[Federal Register Volume 64, Number 103 (Friday, May 28, 1999)]
[Notices]
[Pages 28992-28997]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-13565]
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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
[[Page 28993]]
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
------------------------------------------------------------------------
Bowhead........................... 9,900
160 dB criterion.................. 1,000 <500
20 km criterion................... 2,500 1,250
Gray whale........................ 26,600 <10 0
Beluga............................ 39,258 250 <150
Ringed seal*...................... 1-1.5 million 400 <200
Spotted seal*..................... >200,000 10 <2
Bearded seal*..................... >300,000 50 <15
------------------------------------------------------------------------
* Some individual seals may be harassed more than once.
Effects of Seismic Noise and Other Activities on Subsistence Needs
The disturbance and potential displacement of marine mammals by
sounds from seismic activities are the principle concerns related to
subsistence use of the area. The harvest of marine mammals (mainly
bowhead whales, ringed seals, and bearded seals) is central to the
culture and subsistence economies of the coastal North Slope
communities. In particular, if migrating bowhead whales are displaced
farther offshore by elevated noise levels, the harvest of these whales
could be more difficult and dangerous for hunters. The harvest could
also be affected if bowheads become more skittish when exposed to
seismic noise.
Nuiqsut is the community closest to the area of the proposed
activity, and it harvests bowhead whales only during the fall whaling
season. In recent years,
[[Page 28995]]
Nuiqsut whalers typically take two to four whales each season (Western
Geophysical, 1999). 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 Western Geophysical to
provide NMFS with either a Plan of Cooperation with North Slope Borough
residents or to identify measures that have been or will be taken to
avoid any unmitigable adverse impact on subsistence needs. Western
Geophysical's application has identified those measures that will be
taken to minimize any adverse effect on subsistence. In addition, the
timing of seismic operations in and east of the Cross Island area will
be addressed in a Conflict and Avoidance Agreement (C&AA) with the
Nuiqsut whalers and the AEWC (Western Geophysical, 1999).
Whalers from the village of Kaktovik search for whales east, north,
and west of the village. Kaktovik is located 60 km (32.4 nm) east of
the easternmost end of Western Geophysical's planned 1999 seismic
exploration area. The westernmost reported harvest location was about
21 km (11.3 nm) west of Kaktovik, near 70o10'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
[[Page 28996]]
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
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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]
BILLING CODE 3510-22-F