Small Takes of Marine Mammals Incidental to Open-water Seismic Operations in the Chukchi Sea, 27685-27695 [06-4434]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 71, Number 92 (Friday, May 12, 2006)]
[Notices]
[Pages 27685-27695]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 06-4434]


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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: https://
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 
operates at 200 kHz, the maximum output is 185 dB re 1 microPa @ 1m, 
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, 
the maximum output is 183 dB re 1 microPa @ 1m, and the beam is 
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: https://
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: 
(https://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
--------------------------------------------------------------------------------------------------------------------------------------------------------

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 
least 1 kHz, and ranges between 60 and 85 dB (re 1 microPa @ 1 m). 
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 
deteriorate gradually to 97 dB (re 1 microPa @ 1 m) at 100 Hz (Kastak 
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 
https://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 o