[Federal Register Volume 76, Number 100 (Tuesday, May 24, 2011)]
[Notices]
[Pages 30110-30130]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-12666]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XA396


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Shallow Hazards Survey in the 
Chukchi Sea, Alaska

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

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

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SUMMARY: NMFS received an application from Statoil USA E&P Inc. 
(Statoil) for an Incidental Harassment Authorization (IHA) to take 
marine mammals, by harassment, incidental to a proposed open water 
shallow hazards survey in the Chukchi Sea, Alaska, between July through 
November 2011. Pursuant to the Marine Mammal Protection Act (MMPA), 
NMFS is requesting comments on its proposal to issue an IHA to Statoil 
to take, by Level B harassment only, thirteen species of marine mammals 
during the specified activity.

DATES: Comments and information must be received no later than June 23, 
2011.

ADDRESSES: Comments on the application should be addressed to Michael 
Payne, Chief, Permits, Conservation and Education Division, Office of 
Protected Resources, National Marine Fisheries Service, 1315 East-West 
Highway, Silver Spring, MD 20910. The mailbox address for providing e-
mail comments is [email protected]. NMFS is not responsible for e-mail 
comments sent to addresses other than the one provided here. Comments 
sent via e-mail, including all attachments, must not exceed a 10-
megabyte file size.
    Instructions: All comments received are a part of the public record 
and will generally be posted to http://www.nmfs.noaa.gov/pr/permits/incidental.htm without change. All Personal Identifying Information 
(for example, name, address, etc.) voluntarily submitted by the 
commenter may be publicly accessible. Do not submit Confidential 
Business Information or otherwise sensitive or protected information.
    A copy of the application used in this document may be obtained by 
writing to the address specified above, telephoning the contact listed 
below (see FOR

[[Page 30111]]

FURTHER INFORMATION CONTACT), or visiting the Internet at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm. Documents cited in this 
notice may also be viewed, by appointment, during regular business 
hours, at the aforementioned address.

FOR FURTHER INFORMATION CONTACT: Shane Guan, Office of Protected 
Resources, NMFS, (301) 713-2289, ext 137.

SUPPLEMENTARY INFORMATION:

Background

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

Summary of Request

    NMFS received an application on March 1, 2011, from Statoil for the 
taking, by harassment, of marine mammals incidental to shallow hazards 
site surveys and soil investigations (geotechnical boreholes) in the 
Chukchi Sea, Alaska, during the 2011 open-water season. After 
addressing comments from NMFS, Statoil modified its application and 
submitted a revised application on April 19, 2011. The April 19, 2011, 
application is the one available for public comment (see ADDRESSES) and 
considered by NMFS for this proposed IHA.
    The proposed shallow hazards and site clearance surveys would use a 
towed airgun cluster consisting of four, 10-in\3\ airguns with a ~600 m 
towed hydrophone streamer, as well as additional lower-powered and 
higher frequency survey equipment for collecting bathymetric and 
shallow sub-bottom data. The proposed survey will take place on and 
near Statoil's leases in the Chukchi Sea, covering a total area of ~665 
km\2\ located ~240 km (150 mi) west of Barrow and ~165 km (103 mi) 
northwest of Wainwright, in water depths of ~30-50 m (100-165 ft).
    The proposed geotechnical soil investigations will take place at 
prospective drilling locations on Statoil's leases and leases jointly 
owned with ConocoPhillips Alaska Inc. (CPAI). All cores will be either 
2.1 in. or 2.8 in. in diameter (depending on soil type) and those 
collected at prospective drilling locations will be up to 100 m in 
depth. The maximum total number of samples collected as part of the 
drilling location and site survey program will be ~29.
    Statoil intends to conduct these marine surveys during the 2011 
Arctic open-water season (July through November). Impacts to marine 
mammals may occur from noise produced from active acoustic sources 
(including airguns) used in the surveys.

Description of the Specified Activity

    Statoil acquired 16 leases in the Chukchi Sea during Lease Sale 193 
held in February 2008. The leased areas are located ~240 km (150 mi) 
west of Barrow and ~160 km (~100 mi) northwest of Wainwright. During 
the open-water season of 2010, Statoil conducted a 3D seismic survey 
over its lease holdings and the surrounding area. The data gathered 
during that survey are currently being analyzed in order to determine 
potential well locations on the leases. These analyses will be 
completed prior to commencement of the site survey program. During the 
open-water season of 2011, Statoil proposes to conduct shallow hazards 
and site clearance surveys (site surveys) and soil investigations 
(geotechnical boreholes).
    The proposed operations will be performed from two different 
vessels. Shallow hazards surveys will be conducted from the M/V Duke, 
while geotechnical soil investigations will be conducted from the M/V 
Fugro Synergy (see Statoil's application for vessel specifications). 
Both vessels will mobilize from Dutch Harbor in late July and arrive in 
the Chukchi Sea to begin work on or after 1 August. Allowing for poor 
weather days, operations are expected to continue into late September 
or early October. However, if weather permits and all planned 
activities have not been completed, operations may continue as late as 
15 November.
    The site survey work on Statoil's leases will require approximately 
23 days to complete. Geotechnical soil investigations on Statoil leases 
and on leases jointly held with CPAI will require ~14 days of 
operations.

Shallow Hazards and Site Clearance Surveys

    Shallow hazards site surveys are designed to collect bathymetric 
and shallow sub-seafloor data that allow the evaluation of potential 
shallow faults, gas zones, and archeological features at prospective 
exploration drilling locations, as required by the Bureau of Ocean 
Energy Management, Regulation, and Enforcement (BOEMRE). Data are 
typically collected using multiple types of acoustic equipment. During 
the site surveys, Statoil proposes to use the following acoustic 
sources: 4x10 in\3\ airgun cluster, single 10 in\3\ airgun, Kongsberg 
SBP3000 sub-bottom profiler, GeoAcoustics 160D side-scan sonar, and a 
Kongsberg EM2040 multi-beam echosounder. The operating frequencies and 
estimated source levels of this equipment are provided below.
1. Airguns
    A 4x10 in\3\ airgun cluster will be used to obtain geological data 
during the shallow hazards survey. A similar airgun cluster was 
measured by Shell in 2009 during shallow hazards surveys on their 
nearby Burger prospect (Reiser et al. 2010). The measurements resulted 
in 90th percentile propagation loss equations of RL =

[[Page 30112]]

218.0-17.5LogR-0.00061R for a 4x10 in\3\ airgun cluster and RL = 204.4-
16.0LogR-0.00082R for a single 10 in\3\ airgun (where RL = received 
level and R = range). The estimated 190, 180, and 160 dBrms 
re 1 [mu]Pa isopleths are estimated at 39 m, 150 m, and 1,800 m from 
the source. More accurate isopleths at these received levels will be 
established prior to Statoil's shallow hazards survey (see below).
2. Kongsberg SBP300 Sub-Bottom Profiler
    This instrument will be operated from the M/V Duke during site 
survey operations. This sub-bottom profiler operates at frequencies 
between 2 and 7 kHz with a manufacturer specified source level of ~225 
dB re 1 [mu]Pa-m. The sound energy is projected downwards from the hull 
in a maximum 15[deg] cone. However, field measurements of similar 
instruments in previous years have resulted in much lower actual source 
levels (range 161-186 dB) than specified by the manufacturers (i.e. the 
manufacturer source level of one instrument was reported as 214 dB, and 
field measurements resulted in a source level estimate of 186.2 dB) 
(Reiser et al. 2010). Although it is not known whether these field 
measurements captured the narrow primary beam produced by the 
instruments, Statoil will measure the sounds produced by this 
instrument (and all other survey equipment) at the start of operations 
and if sounds from the instrument are found to be above mitigation 
threshold levels (180 dB for cetaceans, 190 dB for seals) at a distance 
beyond the footprint of the vessel, then the same power-down and shut-
down mitigation measures used during airgun operations will be employed 
during use of the sub-bottom profiler.
3. GeoAcoustics 160D Side-Scan Sonar
    The side-scan sonar will be operated from the M/V Duke during site 
survey operations. This unit operates at 114 kHz and 410 kHz with a 
source level of ~233 dB re 1 [mu]Pa-m. The sound energy is emitted in a 
fan shaped pattern that is narrow (0.3-1.0[deg]) in the fore/aft 
direction of the vessel and broad (40-50[deg]) in the port/starboard 
direction.
4. Kongsberg EM2040 Multi-Beam Echosounder
    Multi-beam echosounders also emit energy in a fan-shaped pattern, 
similar to the side-scan sonar described above. This unit operates at 
200 to 400 kHz with a source level of ~210 dB re 1 [mu]Pa-m. The beam 
width is 1.5[deg] in the fore/aft direction. The multi-beam echosounder 
will be operated from the M/V Duke during site surveys operations.

Geotechnical Soil Investigations

    Geotechnical soil investigations are performed to collect detailed 
data on seafloor sediments and geological structure to a maximum depth 
of 100 m. These data are then evaluated to help determine the 
suitability of the site as a drilling location. Statoil has contracted 
with Fugro who will use the vessel M/V Fugro Synergy to complete the 
planned soil investigations. Three to four bore holes will be collected 
at each of up to 5 prospective drilling locations on Statoil's leases 
and up to 3 boreholes may be completed at each of up to 3 potential 
drilling locations on leases jointly owned with CPAI. This would result 
in a maximum total of 29 bore holes to be completed as part of the 
geotechnical soil investigation program. The Fugro Synergy operates a 
Kongsberg EA600 Echosounder and uses a Kongsberg 500 high precision 
acoustic positioning (HiPAP) system for precise vessel positioning 
while completing the boreholes. The operating frequencies and estimated 
source levels of the acoustic equipment, as well as the sounds produced 
during soil investigation sampling, are provided in the sub-section 
below.
1. Kongsberg EA600 Echosounder
    This echosounder will be operated from the M/V Fugro Synergy 
routinely as a fathometer to provide depth information to the bridge 
crew. This model is capable of simultaneously using 4 transducers, each 
with a separate frequency. However, only 2 transducers will be mounted 
and used during this project. These transducers will operate at 18 kHz 
and 200 kHz and have similar or slightly lower source levels than the 
multi-beam echosounder described above. The energy from these 
transducers is emitted in a conical beam from the hull of the vessel 
downward to the seafloor.
2. Kongsberg HiPAP 500
    The Kongsberg high precision acoustic positioning system (HiPAP) 
500 is used to aid the positioning of the M/V Fugro Synergy during soil 
investigation operations. An acoustic signal is sent and received by a 
transponder on the hull of the vessel and a transponder lowered to the 
seafloor near the borehole location. The two transponders communicated 
via signals with a frequency of between 21-30.5 kHz with source levels 
expected to be in the 200-210 dB range.
3. Geotechnical Soil Investigation Sounds
    In-water sounds produced during soil investigation operations by 
the M/V Fugro Synergy have not previously been measured and estimates 
of such activities vary. Measurements of another Fugro vessel that 
often conducts soil investigations were made in the Gulf of Mexico in 
2009. However, because measurements were taken using a towed hydrophone 
system, recordings of soil investigation related sounds could not be 
made while the vessel was stationary. Therefore, sounds recorded while 
the vessel was in transit were compared to sounds recorded while the 
vessel also operated generators and mechanical equipment associated 
with soil investigation operations while in transit. The difference in 
sound levels during transit alone and during transit with soil 
investigation equipment operating was negligible and this was 
attributed to the fact that transit noise was dominant up to at least 7 
kHz and likely masked the lower frequency sounds produced by the 
simulated soil investigation activities.
4. Dynamic Positioning Sound
    During soil investigation operations, the M/V Fugro Synergy will 
remain stationary relative to the seafloor by means of a dynamic 
positioning (DP) system that automatically controls and coordinates 
vessel movements using bow and/or stern thrusters as well as the 
primary propeller(s). The sounds produced by soil investigation 
equipment are not likely to substantially increase overall source 
levels beyond those produced by the various thrusters while in DP mode. 
Measurements of a vessel in DP mode with an active bow thruster were 
made in the Chukchi Sea in 2010 (Chorney et al. 2011). The resulting 
source level estimate was 175.9 dBrms re 1 [mu]Pa-m. Using 
the transmission loss equation from measurements of a single 60 in\3\ 
airgun on Statoil's lease in 2010 (RL = 205.6-13.9LogR-0.00093R; 
O'Neill et al. 2011) and replacing the constant term with the 175.9 
results in an estimated range of 4.97 km to the 120 dB level. To allow 
for uncertainties and some additional sound energy being contributed by 
the operating soil investigation equipment, an inflation factor of 1.5 
was applied to arrive at an estimated >= 120 dB radius of 7.5 km for 
soil investigation activities.

Description of Marine Mammals in the Area of the Specified Activity

    Nine cetacean and four seal species could occur in the general area 
of the

[[Page 30113]]

site clearance and shallow hazards survey. The marine mammal species 
under NMFS's jurisdiction most likely to occur near operations in the 
Chukchi and Beaufort seas include four cetacean species: Beluga whale 
(Delphinapterus leucas), bowhead whale (Balaena mysticetus), gray whale 
(Eschrichtius robustus), and harbor porpoise (Phocoena phocoena), and 
three seal species: ringed (Phoca hispida), spotted (P. largha), and 
bearded seals (Erignathus barbatus). The marine mammal species that is 
likely to be encountered most widely (in space and time) throughout the 
period of the planned site clearance and shallow hazards surveys is the 
ringed seal.
    Other marine mammal species that have been observed in the Chukchi 
Sea but are less frequent or uncommon in the project area include 
narwhal (Monodon monoceros), killer whale (Orcinus orca), fin whale 
(Balaenoptera physalus), minke whale (B. acutorostrata), humpback whale 
(Megaptera novaeangliae), and ribbon seal (Histriophoca fasciata). 
These species could occur in the project area, but each of these 
species is uncommon or rare in the area and relatively few encounters 
with these species are expected during the proposed shallow hazards 
survey. The narwhal occurs in Canadian waters and occasionally in the 
Beaufort Sea, but it is rare there and is not expected to be 
encountered. There are scattered records of narwhal in Alaskan waters, 
including reports by subsistence hunters, where the species is 
considered extralimital (Reeves et al. 2002).
    The bowhead, fin, and humpback whales are listed as ``endangered'' 
under the Endangered Species Act (ESA) and as depleted under the MMPA. 
Certain stocks or populations of gray, beluga, and killer whales and 
spotted seals are listed as endangered or proposed for listing under 
the ESA; however, none of those stocks or populations occur in the 
proposed activity area. Additionally, the ribbon seal is considered a 
``species of concern'' under the ESA, and the bearded and ringed seals 
are ``candidate species'' under the ESA, meaning they are currently 
being considered for listing.
    Statoil's application contains information on the status, 
distribution, seasonal distribution, and abundance of each of the 
species under NMFS jurisdiction mentioned in this document. Please 
refer to the application for that information (see ADDRESSES). 
Additional information can also be found in the NMFS Stock Assessment 
Reports (SAR). The Alaska 2010 SAR is available at: http://www.nmfs.noaa.gov/pr/pdfs/sars/ak2010.pdf.

Potential Effects of the Specified Activity on Marine Mammals

    Operating active acoustic sources such as an airgun array has the 
potential for adverse effects on marine mammals.

Potential Effects of Airgun Sounds on Marine Mammals

    The effects of sounds from airgun pulses might include one or more 
of the following: tolerance, masking of natural sounds, behavioral 
disturbance, and temporary or permanent hearing impairment or non-
auditory effects (Richardson et al. 1995). As outlined in previous NMFS 
documents, the effects of noise on marine mammals are highly variable, 
and can be categorized as follows (based on Richardson et al. 1995):
(1) Tolerance
    Numerous studies have shown that pulsed sounds from airguns are 
often readily detectable in the water at distances of many kilometers. 
Numerous studies have also shown that marine mammals at distances more 
than a few kilometers from operating survey vessels often show no 
apparent response. That is often true even in cases when the pulsed 
sounds must be readily audible to the animals based on measured 
received levels and the hearing sensitivity of that mammal group. 
Although various baleen whales, toothed whales, and (less frequently) 
pinnipeds have been shown to react behaviorally to airgun pulses under 
some conditions, at other times, mammals of all three types have shown 
no overt reactions. In general, pinnipeds and small odontocetes seem to 
be more tolerant of exposure to airgun pulses than baleen whales.
(2) Behavioral Disturbance
    Marine mammals may behaviorally react to sound when exposed to 
anthropogenic noise. These behavioral reactions are often shown as: 
changing durations of surfacing and dives, number of blows per 
surfacing, or moving direction and/or speed; reduced/increased vocal 
activities; changing/cessation of certain behavioral activities (such 
as socializing or feeding); visible startle response or aggressive 
behavior (such as tail/fluke slapping or jaw clapping); avoidance of 
areas where noise sources are located; and/or flight responses (e.g., 
pinnipeds flushing into water from haulouts or rookeries).
    The biological significance of many of these behavioral 
disturbances is difficult to predict, especially if the detected 
disturbances appear minor. However, the consequences of behavioral 
modification could be expected to be biologically significant if the 
change affects growth, survival, and reproduction. Some of these 
significant behavioral modifications include:
     Drastic change in diving/surfacing patterns (such as those 
thought to be causing beaked whale stranding due to exposure to 
military mid-frequency tactical sonar);
     Habitat abandonment due to loss of desirable acoustic 
environment; and
     Cease feeding or social interaction.
    For example, at the Guerreo Negro Lagoon in Baja California, 
Mexico, which is one of the important breeding grounds for Pacific gray 
whales, shipping and dredging associated with a salt works may have 
induced gray whales to abandon the area through most of the 1960s 
(Bryant et al. 1984). After these activities stopped, the lagoon was 
reoccupied, first by single whales and later by cow-calf pairs.
    The onset of behavioral disturbance from anthropogenic noise 
depends on both external factors (characteristics of noise sources and 
their paths) and the receiving animals (hearing, motivation, 
experience, demography) and is also difficult to predict (Southall et 
al. 2007).
    Currently NMFS uses 160 dB re 1 [mu]Pa at received level for 
impulse noises (such as airgun pulses) as the onset of marine mammal 
behavioral harassment.
(3) Masking
    Chronic exposure to excessive, though not high-intensity, noise 
could cause masking at particular frequencies for marine mammals that 
utilize sound for vital biological functions. Masking can interfere 
with detection of acoustic signals such as communication calls, 
echolocation sounds, and environmental sounds important to marine 
mammals. Since marine mammals depend on acoustic cues for vital 
biological functions, such as orientation, communication, finding prey, 
and avoiding predators, marine mammals that experience severe acoustic 
masking will have reduced fitness in survival and reproduction.
    Masking occurs when noise and signals (that the animal utilizes) 
overlap at both spectral and temporal scales. For the airgun noise 
generated from the proposed site clearance and shallow hazards surveys, 
noise will consist of low frequency (under 1 kHz) pulses with extremely 
short durations (in the scale of milliseconds). Lower frequency man-
made noises are more likely to affect detection of communication calls 
and other potentially important natural

[[Page 30114]]

sounds such as surf and prey noise. There is little concern regarding 
masking near the noise source due to the brief duration of these pulses 
and relatively longer silence between airgun shots (9-12 seconds). 
However, at long distances (over tens of kilometers away), due to 
multipath propagation and reverberation, the durations of airgun pulses 
can be ``stretched'' to seconds with long decays (Madsen et al. 2006). 
Therefore it could affect communication signals used by low frequency 
mysticetes when they occur near the noise band and thus reduce the 
communication space of animals (e.g., Clark et al. 2009) and cause 
increased stress levels (e.g., Foote et al. 2004; Holt et al. 2009). 
Nevertheless, the intensity of the noise is also greatly reduced at 
such long distances (for example, the modeled received level drops 
below 120 dB re 1 [mu]Pa rms at 14,900 m from the source).
    Marine mammals are thought to be able to compensate for masking by 
adjusting their acoustic behavior such as shifting call frequencies, 
increasing call volume and vocalization rates. For example, blue whales 
are found to increase call rates when exposed to seismic survey noise 
in the St. Lawrence Estuary (Di Iorio and Clark 2010). The North 
Atlantic right whales (Eubalaena glacialis) exposed to high shipping 
noise increase call frequency (Parks et al. 2007), while some humpback 
whales respond to low-frequency active sonar playbacks by increasing 
song length (Miller el al. 2000).
(4) Hearing Impairment
    Marine mammals exposed to high intensity sound repeatedly or for 
prolonged periods can experience hearing threshold shift (TS), which is 
the loss of hearing sensitivity at certain frequency ranges (Kastak et 
al. 1999; Schlundt et al. 2000; Finneran et al. 2002; 2005). TS can be 
permanent (PTS), in which case the loss of hearing sensitivity is 
unrecoverable, or temporary (TTS), in which case the animal's hearing 
threshold will recover over time (Southall et al. 2007). Just like 
masking, marine mammals that suffer from PTS or TTS will have reduced 
fitness in survival and reproduction, either permanently or 
temporarily. Repeated noise exposure that leads to TTS could cause PTS. 
For transient sounds, the sound level necessary to cause TTS is 
inversely related to the duration of the sound.
    Experiments on a bottlenose dolphin (Tursiops truncates) and beluga 
whale showed that exposure to a single watergun impulse at a received 
level of 207 kPa (or 30 psi) peak-to-peak (p-p), which is equivalent to 
228 dB re 1 [mu]Pa (p-p), resulted in a 7 and 6 dB TTS in the beluga 
whale at 0.4 and 30 kHz, respectively. Thresholds returned to within 2 
dB of the pre-exposure level within 4 minutes of the exposure (Finneran 
et al. 2002). No TTS was observed in the bottlenose dolphin. Although 
the source level of pile driving from one hammer strike is expected to 
be much lower than the single watergun impulse cited here, animals 
being exposed for a prolonged period to repeated hammer strikes could 
receive more noise exposure in terms of SEL than from the single 
watergun impulse (estimated at 188 dB re 1 [mu]Pa\2\-s) in the 
aforementioned experiment (Finneran et al. 2002).
    For baleen whales, there are no data, direct or indirect, on levels 
or properties of sound that are required to induce TTS. The frequencies 
to which baleen whales are most sensitive are lower than those to which 
odontocetes are most sensitive, and natural ambient noise levels at 
those low frequencies tend to be higher (Urick 1983). As a result, 
auditory thresholds of baleen whales within their frequency band of 
best hearing are believed to be higher (less sensitive) than are those 
of odontocetes at their best frequencies (Clark and Ellison, 2004). 
From this, it is suspected that received levels causing TTS onset may 
also be higher in baleen whales. However, no cases of TTS are expected 
given the small size of the airguns proposed to be used and the strong 
likelihood that baleen whales (especially migrating bowheads) would 
avoid the approaching airguns (or vessel) before being exposed to 
levels high enough for there to be any possibility of TTS.
    In pinnipeds, TTS thresholds associated with exposure to brief 
pulses (single or multiple) of underwater sound have not been measured. 
Initial evidence from prolonged exposures suggested that some pinnipeds 
may incur TTS at somewhat lower received levels than do small 
odontocetes exposed for similar durations (Kastak et al. 1999, 2005; 
Ketten et al. 2001). However, more recent indications are that TTS 
onset in the most sensitive pinniped species studied (harbor seal, 
which is closely related to the ringed seal) may occur at a similar SEL 
as in odontocetes (Kastak et al., 2004).
    NMFS (1995, 2000) concluded that cetaceans and pinnipeds should not 
be exposed to pulsed underwater noise at received levels exceeding, 
respectively, 180 and 190 dB re 1 [mu]Pa rms. The established 180- and 
190-dB re 1 [mu]Pa rms criteria are not considered to be the levels 
above which TTS might occur. Rather, they are the received levels above 
which, in the view of a panel of bioacoustics specialists convened by 
NMFS before TTS measurements for marine mammals started to become 
available, one could not be certain that there would be no injurious 
effects, auditory or otherwise, to marine mammals. As summarized above, 
data that are now available imply that TTS is unlikely to occur unless 
bow-riding odontocetes are exposed to airgun pulses much stronger than 
180 dB re 1 [mu]Pa rms (Southall et al. 2007).
    No cases of TTS are expected as a result of Statoil's proposed 
activities given the small size of the source, the strong likelihood 
that baleen whales (especially migrating bowheads) would avoid the 
approaching airguns (or vessel) before being exposed to levels high 
enough for there to be any possibility of TTS, and the mitigation 
measures proposed to be implemented during the survey described later 
in this document.
    There is no empirical evidence that exposure to pulses of airgun 
sound can cause PTS in any marine mammal, even with large arrays of 
airguns (see Southall et al., 2007). However, given the possibility 
that mammals close to an airgun array might incur TTS, there has been 
further speculation about the possibility that some individuals 
occurring very close to airguns might incur PTS. Single or occasional 
occurrences of mild TTS are not indicative of permanent auditory damage 
in terrestrial mammals. Relationships between TTS and PTS thresholds 
have not been studied in marine mammals, but are assumed to be similar 
to those in humans and other terrestrial mammals. That is, PTS might 
occur at a received sound level magnitudes higher than the level of 
onset TTS, or by repeated exposure to the levels that cause TTS. 
Therefore, by means of preventing the onset of TTS, it is highly 
unlikely that marine mammals could receive sounds strong enough (and 
over a sufficient duration) to cause permanent hearing impairment 
during the proposed marine surveys in the Chukchi Sea.
(5) Non-Auditory Physical Effects
    Non-auditory physical effects might occur in marine mammals exposed 
to strong underwater pulsed sound. Possible types of non-auditory 
physiological effects or injuries that theoretically might occur in 
mammals close to a strong sound source include stress, neurological 
effects, bubble formation, and other types of organ or tissue damage. 
Some marine mammal species (i.e., beaked whales) may be

[[Page 30115]]

especially susceptible to injury and/or stranding when exposed to 
strong pulsed sounds. However, there is no definitive evidence that any 
of these effects occur even for marine mammals in close proximity to 
large arrays of airguns, and beaked whales do not occur in the proposed 
project area. In addition, marine mammals that show behavioral 
avoidance of seismic vessels, including most baleen whales, some 
odontocetes (including belugas), and some pinnipeds, are especially 
unlikely to incur non-auditory impairment or other physical effects. 
The small airgun array proposed to be used by Statoil would only have 
190 and 180 dB distances of 35 and 125 m (115 and 410 ft), 
respectively.
    Therefore, it is unlikely that such effects would occur during 
Statoil's proposed surveys given the brief duration of exposure and the 
planned monitoring and mitigation measures described later in this 
document.
(6) Stranding and Mortality
    Marine mammals close to underwater detonations of high explosive 
can be killed or severely injured, and the auditory organs are 
especially susceptible to injury (Ketten et al. 1993; Ketten 1995). 
Airgun pulses are less energetic and their peak amplitudes have slower 
rise times. To date, there is no evidence that serious injury, death, 
or stranding by marine mammals can occur from exposure to airgun 
pulses, even in the case of large airgun arrays.
    However, in numerous past IHA notices for seismic surveys, 
commenters have referenced two stranding events allegedly associated 
with seismic activities, one off Baja California and a second off 
Brazil. NMFS has addressed this concern several times, and, without new 
information, does not believe that this issue warrants further 
discussion. For information relevant to strandings of marine mammals, 
readers are encouraged to review NMFS' response to comments on this 
matter found in 69 FR 74905 (December 14, 2004), 71 FR 43112 (July 31, 
2006), 71 FR 50027 (August 24, 2006), and 71 FR 49418 (August 23, 
2006). In addition, a May-June 2008, stranding of 100-200 melon-headed 
whales (Peponocephala electra) off Madagascar that appears to be 
associated with seismic surveys is currently under investigation (IWC 
2009).
    It should be noted that strandings related to sound exposure have 
not been recorded for marine mammal species in the Beaufort and Chukchi 
seas. NMFS notes that in the Beaufort Sea, aerial surveys have been 
conducted by BOEMRE (formerly the Minerals Management Service or MMS) 
and industry during periods of industrial activity (and by MMS during 
times with no activity). No strandings or marine mammals in distress 
have been observed during these surveys and none have been reported by 
North Slope Borough inhabitants. As a result, NMFS does not expect any 
marine mammals will incur serious injury or mortality in the Arctic 
Ocean or strand as a result of the proposed shallow hazards survey.

Potential Effects From Active Sonar Equipment on Marine Mammals

    Several active acoustic sources other than the four 10 in\3\ airgun 
have been proposed for Statoil's 2011 open water shallow hazards survey 
in the Chukchi Sea. The specifications of this sonar equipment (source 
levels and frequency ranges) are provided above. In general, the 
potential effects of this equipment on marine mammals are similar to 
those from the airgun, except the magnitude of the impacts is expected 
to be much less due to the lower intensity and higher frequencies. 
Estimated source levels from sonar equipment are discussed above. In 
some cases, due to the fact that the operating frequencies of some of 
this equipment (e.g., Multi-beam echosounder: Frequency at 200-400 kHz) 
are above the hearing ranges of marine mammals, they are not expected 
to have any impacts to marine mammals.

Vessel Sounds

    In addition to the noise generated from seismic airguns and active 
sonar systems, various types of vessels will be used in the operations, 
including source vessel and vessel used for geotechnical soil 
investigations. Sounds from boats and vessels have been reported 
extensively (Greene and Moore 1995; Blackwell and Greene 2002; 2005; 
2006). Numerous measurements of underwater vessel sound have been 
performed in support of recent industry activity in the Chukchi and 
Beaufort Seas. Results of these measurements were reported in various 
90-day and comprehensive reports since 2007 (e.g., Aerts et al. 2008; 
Hauser et al. 2008; Brueggeman 2009; Ireland et al. 2009; O'Neill and 
McCrodan 2011; Chorney et al. 2011). For example, Garner and Hannay 
(2009) estimated sound pressure levels of 100 dB at distances ranging 
from approximately 1.5 to 2.3 mi (2.4 to 3.7 km) from various types of 
barges. MacDonald et al. (2008) estimated higher underwater SPLs from 
the seismic vessel Gilavar of 120 dB at approximately 13 mi (21 km) 
from the source, although the sound level was only 150 dB at 85 ft (26 
m) from the vessel. Compared to airgun pulses, underwater sound from 
vessels is generally at relatively low frequencies. However, noise from 
the vessel during geophysical soil investigation while operating the DP 
system using thrusters as well as the primary propeller(s) could 
produce noise levels higher than during normal operation of the vessel. 
Measurements of a vessel in DP mode with an active bow thruster were 
made in the Chukchi Sea in 2010 (Chorney et al. 2011). The resulting 
source level estimate was 175.9 dBrms re 1 [mu]Pa-m. Noise 
at this high level is not expected to be emitted continuously. It is 
emitted intermittently as the pitch is engaged to position the vessel.
    The primary sources of sounds from all vessel classes are propeller 
cavitation, propeller singing, and propulsion or other machinery. 
Propeller cavitation is usually the dominant noise source for vessels 
(Ross 1976). Propeller cavitation and singing are produced outside the 
hull, whereas propulsion or other machinery noise originates inside the 
hull. There are additional sounds produced by vessel activity, such as 
pumps, generators, flow noise from water passing over the hull, and 
bubbles breaking in the wake. Source levels from various vessels would 
be empirically measured before the start of marine surveys, and during 
geotechnical soil investigation while operating the DP system.

Anticipated Effects on Habitat

    The primary potential impacts to marine mammals and other marine 
species are associated with elevated sound levels produced by airguns 
and other active acoustic sources. However, other potential impacts to 
the surrounding habitat from physical disturbance are also possible.

Potential Impacts on Prey Species

    With regard to fish as a prey source for cetaceans and pinnipeds, 
fish are known to hear and react to sounds and to use sound to 
communicate (Tavolga et al. 1981) and possibly avoid predators (Wilson 
and Dill 2002). Experiments have shown that fish can sense both the 
strength and direction of sound (Hawkins 1981). Primary factors 
determining whether a fish can sense a sound signal, and potentially 
react to it, are the frequency of the signal and the strength of the 
signal in relation to the natural background noise level.
    The level of sound at which a fish will react or alter its behavior 
is usually well above the detection level. Fish have been found to 
react to sounds when the sound level increased to about 20 dB above the 
detection level of 120

[[Page 30116]]

dB (Ona 1988); however, the response threshold can depend on the time 
of year and the fish's physiological condition (Engas et al. 1993). In 
general, fish react more strongly to pulses of sound rather than a 
continuous signal (Blaxter et al. 1981), and a quicker alarm response 
is elicited when the sound signal intensity rises rapidly compared to 
sound rising more slowly to the same level.
    Investigations of fish behavior in relation to vessel noise (Olsen 
et al. 1983; Ona 1988; Ona and Godo 1990) have shown that fish react 
when the sound from the engines and propeller exceeds a certain level. 
Avoidance reactions have been observed in fish such as cod and herring 
when vessels approached close enough that received sound levels are 110 
dB to 130 dB (Nakken 1992; Olsen 1979; Ona and Godo 1990; Ona and 
Toresen 1988). However, other researchers have found that fish such as 
polar cod, herring, and capeline are often attracted to vessels 
(apparently by the noise) and swim toward the vessel (Rostad et al. 
2006). Typical sound source levels of vessel noise in the audible range 
for fish are 150 dB to 170 dB (Richardson et al. 1995).
    Some mysticetes, including bowhead whales, feed on concentrations 
of zooplankton. Some feeding bowhead whales may occur in the Alaskan 
Beaufort Sea in July and August, and others feed intermittently during 
their westward migration in September and October (Richardson and 
Thomson [eds.] 2002; Lowry et al. 2004). However, by the time most 
bowhead whales reach the Chukchi Sea (October), they will likely no 
longer be feeding, or if it occurs it will be very limited. A reaction 
by zooplankton to a seismic impulse would only be relevant to whales if 
it caused concentrations of zooplankton to scatter. Pressure changes of 
sufficient magnitude to cause that type of reaction would probably 
occur only very close to the source. Impacts on zooplankton behavior 
are predicted to be negligible, and that would translate into 
negligible impacts on feeding mysticetes. Thus, the proposed activity 
is not expected to have any habitat-related effects that could cause 
significant or long-term consequences for individual marine mammals or 
their populations.

Proposed Mitigation

    In order to issue an incidental take authorization under Section 
101(a)(5)(D) of the MMPA, NMFS must set forth the permissible methods 
of taking pursuant to such activity, and other means of effecting the 
least practicable adverse impact on such species or stock and its 
habitat, paying particular attention to rookeries, mating grounds, and 
areas of similar significance, and on the availability of such species 
or stock for taking for certain subsistence uses.
    For the proposed Statoil open water shallow hazards survey in the 
Chukchi Sea, Statoil worked with NMFS and proposed the following 
mitigation measures to minimize the potential impacts to marine mammals 
in the project vicinity as a result of the shallow hazards survey 
activities.
    As part of the application, Statoil submitted to NMFS a Marine 
Mammal Monitoring and Mitigation Program (4MP) for its open water 
shallow hazards survey in the Chukchi Sea during the 2011 open-water 
season. The objectives of the 4MP are:
     To ensure that disturbance to marine mammals and 
subsistence hunts is minimized and all permit stipulations are 
followed,
     To document the effects of the proposed survey activities 
on marine mammals, and
     To collect baseline data on the occurrence and 
distribution of marine mammals in the study area.
    The 4MP may be modified or supplemented based on comments or new 
information received from the public during the public comment period 
or from the peer review panel (see the ``Monitoring Plan Peer Review'' 
section later in this document).

Mitigation Measures Proposed in Statoil's IHA Application

    For the proposed mitigation measures, Statoil listed the following 
protocols to be implemented during its shallow hazards survey in the 
Chukchi Sea.
(1) Sound Source Measurements
    As described above, previous measurements of similar airgun arrays 
in the Chukchi Sea were used to model the distances at which received 
levels are likely to fall below 120, 160, 180, and 190 dB re 1 [mu]Pa 
(rms) from the planned airgun sources. These modeled distances will be 
used as temporary safety radii until measurements of the airgun sound 
source are conducted. The measurements will be made at the beginning of 
the field season and the measured radii used for the remainder of the 
survey period.
    The objectives of the sound source verification measurements 
planned for 2011 in the Chukchi Sea will be to measure the distances at 
which broadband received levels reach 190, 180, 170, 160, and 120 
dBrms re 1 [mu]Pa for the airgun configurations that may be 
used during the survey activities. The configurations will include at 
least the full array (4 x 10 in\3\) and the operation of a single 10 
in\3\ airgun that will be used during power downs or very shallow 
penetration surveys. The measurements of airgun sounds will be made by 
an acoustics contractor at the beginning of the survey. The distances 
to the various radii will be reported as soon as possible after 
recovery of the equipment. The primary radii of concern will be the 190 
and 180 dB safety radii for pinnipeds and cetaceans, respectively, and 
the 160 dB disturbance radii. In addition to reporting the radii of 
specific regulatory concern, nominal distances to other sound isopleths 
down to 120 dBrms will be reported in increments of 10 dB. 
Sound levels during soil investigation operations will also be 
measured. However, source levels are not expected to be strong enough 
to require mitigation actions at the 190 dB or 180 dB levels.
    Data will be previewed in the field immediately after download from 
the hydrophone instruments. An initial sound source analysis will be 
supplied to NMFS and the vessel within 120 hours of completion of the 
measurements, if possible. The report will indicate the distances to 
sound levels based on fits of empirical transmission loss formulae to 
data in the endfire and broadside directions. A more detailed report 
will be issued to NMFS as part of the 90-day report following 
completion of the acoustic program.
(2) Safety and Disturbance Zones
    Under current NMFS guidelines, ``safety radii'' for marine mammal 
exposure to impulse sources are customarily defined as the distances 
within which received sound levels are >= 180 dBrms re 1 
[mu]Pa for cetaceans and >= 190 dBrms re 1 [mu]Pa for 
pinnipeds. These safety criteria are based on an assumption that SPL 
received at levels lower than these will not injure these animals or 
impair their hearing abilities, but that at higher levels might have 
some such effects. Disturbance or behavioral effects to marine mammals 
from underwater sound may occur after exposure to sound at distances 
greater than the safety radii (Richardson et al. 1995).
    Initial safety and disturbance radii for the sound levels produced 
by the planned airgun configurations have been estimated (Table 1). 
These radii will be used for mitigation purposes until results of 
direct measurements are available early during the exploration 
activities. The proposed surveys will use an airgun source composed of 
four

[[Page 30117]]

10-in\3\ airguns (total discharge volume of 40 in\3\) and a single 10 
in\3\ airgun. Underwater sound propagation from a similar 4 x 10-in\3\ 
airgun cluster and single 10 in\3\ was measured in 2009 (Reiser et al. 
2010). Those measurements resulted in 90th percentile propagation loss 
equations of RL = 218.0-17.5LogR-0.00061R for the 4 x 10 in\3\ airgun 
cluster and RL = 204.4-16.0LogR-0.00082R for the single 10 in\3\ airgun 
(where RL = received level and R = range). The estimated distances for 
the proposed 2011 activities are based on a 25% increase over 2009 
results (Table 1).
    In addition to the site surveys, Statoil plans to use a dedicated 
vessel to conduct geotechnical soil investigations. Sounds produced by 
the vessel and soil investigation equipment are not expected to be 
above 180 dB (rms). Therefore, mitigation related to acoustic impacts 
from these activities is not expected to be necessary.
    An acoustics contractor will perform direct measurements of the 
received levels of underwater sound versus distance and direction from 
the airguns and soil investigation vessel using calibrated hydrophones. 
The acoustic data will be analyzed as quickly as reasonably practicable 
in the field and used to verify and adjust the safety distances. The 
field report will be made available to NMFS and the MMOs within 120 hrs 
of completing the measurements. The mitigation measures to be 
implemented at the 190 and 180 dB sound levels will include power downs 
and shut downs as described below.

  Table 1--Distances to Specified Received Levels Measured From a 4 x 10 in\3\ Airgun Cluster and a Single 10-
 in\3\ Airgun on the Burger Prospect in 2009 as Reported by Reiser et al. (2010). The 2011 ``Pre-SSV'' Distances
    Are a Precautionary 25% Increase Above the Reported 2009 Results and Will Be Used by MMOs for Mitigation
                                   Purposes Until an SSV Is Completed in 2011
----------------------------------------------------------------------------------------------------------------
                                                                       Distance (m)
                                         -----------------------------------------------------------------------
  Received Levels (dB re 1 [mu]Pa rms)       Airgun cluster (4 x 10 in\3\)       Single airgun (1 x 10 in\3\)
                                         -----------------------------------------------------------------------
                                            2009 Results      2011 pre-SSV      2009 Results      2011 pre-SSV
----------------------------------------------------------------------------------------------------------------
190.....................................                39                50                 8                10
180.....................................               150               190                34                45
160.....................................             1,800             2,250               570               715
120.....................................            31,000            39,000            19,000            24,000
----------------------------------------------------------------------------------------------------------------

(3) Speed and Course Alterations
    If a marine mammal is detected outside the applicable safety radius 
and, based on its position and the relative motion, is likely to enter 
the safety radius, changes of the vessel's speed and/or direct course 
will be considered if this does not compromise operational safety. For 
marine seismic surveys using large streamer arrays, course alterations 
are not typically possible. However, for the smaller airgun array and 
streamer planned during the proposed site surveys, such changes may be 
possible. After any such speed and/or course alteration is begun, the 
marine mammal activities and movements relative to the survey vessel 
will be closely monitored to ensure that the marine mammal does not 
approach within the safety radius. If the mammal appears likely to 
enter the safety radius, further mitigative actions will be taken, 
including a power down or shut down of the airgun(s).
(4) Power Downs
    A power down for immediate mitigation purposes is the immediate 
reduction in the number of operating airguns such that the radii of the 
190 dBrms and 180 dBrms zones are decreased to 
the extent that an observed marine mammal(s) are not in the applicable 
safety zone of the full array. Power downs are also used while the 
vessel turns from the end of one survey line to the start of the next. 
During a power down, one airgun (or some other number of airguns less 
than the full airgun array) continues firing. The continued operation 
of one airgun is intended to (a) alert marine mammals to the presence 
of the survey vessel in the area, and (b) retain the option of 
initiating a ramp up to full operations under poor visibility 
conditions.
    The array will be immediately powered down whenever a marine mammal 
is sighted approaching close to or within the applicable safety zone of 
the full array, but is outside the applicable safety zone of the single 
mitigation airgun. Likewise, if a mammal is already within the safety 
zone when first detected, the airguns will be powered down immediately. 
If a marine mammal is sighted within or about to enter the applicable 
safety zone of the single mitigation airgun, it too will be shut down 
(see following section).
    Following a power down, operation of the full airgun array will not 
resume until the marine mammal has cleared the safety zone. The animal 
will be considered to have cleared the safety zone if it:
     Is visually observed to have left the safety zone of the 
full array, or
     Has not been seen within the zone for 15 min in the case 
of pinnipeds or small odontocetes, or
     Has not been seen within the zone for 30 min in the case 
of mysticetes or large odontocetes.
(5) Shut Downs
    The operating airgun(s) will be shut down completely if a marine 
mammal approaches or enters the then-applicable safety radius and a 
power down is not practical or adequate to reduce exposure to less than 
190 or 180 dBrms, as appropriate. In most cases, this means 
the mitigation airgun will be shut down completely if a marine mammal 
approaches or enters the estimated safety radius around the single 10 
in\3\ airgun while it is operating during a power down. Airgun activity 
will not resume until the marine mammal has cleared the safety radius. 
The animal will be considered to have cleared the safety radius as 
described above under power down procedures.
    A shut down of the borehole drilling equipment may be requested by 
MMOs if an animal is sighted approaching the vessel close enough to 
potentially interact with and be harmed by the soil investigation 
operation.
(6) Ramp Ups
    A ramp up of an airgun array provides a gradual increase in sound 
levels, and involves a step-wise increase in the number and total 
volume of airguns firing until the full volume is achieved. The purpose 
of a ramp up (or ``soft start'') is to ``warn'' cetaceans and pinnipeds 
in the vicinity of the airguns and to provide the time for them to 
leave the area and thus avoid any

[[Page 30118]]

potential injury or impairment of their hearing abilities.
    During the proposed site survey program, the seismic operator will 
ramp up the airgun cluster slowly. Full ramp ups (i.e., from a cold 
start after a shut down, when no airguns have been firing) will begin 
by firing a single airgun in the array. The minimum duration of a shut-
down period, i.e., without air guns firing, which must be followed by a 
ramp up is typically the amount of time it would take the source vessel 
to cover the 180-dB safety radius. Given the small size of the planned 
airgun array, it is estimated that period to be about 1-2 minutes based 
on the modeling results described above and a survey speed of 4 kts.
    A full ramp up, after a shut down, will not begin until there has 
been a minimum of 30 minutes of observation of the safety zone by MMOs 
to assure that no marine mammals are present. The entire safety zone 
must be visible during the 30-minute lead-in to a full ramp up. If the 
entire safety zone is not visible, then ramp up from a cold start 
cannot begin. If a marine mammal(s) is sighted within the safety zone 
during the 30-minute watch prior to ramp up, ramp up will be delayed 
until the marine mammal(s) is sighted outside of the safety zone or the 
animal(s) is not sighted for at least 15-30 minutes: 15 minutes for 
small odontocetes and pinnipeds, or 30 minutes for baleen whales and 
large odontocetes.
    During turns or brief transits between survey transects, one airgun 
will continue operating. The ramp-up procedure will still be followed 
when increasing the source levels from one airgun to the full 4-airgun 
cluster. However, keeping one airgun firing will avoid the prohibition 
of a cold start during darkness or other periods of poor visibility. 
Through use of this approach, survey operations can resume upon entry 
to a new transect without the 30-minute watch period of the full safety 
radius required for a cold start. MMOs will be on duty whenever the 
airguns are firing during daylight, and during the 30-min periods prior 
to ramp-ups as well as during ramp-ups. Daylight will occur for 24 h/
day until mid-August, so until that date MMOs will automatically be 
observing during the 30-minute period preceding a ramp up. Later in the 
season, MMOs will be called to duty at night to observe prior to and 
during any ramp ups. The survey operator and MMOs will maintain records 
of the times when ramp-ups start, and when the airgun arrays reach full 
power.

Additional Mitigation Measures Proposed by NMFS

    Besides Statoil's proposed mitigation measures discussed above, 
NMFS proposes the following additional protective measures to address 
some uncertainties regarding the impacts of bowhead cow-calf pairs and 
aggregations of whales from shallow hazards surveys. Specifically, NMFS 
proposes that
     A 160-dB vessel monitoring zone for large whales will be 
established and monitored in the Chukchi Sea during all shallow hazards 
surveys. Whenever an aggregation of bowhead whales or gray whales (12 
or more whales of any age/sex class that appear to be engaged in a non-
migratory, significant biological behavior (e.g., feeding, 
socializing)) are observed during a vessel monitoring program within 
the 160-dB safety zone around the survey operations, the survey 
activity will not commence or will shut down, until they are no longer 
present within the 160-dB safety zone of shallow hazards surveying 
operations.
    Furthermore, NMFS proposes the following measures be included in 
the IHA, if issued, in order to ensure the least practicable impact on 
the affected species or stocks:
    (1) All vessels should reduce speed when within 300 yards (274 m) 
of whales, and those vessels capable of steering around such groups 
should do so. Vessels may not be operated in such a way as to separate 
members of a group of whales from other members of the group;
    (2) Avoid multiple changes in direction and speed when within 300 
yards (274 m) of whales; and
    (3) When weather conditions require, such as when visibility drops, 
support vessels must adjust speed (increase or decrease) and direction 
accordingly to avoid the likelihood of injury to whales.

Mitigation Conclusions

    NMFS has carefully evaluated the applicant's proposed mitigation 
measures and considered a range of other measures in the context of 
ensuring that NMFS prescribes the means of effecting the least 
practicable impact on the affected marine mammal species and stocks and 
their habitat. Our evaluation of potential measures included 
consideration of the following factors in relation to one another:
     The manner in which, and the degree to which, the 
successful implementation of the measure is expected to minimize 
adverse impacts to marine mammals;
     The proven or likely efficacy of the specific measure to 
minimize adverse impacts as planned; and
     The practicability of the measure for applicant 
implementation.
    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means of 
effecting the least practicable impact on marine mammal species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance.

Proposed Monitoring and Reporting

    In order to issue an ITA for an activity, Section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth ``requirements pertaining to 
the monitoring and reporting of such taking''. The MMPA implementing 
regulations at 50 CFR 216.104 (a)(13) indicate that requests for ITAs 
must include the suggested means of accomplishing the necessary 
monitoring and reporting that will result in increased knowledge of the 
species and of the level of taking or impacts on populations of marine 
mammals that are expected to be present in the proposed action area.

Monitoring Measures Proposed in Statoil's IHA Application

    The monitoring plan proposed by Statoil can be found in the 4MP. 
The plan may be modified or supplemented based on comments or new 
information received from the public during the public comment period 
or from the peer review panel (see the ``Monitoring Plan Peer Review'' 
section later in this document). A summary of the primary components of 
the plan follows.
(1) Vessel-Based MMOs
    Vessel-based monitoring for marine mammals will be done by trained 
MMOs throughout the period of marine survey activities. MMOs will 
monitor the occurrence and behavior of marine mammals near the survey 
vessel during all daylight periods during operation and during most 
daylight periods when airgun operations are not occurring. MMO duties 
will include watching for and identifying marine mammals, recording 
their numbers, distances, and reactions to the survey operations, and 
documenting ``take by harassment'' as defined by NMFS.
    A sufficient number of MMOs will be required onboard the survey 
vessel to meet the following criteria: (1) 100% monitoring coverage 
during all periods of survey operations in daylight; (2) maximum of 4 
consecutive hours on watch per MMO; and (3) maximum of

[[Page 30119]]

12 hours of watch time per day per MMO.
    MMO teams will consist of Inupiat observers and experienced field 
biologists. An experienced field crew leader will supervise the MMO 
team onboard the survey vessel. The total number of MMOs may decrease 
later in the season as the duration of daylight decreases. Statoil 
currently plans to have 5 MMOs aboard the site survey vessel and 3 MMOs 
aboard the soil investigation vessel, with the potential of reducing 
the number of MMOs later in the season as daylight periods decrease in 
length.
    Crew leaders and most other biologists serving as observers in 2011 
will be individuals with experience as observers during recent seismic 
or shallow hazards monitoring projects in Alaska, the Canadian 
Beaufort, or other offshore areas in recent years.
    Observers will complete a two or three-day training session on 
marine mammal monitoring, to be conducted shortly before the 
anticipated start of the 2011 open-water season. The training 
session(s) will be conducted by qualified marine mammalogists with 
extensive crew-leader experience during previous vessel-based 
monitoring programs. A marine mammal observers' handbook, adapted for 
the specifics of the planned survey program will be reviewed as part of 
the training.
    Primary objectives of the training include:
     Review of the marine mammal monitoring plan for this 
project, including any amendments specified by NMFS in the IHA (if 
issued), by USFWS or Bureau of Ocean Energy Management, Regulation and 
Enforcement (BOEMRE), or by other agreements in which Statoil may elect 
to participate;
     Review of marine mammal sighting, identification, and 
distance estimation methods;
     Review of operation of specialized equipment (reticle 
binoculars, night vision devices, and GPS system);
     Review of, and classroom practice with, data recording and 
data entry systems, including procedures for recording data on marine 
mammal sightings, monitoring operations, environmental conditions, and 
entry error control. These procedures will be implemented through use 
of a customized computer database and laptop computers;
     Review of the specific tasks of the Inupiat Communicator.
    The observer(s) will watch for marine mammals from the best 
available vantage point on the survey vessels, typically the bridge. 
The observer(s) will scan systematically with the unaided eye and 7x50 
reticle binoculars, supplemented with 20x60 image-stabilized Zeiss 
Binoculars or Fujinon 25x150 ``Big-eye'' binoculars, and night-vision 
equipment when needed (see below). Personnel on the bridge will assist 
the marine mammal observer(s) in watching for marine mammals.
    Information to be recorded by marine mammal observers will include 
the same types of information that were recorded during recent 
monitoring programs associated with Industry activity in the Arctic 
(e.g., Ireland et al. 2009). When a mammal sighting is made, the 
following information about the sighting will be recorded:
    (A) Species, group size, age/size/sex categories (if determinable), 
behavior when first sighted and after initial sighting, heading (if 
consistent), bearing and distance from the MMO, apparent reaction to 
activities (e.g., none, avoidance, approach, paralleling, etc.), 
closest point of approach, and behavioral pace;
    (B) Time, location, speed, activity of the vessel, sea state, ice 
cover, visibility, and sun glare; and
    (C) The positions of other vessel(s) in the vicinity of the MMO 
location.
    The ship's position, speed of support vessels, and water 
temperature, water depth, sea state, ice cover, visibility, and sun 
glare will also be recorded at the start and end of each observation 
watch, every 30 minutes during a watch, and whenever there is a change 
in any of those variables.

Monitoring At Night and In Poor Visibility

    Night-vision equipment (Generation 3 binocular image intensifiers, 
or equivalent units) will be available for use when/if needed. Past 
experience with night-vision devices (NVDs) in the Beaufort and Chukchi 
seas and elsewhere has indicated that NVDs are not nearly as effective 
as visual observation during daylight hours (e.g., Harris et al. 1997, 
1998; Moulton and Lawson 2002).
(2) Acoustic Monitoring

Sound Source Measurements

    As described above, previous measurements of airguns in the Chukchi 
Sea were used to estimate the distances at which received levels are 
likely to fall below 120, 160, 180, and 190 dBrms from the 
planned airgun sources. These modeled distances will be used as 
temporary safety radii until measurements of the airgun sound source 
are conducted. The measurements will be made at the beginning of the 
field season and the measured radii used for the remainder of the 
survey period. An acoustics contractor will use their equipment to 
record and analyze the underwater sounds and write the summary reports 
as described below.
    The objectives of the sound source verification measurements 
planned for 2011 in the Chukchi Sea will be (1) to measure the 
distances at which broadband received levels reach 190, 180, 170, 160, 
and 120 dBrms re 1 [micro]Pa for the airgun configurations 
that may be used during the survey activities. The configurations will 
include at least the full array (4x10 in\3\) and the operation of a 
single 10 in\3\ airgun that will be used during power downs or very 
shallow penetration surveys.

2011 Joint Environmental Studies Program

    Statoil, Shell Offshore, Inc. (Shell), and ConocoPhillips Alaska 
Inc. (CPAI) are working on plans to once again jointly fund an 
extensive environmental studies program in the Chukchi Sea. This 
program is expected to be coordinated by Olgoonik-Fairweather LLC 
(OFJV) during the 2011 open water season. The environmental studies 
program is not part of the Statoil site survey and soil investigations 
program, but acoustic monitoring equipment is planned to be deployed on 
and near Statoil leases and will therefore collect additional data on 
the sounds produced by the 2011 activities. The program components 
include:
     Acoustics Monitoring
     Fisheries Ecology
     Benthic Ecology
     Plankton Ecology
     Marine Mammal Surveys
     Seabird Surveys, and
     Physical Oceanography.
    The planned 2011 program will continue the acoustic monitoring 
programs carried out in 2006-2010. A similar number of acoustic 
recorders as deployed in past years will be distributed broadly across 
the Chukchi lease area and nearshore environment. In past years, 
clusters of recorders designed to localize marine mammal calls 
originating within or nearby the clusters have been deployed on each of 
the companies' prospects: Amundsen (Statoil), Burger (Shell), and 
Klondike (CPAI). This year, recorders from the clusters are planned to 
be relocated in a broader deployment on and around Hanna Shoal.
    The recorders will be deployed in late July or mid-August and will 
be retrieved in early to mid-October, depending on ice conditions. The 
recorders will be AMAR and AURAL model acoustic

[[Page 30120]]

buoys set to record at 16 kHz sample rate. These are the same recorder 
models and same sample rates that have been used for this program from 
2006-2010. The broad area arrays are designed to capture both general 
background soundscape data, industrial sounds and marine mammal call 
data across the lease area. From previous deployments of these 
recordings we have been able to gain insight into large-scale 
distributions of marine mammals, identification of marine mammal 
species present, movement and migration patterns, and general abundance 
data.

Monitoring Plan Peer Review

    The MMPA requires that monitoring plans be independently peer 
reviewed ``where the proposed activity may affect the availability of a 
species or stock for taking for subsistence uses'' (16 U.S.C. 
1371(a)(5)(D)(ii)(III)). Regarding this requirement, NMFS' implementing 
regulations state, ``Upon receipt of a complete monitoring plan, and at 
its discretion, [NMFS] will either submit the plan to members of a peer 
review panel for review or within 60 days of receipt of the proposed 
monitoring plan, schedule a workshop to review the plan'' (50 CFR 
216.108(d)).
    NMFS convened an independent peer review panel to review Statoil's 
mitigation and monitoring plan in its IHA application for taking marine 
mammals incidental to the proposed shallow hazards survey in the 
Chukchi Sea, during 2011. The panel met and reviewed the plan in early 
March 2011, and provided comments to NMFS in April 2011. NMFS is 
currently reviewing the panel report and will consider all 
recommendations made by the panel, incorporate appropriate changes into 
the monitoring requirements of the IHA (if issued) and publish the 
panel's findings and recommendations in the final IHA notice of 
issuance or denial document.

Reporting Measures

(1) SSV Report
    A report on the preliminary results of the acoustic verification 
measurements, including as a minimum the measured 190-, 180-, 160-, and 
120-dBrms re 1 [mu]Pa radii of the source vessel(s) and the 
support vessels, will be submitted within 120 hr after collection and 
analysis of those measurements at the start of the field season. This 
report will specify the distances of the safety zones that were adopted 
for the marine survey activities.
(2) Field Reports
    Statoil states that throughout the survey program, the observers 
will prepare a report each day or at such other interval as the IHA (if 
issued), or Statoil may require, summarizing the recent results of the 
monitoring program. The field reports will summarize the species and 
numbers of marine mammals sighted. These reports will be provided to 
NMFS and to the survey operators.
(3) Technical Reports
    The results of Statoil's 2011 vessel-based monitoring, including 
estimates of ``take'' by harassment, will be presented in the ``90-
day'' and Final Technical reports. Statoil proposes that the Technical 
Reports will include:
    (a) Summaries of monitoring effort (e.g., total hours, total 
distances, and marine mammal distribution through the study period, 
accounting for sea state and other factors affecting visibility and 
detectability of marine mammals);
    (b) Analyses of the effects of various factors influencing 
detectability of marine mammals (e.g., sea state, number of observers, 
and fog/glare);
    (c) Species composition, occurrence, and distribution of marine 
mammal sightings, including date, water depth, numbers, age/size/gender 
categories (if determinable), group sizes, and ice cover;
    (d) Analyses of the effects of survey operations;
     Sighting rates of marine mammals during periods with and 
without airgun activities (and other variables that could affect 
detectability), such as:
     Initial sighting distances versus airgun activity state;
     Closest point of approach versus airgun activity state;
     Observed behaviors and types of movements versus airgun 
activity state;
     Numbers of sightings/individuals seen versus airgun 
activity state;
     Distribution around the survey vessel versus airgun 
activity state; and
     Estimates of take by harassment.
(4) Comprehensive Report
    Following the 2011 open-water season a comprehensive report 
describing the vessel-based and acoustic monitoring programs will be 
prepared. The comprehensive report will describe the methods, results, 
conclusions and limitations of each of the individual data sets in 
detail. The report will also integrate (to the extent possible) the 
studies into a broad based assessment of industry activities, and other 
activities that occur in the Beaufort and/or Chukchi seas, and their 
impacts on marine mammals during 2011. The report will help to 
establish long-term data sets that can assist with the evaluation of 
changes in the Chukchi and Beaufort sea ecosystems. The report will 
attempt to provide a regional synthesis of available data on industry 
activity in offshore areas of northern Alaska that may influence marine 
mammal density, distribution and behavior.
(5) Notification of Injured or Dead Marine Mammals
    In addition to the reporting measures proposed by Statoil, NMFS 
will require that Statoil notify NMFS' Office of Protected Resources 
and NMFS' Stranding Network within 48 hours of sighting an injured or 
dead marine mammal in the vicinity of marine survey operations. Statoil 
shall provide NMFS with the species or description of the animal(s), 
the condition of the animal(s) (including carcass condition if the 
animal is dead), location, time of first discovery, observed behaviors 
(if alive), and photo or video (if available).
    In the event that an injured or dead marine mammal is found by 
Statoil that is not in the vicinity of the proposed open water marine 
survey program, Statoil will report the same information as listed 
above as soon as operationally feasible to NMFS.

Estimated Take by Incidental Harassment

    Except with respect to certain activities not pertinent here, the 
MMPA defines ``harassment'' as: Any act of pursuit, torment, or 
annoyance which (i) has the potential to injure a marine mammal or 
marine mammal stock in the wild [Level A harassment]; or (ii) has the 
potential to disturb a marine mammal or marine mammal stock in the wild 
by causing disruption of behavioral patterns, including, but not 
limited to, migration, breathing, nursing, breeding, feeding, or 
sheltering [Level B harassment]. Only take by Level B behavioral 
harassment is anticipated as a result of the proposed open water marine 
survey program. Anticipated impacts to marine mammals are associated 
with noise propagation from the survey airgun(s) used in the shallow 
hazards survey.
    The full suite of potential impacts to marine mammals was described 
in detail in the ``Potential Effects of the Specified Activity on 
Marine Mammals'' section found earlier in this document. The potential 
effects of sound from the proposed open water marine survey programs 
might include one or more of the following: Tolerance; masking of

[[Page 30121]]

natural sounds; behavioral disturbance; non-auditory physical effects; 
and, at least in theory, temporary or permanent hearing impairment 
(Richardson et al. 1995). As discussed earlier in this document, the 
most common impact will likely be from behavioral disturbance, 
including avoidance of the ensonified area or changes in speed, 
direction, and/or diving profile of the animal. For reasons discussed 
previously in this document, hearing impairment (TTS and PTS) are 
highly unlikely to occur based on the proposed mitigation and 
monitoring measures that would preclude marine mammals being exposed to 
noise levels high enough to cause hearing impairment.
    For impulse sounds, such as those produced by airgun(s) used in the 
seismic survey, NMFS uses the 160 dBrms re 1 [mu]Pa isopleth 
to indicate the onset of Level B harassment. For non-impulse sounds, 
such as noise generated during the geotechnical soil investigation that 
involves drilling bore holes and running DP thruster of the vessel, 
NMFS uses the 120 dBrms re 1 [mu]Pa isopleth to indicate the 
onset of Level B harassment. Statoil provided calculations for the 160- 
and 120-dB isopleths produced by these activities and then used those 
isopleths to estimate takes by harassment. NMFS used the calculations 
to make the necessary MMPA preliminary findings. Statoil provided a 
full description of the methodology used to estimate takes by 
harassment in its IHA application (see ADDRESSES), which is also 
provided in the following sections.
    Statoil has requested an authorization to take 13 marine mammal 
species by Level B harassment. These 13 marine mammal species are: 
Beluga whale (Delphinapterus leucas), narwhal (Monodon monoceros), 
killer whale (Orcinus orca), harbor porpoise (Phocoena phocoena), 
bowhead whale (Balaena mysticetus), gray whale (Eschrichtius robustus), 
humpback whale (Megaptera novaeangliae), minke whale (Balaenoptera 
acutorostrata), fin whale (B. physalus), bearded seal (Erignathus 
barbatus), ringed seal (Phoca hispida), spotted seal (P. largha), and 
ribbon seal (Histriophoca fasciata).

Basis for Estimating ``Take by Harassment''

    As stated previously, it is current NMFS policy to estimate take by 
Level B harassment for impulse sounds at a received level of 160 
dBrms re 1[mu]Pa. However, not all animals react to sounds 
at this low level, and many will not show strong reactions (and in some 
cases any reaction) until sounds are much stronger. Southall et al. 
(2007) provide a severity scale for ranking observed behavioral 
responses of both free-ranging marine mammals and laboratory subjects 
to various types of anthropogenic sound (see Table 4 in Southall et al. 
(2007)). Tables 7, 9, and 11 in Southall et al. (2007) outline the 
numbers of low-frequency cetaceans, mid-frequency cetaceans, and 
pinnipeds in water, respectively, reported as having behavioral 
responses to multi-pulses in 10-dB received level increments. These 
tables illustrate that for the studies summarized the more severe 
reactions did not occur until sounds were much higher than 160 
dBrms re 1[mu]Pa.
    As described earlier in the document, a 4x10 in\3\ airgun cluster 
will be used to obtain geological data during the site surveys. A 
similar airgun cluster was measured by Shell in 2009 during shallow 
hazards surveys on their nearby Burger prospect (Reiser et al. 2010). 
The measurements resulted in 90th percentile propagation loss equations 
of RL = 218.-17.5LogR-0.00061R for a 4x10 in\3\ airgun cluster and RL = 
204.4-16.0LogR-0.00082R for a single 10 in\3\ airgun (where RL = 
received level and R = range). For use in estimating potential 
harassment takes in this application, as well as for mitigation radii 
to be implemented by MMOs prior to SSV measurements, ranges to 
threshold levels from the 2009 measurements were increased by 25% as a 
precautionary approach (Table 1). The >=160 dB distance is therefore 
estimated to be 2.25 km from the source. Adding a 2.25 km perimeter to 
the two site survey areas results in an estimated area of 1,037 km\2\ 
being exposed to >=160 dB.
    Geotechnical soil investigations on the Statoil leases and leases 
jointly owned with CPAI will involve completing 3-4 boreholes at up to 
8 total prospective drilling locations for an expected maximum of 29 
boreholes. The 3-4 boreholes completed at each drilling location will 
be positioned in a square or triangle formation, roughly 100 m on each 
side. As described earlier, the sounds produced by soil investigation 
equipment are estimated to fall below 120 dB at a distance of 7.5 km. 
Buffering 4 core sites spaced 100 m apart with the 7.5 km 120 dB 
distance results in a total area of 180 km\2\. The total area exposed 
to sounds >=120 dB by soil investigations at the 8 prospective drilling 
locations will therefore be 1,440 km\2\.
    The following subsections describe the estimated densities of 
marine mammals that may occur in the areas where activities are 
planned, and areas of water that may be ensonified by pulsed sounds to 
>= 160 dB or non-pulsed sounds to >= 120 dB.
    Marine mammal densities near the planned activities in the Chukchi 
Sea are likely to vary by season, and habitat. Therefore, densities 
have been derived for two time periods, the summer period, including 
July and August, and the fall period, including September and October. 
Animal densities encountered in the Chukchi Sea during both of these 
time periods will further depend on whether they are occurring in open 
water or near the ice margin. Vessel and equipment limitations will 
result in very little activity occurring in or near sea ice, however, 
if ice is present near the areas of activity some sounds produced by 
the activities may remain above disturbance threshold levels in ice 
margin habitats. Therefore, open water densities have been used to 
estimate potential ``take by harassment'' in 90% of the area expected 
to be ensonified above disturbance thresholds while ice margin 
densities have been used in the remaining 10% of the ensonified area.
    Detectability bias [f(0)] is associated with diminishing 
sightability with increasing lateral distance from the trackline. 
Availability bias [g(0)] refers to the fact that there is < 100% 
probability of sighting an animal that is present on the survey 
trackline. Some sources of densities used below included these 
correction factors in their reported densities. In other cases the best 
available correction factors were applied to reported results when they 
had not been included in the reported analyses (e.g. Moore et al. 
2000).
(1) Cetaceans
    Eight species of cetaceans are known to occur in the Chukchi Sea 
area of the proposed Statoil project. Only four of these (bowhead, 
beluga, and gray whales, and harbor porpoise) are likely to be 
encountered during the proposed survey activities. Three of the eight 
species (bowhead, fin, and humpback whales) are listed as endangered 
under the ESA. Of these, only the bowhead is likely to be found within 
the survey area.
    Beluga Whales--Summer densities of belugas in offshore waters of 
the Chukchi Sea are expected to be low, with higher densities in ice-
margin and nearshore areas. Aerial surveys have recorded few belugas in 
the offshore Chukchi Sea during the summer months (Moore et al. 2000). 
Aerial surveys of the Chukchi Sea in 2008-2009 flown by the NMML as 
part of the Chukchi Offshore Monitoring in Drilling Area project 
(COMIDA) have only reported 5 beluga

[[Page 30122]]

sightings during > 14,000 km of on-transect effort, only 2 of which 
were offshore (COMIDA 2009). One of the three nearshore sightings was 
of a large group (~275 individuals on July 12, 2009) of migrating 
belugas along the coastline just north of Peard Bay. Additionally, only 
one beluga sighting was recorded during > 61,000 km of visual effort 
during good visibility conditions from industry vessels operating 
largely in offshore areas of the Chukchi Sea in September-October of 
2006-2008 (Haley et al. 2010). If belugas are present during the 
summer, they are more likely to occur in or near the ice edge or close 
to shore during their northward migration. Expected densities have 
previously been calculated from data in Moore et al. (2000). However, 
more recent data from COMIDA aerial surveys during 2008-2010 are now 
available. Effort and sightings reported by Clarke and Ferguson (in 
prep.) were used to calculate the average open-water density estimate. 
Clarke and Ferguson (in prep.) reported two on-transect beluga 
sightings (5 individuals) during 11,985 km of on-transect effort in 
waters 36-50 m deep in the Chukchi Sea during July and August. The mean 
group size of these two sightings is 2.5 animals. A f(0) value of 2.841 
and g(0) value of 0.58 from Harwood et al. (1996) were also used in the 
density calculation. Specific data on the relative abundance of beluga 
whales in open-water versus ice-margin habitats during the summer in 
the Chukchi Sea are not available. However, belugas are commonly 
associated with ice, so an inflation factor of 4 was used to estimate 
the average ice-margin density from the open-water density. Very low 
densities observed from vessels operating in the Chukchi Sea during 
non-seismic periods and locations in July-August of 2006-2008 (0.0-
0.0001/km\2\; Haley et al. 2010) also suggest the number of beluga 
whales likely to be present near the planned activities will not be 
large (Table 2).
    In the fall, beluga whale densities in the Chukchi Sea are expected 
to be somewhat higher than in the summer because individuals of the 
eastern Chukchi Sea stock and the Beaufort Sea stock will be migrating 
south to their wintering grounds in the Bering Sea (Allen and Angliss 
2010). However, there were no beluga sightings reported during > 18,000 
km of vessel based effort in good visibility conditions during 2006-
2008 industry operations in the Chukchi Sea (Haley et al. 2010). 
Densities derived from survey results in the northern Chukchi Sea in 
Clarke and Ferguson (in prep.) were used as the average density for 
open-water fall season estimates (see Table 3). Clarke and Ferguson (in 
prep.) reported 3 beluga sightings (6 individuals) during 10,036 km of 
on-transect effort in water depths 36-50 m. The mean group size of 
those three sightings is 2 animals. A f(0) value of 2.841 and g(0) 
value of 0.58 from Harwood et al. (1996) were used in the calculation. 
Moore et al. (2000) reported lower than expected beluga sighting rates 
in open-water during fall surveys in the Beaufort and Chukchi seas, so 
an inflation value of 4 was used to estimate the average ice-margin 
density from the open-water density. Based on the lack of any beluga 
sightings from vessels operating in the Chukchi Sea during non-seismic 
periods and locations in September-October of 2006-2008 (Haley et al. 
2010), the relative low densities shown in Table 3 are consistent with 
what is likely to be observed from vessels during the planned 
operations.

   Table 2--Expected Densities of Cetaceans and Seals in Areas of the
 Chukchi Sea, Alaska, During the Planned Summer (July-August) Period of
                   the Shallow Hazards Survey Program
------------------------------------------------------------------------
                                         Open water        Ice margin
                                     -----------------------------------
               Species                 Average density   Average density
                                         (/       (/
                                           km\2\)            km\2\)
------------------------------------------------------------------------
Beluga whale........................            0.0010            0.0040
Narwhal.............................            0.0000            0.0000
Killer whale........................            0.0001            0.0001
Harbor porpoise.....................            0.0011            0.0011
Bowhead whale.......................            0.0013            0.0013
Fin whale...........................            0.0001            0.0001
Gray whale..........................            0.0258            0.0258
Humpback whale......................            0.0001            0.0001
Minke whale.........................            0.0001            0.0001
Bearded seal........................            0.0107            0.0142
Ribbon seal.........................            0.0005            0.0005
Ringed seal.........................            0.3668            0.4891
Spotted seal........................            0.0073            0.0098
------------------------------------------------------------------------


   Table 3--Expected Densities of Cetaceans and Seals in Areas of the
 Chukchi Sea, Alaska, During the Planned Fall (September-October) Period
                  of the Shallow Hazards Survey Program
------------------------------------------------------------------------
                                         Open water        Ice margin
                                     -----------------------------------
               Species                 Average density   Average density
                                         (/       (/
                                           km\2\)            km\2\)
------------------------------------------------------------------------
Beluga whale........................            0.0015            0.0060
Narwhal.............................            0.0000            0.0000
Killer whale........................            0.0001            0.0001
Harbor porpoise.....................            0.0001            0.0001
Bowhead whale.......................            0.0219            0.0438
Fin whale...........................            0.0001            0.0001
Gray whale..........................            0.0080            0.0080
Humpback whale......................            0.0001            0.0001
Minke whale.........................            0.0001            0.0001
Bearded seal........................            0.0107            0.0142

[[Page 30123]]

 
Ribbon seal.........................            0.0005            0.0005
Ringed seal.........................            0.2458            0.3277
Spotted seal........................            0.0049            0.0065
------------------------------------------------------------------------

    Bowhead Whales--By July, most bowhead whales are northeast of the 
Chukchi Sea, within or migrating toward their summer feeding grounds in 
the eastern Beaufort Sea. No bowheads were reported during 10,684 km of 
on-transect effort in the Chukchi Sea by Moore et al. (2000). Aerial 
surveys in 2008-2010 by the NMML as part of the COMIDA project reported 
six sightings during 25,781 km of on-transect effort (Clarke and 
Ferguson 2011). Two of the six sightings were in waters <= 35 m deep 
and the remaining four sightings were in waters 51-200 m deep. Bowhead 
whales were also rarely sighted in July-August of 2006-2008 during 
aerial surveys of the Chukchi Sea coast (Thomas et al. 2010). This is 
consistent with movements of tagged whales (ADFG 2010) all of which 
moved through the Chukchi Sea by early May 2009, and tended to travel 
relatively close to shore, especially in the northern Chukchi Sea. The 
estimate of summer bowhead whale density in the Chukchi Sea was 
calculated by assuming there was one bowhead sighting during the 11,985 
km of survey effort in waters 36-50 m deep in the Chukchi Sea during 
July-August reported in Clarke and Ferguson (in prep.), although no 
bowheads were actually observed during those surveys. The mean group 
size from September-October sightings reported in Clarke and Ferguson 
(in prep.) is 1.1, and this was also used in the calculation of summer 
densities. The group size value, along with a f(0) value of 2 and a 
g(0) value of 0.07, both from Thomas et al. (2002) were used to 
estimate a summer density of bowhead whales (Table 2). Bowheads are not 
expected to be encountered in higher densities near ice in the summer 
(Moore et al. 2000), so the same density estimates are used for open-
water and ice-margin habitats. Densities from vessel based surveys in 
the Chukchi Sea during non-seismic periods and locations in July-August 
of 2006-2008 (Haley et al. 2010) ranged from 0.0001-0.0007/km\2\ with a 
maximum 95 percent confidence interval (CI) of 0.0029/km\2\. This 
suggests the densities used in the calculations and shown in Table 3 
are somewhat higher than are likely to be observed from vessels near 
the area of planned operations.
    During the fall, bowhead whales that summered in the Beaufort Sea 
and Amundsen Gulf migrate west and south to their wintering grounds in 
the Bering Sea, making it more likely that bowheads will be encountered 
in the Chukchi Sea at this time of year. Moore et al. (2000; Table 8) 
reported 34 bowhead sightings during 44,354 km of on-transect survey 
effort in the Chukchi Sea during September-October. Thomas et al. 
(2010) also reported increased sightings on coastal surveys of the 
Chukchi Sea during September and October of 2006-2008. GPS tagging of 
bowheads appear to show that migration routes through the Chukchi Sea 
are more variable than through the Beaufort Sea (Quakenbush et al. 
2010). Some of the routes taken by bowheads remain well north of the 
planned activities while others have passed near to or through the 
area. Kernel densities estimated from GPS locations of whales suggest 
that bowheads do not spend much time (e.g., feeding or resting) in the 
north-central Chukchi Sea near the area of planned activities 
(Quakenbush et al. 2010). Clarke and Ferguson (in prep.) reported 14 
sightings (15 individuals) during 10,036 km of on transect aerial 
survey effort in 2008-2010. The mean group size from those sightings is 
1.1. The same f(0) and g(0) values that were used for the summer 
estimates above were used for the fall estimates (Table 3). Moore et 
al. (2000) found that Bowheads were detected more often than expected 
in association with ice in the Chukchi Sea in September-October, so a 
density of twice the average open-water density was used as the average 
ice-margin density (Table 3). Densities from vessel based surveys in 
the Chukchi Sea during non-seismic periods and locations in September-
October of 2006-2008 (Haley et al. 2010) ranged from 0.0003/km\2\ to 
0.0044/km\2\ with a maximum 95 percent CI of 0.0419 km\2\. This 
suggests the densities used in the calculations and shown in Table 3 
are somewhat higher than are likely to be observed from vessels near 
the area of planned operations.
    Gray Whales--Gray whale densities are expected to be much higher in 
the summer months than during the fall. Moore et al. (2000) found the 
distribution of gray whales in the planned operational area was 
scattered and generally limited to nearshore areas where most whales 
were observed in water less than 35 m deep. Thomas et al. (2010) also 
reported substantial declines in the sighting rates of gray whales in 
the fall. The average open-water summer density (Table 2) was 
calculated from effort and sightings reported by Clarke and Ferguson 
(in prep.) for water depths 36-50 m including 54 sightings (73 
individuals) during 11,985 km of on-transect effort. The average group 
size of those sightings is 1.35 animals. Correction factors f(0) = 2.49 
(Forney and Barlow 1998) and g(0) = 0.30 (Forney and Barlow 1998; 
Mallonee 1991) were also used in the density calculation. Gray whales 
are not commonly associated with sea ice, but may be present near it, 
so the same densities were used for ice-margin habitat as were derived 
for open-water habitat during both seasons. Densities from vessel based 
surveys in the Chukchi Sea during non-seismic periods and locations in 
July-August of 2006-2008 (Haley et al. 2010) ranged from 0.0021/km\2\ 
to 0.0080/km\2\ with a maximum 95 percent CI of 0.0336 km\2\.
    In the fall, gray whales may be dispersed more widely through the 
northern Chukchi Sea (Moore et al. 2000), but overall densities are 
likely to be decreasing as the whales begin migrating south. A density 
calculated from effort and sightings (15 sightings [19 individuals] 
during 10,036 km of on-transect effort) in water 36-50 m deep during 
September-October reported by Clarke and Ferguson (in prep.) was used 
as the average estimate for the Chukchi Sea during the fall period 
(Table 3). The corresponding group size value of 1.26, along with the 
same f(0) and g(0) values described above were also used in the 
calculation. Densities from vessel based surveys in the Chukchi Sea 
during non-seismic periods and locations in July-

[[Page 30124]]

August of 2006-2008 (Haley et al. 2010) ranged from 0.0026/km\2\ to 
0.0042/km\2\ with a maximum 95 percent CI of 0.0277 km\2\.
    Harbor Porpoise--Harbor Porpoise densities were estimated from 
industry data collected during 2006-2008 activities in the Chukchi Sea. 
Prior to 2006, no reliable estimates were available for the Chukchi Sea 
and harbor porpoise presence was expected to be very low and limited to 
nearshore regions. Observers on industry vessels in 2006-2008, however, 
recorded sightings throughout the Chukchi Sea during the summer and 
early fall months. Density estimates from 2006-2008 observations during 
non-seismic periods and locations in July-August ranged from 0.0008/
km\2\ to 0.0015/km\2\ with a maximum 95 percent CI of 0.0079/km\2\ 
(Haley et al. 2010). The average of those three years (0.0011/km\2\) 
was used as the average open-water density estimate while the high 
value (0.0015/km\2\) was used as the maximum estimate (Table 2). Harbor 
porpoise are not expected to be present in higher numbers near ice, so 
the open-water densities were used for ice-margin habitat in both 
seasons. Harbor porpoise densities recorded during industry operations 
in the fall months of 2006-2008 were slightly lower than the summer 
months and ranged from 0.0002/km\2\ to 0.0010/km\2\ with a maximum 95 
percent CI of 0.0093/km\2\. The average of those three years (0.0001/
km\2\) was again used as the average density estimate and the high 
value 0.0011/km\2\ was used as the maximum estimate (Table 3).
    Other Cetaceans--The remaining five cetacean species that could be 
encountered in the Chukchi Sea during Statoil's planned activities 
include the humpback whale, killer whale, minke whale, fin whale, and 
narwhal. Although there is evidence of the occasional occurrence of 
these animals in the Chukchi Sea, it is unlikely that more than a few 
individuals will be encountered during the planned activities. George 
and Suydam (1998) reported killer whales, Brueggeman et al. (1990) and 
Haley et al. (2010) reported minke whale, and COMIDA (2009) and Haley 
et al. (2010) reported fin whales. Narwhal sightings in the Chukchi Sea 
have not been reported in recent literature, but subsistence hunters 
occasionally report observations near Barrow, and Reeves et al. (2002) 
indicated a small number of extralimital sightings in the Chukchi Sea.
(2) Pinnipeds
    Four species of pinnipeds may be encountered in the Chukchi Sea: 
Ringed seal, bearded seal, spotted seal, and ribbon seal. Each of these 
species, except the spotted seal, is associated with both the ice 
margin and the nearshore area. The ice margin is considered preferred 
habitat (as compared to the nearshore areas) during most seasons.
    Ringed and Bearded Seals--Ringed seal and bearded seal summer ice-
margin densities (Table 2) were taken from Bengtson et al. (2005) who 
conducted spring surveys in the offshore pack ice zone (zone 12P) of 
the northern Chukchi Sea. However, a correction for bearded seal 
availability bias, g(0), based on haulout and diving patterns was not 
available and used in the reported densities. Densities of ringed and 
bearded seals in open water are expected to be somewhat lower in the 
summer when preferred pack ice habitat may still be present in the 
Chukchi Sea. Average and maximum open-water densities have been 
estimated as \3/4\ of the ice margin densities during both seasons for 
both species. The fall density of ringed seals in the offshore Chukchi 
Sea has been estimated as \2/3\ the summer densities because ringed 
seals begin to reoccupy nearshore fast ice areas as it forms in the 
fall. Bearded seals may also begin to leave the Chukchi Sea in the 
fall, but less is known about their movement patterns so fall densities 
were left unchanged from summer densities. For comparison, the ringed 
seal density estimates calculated from data collected during summer 
2006-2008 industry operations ranged from 0.0158/km\2\ to 0.0687/km\2\ 
with a maximum 95 percent CI of 0.1514/km\2\ (Haley et al. 2010). These 
estimates are lower than those made by Bengtson et al. (2005) which is 
not surprising given the different survey methods and timing.
    Spotted Seal--Little information on spotted seal densities in 
offshore areas of the Chukchi Sea is available. Spotted seal densities 
in the summer were estimated by multiplying the ringed seal densities 
by 0.02. This was based on the ratio of the estimated Chukchi 
populations of the two species. Chukchi Sea spotted seal abundance was 
estimated by assuming that 8 percent of the Alaskan population of 
spotted seals is present in the Chukchi Sea during the summer and fall 
(Rugh et al. 1997), the Alaskan population of spotted seals is 59,214 
(Allen and Angliss 2010), and that the population of ringed seals in 
the Alaskan Chukchi Sea is ~208,000 animals (Bengtson et al. 2005). In 
the fall, spotted seals show increased use of coastal haulouts so 
densities in offshore areas were estimated to be \2/3\ of the summer 
densities.
    Ribbon Seal--Two ribbon seal sightings were reported during 
industry vessel operations in the Chukchi Sea in 2006-2008 (Haley et 
al. 2010). The resulting density estimate of 0.0005/km\2\ was used as 
the average density.

Potential Number of Takes by Harassment

    This subsection provides estimates of the number of individuals 
potentially exposed to sound levels >= 160 dBrms re 1 [mu]Pa 
by pulsed airgun sounds and to >= 120 dBrms re 1 [mu]Pa by 
non-impulse sounds during geotechnical soil investigations. The 
estimates are based on a consideration of the number of marine mammals 
that might be disturbed appreciably by operations in the Chukchi Sea 
and the anticipated area exposed to those sound levels.
    The number of individuals of each species potentially exposed to 
received levels of pulsed sounds >= 160 dBrms re 1 [mu]Pa or 
to >= 120 dBrms re 1 [mu]Pa by continuous sounds within each 
season and habitat zone was estimated by multiplying
     The anticipated area to be ensonified to the specified 
level in each season and habitat zone to which that density applies, by
     The expected species density.
    The numbers of individuals potentially exposed were then summed for 
each species across the two seasons and habitat zones. Some of the 
animals estimated to be exposed, particularly migrating bowhead whales, 
might show avoidance reactions before being exposed to pulsed airgun 
sounds >= 160 dBrms re 1 [micro]Pa. Thus, these calculations 
actually estimate the number of individuals potentially exposed to the 
specified sound levels that would occur if there were no avoidance of 
the area ensonified to that level.
    Site survey and geotechnical soil investigations are planned to 
occur primarily in August and September, with the potential to continue 
into mid-November, if necessary and weather permitting. For the 
purposes of assigning activities to the summer (August) and fall 
(September-October) periods for which densities have been estimated 
above, we have assumed that half of the operations will occur during 
the summer period and half will occur in the fall period. Additionally, 
the planned activities cannot be completed in or near significant 
amounts of sea ice, so 90% of the activity each season (and associated 
ensonified areas) has been multiplied by the open-water densities 
described above, while the remaining 10% of activity has been 
multiplied by the ice-margin densities.

[[Page 30125]]

    Species with an estimated average number of individuals exposed 
equal to zero are included below for completeness, but are not likely 
to be encountered.
(1) Shallow Hazards and Site Clearance Surveys
    The estimated numbers of marine mammals potentially exposed to 
airgun sounds with received levels >= 160 dBrms from site 
surveys on Statoil's leases are shown in Table 4. The average estimate 
of the number of individual bowhead whales exposed to received sound 
levels >= 160 dB is 11. The average estimate for gray whales is 
slightly greater at 18, while few belugas are expected to be exposed 
(Table 4). Few other cetaceans (such as narwhal, harbor porpoise, 
killer, humpback, fin, and minke whales) are likely to be exposed to 
airgun sounds >= 160 dB, but estimates have been included to account 
for chance encounters.
    Ringed seals are expected to be the most abundant animal in the 
Chukchi Sea during this period and the average estimate of the number 
exposed to >= 160 dB by site survey activities is 337 (Table 4). 
Estimated exposures of other seal species are substantially below those 
for ringed seals (Table 4).

Table 4--Summary of the Number of Marine Mammals in Areas Where Maximum Received Sound Levels in the Water Would
  Be >= 160 dB in Summer (Aug) and Fall (Sep-Oct) Periods During Statoil's Planned Site Surveys in the Chukchi
  Sea, Alaska. Not All Marine Mammals Are Expected To Change Their Behavior When Exposed to These Sound Levels
----------------------------------------------------------------------------------------------------------------
                                              Number of individuals exposed to sound levels >= 160 dB
                                 -------------------------------------------------------------------------------
             Species                          Summer                           Fall
                                 ----------------------------------------------------------------      Total
                                    Open water      Ice margin      Open water      Ice margin
----------------------------------------------------------------------------------------------------------------
Beluga whale....................               0               0               1               0               2
Narwhal.........................               0               0               0               0               2
Killer whale....................               0               0               0               0               2
Harbor porpoise.................               1               0               0               0               1
Bowhead whale...................               1               0              10               0              11
Gray whale......................              12               1               4               1              18
Humpback whale..................               0               0               0               0               2
Fin whale.......................               0               0               0               0               2
Minke whale.....................               0               0               0               0               2
Bearded seal....................               5               1               5               1              12
Ribbon seal.....................               0               0               0               0               1
Ringed seal.....................             171              25             115              25             337
Spotted seal....................               3               1               2               1               7
----------------------------------------------------------------------------------------------------------------

(2) Geotechnical Soil Investigations
    The estimated numbers of marine mammals potentially exposed to 
continuous sounds with received levels >= 120 dBrms from 
geotechnical soil investigations on Statoil's leases and jointly owned 
leases are shown in Table 5. The average estimate of the number of 
individual bowhead whales exposed to received sound levels >= 120 dB is 
15. The average estimate for gray whales is slightly larger at 26 
individuals (Table 5). Few other cetaceans (such as narwhal, harbor 
porpoise, killer, humpback, fin, and minke whales) are likely to be 
exposed to soil investigation sounds >= 120 dB, but estimates have been 
included to account for chance encounters.
    The average estimate of the number of ringed seals potentially 
exposed to >=120 dB by soil investigation activities is 467 (Table 5). 
Estimated exposures of other seal species are substantially below those 
for ringed seals (Table 5).

Table 5--Summary of the Number of Marine Mammals in Areas Where Maximum Received Sound Levels in the Water Would
       Be >= 120 dB in Summer (Aug) and Fall (Sep-Oct) Periods During Statoil's Planned Geotechnical Soil
  Investigations in the Chukchi Sea, Alaska. Not All Marine Mammals Are Expected To Change Their Behavior When
                                          Exposed to These Sound Levels
----------------------------------------------------------------------------------------------------------------
                                              Number of individuals exposed to sound levels >= 120 dB
                                 -------------------------------------------------------------------------------
             Species                          Summer                           Fall
                                 ----------------------------------------------------------------      Total
                                    Open water      Ice margin      Open water      Ice margin
----------------------------------------------------------------------------------------------------------------
Beluga whale....................               1               0               1               0               2
Narwhal.........................               0               0               0               0               3
Killer whale....................               0               0               0               0               3
Harbor porpoise.................               1               0               0               0               1
Bowhead whale...................               1               0              14               0              15
Gray whale......................              17               2               5               2              26
Humpback whale..................               0               0               0               0               3
Fin whale.......................               0               0               0               0               3
Minke whale.....................               0               0               0               0               3
Bearded seal....................               7               1               7               1              16
Ribbon seal.....................               0               0               0               0               1
Ringed seal.....................             238              35             159              35             467
Spotted seal....................               5               1               3               1              10
----------------------------------------------------------------------------------------------------------------


[[Page 30126]]

Estimated Take Conclusions

    Cetaceans--Effects on cetaceans are generally expected to be 
restricted to avoidance of an area around the seismic survey and short-
term changes in behavior, falling within the MMPA definition of ``Level 
B harassment''.
    Using the 160 dB criterion, the average estimates of the numbers of 
individual cetaceans exposed to sounds < 160 dBrms re 1 
[mu]Pa represent varying proportions of the populations of each species 
in the Beaufort Sea and adjacent waters. For species listed as 
``Endangered'' under the ESA, the estimates include approximately 26 
bowheads. This number is approximately 0.18% of the Bering-Chukchi-
Beaufort population of > 14,247 assuming 3.4% annual population growth 
from the 2001 estimate of > 10,545 animals (Zeh and Punt 2005). For 
other cetaceans that might occur in the vicinity of the shallow hazards 
survey in the Chukchi Sea, they also represent a very small proportion 
of their respective populations. The average estimates of the number of 
belugas, killer whales, harbor porpoises, gray whales, humpback whales, 
fin whales, and minke whales that might be exposed to <160 dB and 120 
dB re 1 [mu]Pa are 4, 5, 2, 44, 5, 5, and 5. These numbers represent 
0.11%, 1.59%, 0.004%, 0.25%, 0.53%, 0.09%, and 0.50% of these species 
of their respective populations in the proposed action area. No 
population estimates of narwhal are available in U.S. waters due to its 
extralimital distribution here. The world population of narwhal is 
estimated at 75,000 (Laidre et al. 2008), and most of them are 
concentrated in the fjords and inlets of Northern Canada and western 
Greenland. The estimated take of 5 narwhals represents approximately 
0.01% of its population.
    Seals--A few seal species are likely to be encountered in the study 
area, but ringed seal is by far the most abundant in this area. The 
average estimates of the numbers of individuals exposed to sounds at 
received levels <160 dBrms re 1 [mu]Pa during the proposed 
shallow hazards survey are as follows: ringed seals (803), bearded 
seals (28), spotted seals (17), and ribbon seals (2). These numbers 
represent 0.35%, 0.01%, 0.03%, and 0.002% of Alaska stocks of ringed, 
bearded, spotted, and ribbon seals, respectively.

Negligible Impact and Small Numbers Analysis and Preliminary 
Determination

    NMFS has defined ``negligible impact'' in 50 CFR 216.103 as ``* * * 
an impact resulting from the specified activity that cannot be 
reasonably expected to, and is not reasonably likely to, adversely 
affect the species or stock through effects on annual rates of 
recruitment or survival.'' In making a negligible impact determination, 
NMFS considers a variety of factors, including but not limited to: (1) 
The number of anticipated mortalities; (2) the number and nature of 
anticipated injuries; (3) the number, nature, intensity, and duration 
of Level B harassment; and (4) the context in which the takes occur.
    No injuries or mortalities are anticipated to occur as a result of 
Statoil's proposed 2011 open water marine shallow hazards surveys in 
the Chukchi Seas, and none are proposed to be authorized. In addition, 
these surveys would use a small 40 in\3\ airgun array and several mid- 
to high-frequency active acoustic sources. The acoustic power output is 
much lower than full scale airgun arrays used in a 2D or 3D seismic 
survey, and thus generates much lower source levels. The modeled 
isopleths at 160 dB is expected to be less than 2.25 km from the source 
(see discussion earlier). Additionally, animals in the area are not 
expected to incur hearing impairment (i.e., TTS or PTS) or non-auditory 
physiological effects. Takes will be limited to Level B behavioral 
harassment. Although it is possible that some individuals of marine 
mammals may be exposed to sounds from shallow hazards survey activities 
more than once, the expanse of these multi-exposures are expected to be 
less extensive since both the animals and the survey vessels will be 
moving constantly in and out of the survey areas.
    Most of the bowhead whales encountered during the summer will 
likely show overt disturbance (avoidance) only if they receive airgun 
sounds with levels >= 160 dB re 1 [mu]Pa. Odontocete reactions to 
seismic energy pulses are usually assumed to be limited to shorter 
distances from the airgun(s) than are those of mysticetes, probably in 
part because odontocete low-frequency hearing is assumed to be less 
sensitive than that of mysticetes. However, at least when in the 
Canadian Beaufort Sea in summer, belugas appear to be fairly responsive 
to seismic energy, with few being sighted within 6-12 mi (10-20 km) of 
seismic vessels during aerial surveys (Miller et al. 2005). Belugas 
will likely occur in small numbers in the Chukchi Sea during the survey 
period and few will likely be affected by the survey activity. In 
addition, due to the constant moving of the survey vessel, the duration 
of the noise exposure by cetaceans to seismic impulse would be brief. 
For the same reason, it is unlikely that any individual animal would be 
exposed to high received levels multiple times.
    For animals exposed to machinery noise from geotechnical oil 
investigations, NMFS considers that at received levels >= 120 dB re 1 
[mu]Pa, the animals could respond behaviorally in a manner that NMFS 
considers Level B harassment due to the non-pulse nature of the noise 
involved in this activity. During soil investigation operations, the 
most intensive noise source is from the dynamic positioning (DP) system 
that automatically controls and coordinates vessel movements using bow 
and/or stern thrusters. Measurements of a similar vessel in DP mode in 
the Chukchi Sea in 2010 provided an estimated source level at about 176 
dB re 1 [mu]Pa, which is below what NMFS uses to assess Level A 
harassment of received levels at 180 dB for cetaceans and 190 dB for 
pinnipeds. In addition, the duration of the entire geotechnical oil 
investigation is approximately 14 days, and DP will only be running 
sporadically when needed to position the vessel. In addition, the oil 
investigation operations are expected to be stationary, with limited 
area to be ensonified. Therefore, the impacts to marine mammals in the 
vicinity of the oil investigation operations are expected to be in 
short duration and localized.
    Taking into account the mitigation measures that are planned, 
effects on cetaceans are generally expected to be restricted to 
avoidance of a limited area around the survey operation and short-term 
changes in behavior, falling within the MMPA definition of ``Level B 
harassment''.
    Furthermore, the estimated numbers of animals potentially exposed 
to sound levels sufficient to cause appreciable disturbance are very 
low percentages of the population sizes in the Bering-Chukchi-Beaufort 
seas, as described above.
    The many reported cases of apparent tolerance by cetaceans of 
seismic exploration, vessel traffic, and some other human activities 
show that co-existence is possible. Mitigation measures such as 
controlled vessel speed, dedicated marine mammal observers, non-
pursuit, and shut downs or power downs when marine mammals are seen 
within defined ranges will further reduce short-term reactions and 
minimize any effects on hearing sensitivity. In all cases, the effects 
are expected to be short-term, with no lasting biological consequence.
    Some individual pinnipeds may be exposed to sound from the proposed 
marine surveys more than once during

[[Page 30127]]

the time frame of the project. However, as discussed previously, due to 
the constant moving of the survey vessel, the probability of an 
individual pinniped being exposed to sound multiple times is much lower 
than if the source is stationary. Therefore, NMFS has preliminarily 
determined that the exposure of pinnipeds to sounds produced by the 
proposed shallow hazards surveys and soil investigation in the Chukchi 
Sea is not expected to result in more than Level B harassment and is 
anticipated to have no more than a negligible impact on the animals.
    Of the thirteen marine mammal species likely to occur in the 
proposed marine survey area, only the bowhead, fin, and humpback whales 
are listed as endangered under the ESA. These species are also 
designated as ``depleted'' under the MMPA. Despite these designations, 
the Bering-Chukchi-Beaufort stock of bowheads has been increasing at a 
rate of 3.4 percent annually for nearly a decade (Allen and Angliss 
2010). Additionally, during the 2001 census, 121 calves were counted, 
which was the highest yet recorded. The calf count provides 
corroborating evidence for a healthy and increasing population (Allen 
and Angliss 2010). The occurrence of fin and humpback whales in the 
proposed marine survey areas is considered very rare. There is no 
critical habitat designated in the U.S. Arctic for the bowhead, fin, 
and humpback whale. The bearded and ringed seals are ``candidate 
species'' under the ESA, meaning they are currently being considered 
for listing but are not designated as depleted under the MMPA. None of 
the other species that may occur in the project area are listed as 
threatened or endangered under the ESA or designated as depleted under 
the MMPA.
    Potential impacts to marine mammal habitat were discussed 
previously in this document (see the ``Anticipated Effects on Habitat'' 
section). Although some disturbance is possible to food sources of 
marine mammals, the impacts are anticipated to be minor enough as to 
not affect rates of recruitment or survival of marine mammals in the 
area. Based on the vast size of the Arctic Ocean where feeding by 
marine mammals occurs versus the localized area of the marine survey 
activities, any missed feeding opportunities in the direct project area 
would be minor based on the fact that other feeding areas exist 
elsewhere.
    The estimated takes proposed to be authorized represent 0.11% of 
the Eastern Chukchi Sea population of approximately 3,710 beluga whales 
(Allen and Angliss 2010), 1.59% of Aleutian Island and Bering Sea stock 
of approximately 314 killer whales, 0.004% of Bering Sea stock of 
approximately 48,215 harbor porpoises, 0.25% of the Eastern North 
Pacific stock of approximately 17,752 gray whales, 0.18% of the Bering-
Chukchi-Beaufort population of 14,247 bowhead whales assuming 3.4 
percent annual population growth from the 2001 estimate of 10,545 
animals (Zeh and Punt, 2005), 0.53% of the Western North Pacific stock 
of approximately 938 humpback whales, 0.09% of the North Pacific stock 
of approximately 5,700 fin whales, and 0.50% of the Alaska stock of 
approximately 1,003 minke whales. The take estimates presented for 
bearded, ringed, spotted, and ribbon seals represent 0.01, 0.35, 0.03, 
and 0.002 percent of U.S. Arctic stocks of each species, respectively. 
These estimates represent the percentage of each species or stock that 
could be taken by Level B behavioral harassment if each animal is taken 
only once. In addition, the mitigation and monitoring measures 
(described previously in this document) proposed for inclusion in the 
IHA (if issued) are expected to reduce even further any potential 
disturbance to marine mammals.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the mitigation and monitoring 
measures, NMFS preliminarily finds that Statoil's proposed 2011 open 
water shallow hazards survey in the Chukchi Sea may result in the 
incidental take of small numbers of marine mammals, by Level B 
harassment only, and that the total taking from the marine surveys will 
have a negligible impact on the affected species or stocks. Impact on 
Availability of Affected Species or Stock for Taking for Subsistence 
Uses

Relevant Subsistence Uses

    The disturbance and potential displacement of marine mammals by 
sounds from the proposed marine surveys are the principal concerns 
related to subsistence use of the area. Subsistence remains the basis 
for Alaska Native culture and community. Subsistence hunting and 
fishing continue to be prominent in the household economies and social 
welfare of some Alaskan residents, particularly among those living in 
small, rural villages (Wolfe and Walker 1987). In rural Alaska, 
subsistence activities are often central to many aspects of human 
existence, including patterns of family life, artistic expression, and 
community religious and celebratory activities. Additionally, the 
animals taken for subsistence provide a significant portion of the food 
that will last the community throughout the year. The main species that 
are hunted include bowhead and beluga whales, ringed, spotted, and 
bearded seals, walruses, and polar bears. (Both the walrus and the 
polar bear are under the USFWS' jurisdiction.) The importance of each 
of these species varies among the communities and is largely based on 
availability.
    Marine mammals are legally hunted in Alaskan waters by coastal 
Alaska Natives; species hunted include bowhead and beluga whales; 
ringed, spotted, and bearded seals; walruses, and polar bears. The 
importance of each of the various species varies among the communities 
based largely on availability. Bowhead whales, belugas, and walruses 
are the marine mammal species primarily harvested during the time of 
the proposed shallow hazard survey. There is little or no bowhead 
hunting by the community of Point Lay, so beluga and walrus hunting are 
of more importance there. Members of the Wainwright community hunt 
bowhead whales in the spring, although bowhead whale hunting conditions 
there are often more difficult than elsewhere, and they do not hunt 
bowheads during seasons when Statoil's survey operation would occur. 
Depending on the level of success during the spring bowhead hunt, 
Wainwright residents may be very dependent on the presence of belugas 
in a nearby lagoon system during July and August. Barrow residents 
focus hunting efforts on bowhead whales during the spring and generally 
do not hunt beluga then. However, Barrow residents also hunt in the 
fall, when Statoil expects to be conducting shallow hazards surveys 
(though not near Barrow).
(1) Bowhead Whales
    Bowhead whale hunting is a key activity in the subsistence 
economies of northwest Arctic communities. The whale harvests have a 
great influence on social relations by strengthening the sense of 
Inupiat culture and heritage in addition to reinforcing family and 
community ties.
    An overall quota system for the hunting of bowhead whales was 
established by the International Whaling Commission (IWC) in 1977. The 
quota is now regulated through an agreement between NMFS and the Alaska 
Eskimo Whaling Commission (AEWC). The AEWC allots the number of bowhead 
whales that each whaling community may harvest annually (USDI/BLM 
2005). The annual take of bowhead whales has varied due to (a) changes 
in the allowable quota level and (b) year-to-

[[Page 30128]]

year variability in ice and weather conditions, which strongly 
influence the success of the hunt.
    Bowhead whales migrate around northern Alaska twice each year, 
during the spring and autumn, and are hunted in both seasons. Bowhead 
whales are hunted from Barrow during the spring and the fall migration 
and animals are not successfully harvested every year. The spring hunt 
along Chukchi villages and at Barrow occurs after leads open due to the 
deterioration of pack ice; the spring hunt typically occurs from early 
April until the first week of June. The fall migration of bowhead 
whales that summer in the eastern Beaufort Sea typically begins in late 
August or September. Fall migration into Alaskan waters is primarily 
during September and October.
    In the fall, subsistence hunters use aluminum or fiberglass boats 
with outboards. Hunters prefer to take bowheads close to shore to avoid 
a long tow during which the meat can spoil, but Braund and Moorehead 
(1995) report that crews may (rarely) pursue whales as far as 50 mi (80 
km). The autumn bowhead hunt usually begins in Barrow in mid-September, 
and mainly occurs in the waters east and northeast of Point Barrow.
    The scheduling of this shallow hazard survey has been discussed 
with representatives of those concerned with the subsistence bowhead 
hunt, most notably the AEWC, the Barrow Whaling Captains' Association, 
and the North Slope Borough (NSB) Department of Wildlife Management.
    The planned mobilization and start date for shallow hazards surveys 
in the Chukchi Sea (~25 July and ~1 August, respectively) is well after 
the end of the spring bowhead migration and hunt at Wainwright and 
Barrow. Shallow hazards survey and soil investigation operations will 
be conducted far offshore from Barrow and Wainwright are not expected 
to conflict with subsistence hunting activities. Specific concerns of 
the Barrow whaling captains are addressed as part of the Plan of 
Cooperation/Conflict Avoidance Agreement that is being negotiated with 
the AEWC (see below).
(2) Beluga Whales
    Beluga whales are available to subsistence hunters along the coast 
of Alaska in the spring when pack-ice conditions deteriorate and leads 
open up. Belugas may remain in coastal areas or lagoons through June 
and sometimes into July and August. The community of Point Lay is 
heavily dependent on the hunting of belugas in Kasegaluk Lagoon for 
subsistence meat. From 1983-1992 the average annual harvest was ~40 
whales (Fuller and George 1997). In Wainwright and Barrow, hunters 
usually wait until after the spring bowhead whale hunt is finished 
before turning their attention to hunting belugas. The average annual 
harvest of beluga whales taken by Barrow for 1962-1982 was five (MMS 
1996). The Alaska Beluga Whale Committee recorded that 23 beluga whales 
had been harvested by Barrow hunters from 1987 to 2002, ranging from 0 
in 1987, 1988 and 1995 to the high of 8 in 1997 (Fuller and George 
1997; Alaska Beluga Whale Committee 2002 in USDI/BLM 2005). The seismic 
survey activities take place well offshore, far away from areas that 
are used for beluga hunting by the Chukchi Sea communities.
(3) Ringed Seals
    Ringed seals are hunted mainly from October through June. Hunting 
for these smaller mammals is concentrated during winter because bowhead 
whales, bearded seals and caribou are available through other seasons. 
In winter, leads and cracks in the ice off points of land and along the 
barrier islands are used for hunting ringed seals. The average annual 
ringed seal harvest was 49 seals in Point Lay, 86 in Wainwright, and 
394 in Barrow (Braund et al. 1993; USDI/BLM 2003; 2005). Although 
ringed seals are available year-round, the planned activities will not 
occur during the primary period when these seals are typically 
harvested. Also, the activities will be largely in offshore waters 
where the activities will not influence ringed seals in the nearshore 
areas where they are hunted.
(4) Spotted Seals
    The spotted seal subsistence hunt peaks in July and August along 
the shore where the seals haul out, but usually involves relatively few 
animals. Spotted seals typically migrate south by October to overwinter 
in the Bering Sea. During the fall migration spotted seals are hunted 
by the Wainright and Point Lay communities as the seals move south 
along the coast (USDI/BLM 2003). Spotted seals are also occasionally 
hunted in the area off Point Barrow and along the barrier islands of 
Elson Lagoon to the east (USDI/BLM 2005). The planned activities will 
remain offshore of the coastal harvest area of these seals and should 
not conflict with harvest activities.
(5) Bearded Seals
    Bearded seals, although generally not favored for their meat, are 
important to subsistence activities in Barrow and Wainright, because of 
their skins. Six to nine bearded seal hides are used by whalers to 
cover each of the skin-covered boats traditionally used for spring 
whaling. Because of their valuable hides and large size, bearded seals 
are specifically sought. Bearded seals are harvested during the spring 
and summer months in the Chukchi Sea (USDI/BLM 2003; 2005). The animals 
inhabit the environment around the ice floes in the drifting nearshore 
ice pack, so hunting usually occurs from boats in the drift ice. Most 
bearded seals are harvested in coastal areas inshore of the proposed 
survey so no conflicts with the harvest of bearded seals are expected.
    In the event that both marine mammals and hunters are near the 
areas of planned operations, the proposed project potentially could 
impact the availability of marine mammals for harvest in a small area 
immediately around the vessel, in the case of pinnipeds, and possibly 
in a large area in the case of migrating bowheads. However, the 
majority of marine mammals are taken by hunters within ~21 mi (~33 km) 
from shore, and the survey activities will occur far offshore, well 
outside the hunting areas. Considering the timing and location of the 
proposed shallow hazards survey activities, as described earlier in the 
document, the proposed project is not expected to have any significant 
impacts to the availability of marine mammals for subsistence harvest. 
Specific concerns of the respective communities are addressed as part 
of the Plan of Cooperation between Statoil and the AEWC.

Potential Impacts to Subsistence Uses

    NMFS has defined ``unmitigable adverse impact'' in 50 CFR 216.103 
as:

* * * an impact resulting from the specified activity: (1) That is 
likely to reduce the availability of the species to a level 
insufficient for a harvest to meet subsistence needs by: (i) Causing 
the marine mammals to abandon or avoid hunting areas; (ii) Directly 
displacing subsistence users; or (iii) Placing physical barriers 
between the marine mammals and the subsistence hunters; and (2) That 
cannot be sufficiently mitigated by other measures to increase the 
availability of marine mammals to allow subsistence needs to be met.

    Noise and general activity during Statoil's proposed open water 
shallow hazards survey have the potential to impact marine mammals 
hunted by Native Alaskans. In the case of cetaceans, the most common 
reaction to anthropogenic sounds (as noted previously in this document) 
is avoidance of the ensonified area. In the case of bowhead whales, 
this often means that the animals divert from their

[[Page 30129]]

normal migratory path by several kilometers. Additionally, general 
vessel presence in the vicinity of traditional hunting areas could 
negatively impact a hunt.
    In the case of subsistence hunts for bowhead whales in the Chukchi 
Sea, there could be an adverse impact on the hunt if the whales were 
deflected seaward (further from shore) in traditional hunting areas. 
The impact would be that whaling crews would have to travel greater 
distances to intercept westward migrating whales, thereby creating a 
safety hazard for whaling crews and/or limiting chances of successfully 
striking and landing bowheads.
    In addition, Native knowledge indicates that bowhead whales become 
increasingly ``skittish'' in the presence of seismic noise. Whales are 
more wary around the hunters and tend to expose a much smaller portion 
of their back when surfacing (which makes harvesting more difficult). 
Additionally, natives report that bowheads exhibit angry behaviors in 
the presence of seismic, such as tail-slapping, which translate to 
danger for nearby subsistence harvesters.

Plan of Cooperation (POC or Plan)

    Regulations at 50 CFR 216.104(a)(12) require IHA applicants for 
activities that take place in Arctic waters to provide a POC or 
information that identifies what measures have been taken and/or will 
be taken to minimize adverse effects on the availability of marine 
mammals for subsistence purposes.
    Statoil states that it intends to maintain an open and transparent 
process with all stakeholders throughout the life-cycle of activities 
in the Chukchi Sea. Statoil began the stakeholder engagement process in 
2009 with meeting Chukchi Sea community leaders at the tribal, city, 
and corporate level. Statoil will continue to engage with leaders, 
community members, and subsistence groups, as well as local, state, and 
federal regulatory agencies throughout the exploration and development 
process.
    As part of stakeholder engagement, Statoil is developing a Plan of 
Cooperation (POC) for the proposed 2011 activities. The POC summarizes 
the actions Statoil will take to identify important subsistence 
activities, inform subsistence users of the proposed survey activities, 
and obtain feedback from subsistence users regarding how to promote 
cooperation between subsistence activities and the Statoil program.
    During the early phase of the POC process for the proposed project, 
Statoil met with the North Slope Borough Department of Wildlife 
Management (Dec 2010) and the AEWC (mini-convention in Barrow, Feb 
2011). Statoil also arranged to visit and hold public meetings in the 
affected Chukchi Sea villages, including Pt. Hope, Pt. Lay, Wainwright, 
and Barrow during the week of 21 March, 2011.
    Based upon these meetings, a draft POC document is being developed. 
Upon completion, the draft POC will be submitted to each of the 
community leaders Statoil visited during the March meetings as well as 
other interested community members. Statoil will also submit the draft 
POC to NMFS, USFWS, and BOEMRE.
    A final POC that documents all consultations with community 
leaders, subsistence user groups, individual subsistence users, and 
community members will be submitted to NMFS, USFWS, and BOEMRE upon 
completion of consultations.

Subsistence Mitigation Measures

    Statoil plans to introduce the following mitigation measures, plans 
and programs to potentially affected subsistence groups and 
communities. These measures, plans, and programs have been effective in 
past seasons of work in the Arctic and were developed in past 
consultations with these communities.
    Statoil will not be entering the Chukchi Sea until early August, so 
there will be no potential conflict with spring bowhead whale or beluga 
subsistence whaling in the polynya zone. Statoil's planned activities 
area is ~100 mi (~ 161 km) northwest of Wainwright which reduces the 
potential impact to subsistence hunting activities occurring along the 
Chukchi Sea coast.
    The communication center in Wainwright will be jointly funded by 
Statoil and other operators, and Statoil will routinely call the 
communication center according to the established protocol while in the 
Chukchi Sea. Depending on survey progress, Statoil may perform a crew 
change in the Nome area in Alaska. The crew change will not involve the 
use of helicopters. Statoil does have a contingency plan for a 
potential transfer of a small number of crew via ship-to-shore vessel 
at Wainwright. If this should become necessary, the Wainwright 
communications center will be contacted to determine the appropriate 
vessel route and timing to avoid potential conflict with subsistence 
users.
    Prior to survey activities, Statoil will identify transit routes 
and timing to avoid other subsistence use areas and communicate with 
coastal communities before operating in or passing through these areas.

Unmitigable Adverse Impact Analysis and Preliminary Determination

    NMFS has preliminarily determined that Statoil's proposed 2011 open 
water shallow hazards survey in the Chukchi Sea will not have an 
unmitigable adverse impact on the availability of species or stocks for 
taking for subsistence uses. This preliminary determination is 
supported by information contained in this document and Statoil's draft 
POC. Statoil has adopted a spatial and temporal strategy for its 
Chukchi Sea operations that should minimize impacts to subsistence 
hunters. Statoil will enter the Chukchi Sea far offshore, so as to not 
interfere with July hunts in the Chukchi Sea villages. After the close 
of the July beluga whale hunts in the Chukchi Sea villages, very little 
whaling occurs in Wainwright, Point Hope, and Point Lay. Although the 
fall bowhead whale hunt in Barrow will occur while Statoil is still 
operating (mid- to late September to October), Barrow is approximately 
150 mi (241 km) east of the eastern boundary of the proposed shallow 
hazards survey site. Based on these factors, Statoil's Chukchi Sea 
shallow hazards survey is not expected to interfere with the fall 
bowhead harvest in Barrow. In recent years, bowhead whales have 
occasionally been taken in the fall by coastal villages along the 
Chukchi coast, but the total number of these animals has been small.
    Adverse impacts are not anticipated on sealing activities since the 
majority of hunts for seals occur in the winter and spring, when 
Statoil will not be operating. Additionally, most sealing activities 
occur much closer to shore than Statoil's proposed shallow hazards 
survey area.
    Based on the measures described in Statoil's Draft POC, the 
proposed mitigation and monitoring measures (described earlier in this 
document), and the project design itself, NMFS has determined 
preliminarily that there will not be an unmitigable adverse impact on 
subsistence uses from Statoil's open water shallow hazards survey in 
the Chukchi Sea.

Endangered Species Act (ESA)

    There are three marine mammal species listed as endangered under 
the ESA with confirmed or possible occurrence in the proposed project 
area: The bowhead, humpback, and fin whales. NMFS' Permits, 
Conservation and Education Division has initiated consultation with 
NMFS' Protected

[[Page 30130]]

Resources Division under section 7 of the ESA on the issuance of an IHA 
to Statoil under section 101(a)(5)(D) of the MMPA for this activity. 
Consultation will be concluded prior to a determination on the issuance 
of an IHA.

National Environmental Policy Act (NEPA)

    In 2010, NMFS prepared an Environmental Assessment (EA) and issued 
findings of no significant impact (FONSIs) for open-water seismic and 
marine surveys in the Beaufort and Chukchi seas by Shell and Statoil. A 
review of Statoil's proposed 2011 open-water shallow hazards surveys 
indicates that the planned action is essentially the same as the marine 
survey conducted by Shell in 2010, but on a smaller scale. In addition, 
the review indicated that there is no significant change in the 
environmental baselines from what were analyzed in 2010. Therefore, 
NMFS is preparing a Supplemental EA which incorporates by reference the 
2010 EA and other related documents, and updates the activity to 
reflect the lower impacts compared to the previous season.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
authorize the take of marine mammals incidental to Statoil's 2011 open 
water shallow hazards survey in the Chukchi Sea, Alaska, provided the 
previously mentioned mitigation, monitoring, and reporting requirements 
are incorporated.

    Dated: May 17, 2011.
James H. Lecky,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2011-12666 Filed 5-23-11; 8:45 am]
BILLING CODE 3510-22-P