[Federal Register Volume 63, Number 97 (Wednesday, May 20, 1998)]
[Notices]
[Pages 27709-27714]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-13425]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[I.D. 051498A]
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 1998.
DATES: Comments and information must be received no later than June 19,
1998.
ADDRESSES: Comments on the application should be addressed to Michael
Payne, Chief, Marine Mammal Division, Office of Protected Resources,
NMFS, 1315 East-West Highway, Silver Spring, MD 20910-3225. A copy of
the application, a 1996 environmental assessment (EA), and a list of
references used in this document may be obtained by writing to this
address or by telephoning one of the contacts listed here.
FOR FURTHER INFORMATION CONTACT: Kenneth R. Hollingshead, (301) 713-
2055, Brad Smith, (907) 271-5006.
SUPPLEMENTARY INFORMATION:
Background
Section 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.)
directs the Secretary of Commerce to allow, upon request, the
incidental, but not intentional taking of marine mammals by U.S.
citizens who engage in a specified activity (other than commercial
fishing) within a specified geographical region if certain findings are
made and either regulations are issued or, if the taking is limited to
harassment, notice of a proposed authorization is provided to the
public for review.
Permission may be granted if NMFS finds that the taking will have a
negligible impact on the species or stock(s) and will not have an
unmitigable adverse impact on the availability of the species or
stock(s) for subsistence uses and that the permissible methods of
taking and requirements pertaining to the monitoring and reporting of
such taking are set forth.
On April 10, 1996 (61 FR 15884), NMFS published an interim rule
establishing, among other things, procedures for issuing incidental
harassment authorizations under section 101(a)(5)(D) of the MMPA for
activities in Arctic waters. For additional information on the
procedures to be followed for this authorization, please refer to that
document.
Summary of Request
On April 15, 1998, 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 Harrison Bay and Flaxman Island, AK. Weather
permitting, the survey is expected to take place between approximately
July 1 and October 20, 1998. A detailed description of the work
proposed for 1998 is contained in the application (Western Geophysical,
1998) and is available upon request (see ADDRESSES).
Description of Habitat and Marine Mammal Affected by the Activity
A detailed description of the Beaufort Sea ecosystem and its
associated marine mammals can be found in the EA prepared for this
authorization or in other documents (Minerals Management Service (MMS),
1992, 1996). This information is incorporated by reference and need not
be repeated here. A copy of the EA is available upon request (see
ADDRESSES).
Marine Mammals
The Beaufort/Chukchi Seas support a diverse assemblage of marine
mammals, including bowhead whales (Balaena mysticetus), gray whales
(Eschrichtius robustus), belukha (Delphinapterus leucas), ringed seals
(Phoca hispida), spotted seals (Phoca largha) and bearded seals
(Erignathus barbatus). Descriptions of the biology and distribution of
these species and of others can be found in several other documents
(Western Geophysical, 1998; BPXA, 1996b, 1998; Lentfer, 1988;
[[Page 27710]]
MMS, 1992, 1996; Small and DeMaster, 1995; Hill et al., 1997). Please
refer to those documents for information on these species.
Potential Effects of Seismic Surveys on Marine Mammals
Disturbance by seismic noise is the principal means of taking by
this activity. Support vessels and aircraft will provide a secondary
source of noise. The physical presence of vessels and aircraft could
also lead to non-acoustic effects involving visual or other cues.
Seismic surveys are used to obtain data about formations several
thousands of feet deep. The proposed seismic operation is an ocean
bottom cable (OBC) survey. OBC surveys involve dropping cables from a
ship to the ocean bottom, forming a patch consisting of 4 parallel
cables 10 kilometers (km) (6.2 mi) long, separated 750 m (2,500 ft)
from each other. Sensors (hydrophones) are attached to the cables.
These hydrophones are used to detect seismic energy reflected back from
underground rock strata. The original source of this energy is a
submerged acoustic source, called a seismic airgun array, that releases
compressed air into the water, creating an acoustical energy pulse that
is directed downward toward the seabed. The source level planned for
this project--a maximum of 249 dB re 1 Pa-m (zero to peak) or
53 bar-meters peak-to-peak from a 1,500 in3 array of
airguns--is in the lower to middle portion of the range of source
levels commonly used for seismic operations with airgun arrays
(Richardson et al., 1995). Normally, 36 seismic lines are run for each
patch, covering an area 6.0 km by 17.5 km (3.7 mi by 10.87 mi),
centered over the patch.
After sufficient data have been recorded to allow accurate mapping
of the rock strata, the cable is lifted onto the deck of a cable-
retrieval vessel, moved to a new location (ranging from several hundred
to a few thousand feet away), and placed onto the seabed again. For a
more detailed description of the seismic operation, please refer to the
application (Western Geophysical, 1998).
Depending upon ambient conditions and the sensitivity of the
receptor, underwater sounds produced by open water seismic operations
may be detectable a substantial distance away from the activity. Any
sound that is detectable is (at least in theory) capable of eliciting a
disturbance reaction by a marine mammal or of masking a signal of
comparable frequency (Western Geophysical, 1998). An incidental
harassment take is presumed to occur when marine mammals in the
vicinity of the seismic source, the seismic vessel, other vessels, or
aircraft react to the generated sounds or to visual cues.
Seismic pulses are known to cause bowhead whales to behaviorally
respond within a distance of several kilometers (Richardson et al.,
1995). Although some limited masking of low-frequency sounds (e.g.,
whale calls) is a possibility, the intermittent nature of seismic
source pulses (1 second in duration every 6 to 12 seconds) will limit
the extent of masking. Bowhead whales are known to continue calling in
the presence of seismic survey sounds, and their calls can be heard
between seismic pulses (Richardson et al., 1986). Masking effects are
expected to be absent in the case of belukhas, given that sounds
important to them are predominantly at much higher frequencies than are
airgun sounds (Western Geophysical, 1998).
Hearing damage is not expected to occur during the project. It is
not known whether a marine mammal very close to an airgun array would
be at risk of temporary or permanent hearing impairment, but temporary
threshold shift is a theoretical possibility for animals within a few
hundred meters (Richardson et al., 1995) of the source. However,
planned monitoring and mitigation measures (described later in this
document) are designed to detect marine mammals occurring near the
array and to avoid exposing them to sound pulses that have any
possibility of causing hearing damage.
When the received levels of noise exceed some behavioral reaction
threshold, cetaceans will show disturbance reactions. 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 (Western Geophysical, 1998).
Bowhead Whales
Various studies (Reeves et al., 1984, Fraker et al., 1985,
Richardson et al., 1986, Ljungblad et al., 1988) have reported that,
when an operating seismic vessel approaches within a few kilometers,
most bowhead whales exhibit strong avoidance behavior and changes in
surfacing, respiration, and dive cycles. Bowheads exposed to seismic
pulses from vessels more than 7.5 km (4.5 mi) away rarely showed
observable avoidance of the vessel, but their surface, respiration, and
dive cycles appeared altered in a manner similar to that observed in
whales exposed at a closer distance (BPXA, 1996a, 1996b, Western
Geophysical, 1998).
Within a 6-99 km (3.7-60 mi) range, it has not been possible to
determine a specific distance at which subtle behavioral changes no
longer occur (Richardson and Malme, 1993), given the high variability
observed in bowhead whale behavior (BPXA, 1996a, 1996b). Analysis of
the results from BPXA's 1996 seismic monitoring program does not
provide conclusive evidence about the radius of avoidance of bowheads
to the seismic program. The peak number of bowhead sightings was 10-20
km (6.2-12.3 mi) from shore during no-seismic periods and 20-30 km
(12.3-18.6 mi) from shore during periods that may have been influenced
by seismic noise. This difference was not statistically significant,
but the low numbers of sightings preclude meaningful interpretation
(Western Geophysical, 1998).
Inupiat whalers believe that migrating bowheads are sometimes
displaced at distances considerably greater than 6 to 8 km (3.7 to 5.0
mi)(Rexford, 1996). Scientific studies done to date have limitations as
discussed in part by Moore and Clark (1992) and MMS (1996). It is
possible that, when additional data are available, it will be
demonstrated that bowheads sometimes do avoid seismic vessels at
distances beyond 6 to 8 km (3.7 to 5.0 mi). Also, whalers have
mentioned that bowheads sometimes seem more ``skittish'' and more
difficult to approach when seismic exploration is underway in the area.
This ``skittish'' behavior may be related to the observed subtle
changes in the behavior of bowheads exposed to seismic pulses from
distant seismic vessels (Richardson et al., 1986).
Gray Whales
The reactions of gray whales to seismic pulses are similar to those
of bowheads. Migrating gray whales along the California coast were
noted to slow their speed of swimming, turn away from seismic noise
sources, and increase their respiration rates. Malme et al. (1983,
1984, 1988) concluded that approximately 50 percent showed avoidance
when the average received
[[Page 27711]]
pulse level was 170 dB (re 1 Pa @ 1 m). By some behavioral
measures, clear effects were evident at average pulse levels of 160+dB;
less consistent results were suspected at levels of 140-160 dB.
Belukha
The belukha is the only species of toothed whale (Odontoceti)
expected to be encountered in the Beaufort Sea. Because their hearing
threshold at frequencies below 100 Hz (where most of the energy from
airgun arrays is concentrated) is poor (125 dB re 1 Pa @ 1 m)
or more depending upon frequency (Johnson et al., 1989; Richardson et
al., 1991, 1995), belukha are not predicted to be strongly influenced
by seismic noise. However, because of the high source levels of seismic
pulses, airgun sounds may be audible to belukha at distances of 100 km
(Richardson and Wursig, 1997). The reaction distance for belukha,
although presently unknown, is expected to be less than that for
bowheads, given the presumed poorer sensitivity of belukhas than that
of bowheads for low-frequency sounds (Western Geophysical, 1998).
Ringed, Largha and Bearded Seals
No detailed studies of reactions by seals to noise from open water
seismic exploration have been published (Richardson et al., 1995).
However, there are some data on the reactions of seals to various types
of impulsive sounds (J. Parsons as quoted in Greene, et al. 1985;
Anon., 1975; Mate and Harvey, 1985). These studies indicate that ice
seals typically either tolerate or habituate to seismic noise produced
from open water sources.
Underwater audiograms have been obtained using behavioral methods
for three species of phocinid seals, ringed, harbor, and harp seals
(Pagophilus groenlandicus). These audiograms were reviewed in
Richardson et al. (1995). Below 30-50 kHz, the hearing threshold of
phocinids is essentially flat down to at least 1 kHz and ranges between
60 and 85 dB (re 1 Pa @ 1 m). There are few data on hearing
sensitivity of phocinid seals below 1 kHz. NMFS considers harbor seals
to have a hearing threshold of 70-85 dB at 1 kHz (60 FR 53753, October
17, 1995), and recent measurements for a harbor seal indicate that,
below 1 kHz, its thresholds deteriorate gradually to 97 dB (re 1
Pa @ 1 m) at 100 Hz (Kastak and Schusterman, 1995a, b).
Because no studies to date have focused on pinniped reaction to
underwater noise from pulsed, seismic arrays in open water (Richardson
et al., 1991, 1995), as opposed to in-air exposure to continuous noise,
substantive conclusions are not possible at this time. However,
assuming a sound pressure level of 80-100 dB over its threshold is
needed in order to cause annoyance and 130 dB for injury (pain), as is
the current thought based upon human studies (Advanced Research
Projects Agency and NMFS, 1995), it appears unlikely that pinnipeds
would be harassed or injured by low frequency sounds from a seismic
source unless they were within close proximity of the array. For
permanent injury, pinnipeds would likely need to remain in the high-
noise field for extended periods of time. Existing evidence also
suggests that, while they may be capable of hearing sounds from seismic
arrays, seals appear to tolerate intense pulsatile sounds without known
effect once they learn that there is no danger associated with the
noise (see, for example, NMFS/Washington Department of Wildlife, 1995).
In addition, they will apparently not abandon feeding or breeding areas
due to exposure to these noise sources (Richardson et al., 1991) and
may habituate to certain noises over time. Since seismic work is fairly
common in Beaufort Sea waters, pinnipeds have been previously exposed
to seismic noise and may not react to it after initial exposure.
Other Effects
For a discussion on the anticipated effects of ships, boats, and
aircraft, on marine mammals and their food sources, please refer to the
application (Western Geophysical, 1998). Information on these effects
is incorporated in this document by reference (see Western Geophysical,
1998).
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:
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Harassment takes in 1998
Species Population size -------------------------
Possible Probable
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Bowhead....................................... 8,000................................. 800 <400 gray="" whale....................................="" 23,000................................=""><10 0="" belukha.......................................="" 41,610................................="" 250=""><150 ringed="" seal...................................="" 1-1.5="" million.........................="" 400=""><300 spotted="" seal..................................="">200,000.............................. 10 <5 bearded="" seal..................................="">300,000.............................. 50 <30 ----------------------------------------------------------------------------------------------------------------="" 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="" (western="" geophysical,="" 1998).="" in="" particular,="" if="" migrating="" bowhead="" whales="" are="" displaced="" farther="" offshore="" by="" elevated="" noise="" levels,="" the="" harvest="" of="" these="" whales="" could="" be="" more="" difficult="" and="" dangerous="" for="" hunters.="" the="" harvest="" could="" also="" be="" affected="" if="" bowheads="" become="" more="" skittish="" when="" exposed="" to="" seismic="" noise="" (western="" geophysical,="" 1998).="" nuiqsut="" is="" the="" community="" closest="" to="" the="" area="" of="" the="" proposed="" activity,="" and="" it="" harvests="" bowhead="" whales="" only="" during="" the="" fall="" whaling="" season.="" in="" recent="" years,="" nuiqsut="" whalers="" typically="" take="" zero="" to="" four="" whales="" each="" season="" (western="" geophysical,="" 1998).="" nuiqsut="" whalers="" concentrate="" their="" efforts="" on="" areas="" north="" and="" east="" of="" cross="" island,="" generally="" in="" water="" depths="" greater="" than="" 20="" m="" (65="" ft).="" cross="" island,="" the="" principle="" field="" camp="" location="" for="" nuiqsut="" whalers,="" is="" located="" within="" the="" general="" area="" of="" the="" proposed="" seismic="" area.="" thus,="" the="" possibility="" and="" timing="" of="" potential="" seismic="" operations="" in="" the="" cross="" island="" area="" requires="" western="" geophysical="" to="" provide="" nmfs="" with="" a="" plan="" of="" cooperation="" (also="" called="" the="" communications="" and="" avoidance="" agreement)="" with="" north="" slope="" borough="" residents="" to="" avoid="" any="" unmitigable="" adverse="" impact="" on="" subsistence="" needs.="" whalers="" from="" the="" village="" of="" kaktovik="" search="" for="" whales="" east,="" north,="" and="" west="" [[page="" 27712]]="" of="" the="" village.="" kaktovik="" is="" located="" 50="" mi="" (80="" km)="" east="" of="" the="" easternmost="" end="" of="" western="" geophysical's="" planned="" 1998="" seismic="" exploration="" area.="" the="" westernmost="" reported="" harvest="" location="" was="" about="" 21="" km="" (13="" mi)="" west="" of="" kaktovik,="" near="" 70="" deg.10'n,="" 144="" deg.w="" (kaleak,="" 1996).="" that="" site="" is="" approximately="" 60="" km="" (37="" mi)="" east="" of="" the="" closest="" part="" of="" western="" geophysical's="" planned="" seismic="" exploration="" area="" for="" 1998="" (western="" geophysical,="" 1998).="" whalers="" from="" the="" village="" of="" barrow="" search="" for="" bowhead="" whales="" much="" further="" from="" the="" planned="" seismic="" area,="">200 km (>125 mi) west (Western
Geophysical, 1998).
The location of the proposed seismic activity is south of the
center of the westward migration route of bowhead whales, but there is
some overlap. Western Geophysical (1998) believes that, although whales
may be able to hear the sounds emitted by the seismic array out to a
distance of 50 km (30 mi) or more, it is unlikely that changes in
migration route will occur at distances of >25 km (>15 mi).
Alternatively, Inupiat whalers believe that bowheads begin to divert
from their normal migration path more than 48 km (35 mi) away (MMS,
1996).
It is recognized that it is difficult to determine the maximum
distance at which reactions occur (Moore and Clark, 1992). As a result,
Western Geophysical will participate in a Communications and Avoidance
Agreement with the whalers to reduce any potential interference with
the hunt. Also, it is believed that the monitoring plan proposed by
Western Geophysical (1998; also see LGL Ltd. and Greeneridge Sciences
Inc, 1998) will provide information that will help resolve
uncertainties about the effects of seismic exploration on the
accessibility of bowheads to hunters.
While seismic exploration has some potential to influence
subsistence seal hunting activities, the peak season for seal hunting
is during the winter months when the harvest consists almost
exclusively of ringed seals (Western Geophysical, 1998). In summer,
boat crews hunt ringed, spotted and bearded seals (Western Geophysical,
1998). The most important sealing area for Nuiqsut hunters is off the
Colville delta, extending as far west as Fish Creek and as far east as
Pingok Island (Western Geophysical, 1998). This area overlaps with the
westernmost portion of the planned seismic area. In this area, during
summer, sealing occurs by boat when hunters apparently concentrate on
bearded seals (Western Geophysical, 1998).
Mitigation
Western Geophysical plans to use biological observers to monitor
marine mammal presence in the vicinity of the seismic array. To avoid
the potential for serious injury to marine mammals, Western Geophysical
will power down the seismic source if pinnipeds are sighted within the
area delineated by the 190 dB isopleth or:
(1) within 60 m (197 ft) of a single airgun or an array of
60 in3.
(2) within 170 m (558 ft) of an array >60 in\3\ and 750
in\3\ at <2.5 m="" (8.3="" ft)="" depth;="" (3)="" within="" 280="" m="" (919="" ft)="" of="" an="" array="">60 in\3\ and 750
in\3\ operating at >2.5 m (8.3 ft) depth;
(4) within 200 m (656 ft) of an array >750 in\3\ and
1500 in\3\ operating at <2.5 m="" (8.3="" ft)="" depth;="" (5)="" within="" 350="" m="" (1,148="" ft)="" of="" an="" array="">750 in\3\ and
1500 in\3\ operating at >2.5 m (8.3 ft) depth;
Western Geophysical will power down the seismic source if bowhead,
gray, or belukha whales are sighted within the area delineated by the
180 dB isopleth or:
(1) within 160 m (525 ft) of a single airgun or an array of >60
in\3\;
(2) within 660 m (2,165 ft) of an array >60 in\3\ and
750 in\3\ at <2.5 m="" (8.3="" ft)="" depth;="" (3)="" within="" 900="" m="" (2,953="" ft)="" of="" an="" array="">60 in\3\ and
750 in\3\ operating at >2.5 m (8.3 ft) depth;
(4) within 700 m (2,297 ft) of an array >750 in\3\ and
840 in\3\ operating at <2.5 m="" (8.3="" ft)="" depth;="" and="" (5)="" within="" 900="" m="" (2,953="" ft)="" of="" an="" array="">750 in\3\ and
840 in\3\ operating at >2.5 m (8.3 ft) depth;
In addition, Western Geophysical proposes to ramp-up the seismic
source to operating levels at a rate no greater than 6 dB/min. If the
array includes airguns of different sizes, the smallest gun will be
fired first. Additional guns will be added at intervals appropriate to
limit the rate of increase in source level to a maximum of 6 dB/min.
Monitoring
As part of its application, 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 (1998) and in LGL Ltd. and Greeneridge Sciences
Inc. (1998). Although Western Geophysical is prepared to discuss
coordination of research to the extent practicable with other seismic
operations, Western Geophysical is prepared to sponsor an independent
program. 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
A minimum of 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 reticulated binoculars during the daytime and with night-
vision equipment during the night (prior to mid-August, there are no
hours of darkness). Individual watches will normally be limited to no
more than 4 consecutive hours.
When mammals are detected within a safety zone designated to
prevent injury to the animals (see Mitigation), the geophysical crew
leader will be notified so that shutdown procedures can be implemented
immediately.
Aerial Surveys
From September 1, 1998, until 3 days after the seismic program
ends, aerial surveys will be conducted daily, weather permitting. The
primary objective will be to document the occurrence, distribution, and
movements of bowhead and belukha whales in and near the area where they
might be affected by the seismic pulses. These observations will be
used to estimate the level of harassment takes and to assess the
possibility that seismic operations affect the accessibility of bowhead
whales for subsistence hunting. Pinnipeds will be recorded when seen.
Aerial surveys will be at an altitude of 300 m (1,000 ft) above sea
level. Western Geophysical proposes to avoid overflights of the Cross
Island area where whalers from Nuiqsut are based during their fall
whale hunt.
Consistent with 1996 and 1997 aerial surveys in the U.S. Beaufort
Sea, the daily aerial surveys are proposed to cover two grids: (1) A
grid of 12 north-south lines spaced 8 km (5 mi) apart and extending
from about 20 km (12.5 mi) west of the western side of the then-current
seismic exploration area to 50 km (30 mi) east of its eastern edge, and
from the barrier islands north to approximately the 100 m (328 ft)
depth contour; and (2) a grid of 4 survey lines within the above
region, also spaced 8 km (5 mi) apart and mid-way between the longer
lines, to provide more intensive coverage of the area of the seismic
operations and immediate surrounding waters.
[[Page 27713]]
When the seismic program is relocated east or west along the coast
during the 1998 season, both survey grids will be relocated a
corresponding distance along the coast. Information on the survey
program can be found in Western Geophysical (1998) and in LGL Ltd. and
Greeneridge Sciences Inc. (1998), which are incorporated in this
document by reference.
Acoustical Measurements
The acoustic measurement program proposed for 1998 is designed to
be continue work conducted in 1996 and 1997 (see BPXA, 1996a, 1997, and
1998; LGL Ltd. and Greeneridge Sciences Inc., 1996, 1997, and 1998).
The acoustic measurement program is planned to include (1) boat-based
acoustic measurements, (2) OBC-based acoustic measurements, (3) use of
air-dropped sonobuoys and (4) bottom-mounted acoustical recorders.
The boat-based acoustical measurement program is proposed for a 7-
day period in August 1998. The objectives of this survey will be as
follows: (1) To measure the levels and other characteristics of the
horizontally propagating seismic survey sounds from the type(s) of
airgun array(s) to be used in 1998 as a function of distance and aspect
relative to the seismic source vessel(s) and to water depth.
(2) To measure the levels and frequency composition of the vessel
sounds emitted by vessels used regularly during the 1998 program.
(3) To obtain additional site-specific ambient noise data, which
determine signal-to-noise ratios for seismic and other acoustic signals
at various ranges from their sources.
Western Geophysical and its proposed consultant (Greeneridge
Sciences) are investigating the use of the OBC-system to help document
horizontal propagation of the seismic surveys. In addition, during late
August and September, autonomous seafloor acoustic recorders will be
placed on the sea bottom at 3 locations to record low-frequency sounds
nearly continuously for up to 3 weeks at a time. Information includes
characteristics of the seismic pulses, ambient noise, and bowhead
calls. Additional data on these noise sources will be obtained from
sonobuoys dropped from aircraft after September 1.
For a more detailed description of planned monitoring activities,
please refer to the application and supporting document (Western
Geophysical, 1998; LGL Ltd. and Greeneridge Sciences Inc., 1998).
Estimates of Marine Mammal Take
Estimates of takes by harassment will be made through vessel and
aerial surveys. Preliminarily, Western Geophysical will estimate the
number of (1) 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) 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 1998
activities to NMFS within 90 days of the completion of the seismic
program. This report will provide dates and locations of seismic
operations, details of marine mammal sightings, estimates of the amount
and nature of all takes by harassment, and any apparent effects on
accessibility of marine mammals to subsistence users.
A final technical report will be provided by Western Geophysical
within 20 working days of receipt of the document from the contractor,
but no later than April 30, 1999. The final technical report will
contain a description of the methods, results, and interpretation of
all monitoring tasks.
Consultation
Under section 7 of the Endangered Species Act (ESA), NMFS completed
an informal consultation on the issuance of an incidental harassment
authorization for similar activities on June 26, 1997. A copy of that
document is available upon request (see ADDRESSES). If an authorization
to incidentally harass listed marine mammals is issued under the MMPA,
NMFS will issue an Incidental Take Statement under section 7 of the
ESA.
National Environmental Policy Act (NEPA)
In conjunction with the 1996 notice of proposed authorization (61
FR 26501, 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
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. A
copy of the EA is available upon request (see ADDRESSES).
This year's activity is a continuation of the seismic work
conducted in 1996 and 1997. For Western Geophysical's 1998 application,
NMFS has conducted a review of the impacts expected from the issuance
of an Incidental Harassment Authorization in comparison to those
impacts evaluated in 1996. As assessed in detail in this document, NMFS
has preliminarily determined that there will be no more than a
negligible impact on marine mammals from the issuance of the harassment
authorization and that there will not be any unmitigable impacts to
subsistence communities, provided the mitigation measures required
under the authorization are implemented. Because the activity is
substantially the same as the one conducted in 1996 and no new impacts
on the environment have been identified, a new EA is not warranted and,
therefore, the preparation of an Environmental Impact Statement on this
action is not required by section 102(2) of NEPA or its implementing
regulations.
Conclusions
NMFS has preliminarily determined that the short-term impact of
conducting seismic surveys in the U.S. Beaufort Sea will result, at
worst, in a temporary modification in behavior by certain species of
cetaceans and possibly pinnipeds. While behavioral modifications may be
made by these species to avoid the resultant noise, this behavioral
change is expected to have a negligible impact on the animals.
As the number of potential incidental harassment takes will depend
on the distribution and abundance of marine mammals (which vary
annually due to variable ice conditions and other factors) in the area
of seismic operations, due to the distribution and abundance of marine
mammals during the projected period of activity and the location of the
proposed seismic activity in waters generally too shallow and distant
from the edge of the pack ice for most marine mammals of concern, the
number of potential harassment takings is estimated to be small. In
addition, no take by injury and/or death is anticipated, and the
potential for temporary or permanent hearing impairment will be avoided
through the incorporation of the mitigation
[[Page 27714]]
measures mentioned in this document. No rookeries, mating grounds,
areas of concentrated feeding, or other areas of special significance
for marine mammals occur within or near the planned area of operations
during the season of operations.
Because bowhead whales are east of the seismic area in the Canadian
Beaufort Sea until late August/early September, seismic activities are
not expected to impact subsistence hunting of bowhead whales prior to
that date. After August 31, 1998, 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 belukha 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 incidental harassment authorization for
the 1998 Beaufort Sea open water season for a seismic survey provided
the above mentioned mitigation, monitoring, and reporting requirements
are incorporated. NMFS has preliminarily determined that the proposed
seismic activity would result in the harassment of only small numbers
of bowhead whales, gray whales, and possibly belukha whales, bearded
seals, and largha seals; would have a negligible impact on these marine
mammal stocks; and would not have an unmitigable adverse impact on the
availability of marine mammal stocks for subsistence uses.
Information Solicited
NMFS requests interested persons to submit comments, and
information, concerning this request (see ADDRESSES).
Dated: May 14, 1998.
Patricia A. Montanio,
Deputy Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 98-13425 Filed 5-19-98; 8:45 am]
BILLING CODE 3510-22-F
