`[Federal Register Volume 80, Number 54 (Friday, March 20, 2015)]
[Notices]
[Pages 15060-15097]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-06261]



[[Page 15059]]

Vol. 80

Friday,

No. 54

March 20, 2015

Part II





Department of Commerce





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





National Oceanic and Atmospheric Administration





Takes of Marine Mammals Incidental to Specified Activities; Low-Energy 
Marine Geophysical Survey in the Southwest Pacific Ocean, East of New 
Zealand, May to June 2015; Notice

  Federal Register / Vol. 80 , No. 54 / Friday, March 20, 2015 / 
Notices  

[[Page 15060]]


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

DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XD727


Takes of Marine Mammals Incidental to Specified Activities; Low-
Energy Marine Geophysical Survey in the Southwest Pacific Ocean, East 
of New Zealand, May to June 2015

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

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

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

SUMMARY: NMFS has received an application from the Scripps Institution 
of Oceanography (SIO), on behalf of SIO and the U.S. National Science 
Foundation (NSF), for an Incidental Harassment Authorization (IHA) to 
take marine mammals, by harassment, incidental to conducting a low-
energy marine geophysical (seismic) survey in the Southwest Pacific 
Ocean, East of New Zealand, May to June 2015. Pursuant to the Marine 
Mammal Protection Act (MMPA), NMFS is requesting comments on its 
proposal to issue an IHA to SIO to incidentally harass, by Level B 
harassment only, 32 species of marine mammals during the specified 
activity.

DATES: Comments and information must be received no later than April 
20, 2015.

ADDRESSES: Comments on the application should be addressed to Jolie 
Harrison, Chief, Permits and Conservation Division, Office of Protected 
Resources, National Marine Fisheries Service, 1315 East-West Highway, 
Silver Spring, MD 20910. The mailbox address for providing email 
comments is [email protected]. Please include 0648-XD727 in the 
subject line. NMFS is not responsible for email comments sent to 
addresses other than the one provided here. Comments sent via email, 
including all attachments, must not exceed a 25-megabyte file size.
    Instructions: All comments received are a part of the public record 
and will generally be posted to: http://www.nmfs.noaa.gov/pr/permits/incidental/ without change. All Personal Identifying Information (for 
example, name, address, etc.) voluntarily submitted by the commenter 
may be publicly accessible. Do not submit Confidential Business 
Information or otherwise sensitive or protected information.
    A copy of the IHA application may be obtained by writing to the 
address specified above, telephoning the contact listed here (see FOR 
FURTHER INFORMATION CONTACT) or visiting the Internet at: http://www.nmfs.noaa.gov/pr/permits/incidental/. Documents cited in this 
notice may also be viewed by appointment, during regular business 
hours, at the aforementioned address.
    A ``Draft Environmental Analysis of a Low-Energy Marine Geophysical 
Survey by the R/V Roger Revelle in the Southwest Pacific Ocean, East of 
New Zealand, May to June 2015'' (Draft Environmental Analysis) in 
accordance with the National Environmental Policy Act (NEPA) and the 
regulations published by the Council of Environmental Quality (CEQ), 
has been prepared on behalf of NSF and SIO. It is posted at the 
foregoing site. NMFS has independently evaluated the Draft 
Environmental Analysis and has prepared a separate NEPA analysis titled 
``Draft Environmental Assessment on the Issuance of an Incidental 
Harassment Authorization to the Scripps Institution of Oceanography to 
Take Marine Mammals by Harassment Incidental to a Low-Energy Marine 
Geophysical Survey in the Southwest Pacific Ocean, East of New Zealand, 
May to June 2015.'' Information in the SIO's IHA application, Draft 
Environmental Analysis, Draft EA and this notice of the proposed IHA 
collectively provide the environmental information related to proposed 
issuance of the IHA for public review and comment. NMFS will review all 
comments submitted in response to this notice as we complete the NEPA 
process, including a decision of whether to sign a Finding of No 
Significant Impact (FONSI), prior to a final decision on the IHA 
request.

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

SUPPLEMENTARY INFORMATION: 

Background

    Sections 101(a)(5)(A) and (D) of the MMPA, (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce (Secretary) to allow, upon request, 
the incidental, but not intentional, taking of small numbers of marine 
mammals by United States citizens who engage in a specified activity 
(other than commercial fishing) within a specified geographical region 
if certain findings are made and either regulations are issued or, if 
the taking is limited to harassment, a notice of a proposed 
authorization is provided to the public for review.
    An authorization for incidental takings shall be granted if NMFS 
finds that the taking will have a negligible impact on the species or 
stock(s), will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for subsistence uses (where 
relevant), and if the permissible methods of taking and requirements 
pertaining to the mitigation, monitoring and reporting of such takings 
are set forth. NMFS has defined ``negligible impact'' in 50 CFR 216.103 
as ``. . . an impact resulting from the specified activity that cannot 
be reasonably expected to, and is not reasonably likely to, adversely 
affect the species or stock through effects on annual rates of 
recruitment or survival.''
    Section 101(a)(5)(D) of the MMPA established an expedited process 
by which citizens of the United States can apply for an authorization 
to incidentally take small numbers of marine mammals by harassment. 
Section 101(a)(5)(D) of the MMPA establishes a 45-day time limit for 
NMFS's review of an application, followed by a 30-day public notice and 
comment period on any proposed authorizations for the incidental 
harassment of small numbers of marine mammals. Within 45 days of the 
close of the public comment period, NMFS must either issue or deny the 
authorization.
    Except with respect to certain activities not pertinent here, the 
MMPA defines ``harassment'' as: any act of pursuit, torment, or 
annoyance which (i) has the potential to injure a marine mammal or 
marine mammal stock in the wild [Level A harassment]; or (ii) has the 
potential to disturb a marine mammal or marine mammal stock in the wild 
by causing disruption of behavioral patterns, including, but not 
limited to, migration, breathing, nursing, breeding, feeding, or 
sheltering [Level B harassment].

Summary of Request

    On December 15, 2014, NMFS received an application from SIO, on 
behalf of SIO and NSF, requesting that NMFS issue an IHA for the take, 
by Level B harassment only, of small numbers of marine mammals 
incidental to conducting a low-energy marine seismic survey as well as 
heat-flow measurements in the Southwest Pacific Ocean, at three sites 
off the east coast of New Zealand, during May to June 2015. The 
sediment coring component of the proposed project, which was described 
in the IHA application and Draft Environmental Analysis, was not funded 
and no piston or gravity coring for seafloor samples would be

[[Page 15061]]

conducted during the low-energy seismic survey. The low-energy seismic 
survey would take place within the Exclusive Economic Zone (EEZ) and 
outside the territorial waters of New Zealand. On behalf of SIO, the 
U.S. Department of State is seeking authorization from New Zealand for 
clearance to work within the EEZ.
    The research would be conducted by Oregon State University and 
funded by the U.S. National Science Foundation (NSF). SIO plan to use 
one source vessel, the R/V Roger Revelle (Revelle), and a seismic 
airgun array and hydrophone streamer to collect seismic data in the 
Southwest Pacific Ocean, East of New Zealand. SIO plans to use 
conventional low-energy, seismic methodology to perform marine-based 
studies in the Southwest Pacific Ocean (see Figure 1 of the IHA 
application). The studies would involve a low-energy seismic survey and 
heat-flow measurements from the seafloor to meet a number of research 
goals. In addition to the proposed operations of the seismic airgun 
array and hydrophone streamer, SIO intends to operate two additional 
acoustical data acquisition systems--a multi-beam echosounder and sub-
bottom profiler continuously throughout the low-energy seismic survey.
    Acoustic stimuli (i.e., increased underwater sound) generated 
during the operation of the seismic airgun array have the potential to 
cause behavioral disturbance for marine mammals in the proposed study 
area. This is the principal means of marine mammal taking associated 
with these activities, and SIO have requested an authorization to take 
32 species of marine mammals by Level B harassment. Take is not 
expected to result from the use of the multi-beam echosounder and sub-
bottom profiler, as the brief exposure of marine mammals to one pulse, 
or small numbers of signals, to be generated by these instruments in 
this particular case is not likely to result in the harassment of 
marine mammals. Also, NMFS does not expect take to result from 
collision with the source vessel because it is a single vessel moving 
at a relatively slow, constant cruise speed of 5 knots ([kts]; 9.3 
kilometers per hour [km/hr]; 5.8 miles per hour [mph]) during seismic 
acquisition within the study area, for a relatively short period of 
time (approximately 27 operational days). It is likely that any marine 
mammal would be able to avoid the vessel.

Description of the Proposed Specified Activity

Overview

    SIO proposes to use one source vessel, the Revelle, a two GI airgun 
array and one hydrophone streamer to conduct the conventional seismic 
survey as part of the NSF-funded research project ``Collaborative 
Research: The Thermal Regime of the Hikurangi Subduction Zone and 
Shallow Slow Slip Events, New Zealand.'' In addition to the airguns, 
SIO intends to conduct a bathymetric survey and heat-flow measurements 
at three sites off the southwest coast of North Island and northeast 
coast of South Island, New Zealand from the Revelle during the proposed 
low-energy seismic survey.

Proposed Dates and Duration

    The Revelle is expected to depart from Auckland, New Zealand on 
approximately May 18, 2015 and arrive at Napier, New Zealand on 
approximately June 18, 2015. Airgun operations would take approximately 
135 hours in total, and the remainder of the time would be spent in 
transit and collecting heat-flow measurements and cores. The total 
distance the Revelle would travel in the region to conduct the proposed 
research activities (i.e., seismic survey, bathymetric survey, and 
transit to heat-flow measurement locations) represents approximately 
2,000 km (1,079.9 nmi). Some minor deviation from this schedule is 
possible, depending on logistics and weather (e.g., the cruise may 
depart earlier or be extended due to poor weather; or there could be 
additional days of airgun operations if collected data are deemed to be 
of substandard quality).

Proposed Specified Geographic Region

    The proposed project and survey sites are located off the southeast 
coast of North Island and northeast coast of the South Island, New 
Zealand in selected regions of the Southwest Pacific Ocean. The 
proposed survey sites are located between approximately 38.5 to 
42.5[deg] South and approximately 174 to 180[deg] East off the east 
coast of New Zealand, in the EEZ of New Zealand and outside of 
territorial waters (see Figure 1 of the IHA Application). Water depths 
in the study area are between approximately 200 to 3,000 m (656.2 to 
9,842.5 ft). The proposed low-energy seismic survey would be collected 
in a total of nine grids of intersecting lines of two sizes (see Figure 
1 of the IHA application) at exact locations to be determined in the 
field during May to June 2015. Figure 1 also illustrates the general 
bathymetry of the proposed study area. The proposed low-energy seismic 
survey would be within an area of approximately 1,154 km\2\ (336.5 
nmi\2\). This estimate is based on the maximum number of kilometers for 
the low-energy seismic survey (1,250 km) multiplied by the area 
ensonified around the planned tracklines (2 x 0.6 km in intermediate 
water depths and 2 x 0.4 km in deep water depths). The ensonified area 
is based on the predicted rms radii (m) based on modeling and empirical 
measurements (assuming 100% use of the two 45 in\3\ GI airguns in 100 
to 1,000 m or greater than 1,000 m water depths), which was calculated 
to be 600 m (1,968.5 ft) or 400 m (1,312.3 ft).
BILLING CODE 3510-22-P

[[Page 15062]]

[GRAPHIC] [TIFF OMITTED] TN20MR15.000

BILLING CODE 3510-22-C

Detailed Description of the Proposed Specified Activity

    In support of a research project put forward by Oregon State 
University (OSU) and to be funded by NSF, SIO proposes to conduct a 
low-energy seismic survey in the Southwest Pacific Ocean, East of New 
Zealand, from May to June 2015. In addition to the low-energy seismic 
survey, scientific research activities would include conducting a 
bathymetric profile survey of the seafloor using transducer-based 
instruments such as a multi-beam echosounder and sub-bottom profiler; 
and heat-flow measurements from the seafloor using various methods and 
equipment at three sites off the southeast coast of North Island and 
northeast coast of South Island, New Zealand. Water depths in the 
survey area are approximately 200 to 3,000 meters (m) (656.2 to 9,842.5 
feet [ft]).

[[Page 15063]]

The proposed low-energy seismic survey is scheduled to occur for a 
total of approximately 135 hours over the course of the entire cruise, 
which would be for approximately 27 operational days in May to June 
2015. The proposed low-energy seismic survey would be conducted during 
the day (from nautical twilight-dawn to nautical twilight-dusk) and 
night, and for up to approximately 72 hours of continuous operations at 
a time. The operation hours and survey length would include equipment 
testing, ramp-up, line changes, and repeat coverage. Some minor 
deviation from these dates would be possible, depending on logistics 
and weather. The Principal Investigators are Dr. R. N. Harris and Dr. 
A. Trehu of the OSU.
    The proposed surveys would allow the development of a process-based 
understanding of the thermal structure of the Hikurangi subduction 
zone, and the expansion of this understanding by using regional 
observations of gas hydrate-related bottom simulating reflections. To 
achieve the proposed project's goals, the Principal Investigators 
propose to collect low-energy, high-resolution multi-channel system 
profiles, heat-flow measurements, and sediment cores along transects 
seaward and landward of the Hikurangi deformation front. Heat-flow 
measurements would be made in well-characterized sites, increasing the 
number of publicly available heat-flow and thermal conductivity 
measurements from this continental margin by two orders of magnitude. 
Seismic survey data would be used to produce sediment structural maps 
and seismic velocities to achieve the project objectives. Data from 
sediment cores would detect and estimate the nature and sources of 
fluid flow through high permeability pathways in the overriding plate 
and along the subduction thrust; characterize the hydrocarbon and gas 
hydrate system to assist with estimates of heat flow from Bottom 
Simulating Reflectors (BSR)s, their role in slope stability, and fluid 
source; and elucidate the response of microbes involved in carbon 
cycling to changes in methane flux.
    The low-energy seismic survey would be collected in a total of 9 
grids of intersecting lines of two sizes (see Figure 1 of the IHA 
application) at exact locations to be determined in the field. The 
water depths would be very similar to those at the nominal survey 
locations shown in Figure 1 of the IHA application. The northern and 
middle sites off the North Island would be the primary study areas, and 
the southern site off the South Island would be a contingency area that 
would only be surveyed if time permits. SIO's calculations assume that 
7 grids at the primary areas and two grids at the southern site would 
be surveyed. The total trackline distance of the low-energy seismic 
survey would be approximately 1,250 km (including the two South Island 
contingency sites), almost all in water depths greater than 1,000 m.
    The procedures to be used for the survey would be similar to those 
used during previous low-energy seismic surveys by SIO and NSF and 
would use conventional seismic methodology. The proposed survey would 
involve one source vessel, the Revelle. SIO would deploy a two Sercel 
Generator Injector (GI) airgun array (each with a discharge volume of 
45 in\3\ [290.3 cm\3\], in one string, with a total volume of 90 in\3\ 
[580.6 cm\3\]) as an energy source, at a tow depth of up to 2 m (6.6 
ft) below the surface (more information on the airguns can be found in 
SIO's IHA application). The airguns in the array would be spaced 
approximately 8 m (26.2 ft) apart and 21 m (68.9 ft) astern of the 
vessel. The receiving system would consist of one 600 m (1,968.5 ft) 
long, 48-channel hydrophone streamer(s) towed behind the vessel. Data 
acquisition is planned along a series of predetermined lines, almost 
all (approximately 95%) of which would be in water depths greater than 
1,000 m. As the GI airguns are towed along the survey lines, the 
hydrophone streamer would receive the returning acoustic signals and 
transfer the data to the onboard processing system. The seismic surveys 
would be conducted while the heat-flow probe is being recharged. All 
planned seismic data acquisition activities would be conducted by 
technicians provided by SIO, with onboard assistance by the scientists 
who have proposed the study. The vessel would be self-contained, and 
the crew would live aboard the vessel for the entire cruise.
    The planned seismic survey (including equipment testing, start-up, 
line changes, repeat coverage of any areas, and equipment recovery) 
would consist of approximately 1,250 kilometers (km) (674.9 nautical 
miles [nmi]) of transect lines (including turns) in the study area in 
the Southwest Pacific Ocean (see Figures 1 of the IHA application). 
Approximately 95% of the low-energy seismic survey would occur in water 
depths greater than 1,000 m. In addition to the operation of the airgun 
array and heat-flow measurements, a multi-beam echosounder and a sub-
bottom profiler would also likely be operated from the Revelle 
continuously throughout the cruise. There would be additional airgun 
operations associated with equipment testing, ramp-up, and possible 
line changes or repeat coverage of any areas where initial data quality 
is sub-standard. In SIO's estimated take calculations, 25% has been 
added for those additional operations.

   Table 1--Proposed Low-Energy Seismic Survey Activities in the Southwest Pacific Ocean, East of New Zealand
----------------------------------------------------------------------------------------------------------------
                                                                      Time between
     Survey length (km)        Total duration      Airgun array       airgun shots        Streamer length (m)
                                  (hr) \1\         total volume        (distance)
----------------------------------------------------------------------------------------------------------------
1,250 (674.9 nmi)...........              ~135  2 x 45 = 90 in\3\  6 to 10 seconds    600 (1,968.5 ft)
                                                 (2 x 1474.8        (18.5 to 31 m or
                                                 cm\3\).            60.7 to 101.7
                                                                    ft).
----------------------------------------------------------------------------------------------------------------
\1\ Airgun operations are planned for no more than approximately 72 continuous hours at a time.

Vessel Specifications

    The Revelle, a research vessel owned by the U.S. Navy and operated 
by SIO of the University of California San Diego, would tow the two GI 
airgun array, as well as the hydrophone streamer. When the Revelle is 
towing the airgun array and the relatively short hydrophone streamer, 
the turning rate of the vessel while the gear is deployed is 
approximately 20 degrees per minute, which is much higher than the 
limit of 5 degrees per minute for a seismic vessel towing a streamer of 
more typical length (much greater than 1 km [0.5 nmi]). Thus, the 
maneuverability of the vessel would not be limited much during 
operations with the streamer.
    The U.S.-flagged vessel, built in 1996, has a length of 83 m (272.3 
ft); a beam of 16.0 m (52.5 ft); a maximum draft of 5.2 m (19.5 ft); 
and a gross tonnage of 3,180. The ship is powered by two 3,000

[[Page 15064]]

horsepower (hp) Propulsion General Electric motors) and a 1,180 hp 
azimuthing jet bowthruster. The GI airgun compressor onboard the vessel 
is manufactured by Price Air Compressors. The Revelle's operation speed 
during seismic acquisition is typically approximately 9.3 km/hr (5 kts) 
(varying between 7.4 to 11.1 km/hr [4 to 6 kts]). When not towing 
seismic survey gear, the Revelle typically cruises at 22.2 to 23.1 km/
hr (12 to 12.5 kts) and has a maximum speed of 27.8 km/hr (15 kts). The 
Revelle has an operating range of approximately 27,780 km (15,000 nmi) 
(the distance the vessel can travel without refueling), which is 
approximately 70 to 75 days. The vessel can accommodate 37 scientists 
and 22 crew members.
    The vessel also has two observation station locations from which 
Protected Species Observers (PSO) would watch for marine mammals before 
and during the proposed airgun operations on the Revelle. Observing 
stations would be at the 02 level, with a PSO's eye level approximately 
10.4 m (34 ft) above sea level--one forward on the 02 deck commanding a 
forward-centered, approximately 240[deg] view around the vessel, and 
one atop the aft hangar, with an aft-centered view that includes the 
radii around the airguns. The eyes on the bridge watch would be at a 
height of approximately 15 m (49 ft); PSOs would work on the enclosed 
bridge and adjoining aft steering station during any inclement weather. 
More details of the Revelle can be found in the IHA application and 
online at: https://scripps.ucsd.edu/ships/revelle.

Acoustic Source Specifications--Seismic Airguns

    The Revelle would deploy an airgun array, consisting of two 45 
in\3\ Sercel GI airguns as the primary energy source and a 600 m 
streamer(s) containing hydrophones. The airgun array would have a 
supply firing pressure of 1,750 pounds per square inch (psi). Seismic 
pulses for the GI airguns would be emitted at intervals of 
approximately 6 to 10 seconds. There would be a maximum of 
approximately 360 shots per hour. The number of shots per hour would 
vary based upon the vessel speed over ground during the low-energy 
seismic survey. During firing, a brief (approximately 20 millisecond) 
pulse sound would be emitted; the airguns would be silent during the 
intervening periods. The dominant frequency components would range from 
0 to 188 Hertz (Hz).
    The GI airguns would fire the compressed air volume in unison in 
``true GI'' mode. The GI airguns would be used in ``true GI'' mode, 
that is, the volume of the injector chamber (I) (105 in\3\ [1721 
cm\3\]) of each GI airgun is greater to that of its generator chamber 
(G) (45 in\3\ [737 cm\3\]) for each airgun. The generator chamber of 
each GI airgun (45 in\3\) would be the primary source and the one 
responsible for introducing the sound pulse into the ocean. The larger 
(105 in\3\) injector chamber injects air into the previously-generated 
bubble to maintain its shape, and would not introduce more sound into 
the water. The two GI airguns would be spaced approximately 8 m (26.2 
ft) apart, side-by-side, 21 m (68.9 ft) behind the Revelle, at a depth 
of up to 2 m during the low-energy seismic survey.
    The Nucleus modeling software used at Lamont-Doherty Earth 
Observatory of Columbia University (L-DEO) does not include GI airguns 
as part of its airgun library, however signatures and mitigation models 
have been obtained for two 45 in\3\ G airguns that are close 
approximations. For the two 45 in\3\ airgun array, the source output 
(downward) is 230.6 dB re 1 [mu]Pam 0-to-peak and 235.8 dB re 1 [mu]Pam 
for peak-to-peak. The dominant frequency range would be 0 to 188 Hz for 
a pair of GI airguns towed at 2 m depth.
    During the low-energy seismic survey, the vessel would attempt to 
maintain a constant cruise speed of approximately 5 knots. The airguns 
would operate continuously for no more than approximately 72 hours at a 
time based on operational constraints. The total duration of the airgun 
operations would not exceed 135 hours. The relatively short, 48-channel 
hydrophone streamer would provide operational flexibility to allow the 
low-energy seismic survey to proceed along the designated cruise 
tracklines. The design of the seismic equipment is to achieve high-
resolution images with the ability to correlate to the ultra-high 
frequency sub-bottom profiling data and provide cross-sectional views 
to pair with the seafloor bathymetry.

Metrics Used in This Document

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

Characteristics of the Airgun Pulses

    Airguns function by venting high-pressure air into the water, which 
creates an air bubble. The pressure signature of an individual airgun 
consists of a sharp rise and then fall in pressure, followed by several 
positive and negative pressure excursions caused by the oscillation of 
the resulting air bubble. The oscillation of the air bubble transmits 
sounds downward through the seafloor, and the amount of sound 
transmitted in the near horizontal directions is reduced. However, the 
airgun array also emits sounds that travel horizontally toward non-
target areas.
    The nominal downward-directed source levels of the airgun arrays 
used by SIO on the Revelle do not represent actual sound levels that 
can be measured at any location in the water. Rather, they represent 
the level that would be found 1 m (3.3 ft) from a hypothetical point 
source emitting the same total amount of sound as is emitted by the 
combined GI airguns. The actual received level at any location in the 
water near the GI airguns would not exceed the source level of the 
strongest individual source. In this case, that would be about 224.6 dB 
re 1 [micro]Pam peak or 229.8 dB re 1 [micro]Pam peak-to-peak for the 
two 45 in\3\ airgun array. However, the difference between rms and peak 
or peak-to-peak values for a given pulse depends on the frequency 
content and duration of the pulse, among other factors. Actual levels 
experienced by any organism more than 1 m from either GI airgun would 
be significantly lower.
    Accordingly, L-DEO has predicted and modeled the received sound 
levels in relation to distance and direction from the two GI airgun 
array. These are the nominal source levels applicable to downward 
propagation. A detailed description of L-DEO's modeling for this 
survey's marine seismic source arrays for protected species mitigation 
is provided in the ``Programmatic

[[Page 15065]]

Environmental Impact Statement/Overseas Environmental Impact Statement 
prepared for Marine Seismic Research that is funded by the National 
Science Foundation and conducted by the U.S. Geological Survey'' (NSF/
USGS PEIS, 2011). The NSF/USGS PEIS discusses the characteristics of 
the airgun pulses. NMFS refers the reviewers to that document for 
additional information.

Predicted Sound Levels for the Airguns

    To estimate takes and determine mitigation (i.e., buffer and 
exclusion) zones for the airgun array to be used, received sound levels 
have been modeled by L-DEO for a number of airgun configurations, 
including two 45 in\3\ G airguns, in relation to distance and direction 
from the airguns (see Figure 2 of the IHA application). The model does 
not allow for bottom interactions, and is most directly applicable to 
deep water. Because the model results are for G airguns, which have 
more energy than GI airguns of the same size, those distances 
overestimate (by approximately 10%) the distances for the two 45 in\3\ 
GI airguns. Although the distances are overestimated, no adjustments 
for this have been made to the radii distances in Table 2 (below). 
Based on the modeling, estimates of the maximum distances from the GI 
airguns where sound levels of 190, 180, and 160 dB re 1 [micro]Pa (rms) 
are predicted to be received in intermediate and deep water are shown 
in Table 2 (see Table 1 of the IHA application).
    Empirical data concerning the 190, 180, and 160 dB (rms) distances 
were acquired for various airgun arrays based on measurements during 
the acoustic verification studies conducted by L-DEO in the northern 
Gulf of Mexico (GOM) in 2003 (Tolstoy et al., 2004) and 2007 to 2008 
(Tolstoy et al., 2009; Diebold et al., 2010). Results of the 18 and 36 
airgun array are not relevant for the two GI airguns to be used in the 
proposed low-energy seismic survey because the airgun arrays are not 
the same size or volume. The empirical data for the 6, 10, 12, and 20 
airgun arrays indicate that, for deep water, the L-DEO model tends to 
overestimate the received sound levels at a given distance (Tolstoy et 
al., 2004). For the two G airgun array, measurements were obtained only 
in shallow water. When compared to measurements in acquired in deep 
water, mitigation radii provided by the L-DEO model for the proposed 
airgun operations were found to be conservative. The acoustic 
verification surveys also showed that distances to given received 
levels vary with water depth; these are larger in shallow water, while 
intermediate/slope environments show characteristics intermediate 
between those of shallow water and those of deep water environments, 
and documented the influence of a sloping seafloor. The only 
measurements obtained for intermediate depths during either survey were 
for the 36-airgun array in 2007 to 2008 (Diebold et al., 2010). 
Following results obtained at this site and earlier practice, a 
correction factor of 1.5, irrespective of distance to the airgun array, 
is used to derive intermediate-water radii from modeled deep-water 
radii.
    Measurements were not made for a two GI airgun array in 
intermediate and deep water; however, SIO proposes to use the buffer 
and exclusion zones predicted by L-DEO's model for the proposed GI 
airgun operations in intermediate and deep water, although they are 
likely conservative given the empirical results for the other arrays. 
Using the L-DEO model, Table 2 (below) shows the distances at which 
three rms sound levels are expected to be received from the two GI 
airguns. The 160 dB re 1 [mu]Pam (rms) isopleth is the threshold 
specified by NMFS for potential Level B (behavioral) harassment from 
impulsive noise for both cetaceans and pinnipeds. The 180 and 190 dB re 
1 [mu]Pam (rms) isopleths are the thresholds currently used to estimate 
potential Level A harassment as specified by NMFS (2000) and are 
applicable to cetaceans and pinnipeds, respectively. Table 2 summarizes 
the predicted distances at which sound levels (160, 180, and 190 dB 
[rms]) are expected to be received from the two airgun array (each 45 
in\3\) operating in intermediate water (100 to 1,000 m [328.1 to 3,280 
ft]) and deep water (>1,000 m) depths.

  Table 2--Predicted and Modeled (Two 45 in\3\ GI Airgun Array) Distances to Which Sound Levels >=160, 180, and
190 dB re 1 [mu]Pa (rms) Could Be Received in Intermediate and Deep Water During the Proposed Low-Energy Seismic
                  Survey in the Southwest Pacific Ocean, East of New Zealand, May to June 2015
----------------------------------------------------------------------------------------------------------------
                                                              Predicted RMS radii distances (m) for 2 GI airgun
                                Tow depth                                           array
   Source and total volume         (m)      Water depth (m) ----------------------------------------------------
                                                                  160 dB            180 dB            190 dB
----------------------------------------------------------------------------------------------------------------
Two 45 in\3\ GI Airguns (90              2  Intermediate     600 (1,968.5 ft)  100 (328.1 ft)    15 (49.2 ft)
 in\3\).                                     (100 to 1,000).                                      *100 would be
                                                                                                  used for
                                                                                                  pinnipeds as
                                                                                                  described in
                                                                                                  NSF/USGS PEIS*
Two 45 in\3\ GI Airguns (90              2  Deep (>1,000)..  400 (1,312.3 ft)  100 (328.1 m)     10 (32.8 ft)
 in\3\).                                                                                          *100 would be
                                                                                                  used for
                                                                                                  pinnipeds as
                                                                                                  described in
                                                                                                  NSF/USGS PEIS*
----------------------------------------------------------------------------------------------------------------

    Based on the NSF/USGS PEIS and Record of Decision, for situations 
which incidental take of marine mammals is anticipated, proposed 
exclusion zones of 100 m for cetaceans and pinnipeds for all low-energy 
acoustic sources in water depths greater than 100 m would be 
implemented.
    NMFS expects that acoustic stimuli resulting from the proposed 
operation of the two GI airgun array has the potential to harass marine 
mammals. NMFS does not expect that the movement of the Revelle, during 
the conduct of the low-energy seismic survey, has the potential to 
harass marine mammals because the relatively slow operation speed of 
the vessel (approximately 5 kts; 9.3 km/hr; 5.8 mph) during seismic 
data acquisition should allow marine mammals to avoid the vessel.

Bathymetric Survey

    Along with the low-energy airgun operations, two additional 
geophysical (detailed swath bathymetry) measurements focused on a 
specific study area within the Southwest Pacific Ocean would be made 
using hull-mounted sonar system instruments from the Revelle for 
operational and navigational purposes. The ocean floor would be mapped 
with the Kongsberg EM 122 multi-beam echosounder and a Knudsen Chirp 
3260 sub-bottom profiler. During bathymetric survey operations, when 
the vessel is not towing seismic equipment, its average speed would be 
approximately 10.1 kts (18.8 km/hr). In cases where higher resolution 
bathymetric data is sought, the average speed may be as low as 5 kts 
(9.3 km/hr). These sound sources would be operated continuously from 
the Revelle throughout the cruise. Operating

[[Page 15066]]

characteristics for the instruments to be used are described below.
    Multi-Beam Echosounder (Kongsberg EM 122)--The hull-mounted multi-
beam sonar would be operated continuously during the cruise to map the 
ocean floor. This instrument would operate at a frequency of 10.5 to 13 
(usually 12) kilohertz (kHz) and would be hull-mounted. The 
transmitting beamwidth would be 1 or 2[deg] fore to aft and 150[deg] 
athwartship (cross-track). The estimated maximum source energy level 
would be 242 dB re 1[mu]Pa (rms). Each `ping' of eight (in water 
greater than 1,000 m or four (in water less than 1,000 m) successive 
fan-shaped transmissions, each ensonifying a sector that extends 1[deg] 
fore to aft. Continuous-wave signals increase from 2 to 15 milliseconds 
(ms) in water depths up to 2,600 m (8,530 ft), and FM chirp signals up 
to 100 ms long would be used in water greater than 2,600 m. The 
successive transmission span an overall cross-track angular extent of 
about 150[deg], with 2 ms gaps between the pings for successive 
sectors.
    Sub-Bottom Profiler--The Revelle would operate a Knudsen 3260 sub-
bottom profiler continuously throughout the cruise simultaneously to 
map and provide information about the seafloor sedimentary features and 
bottom topography that is mapped simultaneously with the multi-beam 
echosounder. The beam of the sub-bottom profiler would be transmitted 
as a 27[deg] cone, directed downward by a 3.5 kHz transducer in the 
hull of the Revelle. The nominal power output would be 10 kilowatt 
(kW), but the actual maximum radiated power would be 3 kW or 222 dB 
(rms). The ping duration would be up to 64 ms, and the ping interval 
would be 1 second. A common mode of operation is a broadcast five 
pulses at 1 second intervals followed by a 5 second pause. The sub-
bottom profiler would be capable of reaching depths of 10,000 m 
(32,808.4 ft).
    Acoustic Locator (Pinger)--A pinger would be deployed with certain 
instruments and equipment (e.g., heat-flow probe) so these devices can 
be located in the event they become detached from their lines. The 
pinger used in the heat-flow measurement activities would be the 
Datasonics model BFP-312HP. A pinger typically operates at a frequency 
of 32.8 kHz, generates a 5 ms pulse per second (10 pulses over a 10 
second period), and has an acoustical output of 210 dB re 1 [mu]Pa 
(rms). The pinger would be used during heat-flow measurement operations 
only. It would operate continuously during each heat-flow probe 
deployment. Each heat-flow probe measurement would last approximately 
24 hours.

Heat-Flow Probe Deployment

    Heat-flow measurements would be made using a ``violin-bow'' probe 
with 11 thermistors that provides real time (analog) telemetry of the 
thermal gradient and in-situ thermal conductivity. The heat-flow probe 
that would be used on the Revelle consists of a lance 6 centimeter (cm) 
(2.4 in) in diameter and 3.5 m (11.5 ft) long, a sensor tube housing 
thermistors and heater wires, and a 560 kg (1,234.6 lb) weight stand. 
The probe would be lowered to the bottom, and a 12 kHz pinger attached 
to the wire approximately 50 m (164 ft) above the instrument would 
monitor the distance between the probe and bottom. The probe would be 
driven into the sediment by gravity, and temperatures within the 
sediment would be measured with equally spaced thermistors. On 
completion of a measurement, the instrument would be hoisted 100 to 500 
m (328.1 to 1,640.4 ft) above the sediment, the ship is maneuvered to a 
new position, and the process is repeated. Heat-flow measurements can 
generally be made at a rate of 1 to 2 hours per measurement, 
approximately 15 minutes for the actual measurement and 45 to 90 
minutes to reposition the ship and probe. Internal power allows 20 to 
24 measurements during a single lowering of the tool, with profiles 
lasting as long as 48 hours. Proposed heat-flow measurements would have 
a nominal spacing of 0.5 to 1 km (0.3 to 0.5 nmi), which would be 
decreased in areas of significant basement relief or of large changes 
in gradient. Heat flow transect locations are shown in Figure 1 of the 
IHA application, and details of the probe and its deployment are given 
in Section (f) of the IHA application. In total, approximately 200 
heat-flow measurements would be made.

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

    Few scientific systematic surveys for marine mammals have been 
conducted in the waters of New Zealand, and these mainly consist of 
single-species surveys in shallow coastal waters (e.g., Dawson et al., 
2004; Slooten et al., 2004, 2006). Large-scale, multi-species marine 
mammal surveys are lacking. Various sources for data on sightings in 
the proposed study area were used to describe the occurrence of marine 
mammals in the waters of New Zealand, such as opportunistic sighting 
records presented in previous reports (including the New Zealand 
Department of Conservation marine mammals sighting database) considered 
in evaluating potential marine mammals in the proposed action area.
    New Zealand is considered a ``hotspot'' for marine mammal species 
richness (Kaschner et al., 2011). The marine mammals that generally 
occur in the proposed action area belong to three taxonomic groups: 
Mysticetes (baleen whales), odontocetes (toothed whales), and pinnipeds 
(seals and sea lions). The marine mammal species that could potentially 
occur within the Southwest Pacific Ocean in proximity to the proposed 
action area East of New Zealand include 30 species of cetaceans (21 
odontocetes and 9 mysticetes) and 2 species of pinnipeds (32 total 
species of marine mammals).
    Marine mammal species likely to be encountered in the proposed 
study area that are listed as endangered under the U.S. Endangered 
Species Act of 1973 (ESA; 16 U.S.C. 1531 et seq.), includes the 
southern right (Eubalaena australis), humpback (Megaptera 
novaeangliae), sei (Balaenoptera borealis), fin (Balaenoptera 
physalus), blue (Balaenoptera musculus), and sperm (Physeter 
macrocephalus) whale. The Maui's dolphin (Cephalorhynchus hectori maui) 
and New Zealand sea lion (Phocartos hookeri) are two other species are 
ranked as ``nationally critical'' in New Zealand (Baker et al., 2010). 
Maui's dolphin is only found along the west coast of the North Island. 
The northern range of the New Zealand sea lion is not expected to 
extend to the proposed study area based on New Zealand's National 
Aquatic Biodiversity Information System (NABIS, 2014) and is not 
considered further.
    In addition to the marine mammal species known to occur in the 
Southwest Pacific Ocean off the east coast of New Zealand, there are 18 
species of marine mammals (12 cetacean and 6 pinniped species) with 
ranges that are known to potentially occur in the waters of the 
proposed study area, but they are categorized as ``vagrant'' under the 
New Zealand Threat Classification System (Baker et al., 2010). These 
include: Dwarf sperm whale (Kogia sima), Arnoux's beaked whale 
(Berardius arnouxi), ginkgo-toothed beaked whale (Mesoplodon 
ginkgodens), pygmy beaked whale (Mesoplodon peruvianis), Type B, C, and 
D killer whale (Orcinus orca), melon-headed whale (Peponocephala 
electra), Risso's dolphin (Grampus griseus), Fraser's dolphin 
(Lagenodelphis hosei), pantropical spotted dolphin (Stenella 
attenuata), striped dolphin (Stenella coeruleoalba), rough-toothed 
dolphin (Steno bredanensis), spectacled

[[Page 15067]]

porpoise (Phocoena dioptrica), Antarctic fur seal (Arctocephalus 
gazelle), Subantarctic fur seal (Arctocephalus tropicalis), crabeater 
seal (Lobodon carcinophagus), leopard seal (Hydrurga leptonyx), Ross 
seal (Ommatophoca rossi), and Weddell seal (Leptonychotes weddellii). 
According to Jefferson et al. (2008), the distributional range of 
Hubb's beaked whale (Mesoplodon carlhubbsi) and True's beaked whale 
(Mesoplodon mirus) may also include New Zealand waters. There are no 
records of Hubb's beaked whale in New Zealand, and only a single record 
of True's beaked whale, which stranded on the west coast of South 
Island in November 2011 (Constantine et al., 2014). The spinner 
dolphin's (Stenella longirostris) range includes tropical and 
subtropical zones 40[deg] North to 40[deg] South, but would be 
considered vagrant as well. However, these species are not expected to 
occur where the proposed activities would take place. These species are 
not considered further in this document. Table 3 (below) presents 
information on the habitat, occurrence, distribution, abundance, 
population, and conservation status of the species of marine mammals 
that may occur in the proposed study area during May to June 2015.

Table 3--The Habitat, Occurrence, Range, Regional Abundance, and Conservation Status of Marine Mammals That May Occur in or Near the Proposed Low-Energy
                                         Seismic Survey Area in the Southwest Pacific Ocean, East of New Zealand
                                          [See text and tables 2 in SIO's IHA application for further details]
--------------------------------------------------------------------------------------------------------------------------------------------------------
              Species                        Habitat                Occurrence                 Range            Population estimate     ESA 1    MMPA 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Mysticetes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Southern right whale (Eubalaena      Coastal, shelf,         Common.................  Circumpolar 20 to       8,000 \3\ to 15,000           EN         D
 australis).                          pelagic.                                         55[deg] South.          \4\--Worldwide 12,000
                                                                                                               \12\--Southern
                                                                                                               Hemisphere 2,700
                                                                                                               \12\--Sub-Antarctic
                                                                                                               New Zealand.
Pygmy right whale (Caperea           Pelagic and coastal...  Rare...................  Circumpolar 30 to       NA....................        NL        NC
 marginata).                                                                           55[deg] South.
Humpback whale (Megaptera            Pelagic, nearshore      Common.................  Cosmopolitan Migratory  35,000 to 42,000 3 12--       EN         D
 novaeangliae).                       waters, and banks.                                                       Southern Hemisphere.
Minke whale (Balaenoptera            Pelagic and coastal...  Uncommon...............  Circumpolar--Southern   720,0000 to 750,000 12        NL        NC
 acutorostrata including dwarf sub-                                                    Hemisphere to 65[deg]   14 15--Southern
 species).                                                                             South.                  Hemisphere.
Antarctic minke whale (Balaenoptera  Pelagic, ice floes,     Uncommon...............  7[deg] South to ice     720,000 to 750,000 12         NL        NC
 bonaerensis).                        coastal.                                         edge (usually 20 to     14 15--Southern
                                                                                       65[deg] South).         Hemisphere.
Bryde's whale (Balaenoptera edeni).  Pelagic and coastal...  Rare...................  Circumglobal--Tropical  At least 30,000 to            NL        NC
                                                                                       and Subtropical Zones.  40,000 \3\--Worldwide
                                                                                                               21,000 \12\--
                                                                                                               Northwestern Pacific
                                                                                                               Ocean 48,109 \13\.
Sei whale (Balaenoptera borealis)..  Primarily offshore,     Uncommon...............  Migratory, Feeding      80,000 \3\--Worldwide         EN         D
                                      pelagic.                                         Concentration 40 to     10,000 \14\--South of
                                                                                       50[deg] South.          Antarctic Convergence.
Fin whale (Balaenoptera physalus)..  Continental slope,      Uncommon...............  Cosmopolitan,           140,000 \3\--Worldwide        EN         D
                                      pelagic.                                         Migratory.              15,000 \14\--South of
                                                                                                               Antarctic Convergence.
Blue whale (Balaenoptera musculus;   Pelagic, shelf,         Uncommon...............  Migratory Pygmy blue    8,000 to 9,000 \3\--          EN         D
 including pygmy blue whale           coastal.                                         whale--North of         Worldwide 2,300 \12\--
 [Balaenoptera musculus                                                                Antarctic Convergence   True Southern
 brevicauda]).                                                                         55[deg] South.          Hemisphere 1,500
                                                                                                               \14\--Pygmy.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Odontocetes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sperm whale (Physeter                Pelagic, deep sea.....  Common.................  Cosmopolitan,           360,000 \3\--Worldwide        EN         D
 macrocephalus).                                                                       Migratory.              30,000 \13\--South of
                                                                                                               Antarctic Convergence.
Dwarf sperm whale (Kogia sima).....  Shelf, Pelagic........  Vagrant................  Circumglobal--Tropical  NA....................        NL        NC
                                                                                       and Temperate Zones.
Pygmy sperm whale (Kogia breviceps)  Shelf, Pelagic........  Uncommon...............  Circumglobal--Temperat  NA....................        NL        NC
                                                                                       e Zones.
Arnoux's beaked whale (Berardius     Pelagic...............  Vagrant................  Circumpolar in          NA....................        NL        NC
 arnuxii).                                                                             Southern Hemisphere,
                                                                                       24 to 78[deg] South.
Cuvier's beaked whale (Ziphius       Pelagic...............  Uncommon...............  Cosmopolitan..........  600,000 14 16.........        NL        NC
 cavirostris).
Southern bottlenose whale            Pelagic...............  Rare...................  Circumpolar--30[deg]    500,000 \3\--South of         NL        NC
 (Hyperoodon planifrons).                                                              South to ice edge.      Antarctic Convergence
                                                                                                               600,000 14 16.
Shepherd's beaked whale (Tasmacetus  Pelagic...............  Rare...................  Circumpolar--Cold       600,000 14 16.........        NL        NC
 shepherdi).                                                                           temperate waters
                                                                                       Southern Hemisphere.

[[Page 15068]]

 
Andrew's beaked whale (Mesoplodon    Pelagic...............  Rare...................  Circumpolar--temperate  600,000 14 16.........        NL        NC
 bowdoini).                                                                            waters of Southern
                                                                                       Hemisphere, 32 to
                                                                                       55[deg] South.
Blainville's beaked whale            Pelagic...............  Rare...................  Circumglobal--tropical  600,000 14 16.........        NL        NC
 (Mesoplodon densirostris).                                                            and temperate waters.
Ginkgo-toothed beaked whale          Pelagic...............  Vagrant................  Tropical and Temperate  NA....................        NL        NC
 (Mesoplodon ginkgodens).                                                              waters--Indo-Pacific
                                                                                       Ocean.
Gray's beaked whale (Mesoplodon      Pelagic...............  Common.................  30[deg] South to        600,000 14 16.........        NL        NC
 grayi).                                                                               Antarctic waters.
Hector's beaked whale (Mesoplodon    Pelagic...............  Rare...................  Circumpolar--cool       600,000 14 16.........        NL        NC
 hectori).                                                                             temperate waters of
                                                                                       Southern Hemisphere.
Hubb's beaked whale (Mesoplodon      Pelagic...............  Vagrant................  North Pacific Ocean...  NA....................        NL        NC
 carlhubbsi).
Pygmy beaked whale (Mesoplodon       Pelagic...............  Vagrant................  28[deg] North to        NA....................        NL        NC
 peruvianis).                                                                          30[deg] South in
                                                                                       Pacific Ocean.
Spade-toothed beaked whale           Pelagic...............  Rare...................  Circumantarctic.......  600,000 14 16.........        NL        NC
 (Mesoplodon traversii).
Strap-toothed beaked whale           Pelagic...............  Uncommon...............  30[deg] South to        600,000 14 16.........        NL        NC
 (Mesoplodon layardii).                                                                Antarctic Convergence.
True's beaked whale (Mesoplodon      Pelagic...............  Vagrant................  Anti-tropical in        NA....................        NL        NC
 mirus).                                                                               Northern and Southern
                                                                                       Hemisphere.
Killer whale (Orcinus orca)........  Pelagic, shelf,         Common.................  Cosmopolitan..........  80,000 \3\--South of          NL        NC
                                      coastal, pack ice.                                                       Antarctic Convergence.
False killer whale (Pseudorca        Pelagic, shelf,         Uncommon...............  Circumglobal--tropical  NA....................        NL        NC
 crassidens).                         coastal.                                         and warmer temperate
                                                                                       water.
Long-finned pilot whale              Pelagic, shelf,         Common.................  Circumpolar--19 to      200,000 3 5 14--South         NL        NC
 (Globicephala melas).                coastal.                                         68[deg] South in        of Antarctic
                                                                                       Southern Hemisphere.    Convergence.
Short-finned pilot whale             Pelagic, shelf,         Uncommon...............  Circumglobal--50[deg]   At least 600,000 \3\--        NL        NC
 (Globicephala macrocephalus).        coastal.                                         North to 40[deg]        Worldwide.
                                                                                       South.
Melon-headed whale (Peponocephala    Pelagic, shelf,         Vagrant................  Circumglocal--40[deg]   45,000 \3\--Eastern           NL        NC
 electra).                            coastal.                                         North to 35[deg]        Tropical Pacific
                                                                                       South.                  Ocean.
Bottlenose dolphin (Tursiops         Coastal, shelf,         Common.................  45[deg] North to        At least 614,000 \3\--    NL, *C        NC
 truncatus).                          offshore.                                        45[deg] South.          Worldwide.
Dusky dolphin (Lagenorhynchus        Shelf, slope..........  Common.................  Temperate waters--      12,000 to 20,000 \17\--       NL        NC
 obscurus).                                                                            Southern Hemisphere.    New Zealand.
Fraser's dolphin (Lagenodelphis      Pelagic...............  Vagrant................  Pantropical--30[deg]    289,000 \3\--Eastern          NL        NC
 hosei).                                                                               North to 30[deg]        Tropical Pacific
                                                                                       South.                  Ocean.
Hector's dolphin (Cephalorhynchus    Nearshore.............  Rare...................  Shallow coastal         7,400 \17\............         C        NC
 hectori; including Maui's dolphin                                                     waters--New Zealand
 subspecies [C. h. maui]).                                                             (Maui's dolpin--west
                                                                                       North Island).
Hourglass dolphin (Lagenorhynchus    Pelagic, ice edge.....  Uncommon...............  33[deg] South to pack   144,000 \3\ to 150,000        NL        NC
 cruciger).                                                                            ice.                    \14\--South of
                                                                                                               Antarctic Convergence.
Pantropical spotted dolphin          Coastal, shelf, slope.  Vagrant................  Circumglobal--40[deg]   At least 2,000,000            NL        NC
 (Stenella attenuata).                                                                 North to 40[deg]        \3\--Worldwide.
                                                                                       South.
Spinner dolphin (Stenella            Mainly nearshore......  Vagrant................  Circumglobal--40[deg]   At least 1,200,000            NL        NC
 longirostris).                                                                        North to 40[deg]        \3\--Worldwide.
                                                                                       South.
Striped dolphin (Stenella            Off continental shelf,  Vagrant................  Circumglobal--50 to 40  At least 1,100,000            NL        NC
 coeruleoalba).                       convergence zones,                               South.                  \3\--Worldwide.
                                      upwelling.
Risso's dolphin (Grampus griseus)..  Slope, Pelagic........  Vagrant................  Circumglobal--Tropical  At least 330,000 \3\--        NL        NC
                                                                                       and Temperate waters.   Worldwide.
Rough-toothed dolphin (Steno         Pelagic...............  Vagrant................  Circumglobal--40[deg]   NA....................        NL        NC
 bredanensis).                                                                         North to 35[deg]
                                                                                       South.

[[Page 15069]]

 
Short-beaked common dolphin          Pelagic...............  Common.................  Circumglobal--tropical  At least 3,500,000            NL        NC
 (Delphinus delphis).                                                                  and warm temperate      \3\--Worldwide.
                                                                                       waters.
Southern right whale dolphin         Pelagic...............  Uncommon...............  12 to 65[deg] South...  NA....................        NL        NC
 (Lissodelphis peronii).
Spectacled porpoise (Phocoena        Coastal, pelagic......  Vagrant................  Circumpolar--Southern   NA....................        NL        NC
 dioptrica).                                                                           Hemisphere.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Pinnipeds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Crabeater seal (Lobodon              Coastal, pack ice.....  Vagrant................  Circumpolar--Antarctic  5,000,000 to                  NL        NC
 carcinophaga).                                                                                                15,000,000 3 6--
                                                                                                               Worldwide.
Leopard seal (Hydrurga leptonyx)...  Pack ice, sub-          Vagrant................  Sub-Antarctic islands   220,000 to 440,000 3          NL        NC
                                      Antarctic islands.                               to pack ice.            7--Worldwide.
Ross seal (Ommatophoca rossii).....  Pack ice, smooth ice    Vagrant................  Circumpolar--Antarctic  130,000 \3\ 20,000 to         NL        NC
                                      floes, pelagic.                                                          220,000 \11\--
                                                                                                               Worldwide.
Weddell seal (Leptonychotes          Fast ice, pack ice,     Vagrant................  Circumpolar--Southern   500,000 to 1,000,000 3        NL        NC
 weddellii).                          sub-Antarctic islands.                           Hemisphere.             8--Worldwide.
Southern elephant seal (Mirounga     Coastal, pelagic, sub-  Uncommon...............  Circumpolar--Antarctic  640,000 \9\ to 650,000        NL        NC
 leonina).                            Antarctic waters.                                Convergence to pack     \3\--Worldwide
                                                                                       ice.                    470,000--South
                                                                                                               Georgia Island \11\
                                                                                                               607,000 \17\.
Antarctic fur seal (Arctocephalus    Shelf, rocky habitats.  Vagrant................  Sub-Antarctic islands   1,600,000 \10\ to             NL        NC
 gazella).                                                                             to pack ice edge.       3,000,000 \3\--
                                                                                                               Worldwide.
New Zealand fur seal (Arctocephalus  Rocky habitats, sub-    Common.................  North and South         135,000 \3\--Worldwide        NL        NC
 forsteri).                           Antarctic islands.                               Islands, New Zealand    50,000 to 100,000
                                                                                       Southern and Western    \18\--New Zealand.
                                                                                       Australia.
Subantarctic fur seal                Shelf, rocky habitats.  Vagrant................  Subtropical front to    Greater than 310,000          NL        NC
 (Arctocephalus tropicalis).                                                           sub-Antarctic islands   \3\--Worldwide.
                                                                                       and Antarctica.
New Zealand sea lion (Phocarctos     Shelf, rocky habitats.  Rare...................  Sub-Antarctic islands   12,500 \3\............        NL        NC
 hookeri).                                                                             south of New Zealand.
--------------------------------------------------------------------------------------------------------------------------------------------------------
NA = Not available or not assessed.
* Fjordland population.
\1\ U.S. Endangered Species Act: EN = Endangered, T = Threatened, DL = Delisted, NL = Not listed, C = Candidate.
\2\ U.S. Marine Mammal Protection Act: D = Depleted, S = Strategic, NC = Not Classified.
\3\ Jefferson et al., 2008.
\4\ Kenney, 2009.
\5\ Olson, 2009.
\6\ Bengston, 2009.
\7\ Rogers, 2009.
\8\ Thomas and Terhune, 2009.
\9\ Hindell and Perrin, 2009.
\10\ Arnould, 2009.
\11\ Academic Press, 2009.
\12\ IWC, 2014.
\13\ IWC, 1981.
\14\ Boyd, 2002.
\15\ Dwarf and Antarctic minke whale combined.
\16\ All Antarctic beaked whales combined.
\17\ New Zealand Department of Conservation.
\18\ Suisted and Neale, 2004.

    Refer to sections 3 and 4 of SIO's IHA application for detailed 
information regarding the abundance and distribution, population 
status, and life history and behavior of these marine mammal species 
and their occurrence in the proposed action area. The IHA application 
also presents how SIO calculated the estimated densities for the marine 
mammals in the proposed study area. NMFS has reviewed these data and 
determined them to be the best available scientific information for the 
purposes of the proposed IHA.

Potential Effects of the Proposed Specified Activity on Marine Mammals

    This section includes a summary and discussion of the ways that the 
types of stressors associated with the specified activity (e.g., 
seismic airgun operation, vessel movement, and gear deployment) have 
been thought to impact marine mammals. This discussion may also include 
reactions that we consider to rise to the level of a take and those 
that we do not consider to rise to the level of take (for example, with 
acoustics, we may include a discussion of studies that showed animals 
not reacting at all to sound or exhibiting barely measureable 
avoidance). This section is intended as a background of potential 
effects and

[[Page 15070]]

does not consider either the specific manner in which this activity 
would be carried out or the mitigation that would be implemented, and 
how either of those would shape the anticipated impacts from this 
specific activity. The ``Estimated Take by Incidental Harassment'' 
section later in this document would include a quantitative analysis of 
the number of individuals that are expected to be taken by this 
activity. The ``Negligible Impact Analysis'' section will include the 
analysis of how this specific activity will impact marine mammals and 
will consider the content of this section, the ``Estimated Take by 
Incidental Harassment'' section, the ``Proposed Mitigation'' section, 
and the ``Anticipated Effects on Marine Mammal Habitat'' section to 
draw conclusions regarding the likely impacts of this activity on the 
reproductive success or survivorship of individuals and from that on 
the affected marine mammal populations or stocks.
    When considering the influence of various kinds of sound on the 
marine environment, it is necessary to understand that different kinds 
of marine life are sensitive to different frequencies of sound. Based 
on available behavioral data, audiograms have been derived using 
auditory evoked potentials, anatomical modeling, and other data, 
Southall et al. (2007) designate ``functional hearing groups'' for 
marine mammals and estimate the lower and upper frequencies of 
functional hearing of the groups. The functional groups and the 
associated frequencies are indicated below (though animals are less 
sensitive to sounds at the outer edge of their functional range and 
most sensitive to sounds of frequencies within a smaller range 
somewhere in the middle of their functional hearing range):
     Low-frequency cetaceans (13 species of mysticetes): 
Functional hearing is estimated to occur between approximately 7 Hz and 
30 kHz;
     Mid-frequency cetaceans (32 species of dolphins, six 
species of larger toothed whales, and 19 species of beaked and 
bottlenose whales): Functional hearing is estimated to occur between 
approximately 150 Hz and 160 kHz;
     High-frequency cetaceans (eight species of true porpoises, 
six species of river dolphins, Kogia spp., the franciscana [Pontoporia 
blainvillei], and four species of cephalorhynchids): Functional hearing 
is estimated to occur between approximately 200 Hz and 180 kHz; and
     Phocid pinnipeds in water: Functional hearing is estimated 
to occur between approximately 75 Hz and 100 kHz;
     Otariid pinnipeds in water: Functional hearing is 
estimated to occur between approximately 100 Hz and 40 kHz.
    As mentioned previously in this document, 32 marine mammal species 
(30 cetacean and 2 pinniped species) are likely to occur in the 
proposed low-energy seismic survey area. Of the 30 cetacean species 
likely to occur in SIO's proposed action area, 9 are classified as low-
frequency cetaceans (southern right, pygmy right, humpback, minke, 
Antarctic minke, Bryde's, sei, fin, and blue whale), 20 are classified 
as mid-frequency cetaceans (sperm, Cuvier's beaked, Shepherd's beaked, 
southern bottlenose, Andrew's beaked, Blainville's beaked, Gray's 
beaked, Hector's beaked, spade-toothed beaked, strap-toothed beaked, 
killer, false killer, long-finned pilot, and short-finned pilot whale, 
and bottlenose, dusky, Hector's, hourglass, short-beaked common, and 
southern right whale dolphin), and 1 is classified as high-frequency 
cetaceans (pygmy sperm whale) (Southall et al., 2007). Of the 2 
pinniped species likely to occur in SIO's proposed action area, 1 is 
classified as phocid (southern elephant seal) and 1 is classified as 
otariid (New Zealand fur seal) (Southall et al., 2007). A species 
functional hearing group is a consideration when we analyze the effects 
of exposure to sound on marine mammals.
    Acoustic stimuli generated by the operation of the airguns, which 
introduce sound into the marine environment, have the potential to 
cause Level B harassment of marine mammals in the proposed study area. 
The effects of sounds from airgun operations might include one or more 
of the following: Tolerance, masking of natural sounds, behavioral 
disturbance, temporary or permanent hearing impairment, or non-auditory 
physical or physiological effects (Richardson et al., 1995; Gordon et 
al., 2004; Nowacek et al., 2007; Southall et al., 2007). Permanent 
hearing impairment, in the unlikely event that it occurred, would 
constitute injury, but temporary threshold shift (TTS) is not an injury 
(Southall et al., 2007; Le Prell, 2012). Although the possibility 
cannot be entirely excluded, it is unlikely that the proposed project 
would result in any cases of temporary or permanent hearing impairment, 
or any significant non-auditory physical or physiological effects. 
Based on the available data and studies described here, some behavioral 
disturbance is expected. A more comprehensive review of these issues 
can be found in the NSF/USGS PEIS (2011) and L-DEO's ``Final 
Environmental Assessment of a Marine Geophysical Survey by the R/V 
Marcus G. Langseth in the Atlantic Ocean off Cape Hatteras, September 
to October 2014.''

Tolerance

    Richardson et al. (1995) defines tolerance as the occurrence of 
marine mammals in areas where they are exposed to human activities or 
man-made noise. In many cases, tolerance develops by the animal 
habituating to the stimulus (i.e., the gradual waning of responses to a 
repeated or ongoing stimulus) (Richardson et al., 1995; Thorpe, 1963), 
but because of ecological or physiological requirements, many marine 
animals may need to remain in areas where they are exposed to chronic 
stimuli (Richardson et al., 1995).
    Numerous studies have shown that pulsed sounds from airguns are 
often readily detectable in the water at distances of many kilometers 
(Nieukirk et al., 2012). Several studies have shown that marine mammals 
at distances more than a few kilometers from operating seismic vessels 
often show no apparent response. That is often true even in cases when 
the pulsed sounds must be readily audible to the animals based on 
measured received levels and the hearing sensitivity of the marine 
mammal group. Although various baleen whales and toothed whales, and 
(less frequently) pinnipeds have been shown to react behaviorally to 
airgun pulses under some conditions, at other times marine mammals of 
all three types have shown no overt reactions. The relative 
responsiveness of baleen and toothed whales are quite variable.

Masking

    The term masking refers to the inability of a subject to recognize 
the occurrence of an acoustic stimulus as a result of the interference 
of another acoustic stimulus (Clark et al., 2009). Introduced 
underwater sound may, through masking, reduce the effective 
communication distance of a marine mammal species if the frequency of 
the source is close to that used as a signal by the marine mammal, and 
if the anthropogenic sound is present for a significant fraction of the 
time (Richardson et al., 1995).
    The airguns for the proposed low-energy seismic survey have 
dominant frequency components of 0 to 188 Hz. This frequency range 
fully overlaps the lower part of the frequency range of odontocete 
calls and/or functional hearing (full range about 150 Hz to 180 kHz). 
Airguns also produce a small portion of their sound at mid and high

[[Page 15071]]

frequencies that overlap most, if not all, frequencies produced by 
odontocetes. While it is assumed that mysticetes can detect acoustic 
impulses from airguns and vessel sounds (Richardson et al., 1995a), 
sub-bottom profilers, and most of the multi-beam echosounders would 
likely be detectable by some mysticetes based on presumed mysticete 
hearing sensitivity. Odontocetes are presumably more sensitive to mid 
to high frequencies produced by the multi-beam echosounders and sub-
bottom profilers than to the dominant low frequencies produced by the 
airguns and vessel. A more comprehensive review of the relevant 
background information for odontocetes appears in Section 3.6.4.3, 
Section 3.7.4.3 and Appendix E of the NSF/USGS PEIS (2011).
    Masking effects of pulsed sounds (even from large arrays of 
airguns) on marine mammal calls and other natural sounds are expected 
to be limited. Because of the intermittent nature and low duty cycle of 
seismic airgun pulses, animals can emit and receive sounds in the 
relatively quiet intervals between pulses. However, in some situations, 
reverberation occurs for much or the entire interval between pulses 
(e.g., Simard et al., 2005; Clark and Gagnon, 2006) which could mask 
calls. Situations with prolonged strong reverberation are infrequent. 
However, it is common for reverberation to cause some lesser degree of 
elevation of the background level between airgun pulses (Gedamke, 2011; 
Guerra et al., 2011, 2013), and this weaker reverberation presumably 
reduces the detection range of calls and other natural sound to some 
degree. Guerra et al. (2013) reported that ambient noise levels between 
seismic pulses were elevated because of reverberation at ranges of 50 
km (27 nmi) from the seismic source. Based on measurements in deep 
water of the Southern Ocean, Gedamke (2011) estimated that the slight 
elevation of background levels during intervals between pulses reduced 
blue and fin whale communication space by as much as 36 to 51% when a 
seismic survey was operating 450 to 2,800 km (243 to 1,511.9 nmi) away. 
Based on preliminary modeling, Wittekind et al. (2013) reported that 
airgun sounds could reduce the communication range of blue and fin 
whales 2,000 km (1,079.9 nmi) from the seismic source. Klinck et al. 
(2012) also found reverberation effects between pulses. Nieukirk et al. 
(2012) and Blackwell et al. (2013) noted the potential for masking 
effects from seismic surveys on large whales.
    Some baleen and toothed whales are known to continue calling in the 
presence of seismic pulses, and their calls can usually be heard 
between the seismic pulses (e.g., Richardson et al., 1986; McDonald et 
al., 1995; Greene et al., 1999; Nieukirk et al., 2004, 2012; Smultea et 
al., 2004; Holst et al., 2005a,b, 2006; and Dunn and Hernandez, 2009). 
However, Clark and Gagnon (2006) reported that fin whales in the North 
Atlantic Ocean went silent for an extended period starting soon after 
the onset of a seismic survey in the area. Similarly, there has been 
one report that sperm whales ceased calling when exposed to pulses from 
a very distant seismic ship (Bowles et al., 1994). However, more recent 
studies found that they continued calling in the presence of seismic 
pulses (Madsen et al., 2002; Tyack et al., 2003; Smultea et al., 2004; 
Holst et al., 2006; and Jochens et al., 2008). Cerchio et al. (2014) 
suggested that the breeding display of humpback whales off Angola could 
have been disrupted by seismic sounds, as singing activity declined 
with increasing received levels. In addition, some cetaceans are known 
to change their calling rates, shift their peak frequencies, or 
otherwise modify their vocal behavior in response to airgun sounds (Di 
Iorio and Clark, 2010; Castellote et al., 2012; Blackwell et al., 
2013). Di Iorio and Clark (2009) found evidence of increased calling by 
blue whales during operations by a lower-energy seismic source (i.e., 
sparker). The hearing systems of baleen whales are undoubtedly more 
sensitive to low-frequency sounds than are the ears of small 
odontocetes that have been studied directly (MacGillivary et al., 
2013). Dolphins and porpoises commonly are heard calling while airguns 
are operating (e.g., Gordon et al., 2004; Smultea et al., 2004; Holst 
et al., 2005a, b; and Potter et al., 2007). The sounds important to 
small odontocetes are predominantly at much higher frequencies than are 
the dominant components of airgun sounds, thus limiting the potential 
for masking.
    Pinnipeds have the most sensitive hearing and/or produce most of 
their sounds in frequencies higher than the dominant components of 
airgun sound, but there is some overlap in the frequencies of the 
airgun pulses and the calls. However, the intermittent nature of airgun 
pules presumably reduces the potential for masking.
    Marine mammals are thought to be able to compensate for masking by 
adjusting their acoustic behavior through shifting call frequencies, 
increasing call volume, and increasing vocalization rates. For example 
blue whales are found to increase call rates when exposed to noise from 
seismic surveys in the St. Lawrence Estuary (Di Iorio and Clark, 2009). 
The North Atlantic right whales (Eubalaena glacialis) exposed to high 
shipping noise increased call frequency (Parks et al., 2007), while 
some humpback whales respond to low-frequency active sonar playbacks by 
increasing song length (Miller et al., 2000). In general, NMFS expects 
the masking effects of seismic pulses to be minor, given the normally 
intermittent nature of seismic pulses.

Behavioral Disturbance

    Marine mammals may behaviorally react to sound when exposed to 
anthropogenic noise. Disturbance includes a variety of effects, 
including subtle to conspicuous changes in behavior, movement, and 
displacement. Reactions to sound, if any, depend on species, state of 
maturity, experience, current activity, reproductive state, time of 
day, and many other factors (Richardson et al., 1995; Wartzok et al., 
2004; Southall et al., 2007; Weilgart, 2007; Ellison et al., 2012). 
These behavioral reactions are often shown as: Changing durations of 
surfacing and dives, number of blows per surfacing, or moving direction 
and/or speed; reduced/increased vocal activities; changing/cessation of 
certain behavioral activities (such as socializing or feeding); visible 
startle response or aggressive behavior (such as tail/fluke slapping or 
jaw clapping); avoidance of areas where noise sources are located; and/
or flight responses (e.g., pinnipeds flushing into the water from haul-
outs or rookeries). If a marine mammal does react briefly to an 
underwater sound by changing its behavior or moving a small distance, 
the impacts of the change are unlikely to be significant to the 
individual, let alone the stock or population (New et al., 2013). 
However, if a sound source displaces marine mammals from an important 
feeding or breeding area for a prolonged period, impacts on individuals 
and populations could be significant (e.g., Lusseau and Bejder, 2007; 
Weilgart, 2007).
    The biological significance of many of these behavioral 
disturbances is difficult to predict, especially if the detected 
disturbances appear minor. However, the consequences of behavioral 
modification could be expected to be biologically significant if the 
change affects growth, survival, and/or reproduction. Some of these 
significant behavioral modifications include:
     Change in diving/surfacing patterns (such as those thought 
to be causing beaked whale stranding due to exposure to military mid-
frequency tactical sonar);

[[Page 15072]]

     Habitat abandonment due to loss of desirable acoustic 
environment; and
     Cessation of feeding or social interaction.
    The onset of behavioral disturbance from anthropogenic noise 
depends on both external factors (characteristics of noise sources and 
their paths) and the receiving animals (hearing, motivation, 
experience, demography) and is also difficult to predict (Richardson et 
al., 1995; Southall et al., 2007). Given the many uncertainties in 
predicting the quantity and types of impacts of noise on marine 
mammals, it is common practice to estimate how many mammals would be 
present within a particular distance of industrial activities and/or 
exposed to a particular level of sound. In most cases, this approach 
likely overestimates the numbers of marine mammals that would be 
affected in some biologically-important manner.
    Baleen Whales--Baleen whales generally tend to avoid operating 
airguns, but avoidance radii are quite variable (reviewed in Richardson 
et al., 1995; Gordon et al., 2004). Whales are often reported to show 
no overt reactions to pulses from large arrays of airguns at distances 
beyond a few kilometers, even though the airgun pulses remain well 
above ambient noise levels out to much longer distances. However, 
baleen whales exposed to strong noise pulses from airguns often react 
by deviating from their normal migration route and/or interrupting 
their feeding and moving away. In the cases of migrating gray 
(Eschrichtius robustus) and bowhead (Balaena mysticetus) whales, the 
observed changes in behavior appeared to be of little or no biological 
consequence to the animals (Richardson et al., 1995). They simply 
avoided the sound source by displacing their migration route to varying 
degrees, but within the natural boundaries of the migration corridors 
(Malme et al., 1984; Malme and Miles, 1985; Richardson et al., 1995).
    Studies of gray, bowhead, and humpback whales have shown that 
seismic pulses with received levels of 160 to 170 dB re 1 [mu]Pa (rms) 
seem to cause obvious avoidance behavior in a substantial fraction of 
the animals exposed (Malme et al., 1986, 1988; Richardson et al., 
1995). In many areas, seismic pulses from large arrays of airguns 
diminish to those levels at distances ranging from 4 to 15 km (2.2 to 
8.1 nmi) from the source. A substantial proportion of the baleen whales 
within those distances may show avoidance or other strong behavioral 
reactions to the airgun array. Subtle behavioral changes sometimes 
become evident at somewhat lower received levels, and studies have 
shown that some species of baleen whales, notably bowhead, gray, and 
humpback whales, at times, show strong avoidance at received levels 
lower than 160 to 170 dB re 1 [mu]Pa (rms).
    Researchers have studied the responses of humpback whales to 
seismic surveys during migration, feeding during the summer months, 
breeding while offshore from Angola, and wintering offshore from 
Brazil. McCauley et al. (1998, 2000a) studied the responses of humpback 
whales off western Australia to a full-scale seismic survey with a 16 
airgun array (2,678 in\3\) and to a single airgun (20 in\3\) with 
source level of 227 dB re 1 [mu]Pa (p-p). In the 1998 study, they 
documented that avoidance reactions began at 5 to 8 km (2.7 to 4.3 nmi) 
from the array, and that those reactions kept most pods approximately 3 
to 4 km (1.6 to 2.2 nmi) from the operating seismic boat. In the 2000 
study, they noted localized displacement during migration of 4 to 5 km 
(2.2 to 2.7 nmi) by traveling pods and 7 to 12 km (3.8 to 6.5 nmi) by 
more sensitive resting pods of cow-calf pairs. Avoidance distances with 
respect to the single airgun were smaller but consistent with the 
results from the full array in terms of the received sound levels. The 
mean received level for initial avoidance of an approaching airgun was 
140 dB re 1 [mu]Pa (rms) for humpback pods containing females, and at 
the mean closest point of approach distance the received level was 143 
dB re 1 [mu]Pa (rms). The initial avoidance response generally occurred 
at distances of 5 to 8 km (2.7 to 4.3 nmi) from the airgun array and 2 
km (1.1 nmi) from the single airgun. However, some individual humpback 
whales, especially males, approached within distances of 100 to 400 m 
(328 to 1,312 ft), where the maximum received level was 179 dB re 1 
[mu]Pa (rms). Studies examining the behavioral responses of humpback 
whales to airguns are currently underway off eastern Australia (Cato et 
al., 2011, 2012, 2013).
    Data collected by observers during several seismic surveys in the 
Northwest Atlantic showed that sighting rates of humpback whales were 
significantly greater during non-seismic periods compared with periods 
when a full array was operating (Moulton and Holst, 2010). In addition, 
humpback whales were more likely to swim away and less likely to swim 
towards a vessel during seismic vs. non-seismic periods (Moulton and 
Holst, 2010).
    Humpback whales on their summer feeding grounds in southeast Alaska 
did not exhibit persistent avoidance when exposed to seismic pulses 
from a 1.64-L (100 in\3\) airgun (Malme et al., 1985). Some humpbacks 
seemed ``startled'' at received levels of 150 to 169 dB re 1 [mu]Pa. 
Malme et al. (1985) concluded that there was no clear evidence of 
avoidance, despite the possibility of subtle effects, at received 
levels up to 172 dB re 1 [mu]Pa (rms). However, Moulton and Holst 
(2010) reported that humpback whales monitored during seismic surveys 
in the Northwest Atlantic had lower sighting rates and were most often 
seen swimming away from the vessel during seismic periods compared with 
periods when airguns were silent.
    Studies have suggested that South Atlantic humpback whales 
wintering off Brazil may be displaced or even strand upon exposure to 
seismic surveys (Engel et al., 2004). The evidence for this was 
circumstantial and subject to alternative explanations (IAGC, 2004). 
Also, the evidence was not consistent with subsequent results from the 
same area of Brazil (Parente et al., 2006), or with direct studies of 
humpbacks exposed to seismic surveys in other areas and seasons. After 
allowance for data from subsequent years, there was ``no observable 
direct correlation'' between strandings and seismic surveys (IWC, 2007: 
236).
    There are no reactions of right whales to seismic surveys. However, 
Rolland et al. (2012) suggested that ship noise causes increased stress 
in right whales; they showed that baseline levels of stress-related 
fecal hormone metabolites decreased in North Atlantic right whales with 
a 6 dB decrease in underwater noise from vessels. Wright et al. (2011) 
also reported that sound could be a potential source of stress for 
marine mammals.
    Results from bowhead whales 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 (10.8 to 16.2 nmi) 
from a medium-sized airgun source (Miller et al., 1999; Richardson et 
al., 1999). However, more recent research on bowhead whales 
corroborates earlier evidence that, during the summer feeding season, 
bowheads are not as sensitive to seismic sources (Miller et al., 2005). 
Nonetheless, Robertson et al. (2013) showed that bowheads on their 
summer feeding grounds showed subtle but statistically significant 
changes in surfacing-respiration-dive cycles during exposure to seismic 
sounds, including

[[Page 15073]]

shorter surfacing intervals, shorter dives, and decreased number of 
blows per surface interval.
    Bowhead whale calls detected in the presence and absence of airgun 
sounds have been studied extensively in the Beaufort Sea. Bowheads 
continue to produce calls of the usual types when exposed to airgun 
sounds on their summering grounds, although number of calls detected 
are significantly lower in the presence than in the absence of airgun 
pulses; Blackwell et al. (2013) reported that calling rates in 2007 
declined significantly where received SPLs from airgun sounds were 116 
to 129 dB re 1 [mu]Pa. Thus, bowhead whales in the Beaufort Sea 
apparently decrease their calling rates in response to seismic 
operations, although movement out of the area could also contribute to 
the lower call detection rate (Blackwell et al., 2013).
    A multivariate analysis of factors affecting the distribution of 
calling bowhead whales during their fall migration in 2009 noted that 
the southern edge of the distribution of calling whales was 
significantly closer to shore with increasing levels of airgun sound 
from a seismic survey a few hundred kms to the east of the study area 
(i.e., behind the westward-migrating whales; McDonald et al., 2010, 
2011). It was not known whether this statistical effect represented a 
stronger tendency for quieting of the whales farther offshore in deeper 
water upon exposure to airgun sound, or an actual inshore displacement 
of whales.
    Reactions of migrating and feeding (but not wintering) gray whales 
to seismic surveys have been studied. Malme et al. (1986, 1988) studied 
the responses of feeding eastern Pacific gray whales to pulses from a 
single 100 in\3\ airgun off St. Lawrence Island in the northern Bering 
Sea. They estimated, based on small sample sizes, that 50 percent of 
feeding gray whales stopped feeding at an average received pressure 
level of 173 dB re 1 [mu]Pa on an (approximate) rms basis, and that 10 
percent of feeding whales interrupted feeding at received levels of 163 
dB re 1 [mu]Pa (rms). Those findings were generally consistent with the 
results of experiments conducted on larger numbers of gray whales that 
were migrating along the California coast (Malme et al., 1984; Malme 
and Miles, 1985), and western Pacific gray whales feeding off Sakhalin 
Island, Russia (Wursig et al., 1999; Gailey et al., 2007; Johnson et 
al., 2007; Yazvenko et al., 2007a, b), along with data on gray whales 
off British Columbia (Bain and Williams, 2006).
    Various species of Balaenoptera (blue, sei, fin, and minke whales) 
have occasionally been seen in areas ensonified by airgun pulses 
(Stone, 2003; MacLean and Haley, 2004; Stone and Tasker, 2006), and 
calls from blue and fin whales have been localized in areas with airgun 
operations (e.g., McDonald et al., 1995; Dunn and Hernandez, 2009; 
Castellote et al., 2010). Sightings by observers on seismic vessels off 
the United Kingdom from 1997 to 2000 suggest that, during times of good 
sightability, sighting rates for mysticetes (mainly fin and sei whales) 
were similar when large arrays of airguns were shooting versus 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, 
2012) reported that singing fin whales in the Mediterranean moved away 
from an operating airgun array, and their song notes had low bandwidths 
during periods with versus without airgun sounds.
    Ship-based monitoring studies of baleen whales (including blue, 
fin, sei, minke, and humpback whales) in the Northwest Atlantic found 
that overall, this group had lower sighting rates during seismic vs. 
non-seismic periods (Moulton and Holst, 2010). Baleen whales as a group 
were also seen significantly farther from the vessel during seismic 
compared with non-seismic periods, and they were more often seen to be 
swimming away from the operating seismic vessel (Moulton and Holst, 
2010). Blue and minke whales were initially sighted significantly 
farther from the vessel during seismic operations compared to non-
seismic periods; the same trend was observed for fin whales (Moulton 
and Holst, 2010). Minke whales were most often observed to be swimming 
away from the vessel when seismic operations were underway (Moulton and 
Holst, 2010).
    Data on short-term reactions by cetaceans to impulsive noises are 
not necessarily indicative of long-term or biologically significant 
effects. It is not known whether impulsive sounds affect reproductive 
rate or distribution and habitat use in subsequent days or years. 
However, gray whales have continued to migrate annually along the west 
coast of North America with substantial increases in the population 
over recent years, despite intermittent seismic exploration (and much 
ship traffic) in that area for decades (Appendix A in Malme et al., 
1984; Richardson et al., 1995; Allen and Angliss, 2010). The western 
Pacific gray whale population did not seem affected by a seismic survey 
in its feeding ground during a previous year (Johnson et al., 2007). 
Similarly, bowhead whales have continued to travel to the eastern 
Beaufort Sea each summer, and their numbers have increased notably, 
despite seismic exploration in their summer and autumn range for many 
years (Richardson et al., 1987; Allen and Angliss, 2010).
    Toothed Whales--Little systematic information is available about 
reactions of toothed whales to noise pulses. Few studies similar to the 
more extensive baleen whale/seismic pulse work summarized above have 
been reported for toothed whales. However, there are recent systematic 
studies on sperm whales (e.g., Gordon et al., 2006; Madsen et al., 
2006; Winsor and Mate, 2006; Jochens et al., 2008; Miller et al., 
2009). There is an increasing amount of information about responses of 
various odontocetes to seismic surveys based on monitoring studies 
(e.g., Stone, 2003; Smultea et al., 2004; Moulton and Miller, 2005; 
Bain and Williams, 2006; Holst et al., 2006; Stone and Tasker, 2006; 
Potter et al., 2007; Hauser et al., 2008; Holst and Smultea, 2008; 
Weir, 2008; Barkaszi et al., 2009; Richardson et al., 2009; Moulton and 
Holst, 2010).
    Seismic operators and PSOs on seismic vessels regularly see 
dolphins and other small toothed whales near operating airgun arrays, 
but in general there is a tendency for most delphinids to show some 
avoidance of operating seismic vessels (e.g., Goold, 1996a,b,c; 
Calambokidis and Osmek, 1998; Stone, 2003; Moulton and Miller, 2005; 
Holst et al., 2006; Stone and Tasker, 2006; Weir, 2008; Richardson et 
al., 2009; Barkaszi et al., 2009; Moulton and Holst, 2010; Barry et 
al., 2012). Some dolphins seem to be attracted to the seismic vessel 
and floats, and some ride the bow wave of the seismic vessel even when 
large arrays of airguns are firing (e.g., Moulton and Miller, 2005). 
Nonetheless, small toothed whales more often tend to head away, or to 
maintain a somewhat greater distance from the vessel, when a large 
array of airguns is operating than when it is silent (e.g., Stone and 
Tasker, 2006; Weir, 2008; Barry et al., 2010; Moulton and Holst, 2010). 
In most cases, the avoidance radii for delphinids appear to be small, 
on the order of one km or less, and some individuals show no apparent 
avoidance. Captive bottlenose dolphins (Tursiops truncatus) and beluga 
whales (Delphinapterus leucas) exhibited changes in behavior when 
exposed to

[[Page 15074]]

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.
    Preliminary findings of a monitoring study of narwhals (Monodon 
monoceros) in Melville Bay, Greenland (summer and fall 2012) showed no 
short-term effects of seismic survey activity on narwhal distribution, 
abundance, migration timing, and feeding habits (Heide-Jorgensen et 
al., 2013a). In addition, there were no reported effects on narwhal 
hunting. These findings do not seemingly support a suggestion by Heide-
Jorgensen et al. (2013b) that seismic surveys in Baffin Bay may have 
delayed the migration timing of narwhals, thereby increasing the risk 
of narwhals to ice entrapment.
    Results of 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 (Phocoenoides 
dalli) (Stone, 2003; MacLean and Koski, 2005; Bain and Williams, 2006; 
Stone and Tasker, 2006). Thompson et al. (2013) reported decreased 
densities and reduced acoustic detections of harbor porpoise in 
response to a seismic survey in Moray Firth, Scotland, at ranges of 5 
to 10 km (2.7 to 5.4 nmi) (SPLs of 165 to 172 dB re 1 [mu]Pa; sound 
exposure levels (SELs) of 145 to 151 dB [mu]Pa\2\s); however, animals 
returned to the area within a few hours. Dall's porpoises seem 
relatively tolerant of airgun operations (MacLean and Koski, 2005; Bain 
and Williams, 2006), although they too have been observed to avoid 
large arrays of operating airguns (Calambokidis and Osmek, 1998; Bain 
and Williams, 2006). This apparent difference in responsiveness of 
these two porpoise species is consistent with their relative 
responsiveness to boat traffic and some other acoustic sources 
(Richardson et al., 1995; Southall et al., 2007).
    Most studies of sperm whales exposed to airgun sounds indicate that 
the sperm whale shows considerable tolerance of airgun pulses (e.g., 
Stone, 2003; Moulton et al., 2005, 2006a; Stone and Tasker, 2006; Weir, 
2008). In most cases the whales do not show strong avoidance, and they 
continue to call. However, controlled exposure experiments in the Gulf 
of Mexico indicate that foraging behavior was altered upon exposure to 
airgun sound (Jochens et al., 2008; Miller et al., 2009; Tyack, 2009). 
There are almost no specific data on the behavioral reactions of beaked 
whales to seismic surveys. However, some northern bottlenose whales 
(Hyperoodon ampullatus) remained in the general area and continued to 
produce high-frequency clicks when exposed to sound pulses from distant 
seismic surveys (Gosselin and Lawson, 2004; Laurinolli and Cochrane, 
2005; Simard et al., 2005). Most beaked whales tend to avoid 
approaching vessels of other types (e.g., Wursig et al., 1998). They 
may also dive for an extended period when approached by a vessel (e.g., 
Kasuya, 1986), although it is uncertain how much longer such dives may 
be as compared to dives by undisturbed beaked whales, which also are 
often quite long (Baird et al., 2006; Tyack et al., 2006). Based on a 
single observation, Aguilar-Soto et al. (2006) suggested that foraging 
efficiency of Cuvier's beaked whales may be reduced by close approach 
of vessels. In any event, it is likely that most beaked whales would 
also show strong avoidance of an approaching seismic vessel, although 
this has not been documented explicitly. In fact, Moulton and Holst 
(2010) reported 15 sightings of beaked whales during seismic studies in 
the Northwest Atlantic; seven of those sightings were made at times 
when at least one airgun was operating. There was little evidence to 
indicate that beaked whale behavior was affected by airgun operations; 
sighting rates and distances were similar during seismic and non-
seismic periods (Moulton and Holst, 2010).
    There are increasing indications that some beaked whales tend to 
strand when naval exercises involving mid-frequency sonar operation are 
ongoing nearby (e.g., Simmonds and Lopez-Jurado, 1991; Frantzis, 1998; 
NOAA and USN, 2001; Jepson et al., 2003; Hildebrand, 2005; Barlow and 
Gisiner, 2006; see also the ``Stranding and Mortality'' section in this 
notice). These strandings are apparently a disturbance response, 
although auditory or other injuries or other physiological effects may 
also be involved. Whether beaked whales would ever react similarly to 
seismic surveys is unknown. Seismic survey sounds are quite different 
from those of the sonar in operation during the above-cited incidents.
    Odontocete reactions to large arrays of airguns are variable and, 
at least for delphinids, seem to be confined to a smaller radius than 
has been observed for the more responsive of some mysticetes. However, 
other data suggest that some odontocete species, including harbor 
porpoises, may be more responsive than might be expected given their 
poor low-frequency hearing. Reactions at longer distances may be 
particularly likely when sound propagation conditions are conducive to 
transmission of the higher frequency components of airgun sound to the 
animals' location (DeRuiter et al., 2006; Goold and Coates, 2006; Tyack 
et al., 2006; Potter et al., 2007).
    Pinnipeds--Pinnipeds are not likely to show a strong avoidance 
reaction to the airgun array. Visual monitoring from seismic vessels 
has shown only slight (if any) avoidance of airguns by pinnipeds, and 
only slight (if any) changes in behavior. In the Beaufort Sea, some 
ringed seals avoided an area of 100 m to (at most) a few hundred meters 
around seismic vessels, but many seals remained within 100 to 200 m 
(328 to 656 ft) of the trackline as the operating airgun array passed 
by (e.g., Harris et al., 2001; Moulton and Lawson, 2002; Miller et al., 
2005.). Ringed seal (Pusa hispida) 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 (Phoca 
vitulina) and California sea lions (Zalophus californianus) tended to 
be larger when airguns were operating (Calambokidis and Osmek, 1998). 
Previous telemetry work suggests that avoidance and other behavioral 
reactions by two other species of seals to small airgun sources may be 
stronger than evident to date from visual studies of pinnipeds 
reactions to airguns (Thompson et al., 1998).
    During seismic exploration off Nova Scotia, gray seals (Halichoerus 
grypus) exposed to noise from airguns and linear explosive charges did 
not react strongly (J. Parsons in Greene et al., 1985). Pinnipeds in 
both water and air, sometimes tolerate strong noise pulses from non-
explosive and explosive scaring devices, especially if attracted to the 
area for feeding and reproduction (Mate and Harvey, 1987; Reeves et 
al., 1996). Thus pinnipeds are expected to be rather tolerant of, or 
habituate to, repeated underwater sounds from distant seismic sources, 
at least when the animals are strongly attracted to the area.

Hearing Impairment and Other Physical Effects

    Exposure to high intensity sound for a sufficient duration may 
result in auditory effects such as a noise-induced threshold shift--an 
increase in the auditory threshold after exposure to noise (Finneran, 
Carder, Schlundt, and Ridgway, 2005). Factors that influence the amount 
of threshold shift include the amplitude, duration, frequency

[[Page 15075]]

content, temporal pattern, and energy distribution of noise exposure. 
The magnitude of hearing threshold shift normally decreases over time 
following cessation of the noise exposure. The amount of threshold 
shift just after exposure is called the initial threshold shift. If the 
threshold shift eventually returns to zero (i.e., the threshold returns 
to the pre-exposure value), it is called temporary threshold shift 
(TTS) (Southall et al., 2007). Researchers have studied TTS in certain 
captive odontocetes and pinnipeds exposed to strong sounds (reviewed in 
Southall et al., 2007). However, there has been no specific 
documentation of TTS, let alone permanent hearing damage, i.e., 
permanent threshold shift (PTS), in free-ranging marine mammals exposed 
to sequences of airgun pulses during realistic field conditions.
    Temporary Threshold Shift--TTS is the mildest form of hearing 
impairment that can occur during exposure to a strong sound (Kryter, 
1985). While experiencing TTS, the hearing threshold rises and a sound 
must be stronger in order to be heard. At least in terrestrial mammals, 
TTS can last from minutes or hours to (in cases of strong TTS) days. 
For sound exposures at or somewhat above the TTS threshold, hearing 
sensitivity in both terrestrial and marine mammals recovers rapidly 
after exposure to the noise ends. Few data on sound levels and 
durations necessary to elicit mild TTS have been obtained for marine 
mammals, and none of the published data concern TTS elicited by 
exposure to multiple pulses of sound. Available data on TTS in marine 
mammals are summarized in Southall et al. (2007). Table 2 (above) 
presents the estimated distances from the Revelle's airguns at which 
the received energy level (per pulse, flat-weighted) would be expected 
to be greater than or equal to 180 and 190 dB re 1 [mu]Pa (rms).
    The established 180 and 190 dB (rms) criteria are not considered to 
be the levels above which TTS might occur. Rather, they are the 
received levels above which, in the view of a panel of bioacoustics 
specialists convened by NMFS before TTS measurements for marine mammals 
started to become available, one could not be certain that there would 
be no injurious effects, auditory or otherwise, to marine mammals. NMFS 
also assumes that cetaceans and pinnipeds exposed to levels exceeding 
160 dB re 1 [mu]Pa (rms) may experience Level B harassment.
    For toothed whales, researchers have derived TTS information for 
odontocetes from studies on the bottlenose dolphin and beluga. The 
experiments show that exposure to a single impulse at a received level 
of 207 kPa (or 30 psi, peak-to-peak), which is equivalent to 228 dB re 
1 Pa (peak-to-peak), resulted in a 7 and 6 dB TTS in the beluga whale 
at 0.4 and 30 kHz, respectively. Thresholds returned to within 2 dB of 
the pre-exposure level within 4 minutes of the exposure (Finneran et 
al., 2002). For the one harbor porpoise tested, the received level of 
airgun sound that elicited onset of TTS was lower (Lucke et al., 2009). 
If these results from a single animal are representative, it is 
inappropriate to assume that onset of TTS occurs at similar received 
levels in all odontocetes (cf. Southall et al., 2007). Some cetaceans 
apparently can incur TTS at considerably lower sound exposures than are 
necessary to elicit TTS in the beluga or bottlenose dolphin.
    For baleen whales, there are no data, direct or indirect, on levels 
or properties of sound that are required to induce TTS. The frequencies 
to which baleen whales are most sensitive are assumed to be lower than 
those to which odontocetes are most sensitive, and natural background 
noise levels at those low frequencies tend to be higher. As a result, 
auditory thresholds of baleen whales within their frequency band of 
best hearing are believed to be higher (less sensitive) than are those 
of odontocetes at their best frequencies (Clark and Ellison, 2004). 
From this, it is suspected that received levels causing TTS onset may 
also be higher in baleen whales than those of odontocetes (Southall et 
al., 2007).
    In pinnipeds, researchers have not measured TTS thresholds 
associated with exposure to brief pulses (single or multiple) of 
underwater sound. Initial evidence from more prolonged (non-pulse) 
exposures suggested that some pinnipeds (harbor seals in particular) 
incur TTS at somewhat lower received levels than do small odontocetes 
exposed for similar durations (Kastak et al., 1999, 2005; Ketten et 
al., 2001). The TTS threshold for pulsed sounds has been indirectly 
estimated as being an SEL of approximately 171 dB re 1 
[mu]Pa\2\[middot]s (Southall et al., 2007) which would be equivalent to 
a single pulse with a received level of approximately 181 to 186 dB re 
1 [mu]Pa (rms), or a series of pulses for which the highest rms values 
are a few dB lower. Corresponding values for California sea lions and 
northern elephant seals (Mirounga angustirostris) are likely to be 
higher (Kastak et al., 2005).
    Additional data are needed to determine the received levels at 
which small odontocetes would start to incur TTS upon exposure to 
repeated, low-frequency pulses of airgun sounds with variable received 
levels. To determine how close an airgun array would need to approach 
in order to elicit TTS, one would (as a minimum) need to allow for the 
sequence of distances at which airgun pulses would occur, and for the 
dependence of received SEL on distance in the region of the airgun 
operation (Breitzke and Bohlen, 2010; Laws, 2012). At the present state 
of knowledge, it can be assumed that the effect is directly related to 
total receive energy, although there is recent evidence that auditory 
effects in a given animal are not a simple function of received 
acoustic energy. Frequency, duration of the exposure and occurrence of 
gaps within the exposure can also influence the auditory effect 
(Finneran and Schlundt, 2010, 2011, 2013; Finneran et al., 2010a,b; 
Finneran 2012; Ketten, 2012; Kastelein et al., 2013a).
    The assumption that, in marine mammals, the occurrence and 
magnitude of TTS is a function of cumulative acoustic energy (SEL) is 
probably an oversimplification (Finneran, 2012). Popov et al. (2011) 
examined the effects of fatiguing noise on the hearing threshold of 
Yangtze finless porpoises (Neophocaena phocaenoides) when exposed to 
frequencies of 32 to 128 kHz at 140 to 160 dB re 1 [mu]Pa for 1 to 30 
minutes. They found that an exposure of higher level and shorter 
duration produced a higher TTS than an exposure of equal SEL but of 
lower level and longer duration. Kastelein et al. (2012a,b; 2013b) also 
reported that the equal-energy model is not valid for predicting TTS in 
harbor porpoises or harbor seals.
    Recent data have shown that the SEL required for TTS onset to occur 
increases with intermittent exposures, with some auditory recovery 
during silent periods between (Finneran et al., 2010b; Finneran and 
Schlundt, 2011). Schlundt et al. (2013) reported that the potential for 
seismic surveys using airguns to cause auditory effects on dolphins 
could be lower than previously thought. Based on behavioral tests, 
Finneran et al. (2011) and Schlundt et al. (2013) reported no 
measurable TTS in bottlenose dolphins after exposure to 10 impulses 
from a seismic airgun with a cumulative SEL of approximately 195 dB re 
1 [mu]Pa\2\s; results from auditory evoked potential measurements were 
more variable (Schlundt et al., 2013).
    Recent studies have also shown that the SEL necessary to elicit TTS 
can depend substantially on frequency, with susceptibility to TTS 
increasing with increasing frequency above 3 kHz (Finneran and 
Schlundt, 2010, 2011; Finneran, 2012). When beluga whales

[[Page 15076]]

were exposed to fatiguing noise with sound levels of 165 dB re 1 [mu]Pa 
for durations of 1 to 30 minutes at frequencies of 11.2 to 90 kHz, the 
highest TTS with the longest recovery time was produced by lower 
frequencies (11.2 and 22.5 kHz); TTS effects also gradually increased 
with prolonged exposure time (Popov et al., 2013a). Popov et al. 
(2013b) also reported that TTS produced by exposure to a fatiguing 
noise was larger during the first session (or na[iuml]ve subject state) 
with a beluga whale than TTS that resulted from the same sound in 
subsequent sessions (experienced subject state). Therefore, Supin et 
al. (2013) reported that SEL may not be a valid metric for examining 
fatiguing sounds on beluga whales. Similarly, Nachtigall and Supin 
(2013) reported that false killer whales are able to change their 
hearing sensation levels when exposed to loud sounds, such as warning 
signals or echolocation sounds.
    It is inappropriate to assume that onset of TTS occurs at similar 
received levels in all cetaceans (Southall et al., 2007). Some 
cetaceans could incur TTS at lower sound exposures than are necessary 
to elicit TTS in the beluga or bottlenose dolphin. Based on the best 
available information, Southall et al. (2007) recommended a TTS 
threshold for exposure to a single or multiple pulses of 183 dB re 1 
[mu]Pa\2\s. Tougaard et al. (2013) proposed a TTS criterion of 165 dB 
re 1 [mu]Pa\2\s for porpoises based on data from two recent studies. 
Gedamke et al. (2011), based on preliminary simulation modeling that 
attempted to allow for various uncertainties in assumptions and 
variability around population means, suggested that some baleen whales 
whose closest point of approach to a seismic vessel is 1 km or more 
could experience TTS.
    Permanent Threshold Shift--When PTS occurs, there is physical 
damage to the sound receptors in the ear. In severe cases, there can be 
total or partial deafness, whereas in other cases, the animal has an 
impaired ability to hear sounds in specific frequency ranges (Kryter, 
1985). There is no specific evidence that exposure to pulses of airgun 
sound can cause PTS in any marine mammal, even with large arrays of 
airguns. However, given the possibility that mammals close to an airgun 
array might incur at least mild TTS, there has been further speculation 
about the possibility that some individuals occurring very close to 
airguns might incur PTS (e.g., Richardson et al., 1995, p. 372ff; 
Gedamke et al., 2008). Single or occasional occurrences of mild TTS are 
not indicative of permanent auditory damage, but repeated or (in some 
cases) single exposures to a level well above that causing TTS onset 
might elicit PTS.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals but are assumed to be similar to those in humans and 
other terrestrial mammals (Southall et al., 2007). PTS might occur at a 
received sound level at least several dBs above that inducing mild TTS 
if the animal were exposed to strong sound pulses with rapid rise 
times. Based on data from terrestrial mammals, a precautionary 
assumption is that the PTS threshold for impulse sounds (such as airgun 
pulses as received close to the source) is at least 6 dB higher than 
the TTS threshold on a peak-pressure basis, and probably greater than 6 
dB (Southall et al., 2007). Given the higher level of sound necessary 
to cause PTS as compared with TTS, it is considerably less likely that 
PTS would occur. Baleen whales generally avoid the immediate area 
around operating seismic vessels, as do some other marine mammals.
    Non-auditory Physiological Effects--Non-auditory physiological 
effects or injuries that theoretically might occur in marine mammals 
exposed to strong underwater sound include stress, neurological 
effects, bubble formation, resonance, and other types of organ or 
tissue damage (Cox et al., 2006; Southall et al., 2007). Studies 
examining such effects are limited. However, resonance effects (Gentry, 
2002) and direct noise-induced bubble formations (Crum et al., 2005) 
are implausible in the case of exposure to an impulsive broadband 
source like an airgun array. If seismic surveys disrupt diving patterns 
of deep-diving species, this might perhaps result in bubble formation 
and a form of the bends, as speculated to occur in beaked whales 
exposed to sonar. However, there is no specific evidence of this upon 
exposure to airgun pulses.
    In general, very little is known about the potential for seismic 
survey sounds (or other types of strong underwater sounds) to cause 
non-auditory physical effects in marine mammals. Such effects, if they 
occur at all, would presumably be limited to short distances and to 
activities that extend over a prolonged period. The available data do 
not allow identification of a specific exposure level above which non-
auditory effects can be expected (Southall et al., 2007), or any 
meaningful quantitative predictions of the numbers (if any) of marine 
mammals that might be affected in those ways. Marine mammals that show 
behavioral avoidance of seismic vessels, including most baleen whales, 
some odontocetes, and some pinnipeds, are especially unlikely to incur 
non-auditory physical effects.
    There is no definitive evidence that any of these effects occur 
even for marine mammals in close proximity to large airgun arrays. 
However, Gray and Van Waerebeek (2011) have suggested a cause-effect 
relationship between a seismic survey off Liberia in 2009 and the 
erratic movement, postural instability, and akinesia in a pantropical 
spotted dolphin based on spatially and temporally close association 
with the airgun array. Additionally, 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 
(Castellote and Llorens, 2013).
    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

[[Page 15077]]

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--The proposed 
action is not a military readiness activity or using military active 
sonar (non-pulse). Several sources have published lists of mass 
stranding events of cetaceans in an attempt to identify relationships 
between those stranding events and military active sonar (Hildebrand, 
2004; IWC, 2005; Taylor et al., 2004). For example, based on a review 
of stranding records between 1960 and 1995, the International Whaling 
Commission (2005) identified ten mass stranding events and concluded 
that, out of eight stranding events reported from the mid-1980s to the 
summer of 2003, seven had been coincident with the use of mid-frequency 
active sonar and most involved beaked whales.
    Over the past 12 years, there have been five stranding events 
coincident with military mid-frequency active sonar use in which 
exposure to sonar is believed to have been a contributing factor to 
strandings: Greece (1996); the Bahamas (2000); Madeira (2000); Canary 
Islands (2002); and Spain (2006). Refer to Cox et al. (2006) for a 
summary of common features shared by the strandings events in Greece 
(1996), Bahamas (2000), Madeira (2000), and Canary Islands (2002); and 
Fernandez et al., (2005) for an additional summary of the Canary 
Islands 2002 stranding event.
    Potential for Stranding From Seismic Surveys--Marine mammals close 
to underwater detonations of high explosives can be killed or severely 
injured, and the auditory organs are especially susceptible to injury 
(Ketten et al., 1993; Ketten, 1995). However, explosives are no longer 
used in marine waters for commercial seismic surveys or (with rare 
exceptions) for seismic research. These methods have been replaced 
entirely by airguns or related non-explosive pulse generators. Airgun 
pulses are less energetic and have slower rise times, and there is no 
specific evidence that they can cause serious injury, death, or 
stranding even in the case of large airgun arrays. However, the 
association of strandings of beaked whales with naval exercises 
involving mid-frequency active sonar (non-pulse sound) and, in one 
case, the regional co-occurrence of an L-DEO seismic survey (Malakoff, 
2002; Cox et al., 2006), has raised the possibility that beaked whales 
exposed to strong ``pulsed'' sounds could also be susceptible to injury 
and/or behavioral reactions that can lead to stranding (e.g., 
Hildebrand, 2005; Southall et al., 2007).
    Specific sound-related processes that lead to strandings and 
mortality are not well documented, but may include:
    (1) Swimming in avoidance of a sound into shallow water;
    (2) A change in behavior (such as a change in diving behavior) that 
might contribute to tissue damage, gas bubble formation, hypoxia, 
cardiac arrhythmia, hypertensive hemorrhage or other forms of trauma;
    (3) A physiological change such as a vestibular response leading to 
a behavioral change or stress-induced hemorrhagic diathesis, leading in 
turn to tissue damage; and
    (4) Tissue damage directly from sound exposure, such as through 
acoustically-mediated bubble formation and growth or acoustic resonance 
of tissues.
    Some of these mechanisms are unlikely to apply in the case of 
impulse sounds. However, there are indications that gas-bubble disease 
(analogous to ``the bends''), induced in supersaturated tissue by a 
behavioral response to acoustic exposure, could be a pathologic 
mechanism for the strandings and mortality of some deep-diving 
cetaceans exposed to sonar. The evidence for this remains 
circumstantial and associated with exposure to naval mid-frequency 
sonar, not seismic surveys (Cox et al., 2006; Southall et al., 2007).
    Seismic pulses and mid-frequency sonar signals are quite different, 
and some mechanisms by which sonar sounds have been hypothesized to 
affect beaked whales are unlikely to apply to airgun pulses. Sounds 
produced by airgun arrays are broadband impulses with most of the 
energy below one kHz. Typical military mid-frequency sonar emits non-
impulse sounds at frequencies of 2 to 10 kHz, generally with a 
relatively narrow bandwidth at any one time. A further difference 
between seismic surveys and naval exercises is that naval exercises can 
involve sound sources on more than one vessel. Thus, it is not 
appropriate to expect that the same effects to marine mammals would 
result from military sonar and seismic surveys. However, evidence that 
sonar signals can, in special circumstances, lead (at least indirectly) 
to physical damage and mortality (e.g., Balcomb and Claridge, 2001; 
NOAA and USN, 2001; Jepson et al., 2003; Fern[aacute]ndez et al., 2004, 
2005; Hildebrand 2005; Cox et al., 2006) suggests that caution is 
warranted when dealing with exposure of marine mammals to any high-
intensity sound.
    There is no conclusive evidence of cetacean strandings or deaths at 
sea as a result of exposure to seismic surveys, but a few cases of 
strandings in the general area where a seismic survey was ongoing have 
led to speculation concerning a possible link between seismic surveys 
and strandings. Suggestions that there was a link between seismic 
surveys and strandings of humpback whales in Brazil (Engel et al., 
2004) were not well founded (IAGC, 2004; IWC, 2007). In September 2002, 
there was a stranding of two Cuvier's beaked whales in the Gulf of 
California, Mexico, when the L-DEO vessel R/V Maurice Ewing was 
operating a 20 airgun (8,490 in\3\) array in the general region. The 
link between the stranding and the seismic surveys was inconclusive and 
not based on any physical evidence (Hogarth, 2002; Yoder, 2002). 
Nonetheless, the Gulf of California incident plus the beaked whale 
strandings near naval exercises involving use of mid-frequency sonar 
suggests a need for caution in conducting seismic surveys in areas 
occupied by beaked whales until more is known about effects of seismic 
surveys on those species (Hildebrand, 2005). No injuries of beaked 
whales are anticipated during the proposed study because of:
    (1) The high likelihood that any beaked whales nearby would avoid 
the approaching vessel before being exposed to high sound levels, and
    (2) Differences between the sound sources to be used in the 
proposed study and operated by SIO and those involved in the naval 
exercises associated with strandings.

Potential Effects of Other Acoustic Devices and Sources

Multi-Beam Echosounder
    SIO would operate the Kongsberg EM 122 multi-beam echosounder from 
the source vessel during the planned study. Sounds from the multi-beam 
echosounder are very short pulses, occurring for approximately 2 to 15 
ms once every 5 to 20 seconds, depending on water depth. Most of the 
energy in the sound pulses emitted by the multi-beam echosounder is at 
frequencies near 12 kHz (10.5 to 13), and the maximum source level is 
242 dB re 1 [mu]Pa (rms). The beam is narrow (1 to 2[deg]) in fore-aft 
extent and wide (150[deg]) in the cross-track extent. Each ping 
consists of eight (in water greater than 1,000 m deep) or four (in 
water less than 1,000 m) consecutive successive fan-shaped 
transmissions (segments) at different cross-track angles. Any given 
marine mammal at depth near the trackline would be in the

[[Page 15078]]

main beam for only one or two of the eight 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 would receive only limited amounts of pulse energy because 
of the short pulses. Animals close to the ship (where the beam is 
narrowest) are especially unlikely to be ensonified for more than one 2 
to 15 ms pulse (or two pulses if in the overlap area). Similarly, 
Kremser et al. (2005) noted that the probability of a cetacean swimming 
through the area of exposure when a multi-beam echosounder emits a 
pulse is small. The animal would have to pass the transducer at close 
range and be swimming at speeds similar to the vessel in order to 
receive the multiple pulses that might result in sufficient exposure to 
cause TTS.
    Navy sonars that have been linked to avoidance reactions and 
stranding of cetaceans: (1) Generally have longer pulse duration than 
the Kongsberg EM 122; and (2) are often directed close to horizontally, 
as well as omnidirectional, versus more downward and narrowly for the 
multi-beam echosounder. The area of possible influence of the multi-
beam echosounder is much smaller--a narrow band below the source 
vessel. Also, the duration of exposure for a given marine mammal can be 
much longer for naval sonar. During SIO's operations, the individual 
pulses would be very short, and a given mammal would not receive many 
of the downward-directed pulses as the vessel passes by. Possible 
effects of a multi-beam echosounder on marine mammals are described 
below.
    Stranding--In 2013, an International Scientific Review Panel 
investigated a 2008 mass stranding of approximately 100 melon-headed 
whales in a Madagascar lagoon system (Southall et al., 2013) associated 
with the use of a high-frequency mapping system. The report indicated 
that the use of a 12 kHz multi-beam echosounder was the most plausible 
and likely initial behavioral trigger of the mass stranding event. This 
was the first time that a relatively high-frequency mapping sonar 
system has been associated with a stranding event. However, the report 
also notes that there were several site- and situation-specific 
secondary factors that may have contributed to the avoidance responses 
that lead to the eventual entrapment and mortality of the whales within 
the Loza Lagoon system (e.g., the survey vessel transiting in a north-
south direction on the shelf break parallel to the shore may have 
trapped the animals between the sound source and the shore driving them 
towards the Loza Lagoon). The report concluded that for odontocete 
cetaceans that hear well in the 10 to 50 kHz range, where ambient noise 
is typically quite low, high-power active sonars operating in this 
range may be more easily audible and have potential effects over larger 
areas than low-frequency systems that have more typically been 
considered in terms of anthropogenic noise impacts (Southall et al., 
2013). However, the risk may be very low given the extensive use of 
these systems worldwide on a daily basis and the lack of direct 
evidence of such responses previously (Southall et al., 2013). It is 
noted that leading scientific experts on multi-beam echosounders have 
expressed concerns about the independent scientific review panel 
analyses and findings (Bernstein, 2013).
    Masking--Marine mammal communications would not be masked 
appreciably by the multi-beam echosounder signals, given the low duty 
cycle of the echosounder and the brief period when an individual mammal 
is likely to be within its beam. Furthermore, in the case of baleen 
whales, the multi-beam echosounder signals (12 kHz) generally do not 
overlap with the predominant frequencies in the calls (16 Hz to less 
than 12 kHz), which would avoid any significant masking (Richardson et 
al., 1995).
    Behavioral Responses--Behavioral reactions of free-ranging marine 
mammals to sonars, echosounders, and other sound sources appear to vary 
by species and circumstance. Observed reactions have included silencing 
and dispersal by sperm whales (Watkins et al., 1985), increased 
vocalizations and no dispersal by pilot whales (Rendell and Gordon, 
1999), and the previously-mentioned beachings by beaked whales. During 
exposure to a 21 to 25 kHz ``whale-finding'' sonar with a source level 
of 215 dB re 1 [mu]Pa, gray whales reacted by orienting slightly away 
from the source and being deflected from their course by approximately 
200 m (656.2 ft) (Frankel, 2005). When a 38 kHz echosounder and a 150 
kHz ADCP were transmitting during studies in the Eastern Tropical 
Pacific, baleen whales showed no significant responses, while spotted 
and spinner dolphins were detected slightly more often and beaked 
whales less often during visual surveys (Gerrodette and Pettis, 2005).
    Captive bottlenose dolphins and a beluga whale exhibited changes in 
behavior when exposed to 1 second tonal signals at frequencies similar 
to those that would be emitted by the multi-beam echosounder used by 
SIO, and to shorter broadband pulsed signals. Behavioral changes 
typically involved what appeared to be deliberate attempts to avoid the 
sound exposure (Schlundt et al., 2000; Finneran et al., 2002; Finneran 
and Schlundt, 2004). The relevance of those data to free-ranging 
odontocetes is uncertain, and in any case, the test sounds were quite 
different in duration as compared with those from a multi-beam 
echosounder.
    Risch et al. (2012) found a reduction in humpback whale song in the 
Stellwagen Bank National Marine Sanctuary during Ocean Acoustic 
Waveguide Remote Sensing (OAWRS) activities that were carried out 
approximately 200 km (108 nmi) away. The OAWRS used three frequency-
modulated pulses centered at frequencies of 415, 734, and 949 Hz with 
received levels in the sanctuary of 88 to 110 dB re 1 [mu]Pa. Deng et 
al. (2014) measured the spectral properties of pulses transmitted by 
three 200 kHz echosounders, and found that they generated weaker sounds 
at frequencies below the center frequency (90 to 130 kHz). These sounds 
are within the hearing range of some marine mammals, and the authors 
suggested that they could be strong enough to elicit behavioral 
responses within close proximity to the sources, although they would be 
well below potentially harmful levels.
    Hearing Impairment and Other Physical Effects--Given several 
stranding events that have been associated with the operation of naval 
sonar in specific circumstances, there is concern that mid-frequency 
sonar sounds can cause serious impacts to marine mammals (see above). 
However, the multi-beam echosounder proposed for use by SIO is quite 
different than sonar used for Navy operations. Pulse duration of the 
multi-beam echosounder is very short relative to the naval sonar. Also, 
at any given location, an individual marine mammal would be in the beam 
of the multi-beam echosounder for much less time, given the generally 
downward orientation of the beam and its narrow fore-aft beamwidth; 
Navy sonar often uses near-horizontally-directed sound and have higher 
duty cycles. Those factors would all reduce the sound energy received 
from the multi-beam echosounder rather drastically relative to that 
from naval sonar. NMFS believes that the brief exposure of marine 
mammals to one pulse, or small numbers of signals, from the multi-beam 
echosounder in this particular case is not likely to result in the 
harassment of marine mammals.

[[Page 15079]]

Sub-Bottom Profiler

    SIO would operate a sub-bottom profiler (Knudsen 3260) from the 
source vessel during the proposed study. Sounds from the sub-bottom 
profiler are very short pulses, occurring for 1 to 4 ms once ever 
second. Most of the energy in the sound pulses emitted by the sub-
bottom profiler is at frequencies 3.5 kHz, and the beam is directed 
downward. The sub-bottom profiler that may be used on the Revelle has a 
maximum source level of 204 dB re 1 [mu]Pa. The sonar emits energy in a 
27[deg] beam from the bottom of the ship. Marine mammals that encounter 
the Knudsen 3260 are unlikely to be subjected to repeated pulses 
because of the relatively narrow fore-aft width of the beam and would 
receive only limited amounts of pulse energy because of the short 
pulses. Animals close to the ship (where the beam is narrowest) are 
especially unlikely to be ensonified for more than one pulse (or two 
pulses if in the overlap area). Similarly, Kremser et al. (2005) noted 
that the probability of a cetacean swimming through the area of 
exposure when a sub-bottom profiler emits a pulse is small--even for a 
sub-bottom profiler more powerful than that that may be on the Revelle. 
The animal would have to pass the transducer at close range and be 
swimming at speeds similar to the vessel in order to receive the 
multiple pulses that might result in sufficient exposure to cause TTS.
    Navy sonars that have been linked to avoidance reactions and 
stranding of cetaceans: (1) Generally have longer pulse duration than 
the Knudsen 3260; and (2) are often directed close to horizontally 
versus more downward for the sub-bottom profiler. The area of possible 
influence of the single-beam echosounder is much smaller--a narrow band 
below the source vessel. Also, the duration of exposure for a given 
marine mammal can be much longer for naval sonar. During SIO's 
operations, the individual pulses would be very short, and a given 
mammal would not receive many of the downward-directed pulses as the 
vessel passes by. Possible effects of a sub-bottom profiler on marine 
mammals are described below.
    Masking--Marine mammal communications would not be masked 
appreciably by the sub-bottom profiler signals given the directionality 
of the signal and the brief period when an individual mammal is likely 
to be within its beam. Furthermore, in the case of baleen whales, the 
sub-bottom profiler signals do not overlap with the predominant 
frequencies in the calls (16 Hz to less than 12 kHz), which would avoid 
any significant masking (Richardson et al., 1995).
    Behavioral Responses--Marine mammal behavioral reactions to other 
pulsed sound sources are discussed above, and responses to the sub-
bottom profiler are likely to be similar to those for other pulsed 
sources if received at the same levels. However, the pulsed signals 
from the sub-bottom profiler are considerably weaker than those from 
the multi-beam echosounder. Therefore, behavioral responses are not 
expected unless marine mammals are very close to the source.
    Hearing Impairment and Other Physical Effects--It is unlikely that 
the sub-bottom profiler produces pulse levels strong enough to cause 
hearing impairment or other physical injuries even in an animal that is 
(briefly) in a position near the source. The sub-bottom profiler is 
usually operated simultaneously with other higher-power acoustic 
sources, including airguns. Many marine mammals will move away in 
response to the approaching higher-power sources or the vessel itself 
before the mammals would be close enough for there to be any 
possibility of effects from the less intense sounds from the sub-bottom 
profiler.

Heat-Flow Probe Deployment

    During heat-flow measurements using a probe, the probe is a passive 
instrument and no noise is created by the mechanical action of the 
devices on the seafloor is not expected to be perceived by nearby fish 
and other marine organisms. Heat-flow measurement activities would be 
highly localized and short-term in duration and would not be expected 
to significantly interfere with marine mammal behavior. The potential 
direct effects include temporary localized disturbance or displacement 
from associated physical movement/actions of the operations. 
Additionally, the potential indirect effects may consist of very 
localized and transitory/short-term disturbance of bottom habitat and 
associated prey in shallow-water areas as a result of heat-flow probe 
measurements. NMFS believes that the since the heat-flow probe is a 
passive instrument and has no mechanical action, it would not likely 
result in the harassment of marine mammals.
    A maximum total of 200 heat-flow measurements would be obtained 
using these devices and ranging from 1 to 2 hours per measurement (for 
a total of approximately 320 hours of operations) and it is estimated 
that the pinger would operate continuously during each heat-flow probe 
deployment. The vessel would be stationary during heat-flow probe 
deployment and repositioned to repeat the process, so the likelihood of 
a collision or entanglement with a marine mammal is very low. For the 
heat-flow measurements, the lance is 4.5 m and would disturb an area 
approximately 8 cm x 20 cm (3.1 in x 7.9 in). Assuming approximately 
200 heat-flow measurements, the cumulative area of seafloor that could 
be disturbed during the proposed study would be approximately 32,000 
cm\2\ (4,960 in\2\).

Vessel Movement and Collisions

    Vessel movement in the vicinity of marine mammals has the potential 
to result in either a behavioral response or a direct physical 
interaction. Both scenarios are discussed below in this section.
    Behavioral Responses to Vessel Movement--There are limited data 
concerning marine mammal behavioral responses to vessel traffic and 
vessel noise, and a lack of consensus among scientists with respect to 
what these responses mean or whether they result in short-term or long-
term adverse effects. In those cases where there is a busy shipping 
lane or where there is a large amount of vessel traffic, marine mammals 
(especially low frequency specialists) may experience acoustic masking 
(Hildebrand, 2005) if they are present in the area (e.g., killer whales 
in Puget Sound; Foote et al., 2004; Holt et al., 2008). In cases where 
vessels actively approach marine mammals (e.g., whale watching or 
dolphin watching boats), scientists have documented that animals 
exhibit altered behavior such as increased swimming speed, erratic 
movement, and active avoidance behavior (Bursk, 1983; Acevedo, 1991; 
Baker and MacGibbon, 1991; Trites and Bain, 2000; Williams et al., 
2002; Constantine et al., 2003), reduced blow interval (Ritcher et al., 
2003), disruption of normal social behaviors (Lusseau, 2003, 2006), and 
the shift of behavioral activities which may increase energetic costs 
(Constantine et al., 2003, 2004). A detailed review of marine mammal 
reactions to ships and boats is available in Richardson et al., (1995). 
For each of the marine mammal taxonomy groups, Richardson et al., 
(1995) provides the following assessment regarding reactions to vessel 
traffic:
    Toothed whales--``In summary, toothed whales sometimes show no 
avoidance reaction to vessels, or even approach them. However, 
avoidance can occur, especially in response to vessels of types used to 
chase or hunt the animals. This may cause temporary displacement, but 
we know of no clear evidence that toothed whales have

[[Page 15080]]

abandoned significant parts of their range because of vessel traffic.''
    Baleen whales--``When baleen whales receive low-level sounds from 
distant or stationary vessels, the sounds often seem to be ignored. 
Some whales approach the sources of these sounds. When vessels approach 
whales slowly and non-aggressively, whales often exhibit slow and 
inconspicuous avoidance maneuvers. In response to strong or rapidly 
changing vessel noise, baleen whales often interrupt their normal 
behavior and swim rapidly away. Avoidance is especially strong when a 
boat heads directly toward the whale.''
    Behavioral responses to stimuli are complex and influenced to 
varying degrees by a number of factors, such as species, behavioral 
contexts, geographical regions, source characteristics (moving or 
stationary, speed, direction, etc.), prior experience of the animal and 
physical status of the animal. For example, studies have shown that 
beluga whales' reaction varied when exposed to vessel noise and 
traffic. In some cases, beluga whales exhibited rapid swimming from 
ice-breaking vessels up to 80 km (43.2 nmi) away and showed changes in 
surfacing, breathing, diving, and group composition in the Canadian 
high Arctic where vessel traffic is rare (Finley et al., 1990). In 
other cases, beluga whales were more tolerant of vessels, but responded 
differentially to certain vessels and operating characteristics by 
reducing their calling rates (especially older animals) in the St. 
Lawrence River where vessel traffic is common (Blane and Jaakson, 
1994). In Bristol Bay, Alaska, beluga whales continued to feed when 
surrounded by fishing vessels and resisted dispersal even when 
purposefully harassed (Fish and Vania, 1971).
    In reviewing more than 25 years of whale observation data, Watkins 
(1986) concluded that whale reactions to vessel traffic were ``modified 
by their previous experience and current activity: Habituation often 
occurred rapidly, attention to other stimuli or preoccupation with 
other activities sometimes overcame their interest or wariness of 
stimuli.'' Watkins noticed that over the years of exposure to ships in 
the Cape Cod area, minke whales changed from frequent positive interest 
(e.g., approaching vessels) to generally uninterested reactions; fin 
whales changed from mostly negative (e.g., avoidance) to uninterested 
reactions; fin whales changed from mostly negative (e.g., avoidance) to 
uninterested reactions; right whales apparently continued the same 
variety of responses (negative, uninterested, and positive responses) 
with little change; and humpbacks dramatically changed from mixed 
responses that were often negative to reactions that were often 
strongly positive. Watkins (1986) summarized that ``whales near shore, 
even in regions with low vessel traffic, generally have become less 
wary of boats and their noises, and they have appeared to be less 
easily disturbed than previously. In particular locations with intense 
shipping and repeated approaches by boats (such as the whale-watching 
areas of Stellwagen Bank), more and more whales had positive reactions 
to familiar vessels, and they also occasionally approached other boats 
and yachts in the same ways.''
    Although the radiated sound from the Revelle would be audible to 
marine mammals over a large distance, it is unlikely that marine 
mammals would respond behaviorally (in a manner that NMFS would 
consider harassment under the MMPA) to low-level distant shipping noise 
as the animals in the area are likely to be habituated to such noises 
(Nowacek et al., 2004). In light of these facts, NMFS does not expect 
the Revelle's movements to result in Level B harassment.
    Vessel Strike--Ship strikes of cetaceans can cause major wounds, 
which may lead to the death of the animal. An animal at the surface 
could be struck directly by a vessel, a surfacing animal could hit the 
bottom of a vessel, or an animal just below the surface could be cut by 
a vessel's propeller. The severity of injuries typically depends on the 
size and speed of the vessel (Knowlton and Kraus, 2001; Laist et al., 
2001; Vanderlaan and Taggart, 2007).
    The most vulnerable marine mammals are those that spend extended 
periods of time at the surface in order to restore oxygen levels within 
their tissues after deep dives (e.g., the sperm whale). In addition, 
some baleen whales, such as the North Atlantic right whale, seem 
generally unresponsive to vessel sound, making them more susceptible to 
vessel collisions (Nowacek et al., 2004). These species are primarily 
large, slow moving whales. Smaller marine mammals (e.g., bottlenose 
dolphins) move quickly through the water column and are often seen 
riding the bow wave of large ships. Marine mammal responses to vessels 
may include avoidance and changes in dive pattern (NRC, 2003).
    An examination of all known ship strikes from all shipping sources 
(civilian and military) indicates vessel speed is a principal factor in 
whether a vessel strike results in death (Knowlton and Kraus, 2001; 
Laist et al., 2001; Jensen and Silber, 2003; Vanderlaan and Taggart, 
2007). In assessing records in which vessel speed was known, Laist et 
al. (2001) found a direct relationship between the occurrence of a 
whale strike and the speed of the vessel involved in the collision. The 
authors concluded that most deaths occurred when a vessel was traveling 
in excess of 13 kts (24.1 km/hr, 14.9 mph).
    SIO's proposed operation of one source vessel for the proposed low-
energy seismic survey is relatively small in scale (i.e., a one vessel 
operation) compared to the number of other ships (e.g., fishing, 
tourist, and other vessels) transiting at higher speeds in the same 
areas on an annual basis. The probability of vessel and marine mammal 
interactions occurring during the proposed low-energy seismic survey is 
unlikely due to the Revelle's slow operational speed, which is 
typically 5 kts. Outside of seismic operations, the Revelle's cruising 
speed would be approximately 10.1 to 14.5 kts, which is generally below 
the speed at which studies have noted reported increases of marine 
mammal injury or death (Laist et al., 2001).
    As a final point, the Revelle has a number of other advantages for 
avoiding ship strikes as compared to most commercial merchant vessels, 
including the following: The Revelle's bridge and other observing 
stations offer good visibility to visually monitor for marine mammal 
presence; PSOs posted during operations scan the ocean for marine 
mammals and must report visual alerts of marine mammal presence to 
crew; and the PSOs receive extensive training that covers the 
fundamentals of visual observing for marine mammals and information 
about marine mammals and their identification at sea.

Entanglement

    Entanglement can occur if wildlife becomes immobilized in survey 
lines, cables, nets, or other equipment that is moving through the 
water column. The proposed low-energy seismic survey would require 
towing approximately one 600 m cable streamers. While towing this size 
of an array carries some level of risk of entanglement for marine 
mammals due to the operational nature of the activity, entanglement is 
unlikely. Wildlife, especially slow moving individuals, such as large 
whales, have a low probability of becoming entangled due to slow speed 
of the survey vessel and onboard monitoring efforts. In May 2011, there 
was one recorded entrapment of an olive ridley sea turtle (Lepidochelys 
olivacea) in the R/V Marcus G. Langseth's barovanes after the 
conclusion of a seismic survey off

[[Page 15081]]

Costa Rica. There have been cases of baleen whales, mostly gray whales 
(Heyning, 1990), becoming entangled in fishing lines. The probability 
for entanglement of marine mammals is considered very low because of 
the vessel speed and the monitoring efforts onboard the survey vessel. 
Furthermore, there has been no history of marine mammal entanglement 
with seismic equipment used by the U.S. academic research fleet.
    The potential effects to marine mammals described in this section 
of the document do not take into consideration the proposed monitoring 
and mitigation measures described later in this document (see the 
``Proposed Mitigation'' and ``Proposed Monitoring and Reporting'' 
sections) which, as noted are designed to effect the least practicable 
impact on affected marine mammal species and stocks.

Anticipated Effects on Marine Mammal Habitat

    The proposed low-energy seismic survey is not anticipated to have 
any permanent impact on habitats used by the marine mammals in the 
proposed study 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 airgun operations during the 
proposed low-energy seismic survey. While it is anticipated that the 
specified activity may result in marine mammals avoiding certain areas 
due to brief, temporary ensonification, this impact to habitat is 
temporary and was considered in further detail earlier in this 
document, as behavioral modification. The main impact associated with 
the proposed activity would be temporarily elevated noise levels and 
the associated direct effects on marine mammals in any particular area 
of the approximately 1,154 km \2\ proposed study area, previously 
discussed in this notice.
    The next section discusses the potential impacts of anthropogenic 
sound sources on common marine mammal prey in the proposed study area 
(i.e., fish and invertebrates).

Anticipated Effects on Fish

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

[[Page 15082]]

(2004), for the types of seismic airguns and arrays involved with the 
proposed program, the pathological (mortality) zone for fish would be 
expected to be within a few meters of the seismic source. Numerous 
other studies provide examples of no fish mortality upon exposure to 
seismic sources (Falk and Lawrence, 1973; Holliday et al., 1987; La 
Bella et al., 1996; Santulli et al., 1999; McCauley et al., 2000a,b, 
2003; Bjarti, 2002; Thomsen, 2002; Hassel et al., 2003; Popper et al., 
2005; Boeger et al., 2006).
    An experiment of the effects of a single 700 in \3\ airgun was 
conducted in Lake Meade, Nevada (USGS, 1999). The data were used in an 
Environmental Assessment of the effects of a marine reflection survey 
of the Lake Meade fault system by the National Park Service (Paulson et 
al., 1993, in USGS, 1999). The airgun was suspended 3.5 m (11.5 ft) 
above a school of threadfin shad in Lake Meade and was fired three 
successive times at a 30 second interval. Neither surface inspection 
nor diver observations of the water column and bottom found any dead 
fish.
    For a proposed seismic survey in Southern California, USGS (1999) 
conducted a review of the literature on the effects of airguns on fish 
and fisheries. They reported a 1991 study of the Bay Area Fault system 
from the continental shelf to the Sacramento River, using a 10 airgun 
(5,828 in\3\) array. Brezzina and Associates were hired by USGS to 
monitor the effects of the surveys and concluded that airgun operations 
were not responsible for the death of any of the fish carcasses 
observed. They also concluded that the airgun profiling did not appear 
to alter the feeding behavior of sea lions, seals, or pelicans observed 
feeding during the seismic surveys.
    Some studies have reported, some equivocally, that mortality of 
fish, fish eggs, or larvae can occur close to seismic sources 
(Kostyuchenko, 1973; Dalen and Knutsen, 1986; Booman et al., 1996; 
Dalen et al., 1996). Some of the reports claimed seismic effects from 
treatments quite different from actual seismic survey sounds or even 
reasonable surrogates. However, Payne et al. (2009) reported no 
statistical differences in mortality/morbidity between control and 
exposed groups of capelin eggs or monkfish larvae. Saetre and Ona 
(1996) applied a `worst-case scenario' mathematical model to 
investigate the effects of seismic energy on fish eggs and larvae. They 
concluded that mortality rates caused by exposure to seismic surveys 
are so low, as compared to natural mortality rates, that the impact of 
seismic surveying on recruitment to a fish stock must be regarded as 
insignificant.
    Physiological Effects--Physiological effects refer to cellular and/
or biochemical responses of fish to acoustic stress. Such stress 
potentially could affect fish populations by increasing mortality or 
reducing reproductive success. Primary and secondary stress responses 
of fish after exposure to seismic survey sound appear to be temporary 
in all studies done to date (Sverdrup et al., 1994; Santulli et al., 
1999; McCauley et al., 2000a,b). The periods necessary for the 
biochemical changes to return to normal are variable and depend on 
numerous aspects of the biology of the species and of the sound 
stimulus.
    Behavioral Effects--Behavioral effects include changes in the 
distribution, migration, mating, and catchability of fish populations. 
Studies investigating the possible effects of sound (including seismic 
survey sound) on fish behavior have been conducted on both uncaged and 
caged individuals (e.g., Chapman and Hawkins, 1969; Pearson et al., 
1992; Santulli et al., 1999; Wardle et al., 2001; Hassel et al., 2003). 
Typically, in these studies fish exhibited a sharp startle response at 
the onset of a sound followed by habituation and a return to normal 
behavior after the sound ceased.
    The former Minerals Management Service (MMS, 2005) assessed the 
effects of a proposed seismic survey in Cook Inlet. The seismic survey 
proposed using three vessels, each towing two four-airgun arrays 
ranging from 24,580.6 to 40,967.7 cm\3\ (1,500 to 2,500 in\3\). MMS 
noted that the impact to fish populations in the survey area and 
adjacent waters would likely be very low and temporary. MMS also 
concluded that seismic surveys may displace the pelagic fishes from the 
area temporarily when airguns are in use. However, fishes displaced and 
avoiding the airgun noise are likely to backfill the survey area in 
minutes to hours after cessation of seismic testing. Fishes not 
dispersing from the airgun noise (e.g., demersal species) may startle 
and move short distances to avoid airgun emissions.
    In general, any adverse effects on fish behavior or fisheries 
attributable to seismic testing may depend on the species in question 
and the nature of the fishery (season, duration, fishing method). They 
may also depend on the age of the fish, its motivational state, its 
size, and numerous other factors that are difficult, if not impossible, 
to quantify at this point, given such limited data on effects of 
airguns on fish, particularly under realistic at-sea conditions.

Anticipated Effects on Invertebrates

    The existing body of information on the impacts of seismic survey 
sound on marine invertebrates is very limited. However, there is some 
unpublished and very limited evidence of the potential for adverse 
effects on invertebrates, thereby justifying further discussion and 
analysis of this issue. The three types of potential effects of 
exposure to seismic surveys on marine invertebrates are pathological, 
physiological, and behavioral. Based on the physical structure of their 
sensory organs, marine invertebrates appear to be specialized to 
respond to particle displacement components of an impinging sound field 
and not to the pressure component (Popper et al., 2001).
    The only information available on the impacts of seismic surveys on 
marine invertebrates involves studies of individuals; there have been 
no studies at the population scale. Thus, available information 
provides limited insight on possible real-world effects at the regional 
or ocean scale. The most important aspect of potential impacts concerns 
how exposure to seismic survey sound ultimately affects invertebrate 
populations and their viability, including availability to fisheries.
    Literature reviews of the effects of seismic and other underwater 
sound on invertebrates were provided by Moriyasu et al. (2004) and 
Payne et al. (2008). The following sections provide a synopsis of 
available information on the effects of exposure to seismic survey 
sound on species of decapod crustaceans and cephalopods, the two 
taxonomic groups of invertebrates on which most such studies have been 
conducted. The available information is from studies with variable 
degrees of scientific soundness and from anecdotal information. A more 
detailed review of the literature on the effects of seismic survey 
sound on invertebrates is provided in Appendix D of NSF/USGS's PEIS 
(2011).
    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

[[Page 15083]]

expected to be within a few meters of the seismic source, at most; 
however, very few specific data are available on levels of seismic 
signals that might damage these animals. This premise is based on the 
peak pressure and rise/decay time characteristics of seismic airgun 
arrays currently in use around the world.
    Some studies have suggested that seismic survey sound has a limited 
pathological impact on early developmental stages of crustaceans 
(Pearson et al., 1994; Christian et al., 2003; DFO, 2004). However, the 
impacts appear to be either temporary or insignificant compared to what 
occurs under natural conditions. Controlled field experiments on adult 
crustaceans (Christian et al., 2003, 2004; DFO, 2004) and adult 
cephalopods (McCauley et al., 2000a,b) exposed to seismic survey sound 
have not resulted in any significant pathological impacts on the 
animals. It has been suggested that exposure to commercial seismic 
survey activities has injured giant squid (Guerra et al., 2004), but 
the article provides little evidence to support this claim. Tenera 
Environmental (2011b) reported that Norris and Mohl (1983, summarized 
in Mariyasu et al., 2004) observed lethal effects in squid (Loligo 
vulgaris) at levels of 246 to 252 dB after 3 to 11 minutes.
    Andre et al. (2011) exposed four species of cephalopods (Loligo 
vulgaris, Sepia officinalis, Octopus vulgaris, and Ilex coindetii), 
primarily cuttlefish, to two hours of continuous 50 to 400 Hz 
sinusoidal wave sweeps at 157+/-5 dB re 1 [micro]Pa while captive in 
relatively small tanks. They reported morphological and ultrastructural 
evidence of massive acoustic trauma (i.e., permanent and substantial 
alterations [lesions] of statocyst sensory hair cells) to the exposed 
animals that increased in severity with time, suggesting that 
cephalopods are particularly sensitive to low frequency sound. The 
received SPL was reported as 157+/-5 dB re 1 [micro]Pa, with peak 
levels at 175 dB re 1 [micro]Pa. As in the McCauley et al. (2003) paper 
on sensory hair cell damage in pink snapper as a result of exposure to 
seismic sound, the cephalopods were subjected to higher sound levels 
than they would be under natural conditions, and they were unable to 
swim away from the sound source.
    Physiological Effects--Physiological effects refer mainly to 
biochemical responses by marine invertebrates to acoustic stress. Such 
stress potentially could affect invertebrate populations by increasing 
mortality or reducing reproductive success. Primary and secondary 
stress responses (i.e., changes in haemolymph levels of enzymes, 
proteins, etc.) of crustaceans have been noted several days or months 
after exposure to seismic survey sounds (Payne et al., 2007). It was 
noted however, that no behavioral impacts were exhibited by crustaceans 
(Christian et al., 2003, 2004; DFO, 2004). The periods necessary for 
these biochemical changes to return to normal are variable and depend 
on numerous aspects of the biology of the species and of the sound 
stimulus.
    Behavioral Effects--There is increasing interest in assessing the 
possible direct and indirect effects of seismic and other sounds on 
invertebrate behavior, particularly in relation to the consequences for 
fisheries. Changes in behavior could potentially affect such aspects as 
reproductive success, distribution, susceptibility to predation, and 
catchability by fisheries. Studies investigating the possible 
behavioral effects of exposure to seismic survey sound on crustaceans 
and cephalopods have been conducted on both uncaged and caged animals. 
In some cases, invertebrates exhibited startle responses (e.g., squid 
in McCauley et al., 2000a,b). In other cases, no behavioral impacts 
were noted (e.g., crustaceans in Christian et al., 2003, 2004; DFO 
2004). There have been anecdotal reports of reduced catch rates of 
shrimp shortly after exposure to seismic surveys; however, other 
studies have not observed any significant changes in shrimp catch rate 
(Andriguetto-Filho et al., 2005). Similarly, Parry and Gason (2006) did 
not find any evidence that lobster catch rates were affected by seismic 
surveys. Any adverse effects on crustacean and cephalopod behavior or 
fisheries attributable to seismic survey sound depend on the species in 
question and the nature of the fishery (season, duration, fishing 
method). More information on the potential effects of airguns on fish 
and invertebrates are reviewed in section 3.2.4.3, section 3.3.4.3, and 
Appendix D of the NSF/USGS PEIS (2011).

Proposed Mitigation

    In order to issue an Incidental Take Authorization (ITA) under 
section 101(a)(5)(D) of the MMPA, NMFS must set forth the permissible 
methods of taking pursuant to such activity, and other means of 
effecting the least practicable impact on such species or stock and its 
habitat, paying particular attention to rookeries, mating grounds, and 
areas of similar significance, and the availability of such species or 
stock for taking for certain subsistence uses (where relevant).
    SIO reviewed the following source documents and incorporated a 
suite of appropriate mitigation measures into the project description.
    (1) Protocols used during previous NSF and USGS-funded seismic 
research cruises as approved by NMFS and detailed in the ``Final 
Programmatic Environmental Impact Statement/Overseas Environmental 
Impact Statement for Marine Seismic Research Funded by the National 
Science Foundation or Conducted by the U.S. Geological Survey;''
    (2) Previous IHA applications and IHAs approved and authorized by 
NMFS; and
    (3) Recommended best practices in Richardson et al. (1995), Pierson 
et al. (1998), and Weir and Dolman, (2007).
    To reduce the potential for disturbance from acoustic stimuli 
associated with the activities, SIO proposed to implement the following 
mitigation measures for marine mammals:
    (1) Proposed exclusion zones around the sound source;
    (2) Speed and course alterations;
    (3) Shut-down procedures; and
    (4) Ramp-up procedures.
    Proposed Exclusion Zones--During pre-planning of the cruise, the 
smallest airgun array was identified that could be used and still meet 
the geophysical scientific objectives. SIO use radii to designate 
exclusion and buffer zones and to estimate take for marine mammals. 
Table 2 (presented earlier in this document) shows the distances at 
which one would expect to receive three sound levels (160, 180, and 190 
dB) from the two GI airgun array. The 180 and 190 dB level shut-down 
criteria are applicable to cetaceans and pinnipeds, respectively, as 
specified by NMFS (2000) and would be used to establish the exclusion 
and buffer zones.
    Received sound levels have been modeled by L-DEO for a number of 
airgun configurations, including two 45 in \3\ Nucleus G airguns, in 
relation to distance and direction from the airguns (see Figure 2 of 
the IHA application). In addition, propagation measurements of pulses 
from two GI airguns have been reported for shallow water (approximately 
30 m [98.4 ft] depth) in the Gulf of Mexico (Tolstoy et al., 2004). 
However, measurements were not made for the two GI airguns in deep 
water. The model does not allow for bottom interactions, and is most 
directly applicable to deep water. Based on the modeling, estimates of 
the maximum distances from the GI airguns where sound levels are 
predicted to be 190,

[[Page 15084]]

180, and 160 dB re 1 [micro]Pa (rms) in intermediate and deep water 
were determined (see Table 2 above).
    Empirical data concerning the 190, 180, and 160 dB (rms) distances 
were acquired for various airgun arrays based on measurements during 
the acoustic verification studies conducted by L-DEO in the northern 
Gulf of Mexico in 2003 (Tolstoy et al., 2004) and 2007 to 2008 (Tolstoy 
et al., 2009). Results of the 18 and 36 airgun arrays are not relevant 
for the two GI airguns to be used in the proposed low-energy seismic 
survey because the airgun arrays are not the same size or volume. The 
empirical data for the 6, 10, 12, and 20 airgun arrays indicate that, 
for deep water, the L-DEO model tends to overestimate the received 
sound levels at a given distance (Tolstoy et al., 2004). Measurements 
were not made for the two GI airgun array in deep water; however, SIO 
proposes to use the safety radii predicted by L-DEO's model for the 
proposed GI airgun operations in intermediate and deep water, although 
they are likely conservative given the empirical results for the other 
arrays.
    Based on the modeling data, the outputs from the pair of 45 in \3\ 
GI airguns proposed to be used during the low-energy seismic survey are 
considered a low-energy acoustic source in the NSF/USGS PEIS (2011) for 
marine seismic research. A low-energy seismic source was defined in the 
NSF/USGS PEIS as an acoustic source whose received level is less than 
or equal to180 dB at 100 m (including any single or any two GI airguns 
and a single pair of clustered airguns with individual volumes of less 
than or equal to 250 in \3\). The NSF/USGS PEIS also established for 
these low-energy sources a standard exclusion zone of 100 m for all 
low-energy sources in water depths greater than 100 m. This standard 
100 m exclusion zone would be used during the proposed low-energy 
seismic survey using the pair of 45 in \3\ GI airguns. The 180 and 190 
dB (rms) radii are the current Level A harassment shut-down criteria 
applicable to cetaceans and pinnipeds, respectively; these levels were 
used to establish exclusion zones. Therefore, the assumed 180 and 190 
dB radii are 100 m for intermediate and deep water. If the PSO detects 
a marine mammal within or about to enter the appropriate exclusion 
zone, the airguns would be shut down immediately.
    Speed and Course Alterations--If a marine mammal is detected 
outside the exclusion zone and, based on its position and direction of 
travel (relative motion), is likely to enter the exclusion zone, 
changes of the vessel's speed and/or direct course would be considered 
if this does not compromise operational safety or damage the deployed 
equipment. This would be done if operationally practicable while 
minimizing the effect on the planned science objectives. For marine 
seismic surveys towing large streamer arrays, course alterations are 
not typically implemented due to the vessel's limited maneuverability. 
However, the Revelle would be towing a relatively short hydrophone 
streamer, so its maneuverability during operations with the hydrophone 
streamer would not be limited as vessels towing long streamers, thus 
increasing the potential to implement course alterations, if necessary. 
After any such speed and/or course alteration is begun, the marine 
mammal activities and movements relative to the seismic vessel would be 
closely monitored to ensure that the marine mammal does not approach 
within the applicable exclusion zone. If the marine mammal appears 
likely to enter the exclusion zone, further mitigation actions would be 
taken, including further speed and/or course alterations, and/or shut-
down of the airgun(s). Typically, during airgun operations, the source 
vessel is unable to change speed or course, and one or more alternative 
mitigation measures would need to be implemented.
    Shut-Down Procedures--If a marine mammal is detected outside the 
exclusion zone for the airgun(s) but is likely to enter the exclusion 
zone, and the vessel's speed and/or course cannot be changed to avoid 
having the animal enter the exclusion zone, SIO would shut-down the 
operating airgun(s) before the animal is within the exclusion zone. 
Likewise, if a marine mammal is already within the exclusion zone when 
first detected, the airguns would be shut-down immediately.
    Following a shut-down, SIO would not resume airgun activity until 
the marine mammal has cleared the exclusion zone, or until the PSO is 
confident that the animal has left the vicinity of the vessel. SIO 
would consider the animal to have cleared the exclusion zone if:
     A PSO has visually observed the animal leave the exclusion 
zone, or
     A PSO has not sighted the animal within the exclusion zone 
for 15 minutes for species with shorter dive durations (i.e., small 
odontocetes and pinnipeds), or 30 minutes for species with longer dive 
durations (i.e., mysticetes and large odontocetes, including sperm, 
dwarf and pygmy sperm, killer, and beaked whales).
    Although power-down procedures are often standard operating 
practice for seismic surveys, they are not proposed to be used during 
this planned low-energy seismic survey because powering down from two 
airguns to one airgun would make only a small difference in the 
exclusion zone(s) that probably would not be enough to allow continued 
one-airgun operations if a marine mammal came within the exclusion zone 
for two airguns.
    Ramp-Up Procedures--Ramp-up of an airgun array provides a gradual 
increase in sound levels, and involves a step-wise increase in the 
number and total volume of airguns firing until the full volume of the 
airgun array is achieved. The purpose of a ramp-up is to ``warn'' 
marine mammals in the vicinity of the airguns and to provide the time 
for them to leave the area, avoiding any potential injury or impairment 
of their hearing abilities. SIO would follow a ramp-up procedure when 
the airgun array begins operating after a specified period without 
airgun operations or when a shut-down has exceeded that period. SIO 
proposes that, for the present cruise, this period would be 
approximately 15 minutes. SIO, L-DEO, USGS, NSF, and ASC have used 
similar periods (approximately 15 minutes) during previous low-energy 
seismic surveys.
    Ramp-up would begin with a single GI airgun (45 in \3\). The second 
GI airgun (45 in \3\) would be added after 5 minutes. During ramp-up, 
the PSOs would monitor the exclusion zone, and if marine mammals are 
sighted, a shut-down would be implemented as though both GI airguns 
were operational.
    If the complete exclusion zone has not been visible for at least 30 
minutes prior to the start of operations in either daylight or 
nighttime, SIO would not commence the ramp-up. Given these provisions, 
it is likely that the airgun array would not be ramped-up from a 
complete shut-down during low light conditions, at night, or in thick 
fog, (i.e., poor visibility conditions) because the outer part of the 
exclusion zone for that array would not be visible during those 
conditions. If one airgun has been operating, ramp-up to full power 
would be permissible during low light, at night, or in poor visibility, 
on the assumption that marine mammals would be alerted to the 
approaching seismic vessel by the sounds from the single airgun and 
could move away if they choose. SIO would not initiate a ramp-up of the 
airguns if a marine mammal is sighted within or near the applicable 
exclusion zones during day or night. NMFS refers the reader to Figure 
2, which presents a flowchart representing the ramp-up and shut-down 
protocols described in this notice.
BILLING CODE 3510-22-P

[[Page 15085]]

[GRAPHIC] [TIFF OMITTED] TN20MR15.001

BILLING CODE 3510-22-C

Proposed Mitigation Conclusions

    NMFS has carefully evaluated the applicant's proposed mitigation 
measures and has considered a range of other measures in the context of 
ensuring that NMFS prescribes the means of effecting the least 
practicable impact on the affected marine mammal species and stocks and 
their habitat. NMFS's evaluation of potential measures included 
consideration of the following factors in relation to one another:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure is expected to minimize adverse impacts 
to marine mammals;
    (2) The proven or likely efficacy of the specific measure to 
minimize adverse impacts as planned; and
    (3) The practicability of the measure for applicant implementation.
    Any mitigation measure(s) prescribed by NMFS should be able to 
accomplish, have a reasonable likelihood of accomplishing (based on 
current science), or contribute to the accomplishment of one or more of 
the general goals listed below:
    (1) Avoidance of minimization of injury or death of marine mammals 
wherever possible (goals 2, 3, and 4 may contribute to this goal).
    (2) A reduction in the numbers of marine mammals (total number or

[[Page 15086]]

number at biologically important time or location) exposed to received 
levels of airguns, or other activities expected to result in the take 
of marine mammals (this goal may contribute to 1, above, or to reducing 
harassment takes only).
    (3) A reduction in the number of time (total number or number at 
biologically important time or location) individuals would be exposed 
to received levels of airguns, or other activities expected to result 
in the take of marine mammals (this goal may contribute to 1, above, or 
to reducing harassment takes only).
    (4) A reduction in the intensity of exposures (either total number 
or number at biologically important time or location) to received 
levels of airguns, or other activities, or other activities expected to 
result in the take of marine mammals (this goal may contribute to a, 
above, or to reducing the severity of harassment takes only).
    (5) Avoidance or minimization of adverse effects to marine mammal 
habitat, paying special attention to the food base, activities that 
block or limit passage to or from biologically important areas, 
permanent destruction of habitat, or temporary destruction/disturbance 
of habitat during a biologically important time.
    (6) For monitoring directly related to mitigation--an increase in 
the probability of detecting marine mammals, thus allowing for more 
effective implementation of the mitigation.
    Based on NMFS's evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS or recommended by the public, 
NMFS has preliminarily determined that the proposed mitigation measures 
provide the means of effecting the least practicable impact on marine 
mammal species or stocks and their habitat, paying particular attention 
to rookeries, mating grounds, and areas of similar significance.

Proposed Monitoring and Reporting

    In order to issue an ITA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth ``requirements pertaining to 
the monitoring and reporting of such taking.'' The MMPA implementing 
regulations at 50 CFR 216.104(a)(13) indicate that requests for IHAs 
must include the suggested means of accomplishing the necessary 
monitoring and reporting that would result in increased knowledge of 
the species and of the level of taking or impacts on populations of 
marine mammals that are expected to be present in the proposed action 
area. SIO submitted a marine mammal monitoring plan as part of the IHA 
application. It can be found in Section 13 of the IHA application. The 
plan may be modified or supplemented based on comments or new 
information received from the public during the public comment period.
    Monitoring measures prescribed by NMFS should accomplish one or 
more of the following general goals:
    (1) An increase in the probability of detecting marine mammals, 
both within the mitigation zone (thus allowing for more effective 
implementation of the mitigation) and in general to generate more data 
to contribute to the analyses mentioned below;
    (2) An increase in our understanding of how many marine mammals are 
likely to be exposed to levels of sound (airguns) that we associate 
with specific adverse effects, such as behavioral harassment, TTS, or 
PTS;
    (3) An increase in our understanding of how marine mammals respond 
to stimuli expected to result in take and how anticipated adverse 
effects on individuals (in different ways and to varying degrees) may 
impact the population, species, or stock (specifically through effects 
on annual rates of recruitment or survival) through any of the 
following methods:
     Behavioral observations in the presence of stimuli 
compared to observations in the absence of stimuli (need to be able to 
accurately predict received level, distance from source, and other 
pertinent information);
     Physiological measurements in the presence of stimuli 
compared to observations in the absence of stimuli (need to be able to 
accurately predict received level, distance from source, and other 
pertinent information); and
     Distribution and/or abundance comparisons in times or 
areas with concentrated stimuli versus times or areas without stimuli;
    (4) An increased knowledge of the affected species; and
    (5) An increase in our understanding of the effectiveness of 
certain mitigation and monitoring measures.

Proposed Monitoring

    SIO proposes to sponsor marine mammal monitoring during the 
proposed project, in order to implement the proposed mitigation 
measures that require real-time monitoring and to satisfy the 
anticipated monitoring requirements of the IHA. SIO's proposed 
``Monitoring Plan'' is described below this section. The monitoring 
work described here has been planned as a self-contained project 
independent of any other related monitoring projects that may be 
occurring simultaneously in the same regions. SIO is prepared to 
discuss coordination of their monitoring program with any related work 
that might be done by other groups insofar as this is practical and 
desirable.

Vessel-Based Visual Monitoring

    PSOs would be based aboard the seismic source vessel and would 
watch for marine mammals near the vessel during daytime airgun 
operations and during any ramp-ups of the airguns at night. PSOs would 
also watch for marine mammals near the seismic vessel for at least 30 
minutes prior to the start of airgun operations and after an extended 
shut-down (i.e., greater than approximately 15 minutes for this 
proposed low-energy seismic survey). When feasible, PSOs would conduct 
observations during daytime periods when the seismic system is not 
operating (such as during transits) for comparison of sighting rates 
and behavior with and without airgun operations and between acquisition 
periods. Based on PSO observations, the airguns would be shut-down when 
marine mammals are observed within or about to enter a designated 
exclusion zone.
    During airgun operations in the Southwest Pacific Ocean, East of 
New Zealand, at least three PSOs would be based aboard the Revelle. At 
least one PSO would stand watch at all times while the Revelle is 
operating airguns during the proposed low-energy seismic survey; this 
procedure would also be followed when the vessel is in transit. SIO 
would appoint the PSOs with NMFS's concurrence. The lead PSO would be 
experienced with marine mammal species in the Pacific Ocean and/or off 
the east coast of New Zealand, the second and third PSOs would receive 
additional specialized training from the lead PSO to ensure that they 
can identify marine mammal species commonly found in the Southwest 
Pacific Ocean. Observations would take place during ongoing daytime 
operations and ramp-ups of the airguns. During the majority of seismic 
operations, at least one PSO would be on duty from observation 
platforms (i.e., the best available vantage point on the source vessel) 
to monitor marine mammals near the seismic vessel. PSO(s) would be on 
duty in shifts no longer than 4 hours in duration. Other crew would 
also be instructed to assist in detecting marine mammals and 
implementing mitigation requirements (if practical). Before the start 
of the low-energy seismic survey, the crew would be given additional 
instruction on how to do so.
    The Revelle is a suitable platform for marine mammal observations 
and

[[Page 15087]]

would serve as the platform from which PSOs would watch for marine 
mammals before and during airgun operations. The Revelle has been used 
for marine mammal observations during the routine California 
Cooperative Oceanic Fisheries Investigations (CalCOFI). Two locations 
are likely as observation stations onboard the Revelle. Observing 
stations are located at the 02 level, with PSO eye level at 
approximately 10.4 m (34 ft) above the waterline and the PSO would have 
a good view around the entire vessel. At a forward-centered position on 
the 02 deck, the view is approximately 240[deg] around the vessel; and 
one atop the aft hangar, with an aft-centered view includes the 100 m 
radius around the GI airguns. The PSO eye level on the bridge is 
approximately 15 m (49.2 ft) above sea level. PSOs would work on the 
enclosed bridge and adjoining aft steering station during any inclement 
weather.
    Standard equipment for PSOs would be reticle binoculars and optical 
range finders. Night-vision equipment would be available at night and 
low-light conditions during the cruise. The PSOs would be in 
communication with ship's officers on the bridge and scientists in the 
vessel's operations laboratory, so they can advise promptly of the need 
for avoidance maneuvers or seismic source shut-down. During daylight, 
the PSO(s) would scan the area around the vessel systematically with 
reticle binoculars (e.g., 7 x 50 Fujinon FMTRC-SX), Big-eye binoculars 
(e.g., 25 x 150 Fujinon MT), optical range-finders (to assist with 
distance estimation), and the naked eye. These binoculars would have a 
built-in daylight compass. Estimating distances is done primarily with 
the reticles in the binoculars. The optical range-finders are useful in 
training PSOs to estimate distances visually, but are generally not 
useful in measuring distances to animals directly. At night, night-
vision equipment would be available. The PSO(s) would be in direct 
(radio) wireless communication with ship's officers on the bridge and 
scientists in the vessel's operations laboratory during seismic 
operations, so they can advise the vessel operator, science support 
personnel, and the science party promptly of the need for avoidance 
maneuvers or a shut-down of the seismic source.
    When a marine mammal is detected within or about to enter the 
designated exclusion zone, the airguns would immediately be shut-down, 
unless the vessel's speed and/or course can be changed to avoid having 
the animal enter the exclusion zone. The PSO(s) would continue to 
maintain watch to determine when the animal is outside the exclusion 
zone by visual confirmation. Airgun operations would not resume until 
the animal is confirmed to have left the exclusion zone, or is 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, 
dwarf and pygmy sperm, killer, and beaked whales).

PSO Data and Documentation

    PSOs would record data to estimate the numbers of marine mammals 
exposed to various received sound levels and to document apparent 
disturbance reactions or lack thereof. Data would be used to estimate 
numbers of animals potentially ``taken'' by harassment. They would also 
provide information needed to order a shut-down of the airguns when a 
marine mammal is within or near the exclusion zone. Observations would 
also be made during daylight periods when the Revelle is underway 
without seismic airgun operations (i.e., transits to, from, and through 
the study area) to collect baseline biological data.
    When a sighting is made, the following information about the 
sighting would be recorded:
    1. Species, group size, age/size/sex categories (if determinable), 
behavior when first sighted and after initial sighting, heading (if 
consistent), bearing and distance from seismic vessel, sighting cue, 
apparent reaction to the seismic source or vessel (e.g., none, 
avoidance, approach, paralleling, etc.), and behavioral pace.
    2. Time, location, heading, speed, activity of the vessel 
(including number of airguns operating and whether in state of ramp-up 
or shut-down), sea state, wind force, visibility, cloud cover, and sun 
glare.
    The data listed under (2) would also be recorded at the start and 
end of each observation watch, and during a watch whenever there is a 
change in one or more of the variables.
    All observations, as well as information regarding ramp-ups or 
shut-downs, would be recorded in a standardized format. Data would be 
entered into an electronic database. The data accuracy would be 
verified by computerized data validity checks as the data are entered 
and by subsequent manual checking of the database by the PSOs at sea. 
These procedures would allow initial summaries of data to be prepared 
during and shortly after the field program, and would facilitate 
transfer of the data to statistical, graphical, and other programs for 
further processing and archiving.
    Results from the vessel-based observations would provide the 
following information:
    1. The basis for real-time mitigation (airgun shut-down).
    2. Information needed to estimate the number of marine mammals 
potentially taken by harassment, which must be reported to NMFS.
    3. Data on the occurrence, distribution, and activities of marine 
mammals in the area where the seismic study is conducted.
    4. Information to compare the distance and distribution of marine 
mammals relative to the source vessel at times with and without airgun 
operations.
    5. Data on the behavior and movement patterns of marine mammals 
seen at times with and without airgun operations.

Proposed Reporting

    SIO would submit a comprehensive report to NMFS and NSF within 90 
days after the end of the cruise. The report would describe the 
operations that were conducted and sightings of marine mammals near the 
operations. The report submitted to NMFS and NSF would provide full 
documentation of methods, results, and interpretation pertaining to all 
monitoring. The 90-day report would summarize the dates and locations 
of airgun operations and all marine mammal sightings (i.e., dates, 
times, locations, activities, and associated seismic survey 
activities). The report would include, at a minimum:
     Summaries of monitoring effort--total hours, total 
distances, and distribution of marine mammals through the study period 
accounting for Beaufort sea state and other factors affecting 
visibility and detectability of marine mammals;
     Analyses of the effects of various factors influencing 
detectability of marine mammals including Beaufort sea state, number of 
PSOs, and fog/glare;
     Species composition, occurrence, and distribution of 
marine mammals sightings including date, water depth, numbers, age/
size/gender, and group sizes, and analyses of the effects of airgun 
operations;
     Sighting rates of marine mammals during periods with and 
without airgun operations (and other variables that could affect 
detectability);
     Initial sighting distances versus airgun operations state;
     Closest point of approach versus airgun operations state;

[[Page 15088]]

     Observed behaviors and types of movements versus airgun 
operations activity state;
     Numbers of sightings/individuals seen versus airgun 
operations state; and
     Distribution around the source vessel versus airgun 
operations state.
    The report would also include estimates of the number and nature of 
exposures that could result in ``takes'' of marine mammals by 
harassment or in other ways. NMFS would review the draft report and 
provide any comments it may have, and SIO would incorporate NMFS's 
comments and prepare a final report. After the report is considered 
final, it would be publicly available on the NMFS Web site at: http://www.nmfs.noaa.gov/pr/permits/incidental/.
    Reporting Prohibited Take--In the unanticipated event that the 
specified activity clearly causes the take of a marine mammal in a 
manner prohibited by this IHA, such as an injury (Level A harassment), 
serious injury or mortality (e.g., ship-strike, gear interaction, and/
or entanglement), SIO would immediately cease the specified activities 
and immediately report the incident to the Chief of the Permits and 
Conservation Division, Office of Protected Resources, NMFS at 301-427-
8401 and/or by email to [email protected] and 
[email protected]. The report must include the following 
information:
     Time, date, and location (latitude/longitude) of the 
incident;
     Name and type of vessel involved;
     Vessel's speed during and leading up to the incident;
     Description of the incident;
     Status of all sound source use in the 24 hours preceding 
the incident;
     Water depth;
     Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, and visibility);
     Description of all marine mammal observations in the 24 
hours preceding the incident;
     Species identification or description of the animal(s) 
involved;
     Fate of the animal(s); and
     Photographs or video footage of the animal(s) (if 
equipment is available).
    Activities shall not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS shall work with SIO to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. SIO may not resume their 
activities until notified by NMFS via letter or email, or telephone.
    Reporting an Injured or Dead Marine Mammal With an Unknown Cause of 
Death--In the event that SIO discover an injured or dead marine mammal, 
and the lead PSO determines that the cause of the injury or death is 
unknown and the death is relatively recent (i.e., in less than a 
moderate state of decomposition), SIO shall immediately report the 
incident to the Chief of the Permits and Conservation Division, Office 
of Protected Resources, NMFS, at 301-427-8401, and/or by email to 
[email protected] and [email protected]. The report must 
include the same information identified in the paragraph above. 
Activities may continue while NMFS reviews the circumstances of the 
incident. NMFS shall work with SIO to determine whether modifications 
in the activities are appropriate.
    Reporting an Injured or Dead Marine Mammal Not Related to the 
Activities--In the event that SIO discovers an injured or dead marine 
mammal, and the lead PSO determines that the injury or death is not 
associated with or related to the activities authorized in the IHA 
(e.g., previously wounded animal, carcass with moderate or advanced 
decomposition, or scavenger damage), SIO shall report the incident to 
the Chief of the Permits and Conservation Division, Office of Protected 
Resources, NMFS, at 301-427-8401, and/or by email to 
[email protected] and [email protected], within 24 hours 
of discovery. SIO shall provide photographs or video footage (if 
available) or other documentation of the stranded animal sighting to 
NMFS. Activities may continue while NMFS reviews the circumstances of 
the incident.

Estimated Take by Incidental Harassment

    Except with respect to certain activities not pertinent here, the 
MMPA defines ``harassment'' as: Any act of pursuit, torment, or 
annoyance which (i) has the potential to injure a marine mammal or 
marine mammal stock in the wild [Level A harassment]; or (ii) has the 
potential to disturb a marine mammal or marine mammal stock in the wild 
by causing disruption of behavioral patterns, including, but not 
limited to, migration, breathing, nursing, breeding, feeding, or 
sheltering [Level B harassment].

      Table 4--NMFS's Current Underwater Acoustic Exposure Criteria
------------------------------------------------------------------------
                                       Criterion
            Criterion                 definition           Threshold
------------------------------------------------------------------------
                     Impulsive (non-explosive) sound
------------------------------------------------------------------------
Level A harassment (injury).....  Permanent           180 dB re 1 [mu]Pa-
                                   threshold shift     m (root means
                                   (PTS) (Any level    square [rms])
                                   above that which    (cetaceans)
                                   is known to cause  190 dB re 1 [mu]Pa-
                                   TTS).               m (rms)
                                                       (pinnipeds)
Level B harassment..............  Behavioral          160 dB re 1 [mu]Pa-
                                   disruption (for     m (rms)
                                   impulsive noise).
Level B harassment..............  Behavioral          120 dB re 1 [mu]Pa-
                                   disruption (for     m (rms)
                                   continuous noise).
------------------------------------------------------------------------

    Level B harassment is anticipated and proposed to be authorized as 
a result of the proposed low-energy seismic survey in the Southwest 
Pacific Ocean, East of New Zealand. Acoustic stimuli (i.e., increased 
underwater sound) generated during the operation of the seismic airgun 
array are expected to result in the behavioral disturbance of some 
marine mammals. NMFS's current underwater exposure criteria for 
impulsive sound are detailed in Table 4 (above). There is no evidence 
that the planned activities for which SIO seek the IHA could result in 
injury, serious injury, or mortality. The required mitigation and 
monitoring measures would minimize any potential risk for injury, 
serious injury, or mortality.
    The following sections describe SIO's methods to estimate take by 
incidental harassment and present the applicant's estimates of the 
numbers of marine mammals that could be affected. The estimates are 
based on a consideration of the number of marine mammals that could be 
harassed during the approximately 135 hours and 1,250 km of seismic 
airgun operations with the two GI airgun array to be used.
    There are no known systematic aircraft- or ship-based surveys 
conducted for marine mammals stock assessments and very limited 
population information available for marine mammals in offshore waters 
of the Southwest Pacific Ocean off the east coast of New Zealand. For 
most cetacean species, SIO and NMFS used densities from extensive NMFS 
Southwest Fisheries Science Center (SWFSC) cruises (Ferguson and 
Barlow, 2001, 2003; Barlow, 2003, 2010; Forney, 2007) in one province 
of Longhurst's

[[Page 15089]]

(2006) pelagic biogeography, the California Current Province (CALC). 
That province is similar to the South Subtropical Convergence Province 
(SSTC) in which the proposed low-energy seismic survey is located, in 
that productivity is high and large pelagic fish such as tuna occur. 
Specifically, SIO and NMFS used the 1986 to 1996 data from blocks 35, 
36, 47, 48, 59, and 60 of Ferguson and Barlow (2001, 2003), the 2001 
data from Barlow (2003) for the Oregon, Washington, and California 
strata, and the 2005 and 2008 data from Forney (2007) and Barlow 
(2010), respectively, for the two strata combined. The densities used 
were effort-weighted means for the 10 locations (blocks or States). The 
surveys off California, Oregon, and Washington were conducted up to 
approximately 556 km (300.2 nmi) offshore, and most of those data were 
from offshore areas that overlap with the above blocks selected from 
Ferguson and Barlow (2001, 2003).
    For pinnipeds, SIO and NMFS used the densities in Bonnell et al. 
(1992) of northern fur seals (Callorhinus ursinus) and northern 
elephant seals in offshore areas of the western U.S. (the only species 
regularly present in offshore areas there) to estimate the numbers of 
pinnipeds that might be present off New Zealand.
    The marine mammal species that would be encountered during the 
proposed low-energy seismic survey would be different from those 
sighted during surveys off the western U.S. and in the Eastern Tropical 
Pacific Ocean. However, the overall abundances of species groups with 
generally similar habitat requirements are expected to be roughly 
similar. Thus, SIO and NMFS used the data described above to estimate 
the group densities of beaked whales, delphinids, small whales, and 
mysticetes in the proposed study area. SIO and NMFS then estimated the 
relative abundance of individual southern species within the species 
groups using various surveys and other information from areas near the 
study area, and general information on species' distributions such as 
latitudinal ranges and group sizes. Group densities from northern 
species were multiplied by their estimated relative abundance off New 
Zealand divided by the relative abundance for all species in the 
species group to derive estimates for the southern species (see Table 3 
of the IHA application).
    Densities for several cetacean species are available for the 
Southern Ocean (Butterworth et al., 1994), as follows: (1) For 
humpback, sei, fin, blue, sperm, killer, and pilot whales in Antarctic 
Management areas I to VI south of 60[deg] South, based on the 1978/1979 
to 1984 and 1985/1986 to 1990/1991 IWC/IDCR circumpolar sighting survey 
cruises, and (2) for humpback, sei, fin, blue, and sperm whales 
extrapolated to latitudes 30 to 40[deg] South, 40 to 50[deg] South, 50 
to 60[deg] South based on Japanese scouting vessel data from 1965/1966 
to 1977/1978 and 1978/1979 to 1987/1988. SIO and NMFS calculated 
densities based on abundance and surface areas given in Butterworth et 
al. (1994) and used the weighted or mean density for the Regions V and/
or VI (whichever is available) due to locations that represent foraging 
areas or distributions for animals that are likely to move past New 
Zealand during northerly migrations or breed in New Zealand waters.
    The densities used for purposes of estimating potential take do not 
take into account the patchy distributions of marine mammals in an 
ecosystem, at least on the moderate to fine scales over which they are 
known to occur. Instead, animals are considered evenly distributed 
throughout the assessed study area and seasonal movement patterns are 
not taken into account, as none are available. Although there is some 
uncertainty about the representativeness of the data and the 
assumptions used in the calculations below, the approach used here is 
believed to be the best available approach, using the best available 
science.

 Table 5--Estimated Densities and Possible Number of Marine Mammal Species That Might Be Exposed to Greater Than or Equal to 160 dB (Airgun Operations)
 During SIO's Proposed Low-Energy Seismic Survey (Approximately 1,250 km of Tracklines/Approximately 1,154 km \2\ Ensonified Area for Airgun Operations)
                                          in the Southwest Pacific Ocean, East of New Zealand, May to June 2015
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                       Calculated
                                                        take from
                                                     seismic airgun
                                      Density U.S.     operations
                                       West Coast/       (i.e.,                                                  Approximate
                                     Southern Ocean/    estimated     Proposed take                             percentage of
              Species                 estimate used     number of     authorization      Abundance \4\       population estimate    Population trend \6\
                                       (number of      individuals         \3\                               (proposed take) \5\
                                      animals/1,000    exposed to
                                       km\2\) \1\     sound levels
                                                      >=160 dB re 1
                                                       [mu]Pa) \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Mysticetes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Southern right whale...............    0.98/NA/0.98            1.13               2  8,000 to 15,000--      0.03--Worldwide.       Increasing at 7 to 8%
                                                                                      Worldwide. 12,000--    0.02--Southern         per year.
                                                                                      Southern Hemisphere.   Hemisphere. 0.07--
                                                                                      2,700--Sub-Antarctic   Sub-Antarctic New
                                                                                      New Zealand.           Zealand.
Pygmy right whale..................    0.39/NA/0.39            0.45               2  NA...................  NA...................  NA.
Humpback whale.....................  0.98/0.25/0.25            0.29               2  35,000 to 42,000--     <0.01--Southern        Increasing.
                                                                                      Southern Hemisphere.   Hemisphere.
Antarctic minke whale..............    0.59/NA/0.59            0.68               2  720,000 to 750,000--   <0.01--Southern        Stable.
                                                                                      Southern Hemisphere.   Hemisphere.

[[Page 15090]]

 
Minke whale (including dwarf minke     0.59/NA/0.59            0.68               2  720,000 to 750,000--   <0.01--Southern        NA.
 whale sub-species).                                                                  Southern Hemisphere.   Hemisphere.
Bryde's whale......................    0.20/NA/0.20            0.23               2  At least 30,000 to     <0.01--Worldwide.      NA.
                                                                                      40,000--Worldwide.     <0.01--Northwestern
                                                                                      21,000--Northwestern   Pacific Ocean <0.01.
                                                                                      Pacific Ocean 48,109.
Sei whale..........................  0.59/0.08/0.08            0.09               2  80,000--Worldwide.     <0.01--Worldwide.      NA.
                                                                                      10,000--South of       0.02--South of
                                                                                      Antarctic              Antarctic
                                                                                      Convergence.           Convergence.
Fin whale..........................  0.59/0.13/0.13            0.15               2  140,000--Worldwide.    <0.01--Worldwide.      NA.
                                                                                      15,000--South of       0.01--South of
                                                                                      Antarctic              Antarctic
                                                                                      Convergence.           Convergence.
Blue whale.........................  0.59/0.05/0.05            0.06               2  8,000 to 9,000--       0.03--Worldwide.       NA.
                                                                                      Worldwide. 2,300--     0.09--True Southern
                                                                                      True Southern          Hemisphere. 0.13--
                                                                                      Hemisphere. 1,500--    Pygmy.
                                                                                      Pygmy.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Odontocetes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sperm whale........................  1.62/1.16/1.16            1.34              10  360,000--Worldwide.    <0.01--Worldwide.      NA.
                                                                                      30,000--South of       0.03--South of
                                                                                      Antarctic              Antarctic
                                                                                      Convergence.           Convergence.
Pygmy sperm whale..................    0.97/NA/0.97            1.12               5  NA...................  NA...................  NA.
Cuvier's beaked whale..............    0.69/NA/0.69            0.80               2  600,000..............  <0.01................  NA
Shepherd's beaked whale............    0.46/NA/0.46            0.53               3  600,000..............  <0.01................  NA.
Southern bottlenose whale..........    0.46/NA/0.46            0.53               2  50,000--South of       <0.01--South of        NA.
                                                                                      Antarctic              Antarctic
                                                                                      Convergence 600,000.   Convergence <0.01.
Andrew's beaked whale..............    0.46/NA/0.46            0.53               2  600,000..............  <0.01................  NA.
Blainville's beaked whale..........    0.23/NA/0.23            0.27               2  600,000..............  <0.01................  NA.
Gray's beaked whale................    0.92/NA/0.92            1.06               2  600,000..............  <0.01................  NA.
Hector's beaked whale..............    0.46/NA/0.46            0.53               2  600,000..............  <0.01................  NA.
Spade-toothed beaked whale.........    0.23/NA/0.23            0.27               2  600,000..............  <0.01................  NA.
Strap-toothed beaked whale.........    0.69/NA/0.69            0.80               3  600,000..............  <0.01................  NA.
Killer whale.......................  0.45/5.70/5.70            6.58              12  80,000--South of       0.02--South of         NA.
                                                                                      Antarctic              Antarctic
                                                                                      Convergence.           Convergence.
False killer whale.................    0.27/NA/0.27            0.31              10  NA...................  NA...................  NA.

[[Page 15091]]

 
Long-finned pilot whale............  0.27/6.41/6.41            7.40              20  200,000--South of      0.01--South of         NA.
                                                                                      Antarctic              Antarctic
                                                                                      Convergence.           Convergence.
Short-finned pilot whale...........    0.45/NA/0.45            0.52              20  At least 600,000--     <0.01--Worldwide.....  NA.
                                                                                      Worldwide.
Bottlenose dolphin.................  81.55/NA/81.55           94.11              95  At least 614,000--     0.02--Worldwide......  NA.
                                                                                      Worldwide.
Dusky dolphin......................  81.55/NA/81.55           94.11              95  12,000 to 20,000--New  0.79--New Zealand....  NA.
                                                                                      Zealand.
Hector's dolphin...................  32.62/NA/32.62           37.64              38  7,400................  0.51.................  Declining.
Hourglass dolphin..................  48.93/NA/48.93           56.47              57  144,000 to 150,000--   0.04--South of         NA.
                                                                                      South of Antarctic     Antarctic
                                                                                      Convergence.           Convergence.
Short-beaked common dolphin........      163.10/NA/          188.22             189  At least 3,500,000--   <0.01--Worldwide.....  NA.
                                             163.10                                   Worldwide.
Southern right whale dolphin.......  48.93/NA/48.93           56.46              57  NA...................  NA...................  NA.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Pinnipeds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Southern elephant seal.............    5.11/NA/5.11            5.90               6  640,000 to 650,000--   <0.01--Worldwide or    Increasing,
                                                                                      Worldwide. 470,000--   South Georgia Island.  decreasing, or
                                                                                      South Georgia Island                          stable depending on
                                                                                      607,000.                                      breeding population.
New Zealand fur seal...............  12.79/NA/12.79           14.76              15  135,000--Worldwide.    0.01--Worldwide.       Increasing.
                                                                                      50,000 to 100,000--    0.03--New Zealand.
                                                                                      New Zealand.
--------------------------------------------------------------------------------------------------------------------------------------------------------
NA = Not available or not assessed.
\1\ Densities based on sightings from NMFS SWFSC, IWC, and Bonnell et al. (2012) data.
\2\ Calculated take is estimated density multiplied by the area ensonified to 160 dB (rms) around the proposed seismic tracklines, increased by 25% for
  contingency.
\3\ Adjusted to account for average group size.
\4\ See population estimates for marine mammal species in Table 3 (above).
\5\ Total proposed authorized takes expressed as percentages of the species or regional populations.
\6\ Jefferson et al. (2008).

    Numbers of marine mammals that might be present and potentially 
disturbed are estimated based on the available data about marine mammal 
distribution and densities in the U.S. west coast and Southern Ocean as 
a proxy for the proposed study area off the east coast of New Zealand. 
SIO estimated the number of different individuals that may be exposed 
to airgun sounds with received levels greater than or equal to 160 dB 
re 1 [micro]Pa (rms) for seismic airgun operations on one or more 
occasions by considering the total marine area that would be within the 
160 dB radius around the operating airgun array on at least one 
occasion and the expected density of marine mammals in the area (in the 
absence of the low-energy seismic survey). The number of possible 
exposures can be estimated by considering the total marine area that 
would be within the 160 dB radius (the diameter is 400 m multiplied by 
2 for deep water depths, the diameter is 600 m multiplied by 2 for 
intermediate water depths) around the operating airguns, including 
areas of overlap. The spacing of tracklines is 500 m (1,640.4 ft) in 
the smaller grids and 1,250 m (4,101.1 ft) in the larger grids. Overlap 
was measured using GIS and was minimal (area with overlap is equal to 
1.13 multiplied by the area without overlap). The take estimates were 
calculated without overlap. The 160 dB radii are based on acoustic 
modeling data for the airguns that may be used during the proposed 
action (see SIO's IHA application). During the proposed low-energy 
seismic survey, the transect lines are widely spaced relative to the 
160 dB distance. As summarized in Table 2 (see Table 1 and Figure 2 of 
the IHA application), the modeling results for the proposed low-energy 
seismic airgun array indicate the received levels are dependent on 
water depth. Since the majority of the proposed airgun operations would 
be conducted in

[[Page 15092]]

waters 100 to 1,000 m deep or greater than 1,000 m deep, the buffer 
zone of 600 m or 400 m, respectively, for the two 45 in\3\ GI airguns 
was used.
    The number of different individuals potentially exposed to received 
levels greater than or equal to 160 dB re 1 [micro]Pa (rms) from 
seismic airgun operations was calculated by multiplying:
    (1) The expected species density (in number/km\2\), times.
    (2) The anticipated area to be ensonified to that level during 
airgun operations (excluding overlap).
    The area expected to be ensonified was determined by entering the 
planned tracklines into MapInfo GIS using the GIS to identify the 
relevant areas by ``drawing'' the applicable 160 dB (rms) isopleth 
around each trackline, and then calculating the total area within the 
isopleth. Applying the approach described above, approximately 1,153.6 
km\2\ (including the 25% contingency [approximately 923 km\2\ without 
contingency]) would be ensonified within the 160 dB isopleth for 
seismic airgun operations on one or more occasions during the proposed 
low-energy seismic survey. The total ensonified area (1,154 km\2\ 
[336.5 nmi\2\]) was calculated by adding 847 km\2\ (246.9 nmi\2\) in 
deep water, 76 km\2\ (22.2 nmi\2\), and 230.8 km\2\ (67.3 nmi\2\) for 
the 25% contingency. The take calculations within the study sites do 
not explicitly add animals to account for the fact that new animals 
(i.e., turnover) not accounted for in the initial density snapshot 
could also approach and enter the area ensonified above 160 dB for 
seismic airgun operations. However, studies suggest that many marine 
mammals would avoid exposing themselves to sounds at this level, which 
suggests that there would not necessarily be a large number of new 
animals entering the area once the seismic survey started. Because this 
approach for calculating take estimates does not account for turnover 
in the marine mammal populations in the area during the course of the 
proposed low-energy seismic survey, the actual number of individuals 
exposed may be underestimated. However, any underestimation is likely 
offset by the conservative (i.e., probably overestimated) line-
kilometer distances (including the 25% contingency) used to calculate 
the survey area, and the fact the approach assumes that no cetaceans or 
pinnipeds would move away or toward the tracklines as the Revelle 
approaches in response to increasing sound levels before the levels 
reach 160 dB for seismic airgun operations, which is likely to occur 
and which would decrease the density of marine mammals in the survey 
area. Another way of interpreting the estimates in Table 6 is that they 
represent the number of individuals that would be expected (in absence 
of a seismic program) to occur in the waters that would be exposed to 
greater than or equal to 160 dB (rms) for seismic airgun operations.
    SIO's estimates of exposures to various sound levels assume that 
the proposed low-energy seismic survey would be carried out in full; 
however, the ensonified areas calculated using the planned number of 
line-kilometers has been increased by 25% to accommodate lines that may 
need to be repeated, equipment testing, etc. As is typical during 
offshore seismic surveys, inclement weather and equipment malfunctions 
would be likely to cause delays and may limit the number of useful 
line-kilometers of airgun operations that can be undertaken. The 
estimates of the numbers of marine mammals potentially exposed to 160 
dB (rms) received levels are precautionary and probably overestimate 
the actual numbers of marine mammals that could be involved. These 
estimates assume that there would be no weather, equipment, or 
mitigation delays that limit the airgun operations, which is highly 
unlikely.
    Table 5 shows the estimates of the number of different individual 
marine mammals anticipated to be exposed to greater than or equal to 
160 dB re 1 [mu]Pa (rms) for seismic airgun operations during the low-
energy seismic survey if no animals moved away from the survey vessel. 
The total proposed take authorization is given in the column that is 
fourth from the left of Table 5.

Encouraging and Coordinating Research

    SIO and NSF would coordinate the planned marine mammal monitoring 
program associated with the proposed low-energy seismic survey with 
other parties that express interest in this activity and area. SIO and 
NSF would coordinate with applicable U.S. agencies (e.g., NMFS) and the 
government of New Zealand, and would comply with their requirements. 
The proposed low-energy seismic survey falls under Level 3 of the 
``Code of Conduct for minimizing acoustic disturbance to marine mammals 
from seismic survey operations'' issued by New Zealand. Level 3 seismic 
surveys are exempt from the provisions of the Code of Conduct.

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

    Section 101(a)(5)(D) of the MMPA also requires NMFS to determine 
that the authorization would not have an unmitigable adverse impact on 
the availability of marine mammal species or stocks for subsistence 
use. There are no relevant subsistence uses of marine mammals 
implicated by this action (in the Southwest Pacific Ocean, East of New 
Zealand study area). Therefore, NMFS has determined that the total 
taking of affected species or stocks would not have an unmitigable 
adverse impact on the availability of such species or stocks for taking 
for subsistence purposes.

Analysis and Preliminary Determinations

Negligible Impact

    Negligible impact is ``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'' (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of Level B harassment takes, 
alone, is not enough information on which to base an impact 
determination. In addition to considering estimates of the number of 
marine mammals that might be ``taken'' through behavioral harassment, 
NMFS must consider other factors, such as the likely nature of any 
responses (their intensity, duration, etc.) and the context of any 
responses (critical reproductive time or location, migration, etc.), as 
well as the number and nature of estimated Level A harassment takes, 
the number of estimated mortalities, effects on habitat, and the status 
of the species.
    In making a negligible impact determination, NMFS evaluated factors 
such as:
    (1) The number of anticipated serious injuries and or mortalities;
    (2) The number and nature of anticipated injuries;
    (3) The number, nature, intensity, and duration of takes by Level B 
harassment (all of which are relatively limited in this case);
    (4) The context in which the takes occur (e.g., impacts to areas of 
significance, impacts to local populations, and cumulative impacts when 
taking into account successive/contemporaneous actions when added to 
baseline data);

[[Page 15093]]

    (5) 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);
    (6) Impacts on habitat affecting rates of recruitment/survival; and
    (7) The effectiveness of monitoring and mitigation measures.
    NMFS has preliminarily determined that the specified activities 
associated with the marine seismic survey are not likely to cause PTS, 
or other (non-auditory) injury, serious injury, or death, based on the 
analysis above and the following factors:
    (1) The likelihood that, given sufficient notice through relatively 
slow ship speed, marine mammals are expected to move away from a noise 
source that is annoying prior to its becoming potentially injurious;
    (2) The availability of alternate areas of similar habitat value 
for marine mammals to temporarily vacate the survey area during the 
operation of the airgun(s) to avoid acoustic harassment;
    (3) The potential for temporary or permanent hearing impairment is 
relatively low and would likely be avoided through the implementation 
of the required monitoring and mitigation measures (including shut-down 
measures); and
    (4) The likelihood that marine mammal detection ability by trained 
PSOs is high at close proximity to the vessel.
    No injuries, serious injuries, or mortalities are anticipated to 
occur as a result of the SIO's planned low-energy seismic survey, and 
none are proposed to be authorized by NMFS. Table 5 of this document 
outlines the number of requested Level B harassment takes that are 
anticipated as a result of these activities. Due to the nature, degree, 
and context of Level B (behavioral) harassment anticipated and 
described in this notice (see ``Potential Effects on Marine Mammals'' 
section above), the activity is not expected to impact rates of annual 
recruitment or survival for any affected species or stock, particularly 
given NMFS's and the applicant's proposed mitigation, monitoring, and 
reporting measures to minimize impacts to marine mammals. Additionally, 
the low-energy seismic survey 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 hr cycle). 
Behavioral reactions to noise exposure (such as disruption of critical 
life functions, displacement, or avoidance of important habitat) are 
more likely to be significant if they last more than one diel cycle or 
recur on subsequent days (Southall et al., 2007). While airgun 
operations are anticipated to occur on consecutive days, the estimated 
duration of the survey would not last more than a total of 
approximately 27 operational days. Additionally, the low-energy seismic 
survey would be increasing sound levels in the marine environment in a 
relatively small area surrounding the vessel (compared to the range of 
the animals), which is constantly travelling over distances, so 
individual animals likely would only be exposed to and harassed by 
sound for less than a day.
    As mentioned previously, NMFS estimates that 32 species of marine 
mammals under its jurisdiction could be potentially affected by Level B 
harassment over the course of the IHA. The population estimates for the 
marine mammal species that may be taken by Level B harassment were 
provided in Table 3 and 5 of this document. As shown in those tables, 
the proposed takes represent small proportions of the overall 
populations of these marine mammal species where abundance estimates 
are available (i.e., less than 1%).
    Of the 32 marine mammal species under NMFS jurisdiction that may or 
are known to likely occur in the study area, six are listed as 
threatened or endangered under the ESA: Southern right, humpback, sei, 
fin, blue, and sperm whales. These species are also considered depleted 
under the MMPA. None of the other marine mammal species that may be 
taken are listed as depleted under the MMPA. Of the ESA-listed species, 
incidental take has been requested to be authorized for six species. As 
mitigation to reduce impacts to the affected species or stocks, SIO 
would be required to cease airgun operations if any marine mammal 
enters designated exclusion zones. No injury, serious injury, or 
mortality is expected to occur for any of these species, and due to the 
nature, degree, and context of the Level B harassment anticipated, and 
the activity is not expected to impact rates of recruitment or survival 
for any of these species.
    NMFS has preliminarily determined that, provided that the 
aforementioned mitigation and monitoring measures are implemented, the 
impact of conducting a low-energy marine seismic survey in the 
Southwest Pacific Ocean, May to June 2015, may result, at worst, in a 
modification in behavior and/or low-level physiological effects (Level 
B harassment) of certain species of marine mammals.
    While behavioral modifications, including temporarily vacating the 
area during the operation of the airgun(s), may be made by these 
species to avoid the resultant acoustic disturbance, the availability 
of alternate areas for species to move to and the short and sporadic 
duration of the research activities, have led NMFS to preliminary 
determine that the taking by Level B harassment from the specified 
activity would have a negligible impact on the affected species in the 
specified geographic region. Due to the nature, degree, and context of 
Level B (behavioral) harassment anticipated and described (see 
``Potential Effects on Marine Mammals'' section above) in this notice, 
the proposed activity is not expected to impact rates of annual 
recruitment or survival for any affected species or stock, particularly 
given the NMFS and applicant's proposal to implement mitigation and 
monitoring measures would minimize impacts to marine mammals. 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 proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from SIO's proposed low-energy seismic survey would have a 
negligible impact on the affected marine mammal species or stocks.

Small Numbers

    As mentioned previously, NMFS estimates that 32 species of marine 
mammals under its jurisdiction could be potentially affected by Level B 
harassment over the course of the IHA. The population estimates for the 
marine mammal species that may be taken by Level B harassment were 
provided in Tables 3 and 5 of this document.
    The estimated numbers of individual cetaceans and pinnipeds that 
could be exposed to seismic sounds with received levels greater than or 
equal to 160 dB re 1 [mu]Pa (rms) during the proposed low-energy 
seismic survey (including a 25% contingency) are in Table 5 of this 
document. Of the cetaceans, 2 southern right, 2 pygmy right, 2 
humpback, 2 Antarctic minke, 2 minke, 2 Bryde's, 2 sei, 2 fin, 2 blue, 
and 10 sperm whales could be taken by Level B harassment during the 
proposed low-energy seismic survey, which would represent 0.03, 
unknown, 0.1, less than 0.01, less than 0.01, less than 0.01, less than 
0.01, less than 0.01, 0.03, and 0.03% of the affected worldwide or 
regional populations, respectively. In addition, 5 pygmy sperm, 2 
Cuvier's beaked, 3 Shepherd's beaked, 2 southern bottlenose, 2 Andrew's 
beaked, 2 Blainville's beaked, 2 Gray's beaked,

[[Page 15094]]

2 Hector's beaked, 2 spade-toothed beaked, and 3 strap-toothed beaked 
could be taken be Level B harassment during the proposed low-energy 
seismic survey, which would represent unknown, less than 0.01, less 
than 0.01, less than 0.01, less than 0.01, less than 0.01, less than 
0.01, less than 0.01, less than 0.01, and less than 0.01% of the 
affected worldwide or regional populations, respectively. Of the 
delphinids, 12 killer whales, 10 false killer whales, 20 long-finned 
pilot whales, 20 short-finned pilot whales, 95 bottlenose dolphins, 95 
dusky dolphins, 38 Hector's dolphins, 57 hourglass dolphins, 189 short-
beaked common dolphins, and 57 southern right whale dolphins could be 
taken by Level B harassment during the proposed low-energy seismic 
survey, which would represent 0.02, unknown, 0.01, less than 0.01, 
0.02, 0.79, 0.51, 0.04, less than 0.01, and unknown of the affected 
worldwide or regional populations, respectively. Of the pinnipeds, 15 
New Zealand fur seals and 6 southern elephant seals could be taken by 
Level B harassment during the proposed low-energy seismic survey, which 
would represent 0.01 and less than 0.01 of the affected worldwide or 
regional population, respectively.
    No known current worldwide or regional population estimates are 
available for 4 species under NMFS's jurisdiction that could 
potentially be affected by Level B harassment over the course of the 
IHA. These species are the pygmy right, pygmy sperm, and false killer 
whales and southern right whale dolphins. Pygmy right whales have a 
circumglobal distribution and occur throughout coastal and oceanic 
waters in the Southern Hemisphere (between 30 to 55[deg] South) 
(Jefferson et al., 2008). Pygmy sperm whales occur in deep waters on 
the outer continental shelf and slope in tropical to temperate waters 
of the Atlantic, Indian, and Pacific Oceans. False killer whales 
generally occur in deep offshore tropical to temperate waters (between 
50[deg] North to 50[deg] South) of the Atlantic, Indian, and Pacific 
Oceans (Jefferson et al., 2008). Southern right whale dolphins have a 
circumpolar distribution and generally occur in deep temperate to sub-
Antarctic waters in the Southern Hemisphere (between 30 to 65[deg] 
South) (Jefferson et al., 2008). Based on these distributions and 
preferences of these species, NMFS concludes that the requested take of 
these species likely represent small numbers relative to the affected 
species' overall population sizes.
    NMFS makes its small numbers determination based on the numbers of 
marine mammals that would be taken relative to the populations of the 
affected species or stocks. The proposed take estimates all represent 
small numbers relative to the affected species or stock size (i.e., all 
are less than 1%), with the exception of the four species (i.e., pygmy 
right, pygmy sperm, and false killer whales and southern right whale 
dolphins) for which a qualitative rationale was provided.

Endangered Species Act

    Of the species of marine mammals that may occur in the proposed 
survey area, six are listed as endangered under the ESA: The southern 
right, humpback, sei, fin, blue, and sperm whales. Under section 7 of 
the ESA, NSF, on behalf of SIO, has initiated formal consultation with 
the NMFS, Office of Protected Resources, Endangered Species Act 
Interagency Cooperation Division, on this proposed low-energy seismic 
survey. NMFS's Office of Protected Resources, Permits and Conservation 
Division, has initiated formal consultation under section 7 of the ESA 
with NMFS's Office of Protected Resources, Endangered Species Act 
Interagency Cooperation Division, to obtain a Biological Opinion 
evaluating the effects of issuing the IHA on threatened and endangered 
marine mammals and, if appropriate, authorizing incidental take. NMFS 
would conclude formal section 7 consultation prior to making a 
determination on whether or not to issue the IHA. If the IHA is issued, 
in addition to the mitigation and monitoring requirements included in 
the IHA, NSF and SIO would be required to comply with the Terms and 
Conditions of the Incidental Take Statement corresponding to NMFS's 
Biological Opinion issued to both NSF and SIO, and NMFS's Office of 
Protected Resources.

National Environmental Policy Act

    With SIO's complete IHA application, NSF and SIO provided NMFS a 
``Draft Environmental Analysis of a Low-Energy Marine Geophysical 
Survey by the R/V Roger Revelle in the Southwest Pacific Ocean, East of 
New Zealand, May to June 2015,'' (Draft Environmental Analysis), 
prepared by LGL Limited, Environmental Research Associates, on behalf 
of NSF and SIO. The Draft Environmental Analysis analyzes the direct, 
indirect, and cumulative environmental impacts of the proposed 
specified activities on marine mammals, including those listed as 
threatened or endangered under the ESA. NMFS, after independently 
reviewing and evaluating the document for sufficiency and compliance 
with Council on Environmental Quality (CEQ) NEPA regulations and NOAA 
Administrative Order 216-6 Sec.  5.09(d), will conduct a separate NEPA 
analysis and prepare a ``Draft Environmental Assessment on the Issuance 
of an Incidental Harassment Authorization to the Scripps Institution of 
Oceanography to Take Marine Mammals by Harassment Incidental to a Low-
Energy Marine Geophysical Survey in the Southwest Pacific Ocean, East 
of New Zealand, May to June 2015,'' and decide whether to sign a 
Finding of No Significant Impact (FONSI), prior to making a 
determination on the issuance of the IHA.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to SIO for conducting the low-energy seismic survey in the 
Southwest Pacific Ocean, East of New Zealand, provided the previously 
mentioned mitigation, monitoring, and reporting requirements are 
incorporated. This section contains a draft of the IHA itself. The 
wording contained in this section is proposed for inclusion in the IHA 
(if issued). The proposed IHA language is provided below:
    The NMFS hereby authorizes the Scripps Institution of Oceanography, 
8602 La Jolla Shores Drive, La Jolla, California 92037, under section 
101(a)(5)(D) of the Marine Mammal Protection Act (MMPA) (16 U.S.C. 
1371(a)(5)(D)), to harass small numbers of marine mammals incidental to 
a low-energy marine geophysical (seismic) survey conducted by the R/V 
Roger Revelle (Revelle) in the Southwest Pacific Ocean, East of New 
Zealand, May to June 2015:
    1. Effective Dates
    This Authorization is valid from May 18, 2015 through July 30, 
2015.
    2. Specified Activity and Geographic Region
    This Authorization is valid only for SIO's activities associated 
with low-energy seismic survey, bathymetric profile, and heat-flow 
probe measurements conducted aboard the Revelle that shall occur in the 
following specified geographic area:
    (a) In selected regions of the Southwest Pacific Ocean off the east 
coast of New Zealand. The survey sites are located in the Exclusive 
Economic Zone, outside of territorial waters (located between 
approximately 38.5 and 42.5[deg] South, and between 174 and 180[deg] 
East). Water depths in the survey area are expected to be approximately 
200 to 3,000 m. No airgun operations would occur in shallow (less than 
100

[[Page 15095]]

m) water depths. Airgun operations would take approximately 135 hours 
in total and 1,250 km, and the remainder of the time would be spent in 
transit and collecting heat-flow measurements and sediment core 
samples. The low-energy seismic survey would be conducted as specified 
in SIO's IHA application and the associated NSF and SIO Environmental 
Analysis.
    3. This Authorization does not permit incidental takes of marine 
mammals in the territorial sea of foreign nations, as the MMPA does not 
apply in those waters. The territorial sea extends at the most 22.2 
kilometers (km) (12 nautical miles [nmi]) from the baseline of a 
coastal State.
    4. Species Authorized and Level of Takes
    (a) The incidental taking of marine mammals, by Level B harassment 
only, is limited to the following species in the waters of the 
Southwest Pacific Ocean, East of New Zealand:
    (i) Mysticetes--see Table 5 (above) for authorized species and take 
numbers.
    (ii) Odontocetes--see Table 5 (above) for authorized species and 
take numbers.
    (iii) Pinnipeds--see Table 5 (above) for authorized species and 
take numbers.
    (iv) If any marine mammal species are encountered during seismic 
activities that are not listed in Table 5 (above) for authorized taking 
and are likely to be exposed to sound pressure levels (SPLs) greater 
than or equal to 160 dB re 1 [mu]Pa (rms) for seismic airgun 
operations, then the SIO must alter speed or course or shut-down the 
airguns to prevent take.
    (b) The taking by injury (Level A harassment), serious injury, or 
death of any of the species listed in Condition 4(a) above or the 
taking of any kind of any other species of marine mammal is prohibited 
and may result in the modification, suspension, or revocation of this 
Authorization.
    5. The sources authorized for taking by Level B harassment are 
limited to the following acoustic sources, absent an amendment to this 
Authorization:
    A two Generator Injector (GI) airgun array (each with a discharge 
volume of 45 cubic inches [in\3\]) with a total volume of 90 in\3\ (or 
smaller).
    6. Prohibited Take
    The taking of any marine mammal in a manner prohibited under this 
Authorization must be reported immediately to the Office of Protected 
Resources, National Marine Fisheries Service (NMFS), at 301-427-8401.
    7. Mitigation and Monitoring Requirements
    The SIO is required to implement the following mitigation and 
related monitoring requirements when conducting the specified 
activities to achieve the least practicable impact on affected marine 
mammal species or stocks:

Protected Species Observers and Visual Monitoring

    (a) Utilize at least one NMFS-qualified, vessel-based Protected 
Species Observer (PSO) to visually watch for and monitor marine mammals 
near the seismic source vessel during daylight airgun operations (from 
nautical twilight-dawn to nautical twilight-dusk) and before and during 
ramp-ups of airguns day or night. Three PSOs shall be based onboard the 
vessel.
    (i) The Revelle's vessel crew shall also assist in detecting marine 
mammals, when practicable.
    (ii) PSOs shall have access to reticle binoculars (7 x 50 Fujinon) 
equipped with a built-in daylight compass and range reticles, big-eye 
binoculars (25 x 150), optical range finders, and night-vision devices.
    (iii) PSO shifts shall last no longer than 4 hours at a time.
    (iv) PSO(s) shall also make observations during daylight periods 
when the seismic airguns are not operating, when feasible, for 
comparison of animal abundance and behavior.
    (v) PSO(s) shall conduct monitoring while the airgun array and 
streamer(s) are being deployed or recovered from the water.
    (b) PSO(s) shall record the following information when a marine 
mammal is sighted:
    (i) Species, group size, age/size/sex categories (if determinable), 
behavior when first sighted and after initial sighting, heading (if 
consistent), bearing and distance from seismic vessel, sighting cue, 
apparent reaction to the airguns or vessel (e.g., none, avoidance, 
approach, paralleling, etc., and including responses to ramp-up), and 
behavioral pace; and
    (ii) Time, location, heading, speed, activity of the vessel 
(including number of airguns operating and whether in state of ramp-up 
or shut-down), Beaufort sea state and wind force, visibility, and sun 
glare; and
    (iii) The data listed under Condition 7(b)(ii) shall also be 
recorded at the start and end of each observation watch and during a 
watch whenever there is a change in one or more of the variables.

Buffer and Exclusion Zones

    (c) Establish a 160 dB re 1 [mu] Pa (rms) buffer zone, as well as 
a180 dB re 1 [mu] Pa (rms) exclusion zone for cetaceans and a 190 dB re 
1 [mu] Pa (rms) exclusion zone for pinnipeds before the two GI airgun 
array (90 in\3\ total volume) is in operation. See Table 2 (above) for 
distances and buffer and exclusion zones.

Visual Monitoring at the Start of the Airgun Operations

    (d) Visually observe the entire extent of the exclusion zone (180 
dB re 1 [mu] Pa [rms] for cetaceans and 190 dB re 1 [mu] Pa [rms] for 
pinnipeds; see Table 2 [above] for distances) using two NMFS-qualified 
PSOs, for at least 30 minutes prior to starting the airgun array (day 
or night).
    (i) If the PSO(s) sees a marine mammal within the exclusion zone, 
SIO must delay the seismic survey until the marine mammal(s) has left 
the area. If the PSO(s) sees a marine mammal that surfaces, then dives 
below the surface, the PSO(s) shall continue to observe the exclusion 
zone for 30 minutes, and if the PSO sees no marine mammals during that 
time, the PSO should assume that the animal has moved beyond the 
exclusion zone.
    (ii) If for any reason the entire radius cannot be seen for the 
entire 30 minutes (i.e., rough seas, fog, darkness), or if marine 
mammals are near, approaching, or in the exclusion zone, the airguns 
may not be ramped-up. If one airgun is already running at a source 
level of at least 180 dB re 1 [mu] Pa (rms), SIO may start the second 
airgun without observing the entire exclusion zone for 30 minutes 
prior, provided no marine mammals are known to be near the exclusion 
zone (in accordance with Condition 7[e] below).

Ramp-Up Procedures

    (e) Implement a ``ramp-up'' procedure, which means starting with a 
single GI airgun and adding a second GI airgun after five minutes, when 
starting up at the beginning of seismic operations or anytime after the 
entire array has been shut-down for more than 15 minutes. During ramp-
up, the two PSOs shall monitor the exclusion zone, and if marine 
mammals are sighted, a shut-down shall be implemented as though the 
full array (both GI airguns) were operational. Therefore, initiation of 
ramp-up procedures from shut-down requires that the two PSOs be able to 
view the full exclusion zone as described in Condition 7(d) (above).

Shut-Down Procedures

    (f) Shut-down the airgun(s) if a marine mammal is detected within, 
approaches, or enters the relevant exclusion zone (as defined in Table 
2, above). A shut-down means all operating airguns are shut-down (i.e., 
turned off).

[[Page 15096]]

    (g) Following a shut-down, the airgun activity shall not resume 
until the PSO(s) has visually observed the marine mammal(s) exiting the 
exclusion zone and determined it is not likely to return, or has not 
seen the marine mammal within the exclusion zone for 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, dwarf and pygmy sperm, killer, and 
beaked whales).
    (h) Following a shut-down and subsequent animal departure, airgun 
operations may resume, following the ramp-up procedures described in 
Condition 7(e).

Speed or Course Alteration

    (i) Alter speed or course during seismic operations if a marine 
mammal, based on its position and relative motion, appears likely to 
enter the relevant exclusion zone. If speed or course alteration is not 
safe or practicable, or if after alteration the marine mammal still 
appears likely to enter the exclusion zone, further mitigation 
measures, such as a shut-down, shall be taken.

Survey Operations During Low-Light Hours

    (j) Marine seismic surveying may continue into low-light hours if 
such segment(s) of the survey is initiated when the entire relevant 
exclusion zones are visible and can be effectively monitored.
    (k) No initiation of airgun array operations is permitted from a 
shut-down position during low-light hours (such as in dense fog or 
heavy rain) when the entire relevant exclusion zone cannot be 
effectively monitored by the PSO(s) on duty.
    (l) To the maximum extent practicable, schedule seismic operations 
(i.e., shooting airguns) during daylight hours, and heat-flow 
measurements at nighttime hours.
    8. Reporting Requirements
    SIO are required to:
    (a) Submit a draft report on all activities and monitoring results 
to the Office of Protected Resources, NMFS, within 90 days of the 
completion of the Revelle's Southwest Pacific Ocean, East of New 
Zealand cruise. This report must contain and summarize the following 
information:
    (i) Dates, times, locations, heading, speed, weather, sea 
conditions (including Beaufort sea state and wind force), and 
associated activities during all seismic operations and marine mammal 
sightings;
    (ii) Species, number, location, distance from the vessel, and 
behavior of any marine mammals, as well as associated seismic activity 
(e.g., number of shut-downs), observed throughout all monitoring 
activities.
    (iii) An estimate of the number (by species) of marine mammals 
that: (A) Are known to have been exposed to the seismic activity (based 
on visual observation) at received levels greater than or equal to 160 
dB re 1 [mu]Pa (rms) (for seismic airgun operations), and/or 180 dB re 
1 [mu]Pa (rms) for cetaceans and 190 dB re 1 [mu]Pa (rms) for 
pinnipeds, with a discussion of any specific behaviors those 
individuals exhibited; and (B) may have been exposed (based on modeled 
values for the two GI airgun array) to the seismic activity at received 
levels greater than or equal to 160 dB re 1 [mu]Pa (rms) (for seismic 
airgun operations), and/or 180 dB re 1 [mu]Pa (rms) for cetaceans and 
190 dB re 1 [mu]Pa (rms) for pinnipeds, with a discussion of the nature 
of the probable consequences of that exposure on the individuals that 
have been exposed.
    (iv) A description of the implementation and effectiveness of the: 
(A) Terms and Conditions of the Biological Opinion's Incidental Take 
Statement (ITS) (attached); and (B) mitigation measures of the IHA. For 
the Biological Opinion, the report shall confirm the implementation of 
each Term and Condition, as well as any conservation recommendations, 
and describe their effectiveness, for minimizing the adverse effects of 
the action on Endangered Species Act-listed marine mammals.
    (b) Submit a final report to the Chief, Permits and Conservation 
Division, Office of Protected Resources, NMFS, within 30 days after 
receiving comments from NMFS on the draft report. If NMFS decides that 
the draft report needs no comments, the draft report shall be 
considered to be the final report.
    8. Reporting Prohibited Take
    (a) (i) In the unanticipated event that the specified activity 
clearly causes the take of a marine mammal in a manner prohibited by 
this Authorization, such as an injury (Level A harassment), serious 
injury or mortality (e.g., through ship-strike, gear interaction, and/
or entanglement), SIO shall immediately cease the specified activities 
and immediately report the incident to the Chief of the Permits and 
Conservation Division, Office of Protected Resources, NMFS, at 301-427-
8401 and/or by email to [email protected] and 
[email protected]. The report must include the following 
information:
    (ii) Time, date, and location (latitude/longitude) of the incident; 
the name and type of vessel involved; the vessel's speed during and 
leading up to the incident; description of the incident; status of all 
sound source use in the 24 hours preceding the incident; water depth; 
environmental conditions (e.g., wind speed and direction, Beaufort sea 
state, cloud cover, and visibility); description of marine mammal 
observations in the 24 hours preceding the incident; species 
identification or description of the animal(s) involved; the fate of 
the animal(s); and photographs or video footage of the animal (if 
equipment is available).
    Activities shall not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS shall work with SIO to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. SIO may not resume their 
activities until notified by NMFS via letter, email, or telephone.

Reporting an Injured or Dead Marine Mammal With an Unknown Cause of 
Death

    (b) In the event that SIO discover an injured or dead marine 
mammal, and the lead PSO determines that the cause of the injury or 
death is unknown and the death is relatively recent (i.e., in less than 
a moderate state of decomposition), SIO shall immediately report the 
incident to the Chief of the Permits and Conservation Division, Office 
of Protected Resources, NMFS, at 301-427-8401, and/or by email to 
[email protected] and [email protected]. The report must 
include the same information identified in Condition 8(c)(i) above. 
Activities may continue while NMFS reviews the circumstances of the 
incident. NMFS shall work with SIO to determine whether modifications 
in the activities are appropriate.

Reporting an Injured or Dead Marine Mammal Not Related to the 
Activities

    (c) In the event that SIO discovers an injured or dead marine 
mammal, and the lead PSO determines that the injury or death is not 
associated with or related to the activities authorized in Condition 2 
of this Authorization (e.g., previously wounded animal, carcass with 
moderate to advanced decomposition, or scavenger damage), SIO shall 
report the incident to the Chief of the Permits and Conservation 
Division, Office of Protected Resources, NMFS, at 301-427-8401, and/or 
by email to [email protected] and [email protected], 
within 24 hours of the discovery. SIO shall provide photographs or 
video footage (if available) or other documentation of the

[[Page 15097]]

stranded animal sighting to NMFS. Activities may continue while NMFS 
reviews the circumstances of the incident.
    9. Endangered Species Act Biological Opinion and Incidental Take 
Statement
    (a) SIO is required to comply with the Terms and Conditions of the 
ITS corresponding to NMFS's Biological Opinion issued to both NSF and 
SIO, and NMFS's Office of Protected Resources.
    (b) A copy of this Authorization and the ITS must be in the 
possession of all contractors and PSO(s) operating under the authority 
of this Incidental Harassment Authorization.

Request for Public Comments

    NMFS requests comment on our analysis, the draft authorization, and 
any other aspect of the notice of the proposed IHA for SIO's low-energy 
seismic survey. Please include with your comments any supporting data 
or literature citations to help inform our final decision on SIO's 
request for an MMPA authorization. Concurrent with the publication of 
this notice in the Federal Register, NMFS is forwarding copies of this 
application to the Marine Mammal Commission and its Committee of 
Scientific Advisors.

    Dated: March 12, 2015.
Perry Gayaldo,
Deputy Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2015-06261 Filed 3-19-15; 8:45 am]
 BILLING CODE 3510-22-P`