[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:

------------------------------------------------------------------------
                                                             Number of  
                                            Density\3\      animals\4\  
              Whale species               (number/km\2\)     acoustic   
                                                            harassment  
------------------------------------------------------------------------
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
                                                         ---------------
    Total...............................  ..............             81 
------------------------------------------------------------------------
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    
------------------------------------------------------------------------
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]
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