[Federal Register Volume 61, Number 103 (Tuesday, May 28, 1996)]
[Notices]
[Pages 26501-26504]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-13287]



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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[I.D. 050196A]


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 (BPX) for authorization 
to take small numbers of marine mammals by harassment incidental to 
conducting seismic surveys in 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 BPX to 
incidentally take, by harassment, small numbers of bowhead whales and 
other marine mammals in the above mentioned area during the open water 
period of 1996.

DATES: Comments and information must be received no later than June 27, 
1996.

ADDRESSES: Comments on the application should be addressed to Chief, 
Marine Mammal Division, Office of Protected Resources, National Marine 
Fisheries Service, 1315 East-West Highway, Silver Spring, MD 20910-
3225. A copy of the application, an environmental assessment (EA), and 
a list of references used in this document may be obtained by writing 
to this address, by telephoning one of the contacts listed below or by 
leaving a voice mail request at (301) 713-4070.

FOR FURTHER INFORMATION CONTACT: Kenneth R. Hollingshead, Office of 
Protected Resources, NMFS, (301) 713-2055, Ron Morris, 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 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 18, 1996, NMFS received an application from BPX 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 within the Northstar Unit, located in the Beaufort 
Sea in U.S. waters. The survey is expected to take place between 
approximately July 20 and October 20, 1996. A detailed description of 
the work planned is contained in the application (BPX 1996) 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 (SAIC 1996) 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 glacialis), gray whales 
(Eschrichtius robustus), belukha (Delphinapterus leucas), ringed seals 
(Phoca hispida), spotted seals (Phoca largha) and bearded seals 
(Erignathus barbatus). Descriptions on the biology and distribution of 
these species, and others, can be found in several other documents (BPX 
1996, 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. Vessel 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 could 
also lead to non-acoustic effects involving visual or other cues. These 
surveys are accomplished by transmitting sound waves into the earth, 
which are reflected

[[Page 26502]]

off subsurface formations and recorded with detectors in the water 
column. A typical marine seismic source is an airgun array, which 
releases compressed air into the water creating an acoustical energy 
pulse that is directed downwards toward the seabed. Hydrophones spaced 
along a streamer cable just below the surface of the water receive the 
reflected energy from the subsurface formations and transmit data to 
the seismic vessel. Onboard the vessel, the signals are amplified, 
digitized, and recorded on magnetic tape.
    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 (BPX 1996). An incidental harassment take is 
presumed to occur when marine mammals in the vicinity of the seismic 
source (or other vessels) 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 (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 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).
    Hearing damage is not expected to occur during the project. It is 
not known whether a marine mammal very close to an air gun 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). 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 (BPX 1996). 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-dive-
respiration 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 (BPX 1996).

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 (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 (BPX 1996).
    Within a 3.7-60 mile (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).

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.

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 
air gun arrays is concentrated) is poor (125 dB re 1 Pa @ 1 m) 
or more depending upon frequency (Johnson et al. 1989 (as referenced in 
BPX 1996), 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 3 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 an 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, 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

[[Page 26503]]

exposed to seismic noise, and may not react to it, after initial 
exposure.
    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 (BPX 1996). Displacement of migrating marine mammals 
farther offshore due to behavioral changes resulting from elevated 
noise levels could potentially make harvest of these species more 
difficult.
    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, with a trend toward larger harvests in the most recent years 
(BPX 1996). Nuiqsut whalers concentrate their efforts on areas north 
and east of the Northstar Unit, generally in water depths greater than 
65 ft (20 m). Cross Island, located 13 miles (20 km) east of the 
eastern edge of the primary area of proposed activity, is the principle 
field camp location for Nuiqsut whalers. Thus, most bowhead whales will 
not enter the ensonified area until they have passed through the area 
used by Nuiqsut whalers (BPX 1996).
    The location of the proposed seismic activity is to the south of 
the main westward migration route of bowhead whales. BPX believes that 
although whales may be able to hear the sounds emitted by the seismic 
array out to a distance of 30 miles (50 km) or more, it is unlikely 
that changes in migration route will occur at distances of >15 miles 
(>25 km). As discussed above, scientific studies have shown obvious 
avoidance reactions at distances up to 3.7-5 miles (6-8 km), with one 
probable case of avoidance at 15 miles (24 km)(Richardson et al. 1986, 
Koski and Johnson 1987, Ljungblad et al. 1988). However, other bowheads 
>3.7 miles (>6 km) from shallow-water seismic operations showed no 
obvious avoidance (BPX 1996).
    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, BPX is developing a Communications and Avoidance 
Agreement with the whalers (see BPX 1996) to reduce any potential 
interference with the hunt. Also, it is believed that the monitoring 
plan proposed by BPX (LGL 1996) 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 (BPX 1996). In 
summer, boat crews hunt ringed, spotted and bearded seals (BPX 1996). 
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 (BPX 1996). In this area, during summer, sealing occurs by boat 
when hunters apparently concentrate on bearded seals (BPX 1996).

Mitigation

    BPX proposes 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, BPX will power down the seismic 
source if pinnipeds are sighted within 500 ft (150 m) of the source or 
if cetaceans are sighted within 2,130 ft (650 m) of the source. At 500 
ft (150 m), the average pulse levels will be less than 190 dB (re 1 
Pa @ 1 m). At 2,130 ft (650 m), the average pulse level is 
expected to be about 180 dB (re 1 Pa @ 1 m), based on the 
expected characteristics of the air gun array to be used in this 
program, and on site-specific propagation loss data (from Miles et al. 
1987).
    In addition, NMFS proposes to require BPX to ramp-up the seismic 
source from a level less than, or equal to, 160 dB to its operating 
level immediately preceding transmissions at a rate not exceeding 6 dB/
min and to power-down the array to a level no greater than 160 dB 
whenever marine mammals enter their respective safety zone. NMFS will 
recommend ramp-up be accomplished through software designed to fire a 
specified sequence of guns operating at a designated pressure until the 
full array of guns are firing at peak operating pressure.

Monitoring

    As part of their application, BPX provided a preliminary monitoring 
plan for assessing impacts to marine mammals from seismic surveys in 
the Beaufort Sea (LGL 1996). 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, BPX plans to conduct the following:

(1) Vessel-based Visual Monitoring

    Two biologist-observers aboard the seismic vessel will search for 
and observe marine mammals whenever seismic operations are in progress, 
and immediately preceding the start of shooting. These observers will 
scan the area immediately around the vessels with binoculars during the 
daytime and with night vision equipment during the night. When mammals 
are detected within a safety zone designated to prevent injury to the 
animals, the geophysical crew leader will be notified so that shutdown 
procedures can be implemented.

(2) Aerial Surveys

    From September 1, 1996 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, 
and sonobuoys will be dropped to document ambient noise and 
characteristics of seismic noise near whale sightings. Aerial surveys 
will be at an altitude of 1,000 ft (300 m) above sea level. It is 
tentatively proposed to avoid direct 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) A grid of 12 north-south lines spaced 8 km (5 miles) apart and 
extending to about 30 mi (50 km) offshore, 30 mi (50 km) east, and 12.5 
mi (20 km) west of the Northstar area;
    (b) A grid of 8 north-south 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.

(3) Acoustical Measurements

    A boat-based acoustical measurement program is proposed for a 10-
day period in mid- to late-August 1996. The objectives of this survey 
will be as follows:

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    (a) To measure the levels and other characteristics of the 
horizontally-propagating seismic survey sounds as a function of 
distance and aspect relative to BPX's seismic source vessel.
    (b) To measure acoustic transmission loss vs. frequency, distance, 
and propagation direction in and near the Northstar Unit, based on 
transmission and reception of standardized acoustic signals having a 
source level of about 165 dB re 1 Pa @ 1 m. Transmissions will 
not be done if bowheads are seen within 2,130 ft (650 m) of the seismic 
array.
    (c) 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.
    In addition, data on ambient noise and on characteristics of 
seismic pulses will be obtained from sonobuoys dropped and monitored 
from the survey aircraft after September 1, 1996.
    For a more detailed description of planned monitoring activities, 
please refer to the application and supporting document (LGL 1996).

Reporting

    BPX will provide an initial report 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 BPX within 20 working 
days of receipt of the document from the contractor, but no later than 
April 30, 1996. 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 has begun 
consultation on the proposed issuance of this authorization. 
Consultation will be concluded upon completion of the comment period 
and consideration of those comments in the final determination on 
issuance of an authorization.

National Environmental Policy Act

    In conjunction with this notice, NMFS has released an EA that 
addresses the impacts on the human environment from issuance of the 
authorization and the alternatives to the proposed action. 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.
    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 September 1, 1996, BPX 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 BPX 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 1996 Beaufort Sea open water season for a seismic survey within 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: May 17, 1996.
Patricia A. Montanio,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 96-13287 Filed 5-23-96; 10:02 am]
BILLING CODE 3510-22-F