Small Takes of Marine Mammals Incidental to Specified Activities; Seismic Surveys in the Beaufort and Chukchi Seas off Alaska, 31553-31568 [E7-10953]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 72, Number 109 (Thursday, June 7, 2007)]
[Notices]
[Pages 31553-31568]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E7-10953]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[I.D. 010207A]


Small Takes of Marine Mammals Incidental to Specified Activities; 
Seismic Surveys in the Beaufort and Chukchi Seas off Alaska

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.

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SUMMARY:  NMFS has received an application from Shell Offshore, Inc. 
(SOI) and 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 mid and eastern Beaufort and on pre-lease areas in the 
Northern Chukchi Sea. 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 harassment, small numbers of 
several species of marine mammals between mid-July and November, 2007 
incidental to conducting seismic surveys.

DATES:  Written comments and information must be received no later than 
July 9, 2007.

ADDRESSES:  Written comments on the application should be addressed to 
P. Michael Payne, Chief, Permits, Conservation and Education Division, 
Office of Protected Resources, National Marine Fisheries Service, 1315 
East-West Highway, Silver Spring, MD 20910-3225. The mailbox address 
for providing e-mail comments is PR1.010207A @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. 
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 the address provided here.
    A copy of the NMFS/Minerals Management Service's (MMS) Draft 
Programmatic Environmental ImpactStatement (Draft PDEIS) is available 
on CD from the person listed below (see ADDRESSES) and at: https://
www.mms.gov/alaska/.

FOR FURTHER INFORMATION CONTACT: Kenneth Hollingshead, Office of 
Protected Resources, NMFS, (301) 713-2289 or Brad Smith, NMFS Anchorage 
(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 a complete application followed by a 30-

[[Page 31554]]

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 November 22, 2006, 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 2007 in the mid- 
and eastern-Beaufort and northern Chukchi seas. SOI's 2007 open water 
seismic program includes: (1) Chukchi Sea Deep 3D Seismic, (2) Beaufort 
Sea Deep 3D Seismic; and (3) Beaufort Sea Marine Surveys (including 
site clearance and shallow hazards (sonar, shallow seismic, acoustic 
monitoring studies, seabed topography and environmental monitoring)).
    The deep seismic survey component 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 air gun and 
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 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 Kilabuk, or similar 
ice-class vessel. The Kilabuk will serve as a resupply, fueling support 
of acoustic and marine mammal monitoring, and seismic chase vessel. It 
also is capable of assisting in ice management operations but will not 
deploy seismic acquisition gear.

Plan for Seismic Operations

    SOI plans for the M/V Gilavar to be in the Chukchi Sea in early 
July to begin deploying the acquisition equipment. Seismic acquisition 
is planned to begin on or about July 15, 2007. However, the proposed 
commencement date of July 15 will not occur earlier than that even if 
marine conditions allow since the timing 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 July.
    The approximate area of operations are shown in Figure 1 in SOI's 
IHA application. Data acquisition will continue in the Chukchi Sea 
until ice conditions permit a transit into the Beaufort Sea around 
early August. Seismic acquisition is planned to continue in the 
Beaufort at one of three 3-D areas until early October depending on ice 
conditions. For each of the 3-D areas, the M/V Gilavar will traverse 
the area multiple times until data over the area of interest has been 
recorded. While SOI's application notes that at the conclusion of 
seismic acquisition in the Beaufort Sea, the M/V Gilavar will return to 
the Chukchi Sea and resume recording data there until near the end of 
October, SOI has confirmed that it does not plan to return to the 
Chukchi Sea following completion of its seismic work in the Beaufort 
Sea.
    The proposed Beaufort Sea activities are proposed to commence in 
August and continue until weather precludes further seismic work. The 
deep seismic program will take place in OCS waters on SOI's leases 
beginning east of the Colville River delta to east of the village of 
Kaktovik. Within this area, SOI has acquired four separate groups of 
lease blocks, totaling 85 leases. The timing of activities is scheduled 
to avoid any conflict with the Beaufort Sea bowhead whale subsistence 
hunt conducted by the Alaska Eskimo Whaling Commission's (AEWC) 
villages.

Chukchi Sea Deep 3D Seismic

    The proposed deep seismic survey in the Chukchi Sea will occur 
before the survey activity in the Beaufort Sea. As sea ice coverage 
conditions allow, seismic activity will begin approximately July 15 and 
continue to early-to-mid August when the M/V Gilavar and M/V Kilabuk, 
or similar vessel, will transit to the Beaufort Sea to start work on a 
deep seismic survey on SOI lease-holdings in the mid and eastern 
Beaufort. The M/V Peregrine or similar vessel will conduct crew change 
transfers. After mid-October when sea ice conditions in the mid and 
eastern Beaufort Sea make further survey work there impractical, the 
survey activity will leave the Arctic Ocean. The dates indicated here 
represent what might occur under ideal conditions for performing marine 
seismic work whereas the actual dates will depend on sea ice and 
weather conditions as they occur in summer and mid-autumn of 2007.
    The geographic region where the proposed deep seismic survey will 
occur is the Chukchi Sea MMS OCS Program Area designated as Chukchi Sea 
Sale 193 (1989) and the proposed 2002-2007 Chukchi Sea Program Area 
(See Figure 1, MMS Chukchi Sea Sale 193). Since the Chukchi deep 
seismic program is being conducted most likely as a pre-lease activity, 
the exact locations where operations will occur remain confidential for 
business competitive reasons. That is, the seismic data acquired will 
be used by SOI to determine what leases it will bid on in a forth-
coming competitive lease sale. In general, however, seismic acquisition 
will take place well offshore from the Alaska coast beyond any 
exclusion areas stipulated in the MMS Chukchi Sea Planning Area Oil and 
Gas Lease Sale EIS 193 on OCS waters averaging greater than 40 meter 
(m) depths.

Beaufort Sea Deep 3D Seismic

    The deep seismic program will take place in OCS waters on SOI 
leases beginning east of the Colville River delta to east of the 
village of Kaktovik (see Figure 2 in SOI's application). Within this 
area, SOI has acquired four separate groups of lease blocks, totaling 
85 leases. The program is planned to occur during open-water from late 
July to the end of October.
    SOI plans to run approximately 6,437 km (4000 mi) of seismic 
surveys in the Chukchi and Beaufort Seas.

Beaufort Sea Marine Surveys

    Marine surveys will include site clearance and shallow hazards 
surveys of potential exploratory drilling locations within SOI's OCS 
lease areas and a potential pipeline corridor within and outside of SOI 
OCS lease blocks as required by MMS regulations. Site clearance surveys 
are confined to small specific areas within OCS blocks. Site clearance 
surveys are to take place at specific sites on various SOI leases from 
the Sivulliq lease block north of Pt. Thomson east to the Olympia block 
north of Barter Island (Figure 2 in SOI's IHA application). All of 
these sites are in OCS waters. Additional site clearance studies are 
planned over a corridor from the center of the Sivulliq lease block 
south to Pt. Thomson, a distance of approximately 22.4 km (14 mi). Site 
clearance surveys will be conducted contemporaneously with SOI's 3D 
seismic survey program.
    The site clearance and shallow hazards surveys will be conducted by 
the M/V Henry Christoffersen, the same vessel used during SOI's 2006 
site clearance and shallow hazard surveys). It is proposed that the 
same acoustic

[[Page 31555]]

instrumentation during 2006 will again be used during 2007: (1) Dual 
frequency subbottom profiler Datasonics CAP6000 Chirp II (2-7kHz or 8-
23 kHz); Medium penetration subbottom profiler, Datasonics SPR-1200 
Bubble Pulser (400 (hertz [Hz]); (2) hi-resolution multi-channel 2D 
system, 240 cubic inches (in\3\)(4X60) gun array (0-150 Hz); (3) multi-
beam bathymetric sonar, Seabat 8101 (240 Hz); and (4) side-scan sonar 
system, Datasonics SIS-1500 (190 - 210 kHz). These systems are 
described in SOI's IHA application.
    These systems will be used in order to examine and measure 
bathymetry, seabed topography, potential geohazards and other seabed 
characteristics (i.e. boulder patches). The site-specific locations of 
site clearance and shallow hazard surveys have not been definitively 
set, although they will occur within the area outlined in Figure 2 in 
SOI's IHA application. In addition, several (more than 10) sonabouys 
(passive acoustic monitoring equipment) are to be positioned in and 
around potential drilling locations within the Sivulliq lease block. 
SOI states that the timing of the activity is scheduled to avoid 
conflict with the Beaufort Sea subsistence hunts conducted by the 
Whaling Captain's Associations of Barrow, Kaktovik, and Nuiqsut (see 
Mitigation).
    The multi-beam bathymetric sonar and the side-scan sonar systems 
operate at frequencies greater than 180 kHz, the highest frequency 
considered by knowledgeable marine mammal biologists to be of possible 
influence to marine mammals. No measurements of those two sources are 
planned, as the recording equipment has a practical upper limit of 90 
kHz. As determined during the sound measurement process, there should 
be no exclusion zones for seals or whales during operation of those two 
sources.
    Acoustic systems similar to the ones proposed for use by SOI have 
been described in detail 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 detailed description of the work proposed by SOI for 2007 is 
contained in SOI's application which is available for review (see 
ADDRESSES). A description of SOI's data acquisition program and 
WesternGeco's air-gun array 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) and is no different than previous programs.

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

    Shell will 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 gun arrangement for each of the three 1049-in\3\ sub-array is 
detailed in Shell's application. As indicated in the application's 
diagram, each sub-array is composed of six tuning elements; two 2-gun 
clusters and four single guns. The standard configuration of a source 
array for 3D 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

    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 as there 
are no differences. 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.

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).

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 PEA. Information on these 
marine mammal species can also be found in NMFS Stock Assessment 
Reports (SARS). The Alaska SARS document is available at: https://
www.nmfs.noaa.gov/pr/pdfs/sars/ak2005.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

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source of noise. The physical presence of vessels and aircraft could 
also lead to non-acoustic disturbance or avoidance 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 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

    SOI (2006) states that the only anticipated impacts to marine 
mammals associated with noise propagation from vessel movement, seismic 
airgun operations, and seabed profiling would be the temporary and 
short term displacement of seals and whales from within ensonified 
zones produced by such noise sources. 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 lower than 160 db (Richardson et al., 1999). The cited and other 
studies conducted to test the hypothesis of the deflection response of 
bowheads have determined that bowheads return to the swim paths they 
were following at relatively short distances after their exposure to 
the received sounds. SOI believes that there is no evidence that 
bowheads so exposed have incurred injury to their auditory mechanisms. 
Additionally, SOI cites Richardson and Thomson [eds]. (2002) that there 
is no conclusive evidence that exposure to sounds exceeding 160 db have 
displaced bowheads from feeding activity.
    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). It is also uncertain how far beyond (west of) the 
seismic operation the seaward deflection persists (Miller et al., 
1999). In one study, although very few bowheads approached within 20 km 
(12.4 mi) of the operating seismic vessel, the number of bowheads 
sighted within that area returned to normal within 12-24 hours after 
the airgun operations ended (Miller et al., 1999).
    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 (Western Geophysical, 2000).
    Hearing damage is not expected to occur during the SOI seismic 
survey project. It is not definitively known whether the hearing 
systems of marine mammals very close to an airgun would be at risk of 
temporary or permanent hearing impairment, but TTS is a theoretical 
possibility for animals within a few hundred meters of the source 
(Richardson et al., 1995). However, planned monitoring and mitigation 
measures to detect marine mammals occurring near the array (described 
later in this document) are designed to avoid sudden onsets of seismic 
pulses at full power. These measures are likely to prevent animals from 
being exposed to sound pulses that have any possibility of causing 
hearing impairment.
    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 among 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, are less 
likely than resting animals to show overt behavioral reactions, unless 
the disturbance is directly threatening.
    The following species summaries are provided by NMFS to facilitate 
understanding of our knowledge of impulsive noise impacts on the 
principal marine mammal species that are expected to be affected.

Bowhead Whales

    Seismic pulses are known to cause strong avoidance reactions by 
many of the bowhead whales occurring within a distance of a few 
kilometers, including changes in surfacing, respiration and

[[Page 31557]]

dive cycles, and may sometimes cause avoidance or other changes in 
bowhead behavior at considerably greater distances (Richardson et al., 
1995; Rexford, 1996; MMS, 1997). Studies conducted prior to 1996 
(Reeves et al., 1984, Fraker et al., 1985, Richardson et al., 1986, 
Ljungblad et al., 1988) have reported that, when an operating seismic 
vessel approaches within a few kilometers, most bowhead whales exhibit 
strong avoidance behavior and changes in surfacing, respiration, and 
dive cycles. In these studies, bowheads exposed to seismic pulses from 
vessels more than 7.5 km (4.7 mi) away rarely showed observable 
avoidance of the vessel, but their surface, respiration, and dive 
cycles appeared altered in a manner similar to that observed in whales 
exposed at a closer distance (Western Geophysical, 2000). In three 
studies of bowhead whales and one of gray whales during this period, 
surfacing-dive cycles were unusually rapid in the presence of seismic 
noise, with fewer breaths per surfacing and longer intervals between 
breaths (Richardson et al., 1986; Koski and Johnson, 1987; Ljungblad et 
al., 1988; Malme et al., 1988). This pattern of subtle effects was 
evident among bowheads 6 km to at least 73 km (3.7 to 45.3 mi) from 
seismic vessels. However, in the pre-1996 studies, active avoidance 
usually was not apparent unless the seismic vessel was closer than 
about 6 to 8 km (3.7 to 5.0 mi)(Western Geophysical, 2000).
    Inupiat whalers believe that migrating bowheads are sometimes 
displaced at distances considerably greater than suggested by pre-1996 
scientific studies (Rexford, 1996) previously mentioned in this 
document. Also, whalers believe that avoidance effects can extend out 
to distances on the order of 30 miles (48.3 km), and that bowheads 
exposed to seismic also are ``skittish'' and more difficult to 
approach. The ``skittish'' behavior may be related to the observed 
subtle changes in the behavior of bowheads exposed to seismic pulses 
from distant seismic vessels (Richardson et al., 1986).

Gray Whales

    The reactions of gray whales to seismic pulses are similar to those 
documented for bowheads during the 1980s. Migrating gray whales along 
the California coast were noted to slow their speed of swimming, turn 
away from seismic noise sources, and increase their respiration rates. 
Malme et al. (1983, 1984, 1988) concluded that approximately 50 percent 
of the migrating gray whales showed avoidance when the average received 
pulse level was 170 dB (re 1 microPa). By some behavioral measures, 
clear effects were evident at average pulse levels of 160+dB; less 
consistent results were suspected at levels of 140-160 dB. Recent 
research on migrating gray whales showed responses similar to those 
observed in the earlier research when the source was moored in the 
migration corridor 2 km (1.2 mi) from shore. However, when the source 
was placed offshore (4 km (2.5 mi) from shore) of the migration 
corridor, the avoidance response was not evident on track plots (Tyack 
and Clark, 1998).

Beluga

    The beluga is the only species of toothed whale (Odontoceti) 
expected to be encountered in the Beaufort Sea. Belugas have poor 
hearing thresholds at frequencies below 200 Hz, where most of the 
energy from airgun arrays is concentrated. Their thresholds at these 
frequencies (as measured in a captive situation), are 125 dB re 1 
microPa or more depending upon frequency (Johnson et al., 1989). 
Although not expected to be significantly affected by the noise, given 
the high source levels of seismic pulses, airgun sounds sometimes may 
be audible to beluga at distances of 100 km (62.1 mi)(Richardson and 
Wursig, 1997), and perhaps further if actual low-frequency hearing 
thresholds in the open sea are better than those measured in captivity 
(Western Geophysical, 2000). The reaction distance for beluga, although 
presently unknown, is expected to be less than that for bowheads, given 
the presumed poorer sensitivity of belugas than that of bowheads for 
low-frequency sounds (Western Geophysical, 2000).

Ringed, Largha and Bearded Seals

    No detailed studies of reactions by seals to noise from open water 
seismic exploration have been published (Richardson et al., 1995). 
However, there are some data on the reactions of seals to various types 
of impulsive sounds (LGL and Greeneridge, 1997, 1998, 1999a; J. Parsons 
as quoted in Greene, et al. 1985; Anon., 1975; Mate and Harvey, 1985). 
These studies indicate that ice seals typically either tolerate or 
habituate to seismic noise produced from open water sources.
    Underwater audiograms have been obtained using behavioral methods 
for three species of phocinid seals, ringed, harbor, and harp seals. 
These audiograms were reviewed in Richardson et al. (1995) and Kastak 
and Schusterman (1998). Below 30-50 kHz, the hearing threshold of 
phocinids is essentially flat, down to at least 1 kHz, and ranges 
between 60 and 85 dB (re 1 microPa @ 1 m). There are few data on 
hearing sensitivity of phocinid seals below 1 kHz. NMFS considers 
harbor seals to have a hearing threshold of 70-85 dB at 1 kHz (60 FR 
53753, October 17, 1995), and recent measurements for a harbor seal 
indicate that, below 1 kHz, its thresholds deteriorate gradually to 97 
dB (re 1 microPa @ 1 m) at 100 Hz (Kastak and Schusterman, 1998).
    While no detailed studies of reactions of seals from open-water 
seismic exploration have been published (Richardson et al., 1991, 
1995), some data are available on the reactions of seals to various 
types of impulsive sounds (see LGL and Greeneridge, 1997, 1998, 1999a; 
Thompson et al. 1998). These references indicate that it is unlikely 
that pinnipeds would be harassed or injured by low frequency sounds 
from a seismic source unless they were within relatively close 
proximity of the seismic array. For permanent injury, pinnipeds would 
likely need to remain in the high-noise field for extended periods of 
time. Existing evidence also suggests that, while seals may be capable 
of hearing sounds from seismic arrays, they appear to tolerate intense 
pulsatile sounds without known effect once they learn that there is no 
danger associated with the noise (see, for example, NMFS/Washington 
Department of Wildlife, 1995). In addition, they will apparently not 
abandon feeding or breeding areas due to exposure to these noise 
sources (Richardson et al., 1991) and may habituate to certain noises 
over time.

Numbers of Marine Mammals Expected to Be Taken

    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 are presented here. The density estimates for 
the species covered under this proposed IHA are based on the estimates 
developed by LGL (2005) and used here for consistency. Density 
estimates are based on the data from Moore et al. (2000) on summering 
bowhead, gray, and beluga whales in the Beaufort and Chukchi Seas, and 
relevant studies on ringed seal estimates including Stirling et al. 
(1982) and Kingsley (1986).
    In its application, SOI provides estimates of the number of 
potential ``exposures'' to sound levels greater than 160 dB re 1 
microPa (rms) and greater than 170 dB. SOI states that while the 160-dB 
criterion applies to all species of cetaceans and pinnipeds, SOI 
believes that a 170-dB criterion should

[[Page 31558]]

be considered appropriate for delphinid cetaceans and pinnipeds, which 
tend to be less responsive, whereas the 160-dB criterion is considered 
appropriate for other cetaceans (LGL, 2005). However, NMFS has noted in 
the past that it is unaware of any empirical evidence to indicate that 
some delphinid species do not respond at the lower level (i.e., 160 
dB). As a result, NMFS will estimate Level B harassment take levels 
based on the 160 dB criterion.
    The estimates for marine mammal exposure are based on a 
consideration of the number of marine mammals that might be disturbed 
appreciably by as much as 6,437 km (4000 mi) of seismic surveys in 
Beaufort Sea and/or the Chukchi Sea. Source arrays are composed of 
identically tuned Bolt gun sub-arrays operating at 2,000 psi, air 
pressure. 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 (in\3\) sub-array is detailed below and is comprised of 
three subarrays comprising a total 3,147 in\3\ 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 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 whale in the Beaufort Sea were taken from Miller 
et al., 2002. Table 6-1 in SOI's IHA application gives the average and 
maximum densities for each cetacean species likely to occur within the 
project areas based on the density estimates developed and corrected as 
needed by LGL for the Beaufort and Chukchi Seas (LGL, 2005), however, 
these estimates were based on surveys of offshore waters (less than 100 
m (328 ft) in depth). However, all seismic activities within the 
seismic activity areas proposed under this IHA will occur in waters 
between 20 and 40 m (65.6 and 131.2 ft) in depth. The estimated numbers 
of potential exposures presented in Tables 1 and 2 (Tables 6-3 and 6-4 
in SOI's IHA application) are based on the 160 dB re 1 microPa (rms) 
criteria for most cetaceans (except for this geographic area, bowhead 
whales), because this range is assumed to be the sound source level at 
which marine mammals may change their behavior sufficiently to be 
considered ``taken by harassment.''

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. Although the estimated numbers of potential exposures 
presented in Tables 1 and 2 (Tables 6-3 and 6-4 in the IHA application) 
are based on two sound source ranges (greater than 160 dB and greater 
than 170 dB re 1 microPa [rms]), for most pinnipeds, SOI believes that 
the 170 dB threshold should be used to determine ``take by harassment'' 
because this range is assumed to be the sound source level at which 
most pinnipeds may change their behavior in reaction to increased sound 
exposure.

Exposure Calculations for Cetaceans and Pinnipeds

    Except for bowheads in the Beaufort Sea, number of exposures of a 
particular species to sound levels between 160 dB and 180 dB re 1 
microPa (rms) was calculated by multiplying: (1) the expected species 
density average and maximum), taken from LGL (2005); (2) the maximum 
anticipated total line-km of operations in the Chukchi and/or Beaufort 
Seas the three 1,049 in\3\ subarrays (6,437 km); and (3) the cross-
track distances within which received sound levels are predicted to be 
greater than 160 dB and greater than 170 dB.
    Distances of sound propagation are taken from direct measurement of 
sound levels at distances from the M/V Gilavar in the Chukchi Sea 
during the 2006 open water season. Shell estimates the sound level 
output radii (rms)) for a 3147 in\3\ source array at a depth of 6 m (20 
ft):
    160 dB (rms) :: 8400 m/27559 ft
    180 dB (rms) :: 1200 m/3937 ft
    190 dB (rms) :: 440 m/1444 ft.
    For bowhead whales in the Beaufort Sea, Richardson et al. (2002) 
provide estimates of densities specific to a given area (subdivided 
east to west and by depth) and time (two week intervals during summer 
and fall). The total number of individuals expected to be in the 
specific area where seismic operations are to occur in the Beaufort Sea 
is multiplied by that portion of the area expected to be ensonified 
above 160 dB.
    Estimates of numbers of cetaceans and pinnipeds exposed to sound 
levels greater than 160 and 170 dB resulting from seismic acquisition 
activities in the Chukchi Sea are presented in Table 1 (Table 6-3 in 
SOI's IHA application). Estimates of exposure levels for the Beaufort 
Sea are presented in Table 2 (Table 6-4 in SOI's IHA application).

[[Page 31559]]



                                    Table 1. Estimated Exposures and Requested Take Levels for Chukchi Sea Operations
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                Average                                                  Maximum                                              Requested
                                Density     190 dB     180 dB     170 dB     160 dB      Density     190 dB    180 dB    170 dB    160 dB       Take
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cetaceans
  bowhead whales                0.0011    .........  17         47         119        0.006         ........  93        255       649       649
  gray whale                   0.0018     .........  28         77         195        0.0072        ........  112       306       779       779
  Beluga                       0.0034     .........  53         145        368        0.0135        ........  209       574       1,460     1,460
  killer whale                 0.0001     .........  2          5          11         0.0004        ........  7         17        44        44
  Minke whale                  0.0001     .........  2          5          11         0.0004        ........  7         17        44        44
  Fin whale                    0          .........  0          0          0          0.0001        ........  2         5         11        11
Pinnipeds
  ringed seal                  0.0234     14         362        995        .........  0.0935        53        1,445     3,973     ........  3,973
  spotted seal                 0.0002     1          4          9          .........  0.0009        1         14        39        ........  39
  bearded seal                 0.0093     6          144        396        .........  0.037         21        572       1573      ........  1573
--------------------------------------------------------------------------------------------------------------------------------------------------------


                                   Table 2. Estimated Exposures and Requested Take Levels for Beaufort Sea Operations
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                Average                                                  Maximum                                              Requested
                                Density     190 dB     180 dB     170 dB     160 dB      Density     190 dB    180 dB    170 dB    160 dB       Take
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cetaceans
  bowhead whales                NA        .........  .........  .........  .........  2,004.236     ........  172       473       1203      1203
  gray whale                   0.0001     .........  2          5          11         0.0004        ........  7         17        44        44
  Beluga                       0.0068     .........  106        289        736        0.0135        ........  209       574       1,460     1,460
  Harbor Porpoise              0          .........  0          0          0          0.0002        ........  4         9         22        22
Pinnipeds
  ringed seal                  0.3547     201        5481       15071      .........  0.7094        402       10,961    30,141    ........  30,141
  spotted seal                 0.0037     3          58         158        .........  0.0149        9         231       634       ........  634
  bearded seal                 0.0181     11         280        770        .........  0.0362        21        560       1,539     ........  1,539
--------------------------------------------------------------------------------------------------------------------------------------------------------


                             Table 3. Estimated Exposures and Requested Take Levels for Beaufort Sea Henry ''C'' Operations
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                  Average                                                       Maximum
                                  Density     190 dB      180 dB      170 dB      160 dB        Density       190 dB      180 dB      170 dB     160 dB
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cetaceans
  bowhead whales                 NA         ..........  ..........  ..........  ..........  2004.236        ..........  48          126        315
  gray whale                    0.0001      ..........  1           1           1           0.0004          ..........  1           1          2
  Beluga                        0.0068      ..........  3           7           18          0.0135          ..........  6           14         35
  Harbor Porpoise               0           ..........  0           0           0           0.0002          ..........  1           1          1
Pinnipeds
  ringed seal                   0.3547      49          135         359         898         0.7094          98          270         718        .........
  spotted seal                  0.0037      1           2           4           ..........  0.0149          3           6           16         .........
  bearded seal                  0.0181      3           7           19          ..........  0.0362          5           14          37         .........
--------------------------------------------------------------------------------------------------------------------------------------------------------

Beaufort Sea: Marine Surveys

    In addition to potential impacts from seismic surveys on Beaufort 
Sea marine mammals, SOI and NMFS anticipate that there is also a 
potential for marine mammals to be impacted by SOI's marine surveys (as 
described previously in this document). SOI determined that the air gun 
cluster on the M/V Henry Christoffersen was the strongest sound source 
on the vessel. Based on sound field measurements, the following 
distances were calculated: 190 dB - 89 m (292 ft); 180 dB - 248 m (814 
ft); and 160 dB - 1,750 m (5741 ft). As explained in SOI's application, 
SOI has calculated a 50 percent margin factor and recommends that these 
zones be amended to the following: 190 dB - 120 m (394 ft), 180 dB - 
330 m (1083 ft); and 160 dB - 2,220 m (7218 ft). Using similar 
methodology as for the M/V Gillivar, Table 3 (Table 6-6 in SOI's IHA 
application) provides estimates of marine mammal sound exposures at 
these SPLs for the M/V Henry Christoffersen.

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 Sea activity area 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 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). This study and others conducted to test the 
hypothesis of the deflection response of bowheads have determined that 
bowheads return to the swim paths they were following at relatively 
short distances after their exposure to the received sounds. There is 
no evidence that bowheads so exposed have incurred injury to their 
auditory mechanisms. Additionally, there is no conclusive

[[Page 31560]]

evidence that exposure to sounds exceeding 160 db have displaced 
bowheads from feeding activity (Richardson, W.J. and D.H. Thomson 
[eds]. 2002).
    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, most marine mammals would 
be dispersed throughout the area. The peak of the bowhead whale 
migration through the Chukchi Sea typically occurs in October, and 
efforts to reduce potential impacts during this time will be addressed 
with the actual start of the migration and with the whaling 
communities. The timing of seismic activities in the Chukchi Sea will 
take place when the whales are widely distributed and would be expected 
to occur in very low numbers within the seismic activity area. Starting 
in late August bowheads may travel in proximity to the aforementioned 
activity area and hear sounds from vessel traffic and seismic 
activities, of which some might be displaced seaward by the planned 
activities.
    The peak of the bowhead whale migration through the Beaufort Sea 
typically occurs in October, and efforts to reduce potential impacts 
during this time will be addressed with the actual start of the 
migration and with the whaling communities. The timing of seismic 
activities in the eastern U.S. Beaufort Sea will take place when the 
whales are not present, or in very low numbers. Starting in late August 
bowheads may travel in proximity to SOI's seismic activity areas and 
hear anthropogenic sounds from vessel traffic and seismic activities. 
Some bowheads may be displaced seaward by the planned activities.
    In addition, feeding does not appear to be an important activity by 
bowheads migrating through the Chukchi Sea or the eastern and central 
part of the Alaskan Beaufort 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 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 known important 
feeding areas in the U.S. Beaufort Sea, 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. Bowheads, gray, or beluga whales are not 
predicted to be excluded from any habitat.

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 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 LGL 
(2005; University of Alaska-Fairbanks Seismic Survey across Arctic 
Ocean at https://www.nmfs.noaa.gov/pr/permits/incidental.htm#iha), and 
includes a summary of direct mortality (pathological/physiological) and 
indirect (behavioral) effects.
    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 standard 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 
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.

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 of the area. 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 related how whales also appear 
``angry'' due to seismic noise, making whaling more dangerous.
    This potential impact on subsistence uses of marine mammals is 
proposed 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. Under a CAA, the times and 
locations of seismic and other noise producing sources would 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 survey activities will also be scheduled to avoid the 
traditional

[[Page 31561]]

subsistence beluga hunt which annually 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 the whale species for subsistence uses.
    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 seismic operations will not 
begin until after July 15, 2007 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 15, 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 the past few years, a small number of bowheads have also been taken 
by coastal villages along the Chukchi coast. 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 have been incorporated 
into the CAA established between SOI and WesternGeco, the AEWC, and the 
Barrow Whaling Captains Association.
    Beluga whales may also be taken sporadically for subsistence needs 
by coastal villages, but traditionally are taken in small numbers very 
near the coast. Because the seismic surveys will be conducted at least 
12 miles (25 km) offshore, impacts to subsistence uses of bowheads are 
not anticipated. However, SOI will establish ``communication stations'' 
in the villages to monitoring 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 notes in its IHA application that 
POC meetings occurred in Barrow and Nuiqsut on October 16 and 17, 2006, 
and follow-up meetings are planned for the period May or June 2007 in 
these communities. SOI is working with all public and private 
organizations to hold a series of meetings in Kaktovik during 2006/
2007. The communities of Point Hope, Point Lay and Wainwright have met 
with SOI to discuss the results of the 2006 survey activities in the 
Chukchi Sea, followed by another series of POC meetings in May or June 
2007. Following those meetings, a POC report will be prepared.
    SOI hopes that a CAA will result from these meetings. 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 the 2007 CAA, 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 must make a determination under the 
MMPA 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 by seismic activities 
is expected to be impacts from noise on bowhead whales during its 
westward fall feeding and migration 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).
    However, it should be understood that while a signed CAA assists 
NMFS in making 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.

Proposed Mitigation and Monitoring

    As part of its application, SOI has proposed implementing a marine 
mammal mitigation and monitoring program 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 marine mammals, 
and received levels should they be detectable using bottom-founded 
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

    On February 7, 2007, SOI submitted its proposed mitigation and 
monitoring program for SOI's seismic programs in the Chukchi and 
Beaufort seas. 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; (