transitory
arising from the temporary
displacement of individuals or small
groups from locations they may occupy
at the times they are exposed to seismic
sounds at the 160–190 dB (or higher)
received levels. As noted elsewhere, it
is highly unlikely that animals will be
exposed to sounds of such intensity and
duration as to physically damage their
auditory mechanisms. In the case of
bowhead whales that displacement
might well take the form of a deflection
of the swim paths of migrating
bowheads away from (seaward of)
received noise levels greater than 160 db
(Richardson et al., 1999). There is no
evidence that bowheads so exposed
have incurred injury to their auditory
mechanisms. Also, there is no evidence
that seals are more than temporarily
displaced from ensonified zones and no
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36049
evidence that seals have experienced
physical damage to their auditory
mechanisms even within ensonified
zones.
During the period of seismic
acquisition in the Chukchi and Beaufort
seas, most marine mammals are
expected to be dispersed throughout the
area. Bowhead whales are expected to
be concentrated in the Canadian
Beaufort Sea during much of this time,
where they are not expected to be
affected by SOI’s seismic program. The
peak of the bowhead whale migration
through the Beaufort and Chukchi seas
typically occurs in late August through
October, and efforts to reduce potential
impacts during this time will be
addressed with the actual start of the
migration and through discussions with
the affected whaling communities. In
the Chukchi Sea, the timing of seismic
activities will take place while the
whales are widely distributed and
would be expected to occur in very low
numbers within the seismic activity
area. If SOI conducts seismic surveys in
late September or October in the
Beaufort or Chukchi Sea, bowheads may
travel in proximity to the seismic survey
activity areas and hear sounds from
vessel traffic and seismic activities, of
which some might be displaced by the
planned activities.
The reduction of potential impacts
during the fall bowhead whale
migratory period will be addressed
through discussions with the whaling
communities. Starting in late August
bowheads may travel in proximity to
SOI’s planned Beaufort Sea seismic
activity areas and may hear sounds from
vessel traffic and seismic activities, of
which some might be displaced seaward
by the planned activities. However, at
the present time, SOI expects to
significantly reduce its period of seismic
operations in the Beaufort Sea by
remaining in the Chukchi Sea until midSeptember, entering the Beaufort Sea
only after the fall subsistence hunt has
concluded and after a significant
portion of the bowhead whales would
have left the Canadian Beaufort Sea on
their westward migration to the Chukchi
Sea.
In addition, although there was
apparently a period of concentrated
feeding in the central Beaufort Sea in
September 2007, feeding does not
normally appear to be an important
activity by bowheads migrating through
the eastern and central part of the
Alaskan Beaufort Sea or the Chukchi
Sea in most years. Sightings of bowhead
whales occur in the summer near
Barrow (Moore and DeMaster, 2000),
and there are suggestions that certain
areas near Barrow are important feeding
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grounds. In addition, a few bowheads
can be found in the Chukchi and Bering
Seas during the summer and Rugh et al.
(2003) suggests that this may be an
expansion of the western Arctic stock,
although more research is needed. In the
absence of important feeding areas, the
potential diversion of a small number of
bowheads away from seismic activities
is not expected to have any significant
or long-term consequences for
individual bowheads or their
population.
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Effects on Individual Arctic Ocean
Marine Mammal Species
In order to facilitate the reader’s
understanding of the knowledge of
impacts of impulsive noise on the
principal marine mammal species that
are expected to be affected by SOI’s
proposed seismic survey program,
NMFS has previously provided a
summary of potential impacts on the
bowhead, gray, and beluga whales and
the ringed, largha and bearded seals.
This information can be found in the
Federal Register (72 FR 31553, June 7,
2007). Information on impacts on
marine mammals by seismic activities
can also be found in SOI’s IHA
application.
Numbers of Marine Mammals Expected
to Be Harassed by Seismic Survey
Activities
The methodology used by SOI to
estimate incidental take by harassment
by seismic and the numbers of marine
mammals that might be affected in the
proposed seismic acquisition activity
area in the Chukchi and Beaufort seas
has been presented in SOI’s 2008 IHA
application.
In its application, SOI provides
estimates of the number of potential
‘‘exposures’’ to sound levels equal to or
greater than 160 dB re 1 µPa (rms).
NMFS clarifies here that, except
possibly for bowhead whales,
calculations of the number of exposures
by SOI, does not necessarily indicate
that this is the number of Level B
harassments that SOI’s seismic activity
will take. First, exposure estimates do
not take into account variability
between species or within a species by
activity, age or sex. What this means is
that not all animals are expected to react
at the same level as its conspecifics, and
all species are not expected to react at
the same level, as some species in the
Arctic will respond to sounds
differently, if at all, depending upon
whether or not they have good hearing
in the same frequency range as seismic.
Second, NMFS believes that SOI’s use of
the maximum density estimates for its
requested take authorization (see IHA
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application and references for details) is
overly cautious as it tends to inflate
harassment take estimates to an
unreasonably high number and is not
based on good empirical science. NMFS
believes that these inflated numbers
have been provided and used by SOI for
its Level B harassment take request in
an abundance of caution because they
present a worst-case estimate. NMFS, on
the other hand prefers to use the average
density estimate numbers provided in
Tables 6–1 through 6–5 in SOI’s IHA
application as these are the more
realistic and scientifically supportable
estimates. NMFS notes, for example,
that the most comprehensive survey
data set on ringed and bearded seals
from the central and eastern Beaufort
Sea was conducted on offshore pack ice
in late spring. Density estimates of
ringed and bearded seals were based on
counts of seals on the ice during this
survey, not in open water where seismic
surveys are conducted. Consequently,
the density and potential take
(exposure) numbers for seals in the
Beaufort and Chukchi seas will likely
overestimate the number of seals that
could be encountered and/or exposed to
seismic airguns because only animals in
the water near the survey area would be
exposed to seismic and site clearance
activity sound sources. Because seals
would be more widely dispersed while
in open water, NMFS presumes that
animal densities would be less than
when seals are concentrated on and near
the ice. Compounding that error, SOI
calculated the maximum density for
seals as 4 times the average density,
which NMFS does not believe is
supported by the best available science.
The estimates for marine mammal
‘‘exposure’’ are based on a consideration
of the number of marine mammals that
might be appreciably disturbed during
approximately 7974 km (4955 mi) of full
3D seismic surveys and approximately
4294 km (2668 mi) of mitigation gun
activity in the Chukchi Sea and by
approximately 4784 km (2973 mi) of full
3D seismic surveys and approximately
2576 km (1600 mi) of mitigation gun (a
single small airgun used when the
airgun array is not active to alert marine
mammals to the presence of the survey
vessel) activity in the Beaufort Sea. In
addition to the 3D seismic program, the
shallow hazards surveys using a 2 10 in3
airgun array will be performed along
approximately 1237 km (769 mi) in the
Beaufort Sea and approximately 432 km
(268 mi) in the Chukchi Sea.
NMFS further notes that the close
spacing of neighboring tracklines within
the planned 3D seismic survey areas
results in a limited amount of total area
of the Chukchi and Beaufort seas being
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exposed to sounds ≥ 160 dB while much
of the survey area is exposed repeatedly.
This means that the number of nonmigratory cetaceans and pinnipeds
exposed to seismic sounds would be
less than if the seismic vessel conducted
straight line transects of the sea without
turning and returning on a nearby,
parallel track. However, these animals
may be exposed several times before the
seismic vessel moves to a new site. In
that regard, NMFS notes that the
methodology used by SOI in its
‘‘exposure’’ calculations is more valid
for seismic surveys that transect long
distances, for those surveys that ‘‘mow
the lawn’’ (that is, remain within a
relatively small area, transiting back and
forth while shooting seismic). In such
situations, the Level B harassment
numbers tend to be highly inflated, if
each ‘‘exposure’’ is calculated to be a
different animal and not, as here, a
relatively small number of animals
residing in the area and being
‘‘exposed’’ to seismic sounds several
times during the season. As a result,
NMFS believes that SOI’s estimated
number of individual exposures does
not account for multiple exposures of
the same animal (principally nonmigratory pinnipeds) instead of single
animal exposures as the survey
conducts a number of parallel transects
of the same area (sometimes called
bostrophodontical surveys) and the fact
that the mitigation procedures would
serve to reduce exposures to affected
marine mammals.
As mentioned previously, 3D seismic
airgun arrays are composed of
identically tuned Bolt-gun sub-arrays
operating at 2,000 psi. In general, the
signature produced by an array
composed of multiple sub-arrays has the
same shape as that produced by a single
sub-array while the overall acoustic
output of the array is determined by the
number of sub-arrays employed. The
gun arrangement for the 1,049 square
inches (in2) sub-array is detailed below
and is comprised of three subarrays
comprising a total 3,147 in2 sound
source. The anticipated radii of
influence of the bathymetric sonars and
pinger are less than those for the air gun
configurations described in Attachment
A in SOI’s IHA application. It is
assumed that, during simultaneous
operations of those additional sound
sources and the air gun(s), any marine
mammals close enough to be affected by
the sonars or pinger would already be
affected by the air gun(s). In this event,
SOI believes that marine mammals are
not expected to exhibit more than shortterm and inconsequential responses,
and such responses have not been
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considered to constitute ‘‘taking’’
therefore, potential taking estimates
only include noise disturbance from the
use of air guns. The specifications of the
equipment, including site clearance
activities, to be used and areas of
ensonification are described more fully
in SOI’s IHA application (see
Attachment B in SOI’s IHA application).
Cetaceans
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For belugas and gray whales, in both
the Beaufort and Chukchi Seas and
bowhead whales in the Chukchi Sea,
Moore et al. (2000b and c) offer the most
current data to estimate densities during
summer. Density estimates for bowhead
whales in the Beaufort Sea were
updated by information provided by
Miller et al. (2002).
Tables 6–1 and 6–2 (Chukchi Sea) and
Tables 6–3 and 6–4 (beluga and
bowhead: Beaufort Sea) provide density
estimates for the summer and fall,
respectively. Table 6–5 provides a
summary of the expected densities for
cetaceans (other than bowheads and
belugas) and pinnipeds during all
seasons in the Beaufort Sea. The number
of different individuals of each species
potentially exposed to received levels
≥160 dB re 1 µPa (rms) within each
survey region, time period, and habitat
zone was estimated by multiplying the
expected species density, by the
anticipated area to be ensonified to the
160–dB level in the survey region, time
period, and habitat zone to which that
density applies.
The numbers of ‘‘exposures’’ were
then summed by SOI for each species
across the survey regions, 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 µPa (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.
For the full–3D airgun array, the cross
track distance is 2 the 160–dB radius
which was measured in 2007 as 8.1 km
(5.0 mi) in the Chukchi Sea and 13.4 km
(8.3 mi) in the Beaufort Sea. The
mitigation gun’ 160–dB radius was
measured at 1370 m (4495 ft) in the
Chukchi Sea and Beaufort seas. For
shallow hazards surveys to be
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Jkt 214001
performed by the Henry Christofferson,
the 160–dB radius measured in 2007
was equal to 621 m (2037 ft). Using
these distances, SOI estimates that the
area ensonified in the Chukchi Sea is
approximately 15,000 km2 and
approximately 10,100 km2 in the
Beaufort Sea.
The estimated numbers of potential
marine mammal ‘‘exposures’’ by SOI’s
surveys are presented in Tables 6–6 for
the summer/fall period in the Chukchi
Sea, Table 6–7 for bowhead and beluga
whales in the U.S. Beaufort Sea and in
Table 6–8 for marine mammals (other
than bowheads and belugas) in the
Beaufort Sea. Table 1 in this document
(Table 6–9 in the IHA application)
summarizes these exposure estimates
based on the 160–dB re 1 µPa (rms)
criteria for cetaceans exposed to
impulse sounds (such as seismic).
SOI’s estimates show that the
bowhead whale is the only endangered
marine mammal expected to be exposed
to noise levels ≥ 160 dB unless, as
expected during the fall migratory
period, bowheads avoid the
approaching survey vessel before the
received levels reach 160 dB. Migrating
bowheads are likely to take avoidance
measures, though many of the bowheads
engaged in other activities, particularly
feeding and socializing, probably will
not. SOI’s estimate of the number of
bowhead whales potentially exposed to
≥160 dB is 1540 animals (9 in the
Chukchi Sea and 1531 in the Beaufort
Sea (see Table 1)). Two other
endangered cetacean species that may
be encountered in the northern
Chukchi/western Beaufort Sea area, the
fin whale and humpback whale, are
estimated by SOI to have two exposures
each in the Chukchi Sea. However,
NMFS believes that at least for the fin
whale, no animals would be so exposed
given their low ‘‘average’’ estimates of
densities in the area.
Most of the cetaceans exposed to
seismic sounds with received levels
≥160 dB would involve bowhead, gray,
and beluga whales, and the harbor
porpoise. Average estimates of the
number of exposures of cetaceans by 3D
seismic surveys (other than bowheads),
in descending order, are beluga (298),
gray whale (183), and harbor porpoise
(58). The regional breakdown of these
numbers is shown in Tables 6–6 to 6–
8. Estimates for other species are lower
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(Table 6–9). These estimates are also
provided in Table 1 in this Federal
Register notice.
Pinnipeds
Ringed, spotted, and bearded seals are
all associated with sea ice, and most
census methods used to determine
density estimates for pinnipeds are
associated with counting the number of
seals hauled out on ice. Correction
factors have been developed for most
pinniped species that address biases
associated with detectability and
availability of a particular species.
Although extensive surveys of ringed
and bearded seals have been conducted
in the Beaufort Sea, the majority of the
surveys have been conducted over the
landfast ice and few seal surveys have
been in open water. The most
comprehensive survey data set on
ringed seals (and bearded seal) from the
central and eastern Beaufort Sea was
conducted on offshore pack ice in late
spring (Kingsley, 1986). It is important
to note that all proposed activities will
be conducted during the open-water
season and density estimates used here
were based on counts of seals on ice.
Therefore, densities and potential take
numbers will overestimate the numbers
of seals that would likely be
encountered and/or exposed because
only the animals in the water would be
exposed to the seismic and clearance
activity sound sources.
The ringed seal is the most
widespread and abundant pinniped in
ice-covered arctic waters and ringed
seals are expected to account for the
vast majority of marine mammals
expected to be encountered, and hence
exposed to airgun sounds with received
levels ≥160 dB re 1 µPa (rms) during
SOI’s seismic survey. The average
estimate is that 13,256 ringed seals
might be exposed to seismic sounds
with received levels ≥160 dB. Two
additional pinniped species (other than
the Pacific walrus) are expected to be
encountered. They are the bearded seal
(592 exposures), and the spotted seal
(422 exposures)(see Table 1 in this
document or Table 6–9 in the IHA
application). The spotted seal and
ribbon seal are unlikely to be
encountered during SOI’s seismic
surveys.
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TABLE 1.SUMMARY OF THE NUMBER OF POTENTIAL EXPOSURES OF MARINE MAMMALS TO RECEIVED SOUND LEVELS IN
THE WATER OF ≥160 DB DURING SOI’S PROPOSED SEISMIC PROGRAM IN THE CHUKCHI SEA AND BEAUFORT SEA,
ALASKA, JULY - NOVEMBER, 2008. NOT ALL MARINE MAMMALS WILL CHANGE THEIR BEHAVIOR WHEN EXPOSED TO
THESE SOUND LEVELS, ALTHOUGH SOME MIGHT ALTER THEIR BEHAVIOR SOMEWHAT WHEN LEVELS ARE LOWER (SEE
TEXT).
Number of Individuals Exposed to Sound Levels ≥160dB
Species
Chukchi Sea
Beaufort Sea
Total
Avg.
Odontocetes
Monodontidae
Beluga
Narwhal
Delphinidae
Killer whale
Phocoenidae
Harbor porpoise
Mysticetes
Bowhead Whale a
Fin whale
Gray whale
Humpback whale
Minke whale
Max.
Avg.
Max.
Avg.
Max.
63
0
254
0
234
0
938
0
298
0
1192
0
2
6
0
0
2
6
57
227
2
6
58
234
9
2
182
2
2
46
6
727
6
6
1531
0
2
0
0
1536
0
6
0
0
1540
2
183
2
2
1582
6
734
6
6
Total Cetaceans
Pinnipeds
Bearded seal
Ribbon seal
Ringed seal
Spotted seal
70
281
1533
1543
1603
1824
270
2
6951
361
405
6
10827
562
322
0
6305
61
1286
0
25221
243
592
2
13256
422
1691
6
36047
804
Total Pinnipeds
5678
8836
6687
26750
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a
See text for description of bowhead whale estimate for the Beaufort Sea
Potential Marine Mammal Disturbance
At Less Than 160 dB Received Levels
During autumn seismic surveys in the
Beaufort Sea, migrating bowhead whales
displayed avoidance (i.e., deflection) at
distances out to 20–30 km (12–19 mi)
and received sound levels of ∼130 dB
(rms) (Miller et al., 1999; Richardson et
al., 1999). Therefore, it is possible that
a larger number of bowhead whales than
estimated above may be disturbed to
some extent if reactions occur at ≥130
dB (rms).
However, these references note that
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 µPa rms,
depending upon propagation.
Corresponding levels at 30 km (18.6 mi)
were about 107–126 dB re 1 µParms.
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
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swimming direction at a distance of 30–
35 km (18.6–21.7 mi), there is no
indication that the sound pressure level
(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, NMFS has noted in the past
that minor course changes during
migration are not considered a
significant behavioral change and, as
indicated in MMS’ 2006 Final 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 when not
migrating but involved in feeding,
bowhead whales do not move away
from a noise source at an SPL of 160 dB.
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Therefore, while bowheads may avoid
an area of 20 km (12.4 mi) around a
noise source, when such a
determination requires a post-survey
computer analysis to find that bowheads
have made slight course change, NMFS
believes that this does not rise to a level
considered to be a significant behavioral
response on the part of the marine
mammals or under the MMPA, 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 µPa).
NMFS needs to point out however, that
while this might not be a ‘‘taking’’ in the
sense that there is not a significant
behavioral response by bowhead
whales, a minor course deflection by
bowheads can have a significant impact
on the subsistence uses of bowheads. As
a result, NMFS still requires mitigation
measures to ensure that the activity does
not have an unmitigable adverse impact
on subsistence uses of bowheads.
Finally, it is likely that SOI will not
conduct seismic operations in the
Beaufort Sea during that part of the fall
bowhead migration that occurs at the
same time as the fall bowhead
subsistence hunt. As a result, a large
proportion of the bowhead population
would migrate past the Beaufort Sea
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seismic survey area without being
exposed to any seismic sounds. Limiting
operations during the fall bowhead
whale migration is also meant to reduce
any chance of conflicting with
subsistence hunting and will continue
at least until hunting quotas have been
filled by the coastal communities.
Potential Impact on Habitat
SOI states that the proposed seismic
activities will not result in any
permanent impact on habitats used by
marine mammals, or to their prey
sources. Seismic activities will mostly
occur during the time of year when
bowhead whales are widely distributed
and would be expected to occur in very
low numbers within the seismic activity
area (mid- to late-July through
September). Any effects would be
temporary and of short duration at any
one place. The primary potential
impacts to marine mammals is
associated with elevated sound levels
from the proposed airguns were
discussed previously in this document.
A broad discussion on the various
types of potential effects of exposure to
seismic on fish and invertebrates can be
found in the NMFS/MMS Draft PEIS for
Arctic Seismic Surveys (see ADDRESSES).
Mortality to fish, fish eggs and larvae
from seismic energy sources would be
expected within a few meters (0.5 to 3
m (1.6 to 9.8 ft)) from the seismic
source. Direct mortality has been
observed in cod and plaice within 48
hours that were subjected to seismic
pulses two meters from the source
(Matishov, 1992), however other studies
did not report any fish kills from
seismic source exposure (La Bella et al.,
1996; IMG, 2002; Hassel et al., 2003). To
date, fish mortalities associated with
normal seismic operations are thought
to be slight. Saetre and Ona (1996)
modeled a worst-case mathematical
approach on the effects of seismic
energy on fish eggs and larvae, and
concluded that mortality rates caused by
exposure to seismic are so low
compared to natural mortality that
issues relating to stock recruitment
should be regarded as insignificant.
Limited studies on physiological
effects on marine fish and invertebrates
to acoustic stress have been conducted.
No significant increases in physiological
stress from seismic energy were
detected for various fish, squid, and
cuttlefish (McCauley et al., 2000) or in
male snow crabs (Christian et al., 2003).
Behavioral changes in fish associated
with seismic exposures are expected to
be minor at best. Because only a small
portion of the available foraging habitat
would be subjected to seismic pulses at
a given time, fish would be expected to
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return to the area of disturbance
anywhere from 15–30 minutes
(McCauley et al., 2000) to several days
(Engas et al., 1996).
Available data indicates that mortality
and behavioral changes do occur within
very close range to the seismic source,
however, the proposed seismic
acquisition activities in the Chukchi and
Beaufort seas are predicted by SOI to
have a negligible effect to the prey
resource of the various life stages of fish
and invertebrates available to marine
mammals occurring during the project’s
duration. In addition, it is unlikely that
bowheads, gray, or beluga whales will
be excluded from any habitat.
Effects of Seismic Noise and Other
Related Activities on Subsistence
The disturbance and potential
displacement of marine mammals by
sounds from seismic activities are the
principal concerns related to
subsistence use within the Beaufort and
Chukchi seas. The harvest of marine
mammals (mainly bowhead whales, but
also ringed and bearded seals) is central
to the culture and subsistence
economies of the coastal North Slope
and Western Alaskan communities. In
particular, if fall-migrating bowhead
whales are displaced farther offshore by
elevated noise levels, the harvest of
these whales could be more difficult
and dangerous for hunters. The impact
would be that whaling crews would
necessarily be forced 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. The harvest
could also be affected if bowheads
become more skittish when exposed to
seismic noise. Hunters relate how
bowhead whales also appear ‘‘angry’’
due to seismic noise, making whaling
more dangerous.
This potential impact on subsistence
uses of marine mammals is proposed by
SOI to be mitigated by application of the
procedures established in a Conflict
Avoidance Agreement (CAA) between
the seismic operators and the AEWC
and the Whaling Captains’ Associations
of Kaktovik, Nuiqsut, Barrow, Pt. Hope
and Wainwright. SOI notes that the
times and locations of seismic and other
noise producing sources are likely to be
curtailed during times of active
bowhead whale scouting and actual
whaling activities within the traditional
subsistence hunting areas of the
potentially affected communities. (See
Mitigation for Subsistence). SOI states
that seismic survey activities will also
be scheduled to avoid the traditional
subsistence beluga hunt which annually
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36053
occurs in July in the community of Pt.
Lay. As a result, SOI believes that there
should be no adverse impacts on the
availability of whale species for
subsistence uses. In the event that a
CAA is not signed by either party, then
NMFS will implement mitigation
measures it determines are necessary to
ensure that the taking of marine
mammals by SOI’s seismic and related
activities do not have an unmitigable
adverse impact on the subsistence uses
of marine mammals.
In the Chukchi Sea, SOI’s seismic
work should not have unmitigable
adverse impacts on the availability of
the whale species for subsistence uses.
The whale species normally taken by
Inupiat hunters are the bowhead and
belugas. SOI’s Chukchi Sea seismic
operations will not begin until after July
20, 2008 by which time the majority of
bowheads will have migrated to their
summer feeding areas in Canada. Even
if any bowheads remain in the
northeastern Chukchi Sea after July 20,
they are not normally hunted after this
date until the return migration occurs
around late September when a fall hunt
by Barrow whalers takes place. 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. Seismic operations for
the Chukchi Sea seismic program will
be timed and located so as to avoid any
possible conflict with the Barrow fall
whaling, and specific provisions
governing the timing and location are
expected to be incorporated, if signed,
into a CAA established between SOI and
WesternGeco, the AEWC, and the
Whaling Captains Associations.
Beluga whales may also be taken
sporadically for subsistence needs by
coastal villages, but traditionally are
taken in small numbers very near the
coast. However, SOI will establish
‘‘communication stations’’ in the
villages to monitor impacts. Gray
whales, which will be abundant in the
northern Chukchi Sea from spring
through autumn, are not taken by
subsistence hunters.
Plan of Cooperation (POC)
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. SOI has
summarized concerns received during
2006 and 2007 into the 2007 POC,
which was submitted during June 2007
to federal agencies as well as to
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subsistence stakeholders, and updated
in July 2007 and earlier this year. SOI
has developed the POC to mitigate and
avoid any unreasonable interference by
SOI’s planned activities on North Slope
subsistence uses and resources. The
POC is the result of numerous meetings
and consultations between SOI, affected
subsistence communities and
stakeholders, and federal agencies
beginning in October 2006 (see Table
12–1 in SOI’s IHA application for a list
of meetings). The POC identifies and
documents potential conflicts and
associated measures that will be taken
to minimize any adverse effects on the
availability of marine mammals for
subsistence use. To be effective, SOI
believes the POC must be a dynamic
document which will expand to
incorporate the communications and
consultation that will continue to occur
throughout 2008. Outcomes of POC
meetings are included in quarterly
updates attached to the POC and
distributed to federal, state, and local
agencies as well as local stakeholder
groups.
SOI hopes that a CAA will result from
the POC meetings. In that regard, the
AEWC submitted a draft CAA to the
industry earlier this spring. If signed,
the CAA will incorporate all appropriate
measures and procedures regarding the
timing and areas of the operator’s
planned activities (e.g., times and places
where seismic operations will be
curtailed or moved in order to avoid
potential conflicts with active
subsistence whaling and sealing); a
communications system between
operator’s vessels and whaling and
hunting crews (i.e., the communications
center will be located in strategic areas);
provision for marine mammal
observers/Inupiat communicators
aboard all project vessels; conflict
resolution procedures; and provisions
for rendering emergency assistance to
subsistence hunting crews. If requested,
post-season meetings will also be held
to assess the effectiveness of a 2008
CAA between SOI, the AEWC, and the
Whaling Captains Associations, to
address how well conflicts (if any) were
resolved; and to receive
recommendations on any changes (if
any) might be needed in the
implementation of future CAAs.
It should be noted that NMFS is
required by the MMPA to make a
determination that an activity would not
have an unmitigable adverse impact on
the subsistence needs for marine
mammals. While this includes usage of
both cetaceans and pinnipeds, the
primary impact from seismic activities
is expected to be impacts from noise on
bowhead whales during its westward
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fall migration and feeding period in the
Beaufort Sea. NMFS has defined
unmitigable adverse impact 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 (50
CFR 216.103).
Therefore, while a signed CAA allows
NMFS to make a determination that the
activity will not have an unmitigable
adverse impact on the subsistence use of
marine mammals, if one or both parties
fail to sign the CAA, then NMFS will
make the determination that the activity
will or will not have an unmitigable
adverse impact on subsistence use of
marine mammals. This determination
may require that the IHA contain
additional mitigation measures in order
for this decision to be made.
Mitigation and Monitoring
As part of its application, SOI has
proposed implementing a marine
mammal mitigation and monitoring
program (4MP) that will consist of
monitoring and mitigation during SOI’s
seismic and shallow-hazard survey
activities. In conjunction with
monitoring during SOI’s exploratory
drilling program (subject to a separate
notice and review), monitoring will
provide information on the numbers of
marine mammals potentially affected by
these activities and permit real time
mitigation to prevent injury of marine
mammals by industrial sounds or
activities. These goals will be
accomplished by conducting vessel-,
aerial-, and acoustic-monitoring
programs to characterize the sounds
produced by the seismic airgun arrays
and related equipment and to document
the potential reactions of marine
mammals in the area to those sounds
and activities. Acoustic modeling will
be used to predict the sound levels
produced by the seismic, shallow
hazards and drilling equipment in the
U.S. Beaufort and Chukchi seas. For the
seismic program, acoustic
measurements will also be made to
establish zones of influence (ZOIs)
around the activities that will be
monitored by observers. Aerial
monitoring and reconnaissance of
marine mammals and recordings of
ambient sound levels, vocalizations of
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marine mammals, and received levels
should they be detectable using bottomfounded acoustic recorders along the
Beaufort Sea coast will be used to
interpret the reactions of marine
mammals exposed to the activities. The
components of SOI’s mitigation and
monitoring programs are briefly
described next. Additional information
can be found in SOI’s application.
Proposed Mitigation Measures
As part of its IHA application, SOI
submitted its proposed mitigation and
monitoring program for SOI’s seismic
programs in the Chukchi and Beaufort
seas for 2008/2009. SOI notes that the
proposed seismic exploration program
incorporates both design features and
operational procedures for minimizing
potential impacts on cetaceans and
pinnipeds and on subsistence hunts.
Seismic survey design features include:
(1) Timing and locating seismic
activities to avoid interference with the
annual fall bowhead whale hunts; (2)
configuring the airgun arrays to
maximize the proportion of energy that
propagates downward and minimizes
horizontal propagation; (3) limiting the
size of the seismic energy source to only
that required to meet the technical
objectives of the seismic survey; and (4)
conducting pre-season modeling and
early season field assessments to
establish and refine (as necessary) the
appropriate 180 dB and 190 dB safety
zones, and other radii relevant to
behavioral disturbance.
The potential disturbance of cetaceans
and pinnipeds during seismic
operations will be minimized further
through the implementation of the
following several ship-based mitigation
measures.
Safety and Disturbance Zones
Safety radii for marine mammals
around airgun arrays are customarily
defined as the distances within which
received pulse levels are greater than or
equal to 180 dB re 1 µPa (rms) for
cetaceans and greater than or equal to
190 dB re 1 µPa (rms) for pinnipeds.
These safety criteria are based on an
assumption that seismic pulses at lower
received levels will not injure these
animals or impair their hearing abilities,
but that higher received levels might
result in such effects. It should be
understood that marine mammals inside
these safety zones will not necessarily
be seriously injured or killed as these
zones were established prior to the
current understanding that significantly
higher levels of impulse sounds would
be required before injury or mortality
would occur. This has been described
previously in this document.
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SOI anticipates that monitoring
similar to that conducted in the Chukchi
Sea in 2007 will also be required in the
Chukchi and the Beaufort seas in 2008.
SOI plans to use marine mammal
observers (MMOs) onboard the seismic
vessel to monitor the 190- and 180–dB
(rms) safety radii for pinnipeds and
cetaceans, respectively and to
implement appropriate mitigation as
discussed in the proceeding sections.
SOI also plans to monitor the 160–dB
(rms) disturbance zone with MMOs
onboard the chase vessels in 2008 as
was done in 2006 and 2007. There has
also been concern that received pulse
levels as low as 120 dB (rms) may have
the potential to disturb some whales. In
2006 and 2007, there was a requirement
in the IHAs issued to SOI by NMFS to
implement special mitigation measures
if specified numbers of bowhead cow/
calf pairs might be exposed to seismic
sounds greater than 120 dB rms or if
large groups (greater than 12
individuals) of bowhead or gray whales
might be exposed to sounds greater than
or equal to 160 dB rms. In 2007,
monitoring of the 120–dB (rms) zone
was required in the Beaufort Sea after 25
September. For 2008, SOI anticipates
that it will not operate in the Chukchi
Sea between September 25th and the
time ice prevents additional work in the
Beaufort Sea, by which time NMFS
believes the bowhead whale cow/calf
migration period to have been
completed. As a result, it is unlikely
that SOI will not need to monitor the
120 dB (rms) zone in the Chukchi Sea
in 2008.
During the 2006 and 2007 seismic
programs in the Chukchi and Beaufort
Seas, SOI utilized a combination of preseason modeling and early season sound
source verification to establish safety
zones for these sound level criteria. As
the equipment being utilized in 2008 is
the same as that used in the 2006 and
2007 field seasons, and the majority of
locations where seismic data is to be
acquired were modeled prior to the
2006 and 2007 seasons, SOI will
initially utilize the derived (measured)
sound criterion distances from 2006.
Any locations not modeled previously
will be modeled prior to 2008 survey
initiation and mitigation distances and
safety zones adjusted up, if necessary
following sound measurements at the
new locations. Modeling of the sound
propagation is based on the size and
configuration of the airgun array and on
available oceanographic data. An
acoustics contractor will perform the
direct measurements of the received
levels of underwater sound versus
distance and direction from the airgun
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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
mitigation measures to be implemented
will include ramp ups, power downs,
and shut downs as described next.
Ramp-Up
A ramp up of an airgun array provides
a gradual increase in sound levels, and
involves a step-wise 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 the time for them to
leave the area and thus avoid any
potential injury or impairment of their
hearing abilities. During the proposed
seismic program, the seismic operator
will ramp up the airgun arrays slowly,
at a rate no greater than 6 dB/5 minute
period. Full ramp ups (i.e., from a cold
start after a shut down, when no airguns
have been firing) will begin by firing a
small airgun in the arrays. The
minimum duration of a shut-down
period, i.e., without air guns firing,
which must be followed by a ramp up
typically is the amount of time it would
take the source vessel to cover the 180–
dB safety radius. That depends on ship
speed and the size of the 180–dB safety
radius, which are not known at this
time.
A full ramp up, after a shut down,
will not begin until there has been a
minimum of a 30-minute period of
observation by MMOs of the safety zone
to assure that no marine mammals are
present. The entire safety zone must be
visible during the 30-minute leading up
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 periods of turn around and
transit between seismic transects, at
least one airgun will remain operational
to alert marine mammals in the area of
the vessel’s location. The ramp-up
procedure still will be followed when
increasing the source levels from one air
gun to the full arrays. Moreover, keeping
one air gun firing will avoid the
prohibition of a cold start during
darkness or other periods of poor
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36055
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 hr/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.
Power Downs and Shut Downs
A power down is the immediate
reduction in the number of operating
airguns from all guns firing to some
smaller number. A shut down is the
immediate cessation of firing of all
airguns. The airgun arrays will be
immediately powered down whenever a
marine mammal is sighted approaching
close to or within the applicable safety
zone of the full airgun arrays (i.e., 180
dB rms for cetaceans, 190 dB rms for
pinnipeds), but is outside the applicable
safety zone of the single airgun. If a
marine mammal is sighted within the
applicable safety zone of the single
airgun, the airgun array will be shut
down (i.e., no airguns firing). Although
observers will be located on the bridge
ahead of the center of the airgun array,
the shutdown criterion for animals
ahead of the vessel will be based on the
distance from the bridge (vantage point
for MMOs) rather than from the airgun
array - a precautionary approach. For
marine mammals sighted alongside or
behind the airgun array, the distance is
measured from the array.
Operations at Night and in Poor
Visibility
When operating under conditions of
reduced visibility attributable to
darkness or to adverse weather
conditions, infra-red or night-vision
binoculars will be available for use.
However, it is recognized that their
effectiveness is limited. For that reason,
MMOs will not routinely be on watch at
night, except in periods before and
during ramp-ups. It should be noted that
if one small airgun remains firing, the
rest of the array can be ramped up
during darkness or in periods of low
visibility. Seismic operations may
continue under conditions of darkness
or reduced visibility.
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Preliminary Mitigation Determination
As NMFS believes that the
combination of use of the mitigation
gun, ramp-up of the seismic airgun array
and the slow vessel speed (to allow
marine mammals sufficient time to take
necessary avoidance measures), the use
of trained marine mammal observers
and shut-down procedures (to avoid
potential injury if the animal is close to
the vessel), and the behavioral response
of marine mammals (especially
bowhead whales) to avoid areas of high
anthropogenic noise all provide
protection to marine mammals from
serious injury or mortality. As a result,
NMFS believes that it is not necessary
to require termination of survey
activities during darkness or reduced
visibility and that the current level of
mitigation will result in the lowest level
of impact on marine mammals
practicable.
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Proposed Marine Mammal Monitoring
SOI has proposed to implement a
marine mammal monitoring program
(4MP) to collect data to address the
following specific objectives: (1)
improve the understanding of the
distribution and abundance of marine
mammals in the Chukchi and Beaufort
sea project areas; (2) understand the
propagation and attenuation of
anthropogenic sounds in the waters of
the project areas; (3) determine the
ambient sound levels in the waters of
the project areas; and (4) assess the
effects of sound on marine mammals
inhabiting the project areas and their
distribution relative to the local people
that depend on them for subsistence
hunting.
These objectives and the monitoring
and mitigation goals will be addressed
by: (1) vessel-based MMOs on the
seismic source and other support
vessels; (2) an acoustic program to
predict and then measure the sounds
produced by the seismic operations and
the possible responses of marine
mammals to those sounds; (3) an aerial
monitoring and reconnaissance of
marine mammals available for
subsistence harvest along the Chukchi
Sea coast; and (4) bottom-founded
autonomous acoustic recorder arrays
along the Alaskan coast and offshore in
the Chukchi and Beaufort seas to record
ambient sound levels, vocalizations of
marine mammals, and received levels of
seismic operations should they be
detectable.
Seismic Source Vessel-based Visual
Monitoring
A sufficient number of MMOs will be
required to be onboard the seismic
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source vessel to meet the following
criteria: (1) 100 percent monitoring
coverage during all periods of seismic
operations in daylight and for the 30
minutes prior to starting ramp-up and
for the number of minutes required to
reach full ramp-up; (2) coverage during
darkness for 30-minutes before and
during ramp-ups (provided MMOs
verify that they can clearly see the entire
safety zone); (3) maximum of 4
consecutive hours on watch per MMO;
(4) maximum of approximately 12 hours
on watch per day per MMO with no
other shipboard duties; and (5) twoMMO coverage during ramp-up and the
30 minutes prior to full ramp-ups and
for as large a fraction of the other
operating hours as possible.
To accomplish these tasks SOI
proposes to have from three to five
MMOs (including one Inupiat observer/
communicator) based aboard the
seismic vessel. However, NMFS does
not consider Inupiat observers to be
included in the required minimum
number of MMOs unless they have
undergone MMO training at a facility
approved in advance by NMFS. MMOs
will search for and observe marine
mammals whenever seismic operations
are in progress and for at least 30
minutes before the planned start of
seismic transmissions or whenever the
seismic array’s operations have been
suspended for more than 10 minutes.
The MMOs will scan the area
immediately around the vessels with
reticle binoculars during the daytime.
Laser rangefinding equipment will be
available to assist with distance
estimation. After mid-August, when the
duration of darkness increases, image
intensifiers will be used by observers
and additional light sources may be
used to illuminate the safety zone.
The seismic vessel-based work will
provide the basis for real-time
mitigation (airgun power downs and, as
necessary, shut downs), as called for by
the IHAs; information needed to
estimate the ‘‘take’’ of marine mammals
by harassment, which must be reported
to NMFS; data on the occurrence,
distribution, and activities of marine
mammals in the areas where the seismic
program is conducted; information to
compare the distances, distributions,
behavior; movements of marine
mammals relative to the source vessels
at times with and without seismic
activity; a communication channel to
Inupiat whalers through the
Communications Coordination Center in
coastal villages; and continued
employment and capacity building for
local residents, with one objective being
to develop a larger pool of experienced
Inupiat MMOs.
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The use of four or more MMOs allows
two observers to be on duty
simultaneously for up to 50 percent of
the active airgun hours. The use of two
observers increases the probability of
detecting marine mammals, and two
observers will be on duty for the entire
duration of time whenever the seismic
array is ramped up. As mentioned
previously, individual watches will be
limited to no more than 4 consecutive
hours to avoid observer fatigue (and no
more than 12 hours on watch per 24
hour day). When mammals are detected
within or about to enter the safety zone
designated to prevent injury to the
animals (see Mitigation), the
geophysical crew leader will be notified
so that shutdown procedures can be
implemented immediately. Details of
the vessel-based marine mammal
monitoring program are described in
SOI’s IHA application (see Appendix B).
Chase Boat Monitoring
MMOs will also be present on smaller
support vessels that travel with the
seismic source vessel. These support
vessels are commonly known as ‘‘guard
boats’’ or ‘‘chase boats.’’ During seismic
operations, a chase boat remains very
near to the stern of the source vessel
anytime that a member of the source
vessel crew is on the back deck
deploying or retrieving equipment
related to the seismic array. Once the
seismic array is deployed the chase boat
then serves to keep other vessels away
from the seismic source vessel and the
seismic array itself (including
hydrophone streamer) during
production of seismic data and provide
additional emergency response
capabilities.
In the Chukchi and Beaufort seas in
2008, SOI’s seismic source vessel will
have one associated chase boat and
possibly an additional supply vessel.
The chase boat and supply vessel (if
present) will have three MMOs onboard
to collect marine mammal observations
and to monitor the 160 dB (rms)
disturbance zone from the seismic
airgun array. MMOs on the chase boats
will be able to contact the seismic ship
if marine mammals are sited. To
maximize the amount of time during the
day that an observer is on duty, two
observers aboard the chase boat or
supply vessel will rarely work at the
same time. As on the source vessels,
shifts will be limited to 4 hrs in length
and 12 hrs total in a 24 hr period.
SOI plans to monitor the 160–dB
(rms) disturbance radius in 2008 using
MMOs onboard the chase vessel. The
160–dB radius in the Chukchi Sea in
2007 was determined by JASCO (2007)
to extend ∼8.1 km from the airgun
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source on the M/V Gilavar. In the
Beaufort Sea, the 160–dB radius was
measured at 13.45 km (8.4 mi) (JASCO,
2007). This area around the seismic
vessel was monitored by MMOs
onboard the M/V Gulf Provider (the
chase boat used in 2006 and 2007
operations). As in 2007 during
monitoring of the 160–dB zone the
M/V Gulf Provider will travel ∼8 km (5
mi) ahead and to the side of the M/V
Gilavar. MMOs onboard the M/V Gulf
Provider will search the area ahead of
the M/V Gilavar within the 160–dB zone
for marine mammals. Every 8 km (5 mi)
or so, the M/V Gulf Provider will move
to the other side of the M/V Gilivar
continuing in a stair-step type pattern.
The distance at which the M/V Gulf
Provider (or other equivalent vessel)
travels ahead of the M/V Gilavar will be
determined by the measured 160–dB
radius. Mitigation (i.e., power down or
shut down of the airgun array) will be
implemented if a group of 12 or more
bowhead or gray whales enter the 160–
dB zone. SOI will use this same protocol
in the Beaufort Sea after the 160–dB
radius has been determined. Depending
upon the size of the measured 160–dB
zone around the airgun array SOI may
decide to use a vessel equipped with a
Passive Acoustic Monitoring (PAM)
system (if it has been independently
field tested and certified to NMFS as
being capable of detecting marine
mammals that inhabit the Arctic Ocean)
or may use a second chase boat to
ensure effective monitoring of the area.
In 2007 the measured distance to the
180–dB isopleth ranged from about 2.45
km (1.5 mi) in the Chukchi Sea to about
2.2 km (1.4 mi) in the Beaufort Sea near
the Sivulliq prospect. SOI decided to
use an additional vessel to monitor this
zone given its importance in protecting
marine mammals from potential injury
associated with exposure to seismic
pulses. Depending upon the measured
radius for the 180–dB zone in 2008/
2009 SOI may elect to use a PAM
system to help monitor this area around
the M/V Gilavar as well.
Aerial Survey Program
SOI proposes to conduct an aerial
survey program in support of the
seismic exploration program in the
Beaufort Sea during summer and fall of
2008. The objectives of the aerial survey
will be: (1) to advise operating vessels
as to the presence of marine mammals
in the general area of operation; (2) to
provide mitigation monitoring (120 dB
zones) as may be required under the
conditions of the IHA; (3) to collect and
report data on the distribution,
numbers, movement and behavior of
marine mammals near the seismic
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operations with special emphasis on
migrating bowhead whales; (4) to
support regulatory reporting and Inupiat
communications related to the
estimation of impacts of seismic
operations on marine mammals; (5) to
monitor the accessibility of bowhead
whales to Inupiat hunters and (6) to
document how far west of seismic
activities bowhead whales travel before
they return to their normal migration
paths, and if possible, to document how
far east of seismic operations the
deflection begins.
The same aerial survey design will be
implemented during the summer
(August) and fall (late August-October)
period, but during the summer, the
survey grid will be flown twice a week,
and during the fall, flights will be
conducted daily. During the early
summer, few cetaceans are expected to
be encountered in the nearshore
Alaskan Beaufort Sea where seismic
surveys will be conducted. Those
cetaceans that are encountered are
expected to be either along the coast
(gray whales: (Maher, 1960; Rugh and
Fraker, 1981; Miller et al., 1999; Treacy,
2000) or seaward of the continental
shelf among the pack ice (bowheads:
Moore et al., 1989b; Miller et al., 2002;
and belugas: Moore et al., 1993; Clark et
al., 1993; Miller et al., 1999) north of the
area where seismic surveys and drilling
activities are to be conducted. During
some years a few gray whales are found
feeding in shallow nearshore waters
from Barrow to Kaktovik but most
sightings are in the western part of that
area.
During the late summer and fall, the
bowhead whale is the primary species
of concern, but belugas and gray whales
are also present. Bowheads and belugas
migrate through the Alaskan Beaufort
Sea from summering areas in the central
and eastern Beaufort Sea and Amundsen
Gulf to their wintering areas in the
Bering Sea (Clarke et al., 1993; Moore et
al., 1993; Miller et al., 2002). Some
bowheads are sighted in the eastern
Alaskan Beaufort Sea starting midAugust and near Barrow starting late
August but the main migration does not
start until early September.
The aerial survey procedures will be
generally consistent with those during
earlier industry studies (Miller et al.,
1997, 1998, 1999; Patterson et al., 2007).
This will facilitate comparison and
pooling of data where appropriate.
However, SOI notes that the specific
survey grids will be tailored to SOI’s
operations and the time of year.
Information on survey procedures can
be found in SOI’s IHA application.
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36057
Survey Design in the Beaufort Sea in
Summer
The main species of concern in the
Beaufort Sea is the bowhead whale but
small numbers of belugas, and in some
years, gray whales, are present in the
Beaufort Sea during summer (see
above). Few bowhead whales are
expected to be found in the Beaufort Sea
during early August; however, a
reduced aerial survey program is
proposed during the summer prior to
seismic operations to confirm the
distribution and numbers of bowheads,
gray whales and belugas, because no
recent surveys have been conducted at
this time of year. The few bowheads that
were present in the Beaufort Sea during
summer in the late 1980s were generally
found among the pack ice in deep
offshore waters of the central Beaufort
Sea (Moore and DeMaster, 1998; Moore
et al., 2000). Although gray whales were
rarely sighted in the Beaufort Sea prior
to the 1980’s (Rugh and Fraker, 1981),
sightings appear to have become more
common along the coast of the Beaufort
Sea in summer and early fall (Miller et
al., 1999; Treacy 1998, 2000, 2002;
Patterson et al., 2007) possibly because
of increases in the gray whale
population and/or reductions in ice
cover in recent years. Because no
summer surveys have been conducted
in the Beaufort Sea since the 1980s, the
information on summer distribution of
cetaceans will be valuable for planning
future seismic or drilling operations.
The grid that will be flown in the
summer will be the same grid flown
later in the year, but it will be flown
twice a week instead of daily. If
ceteceans are encountered in the
vicinity of planned seismic operations,
then SOI would consider flying the
survey grid proposed for later in the
season, rather than the early-season
survey plan. Surveys will be conducted
2 days/week until the period one week
prior to the start of seismic operations
in the Beaufort Sea. Beginning
approximately one week prior to the
start of seismic operations, daily surveys
would be initiated and they would be
conducted using the grid shown in
Figure 3 in Appendix B of SOI’s IHA
application.
Survey Design in the Beaufort Sea in
Fall
Aerial surveys during the late AugustOctober period will be designed to
provide mitigation monitoring as
required by the IHA. SOI notes that, if,
as in 2006 and 2007, mitigation
monitoring is required to ensure that
large aggregations of mother-calf
bowheads do not approach to within the
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120 dB re 1 µPa (rms) radius from the
active seismic operation, priority will be
given to mitigation monitoring to the
east of the seismic operation (see
Appendix B, Figure 2). SOI suggests,
that, if permitted by the IHA, it is
prepared to conduct some surveys to
collect data on the extent of westward
deflection while still monitoring the
120–dB radius to the east of the seismic
operation. These surveys will obtain
detailed data (weather permitting) on
the occurrence, distribution, and
movements of marine mammals,
particularly bowhead whales, within an
area that extends about 100 km (62 mi)
to the east of the primary seismic vessel
to a few km west of it, and north to
about 65 km (40 mi) offshore. A
westward emphasis would obtain the
same data for an area about 100 km (62
mi) to the west of the primary seismic
vessel and about 20 km (12 mi) east of
it; again about 65 km (40 mi) offshore.
This site-specific survey coverage will
complement the simultaneous MMS/
NMFS National Marine Mammal
Laboratory Bowhead Whales Aerial
Survey Program (BWASP) survey
coverage of the broader Beaufort Sea
area.
The proposed survey grid will
provide data both within and beyond
the anticipated immediate zone of
influence of the seismic program, as
identified by Miller et al. (1999). Miller
et al. (1999) were not able to determine
how far upstream and downstream (i.e.,
east and west) of the seismic operations
bowheads began deflecting and then
returned to their ‘‘normal’’ migration
corridor. That is an important concern
for the Inupiat whalers. SOI notes that
the proposed survey grid is not able to
address that concern because of the
need to extend flights well to the east to
detect mother-calf pairs before they are
exposed to seismic sounds greater than
120 dB re 1 µPa.
It is possible that the east-west extent
of seismic surveys will change during
the season due to ice or other
operational restrictions. If so, SOI may
need to modify the aerial survey grid to
maintain observations to 100 km (62 mi)
east (or west) of the seismic survey area,
but the total km/mi of survey that can
be conducted each day are limited by
the fuel capacity of the aircraft. The
only alternative to ensure adequate
aerial survey coverage over the entire
area where seismic activities might
influence bowhead whale distribution is
to space the individual transects farther
apart. For each 15–20 km (9.3–12.4 mi)
increase in the east-west size of the
seismic survey area, the spacing
between lines will need to be increased
by 1 km (0.62 mi) to maintain survey
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coverage from 100 km (62 mi) east to 20
km (12.4 mi) west of the seismic
activities (or vice versa). Data from the
easternmost transects of the proposed
survey grid will document the main
bowhead whale migration corridor east
of the seismic exploration area and will
provide the baseline data on the
location of the migration corridor
relative to the coast.
SOI does not propose to fly a smaller
‘‘intensive’’ survey grid in 2008/2009. In
previous years, a separate grid of 4–6
shorter transects was flown, whenever
possible, to provide additional survey
coverage within about 20 km (12.4 mi)
of the seismic operations. This coverage
was designed to provide additional data
on marine mammal utilization of the
actual area of seismic exploration and
immediately adjacent waters. The 1996–
98 studies showed that bowhead whales
were almost entirely absent from the
area within 20 km (12.4 mi) of the active
seismic operation (Miller et al. 1997,
1998, 1999). Thus, the flying-time that
(in the past) would have been expended
on flying the intensive grid will be used
to extend the coverage farther to the east
and west of the seismic activity.
Depending on the distance offshore
where seismic is being conducted, the
survey grid may not extend far enough
offshore to document whales which
could potentially deflect north of the
operation. In this case, SOI plans to
extend the north ends of the transects
farther north so that they extend 30–35
km (19–22 mi) north of the seismic
operation and the two most westerly (or
easterly depending upon the survey
design) lines will not be surveyed. This
will mean that the survey lines will only
extend as far west as the seismic
operation or start as far east as the
seismic operations. SOI states that it is
not possible to move the grid north
without surveying areas south of the
seismic operation because some whales
may deflect south of the seismic
operation and that deflection must be
monitored.
If seismic surveys of the Beaufort Sea
end while substantial numbers of
bowhead whales are still migrating
west, aerial survey coverage of the area
of most recent seismic operations will
continue for several days after seismic
surveys have ended. This will provide
‘‘post-seismic’’ data on whale
distribution for comparison with whale
distribution during seismic periods.
These data will be used in analyses to
estimate the extent of deflection during
seismic activities and the duration of
any potential deflection after surveys
end. Post seismic coverage will not be
conducted if the bowhead migration has
ended by that time, but it is expected
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that due to freeze-up, seismic operations
will move out of the Beaufort Sea before
the end of the bowhead whale
migration.
The survey grid patterns for summer
and fall time periods being proposed by
SOI are described in SOI’s IHA
application.
Joint Industry Studies Program
Chukchi Sea Coastal Aerial Survey
The only recent aerial surveys of
marine mammals in the Chukchi Sea
were conducted along coastal areas of
the Chukchi Sea to approximately 20
nmi (37 km) offshore in 2006 and 2007
in support of SOI’s summer seismic
exploration. These surveys provided
data on the distribution and abundance
of marine mammals in nearshore waters
of the Chukchi Sea. Population sizes of
several species found they may have
changed considerably since earlier
surveys were conducted and their
distributions may have changed because
of changes in ice conditions. SOI plans
to conduct an aerial survey program in
the Chukchi Sea in 2008 that will be
similar to the 2006 and 2007 programs.
Alaskan Natives from several villages
along the east coast of the Chukchi Sea
hunt marine mammals during the
summer and Native communities are
concerned that offshore oil and gas
development activities such as seismic
exploration may negatively impact their
ability to harvest marine mammals. Of
particular concern is the potential
impact on the beluga harvest at Point
Lay and on future bowhead harvests at
Point Hope, Wainwright and Barrow.
Other species of concern in the Chukchi
Sea include the gray whale, bearded,
ringed, and spotted seals, and walrus.
The gray whale is expected to be the
most numerous cetacean species
encountered during the proposed
summer seismic activities, although
beluga whales also occur in the area.
The ringed seal is likely to be the most
abundant pinniped species. The current
aerial survey program has been designed
to collect distribution data on cetaceans
but will be limited in its ability to
collect similar data on pinnipeds
because of aircraft altitude.
The aerial survey program will be
conducted in support of the SOI seismic
program in the Chukchi Sea during
summer and fall of 2008/2009. The
objectives of the aerial survey will be (1)
to address data deficiencies in the
distribution and abundance of marine
mammals in coastal areas of the eastern
Chukchi Sea; and (2) to collect and
report data on the distribution,
numbers, orientation and behavior of
marine mammals, particularly beluga
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whales, near traditional hunting areas in
the eastern Chukchi Sea.
With agreement from hunters in the
coastal villages, aerial surveys of coastal
areas to approximately 20 mi (37 km)
offshore between Point Hope and Point
Barrow will begin in early- to mid-July
and will continue until mid-November
or until seismic operations in the
Chukchi Sea are completed. Weather
and equipment permitting, surveys will
be conducted twice per week during
this time period. In addition, during the
2008/2009 field season, SOI will
coordinate and cooperate with the aerial
surveys conducted by NMML for MMS
and any other groups conducting
surveys in the same region. For a
description of the aerial survey
procedures, please see SOI’s IHA
application.
Acoustic ‘‘Net’’ Array: Chukchi Sea
The acoustic ‘‘net’’ array used during
the 2007 field season in the Chukchi Sea
was designed to accomplish two main
objectives. The first was to collect
information on the occurrence and
distribution of beluga whales that may
be available to subsistence hunters near
villages located on the Chukchi Sea
coast. The second objective was to
measure the ambient noise levels near
these villages and record received levels
of sounds from seismic survey activities
further offshore in the Chukchi Sea.
The net array configuration used in
2007 is again proposed for 2008/2009.
The basic components are 30 ocean
bottom hydrophones (OBH) systems.
Two separate deployments with
different placement configurations are
planned. The first deployment will
occur in mid-July immediately
following the beluga hunt and will be
adjusted to avoid any interference with
the hunt. The initial net array
configuration will include and extend
the 2006 configuration (see Figures 8
and 9 in Appendix B of SOI’s
application for number of OBHs and
locations for the two deployments).
These offshore systems will capture
seismic exploration sounds over large
distances to help characterize the sound
transmission properties of larger areas of
the Chukchi Sea.
The second deployment will occur in
late August at the same time that all
currently deployed systems will be
recovered for battery replacement and
data extraction. The second deployment
emphasizes the offshore coverage out to
72 degrees North (80 nm north of
Wainwright, 150 nm (172 mi; 278 km)
north of Point Lay, and 180 nm (207mi;
333 km) north of Cape Lizbourne. The
primary goal of extending the arrays
further offshore later in the season is to
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obtain greater coverage of the central
Chukchi Sea to detect vocalization from
migrating bowheads starting in
September. The specific geometries and
placements of the arrays are primarily
driven by the objectives of (a) detecting
the occurrence and approximate
offshore distributions of belugas and
possibly bowhead whales during the
July to mid-August period and primarily
by bowhead whales during the midAugust to late-October period, (b)
measuring ambient noise, and (c)
measuring received levels of seismic
survey activities. Timing of deployment
and final positions will b subject to
weather and ice conditions, based on
consultation with local villages, and
carried out to minimize any interference
with subsistence hunting or fishing
activities.
Additionally, a set of 4 to 6 OBH
systems will be deployed near the end
of the season to collect data throughout
the winter.
Acoustic Array: Beaufort Sea
In addition to the continuation of the
acoustic net array program in the
Chukchi Sea in 2008/2009, SOI
proposes to also continue a program that
deployed directional acoustic recording
systems in the Beaufort Sea. The
purpose of the array will be to further
understand, define, and document
sound characteristics and propagation
resulting from offshore seismic and
other industry operations that may have
the potential to cause deflections of
bowhead whales from anticipated
migratory pathways. Of particular
interest will be the east-west extent of
deflection (i.e. how far east of a sound
source do bowheads begin to deflect and
how far to the west beyond the sound
source does deflection persist). Of
additional interest will be the extent of
offshore deflection that occurs.
In previous work around seismic and
drill-ship operations in the Alaskan
Beaufort Sea, the primary method for
studying this question has been aerial
surveys. Acoustic localization methods
provide a supplementary methods for
addressing these questions. As
compared with aerial surveys, acoustic
methods have the advantage of
providing a vastly larger number of
whale detections, and can operate day
or night, independent of visibility, and
to some degree independent of ice
conditions and sea state-all of which
prevent or impair aerial surveys.
However, acoustic methods depend on
the animals to call, and to some extent
assume that calling rate is unaffected by
exposure to industrial noise. Bowheads
do call frequently in the fall, but there
is some evidence that their calling rate
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36059
may be reduced upon exposure to
industrial sounds, complicating
interpretation. The combined use of
acoustic and aerial survey methods will
provide information about these issues.
SOI has contracted with Greeneridge
to conduct the whale acoustic
monitoring program using the passive
acoustics techniques developed and
used successfully since 2001 for
monitoring the bowhead migration past
BP’s Northstar oil production facility
northwest of Prudhoe Bay. Those
techniques involve using directional
autonomous seafloor acoustic recorders
(DASARs) to measure the arrival angles
of bowhead calls at known locations,
then triangulating to locate the calling
whale. Thousands, in some years tens of
thousands, of whale calls have been
located each year since 2001. The 2008/
2009 study will use a new model of the
DASAR similar to those deployed in
2007. Figure 11 in Appendix B of SOI’s
IHA application shows potential
locations of the DASARs. The results of
these data will be used to determine the
extent of deflection of migrating
bowhead whales from the sound
sources. More information on DASARs
and this part of SOI’s monitoring
program can be found in SOI’s IHA
application.
Additional Mitigation and Monitoring
Measures
In addition to the standard mitigation
and monitoring measures mentioned
previously, NMFS is proposing to
incorporate additional mitigation/
monitoring measures (such as expanded
monitoring-safety zones for bowhead
and gray whales, and having those
zones monitored effectively) into the
2008/2009 IHA to ensure that impacts
on marine mammals are at the lowest
level practicable. The additional
mitigation measures are specific for the
SOI seismic project, in part because SOI
incorporated monitoring measures in
the 4MP document that makes this
monitoring practicable. It should be
recognized that these mitigation/
monitoring measures do not establish
NMFS policy applicable to other
projects or other locations under NMFS’
jurisdiction, as each application for an
IHA is context-specific. These measures
have been developed based upon
available data specific to the project
areas. NMFS and MMS intend to collect
additional information from all sources,
including industry, non-governmental
organizations, Alaska Natives and other
federal and state agencies regarding
measures necessary for effectively
monitoring marine mammal
populations, assessing impacts from
seismic on marine mammals, and
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Chukchi/Beaufort Seas in 2008 under
the previous IHA.
Reporting
Daily Reporting
In its IHA application, SOI proposes
to collect, via the aerial flights,
unanalyzed bowhead sighting and
flightline data which will be exchanged
between MMS and SOI on a daily basis
during the field season. NMFS is
proposing that each team will also
submit its sighting information to NMFS
in Anchorage each day. After the SOI
and MMS data files have been reviewed
and finalized, they will be shared in
digital form.
mstockstill on PROD1PC66 with NOTICES
Interim Report
The results of the 2008 SOI vesselbased monitoring, including estimates
of take by harassment, will be presented
in the ‘‘90 day’’ and final Technical
Report as required by NMFS under
IHAs. SOI proposes that the Technical
Report will include: (1) summaries of
monitoring effort: total hours, total
distances, and distribution through
study period, sea state, and other factors
affecting visibility and detectability of
marine mammals; (2) analyses of the
effects of various factors influencing
detectability of marine mammals: sea
state, number of observers, and fog/
glare; (3) species composition,
occurrence, and distribution of marine
mammal sightings including date, water
depth, numbers, age/size/gender
categories, group sizes, and ice cover;
(4) sighting rates of marine mammals
versus operational state (and other
variables that could affect detectability);
(5) initial sighting distances versus
operational state; (6) closest point of
approach versus seismic state; (7)
observed behaviors and types of
movements versus operational state; (8)
numbers of sightings/individuals seen
versus operational state; (9) distribution
around the drilling vessel and support
vessels versus operational state; and (10)
estimates of take based on (a) numbers
of marine mammals directly seen within
the relevant zones of influence (160 dB,
180 dB, 190 dB (if SPLs of that level are
measured)), and (b) numbers of marine
mammals estimated to be there based on
sighting density during daytime hours
with acceptable sightability conditions.
This report will be due 90 days after
termination of the 2008 open water
season and will include the results from
any seismic work conducted in the
VerDate Aug<31>2005
21:19 Jun 24, 2008
Jkt 214001
provide a basis for integration of the
data sets over a period of years.
Comprehensive Monitoring Reports
determining practicable measures for
mitigating those impacts. MMS and
NMFS anticipate that mitigation
measures applicable to future seismic
and other activities may change and
evolve based on newly-acquired data.
Endangered Species Act (ESA)
Under section 7 of the ESA, the NMFS
has begun consultation with MMS on
the proposed seismic survey activities
in the Beaufort and Chukchi seas during
2008/2009. NMFS will also consult on
the issuance of the IHA under section
101(a)(5)(D) of the MMPA to SOI for this
activity. Consultation will be concluded
prior to NMFS making a determination
on the issuance of an IHA.
In November, 2007, SOI (in
coordination and cooperation with other
Arctic seismic IHA holders) released a
final, peer-reviewed edition of the 2006
Joint Monitoring Program in the
Chukchi and Beaufort Seas, JulyNovember 2006 (LGL, 2007). This report
is available for downloading on the
NMFS website (see ADDRESSES). A draft
comprehensive report for 2007 was
provided to NMFS and those attending
the NMFS/MMS Arctic Ocean open
water meeting in Anchorage, AK on
April 14–16, 2008. Based on reviewer
comments made at that meeting, SOI is
currently revising this report and plans
to make it available to the public
shortly.
Following the 2008 open water
season, a comprehensive report
describing the proposed acoustic,
vessel-based, and aerial monitoring
programs will be prepared. The 2008
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 their impacts on
marine mammals in the Beaufort Sea
during 2008 (work conducted in 2009
under the proposed 2008/2009 IHA will
be analyzed in a 2009 comprehensive
report). The 2008 report will form the
basis for future monitoring efforts and
will establish long term data sets to help
evaluate changes in the Beaufort/
Chukchi Sea ecosystems. The report
will also incorporate studies being
conducted in the Chukchi Sea and 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.
This comprehensive report will
consider data from many different
sources including two relatively
different types of aerial surveys; several
types of acoustic systems for data
collection (net array, passive acoustic
monitoring, vertical array, and other
acoustical monitoring systems that
might be deployed), and vessel based
observations. Collection of comparable
data across the wide array of programs
will help with the synthesis of
information. However, interpretation of
broad patterns in data from a single year
is inherently limited. Much of the 2008
data will be used to assess the efficacy
of the various data collection methods
and to establish protocols that will
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National Environmental Policy Act
(NEPA)
In 2006, the MMS prepared Draft and
Final Programmatic Environmental
Assessments (PEAs) for seismic surveys
in the Beaufort and Chukchi Seas.
Availability of the Draft and Final PEA
was noticed by NMFS in several Federal
Register notices regarding issuance of
IHAs to SOI and others. NMFS was a
cooperating agency in the preparation of
the MMS PEA. On November 17, 2006,
NMFS and MMS announced that they
were jointly preparing a Draft
Programmatic Environmental Impact
Statement (PEIS) to assess the impacts
of MMS’ annual authorizations under
the Outer Continental Shelf (OCS)
Lands Act to the U.S. oil and gas
industry to conduct offshore
geophysical seismic surveys in the
Chukchi and Beaufort seas off Alaska,
and NMFS’ authorizations under the
MMPA to incidentally harass marine
mammals while conducting those
surveys. On March 30, 2007, the
Environmental Protection Agency (EPA)
noticed the availability for comment of
the NMFS/MMS Draft PEIS. A Final
PEIS has not been completed. In order
to meet NMFS’ NEPA requirements for
the proposed IHA to SOI, NMFS is
preparing a supplement to the 2006
Final PEA which incorporates by
reference the 2006 Final PEA and other
related documents. Upon completion, a
copy of this Supplemental EA will be
available upon request.
Preliminary Determinations
Based on the information provided in
SOI’s application, this document, the
MMS 2006 Final PEA for Arctic Seismic
Surveys, the 2006 and 2007
Comprehensive Monitoring Reports by
SOI and others, and NMFS’ 2008 Final
Supplemental EA, NMFS has
preliminarily determined that the
impact of SOI conducting seismic
surveys in the northern Chukchi Sea
and eastern and central Beaufort Sea in
2008/2009 will have no more than a
negligible impact on marine mammals
and that there will not be any
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unmitigable adverse impacts to
subsistence communities, provided the
mitigation measures described in this
document are implemented (see
Mitigation).
For reasons explained previously in
this document, NMFS has preliminarily
determined that no take by serious
injury, death or stranding is anticipated
by, or authorized to, SOI’s 2008/2009
seismic survey activities, and the
potential for temporary or permanent
hearing impairment is low and will be
avoided through the incorporation of
the mitigation measures mentioned in
this document. 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. NMFS
has preliminarily determined that
exposure to several seismic pulses at
received levels near 200-205 dB (rms)
might result in slight TTS in hearing in
a small odontocete. Seismic pulses with
received levels of 200-205 dB or more
are usually restricted to a radius of no
more than 200 m (656 ft) around a
seismic vessel operating a large array of
airguns. For baleen whales, while there
are no data, direct or indirect, on levels
or properties of sound that are required
to induce TTS, there is a strong
likelihood that baleen whales
(bowheads, gray whales and humpback
whales) would avoid the approaching
airguns (or vessel) before being exposed
to levels high enough for there to be any
possibility of onset of TTS. For
pinnipeds, information indicates that
for single seismic impulses, sounds
would need to be higher than 190 dB
rms for TTS to occur while exposure to
several seismic pulses indicates that
some pinnipeds may incur TTS at
somewhat lower received levels than do
small odontocetes exposed for similar
durations. Therefore, the requirement
for MMOs to monitor safety zones (180
dB for cetaceans, 190 dB for pinnipeds)
and power-down or shutdown arrays
even at this distance and the increasing
effectiveness of an MMO seeing a
marine mammal prior to entering a
close-in zone where auditory injury
could occur indicates to NMFS that the
180 dB and 190-dB safety zones for
cetaceans and pinnipeds respectively,
provides a sufficient buffer to prevent
PTS in marine mammals.
NMFS has also preliminarily
determined that only small numbers of
marine mammals will be harassed by
SOI’s 2008 seismic and shallow hazard
programs. As discussed previously, the
species most likely to be harassed
during seismic surveys in the Arctic
Ocean area is the ringed seal, with a
total ‘‘best estimate’’ of 13,256 animals
VerDate Aug<31>2005
21:19 Jun 24, 2008
Jkt 214001
being ‘‘exposed’’ to sound levels of 160
dB or greater(6,951 animals in the
Chukchi Sea and 6,305 animals in the
Beaufort Sea)(see Table 1). As explained
previously, this does not mean that this
is the number of ringed seals that will
actually have a behavioral reaction to
the noise, rather it is simply the best
estimate of the number of animals that
potentially could have a behavioral
modification due to the noise. For
example Moulton and Lawson (2002)
indicate that most pinnipeds exposed to
seismic sounds lower than 170 dB do
not visibly react to that sound;
pinnipeds are not likely to react to
seismic sounds unless they are greater
than 170 dB re 1 microPa (rms). In
addition as discussed previously, these
estimates are calculated based upon line
miles of survey effort (also animal
density and the calculated zone of
influence), the resulting take estimate
numbers tend to be highly inflated,
because animals that might have been
affected (taken) are likely to have moved
out of the area to avoid additional
annoyance from the seismic sounds
(assuming they were taken in the first
place). As a result, NMFS believes that
these ‘‘exposure’’ estimates for
pinnipeds are conservative and seismic
and shallow hazard surveys will
actually affect significantly less than 5
percent of the Beaufort and Chukchi Sea
ringed seal populations. This
preliminary finding also applies to other
pinniped species in the Arctic.
Even if the estimate of 13,256 ringed
seals being behaviorally harassed is not
a small number in absolute terms, it is
relatively small, representing only about
5.3 percent of the regional stock size of
that species (249,000), if each
‘‘exposure’’ at 160 dB represents an
individual ringed seal that has reacted
to that sound and less if a higher SPL
is required for a behavioral reaction (as
is expected) or animals moved out of the
seismic area. As a result, we believe that
these ‘‘exposure’’ estimates are
conservative and seismic and shallow
hazard surveys will actually affect
significantly less than 5 percent of the
Beaufort and Chukchi Sea ringed seal
populations. This finding also applies to
other pinniped species in the Arctic.
The estimated number of Level B
harassment takes represented as
‘‘exposures’’ during SOI’s seismic and
shallow hazard surveys in the Beaufort
and Chukchi seas is 297 beluga (63 in
the Chukchi Sea, 234 in the Beaufort
Sea) and 1,540 bowheads (9 in the
Chukchi Sea and 1,531 in the Beaufort
Sea). The Level B harassment ‘‘take’’
estimate represents less than 1 percent
of the combined Beaufort and Chukchi
Seas beluga stock size of 42,968 (39,258
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Fmt 4703
Sfmt 4703
36061
in the Beaufort Sea; 3,710 in the
Chukchi Sea), a relatively small number.
For bowhead whales, this Level B
harassment ‘‘take’’ estimate represents
between 12 percent (based on 13,326
bowheads which assumes a 3.4 percent
annual population growth rate from the
2001 estimate) and 14 percent of the
Bering-Chukchi-Beaufort Seas bowhead
population (based on the 2001
population estimate of 10,545 animals).
However, NMFS currently estimates
that this population percentage estimate
will be lower because SOI has
significantly reduced its planned days
of seismic surveys in the Beaufort Sea
to only 20 days (September 25 to about
October 15th or when surveys are
curtailed by ice).
While these exposure numbers may
represent a somewhat sizable portion of
the population size of bowhead whales
(12-14 percent), NMFS believes that the
estimated number of bowhead
exposures overestimate actual takings
for the following reasons: (1) SOI plans
to concentrate its 3D seismic survey
program in 2008 in the Lease Sale 193
area of the Chukchi Sea and only move
into the Beaufort Sea after the bowhead
subsistence hunt is completed (and a
sizeable portion of the bowhead
population will have migrated past
SOI’s planned seismic location by that
time), and (2) the proposed shallow
hazard survey activities would occur in
the Chukchi and Beaufort seas at a time
when bowheads are mostly
concentrated in the Canadian Beaufort
Sea. As a result, NMFS has
preliminarily determined that relatively
few bowhead whales will be taken and
that only small numbers of marine
mammals will be harassed by SOI’s
2008 seismic and shallow hazard
programs.
Therefore, NMFS has preliminarily
determined that the short-term impact
of conducting seismic surveys in the
U.S. Chukchi and Beaufort seas may
result, at worst, in a temporary
modification in behavior by certain
species of marine mammals. While
behavioral and avoidance reactions may
be made by these species in response to
the resultant noise, this behavioral
change is expected to have a negligible
impact on the animals. While the
number of potential incidental
harassment takes will depend on the
distribution and abundance of marine
mammals (which vary annually due to
variable ice conditions and other
factors) in the area of seismic
operations, the number of potential
harassment takings is estimated to be
small (see Estimated Takes for NMFS’
analysis). In addition, for reasons
described previously, injury (temporary
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36062
Federal Register / Vol. 73, No. 123 / Wednesday, June 25, 2008 / Notices
or permanent hearing impairment) and/
or mortality is unlikely and will be
avoided through the incorporation of
the mitigation measures mentioned in
this document and required by the
authorization. No rookeries, mating
grounds, areas of concentrated feeding,
or other areas of special significance for
marine mammals occur within or near
the planned area of operations during
the season of operations.
Finally, NMFS has preliminarily
determined that the proposed seismic
activity by SOI in the northern Chukchi
Sea and central and eastern Beaufort Sea
in 2008/2009 will not have an
unmitigable adverse impact on the
subsistence uses of bowhead whales and
other marine mammals. This
preliminary determination is supported
by the information in this Federal
Register Notice, including: (1) Seismic
activities in the Chukchi Sea will not
begin until after July 20 by which time
the spring bowhead hunt is expected to
have ended; (2) that the fall bowhead
whale hunt in the Beaufort Sea will
either be governed by a CAA between
SOI and the AEWC and village whaling
captains or by mitigation measures to
protect subsistence hunting of marine
mammals contained in the IHA; (3) the
CAA or IHA conditions will
significantly reduce impacts on
subsistence hunters to ensure that there
will not be an unmitigable adverse
impact on subsistence uses of marine
mammals; (4) while it is possible that
accessibility to belugas during the
spring subsistence beluga hunt could be
impaired by the survey, it is unlikely
because very little of the proposed
survey is within 25 km (15.5 mi) of the
Chukchi Sea coast, meaning the vessel
will usually be well offshore and away
from areas where seismic surveys would
influence beluga hunting by
communities; and (5) because seals
(ringed, spotted, bearded) are hunted in
nearshore waters and the seismic survey
will remain offshore of the coastal and
nearshore areas of these seals where
natives would harvest these seals, it
should not conflict with harvest
activities.
As a result of these preliminary
determinations, NMFS proposes to issue
an IHA to SOI for conducting a seismic
survey in the northern Chukchi Sea and
central and eastern Beaufort Sea in
2008/2009, provided the previously
mentioned mitigation, monitoring, and
reporting requirements are incorporated.
VerDate Aug<31>2005
21:23 Jun 24, 2008
Jkt 214001
Dated: June 20, 2008.
P. Michael Payne,
Acting Director, Office of Protected Resources,
National Marine Fisheries Service.
[FR Doc. E8–14393 Filed 6–24–08; 8:45 am]
BILLING CODE 3510–22–S
Background
COMMITTEE FOR THE
IMPLEMENTATION OF TEXTILE
AGREEMENTS
Request for Public Comment on
Commercial Availability Request under
the North American Free Trade
Agreement (NAFTA)
June 19, 2008.
The Committee for the
Implementation of Textile Agreements
(CITA).
ACTION: Request for Public Comments
concerning a request for modification of
the NAFTA rules of origin for thread
and yarn of acrylic staple fiber.
AGENCY:
SUMMARY: On June 10, 2008, the
Government of the United States
received a request from the Government
of Canada alleging that acrylic staple
fiber, classified in subheading 5503.30
of the Harmonized Tariff Schedule of
the United States (HTSUS), cannot be
supplied by the domestic industry in
commercial quantities in a timely
manner and requesting that the
governments of Mexico and the United
States consult to consider whether the
North American Free Trade Agreement
(NAFTA) rule of origin for thread and
yarns classified under HTSUS
subheadings 55.08 through 55.11 should
be modified to allow the use of nonNorth American acrylic staple fiber.
The President may proclaim a
modification to the NAFTA rules of
origin only after reaching an agreement
with the other NAFTA countries on the
modification. CITA hereby solicits
public comments on this request, in
particular with regard to whether acrylic
staple fiber of HTSUS subheading
5503.30 can be supplied by the
domestic industry in commercial
quantities in a timely manner.
Comments must be submitted by July
25, 2008 to the Chairman, Committee for
the Implementation of Textile
Agreements, Room 3001, United States
Department of Commerce, Washington,
D.C. 20230.
FOR FURTHER INFORMATION CONTACT:
Martin J. Walsh or Maria K. Dybczak,
International Trade Specialists, Office of
Textiles and Apparel, U.S. Department
of Commerce, (202) 482-2818 and (202)
482-3651, respectively.
SUPPLEMENTARYINFORMATION:
PO 00000
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Fmt 4703
Authority: Section 204 of the Agricultural
Act of 1956, as amended (7 USC 1854);
Section 202(q) of the North American Free
Trade Agreement Implementation Act (19
USC 3332(q)); Executive Order 11651 of
March 3, 1972, as amended.
Sfmt 4703
Under the NAFTA, NAFTA countries
are required to eliminate customs duties
on textile and apparel goods that qualify
as originating goods under the NAFTA
rules of origin, which are set out in
Annex 401 to the NAFTA. The NAFTA
provides that the rules of origin for
textile and apparel products may be
amended through a subsequent
agreement by the NAFTA countries. See
Section 202(q) of the NAFTA
Implementation Act. In consultations
regarding such a change, the NAFTA
countries are to consider issues of
availability of supply of fibers, yarns, or
fabrics in the free trade area and
whether domestic producers are capable
of supplying commercial quantities of
the good in a timely manner. The
NAFTA Implementation Act provides
the President with the authority to
proclaim modifications to the NAFTA
rules of origin as are necessary to
implement an agreement with one or
more NAFTA country on such a
modification. See section 202(q) of the
NAFTA Implementation Act.
On June 10, 2008, the Government of
the United States received a request
from the Government of Canada alleging
that acrylic staple fiber, classified in
subheading 5503.30 of the HTSUS,
cannot be supplied by the domestic
industry in commercial quantities in a
timely manner and requesting that the
governments of Mexico and the United
States consult to consider whether the
NAFTA rule of origin for thread and
yarns classified under HTSUS
subheadings 55.08 through 55.11 should
be modified to allow the use of nonNorth American acrylic staple fiber.
CITA is soliciting public comments
regarding this request, particularly with
respect to whether acrylic staple fiber
can be supplied by the domestic
industry in commercial quantities in a
timely manner. Comments must be
received no later than July 25, 2008.
Interested persons are invited to submit
six copies of such comments or
information to the Chairman, Committee
for the Implementation of Textile
Agreements, room 3100, U.S.
Department of Commerce, 14th and
Constitution Avenue, N.W.,
Washington, DC 20230.
If a comment alleges that acrylic
staple fiber can be supplied by the
domestic industry in commercial
quantities in a timely manner, CITA will
E:\FR\FM\25JNN1.SGM
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Agencies
[Federal Register Volume 73, Number 123 (Wednesday, June 25, 2008)]
[Notices]
[Pages 36044-36062]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E8-14393]
[[Page 36044]]
-----------------------------------------------------------------------
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XD76
Taking Marine Mammals Incidental to Specified Activities; Seismic
Surveys in the Beaufort and Chukchi Seas
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice of receipt of application and proposed incidental take
authorization; request for comments.
-----------------------------------------------------------------------
SUMMARY: NMFS has received an application from Shell Offshore, Inc.
(SOI) and its contractor WesternGeco for an Incidental Harassment
Authorization (IHA) to take small numbers of marine mammals, by
harassment, incidental to conducting marine geophysical programs,
including deep seismic surveys, on oil and gas lease blocks located on
Outer Continental Shelf (OCS) waters in the Beaufort and Chukchi Seas.
Under the Marine Mammal Protection Act (MMPA), NMFS is requesting
comments on its proposal to issue an IHA to SOI and WesternGeco to
incidentally take, by Level B harassment, small numbers of several
species of marine mammals during the Arctic Ocean open-water seasons
between August 1, 2008 and July 31, 2009, incidental to conducting
these seismic surveys.
DATES: Comments and information must be received no later than July 25,
2008.
ADDRESSES: Written comments on the application should be addressed to
Mr. P. Michael Payne, Chief, Permits, Conservation and Education
Division, Office of Protected Resources, National Marine Fisheries
Service, 1315 East-West Highway, Silver Spring, MD 20910-3225, or by
telephoning the contact listed here. The mailbox address for providing
email comments is PR1.XD76@noaa.gov. Comments sent via e-mail,
including all attachments, must not exceed a 10-megabyte file size.
A copy of the application (containing a list of the references used
in this document) may be obtained by writing to this address or by
telephoning the contact listed here and are also available at: https://
www.nmfs.noaa.gov/pr/permits/incidental.htm#iha.
A copy of the Minerals Management Service (MMS) Final Programmatic
Environmental Assessment (Final PEA) and the NMFS/MMS Draft
Programmatic Environmental Impact Statement (Draft PEIS) are available
at: https://www.mms.gov/alaska/.
Documents cited in this document that are not available through
standard public library access methods, may be viewed, by appointment,
during regular business hours at this address.
FOR FURTHER INFORMATION CONTACT: Kenneth Hollingshead, Office of
Protected Resources, NMFS, (301) 713-2289, or Brad Smith, NMFS, Alaska
Regional Office 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 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.
An authorization shall be granted if NMFS finds that the taking
will have a negligible impact on the species or stock(s) and will not
have an unmitigable adverse impact on the availability of the species
or stock(s) for subsistence uses and the permissible methods of taking
and requirements pertaining to the mitigation, monitoring and reporting
of such takings are set forth. NMFS has defined ``negligible impact''
in 50 CFR 216.103 as ''...an impact resulting from the specified
activity that cannot be reasonably expected to, and is not reasonably
likely to, adversely affect the species or stock through effects on
annual rates of recruitment or survival.''
Section 101(a)(5)(D) of the MMPA established an expedited process
by which citizens of the United States can apply for an authorization
to incidentally take small numbers of marine mammals by harassment.
Except with respect to certain activities not pertinent here, the MMPA
defines ``harassment'' as:
any act of pursuit, torment, or annoyance which (i) has the
potential to injure a marine mammal or marine mammal stock in the
wild [Level A harassment]; or (ii) has the potential to disturb a
marine mammal or marine mammal stock in the wild by causing
disruption of behavioral patterns, including, but not limited to,
migration, breathing, nursing, breeding, feeding, or sheltering
[Level B harassment].
Section 101(a)(5)(D) establishes a 45-day time limit for NMFS
review of an application followed by a 30-day public notice and comment
period on any proposed authorizations for the incidental harassment of
marine mammals. Within 45 days of the close of the comment period, NMFS
must either issue or deny the authorization.
Summary of Request
On October 16, 2007, NMFS received an application from SOI for the
taking, by harassment, of several species of marine mammals incidental
to conducting a marine seismic survey program during the open water
season between August 1, 2008 and July 31, 2009 (referred to in this
document as 2008/2009). SOI is planning a variety of programs in the
Chukchi and Beaufort Seas during the 2008/2009 open water seasons,
including a: (1) Chukchi Sea deep 3-D seismic survey; (2) Beaufort Sea
deep 3-D seismic survey; and (3) Beaufort Sea marine surveys, which
includes three activities: (a) site clearance and shallow hazards
surveys; (b) an ice-gouge survey; and (c) a strudel scour survey.
The deep seismic survey components of the program will be conducted
from WesternGeco's vessel, M/V Gilavar. Detailed specifications on this
seismic survey vessel are provided in Attachment A of SOI's IHA
application. These specifications include: (1) complete descriptions of
the number and lengths of the streamers which form the hydrophone
arrays; (2) airgun size and sound propagation properties; and (3)
additional detailed data on the M/V Gilavar's characteristics. In
summary, the M/V Gilavar will tow two source arrays, comprising three
identical subarrays each, which will be fired alternately as the ship
progresses downline in the survey area. The M/V Gilavar will tow up to
6 streamer cables up to 5.4 kilometers (km)(3.4 mi) long. With this
configuration each pass of the M/V Gilavar can record 12 subsurface
lines spanning a swath of up to 360 meters (1181 ft). The seismic
acquisition vessel will be supported by the M/V Gulf Provider, or a
similar vessel. The M/V Gulf Provider will serve as a crew change,
resupply, fueling support of acoustic and marine mammal monitoring, and
seismic chase vessel. It will not deploy seismic acquisition gear.
As SOI's 2007 IHA for open water seismic activities in the Chukchi
and Beaufort Seas is valid until August 1, 2008, this IHA request is
intended, therefore, for the open water seasons between August 2, 2008
through July 31, 2009.
As marine mammals may be affected by seismic and vessel noise, SOI
has requested an authorization under section 101(a)(5)(D) of the MMPA
to
[[Page 36045]]
take marine mammals by Level B harassment while conducting seismic
surveys and related activities.
Plan for Seismic Operations
In its application, SOI notes that it plans for the M/V Gilavar to
be in the Chukchi Sea to begin seismic acquisition data on or after
July 20, 2008, move to the Beaufort Sea in mid-July through late
October, and conclude work in the Chukchi Sea around November 15, 2008.
For purposes of the MMPA, the Chukchi and Beaufort seas meet the
definition of a ``specific geographic region'' as defined under the
Act. As proposed, the 2008 seismic survey effort will last a maximum of
100 days of active data acquisition (excluding downtime due to weather
and other unforeseen delays). When ice conditions permit or when SOI
determines to do so (at present, SOI plans to work in the Chukchi Sea
until around September 25), the seismic and associated vessels will
transit to the Beaufort Sea to conduct seismic operation for part of
the this 100-day period. The proposed commencement date of July 20th
for starting seismic in the Chukchi Sea is designed to ensure that
there will be no conflict with the spring bowhead whale migration and
subsistence hunts conducted by Barrow, Pt. Hope, or Wainwright or the
beluga subsistence hunt conducted by the village of Pt. Lay in early
July. The approximate area of SOI's seismic survey operations are shown
in Figure 1 in SOI's IHA application.
3-D Deep Seismic Surveys
Chukchi Sea 3-D Deep Seismic Surveys
SOI and its geophysical (seismic) contractor, WesternGeco, propose
to conduct a marine geophysical (deep 3-D seismic) survey program
during open water season on various MMS Outer Continental Shelf (OCS)
lease blocks in the northern Chukchi Sea (see Figure 1 in SOI's IHA
application). The Chukchi Sea 3-D Deep Seismic survey will be conducted
on leases obtained under Lease Sale (LS) 193. The exact locations where
operations will occur within that sale area were not known at the time
of SOI's IHA application, but NMFS presumes they will take place on
lease blocks obtained as a result of the sale. However, in general SOI
notes that the seismic data acquisition will occur at least 25 mi (40
km) offshore of the coast and in waters with depths averaging about 40
m (131 ft).
The deep 3-D seismic survey is proposed to be conducted from
WesternGeco's vessel M/V Gilavar, described previously. Two ``chase
boats'' will accompany the seismic vessel. These two chase boats will
provide the following functions: (1) re-supply, (2) marine mammal
monitoring, (3) ice scouting, and (4) general support for the M/V
Gilavar. The chase boat vessels proposed for use in 2008 are the M/V
Theresa Marie and the M/V Torsvik. These vessels will not deploy any
seismic gear. In addition, a crew change vessel, the M/V Gulf Provider
or similar vessel and a landing craft, such as the M/V Maxime or
similar vessel, will support the M/V Gilavar, and the two chase boats
in the Chukchi Sea. The crew change vessel will be used to move
personnel and supplies from the seismic vessel, and two chase boats to
the nearshore areas. In turn, the landing craft will move personnel and
supplies from the crew change vessel, when it is located in nearshore
areas, to the beach (most likely this will be at Barrow). Lastly, the
Marine Mammal Monitoring and Mitigation Program (4MP) will have a
separate vessel for the proposed 2008 Program. The landing craft also
will be used to move personnel and equipment from the 4MP vessel to the
near shore areas.
Beaufort Sea Deep 3-D Seismic Surveys
The same seismic vessel (M/V Gilavar), seismic equipment, and chase
boats that are described for the Chukchi Sea Deep 3-D Seismic survey,
will be used to conduct deep 3-D seismic surveys in the central and
eastern Beaufort Sea (see Figure 2 in SOI's IHA application). The focus
of this activity will be on SOI's existing leases, but some activity in
the Beaufort Sea may occur outside of SOI's existing leases. The
landing craft, which will be used to move personnel and supplies from
vessels in the near shore to docking sites will most likely use West
Dock, or Oliktok Dock. Smaller vessels such as the Alaska Clean Seas
(ACS) bay boats, or similar vessels, may be used to assist in the
movement of people and supplies and support of the 4MP in the Beaufort
Sea. The specific geographic region for SOI's deep seismic program in
the Beaufort Sea will be in OCS waters including SOI leases beginning
east of the Colville River delta to west of the village of Kaktovik
(see Figure 2 in SOI's application). According to SOI's IHA
application, the Beaufort Sea program is planned to occur for a maximum
of 60 days (excluding downtime due to weather and unforeseen delays)
during open-water from mid-August to the end of October; however,
recent communications with SOI indicates that the Beaufort Sea seismic
program will not start until after September 25, 2008. This timing of
activities in the fall will avoid any significant conflict with the
Beaufort Sea bowhead whale subsistence hunt conducted by the Beaufort
Sea villages, because it is anticipated that the fall bowhead whale
hunt will have ended by that time.
Description of Marine 3-D Seismic Data Acquisition
In the seismic method, reflected sound energy produces graphic
images of seafloor and sub-seafloor features. The seismic system
consists of sources and detectors, the positions of which must be
accurately measured at all times. The sound signal comes from arrays of
towed energy sources. These energy sources store compressed air which
is released on command from the towing vessel. The released air forms a
bubble which expands and contracts in a predictable fashion, emitting
sound waves as it does so. Individual sources are configured into
arrays. These arrays have an output signal, which is more desirable
than that of a single bubble, and also serve to focus the sound output
primarily in the downward direction, which is useful for the seismic
method. This array effect also minimizes the sound emitted in the
horizontal direction.
The downward propagating sound travels to the seafloor and into the
geologic strata below the seafloor. Changes in the acoustic properties
between the various rock layers result in a portion of the sound being
reflected back toward the surface at each layer. This reflected energy
is received by detectors called hydrophones, which are housed within
submerged streamer cables which are towed behind the seismic vessel.
Data from these hydrophones are recorded to produce seismic records or
profiles. Seismic profiles often resemble geologic cross- sections
along the course traveled by the survey vessel.
Description of WesternGeco's Air-Gun Array
SOI is proposing to use WesternGeco's 3147-in\3\ Bolt-Gun Array for
its 3-D seismic survey operations in the Chukchi and Beaufort Seas.
WesternGeco's source arrays are composed of 3 identically tuned Bolt-
gun sub-arrays operating at an air pressure of 2,000 psi. In general,
the signature produced by an array composed of multiple sub-arrays has
the same shape as that produced by a single sub-array while the overall
acoustic output of the array is determined by the number of sub-arrays
employed.
The airgun arrangement for each of the three 1049-in\3\ sub-array
is detailed in SOI's application. As indicated in the
[[Page 36046]]
application's diagram, each sub-array is composed of six tuning
elements; two 2-airgun clusters and four single airguns. The standard
configuration of a source array for 3-D surveys consists of one or more
1049-in\3\ sub-arrays. When more than one sub-array is used, as here,
the strings are lined up parallel to each other with either 8 m or 10 m
(26 or 33 ft) cross-line separation between them. This separation was
chosen so as to minimize the areal dimensions of the array in order to
approximate point source radiation characteristics for frequencies in
the nominal seismic processing band. For the 3147-in\3\ array the
overall dimensions of the array are 15 m (49 ft) long by 16-m (52.5-ft)
wide.
Characteristics of Airgun Pulses
A discussion of the characteristics of airgun pulses was provided
in several previous Federal Register documents (see 69 FR 31792 (June
7, 2004) or 69 FR 34996 (June 23, 2004)) and is not repeated here.
Additional information can be found in the NMFS/MMS Draft PEIS (see
ADDRESSES). Reviewers are encouraged to read these earlier documents
for additional background information.
Marine Surveys
SOI proposes to conduct marine surveys (shallow hazards and other
activities) in the Beaufort and Chukchi seas in 2008. Acoustic systems
similar to the ones proposed for use by SOI during its planned marine
surveys have been described by NMFS previously (see 66 FR 40996 (August
6, 2001), 70 FR 13466 (March 21, 2005)). NMFS encourages readers to
refer to these documents for additional information on these systems. A
summary of SOI's planned activities is described next.
Beaufort Sea Marine Surveys
SOI proposes to conduct three marine survey activities in 2008 in
the U.S. Beaufort Sea: (1) Site Clearance and Shallow Hazards (2) Ice
Gouge Surveys, and (3) Strudel Scour Surveys. Marine surveys for site
clearance and shallow hazards, ice gouge, or strudel scour in the
Beaufort Sea can be accomplished by the M/V Henry Christofferson. No
other vessels, such as chase boats, are necessary to accomplish the
proposed marine survey work. Any necessary crew changes or 4MP
coordinated activities under this activity will utilize the same crew
change, landing craft, or 4MP vessel mentioned under the Beaufort Sea
Deep 3-D Seismic survey.
Site Clearance and Shallow Hazards
Marine surveys will include site clearance and shallow hazards
surveys of potential exploratory drilling locations. These surveys
gather data on: (1) bathymetry, (2) seabed topography and other seabed
characteristics (e.g., boulder patches), (3) potential geohazards
(e.g., shallow faults and shallow gas zones), and (4) the presence of
any archeological features (e.g., shipwrecks).
The focus of this activity will be on SOI's existing leases in the
central and eastern Beaufort Sea, but some activity may occur outside
of SOI's existing leases. Actual locations of site clearance and
shallow hazard surveys have not been definitively set as of the date of
this publication, although they will occur within the area outlined in
Figure 2 of SOI's IHA application.
The vessel that SOI expects to use for the site clearance and
shallow hazards surveys is the M/V Henry Christofferson, which is a
diesel-powered tug as described in Attachment A to SOI's IHA
application. SOI proposes to use the following acoustic
instrumentation, (or similar equipment) during this work. This is the
same equipment as was used on the M/V Henry Christofferson during 2007:
(1) Dual frequency subbottom profiler Datasonics CAP6000 Chirp II
(2 to7 kiloHertz [kHz] or 8 to 23 kHz) or similar;
(2) Medium penetration subbottom profiler, Datasonics SPR-1200
Bubble Pulser (400 (hertz [Hz]) or similar;
(3) High resolution multi-channel 2D system, 20 cubic inches
(in\3\) (2 by 10) gun array (0 to 150 Hz) or similar;
(4) Multi-beam bathymetric sonar, Seabat 8101 (240 Hz); or similar;
and
(5) Side-scan sonar system, Datasonics SIS-1500 (190 to 210 kHz) or
similar.
Ice Gouge Survey
Ice gouge surveys are a type of marine survey to determine the
depth and distribution of ice gouges in the sea bed. Ice gouge is
created by ice keels which project from the bottom of moving ice that
gouge into seafloor sediment. Remnant ice gouge features are mapped to
aid in predicting the prospect of, orientation, depth, and frequency of
future ice gouge. These surveys will focus on the potential,
prospective pipeline corridor between the Sivulliq Prospect in Camden
Bay and the nearshore Point Thomson area. The Sivulliq area will be
surveyed to gather geotechnical and seafloor hazard information as well
as data on ice gouges.
SOI proposes that the acoustic instrumentation described previously
in this document (or something similar) will be used, namely multi-beam
bathymetric sonar, side scan sonar and subbottom profiling. Actual
locations of the ice gouge surveys have not been definitively set as of
the date of this publication, although these will occur within the area
outlined in Figure 2 of SOI's IHA application. There are also some
platform siting lines proposed, which would employ a high resolution
multi-channel 2D system, 20 cubic inches (in\3\) (2 by 10) airgun array
(0 to 150 Hz) or similar system.
Strudel Scour Survey
During the early melt on the North Slope, the rivers begin to flow
and discharge water over the coastal sea ice near the river deltas.
That water rushes down holes in the ice (``strudels'') and scours the
seafloor. These erosional areas are called ``strudel scours''.
Information on these features is required for prospective pipeline
planning. Two proposed activities are required to gather this
information.
First, an aerial survey will be conducted via helicopter
overflights during the melt to locate the strudels; and strudel scour
marine surveys to gather bathymetric data. The overflights investigate
possible sources of overflood water and will survey local streams that
discharge in the vicinity of Point Thomson including the Staines River,
which discharges to the east into Flaxman Lagoon and the Canning River,
which discharges to the east directly into the Beaufort Sea. These
helicopter overflights were scheduled to occur during late May/early
June 2008 and, weather permitting, should take no more than four days.
There are no planned landings during these overflights other than at
the Deadhorse or Kaktovik airports.
Second, areas that have strudel scour identified during the aerial
survey will be verified and surveyed with a marine vessel after the
breakup of nearshore ice. This proposed activity is not anticipated to
take more than 5 days to conduct. The operation is conducted in the
shallow water areas near the coast in the vicinity of Point Thomson.
The vessel has not been contracted; however, it is anticipated that it
will be the diesel-powered R/V Annika Marie. This vessel will use the
following equipment:
(1) Multi-beam bathymetric sonar, Seabat 8101 (240 Hz); or similar
sonar; and
(2) Side-scan sonar system, Datasonics SIS-1500 (190 to 210 kHz) or
similar sonar.
The multi-beam bathymetric sonar and the side-scan sonar systems
both operate at frequencies greater than 180
[[Page 36047]]
kHz, the highest frequency considered by knowledgeable marine mammal
biologists to be of possible influence to marine mammals. Because no
taking of marine mammals will occur from this equipment, no
measurements of those two sources are planned by SOI, and no exclusion
zones for seals or whales would be established during operation of
those two sources. The acoustic instrumentation used on the seismic
vessels are described in SOI's IHA application.
Chukchi Sea Marine Surveys
Marine surveys will include site clearance and shallow hazards
surveys of potential exploratory drilling locations as required by MMS
regulations. These surveys gather data on: (1) bathymetry, (2) seabed
topography and other seabed characteristics (e.g., boulder patches),
(3) potential geohazards (e.g., shallow faults and shallow gas zones),
and (4) the presence of any archeological features (e.g., shipwrecks).
Marine surveys for site clearance and shallow hazards can be
accomplished by one vessel with acoustic sources. No other vessels,
such as chase boats, are necessary to accomplish the proposed work. Any
necessary crew changes or 4MP coordinated activities under this
activity will utilize the same crew change, landing craft, or 4MP
vessel mentioned under the Chukchi Sea deep 3D seismic surveys.
The Chukchi Sea marine surveys will be conducted by SOI on leases
acquired in OCS LS 193. Site clearance surveys are confined to small
specific areas within OCS blocks. Actual locations of site clearance
and shallow hazard surveys have not been definitively set as of the
date of SOI's IHA application, although these will occur within the
general area outlined in Figure 1 in SOI's IHA application. Before the
commencement of operations, survey location information will be
supplied to NMFS, MMS, other agencies and affected members of the
public as it becomes available. SOI has not contracted for a vessel at
the time of publication of this document.
Additional Information
A detailed description of the work proposed by SOI for the open-
water seasons of 2008/2009 is contained in SOI's application which is
available for review (see ADDRESSES). Also, a description of SOI's data
acquisition program proposed for the 2008/2009 season, and
WesternGeco's air-gun array to be employed during 2008/2009 has been
provided in previous IHA notices on SOI's seismic program (see 71 FR
26055, May 3, 2006; 71 FR 50027, August 24, 2006).
Description of Habitat and Marine Mammals Affected by the Activity
A detailed description of the Beaufort and Chukchi sea ecosystems
and their associated marine mammal populations can be found in the
NMFS/MMS Draft PEIS and the MMS Final Programmatic Environmental
Assessment (Final PEA) on Seismic Surveys (see ADDRESSES for
availability) and also in several other documents (e.g., MMS, 2007
Final EIS for Chukchi Sea Planning Area: Oil and Gas Lease Sale 193 and
Seismic Surveying Activities in the Chukchi Sea. MMS 2007-026).
Marine Mammals
The Beaufort/Chukchi Seas support a diverse assemblage of marine
mammals, including bowhead whales, gray whales, beluga whales, killer
whales, harbor porpoise, ringed seals, spotted seals, bearded seals,
walrus and polar bears. These latter two species are under the
jurisdiction of the U.S. Fish and Wildlife Service (USFWS) and are not
discussed further in this document. Descriptions of the biology and
distribution of the marine mammal species under NMFS' jurisdiction can
be found in SOI's IHA application, the 2007 NMFS/MMS Draft PEIS on
Arctic Seismic Surveys, and the MMS 2006 Final PEA on Arctic Seismic
Surveys. Information on these marine mammal species can also be found
in NMFS Stock Assessment Reports (SARS). The 2007 Alaska SARS document
is available at: https://www.nmfs.noaa.gov/pr/pdfs/sars/ak2007.pdf.
Please refer to those documents for information on these species.
Potential Effects of Seismic Surveys on Marine Mammals
Disturbance by seismic noise is the principal means of taking by
this activity. Support vessels and aircraft may provide a potential
secondary source of noise. The physical presence of vessels and
aircraft could also lead to non-acoustic effects on marine mammals
involving visual or other cues.
As outlined in previous NMFS documents, the effects of noise on
marine mammals are highly variable, and can, in general, be categorized
as follows (based on Richardson et al., 1995):
(1) The noise may be too weak to be heard at the location of the
animal (i.e., lower than the prevailing ambient noise level, the
hearing threshold of the animal at relevant frequencies, or both);
(2) The noise may be audible but not strong enough to elicit any
overt behavioral response;
(3) The noise may elicit reactions of variable conspicuousness and
variable relevance to the well being of the marine mammal; these can
range from temporary alert responses to active avoidance reactions such
as vacating an area at least until the noise event ceases;
(4) Upon repeated exposure, a marine mammal may exhibit diminishing
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;
(5) Any anthropogenic noise that is strong enough to be heard has
the potential to reduce (mask) the ability of a marine mammal to hear
natural sounds at similar frequencies, including calls from
conspecifics, and underwater environmental sounds such as surf noise;
(6) If mammals remain in an area because it is important for
feeding, breeding or some other biologically important purpose even
though there is chronic exposure to noise, it is possible that there
could be noise-induced physiological stress; this might in turn have
negative effects on the well-being or reproduction of the animals
involved; and
(7) Very strong sounds have the potential to cause temporary or
permanent reduction in hearing sensitivity. In terrestrial mammals, and
presumably marine mammals, received sound levels must far exceed the
animal's hearing threshold for there to be any temporary threshold
shift (TTS) in its hearing ability. For transient sounds, the sound
level necessary to cause TTS is inversely related to the duration of
the sound. Received sound levels must be even higher for there to be
risk of permanent hearing impairment. In addition, intense acoustic or
explosive events may cause trauma to tissues associated with organs
vital for hearing, sound production, respiration and other functions.
This trauma may include minor to severe hemorrhage.
Effects of Seismic Survey Sounds on Marine Mammals
Behavioral Effects
In its IHA application, SOI states that the only anticipated
impacts to marine mammals associated with noise propagation from vessel
movement and seismic airgun operations would be the
[[Page 36048]]
temporary and short term displacement of whales and seals from within
ensonified zones produced by such noise sources. Any impacts on the
whale and seal populations of the Beaufort and Chukchi Seas activity
areas are likely to be short-term and transitory arising from the
temporary displacement of individuals or small groups from locations
they may occupy at the times they are exposed to seismic sounds between
the 160- to 190-dB received levels. In the case of bowhead whales
however, that displacement might well take the form of a deflection of
the swim paths of migrating bowheads away from (seaward of) received
noise levels lower than 160 db (Richardson et al., 1999). Moreover, it
is not presently known at what distance after passing the seismic
source that bowheads will return to their previous migration route.
However, NMFS does not believe that this offshore deflection is
biologically significant (although it might be significant for purposes
of subsistence hunting, as discussed later) as the bowhead migration is
believed to remain within the general bowhead whale migratory corridor
in the U.S. Beaufort Sea, which varies annually based on environmental
factors.
SOI cites Richardson and Thomson [eds]. (2002) to support its
contention that there is no conclusive evidence that exposure to sounds
exceeding 160 dB have displaced bowheads from feeding activity. NMFS
notes that, in 2006, observations conducted onboard a seismic vessel
operating in the Canadian Beaufort Sea found that feeding bowhead
whales were not observed to respond to seismic sounds at levels of 160
dB or lower.
Results from the 1996-1998 BP and Western Geophysical seismic
monitoring programs in the Beaufort Sea indicate that most fall
migrating bowheads deflected seaward to avoid an area within about 20
km (12.4 mi) of an active nearshore seismic operation, with the
exception of a few closer sightings when there was an island or very
shallow water between the seismic operations and the whales (Miller et
al., 1998, 1999). The available data do not provide an unequivocal
estimate of the distance (and received sound levels) at which
approaching bowheads begin to deflect, but this may be on the order of
35 km (21.7 mi).
When the received levels of noise exceed some threshold, cetaceans
will show behavioral disturbance reactions. The levels, frequencies,
and types of noise that will elicit a response vary between and within
species, individuals, locations, and seasons. Behavioral changes may be
subtle alterations in surface, respiration, and dive cycles. More
conspicuous responses include changes in activity or aerial displays,
movement away from the sound source, or complete avoidance of the area.
The reaction threshold and degree of response also are related to the
activity of the animal at the time of the disturbance. Whales engaged
in active behaviors, such as feeding, socializing, or mating, appear
less likely than resting animals to show overt behavioral reactions,
unless the disturbance is perceived as directly threatening.
Masking
Although NMFS believes that some limited masking of low-frequency
sounds (e.g., whale calls) is a possibility during seismic surveys, the
intermittent nature of seismic source pulses (1 second in duration
every 16 to 24 seconds (i.e., less than 7 percent duty cycle)) will
limit the extent of masking. Bowhead whales are known to continue
calling in the presence of seismic survey sounds, and their calls can
be heard between seismic pulses (Greene et al., 1999, Richardson et
al., 1986). Masking effects are expected to be absent in the case of
belugas, given that sounds important to them are predominantly at much
higher frequencies than are airgun sounds.
Injury and Mortality
NMFS and SOI believe that there is no evidence that bowheads or
other marine mammals exposed to seismic sounds in the Arctic have
incurred an injury to their auditory mechanisms. While it is not
positively known whether the hearing systems of marine mammals very
close to an airgun would be at risk of temporary or permanent hearing
impairment, Richardson et al. (1995) notes that TTS is a theoretical
possibility for animals within a few hundred meters of the source. More
recently, scientists have determined that the received level of a
single seismic pulse might need to be ~210 dB re 1 [mu]Pa rms (~221-226
dB pk-pk) in order to produce brief, mild TTS. Exposure to several
seismic pulses at received levels near 200-205 dB (rms) might result in
slight TTS in a small odontocete, assuming the TTS threshold is a
function of the total received pulse energy. Seismic pulses with
received levels of 200-205 dB or more are usually restricted to a
radius of no more than 200 m (656 ft) around a seismic vessel operating
a large array of airguns. For baleen whales, there are no data, direct
or indirect, on levels or properties of sound that are required to
induce TTS. However, according to SOI, there is a strong likelihood
that baleen whales (i.e., bowheads, gray whales and humpback whales)
would avoid the approaching airguns (or vessel) before being exposed to
levels high enough for there to be any possibility of onset of TTS.
For pinnipeds, information indicates that for single seismic
impulses, sounds would need to be higher than 190 dB rms for TTS to
occur while exposure to several seismic pulses indicates that some
pinnipeds may incur TTS at somewhat lower received levels than do small
odontocetes exposed for similar durations. This indicates to NMFS that
the 190-dB safety zone (see Mitigation and Monitoring later in this
document) provides a sufficient buffer to prevent permanent threshold
shift (PTS) in pinnipeds.
A marine mammal within a radius of <=100 m (<=328 ft) around a
typical large array of operating airguns may be exposed to a few
seismic pulses at received levels of [gteqt]205 dB, and possibly more
pulses if the marine mammal moved with the seismic vessel. 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. However, as scientists are reluctant to cause injury
to a marine mammals, 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. Given the possibility that mammals close to an
airgun array might incur TTS, there has been further speculation about
the possibility that some individuals occurring very close to airguns
might incur PTS. Single or occasional occurrences of mild TTS are not
indicative of permanent auditory damage in terrestrial mammals.
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. Acousticians are in general agreement that a
temporary shift in hearing threshold of up to 40 dB due to moderate
exposure times is fully recoverable and does not involve tissue damage
or cell loss. Liberman and Dodds (1987) state, ''... acute threshold
shifts as large as 60 dB are routinely seen in ears in which the
surface morphology of the stereocilia is perfectly normal.''
(Stereocilia are the sensory cells responsible for the sensation of
hearing.). In the chinchilla, no cases of TTS involve the loss of
stereocilia, but all cases of PTS do (Ahroon et al., 1996). Cell death
clearly qualifies as Level A harassment (injury)
[[Page 36049]]
under the MMPA. Because there is no cell death with modest (up to 40
dB) TTS, such losses of sensitivity constitute a temporary impairment
but not an injury, further supporting NMFS' precautionary approach that
establishment of seismic airgun shutdown at 180 dB for cetaceans and
190 dB for pinnipeds, will prevent auditory injury to marine mammals by
seismic airgun sounds.
NMFS notes that planned monitoring and mitigation measures
(described later in this document) have been designed to avoid sudden
onsets of seismic pulses at full power, to detect marine mammals
occurring near the array, and to avoid exposing them to sound pulses
that have any possibility of causing hearing impairment. Moreover, NMFS
does not expect that any marine mammals will be seriously injured or
killed during SOI's seismic survey activities, even if some animals are
not detected prior to entering the 180-dB and 190-dB isopleths (safety
zones) for cetaceans and pinnipeds, respectively. These criteria were
set to approximate a level below where Level A harassment (i.e.,
defined as ``any act of pursuit, torment or annoyance which has the
potential to injure a marine mammal or marine mammal stock in the
wild'') from acoustic sources was believed to begin. Because, a decade
or so ago, scientists did not have information on where PTS might occur
in marine mammals, the High Energy Seismic Survey (HESS) workshop
(HESS, 1997, 1999) set the level to prevent injury to marine mammals at
180 dB. NMFS concurred and determined that TTS, which is the mildest
form of hearing impairment that can occur during exposure to a strong
sound, may occur at these levels (180 dB for cetaceans, 190 dB for
pinnipeds). When a marine mammal experiences TTS, the hearing threshold
rises and a sound must be stronger in order to be heard. TTS can last
from minutes or hours to (in cases of strong TTS) days. For sound
exposures at or somewhat above the TTS threshold, hearing sensitivity
recovers rapidly after exposure to the noise ends. Few data on sound
levels and durations necessary to elicit mild TTS have been obtained
for marine mammals, and none of the published data concern TTS elicited
by exposure to multiple pulses of sound.
Strandings
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 74905 (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 June, 2008 stranding of 30-40 melon-headed whales
(Peponocephala spp), off Madagascar that appears to be associated with
seismic surveys is currently under investigation. One report indicates
that the stranding began prior to seismic surveys starting.
It should be noted that marine mammal strandings recorded in the
Beaufort and Chukchi seas do not appear to be related to seismic
surveys. Finally, if bowhead and gray whales react to sounds at very
low levels by making minor course corrections to avoid seismic noise
and mitigation measures require SOI to ramp-up the seismic array to
avoid a startle effect, strandings are unlikely to occur in the Arctic
Ocean. As a result, NMFS does not expect any marine mammals will incur
serious injury, mortality or strandings in the Arctic Ocean.
Potential Impacts on Affected Species and Stocks of Marine Mammals
According to SOI, the only anticipated impacts to marine mammals
associated with SOI's seismic activities with respect to noise
propagation are from vessel movements and seismic air gun operations.
SOI states that these impacts would be temporary and short term
displacement of seals and whales from within ensonified zones produced
by such noise sources. Any impacts on the whale and seal populations of
the Beaufort and Chukchi Sea activity areas are likely to be short term
and transitory arising from the temporary displacement of individuals
or small groups from locations they may occupy at the times they are
exposed to seismic sounds at the 160-190 dB (or higher) received
levels. As noted elsewhere, it is highly unlikely that animals will be
exposed to sounds of such intensity and duration as to physically
damage their auditory mechanisms. In the case of bowhead whales that
displacement might well take the form of a deflection of the swim paths
of migrating bowheads away from (seaward of) received noise levels
greater than 160 db (Richardson et al., 1999). There is no evidence
that bowheads so exposed have incurred injury to their auditory
mechanisms. Also, there is no evidence that seals are more than
temporarily displaced from ensonified zones and no evidence that seals
have experienced physical damage to their auditory mechanisms even
within ensonified zones.
During the period of seismic acquisition in the Chukchi and
Beaufort seas, most marine mammals are expected to be dispersed
throughout the area. Bowhead whales are expected to be concentrated in
the Canadian Beaufort Sea during much of this time, where they are not
expected to be affected by SOI's seismic program. The peak of the
bowhead whale migration through the Beaufort and Chukchi seas typically
occurs in late August through October, and efforts to reduce potential
impacts during this time will be addressed with the actual start of the
migration and through discussions with the affected whaling
communities. In the Chukchi Sea, the timing of seismic activities will
take place while the whales are widely distributed and would be
expected to occur in very low numbers within the seismic activity area.
If SOI conducts seismic surveys in late September or October in the
Beaufort or Chukchi Sea, bowheads may travel in proximity to the
seismic survey activity areas and hear sounds from vessel traffic and
seismic activities, of which some might be displaced by the planned
activities.
The reduction of potential impacts during the fall bowhead whale
migratory period will be addressed through discussions with the whaling
communities. Starting in late August bowheads may travel in proximity
to SOI's planned Beaufort Sea seismic activity areas and may hear
sounds from vessel traffic and seismic activities, of which some might
be displaced seaward by the planned activities. However, at the present
time, SOI expects to significantly reduce its period of seismic
operations in the Beaufort Sea by remaining in the Chukchi Sea until
mid-September, entering the Beaufort Sea only after the fall
subsistence hunt has concluded and after a significant portion of the
bowhead whales would have left the Canadian Beaufort Sea on their
westward migration to the Chukchi Sea.
In addition, although there was apparently a period of concentrated
feeding in the central Beaufort Sea in September 2007, feeding does not
normally appear to be an important activity by bowheads migrating
through the eastern and central part of the Alaskan Beaufort Sea or the
Chukchi Sea in most years. Sightings of bowhead whales occur in the
summer near Barrow (Moore and DeMaster, 2000), and there are
suggestions that certain areas near Barrow are important feeding
[[Page 36050]]
grounds. In addition, a few bowheads can be found in the Chukchi and
Bering Seas during the summer and Rugh et al. (2003) suggests that this
may be an expansion of the western Arctic stock, although more research
is needed. In the absence of important feeding areas, the potential
diversion of a small number of bowheads away from seismic activities is
not expected to have any significant or long-term consequences for
individual bowheads or their population.
Effects on Individual Arctic Ocean Marine Mammal Species
In order to facilitate the reader's understanding of the knowledge
of impacts of impulsive noise on the principal marine mammal species
that are expected to be affected by SOI's proposed seismic survey
program, NMFS has previously provided a summary of potential impacts on
the bowhead, gray, and beluga whales and the ringed, largha and bearded
seals. This information can be found in the Federal Register (72 FR
31553, June 7, 2007). Information on impacts on marine mammals by
seismic activities can also be found in SOI's IHA application.
Numbers of Marine Mammals Expected to Be Harassed by Seismic Survey
Activities
The methodology used by SOI to estimate incidental take by
harassment by seismic and the numbers of marine mammals that might be
affected in the proposed seismic acquisition activity area in the
Chukchi and Beaufort seas has been presented in SOI's 2008 IHA
application.
In its application, SOI provides estimates of the number of
potential ``exposures'' to sound levels equal to or greater than 160 dB
re 1 [mu]Pa (rms). NMFS clarifies here that, except possibly for
bowhead whales, calculations of the number of exposures by SOI, does
not necessarily indicate that this is the number of Level B harassments
that SOI's seismic activity will take. First, exposure estimates do not
take into account variability between species or within a species by
activity, age or sex. What this means is that not all animals are
expected to react at the same level as its conspecifics, and all
species are not expected to react at the same level, as some species in
the Arctic will respond to sounds differently, if at all, depending
upon whether or not they have good hearing in the same frequency range
as seismic. Second, NMFS believes that SOI's use of the maximum density
estimates for its requested take authorization (see IHA application and
references for details) is overly cautious as it tends to inflate
harassment take estimates to an unreasonably high number and is not
based on good empirical science. NMFS believes that these inflated
numbers have been provided and used by SOI for its Level B harassment
take request in an abundance of caution because they present a worst-
case estimate. NMFS, on the other hand prefers to use the average
density estimate numbers provided in Tables 6-1 through 6-5 in SOI's
IHA application as these are the more realistic and scientifically
supportable estimates. NMFS notes, for example, that the most
comprehensive survey data set on ringed and bearded seals from the
central and eastern Beaufort Sea was conducted on offshore pack ice in
late spring. Density estimates of ringed and bearded seals were based
on counts of seals on the ice during this survey, not in open water
where seismic surveys are conducted. Consequently, the density and
potential take (exposure) numbers for seals in the Beaufort and Chukchi
seas will likely overestimate the number of seals that could be
encountered and/or exposed to seismic airguns because only animals in
the water near the survey area would be exposed to seismic and site
clearance activity sound sources. Because seals would be more widely
dispersed while in open water, NMFS presumes that animal densities
would be less than when seals are concentrated on and near the ice.
Compounding that error, SOI calculated the maximum density for seals as
4 times the average density, which NMFS does not believe is supported
by the best available science.
The estimates for marine mammal ``exposure'' are based on a
consideration of the number of marine mammals that might be appreciably
disturbed during approximately 7974 km (4955 mi) of full 3D seismic
surveys and approximately 4294 km (2668 mi) of mitigation gun activity
in the Chukchi Sea and by approximately 4784 km (2973 mi) of full 3D
seismic surveys and approximately 2576 km (1600 mi) of mitigation gun
(a single small airgun used when the airgun array is not active to
alert marine mammals to the presence of the survey vessel) activity in
the Beaufort Sea. In addition to the 3D seismic program, the shallow
hazards surveys using a 2 10 in\3\ airgun array will be performed along
approximately 1237 km (769 mi) in the Beaufort Sea and approximately
432 km (268 mi) in the Chukchi Sea.
NMFS further notes that the close spacing of neighboring tracklines
within the planned 3D seismic survey areas results in a limited amount
of total area of the Chukchi and Beaufort seas being exposed to sounds
[gteqt] 160 dB while much of the survey area is exposed repeatedly.
This means that the number of non-migratory cetaceans and pinnipeds
exposed to seismic sounds would be less than if the seismic vessel
conducted straight line transects of the sea without turning and
returning on a nearby, parallel track. However, these animals may be
exposed several times before the seismic vessel moves to a new site. In
that regard, NMFS notes that the methodology used by SOI in its
``exposure'' calculations is more valid for seismic surveys that
transect long distances, for those surveys that ``mow the lawn'' (that
is, remain within a relatively small area, transiting back and forth
while shooting seismic). In such situations, the Level B harassment
numbers tend to be highly inflated, if each ``exposure'' is calculated
to be a different animal and not, as here, a relatively small number of
animals residing in the area and being ``exposed'' to seismic sounds
several times during the season. As a result, NMFS believes that SOI's
estimated number of individual exposures does not account for multiple
exposures of the same animal (principally non-migratory pinnipeds)
instead of single animal exposures as the survey conducts a number of
parallel transects of the same area (sometimes called bostrophodontical
surveys) and the fact that the mitigation procedures would serve to
reduce exposures to affected marine mammals.
As mentioned previously, 3D seismic airgun arrays are composed of
identically tuned Bolt-gun sub-arrays operating at 2,000 psi. In
general, the signature produced by an array composed of multiple sub-
arrays has the same shape as that produced by a single sub-array while
the overall acoustic output of the array is determined by the number of
sub-arrays employed. The gun arrangement for the 1,049 square inches
(in2) sub-array is detailed below and is comprised of three subarrays
comprising a total 3,147 in2 sound source. The anticipated radii of
influence of the bathymetric sonars and pinger are less than those for
the air gun configurations described in Attachment A in SOI's IHA
application. It is assumed that, during simultaneous operations of
those additional sound sources and the air gun(s), any marine mammals
close enough to be affected by the sonars or pinger would already be
affected by the air gun(s). In this event, SOI believes that marine
mammals are not expected to exhibit more than short-term and
inconsequential responses, and such responses have not been
[[Page 36051]]
considered to constitute ``taking'' therefore, potential taking
estimates only include noise disturbance from the use of air guns. The
specifications of the equipment, including site clearance activities,
to be used and areas of ensonification are described more fully in
SOI's IHA application (see Attachment B in SOI's IHA application).
Cetaceans
For belugas and gray whales, in both the Beaufort and Chukchi Seas
and bowhead whales in the Chukchi Sea, Moore et al. (2000b and c) offer
the most current data to estimate densities during summer. Density
estimates for bowhead whales in the Beaufort Sea were updated by
information provided by Miller et al. (2002).
Tables 6-1 and 6-2 (Chukchi Sea) and Tables 6-3 and 6-4 (beluga and
bowhead: Beaufort Sea) provide density estimates for the summer and
fall, respectively. Table 6-5 provides a summary of the expected
densities for cetaceans (other than bowheads and belugas) and pinnipeds
during all seasons in the Beaufort Sea. The number of different
individuals of each species potentially exposed to received levels
[gteqt]160 dB re 1 [mu]Pa (rms) within each survey region, time period,
and habitat zone was estimated by multiplying the expected species
density, by the anticipated area to be ensonified to the 160-dB level
in the survey region, time period, and habitat zone to which that
density applies.
The numbers of ``exposures'' were then summed by SOI for each
species across the survey regions, seasons, and habitat zones. Some of
the animals estimated to be exposed, particularly migrating bowhead
whales, might show avoidance reactions before being exposed to
[gteqt]160 dB re 1 [mu]Pa (rms). Thus, these calculations actually
estimate the number of individuals potentially exposed to [gteqt]160 dB
that would occur if there were no avoidance of the area ensonified to
that level.
For the full-3D airgun array, the cross track distance is 2 the
160-dB radius which was measured in 2007 as 8.1 km (5.0 mi) in the
Chukchi Sea and 13.4 km (8.3 mi) in the Beaufort Sea. The mitigation
gun' 160-dB radius was measured at 1370 m (4495 ft) in the Chukchi Sea
and Beaufort seas. For shallow hazards surveys to be performed by the
Henry Christofferson, the 160-dB radius measured in 2007 was equal to
621 m (2037 ft). Using these distances, SOI estimates that the area
ensonified in the Chukchi Sea is approximately 15,000 km\2\ and
approximately 10,100 km\2\ in the Beaufort Sea.
The estimated numbers of potential marine mammal ``exposures'' by
SOI's surveys are presented in Tables 6-6 for the summer/fall period in
the Chukchi Sea, Table 6-7 for bowhead and beluga whales in the U.S.
Beaufort Sea and in Table 6-8 for marine mammals (other than bowheads
and belugas) in the Beaufort Sea. Table 1 in this document (Table 6-9
in the IHA application) summarizes these exposure estimates based on
the 160-dB re 1 [mu]Pa (rms) criteria for cetaceans exposed to impulse
sounds (such as seismic).
SOI's estimates show that the bowhead whale is the only endangered
marine mammal expected to be exposed to noise levels [gteqt] 160 dB
unless, as expected during the fall migratory period, bowheads avoid
the approaching survey vessel before the received levels reach 160 dB.
Migrating bowheads are likely to take avoidance measures, though many
of the bowheads engaged in other activities, particularly feeding and
socializing, probably will not. SOI's estimate of the number of bowhead
whales potentially exposed to [gteqt]160 dB is 1540 animals (9 in the
Chukchi Sea and 1531 in the Beaufort Sea (see Table 1)). Two other
endangered cetacean species that may be encountered in the northern
Chukchi/western Beaufort Sea area, the fin whale and humpback whale,
are estimated by SOI to have two exposures each in the Chukchi Sea.
However, NMFS believes that at least for the fin whale, no animals
would be so exposed given their low ``average'' estimates of densities
in the area.
Most of the cetaceans exposed to seismic sounds with received
levels [gteqt]160 dB would involve bowhead, gray, and beluga whales,
and the harbor porpoise. Average estimates of the number of exposures
of cetaceans by 3D seismic surveys (other than bowheads), in descending
order, are beluga (298), gray whale (183), and harbor porpoise (58).
The regional breakdown of these numbers is shown in Tables 6-6 to 6-8.
Estimates for other species are lower (Table 6-9). These estimates are
also provided in Table 1 in this Federal Register notice.
Pinnipeds
Ringed, spotted, and bearded seals are all associated with sea ice,
and most census methods used to determine density estimates for
pinnipeds are associated with counting the number of seals hauled out
on ice. Correction factors have been developed for most pinniped
species that address biases associated with detectability and
availability of a particular species. Although extensive surveys of
ringed and bearded seals have been conducted in the Beaufort Sea, the
majority of the surveys have been conducted over the landfast ice and
few seal surveys have been in open water. The most comprehensive survey
data set on ringed seals (and bearded seal) from the central and
eastern Beaufort Sea was conducted on offshore pack ice in late spring
(Kingsley, 1986). It is important to note that all proposed activities
will be conducted during the open-water season and density estimates
used here were based on counts of seals on ice. Therefore, densities
and potential take numbers will overestimate the numbers of seals that
would likely be encountered and/or exposed because only the animals in
the water would be exposed to the seismic and clearance activity sound
sources.
The ringed seal is the most widespread and abundant pinniped in
ice-covered arctic waters and ringed seals are expected to account for
the vast majority of marine mammals expected to be encountered, and
hence exposed to airgun sounds with received levels [gteqt]160 dB re 1
[mu]Pa (rms) during SOI's seismic survey. The average estimate is that
13,256 ringed seals might be exposed to seismic sounds with received
levels [gteqt]160 dB. Two additional pinniped species (other than the
Pacific walrus) are expected to be encountered. They are the bearded
seal (592 exposures), and the spotted seal (422 exposures)(see Table 1
in this document or Table 6-9 in the IHA application). The spotted seal
and ribbon seal are unlikely to be encountered during SOI's seismic
surveys.
[[Page 36052]]
TABLE 1. Summary of the Number of Potential Exposures of Marine Mammals to Received Sound Levels in the Water of [gteqt]160 dB During SOI's Proposed
Seismic Program in the Chukchi Sea and Beaufort Sea, Alaska, July - November, 2008. Not all marine mammals will change their behavior when exposed to
these sound levels, although some might alter their behavior somewhat when levels are lower (see text).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Number of Individuals Exposed to Sound Levels [gteqt]160dB
-----------------------------------------------------------------------------------------------------------------------
Species Chukchi Sea Beaufort Sea Total
-----------------------------------------------------------------------------------------------------------------------
Avg. Max. Avg. Max. Avg. Max.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Odontocetes
Monodontidae
Beluga 63 254 234 938 298 1192
Narwhal 0 0 0 0 0 0
Delphinidae
Killer whale 2 6 0 0 2 6
Phocoenidae
Harbor porpoise 57 227 2 6 58 234
Mysticetes
Bowhead Whale \a\ 9 46 1531 1536 1540 1582
Fin whale 2 6 0 0 2 6
Gray whale 182 727 2 6 183 734
Humpback whale 2 6 0 0 2 6
Minke whale 2 6 0 0 2 6
-----------------------------------------------------------------------------------------------------------------------
Total Cetaceans 70 281 1533 1543 1603 1824
Pinnipeds
Bearded seal 270 405 322 1286 592 1691
Ribbon seal 2 6 0 0 2 6
Ringed seal 6951 10827 6305 25221 13256 36047
Spotted seal 361 562 61 243 422 804
-----------------------------------------------------------------------------------------------------------------------
Total Pinnipeds 5678 8836 6687 26750 12366 35586
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ See text for description of bowhead whale estimate for the Beaufort Sea
Potential Marine Mammal Disturbance At Less Than 160 dB Received Levels
During autumn seismic surveys in the Beaufort Sea, migrating
bowhead whales displayed avoidance (i.e., deflection) at distances out
to 20-30 km (12-19 mi) and received sound levels of ~130 dB (rms)
(Miller et al., 1999; Richardson et al., 1999). Therefore, it is
possible that a larger number of bowhead whales than estimated above
may be disturbed to some extent if reactions occur at [gteqt]130 dB
(rms).
However, these references note that 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]Parms. 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
sound pressure level (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, NMFS has noted in the past that minor course changes during
migration are not considered a significant behavioral change and, as
indicated in MMS' 2006 Final PEA, have not been seen at other times of
the year and during other activities. To show the contextu