[Federal Register Volume 63, Number 87 (Wednesday, May 6, 1998)]
[Notices]
[Pages 25015-25020]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-12001]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration
[I.D. 041598A]


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 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 1998.

DATES: Comments and information must be received no later than June 5, 
1998.

ADDRESSES: Comments on the application should be addressed to

[[Page 25016]]

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, a 1996 environmental assessment (EA), the 
1997 informal section 7 consultation, BPXA's 1997 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 here.

FOR FURTHER INFORMATION CONTACT: Kenneth R. Hollingshead, (301) 713-
2055, Brad Smith, (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) 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 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 26, 1998, NMFS received an application from BPXA 
requesting a 1-year renewal of its 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 Beaufort 
Sea between Harrison Bay and Camden Bay/Flaxman Island, AK. Weather 
permitting, the survey is expected to take place between approximately 
July 1 and October 20, 1998. A detailed description of the work 
proposed for 1998 is contained in the application (BPXA, 1998) 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). This information is incorporated by 
reference 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 of others can be found in several other documents 
(BPXA, 1996b, 1998; Lentfer, 1988; MMS, 1992, 1996; Small and DeMaster, 
1995; Hill et al., 1997). 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 will provide a secondary 
source of noise. The physical presence of vessels and aircraft could 
also lead to non-acoustic effects 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. OBC surveys involve dropping cables from a 
ship to the ocean bottom, forming a patch consisting of 6 cables 5.9 
kilometers (km) (3.7 mi) long, separated 660 m (2,165 ft) from each 
other. Sensors (hydrophones) are attached to the cables. 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 downward toward the seabed. Normally, 27 seismic lines are 
run for each patch, covering an area 7.3 km by 8.6 km (4.5 mi by 5.3 
mi), centered over the patch.
    After sufficient data have 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 the sizes 
of the various airguns, and for numbers of vessels planned for this 
survey, please refer to the application (BPXA, 1998).
    Depending upon ambient 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 (BPXA, 1998). 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 bowhead whales to behaviorally 
respond within a distance of several kilometers (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 second in duration every 6 to 12 seconds) 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, 1998).
    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 later in this 
document) 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, 1998). The 
levels, frequencies, and types of noise that will elicit a response 
vary between

[[Page 25017]]

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 (BPXA, 1998).

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 7.5 km (4.5 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 (BPXA, 1996a, 1996b, 1998).
    Within a 6-99 km (3.7-60 mi) 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 (BPXA, 1996a, 1996b). 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 preclude meaningful interpretation 
(BPXA, 1998).
    Inupiat whalers believe that migrating bowheads are sometimes 
displaced at distances considerably greater than 6 to 8 km (3.7 to 5.0 
mi)(Rexford, 1996). Scientific studies done to date have limitations as 
discussed in part by Moore and Clark (1992) and MMS (1996). It is 
possible that, when additional data are available, it will be 
demonstrated that bowheads sometimes do avoid seismic vessels at 
distances beyond 6 to 8 km (3.7 to 5.0 mi). Also, whalers have 
mentioned that bowheads sometimes seem more ``skittish'' and more 
difficult to approach when seismic exploration is underway in the area. 
This ``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 
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 approximately 50 percent showed avoidance 
when the average received pulse level was 170 dB (re 1 Pa @ 1 
m). 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.

Belukha

    The belukha is the only species of toothed whale (Odontoceti) 
expected to be encountered in the Beaufort Sea. Because their 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 et 
al., 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 distances of 100 km 
(Richardson and Wursig, 1997). The reaction distance for belukha, 
although presently unknown, is expected to be less than that for 
bowheads, given the presumed poorer sensitivity of belukhas than that 
of bowheads for low-frequency sounds (BPXA, 1998).

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 of 80-100 dB over its threshold is 
needed in order to cause annoyance and 130 dB for injury (pain), as is 
the current thought based upon human studies (Advanced Research 
Projects Agency and NMFS, 1995), 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, pinnipeds would likely 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/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.

Other Effects

    For a discussion on the anticipated effects of ships, boats, 
aircraft, and smaller acoustic devices, such as single airguns, 
sparkers, sub-bottom profilers, side-scan sonar, and bathymetric 
sounders, on marine mammals and their food sources, please refer to the 
application (BPXA, 1998). Information on these effects is incorporated 
in this document by reference (see BPXA, 1998). Numbers of Marine 
Mammals Expected to be Taken

[[Page 25018]]

    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 
                                                                                                   1998         
                   Species                                  Population size              -----------------------
                                                                                           Possible    Probable 
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Bowhead......................................  8,000....................................         800        <400
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 are the principle concerns 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, 1998). 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 (BPXA, 1998).
    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 zero to four 
whales each season (BPXA, 1998). 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 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 (also called the Communications 
and Avoidance Agreement) with North Slope Borough residents 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 60 mi (38 km) east of the 
easternmost end of the planned 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 (25 mi) east of the closest part of the planned 
seismic exploration area for 1998 (BPXA, 1998).
    Whalers from the village of Barrow search for bowhead whales much 
further from the planned seismic area, >200 km (>125 mi) west (BPXA, 
1998).
    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. BPXA (1998) believes that, although whales may be able to 
hear the sounds emitted by the seismic array out to a distance of 50 km 
(30 mi) or more, it is unlikely that changes in migration route will 
occur at distances of >25 km (>15 mi). Alternatively, whalers believe 
that bowheads begin to divert from their normal migration path more 
than 48 km (35 mi) away (MMS, 1996).
    It is recognized that it is difficult to determine the maximum 
distance at which reactions occur (Moore and Clark, 1992). As a result, 
BPXA is developing a Communications and Avoidance Agreement with the 
whalers to reduce potential interference with the hunt. Also, it is 
believed that the monitoring plan proposed by BPXA (LGL Ltd. and 
Greeneridge Sciences Inc, 1998) will provide information that will help 
resolve uncertainties about the effects of seismic exploration on the 
accessibility of bowheads to hunters.
    While seismic exploration 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, 1998). In summer, boat crews hunt 
ringed, spotted and bearded seals (BPXA, 1998). 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, 
1998). 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, 1998).

Mitigation

    BPXA proposes to continue the mitigation program carried out in 
1996 and 1997. 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 within the area delineated 
by the 190 dB isopleth or:
    (1) within 60 m (197 ft) of a single airgun or an array of 
60 in3.
    (2) within 110 m (361 ft) of an array >60 in3 and 
720 in3 at <2.5 m (8.3 ft) depth;
    (3) within 190 m (623 ft) of an array >60 in3 and 
720 in3 operating at 2.5 m (8.3 ft) 
depth;
    (4) within 150 m (492 ft) of an array >720 in3 and 
840 in3 operating at <2.5 m (8.3 ft) depth;
    (5) within 250 m (820 ft) of an array >720 in3 and 
840 in operating at 2.5 m (8.3 ft) 
depth;
    (6) within 260 m (853 ft) of an array >840 in\3\ operating at 
2.5 m (8.3 ft) depth; and
    (7) within 130 m (426 ft) of an array >840 in\3\ operating at >2.5 
m (8.3 ft) depth.
    BPXA will power down the seismic source if bowhead, gray, or 
belukha whales are sighted within the area delineated by the 180 dB 
isopleth or:
    (1) within 160 m (525 ft) of a single airgun or an array of 
60 in\3\;
    (2) within 600 m (1,928 ft) of an array >60 in\3\ and 
720 in\3\ at >2.5 m (8.3 ft) depth;
    (3) within 800 m (2,625 ft) of an array >60 in\3\ and 
720 in\3\ operating at 2.5 m (8.3 ft) depth;
    (4) within 700 m (2,298 ft) of an array >720 in\3\ and 
840 in\3\ operating at <2.5 m (8.3 ft) depth;
    (5) within 900 m (2,953 ft) of an array >720 in\3\ and 
840 in\3\ operating at 2.5 m (8.3 ft) depth;
    (6) within 1020 m (3,346 ft) of an array >840 in\3\ operating at 
2.5 m (8.3 ft) depth; and

[[Page 25019]]

    (7) within 640 m (2,100 ft) of an array >840 in\3\ operating at 
>2.5 m (8.3 ft) depth.
    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 its application, BPXA provided a monitoring plan for 
assessing impacts to marine mammals from seismic surveys in the 
Beaufort Sea. This monitoring plan is described in detail in BPXA 
(1998) and LGL Ltd. and Greeneridge Sciences Inc. (1998). 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. 1
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    \1\ Because individual watches will normally be limited to no 
more than 4 consecutive hours, NMFS believes that no seismic vessel 
(including those conducting shallow-hazards surveys) will be able to 
operate with fewer than two observers, unless surveys are shorter 
than 4 consecutive hours.
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    When mammals are detected within a 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

    From September 1, 1998, until 3 days after 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 to assess 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 300 m (1,000 ft) above sea 
level. BPXA proposes to avoid overflights of the Cross Island area 
where whalers from Nuiqsut are based during their fall whale hunt.
    Consistent with the 1996 and 1997 aerial surveys, the daily aerial 
surveys are proposed to cover two grids: (1) A grid of 12 north-south 
lines spaced 8 km (5 mi) apart and extending from about 20 km (12.5 mi) 
west of the western side of the then-current seismic exploration area 
to 50 km (30 mi) east of its eastern edge, and from the barrier islands 
north to approximately the 100 m (328 ft) depth contour; and (2) a grid 
of 4 survey lines within the above region, also spaced 8 km (5 mi) 
apart and mid-way between the longer lines, to provide more intensive 
coverage of the area of the seismic operations and immediate 
surrounding waters.
    When the seismic program is relocated east or west along the coast 
during the 1998 season, both survey grids will be relocated a 
corresponding distance along the coast. Information on the survey 
program can be found in BPXA (1998) and in LGL Ltd. and Greeneridge 
Sciences Inc. (1998), which are incorporated herein by reference.

Acoustical Measurements

    The acoustic measurement program proposed for 1998 is designed to 
be a sequel to the program conducted in 1996 and 1997 (see BPXA, 1996a, 
1997, and 1998; LGL Ltd. and Greeneridge Sciences Inc., 1996, 1997, and 
1998). The acoustic measurement program is planned to include (1) 
retrieval of autonomous seafloor acoustic recorders (ASARs) deployed 
and not recovered in 1997 and analysis of usable data contained in 
those recorders, (2) deployment of ASARs during the 1998 seismic 
program to provide continuous acoustic data for extended periods, (3) 
boat-based acoustic measurements, (4) OBC-based acoustic measurements, 
and (5) use of air-dropped sonobuoys.
    The boat-based acoustical measurement program is proposed for a 7-
day period in August 1998. The objectives of this survey will be as 
follows: (1) 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 1998 as a function of distance and aspect 
relative to the seismic source vessel(s) and to water depth.
    (2) To measure the levels and frequency composition of the vessel 
sounds emitted by vessels used regularly during the 1998 program, 
excluding vessels whose sounds were characterized adequately in 
previous years.
    (3) To obtain additional site-specific ambient noise data, which 
determine signal-to-noise ratios for seismic and other acoustic signals 
at various ranges from their sources. This aspect of the monitoring is 
described in more detail in BPXA (1998) and LGL Ltd. and Greeneridge 
Sciences Inc. (1998).

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 1998 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, 1999. 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 incidental harassment 
authorization for this activity on June 26, 1997. A copy of that 
document is available upon request (see ADDRESSES). If an authorization 
to incidentally harass listed marine mammals is issued under the MMPA, 
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,

[[Page 25020]]

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 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).
    This year's activity is a continuation of the seismic work 
conducted in 1996 and 1997. For BPXA's 1998 application, NMFS has 
conducted a review of the impacts expected from the issuance of an 
Incidental Harassment Authorization in comparison to those impacts 
evaluated in 1996. As assessed in detail in this document, NMFS has 
preliminarily 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. Because the activity is 
substantially the same as the one conducted in 1996 and no new impacts 
on the environment have been identified, a new EA is not warranted.

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 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.
    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 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. After August 31, 1998, 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 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 belukha and seals is fairly 
small, NMFS believes that BPXA'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 incidental harassment authorization for 
the 1998 Beaufort Sea open water season for a seismic survey 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; would have 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: May 1, 1998.
Patricia A. Montanio,
Deputy Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 98-12001 Filed 5-5-98; 8:45 am]
BILLING CODE 3510-22-P