[Federal Register Volume 78, Number 108 (Wednesday, June 5, 2013)]
[Notices]
[Pages 33811-33836]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-13280]


-----------------------------------------------------------------------

DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XC624


Takes of Marine Mammals Incidental to Specified Activities; Low-
Energy Marine Geophysical Survey in the Tropical Western Pacific Ocean, 
September to October 2013

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

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

-----------------------------------------------------------------------

SUMMARY: NMFS has received an application from the Scripps Institution 
of Oceanography (SIO), a part of the University of California at San 
Diego, for an Incidental Harassment Authorization (IHA) to take marine 
mammals, by harassment, incidental to conducting a low-energy marine 
geophysical (seismic) survey in the tropical western Pacific Ocean, 
September to October 2013. Pursuant to the Marine Mammal Protection Act 
(MMPA), NMFS is requesting comments on its proposal to issue an IHA to 
SIO to incidentally harass, by Level B harassment only, 26 species of 
marine mammals during the specified activity.

DATES: Comments and information must be received no later than July 5, 
2013.

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 [email protected]. 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 http://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: http://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications.
    The National Science Foundation (NSF) and SIO have provided a 
``Draft Environmental Analysis of a Low-Energy Marine Geophysical 
Survey by the R/V Roger Revelle in the Tropical Western Pacific Ocean, 
September-October 2013'' (EA), prepared by LGL Ltd., Environmental 
Research Associates, on behalf of NSF and SIO, which is also available 
at the same Internet address. Documents cited in this notice may be 
viewed, by

[[Page 33812]]

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 April 5, 2013, NMFS received an application from the SIO 
requesting that NMFS issue an IHA for the take, by Level B harassment 
only, of small numbers of marine mammals incidental to conducting a 
low-energy marine seismic survey in International Waters (i.e., high 
seas) and in the Exclusive Economic Zone of the Federated States of 
Micronesia (Micronesia), the Independent State of Papua New Guinea 
(Papua New Guinea), the Republic of Indonesia (Indonesia), and the 
Republic of the Philippines (Philippines) during September to October 
2013. The SIO plans to use one source vessel, the R/V Roger REVELLE 
(REVELLE), and a seismic airgun array to collect seismic data in the 
tropical western Pacific Ocean. The SIO plans to use conventional low-
energy, seismic methodology to fill gaps in equatorial Pacific data 
sets, namely the lack of high-resolution records from the eastern part 
of the Western Pacific Warm Pool to better assess controls on the 
hydrologic cycle in the Western Pacific Warm Pool, and a limited 
meridional coverage to test hypotheses related to the Plio-Pleistocene 
evolution of the Western Pacific Warm Pool. In addition to the proposed 
operations of the seismic airgun array and hydrophone streamer, SIO 
intends to operate a multibeam and 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 SIO has requested an authorization to take 
26 species of marine mammals by Level B harassment. Take is not 
expected to result from the use of the multibeam and 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 5 knots [kts]; 11.1 kilometers 
per hour [km/hr]; 6.9 miles per hour [mph]) during seismic acquisition 
within the survey, for a relatively short period of time (approximately 
26 operational days). It is likely that any marine mammal would be able 
to avoid the vessel.

Description of the Proposed Specified Activity

    SIO proposes to conduct low-energy seismic and sediment coring 
surveys at 10 sites in the tropical western Pacific Ocean in September 
to October 2013. The study sites are located between approximately 
4[deg] South to 8[deg] North and approximately 126.5 to 144.5[deg] East 
in international waters (i.e., high seas) and in the Exclusive Economic 
Zones (EEZ) of the Federated States of Micronesia (Micronesia), the 
Independent State of Papua New Guinea (Papua New Guinea), the Republic 
of Indonesia (Indonesia), and the Republic of the Philippines 
(Philippines) (see Figure 1 of the IHA application). Water depths in 
the survey area range from 450 to 3,000 meters (m) (1,476.4 to 9,842.5 
feet [ft]). The seismic surveys are scheduled to occur for 14 to 20 
hours at each of the 10 sites for approximately 26 operational days in 
September to October 2013. Some minor deviation from these dates would 
be possible, depending on logistics and weather.
    The proposed surveys would fill gaps in equatorial Pacific data 
sets, namely the lack of high-resolution records from the eastern part 
of the Western Pacific Warm Pool to better assess the controls on the 
hydrologic cycle in the Western Pacific Warm Pool, and a limited 
meridional coverage to test hypotheses related to the Plio-Pleistocene 
evolution of the Western Pacific Warm Pool. To achieve the project's 
goals, the Principal Investigators, Drs. Y. Rosenthal and G. Mountain 
of Rutgers University propose to collect low-energy, high-resolution 
multi-channel seismic profiles and sediment cores in the heart of the 
Western Pacific Warm Pool. Survey data would also be included in a 
research proposal submitted to the Integrated Ocean Drilling Program 
(IODP) for funding consideration to extend the record of millennial 
climate variability in the western equatorial Pacific Ocean back to the 
mid-Miocene. Survey and site characterization data would assist the 
IODP in determining the viability of the sites for potential future 
drilling.
    The procedures to be used for the surveys would be similar to those 
used during previous seismic surveys by SIO and would use conventional 
seismic methodology. The proposed survey will involve one source 
vessel, the R/V Roger REVELLE (REVELLE). SIO will deploy two (each with 
a discharge volume of 45 cubic inch [in\3\] with a total volume of 90 
in\3\) Generator Injector (GI) airgun

[[Page 33813]]

array as an energy source at a tow depth of 2 m (6.6 ft). The receiving 
system will consist of one 600 m (1,968.5 ft) long hydrophone streamer. 
As the GI airguns are towed along the survey lines, the hydrophone 
streamer will receive the returning acoustic signals and transfer the 
data to the onboard processing system.
    Straight survey lines would be collected in a grid of intersecting 
lines. Seven sites would be centered in small 9 x 9 km (4.9 x 4.9 nmi) 
grids of six intersecting lines (see Figure 1 of the IHA application). 
One site warrants slightly longer lines and would be surveyed in a 
large 18 x 18 km (9.7 x 9.7 nmi) grid of six intersection lines (see 
Figure 1 of the IHA application). Finally, sites S-1a and S-1b are 
close enough that efficiency in ship use would be achieved by covering 
both with a single grid of intersecting lines in a 30 x 26 km (16.2 x 
14 nmi). Individual survey lines in this grid would be approximately 5 
to 10 km (2.7 to 5.4 nmi) apart. The total track distance of survey 
data, including turns, would be approximately 1,033 km (557.8 nmi). 
Barring re-organization because of weather considerations or results 
that develop from data analyzed as sites are completed, sites would be 
surveyed in the order summarized in Table 1 (Table 1 of the IHA 
application).
    All planned seismic data acquisition activities will be conducted 
by technicians provided by SIO with onboard assistance by the 
scientists who have proposed the study. The vessel will be self-
contained, and the crew will live aboard the vessel for the entire 
cruise.
    The planned seismic survey (e.g., equipment testing, startup, line 
changes, repeat coverage of any areas, and equipment recovery) will 
consist of approximately 1,032.9 kilometer (km) (557.7 nautical miles 
[nmi]) of transect lines (including turns) in the survey area in the 
tropical western Pacific Ocean (see Figure 1 of the IHA application). 
In addition to the operation of the airgun array, a multibeam 
echosounder and a sub-bottom profiler will also likely be operated from 
the REVELLE continuously throughout the cruise between the first and 
last survey sites. 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 SIO's estimated take calculations, 25% has been added for 
those additional operations.

 Table 1--Survey Patterns and Lengths at Each Proposed Survey Site in the Tropical Western Pacific Ocean During
                                            September to October 2013
----------------------------------------------------------------------------------------------------------------
            Survey site                        Survey pattern (km)                    Survey length (km)
----------------------------------------------------------------------------------------------------------------
WP-5...............................  9 x 9 (4.9 x 4.9 nmi)..................  82.2 (44.4 nmi)
WP-6...............................  9 x 9 (4.9 x 4.9 nmi)..................  82.2 (44.4 nmi)
S-1a, S-1b.........................  30 x 26 (16.2 x 14)....................  349.5 (188.7)
WP-3...............................  9 x 9 (4.9 x 4.9 nmi)..................  82.2 (44.4 nmi)
WP-4...............................  9 x 9 (4.9 x 4.9 nmi)..................  82.2 (44.4 nmi)
WP-2...............................  9 x 9 (4.9 x 4.9 nmi)..................  82.2 (44.4 nmi)
WP-1...............................  9 x 9 (4.9 x 4.9 nmi)..................  82.2 (44.4 nmi)
WP-7...............................  9 x 9 (4.9 x 4.9 nmi)..................  82.2 (44.4 nmi)
WP-8...............................  18 x 18 (9.7 x 9.7 nmi)................  108 (58.3 nmi)
                                                                             -----------------------------------
    Total..........................  .......................................  1,032.9 (557.7 nmi)
----------------------------------------------------------------------------------------------------------------
\1\ Sites are listed in the intended order in which surveys would be conducted.

Vessel Specifications

    The REVELLE, a research vessel owned by the U.S. Navy and operated 
by SIO of the University of California San Diego, will tow the two GI 
airgun array, as well as the hydrophone streamer, along predetermined 
lines (see Figure 1 of the IHA application). When the REVELLE is towing 
the airgun array and the relatively short hydrophone streamer, the 
turning rate of the vessel while the gear is deployed is much higher 
than the limit of 5 degrees per minute for a seismic vessel towing a 
streamer of more typical length (much greater than 1 km [0.5 nmi]), 
which is approximately 20 degrees. Thus, the maneuverability of the 
vessel is not limited much during operations with the streamer.
    The vessel has a length of 83 m (272.3 ft); a beam of 16.0 m (52.5 
ft); a maximum draft of 5.2 m (9.5 ft); and a gross tonnage of 3,180. 
The ship is powered by two 3,000 horsepower (hp) Propulsion General 
Electric motors and a 1,180 hp azimuthing jet bowthruster. The 
REVELLE's operation speed during seismic acquisition is typically 
approximately 9.3 km per hour (hr) (km/hr) (5 knots [kts]). When not 
towing seismic survey gear, the REVELLE typically cruises at 22.2 to 
23.1 km/hr (12 to 12.5 kts) and has a maximum speed of 27.8 km/hr (15 
kts). The REVELLE has an operating range of approximately 27,780 km 
(15,000 nmi) (the distance the vessel can travel without refueling).
    The vessel also has two locations as likely observation stations 
from which Protected Species Observers (PSO) will watch for marine 
mammals before and during the proposed airgun operations on the 
REVELLE. Observing stations will be at the 02 level with PSO's eye 
level approximately 10.4 m (34 ft) above sea level--one forward on the 
02 deck commanding a forward-centered, approximately 240[deg] view 
around the vessel, and one atop the aft hangar, with an aft-centered 
view that includes the radii around the airguns. The eyes on the bridge 
watch will be at a height of approximately 15 m (49 ft); PSOs will work 
on the enclosed bridge and adjoining aft steering station during any 
inclement weather. More details of the REVELLE can be found in the IHA 
application.

Acoustic Source Specifications

Seismic Airguns

    The REVELLE will deploy an airgun array, consisting of two 45 in\3\ 
GI airguns as the primary energy source and a 600 m streamer containing 
hydrophones along predetermined lines. The airgun array will have a 
firing pressure of 1,750 pounds per square inch (psi). Discharge 
intervals depend on both the ship's speed and Two Way Travel Time 
recording intervals. Seismic pulses for the GI airguns will be emitted 
at intervals of approximately 10 seconds (25 m [82 ft]). At speeds of 
approximately 11.1 km/hr, the shot intervals correspond to spacing of 
approximately will be 18.5 to 31 m (60.7

[[Page 33814]]

to 101.7 ft) during the study. During firing, a brief (approximately 
0.03 second) pulse sound is emitted; the airguns will be silent during 
the intervening periods. The dominant frequency components range from 
zero to 188 Hertz (Hz).
    The generator chamber of each GI airgun in the primary source, the 
one responsible for introducing the sound pulse into the ocean, is 45 
in\3\. The injector chamber injects air into the previously-generated 
bubble to maintain its shape, and does not introduce more sound into 
the water. The two GI airguns will be towed 8 m (26.2 ft) apart, side-
by-side, 21 m (68.9 ft) behind the REVELLE, at a depth of 2 m (6.6 ft) 
during the surveys. The total effective volume will be 90 in\3\.

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 downward-directed source levels of the airgun arrays 
used by SIO on the REVELLE do not represent actual sound levels that 
can be measured at any location in the water. Rather they represent the 
level that would be found 1 m (3.3 ft) from a hypothetical point source 
emitting the same total amount of sound as is emitted by the combined 
GI airguns. The actual received level at any location in the water near 
the GI airguns will not exceed the source level of the strongest 
individual source. In this case, that will be about 224.6 dB re 1 
[micro]Pam peak, or 229.8 dB re 1 [micro]Pam peak-to-peak. 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. Actual levels experienced by any organism more than 1 m 
from either GI airgun will be significantly lower.
    Accordingly, Lamont-Doherty Earth Observatory of Columbia 
University (L-DEO) has predicted and modeled the received sound levels 
in relation to distance and direction from the two GI airgun array. A 
detailed description of L-DEO's modeling for this survey's marine 
seismic source arrays for protected species mitigation is provided in 
the NSF/USGS PEIS. These are the nominal source levels applicable to 
downward propagation. The NSF/USGS PEIS discusses the characteristics 
of the airgun pulses. NMFS refers the reviewers to that document for 
additional information.

Predicted Sound Levels for the Airguns

    To determine exclusion zones for the airgun array to be used in the 
intermediate and deep water of the Gulf of Mexico (GOM), received sound 
levels have been modeled by L-DEO for a number of airgun 
configurations, including two 45 in\3\ GI airguns, in relation to 
distance and direction from the airguns (see Figure 2 of the IHA 
application). The model does not allow for bottom interactions, and is 
most directly applicable to deep water. Based on the modeling, 
estimates of the maximum distances from the GI airguns where sound 
levels of 180 and 160 dB re 1 [mu]Pa (rms) are predicted to be received 
in intermediate and deep water are shown in Table 2 (see Table 2 of the 
IHA application).
    Empirical data concerning the 180 and 160 dB (rms) distances were 
acquired for various airgun arrays based on measurements during the 
acoustic verification studies conducted by L-DEO in the northern GOM in 
2003 (Tolstoy et al., 2004) and 2007 to 2008 (Tolstoy et al., 2009; 
Diebold et al., 2010). Results of the 18 and 36 airgun array are not 
relevant for the two GI airguns to be used in the proposed survey. The 
empirical data for the 6, 10, 12, and 20 airgun arrays indicate that, 
for deep water, the L-DEO model tends to overestimate the received 
sound levels at a given distance (Tolstoy et al., 2004). Measurements 
were not made for the two GI airgun array in deep water; however, SIO 
proposes to use the buffer and exclusion zones predicted by L-DEO's 
model for the proposed GI airgun operations in deep water, although 
they are likely conservative given the empirical results for the other 
arrays. Using the L-DEO model, Table 1 (below) shows the distances at 
which two rms sound levels are expected to be received from the two GI 
airguns. The 180 dB re 1 [micro]Pam (rms) distances are the safety 
criteria for potential Level A harassment as specified by NMFS (2000) 
and are applicable to cetaceans. If marine mammals are detected within 
or about to enter the appropriate exclusion zone, the airguns will be 
shut-down immediately.
    Table 2 summarizes the predicted distances at which sound levels 
(160 and 180 dB [rms]) are expected to be received from the two airgun 
array operating in intermediate (100 to 1,000 m [328 to 3,280 ft]) and 
deep water (greater than 1,000 m [3,280 ft]) depths.

[[Page 33815]]



 Table 2--Predicted and Modeled (Two 45 in\3\ GI Airgun Array) Distances to Which Sound Levels >= 180 and 160 dB
 re: 1 [mu]Pa (rms) Could Be Received in Intermediate and Deep Water During the Proposed Survey in the Tropical
                                Western Pacific Ocean, September to October, 2013
----------------------------------------------------------------------------------------------------------------
                                                                           Predicted RMS radii distances (m) for
                                                                                     2 GI airgun array
   Source and total volume     Tow depth  (m)       Water depth  (m)     ---------------------------------------
                                                                                160 dB              180 dB
----------------------------------------------------------------------------------------------------------------
Two GI Airguns (90 in\3\)....               2  Intermediate (100 to       600 (1,968.5 ft)..  100 (328 ft).
                                                1,000).
Two GI Airguns (90 in\3\)....               2  Deep (> 1,000)...........  400 (1,312.3 ft)..  100 (328 ft).
----------------------------------------------------------------------------------------------------------------

    Along with the airgun operations, two additional acoustical data 
acquisition systems may be operated from the REVELLE continuously 
during the survey. The ocean floor will be mapped with the Kongsberg EM 
122 multibeam echosounder and a Knudsen Chirp 3260 sub-bottom profiler. 
This sound source would be operated continuously from the REVELLE 
throughout the cruise between the first and last survey sites.

Multibeam Echosounder

    The Revelle will operate a Kongsberg EM 122 multibeam echosounder 
to map the ocean floor. The multibeam echosounder operates at 10.5 to 
13 (usually 12) kilohertz (kHz) and is hull-mounted. The transmitting 
beamwidth is 1 or 2[deg] fore-aft and 150[deg] athwartship. The maximum 
source level is 242 dB (rms). Each `ping' consists of eight (in water 
greater than 1,000 m [3,281 ft]) or four (in water less than 1,000 m) 
successive fan-shaped transmissions, each ensonifying a sector that 
extends 1[deg] fore-aft. Continuous-wave signals increase from 2 to 15 
milliseconds (ms) in water depths up to 2,600 m (8,530 ft), and FM 
chirp signals up to 100 ms long are used in water greater than 2,600 m 
(8,530 ft). The successive transmission span an overall cross-track 
angular extent of about 150[deg], with 2 ms gaps between the pings for 
successive sectors.

Sub-Bottom Profiler

    The REVELLE will operate a Knudsen 3260 sub-bottom profiler 
continuously throughout the cruise simultaneously to map and provide 
information about the seafloor sedimentary features and bottom 
topography that is mapped simultaneously with the multibeam 
echosounder. The beam of the sub-bottom profiler is transmitted as a 
27[deg] cone, which is directed downward by a 3.5 kHz transducer in the 
hull of the REVELLE. The nominal power output is 10 kilowatt (kW), but 
the actual maximum radiated power is 3 kW or 222 dB (rms). The ping 
duration is up to 64 ms, and the ping interval is 1 second. A common 
mode of operation is a broadcast five pulses at 1 second intervals 
followed by a 5 second pause. The sub-bottom profiler is capable of 
reaching depths of 10,000 m (32,808.4 ft).
    NMFS expects that acoustic stimuli resulting from the proposed 
operation of the two GI airgun array has the potential to harass marine 
mammals. NMFS does not expect that the movement of the REVELLE, 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 5 kts; 9.3 km/hr; 5.8 mph) during seismic acquisition.

Piston Core, Gravity Core, and Multicore Description and Deployment

    The piston corer to be used on the REVELLE consists of a piston 
core with a 10 cm (in) diameter steel barrel up to approximately 18 m 
(59.1 ft) long with a 2,300 kilogram (kg) (5,070.6 pounds [lb]) weight 
and a trigger core with a 10 cm (3.9 inches [in]) diameter PVC plastic 
barrel 3 m (9.8 ft) long with a 230 kg (507.1 lb) weight, which are 
lowered concurrently into the ocean floor with 1.4 cm (0.6 in) diameter 
steel cables.
    The gravity core consists of a 6 m (19.7 ft) long core pipe that 
takes a core sample approximately 10 cm in diameter, a head weight 
approximately 45 cm (17.7 in) in diameter, and a stabilizing fin. It is 
lowered to the ocean floor with a 1.4 cm diameter steel cable at 100 m/
minute (328.1 ft/min) speed.
    The multicore consists of an outer 8-legged cone shaped frame and a 
weighted inner frame that holds up to 8 plastic core sampling tubes 80 
cm (31.5 in) long and approximately 10 cm in diameter. The outer frame 
is lowered to the bottom, and inner frame is then released to allow the 
sampling tubes to penetrate the sediment. At each of the 10 sites, one 
of each type of core would be collected.

Dates, Duration, and Specified Geographic Region

    The proposed project and survey sites are located between 
approximately 4[deg] South to 8[deg] North and approximately 126.5 to 
144.5[deg] East in International Waters and in the EEZs of Micronesia, 
Papua New Guinea, Indonesia, and the Philippines (see Figure 1 of the 
IHA application). Water depths in the survey area range from 
approximately 450 to 3,000 m (1,476.4 to 9,842.5 ft). The REVELLE is 
expected to depart from Lae, Papua New Guinea on September 6, 2013 and 
arrive at Manila, Philippines on October 1, 2013 (see Table 1 of the 
IHA application for the proposed order of survey sites. Seismic 
operations would take approximately 14 to 20 hours at each of the 10 
sites, and total transit time to the first site, between all sites, and 
from the last site would be approximately 13 days. The remainder of the 
time, approximately 6 days, would be spent collecting sediment cores at 
the 10 sites, for a total of 26 operational days. 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).

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

    The marine mammal species that potentially occur within the 
tropical western Pacific Ocean include 26 species of cetaceans and one 
sirenian. In addition to the 26 species known to occur in the tropical 
western Pacific Ocean, there are three species known to occur in 
coastal waters of the study area, these include the Australian snubfin 
dolphin (Orcaella heinsohni), Indo-Pacific humpback dolphin (Sousa 
chinensis), and the Indo-Pacific bottlenose dolphin (Tursiops aduncus). 
However, these species do not occur in in slope or deep, offshore 
waters where the proposed activities would take place. Those three 
species are not considered further in this document. No pinnipeds are 
known to occur in the proposed study area.
    The marine mammals that generally occur in the proposed action area 
belong to three taxonomic groups: mysticetes (baleen whales), 
odontocetes (toothed whales), and sirenians (the dugong).

[[Page 33816]]

Marine mammal species listed as endangered under the U.S. Endangered 
Species Act of 1973 (ESA; 16 U.S.C. 1531 et seq.), includes the 
humpback (Megaptera novaeangliae), sei (Balaenoptera borealis), fin 
(Balaenoptera physalus), blue (Balaenoptera musculus), and sperm 
(Physeter macrocephalus) whale, as well as the dugong. Of those 
endangered species, the humpback, sei, fin, blue, and sperm whale is 
likely to be encountered in the proposed survey area. The dugong 
(Dugong dugon) 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.
    Few systematic surveys have been conducted in the tropical western 
Pacific Ocean, and none have taken place during September to October. 
Borsa and Nugroho (2010) conducted 1,561 km (842.9 nmi) of surveys of 
Raja Ampat waters, including the Halmahera Sea, in West Papua during 
November to December 2007. Visser (2002 in Visser and Bonoccorso, 2003) 
conducted preliminary surveys in Kimbe Bay, New Britain, Papua New 
Guinea. Miyazaki and Wada (1978) surveyed 11,249 km (6,074 nmi) in the 
wider tropical Pacific, including Micronesia, and the waters off Papua 
New Guinea and the Solomon Islands during January to March 1976. 
Shimada and Miyashita (2001) conducted 8,721 km (4,709 nmi) of surveys 
in Micronesia, the Solomon Islands, and north of Papua New Guinea 
during February to March from 1999 to 2001. Oremus (2011) described 
4,523 km (2,442.2 nmi) of surveys in the Solomon Islands during 
November of 2009 and 2010. Dolar et al. (2006) surveyed the waters of 
the central Philippines, including the Sulu Sea, during May to June 
1994 and 1995; 2,747 km (1,483.3 nmi) were covered. In May 1996, Dolar 
et al. (1997) surveyed 825 km (445.5 nmi) in the southern Sulu Sea. 
Another survey of relevance to the proposed survey area is one that 
took place during January to April 2007 in the waters of Guam and the 
Commonwealth of the Northern Mariana Islands; a total of 11,033 km 
(5,957.3 nmi) were surveyed in the area 10 to 18[deg] North and 142 to 
148[deg] East (SRS-Parsons, 2007; Fulling et al., 2011). The 
aforementioned surveys took place in shallow coastal waters as well as 
deeper offshore waters. Records from the Ocean Biogeographic 
Information System (OBIS) database hosted by Rutgers and Duke 
University (Read et al., 2009) were also considered. Table 3 (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 September to 
October, 2013.

  Table 3--The Habitat, Regional Abundance, and Conservation Status of Marine Mammals That May Occur in or Near
                     the Proposed Seismic Survey Area in the Tropical Western Pacific Ocean
                         [See text and Table 3 in SIO's application for further details]
----------------------------------------------------------------------------------------------------------------
             Species                           Habitat              Population estimate     ESA \1\    MMPA \2\
----------------------------------------------------------------------------------------------------------------
Mysticetes:
    Humpback whale (Megaptera      Pelagic, nearshore waters, and  3,520 \3\............  EN........  D
     novaeangliae).                 banks.
    Minke whale (Balaenoptera      Pelagic and coastal...........  25,000 \4\...........  NL........  NC
     acutorostrata).
    Bryde's whale (Balaenoptera    Pelagic and coastal...........  21,000 \5\...........  NL........  NC
     edeni).
    Omura's whale (Balaenoptera    Pelagic and coastal...........  NA...................  NL........  NC
     omurai).
    Sei whale (Balaenoptera        Primarily offshore, pelagic...  7,260 to 12,620 \6\..  EN........  D
     borealis).
    Fin whale (Balaenoptera        Continental slope, pelagic....  13,620 to 18,680 \7\.  EN........  D
     physalus).
    Blue whale (Balaenoptera       Pelagic, shelf, coastal.......  NA...................  EN........  D
     musculus).
Odontocetes:
    Sperm whale (Physeter          Pelagic, deep sea.............  29,674 \8\...........  EN........  D
     macrocephalus).
    Pygmy sperm whale (Kogia       Deep waters off the shelf.....  NA...................  NL........  NC
     breviceps).
    Dwarf sperm whale (Kogia       Deep waters off the shelf.....  11,200 \9\...........  NL........  NC
     sima).
    Cuvier's beaked whale          Pelagic.......................  20,000 \9\...........  NL........  NC
     (Ziphius cavirostris).
    Longman's beaked whale         Pelagic.......................  NA...................  NL........  NC
     (Indopacetus pacificus).
    Ginkgo-toothed beaked whale    Pelagic.......................  25,300 \10\..........  NL........  NC
     (Mesoplodon ginkgodens).
    Blainville's beaked whale      Pelagic.......................  25,300 \10\..........  NL........  NC
     (Mesopldon densirostris).
    Killer whale (Orcinus orca)..  Pelagic, shelf, coastal.......  8,500 \9\............  NL........  NC
    Short-finned pilot whale.....  Pelagic, shelf coastal........  53,608 \12\..........  NL........  NC
    (Globicephala macrorhynchus).
    False killer whale (Pseudorca  Pelagic.......................  16,668 \12\..........  NL........  NC
     crassidens).
    Melon-headed whale             Pelagic.......................  45,400 \9\...........  NL........  NC
     (Peponocephala electra).
    Pygmy killer whale (Feresa     Pelagic.......................  38,900 \9\...........  NL........  NC
     attenuata).
    Risso's dolphin (Grampus       Deep water, seamounts.........  83,289 \12\..........  NL........  NC
     griseus).
    Bottlenose dolphin (Tursiops   Offshore, inshore, coastal,     168,792 \12\.........  NL........  NC
     truncatus).                    estuaries.
    Rough-toothed dolphin (Steno   Pelagic.......................  107,633 \11\.........  NL........  NC
     bredanensis).
    Fraser's dolphin               Pelagic.......................  289,300 \9\..........  NL........  NC
     (Lagenodelphis hosei).
    Striped dolphin (Stenella      Pelagic.......................  570,038 \13\.........  NL........  NC
     coeruleoalba).
    Pantropical spotted dolphin    Coastal, pelagic..............  438,064 \11\.........  NL........  NC
     (Stenella attenuata).
    Spinner dolphin (Stenella      Coastal, pelagic..............  734,837 \13\.........  NL........  NC
     longirostris).
Sirenians:
    Dugong (Dugong dugon)........  Coastal.......................  NA...................  EN........  D
----------------------------------------------------------------------------------------------------------------
NA = Not available or not assessed.

[[Page 33817]]

 
\1\ U.S. Endangered Species Act: EN = Endangered, T = Threatened, DL = Delisted, NL = Not listed.
\2\ U.S. Marine Mammal Protection Act: D = Depleted, S = Strategic, NC = Not Classified.
\3\ Oceania (Constantine et al., 2010).
\4\ Northwest Pacific and Okhotsk Sea (IWC, 2013).
\5\ Western North Pacific (IWC, 2013).
\6\ North Pacific (Tillman, 1977).
\7\ North Pacific (Ohsumi and Wada, 1974).
\8\ Western North Pacific (Whitehead, 2002).
\9\ Eastern Tropical Pacific (Wade and Gerrodette, 1993).
\10\ Eastern Tropical Pacific, all Mesoplodon spp. (Wade and Gerrodette, 1993)
\11\ Eastern Tropical Pacific (Gerrodette et al., 2008).
\12\ Western North Pacific (Miyashita, 1993).
\13\ Whitebelly stock in Eastern Tropical Pacific (Gerrodette et al., 2008).

    Refer to sections 3 and 4 of SIO'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 SIO 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. 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 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. 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

[[Page 33818]]

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. 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 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

[[Page 33819]]

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., 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, 1996a,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 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.
    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

[[Page 33820]]

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).

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 2 (above) 
presents the estimated distances from the REVELLE's airguns at which 
the received energy level (per pulse, flat-weighted) would be expected 
to be greater than or equal to 180 dB re 1 [micro]Pa (rms).
    To avoid the potential for injury, NMFS (1995, 2000) concluded that 
cetaceans should not be exposed to pulsed underwater noise at received 
levels exceeding 180 dB re 1 [mu]Pa (rms). NMFS believes that to avoid 
the potential for Level A harassment, cetaceans should not be exposed 
to pulsed underwater noise at received levels exceeding 180 dB re 1 
[mu]Pa (rms), respectively. The established 180 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.
    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).
    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

[[Page 33821]]

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 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.
    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); Madeira (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 and seismic surveys. However, evidence

[[Page 33822]]

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

    SIO 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 seconds, depending on water depth. Most of the energy in the 
sound pulses emitted by the multibeam echosounder is at frequencies 
near 12 kHz, and the maximum source level is 242 dB re 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 SIO'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 
behavior when exposed to 1 second tonal signals at frequencies similar 
to

[[Page 33823]]

those that will be emitted by the multibeam echosounder used by SIO, 
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.
    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 SIO 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

    SIO 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 
that may be used on the REVELLE 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 that may be on the REVELLE. 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 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

[[Page 33824]]

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 REVELLE 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 
REVELLE'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).
    SIO's proposed operation of one source vessel 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 REVELLE's 
slow operational speed, which is typically 5 kts. Outside of seismic 
operations, the REVELLE's cruising speed would be approximately 12 to 
12.5 kts, 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 REVELLE has a number of other advantages for 
avoiding ship strikes as compared to most commercial merchant vessels, 
including the following: the REVELLE'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 a single 600 m cable streamer. 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. In May 2011, there was one 
recorded entanglement of an olive ridley sea turtle (Lepidochelys 
olivacea) in the R/V Marcus G. Langseth's barovanes after the 
conclusion of a seismic survey off Costa Rica. There have been 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 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 851 km\2\ proposed 
project area, previously discussed in this notice. The next section 
discusses the potential impacts

[[Page 33825]]

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 SIO 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 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. They also concluded that 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

[[Page 33826]]

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 D of NSF/USGS's PEIS.
    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 
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 [micro]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

[[Page 33827]]

as 157+/-5 dB re 1 [micro]Pa, with peak levels at 175 dB re 1 
[micro]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, than 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.
    SIO 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, SIO and/or its designees have proposed 
to implement the following mitigation measures for marine mammals:
    (1) Proposed exclusion zones around the sound source;
    (2) Speed and course alterations;
    (3) Shut-down procedures; and
    (4) Ramp-up procedures.
    Proposed Exclusion Zones--SIO use radii to designate exclusion and 
buffer zones and to estimate take for marine mammals. Table 2 
(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 two GI airgun array. The 180 dB level shut-down criteria are 
applicable to cetaceans, as specified by NMFS (2000). SIO used these 
levels to establish the exclusion and buffer zones.
    Received sound levels have been modeled by L-DEO for a number of 
airgun configurations, including two 45 in\3\ Nucleus G airguns, in 
relation to distance and direction from the airguns (see Figure 2 of 
the IHA application). In addition, propagation measurements of pulses 
from two GI airguns have been reported for shallow water (approximately 
30 m [98.4 ft] depth in the GOM (Tolstoy et al., 2004). However, 
measurements were not made for the two GI airguns in deep water. The 
model does not allow for bottom interactions, and is most directly 
applicable to deep water. Based on the modeling, estimates of the 
maximum distances from the GI airguns where sound levels are predicted 
to be 180 and 160 dB re 1 [micro]Pa (rms) in deep water were determined 
(see Table 2 above).
    Empirical data concerning the 180 and 160 dB (rms) distances were 
acquired for various airgun arrays based on measurements during the 
acoustic verification studies conducted by L-DEO in the northern GOM in 
2003 (Tolstoy et al., 2004) and 2007 to 2008 (Tolstoy et al., 2009). 
Results of the 36 airgun array are not relevant for the two GI airguns 
to be used in the proposed survey. The empirical data for the 6, 10, 
12, and 20 airgun arrays indicate that, for deep water, the L-DEO model 
tends to overestimate the received sound levels at a given distance 
(Tolstoy et al., 2004). Measurements were not made for the two GI 
airgun array in deep water; however, SIO propose to use the safety 
radii predicted by L-DEO's model for the proposed GI airgun operations 
in deep water, although they are likely conservative given the 
empirical results for the other arrays. The 180 dB (rms) radii are 
shut-down criteria applicable to cetaceans and pinnipeds, respectively, 
as specified by NMFS (2000); these levels were used to establish 
exclusion zones. Therefore, the assumed 180 dB radii are 100 m for 
intermediate and deep water, respectively. If the PSO detects a marine 
mammal(s) within or about to enter the appropriate exclusion zone, the 
airguns will be shut-down immediately.
    Speed and Course Alterations--If a marine mammal is detected 
outside the exclusion zone and, based on its position and direction of 
travel (relative motion), is likely to enter the exclusion zone, 
changes of the vessel's speed and/or direct course will be considered 
if this does not compromise operational safety. This would be done if 
operationally practicable while minimizing the effect on the planned 
science objectives. 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,

[[Page 33828]]

including further course alterations and/or shut-down of the airgun(s). 
Typically, during seismic operations, the source vessel is unable to 
change speed or course, and one or more alternative mitigation measures 
will need to be implemented.
    Shut-down Procedures--SIO will shut-down the operating airgun(s) if 
a marine mammal is detected outside the exclusion zone for the 
airgun(s), and if the vessel's speed and/or course cannot be changed to 
avoid having the animal enter the exclusion zone, the seismic source 
will be shut-down before the animal is within the exclusion zone. 
Likewise, if a marine mammal is already within the exclusion zone when 
first detected, the seismic source will be shut down immediately.
    Following a shut-down, SIO will not resume airgun activity until 
the marine mammal has cleared the exclusion zone. SIO will consider the 
animal to have cleared the exclusion zone if:
     A PSO has visually observed the animal leave the exclusion 
zone, or
     A PSO has not sighted the animal within the exclusion zone 
for 15 minutes for species with shorter dive durations (i.e., small 
odontocetes), or 30 minutes for species with longer dive durations 
(i.e., mysticetes and large odontocetes, including sperm, pygmy and 
dwarf sperm, killer, and beaked whales).
    Although power-down procedures are often standard operating 
practice for seismic surveys, they are not proposed to be used during 
this planned seismic survey because powering-down from two airguns to 
one airgun would make only a small difference in the exclusion 
zone(s)--but probably not enough to allow continued one-airgun 
operations if a marine mammal came within the exclusion zone for two 
airguns.
    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 avoiding any potential injury or impairment 
of their hearing abilities. SIO will follow a ramp-up procedure when 
the airgun array begins operating after a specified period without 
airgun operations or when a shut-down shut down has exceeded that 
period. SIO proposes that, for the present cruise, this period would be 
approximately 15 minutes. L-DEO and USGS has used similar periods 
(approximately 15 minutes) during previous low-energy seismic surveys.
    Ramp-up will begin with a single GI airgun (45 in\3\). The second 
GI airgun (45 in\3\) will be added after 5 minutes. During ramp-up, the 
PSOs will monitor the exclusion zone, and if marine mammals are 
sighted, a shut-down will be implemented as though both GI airguns 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, SIO will not commence the ramp-up. 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, 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 if they choose. A 
ramp-up from a shut-down may occur at night, but only where the 
exclusion zone is small enough to be visible. SIO will not initiate a 
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.
    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.
    Based on NMFS's evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS or recommended by the public, 
NMFS has preliminarily determined that the proposed mitigation measures 
provide the means of effecting the least practicable adverse impacts on 
marine mammal species or stocks and their habitat, paying particular 
attention to rookeries, mating grounds, and areas of similar 
significance.

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

    SIO proposes 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. SIO's proposed 
``Monitoring Plan'' is described below this section. SIO 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. SIO is 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.

Vessel-Based Visual Monitoring

    PSOs 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. PSOs 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 15 minutes for this proposed cruise). When 
feasible, PSOs 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 PSO observations, the airguns will be 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.

[[Page 33829]]

    During seismic operations in the tropical western Pacific Ocean, at 
least three PSOs will be based aboard the REVELLE. SIO will appoint the 
PSOs with NMFS's concurrence. Observations will take place during 
ongoing daytime operations and nighttime ramp-ups of the airguns. 
During the majority of seismic operations, at least one PSO will be on 
duty from observation platforms (i.e., the best available vantage point 
on the source vessel) to monitor marine mammals near the seismic 
vessel. PSO(s) will be on duty in shifts no longer than 4 hours in 
duration. 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 REVELLE is a suitable platform for marine mammal observations 
and will serve as the platform from which PSOs will watch for marine 
mammals before and during seismic operations. The REVELLE has been used 
for that purpose during the routine California Cooperative Oceanic 
Fisheries Investigations (CalCOFI). Two locations are likely as 
observation stations onboard the REVELLE. Observing stations are 
located on the 02 level, with the PSO eye level at approximately 10.4 m 
(34.1 ft) above the waterline. At a forwarded-centered position on the 
02 deck, the view is approximately 240[deg]; an aft-centered view 
includes the 100 m (328.1 ft) radius area around the GI airguns. The 
PSO eye level on the bridge is approximately 15 m (49.2 ft) above sea 
level. Standard equipment for PSOs will be reticule binoculars and 
optical range finders. At night, night-vision equipment will be 
available. The PSOs will be in communication with ship's officers on 
the bridge and scientists in the vessel's operations laboratory, so 
they can advise promptly of the need for avoidance maneuvers or seismic 
source shut-down. Observing stations will be at the 02 level with PSO's 
eye level approximately 10.4 m (34 ft) above sea level--one forward on 
the 02 deck commanding a forward-centered, approximately 240[deg] view 
around the vessel, and one atop the aft hangar, with an aft-centered 
view that includes the radii around the airguns. The eyes on the bridge 
watch will be at a height of approximately 15 m (49 ft); PSOs will work 
on the enclosed bridge and adjoining aft steering station during any 
inclement weather. During daytime, the PSO(s) will scan the area around 
the vessel systematically with reticle binoculars (e.g., 7 x 50 
Fujinon), Big-eye binoculars (e.g., 25 x 150), optical range-finders 
(to assist with distance estimation), and the naked eye. At night, 
night-vision equipment will be available. The optical range-finders are 
useful in training observers to estimate distances visually, but are 
generally not useful in measuring distances to animals directly. 
Estimating distances is done primarily with the reticles in the 
binoculars. The PSO(s) will be in wireless communication with ship's 
officers on the bridge and scientists in the vessel's operations 
laboratory, so they can advise promptly of the need for avoidance 
maneuvers or a shut-down of the seismic source.
    When marine mammals are detected within or about to enter the 
designated exclusion zone, the airguns will immediately be shut-down if 
necessary. The PSO(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) or 30 minutes 
for species with longer dive durations (mysticetes and large 
odontocetes, including sperm, pygmy sperm, dwarf sperm, killer, and 
beaked whales).

PSO Data and Documentation

    PSOs 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 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 REVELLE is underway without seismic operations (i.e., 
transits, to, from, and through the study area) to collect baseline 
biological data.
    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 seismic source or vessel (e.g., none, 
avoidance, approach, paralleling, etc.), and behavioral pace.
    2. Time, location, heading, speed, activity of the vessel, sea 
state, wind force, 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, as well as information regarding ramp-ups or 
shut-downs will be recorded in a standardized format. Data will be 
entered into an electronic database. The data accuracy will be verified 
by computerized data validity checks as the data are entered and by 
subsequent manual checking of the database by the PSOs at sea. 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.
    Results from the vessel-based observations will provide the 
following information:
    1. The basis for real-time mitigation (airgun 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.
    SIO will submit a comprehensive report to NMFS 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 submitted to NMFS 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, 
and associated seismic survey activities). 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

[[Page 33830]]

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;
     Closest 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 Web site at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm#iha.
    In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by this IHA, 
such as an injury (Level A harassment), serious injury or mortality 
(e.g., ship-strike, gear interaction, and/or entanglement), SIO will 
immediately cease the specified activities and immediately report the 
incident to the Chief of the Permits and Conservation Division, Office 
of Protected Resources, NMFS at 301-427-8401 and/or by email to 
[email protected] and [email protected], and the NMFS 
Pacific Islands Region Marine Mammal Stranding and Entanglement Hotline 
at 1-888-256-9840 ([email protected]). The report must include 
the following information:
     Time, date, and location (latitude/longitude) of the 
incident;
     Name and type of vessel involved;
     Vessel's speed during and leading up to the incident;
     Description of the incident;
     Status of all sound source use in the 24 hours preceding 
the incident;
     Water depth;
     Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, and visibility);
     Description of all marine mammal observations in the 24 
hours preceding the incident;
     Species identification or description of the animal(s) 
involved;
     Fate of the animal(s); and
     Photographs or video footage of the animal(s) (if 
equipment is available).
    Activities shall not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS shall work with SIO to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. SIO may not resume their 
activities until notified by NMFS via letter or email, or telephone.
    In the event that SIO discovers an injured or dead marine mammal, 
and the lead PSO determines that the cause of the injury or death is 
unknown and the death is relatively recent (i.e., in less than a 
moderate state of decomposition as described in the next paragraph), 
SIO will immediately report the incident to the Chief of the Permits 
and Conservation Division, Office of Protected Resources, NMFS, at 301-
427-8401, and/or by email to [email protected] and 
[email protected], and the NMFS Pacific Islands Region Marine 
Mammal Stranding and Entanglement Hotline (1-888-256-9840) and/or by 
email to the Pacific Islands Regional Stranding Coordinator 
([email protected]). The report must include the same 
information identified in the paragraph above. Activities may continue 
while NMFS reviews the circumstances of the incident. NMFS will work 
with SIO to determine whether modifications in the activities are 
appropriate.
    In the event that SIO discovers an injured or dead marine mammal, 
and the lead PSO determines that the injury or death is not associated 
with or related to the activities authorized in the IHA (e.g., 
previously wounded animal, carcass with moderate or advanced 
decomposition, or scavenger damage), SIO will report the incident to 
the Chief of the Permits and Conservation Division, Office of Protected 
Resources, NMFS, at 301-427-8401, and/or by email to 
[email protected] and [email protected], and the NMFS 
Pacific Islands Regional Marine Mammal Stranding and Entanglement 
Hotline (1-888-256-9840), and/or by email to the Pacific Islands 
Regional Stranding Coordinator ([email protected]), within 24 
hours of discovery. SIO will provide photographs or video footage (if 
available) or other documentation of the stranded animal sighting to 
NMFS and the Marine Mammal Stranding Network. Activities may continue 
while NMFS reviews the circumstances of the incident.

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 low-energy marine seismic survey in the 
tropical western Pacific Ocean. 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. There is no evidence that the planned activities could 
result in injury, serious injury, or mortality for which SIO seeks the 
IHA. The required mitigation and monitoring measures will minimize any 
potential risk for injury, serious injury, or mortality.
    The following sections describe SIO'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 in the tropical western Pacific Ocean. The estimates 
are based on a consideration of the number of marine mammals that could 
be harassed by approximately 1,033 km (557.8 nmi) of seismic operations 
with the two GI airgun array to be used as depicted in Figure 1 of the 
IHA application.
    SIO assumes 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-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, SIO provides no 
additional allowance for animals that could be affected by sound 
sources other than airguns.
    The only densities reported for the overall proposed survey area 
are for eight species sighted during vessel-based surveys in coastal 
and oceanic waters of the Sulu Sea, Philippines, covering an area of 
approximately 23,000 km\2\ (6,705.7 nmi\2\), during May

[[Page 33831]]

to June 1994 and 1995 (Dolar et al., 2006). To supplement those density 
data, SIO used densities for seven other species expected to occur in 
the proposed survey area that were sighted during a systematic vessel-
based marine mammal survey in Guam and the southern Commonwealth of the 
Northern Mariana Islands (CNMI) during January to April 2007 (Fulling 
et al., 2011). The cruise area was defined by the boundaries 10 to 
18[deg] North and 142 to 148[deg] East, encompassing an area of 
approximately 585,000 km\2\ (170,558.7 nmi\2\). For five species not 
sighted in either survey, but expected to occur in the proposed survey 
area, SIO also used densities for the ``outer EEZ stratum'' of Hawaiian 
waters, covering approximately 2,240,000 km\2\ (653,079.5 nmi\2\), 
based on a survey conducted in August to November 2002 (Barlow, 2006). 
All three surveys used standard line-transect protocols developed by 
NMFS Southwest Fisheries Science Center. Survey effort was 2,313 km 
(1,248.9 nmi) in the Sulu Sea, 11,033 km (5,957.3 nmi) in the CNMI, and 
13,500 km (7,289.4 nmi) in Hawaii.
    The densities mentioned above have been corrected, by the original 
authors, for trackline detection probability bias, and in one of the 
three areas, for availability bias. Trackline detection probability 
bias is associated with diminishing sightability with increasing 
lateral distance from the trackline f(0). Availability bias refers to 
the fact that there is less than 100% probability of sighting an animal 
that is present along the survey trackline, and it is measured by g(0). 
Dolar et al. (2006) and Fulling et al. (2011) did not correct the CNMI 
densities for g(0), which for all but large (greater than 20) groups of 
dolphins (where g(0) = 1), resulted in underestimates of density. 
Although there is some uncertainty about the representatives of the 
data and the assumptions used in the calculations below, the approach 
used here is believed to be the best available approach.

 Table 4--Estimated Densities and Possible Number Of Marine Mammal Species That Might Be Exposed to Greater Than
 or Equal to 160 dB During SIO's Proposed Seismic Survey (Ensonified Area 1,063.8 km\2\) in the Tropical Western
                                    Pacific Ocean, September to October 2013
----------------------------------------------------------------------------------------------------------------
                                                     Calculated take
                                                    (i.e., estimated
                                                        number of      Approximate  percentage
                                  Density  (/1,000 km\2\)1     exposed to        estimate of  stock       authorization
                                          2         sound levels  >=   (calculated  take) \4\          \5\
                                                      160 dB re  1
                                                     [micro]Pa) \3\
----------------------------------------------------------------------------------------------------------------
Mysticetes:
    Humpback whale..............                NA                 0  0.03....................                 1
    Minke whale.................                NA                 0  0.01....................                 3
    Bryde's whale...............              0.41                 0  0.01....................                 2
    Omura's whale...............                NA                 0  NA......................                 2
    Sei whale...................              0.29                 0  0.03 to 0.02............                 2
    Fin whale...................                NA                 0  0.05 to 0.04............                 7
    Blue whale..................                NA                 0  NA......................                 2
Odontocetes:
    Sperm whale.................              1.23                 1  0.02 (<0.01)............                 5
    Pygmy sperm whale...........              3.19                 3  NA (NA).................                 3
    Dwarf sperm whale...........                 5                 5  0.05 (0.05).............                 5
    Cuvier's beaked whale.......               6.8                 7  0.04 (0.04).............                 7
    Longman's beaked whale......              0.45                 0  NA (NA).................                18
    Ginkgo-toothed beaked whale.                 0                 0  <0.01 (0)...............                 2
    Blainville's beaked whale...              1.28                 1  <0.01 (<0.01)...........                 2
    Killer whale................              0.16                 0  0.08....................                 7
    Short-finned pilot whale....             160.0               170  0.32 (0.32).............               170
    False killer whale..........              1.11                 1  0.06 (<0.01)............                10
    Melon-headed whale..........              20.0                21  0.07 (0.05).............                31
    Pygmy killer whale..........              0.14                 0  0.02 (0)................                 6
    Risso's dolphin.............              15.0                16  0.02 (0.02).............                16
    Bottlenose dolphin..........              55.0                59  0.04 (0.04).............                59
    Rough-toothed dolphin.......              0.29                 0  0.01 (0)................                 9
    Fraser's dolphin............             215.0               229  0.08 (0.08).............               229
    Striped dolphin.............              6.16                 7  <0.01 (<0.01)...........                27
    Pantropical spotted dolphin.             325.0               346  0.08 (0.08).............               346
    Spinner dolphin.............             685.0               729  0.1 (0.1)...............               729
----------------------------------------------------------------------------------------------------------------
NA = Not available or not assessed.
\1\ Densities calculated from Table 4 of Barlow (2006) using the abundance in the outer EEZ stratum and the
  surface area of the stratum give on p. 452 of Barlow (2006).
\2\ A correction factor of 0.5 was applied to the densities of Dolar et al. (2006) because those densities were
  from surveys that included coastal waters, and approximately 50% of the total ensonified area for the proposed
  survey is in deep water, far offshore, where marine mammal densities are expected to be lower; see densities
  in Fulling et al. (2011) and Barlow (2006).
\3\ Calculated take is estimated density (reported density times correction factor) multiplied by the area
  ensonified to 160 dB (rms) around the planned seismic lines, increased by 25% for contingency.
\4\ Requested (and calculated) takes expressed as percentages of the regional populations.
\5\ Requested Take Authorization increased to mean group size for species for which densities were not available
  but that have been sighted in the proposed survey area and for species whose calculated takes were less than
  group size.


[[Page 33832]]

    SIO 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 in the area (in the absence of a seismic 
survey). 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 160 dB radius around the operating 
airguns, excluding areas of overlap. During the proposed survey, the 
transect lines are widely spaced relative to the 160 dB (rms) distance 
(600 m for intermediate water depths and 400 m for deep water depths). 
Thus, the area including overlap is 1.07 times the area excluding 
overlap, so a marine mammal that stayed in the survey areas during the 
entire survey could be exposed slightly more than once, on average. 
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 to be ensonified to that level during 
airgun operations excluding overlap.
    The area expected to be ensonified was determined by entering the 
planned survey lines into a MapInfo GIS, using the GIS to identify the 
relevant areas by ``drawing'' the applicable 160 dB buffer (see Table 1 
of the IHA application) around each seismic line, and then calculating 
the total area within the buffers.
    Applying the approach described above, approximately 851 km\2\ 
(approximately 1,063.8 km\2\ including the 25% contingency) would be 
within the 160 dB isopleth on one or more occasions during the proposed 
survey. The take calculations within the study sites do not explicitly 
add animals to account for the fact that new animals (i.e., turnover) 
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. Because this approach for calculating take 
estimates does not allow for turnover in the marine mammal populations 
in the area during the course of the survey, the actual number of 
individuals exposed may be underestimated, although the conservative 
(i.e., probably overestimated) line-kilometer distances used to 
calculate the area may offset this. Also, the approach assumes that no 
cetaceans will move away or toward the tracklines as the REVELLE 
approaches in response to increasing sound levels before the levels 
reach 160 dB. Another way of interpreting the estimates that follow is 
that they represent the number of individuals that are expected (in 
absence of a seismic program) to occur in the waters that will be 
exposed to greater than or equal to 160 dB (rms).
    SIO's estimates of exposures to various sound levels assume that 
the proposed surveys will be carried out in full; however, the 
ensonified areas calculated using the planned number of line-kilometers 
has been increased by 25% to accommodate lines that may need to be 
repeated, equipment testing, 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. The estimates of the numbers 
of marine mammals potentially exposed to 160 dB (rms) received levels 
are precautionary and probably overestimate the actual numbers of 
marine mammals that could be involved. These estimates assume that 
there will be no weather, equipment, or mitigation delays, which is 
highly unlikely.
    Table 4 (Table 4 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 if no animals moved away from the survey vessel. The requested 
take authorization is given in the far right column of Table 4 (Table 4 
of the IHA application). The requested take authorization has been 
increased to the average mean group sizes from the surveys whose 
densities were used in the calculations, or from Jefferson et al. 
(2008) for species not sighted during the surveys.
    The estimate of the number of individual cetaceans 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 (with 25% 
contingency) in Table 4 of this document (see Table 4 of the IHA 
application). That total (with 25% contingency) includes 0 baleen 
whales, 1 sperm whale, 3 pygmy sperm whales, 5 dwarf sperm whale, 7 
Cuvier's beaked whales, and 1 Blainville's beaked whales could be taken 
by Level B harassment during the proposed seismic survey, which would 
represent 0, <0.01, NA, 0.05, 0.04, 0.01% of the regional populations, 
respectively. Most of the cetaceans potentially taken by Level B 
harassment are delphinids: bottlenose, Fraser's, pantropical spotted, 
and spinner dolphins as well as short-finned pilot whales are estimated 
to be the most common delphinid species in the area, with estimates of 
59, 229, 346, 729, and 170, which would represent 0.04, 0.08, 0.08, 
0.01, and 0.32% of the affected regional populations, respectively.

Encouraging and Coordinating Research

    SIO and NSF will coordinate the planned marine mammal monitoring 
program associated with the proposed seismic survey with other parties 
that express interest in this activity and area. SIO and NSF will 
coordinate with applicable U.S. agencies (e.g., NMFS), and will comply 
with their requirements.

Negligible Impact and Small Numbers Analysis 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

[[Page 33833]]

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 shut-down measures;
    No injuries, serious injuries, or mortalities are anticipated to 
occur as a result of the SIO's planned marine seismic surveys, and none 
are proposed to be authorized by NMFS. Table 3 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 NMFS's and the applicant's proposal to implement mitigation, 
monitoring, and reporting measures to minimize impacts to marine 
mammals. Additionally, the seismic survey will not adversely impact 
marine mammal habitat.
    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. 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). 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 less than a day.
    Of the 26 marine mammal species under NMFS jurisdiction that may or 
are known to likely to occur in the study area, five are listed as 
threatened or endangered under the ESA: humpback, sei, fin, blue, and 
sperm whales. These species are also considered depleted under the 
MMPA. Of these ESA-listed species, incidental take has been requested 
to be authorized for humpback, sei, 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), SIO must cease or reduce 
airgun operations if any marine mammal enters 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, 
and the activity is not expected to impact rates of recruitment or 
survival.
    As mentioned previously, NMFS estimates that 26 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 3 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, the impact of 
conducting a low-energy marine seismic survey in the tropical western 
Pacific Ocean, September to October, 2013, 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 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. NMFS believes that the 
length of the seismic survey, the requirement to implement mitigation 
measures (e.g., shut-down of seismic operations), and the inclusion of 
the monitoring and reporting measures, will reduce the amount and 
severity of the potential impacts from the activity to the degree that 
it will have a negligible impact on the species or stocks in the action 
area.
    NMFS has preliminary determined, provided that the aforementioned 
mitigation and monitoring measures are implemented, that the impact of 
conducting a marine seismic survey in the tropical western Pacific 
Ocean, September to October, 2013, may result, at worst, in a temporary 
modification in behavior and/or low-level physiological effects (Level 
B harassment) of small numbers of certain species of marine mammals. 
See Table 3 for the requested authorized take numbers of marine 
mammals.

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 is subsistence hunting for sperm whales, as well as other 
cetaceans and dugongs in Indonesia (Reeves, 2002; Marsh et al., n.d.). 
The hunting of Bryde's whales in the Philippines appears to be 
prohibited now, but dugongs are still taken there, as well as in Papua 
New Guinea (Marsh et al., n.d.). SIO and NMFS do not expect the 
proposed activities to have any impact on the availability of species 
or stocks of marine mammals in the study area for subsistence users 
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 humpback, sei, fin, blue, and sperm whales. SIO 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, on behalf of SIO, 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

[[Page 33834]]

prior to making a determination on whether or not to issue the IHA. If 
the IHA is issued, NSF and SIO, 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 SIO, 
and NMFS's Office of Protected Resources.

National Environmental Policy Act

    With SIO's complete application, SIO and NSF provided NMFS a 
``Draft Environmental Analysis of a Low-Energy Marine Geophysical 
Survey by the R/V Roger Revelle in the Tropical Western Pacific Ocean, 
September-October 2013,'' prepared by LGL Ltd., Environmental Research 
Associates on behalf of SIO and NSF. 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 and SIO 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 and SIO EA and make a decision 
of whether or not to issue a Finding of No Significant Impact (FONSI).

Proposed Authorization

    As a result of these preliminary determinations, NMFS propose to 
issue an IHA to SIO for conducting the low-energy seismic survey in the 
tropical western Pacific Ocean, provided the previously mentioned 
mitigation, monitoring, and reporting requirements are incorporated. 
The proposed IHA language is provided below:
    Scripps Institution of Oceanography, 8602 La Jolla Shores Drive, La 
Jolla, California 92037, is hereby authorized under section 
101(a)(5)(D) of the Marine Mammal Protection Act (MMPA) (16 U.S.C. 
1371(a)(5)(D)), to harass small numbers of marine mammals incidental to 
a low-energy marine geophysical (seismic) survey conducted by the R/V 
Roger REVELLE (REVELLE) in the tropical western Pacific Ocean, 
September to October 2013:
    1. This Authorization is valid from September 6 through November 
12, 2013.
    2. This Authorization is valid only for the REVELLE's activities 
associated with low-energy seismic and sediment coring survey 
operations that shall occur in the following specified geographic area:
    In the 10 sites in the tropical western Pacific Ocean located 
between approximately 4 to 8[deg] South and approximately 126.5 to 
144.5[deg] East. Water depths in the survey area generally range from 
approximately 450 to 3,000 meters (m) (1,476.4 to 9,842.5 feet [ft]). 
The low-energy seismic survey will be conducted in international waters 
(i.e., high seas) and in the Exclusive Economic Zones (EEZ) of the 
Federated States of Micronesia (Micronesia), the Independent State of 
Papua New Guinea (Papua New Guinea), the Republic of Indonesia 
(Indonesia), and the Republic of the Philippines (Philippines), as 
specified in Scripps Institution of Oceanography's (SIO) Incidental 
Harassment Authorization application and the associated National 
Science Foundation (NSF) and SIO Environmental Analysis.
    3. Species Authorized and Level of Takes.
    (a) The incidental taking of marine mammals, by Level B harassment 
only, is limited to the following species in the waters of the tropical 
western Pacific Ocean:
    (i) Mysticetes--see Table 2 (attached) for authorized species and 
take numbers.
    (ii) Odontocetes--see Table 2 (attached) for authorized species and 
take numbers.
    (iii) If any marine mammal species are encountered during seismic 
activities that are not listed in Table 2 (attached) for authorized 
taking and are likely to be exposed to sound pressure levels (SPLs) 
greater than or equal to 160 dB re 1 [mu]Pa (rms), then the Holder of 
this Authorization must alter speed or course or shut-down the airguns 
to avoid take.
    (b) The taking by injury (Level A harassment), serious injury, or 
death of any of the species listed in Condition 3(a) above or the 
taking of any kind of any other species of marine mammal is prohibited 
and may result in the modification, suspension or revocation of this 
Authorization.
    4. The methods authorized for taking by Level B harassment are 
limited to the following acoustic sources without an amendment to this 
Authorization:
    (a) A two Generator Injector (GI) airgun array (each with a 
discharge volume of 45 cubic inches [in\3\]) with a total volume of 90 
in\3\ (or smaller);
    (b) A multibeam echosounder; and
    (c) A sub-bottom profiler.
    5. The taking of any marine mammal in a manner prohibited under 
this Authorization must be reported immediately to the Office of 
Protected Resources, National Marine Fisheries Service (NMFS), at 301-
427-8401.
    6. Mitigation and Monitoring Requirements.
    The Holder of this Authorization is required to implement the 
following mitigation and monitoring requirements when conducting the 
specified activities to achieve the least practicable adverse impact on 
affected marine mammal species or stocks:
    (a) Utilize one, NMFS-qualified, vessel-based Protected Species 
Observer (PSO) to visually watch for and monitor marine mammals near 
the seismic source vessel during daytime airgun operations (from 
nautical twilight-dawn to nautical twilight-dusk) and before and during 
ramp-ups of airguns day or night. The REVELLE's vessel crew shall also 
assist in detecting marine mammals, when practicable. PSOs shall have 
access to reticle binoculars (7 x 50 Fujinon), big-eye binoculars (25 x 
150), optical range finders, and night vision devices. PSO shifts shall 
last no longer than 4 hours at a time. PSOs shall also make 
observations during daytime periods when the seismic system is not 
operating for comparison of animal abundance and behavior, when 
feasible.
    (b) PSOs shall conduct monitoring while the airgun array and 
streamer(s) are being deployed or recovered from the water.
    (c) Record the following information when a marine mammal is 
sighted:
    (i) 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 including responses to ramp-up), and 
behavioral pace; and
    (ii) Time, location, heading, speed, activity of the vessel 
(including number of airguns operating and whether in state of ramp-up 
or shut-down), Beaufort sea state and wind force, visibility, and sun 
glare; and
    (iii) The data listed under Condition 6(c)(ii) shall 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.
    (d) Visually observe the entire extent of the exclusion zone (180 
dB re 1 [mu]Pa [rms] for cetaceans; see Table 1 [attached] for 
distances) using NMFS-qualified PSOs, for at least 30 minutes prior to 
starting the airgun array (day or night). If the PSO finds a marine 
mammal within the exclusion zone, SIO must delay the seismic survey 
until the

[[Page 33835]]

marine mammal(s) has left the area. If the PSO sees a marine mammal 
that surfaces, then dives below the surface, the PSO shall wait 30 
minutes. If the PSO sees no marine mammals during that time, they 
should assume that the animal has moved beyond the exclusion zone. If 
for any reason the entire radius cannot be seen for the entire 30 
minutes (i.e., rough seas, fog, darkness), or if marine mammals are 
near, approaching, or in the exclusion zone, the airguns may not be 
ramped-up. If one airgun is already running at a source level of at 
least 180 dB re 1 [mu]Pa (rms), SIO may start the second airgun without 
observing the entire exclusion zone for 30 minutes prior, provided no 
marine mammals are known to be near the exclusion zone (in accordance 
with Condition 6[f] below).
    (e) Establish a 180 dB re 1 [mu]Pa (rms) exclusion zone for 
cetaceans before the two GI airgun array (90 in\3\ total) is in 
operation. See Table 1 (attached) for distances and exclusion zones.
    (f) Implement a ``ramp-up'' procedure when starting up at the 
beginning of seismic operations or anytime after the entire array has 
been shut-down for more than 15 minutes, which means starting with a 
single GI airgun and adding a second GI airgun after five minutes. 
During ramp-up, the PSOs shall monitor the exclusion zone, and if 
marine mammals are sighted, a shut-down shall be implemented as though 
the full array (both GI airguns) were operational. Therefore, 
initiation of ramp-up procedures from shut-down requires that the PSOs 
be able to view the full exclusion zone as described in Condition 6(d) 
(above).
    (g) Alter speed or course during seismic operations if a marine 
mammal, based on its position and relative motion, appears likely to 
enter the relevant exclusion zone. If speed or course alteration is not 
safe or practicable, or if after alteration the marine mammal still 
appears likely to enter the exclusion zone, further mitigation 
measures, such as a shut-down, shall be taken.
    (h) Shut-down the airgun(s) if a marine mammal is detected within, 
approaches, or enters the relevant exclusion zone (as defined in Table 
1, attached). A shut-down means all operating airguns are shut-down 
(i.e., turned off).
    (i) Following a shut-down, the airgun activity shall not resume 
until the PSO has visually observed the marine mammal(s) exiting the 
exclusion zone and is not likely to return, or has not been seen within 
the exclusion zone for 15 minutes for species with shorter dive 
durations (small odontocetes) or 30 minutes for species with longer 
dive durations (mysticetes and large odontocetes, including sperm, 
pygmy sperm, dwarf sperm, killer, and beaked whales).
    (j) Following a shut-down and subsequent animal departure, airgun 
operations may resume following ramp-up procedures described in 
Condition 6(f).
    (k) Marine seismic surveys may continue into night and low-light 
hours if such segment(s) of the survey is initiated when the entire 
relevant exclusion zones are visible and can be effectively monitored.
    (l) No initiation of airgun array operations is permitted from a 
shut-down position at night or during low-light hours (such as in dense 
fog or heavy rain) when the entire relevant exclusion zone cannot be 
effectively monitored by the PSO(s) on duty.
    7. Reporting Requirements.
    The Holder of this Authorization is required to:
    (a) Submit a draft report on all activities and monitoring results 
to the Office of Protected Resources, NMFS, within 90 days of the 
completion of the REVELLE's tropical western Pacific Ocean cruise. This 
report must contain and summarize the following information:
    (i) Dates, times, locations, heading, speed, weather, sea 
conditions (including Beaufort sea state and wind force), and 
associated activities during all seismic operations and marine mammal 
sightings;
    (ii) Species, number, location, distance from the vessel, and 
behavior of any marine mammals, as well as associated seismic activity 
(number of shut-downs), observed throughout all monitoring activities.
    (iii) An estimate of the number (by species) of marine mammals 
that: (A) Are known to have been exposed to the seismic activity (based 
on visual observation) at received levels greater than or equal to 160 
dB re 1 [mu]Pa (rms) and/or 180 dB re 1 [mu]Pa (rms) for cetaceans with 
a discussion of any specific behaviors those individuals exhibited; and 
(B) may have been exposed (based on modeled values for the two GI 
airgun array) to the seismic activity at received levels greater than 
or equal to 160 dB re 1 [mu]Pa (rms) and/or 180 dB re 1 [mu]Pa (rms) 
for cetaceans with a discussion of the nature of the probable 
consequences of that exposure on the individuals that have been 
exposed.
    (iv) A description of the implementation and effectiveness of the: 
(A) Terms and Conditions of the Biological Opinion's Incidental Take 
Statement (ITS) (attached); and (B) mitigation measures of the 
Incidental Harassment Authorization. For the Biological Opinion, the 
report shall confirm the implementation of each Term and Condition, as 
well as any conservation recommendations, and describe their 
effectiveness, for minimizing the adverse effects of the action on 
Endangered Species Act-listed marine mammals.
    (b) Submit a final report to the Chief, Permits and Conservation 
Division, Office of Protected Resources, NMFS, within 30 days after 
receiving comments from NMFS on the draft report. If NMFS decides that 
the draft report needs no comments, the draft report shall be 
considered to be the final report.
    8. In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by this 
Authorization, such as an injury (Level A harassment), serious injury 
or mortality (e.g., ship-strike, gear interaction, and/or 
entanglement), SIO shall immediately cease the specified activities and 
immediately report the incident to the Chief of the Permits and 
Conservation Division, Office of Protected Resources, NMFS, at 301-427-
8401 and/or by email to [email protected] and 
[email protected] and the NMFS Pacific Islands Region Marine 
Mammal Stranding and Entanglement Hotline at 1-888-256-9840 
([email protected]). The report must include the following 
information:
    (a) Time, date, and location (latitude/longitude) of the incident; 
the name and type of vessel involved; the vessel's speed during and 
leading up to the incident; description of the incident; status of all 
sound source use in the 24 hours preceding the incident; water depth; 
environmental conditions (e.g., wind speed and direction, Beaufort sea 
state, cloud cover, and visibility); description of marine mammal 
observations in the 24 hours preceding the incident; species 
identification or description of the animal(s) involved; the fate of 
the animal(s); and photographs or video footage of the animal (if 
equipment is available). Activities shall not resume until NMFS is able 
to review the circumstances of the prohibited take. NMFS shall work 
with SIO to determine what is necessary to minimize the likelihood of 
further prohibited take and ensure MMPA compliance. SIO may not resume 
their activities until notified by NMFS via letter, email, or 
telephone.
    In the event that SIO discovers an injured or dead marine mammal, 
and the lead PSO determines that the cause of the injury or death is 
unknown and

[[Page 33836]]

the death is relatively recent (i.e., in less than a moderate state of 
decomposition as described in the next paragraph), SIO will immediately 
report the incident to the Chief of the Permits and Conservation 
Division, Office of Protected Resources, NMFS, at 301-427-8401, and/or 
by email to [email protected] and [email protected], and 
the NMFS Pacific Islands Marine Mammal Stranding and Entanglement 
Hotline (1-888-256-9840) and/or by email to the NMFS Pacific Islands 
Regional Stranding Coordinator ([email protected]). The report 
must include the same information identified in Condition 8(a) above. 
Activities may continue while NMFS reviews the circumstances of the 
incident. NMFS will work with SIO to determine whether modifications in 
the activities are appropriate.
    In the event that SIO discovers an injured or dead marine mammal, 
and the lead PSO determines that the injury or death is not associated 
with or related to the activities authorized in Condition 2 of this 
Authorization (e.g., previously wounded animal, carcass with moderate 
to advanced decomposition, or scavenger damage), SIO shall report the 
incident to the Chief of the Permits and Conservation Division, Office 
of Protected Resources, NMFS, at 301-427-8401, and/or by email to 
[email protected] and [email protected], and the NMFS 
Pacific Islands Marine Mammal Stranding and Entanglement Hotline (1-
888-256-9840) and/or by email to the Pacific Islands Regional Stranding 
Coordinator ([email protected]), within 24 hours of the 
discovery. SIO shall provide photographs or video footage (if 
available) or other documentation of the stranded animal sighting to 
NMFS and the Marine Mammal Stranding Network. Activities may continue 
while NMFS reviews the circumstances of the incident.
    9. SIO is required to comply with the Terms and Conditions of the 
ITS corresponding to NMFS's Biological Opinion issued to both SIO, NSF, 
and NMFS's Office of Protected Resources (attached).
    10. A copy of this Authorization and the ITS must be in the 
possession of all contractors and PSOs operating under the authority of 
this Incidental Harassment Authorization.

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: May 31, 2013.
Helen M. Golde,
Deputy Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2013-13280 Filed 6-4-13; 8:45 am]
BILLING CODE 3510-22-P