Small Takes of Marine Mammals Incidental to Specified Activities; Seismic Surveys in the Beaufort and Chukchi Seas off Alaska, 26055-26069 [06-4172]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 71, Number 85 (Wednesday, May 3, 2006)]
[Notices]
[Pages 26055-26069]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 06-4172]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[I.D. 020306A]


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 two applications from Shell Offshore, Inc. 
and WesternGeco, Inc. (Shell) for Incidental Harassment Authorizations 
(IHAs) to take small numbers of marine mammals, by harassment, 
incidental to conducting a marine geophysical program, including deep 
seismic surveys, on oil and gas lease blocks located on Outer 
Continental Shelf (OCS) waters in the mid- and eastern-Beaufort Sea 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 a single IHA to Shell to take, by Level B harassment, small 
numbers of several species of marine mammals between July and November, 
2006 incidental to conducting seismic surveys.

DATES:  Comments and information must be received no later than June 2, 
2006.

ADDRESSES:  Comments on the application should be addressed to the 
Chief of the Permits, Conservation and Education Division, Office of 
Protected Resources, National Marine Fisheries Service, 1315 East-West 
Highway, Silver Spring, MD 20910-3225, or by telephoning one of the 
contacts listed here. The mailbox address for providing email comments 
is PR1.020306A@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's (MMS) Programmatic 
Environmental Assessment (PEA) is available on-line at: https://
www.mms.gov/alaska/ref/pea_be.htm .
    Documents cited in this document, that are not available through 
standard public library access, may be viewed, by appointment, during 
regular business hours at this address.

FOR FURTHER INFORMATION CONTACT:  Kenneth Hollingshead or Jolie 
Harrison, Office of Protected Resources, NMFS, (301) 713-2289.

SUPPLEMENTARY INFORMATION:

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce to allow, upon request, the 
incidental, but not intentional, taking of small numbers of marine 
mammals by U.S. citizens who engage in a specified activity (other than 
commercial fishing) within a specified geographical region if certain 
findings are made and either regulations are issued or, if the taking 
is limited to harassment, a notice of a proposed authorization is 
provided to the public for review.
    An authorization shall be granted if NMFS finds that the taking 
will have a negligible impact on the species or stock(s) and will not 
have an unmitigable adverse impact on the availability of the species 
or stock(s) for subsistence uses and that the permissible methods of 
taking and requirements pertaining to the mitigation, monitoring and 
reporting of such 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

[[Page 26056]]

mammals. Within 45 days of the close of the comment period, NMFS must 
either issue or deny issuance of the authorization.

Summary of Request

    On November 16, 2005, NMFS received two applications from Shell for 
the taking, by Level B harassment, of several species of marine mammals 
incidental to conducting a marine seismic survey program during 2006 in 
the mid- and eastern-Beaufort and northern Chukchi seas. The deep 
seismic survey component of the program will be conducted from 
WesternGeco's vessel the M/V Gilavar. Detailed specifications on this 
seismic survey vessel are provided in Shell's application (Attachment A 
- Seismic Survey, Overview/Description). These specifications include: 
(1) complete descriptions of the number and lengths of the streamers 
which form the airgun 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 sails downline in the survey area. The M/
V Gilavar will tow up to 6 hydrophone 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 (m; 1181 ft). The seismic data acquisition vessel will be 
supported by the M/V Alex Gordon, which will serve to resupply and re-
fuel the M/V Gilavar. The M/V Alex Gordon is also capable of ice 
management should that be required. The M/V Alex Gordon will not deploy 
seismic acquisition gear.

Plan for Seismic Operations

    It is planned that the M/V Gilavar will be in the Chukchi Sea in 
early July to begin deploying the acquisition equipment. Seismic 
acquisition is planned to begin on or about July 10, 2006. The 
approximate areas of operations are shown in Appendix 4 in Shell's IHA 
application. 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. These 
3-D areas are shown in Appendix 5 in Shell's application. For each of 
the 3-D areas, the M/V Gilavar will traverse the area multiple times 
until data on the area of interest has been recorded. 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 all seismic 
lines are completed or weather prevents data collection.
    The proposed Beaufort Sea deep seismic, site clearance, shallow 
hazard surveys and geotechnical activities are proposed to commence in 
August and continue until weather precludes further seismic work. The 
timing is scheduled to avoid any conflict with the Beaufort Sea 
subsistence hunting conducted by the Alaska Eskimo Whaling Commission's 
(AEWC) villages.
    In summary, the proposed Chukchi deep seismic survey will occur in 
two phases. Phase 1 will commence sometime after June 15, 2006, as sea 
ice coverage conditions allow and will continue through July to early 
August, 2006. Phase 2 of the Chukchi deep seismic survey will occur 
upon completion of the Beaufort Sea survey sometime after mid-October 
and continue until such time as sea ice and weather conditions preclude 
further work, probably sometime in mid- to late-November, 2006. Shell 
plans to run approximately 5556 km (3452 mi) of surveys in the Chukchi 
Sea and a similar survey length in the Beaufort Sea.
    Alternatively, if ice conditions preclude seismic operations in the 
Beaufort Sea, Shell proposes to continue its seismic program in the 
Chukchi Sea through mid- to late-November, 2006, or approximately 5.5 
months. This scenario takes into account that approximately twice as 
many seismic line miles would be completed during this time in the 
Chukchi Sea. Under this scenario approximately 6000 nm (6905 stat mi; 
11,112 km) of seismic line miles could be completed in the Chukchi Sea.
    A detailed description of the work proposed by Shell for 2006 is 
contained in the two applications which are available for review (see 
ADDRESSES).

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 proposes 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 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.
    Shell's application provides illustrations of the time series and 
amplitude spectrum for the far-field signature and the computed 
acoustic emission pattern for the vertical inline and crossline planes 
for the 3147 in3 array with guns at a depth of 6 m (20

[[Page 26057]]

ft). The signature for this array was first computed using GSAP, 
WesternGeco's in house signature modelling software. Based on this 
model, Shell estimates the sound level output radii (root-mean-squared 
(rms)) for a 3147 in3 source array at a depth of 6 m (20 ft):
     160 dB (rms) :: < 650 m/2133 ft
     170 dB (rms) :: < 425 m/1394 ft
     180 dB (rms) :: < 225 m/738 ft
     190 dB (rms) :: < 120 m/394 ft.
    Subsequent to submitting its application, Shell contracted with 
JASCO to model sound source characteristics using a different model. 
The JASCO parabolic equation model is believed by Shell and NMFS to be 
superior in these waters because it accounts for bathymetry effects, 
water properties, and the geoacoustic properties of seabed layers. The 
JASCO-modeled radii are based on the worst case model predictions. For 
this model, the proposed 180-dB and 190-dB radii are 1.5 km (0.9 mi) 
and 0.5 km (0.3mi), respectively. This model will be used by Shell and 
NMFS to estimate sound level isopleths and radii for rms sound level 
thresholds between 120 and 190 dB at six proposed survey locations for 
the proposed airgun arrays. In addition, these modeled radii estimates 
will be multiplied by a safety margin of 1.5 to obtain conservative 
exclusion radii for marine mammal safety until empirical sound field 
verification measurements are completed within the first few days of 
seismic shooting.
    An explanation for the indicated sound pressure levels (SPLs) is 
provided later in this document (see Impacts to Marine Mammals).

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. 
Additional information can be found in the MMS PEA. Reviewers are 
encouraged to read these earlier documents for additional information.

Site Clearance Surveys

    In addition to deep seismic surveys in the Beaufort Sea, Shell also 
plans to conduct site clearance and shallow hazards surveys of 
potential exploratory drilling locations within Shell's lease areas as 
required by MMS regulations. The site clearance surveys are confined to 
very small specific areas within defined OCS blocks. Shell is currently 
in the process of selecting site clearance/shallow hazards and 
geotechnical contractors and vessels for the site clearance/shallow 
hazards surveys, and geotechnical borings. As yet unidentified vessels 
will conduct these surveys contemporaneously with the deep seismic 
survey program. Very small and limited geophysical survey energy 
sources will be employed to measure bathymetry, topography, geo-hazards 
and other seabed characteristics. The actual locations of site 
clearance and shallow hazard surveys have not been definitively set as 
of the date of Shell's application. That information will be supplied 
to NMFS and MMS as it becomes available, but well before the 
commencement of operations. The vessels conducting the site clearance 
and shallow hazard surveys, and geotechnical borings will also operate 
in accordance with the provisions of a Conflict Avoidance Agreement 
(CAA), between the seismic industry and the AEWC and the Whaling 
Captains Associations regarding times and areas in order to avoid any 
possible conflict with the bowhead subsistence whale hunts by the 
Kaktovik and Nuiqsut.
    Offshore site clearance surveys use various geophysical methods and 
tools to acquire graphic records of seafloor and sub-seafloor geologic 
conditions. The data acquired and the type of investigations outlined 
in this document are performed routinely for most exploratory drilling 
and production platforms, submarine pipelines, port facilities, and 
other offshore projects. High-resolution geophysical data such as two- 
dimensional, high-resolution multi-channel seismic, medium penetration 
seismic, subbottom profiler, side scan sonar, multibeam bathymetry, 
magnetometer and possibly piston core soil sampling are typical types 
of data acquired. These data are interpreted to define geologic and 
geotechnical conditions at the site and to assess the potential 
engineering significance of these conditions. The following section 
provides a brief description of those instruments used for site 
clearance that may impact marine mammals. Information on the data 
acquisition methodology planned by Shell can be found in the Shell 
application.

Geophysical Tools for Site Clearance

High-Resolution seismic profiling
    Reflected sound energy, often called acoustic or seismic energy, 
produces graphic images of seafloor and sub-seafloor features. These 
systems transmit the acoustic energy from various sources called 
transducers that are attached to the hull of the vessel or towed 
astern. Part of this energy is reflected from the seafloor and from 
geologic strata below the seafloor. This reflected energy is received 
by the hydrophone or streamer and is recorded to produce seismic 
records or profiles. Seismic profiles often resemble geologic cross-
sections along the course traveled by the survey vessel.
    In most Beaufort Sea site surveys, Shell will operate several high- 
resolution profiling systems simultaneously to obtain detailed records 
of seafloor and near seafloor conditions. A typical survey would 
include data acquisition using a shallow penetration profiler or 
subbottom profiler (1 - 12.0 kHz, typically 3.5 kHz), medium 
penetration system or boomer/sparker/ airgun (400-800 Hz) and a deep 
penetrating hi-res multi-channel seismic system (20-300 Hz) not to be 
confused with the deep seismic used for hydrocarbon exploration. These 
profiling systems complement each other since each system achieves 
different degrees of resolution and depths of sub-seafloor 
penetrations.
Side Scan Sonar
    Unlike seismic profiling systems, which produce a vertical profile 
along the vessel's path, side scan sonar systems provide graphic 
records that show two-dimensional (map) views of seafloor topography 
and of objects on the seafloor. The sonar images provide a swath 
display/record covering an area on the seafloor up to several hundred 
feet on both sides of the survey trackline. The side scan sonar 
transmits very high-frequency acoustic signals (100 - 410 kHz) and 
records the reflected energy from the seafloor. Signals reflected from 
the seafloor are displayed on a continuous record produce by a two-
channel recorder. Reflected signals normally appear as dark areas on 
the record whereas shadows behind objects appear as light or white 
areas. The intensity and distribution of reflections displayed on the 
sonar image depend on the composition and surface texture of the 
reflecting features, on their size, and on their orientation with 
respect to the transducers in the towfish. Line spacing and display 
range are designed to ensure 100 percent coverage of the proposed 
survey area in the prime survey line direction, with additional tie-
lines acquired in an orthogonal direction.
    Side scan sonar data are useful for mapping areas of boulders, rock 
outcrops, and other areas of rough seafloor, and for determining the 
location and trends of seafloor scarps and ice gouges. These data are 
also used to locate shipwrecks, pipelines, and other objects on the 
seafloor.

[[Page 26058]]

Multi-beam Bathymetry
    Multi-beam bathymetric systems are either hull mounted or towed 
astern of the survey vessel. The system transmits acoustic signals 
(200-500 kHz) from multiple projectors propagating to either side of 
the vessel at angles that vary from vertical to near horizontal. The 
locations of the soundings cover a swath whose width may be equal to 
many times the waterdepth. By adjusting the spacing of the survey 
tracklines such that adjacent swaths are overlapping, Shell obtains 
depth information for 100 percent of the bottom in the survey area. The 
time it takes to receive the signals as well as signal intensity, 
position, and other characteristics for echoes received across the 
swath are used to calculate depth of each individual beam transmitted 
across the swath.
    Acoustic systems similar to the ones proposed for use by Shell 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.

Description of Habitat and Marine Mammals Affected by the Activity

    A detailed description of the Beaufort and Chukchi sea ecosystems 
and their associated marine mammals can be found in several documents 
(Corps of Engineers, 1999; NMFS, 1999; Minerals Management Service 
(MMS), 2006, 1996 and 1992) and does not need to be repeated here.

Marine Mammals

    The Beaufort/Chukchi Seas support a diverse assemblage of marine 
mammals, including bowhead whales (Balaena mysticetus), gray whales 
(Eschrichtius robustus), beluga whales (Delphinapterus leucas), killer 
whales (Orcinus orca), harbor porpoise (Phocoena phocoena), ringed 
seals (Phoca hispida), spotted seals (Phoca largha), bearded seals 
(Erignathus barbatus), walrus (Odobenus rosmarus) and polar bears 
(Ursus maritimus). 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 
Shell's application, MMS' PEA, and several other documents (Corps of 
Engineers, 1999; Lentfer, 1988; MMS, 1992, 1996; Hill et al., 1999). 
Information on these species can be found in the NMFS Stock Assessment 
Reports. The Alaska Stock Assessment Report is available at: https://
www.nmfs.noaa.gov/pr/readingrm/MMSARS/sar2003akfinal.pdf. Updated 
species reports are available at: https://www.nmfs.noaa.gov/pr/
readingrm/MMSARS/2005alaskasummarySARs.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 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 Surveys on Marine Mammals

    Shell (2005) states that the only anticipated impacts to marine 
mammals associated with noise propagation from vessel movement, seismic 
airgun operations, and seabed profiling and coring work 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 greater 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. Shell believes that there is no 
evidence that bowheads so exposed have incurred injury to their 
auditory mechanisms. Additionally, Shell 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.
    NMFS notes that 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

[[Page 26059]]

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). 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 Shell seismic 
survey project. 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, 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 
(described later in this document) are 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, as mentioned 
previously, bowhead whales avoid an area many kilometers in radius 
around ongoing seismic operations, precluding any possibility of 
hearing damage.
    When the received levels of noise exceed some behavioral reaction 
threshold, cetaceans will show 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 
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 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 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).
    Results from the 1996-1998 BP and Western Geophysical seismic 
program monitoring in the Beaufort Sea indicate that most 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 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). 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).
    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

[[Page 26060]]

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 
(Pagophilus groenlandicus). 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 Exposed to Seismic Noise

    The methodology used by Shell to estimate incidental take by Level 
B harassment, at sound pressure levels at 160 dB or above, by seismic 
and the numbers of marine mammals that might be affected during the 
proposed seismic acquisition area in the Chukchi and Beaufort seas are 
presented in the application. Subsequent to submission of that 
application, Shell decided to provide more conservative estimates of 
potential marine mammal exposures by using the JASCO model. Therefore, 
Tables 1 and 2 provide exposure calculations for both sets of 
calculations. NMFS proposes to use the more conservative estimates of 
noise exposure to determine impacts to marine mammals.

[[Page 26061]]

[GRAPHIC] [TIFF OMITTED] TN03MY06.000


[[Page 26062]]


[GRAPHIC] [TIFF OMITTED] TN03MY06.001

    The density estimates for the species covered under this IHA are 
based on the estimates developed by LGL (2005). The LGL density 
estimates are based on the original data from Moore et al. (2000) on 
summering bowhead, gray, and beluga

[[Page 26063]]

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, Shell provides estimates of the number of 
potential ``exposures'' to sound levels greater than 160 dB re 1 
microPa (rms) and greater than 170 dB. Shell states that while the 160-
dB criterion is applied for estimating Level B harassment of all 
species of cetaceans and pinnipeds, Shell believes that a 170-dB 
criterion should be considered appropriate for estimating Level B 
harassment of 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 
there is no empirical evidence to indicate that some delphinid species 
do not respond at the lower level (i.e., 160 dB). As a result, NMFS 
proposes to use the 160-dB isopleth to estimate the numbers of marine 
mammals that may be taken by Level B harassment.
    The estimates in Tables 1 and 2 are based on marine mammal 
exposures to 160 dB (and greater) from either approximately 5,556 km 
(3452 mi) of seismic surveys in three distinct areas of the eastern- 
and mid-Beaufort Sea and a similar level of effort in the Chukchi Sea 
or approximately 11,112 km (6905 mi) only in the Chukchi Sea if seismic 
work in the Beaufort Sea is not undertaken. These latter calculations 
are provided in the last column of Table 2.
    There will be no site clearance work performed for the seismic 
activities in the Chukchi Sea, therefore, potential taking estimates 
only include noise disturbance from the use of airguns. It is assumed 
that, during simultaneous operations of those additional sound sources 
and the airgun(s), any marine mammals close enough to be affected by 
the sonars or pinger would already be affected by the airgun(s).

Exposure Calculations for Cetaceans and Pinnipeds

    The 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 (i.e., average and 
maximum), as shown in Tables 1 and 2; (2) the anticipated total line-
kilometers of operations with the three 1,049-in\3\ subarrays (i.e., 
5556 km (3452 mi)); and (3) the cross-track distances within which 
received sound levels are predicted to be between 160 and 180 dB 
(Figure 6-1 and Table 6-3 in the Shell application).
Chukchi Sea
    Shell estimates that the average and maximum numbers of bowhead 
whales that may be exposed to noise levels of 160 dB or greater are 808 
and 3226, respectively. However, according to Shell, the proposed 
seismic activities would occur when bowheads are widely distributed and 
would be expected to occur in very low numbers within the seismic 
activity area. Therefore, based on the 160-dB threshold criterion, the 
number of bowhead whales that may be exposed to sounds at or greater 
than 160 dB re 1 microPa (rms) represent a small percent of the 
estimated population within the Beaufort and Chukchi Seas.
    Gray and beluga whales also have the potential for exposure, 
particularly near Area 3. The average and maximum estimates of the 
number of exposures at or greater than 160 dB are revised as 284 and 
1128 for gray whales, 214 and 851 for beluga whales, 10 for killer 
whales, and 10 and 13 for harbor porpoises.
    While no reliable abundance numbers currently exist for ringed, 
spotted, and bearded seals for the Chukchi Sea, however, the potential 
number of exposures would be a very small fraction of earlier abundance 
estimates as shown in Table 2.
    For both cetaceans and pinnipeds likely to be encountered within 
the Chukchi and Beaufort Sea activity areas, the short-term exposures 
to airgun sounds are not expected to result in any long-term negative 
consequences for the individuals or their populations. Furthermore, the 
estimated number of animals potentially exposed and requested under an 
IHA, will be likely be much less for some species (e.g., bowhead whale) 
because of the period of seismic acquisition, and the survey and 
mitigation plan which contains efforts to further avoid take.
Beaufort Sea
    As indicated in Table 1 in this document, the estimated average and 
maximum numbers for bowhead whales at 160 dB or greater are 395 and 
1579, respectively. However, as stated earlier, proposed activities 
would occur mainly when bowheads are not present in the area or in very 
low numbers.
    Gray and beluga whales also have the potential for exposure, 
particularly near seismic survey area 3. The average and maximum 
estimates of the number of exposures for gray whales are 278 and 1104, 
and 210 and 833 for beluga whales.
    Ringed seals would be the most prevalent marine mammal species 
encountered at each of the three proposed seismic acquisition areas, 
and would account for most of the marine mammals that might be exposed 
to seismic sounds equal to or greater than 160 dB. Potential exposure 
estimates for pinnipeds in the Beaufort Sea are shown in Table 1. 
However, as Moulton and Lawson (2002) indicated that most pinnipeds 
exposed to seismic sounds lower than 170 dB do not visibly react, 
pinnipeds are not likely to react to seismic sounds unless they are 
greater than 170 dB re 1 microPa (rms). As a result, NMFS believes that 
these exposure estimates are very conservative. Spotted and bearded 
seals may be encountered in much small numbers than ringed seals, but 
also have the potential for some minor exposure.
    Finally, if Shell does not conduct seismic survey work in the 
Beaufort Sea in 2006, and implements scenario 2 as mentioned 
previously, Shell estimates that additional sound exposures would occur 
in the Chukchi Sea. These estimates are provided in the last column of 
Table 2.

Potential Impact of the Activity on the Affected Species or Stocks

    According to Shell, the only anticipated impacts to marine mammals 
associated with noise propagation from vessel movement, seismic airgun 
operations and seabed profiling and coring work (in the Beaufort Sea) 
would be the 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 Chukchi Sea seismic 
acquisition activity area are believed 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. 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 less 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. There is no evidence that bowheads so exposed have 
incurred injury to their auditory mechanisms. Additionally, there is no 
conclusive evidence that exposure to sounds exceeding 160 db have 
displaced bowheads from feeding activity (Richardson and Thomson [eds], 
2002). As noted previously, it is highly unlikely that animals will be 
exposed to

[[Page 26064]]

sounds of such intensity and duration as to physically damage their 
auditory mechanisms.
    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.

Potential Impact On Habitat

    Shell 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-June through July and again from mid-October through November). 
The northeastern-most of the recurring feeding areas is in the 
northeastern Chukchi Sea southwest of Barrow. Any effects would be 
temporary and of short duration at any one place. The primary potential 
impacts to marine mammals 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 within 48 hours has been observed 
in cod and plaice 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 
return to the area of disturbance anywhere from 15-30 minutes (McCauley 
et al., 2000) to several days (Engas et al., 1996).
    Available data indicate 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 Shell 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.
    The total footprint of the proposed seismic survey area covers 
approximately 378,000 acres in the Chukchi Sea and 717,000 acres in the 
Beaufort Sea. The effects of the planned seismic activity at each of 
the seismic locations on marine mammal habitats and food resources are 
expected to be negligible, as described. It is estimated that only a 
small portion of the animals utilizing the areas of the proposed 
activities would be temporarily displaced.
    During the period of seismic acquisition in the Chukchi Sea (mid-
June through July, and again in early- to mid-October through November, 
2006), most marine mammals would be dispersed throughout the area. The 
peak of the west- and south-bound bowhead whale migration through the 
Chukchi Sea typically occurs in October, and efforts to reduce 
potential impacts to subsistence hunting 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 numbers of cetaceans and pinnipeds subject to 
displacement are small in relation to abundance estimates for the 
mammals covered under this proposed IHA.
    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 (Shell, 2005). 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) 
suggest 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. As a result, 
Shell believes the proposed activities are not expected to have any 
habitat-related effects that would produce long-term effects to marine 
mammals or their habitat due to the limited extent of the acquisition 
areas and timing of the activities.

Effects of Seismic Noise and Other Activities on the Availability of 
Marine Mammals for Subsistence Uses

    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 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 
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.
    In the Chukchi Sea, Shell seismic work should not have significant 
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. Shell's Chukchi seismic operations will 
not begin until after July 1, 2006 at which time the majority of 
bowheads will have migrated to their summer feeding areas in Canada. In 
the event any bowheads remain in the northeastern Chukchi Sea after 
July 1, they are not normally hunted after this date until the return 
migration occurs

[[Page 26065]]

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 
phase two of the Chukchi 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 matters addressed here 
will be incorporated in the CAA established between Shell 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. As the seismic surveys will be conducted at least 12 
miles (25 km) offshore, impacts to subsistence uses of bowheads are not 
anticipated. However, Shell plans to 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.
    The various pinniped species, including walrus, are all taken by 
subsistence hunters of the Chukchi villages (Barrow, Wainwright, Pt 
Lay, Pt Hope). The planned seismic operations will not adversely affect 
the usual open-water locations of these species and no haul-out areas 
will be encountered (with the possible exception of the polar ice front 
used by walrus, which is under the jurisdiction of the USFWS). However, 
most seismic operations will take place sufficiently distant from 
nearshore traditional beluga, seal, and walrus hunting areas such that 
no unmitigable adverse impacts are anticipated.
    In the Beaufort Sea, there could be an adverse impact on the 
Inupiat bowhead subsistence hunt if the whales were deflected seaward 
(further from shore) in traditional hunting areas. 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. This potential impact will be mitigated 
by application of the procedures established in the CAA between the 
seismic operators and the AEWC and the whaling captains' associations 
of Kaktovik, Nuiqsut and Barrow. The times and locations of seismic and 
other noise producing sources will be curtailed during times of active 
scouting and whaling within the traditional subsistence hunting areas 
of the three potentially affected communities. (Shell, 2005).

Plan of Cooperation

    Regulations at 50 CFR 216.104(a)(12) require IHA applicants for 
activities that take place in Arctic waters to provide a plan of 
cooperation (POC) or information that identifies what measures have 
been taken and/or will be taken to minimize any adverse effects on the 
availability of marine mammals for subsistence uses. Shell's POC notes 
that negotiations were initiated beginning in summer of 2005 with the 
AEWC to create a CAA between Shell and WesternGeco for 2006, and the 
subsistence hunting communities of Barrow, Nuiqsut, and Kaktovik. The 
CAA will cover both the proposed Beaufort Sea seismic program 
(including deep seismic, site clearance, shallow hazard surveys and a 
geotechnical seabed coring program) and the Chukchi Sea deep seismic 
survey. Meetings between Shell and the AEWC began in October, 2005 with 
representatives of the North Slope Borough also present in Fairbanks 
during the annual meeting of the Alaska Federation of Natives. 
Additional meetings were held this spring.
    Shell anticipates signing the CAA sometime this spring. The CAA 
will incorporate all appropriate measures and procedures regarding the 
timing and areas of Shell's planned activities (i.e., times and places 
where seismic operations will be curtailed or moved in order to avoid 
potential conflicts with active subsistence whaling and sealing); 
communications system between operator's vessels and whaling and 
hunting crews (i.e., the communications center will be located in 
Deadhorse with links to Kaktovik, Nuiqsut, Cross Island, and Barrow); 
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 2006 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 is anticipated 
that a final draft of the 2006 CAA for the Beaufort and Chukchi Seas 
will be available for consideration and review by NMFS and the MMS by 
late spring.

Proposed Mitigation Measures

    Shell has proposed five main mitigation measures: (1) The timing 
and locations for active seismic acquisition work will be scheduled to 
curtail operations when whaling captains inform the operator that they 
are scouting or hunting within traditional hunting areas; (2) the 
configuration of airguns in a manner that directs energy primarily down 
to the seabed thus decreasing the range of horizontal spreading of 
seismic noise; (3) the use of a seismic energy source which is as small 
as possible while still accomplishing the geophysical objectives; (4) 
the use of ramp-up and soft start methods of initiating seismic 
operations which is intended to alert any marine mammals either within 
or approaching an operating airgun array so that they may swim away 
from the source; and (5) the curtailment of active seismic work when 
the marine mammal observers (MMOs) visually sight (from shipboard or 
aerially) the presence of marine mammals within identified ensonified 
zones. Details of the proposed mitigation measures follow:
    Seasonal Restrictions: Shell has proposed to take all practicable 
measures to complete seismic operations as early as possible and to 
vacate areas within close proximity of subsistence bowhead hunting 
areas during periods of hunting activity. During periods of hunting 
activity, seismic operations will be moved to areas remote from hunting 
operations or ceased for a period. From August 15 until the end of the 
bowhead hunting season (or until the end of seismic operations in the 
Beaufort Sea) special monitoring and mitigation/mitigation measures 
will be adopted (i.e., aerial surveys). Given the potential for 
diversion offshore, re-initiation of seismic operations within 
identified hunting areas will proceed only after the affected 
village(s) has acquired at least two whales or ceased hunting 
activities and only with close coordination with representatives of the 
whaling captains. All reasonable efforts will be made to avoid 
disruption of the hunt or deflection of migrating bowheads in hunting 
areas.
    Aerial Surveys: Shell proposes to conduct aerial surveys of the 
Beaufort Sea regional distribution and abundance of marine mammals with 
special attention to bowhead whales in 2006 prior to the initiation of 
the seismic survey starts and periodically during and after the survey. 
The objectives of the Beaufort Sea aerial surveys are to:
    (a) Provide real-time or near real-time information that can be 
used (if appropriate) to alter the survey's starting point and survey 
line sequence based on the actual distribution of whales in the

[[Page 26066]]

area immediately prior to and during surveys (see below),
    (b) Document the numbers of whales in the general area and, at 
least theoretically, exposed to noise from seismic survey and their 
responses to the surveys (if detectable), and
    (c) Conduct aerial surveys only when they can be carried out in a 
safe manner and during periods of good visibility where there is 
sufficient probability of detecting bowhead whales and other marine 
mammals.
    Beginning at least 3 days prior to the beginning of seismic surveys 
in the Beaufort Sea, aerial surveys will be conducted on a daily basis, 
when practicable given weather and visibility conditions.
    Aerial surveys conducted during the bowhead whaling season will be 
coordinated with whaling efforts, such that airplanes operating in 
close proximity to whalers can take action, e.g. flying at higher 
altitudes, to reduce the potential to impact the hunt.
    Generally, the flight plan and coverage of the aerial survey will 
be conducted following established standards and methodologies, as 
described above, with particular reference to MMS Bowhead Whale Aerial 
Survey Program (BWASP) procedures. Specific details of the flight 
pattern and coverage will be fully developed in an aerial flight 
operations plan but will be subject to operation changes as needed to 
provide effective coverage during field operations.
    Airgun Arrays: For the proposed seismic survey, Shell proposes to:
    (a) Configure the airgun array to maximize the proportion of the 
energy that is directed downward and to minimize horizontal sound 
propagation. In particular, closely spaced airguns whose overall 
radiation pattern is nearly omni-directional will be avoided. The size 
of the airgun arrays, as measured by the source level, will not be any 
larger than required to meet the technical objectives for the seismic 
survey.
    (b) Utilize pre-initiation modeling, based upon anticipated sound 
propagation characteristics of the array, to establish anticipated 
impact zones of 180 dB and 190 dB.
    (c) Conduct field sound propagation assessments at the initiation 
of the field season and 180 dB and 190 dB zones adjusted accordingly.
    Ramp-up (soft-start): For the proposed seismic survey, Shell 
proposes to implement the following 'soft start' procedures:
    (a) The seismic operator will ramp-up airguns slowly over a period 
of 20 minutes each time shooting begins or whenever the, shut-down 
period has been greater than 10 minutes. 'Soft starts' will follow 
every interruption of the airgun array firing that is greater than 10 
minutes, most importantly if the survey is discontinued until marine 
mammals leave the safety zone. The seismic operator and MMOs will 
maintain records of the times when ramp-ups start, and when the airgun 
array reaches full power.
    (b) During periods of turn around and transit between seismic 
transects, one airgun will remain operational. Through use of this 
approach, seismic operations can resume upon entry to a new transect 
without full ramp up. While it is routine to ramp up from a single gun 
firing to full array operation, operation of a single gun allows 
starting during poor visibility and ramp up without a period of static 
visual observation.
    (c) If shut down occurs, ramp-up will begin only following a 
minimum of a 30-min period of observation of the prescribed safety zone 
to assure that no marine mammals are present. However, if the MMOs were 
on-duty prior to the sh