[Federal Register Volume 65, Number 79 (Monday, April 24, 2000)]
[Notices]
[Pages 21720-21726]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-10156]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[I.D. 032800A]


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: 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 Western Geophysical/Western 
Atlas International of Houston, Texas (Western Geophysical) for an 
authorization to take small numbers of marine mammals by harassment 
incidental to conducting seismic surveys in the Beaufort Sea in state 
and Federal waters. Under the Marine Mammal Protection Act (MMPA), NMFS 
is requesting comments on its proposal to authorize Western Geophysical 
to incidentally take, by harassment, small numbers of bowhead whales 
and other marine mammals in the above mentioned areas during the open 
water period of 2000.

DATES: Comments and information must be received no later than May 24, 
2000.

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, 
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: Kenneth R. Hollingshead, (301) 713-
2055, ext 128, Brad Smith, (907) 271-5006.

[[Page 21721]]


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 February 14, 2000, NMFS received an application from Western 
Geophysical requesting an authorization for the harassment of small 
numbers of several species of marine mammals incidental to conducting 
seismic surveys during the open water season in the south central 
Beaufort Sea between western Camden Bay and Harrison Bay off Alaska. 
Weather permitting, the survey is expected to take place between 
approximately July 1 and mid- to late-October, 2000. However, only a 
small portion of this area will be surveyed this year. A detailed 
description of the work proposed for 2000 is contained in the 
application (Western Geophysical, 2000) which is available upon request 
(see ADDRESSES).

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 does not need to be 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 (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), the annual monitoring reports for seismic surveys 
in the Beaufort Sea (LGL Ltd. and Greeneridge Sciences Inc, 1997, 1998, 
and 1999) and several other documents (Corps of Engineers, 1999; 
Lentfer, 1988; MMS, 1992, 1996; Hill et al., 1999). 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.
    Seismic surveys are used to obtain data about formations several 
thousands of feet deep. The proposed seismic operation is an ocean 
bottom cable (OBC) survey. For this activity, OBC surveys involve 
dropping cables from a ship to the ocean bottom, forming a patch 
consisting of 4 parallel cables 8.9 kilometers (km) (5.5 miles (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 underground rock strata. 
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. The source level planned for this project--a maximum of 247 
dB re 1 <greek-m>Pa-m or 22.3 bar-meters (zero to peak), or a maximum 
of 252 dB (re 1 <greek-m>Pa-m or 39 bar-meters (peak-to-peak)--will be 
from an airgun array with a air discharge volume of 1,210 
in<SUP>3</SUP>. In addition to this seismic source, Western Geophysical 
also plans to use a 40-in<SUP>3</SUP> airgun with a source level of 210 
dB (re 1 <greek-m>Pa-m), a Sub-bottom Profiler, a Geo-pulse unit, and 
two side-scan sonar units, one of 100 kHz and a one of 500 kHz unit.
    It is anticipated that the seismic vessel 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 for adjacent patches. Western 
Geophysical anticipates completing 18 patches during the 2000 open-
water season.
    After sufficient data have been recorded to allow accurate mapping 
of the rock strata, the cables are lifted onto the deck of a cable-
retrieval vessel, moved to a new location (ranging from several hundred 
to a few thousand feet away), and placed onto the seabed again. For a 
more detailed description of the seismic operation, please refer to 
Western Geophysical (2000).
    Depending upon ambient noise conditions and the sensitivity of the 
receptor, underwater sounds produced by open water seismic operations 
may be detectable a substantial distance away from the activity. Any 
sound that is detectable is (at least in theory) capable of eliciting a 
disturbance reaction by a marine mammal or of masking a signal of 
comparable frequency (Western Geophysical, 2000). 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 react to the generated sounds or to visual cues.
    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). Results from the 1996-1998 BP and Western 
Geophysical seismic program monitoring 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

[[Page 21722]]

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). Because recent seismic work 
have been conducted in shallow water, have been limited to a confined 
area at any one time, and have employed smaller arrays of airguns than 
those that were often used in the past, Western Geophysical believes 
that avoidance distances around nearshore seismic operations conducted 
this year will likely be less than those around some of the seismic 
operations conducted before 1996.
    Although some limited masking of low-frequency sounds (e.g., whale 
calls) is a possibility, 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 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 temporary threshold shift 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, bowhead whales 
avoid an area many kilometers in radius around ongoing seismic 
operations, precluding any possibility of hearing damage.
    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 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.

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 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 
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).
    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, 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 <greek-m>Pa). By some behavioral measures, 
clear effects were evident at average pulse levels of 160+dB; 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 (Odontoceti) 
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 
<greek-m>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 sometimes may 
be audible to beluga 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 beluga, 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 (Western Geophysical, 2000).

Ringed, Largha 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

[[Page 21723]]

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 <greek-m>Pa @ 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 <greek-m>Pa @ 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. 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 (Western Geophysical, 2000). 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

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

------------------------------------------------------------------------
                                                Harassment Takes in 2000
             Species                Population -------------------------
                                       Size       Possible     Probable
------------------------------------------------------------------------
Bowhead                                  8,200
160 dB criterion                             -        1,020          500
20 km criterion                              -        2,500        1,275
Gray whale                              26,600           10            0
Beluga                                  39,258          250          150
Ringed seal*                             1-1.5          400          200
                                       million
Spotted seal*                         >200,000           10            2
Bearded seal*                         >300,000           50          15
------------------------------------------------------------------------
* Some individual seals may be harassed more than once

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 bowheads become more skittish when exposed to 
seismic noise.
    Nuiqsut is the community closest to the area of the proposed 
activity, and it harvests bowhead whales only during the fall whaling 
season. In recent years, Nuiqsut whalers typically take two to four 
whales each season (Western Geophysical, 2000). Nuiqsut whalers 
concentrate their efforts on areas north and east of Cross Island, 
generally in water depths greater than 20 m
    (65 ft). Cross Island, the principle field camp location for 
Nuiqsut whalers, is located within the general area of the proposed 
2000 seismic area. Thus, the possibility and timing of potential 
seismic operations in the Cross Island area requires Western 
Geophysical to provide NMFS with either a Plan of Cooperation with 
North Slope Borough residents or measures that have been or will be 
taken to avoid any unmitigable adverse impact on subsistence needs. 
Western Geophysical's application has identified those measures that 
will be taken to minimize any adverse effect on subsistence. In 
addition, the timing of seismic operations in and east of the Cross 
Island area will be addressed in a Conflict and Avoidance Agreement 
(C&AA) with the Nuiqsut whalers and the AEWC (Western Geophysical, 
2000).
    Whalers from the village of Kaktovik search for whales east, north, 
and west of the village. Kaktovik is located 60 km (37.3 mi) east of 
the easternmost end of Western Geophysical's planned 2000 seismic 
exploration area. The westernmost reported harvest location was about 
21 km (13 mi) west of Kaktovik, near 70 deg.10 N', 144 deg. W (Kaleak, 
1996). That site is approximately 40 km (24.7 mi) east of the closest 
part of Western Geophysical's planned seismic exploration area for 2000 
(Western Geophysical, 2000).
    Whalers from the village of Barrow search for bowhead whales much 
further from the planned seismic area, >200 km (>125 mi) west (Western 
Geophysical, 2000).
    The location of the proposed seismic activity is south of the 
center of the westward migration route of bowhead whales, but there is 
some overlap. Seismic monitoring results from 1996-1998 indicate that 
most bowheads avoid the area within about 20 km (12.4 mi) around the 
array when it is operating, and some avoid the area within 30 km (18.6 
mi). In addition, bowheads 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.
    Western Geophysical (2000) believes it is unlikely that changes in 
migration

[[Page 21724]]

route will occur at distances greater than 25 km (15.5 mi) from an 
array of maximum volume of 1,210 in<SUP>3</SUP> operating in water less 
than 30 m (100 ft) deep. However, subtle changes in behavior might 
occur out to longer distances. Inupiat whalers believe that bowheads 
begin to divert from their normal migration path more than 35 miles 
away (MMS, 1997).
    It is recognized that it is difficult to determine the maximum 
distance at which reactions occur (Moore and Clark, 1992). As a result, 
Western Geophysical will participate in a C&AA with the whalers to 
reduce any potential interference with the hunt. Also, it is believed 
that the monitoring plan proposed by Western Geophysical (2000) will 
provide information that will help resolve uncertainties about the 
effects of seismic exploration on the accessibility of bowheads to 
hunters.
    Many Nuiqsut hunters hunt seals intermittently year round. However, 
during recent years, most seal hunting has been during the early summer 
in open water. In summer, 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. This area overlaps with the westernmost portion of the 
planned seismic area. In this area, during summer, sealing occurs by 
boat when hunters apparently concentrate on bearded seals. However, 
these subsistence hunters have not perceived any interference between 
recent open-water seismic activities in the Alaskan Beaufort Sea. 
Therefore, because Western Geophysical 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.

Mitigation

    For the second year, Western Geophysical will reduce its airgun 
array from the 1,500 in<SUP>3</SUP> used in 1998 to 1,210 
in<SUP>3</SUP>. This reduction in source level will result in lower 
received levels and, therefore, smaller safety ranges and fewer takes 
by harassment than those in 1998. However, because the 1,210 
in<SUP>3</SUP> array is a subset (with some minor variations) of the 
1,500 in<SUP>3</SUP> array (with four guns not firing), NMFS again this 
year proposes to limit Western Geophysical's active airguns so that 
they do not exceed a capacity of 1,210 in<SUP>3</SUP> during the 2000 
open water seismic survey.
    Vessel-based observers will monitor marine mammal presence in the 
vicinity of the seismic array throughout the seismic program. To avoid 
the potential for injury to seals, Western Geophysical proposes to 
immediately power down the seismic source if seals are sighted within 
the area delineated by the 190 dB isopleth. In water depth less than 10 
m (33 ft), Western Geophysical will establish safety zones 240 m (787.4 
ft) from the array when the array is operating at 5 m (16.4 ft) depth 
and 90 m (295.3 ft) from the array when it is operating at 2.3 m (7.5 
ft) depth. In water depth greater than 10 m (33 ft), Western 
Geophysical will establish safety zones 260 m (853 ft) from the array 
when the array is operating at 5 m (16.4 ft) depth and 150 m (492 ft) 
from the array when it is operating at 2.3 m (7.5 ft) depth.
    To avoid the potential for injury to whales, Western Geophysical 
will immediately power down the seismic source if bowhead, gray, or 
beluga whales are sighted within the area delineated by the 180 dB 
isopleth. In water depth less than 10 m (33 ft), Western Geophysical 
will establish safety zones 750 m (2,460.6 ft) from the array when the 
array is operating at 5 m (16.4 ft) depth and 360 m (1,181.1 ft) from 
the array when it is operating at 2.3 m (7.5 ft) depth. In water depth 
greater than 10 m (33 ft), Western Geophysical will establish safety 
zones 1000 m (3281 ft) from the array when the array is operating at 5 
m (16.4 ft) depth and 600 m (1968.5 ft) from the array when it is 
operating at 2.3 m (7.5 ft) depth.
    Different safety radii will be established for shallow-hazard 
survey operations. Received levels of sounds from a single 40 
in<SUP>3</SUP> airgun operating at a depth of 1 m (3 ft) are expected 
to diminish below 190 and 180 dB (re 1 <greek-m>Pa RMS) at distances of 
22 m (72.2 ft), and 100 m (328.1 ft), respectively. These estimates are 
based on extensive measurements of sounds from operations with a single 
airgun and a small array of airguns in the same area during 1996-97 
(Western Geophysical, 2000). Because the GeoPulse and the sub-bottom 
profiler will normally be operated simultaneously with the airgun, and, 
because these units are less powerful than the airgun, separate safety 
zones do not need to be established for them. As previously done, 
operations using these sources will be terminated whenever a seal or 
whale enters its respective safety zone.
    Within the first 10 days of Beaufort Sea operations in 2000, 
Western Geophysical will measure and analyze the sounds from Western's 
2000 array operating at both 5 m (16.4 ft) and 2 m (6.6 ft) depths. 
This information will be provided to NMFS, along with the contractor's 
recommendation as to whether any adjustments in the safety radii are 
needed to meet the 190 and 180 dB<INF>rms</INF> shutdown criteria.
    In addition, Western Geophysical proposes to ramp-up the 1,210 
in<SUP>3</SUP> seismic source to operating levels at a rate no greater 
than 6 dB/min anytime the array has not been firing for 1 minute at a 
vessel speed of 4 to 8 knots and 2 minutes at a vessel speed of 3 knots 
or slower. Ramp-up will begin with an air volume discharge not 
exceeding 80 in<SUP>3</SUP> with additional guns added at intervals 
appropriate to limit the rate of increase to 6 dB/min. No ramp-up is 
proposed for the smaller acoustic sources.

Monitoring

    As part of its application, Western Geophysical provided a 
monitoring plan for assessing impacts to marine mammals from seismic 
surveys in the Beaufort Sea. This monitoring plan is described in 
Western Geophysical (2000) and in LGL Ltd. (2000). 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.
    Western Geophysical plans to conduct the following monitoring:

Vessel-based Visual Monitoring

    It is proposed that one or two marine mammal observers aboard the 
seismic 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. After mid-August, when the duration of 
darkness increases, image intensifiers will be used by observers 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 vessel. As in 
1999, the use of four observers is an increase over the three observers 
used in 1998 and will allow two observers to be on duty simultaneously 
for up to 50 percent of the active airgun hours. The use of two 
observers will increase the probability of detecting marine mammals, 
and two observers will be required to be on duty whenever the seismic 
array is ramped up. Individual watches will normally be limited to no 
more than 4 consecutive hours.

[[Page 21725]]

    When mammals are detected within or about to enter the safety zone 
designated to prevent injury to the animals (see Mitigation), the 
geophysical crew leader will be notified so that shutdown procedures 
can be implemented immediately.

Aerial Surveys

    Between September 1, 2000, until 1 day after the OBC seismic 
operations end or until September 15 (whichever comes first), aerial 
survey flights for bowhead whale assessments are proposed to be 
undertaken by Western Geophysical. 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. Western Geophysical proposes to continue aerial surveys either 
until 1 day after OBC seismic work ends, or until a total of 15 days of 
aerial surveys have been conducted during September-October 2000, 
whichever comes first. It should be noted that the proposed duration 
for aerial surveys would be a reduction from previous years. Western 
Geophysical believes this reduction is appropriate because some of the 
main questions about disturbance to bowhead whales from a nearshore 
seismic operation have been answered through the 1996-1998 monitoring 
projects. In addition, MMS expects to conduct its broad-scale aerial 
survey work from approximately 31 August until the end of the bowhead 
migration in October. Western Geophysical believes that this combined 
aerial survey data will provide sufficient information to estimate the 
numbers of bowheads taken by harassment.
    The primary objective of the aerial surveys will be to document the 
occurrence, distribution, and movements of bowhead, as well as 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.
    Western Geophysical 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 274 m (900 ft) under low cloud conditions. In addition, 
surveys will be flown at 457 m (1500 ft) altitude over areas where 
whaling is occurring on that date and will avoid direct overflights of 
whaleboats and Cross Island, where whalers from Nuiqsut are based 
during their fall whale hunt.
    The daily aerial surveys are proposed to cover a grid of 18 north-
south lines spaced 8 km (5 mi) apart and will extend seaward to about 
the 100 m (328 ft) depth contour (typically about 65 km (40.4 mi) 
offshore. This grid will extend from about 40 km (24.8 mi) east to 40 
km (24.8 mi) west of the area in which seismic operations are underway 
on that date. This design will provide extended coverage to the west to 
determine the westward extent of the offshore displacement of whales by 
seismic. In 2000, no ``intensive'' grid surveys are planned to be 
conducted by Western Geophysical because very few whales occur within 
20 km (12.4 mi) of the seismic operation.
    Detailed information on the survey program can be found in Western 
Geophysical (2000) and in LGL Ltd. (2000), which are incorporated in 
this document by citation.

Acoustical Measurements

    The acoustic measurement program proposed for 2000 is designed to 
be continue work conducted in 1996 through 1999 (see LGL and 
Greeneridge Sciences Inc., 1997, 1998, 1999). The acoustic measurement 
program is planned to include (1) vessel-based hydrophone measurements, 
(2) use of air-dropped sonobuoys during OBC operations in September and 
October, and (3) bottom-mounted acoustical recorders.
    (1) If shallow-water hazards surveys are conducted, a vessel-based 
acoustical measurement program is proposed for a few days early in that 
program. The objectives of this survey will be as follows: (a) To 
measure the levels and other characteristics of the horizontally 
propagating sounds from the single airgun, GeoPulse, and sub-bottom 
profiler to be used in 2000 as a function of distance relative to the 
source and (b) to measure the levels and frequency composition of the 
vessel sounds emitted by vessels used regularly during Western's 2000 
program in those cases where these vessels have not previously been 
measured adequately.
    (2) Sonobuoys will be dropped and monitored from survey aircraft 
during September/October (if the seismic operations are continuing at 
that time). Sonobuoys will provide data on characteristics of seismic 
pulses (and signal-to-ambient ratios) at offshore locations, including 
some of the specific places where bowhead whales are observed.
    (3) Autonomous seafloor acoustic recorders will be placed on the 
sea bottom at three locations to record low-frequency sounds 
continuously over an extended period of time (if seismic operations 
extend into September/October). The objective is to obtain continuous 
records of seismic sound pulses, ambient noise, and bowhead calls.
    For a more detailed description of planned monitoring activities, 
please refer to the application and the Technical Monitoring Plan 
(Western Geophysical, 2000; LGL Ltd., 2000).

Estimates of Marine Mammal Take

    Estimates of takes by harassment will be made through vessel and 
aerial surveys. Preliminarily, Western Geophysical will estimate the 
number of (a) marine mammals observed within the area ensonified 
strongly by the seismic vessel; (b) marine mammals observed showing 
apparent reactions to seismic pulses (e.g., heading away from the 
seismic vessel in an atypical direction); (c) marine mammals subject to 
take by type (a) or (b) when no monitoring observations were possible; 
and (d) bowheads displaced seaward from the main migration corridor.

Reporting

    Western Geophysical will provide an initial report on 2000 
activities to NMFS within 90 days of the completion of the seismic 
program. This report will provide dates and locations of seismic 
operations, details of marine mammal sightings, estimates of the amount 
and nature of all takes by harassment, and any apparent effects on 
accessibility of marine mammals to subsistence users.
    A final technical report will be provided by Western Geophysical 
within 20 working days of receipt of the document from the contractor, 
but no later than April 30, 2001. 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 conjunction with the 1996 notice of proposed authorization (61 
FR 26501, May 28, 1996) for open water seismic operations in the 
Beaufort Sea, NMFS released an EA that addressed the

[[Page 21726]]

impacts on the human environment from issuance of the authorization and 
the alternatives to the proposed action. No comments were received on 
that document and, on July 18, 1996, NMFS concluded that neither 
implementation of the proposed authorization for the harassment of 
small numbers of several species of marine mammals incidental to 
conducting seismic surveys during the open water season in the U.S. 
Beaufort Sea nor the alternatives to that action would significantly 
affect the quality of the human environment. As a result, the 
preparation of an environmental impact statement on this action is not 
required by section 102(2) of NEPA or its implementing regulations.
    In 1999, NMFS determined that a new EA was warranted based on the 
proposed construction of the Northstar project, the collection of data 
from 1996 through 1998 on Beaufort Sea marine mammals and the impacts 
of seismic activities on these mammals, and the analysis of scientific 
data indicating that bowheads avoid nearshore seismic operations by up 
to about 20 km (12.4 mi). Accordingly, a review of the impacts expected 
from the issuance of an IHA has been assessed in both the EA and in 
this document, and NMFS has determined that there will be no more than 
a negligible impact on marine mammals from the issuance of the 
harassment authorization and that there will not be any unmitigable 
impacts to subsistence communities, provided the mitigation measures 
required under the authorization are implemented. As a result, NMFS 
determined that neither implementation of the authorization for the 
harassment of small numbers of several species of marine mammals 
incidental to conducting seismic surveys during the open water season 
in the U.S. Beaufort Sea nor the alternatives to that action would 
significantly affect the quality of the human environment. As a result, 
the preparation of additional NEPA documentation on this action is not 
required by section 102(2) of NEPA or by its implementing regulations.

Conclusions

    NMFS has preliminarily determined that the short-term impact of 
conducting seismic surveys in the U.S. 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 distribution and abundance of marine mammals (which vary 
annually due to variable ice conditions and other factors) in 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 avoided 
through the incorporation of the mitigation measures mentioned in this 
document. No rookeries, mating grounds, areas of concentrated feeding, 
or other areas of special significance for marine mammals occur within 
or near the planned area of operations during the season of operations.
    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. Between September 1, 2000, until 1 day after the OBC seismic 
operations end or until September 15 (whichever comes first), aerial 
survey flights for bowhead whale assessments are proposed to be 
undertaken by Western Geophysical. 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. Western Geophysical proposes to continue aerial surveys either 
until 1 day after OBC seismic work ends, or until a total of 15 days of 
aerial surveys have been conducted during September-October 2000, 
whichever comes first. It should be noted that the proposed duration 
for aerial surveys would be a reduction from previous years. Western 
Geophysical believes this reduction is appropriate because some of the 
main questions about disturbance to bowhead whales from a nearshore 
seismic operation have been answered through the 1996-1998 monitoring 
projects. In addition, MMS expects to conduct its broad-scale aerial 
survey work from approximately August 31 until the end of the bowhead 
migration in October. Western Geophysical believes that this combined 
aerial survey data will provide sufficient information to estimate the 
numbers of bowheads 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 Western Geophysical and 
subsistence users.
    Also, while open-water seismic exploration in the U.S. Beaufort Sea 
has some potential to influence seal hunting activities by residents of 
Nuiqsut, because (1) the peak sealing season is during the winter 
months, (2) the main summer sealing is off the Colville Delta, and (3) 
the zone of influence by seismic sources on beluga and seals is fairly 
small, NMFS believes that Western Geophysical's seismic survey will not 
have an unmitigable adverse impact on the availability of these stocks 
for subsistence uses.

Proposed Authorization

    NMFS proposes to issue an IHA for the 2000 Beaufort Sea open water 
season for a seismic survey, provided the previously mentioned 
mitigation, monitoring, and reporting requirements are incorporated. 
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).

    Dated: April 17, 2000.
Donald R. Knowles,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 00-10156 Filed 4-21-00; 8:45 am]
BILLING CODE 3510-22-F