[Federal Register Volume 60, Number 109 (Wednesday, June 7, 1995)]
[Notices]
[Pages 30066-30068]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-13966]
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DEPARTMENT OF COMMERCE
[I.D. 053095D]
Small Takes of Marine Mammals Incidental to Specified Activities;
Offshore Seismic Activities in Southern California
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice of receipt of application and proposed authorization for
a small take exemption; request for comments.
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SUMMARY: NMFS has received a request from the Exxon Company, U.S.A.,
Thousand Oaks, CA, for authorization to take small numbers of cetaceans
by harassment incidental to conducting a three-dimensional (3-D)
seismic survey in the Santa Ynez Unit (SYU), located in the western
portion of the Santa Barbara Channel, offshore California, in Federal
waters. Under the Marine Mammal Protection Act (MMPA), NMFS is
requesting comments on its proposal to authorize Exxon to incidentally
take, by harassment, small numbers of cetaceans in the above mentioned
area for a period of 1 year.
DATES: Comments and information must be received no later than July 7,
1995.
ADDRESSES: Comments on the application should be addressed to Chief,
Marine Mammal Division, Office of Protected Resources, National Marine
Fisheries Service, 1315 East-West Highway, Silver Spring, MD 20910-
3225. A copy of the application 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 below.
FOR FURTHER INFORMATION CONTACT: Kenneth Hollingshead, Office of
Protected Resources at 301-713-2055, or Craig Wingert, Southwest
Regional Office at 310-980-4021.
SUPPLEMENTARY INFORMATION:
Background
Section 101(a)(5)(A) 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 regulations are
issued.
Permission may be granted if NMFS finds that the taking will have a
negligible impact on the species or stock(s); will not have an
unmitigable adverse impact on the availability of the species or
stock(s) for subsistence uses; and the permissible methods of taking
and requirements pertaining to the monitoring and reporting of such
taking are set forth.
On April 30, 1994, the President signed Public Law 103-238, The
Marine Mammal Protection Act Amendments of 1994. One part of this law
added a new subsection 101(a)(5)(D) to the MMPA to establish an
expedited process by which citizens of the United States can apply for
an authorization to incidentally take small numbers of marine mammals
by harassment. The MMPA defines ``harassment'' as:
* * * any act of pursuit, torment, or annoyance which (a) has
the potential to injure a marine mammal or marine mammal stock in
the wild; or (b) has the potential to disturb a marine mammal or
marine mammal stock in the wild by causing disruption of behavioral
patterns, including, but not limited to, migration, breathing,
nursing, breeding, feeding, or sheltering.
New subsection 101(a)(5)(D) establishes a 45-day time limit for
NMFS review of an application followed by a 30-day public notice and
comment period on any proposed authorizations for the incidental
harassment of small numbers of marine mammals. Within 45 days of the
close of the comment period, NMFS must either issue or deny issuance of
the authorization.
Summary of Request
On May 11, 1995, NMFS received an application from Exxon requesting
an authorization for the harassment of small numbers of cetaceans
incidental to conducting a 3-D seismic survey within the SYU, located
in the western portion of the Santa Barbara Channel, off Southern
California, in U.S. waters. As described in their application (Exxon,
1995) Exxon's survey will cover an area of approximately 303 km\2\ of
the outer continental shelf and will require approximately 2 months,
commencing in August 1995, to complete. The survey will provide
subsurface data that will enable Exxon to more accurately assess the
oil and gas reservoirs in order to optimally locate future development
wells from existing platforms.
Deep seismic surveys obtain data about formations several thousands
of meters deep, such as the hydrocarbon-bearing Monterery Formation in
the SYU. These surveys are accomplished by transmitting sound waves
into the earth, which are reflected off subsurface formations and
recorded with detectors in the water column. A typical marine seismic
source is an airgun array that releases compressed air into the water,
creating an acoustical energy pulse that is directed into the earth.
Hydrophones spaced along a streamer cable just below the surface of the
water receive the reflected energy from the subsurface formations and
transmit data to the seismic vessel. On board the vessel, the signals
are amplified, digitized, and recorded on magnetic tape.
The contract survey vessel will transverse the SYU area along east-
west lines, approximately 24.9 km in length parallel to the coastline,
with a few south-north lines approximately 9.65 km in length to be
acquired over key geological features. There will be approximately 64
east-west transects and 6 south-north transects over the 2-month
period. Field operations will be conducted 24 hours a day, although
about half of that time will be consumed by turning the vessel and
maneuvering. The airgun arrays will be shut down during turning and
maneuvering and will be powered up slowly over a 5-minute period when
turned back on. Eighty to 90 percent of the proposed survey will be
accomplished with a single vessel. A second vessel will be used to
undershoot platform structures and some complex subsurface geological
features of limited areal extent. Two vessels abreast each other will
be used for undershooting. The survey is designed to acquire the
maximum amount of data in the minimum amount of time. Exxon plans to
initiate the survey around August 1, 1995, and complete data collection
approximately October 1, 1995, prior to the onset of adverse weather
and gray whale migration in the Santa Barbara Channel area.
Exxon will employ a 90-m seismic vessel to acquire the survey data.
The seismic source will consist of dual airgun arrays deployed 37.5 m
apart and fired alternately to acquire separate records. Each array
will consist of 18 airguns of differing strengths producing a total of
8.62 megapascals peak to peak energy. The airguns will be sleeve type
guns towed at a depth of 5 to 10 m below the water surface. Paravanes
will be deployed to separate the airgun arrays.
The proposed survey could potentially affect marine mammals due to
disturbance by sound (i.e., acoustic harassment).
Description of Habitat and Marine Mammal Affected by the Activity
The Southern California Bight (SCB) including the Channel Islands,
supports a diverse assemblage of marine mammals including cetaceans
(whales, dolphins, and porpoises) and pinnipeds (seals and sea lions).
A detailed description of the SCB and its associated marine mammals can
be found in the Federal Register (56 FR 1606, January 16, 1991) and
need not be repeated here.
Approximately 34 species of marine mammals inhabit the SCB. They
include 6 species of pinnipeds and 27 species of cetaceans. The status
of these species has been reviewed previously (NMFS, 19911).
Recently, NMFS released draft revised stock assessment reports (59 FR
40527; August 9, 1994).2 These reports include information on
status and trends of marine mammals and an assessment of all human-
caused mortality and serious injury of the various stocks of marine
mammals. [[Page 30067]]
\1\A list of references used in this document can be obtained by
writing to the address provided above (see ADDRESSES).
\2\NMFS has established a bulletin board for electronic
retrieval of marine mammal stock assessment reports. The reports are
stored as Wordperfect 5.1 files and may be downloaded by a modem
link to the following telephone number: (703) 218-2595. Within your
communications software, specify 8 data bits, no parity, and 1 stop
bit. Set up as an ANSI terminal and use your appropriate baud rate
up to 19,200. Instructions to download files are available on
screen.
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It is possible that acoustic harassment by seismic survey
operations could potentially occur for mysticete whales and possibly
the sperm whale, since they represent the only species assumed to hear
well the noise associated with airguns. Given the survey location and
the time period within which the survey will be conducted, the species
of whales that could be potentially affected are the following: (1)
Blue whale (Balaenoptera musculus); (2) fin whale (Balaenoptera
physalus); (3) humpback whale (Megaptera novaeangliae); (4) minke whale
(Balaenoptera acutorostrata); (5) sperm whale (Physeter macrocephalus;
(6) pygmy sperm whale (Kogia breviceps); (7) sei whale (Balaenoptera
borealis); and (8) Bryde's whale (Balaenoptera edeni). In addition,
because this proposed authorization may extend into the period of time
when gray whales (Eschrichtius robustus) may be present, that species
may also be affected. Detailed descriptions of the distribution and
abundance of these species in California waters can be found in Barlow
(1994, 1995), Forney (1994) Forney et al. (1995) and NMFS (1993).
Potential Effects of Seismic Surveys on Marine Mammals
The airguns emit pulsed energy primarily at frequencies in the 10
to 300 Hz range. Dolphin, porpoise, seal, and sea lion hearing is
believed to be poor at frequencies less than 1,000 Hz, and thus it is
unlikely that the airgun noise would significantly affect them.
Acoustic harassment takes, therefore, need to be assessed only for
mysticete whales and the sperm whale, because they represent the only
group that is believed to be able to hear or possibly react to the
sound associated with seismic activities.
To determine the numbers of whales that could potentially be
subject to acoustic harassment, marine mammal densities were applied
over the anticipated zone of potential disturbance (ZPD). The densities
utilized (Barlow, 1995) were obtained along the California coast during
the summer and fall seasons of the year, which is consistent with the
time period of the proposed survey.
The ZPD was conservatively assumed to be the entire survey area
(303 km2) plus an additional area to account for the travel of
sound outside the survey area perimeter. To determine the outer
boundary of the affected area, it was concluded that the 160 dB level
could be considered a conservative end point for potential marine
mammal acoustic harassment. Tyack (1988) indicates that avoidance
behavior occurs only at relatively close ranges at decibels greater
than 160-170 dB for pulsed sounds such as those from airguns. It has
been presumed that less than 10 percent of animals located beyond the
160 dB range would be subjected to acoustic harassment (Malme et al.,
1984; LGL Assoc., 1991). Therefore, NMFS has adopted a level of 160 dB
(re 1Pa) as an acceptable level for impulsive noise based upon
the best scientific evidence available.
For the proposed survey, the 160 dB isopleth occurs at a radius of
approximately 5.2 km from the seismic source (Exxon, 1995). The ZPD was
calculated by expanding the entire perimeter of the SYU survey area by
5.2 km. This area was calculated to be 470 km\2\, and when added to the
survey area 303 km\2\, resulted in a total ZPD of 773 km\2\. However,
at any instant of time, harassment would be limited to an area
approximately 84.9 km\2\, with a radius of 5.2 km around the airgun
array when the array is generating sound.
Using the above information and assumptions, the number of marine
mammals that could potentially be subject to acoustic harassment is as
follows:
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Number of
Density\3\ animals\4\
Whale species (number/km\2\) acoustic
harassment
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Blue whale.............................. 0.033 26
Fin whale............................... 0.013 10
Humpback whale.......................... 0.009 7
Minke whale............................. 0.008 6
Sperm whale............................. 0.011 9
Pygmy sperm whale....................... 0.013 10
Sei whale............................... 0.001 1
Bryde's whale........................... 0.001 1
Gray whale.............................. 0.014 11
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Total............................... .............. 81
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3From Barlow (1995).
4Density X ZPD=No. Animals.
[[Page 30068]] However, because the potential exists that the
survey schedule could be delayed and overlap with the southbound gray
whale migration, some or all of the survey could also potentially
result in harassing gray whales. To cover that possibility, a proposed
authorization for harassment takes of gray whales has been included.
Applying Forney et al.'s (1995) gray whale density from the winter/
spring surveys (0.014) to the ZPD (773 km\2\ indicates that 11 gray
whales could potentially be subject to acoustic harassment.
Also, while the assumption can be made that a population of 70-81
cetaceans may be harassed during the SYU survey, because the 160 dB ZPH
at any one instant of time is only a portion of the entire 773 km\2\
ZPD, and because the seismic array is turned off while repositioning on
the succeeding transect, these cetaceans, at least theoretically, may
be harassed more than once during the course of the survey, unless they
leave the area as a result of either normal transitting (migration) or
seismic noise.
NMFS estimates that each east-west and south-north transect would
have a ZPH approximately 344 km\2\ and 147.3 km\2\, respectively and
each of the 64 east-west or 6 south-north transects comprise
approximately 45 percent or 19 percent respectively, of the total ZPD.
As a result, theoretically there is the potential for the SYU seismic
survey to result in 2,360 harassment takings proportionally divided as
follows:
------------------------------------------------------------------------
Total number
Whale species Density (No./ Total ZPD of harassment
km\2\ (km2) takes
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Blue whale.............. 0.033 22,900 756
Fin whale............... 0.013 22,900 298
Humpback whale.......... 0.009 22,900 206
Minke whale............. 0.008 22,900 183
Sperm whale............. 0.011 22,900 252
Pygmy sperm whale....... 0.013 22,900 298
Sei whale............... 0.001 22,900 23
Bryde's whale........... 0.001 22,900 23
Gray whale.............. 0.014 22,900 \5\321
------------------------------------------------------------------------
\5\As gray whales generally migrate from feeding grounds to breeding
lagoons offshore Baja California from November-December, if the
seismic survey is delayed from its anticipated commencement date, some
harassment of this species may occur.
Mitigation
To avoid potential injury to marine mammals, NMFS proposes to: (1)
Require airguns to be ramped-up to operating levels over a 5-minute
period at the commencement of operations, when beginning a new
trackline or anytime that the array is powered down; (2) recommend not
turning the array off at times when restarting the array would occur
during nighttime hours; and (3) if marine mammals are observed within
the 195 dB isopleth (91.5 m (300 ft) of the source), starting
operations must be delayed until all marine mammals are outside the 195
dB zone. It is proposed that NMFS-approved observers be required to
make these observations.
Monitoring
NMFS proposes that the holder of the Incidental Harassment
Authorization will monitor the impact of seismic activities on the
marine mammal populations within the SYU. Monitoring will be conducted
during daylight hours by NMFS-approved observers. In addition,
monitoring will begin 30 minutes prior to any time the seismic array is
turned on and will continue until turned off. Monitoring will consist
of noting the numbers and species of all marine mammals seen within the
ZPH, and any behavioral responses or modifications due either to the
seismic array or by the vessel. A report on this monitoring program
will be required to be submitted to NMFS within 90 days of completion
of the survey. Specific monitoring and reporting requirements will be
specified in the Incidental Harassment Authorizaion, if issued.
Consultation
Under section 7 of the Endangered Species Act, NMFS has begun
consultation on the proposed issuance of this authorization.
Consultation will be concluded upon completion of the comment period
and consideration of those comments in the final determination on
issuance of an authorization.
Conclusions
NMFS has determined preliminarily that the short-term impact from
conducting a 3-D seismic survey within the SYU may result in a
temporary modification in behavior by certain species of cetaceans.
While behavioral modifications may be made by these species of
cetaceans to avoid seismic noise, this behavioral change is expected to
have only a negligible impact on the animals.
There is no known recent subsistence use of marine mammals in
southern California.
Proposed Authorization
NMFS proposes to issue an incidental harassment authorization for 1
year for a 3-D seismic survey within the SYU provided the above
mentioned 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 mysticete cetaceans,
sperm whales, and possibly pygmy sperm whales; will have a negligible
impact on these cetacean stocks; and will not have an unmitigable
adverse impact on the availability of this stock for subsistence uses.
Information Solicited
NMFS requests interested persons to submit comments, information,
and suggestions concerning this request (see ADDRESSES).
Dated: June 2, 1995.
William W. Fox, Jr.,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 95-13966 Filed 6-6-95; 8:45 am]
BILLING CODE 3510-22-W
