Takes of Marine Mammals Incidental to Specified Activities; Marine Geophysical Survey off the Central Coast of California, November to December, 2012, 58255-58289 [2012-22999]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 77, Number 182 (Wednesday, September 19, 2012)]
[Notices]
[Pages 58255-58289]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-22999]



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Vol. 77

Wednesday,

No. 182

September 19, 2012

Part III





Department of Commerce





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 Takes of Marine Mammals Incidental to Specified Activities; Marine 
Geophysical Survey off the Central Coast of California, November to 
December, 2012; Notice

Federal Register / Vol. 77 , No. 182 / Wednesday, September 19, 2012 
/ Notices

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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XC072


Takes of Marine Mammals Incidental to Specified Activities; 
Marine Geophysical Survey off the Central Coast of California, November 
to December, 2012

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

ACTION: Notice; proposed Incidental Harassment Authorization; request 
for comments.

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SUMMARY: NMFS has received an application from the Lamont-Doherty Earth 
Observatory of Columbia University (L-DEO), in cooperation with the 
Pacific Gas and Electric Company (PG&E), for an Incidental Harassment 
Authorization (IHA) to take marine mammals, by harassment, incidental 
to conducting a marine geophysical (seismic) survey off the central 
coast of California, November to December, 2012. Pursuant to the Marine 
Mammal Protection Act (MMPA), NMFS is requesting comments on its 
proposal to issue an IHA to L-DEO and PG&E to incidentally harass, by 
Level B harassment only, 25 species of marine mammals during the 
specified activity.

DATES: Comments and information must be received no later than October 
15, 2012.

ADDRESSES: Comments on the application should be addressed to P. 
Michael Payne, Chief, Permits and Conservation Division, Office of 
Protected Resources, National Marine Fisheries Service, 1315 East-West 
Highway, Silver Spring, MD 20910. The mailbox address for providing 
email comments is ITP.Goldstein@noaa.gov. NMFS is not responsible for 
email comments sent to addresses other than the one provided here. 
Comments sent via email, including all attachments, must not exceed a 
10-megabyte file size.
    All comments received are a part of the public record and will 
generally be posted to https://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications without change. All Personal Identifying 
Information (for example, name, address, etc.) voluntarily submitted by 
the commenter may be publicly accessible. Do not submit confidential 
business information or otherwise sensitive or protected information.
    A copy of the application containing a list of the references used 
in this document may be obtained by writing to the above address, 
telephoning the contact listed here (see FOR FURTHER INFORMATION 
CONTACT) or visiting the internet at: https://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications.
    The National Science Foundation (NSF), which owns the R/V Marcus G. 
Langseth, has prepared a draft ``Environmental Assessment Pursuant to 
the National Environmental Policy Act, 42 U.S.C. 4321 et seq. Marine 
Seismic Survey in the Pacific Ocean off Central California, 2012'' 
(EA). NSF's EA incorporates a draft ``Environmental Assessment of 
Marine Geophysical Surveys by the R/V Marcus G. Langseth for the 
Central California Seismic Imaging Project,'' prepared by Padre 
Associates, Inc., on behalf of NSF, PG&E, and L-DEO, which is also 
available at the same internet address. Documents cited in this notice 
may be viewed, by appointment, during regular business hours, at the 
aforementioned address.

FOR FURTHER INFORMATION CONTACT: Howard Goldstein or Jolie Harrison, 
Office of Protected Resources, NMFS, 301-427-8401.

SUPPLEMENTARY INFORMATION:

Background

    Section 101(a)(5)(D) of the MMPA, as amended (16 U.S.C. 
1371(a)(5)(D)), directs the Secretary of Commerce (Secretary) to 
authorize, upon request, the incidental, but not intentional, taking of 
small numbers of marine mammals of a species or population stock, by 
United States citizens who engage in a specified activity (other than 
commercial fishing) within a specified geographical region if certain 
findings are made and, if the taking is limited to harassment, a notice 
of a proposed authorization is provided to the public for review.
    Authorization for the incidental taking of small numbers of marine 
mammals shall be granted if NMFS finds that the taking will have a 
negligible impact on the species or stock(s), and will not have an 
unmitigable adverse impact on the availability of the species or 
stock(s) for subsistence uses (where relevant). The authorization must 
set forth the permissible methods of taking, other means of effecting 
the least practicable adverse impact on the species or stock and its 
habitat, and requirements pertaining to the mitigation, monitoring and 
reporting of such takings. 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.''
    Section 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. 
Section 101(a)(5)(D) of the MMPA establishes a 45-day time limit for 
NMFS's 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 public comment period, NMFS must either issue or deny the 
authorization.
    Except with respect to certain activities not pertinent here, the 
MMPA defines ``harassment'' as: Any act of pursuit, torment, or 
annoyance which (i) has the potential to injure a marine mammal or 
marine mammal stock in the wild [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 [Level B harassment].

Summary of Request

    On May 17, 2012, NMFS received an application from the L-DEO and 
PG&E requesting that NMFS issue an IHA for the take, by Level B 
harassment only, of small numbers of marine mammals incidental to 
conducting a marine seismic survey within the U.S. Exclusive Economic 
Zone off the central coast of California during November to December, 
2012. NMFS received a revised application on August 31, 2012. The 
updated IHA application reflects revisions to the proposed project that 
have resulted from discussions between NMFS and the applicant during 
the MMPA consultation process, as well as other Federal and State 
regulatory requirements and include the elimination of portions of the 
originally planned survey area (specifically Survey Box 3) and the 
splitting of the proposed project into two years, and the shortening of 
the 2012 work window to November and December. Additionally, PG&E has 
agreed to operationally and financially support the design and 
implementation of a comprehensive monitoring, stranding response, and 
adaptive management plan that will support real-time decision making to 
reduce impacts to the Morro Bay stock of harbor porpoises (Phocoena 
phocoena). L-DEO and PG&E plan to

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use one source vessel, the R/V Marcus G. Langseth (Langseth) and a 
seismic airgun array to collect seismic data as part of the ``Offshore 
Central Coastal California Seismic Imaging Project'' located in the 
central area of San Luis Obispo County, California.
    PG&E proposes to conduct a high energy seismic survey in the 
vicinity of the Diablo Canyon Power Plant and known offshore fault 
zones near the power plant. The observations will be interpreted in the 
context of global synthesis of observations bearing on earthquake 
rupture geometries, earthquake displacements, fault interactions, and 
fault evolution. Estimating the limits of future earthquake ruptures is 
becoming increasingly important as seismic hazard maps are based on 
geologists' maps of active faults and, locally, the Hosgri Fault 
strikes adjacent to one of California's major nuclear power plants. In 
addition to the proposed operations of the seismic airgun array and 
hydrophone streamer, L-DEO and PG&E intend to operate a multibeam 
echosounder and a sub-bottom profiler continuously throughout the 
survey.
    Acoustic stimuli (i.e., increased underwater sound) generated 
during the operation of the seismic airgun array may have the potential 
to cause a behavioral disturbance for marine mammals in the survey 
area. This is the principal means of marine mammal taking associated 
with these activities and L-DEO and PG&E have requested an 
authorization to take 25 species of marine mammals by Level B 
harassment. Take is not expected to result from the use of the 
multibeam echosounder or sub-bottom profiler, for reasons discussed in 
this notice; nor is take expected to result from collision with the 
source vessel because it is a single vessel moving at a relatively slow 
speed (4.6 knots [kts]; 8.5 kilometers per hour [km/hr]; 5.3 miles per 
hour [mph]) during seismic acquisition within the survey, for a 
relatively short period of time (approximately 50 days). It is likely 
that any marine mammal would be able to avoid the vessel.

Description of the Proposed Specified Activity

Project Purpose

    PG&E proposes to conduct a high energy seismic survey in the 
vicinity of the Diablo Canyon Power Plant and known offshore fault 
zones near the power plant (see Figure 1 of the IHA application). The 
project, as proposed by L-DEO and PG&E, consists of deploying seismic 
or sound sources and receivers at onshore and offshore locations to 
generate data that can be used to improve imaging of major geologic 
structures and fault zones in the vicinity of the Diablo Canyon Power 
Plant. The details of the proposed seismic studies are outlined in a 
Science Plan submitted to the National Science Foundation (NSF) by L-
DEO, University of Nevada, and Scripps Institution of Oceanography. 
NSF, as owner of the Langseth will serve as the lead Federal agency and 
will ensure the approval of the proposed Science Plan is in compliance 
with the National Environmental Policy Act (NEPA) of 1969.
    These seismic studies would provide additional insights of any 
relationships or connection between the known faults as well as enhance 
knowledge of offshore faults in proximity to the central coast of 
California and the Diablo Canyon Power Plant. The proposed deep 
penetrating (10 to 15 kilometers [km] or 6 to 9 miles [mi]), high 
energy seismic survey (energy greater than 2 kilo Joule) would 
complement a previously completed shallow (less than 1 km [0.6 mi]), 
low energy (less than 2 kilo Joule) three-dimensional (3D) seismic 
reflection survey.
    The objectives of the proposed high energy 3D seismic survey are 
to:
     Record high resolution two-dimensional (2D) and 3D seismic 
reflection profiles of major geologic structures and fault zones in the 
vicinity of the central coast of California and Diablo Canyon Power 
Plant.
     Obtain high-resolution deep-imaging (greater than 1 km 
[0.6 mi]) of the Hosgri and Shoreline fault zones in the vicinity of 
the Diablo Canyon Power Plant to constrain fault geometry and slip rate 
(scheduled for the seismic survey activities in 2013).
     Obtain high-resolution, deep-imaging of the intersection 
of the Hosgri and Shoreline fault zones near Point Buchon.
     Obtain high-resolution, deep-imaging of the geometry and 
slip rate of the Los Osos fault, as well as the intersection of the 
Hosgri and Los Osos fault zones in Estero Bay.
     Augment the current regional seismic database for 
subsequent use and analysis through the provision of all data to the 
broader scientific and safety community.
    The studies require the collection of data over a long period of 
time. However, the project timeframe is limited to fall and winter 
months to minimize environmental impacts to the greatest extent 
feasible. L-DEO and PG&E are proposing to conduct the studies 24 hours 
a day for 7 days a week. This schedule is designed to reduce overall 
air emissions, length of time for operation in the water thereby 
reducing impacts to marine wildlife, commercial fishing, and other area 
users. PG&E will work with environmental agencies to appropriately 
address the balancing of public health and safety and environmental 
concerns during the conduct of these studies.

Survey Details

    The proposed survey involves both marine (offshore) and land 
(onshore) activities. The offshore components consist of operating a 
seismic survey vessel and support/monitoring vessels within the areas 
shown in Figure 1 of the IHA application and transiting between the 
four different survey box areas extending between the mouth of the 
Santa Maria River and Estero Bay. The seismic survey vessel would tow a 
series of sound-generating airguns and sound-recording hydrophones 
along pre-determined shore parallel and shore-perpendicular transects 
to conduct deep (10 to 15 km [6 to 9 mi]) seismic reflection profiling 
of major geologic structures and fault zones in the vicinity of the 
Diablo Canyon Power Plant.
    The offshore part of the survey activities include the placement of 
a limited number of seafloor geophones (e.g., Fairfield Z700 nodal 
units) into nearshore waters.
    The planned seismic survey (e.g., equipment testing, startup, line 
changes, repeat coverage of any areas, and equipment recovery) will 
consist of approximately 3,565.8 km (1,925.4 nmi) (1,417.6 km [765.4 
nmi] for Survey Box 4 and 2,148.2 km [1,159.9 nmi] for Survey Box 2) of 
transect lines (including turns) in the survey area off the central 
coast of California (see Figure 2 of the IHA application). In addition 
to the operations of the airgun array, a Kongsberg EM 122 multibeam 
echosounder and Knudsen Chirp 3260 sub-bottom profiler will also be 
operated from the Langseth continuously throughout the cruise. There 
will be additional seismic operations associated with equipment 
testing, ramp-up, and possible line changes or repeat coverage of any 
areas where initial data quality is sub-standard. In L-DEO and PG&E's 
estimated take calculations, 25% has been added for those additional 
operations. Detailed descriptions of the proposed actions for each 
component are provided below in this document.

Vessel Movements

    The tracklines for the 3D seismic survey will encompass an area of

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approximately 740.52 km\2\ (215.9 square nautical miles [nmi\2\]). The 
2012 project area is divided into two ``primary target areas'' (Survey 
Boxes 2 and 4) are described below and shown in Figure 2 of the IHA 
application. The offshore (vessel) survey would be conducted in both 
Federal and State waters and water depths within the proposed survey 
areas ranging from 0 to over 400 m (1,300 ft). The State Three-Mile 
Limit is identified in Figure 1 of the IHA application. The Point 
Buchon Marine Protected Area lies within portions of the survey area. 
In addition, the Monterey Bay National Marine Sanctuary, a Federally-
protected marine sanctuary that extends northward from Cambria to 
Marine County, is located to the north and outside of the proposed 
project area.
    Survey Box 2 (Survey area from Estero Bay to offshore Santa Maria 
River Mouth):
     Area: 406.04 km\2\ (118.4 nmi\2\);
     Total survey line length is 2,148.2 km (1,159.9 nmi); and
     Strike line surveys along the Hosgri fault zone and 
Shoreline, Hosgri, and Los Osos fault intersections.
    Survey Box 4 (Estero Bay):
     Area: 334.48 km\2\ (97.5 nmi\2\);
     Total survey line length is 1,417.6 km (765.4 nmi);
     Dip line survey across the Hosgri and Los Osos fault zones 
in Estero Bay.
    Figure 2 of the IHA application depicts the proposed survey transit 
lines. These lines depict the survey lines as well as the turning legs. 
The full seismic array is firing during the straight portions of the 
track lines as well as the initial portions of the run-out (offshore) 
sections and later portions of the run-in (inshore) sections. During 
turns and most of the initial portion of the run-ins, there will only 
be one airgun firing (i.e., mitigation airgun). Assuming a daily survey 
rate of approximately 8.3 km/hour (km/hr) (4.5 knots [kts] for 24/7 
operations), the Survey Box 2 is expected to take approximately 14 days 
and approximately 9.25 days for Survey Box 4. When considering 
mobilization, demobilization, refueling, equipment maintenance, 
weather, marine mammal activity, and other contingencies, the proposed 
survey is expected to be completed in 49.25 days.

Mobilization and Demobilization

    The offshore equipment and vessels for the proposed 3D marine 
seismic survey are highly specialized and typically no seismic vessels 
are located in California. The proposed seismic survey vessel (R/V 
Marcus G. Langseth) is currently operating on the U.S. west coast and 
is available to conduct the proposed seismic survey work.
    The Langseth would transit south prior to the start of survey 
operations (approximately October 15 through December 31, 2012, with 
active airgun survey operations starting approximately November 1, 
2012). Once the vessel has arrived in the project area, the survey 
crew, any required equipment, and support provisions would be 
transferred to the vessel. Larger equipment, if required, would need to 
be loaded onboard the vessel at either Port of San Francisco/Oakland or 
Port Hueneme. The proposed survey vessel is supported by two chase/
scout boats, each with three Protected Species Observers (PSOs) and a 
third support boat that will provide logistical support to the Langseth 
or chase boats. This support vessel will also serve as a relief vessel 
for either of the two chase boats as required or equivalent. Any 
additional scout/monitoring vessels required for the proposed project 
will be drawn from local vessel operators. Upon completion of the 
offshore survey operations, the survey crew would be transferred to 
shore and the survey vessel would transit out to the proposed project 
area.
    Nearshore operations would be conducted using locally available 
vessels such as the M/V Michael Uhl (Michael Uhl) or equivalent vessel. 
Equipment, including the geophones and cables, would be loaded aboard 
the Michael Uhl in Morro Bay Harbor and transferred to the offshore 
deployment locations. Following deployment and recovery of the 
geophones and cables, they would be transferred back to Morro Bay 
Harbor for transport offsite.
    During onshore operations, receiver line equipment would be 
deployed by foot-based crews supported by four-wheel drive vehicles or 
small vessel. Once the proposed project has been completed, the 
equipment would demobilize from the area by truck.

Offshore Survey Operations

    The proposed offshore seismic survey would be conducted with 
vessels specifically designed and built to conduct such surveys. PG&E 
has selected the Langseth, which is operated by L-DEO. The following 
outlines the general specifications for the Langseth and the support 
vessels needed to complete the proposed offshore seismic survey.
    In water depths from 30 to 305 m (100 to greater than 1,000 ft), 
the Langseth will tow four hydrophone streamers with a length of 
approximately 6 km (3.2 nmi). The intended tow depth of the streamers 
is approximately 9 m (29.5 ft). Flotation is provided on each streamer 
as well as streamer recovery devices. The streamer recovery devices are 
activated when the streamer sinks to a pre-determined depth (e.g., 50 m 
[164 ft]) to aid in recovery.
     Primary vessel--the Langseth is 71.5 m (235 ft) in length, 
and is outfitted to deploy/retrieve hydrophone streamers and airgun 
array, air compressors for the airgun array, and survey recording 
facilities.
     Two Chase/Scout boats--22.9 to 41.2 m (75 to 135 ft) in 
length and will be around the Langseth to observe potential 
obstructions, conduct additional marine mammal monitoring and support 
deployment of seismic equipment.
     Third support vessel-will be approximately 18.3 to 25.9 m 
(60 to 85 ft) in length and would act as a support boat for the 
Langseth and the two other chase/scout and would provide relief to 
either chase/scout boat as required.
     A nearshore work vessel (e.g., Michael Uhl) approximately 
50 m (150 ft) in length would be used to deploy and retrieve seafloor 
geophones in the shallow water (0 to 20 m) zone.
     Monitoring aircraft--Partenavia P68-OBS ``Observer,'' a 
high-wing, twin-engine plane or equivalent aircraft is 9.5 m (31 ft) in 
length and has a wingspan of 12 m (39 ft) with a carrying capacity of 
six persons. The aircraft has two ``bubble'' observation windows, a 
glass nose for clear observation, and will be equipped with 
communication and safety equipment sufficient to support the proposed 
operations. The aircraft would be used to perform aerial surveys of 
marine mammals.

Vessel Specifications

    The Langseth, a seismic research vessel owned by the NSF, will tow 
the 36 airgun array, as well as the hydrophone streamer, along 
predetermined lines (see Figure 2 of the IHA application). When the 
Langseth is towing the airgun array and the hydrophone streamer, the 
turning rate of the vessel is limited to three degrees per minute (2.5 
km [1.5 mi]). Thus, the maneuverability of the vessel is limited during 
operations with the streamer. The vessel would ``fly'' the appropriate 
U.S. Coast Guard-approved day shapes (mast head signals used to 
communicate with other vessels) and display the appropriate lighting to 
designate the vessel has limited maneuverability.
    The vessel has a length of 71.5 m (235 ft); a beam of 17.0 m (56 
ft); a maximum draft of 5.9 m (19 ft); and a gross tonnage of 3,834. 
The Langseth was designed as a seismic research vessel with a 
propulsion system designed to be as quiet as possible to avoid 
interference with the seismic signals emanating from

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the airgun array. The ship is powered by two 3,550 horsepower (hp) 
Bergen BRG-6 diesel engines which drive two propellers directly. Each 
propeller has four blades and the shaft typically rotates at 750 
revolutions per minute. The vessel also has an 800 hp bowthruster, 
which is not used during seismic acquisition. The Langseth's operation 
speed during seismic acquisition is typically 7.4 to 9.3 km per hour 
(hr) (km/hr) (4 to 5 knots [kts]). When not towing seismic survey gear, 
the Langseth typically cruises at 18.5 km/hr (10 kts). The Langseth has 
a range of 25,000 km (13,499 nmi) (the distance the vessel can travel 
without refueling).
    The vessel also has an observation tower from which Protected 
Species Visual Observers (PSVO) will watch for marine mammals before 
and during the proposed airgun operations. When stationed on the 
observation platform, the PSVO's eye level will be approximately 21.5 m 
(71 ft) above sea level providing the PSVO an unobstructed view around 
the entire vessel. More details of the Langseth can be found in the IHA 
application.

Acoustic Source Specifications

Seismic Airguns
    The Langseth will deploy a 36-airgun array, consisting of two 18 
airgun sub-arrays. Each sub-array will have a volume of approximately 
3,300 cubic inches (in\3\). The airgun array will consist of a mixture 
of Bolt 1500LL and Bolt 1900LLX airguns ranging in size from 40 to 360 
in\3\, with a firing pressure of 1,900 pounds per square inch (psi). 
The 18 airgun sub-arrays will be configured as two identical linear 
arrays or ``strings'' (see Figure 3 and 4 of the IHA application). Each 
string will have 10 airguns, the first and last airguns in the strings 
are spaced 16 m (52.5 ft) apart. Of the 10 airguns, nine airguns in 
each string will be fired simultaneously (1,650 in\3\), whereas the 
tenth is kept in reserve as a spare, to be turned on in case of failure 
of another airgun. The sub-arrays would be fired alternately during the 
survey. The two airgun sub-arrays will be distributed across an area of 
approximately 12 x 16 m (40 x 52.5 ft) behind the Langseth and will be 
towed approximately 140 m (459.3 ft) behind the vessel. Discharge 
intervals depend on both the ship's speed and Two Way Travel Time 
recording intervals. The shot interval will be 37.5 m (123) during the 
study. The shot interval will be relatively short, approximately 15 to 
20 seconds (s) based on an assumed boat speed of 4.5 knots. During 
firing, a brief (approximately 0.1 s) pulse sound is emitted; the 
airguns will be silent during the intervening periods. The dominant 
frequency components range from two to 188 Hertz (Hz).
    The tow depth of the airgun array will be 9 m (29.5 ft) during the 
surveys. Because the actual source is a distributed sound source (18 
airguns) rather than a single point source, the highest sound 
measurable at any location in the water will be less than the nominal 
source level. In addition, the effective source level for sound 
propagating in near-horizontal directions will be substantially lower 
than the nominal omni-directional source level applicable to downward 
propagation because of the directional nature of the sound from the 
airgun array (i.e., sound is directed downward). Figure 3 of the IHA 
application shows one linear airgun array or ``string'' with ten 
airguns. Figure 4 of the IHA application diagrams the airgun array and 
streamer deployment from the Langseth.
Hydrophone Streamer
    Acoustic signals will be recorded using a system array of four 
hydrophone streamers, which would be towed behind the Langseth. Each 
streamer would consist of Sentry Solid Streamer Sercel cable 
approximately 6 km (3.2 nmi) long. The streamers are attached by floats 
to a diverter cable, which keeps the streamer spacing at approximately 
100 to 150 m (328 to 492 ft) apart.
    Seven hydrophones will be present along each streamer for acoustic 
measurement. The hydrophones will consist of a mixture of Sonardyne 
Transceivers. Each streamer will contain three groups of paired 
hydrophones, with each group approximately 2,375 m (7,800 ft) apart. 
The hydrophones within each group will be approximately 300 m (984 ft) 
apart. One additional hydrophone will be located on the tail buoy 
attached to the end of the streamer cable. In addition, one Sonardyne 
Transducer will be attached to the airgun array. Compass birds will be 
used to keep the streamer cables and hydrophones at a depth of 
approximately 10 m (32.8 ft). One compass bird will be placed at the 
front end of each streamer as well as periodically along the streamer. 
Figure 4 of the IHA application depicts the configuration of both the 
streamer and airgun array used by the Langseth. Details regarding the 
hydrophone streamer and acoustic recording equipment specifications are 
included in Table 1 of the IHA application.

Metrics Used in This Document

    This section includes a brief explanation of the sound measurements 
frequently used in the discussions of acoustic effects in this 
document. Sound pressure is the sound force per unit area, and is 
usually measured in micropascals ([mu]Pa), where 1 pascal (Pa) is the 
pressure resulting from a force of one newton exerted over an area of 
one square meter. Sound pressure level (SPL) is expressed as the ratio 
of a measured sound pressure and a reference level. The commonly used 
reference pressure level in underwater acoustics is 1 [mu]Pa, and the 
units for SPLs are dB re: 1 [mu]Pa. SPL (in decibels [dB]) = 20 log 
(pressure/reference pressure).
    SPL is an instantaneous measurement and can be expressed as the 
peak, the peak-peak (p-p), or the root mean square (rms). Root mean 
square, which is the square root of the arithmetic average of the 
squared instantaneous pressure values, is typically used in discussions 
of the effects of sounds on vertebrates and all references to SPL in 
this document refer to the root mean square unless otherwise noted. SPL 
does not take the duration of a sound into account.

Characteristics of the Airgun Pulses

    Airguns function by venting high-pressure air into the water which 
creates an air bubble. The pressure signature of an individual airgun 
consists of a sharp rise and then fall in pressure, followed by several 
positive and negative pressure excursions caused by the oscillation of 
the resulting air bubble. The oscillation of the air bubble transmits 
sounds downward through the seafloor and the amount of sound 
transmitted in the near horizontal directions is reduced. However, the 
airgun array also emits sounds that travel horizontally toward non-
target areas.
    The nominal source levels of the airgun arrays used by L-DEO and 
PG&E on the Langseth are 236 to 265 dB re 1 [mu]Pa (p-p) and the rms 
value for a given airgun pulse is typically 16 dB re 1 [mu]Pa lower 
than the peak-to-peak value (Greene, 1997; McCauley et al., 1998, 
2000a). The specific source output for the 18 airgun array is 252 dB 
(peak) and 259 dB (p-p). However, the difference between rms and peak 
or peak-to-peak values for a given pulse depends on the frequency 
content and duration of the pulse, among other factors.
    Accordingly, L-DEO and PG&E have predicted the received sound 
levels in relation to distance and direction from the 18 airgun array 
and the single Bolt

[[Page 58260]]

1900LL 40 in\3\ airgun, which will be used during power-downs. A 
detailed description of L-DEO and PG&E's modeling for this survey's 
marine seismic source arrays for protected species mitigation is 
provided in Appendix A of the IHA application and NSF's EA. Appendix A 
(GSI Technical Memorandum 470-3 and GSI Technical Memorandum 470-2RevB) 
of the IHA application and NSF's EA discusses the characteristics of 
the airgun pulses. NMFS refers the reviewers to the IHA application and 
EA documents for additional information.

Predicted Sound Levels for the Airguns

    To determine exclusion zones for the airgun array to be used off 
the central coast of California, the noise modeling for the proposed 3D 
seismic survey is based on the results of mathematical modeling 
conducted by Greeneridge Sciences, Inc. (2011). The model results are 
based upon the airgun specifications provided for the Langseth and 
seafloor characteristics available for the project area. Specifically, 
L-DEO's predicted sound contours were used to estimate pulse sound 
level extrapolated to an effective distance of one meter, effectively 
reducing the multi-element array to a point source. Such a description 
is valid for descriptions of the far field sounds, i.e., at distances 
that are long compared to the dimensions of the array and the sound 
wavelength. Greeneridge Sciences, Inc. did not account for near-field 
effects. However, since the vast majority of acoustic energy radiated 
by an airgun array is below 500 Hz and the near field is small for the 
given airgun array at these frequencies (the radius of the near field 
around the array is 21 m [68.9 ft] or less for frequencies below 500 
Hz), near-field effects are considered minimal.
    The sound propagation from the airgun array was modeled in 
accordance with physical description of sound propagation and depends 
on waveguide characteristics, including water depth, water column sound 
velocity profile, and geoacoustic parameters of the ocean bottom. For 
the sound propagation model, Greeneridge Sciences, Inc. relied on 
variants of the U.S. Navy's range-dependent Acoustic Model. Greeneridge 
Sciences, Inc. modeled three 2D (range versus depth) propagation paths, 
each with range-dependent (i.e., range-varying) bathymetry and range-
independent geoacoustic profiles. The resulting received sound levels 
at a receiver depth of 6 m (19.7 ft) and across range were then 
``smoothed'' via least-squares regression. The monotonically-decreasing 
regression equations yielded the estimated safety radii.
    The accuracy of the sound field predicted by the acoustic 
propagation model is limited by the quality and resolution of the 
available environmental data. Greeneridge Sciences, Inc. used 
environmental information provided by the client for the proposed 
survey area, specifically, bathymetry data, a series of measured water 
column sound speed profiles, and descriptive sediment and basement 
properties. Greeneridge Sciences, Inc. used two geoacoustic profiles 
for its three propagation paths: One for the upslope propagation path 
(sand overlaying sandstone) and one for the downslope and alongshore 
propagation paths (silt overlaying sandstone)
    L-DEO and PG&E have used these calculated values to determine 
exclusion zones for the 18 airgun array and previously modeled 
measurements by L-DEO for the single airgun, to designate exclusion 
zones for purposes of mitigation, and to estimate take for marine 
mammals off the central coast of California. A detailed description of 
the modeling effort is provided in Appendix A of NSF's EA.
    Using the model (airgun array and single airgun), Table 1 (below) 
shows the distances at which three rms sound levels are expected to be 
received from the 18 airgun array and a single airgun. To avoid the 
potential for injury or permanent physiological damage (Level A 
harassment), NMFS (1995, 2000) has concluded that cetaceans and 
pinnipeds should not be exposed to pulsed underwater noise at received 
levels exceeding 180 dB re: 1 [micro]Pa and 190 dB re: 1 [micro]Pa, 
respectively. L-DEO and PG&E used these levels to establish the 
exclusion zones. If marine mammals are detected within or about to 
enter the appropriate exclusion zone, the airguns will be powered-down 
(or shut-down, if necessary) immediately. NMFS also assumes that marine 
mammals exposed to levels exceeding 160 dB re: 1 [micro]Pa may 
experience Level B harassment.
    Table 1 summarizes the predicted distances at which sound levels 
(160, 180, and 190 dB [rms]) are expected to be received from the 18 
airgun array and a single airgun operating in upslope (inshore), 
downslope (offshore), and alongshore depths. For the proposed project, 
L-DEO and PG&E plan to use the upslope distance (inshore) for the 160 
dB (6,210 m [20,374 ft]) and 180 dB (1,010 m [3,313.7 ft], and 
alongshore distance for the 190 dB (320 m [1,049.9 ft]), for the 
determination of the buffer and exclusion zones since this represents 
the largest and therefore most conservative distances determined by the 
Greeneridge Sciences, Inc. modeling.
    Table 1. Modeled (array) or predicted (single airgun) distances to 
which sound levels >= 190, 180, and 160 dB re: 1 [mu]Pa (rms) could be 
received in upslope, downslope, and alongshore propagation paths during 
the proposed survey off the central coast of California, November to 
December, 2012.

----------------------------------------------------------------------------------------------------------------
                                                  Predicted RMS radii distances for 18 airgun array
Sound pressure level  (SPL) (dB re -----------------------------------------------------------------------------
           1 [micro]Pa)                Upslope distance      Downslope distance
                                          (inshore)              (offshore)             Alongshore distance
----------------------------------------------------------------------------------------------------------------
190 dB............................  250 m (0.13 nmi).....  280 m (0.15 nmi).....  320 m (0.17 nmi)
180 dB............................  1,010 m (0.55 nmi)...  700 m (0.38 nmi).....  750 m (0.40 nmi)
160 dB............................  6,210 m (3.35 nmi)...  4,450 m (2.40 nmi)...  4,100 m (2.21 nmi)
----------------------------------------------------------------------------------------------------------------


----------------------------------------------------------------------------------------------------------------
                                                   Predicted RMS radii distances for single airgun
 Sound pressure level  (SPL) (dB re ----------------------------------------------------------------------------
            1 [micro]Pa)              Shallow water (< 100     Intermediate water
                                               m)               (100 to 1,000 m)        Deep Water (> 1,000 m)
----------------------------------------------------------------------------------------------------------------
190 dB.............................  150 m (0.08 nmi)......  18 m (< 0.01 nmi).....  12 m (< 0.01 nmi)
180 dB.............................  296 m (0.16 nmi)......  60 m (0.03 nmi).......  40 m (0.02 nmi)
160 dB.............................  1,050 m (0.57 nmi)....  578 m (0.31 nmi)......  385 m (0.21 nmi)
----------------------------------------------------------------------------------------------------------------


[[Page 58261]]

    Along with the airgun operations, two additional acoustical data 
acquisition systems will be operated from the Langseth continuously 
during the survey. The ocean floor will be mapped with the Kongsberg EM 
122 multibeam echosounder and a Knudsen 320B sub-bottom profiler. These 
sound sources will be operated continuously from the Langseth 
throughout the cruise.

Multibeam Echosounder

    The Langseth will operate a Kongsberg EM 122 multibeam echosounder 
concurrently during airgun operations to map characteristics of the 
ocean floor. The hull-mounted multibeam echosounder emits brief pulses 
of sound (also called a ping) (10.5 to 13, usually 12 kHz) in a fan-
shaped beam that extends downward and to the sides of the ship. The 
transmitting beamwidth is 1[deg] or 2[deg] fore-aft and 150[deg] 
athwartship and the maximum source level is 242 dB re: 1 [mu]Pa.
    Each ping consists of eight (in water greater than 1,000 m) or four 
(less than 1,000 m) successive, fan-shaped transmissions, each 
ensonifying a sector that extends 1[deg] fore-aft. Continuous-wave 
pulses increase from 2 to 15 milliseconds (ms) long in water depths up 
to 2,600 m (8,350.2 ft), and frequency modulated (FM) chirp pulses up 
to 100 ms long are used in water greater than 2,600 m. The successive 
transmissions span an overall cross-track angular extent of about 
150[deg], with 2 ms gaps between the pulses for successive sectors (see 
Table 2 of the IHA application).

Sub-Bottom Profiler

    The Langseth will also operate a Knudsen Chirp 320B sub-bottom 
continuously throughout the cruise simultaneously with the multibeam 
echosounder to map and provide information about the sedimentary 
features and bottom topography. The beam is transmitted as a 27[deg] 
cone, which is directed downward by a 3.5 kHz transducer in the hull of 
the Langseth. The maximum output is 1 kilowatt (kW), but in practice, 
the output varies with water depth. The pulse interval is one second, 
but a common mode of operation is to broadcast five pulses at one 
second intervals followed by a 5-second pause.
    Both the multibeam echosounder and sub-bottom profiler are operated 
continuously during survey operations. Given the relatively shallow 
water depths of the survey area (20 to 300 m [66 to 984 ft]), the 
number of pings or transmissions would be reduced from 8 to 4, and the 
pulse durations would be reduced from 100 ms to 2 to 15 ms for the 
multibeam echosounder. Power levels of both instruments would be 
reduced from maximum levels to account for water depth. Actual 
operating parameters will be established at the time of the survey.
    NMFS expects that acoustic stimuli resulting from the proposed 
operation of the single airgun or the 18 airgun array has the potential 
to harass marine mammals. NMFS does not expect that the movement of the 
Langseth, during the conduct of the seismic survey, has the potential 
to harass marine mammals because of the relatively slow operation speed 
of the vessel (approximately 4.6 knots [kts]; 8.5 km/hr; 5.3 mph) 
during seismic acquisition.

Gravimeter

    The Langseth will employ a Bell Aerospace BGM-3 gravimeter system 
(see Figure 5 of the IHA application) to measure very tiny fractional 
changes within the Earth's gravity caused by nearby geologic 
structures, the shape of the Earth, and by temporal tidal variations. 
The gravimeter has been specifically designed to make precision 
measurements in a high motion environment. Precision gravity 
measurements are attained by the use of the highly accurate Bell 
Aerospace Model XI inertial grade accelerometer.

Magnetometer

    The Langseth will employ a Bell Aerospace BGM-3 geometer, which 
contains a model G-882 cesium-vapor marine magnetometer (see Figure 6 
of the IHA application). Magnetometers measure the strength and/or 
direction of a magnetic field, generally in units of nanotesla in order 
to detect and map geologic formations. These data would enhance earlier 
marine magnetic mapping conducted by the U.S. Geologic Survey (Sliter 
et al., 2009).
    The G-882 is designed for operation from small vessels for shallow 
water surveys as well as for the large survey vessels for deep tow 
applications. Power may be supplied from a 24 to 30 VDC battery power 
or a 110/220 VAC power supply. The standard G-882 tow cable includes a 
Vectran strength member and can be built to up to 700 m (2,297 ft) (no 
telemetry required). The shipboard end of the tow cable is attached to 
a junction box or onboard cable. Output data are recorded on a computer 
with an RS-232 serial port.
    Both the gravimeter and magnetometers are ``passive'' instruments 
and do not emit sounds, impulses, or signals, and are not expected to 
affect marine mammals.

Nearshore and Onshore Survey Operations

    To collect deep seismic data in water depths that are not 
accessible by the Langseth (less than 25 m [82 ft]), seafloor geophones 
and both offshore and onshore seismic sources will be used. The 
currently proposed locations for the seafloor geophone lines between 
Point Buchon and Point San Luis are shown in Figure 7 of the IHA 
application.
    Twelve Fairfield Z700 marine nodes would be placed on the seafloor 
along two nearshore survey routes as a pilot test prior to the full 
deployment of 600 nodes scheduled for 2013. The northern route (Crowbar 
Beach) traverses the Point Buchon MPA north of Diablo Canyon Power 
Plant. The southern route (either Green Peak or Deer Canyon) is located 
south of the Diablo Canyon Power Plant. The approximate locations of 
the proposed nodal routes are depicted in Figure 7 of the IHA 
application. Six nodes would be placed at 500 m (1,640.4 ft) intervals 
along each route for a total length of 3 km (1.9 mi). Maximum water 
depth ranges from 70 m (229.7 ft) (Crowbar) to 30 m (98.4 ft) (Deer 
Canyon). Marine nodes would be deployed using a vessel and (in some 
locations) divers and will be equipped with ultra-short baseline 
acoustic tracking system to position and facilitate recovery of each 
node. The tracking equipment will be used to provide underwater 
positioning of a remotely operated vehicle during deployment and 
recovery of the nodes.
    The seafloor equipment will be in place for the duration of the 
data collection for the offshore 3D high energy seismic surveys plus 
deployment and recovery time. Node deployment will be closely 
coordinated with both offshore and onshore survey operations to ensure 
survey activities are completed before the projected batter life of 45 
days is exceeded. PG&E anticipates using a locally-available vessel to 
deploy and retrieve the geophones. The vessel would be a maximum of 50 
m in length. The Michael Uhl, which is locally available, its sister 
vessel, or a vessel of similar size and engine specification, is 
proposed for this purpose.
    Onshore, a linear array of ZL and nodals will be deployed along a 
single route on the Morro Strand to record onshore sound transmitted 
from the offshore airgun surveys. Route location is shown in Figure 9 
of the IHA application. Ninety nodes would be placed at 100 m (328 ft) 
intervals along the strand for a total route length of approximately 9 
km (5.6 mi). The

[[Page 58262]]

autonomous, nodal, cable-less recording devices (see Figure 9 of the 
IHA application) would be deployed by foot into the soil adjacent to 
existing roads, trails, and beaches. The nodal systems are carried in 
backpacks and pressed into the ground at each receiver point. Each 
nodal would be removed following completion of the data collection. 
PG&E estimates that the onshore receiver activities would be conducted 
over a 2 to 3 day period, concurrent with the offshore surveys. The 
onshore receivers would record the offshore sound sources during the 
seismic operations. Figure 10 of the IHA application depicts the area 
where the onshore receivers are proposed to be placed along the Morro 
Strand. PG&E and NMFS have determined that onshore activities are 
unlikely to impact marine mammals, including pinnipeds at haul-outs and 
rookeries, in the proposed action area.
    More information on the vessels, equipment, and personnel 
requirements proposed for use in the offshore survey can be found in 
sections 1.4 and 1.5 of the IHA application.

Dates, Duration, and Specified Geographic Region

    The proposed project located offshore of central California would 
have a total duration of approximately 49.25 operational days occurring 
during the November through December, 2012 timeframe, which will 
include approximately 24 days of active seismic airgun operations. 
Mobilization will initiate on October 15, 2012, with active airgun 
surveys taking place from November 1 through December 31, 2012. Below 
is an estimated schedule for the proposed project based on the use of 
the Langseth as the primary survey vessel (the total number of days is 
based on adding the non-concurrent tasks):
     Mobilization to project site--6 days;
     Initial equipment deployment--3 days (includes offshore 
geophone deployment);
     Pre-activity marine mammal surveys--5 days (concurrent 
with offshore deployment activities);
     Onshore geophone deployment--2 to 3 days (concurrent with 
offshore deployment activities);
     Equipment calibration and sound check (i.e., sound source 
verification)--5 days;
     Seismic survey--23.25 days (Survey Box 4 will be surveyed 
first followed by Survey Box 2, 24/7 operations in all areas);
     Survey Box 4 (survey area within Estero Bay)--9.25 days;
     Survey Box 2 (survey area from Estero Bay to offshore to 
the mouth of the Santa Maria River)--14 days;
     Streamer and airgun preventative maintenance--2 days;
     Additional shut-downs (marine mammal presence, crew 
changes, and unanticipated weather delays)--4 days;
     Demobilization--6 days.
    Placement of the onshore receiver lines would be completed prior to 
the start of offshore survey activities and would remain in place until 
the offshore survey can be completed. Some minor deviation from this 
schedule is possible, depending on logistics and weather (i.e., the 
cruise may depart earlier or be extended due to poor weather; there 
could be additional days of seismic operations if collected data are 
deemed to be of substandard quality).
    The latitude and longitude for the bounds of the two survey boxes 
are:

Survey Box 4:

35[deg] 25' 21.7128'' North, 120[deg] 57' 44.7001'' West
35[deg] 20' 16.0648'' North, 121[deg] 9' 24.1914'' West
35[deg] 18' 38.3096'' North, 120[deg] 53' 29.9525'' West
35[deg] 14' 42.003'' North, 121[deg] 3' 36.9513'' West

Survey Box 2:

34[deg] 57' 43.3388'' North, 120[deg] 45' 12.8318'' West
34[deg] 55' 40.383'' North, 120[deg] 48' 59.3101'' West
35[deg] 25' 40.62'' North, 121[deg] 00' 27.12'' West
35[deg] 23' 57.26'' North, 121[deg] 04' 37.28'' West

Description of the Marine Mammals in the Area of the Proposed Specified 
Activity

    Thirty-six marine mammal species (29 cetaceans [whales, dolphins, 
and porpoises], 6 pinnipeds [seals and sea lions], and 1 fissiped) are 
known to or could occur off the central coast of California study area. 
Several of these species are listed as endangered under the U.S. 
Endangered Species Act of 1973 (ESA; 16 U.S.C. 1531 et seq.), including 
the North Pacific right (Eubalaena japonica), humpback (Megaptera 
novaeangliae), sei (Balaenoptera borealis), fin (Balaenoptera 
physalus), blue (Balaenoptera musculus), and sperm (Physeter 
macrocephalus) whales. The Guadalupe fur seal (Arctocephalus townsendi) 
and Eastern stock of Steller sea lion (Eumetopias jubatus), and 
southern sea otter (Enhydra lutris nereis) are listed as threatened 
under the ESA. The southern sea otter is the one marine mammal species 
mentioned in this document that is managed by the U.S. Fish and 
Wildlife Service (USFWS) and is not considered further in this 
analysis; all others are managed by NMFS. While in their range, North 
Pacific right, sei, and sperm whale sightings are uncommon in the 
proposed project area, and have a low likelihood of occurrence during 
the proposed seismic survey. Similarly, the proposed project area is 
generally north of the range of the Guadalupe fur seal. Table 2 (below) 
presents information on the abundance, distribution, population status, 
conservation status, and population trend of the species of marine 
mammals that may occur in the proposed study area during November to 
December, 2012.
    Table 2. The habitat, regional abundance, and conservation status 
of marine mammals that may occur in or near the proposed seismic survey 
area off the central coast of California. (See text and Table 4 in L-
DEO and PG&E's application for further details.)

--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                          Population estimate
             Species                      Habitat            \3\ (minimum)            ESA \1\              MMPA \2\             Population trend \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mysticetes:
    North Pacific right whale      Pelagic and coastal.  NA (18 to 21)--       EN..................  D...................  No information available
     (Eubalaena japonica).                                Eastern North
                                                          Pacific stock.
    Gray whale (Eschrichtius       Coastal, shallow      19,126 (18,017)--     DL--Eastern North     NC--Eastern North     Increasing over past several
     robustus).                     shelf.                Eastern North         Pacific stock EN--    Pacific stock D--     decades
                                                          Pacific stock.        Western North         Western North
                                                                                Pacific stock.        Pacific stock.
    Humpback whale (Megaptera      Mainly nearshore,     2,043 (1,878)--       EN..................  D...................  Increasing
     novaeangliae).                 banks.                California/Oregon/
                                                          Washington stock.
    Minke whale (Balaenoptera      Pelagic and coastal.  478 (202)--           NL..................  NC..................  No information available
     acutorostrata).                                      California/Oregon/
                                                          Washington stock.

[[Page 58263]]

 
    Sei whale (Balaenoptera        Primarily offshore,   126 (83)--Eastern     EN..................  D...................  No information available
     borealis).                     pelagic.              North Pacific stock.
    Fin whale (Balaenoptera        Continental slope,    3,044 (2,624)--       EN..................  D...................  Unable to determine
     physalus).                     pelagic.              California/Oregon/
                                                          Washington stock.
    Blue whale (Balaenoptera       Pelagic, shelf,       2,497 (2,046)--       EN..................  D...................  Unable to determine
     musculus).                     coastal.              Eastern North
                                                          Pacific stock.
Odontocetes:
    Sperm whale (Physeter          Pelagic, deep sea...  971 (751)--           EN..................  D...................  Variable
     macrocephalus).                                      California/Oregon/
                                                          Washington stock.
    Pygmy sperm whale (Kogia       Deep waters off the   579 (271)--           NL..................  NC..................  No information available
     breviceps).                    shelf.                California/Oregon/
                                                          Washington stock.
    Dwarf sperm whale (Kogia       Deep waters off the   NA--California/       NL..................  NC..................  No information available
     sima).                         shelf.                Oregon/Washington
                                                          stock.
    Cuvier's beaked whale          Pelagic.............  2,143 (1,298)--       NL..................  NC..................  No information available
     (Ziphius cavirostris).                               California/Oregon/
                                                          Washington stock.
    Baird's beaked whale           Pelagic.............  907 (615)--           NL..................  NC..................  No information available
     (Berardius bairdii).                                 California/Oregon/
                                                          Washington stock.
    Mesoplodon beaked whale        Pelagic.............  1,204 (576)--         NL..................  NC..................  No information available
     (includes Blainville's                               California/Oregon/
     beaked whale [M.                                     Washington stock.
     densirostris], Perrin's
     beaked whale [M. perrini],
     Lesser beaked whale [M.
     peruvianis], Stejneger's
     beaked whale [M.
     stejnegeri], Gingko-toothed
     beaked whale [M.
     gingkodens], Hubbs' beaked
     whale [M. carlhubbsi]).
    Bottlenose dolphin (Tursiops   Coastal, oceanic,     1,006 (684)--         NL..................  NC D--Western North   No information available
     truncatus).                    shelf break.          California/Oregon/                          Atlantic coastal.     Stable
                                                          Washington stock
                                                          323 (290)--
                                                          California Coastal
                                                          stock.
    Striped dolphin (Stenella      Off continental       10,908 (8,231)--      NL..................  NC..................  Unable to determine
     coeruleoalba).                 shelf.                California/Oregon/
                                                          Washington stock.
    Short-beaked common dolphin    Shelf, pelagic,       411,211 (343,990)--   NL..................  NC..................  Variable with oceanographic
     (Delphinus delphis).           seamounts.            California/Oregon/                                                conditions
                                                          Washington stock.
    Long-beaked common dolphin     Coastal, on           27,046 (17,127)--     NL..................  NC..................  No information available,
     (Delphinus capensis).          continental shelf.    California stock.                                                 variable with oceanographic
                                                                                                                            conditions
    Pacific white-sided dolphin    Offshore, slope.....  26,930 (21,406)--     NL..................  NC..................  No information available
     (Lagenorhynchus obliquidens).                        California/Oregon/
                                                          Washington stock.
    Northern right whale dolphin   Slope, offshore       8,334 (6,019)--       NL..................  NC..................  Unable to determine
     (Lissodelphis borealis).       waters.               California/Oregon/
                                                          Washington stock.
    Risso's dolphin (Grampus       Deep water,           6,272 (4,913)--       NL..................  NC..................  Unable to determine
     griseus).                      seamounts.            California/Oregon/
                                                          Washington stock.
    Killer whale (Orcinus orca)..  Pelagic, shelf,       240 (162)--Eastern    NL EN--Southern       NC D--Southern        No information available, No
                                    coastal.              North Pacific         resident.             resident, AT1         information available,
                                                          Offshore stock 346                          transient.            Declining, Increased and
                                                          (346)--Eastern                                                    slowing
                                                          North Pacific
                                                          Transient stock 354
                                                          (354)--West Coast
                                                          Transient stock.
    Short-finned pilot whale       Pelagic, shelf        760 (465)--           NL..................  NC..................  Unable to determine
     (Globicephala macrorhynchus).  coastal.              California/Oregon/
                                                          Washington stock.
    Harbor porpoise (Phocoena      Coastal and inland    2,044 (1,478)--Morro  NL..................  NC..................  Increasing
     phocoena).                     waters.               Bay stock.
    Dall's porpoise (Phocoenoides  Shelf, slope,         42,000 (32,106)--     NL..................  NC..................  No information available
     dalli).                        offshore.             California/Oregon/
                                                          Washington stock.
Pinnipeds:
    California sea lion (Zalophus  Coastal, shelf......  296,750 (153,337)--   NL..................  NC..................  Increasing
     californianus).                                      U.S. stock.
    Steller sea lion (Eumetopias   Coastal, shelf......  49,685 (42,366)--     T...................  D...................  Decreasing in California
     jubatus).                                            Western stock
                                                          58,334 to 72,223
                                                          (52,847)--Eastern
                                                          stock.

[[Page 58264]]

 
    Guadalupe fur seal             Coastal, shelf......  7,408 (3,028)--       T...................  D...................  Increasing
     (Arctocephalus townsendi).                           Mexico stock.
    Northern fur seal              Pelagic, offshore...  9,968 (5,395)--San    NL..................  D...................  Increasing
     (Callorhinus ursinus).                               Miguel Island stock.
    Northern elephant seal         Coastal, pelagic in   124,000 (74,913)--    NL..................  NC..................  Increasing
     (Mirounga angustirostris).     migration.            California Breeding
                                                          stock.
    Pacific harbor seal (Phoca     Coastal.............  30,196 (26,667)--     NL..................  NC..................  Increasing
     vitulina richardsi).                                 California stock.
Fissipeds:
    Southern sea otter (Enhydra    Coastal.............  2,711--California     T...................  D...................  Increasing
     lutris nereis).                                      stock.
--------------------------------------------------------------------------------------------------------------------------------------------------------
NA = Not available or not assessed.
\1\ U.S. Endangered Species Act: EN = Endangered, T = Threatened, DL = Delisted, NL = Not listed.
\2\ U.S. Marine Mammal Protection Act: D = Depleted, NC = Not Classified.
\3\ NMFS Stock Assessment Reports.

    In the Pacific Ocean, harbor porpoises are found in coastal and 
inland waters from California to Alaska and across to Kamchatka and 
Japan (Gakin, 1984). Harbor porpoises appear to have more restricted 
movements along the western coast of the continental United States, 
than along the eastern coast, with some regional differences within 
California. Based on genetic differences that showed small-scale 
subdivision within the U.S. portion of its range, California coast 
stocks were re-evaluated and the stock boundaries were revised. The 
boundaries (i.e., range) for the Morro Bay stock of harbor porpoises 
are from Point Sur to Point Conception, California. The vast majority 
of harbor porpoise in California are within the 0 to 92 m (0 to 301.8 
ft) depth, however, a smaller percentage can be found between the 100 
to 200 m (328 to 656.2 ft) isobaths. A systematic ship survey of depth 
strata out to 90 m (295.3 ft) in northern California showed that harbor 
porpoise abundance declined significantly in waters deep than 60 m 
(196.9 ft) (Caretta et al., 2001b). Additionally, individuals of the 
Morro Bay stock appear to be concentrated at significantly higher 
densities in one specific area of their overall range, which NMFS is 
referring to as their ``core range,'' and density is much lower to both 
the North and South of this area. This core range has the larger number 
of harbor porpoise sightings and the largest number of harbor porpoise 
individuals observed during line-transect surveys and is defined for 
the purposes of this analysis from 34.755[deg] through 35.425[deg] 
North latitude (see transects 3 to 6 in Table 1 of Appendix B of the 
IHA application). For the Morro Bay stock, the best estimate of 
abundance is 2,044 animals and the minimum population estimate is 1,478 
animals. There has been an increasing trend in harbor porpoise 
abundance in Morro Bay since 1988. The observed increase in abundance 
estimates for this stock since 1988 implies an annual growth rate of 
approximately 13%. Appendix B of the IHA application includes more 
detailed information on the density figures and calculations for the 
Morro Bay stock of harbor porpoise. Figure 1 of Appendix B shows the 
fine-scale density (including core habitat of higher density) as well 
as the proposed tracklines of Survey Box 4 and Survey Box 2.
    Refer to sections 3 and 4 of L-DEO and PG&E's application for 
detailed information regarding the abundance and distribution, 
population status, and life history and behavior of these other marine 
mammal species and their occurrence in the proposed project area. The 
application also presents how L-DEO and PG&E calculated the estimated 
densities for the marine mammals in the proposed survey area. NMFS has 
reviewed these data and determined them to be the best available 
scientific information for the purposes of the proposed IHA.

Potential Effects on Marine Mammals

    Acoustic stimuli generated by the operation of the airguns, which 
introduce sound into the marine environment, may have the potential to 
cause Level B harassment of marine mammals in the proposed survey area. 
The effects of sounds from airgun operations might include one or more 
of the following: tolerance, masking of natural sounds, behavioral 
disturbance, temporary or permanent hearing impairment, or non-auditory 
physical or physiological effects (Richardson et al., 1995; Gordon et 
al., 2004; Nowacek et al., 2007; Southall et al., 2007). Permanent 
hearing impairment, in the unlikely event that it occurred, would 
constitute injury, but temporary threshold shift (TTS) is not an injury 
(Southall et al., 2007). Although the possibility cannot be entirely 
excluded, it is unlikely that the proposed project would result in any 
cases of temporary or permanent hearing impairment, or any significant 
non-auditory physical or physiological effects. Based on the available 
data and studies described here, some behavioral disturbance is 
expected, especially for the Morro Bay harbor porpoise stock, which 
could potentially be displaced from their core habitat during all or 
part of the seismic survey or longer. A more comprehensive review of 
these issues can be found in the ``Programmatic Environmental Impact 
Statement/Overseas Environmental Impact Statement prepared for Marine 
Seismic Research that is funded by the National Science Foundation and 
conducted by the U.S. Geological Survey'' (NSF/USGS, 2011).

Tolerance

    Richardson et al. (1995) defines tolerance as the occurrence of 
marine mammals in areas where they are exposed to human activities or 
man-made noise. In many cases, tolerance develops by the animal 
habituating to the stimulus (i.e., the gradual waning of responses to a 
repeated or ongoing stimulus) (Richardson, et al., 1995; Thorpe, 1963), 
but because of ecological or physiological requirements, many marine 
animals may need to remain in areas where they are exposed to chronic 
stimuli (Richardson, et al., 1995).
    Numerous studies have shown that pulsed sounds from airguns are 
often readily detectable in the water at distances of many kilometers. 
Several studies have shown that marine mammals at distances more than a 
few kilometers from operating seismic vessels often show no apparent 
response. That is often true even in cases when the pulsed sounds must 
be readily audible to the animals based on measured received levels and 
the hearing sensitivity of the marine mammal group. Although various 
baleen whales and toothed whales, and (less frequently) pinnipeds have 
been shown to react behaviorally to airgun pulses under some 
conditions, at other times marine mammals of all three types have shown 
no overt reactions. The

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relative responsiveness of baleen and toothed whales are quite 
variable.

Masking

    The term masking refers to the inability of a subject to recognize 
the occurrence of an acoustic stimulus as a result of the interference 
of another acoustic stimulus (Clark et al., 2009). Introduced 
underwater sound may, through masking, reduce the effective 
communication distance of a marine mammal species if the frequency of 
the source is close to that used as a signal by the marine mammal, and 
if the anthropogenic sound is present for a significant fraction of the 
time (Richardson et al., 1995).
    Masking effects of pulsed sounds (even from large arrays of 
airguns) on marine mammal calls and other natural sounds are expected 
to be limited. Because of the intermittent nature and low duty cycle of 
seismic airgun pulses, animals can emit and receive sounds in the 
relatively quiet intervals between pulses. However, in some situations, 
reverberation occurs for much or the entire interval between pulses 
(e.g., Simard et al., 2005; Clark and Gagnon, 2006) which could mask 
calls. Some baleen and toothed whales are known to continue calling in 
the presence of seismic pulses, and their calls can usually be heard 
between the seismic pulses (e.g., Richardson et al., 1986; McDonald et 
al., 1995; Greene et al., 1999; Nieukirk et al., 2004; Smultea et al., 
2004; Holst et al., 2005a,b, 2006; and Dunn and Hernandez, 2009). 
However, Clark and Gagnon (2006) reported that fin whales in the North 
Atlantic Ocean went silent for an extended period starting soon after 
the onset of a seismic survey in the area. Similarly, there has been 
one report that sperm whales ceased calling when exposed to pulses from 
a very distant seismic ship (Bowles et al., 1994). However, more recent 
studies found that they continued calling in the presence of seismic 
pulses (Madsen et al., 2002; Tyack et al., 2003; Smultea et al., 2004; 
Holst et al., 2006; and Jochens et al., 2008). Dilorio and Clark (2009) 
found evidence of increased calling by blue whales during operations by 
a lower-energy seismic source (i.e., sparker). Dolphins and porpoises 
commonly are heard calling while airguns are operating (e.g., Gordon et 
al., 2004; Smultea et al., 2004; Holst et al., 2005a, b; and Potter et 
al., 2007). The sounds important to small odontocetes are predominantly 
at much higher frequencies than are the dominant components of airgun 
sounds, thus limiting the potential for masking.
    Pinnipeds have the most sensitive hearing and/or produce most of 
their sounds at frequencies higher than the dominant components of 
airgun sound, but there is some overlap in the frequencies of the 
airgun pulses and the calls. However, the intermittent nature of airgun 
pulses presumably reduces the potential for masking
    Marine mammals are thought to be able to compensate for masking by 
adjusting their acoustic behavior through shifting call frequencies, 
increasing call volume, and increasing vocalization rates. For example, 
blue whales are found to increase call rates when exposed to noise from 
seismic surveys in the St. Lawrence Estuary (Dilorio and Clark, 2009). 
The North Atlantic right whales (Eubalaena glacialis) exposed to high 
shipping noise increased call frequency (Parks et al., 2007), while 
some humpback whales respond to low-frequency active sonar playbacks by 
increasing song length (Miller et al., 2000). In general, NMFS expects 
the masking effects of seismic pulses to be minor, given the normally 
intermittent nature of seismic pulses.

Behavioral Disturbance

    Marine mammals may behaviorally react to sound when exposed to 
anthropogenic noise. Disturbance includes a variety of effects, 
including subtle to conspicuous changes in behavior, movement, and 
displacement. Reactions to sound, if any, depend on species, state of 
maturity, experience, current activity, reproductive state, time of 
day, and many other factors (Richardson et al., 1995; Wartzok et al., 
2004; Southall et al., 2007; Weilgart, 2007). These behavioral 
reactions are often shown as: Changing durations of surfacing and 
dives, number of blows per surfacing, or moving direction and/or speed; 
reduced/increased vocal activities; changing/cessation of certain 
behavioral activities (such as socializing or feeding); visible startle 
response or aggressive behavior (such as tail/fluke slapping or jaw 
clapping); avoidance of areas where noise sources are located; and/or 
flight responses (e.g., pinnipeds flushing into the water from haul-
outs or rookeries). If a marine mammal does react briefly to an 
underwater sound by changing its behavior or moving a small distance, 
the impacts of the change are unlikely to be significant to the 
individual, let alone the stock or population. However, if a sound 
source displaces marine mammals from an important feeding or breeding 
area for a prolonged period, impacts on individuals and populations 
could be significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007).
    The biological significance of many of these behavioral 
disturbances is difficult to predict, especially if the detected 
disturbances appear minor. However, the consequences of behavioral 
modification could be expected to be biologically significant if the 
change affects growth, survival, and/or reproduction. Some of these 
significant behavioral modifications include:
     Change in diving/surfacing patterns (such as those thought 
to be causing beaked whale stranding due to exposure to military mid-
frequency tactical sonar);
     Habitat abandonment due to loss of desirable acoustic 
environment; and
     Cessation of feeding or social interaction.
    The onset of behavioral disturbance from anthropogenic noise 
depends on both external factors (characteristics of noise sources and 
their paths) and the receiving animals (hearing, motivation, 
experience, demography) and is also difficult to predict (Richardson et 
al., 1995; Southall et al., 2007). Given the many uncertainties in 
predicting the quantity and types of impacts of noise on marine 
mammals, it is common practice to estimate how many mammals would be 
present within a particular distance of industrial activities and/or 
exposed to a particular level of sound. In most cases, this approach 
likely overestimates the numbers of marine mammals that would be 
affected in some biologically-important manner.
    Baleen Whales--Baleen whales generally tend to avoid operating 
airguns, but avoidance radii are quite variable (reviewed in Richardson 
et al., 1995; Gordon et al., 2004). Whales are often reported to show 
no overt reactions to pulses from large arrays of airguns at distances 
beyond a few kilometers, even though the airgun pulses remain well 
above ambient noise levels out to much longer distances. However, 
baleen whales exposed to strong noise pulses from airguns often react 
by deviating from their normal migration route and/or interrupting 
their feeding and moving away. In the cases of migrating gray and 
bowhead whales, the observed changes in behavior appeared to be of 
little or no biological consequence to the animals (Richardson, et al., 
1995). They simply avoided the sound source by displacing their 
migration route to varying degrees, but within the natural boundaries 
of the migration corridors.
    Studies of gray, bowhead, and humpback whales have shown that 
seismic pulses with received levels of 160 to 170 dB re 1 [mu]Pa (rms) 
seem to cause obvious avoidance behavior in a

[[Page 58266]]

substantial fraction of the animals exposed (Malme et al., 1986, 1988; 
Richardson et al., 1995). In many areas, seismic pulses from large 
arrays of airguns diminish to those levels at distances ranging from 4 
to 15 km (2.2 to 8.1 nmi) from the source. A substantial proportion of 
the baleen whales within those distances may show avoidance or other 
strong behavioral reactions to the airgun array. Subtle behavioral 
changes sometimes become evident at somewhat lower received levels, and 
studies have shown that some species of baleen whales, notably bowhead, 
gray, and humpback whales, at times, show strong avoidance at received 
levels lower than 160 to 170 dB re 1 [mu]Pa (rms).
    Researchers have studied the responses of humpback whales to 
seismic surveys during migration, feeding during the summer months, 
breeding while offshore from Angola, and wintering offshore from 
Brazil. McCauley et al. (1998, 2000a) studied the responses of humpback 
whales off western Australia to a full-scale seismic survey with a 16 
airgun array (2,678 in\3\) and to a single airgun (20 in\3\) with 
source level of 227 dB re 1 [micro]Pa (p-p). In the 1998 study, they 
documented that avoidance reactions began at 5 to 8 km (2.7 to 4.3 nmi) 
from the array, and that those reactions kept most pods approximately 3 
to 4 km (1.6 to 2.2 nmi) from the operating seismic boat. In the 2000 
study, they noted localized displacement during migration of 4 to 5 km 
(2.2 to 2.7 nmi) by traveling pods and 7 to 12 km (3.8 to 6.5 nmi) by 
more sensitive resting pods of cow-calf pairs. Avoidance distances with 
respect to the single airgun were smaller but consistent with the 
results from the full array in terms of the received sound levels. The 
mean received level for initial avoidance of an approaching airgun was 
140 dB re 1 [mu]Pa (rms) for humpback pods containing females, and at 
the mean closest point of approach distance the received level was 143 
dB re 1 [mu]Pa (rms). The initial avoidance response generally occurred 
at distances of 5 to 8 km (2.7 to 4.3 nmi) from the airgun array and 2 
km (1.1 nmi) from the single airgun. However, some individual humpback 
whales, especially males, approached within distances of 100 to 400 m 
(328 to 1,312 ft), where the maximum received level was 179 dB re 1 
[mu]Pa (rms).
    Data collected by observers during several seismic surveys in the 
Northwest Atlantic showed that sighting rates of humpback whales were 
significantly greater during non-seismic periods compared with periods 
when a full array was operating (Moulton and Holst, 2010). In addition, 
humpback whales were more likely to swim away and less likely to swim 
towards a vessel during seismic vs. non-seismic periods (Moulton and 
Holst, 2010).
    Humpback whales on their summer feeding grounds in southeast Alaska 
did not exhibit persistent avoidance when exposed to seismic pulses 
from a 1.64-L (100 in\3\) airgun (Malme et al., 1985). Some humpbacks 
seemed ``startled'' at received levels of 150 to 169 dB re 1 [mu]Pa. 
Malme et al. (1985) concluded that there was no clear evidence of 
avoidance, despite the possibility of subtle effects, at received 
levels up to 172 dB re 1 [mu]Pa (rms). However, Moulton and Holst 
(2010) reported that humpback whales monitored during seismic surveys 
in the Northwest Atlantic had lower sighting rates and were most often 
seen swimming away from the vessel during seismic periods compared with 
periods when airguns were silent.
    Studies have suggested that South Atlantic humpback whales 
wintering off Brazil may be displaced or even strand upon exposure to 
seismic surveys (Engel et al., 2004). The evidence for this was 
circumstantial and subject to alternative explanations (IAGC, 2004). 
Also, the evidence was not consistent with subsequent results from the 
same area of Brazil (Parente et al., 2006), or with direct studies of 
humpbacks exposed to seismic surveys in other areas and seasons. After 
allowance for data from subsequent years, there was ``no observable 
direct correlation'' between strandings and seismic surveys (IWC, 2007: 
236).
    Reactions of migrating and feeding (but not wintering) gray whales 
to seismic surveys have been studied. Malme et al. (1986, 1988) studied 
the responses of feeding eastern Pacific gray whales to pulses from a 
single 100 in\3\ airgun off St. Lawrence Island in the northern Bering 
Sea. They estimated, based on small sample sizes, that 50 percent of 
feeding gray whales stopped feeding at an average received pressure 
level of 173 dB re 1 [mu]Pa on an (approximate) rms basis, and that 10 
percent of feeding whales interrupted feeding at received levels of 163 
dB re 1 [micro]Pa (rms). Those findings were generally consistent with 
the results of experiments conducted on larger numbers of gray whales 
that were migrating along the California coast (Malme et al., 1984; 
Malme and Miles, 1985), and western Pacific gray whales feeding off 
Sakhalin Island, Russia (Wursig et al., 1999; Gailey et al., 2007; 
Johnson et al., 2007; Yazvenko et al., 2007a, b), along with data on 
gray whales off British Columbia (Bain and Williams, 2006).
    Various species of Balaenoptera (blue, sei, fin, and minke whales) 
have occasionally been seen in areas ensonified by airgun pulses 
(Stone, 2003; MacLean and Haley, 2004; Stone and Tasker, 2006), and 
calls from blue and fin whales have been localized in areas with airgun 
operations (e.g., McDonald et al., 1995; Dunn and Hernandez, 2009; 
Castellote et al., 2010). Sightings by observers on seismic vessels off 
the United Kingdom from 1997 to 2000 suggest that, during times of good 
sightability, sighting rates for mysticetes (mainly fin and sei whales) 
were similar when large arrays of airguns were shooting vs. silent 
(Stone, 2003; Stone and Tasker, 2006). However, these whales tended to 
exhibit localized avoidance, remaining significantly further (on 
average) from the airgun array during seismic operations compared with 
non-seismic periods (Stone and Tasker, 2006). Castellote et al. (2010) 
reported that singing fin whales in the Mediterranean moved away from 
an operating airgun array.
    Ship-based monitoring studies of baleen whales (including blue, 
fin, sei, minke, and humpback whales) in the Northwest Atlantic found 
that overall, this group had lower sighting rates during seismic vs. 
non-seismic periods (Moulton and Holst, 2010). Baleen whales as a group 
were also seen significantly farther from the vessel during seismic 
compared with non-seismic periods, and they were more often seen to be 
swimming away from the operating seismic vessel (Moulton and Holst, 
2010). Blue and minke whales were initially sighted significantly 
farther from the vessel during seismic operations compared to non-
seismic periods; the same trend was observed for fin whales (Moulton 
and Holst, 2010). Minke whales were most often observed to be swimming 
away from the vessel when seismic operations were underway (Moulton and 
Holst, 2010).
    Data on short-term reactions by cetaceans to impulsive noises are 
not necessarily indicative of long-term or biologically significant 
effects. It is not known whether impulsive sounds affect reproductive 
rate or distribution and habitat use in subsequent days or years. 
However, gray whales have continued to migrate annually along the west 
coast of North America with substantial increases in the population 
over recent years, despite intermittent seismic exploration (and much 
ship traffic) in that area for decades (Appendix A in Malme et al., 
1984; Richardson et al.,

[[Page 58267]]

1995; Allen and Angliss, 2010). The western Pacific gray whale 
population did not seem affected by a seismic survey in its feeding 
ground during a previous year (Johnson et al., 2007). Similarly, 
bowhead whales have continued to travel to the eastern Beaufort Sea 
each summer, and their numbers have increased notably, despite seismic 
exploration in their summer and autumn range for many years (Richardson 
et al., 1987; Allen and Angliss, 2010). The history of coexistence 
between seismic surveys and baleen whales suggests that brief exposures 
to sound pulses from any single seismic survey are unlikely to result 
in prolonged effects.
    Toothed Whales--Little systematic information is available about 
reactions of toothed whales to noise pulses. Few studies similar to the 
more extensive baleen whale/seismic pulse work summarized above have 
been reported for toothed whales. However, there are recent systematic 
studies on sperm whales (e.g., Gordon et al., 2006; Madsen et al., 
2006; Winsor and Mate, 2006; Jochens et al., 2008; Miller et al., 
2009). There is an increasing amount of information about responses of 
various odontocetes to seismic surveys based on monitoring studies 
(e.g., Stone, 2003; Smultea et al., 2004; Moulton and Miller, 2005; 
Bain and Williams, 2006; Holst et al., 2006; Stone and Tasker, 2006; 
Potter et al., 2007; Hauser et al., 2008; Holst and Smultea, 2008; 
Weir, 2008; Barkaszi et al., 2009; Richardson et al., 2009; Moulton and 
Holst, 2010).
    Seismic operators and PSOs on seismic vessels regularly see 
dolphins and other small toothed whales near operating airgun arrays, 
but in general there is a tendency for most delphinids to show some 
avoidance of operating seismic vessels (e.g., Goold, 1996 a,b,c; 
Calambokidis and Osmek, 1998; Stone, 2003; Moulton and Miller, 2005; 
Holst et al., 2006; Stone and Tasker, 2006; Weir, 2008; Richardson et 
al., 2009; Barkaszi et al., 2009; Moulton and Holst, 2010). Some 
dolphins seem to be attracted to the seismic vessel and floats, and 
some ride the bow wave of the seismic vessel even when large arrays of 
airguns are firing (e.g., Moulton and Miller, 2005). Nonetheless, small 
toothed whales more often tend to head away, or to maintain a somewhat 
greater distance from the vessel, when a large array of airguns is 
operating than when it is silent (e.g., Stone and Tasker, 2006; Weir, 
2008; Barry et al., 2010; Moulton and Holst, 2010). In most cases, the 
avoidance radii for delphinids appear to be small, on the order of one 
km or less, and some individuals show no apparent avoidance.
    Captive bottlenose dolphins (Tursiops truncatus) and beluga whales 
exhibited changes in behavior when exposed to strong pulsed sounds 
similar in duration to those typically used in seismic surveys 
(Finneran et al., 2000, 2002, 2005). However, the animals tolerated 
high received levels of sound before exhibiting aversive behaviors.
    Results for porpoises depend on species. The limited available data 
suggest that harbor porpoises show stronger avoidance of seismic 
operations than do Dall's porpoises (Stone, 2003; MacLean and Koski, 
2005; Bain and Williams, 2006; Stone and Tasker, 2006). Dall's 
porpoises seem relatively tolerant of airgun operations (MacLean and 
Koski, 2005; Bain and Williams, 2006), although they too have been 
observed to avoid large arrays of operating airguns (Calambokidis and 
Osmek, 1998; Bain and Williams, 2006). This apparent difference in 
responsiveness of these two porpoise species is consistent with their 
relative responsiveness to boat traffic and some other acoustic sources 
(Richardson et al., 1995; Southall et al., 2007).
    Most studies of sperm whales exposed to airgun sounds indicate that 
the sperm whale shows considerable tolerance of airgun pulses (e.g., 
Stone, 2003; Moulton et al., 2005, 2006a; Stone and Tasker, 2006; Weir, 
2008). In most cases the whales do not show strong avoidance, and they 
continue to call. However, controlled exposure experiments in the Gulf 
of Mexico indicate that foraging behavior was altered upon exposure to 
airgun sound (Jochens et al., 2008; Miller et al., 2009; Tyack, 2009).
    There are almost no specific data on the behavioral reactions of 
beaked whales to seismic surveys. However, some northern bottlenose 
whales (Hyperoodon ampullatus) remained in the general area and 
continued to produce high-frequency clicks when exposed to sound pulses 
from distant seismic surveys (Gosselin and Lawson, 2004; Laurinolli and 
Cochrane, 2005; Simard et al., 2005). Most beaked whales tend to avoid 
approaching vessels of other types (e.g., Wursig et al., 1998). They 
may also dive for an extended period when approached by a vessel (e.g., 
Kasuya, 1986), although it is uncertain how much longer such dives may 
be as compared to dives by undisturbed beaked whales, which also are 
often quite long (Baird et al., 2006; Tyack et al., 2006). Based on a 
single observation, Aguilar-Soto et al. (2006) suggested that foraging 
efficiency of Cuvier's beaked whales may be reduced by close approach 
of vessels. In any event, it is likely that most beaked whales would 
also show strong avoidance of an approaching seismic vessel, although 
this has not been documented explicitly. In fact, Moulton and Holst 
(2010) reported 15 sightings of beaked whales during seismic studies in 
the Northwest Atlantic; seven of those sightings were made at times 
when at least one airgun was operating. There was little evidence to 
indicate that beaked whale behavior was affected by airgun operations; 
sighting rates and distances were similar during seismic and non-
seismic periods (Moulton and Holst, 2010).
    There are increasing indications that some beaked whales tend to 
strand when naval exercises involving mid-frequency sonar operation are 
ongoing nearby (e.g., Simmonds and Lopez-Jurado, 1991; Frantzis, 1998; 
NOAA and USN, 2001; Jepson et al., 2003; Hildebrand, 2005; Barlow and 
Gisiner, 2006; see also the ``Stranding and Mortality'' section in this 
notice). These strandings are apparently a disturbance response, 
although auditory or other injuries or other physiological effects may 
also be involved. Whether beaked whales would ever react similarly to 
seismic surveys is unknown. Seismic survey sounds are quite different 
from those of the sonar in operation during the above-cited incidents.
    Odontocete reactions to large arrays of airguns are variable and, 
at least for delphinids and Dall's porpoises, seem to be confined to a 
smaller radius than has been observed for the more responsive of some 
mysticetes. However, other data suggest that some odontocete species, 
including harbor porpoises, may be more responsive than might be 
expected given their poor low-frequency hearing. Reactions at longer 
distances may be particularly likely when sound propagation conditions 
are conducive to transmission of the higher frequency components of 
airgun sound to the animals' location (DeRuiter et al., 2006; Goold and 
Coates, 2006; Tyack et al., 2006; Potter et al., 2007).
    Pinnipeds--Pinnipeds are not likely to show a strong avoidance 
reaction to the airgun array. Visual monitoring from seismic vessels 
has shown only slight (if any) avoidance of airguns by pinnipeds, and 
only slight (if any) changes in behavior. In the Beaufort Sea, some 
ringed seals avoided an area of 100 m to (at most) a few hundred meters 
around seismic vessels, but many seals remained within 100 to 200 m 
(328 to 656 ft) of the trackline as the operating airgun array passed 
by (e.g., Harris et al., 2001; Moulton and Lawson, 2002; Miller et al., 
2005). Ringed seal sightings averaged somewhat farther away from the 
seismic vessel when the airguns

[[Page 58268]]

were operating than when they were not, but the difference was small 
(Moulton and Lawson, 2002). Similarly, in Puget Sound, sighting 
distances for harbor seals and California sea lions tended to be larger 
when airguns were operating (Calambokidis and Osmek, 1998). Previous 
telemetry work suggests that avoidance and other behavioral reactions 
may be stronger than evident to date from visual studies (Thompson et 
al., 1998).
    During seismic exploration off Nova Scotia, gray seals (Halichoerus 
grypus) exposed to noise from airguns and linear explosive charges did 
not react strongly (J. Parsons in Greene et al., 1985). Pinnipeds, in 
both water and air, sometimes tolerate strong noise pulses from non-
explosive and explosive scaring devices, especially if attracted to the 
area for feeding and reproduction (Mate and Harvey, 1987; Reeves et 
al., 1996). Thus, pinnipeds are expected to be rather tolerant of, or 
habituate to, repeated underwater sounds from distant seismic sources, 
at least when the animals are strongly attracted to the area.

Hearing Impairment and Other Physical Effects

    Exposure to high intensity sound for a sufficient duration may 
result in auditory effects such as a noise-induced threshold shift--an 
increase in the auditory threshold after exposure to noise (Finneran, 
Carder, Schlundt, and Ridgway, 2005). Factors that influence the amount 
of threshold shift include the amplitude, duration, frequency content, 
temporal pattern, and energy distribution of noise exposure. The 
magnitude of hearing threshold shift normally decreases over time 
following cessation of the noise exposure. The amount of threshold 
shift just after exposure is called the initial threshold shift. If the 
threshold shift eventually returns to zero (i.e., the threshold returns 
to the pre-exposure value), it is called temporary threshold shift 
(TTS) (Southall et al., 2007).
    Researchers have studied TTS in certain captive odontocetes and 
pinnipeds exposed to strong sounds (reviewed in Southall et al., 2007). 
However, there has been no specific documentation of TTS let alone 
permanent hearing damage, i.e., permanent threshold shift (PTS), in 
free-ranging marine mammals exposed to sequences of airgun pulses 
during realistic field conditions.
    Temporary Threshold Shift--TTS is the mildest form of hearing 
impairment that can occur during exposure to a strong sound (Kryter, 
1985). While experiencing TTS, the hearing threshold rises and a sound 
must be stronger in order to be heard. At least in terrestrial mammals, 
TTS can last from minutes or hours to (in cases of strong TTS) days. 
For sound exposures at or somewhat above the TTS threshold, hearing 
sensitivity in both terrestrial and marine mammals recovers rapidly 
after exposure to the noise ends. Few data on sound levels and 
durations necessary to elicit mild TTS have been obtained for marine 
mammals, and none of the published data concern TTS elicited by 
exposure to multiple pulses of sound. Available data on TTS in marine 
mammals are summarized in Southall et al. (2007). Table 1 (above) 
presents the estimated distances from the Langseth's airguns at which 
the received energy level (per pulse, flat-weighted) would be expected 
to be greater than or equal to 180 or 190 dB re 1 [micro]Pa (rms).
    To avoid the potential for injury, NMFS (1995, 2000) concluded that 
cetaceans and pinnipeds should not be exposed to pulsed underwater 
noise at received levels exceeding 180 and 190 dB re 1 [mu]Pa (rms), 
respectively. NMFS believes that to avoid the potential for Level A 
harassment, cetaceans and pinnipeds should not be exposed to pulsed 
underwater noise at received levels exceeding 180 and 190 dB re 1 
[mu]Pa (rms), respectively. The established 180 and 190 dB (rms) 
criteria are not considered to be the levels above which TTS might 
occur. Rather, they are the received levels above which, in the view of 
a panel of bioacoustics specialists convened by NMFS before TTS 
measurements for marine mammals started to become available, one could 
not be certain that there would be no injurious effects, auditory or 
otherwise, to marine mammals. NMFS also assumes that cetaceans and 
pinnipeds exposed to levels exceeding 160 dB re 1 [mu]Pa (rms) may 
experience Level B harassment.
    For toothed whales, researchers have derived TTS information for 
odontocetes from studies on the bottlenose dolphin and beluga. The 
experiments show that exposure to a single impulse at a received level 
of 207 kPa (or 30 psi, p-p), which is equivalent to 228 dB re 1 Pa (p-
p), resulted in a 7 and 6 dB TTS in the beluga whale at 0.4 and 30 kHz, 
respectively. Thresholds returned to within 2 dB of the pre-exposure 
level within 4 minutes of the exposure (Finneran et al., 2002). For the 
one harbor porpoise tested, the received level of airgun sound that 
elicited onset of TTS was lower (Lucke et al., 2009). If these results 
from a single animal are representative, it is inappropriate to assume 
that onset of TTS occurs at similar received levels in all odontocetes 
(cf. Southall et al., 2007). Some cetaceans apparently can incur TTS at 
considerably lower sound exposures than are necessary to elicit TTS in 
the beluga or bottlenose dolphin.
    For baleen whales, there are no data, direct or indirect, on levels 
or properties of sound that are required to induce TTS. The frequencies 
to which baleen whales are most sensitive are assumed to be lower than 
those to which odontocetes are most sensitive, and natural background 
noise levels at those low frequencies tend to be higher. As a result, 
auditory thresholds of baleen whales within their frequency band of 
best hearing are believed to be higher (less sensitive) than are those 
of odontocetes at their best frequencies (Clark and Ellison, 2004). 
From this, it is suspected that received levels causing TTS onset may 
also be higher in baleen whales than those of odontocetes (Southall et 
al., 2007).
    In pinnipeds, researchers have not measured TTS thresholds 
associated with exposure to brief pulses (single or multiple) of 
underwater sound. Initial evidence from more prolonged (non-pulse) 
exposures suggested that some pinnipeds (harbor seals in particular) 
incur TTS at somewhat lower received levels than do small odontocetes 
exposed for similar durations (Kastak et al., 1999, 2005; Ketten et 
al., 2001). The TTS threshold for pulsed sounds has been indirectly 
estimated as being an SEL of approximately 171 dB re 1 
[micro]Pa\2\[middot]s (Southall et al., 2007) which would be equivalent 
to a single pulse with a received level of approximately 181 to 186 dB 
re 1 [micro]Pa (rms), or a series of pulses for which the highest rms 
values are a few dB lower. Corresponding values for California sea 
lions and northern elephant seals are likely to be higher (Kastak et 
al., 2005).
    Permanent Threshold Shift--When PTS occurs, there is physical 
damage to the sound receptors in the ear. In severe cases, there can be 
total or partial deafness, whereas 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 of airgun 
sound can cause PTS in any marine mammal, even with large arrays of 
airguns. However, given the possibility that mammals close to an airgun 
array might incur at least mild TTS, there has been further speculation 
about the possibility that some individuals occurring very close to 
airguns might incur PTS (e.g., Richardson et al., 1995, p. 372ff; 
Gedamke et al., 2008). Single or occasional occurrences of mild TTS are 
not indicative of permanent auditory

[[Page 58269]]

damage, but repeated or (in some cases) single exposures to a level 
well above that causing TTS onset might elicit PTS.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals, but are assumed to be similar to those in humans and 
other terrestrial mammals (Southall et al., 2007). PTS might occur at a 
received sound level at least several dBs above that inducing mild TTS 
if the animal were exposed to strong sound pulses with rapid rise 
times. Based on data from terrestrial mammals, a precautionary 
assumption is that the PTS threshold for impulse sounds (such as airgun 
pulses as received close to the source) is at least 6 dB higher than 
the TTS threshold on a peak-pressure basis, and probably greater than 6 
dB (Southall et al., 2007).
    Given the higher level of sound necessary to cause PTS as compared 
with TTS, it is considerably less likely that PTS would occur. Baleen 
whales generally avoid the immediate area around operating seismic 
vessels, as do some other marine mammals. Some pinnipeds show avoidance 
reactions to airguns, but their avoidance reactions are generally not 
as strong or consistent as those of cetaceans, and occasionally they 
seem to be attracted to operating seismic vessels (NMFS, 2010).
    Stranding and Mortality--When a living or dead marine mammal swims 
or floats onto shore and becomes ``beached'' or incapable of returning 
to sea, the event is termed a ``stranding'' (Geraci et al., 1999; 
Perrin and Geraci, 2002; Geraci and Lounsbury, 2005; NMFS, 2007). The 
legal definition for a stranding under the MMPA is that ``(A) a marine 
mammal is dead and is (i) on a beach or shore of the United States; or 
(ii) in waters under the jurisdiction of the United States (including 
any navigable waters); or (B) a marine mammal is alive and is (i) on a 
beach or shore of the United States and is unable to return to the 
water; (ii) on a beach or shore of the United States and, although able 
to return to the water is in need of apparent medical attention; or 
(iii) in the waters under the jurisdiction of the United States 
(including any navigable waters), but is unable to return to its 
natural habitat under its own power or without assistance.''
    Marine mammals are known to strand for a variety of reasons, such 
as infectious agents, biotoxicosis, starvation, fishery interaction, 
ship strike, unusual oceanographic or weather events, sound exposure, 
or combinations of these stressors sustained concurrently or in series. 
However, the cause or causes of most strandings are unknown (Geraci et 
al., 1976; Eaton, 1979; Odell et al., 1980; Best, 1982). Numerous 
studies suggest that the physiology, behavior, habitat relationships, 
age, or condition of cetaceans may cause them to strand or might pre-
dispose them to strand when exposed to another phenomenon. These 
suggestions are consistent with the conclusions of numerous other 
studies that have demonstrated that combinations of dissimilar 
stressors commonly combine to kill an animal or dramatically reduce its 
fitness, even though one exposure without the other does not produce 
the same result (Chroussos, 2000; Creel, 2005; DeVries et al., 2003; 
Fair and Becker, 2000; Foley et al., 2001; Moberg, 2000; Relyea, 2005a, 
2005b; Romero, 2004; Sih et al., 2004).
    Strandings Associated with Military Active Sonar--Several sources 
have published lists of mass stranding events of cetaceans in an 
attempt to identify relationships between those stranding events and 
military active sonar (Hildebrand, 2004; IWC, 2005; Taylor et al., 
2004). For example, based on a review of stranding records between 1960 
and 1995, the International Whaling Commission (2005) identified ten 
mass stranding events and concluded that, out of eight stranding events 
reported from the mid-1980s to the summer of 2003, seven had been 
coincident with the use of mid-frequency active sonar and most involved 
beaked whales.
    Over the past 12 years, there have been five stranding events 
coincident with military mid-frequency active sonar use in which 
exposure to sonar is believed to have been a contributing factor to 
strandings: Greece (1996); the Bahamas (2000); Madeir (2000); Canary 
Islands (2002); and Spain (2006). Refer to Cox et al. (2006) for a 
summary of common features shared by the strandings events in Greece 
(1996), Bahamas (2000), Madeira (2000), and Canary Islands (2002); and 
Fernandez et al., (2005) for an additional summary of the Canary 
Islands 2002 stranding event.
    Potential for Stranding from Seismic Surveys--Marine mammals close 
to underwater detonations of high explosives can be killed or severely 
injured, and the auditory organs are especially susceptible to injury 
(Ketten et al., 1993; Ketten, 1995). However, explosives are no longer 
used in marine waters for commercial seismic surveys or (with rare 
exceptions) for seismic research. These methods have been replaced 
entirely by airguns or related non-explosive pulse generators. Airgun 
pulses are less energetic and have slower rise times, and there is no 
specific evidence that they can cause serious injury, death, or 
stranding even in the case of large airgun arrays. However, the 
association of strandings of beaked whales with naval exercises 
involving mid-frequency active sonar (non-pulse sound) and, in one 
case, the co-occurrence of an L-DEO seismic survey (Malakoff, 2002; Cox 
et al., 2006), has raised the possibility that beaked whales exposed to 
strong ``pulsed'' sounds could also be susceptible to injury and/or 
behavioral reactions that can lead to stranding (e.g., Hildebrand, 
2005; Southall et al., 2007).
    Specific sound-related processes that lead to strandings and 
mortality are not well documented, but may include:
    (1) Swimming in avoidance of a sound into shallow water;
    (2) A change in behavior (such as a change in diving behavior) that 
might contribute to tissue damage, gas bubble formation, hypoxia, 
cardiac arrhythmia, hypertensive hemorrhage or other forms of trauma;
    (3) A physiological change such as a vestibular response leading to 
a behavioral change or stress-induced hemorrhagic diathesis, leading in 
turn to tissue damage; and
    (4) Tissue damage directly from sound exposure, such as through 
acoustically-mediated bubble formation and growth or acoustic resonance 
of tissues.

Some of these mechanisms are unlikely to apply in the case of impulse 
sounds. However, there are indications that gas-bubble disease 
(analogous to ``the bends''), induced in supersaturated tissue by a 
behavioral response to acoustic exposure, could be a pathologic 
mechanism for the strandings and mortality of some deep-diving 
cetaceans exposed to sonar. The evidence for this remains 
circumstantial and associated with exposure to naval mid-frequency 
sonar, not seismic surveys (Cox et al., 2006; Southall et al., 2007).
    Seismic pulses and mid-frequency sonar signals are quite different, 
and some mechanisms by which sonar sounds have been hypothesized to 
affect beaked whales are unlikely to apply to airgun pulses. Sounds 
produced by airgun arrays are broadband impulses with most of the 
energy below one kHz. Typical military mid-frequency sonar emits non-
impulse sounds at frequencies of 2 to 10 kHz, generally with a 
relatively narrow bandwidth at any one time. A further difference 
between seismic surveys and naval exercises is that naval exercises can 
involve sound sources on more than one vessel. Thus, it is not 
appropriate to expect that the same to marine mammals will result from 
military sonar

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and seismic surveys. However, evidence that sonar signals can, in 
special circumstances, lead (at least indirectly) to physical damage 
and mortality (e.g., Balcomb and Claridge, 2001; NOAA and USN, 2001; 
Jepson et al., 2003; Fern[aacute]ndez et al., 2004, 2005; Hildebrand 
2005; Cox et al., 2006) suggests that caution is warranted when dealing 
with exposure of marine mammals to any high-intensity sound.
    There is no conclusive evidence of cetacean strandings or deaths at 
sea as a result of exposure to seismic surveys, but a few cases of 
strandings in the general area where a seismic survey was ongoing have 
led to speculation concerning a possible link between seismic surveys 
and strandings. Suggestions that there was a link between seismic 
surveys and strandings of humpback whales in Brazil (Engel et al., 
2004) were not well founded (IAGC, 2004; IWC, 2007). In September, 
2002, there was a stranding of two Cuvier's beaked whales in the Gulf 
of California, Mexico, when the L-DEO vessel R/V Maurice Ewing was 
operating a 20 airgun (8,490 in\3\) array in the general area. The link 
between the stranding and the seismic surveys was inconclusive and not 
based on any physical evidence (Hogarth, 2002; Yoder, 2002). 
Nonetheless, the Gulf of California incident plus the beaked whale 
strandings near naval exercises involving use of mid-frequency sonar 
suggests a need for caution in conducting seismic surveys in areas 
occupied by beaked whales until more is known about effects of seismic 
surveys on those species (Hildebrand, 2005). No injuries of beaked 
whales are anticipated during the proposed study because of:
    (1) The high likelihood that any beaked whales nearby would avoid 
the approaching vessel before being exposed to high sound levels, and
    (2) Differences between the sound sources operated by L-DEO and 
those involved in the naval exercises associated with strandings.
    Non-auditory Physiological Effects--Non-auditory physiological 
effects or injuries that theoretically might occur in marine mammals 
exposed to strong underwater sound include stress, neurological 
effects, bubble formation, resonance, and other types of organ or 
tissue damage (Cox et al., 2006; Southall et al., 2007). Studies 
examining such effects are limited. However, resonance effects (Gentry, 
2002) and direct noise-induced bubble formations (Crum et al., 2005) 
are implausible in the case of exposure to an impulsive broadband 
source like an airgun array. If seismic surveys disrupt diving patterns 
of deep-diving species, this might perhaps result in bubble formation 
and a form of the bends, as speculated to occur in beaked whales 
exposed to sonar. However, there is no specific evidence of this upon 
exposure to airgun pulses.
    In general, very little is known about the potential for seismic 
survey sounds (or other types of strong underwater sounds) to cause 
non-auditory physical effects in marine mammals. Such effects, if they 
occur at all, would presumably be limited to short distances and to 
activities that extend over a prolonged period. The available data do 
not allow identification of a specific exposure level above which non-
auditory effects can be expected (Southall et al., 2007), or any 
meaningful quantitative predictions of the numbers (if any) of marine 
mammals that might be affected in those ways. Marine mammals that show 
behavioral avoidance of seismic vessels, including most baleen whales, 
some odontocetes, and some pinnipeds, are especially unlikely to incur 
non-auditory physical effects.

Potential Effects of Other Acoustic Devices

Multibeam Echosounder
    L-DEO and PG&E will operate the Kongsberg EM 122 multibeam 
echosounder from the source vessel during the planned study. Sounds 
from the multibeam echosounder are very short pulses, occurring for 2 
to 15 ms once every 5 to 20 s, depending on water depth. Most of the 
energy in the sound pulses emitted by this multibeam echosounder is at 
frequencies near 12 kHz, and the maximum source level is 242 dB re 1 
[mu]Pa (rms). The beam is narrow (1 to 2[deg]) in fore-aft extent and 
wide (150[deg]) in the cross-track extent. Each ping consists of eight 
(in water greater than 1,000 m deep) or four (in water less than 1,000 
m deep) successive fan-shaped transmissions (segments) at different 
cross-track angles. Any given mammal at depth near the trackline would 
be in the main beam for only one or two of the nine segments. Also, 
marine mammals that encounter the Kongsberg EM 122 are unlikely to be 
subjected to repeated pulses because of the narrow fore-aft width of 
the beam and will receive only limited amounts of pulse energy because 
of the short pulses. Animals close to the ship (where the beam is 
narrowest) are especially unlikely to be ensonified for more than one 2 
to 15 ms pulse (or two pulses if in the overlap area). Similarly, 
Kremser et al. (2005) noted that the probability of a cetacean swimming 
through the area of exposure when a multibeam echosounder emits a pulse 
is small. The animal would have to pass the transducer at close range 
and be swimming at speeds similar to the vessel in order to receive the 
multiple pulses that might result in sufficient exposure to cause TTS.
    Navy sonars that have been linked to avoidance reactions and 
stranding of cetaceans: (1) Generally have longer pulse duration than 
the Kongsberg EM 122; and (2) are often directed close to horizontally 
versus more downward for the multibeam echosounder. The area of 
possible influence of the multibeam echosounder is much smaller--a 
narrow band below the source vessel. Also, the duration of exposure for 
a given marine mammal can be much longer for naval sonar. During L-DEO 
and PG&E's operations, the individual pulses will be very short, and a 
given mammal would not receive many of the downward-directed pulses as 
the vessel passes by. Possible effects of a multibeam echosounder on 
marine mammals are described below.
    Masking--Marine mammal communications will not be masked 
appreciably by the multibeam echosounder signals given the low duty 
cycle of the echosounder and the brief period when an individual mammal 
is likely to be within its beam. Furthermore, in the case of baleen 
whales, the multibeam echosounder signals (12 kHz) do not overlap with 
the predominant frequencies in the calls, which would avoid any 
significant masking.
    Behavioral Responses--Behavioral reactions of free-ranging marine 
mammals to sonars, echosounders, and other sound sources appear to vary 
by species and circumstance. Observed reactions have included silencing 
and dispersal by sperm whales (Watkins et al., 1985), increased 
vocalizations and no dispersal by pilot whales (Rendell and Gordon, 
1999), and the previously-mentioned beachings by beaked whales. During 
exposure to a 21 to 25 kHz ``whale-finding'' sonar with a source level 
of 215 dB re 1 [micro]Pa, gray whales reacted by orienting slightly 
away from the source and being deflected from their course by 
approximately 200 m (656.2 ft) (Frankel, 2005). When a 38 kHz 
echosounder and a 150 kHz acoustic Doppler current profiler were 
transmitting during studies in the Eastern Tropical Pacific, baleen 
whales showed no significant responses, while spotted and spinner 
dolphins were detected slightly more often and beaked whales less often 
during visual surveys (Gerrodette and Pettis, 2005).
    Captive bottlenose dolphins and a beluga whale exhibited changes in

[[Page 58271]]

behavior when exposed to 1 s tonal signals at frequencies similar to 
those that will be emitted by the multibeam echosounder used by L-DEO 
and PG&E, and to shorter broadband pulsed signals. Behavioral changes 
typically involved what appeared to be deliberate attempts to avoid the 
sound exposure (Schlundt et al., 2000; Finneran et al., 2002; Finneran 
and Schlundt, 2004). The relevance of those data to free-ranging 
odontocetes is uncertain, and in any case, the test sounds were quite 
different in duration as compared with those from a multibeam 
echosounder.
    Very few data are available on the reactions of pinnipeds to 
echosounder sounds at frequencies similar to those used during seismic 
operations. Hastie and Janik (2007) conducted a series of behavioral 
response tests on two captive gray seals to determine their reactions 
to underwater operation of a 375 kHz multibeam imaging echosounder that 
included significant signal components down to 6 kHz. Results indicated 
that the two seals reacted to the signal by significantly increasing 
their dive durations. Because of the likely brevity of exposure to the 
multibeam echosounder sounds, pinniped reactions are expected to be 
limited to startle or otherwise brief responses of no lasting 
consequences to the animals.
    Hearing Impairment and Other Physical Effects--Given recent 
stranding events that have been associated with the operation of naval 
sonar, there is concern that mid-frequency sonar sounds can cause 
serious impacts to marine mammals (see above). However, the multibeam 
echosounder proposed for use by L-DEO and PG&E is quite different than 
sonar used for Navy operations. Pulse duration of the multibeam 
echosounder is very short relative to the naval sonar. Also, at any 
given location, an individual marine mammal would be in the beam of the 
multibeam echosounder for much less time given the generally downward 
orientation of the beam and its narrow fore-aft beamwidth; Navy sonar 
often uses near-horizontally-directed sound. Those factors would all 
reduce the sound energy received from the multibeam echosounder rather 
drastically relative to that from naval sonar.
    NMFS believes that the brief exposure of marine mammals to one 
pulse, or small numbers of signals, from the multibeam echosounder is 
not likely to result in the harassment of marine mammals.
Sub-Bottom Profiler
    L-DEO and PG&E will also operate a sub-bottom profiler from the 
source vessel during the proposed survey. Sounds from the sub-bottom 
profiler are very short pulses, occurring for 1 to 4 ms once every 
second. Most of the energy in the sound pulses emitted by the sub-
bottom profiler is at 3.5 kHz, and the beam is directed downward. The 
sub-bottom profiler on the Langseth has a maximum source level of 204 
dB re 1 [micro]Pa. Kremser et al. (2005) noted that the probability of 
a cetacean swimming through the area of exposure when a bottom profiler 
emits a pulse is small--even for a sub-bottom profiler more powerful 
than that on the Langseth. If the animal was in the area, it would have 
to pass the transducer at close range in order to be subjected to sound 
levels that could cause TTS.
    Masking--Marine mammal communications will not be masked 
appreciably by the sub-bottom profiler signals given the directionality 
of the signal and the brief period when an individual mammal is likely 
to be within its beam. Furthermore, in the case of most baleen whales, 
the sub-bottom profiler signals do not overlap with the predominant 
frequencies in the calls, which would avoid significant masking.
    Behavioral Responses--Marine mammal behavioral reactions to other 
pulsed sound sources are discussed above, and responses to the sub-
bottom profiler are likely to be similar to those for other pulsed 
sources if received at the same levels. However, the pulsed signals 
from the sub-bottom profiler are considerably weaker than those from 
the multibeam echosounder. Therefore, behavioral responses are not 
expected unless marine mammals are very close to the source.
    Hearing Impairment and Other Physical Effects--It is unlikely that 
the sub-bottom profiler produces pulse levels strong enough to cause 
hearing impairment or other physical injuries even in an animal that is 
(briefly) in a position near the source. The sub-bottom profiler is 
usually operated simultaneously with other higher-power acoustic 
sources, including airguns. Many marine mammals will move away in 
response to the approaching higher-power sources or the vessel itself 
before the mammals would be close enough for there to be any 
possibility of effects from the less intense sounds from the sub-bottom 
profiler.
Vessel Movement and Collisions
    Vessel movement in the vicinity of marine mammals has the potential 
to result in either a behavioral response or a direct physical 
interaction. Both scenarios are discussed below in this section.
    Behavioral Responses to Vessel Movement--There are limited data 
concerning marine mammal behavioral responses to vessel traffic and 
vessel noise, and a lack of consensus among scientists with respect to 
what these responses mean or whether they result in short-term or long-
term adverse effects. In those cases where there is a busy shipping 
lane or where there is a large amount of vessel traffic, marine mammals 
(especially low frequency specialists) may experience acoustic masking 
(Hildebrand, 2005) if they are present in the area (e.g., killer whales 
in Puget Sound; Foote et al., 2004; Holt et al., 2008). In cases where 
vessels actively approach marine mammals (e.g., whale watching or 
dolphin watching boats), scientists have documented that animals 
exhibit altered behavior such as increased swimming speed, erratic 
movement, and active avoidance behavior (Bursk, 1983; Acevedo, 1991; 
Baker and MacGibbon, 1991; Trites and Bain, 2000; Williams et al., 
2002; Constantine et al., 2003), reduced blow interval (Ritcher et al., 
2003), disruption of normal social behaviors (Lusseau, 2003, 2006), and 
the shift of behavioral activities which may increase energetic costs 
(Constantine et al., 2003, 2004). A detailed review of marine mammal 
reactions to ships and boats is available in Richardson et al., (1995). 
For each of the marine mammal taxonomy groups, Richardson et al., 
(1995) provides the following assessment regarding reactions to vessel 
traffic:
    Toothed whales--``In summary, toothed whales sometimes show no 
avoidance reaction to vessels, or even approach them. However, 
avoidance can occur, especially in response to vessels of types used to 
chase or hunt the animals. This may cause temporary displacement, but 
we know of no clear evidence that toothed whales have abandoned 
significant parts of their range because of vessel traffic.''
    Baleen whales--``When baleen whales receive low-level sounds from 
distant or stationary vessels, the sounds often seem to be ignored. 
Some whales approach the sources of these sounds. When vessels approach 
whales slowly and non-aggressively, whales often exhibit slow and 
inconspicuous avoidance maneuvers. In response to strong or rapidly 
changing vessel noise, baleen whales often interrupt their normal 
behavior and swim rapidly away. Avoidance is especially strong when a 
boat heads directly toward the whale.''
    Behavioral responses to stimuli are complex and influenced to 
varying degrees by a number of factors, such as

[[Page 58272]]

species, behavioral contexts, geographical regions, source 
characteristics (moving or stationary, speed, direction, etc.), prior 
experience of the animal and physical status of the animal. For 
example, studies have shown that beluga whales' reaction varied when 
exposed to vessel noise and traffic. In some cases, beluga whales 
exhibited rapid swimming from ice-breaking vessels up to 80 km (43.2 
nmi) away, and showed changes in surfacing, breathing, diving, and 
group composition in the Canadian high Arctic where vessel traffic is 
rare (Finley et al., 1990). In other cases, beluga whales were more 
tolerant of vessels, but responded differentially to certain vessels 
and operating characteristics by reducing their calling rates 
(especially older animals) in the St. Lawrence River where vessel 
traffic is common (Blane and Jaakson, 1994). In Bristol Bay, Alaska, 
beluga whales continued to feed when surrounded by fishing vessels and 
resisted dispersal even when purposefully harassed (Fish and Vania, 
1971).
    In reviewing more than 25 years of whale observation data, Watkins 
(1986) concluded that whale reactions to vessel traffic were ``modified 
by their previous experience and current activity: Habituation often 
occurred rapidly, attention to other stimuli or preoccupation with 
other activities sometimes overcame their interest or wariness of 
stimuli.'' Watkins noticed that over the years of exposure to ships in 
the Cape Cod area, minke whales changed from frequent positive interest 
(e.g., approaching vessels) to generally uninterested reactions; fin 
whales changed from mostly negative (e.g., avoidance) to uninterested 
reactions; fin whales changed from mostly negative (e.g., avoidance) to 
uninterested reactions; right whales apparently continued the same 
variety of responses (negative, uninterested, and positive responses) 
with little change; and humpbacks dramatically changed from mixed 
responses that were often negative to reactions that were often 
strongly positive. Watkins (1986) summarized that ``whales near shore, 
even in regions with low vessel traffic, generally have become less 
wary of boats and their noises, and they have appeared to be less 
easily disturbed than previously. In particular locations with intense 
shipping and repeated approaches by boats (such as the whale-watching 
areas of Stellwagen Bank), more and more whales had positive reactions 
to familiar vessels, and they also occasionally approached other boats 
and yachts in the same ways.''
    Although the radiated sound from the Langseth and support vessels 
will be audible to marine mammals over a large distance, it is unlikely 
that marine mammals will respond behaviorally (in a manner that NMFS 
would consider harassment under the MMPA) to low-level distant shipping 
noise as the animals in the area are likely to be habituated to such 
noises (Nowacek et al., 2004). In light of these facts, NMFS does not 
expect the Langseth's movements to result in Level B harassment.
    Vessel Strike--Ship strikes of cetaceans can cause major wounds, 
which may lead to the death of the animal. An animal at the surface 
could be struck directly by a vessel, a surfacing animal could hit the 
bottom of a vessel, or an animal just below the surface could be cut by 
a vessel's propeller. The severity of injuries typically depends on the 
size and speed of the vessel (Knowlton and Kraus, 2001; Laist et al., 
2001; Vanderlaan and Taggart, 2007).
    The most vulnerable marine mammals are those that spend extended 
periods of time at the surface in order to restore oxygen levels within 
their tissues after deep dives (e.g., the sperm whale). In addition, 
some baleen whales, such as the North Atlantic right whale, seem 
generally unresponsive to vessel sound, making them more susceptible to 
vessel collisions (Nowacek et al., 2004). These species are primarily 
large, slow moving whales. Smaller marine mammals (e.g., bottlenose 
dolphin) move quickly through the water column and are often seen 
riding the bow wave of large ships. Marine mammal responses to vessels 
may include avoidance and changes in dive pattern (NRC, 2003).
    An examination of all known ship strikes from all shipping sources 
(civilian and military) indicates vessel speed is a principal factor in 
whether a vessel strike results in death (Knowlton and Kraus, 2001; 
Laist et al., 2001; Jensen and Silber, 2003; Vanderlaan and Taggart, 
2007). In assessing records in which vessel speed was known, Laist et 
al. (2001) found a direct relationship between the occurrence of a 
whale strike and the speed of the vessel involved in the collision. The 
authors concluded that most deaths occurred when a vessel was traveling 
in excess of 13 kts (24.1 km/hr, 14.9 mph).
    L-DEO and PG&E's proposed operation of one source vessel and 
support vessels for the proposed survey is relatively small in scale 
compared to the number of commercial ships transiting at higher speeds 
in the same areas on an annual basis. The probability of vessel and 
marine mammal interactions occurring during the proposed survey is 
unlikely due to the Langseth's and support vessels slow operational 
speed, which is typically 4.6 kts (8.5 km/hr, 5.3 mph). Outside of 
seismic operations, the Langseth's cruising speed would be 
approximately 10 kts (18.5 km/hr, 11.5 mph), which is generally below 
the speed at which studies have noted reported increases of marine 
mammal injury or death (Laist et al., 2001).
    As a final point, the Langseth has a number of other advantages for 
avoiding ship strikes as compared to most commercial merchant vessels, 
including the following: the Langseth's bridge offers good visibility 
to visually monitor for marine mammal presence; PSOs posted during 
operations scan the ocean for marine mammals and must report visual 
alerts of marine mammal presence to crew; and the PSOs receive 
extensive training that covers the fundamentals of visual observing for 
marine mammals and information about marine mammals and their 
identification at sea.
Entanglement
    Entanglement can occur if wildlife becomes immobilized in survey 
lines, cables, nets, or other equipment that is moving through the 
water column. The proposed seismic survey would require towing 
approximately 6.4 km\2\ (1.9 nmi\2\) of equipment and cables. This 
large of an array carries the risk of entanglement for marine mammals. 
Wildlife, especially slow moving individuals, such as large whales, 
have a low probability of becoming entangled due to slow speed of the 
survey vessel and onboard monitoring efforts. The NSF has no recorded 
cases of entanglement of marine mammals during any of their 160,934 km 
(86,897.4 nmi) of seismic surveys. In May, 2011, there was one recorded 
entanglement of an olive ridley sea turtle (Lepidochelys olivacea) in 
the Langseth's barovanes after the conclusion of a seismic survey off 
Costa Rica. There have cases of baleen whales, mostly gray whales 
(Heyning, 1990), becoming entangled in fishing lines. The probability 
for entanglement of marine mammals is considered not significant 
because of the vessel speed and the monitoring efforts onboard the 
survey vessel.
    The potential effects to marine mammals described in this section 
of the document do not take into consideration the proposed monitoring 
and mitigation measures described later in this document (see the 
``Proposed Mitigation'' and ``Proposed Monitoring and Reporting'' 
sections) which, as

[[Page 58273]]

noted are designed to effect the least practicable impact on affected 
marine mammal species and stocks.

Anticipated Effects on Marine Mammal Habitat

    The proposed seismic survey is not anticipated to have any 
permanent impact on habitats used by the marine mammals in the proposed 
survey area, including the food sources they use (i.e. fish and 
invertebrates). Additionally, no physical damage to any habitat is 
anticipated as a result of conducting the proposed seismic survey. 
While it is anticipated that the specified activity may result in 
marine mammals avoiding certain areas due to temporary ensonification, 
this impact to habitat is temporary and was considered in further 
detail earlier in this document, as behavioral modification. The main 
impact associated with the proposed activity will be temporarily 
elevated noise levels and the associated direct effects on marine 
mammals in any particular area of the approximately 740.5 km\2\ 
proposed project area, previously discussed in this notice. The next 
section discusses the potential impacts of anthropogenic sound sources 
on common marine mammal prey in the proposed survey area (i.e., fish 
and invertebrates).

Anticipated Effects on Fish

    One reason for the adoption of airguns as the standard energy 
source for marine seismic surveys is that, unlike explosives, they have 
not been associated with large-scale fish kills. However, existing 
information on the impacts of seismic surveys on marine fish and 
invertebrate populations is limited. There are three types of potential 
effects of exposure to seismic surveys: (1) pathological, (2) 
physiological, and (3) behavioral. Pathological effects involve lethal 
and temporary or permanent sub-lethal injury. Physiological effects 
involve temporary and permanent primary and secondary stress responses, 
such as changes in levels of enzymes and proteins. Behavioral effects 
refer to temporary and (if they occur) permanent changes in exhibited 
behavior (e.g., startle and avoidance behavior). The three categories 
are interrelated in complex ways. For example, it is possible that 
certain physiological and behavioral changes could potentially lead to 
an ultimate pathological effect on individuals (i.e., mortality).
    The specific received sound levels at which permanent adverse 
effects to fish potentially could occur are little studied and largely 
unknown. Furthermore, the available information on the impacts of 
seismic surveys on marine fish is from studies of individuals or 
portions of a population; there have been no studies at the population 
scale. The studies of individual fish have often been on caged fish 
that were exposed to airgun pulses in situations not representative of 
an actual seismic survey. Thus, available information provides limited 
insight on possible real-world effects at the ocean or population 
scale. This makes drawing conclusions about impacts on fish problematic 
because, ultimately, the most important issues concern effects on 
marine fish populations, their viability, and their availability to 
fisheries.
    Hastings and Popper (2005), Popper (2009), and Popper and Hastings 
(2009a,b) provided recent critical reviews of the known effects of 
sound on fish. The following sections provide a general synopsis of the 
available information on the effects of exposure to seismic and other 
anthropogenic sound as relevant to fish. The information comprises 
results from scientific studies of varying degrees of rigor plus some 
anecdotal information. Some of the data sources may have serious 
shortcomings in methods, analysis, interpretation, and reproducibility 
that must be considered when interpreting their results (see Hastings 
and Popper, 2005). Potential adverse effects of the program's sound 
sources on marine fish are noted.
    Pathological Effects--The potential for pathological damage to 
hearing structures in fish depends on the energy level of the received 
sound and the physiology and hearing capability of the species in 
question. For a given sound to result in hearing loss, the sound must 
exceed, by some substantial amount, the hearing threshold of the fish 
for that sound (Popper, 2005). The consequences of temporary or 
permanent hearing loss in individual fish on a fish population are 
unknown; however, they likely depend on the number of individuals 
affected and whether critical behaviors involving sound (e.g., predator 
avoidance, prey capture, orientation and navigation, reproduction, 
etc.) are adversely affected.
    Little is known about the mechanisms and characteristics of damage 
to fish that may be inflicted by exposure to seismic survey sounds. Few 
data have been presented in the peer-reviewed scientific literature. As 
far as L-DEO, PG&E, and NMFS know, there are only two papers with 
proper experimental methods, controls, and careful pathological 
investigation implicating sounds produced by actual seismic survey 
airguns in causing adverse anatomical effects. One such study indicated 
anatomical damage, and the second indicated TTS in fish hearing. The 
anatomical case is McCauley et al. (2003), who found that exposure to 
airgun sound caused observable anatomical damage to the auditory 
maculae of pink snapper (Pagrus auratus). This damage in the ears had 
not been repaired in fish sacrificed and examined almost two months 
after exposure. On the other hand, Popper et al. (2005) documented only 
TTS (as determined by auditory brainstem response) in two of three fish 
species from the Mackenzie River Delta. This study found that broad 
whitefish (Coregonus nasus) exposed to five airgun shots were not 
significantly different from those of controls. During both studies, 
the repetitive exposure to sound was greater than would have occurred 
during a typical seismic survey. However, the substantial low-frequency 
energy produced by the airguns (less than 400 Hz in the study by 
McCauley et al. [2003] and less than approximately 200 Hz in Popper et 
al. [2005]) likely did not propagate to the fish because the water in 
the study areas was very shallow (approximately nine m in the former 
case and less than two m in the latter). Water depth sets a lower limit 
on the lowest sound frequency that will propagate (the ``cutoff 
frequency'') at about one-quarter wavelength (Urick, 1983; Rogers and 
Cox, 1988).
    Wardle et al. (2001) suggested that in water, acute injury and 
death of organisms exposed to seismic energy depends primarily on two 
features of the sound source: (1) the received peak pressure, and (2) 
the time required for the pressure to rise and decay. Generally, as 
received pressure increases, the period for the pressure to rise and 
decay decreases, and the chance of acute pathological effects 
increases. According to Buchanan et al. (2004), for the types of 
seismic airguns and arrays involved with the proposed program, the 
pathological (mortality) zone for fish would be expected to be within a 
few meters of the seismic source. Numerous other studies provide 
examples of no fish mortality upon exposure to seismic sources (Falk 
and Lawrence, 1973; Holliday et al., 1987; La Bella et al., 1996; 
Santulli et al., 1999; McCauley et al., 2000a,b, 2003; Bjarti, 2002; 
Thomsen, 2002; Hassel et al., 2003; Popper et al., 2005; Boeger et al., 
2006).
    An experiment of the effects of a single 700 in\3\ airgun was 
conducted in Lake Meade, Nevada (USGS, 1999). The data were used in an 
Environmental Assessment of the effects of a marine reflection survey 
of the Lake Meade

[[Page 58274]]

fault system by the National Park Service (Paulson et al., 1993, in 
USGS, 1999). The airgun was suspended 3.5 m (11.5 ft) above a school of 
threadfin shad in Lake Meade and was fired three successive times at a 
30 second interval. Neither surface inspection nor diver observations 
of the water column and bottom found any dead fish.
    For a proposed seismic survey in Southern California, USGS (1999) 
conducted a review of the literature on the effects of airguns on fish 
and fisheries. They reported a 1991 study of the Bay Area Fault system 
from the continental shelf to the Sacramento River, using a 10 airgun 
(5,828 in\3\) array. Brezzina and Associates were hired by USGS to 
monitor the effects of the surveys, and concluded that airgun 
operations were not responsible for the death of any of the fish 
carcasses observed, and the airgun profiling did not appear to alter 
the feeding behavior of sea lions, seals, or pelicans observed feeding 
during the seismic surveys.
    Some studies have reported, some equivocally, that mortality of 
fish, fish eggs, or larvae can occur close to seismic sources 
(Kostyuchenko, 1973; Dalen and Knutsen, 1986; Booman et al., 1996; 
Dalen et al., 1996). Some of the reports claimed seismic effects from 
treatments quite different from actual seismic survey sounds or even 
reasonable surrogates. However, Payne et al. (2009) reported no 
statistical differences in mortality/morbidity between control and 
exposed groups of capelin eggs or monkfish larvae. Saetre and Ona 
(1996) applied a `worst-case scenario' mathematical model to 
investigate the effects of seismic energy on fish eggs and larvae. They 
concluded that mortality rates caused by exposure to seismic surveys 
are so low, as compared to natural mortality rates, that the impact of 
seismic surveying on recruitment to a fish stock must be regarded as 
insignificant.
    Physiological Effects--Physiological effects refer to cellular and/
or biochemical responses of fish to acoustic stress. Such stress 
potentially could affect fish populations by increasing mortality or 
reducing reproductive success. Primary and secondary stress responses 
of fish after exposure to seismic survey sound appear to be temporary 
in all studies done to date (Sverdrup et al., 1994; Santulli et al., 
1999; McCauley et al., 2000a,b). The periods necessary for the 
biochemical changes to return to normal are variable and depend on 
numerous aspects of the biology of the species and of the sound 
stimulus.
    Behavioral Effects--Behavioral effects include changes in the 
distribution, migration, mating, and catchability of fish populations. 
Studies investigating the possible effects of sound (including seismic 
survey sound) on fish behavior have been conducted on both uncaged and 
caged individuals (e.g., Chapman and Hawkins, 1969; Pearson et al., 
1992; Santulli et al., 1999; Wardle et al., 2001; Hassel et al., 2003). 
Typically, in these studies fish exhibited a sharp startle response at 
the onset of a sound followed by habituation and a return to normal 
behavior after the sound ceased.
    The Minerals Management Service (MMS, 2005) assessed the effects of 
a proposed seismic survey in Cook Inlet. The seismic survey proposed 
using three vessels, each towing two, four-airgun arrays ranging from 
1,500 to 2,500 in\3\. MMS noted that the impact to fish populations in 
the survey area and adjacent waters would likely be very low and 
temporary. MMS also concluded that seismic surveys may displace the 
pelagic fishes from the area temporarily when airguns are in use. 
However, fishes displaced and avoiding the airgun noise are likely to 
backfill the survey area in minutes to hours after cessation of seismic 
testing. Fishes not dispersing from the airgun noise (e.g., demersal 
species) may startle and move short distances to avoid airgun 
emissions.
    In general, any adverse effects on fish behavior or fisheries 
attributable to seismic testing may depend on the species in question 
and the nature of the fishery (season, duration, fishing method). They 
may also depend on the age of the fish, its motivational state, its 
size, and numerous other factors that are difficult, if not impossible, 
to quantify at this point, given such limited data on effects of 
airguns on fish, particularly under realistic at-sea conditions.

Anticipated Effects on Invertebrates

    The existing body of information on the impacts of seismic survey 
sound on marine invertebrates is very limited. However, there is some 
unpublished and very limited evidence of the potential for adverse 
effects on invertebrates, thereby justifying further discussion and 
analysis of this issue. The three types of potential effects of 
exposure to seismic surveys on marine invertebrates are pathological, 
physiological, and behavioral. Based on the physical structure of their 
sensory organs, marine invertebrates appear to be specialized to 
respond to particle displacement components of an impinging sound field 
and not to the pressure component (Popper et al., 2001).
    The only information available on the impacts of seismic surveys on 
marine invertebrates involves studies of individuals; there have been 
no studies at the population scale. Thus, available information 
provides limited insight on possible real-world effects at the regional 
or ocean scale. The most important aspect of potential impacts concerns 
how exposure to seismic survey sound ultimately affects invertebrate 
populations and their viability, including availability to fisheries.
    Literature reviews of the effects of seismic and other underwater 
sound on invertebrates were provided by Moriyasu et al. (2004) and 
Payne et al. (2008). The following sections provide a synopsis of 
available information on the effects of exposure to seismic survey 
sound on species of decapod crustaceans and cephalopods, the two 
taxonomic groups of invertebrates on which most such studies have been 
conducted. The available information is from studies with variable 
degrees of scientific soundness and from anecdotal information. A more 
detailed review of the literature on the effects of seismic survey 
sound on invertebrates is provided in Appendix F of NSF's EA.
    Pathological Effects--In water, lethal and sub-lethal injury to 
organisms exposed to seismic survey sound appears to depend on at least 
two features of the sound source: (1) the received peak pressure; and 
(2) the time required for the pressure to rise and decay. Generally, as 
received pressure increases, the period for the pressure to rise and 
decay decreases, and the chance of acute pathological effects 
increases. For the type of airgun array planned for the proposed 
program, the pathological (mortality) zone for crustaceans and 
cephalopods is expected to be within a few meters of the seismic 
source, at most; however, very few specific data are available on 
levels of seismic signals that might damage these animals. This premise 
is based on the peak pressure and rise/decay time characteristics of 
seismic airgun arrays currently in use around the world.
    Some studies have suggested that seismic survey sound has a limited 
pathological impact on early developmental stages of crustaceans 
(Pearson et al., 1994; Christian et al., 2003; DFO, 2004). However, the 
impacts appear to be either temporary or insignificant compared to what 
occurs under natural conditions. Controlled field experiments on adult 
crustaceans (Christian et al., 2003, 2004; DFO, 2004) and adult 
cephalopods (McCauley et al., 2000a,b) exposed to seismic survey sound 
have not resulted in any significant pathological impacts on the

[[Page 58275]]

animals. It has been suggested that exposure to commercial seismic 
survey activities has injured giant squid (Guerra et al., 2004), but 
the article provides little evidence to support this claim. Tenera 
Environmental (2011b) reported that Norris and Mohl (1983, summarized 
in Mariyasu et al., 2004) observed lethal effects in squid (Loligo 
vulgaris) at levels of 246 to 252 dB after 3 to 11 minutes.
    Andre et al. (2011) exposed four species of cephalopods (Loligo 
vulgaris, Sepia officinalis, Octopus vulgaris, and Ilex coindetii), 
primarily cuttlefish, to two hours of continuous 50 to 400 Hz 
sinusoidal wave sweeps at 157+/-5 dB re 1 [mu]Pa while captive in 
relatively small tanks. They reported morphological and ultrastructural 
evidence of massive acoustic trauma (i.e., permanent and substantial 
alterations [lesions] of statocyst sensory hair cells) to the exposed 
animals that increased in severity with time, suggesting that 
cephalopods are particularly sensitive to low frequency sound. The 
received SPL was reported as 157+/-5 dB re 1 [mu]Pa, with peak levels 
at 175 dB re 1 [mu]Pa. As in the McCauley et al. (2003) paper on 
sensory hair cell damage in pink snapper as a result of exposure to 
seismic sound, the cephalopods were subjected to higher sound levels 
than they would be under natural conditions, and they were unable to 
swim away from the sound source.
    Physiological Effects--Physiological effects refer mainly to 
biochemical responses by marine invertebrates to acoustic stress. Such 
stress potentially could affect invertebrate populations by increasing 
mortality or reducing reproductive success. Primary and secondary 
stress responses (i.e., changes in haemolymph levels of enzymes, 
proteins, etc.) of crustaceans have been noted several days or months 
after exposure to seismic survey sounds (Payne et al., 2007). It was 
noted however, that no behavioral impacts were exhibited by crustaceans 
(Christian et al., 2003, 2004; DFO, 2004). The periods necessary for 
these biochemical changes to return to normal are variable and depend 
on numerous aspects of the biology of the species and of the sound 
stimulus.
    Behavioral Effects--There is increasing interest in assessing the 
possible direct and indirect effects of seismic and other sounds on 
invertebrate behavior, particularly in relation to the consequences for 
fisheries. Changes in behavior could potentially affect such aspects as 
reproductive success, distribution, susceptibility to predation, and 
catchability by fisheries. Studies investigating the possible 
behavioral effects of exposure to seismic survey sound on crustaceans 
and cephalopods have been conducted on both uncaged and caged animals. 
In some cases, invertebrates exhibited startle responses (e.g., squid 
in McCauley et al., 2000a,b). In other cases, no behavioral impacts 
were noted (e.g., crustaceans in Christian et al., 2003, 2004; DFO 
2004). There have been anecdotal reports of reduced catch rates of 
shrimp shortly after exposure to seismic surveys; however, other 
studies have not observed any significant changes in shrimp catch rate 
(Andriguetto-Filho et al., 2005). Similarly, Parry and Gason (2006) did 
not find any evidence that lobster catch rates were affected by seismic 
surveys. Any adverse effects on crustacean and cephalopod behavior or 
fisheries attributable to seismic survey sound depend on the species in 
question and the nature of the fishery (season, duration, fishing 
method).

Proposed Mitigation

    In order to issue an Incidental Take Authorization (ITA) under 
section 101(a)(5)(D) of the MMPA, NMFS must set forth the permissible 
methods of taking pursuant to such activity, and other means of 
effecting the least practicable impact on such species or stock and its 
habitat, paying particular attention to rookeries, mating grounds, and 
areas of similar significance, and the availability of such species or 
stock for taking for certain subsistence uses.
    L-DEO and PG&E have reviewed the following source documents and 
have incorporated a suite of appropriate mitigation measures into their 
project description.
    (1) Protocols used during previous NSF and USGS-funded seismic 
research cruises as approved by NMFS and detailed in the recently 
completed Final Programmatic Environmental Impact Statement/Overseas 
Environmental Impact Statement for Marine Seismic Research Funded by 
the National Science Foundation or Conducted by the U.S. Geological 
Survey;
    (2) Previous IHA applications and IHAs approved and authorized by 
NMFS; and
    (3) Recommended best practices in Richardson et al. (1995), Pierson 
et al. (1998), and Weir and Dolman, (2007).
    To reduce the potential for disturbance from acoustic stimuli 
associated with the activities, L-DEO, PG&E and/or its designees have 
proposed to implement the following mitigation measures for marine 
mammals:
    (1) Vessel-based Marine Wildlife Contingency Plan;
    (2) Scheduling to avoid areas of high marine mammal activity;
    (3) Speed and course alterations;
    (4) Proposed exclusion zones around the sound source;
    (5) Power-down procedures;
    (6) Shut-down procedures;
    (7) Ramp-up procedures; and
    (8) Morro Bay stock harbor porpoise mitigation, monitoring, and 
adaptive management that will detect significant impacts to harbor 
porpoises in real time in order to trigger appropriate mitigation 
measures (e.g., suspension of seismic operations).
    Vessel-based Marine Wildlife Contingency Plan--The vessel-based 
seismic operations of the PG&E's Marine Wildlife Contingency Plan are 
designed to meet the anticipated Federal and State regulatory 
requirements. The objectives of the program will be:
     To minimize any potential disturbance to marine mammals 
and ensure all regulatory requirements are followed;
     To document observations of the proposed seismic survey on 
marine mammals; and
     To collect baseline data on the occurrence and 
distribution of marine mammals in the proposed study area.
    Proposed survey design features include:
     Timing and locating seismic operations to avoid potential 
interference with the annual peak of the gray whale migration period;
     Limiting the size of the seismic sound source to minimize 
energy introduced into the marine environment; and
     Establishing buffer and exclusion zones radii based on 
modeling results of the proposed sound sources.
    The Marine Wildlife Contingency Plan will be implemented by a team 
of NMFS-qualified PSOs. PSOs will be stationed aboard the source and 
support vessels through the duration of the proposed project. Reporting 
of the results of the vessel-based mitigation and monitoring program 
will include the estimation of the number of takes.
    The vessel-based work will provide:
     Information needed to estimate the number of potential 
takes of marine mammals by harassment, which must be reported to NMFS 
and USFWS;
     Data on the occurrence, distribution, and activities of 
marine mammals in the areas where the proposed seismic operations are 
conducted; and
     Information to compare the distances, distributions, 
behavior, and movements of marine mammals relative

[[Page 58276]]

to the source vessel at times with and without airgun activity.
    Scheduling to Avoid Areas of High Marine Mammal Activity--PG&E 
proposes to conduct offshore seismic surveys from October 15 through 
December 31, 2012, with airgun operations taking place from November 1 
through December 31, 2012, to coincide with the reduced number of 
cetaceans in the area, and outside the peak gray whale annual migration 
period. This timeframe also is outside the breeding and pupping periods 
for the Pacific harbor seal (March to June) and California sea lion 
(May to late July), both of which have rookeries inshore, but adjacent 
to the proposed project area. No other pinnipeds breed in the project 
area. The 2012 survey timing has also been refined to address the 
breeding activity of the resident Morro Bay stock of harbor porpoises. 
As such, active use of airguns will not be started until November 1, 
2012, which will minimize exposure of nursing harbor porpoise to 
seismic operations.
    Speed and Course Alterations--If a marine mammal is detected 
outside the exclusion zone and, based on its position and direction of 
travel, is likely to enter the exclusion zone, changes of the vessel's 
speed and course will be considered if this does not compromise 
operational safety. For marine seismic surveys towing large streamer 
arrays, however, course alterations are not typically implemented due 
to the vessel's limited maneuverability. After any such speed and/or 
course alteration is begun, the marine mammal activities and movements 
relative to the seismic vessel will be closely monitored to ensure that 
the marine mammal does not approach within the exclusion zone. If the 
marine mammal appears likely to enter the exclusion zone, further 
mitigation actions will be taken, including a power-down and/or shut-
down of the airgun(s).
    Proposed Exclusion Zones--L-DEO and PG&E use radii to designate 
exclusion and buffer zones and to estimate take for marine mammals. 
Table 1 (presented earlier in this document) shows the distances at 
which one would expect to receive three sound levels (160, 180, and 190 
dB) from the 18 airgun array and a single airgun. The 180 dB and 190 dB 
level shut-down criteria are applicable to cetaceans and pinnipeds, 
respectively, as specified by NMFS (2000). L-DEO and PG&E used these 
levels to establish the exclusion and buffer zones.
    If the PSVO detects marine mammal(s) within or about to enter the 
appropriate exclusion zone, the Langseth crew will immediately power-
down the airgun array, or perform a shut-down if necessary (see ``Shut-
down Procedures''). Table 1 summarizes the calculated distances at 
which sound levels (160, 180, and 190 dB [rms]) are expected to be 
received from the 18 airgun array operating in upslope, downslope, and 
alongshore depths (although only the upslope radii will be used for the 
160 and 180 dB isopleths and the alongshore radii will be used for the 
190 dB isopleth, as these are considered the most conservative) and the 
single airgun operating in shallow, intermediate, and deep water depths 
(all survey boxes are within water depths of 400 m or less). Received 
sound levels have been calculated by L-DEO, in relation to distance and 
direction from the airguns, for the 18 airgun array and for the single 
1900LL 40 in\3\ airgun, which will be used during power-downs.
    A detailed description of the modeling effort for the 18 airgun 
array by Greeneridge Sciences, Inc. is presented in Appendix A of the 
IHA application and NSF EA. Modeled received sound levels prepared by 
L-DEO will be used for the single airgun.
    If the PSVO detects marine mammal(s) within or about to enter the 
appropriate exclusion zone, the airguns will be powered-down (or shut-
down, if necessary) immediately.
    At the initiation of the 3D seismic survey, direct measurements 
will be taken of the received levels of underwater sound versus 
distance and direction from the airgun source vessel using calibrated 
hydrophones (i.e., a sound source verification test). The acoustic data 
will be analyzed as quickly as reasonably practicable in the field and 
used to verify and adjust the buffer and exclusion zone distances. The 
field report will be made available to NMFS and PSOs within 120 hours 
of completing the measurements.
    To augment visual observations on the Langseth, two scout vessels 
with a minimum of three NMFS-qualified PSOs onboard each, shall be 
positioned adjacent to the Langseth to monitor the buffer and exclusion 
zones for mitigation-monitoring purposes. The PSOs onboard the scout 
vessels will report to the PSOs onboard the Langseth if any marine 
mammals are observed.
    Power-down Procedures--A power-down involves decreasing the number 
of airguns in use to one airgun, such that the radius of the 180 dB (or 
190 dB) zone is decreased to the extent that the observed marine 
mammal(s) are no longer in or about to enter the exclusion zone for the 
full airgun array. A power-down of the airgun array can also occur when 
the vessel is moving from the end of one seismic trackline to the start 
of the next trackline. During a power-down for mitigation, L-DEO and 
PG&E will operate one airgun. The continued operation of one airgun is 
intended to (a) alert marine mammals to the presence of the seismic 
vessel in the area; and, (b) retain the option of initiating a ramp-up 
to full operations under poor visibility conditions. In contrast, a 
shut-down occurs when all airgun activity is suspended.
    If the PSVO detects a marine mammal outside the exclusion zone and 
is likely to enter the exclusion zone, L-DEO and PG&E will power-down 
the airguns to reduce the size of the 180 dB exclusion zone before the 
animal is within the exclusion zone. Likewise, if a mammal is already 
within the exclusion zone, when first detected L-DEO and PG&E will 
power-down the airguns immediately. During a power-down of the airgun 
array, L-DEO ad PG&E will operate the single 40 in\3\ airgun, which has 
a smaller exclusion zone. If the PSVO detects a marine mammal within or 
near the smaller exclusion zone around that single airgun (see Table 
1), L-DEO and PG&E will shut-down the airgun (see next section).
    Following a power-down, the Langseth will not resume full airgun 
activity until the marine mammal has cleared the 180 or 190 dB 
exclusion zone (see Table 1). The PSO will consider the animal to have 
cleared the exclusion zone if:
     The observer has visually observed the animal leave the 
exclusion zone, or
     An observer has not sighted the animal within the 
exclusion zone for 15 minutes for species with shorter dive durations 
(i.e., small odontocetes or pinnipeds), or 30 minutes for species with 
longer dive durations (i.e., mysticetes and large odontocetes, 
including sperm, pygmy sperm, dwarf sperm, and beaked whales); or
     The vessel has transited outside the original 180 dB 
exclusion zone after an 8 minute period minute wait period.
    The Langseth crew will resume operating the airguns at full power 
after 15 minutes of sighting any species with short dive durations 
(i.e., small odontocetes or pinnipeds). Likewise, the crew will resume 
airgun operations at full power after 30 minutes of sighting any 
species with longer dive durations (i.e., mysticetes and large 
odontocetes, including sperm, pygmy sperm, dwarf sperm, and beaked 
whales).
    Because the vessel has transited away from the vicinity of the 
original sighting during the 8 minute period, implementing ramp-up 
procedures for the full array after an extended power-down (i.e., 
transiting for an additional

[[Page 58277]]

35 minutes from the location of initial sighting) would not 
meaningfully increase the effectiveness of observing marine mammals 
approaching or entering the exclusion zone for the full source level 
and would not further minimize the potential for take. The Langseth's 
PSOs are continually monitoring the exclusion zone for the full source 
level while the mitigation airgun is firing. On average, PSOs can 
observe to the horizon (10 km or 5.4 nmi) from the height of the 
Langseth's observation deck and should be able to state with a 
reasonable degree of confidence whether a marine mammal would be 
encountered within this distance before resuming airgun operations at 
full power.
    Shut-down Procedures--L-DEO and PG&E will shut-down the operating 
airgun(s) if a marine mammal is seen within or approaching the 
exclusion zone for the single airgun. L-DEO will implement a shut-down:
    (1) If an animal enters the exclusion zone of the single airgun 
after L-DEO has initiated a power-down; or
    (2) If an animal is initially seen within the exclusion zone of the 
single airgun when more than one airgun (typically the full airgun 
array) is operating (and it is not practical or adequate to reduce 
exposure to less than 180 dB [rms]).
    Considering the conservation status for the North Pacific right 
whale, the airguns will be shut-down immediately in the unlikely event 
that this species is observed, regardless of the distance from the 
Langseth. Ramp-up will only begin if the North Pacific right whale has 
not been seen for 30 minutes.
    Following a shut-down in excess of 8 minutes, the Langseth crew 
will initiate a ramp-up with the smallest airgun in the array (40 
in\3\). The crew will turn on additional airguns in a sequence such 
that the source level of the array will increase in steps not exceeding 
6 dB per five-minute period over a total duration of approximately 30 
minutes. During ramp-up, the PSOs will monitor the exclusion zone, and 
if he/she sights a marine mammal, the Langseth crew will implement a 
power-down or shut-down as though the full airgun array were 
operational.
    During periods of active seismic operations, there are occasions 
when the Langseth crew will need to temporarily shut-down the airguns 
due to equipment failure or for maintenance. In this case, if the 
airguns are inactive longer than eight minutes, the crew will follow 
ramp-up procedures for a shut-down described earlier and the PSOs will 
monitor the full exclusion zone and will implement a power-down or 
shut-down if necessary.
    If the full exclusion zone is not visible to the PSO for at least 
30 minutes prior to the start of operations in either daylight or 
nighttime, the Langseth crew will not commence ramp-up unless at least 
one airgun (40 in\3\ or similar) has been operating during the 
interruption of seismic survey operations. Given these provisions, it 
is likely that the vessel's crew will not ramp-up the airgun array from 
a complete shut-down at night or in thick fog, because the outer part 
of the zone for that array will not be visible during those conditions.
    If one airgun has operated during a power-down period, ramp-up to 
full power will be permissible at night or in poor visibility, on the 
assumption that marine mammals will be alerted to the approaching 
seismic vessel by the sounds from the single airgun and could move 
away. The vessel's crew will not initiate ramp-up of the airguns if a 
marine mammal is sighted within or near the applicable exclusion zones 
during the day or close to the vessel at night.
    Ramp-up Procedures--Ramp-up of an airgun array provides a gradual 
increase in sound levels, and involves a step-wise increase in the 
number and total volume of airguns firing until the full volume of the 
airgun array is achieved. The purpose of a ramp-up is to ``warn'' 
marine mammals in the vicinity of the airguns, and to provide the time 
for them to leave the area and thus avoid any potential injury or 
impairment of their hearing abilities. L-DEO and PG&E will follow a 
ramp-up procedure when the airgun array begins operating after an 8 
minute period without airgun operations or when a power-down shut down 
has exceeded that period. L-DEO and PG&E considered proposing that, for 
the present cruise, this period would be approximately two minutes. 
Since from a practical and operational standpoint this time period is 
considered too brief, L-DEO and PG&E propose to use 8 minutes, which is 
a time period used during previous 2D surveys. L-DEO has used similar 
periods (approximately 8 to 10 min) during previous L-DEO surveys.
    Ramp-up will begin with the smallest airgun in the array (40 
in\3\). Airguns will be added in a sequence such that the source level 
of the array will increase in steps not exceeding six dB per five 
minute period over a total duration of approximately 30 to 35 minutes. 
During ramp-up, the PSOs will monitor the exclusion zone, and if marine 
mammals are sighted, L-DEO will implement a power-down or shut-down as 
though the full airgun array were operational.
    If the complete exclusion zone has not been visible for at least 30 
minutes prior to the start of operations in either daylight or 
nighttime, L-DEO will not commence the ramp-up unless at least one 
airgun (40 in\3\ or similar) has been operating during the interruption 
of seismic survey operations. Given these provisions, it is likely that 
the airgun array will not be ramped-up from a complete shut-down at 
night or in thick fog, because the outer part of the exclusion zone for 
that array will not be visible during those conditions. If one airgun 
has operated during a power-down period, ramp-up to full power will be 
permissible at night or in poor visibility, on the assumption that 
marine mammals will be alerted to the approaching seismic vessel by the 
sounds from the single airgun and could move away. L-DEO and PG&E will 
not initiate a ramp-up of the airguns if a marine mammal is sighted 
within or near the applicable exclusion zones.

Use of a Small-Volume Airgun During Turns and Maintenance

    Throughout the seismic survey, particularly during turning 
movements, and short-duration equipment maintenance activities, L-DEO 
and PG&E will employ the use of a small-volume airgun (i.e., mitigation 
airgun) to deter marine mammals from being within the immediate area of 
the seismic operations. The mitigation airgun would be operated at 
approximately one shot per minute and would not be operated for longer 
than three hours in duration (turns may last two to three hours for the 
proposed project).
    During turns or brief transits (e.g., less than 2 hours) between 
seismic tracklines, one airgun will continue operating. The ramp-up 
procedure will still be followed when increasing the source levels from 
one airgun to the full airgun array. However, keeping one airgun firing 
will avoid the prohibition of a ``cold start'' during darkness or other 
periods of poor visibility. Through use of this approach, seismic 
operations may resume without the 30 minute observation period of the 
full exclusion zone required for a ``cold start,'' and without ramp-up 
if operating with the mitigation airgun for under 8 minutes, or with 
ramp-up if operating with the mitigation airgun over 8 minutes. PSOs 
will be on duty whenever the airguns are firing during daylight, and at 
night during the 30 minute periods prior to ramp-ups as well as during 
ramp-ups or when the Protected Species Acoustic Observer detects the 
presence of marine mammals within the exclusion zone.

[[Page 58278]]

Nighttime Survey Areas

    Nighttime operations will be restricted to areas in which marine 
mammal abundance is low based on daytime observations (i.e., vessel and 
period aerial data) and historical distribution patterns. Data 
collection along inshore tracklines and near Church Rock (35[deg] 
20.675' North, 120[deg] 59.049' West) will be done during daylight 
hours to the extent possible. If nighttime survey operations are 
located within the 40 m (131 ft) depth contour, PSOs will visually 
monitor the area forward of the vessel with the aid of binoculars, and 
the forward-looking infrared system available on the Langseth.

Harbor Porpoise Mitigation, Monitoring, and Adaptive Management Plan

    Because of heightened concern over impacts from seismic operations 
to harbor porpoises from the proposed action, NMFS coordinated closely 
with PG&E to develop a comprehensive and precautionary monitoring, 
mitigation, and adaptive management framework. This plan, which PG&E 
has agreed to operationally and financially support, is designed to 
detect significant responses of harbor porpoises to the activity that 
can be used to trigger management actions in real-time and allow the 
activity to proceed in a cautious manner in light of some uncertainty 
regarding how this species will respond to the activity. Additional 
measures include:
     Implementation of an extended initial ramp-up (around the 
length of time it takes to run the first transect of the aerial survey) 
at the beginning of each of the two survey boxes.
     Ensuring that airgun operations for each survey box begin 
in the daylight.
    Data collected during pre-activity survey operations and on-going 
operational monitoring activities will be used during the proposed 
seismic operations to adjust or redirect seismic operations should 
significant adverse impacts be observed to marine mammals in the 
proposed project area. The Adaptive Management Plan will be finalized 
in consultation with resource agencies involved in the permitting and 
monitoring activities associated with the proposed 2012 seismic 
operations. Information sources used as part of this plan will include, 
but not be limited to the following:
     Pre-activity and weekly aerial surveys (see Appendix G of 
the IHA application);
     Sound source verification study;
     Visual monitoring by PSOs onboard vessels;
     NMFS Morro Bay stock of Harbor Porpoise Monitoring Program 
(see Appendix D of the IHA application), which will use aerial surveys, 
C-PODS (passive acoustic devices tuned to detect high frequency harbor 
porpoise vocalizations), and moored hydrophones (tuned to identify 
received levels of seismic signals) to detect broader scale harbor 
porpoise responses to seismic surveys; and
     Marine Mammal Stranding Response Plan (see Appendix F of 
the IHA application), which will utilize response personnel and 
necessary equipment to monitor the action area for behaviors suggestive 
of stranding responses, and subsequently run appropriate tests if an 
event occurs.
    Triggers for Adaptive Management--Below are the situations in which 
suspension of seismic airgun operations would be required. Following 
suspension of activities for any of the situations outlined below, NMFS 
and our stranding network partners will further evaluate available 
information, including new information collected while seismic 
operations are suspended, and NMFS will coordinate with PG&E and L-DEO 
to determine if and how seismic operations may continue. The triggers 
that have been identified are as follows:
     The seismic survey will be suspended if the aerial surveys 
or acoustic detections show that moderate to large numbers of the Morro 
Bay stock of harbor porpoises, have been pushed out of their primary 
(core) habitat and/or outside of their normal stock range. Numerical 
thresholds for this, including (a) decreased densities in core habitat 
and/or (b) increased densities in secondary habitat (or beyond, e.g., 
Point Conception) will have to be identified based in part on the fine-
scale ``baseline'' surveys planned for October, before seismic 
operations start, and NMFS's knowledge about their core habitat from 
the coarser historical aerial survey data.
     The seismic survey will be suspended if unusual behavior 
for harbor porpoises is observed that would suggest there is severe 
disturbance or stress/injury. Details of this criterion are difficult 
to predict, but harbor porpoises usually occur in loosely aggregated 
groups of 1 to 5 individuals, with characteristic surfacing behaviors. 
So, for example, a large, tight group of 50 to 100 individuals rafting 
or bunched in an unusual area would be of concern.
     A mass stranding (i.e., 2 or more animals that 
simultaneously strand, other than cow-calf pairs) or unusual nearshore 
milling (``near mass stranding'') of any cetacean species. At a 
minimum, the shut-down of all seismic airgun operations would continue 
until the disposition of the animals was complete; this could involve 
herding offshore, refloating/transporting/herding, transport to 
rehabilitation, euthanasia, or any combination of the above. Shut-down 
procedures will remain in effect until NMFS determines that, and 
advises PG&E that, all live animals have left the geographic area 
(either of their volition or following herding).
     If 2 cetaceans within one day, 3 or more cetaceans within 
a week, or 5 or more pinniped within a week are newly detected stranded 
(sick, injured, in need of medical attention, or dead) on the beach or 
floating incapacitated or dead within the impact zone during the period 
of seismic operations, the following would occur:
    [cir] For live stranded animals, the stranding team would attempt 
to capture the animals and perform a Phase 1 examination, including 
auditory evoked potential (AEP) testing of all odontocetes, and any 
clinical tests deemed necessary by the attending veterinarian. If the 
animal(s) are determined to be candidates for immediate release (either 
from the original stranding location or following transport to a new 
location), shut-down may be needed until the release is complete. If 
the animal is determined to be a candidate for rehabilitation and the 
initial examination is inconclusive regarding a reason for stranding, 
Phase 2 investigations will be conducted.
    [cir] For all dead stranded animals, the stranding team would 
attempt to recover the carcass(es) and perform a detailed necropsy with 
diagnostic imaging scans to rule out obvious cause of death (e.g., a 
Phase 1 investigation), as appropriate given the decomposition rate of 
the animal and other logistical constraints (size, weight, location, 
etc.). Then, if Phase 1 tests are inconclusive and the animal(s) is 
(are) in good body condition, Phase 2 investigations will be conducted.
    [cir] In either case, if Phase 2 investigations are warranted for 
enough animals to meet the initial numerical criteria, seismic 
operations will be suspended.
     Strandings of single marine mammals with signs of acoustic 
trauma or barotrauma without another etiology would require a 
suspension of seismic operations.
     A ship-strike of a marine mammal by any of the vessels 
involved in the seismic survey (including chase/support vessels) would 
result in a suspension of seismic operations.
    Data from the proposed seismic operations 2012 may also be used to 
revise proposed survey operations

[[Page 58279]]

within Survey Box 1, or associated mitigation and monitoring, which 
have been proposed to be conducted in 2013 as a result of consultation 
under the MMPA with NMFS.
    NMFS has carefully evaluated the applicant's proposed mitigation 
measures and has considered a range of other measures in the context of 
ensuring that NMFS prescribes the means of effecting the least 
practicable adverse impact on the affected marine mammal species and 
stocks and their habitat. NMFS's evaluation of potential measures 
included consideration of the following factors in relation to one 
another:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure is expected to minimize adverse impacts 
to marine mammals;
    (2) The proven or likely efficacy of the specific measure to 
minimize adverse impacts as planned; and
    (3) The practicability of the measure for applicant implementation.

Proposed Monitoring and Reporting

    In order to issue an ITA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth ``requirements pertaining to 
the monitoring and reporting of such taking.'' The MMPA implementing 
regulations at 50 CFR 216.104(a)(13) indicate that requests for IHAs 
must include the suggested means of accomplishing the necessary 
monitoring and reporting that will result in increased knowledge of the 
species and of the level of taking or impacts on populations of marine 
mammals that are expected to be present in the action area.

Proposed Monitoring

    L-DEO and PG&E propose to sponsor marine mammal monitoring during 
the proposed project, in order to implement the proposed mitigation 
measures that require real-time monitoring, and to satisfy the 
anticipated monitoring requirements of the IHA. L-DEO and PG&E's 
proposed ``Monitoring Plan'' is described below this section. L-DEO and 
PG&E understand that this monitoring plan will be subject to review by 
NMFS, and that refinements may be required. The monitoring work 
described here has been planned as a self-contained project independent 
of any other related monitoring projects that may be occurring 
simultaneously in the same regions. L-DEO and PG&E are prepared to 
discuss coordination of their monitoring program with any related work 
that might be done by other groups insofar as this is practical and 
desirable.
Aerial Surveys
    PG&E proposes to conduct aerial surveys for large cetaceans in 
conjunction with the proposed seismic survey operations and in 
accordance with the requirements established by the California State 
Lands Commission Environmental Impact Report mitigation measures. In 
addition to the PG&E aerial surveys focusing on large cetaceans (flying 
above 305 m [1,000 ft]), NMFS/USFWS will be conducting low level aerial 
surveys designed to monitor southern sea otter and the Morro Bay stock 
of harbor porpoise movements through a separate project funded by PG&E. 
These NMFS/USFWS aerial survey operations will be conducted in close 
coordination with the PG&E aerial surveys, but under existing permits. 
The information generated by these two aerial survey operations will be 
used to inform the proposed project's Adaptive Management Plan. 
Discussions between PG&E and NMFS/USFWS are currently ongoing regarding 
the coordination of the aerial surveys and the potential for NMFS/USFWS 
to undertake all aerial survey operations. More information regarding 
the NMFS/USFWS aerial survey operations are provided in Appendix D and 
E of the IHA application. Two PSO's will be used on all aerial surveys. 
Aerial survey data and observations noted by PSOs will be provided to 
the agencies for review and consideration of potential refinements to 
mitigation measures. The general purpose of these aerial survey efforts 
are to:
     Identify direction of travel and corridors utilized by 
marine mammals relative to the proposed survey area;
     Identify locations within the proposed survey area that 
support aggregations of marine mammals;
     Identify the relative abundance of marine mammals within 
the proposed survey area; and
     Document changes in the behavior and distribution of 
marine mammals in the area before, during and after the proposed 
seismic operations.
    With the proposed timing of the seismic operations, aerial surveys 
will be conducted prior to the initiation of, during, and after the 
proposed project. The aerial surveys will pay particular attention will 
be directed to the identification of the presence of large cetaceans 
(i.e., blue, fin, and humpback whales) due to the likelihood that those 
species will be present in the project area. Aerial survey operations 
focused on large cetaceans will include the following components:
     Approximately 5 to 10 days prior to the start of seismic 
operations, an aerial survey will be flown to establish a baseline for 
numbers and distribution of marine mammals in the project area;
     Aerial surveys will be conducted weekly during the seismic 
operations to assist in the identification of marine mammals within the 
project buffer and exclusion zones. Aerial monitors will be in direct 
communications with ship-based monitors to assess the effectiveness of 
monitoring operations. Based on the results of these coordinated 
monitoring efforts, the need for additional aerial surveys will be 
evaluated; and
     Approximately 5 to 10 days following the completion of the 
offshore seismic operations, a final aerial survey will be conducted to 
document the number and distribution of marine mammals in the project 
area. These data will be used in comparison with original survey data 
completed prior to the seismic operations.
    A copy of the draft Aerial Survey Plan, that focuses particular 
attention on the presence of large cetaceans, is provided in Appendix G 
of the IHA application.
Vessel-Based Visual Monitoring
    PSVOs will be based aboard the seismic source vessel and will watch 
for marine mammals near the vessel during daytime airgun operations and 
during any ramp-ups of the airguns at night. PSVOs will also watch for 
marine mammals near the seismic vessel for at least 30 minutes prior to 
the start of airgun operations after an extended shut-down (i.e., 
greater than approximately 8 minutes for this proposed cruise). When 
feasible, PSVOs will conduct observations during daytime periods when 
the seismic system is not operating for comparison of sighting rates 
and behavior with and without airgun operations and between acquisition 
periods. Based on PSVO observations, the airguns will be powered-down 
or shut-down when marine mammals are observed within or about to enter 
a designated exclusion zone. The exclusion zone is a region in which a 
possibility exists of adverse effects on animal hearing or other 
physical effects.
    During seismic operations off the central coast of California, at 
least five PSOs (PSVO and/or Protected Species Acoustic Observer 
[PSAO]) will be based aboard the Langseth. In addition, three PSO's 
will be positioned on each of the survey/chase vessels (which at this 
time is anticipated to be two vessels). L-DEO will appoint the PSOs 
with NMFS's concurrence. Observations

[[Page 58280]]

will take place during ongoing daytime operations and nighttime ramp-
ups of the airguns. During the majority of seismic operations, two 
PSVOs will be on duty from the observation tower (i.e., the best 
available vantage point on the source vessel) to monitor marine mammals 
near the seismic vessel. Use of two simultaneous PSVOs will increase 
the effectiveness of detecting animals near the source vessel. However, 
during meal times and bathroom breaks, it is sometimes difficult to 
have two PSVOs on effort, but at least one PSVO will be on duty. 
PSVO(s) will be on duty in shifts no longer than 4 hours in duration.
    Two PSVOs will also be on visual watch during all daytime ramp-ups 
of the seismic airguns. A third PSAO will monitor the PAM equipment 24 
hours a day to detect vocalizing marine mammals present in the action 
area. In summary, a typical daytime cruise would have scheduled two 
PSVOs on duty from the observation tower, and a third PSAO on PAM. 
Other crew will also be instructed to assist in detecting marine 
mammals and implementing mitigation requirements (if practical). Before 
the start of the seismic survey, the crew will be given additional 
instruction on how to do so.
    The Langseth is a suitable platform for marine mammal observations. 
When stationed on the observation platform, the eye level will be 
approximately 21.5 m (70.5 ft) above sea level, and the PSVO will have 
a good view around the entire vessel. During daytime, the PSVOs will 
scan the area around the vessel systematically with reticle binoculars 
(e.g., 7 x 50 Fujinon), Big-eye binoculars (25 x 150), and with the 
naked eye. Laser range-finding binoculars (Leica LRF 1200 laser 
rangefinder or equivalent) will be available to assist with distance 
estimation. Those are useful in training observers to estimate 
distances visually, but are generally not useful in measuring distances 
to animals directly; that is done primarily with the reticles in the 
binoculars.
    When marine mammals are detected within or about to enter the 
designated exclusion zone, the airguns will immediately be powered-down 
or shut-down if necessary. The PSVO(s) will continue to maintain watch 
to determine when the animal(s) are outside the exclusion zone by 
visual confirmation. Airgun operations will not resume until the animal 
is confirmed to have left the exclusion zone, or if not observed after 
15 minutes for species with shorter dive durations (small odontocetes 
and pinnipeds) or 30 minutes for species with longer dive durations 
(mysticetes and large odontocetes, including sperm, pygmy sperm, dwarf 
sperm, killer, and beaked whales).
Vessel-Based Passive Acoustic Monitoring
    Vessel-based, towed PAM will complement the visual monitoring 
program, when practicable. Visual monitoring typically is not effective 
during periods of poor visibility or at night, and even with good 
visibility, is unable to detect marine mammals when they are below the 
surface or beyond visual range. Passive acoustical monitoring can be 
used in addition to visual observations to improve detection, 
identification, and localization of cetaceans. The passive acoustic 
monitoring will serve to alert visual observers (if on duty) when 
vocalizing cetaceans are detected. It is only useful when marine 
mammals call, but it can be effective either by day or by night, and 
does not depend on good visibility. It will be monitored in real time 
so that the PSVOs can be advised when cetaceans are detected.
    The PAM system consists of hardware (i.e., hydrophones) and 
software. The ``wet end'' of the system consists of a towed hydrophone 
array that is connected to the vessel by a tow cable. The tow cable is 
250 m (820.2 ft) long, and the hydrophones are fitted in the last 10 m 
(32.8 ft) of cable. A depth gauge is attached to the free end of the 
cable, and the cable is typically towed at depths less than 20 m (65.6 
ft). The array will be deployed from a winch located on the back deck. 
A deck cable will connect from the winch to the main computer 
laboratory where the acoustic station, signal conditioning, and 
processing system will be located. The acoustic signals received by the 
hydrophones are amplified, digitized, and then processed by the 
Pamguard software. The system can detect marine mammal vocalizations at 
frequencies up to 250 kHz.
    One PSAO, an expert bioacoustician in addition to the four PSVOs, 
with primary responsibility for PAM, will be onboard the Langseth. The 
towed hydrophones will ideally be monitored by the PSAO 24 hours per 
day while at the proposed seismic survey area during airgun operations, 
and during most periods when the Langseth is underway while the airguns 
are not operating. However, PAM may not be possible if damage occurs to 
the array or back-up systems during operations. The primary PAM 
streamer on the Langseth is a digital hydrophone streamer. Should the 
digital streamer fail, back-up systems should include an analog spare 
streamer and a hull-mounted hydrophone. One PSAO will monitor the 
acoustic detection system by listening to the signals from two channels 
via headphones and/or speakers and watching the real-time 
spectrographic display for frequency ranges produced by cetaceans. The 
PSAO monitoring the acoustical data will be on shift for one to six 
hours at a time. All PSOs are expected to rotate through the PAM 
position, although the expert PSAO will be on PAM duty more frequently.
    When a vocalization is detected while visual observations (during 
daylight) are in progress, the PSAO will contact the PSVO immediately, 
to alert him/her to the presence of cetaceans (if they have not already 
been seen), and to allow a power-down or shut-down to be initiated, if 
required. When bearings (primary and mirror-image) to calling 
cetacean(s) are determined, the bearings will be related to the PSVO(s) 
to help him/her sight the calling animal. During non-daylight hours, 
when a cetacean is detected by acoustic monitoring and may be close to 
the source vessel, the Langseth crew will be notified immediately so 
that the proper mitigation measure may be implemented.
    The information regarding the call will be entered into a database. 
Data entry will include an acoustic encounter identification number, 
whether it was linked with a visual sighting, date, time when first and 
last heard and whenever any additional information was recorded, 
position and water depth when first detected, bearing if determinable, 
species or species group (e.g., unidentified dolphin, sperm whale), 
types and nature of sounds heard (e.g., clicks, continuous, sporadic, 
whistles, creaks, burst pulses, strength of signal, etc.), and any 
other notable information. The acoustic detection can also be recorded 
for further analysis.

PSO Data and Documentation

    PSVOs will record data to estimate the numbers of marine mammals 
exposed to various received sound levels and to document apparent 
disturbance reactions or lack thereof. Data will be used to estimate 
numbers of animals potentially `taken' by harassment (as defined in the 
MMPA). They will also provide information needed to order a power-down 
or shut-down of the airguns when a marine mammal is within or near the 
exclusion zone. Observations will also be made during daytime periods 
when the Langseth is underway without seismic operations. There will 
also be opportunities to collect baseline

[[Page 58281]]

biological data during the transits to, from, and through the study 
area.
    When a sighting is made, the following information about the 
sighting will be recorded:
    1. Species, group size, age/size/sex categories (if determinable), 
behavior when first sighted and after initial sighting, heading (if 
consistent), bearing and distance from seismic vessel, sighting cue, 
apparent reaction to the airguns or vessel (e.g., none, avoidance, 
approach, paralleling, etc.), and behavioral pace.
    2. Time, location, heading, speed, activity of the vessel, sea 
state, visibility, and sun glare.
    The data listed under (2) will also be recorded at the start and 
end of each observation watch, and during a watch whenever there is a 
change in one or more of the variables.
    All observations and ramp-ups, power-downs or shut-downs will be 
recorded in a standardized format. The PSOs will record this 
information onto datasheets. During periods between watches and periods 
when operations are suspended, those data will be entered into a laptop 
computer running a custom computer database. The accuracy of the data 
entry will be verified by computerized data validity checks as the data 
are entered and by subsequent manual checking of the database. These 
procedures will allow initial summaries of data to be prepared during 
and shortly after the field program, and will facilitate transfer of 
the data to statistical, graphical, and other programs for further 
processing and archiving. Quality control of the data will be 
facilitated by (a) The start-of survey training session; (b) subsequent 
supervision by the onboard lead PSO; and (c) ongoing data checks during 
the seismic survey.
    Results from the vessel-based observations will provide:
    1. The basis for real-time mitigation (airgun power-down or shut-
down).
    2. Information needed to estimate the number of marine mammals 
potentially taken by harassment, which must be reported to NMFS.
    3. Data on the occurrence, distribution, and activities of marine 
mammals in the area where the seismic study is conducted.
    4. Information to compare the distance and distribution of marine 
mammals relative to the source vessel at times with and without seismic 
activity.
    5. Data on the behavior and movement patterns of marine mammals 
seen at times with and without seismic activity.
    Throughout the seismic survey, PSOs will prepare a report each day 
or at such other intervals as required by NMFS, USFWS, the U.S. Army 
Corps of Engineers, California State Lands Commission, California 
Coastal Commission, or PG&E, summarizing the recent results of the 
monitoring program. The reports will summarize the species and numbers 
of marine mammals sighted. These reports will be provided to NMFS as 
well as PG&E, L-DEO, and NSF.
    In addition to the vessel-based monitoring, L-DEO and PG&E will 
submit reports outlining the monitoring results of the aerial survey 
for large cetaceans, the aerial survey for harbor porpoises and other 
small cetaceans, and any marine mammals stranding response activities.
    L-DEO and PG&E will submit a comprehensive report to NMFS and NSF 
within 90 days after the end of the cruise. The report will describe 
the operations that were conducted and sightings of marine mammals near 
the operations. The report will provide full documentation of methods, 
results, and interpretation pertaining to all monitoring. The 90-day 
report will summarize the dates and locations of seismic operations, 
and all marine mammal sightings (i.e., dates, times, locations, 
activities, associated seismic survey activities, and associated PAM 
detections). The report will 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 
detectability of marine mammals including sea state, number of PSOs, 
and fog/glare;
     Species composition, occurrence, and distribution of 
marine mammals sightings including date, water depth, numbers, age/
size/gender, and group sizes; and analyses of the effects of seismic 
operations;
     Sighting rates of marine mammals during periods with and 
without airgun activities (and other variables that could affect 
detectability);
     Initial sighting distances versus airgun activity state;
     Closes point of approach versus airgun activity state;
     Observed behaviors and types of movements versus airgun 
activity state;
     Numbers of sightings/individuals seen versus airgun 
activity state; and
     Distribution around the source vessel versus airgun 
activity state.
    The report will also include estimates of the number and nature of 
exposures that could result in ``takes'' of marine mammals by 
harassment or in other ways. After the report is considered final, it 
will be publicly available on the NMFS and NSF Web sites at: https://www.nmfs.noaa.gov/pr/permits/incidental.htm#iha and https://www.nsf.gov/geo/oce/encomp/index.jsp.

Estimated Take by Incidental Harassment

    Except with respect to certain activities not pertinent here, the 
MMPA defines ``harassment'' as: Any act of pursuit, torment, or 
annoyance which (i) has the potential to injure a marine mammal or 
marine mammal stock in the wild [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 [Level B harassment].
    Level B harassment is anticipated and proposed to be authorized as 
a result of the proposed marine seismic survey off the central coast of 
California. Acoustic stimuli (i.e., increased underwater sound) 
generated during the operation of the seismic airgun array are expected 
to result in the behavioral disturbance of some marine mammals, and 
potentially the temporary displacement of some of the Morro Bay stock 
of harbor porpoises from their preferred, or core, habitat area. There 
is no evidence that the planned activities could result in injury, 
serious injury, or mortality for which L-DEO and PG&E seeks the IHA. 
The required mitigation and monitoring measures will minimize any 
potential risk for injury, serious injury, or mortality.
    The following sections describe L-DEO and PG&E's methods to 
estimate take by incidental harassment and present the applicant's 
estimates of the numbers of marine mammals that could be affected 
during the proposed seismic program along the central coast of 
California. The estimates are based on a consideration of the number of 
marine mammals that could be harassed by seismic operations with the 18 
airgun array to be used. The size of the proposed 3D seismic survey 
area in 2012 is approximately 740.52 km\2\ (285.9 nmi\2\) and located 
adjacent to the coastline and extending from 11 to 21 km (5.9 to 11.3 
nmi) offshore, as depicted in Figure 2 of the IHA application.
    L-DEO and PG&E assume that, during simultaneous operations of the 
airgun array and the other sources, any marine mammals close enough to 
be affected by the multibeam echosounder and sub-

[[Page 58282]]

bottom profiler would already be affected by the airguns. However, 
whether or not the airguns are operating simultaneously with the other 
sources, marine mammals are expected to exhibit no more than short-term 
and inconsequential responses to the multibeam echosounder and sub-
bottom profiler given their characteristics (e.g., narrow, downward-
directed beam) and other considerations described previously. Such 
reactions are not considered to constitute ``taking'' (NMFS, 2001). 
Therefore, L-DEO and PG&E provide no additional allowance for animals 
that could be affected by sound sources other than airguns.
    Density estimates are based on the best available peer-reviewed 
scientific data, specifically, the NMFS online marine mammal database 
(Barlow et al., 2009). These data are supplemented with non-published 
survey data obtained from the proposed project area during an earlier 
low-energy 3D survey (Padre Associates, Inc., 2011b). The low-energy 3D 
seismic surveys were conducted on 76 days between October 24, 2010 and 
February 5, 2011. The principal source of density information is the 
Strategic Environmental Research and Development Program (SERDP)-SDSS 
Marine Animal Model Mapper on the Ocean Biogeographic Information 
System Spatial Ecological Analysis of Megavertebrate Populations (OBIS-
SEAMAP) Web site (Barlow et al., 2009), which was recommended by NMFS 
staff at the Southwest Regional Office. A second density dataset was 
prepared by Padre Associates, Inc. (2011b) based on marine mammal 
sightings recorded during a seismic survey conducted between October, 
2010 and February, 2011. The Padre Associates, Inc. dataset is from the 
southern portion of the proposed survey area, and contained densities 
for marine mammal species for which data were sparse or absent from the 
NOAA database.
    The Padre Associates, Inc. dataset was compiled from a series of 
daily marine mammal monitoring reports, and the data were not 
originally collected for the purposes of developing density estimates. 
Further, all survey data are subject to detectability and availability 
biases. Detectability bias is associated with diminishing sightability 
of marine mammals with increasing lateral distances from the survey 
trackline ([fnof][0]). Availability bias is due to the fact that not 
all marine mammals are at the surface at all times, and, as such, there 
is less than 100 percent probability of detecting animals along the 
survey trackline [fnof](0), and it is measured by g(0).
    Within Table 3 (Tables 7 and 8 of the IHA application), marine 
mammal densities were calculated based on available density or survey 
data. PG&E and the NMFS Office of Protected Resources worked with the 
NMFS Southwest Fisheries Science Center (SWFSC) and Southwest Regional 
Office to identify the preferred method of acquiring density data was 
the SERDP sponsored by the Department of Defense (DOD) with mapping 
provided by OBIS-SEAMAP. Within the mapping program density data are 
available by strata or density models (indicated with a superscripted 
lower case ``a'' (\a\).
    For density models, the Geographic Information Systems (GIS) 
shapefile of the proposed project area (tracklines [referred to as 
``race track'' in the IHA application] with the 160 dB buffer zone) was 
uploaded into the program and densities for the ensonified area were 
calculated using available NMFS data within the uploaded project area. 
Density data calculated using this method was indicated with a 
superscript ``1'' (\1\). All densities calculated using this model were 
from summer data (defined as July to December). For density data 
indicated with a superscript ``2'' (\2\), stratum density data was used 
within the same SERDP marine mammal mapper; however, a different layer 
of the mapping program were utilized. The stratum layer provides 
limited density data for the region the species occurs within. This 
density number within the stratum layer is static for the region.
    For Padre Associates, Inc. densities indicated with an uppercase 
superscript ``B'' (\B\), data were acquired between October, 2010 and 
February, 2011 during seismic surveys. The data used to acquire the 
densities were collected from daily monitoring logs where species were 
observed and recorded when navigating survey tracklines and transiting 
to and from the survey area. The density was calculated based on a 305 
m (1,000 ft) visibility in each direction of the observer/vessel by the 
distance of tracklines or transits conducted during the survey period. 
These density data were used as supplemental information based on the 
lack of density models of species within the SERDP.
    For harbor porpoise density data indicated with superscripted ``c'' 
(\c\), NMFS SWFSC staff worked with NMFS Office of Protected Resources 
to construct fine-scale density estimates based on aerial surveys of 
the central coast conducted between 2002 and 2011. NMFS SWFSC provided 
latitude coordinates of density changes for the harbor porpoise were 
inserted into GIS to delineate the associated polygon within the 
project survey boxes. The corrected density data were extracted for the 
project site within the 160 dB ensonified areas of Survey Boxes 2 and 
4. The density data are variable based on the location within the 
project site, with the San Luis Bay having the highest density. Because 
of the variable densities used to extract the estimated number of 
individuals within the project site, the densities within Tables 7 and 
8 of the IHA application are broad categorical densities for their 
corresponding survey box. Additionally, the offshore portion (greater 
than 92 m [301.8 ft]) of the harbor porpoise density is a stock-wide 
density used in Caretta et al. (2009) and also within the data provided 
by the NMFS SWFSC. An additional figure illustrating the fine scale 
densities used to calculate the take numbers is available in Appendix B 
of the IHA application.

      Table 3--Estimated Densities of Marine Mammal Species in the Proposed Survey Off the Central Coast of
                                     California, November to December, 2012
----------------------------------------------------------------------------------------------------------------
                                    NOAA density \a\ (/km\2\)      Padre Associates, Inc. density \b\
                                 ----------------------------------------            (/km\2\)
             Species                 Box 2 minimum       Box 4 minimum   ---------------------------------------
                                     maximum mean        maximum mean           Transit            Transect
----------------------------------------------------------------------------------------------------------------
Mysticetes:
    North Pacific right whale     0.000061..........  0.000061..........  NA................  NA.
     \2\.                         0.000061..........  0.000061..........
                                  0.000061..........  0.000061..........

[[Page 58283]]

 
    Gray whale..................  NA................  NA................  0.0154............  0.0211.
                                  NA................  NA................
                                  NA................  NA................
    Humpback whale \1\..........  0.000088..........  0.00117...........  0.0028............  0.0065.
                                  0.005781..........  0.00635...........
                                  0.002349..........  0.003243..........
    Minke whale \2\.............  0.000276..........  0.000276..........  0.0007............  0.0008.
                                  0.000276..........  0.000276..........
                                  0.000276..........  0.000276..........
    Sei whale \2\...............  0.000086..........  0.000086..........  NA................  NA.
                                  0.000086..........  0.000086..........
                                  0.000086..........  0.000086..........
    Fin whale \1\...............  0.000142..........  0.00239...........  NA................  NA.
                                  0.01083...........  0.0113............
                                  0.004385..........  0.006177..........
    Blue whale \1\..............  0.0001............  0.001254..........  NA................  NA.
                                  0.006603..........  0.006777..........
                                  0.002652..........  0.003579..........
Odontocetes:
    Sperm whale \1\.............  0.000009..........  0.000187..........  NA................  NA.
                                  0.000723..........  0.000768..........
                                  0.000297..........  0.000436..........
    Kogia spp. (Pygmy and dwarf   0.001083..........  0.001083..........  NA................  NA.
     sperm whale) \2\.            0.001083..........  0.001083..........
                                  0.001083..........  0.001083..........
    Baird's beaked whale \1\....  0.000016..........  0.000244..........  NA................  NA.
                                  0.001148..........  0.001148..........
                                  0.000467..........  0.000638..........
    Small (Mesoplodon and         0.000042..........  0.000813..........  NA................  NA.
     Cuvier's) beaked whale \1c\. 0.003347..........  0.003422..........
                                  0.001363..........  0.001952..........
    Bottlenose dolphin \2\......  Coastal \4\.......  Coastal \4\.......  NA................  NA.
                                  0.361173..........  0.361173..........
                                  0.361173..........  0.361173..........
                                  0.361173..........  0.361173..........
                                  Offshore--Winter    Offshore--Winter
                                  0.000616..........  0.000616..........
                                  0.000616..........  0.000616..........
                                  0.000616..........  0.000616..........
    Striped dolphin \1\.........  0.000039..........  0.000943..........  NA................  0.0081.
                                  0.0033............  0.003448..........
                                  0.001379..........  0.002075..........
    Short-beaked common dolphin   0.01203...........  0.1612............  0.0252............  0.0836.
     \1\.                         0.8019............  0.8285............
                                  0.3252............  0.4443............
    Long-beaked common dolphin    0.018004..........  0.018004..........  NA................  NA.
     \2\.                         0.018004..........  0.018004..........
                                  0.018004..........  0.018004..........
    Pacific white-sided dolphin   0.001027..........  0.01856...........  NA................  NA.
     \1\.                         0.08342...........  0.0896............
                                  0.03364...........  0.04786...........
    Northern right whale dolphin  0.00066...........  0.0112............  NA................  NA.
     \1\.                         0.0503............  0.05254...........
                                  0.02038...........  0.02867...........
    Risso's dolphin \1\.........  0.000672..........  0.007767..........  0.0063............  0.2881.
                                  0.04279...........  0.04545...........
                                  0.001721..........  0.02316...........
    Killer whale \2\............  Summer............  Summer............  Summer NA.........  Summer NA.
                                  0.000709..........  0.000709..........
                                  0.000709..........  0.000709..........
                                  0.000709..........  0.000709..........
                                  Winter............  Winter............  Winter NA.........  Winter 0.0016.
                                  0.000246..........  0.000246..........
                                  0.000246..........  0.000246..........
                                  0.000246..........  0.000246..........
    Short-finned pilot whale \2\  0.000307..........  0.000307..........  NA................  NA.
                                  0.000307..........  0.000307..........
                                  0.000307..........  0.000307..........

[[Page 58284]]

 
    Harbor porpoise \3\.........  Morro Bay Inshore.  Morro Bay Inshore.  Morro Bay Inshore   Morro Bay Inshore
                                  0.43..............  0.43..............   0.0259.             0.0016
                                  4.17..............  1.42..............
                                  1.83..............  1.22..............
                                  Morro Bay Offshore  Morro Bay Offshore  Morro Bay Offshore  Morro Bay Offshore
                                  0.062.............  0.062.............   NA.                 NA
                                  0.062.............  0.062.............
                                  0.062.............  0.062.............
    Dall's porpoise \1\.........  0.000441..........  0.008552..........  NA................  0.0081.
                                  0.03504...........  0.0396............
                                  0.01433...........  0.0209............
Pinnipeds:
    California sea lion.........  NA................  NA................  NA................  NA.
                                  NA................  NA................
                                  NA................  NA................
    Steller sea lion............  NA................  NA................  NA................  NA.
                                  NA................  NA................
                                  0.00001...........  0.00001...........
    Guadalupe fur seal..........  NA................  NA................  NA................  NA.
                                  NA................  NA................
                                  0.00001...........  0.00001...........
    Northern fur seal...........  NA................  NA................  NA................  NA.
                                  NA................  NA................
                                  0.00001...........  0.00001...........
    Northern elephant seal......  NA................  NA................  NA................  NA.
                                  NA................  NA................
                                  0.00001...........  0.00001...........
    Pacific harbor seal.........  NA................  NA................  0.0166............  0.0089.
                                  NA................  NA................
                                  NA................  NA................
----------------------------------------------------------------------------------------------------------------
NA = Not available or not assessed.
\a\ Barlow et al. (2009) average density used in calculation.
\1\ Density data based on density models of survey area in SERDP program.
\2\ Density data based on stratums within SERDP program.
\3\ Density data from Caretta et al. (2009).
\4\ Density data based on stratums within SERDP program with only area ensonified within 1 km from shore
  calculated.
\b\ Padre Associates, Inc. (2011b) (Highest density between transit and track data used).
\c\ SERDP Marine Mammal Mapper categorizes small beaked whales as both Mesoplodon and Ziphiidae genera; whereas,
  the NMFS Stock Assessment Report has Ziphiidae genera whale as their own species assessment and combines only
  Mesoplodon species together.

    The proposed 3D survey area varies by survey box (see Table 3 or 
Table 6 of the IHA application). The anticipated area ensonified by the 
sound levels of greater than or equal to 160 dB (rms), based on the 
calculations provided by Greeneridge Scientific, Inc., is a 6.21 km 
(3.35 nmi) radius extending from each point of the survey area 
perimeter (hereafter called the buffer zone). This results in a maximum 
total area as shown in Table 3 (Table 6 and depicted on Figures 11 to 
12 of the IHA application). The approach for estimating take by Level B 
harassment (described in more detail below) was taken because closely 
spaced survey tracklines and large cross-track distances of the greater 
than or equal to 160 dB (rms) radii result in repeated exposure of the 
same area of water. Excessive amounts of repeated exposure probably 
results in an overestimate of the number of animals ``taken'' by Level 
B harassment.

     Table 4--Survey Areas and Survey Areas With 160 dB Buffer Zone
------------------------------------------------------------------------
                                                       Survey area with
            Survey box                 Survey area    160 dB buffer zone
                                    (km\2\ [nmi\2\])   (km\2\ [nmi\2\])
------------------------------------------------------------------------
2.................................     406.0 (118.4)     1,272.3 (370.9)
4.................................      334.5 (97.5)       784.5 (228.7)
------------------------------------------------------------------------

    L-DEO and PG&E estimated the number of different individuals that 
may be exposed to airgun sounds with received levels greater than or 
equal to 160 dB re 1 [micro]Pa (rms) on one or more occasions by 
considering the total marine area that would be within the 160 dB 
radius around the operating airgun array on at least one occasion and 
the expected density of marine mammals. The number of possible 
exposures (including repeat exposures of the same individuals) can be 
estimated by considering the total marine area that would be within the

[[Page 58285]]

160 dB radius around the operating airguns, excluding areas of overlap. 
Some individuals may be exposed multiple times since the survey 
tracklines are spaced close together, however, it is unlikely that a 
particular animal would stay in the area during the entire survey.
    The number of different individuals potentially exposed to received 
levels greater than or equal to 160 re 1 [micro]Pa (rms) was calculated 
by multiplying:
    (1) The expected species density (in number/km\2\), times
    (2) The anticipated area (in Survey Boxes 2 and 4 separately) to be 
ensonified to that level during airgun operations excluding overlap.
    Areas of overlap within each survey box (because of lines being 
closer together than the 160 dB radius) were combined into one 
ensonified area estimate and included only once when estimating the 
number of individuals exposed. However, the full area of each of the 
two survey boxes were separately used in the take calculations as 
described below.
    Applying the approach described above, approximately 1,237 km\2\ 
(360.7 nmi\2\) for Survey Box 2 and 784.5 km\2\ (228.7 nmi\2\) for 
Survey Box 4 would be within the 160 dB isopleth on one or more 
occasions during the survey. The take calculations within a given 
survey box do not explicitly add animals to account for the fact that 
new animals are not accounted for in the initial density snapshot and 
animals could also approach and enter the area ensonified above 160 dB; 
however, studies suggest that many marine mammals will avoid exposing 
themselves to sounds at this level, which suggests that there would not 
necessarily be a large number of new animals entering the area once the 
seismic survey started. Additionally, separate take estimates were 
calculated for each survey box, and the two survey boxes do overlap 
over a relatively large area. This approach for calculating take 
estimates considers the fact that new animals could have moved into the 
area, which means that it also considers the fact that new animals 
could have moved into the area in the time between the end of Survey 
Box 4 seismic operations and the beginning of Survey Box 2 seismic 
operations.
    L-DEO and PG&E's estimates of exposures to various sound levels 
assume that the proposed surveys will be carried out in full (i.e., 
approximately 10 and 14 days of seismic airgun operations for Survey 
Box 4 and Survey Box 2, respectively), however, the ensonified areas 
calculated using the planned number of line-kilometers have been 
increased by 25% to accommodate lines that may need to be repeated, 
equipment testing, account for repeat exposure, etc. As is typical 
during offshore ship surveys, inclement weather and equipment 
malfunctions are likely to cause delays and may limit the number of 
useful line-kilometers of seismic operations that can be undertaken.
    Table 5 (Table 7 and 8 of the IHA application) shows the estimates 
of the number of different individual marine mammals anticipated to be 
exposed to greater than or equal to 160 dB re 1 [mu]Pa (rms) during the 
seismic survey. For the species that a density was not reported (Barlow 
et al., 2009), a minimum density of (0.00001/km\2\) was used for low 
probability for chance encounters.
    The estimate of the number of individual cetaceans and pinnipeds 
that could be exposed to seismic sounds with received levels greater 
than or equal to 160 dB re 1 [mu]Pa (rms) during the proposed survey is 
2,329 and 511, respectively (2,606 and 639 with 25% contingency) (see 
Table 14 of the IHA application). That total (with 25% contingency) 
includes 83 baleen whales, with estimates of 55 gray, 7 humpback, 13 
fin, and 8 blue whales, which should represent 0.3, 0.3, 0.4, and 0.3% 
of the affected populations or stocks, respectively. In addition, 3 
dwarf/pygmy sperm whales, 5 killer whales, and 6 beaked whales, 
(including Cuvier's, Baird's, and Mesoplodon beaked whales) could be 
taken by Level B harassment during the proposed seismic survey. Most of 
the cetaceans potentially taken by Level B harassment are delphinids; 
short-beaked common, long-beaked common, Pacific white-sided, northern 
right whale, bottlenose, and Risso's dolphins, and harbor and Dall's 
porpoises are estimated to be the most common species in the area, with 
estimates of 953, 47, 100, 60, 40, 50, 1,513, and 43, which would 
represent 0.2, 0.2, 0.4 0.7, 0.1/9.6, 0.8, 74, 0.1% of the regional 
populations or stocks, respectively. The most common pinniped species 
estimated to be potentially taken by Level B harassment are California 
sea lions and Pacific harbor seals, with estimates of 597 and 34, which 
would represent 0.2 and 0.1% of the affected populations or stocks, 
respectively.

 Table 5--Estimates of the Possible Numbers of Marine Mammals Exposed to Sound Levels >=160 dB during L-DEO and
      PG&E's Proposed Seismic Surveys Off the Central Coast of California During November to December, 2012
----------------------------------------------------------------------------------------------------------------
                                            Requested take
                                         authorization [i.e.,
                                         estimated number of         Requested take       Approximate percentage
                                        individuals exposed to     authorization with       of best population
               Species                  sound levels >= 160 dB   additional 25% for Box  estimate of stock (with
                                        re 1 [mu]Pa] for Box 2     2 Box 4 (total for      additional 25%) \1\
                                        Box 4 (total for Boxes       Boxes 2 and 4)
                                               2 and 4)
----------------------------------------------------------------------------------------------------------------
Mysticetes:
    North Pacific right whale........  0......................  0......................  0 (0).
                                       0......................  0......................
                                       (0)....................  (0)....................
    Gray whale.......................  27.....................  .......................  0.2 (0.3).
                                       17.....................  34.....................
                                       (44)...................  21.....................
                                                                (55)...................
    Humpback whale...................  3......................  4......................  0.3 (0.3).
                                       3......................  3......................
                                       (6)....................  (7)....................
    Minke whale......................  0......................  0......................  0 (0.0).
                                       0......................  0......................
                                       (0)....................  (0)....................

[[Page 58286]]

 
    Fin whale........................  6......................  7......................  0.4 (0.4).
                                       5......................  6......................
                                       (11)...................  (13)...................
    Sei whale........................  0......................  0......................  0 (0).
                                       0......................  0......................
                                       (0)....................  (0)....................
    Blue whale.......................  3......................  4......................  0.2 (0.3).
                                       3......................  4......................
                                       (6)....................  (8)....................
Odontocetes:
    Sperm whale......................  0......................  0......................  0 (0).
                                       0......................  0......................
                                       (0)....................  (0)....................
    Kogia spp. (Pygmy and dwarf sperm  1......................  2......................  0.3 (0.5)--Pygmy sperm
     whale).                           1......................  1......................   whale
                                       (2)....................  (3)....................  NA--Dwarf sperm whale.
    Baird's beaked whale.............  1......................  1......................  0.2 (0.2).
                                       1......................  1......................
                                       (2)....................  (2)....................
    Small beaked whale (Cuvier's and   2......................  2......................  0.2 (0.2)--Cuvier's
     Mesoplodon beaked whale).         2......................  2......................   beaked whale
                                       (4)....................  (4)....................  0.3 (0.3)--Mesoplodon
                                                                                          beaked whale.
    Bottlenose dolphin...............  14--Coastal............  18--Coastal............  0.1 (0.1)--CA/OR/WA
                                       1--Offshore Winter.....  1 Offshore Winter......   stock
                                       17--Coastal............  21--Coastal............  9.6 (12.1)--California
                                       0--Offshore Winter.....  0--Offshore Winter.....   Coastal stock.
                                       (31--Coastal)..........  (39--Coastal)
                                       (1--Offshore Winter)...  (1--Offshore Winter)...
    Striped dolphin..................  2......................  2......................  <0.1 (<0.1).
                                       2......................  2......................
                                       (4)....................  (4)....................
    Short-beaked common dolphin......  414....................  517....................  0.2 (0.2).
                                       349....................  436....................
                                       (763)..................  (953)..................
    Long-beaked common dolphin.......  23.....................  29.....................  0.1 (0.2).
                                       14.....................  18.....................
                                       (37)...................  (47)...................
    Pacific white-sided dolphin......  43.....................  53.....................  0.3 (0.4).
                                       38.....................  47.....................
                                       (81)...................  (100)..................
    Northern right whale dolphin.....  26.....................  32.....................  0.6 (0.7).
                                       22.....................  28.....................
                                       (48)...................  (60)...................
    Risso's dolphin..................  22.....................  27.....................  <0.6 (0.8).
                                       18.....................  23.....................
                                       (40)...................  (50)...................
    Killer whale.....................  2......................  1.2 (2.1)--Eastern
                                       1......................   North Pacific Offshore
                                       (3)....................   stock.
                                       3......................  0.9 (1.5)--Eastern
                                       2......................   North Pacific
                                       (5)....................   Transient stock.
                                                                0.9 (1.4)--West Coast
                                                                 Transient stock..
    Short-finned pilot whale.........  0......................  0......................  0.0 (0.0).
                                       0......................  0......................
                                       (0)....................  (0)....................
    Harbor porpoise..................  895....................  1,119..................  59.2 (74).
                                       315....................  394....................
                                       (1,210)................  (1,513)................
    Dall's porpoise..................  18.....................  23.....................  0.1 (0.1).
                                       16.....................  20.....................
                                       (34)...................  (43)...................
Pinnipeds:

[[Page 58287]]

 
    California sea lion..............  295....................  369....................  0.2 (0.2).
                                       182....................  228....................
                                       (477)..................  (597)..................
    Steller sea lion.................  0......................  0......................  0 (0).
                                       0......................  0......................
                                       (0)....................  (0)....................
    Guadalupe fur seal...............  0......................  0......................  0 (0).
                                       0......................  0......................
                                       (0)....................  (0)....................
    Northern fur seal................  0......................  0......................  0 (0).
                                       0......................  0......................
                                       (0)....................  (0)....................
    Northern elephant seal...........  0......................  0......................  (0).
                                       0......................  0......................
                                       (0)....................  (0)....................
    Pacific harbor seal..............  21.....................  26.....................  0.1 (0.1]).
                                       13.....................  16.....................
                                       (34)...................  (42)...................
----------------------------------------------------------------------------------------------------------------
NA = Not available or not assessed.
\1\ Stock sizes are best populations from NMFS Stock Assessment Reports (see Table 2 in above).

Encouraging and Coordinating Research

    L-DEO and PG&E will cooperate with external entities (i.e., 
agencies, universities, non-governmental organizations) to manage, 
understand, and communicate information about environmental impacts 
related to the seismic activities provided an acceptable methodology 
and business relationship can be agreed upon. PG&E is currently working 
with a number of agencies and groups to implement monitoring programs 
to address potential short-term and long-term effects on marine 
resources within the project area. These study programs include:
     Monitoring activities associated with the California 
Department of Fish and Game Scientific Collection Permit for Point 
Buchon Marine Protected Area;
     Nature Conservancy Remotely Operated Vehicle (ROV) 
Monitoring Program;
     California Collaborative Fisheries Research Program;

Negligible Impact Determination

    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.'' In making a negligible impact determination, 
NMFS evaluated factors such as:
    (1) The number of anticipated injuries, serious injuries, or 
mortalities;
    (2) The number, nature, and intensity, and duration of Level B 
harassment (all relatively limited); and
    (3) The context in which the takes occur (i.e., impacts to areas of 
significance, impacts to local populations, and cumulative impacts when 
taking into account successive/contemporaneous actions when added to 
baseline data);
    (4) The status of stock or species of marine mammals (i.e., 
depleted, not depleted, decreasing, increasing, stable, impact relative 
to the size of the population);
    (5) Impacts on habitat affecting rates of recruitment/survival; and
    (6) The effectiveness of monitoring and mitigation measures.
    As described above and based on the following factors, the 
specified activities associated with the marine seismic survey are not 
likely to cause PTS, or other non-auditory injury, serious injury, or 
death. The factors include:
    (1) The likelihood that, given sufficient notice through relatively 
slow ship speed, marine mammals are expected to move away from a noise 
source that is annoying prior to its becoming potentially injurious;
    (2) The potential for temporary or permanent hearing impairment is 
relatively low and would likely be avoided through the implementation 
of the power-down and shut-down measures;
    (3) The Morro Bay Stock of Harbor Porpoise Monitoring Plan and 
Stranding Response Plan will provide real-time data (via aerial surveys 
and beach monitors) allowing for the early detection of marine mammal 
(and especially harbor porpoise) behaviors that may indicate an 
increased potential for stranding. This information will be used to 
modify, in real-time, any aspect of the activity that could contribute 
to a marine mammal stranding (e.g., suspension of seismic airgun 
operations) and the additional evaluation of the situation that will 
minimize the likelihood of injury or death resulting from the proposed 
activity;
    (4) The Morro Bay stock of Harbor Porpoise Monitoring Plan will 
also use a combination of aerial and acoustic data to detect whether 
moderate to large numbers of harbor porpoises have been displaced from 
their core habitat which could result in serious energetic impacts to 
individuals if it continued longer than a short time. This information 
will be used to modify, in real-time, any aspect of the activity (e.g., 
suspension of seismic airgun operations) that could result in impacts 
of a more serious nature (e.g., mortality);
    No injuries, serious injuries, or mortalities are anticipated to 
occur as a result of the L-DEO and PG&E's

[[Page 58288]]

planned marine seismic surveys, and none are proposed to be authorized 
by NMFS. Table 5 of this document outlines the number of requested 
Level B harassment takes that are anticipated as a result of these 
activities. Due to the nature, degree, and context of Level B 
(behavioral) harassment anticipated and described (see ``Potential 
Effects on Marine Mammals'' section above) in this notice, the activity 
is not expected to impact rates of annual recruitment or survival for 
any affected species or stock, particularly given the NMFS and the 
applicant's proposal to implement a rigorous mitigation, monitoring, 
and stranding response plans to minimize impacts to the Morro Bay stock 
of harbor porpoise.
    The proposed seismic operations will occur throughout a large 
portion of the range of the Morro Bay stock of harbor porpoises (i.e., 
Point Sur to Point Conception, California), and cover much of the core 
range and optimal habitat for this stock for the duration of the 
seismic survey. Sighting rates outside of the operational area are much 
lower, indicating sub-optimal habitat. Studies have shown that harbor 
porpoises are sensitive to underwater sound and will move long 
distances away from a loud sound source; and the Morro Bay stock may be 
forced to move to sub-optimal habitat at the ends of (North or South), 
or outside their normal range for days to weeks, which may affect 
foraging success which could in turn have energetic impacts that effect 
reproduction or survival. This is a coastal species that is primarily 
found in shallow water within the approximate 100 m (328 ft) isobath 
and does not move offshore as this is not suitable habitat, and the 
seismic airgun operations will ensonify a large area that reaches from 
land to offshore past where harbor porpoises are typically found. This 
small-bodied species has a high metabolic rate (Spitz et al., 2010) 
requiring regular caloric intake to maintain fitness and health; 
therefore, there is a potential for adverse health effects if an animal 
were forced into an area offering sub-optimal habitat for an extended 
period of time.
    The November to December, 2012, timeframe of the seismic operations 
will avoid the peak of their breeding season and after the first few 
months that are critical to nursing mothers and dependent calves. The 
phased approach, as suggested by NMFS and agreed to by the applicant, 
of conducting seismic operations within the survey boxes (i.e., Survey 
Box 4 first, Survey Box 2 second in 2012) over multiple years (i.e., 
Survey Box 1 planned for 2013) has significantly reduced the 
anticipated energetic impacts within a given year by spreading them 
over two years. Further, the required monitoring plans will allow us to 
assess the degree to which, and in part the amount of time, harbor 
porpoises may be displaced from their core habitat (and potentially 
crowded into sub-optimal habitat and adjust, in real time L-DEO and 
PG&E's activity to minimize the likelihood of population level effects. 
Silent periods (i.e., no active use of airguns) between conducting 
seismic operations for Survey Box 4 and Survey Box 2 should allow any 
displaced animals to return to optimal habitat for foraging and feeding 
that are necessary for reproduction, nursing, and survivorship; and the 
required monitoring will allow NMFS to detect whether or not this 
happens and make a decision about whether PG&E may conduct the second 
survey (i.e., Survey Box 2) this year.
    For the other marine mammal species that may occur within the 
proposed action area, there are no known designated or important 
feeding and/or reproductive areas. The gray whale, which has an annual 
migration route along the coastline, has the potential to occur in the 
action area during the proposed seismic survey. The southward migration 
along the West Coast of North America from summer feeding areas in the 
north generally occurs from November/December through February, while 
the northward migration from winter breeding areas in the south 
generally occurs from mid-February through May (with a peak in March). 
During the southward migration, animals do not approach as close to the 
coastline and the area of the seismic surveys than they would during 
the northward migration (especially cows and calves). The proposed end 
of the seismic survey is designed to coincide with the approximate 
start of the peak of the annual southward gray whale migration 
(December 15, 2012), therefore most of the animals will start traveling 
through after the seismic operations have concluded. Many animals 
perform vital functions, such as feeding, resting, traveling, and 
socializing, on a diel cycle (i.e., 24 hr cycle). Behavioral reactions 
to noise exposure (such as disruption of critical life functions, 
displacement, or avoidance of important habitat) are more likely to be 
significant if they last more than one diel cycle or recur on 
subsequent days (Southall et al., 2007). While seismic operations are 
anticipated to occur on consecutive days, they are broken into two 
sections of approximately 10 and 14 days, and the monitoring and 
mitigation is designed such that if serious impacts of a nature 
expected to have adverse effects on reproduction or survival were 
detected and thought to be occurring to a significant number of 
individuals, the second portion of the survey would proceed. 
Additionally, the seismic survey will be increasing sound levels in the 
marine environment in a relatively small area surrounding the vessel 
(compared to the range of the animals), which is constantly travelling 
over distances, and some animals may only be exposed to and harassed by 
sound for shorter less than day.
    Of the 36 marine mammal species under NMFS jurisdiction that are 
known to or likely to occur in the study area, eight are listed as 
threatened or endangered under the ESA: North Pacific right, humpback, 
sei, fin, blue, and sperm whales as well as Steller sea lions and 
Guadalupe fur seals. These species are also considered depleted under 
the MMPA. Of these ESA-listed species, incidental take has been 
requested to be authorized for humpback, fin, blue, and sperm whales. 
There is generally insufficient data to determine population trends for 
the other depleted species in the study area. To protect these animals 
(and other marine mammals in the study area), L-DEO and PG&E must cease 
or reduce airgun operations if animals enter designated zones. No 
injury, serious injury, or mortality is expected to occur and due to 
the nature, degree, and context of the Level B harassment anticipated, 
the activity is not expected to impact rates of recruitment or 
survival.
    As mentioned previously, NMFS estimates that 25 species of marine 
mammals under its jurisdiction could be potentially affected by Level B 
harassment over the course of the IHA. The population estimates for the 
marine mammal species that may be taken by Level B harassment were 
provided in Table 5 of this document.
    NMFS's practice has been to apply the 160 dB re 1 [micro]Pa (rms) 
received level threshold for underwater impulse sound levels to 
determine whether take by Level B harassment occurs. Southall et al. 
(2007) provide a severity scale for ranking observed behavioral 
responses of both free-ranging marine mammals and laboratory subjects 
to various types of anthropogenic sound (see Table 4 in Southall et al. 
[2007]).
    NMFS has preliminarily determined, provided that the aforementioned 
mitigation and monitoring measures are implemented, that for species 
other than the Morro Bay stock of harbor porpoise, the impact of 
conducting a marine

[[Page 58289]]

seismic survey off the central coast of California, November to 
December, 2012, may result, at worst, in a modification in behavior 
and/or low-level physiological effects (Level B harassment) of certain 
species of marine mammals.
    While behavioral modifications, including temporarily vacating the 
area during the operation of the airgun(s), may be made by these 
species to avoid the resultant acoustic disturbance, the availability 
of alternate areas within these areas for species other than the Morro 
Bay stock of harbor porpoises and the short and sporadic duration of 
the research activities, have led NMFS to preliminary determine that 
the taking by Level B harassment from the specified activity will have 
a negligible impact on the affected species in the specified geographic 
region. Although NMFS anticipates the potential for more serious 
impacts to harbor porpoises, as described above, NMFS believes that the 
reduced length of the seismic survey (accomplished through the 
splitting of the originally planned survey over a two year period), the 
requirement to implement mitigation measures (e.g., shut-down of 
seismic operations), and the inclusion of the comprehensive monitoring 
and stranding response plans, will reduce the amount and severity of 
the harassment from the activity to the degree that it will have a 
negligible impact on the Morro Bay stock of harbor porpoise.

Impact on Availability of Affected Species or Stock for Taking for 
Subsistence Uses

    Section 101(a)(5)(D) of the MMPA also requires NMFS to determine 
that the authorization will not have an unmitigable adverse effect on 
the availability of marine mammal species or stocks for subsistence 
use. There are no relevant subsistence uses of marine mammals in the 
study area (off the central coast of California) that implicate MMPA 
section 101(a)(5)(D).

Endangered Species Act

    Of the species of marine mammals that may occur in the proposed 
survey area, several are listed as endangered under the ESA, including 
the North Pacific right, humpback, sei, fin, blue, and sperm whales. 
Two pinniped species, the Guadalupe fur seal and eastern stock of 
Steller sea lion are listed as threatened under the ESA. L-DEO and PG&E 
did not request take of endangered North Pacific right whales due to 
the low likelihood of encountering this species during the cruise. 
Under section 7 of the ESA, NSF has initiated formal consultation with 
the NMFS, Office of Protected Resources, Endangered Species Act 
Interagency Cooperation Division, on this proposed seismic survey. 
NMFS's Office of Protected Resources, Permits and Conservation 
Division, has initiated formal consultation under section 7 of the ESA 
with NMFS's Office of Protected Resources, Endangered Species Act 
Interagency Cooperation Division, to obtain a Biological Opinion 
evaluating the effects of issuing the IHA on threatened and endangered 
marine mammals and, if appropriate, authorizing incidental take. NMFS 
will conclude formal section 7 consultation prior to making a 
determination on whether or not to issue the IHA. If the IHA is issued, 
NSF and L-DEO and PG&E, in addition to the mitigation and monitoring 
requirements included in the IHA, will be required to comply with the 
Terms and Conditions of the Incidental Take Statement corresponding to 
NMFS's Biological Opinion issued to both NSF and NMFS's Office of 
Protected Resources.

National Environmental Policy Act

    With L-DEO and PG&E's complete application, NSF provided NMFS a 
draft ``Environmental Assessment Pursuant to the National Environmental 
Policy Act, 42 U.S.C. 4321 et seq. Marine Seismic Survey in the Pacific 
Ocean off Central California, 2012,'' which incorporates a draft 
``Environmental Assessment of Marine Geophysical Surveys by the R/V 
Marcus G. Langseth for the Central Coastal California Seismic Imaging 
Project,'' prepared by Padre Associates, Inc. on behalf of NSF, L-DEO, 
and PG&E. The EA analyzes the direct, indirect, and cumulative 
environmental impacts of the proposed specified activities on marine 
mammals including those listed as threatened or endangered under the 
ESA. Prior to making a final decision on the IHA application, NMFS will 
either prepare an independent EA, or, after review and evaluation of 
the NSF EA for consistency with the regulations published by the 
Council of Environmental Quality (CEQ) and NOAA Administrative Order 
216-6, Environmental Review Procedures for Implementing the National 
Environmental Policy Act, adopt the NSF EA and make a decision of 
whether or not to issue a Finding of No Significant Impact (FONSI).

Proposed Authorization

    NMFS proposes to issue an IHA to PG&E for conducting a marine 
seismic survey off the central coast of California, provided the 
previously mentioned mitigation, monitoring, and reporting requirements 
are incorporated. The duration of the IHA would not exceed one year 
from the date of its issuance.

Information Solicited

    NMFS requests interested persons to submit comments and information 
concerning this proposed project and NMFS's preliminary determination 
of issuing an IHA (see ADDRESSES). Concurrent with the publication of 
this notice in the Federal Register, NMFS is forwarding copies of this 
application to the Marine Mammal Commission and its Committee of 
Scientific Advisors.

    Dated: September 13, 2012.
Helen M. Golde,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2012-22999 Filed 9-14-12; 11:15 am]
BILLING CODE 3510-22-P