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[Federal Register Volume 65, Number 125 (Wednesday, June 28, 2000)]
[Notices]
[Pages 39871-39878]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-16228]

[[Page 39871]]

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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[I.D.022800B]

Small Takes of Marine Mammals Incidental to Specified Activities; 
Marine Seismic-Reflection Data Collection in Southern California

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice of issuance of an incidental harassment authorization.

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SUMMARY: In accordance with provisions of the Marine Mammal Protection 
Act (MMPA) as amended, notification is hereby given that an Incidental 
Harassment Authorization (IHA) to take small numbers of marine mammals 
by harassment incidental to collecting marine seismic-reflection data 
in southern California waters has been issued to the U.S. Geological 
Survey (USGS).

DATES: This authorization is effective from June 5, 2000, through 
September 30, 2000.

ADDRESSES: A copy of the application may be obtained by writing to 
Donna Wieting, Chief, Marine Mammal Conservation Division, Office of 
Protected Resources, NMFS, 1315 East-West Highway, Silver Spring, MD 
20910-3225, or by telephoning one of the contacts listed here.

FOR FURTHER INFORMATION CONTACT: Kenneth R. Hollingshead, NMFS, (301) 
713-2055, or Christina Fahy, NMFS, 562-960-4023.

SUPPLEMENTARY INFORMATION:

Background

    Sections 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 small numbers 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, a 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), will not have an 
unmitigable adverse impact on the availability of the species or 
stock(s) for subsistence uses, and if permissible methods of taking and 
requirements pertaining to the monitoring and reporting of such takings 
are set forth. NMFS has defined ``negligible impact'' in 50 CFR 216.103 
as ``...an impact resulting from the specified activity that cannot be 
reasonably expected to, and is not reasonably likely to, adversely 
affect the species or stock through effects on annual rates of 
recruitment or survival.''
    Subsection 101(a)(5)(D) of the MMPA established 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 now 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.

    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 January 24, 2000, NMFS received a request from the USGS for 
authorization to take small numbers of several species of marine 
mammals by harassment incidental to collecting marine seismic-
reflection data from waters off southern California. Seismic data will 
be collected during a 3-week period between May and July 2000, 
preferably June, to determine the source of the invasion of seawater 
into freshwater aquifers that are critical to the Los Angeles-San Pedro 
area water supply and to support studies of the regional landslide and 
earthquake hazards for people within the coastal cities between Santa 
Barbara and San Diego.

Background

    The USGS proposes to conduct a high-resolution seismic survey 
offshore from Southern California. For a 3-week period between May and 
July 2000, preferably in June, the USGS would like to collect seismic-
reflection data to investigate: (1) the intrusion of seawater into 
freshwater coastal aquifers that are critical to the water supply for 
people within the Los Angeles- San Pedro area and (2) the hazards posed 
by landslides, tsunamis, and potential earthquake faults in the 
nearshore region from Santa Barbara to San Diego. Both of these tasks 
are multi-year efforts that require high-resolution, seismic-reflection 
data using a minisparker acoustic source.
    Coastal Southern California is the most highly populated urban area 
along the U.S. Pacific coast with 30 percent of the California 
population (approximately 10 million people) living in Los Angeles 
County alone. The primary objectives of the USGS research are to 
provide information (1) to understand and help mitigate the intrusion 
of salt water into coastal aquifer systems resulting from ground-water 
overdraft, and (2) to help mitigate the earthquake threat to this area. 
Data collected to address the salt water intrusion objective will be 
used to develop a hydrogeologic model for the region. This model will 
assist water managers (Water Replenishment District of Southern 
California and the Los Angeles County Department of Public Works) in 
providing a safe and uncontaminated ground-water supply to the local 
population.
    Important geologic information that the USGS will derive from this 
project's seismic-reflection data is how earthquake deformation is 
distributed offshore; that is, where the active faults are and what the 
history of movement along them has been. This should improve 
understanding of the shifting pattern of deformation that occurred over 
both the long term (approximately the last 100,000 years) and short 
term (the last few thousand years). The USGS seeks to identify actively 
deforming structures that may constitute significant earthquake 
threats. The USGS also proposes to locate offshore landslides that 
might affect coastal areas. Not only major subsea landslides might 
affect the footings of coastal buildings, but also very large slides 
can generate local tsunamis. These large sea waves can be generated by 
seafloor movement that is produced either by landslides or by 
earthquakes. Knowing where large slides have occurred offshore will 
help locate areas susceptible to wave inundation.
    Some faults that have produced earthquakes lie entirely offshore or 
extend into offshore areas where they can be studied using high-
resolution seismic-reflection techniques. An example is the Rose Canyon 
fault, which extends through the San Diego area, and is considered to 
be the primary earthquake threat. This fault extends northward from La 
Jolla, beneath the inner continental shelf, and appears again onshore 
in the Los

[[Page 39872]]

Angeles area. This fault and others like it near shore could generate 
moderate (M5-6) to large (M6-7) earthquakes.
    Knowing the location and geometry of fault systems is critical to 
estimating the location and severity of ground shaking. Therefore, the 
results of this project will contribute to decisions involving land 
use, hazard zonation, insurance premiums, and building codes.
    The USGS emphasizes that the goal is not to predict earthquakes but 
rather to help determine what steps might be taken to minimize the 
devastation should a large earthquake occur. The regional earthquake 
threat is known to be high, and a major earthquake could adversely 
affect the well-being of a large number of people. For example, 
earthquakes in the coastal ocean off southern California commonly 
result in large-scale submarine landslides, many of which could be 
capable of producing destructive tsunamis.
    The proposed work is in collaboration with scientists at the 
Southern California Earthquake Center, which analyzes faults and 
earthquakes in onshore regions, and with scientists at the Scripps 
Institute of Oceanography, who measure strain (incremental movement) on 
offshore faults.
    The USGS also wants to collect high-resolution seismic- reflection 
data to locate the sources and pathways of seawater that intrudes into 
freshwater aquifers below San Pedro. Ground water usage in the Los 
Angeles basin began in the mid-1800s. Today, more than 44,000 acre-feet 
of freshwater each year are extracted from the aquifers that underlie 
the West Coast Basin. Aggressive extraction of freshwater from coastal 
aquifers causes offshore salt water to flow toward areas of active 
pumping. To limit this salt-water intrusion, the Water Replenishment 
District and water purveyors in San Pedro are investing $2.7 million 
per year at the Dominguez Gap Barrier Project to inject freshwater 
underground to establish a zone of high water pressure in the aquifers 
near San Pedro and Long Beach. The resulting zone of high pressure 
forms a barrier between the invasive saltwater and the productive 
coastal aquifers.
    USGS scientists in San Diego are working with the Los Angeles 
County Department of Public Works and the Water Replenishment District 
to develop a ground-water simulation model to predict fluid flow below 
San Pedro and nearby parts of the Los Angeles Basin. This model will 
eventually be used in managing water resources. The accuracy of the 
present model, however, is compromised by a paucity of information 
about aquifer geometry and about other geologic factors that might 
affect fluid flow. Data collected by the USGS will be used to improve 
three-dimensional, fluid-flow models to aid management of water 
resources.

Proposed Field Work

    Fieldwork described here will be the fourth geophysical survey on 
the west coast that the USGS has conducted under close supervision by 
marine-mammal biologists. In March 1998, the USGS used a large (6,500 
in3., 106 liters) airgun array in and around Puget Sound to 
study the regional earthquake hazard (see 63 FR 2213, January 14, 
1998). The USGS employed 12 biologists, who worked on two ships 
continuously to oversee the seismic- reflection operations. On several 
occasions the USGS shut off the acoustic sources when marine mammals 
entered safety zones that had been stipulated by NMFS, and when mammals 
left these zones, the USGS gradually ramped-up the array as required in 
its permit to avoid harming wildlife. Marine-mammal biologists reported 
that during the survey, no overt distress was evident among the dense 
marine mammal population, and afterward no unexplained marine mammal 
strandings occurred.
    In August 1998, the USGS surveyed offshore from southern 
California, using a small airgun (40 in3, 0.65 liters). Two 
marine-mammal biologists oversaw this activity. In June 1999, the USGS 
conducted the third survey to support study of aquifer contamination 
and earthquake hazards in southern California (see 64 FR 31548, June 
11, 1999). Three marine-mammal biologists provided oversight for this 
operation. The survey described in this document is proposed to be 
conducted with similar oversight.

Experimental Design

    Marine studies conducted by the USGS focus on areas where saltwater 
intrusion into coastal aquifers is an active concern and where other 
kinds of natural hazards have their greatest potential impact on 
society. In southern California, USGS studies will focus on five chief 
geographic areas. First is the San Pedro shelf, offshore of the 
Dominguez Gap barrier project. Collecting data as close to shore as 
feasible is critically important in order to merge onshore and offshore 
geology in a manner that allows modeling the hydrologic flow through 
the system. With respect to the seismic-hazard issues in the offshore, 
the USGS' main priority (and second geographic area) is the coastal 
zone and continental shelf between Long Beach and San Diego, where much 
of the hazard appears to be associated with strike-slip faults such as 
the Newport-Inglewood and Palos Verdes faults. A critical component of 
the survey concerns the third geographic area, which lies farther 
offshore in the Santa Monica, San Pedro, and San Diego Trough deeps, 
where rapid sedimentation has left a more complete record, relative to 
shallow-water areas, that can be used to decipher earthquake history. 
The fourth area is the extension into the Santa Barbara Channel of 
major elements of onshore geology that cross the northern part of Santa 
Monica Bay and include several major known earthquake faults. The fifth 
area is the geologic boundary, marked generally by the Channel Islands, 
between the inner California Borderland (dominated by strike-slip 
faults) and the Santa Barbara Channel (dominated by compressional 
faults). This change in fault types is important to study because the 
degree of earthquake threat varies with fault type. The study proposed 
herein focuses on the three highest priority areas, which lie near 
shore between Los Angeles and San Diego.
    The seismic-reflection survey is planned to last 21 days. Based on 
experience collecting seismic-reflection data in this general area 
during 1998 and 1999, the USGS would prefer to conduct the 2000 survey 
in June. Because it will have to contract for a vessel from which to 
conduct the geophysical survey, the targeted study time frame is 
sometime within the May through July window. The basis for this 
decision is the USGS' desire to avoid the gray whale migrations and the 
peak arrival of other mysticetes during the later summer. An important 
part of the effort this summer will be to fill in gaps caused by 
shutdowns and daylight-only operations during earlier surveys.
    The USGS has not yet determined the exact tracklines for the 
survey, but it does know the areas where minisparker use will be 
concentrated (see Fig. 3 in the application). Within the overall work 
area, the objective is to collect seismic-reflection data along a grid 
of lines that are about 2 km (1.07 nmi) apart. Data collected during 
the 1998 and 1999 surveys will be used to guide the planning for the 
proposed survey in order to minimize the number of survey lines that 
are required to adequately define the aquifer geometries and location 
of potential earthquake faults.
    The USGS proposes to use two seismic-reflection systems for data 
collection: (1) A 1.5 kilo-Joule (kJ) minisparker using a 200-m (656.2-
ft) long multichannel streamer, and (2) a low-power, high resolution 
deep-tow

[[Page 39873]]

system. The potential effect on marine mammals is from the minisparker; 
mammals cannot become entangled in the streamer. The low-powered, high-
resolution seismic- reflection system, manufactured by Huntec, Ltd., 
will obtain detailed information about the very shallow geology. The 
seismic-reflection systems will be aboard a vessel owned by a private 
contractor or academic cooperator. Ship navigation will be accomplished 
using satellites of the Global Positioning System. The survey ship will 
be able to report accurate positions, which is important to mitigating 
the minisparker's effect on marine mammals and to analyzing what 
impact, if any, minisparker operation has on the environment.

The Seismic Sound Sources

    The primary sound source to be used during this survey will be a 
1.5 kJ ``SQUID 2000'' minisparker system manufactured by Applied 
Acoustic Engineering, Inc. This minisparker includes eight electrodes 
that are mounted on a small pontoon sled. The electrodes simultaneously 
discharge electric current through the seawater to an electrical 
ground. This discharge creates an acoustic signal. The pontoon sled 
that supports the minisparker is towed on the sea surface, 
approximately 20 meters (65.6 ft) behind the ship.
    Source characteristics of the SQUID 2000TM minisparker 
provided by the manufacturer show a sound-pressure level (SPL) of 209 
dB re 1 Pa-m root-mean-square (RMS). The amplitude spectrum of 
this pulse indicates that most of the sound energy lies between 150 
hertz (Hz) and 1700 Hz (1.7 kHz), and the peak amplitude is at 900 Hz. 
The output sound pulse of the minisparker has a duration of about 0.8 
milli-seconds (ms). When operated at sea for the multichannel seismic-
reflection survey proposed herein, the minisparker will be discharged 
every 4 to 6 seconds.
    The second seismic source that will be used during this survey is a 
HuntecTM system, which generates underwater sound at higher 
frequencies than does the minisparker. The HuntecTM system 
uses electromagnetically driven plates to produce an acoustic pulse 
every 0.5 seconds, with a duration of about 0.3 ms. In water depths 
greater than 200 m (656.2 ft), the HuntecTM source is towed 
behind the ship at a depth of approximately 100 m (328.1 ft). In 
shallow water, such as the inner shelf, the sound source is towed at a 
depth of about 5 m (16.4 ft) of the sea surface within about 5 m (16.4 
ft) of the stern of the ship. The SPL for this source is 205 dB re 1 
Parms. The frequencies of the main output sound are 
between 500 Hz and 8 kHz, with a peak amplitude at 4.5 kHz.

Comments and Responses

    A notice of receipt of the application and proposed authorization 
was published on March 28, 2000 (65 FR 1374), and a 30-day public 
comment period was provided on the application and proposed 
authorization. Comments were received from the Marine Mammal Commission 
(MMC).
    Comment 1: The MMC notes that the description of the two sound 
sources contained in the Federal Register document appears somewhat 
different than the description contained in the application. For 
example, the description of the minisparker does not mention a 200-m 
(656.2-ft) streamer, that the HuntecTM system is towed 
approximately 100 m (328.1 ft) behind the ship in water depths greater 
than 200 m (656.2 ft), and that only the minisparker will be towed at 
night.
    Response: The description of the acoustic sources is more clearly 
described in this document. The streamer is only used as a receiver and 
is not a sound source. The streamer will be deployed during any 
operation involving the minisparker sound source. In shallow water, 
which will be the major part of the survey this year, because of the 
approval to work within the 3-mile (5.6 km) limit using the minisparker 
sound source, the HuntecTM system will be towed just below 
or at the sea surface and typically will be within 5 m (16.4 ft) of the 
minisparker sound source. Thus, during night operations in shallow 
water, both systems will be in the same illuminated safety zone.
    Comment 2: The MMC notes that the area of the planned survey, while 
not likely to encounter California sea otters as noted in the 
application, may encounter Guadalupe fur seals. If California sea 
otters may be encountered, the applicant should apply to the U.S. Fish 
and Wildlife Service for an incidental harassment authorization. If 
Guadalupe fur seals could be encountered, this species should be 
included in any incidental harassment authorization issued by NMFS.
    Response: California sea otters, which are typically found north of 
Point Conception, are not expected to be observed within the limits of 
the proposed survey. The USGS has reviewed the reports of the marine 
mammal observers from Cascadia Research Collective in Olympia, WA 
(Cascadia) for its surveys in 1998 and 1999 and noted that sea otters 
were not sighted during either operation. Also for those same years, 
there are no reported sightings of Guadalupe fur seals. While the 
Guadalupe fur seal population has been increasing on Guadalupe Island, 
Mexico, their only breeding location, from below 1000 in the late 1970s 
to the current estimate of 7500, their breeding season is from May-
July, so it is very likely that most Guadalupe fur seals will be found 
further south, and not off southern California. However, there was a 
recent report of a mother-pup on San Miguel Island, from June-
September, 1997. Melin & DeLong (1999) speculate that it may have been 
due to El Nino conditions, as there are more strandings of Guadalupe 
fur seals along the Calfornia coast during El Nino years. Therefore, 
although the numbers of Guadalupe fur seals are increasing, and they 
seem to be extending their range at least during warmer years, because 
the seismic-reflection surveys are going to be taking place during the 
breeding season, the likelihood of a Guadalupe fur seal being in the 
area is extremely low.
    Comment 3: The MMC questions whether the planned nighttime 
observations would be capable of assuring that the surveys have the 
least practicable adverse impact on marine mammals if the 
HuntecTM system is used at night, or if the 200-m (656.2-ft) 
streamer is part of the minisparker sound source. Concerned that night-
time lighting for marine mammal observations could attract fish and 
squid, which in turn may attract and increase the likelihood of 
attracting marine mammals, the MMC recommends that NMFS consult with 
the applicant to assure that any marine mammals approaching or entering 
the designated safety zone around the sound source(s) can be detected 
in time to stop operations so the animals are not adversely affected.
    Response: In order for seismic reflection surveys to incidentally 
take marine mammals at night, the night-time lighting must be capable 
of making the entire safety zone visible. If lighting attracts marine 
mammals, then the USGS would incur more shutdowns and a longer period 
of time would be needed to complete the surveys. NMFS is unaware of 
ship lighting attracting fish and squid to the extent that marine 
mammals would likewise be attracted to the vessel. The mitigation plan 
for the USGS survey is being designed by Cascadia in order to ensure 
that shutdowns are conducted when marine mammals are about to enter the 
safety zone. The IHA requires the USGS to have a minimum of 3 observers 
available at all times, with two on watch

[[Page 39874]]

at all times that seismic operations are starting up or underway.
    NMFS notes that the recent precautionary application of a 180-dB 
safety zone for protecting marine mammals does not necessarily mean 
that animals entering that zone will be adversely affected. It simply 
means that animals have the potential to incur a temporary elevation in 
hearing threshold (termed temporary threshold shift (TTS)), lasting, at 
worst, for a few minutes at the 180 dB sound pressure level. Also, 
based upon California Coastal Commission (CCC) determinations, the USGS 
has implemented, and NMFS has adopted for this action, a safety zone 
for pinnipeds based on the 180 dB isopleth. However, current scientific 
consensus indicates that a safe level for impulse sounds for pinnipeds 
from incurring TTS is higher than the level indicated for cetaceans 
(e.g., 180 dB). As a result, although scientists have preliminarily 
established an SPL of 190 dB re 1 Pa-mRMS as a safe 
level for pinnipeds underwater, and while NMFS adopts this information 
as the best scientific information available, the USGS must abide by 
the conditions contained in its CCC consistency determination. 
Therefore, NMFS believes that the potential for adversely affecting 
pinnipeds is even less likely as they would need to be significantly 
closer to the source than provided by the safety zone.
    Comment 4: The MMC notes that the USGS application did not indicate 
the species or numbers of marine mammals that approached or entered the 
designated safety zones during the 1998 and 1999 surveys. The MMC 
recommends, as it did on the USGS' 1999 application, that the USGS be 
required to (1) report at the end of each 24-hour period the species 
and number of marine mammals observed approaching and entering the 
designated safety zone during the day and during the night; and (2) 
suspend night-time operations if the species or number of animals 
observed approaching and entering the designated safety zone at night 
are significantly different than those observed during the day, 
suggesting that nighttime observations were failing to detect 
significant numbers of animals that enter the safety zones and could be 
killed or injured.
    Response: There are several issues involved in this recommendation 
that need to be addressed separately. First, marine mammals are very 
unlikely to be seriously injured, let alone killed, by the relatively 
low-intensity acoustic sources proposed by the USGS for this survey. 
Although at different frequencies, the seismic equipment proposed for 
use by USGS are less powerful than fish-finding sonars commonly used in 
U.S. waters (including California), and there is no evidence to date 
that commercially available sonars are adversely affecting marine 
mammals.
    Second, it may not be possible for the USGS to make daily reports. 
The USGS' leased vessel does not have satellite communication 
facilities and the only communication method available would be cell 
phone, but only when the vessel is within range of an onshore repeater.
    NMFS doesn't believe daily reports are necessary for this 
authorization because, based on the Cascadia observations during the 
previous surveys, the number of mammals that enter the safety zone is 
small; there were only 11 occurrences in 1998 and 21 in 1999. It is 
also important to note that the designated safety zones were 
significantly larger (as much as 200 m (656.2 ft), depending upon the 
species in question) during those earlier surveys. The number of 
occurrences for the proposed survey this year is expected to be lower 
given the 30 m (98.4 ft) safety zone for the much less powerful sound 
source that will be employed. Cascadia will report all marine mammal 
observations. This report will be available upon completion of the 
survey (see Reporting).
    The second part of the recommendation from the MMC is difficult to 
evaluate. First, merely comparing numbers of occurrences between night 
and day has the built-in assumption that the density of marine mammals 
is uniform throughout the survey area. A review of the area of the 
shutdowns required by the Cascadia observers during the previous 
surveys shows that the shutdowns are commonly grouped in a few 
geographic areas, probably reflecting such factors as feeding success 
by the mammals. In 1999, when there were 21 shutdowns for mammals 
moving within the designated safety zone, six occurred on one day but 
there were no shutdowns during several of the survey days.
    In this regard, it should also be noted that Cascadia reported for 
the 1999 survey that eight of the 21 occurrences that required shutdown 
of the sound sources involved common dolphins (Delphinus delphis) 
approaching the seismic boat to bowride. More specifically, the report 
stated that: ``Marine mammal movements and behaviors observed during 
the seismic-reflection operations, revealed no apparent patterns of 
avoidance and none could be interpreted as harassment.'' Again, given 
the 30-m (98.4-ft) safety zone for the much less powerful sound source 
that will be used this year, the number of occurrences of shutdowns for 
the proposed survey should be significantly less.
    Finally, the CCC did not approve night operations for the 1999 
survey, so the USGS does not have data concerning day vs. night 
operations from that year. In 1998, when there were night operations, 
Cascadia observers required 11 shutdowns. Three of these shutdowns were 
due to pinnipeds, and these occurrences were in mid-day. Of the 
remaining eight shutdowns, three occurred at night. Because the hours 
of daylight were about double the hours of darkness during the time of 
the survey, there did not appear to be any significant difference 
between night and day operational shutdowns during the 1998 survey.
    Comment 5: Noting that the work proposed by the USGS is a multi-
year effort, the MMC recommends that NMFS consult with the applicant to 
determine whether it would be more appropriate to obtain an 
authorization under section 101(a)(5)(A) of the MMPA for the full range 
of studies proposed rather than annual authorizations under section 
101(a)(5)(D) of the MMPA.
    Response: NMFS believes that a multi-year authorization under 
section 101(a)(5)(A) of the MMPA warrants the extensive time and effort 
to implement regulations and annual Letters of Authorization thereunder 
only when the activity does not have the potential to vary 
significantly on an annual basis and/or when the impacts are fairly 
uniform. For example, activities such as construction and production of 
an oil production facility at Northstar (64 FR 57010, October 22, 1999) 
or the taking of seals at Seabrook Nuclear Power Station (64 FR 28114, 
May 25, 1999) meet these two criteria. On the other hand, whenever an 
activity is likely to require its authorization issued under section 
101(a)(5)(A) to be publically reviewed annually (such as occurred with 
seismic oil and gas exploration in the Beaufort Sea prior to 1994), 
little would be gained by delaying an authorization for several months 
while regulations are issued prior to an authorization under section 
101(a)(5)(A) of the MMPA. This lengthy delay in issuing incidental take 
authorizations due to the inordinate length of time necessary for 
rulemaking actions was the primary reason Congress implemented MMPA 
section 101(a)(5)(D) authorizations when the takings were limited to 
incidental harassment. Since the CCC has instructed the USGS that each 
operation

[[Page 39875]]

must be considered separately because of the different geographic areas 
and different times of the year that the surveys may be conducted, no 
benefit would be gained by issuing regulations governing this 
activity's incidental take.
    Comment 6: The MMC notes statements made in the application and 
Federal Register document (65 FR 1374, March 28, 2000), that pinnipeds 
will come from great distances to scrutinize seismic operations, and 
that as a result, NMFS will not require the minisparker to be shut down 
if pinnipeds approach the safety zone. The MMC states that there is no 
indication whether the referenced observations are anecdotal or the 
product of peer-reviewed science. If not peer-reviewed, the MMC 
suggests that research should be conducted under section 104 of the 
MMPA.
    Response: The proposed mitigation measure noted in the Federal 
Register document (65 FR 1374, March 28, 2000), states that for 
pinnipeds, if the research vessel towing the minisparker approaches a 
pinniped, a safety radius of 30 m (98 ft) around the seismic source 
when operating in deep water and 15 m (49.2 ft) when in shallow water 
will be maintained. However, if a pinniped approaches the towed 
minisparker source, NMFS proposes to not require the USGS to shutdown 
the minisparker, but to require the USGS to monitor the interaction to 
ensure the animal does not show signs of distress. If the pinniped(s) 
show obvious distress, the USGS will terminate minisparker operations 
and will continue to conduct observations on effects the minisparker 
may have on the animals. Reviewers should note that these seals and sea 
lions need to be actively approaching the vessel (itself moving forward 
at about 3-5 knots) from the side of the vessel or the stern, meaning 
that the animal is voluntarily approaching a noise source that is 
increasing in strength as the animal gets closer.
    It is NMFS' responsibility to ensure that the incidental taking is 
reduced to the lowest level practicable. In reviewing the information 
available, NMFS has determined that it is not practicable to require 
applicants to delay seismic surveys in order to provide additional 
protection for curious seals. These delays lengthen the time necessary 
for completing surveys, requiring additional survey time and resulting 
in a potential increase in impacts on more sensitive marine mammal 
species, and raise the potential for increased costs for conducting 
surveys. As mentioned in this document and in prior Federal Register 
notices, seals and sea lions are believed to be less likely to be 
harmed by underwater noise than cetaceans, and have even been observed 
swimming in the bubbles of seismic airguns, a source significantly more 
powerful than the proposed instruments.
    While, to our knowledge, the information provided has not been 
peer-reviewed or scientifically verified under a section 104 scientific 
research permit, these observations were, for the most part, obtained 
as a result of monitoring seismic activities. As a result, NMFS does 
not consider them anecdotal. NMFS has chosen to adopt observations made 
to date, some of which were conducted under previous MMPA section 
101(a)(5)(D) authorizations, as the best scientific information 
available.

Description of Habitat and Marine Mammals Affected by the Activity

    The Southern California Bight supports a diverse assemblage of 29 
species of cetaceans (whales, dolphins and porpoises) and 6 species of 
pinnipeds (seals and sea lions). The species of marine mammals that are 
likely to be present in the seismic research area include the 
bottlenose dolphin (Tursiops truncatus), common dolphin, killer whale 
(Orcinus orca), Pacific white-sided dolphin (Lagenorhynchus 
obliquidens), northern right whale dolphin (Lissodelphis borealis), 
Risso's dolphin (Grampus griseus), pilot whales (Globicephala 
macrorhynchus), Dall's porpoise (Phocoenoides dalli), sperm whale 
(Physeter macrocephalus), humpback whale (Megaptera novaengliae), gray 
whale (Eschrichtius robustus), blue whale (Balaenoptera musculus), 
minke whale (Balaenoptera acutorostrata), fin whales (Balaenoptera 
physalus), harbor seal (Phoca vitulina), elephant seal (Mirounga 
angustirostris), northern sea lion (Eumetopias jubatus), and California 
sea lion (Zalophus californianus), northern fur seal (Callorhinus 
ursinus) and sea otters (Enhydra lutris). General information on these 
latter species can be found in the USGS application and in Forney et 
al. (1999) and Barlow et al. (1998, 1997). Please refer to these 
documents for information on the biology, distribution, and abundance 
of these species in southern California waters.

Potential Effects of Seismic Surveys on Marine Mammals

Discussion

    Seismic surveys are used to obtain data about stratigraphic 
sequences and rock formations up to several thousands of feet deep. 
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.
    Disturbance by seismic noise is the principal means of taking by 
this activity. Vessel noise may provide a secondary source. Also, the 
physical presence of vessel(s) could lead to some non-acoustic effects 
involving visual or other cues.
    Depending upon ambient conditions and the sensitivity of the 
receptor, underwater sounds produced by open-water seismic operations 
may be detectable some 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. An incidental harassment take is presumed to 
occur when marine mammals in the vicinity of the seismic source (or 
vessel) react to the generated sounds or to visual cues.
    Seismic pulses are known to cause some species of whales, including 
gray whales, to behaviorally respond within a distance of several 
kilometers (Richardson et al., 1995). Although some limited masking of 
low-frequency sounds is a possibility for those species of whales using 
low frequencies for communication, the intermittent nature of seismic 
source pulses limits the extent of masking. Bowhead whales in Arctic 
waters, for example, 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).
    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-dive-
respiration 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.
    Hearing damage is not expected to occur during the project. While 
it is not known whether a marine mammal co-located or very close to an 
intense seismic source would be at risk of permanent hearing 
impairment, TTS is a theoretical possibility for animals close to the 
seismic-reflection sources.

[[Page 39876]]

However, planned monitoring and mitigation measures (described later in 
this document) are designed to detect marine mammals occurring near the 
seismic-reflection source(s) and to avoid, to the greatest extent 
practicable, exposing them to sound pulses that have any possibility of 
causing TTS in hearing.

Maximum Sound-Exposure Levels for Marine Mammals

    The adverse effects of underwater sound on mammals have been 
documented for exposure times that last for tens of seconds or minutes, 
but adverse effects have not been documented for the brief pulses 
typical of the minisparker (0.8 ms) and the HuntecTM system 
(typically 0.3 ms). While NMFS in the past considered that the maximum 
SPLs, from impulse sounds, to which marine mammals could safely be 
exposed were 180 dB re 1 Pa-mrms for mysticetes 
(baleen whales) and sperm whales, and 190 dB re 1 Pa-
mrms for odontocetes (toothed whales, dolphins and 
porpoises) and pinnipeds (seals and sea lions), recent workshops have 
recommended a more precautionary approach be taken and, accordingly, 
NMFS now recommends that odontocetes also be limited to an SPL no 
greater than 180 dB re 1 Pa-mrms. However, based on 
statements and recommendations made at NMFS' Acoustic Criteria Workshop 
in 1998, NMFS has not increased its recommended safety zone for 
pinnipeds to this same level. In 1999 and 2000, the CCC has limited the 
maximum sound-exposure level to 180 dB re 1 Pa-m for all 
species of marine mammals.
    In its application, the USGS has provided two estimates of how 
close marine mammals can approach the HuntecTM and 
minisparker sources before they need to be powered down. The first 
estimate follows the procedure required by the CCC in 1999, where 
underwater sound is assumed to attenuate with distance according to the 
equation 20log(Radius(R)), and the maximum SPL to which marine mammals 
can be exposed is 180 dB re 1 Pa-mRMS. The 
alternative estimate of safe distance is proposed for operations 
limited to shallow water. In shallow water, sound from both the 
HuntecTM and minisparker sources will decay (attenuate) with 
distance more sharply than 20log(R) because some of the sound energy 
will exit the water and penetrate the sea floor when the source is 
physically close to the sea floor.
    In the deeper water (greater than 50 m (164 ft)) areas of the 
proposed survey, the safety zone for the HuntecTM and 
minisparker is a circle whose radius is the distance from the source to 
where the SPL is reduced to 180 dB re 1 Pa-mRMS. 
For a 20log(R) sound attenuation, the safety zone for a 209 dB re 1 
Pa-mRMS source has a radius of about 30 m (98 ft).
    Much of that part of the proposed 2000 survey that focuses on 
saltwater intrusion of coastal aquifers will be conducted close to 
shore, where water is shallow. In 1999, the USGS measured a sound 
attenuation of 27log(R) in shallow water off southern California. 
Therefore, the USGS proposes that for inshore areas, underwater sound 
will attenuate to approximately 25log(R), which for inshore areas would 
yield a safety zone with a radius of 15 m (49.2 ft).
    Because observers would be able to monitor this short radius of a 
15 m (49.2 ft) or 30 m (98 ft) safety zone, the USGS also proposed that 
the HuntecTM and minisparker can be used at night, using 
spotlights to illuminate the safety zone around the tow sled.

Estimated Number of Potential Harassments of Marine Mammals

    Based on estimated marine mammal populations within the survey area 
(Calambokidis and Francis, 1994) and on the number of individuals that 
were observed during the 1998 and 1999 seismic surveys, the USGS 
estimates that up to 50 blue whales, 5 killer whales, 10 minke whales, 
10 sea otters, 50 humpback whales, 50 northern sea lions, 100 northern 
fur seals, 100 northern elephant seals, 100 Dall's porpoise, 100 
Risso's dolphins, 100 northern right-whale dolphins, 100-200 Pacific 
white-sided dolphins, 100 bottlenosed dolphins, 200 California sea 
lions, 200 Pacific harbor seals, and 10,000-12,000 common dolphins may 
be harassed incidental to the USGS survey. No marine mammals will be 
seriously injured or killed as a result of the survey. However, NMFS 
has subsequently reviewed the information and has determined that the 
large mysticete whales, northern sea lions, and sea otters are unlikely 
to be affected by either acoustic source planned to be used this year 
in this area by the USGS. The large whales are expected to remain in 
offshore waters outside the Channel Islands at the time of the year 
that the activity will take place; northern sea lions, which are 
expected to be in more northerly waters during the summer, are not 
known to be affected by low frequency seismic sources unless close to 
the source; and California sea otters will be north of Point 
Conception.

Mitigation of Potential Environmental Impact

    To avoid potential Level A harassment (i.e., injury) of marine 
mammals, safety zones will be established and monitored continuously by 
biologists, and the USGS will shut off any operating seismic source 
whenever the ship and a marine mammal converge closer than the 
previously mentioned safety distances.
    For all cetaceans (whales, dolphins, and porpoises), NMFS is 
requiring USGS to immediately cease operations of the minisparker when 
members of these species approach within 30 m (98 ft) of the sound 
source when operating in deep water, and 15 m (49.2 ft) for both the 
minisparker and the HuntecTM source when operating in 
shallow water. (The HuntecTM source in deep water will be in 
waters significantly deeper than the radius of the safety zone and 
therefore is not practical to monitor). NMFS understands that the CCC 
has not accepted the scientific data that in shallow water, underwater 
sound commonly attenuates more sharply than 20log(R), for reasons 
mentioned previously in this document. However, NMFS is required to use 
the best scientific information available when making determinations 
and implementing appropriate mitigation measures, and as such, has 
concluded that the more restrictive conditions placed on the USGS by 
the CCC are not supportable and therefore cannot be adopted by NMFS. 
This however, in no way relieves the USGS from complying with the 
conditions imposed by the CCC in its determination of coastal 
consistency.
    For pinnipeds (seals and sea lions), if the research vessel 
approaches a pinniped, the USGS originally requested, and, for the 
reasons cited in the previous paragraph, NMFS has accepted, that a 
safety radius of 30 m (98 ft) around the minisparker seismic source 
when operating in deep water and 15 m (49.2 ft) for both acoustic 
sources when in shallow water will be maintained. NMFS believes the 180 
dB re 1 Pa-mRMS safety zone is more conservative 
than is necessary for the reasons stated previously in this document, 
however, because this level was requested initially by the applicant, 
NMFS has accepted this condition for the USGS' IHA.
    However, if a pinniped approaches the towed acoustic source, NMFS 
will not require the USGS to shutdown the source, but will require the 
USGS to monitor the interaction to ensure the animal does not show 
signs of distress. Experience indicates that pinnipeds will

[[Page 39877]]

come from great distances to inspect seismic operations. Seals have 
been observed swimming within airgun bubbles, 10 m (33 ft) away from 
active arrays, apparently unaffected. Although seismic-reflection 
operations will be terminated if the pinnipeds show obvious distress, 
the USGS is required to conduct observations on effects the acoustic 
sources may have on the animals.
    The USGS will have marine biologists aboard the ship who will have 
the authority to stop the seismic-reflection operations when a marine 
mammal enters the safety zone or indicates obvious distress anywhere 
within the vicinity of the ship. Although NMFS believes it is very 
unlikely to occur, if observations are made that one or more marine 
mammals of any species are attempting to beach themselves when the 
source is operating in the vicinity of the shore, the seismic-
reflection sources will be immediately shut off and NMFS contacted.
    During seismic-reflection surveying, the ship's speed will only be 
4 to 5 knots, so that when the acoustic source is being discharged, 
nearby marine mammals, if they hear the low- to mid- frequency noise, 
will have gradual warning of the vessel's approach and can move away if 
disturbed. Finally, NMFS will coordinate with the local stranding 
network to determine whether any strandings which occur during, or near 
the time of the survey, can be related to the seismic-reflection 
operation. If NMFS determines, based upon a necropsy of the animal(s), 
that the death was likely due to exposure to the USGS acoustic 
source(s), the survey will cease until procedures are altered to 
eliminate the potential for future mortality.
    Operating less than 24 hours each day incurs substantially 
increased cost for the leased ship, which the USGS states that it 
cannot afford. The ship schedule provides a narrow time window for this 
project; other non-related experiments are already scheduled to precede 
and follow this survey and for that reason, the USGS cannot arbitrarily 
extend the survey time. Thus, the USGS does not propose as a mitigation 
measure shutting down in dark or during periods of poor visibility. The 
2000 survey will require only 3 weeks, and it will be spread out 
geographically from Los Angeles to San Diego, so no single area will 
experience long-term activity. In the view of the USGS, the best course 
is to complete the survey as expeditiously as possible. For these 
reasons, the USGS has requested that the acoustic survey be conducted 
24 hours/day and the IHA allow 24-hour operations, specifically at 
night and with the understanding that the USGS will survey during this 
time in shallow water. Both NMFS and the CCC concur, and the IHA 
provides for 24-hour operations surveys while in shallow water.

Possible Modifications or Alternatives to the Proposed Survey

    Options to change the activity are limited. In order to reduce the 
probability for the incidental harassment of marine mammals and to be 
able to operate within nearshore areas, the USGS has changed from using 
a seismic airgun source, as used in prior surveys, to a minisparker for 
the proposed survey. The seismic-source strength cannot be reduced 
further in an attempt to limit the potential environmental impact. The 
minisparker is already smaller than any source the USGS has previously 
used for these kinds of geophysical surveys, and the problem with this 
option is that the USGS cannot significantly reduce the source strength 
without jeopardizing the success of this survey. This judgment is based 
not only on USGS' decades-long experience with seismic-reflection 
surveys, but especially on the 1998 survey that was conducted in the 
same general area as outlined here. If the USGS were to reduce the 
sound-source size and then fail to obtain the required information, 
another survey would need to be conducted, and this would have the 
potential to increase impact on marine mammals.
    To abandon this study altogether is a poor option. The USGS has 
described the societal relevance of this project as it would improve 
understanding of fluid movement in coastal aquifers and how to stem the 
intrusion of salt water into them. Another facet of this study is to 
help scientists understand the regional earthquake hazard that, in 
turn, will aid city planners in establishing building codes. If the 
project was canceled, such information would be unavailable.
    This project could be carried out at some other time of year. The 
USGS talked with biologists to find out the best time for the project 
to be conducted. The USGS wants to avoid the gray whale migrations and 
the mid-summer arrival of other mysticete species because, while these 
species remain mostly in the area of the Channel Islands, some 
individuals venture closer to the mainland. An important consideration 
in deciding the most appropriate time of the year is that biologists 
can best prevent harm to mammals when daylight is long, that is, near 
the solstice.

Monitoring

    Monitoring marine mammals while the acoustic sources are active 
will be conducted 24 hours each day. Trained marine mammal observers 
will be aboard the seismic vessel to mitigate the potential 
environmental impact from using these acoustic sources and to gather 
data on the species, number, and reaction of marine mammals to the 
sources. During daylight, observers will use 7x50 binoculars with 
internal compasses and reticules to record the horizontal and vertical 
angle to sighted mammals. Night-time operations will be conducted with 
a spotlight to illuminate the safety zone around the minisparker tow 
sled. Monitoring data to be recorded during seismic-reflection 
operations include the name of the observer on duty, and weather 
conditions (such as Beaufort sea state, wind speed, cloud cover, swell 
height, precipitation, and visibility). For each mammal sighting, the 
observer will record the time, bearing and reticule readings, species, 
group size, and the animal's surface behavior and orientation. 
Observers will instruct geologists to shut off the acoustic source(s) 
whenever a marine mammal enters the safety zone.

Reporting

    The USGS will contract with Cascadia to provide an initial report 
to NMFS within 160 days of the completion of the 2000 phase of the 
marine seismic project. This report will provide dates and locations of 
seismic operations, details of marine mammal sightings, and estimates 
of the amount and nature of all takes by harassment. A final technical 
report will be provided by USGS within 270 days of completion of the 
2000 phase of the marine seismic project. 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, NMFS has completed 
consultation on the issuance of an IHA. NMFS finds this action to be 
unlikely to adversely affect listed marine mammals because the 
endangered whales are expected to be more prevalent in offshore waters 
outside the Channel Islands at the time of the year that the activity 
will take place; northern sea lions, which are expected to be in more 
northerly waters during the summer, are not known to be affected by low 
frequency seismic sources unless close to the source; and the Guadalupe 
fur seal is expected to be on or near

[[Page 39878]]

Guadalupe Island, Mexico, during this time.

Conclusions

    NMFS has determined that the short-term impact of conducting marine 
seismic-reflection data in offshore southern California may result, at 
worst, in a temporary modification in behavior by certain species of 
pinnipeds and cetaceans. While behavioral modifications may be made by 
certain species of marine mammals to avoid the resultant noise from the 
seismic sources, this behavioral change is expected to have no more 
than a negligible impact on the animals.
    In addition, no take by serious injury or death is anticipated, and 
takes will be at the lowest level practicable due to the incorporation 
of the mitigation measures previously mentioned. No known 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.
    Since NMFS is assured that the taking would not result in more than 
the incidental harassment (as defined by the MMPA) of small numbers of 
certain species of marine mammals, would have only a negligible impact 
on these stocks, and would result in the least practicable impact on 
the stocks, NMFS has determined that the requirements of section 
101(a)(5)(D) of the MMPA have been met and the authorization can be 
issued.

Authorization

    Accordingly, NMFS has issued an IHA to the USGS for the possible 
harassment of small numbers of several species of marine mammals 
incidental to collecting marine seismic-reflection data off southern 
California between June 5 and September 30, provided the mitigation, 
monitoring and reporting requirements described in the authorization 
are undertaken.

    Dated: June 21, 2000.
Art Jeffers,
Deputy Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 00-16228 Filed 6-27-00; 8:45 am]
BILLING CODE 3510-22-F
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