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

DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[I.D. 040799A]

Small Takes of Marine Mammals Incidental to Specified Activities;

Offshore Seismic Activities in the Beaufort Sea

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and

Atmospheric Administration (NOAA), Commerce.

ACTION: Notice of receipt of application and proposed authorization for

a small take exemption; request for comments.

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SUMMARY: NMFS has received a request from Western Geophysical/Western

Atlas International of Houston, Texas (Western Geophysical) for an

authorization to take small numbers of marine mammals by harassment

incidental to conducting seismic surveys in the Beaufort Sea in state

and Federal waters. Under the Marine Mammal Protection Act (MMPA), NMFS

is requesting comments on its proposal to authorize Western Geophysical

to incidentally take, by harassment, small numbers of bowhead whales

and other marine mammals in the above mentioned areas during the open

water period of 1999.

DATES: Comments and information must be received no later than June 28,

1999.

ADDRESSES: Comments on the application should be addressed to Donna

Wieting, Acting Chief, Marine Mammal Division, Office of Protected

Resources, NMFS, 1315 East-West Highway, Silver Spring, MD 20910-3225.

A copy of the application, a list of references used in this document,

and/or an environmental assessment (EA) 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

Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.)

direct the Secretary of Commerce to allow, upon request, the

incidental, but not intentional taking of 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 (IHAs) under section 101(a)(5)(D) of the MMPA

for activities in Arctic waters. For additional information on the

procedures to be followed for this authorization, please refer to that

document.

Summary of Request

On March 24, 1999, NMFS received an application from Western

Geophysical requesting an authorization for the harassment of small

numbers of several species of marine mammals incidental to conducting

seismic surveys during the open water season in the Beaufort Sea

between western Camden Bay and Harrison Bay off Alaska.

Weather permitting, the survey is expected to take place between

approximately July 1 and mid- to late-October, 1999. However, only a

small portion of the area between western Camden Bay and

Harrison Bay will be surveyed this year. A detailed

description of the work proposed for 1999 is contained in the

application (Western Geophysical, 1999) 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 or in other documents (Corps of Engineers, 1999; Minerals

Management Service (MMS), 1992, 1996). The relevant information

contained in these documents is incorporated by citation into this

section 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), beluga (Delphinapterus leucas), ringed seals

(Phoca hispida), spotted seals (Phoca largha) and bearded seals

(Erignathus barbatus). Descriptions of the biology and distribution of

these species and of others can be found in the previously referenced

EA, the 1999 application from Western Geophysical, the annual

monitoring reports for seismic surveys in the Beaufort Sea (LGL Ltd.

and Greeneridge Sciences Inc, 1997, 1998, and 1999a) and several other

documents (Corps of Engineers, 1999; Lentfer, 1988; MMS, 1992, 1996;

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 potential

secondary source of noise. The physical presence of vessels and

aircraft could also lead to non-acoustic effects on marine mammals

involving visual or other cues.

Seismic surveys are used to obtain data about formations several

thousands of feet deep. The proposed seismic operation is an ocean

bottom cable (OBC) survey. For this activity, OBC surveys involve

dropping cables from a ship to the ocean bottom, forming a

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patch consisting of 4 parallel cables 8.9 kilometers (km) (4.8 nautical

miles (nm)) long, separated by approximately 600 meters (m) (1,968 feet

(ft)) from each other. Hydrophones and geophones, attached to the

cables, are used to detect seismic energy reflected back from

underground rock strata. The source of this energy is a submerged

acoustic source, called a seismic airgun array, that releases

compressed air into the water, creating an acoustical energy pulse that

is directed downward toward the seabed. The source level planned for

this project - a maximum of 247 dB re 1 Pa-m or 22.3 bar-

meters (zero to peak), or a maximum of 252 dB re 1 Pa-m or 39

bar-meters (peak-to-peak) - will be from an airgun array

with a air discharge volume of 1,210 in3. This compares to

the 1,500 in3 array used on Western Geophysical's primary

source vessel in 1998 and will be the only airgun array used by Western

Geophysical in the Beaufort Sea this year.

It is anticipated that 34 seismic lines will be run for each patch,

covering an area 5.0 km by 15.7 km (2.7 nm by 8.1 nm), centered over

the patch. Source lines for one patch will overlap with those for

adjacent patches.

After sufficient data have been recorded to allow accurate mapping

of the rock strata, the cables are lifted onto the deck of a cable-

retrieval vessel, moved to a new location (ranging from several hundred

to a few thousand feet away), and placed onto the seabed again. For a

more detailed description of the seismic operation, please refer to the

1999 application from Western Geophysical.

Depending upon ambient noise conditions and the sensitivity of the

receptor, underwater sounds produced by open water seismic operations

may be detectable a substantial distance away from the activity. Any

sound that is detectable is (at least in theory) capable of eliciting a

disturbance reaction by a marine mammal or of masking a signal of

comparable frequency (Western Geophysical, 1999). An incidental

harassment take is presumed to occur when marine mammals in the

vicinity of the seismic source, the seismic vessel, other vessels, or

aircraft react to the generated sounds or to visual cues.

Seismic pulses are known to cause strong avoidance reactions by

many of the bowhead whales occurring within a distance of several

kilometers and may sometimes cause avoidance or other changes in

bowhead behavior at considerably greater distances (Richardson et al.,

1995; Rexford, 1996; MMS, 1997). Results from the 1996-1998 BP and

Western Geophysical seismic program monitoring indicate that most

bowheads avoided an area within about 20 km (10.8 nm) of nearshore

seismic operations (Miller et al., 1998, 1999). It is also possible

that seismic pulses may disturb some other marine mammal species

occurring in the area.

Although some limited masking of low-frequency sounds (e.g., whale

calls) is a possibility, the intermittent nature of seismic source

pulses (1 second in duration every 16 to 24 seconds) 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 (LGL and Greeneridge, 1997, 1998, 1999a; Richardson et

al., 1986). Masking effects are expected to be absent in the case of

belugas, given that sounds important to them are predominantly at much

higher frequencies than are airgun sounds (Western Geophysical, 1999).

Hearing damage is not expected to occur during the project. It is

not positively known whether the hearing systems of marine mammals very

close to an airgun might be subject to temporary or permanent hearing

impairment (Richardson et al., 1995). However, planned monitoring and

mitigation measures (described later in this document) are designed to

avoid sudden onsets of seismic pulses at full power, to detect marine

mammals occurring near the array, and to avoid exposing them to sound

pulses that have any possibility of causing hearing impairment.

When the received levels of noise exceed some behavioral reaction

threshold, cetaceans will show disturbance reactions. The levels,

frequencies, and types of noise that will elicit a response vary

between and within species, individuals, locations, and seasons.

Behavioral changes may be subtle alterations in surface, respiration,

and dive cycles. More conspicuous responses include changes in activity

or aerial displays, movement away from the sound source, or complete

avoidance of the area. The reaction threshold and degree of response

are related to the activity of the animal at the time of the

disturbance. Whales engaged in active behaviors, such as feeding,

socializing, or mating, are less likely than resting animals to show

overt behavioral reactions, unless the disturbance is directly

threatening.

Bowhead Whales

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. In studies prior to 1996,

bowheads exposed to seismic pulses from vessels more than 7.5 km (4.0

nm) away rarely showed observable avoidance of the vessel, but their

surface, respiration, and dive cycles appeared altered in a manner

similar to that observed in whales exposed at a closer distance

(Western Geophysical, 1999).

Within a 6- to 99-km (3.2 to 53.5 nm) 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 (Western Geophysical,

1999). However, in three studies of bowhead whales and one of gray

whales, surfacing-dive cycles have been unusually rapid in the presence

of seimic noise, with fewer breaths per surfacing and longer intervals

between breaths (Richardson et al., 1986; Koski and Johnson, 1987;

Ljungblad et al., 1988; Malme et al., 1988). This pattern of subtle

effects was evident among bowheads 6 km to at least 73 km (3.2 to 39

nm) from seismic vessels. However, in the pre-1996 studies, active

avoidance usually was not apparent unless the seismic vessel was closer

than about 6 to 8 km (3.2 to 4.3 nm)(Western Geophysical, 1999).

Inupiat whalers believe that migrating bowheads are sometimes

displaced at distances considerably greater than 6 to 8 km (3.3 to 4.3

nm)(Rexford, 1996). Also, whalers have mentioned that bowheads

sometimes seem more ``skittish'' and more difficult to approach when

seismic exploration is underway in the area. It is possible that, when

additional data are available and analyzed, it may be demonstrated that

isolated bowheads avoid seismic vessels at distance beyond 20 km (10.8

nm). Also, the ``skittish'' behavior may be related to the observed

subtle changes in the behavior of bowheads exposed to seismic pulses

from distant seismic vessels (Richardson et al., 1986).

Gray Whales

The reactions of gray whales to seismic pulses are similar to those

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

[[Page 28994]]

pulse level was 170 dB (re 1 Pa). By some behavioral measures,

clear effects were evident at average pulse levels of 160+dB; less

consistent results were suspected at levels of 140-160 dB. Recent

research on migrating gray whales showed responses similar to those

observed in the earlier research when the source was moored in the

migration corridor 2 km (1.1 nm) from shore. However, when the source

was placed offshore (4 km (2.2 nm) from shore) of the migration

corridor, the avoidance response was not evident on track plots (Tyack

and Clark. 1998).

Beluga

The beluga is the only species of toothed whale (Odontoceti)

expected to be encountered in the Beaufort Sea. 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), beluga are not predicted to be strongly influenced by

seismic noise. However, because of the high source levels of seismic

pulses, airgun sounds sometimes may be audible to beluga at distances

of 100 km (54 nm)(Richardson and Wursig, 1997). The reaction distance

for beluga, although presently unknown, is expected to be less than

that for bowheads, given the presumed poorer sensitivity of belugas

than that of bowheads for low-frequency sounds (Western Geophysical,

1999).

Ringed, Largha and Bearded Seals

No detailed studies of reactions by seals to noise from open water

seismic exploration have been published (Richardson et al., 1995).

However, there are some data on the reactions of seals to various types

of impulsive sounds (LGL and Greeneridge, 1997, 1998, 1999a; J. Parsons

as quoted in Greene, et al. 1985; Anon., 1975; Mate and Harvey, 1985).

These studies indicate that ice seals typically either tolerate or

habituate to seismic noise produced from open water sources.

Underwater audiograms have been obtained using behavioral methods

for three species of phocinid seals, ringed, harbor, and harp seals

(Pagophilus groenlandicus). These audiograms were reviewed in

Richardson et al. (1995) and Kastak and Schusterman (1998). Below 30-50

kHz, the hearing threshold of phocinids is essentially flat down to at

least 1 kHz and ranges between 60 and 85 dB (re 1 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, 1998).

While no detailed studies of reactions of seals from open-water

seismic exploration have been published (Richardson et al., 1991,

1995), some data are available on the reactions of seals to various

types of impulsive sounds (see LGL and Greeneridge, 1997, 1998, 1999a;

Thompson et al. 1998). These references indicate that it is unlikely

that pinnipeds would be harassed or injured by low frequency sounds

from a seismic source unless they were within relatively close

proximity of the seismic array. For permanent injury, pinnipeds would

likely need to remain in the high-noise field for extended periods of

time. Existing evidence also suggests that, while seals may be capable

of hearing sounds from seismic arrays, they appear to tolerate intense

pulsatile sounds without known effect once they learn that there is no

danger associated with the noise (see, for example, NMFS/Washington

Department of Wildlife, 1995). In addition, they will apparently not

abandon feeding or breeding areas due to exposure to these noise

sources (Richardson et al., 1991) and may habituate to certain noises

over time. Since seismic work is fairly common in Beaufort Sea waters,

pinnipeds have been previously exposed to seismic noise and may not

react to it after initial exposure.

For a discussion on the anticipated effects of ships, boats, and

aircraft, on marine mammals and their food sources, please refer to the

application (Western Geophysical, 1999). Information on these effects

is incorporated in this document by citation.

Numbers of Marine Mammals Expected to Be Taken

Western Geophysical estimates that the following numbers of marine

mammals may be subject to Level B harassment, as defined in 50 CFR

216.3:

------------------------------------------------------------------------

Population Harassment Takes in

---------------- 1999

Species ---------------------

Size Possible

Probable

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Bowhead........................... 9,900

160 dB criterion.................. 1,000 200,000 10 300,000 50 o10'N,

144oW (Kaleak, 1996). That site is approximately 40 km (21.6

nm) east of the closest part of Western Geophysical's planned seismic

exploration area for 1999 (Western Geophysical, 1999).

Whalers from the village of Barrow search for bowhead whales much

further from the planned seismic area, >200 km (>108 nm) west (Western

Geophysical, 1999).

The location of the proposed seismic activity is south of the

center of the westward migration route of bowhead whales, but there is

some overlap. Seismic monitoring results from 1996-1998 indicate that

most bowheads avoid the area within about 20 km (11 nm) around the

array when it is operating. In addition, bowheads may be able to hear

the sounds emitted by the seismic array out to a distance of 50 km (27

nm) or more, depending on the ambient noise level and the efficiency of

sound propagation along the path between the seismic vessel and the

whale (Miller et al., 1997. Western Geophysical (1999) believes it is

unlikely that changes in migration route will occur at distances

greater than 25 km (13 nm) from an array of maximum volume of 1,210

in3 operating in water less than 30 m (100 ft) deep.

However, subtle changes in behavior might occur out to longer

distances. Inupiat whalers believe that bowheads begin to divert from

their normal migration path more than 35 miles away (MMS, 1997).

It is recognized that it is difficult to determine the maximum

distance at which reactions occur (Moore and Clark, 1992). As a result,

Western Geophysical will participate in a C&AA with the whalers to

reduce any potential interference with the hunt. Also, it is believed

that the monitoring plan proposed by Western Geophysical (1999; also

see LGL Ltd. and Greeneridge Sciences Inc, 1999b) will provide

information that will help resolve uncertainties about the effects of

seismic exploration on the accessibility of bowheads to hunters.

Many Nuiqsut hunters hunt seals intermittently year-round. However,

during recent years, most seal hunting has been during the early summer

in open water. In summer, boat crews hunt ringed, spotted and bearded

seals. The most important sealing area for Nuiqsut hunters is off the

Colville delta, extending as far west as Fish Creek and as far east as

Pingok Island. This area overlaps with the westernmost portion of the

planned seismic area. In this area, during summer, sealing occurs by

boat when hunters apparently concentrate on bearded seals. However,

these subsistence hunters have not perceived any interference between

recent open-water seismic activities in the Alaskan Beaufort Sea.

Therefore, because Western Geophysical is proposing similar mitigation

and consultation procedures this year, it is unlikely that seismic

activities would have more than a negligible impact on Nuiqsut seal

hunting.

Mitigation

This year, Western Geophysical will reduce its airgun array from

the 1,500 in3 used in 1998 to 1,210 in3 and

investigate whether it is practical to modify the design to reduce

horizontal propagation of sound. These changes are expected to result

in lower received levels and therefore smaller safety ranges and

reduced takes by harassment than in 1998. However, because the 1,210

in3 array is a subset (with some minor variations) of the

1,500 in3 array (with 4 guns not firing), NMFS proposes to

prohibit Western Geophysical from firing more than the 8 airguns that

total 1,210 in3 during the 1999 open water seismic survey

without an amendment to the IHA (if issued).

Vessel-based observers will monitor marine mammal presence in the

vicinity of the seismic array throughout the seismic program. To avoid

the potential for serious injury to marine mammals, Western Geophysical

proposes to power down the seismic source if pinnipeds are sighted

within the area delineated by the 190 dB isopleth or 240 m (787.4 ft)

from the array operating at 5 m (16.4 ft) depth or 80 m (262.5 ft) from

the array operating at 2 m (6.6 ft) depth. Western

Geophysical will power down the seismic source if bowhead, gray, or

beluga whales are sighted within the area delineated by the 180 dB

isopleth or within 750 m (2,460.6 ft) of the array operating at 5 m (

16.4 ft) depth or 360 m (1,181.1 ft) of the array operating at 2 m (6.6

ft) depth. However, because these safety zones were based on the 1998

array configuration, within the first 10 days of Beaufort Sea

operations in 1999, Western Geophysical will measure and analyze the

sounds from Western's 1999 array operating at both 5 m (16.4 ft) and 2

m (6.6 ft) depths. This information will be provided to NMFS, along

with the contractor's recommendation as to whether any adjustments in

the safety radii are needed to meet the 190 and 180 dBrms

shutdown criteria.

In addition, Western Geophysical proposes to ramp-up the seismic

source to operating levels at a rate no greater than 6 dB/min anytime

the array has not been firing for 1-2 minutes (depending upon vessel

speed). Ramp-up will begin with an air volume discharge not exceeding

80 in3 with additional guns added at intervals appropriate

to limit the rate of increase to 6 dB/min.

Monitoring

As part of its application, Western Geophysical provided a

monitoring plan for assessing impacts to marine mammals from seismic

surveys in the Beaufort Sea. This monitoring plan is described in

Western Geophysical (1999) and in LGL Ltd. and Greeneridge Sciences

Inc. (1999b). 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, Western Geophysical plans to conduct the following:

Vessel-based Visual Monitoring

It is proposed that one or two biologist-observers aboard the

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 reticle binoculars during the

daytime supplemented with night-vision equipment during the night

(prior to mid-August, there are no hours of

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darkness). In addition, Western Geophysical proposes to experiment with

the illumination of the safety zone with high-intensity lighting this

year.

A total of four observers (three trained biologists and one Inupiat

observer/communicator) will be based aboard the seismic vessel. Use of

four observers is an increase over 1998 and will allow two observers to

be on duty simultaneously for up to 50 percent of the active airgun

hours. Use of two observers will increase the probability of detecting

marine mammals and two observers will be required to be on duty

whenever the seismic array is ramped up. Individual watches will

normally be limited to no more than 4 consecutive hours.

When mammals are detected within or about to enter the safety zone

designated to prevent injury to the animals (see Mitigation), the

geophysical crew leader will be notified so that shutdown procedures

can be implemented immediately.

Aerial Surveys

If the seismic program continues after August 31, Western

Geophysical proposes to conduct daily aerial surveys, weather

permitting, from September 4, 1999, until September 20, 1999, or until

1 day after the seismic program ends, if earlier than September 20.

This reduction in survey effort is considered appropriate because some

of the main questions about disturbance to bowheads from a nearshore

seismic operation have been answered previously.

The primary objective will be to document the occurrence,

distribution, and movements of bowhead and (secondarily) beluga and

gray whales in and near the area where they might be affected by the

seismic pulses. These observations will be used to estimate the level

of harassment takes and to assess the possibility that seismic

operations affect the accessibility of bowhead whales for subsistence

hunting. Pinnipeds will be recorded when seen. Aerial surveys will be

at an altitude of 300 m (1,000 ft) above sea level. Western Geophysical

proposes to fly at 457 m (1500 ft) altitude over areas where whaling is

occurring on that date and to avoid direct overflights of whaleboats

and Cross Island, where whalers from Nuiqsut are based during their

fall whale hunt.

The daily aerial surveys are proposed to cover a grid of 14 north-

south lines spaced 8 km (4.3 nm) apart and will extend seaward to about

the 100 m (328 ft) depth contour (typically about 65 km (35 nm)

offshore. This grid will extend from about 40 km (22 nm) east to 40 km

(22 nm) west of the area in which seismic operations are underway on

that date. This design will provide extended coverage to the west to

determine the westward extent of the offshore displacement of whales by

seismic. In 1999, no ``intensive'' grid surveys are planned, as

conducted in previous years.

Detailed information on the survey program can be found in Western

Geophysical (1999) and in LGL Ltd. and Greeneridge Sciences Inc.

(1999b), which are incorporated in this document by citation.

Acoustical Measurements

The acoustic measurement program proposed for 1999 is designed to

be continue work conducted in 1996 through 1998 (see LGL and

Greeneridge Sciences Inc., 1997, 1998, 1999a). The acoustic measurement

program is planned to include (1) vessel-based acoustic measurements,

(2) OBC-based acoustic measurements, (3) use of air-dropped sonobuoys

and (4) bottom-mounted acoustical recorders.

(1) A vessel-based acoustical measurement program is proposed for a

few days early in the seismic program. 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 of

airgun array to be used in 1999 as a function of distance and aspect

relative to the seismic source vessel and in relation to the operating

depth of the airguns, and (b) to measure the levels and frequency

composition of the vessel sounds emitted by vessels used regularly

during the 1999 program in those cases when these vessels have not

previously been measured adequately.

(2) Western Geophysical and its proposed consultant (Greeneridge

Sciences) will use recorded signals from Western's OBC system to help

document horizontal propagation of the seismic survey pulses.

(3) Sonobuoys will be dropped and monitored from bowhead survey

aircraft during September 4 through 20, 1999 (if the seismic operations

are continuing at that time). Sonobuoys will provide data on

characteristics of seismic pulses (and signal-to-ambient ratios) at

offshore locations, including some of those places where bowhead whales

are observed.

(4) Autonomous seafloor acoustic recorders will be placed on the

sea bottom at three locations to record low-frequency sounds nearly

continuously for up to 3 weeks at a time during September (if seismic

operations are continuing at that time). Information includes

characteristics of the seismic pulses, ambient noise, and bowhead

calls.

For a more detailed description of planned monitoring activities,

please refer to the application and supporting document (Western

Geophysical, 1999; LGL Ltd. and Greeneridge Sciences Inc., 1999b).

Estimates of Marine Mammal Take

Estimates of takes by harassment will be made through vessel and

aerial surveys. Preliminarily, Western Geophysical will estimate the

number of (a) marine mammals observed within the area ensonified

strongly by the seismic vessel; (b) marine mammals observed showing

apparent reactions to seismic pulses (e.g., heading away from the

seismic vessel in an atypical direction); (c) marine mammals subject to

take by type (a) or (b) here when no monitoring observations were

possible; and (d) bowheads displaced seaward from the main migration

corridor.

Reporting

Western Geophysical will provide an initial report on 1999

activities to NMFS within 90 days of the completion of the seismic

program. This report will provide dates and locations of seismic

operations, details of marine mammal sightings, estimates of the amount

and nature of all takes by harassment, and any apparent effects on

accessibility of marine mammals to subsistence users.

A final technical report will be provided by Western Geophysical

within 20 working days of receipt of the document from the contractor,

but no later than April 30, 2000. The final technical report will

contain a description of the methods, results, and interpretation of

all monitoring tasks.

Consultation

Under section 7 of the Endangered Species Act (ESA), NMFS completed

an informal consultation on the issuance of an IHA for similar

activities on July 23, 1998. 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, May 28, 1996) for open water seismic operations in the

Beaufort Sea, 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

[[Page 28997]]

document and, on July 18, 1996, NMFS concluded that neither

implementation of the proposed authorization for the harassment of

small numbers of several species of marine mammals incidental to

conducting seismic surveys during the open water season in the U.S.

Beaufort Sea nor the alternatives to that action would significantly

affect the quality of the human environment. As a result, the

preparation of an environmental impact statement on this action is not

required by section 102(2) of NEPA or its implementing regulations.

While this year's activity is a continuation of the seismic work

conducted between 1996 and 1998, NMFS determined that a new EA was

warranted based on the proposed construction of the Northstar project,

the collection of data from 1996 through 1998 on Beaufort Sea marine

mammals and the impacts of seismic activities on these mammals, and the

analysis of scientific data indicating that bowheads avoid nearshore

seismic operations by up to about 20 km (10.8 nm). Accordingly, a

review of the impacts expected from the issuance of an IHA has been

assessed in detail in the EA and in this document, and 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.

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.

While the number of potential incidental harassment takes will

depend on the distribution and abundance of marine mammals (which vary

annually due to variable ice conditions and other factors) in the area

of seismic operations, due to the distribution and abundance of marine

mammals during the projected period of activity and the location of the

proposed seismic activity in waters generally too shallow and distant

from the edge of the pack ice for most marine mammals of concern, the

number of potential harassment takings is estimated to be small. In

addition, no take by injury and/or death is anticipated, and the

potential for temporary or permanent hearing impairment will be avoided

through the incorporation of the mitigation measures mentioned in this

document. No rookeries, mating grounds, areas of concentrated feeding,

or other areas of special significance for marine mammals occur within

or near the planned area of operations during the season of operations.

Because bowhead whales are east of the seismic area in the Canadian

Beaufort Sea until late August/early September, seismic activities are

not expected to impact subsistence hunting of bowhead whales prior to

that date. After September 4, 1999, aerial survey flights for bowhead

whale assessments will be initiated. Appropriate mitigation measures to

avoid an unmitigable adverse impact on the availability of bowhead

whales for subsistence needs will be the subject of consultation

between Western Geophysical and subsistence users.

Also, while open-water seismic exploration in the U.S. Beaufort Sea

has some potential to influence seal hunting activities by residents of

Nuiqsut, because (1) the peak sealing season is during the winter

months, (2) the main summer sealing is off the Colville Delta, and (3)

the zone of influence by seismic sources on beluga and seals is fairly

small, NMFS believes that Western Geophysical's seismic survey will not

have an unmitigable adverse impact on the availability of these stocks

for subsistence uses.

Proposed Authorization

NMFS proposes to issue an IHA for the 1999 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,

beluga whales, ringed seals, bearded seals, and possibly spotted seals

and gray whales; 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 21, 1999.

Hilda Diaz-Soltero,

Director, Office of Protected Resources, National Marine Fisheries

Service.

[FR Doc. 99-13565 Filed 5-27-99; 8:45 am]

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