Takes of Marine Mammals Incidental to Specified Activities; Three Marine Geophysical Surveys in the Northeast Pacific Ocean, June Through July 2012, 25966-25991 [2012-10627]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 77, Number 85 (Wednesday, May 2, 2012)]
[Notices]
[Pages 25966-25991]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-10627]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XB105


Takes of Marine Mammals Incidental to Specified Activities; Three 
Marine Geophysical Surveys in the Northeast Pacific Ocean, June Through 
July 2012

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

ACTION: Notice; proposed incidental harassment authorization; request 
for comments.

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SUMMARY: We have received an application from the Lamont-Doherty Earth 
Observatory, a part of Columbia University, for an Incidental 
Harassment Authorization to take marine mammals, by harassment, 
incidental to conducting three consecutive marine geophysical surveys 
in the northeast Pacific Ocean, June through July 2012.

DATES: Comments and information must be received no later than May 31, 
2012.

ADDRESSES: Comments on the application should be addressed to Tammy C. 
Adams, Acting Chief, Permits and Conservation Division, Office of 
Protected Resources, National Marine Fisheries Service, 1315 East-West 
Highway, Silver Spring, MD 20910-3225. The mailbox address for 
providing email comments is ITP.Cody@noaa.gov. We are 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 submitted comments are a part of the public record and we will 
post to https://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications 
without change. All Personal Identifying Information (for example, 
name, address, etc.) voluntarily submitted by the commenter may be 
publicly accessible. Do not submit confidential business information or 
otherwise sensitive or protected information.
    To obtain an electronic copy of the application containing a list 
of the references used in this document, write to the previously 
mentioned address, telephone the contact listed here (see FOR FURTHER 
INFORMATION CONTACT), or visit the Internet at: https://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications.
    The National Science Foundation's (Foundation) draft Environmental 
Assessment (Assessment) pursuant to the National Environmental Policy 
Act of 1969 and Executive Order 12114 is also available at the same 
Internet address. The Assessment incorporates an ``Environmental 
Assessment of a marine geophysical survey by the R/V Marcus G. Langseth 
in the northeastern Pacific Ocean, June-July 2012,'' prepared by LGL 
Limited environmental research associates, on behalf of the Foundation. 
The public can view documents cited in this notice by appointment, 
during regular business hours, at the aforementioned address.

FOR FURTHER INFORMATION CONTACT: Jeannine Cody or Howard Goldstein, 
National Marine Fisheries Service, Office of Protected Resources, (301) 
427-8401.

SUPPLEMENTARY INFORMATION: 

Background

    Section 101(a)(5)(D) of the Marine Mammal Protection Act of 1972, 
as amended (MMPA; 16 U.S.C. 1361 et seq.) directs the Secretary of 
Commerce 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: (1) We make certain findings; (2) the taking is 
limited to harassment; and (3) we provide a notice of a proposed 
authorization to the public for review.
    We shall grant authorization for the incidental taking of small 
numbers of marine mammals if we find that the taking will have a 
negligible impact on the species or stock(s), and will not have an 
unmitigable adverse impact on the availability of the species or 
stock(s) for subsistence uses (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. We have 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 Marine Mammal Protection Act 
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 Act 
establishes a 45-day time limit for our 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, we 
must either issue or deny the authorization and must publish a notice 
in the Federal Register within 30 days of our determination to issue or 
deny the authorization.
    Except with respect to certain activities not pertinent here, the 
Marine Mammal Protection Act 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

    We received an application on January 27, 2012, from the Lamont-
Doherty Earth Observatory (Observatory) for the taking by harassment, 
of small numbers of marine mammals, incidental to conducting three 
separate marine geophysical surveys in the northeast Pacific Ocean. We 
determined the application complete and adequate on March 27, 2012.
    The Observatory, with research funding from the U.S. National 
Science Foundation (Foundation), plans to conduct three research 
studies on the Juan de Fuca Plate, the Cascadia thrust zone, and the 
Cascadia subduction margin in waters off the Oregon and Washington 
coasts. The Observatory has proposed to conduct the first survey from 
June 11 through July 5, 2012, the second survey from July 5 through 
July 8, 2012, and the third survey from July 12 through July 23, 2012.
    The Observatory plans to use one source vessel, the R/V Marcus G. 
Langseth (Langseth), a seismic airgun array, a single hydrophone 
streamer, and ocean bottom seismometers to conduct the geophysical 
surveys.

[[Page 25967]]

    The proposed surveys will provide data necessary to:
     Characterize the evolution and state of hydration of the 
Juan de Fuca plate at the Cascadia subduction zone;
     Provide information on the buried structures in the 
region; and
     Assess the location, physical state, fluid budget, and 
methane systems of the Juan de Fuca plate boundary and overlying crust.
    The results of the three studies would provide background 
information for generating improved earthquake hazards analyses and a 
better understanding of the processes that control megathrust 
earthquakes which are produced by a sudden slip along the boundary 
between a subducting and an overriding plate.
    In addition to the operations of the seismic airgun array and 
hydrophone streamer, and the ocean bottom seismometers (seismometers), 
the Observatory intends to operate a multibeam echosounder and a sub-
bottom profiler continuously throughout the surveys.
    Acoustic stimuli (i.e., increased underwater sound) generated 
during the operation of the seismic airgun arrays, may have the 
potential to cause a short-term behavioral disturbance for marine 
mammals in the survey area. This is the principal means of marine 
mammal taking associated with these activities and the Observatory has 
requested an authorization to take 26 species of marine mammals by 
Level B harassment. We do not expect that the use of the multibeam 
echosounder, the sub-bottom profiler, or the ocean bottom seismometer 
will result in the take of marine mammals and will discuss our 
reasoning later in this notice. Also, we do not expect take to result 
from a collision with the Langseth because it is a single vessel moving 
at relatively slow speeds (4.6 knots (kts); 8.5 kilometers per hour 
(km/h); 5.3 miles per hour (mph)) during seismic acquisition within the 
survey, for a relatively short period of time. It is likely that any 
marine mammal would be able to avoid the vessel.

Description of the Specified Activities

Juan de Fuca Plate Survey

    The first proposed seismic survey would begin on June 11, 2012, and 
end on July 5, 2012. The Langseth would depart from Astoria, Oregon on 
June 11, 2012, and transit to the survey area in the northeast Pacific 
Ocean in international waters and the Exclusive Economic Zones of the 
United States and Canada. The study area will encompass an area bounded 
by approximately 43-48 degrees ([deg]) North by approximately 124-
130[deg] East (see Figure 1 in the Observatory's Application 
1). Water depths in the survey area range from approximately 
50 to 3,000 meters (m) (164 feet (ft) to 1.9 miles (mi)). At the 
conclusion of the first survey, the Langseth would begin a second 
three-day seismic survey on July 5, 2012, in the same area.
    Typically, two-dimensional surveys such as this one, acquire data 
along single track lines with wide intervals; cover large areas; 
provide a coarse sampled subsurface image; and project less acoustic 
energy into the environment than other types of seismic surveys. During 
this survey, the Langseth would deploy a 36-airgun array as an energy 
source, an 8-kilometer (km)-long (4.9 mi-long) hydrophone streamer, and 
46 seismometers. The seismometers are portable, self-contained passive 
receiver systems designed to sit on the seafloor and record seismic 
signals generated primarily by airguns and earthquakes. As the Langseth 
tows the airgun array along the survey lines, the hydrophone streamer 
receives the returning acoustic signals and transfers the data to the 
vessel's on-board processing system. The seismometers also record and 
store the returning signals for later analysis.
    The Observatory plans to discharge the airgun array along three 
long transect lines and three semi-circular arcs using the seismometers 
as the receivers and then repeat along the long transect lines in 
multichannel seismic mode using the 8-km streamer as the receiver (see 
Figure 1 in the Observatory's Application 1). Also, the 
Observatory will use one support vessel, the R/V Oceanus (Oceanus) to 
deploy 46 seismometers on the northern onshore-offshore line, retrieve 
the 46 seismometers from the northern line, and then deploy 39 
seismometers on the southern onshore-offshore lines and retrieve them 
at the conclusion of the survey.
    The first study (e.g., equipment testing, startup, line changes, 
repeat coverage of any areas, and equipment recovery) will require 
approximately 17 days to complete approximately 3,051 km (1,895.8 mi) 
of transect lines. The total survey effort including contingency will 
consist of approximately 2,878 km (1,788.3) of transect lines in depths 
greater than 1,000 m (621.3 mi), 102 km (63.4 mi) in depths 100 to 
1,000 m (328 to 3,280 ft), and 71 km (44.1 mi) in water depths less 
than 100 m (328 ft). The northern and southern onshore-offshore lines 
are 70 to 310 km (43.4 to 192.6 mi) and 15 to 450 km (9.3 to 279.6 mi) 
from shore, respectively.
    Data acquisition will include approximately 408 hours of airgun 
operations (i.e., 17 days over 24 hours). The Observatory, the 
Langseth's operator, will conduct all planned seismic activities, with 
on-board assistance by the scientists who have proposed the study. The 
Principal Investigators for the survey are Drs. S. Carbotte and H. 
Carton (Lamont Doherty Earth Observatory, New York) and P. Canales 
(Woods Hole Oceanographic Institution, Massachusetts). The vessel is 
self-contained and the crew will live aboard the vessel for the entire 
cruise.

Cascadia Thrust Zone Survey

    The second proposed survey would begin on July 5, 2012, and end on 
July 8, 2012. The survey would take place in the U.S. Exclusive 
Economic Zone in waters off of the Oregon and Washington coasts. The 
study area will encompass an area bounded by approximately 43.5-47[deg] 
North by approximately 124-125[deg] East (see Figure 1 in the 
Observatory's Application 2). Water depths in the survey area 
range from approximately 50 to 1,000 m (164 ft to 0.62 mi). At the 
conclusion of this survey, the Langseth would return to Astoria, Oregon 
on July 8, 2012.
    The Langseth would deploy a 36-airgun array as an energy source, 12 
seismometers, and 48 seismometers (33 in Oregon and 15 in Washington) 
onshore (on land). As stated previously, as the Langseth tows the 
airgun array along the survey lines, the seismometers record the 
returning acoustic signals for later analysis. The Observatory proposes 
to use the Oceanus to deploy and retrieve the seismometers.
    The Observatory plans to discharge the airgun array along a grid of 
lines off Oregon and along an onshore-offshore line off Washington (see 
Figure 1 in the Observatory's Application 2).
    The proposed study (e.g., equipment testing, startup, line changes, 
repeat coverage of any areas, and equipment recovery) will require 
approximately 3 days to complete approximately 793 km (492.7 mi) of 
transect lines. The total survey effort including contingency will 
consist of approximately 5 km (3.1 mi) of transect lines in depths 
greater than 1,000 m (621.3 mi), 501 km (311.3 mi) in depths 100 to 
1,000 m (328 to 3,280 ft), and 287 km (178.3 mi) in water depths less 
than 100 m (328 ft). The northern and southern legs of the onshore-
offshore lines are 15 to 70 km (9.3 to 43.5 mi) and 15 to 50 km (9.3 to 
31.1 mi) from shore, respectively.
    Data acquisition will include approximately 72 hours of airgun 
operations (i.e., 3 days over 24 hours). The Principal Investigators 
for the

[[Page 25968]]

second survey are Drs. A.M Trehu (Oregon State University) and G. Abers 
and H. Carton (Lamont Doherty Earth Observatory, New York). The vessel 
is self-contained and the crew will live aboard the vessel for the 
entire cruise.

Cascadia Subduction Margin Survey

    The last seismic survey would begin on July 12, 2012, and end on 
July 23, 2012. The Langseth would depart from Astoria, Oregon on July 
12, 2012, and transit to waters off of the Washington coast. The study 
area encompasses an area bounded by approximately 46.5-47.5[deg] North 
by approximately 124.5-126[deg] East (see Figure 1 in the Observatory's 
Application 3). Water depths in the survey area range from 
approximately 95 to 2,650 m (311.7 ft to 1.6 mi). At the conclusion of 
this survey, the Langseth would return to Astoria, Oregon on July 23, 
2012.
    The Langseth would deploy a 36-airgun array as an energy source and 
an 8-km-long (4.9 mi-long) hydrophone streamer. The Observatory plans 
to discharge the airgun array along nine parallel lines that are spaced 
eight km apart. If time permits, the Langseth would survey an 
additional two lines perpendicular to the parallel lines (see Figure 1 
in the Observatory's Application 3).
    The proposed study (e.g., equipment testing, startup, line changes, 
repeat coverage of any areas, and equipment recovery) will require 
approximately 10 days to complete approximately 1,147 km (712.7 mi) of 
transect lines. The total survey effort including contingency will 
consist of approximately 785 km (487.8 mi) of transect lines in depths 
greater than1,000 m (621.3 mi), 350 km (217.5 mi) of transect lines in 
depths 100 to 1,000 m (328 to 3,280 ft), and 12 km (7.5 mi) of transect 
lines in water depths less than 100 m (328 ft). The survey area is 32 
to 150 km (19.9 to 93.2 mi) from shore.
    Data acquisition will include approximately 240 hours of airgun 
operations (i.e., 10 days over 24 hours). The Principal Investigators 
for the third survey are Drs. W.S. Holbrook (University of Wyoming), 
A.M. Trehu (Oregon State University), H.P. Johnson (University of 
Washington), G.M. Kent (University of Nevada), and K. Keranen 
(University of Oklahoma). The vessel is self-contained and the crew 
will live aboard the vessel for the entire cruise.

Vessel Specifications

    The Langseth, owned by the Foundation, is a seismic research vessel 
with a quiet propulsion system that avoids interference with the 
seismic signals emanating from the airgun array. The vessel is 71.5 m 
(235 ft) long; has a beam of 17.0 m (56 ft); a maximum draft of 5.9 m 
(19 ft); and a gross tonnage of 3,834 pounds. It's two 3,550 horsepower 
(hp) Bergen BRG-6 diesel engines drive two propellers. Each propeller 
has four blades and the shaft typically rotates at 750 revolutions per 
minute. The vessel also has an 800-hp bowthruster, which is not used 
during seismic acquisition. The Langseth's operational speed during 
seismic acquisition will be approximately 4.6 kts (8.5 km/h; 5.3 mph) 
and the cruising speed of the vessel outside of seismic operations is 
18.5 km/h (11.5 mph or 10 kts).
    The Langseth will tow the 36-airgun array, as well as the 
hydrophone streamer during the first and last surveys, along 
predetermined lines. When the Langseth is towing the airgun array and 
the hydrophone streamer, the turning rate of the vessel is limited to 
five degrees per minute. Thus, the maneuverability of the vessel is 
limited during operations with the streamer.
    The vessel also has an observation tower from which protected 
species visual observers (observer) will watch for marine mammals 
before and during the proposed airgun operations. When stationed on the 
observation platform, the observer's eye level will be approximately 
21.5 m (71 ft) above sea level providing the observer an unobstructed 
view around the entire vessel.
    Some minor deviation from these dates is possible, depending on 
logistics, weather conditions, and the need to repeat some lines if 
data quality is substandard. Therefore, we propose to issue an 
authorization to the Observatory that would be effective from June 9, 
2012, to August 27, 2012.

Acoustic Source Specifications

Seismic Airguns

    The Langseth will deploy a 36-airgun array, with a total volume of 
approximately 6,600 cubic inches (in\3\) at a tow depth of 9, 12, or 15 
m (29.5, 39.4, or 49.2 ft). The airguns are a mixture of Bolt 1500LL 
and Bolt 1900LLX airguns ranging in size from 40 to 360 in\3\, with a 
firing pressure of 1,900 pounds per square inch. The dominant frequency 
components range from zero to 188 Hertz (Hz). The array configuration 
consists of four identical linear strings, with 10 airguns on each 
string. The Langseth's crew will space the first and last airguns 16 m 
(52 ft) apart from one another. Of the 10 airguns, nine will fire 
simultaneously while the tenth airgun will serve as a spare. The crew 
will turn on the spare airgun in case one of the other airguns fail. 
The Langseth will distribute the array across an area of approximately 
24 by 16 m (78.7 by 52.5 ft) and will tow the array approximately 100 m 
(328 ft) behind the vessel.
    Juan de Fuca Plate Survey: This survey's array tow depth will be 9 
m (29.5 ft) for the multichannel seismic survey using the hydrophone 
streamer and 12 m (39.4 ft) during the survey using the seismometers. 
During the multichannel seismic survey, each airgun array will emit a 
pulse at approximately 16-second (s) intervals which corresponds to a 
shot interval of approximately 37.5 m (123 ft). During the survey using 
the seismometers, each airgun array will emit a pulse at approximately 
200-s intervals which corresponds to a shot interval of approximately 
500 m (1,640.4 ft). During firing, the airguns will emit a brief 
(approximately 0.1 s) pulse of sound; during the intervening periods of 
operations, the airguns are silent.
    Cascadia Thrust Zone Survey: The survey's array tow depth will be 
12 m (39.4 ft). During this survey, each airgun array will emit a pulse 
at approximately 40-s intervals which corresponds to a shot interval of 
approximately 100 m (328 ft). During firing, the airguns will emit a 
brief (approximately 0.1 s) pulse of sound; during the intervening 
periods of operations, the airguns are silent.
    Cascadia Subduction Margin Survey: The survey's array tow depth 
will be 15 m (49.2 ft). During this survey, each airgun array will emit 
a pulse at approximately 20-s intervals which corresponds to a shot 
interval of approximately 50 m (164 ft). During firing, the airguns 
will emit a brief (approximately 0.1 s) pulse of sound; during the 
intervening periods of operations, the airguns are silent.

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 ([micro]Pa), where 1 pascal (Pa) is 
the pressure resulting from a force of one newton exerted over an area 
of one square meter. In this document, we express sound pressure level 
as the ratio of a measured sound pressure and a reference level. The 
commonly used reference pressure level in underwater acoustics is 1 
FPa, and the units for sound pressure levels are dB re: 1 [mu]Pa.

Sound pressure level (in decibels (dB)) = 20 log (pressure/reference 
pressure)


[[Page 25969]]


    Sound pressure level is an instantaneous measurement and can be 
expressed as the peak, the peak-peak (p-p), or the root mean square. 
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 sound pressure level in this document refer to the root mean square 
unless otherwise noted. Sound pressure level does not take the duration 
of a sound into account.

Characteristics of the Airgun Pulses

    Airguns function by venting high-pressure air into the water which 
creates an air bubble. The pressure signature of an individual airgun 
consists of a sharp rise and then fall in pressure, followed by several 
positive and negative pressure excursions caused by the oscillation of 
the resulting air bubble. The oscillation of the air bubble transmits 
sounds downward through the seafloor and the amount of sound 
transmitted in the near horizontal directions is reduced. However, the 
airgun array also emits sounds that travel horizontally toward non-
target areas.
    The nominal source levels of the airgun array used by the 
Observatory on the Langseth is 236 to 265 dB re: 1 
[mu]Pa(p-p) and the root mean square value for a given 
airgun pulse is typically 16 dB re: 1 [mu]Pa lower than the peak-to-
peak value (Greene, 1997; McCauley et al., 1998, 2000a). However, the 
difference between root mean square and peak or peak-to-peak values for 
a given pulse depends on the frequency content and duration of the 
pulse, among other factors.
    Accordingly, the Observatory has predicted the received sound 
levels in relation to distance and direction from the 36-airgun array 
and the single Bolt 1900LL 40-in\3\ airgun, which will be used during 
power downs. Appendix A of the Foundation's Environmental Assessment 
provides a detailed description of the modeling for marine seismic 
source arrays for species mitigation and Appendix B(3) of the 
Assessment discusses the characteristics of the airgun pulses. These 
are the source levels applicable to downward propagation. The effective 
source levels for horizontal propagation are lower than those for 
downward propagation because of the directional nature of the sound 
from the airgun array. Refer to the authorization application and 
Assessment for additional information.

Predicted Sound Levels for the Airguns

    Tolstoy et al., (2009) reported results for propagation 
measurements of pulses from the Langseth's 36-airgun, 6,600 in\3\ array 
in shallow-water (approximately 50 m (164 ft)) and deep-water depths 
(approximately 1,600 m (5,249 ft)) in the Gulf of Mexico in 2007 and 
2008. Results of the Gulf of Mexico calibration study (Tolstoy et al., 
2009) showed that radii around the airguns for various received levels 
varied with water depth and that sound propagation varied with array 
tow depth.
    The Observatory used the results from the Gulf of Mexico study to 
determine the algorithm for its model that calculates the exclusion 
zones for the 36-airgun array and the single airgun. These values 
designate mitigation zones and the Observatory uses them to estimate 
take (described in greater detail in Section VII of the application and 
Section IV of the Foundation's Environmental Assessment) for marine 
mammals.
    Comparison of the Tolstoy et al. (2009) calibration study with the 
Observatory's model for the Langseth's 36-airgun array indicated that 
the model represents the actual received levels, within the first few 
kilometers and the locations of the predicted exclusions zones. 
However, the model for deep water (greater than 1,000 m; 3,280 ft) 
overestimated the received sound levels at a given distance but is 
still valid for defining exclusion zones at various tow depths. Because 
the tow depth of the array in the calibration study is less shallow (6 
m; 19.7 ft) than the tow depths in the proposed surveys (9, 12, or 15 
m; 29.5, 39.4, or 49.2 ft), the Observatory used the following 
correction factors for estimating the received levels during the 
proposed surveys (see Table 1). The correction factors are the ratios 
of the 160-,180-, and 190-dB distances from the modeled results for the 
6,600 in\3\ airgun array towed at 6 m (19.7 ft) versus 9, 12, or 15 m 
(29.5, 39.4, or 49.2 ft) (LGL, 2008).

Table 1--Correction Factors for Estimating the Received Levels for Three
 Proposed Surveys in the Northeast Pacific Ocean, during June-July 2012
------------------------------------------------------------------------
               Array tow depth                  160-dB   180-dB   190-dB
------------------------------------------------------------------------
9............................................    1.285    1.338    1.364
12...........................................    1.467    1.577    1.545
15...........................................    1.647    1.718    1.727
------------------------------------------------------------------------

    For a single airgun, the tow depth has minimal effect on the 
maximum near-field output and the shape of the frequency spectrum for 
the single airgun; thus, the predicted exclusion zones are essentially 
the same at different tow depths. The Observatory's model does not 
allow for bottom interactions, and thus is most directly applicable to 
deep water.
    Table 2 summarizes the predicted distances at which one would 
expect to receive three sound levels (160-, 180-, and 190-dB) from the 
36-airgun array and a single airgun. To avoid the potential for injury 
or permanent physiological damage (Level A harassment), we (NMFS, 1995, 
2000), we have concluded that cetaceans and pinnipeds should not be 
exposed to pulsed underwater noise at received levels exceeding 180 dB 
re: 1 [mu]Pa and 190 dB re: 1 [mu]Pa, respectively. The 180-dB and 190-
dB level shutdown criteria are applicable to cetaceans and pinnipeds, 
respectively, specified by us (NMFS, 1995, 2000). The Observatory used 
these levels to establish the exclusion zones. We also assume that 
marine mammals exposed to levels exceeding 160 dB re: 1 [micro]Pa may 
experience Level B harassment.

 Table 2--Measured (Array) or Predicted (Single Airgun) Distances to Which Sound Levels Greater Than or Equal to
   160, 180, and 190 dB re: 1 [mu]Pa That Could Be Received During the Three Proposed Surveys in the Northeast
                                      Pacific Ocean, During June-July 2012
----------------------------------------------------------------------------------------------------------------
                                                                                 Predicted RMS distances \2\ (m)
       Source and volume (in\3\)         Tow depth         Water depth (m)      --------------------------------
                                            (m)                                    160 dB     180 dB     190 dB
----------------------------------------------------------------------------------------------------------------
Single Bolt airgun (40 in\3\).........     \1\ 6-15  >1,000....................        385         40         12
                                                     100 to 1,000..............        578         60         18
                                                     <100......................      1,050        296        150
36-Airgun Array (6,600 in\3\).........            9  >1,000....................      3,850        940        400
                                                     100 to 1,000..............     12,200      1,540        550
                                                     <100......................     20,550      2,140        680

[[Page 25970]]

 
36-Airgun Array (6,600 in\3\).........           12  >1,000....................      4,400      1,100        460
                                                     100 to 1,000..............     13,935      1,810        615
                                                     <100......................     23,470      2,250        770
36-Airgun Array (6,600 in\3\).........           15  >1,000....................      4,490      1,200        520
                                                     100 to 1,000..............     15,650      1,975        690
                                                     <100......................     26,350      2,750        865
----------------------------------------------------------------------------------------------------------------
\1\ For a single airgun, the tow depth has minimal effect on the maximum near-field output and the shape of the
  frequency spectrum for the single airgun; thus, the predicted exclusion zones are essentially the same at
  different tow depths.
\2\ The Observatory has based the radii for the array on data in Tolstoy et al. (2009) and has corrected for tow
  depth using modeled results. They have based the predicted radii for a single airgun upon their model (see
  Figure 3 in application 1).

Ocean Bottom Seismometers

    The Observatory proposes to use the Woods Hole Oceanographic 
Institution ``D2'' seismometer during the cruise. The seismometer is 
approximately one meter in height and has a maximum diameter of 50 
centimeters (cm). The anchor (2.5 x 30.5 x 38.1 cm) is hot-rolled steel 
and weighs 23 kilograms. The acoustic release transponder, located on 
the vessel, communicates with the seismometer at a frequency of 9 to 11 
kilohertz (kHz). The source level of the release signal is 190 dB re: 1 
[mu]Pa. The received signal activates the seismometer's burn-wire 
release assembly which then releases the seismometer from the anchor. 
The seismometer then floats to the ocean surface for retrieval by the 
Oceanus.

Multibeam Echosounder

    The Langseth will operate a Kongsberg EM 122 multibeam echosounder 
concurrently during airgun operations to map characteristics of the 
ocean floor. The hull-mounted echosounder emits brief pulses of sound 
(also called a ping) (10.5 to 13 kHz) in a fan-shaped beam that extends 
downward and to the sides of the ship. The transmitting beamwidth is 1 
or 2[deg] fore-aft and 150[deg] athwartship and the maximum source 
level is 242 dB re: 1 [mu]Pa.
    For deep-water operations, each ping consists of eight (in water 
greater than 1,000 m; 3,280 ft) or four (less than 1,000 m; 3,280 ft) 
successive, fan-shaped transmissions, from two to 15 milliseconds (ms) 
in duration and each ensonifying a sector that extends 1[deg] fore-aft. 
Continuous wave pulses increase from 2 to 15 ms long in water depths up 
to 2,600 m (8,530 ft). The echosounder uses frequency-modulated chirp 
pulses up to 100-ms long in water greater than 2,600 m (8,530 ft). The 
successive transmissions span an overall cross-track angular extent of 
about 150[deg], with 2-ms gaps between the pulses for successive 
sectors.

Sub-Bottom Profiler

    The Langseth will also operate a Knudsen Chirp 3260 sub-bottom 
profiler concurrently during airgun and echosounder operations to 
provide information about the sedimentary features and bottom 
topography. The profiler is capable of reaching depths of 10,000 m (6.2 
mi). The dominant frequency component is 3.5 kHz and a hull-mounted 
transducer on the vessel directs the beam downward in a 27[deg] cone. 
The power output is 10 kilowatts (kW), but the actual maximum radiated 
power is three kilowatts or 222 dB re: 1 [mu]Pa. The ping duration is 
up to 64 ms with a pulse interval of one second, but a common mode of 
operation is to broadcast five pulses at 1-s intervals followed by a 5-
s pause.
    We expect that acoustic stimuli resulting from the proposed 
operation of the single airgun or the 36-airgun array has the potential 
to harass marine mammals, incidental to the conduct of the proposed 
seismic survey. We also expect these disturbances to be temporary and 
result in a temporary modification in behavior and/or low-level 
physiological effects (Level B harassment only) of small numbers of 
certain species of marine mammals.
    We do not expect that the movement of the Langseth, during the 
conduct of the seismic survey, has the potential to harass marine 
mammals because of the relatively slow operation speed of the vessel 
(4.6 kts; 8.5 km/hr; 5.3 mph) during seismic acquisition.

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

    Thirty-one marine mammal species under our jurisdiction may occur 
in the proposed survey areas, including 19 odontocetes (toothed 
cetaceans), seven mysticetes (baleen whales), and five species of 
pinniped during June through July, 2012. Six of these species and two 
stocks are listed as endangered under the Endangered Species Act of 
1973 (ESA; 16 U.S.C. 1531 et seq.), including the blue (Balaenoptera 
musculus), fin (Balaenoptera physalus), humpback (Megaptera 
novaeangliae), north Pacific right (Eubalaena japonica), sei 
(Balaenoptera borealis), and sperm (Physeter macrocephalus) whales; the 
southern resident stock of killer (Orcinus orca) whales; and the 
eastern U.S. stock of the Steller sea lion (Eumetopias jubatus).
    The U.S. Fish and Wildlife Service manages the northern sea otter 
(Enhydra lutis) (listed under the Endangered Species Act). Because this 
species is not under our jurisdiction, we do not consider this species 
further in this notice.
    Based on available data, the Observatory does not expect to 
encounter five of the 31 species in the proposed survey areas. They 
include the: the north Pacific right, false killer (Pseudorca 
crassidens), and short-finned pilot (Globicephala macrorhynchus) 
whales; the California sea lion (Zalophus californianus); and the 
bottlenose dolphin (Tursiops truncatus) because of these species' rare 
and/or extralimital occurrence in the survey areas. Accordingly, we did 
not consider these species in greater detail and the proposed 
authorization will only address requested take authorizations for 26 
species: Six mysticetes, 16 odontocetes, and four species of pinniped.
    Of these 26 species, the most common marine mammals in the survey 
area would be the: harbor porpoise (Phocoena phocoena), Dall's porpoise 
(Phocoenoides dalli), northern fur seal (Callorhinus ursinus), and 
northern elephant seal (Mirounga angustirostris).

[[Page 25971]]

    Table 3 presents information on the abundance, distribution, and 
conservation status of the marine mammals that may occur in the 
proposed survey area June through July 2012.

  Table 3--Habitat, Abundance, Density, and ESA Status of Marine Mammals That May Occur in or Near the Proposed
                               Seismic Survey Areas in the Northeast Pacific Ocean
[See text and Tables 2 and 3 in the Observatory's applications and the Foundation's Environmental Assessment for
                                                further details.]
----------------------------------------------------------------------------------------------------------------
                                                                                                    Density \3\
           Species               Occurrence in        Habitat      Abundance in the    ESA \2\      /
                                     area                           NW Pacific \1\                 1,000 km \2\
----------------------------------------------------------------------------------------------------------------
          Mysticetes
 
North Pacific right whale....  Rare............   Coastal, shelf,            \4\ 31  EN                        0
                                                  offshore.
Gray whale...................  Common *........  Coastal, shallow        \5\ 19,126  DL                     3.21
                                                  shelf.
Humpback whale...............  Common *........  Mainly nearshore        \6\ 20,800  EN                     0.81
                                                  and banks.
Minke whale..................  Rare............  Nearshore,               \7\ 9,000  NL                     0.46
                                                  offshore.
Sei whale....................  Rare............  Mostly pelagic..        \8\ 12,620  EN                     0.16
Fin whale....................  Common..........  Slope, pelagic..       \9\ 13,620-  EN                     1.29
                                                                             18,680
Blue whale...................  Rare............  Pelagic and                  2,497  EN                     0.18
                                                  coastal.
 
         Odontocetes
 
Sperm whale..................  Common..........  Pelagic, steep         \10\ 24,000  EN                     1.02
                                                  topography.
Pygmy sperm whale............  Rare............  Deep, off shelf.              N.A.  NL                     0.71
Dwarf sperm whale............  Rare............  Deep, shelf,                  N.A.  NL                     0.71
                                                  slope.
Cuvier's beaked whale........  Common..........  Pelagic.........             2,143  NL                     0.43
Baird's beaked whale.........  Common..........  Pelagic.........               907  NL                     1.18
Blainville's beaked whale....  Rare............  Pelagic.........        \11\ 1,024  NL                     1.75
Hubb's beaked whale..........  Rare............  Slope, offshore.        \11\ 1,024  NL                     1.75
Stejneger's beaked whale.....  Common..........  Slope, offshore.        \11\ 1,024  NL                     1.75
Common bottlenose dolphin....  Rare............  Coastal, shelf,         \12\ 1,006  NL                        0
                                                  deep.
Striped dolphin..............  Rare............  Off continental             10,908  NL                     0.04
                                                  shelf.
Short-beaked common dolphin..  Common..........  Shelf, pelagic,            411,211  NL                    10.28
                                                  mounts.
Pacific white-sided dolphin..  Abundant........  Offshore, slope.            26,930  NL                    34.91
Northern right whale dolphin.  Common..........  Slope, offshore              8,334  NL                    12.88
                                                  waters.
Risso's dolphin..............  Common..........  Shelf, slope,                6,272  NL                    11.19
                                                  mounts.
False killer whale...........  Rare............  Pelagic.........              N.A.  NL                        0
Killer whale.................  Common..........  Widely                 2,250-2,700  NL/EN \13\             1.66
                                                  distributed.
Short-finned pilot whale.....  Rare............  Pelagic, high-                 760  NL                        0
                                                  relief.
Harbor porpoise..............  Abundant........  Coastal and            \13\ 55,255  NL                    632.4
                                                  inland waters.
Dall's porpoise..............  Abundant........  Shelf, slope,               42,000  NL                    83.82
                                                  offshore.
          Pinnipeds
 
Northern fur seal............  Common..........  Pelagic,               \5\ 653,171  NL                    83.62
                                                  offshore.
California sea lion..........  Rare............  Coastal, shelf..           296,750  NL                        0
Steller sea lion.............  Common *........  Coastal, shelf..       \5\ 58,334-  T                     13.12
                                                                             72,223
Harbor seal..................  Abundant *......  Coastal.........       \14\ 24,732  NL                    292.3
Northern elephant seal.......  Common..........  Coastal, pelagic      \15\ 124,000  NL                    45.81
                                                  in migration.
----------------------------------------------------------------------------------------------------------------
N.A.--Data not available or species status was not assessed.
* In nearshore survey areas, rare elsewhere.
\1\ Abundance given for the California/Oregon/Washington or Eastern North Pacific stock (Carretta et al.
  2011a,b), unless otherwise stated.
\2\ Endangered Species Act: EN = Endangered, T = Threatened, DL = Delisted, NL = Not listed.
\3\ Density estimate as listed in Table 3 of the Observatory's applications. Refer to pg. 48 of application
  1, pg. 47 of application 2, and pg. 47 of application 3 for specific references.
\4\ Bering Sea (Wade et al. 2010).
\5\ Eastern North Pacific (Allen and Angliss 2011).
\6\ North Pacific (Barlow et al. 2009).
\7\ North Pacific (Wada 1976).
\8\ North Pacific (Tillman 1977).
\9\ North Pacific (Ohsumi and Wada 1974).
\10\ Eastern Temperate North Pacific (Whitehead 2002a).
\11\ All mesoplodont whales.
\12\ Offshore stock (Carretta et al. 2011a).
\13\ The Eastern North Pacific Southern Resident Stock of killer whales is listed as Endangered under the ESA.
\14\ Northern Oregon/Washington Coast and Northern California/Southern Oregon stocks.
\15\ Oregon/Washington Coastal Stock (Carretta et al. 2011a).

    Refer to Sections III and IV of the Observatory's applications for 
detailed information regarding the abundance and distribution, 
population status, and life history and behavior of these species and 
their occurrence in the proposed project area. The applications also 
present how the Observatory calculated the estimated densities for the 
marine mammals in the proposed survey area. We have reviewed these data 
and determined them to be the best available scientific information for 
the purposes of the proposed incidental harassment authorization.

[[Page 25972]]

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 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 is not 
an injury (Southall et al., 2007). Although we cannot exclude the 
possibility entirely, 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 in this document, we expect 
some behavioral disturbance, but we expect the disturbance to be 
localized.

Tolerance

    Studies on marine mammals' tolerance to sound in the natural 
environment are relatively rare. Richardson et al. (1995) defined 
tolerance as the occurrence of marine mammals in areas where they are 
exposed to human activities or manmade 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 (see Appendix B(5) in the Environmental Assessment). 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 
(Stone, 2003; Stone and Tasker, 2006; Moulton et al. 2005, 2006a; Weir 
2008a for sperm whales), (MacLean and Koski, 2005; Bain and Williams, 
2006 for Dall's porpoises). The relative responsiveness of baleen and 
toothed whales are quite variable.

Masking of Natural Sounds

    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).
    We expect that the masking effects of pulsed sounds (even from 
large arrays of airguns) on marine mammal calls and other natural 
sounds will be limited, although there are very few specific data on 
this. 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. We understand that some baleen and toothed whales continue 
calling in the presence of seismic pulses, and that some researchers 
have heard these calls 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 northeast Pacific 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 have 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). Several studies have reported hearing dolphins and 
porpoises calling while airguns were 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, we expect that the masking effects of seismic pulses 
will be minor, given the normally intermittent nature of seismic 
pulses. Refer to Appendix B(4) of the Foundation's Assessment for a 
more detailed discussion of masking effects on marine mammals.

Behavioral Disturbance

    Disturbance includes a variety of effects, including subtle to 
conspicuous changes in behavior, movement, and displacement. Reactions 
to sound, if any, depend on species, state of maturity, experience, 
current activity, reproductive state, time of day, and many other 
factors (Richardson et al., 1995; Wartzok et al., 2004; Southall et 
al., 2007; Weilgart, 2007). 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). 
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 
industrial sound. In most cases, this approach likely overestimates the 
numbers of marine mammals that would be affected in some biologically-
important manner.
    The sound criteria used to estimate how many marine mammals might 
be disturbed to some biologically-important degree by a seismic program 
are based primarily on behavioral observations of a few species. 
Scientists have conducted detailed studies on humpback, gray, bowhead 
(Balaena mysticetus), and sperm whales. There are less detailed data 
available for some other species of baleen whales, small toothed 
whales, and sea otters (Enhydra lutris), but for many species there are 
no data on responses to marine seismic surveys.
    Baleen Whales--Baleen whales generally tend to avoid operating 
airguns, but avoidance radii are quite variable (reviewed in Richardson 
et al., 1995). Whales are often reported to

[[Page 25973]]

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, 
as reviewed in Appendix B(5) of the Foundation's Assessment, 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 from the area. 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 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 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 four to 15 km (2.5 to 9.3 mi) 
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 summarized in Appendix 
B(5) of the Foundation's Assessment have shown that some species of 
baleen whales, notably bowhead and humpback whales, at times show 
strong avoidance at received levels lower than 160-170 dB re: 1 [mu]Pa.
    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, 20-in\3\ airgun with source 
level of 227 dB re: 1 [mu]Pa (p-p). In the 1998 study, the researchers 
documented that avoidance reactions began at five to eight km (3.1 to 
4.9 mi) from the array, and that those reactions kept most pods 
approximately three to four km (1.9 to 2.5 mi) from the operating 
seismic boat. In the 2000 study, McCauley et al. noted localized 
displacement during migration of four to five km (2.5 to 3.1 mi) by 
traveling pods and seven to 12 km (4.3 to 7.5 mi) 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 for humpback pods containing females, and at the mean closest 
point of approach distance, the received level was 143 dB re: 1 [mu]Pa. 
The initial avoidance response generally occurred at distances of five 
to eight km (3.1 to 4.9 mi) from the airgun array and two km (1.2 mi) 
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.
    Data collected by observers during several seismic surveys in the 
northwest Atlantic Ocean 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 versus non-seismic periods 
(Moulton and Holst, 2010).
    Humpback whales on their summer feeding grounds in Frederick Sound 
and Stephens Passage, 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 re: 1 [mu]Pa.
    Other 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). Although, the evidence for this 
was circumstantial and subject to alternative explanations (IAGC, 
2004). Also, the evidence was not consistent with subsequent results 
from the same area of Brazil (Parente et al., 2006), or with direct 
studies of humpbacks exposed to seismic surveys in other areas and 
seasons. After allowance for data from subsequent years, there was ``no 
observable direct correlation'' between strandings and seismic surveys 
(IWC, 2007: 236).
    There are no data on reactions of right whales to seismic surveys, 
but results from the closely-related bowhead whale show that their 
responsiveness can be quite variable depending on their activity 
(migrating versus feeding). Bowhead whales migrating west across the 
Alaskan Beaufort Sea in autumn, in particular, are unusually 
responsive, with substantial avoidance occurring out to distances of 20 
to 30 km (12.4 to 18.6 mi) from a medium-sized airgun source at 
received sound levels of approximately 120 to 130 dB re: 1 [mu]Pa 
(Miller et al., 1999; Richardson et al., 1999; see Appendix B(5) of the 
Foundation's Assessment). However, more recent research on bowhead 
whales (Miller et al., 2005; Harris et al., 2007) corroborates earlier 
evidence that, during the summer feeding season, bowheads are not as 
sensitive to seismic sources. Nonetheless, subtle but statistically 
significant changes in surfacing-respiration-dive cycles were evident 
upon statistical analysis (Richardson et al., 1986). In the summer, 
bowheads typically begin to show avoidance reactions at received levels 
of about 152 to 178 dB re: 1 [mu]Pa (Richardson et al., 1986, 1995; 
Ljungblad et al., 1988; Miller et al., 2005).
    A few studies have documented reactions of migrating and feeding 
(but not wintering) gray whales to seismic surveys. 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) root 
mean square basis, and that 10 percent of feeding whales interrupted 
feeding at received levels of 163 dB re: 1 [mu]Pa. 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).
    Occasionally, observers have seen various species of Balaenoptera 
(blue, sei, fin, and minke whales) in areas ensonified by airgun pulses 
(Stone, 2003; MacLean and Haley, 2004; Stone and Tasker, 2006), and 
have localized calls from blue and fin whales 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

[[Page 25974]]

(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) also observed localized avoidance by fin 
whales during seismic airgun events in the western Mediterranean Sea 
and adjacent Atlantic waters from 2006-2009. They reported that singing 
fin whales moved away from an operating airgun array for a time period 
that extended beyond the duration of the airgun activity.
    Ship-based monitoring studies of baleen whales (including blue, 
fin, sei, minke, and whales) in the northwest Atlantic found that 
overall, this group had lower sighting rates during seismic versus 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. We do not know 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, 2011). The western 
Pacific gray whale population did not appear 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, 2011).
    Toothed Whales--There is little systematic information available 
about reactions of toothed whales to noise pulses. There are few 
studies on toothed whales similar to the more extensive baleen whale/
seismic pulse work summarized earlier in Appendix B of the Foundation's 
Assessment. 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 protected species observers (observers) 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. The beluga whale (Delphinapterus leucas) is a species that 
(at least at times) shows long-distance avoidance of seismic vessels. 
Summer aerial surveys conducted in the southeastern Beaufort Sea 
reported that sighting rates of beluga whales were significantly lower 
at distances of 10 to 20 km (6.2 to 12.4 mi) from an operating airgun 
array compared to distances of 20 to 30 km (12.4 to 18.6 mi). Further, 
observers on seismic boats in that area have rarely reported sighting 
beluga whales (Miller et al., 2005; Harris et al., 2007).
    Captive bottlenose dolphins (Tursiops truncatus) and beluga whales 
exhibited changes in behavior when exposed to strong pulsed sounds 
similar in duration to those typically used in seismic surveys 
(Finneran et al., 2000, 2002, 2005). However, the animals tolerated 
high received levels of sound before exhibiting aversive behaviors.
    Results for porpoises depend on species. The limited available data 
suggest that harbor porpoises (Phocoena phocoena) show stronger 
avoidance of seismic operations than do Dall's porpoises (Stone, 2003; 
MacLean and Koski, 2005; Bain and Williams, 2006; Stone and Tasker, 
2006). Dall's porpoises seem relatively tolerant of airgun operations 
(MacLean and Koski, 2005; Bain and Williams, 2006), although they too 
have been observed to avoid large arrays of operating airguns 
(Calambokidis and Osmek, 1998; Bain and Williams, 2006). This apparent 
difference in responsiveness of these two porpoise species is 
consistent with their relative responsiveness to boat traffic and some 
other acoustic sources (Richardson et al., 1995; Southall et al., 
2007).
    Most studies of sperm whales exposed to airgun sounds indicate that 
the 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 (see Appendix B of the Foundation's Assessment for 
review). However, controlled exposure experiments in the Gulf of Mexico 
indicate that foraging behavior was altered upon exposure to airgun 
sound (Jochens et al., 2008; Miller et al., 2009; Tyack, 2009).
    There are almost no specific data on the behavioral reactions of 
beaked whales to seismic surveys. However, some northern bottlenose 
whales (Hyperoodon ampullatus) remained in the general area and 
continued to produce high-frequency clicks when exposed to sound pulses 
from distant seismic surveys (Gosselin and Lawson, 2004; Laurinolli and 
Cochrane, 2005; Simard et al., 2005). Most beaked whales tend to avoid 
approaching vessels of other types (e.g., Wursig et al., 1998). They 
may also dive for an extended period when approached by a vessel (e.g., 
Kasuya, 1986), although it is uncertain how much longer such dives may 
be as compared to dives by undisturbed beaked whales, which also are 
often quite long (Baird et al., 2006; Tyack et al., 2006). Based on a 
single observation, Aguilar-Soto et al. (2006) suggested that foraging 
efficiency of Cuvier's beaked whales (Ziphius

[[Page 25975]]

cavirostris) 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 
underway within the vicinity of the animals (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 the 
mysticetes, belugas, and harbor porpoises (See Appendix B of the 
Foundation's Assessment).
    Pinnipeds--Pinnipeds are not likely to show a strong avoidance 
reaction to the airgun array. Visual monitoring from seismic vessels 
has shown only slight (if any) avoidance of airguns by pinnipeds, and 
only slight (if any) changes in behavior, see Appendix B(5)(3) of the 
Foundation's Assessment. In the Beaufort Sea, some ringed seals avoided 
an area of 100 m (328 ft) to (at most) a few hundred meters around 
seismic vessels, but many seals remained within 100 to 200 m (328 to 
656 ft) of the trackline as the operating airgun array passed by (e.g., 
Harris et al., 2001; Moulton and Lawson, 2002; Miller et al., 2005). 
Ringed seal sightings averaged somewhat farther away from the seismic 
vessel when the airguns were operating than when they were not, but the 
difference was small (Moulton and Lawson, 2002). Similarly, in Puget 
Sound, sighting distances for harbor seals and California sea lions 
tended to be larger when airguns were operating (Calambokidis and 
Osmek, 1998). Previous telemetry work suggests that avoidance and other 
behavioral reactions may be stronger than evident to date from visual 
studies (Thompson et al., 1998).

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 et 
al., 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 (Southall et al., 2007).
    Researchers have studied temporary threshold shift in certain 
captive odontocetes and pinnipeds exposed to strong sounds (reviewed in 
Southall et al., 2007). However, there has been no specific 
documentation of temporary threshold shift let alone permanent hearing 
damage, i.e., permanent threshold shift, in free-ranging marine mammals 
exposed to sequences of airgun pulses during realistic field 
conditions.
    Temporary Threshold Shift--This is the mildest form of hearing 
impairment that can occur during exposure to a strong sound (Kryter, 
1985). While experiencing temporary threshold shift, the hearing 
threshold rises and a sound must be stronger in order to be heard. At 
least in terrestrial mammals, temporary threshold shift can last from 
minutes or hours to (in cases of strong shifts) days. For sound 
exposures at or somewhat above the temporary threshold shift threshold, 
hearing sensitivity in both terrestrial and marine mammals recovers 
rapidly after exposure to the noise ends. There are few data on sound 
levels and durations necessary to elicit mild temporary threshold shift 
for marine mammals, and none of the published data focus on temporary 
threshold shift elicited by exposure to multiple pulses of sound. 
Southall et al. (2007) summarizes available data on temporary threshold 
shift in marine mammals. Table 2 (introduced earlier in this document) 
presents the estimated distances from the Langseth's airguns at which 
the received energy level (per pulse, flat-weighted) would be greater 
than or equal to 180 or 190 dB re: 1 [micro]Pa.
    Researchers have derived temporary threshold shift information for 
odontocetes from studies on the bottlenose dolphin and beluga. For the 
one harbor porpoise tested, the received level of airgun sound that 
elicited onset of temporary threshold shift was lower (Lucke et al., 
2009). If these results from a single animal are representative, it is 
inappropriate to assume that onset of temporary threshold shift occurs 
at similar received levels in all odontocetes (cf. Southall et al., 
2007). Some cetaceans apparently can incur temporary threshold shift at 
considerably lower sound exposures than are necessary to elicit 
temporary threshold shift 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 temporary threshold 
shift. 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 temporary threshold shift onset may also be higher in 
baleen whales (Southall et al., 2007). For this proposed study, the 
Observatory expects no cases of temporary threshold shift given the low 
abundance of baleen whales in the planned study area at the time of the 
survey, and the strong likelihood that baleen whales would avoid the 
approaching airguns (or vessel) before being exposed to levels high 
enough for temporary threshold shift to occur.
    In pinnipeds, researchers have not measured temporary threshold 
shift thresholds associated with exposure to brief pulses (single or 
multiple) of underwater sound. Initial evidence from more prolonged 
(non-pulse) exposures suggested that some pinnipeds (harbor seals in 
particular) incur temporary threshold shift at somewhat lower received 
levels than do small odontocetes exposed for similar durations (Kastak 
et al., 1999, 2005; Ketten et al., 2001). The indirectly estimated 
temporary threshold shift threshold for pulsed sounds would be 
approximately 181 to 186 dB re: 1 [mu]Pa

[[Page 25976]]

(Southall et al., 2007), or a series of pulses for which the highest 
sound exposure level values are a few decibels lower. Corresponding 
values for California sea lions and northern elephant seals are likely 
to be higher (Kastak et al., 2005).
    Permanent Threshold Shift--When permanent threshold shift 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 permanent threshold shift 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 temporary threshold shift, there has been further speculation 
about the possibility that some individuals occurring very close to 
airguns might incur permanent threshold shift (e.g., Richardson et al., 
1995, p. 372ff; Gedamke et al., 2008). Single or occasional occurrences 
of mild temporary threshold shift are not indicative of permanent 
auditory damage, but repeated or (in some cases) single exposures to a 
level well above that causing temporary threshold shift onset might 
elicit permanent threshold shift.
    Relationships between temporary threshold shift and permanent 
threshold shift thresholds have not been studied in marine mammals, but 
are assumed to be similar to those in humans and other terrestrial 
mammals. Permanent threshold shift might occur at a received sound 
level at least several decibels above that inducing mild temporary 
threshold shift if the animal were exposed to strong sound pulses with 
rapid rise times--see Appendix B(6) of the Foundation's Assessment. 
Based on data from terrestrial mammals, a precautionary assumption is 
that the permanent threshold shift threshold for impulse sounds (such 
as airgun pulses as received close to the source) is at least six 
decibels higher than the temporary threshold shift threshold on a peak-
pressure basis, and probably greater than six decibels (Southall et 
al., 2007).
    Given the higher level of sound necessary to cause permanent 
threshold shift as compared with temporary threshold shift, it is 
considerably less likely that permanent threshold shift 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-The association of 
strandings of beaked whales with naval exercises involving mid-
frequency active sonar and, in one case, an Observatory's seismic 
survey (Malakoff, 2002; Cox et al., 2006), has raised the possibility 
that beaked whales exposed to strong ``pulsed'' sounds may be 
especially susceptible to injury and/or behavioral reactions that can 
lead to stranding (e.g., Hildebrand, 2005; Southall et al., 2007). 
Appendix B (6) of the Foundation's Assessment provides additional 
details.
    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 increasing 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. However, the evidence for this 
remains circumstantial and associated with exposure to naval mid-
frequency sonar,

[[Page 25977]]

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 two 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 assume that there is a direct connection between the 
effects of military sonar and seismic surveys on marine mammals. 
However, evidence that sonar signals can, in special circumstances, 
lead (at least indirectly) to physical damage and mortality (e.g., 
Balcomb and Claridge, 2001; NOAA and USN, 2001; Jepson et al., 2003; 
Fern[aacute]ndez et al., 2004, 2005; Hildebrand 2005; Cox et al., 2006) 
suggests that caution is warranted when dealing with exposure of marine 
mammals to any high-intensity ``pulsed'' 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, 
two Cuvier's beaked whales stranded in the Gulf of California, Mexico 
while the Observatory's R/V Maurice Ewing had been 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). We anticipate no injuries of beaked whales 
during the proposed study because of:
    (1) The 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 the 
Observatory 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 
and some odontocetes, are especially unlikely to incur non-auditory 
physical effects.

Potential Effects of Other Acoustic Devices

Multibeam Echosounder
    The Observatory 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 two 
to 15 ms once every five to 20 s, depending on water depth. Most of the 
energy in the sound pulses emitted by this echosounder is at 
frequencies near 12 kHz, and the maximum source level is 242 dB re: 1 
[mu]Pa. 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 (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 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 vessel (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 an 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 temporary threshold 
shift.
    Navy sonars 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 echosounder. The area of possible influence of the 
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 the Observatory'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 
the animal. The following section outlines possible effects of an 
echosounder on marine mammals.
    Masking--Marine mammal communications will not be masked 
appreciably by the echosounder's 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 echosounder's 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

[[Page 25978]]

no dispersal by pilot whales (Globicephala melas) (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 (Frankel, 2005). When a 38-kHz echosounder and a 
150-kHz acoustic Doppler current profiler were transmitting during 
studies in the eastern Tropical Pacific Ocean, 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-s tonal signals at frequencies similar to 
those that will be emitted by the Observatory's echosounder, 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 an 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 echosounder 
proposed for use by the Observatory is quite different than sonar used 
for navy operations. The echosounder's pulse duration is very short 
relative to the naval sonar. Also, at any given location, an individual 
marine mammal would be in the echosounder's beam 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 echosounder relative to that from naval sonar.
    Based upon the best available science, we believe that the brief 
exposure of marine mammals to one pulse, or small numbers of signals, 
from the echosounder is not likely to result in the harassment of 
marine mammals.

Sub-Bottom Profiler

    The Observatory will also operate a sub-bottom profiler from the 
source vessel during the proposed survey. The profiler's sounds are 
very short pulses, occurring for one to four ms once every second. Most 
of the energy in the sound pulses emitted by the profiler is at 3.5 
kHz, and the beam is directed downward. The sub-bottom profiler on the 
Langseth has a maximum source level of 222 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 profiler more powerful than that on the 
Langseth--if the animal was in the area, it would have to pass the 
transducer at close range and in order to be subjected to sound levels 
that could cause temporary threshold shift.
    Masking--Marine mammal communications will not be masked 
appreciably by the profiler's 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 
profiler's 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 profiler 
are likely to be similar to those for other pulsed sources if received 
at the same levels. However, the pulsed signals from the profiler are 
considerably weaker than those from the 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 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 profiler operates 
simultaneously with other higher-power acoustic sources. 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 profiler. Based upon the best available science, we believe 
that the brief exposure of marine mammals to signals from the profiler 
is not likely to result in the harassment of marine mammals.

Potential Effects of 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 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 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

[[Page 25979]]

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' reactions varied when exposed to vessel noise and 
traffic. In some cases, naive beluga whales exhibited rapid swimming 
from ice-breaking vessels up to 80 km (49.7 mi) away, and showed 
changes in surfacing, breathing, diving, and group composition in the 
Canadian high Arctic where vessel traffic is rare (Finley et al., 
1990). In other cases, beluga whales were more tolerant of vessels, but 
responded differentially to certain vessels and operating 
characteristics by reducing their calling rates (especially older 
animals) in the St. Lawrence River where vessel traffic is common 
(Blane and Jaakson, 1994). In Bristol Bay, Alaska, beluga whales 
continued to feed when surrounded by fishing vessels and resisted 
dispersal even when purposefully harassed (Fish and Vania, 1971).
    In reviewing more than 25 years of whale observation data, Watkins 
(1986) concluded that whale reactions to vessel traffic were ``modified 
by their previous experience and current activity: habituation often 
occurred rapidly, attention to other stimuli or preoccupation with 
other activities sometimes overcame their interest or wariness of 
stimuli.'' Watkins noticed that over the years of exposure to ships in 
the Cape Cod area, minke whales changed from frequent positive interest 
(e.g., approaching vessels) to generally uninterested reactions; fin 
whales changed from mostly negative (e.g., avoidance) to uninterested 
reactions; right whales apparently continued the same variety of 
responses (negative, uninterested, and positive responses) with little 
change; and humpbacks dramatically changed from mixed responses that 
were often negative to reactions that were often strongly positive. 
Watkins (1986) summarized that ``whales near shore, even in regions 
with low vessel traffic, generally have become less wary of boats and 
their noises, and they have appeared to be less easily disturbed than 
previously. In particular locations with intense shipping and repeated 
approaches by boats (such as the whale-watching areas of Stellwagen 
Bank), more and more whales had positive reactions to familiar vessels, 
and they also occasionally approached other boats and yachts in the 
same ways.''
    Although the radiated sound from the Langseth will be audible to 
marine mammals over a large distance, it is unlikely that animals will 
respond behaviorally (in a manner that we would consider MMPA 
harassment) 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, we do not expect the Langseth's movements to 
result in Level B harassment.

Vessel Strike

    Ship strikes of cetaceans can cause major wounds, which may lead to 
the death of the animal. An animal at the surface could be struck 
directly by a vessel, a surfacing animal could hit the bottom of a 
vessel, or an animal just below the surface could be cut by a vessel's 
propeller. The severity of injuries typically depends on the size and 
speed of the vessel (Knowlton and Kraus, 2001; Laist et al., 2001; 
Vanderlaan and Taggart, 2007).
    The most vulnerable marine mammals are those that spend extended 
periods of time at the surface in order to restore oxygen levels within 
their tissues after deep dives (e.g., the sperm whale). In addition, 
some baleen whales, such as the North Atlantic right whale, seem 
generally unresponsive to vessel sound, making them more susceptible to 
vessel collisions (Nowacek et al., 2004). These species are primarily 
large, slow moving whales. Smaller marine mammals (e.g., bottlenose 
dolphin) move quickly through the water column and are often seen 
riding the bow wave of large ships. Marine mammal responses to vessels 
may include avoidance and changes in dive pattern (NRC, 2003).
    An examination of all known ship strikes from all shipping sources 
(civilian and military) indicates vessel speed is a principal factor in 
whether a vessel strike results in death (Knowlton and Kraus, 2001; 
Laist et al., 2001; Jensen and Silber, 2003; Vanderlaan and Taggart, 
2007). In assessing records in which vessel speed was known, Laist et 
al. (2001) found a direct relationship between the occurrence of a 
whale strike and the speed of the vessel involved in the collision. The 
authors concluded that most deaths occurred when a vessel was traveling 
in excess of 14.9 mph (24.1 km/hr;13 kts).
    The Observatory's proposed operation of one 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 Langseth's 
slow operational speed, which is typically 4.6 kts (8.5 km/h; 5.3 mph). 
Outside of operations, the Langseth's cruising speed would be 
approximately 11.5 mph (18.5 km/h; 10 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 Langseth has a number of other advantages for 
avoiding ship strikes as compared to most commercial merchant vessels, 
including the following: the Langseth's bridge offers good visibility 
to visually monitor for marine mammal presence; observers posted during 
operations scan the ocean for marine mammals and must report visual 
alerts of marine mammal presence to crew; and the observers receive 
extensive training that covers the fundamentals of visual observing for 
marine mammals and information about marine mammals and their 
identification at sea.
    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 
adverse 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 reversible 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, previously discussed in this notice. The next section 
discusses the potential impacts of anthropogenic sound sources

[[Page 25980]]

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 
populations is limited (see Appendix D of the Foundation's Assessment). 
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.
    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 then 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 (see Appendix D of the Foundation's Assessment). 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 we 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 temporary threshold shift 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 
temporary threshold shift (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 9 
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 
(i.e., 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).
    Some studies have reported, some equivocally, that mortality of 
fish, fish eggs, or larvae can occur close to seismic sources 
(Kostyuchenko, 1973; Dalen and Knutsen, 1986; Booman et al., 1996; 
Dalen et al., 1996). Some of the reports claimed seismic effects from 
treatments quite different from actual seismic survey sounds or even 
reasonable surrogates. However, Payne et al. (2009) reported no 
statistical differences in mortality/morbidity between control and 
exposed groups of capelin eggs or monkfish larvae. Saetre and Ona 
(1996) applied a worst-case scenario, mathematical model to investigate 
the effects of seismic energy on fish eggs and larvae. They concluded 
that mortality rates caused by exposure to seismic surveys are so low, 
as compared to natural mortality rates, that the impact of seismic 
surveying on recruitment to a fish stock must be regarded as 
insignificant.
    Physiological Effects--Physiological effects refer to cellular and/
or biochemical responses of fish to acoustic stress. Such stress 
potentially could affect fish populations by increasing mortality or 
reducing reproductive success. Primary and secondary stress responses 
of fish after exposure to seismic survey sound appear to be temporary 
in all studies done to date (Sverdrup et al., 1994; Santulli et al., 
1999; McCauley et al., 2000a,b). The periods necessary for the 
biochemical changes to return to normal are variable and depend on 
numerous aspects of the biology of the species and

[[Page 25981]]

of the sound stimulus (see Appendix D of the Foundation's Assessment).
    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.
    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 Fisheries

    It is possible that the Langseth's streamer may become entangled 
with various types of fishing gear. The Observatory will employ 
avoidance tactics as necessary to prevent conflict. It is not expected 
that the Observatory's operations will have a significant impact on 
fisheries in the western Pacific Ocean. Nonetheless, the Observatory 
will minimize the potential to have a negative impact on the fisheries 
by avoiding areas where fishing is actively underway.
    There is general concern about potential adverse effects of seismic 
operations on fisheries, namely a potential reduction in the 
catchability of fish involved in fisheries. Although reduced catch 
rates have been observed in some marine fisheries during seismic 
testing, in a number of cases the findings are confounded by other 
sources of disturbance (Dalen and Raknes, 1985; Dalen and Knutsen, 
1986; Lokkeborg, 1991; Skalski et al., 1992; Engas et al., 1996). In 
other airgun experiments, there was no change in catch per unit effort 
of fish when airgun pulses were emitted, particularly in the immediate 
vicinity of the seismic survey (Pickett et al., 1994; La Bella et al., 
1996). For some species, reductions in catch may have resulted from a 
change in behavior of the fish, (e.g., a change in vertical or 
horizontal distribution), as reported in Slotte et al. (2004).

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; see also 
Appendix E of the Foundation's Assessment).
    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 in Appendix E of the Foundation's Assessment.
    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.
    Andre et al. (2011) exposed four cephalopod species (Loligo 
vulgaris, Sepia officinalis, Octopus vulgaris, and Ilex coindetii) to 
two hours of continuous sound from 50 to 400 Hz at 157  5 
dB re: 1 [mu]Pa. They reported lesions to the sensory hair cells of the 
statocysts of the exposed animals that increased in severity with time, 
suggesting that cephalopods are particularly sensitive to low-frequency 
sound. The received sound pressure level was 157 v 5 dB re: 1 [mu]Pa, 
with peak levels at 175 dB re: 1 [mu]Pa. As in the McCauley et al. 
(2003) paper on sensory hair cell damage in pink snapper as a result of 
exposure to seismic sound, the cephalopods were subjected to higher 
sound levels than they would be under natural conditions, and they were 
unable to swim away from the sound source.
    Physiological Effects--Physiological effects refer mainly to 
biochemical responses by marine invertebrates to acoustic stress. Such 
stress potentially could affect invertebrate populations by increasing 
mortality or reducing reproductive success. Primary and secondary 
stress responses (i.e., changes in haemolymph levels of enzymes, 
proteins, etc.) of crustaceans have been noted several days or months 
after exposure to seismic survey sounds (Payne et al., 2007). The 
periods necessary for these biochemical changes to return to normal are 
variable and depend on numerous aspects of the

[[Page 25982]]

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 under section 
101(a)(5)(D) of the Marine Mammal Protection Act, we must set forth the 
permissible methods of taking pursuant to such activity, and other 
means of effecting the least practicable adverse 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.
    The Observatory has based the mitigation measures which they will 
implement during the proposed seismic survey, on the following:
    (1) Protocols used during previous seismic research cruises as 
approved by us;
    (2) Previous incidental harassment authorizations applications and 
authorizations that we have approved and authorized; 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, the Observatory and/or its designees 
would implement the following mitigation measures for marine mammals:
    (1) Proposed exclusion zones;
    (2) Power down procedures;
    (3) Shutdown procedures; and
    (4) Ramp-up procedures.
    Proposed Exclusion Zones--The Observatory uses safety radii to 
designate exclusion 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 36-airgun array and a single airgun. The 180-dB and 
190-dB level shutdown criteria are applicable to cetaceans and 
pinnipeds, respectively, as specified by us (2000). The Observatory 
used these levels to establish the exclusion zones.
    If the protected species visual observer detects marine mammal(s) 
within or about to enter the appropriate exclusion zone, the Langseth 
crew will immediately power down the airgun array, or perform a 
shutdown if necessary (see Shut-down Procedures).
    Power Down Procedures--A power down involves decreasing the number 
of airguns in use such that the radius of the 180-dB (or 190-dB) zone 
is smaller to the extent that marine mammals are no longer within or 
about to enter the exclusion zone. A power down of the airgun array can 
also occur when the vessel is moving from one seismic line to another. 
During a power down for mitigation, the Observatory will operate one 
airgun (40 in\3\). The continued operation of one airgun is intended to 
alert marine mammals to the presence of the seismic vessel in the area. 
In contrast, a shutdown occurs when the Langseth suspends all airgun 
activity.
    If the observer detects a marine mammal outside the exclusion zone 
and the animal is likely to enter the zone, the crew will power down 
the airguns to reduce the size of the 180-dB exclusion zone before the 
animal enters that zone.
    Likewise, if a mammal is already within the zone when first 
detected, the crew will power-down the airguns immediately. During a 
power down of the airgun array, the crew will operate a single 40-in\3\ 
airgun which has a smaller exclusion zone. If the observer detects a 
marine mammal within or near the smaller exclusion zone around the 
airgun (Table 2), the crew will shut down the single airgun (see next 
section).
    Shutdown Procedures--The Langseth crew will shutdown the operating 
airgun(s) if a marine mammal is seen within or approaching the 
exclusion zone for the single airgun. The crew will implement a 
shutdown:
    (1) If an animal enters the exclusion zone of the single airgun 
after the crew has initiated a power down; or
    (2) If an animal is initially seen within the exclusion zone of the 
single airgun when more than one airgun (typically the full airgun 
array) is operating.
    Considering the conservation status for north Pacific right whales, 
the Langseth crew will shutdown the airgun(s) immediately in the 
unlikely event that this species is observed, regardless of the 
distance from the vessel.

Resuming Airgun Operations After a Power Down

    Following a power-down, the Langseth crew will not resume full 
airgun activity until the marine mammal has cleared the 180-dB 
exclusion zone (see Table 2). The observers will consider the animal to 
have cleared the exclusion zone if:
     The observer has visually observed the animal leave the 
exclusion zone, or
     An observer has not sighted the animal within the 
exclusion zone for 15 minutes for species with shorter dive durations 
(i.e., small odontocetes or pinnipeds), or 30 minutes for species with 
longer dive durations (i.e., mysticetes and large odontocetes, 
including sperm, pygmy sperm, dwarf sperm, and beaked whales); or
     The vessel has transited outside the original 180-dB 
exclusion zone after an 8-minute wait period. This period is based on 
the 180-dB exclusion zone for the 36-airgun array (940 m) towed at a 
depth of 9 m (29.5 ft) in relation to the average speed of the Langseth 
while operating the airguns (8.5 km/h; 5.3 mph).
    The Langseth crew will resume operating the airguns at full power 
after 15 minutes of sighting any species with short dive durations 
(i.e., small odontocetes or pinnipeds). Likewise, the crew will resume 
airgun operations at full power after 30 minutes of sighting any 
species with longer dive durations (i.e., mysticetes and large 
odontocetes, including sperm, pygmy sperm, dwarf sperm, and beaked 
whales).
    Because the vessel has transited 1.13 km (3,707 feet) away from the 
vicinity of the original sighting during the 8-minute period, 
implementing ramp-up procedures for the full array after an extended 
power down (i.e., transiting for an additional 35 minutes from the 
location of initial sighting) would not meaningfully increase the 
effectiveness of observing marine mammals approaching or entering the 
exclusion zone for the full source level and would

[[Page 25983]]

not further minimize the potential for take. The Langseth's observers 
are continually monitoring the exclusion zone for the full source level 
while the mitigation airgun is firing. On average, observers can 
observe to the horizon (10 km; 6.2 mi) from the height of the 
Langseth's observation deck and should be able to say with a reasonable 
degree of confidence whether a marine mammal would be encountered 
within this distance before resuming airgun operations at full power.

Resuming Airgun Operations After a Shutdown

    Following a shutdown, the Langseth crew will initiate a ramp-up 
with the smallest airgun in the array (40-in\3\). The crew will turn on 
additional airguns in a sequence such that the source level of the 
array will increase in steps not exceeding 6 dB per five-minute period 
over a total duration of approximately 30 minutes. During ramp-up, the 
observers will monitor the exclusion zone, and if he/she sights a 
marine mammal, the Langseth crew will implement a power down or 
shutdown as though the full airgun array were operational.
    During periods of active seismic operations, there are occasions 
when the Langseth crew will need to temporarily shut down the airguns 
due to equipment failure or for maintenance. In this case, if the 
airguns are inactive longer than eight minutes, the crew will follow 
ramp-up procedures for a shutdown described earlier and the observers 
will monitor the full exclusion zone and will implement a power down or 
shutdown if necessary.
    If the full exclusion zone is not visible to the observer for at 
least 30 minutes prior to the start of operations in either daylight or 
nighttime, the Langseth crew will not commence ramp-up unless at least 
one airgun (40-in\3\ or similar) has been operating during the 
interruption of seismic survey operations. Given these provisions, it 
is likely that the vessel's crew will not ramp up the airgun array from 
a complete shutdown at night or in thick fog, because the outer part of 
the zone for that array will not be visible during those conditions.
    If one airgun has operated during a power down period, ramp-up to 
full power will be permissible at night or in poor visibility, on the 
assumption that marine mammals will be alerted to the approaching 
seismic vessel by the sounds from the single airgun and could move 
away. The vessel's crew will not initiate 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.
    We have carefully evaluated the applicant's proposed mitigation 
measures and have considered a range of other measures in the context 
of ensuring that we have prescribed the means of effecting the least 
practicable adverse impact on the affected marine mammal species and 
stocks and their habitat. Our 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, we expect that 
the successful implementation of the measure would 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 our evaluation of the Observatory's proposed measures, as 
well as other measures considered by us or recommended by the public, 
we have preliminarily determined that the mitigation measures provide 
the means of effecting the least practicable adverse impacts on marine 
mammals 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 incidental take authorization for an activity, 
section 101(a)(5)(D) of the Marine Mammal Protection Act states that we 
must set forth ``requirements pertaining to the monitoring and 
reporting of such taking.'' The Act's implementing regulations at 50 
CFR 216.104(a)(13) indicate that requests for an authorization must 
include the suggested means of accomplishing the necessary monitoring 
and reporting that will result in increased knowledge of the species 
and our expectations of the level of taking or impacts on populations 
of marine mammals present in the action area.

Proposed Monitoring

    The Observatory proposes to sponsor marine mammal monitoring during 
the present project, in order to implement the mitigation measures that 
require real-time monitoring, and to satisfy the monitoring 
requirements of the incidental harassment authorization. We describe 
the Observatory's Monitoring Plan below this section. The Observatory 
understands that this monitoring plan will be subject to review by us, 
and that we may require refinements to the plan. The Observatory has 
planned the monitoring work as a self-contained project independent of 
any other related monitoring projects that may occur in the same 
regions at the same time. Further, the Observatory would discuss 
coordination of its monitoring program with any other related work by 
other groups working in the same area, if practical.

Vessel-Based Visual Monitoring

    The Observatory will position observers aboard the seismic source 
vessel to watch for marine mammals near the vessel during daytime 
airgun operations and during any start-ups at night. Observers 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 
shutdown (i.e., greater than approximately eight minutes for this 
proposed cruise). When feasible, the observers 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 the 
observations, the Langseth will power down or shutdown the airguns when 
marine mammals are observed within or about to enter a designated 
exclusion zone which is a region in which a possibility exists of 
adverse effects on animal hearing or other physical effects.
    During seismic operations, at least four protected species 
observers will be aboard the Langseth. The Observatory will appoint the 
observers with our concurrence. They will conduct observations during 
ongoing daytime operations and nighttime ramp-ups of the airgun array. 
During the majority of seismic operations, two observers will be on 
duty from the observation tower to monitor marine mammals near the 
seismic vessel. Using two observers will increase the effectiveness of 
detecting animals near the source vessel. However, during mealtimes and 
bathroom breaks, it is sometimes difficult to have two observers on 
effort, but at least one observer will be on watch during bathroom 
breaks and mealtimes. Observers will be on duty in shifts of no longer 
than four hours in duration.
    Two observers will also be on visual watch during all nighttime 
ramp-ups of the seismic airguns. A third observer will monitor the 
passive acoustic monitoring equipment 24 hours a day to detect 
vocalizing marine mammals present in the action area. In summary, a 
typical daytime cruise would have

[[Page 25984]]

scheduled two observers (visual) on duty from the observation tower, 
and a observer (acoustic) on the passive acoustic monitoring system. 
Before the start of the seismic survey, the Observatory will instruct 
the vessel's crew to assist in detecting marine mammals and 
implementing mitigation requirements.
    The Langseth is a suitable platform for marine mammal observations. 
When stationed on the observation platform, the eye level will be 
approximately 21.5 m (70.5 ft) above sea level, and the observer will 
have a good view around the entire vessel. During daytime, the 
observers will scan the area around the vessel systematically with 
reticle binoculars (e.g., 7 x 50 Fujinon), Big-eye binoculars (25 x 
150), and with the naked eye. During darkness, night vision devices 
will be available (ITT F500 Series Generation 3 binocular-image 
intensifier or equivalent), when required. Laser range-finding 
binoculars (Leica LRF 1200 laser rangefinder or equivalent) will be 
available to assist with distance estimation. Those are useful in 
training observers to estimate distances visually, but are generally 
not useful in measuring distances to animals directly; that is done 
primarily with the reticles in the binoculars.
    When the observers see marine mammals within or about to enter the 
designated exclusion zone, the Langseth will immediately power down or 
shutdown the airguns if necessary. The observer(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 observer has confirmed that the animal has left the 
zone, or if not observed after 15 minutes for species with shorter dive 
durations (small odontocetes and pinnipeds) or 30 minutes for species 
with longer dive durations (mysticetes and large odontocetes, including 
sperm, pygmy sperm, dwarf sperm, killer, and beaked whales).

Passive Acoustic Monitoring

    Passive acoustic monitoring will complement the visual monitoring 
program, when practicable. Visual monitoring typically is not effective 
during periods of poor visibility or at night, and even with good 
visibility, is unable to detect marine mammals when they are below the 
surface or beyond visual range. Acoustical monitoring can be used in 
conjunction with visual observations to improve detection, 
identification, and localization of cetaceans. The acoustic monitoring 
will serve to alert visual observers (if on duty) when vocalizing 
cetaceans are detected. It is only useful when marine mammals call, but 
it can be effective either by day or by night, and does not depend on 
good visibility. The acoustic observer will monitor the system in real 
time so that he/she can advise the visual observers if they acoustic 
detect cetaceans. When the acoustic observer determines the bearing 
(primary and mirror-image) to calling cetacean(s), he/she alert the 
visual observer to help him/her sight the calling animal(s).
    The passive acoustic monitoring system consists of hardware (i.e., 
hydrophones) and software. The ``wet end'' of the system consists of a 
towed hydrophone array that is connected to the vessel by a tow cable. 
The tow cable is 250 m (820.2 ft) long, and the hydrophones are fitted 
in the last 10 m (32.8 ft) of cable. A depth gauge is attached to the 
free end of the cable, and the cable is typically towed at depths less 
than 20 m (65.6 ft). The Langseth crew will deploy the array from a 
winch located on the back deck. A deck cable will connect the tow cable 
to the electronics unit in the main computer lab where the acoustic 
station, signal conditioning, and processing system will be located. 
The acoustic signals received by the hydrophones are amplified, 
digitized, and then processed by the Pamguard software. The system can 
detect marine mammal vocalizations at frequencies up to 250 kHz.
    As described earlier, one acoustic observer, an expert 
bioacoustician with primary responsibility for the passive acoustic 
monitoring system will be aboard the Langseth in addition to the four 
visual observers. The acoustic observer will monitor the towed 
hydrophones 24 hours per day during airgun operations and during most 
periods when the Langseth is underway while the airguns are not 
operating. However, passive acoustic monitoring may not be possible if 
damage occurs to both the primary and back-up hydrophone arrays during 
operations. The primary passive acoustic monitoring streamer on the 
Langseth is a digital hydrophone streamer. Should the digital streamer 
fail, back-up systems should include an analog spare streamer and a 
hull-mounted hydrophone.
    One acoustic observer will monitor the acoustic detection system by 
listening to the signals from two channels via headphones and/or 
speakers and watching the real-time spectrographic display for 
frequency ranges produced by cetaceans. The observer monitoring the 
acoustical data will be on shift for one to six hours at a time. The 
other observers will rotate as an acoustic observer, although the 
expert acoustician will be on passive acoustic monitoring duty more 
frequently.
    When the acoustic observer detects a vocalization while visual 
observations are in progress, the acoustic observer on duty will 
contact the visual observer immediately, to alert him/her to the 
presence of cetaceans (if they have not already been seen), so that the 
vessel's crew can initiate a power down or shutdown, if required. The 
observer will enter the information regarding the call into a database. 
Data entry will include an acoustic encounter identification number, 
whether it was linked with a visual sighting, date, time when first and 
last heard and whenever any additional information was recorded, 
position and water depth when first detected, bearing if determinable, 
species or species group (e.g., unidentified dolphin, sperm whale), 
types and nature of sounds heard (e.g., clicks, continuous, sporadic, 
whistles, creaks, burst pulses, strength of signal, etc.), and any 
other notable information. The acoustic detection can also be recorded 
for further analysis.

Observer Data and Documentation

    Observers 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. They will use the data 
to estimate numbers of animals potentially `taken' by harassment (as 
defined in the MMPA). They will also provide information needed to 
order a power down or shut down of the airguns when a marine mammal is 
within or near the exclusion zone.
    When an observer makes a sighting, they will record the following 
information:
    1. Species, group size, age/size/sex categories (if determinable), 
behavior when first sighted and after initial sighting, heading (if 
consistent), bearing and distance from seismic vessel, sighting cue, 
apparent reaction to the airguns or vessel (e.g., none, avoidance, 
approach, paralleling, etc.), and behavioral pace.
    2. Time, location, heading, speed, activity of the vessel, sea 
state, visibility, and sun glare.
    The observer will record the data listed under (2) 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.
    Observers will record all observations and power downs or shutdowns 
in a standardized format and will enter data into an electronic 
database. The

[[Page 25985]]

observers will verify the accuracy of the data entry by computerized 
data validity checks as the data are entered and by subsequent manual 
checking of the database. These procedures will allow the preparation 
of initial summaries of data 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:
    1. The basis for real-time mitigation (airgun power down or 
shutdown).
    2. Information needed to estimate the number of marine mammals 
potentially taken by harassment, which the Observatory must report to 
the Office of Protected Resources.
    3. Data on the occurrence, distribution, and activities of marine 
mammals and turtles in the area where the Observatory will conduct the 
seismic study.
    4. Information to compare the distance and distribution of marine 
mammals and turtles relative to the source vessel at times with and 
without seismic activity.
    5. Data on the behavior and movement patterns of marine mammals 
detected during non-active and active seismic operations.

Proposed Reporting

    The Observatory will submit a report to us and to the Foundation 
within 90 days after the end of the cruise. The report will describe 
the operations that were conducted and sightings of marine mammals and 
turtles near the operations. The report will provide full documentation 
of methods, results, and interpretation pertaining to all monitoring. 
The 90-day report will summarize the dates and locations of seismic 
operations, and all marine mammal sightings (dates, times, locations, 
activities, associated seismic survey activities). 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.
    In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by the 
authorization (if issued), such as an injury (Level A harassment), 
serious injury or mortality (e.g., ship-strike, gear interaction, and/
or entanglement), the Observatory shall immediately cease the specified 
activities and immediately report the incident to the Incidental Take 
Program Supervisor, Permits and Conservation Division, Office of 
Protected Resources, NMFS, at 301-427-8401 and/or by email to 
Jolie.Harrison@noaa.gov and ITP.Cody@noaa.gov and to the Northwest 
Regional Stranding Coordinator at (206) 526-6550 
(Brent.Norberg@noaa.gov). 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).
    The Observatory shall not resume its activities until we are able 
to review the circumstances of the prohibited take. We shall work with 
the Observatory to determine what is necessary to minimize the 
likelihood of further prohibited take and ensure Marine Mammal 
Protection Act compliance. The Observatory may not resume their 
activities until notified by us via letter, email, or telephone.
    In the event that the Observatory discovers an injured or dead 
marine mammal, and the lead visual observer 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 we describe in 
the next paragraph), the Observatory will immediately report the 
incident to the Incidental Take Program Supervisor, Permits and 
Conservation Division, Office of Protected Resources, at 301-427-8401 
and/or by email to Jolie.Harrison@noaa.gov and ITP.Cody@noaa.gov and to 
the Northwest Regional Stranding Coordinator at (206) 526-6550 
(Brent.Norberg@noaa.gov). The report must include the same information 
identified in the paragraph above this section. Activities may continue 
while we review the circumstances of the incident. We will work with 
the Observatory to determine whether modifications in the activities 
are appropriate.
    In the event that the Observatory discovers an injured or dead 
marine mammal, and the lead visual observer determines that the injury 
or death is not associated with or related to the authorized activities 
(e.g., previously wounded animal, carcass with moderate to advanced 
decomposition, or scavenger damage), the Observatory will report the 
incident to the Incidental Take Program Supervisor, Permits and 
Conservation Division, Office of Protected Resources, at 301-427-8401 
and/or by email to Jolie.Harrison@noaa.gov and ITP.Cody@noaa.gov and 
the Northwest Regional Stranding Coordinator at (206) 526-6550 
(Brent.Norberg@noaa.gov), within 24 hours of the discovery. The 
Observatory will provide photographs or video footage (if available) or 
other documentation of the stranded animal sighting to us.

Estimated Take by Incidental Harassment

    Except with respect to certain activities not pertinent here, the 
Marine Mammal Protection Act 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].
    We propose to authorize take by Level B harassment only for the 
proposed marine geophysical survey in the northwestern Pacific Ocean. 
Acoustic stimuli (i.e., increased underwater sound) generated during 
the operation of the seismic airgun array may have the potential to 
cause marine mammals in the survey area to be exposed to sounds at or 
greater than 160 dB re: 1 [mu]Pa or cause temporary, short-term changes 
in behavior. There is no evidence that the Observatory's planned 
activities could result in injury, serious injury or mortality within 
the specified geographic area for the requested authorization. The 
required mitigation and monitoring measures will minimize any potential 
risk for injury, serious injury, or mortality.
    The following sections describe the Observatory's methods to 
estimate take by incidental harassment and present their estimates of 
the numbers of marine mammals that could be affected during the 
proposed seismic program. The Observatory's estimates assume that 
marine mammals exposed to airgun sounds greater than or equal to 160 dB 
re: 1 [micro]Pa might change their behavior sufficiently for us to 
consider them as taken by harassment. They have based their estimates 
on the number of marine mammals that could be disturbed appreciably by 
operations with the 36-

[[Page 25986]]

airgun array during approximately 4,991 km (3,101.2 mi) of transect 
lines in the northeastern Pacific Ocean.
    We assume that during simultaneous operations of the airgun array 
and the other sources, any marine mammals close enough to be affected 
by the 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, we expect that the marine 
mammals would exhibit no more than short-term and inconsequential 
responses to the echosounder and profiler given their characteristics 
(e.g., narrow downward-directed beam) and other considerations 
described previously. Based on the best available information, we do 
not consider that these reactions constitute a ``take'' (NMFS, 2001). 
Therefore, the Observatory did not provide any additional allowance for 
animals that could be affected by sound sources other than the airguns.
    Ensonified Area Calculations--Because the Observatory assumes that 
the Langseth may need repeat some tracklines, accommodate the turning 
of the vessel, address equipment malfunctions, or conduct equipment 
testing to complete the survey; they have increased the proposed number 
of line-kilometers for the seismic operations by 25 percent (i.e., 
contingency lines).
    The Observatory calculated the expected ensonified area by entering 
the planned survey lines (including the 25 percent contingency lines) 
into a Map-Info Geographic Information System (system). The Observatory 
used the system to draw a 160-dB radius (see Table 2) around the 
operating airgun array (i.e., the ensonified area) around each seismic 
line. This first calculation is the area excluding overlap.
    Depending on the spacing of the transect lines within the 
ensonified area, the Observatory may also calculate areas of transit 
overlap. For example, if the ratio of transit overlap is 1.5 times the 
area excluding overlap, then the marine mammal that stayed within area 
during the entire survey could be exposed to acoustic stimuli 
approximately two times. However, it is unlikely that a particular 
animal would stay in the area during the entire survey. For the Juan de 
Fuca Survey, the transit lines are closely spaced together and the 
ratio of transect overlap is 1.7 greater than the area excluding 
overlapping transect lines. For the Cascadia Thrust Zone Survey the 
ratio is 2.8, and for the Cascadia Subduction Margin Survey the ratio 
is 2.0 times the area excluding overlap. Table 4 presents the area 
calculations for each survey. Refer to the authorization application 
and Assessment for additional information.

 Table 4--Ensonified Area Calculations for Three Proposed Seismic Surveys in the Northeast Pacific Ocean, During
                                                 June-July 2012
----------------------------------------------------------------------------------------------------------------
                                                 Area      Area with
                                              excluding   contingency                                   Overlap
                   Survey                      overlap       lines          Transect line spacing        ratio
                                               (km\2\)      (km\2\)                                     (km\2\)
----------------------------------------------------------------------------------------------------------------
Juan de Fuca Plate.........................       18,471       23,089  Closely spaced................        1.7
Cascadia Thrust Zone.......................       11,448       14,310  Closely spaced................        2.8
Cascadia Subduction Margin.................       11,387       14,234  Closely spaced................        2.0
----------------------------------------------------------------------------------------------------------------

    Density Information--The Observatory calculated the density data 
for 26 species reported off the Oregon and Washington coasts in the 
northeastern Pacific Ocean using the following data sources:
     Pooled results of the 1991-2008 NMFS Southwest Fishery 
Science Center ship surveys as synthesized by Barlow and Forney (2007) 
and Barlow (2010) for all species except the gray whale and harbor 
porpoise.
     Abundance estimates for gray whales that remain between 
Oregon and B.C. in summer and the within area out to 43 km (26.7 mi) 
from shore in the U.S. Navy's Keyport Range Complex Extension 
Environmental Impact Statement/Overseas Environmental Impact Statement 
(DoN, 2010); and
     The population estimate for the Northern Oregon/Washington 
Coast stock of harbor porpoises from the Pacific Marine Mammal Stock 
Assessments 2010 Report (Carretta et al., 2010).
    For the pooled results of the 1991-2008 NMFS Southwest Fishery 
Science Center ship surveys, the Observatory has corrected the 
densities for trackline detectability probability bias and availability 
bias. Trackline detectability probability bias is associated with 
diminishing sightability with increasing lateral distance from the 
track line [f (0)]. Availability bias refers to the fact that there is 
less than a 100 percent probability of sighting an animal that is 
present along the survey track line, and it is measured by g (0).
    Exposure Calculations--The Observatory calculated the number of 
different individuals that could be exposed to airgun sounds with 
received levels greater than or equal to 160 dB re: 1 [micro]Pa by 
multiplying the expected density of the marine mammals by the 
ensonified area excluding areas of overlap. This area includes the 25 
percent contingency lines.
    Any marine mammal sightings within or near the designated exclusion 
zone will result in the shutdown of seismic operations as a mitigation 
measure. Thus, the following estimates of the numbers of marine mammals 
potentially exposed to 160 dB re: 1 [micro]Pa sounds are precautionary, 
and probably overestimate the actual numbers of marine mammals that 
might be involved. These estimates assume that there will be no 
weather, equipment, or mitigation delays, which is highly unlikely.
    Because this approach does not allow for turnover in the mammal 
populations in the study area during the course of the survey, the 
actual number of individuals exposed could be underestimated. However, 
the approach assumes that no cetaceans will move away from or toward 
the trackline as the Langseth approaches in response to increasing 
sound levels prior to the time the levels reach 160 dB re: 1 [micro]Pa, 
which will result in overestimates for those species known to avoid 
seismic vessels.

Juan de Fuca Plate Survey Exposure Estimates

    The total 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 during this survey is 10,208 (see Table 5). The 
total includes 78 baleen whales, 56 of which are endangered: four blue 
whales (0.17 percent of the regional population), 30 fin whales (0.18 
percent of the regional population), 19 humpback whales (0.09 percent 
of the regional population), and four sei whales (0.03 percent of the

[[Page 25987]]

population). In addition, 24 sperm whales (0.10 percent of the regional 
population) and 303 Steller sea lions (0.46 percent of the population) 
(both listed as endangered under the Endangered Species Act) could be 
exposed during the survey.
    Of the cetaceans potentially exposed, 57 percent are delphinids and 
42 percent are pinnipeds. The most common species in the area 
potentially exposed to sound levels greater than or equal to 160 dB re: 
1 [mu]Pa during the proposed survey would be harbor porpoises (2,153 or 
4.12 percent), Dall's porpoises (1,935 or 4.61 percent), northern fur 
seals (1,931 or 0.30 percent), and northern elephant seals (1,058 or 
0.85 percent).

  Table 5--Estimates of the Possible Numbers of Marine Mammals Exposed to Sound Levels Greater Than or Equal to
 160 dB re: 1 [mu]Pa During the Proposed Juan de Fuca Plate Seismic Survey in the Northeast Pacific Ocean, June-
                                                    July 2012
----------------------------------------------------------------------------------------------------------------
                                                                     Estimated
                                                                     number of
                                                                    individuals                     Approximate
                                                                    exposed to     Requested or     percent of
                             Species                               sound levels    adjusted take     regional
                                                                   >=160 dB re:    authorization  population \2\
                                                                    1 [micro]Pa
                                                                        \1\
----------------------------------------------------------------------------------------------------------------
Gray whale......................................................              10              10               0
Humpback whale..................................................              19              19            0.09
Minke whale.....................................................              11              11            0.12
Sei whale.......................................................               4               4            0.03
Fin whale.......................................................              30              30            0.18
Blue whale......................................................               4               4            0.17
 
                           Odontocetes
 
Sperm whale.....................................................              24              24            0.10
Pygmy/Dwarf sperm whale.........................................              16              16             N/A
Cuvier's beaked whale...........................................              10              10            0.46
Baird's beaked whale............................................              27              27             3.0
Mesoplodon spp.\3\..............................................              40              40            3.95
Striped dolphin.................................................               1           \4\ 2            0.01
Short-beaked common dolphin.....................................             237         \4\ 238            0.06
Pacific white-sided dolphin.....................................             806             806             299
Northern right whale dolphin....................................             297             297            3.57
Risso's dolphin.................................................             258             258            4.12
Killer whale....................................................              38              38            1.55
Harbor porpoise \5\.............................................           2,153           2,153            4.12
Dall's porpoise.................................................           1,935           1,935            4.61
 
                            Pinnipeds
 
Northern fur seal...............................................           1,931           1,931            0.30
Steller sea lion................................................             303             303            0.46
Harbor seal \5\.................................................             995             995            4.02
Northern elephant seal..........................................           1,058           1,058            0.85
----------------------------------------------------------------------------------------------------------------
N/A = Not Available
\1\ Estimates are based on densities in Table 3 and an ensonified area (including 25% contingency of 23,089
  km\2\).
\2\ Regional population size estimates are from Table 3 (page 48 in Application 1).
\3\ Includes Blainville's, Stejneger's, and Hubb's beaked whales.
\4\ Requested take authorization increased to mean group size (see Application 1).
\5\ Estimates based on densities from Table 3 (page 48 in Application 1) and an ensonified area in
  water depths less than 100 m (328 ft) (including 25 percent contingency) of 3,404 km.\2\

Cascadia Thrust Zone Survey Exposure Estimates

    The total 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 during this survey is 15,100 (see Table 6). The 
total includes 79 baleen whales, 35 of which are endangered: Three blue 
whales (0.10 percent of the regional population), 18 fin whales (0.11 
percent of the regional population), 12 humpback whales (0.06 percent 
of the regional population), and two sei whales (0.02 percent of the 
population). In addition, 15 sperm whales (0.06 percent of the regional 
population) and 188 Steller sea lions (0.29 percent of the population) 
(both listed as endangered under the Endangered Species Act) could be 
exposed during the survey.
    Of the cetaceans potentially exposed, 63 percent are delphinids and 
36 percent are pinnipeds. The most common species in the area 
potentially exposed to sound levels greater than or equal to 160 dB re: 
1 [micro]Pa during the proposed survey would be Dall's porpoises (1,199 
or 2.86 percent), harbor porpoises (7,314 or 14 percent of the regional 
population or 9.2 percent of the overall population), and harbor seals 
(3,380 or 13.67 percent of the regional population or 4.6% of the 
overall population) and northern fur seals (1,197 or 0.18 percent) 
(Allen and Angliss, 2011). The percentages for harbor porpoises and 
harbor seals are the upper boundaries of the regional populations that 
could be affected by the proposed survey. However, these take estimates 
are small relative to the overall population sizes for each species in 
the northeast Pacific. Thus, these take estimates are likely an 
overestimate of the actual number of animals that may be taken by Level 
B harassment and we expect that the actual number of individual animals 
that may be taken by Level B harassment to be less than the request.

[[Page 25988]]



  Table 6--Estimates of the Possible Numbers of Marine Mammals Exposed to Sound Levels Greater Than or Equal to
160 dB re: 1 [mu]Pa During the Proposed Cascadia Thrust Zone Seismic Survey in the Northeast Pacific Ocean, July
                                                      2012
----------------------------------------------------------------------------------------------------------------
                                                                     Estimated
                                                                     number of
                                                                    individuals    Requested or     Approximate
                             Species                                exposed to     adjusted take    percent of
                                                                   sound levels    authorization     regional
                                                                  >=160 dB re: 1                  population \2\
                                                                    [mu]Pa \1\
----------------------------------------------------------------------------------------------------------------
Gray whale......................................................              35              35            0.18
Humpback whale..................................................              12              12            0.06
Minke whale.....................................................               7               7            0.07
Sei whale.......................................................               2               2            0.02
Fin whale.......................................................              18              18            0.11
Blue whale......................................................               3               3            0.10
 
                           Odontocetes
 
Sperm whale.....................................................              15              15            0.06
Pygmy/Dwarf sperm whale.........................................              10              10              NA
Cuvier's beaked whale...........................................               6               6            0.28
Baird's beaked whale............................................              17              17            1.86
Mesoplodon spp.\3\..............................................              25              25            2.45
Striped dolphin.................................................               1           \4\ 2           <0.01
Short-beaked common dolphin.....................................             147         \4\ 238            0.04
Pacific white-sided dolphin.....................................             500             500            1.86
Northern right whale dolphin....................................             184             184            2.21
Risso's dolphin.................................................             160             160            2.55
Killer whale....................................................              24              24            0.96
Harbor porpoise \5\.............................................           7,314           7,314           14.00
Dall's porpoise.................................................           1,199           1,199            2.86
 
                            Pinnipeds
 
Northern fur seal...............................................           1,197           1,197            0.18
Steller sea lion................................................             188             188            0.29
Harbor seal \5\.................................................           3,380           3,380           13.67
Northern elephant seal..........................................             656             656            0.53
----------------------------------------------------------------------------------------------------------------
N/A = Not Available.
\1\ Estimates are based on densities in Table 3 and an ensonified area (including 25% contingency of 14,310
  km\2\).
\2\ Regional population size estimates are from Table 3 (page 47 in Application 2).
\3\ Includes Blainville's, Stejneger's, and Hubb's beaked whales.
\4\ Requested take authorization increased to mean group size (see Application 2).
\5\ Estimates based on densities from Table 3 (page 47 in Application 2) and an ensonified area in
  water depths less than 100 m (328 ft) (including 25 percent contingency) of 11.565 km\2\.

Cascadia Subduction Margin Survey Exposure Estimates

    The total 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 during this survey is 8,132 (see Table 7). The 
total includes 54 baleen whales, 35 of which are endangered: three blue 
whales (0.10 percent of the regional population), 18 fin whales (0.11 
percent of the regional population), 11 humpback whales (0.06 percent 
of the regional population), and two sei whales (0.02 percent of the 
population). In addition, 15 sperm whales (0.06 percent of the regional 
population) and 187 Steller sea lions (0.29 percent of the population) 
(both listed as endangered under the Endangered Species Act) could be 
exposed during the survey.
    Of the cetaceans potentially exposed, 59 percent are delphinids and 
40 percent are pinnipeds. The most common species in the area 
potentially exposed to sound levels greater than or equal to 160 dB re: 
1 [mu]Pa during the proposed survey would be harbor porpoises (2,580 or 
4.94 percent), Dall's porpoises (1,193 or 2.84 percent), northern fur 
seals (1,190 or 0.18 percent), and harbor seals (1,192 or 4.82 
percent).

  Table 7--Estimates of the Possible Numbers of Marine Mammals Exposed to Sound Levels Greater Than or Equal to
   160 dB re: 1 [mu]Pa During the Proposed Cascadia Subduction Margin Seismic Survey in the Northeast Pacific
                                                Ocean, July 2012
----------------------------------------------------------------------------------------------------------------
                                                                     Estimated
                                                                     number of
                                                                    individuals    Requested or     Approximate
                             Species                                exposed to     adjusted take    percent of
                                                                   sound levels    authorization     regional
                                                                   >=160 dB  re:                  population \2\
                                                                    1 [mu]Pa\1\
----------------------------------------------------------------------------------------------------------------
Gray whale......................................................              12              12            0.06
Humpback whale..................................................              11              11            0.06

[[Page 25989]]

 
Minke whale.....................................................               6               6            0.07
Sei whale.......................................................               2               2            0.02
Fin whale.......................................................              18              18            0.11
Blue whale......................................................               3               3            0.10
 
                           Odontocetes
 
Sperm whale.....................................................              15              15            0.06
Pygmy/Dwarf sperm whale.........................................              10              10              NA
Cuvier's beaked whale...........................................               6               6            0.28
Baird's beaked whale............................................              17              17            1.85
Mesoplodon spp.\3\..............................................              25              25            2.44
Striped dolphin.................................................               1           \4\ 2           <0.01
Short-beaked common dolphin.....................................             146         \4\ 238            0.04
Pacific white-sided dolphin.....................................             497             497            1.85
Northern right whale dolphin....................................             183             183            2.20
Risso's dolphin.................................................             159             159            2.54
Killer whale....................................................              24              24            0.96
Harbor porpoise \5\.............................................           2,580           2,580            4.94
Dall's porpoise.................................................           1,193           1,193            2.84
 
                            Pinnipeds
 
Northern fur seal...............................................           1,190           1,190            0.18
Steller sea lion................................................             187             187            0.29
Harbor seal \5\.................................................           1,192           1,192            4.82
Northern elephant seal..........................................             652             652            0.53
----------------------------------------------------------------------------------------------------------------
N/A = Not Available.
\1\ Estimates are based on densities in Table 3 and an ensonified area (including 25% contingency of 14,234
  km\2\).
\2\ Regional population size estimates are from Table 3 (page 47 in Application 3).
\3\ Includes Blainville's, Stejneger's, and Hubb's beaked whales.
\4\ Requested take authorization increased to mean group size (see Application 3).
\5\ Estimates based on densities from Table 3 (page 47 in Application 3) and an ensonified area in
  water depths less than 100 m (328 ft) (including 25 percent contingency) of 4,080 km\2\.

Encouraging and Coordinating Research

    The Observatory and the Foundation will coordinate the planned 
marine mammal monitoring program associated with each seismic survey in 
the northwestern Pacific Ocean with other parties that may have 
interest in the area and/or may be conducting marine mammal studies in 
the same region during the seismic surveys.
    Negligible Impact and Small Numbers Analysis and Determination
    We have 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, 
we consider:
    (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.
    For reasons stated previously in this document, the specified 
activities associated with the marine seismic surveys are not likely to 
cause permanent threshold shift, or other non-auditory injury, serious 
injury, or death because:
    (1) The likelihood that, given sufficient notice through relatively 
slow ship speed, we expect marine mammals 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 that we would likely avoid this impact through the 
incorporation of the required monitoring and mitigation measures 
(described previously in this document);
    (3) The fact that cetaceans would have to be closer than 940 m 
(3,084 ft) in deep water, 1,540 m (5,052 ft) in intermediate depths, 
and 2,140 m (7,020 ft) in shallow depths, when the 36-airgun array is 
in use at 9 m (29.5 ft) tow depth from the vessel to be exposed to 
levels of sound believed to have a minimal chance of causing permanent 
threshold shift;
    (4) The fact that cetaceans would have to be closer than 1,100 m 
(3,609 ft) in deep water, 1,810 m (5,938 ft) in intermediate depths, 
and 2,520 m (8,268 ft) in shallow depths, when the 36-airgun array is 
in use at 12 m (39.4 ft) tow depth from the vessel to be exposed to 
levels of sound believed to have a

[[Page 25990]]

minimal chance of causing permanent threshold shift;
    (5) The fact that cetaceans would have to be closer than 1,200 m 
(3,937 ft) in deep water, 1,975 m (6,480 ft) in intermediate depths, 
and 2,750 m (9,022 ft) in shallow depths, when the 36-airgun array is 
in use at 15 m (49.2 ft) tow depth from the vessel to be exposed to 
levels of sound believed to have a minimal chance of causing permanent 
threshold shift;
    (6) The fact that cetaceans would have to be closer than 40 m (131 
ft) in deep water, 60 m (197 ft) in intermediate depths, and 296 m (971 
ft) in shallow depths, when the single airgun is in use at six to 15 m 
(20 to 49.2 ft) tow depth from the vessel to be exposed to levels of 
sound believed to have a minimal chance of causing permanent threshold 
shift;
    (7) The fact that pinnipeds would have to be closer than 400 m 
(1,312 ft) in deep water, 550 m (1,804 ft) in intermediate depths, and 
680 m (2,231 ft) in shallow depths, when the 36-airgun array is in use 
at 9 m (29.5 ft) tow depth from the vessel to be exposed to levels of 
sound believed to have a minimal chance of causing permanent threshold 
shift;
    (8) The fact that pinnipeds would have to be closer than 460 m 
(1,509 ft) in deep water, 615 m (2,018 ft) in intermediate depths, and 
770 m (2,526 ft) in shallow depths, when the single airgun is in use at 
12 m (39.4 ft) tow depth from the vessel to be exposed to levels of 
sound believed to have a minimal chance of causing permanent threshold 
shift;
    (9) The fact that pinnipeds would have to be closer than 520 m 
(1,706 ft) in deep water, 690 m (2,264 ft) in intermediate depths, and 
865 m (2,838 ft) in shallow depths, when the single airgun is in use at 
15 m (49.2 ft) tow depth from the vessel to be exposed to levels of 
sound believed to have a minimal chance of causing permanent threshold 
shift;
    (10) The fact that pinnipeds would have to be closer than 12 m 
(39.4 ft) in deep water, 18 m (59 ft) in intermediate depths, and 150 m 
(492 ft) in shallow depths, when the single airgun is in use at six to 
15 m (20 to 49.2 ft) tow depth from the vessel to be exposed to levels 
of sound believed to have a minimal chance of causing permanent 
threshold shift; and
    (11) The likelihood that marine mammal detection ability by trained 
visual observers is high at close proximity to the vessel.
    We do not anticipate that any injuries, serious injuries, or 
mortalities would occur as a result of the Observatory's planned marine 
seismic surveys, and we do not propose to authorize injury, serious 
injury or mortality for this survey. We anticipate only short-term 
behavioral disturbance to occur during the conduct of the survey 
activities. Tables 5, 6, and 7 of this document outline the number of 
requested Level B harassment takes that we anticipate 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 in this notice), we do not expect 
the activity to impact rates of recruitment or survival for any 
affected species or stock. Further, the seismic surveys would not take 
place in areas of significance for marine mammal feeding, resting, 
breeding, or calving and would not adversely impact marine mammal 
habitat.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (i.e., 24 hour cycle). 
Behavioral reactions to noise exposure (such as disruption of critical 
life functions, displacement, or avoidance of important habitat) are 
more likely to be significant if they last more than one diel cycle or 
recur on subsequent days (Southall et al., 2007). While we anticipate 
that the seismic operations would occur on consecutive days, the 
estimated duration of the Juan de Fuca Plate survey would last no more 
than 17 days, the Cascadia Thrust Zone survey would last approximately 
three days, and the Cascadia Subduction Margin survey would occur over 
10 days.
    Because the Langseth will move continuously along planned 
tracklines, each seismic survey would increase sound levels in the 
marine environment surrounding the vessel for 21 days during the first 
and second study and for 10 days during the last study. There will be 
an estimated 4-day period of non-seismic activity between the second 
and third survey.
    Of the 31 marine mammal species under our jurisdiction that are 
known to occur or likely to occur in the study area, six of these 
species and two stocks are listed as endangered under the Endangered 
Species Act: The blue, fin, humpback, north Pacific right, sei, and 
sperm whales; the southern resident stock of killer whales; and the 
eastern U.S. stock of the Steller sea lion. These species are also 
categorized as depleted under the Marine Mammal Protection Act. With 
the exception of North Pacific right whales, the Observatory has 
requested authorized take for these listed species. To protect these 
animals (and other marine mammals in the study area), the Observatory 
must cease or reduce airgun operations if animals enter designated 
zones.
    Based on available data, we do not expect the Observatory to 
encounter five of the 31 species under our jurisdiction in the proposed 
survey areas. They include the following: The north Pacific right, 
false killer, and short-finned pilot whales; the California sea lion; 
and the bottlenose dolphin because of the species' rare and/or 
extralimital occurrence in the survey areas. As mentioned previously, 
we estimate that 26 species of marine mammals under our jurisdiction 
could be potentially affected by Level B harassment over the course of 
the proposed authorization. For each species, these numbers are small, 
relative to the regional or overall population size and we have 
provided the regional population estimates for the marine mammal 
species that may be taken by Level B harassment in Tables 5, 6, and 7 
in this document. Our practice has been to apply the 160 dB re: 1 
[micro]Pa received level threshold for underwater impulse sound levels 
to determine whether take by Level B harassment occurs. Southall et al. 
(2007) provides 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]).
    We have preliminarily determined, provided that the aforementioned 
mitigation and monitoring measures are implemented, that the impact of 
conducting three marine seismic surveys off Oregon and Washington in 
the northwestern Pacific Ocean, June through July, 2012, 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 Tables 5, 6, and 7 for the requested 
authorized take numbers of cetaceans.
    While these species may make behavioral modifications, including 
temporarily vacating the area during the operation of the airgun(s) to 
avoid the resultant acoustic disturbance, the availability of alternate 
areas within these areas and the short duration of the research 
activities, have led us to preliminarily determine that this action 
will have a negligible impact on the species in the specified 
geographic region.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the mitigation and monitoring 
measures, we preliminarily find that the Observatory's

[[Page 25991]]

planned research activities will result in the incidental take of small 
numbers of marine mammals, by Level B harassment only, and that the 
required measures mitigate impacts to affected species or stocks of 
marine mammals to the lowest level practicable.

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

    Section 101(a)(5)(D) of the Marine Mammal Protection Act also 
requires us to determine that the authorization will not have an 
unmitigable adverse effect on the availability of marine mammal species 
or stocks for subsistence use. There are no relevant subsistence uses 
of marine mammals in the study area (northeastern Pacific Ocean) that 
implicate section 101(a)(5)(D) of the Marine Mammal Protection Act.

Endangered Species Act

    Of the species of marine mammals that may occur in the proposed 
survey area, several are listed as endangered under the Endangered 
Species Act, including the blue, fin, humpback, north Pacific right, 
sei, and sperm whales. The Observatory did not request take of 
endangered north Pacific right whales because of the low likelihood of 
encountering these species during the cruise.
    Under section 7 of the Act, the Foundation has initiated formal 
consultation with the Service's, Office of Protected Resources, 
Endangered Species Act Interagency Cooperation Division, on this 
proposed seismic survey. We (i.e., National Marine Fisheries Service, 
Office of Protected Resources, Permits and Conservation Division), have 
also initiated formal consultation under section 7 of the Act with the 
Endangered Species Act Interagency Cooperation Division to obtain a 
Biological Opinion (Opinion) evaluating the effects of issuing an 
incidental harassment authorization for threatened and endangered 
marine mammals and, if appropriate, authorizing incidental take. We 
will conclude the formal section 7 consultation prior to making a 
determination on whether or not to issue the authorization. If we issue 
the take authorization, the Foundation and the Observatory must comply 
with the Terms and Conditions of the Opinion's Incidental Take 
Statement in addition to the mitigation and monitoring requirements 
included in the issued take authorization.

National Environmental Policy Act (NEPA)

    With its complete application, the Foundation and the Observatory 
provided an ``Environmental Assessment and Finding of No Significant 
Impact Determination Pursuant to the National Environmental Policy Act, 
(NEPA: 42 U.S.C. 4321 et seq.) and Executive Order 12114 for a ``Marine 
Seismic Survey in the northeastern Pacific Ocean, 2012,'' which 
incorporates an ``Environmental Assessment of a Marine Geophysical 
Survey by the R/V Marcus G. Langseth in the northeastern Pacific Ocean, 
June-July 2012,'' prepared by LGL Limited environmental research 
associates.
    The Assessment analyzes the direct, indirect, and cumulative 
environmental impacts of the specified activities on marine mammals 
including those listed as threatened or endangered under the Endangered 
Species Act. We have conducted an independent review and evaluation of 
the document for sufficiency and compliance with the Council of 
Environmental Quality and NOAA Administrative Order 216-6 Sec.  
5.09(d), Environmental Review Procedures for Implementing the National 
Environmental Policy Act, and have preliminarily determined that 
issuance of the incidental harassment authorization is not likely to 
result in significant impacts on the human environment. Consequently, 
we plan to adopt the Foundation's Assessment and intend to prepare a 
Finding of No Significant Impact for the issuance of the authorization.

Proposed Authorization

    As a result of these preliminary determinations, we propose to 
authorize the take of marine mammals incidental to the Observatory's 
proposed marine seismic surveys in the northeast Pacific Ocean, 
provided the previously mentioned mitigation, monitoring, and reporting 
requirements are incorporated. The duration of the incidental 
harassment authorization would not exceed one year from the date of its 
issuance.

Information Solicited

    We request interested persons to submit comments and information 
concerning this proposed project and our preliminary determination of 
issuing a take authorization (see ADDRESSES). Concurrent with the 
publication of this notice in the Federal Register, we will forward 
copies of this application to the Marine Mammal Commission and its 
Committee of Scientific Advisors.

    Dated: April 27, 2012.
Helen M. Golde,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2012-10627 Filed 5-1-12; 8:45 am]
BILLING CODE 3510-22-P