[Federal Register Volume 66, Number 115 (Thursday, June 14, 2001)]
[Notices]
[Pages 32321-32328]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-15060]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[I.D. 052401B]


Small Takes of Marine Mammals Incidental to Specified Activities; 
Offshore Seismic Activities in the Beaufort Sea

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: ACTION: Notice of receipt of application and proposed 
authorization for a small take exemption; request for comments.

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SUMMARY: NMFS has received a request from WesternGeco, LLC (formerly 
Western Geophysical) for an authorization to take small numbers of 
marine mammals by harassment incidental to conducting ocean bottom 
cable (OBC) seismic surveys in the Alaskan Beaufort Sea. Under the 
Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its 
proposal to authorize WesternGeco to incidentally take, by harassment, 
small numbers of bowhead whales and other marine mammals in the above 
mentioned area during the open water period of 2001.

DATES: Comments and information must be received no later than July 16, 
2001.

ADDRESSES: Comments on the application should be addressed to Donna 
Wieting, Chief, Marine Mammal Conservation Division, Office of 
Protected Resources, NMFS, 1315 East-West Highway, Silver Spring, MD 
20910-3225. A copy of the application, the Technical Monitoring Plan, 
the Environmental Assessment (EA), and a list of references used in 
this document may be obtained by writing to this address or by 
telephoning one of the contacts listed here.

FOR FURTHER INFORMATION CONTACT: Simona Perry Roberts, Office of 
Protected Resources (301) 713-2322, ext. 106, or Brad Smith, Alaska 
Region (907) 271-5006.

SUPPLEMENTARY INFORMATION:

Background

    Sections 101 (a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce to allow, upon request, the 
incidental, but not intentional taking of small numbers of marine 
mammals by U.S. citizens who engage in a specified activity (other than 
commercial fishing) within a specified geographical region if certain 
findings are made and either regulations are issued or, if the taking 
is limited to harassment, notice of a proposed authorization is 
provided to the public for review.
    Permission may be granted if NMFS finds that the taking will have 
no more than a negligible impact on the species or stock(s) and will 
not have an unmitigable adverse impact on the availability of the 
species or stock(s) for subsistence uses and that the permissible 
methods of taking and requirements pertaining to the monitoring and 
reporting of such taking are set forth.
    On April 10, 1996 (61 FR 15884), NMFS published an interim rule 
establishing, among other things, procedures for issuing incidental 
harassment authorizations (IHAs) under section 101 (a)(5)(D) of the 
MMPA for activities in Arctic waters. For additional information on the 
procedures to be followed for this authorization, please refer to that 
document.

Summary of Request

    On April 16, 2001, NMFS received an application from WesternGeco 
requesting an authorization for the harassment of small numbers of 
several species of marine mammals incidental to conducting OBC seismic 
surveys during the open water season in the south central Beaufort Sea 
off Alaska between western Camden Bay and Harrison Bay. The primary 
area of seismic activity is expected to be an area approximately 16 by 
7 kilometers (km) (10 miles (mi) by 4 mi) in and near Simpson Lagoon, 
west of Prudhoe Bay and offshore of Oliktok Point. Weather permitting, 
the survey is expected to take place between approximately July 15 and 
late October, 2001. WesternGeco anticipates completing six survey 
patches during the 2001 open water season. A detailed description of 
the work proposed for 2001 is contained in the application 
(WesternGeco, 2001) which is available upon request (see ADDRESSES).

Description of the Activity

    Seismic surveys are used to obtain data about geological formations 
several thousands of feet deep. The proposed seismic operation is an 
OBC survey. WesternGeco's OBC survey involves dropping cables from a 
ship to the ocean bottom, forming a patch consisting of 4 parallel 
cables 8.9 km (5.5 mi) long, separated by approximately 600 meters (m) 
(1,968 feet (ft)) from each other. Hydrophones and geophones, attached 
to the cables, are used to detect seismic energy reflected back from 
rock strata below the ocean bottom. The source of this energy is a 
submerged acoustic source, called a seismic airgun array, that releases 
compressed air into the water, creating an acoustical energy pulse that 
is directed downward toward the seabed. WesternGeco will use two source 
vessels for the open-water 2001 seismic surveys, one for deep water and 
one for shallow water, primarily shoreward of the barrier islands. The 
deep water vessel, the R/V Arctic Star, will utilize an airgun array 
with an air discharge volume of 1,210 cubic inches

[[Page 32322]]

(in\3\) (19.8 liters, L). The maximum source levels for the Arctic Star 
will be at 249 dB re 1 micro Pascal per minute (Pa-m) (when the 
acoustic pressure is 29.4 bar-meters (zero to peak)), or 253 dB re 1 
micro Pa-m (when the acoustic pressure is 45.9 bar-meters (peak-to-
peak)). Most operations utilizing the 1,210 in\3\ array are expected to 
operate at a gun depth of 2.3 m (7.5 ft) and water depth of 10 m (32.8 
ft). The shallow water source vessel, the R/V Peregrine, will utilize 
an airgun array with an air discharge volume of 640 in\3\ (10.48 L). 
The source level maximums for the Peregrine will be at 237 dB re 1 
micro Pa-m (when the acoustic pressure is 6.7 bar-meters (zero to 
peak)), or 242 dB re 1 micro Pa-m (when the acoustic pressure is 12.2 
bar-meters (peak to peak)). These airgun arrays are smaller and less 
powerful than the arrays used in some other seismic programs in the 
Beaufort Sea prior to 1999 and are expected to operate at a gun depth 
of 1 m (3.3 ft) in very shallow water.
    The seismic vessels will sail along pre-plotted source lines 
arranged orthogonally to the OBCs. Each source line will be 5 km (3.1 
mi) long and adjacent source lines will be approximately 500 m (1,640 
ft) apart. There will be 34 source lines for each seismic patch. The 
overall grid of source lines for a given patch will be 4.7 km by 16.5 
km (2.9 mi by 10.2 mi) and the source line for one patch will overlap 
with those from adjacent patches.
    After sufficient data have been recorded to allow accurate mapping 
of the rock strata, the cables are lifted onto the deck of one of the 
two self-powered cable vessels (R/V Western Endeavor and R/V Western 
Frontier), moved to a new location (ranging from several hundred to a 
few thousand feet away), and placed onto the seabed again. A small 
utility vessel (Ski Barge) may also be used to transfer seismic crew 
and/or marine mammal observers, as well as supplies and refuse, between 
the seismic vessels and Prudhoe Bay. Air support will be limited to 
infrequent (if any) helicopter flights and, starting in early 
September, aerial surveys at altitudes from 900 to 1500 ft (274 to 457 
m). For a more detailed description of the seismic operation, please 
refer to WesternGeco (2001).

Description of Habitat and Marine Mammals Affected by the Activity

    A detailed description of the Beaufort Sea ecosystem and its 
associated marine mammals can be found in several documents (Corps of 
Engineers, 1999; NMFS, 1999; Minerals Management Service (MMS), 1992, 
1996) and is not repeated here.

Marine Mammals

    The Beaufort/Chukchi Seas support a diverse assemblage of marine 
mammals, including bowhead whales (Balaena mysticetus), gray whales 
(Eschrichtius robustus), beluga whales(Delphinapterus leucas), ringed 
seals (Phoca hispida), spotted seals (Phoca largha) and bearded seals 
(Erignathus barbatus). Descriptions of the biology and distribution of 
these species and of others can be found in NMFS (1999), Western 
Geophysical (2000), WesternGeco (2001), the annual monitoring reports 
for seismic surveys in the Beaufort Sea (LGL Ltd. and Greeneridge 
Sciences Inc, 1997, 1998, 1999, 2000) and several other documents 
(Corps of Engineers, 1999; Lentfer, 1988; MMS, 1992, 1996; Ferrero et 
al., 2000). Please refer to those documents for information on these 
species.

Potential Effects of Seismic Surveys on Marine Mammals

    Disturbance by seismic noise is the principal means of taking by 
this activity. Support vessels and aircraft may provide a potential 
secondary source of noise. The physical presence of vessels and 
aircraft could also lead to non-acoustic effects on marine mammals 
involving visual or other cues.
    Underwater pulsed sounds generated by open water seismic operations 
may be detectable a substantial distance away from the activity. The 
effect of these pulsed sounds on living marine resources, particularly 
marine mammals in the area, will be dependent on the hearing 
sensitivity of the species, the behavior of the animal at the time the 
sound is detected, as well as the distance and level of the sound 
relative to ambient conditions. Any sound that is detectable is (at 
least in theory) capable of eliciting a disturbance or avoidance 
reaction by some marine mammals or of masking signals of comparable 
frequency that are generated by marine mammals (e.g., whale calls) 
(WesternGeco, 2001). An incidental harassment take is presumed to occur 
when marine mammals in the vicinity of the seismic source, the seismic 
vessel, other vessels, or aircraft show a disturbance or avoidance 
reaction to the generated sounds or to visual cues.
    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, locations, and seasons. 
Behavioral changes may be subtle alterations in the 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, are less likely than resting animals 
to show overt behavioral reactions, unless the disturbance is directly 
threatening. Seismic pulses have been observed to cause strong 
avoidance reactions by many of the bowhead whales occurring within a 
distance of several kilometers, including changes in surfacing, 
respiration and dive cycles, and to sometimes cause avoidance or other 
changes in bowhead behavior at considerably greater distances 
(Richardson et al., 1995; Rexford, 1996; MMS, 1997; Miller et al., 
1999). Airgun pulses may also disturb some other marine mammal species 
occurring in the area. Ringed seals within a few hundred meters of an 
airgun array showed variable behavior to the noise, with some moving 
somewhat farther away and other seals not moving far at all (Harris et 
al., 1997, 1998, in press; Lawson and Moulton, 1999; Moulton and 
Lawson, 2000).
    Although some masking of low-frequency sounds (e.g., bowhead and 
gray whale calls) is a possibility for this activity, the intermittent 
nature of seismic survey pulses used by WesternGeco (1 second in 
duration every 16 to 24 seconds), as well as the fact that airgun 
operations are expected to occur no more than 50 percent of the time, 
will limit the extent of any 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., 1997, 1999; 
Richardson et al., 1986). Masking effects are expected to be absent in 
the case of beluga whales, given that sounds utilized by them are at 
much higher frequencies (in the 2 to 6 kilohertz (kHz) range) (Sjare 
and Smith, 1986) than are airgun sounds from WesternGeco's seismic 
surveys (highest frequency of 188 hertz(Hz)) (WesternGeco, 2001).
    Permanent hearing damage is not expected to occur during the 
project. There is no direct evidence that the hearing systems of marine 
mammals close to an airgun array would be at risk of temporary or 
permanent hearing impairment; however, depending on the species, the 
equipment being used, and the number of pulses to which the animal is 
exposed, temporary threshold shift (TTS) is a theoretical possibility 
for

[[Page 32323]]

animals within a few hundred meters of the source (Richardson et al., 
1995; Finneran et al.,2000). Planned monitoring and mitigation 
measures, proposed by WesternGeco and 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.

Bowhead Whales

    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 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 bowhead whales 6 km to at least 73 km (3.7 to 45.3 mi) from 
seismic vessels. One visibly apparent avoidance response reported from 
pre-1996 studies involved observations of bowhead whales swimming away 
from a seismic vessel 24 km (15 mi) away (Koski and Johnson, 1987). It 
is likely that some migrating bowhead whales show avoidance at 
distances exceeding those at which Ljungblad et al.(1988) and 
Richardson et al. (1986) observed responses. However, at distances 
greater than around 24 km (15 mi), only subtle changes in the 
surfacing, respiration, dive cycles were detectable (Richardson et al., 
1986).
    Results from the 1996-1998 BP, Inc. and Western Geophysical seismic 
monitoring program indicate that most migrating bowhead whales 
deflected seaward to avoid an area within about 20 km (12.4 mi) of an 
active nearshore seismic operation when there were no barrier islands 
or very shallow water between the seismic operation and the whales 
(Miller et al., 1998, 1999). The available data do not provide an 
unequivocal estimate of the distance at which approaching bowhead 
whales began 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 persisted (Miller et al., 1999). 
Although very few bowhead whales approached within 20 km (12.4 mi) of 
the operating seismic vessel, the number of bowhead whales 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 bowhead whales are sometimes 
displaced at distances considerably greater than suggested by the pre-
1996 scientific studies (Rexford, 1996). Also, whalers believe that 
avoidance effects can extend out to distances on the order of 30 miles, 
and that bowhead whales exposed to seismic pulses are also skittish and 
difficult to approach. The ``skittish'' behavior may be related to the 
observed subtle changes in the behavior of bowhead whales 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 bowhead whales 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 micro-Pa). By some behavioral 
measures, clear effects were evident at average pulse levels of 160+ 
dB, and less consistent results were suspected at levels of 140-160 dB, 
farther away. 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)) of the migration 
corridor, the avoidance response was not evident on track plots (Tyack 
and Clark, 1998).

Beluga Whale

    The beluga whale is the only species of toothed whale (Odontoceti) 
expected to be encountered in the Beaufort Sea. Beluga whales 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 
micro-Pa 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 may sometimes 
be audible to beluga whales 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 
(WesternGeco, 2001). The reaction distance for beluga whales, although 
presently unknown, is expected to be less than that for bowhead whales, 
given the presumed poorer sensitivity of beluga whales to low-frequency 
sounds (WesternGeco, 2001).

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). 
Also, the results from the 1996-2000 BP and Western Geophysical 
monitoring studies provide a substantial amount of directly relevant 
information (Harris et al., 1997, 1998, in press; Lawson and Moulton, 
1999; Moulton and Lawson, 2000). During these monitoring studies, the 
operation of the airgun array had minor and variable effects on the 
behavior of seals within a few hundred meters of the array and (to a 
limited extent) the distribution of seals around the source vessel 
(Moulton and Lawson, 2000). Nonetheless, seals were observed throughout 
each season in the general area where seismic operations were 
occurring. Seals were sometimes observed within the 190 dB re 1 micro-
Pa designated safety radii, and at these times the airguns were shut 
down.
    Underwater audiograms have been obtained for three species of 
phocinid seals - the 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 micro-Pa. There are few published data 
on hearing sensitivity of phocid 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 micro-Pa at 100 Hz (Kastak and Schusterman, 1998).
    Based on published references (see LGL and Greeneridge, 1997, 1998, 
1999a; Thompson et al. 1998), it is unlikely that pinnipeds would be 
harassed or injured by low frequency sounds from a seismic source 
unless

[[Page 32324]]

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. Since seismic 
work is fairly common in Beaufort Sea waters, pinnipeds have been 
previously exposed to seismic noise and may not react to it after 
initial exposure.
    For a discussion on the anticipated effects of ships, boats, and 
aircraft on marine mammals and their food sources, please refer to the 
application (WesternGeco, 2001). Information on these effects is 
preliminarily adopted by NMFS as the best information available on this 
subject.

Numbers of Marine Mammals Expected to Be Taken

    WesternGeco estimates that the following numbers of marine mammals 
may be subject to Level B harassment, as defined in 50 CFR 216.3:

----------------------------------------------------------------------------------------------------------------
                                                                                 Takes by Harassment in 2001
                        Species                           Population Size  -------------------------------------
                                                                            Maximum Number\1\     Probable\2\
----------------------------------------------------------------------------------------------------------------
Bowhead whale                                                        8,200
160 dB criterion                                                         -              1,000                500
20 km criterion                                                          -              2,630              1,300
Gray whale                                                          26,000                 10                  0
Beluga whale                                                        39,258                250                150
Ringed seal\3\                                               1-1.5 million                400                200
Spotted seal\3\                                                   >200,000                 10                  2
Bearded seal\3\                                                   >300,000                 50                 15
----------------------------------------------------------------------------------------------------------------
\1\ The maximum number that might be taken if seismic surveys are operable during the September/October period
  and the bowhead migration passes unusually close to shore as in 1997.
\2\ The number that could be taken under the most likely operating conditions.
\3\ Some individual seals may be harassed more than once.

Estimates of Marine Mammal Takes

    Estimates of takes by harassment will be made through vessel and/or 
aerial surveys. Preliminarily, WesternGeco will estimate the number of 
(1) marine mammals observed within the area strongly ensonified by the 
OBC seismic vessel (see Mitigation section below for area description); 
(2) marine mammals observed showing apparent avoidance or disturbance 
reactions to seismic pulses (e.g., heading away from the seismic vessel 
in an atypical direction); (3) marine mammals estimated to be subject 
to take by type (1) or (2) when no monitoring observations were 
possible; and (4) bowhead whales whose migration routes came within 20 
km or greater (actual distance dependent on a combination of 1996-1998 
and 2001 data) of the operating OBC seismic vessel, or would have if 
they had not been displaced farther offshore.

Effects of Seismic Noise and Other Activities on Subsistence Needs

    The disturbance and potential displacement of marine mammals by 
sounds from seismic activities are the principle concerns related to 
subsistence use of the area. The harvest of marine mammals (mainly 
bowhead whales, but also ringed and bearded seals) is central to the 
culture and subsistence economies of the coastal North Slope 
communities. In particular, if migrating bowhead whales are displaced 
farther offshore by elevated noise levels, the harvest of these whales 
could be more difficult and dangerous for hunters. The harvest could 
also be affected if bowhead whales become more ``skittish'' when 
exposed to seismic noise.
    Nuiqsut is the community closest to the area of the proposed 
activity. The communities of Barrow and Kaktovik also harvest resources 
that pass through the general area, but do not regularly hunt in the 
planned seismic exploration area. Subsistence hunters from all three 
communities conduct an annual hunt for migrating bowhead whales during 
the autumn months. In recent years, Nuiqsut whalers typically take two 
to four whales each year (WesternGeco, 2001). Nuiqsut whalers 
concentrate their efforts on areas north and east of Cross Island, 
generally in water depths greater than 20 m (65 ft).
    Whalers from the village of Kaktovik search for whales east, north, 
and west of the village. Kaktovik is located 72 km (45 mi) east of the 
easternmost end of WesternGeco's planned 2001 seismic exploration area.
    Whalers from the village of Barrow search for bowhead whales much 
farther from the planned seismic area, > 200 km (>125 mi) to the west 
(WesternGeco, 2001).
    The location of the proposed seismic activity is south of the 
center of the westward migration route of bowhead whales, but there is 
some limited overlap with the southern limit of the migration. Seismic 
monitoring results from 1996-1998 indicate that most bowhead whales 
avoid the area within about 20 km (12.4 mi) around the airgun array 
when it is operating, and some avoid the area within 30 km (18.6 mi). 
In addition, bowhead whales may be able to hear the sounds emitted by 
the seismic array out to a distance of 50 km (31.1 mi) or more, 
depending on the ambient noise level and the efficiency of sound 
propagation along the path between the seismic vessel and the whale 
(Miller et al., 1997).
    Cross Island, the principle field camp location for Nuiqsut 
whalers, is located within the general area of the proposed 2001 
seismic area. Thus, the possibility and timing of potential seismic 
operations in the Cross Island area requires WesternGeco to provide 
NMFS with either (1) a Plan of Cooperation with the Alaska Eskimo 
Whaling Commission (AEWC) and the North Slope whaling communities, or 
(2) measures that have been or will be taken to avoid any unmitigable 
adverse impact on the availability of these animals for subsistence 
needs. WesternGeco's application has preliminarily identified those 
measures that will be taken to minimize any adverse effect on 
subsistence. In addition, the timing of seismic operations will be 
addressed in a Conflict Avoidance Agreement (CAA)

[[Page 32325]]

 with the Nuiqsut whalers and the AEWC (WesternGeco, 2001). Also, the 
monitoring plan proposed by WesternGeco (2001) is expected to provide 
information that will help resolve uncertainties about the effects of 
seismic exploration on the accessibility of bowhead whales to hunters.
    Nuiqsut hunters also hunt seals for subsistence purposes. Most seal 
hunting has been during the early summer in open water. Boat crews hunt 
ringed, spotted, and bearded seals. The most important sealing area for 
Nuiqsut hunters is off the Colville Delta, extending as far west as 
Fish Creek and as far east as Pingok Island. The planned seismic 
exploration during the summer has some potential to influence seal 
hunting activities by residents of Nuiqsut. During BP and Western 
Geophysical's 1996-2000 seismic programs, an operating airgun array 
apparently did not displace seals by more than a few hundred meters 
(and usually much less). Therefore, because WesternGeco is proposing 
similar mitigation and consultation procedures this year, it is 
unlikely that seismic activities would have more than a negligible 
impact on Nuiqsut seal hunting.

Anticipated Impact on Habitat

     The proposed seismic activity is not expected to cause significant 
and permanent impacts on habitats used by marine mammals, or to the 
food sources they utilize. The main impact associated with the proposed 
activity will be temporarily elevated noise levels.
    Prey fish often react to sounds, especially strong and/or 
intermittent sounds of low frequency (Chapman and Hawkins, 1969; 
Pearson et al., 1992; Skalski et al., 1992). Fish often habituate to 
repeated strong sounds rather rapidly, on time scales of minutes to an 
hour. However, the habituation does not endure, and resumption of the 
disturbing activity may again elicit disturbance responses from the 
same fish. Fish near the airgun arrays are likely to dive to the bottom 
or exhibit some other kind of behavioral response (WesternGeco, 2001). 
This would likely have little or no impact on seal or beluga whale 
feeding in the shallow areas where seismic work is planned.
    Many crustaceans can make sounds and some Crustacea and other 
invertebrates have some type of sound receptor. However, the reactions 
of zooplankton and benthic animals, the primary prey species of bowhead 
and gray whales, to sound are not known. Zooplankton may react to the 
shock wave from an airgun array when they occur very close to the 
source. However, little or no mortality is expected. A reaction by 
zooplankton to a seismic impulse would only be relevant to bowhead 
whales if it caused a concentration of zooplankton to scatter. Pressure 
changes of sufficient magnitude to cause this type of reaction would 
probably occur only very close to the source. Impacts on zooplankton 
behavior are predicted to be negligible and this would translate into 
negligible impacts on feeding bowhead whales.
    Physical contact with the ocean bottom by cables and ancillary 
equipment will be temporary and in a very small fraction of the 
potential survey area. The use of OBCs could result in some short-term 
disturbance to sediments and benthic organisms in the immediate area of 
the cable. Recovery of disturbed soft-bottom areas will occur in a 
manner similar to that occurring after natural disturbances by ice 
scour.
    The 2001 OBC survey area may overlap with areas identified as 
``Boulder Patch'' habitat. If such overlap occurs, WesternGeco will 
adhere to any applicable requirements identified by the responsible 
governmental agencies.

Mitigation

    For the 2001 seismic operations, WesternGeco will reduce its 
primary airgun array from the 1,500 in\3\ used in 1998 to 1,210 in\3\. 
This reduction in volume will lower the source levels and result in 
lower received levels at each distance compared to Western 
Geophysical's 1998 project. The smaller volume 640 in\3\ airgun array 
consists of sixteen 40 in\3\ airguns in four 4-gun clusters. The 
airguns comprising this small volume array will be spread out 
horizontally, such that the energy from the array, like that from the 
1,210 in\3\ array, will be directed downward as far as possible. The 
distances within which received levels (see the proposed safety radii 
below) can exceed 190 dB and 180 dB re 1 micro-Pa have been measured at 
two airgun depths (2.3 and 5 m or 7.5 and 16.4 ft) and in two water 
depths (8 and 23 m or 26.2 and 75.5 ft) (Greene and McLennan, 2000), 
and are reduced relative to those around the 1998 array. The shallower 
depth at which the 640 in\3\ array will operate will tend to reduce the 
source level (and hence the 190 and 180 dB safety radii) even farther; 
however, as a precautionary approach, the 190 and 180 dB radii for the 
1,210 in\3\ airgun operating at 2.3 m (7.5 ft) depth will be assumed to 
apply to the 640 in\3\ array operating at 1 m (3.3 ft) gun depth.
    Proposed safety radii for OBC seismic operations in 2001 are based 
on comprehensive measurements of the sounds recorded in the water near 
the OBC array in 1999 and analyzed by Greene and McLennan (2000).
    Vessel-based observers will monitor marine mammal presence in the 
vicinity of the seismic arrays throughout the seismic program. To avoid 
the potential for injury, WesternGeco proposes to immediately shut down 
the seismic source if seals and/or whales are sighted within the 
proposed safety radii. The proposed safety radii are as follows:

----------------------------------------------------------------------------------------------------------------
                                                                                           SAFETY RADII(m/ft)
                                                                                       -------------------------
           SOURCE (in\3\)               AIRGUN DEPTH (m/ft)       WATER DEPTH (m/ft)       190 dB       180 dB
                                                                                          (Seals)      (Whales)
----------------------------------------------------------------------------------------------------------------
1210                                                  2.3/7.5                <10/<32.8          100          150
1210                                                  2.3/7.5                >10/>32.8          160          550
1210                                                   5/16.4                  10/32.8          160          350
1210                                                   5/16.4                >10/>32.8          260          900
640                                                     1/3.3                <10/<32.8          100          150
640                                                     1/3.3                >10/>32.8          160          550
----------------------------------------------------------------------------------------------------------------

    In addition, WesternGeco proposes to ramp-up the 1,210 in\3\ and 
640 in\3\ seismic sources to operating levels at a rate no greater than 
6 dB per minute. Under normal operational conditions (source vessel 
speed at least 4 knots), a ramp-up would be required after the array 
has been inactive for a period lasting 1 minute or longer. If the 
towing speed is reduced to 3 knots or less, it is proposed that a ramp-
up would be required after the array has been inactive for a period 
lasting 2 minutes or longer. Ramp-up will begin with an air volume 
discharge not exceeding 80

[[Page 32326]]

 in\3\ for the 1,210 in\3\, and 40 in\3\ for the 640 in\3\ array. 
Additional guns will be added at appropriate intervals so as to limit 
the rate of increase in source level to 6 dB per minute.

Monitoring

    As part of its application, WesternGeco provided a monitoring plan 
for assessing impacts to marine mammals from seismic surveys in the 
Beaufort Sea. This monitoring plan is described in WesternGeco (2001) 
and in LGL, Ltd. and Greeneridge Sciences Inc. (2001). As required by 
the MMPA, this monitoring plan will be subject to a peer-review panel 
of technical experts prior to formal acceptance by NMFS.
    WesternGeco plans to conduct the following monitoring:

Vessel-based Visual Monitoring

     It is proposed that one or two marine mammal observers aboard the 
seismic source vessel will search for and observe marine mammals 
whenever seismic operations are in progress and for at least 30 minutes 
before the planned start of seismic transmissions. These observers will 
scan the area immediately around the vessels with reticle binoculars 
during the daytime. Laser rangefinding binoculars will be available to 
assist with distance estimation. If operations continue after mid-
August, when the duration of darkness increases, image intensifiers and 
additional light sources will be used to illuminate the safety zone 
(see application for more detail).
    A total of four observers (three trained biologists and one Inupiat 
observer/communicator) will be based aboard the seismic source vessel 
Arctic Star. They will work in teams of two, with individual watches 
limited to no more than 4 consecutive hours.
    A total of two observers will be based aboard the seismic source 
vessel Peregrine. Individual watches will be limited to no more than 4 
consecutive hours. In addition, wheelhouse staff aboard the Peregrine 
will assist in maintaining a watch for marine mammals. If operations 
continue for substantially more than 12 hours per day, 1 or 2 
additional observers will be required on a rotating basis.
    When marine mammals are detected within or about to enter the 
safety zone designated to prevent injury to the animals (see 
Mitigation), the geophysical crew leader will be notified and the 
airgun(s) will be shut down immediately.

Aerial Surveys

    If OBC seismic work continues after August 31, 2001, aerial surveys 
by WesternGeco's marine mammal contractor, LGL Ltd., would occur from 
the date on which OBC seismic operations commence until 1 day after the 
OBC seismic operations end. If OBC seismic work is suspended during the 
bowhead subsistence hunting season, but resumes later in the autumn, 
aerial surveys will commence (or resume) when OBC seismic work resumes. 
WesternGeco proposes to continue aerial surveys until 1 day after OBC 
seismic work ends.
    The primary objective of the aerial surveys will be to document the 
occurrence, distribution, and movements of bowhead whales, and 
(secondarily) beluga and gray whales in and near the area where they 
might be affected by the seismic pulses. These observations will be 
used to estimate the level of harassment takes and to assess the 
possibility that seismic operations affect the accessibility of bowhead 
whales for subsistence hunting. Pinnipeds will be recorded when seen, 
although survey altitude will be too high for systematic surveys of 
seals. Sonobuoys will be dropped to document seismic and ambient noise 
at offshore locations, including locations near whales.
    WesternGeco proposes to fly at 300 m (1,000 ft) in areas where no 
whaling is underway, but it may reduce that altitude to no less than 
275 m (900 ft) under low cloud conditions. In addition, and subject to 
the terms of the 2001 CAA with subsistence communities, surveys may be 
flown at 457 m (1500 ft) altitude over areas where whaling is occurring 
on that date and should avoid direct overflights of whaleboats and 
Cross Island, where whalers from Nuiqsut are based during their autumn 
whale hunt.
    The daily aerial surveys are proposed to cover a grid of 18 north-
south lines spaced 8 km (5 mi) apart and extending seaward to about the 
100 m (328 ft) depth contour (typically about 65 km (40.4 mi) 
offshore). This grid will extend from about 65 km (40.3 mi) east to 65 
km (40.3 mi) west of the area in which seismic operations are underway 
on that date. This survey design will provide extended coverage to 
determine the eastward and westward extent of the offshore displacement 
of whales by seismic operations. In 2001, no ``intensive'' grid surveys 
are planned to be conducted because very few whales occur within 20 km 
(12.4 mi) of the seismic operation.
    Detailed information on the aerial survey program can be found in 
WesternGeco(2001) and in LGL Ltd. and Greeneridge Sciences Inc. (2001), 
which are incorporated in this document by citation.

Acoustical Measurements

    The acoustic measurement program proposed for 2001 is designed to 
provide, in conjunction with existing results from previous years (see 
LGL and Greeneridge Sciences Inc., 1997, 1998, 1999), the specific 
acoustic data needed to document the seismic sounds to which marine 
mammals will be exposed in 2001. Proposed emphasis is on situations and 
locations not studied in detail during previous operations.
    WesternGeco has two basic objectives for collecting acoustic 
measurements, one physical and one biological. The physical acoustics 
objective is to determine the characteristics of airgun array pulses as 
received in the bowhead migration corridor at varying distances 
offshore and to the east of the area of seismic exploration in 2001 and 
in 1996-98 plus 2001 combined. Pulse characteristics to be determined 
are received levels and pulse durations versus range offshore and to 
the east, spectral properties, and signal-to-ambient ratios. These 
measurements will only be made if seismic operations continue into 
September/October. The biological objective is to determine whether 
there are differences in the pattern of bowhead call detection rates 
near, offshore of, and east of the seismic exploration area at times 
with and without active seismic operations based on 2001 data and 
combined 1996-98 and 2001 data. If there are differences, then 
WesternGeco proposes to use the combined acoustic and aerial survey 
data to evaluate whether the noise-related differences in call 
detection rate are attributable to differences in calling behavior, 
whale distribution, or a combination of the two.
    In 2001, the acoustic measurement program is planned to include (1) 
deployment in late August/September of autonomous seafloor acoustic 
recorders (ASARs) to provide continuous acoustic data for extended 
periods, and (2) use of air-dropped sonobuoys in September/October. 
WesternGeco proposes to use these methods only if OBC surveys occur in 
September/October.
    (1) The ASARs would be placed on the sea bottom at three locations 
in late August or September if OBC seismic work extends into the 
September/October 2001 period. This method provides a large number of 
measurements of received characteristics of seismic pulses in the whale 
migration corridor well offshore and east of the area of OBC seismic 
exploration. ASARs would also provide continuous data on whale calling

[[Page 32327]]

 patterns at times with and times without airgun operations. These 
recorders would also collect data on ambient noise levels.
    (2) Sonobuoys would be dropped and monitored from survey aircraft 
during September/October (if the seismic operations are continuing at 
that time) at an average rate of about two sonobuoys per day of aerial 
surveys on days when bowhead whales are seen. This method provides data 
on received levels and other characteristics of seismic pulses received 
in the bowhead whale migration corridor, including some of the specific 
locations where bowhead whales are observed. Sonobuoys would also 
provide the ambient noise data needed to estimate signal-to-noise 
ratios for seismic pulses received by whales.
    For a more detailed description of planned monitoring activities, 
please refer to the application and the Technical Monitoring Plan 
(WesternGeco, 2001; LGL Ltd. and Greeneridge Sciences Inc., 2001).

Reporting

    WesternGeco will provide an initial report on 2001 activities to 
NMFS within 90 days after the end of the seismic program. This report 
will summarize dates and locations of seismic operations, marine mammal 
sightings (dates, times, locations, behaviors, associated seismic 
survey activities), estimates of the amount and nature of all takes by 
harassment or in other ways, and any apparent effects on accessibility 
of marine mammals to subsistence users.
    A final technical report will be provided by WesternGeco no later 
than April 30, 2002. The final technical report will contain a 
description of the methods, results, and interpretation of all 
monitoring tasks.

Consultation

    Under section 7 of the Endangered Species Act (ESA), NMFS completed 
an informal consultation on the issuance of an IHA for similar 
activities on July 26, 1999. If an authorization to incidentally harass 
listed marine mammals is issued under the MMPA for this activity, NMFS 
will issue an Incidental Take Statement under section 7 of the ESA.

National Environmental Policy Act (NEPA)

    In 1999, NMFS conducted an environmental assessment (EA) on the 
impacts of conducting seismic surveys during the open water season in 
the U.S. Beaufort Sea. In that analysis NMFS determined that neither 
the authorization for the harassment of small numbers of several 
species of marine mammals incidental to conducting seismic surveys nor 
the alternatives to that action would significantly affect the quality 
of the human environment. Since this proposed action by WesternGeco, 
LLC does not differ from actions previously analyzed by NMFS under the 
1999 EA, this action is categorically excluded from further NEPA review 
(NOAA NAO 216-6). A copy of the 1999 EA is available upon request (see 
ADDRESSES).

Preliminary Conclusions

    NMFS has preliminarily determined that the short-term impact of 
conducting seismic surveys in the Alaskan Beaufort Sea will result, at 
worst, in a temporary modification in behavior by certain species of 
cetaceans and possibly by pinnipeds. While behavioral modifications may 
be made by these species to avoid the resultant noise, this behavioral 
change is expected to have a negligible impact on the animals.
    While the number of potential incidental harassment takes will 
depend on the annual variability in distribution and abundance of 
marine mammals within the area of seismic operations, due to the 
distribution and abundance of marine mammals during the projected 
period of activity and the location of the proposed seismic activity in 
waters generally too shallow and distant from the edge of the pack ice 
for most marine mammals of concern, the number of potential harassment 
takings is estimated to be small. In addition, no take by injury and/or 
death is anticipated, and the potential for temporary or permanent 
hearing impairment will be minimized through the incorporation of the 
mitigation measures mentioned in this document. No rookeries, mating 
grounds, year-round areas of concentrated feeding, or other areas of 
special significance for marine mammals occur within or near the 
planned area of operations during the season of operations.
    Because bowhead whales are east of the seismic area in the Canadian 
Beaufort Sea until late August/early September, seismic activities are 
not expected to impact subsistence hunting of bowhead whales prior to 
that date. After August 31, 2001, until 1 day after the OBC seismic 
operations end, aerial survey flights for bowhead whale assessments are 
proposed to be undertaken by WesternGeco. If OBC seismic work is 
suspended during the bowhead subsistence hunting season, but resumes 
later in the autumn, aerial surveys will commence (or resume) when OBC 
seismic work resumes. The proposed duration for aerial surveys will be 
a reduction from previous years. WesternGeco believes this reduction is 
appropriate because some of the main questions about disturbance to 
bowhead whales from a nearshore seismic operation were answered by the 
1996-1998 monitoring projects. In addition, the MMS expects to conduct 
its broad-scale aerial survey work from approximately August 31 until 
the end of the bowhead migration in October. WesternGeco believes that 
this combined aerial survey data will provide sufficient information to 
estimate the numbers of bowhead whales taken by harassment.
    Appropriate mitigation measures to avoid an unmitigable adverse 
impact on the availability of bowhead whales for subsistence needs will 
be the subject of consultation between WesternGeco and subsistence 
users.
    Open-water seismic exploration in the Alaskan Beaufort Sea does 
have some potential to influence seal hunting activities by residents 
of Nuiqsut. However, because the main summer sealing by the village of 
Nuiqsut is conducted off the Colville Delta, west of the proposed 
survey area, and the zone of influence by seismic sources on seals is 
expected to be fairly small (less than a few hundred meters), NMFS 
believes that WesternGeco's OBC seismic survey will not have an 
unmitigable adverse impact on the availability of seals for subsistence 
uses.

Proposed Authorization

    Provided the previously mentioned mitigation, monitoring, and 
reporting requirements are incorporated, NMFS proposes to issue an IHA 
to WesternGeco for an OBC seismic survey during the 2001 Alaskan 
Beaufort Sea open water season. NMFS has preliminarily determined that 
the proposed seismic activity would result in the harassment of only 
small numbers of bowhead whales, beluga whales, ringed seals, bearded 
seals, and possibly spotted seals and gray whales; would have no more 
than a negligible impact on these marine mammal stocks; and would not 
have an unmitigable adverse impact on the availability of marine mammal 
stocks for subsistence uses.

Information Solicited

    NMFS requests interested persons to submit comments, and 
information, concerning this request (see ADDRESSES).


[[Page 32328]]


    Dated: June 7, 2001.
Wanda L. Cain,
Acting Deputy Director, Office of Protected Resources.
[FR Doc. 01-15060 Filed 6-13-01; 8:45 am]
BILLING CODE 3510-22-S