[Federal Register Volume 75, Number 109 (Tuesday, June 8, 2010)]
[Notices]
[Pages 32379-32398]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-13753]
[[Page 32379]]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XW13
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Open Water Marine Seismic 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
marine seismic survey in the Chukchi Sea, Alaska, between July through
November 2010. 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, twelve species of marine mammals
during the specified activity.
DATES: Comments and information must be received no later than July 8,
2010.
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
email 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 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 December 24, 2009, from Statoil for
the taking, by harassment, of marine mammals incidental to a 3D marine
seismic surveys in the Chukchi Sea, Alaska, during the 2010 open-water
season. After addressing comments from NMFS, Statoil modified its
application and submitted a revised application on April 12, 2010. The
April 12, 2010, application is the one available for public comment
(see ADDRESSES) and considered by NMFS for this proposed IHA.
This proposed marine seismic survey will use two towed airgun array
consisting of 26 active (10 spare) airguns with a maximum discharge
volume of 3,000 cubic inch (in\3\). The proposed 3D survey will take
place in a 915 mi\2\ (2,370 km\2\) survey area approximately 150 mi
(241 km) west of Barrow in water depth of approximately 100 to 165 ft
(30 to 50 m). The seismic survey is designed to collect 3D data of the
deep sub-surface in Statoil's Chukchi leases in support of future oil
and gas development within the area of coverage. The data will help
identify source rocks, migration pathways, and play types. In addition,
a 2D tie line survey has been designed as a second priority program to
acquire useful information in the region. The four stand alone 2D lines
(with a total length of approximately 420 mi or 675 km) are designed to
tie the details of the new high resolution 3D image to the surrounding
regional geology to facilitate interpretation of more regional trends.
The number of 2D km acquired will to some degree be dependent on the
2010 season's restrictive ice coverage and the 3D data acquisition
progress.
Statoil intends to conduct these marine surveys during the 2010
Arctic open-water season (July through November). Impacts to marine
mammals may occur from noise produced by airgun sources used in the
surveys.
Description of the Specified Activity
Statoil plans to conduct geophysical data acquisition activities in
the Chukchi Sea in the period July 15 through November 30, 2010. Data
acquisition is expected to take approximately 60 days (including
anticipated downtime), but the total period for this request is from
July 15 through November 30 to allow for unexpected downtime. The
project area
[[Page 32380]]
encompasses approximately 915 mi\2\ (2,370 km\2\) in Statoil lease
holdings in the Minerals Management Service (MMS) Outer Continental
Shelf (OCS) Lease Sale 193 area in the northern Chukchi Sea (Figure 1
of the Statoil IHA application). The activities consist of 3D seismic
data acquisition and a 2D tie line survey as a second priority program.
The entire 3D program, if it can be completed, will consist of
approximately 3,100 mi (4,990 km) of production line, not including
line turns. A total of four 2D well tie lines with a total length of
approximately 420 mi (675 km) are included in the survey plan as a
second priority program. The 3D seismic data acquisition will be
conducted from the M/V Geo Celtic. The M/V Geo Celtic will tow two
identical airgun arrays at approximately 20 ft (6 m) depth and at a
distance of about 902 ft (275 m) behind the vessel. Each array is
composed of three strings for a total of 26 active G-guns (4 60 in\3\,
8 70 in\3\, 6 100 in\3\, 4 150 in\3\, and 4 250 in\3\) with a total
discharge volume of 3000 in\3\. Each array also consists of 5 clusters
of 10 inactive airguns that will be used as spares. One of the smallest
guns in the array (60 in\3\) will be used as the mitigation gun. More
details of the airgun array and its components are described in
Appendix B of Statoil's IHA application. In addition to the airgun
array, pinger systems (DigiRANGE II, or similar systems) will be used
to position the streamer array relative to the vessel.
The estimated source level for the full 3000 in\3\ array is 245 dB
re 1 microPa (rms) at 1 m. The maximum distances to received levels of
190, 180 160, and 120 dB re 1 microPa (rms) from sound source
verification (SSV) measurements of the 3,147 in\3\ airgun array used in
the Chukchi Sea during 2006-2008 were used to model the received levels
at these distances, which show that the maximum distances are 700,
2,500, 13,000, and 120,000 m, respectively.
The estimated source level of this single 60 in\3\ airgun is 230 dB
re 1 microPa (rms) at 1 m, and the modeled distances to received levels
of 190, 180 160, and 120 dB re 1 microPa (rms) are 75, 220, 1,800, and
50,000 m, respectively.
The DigiRANGE II pinger system produces very short pulses,
occurring for 10 ms, with source level approximately 180 dB re 1
microPa (rms) at 1 m at 55 kHz, 188 dB re 1 microPa (rms) at 1 m at 75
kHz, and 184 dB re 1 microPa (rms) at 1 m at 95 kHz. One pulse is
emitted on command from the operator aboard the source vessel, which
under normal operating conditions is once every 10 s. Most of the
energy in the sound pulses emitted by this pinger is between 50 and 100
kHz. The signal is omnidirectional. Using simple spherical spreading
modeling for sound propagation, the calculated distances to received
levels of 180, 160, and 120 dB re 1 microPa (rms) are 2.5 m, 25 m, and
2,512 m, respectively. These distances are well within the radii for
airgun arrays and that of a single mitigation gun.
The vessel will travel along pre-determined lines at a speed of
about 4 - 5 knots while one of the airgun arrays discharges every 8 -
10 seconds (shot interval 61.52 ft [18.75 m]). The streamer hydrophone
array will consist of twelve streamers of up to approximately 2.2 mi (4
km) in length, with a total of 20,000 - 25,000 hydrophones at 6.6 ft (2
m) spacing. This large hydrophone streamer receiver array, designed to
maximize efficiency and minimize the number of source points, will
receive the reflected signals from the airgun array and transfer the
data to an on-board processing system.
A 2D tie line survey has been designed as a second priority program
to allow the vessel to acquire useful information in the region. The
four stand alone 2D lines have a total length of approximately 420 mi
(675 km) and are designed to tie the details of the new high resolution
3D image to known surrounding regional geology.
The approximate boundaries of the total surface area are between
71[deg] 30' N and 72[deg] 00' N and between 165[deg] W and 162[deg] 30'
W. The water depth in the survey area varies from 100 to 165 ft (30 to
50 m).
The vessels involved in the seismic survey activities will consist
of at least three vessels as listed below. Specifications of these
vessels (or equivalent vessels if availability changes) are provided in
Appendix A of Statoil's IHA application.
One (1) seismic source vessel, the M/V Geo Celtic or
similar equipped vessel, to tow the two 3,000 in\3\ airgun arrays and
hydrophone streamer for the 3D (and 2D) seismic data acquisition and to
serve as a platform for marine mammal monitoring;
One (1) chase/monitoring vessel, the M/V Gulf Provider or
similar equipped vessel, for marine mammal monitoring, crew transfer,
support and supply duties.
One (1) chase/monitoring vessel, the M/V Thor Alpha or
similar equipped vessel, for marine mammal monitoring, support and
supply duties.
The M/V Geo Celtic, or similar vessel, will arrive in Dutch Harbor
around mid July 2010. The vessels will be resupplied and the crew
changed at this port. Depending on ice conditions, all three vessels
will depart Dutch Harbor around mid/end July with an expected transit
time of approximately 5 days (weather depending). Directly upon arrival
in the 3D survey area, depending on ice conditions, the M/V Geo Celtic
will deploy the airgun array and start operating their guns for the
purpose of sound source verification measurements (see Statoil IHA
application for more details). The startup date of seismic data
acquisition is expected to be early/mid August but depends on local ice
conditions.
Upon completion of these measurements the seismic data acquisition
in the Chukchi Sea will start and, depending on the start date, is
expected to be completed in the first half of October. This is based on
an estimated duration of 60 days from first to last shot point
(including anticipated downtime). The data acquisition is a 24-hour
operation.
Description of Marine Mammals in the Area of the Specified Activity
Eight cetacean and four pinniped species under NMFS jurisdiction
could occur in the general area of Statoil's open water marine seismic
survey area in the Chukchi Sea. These species most likely to occur in
the general area project vicinity include two cetacean species: beluga
(Delphinapterus leucas) and bowhead whales (Balaena mysticetus), and
three seal species: ringed (Phoca hispida), spotted (P. largha), and
bearded seals (Erignathus barbatus). Most encounters are likely to
occur in nearshore shelf habitats or along the ice edge. The marine
mammal species that is likely to be encountered most widely (in space
and time) throughout the period of the open water seismic survey is the
ringed seal. Encounters with bowhead and beluga whales are expected to
be limited to particular regions and seasons, as discussed below.
Other marine mammal species that have been observed in the Chukchi
Sea but are less frequent or uncommon in the project area include
harbor porpoise (Phocoena phocoena), narwhal (Monodon monoceros),
killer whale (Orcinus orca), fin whale (Balaenoptera physalus), minke
whale (B. acutorostrata), humpback whale (Megaptera novaeangliae), gray
whale (Eschrichtius robustus), 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 marine seismic
survey. The narwhal occurs in Canadian waters
[[Page 32381]]
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). Point Barrow,
Alaska, is the approximate northeastern extent of the harbor porpoise's
regular range (Suydam and George 1992). Humpback, fin, and minke whales
have recently been sighted in the Chukchi Sea but very rarely in the
Beaufort Sea. Greene et al. (2007) reported and photographed a humpback
whale cow/calf pair east of Barrow near Smith Bay in 2007, which is the
first known occurrence of humpbacks in the Beaufort Sea. Savarese et
al. (2009) reported one minke whale sighting in the Beaufort Sea in
2007 and 2008. Ribbon seals do not normally occur in the Beaufort Sea;
however, two ribbon seal sightings were reported during vessel-based
activities near Prudhoe Bay in 2008 (Savarese et al. 2009).
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 2009 SAR is available at: http://www.nmfs.noaa.gov/pr/pdfs/sars/ak2009.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 shown that marine mammals at distances more than
a few kilometers from operating seismic vessels often show no apparent
response. That is often true even in cases when the pulsed sounds must
be readily audible to the animals based on measured received levels and
the hearing sensitivity of that mammal group. Although various baleen
whales, toothed whales, and (less frequently) pinnipeds have been shown
to react behaviorally to airgun pulses under some conditions, at other
times, mammals of all three types have shown no overt reactions. In
general, pinnipeds and small odontocetes seem to be more tolerant of
exposure to airgun pulses than baleen whales.
(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.
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 microPa 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 animal utilizes)
overlap at both spectral and temporal scales. For the airgun noise
generated from the proposed marine seismic survey, these are 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 sounds such as surf and prey noise. There is little
concern regarding masking due to the brief duration of these pulses and
relatively longer silence between airgun shots (9 - 12 seconds) near
the noise source, 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 microPa 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
[[Page 32382]]
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 microPa (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 microPa2-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 microPa rms. The established 180- and
190-dB re 1 microPa 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 to imply that TTS is unlikely to occur
unless bow-riding odontocetes are exposed to airgun pulses much
stronger than 180 dB re 1 microPa rms (Southall et al. 2007).
No cases of TTS are expected as a result of Statoil's proposed
seismic activity due to the fact that much higher received levels than
180- and 190-dB would be needed to induce TTS. In addition, 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 and monitoring measures prescribed (described below in the
document) will largely prevent marine mammals from being exposed to SPL
above 180 and 190 dB re 1 microPa (rms).
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 seismic survey 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 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.
(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
[[Page 32383]]
energetic and their peak amplitudes have slower rise times. Up-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 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 proposed seismic
survey.
Potential Effects from Pinger System on Marine Mammals
A pinger system (DigiRANGE II) will be used during seismic
operations to position the airgun array and hydrophone streamer
relative to the vessel. The specifications of the DigiRANGE II pinger
system (source levels and frequency ranges) are provided above. The
pinger produces sounds that are above the range of frequencies produced
or heard by mysticetes. However, the beluga whales and other
odontocetes have good hearing sensitivity across the pingers major
frequency range, which is at 50 - 100 kHz (Au et al. 1978; Johnson et
al. 1989). Some seals also can hear sounds at frequencies up to
somewhat above 55 kHz. In general, the potential effects of the pulse
pinger on marine mammals are similar to those from the airgun, but the
magnitude of the impacts is expected to be much less due to much lower
intensity and higher frequencies. Estimated source levels and zones of
influence from the pinger system are discussed above.
Vessel Sounds
In addition to the noise generated from seismic airguns, various
types of vessels will be used in the operations, including source
vessels and support vessels. 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). 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.
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. Icebreakers contribute greater sound
levels during ice-breaking activities than ships of similar size during
normal operation in open water (Richardson et al. 1995). This higher
sound production results from the greater amount of power and propeller
cavitation required when operating in thick ice. Source levels from
various vessels would be empirically measured before the start of
marine surveys.
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 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
[[Page 32384]]
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 marine seismic 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 marine seismic survey
activities.
As part of the application, Statoil submitted to NMFS a Marine
Mammal Monitoring and Mitigation Program (4MP) for its open water
seismic survey in the Chukchi Sea during the 2010 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 marine seismic 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 microPa
(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 2010 in the Chukchi Sea will be to measure the distances in
the broadside and endfire directions at which broadband received levels
reach 190, 180, 170, 160, and 120 dB re 1 microPa (rms) for the energy
source array combinations that may be used during the survey
activities. The configurations will include at least the full array and
the operation of a single mitigation source that will be used during
power downs. The measurements of energy source array sounds will be
made by an acoustics contractor at the beginning of the survey and 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 radii for zone of influence (ZOI). In
addition to reporting the radii of specific regulatory concern, nominal
distances to other sound isopleths down to 120 dB (rms) will be
reported in increments of 10 dB.
Data will be previewed in the field immediately after download from
the ocean bottom hydrophone (OBH) instruments. An initial sound source
analysis will be supplied to NMFS and the airgun operators within 120
hours of completion of the measurements, if possible. The report will
indicate the distances to sound levels between 190 dB re 1 microPa
(rms) and 120 dB re 1 microPa (rms) based on fits of empirical
transmission loss formulae to data in the endfire and broadside
directions. The 120-hour report findings will be based on analysis of
measurements from at least three of the OBH systems. A more detailed
report including analysis of data from all OBH systems 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 micro180 dB re 1 microPa (rms)
for cetaceans and micro190 dB re 1 microPa (rms) 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 survey activities have been estimated from measurements of
similar seismic arrays used in the Chukchi Sea in previous years. These
radii will be used for mitigation purposes until results of direct
measurements are available early during the exploration activities.
The basis for the estimation of distances to the four received
sound levels from the proposed 3000 in\3\ airgun array operating at a
depth of 20 ft (6 m) are the 2006, 2007 and 2008 sound source
verification (SSV) measurements in the Chukchi Sea of a similar array,
towed at a similar depth. The measured airgun array had a total
discharge volume of 3,147 in\3\ and was composed of three identically-
tuned Bolt airgun sub-arrays, totaling 24 airguns (6 clusters of 2
airguns and 12 single airguns). The proposed 3,000 in\3\ array is also
composed of three strings with a total of 26 active airguns in 13
clusters. The difference in discharge volume would lead to an expected
loss of less than 0.2 dB and is neglected in this assessment. The
estimated source level for the full 3,000 in\3\ array is 245 dB re 1
microPA (rms). Without measurement data for the specific site to be
surveyed, it is reasonable to adopt the maximum distances obtained from
a similar array during previous measurements in the Chukchi Sea. Table
1 summarizes the distances to received levels of 190, 180 160, and 120
dB re 1 microPa (rms) that are adopted for the analysis for the
proposed survey. Distances for received levels of 120 dB are highly
variable, in part because the bottom geoacoustic properties will have a
major effect on received levels at such distances.
[[Page 32385]]
To estimate the distances to various received levels from the 60
in\3\ mitigation gun the data from previous measurements of a 30 in\3\
gun were used. In general the pressure increase relative to a 30 in\3\
gun can be derived by calculating the square root of (60/30), which is
1.41. This means that the dB levels for the sound pressure levels of a
60 in\3\ will increase by approximately 3 dB (20Log[1.41]) compared to
the 30 in\3\ gun. The distances as summarized in Table 1 were derived
by adding 3 dB to the constant term of the equation RL = 226.6 -
21.2log(R) - 0.00022R. The estimated source level of this single 60
in\3\ airgun is 230 dB re 1 microPa (rms).
Table 1. Estimated distances to received sound levels micro190, 180, 170, 160, and 120 dB re 1 microPa (rms) from the 3,000 in\3\ airgun array and the
60 in\3\ mitigation gun of the proposed seismic survey. These distances are based on measurements in the Chukchi Sea from a similar airgun array.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Distance (m)
Received Levels (dB re 1 microPa rms) ------------------------------------------------------------------------------------------------------
3,000 in\3\ (full airgun array) 60 in\3\ (mitigation airgun)
--------------------------------------------------------------------------------------------------------------------------------------------------------
190 700 70
--------------------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------------------------------------------
An acoustics contractor will perform the direct measurements of the
received levels of underwater sound versus distance and direction from
the energy source arrays using calibrated hydrophones. The acoustic
data will be analyzed as quickly as reasonably practicable in the field
and used to verify (and if necessary adjust) the safety distances. The
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.
(3) Power Downs and Shut Downs
A power-down is the immediate reduction in the number of operating
energy sources from all firing to some smaller number. A shutdown is
the immediate cessation of firing of all energy sources. The arrays
will be immediately powered down whenever a marine mammal is sighted
approaching close to or within the applicable safety zone of the full
arrays but is outside or about to enter the applicable safety zone of
the single mitigation source. If a marine mammal is sighted within the
applicable safety zone of the single mitigation airgun, the entire
array will be shut down (i.e., no sources firing).
Following a power-down or shutdown, operation of the airgun array
will not resume until the marine mammal has cleared the applicable
safety zone. The animal will be considered to have cleared the safety
zone if it:
Is visually observed to have left the safety zone;
Has not been seen within the zone for 15 min in the case
of small odontocetes and pinnipeds; or
Has not been seen within the zone for 30 min in the case
of mysticetes.
(4) Ramp Ups
A ramp up of an airgun array provides a gradual increase in sound
levels, and involves a stepwise 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
time for them to leave the area and thus avoid any potential injury or
impairment of their hearing abilities.
During the proposed seismic survey, the seismic operator will ramp
up the airgun arrays 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. The actual time period
depends on ship speed and the size of the 180-dB safety radius. That
period is estimated to be about 15 - 20 minutes based on the modeling
results described above and a survey speed of 4 knots.
A full ramp up, after a shut down, will not begin until there has
been a minimum of 30 min 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 and transit between seismic transects, at least one
airgun will remain operational. The ramp-up procedure still will be
followed when increasing the source levels from one airgun to the full
arrays. 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, seismic operations can resume upon entry
to a new transect without a full ramp up and the associated 30-minute
lead-in observations. MMOs will be on duty whenever the airguns are
firing during daylight, and during the 30-min periods prior to ramp-ups
as well as during ramp-ups. Daylight will occur for 24 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 out at night to observe prior to and during any ramp up.
The seismic operator and MMOs will maintain records of the times when
ramp-ups start, and when the airgun arrays reach full power.
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
[[Page 32386]]
bowhead cow-calf pairs and aggregations of whales from seismic 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 seismic
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
nonmigratory, significant biological behavior (e.g., feeding,
socializing)) are observed during an aerial or vessel monitoring
program within the 160-dB safety zone around the seismic activity, the
seismic operation will not commence or will shut down, until two
consecutive surveys (aerial or vessel) indicate they are no longer
present within the 160-dB safety zone of seismic-surveying operations.
Survey information, especially information about bowhead
whale cow/calf pairs or feeding bowhead or gray whales, shall be
provided to NMFS as required in MMPA authorizations, and will form the
basis for NMFS determining whether additional mitigation measures, if
any, will be required over a given time period.
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 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 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 anticipates one crew change to occur approximately half-way
through the season. During crew rotations detailed hand-over notes will
be provided to the incoming crew leader by the outgoing leader. Other
communications such as email, fax, and/or phone communication between
the current and oncoming crew leaders during each rotation will also
occur when possible. In the event of an unexpected crew change Statoil
will facilitate such communications to insure monitoring consistency
among shifts.
Crew leaders and most other biologists serving as observers in 2010
will be individuals with experience as observers during one or more of
the 1996-2009 seismic or shallow hazards monitoring projects in Alaska,
the Canadian Beaufort, or other offshore areas in recent years.
Biologist-observers will have previous marine mammal observation
experience, and field crew leaders will be highly experienced with
previous vessel-based marine mammal monitoring and mitigation projects.
Resumes for those individuals will be provided to NMFS for review and
acceptance of their qualifications. Inupiat observers will be
experienced in the region, familiar with the marine mammals of the
area, and complete a NMFS approved observer training course designed to
familiarize individuals with monitoring and data collection procedures.
A marine mammal observers' handbook, adapted for the specifics of the
planned survey program, will be prepared and distributed beforehand to
all MMOs.
Most observers, including Inupiat observers, will also complete a
two or three-day training and refresher session on marine mammal
monitoring, to be conducted shortly before the anticipated start of the
2010 open-water season. Any exceptions will have or receive equivalent
experience or training. The training session(s) will be conducted by
qualified marine mammalogists with extensive crew-leader experience
during previous vessel-based seismic monitoring programs.
Primary objectives of the training include:
[[Page 32387]]
review of the marine mammal monitoring plan for this
project, including any amendments specified by NMFS in the IHA (if
issued), by USFWS and by MMS, 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 MMOs will watch for marine mammals from the best available
vantage point on the survey vessels, typically the bridge. The MMOs
will scan systematically with the unaided eye and 7 50 reticle
binoculars, supplemented during good visibility conditions with Fujinon
25x150 ``Big-eye'' binoculars mounted on a bride wing or flying bridge
(seismic vessel only), and night-vision equipment when needed (see
below). Personnel on the bridge will assist the marine mammal
observer(s) in watching for marine mammals. Data from the infrared
radar will be monitored in order to investigate if this could improve
the detection and record keeping of mammals, especially during periods
of low visibility.
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.
Distances to nearby marine mammals will be estimated with
binoculars (Fujinon 7 x 50 binoculars) containing a reticle to measure
the vertical angle of the line of sight to the animal relative to the
horizon. MMOs may use a laser rangefinder to test and improve their
abilities for visually estimating distances to objects in the water.
However, previous experience showed that a Class 1 eye-safe device was
not able to measure distances to seals more than about 230 ft (70 m)
away. The device was very useful in improving the distance estimation
abilities of the observers at distances up to about 1,968 ft (600 m)-
the maximum range at which the device could measure distances to highly
reflective objects such as other vessels. Humans observing objects of
more-or-less known size via a standard observation protocol, in this
case from a standard height above water, quickly become able to
estimate distances within about =20% when given immediate feedback
about actual distances during training.
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 Sea 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).
A prototype infrared radar will be mounted on the source vessel in
order to try to improve the visual observations during times of poor
visibility. The infrared radar detects thermal contrasts and its
ability to sense these differences is not dependent on daylight. It may
therefore improve the ability to detect marine mammals during
nighttime. The ability of the IR radar to detect marine mammals is not
yet proven and the intent is to collect data that can help determine if
it can be used as an effective monitoring tool in the future. However,
if during the course of testing, a reliable detection of a marine
mammal within a safety zone requiring a mitigation action is made using
the radar system, the necessary actions will be taken by the MMOs. That
is, even if the system is not entirely proven, reliable results made
during testing that may provide protection to marine mammals will not
be ignored.
(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 dB re 1 microPa (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. An acoustics contractor with experience in the Arctic
conducting similar measurements in recent years 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 2010 in the Chukchi Sea will be (1) to measure the
distances in the broadside and endfire directions at which broadband
received levels reach 190, 180, 170, 160, and 120 dB re 1 microPa (rms)
for the energy source array combinations that may be used during the
survey activities. The configurations will include at least the full
array and the operation of a single mitigation source that will be used
during power downs. The measurements of energy source array sounds will
be made by an acoustics contractor at the beginning of the survey and
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 dB re 1 microPa (rms) will be
reported in increments of 10 dB.
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 airgun operators 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.
[[Page 32388]]
2010 Shared Science Program
Statoil, Shell, and ConocoPhillips (CPAI) are jointly funding an
extensive science program in the Chukchi Sea. This program will be
carried out by Olgoonik-Fairweather LLC (OFJV) with the vessels
Norseman II and Westward Wind during the 2010 open water season. The
science program is not part of the Statoil seismic program, but worth
mentioning in this context due to the acoustic monitoring array
deployed within the seismic survey area as shown in Figures 1 and 2 of
Statoil's IHA application. The science program components include:
Acoustics Monitoring
Fisheries Ecology
Benthic Ecology
Plankton Ecology
Mammals
Seabirds
Physical Oceanography
The 2010 program continues the acoustic monitoring programs of
2006-2009 with a total of 44 acoustic recorders distributed both
broadly across the Chukchi lease area and nearshore environment and
intensively on the Statoil, Burger (Shell), and Klondike (CPAI) lease
holdings. The recorders will be deployed in late July or early August
and will be retrieved in early to mid-October, depending on ice
conditions. The recorders will be the Advanced Multi-Channel Acoustic
Recorder (AMAR) and the Autonomous Underwater Recorder for Acoustic
Listening (AURAL) model acoustic 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 - 2009. The broad area arrays
are designed to capture both general background soundscape data,
seismic survey sounds and marine mammal call data across the lease
area. From 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.
The site specific focused arrays are designed to also support
localization of marine mammal calls on and around the leaseholdings. In
the case of the Statoil prospect, where Statoil intends to conduct
seismic data acquisition in 2010, localized calls will enable
investigators to understand responses of marine mammals to survey
operations both in terms of distribution around the operation and
behavior (i.e. calling behavior). The site specific array will consist
of 7 AMAR recorders deployed in a hexagonal configuration as shown in
Figure 2 of Statoil's 4MP, with inter-recorder spacing of 8 km (12.9
mi). These recorders are the same types that were used successfully in
the 2009 site-specific acoustic monitoring program on Shell and CPAI
prospects. The recorded sample resolution is 24-bits and sample
frequency is 16 kHz, which is sufficient to capture part or all of the
sounds produced by the marine mammal species known to be present, with
the exception of harbor porpoise. The recorders will be synchronized to
support localization of calling bowhead whales. Other species' calls
are typically detected from distances less than the 8 km recorder
separation. Consequently the multi-sensor triangulation method, that is
used for bowheads calls, will not be used to determine calling
locations of other species; however, detection of other species' calls
indicates the animal position within a circular region of radius equal
to the maximum detection distances of a few kilometers.
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 marine seismic survey in the Chukchi
Sea, during 2010. The panel met and reviewed the plan in late March
2010, and provided comments to NMFS in late April 2010. NMFS 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-dB re 1 microPa (rms) 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 2010 open water marine survey monitoring
program (i.e., vessel-based, aerial, and acoustic), 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.
This information will be reported for both the vessel-based and
aerial monitoring.
(4) Comprehensive Report
Following the 2010 open-water season a comprehensive report
describing the
[[Page 32389]]
vessel-based, aerial, 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 2010. 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 seismic airgun(s) used in the seismic
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
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 dB re 1 microPa (rms) isopleth to
indicate the onset of Level B harassment. Statoil provided calculations
for the 160-dB isopleths produced by these active acoustic sources 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). However, NMFS consider that
narwhals are not likely to occur in the proposed survey area during the
time of the proposed marine seismic survey. Therefore, NMFS considers
that only the other 12 marine mammal species could be affected by Level
B behavioral harassment as a result of the proposed marine surveys.
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 dB re
1microPa (rms). 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
the more severe reactions did not occur until sounds were much higher
than 160 dB re 1microPa (rms).
As described earlier in the document, the proposed open water
marine seismic survey would use two airgun arrays with a total
discharge volume of 3,000 in\3\. The modeled 160 dB zone of influence
reaches to 13 km from the airgun source. The estimated number of
animals potentially harassed was calculated by multiplying the expected
densities (in number/km\2\) by the anticipated area ensonified by
levels of micro160 dB re 1microPa. Estimates of the number of animals
potentially impacted were conducted separately for the 3D survey area
and the 2D survey lines. For the 3D survey area, the anticipated area
ensonified by sound levels of micro160 dB was calculated as an area
encompassing a 8.1 mi (13 km) radius extending from each point of the
survey area perimeter (hereafter called the 160 dB exposed survey
area). This approach was taken because closely spaced survey lines and
large cross-track distances of the micro160 dB radii result in repeated
exposure of the same area of water. Excessive amounts of repeated
exposure leads to an overestimation of the number of animals
potentially exposed. For the 2D survey lines the area ensonified by
sound levels of micro160 dB was calculated as the total line kilometers
multiplied by 2 times the 8.1 mi (13 km) micro160 dB safety radius. The
following subsections describe in more detail the data and methods used
in deriving the estimated number of animals potentially ``taken by
harassment'' during the proposed survey. It provides information on the
[[Page 32390]]
expected marine mammal densities, estimated distances to received
levels of 190, 180, 160, and 120 dB re 1microPa and the calculation of
anticipated areas ensonified by levels of micro160 dB.
It is important to understand that not all published results from
visual observations have applied correction factors that account for
detectability and availability bias. Detectability bias, quantified in
part by f(0), is associated with diminishing sightability with
increasing lateral distance from the survey trackline. Availability
bias [g(0)] refers to the fact that not all animals are at the surface
and that there is therefore <100% probability of sighting an animal
that is present along the survey trackline. Some sources below included
correction factors in the reported densities (e.g., ringed seals in
Bengtson et al. 2005) and the best available correction factors were
applied to reported results when they had not already been included
(e.g., Moore et al. 2000b).
(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 beluga in offshore waters are
expected to be low. Aerial surveys have recorded few belugas in the
offshore Chukchi Sea during the summer months (Moore et al. 2000b).
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 sightings during >8,700 mi
(>14,000 km) of on-transect effort, only 2 of which were offshore
(COMIDA 2009). Additionally, only one beluga sighting was recorded
during >37,904 mi (>61,000 km) of visual effort during good visibility
conditions from industry vessels operating in the Chukchi Sea in
JulymicroAugust of 2006micro2008 (Haley et al. 2009b). 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 were calculated from data in Moore et al. (2000b). Data from
Moore et al. (2000b: Figure 6 and Table 6) used as the average open-
water density estimate included two on-transect beluga sightings during
6,639 mi (10,684 km) of on-transect effort in the Chukchi Sea during
summer. A mean group size of 7.1 (CV=1.7) was calculated from 10
Chukchi Sea summer sightings present in the BWASP database. A f(0)
value of 2.841 and g(0) value of 0.58 from Harwood et al. (1996) were
also used in the calculation. The CV associated with group size was
used to select an inflation factor of 2 to estimate the maximum density
that may occur in both open-water and ice-margin habitats. Specific
data on the relative abundance of beluga in open-water versus ice-
margin habitat during the summer in the Chukchi Sea is not available.
However, Moore et al. (2000b) reported higher than expected beluga
sighting rates in open-water during fall surveys in the Beaufort and
Chukchi Seas. This would suggest that densities near ice may actually
be lower than open water, but belugas are commonly associated with ice,
so an inflation factor of only 2 (instead of 4) was used to estimate
the average ice-margin density from the open-water density. Based on
the very low densities observed from vessels operating in the Chukchi
Sea during non-seismic periods and locations in JulymicroAugust of
2006-2008 (0.0001/km\2\; Haley et al. 2009b), the densities shown in
Table 1 are likely biased high.
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 (Angliss and Allen
2009). Consistent with this, the number of on-effort beluga sightings
reported during COMIDA flights in September-October of 2008-2009 was
over 3 times more than during July-August with a very similar amount of
on-transect effort (COMIDA 2009). However, there were no beluga
sightings reported during >11,185 mi (>18,000 km) of vessel based
effort in good visibility conditions during 2006-2008 industry
operations in the Chukchi Sea. Densities derived from survey results in
the northern Chukchi Sea in Moore et al. (2000b) were used as the
average density for open-water and ice-margin fall season estimates
(see Table 2). Data from Moore et al. (2000b: Table 8) used in the
average open-water density estimate included 123 beluga sightings and
27,559 mi (44,352 km) of on-transect effort in water depths 118-164 ft
(36-50 m). A mean group size of 2.39 (CV=0.92) came from the average
group size of 82 Chukchi Sea fall sightings in waters 115-164 ft (35-50
m) deep present in the BWASP database. A f(0) value of 2.841 and g(0)
value of 0.58 from Harwood et al. (1996) were used in the calculation.
The CV associated with group size was used to select an inflation
factor of 2 to estimate the maximum density that may occur in both
open-water and ice-margin habitats. Moore et al. (2000b) reported
higher than expected beluga sighting rates in open-water during fall
surveys in the Beaufort and Chukchi seas, so an inflation value of only
2 was used to estimate the average ice-margin density from the open-
water density. There were no beluga sightings from vessels operating in
the Chukchi Sea during non-seismic periods in September-October of
2006-2008 (Haley et al. 2009b).
Table 1. Expected densities of cetaceans and seals in areas of the Chukchi Sea, Alaska, during the planned
summer (July - August) period of the seismic survey program.
----------------------------------------------------------------------------------------------------------------
Nearshore Average Density Ice Margin Average Density
Species (/km\2\) (/ km\2\)
----------------------------------------------------------------------------------------------------------------
Beluga whale 0.0033 0.0162
----------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------------
[[Page 32391]]
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Table 2. Expected densities of cetaceans and seals in areas of the Chukchi Sea, Alaska, during the planned fall
(September - October) period of the seismic survey program.
----------------------------------------------------------------------------------------------------------------
Nearshore Average Density Ice Margin Average Density
Species (/km\2\) (/ km\2\)
----------------------------------------------------------------------------------------------------------------
Beluga whale 0.0162 0.0324
----------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------
-----------------------------------------------------------------------------------=============================
----------------------------------------------------------------------------------------------------------------
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 6,639 mi
(10,684 km) of on-transect effort in the Chukchi Sea by Moore et al.
(2000b). Aerial surveys in 2008-2009 by the NMML as part of the COMIDA
project reported four sightings during >8,699 mi (>14,000 km) of on-
transect effort. Two of the four sightings were offshore, both of which
occurred near the end of August. Bowhead whales were also rarely
reported in July-August of 2006-2008 during aerial surveys of the
Chukchi Sea coast (Thomas et al. 2009). This is consistent with
movements of tagged whales (see ADFG 2009; Quakenbush 2009), 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 bowhead whale density in the Chukchi Sea was
calculated by assuming that there was one bowhead sighting during the
6,639 mi (10,684 km) survey effort in the Chukchi Sea during the
summer, although no bowheads were actually observed (Moore et al.
2000b). The more recent COMIDA data were not used because the NMML has
not released a final report summarizing the data. Only two sightings
are present in the BWASP database during July and August in the Chukchi
Sea, both of which were of individual whales. The mean group size from
combined July-August sightings in the BWASP, COMIDA, and 2006-2008
industry database is 1.33 (CV=0.58). This 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. The CV of
group size and standard errors reported in Thomas et al. (2002) for
f(0) and g(0) correction factors suggest that an inflation factor of 2
is appropriate for deriving a maximum density from the average density.
Bowheads are not expected to be encountered in higher densities near
ice in the summer (Moore et al. 2000b), 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. 2009b) ranged from
0.0001/km\2\ to 0.0005/km\2\ with a
[[Page 32392]]
maximum 95 percent confidence interval (CI) of 0.0019 km\2\. This
suggests that the densities used in the calculations and shown in Table
1 might be somewhat higher than expected to be observed from vessels
near the area of planned operations.
During the fall, bowhead whales migrate west and south from their
summer feeding grounds in the Beaufort Sea and Amundsen Gulf to their
wintering grounds in the Bering Sea. During this fall migration
bowheads are more likely to be encountered in the Chukchi Sea. Moore et
al. (2000b: Table 8) reported 34 bowhead sightings during 27,560 mi
(44,354 km) of on-transect survey effort in the Chukchi Sea during
September-October. Thomas et al. (2009) also reported increased
sightings on coastal surveys of the Chukchi Sea during September and
October of 2006-2008. Aerial surveys in 2008-2009 (COMIDA 2009)
reported 20 bowhead sightings during 8,803 mi (14,167 km) of on-
transect effort, eight of which were offshore. GPS tagging of bowheads
show that migration routes through the Chukchi Sea are more variable
than through the Beaufort Sea (ADFG 2009; Quakenbush 2009). Some of the
routes taken by bowheads remain well north or south of the planned
survey 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 (ADFG
2009). The mean group size from September-October Chukchi Sea bowhead
sightings in the BWASP database is 1.59 (CV=1.08). This is slightly
below the mean group size of 1.85 from all the preliminary COMIDA
sightings during the same months, but above the value of 1.13 from only
on-effort COMIDA sightings (COMIDA 2009). The same f(0) and g(0) values
that were used for the summer estimates above were used for the fall
estimates. As with the summer estimates, an inflation factor of 2 was
used to estimate the maximum density from the average density in both
habitat types. Moore et al. (2000b) 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. Densities from vessel based
surveys in the Chukchi Sea during non-seismic periods and locations in
SeptembermicroOctober of 2006-2008 (Haley et al. 2009b) ranged from
0.0001/km\2\ to 0.0050/km\2\ with a maximum 95 percent CI of 0.0480
km\2\. This suggests the densities used in the calculations and shown
in Table 2 are somewhat higher than are likely to be observed from
vessels near the area of planned operations.
Gray Whales - The average open-water summer density was calculated
from effort and sightings in Moore et al. (2000b: Table 6) for water
depths 118-164 ft (36-50 m) including 4 sightings during 3,901 mi
(6,278 km) of on-transect effort. An average group size of 3.11
(CV=0.97) was calculated from all July-August Chukchi Sea gray whale
sightings in the BWASP database and used in the summer density
estimate. This value was higher than the average group size in the
preliminary COMIDA data (1.71; COMIDA 2009) and from coastal aerial
surveys in 2006-2008 (1.27; Thomas et al. 2009). 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. Since
the group size used in the average density estimate was relatively high
compared to other data sources and the CV was near to one, an inflation
factor of 2 was used to estimate the maximum densities from average
densities in both habitat types. Gray whales are not commonly
associated with sea ice, but may occur close to sea ice, so the
densities for open-water habitat were also used for ice-margin habitat.
Densities from vessel based surveys in the Chukchi Sea during non-
seismic periods and locations in July-August of 2006-2008 (Haley et al.
2009b) ranged from 0.0009/km\2\ to 0.0034/km\2\ with a maximum 95
percent CI of 0.0146 km\2\. This suggests that the densities used in
the calculations and shown in Table 1 are somewhat higher than are
expected to be observed from vessels near the area of planned
operations.
Gray whale densities are expected to be much higher in the summer
months than during the fall when most whales start their southbound
migration. Moore et al. (2000b) found that the distribution of gray
whales was more widely dispersed through the northern Chukchi Sea and
limited to nearshore areas where most whales were observed in water
less than 115 ft (35 m) deep. With similar amounts of on-transect
effort between summer and fall aerial surveys in 2008-2009, gray whale
sightings were three times higher in July-August than in September-
October, and five times higher taking into account all effort and
sightings (COMIDA 2009). Thomas et al. (2009) also reported decreased
sighting rates of gray whales in the fall.
The on-transect effort and associated gray whale sightings (27
sightings during 44,352 km of on-transect effort) in water depth of
118-164 ft (36-50 m) during autumn (Moore et al. 2000b; 12) was used as
the average density estimate for the Chukchi Sea during the fall
period. A group size value of 2.49 (CV=1.37) calculated from the BWASP
database was used in the density calculation, along with the same f(0)
and g(0) values described above. The group size value of 2.49 was again
higher than the average group size calculated from preliminary COMIDA
data (1.24; COMIDA 2009) and as reported from coastal aerial surveys in
2006-2008 (1.12; Thomas et al. 2009). Densities from vessel based
surveys in the Chukchi Sea during non-seismic periods and locations in
September-October of 2006-2008 (Haley et al. 2009b) ranged from 0.0011/
km\2\ to 0.0024/km\2\ with a maximum 95 percent CI of 0.0183 km\2\.
This suggests the densities used in the calculations and shown in Table
2 are somewhat higher than are likely to be observed from vessels near
the area of planned operations.
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. For this reason, the data collected from industry
vessels was considered to be the best available data. 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 0.0009/km\2\ to 0.0016/km\2\ with
a maximum 95 percent CI of 0.0016/km\2\ (Haley et al. 2009b). The
median value from the summer season of those three years (0.0011/km\2\)
was used as the average open-water density estimate while the high
value (0.0016/km\2\) was used as the maximum estimate (Table 1). 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 and ranged from
0.0002/km\2\ to 0.0013/km\2\ with a maximum 95 percent CI of 0.0044/
km\2\. The median value (0.0010/km\2\) was again used as the average
density estimate and the high value (0.0013/km\2\) was used as the
maximum estimate (Table 2).
Other Cetaceans - The remaining four cetacean species that could be
[[Page 32393]]
encountered in the Chukchi Sea during Statoil's planned seismic survey
include the humpback whale, killer whale, minke whale, and fin whale.
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 proposed activities. George
and Suydam (1998) reported killer whales, Brueggeman et al. (1990) and
Haley et al. (2009b) reported minke whale, and COMIDA (2009) and Haley
et al. (2009b) reported fin whales off of Ledyard Bay 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 average
summer ice-margin densities (Table 1) were available in Bengtson et al.
(2005) from spring surveys in the offshore pack ice zone (zone 12P) of
the northern Chukchi Sea. However, corrections for bearded seal
availability, g(0), based on haulout and diving patterns were not
available. 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 the summer 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 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 2006micro2008 industry operations ranged from
0.0082/km\2\ to 0.0221/km\2\ with a maximum 95 percent CI of 0.0577/
km\2\ (Haley et al. 2009b). 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 seals are often
considered to be predominantly a coastal species except in the spring
when they may be found in the southern margin of the retreating sea
ice, before they move to shore. However, satellite tagging has shown
that they sometimes undertake long excursions into offshore waters
during summer (Lowry et al. 1994, 1998). 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% 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 (Angliss and Allen 2009),
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 were estimated to
be 2/3 of the summer densities.
Ribbon Seal - Ribbon seals have been reported in very small numbers
within the Chukchi Sea by observers on industry vessels (two sightings;
Haley et al. 2009b). The resulting density estimate of 0.0003/km\2\ was
used as the average density and a multiplier of 4 was used as the
estimated maximum density for both seasons and habitat zones.
Potential Number of Takes by Harassment
This subsection provides estimates of the number of individuals
potentially exposed to sound levels micro160 dB re 1 microPa (rms). 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 rms sound levels of 160 dB.
As described above, marine mammal density estimates for the Chukchi
Sea have been derived for two time periods, the summer period (July-
August), and the fall period (September-October). Animal densities
encountered in the Chukchi Sea during both of these time periods will
further depend on the habitat zone within which the source vessel is
operating, i.e., open water or ice margin. The seismic source vessel is
not an icebreaker and cannot tow survey equipment through pack ice.
Under this assumption, densities of marine mammals expected to be
observed near ice margin areas have been applied to 10% of the proposed
3D survey area and 2D tracklines in both seasons. Densities of marine
mammals expected to occur in open water areas have been applied to the
remaining 90% of the 3D survey and 2D tracklines area in both seasons.
The number of individuals of each species potentially exposed to
received levels micro160 dB re 1 microPa (rms) 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 [gteqt]160 dB re
1 microPa (rms). Thus, these calculations actually estimate the number
of individuals potentially exposed to micro160 dB that would occur if
there were no avoidance of the area ensonified to that level.
(1) 3D Seismic Survey Area
The size of the proposed 3D seismic survey area is 915 mi\2\ (2,370
km\2\) and located >100 mi (160 km) offshore. Approximately 1/4 of the
area (~234 mi\2\, or ~606 km\2\) is expected to be surveyed in August
(weather depending). This area, with a 160 dB radius of 8 mi (13 km)
along each point of its perimeter equals a total area of ~1,081 mi\2\
(~2,799 km\2\). Summer marine mammal densities from Table 1 have been
applied to this area. The other 3/4 of the survey area (~687 mi\2\, or
~1,779 km\2\) is expected to be covered in September-October. This
area, also with a 160 dB radius of 8 mi (13 km) along each point of its
perimeter results in a total area of ~1,813 mi\2\ (~4,695 km\2\). Fall
marine mammal densities from Table 2 have been applied to this area.
Based on these assumptions and those described above, the estimates of
marine mammals potentially exposed to sounds micro160 dB in the Chukchi
Sea from seismic data acquisition in the 3D survey area were calculated
in Table 3.
For the common species, the requested numbers were calculated as
described above and based on the average and maximum densities
reported. For less common species, for which minimum density estimates
were assumed, the numbers were set to a minimum to allow for chance
encounters. The mitigation gun (60 in\3\) will be active during turns
extending about 1.6 mi (2.5 km) outside the 3D survey area. The
estimated 160 dB radius for the 60 in\3\ mitigation gun is 5,906 ft
(1,800 m) and therefore falls well within the area expected to be
[[Page 32394]]
exposed to received sound levels of [gteqt]160 dB of the 3D survey
area.
Table 3. Summary of the Number of Potential Exposures of Marine Mammals to Received Sound Levels in the Water of >160 dB During Statoil's Planned Marine
Seismic Survey in the Chukchi Sea, Alaska, 2010.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Number of Exposure to Sound Number of Exposure to Sound Total Number of Exposure to
Species Levels >160 dB re 1 microPa Levels >160 dB re 1 microPa Sound Levels >160 dB re 1
(rms) by 3D Seismic Survey (rms) by 2D Seismic Survey microPa (rms)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Beluga whale 97 87 184
---------------------------------------------------------
Killer whale 1 1 2
---------------------------------------------------------
Harbor porpoise 8 13 21
---------------------------------------------------------
Bowhead whale 95 63 158
---------------------------------------------------------
Gray whale 52 92 144
---------------------------------------------------------
Humpback whale 1 1 2
---------------------------------------------------------
Fin whale 1 1 2
---------------------------------------------------------
Minke whale 1 1 2
---------------------------------------------------------
Bearded seal 82 132 214
---------------------------------------------------------
Ribbon seal 2 4 6
---------------------------------------------------------
Ringed seal 2,253 4,234 6,487
---------------------------------------------------------
Spotted seal 45 85 130
--------------------------------------------------------------------------------------------------------------------------------------------------------
(2) 2D Seismic Survey Lines
Seismic data along the ~420 mi (675 km) of four 2D survey
tracklines might be acquired with the full airgun array if access to
the 3D survey area is restricted (e.g., ice conditions), or 3D
acquisition progress is better than anticipated. Under the assumption
that these restrictive weather conditions will mainly be an issue in
the early summer season, 80 % of the 2D tracklines are assumed to be
acquired during August and 20% during the fall. The total area
potentially exposed to micro160 dB from these tracklines was calculated
with the trackline sections outside the 3D survey area. Excluding these
sections results in a total trackline length of ~285 mi (460 km). With
a 160 dB radius of ~8 mi (13 km) this results in a total exposed area
of ~7,432 mi\2\ (11,960 km\2\). Such summer densities were used for 80%
of the total area (5,945 mi\2\, or 9,568 km\2\) and fall densities for
the remaining 20% (1,486 mi\2\, or 2,392 km\2\). Following a similar
approach as for the 3D survey area, numbers of more common marine
mammal species were calculated based on the average and maximum
densities and for less common species the numbers were set to a minimum
to allow for chance encounters. The results of estimates of marine
mammals potentially exposed to sounds micro160 dB in the Chukchi Sea
from seismic data acquisition along the 2D tracklines are presented in
Table 3.
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 [gteqt]160 dB re 1 microPa (rms)
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 158 bowheads. This
number is approximately 1.11% 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 marine seismic 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, fin whales, humpback
whales, and minke whales that might be exposed to [gteqt]160 dB re 1
microPa (rms) are 183, 2, 21, 144, 2, 2, and 2. These numbers represent
4.95%, 0.62%, 0.04%, 0.81%, 0.03%, 0.21%, and 0.19% of these species of
their respective populations in the proposed action area.
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 [gteqt]160 dB re 1 microPa (rms) during the proposed
seismic survey are as follows: ringed seals (6,487), bearded seals
(215), spotted seals (129), and ribbon seals (6). These numbers
represent 2.81%, 0.09%, 0.22%, and 0.01% of Alaska stocks of ringed,
bearded, spotted, and ribbon seals.
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
[[Page 32395]]
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 2010 open water marine seismic surveys in the
Chukchi Seas, and none are proposed to be authorized. 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 marine
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 [gteqt]160 dB re 1 microPa (rms). 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 seismic 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.
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 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 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 marine seismic survey 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 twelve 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 three 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 4.95% of
the Eastern Chukchi Sea population of approximately 3,700 beluga whales
(Angliss and Allen 2009), 0.62% of Aleutian Island and Bering Sea stock
of approximately 340 killer whales, 0.04% of Bering Sea stock of
approximately 48,215 harbor porpoises, 0.81% of the Eastern North
Pacific stock of approximately 17,752 gray whales, 1.11% of the Bering-
Chukchi-Beaufort population of 14,247 individuals assuming 3.4 percent
annual population growth from the 2001 estimate of 10,545 animals (Zeh
and Punt, 2005), 0.21% of the Western North Pacific stock of
approximately 938 humpback whales, 0.03% of the North Pacific stock of
approximately 5,700 fin whales, and 0.19% of the Alaska stock of
approximately 1,003 minke whales. The take estimates presented for
bearded, ringed, spotted, and ribbon seals represent 0.09, 2.81, 0.22,
and 0.01 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 2010 open
water marine seismic 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.
[[Page 32396]]
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. Marine mammals are legally
hunted in Alaskan waters by coastal Alaska Natives. 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.
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). Subsistence remains the basis for Alaska Native culture
and community. 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.
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 seismic 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 seismic 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 seismic 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-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 seismic 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 seismic surveys in the
Chukchi Sea (~20 July and ~1 August) is well after the end of the
spring bowhead migration and hunt at Wainwright and Barrow. Seismic
operations will be conducted far offshore from Barrow and 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 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. It is
possible, but unlikely, that accessibility to belugas during the
subsistence hunt could be impaired during the survey.
(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 seismic
[[Page 32397]]
survey will not occur during the primary period when these seals are
typically harvested. Also, the seismic survey 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 seismic survey 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 3D
survey area when seismic surveys are in progress, 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 (Figure 2 in Statoil's IHA
application), and the seismic source vessel M/V Geo Celtic will remain
far offshore, well outside the hunting areas. Considering the timing
and location of the proposed seismic 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
marine seismic 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 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.
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 2010 seismic acquisition. 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.
Statoil has had the opportunity to engage with North Slope
subsistence communities on several occasions:
October 27, 2009, presentation to the NSB Planning
Commission in Barrow;
October 27 through November 5, 2009, Leadership Meetings
in Barrow, Wainwright, Point Lay, and Kotzebue. Meetings with Native
Village of Point Hope Executive Director;
December 14, 2009, meeting the NSB Wildlife Department and
members of the AEWC to discuss proposed activities, potential impacts,
and measures for mitigating impacts;
January 2010, POC meetings in Barrow, Wainwright, Point
Lay, and Point Hope;
March 22, 2010, Marine Mammal Co-Management Group Meeting;
and
April 13 - 16, 2010, Seminars presenting research work on
oil spill contingencies in Arctic environmental conditions. Statoil
took part and together with other operators brought Norwegian and
international researchers to Anchorage, Barrow, and Kotzebue to present
results from this research project (also called the SINTEF JIP study).
Statoil states that consultation, both formal and informal, will
continue before, during and after the 2010 seismic survey activities. A
final POC that documents all consultations with community leaders,
subsistence users groups, individual subsistence users, and community
members will be submitted to NMFS, USFWS, and MMS upon completion of
consultation. The final POC will include feedback from the Leadership
Meetings and POC meetings. Statoil will continue to document all
consultation with the communities and subsistence stakeholders.
[[Page 32398]]
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. These measures, plans, and
programs will be implemented by Statoil during its 2010 open water
marine seismic survey in the Chukchi Sea to monitor and mitigate
potential impacts to subsistence users and resources. The mitigation
measures Statoil has adopted and will implement during 2010 are listed
and discussed below.
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 seismic survey 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. Statoil plans to have one major crew change which will
take place in Nome, AK, and 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.
Unmitigable Adverse Impact Analysis and Preliminary Determination
NMFS has preliminarily determined that Statoil's proposed 2010 open
water marine seismic 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 marine
seismic survey site. Based on these factors, Statoil's Chukchi Sea
seismic 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 marine seismic
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 marine seismic 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 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)
NMFS is currently preparing an Environmental Assessment, pursuant
to NEPA, to determine whether or not this proposed activity may have a
significant effect on the human environment. This analysis will be
completed prior to the issuance or denial of the IHA.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
authorize the take of marine mammals incidental to Statoil's 2010 open
water seismic survey in the Chukchi Sea, Alaska, provided the
previously mentioned mitigation, monitoring, and reporting requirements
are incorporated.
Dated: June 2, 2010.
James H. Lecky,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2010-13753 Filed 6-7-10; 8:45 am]
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