[Federal Register Volume 77, Number 237 (Monday, December 10, 2012)]
[Notices]
[Pages 73434-73451]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2012-29740]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XC374
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Seismic Survey in Cook Inlet, AK
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 Apache Alaska Corporation
(Apache) for an Incidental Harassment Authorization (IHA) to take
marine mammals, by harassment, incidental to a proposed 3D seismic
survey in Cook Inlet, Alaska, between January 2013 and January 2014.
Pursuant to the Marine Mammal Protection Act (MMPA), NMFS requests
comments on its proposal to issue an IHA to Apache to take, by Level B
harassment only, five species of marine mammals during the specified
activity.
DATES: Comments and information must be received no later than January
9, 2013.
ADDRESSES: Comments on the application should be addressed to Michael
Payne, Chief, Permits and Conservation 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 email
comments sent to addresses other than the one provided here. Comments
sent via email, 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.
An electronic 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: Brian D. Hopper, Office of Protected
Resources, NMFS, (301) 427-8401.
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 June 15, 2012, from Apache for the
taking, by harassment, of marine mammals incidental to a 3D seismic
survey program in Cook Inlet, Alaska. This is the second IHA
application NMFS has received from Apache for takes of marine mammals
incidental to conducting a seismic survey in Cook Inlet. On April 30,
2012, NMFS issued a one-year IHA to Apache for their first season of
seismic acquisition in Cook Inlet (77 FR 27720). Except for the
location and the size of the survey area, the activities proposed for
the second survey season are essentially the same as those conducted
during the first season.
The proposed 3D seismic surveys would employ the use of two source
vessels. Each source vessel would be equipped with compressors and 2400
in\3\ air gun arrays, as well as additional lower-powered and higher
frequency survey equipment for collecting bathymetric and shallow sub-
bottom data. In addition, one source vessel would be equipped with a
440 in\3\ shallow water air gun array, which it can deploy at high tide
in the intertidal area in less than 1.8 m of water. The proposed survey
would take place in Cook Inlet, and during the second survey season
Apache anticipates completing ~1,010 km\2\ of seismic acquisition in an
area that extends from just south of Anchor Point along the east coast
extending up to Point Possession and along the west coast from the
[[Page 73435]]
McArthur River up to the Beluga river, in water depths of 0-128 m (0-
420 ft).
In Area 2, Apache intends to mobilize crews and equipment in
January 2012 in order to be ready to conduct offshore/transition
(intertidal) zone marine surveys in March-April 2013, but could
commence sooner if weather conditions permit. Nearshore areas adjacent
to uplands and offshore areas will be surveyed between April and
September 2013. Impacts to marine mammals may occur from noise produced
from active acoustic sources (primarily air guns) used in the surveys.
Description of the Specified Activity
In 2010, Apache acquired over 300,000 acres of oil and gas leases
in Cook Inlet with the primary objective to explore for and develop oil
fields. In the spring of 2011, Apache conducted a seismic test program
to evaluate the feasibility of using new nodal (i.e., no cables)
technology seismic recording equipment for operations in the Cook Inlet
environment and to test various seismic acquisition parameters to
finalize the design for a 3D seismic program in Cook Inlet. The test
program took place in late March 2011 and results indicated that the
nodal technology was feasible in the Cook Inlet environment. Apache
proposes to conduct a phased 3D seismic survey program throughout Cook
Inlet over the course of the next three to five years. The first area
surveyed--and the subject of the IHA issued in April 2012--was located
in mid-Cook Inlet extending along the west coast from the Big River up
to south of the Beluga River, and on the east coast from Salamantof on
the Kenai peninsula to 4.4 miles north of the Swanson River. The second
area to be surveyed--and the subject of this IHA--would cover a lower
portion of Cook Inlet, but also includes all of Area 1.
The proposed operations are essentially the same as those that were
conducted in Area 1 under the IHA for the first seismic season. The
proposed operations would again be performed from multiple vessels.
Apache would employ the use of two source vessels. Each source vessel
would be equipped with compressors and 2400 in\3\ air gun arrays. In
addition, one source vessel would be equipped with a 440 in\3\ shallow
water air gun array, which it can deploy at high tide in the intertidal
area in less than 1.8 m of water. Three shallow draft vessels would
support cable/nodal deployment and retrieval operations, and one
mitigation/chase vessel would be used, which would also provide
berthing for the Protected Species Observers (PSOs). Finally, two
smaller jet boats would be used for personnel transport and node
support in the extremely shallow water of the intertidal area. For
additional information, such as vessel specifications, see Apache's
application.
Acquiring ~1,010 km\2\ would take approximately 160 days to
complete over the course of 8-9 months. Apache anticipates conducting
survey operations 24 hours per day. During each 24 hour period, seismic
operations would be active; however air guns would only be used for
approximately 2.5 hours during each of the slack tide periods. There
are approximately four slack tide periods in a 24-hour day, therefore,
air gun operations would be active during approximately 10-12 hours per
day, if weather conditions allow.
3D Seismic Surveys
Seismic surveys are designed to collect bathymetric and sub-
seafloor data that allow the evaluation of potential shallow faults,
gas zones, and archeological features at prospective exploration
drilling locations. Data are typically collected using multiple types
of acoustic equipment. During the surveys, Apache proposes to use the
following in-water acoustic sources: two 2400 in\3\ air gun arrays; a
single 440 in\3\ air gun array; a 10 in\3\ air gun; a Scout Ultra-Short
Baseline (USBL) Transceiver; and a Lightweight Release (LR) USBL
Transponder. Apache successfully measured the sounds produced by the
air guns and pingers during a 2D test program conducted in March 2011
and found levels to be consistent with the modeled mitigation threshold
levels (180 dB for cetaceans, 190 dB for pinnipeds); therefore, a sound
source verification study would not be included in the proposed 3D
seismic survey.
In addition, Apache plans to detonate 4 kg of Orica OSX Pentolite
explosives onshore to acquire data. Except for the explosives, the
operating frequencies and estimated source levels of the survey
equipment are provided below.
(1) Airguns
The 2400 in\3\ air gun arrays and the 440 in\3\ air gun array would
be used to obtain geological data during the survey. The acoustic
source level of the 2400 in\3\ air gun array was predicted using an air
gun array source model (AASM) developed by JASCO. The AASM simulates
the expansion and oscillation of the air bubbles generated by each air
gun within a seismic array, taking into account pressure interaction
effects between bubbles from different air guns. It includes effects
from surface-reflected pressure waves, heat transfer from the bubbles
to the surrounding water, and the movements of bubbles due to their
buoyancy. The model outputs high-resolution air gun pressure signatures
for each air gun, which are superimposed with the appropriate time
delays to yield the overall array source signature in any direction.
The 190, 180, and 160 dBrms re 1 [micro]Pa isopleths were
estimated at three different water depths (5 m, 25 m, and 45 m) for
nearshore surveys and at 80 m for channel surveys. The distances to
these thresholds for the nearshore survey locations are provided in
Table 1 and correspond to the three transects modeled at each site in
the onshore, offshore, and parallel to shore directions. The distances
to the thresholds for the channel survey locations are provided in
Table 2 and correspond to the broadside and endfire directions. The
areas ensonified to the 160 dB isopleth for the nearshore survey are
provided in Table 3. The area ensonifed to the 160 dB isopleth for the
channel survey is 389 km\2\.
Table 1--Distances to Sound Thresholds for the Nearshore Surveys
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Distance in
Water depth Distance in Distance in the parallel
Threshold (dB re 1 [micro]Pa) at source the onshore the offshore to shore
location (m) direction direction direction
(km) (km) (km)
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160............................................. 5 0.85 3.91 1.48
25 4.70 6.41 6.34
45 5.57 4.91 6.10
180............................................. 5 0.46 0.60 0.54
25 1.06 1.07 1.42
45 0.70 0.83 0.89
[[Page 73436]]
190............................................. 5 0.28 0.33 0.33
25 0.35 0.36 0.44
45 0.10 0.10 0.51
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Table 2--Distance to Sound Thresholds for the Channel Surveys
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Distance in Distance in
Water depth the broadside the endfire
Threshold (dB re 1 [mu]Pa) at source direction direction
location (m) (km) (km)
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160............................................................. 80 4.24 4.89
180............................................................. 80 0.91 0.98
190............................................................. 80 0.15 0.18
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Table 3--Areas Ensonified to 160 dB for Nearshore Surveys
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Area ensonifed
Nearshore survey depth Depth range (m) to 160 dB
classification (km\2\)
------------------------------------------------------------------------
Shallow............................. 5-21 346
Mid-Depth........................... 21-38 458
Deep................................ 38-54 455
------------------------------------------------------------------------
(2) Pingers
These instruments would be operated during survey operations to
determine the exact position of the nodes after they have been placed
on the seafloor. One device, the Scout Ultra-Short Baseline
Transceiver, operates at frequencies between 33 and 55 kHz with a
source level of 188 dB re 1 [mu]Pa at 1 m. The other device, an LR
Ultra-Short Baseline Transponder, operates at a frequency of 35-50 kHz
at a source level of 185 dB re 1 [mu]Pa at 1 m. With respect to these
two sources, Apache provided and NMFS relied on the distances to the
Level B harassment thresholds estimated for the ``louder'' of the two;
therefore, assuming a simple spreading loss of 20 log R (where R is
radius), with a source level of 188 dB the distance to the 190, 180,
and 160 dB isopleths would be 1, 3, and 25 m, respectively. Another
technique for locating the nodes in deeper water is called Ocean Bottom
Receiver Location, which uses a small volume air gun (10 in\3\) firing
parallel to the node line.
(3) Detonations of Explosives
The onshore areas would be surveyed using explosives as the sound
source. Seismic surveys on land use ``shot holes'' that are drilled
every 50 m along source lines and are oriented perpendicular to the
receiver lines and parallel to the coast. At each source location,
Apache would drill to the prescribed hole depth of approximately 10 m
and load it with 4 kg of explosives. The hole would then capped with a
``smart cap'' that makes it impossible to detonate the explosive
without the proper detonator. During a 2D test program conducted in
March 2011, Apache deployed acoustic recorders to measure underwater
sound produced by land-based explosives; however, the resulting
measurements were inconclusive and Apache conducted a sound source
verification (SSV) study in September 2011 to characterize the
underwater received sound levels and determine if marine mammal
monitoring would be required for future onshore operations. The SSV
study found that in-water noise generated from explosive detonations
onshore did not rise to a level that would result in the harassment of
marine mammals in the water.
Description of Marine Mammals in the Area of the Specified Activity
The marine mammal species under NMFS's jurisdiction that could
occur near operations in Cook Inlet include three cetacean species, all
odontocetes (toothed whales): beluga whale (Delphinapterus leucas),
killer whale (Orcinus orca), and harbor porpoise (Phocoena phocoena),
and two pinniped species: harbor seal (Phoca vitulina richardsi) and
Steller sea lions (Eumetopias jubatus). The marine mammal species that
is likely to be encountered most widely (in space and time) throughout
the period of the planned surveys is the harbor seal.
Of the five marine mammal species likely to occur in the proposed
marine survey area, only Cook Inlet beluga whales and Steller sea lions
are listed as endangered under the ESA (Steller sea lions are listed as
two distinct population segments (DPSs), an eastern and a western DPS;
the relevant DPS in Cook Inlet is the western DPS). These species are
also designated as ``depleted'' under the MMPA. Despite these
designations, Cook Inlet beluga whales and the western DPS of Steller
sea lions have not made significant progress towards recovery. The Cook
Inlet population of beluga whales has been decreasing at a rate of 1.5
percent annually for nearly a decade (Allen and Angliss, 2010). With
respect to Steller sea lions, results of aerial surveys conducted in
2008 (Fritz et al., 2008) confirmed that the recent (2004-2008) overall
trend in the western population of adult and juvenile Steller sea lions
in Alaska is stable or possibly in decline; however, there continues to
be considerable regional variability in recent trends. Pursuant to the
ESA, critical habitat has been designated for Cook Inlet beluga whales
and Steller sea lions. The proposed action falls within critical
habitat designated in Cook Inlet for beluga whales, but is not within
[[Page 73437]]
critical habitat designated for Steller sea lions. The portion of
beluga whale critical habitat--identified as Area 2 in the critical
habitat designation--where the seismic survey will occur is located
south of the Area 1 critical habitat where belugas are particularly
vulnerable to impacts due to their high seasonal densities and the
biological importance of the area for foraging, nursery, and predator
avoidance. Area 2 is largely based on dispersed fall and winter feeding
and transit areas in waters where whales typically appear in smaller
densities or deeper waters (76 FR 20180, April 11, 2011).
Cetaceans
Beluga Whales--Cook Inlet beluga whales reside in Cook Inlet year-
round although their distribution and density changes seasonally.
Factors that are likely to influence beluga whale distribution within
the inlet include prey availability, predation pressure, sea-ice cover,
and other environmental factors, reproduction, sex and age class, and
human activities (Rugh et al., 2000; NMFS 2008). Seasonal movement and
density patterns as well as site fidelity appear to be closely linked
to prey availability, coinciding with seasonal salmon and eulachon
concentrations (Moore et al., 2000). For example, during spring and
summer, beluga whales are generally concentrated near the warmer waters
of river mouths where prey availability is high and predator occurrence
in low (Huntington 2000; Moore et al., 2000). During the winter
(November to April), belugas disperse throughout the upper and mid-
inlet areas, with animals found between Kalgin Island and Point
Possession (Rugh et al., 2000). During these months, there are
generally fewer observations of beluga whales in the Anchorage and Knik
Arm area (NMML 2004; Rugh et al., 2004).
Beluga whales use several areas of the upper Cook Inlet for
repeated summer and fall feeding. The primary hotspots for beluga
feeding include the Big and Little Susitna rivers, Eagle Bay to Eklutna
River, Ivan Slough, Theodore River, Lewis River, and Chickaloon River
and Bay (NMFS 2008). Availability of prey species appears to be the
most influential environmental variable affecting Cook Inlet beluga
whale distribution and relative abundance (Moore et al. 2000). The
patterns and timing of eulachon and salmon runs have a strong influence
on beluga whale feeding behavior and their seasonal movements (Nemeth
et al., 2007; NMFS 2008). The presence of prey species may account for
the seasonal changes in beluga group size and composition (Moore et
al., 2000). Aerial and vessel-based monitoring conducted by Apache
during the March 2011 2D test program in Cook Inlet reported 33 beluga
sightings. One of the sightings was of a large group (~25 individuals
on March 27, 2011) of feeding/milling belugas near the mouth of the
Drift River. Also on March 27, 2011, PSOs onboard the M/V Dreamcatcher
reported a group of seven beluga whales approximately 0.5 nm from the
vessel. Land-based PSOs were able to observe this group of beluga
whales for approximately 2.5 hrs. A single beluga whale was observed
near the mouth of the Drift River by the aerial-based monitors on March
28, 2011, prior to the seismic ramp-up period. If belugas are present
during the late summer/early fall, they are more likely to occur in
shallow areas near river mouths in upper Cook Inlet. For example, no
beluga whales were sighted in Trading Bay during the SSV conducted in
September 2011 because during this time of year they are more likely to
be in the upper regions of Cook Inlet. Expected densities were
calculated from the annual aerial surveys conducted by NMFS between
2000 and 2011 (Rugh et al. 2000, 2001, 2002, 2003, 2004, 2005, 2006,
2007; Shelden et al. 2008, 2009, 2010; Hobbs et al. 2011). Those
densities are presented below in Table 5.
Killer Whales--In general, killer whales are rare in upper Cook
Inlet, where transient killer whales are known to feed on beluga whales
and resident killer whales are known to feed on anadromous fish
(Shelden et al., 2003). The availability of these prey species largely
determines the likeliest times for killer whales to be in the area.
Between 1993 and 2004, 23 sightings of killer whales were reported in
the lower Cook Inlet during aerial surveys by Rugh et al. (2005).
Surveys conducted over a span of 20 years by Shelden et al. (2003)
reported 11 sightings in upper Cook Inlet between Turnagain Arm,
Susitna Flats, and Knik Arm. No killer whales were spotted during
recent surveys by Funk et al. (2005), Ireland et al. (2005), Brueggeman
et al. (2007a, 2007b, 2008), or Prevel Ramos et al. (2006, 2008).
Eleven killer whale strandings have been reported in Turnagain Arm, six
in May 1991 and five in August 1993. Therefore, very few killer whales,
if any, are expected to approach or be in the vicinity of the action
area.
Harbor Porpoise--The most recent estimated density for harbor
porpoises in Cook Inlet is 7.2 per 1,000 km\2\ (Dahlheim et al., 2000)
indicating that only a small number use Cook Inlet. Harbor porpoise
have been reported in lower Cook Inlet from Cape Douglas to the West
Foreland, Kachemak Bay, and offshore (Rugh et al., 2005). Small numbers
of harbor porpoises have been consistently reported in upper Cook Inlet
between April and October, except for a recent survey that recorded
higher than usual numbers. Prevel Ramos et al. (2008) reported 17
harbor porpoises from spring to fall 2006, while other studies reported
14 in the spring of 2007 (Brueggeman et al. 2007) and 12 in the fall
(Brueggeman et al. 2008). During the spring and fall of 2007, 129
harbor porpoises were reported between Granite Point and the Susitna
River; however, the reason for the increase in numbers of harbor
porpoise in the upper Cook Inlet remains unclear and the disparity with
the result of past sightings suggests that it may be an anomaly. The
spike in reported sightings occurred in July, which was followed by
sightings of 79 harbor porpoises in August, 78 in September, and 59 in
October, 2007. It is important to note that the number of porpoises
counted more than once was unknown, which suggests that the actual
numbers are likely smaller than those reported. In addition, recent
passive acoustic research in Cook Inlet by the Alaska Department of
Fish and Game and the National Marine Mammal Laboratory have indicated
that harbor porpoises occur in the area more frequently than previously
thought, particularly in the West Foreland area in the spring (NMFS
2011); however overall numbers are still unknown at this time.
Pinnipeds
Two species of pinnipeds may be encountered in Cook Inlet: harbor
seal and Steller sea lion.
Harbor Seals--Harbor seals inhabit the coastal and estuarine waters
of Cook Inlet. In general, harbor seals are more abundant in lower Cook
Inlet than in upper Cook Inlet, but they do occur in the upper inlet
throughout most of the year (Rugh et al. 2005). Harbor seals are non-
migratory; their movements are associated with tides, weather, season,
food availability, and reproduction. The major haulout sites for harbor
seals are located in lower Cook Inlet and their presence in the upper
inlet coincides with seasonal runs of prey species. For example, harbor
seals are commonly observed along the Susitna River and other
tributaries along upper Cook Inlet during the eulachon and salmon
migrations (NMFS 2003). During aerial surveys of upper Cook Inlet in
2001, 2002, and 2003, harbor seals were observed 24 to 96 km south-
southwest of Anchorage at the Chickaloon, Little Susitna, Susitna,
Ivan, McArthur, and
[[Page 73438]]
Beluga Rivers (Rugh et al., 2005). During the 2D test program in March
2011, two harbor seals were observed by vessel-based PSOs. On March 25,
2011, one harbor seal was observed approximately 400 m from the M/V
Miss Diane. At the time of the observation, the vessel was operating
the positioning pinger and PSOs instructed the operator to implement a
shut-down. The pinger was shut down for 30 minutes while PSO monitored
the area and re-started the device when the animal was not sighted
again during the 30 minute site clearing protocol. No unusual behaviors
were reported during the time the animal was observed. The second
harbor seal was observed on March 26, 2011, by vessel-based PSO onboard
the M/V Dreamcatcher approximately 4260 m from the source vessel, which
was operating the 10 in\3\ air gun at the time. The animal was well
outside of the 160 dB zone (330 m for the 10 in\3\ air gun) and no
unusual behaviors were observed. Many harbor seals were observed during
the 3D seismic survey conducted under the April 2012 IHA, especially
when survey operations were conducted close to shore. NMFS and Apache
do not anticipate encountering large haulouts of seals in Area 2--the
closest haulout site to the action area is located on Kalgin Island,
which is approximately 22 km away from the McArthur River--but we do
expect to see curious individual harbor seals; especially during large
fish runs in the various rivers draining into Cook Inlet.
Steller Sea Lion--Two separate stocks of Steller sea lions are
recognized within U.S. waters: an eastern U.S. stock, which includes
animals east of Cape Suckling, Alaska; and a western U.S. stock, which
includes animals west of Cape Suckling (NMFS 2008). Individuals in Cook
Inlet are considered part of the western U.S. stock, which is listed as
endangered under the ESA. Steller sea lions primarily occur in lower,
rather than upper Cook Inlet and are rarely sighted north of Nikiski on
the Kenai Peninsula. Haul-outs and rookeries are located near Cook
Inlet at Gore Point, Elizabeth Island, Perl Island, and Chugach Island
(NMFS 2008). No Steller seal lion haul-outs or rookeries are located in
the vicinity of the proposed seismic survey. Furthermore, no sightings
of Steller sea lions were reported by Apache during the 2D test program
in March 2011. During the 3D seismic survey, one Steller sea lion was
observed from the M/V Dreamcatcher on August 18, 2012, during a period
when the air guns were not active. Although Apache has requested takes
of Steller sea lions, Steller sea lions would be rare in the action
area during seismic survey operations.
Apache'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 2011 SAR is available at: http://www.nmfs.noaa.gov/pr/pdfs/sars/ak2011.pdf.
Potential Effects of the Specified Activity on Marine Mammals
Operating active acoustic sources, such as air gun arrays, has the
potential for adverse effects on marine mammals.
Potential Effects of Air Gun Sounds on Marine Mammals
The effects of sounds from air gun 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,
often depending on species and contextual factors, and can be
categorized as follows (based on Richardson et al. 1995):
(1) Tolerance
Numerous studies have shown that pulsed sounds from air guns are
often readily detectable in the water at distances of many kilometers.
Numerous studies have also shown that marine mammals at distances more
than a few kilometers from operating survey vessels often show no
apparent response. That is often true even in cases when the pulsed
sounds must be readily audible to the animals based on measured
received levels and the hearing sensitivity of that mammal group. In
general, pinnipeds and small odotocetes (toothed whales) seem to be
more tolerant of exposure to air gun pulses than baleen whales.
Although various toothed whales, and (less frequently) pinnipeds have
been shown to react behaviorally to air gun pulses under some
conditions, at other times, mammals of both types have shown no overt
reactions. For example, the available evidence also indicates that Cook
Inlet beluga whales are less impacted behaviorally by anthropogenic
sounds compared to marine mammals in more pristine acoustic
environments (e.g., the Beaufort Sea) given the Cook Inlet population's
greater experience with anthropogenic sounds.
(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 have the potential to be biologically significant if the
change affects growth, survival, or reproduction. Examples of
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
Cessation of 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 a received level of 160 dB re 1 [mu]Pa to
estimate the onset threshold for marine mammal behavioral harassment
for impulse noises (such as air gun pulses). As explained below, NMFS
has determined that use of this threshold is appropriate for Apache's
IHA considering the scientific literature pertaining to this issue and
the evidence specific to the marine mammal species and populations in
question.
(3) Masking
Marine mammals use acoustic signals for a variety of purposes,
which differ among species, but include communication between
individuals, navigation, foraging, reproduction, and learning about
their environment (Erbe and Farmer, 2000; Tyack, 2000). Masking, or
auditory interference,
[[Page 73439]]
generally occurs when sounds in the environment are louder than, and of
a similar frequency as, auditory signals an animal is trying to
receive. Masking is a phenomenon that affects animals that are trying
to receive acoustic information about their environment, including
sounds from other members of their species, predators, prey, and sounds
that allow them to orient in their environment. Masking these acoustic
signals can disturb the behavior of individual animals, groups of
animals, or entire populations.
Masking occurs when noise and signals (that the animal utilizes)
overlap at both spectral and temporal scales. For the air gun noise
generated from the proposed seismic surveys, noise will consist of low
frequency (under 500 Hz) pulses with extremely short durations (less
than one second). 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 near the noise source due to the brief duration of
these pulses and relatively longer silence between air gun shots
(approximately 12 seconds). However, at long distances (over tens of
kilometers away), due to multipath propagation and reverberation, the
durations of air gun pulses can be ``stretched'' to seconds with long
decays (Madsen et al. 2006), although the intensity of the noise is
greatly reduced.
This 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);
however, no baleen whales are expected to occur within the action area.
Marine mammals are thought to be able to compensate for masking by
adjusting their acoustic behavior by shifting call frequencies, and/or
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 could 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.
Researchers have studied TTS in certain captive odontocetes and
pinnipeds exposed to strong sounds (reviewed in Southall et al., 2007).
However, there has been no specific documentation of TTS let alone
permanent hearing damage, i.e., permanent threshold shift (PTS), in
free-ranging marine mammals exposed to sequences of airgun pulses
during realistic field conditions.
Temporary Threshold Shift--TTS is the mildest form of hearing
impairment that can occur during exposure to a strong sound (Kryter,
1985). While experiencing TTS, the hearing threshold rises and a sound
must be stronger in order to be heard. At least in terrestrial mammals,
TTS can last from minutes or hours to (in cases of strong TTS) days.
For sound exposures at or somewhat above the TTS threshold, hearing
sensitivity in both terrestrial and marine mammals recovers rapidly
after exposure to the noise ends. Few data on sound levels and
durations necessary to elicit mild TTS have been obtained for marine
mammals, and none of the published data concern TTS elicited by
exposure to multiple pulses of sound. Available data on TTS in marine
mammals are summarized in Southall et al. (2007).
To avoid the potential for injury, NMFS (1995, 2000) concluded that
cetaceans and pinnipeds should not be exposed to pulsed underwater
noise at received levels exceeding 180 and 190 dB re 1 [mu]Pa (rms),
respectively. The 180 and 190 dB (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. NMFS
also assumes that cetaceans and pinnipeds exposed to levels exceeding
160 dB re 1 [mu]Pa (rms) may experience Level B harassment.
For toothed whales, researchers have derived TTS information for
odontocetes from studies on the bottlenose dolphin and beluga. The
experiments show that exposure to a single impulse at a received level
of 207 kPa (or 30 psi, p-p), which is equivalent to 228 dB re 1 Pa (p-
p), resulted in a 7 and 6 dB TTS in the beluga whale at 0.4 and 30 kHz,
respectively. Thresholds returned to within 2 dB of the pre-exposure
level within 4 minutes of the exposure (Finneran et al., 2002). For the
one harbor porpoise tested, the received level of airgun sound that
elicited onset of TTS was lower (Lucke et al., 2009). If these results
from a single animal are representative, it is inappropriate to assume
that onset of TTS occurs at similar received levels in all odontocetes
(cf. Southall et al., 2007). Some cetaceans apparently can incur TTS at
considerably lower sound exposures than are necessary to elicit TTS in
the beluga or bottlenose dolphin.
In pinnipeds, researchers have not measured TTS thresholds
associated with exposure to brief pulses (single or multiple) of
underwater sound. Initial evidence from more prolonged (non-pulse)
exposures suggested that some pinnipeds (harbor seals in particular)
incur TTS at somewhat lower received levels than do small odontocetes
exposed for similar durations (Kastak et al., 1999, 2005; Ketten et
al., 2001). The TTS threshold for pulsed sounds has been indirectly
estimated as being an SEL of approximately 171 dB re 1
[micro]Pa\2\[middot]s (Southall et al., 2007) which would be equivalent
to a single pulse with a received level of approximately 181 to 186 dB
re 1 [micro]Pa (rms), or a series of pulses for which the highest rms
values are a few dB lower. Corresponding values for California sea
lions and northern elephant seals are likely to be higher (Kastak et
al., 2005).
No cases of TTS are expected as a result of Apache's proposed
activities given the strong likelihood that marine mammals would avoid
the approaching air guns (or vessel) before being exposed to levels
high enough for there to be any possibility of TTS, and the mitigation
measures proposed to be implemented during the survey described later
in this document.
Permanent Threshold Shift--When PTS occurs, there is physical
damage to the sound receptors in the ear. In severe cases, there can be
total or partial deafness, whereas in other cases, the animal has an
impaired ability to hear sounds in specific frequency ranges
[[Page 73440]]
(Kryter, 1985). There is no specific evidence that exposure to pulses
of airgun sound can cause PTS in any marine mammal, even with large
arrays of airguns. However, given the possibility that mammals close to
an airgun array might incur at least mild TTS, there has been further
speculation about the possibility that some individuals occurring very
close to airguns might incur PTS (e.g., Richardson et al., 1995;
Gedamke et al., 2008). Single or occasional occurrences of mild TTS are
not indicative of permanent auditory damage, but repeated or (in some
cases) single exposures to a level well above that causing TTS onset
might elicit PTS.
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 (Southall et al., 2007). PTS might occur at a
received sound level at least several dBs above that inducing mild TTS
if the animal were exposed to strong sound pulses with rapid rise
times. Based on data from terrestrial mammals, a precautionary
assumption is that the PTS threshold for impulse sounds (such as airgun
pulses as received close to the source) is at least 6 dB higher than
the TTS threshold on a peak-pressure basis, and probably greater than 6
dB (Southall et al., 2007).
Given the higher level of sound necessary to cause PTS as compared
with TTS, it is considerably less likely that PTS would occur during
the proposed seismic survey in Cook Inlet. Cetaceans generally avoid
the immediate area around operating seismic vessels, as do some other
marine mammals. Some pinnipeds show avoidance reactions to airguns, but
their avoidance reactions are generally not as strong or consistent as
those of cetaceans, and occasionally they seem to be attracted to
operating seismic vessels (NMFS, 2010).
(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 air guns, and beaked whales do not occur in the proposed
project area. In addition, marine mammals that show behavioral
avoidance of seismic vessels, including most baleen whales, some
odontocetes (including belugas), and some pinnipeds, are especially
unlikely to incur non-auditory impairment or other physical effects.
The distances to the 180 and 190 dB thresholds for the air gun array
proposed to be used by Apache are provided above in Tables 1 and 2.
Therefore, it is unlikely that such effects would occur during
Apache's proposed surveys given the brief duration of exposure and the
planned monitoring and mitigation measures described later in this
document.
(6) Stranding and Mortality
Marine mammals close to underwater detonations of high explosive
can be killed or severely injured, and the auditory organs are
especially susceptible to injury (Ketten et al. 1993; Ketten 1995). Air
gun pulses are less energetic and their peak amplitudes have slower
rise times. To date, there is no evidence that serious injury, death,
or stranding by marine mammals can occur from exposure to air gun
pulses, even in the case of large air gun 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, including in the
Federal Register notice announcing the IHA for Apache's first seismic
survey in 2012, 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), 71
FR 49418 (August 23, 2006), and 77 FR 27720 (May 11, 2012).
It should be noted that strandings related to sound exposure have
not been recorded for marine mammal species in Cook Inlet. Beluga whale
strandings in Cook Inlet are not uncommon; however, these events often
coincide with extreme tidal fluctuations (``spring tides'') or killer
whale sightings (Shelden et al., 2003). For example, in August 2012, a
group of Cook Inlet beluga whales stranded in the mud flats of
Turnagain Arm during low tide and were able to swim free with the flood
tide. No strandings or marine mammals in distress were observed during
the 2D test survey conducted by Apache in March 2011 and none were
reported by Cook Inlet inhabitants. Furthermore, no strandings were
reported during seismic survey operations conducted under the April
2012 IHA. As a result, NMFS does not expect any marine mammals will
incur serious injury or mortality in Cook Inlet or strand as a result
of the proposed seismic survey.
Potential Effects From Pingers on Marine Mammals
Active acoustic sources other than the airguns have been proposed
for Apache's 2013 seismic survey in Cook Inlet. The specifications for
the pingers (source levels and frequency ranges) were provided earlier
in this document. In general, the potential effects of this equipment
on marine mammals are similar to those from the airguns, except the
magnitude of the impacts is expected to be much less due to the lower
intensity of the source.
Potential Effects From Vessels and Vessel Noise on Marine Mammals
Vessel activity and noise associated with vessel activity will
temporarily increase in the action area during Apache's seismic survey
as a result of the operation of eight vessels. To minimize the effects
of vessels and noise associated with vessel activity, Apache will
follow NMFS' Marine Mammal Viewing Guidelines and Regulations and will
alter heading or speed if a marine mammal gets too close to a vessel.
In addition, vessels will be operating at slow speed (2-4 knots) when
conducting surveys and in a purposeful manner to and from work sites in
as direct a route as possible. Marine mammal monitoring observers and
passive acoustic devices will alert vessel captains as animals are
detected to ensure safe and effective measures are applied to avoid
coming into direct contact with marine mammals. Therefore, NMFS neither
anticipates nor authorizes takes of marine mammals from ship strikes.
Odontocetes, such as beluga whales, killer whales, and harbor
porpoises, often show tolerance to vessel activity; however, they may
react at long distances if they are confined by ice, shallow water, or
were previously harassed by vessels (Richardson, 1995). Beluga whale
response to vessel noise varies greatly from tolerance to extreme
sensitivity depending on the activity of the whale and previous
experience with vessels (Richardson, 1995). Reactions to vessels
depends on whale activities and experience, habitat, boat type, and
boat behavior (Richardson, 1995) and may
[[Page 73441]]
include behavioral responses, such as altered headings or avoidance
(Blane and Jaakson, 1994; Erbe and Farmer, 2000); fast swimming;
changes in vocalizations (Lesage et al., 1999; Scheifele et al., 2005);
and changes in dive, surfacing, and respiration patterns.
There are few data published on pinniped responses to vessel
activity, and most of the information is anecdotal (Richardson, 1995).
Generally, sea lions in water show tolerance to close and frequently
approaching vessels and sometimes show interest in fishing vessels.
They are less tolerant when hauled out on land; however, they rarely
react unless the vessel approaches within 100-200 m (330-660 ft;
reviewed in Richardson, 1995).
The addition of eight vessels and noise due to vessel operations
associated with the seismic survey would not be outside the present
experience of marine mammals in Cook Inlet, although levels may
increase locally. Given the large number of vessels in Cook Inlet and
the apparent habituation to vessels by Cook Inlet beluga whales and the
other marine mammals that may occur in the area, vessel activity and
noise is not expected to have effects that could cause significant or
long-term consequences for individual marine mammals or their
populations.
Potential Effects From Aircraft Noise on Marine Mammals
Apache plans to utilize the crew helicopter to conduct aerial
surveys near river mouths in order to identify locations or
congregations of beluga whales and other marine mammals prior to the
commencement of operations. The helicopter will not be used every day,
but will be used for surveys near river mouths. Aerial surveys will fly
at an altitude of 305 m (1,000 ft) when practicable and weather
conditions permit. In the event of a marine mammal sighting, aircraft
will try to maintain a radial distance of 457 m (1,500 ft) from the
marine mammal(s). Aircraft will avoid approaching marine mammals from
head-on, flying over or passing the shadow of the aircraft over the
marine mammals.
Studies on the reactions of cetaceans to aircraft show little
negative response (Richardson et al., 1995). In general, reactions
range from sudden dives and turns and are typically found to decrease
if the animals are engaged in feeding or social behavior. Whales with
calves or in confined waters may show more of a response. Generally
there has been little or no evidence of marine mammals responding to
aircraft overflights when altitudes are at or above 1,000 ft, based on
three decades of flying experience in the Arctic (NMFS, unpublished
data). Based on long-term studies that have been conducted on beluga
whales in Cook Inlet since 1993, NMFS expect that there will be no
effects of this activity on beluga whales or other cetaceans. No change
in beluga swim directions or other noticeable reactions have been
observed during the Cook Inlet aerial surveys flown from 600 to 800 ft.
(e.g., Rugh et al., 2000). By applying the operational requirements
discussed above, sound levels underwater are not expected to reach
NMFS' harassment thresholds.
The majority of observations of pinnipeds reacting to aircraft
noise are associated with animals hauled out on land or ice. There are
very little data describing the reactions of pinnipeds in water to
aircraft (Richardson et al., 1995). In the presence of aircraft,
pinnipeds hauled out for pupping or molting generally became alert and
then rushed or slipped (when on ice) into the water. Stampedes often
result from this response and may increase pup mortality due to
crushing or an increase rate of pup abandonment. The greatest reactions
from hauled out pinnipeds were observed when low flying aircrafts
passed directly above the animal(s) (Richardson et al., 1995). Although
noise associated with aircraft activity could cause hauled out
pinnipeds to rush into the water, there are no known haul out sites in
the vicinity of the survey site.
Therefore, the operation of aircraft during the seismic survey is
not expected to have effects that could cause significant or long-term
consequences for individual marine mammals or their populations. To
minimize the noise generated by aircraft, Apache will follow NMFS'
Marine Mammal Viewing Guidelines and Regulations found at http://www.alaskafisheries.noaa.gov/protectedresources/mmv/guide.htm.
Land-Based Explosives
The onshore component of the seismic survey involves the
underground detonation of explosive devices to acquire seismic data on
land. Because underwater sound levels associated with the land-based
explosives were previously unknown, in September 2011, Apache conducted
a SSV study, which found that marine mammals would not be exposed to
underwater sound levels that exceed the NMFS injury or harassment
thresholds.
Anticipated Effects on Marine Mammal Habitat
The primary potential impacts to marine mammal habitat 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 and are discussed below.
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).
[[Page 73442]]
Potential Impacts to the Benthic Environment
Apache's seismic survey requires the deployment of a submersible
recording system in the inter-tidal and marine zones. An autonomous
``nodal'' (i.e., no cables) system would be placed on the seafloor by
specific vessels in lines parallel to each other with a node line
spacing of 402 m. Each nodal ``patch'' would have six to eight node
lines parallel to each other. The lines generally run perpendicular to
the shoreline. An entire patch would be placed on the seafloor prior to
air gun activity. As the patches are surveyed, the node lines would be
moved either side to side or inline to the next location. Placement and
retrieval of the nodes may cause temporary and localized increases in
turbidity on the seafloor. The substrate of Cook Inlet consists of
glacial silt, clay, cobbles, pebbles, and sand (Sharma and Burrell,
1970). Sediments like sand and cobble dissipate quickly when suspended,
but finer materials like clay and silt can create thicker plumes that
may harm fish; however, the turbidity created by placing and removing
nodes on the seafloor would settle to background levels within minutes
after the cessation of activity.
In addition, seismic noise will radiate throughout the water column
from air guns and pingers until is dissipates to background levels. No
studies have demonstrated that seismic noise affects the life stages,
condition, or amount of food resources (fish, invertebrates, eggs) used
by marine mammals, except when exposed to sound levels within a few
meters of the seismic source or in few very isolated cases. Where fish
or invertebrates did respond to seismic noise, the effects were
temporary and of short duration. Consequently, disturbance to fish
species due to the activities associated with the seismic survey (i.e,
placement and retrieval of nodes and noise from sound sources) would be
short term and fish would be expected to return to their pre-
disturbance behavior once seismic survey activities cease.
Based on the preceding discussion, 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 seismic survey in Cook Inlet, Apache 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 survey activities.
Mitigation Measures Proposed in Apache's IHA Application
For the proposed mitigation measures, Apache listed the following
protocols to be implemented during its seismic survey in Cook Inlet.
(1) Operation of Mitigation Air Gun at Night
Apache proposes to conduct both daytime and nighttime operations.
Nighttime operations would only be initiated if a mitigation air gun
(typically the 10 in\3\) has been continuously operational from the
time that PSO monitoring has ceased for the day. The mitigation airgun
would operate on a longer duty cycle than the full airgun arrays,
firing every 30-45 seconds. Seismic activity would not ramp up from an
extended shut-down (i.e., when the airgun has been down with no
activity for at least 10 minutes) during nighttime operations and
survey activities would be suspended until the following day because
dedicated PSOs would not be on duty and any unseen animals may be
exposed to injurious levels of sound from the full array. At night, the
vessel captain and crew would maintain lookout for marine mammals and
would order the airgun(s) to be shut down if marine mammals are
observed in or about to enter the established safety radii.
(2) Safety and Disturbance Zones
NMFS mitigation or shutdown ``safety radii'' for limiting marine
mammal exposure to impulse sources typically correspond to the
distances within which received sound levels are >=180 dBrms
re 1 [mu]Pa for cetaceans and >=190 dBrms re 1 [mu]Pa for
pinnipeds. These safety criteria are based on an assumption that SPLs
received at levels lower than these will not injure these animals or
impair their hearing abilities. Disturbance or behavioral effects to
marine mammals from underwater sound may occur from exposure to sound
at lower SPLs, at distances greater than the safety radii (Richardson
et al., 1995). The disturbance zone is defined as the area between the
180/190 dB threshold and the 160 dB threshold where NMFS has determined
that harassment in the form of behavioral disturbance may occur.
The proposed survey would use airgun sources composed of two 2400
in\3\ airguns, a single 440 in\3\ airgun, and a single 10 in\3\ airgun.
Safety and disturbance radii for the sound levels produced by the
planned airgun configurations and pinger have been estimated (see Table
4) and would be used for mitigation purposes during the seismic survey
activities.
Table 4--Estimated Distances to Sound Thresholds
----------------------------------------------------------------------------------------------------------------
Source 190 dB 180 dB 160 dB
----------------------------------------------------------------------------------------------------------------
Pinger............................... 1 m.................... 3 m.................... 25 m
10 cui Airgun........................ 10 m................... 33 m................... 330 m
440 cui Airgun....................... NA..................... NA..................... NA
2,400 cui airgun (nearshore)......... 0.51 km................ 1.42 km................ 6.41 km
2,400 cui airgun (offshore).......... 1.18 km................ 0.98 km................ 4.89 km
----------------------------------------------------------------------------------------------------------------
In addition to the marine mammal monitoring radii described above,
pursuant to Alaska Department of Fish and Game restrictions, there
would be a 1.6 km setback of sound source points from the mouths of any
anadromous streams.
Apache also plans to use dedicated vessels to deploy and retrieve
the nodal recording system. Sounds produced by the vessels are not
expected to exceed 180 dB (rms). Therefore, mitigation related to
acoustic impacts from these activities is not expected to be necessary.
[[Page 73443]]
(3) Speed and Course Alterations
If a marine mammal is detected outside the applicable safety radius
and, based on its position and the relative motion, is likely to enter
the safety radius, changes of the vessel's speed and/or direct course
would be considered if this does not compromise operational safety. For
marine seismic surveys using large arrays, course alterations are not
typically possible. However, for the smaller air gun arrays planned
during the proposed site surveys, such changes may be possible. After
any such speed and/or course alteration is begun, the marine mammal
activities and movements relative to the survey vessel would be closely
monitored to ensure that the marine mammal does not approach within the
safety radius. If the mammal appears likely to enter the safety radius,
further mitigative actions would be taken, including a power down or
shut down of the airgun(s).
(4) Power-Downs
A power-down for mitigation purposes is the immediate reduction in
the number of operating airguns such that the radii of the 190 dB rms
and 180 dB rms zones are decreased to the extent that an observed
marine mammal(s) are not in the applicable safety zone of the full
array. During a power-down, one air gun, typically the 10 in\3\,
continues firing. Operation of the 10 in\3\ air gun decreases the
safety radii to 10 m, 33 m, and 330 m for the 190 dB, 180 dB, and 160
dB, respectively. The continued operation of one airgun is intended to
(a) alert marine mammals to the presence of the survey vessel in the
area, and (b) retain the option of initiating a ramp up to full
operations under poor visibility conditions.
The array would be immediately powered down whenever a marine
mammal is sighted approaching close to or within the applicable safety
zone of the full array, but is outside the applicable safety zone of
the single mitigation airgun. Likewise, if a mammal is already within
the safety zone when first detected, the airguns would be powered down
immediately. If a marine mammal is sighted within or about to enter the
applicable safety zone of the single mitigation airgun, it too would be
shut down (see following section).
Following a power-down, operation of the full airgun array would
not resume until the marine mammal has cleared the safety zone. The
animal would be considered to have cleared the safety zone if it:
Is visually observed to have left the safety zone of the
full array, or
Has not been seen within the zone for 15 min in the case
of pinnipeds or small odontocetes, or
Has not been seen within the zone for 30 min in the case
of large odontocetes.
(5) Shut-Downs
The operating airgun(s) would be shut down completely if a marine
mammal approaches or enters the safety radius and a power-down is not
practical or adequate to reduce exposure to less than 190 or 180 dB
rms, as appropriate. In most cases, this means the mitigation airgun
would be shut down completely if a marine mammal approaches or enters
the estimated safety radius around the single 10 in\3\ air gun while it
is operating during a power dow090Airgun activity would not resume
until the marine mammal has cleared the safety radius. The animal would
be considered to have cleared the safety radius as described above
under power down procedures.
(6) Ramp-Ups
A ramp-up of an airgun array provides a gradual increase in sound
levels, and involves a step-wise increase in the number and total
volume of air guns firing until the full volume is achieved. The
purpose of a ramp-up (or ``soft start'') is to ``warn'' cetaceans and
pinnipeds in the vicinity of the airguns and to provide the time for
them to leave the area and thus avoid any potential injury or
impairment of their hearing abilities.
During the proposed seismic survey, the seismic operator will ramp
up the airgun array slowly. NMFS requires the rate of ramp-up to be no
more than 6 dB per 5-minute period. Ramp-up is used at the start of
airgun operations, after a power- or shut-down, and after any period of
greater than 10 minutes in duration without airgun operations (i.e.,
extended shutdown).
A full ramp-up after a shut down will not begin until there has
been a minimum of 30 minutes of observation of the safety zone by PSOs
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 (e.g. harbor porpoises, harbor seals,
and Steller sea lions), or 30 minutes for large odontocetes (e.g.,
killer whales and beluga whales).
(7) Shut-Downs for Aggregations of Whales and Beluga Cow-Calf Pairs
The following additional protective measures beluga whale cow-calf
pairs and aggregations of whales are proposed. Specifically, a 160-dB
vessel monitoring zone would be established and monitored in Cook Inlet
during all seismic surveys. Whenever an aggregation of beluga whales or
killer whales (five or more whales of any age/sex class that appear to
be engaged in a non-migratory, significant biological behavior (e.g.,
feeding, socializing)), or beluga whale cow-calf pairs are observed
approaching the 160-dB safety zone around the survey operations, the
survey activity would not commence or would shut down, until they are
no longer present within the 160-dB safety zone of seismic surveying
operations.
Additional Mitigation Measures Proposed by NMFS
Furthermore, NMFS proposes the following measures be included in
the IHA, if issued:
(1) All vessels should reduce speed when within 300 yards (274 m)
of whales, and those vessels capable of steering around such groups
should do so. Vessels may not be operated in such a way as to separate
members of a group of whales from other members of the group;
(2) Avoid multiple changes in direction and speed when within 300
yards (274 m) of whales; and
(3) When weather conditions require, such as when visibility drops,
support vessels must adjust speed (increase or decrease) and direction
accordingly to avoid the likelihood of injury to whales.
Mitigation Measures Considered But Not Proposed
NMFS considered whether time/area restrictions were warranted. NMFS
has preliminary determined that such restrictions are not necessary or
practicable here. Beluga whales remain in Cook Inlet year-round, but
demonstrate seasonal movement within the Inlet; in the summer and fall,
they concentrate in upper Cook Inlet's rivers and bays, but tend to
disperse offshore and move to mid-Inlet in winter (Hobbs et al., 2005).
The available information indicates that in the winter months belugas
are dispersed in deeper waters in mid-Inlet past Kalgin Island, with
occasional forays into the upper inlet, including the upper ends of
Knik and Turnagain Arms. Their winter
[[Page 73444]]
distribution does not appear to be associated with river mouths, as it
is during the warmer months. The spatial dispersal and diversity of
winter prey are likely to influence the wider beluga winter range
throughout the mid-Inlet. Apache now expects to mobilize crews and
equipment for its seismic survey in January 2013, which would coincide
with the time of year when belugas are dispersed offshore in the mid-
Inlet and away from river mouths. In the spring, beluga whales are
regularly sighted in the upper Inlet beginning in late April or early
May, coinciding with eulachon runs in the Susitna River and Twenty Mile
River in Turnagain Arm, and well outside of the area where Apache will
be conducting seismic surveys. Therefore, NMFS believes that the timing
and location of the seismic survey, as proposed, will avoid areas and
seasons that overlap with important beluga whale behavioral patterns.
NMFS also considered whether to require time area restrictions for
areas identified as home ranges during August through March for 14
satellite-tracked beluga whales in Hobbs et al., 2005. NMFS has
preliminarily determined not to require time/area restrictions for
these areas within the phase 2 survey area. The areas in question
within phase 2 are relatively large areas in which belugas are
dispersed. In addition, data for 14 tracked belugas does not establish
that belugas will not appear in other areas--particularly during the
periods of the year when belugas are more dispersed in Cook Inlet.
Time/area restrictions for these areas thus would not yield a material
benefit for the species. Such restrictions also are not practicable
given the applicant's need to survey the areas in question and the need
for operational flexibility given weather conditions, real-time
adjustment of operations to avoid marine mammals and other factors.
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, 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 Apache's IHA Application
The monitoring plan proposed by Apache can be found in section 13
of the IHA application. The plan may be modified or supplemented based
on comments or new information received from the public during the
public comment period. A summary of the primary components of the plan
follows.
(1) Visual Vessel-Based Monitoring
Vessel-based monitoring for marine mammals would be done by
experienced PSOs throughout the period of marine survey activities.
PSOs would 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.
PSO duties would 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 PSOs would be required onboard the survey
vessel to meet the following criteria: (1) 100 percent monitoring
coverage during all periods of survey operations in daylight; (2)
maximum of 4 consecutive hours on watch per PSO; and (3) maximum of 12
hours of watch time per day per PSO.
PSO teams would consist of experienced field biologists. An
experienced field crew leader would supervise the PSO team onboard the
survey vessel. Apache currently plans to have PSOs aboard the three
vessels: the two source vessels (M/V Peregrine Falcon and M/V Arctic
Wolf) and one support vessel (M/V Dreamcatcher). Two PSOs would be on
the source vessels and two PSOs would be on the support vessel to
observe the safety, power down, and shut down areas. When marine
mammals are about to enter or are sighted within designated safety
zones, airgun or pinger operations would be powered down (when
applicable) or shut down immediately. The vessel-based observers would
watch for marine mammals during all periods when sound sources are in
operation and for a minimum of 30 minutes prior to the start of airgun
or pinger operations after an extended shut down.
Crew leaders and most other biologists serving as observers would
be individuals with experience as observers during seismic surveys in
Alaska or other areas in recent years.
The observer(s) would watch for marine mammals from the best
available vantage point on the source and support vessels, typically
the flying bridge. The observer(s) would scan systematically with the
unaided eye and 7x50 reticle binoculars. Laser range finders would be
available to assist with estimating distance. Personnel on the bridge
would assist the observer(s) in watching for marine mammals.
All observations would be recorded in a standardized format. Data
would be entered into a custom database using a notebook computer. The
accuracy of the data would be verified by computerized validity data
checks as the data are entered and by subsequent manual checks of the
database. These procedures would allow for initial summaries of the
data to be prepared during and shortly after the completion of the
field program, and would facilitate transfer of the data to
statistical, geographical, or other programs for future processing and
achieving. When a mammal sighting is made, the following information
about the sighting would 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 PSO, apparent reaction to
activities (e.g., none, avoidance, approach, paralleling, etc.),
[[Page 73445]]
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 PSO
location.
The ship's position, speed of support vessels, and water
temperature, water depth, sea state, ice cover, visibility, and sun
glare would 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.
(2) Visual Shore-Based Monitoring
In addition to the vessel-based PSOs, Apache proposes to utilize a
shore-based station to visually monitor for marine mammals. The shore-
based station would follow all safety procedures, including bear
safety. The location of the shore-based station would need to be
sufficiently high to observe marine mammals; the PSOs would be equipped
with pedestal mounted ``big eye'' (20x110) binoculars. The shore-based
PSOs would scan the area prior to, during, and after the air gun
operations, and would be in contact with the vessel-based PSOs via
radio to communicate sightings of marine mammals approaching or within
the project area.
(3) Aerial-Based Monitoring
When survey operations occur near a river mouth, Apache will
utilize the crew helicopter to conduct aerial surveys near river mouths
prior to the commencement of airgun operations in order to identify
locations where beluga whales congregate. The helicopter may also be
used at other times. The helicopter would not be used every day, but
will be used when survey operations occur near a river mouth. The types
of helicopters currently planned for use by Apache include a Bell 407,
Bell UH1B, and ASB3. Weather and scheduling permitting, aerial surveys
would fly at an altitude of 305 m (1,000 ft). In the event of a marine
mammal sighting, aircraft would attempt to maintain a radial distance
of 457 m (1,500 ft) from the marine mammal(s). Aircraft would avoid
approaching marine mammals from head-on, flying over or passing the
shadow of the aircraft over the marine mammal(s). By following these
operational requirements, sound levels underwater are not expected to
meet or exceed NMFS harassment thresholds (Richardson et al., 1995;
Blackwell et al., 2002).
(4) Acoustic Monitoring
To further enhance detection of cetaceans, Apache proposes to
deploy passive acoustic monitoring (PAM) devices during the seismic
survey. Apache anticipates utilizing the same system that was deployed
under the April 2012 IHA, which involved an over-the-side hydrophone
floating from the M/V Dreamcatcher. Apache would continue to use this
system until a better mooring system for the PAM buoys is developed.
The PAM operators would use specialized real-time detection software
and audio playback to detect marine mammal sounds. If the PAM operators
detect marine mammals, Apache would initiate a temporary shut-down of
the airgun arrays to avoid takes. Following a shut-down, the airguns
may be restarted in accordance with the ramp-up procedure described
earlier.
Based on data collected from Apache during its survey operations
conducted under the April 2012 IHA, NMFS believes that the foregoing
monitoring measures will allow Apache to identify animals nearing or
entering the 160 db zone with a reasonably high degree of accuracy.
Reporting Measures
(1) Field Reports
During the proposed survey program, the PSOs would prepare a report
each day or at such other interval as the IHA (if issued), or Apache
may require, summarizing the recent results of the monitoring program.
The field reports would summarize the species and numbers of marine
mammals sighted. These reports would be provided to NMFS and to the
survey operators on a weekly basis. At the end of each month, a summary
of the weekly reports would be submitted to NMFS.
(2) Technical Report
The results of Apache's 2013 monitoring program, including
estimates of ``take'' by harassment (based on presence in the 160 dB
harassment zone), would be presented in the ``90-day'' and Final
Technical reports. The Technical Report would 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 seismic survey activities (and other variables that could
affect detectability), such as:
Initial sighting distances versus survey activity state;
Closest point of approach versus survey activity state;
Observed behaviors and types of movements versus survey
activity state;
Numbers of sightings/individuals seen versus survey
activity state;
Distribution around the source vessels versus survey
activity state; and
Estimates of take by harassment based on presence in the
160 dB disturbance zone.
(3) Comprehensive Report
Following the survey season, a comprehensive report describing the
vessel-based, shore-based, aerial-based, and acoustic monitoring
programs would be prepared. The comprehensive report would describe the
methods, results, conclusions and limitations of each of the individual
data sets in detail. The report would also integrate (to the extent
possible) the studies into a broad based assessment of industry
activities, and other activities that occur in Cook Inlet, and their
impacts on marine mammals. The report would help to establish long-term
data sets that can assist with the evaluation of changes in the Cook
Inlet ecosystem. The report would attempt to provide a regional
synthesis of available data on industry activity in this part of Alaska
that may influence marine mammal density, distribution and behavior.
(4) Notification of Injured or Dead Marine Mammals
In the unanticipated event that the specified activity clearly
causes the take of a marine mammal in a manner prohibited by the IHA
(if issued), such as an injury (Level A harassment), serious injury or
mortality (e.g., ship-strike, gear interaction, and/or entanglement),
Apache would immediately cease the specified activities and immediately
report the incident to the Chief of the Permits and Conservation
Division, Office of Protected Resources, NMFS, and the Alaska Regional
Stranding Coordinators. The report would include the following
information:
[[Page 73446]]
Time, date, and location (latitude/longitude) of the
incident;
Name and type of vessel involved;
Vessel's speed during and leading up to the incident;
Description of the incident;
Status of all sound source use in the 24 hours preceding
the incident;
Water depth;
Environmental conditions (e.g., wind speed and direction,
Beaufort sea state, cloud cover, and visibility);
Description of all marine mammal observations in the 24
hours preceding the incident;
Species identification or description of the animal(s)
involved;
Fate of the animal(s); and
Photographs or video footage of the animal(s) (if
equipment is available).
Activities would not resume until NMFS is able to review the
circumstances of the prohibited take. NMFS would work with Apache to
determine what is necessary to minimize the likelihood of further
prohibited take and ensure MMPA compliance. Apache would not be able to
resume their activities until notified by NMFS via letter, email, or
telephone.
In the event that Apache discovers an injured or dead marine
mammal, and the lead PSO determines that the cause of the injury or
death is unknown and the death is relatively recent (i.e., in less than
a moderate state of decomposition as described in the next paragraph),
Apache would immediately report the incident to the Chief of the
Permits and Conservation Division, Office of Protected Resources, NMFS,
and the NMFS Alaska Stranding Hotline and/or by email to the Alaska
Regional Stranding Coordinators. The report would include the same
information identified in the paragraph above. Activities would be able
to continue while NMFS reviews the circumstances of the incident. NMFS
would work with Apache to determine whether modifications in the
activities are appropriate.
In the event that Apache discovers an injured or dead marine
mammal, and the lead PSO determines that the injury or death is not
associated with or related to the activities authorized in the IHA
(e.g., previously wounded animal, carcass with moderate to advanced
decomposition, or scavenger damage), Apache would report the incident
to the Chief of the Permits and Conservation Division, Office of
Protected Resources, NMFS, and the NMFS Alaska Stranding Hotline and/or
by email to the Alaska Regional Stranding Coordinators, within 24 hours
of the discovery. Apache would provide photographs or video footage (if
available) or other documentation of the stranded animal sighting to
NMFS and the Marine Mammal Stranding Network.
Estimated Take of Marine Mammals
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 marine survey
program. Anticipated impacts to marine mammals are associated with
noise propagation from the sound sources (e.g., airguns and pingers)
used in the seismic survey; no take is expected to result from the
detonation of explosives onshore, as supported by the SSV study, or
from vessel strikes.
Apache requests authorization to take five marine mammal species by
Level B harassment. These five marine mammal species are: Cook Inlet
beluga whale (Delphinapterus leucas); killer whale (Orcinus orca);
harbor porpoise (Phocoena phocoena); harbor seal (Phoca vitulina
richardsi), and Steller sea lion (Eumetopias jubatus).
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 seismic survey 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). The
most common and likely impact would be from behavioral disturbance,
including avoidance of the ensonified area or changes in speed,
direction, and/or diving profile of the animal. Hearing impairment (TTS
and PTS) are highly unlikely to occur based on the proposed mitigation
and monitoring measures that would preclude marine mammals being
exposed to noise levels high enough to cause hearing impairment.
For impulse sounds, such as those produced by airgun(s) used in the
seismic survey, NMFS uses the 160 dBrms re 1 [mu]Pa isopleth
to indicate the onset of Level B harassment. To estimate take by Level
B harassment, Apache provided calculations for the 160-dB isopleths and
then overlaid those isopleths with the density of marine mammals in the
total area ensonified within those isopleths over the time of the
surveys. Apache 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. NMFS used Apache's
takes estimates in its analyses.
Basis for Estimating ``Take by Harassment''
As stated previously, it is current NMFS policy to estimate take by
Level B harassment for impulse sounds at a received level of 160
dBrms re 1[mu]Pa. As described earlier in this notice,
impulsive sounds would be generated by airgun arrays that would be used
to obtain geological data during the surveys. To estimate potential
takes by Level B harassment in this application, as well as for
mitigation radii to be implemented by PSOs, ranges to the 160
dBrms re 1 [micro]Pa isopleths were estimated at three
different water depths (5 m, 25 m, and 45 m) for nearshore surveys and
at 80 m for channel surveys. The distances to this threshold for the
nearshore survey locations are provided in Table 1 and correspond to
the three transects modeled at each site in the onshore, nearshore, and
parallel to shore directions. The distances to the thresholds for the
channel survey locations are provided in Table 2 and correspond to the
broadside and endfire directions. The areas ensonified to the 160 dB
isopleth for the nearshore survey are provided in Table 3. The area
ensonifed to the 160 dB isopleth for the channel survey is 389 km\2\.
The following subsections describe the estimated densities of
marine mammals that may occur in the areas where activities are
planned, and areas of water that may be ensonified by pulsed sounds to
>=160 dB.
Marine mammal densities near the planned activities in Cook Inlet
were estimated from the annual aerial surveys conducted by NMFS between
2000 and 2011 for Cook Inlet beluga whales (Rugh et al. 2000, 2001,
2002, 2003, 2004, 2005, 2006, 2007; Shelden et al. 2008, 2009, 2010;
Hobbs et al. 2011). These surveys are flown in June to collect
abundance data for beluga whales, but sightings of other marine mammals
are also reported. Although these data are only collected in one month
each year, these surveys provide the best available relatively long-
term data set for sighting information in the proposed action area, but
do not correct for missed whales or account for seasonal variations in
[[Page 73447]]
distribution or habitat use of each species.
The maximum and average densities over the course of the total
survey years (2000-2011) are provided in Table 5. As discussed below,
beluga whales are observed in higher concentrations near river mouths,
particularly the Susitna River, due to feeding. In the IHA application
for Area 1, Apache attempted to account for the higher concentrations
near river mouths by using the highest number of beluga whales observed
for each survey to provide a density for near river mouths. Conversely,
to account for the lower concentrations away from river mouths, the
average number of beluga whales observed for each survey was used to
provide a density away from river mouths. However, based on comments
received regarding this methodology, for the Area 2 IHA application,
Apache has included only the highest daily total observed in the survey
(not total over the entire survey period because of re-sighting). These
densities were used to estimate the number of Level B takes incidental
to the proposed activity.
Table 5--Summary of Marine Mammal Densities
------------------------------------------------------------------------
Density (number/km\2\)
------------------------------------------------------------------------
Species Maximum Average
------------------------------------------------------------------------
Beluga whale (maximum number observed-- 0.00128 0.00051
rivers)................................
Harbor seal (total number observed)..... 0.00644 0.00317
Harbor porpoise (total number observed). 0.00179 0.00006
Killer whale (total number observed).... 0.00011 0.00001
Steller sea lion (total number observed) 0.00035 0.00011
------------------------------------------------------------------------
Fifteen species of marine mammals are known to occur in Cook Inlet,
but only five (Cook Inlet beluga whales, killer whales, harbor
porpoises, harbor seals, and Steller sea lions) are likely to be
encountered during the proposed survey activities. Two of the five
species (Cook Inlet beluga whales and western population of Steller sea
lions) are listed as endangered under the ESA.
Potential Number of Takes by Harassment
This subsection provides estimates of the number of individuals
potentially exposed to sound levels >= 160 dBrms re 1 [mu]Pa
during seismic survey operations. The estimates were calculated by
multiplying the expected densities by the anticipated area ensonified
by levels >= 160 dBrms re 1 [mu]Pa by the number of expected
days that will be subject to seismic survey activities in the action
area. According to section 2 in Apache's IHA application, a survey crew
will collect seismic data 10-12 hours per day over approximately 160
days over the course of 8 to 9 months. Apache assumes that over the
course of these 160 days, 100 days would be working in the offshore
region and 60 days would be working in the shallow, intermediate, and
deep nearshore region. Of those 60 days in the nearshore region, 20
days would be spent working in each of the three depths. It is
important to note that environmental conditions (such as ice, wind, and
fog) will play a significant role in the actual number of operating
days; therefore, these estimates are conservative in order to provide a
basis for the probability of encountering these marine mammal species
in the action area.
The number of estimated takes by Level B harassment was calculated
using the following assumptions:
The number of nearshore and shallow water survey days is
20 and daily acoustic footprint is 356 km\2\.
The number of nearshore and intermediate water depth
survey days is 20 and daily acoustic footprint is 468 km\2\.
The number of nearshore and deep water depth survey days
is 20 days and daily acoustic footprint is 455 km\2\.
The number of offshore survey days is 100 and daily
acoustic footprint is 389 km\2\.
Table 6 shows the probability of sightings per species for the
second year of seismic surveys in Area 2 with the methods and
assumptions outlined above. As noted earlier, the use of the NMML
aerial survey data has inherent weaknesses. For example, the densities
used here were calculated based on a relatively large area that was
surveyed compared to Area 2, sightings of beluga whales are not
corrected from missed animals, and the results do not account for
changes in the seasonal distribution of all species.
In addition, the probability of sightings for harbor seals and
Steller sea lions is higher than what is anticipated because there are
no haul-out sites within the action area. These density estimates are
skewed by the numbers observed in large haul outs during aerial
surveys. Seals in the water usually travel in small groups or as single
individuals; therefore, although Table 6 indicates an average of 204
and maximum of 414 seals to be observed, it is highly unlikely that
those number of seals will actually be taken by harassment during the
proposed seismic survey.
Similarly, and for many of the same reasons, the number of actual
takes by Level B harassment of Steller sea lions is expected to be much
lower than the average of four and maximum of 22. During the NMFS
aerial surveys, no Steller sea lions were observed in upper Cook Inlet.
Less than five Steller sea lions have been observed by the Port of
Anchorage monitoring program, and those observed have been juvenile
animals (likely male). To date, only one Steller sea lions has been
observed during seismic survey operations conducted under the April
2012 IHA. Therefore, Apache anticipates that there will be less than
five Steller sea lions in the proposed action area during the one-year
effective period of the IHA, if issued.
The average and maximum observations for harbor porpoise and killer
whales shown in Table 6 appear to be reasonable based on the NMFS
aerial surveys, although the actual number of animals is expected to be
low.
The average and maximum estimated sightings of Cook Inlet beluga
whales in Area 2 are 32 and 82, respectively. However, it is important
to note that a combination of factors--including extensive visual and
acoustic monitoring used throughout this project, particularly for
sighting beluga whales approaching the area--are expected to result in
the actual number of takes being much lower than these estimates. In
addition, the total number of days surveying that will actually occur
near river mouths is much lower than the 160 days used to estimate
takes in the different water depths; therefore, this take estimate is
likely to be extremely conservative. As a result, due to the
[[Page 73448]]
actual number of days and hours Apache is likely to be operating air
guns near river mouths and taking into account the monitoring and
mitigation measures applicable when operating seismic survey equipment
near rivers, Apache expects the actual number of takes by Level B
harassment estimated for Cook Inlet beluga whales to be much lower than
the numbers provided in Table 6.
Table 6--Probability of Sightings per Species for Year 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Shallow (356 km\2\) Intermediate (458 Deep (455 km\2\) Offshore (389 Total
---------------------- km\2\) ---------------------- km\2\) ---------------------
20 days ---------------------- 20 days ---------------------- 60 days
Species ---------------------- 20 days ---------------------- 100 days ---------------------
---------------------- ----------------------
max avg max avg max avg max avg max avg
--------------------------------------------------------------------------------------------------------------------------------------------------------
Beluga whales............................. 9.1 3.6 11.7 4.6 11.6 4.6 49.7 19.7 82.1 32.6
Harbor seals.............................. 45.9 22.6 59.0 29.0 58.6 28.9 250.5 123.4 414 203.8
Harbor porpoises.......................... 12.8 0.4 16.4 0.6 16.3 0.6 69.7 2.4 115.2 4.0
Killer whales............................. 0.8 0.1 1.0 0.1 1.0 0.1 4.3 0.6 7.2 1.0
Steller sea lions......................... 2.5 0.8 3.2 1.1 3.2 1.0 13.6 4.5 22.5 7.4
--------------------------------------------------------------------------------------------------------------------------------------------------------
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 requested take numbers of
individual cetaceans exposed to sounds 160 dBrms
re 1 [mu]Pa represent varying proportions of the populations of each
species in Cook Inlet (Table 7). For Cook Inlet beluga whales, Apache
requests 30 takes by Level B harassment. The number of beluga whale
takes requested is based, in part, on the average number of sightings
estimated over the course of the survey (see Table 6), as well as the
seasonal distribution and habitat use of belugas in Cook Inlet and the
monitoring information acquired during the seismic survey conducted
under the 2012 IHA. This number is approximately 10 percent of the
population of approximately 284 animals (Hobbs et al. 2011). For other
cetaceans that might occur in the vicinity of the seismic survey in
Cook Inlet, the requested takes represent an even smaller percentage of
their respective populations. The requested takes of 10 killer whales
and 20 harbor porpoises represent 0.89 percent and 0.06 percent of
their respective populations in the proposed action area.
Pinnipeds--Two pinniped species may be encountered in the proposed
action area, but the harbor seal is likely to be the more abundant
species in this area. The number of takes requested for individuals
exposed to sounds at received levels 160 dBrms re
1 [mu]Pa during the proposed seismic survey are as follows: harbor
seals (200) and Steller sea lions (20). These numbers represent 0.69
percent and 0.12 percent of their respective populations in the
proposed action area.
Table 7--Requested Number of Takes
------------------------------------------------------------------------
Number of
Species requested Population Percent of
takes abundance population
------------------------------------------------------------------------
Beluga whales................. 30 284 10.56
Harbor seals.................. 200 29,175 0.69
Harbor porpoises.............. 20 31,406 0.06
Killer whales................. 10 1,437 0.89
Steller sea lions............. 20 41,197 0.12
------------------------------------------------------------------------
Preliminary Determinations
Negligible Impact
NMFS has defined ``negligible impact'' in 50 CFR 216.103 as ``* * *
an impact resulting from the specified activity that cannot be
reasonably expected to, and is not reasonably likely to, adversely
affect the species or stock through effects on annual rates of
recruitment or survival.'' In making a negligible impact determination,
NMFS considers a variety of factors, including but not limited to: (1)
The number of anticipated mortalities; (2) the number and nature of
anticipated injuries; (3) the number, nature, intensity, and duration
of Level B harassment; and (4) the context in which the takes occur.
Given the required mitigation and related monitoring, no injuries
or mortalities are anticipated to occur as a result of Apache's
proposed seismic survey in Cook Inlet, 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. The small number of takes that are anticipated are expected to
be limited to short-term Level B behavioral harassment. Although it is
possible that some marine mammals individuals may be exposed to sounds
from seismic survey activities more than once, the duration of these
multi-exposures is expected to be low since both the animals and the
survey vessels will be moving constantly in and out of the survey area
and the seismic airguns do not operate continuously all day, but for a
few hours at a time totaling about 12 hours a day.
Odontocete (including Cook Inlet beluga whales, killer whales, and
harbor porpoises) reactions to seismic energy pulses are usually
assumed to be limited to shorter distances from the airgun(s) than are
those of mysticetes, in part because odontocete low-frequency hearing
is assumed to be less sensitive than that of mysticetes. 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). However, as
noted above, Cook Inlet belugas are more accustomed
[[Page 73449]]
to anthropogenic sound than beluga whales in the Beaufort Sea.
Accordingly, NMFS does not find this data determinative here. Also, due
to the dispersed distribution of beluga whales in Cook Inlet during
winter and the concentration of beluga whales in upper Cook Inlet from
late April through early fall, belugas would likely occur in small
numbers in the phase two survey area during the survey period and few
will likely be affected by the survey activity in a manner that would
be considered behavioral harassment. In addition, due to the constant
moving of the survey vessel, the duration of the noise exposure by
cetaceans to seismic impulse would be brief. For the same reason, it is
unlikely that any individual animal would be exposed to high received
levels multiple times.
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''. Animals are not expected to permanently abandon any area
that is surveyed, and any behaviors that are interrupted during the
activity are expected to resume once the activity ceases. Only a very
small portion of marine mammal habitat will be affected at any time,
and other areas within Cook Inlet will be available for necessary
biological functions. In addition, the area where the survey will take
place is not known to be an important location where beluga whales
congregate for feeding, calving, or nursing.
Furthermore, the estimated numbers of animals potentially exposed
to sound levels sufficient to cause Level B harassment are low
percentages of the population sizes in Cook Inlet, as shown in Table 7.
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 of the seismic survey are expected to be
short-term, with no lasting biological consequence. Therefore, the
exposure of cetaceans to sounds produced by the phase two seismic
survey is not anticipated to have an effect on annual rates or
recruitment or survival.
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 sound multiple times is much lower than if the source is stationary.
Taking into account the mitigation measures that are planned, effects
on pinnipeds 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''.
Animals are not expected to permanently abandon any area that is
surveyed, and any behaviors that are interrupted during the activity
are expected to resume once the activity ceases. Only a very small
portion of marine mammal habitat will be affected at any time, and
other areas within Cook Inlet will be available for necessary
biological functions. In addition, the area where the survey will take
place is not known to be an important location where pinnipeds haulout.
The closest known haulout site is located on Kalgin Island, which is
about 22 km from the McArther River. Therefore, NMFS has preliminarily
determined that the exposure of pinnipeds to sounds produced by the
proposed seismic survey in Cook Inlet 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.
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 size of Cook Inlet 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.
Small Numbers
The requested takes proposed to be authorized represent 10 percent
of the Cook Inlet beluga whale population of approximately 284 animals
(Hobbs et al., 2011), 0.89 percent of the combined Alaska resident
stock and Gulf of Alaska, Aleutian Island and Bering Sea stock of
killer whales (1,123 residents and 314 transients), and 0.06 percent of
the Gulf of Alaska stock of approximately 31,046 harbor porpoises. The
take requests presented for harbor seals represent 0.69 percent of the
Gulf of Alaska stock of approximately 29,175 animals. The requested
takes proposed for Steller sea lions represent 0.12 percent of the
western stock of approximately 41,197 animals. These take 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. The
number of marine mammals taken is small relative to the affected
species or stocks. 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.
Conclusion
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 the total taking from Apache's
proposed seismic survey in Cook Inlet will have a negligible impact on
the affected species or stocks. NMFS also preliminarily finds that
small numbers of marine mammals will be taken relative to the
populations of the affected species or stocks.
Impact on Availability of Affected Species or Stock for Taking for
Subsistence Uses
Section 101(a)(5)(D) also requires NMFS to determine that the
authorization will not have an unmitigable adverse effect on the
availability of marine mammal species or stocks for subsistence use.
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.
The subsistence harvest of marine mammals transcends the
nutritional and economic values attributed to the animal and is an
integral part of the cultural identity of the region's Alaska Native
communities. Inedible parts of the whale provide Native artisans with
materials for cultural handicrafts, and the hunting itself perpetuates
Native traditions by transmitting traditional
[[Page 73450]]
skills and knowledge to younger generations (NOAA 2007). However, due
to dramatic declines in the Cook Inlet beluga whale population, on May
21, 1999, legislation was passed to temporarily prohibit (until October
1, 2000) the taking of Cook Inlet belugas under the subsistence harvest
exemption in section 101(b) of the MMPA without a cooperative agreement
between NMFS and the affected Alaska Native Organizations (ANOs) (Pub.
L. 106-31, section 3022, 113 Stat. 57,100). That prohibition was
extended indefinitely on December 21, 2000 (Pub. L. 106-553, section
1(a)(2), 114 Stat. 2762). NMFS subsequently entered into six annual co-
management agreements (2000-2003, 2005-2006) with the Cook Inlet Marine
Mammal Council, an ANO representing Cook Inlet beluga hunters, which
allowed for the harvest of 1-2 belugas. On October 15, 2008, NMFS
published a final rule that established long-term harvest limits on the
Cook Inlet beluga whales that may be taken by Alaska Natives for
subsistence purposes (73 FR 60976). That rule prohibits harvest for a
5-year period (2008-2012), if the average abundance for the Cook Inlet
beluga whales from the prior five years (2003-2007) is below 350
whales. The next 5-year period that could allow for a harvest (2013-
2017), would require the previous five-year average (2008-2012) to be
above 350 whales.
There is a low level of subsistence hunting for harbor seals in
Cook Inlet. Seal hunting occurs opportunistically among Alaska Natives
who may be fishing or travelling in the upper Inlet near the mouths of
the Susitna River, Beluga River, and Little Susitna River. Consistent
with NMFS' implementing regulations, Apache met with the Cook Inlet
Marine Mammal Council (CIMMC)--a now dissolved ANO that represented
Cook Inlet tribes--on March 29, 2011, to discuss the proposed
activities and discuss any subsistence concerns. Apache also met with
the Tyonek Native Corporation on November 9, 2010 and the Salamatof
Native Corporation on November 22, 2010. Additional meetings were held
with the Native Village of Tyonek, the Kenaitze Indian Tribe, and Knik
Tribal Council, and the Ninilchik Traditional Council. According to
Apache, during these meetings, no concerns were raised regarding
potential conflict with subsistence harvest of marine mammals. Apache
has identified the following features that are intended to reduce
impacts to subsistence users:
In-water seismic activities will follow mitigation
procedures to minimize effects on the behavior of marine mammals and,
therefore, opportunities for harvest by Alaska Native communities; and
Regional subsistence representatives may support recording
marine mammal observations along with marine mammal biologists during
the monitoring programs and will be provided with annual reports.
Since the issuance of the April 2012 IHA, Apache has maintained
regular and consistent communication with federally recognized Alaska
Natives. The Alaska Natives, Native Corporations, and ANOs that Apache
has communicated with include: The Native Village of Tyonek; Tyonek
Native Corporation; Ninilchik Native Association; Ninilchik Traditional
Council; Salamatof Native Association; Knikatnu; Knik Native Council;
Alexander Creek; Cook Inlet Region, Inc.; the Native Village of
Eklutna; Kenaitze Indian Tribe; and Seldovia Native Association. Apache
has shared information gathered during the seismic survey conducted
under the April 2012 IHA, and plans on hosting an information exchange
with Alaska Native Villages, Native Corporations, and other Non-
Governmental Organizations in the spring of 2013 where data from the
past year's monitoring operations would be presented.
Apache concluded, and NMFS agrees, that the size of the affected
area, mitigation measures, and input from the consultations Alaska
Natives should result in the proposed action having no effect on the
availability of marine mammals for subsistence uses. Apache and NMFS
recognize the importance of ensuring that ANOs and federally recognized
tribes are informed, engaged, and involved during the permitting
process and will continue to work with the ANOs and tribes to discuss
operations and activities.
On February 6, 2012, in response to requests for government-to-
government consultations by the CIMMC and Native Village of Eklutna,
NMFS met with representatives of these two groups and a representative
from the Ninilchik. We engaged in a discussion about the proposed IHA
for Area 1, the MMPA process for issuing an IHA, concerns regarding
Cook Inlet beluga whales, and how to achieve greater coordination with
NMFS on issues that impact tribal concerns. Following the publication
of the proposed IHA, NMFS will be contacting the local Native Villages
to inform them of the availability of the Federal Register notice and
the opening of the public comment period.
NMFS anticipates that any effects from Apache's proposed seismic
survey on marine mammals, especially harbor seals and Cook Inlet beluga
whales, which are or have been taken for subsistence uses, would be
short-term, site specific, and limited to inconsequential changes in
behavior and mild stress responses. NMFS does not anticipate that the
authorized taking of affected species or stocks will reduce the
availability of the species to a level insufficient for a harvest to
meet subsistence needs by: (1) Causing the marine mammals to abandon or
avoid hunting areas; (2) directly displacing subsistence users; or (3)
placing physical barriers between the marine mammals and the
subsistence hunters; and that cannot be sufficiently mitigated by other
measures to increase the availability of marine mammals to allow
subsistence needs to be met. Therefore, NMFS has preliminarily
determined that the proposed regulations will not have an unmitigable
adverse impact on the availability of marine mammal stocks for
subsistence uses.
Endangered Species Act (ESA)
There are two marine mammal species listed as endangered under the
ESA with confirmed or possible occurrence in the proposed project area:
the Cook Inlet beluga whale and Steller sea lion. In addition, the
proposed action would occur within designated critical habitat for the
Cook Inlet beluga whales. On September 2, 2011, NMFS' Permits and
Conservation Division initiated consultation under section 7 of the ESA
with the Alaska Regions, NMFS, Protected Resources Division on the
issuance of IHAs to Apache under section 101(a)(5)(D) of the MMPA,
which includes the action area for this proposed activity. In February
2012, this consultation was concluded and a Biological Opinion was
issued. The Biological Opinion determined that the issuance of IHAs is
not likely to jeopardize the continued existence of the Cook Inlet
beluga whales or the western DPS of Steller sea lions, or destroy or
adversely modify Cook Inlet beluga whale critical habitat. Finally, the
BiOp included an Incidental Take Statement (ITS) for Cook Inlet beluga
whales and Steller sea lions. The ITS contains reasonable and prudent
measures implemented by terms and conditions to minimize the effects of
this take.
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
[[Page 73451]]
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 Apache's seismic
survey in Cook Inlet, Alaska, provided the previously mentioned
mitigation, monitoring, and reporting requirements are incorporated.
Dated: December 4, 2012.
Helen M. Golde,
Acting Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2012-29740 Filed 12-5-12; 4:15 pm]
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