[Federal Register: June 25, 2008 (Volume 73, Number 123)]
[Notices]
[Page 36044-36062]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr25jn08-60]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XD76
Taking Marine Mammals Incidental to Specified Activities; Seismic
Surveys in the Beaufort and Chukchi Seas
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice of receipt of application and proposed incidental take
authorization; request for comments.
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SUMMARY: NMFS has received an application from Shell Offshore, Inc.
(SOI) and its contractor WesternGeco for an Incidental Harassment
Authorization (IHA) to take small numbers of marine mammals, by
harassment, incidental to conducting marine geophysical programs,
including deep seismic surveys, on oil and gas lease blocks located on
Outer Continental Shelf (OCS) waters in the Beaufort and Chukchi Seas.
Under the Marine Mammal Protection Act (MMPA), NMFS is requesting
comments on its proposal to issue an IHA to SOI and WesternGeco to
incidentally take, by Level B harassment, small numbers of several
species of marine mammals during the Arctic Ocean open-water seasons
between August 1, 2008 and July 31, 2009, incidental to conducting
these seismic surveys.
DATES: Comments and information must be received no later than July 25,
2008.
ADDRESSES: Written comments on the application should be addressed to
Mr. P. Michael Payne, Chief, Permits, Conservation and Education
Division, Office of Protected Resources, National Marine Fisheries
Service, 1315 East-West Highway, Silver Spring, MD 20910-3225, or by
telephoning the contact listed here. The mailbox address for providing
email comments is PR1.XD76@noaa.gov. Comments sent via e-mail,
including all attachments, must not exceed a 10-megabyte file size.
A copy of the application (containing a list of the references used
in this document) may be obtained by writing to this address or by
telephoning the contact listed here and are also available at: http://
www.nmfs.noaa.gov/pr/permits/incidental.htm#iha.
A copy of the Minerals Management Service (MMS) Final Programmatic
Environmental Assessment (Final PEA) and the NMFS/MMS Draft
Programmatic Environmental Impact Statement (Draft PEIS) are available
at: http://www.mms.gov/alaska/.
Documents cited in this document that are not available through
standard public library access methods, may be viewed, by appointment,
during regular business hours at this address.
FOR FURTHER INFORMATION CONTACT: Kenneth Hollingshead, Office of
Protected Resources, NMFS, (301) 713-2289, or Brad Smith, NMFS, Alaska
Regional Office 907-271-3023.
SUPPLEMENTARY INFORMATION:
Background
Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.)
direct the Secretary of Commerce to allow, upon request, the
incidental, but not intentional, taking of marine mammals by U.S.
citizens who engage in a specified activity (other than commercial
fishing) within a specified geographical region if certain findings are
made and either regulations are issued or, if the taking is limited to
harassment, a notice of a proposed authorization is provided to the
public for review.
An authorization shall be granted if NMFS finds that the taking
will have a negligible impact on the species or stock(s) and will not
have an unmitigable adverse impact on the availability of the species
or stock(s) for subsistence uses and the permissible methods of taking
and requirements pertaining to the mitigation, monitoring and reporting
of such takings are set forth. NMFS has defined ``negligible impact''
in 50 CFR 216.103 as ''...an impact resulting from the specified
activity that cannot be reasonably expected to, and is not reasonably
likely to, adversely affect the species or stock through effects on
annual rates of recruitment or survival.''
Section 101(a)(5)(D) of the MMPA established an expedited process
by which citizens of the United States can apply for an authorization
to incidentally take small numbers of marine mammals by harassment.
Except with respect to certain activities not pertinent here, the MMPA
defines ``harassment'' as:
any act of pursuit, torment, or annoyance which (i) has the
potential to injure a marine mammal or marine mammal stock in the
wild [Level A harassment]; or (ii) has the potential to disturb a
marine mammal or marine mammal stock in the wild by causing
disruption of behavioral patterns, including, but not limited to,
migration, breathing, nursing, breeding, feeding, or sheltering
[Level B harassment].
Section 101(a)(5)(D) establishes a 45-day time limit for NMFS
review of an application followed by a 30-day public notice and comment
period on any proposed authorizations for the incidental harassment of
marine mammals. Within 45 days of the close of the comment period, NMFS
must either issue or deny the authorization.
Summary of Request
On October 16, 2007, NMFS received an application from SOI for the
taking, by harassment, of several species of marine mammals incidental
to conducting a marine seismic survey program during the open water
season between August 1, 2008 and July 31, 2009 (referred to in this
document as 2008/2009). SOI is planning a variety of programs in the
Chukchi and Beaufort Seas during the 2008/2009 open water seasons,
including a: (1) Chukchi Sea deep 3-D seismic survey; (2) Beaufort Sea
deep 3-D seismic survey; and (3) Beaufort Sea marine surveys, which
includes three activities: (a) site clearance and shallow hazards
surveys; (b) an ice-gouge survey; and (c) a strudel scour survey.
The deep seismic survey components of the program will be conducted
from WesternGeco's vessel, M/V Gilavar. Detailed specifications on this
seismic survey vessel are provided in Attachment A of SOI's IHA
application. These specifications include: (1) complete descriptions of
the number and lengths of the streamers which form the hydrophone
arrays; (2) airgun size and sound propagation properties; and (3)
additional detailed data on the M/V Gilavar's characteristics. In
summary, the M/V Gilavar will tow two source arrays, comprising three
identical subarrays each, which will be fired alternately as the ship
progresses downline in the survey area. The M/V Gilavar will tow up to
6 streamer cables up to 5.4 kilometers (km)(3.4 mi) long. With this
configuration each pass of the M/V Gilavar can record 12 subsurface
lines spanning a swath of up to 360 meters (1181 ft). The seismic
acquisition vessel will be supported by the M/V Gulf Provider, or a
similar vessel. The M/V Gulf Provider will serve as a crew change,
resupply, fueling support of acoustic and marine mammal monitoring, and
seismic chase vessel. It will not deploy seismic acquisition gear.
As SOI's 2007 IHA for open water seismic activities in the Chukchi
and Beaufort Seas is valid until August 1, 2008, this IHA request is
intended, therefore, for the open water seasons between August 2, 2008
through July 31, 2009.
As marine mammals may be affected by seismic and vessel noise, SOI
has requested an authorization under section 101(a)(5)(D) of the MMPA
to
[[Page 36045]]
take marine mammals by Level B harassment while conducting seismic
surveys and related activities.
Plan for Seismic Operations
In its application, SOI notes that it plans for the M/V Gilavar to
be in the Chukchi Sea to begin seismic acquisition data on or after
July 20, 2008, move to the Beaufort Sea in mid-July through late
October, and conclude work in the Chukchi Sea around November 15, 2008.
For purposes of the MMPA, the Chukchi and Beaufort seas meet the
definition of a ``specific geographic region'' as defined under the
Act. As proposed, the 2008 seismic survey effort will last a maximum of
100 days of active data acquisition (excluding downtime due to weather
and other unforeseen delays). When ice conditions permit or when SOI
determines to do so (at present, SOI plans to work in the Chukchi Sea
until around September 25), the seismic and associated vessels will
transit to the Beaufort Sea to conduct seismic operation for part of
the this 100-day period. The proposed commencement date of July 20th
for starting seismic in the Chukchi Sea is designed to ensure that
there will be no conflict with the spring bowhead whale migration and
subsistence hunts conducted by Barrow, Pt. Hope, or Wainwright or the
beluga subsistence hunt conducted by the village of Pt. Lay in early
July. The approximate area of SOI's seismic survey operations are shown
in Figure 1 in SOI's IHA application.
3-D Deep Seismic Surveys
Chukchi Sea 3-D Deep Seismic Surveys
SOI and its geophysical (seismic) contractor, WesternGeco, propose
to conduct a marine geophysical (deep 3-D seismic) survey program
during open water season on various MMS Outer Continental Shelf (OCS)
lease blocks in the northern Chukchi Sea (see Figure 1 in SOI's IHA
application). The Chukchi Sea 3-D Deep Seismic survey will be conducted
on leases obtained under Lease Sale (LS) 193. The exact locations where
operations will occur within that sale area were not known at the time
of SOI's IHA application, but NMFS presumes they will take place on
lease blocks obtained as a result of the sale. However, in general SOI
notes that the seismic data acquisition will occur at least 25 mi (40
km) offshore of the coast and in waters with depths averaging about 40
m (131 ft).
The deep 3-D seismic survey is proposed to be conducted from
WesternGeco's vessel M/V Gilavar, described previously. Two ``chase
boats'' will accompany the seismic vessel. These two chase boats will
provide the following functions: (1) re-supply, (2) marine mammal
monitoring, (3) ice scouting, and (4) general support for the M/V
Gilavar. The chase boat vessels proposed for use in 2008 are the M/V
Theresa Marie and the M/V Torsvik. These vessels will not deploy any
seismic gear. In addition, a crew change vessel, the M/V Gulf Provider
or similar vessel and a landing craft, such as the M/V Maxime or
similar vessel, will support the M/V Gilavar, and the two chase boats
in the Chukchi Sea. The crew change vessel will be used to move
personnel and supplies from the seismic vessel, and two chase boats to
the nearshore areas. In turn, the landing craft will move personnel and
supplies from the crew change vessel, when it is located in nearshore
areas, to the beach (most likely this will be at Barrow). Lastly, the
Marine Mammal Monitoring and Mitigation Program (4MP) will have a
separate vessel for the proposed 2008 Program. The landing craft also
will be used to move personnel and equipment from the 4MP vessel to the
near shore areas.
Beaufort Sea Deep 3-D Seismic Surveys
The same seismic vessel (M/V Gilavar), seismic equipment, and chase
boats that are described for the Chukchi Sea Deep 3-D Seismic survey,
will be used to conduct deep 3-D seismic surveys in the central and
eastern Beaufort Sea (see Figure 2 in SOI's IHA application). The focus
of this activity will be on SOI's existing leases, but some activity in
the Beaufort Sea may occur outside of SOI's existing leases. The
landing craft, which will be used to move personnel and supplies from
vessels in the near shore to docking sites will most likely use West
Dock, or Oliktok Dock. Smaller vessels such as the Alaska Clean Seas
(ACS) bay boats, or similar vessels, may be used to assist in the
movement of people and supplies and support of the 4MP in the Beaufort
Sea. The specific geographic region for SOI's deep seismic program in
the Beaufort Sea will be in OCS waters including SOI leases beginning
east of the Colville River delta to west of the village of Kaktovik
(see Figure 2 in SOI's application). According to SOI's IHA
application, the Beaufort Sea program is planned to occur for a maximum
of 60 days (excluding downtime due to weather and unforeseen delays)
during open-water from mid-August to the end of October; however,
recent communications with SOI indicates that the Beaufort Sea seismic
program will not start until after September 25, 2008. This timing of
activities in the fall will avoid any significant conflict with the
Beaufort Sea bowhead whale subsistence hunt conducted by the Beaufort
Sea villages, because it is anticipated that the fall bowhead whale
hunt will have ended by that time.
Description of Marine 3-D Seismic Data Acquisition
In the seismic method, reflected sound energy produces graphic
images of seafloor and sub-seafloor features. The seismic system
consists of sources and detectors, the positions of which must be
accurately measured at all times. The sound signal comes from arrays of
towed energy sources. These energy sources store compressed air which
is released on command from the towing vessel. The released air forms a
bubble which expands and contracts in a predictable fashion, emitting
sound waves as it does so. Individual sources are configured into
arrays. These arrays have an output signal, which is more desirable
than that of a single bubble, and also serve to focus the sound output
primarily in the downward direction, which is useful for the seismic
method. This array effect also minimizes the sound emitted in the
horizontal direction.
The downward propagating sound travels to the seafloor and into the
geologic strata below the seafloor. Changes in the acoustic properties
between the various rock layers result in a portion of the sound being
reflected back toward the surface at each layer. This reflected energy
is received by detectors called hydrophones, which are housed within
submerged streamer cables which are towed behind the seismic vessel.
Data from these hydrophones are recorded to produce seismic records or
profiles. Seismic profiles often resemble geologic cross- sections
along the course traveled by the survey vessel.
Description of WesternGeco's Air-Gun Array
SOI is proposing to use WesternGeco's 3147-in\3\ Bolt-Gun Array for
its 3-D seismic survey operations in the Chukchi and Beaufort Seas.
WesternGeco's source arrays are composed of 3 identically tuned Bolt-
gun sub-arrays operating at an air pressure of 2,000 psi. In general,
the signature produced by an array composed of multiple sub-arrays has
the same shape as that produced by a single sub-array while the overall
acoustic output of the array is determined by the number of sub-arrays
employed.
The airgun arrangement for each of the three 1049-in\3\ sub-array
is detailed in SOI's application. As indicated in the
[[Page 36046]]
application's diagram, each sub-array is composed of six tuning
elements; two 2-airgun clusters and four single airguns. The standard
configuration of a source array for 3-D surveys consists of one or more
1049-in\3\ sub-arrays. When more than one sub-array is used, as here,
the strings are lined up parallel to each other with either 8 m or 10 m
(26 or 33 ft) cross-line separation between them. This separation was
chosen so as to minimize the areal dimensions of the array in order to
approximate point source radiation characteristics for frequencies in
the nominal seismic processing band. For the 3147-in\3\ array the
overall dimensions of the array are 15 m (49 ft) long by 16-m (52.5-ft)
wide.
Characteristics of Airgun Pulses
A discussion of the characteristics of airgun pulses was provided
in several previous Federal Register documents (see 69 FR 31792 (June
7, 2004) or 69 FR 34996 (June 23, 2004)) and is not repeated here.
Additional information can be found in the NMFS/MMS Draft PEIS (see
ADDRESSES). Reviewers are encouraged to read these earlier documents
for additional background information.
Marine Surveys
SOI proposes to conduct marine surveys (shallow hazards and other
activities) in the Beaufort and Chukchi seas in 2008. Acoustic systems
similar to the ones proposed for use by SOI during its planned marine
surveys have been described by NMFS previously (see 66 FR 40996 (August
6, 2001), 70 FR 13466 (March 21, 2005)). NMFS encourages readers to
refer to these documents for additional information on these systems. A
summary of SOI's planned activities is described next.
Beaufort Sea Marine Surveys
SOI proposes to conduct three marine survey activities in 2008 in
the U.S. Beaufort Sea: (1) Site Clearance and Shallow Hazards (2) Ice
Gouge Surveys, and (3) Strudel Scour Surveys. Marine surveys for site
clearance and shallow hazards, ice gouge, or strudel scour in the
Beaufort Sea can be accomplished by the M/V Henry Christofferson. No
other vessels, such as chase boats, are necessary to accomplish the
proposed marine survey work. Any necessary crew changes or 4MP
coordinated activities under this activity will utilize the same crew
change, landing craft, or 4MP vessel mentioned under the Beaufort Sea
Deep 3-D Seismic survey.
Site Clearance and Shallow Hazards
Marine surveys will include site clearance and shallow hazards
surveys of potential exploratory drilling locations. These surveys
gather data on: (1) bathymetry, (2) seabed topography and other seabed
characteristics (e.g., boulder patches), (3) potential geohazards
(e.g., shallow faults and shallow gas zones), and (4) the presence of
any archeological features (e.g., shipwrecks).
The focus of this activity will be on SOI's existing leases in the
central and eastern Beaufort Sea, but some activity may occur outside
of SOI's existing leases. Actual locations of site clearance and
shallow hazard surveys have not been definitively set as of the date of
this publication, although they will occur within the area outlined in
Figure 2 of SOI's IHA application.
The vessel that SOI expects to use for the site clearance and
shallow hazards surveys is the M/V Henry Christofferson, which is a
diesel-powered tug as described in Attachment A to SOI's IHA
application. SOI proposes to use the following acoustic
instrumentation, (or similar equipment) during this work. This is the
same equipment as was used on the M/V Henry Christofferson during 2007:
(1) Dual frequency subbottom profiler Datasonics CAP6000 Chirp II
(2 to7 kiloHertz [kHz] or 8 to 23 kHz) or similar;
(2) Medium penetration subbottom profiler, Datasonics SPR-1200
Bubble Pulser (400 (hertz [Hz]) or similar;
(3) High resolution multi-channel 2D system, 20 cubic inches
(in\3\) (2 by 10) gun array (0 to 150 Hz) or similar;
(4) Multi-beam bathymetric sonar, Seabat 8101 (240 Hz); or similar;
and
(5) Side-scan sonar system, Datasonics SIS-1500 (190 to 210 kHz) or
similar.
Ice Gouge Survey
Ice gouge surveys are a type of marine survey to determine the
depth and distribution of ice gouges in the sea bed. Ice gouge is
created by ice keels which project from the bottom of moving ice that
gouge into seafloor sediment. Remnant ice gouge features are mapped to
aid in predicting the prospect of, orientation, depth, and frequency of
future ice gouge. These surveys will focus on the potential,
prospective pipeline corridor between the Sivulliq Prospect in Camden
Bay and the nearshore Point Thomson area. The Sivulliq area will be
surveyed to gather geotechnical and seafloor hazard information as well
as data on ice gouges.
SOI proposes that the acoustic instrumentation described previously
in this document (or something similar) will be used, namely multi-beam
bathymetric sonar, side scan sonar and subbottom profiling. Actual
locations of the ice gouge surveys have not been definitively set as of
the date of this publication, although these will occur within the area
outlined in Figure 2 of SOI's IHA application. There are also some
platform siting lines proposed, which would employ a high resolution
multi-channel 2D system, 20 cubic inches (in\3\) (2 by 10) airgun array
(0 to 150 Hz) or similar system.
Strudel Scour Survey
During the early melt on the North Slope, the rivers begin to flow
and discharge water over the coastal sea ice near the river deltas.
That water rushes down holes in the ice (``strudels'') and scours the
seafloor. These erosional areas are called ``strudel scours''.
Information on these features is required for prospective pipeline
planning. Two proposed activities are required to gather this
information.
First, an aerial survey will be conducted via helicopter
overflights during the melt to locate the strudels; and strudel scour
marine surveys to gather bathymetric data. The overflights investigate
possible sources of overflood water and will survey local streams that
discharge in the vicinity of Point Thomson including the Staines River,
which discharges to the east into Flaxman Lagoon and the Canning River,
which discharges to the east directly into the Beaufort Sea. These
helicopter overflights were scheduled to occur during late May/early
June 2008 and, weather permitting, should take no more than four days.
There are no planned landings during these overflights other than at
the Deadhorse or Kaktovik airports.
Second, areas that have strudel scour identified during the aerial
survey will be verified and surveyed with a marine vessel after the
breakup of nearshore ice. This proposed activity is not anticipated to
take more than 5 days to conduct. The operation is conducted in the
shallow water areas near the coast in the vicinity of Point Thomson.
The vessel has not been contracted; however, it is anticipated that it
will be the diesel-powered R/V Annika Marie. This vessel will use the
following equipment:
(1) Multi-beam bathymetric sonar, Seabat 8101 (240 Hz); or similar
sonar; and
(2) Side-scan sonar system, Datasonics SIS-1500 (190 to 210 kHz) or
similar sonar.
The multi-beam bathymetric sonar and the side-scan sonar systems
both operate at frequencies greater than 180
[[Page 36047]]
kHz, the highest frequency considered by knowledgeable marine mammal
biologists to be of possible influence to marine mammals. Because no
taking of marine mammals will occur from this equipment, no
measurements of those two sources are planned by SOI, and no exclusion
zones for seals or whales would be established during operation of
those two sources. The acoustic instrumentation used on the seismic
vessels are described in SOI's IHA application.
Chukchi Sea Marine Surveys
Marine surveys will include site clearance and shallow hazards
surveys of potential exploratory drilling locations as required by MMS
regulations. These surveys gather data on: (1) bathymetry, (2) seabed
topography and other seabed characteristics (e.g., boulder patches),
(3) potential geohazards (e.g., shallow faults and shallow gas zones),
and (4) the presence of any archeological features (e.g., shipwrecks).
Marine surveys for site clearance and shallow hazards can be
accomplished by one vessel with acoustic sources. No other vessels,
such as chase boats, are necessary to accomplish the proposed work. Any
necessary crew changes or 4MP coordinated activities under this
activity will utilize the same crew change, landing craft, or 4MP
vessel mentioned under the Chukchi Sea deep 3D seismic surveys.
The Chukchi Sea marine surveys will be conducted by SOI on leases
acquired in OCS LS 193. Site clearance surveys are confined to small
specific areas within OCS blocks. Actual locations of site clearance
and shallow hazard surveys have not been definitively set as of the
date of SOI's IHA application, although these will occur within the
general area outlined in Figure 1 in SOI's IHA application. Before the
commencement of operations, survey location information will be
supplied to NMFS, MMS, other agencies and affected members of the
public as it becomes available. SOI has not contracted for a vessel at
the time of publication of this document.
Additional Information
A detailed description of the work proposed by SOI for the open-
water seasons of 2008/2009 is contained in SOI's application which is
available for review (see ADDRESSES). Also, a description of SOI's data
acquisition program proposed for the 2008/2009 season, and
WesternGeco's air-gun array to be employed during 2008/2009 has been
provided in previous IHA notices on SOI's seismic program (see 71 FR
26055, May 3, 2006; 71 FR 50027, August 24, 2006).
Description of Habitat and Marine Mammals Affected by the Activity
A detailed description of the Beaufort and Chukchi sea ecosystems
and their associated marine mammal populations can be found in the
NMFS/MMS Draft PEIS and the MMS Final Programmatic Environmental
Assessment (Final PEA) on Seismic Surveys (see ADDRESSES for
availability) and also in several other documents (e.g., MMS, 2007
Final EIS for Chukchi Sea Planning Area: Oil and Gas Lease Sale 193 and
Seismic Surveying Activities in the Chukchi Sea. MMS 2007-026).
Marine Mammals
The Beaufort/Chukchi Seas support a diverse assemblage of marine
mammals, including bowhead whales, gray whales, beluga whales, killer
whales, harbor porpoise, ringed seals, spotted seals, bearded seals,
walrus and polar bears. These latter two species are under the
jurisdiction of the U.S. Fish and Wildlife Service (USFWS) and are not
discussed further in this document. Descriptions of the biology and
distribution of the marine mammal species under NMFS' jurisdiction can
be found in SOI's IHA application, the 2007 NMFS/MMS Draft PEIS on
Arctic Seismic Surveys, and the MMS 2006 Final PEA on Arctic Seismic
Surveys. Information on these marine mammal species can also be found
in NMFS Stock Assessment Reports (SARS). The 2007 Alaska SARS document
is available at: http://www.nmfs.noaa.gov/pr/pdfs/sars/ak2007.pdf.
Please refer to those documents for information on these species.
Potential Effects of Seismic Surveys on Marine Mammals
Disturbance by seismic noise is the principal means of taking by
this activity. Support vessels and aircraft may provide a potential
secondary source of noise. The physical presence of vessels and
aircraft could also lead to non-acoustic effects on marine mammals
involving visual or other cues.
As outlined in previous NMFS documents, the effects of noise on
marine mammals are highly variable, and can, in general, be categorized
as follows (based on Richardson et al., 1995):
(1) The noise may be too weak to be heard at the location of the
animal (i.e., lower than the prevailing ambient noise level, the
hearing threshold of the animal at relevant frequencies, or both);
(2) The noise may be audible but not strong enough to elicit any
overt behavioral response;
(3) The noise may elicit reactions of variable conspicuousness and
variable relevance to the well being of the marine mammal; these can
range from temporary alert responses to active avoidance reactions such
as vacating an area at least until the noise event ceases;
(4) Upon repeated exposure, a marine mammal may exhibit diminishing
responsiveness (habituation), or disturbance effects may persist; the
latter is most likely with sounds that are highly variable in
characteristics, infrequent and unpredictable in occurrence, and
associated with situations that a marine mammal perceives as a threat;
(5) Any anthropogenic noise that is strong enough to be heard has
the potential to reduce (mask) the ability of a marine mammal to hear
natural sounds at similar frequencies, including calls from
conspecifics, and underwater environmental sounds such as surf noise;
(6) If mammals remain in an area because it is important for
feeding, breeding or some other biologically important purpose even
though there is chronic exposure to noise, it is possible that there
could be noise-induced physiological stress; this might in turn have
negative effects on the well-being or reproduction of the animals
involved; and
(7) Very strong sounds have the potential to cause temporary or
permanent reduction in hearing sensitivity. In terrestrial mammals, and
presumably marine mammals, received sound levels must far exceed the
animal's hearing threshold for there to be any temporary threshold
shift (TTS) in its hearing ability. For transient sounds, the sound
level necessary to cause TTS is inversely related to the duration of
the sound. Received sound levels must be even higher for there to be
risk of permanent hearing impairment. In addition, intense acoustic or
explosive events may cause trauma to tissues associated with organs
vital for hearing, sound production, respiration and other functions.
This trauma may include minor to severe hemorrhage.
Effects of Seismic Survey Sounds on Marine Mammals
Behavioral Effects
In its IHA application, SOI states that the only anticipated
impacts to marine mammals associated with noise propagation from vessel
movement and seismic airgun operations would be the
[[Page 36048]]
temporary and short term displacement of whales and seals from within
ensonified zones produced by such noise sources. Any impacts on the
whale and seal populations of the Beaufort and Chukchi Seas activity
areas are likely to be short-term and transitory arising from the
temporary displacement of individuals or small groups from locations
they may occupy at the times they are exposed to seismic sounds between
the 160- to 190-dB received levels. In the case of bowhead whales
however, that displacement might well take the form of a deflection of
the swim paths of migrating bowheads away from (seaward of) received
noise levels lower than 160 db (Richardson et al., 1999). Moreover, it
is not presently known at what distance after passing the seismic
source that bowheads will return to their previous migration route.
However, NMFS does not believe that this offshore deflection is
biologically significant (although it might be significant for purposes
of subsistence hunting, as discussed later) as the bowhead migration is
believed to remain within the general bowhead whale migratory corridor
in the U.S. Beaufort Sea, which varies annually based on environmental
factors.
SOI cites Richardson and Thomson [eds]. (2002) to support its
contention that there is no conclusive evidence that exposure to sounds
exceeding 160 dB have displaced bowheads from feeding activity. NMFS
notes that, in 2006, observations conducted onboard a seismic vessel
operating in the Canadian Beaufort Sea found that feeding bowhead
whales were not observed to respond to seismic sounds at levels of 160
dB or lower.
Results from the 1996-1998 BP and Western Geophysical seismic
monitoring programs in the Beaufort Sea indicate that most fall
migrating bowheads deflected seaward to avoid an area within about 20
km (12.4 mi) of an active nearshore seismic operation, with the
exception of a few closer sightings when there was an island or very
shallow water between the seismic operations and the whales (Miller et
al., 1998, 1999). The available data do not provide an unequivocal
estimate of the distance (and received sound levels) at which
approaching bowheads begin to deflect, but this may be on the order of
35 km (21.7 mi).
When the received levels of noise exceed some threshold, cetaceans
will show behavioral disturbance reactions. The levels, frequencies,
and types of noise that will elicit a response vary between and within
species, individuals, locations, and seasons. Behavioral changes may be
subtle alterations in surface, respiration, and dive cycles. More
conspicuous responses include changes in activity or aerial displays,
movement away from the sound source, or complete avoidance of the area.
The reaction threshold and degree of response also are related to the
activity of the animal at the time of the disturbance. Whales engaged
in active behaviors, such as feeding, socializing, or mating, appear
less likely than resting animals to show overt behavioral reactions,
unless the disturbance is perceived as directly threatening.
Masking
Although NMFS believes that some limited masking of low-frequency
sounds (e.g., whale calls) is a possibility during seismic surveys, the
intermittent nature of seismic source pulses (1 second in duration
every 16 to 24 seconds (i.e., less than 7 percent duty cycle)) will
limit the extent of masking. Bowhead whales are known to continue
calling in the presence of seismic survey sounds, and their calls can
be heard between seismic pulses (Greene et al., 1999, Richardson et
al., 1986). Masking effects are expected to be absent in the case of
belugas, given that sounds important to them are predominantly at much
higher frequencies than are airgun sounds.
Injury and Mortality
NMFS and SOI believe that there is no evidence that bowheads or
other marine mammals exposed to seismic sounds in the Arctic have
incurred an injury to their auditory mechanisms. While it is not
positively known whether the hearing systems of marine mammals very
close to an airgun would be at risk of temporary or permanent hearing
impairment, Richardson et al. (1995) notes that TTS is a theoretical
possibility for animals within a few hundred meters of the source. More
recently, scientists have determined that the received level of a
single seismic pulse might need to be ~210 dB re 1 [mu]Pa rms (~221-226
dB pk-pk) in order to produce brief, mild TTS. Exposure to several
seismic pulses at received levels near 200-205 dB (rms) might result in
slight TTS in a small odontocete, assuming the TTS threshold is a
function of the total received pulse energy. Seismic pulses with
received levels of 200-205 dB or more are usually restricted to a
radius of no more than 200 m (656 ft) around a seismic vessel operating
a large array of airguns. For baleen whales, there are no data, direct
or indirect, on levels or properties of sound that are required to
induce TTS. However, according to SOI, there is a strong likelihood
that baleen whales (i.e., bowheads, gray whales and humpback whales)
would avoid the approaching airguns (or vessel) before being exposed to
levels high enough for there to be any possibility of onset of TTS.
For pinnipeds, information indicates that for single seismic
impulses, sounds would need to be higher than 190 dB rms for TTS to
occur while exposure to several seismic pulses indicates that some
pinnipeds may incur TTS at somewhat lower received levels than do small
odontocetes exposed for similar durations. This indicates to NMFS that
the 190-dB safety zone (see Mitigation and Monitoring later in this
document) provides a sufficient buffer to prevent permanent threshold
shift (PTS) in pinnipeds.
A marine mammal within a radius of <=100 m (<=328 ft) around a
typical large array of operating airguns may be exposed to a few
seismic pulses at received levels of [gteqt]205 dB, and possibly more
pulses if the marine mammal moved with the seismic vessel. When PTS
occurs, there is physical damage to the sound receptors in the ear. In
some 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. However, as scientists are reluctant to cause injury
to a marine mammals, 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. Given the possibility that mammals close to an
airgun array might incur TTS, there has been further speculation about
the possibility that some individuals occurring very close to airguns
might incur PTS. Single or occasional occurrences of mild TTS are not
indicative of permanent auditory damage in terrestrial mammals.
Relationships between TTS and PTS thresholds have not been studied
in marine mammals, but are assumed to be similar to those in humans and
other terrestrial mammals. Acousticians are in general agreement that a
temporary shift in hearing threshold of up to 40 dB due to moderate
exposure times is fully recoverable and does not involve tissue damage
or cell loss. Liberman and Dodds (1987) state, ''... acute threshold
shifts as large as 60 dB are routinely seen in ears in which the
surface morphology of the stereocilia is perfectly normal.''
(Stereocilia are the sensory cells responsible for the sensation of
hearing.). In the chinchilla, no cases of TTS involve the loss of
stereocilia, but all cases of PTS do (Ahroon et al., 1996). Cell death
clearly qualifies as Level A harassment (injury)
[[Page 36049]]
under the MMPA. Because there is no cell death with modest (up to 40
dB) TTS, such losses of sensitivity constitute a temporary impairment
but not an injury, further supporting NMFS' precautionary approach that
establishment of seismic airgun shutdown at 180 dB for cetaceans and
190 dB for pinnipeds, will prevent auditory injury to marine mammals by
seismic airgun sounds.
NMFS notes that planned monitoring and mitigation measures
(described later in this document) have been designed to avoid sudden
onsets of seismic pulses at full power, to detect marine mammals
occurring near the array, and to avoid exposing them to sound pulses
that have any possibility of causing hearing impairment. Moreover, NMFS
does not expect that any marine mammals will be seriously injured or
killed during SOI's seismic survey activities, even if some animals are
not detected prior to entering the 180-dB and 190-dB isopleths (safety
zones) for cetaceans and pinnipeds, respectively. These criteria were
set to approximate a level below where Level A harassment (i.e.,
defined as ``any act of pursuit, torment or annoyance which has the
potential to injure a marine mammal or marine mammal stock in the
wild'') from acoustic sources was believed to begin. Because, a decade
or so ago, scientists did not have information on where PTS might occur
in marine mammals, the High Energy Seismic Survey (HESS) workshop
(HESS, 1997, 1999) set the level to prevent injury to marine mammals at
180 dB. NMFS concurred and determined that TTS, which is the mildest
form of hearing impairment that can occur during exposure to a strong
sound, may occur at these levels (180 dB for cetaceans, 190 dB for
pinnipeds). When a marine mammal experiences TTS, the hearing threshold
rises and a sound must be stronger in order to be heard. 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
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.
Strandings
In numerous past IHA notices for seismic surveys, commenters have
referenced two stranding events allegedly associated with seismic
activities, one off Baja California and a second off Brazil. NMFS has
addressed this concern several times and without new information, does
not believe that this issue warrants further discussion. For
information relevant to strandings of marine mammals, readers are
encouraged to review NMFS' response to comments on this matter found in
69 FR 74905 (December 14, 2004), 71 FR 43112 (July 31, 2006), 71 FR
50027 (August 24, 2006), and 71 FR 49418 (August 23, 2006). In
addition, a June, 2008 stranding of 30-40 melon-headed whales
(Peponocephala spp), off Madagascar that appears to be associated with
seismic surveys is currently under investigation. One report indicates
that the stranding began prior to seismic surveys starting.
It should be noted that marine mammal strandings recorded in the
Beaufort and Chukchi seas do not appear to be related to seismic
surveys. Finally, if bowhead and gray whales react to sounds at very
low levels by making minor course corrections to avoid seismic noise
and mitigation measures require SOI to ramp-up the seismic array to
avoid a startle effect, strandings are unlikely to occur in the Arctic
Ocean. As a result, NMFS does not expect any marine mammals will incur
serious injury, mortality or strandings in the Arctic Ocean.
Potential Impacts on Affected Species and Stocks of Marine Mammals
According to SOI, the only anticipated impacts to marine mammals
associated with SOI's seismic activities with respect to noise
propagation are from vessel movements and seismic air gun operations.
SOI states that these impacts would be temporary and short term
displacement of seals and whales from within ensonified zones produced
by such noise sources. Any impacts on the whale and seal populations of
the Beaufort and Chukchi Sea activity areas are likely to be short term
and transitory arising from the temporary displacement of individuals
or small groups from locations they may occupy at the times they are
exposed to seismic sounds at the 160-190 dB (or higher) received
levels. As noted elsewhere, it is highly unlikely that animals will be
exposed to sounds of such intensity and duration as to physically
damage their auditory mechanisms. In the case of bowhead whales that
displacement might well take the form of a deflection of the swim paths
of migrating bowheads away from (seaward of) received noise levels
greater than 160 db (Richardson et al., 1999). There is no evidence
that bowheads so exposed have incurred injury to their auditory
mechanisms. Also, there is no evidence that seals are more than
temporarily displaced from ensonified zones and no evidence that seals
have experienced physical damage to their auditory mechanisms even
within ensonified zones.
During the period of seismic acquisition in the Chukchi and
Beaufort seas, most marine mammals are expected to be dispersed
throughout the area. Bowhead whales are expected to be concentrated in
the Canadian Beaufort Sea during much of this time, where they are not
expected to be affected by SOI's seismic program. The peak of the
bowhead whale migration through the Beaufort and Chukchi seas typically
occurs in late August through October, and efforts to reduce potential
impacts during this time will be addressed with the actual start of the
migration and through discussions with the affected whaling
communities. In the Chukchi Sea, the timing of seismic activities will
take place while the whales are widely distributed and would be
expected to occur in very low numbers within the seismic activity area.
If SOI conducts seismic surveys in late September or October in the
Beaufort or Chukchi Sea, bowheads may travel in proximity to the
seismic survey activity areas and hear sounds from vessel traffic and
seismic activities, of which some might be displaced by the planned
activities.
The reduction of potential impacts during the fall bowhead whale
migratory period will be addressed through discussions with the whaling
communities. Starting in late August bowheads may travel in proximity
to SOI's planned Beaufort Sea seismic activity areas and may hear
sounds from vessel traffic and seismic activities, of which some might
be displaced seaward by the planned activities. However, at the present
time, SOI expects to significantly reduce its period of seismic
operations in the Beaufort Sea by remaining in the Chukchi Sea until
mid-September, entering the Beaufort Sea only after the fall
subsistence hunt has concluded and after a significant portion of the
bowhead whales would have left the Canadian Beaufort Sea on their
westward migration to the Chukchi Sea.
In addition, although there was apparently a period of concentrated
feeding in the central Beaufort Sea in September 2007, feeding does not
normally appear to be an important activity by bowheads migrating
through the eastern and central part of the Alaskan Beaufort Sea or the
Chukchi Sea in most years. Sightings of bowhead whales occur in the
summer near Barrow (Moore and DeMaster, 2000), and there are
suggestions that certain areas near Barrow are important feeding
[[Page 36050]]
grounds. In addition, a few bowheads can be found in the Chukchi and
Bering Seas during the summer and Rugh et al. (2003) suggests that this
may be an expansion of the western Arctic stock, although more research
is needed. In the absence of important feeding areas, the potential
diversion of a small number of bowheads away from seismic activities is
not expected to have any significant or long-term consequences for
individual bowheads or their population.
Effects on Individual Arctic Ocean Marine Mammal Species
In order to facilitate the reader's understanding of the knowledge
of impacts of impulsive noise on the principal marine mammal species
that are expected to be affected by SOI's proposed seismic survey
program, NMFS has previously provided a summary of potential impacts on
the bowhead, gray, and beluga whales and the ringed, largha and bearded
seals. This information can be found in the Federal Register (72 FR
31553, June 7, 2007). Information on impacts on marine mammals by
seismic activities can also be found in SOI's IHA application.
Numbers of Marine Mammals Expected to Be Harassed by Seismic Survey
Activities
The methodology used by SOI to estimate incidental take by
harassment by seismic and the numbers of marine mammals that might be
affected in the proposed seismic acquisition activity area in the
Chukchi and Beaufort seas has been presented in SOI's 2008 IHA
application.
In its application, SOI provides estimates of the number of
potential ``exposures'' to sound levels equal to or greater than 160 dB
re 1 [mu]Pa (rms). NMFS clarifies here that, except possibly for
bowhead whales, calculations of the number of exposures by SOI, does
not necessarily indicate that this is the number of Level B harassments
that SOI's seismic activity will take. First, exposure estimates do not
take into account variability between species or within a species by
activity, age or sex. What this means is that not all animals are
expected to react at the same level as its conspecifics, and all
species are not expected to react at the same level, as some species in
the Arctic will respond to sounds differently, if at all, depending
upon whether or not they have good hearing in the same frequency range
as seismic. Second, NMFS believes that SOI's use of the maximum density
estimates for its requested take authorization (see IHA application and
references for details) is overly cautious as it tends to inflate
harassment take estimates to an unreasonably high number and is not
based on good empirical science. NMFS believes that these inflated
numbers have been provided and used by SOI for its Level B harassment
take request in an abundance of caution because they present a worst-
case estimate. NMFS, on the other hand prefers to use the average
density estimate numbers provided in Tables 6-1 through 6-5 in SOI's
IHA application as these are the more realistic and scientifically
supportable estimates. NMFS notes, for example, that the most
comprehensive survey data set on ringed and bearded seals from the
central and eastern Beaufort Sea was conducted on offshore pack ice in
late spring. Density estimates of ringed and bearded seals were based
on counts of seals on the ice during this survey, not in open water
where seismic surveys are conducted. Consequently, the density and
potential take (exposure) numbers for seals in the Beaufort and Chukchi
seas will likely overestimate the number of seals that could be
encountered and/or exposed to seismic airguns because only animals in
the water near the survey area would be exposed to seismic and site
clearance activity sound sources. Because seals would be more widely
dispersed while in open water, NMFS presumes that animal densities
would be less than when seals are concentrated on and near the ice.
Compounding that error, SOI calculated the maximum density for seals as
4 times the average density, which NMFS does not believe is supported
by the best available science.
The estimates for marine mammal ``exposure'' are based on a
consideration of the number of marine mammals that might be appreciably
disturbed during approximately 7974 km (4955 mi) of full 3D seismic
surveys and approximately 4294 km (2668 mi) of mitigation gun activity
in the Chukchi Sea and by approximately 4784 km (2973 mi) of full 3D
seismic surveys and approximately 2576 km (1600 mi) of mitigation gun
(a single small airgun used when the airgun array is not active to
alert marine mammals to the presence of the survey vessel) activity in
the Beaufort Sea. In addition to the 3D seismic program, the shallow
hazards surveys using a 2 10 in\3\ airgun array will be performed along
approximately 1237 km (769 mi) in the Beaufort Sea and approximately
432 km (268 mi) in the Chukchi Sea.
NMFS further notes that the close spacing of neighboring tracklines
within the planned 3D seismic survey areas results in a limited amount
of total area of the Chukchi and Beaufort seas being exposed to sounds
[gteqt] 160 dB while much of the survey area is exposed repeatedly.
This means that the number of non-migratory cetaceans and pinnipeds
exposed to seismic sounds would be less than if the seismic vessel
conducted straight line transects of the sea without turning and
returning on a nearby, parallel track. However, these animals may be
exposed several times before the seismic vessel moves to a new site. In
that regard, NMFS notes that the methodology used by SOI in its
``exposure'' calculations is more valid for seismic surveys that
transect long distances, for those surveys that ``mow the lawn'' (that
is, remain within a relatively small area, transiting back and forth
while shooting seismic). In such situations, the Level B harassment
numbers tend to be highly inflated, if each ``exposure'' is calculated
to be a different animal and not, as here, a relatively small number of
animals residing in the area and being ``exposed'' to seismic sounds
several times during the season. As a result, NMFS believes that SOI's
estimated number of individual exposures does not account for multiple
exposures of the same animal (principally non-migratory pinnipeds)
instead of single animal exposures as the survey conducts a number of
parallel transects of the same area (sometimes called bostrophodontical
surveys) and the fact that the mitigation procedures would serve to
reduce exposures to affected marine mammals.
As mentioned previously, 3D seismic airgun arrays are composed of
identically tuned Bolt-gun sub-arrays operating at 2,000 psi. In
general, the signature produced by an array composed of multiple sub-
arrays has the same shape as that produced by a single sub-array while
the overall acoustic output of the array is determined by the number of
sub-arrays employed. The gun arrangement for the 1,049 square inches
(in2) sub-array is detailed below and is comprised of three subarrays
comprising a total 3,147 in2 sound source. The anticipated radii of
influence of the bathymetric sonars and pinger are less than those for
the air gun configurations described in Attachment A in SOI's IHA
application. It is assumed that, during simultaneous operations of
those additional sound sources and the air gun(s), any marine mammals
close enough to be affected by the sonars or pinger would already be
affected by the air gun(s). In this event, SOI believes that marine
mammals are not expected to exhibit more than short-term and
inconsequential responses, and such responses have not been
[[Page 36051]]
considered to constitute ``taking'' therefore, potential taking
estimates only include noise disturbance from the use of air guns. The
specifications of the equipment, including site clearance activities,
to be used and areas of ensonification are described more fully in
SOI's IHA application (see Attachment B in SOI's IHA application).
Cetaceans
For belugas and gray whales, in both the Beaufort and Chukchi Seas
and bowhead whales in the Chukchi Sea, Moore et al. (2000b and c) offer
the most current data to estimate densities during summer. Density
estimates for bowhead whales in the Beaufort Sea were updated by
information provided by Miller et al. (2002).
Tables 6-1 and 6-2 (Chukchi Sea) and Tables 6-3 and 6-4 (beluga and
bowhead: Beaufort Sea) provide density estimates for the summer and
fall, respectively. Table 6-5 provides a summary of the expected
densities for cetaceans (other than bowheads and belugas) and pinnipeds
during all seasons in the Beaufort Sea. The number of different
individuals of each species potentially exposed to received levels
[gteqt]160 dB re 1 [mu]Pa (rms) within each survey region, time period,
and habitat zone was estimated by multiplying the expected species
density, by the anticipated area to be ensonified to the 160-dB level
in the survey region, time period, and habitat zone to which that
density applies.
The numbers of ``exposures'' were then summed by SOI for each
species across the survey regions, seasons, and habitat zones. Some of
the animals estimated to be exposed, particularly migrating bowhead
whales, might show avoidance reactions before being exposed to
[gteqt]160 dB re 1 [mu]Pa (rms). Thus, these calculations actually
estimate the number of individuals potentially exposed to [gteqt]160 dB
that would occur if there were no avoidance of the area ensonified to
that level.
For the full-3D airgun array, the cross track distance is 2 the
160-dB radius which was measured in 2007 as 8.1 km (5.0 mi) in the
Chukchi Sea and 13.4 km (8.3 mi) in the Beaufort Sea. The mitigation
gun' 160-dB radius was measured at 1370 m (4495 ft) in the Chukchi Sea
and Beaufort seas. For shallow hazards surveys to be performed by the
Henry Christofferson, the 160-dB radius measured in 2007 was equal to
621 m (2037 ft). Using these distances, SOI estimates that the area
ensonified in the Chukchi Sea is approximately 15,000 km\2\ and
approximately 10,100 km\2\ in the Beaufort Sea.
The estimated numbers of potential marine mammal ``exposures'' by
SOI's surveys are presented in Tables 6-6 for the summer/fall period in
the Chukchi Sea, Table 6-7 for bowhead and beluga whales in the U.S.
Beaufort Sea and in Table 6-8 for marine mammals (other than bowheads
and belugas) in the Beaufort Sea. Table 1 in this document (Table 6-9
in the IHA application) summarizes these exposure estimates based on
the 160-dB re 1 [mu]Pa (rms) criteria for cetaceans exposed to impulse
sounds (such as seismic).
SOI's estimates show that the bowhead whale is the only endangered
marine mammal expected to be exposed to noise levels [gteqt] 160 dB
unless, as expected during the fall migratory period, bowheads avoid
the approaching survey vessel before the received levels reach 160 dB.
Migrating bowheads are likely to take avoidance measures, though many
of the bowheads engaged in other activities, particularly feeding and
socializing, probably will not. SOI's estimate of the number of bowhead
whales potentially exposed to [gteqt]160 dB is 1540 animals (9 in the
Chukchi Sea and 1531 in the Beaufort Sea (see Table 1)). Two other
endangered cetacean species that may be encountered in the northern
Chukchi/western Beaufort Sea area, the fin whale and humpback whale,
are estimated by SOI to have two exposures each in the Chukchi Sea.
However, NMFS believes that at least for the fin whale, no animals
would be so exposed given their low ``average'' estimates of densities
in the area.
Most of the cetaceans exposed to seismic sounds with received
levels [gteqt]160 dB would involve bowhead, gray, and beluga whales,
and the harbor porpoise. Average estimates of the number of exposures
of cetaceans by 3D seismic surveys (other than bowheads), in descending
order, are beluga (298), gray whale (183), and harbor porpoise (58).
The regional breakdown of these numbers is shown in Tables 6-6 to 6-8.
Estimates for other species are lower (Table 6-9). These estimates are
also provided in Table 1 in this Federal Register notice.
Pinnipeds
Ringed, spotted, and bearded seals are all associated with sea ice,
and most census methods used to determine density estimates for
pinnipeds are associated with counting the number of seals hauled out
on ice. Correction factors have been developed for most pinniped
species that address biases associated with detectability and
availability of a particular species. Although extensive surveys of
ringed and bearded seals have been conducted in the Beaufort Sea, the
majority of the surveys have been conducted over the landfast ice and
few seal surveys have been in open water. The most comprehensive survey
data set on ringed seals (and bearded seal) from the central and
eastern Beaufort Sea was conducted on offshore pack ice in late spring
(Kingsley, 1986). It is important to note that all proposed activities
will be conducted during the open-water season and density estimates
used here were based on counts of seals on ice. Therefore, densities
and potential take numbers will overestimate the numbers of seals that
would likely be encountered and/or exposed because only the animals in
the water would be exposed to the seismic and clearance activity sound
sources.
The ringed seal is the most widespread and abundant pinniped in
ice-covered arctic waters and ringed seals are expected to account for
the vast majority of marine mammals expected to be encountered, and
hence exposed to airgun sounds with received levels [gteqt]160 dB re 1
[mu]Pa (rms) during SOI's seismic survey. The average estimate is that
13,256 ringed seals might be exposed to seismic sounds with received
levels [gteqt]160 dB. Two additional pinniped species (other than the
Pacific walrus) are expected to be encountered. They are the bearded
seal (592 exposures), and the spotted seal (422 exposures)(see Table 1
in this document or Table 6-9 in the IHA application). The spotted seal
and ribbon seal are unlikely to be encountered during SOI's seismic
surveys.
[[Page 36052]]
TABLE 1. Summary of the Number of Potential Exposures of Marine Mammals to Received Sound Levels in the Water of [gteqt]160 dB During SOI's Proposed
Seismic Program in the Chukchi Sea and Beaufort Sea, Alaska, July - November, 2008. Not all marine mammals will change their behavior when exposed to
these sound levels, although some might alter their behavior somewhat when levels are lower (see text).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Number of Individuals Exposed to Sound Levels [gteqt]160dB
-----------------------------------------------------------------------------------------------------------------------
Species Chukchi Sea Beaufort Sea Total
-----------------------------------------------------------------------------------------------------------------------
Avg. Max. Avg. Max. Avg. Max.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Odontocetes
Monodontidae
Beluga 63 254 234 938 298 1192
Narwhal 0 0 0 0 0 0
Delphinidae
Killer whale 2 6 0 0 2 6
Phocoenidae
Harbor porpoise 57 227 2 6 58 234
Mysticetes
Bowhead Whale \a\ 9 46 1531 1536 1540 1582
Fin whale 2 6 0 0 2 6
Gray whale 182 727 2 6 183 734
Humpback whale 2 6 0 0 2 6
Minke whale 2 6 0 0 2 6
-----------------------------------------------------------------------------------------------------------------------
Total Cetaceans 70 281 1533 1543 1603 1824
Pinnipeds
Bearded seal 270 405 322 1286 592 1691
Ribbon seal 2 6 0 0 2 6
Ringed seal 6951 10827 6305 25221 13256 36047
Spotted seal 361 562 61 243 422 804
-----------------------------------------------------------------------------------------------------------------------
Total Pinnipeds 5678 8836 6687 26750 12366 35586
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ See text for description of bowhead whale estimate for the Beaufort Sea
Potential Marine Mammal Disturbance At Less Than 160 dB Received Levels
During autumn seismic surveys in the Beaufort Sea, migrating
bowhead whales displayed avoidance (i.e., deflection) at distances out
to 20-30 km (12-19 mi) and received sound levels of ~130 dB (rms)
(Miller et al., 1999; Richardson et al., 1999). Therefore, it is
possible that a larger number of bowhead whales than estimated above
may be disturbed to some extent if reactions occur at [gteqt]130 dB
(rms).
However, these references note that bowhead whales below the water
surface at a distance of 20 km (12.4 mi) from an airgun array received
pulses of about 117-135 dB re 1 [mu]Pa rms, depending upon propagation.
Corresponding levels at 30 km (18.6 mi) were about 107-126 dB re 1
[mu]Parms. Miller et al. (1999) surmise that deflection may have begun
about 35 km (21.7 mi) to the east of the seismic operations, but did
not provide SPL measurements to that distance, and noted that sound
propagation has not been studied as extensively eastward in the
alongshore direction, as it has northward, in the offshore direction.
Therefore, while this single year of data analysis indicates that
bowhead whales may make minor deflections in swimming direction at a
distance of 30-35 km (18.6-21.7 mi), there is no indication that the
sound pressure level (SPL) where deflection first begins is at 120 dB-
it could be at another SPL lower or higher than 120 dB. Miller et al.
(1999) also note that the received levels at 20-30 km (12.4-18.6 mi)
were considerably lower in 1998 than have previously been shown to
elicit avoidance in bowheads exposed to seismic pulses. However, the
seismic airgun array used in 1998 was larger than the ones used in 1996
and 1997. Therefore, NMFS believes that it cannot scientifically
support adopting any single SPL value below 160 dB and apply it across
the board for all species and in all circumstances.
Second, NMFS has noted in the past that minor course changes during
migration are not considered a significant behavioral change and, as
indicated in MMS' 2006 Final PEA, have not been seen at other times of
the year and during other activities. To show the contextual nature of
this minor behavioral modification, recent monitoring studies of
Canadian seismic operations indicate that when not migrating but
involved in feeding, bowhead whales do not move away from a noise
source at an SPL of 160 dB. Therefore, while bowheads may avoid an area
of 20 km (12.4 mi) around a noise source, when such a determination
requires a post-survey computer analysis to find that bowheads have
made slight course change, NMFS believes that this does not rise to a
level considered to be a significant behavioral response on the part of
the marine mammals or under the MMPA, a ``take.'' NMFS therefore
continues to estimate ``takings'' under the MMPA from impulse noises,
such as seismic, as being at a distance of 160 dB (re 1 [mu]Pa). NMFS
needs to point out however, that while this might not be a ``taking''
in the sense that there is not a significant behavioral response by
bowhead whales, a minor course deflection by bowheads can have a
significant impact on the subsistence uses of bowheads. As a result,
NMFS still requires mitigation measures to ensure that the activity
does not have an unmitigable adverse impact on subsistence uses of
bowheads.
Finally, it is likely that SOI will not conduct seismic operations
in the Beaufort Sea during that part of the fall bowhead migration that
occurs at the same time as the fall bowhead subsistence hunt. As a
result, a large proportion of the bowhead population would migrate past
the Beaufort Sea
[[Page 36053]]
seismic survey area without being exposed to any seismic sounds.
Limiting operations during the fall bowhead whale migration is also
meant to reduce any chance of conflicting with subsistence hunting and
will continue at least until hunting quotas have been filled by the
coastal communities.
Potential Impact on Habitat
SOI states that the proposed seismic activities will not result in
any permanent impact on habitats used by marine mammals, or to their
prey sources. Seismic activities will mostly occur during the time of
year when bowhead whales are widely distributed and would be expected
to occur in very low numbers within the seismic activity area (mid- to
late-July through September). Any effects would be temporary and of
short duration at any one place. The primary potential impacts to
marine mammals is associated with elevated sound levels from the
proposed airguns were discussed previously in this document.
A broad discussion on the various types of potential effects of
exposure to seismic on fish and invertebrates can be found in the NMFS/
MMS Draft PEIS for Arctic Seismic Surveys (see ADDRESSES).
Mortality to fish, fish eggs and larvae from seismic energy sources
would be expected within a few meters (0.5 to 3 m (1.6 to 9.8 ft)) from
the seismic source. Direct mortality has been observed in cod and
plaice within 48 hours that were subjected to seismic pulses two meters
from the source (Matishov, 1992), however other studies did not report
any fish kills from seismic source exposure (La Bella et al., 1996;
IMG, 2002; Hassel et al., 2003). To date, fish mortalities associated
with normal seismic operations are thought to be slight. Saetre and Ona
(1996) modeled a worst-case mathematical approach on the effects of
seismic energy on fish eggs and larvae, and concluded that mortality
rates caused by exposure to seismic are so low compared to natural
mortality that issues relating to stock recruitment should be regarded
as insignificant.
Limited studies on physiological effects on marine fish and
invertebrates to acoustic stress have been conducted. No significant
increases in physiological stress from seismic energy were detected for
various fish, squid, and cuttlefish (McCauley et al., 2000) or in male
snow crabs (Christian et al., 2003). Behavioral changes in fish
associated with seismic exposures are expected to be minor at best.
Because only a small portion of the available foraging habitat would be
subjected to seismic pulses at a given time, fish would be expected to
return to the area of disturbance anywhere from 15-30 minutes (McCauley
et al., 2000) to several days (Engas et al., 1996).
Available data indicates that mortality and behavioral changes do
occur within very close range to the seismic source, however, the
proposed seismic acquisition activities in the Chukchi and Beaufort
seas are predicted by SOI to have a negligible effect to the prey
resource of the various life stages of fish and invertebrates available
to marine mammals occurring during the project's duration. In addition,
it is unlikely that bowheads, gray, or beluga whales will be excluded
from any habitat.
Effects of Seismic Noise and Other Related Activities on Subsistence
The disturbance and potential displacement of marine mammals by
sounds from seismic activities are the principal concerns related to
subsistence use within the Beaufort and Chukchi seas. The harvest of
marine mammals (mainly bowhead whales, but also ringed and bearded
seals) is central to the culture and subsistence economies of the
coastal North Slope and Western Alaskan communities. In particular, if
fall-migrating bowhead whales are displaced farther offshore by
elevated noise levels, the harvest of these whales could be more
difficult and dangerous for hunters. The impact would be that whaling
crews would necessarily be forced to travel greater distances to
intercept westward migrating whales thereby creating a safety hazard
for whaling crews and/or limiting chances of successfully striking and
landing bowheads. The harvest could also be affected if bowheads become
more skittish when exposed to seismic noise. Hunters relate how bowhead
whales also appear ``angry'' due to seismic noise, making whaling more
dangerous.
This potential impact on subsistence uses of marine mammals is
proposed by SOI to be mitigated by application of the procedures
established in a Conflict Avoidance Agreement (CAA) between the seismic
operators and the AEWC and the Whaling Captains' Associations of
Kaktovik, Nuiqsut, Barrow, Pt. Hope and Wainwright. SOI notes that the
times and locations of seismic and other noise producing sources are
likely to be curtailed during times of active bowhead whale scouting
and actual whaling activities within the traditional subsistence
hunting areas of the potentially affected communities. (See Mitigation
for Subsistence). SOI states that seismic survey activities will also
be scheduled to avoid the traditional subsistence beluga hunt which
annually occurs in July in the community of Pt. Lay. As a result, SOI
believes that there should be no adverse impacts on the availability of
whale species for subsistence uses. In the event that a CAA is not
signed by either party, then NMFS will implement mitigation measures it
determines are necessary to ensure that the taking of marine mammals by
SOI's seismic and related activities do not have an unmitigable adverse
impact on the subsistence uses of marine mammals.
In the Chukchi Sea, SOI's seismic work should not have unmitigable
adverse impacts on the availability of the whale species for
subsistence uses. The whale species normally taken by Inupiat hunters
are the bowhead and belugas. SOI's Chukchi Sea seismic operations will
not begin until after July 20, 2008 by which time the majority of
bowheads will have migrated to their summer feeding areas in Canada.
Even if any bowheads remain in the northeastern Chukchi Sea after July
20, they are not normally hunted after this date until the return
migration occurs around late September when a fall hunt by Barrow
whalers takes place. In recent years, bowhead whales have occasionally
been taken in the fall by coastal villages along the Chukchi coast, but
the total number of these animals has been small. Seismic operations
for the Chukchi Sea seismic program will be timed and located so as to
avoid any possible conflict with the Barrow fall whaling, and specific
provisions governing the timing and location are expected to be
incorporated, if signed, into a CAA established between SOI and
WesternGeco, the AEWC, and the Whaling Captains Associations.
Beluga whales may also be taken sporadically for subsistence needs
by coastal villages, but traditionally are taken in small numbers very
near the coast. However, SOI will establish ``communication stations''
in the villages to monitor impacts. Gray whales, which will be abundant
in the northern Chukchi Sea from spring through autumn, are not taken
by subsistence hunters.
Plan of Cooperation (POC)
Regulations at 50 CFR 216.104(a)(12) require IHA applicants for
activities that take place in Arctic waters to provide a POC or
information that identifies what measures have been taken and/or will
be taken to minimize adverse effects on the availability of marine
mammals for subsistence purposes. SOI has summarized concerns received
during 2006 and 2007 into the 2007 POC, which was submitted during June
2007 to federal agencies as well as to
[[Page 36054]]
subsistence stakeholders, and updated in July 2007 and earlier this
year. SOI has developed the POC to mitigate and avoid any unreasonable
interference by SOI's planned activities on North Slope subsistence
uses and resources. The POC is the result of numerous meetings and
consultations between SOI, affected subsistence communities and
stakeholders, and federal agencies beginning in October 2006 (see Table
12-1 in SOI's IHA application for a list of meetings). The POC
identifies and documents potential conflicts and associated measures
that will be taken to minimize any adverse effects on the availability
of marine mammals for subsistence use. To be effective, SOI believes
the POC must be a dynamic document which will expand to incorporate the
communications and consultation that will continue to occur throughout
2008. Outcomes of POC meetings are included in quarterly updates
attached to the POC and distributed to federal, state, and local
agencies as well as local stakeholder groups.
SOI hopes that a CAA will result from the POC meetings. In that
regard, the AEWC submitted a draft CAA to the industry earlier this
spring. If signed, the CAA will incorporate all appropriate measures
and procedures regarding the timing and areas of the operator's planned
activities (e.g., times and places where seismic operations will be
curtailed or moved in order to avoid potential conflicts with active
subsistence whaling and sealing); a communications system between
operator's vessels and whaling and hunting crews (i.e., the
communications center will be located in strategic areas); provision
for marine mammal observers/Inupiat communicators aboard all project
vessels; conflict resolution procedures; and provisions for rendering
emergency assistance to subsistence hunting crews. If requested, post-
season meetings will also be held to assess the effectiveness of a 2008
CAA between SOI, the AEWC, and the Whaling Captains Associations, to
address how well conflicts (if any) were resolved; and to receive
recommendations on any changes (if any) might be needed in the
implementation of future CAAs.
It should be noted that NMFS is required by the MMPA to make a
determination that an activity would not have an unmitigable adverse
impact on the subsistence needs for marine mammals. While this includes
usage of both cetaceans and pinnipeds, the primary impact from seismic
activities is expected to be impacts from noise on bowhead whales
during its westward fall migration and feeding period in the Beaufort
Sea. NMFS has defined unmitigable adverse impact 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 (50 CFR 216.103).
Therefore, while a signed CAA allows NMFS to make a determination
that the activity will not have an unmitigable adverse impact on the
subsistence use of marine mammals, if one or both parties fail to sign
the CAA, then NMFS will make the determination that the activity will
or will not have an unmitigable adverse impact on subsistence use of
marine mammals. This determination may require that the IHA contain
additional mitigation measures in order for this decision to be made.
Mitigation and Monitoring
As part of its application, SOI has proposed implementing a marine
mammal mitigation and monitoring program (4MP) that will consist of
monitoring and mitigation during SOI's seismic and shallow-hazard
survey activities. In conjunction with monitoring during SOI's
exploratory drilling program (subject to a separate notice and review),
monitoring will provide information on the numbers of marine mammals
potentially affected by these activities and permit real time
mitigation to prevent injury of marine mammals by industrial sounds or
activities. These goals will be accomplished by conducting vessel-,
aerial-, and acoustic-monitoring programs to characterize the sounds
produced by the seismic airgun arrays and related equipment and to
document the potential reactions of marine mammals in the area to those
sounds and activities. Acoustic modeling will be used to predict the
sound levels produced by the seismic, shallow hazards and drilling
equipment in the U.S. Beaufort and Chukchi seas. For the seismic
program, acoustic measurements will also be made to establish zones of
influence (ZOIs) around the activities that will be monitored by
observers. Aerial monitoring and reconnaissance of marine mammals and
recordings of ambient sound levels, vocalizations of marine mammals,
and received levels should they be detectable using bottom-founded
acoustic recorders along the Beaufort Sea coast will be used to
interpret the reactions of marine mammals exposed to the activities.
The components of SOI's mitigation and monitoring programs are briefly
described next. Additional information can be found in SOI's
application.
Proposed Mitigation Measures
As part of its IHA application, SOI submitted its proposed
mitigation and monitoring program for SOI's seismic programs in the
Chukchi and Beaufort seas for 2008/2009. SOI notes that the proposed
seismic exploration program incorporates both design features and
operational procedures for minimizing potential impacts on cetaceans
and pinnipeds and on subsistence hunts. Seismic survey design features
include: (1) Timing and locating seismic activities to avoid
interference with the annual fall bowhead whale hunts; (2) configuring
the airgun arrays to maximize the proportion of energy that propagates
downward and minimizes horizontal propagation; (3) limiting the size of
the seismic energy source to only that required to meet the technical
objectives of the seismic survey; and (4) conducting pre-season
modeling and early season field assessments to establish and refine (as
necessary) the appropriate 180 dB and 190 dB safety zones, and other
radii relevant to behavioral disturbance.
The potential disturbance of cetaceans and pinnipeds during seismic
operations will be minimized further through the implementation of the
following several ship-based mitigation measures.
Safety and Disturbance Zones
Safety radii for marine mammals around airgun arrays are
customarily defined as the distances within which received pulse levels
are greater than or equal to 180 dB re 1 [mu]Pa (rms) for cetaceans and
greater than or equal to 190 dB re 1 [mu]Pa (rms) for pinnipeds. These
safety criteria are based on an assumption that seismic pulses at lower
received levels will not injure these animals or impair their hearing
abilities, but that higher received levels might result in such
effects. It should be understood that marine mammals inside these
safety zones will not necessarily be seriously injured or killed as
these zones were established prior to the current understanding that
significantly higher levels of impulse sounds would be required before
injury or mortality would occur. This has been described previously in
this document.
[[Page 36055]]
SOI anticipates that monitoring similar to that conducted in the
Chukchi Sea in 2007 will also be required in the Chukchi and the
Beaufort seas in 2008. SOI plans to use marine mammal observers (MMOs)
onboard the seismic vessel to monitor the 190- and 180-dB (rms) safety
radii for pinnipeds and cetaceans, respectively and to implement
appropriate mitigation as discussed in the proceeding sections. SOI
also plans to monitor the 160-dB (rms) disturbance zone with MMOs
onboard the chase vessels in 2008 as was done in 2006 and 2007. There
has also been concern that received pulse levels as low as 120 dB (rms)
may have the potential to disturb some whales. In 2006 and 2007, there
was a requirement in the IHAs issued to SOI by NMFS to implement
special mitigation measures if specified numbers of bowhead cow/calf
pairs might be exposed to seismic sounds greater than 120 dB rms or if
large groups (greater than 12 individuals) of bowhead or gray whales
might be exposed to sounds greater than or equal to 160 dB rms. In
2007, monitoring of the 120-dB (rms) zone was required in the Beaufort
Sea after 25 September. For 2008, SOI anticipates that it will not
operate in the Chukchi Sea between September 25th and the time ice
prevents additional work in the Beaufort Sea, by which time NMFS
believes the bowhead whale cow/calf migration period to have been
completed. As a result, it is unlikely that SOI will not need to
monitor the 120 dB (rms) zone in the Chukchi Sea in 2008.
During the 2006 and 2007 seismic programs in the Chukchi and
Beaufort Seas, SOI utilized a combination of pre-season modeling and
early season sound source verification to establish safety zones for
these sound level criteria. As the equipment being utilized in 2008 is
the same as that used in the 2006 and 2007 field seasons, and the
majority of locations where seismic data is to be acquired were modeled
prior to the 2006 and 2007 seasons, SOI will initially utilize the
derived (measured) sound criterion distances from 2006. Any locations
not modeled previously will be modeled prior to 2008 survey initiation
and mitigation distances and safety zones adjusted up, if necessary
following sound measurements at the new locations. Modeling of the
sound propagation is based on the size and configuration of the airgun
array and on available oceanographic data. An acoustics contractor will
perform the direct measurements of the received levels of underwater
sound versus distance and direction from the airgun arrays using
calibrated hydrophones. The acoustic data will be analyzed as quickly
as reasonably practicable in the field and used to verify (and if
necessary adjust) the safety distances. The mitigation measures to be
implemented will include ramp ups, power downs, and shut downs as
described next.
Ramp-Up
A ramp up of an airgun array provides a gradual increase in sound
levels, and involves a step-wise increase in the number and total
volume of airguns firing until the full volume is achieved. The purpose
of a ramp up (or ``soft start'') is to ``warn'' cetaceans and pinnipeds
in the vicinity of the airguns and to provide the time for them to
leave the area and thus avoid any potential injury or impairment of
their hearing abilities. During the proposed seismic program, the
seismic operator will ramp up the airgun arrays slowly, at a rate no
greater than 6 dB/5 minute period. Full ramp ups (i.e., from a cold
start after a shut down, when no airguns have been firing) will begin
by firing a small airgun in the arrays. The minimum duration of a shut-
down period, i.e., without air guns firing, which must be followed by a
ramp up typically is the amount of time it would take the source vessel
to cover the 180-dB safety radius. That depends on ship speed and the
size of the 180-dB safety radius, which are not known at this time.
A full ramp up, after a shut down, will not begin until there has
been a minimum of a 30-minute period of observation by MMOs of the
safety zone to assure that no marine mammals are present. The entire
safety zone must be visible during the 30-minute leading up to a full
ramp up. If the entire safety zone is not visible, then ramp up from a
cold start cannot begin. If a marine mammal(s) is sighted within the
safety zone during the 30-minute watch prior to ramp up, ramp up will
be delayed until the marine mammal(s) is sighted outside of the safety
zone or the animal(s) is not sighted for at least 15-30 minutes: 15
minutes for small odontocetes and pinnipeds, or 30 minutes for baleen
whales and large odontocetes.
During periods of turn around and transit between seismic
transects, at least one airgun will remain operational to alert marine
mammals in the area of the vessel's location. The ramp-up procedure
still will be followed when increasing the source levels from one air
gun to the full arrays. Moreover, keeping one air gun firing will avoid
the prohibition of a cold start during darkness or other periods of
poor visibility. Through use of this approach, seismic operations can
resume upon entry to a new transect without a full ramp up and the
associated 30-minute lead-in observations. MMOs will be on duty
whenever the airguns are firing during daylight, and during the 30-min
periods prior to ramp-ups as well as during ramp-ups. Daylight will
occur for 24 hr/day until mid-August, so until that date MMOs will
automatically be observing during the 30-minute period preceding a ramp
up. Later in the season, MMOs will be called out at night to observe
prior to and during any ramp up. The seismic operator and MMOs will
maintain records of the times when ramp-ups start, and when the airgun
arrays reach full power.
Power Downs and Shut Downs
A power down is the immediate reduction in the number of operating
airguns from all guns firing to some smaller number. A shut down is the
immediate cessation of firing of all airguns. The airgun arrays will be
immediately powered down whenever a marine mammal is sighted
approaching close to or within the applicable safety zone of the full
airgun arrays (i.e., 180 dB rms for cetaceans, 190 dB rms for
pinnipeds), but is outside the applicable safety zone of the single
airgun. If a marine mammal is sighted within the applicable safety zone
of the single airgun, the airgun array will be shut down (i.e., no
airguns firing). Although observers will be located on the bridge ahead
of the center of the airgun array, the shutdown criterion for animals
ahead of the vessel will be based on the distance from the bridge
(vantage point for MMOs) rather than from the airgun array - a
precautionary approach. For marine mammals sighted alongside or behind
the airgun array, the distance is measured from the array.
Operations at Night and in Poor Visibility
When operating under conditions of reduced visibility attributable
to darkness or to adverse weather conditions, infra-red or night-vision
binoculars will be available for use. However, it is recognized that
their effectiveness is limited. For that reason, MMOs will not
routinely be on watch at night, except in periods before and during
ramp-ups. It should be noted that if one small airgun remains firing,
the rest of the array can be ramped up during darkness or in periods of
low visibility. Seismic operations may continue under conditions of
darkness or reduced visibility.
[[Page 36056]]
Preliminary Mitigation Determination
As NMFS believes that the combination of use of the mitigation gun,
ramp-up of the seismic airgun array and the slow vessel speed (to allow
marine mammals sufficient time to take necessary avoidance measures),
the use of trained marine mammal observers and shut-down procedures (to
avoid potential injury if the animal is close to the vessel), and the
behavioral response of marine mammals (especially bowhead whales) to
avoid areas of high anthropogenic noise all provide protection to
marine mammals from serious injury or mortality. As a result, NMFS
believes that it is not necessary to require termination of survey
activities during darkness or reduced visibility and that the current
level of mitigation will result in the lowest level of impact on marine
mammals practicable.
Proposed Marine Mammal Monitoring
SOI has proposed to implement a marine mammal monitoring program
(4MP) to collect data to address the following specific objectives: (1)
improve the understanding of the distribution and abundance of marine
mammals in the Chukchi and Beaufort sea project areas; (2) understand
the propagation and attenuation of anthropogenic sounds in the waters
of the project areas; (3) determine the ambient sound levels in the
waters of the project areas; and (4) assess the effects of sound on
marine mammals inhabiting the project areas and their distribution
relative to the local people that depend on them for subsistence
hunting.
These objectives and the monitoring and mitigation goals will be
addressed by: (1) vessel-based MMOs on the seismic source and other
support vessels; (2) an acoustic program to predict and then measure
the sounds produced by the seismic operations and the possible
responses of marine mammals to those sounds; (3) an aerial monitoring
and reconnaissance of marine mammals available for subsistence harvest
along the Chukchi Sea coast; and (4) bottom-founded autonomous acoustic
recorder arrays along the Alaskan coast and offshore in the Chukchi and
Beaufort seas to record ambient sound levels, vocalizations of marine
mammals, and received levels of seismic operations should they be
detectable.
Seismic Source Vessel-based Visual Monitoring
A sufficient number of MMOs will be required to be onboard the
seismic source vessel to meet the following criteria: (1) 100 percent
monitoring coverage during all periods of seismic operations in
daylight and for the 30 minutes prior to starting ramp-up and for the
number of minutes required to reach full ramp-up; (2) coverage during
darkness for 30-minutes before and during ramp-ups (provided MMOs
verify that they can clearly see the entire safety zone); (3) maximum
of 4 consecutive hours on watch per MMO; (4) maximum of approximately
12 hours on watch per day per MMO with no other shipboard duties; and
(5) two-MMO coverage during ramp-up and the 30 minutes prior to full
ramp-ups and for as large a fraction of the other operating hours as
possible.
To accomplish these tasks SOI proposes to have from three to five
MMOs (including one Inupiat observer/communicator) based aboard the
seismic vessel. However, NMFS does not consider Inupiat observers to be
included in the required minimum number of MMOs unless they have
undergone MMO training at a facility approved in advance by NMFS. MMOs
will search for and observe marine mammals whenever seismic operations
are in progress and for at least 30 minutes before the planned start of
seismic transmissions or whenever the seismic array's operations have
been suspended for more than 10 minutes. The MMOs will scan the area
immediately around the vessels with reticle binoculars during the
daytime. Laser rangefinding equipment will be available to assist with
distance estimation. After mid-August, when the duration of darkness
increases, image intensifiers will be used by observers and additional
light sources may be used to illuminate the safety zone.
The seismic vessel-based work will provide the basis for real-time
mitigation (airgun power downs and, as necessary, shut downs), as
called for by the IHAs; information needed to estimate the ``take'' of
marine mammals by harassment, which must be reported to NMFS; data on
the occurrence, distribution, and activities of marine mammals in the
areas where the seismic program is conducted; information to compare
the distances, distributions, behavior; movements of marine mammals
relative to the source vessels at times with and without seismic
activity; a communication channel to Inupiat whalers through the
Communications Coordination Center in coastal villages; and continued
employment and capacity building for local residents, with one
objective being to develop a larger pool of experienced Inupiat MMOs.
The use of four or more MMOs allows two observers to be on duty
simultaneously for up to 50 percent of the active airgun hours. The use
of two observers increases the probability of detecting marine mammals,
and two observers will be on duty for the entire duration of time
whenever the seismic array is ramped up. As mentioned previously,
individual watches will be limited to no more than 4 consecutive hours
to avoid observer fatigue (and no more than 12 hours on watch per 24
hour day). When mammals are detected within or about to enter the
safety zone designated to prevent injury to the animals (see
Mitigation), the geophysical crew leader will be notified so that
shutdown procedures can be implemented immediately. Details of the
vessel-based marine mammal monitoring program are described in SOI's
IHA application (see Appendix B).
Chase Boat Monitoring
MMOs will also be present on smaller support vessels that travel
with the seismic source vessel. These support vessels are commonly
known as ``guard boats'' or ``chase boats.'' During seismic operations,
a chase boat remains very near to the stern of the source vessel
anytime that a member of the source vessel crew is on the back deck
deploying or retrieving equipment related to the seismic array. Once
the seismic array is deployed the chase boat then serves to keep other
vessels away from the seismic source vessel and the seismic array
itself (including hydrophone streamer) during production of seismic
data and provide additional emergency response capabilities.
In the Chukchi and Beaufort seas in 2008, SOI's seismic source
vessel will have one associated chase boat and possibly an additional
supply vessel. The chase boat and supply vessel (if present) will have
three MMOs onboard to collect marine mammal observations and to monitor
the 160 dB (rms) disturbance zone from the seismic airgun array. MMOs
on the chase boats will be able to contact the seismic ship if marine
mammals are sited. To maximize the amount of time during the day that
an observer is on duty, two observers aboard the chase boat or supply
vessel will rarely work at the same time. As on the source vessels,
shifts will be limited to 4 hrs in length and 12 hrs total in a 24 hr
period.
SOI plans to monitor the 160-dB (rms) disturbance radius in 2008
using MMOs onboard the chase vessel. The 160-dB radius in the Chukchi
Sea in 2007 was determined by JASCO (2007) to extend ~8.1 km from the
airgun
[[Page 36057]]
source on the M/V Gilavar. In the Beaufort Sea, the 160-dB radius was
measured at 13.45 km (8.4 mi) (JASCO, 2007). This area around the
seismic vessel was monitored by MMOs onboard the M/V Gulf Provider (the
chase boat used in 2006 and 2007 operations). As in 2007 during
monitoring of the 160-dB zone the M/V Gulf Provider will travel ~8 km
(5 mi) ahead and to the side of the M/V Gilavar. MMOs onboard the M/V
Gulf Provider will search the area ahead of the M/V Gilavar within the
160-dB zone for marine mammals. Every 8 km (5 mi) or so, the M/V Gulf
Provider will move to the other side of the M/V Gilivar continuing in a
stair-step type pattern. The distance at which the M/V Gulf Provider
(or other equivalent vessel) travels ahead of the M/V Gilavar will be
determined by the measured 160-dB radius. Mitigation (i.e., power down
or shut down of the airgun array) will be implemented if a group of 12
or more bowhead or gray whales enter the 160-dB zone. SOI will use this
same protocol in the Beaufort Sea after the 160-dB radius has been
determined. Depending upon the size of the measured 160-dB zone around
the airgun array SOI may decide to use a vessel equipped with a Passive
Acoustic Monitoring (PAM) system (if it has been independently field
tested and certified to NMFS as being capable of detecting marine
mammals that inhabit the Arctic Ocean) or may use a second chase boat
to ensure effective monitoring of the area.
In 2007 the measured distance to the 180-dB isopleth ranged from
about 2.45 km (1.5 mi) in the Chukchi Sea to about 2.2 km (1.4 mi) in
the Beaufort Sea near the Sivulliq prospect. SOI decided to use an
additional vessel to monitor this zone given its importance in
protecting marine mammals from potential injury associated with
exposure to seismic pulses. Depending upon the measured radius for the
180-dB zone in 2008/2009 SOI may elect to use a PAM system to help
monitor this area around the M/V Gilavar as well.
Aerial Survey Program
SOI proposes to conduct an aerial survey program in support of the
seismic exploration program in the Beaufort Sea during summer and fall
of 2008. The objectives of the aerial survey will be: (1) to advise
operating vessels as to the presence of marine mammals in the general
area of operation; (2) to provide mitigation monitoring (120 dB zones)
as may be required under the conditions of the IHA; (3) to collect and
report data on the distribution, numbers, movement and behavior of
marine mammals near the seismic operations with special emphasis on
migrating bowhead whales; (4) to support regulatory reporting and
Inupiat communications related to the estimation of impacts of seismic
operations on marine mammals; (5) to monitor the accessibility of
bowhead whales to Inupiat hunters and (6) to document how far west of
seismic activities bowhead whales travel before they return to their
normal migration paths, and if possible, to document how far east of
seismic operations the deflection begins.
The same aerial survey design will be implemented during the summer
(August) and fall (late August-October) period, but during the summer,
the survey grid will be flown twice a week, and during the fall,
flights will be conducted daily. During the early summer, few cetaceans
are expected to be encountered in the nearshore Alaskan Beaufort Sea
where seismic surveys will be conducted. Those cetaceans that are
encountered are expected to be either along the coast (gray whales:
(Maher, 1960; Rugh and Fraker, 1981; Miller et al., 1999; Treacy, 2000)
or seaward of the continental shelf among the pack ice (bowheads: Moore
et al., 1989b; Miller et al., 2002; and belugas: Moore et al., 1993;
Clark et al., 1993; Miller et al., 1999) north of the area where
seismic surveys and drilling activities are to be conducted. During
some years a few gray whales are found feeding in shallow nearshore
waters from Barrow to Kaktovik but most sightings are in the western
part of that area.
During the late summer and fall, the bowhead whale is the primary
species of concern, but belugas and gray whales are also present.
Bowheads and belugas migrate through the Alaskan Beaufort Sea from
summering areas in the central and eastern Beaufort Sea and Amundsen
Gulf to their wintering areas in the Bering Sea (Clarke et al., 1993;
Moore et al., 1993; Miller et al., 2002). Some bowheads are sighted in
the eastern Alaskan Beaufort Sea starting mid-August and near Barrow
starting late August but the main migration does not start until early
September.
The aerial survey procedures will be generally consistent with
those during earlier industry studies (Miller et al., 1997, 1998, 1999;
Patterson et al., 2007). This will facilitate comparison and pooling of
data where appropriate. However, SOI notes that the specific survey
grids will be tailored to SOI's operations and the time of year.
Information on survey procedures can be found in SOI's IHA application.
Survey Design in the Beaufort Sea in Summer
The main species of concern in the Beaufort Sea is the bowhead
whale but small numbers of belugas, and in some years, gray whales, are
present in the Beaufort Sea during summer (see above). Few bowhead
whales are expected to be found in the Beaufort Sea during early
August; however, a reduced aerial survey program is proposed during the
summer prior to seismic operations to confirm the distribution and
numbers of bowheads, gray whales and belugas, because no recent surveys
have been conducted at this time of year. The few bowheads that were
present in the Beaufort Sea during summer in the late 1980s were
generally found among the pack ice in deep offshore waters of the
central Beaufort Sea (Moore and DeMaster, 1998; Moore et al., 2000).
Although gray whales were rarely sighted in the Beaufort Sea prior to
the 1980's (Rugh and Fraker, 1981), sightings appear to have become
more common along the coast of the Beaufort Sea in summer and early
fall (Miller et al., 1999; Treacy 1998, 2000, 2002; Patterson et al.,
2007) possibly because of increases in the gray whale population and/or
reductions in ice cover in recent years. Because no summer surveys have
been conducted in the Beaufort Sea since the 1980s, the information on
summer distribution of cetaceans will be valuable for planning future
seismic or drilling operations. The grid that will be flown in the
summer will be the same grid flown later in the year, but it will be
flown twice a week instead of daily. If ceteceans are encountered in
the vicinity of planned seismic operations, then SOI would consider
flying the survey grid proposed for later in the season, rather than
the early-season survey plan. Surveys will be conducted 2 days/week
until the period one week prior to the start of seismic operations in
the Beaufort Sea. Beginning approximately one week prior to the start
of seismic operations, daily surveys would be initiated and they would
be conducted using the grid shown in Figure 3 in Appendix B of SOI's
IHA application.
Survey Design in the Beaufort Sea in Fall
Aerial surveys during the late August-October period will be
designed to provide mitigation monitoring as required by the IHA. SOI
notes that, if, as in 2006 and 2007, mitigation monitoring is required
to ensure that large aggregations of mother-calf bowheads do not
approach to within the
[[Page 36058]]
120 dB re 1 [mu]Pa (rms) radius from the active seismic operation,
priority will be given to mitigation monitoring to the east of the
seismic operation (see Appendix B, Figure 2). SOI suggests, that, if
permitted by the IHA, it is prepared to conduct some surveys to collect
data on the extent of westward deflection while still monitoring the
120-dB radius to the east of the seismic operation. These surveys will
obtain detailed data (weather permitting) on the occurrence,
distribution, and movements of marine mammals, particularly bowhead
whales, within an area that extends about 100 km (62 mi) to the east of
the primary seismic vessel to a few km west of it, and north to about
65 km (40 mi) offshore. A westward emphasis would obtain the same data
for an area about 100 km (62 mi) to the west of the primary seismic
vessel and about 20 km (12 mi) east of it; again about 65 km (40 mi)
offshore. This site-specific survey coverage will complement the
simultaneous MMS/NMFS National Marine Mammal Laboratory Bowhead Whales
Aerial Survey Program (BWASP) survey coverage of the broader Beaufort
Sea area.
The proposed survey grid will provide data both within and beyond
the anticipated immediate zone of influence of the seismic program, as
identified by Miller et al. (1999). Miller et al. (1999) were not able
to determine how far upstream and downstream (i.e., east and west) of
the seismic operations bowheads began deflecting and then returned to
their ``normal'' migration corridor. That is an important concern for
the Inupiat whalers. SOI notes that the proposed survey grid is not
able to address that concern because of the need to extend flights well
to the east to detect mother-calf pairs before they are exposed to
seismic sounds greater than 120 dB re 1 [mu]Pa.
It is possible that the east-west extent of seismic surveys will
change during the season due to ice or other operational restrictions.
If so, SOI may need to modify the aerial survey grid to maintain
observations to 100 km (62 mi) east (or west) of the seismic survey
area, but the total km/mi of survey that can be conducted each day are
limited by the fuel capacity of the aircraft. The only alternative to
ensure adequate aerial survey coverage over the entire area where
seismic activities might influence bowhead whale distribution is to
space the individual transects farther apart. For each 15-20 km (9.3-
12.4 mi) increase in the east-west size of the seismic survey area, the
spacing between lines will need to be increased by 1 km (0.62 mi) to
maintain survey coverage from 100 km (62 mi) east to 20 km (12.4 mi)
west of the seismic activities (or vice versa). Data from the
easternmost transects of the proposed survey grid will document the
main bowhead whale migration corridor east of the seismic exploration
area and will provide the baseline data on the location of the
migration corridor relative to the coast.
SOI does not propose to fly a smaller ``intensive'' survey grid in
2008/2009. In previous years, a separate grid of 4-6 shorter transects
was flown, whenever possible, to provide additional survey coverage
within about 20 km (12.4 mi) of the seismic operations. This coverage
was designed to provide additional data on marine mammal utilization of
the actual area of seismic exploration and immediately adjacent waters.
The 1996-98 studies showed that bowhead whales were almost entirely
absent from the area within 20 km (12.4 mi) of the active seismic
operation (Miller et al. 1997, 1998, 1999). Thus, the flying-time that
(in the past) would have been expended on flying the intensive grid
will be used to extend the coverage farther to the east and west of the
seismic activity.
Depending on the distance offshore where seismic is being
conducted, the survey grid may not extend far enough offshore to
document whales which could potentially deflect north of the operation.
In this case, SOI plans to extend the north ends of the transects
farther north so that they extend 30-35 km (19-22 mi) north of the
seismic operation and the two most westerly (or easterly depending upon
the survey design) lines will not be surveyed. This will mean that the
survey lines will only extend as far west as the seismic operation or
start as far east as the seismic operations. SOI states that it is not
possible to move the grid north without surveying areas south of the
seismic operation because some whales may deflect south of the seismic
operation and that deflection must be monitored.
If seismic surveys of the Beaufort Sea end while substantial
numbers of bowhead whales are still migrating west, aerial survey
coverage of the area of most recent seismic operations will continue
for several days after seismic surveys have ended. This will provide
``post-seismic'' data on whale distribution for comparison with whale
distribution during seismic periods. These data will be used in
analyses to estimate the extent of deflection during seismic activities
and the duration of any potential deflection after surveys end. Post
seismic coverage will not be conducted if the bowhead migration has
ended by that time, but it is expected that due to freeze-up, seismic
operations will move out of the Beaufort Sea before the end of the
bowhead whale migration.
The survey grid patterns for summer and fall time periods being
proposed by SOI are described in SOI's IHA application.
Joint Industry Studies Program
Chukchi Sea Coastal Aerial Survey
The only recent aerial surveys of marine mammals in the Chukchi Sea
were conducted along coastal areas of the Chukchi Sea to approximately
20 nmi (37 km) offshore in 2006 and 2007 in support of SOI's summer
seismic exploration. These surveys provided data on the distribution
and abundance of marine mammals in nearshore waters of the Chukchi Sea.
Population sizes of several species found they may have changed
considerably since earlier surveys were conducted and their
distributions may have changed because of changes in ice conditions.
SOI plans to conduct an aerial survey program in the Chukchi Sea in
2008 that will be similar to the 2006 and 2007 programs.
Alaskan Natives from several villages along the east coast of the
Chukchi Sea hunt marine mammals during the summer and Native
communities are concerned that offshore oil and gas development
activities such as seismic exploration may negatively impact their
ability to harvest marine mammals. Of particular concern is the
potential impact on the beluga harvest at Point Lay and on future
bowhead harvests at Point Hope, Wainwright and Barrow. Other species of
concern in the Chukchi Sea include the gray whale, bearded, ringed, and
spotted seals, and walrus. The gray whale is expected to be the most
numerous cetacean species encountered during the proposed summer
seismic activities, although beluga whales also occur in the area. The
ringed seal is likely to be the most abundant pinniped species. The
current aerial survey program has been designed to collect distribution
data on cetaceans but will be limited in its ability to collect similar
data on pinnipeds because of aircraft altitude.
The aerial survey program will be conducted in support of the SOI
seismic program in the Chukchi Sea during summer and fall of 2008/2009.
The objectives of the aerial survey will be (1) to address data
deficiencies in the distribution and abundance of marine mammals in
coastal areas of the eastern Chukchi Sea; and (2) to collect and report
data on the distribution, numbers, orientation and behavior of marine
mammals, particularly beluga
[[Page 36059]]
whales, near traditional hunting areas in the eastern Chukchi Sea.
With agreement from hunters in the coastal villages, aerial surveys
of coastal areas to approximately 20 mi (37 km) offshore between Point
Hope and Point Barrow will begin in early- to mid-July and will
continue until mid-November or until seismic operations in the Chukchi
Sea are completed. Weather and equipment permitting, surveys will be
conducted twice per week during this time period. In addition, during
the 2008/2009 field season, SOI will coordinate and cooperate with the
aerial surveys conducted by NMML for MMS and any other groups
conducting surveys in the same region. For a description of the aerial
survey procedures, please see SOI's IHA application.
Acoustic ``Net'' Array: Chukchi Sea
The acoustic ``net'' array used during the 2007 field season in the
Chukchi Sea was designed to accomplish two main objectives. The first
was to collect information on the occurrence and distribution of beluga
whales that may be available to subsistence hunters near villages
located on the Chukchi Sea coast. The second objective was to measure
the ambient noise levels near these villages and record received levels
of sounds from seismic survey activities further offshore in the
Chukchi Sea.
The net array configuration used in 2007 is again proposed for
2008/2009. The basic components are 30 ocean bottom hydrophones (OBH)
systems. Two separate deployments with different placement
configurations are planned. The first deployment will occur in mid-July
immediately following the beluga hunt and will be adjusted to avoid any
interference with the hunt. The initial net array configuration will
include and extend the 2006 configuration (see Figures 8 and 9 in
Appendix B of SOI's application for number of OBHs and locations for
the two deployments). These offshore systems will capture seismic
exploration sounds over large distances to help characterize the sound
transmission properties of larger areas of the Chukchi Sea.
The second deployment will occur in late August at the same time
that all currently deployed systems will be recovered for battery
replacement and data extraction. The second deployment emphasizes the
offshore coverage out to 72 degrees North (80 nm north of Wainwright,
150 nm (172 mi; 278 km) north of Point Lay, and 180 nm (207mi; 333 km)
north of Cape Lizbourne. The primary goal of extending the arrays
further offshore later in the season is to obtain greater coverage of
the central Chukchi Sea to detect vocalization from migrating bowheads
starting in September. The specific geometries and placements of the
arrays are primarily driven by the objectives of (a) detecting the
occurrence and approximate offshore distributions of belugas and
possibly bowhead whales during the July to mid-August period and
primarily by bowhead whales during the mid-August to late-October
period, (b) measuring ambient noise, and (c) measuring received levels
of seismic survey activities. Timing of deployment and final positions
will b subject to weather and ice conditions, based on consultation
with local villages, and carried out to minimize any interference with
subsistence hunting or fishing activities.
Additionally, a set of 4 to 6 OBH systems will be deployed near the
end of the season to collect data throughout the winter.
Acoustic Array: Beaufort Sea
In addition to the continuation of the acoustic net array program
in the Chukchi Sea in 2008/2009, SOI proposes to also continue a
program that deployed directional acoustic recording systems in the
Beaufort Sea. The purpose of the array will be to further understand,
define, and document sound characteristics and propagation resulting
from offshore seismic and other industry operations that may have the
potential to cause deflections of bowhead whales from anticipated
migratory pathways. Of particular interest will be the east-west extent
of deflection (i.e. how far east of a sound source do bowheads begin to
deflect and how far to the west beyond the sound source does deflection
persist). Of additional interest will be the extent of offshore
deflection that occurs.
In previous work around seismic and drill-ship operations in the
Alaskan Beaufort Sea, the primary method for studying this question has
been aerial surveys. Acoustic localization methods provide a
supplementary methods for addressing these questions. As compared with
aerial surveys, acoustic methods have the advantage of providing a
vastly larger number of whale detections, and can operate day or night,
independent of visibility, and to some degree independent of ice
conditions and sea state-all of which prevent or impair aerial surveys.
However, acoustic methods depend on the animals to call, and to some
extent assume that calling rate is unaffected by exposure to industrial
noise. Bowheads do call frequently in the fall, but there is some
evidence that their calling rate may be reduced upon exposure to
industrial sounds, complicating interpretation. The combined use of
acoustic and aerial survey methods will provide information about these
issues.
SOI has contracted with Greeneridge to conduct the whale acoustic
monitoring program using the passive acoustics techniques developed and
used successfully since 2001 for monitoring the bowhead migration past
BP's Northstar oil production facility northwest of Prudhoe Bay. Those
techniques involve using directional autonomous seafloor acoustic
recorders (DASARs) to measure the arrival angles of bowhead calls at
known locations, then triangulating to locate the calling whale.
Thousands, in some years tens of thousands, of whale calls have been
located each year since 2001. The 2008/2009 study will use a new model
of the DASAR similar to those deployed in 2007. Figure 11 in Appendix B
of SOI's IHA application shows potential locations of the DASARs. The
results of these data will be used to determine the extent of
deflection of migrating bowhead whales from the sound sources. More
information on DASARs and this part of SOI's monitoring program can be
found in SOI's IHA application.
Additional Mitigation and Monitoring Measures
In addition to the standard mitigation and monitoring measures
mentioned previously, NMFS is proposing to incorporate additional
mitigation/monitoring measures (such as expanded monitoring-safety
zones for bowhead and gray whales, and having those zones monitored
effectively) into the 2008/2009 IHA to ensure that impacts on marine
mammals are at the lowest level practicable. The additional mitigation
measures are specific for the SOI seismic project, in part because SOI
incorporated monitoring measures in the 4MP document that makes this
monitoring practicable. It should be recognized that these mitigation/
monitoring measures do not establish NMFS policy applicable to other
projects or other locations under NMFS' jurisdiction, as each
application for an IHA is context-specific. These measures have been
developed based upon available data specific to the project areas. NMFS
and MMS intend to collect additional information from all sources,
including industry, non-governmental organizations, Alaska Natives and
other federal and state agencies regarding measures necessary for
effectively monitoring marine mammal populations, assessing impacts
from seismic on marine mammals, and
[[Page 36060]]
determining practicable measures for mitigating those impacts. MMS and
NMFS anticipate that mitigation measures applicable to future seismic
and other activities may change and evolve based on newly-acquired
data.
Reporting
Daily Reporting
In its IHA application, SOI proposes to collect, via the aerial
flights, unanalyzed bowhead sighting and flightline data which will be
exchanged between MMS and SOI on a daily basis during the field season.
NMFS is proposing that each team will also submit its sighting
information to NMFS in Anchorage each day. After the SOI and MMS data
files have been reviewed and finalized, they will be shared in digital
form.
Interim Report
The results of the 2008 SOI vessel-based monitoring, including
estimates of take by harassment, will be presented in the ``90 day''
and final Technical Report as required by NMFS under IHAs. SOI proposes
that the Technical Report will include: (1) summaries of monitoring
effort: total hours, total distances, and distribution through study
period, sea state, and other factors affecting visibility and
detectability of marine mammals; (2) analyses of the effects of various
factors influencing detectability of marine mammals: sea state, number
of observers, and fog/glare; (3) species composition, occurrence, and
distribution of marine mammal sightings including date, water depth,
numbers, age/size/gender categories, group sizes, and ice cover; (4)
sighting rates of marine mammals versus operational state (and other
variables that could affect detectability); (5) initial sighting
distances versus operational state; (6) closest point of approach
versus seismic state; (7) observed behaviors and types of movements
versus operational state; (8) numbers of sightings/individuals seen
versus operational state; (9) distribution around the drilling vessel
and support vessels versus operational state; and (10) estimates of
take based on (a) numbers of marine mammals directly seen within the
relevant zones of influence (160 dB, 180 dB, 190 dB (if SPLs of that
level are measured)), and (b) numbers of marine mammals estimated to be
there based on sighting density during daytime hours with acceptable
sightability conditions. This report will be due 90 days after
termination of the 2008 open water season and will include the results
from any seismic work conducted in the Chukchi/Beaufort Seas in 2008
under the previous IHA.
Comprehensive Monitoring Reports
In November, 2007, SOI (in coordination and cooperation with other
Arctic seismic IHA holders) released a final, peer-reviewed edition of
the 2006 Joint Monitoring Program in the Chukchi and Beaufort Seas,
July-November 2006 (LGL, 2007). This report is available for
downloading on the NMFS website (see ADDRESSES). A draft comprehensive
report for 2007 was provided to NMFS and those attending the NMFS/MMS
Arctic Ocean open water meeting in Anchorage, AK on April 14-16, 2008.
Based on reviewer comments made at that meeting, SOI is currently
revising this report and plans to make it available to the public
shortly.
Following the 2008 open water season, a comprehensive report
describing the proposed acoustic, vessel-based, and aerial monitoring
programs will be prepared. The 2008 comprehensive report will describe
the methods, results, conclusions and limitations of each of the
individual data sets in detail. The report will also integrate (to the
extent possible) the studies into a broad based assessment of industry
activities and their impacts on marine mammals in the Beaufort Sea
during 2008 (work conducted in 2009 under the proposed 2008/2009 IHA
will be analyzed in a 2009 comprehensive report). The 2008 report will
form the basis for future monitoring efforts and will establish long
term data sets to help evaluate changes in the Beaufort/Chukchi Sea
ecosystems. The report will also incorporate studies being conducted in
the Chukchi Sea and will attempt to provide a regional synthesis of
available data on industry activity in offshore areas of northern
Alaska that may influence marine mammal density, distribution and
behavior.
This comprehensive report will consider data from many different
sources including two relatively different types of aerial surveys;
several types of acoustic systems for data collection (net array,
passive acoustic monitoring, vertical array, and other acoustical
monitoring systems that might be deployed), and vessel based
observations. Collection of comparable data across the wide array of
programs will help with the synthesis of information. However,
interpretation of broad patterns in data from a single year is
inherently limited. Much of the 2008 data will be used to assess the
efficacy of the various data collection methods and to establish
protocols that will provide a basis for integration of the data sets
over a period of years.
Endangered Species Act (ESA)
Under section 7 of the ESA, the NMFS has begun consultation with
MMS on the proposed seismic survey activities in the Beaufort and
Chukchi seas during 2008/2009. NMFS will also consult on the issuance
of the IHA under section 101(a)(5)(D) of the MMPA to SOI for this
activity. Consultation will be concluded prior to NMFS making a
determination on the issuance of an IHA.
National Environmental Policy Act (NEPA)
In 2006, the MMS prepared Draft and Final Programmatic
Environmental Assessments (PEAs) for seismic surveys in the Beaufort
and Chukchi Seas. Availability of the Draft and Final PEA was noticed
by NMFS in several Federal Register notices regarding issuance of IHAs
to SOI and others. NMFS was a cooperating agency in the preparation of
the MMS PEA. On November 17, 2006, NMFS and MMS announced that they
were jointly preparing a Draft Programmatic Environmental Impact
Statement (PEIS) to assess the impacts of MMS' annual authorizations
under the Outer Continental Shelf (OCS) Lands Act to the U.S. oil and
gas industry to conduct offshore geophysical seismic surveys in the
Chukchi and Beaufort seas off Alaska, and NMFS' authorizations under
the MMPA to incidentally harass marine mammals while conducting those
surveys. On March 30, 2007, the Environmental Protection Agency (EPA)
noticed the availability for comment of the NMFS/MMS Draft PEIS. A
Final PEIS has not been completed. In order to meet NMFS' NEPA
requirements for the proposed IHA to SOI, NMFS is preparing a
supplement to the 2006 Final PEA which incorporates by reference the
2006 Final PEA and other related documents. Upon completion, a copy of
this Supplemental EA will be available upon request.
Preliminary Determinations
Based on the information provided in SOI's application, this
document, the MMS 2006 Final PEA for Arctic Seismic Surveys, the 2006
and 2007 Comprehensive Monitoring Reports by SOI and others, and NMFS'
2008 Final Supplemental EA, NMFS has preliminarily determined that the
impact of SOI conducting seismic surveys in the northern Chukchi Sea
and eastern and central Beaufort Sea in 2008/2009 will have no more
than a negligible impact on marine mammals and that there will not be
any
[[Page 36061]]
unmitigable adverse impacts to subsistence communities, provided the
mitigation measures described in this document are implemented (see
Mitigation).
For reasons explained previously in this document, NMFS has
preliminarily determined that no take by serious injury, death or
stranding is anticipated by, or authorized to, SOI's 2008/2009 seismic
survey activities, and the potential for temporary or permanent hearing
impairment is low and will be avoided through the incorporation of the
mitigation measures mentioned in this document. The best scientific
information indicates that an auditory injury is unlikely to occur as
apparently sounds need to be significantly greater than 180 dB for
injury to occur. NMFS has preliminarily determined that exposure to
several seismic pulses at received levels near 200-205 dB (rms) might
result in slight TTS in hearing in a small odontocete. Seismic pulses
with received levels of 200-205 dB or more are usually restricted to a
radius of no more than 200 m (656 ft) around a seismic vessel operating
a large array of airguns. For baleen whales, while there are no data,
direct or indirect, on levels or properties of sound that are required
to induce TTS, there is a strong likelihood that baleen whales
(bowheads, gray whales and humpback whales) would avoid the approaching
airguns (or vessel) before being exposed to levels high enough for
there to be any possibility of onset of TTS. For pinnipeds, information
indicates that for single seismic impulses, sounds would need to be
higher than 190 dB rms for TTS to occur while exposure to several
seismic pulses indicates that some pinnipeds may incur TTS at somewhat
lower received levels than do small odontocetes exposed for similar
durations. Therefore, the requirement for MMOs to monitor safety zones
(180 dB for cetaceans, 190 dB for pinnipeds) and power-down or shutdown
arrays even at this distance and the increasing effectiveness of an MMO
seeing a marine mammal prior to entering a close-in zone where auditory
injury could occur indicates to NMFS that the 180 dB and 190-dB safety
zones for cetaceans and pinnipeds respectively, provides a sufficient
buffer to prevent PTS in marine mammals.
NMFS has also preliminarily determined that only small numbers of
marine mammals will be harassed by SOI's 2008 seismic and shallow
hazard programs. As discussed previously, the species most likely to be
harassed during seismic surveys in the Arctic Ocean area is the ringed
seal, with a total ``best estimate'' of 13,256 animals being
``exposed'' to sound levels of 160 dB or greater(6,951 animals in the
Chukchi Sea and 6,305 animals in the Beaufort Sea)(see Table 1). As
explained previously, this does not mean that this is the number of
ringed seals that will actually have a behavioral reaction to the
noise, rather it is simply the best estimate of the number of animals
that potentially could have a behavioral modification due to the noise.
For example Moulton and Lawson (2002) indicate that most pinnipeds
exposed to seismic sounds lower than 170 dB do not visibly react to
that sound; pinnipeds are not likely to react to seismic sounds unless
they are greater than 170 dB re 1 microPa (rms). In addition as
discussed previously, these estimates are calculated based upon line
miles of survey effort (also animal density and the calculated zone of
influence), the resulting take estimate numbers tend to be highly
inflated, because animals that might have been affected (taken) are
likely to have moved out of the area to avoid additional annoyance from
the seismic sounds (assuming they were taken in the first place). As a
result, NMFS believes that these ``exposure'' estimates for pinnipeds
are conservative and seismic and shallow hazard surveys will actually
affect significantly less than 5 percent of the Beaufort and Chukchi
Sea ringed seal populations. This preliminary finding also applies to
other pinniped species in the Arctic.
Even if the estimate of 13,256 ringed seals being behaviorally
harassed is not a small number in absolute terms, it is relatively
small, representing only about 5.3 percent of the regional stock size
of that species (249,000), if each ``exposure'' at 160 dB represents an
individual ringed seal that has reacted to that sound and less if a
higher SPL is required for a behavioral reaction (as is expected) or
animals moved out of the seismic area. As a result, we believe that
these ``exposure'' estimates are conservative and seismic and shallow
hazard surveys will actually affect significantly less than 5 percent
of the Beaufort and Chukchi Sea ringed seal populations. This finding
also applies to other pinniped species in the Arctic.
The estimated number of Level B harassment takes represented as
``exposures'' during SOI's seismic and shallow hazard surveys in the
Beaufort and Chukchi seas is 297 beluga (63 in the Chukchi Sea, 234 in
the Beaufort Sea) and 1,540 bowheads (9 in the Chukchi Sea and 1,531 in
the Beaufort Sea). The Level B harassment ``take'' estimate represents
less than 1 percent of the combined Beaufort and Chukchi Seas beluga
stock size of 42,968 (39,258 in the Beaufort Sea; 3,710 in the Chukchi
Sea), a relatively small number. For bowhead whales, this Level B
harassment ``take'' estimate represents between 12 percent (based on
13,326 bowheads which assumes a 3.4 percent annual population growth
rate from the 2001 estimate) and 14 percent of the Bering-Chukchi-
Beaufort Seas bowhead population (based on the 2001 population estimate
of 10,545 animals). However, NMFS currently estimates that this
population percentage estimate will be lower because SOI has
significantly reduced its planned days of seismic surveys in the
Beaufort Sea to only 20 days (September 25 to about October 15th or
when surveys are curtailed by ice).
While these exposure numbers may represent a somewhat sizable
portion of the population size of bowhead whales (12-14 percent), NMFS
believes that the estimated number of bowhead exposures overestimate
actual takings for the following reasons: (1) SOI plans to concentrate
its 3D seismic survey program in 2008 in the Lease Sale 193 area of the
Chukchi Sea and only move into the Beaufort Sea after the bowhead
subsistence hunt is completed (and a sizeable portion of the bowhead
population will have migrated past SOI's planned seismic location by
that time), and (2) the proposed shallow hazard survey activities would
occur in the Chukchi and Beaufort seas at a time when bowheads are
mostly concentrated in the Canadian Beaufort Sea. As a result, NMFS has
preliminarily determined that relatively few bowhead whales will be
taken and that only small numbers of marine mammals will be harassed by
SOI's 2008 seismic and shallow hazard programs.
Therefore, NMFS has preliminarily determined that the short-term
impact of conducting seismic surveys in the U.S. Chukchi and Beaufort
seas may result, at worst, in a temporary modification in behavior by
certain species of marine mammals. While behavioral and avoidance
reactions may be made by these species in response to the resultant
noise, this behavioral change is expected to have a negligible impact
on the animals. While the number of potential incidental harassment
takes will depend on the distribution and abundance of marine mammals
(which vary annually due to variable ice conditions and other factors)
in the area of seismic operations, the number of potential harassment
takings is estimated to be small (see Estimated Takes for NMFS'
analysis). In addition, for reasons described previously, injury
(temporary
[[Page 36062]]
or permanent hearing impairment) and/or mortality is unlikely and will
be avoided through the incorporation of the mitigation measures
mentioned in this document and required by the authorization. No
rookeries, mating grounds, areas of concentrated feeding, or other
areas of special significance for marine mammals occur within or near
the planned area of operations during the season of operations.
Finally, NMFS has preliminarily determined that the proposed
seismic activity by SOI in the northern Chukchi Sea and central and
eastern Beaufort Sea in 2008/2009 will not have an unmitigable adverse
impact on the subsistence uses of bowhead whales and other marine
mammals. This preliminary determination is supported by the information
in this Federal Register Notice, including: (1) Seismic activities in
the Chukchi Sea will not begin until after July 20 by which time the
spring bowhead hunt is expected to have ended; (2) that the fall
bowhead whale hunt in the Beaufort Sea will either be governed by a CAA
between SOI and the AEWC and village whaling captains or by mitigation
measures to protect subsistence hunting of marine mammals contained in
the IHA; (3) the CAA or IHA conditions will significantly reduce
impacts on subsistence hunters to ensure that there will not be an
unmitigable adverse impact on subsistence uses of marine mammals; (4)
while it is possible that accessibility to belugas during the spring
subsistence beluga hunt could be impaired by the survey, it is unlikely
because very little of the proposed survey is within 25 km (15.5 mi) of
the Chukchi Sea coast, meaning the vessel will usually be well offshore
and away from areas where seismic surveys would influence beluga
hunting by communities; and (5) because seals (ringed, spotted,
bearded) are hunted in nearshore waters and the seismic survey will
remain offshore of the coastal and nearshore areas of these seals where
natives would harvest these seals, it should not conflict with harvest
activities.
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to SOI for conducting a seismic survey in the northern
Chukchi Sea and central and eastern Beaufort Sea in 2008/2009, provided
the previously mentioned mitigation, monitoring, and reporting
requirements are incorporated.
Dated: June 20, 2008.
P. Michael Payne,
Acting Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. E8-14393 Filed 6-24-08; 8:45 am]
BILLING CODE 3510-22-S