[Federal Register: May 12, 2006 (Volume 71, Number 92)]
[Notices]
[Page 27685-27695]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr12my06-57]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[I.D. 042606H]
Small Takes of Marine Mammals Incidental to Open-water Seismic
Operations in the Chukchi Sea
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; receipt of application and proposed incidental take
authorization; request for comments.
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SUMMARY: NMFS has received an application from Conoco Phillips Alaska,
Inc, (Conoco) for an Incidental Harassment Authorization (IHA) to take
small numbers of marine mammals, by harassment, incidental to
conducting open-water seismic data aquisition in the Chukchi Sea during
the summer of 2006. Under the Marine Mammal Protection Act (MMPA), NMFS
is requesting comments on its proposal to issue an authorization to
Conoco to incidentally take, by harassment, small numbers of several
species of marine mammals during the seismic survey.
DATES: Comments and information must be received no later than June 12,
2006.
ADDRESSES: Comments on the application should be addressed to Steve
Leathery, Chief, Permits, Conservation and Education Division, Office
of Protected Resources, National Marine Fisheries Service, 1315 East-
West Highway, Silver Spring, MD 20910-3225. The mailbox address for
providing email comments is PR1.042606H@noaa.gov. NMFS is not
responsible for e-mail comments sent to addresses other than the one
provided here. Comments sent via e-mail, including all attachments,
must not exceed a 10-megabyte file size.
A copy of the application containing a list of the references used
in this document may be obtained by writing to the address specified
above, telephoning the contact listed below (see FOR FURTHER
INFORMATION CONTACT), or visiting the internet at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm
.
Documents cited in this notice may be viewed, by appointment,
during regular business hours, at the aforementioned address.
FOR FURTHER INFORMATION CONTACT: Jolie Harrison, Office of Protected
Resources, NMFS, (301) 713-2289, ext 166.
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
[[Page 27686]]
authorization is provided to the public for review.
Authorization shall be granted if NMFS finds that the taking will
have a negligible impact on the species or stock(s), will not have an
unmitigable adverse impact on the availability of the species or
stock(s) for subsistence uses, and that 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 issuance of the authorization.
Summary of Request
On February 2, 2006, NMFS received an application from Conoco for
the taking, by harassment, of several species of marine mammals
incidental to conducting open-water seismic data aquisition in the
Chukchi Sea from July through November, 2006. Seismic surveys such as
the one proposed here provide accurate data on the location, extent,
and properties of hydrocarbon resources as well as information on
shallow geologic hazards and seafloor geotechnical properties to
explore, develop, produce, and transport hydrocarbons safely,
economically, and in an environmentally safe manner. This information
is utilized by both the oil and gas industry and the Minerals
Management Service (MMS).
Description of the Activity
Conoco seeks an IHA for conducting open-water seismic surveys
between July 1 and November 30, 2006. The seismic vessel planned for
use is the MV Patriot. Mobilization of operations will occur in mid-
July, and seismic operations are proposed to begin in late July. Open
water seismic operations are ordinarily confined to no more than this
five-month period because of the timing of ice melt and formation,
which typically occurs during a four to five month period. The
geographic region of activity encompasses a 2500-3600 km\2\-area (965-
1390 mi\2\-area) in the northeastern Chukchi Sea. The approximate
boundaries of the region are within 158[deg]00' W. and 169[deg]00' W.
and 69[deg]00' N. and 73[deg]00' N. with eastern boundary located
parallel to the coast of Alaska, north of Point Hope to Point Barrow,
and ranging 40-180 km (25-112 mi) off the coast. The nearest
approximate point of the project to Point Hope is 74 km (46 mi), Point
Lay 90 km (56 mi), Wainwright 40 km (25 mi), and Barrow 48 km (30 mi).
Water depths are typically less than 50 m (164 ft).
Conoco anticipates a work schedule of approximately 90-100 days to
complete the planned 16,576 km (10,300 mi) of trackline, with about 30-
percent downtime due to weather, ice conditions, repairs etc. In
addition to the primary activity of the seismic vessel, there will also
be support vessels. A supply vessel and a fuel bunkering vessel will be
employed to bring supplies to the seismic vessel. The seismic crew will
most likely be changed out by helicopter and fixed-wing support may be
used to report ice conditions if necessary.
Description of Marine 3-D Seismic Data Acquisition
In the seismic method proposed here, 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 serves 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.
Vessel and Seismic Source Specifications
The MV Patriot is owned by Western Geco. The MV Patriot has a
length of 78 m (256 ft), a beam of 17 m (56 ft), a maximum draft of 5.9
m (19.4 ft), and 3586 gross tonnage. During seismic operations, the MV
Patriot typically travels at 4-5 knots (7.4-9.2 km/hr). The MV
Patriot's average speed when not using seismic is 12 - 15 knots (22 -28
km/hr).
The energy source for the proposed activity will be air gun array
systems towed behind the vessel. There will be six to eight cables
approximately 4 km (2.5 mi) in length spaced 100 m (328 ft) apart. Each
source array consists of identically tuned Bolt gun sub-arrays
operating at 2000 pounds per square inch (psi) air pressure operating
about 8 m (26 ft) below the surface. The dominant frequency components
are in the range of 5-70 Hz, the source level at those frequencies is
about 209 dB, and the pulse length is 50 ms. The arrays will fire on
interleaved 50-meter (164-ft) intervals (i.e., approximately every 15
seconds) and they are designed to focus energy in the downward
direction. The proposal is to have two air-gun arrays, each
approximately 1695\3\-in size (27,776-cm\3\)(and spaced approximately
50 m (164 ft) apart). Together the two arrays will total approximately
3390\3\ in (55,552-cm\3\). The airgun array will fire approximately
every 25 m (82 ft) as the vessel is traveling at 4 to 5 knots (7.4-9.2
km/hr). The sub-array is composed of six tuning elements; two 2-gun
clusters and four single guns. The clusters have their component guns
arranged in a fixed side-by-side fashion with the distance between the
gun ports set to maximize the bubble suppression effects of clustered
guns. A near-field hydrophone is mounted about 1 meter (3.28 ft) above
[[Page 27687]]
each gun station (one phone is used per cluster), one depth transducer
per position is mounted on the gun's ultrabox, and a high pressure
transducer is mounted at the aft end of the sub-array to monitor high
pressure air supply. All the data from these sensors are transmitted to
the vessel for input into the onboard systems and recording to tape.
See Appendix A of the application for additional information on the
array configuration.
Conoco will also operate two additional pieces of equipment
throughout the planned study that emit sound at a frequency at or near
that which a marine mammal could hear. The Simrad EA500 echo-sounder
and the beam is directed downwards and can be up to 33[deg] wide. The
Sonardyne SIPS-2 acoustic positioning system operates at 55-110 kHz,
omnidirectional.
Characteristics of Airgun Pulses
Discussion of the characteristics of airgun pulses has been
provided in the application and in previous Federal Register notices
(see 69 FR 31792, June 7, 2004 or 69 FR 34996, June 23, 2004).
Reviewers are referred to those documents for additional information.
Description of Marine Mammals and Habitat Affected by the Activity
A detailed description of the Beaufort and Chukchi sea ecosystems
and their associated marine mammals can be found in several documents
(Corps of Engineers, 1999; NMFS, 1999; MMS, 2006, 1996 and 1992). MMS'
Programmatic Environmental Assessment (PEA) - Arctic Ocean Outer
Continental Shelf Seismic Surveys - 2006 may be viewed at: http://www.mms.gov/alaska/
.
Marine Mammals
A total of five cetacean species (bowhead, beluga, killer, gray,
and minke whales) and three pinniped species (ringed, bearded, and
spotted seals) are known to occur in the project area. Both minke
whales and killer whales are very uncommon in the area and are not
expected to be encountered during the seismic survey. One of the
species, the bowhead whale, is listed as Endangered under the
Endangered Species Act (ESA). Polar bears and the Pacific walrus also
occur in the project area, but the U.S. Fish and Wildlife Service is
responsible for both of these species and is conducting a separate
consultation to ensure compliance with the MMPA, and, therefore, they
are not discussed further in this document.
Table 1 includes estimated abundances and densities for the species
expected to be potentially encountered during Conoco's seismic surveys.
Abundance and density information for bowhead, gray, and beluga whales
are based on the estimates provided in LGL's Healy Arctic Cruise
Application (2005). In the Conoco application, ringed seal density was
based on Bengston et al.'s (2005) estimates of density in the Chukchi
Sea recorded in 1999 and 2000. Also in the Conoco application, bearded
seal densities were obtained by adjusting the density for ringed seals
based on the ratio of bearded to ringed seals observed during surveys
in the Chukchi Sea by Brueggerman et al. (1990, 1991). Both the bearded
and ringed seal densities are likely high, since Bengston et al. (2005)
surveys included an area south of the project area, where they reported
ringed and bearded seal densities were considerablye higher than north
of Point Hope, which corresponds to the seismic project area.
Accordingly, NMFS also provides the densities estimated by LGL (2005)
for comparison. Additional information regarding the distribution of
these species and how the estimated densities were calculated may be
found in Conoco's application and NMFS' Updated Species Reports at:
(http://www.nmfs.noaa.gov/pr/readingrm/MMSARS/2005alaskasummarySARs.pdf
).
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Estimated take Percent of
Species Abundance Density (w/o mitigation) Stock
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bowhead Whale Balaena mysticetus 10,545 0.0064 418 4.0
Beluga Whale Delphinapterus leucas 42,968 0.0034 361 0.8
Gray Whale Eschiritius robustus 18,813 0.0045 481 2.6
Killer Whale Orcinus orca >100 N/A 0 0.0
Minke Whale Balaenoptera acutorostrata No est. available N/A 0 0.0
Ringed Seal Phoca hispida >249,000 0.25 - 0.53 56,458 10.7 - 22.7
Bearded Seal Erignathuis barbatus 250,000 - 300,000 0.01 - 0.24 25,567 0.5 - 9.3
Spotted Seal Phoca largha 59,214 0.0001 100 0.2
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Potential Effects on Marine Mammals
Summary of Potential Effects of Airgun Sounds 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. NMFS does not expect any takings to
result from operations of the other sound sources discussed
(echosounder and acoustic positioning system). For the echosounder ,
produced sounds are beamed downward, the beam is narrow, the pulses are
extremely short, and the sound source is relatively low, and with the
acoustic postioning system, the beam is spherical, but the sound source
is relatively low. Additionally, in the case of both of these pieces of
equipment, the small area ensonified to a level that could potentially
disturb marine mammals is entirely subsumed by the louder levels of
airgun noise (which will also be running when these equipment are
used.)
As outlined in previous NMFS documents, the effects of noise on
marine mammals are highly variable, and can be categorized as follows
(based on Richardson et al., 1995):
(1) The noise may be too weak to be heard at the location of the
animal (i.e., lower than the prevailing ambient noise level, the
hearing threshold of the animal at relevant frequencies, or both);
(2) The noise may be audible but not strong enough to elicit any
overt behavioral response;
(3) The noise may elicit reactions of variable conspicuousness and
variable relevance to the well being of the marine mammal; these can
range from temporary alert responses to active avoidance reactions such
as vacating an area at least until the noise event ceases;
(4) Upon repeated exposure, a marine mammal may exhibit diminishing
responsiveness (habituation), or disturbance effects may persist; the
latter is most likely with sounds that are highly variable in
characteristics, infrequent and unpredictable in
[[Page 27688]]
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 Surveys on Marine Mammals
NMFS anticipates that the effects of Conoco's seismic surveys on
marine mammals will primarily consist of behavioral disturbance,
masking (the animals cannot hear the other sounds around them as well
while the seismic noise is present), TTS (temporary damage to the
auditory tissues), and low-level physiological effects. NMFS is also
currently analyzing the potential effects of issuing IHAs to two other
companies that have proposed seismic surveys in the Chukchi Sea during
the same general time period, and is considering the possibility and
effects of marine mammals being exposed to seismic pulses from multiple
vessels at the same time.
When the received levels of noise exceed some behavioral reaction
threshold, cetaceans will show disturbance reactions. The levels,
frequencies, and types of noise that will elicit a response vary
between and within species, individuals, context, 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 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, may be less likely than resting
animals to show overt behavioral reactions, unless the disturbance is
directly threatening.
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, less than 7 percent)) 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 (Western Geophysical, 2000).
Hearing damage is not expected to occur during the Conoco seismic
survey project. 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, but TTS is a theoretical possibility
for animals within a few hundred meters of the source (Richardson et
al., 1995). However, planned monitoring and mitigation measures
(described later in this document) are 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, as mentioned
previously, bowhead whales avoid an area many kilometers in radius
around ongoing seismic operations, precluding any possibility of
hearing damage.
Reported species-specific responses of the marine mammals likely to
be encountered in the proposed survey area to seismic pulses are
discussed later in this section. Masking, TTS, and behavioral
disturbance as a result of exposure to low frequency sounds have been
discussed in detail in other NMFS documents (70 FR 47797), as well as
the 2006 MMS PEA.
In addition to TTS, exposure to intense seismic sounds is likely to
result in other physiological changes that have other consequences for
the health and ecological fitness of marine mammals. There is mounting
evidence that wild animals respond to human disturbance in the same way
that they respond to predators (Beale and Monaghan, 2004; Frid, 2003;
Frid and Dill, 2002; Gill et al., 2000; Gill and Sutherland, 2001;
Harrington and Veitch, 1992; Lima, 1998; Romero, 2004). These responses
manifest themselves as interruptions of essential behavioral or
physiological events, alteration of an animal's time or energy budget,
or stress responses in which an animal perceives human activity as a
potential threat and undergoes physiological changes to prepare for a
flight or fight response or more serious physiological changes with
chronic exposure to stressors (Frid and Dill, 2002; Romero, 2004;
Sapolsky et al., 2000; Walker et al., 2005).
Classic stress responses begin when an animal's central nervous
system perceives a potential threat to its homeostasis. That perception
triggers stress responses regardless of whether a stimulus actually
threatens the animal; the mere perception of a threat is sufficient to
trigger a stress response (Sapolsky et al., 2005; Seyle, 1950). Once an
animal's central nervous system perceives a threat, it develops a
biological response or defense that consists of a combination of the
four general biological defense responses: behavioral responses,
autonomic nervous system responses, neuroendocrine responses, or immune
response.
The physiological mechanisms behind stress responses involving the
hypothalamus-pituitary-adrenal glands have been well-established
through controlled experiment in the laboratory and natural settings
(Korte et al., 2005; McEwen and Seeman, 2000; Moberg, 1985; 2000;
Sapolsky et al., 2005). Relationships between these physiological
processes, animal behavior, neuroendocrine responses, immune responses,
inhibition of reproduction (by suppression of pre-ovulatory luteinizing
hormones), and the costs of stress responses have also been documented
through controlled experiment in both laboratory and free-living
animals (for examples see, Holberton et al., 1996; Hood et al., 1998;
Jessop et al., 2003; Krausman et al., 2004; Lankford et al., 2005;
Reneerkens et al., 2002; Thompson and Hamer, 2000; Tilbrook et al.,
2000).
The available evidence suggests that: with the exception of
unrelieved pain or extreme environmental conditions, in
[[Page 27689]]
most animals (including humans) chronic stress results from exposure to
a series of acute stressors whose cumulative biotic costs produce a
pathological or pre-pathological state in an animal. The biotic costs
can result from exposure to an acute stressor or from the accumulation
of a series of different stressors acting in concert before the animal
has a chance to recover.
Although few of these responses have been explicitly identified in
marine mammals, they have been identified in other vertebrate animals
and every vertebrate mammal that has been studied, including humans.
Because of the physiological similarities between marine mammals and
other mammal species, NMFS believes that acoustic energy sufficient to
trigger onset TTS is likely to initiate physiological stress responses.
More importantly, NMFS believes that marine mammals might experience
stress responses at received levels lower than those necessary to
trigger onset TTS, and that some of these stress responses rise to the
level of Harassment.
The following species summaries are provided by NMFS to facilitate
understanding of our knowledge of impulsive noise impacts on the
principal marine mammal species that are expected to be affected.
Bowhead Whales
Seismic pulses are known to cause strong avoidance reactions by
many of the bowhead whales occurring within a distance of a few
kilometers, including changes in surfacing, respiration and dive
cycles, and may sometimes cause avoidance or other changes in bowhead
behavior at considerably greater distances (Richardson et al., 1995;
Rexford, 1996; MMS, 1997). Studies conducted prior to 1996 (Reeves et
al., 1984, Fraker et al., 1985, Richardson et al., 1986, Ljungblad et
al., 1988) have reported that, when an operating seismic vessel
approaches within a few kilometers, most bowhead whales exhibit strong
avoidance behavior and changes in surfacing, respiration, and dive
cycles. In these studies, bowheads exposed to seismic pulses from
vessels more than 7.5 km (4.7 mi) away rarely showed observable
avoidance of the vessel, but their surface, respiration, and dive
cycles appeared altered in a manner similar to that observed in whales
exposed at a closer distance (Western Geophysical, 2000). In three
studies of bowhead whales and one of gray whales during this period,
surfacing-dive cycles were unusually rapid in the presence of seismic
noise, with fewer breaths per surfacing and longer intervals between
breaths (Richardson et al.,1986; Koski and Johnson,1987; Ljungblad et
al.,1988; Malme et al.,1988). This pattern of subtle effects was
evident among bowheads 6 km (3mi) to at least 73 km (3.7 to 45.3 mi)
from seismic vessels. However, in the pre-1996 studies, active
avoidance usually was not apparent unless the seismic vessel was closer
than about 6 to 8 km (3.7 to 5.0 mi)(Western Geophysical, 2000).
The proposed seismic survey will occur during a time when bowhead
whales are migrating west from Canada back across the North Slope of
Alaska. Results from the 1996-1998 BP and Western Geophysical seismic
program monitoring in the Beaufort Sea indicate that most 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 at which approaching bowheads begin to deflect, but this may
be on the order of 35 km (21.7 mi). It is also uncertain how far beyond
(west of) the seismic operation the seaward deflection persists (Miller
et al., 1999). Although very few bowheads approached within 20 km (12.4
mi) of the operating seismic vessel, the number of bowheads sighted
within that area returned to normal within 12-24 hours after the airgun
operations ended (Miller et al., 1999).
Inupiat whalers believe that migrating bowheads are sometimes
displaced at distances considerably greater than suggested by pre-1996
scientific studies (Rexford, 1996) previously mentioned in this
document. Also, whalers believe that avoidance effects can extend out
to distances on the order of 30 miles (48.3 km), and that bowheads
exposed to seismic also are ``skittish'' and more difficult to
approach. The ``skittish'' behavior may be related to the observed
subtle changes in the behavior of bowheads exposed to seismic pulses
from distant seismic vessels (Richardson et al., 1986).
Gray Whales
The reactions of gray whales to seismic pulses are similar to those
documented for bowheads during the 1980s. Migrating gray whales along
the California coast were noted to slow their speed of swimming, turn
away from seismic noise sources, and increase their respiration rates.
Malme et al. (1983, 1984, 1988) concluded that approximately 50 percent
of the migrating gray whales showed avoidance when the average received
pulse level was 170 dB (re 1 microPa). By some behavioral measures,
clear effects were evident at average pulse levels of 160dB or greater;
less consistent results were suspected at levels of 140-160 dB. Recent
research on migrating gray whales showed responses similar to those
observed in the earlier research when the source was moored in the
migration corridor 2 km (1.2 mi) from shore. However, when the source
was placed offshore (4 km (2.5 mi) from shore) of the migration
corridor, the avoidance response was not evident on track plots (Tyack
and Clark, 1998).
Beluga
The beluga is the only species of toothed whale (odontocete)
expected to be encountered in the Beaufort Sea. Belugas have poor
hearing thresholds at frequencies below 200 Hz, where most of the
energy from airgun arrays is concentrated. Their thresholds at these
frequencies (as measured in a captive situation), are 125 dB re 1
microPa or more depending upon frequency (Johnson et al., 1989).
Although not expected to be significantly affected by the noise, given
the high source levels of seismic pulses, airgun sounds sometimes may
be audible to belugas at distances of 100 km (62.1 mi) (Richardson and
Wursig, 1997), and perhaps further if actual low-frequency hearing
thresholds in the open sea are better than those measured in captivity
(Western Geophysical, 2000). The reaction distance for belugas,
although presently unknown, is expected to be less than that for
bowheads, given the presumed poorer sensitivity of belugas than that of
bowheads for low-frequency sounds.
As noted in the MMS PEA, effects on the immune system from seismic
pulses have been documented by Romano et al. (2004). They summarized
that ``anthropogenic sound is a potential ``stressor'' for marine
mammals. Not only can loud or persistent noise impact the auditory
system of cetaceans, it may impact health by bringing about changes in
immune function, as has been shown in other mammals'' These authors
identified neural immune measurements that may be ``implicated as
indicates of stress in a beluga and bottlenose dolphin that were either
released acutely or changed over time during experimental period.''
Specifically, they found significant increases in aldosterone and a
significant decrease in monocytes in a bottlenose dolphin after
exposure to single impulsive sounds (up to 200 kiloPascals (kPa)) from
a seismic water gun. Neural-immune changes following
[[Page 27690]]
exposure to single pure tones (up to 201 dB re 1 microPa) resembling
sonar pings were minimal, but changes were observed over time. A beluga
whale exposed to single underwater impulses produced by a seismic water
gun had significantly higher norepinephrine, dopamine and epinephrine
levels after high-level sound exposure (>100 kPa) as compared with low-
level exposures (< 100kPa) or controls and increased with increasing
sound levels.
Ringed, Spotted and Bearded Seals
No detailed studies of reactions by seals to noise from open water
seismic exploration have been published (Richardson et al., 1995).
However, there are some data on the reactions of seals to various types
of impulsive sounds (LGL and Greeneridge, 1997, 1998, 1999a; J. Parsons
as quoted in Greene et al., 1985; Anon., 1975; Mate and Harvey, 1985).
These studies indicate that ice seals typically either tolerate or
habituate to seismic noise produced from open water sources.
Underwater audiograms have been obtained using behavioral methods
for three species of phocinid seals, ringed, harbor, and harp seals
(Pagophilus groenlandicus). These audiograms were reviewed in
Richardson et al. (1995) and Kastak and Schusterman (1998). Below 30-50
kHz, the hearing threshold of phocinids is essentially flat, down to at
There are few data on hearing sensitivity of phocinid seals below 1
kHz. NMFS considers harbor seals to have a hearing threshold of 70-85
dB at 1 kHz (60 FR 53753, October 17, 1995), and recent measurements
for a harbor seal indicate that, below 1 kHz, its thresholds
and Schusterman, 1998).
While no detailed studies of reactions of seals from open-water
seismic exploration have been published (Richardson et al., 1991,
1995), some data are available on the reactions of seals to various
types of impulsive sounds (see LGL and Greeneridge, 1997, 1998, 1999a;
Thompson et al., 1998). These references indicate that it is unlikely
that pinnipeds would be harassed or injured by low frequency sounds
from a seismic source unless they were within relatively close
proximity of the seismic array. For permanent injury, pinnipeds would
likely need to remain in the high-noise field for extended periods of
time. Existing evidence also suggests that, while seals may be capable
of hearing sounds from seismic arrays, they appear to tolerate intense
pulsatile sounds without known effect once they learn that there is no
danger associated with the noise (see, for example, NMFS/Washington
Department of Wildlife, 1995). In addition, they will apparently not
abandon feeding or breeding areas due to exposure to these noise
sources (Richardson et al., 1991) and may habituate to certain noises
over time.
Proposed Safety Radii
NMFS has determined that for acoustic effects, using established
acoustic thresholds in combination with corresponding safety radii is
the most effective way to consistently both apply measures to avoid or
minimize the impacts of an action and to quantitatively estimate the
effects of an action. NMFS believes that cetaceans and pinnipeds should
not be exposed to pulsed underwater noise at received levels exceeding,
respectively, 180 and 190 dB re 1 microPa (rms) to avoid permanent
physiological damage (Level A Harassment). NMFS also assumes that
cetaceans or pinnipeds exposed to levels exceeding 160 dB re 1 microPa
(rms) experience Level B Harassment. Thresholds are used in two ways:
(1) To establish a mitigation shut-down or power down zone, i.e., if an
animal enters an area calculated to be ensonified above the level of an
established threshold, a sound source is powered down or shut down; and
(2) to calculate take, in that a model may be used to calculate the
area around the sound source that will be ensonified to that level or
above, then, based on the estimated density of animals and the distance
that the sound source moves, NMFS can estimate the number of marine
mammals that may be ``taken''.
In order to implement shut-down zones, or to estimate how many
animals may potentially be exposed to a particular sound level using
the acoustic thresholds described above, it is necessary to understand
how sound will propagate in a particular situation. Models may be used
to estimate at what distance from the sound source the water will be
ensonified to a particular level. Safety radii represent the estimated
distance from the sound source at which the received level of sound
would be 190, 180, and 160 dB.
Conoco's application contains their initial proposed safety radii
and take estimates. However, the initial model Conoco used did not take
into consideration either the physical characteristics of the Chukchi
Sea or the fact that the water was only 50 m deep, and NMFS was
concerned that the proposed radii were too small. Subsequently, Conoco
adopted a new model and submitted new proposed safety and take
estimates. They used an advanced airgun array source model to predict
the 190, 180, and 160 dB isopleths for the proposed seismic survey in
the Chukchi Sea. This model simulates the throttled injection of high-
pressure air from airgun chambers into underwater air bubbles,
simulates the complex oscillation of each bubble, taking into account
the hydrostatic pressure effects of the pressure waves from all other
airguns, and includes effects such as surface-reflected pressure waves,
heat transfer from bubble to the surrounding water, and the buoyancy of
the bubbles. The model also takes into consideration the bathymetry,
water properties, and geoacoustic properties of the sea bed layers in
the proposed survey area. The calculated safety radii from this model
are as follows: the 190-dB radius is 230 m (754 ft), the 180-dB radius
is 850 m (2,788), and the 160-dB radius is 4,590 m (2.85 mi).
Though the model considers some of the site-specific
characteristics of the Chukchi Sea, because no sound propagation
studies have previously been conducted in the proposed survey area
(against which model results can be prepared) NMFS believes that it is
appropriate and necessary to field-verify the modeled safety radii.
Accordingly, field verification will be conducted prior to initiation
of the seismic survey and, until that time, Conoco will multiply the
modeled 190-dB and 180-dB safety radii by 1.5 (which equals 345 m (1121
ft) and 1,275 m (4, 174 ft), respectively) to conservatively establish
the mitigation shutdown zones for marine mammals (see Mitigation
section). The 1.5 correction factor will not be used in the take
estimations.
Field verification will be conducted using an autonomous ocean
bottom hydrophone. This hydrophone is suspended (upward, by float) from
an anchor dropped to the ocean floor, and then released to the surface
for data collection when a particular frequency tone is directed at the
hydrophone. The MV Patriot will run directly, in a straight line, at,
over, and past the hydrophone to establish received sound levels at
distances in front of and behind the sound source. Then, the MV Patriot
will do a lawnmower type zig-zag sideways to the hydrophone so that
received levels at varying distances to the side of the sound source
may be measured. Because of the shape of the array, sound propagates
farther laterally from the source than forward or backward, so both
orientations are measured, then a conservative combination of the two
is used to calculate the safety radii. NMFS will use the field verified
safety radii to establish
[[Page 27691]]
power-down and shut-down zones for the MV Patriot.
Estimated Take by Incidental Harassment for Conoco's Proposed Seismic
Survey
Given the proposed mitigation (see Mitigation later in this
document), all anticipated takes will consist of Level B harassment, at
most. The proposed mitigation measures are expected to minimize or
eliminate the possibility of Level A harassment or mortality.
Additionally, these numbers do not take into consideration either the
effectiveness of the mitigation measures or the fact that some species
will avoid the sound source at distances greater than those estimated
to result in a take.
It is difficult to make accurate, scientifically defensible, and
observationally verifiable estimates of the number of individuals
likely to be subject to Level B Harassment by the noise from Conoco's
airguns. There are many uncertainties in marine mammal and seasonally
varying abundance, in local horizontal and vertical distribution; in
marine mammal reactions to varying frequencies and levels of acoustic
pulses; and in perceived sound levels at different horizontal and
oblique ranges from the source.
NMFS beleieves the best estimate of potential ``take by
harassment'' is derived by multiplying the estimated densities (per
square kilometer) of each species within the proposed survey area by
the width of the 160-dB safety radii (4,590 m (2.85 mi)) over the
length of Conoco's estimated trackline (16,576 km (10,300)). Since
Conoco revised their safety radii after submitting their application,
the estimated take numbers presented here are higher than those
predicted in their application. The total estimated ``take by
harassment'' is presented in Table 1. As mentioned previously, the
upper limit of estimated take for ringed and bearded seals suggested in
Table 1 is most likely an overestimate, as it is based on surveys of
the animals conducted nearer to shore, where densities are higher than
they are off-shore where the seismic surveys will be conducted.
Potential Effects on Habitat
Conoco states that the proposed seismic survey will not cause any
permanent impact on habitats and the prey used by marine mammals. A
broad discussion on the various types of potential effects of exposure
to seismic on fish and invertebrates can be found in LGL (2005;
University of Alaska-Fairbanks Seismic Survey across Arctic Ocean at
http://www.nmfs.noaa.gov/pr/permits/incidental.htm#iha), and includes a
summary of direct mortality (pathological/ physiological) and indirect
(behavioral) effects.
Mortality to fish, fish eggs and larvae from seismic energy sources
would be expected within a few meters (0.5 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 of being 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 are predicted by
Conoco 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. The planned Conoco trackline
is 16,576 km (10,300 ft) long, and will encompass approximately a 2500-
3600 km\2\-area (965-1390 mi\2\-area) in the northeastern Chukchi Sea.
Only a small fraction of the available habitat would be impacted by
noise at any given time during the seismic surveys, and the constant
movement of the seismic vessel would prevent any area from sustaining
high noise levels for extended periods of time. Disturbance to fish
species would most likely be short-term and temporary. Similarly,
concentrations of zooplankton consumed by mysticetes would only respond
to a seismic impulse very close to the source, where they may scatter
before regrouping after the seismic vessel passes. Thus, the proposed
activity is not expected to have any effects on habitat or prey that
could cause permanent or long-term consequences for individual marine
mammals or their populations, since operations will be limited in
duration, location, timing, and intensity.
Potential Effects on Subsistence Use of Marine Mammals
Marine mammals are key in the subsistence economies of the
communities bordering the seismic survey area, including Barrow,
Wainwright, Point Lay, and Point Hope. Other communities that subsist
on marine mammals are considerably beyond the project area, and their
subsistence activities are unlikely to be affected by the seismic
operations in the Chukchi Sea. The whale harvests have a great
influence on social relations by strengthening the sense of Inupiat
culture and heritage in addition to reinforcing family and community
ties.
Bowhead whales are important for subsistence at all of the villages
bordering the project area except Point Lay, which does not hunt
bowhead whales. The harvest is based on a quota, established by the
International Whaling Commission (IWC ) and regulated by agreement
between Alaska Eskimo Whaling Commission (AEWC) and NMFS, according to
the cultural and nutritional needs of Alaska Eskimos as well as on
estimates of the size and growth of the stock of bowhead whales (Suydam
and George 2004). In 2002 the IWC set a 5-year block quota of 67
strikes per year with a total landed not to exceed 280 whales (IWC
2003). The most recent data show that 37, 35, and 36 whales were landed
in 2000-2004 for a total of 108 whales (Suydam and George 2004, Suydam
et al. 2005). Between 23 and 28 were taken at Point Hope, Wainwright,
and Barrow during these years, with most (60-90 percent) taken by
Barrow each year.
Bowheads are hunted during the spring and fall migrations. Point
Hope and Wainwright only hunt during the spring migration whereas
Barrow hunts during the spring and fall migrations. Barrow takes most
bowheads during the spring migration. The spring bowhead hunt occurs
after leads open due to the deterioration of pack ice, which typically
occurs from early April until the first week of June. Because of the
timing, the Spring hunts of Point Hope, Wainwright, and Barrow should
not be affected by seismic operation, since the
[[Page 27692]]
hunt should be completed before the start of seismic operations in
July.
The autumn hunt at Barrow usually begins in mid-September, and
mainly occurs in the waters east and northeast of Point Barrow in the
Beaufort Sea. The whales have usually left the Beaufort Sea by late
October (Treacy 2002a,b). The location of the fall hunt depends on ice
conditions, which can influence distance of whales from shore (Brower,
1996). Hunters prefer to take bowheads close to shore to avoid a long
tow during which the meat can spoil, but Braund and Moorehead (1995)
report that crews may (rarely) pursue whales as far as 80 km, and in
2004 hunters harvested a whale up to 50 km northeast of Barrow (Suydam
et al., 2005). Conoco asserts that though some whales are reported off
Barrow in summer between migrations, subsistence at Barrow should not
be affected by seismic operations since the location of the hunt is a
considerable distance from the project area (Craig George, personal
communications).
Beluga whales are hunted for subsistence at Barrow, Wainwright,
Point Lay, and Point Hope, with the most taken by Point Lay (Fuller and
George 1997). Point Lay harvests belugas primarily during summer in
Kasegaluk Lagoon, where they averaged 40 belugas per year over a 10-
year period (Fuller and George, 1997). Compared to Point Lay, small
numbers of belugas are harvested by Barrow with intermediate numbers
harvested by Point Hope and Wainwright. Harvest at these villages
generally occurs between April and July, with most taken in April and
May when pack-ice conditions deteriorate and leads open up. Hunters
usually wait until after the bowhead whale hunt to hunt belugas. The
Alaska Beluga Whale Committee recorded 23 beluga whales harvested by
Barrow hunters from 1987 to 2002, ranging from 0 in 1987, 1988 and 1995
to the high of 8 in 1997 (Fuller and George, 1999; Alaska Beluga Whale
Committee 2002 in USDI/BLM 2005). The time of the project will not
overlap hunts at Point Hope, Wainwright, and Barrow, and Point Hope and
Barrow should be largely beyond any influence of the project
activities. Point Lay villagers hunt in Kasegaluk Lagoon, which is
beyond the influence of the project activities. Furthermore, the lagoon
is shallow and close to shore, which would greatly reduce any
underwater seismic noise, in the unlikely event noise reached the
lagoon.
Ringed, bearded, and spotted seals are hunted by all of the
villages bordering the project area (Fuller and George 1997). Ringed
seals comprise the largest part of the subsistence hunt and spotted
seal the least, particularly at Barrow where they are primarily hunted
near shore. Spotted seals are considerably more abundant in the Chukchi
than Beaufort Sea. At Barrow, spotted seals are primarily hunted in
Admiralty Bay, which is about 60 km east of Barrow. The largest
concentrations of spotted seals in Alaska are in Kasegaluk Lagoon,
where Point Lay hunters harvest them. (Frost et al. 1993). Braund et
al. (1993) found that the majority of bearded seals taken by Barrow
hunters are within approximately 24 km (15 mi) off shore. Ringed and
bearded seals are hunted throughout the year, but most are taken in
May, June, and July when ice breaks up and there is open water instead
of the more difficult hunting of seals at holes and lairs. The timing
slightly varies among villages, with peak hunting occurring
incrementally later going from Point Hope to Barrow. Spotted seals are
only hunted in spring through summer, since they winter in the Bering
Sea. The seismic operation should have little to no effect on
subsistence hunting since the seismic survey will no more than
minimally overlap the end of the primary period when seals are
harvested, and most hunting at the villages will be a considerable
distance away from seismic operations, particularly at Point Hope (74
km (46 mi)) and Point Lay (90 km (56 mi)).
Natives in Alaska are very concerned about how seismic operations
in the Chukchi Sea will impact their subsistence harvest of marine
mammals. NMFS shares these concerns and some of the studies presented
in the Effects section of this document further validate them. NMFS
notes, though, that some of the types of behaviors that may affect the
subsistence harvest may not be considered MMPA Harassment (such as a
minor migration route deflection ). Following are a few of their
primary concerns:
(1) Native knowledge suggests that sound from seismic surveys may
cause bowhead whales or other subsistence stocks to change their
behavior or migratory patterns in such a way that they are not present
in traditional hunting grounds or in historical numbers. If so, natives
may be unable to harvest any animals, or will have to harvest them from
such a distance that the animal may spoil during the long tow back and
human safety risks are increased during the extended trip.
(2) Native knowledge indicates that bowhead whales become
increasingly ``skittish'' in the presence of seismic noise. Whales are
more wary around the hunters and tend to expose a much smaller portion
of their back when surfacing (which makes harvesting more difficult).
Additionally, natives report that bowheads exhibit angry behaviors in
the presence of seismic, such as tail-slapping, which translate to
danger for nearby subsistence harvesters.
(3) Natives are concerned that the cumulative effects of increased
numbers of concurrent seismic surveys in the Chukchi and Beaufort Seas
may have population-level effects on subsistence stocks that will
permanently affect their subsistence harvest. An additional concern is
the perception of the increased risk of population-level effects by the
IWC, which could decide to lower the subsistence quotas for Alaska or
reduce them to zero.
Plan of Cooperation
Regulations at 50 CFR 216.104(a)(12)(i) require IHA applicants for
activities that take place in Arctic waters to provide a plan of
cooperation (POC) or information that identifies what measures have
been taken and/or will be taken to minimize any adverse effects on the
availability of marine mammals for subsistence purposes.
Representatives of Conoco have been in continued coordination with the
AEWC and met with the whaling captains of the potentialy affected
villages in March, 2006. Additionally, both Conoco and the AEWC had
representatives present at the Open-Water Seismic meeting held in
Alaska in April and further negotiated appropriate measures to minimize
impacts to the subsistence harvest. Conoco is currently working on a
Conflict Avoidance Agreement (CAA) with the AEWC.
Conoco anticipates signing the CAA sometime this spring. The CAA
will incorporate all appropriate measures and procedures regarding the
timing and areas of the operator's planned activities (i.e., times and
places where seismic operations will be curtailed or moved in order to
avoid potential conflicts with active subsistence whaling and sealing);
communications system between operators vessels and whaling and hunting
crews; provision for marine mammal observers/Inupiat communicators
aboard all project vessels; conflict resolution procedures; and
provisions for rendering emergency assistance to subsistence hunting
crews.
Based on our understanding of what the finalized CAA will contain,
as well as some additional mitigation and monitoring measures discussed
later in this document (see Mitigation), NMFS has preliminarily
determined that the proposed activity will not have an unmitigable
adverse impact on the
[[Page 27693]]
subsistence harvest of the affected species or stocks.
Mitigation and Monitoring
Three categories of mitigation and monitoring measures are
discussed in the following section. In the first subsection, the
mitigation and monitoring measures proposed by Conoco in their
application are discussed. In the second subsection an additional
comprehensive monitoring plan, which Conoco has agreed to in concept,
but not in every detail, is discussed. The third subsection refers to
an additional set of mitigation measures that are intended to ensure
that NMFS' can adopt MMS' PEA to meet our NEPA responsibility for the
issuance of an IHA to Conoco, and subsequently issue a Finding of No
Significant Impact.
Mitigation and Monitoring Measures Proposed in Conoco's Application
Mitigation
Conoco's application indicates that both a 16-gun array and,
occasionally, a 24-gun array will be used to acquire data during the
proposed seismic survey. However, subsequent to discussions at the
Alaska Open-Water Seismic meeting of how to reduce effects to marine
mammals, Conoco has redesigned their survey plan to use only the 16-
array gun.
Conoco's proposed mitigation measures include (1) speed or course
alteration, provided that doing so will not compromise operational
safety requirements, (2) power-or shutdown procedures, and (3) no start
up of airgun operations unless the full 180 dB safety zone is visible
for at least 30 minutes during day or night. Details regarding these
measures are provided below:
Speed or Course Alteration: If a marine mammal is detected outside
the safety radius and, based on its position and the relative motion,
is likely to enter the safety radius, the vessel's speed and/or direct
course may, when practical and safe, be changed in a way that avoids
the marine mammal and also minimizes the effect on the seismic program.
The marine mammal activities and movements relative to the seismic
vessel will be closely monitored to ensure that the marine mammal does
not approach within the safety radius. If the mammal appears likely to
enter the safety radius, further mitigative actions will be taken,
i.e., either further course alterations or power down or shut down of
the airgun(s).
Power-down Procedures: A power down involves decreasing the number
of airguns in use such that the radius of the 180-dB (or 190-dB) zone
is decreased to the extent that marine mammals are not in the safety
zone. A power down may also occur when the vessel is moving from one
seismic line to another. During a power down, one airgun is operated.
The continued operation of one airgun is intended to alert marine
mammals to the presence of the seismic vessel in the area. In contrast,
a shut down occurs when all airgun activity is suspended. If a marine
mammal is detected outside the safety radius but is likely to enter the
safety radius, and if the vessel's speed and/or course cannot be
changed to avoid having the mammal enter the safety radius, the airguns
may (as an alternative to a complete shut down) be powered down before
the mammal is within the safety radius. Likewise, if a mammal is
already within the safety zone when first detected, the airguns will be
powered down if doing so leaves the animals outside of the new safety
radii around the airguns still operating, else they will be shut down.
Following a power down, airgun activity will not resume until the
marine mammal has cleared the safety zone. The animal will be
considered to have cleared the safety zone if it:
Is visually observed by marine mammal observers (MMOs) to
have left the safety zone, or
Has not been seen within the zone for 15 min in the case
of pinnipeds or belugas, or
Has not been seen within the zone for 30 min in the case
of bowhead, gray, or killer whales.
Shut-down Procedures: The operating airgun(s) will be shut down
completely if a marine mammal approaches or enters the safety radius
and a power down will not succeed in removing the animal from within
the 180 dB isopleth. The operating airgun(s) will also be shut down
completely if a marine mammal approaches or enters the estimated safety
radius of the source that would be used during a power down. The
shutdown procedure should be accomplished within several seconds (of a
``one shot'' period) of the determination that a marine mammal is
within or about to enter the safety zone. Airgun activity will not
resume until the marine mammal has cleared the safety radius. The
animal will be considered to have cleared the safety radius if it is
visually observed to have left the safety radius, or if it has not been
seen within the radius for 15 minutes (beluga and seals) or 30 minutes
(bowhead, gray, and killer whales).
Ramp-up Procedures: A ``ramp up'' procedure will be followed when
the airgun array begins operating after a specified-duration period
without airgun operations. Under normal operation conditions (4-5 knots
(7.4-9.2 km/hr)) a ramp-up would be required after a ``no shooting''
period lasting 2 minutes or longer. NMFS normally requires that the
rate of ramp up be no more than 6 dB per 5 minute period. The specified
period depends on the speed of the source vessel and the size of the
airgun array that is being used. Ramp up will begin with the smallest
gun in the array that is being used for all subsets of the array. Guns
will be added in a sequence such that the source level in the array
will increase at a rate no greater than 6 dB per 5-minutes, which is
the normal rate of ramp up for larger airgun arrays. During the ramp up
(i.e., when only one airgun is operating), the safety zone for the full
16-airgun system will be maintained.
If the complete safety radius has not been visible for at least 30
minutes prior to the start of operations in daylight or nighttime,
ramp-up will not commence unless one gun has been operating during the
interruption of seismic survey operations. This means that it will not
be permissible to ramp up the source from a complete shut down in thick
fog or at other times when the full safety zone is not visible (i.e.,
sometimes at night). If the entire safety radius is visible using
vessel lights and/or Night Vision Devices (NVDs) (as may be possible
under moonlit and calm conditions), then start up of the airguns from a
shut down may occur at night. If one airgun has operated during a
power-down period, ramp up to full power will be permissible at night
or in poor visibility, on the assumption that marine mammals will be
alerted to the approaching seismic vessel by the sounds from the single
airgun and could move away if they choose. Ramp-up of the airguns will
not be initiated if a marine mammal is sighted within or near the
applicable safety radii during the day or a night. For operations in
the Chukchi during summer and autumn months, there will be enough
daylight to monitor beyond a 12-hour cycle.
Monitoring
Vessel-based observers will monitor marine mammals near the seismic
vessel during: (1) all daytime hours; (2) 30 minutes before all start
ups (day or night), and (3) at night when marine mammals are suspected
(based on observations of the bridge crew) of either approaching or
being within the safety radii. When feasible, observations will also be
made during daytime periods during transits and other operations when
guns are inactive.
During seismic operations observers will be based aboard the
vessel. Marine
[[Page 27694]]
mammal observers (MMOs) will be hired by Conoco, with NMFS approval.
One resident from the North Slope Borough, preferably from Point Hope,
Point Lay, Wainwright, or Barrow, who is knowledgeable about marine
mammals of the project area will to be included in the MMO team aboard
the vessel. Observers will follow a schedule so at least two observers
will simultaneously monitor marine mammals near the seismic vessel
during ongoing daytime operations and nighttime start ups of the
airgun. Use of two simultaneous observers will increase the proportion
of the animals present detected near the source vessel. MMO(s) will
normally be on duty in shifts no longer than 4 hours. The vessel crew
will also be instructed to assist in detecting marine mammals and
implementing mitigation requirements (if practical). Before the start
of the seismic survey the crew will be given additional instruction on
how to do so.
The vessel is a suitable platform for marine mammal observations.
When stationed on the flying bridge, the eye level will be
approximately 10 m (32.8 ft) above sea level, and the observer will
have an unobstructed view around the entire vessel. If surveying from
the bridge, the observer's eye level will be about 10 m (32.8 ft) above
sea level and approx. 25[deg] of the view will be partially obstructed
directly to the stern by the stack. During daytime, the MMO(s) will
scan the area around the vessel systematically with reticle binoculars
(e.g., 7 50 Bushnell or equivalent) and with the naked eye. Laser range
finders (Leica LRF 1200 laser rangefinder or equivalent) will be
available to assist with distance estimation. They are useful in
training observers to estimate distances visually, but are generally
not useful in measuring distances to animals directly. During darkness,
NVDswill be available (ITT F500 Series Generation 3 binocular-image
intensifier or equivalent), if and when required.
MMOs will collect the following data during their watch:
(1) Marine mammals - species, number, age/size/gender, behavior,
movement, distance and bearing from ship, point of closest approach;
(2) Ship - location, heading, speed, seismic state, time, other
ships; and
(3) Environment - sea state, ice cover, visibility, glare.
When mammals are detected within or about to enter the designated
safety radius, the airgun(s) will be powered down (or shut down if
necessary) immediately. The observer(s) will continue to maintain watch
to determine when the animal(s) are outside the safety radius. Airgun
operations will not resume until the animal is outside the safety
radius. The animal will be considered to have cleared the safety radius
if it is visually observed to have left the safety radius, or if it has
not been seen within the radius for 15 minutes (beluga whales and
seals) or 30 minutes (gray, bowhead, and killer whales).
All observations and airgun shut downs will be recorded in a
standardized format. Data will be entered into a custom database using
a notebook computer. The accuracy of the data entry will be verified by
computerized validity data checks as the data are entered and by
subsequent manual checking of the database. These procedures will allow
initial summaries of data to be prepared during and shortly after the
field program, and will facilitate transfer of the data to statistical,
graphical, or other programs for further processing and archiving.
Results from the vessel-based observations will provide:
(1) The basis for real-time mitigation (airgun shut-down and power-
down)
(2) Information needed to estimate the number of marine mammals
potentially taken by harassment, which must be reported to NMFS
(3) Data on the occurrence, distribution, and activities of marine
mammals in the area where the seismic study is conducted.
(4) Information to compare the distance and distribution of marine
mammals relative to the source vessel at times with and without seismic
activity.
(5) Data on the behavior and movement patterns of marine mammals
seen at times with and without seismic activity.
Reporting
A report will be submitted to NMFS within 90 days after the end of
the project. The report will describe the operations that were
conducted and the marine mammals that were detected near the
operations. The report will be submitted to NMFS, providing full
documentation of methods, results, and interpretation pertaining to all
monitoring. The 90-day report will summarize the dates and locations of
seismic operations, and all marine mammal sightings (dates, times,
locations, activities, associated seismic survey activities), ship
data, and environmental data. The report will also include estimates of
the amount and nature of potential exposure of marine mammals to
seismic sound levels above the Level B Harassment threshold.
Additional Comprehensive Monitoring Plan
On April 19-20, 2006, NMFS held a scientific peer-review meeting in
Anchorage, AK to discuss appropriate mitigation and monitoring measures
for Arctic Ocean seismic activities in 2006. The workshop participants
recommended several monitoring measures to increase our knowledge of
marine mammal distribution and abundance in the Chukchi Sea. These
included use of passive acoustics, either towed from a vessel or set
out in a series of arrays along the Chukchi Sea coast. As of the
publication date of this notice, Conoco is studying these
recommendations and will inform NMFS prior to the close of the comment
period on this document.
Additional Mitigation and Monitoring Measures Required by NMFS
The 2006 MMS PEA, which is still open for public comment, contains
multiple alternatives with several different mitigation and monitoring
measures beyond those proposed by Conoco in their IHA application, such
as more effective monitoring methods and expanded power-down and shut-
down zones for bowhead and gray whales during certain periods of time.
NMFS' final IHA may include some portion and combination of those
additional mitigation and monitoring measures.
Endangered Species Act
Under section 7 of the ESA, the MMS has begun consultation on the
proposed seismic survey activities in the Beaufort and Chukchi seas
during 2006. NMFS will also consult on the issuance of the IHA under
section 101(a)(5)(D) of the MMPA to Conoco for this activity.
Consultation will be concluded prior to a determination on the issuance
of an IHA.
National Environmental Policy Act (NEPA)
The MMS has prepared a Draft PEA for the 2006 Arctic Outer
Continental Shelf (OCS) Seismic Surveys. NMFS is a cooperating agency
in the preparation of the Draft PEA. NMFS is reviewing this PEA and
will either adopt it or prepare its own NEPA document before making a
determination on the issuance of Arctic Ocean OCS seismic surveys in
2006. A copy of the MMS Draft PEA for this activity is available upon
request and is available online (see ADDRESSES).
[[Page 27695]]
Preliminary Conclusions
Summary
Based on the information provided in Conoco's application and the
MMS PEA, NMFS has preliminarily determined that the impact of Conoco
conducting seismic surveys in the northeastern Chukchi Sea in 2006 will
have a negligible impact on marine mammals and that there will not be
any unmitigable adverse impacts to subsistence communities, provided
the mitigation measures required under the authorization are
implemented and a CAA is implemented.
Potential Impacts on Marine Mammals
NMFS has preliminarily determined that the relatively short-term
impact of conducting seismic surveys in the U.S. Chukchi Sea may
result, at worst, in a temporary modification in behavior by certain
species of marine mammals and/or low-level physiological effects (Level
B Harassment). 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 affected species
and stocks of marine mammals.
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 relatively small in light of the population size (see
Table 1).
In addition, no take by death and/or serious injury is anticipated,
and the potential for temporary or permanent hearing impairment will be
avoided through the incorporation of the proposed mitigation measures
described in this document. This preliminary determination is supported
by (1) the likelihood that, given sufficient notice through slow ship
speed and ramp-up of the seismic array, marine mammals are expected to
move away from a noise source that it is annoying prior to its becoming
potentially injurious; (2) recent research that indicates that TTS is
unlikely (at least in delphinids) until levels closer to 200-205 dB re
1 microPa are reached rather than 180 dB re 1 microPa; (3) the fact
that the 200-205 dB isopleth (see number 2 above) would be very close
to the vessel; and (4) the likelihood that marine mammal detection
ability by trained observers is close to 100 percent during daytime and
remains high at night out to the distance from the seismic vessel that
corresponds to the 205 dB isopleth.
Finally, no known rookeries, mating grounds, areas of concentrated
feeding, or other areas of special significance for marine mammals are
known to occur within or near the planned areas of operations during
the season of operations.
Potential Impacts on Subsistence Uses of Marine Mammals
Preliminarily, NMFS believes that the proposed seismic activity by
Conoco in the northern Chukchi Sea in 2006, in combination with other
seismic and oil and gas programs in these areas, 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 following: (1) Seismic activities in the Chukchi Sea will not
begin until after July 10 by which time the spring bowhead hunt is
expected to have ended; (2) the fall bowhead whale hunt in the Beaufort
Sea will be governed by a CAA between Conoco and the AEWC and village
whaling captains, which includes conditions that will significantly
reduce impacts on subsistence hunters; (4) while it is possible, but
unlikely, that accessibility to belugas during the spring subsistence
beluga hunt could be impaired by the survey, very little of the
proposed survey is within 25 km (15.5 mi) of the Chukchi coast, meaning
the vessel will usually be well offshore 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, it should not conflict with harvest activities.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to Conoco for conducting a seismic survey in the northern
Chukchi Sea in 2006, provided the previously mentioned mitigation,
monitoring, and reporting requirements are incorporated.
Dated: May 8, 2006.
Donna Wieting,
Deputy Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 06-4434 Filed 5-9-06; 1:01 pm]
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