Small Takes of Marine Mammals Incidental to Specified Activities; Seismic Survey in the Beaufort Sea, Alaska, Summer 2008, 34254-34268 [E8-13650]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 73, Number 117 (Tuesday, June 17, 2008)]
[Notices]
[Pages 34254-34268]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E8-13650]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XI41


Small Takes of Marine Mammals Incidental to Specified Activities; 
Seismic Survey in the Beaufort Sea, Alaska, Summer 2008

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

ACTION: Notice; proposed incidental take authorization; request for 
comments.

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SUMMARY: NMFS has received an application from PGS Onshore, Inc. (PGS) 
for an Incidental Harassment Authorization (IHA) to take marine mammals 
incidental to an exploratory three-dimensional (3D) marine seismic 
survey in the Beaufort Sea, Alaska, utilizing an ocean bottom cable/

[[Page 34255]]

transition zone (OBC/TZ) technique in summer 2008. Pursuant to the 
Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its 
proposal to issue an IHA to PGS to incidentally take, by harassment, 
small numbers of several species of marine mammals between July and 
September, 2008, during the aforementioned activity.

DATES: Comments and information must be received no later than July 17, 
2008.

ADDRESSES: 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 email comments is PR1.0648XI41@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 the address specified 
above, telephoning the contact listed below (FOR FURTHER INFORMATION 
CONTACT), or visiting the Internet at: https://www.nmfs.noaa.gov/pr/
permits/incidental.htm#applications.
    Documents cited in this notice may be viewed, by appointment, 
during regular business hours, at the aforementioned address.
    A copy of the 2006 Minerals Management Service's (MMS) Final 
Programmatic Environmental Assessment (PEA) and/or the NMFS/MMS Draft 
Programmatic Environmental Impact Statement (DPEIS) are available on 
the Internet at: https://www.mms.gov/alaska/.

FOR FURTHER INFORMATION CONTACT: Candace Nachman, Office of Protected 
Resources, NMFS, (301) 713-2289 or Brad Smith, NMFS, Alaska Region, 
(907) 271-3023.

SUPPLEMENTARY INFORMATION:

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce to allow, upon request, the 
incidental, but not intentional, taking of small numbers of marine 
mammals by U.S. citizens who engage in a specified activity (other than 
commercial fishing) within a specified geographical region if certain 
findings are made and either regulations are issued or, if the taking 
is limited to harassment, a notice of a proposed authorization is 
provided to the public for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s), will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for subsistence uses (where 
relevant), and if the permissible methods of taking and requirements 
pertaining to the mitigation, monitoring and reporting of such takings 
are set forth. NMFS has defined ``negligible impact'' in 50 CFR 216.103 
as ``...an impact resulting from the specified activity that cannot be 
reasonably expected to, and is not reasonably likely to, adversely 
affect the species or stock through effects on annual rates of 
recruitment or survival.''
    Section 101(a)(5)(D) of the MMPA established an expedited process 
by which citizens of the United States can apply for an authorization 
to incidentally take small numbers of marine mammals by harassment. 
Except with respect to certain activities not pertinent here, the MMPA 
defines ``harassment'' as:

    any act of pursuit, torment, or annoyance which (i) has the 
potential to injure a marine mammal or marine mammal stock in the 
wild [Level A harassment]; or (ii) has the potential to disturb a 
marine mammal or marine mammal stock in the wild by causing 
disruption of behavioral patterns, including, but not limited to, 
migration, breathing, nursing, breeding, feeding, or sheltering 
[Level B harassment].

    Section 101(a)(5)(D) establishes a 45-day time limit for NMFS 
review of an application followed by a 30-day public notice and comment 
period on any proposed authorizations for the incidental harassment of 
marine mammals. Within 45 days of the close of the comment period, NMFS 
must either issue or deny the authorization.

Summary of Request

    On May 9, 2008, NMFS received an application from PGS for the 
taking, by Level B harassment only, of small numbers of several species 
of marine mammals incidental to conducting an exploratory 3D marine 
seismic survey in the Alaskan Beaufort Sea, utilizing an OBC/TZ 
technique. PGS has been contracted by ENI Petroleum (ENI) to conduct 
the seismic survey. The proposed survey is scheduled to occur from July 
to mid-September 2008. Because the proposed survey is weather and ice 
dependent, the exact dates of the survey cannot be determined at this 
time. However, the proposed survey would begin as soon as ice and 
weather conditions allow, possibly as soon as July 1. The survey is 
expected to last for an estimated 75 days of data acquisition, 
excluding weather days.
    The proposed survey location is in the Nikaitchuq Lease Block (see 
Figure 1 of PGS' application), north of Oliktok Point and covering 
Thetis, Spy, and Leavitt Islands, and would extend to the 5-km (3-mi) 
state/Federal water boundary line and would not go into Federal waters. 
The water depth in this area ranges from 0-15 m (0-49 ft), and a third 
of the project waters are shallower than 3 m (10 ft). The total area 
covered by source or receiver lines is 304.6 km\2\ (117.6 mi\2\); since 
the islands comprise approximately 1.7 km\2\ (0.7 mi\2\) of this, the 
total marine area is 303 km\2\ (117 mi\2\).
    The work would be divided into two parts. Data acquisition (use of 
airguns) outside the barrier islands (Thetis, Spy, and Leavitt Islands) 
would be performed first and would be completed by August 5. This 
portion of the work would begin in the east and move toward the west. 
Data acquisition inside the barrier islands would then be conducted and 
would be completed by September 15. This portion of the work would also 
move from east to west. No data acquisition (use of airguns) would be 
conducted outside the barrier islands after August 5.

Description of Activity

    The OBC/TZ survey involves deploying cables from small boats, 
called DIB boats, to the ocean bottom, forming a pattern consisting of 
three parallel receiver line cables, each a maximum of 17.3 km (10.7 
mi) long and spaced approximately 200 m (656 ft) apart. Hydrophones and 
geophones attached to the cables are used to detect seismic energy 
reflected back from rock strata below the ocean bottom. The energy is 
generated from a submerged acoustic source, called a seismic airgun 
array, that releases compressed air into the water, creating an 
acoustic energy pulse directed downward toward the seabed. PGS proposes 
using two shallow water source vessels for this survey. The source 
vessels will be used sequentially: one vessel will be active while the 
other travels to its next position. Both source vessels, M/V Wiley 
Gunner and M/V Little Joe, will each be equipped with identical airgun 
arrays with total air discharge volume of 880 in\3\. The source has a 
peak to peak amplitude equal to 31.4 bar-meters, giving a source output 
of approximately 250 dB. These airgun arrays are expected to operate at 
a depth of between 0.91 m and 2.29 m (3 ft and 7.5 ft). Data 
acquisition would also require the following instrumentation 
(instrumentation specifications are included in Appendix A of PGS' 
application): seismic recording equipment; line equipment; transducers; 
energy source output; bathymetry; and positioning survey equipment.

[[Page 34256]]

Vessel Descriptions

    The marine crew would be configured with the following vessels 
(vessel specifications are included in Appendix A of PGS' application). 
Vessel usage is subject to availability; however, vessels of similar 
dimensions will be used if those listed below are unavailable.
     Two source vessels, the M/V Wiley Gunner and the M/V 
Little Joe, which are both 13 m (44 ft) long, 5.8 m (19 ft) wide, and 
3.5 m (11.5 ft) tall with a weight of 18 metric tons (20 tons) loaded 
and a draft of 0.69 m (2.2 ft) with the engines down. These boats are 
able to maneuver in waters less than 1.2 m (4 ft) deep.
     The recording vessel, M/V William Bradley, is a self-
propelled barge and has hydraulic gravity spuds that can be lowered in 
water up to 6 m (20 ft) deep. It would be fitted with a Sercel 408 
recording system. The William Bradley is 45.7 m (150 ft) long and 11 m 
(36.1 ft) wide with a draft of 1.23 m (4 ft).
     Up to seven shallow-water cable boats (DIB boats) would be 
available for the survey. The DIB boats are 12.5 m (41 ft) long and 4.3 
m (14 ft) wide and have 0.76 m (2.5 ft) draft. The boats are powered by 
two, 200-horsepower (HP) diesel Volvo Penta engines. The dry weight of 
each boat is 4.5 metric tons (5 tons) with a working load of 7.7 metric 
tons (8.5 tons).
     The supply boat M/V Katmai Spirit would be used for crew 
support and supplying marine vessels during the job. The Katmai Spirit 
has dimensions of 12 m (40 ft) long, 5.5 m (18 ft) wide, and 0.6 m (2 
ft) draft.
     The Project Manager/Client boat would be available for use 
by the Project Manager, the client, or other personnel as needed to 
perform their tasks. The boat may also be used for crew support and 
supplying marine vessels as required. The Project Manager/Client boat 
has dimensions of 7.3 m (24 ft) long, 2.4 m (8 ft) wide, and 0.45 m 
(1.5 ft) draft. The boat is powered by a 90 HP engine.
     The Mechanic's boat would be used to support maintenance 
and mechanical support for marine vessels used during the project. The 
Mechanic's boat has dimensions of 7.9 m (26 ft) long, 2.4 m (8 ft) 
wide, and 0.45 m (1.5 ft) draft. The boat is powered by twin 90 HP 
engines.

Seismic Recording Equipment

    The seismic recording system scheduled to be housed on the William 
Bradley during the proposed 3D marine seismic survey is a Sercel 408. 
The system would record data using a tape emulator drive hard drive 
imbedded into the recorder so that verified IBM 3590 archive tapes can 
be created at the quality control processing laboratory. Digital 
records would be formatted in SEG D configuration and traced at three 
lines of 156 per record for every 2-ms periods. The digital filters 
would be linear or minimum phase, and the anti-alias filters would be 
high-cut 0.8 Field Nyquist Stop Band Attenuation greater than 120 dB. 
Record length would be 6 s versus a shot point distance of 34 m (111.5 
ft). This Sercel system would be capable of an inter-record delay of 
equal to or less than 2 s of overhead. The plotter that would also be 
housed on the William Bradley would be a Veritas V-12.

Line Equipment

    PGS would have a 2400 Sercel FDU Operative Remote Acquisition Units 
available. The following equipment would also be available: 125 Sercel 
line acquisition unit line repeaters/powers; 12 Sercel line acquisition 
unit crossing line interface; 20 x-line cables; and 1,200 telemetry 
cables of 67 m (220 ft) each and 1,200 mini cables of 1 m (3.3 ft) 
each.

Transducers

    The transducers used during the proposed seismic survey in the 
Beaufort Sea would be GeoSpace GS-PV1 sensors. The GS30CT geophone has 
a sensitivity of 2.55 volts (V) per inch per second  2 
percent. The pressure phone has a sensitivity of 6.76 V/bar  1.5 dB. The hydrophone crystals are configured for acceleration 
cancellation.

Energy Source Output

    PGS would use an airgun energy source for the proposed data 
acquisition. A minimum of a 10-airgun array is expected to be used as a 
single output source. The operating source depth for the guns is a 
maximum of 2.5 m (8.2 ft). Source centers separation will be from 1-1.5 
m (3.3-4.9 ft), and the shot point distance is 34 m (110 ft). The 
single source volume is 880 in\3\. Although PGS is proposing to use 
only a 10-airgun array for acquisition, a 12 airgun array would be 
placed on each vessel. This would provide two spare airguns at all 
times. The source layout will be 8 m (26 ft) wide by 6 m (20 ft) long. 
At a depth of 2.5 m (8.2 ft), the point to point output pressure is 
plus or minus 22 bar meters, giving a signal/bubble ratio of 10:1. The 
array is designed to direct sound pressure downwards, as shown in 
Figure 2 of PGS' application.
    The power is provided by either a 78 cubic feet per minute (CFM) or 
150 CFM diesel air compressor. The air pressure can deliver between 
1,750 pounds per square inch (psi) to 1,900 psi. This system will 
require a 12-s to 15-s recycle time. The energy source synchronizing 
system is a Digital Real Time Long Shot Source Controller.

Bathymetry

    Bathymetric equipment would be located on each of the source 
vessels and the shallow-water cable boats. Bathymetric data would be 
recorded simultaneously with the seismic data acquisition, by employing 
Interspace Tech DX 150 (or equivalent) instruments, which can operate 
in water up to 120 m (400 ft) deep. This equipment has an operating 
frequency of 200 kHz and a sound source of 100 dB re 1 [mu]Pa. The 
digitizer and logger system would be a National Marine Electronic 
Association standard output to Horizon. PGS would use a Gator INM 
system and a Gator INS system as source firing controllers. For 
measures of depth, temperature, and salinity, a Valeport TS Dip Meter 
would be used.

Positioning Survey Equipment

    To conduct the proposed 3D seismic survey in the Beaufort Sea, PGS 
would employ a Novatel system and a global positioning system (GPS) 
mobile receiver with 8 to 12 channels of dual frequency. For the 
Novatel system, there would be three onshore reference stations and 
four valid satellites. As a second main system, PGS has available a 
Trimble 4700 system and a GPS Mobile Receiver, also with 8 to 12 
channels of dual frequency. For the Trimble 4700, there would be two 
onshore reference stations. PGS will also have 700 active Sonardyne 
Acoustic transponders available for in-water positioning.

Marine Mammals Affected by the Activity

    The Beaufort Sea supports a diverse assemblage of marine mammals, 
including bowhead, gray, beluga, killer, minke, fin, humpback, and 
North Pacific right whales, harbor porpoises, ringed, spotted, bearded, 
and ribbon seals, polar bears, and walruses. 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. Within the 
project activity areas, only the polar bear is known to occur in 
significant numbers, and a separate Letter of Authorization request 
will be submitted by PGS to USFWS for this species.
    A total of three cetacean species and three pinniped species are 
known to occur or may occur in the Beaufort Sea in or near the proposed 
project area (see

[[Page 34257]]

Table 3.0-1 in PGS' application for information on habitat and 
estimated abundance). Of these species, only the bowhead whale is 
listed as endangered under the Endangered Species Act (ESA). The killer 
whale, harbor porpoise, minke whale, fin whale, North Pacific right 
whale, humpback whale, and ribbon seal could occur in the Beaufort Sea, 
but each of these species is rare or extralimital and unlikely to be 
encountered in the proposed seismic survey area.
    The marine mammal species expected to be encountered most 
frequently throughout the seismic survey in the project area is the 
ringed seal. The bearded and spotted seal can also be observed but to a 
far lesser extent than the ringed seal. Presence of beluga, bowhead, 
and gray whales in the shallow water environment within the barrier 
islands is possible but expected to be very limited as this is not 
their typical habitat. Descriptions of the biology, distribution, and 
population status of the marine mammal species under NMFS' jurisdiction 
can be found in PGS' application, the 2007 NMFS/MMS DPEIS on Arctic 
Seismic Surveys, and the NMFS Stock Assessment Reports (SARS). The 
Alaska SAR is available at: https://www.nmfs.noaa.gov/pr/pdfs/sars/
ak2007.pdf. Please refer to those documents for information on these 
species.

Potential Effects of Airgun Sounds on Marine Mammals

    The effects of sounds from airguns might include one or more of the 
following: tolerance, masking of natural sounds, behavioral 
disturbance, and temporary or permanent hearing impairment or non-
auditory effects (Richardson et al., 1995). As outlined in previous 
NMFS documents, the effects of noise on marine mammals are highly 
variable, and can be categorized as follows (based on Richardson et 
al., 1995):
    (1) 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.

Tolerance

    Numerous studies have shown that pulsed sounds from airguns are 
often readily detectable in the water at distances of many kilometers. 
Numerous studies have shown that marine mammals at distances more than 
a few kilometers from operating seismic vessels often show no apparent 
response. That is often true even in cases when the pulsed sounds must 
be readily audible to the animals based on measured received levels and 
the hearing sensitivity of that mammal group. Although various baleen 
whales, toothed whales, and (less frequently) pinnipeds have been shown 
to react behaviorally to airgun pulses under some conditions, at other 
times, mammals of all three types have shown no overt reactions. In 
general, pinnipeds and small odontocetes seem to be more tolerant of 
exposure to airgun pulses than baleen whales.

Masking

    Masking effects of pulsed sounds (even from large arrays of 
airguns) on marine mammal calls and other natural sounds are expected 
to be limited, although there are very few specific data of relevance. 
Some whales are known to continue calling in the presence of seismic 
pulses. Their calls can be heard between the seismic pulses (e.g., 
Richardson et al., 1986; McDonald et al., 1995; Greene et al., 1999; 
Nieukirk et al., 2004). Although there has been one report that sperm 
whales cease calling when exposed to pulses from a very distant seismic 
ship (Bowles et al., 1994), a more recent study reports that sperm 
whales off northern Norway continued calling in the presence of seismic 
pulses (Madsen et al., 2002). That has also been shown during recent 
work in the Gulf of Mexico (Tyack et al., 2003; Smultea et al., 2004). 
Masking effects of seismic pulses are expected to be negligible in the 
case of the smaller odontocete cetaceans, given the intermittent nature 
of seismic pulses. Dolphins and porpoises commonly are heard calling 
while airguns are operating (e.g., Gordon et al., 2004; Smultea et al., 
2004; Holst et al., 2005a; 2005b). Also, the sounds important to small 
odontocetes are predominantly at much higher frequencies than are 
airgun sounds.

Disturbance Reactions

    Disturbance includes a variety of effects, including subtle changes 
in behavior, more conspicuous changes in activities, and displacement. 
Reactions to sound, if any, depend on species, state of maturity, 
experience, current activity, reproductive state, time of day, and many 
other factors. If a marine mammal does react briefly to an underwater 
sound by changing its behavior or moving a small distance, the impacts 
of the change are unlikely to be significant to the individual, let 
alone the stock or the species as a whole. However, if a sound source 
displaces marine mammals from an important feeding or breeding area for 
a prolonged period, impacts on the animals could be significant. Given 
the many uncertainties in predicting the quantity and types of impacts 
of noise on marine mammals, it is common practice to estimate how many 
mammals were present within a particular distance of industrial 
activities or exposed to a particular level of industrial sound. That 
likely overestimates the numbers of marine mammals that are affected in 
some biologically-important manner.

[[Page 34258]]

    The following species summaries are provided to facilitate 
understanding of our knowledge of impulsive noise impacts on the 
principal marine mammal species that are expected to be affected. The 
impacts on Beaufort Sea cetaceans and pinnipeds are likely to be short-
term and transitory.
    Bowhead Whales--Bowhead whales will likely show some behavioral 
changes during airgun activity, but depending on distance from the 
noise source, overall displacement should be minimal. Bowhead whales in 
the Beaufort Sea were observed remaining in a location where they were 
exposed to seismic, dredging, and drilling sounds. Their social and 
feeding behavior appeared normal as industry-related noises occurred 
(Richardson et al., 1987). When observed over multiple years, bowhead 
whales in the same area also did not appear to avoid seismic locations. 
MMS did not find a statistical difference in the change of direction 
for bowhead whales traveling during seismic activity when analyzing 
fall migration data from 1996 to 1998 (MMS, 2005). Bowhead and gray 
whales have not appeared bothered when seismic pulses between 160 dB 
and 170 dB re 1 [mu]Pa were fired from a seismic vessel within a few km 
of their locality, but tended to avoid the area when levels exceeded 
170 dB (Richardson et al., 1997).
    Common behavioral responses of marine mammals include displacement, 
startle, attraction to sound, altered communication sounds, 
discontinued feeding, disruption to social behaviors, temporary or 
permanent habitat abandonment, panic, flight, stampede, and in worse 
cases stranding, and sometimes death (Nowacek et al., 2007; Southall et 
al., 2007; Gordon et al., 2004). Behavior ranges from temporary to 
severe, and the effects can influence foraging, reproduction, or 
survival. Response level is based on how habituated or sensitive the 
individual mammal is and whether or not previous interactions with 
sound was positive, negative, or neutral (Southall et al., 2007). The 
common behavioral patterns seen in bowhead whales when seismic 
operations were operated nearby include displacement, avoidance, and 
altered respiration (Richardson et al.,1999; Ljungland et al., 1988). 
Whales may also display varied reactions based on the time of year and 
activity. Bowhead whales migrating in the fall exhibited avoidance at 
distances up to 20 km (12 mi) or more, while bowheads feeding during 
summer displayed more subtle reactions and did not show a strong 
avoidance at distances past 6 km (3.7 mi) from active airguns (Miller 
et al., 2005).
    It is unclear exactly what causes displacement, but whales have 
tended to show shorter surface and dive times, fewer blows per 
surfacing, and longer blow intervals when noise levels were at or above 
152 dB and showed avoidance of seismic operations within a 20-km (12-
mi) radius (Ljungbald, 1988; Richardson, 1999). Bowhead whales may also 
flee from or show total avoidance of vessels if they are too close. 
Bowhead whales showed total avoidance at distances of 1.3 km, 7.2 km, 
3.5 km, and 2.9 km (0.8 mi, 4.5 mi, 2.2 mi, and 1.8 mi) when sound 
levels were 152 dB, 165 dB, 178 dB, and 165 dB, respectively (Ljungbald 
et al., 1988). Based upon McCauley et al. (2000) bowhead whales exhibit 
a behavioral change at 120 dB when migrating. However, other low-
frequency cetaceans, including bowhead whales, exhibit behavioral 
changes at 140 dB to 160 dB when not migrating, and sometimes higher 
levels (Miller et al., 2005).
    Beluga Whales--Seismic activity is expected to cause temporary 
displacement of beluga whales, but the impact is not expected to be 
significant. Belugas have been shown to have greater displacement in 
response to a moving source (e.g., airgun activity on a moving vessel) 
and less displacement or behavioral change in response to a stationary 
source. The presence of belugas has been documented within the 
ensonified zones of industrial sites near platforms and stationary 
dredges, and the belugas did not seem to be disturbed by the activity 
(Richardson et al., 1995). When drilling sounds were played to belugas 
in industry-free areas, the belugas only showed a behavioral reaction 
when received levels were high. For example, beluga whales have been 
observed to show only an initial scare when drilling noises were played 
with a received level greater than or equal to 153 dB re 1 [mu]Pa. 
Richardson (1997) suggested that the effect could be a result of 
belugas having less sensitivity to low-frequency sounds. Other reports 
suggested that belugas will remain far away from seismic vessels 
(Miller et al., 2005). A study in the Beaufort Sea observed low numbers 
of belugas within 10 km to 20 km (6 mi to 12 mi) of seismic vessels 
(noted in LGL, 2006).
    Gray Whales--Gray whales in the immediate area of seismic activity 
will likely show some behavioral changes. The changes in behavior, 
however, depend upon distance from the seismic source and are expected 
to be minimal. In a study including gray whales, behavioral responses 
were observed when the whales were subjected to seismic sounds between 
160 and 170 dB re 1 [mu]Pa. Studies in the Bering Sea by Malme et al. 
(1986, 1988) showed the responses of gray whales to seismic sound 
pulses from a 100 in\3\ airgun array. Fifty percent of feeding whales 
stopped feeding when exposed to sound levels of 173 dB re 1 [mu]Pa on 
average, and 10 percent stopped feeding at a received sound level of 
163 dB re 1 [mu]Pa. One whale study found indications of behavioral 
changes such as increased swim speed and shorter blow periods for 
seismic activities at a distance of up to 30 km (Wursig et al., 1999). 
However, when conducting shore-based counts Johnson (2007) did not 
mention any change in behavior and found no significance between 
abundance and seismic activity. Also, given the infrequent occurrence 
of gray whales in the Beaufort Sea east of Point Barrow, recent marine 
mammal observer (MMO) information from the Beaufort Sea indicating 
that, at least for bowhead whales, sound pressure levels of 160 dB or 
less did not result in abandonment of feeding areas, and the 
incorporation of mitigation and monitoring measures, including the use 
of MMOs and avoidance of concentrated areas of feeding whales, the 
number of animals exposed to sound levels that could cause disturbance 
of feeding or other behaviors should be greatly reduced.
    Data on short-term reactions of cetaceans to impulsive noises do 
not necessarily provide information about long-term effects. It is not 
known whether impulsive noises affect reproductive rate or distribution 
and habitat use in subsequent days or years. Gray whales continued to 
migrate annually along the west coast of North America despite 
intermittent seismic exploration (and much ship traffic) in that area 
for decades (Malme et al., 1984; Richardson et al., 1995; Angliss and 
Outlaw, 2005).
    Ringed Seals--Ringed seals are expected to have only short-term and 
temporary displacement as a result of the proposed PGS project 
activities. Seals should not be exposed to source levels higher than 
190 dB re 1 [mu]Pa due to the potential for hearing damage. Though 
ringed seals have density and estimated take higher than other marine 
mammals in the project area, ringed seals exposed to sound sources as 
high as 200 dB, displayed only brief orientation and minor behavioral 
modifications, and only momentarily left young (Moulton et al., 2005; 
Southall, 2007; Blackwell, 2004). Any behavioral reactions to 
activities should only be temporary and not disrupt

[[Page 34259]]

reproductive activities. When industrial-related sounds propagated 1-3 
km (0.6-1.9 mi) within ringed seal locations, normal behavior such as 
maintaining active breathing holes and lairs continued, and observed 
breeding females appeared not to be bothered (Moulton et al., 2005).
    In 1998, a total of 252 ringed seals were counted in the project 
area over a period of 1,331 hours, contributing to 98.5 percent of the 
total pinniped population during this time. Richardson (1999) found 
sounds produced from both a 16 - 1,500 in\3\ sleeve gun array and 
another 8 - 560 in\3\ sleeve gun array affected distribution and 
behavior only when seals were within a few hundred meters of the array, 
and ringed seals remained in the project area during operations. During 
seismic activities, whales also remained at a mean radial distance of 
223 m (731 ft) during seismic operations and 116 m (381 ft) when 
seismic operations did not occur (Richardson, 1999). Over time, ringed 
seals may also show less displacement and fewer behavioral changes. In 
one study, ringed seals remained distant from activities during the 
first season of seismic activities, but during the second season, were 
observed at close proximity of the marine vessel. No observable 
behavioral changes were accounted for with received levels ranging 
between 170 and 200 dB (Miller et al., 2005).
    Spotted Seals--The total number of spotted seals in Alaska is 
assumed to be tens of thousands, and their range sometimes includes the 
Beaufort Sea (MMS, 1996; Rugh et al., 1997). Any impacts on spotted 
seal populations should also be minimal as high numbers of spotted 
seals should not occur in the project area. From July-September 1996, 
Harris et al. (2001) counted a total of 422 seals in the Beaufort Sea. 
Of the seals counted, only 0.9 percent (n = 4) were spotted seals. 
Spotted seal reactions to seismic activities are typically minimal, and 
spotted seals have demonstrated little or no reaction to scare devices 
even when linked to areas for feeding or reproduction (Harris et al., 
2001).
    Bearded Seals--In a study during summer 1996, Harris et al. (2001) 
found bearded seals were 7.3 percent (n = 31) of the total number of 
seals counted. Though bearded seals are bottom feeders and are usually 
found in water depths less than 200 m (656 ft), if the rarity of an 
encounter should occur, bearded seals, like other pinnipeds, should 
demonstrate only minimal displacement and behavioral reaction. Bearded 
seals did not show reactions to 1,450 in\3\ to 2,250 in\3\ airguns when 
received levels averaged in the range of 170-200 dB (Richardson, 1999).

Hearing Impairment

    When conducting the proposed seismic activities, TTS or permanent 
threshold shift (PTS) is not expected to occur in marine mammals. When 
marine mammals located within a vulnerable range (> 180 dB re 1 [mu]Pa 
for cetaceans, or > 190 dB re 1 [mu]Pa for pinnipeds) are impacted by 
impulsive noises, the noises can lead to TTS or PTS. When TTS occurs, 
the result is reversible: hearing in exposed mammals is temporarily 
affected. TTS may result in mammals failing to locate predators or prey 
and the inability to communicate effectively with other individuals of 
the same species. When the threshold does not return to the original 
threshold levels, the damage is classified as PTS. It is unknown what 
level of sound will cause PTS in marine mammals, but it is reasoned to 
occur at a much greater level than that caused by TTS (Southall et al., 
2007).
    TTS and PTS in given species depends upon the frequency sensitivity 
of that species. Bowhead and gray whales operate at a low frequency, 
killer whale and beluga at mid frequency, and the harbor porpoise at 
high frequency (Southall, 2005). Finneran (2002) estimated that sound 
levels greater than 192 dB re 1 [mu]Pa will lead to TTS in most 
cetaceans. There are no data identifying the level of sound intensity 
that causes TTS in baleen whales, but because most baleen whales show 
avoidance at certain sound intensities, risk of TTS should be avoided 
(MMS, 2006; Southall, 2007). Under prolonged exposure, pinnipeds have 
been shown to exhibit TTS. Kastak et al. (1999) investigated the 
effects of noise on two California sea lions, one northern elephant 
seal, and one harbor seal. Kastak et al. (1999) subjected each pinniped 
to a noise source (100 to 2,000 Hz) for 20 to 22 min. Each pinniped 
showed a threshold shift averaging 4.8 dB (harbor seal), 4.9 dB (sea 
lion), and 4.6 dB (northern elephant seal) until the hearing threshold 
returned to pre-exposure values (under a 12-hour period). PGS 
mitigation measures, such as monitoring by MMOs within the safety zone 
and ramp-up prior to seismic operations, should prevent marine mammals 
from sound exposure that causes TTS and PTS. Currently NMFS considers 
190 dB re 1 [mu]Pa received level as the onset of TTS for pinnipeds.

Potential Effects of Bathymetric Equipment on Marine Mammals

    The bathymetric equipment used to determine depth will operate at a 
frequency of 200 kHz and sound source of 100 dB. At a frequency of this 
caliber, any overlap with the functional marine mammal hearing groups 
and the estimated auditory bandwidth at which they are suspected to 
hear will be avoided (Southall et al., 2007). Of the marine mammals in 
the project area, bowhead whales are considered low-frequency mammals, 
and their estimated bandwidth occurs between 7 and 22 kHz (Southall et 
al., 2007). Though no direct measurements have been tested directly on 
the low-frequency cetaceans, such as bowhead whales, hearing 
sensitivity was determined by observable levels of response to sound 
levels played at various frequencies, including vocalization 
frequencies (Southall et al., 2007; Richardson et al., 1995).
    The only mid-frequency marine mammal expected within the project 
area is the beluga whale. Estimated auditory bandwidth for belugas 
occurs between 150 Hz and 160 kHz (Southall et al., 2007). Beluga 
hearing is functional and occurs over a low to very high range. Belugas 
also typically detect signals only within their frequency but have 
specialized echolocation features that cater to communication and 
tracking prey (Southall et al., 2007).
    No high-frequency cetaceans are expected within the project area; 
however, pinnipeds, such as the ringed, spotted, and bearded seals will 
be present. Pinnipeds lack the specialized biosonar systems common to 
beluga whales. Pinnipeds also communicate in water and air but are 
expected to be more sensitive to noises in water. Pinnipeds are 
estimated to have an auditory bandwidth range at 75 Hz to 75 kHz in 
water and 75 Hz to 30 kHz in air (Southall et al., 2007). Based on 
information that is available, the bathymetric equipment proposed to be 
used within the project area will not overlap with the hearing range of 
marine mammals. Therefore, the likelihood of impacts, if any, are 
expected to be quite low.

Estimated Take of Marine Mammals by Incidental Harassment

    The anticipated harassments from the activities described above may 
involve temporary changes in behavior and short-term displacement 
within ensonified areas. There is no evidence that the planned 
activities could result in injury, serious injury, or mortality, for 
example due to collisions with

[[Page 34260]]

vessels. Disturbance reactions, such as avoidance, are very likely to 
occur amongst marine mammals in the vicinity of the source vessel. The 
mitigation and monitoring measures proposed to be implemented 
(described later in this document) during this survey are based on 
Level B harassment criteria and will minimize any potential risk to 
injury or mortality.
    The methodology used by PGS 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 
Beaufort Sea is presented here. The bowhead whale, beluga whale, and 
bearded seal density estimates are based on the estimates developed by 
LGL (2005) for the University of Alaska IHA and used here for 
consistency. The ringed seal density estimates are from Frost et al. 
(2002). Spotted seal density estimates were derived from Green et al. 
(2005; 2006; 2007) observations that spotted seals in the Beaufort Sea 
in the vicinity represent about 5 percent of all phocid seal sightings 
and then multiplying Frost et al.'s (2002) density estimates times 5 
percent.

Exposure Calculations for Marine Mammals

    In its application, PGS presented the average and maximum estimates 
of ``take,'' which were calculated by multiplying the expected average 
and maximum animal densities provided in Table 6.2-1 in the application 
by the area of ensonification. The area of ensonification was assumed 
to be the length of trackline in marine waters multiplied by the 160-dB 
and 170-dB isopleths times 2. The total length of trackline in marine 
waters is estimated at 1,280 km (795 mi), including 770 km (478 mi) 
outside the barrier islands and 510 km (317 mi) inside the barrier 
islands.
    In the PGS' application, it provides both average and maximum 
density data for the marine mammals that are likely to be adversely 
affected. These density numbers were based on survey and monitoring 
data of marine mammals in recent years in the vicinity of the proposed 
action area (LGL, 2005; Frost et al., 2002; Green et al., 2005; 2006; 
2007). In addition, PGS also provided maximum density estimates for 
those marine mammal populations. The average and maximum population 
density of marine mammals are provided in Table 6.2.1 of the PGS 
application. However, PGS did not provide a rationale regarding the 
maximum estimate or a description as to how these maximum density 
estimates were calculated. NMFS decides that the average density data 
of marine mammal populations will be used to calculate estimated take 
numbers because these numbers are based on surveys and monitoring of 
marine mammals in the vicinity of the proposed project area.
    In its review of PGS' application, NMFS determined that the safety 
radii calculated by PGS were too small based on the size and source 
level of the airgun array to be used. Therefore, NMFS requested that 
PGS submit an addendum to the IHA application, which outlined in 
greater detail the modeling techniques used. Based on this additional 
information, NMFS recalculated the distances to the 160-, 170-, 180-, 
and 190-dB isopleths, using 250 dB as the source output. Based on this 
new information, the respective radii for the 160-, 170-, 180-, and 
190-dB isopleths are: 2,894 m (1.8 mi); 1,194 m (0.74 mi); 492 m (0.31 
mi); and 203 m (0.13 mi).
    The total area of ensonification using the 160-dB criteria is 
7,398.4 km\2\ (2,856.5 mi\2\; including 4,450.6 km\2\, or 1,718.4 mi\2\ 
outside the barrier islands; and 2,947.8 km\2\, or 1,138.1 mi\2\ inside 
the barrier islands) and for the 170-dB criteria is 3,056.6 km\2\ 
(1,180.2 mi\2\; including 1,838.8 km\2\, or 710 mi\2\ outside the 
barrier islands, and 1,217.9 km\2\, or 470.2 mi\2\ inside the barrier 
islands). However, given that none of the area occurs in waters greater 
than 15 m (49 ft) deep (and half the area is in waters less than 4 m, 
13 ft, deep), which is not suitable habitat for migrating bowhead 
whales, which has been defined as waters 15-200 m (49-660 ft) deep 
(Richardson and Thomson, 2002), this calculation provides a very 
conservative estimate of potential take. Therefore, only the area 
outside the barrier islands was used in the calculations for bowhead 
whales.
    The ``take'' estimates were determined by multiplying the various 
density estimates in Table 6.2-1 by the ensonification area using the 
160-dB criteria for cetaceans and the 170-dB criteria for pinnipeds. 
However, NMFS has noted in the past that it is unaware of any empirical 
evidence to indicate that pinnipeds do not respond at the lower level 
(i.e., 160 dB). As a result, NMFS will estimate Level B harassment 
takes based on the 160-dB criterion. The bowhead and beluga density 
estimates come from LGL (2005) and the ringed seal estimates from Frost 
et al. (2002). The spotted seal densities were determined by 
multiplying the ringed seal estimate by 5 percent, a reflection of 
three years of survey results by Green et al. (2005; 2006; 2007), 
showing that spotted seals represented about 5 percent of several 
thousand phocid sightings in nearshore waters of the Beaufort Sea.
    Based on the calculation of using the average density estimates 
presented in Table 6.2-1 in PGS' application and the area of 
ensonification outlined above, it is estimated that up to approximately 
28 bowhead whales, 25 beluga whales, 1,467 ringed seals, 73 spotted 
seals, and 20 bearded seals would be affected by Level B behavioral 
harassment as a result of the proposed 3D OBC/TZ seismic survey in the 
Beaufort Sea. These take numbers represent 0.27 percent of the western 
Arctic stock of bowhead whales, 0.06 percent of the Beaufort Sea stock 
of beluga whales, and 0.59 percent, 0.12 percent, and 0.008 percent of 
the Alaska stocks of ringed, spotted, and bearded seals, respectively.
    Although gray whales are considered to be an extralimital species 
in the project area, there have been a few rare sightings in the 
Beaufort Sea east of Point Barrow in late summer and as far east as 
Smith Bay (Green et al., 2007). Currently, there are no reliable 
density or population estimates for gray whales in the project area. A 
take estimate of two gray whales has been requested. This number is 
considered minimal based on the population size of the eastern North 
Pacific stock of gray whales.
    PGS plans to continue conducting seismic surveys after August 25, 
the commencement of annual bowhead whale hunt, and the beginning of the 
fall bowhead migration. NMFS requires take estimates be evaluated out 
to the 120-dB isopleth for any operation occurring after August 25, 
unless the operator can show that their sound source would attenuate to 
less than 120 dB before reaching the normal bowhead whale migration 
lanes. Because of the downward sound directionality of the proposed 
array configuration, the radius to the 120-dB isopleth would extend out 
to about 10-15 km (6-9 mi). Further, beginning in early August, PGS 
will move their operations inside the barrier islands and remain there 
throughout the subsistence hunt and whale migration. Consequently, the 
closest 120 dB level sounds could reach migrating whales is a point 
approximately 10 km (6 mi) north of a line between Spy and Thetis 
islands. At this point the water depth is approximately 6 m (20 ft), 
less than suitable habitat for migrating bowhead whales. Further, much 
of the sound emanating from inside the barrier islands would be blocked 
by Spy, Thetis, and Leavitt Islands, leaving only a fraction of the 
survey area inside the barrier islands from which the 120-dB radius 
could even reach a point 10 km

[[Page 34261]]

(6 mi) north of barrier islands. During most of the survey inside the 
barrier islands, it is expected that the 120-dB radii would not extend 
at all outside the barrier islands since the islands will absorb the 
sound.
    However, the 120-dB radius estimate is based on modeling. Actual 
field measurements of acoustical signatures for the proposed array are 
planned at the onset of the surveys. Should these measurements 
determine that the 120-dB radius could extend into the bowhead whale 
migration corridor, additional mitigation measures will be proposed in 
conjunction with consultation with NMFS, the North Slope Borough (NSB), 
and the Alaska Eskimo Whaling Commission (AEWC).
    Because PGS plans to operate inside the barrier islands only during 
the fall, and these interior habitats typically provide less suitable 
habitat for marine mammals as compared to outside the barrier islands, 
no increase in animal densities are expected during the fall seismic 
survey. Thus, separate take estimates for the fall period were not 
calculated.

Conclusions

    Impacts of seismic sounds on cetaceans are generally expected to be 
restricted to avoidance of a limited area around the seismic operation 
and short-term changes in behavior, falling within the MMPA definition 
of Level B harassment. No Level A takes (including injury, serious 
injury, or mortality) are expected as a result of the proposed 
activities. The estimated numbers of cetaceans and pinnipeds 
potentially exposed to sound levels sufficient to cause behavioral 
disturbance are very low percentages of the population sizes in the 
Bering-Chukchi-Beaufort seas.
    Mitigation measures such as look outs, non-pursuit, shutdowns or 
power-downs when marine mammals are seen within defined ranges, and 
avoiding migration pathways when animals are likely most sensitive to 
noise will further reduce short-term reactions, and minimize any 
effects on hearing sensitivity. In all cases, the effects are expected 
to be short-term, with no lasting biological consequence. Subsistence 
issues are addressed later in this document.

Potential Impact on Habitat

    The proposed seismic survey will not result in any permanent impact 
on habitats used by marine mammals or their prey sources. Furthermore, 
seismic activity will take place in shallow, nearshore waters less than 
15 m (49 ft) deep, which is not considered to be bowhead whale habitat. 
No impacts are expected to the ocean floor or anticipated by placing 
geophones on the ocean floor.
    Relative to toothed whale and pinniped prey, a broad discussion of 
the various types of potential effects of exposure to seismic activity 
on fish and invertebrates can be found in LGL (2005). This discussion 
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 
m to 3 m, 1.6 ft to 10 ft) from the seismic source. Direct mortality 
has been observed in cod and plaice within 48 hours after they were 
subjected to seismic pulses 2 m (6.6 ft) 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 energy 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 for male 
snow crabs (Christian et al., 2003). Behavioral changes in fish 
associated with seismic exposures from project activities 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 within 
anywhere from 15-30 min (McCauley et al., 2000) to several days (Engas 
et al., 1996) after cessation of activities.
    Available data indicate that mortality and behavioral changes do 
occur within very close range to the seismic sources; however, the 
proposed seismic site clearance activity in the Beaufort Sea is 
predicted to have a negligible effect on the prey resources of the 
various life stages of fish and invertebrates available to marine 
mammals. Further, the 880 in\3\ array, proposed for this project, 
produces a relatively low energy pulse (250 dB) compared to the seismic 
systems used in the above studies.
    It is estimated that only a small portion of the marine mammals 
utilizing the areas of the proposed activities would be temporarily 
displaced. No loss of habitat is anticipated due to laying cable on the 
ocean floor.
    During the period of seismic surveying (July through mid-
September), most marine mammals would be dispersed throughout the area. 
The peak of the bowhead whale migration through the Alaskan Beaufort 
Sea typically occurs in September. Starting in late August, bowheads 
may travel in proximity to the seismic surveys and hear sounds from 
vessel traffic and seismic activity, which might temporarily displace 
some whales. In addition, feeding does not appear to be an important 
activity for bowheads migrating through the Chukchi Sea in most years; 
however, sightings of bowhead whales do occur in the summer near Barrow 
(Moore and DeMaster, 2000), and there are suggestions that certain 
areas near Barrow are important feeding grounds. In the absence of 
important feeding areas, the potential diversion of a small number of 
bowheads away from survey activities is not expected to have any 
significant or long-term consequences for individual bowheads or their 
population. Bowheads are not expected to be excluded from any habitat.
    The numbers of cetaceans and pinnipeds subject to displacement are 
very small in relation to abundance estimates for the mammals addressed 
under this IHA request. 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 and very 
nearshore location of the survey area.

Effects of Seismic Noise and Other Related Activities on Subsistence

    Subsistence hunting and fishing is historically, and continues to 
be, an essential aspect of Alaska Native life, especially in rural 
coastal villages. The Inupiat people participate in subsistence hunting 
and fishing activities in and around the Beaufort Sea. The animals 
taken for subsistence provide a significant portion of the food that 
will feed the people throughout the year. Along with providing the 
nourishment necessary for survival, subsistence activities strengthen 
bonds within the culture, provide a means for educating the young, 
provide supplies for artistic expression, and allow for important 
celebratory events.
    Only minor, temporary effects from the seismic survey project are 
anticipated on Native subsistence hunting. PGS does not expect any 
permanent impacts on marine mammals

[[Page 34262]]

that will adversely affect subsistence hunting. Mitigation efforts will 
be implemented to minimize or completely avoid any adverse effects on 
marine mammals. Additionally, areas being used for subsistence hunting 
grounds will be avoided. It is anticipated that only minor, temporary 
displacement of marine mammals will occur.
    Alaska Natives, including the Inupiat, legally hunt several species 
of marine mammals. Marine animals used for subsistence within the 
Beaufort Sea region include bowhead and beluga whales and ringed, 
spotted, and bearded seals. Each village along the Beaufort Sea hunts 
key subsistence species. Hunts for these animals occur during different 
seasons throughout the year. Depending upon the success of a village's 
hunt for a certain species, another species may become a priority in 
order to provide enough nourishment to sustain the village. Communities 
that participate in subsistence activities potentially affected by 
seismic surveys within the proposed development area are Nuiqsut and 
Barrow.
    Nuiqsut is the village nearest to the proposed seismic activity 
area. Bowhead and beluga whales and ringed, spotted, and bearded seals 
are harvested by residents of Nuiqsut. Because the village is 56 km (35 
mi) inland (Alaska community Online Database, 2008), whaling crews 
travel in aluminum skiffs equipped with outboard motors to offshore 
areas such as Cross Island (Funk and Galginaitis, 2005). Of the marine 
mammals harvested, bowhead whales are most commonly harvested. In 1992 
an estimated 34,884 kg (76,906 lbs) were harvested (ADF&G, 2008). Seals 
are also regularly hunted and may account for up to 3,770 kg (8,310 
lbs) of harvest, while beluga whale harvests account for little or none 
(ADF&G, 2008).
    Barrow residents' main subsistence focus is concentrated on 
biannual bowhead whale hunts that take place during the spring and 
fall. Other animals, such as seals, are hunted outside of the whaling 
season, but they are not the primary source of the subsistence harvest 
(URS Corp., 2005).

Bowhead Whales

    The bowhead whales that could potentially be affected by seismic 
activity in the Beaufort Sea come from the Western Arctic stock. The 
majority of these whales migrate annually during the spring from 
wintering grounds in the Bering Sea, through the Chukchi Sea, to summer 
grounds in the Beaufort Sea. During the fall migration, the whales 
travel back through the Chukchi Sea to their wintering grounds in the 
Bering Sea. While on their spring migration route, bowhead whales 
travel through leads in the ice between the shore-fast ice and pack 
ice.
    In a study of approximately 440 bowhead whales between 1989 and 
1994 off the coast of Point Barrow, Richardson et al. (1995) documented 
movements and behaviors in response to playback of sounds similar to 
those produced by site clearance and shallow hazard surveys. Whale 
behavior in relation to the sound level being received at the whales' 
locations was observed. The research team concluded that the sounds 
emitted did not have a biologically significant effect on bowhead 
movement, distribution, or behavior.
    Ten primary coastal Alaskan villages deploy whaling crews during 
whale migrations. Of these ten, Nuiqsut has the potential to be 
affected by the proposed project, as it is the village situated closest 
to the proposed project area. Barrow is located farther from the 
proposed seismic activity but has the potential to be affected. These 
two communities are part of the AEWC. The AEWC was formed as a response 
to the International Whaling Commission's past closure of bowhead whale 
hunting for subsistence purposes. IWC sets a quota for the whale hunt, 
and AEWC allocates the quota between villages. Each of the villages 
within the AEWC is represented by a Whaling Captains' Association. 
Bowhead whales migrate within the hunting range of whaling crews in the 
spring (north migration) and the fall (south migration). In the spring, 
the whales must travel through leads in the ice that tend to occur 
close to shore. In the fall, the water is much more open, allowing the 
whales to swim farther from the coast.
    Whaling crews in Barrow hunt in both the spring and the fall (Funk 
and Galginaitis, 2005). In the spring, the whales are hunted along 
leads that occur when the pack ice starts deteriorating. This tends to 
occur in Barrow between the first week of April and the first week of 
June, well before the geophysical surveys will be conducted. The 
proposed seismic survey is anticipated to start after all the ice 
melts, in approximately mid-July, and will not affect spring whaling. 
Fall whaling activities are anticipated to take place east of Point 
Barrow (BLM, 2005). The project area is located 260 km (160 mi) east of 
Point Barrow. It is anticipated that the project will not impact the 
Barrow fall hunt. The Nuiqsut fall whale hunt takes place in the 
vicinity of Cross Island, ranging from there to approximately 50 km (30 
mi) north of the island. The project area is located approximately 60 
km (37 mi) west of Cross Island and is too shallow (less than 15 m, 50 
ft deep) to support bowhead whales. It is unlikely that the Nuiqsut 
fall hunt would extend to the project area. Adverse impacts on the 
subsistence harvest of bowhead whales as a result of the proposed 
survey are not anticipated.

Beluga Whales

    Beluga whales summer in the waters of the Chukchi and Beaufort Seas 
and winter in the Bering Sea. Living in areas mostly covered in ice, 
they are associated with leads and polynyas (Haard, 1988). Beluga 
whales can be hunted from the first week in April to July or August. It 
is common for the Inupiat to refrain from hunting beluga during the 
spring or fall bowhead whale hunt to prevent scaring the larger whales 
away from hunting locations. Belugas do not account for a majority of 
the total subsistence harvest in Barrow or Nuiqsut (ADF&G, 2008). 
Between 1999 and 2003, the annual beluga subsistence ``take'' was 65 
(Frost and Suydam, 1995).

Ringed Seals

    Ringed seals are distributed throughout the Arctic Ocean. They 
inhabit both seasonal and permanent ice. An abundance and distribution 
study conducted in the Beaufort Sea before, during, and after 
anthropogenic sound-producing construction found that there were only 
slight changes near construction activities around British Petroleum's 
(BP's) Northstar oil development that most likely were caused by 
environmental factors (Moulton et al., 2005). Harris et al. (2001) 
performed a study using 3D seismic arrays in which the number of seal 
sightings varied only slightly in periods of no sonar firing, single 
sonar firing, and multiple-array sonar firing. Seals tended to stay 
slightly farther away from the vessel at times of full-array sonar 
firing, but they rarely moved more than 250 m (820 ft) from the vessel. 
Sonar activity was interrupted when seals came within a certain radius 
(150 m, 492 ft, to 250 m, 820 ft) of the vessel, in accordance with 
regulations set by NMFS.
    Ringed seals are available to subsistence users year-round, but 
they are primarily hunted in the winter due to the rich availability of 
other mammals in the summer. In 2000, the annual estimated subsistence 
``take'' from Alaska of ringed seals was 9,567. Because the bulk of the 
ringed seal hunting will occur outside the time scope of the proposed 
project, adverse

[[Page 34263]]

impacts on ringed seals as a result of the proposed survey are not 
anticipated.

Spotted Seals

    Spotted seals in Alaska are distributed along the continental shelf 
of the Beaufort, Chukchi, and Bering Seas. These seals migrate south 
from the Chukchi Sea, through the Bering Strait, into the Bering Sea 
beginning in October. They spend the winter in the Bering Sea traveling 
east and west along the ice edge (Lowry et al., 1998). Because of the 
numbers of whales and bearded seals and the opportunities for 
subsistence harvesting of them, spotted and ringed seals are primarily 
hunted during winter months in the Beaufort Sea. Since this time frame 
is outside the scope of the proposed project, subsistence activities 
involving spotted and ringed seals are unlikely to occur during the 
survey (BLM, 2005). PGS does not anticipate adverse effects to spotted 
seals as a result of project activities.

Bearded Seals

    Bearded seals tend to inhabit relatively shallow water (less than 
200 m, 656 ft, deep) that does not have much ice. In Alaska, they are 
distributed along the continental shelf of the Bering, Chukchi, and 
Beaufort Seas. Most bearded seals migrate in the spring from the Bering 
Sea, through the Bering Strait, and into the Chukchi Sea and spend the 
summer season along the ice edge. Some bearded seals do not migrate and 
spend all year in the waters of the Bering and Chukchi Seas. According 
to a subsistence harvest database, the 2000 annual harvest of bearded 
seals in Alaska was 6,788 (ADF&G, 2000). Bearded seals are an important 
source of meat and hide for Chukchi Sea villages. They tend to be 
targeted by subsistence users over ringed and spotted seals because 
they are very large. This provides a large amount of meat and skins for 
constructing boats (BLM, 2005).
    Bearded seals are primarily hunted during July in the Beaufort Sea; 
however, in 2007, bearded seals were harvested in the months of August 
and September at the mouth of the Colville River Delta (Smith, pers. 
comm., 2008). The proposed project location is not a primary 
subsistence hunting ground; however, it is occasionally used by 
residents of Nuiqsut for subsistence hunting of bearded seals. An 
annual bearded seal harvest occurs in the vicinity of Thetis Island in 
July through August (J. Nukapigak, Nuiqsut hunter, pers. comm., 2008). 
Approximately 20 bearded seals are harvested annually through this 
hunt.
    PGS anticipates that there is not a significant potential for the 
proposed project to affect the bearded seal subsistence hunt. 
Mitigation measures will be in place to minimize potential impacts.

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. PGS developed a Draft POC, which 
included a timeline of meetings set to occur in the communities 
identified as potentially being affected by the proposed project. These 
communities are Nuiqsut and Barrow. The Draft POC document was 
distributed to the communities, subsistence users groups, NMFS, and 
USFWS on March 20, 2008. Based upon discussions with communities and 
subsistence users, PGS has incorporated changes to the project to 
reduce potential subsistence conflicts. These changes are discussed in 
Addendum 1 of the Draft POC, which was submitted to the potentially 
affected communities and subsistence users groups, NMFS, and USFWS on 
May 7, 2008. Copies were also available during POC meetings in Barrow 
on May 8, 2008, and in Nuiqsut on May 9, 2008. A Final POC document 
including all input from potentially affected communities and 
subsistence users groups will be provided upon completion of the May 
POC meetings. Meetings that have taken place prior to the survey 
include:
     February 7, 2008: AEWC 2008 Conflict Avoidance Agreement 
(CAA) meeting with Nuiqsut whalers in Deadhorse to present the proposed 
projec