[Federal Register Volume 77, Number 187 (Wednesday, September 26, 2012)]
[Notices]
[Pages 59211-59220]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-23749]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
[FWS-R8-FHC-2012-N194; FRES48010810420-L5-FY12]
Marine Mammals; Incidental Take During Specified Activities;
Proposed Incidental Harassment Authorization
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of receipt of application; request for comments.
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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), have
received an application from Pacific Gas and Electric Company (PG&E)
for authorization under the Marine Mammal Protection Act of 1972 (MMPA)
to take small numbers of southern sea otters (Enhydra lutris nereis) by
harassment, as those terms are defined in the statute and the Service
implementing regulations, incidental to a marine geophysical survey. In
accordance with provisions of the MMPA, we request comments on our
proposed authorization for the applicant to incidentally take, by
harassment, small numbers of southern sea otters for a period of 2.5
months beginning on October 15, 2012, and ending December 31, 2012. We
anticipate no take by injury or death and include none in this proposed
authorization, which would be for ``take by harassment'' only.
DATES: Comments and information must be received by October 26, 2012.
ADDRESSES: You may submit comments by any one of the following methods:
[[Page 59212]]
1. By U.S. mail or hand-delivery to: Diane Noda, Field Supervisor,
Ventura Fish and Wildlife Office, 2493 Portola Road, Suite B, Ventura,
CA 93003.
2. By fax to: 805-644-3958, attention to Diane Noda, Field
Supervisor.
3. By electronic mail (email) to: R8_SSO-IHA_Comment@FWS.gov.
Please include your name and return address in your message.
FOR FURTHER INFORMATION CONTACT: To request copies of the application,
the list of references used in this notice, and other supporting
materials, contact Lilian Carswell at the address in ADDRESSES, or by
email at Lilian_Carswell@fws.gov.
SUPPLEMENTARY INFORMATION:
Background
Sections 101(a)(5)(A) and (D) of the MMPA, as amended (16 U.S.C.
1371 (a)(5)(A) and (D)), authorize the Secretary of the Interior 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, provided that we make certain findings and either
issue regulations or, if the taking is limited to harassment, provide a
notice of a proposed authorization to the public for review and
comment.
We may grant authorization to incidentally take marine mammals if
we find that the taking will have a negligible impact on the species or
stock(s), and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for subsistence uses. As part
of the authorization process, we prescribe permissible methods of
taking and other means of affecting the least practicable impact on the
species or stock and its habitat, and requirements pertaining to the
monitoring and reporting of such takings.
The term ``take,'' as defined by the MMPA, means to harass, hunt,
capture, or kill, or to attempt to harass, hunt, capture, or kill, any
marine mammal. ``Harassment,'' as defined by the MMPA, means ``any act
of pursuit, torment, or annoyance which (i) has the potential to injure
a marine mammal or marine mammal stock in the wild [the MMPA calls this
Level A harassment], or (ii) 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 [the MMPA calls
this Level B harassment].''
The terms ``small numbers,'' ``negligible impact,'' and
``unmitigable adverse impact'' are defined in 50 CFR 18.27, the
Service's regulations governing take of small numbers of marine mammals
incidental to specified activities. ``Small numbers'' is defined as ``a
portion of a marine mammal species or stock whose taking would have a
negligible impact on that species or stock.'' ``Negligible impact'' is
defined 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.'' ``Unmitigable adverse impact'' is defined
as ``an impact resulting from the specified activity (1) that is likely
to reduce the availability of the species to a level insufficient for a
harvest to meet subsistence needs by (i) causing the marine mammals to
abandon or avoid hunting areas, (ii) directly displacing subsistence
users, or (iii) placing physical barriers between the marine mammals
and the subsistence hunters; and (2) that cannot be sufficiently
mitigated by other measures to increase the availability of marine
mammals to allow subsistence needs to be met.'' The subsistence
provision does not apply to the southern sea otters.
Section 101(a)(5)(D) of the MMPA established an expedited process
by which U.S. citizens can apply for an authorization to incidentally
take small numbers of marine mammals where the take will be limited to
harassment. Section 101(a)(5)(D)(iii) establishes a 45-day time limit
for Service review of an application, followed by a 30-day public
notice and comment period on any proposed authorizations for the
incidental harassment of marine mammals. Within 45 days of the close of
the comment period, we must either issue or deny issuance of the
authorization. We refer to these authorizations as Incidental
Harassment Authorizations (IHAs).
Summary of Request
On August 31, 2012, we received a revised request from PG&E
(applicant) for MMPA authorization to ``take by harassment'' southern
sea otters (Enhydra lutris nereis) incidental to a High Energy Seismic
Survey (HESS) in the vicinity of the Diablo Canyon Power Plant (DCPP)
and known offshore fault zones near DCPP in San Luis Obispo County,
California. An initial request was received June 28, 2012. The project
is a collaborative effort between PG&E and the Lamont-Doherty Earth
Observatory (LDEO), a part of Columbia University. The project would
consist of deploying a seismic sound source offshore and receivers at
both onshore and offshore locations to generate data that could be used
to improve imaging of major geologic structures and fault zones in the
vicinity of the DCPP. Project activities are necessary to comply with
the requirements established by California State Assembly Bill 1632 and
directives of the California Public Utilities Commission to determine
whether there is any relationship between the known faults and to
enhance knowledge of offshore faults that are located in proximity to
the Central California Coast and DCPP. Estimating the limits of future
earthquake ruptures is particularly important in light of the close
proximity of the Hosgri Fault Zone to DCPP, one of California's major
nuclear power plants.
The applicant would conduct the geophysical survey with a seismic
research vessel (R/V Marcus G. Langseth), owned by the National Science
Foundation (NSF), and support/monitoring vessels, within two partially
overlapping survey box areas located between Estero Bay and the Santa
Maria River mouth (survey box area 3 was initially proposed but has
been removed from the project, and survey box area 1 was initially
proposed for 2012 but is now proposed to be conducted in 2013; because
IHAs are valid for no more than 1 year, only survey box areas 2 and 4
are considered under this authorization). Should the applicant request
incidental harassment authorization for survey box area 1 in 2013, the
Service will reanalyze the small number and negligible impact
determinations, which would include evaluation of the information
gained through the monitoring and reporting requirements proposed in
this IHA, and make a new finding at that time. The survey boxes would
consist of multiple parallel transect lines spaced approximately 200
meters (m) (656 feet (ft)) apart for survey box area 2 and
approximately 300 m (984 ft) apart for survey box 4. The average line
lengths and transit times for survey box areas 2 and 4 are given in
Table 1.
[[Page 59213]]
Table 1--Geophysical Survey Box Line Lengths and Durations
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Total time for
Line transit Average line one survey
Survey box Average line length time (hours) change time circuit
(hours) (hours)
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2..................................... 49.09 km (30.5 mi)...... 5.89 1.58 14.94
4..................................... 11.57 km (7.19 mi)...... 1.39 2 6.78
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The geophysical survey vessel would tow a series of sound-
generating air guns and sound-recording hydrophones along pre-
determined shore-parallel and shore-perpendicular transects to conduct
deep seismic reflection profiling of major geologic structures and
fault zones in the vicinity of DCPP. The air gun array would be towed
at a depth of 9 m (30 ft) and consist of 18 air guns with a total air
discharge volume of approximately 3,300 inch (in)\3\. The sound would
be generated by the discharge of the air guns once every 15-20 seconds,
approximately every 37.5 m (123 ft), assuming a vessel speed of 8.3
kilometers (km)/hour (hr) (4.5 knots).
The nearshore actions would include the placement of 12 seafloor
geophones (e.g., Fairfield Z700 nodal units) in nearshore water areas
(to approximately the 70 m [300 ft] isobath).The proposed deep (10 to
15 km or 6 to 9 miles [mi]) below ground survey High Energy Seismic
Survey (HESS) (energy > 2 kilo joule) would complement previously
completed shallow (<1 km [<0.6 mi] below ground surface) low energy (<2
kilo joule) 3D seismic reflection surveys.
A detailed description of the proposed action is contained in the
Draft Environmental Assessment (Draft EA) for Marine Geophysical
Surveys by the R/V Marcus G. Langseth for the Central Coastal
California Seismic Imaging (Padre Associates, Inc. 2012), and the
revised Incidental Harassment Authorization (IHA) Application (Padre
Associates, Inc. 2012) submitted to the National Marine Fisheries
Service (NMFS) and the Service on August 31, 2012.
Description of the Activity
Marine Geophysical Surveys by the R/V Marcus G. Langseth for the
Central Coastal California Seismic Imaging Project (project), San Luis
Obispo County, California.
a. Timing of Activities
The surveys are proposed to be conducted from October 15 through
December 31, 2012, to avoid the period of highest marine mammal and
fish migration activity and to accommodate nesting bird constraints.
Mobilization could begin as early as October 15, but sound source
verification procedures and active air gun surveys would start no
earlier than November 1. The surveys would occur 24 hours per day, 7
days per week. The project duration would be approximately 49 days,
with the seismic survey comprising approximately 23 of those days, and
the remaining days occupied in project preparation, transit, and
anticipated weather and/or ship maintenance delays.
The proposed survey includes a total survey line length of 3,565.8
km (2,215.7 mi), of which 46.4 km (28.8 mi) of survey transect lines
would be traveled in areas shallower than the 40-m (131-ft) contour.
The 40-m (131-ft) contour is the depth within which more than 95
percent of southern sea otter dives occur (Tinker et al. 2006a). The
survey vessel would spend approximately 5.5 hours of the 23-day project
(survey portion) schedule in areas shallower than the 40-m (131-ft)
contour. However, because sound travels outward from the air guns,
areas within the 40-m (131-ft) contour would at times be ensonified to
levels of 160 decibels relative to one microPascal (dB re 1 [mu]Pa) or
greater even when the vessel is outside this contour. Portions of these
areas would be ensonified to levels of 160 dB re 1 [mu]Pa or greater
whenever the vessel was within 6.2 km (3.9 mi) of the 40-m (131-ft)
contour, totaling approximately 184 hours (115 and 69 hours for survey
box areas 2 and 4, respectively) over the duration of the survey. A
circular area surrounding the airguns with a radius of 1.0 km (0.63 mi)
would be ensonified to levels of 180 dB re 1 [mu]Pa or greater. This
area would be designated an ``exclusion zone'' (see Mitigation Measures
below).
b. Geographic Location of Activities
The 3D seismic survey track lines encompass an area of
approximately 740.5 km\2\ (285.9 mi\2\), including all survey box
overlapping areas (the actual survey footprint is approximately 631
km\2\ [244 mi\2\]). The offshore (vessel) survey would be conducted
between Cambria and the Santa Maria River mouth in both Federal and
State waters, in water depths ranging from 0 to over 400 m (1,300 ft).
The Point Buchon Marine Protected Area (MPA) lies within portions of
the survey area, and the Cambria and White Rock Marine Conservation
Areas (MCA) are located within areas of survey vessel turns. The
Monterey Bay National Marine Sanctuary (MBNMS), a federally protected
marine sanctuary that extends northward from Cambria to Marin County,
is located to the north of the project area.
Description of Habitat and Marine Mammals Affected by the Activity
The project would be conducted in rocky-bottom and sandy-bottom
marine habitat off the coast of central California in water depths
ranging from 0-400 m (1,300 ft). Sea otter habitat is typically defined
by the 40-m (131-ft) isobath (Laidre et al. 2001). Individually, survey
box areas 2 and 4 would ensonify 8.3 and 7.4 percent of the southern
sea otter range, respectively, to levels of 160 dB re 1 [mu]Pa or
greater. Because these survey box areas overlap, the total proportion
of the range affected is less than the sum of two survey box areas
viewed independently. In total, approximately 11.5 percent of the
habitat within which the mainland population of the southern sea otter
currently occurs would be ensonified to levels of 160 dB re 1 [mu]Pa or
greater over the duration of the survey. This habitat is located in the
southern half of the southern sea otter's range.
The southern sea otter is the only marine mammal under the
jurisdiction of the Service that would be affected by the proposed
project. Among the largest members of the family Mustelidae but the
smallest of marine mammals, southern sea otters exhibit limited sexual
dimorphism (males are larger than females) and can attain weights and
lengths up to 40 kg (88 lbs) and 140 cm (55 in), respectively. They
have a typical life span of 11-15 years (Riedman and Estes 1990).
Unlike most other marine mammals, sea otters have little subcutaneous
fat. They depend on their clean, dense, water-resistant fur for
insulation against the cold and maintain a high level of internal heat
production to compensate for their lack of blubber. Consequently, their
energetic
[[Page 59214]]
requirements are high, and they consume an amount of food equivalent to
approximately 23 to 33 percent of their body weight per day (Riedman
and Estes 1990). Contamination of the fur by oily substances can
destroy its insulating properties and lead to hypothermia and death.
The loss of the insulating properties of the fur exacerbates the
adverse effects of oil spills on southern sea otters and is one of the
reasons that increased tanker traffic and the potential for oil spills
was considered in the listing of the species.
Southern sea otters forage in both rocky and soft-sediment
communities in water depths generally 25 m (82 ft) or less, although
individuals occasionally move into deeper water. Individual animals
tend to specialize on a subset of the overall population diet. Dive
depth and dive pattern vary by sex (males tend to make deep dives more
frequently than females), geographic location, and diet specialization
(Tinker et al. 2006a, Tinker et al. 2007). Sea otters occasionally make
dives of up to 328 ft (100 m), but the vast majority of feeding dives
(more than 95 percent) occur in waters less than 131 ft (40 m) in depth
(Tinker et al. 2006a). Therefore, sea otter habitat is typically
defined by the 40-m (131-ft) isobath (Laidre et al. 2001).
The annual patterns that characterize the movements of southern sea
otters along the coast are complicated and vary between males and
females. Their home ranges tend to consist of several heavily used
areas with travel corridors between them. Animals often remain in an
area for a long period of time and then suddenly move long distances.
These movements can occur at any time of the year (Riedman and Estes
1990). Sub-adult males have the largest home ranges, followed by adult
males, sub-adult females, and adult females (Tinker et al. 2006a).
Compared to males, most females are more sedentary, although females
also occasionally travel long distances. Juvenile males move further
from natal groups than do juvenile females. Aggressive behavior
exhibited towards the juvenile males by breeding males may be partially
responsible for their more extensive travels (Ralls et al. 1996).
Jameson (1998) noted that adult male sea otters are territorial and
exclude juvenile and subordinate males from their territories. However,
females move freely across these territories. Generally, southern sea
otters occupy territories on a seasonal basis. Many males migrate to
the range peripheries during the winter and early spring, apparently to
take advantage of more abundant prey resources, but then return to the
range center during the period when most breeding occurs (June to
November) in search of estrous females (Jameson 1989; Tinker et al.
2006a; Tinker et al. 2006b). A peak period of pupping occurs from
January to March, and a secondary pupping season occurs in late summer
and early fall (Riedman et al. 1994). Parental care is provided solely
by the female.
Status and Distribution of Affected Species
Southern sea otters are listed as threatened under the Endangered
Species Act of 1973, as amended (ESA), and because of their threatened
status are automatically considered ``depleted'' under the MMPA. A
final revised recovery plan for the southern sea otter was published in
2003 (68 FR 16305). The State of California also recognizes the
southern sea otter as a fully protected mammal (Fish and Game Code
section 4700) and as a protected marine mammal (Fish and Game Code
section 4500).
All members of the southern sea otter population are descendants of
a small group that survived the fur trade near Big Sur, California.
Historically ranging from at least as far north as Oregon (Valentine et
al. 2008) to Punta Abreojos, Baja California, Mexico, in the south,
southern sea otters currently occur in only two areas of California.
The mainland population ranges from San Mateo County in the north to
Santa Barbara County in the south and numbers approximately 2,800
animals (the 3-year running average based on the spring 2012 census is
2,792) (http://www.werc.usgs.gov/Project.aspx?ProjectID=91). A small
translocated population occurs at San Nicolas Island, numbering
approximately 50 independent animals as of 2012 (USGS unpublished
data). Data from recent years suggest that southern sea otter
population numbers overall are stable or slightly declining.
Southern sea otter abundance varies considerably across the range,
with the highest densities occurring in the center part of the range
(Monterey peninsula to Estero Bay), where they have been present for
the longest. Densities tend to be most stable from year to year in
rocky, kelp-dominated areas that are primarily occupied by females,
dependent pups, and territorial males. In contrast, sandy and soft-
bottom habitats (in particular Monterey Bay, Estero Bay, and Pismo
Beach to Pt. Sal) tend to be occupied by males and sub-adult animals of
both sexes (but rarely by adult females and pups) and are more variable
in abundance from year to year. This variation is apparently driven in
part by the long-distance movements and seasonal redistribution of
males (Tinker et al. 2006b). The variability of counts at the south end
of the range is also related to the seasonal movements of males
migrating to the range peripheries during the winter and early spring
(Tinker et al. 2006a, Tinker et al. 2006b).
Standardized range-wide counts of southern sea otters were
initiated in 1982. Census and distribution data are available from the
U.S. Geological Survey Western Ecological Research Center at http://www.werc.usgs.gov/ProjectSubWebPage.aspx?SubWebPageID=4&ProjectID=91.
These data include various density estimates delineated by polygons
along the central California coast from shore to the 30-m (98-ft) depth
contour and between the 30-m (98-ft) and 60-m (197-ft) depth contours.
Based on these density estimates, Padre Associates calculated average
sea otter densities for survey box areas 2 and 4 and the associated 160
dB re 1 [mu]Pa exposure areas that comprise the project footprint: 1.07
and 1.7 sea otters/km\2\ (2.77 and 4.4 sea otters/mi\2\), respectively.
Potential Impacts of the Proposed Seismic Survey on Sea Otters
Disturbance Reactions
Little is known regarding the effects of sound on sea otters. Sea
otters have not been reported as being particularly sensitive to sound
disturbance, especially in comparison to other marine mammals. For
instance, Riedman (1983, 1984) observed the behavior of sea otters
along the California coast during single, 100-in\3\ air gun pulses and
pulses from a 4,089-in\3\ air gun array. The air gun array produced
low-frequency (5-500-Hertz [Hz]) sounds at 230 dB re 1 [mu]Pa at 1 m.
No disturbance reactions were evident when the air gun array was as
close as 0.9 km (0.5 mi), and the sea otters did not respond noticeably
to the single air gun. The proposed seismic survey air gun array has an
air discharge volume of approximately 3,300 in\3\, a dominant frequency
of 0-188 Hz, and a source output (downward) of 252 dB re 1 [mu]Pa at 1
m.
Underwater sounds are not likely to affect sea otters at the
surface, due to the pressure release effect. Thus, the susceptibility
of sea otters to disturbance from underwater sounds is probably
restricted to behaviors during which the head is submerged, such as
during foraging dives and underwater swimming and, intermittently,
during grooming bouts. Yeates et al. (2007) reported the following mean
percent activity categories for six adult male
[[Page 59215]]
California sea otters: Feeding (36.3), resting (40.2), swimming (8.5),
grooming (9.1), and other (7.3). In a study with a much larger sample
size, Tinker et al. (2008) reported that central California sea otters
spent approximately 40 percent of their time foraging. Because
underwater behaviors constitute less than half of the total activity
budget of southern sea otters along the central California coast, their
exposure to underwater sounds is limited. Nevertheless, the disruption
of underwater behaviors may result in the disruption of the entire
activity budget of an exposed individual and, potentially, in the
disturbance of associated individuals. In the case of the proposed
seismic survey, which consists of multiple parallel closely spaced
transect lines, with a time for one complete circuit of 14.94 hours
(survey box area 2) or 6.78 hours (survey box area 4), it is virtually
certain that any sea otter engaging in surface behaviors during one
pass of the vessel would be engaging in underwater behaviors during a
subsequent pass of the vessel. Therefore, all sea otters that remained
in the area would ultimately be exposed to underwater sound associated
with the seismic survey.
Observed sea otter responses to disturbance are highly variable,
probably reflecting the level of noise and activity to which they have
been exposed and become acclimated over time and the particular
location and social or behavioral state of that individual (G. Bentall,
Monterey Bay Aquarium Sea Otter Research and Conservation Program,
pers. comm.). Reactions to anthropogenic noise can be manifested as
visible startle responses, flight responses (flushing into water from
haulouts or ``splash-down'' alarm behavior in surface-resting rafts),
changes in moving direction and/or speed, changes in or cessation of
certain behaviors (such as grooming, socializing, or feeding), or
avoidance of areas where noise sources are located.
The biological significance of these behavioral disturbances is
difficult to predict, especially if the detected disturbances appear
minor. However, the consequences of behavioral modification would be
expected to be biologically significant if the change affected growth,
survival, or reproduction. Potentially significant behavioral
modifications include:
Disturbance of resting sea otters
Marked disruption of foraging behaviors
Separation of mothers from pups
Disruption of spatial and social patterns (sexual segregation
and male territoriality)
Currently, NMFS uses 160 dB re 1 [mu]Pa at received level for
impulse noises (such as air gun pulses) as the onset of behavioral
harassment (Level B harassment) for all marine mammals that are under
its jurisdiction, and 180 dB re 1 [mu]Pa at received level as the
threshold for potential injury or permanent physiological damage (Level
A harassment) for cetaceans (70 FR 1871, January 11, 2005). In the
absence of data on which to base thresholds specific to sea otters, we
utilize the 160 dB re 1 [mu]Pa and 180 dB re 1 [mu]Pa thresholds for
Level B and Level A harassment of sea otters. Based on the 160 dB re 1
[mu]Pa exposure area for survey box areas 2 and 4 and the average
densities of sea otters in these areas, we estimate that approximately
352 sea otters will be exposed to underwater sound levels of 160 dB re
1 [mu]Pa or greater (Table 2). Note that because survey box areas 2 and
4 overlap, the total number of sea otters expected to be exposed to
this level of sound is less than the sum of the numbers of sea otters
in the 160 dB re 1 [mu]Pa exposure areas for survey box areas 2 and 4.
In the overlapping area, sea otters will be subject to sound exposures
associated with both survey box areas. Because limited evidence
suggests that sea otters are less suceptible to acoustic disturbance
than other marine mammals, these thresholds may be overly conservative.
If, during implementation of the project, sea otters appeared to be
undisturbed by sound to the extent that the exclusion zone (see
Mitigation Measures below) could not be successfully kept clear of sea
otters, the applicant would have the option under the IHA to request
that the Service approve a reduction of the exclusion zone radius. We
would review the request and notify the applicant of our determination.
Table 2--Estimated Number of Sea Otters Exposed to Underwater Sound Levels of 160 dB re 1 [mu] Pa or Greater
----------------------------------------------------------------------------------------------------------------
Portion of 160 dB
exposure area (km\2\) Number of sea otters/ Number of sea otters in
Survey box affecting sea otter km\2\ 160 dB exposure area
population
----------------------------------------------------------------------------------------------------------------
2.................................... 245 1.07 261
4.................................... 155 1.70 263
2 and 4 merged....................... 288 1.22 352
----------------------------------------------------------------------------------------------------------------
Hearing Impairment and Other Physical Effects
Exposure to very strong sounds could affect southern sea otters
physically in a number of ways. These include temporary threshold shift
(TTS), which is short-term hearing impairment, and permanent threshold
shift (PTS), which is permanent hearing loss. Non-auditory physical
effects may also occur in southern sea otters exposed to strong
underwater pulsed sound. Non-auditory physiological effects or injuries
that may theoretically occur in mammals close to a strong sound source
include stress, neurological effects, and other types of organ or
tissue damage. However, there is no definitive evidence that any of
these effects occur in sea otters, even those in close proximity to
large arrays of air guns. It is unlikely that any effects of these
types would occur during the present project given the brief duration
of exposure of any given sea otter and the planned monitoring and
mitigation measures. The following subsections discuss in more detail
the possibilities of TTS, PTS, and non-auditory physical effects.
Temporary Threshold Shift (TTS)
TTS is the mildest form of hearing impairment that can occur during
exposure to a strong sound (Kryter 1985). While an animal is
experiencing TTS, the hearing threshold rises and a sound must be
stronger in order to be heard. It is a temporary phenomenon, and
(especially when mild) is not considered physical damage or ``injury''
(Southall et al. 2007). Rather, the onset of TTS is an indicator that,
if the animal is exposed to higher levels of that sound, physical
damage is ultimately a possibility.
The magnitude of TTS depends on the level and duration of noise
exposure and, to some degree, on frequency, among other considerations
(Kryter 1985; Richardson et al. 1995; Southall et
[[Page 59216]]
al. 2007). For sound exposures at or somewhat above the TTS threshold,
hearing sensitivity recovers rapidly after exposure to the noise ends.
In terrestrial mammals, TTS can last from minutes or hours to days.
Only limited data have been obtained on sound levels and durations
necessary to elicit mild TTS in marine mammals, and none of the
published data concern TTS elicited by exposure to multiple pulses of
sound during operational seismic surveys (Southall et al. 2007).
Permanent Threshold Shift (PTS)
When PTS occurs, there is physical damage to the sound receptors in
the ear. In severe cases, there can be total or partial deafness. In
other cases, the animal has an impaired ability to hear sounds in
specific frequency ranges (Kryter 1985). There is no specific evidence
that exposure to pulses from air guns can cause PTS in any marine
mammal, even with large arrays of air guns. However, given the
possibility that mammals close to an air gun array might incur at least
mild TTS in the absence of appropriate mitigation measures, there has
been further speculation about the possibility that some individuals in
very close proximity to air guns might incur PTS (e.g., Richardson et
al. 1995; Gedamke et al. 2008). Single or occasional occurrences of
mild TTS are not indicative of permanent auditory damage, but repeated
or (in some cases) single exposures to a level well above that causing
TTS might elicit PTS.
Vessel Collision Effects
Boat strikes are a relatively low but persistent source of sea
otter mortality. During the 2006-2010 period, 11 sea otters were
suspected to have been struck by boats (USGS and CDFG unpub. data).
However, vessel strikes involving sea otters appear primarily to
involve small, fast boats, and most collision reports have come from
small vessels (NMFS 2003; NMFS 2006). Because sea otters spend a
considerable portion of their time at the surface of the water, they
are typically visually aware of approaching boats and are able to move
away if the vessel is not traveling too quickly. The noise of
approaching boats provides an additional warning. Because the R/V
Marcus G. Langseth and associated scout boats would be traveling
relatively slowly (4.5 knots), it is unlikely that sea otters would
suffer injury or death from a vessel collision.
Potential Impacts on Habitat
The proposed seismic survey would not result in any known impacts
on the habitats used by southern sea otters or the food sources they
exploit. The main impact of the project would be temporarily elevated
noise levels. Although approximately 11.5 percent of the mainland
southern sea otter range would eventually be ensonified to sound levels
of 160 dB re 1 [mu]Pa or greater by the time the survey was completed,
only one circular area with a radius of approximately 6.2 km (3.9 mi)
would be ensonified to these levels or greater at any one time.
Preliminary biological surveys have been completed for the areas
where marine geophone lines are proposed to be placed to ensure they
are routed along corridors that minimize contact with rock substrates,
kelp canopy areas, and seagrass beds. In areas where such habitats are
unavoidable due to their contiguous distribution along the coastline,
the placement and recovery of the small geophone units in potentially
sensitive areas would be done by divers/remotely operated vehicles
(ROVs) deployed from small vessels in such a way as to minimize any
potential effects and to ensure that no sea otter habitat is
permanently altered. All deployment and recovery operations would be
conducted during daylight hours and monitored by an onboard Protected
Species Observer (PSO).
Potential Impacts on Subsistence Needs
The subsistence provision of the MMPA does not apply to southern
sea otters.
Mitigation Measures
Efforts were made during the initial project planning phase to
identify the minimum energy source level needed for data collection and
thereby to minimize the sound impacts to the marine environment, to
reduce the area of the survey to only the area necessary for critical
data collection, and to consider and plan around marine biological
resources/life functions (such as presence, breeding, feeding, and
migration) in the survey area.
PG&E and LDEO are proposing the following mitigation measures to
reduce the potential effects of the project on southern sea otters
resulting from air guns and vessel activities:
PG&E would conduct an aerial survey approximately 1 week
prior to the start of the seismic survey to obtain pre-survey
information on the numbers and distribution of southern sea otters in
the seismic survey area. Weekly aerial surveys would also be conducted
throughout the survey program. Survey routes would be adjusted as
feasible to avoid concentrations of sea otters,
Protected Species Observers (PSOs) (NMFS-certified and
Service-approved) would be stationed on the primary survey vessel and
on the support and scout vessels. PSOs would also be present on vessels
involved in the deployment and recovery of marine geophones,
PSOs would visually monitor sea otters within the
designated survey exclusion (180 dB re 1 [mu]Pa) and safety (160dB re 1
[mu]Pa) zones during all daylight hours,
If one or more sea otters were observed near the exclusion
zone and appeared to be about to enter it, avoidance measures would be
taken, including decreasing vessel speed or implementing a power down,
If one or more sea otters were observed within the
exclusion zone, the air gun arrays would be shut down within several
seconds. The PSO would then maintain a watch to determine when the sea
otter(s) appeared to be outside the exclusion zone such that air gun
operations could resume,
Power-up, ramp-up, and shut-down procedures would be
implemented during all air gun operations,
A mitigation air gun (a continuously operated, low-volume,
single air gun versus all eighteen) would be used during survey turns
outside of the 3D survey area as well as during power-down and standby
periods to deter marine wildlife from re-entering the exclusion zone,
During nighttime operations, whenever the vessel survey
tracks were located inshore of the 40-meter depth contour (where
physical encounters with sea otters are more likely), PSOs would
visually monitor the area forward of the survey vessel with the aid of
infra-red (night vision) goggles/binoculars and the forward-looking
infra-red (FLIR) system available onboard the R/V Marcus G. Langseth.
Mitigation measures, such as avoidance or power-downs/shut-downs, would
be implemented if a sea otter were detected in the path of the survey
vessel.
Findings
The Service proposes the following findings regarding this action:
Small Numbers Determination and Estimated Take by Incidental Harassment
For small take analysis, the statute and legislative history do not
expressly require a specific type of numerical analysis, leaving the
determination of ``small'' to the agency's discretion. Factors
considered in our small numbers determination include the following:
(1) The number of southern sea otters inhabiting the proposed
impact area is
[[Page 59217]]
small relative to the size of the southern sea otter population. The
number of southern sea otters that could potentially be taken by
harassment in association with the proposed activity is 352, less than
13 percent of the estimated population size of 2,792.
(2) The area where the activity would occur is small relative to
the range of the southern sea otter. The combined footprint of survey
box areas 2 and 4 is 631 km\2\ (244 mi\2\) and the portion of this
combined footprint within sea otter range is 4.7 km\2\ (1.8 mi\2\),
whereas the southern sea otter range encompasses approximately 1,346
km\2\ (519.7 mi\2\). Therefore, the survey footprint would affect less
than 0.4 percent of the total range of the southern sea otter, and
exposure to the 160 dB sound levels would occur in less than 12 percent
of the total range of the southern sea otter. Additionally, it should
be noted that only one circular area, with a radius of approximately
6.2 km (3.9 mi), would be ensonified to these levels or greater at any
one time.
(3) Monitoring requirements and mitigation measures are expected to
limit the number of incidental takes. Level A harassment (harassment
that has the potential to injure southern sea otters) is not
authorized. PSOs would ensure that sea otters are not exposed to sounds
or activities that may result in Level A harassment. PSOs would be
present during all daylight survey activities and would have the
authority to order a power-down or shut-down of the seismic air guns,
and/or redirect survey activities to avoid observed sea otters if sea
otters appeared to enter or approach the 180 dB re 1 [mu]Pa exclusion
zone. If a sea otter were observed within or approaching the 180 dB re
1 [mu]Pa exposure area of 1,010 m (0.63 mi), avoidance measures would
be taken, such as decreasing the speed of the vessel and/or
implementing a power-down or shut-down of the air guns. Nighttime
monitoring would be conducted with the aid of night-vision binoculars
and a FLIR system when the R/V Marcus G. Langseth was inshore of the
40-m (131-ft) depth contour. All nearshore vessel operations associated
with marine geophone placements would be monitored by PSOs. Power-up
and ramp-up procedures would prevent Level A harassment and limit the
number of incidental takes by Level B harassment by affording time for
sea otters to leave the area. Monitoring and mitigation measures are
thus expected to prevent any Level A harassment and to minimize Level B
harassment.
It should be noted that if sea otters appeared to be undisturbed by
sound to the extent that the exclusion zone could not be successfully
kept clear of sea otters, the applicant would have the option to
request that the Service approve a reduction of the exclusion zone
radius. We would review the request and notify the applicant of our
determination. Our approval would not constitute authorization of Level
A harassment. Rather, our approval would be based on a determination,
following review of information on sea otter behavior obtained through
required monitoring during the survey, that a smaller exclusion zone
would avoid Level A harassment.
Negligible Impact
The Service finds that any incidental ``take by harassment'' that
may result from this proposed seismic survey 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, and would, therefore, have no more than a negligible impact
on the stock. In making this finding, we considered the best available
scientific information, including (1) The biological and behavioral
characteristics of the species, (2) the most recent information on
distribution and abundance of sea otters within the area of the
proposed activity, (3) the potential sources of short-term disturbance
during the proposed activity, and (4) the potential response of
southern sea otters to this short-term disturbance.
Limited evidence (Riedman 1983, 1984) suggests that sea otters are
not particularly sensitive to or adversely affected by sound. Responses
of sea otters to disturbance would most likely be diving and/or
swimming away from the sound source, which may entail the temporary,
but not sustained, interruption of foraging, breeding, resting, or
other natural behaviors. Thus, although 352 sea otters (approximately
13 percent of the mainland population) are estimated to be potentially
taken (i.e., potentially disturbed) by Level B harassment by means of
exposure to sound levels of 160dB re 1 [mu]Pa or greater over the
duration of the project, we do not expect that this type of harassment
would result in adverse effects on the species through effects on
annual rates of recruitment or survival. In order to verify this
conclusion, we have recommended that an ancillary scientific study be
conducted during the survey and afterwards to detect effects on
individual sea otters and any potential changes in annual rates of
recruitment and survival among sea otters exposed to sound. PG&E and
LDEO have agreed to arrange, with input from the Service, for this
study and subsequent analysis (see ``Marine Mammal Monitoring'' below).
The preliminary results of this study will be included in our analysis
should the applicant request incidental harassment authorization for
survey box area 1 in 2013.
The mitigation measures outlined above are intended to minimize the
number of sea otters that may be disturbed by the proposed activity.
Any impacts on individuals are expected to be limited to Level B
harassment and to be of short-term duration. No take by injury or death
is anticipated or authorized. Should the Service determine, based on
the monitoring and reporting to be conducted throughout the survey
activities, that the effects are greater than anticipated, the
authorization may be modified, suspended, or revoked.
Our finding of negligible impact applies to incidental take
associated with the proposed activity as mitigated through this
authorization process. This authorization establishes monitoring and
reporting requirements to evaluate the impacts of the authorized
activities, as well as mitigation measures designed to minimize
interactions with, and impacts to, southern sea otters.
Impact on Subsistence
The subsistence provision of the MMPA does not apply to southern
sea otters.
Marine Mammal Monitoring
The applicant would be required to conduct monitoring of southern
sea otters during the seismic surveys in order to implement the
mitigation measures that require real-time monitoring and to satisfy
monitoring required under the MMPA. Project personnel would be required
to record information regarding location and behavior of all sea otters
observed during operations. When conditions permitted, information
regarding age (pup, independent) and tag color and position (for
flipper-tagged animals) would also be required to be recorded.
Due to the lack of data on the effects of air guns on sea otters,
in addition to project-related mitigation monitoring, the Service has
recommended that PG&E and LDEO use the survey as an opportunity to
investigate the potential effects of air guns on sea otters. PG&E and
LDEO have agreed to address this request by arranging, with input from
the Service, for the design and implementation of an ancillary
scientific study during and after the survey and subsequent analysis.
The study would be conducted by
[[Page 59218]]
researchers with the appropriate scientific expertise and permits
(USGS, Biological Resources Division, in cooperation with the
California Department of Fish and Game and other research partners).
The Sea Otter Monitoring Program is described in Appendix E to the
revised IHA application. To supplement data obtained by researchers
from bottom-mounted passive acoustic recorders placed in and near kelp
beds used by resident sea otters, PG&E and LDEO would provide
researchers with GPS-referenced time data for the air gun shots from
the seismic survey vessel. These data would be used to validate the
acoustic modeling underlying the 160 dB re 1 [mu]Pa safety zone and 180
dB re 1 [mu]Pa exclusion zone radii, to measure the propagation of
sound through sea otter habitat, and to estimate received sound levels
that may be useful in determining sea otter behavioral response
thresholds as a function of sound exposure.
Monitoring and Reporting
The applicant would be required to implement the following
monitoring and reporting program to increase knowledge regarding the
species and to assess the level of take caused by the proposed action:
a. Pre-Activity Monitoring
Approximately 1 week prior to the start of seismic survey
operations, an aerial survey would be flown to establish a baseline for
numbers and distribution of southern sea otters in the project area;
b. Activity Monitoring
Vessel-based monitoring for marine wildlife, including southern sea
otters, would be done by trained PSOs throughout the period of survey
activities. PSO duties would include watching for and identifying
marine mammals; recording their numbers, distances, and any reactions
to the survey operations; and documenting potential ``take by
harassment'' as defined by the Service and NMFS.
A sufficient number of PSOs would be required onboard the survey
and support vessels to meet the following criteria:
100-percent monitoring during all periods of survey
operations (visual everywhere during daylight and inshore of the 40-m
contour at night); and
A maximum of four consecutive hours on watch per PSO.
PSO teams would consist of Service- and NMFS-approved PSOs and
experienced field biologists. An experienced crew leader would
supervise the PSO team onboard the survey vessels. Crew leaders and
biologists serving as PSOs would be individuals with experience as PSOs
during high-energy survey projects (HESS), and/or shallow hazards
surveys in California.
PSOs would be required to have previous marine mammal observation
experience, and field crew leaders would be highly experienced with
previous vessel-based marine mammal monitoring and mitigation projects.
Resumes for those individuals would be provided to the Service and NMFS
for review and acceptance of their qualifications. PSOs would be
familiar with the region and the marine mammals of the area and would
complete an in-house observer training course designed to familiarize
individuals with monitoring and data collection procedures.
The PSOs would watch for marine mammals from the best available
vantage point on the survey vessels, typically the PSO tower on the R/V
Marcus G. Langseth, or from dedicated monitoring vessels. The PSOs
would scan systematically with the unaided eye and with binoculars.
Personnel on the bridge of the survey and monitoring vessels would
assist the PSOs in watching for marine mammals.
Information recorded by PSOs would include:
Species, group size, age/size/gender (if determinable),
behavior when first sighted and after initial sighting, heading (if
determinable), bearing and distance from observer, apparent reaction to
activities (e.g., none, avoidance, approach, paralleling, etc.),
closest point of approach, and pace;
Time, location (GPS coordinates), sea state, visibility,
sun glare, and speed and activity of the vessel, and
Positions of other vessel(s) in the vicinity of the
observer location.
The ship's position, speed of the vessel, water depth, sea state,
visibility, and sun glare would also be recorded at the start and end
of each observation watch, every 30 minutes during a watch, and
whenever there were substantial changes in any of those variables.
If a southern sea otter were seen within the exclusion zone, the
geophysical crew would be notified immediately so that the mitigation
measures called for in the applicable authorization(s) could be
implemented. The air gun arrays would be shut down within several
seconds. The PSO would then maintain a watch to determine when the sea
otter(s) appeared to be outside the exclusion zone such that air gun
operations could resume.
Aerial surveys would be conducted weekly during seismic survey
operations to assist in the identification and avoidance of southern
sea otters within the project area;
c. Post-Activity Monitoring
Approximately 1 week prior to the completion of the offshore
seismic survey operations, a final aerial survey would be conducted to
document the number and distribution of southern sea otters in the
project area. These data would be used in comparison with original
survey data collected prior to the seismic operations.
No post-activity monitoring is proposed.
d. Reporting
Throughout the survey program, PSOs would prepare a report each
week summarizing the recent results of the monitoring program. The
reports would summarize the numbers of sea otters sighted. These
reports would be provided to the Service, PG&E, LDEO, and NSF.
The results of the vessel-based monitoring, including estimates of
potential ``take by harassment,'' would be compiled in a report and
submitted to the Service within 90 days of survey conclusion; the
report would also be posted on the NSF Web site at: http://www.nsf.gov/geo/oce/envcomp/index.jsp. Reporting would address any requirements
established by the Service and NMFS.
Along with any other State or Federal requirements, the 90-day
report would minimally include:
Summaries of monitoring effort: Total hours, total
distances, and distribution of marine mammals through the study period
accounting for sea state and other factors affecting visibility and
detectability of marine mammals;
Analyses of the effects of various factors influencing the
detectability of marine mammals, including sea state, number of
observers, and fog/glare;
Species composition and occurrence, and distribution of
marine mammal sightings, including date, water depth, numbers, age/
size/gender, and group sizes, and analyses of the effects of survey
operations;
Sighting rates of marine mammals during periods with and
without air gun activities (and other variables that could affect
detectability);
Initial sighting distances versus air gun activity state
(firing, powered down, or shut-down);
Closest point of approach versus air gun activity state;
[[Page 59219]]
Observed behaviors and types of movements versus air gun
activity state;
Numbers of sightings/individuals seen versus air gun
activity state;
Distribution around the survey vessel versus air gun
activity state; and
Estimates of ``take by harassment''.
Endangered Species Act
The southern sea otter is currently listed as threatened under the
Endangered Species Act of 1973, as amended (ESA). Because the proposed
activities may affect the southern sea otter, pursuant to section
7(a)(2) of the ESA, the Service must ensure that its issuance of the
IHA will not jeopardize the species. In addition, the NSF must ensure
that its provision of the R/V Marcus G. Langseth will likewise not
jeopardize the southern sea otter. To address the obligations of both
the Service and NSF pursuant to section 7(a)(2) of the ESA, the Service
has initiated internal formal consultation on issuance of an IHA, and
the NSF has initiated formal consultation with the Service for its
action of providing the R/V Marcus G. Langseth for the survey. These
consultations will be addressed in a single biological opinion. The
biological opinion will consider the effects of the project on the
southern sea otter, including our issuance of an IHA. The biological
opinion will be issued prior to the decision on the IHA.
National Environmental Policy Act (NEPA)
The seismic survey is described in the Draft EA prepared by the
applicant under the supervision of the NSF, the lead Federal agency. If
we find it to be adequate and appropriate, we will adopt the Draft EA
as the Service's Environmental Assessment (EA) of whether issuance of
the IHA would have a significant effect on the human environment. Our
analysis will be completed prior to issuance or denial of the IHA and
will be available at http://www.fws.gov/ventura/speciesinfo/. To obtain
a copy of the Draft EA, contact the individual identified in the FOR
FURTHER INFORMATION CONTACT section.
Government-to-Government Relations With Native American Tribal
Governments
In accordance with the President's memorandum of April 29, 1994,
``Government-to-Government Relations with Native American Tribal
Governments'' (59 FR 22951), Executive Order 13175, Secretarial Order
3225, and the Department of the Interior's manual at 512 DM 2, we
readily acknowledge our responsibility to communicate meaningfully with
Federally recognized Tribes on a Government-to-Government basis. We
have evaluated possible effects on federally recognized Indian Tribes
and have determined that there are no effects.
Proposed Authorization
The Service proposes to issue an IHA for southern sea otters
harassed incidentally by the applicant in the course of conducting
seismic surveys beginning October 15, 2012, and ending December 31,
2012. Mobilization could begin as early as October 15, but sound source
verification procedures and active air gun surveys would start no
earlier than November 1. Authorization for incidental take beyond this
time period would require a new request. The final IHA, if issued, will
incorporate the mitigation, monitoring, and reporting requirements
discussed in this proposal. The applicant would be responsible for
following those requirements. If the level of activity exceeded that
described by the applicant, or the level or nature of take exceeded
those projected here, the Service would reevaluate its findings.
Conversely, if sea otters appeared to be undisturbed by sound to the
extent that the exclusion zone could not be successfully kept clear of
sea otters, the applicant would have the option to request that the
Service approve a reduction of the exclusion zone radius. We would
review the request and notify the applicant of our determination. The
Secretary would have the ability to modify, suspend, or revoke this
authorization if the findings were not accurate or the conditions
described in this notice were not being met. Should the applicant
request incidental harassment authorization for survey box area 1 in
2013, the Service will re-analyze the small numbers and negligible
impact determinations, which would include an evaluation of the
information gained through the monitoring and reporting requirements
proposed in this IHA, and make a new finding at that time.
Request for Public Comments
The Service requests interested parties to submit comments and
information concerning this proposed IHA. Consistent with section
101(a)(5)(D)(iii) of the MMPA, we are opening the comment period on
this proposed authorization for 30 days (see DATES).
Before including your address, phone number, email address, or
other personal identifying information in your comment, you should be
aware that your entire comment--including your personal identifying
information--may be made publicly available at any time. While you can
ask us in your comment to withhold your personal identifying
information from public review, we cannot guarantee that we will be
able to do so.
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Alexandra Pitts,
Deputy Regional Director, Pacific Southwest Region.
[FR Doc. 2012-23749 Filed 9-24-12; 11:15 am]
BILLING CODE 4310-55-P