[Federal Register Volume 62, Number 77 (Tuesday, April 22, 1997)]
[Notices]
[Pages 19553-19557]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-10254]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration
[I.D. 040497A]


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 the BP Exploration (Alaska) 
900 East Benson Boulevard, Anchorage, AK 99519 (BPXA) for a renewal of 
an authorization to take small numbers of marine mammals by harassment 
incidental to conducting seismic surveys in and near the Northstar 
Unit, 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 BPXA 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 1997.

DATES: Comments and information must be received no later than May 22, 
1997.

ADDRESSES: Comments on the application should be addressed to Michael 
Payne, Chief, Marine Mammal Division, Office of Protected Resources, 
NMFS, 1315 East-West Highway, Silver Spring, MD 20910-3225. A copy of 
the application, an environmental assessment (EA), an informal section 
7 consultation, the 90-day Report, 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 below.

FOR FURTHER INFORMATION CONTACT: Kenneth R. Hollingshead, Office of 
Protected Resources, NMFS, (301) 713-2055, Brad Smith, Western Alaska 
Field Office, NMFS, (907) 271-5006.

SUPPLEMENTARY INFORMATION:

Background

    Section 101(a)(5) (A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
directs the Secretary of Commerce to allow, upon request, the 
incidental, but not intentional taking of marine mammals by U.S. 
citizens who engage in a specified activity (other than commercial 
fishing) within a specified geographical region if certain findings are 
made and either regulations are issued or, if the taking is limited to 
harassment, notice of a proposed authorization is provided to the 
public for review.
    Permission may be granted if NMFS finds that the taking will have a 
negligible impact on the species or stock(s), will not have an 
unmitigable adverse impact on the availability of the species or 
stock(s) for subsistence uses, and 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 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 March 5, 1997, NMFS received an application from BPXA requesting 
a 1-year renewal of their authorization for

[[Page 19554]]

the harassment of small numbers of several species of marine mammals 
incidental to conducting seismic surveys during the open water season 
within and near the Northstar Unit, in the Beaufort Sea between 
145 deg. 30'W and 150 deg. 30'W, in U.S. waters. Weather permitting, 
the survey is expected to take place between approximately July 1 and 
October 20, 1997. A detailed description of the work planned is 
contained in the application (BPXA 1997) and is available upon request 
(see ADDRESSES). Description of Habitat and Marine Mammal Affected by 
the Activity
    A detailed description of the Beaufort Sea ecosystem and its 
associated marine mammals can be found in the EA prepared for this 
authorization (BPXA 1996b) or in other documents (Minerals Management 
Service (MMS) 1992, 1996) and need not be repeated here. A copy of the 
EA is available upon request (see ADDRESSES).

Marine Mammals

    The Beaufort/Chukchi Seas support a diverse assemblage of marine 
mammals including bowhead whales (Balaena mysticetus), gray whales 
(Eschrichtius robustus), belukha (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 others, can be found in several other documents 
(BPXA 1996b, 1997, Lentfer 1988, MMS 1992, NMFS 1990 and 1996, Small 
and DeMaster 1995). 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. Vessels and aircraft will provide a secondary source of 
noise.
    Deep seismic surveys are used to obtain data about formations 
several thousands of feet deep. The physical presence of vessels and 
aircraft could also lead to non-acoustic effects involving visual or 
other cues. The proposed seismic operation is an ocean bottom cable 
(OBC) survey. OBC surveys involve dropping a cable from a ship to the 
ocean bottom. Sensors (hydrophones) are attached to the cable. These 
hydrophones are used to detect seismic energy reflected back from 
underground rock strata. The original 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 downwards toward the seabed. After sufficient energy has 
been recorded to allow accurate mapping of the rock strata, the cable 
is 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, including numbers of vessels planned for this 
survey, please refer to the application (BPXA 1997).
    Depending upon ambient conditions and the sensitivity of the 
receptor, underwater sounds produced by open water seismic operations 
may be detectable some 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 masking a signal of 
comparable frequency (BPXA 1997). 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 visual cues.
    Seismic pulses are known to cause bowhead whales to behaviorally 
respond within a distance of several kilometers (km) (Richardson et al. 
1995). Although some limited masking of low-frequency sounds (e.g., 
whale calls) is a possibility, the intermittent nature of seismic 
source pulses (1 sec every 6-12 sec) 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 
(Richardson et al. 1986). Masking effects are expected to be absent in 
the case of belukhas, given that sounds important to them are 
predominantly at much higher frequencies than are airgun sounds (BPXA 
1997).
    Hearing damage is not expected to occur during the project. It is 
not known whether a marine mammal very close to an airgun array 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 (Richardson et al. 1995) of the source. However, planned 
monitoring and mitigation measures (described below) are designed to 
detect marine mammals occurring near the array and to avoid exposing 
them to sound pulses that have any possibility of causing hearing 
damage.
    When the received levels of noise exceed some behavioral reaction 
threshold, cetaceans will show disturbance reactions (BPXA 1997). The 
levels, frequencies, and types of noise that will elicit a response 
vary between and within species, individuals, locations and season. 
Behavioral changes may be subtle alterations in surface-respiration-
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 (BPXA 1997).

Bowhead Whales

    Various studies (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. Bowheads exposed to seismic 
pulses from vessels more than 4.5 miles (mi) (7.5 km) 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 (BPXA 1996).
    Within a 3.7-60 mi (6-99 km) range, it has not been possible to 
determine a specific distance at which subtle behavioral changes no 
longer occur (Richardson and Malme 1993), given the high variability 
observed in bowhead whale behavior (BPX 1996).
    Preliminary analysis of the results from BPXA's 1996 seismic 
monitoring program does not provide conclusive evidence about the 
radius of avoidance of bowheads to the seismic program. The peak number 
of bowhead sightings was 10-20 km (6.2-12.3 mi) from shore during no-
seismic periods and 20-30 km (12.3-18.6 mi) from shore during periods 
that may have been influenced by seismic noise. This difference was not 
statistically significant, but the low numbers of sightings precluded 
meaningful interpretation (BPXA 1997).

Gray Whales

    The reactions of gray whales to seismic pulses is similar to those 
of bowheads. 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 about 50 percent showed avoidance when the 
average received pulse level was 170 dB (re 1 Pa @ 1 m). Less 
consistent results were indicated at levels of 140-160 dB.

[[Page 19555]]

Belukha

    The belukha is the only species of toothed whale (Odontoceti) 
expected to be encountered in the Beaufort Sea. Because its hearing 
threshold at frequencies below 100 Hz (where most of the energy from 
airgun arrays is concentrated) is poor (125 dB re 1 Pa @ 1 m) 
or more depending upon frequency (Johnson et al. 1989, Richardson 1991, 
1995), belukha are not predicted to be strongly influenced by seismic 
noise. However, because of the high source levels of seismic pulses, 
airgun sounds may be audible to belukha at large distances (Richardson 
1991, 1995).

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 (J. Parsons as quoted in Greene et al. 1985, Anon. 
1975, Mate and Harvey 1985). These studies indicate that ice seals 
typically either tolerate or habituate to seismic noise produced from 
open water sources.
    Underwater audiograms have been obtained using behavioral methods 
for three species of phocinid seals, ringed, harbor, and harp seals 
(Pagophilus groenlandicus). These audiograms were reviewed in 
Richardson et al. (1995). 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 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 Pa @ 1 m) at 100 Hz (Kastak and Schusterman, 1995a, 
b).
    Because no studies to date have focused on pinniped reaction to 
underwater noise from pulsed, seismic arrays in open water (Richardson 
et al. 1991, 1995), as opposed to in-air exposure to continuous noise, 
substantive conclusions are not possible at this time. However, 
assuming a sound pressure level needed to be 80-100 dB over its 
threshold in order to cause annoyance and 130 dB for injury (pain), as 
is the current thought based upon human studies (ARPA and NMFS 1995), 
then it appears unlikely that pinnipeds would be harassed or injured by 
low frequency sounds from a seismic source unless they were within 
close proximity of the array. For permanent injury, marine mammals 
would need to remain in the high noise field for extended periods of 
time. Existing evidence also suggests that, while they may be capable 
of hearing sounds from seismic arrays, seals 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/WDFW 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 Western Beaufort Sea waters, pinnipeds have previously been 
exposed to seismic noise, and may not react to it, after initial 
exposure.

Numbers of Marine Mammals Expected To Be Taken

    Based upon calculations provided in their application, BPXA 
estimates that the following numbers of marine mammals may be subject 
to Level B harassment, as defined in 50 CFR 216.3:

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                                                                             Harassment takes in 1997           
               Species                      Population size     ------------------------------------------------
                                                                         Possible                Probable       
----------------------------------------------------------------------------------------------------------------
Bowhead..............................  8,000...................  400                      200                   
Gray whale...........................  23,000..................  <10                      0                     
Belukha..............................  41,610..................  250                      150                   
Ringed seal..........................  1-1.5 million...........  400                      <400                  
Spotted seal.........................  >200,000................  10                       5                     
Bearded seal.........................  >300,000................  50                       30                    
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Effects of Seismic Noise and Other Activities on Subsistence Needs

    The disturbance and potential displacement of marine mammals by 
sounds from seismic activities is the principle concern related to 
subsistence use of the area. The harvest of marine mammals (mainly 
bowhead whales, ringed seals, and bearded seals) is central to the 
culture and subsistence economies of the coastal North Slope 
communities (BPXA 1997). In particular, if migrating bowhead whales are 
displaced farther offshore by elevated noise levels, this could make 
harvest of these whales more difficult and dangerous for hunters. The 
harvest could also be affected if bowheads are more skittish when 
exposed to seismic noise (BPXA 1997).
    Nuiqsut is the community closest to the area of the proposed 
activity, and only harvests bowhead whales during the fall whaling 
season. Nuiqsut whalers typically take zero to three whales each season 
(four in 1995; two in 1996), with a trend toward larger harvests in the 
most recent years (BPXA 1997). Nuiqsut whalers concentrate their 
efforts on areas north and east of Cross Island, generally in water 
depths greater than 65 ft (20 m). Cross Island is the principle field 
camp location for Nuiqsut whalers and is located within the general 
area of the proposed seismic area. Thus, the possibility and timing of 
potential seismic operations in the Cross Island area requires BPXA to 
provide NMFS with a Plan of Cooperation with North Slope residents 
(also called the Communications and Avoidance Agreement) to avoid any 
unmitigable adverse impact on subsistence needs.
    Whalers from the village of Kaktovik search for whales east, north 
and west of the village. Kaktovik is located 45 mi (72 km) east of the 
easternmost end of the planned seismic exploration area. The 
westernmost reported harvest location was about 13 mi (21 km) west of 
Kaktovik, near 70 deg.10' N, 144 deg.W. That site is about 32 mi (51 
km) east of the closest part of the primary seismic exploration area 
(BPXA 1997). However, it should be noted that the eastern portion of 
the geographic area noted by BPXA for the authorization extends 
considerably closer to this harvest area.
    Whalers from the village of Barrow search for bowhead whales much 
further from the planned seismic area, >125 mi (>200 km) west (BPXA 
1997).
    The location of the proposed seismic activity is south of the main 
westward migration route of bowhead whales. BPXA (1997) believes that 
although

[[Page 19556]]

whales may be able to hear the sounds emitted by the seismic array out 
to a distance of 30 mi (50 km) or more, it is unlikely that changes in 
migration route will occur at distances of >15 miles (>25 km).
    It is recognized that it is difficult to determine the maximum 
distance at which reactions occur (Moore and Clark 1992), although 
whalers believe that some migrating bowheads are deflected by seismic 
operations at distances greater than those documented by scientific 
studies done to date. As a result, BPXA is developing a Communications 
and Avoidance Agreement with the whalers (see BPXA 1997) to reduce any 
potential interference with the hunt. Also, it is believed that the 
monitoring plan proposed by BPXA (LGL and Greeneridge 1997) will 
provide information that will help resolve uncertainties about the 
effects of seismic exploration on the accessibility of bowheads to 
hunters.
    In addition, while seismic exploration in the Northstar Unit has 
some potential to influence subsistence seal hunting activities, the 
peak season for seal hunting is during the winter months when the 
harvest consists almost exclusively of ringed seals (BPXA 1997). In 
summer, boat crews hunt ringed, spotted and bearded seals (BPXA 1997). 
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 (BPXA 1997). 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 (BPXA 
1997).

Mitigation

    BPXA proposes to continue the mitigation program carried out in 
1996. BPXA plans to use biological observers to monitor marine mammal 
presence in the vicinity of the seismic array. To avoid the potential 
for serious injury to marine mammals, BPXA will power down the seismic 
source if pinnipeds are sighted:
    (a) within 260 m (853 ft) of an array of >720 in3 and 
1,320 in3 at 2.5 m (8.3 ft) depth;
    (b) within 130 m (426 ft) of that array operating at >2.5 m (8.3 
ft) depth;
    (c) within 130 m (426 ft) of an array of >120 in3 and 
720 in3 operating at 2.5 m (8.3 ft) 
depth;
    (d) within 60 m (197 ft) of that array operating at <2.5 m (8.3 ft) 
depth; and
    (e) within 60 m (197 ft) of a single airgun or an array of 
120 in3.
    BPXA will power down the seismic source if bowhead, gray, or 
belukha whales are sighted:
    (a) within either 1020 m (3346 ft) of an array >720 in3 
and 1,320 in3 operating at 2.5m (8.3 
ft) depth; or
    (b) within 640 m (2100 ft) of that array operating at <2.5 m (8.3 
ft) depth or of any smaller airgun source operating at any depth (BPXA 
1997).
    In addition, BPXA proposes to ramp-up the seismic source to 
operating levels at a rate no greater than 6 dB/min. If the array 
includes airguns of different sizes, the smallest gun will be fired 
first. Additional guns will be added at intervals appropriate to limit 
the rate of increase in source level to a maximum of 6 dB/min.

Monitoring

    As part of their application BPXA has provided a monitoring plan 
for assessing impacts to marine mammals from seismic surveys in the 
Beaufort Sea (LGL and Greeneridge 1997). 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.
    Preliminarily, BPXA plans to conduct the following.
Vessel-based Visual Monitoring
    A minimum of two biologist-observers aboard each seismic vessel 
will search for and observe marine mammals whenever seismic operations 
are in progress, and for at least 30 minutes prior to planned start of 
shooting. These observers will scan the area immediately around the 
vessels with reticulated binoculars during the daytime and with night-
vision equipment during the night (prior to mid-August, there are no 
hours of darkness). Individual watches will normally be limited to no 
more than 4 consecutive hours. When mammals are detected within a 
safety zone designated to prevent injury to the animals (see above), 
the geophysical crew leader will be notified so that shutdown 
procedures can be implemented immediately.
Aerial Surveys
    From September 1, 1997, until the seismic program ends, aerial 
surveys will be conducted daily, weather permitting. The primary 
objective will be to document the occurrence, distribution, and 
movements of bowhead and belukha 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 for assessing the 
possibility that seismic operations affect the accessibility of bowhead 
whales for subsistence hunting. Pinnipeds will be recorded when seen. 
Aerial surveys will be at an altitude of 1,000 ft (300 m) above sea 
level. BPXA proposes to avoid overflights of the Cross Island area 
where whalers from Nuiqsut are based during their fall whale hunt.
    The daily aerial surveys are proposed to cover two grids: A grid of 
12 north-south lines spaced 5 mi (8 km) apart and extending from about 
12.5 mi (20 km) west of the western side of the then-current seismic 
exploration area to 30 mi (50 km) east of its eastern edge, and from 
the barrier islands north to approximately the 100 m (328 ft) depth 
contour;
    A grid of 4 survey lines within the above region, also spaced 5 mi 
(8 km) apart and mid-way between the longer lines, to provide more 
intensive coverage of the area of the seismic operations and immediate 
surrounding waters.

Acoustical Measurements

    The acoustic measurement program proposed for 1997 is designed to 
be a sequel to the program conducted at Northstar in 1996 (see BPXA 
1996a and 1997, LGL and Greeneridge 1996b and 1997 for a description of 
the work proposed). The acoustic measurement program is planned to 
include (1) retrieval of bottom recorders deployed in 1996 and analysis 
of usable data contained in those recorders, (2) boat-based acoustic 
measurements, and (3) OBC-based acoustic measurements. Two differences 
between the 1996 and 1997 programs are that BPXA does not plan to 
deploy sonobuoys during the 1997 aerial surveys, and will not redeploy 
the bottom-mounted recorders (5 of the 10 units remain non-functional 
on the sea bottom).
    The boat-based acoustical measurement program is proposed for a 7-
day period in mid-to late-August 1996. The objectives of this survey 
will be as follows: (a) To measure the levels and other characteristics 
of the horizontally-propagating seismic survey sounds from the type(s) 
of airgun array(s) to be used in 1977 as a function of distance and 
aspect relative to the seismic source vessel(s) and relative to water 
depth.
    (b) To measure the levels and frequency composition of the vessel 
sounds emitted by vessels used regularly during the 1977 program, 
excluding vessels whose sounds were characterized adequately in 1996.
    (c) To obtain additional site-specific ambient noise data, which 
determine signal-to-noise ratios for seismic and

[[Page 19557]]

other acoustic signals at various ranges from their sources.
    New to the acoustic measurement program for 1997 is a plan to test 
the feasibility to use the hydrophones in the OBC to measure received 
levels and characteristics of airgun pulses over a large area (about 
3.3X5.9 km) simultaneously. If practical, this would provide more 
comprehensive data while at the same time reducing the need for labor-
intensive boat-based acoustic measurements.

Estimates of Marine Mammal Take

    Estimates of takes by harassment will be made through vessel and 
aerial surveys. Preliminarily, BPXA 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) above when no monitoring observations were possible; and (d) 
bowheads displaced seaward from the main migration corridor.

Reporting

    BPXA will provide an initial report on 1997 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 BPXA within 20 working 
days of receipt of the document from the contractor, but no later than 
April 30, 1998. 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, NMFS completed an 
informal consultation on the issuance of an incidental harassment 
authorization for this activity on July 15, 1996. A copy of that 
document is available upon request (see ADDRESSES).

National Environmental Policy Act (NEPA)

    In conjunction with the 1996 notice of proposed authorization (61 
FR 26501, May 28, 1996), NMFS released an EA that addressed the 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 to BPXA for the harassment 
of small numbers of several species of marine mammals incidental to 
conducting seismic surveys during the open water season in the 
Northstar Unit and nearby waters 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. A copy of the EA is available 
upon request (see ADDRESSES).

Conclusions

    NMFS has preliminarily determined that the short-term impact of 
conducting seismic surveys in the Northstar Unit of the Beaufort Sea 
will result, at worst, in a temporary modification in behavior by 
certain species of cetaceans. While behavioral modifications may be 
made by these species of cetaceans to avoid the resultant noise, this 
behavioral change is expected to have a negligible impact on the 
animals.
    As 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 incorporation of the mitigation measures mentioned above. 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. After August 31, 1997, BPXA will initiate aerial survey 
flights for bowhead whale assessments. 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 BPXA and subsistence users.
    Also, while summer seismic exploration in the Northstar Unit 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 (west and 
inshore of Northstar), and (3) the zone of influence by seismic sources 
on belukha and seals is fairly small, NMFS believes the Northstar 
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 incidental harassment authorization for 
the 1997 Beaufort Sea open water season for a seismic survey in and 
near the Northstar Unit provided the above 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, gray 
whales, and possibly belukha whales, bearded seals, and largha seals; 
will have a negligible impact on these marine mammal stocks; and will 
not have an unmitigable adverse impact on the availability of these 
stocks for subsistence uses.

Information Solicited

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

    Dated: April 16, 1997.
Hilda Diaz-Soltero,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 97-10254 Filed 4-21-97; 8:45 am]
BILLING CODE 3510-22-P