[Federal Register Volume 79, Number 120 (Monday, June 23, 2014)]
[Notices]
[Pages 35642-35676]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2014-14426]
[[Page 35641]]
Vol. 79
Monday,
No. 120
June 23, 2014
Part II
Department of Commerce
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National Oceanic and Atmospheric Administration
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Takes of Marine Mammals Incidental to Specified Activities; Taking
Marine Mammals Incidental to a Marine Geophysical Survey in the
Atlantic Ocean off the Eastern Seaboard, August to September 2014 and
April to August 2015; Notice
Federal Register / Vol. 79 , No. 120 / Monday, June 23, 2014 /
Notices
[[Page 35642]]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XD214
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to a Marine Geophysical Survey in the
Atlantic Ocean off the Eastern Seaboard, August to September 2014 and
April to August 2015
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed Incidental Harassment Authorization; request
for comments.
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SUMMARY: NMFS has received an application from the United States (U.S.)
Geological Survey (USGS), Lamont-Doherty Earth Observatory of Columbia
University (L-DEO), and National Science Foundation (NSF) for an
Incidental Harassment Authorization (IHA) to take marine mammals, by
harassment, incidental to conducting a marine geophysical (seismic)
survey in the Atlantic Ocean off the Eastern Seaboard, August to
September 2014 and April to August 2015. Pursuant to the Marine Mammal
Protection Act (MMPA), NMFS is requesting comments on its proposal to
issue an IHA to USGS to incidentally harass, by Level B harassment
only, 34 species of marine mammals during the specified activity.
DATES: Comments and information must be received no later than July 23,
2014.
ADDRESSES: Comments on the application should be addressed to Jolie
Harrison, Supervisor, 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 noaa.gov">ITP.Goldstein@noaa.gov. Please include 0648-XD214 in
the subject line. Comments sent via email, including all attachments,
must not exceed a 25-megabyte file size. NMFS is not responsible for
email comments sent to addresses other than the one provided here.
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.htm#applications without change. All Personal Identifying
Information (for example, name, address, etc.) voluntarily submitted by
the commenter may be publicly accessible. Do not submit Confidential
Business Information or otherwise sensitive or protected information.
An electronic copy of the application may be obtained by writing to
the address specified above, telephoning the contact listed below (see
FOR FURTHER INFORMATION CONTACT) or visiting the Internet at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications. The following
associated documents are also available at the same internet address:
``Draft Environmental Assessment for Seismic Reflection Scientific
Research Surveys during 2014 and 2015 in Support of Mapping the U.S.
Atlantic Seaboard Extended Continental Margin and Investigating Tsunami
Hazards.'' Documents cited in this notice may also be viewed, by
appointment, during regular business hours, at the aforementioned
address.
The USGS, which is funding the proposed seismic survey, included
with its application a ``Draft Environmental Assessment for Seismic
Reflection Scientific Research Surveys during 2014 and 2015 in Support
of Mapping the U.S. Atlantic Seaboard Extended Continental Margin and
Investigating Tsunami Hazards,'' prepared by RPS Evan-Hamilton, Inc. in
association with YOLO Environmental, Inc., GeoSpatial Strategy Group,
and Ecology and Environment, Inc., on behalf of USGS, which is also
available at the same internet address. Documents cited in this notice
may be viewed, by appointment, during regular business hours, at the
aforementioned address.
FOR FURTHER INFORMATION CONTACT: Howard Goldstein or Jolie Harrison,
Office of Protected Resources, NMFS, 301-427-8401.
SUPPLEMENTARY INFORMATION:
Background
Section 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.),
directs 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 the incidental takings shall be granted if
NMFS finds that the taking will have a negligible impact on the species
or stock(s), and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for subsistence uses (where
relevant), and if the permissible methods of taking 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.''
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 March 27, 2014, NMFS received an application from the USGS, L-
DEO, and NSF (hereafter referred to as USGS) requesting that NMFS issue
an IHA for the take, by Level B harassment only, of small numbers of
marine mammals incidental to conducting a marine seismic survey within
the Exclusive Economic Zone (EEZ) and on the high seas (i.e.,
International Waters) to map the U.S. Atlantic Eastern Seaboard
Extended Continental Shelf (ECS) region and investigate tsunami hazards
during August to September 2014 and April to August 2015. USGS plan to
use one source vessel, the R/V Marcus G. Langseth (Langseth) and a
seismic airgun array and a hydrophone streamer to collect seismic data
as part of the proposed seismic survey in the Atlantic Ocean off the
Eastern Seaboard. In addition to the proposed operation of the seismic
airgun array and hydrophone streamer, USGS intends to operate a multi-
beam echosounder and a sub-bottom profiler continuously during the
seismic operations in order to map the ocean floor. The multi-beam
echosounder and sub-bottom profiler would not be operated during
transits at the beginning and end of the seismic survey. NMFS
determined that the IHA application was adequate and complete on May
14, 2014.
Acoustic stimuli (i.e., increased underwater sound) generated
during the operation of the seismic airgun array are likely to result
in the take of marine mammals. Take, by Level B harassment only, of
individuals of 34 species of marine mammals is anticipated to result
[[Page 35643]]
from the proposed specified activity. Take is not expected to result
from the use of the multi-beam echosounder or sub-bottom profiler, for
reasons discussed in this notice; nor is take expected to result from
collision with the source vessel because it is a single vessel moving
at a relatively slow speed (4.5 knots [kts]; 8.5 kilometers per hour
[km/hr]; 5.3 miles per hour [mph]) during seismic acquisition within
the survey, for a relatively short period of time (approximately two 17
to 18 day legs), and it is likely that any marine mammal would be able
to avoid the vessel.
Description of the Proposed Specified Activity
Overview
USGS plans to conduct a marine seismic survey within the EEZ and on
the high seas to map the U.S. Atlantic Eastern Seaboard ECS region and
investigate tsunami hazards during August to September 2014 and April
to August 2015. USGS proposes to use one source vessel, the Langseth,
and a 36-airgun array and one 8 kilometer (km) (4.3 nautical mile
[nmi]) hydrophone streamer to conduct the conventional seismic survey.
In addition to the operations of airguns, the USGS intends to operate a
multi-beam echosounder and a sub-bottom profiler on the Langseth during
the proposed seismic survey to map the ocean floor.
Dates and Duration
The Langseth would depart from Newark, New Jersey on August 15,
2014. The seismic survey is expected to take approximately 16 days to
complete. Approximately one day transit would be required at the
beginning and end of the program. When the 2014 survey is completed,
the Langseth would then transit to Norfolk, Virginia. The survey
schedule is inclusive of weather and other contingency (e.g., equipment
failure) time. The proposed activities for 2015 would be virtually
identical to the proposed activities for 2014 as geographic area,
duration, and trackline coverage are similar. The exact dates for the
proposed activities in 2015 are uncertain, but are scheduled to occur
within the April to August timeframe. The exact dates of the proposed
activities depend on logistics and weather conditions.
Specified Geographic Region
The proposed survey would be bounded by the following geographic
coordinates:
40.5694[deg] North, -66.5324[deg] West;
38.5808[deg] North, -61.7105[deg] West;
29.2456[deg] North, -72.6766[deg] West;
33.1752[deg] North, -75.8697[deg] West;
39.1583[deg] North, -72.8697[deg] West;
The proposed activities for 2014 would generally occur towards the
periphery of the proposed study area (see Figures 1 and 2 of the IHA
application). The proposed activities for 2015 would survey more of the
central portions of the study area. The tracklines proposed for both
2014 and 2015 would be in International Waters (approximately 80% in
2014 and 90% in 2015) and in the U.S. EEZ. Water depths range from
approximately 1,450 to 5,400 meters (m) (4,593.2 to 17,716.5 feet [ft])
(see Figure 1 and 2 of the IHA application); no survey lines would
extend to water depths less than 1,000 m.
Detailed Description of the Proposed Specified Activity
USGS, Coastal and Marine Geology Program, (Primary Investigator
[PI], Dr. Deborah Hutchinson) proposes to conduct a regional high-
energy, two-dimensional (2D) seismic survey in the northwest Atlantic
Ocean within the U.S. EEZ and extending into International Waters as
far as 648.2 km (350 nmi) from the U.S. coast (see Figure 1 of the IHA
application). Water depths in the survey area range from approximately
1,400 to greater than 5,400 meters (m) (4,593.2 to 17,716.5 feet [ft]).
The proposed seismic survey would be scheduled to occur in two phases;
the first phase during August to September 2014 (for approximately 17
to 18 days), and the second phase between April and August 2015 (for
approximately 17 to 18 days, specific dates to be determined). The
proposed activities for both Phase 1 and Phase 2 are included in this
IHA application (see Figure 2 of the IHA application). Some minor
deviation from these dates is possible, depending on logistics and
weather.
USGS proposes to use conventional seismic methodology to: (1)
Identify the outer limits of the U.S. continental shelf, also referred
to as the ECS as defined by Article 76 of the Convention of the Law of
the Sea; and (2) study the sudden mass transport of sediments down the
continental shelf as submarine landslides that may pose significant
tsunamigenic (i.e., tsunami-related) hazards to the Atlantic and
Caribbean coastal communities.
The proposed survey would involve one source vessel, the Langseth.
The Langseth would deploy an array of 36 airguns as an energy source
with a total volume of approximately 6,600 in\3\. The receiving system
would consist of one 8,000 m (26,246.7 ft) hydrophone streamer. As the
airgun array is towed along the survey lines, the hydrophone streamer
would receive the returning acoustic signals from the towed airgun
array and transfer the data to the on-board processing system. The data
would be processed on-board the Langseth as the survey occurs.
Each proposed leg of the survey (2014 and 2015) would be 17 to 18
days in duration (exclusive of transit and equipment deployment and
recovery) and would comprise of approximately 3,165 km (1,709 nmi) of
tracklines of 2D seismic reflection coverage. The airgun array would
operate continuously during the proposed survey (except for equipment
testing, repairs, implemented mitigation measures, etc.). Data would
continue to be acquired between line changes, as the successive track
segments can be surveyed as almost one continuous line. Line turns of
90 and no greater than 120 degrees would be required to move from one
line segment to the next. The 2014 proposed survey design consists
primarily of the tracklines that run along the periphery of the overall
study area, including several internal tracklines (see Figure 2 of the
IHA application). The 2015 proposed survey design consists of
additional dip and tie lines (i.e., dip lines are lines that are
perpendicular to the north-south trend of the continental margin;
strike lines are parallel to the margin; and tie lines are any line
that connects other lines). The 2015 proposed survey design may be
modified based on the 2014 results.
In addition to the operations of the airgun array, a Kongsberg EM
122 multi-beam echosounder and a Knudsen Model 3260 Chirp sub-bottom
profiler would also be operated from the Langseth continuously during
airgun operations throughout the survey to map the ocean floor. The
multi-beam and sub-bottom profiler would not operate during transits at
the beginning and end of the survey. All planned geophysical data
acquisition activities would be conducted by USGS with on-board
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.
Vessel Specifications
The Langseth, a seismic research vessel owned by the National
Science Foundation (NSF) and operated by the Lamont-Doherty Earth
Observatory of Columbia University (L-DEO), would tow the 36 airgun
array, as well as the hydrophone streamer(s), along predetermined lines
(see Figure 2 of the IHA application). When the Langseth is
[[Page 35644]]
towing the airgun array and the hydrophone streamer(s), the turning
rate of the vessel is limited to three degrees per minute (2.5 km [1.5
mi]). Thus, the maneuverability of the vessel is limited during
operations with the streamer. The vessel would ``fly'' the appropriate
U.S. Coast Guard-approved day shapes (mast head signals used to
communicate with other vessels) and display the appropriate lighting to
designate the vessel has limited maneuverability.
The vessel has a length of 71.5 m (235 ft); a beam of 17.0 m (56
ft); a maximum draft of 5.9 m (19 ft); and a gross tonnage of 3,834.
The Langseth was designed as a seismic research vessel with a
propulsion system designed to be as quiet as possible to avoid
interference with the seismic signals emanating from the airgun array.
The ship is powered by two 3,550 horsepower (hp) Bergen BRG-6 diesel
engines which drive two propellers directly. Each propeller has four
blades and the shaft typically rotates at 750 revolutions per minute.
The vessel also has an 800 hp bowthruster, which is not used during
seismic acquisition. The Langseth's operation speed during seismic data
acquisition is typically 7.4 to 9.3 km per hour (hr) (km/hr) (4 to 5
knots [kts]). When not towing seismic survey gear, the Langseth
typically cruises at 18.5 to 24 km/hr (10 to 12 kts). The Langseth has
a range of 25,000 km (13,499 nmi) (the distance the vessel can travel
without refueling).
The vessel also has an observation tower from which Protected
Species Visual Observers (PSVO) would watch for marine mammals before
and during the proposed airgun operations. When stationed on the
observation platform, the PSVO's eye level would be approximately 21.5
m (71 ft) above sea level providing the PSVO an unobstructed view
around the entire vessel. More details of the Langseth can be found in
the IHA application and 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'' (2011) and the Record of Decision (2012) (NSF/
USGS PEIS).
Acoustic Source Specifications
Seismic Airguns
The Langseth would deploy a 36-airgun array, consisting of two 18
airgun (plus 2 spares) sub-arrays. Each sub-array would have a volume
of approximately 3,300 cubic inches (in\3\) for a total volume of 6,600
in\3\ for the 36-airgun array. The airgun array would consist of a
mixture of Bolt 1500LL and Bolt 1900LLX airguns ranging in size from 40
to 360 in\3\, with a firing pressure of 1,900 pounds per square inch
(psi). The 18 airgun sub-arrays would be configured as two identical
linear arrays or ``strings'' (see Figure 2.11 of the NSF/USGS PEIS).
Each string would have 10 airguns, with the first and last airguns in
the strings spaced 16 m (52.5 ft) apart. Of the 10 airguns, nine
airguns in each string would be fired simultaneously (1,650 in\3\),
whereas the tenth would be kept in reserve as a spare, to be turned on
in case of failure of another airgun. The sub-arrays would be fired
simultaneously during the survey. The two airgun sub-arrays would be
distributed across an area of approximately 12 x 16 m (40 x 52.5 ft)
behind the Langseth and would be towed approximately 140 m (459.3 ft)
behind the vessel. Discharge intervals depend on both the ship's speed.
The shot interval would be 50 m (164 ft) during the study. The shot
interval would be approximately 20 to 24 seconds (s) based on an
assumed boat speed of 4.5 knots. During firing, a brief (approximately
0.1 s) pulse sound is emitted; the airguns would be silent during the
intervening periods. The dominant frequency components range from 2 to
188 Hertz (Hz). The firing pressure of the airgun array is 2,000 pounds
per square inch (psi).
The tow depth of the airgun array would be 9 m (29.5 ft) during the
surveys. Because the actual source is a distributed sound source (36
airguns) rather than a single point source, the highest sound
measurable at any location in the water would be less than the nominal
source level. In addition, the effective source level for sound
propagating in near-horizontal directions would be substantially lower
than the nominal omni-directional source level applicable to downward
propagation because of the directional nature of the sound from the
airgun array (i.e., sound is directed downward).
Hydrophone Streamer
Acoustic signals would be recorded using a system array of one
hydrophone streamer, which would be towed behind the Langseth. The
streamer is Thompson-Marconi SENTRY solid cable construction and is
approximately 8 km long. Cable-leveling birds would be used to keep the
streamer cable and hydrophone at a constant depth. Cable-leveling birds
would be spaced every 300 m (984.3 ft) with extra redundancy at the
head and tail sections.
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 (rms), 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.
Characteristics of the Airgun Pulses
Airguns function by venting high-pressure air into the water, which
creates an air bubble. The pressure signature of an individual airgun
consists of a sharp rise and then fall in pressure, followed by several
positive and negative pressure excursions caused by the oscillation of
the resulting air bubble. The oscillation of the air bubble transmits
sounds downward through the seafloor and the amount of sound
transmitted in the near horizontal directions is reduced. However, the
airgun array also emits sounds that travel horizontally toward non-
target areas.
The nominal source levels of the airgun arrays used by L-DEO on the
Langseth are 236 to 265 dB re 1 [mu]Pa (p-p) and the rms value for a
given airgun pulse is typically 16 dB re 1 [mu]Pa lower than the peak-
to-peak value (Greene, 1997; McCauley et al., 1998, 2000a). However,
the difference between rms and peak or peak-to-peak values for a given
pulse depends on the frequency content and duration of the pulse, among
other factors.
Accordingly, L-DEO has predicted the received sound levels in
relation to distance and direction from the 36 airgun array and the
single Bolt 1900LL 40 in\3\ airgun, which would be used during power-
downs. A detailed description of L-DEO modeling for this
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survey's marine seismic source arrays for protected species mitigation
is provided in the NSF/USGS PEIS (see Appendix H). NMFS refers the
reviewers to the IHA application and NSF/USGS PEIS documents for
additional information.
Predicted Sound Levels for the Airguns
Tolstoy et al. (2009) and Diebold et al. (2010) reported results
for propagation measurements of pulses from the Langseth's 36 airgun,
6,600 in\3\ array in shallow water (approximately 50 m [164 ft]),
intermediate water (a slope site), and deep water depths (approximately
1,600 m [5,249 ft]) in the Gulf of Mexico in 2007 and 2008. Results of
the Gulf of Mexico calibration study (Tolstoy et al., 2009; Diebold et
al., 2010) showed that radii around the airguns for various received
levels varied with water depth and that sound propagation varied with
array tow depth.
The L-DEO used the results from the Gulf of Mexico study to
determine the algorithm for its model that calculates the mitigation
exclusion zones for the 36-airgun array and the single airgun. L-DEO
has used these calculated values to determine buffer (i.e., 160 dB) and
exclusion zones for the 36 airgun array and previously modeled
measurements by L-DEO for the single airgun, to designate exclusion
zones for purposes of mitigation, and to estimate take for marine
mammals in the northwest Atlantic Ocean. A detailed description of the
modeling effort is provided in the NSF/USGS PEIS.
Comparison of the Tolstoy et al. (2009) calibration study with the
L-DEO's model for the Langseth's 36-airgun array indicates that the
model represents the actual received levels, within the first few
kilometers and the locations of the predicted exclusion zones. However,
the model for deep water (greater than 1,000 m; 3,280 ft) overestimated
the received sound levels at a given distance but is still valid for
defining exclusion zones at various tow depths. Because the tow depth
of the array in the calibration study is less shallow (6 m [19.7 ft])
than the tow depths in the proposed survey (9 m [29.5 ft]), L-DEO used
the following correction factors for estimating the received levels
during the proposed surveys (see Table 1). The correction factors are
the ratios of the 160, 180, and 190 dB distances from the modeled
results for the 6,600 in\3\ airgun arrays towed at 6 m (19.7 ft) versus
9, 12, or 15 m (29.5, 39.4, or 49.2 ft) (LGL, 2008). For a single
airgun, the tow depth has minimal effect on the maximum near-field
output and the shape of the frequency spectrum for the single airgun;
thus, the predicted exclusion zones are essentially the same at
different tow depths. The L-DEO's model does not allow for bottom
interactions, and thus is most directly applicable to deep water.
Using the model (airgun array and single airgun), Table 1 (below)
shows the distances at which three rms sound levels are expected to be
received from the 36 airgun array and a single airgun. To avoid the
potential for injury or permanent physiological damage (Level A
harassment), NMFS's (1995, 2000) current practice is that cetaceans and
pinnipeds should not be exposed to pulsed underwater noise at received
levels exceeding 180 dB re 1 [mu]Pa and 190 dB re 1 [mu]Pa,
respectively. L-DEO used these levels to establish the proposed
exclusion zones. If marine mammals are detected within or about to
enter the appropriate exclusion zone, the airguns would be powered-down
(or shut-down, if necessary) immediately. NMFS also assumes that marine
mammals exposed to levels exceeding 160 dB re 1 [mu]Pa may experience
Level B harassment. Table 1 summarizes the predicted distances at which
sound levels (160, 180, and 190 dB [rms]) are expected to be received
from the 36 airgun array and a single airgun operating in deep water
depths.
Table 1--Measured (Array) or Predicted (Single Airgun) Distances to Which Sound Levels >=190, 180, and 160 dB re 1 [mu]Pa (rms) Could Be Received in
Deep Water During the Proposed Seismic Survey in the Northwest Atlantic Ocean Off the Eastern Seaboard, August to September 2014 and April to August
2015
--------------------------------------------------------------------------------------------------------------------------------------------------------
Predicted RMS radii distances (m)
Water depth ------------------------------------------------------------------------------
Sound source and volume Tow depth (m) (m) 160
190 dB 180 dB dB
--------------------------------------------------------------------------------------------------------------------------------------------------------
Single Bolt airgun (40 in\3\)............ 9 >1,000 13 m (42.7 ft) *100 m would 100 m (328.1 ft).......................... 388
be used for pinnipeds as m
well as cetaceans. (1,
273
ft)
.
36 airguns (6,600 in\3\)................. 9 >1,000 286 m (938.3 ft)............ 927 m (3,041.3 ft)........................ 5,7
80
m
(18
,96
3.3
ft)
.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Along with the airgun operations, two additional acoustical data
acquisition systems would be operated from the Langseth continuously
during seismic operations during the survey. The ocean floor would be
mapped with the Kongsberg EM 122 multi-beam echosounder and a Knudsen
320B sub-bottom profiler. These sound sources would be operated
continuously from the Langseth throughout the cruise, except for during
transits at the beginning and end of the proposed survey.
Multi-Beam Echosounder
The Langseth would operate a Kongsberg EM 122 multi-beam
echosounder concurrently during airgun operations to map
characteristics of the ocean floor. The hull-mounted multi-beam
echosounder emits brief pulses of sound (also called a ping) (10.5 to
13, usually 12 kHz) in a fan-shaped beam that extends downward and to
the sides of the ship. The transmitting beamwidth is 1[deg] or 2[deg]
fore-aft and 150[deg] athwartship and the maximum source level is 242
dB re 1 [mu]Pa.
Each ping consists of eight (in water greater than 1,000 m) or four
(less than 1,000 m) successive, fan-shaped transmissions, each
ensonifying a sector that extends 1[deg] fore-aft. Continuous-wave
pulses increase from 2 to 15 milliseconds (ms) long in water depths up
to 2,600 m (8,350.2 ft), and frequency modulated (FM) chirp pulses up
to 100 ms long are used in water greater than 2,600 m. The successive
transmissions span an overall cross-track angular extent of about
150[deg], with 2 ms gaps between the pulses for successive sectors (see
Table 1 of the IHA application).
Sub-Bottom Profiler
The Langseth would also operate a Knudsen Chirp 3260 sub-bottom
profiler
[[Page 35646]]
continuously throughout the cruise simultaneously with the multi-beam
echosounder to map and provide information about the sedimentary
features and bottom topography. The beam is transmitted as a 27[deg]
cone, which is directed downward by a 3.5 kHz transducer in the hull of
the Langseth. The nominal power output is 10 kilowatts (kW), but the
actual maximum radiated power is 3 kW or 222 dB re 1 [micro]Pam. The
ping duration is up to 64 milliseconds (ms). The ping interval is three
to five seconds, depending on water depth. The sub-bottom profiler is
capable of reaching water depths of 10,000 m (32,808.4 ft) and
penetrating tens of meters into the sediments.
Both the multi-beam echosounder and sub-bottom profiler are
operated continuously during survey operations. The multi-beam
echosounder and sub-bottom profiler would not operate during transits
at the beginning and end of the proposed seismic survey. Actual
operating parameters would be established at the time of the survey.
NMFS expects that acoustic stimuli resulting from the proposed
operation of the single airgun or the 36 airgun array has the potential
to harass marine mammals. NMFS does not expect that the movement of the
Langseth, during the conduct of the seismic survey, has the potential
to harass marine mammals because of the relatively slow operation speed
of the vessel (approximately 4.5 knots [kts]; 8.5 km/hr; 5.3 mph)
during seismic acquisition.
Description of the Marine Mammals in the Area of the Proposed Specified
Activity
Forty-five species of marine mammal (37 cetaceans [whales,
dolphins, and porpoises] including 30 odontocetes and 7 mysticetes, 7
pinnipeds [seals and sea lions], and 1 sirenian [manatees]) are known
to occur in the western North Atlantic Ocean study area (Read et al.,
2009; Waring et al., 2013). Of those 45 species of marine mammals, 34
cetaceans and 4 pinnipeds could be found or are likely to occur in the
proposed study area during the spring/summer/fall months. Several of
these species are listed as endangered under the U.S. Endangered
Species Act of 1973 (ESA; 16 U.S.C. 1531 et seq.), including the North
Atlantic right (Eubalaena glacialis), humpback (Megaptera
novaeangliae), sei (Balaenoptera borealis), fin (Balaenoptera
physalus), blue (Balaenoptera musculus), and sperm (Physeter
macrocephalus) whales. Fourteen cetacean species, although present in
the wider western North Atlantic Ocean, are considered rare and likely
would not be found near the proposed study area. The harbor porpoise
(Phocoena phocoena) does not occur in deep offshore waters. The four
pinniped species (harbor [Phoca vitulina], harp [Phoca groenlandica],
gray [Halichoerus grypus], and hooded [Cystophora cristata] seals) are
also considered coastal species (any sightings would be considered
extralimital) and are not known to occur in the deep waters of the
proposed survey area. No pinnipeds are expected to be present in the
proposed study area. The West Indian manatee (Trichechus manatus
latirostris) is listed as endangered under the ESA and is managed by
the U.S. Fish and Wildlife Service and is not considered further in
this proposed IHA notice.
General information on the taxonomy, ecology, distribution,
seasonality and movements, and acoustic capabilities of marine mammals
are given in sections 3.6.1, 3.7.1, and 3.8.1 of the NSF/USGS PEIS. The
general distribution of mysticetes, odontocetes, and pinnipeds in the
North Atlantic Ocean is discussed in sections 3.6.3.4, 3.7.3.4, and
3.8.3.4 of the NSF/USGS PEIS, respectively. In addition, Section 3.1 of
the ``Atlantic OCS Proposed Geological and Geophysical Activities Mid-
Atlantic and South Atlantic Planning Areas Draft Programmatic
Environmental Impact Statement'' (Bureau of Ocean Energy Management,
2012) reviews similar information for all marine mammals that may occur
within the proposed study area.
Various systematic surveys have been conducted throughout the
western North Atlantic Ocean, including within sections of the proposed
study area. Records from the Ocean Biogeographic Information System
(OBIS) database hosted by Rutgers University and Duke University (Read
et al., 2009) were used as the main source of information. The database
includes survey data collected during the Cetaceans and Turtle
Assessment Program (CeTAP) conducted between 1978 and 1982 that
consists of both aerial and vessel-based surveys between Cape Hatteras,
North Carolina, and the Gulf of Maine. The database also includes
survey data collected during the NMFS Northeast Fisheries Science
Center and Southeast Fisheries Science Center stock assessment surveys
conducted in 2004 (surveys between Nova Scotia, Canada, and Florida).
No known current regional or stock abundance estimates are
available in the proposed study area of the northwest Atlantic Ocean
for the Bryde's whale (Balaenoptera edeni), Fraser's (Lagenodelphis
hosei), spinner (Stenella longirostris), and Clymene dolphin (Stenella
clymene), and melon-headed (Peponocephala electra), pygmy killer
(Feresa attenuata), false killer (Pseudorca crassidens), and killer
whales (Orcinus orca). Although NMFS does not have current regional
population or stock abundance estimates for these species in the
northwest Atlantic Ocean, abundance estimates from other areas such as
the northern Gulf of Mexico stock, regional ocean basins (e.g., eastern
tropical Pacific Ocean), or global summation are available. These
abundance estimates are considered the best available information.
Bryde's whales are distributed worldwide in tropical and sub-
tropical waters. In the western North Atlantic Ocean, Bryde's whales
are reported from off the southeastern U.S. and the southern West
Indies to Cabo Frio, Brazil (Leatherwood and Reeves, 1983). No stock of
Bryde's whales has been identified in U.S. waters of the Atlantic
coast. The northern Gulf of Mexico population is considered a separate
stock and has a best abundance estimate of 33 animals. It has been
postulated that the Bryde's whales found in the northern Gulf of Mexico
may represent a resident stock (Schmidly, 1981; Leatherwood and Reeves,
1983).
Fraser's dolphins are distributed worldwide in tropical waters and
are assumed to be part of the cetacean fauna of the tropical western
North Atlantic (Perrin et al., 1994). There are no abundance estimates
for either the western North Atlantic or the northern Gulf of Mexico
stocks. The western North Atlantic population is provisionally being
considered a separate stock for management purposes, although there is
currently no information to differentiate this stock from the northern
Gulf of Mexico stock. The numbers of Fraser's dolphins off the U.S. or
Canadian Atlantic coast are unknown, and seasonal abundance estimates
are not available for this stock, since it was rarely seen in any
surveys. The population size for Fraser's dolphins is unknown; however,
about 289,000 animals occur in the eastern tropical Pacific Ocean
(Jefferson et al., 2008).
Spinner dolphins are distributed in oceanic and coastal tropical
waters (Leatherwood et al., 1976). This is presumably an offshore,
deep-water species, and its distribution in the Atlantic is poorly
known (Schmidly, 1981; Perrin and Gilpatrick, 1994). The western North
Atlantic population of spinner dolphins is provisionally being
considered a separate stock for
[[Page 35647]]
management purposes, although there is currently no information to
differentiate this stock from the northern Gulf of Mexico stock. The
numbers of spinner dolphins off the U.S. or Canadian Atlantic coast are
unknown, and seasonal abundance estimates are not available for this
stock since it was rarely seen in any of the surveys. The best
abundance estimate available for the northern Gulf of Mexico spinner
dolphins is 11,441 animals.
The Clymene dolphin is endemic to tropical and sub-tropical waters
of the Atlantic (Jefferson and Curry, 2003). The western North Atlantic
population of Clymene dolphins is provisionally considered a separate
stock for management purposes, although there is currently no
information to differentiate this stock from the northern Gulf of
Mexico stock. The numbers of Clymene dolphins off the U.S. or Canadian
Atlantic coast are unknown, and seasonal abundance estimates are not
available for this species since it was rarely seen in any surveys. The
best abundance estimate for the Clymene dolphin in the western North
Atlantic was 6,086 in 2003 and represents the first and only estimate
to date for this species in the U.S. Atlantic EEZ; however this
estimate is older than eight years and is deemed unreliable (Wade and
Angliss, 1997; Mullin and Fulling, 2003).
The melon-headed whale is distributed worldwide in tropical to sub-
tropical waters (Jefferson et al., 1994). The western North Atlantic
population is provisionally being considered a separate stock from the
northern Gulf of Mexico stock. The numbers of melon-headed whales off
the U.S. or Canadian Atlantic coast are unknown, and seasonal abundance
estimates are not available for this stock, since it was rarely seen in
any surveys. The best abundance estimate available for northern Gulf of
Mexico melon-headed whales is 2,235 animals.
The pygmy killer whale is distributed worldwide in tropical to sub-
tropical waters and is assumed to be part of the cetacean fauna of the
tropical western North Atlantic (Jefferson et al., 1994). The western
North Atlantic population of pygmy killer whales is provisionally being
considered one stock for management purposes. The numbers of pygmy
killer whales off the U.S. or Canadian Atlantic coast are unknown, and
seasonal abundance estimates are not available for this stock, since it
was rarely seen in any surveys. The best abundance estimate available
for the northern Gulf of Mexico pygmy killer whale is 152 animals.
The false killer whale is distributed worldwide throughout warm
temperate and tropical oceans (Leatherwood and Reeves, 1983). No stock
has been identified for false killer whales in U.S. waters off the
Atlantic coast. The Gulf of Mexico population is provisionally being
considered one stock for management purposes, although there is
currently no information to differentiate this stock from the Atlantic
Ocean stock. The current population size for the false killer whale in
the northern Gulf of Mexico is unknown because the survey data is more
than 8 years old; however, the most recent abundance estimate pooled
from 2003 to 2004 was 777 animals (Wade and Angliss, 1997; Mullin,
2007).
Killer whales are characterized as uncommon or rare in waters of
the U.S. Atlantic EEZ (Katona et al., 1988). Their distribution,
however, extends from the Arctic ice-edge to the West Indies, often in
offshore and mid-ocean areas. The size of the western North Atlantic
stock population off the eastern U.S. coast is unknown. No information
on stock differentiation for the Atlantic Ocean population exists,
although an analysis of vocalizations of killer whales from Iceland and
Norway indicated that whales from these areas may represent different
stocks (Moore et al., 1988). The northern Gulf of Mexico population is
provisionally being considered a separate stock for management
purposes, although there is currently no information to differentiate
this stock from the Atlantic Ocean stock. The best abundance estimate
available for northern Gulf of Mexico killer whales is 28 animals.
There are estimated to be at least approximately 92,500 killer whales
worldwide (i.e., 80,000 south of Antarctic Convergence, 445 in Norway,
8,500 in eastern tropical Pacific Ocean, 1,500 in North America coastal
waters, and 2,000 in Japanese waters) (Jefferson et al., 2008).Table 2
(below) presents information on the abundance, distribution, population
status, and conservation status of the species of marine mammals that
may occur in the proposed study area during August to September 2014
and April to August 2015.
Table 2--The Habitat, Occurrence, Range, Abundance, and Conservation Status of Marine Mammals That May Occur in
or Near the Proposed Seismic Survey Area in the Northwest Atlantic Ocean Off the Eastern Seaboard
[See text and Table 3 in USGS's IHA application for further details]
----------------------------------------------------------------------------------------------------------------
Population
estimate in the
Species Habitat Occurrence Range in North Atlantic ESA MMPA
Atlantic Ocean region/stock/ \1\ \2\
other \3\
----------------------------------------------------------------------------------------------------------------
Mysticetes:
North Atlantic right Pelagic, shelf Regular....... Canada to 455/455 EN D
whale (Eubalaena and coastal. Florida. (Western
glacialis). Atlantic
stock).
Humpback whale (Megaptera Mainly Regular....... Canada to 11,600 \4\/823 EN D
novaeangliae). nearshore, Caribbean. (Gulf of Maine
banks. stock).
Minke whale (Balaenoptera Pelagic and Regular....... Arctic to 138,000 \5\/ NL NC
acutorostrata). coastal. Caribbean. 20,741
(Canadian East
Coast stock).
Bryde's whale Coastal, Rare.......... 40[deg] North NA/NA/33 NL NC
(Balaenoptera edeni). offshore. to 40[deg] (Northern Gulf
South. of Mexico
stock)/20,000
to 30,000 \16\
(North Pacific
Ocean).
Sei whale (Balaenoptera Primarily Rare.......... Canada to New 10,300 \6\/357 EN D
borealis). offshore, Jersey. (Nova Scotia
pelagic. stock).
[[Page 35648]]
Fin whale (Balaenoptera Continental Regular....... Canada to North 26,500 \7\/ EN D
physalus). slope, pelagic. Carolina. 3,522 (Western
North Atlantic
stock).
Blue whale (Balaenoptera Pelagic, shelf, Rare.......... Arctic to 855 \8\/440 EN D
musculus). coastal. Florida. (Western North
Atlantic
stock).
Odontocetes:
Sperm whale (Physeter Pelagic, slope, Regular....... Canada to 13,190 \9\/ EN D
macrocephalus). canyons, deep Caribbean. 2,288 (North
sea. Atlantic
stocks).
Pygmy sperm whale (Kogia Deep waters off Rare.......... Massachusetts NA/3,785 NL NC
breviceps). shelf. to Florida. (Western North
Atlantic
stock).
Dwarf sperm whale (Kogia Deep waters off Rare.......... Massachusetts ............... NL NC
sima). shelf. to Florida.
Cuvier's beaked whale Pelagic, slope, Rare.......... Canada to NA/6,532 NL NC
(Ziphius cavirostris). canyons. Caribbean. (Western North
Atlantic
stock).
Northern bottlenose whale Pelagic........ Rare.......... Arctic to New 40,000 \10\/NA NL NC
(Hyperoodon ampullatus). Jersey. (Western North
Atlantic
stock).
True's beaked whale Pelagic, slope, Rare.......... Canada to NA/7,092 NL NC
(Mesoplodon mirus). canyons. Bahamas. (Western North
Atlantic
stock).
Gervais' beaked whale Pelagic, slope, Rare.......... Canada to ............... NL NC
(Mesoplodon europaeus). canyons. Florida.
Sowerby's beaked whale Pelagic, slope, Rare.......... Canada to ............... NL NC
(Mesoplodon bidens). canyons. Florida.
Blainville's beaked whale Pelagic, slope, Rare.......... Canada to ............... NL NC
(Mesoplodon canyons. Florida.
densirostris).
Bottlenose dolphin Coastal, Regular....... Canada to NA/77,532 NL NC
(Tursiops truncatus). oceanic, shelf Florida. (Western North
break. Atlantic
Offshore
stock).
Atlantic white-sided Shelf and slope Regular....... Greenland to 10,000 to NL NC
dolphin (Lagenorhynchus North Carolina. 100,000s \11\/
acutus). 48,819
(Western North
Atlantic
stock).
Fraser's dolphin Shelf and slope Rare.......... North Carolina NA/NA (Western NL NC
(Lagenodelphis hosei). to Florida. North Atlantic
stock)/289,000
\16\ (eastern
tropical
Pacific Ocean).
Atlantic spotted dolphin Shelf, offshore Regular....... Massachusetts NA/44,715 NL NC
(Stenella frontalis). to Caribbean. (Western North
Atlantic
stock).
Pantropical spotted Coastal, shelf, Regular....... Massachusetts NA/3,333 NL NC
dolphin (Stenella slope. to Florida. (Western North
attenuata). Atlantic
stock).
Striped dolphin (Stenella Off continental Regular....... Canada to NA/54,807 NL NC
coeruleoalba). shelf, Caribbean. (Western North
convergence Atlantic
zones, stock).
upwelling.
Spinner dolphin (Stenella Mainly Rare.......... Maine to NA/NA (Western NL NC
longirostris). nearshore. Caribbean. North Atlantic
stock)/11,441
(Northern Gulf
of Mexico
stock)/
1,250,000 \16\
(eastern
tropical
Pacific Ocean).
Clymene dolphin (Stenella Coastal, shelf, Rare.......... North Carolina NA/NA (Western NL NC
clymene). slope. to Florida. North Atlantic
stock--6,086
in 2003)/129
(Northern Gulf
of Mexico
stock).
Short-beaked common Shelf, pelagic, Regular....... Canada to NA/173,486 NL NC
dolphin (Delphinus seamounts. Georgia. (Western North
delphis). Atlantic
stock).
[[Page 35649]]
Rough-toothed dolphin Pelagic........ Rare.......... New Jersey to NA/271 (Western NL NC
(Steno bredanensis). Florida. North Atlantic
stock).
Risso's dolphin (Grampus Shelf, slope, Regular....... Canada to NA/18,250 NL NC
griseus). seamounts. Florida. (Western North
Atlantic
stock).
Melon-headed whale Deep waters off Rare.......... North Carolina NA/NA (Western NL NC
(Peponocephala electra). shelf. to Florida. North Atlantic
stock)/2,235
(Northern Gulf
of Mexico
stock)/45,000
\16\ (eastern
tropical
Pacific Ocean).
Pygmy killer whale Pelagic........ Rare.......... NA............. NA/NA (Western NL NC
(Feresa attenuata). North Atlantic
stock)/152
(Northern Gulf
of Mexico
stock)/39,000
\16\ (eastern
tropical
Pacific Ocean).
False killer whale Pelagic........ Rare.......... NA............. NA/NA/777 in NL NC
(Pseudorca crassidens). 2003-2004
(Northern Gulf
of Mexico
stock).
Killer whale (Orcinus Pelagic, shelf, Rare.......... Arctic to NA/NA (Western NL NC
orca). coastal. Caribbean. North Atlantic
stock)/28
(Northern Gulf
of Mexico
stock)/At
least ~92,500
\16\ Worldwide.
Short-finned pilot whale Mostly pelagic, Regular....... Massachusetts 780,000 \12\/ NL NC
(Globicephala high relief. to Florida. 21,515 short-
macrorhynchus). finned pilot
whale 26,535
long-finned
pilot whale
(Western North
Atlantic
stock).
Long-finned pilot whale Mostly pelagic. Regular....... Canada to South NL............. NC
(Globicephala melas). Carolina.
Harbor porpoise (Phocoena Shelf, coastal, Rare.......... Canada to North ~500,000 \13\/ NL NC
phocoena). pelagic. Carolina. 79,883 (Gulf
of Maine/Bay
of Fundy
stock).
Pinnipeds:
Harbor seal (Phoca Coastal........ Rare.......... Canada to North NA/70,142 NL NC
vitulina concolor). Carolina. (Western North
Atlantic
stock).
Gray seal (Halichoerus Coastal, Rare.......... Canada to North NA/331,000 NL NC
grypus). pelagic. Carolina. (Western North
Atlantic
stock).
Harp seal (Phoca Ice whelpers, Rare.......... Canada to New 8.6 to 9.6 NL NC
groenlandica). pelagic. Jersey. million \14\/
7.1 million
(Western North
Atlantic
stock).
Hooded seal (Cystophora Ice whelpers, Rare.......... Canada to 600,000/592,100 NL NC
cristata). pelagic. Caribbean. (Western North
Atlantic
stock).
----------------------------------------------------------------------------------------------------------------
NA = Not available or not assessed.
\1\ U.S. Endangered Species Act: EN = Endangered, T = Threatened, DL = Delisted, NL = Not listed.
\2\ U.S. Marine Mammal Protection Act: D = Depleted, NC = Not Classified.
\3\ NMFS Marine Mammal Stock Assessment Reports.
\4\ Best estimate for western North Atlantic 1992 to 1993 (IWC, 2014).
\5\ Best estimate for North Atlantic 2002 to 2007 (IWC, 2014).
\6\ Estimate for the Northeast Atlantic in 1989 (Cattanach et al., 1993).
\7\ Best estimate for North Atlantic 2007 (IWC, 2014) .
\8\ Central and Northeast Atlantic 2001 (Pike et al., 2009).
\9\ North Atlantic (Whitehead, 2002).
\10\ Eastern North Atlantic (NAMMCO, 1995).
\11\ North Atlantic (Reeves et al., 1999).
\12\ Globicephala spp. combined, Central and Eastern North Atlantic (IWC, 2014).
\13\ North Atlantic (Jefferson et al., 2008).
\14\ Northwest Atlantic (DFO, 2012).
\15\ Northwest Atlantic (Andersen et al., 2009).
\16\ Jefferson et al. (2008).
[[Page 35650]]
Further detailed information regarding the biology, distribution,
seasonality, life history, and occurrence of these marine mammal
species in the proposed project area can be found in sections 3 and 4
of USGS's IHA application. 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 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, gear deployment) have been
observed 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 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 will 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 would 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 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, 38 marine mammal species
(34 cetacean and 4 pinniped species) are likely to occur in the
proposed seismic survey area. Of the 34 cetacean species likely to
occur in USGS's proposed action area, 7 are classified as low-frequency
cetaceans (i.e., North Atlantic right, humpback, minke, Bryde's, sei,
fin, and blue whale), 24 are classified as mid-frequency cetaceans
(i.e., sperm, Cuvier's, True's, Gervais', Sowerby's, Blainville's,
Northern bottlenose, melon-headed, pygmy killer, false killer, killer,
short-finned, and long-finned whale, bottlenose, Atlantic white-sided,
Fraser's, Atlantic spotted, pantropical spotted, striped, spinner,
Clymene, short-beaked common, rough-toothed, and Risso's dolphin), and
3 are classified as high-frequency cetaceans (i.e., pygmy sperm and
dwarf sperm whale and harbor porpoise) (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, may have the potential to
cause Level B harassment of marine mammals in the proposed survey area.
The effects of sounds from airgun operations might include one or more
of the following: Tolerance, masking (of natural sounds including
inter- and intra-specific calls), 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; Wright et al., 2007; Tyack, 2009).
Permanent hearing impairment, in the unlikely event that it occurred,
would constitute injury, but temporary threshold shift (TTS) is not an
injury (Southall et al., 2007). Although the possibility cannot be
entirely excluded, it is unlikely that the proposed project would
result in any cases of temporary or permanent hearing impairment, or
any significant non-auditory physical or physiological effects. Based
on the available data and studies described here, some behavioral
disturbance is expected. A more comprehensive review of these issues
can be found in the NSF/USGS PEIS (2011) and L-DEO's ``Draft
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) (Thorpe, 1963; Richardson, et al., 1995),
but because of ecological or physiological requirements, many marine
animals may need to remain in areas where they are exposed to chronic
stimuli (Richardson, et al., 1995).
Numerous studies have shown that pulsed sounds from airguns are
often readily detectable in the water at distances of many kilometers.
Several studies have shown that marine mammals at distances more than a
few kilometers from operating seismic vessels often show no apparent
response (Malme et al., 1985; Richardson et al., 1986; Ljungblad et
al., 1988; McCauley et al., 2000a). 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 and toothed whales, and (less
frequently) pinnipeds have been shown to react behaviorally to airgun
pulses
[[Page 35651]]
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 and pinnipeds are quite variable and depend on
factors such as species, age, and previous exposures of the animal to
human-generated sound.
Masking
The term masking refers to the inability of a subject to recognize
the occurrence of an acoustic stimulus as a result of the interference
of another acoustic stimulus (Clark et al., 2009). Introduced
underwater sound may, through masking, reduce the effective
communication distance of a marine mammal species if the frequency of
the source is close to that used as a signal by the marine mammal, and
if the anthropogenic sound is present for a significant fraction of the
time (Richardson et al., 1995).
Masking effects of pulsed sounds (even from large arrays of
airguns) on marine mammal calls and other natural sounds are expected
to be limited. Because of the intermittent nature and low duty cycle of
seismic airgun pulses, animals can emit and receive sounds in the
relatively quiet intervals between pulses. However, in some situations,
reverberation occurs for much or the entire interval between pulses
(e.g., Simard et al., 2005; Clark and Gagnon, 2006) which could mask
calls. Some baleen and toothed whales are known to continue calling in
the presence of seismic pulses, and their calls can usually be heard
between the seismic pulses (e.g., Richardson et al., 1986; McDonald et
al., 1995; Greene et al., 1999; Nieukirk et al., 2004; Smultea et al.,
2004; Holst et al., 2005a,b, 2006; and Dunn and Hernandez, 2009).
However, Clark and Gagnon (2006) reported that fin whales in the North
Atlantic Ocean went silent for an extended period starting soon after
the onset of a seismic survey in the area. Similarly, there has been
one report that sperm whales ceased calling when exposed to pulses from
a very distant seismic ship (Bowles et al., 1994). However, more recent
studies found that they continued calling in the presence of seismic
pulses (Madsen et al., 2002; Tyack et al., 2003; Smultea et al., 2004;
Holst et al., 2006; and Jochens et al., 2008). Dilorio and Clark (2009)
found evidence of increased calling by blue whales during operations by
a lower-energy seismic source (i.e., sparker). Dolphins and porpoises
commonly are heard calling while airguns are operating (e.g., Gordon et
al., 2004; Smultea et al., 2004; Holst et al., 2005a, b; and Potter et
al., 2007). The sounds important to small odontocetes are predominantly
at much higher frequencies than are the dominant components of airgun
sounds, thus limiting the potential for masking.
Marine mammals are thought to be able to compensate for masking by
adjusting their acoustic behavior through shifting call frequencies,
increasing call volume, and increasing vocalization rates. For example,
blue whales are found to increase call rates when exposed to noise from
seismic surveys in the St. Lawrence Estuary (Dilorio and Clark, 2009).
The North Atlantic right whales 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 (but not limited to) subtle to conspicuous changes in
behavior, movement, and displacement (Nowacek et al., 2007; Tyack,
2009). Reactions to sound, if any, depend on species, state of
maturity, experience, current activity, reproductive state, time of
day, and many other factors (Richardson et al., 1995; Wartzok et al.,
2004; Southall et al., 2007; Weilgart, 2007). These behavioral
reactions are often shown as: Changing durations of surfacing and
dives, number of blows per surfacing, or moving direction and/or speed;
reduced/increased vocal activities; changing/cessation of certain
behavioral activities (such as socializing or feeding); visible startle
response or aggressive behavior (such as tail/fluke slapping or jaw
clapping); avoidance of areas where noise sources are located; and/or
flight responses (e.g., pinnipeds flushing into the water from haul-
outs or rookeries). If a marine mammal does react briefly to an
underwater sound by changing its behavior or moving a small distance,
the impacts of the change are unlikely to be significant to the
individual, let alone the stock or population. However, if a sound
source displaces marine mammals from an important feeding or breeding
area for a prolonged period, impacts on individuals and populations
could be significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007).
The biological significance of many of these behavioral
disturbances is difficult to predict, especially if the detected
disturbances appear minor. However, the consequences of behavioral
modification could be expected to be biologically significant if the
change affects growth, survival, and/or reproduction. Some of these
significant behavioral modifications include:
Change in diving/surfacing patterns (such as those thought
to be causing beaked whale stranding due to exposure to military mid-
frequency tactical sonar);
Habitat abandonment due to loss of desirable acoustic
environment; and
Cessation of feeding or social interaction.
The onset of behavioral disturbance from anthropogenic noise
depends on both external factors (characteristics of noise sources and
their paths) and the receiving animals (hearing, motivation,
experience, demography) and is also difficult to predict (Richardson et
al., 1995; Southall et al., 2007). Given the many uncertainties in
predicting the quantity and types of impacts of noise on marine
mammals, it is common practice to estimate how many mammals would be
present within a particular distance of industrial activities and/or
exposed to a particular level of sound. In most cases, this approach
likely overestimates the numbers of marine mammals that would be
affected in some biologically-important manner.
Baleen Whales--Baleen whales generally tend to avoid operating
airguns, but avoidance radii are quite variable (reviewed in Richardson
et al., 1995; Gordon et al., 2004). Whales are often reported to show
no overt reactions to pulses from large arrays of airguns at distances
beyond a few kilometers, even though the airgun pulses remain well
above ambient noise levels out to much longer distances. However,
baleen whales exposed to strong noise pulses from airguns often react
by deviating from their normal migration route and/or interrupting
their feeding and moving away. In the cases of migrating gray
(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
[[Page 35652]]
substantial fraction of the animals exposed (Malme et al., 1986, 1988;
Richardson et al., 1995). In many areas, seismic pulses from large
arrays of airguns diminish to those levels at distances ranging from 4
to 15 km (2.2 to 8.1 nmi) from the source. A substantial proportion of
the baleen whales within those distances may show avoidance or other
strong behavioral reactions to the airgun array. Subtle behavioral
changes sometimes become evident at somewhat lower received levels, and
studies have shown that some species of baleen whales, notably bowhead,
gray, and humpback whales, at times, show strong avoidance at received
levels lower than 160 to 170 dB re 1 [mu]Pa (rms).
Researchers have studied the responses of humpback whales to
seismic surveys during migration, feeding during the summer months,
breeding while offshore from Angola, and wintering offshore from
Brazil. McCauley et al. (1998, 2000a) studied the responses of humpback
whales off western Australia to a full-scale seismic survey with a 16-
airgun array (2,678 in \3\) and to a single airgun (20 in\3\) with
source level of 227 dB re 1 [micro]Pa (p-p). In the 1998 study, they
documented that avoidance reactions began at 5 to 8 km (2.7 to 4.3 nmi)
from the array, and that those reactions kept most pods approximately 3
to 4 km (1.6 to 2.2 nmi) from the operating seismic boat. In the 2000
study, they noted localized displacement during migration of 4 to 5 km
(2.2 to 2.7 nmi) by traveling pods and 7 to 12 km (3.8 to 6.5 nmi) by
more sensitive resting pods of cow-calf pairs. Avoidance distances with
respect to the single airgun were smaller but consistent with the
results from the full array in terms of the received sound levels. The
mean received level for initial avoidance of an approaching airgun was
140 dB re 1 [mu]Pa (rms) for humpback pods containing females, and at
the mean closest point of approach distance from 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) (McCauley et al., 1998, 2000b).
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 in the
South Atlantic Ocean wintering off Brazil may be displaced or even
strand upon exposure to seismic surveys (Engel et al., 2004). The
evidence for this was circumstantial and subject to alternative
explanations (IAGC, 2004). Also, the evidence was not consistent with
subsequent results from the same area of Brazil (Parente et al., 2006),
or with direct studies of humpbacks exposed to seismic surveys in other
areas and seasons. After allowance for data from subsequent years,
there was ``no observable direct correlation'' between strandings and
seismic surveys (IWC, 2007: 236).
Reactions of migrating and feeding (but not wintering) gray whales
to seismic surveys have been studied. Malme et al. (1986, 1988) studied
the responses of feeding Eastern North Pacific gray whales to pulses
from a single 100 in\3\ airgun off St. Lawrence Island in the northern
Bering Sea. They estimated, based on small sample sizes, that 50
percent of feeding gray whales stopped feeding at an average received
pressure level of 173 dB re 1 [mu]Pa on an (approximate) rms basis, and
that 10 percent of feeding whales interrupted feeding at received
levels of 163 dB re 1 [micro]Pa (rms). Those findings were generally
consistent with the results of experiments conducted on larger numbers
of gray whales that were migrating along the California coast (Malme et
al., 1984; Malme and Miles, 1985), and Western North Pacific gray
whales feeding off Sakhalin Island, Russia (Wursig et al., 1999; Gailey
et al., 2007; Johnson et al., 2007; Yazvenko et al., 2007a, b), along
with data on gray whales off British Columbia (Bain and Williams,
2006).
Various species of Balaenoptera (blue, sei, fin, and minke whales)
have occasionally been seen in areas ensonified by airgun pulses
(Stone, 2003; MacLean and Haley, 2004; Stone and Tasker, 2006), and
calls from blue and fin whales have been localized in areas with airgun
operations (e.g., McDonald et al., 1995; Dunn and Hernandez, 2009;
Castellote et al., 2010). Sightings by observers on seismic vessels off
the United Kingdom from 1997 to 2000 suggest that, during times of good
sightability, sighting rates for mysticetes (mainly fin and sei whales)
were similar when large arrays of airguns were shooting vs. silent
(Stone, 2003; Stone and Tasker, 2006). However, these whales tended to
exhibit localized avoidance, remaining significantly further (on
average) from the airgun array during seismic operations compared with
non-seismic periods (Stone and Tasker, 2006). Castellote et al. (2010)
reported that singing fin whales in the Mediterranean moved away from
an operating airgun array.
Ship-based monitoring studies of baleen whales (including blue,
fin, sei, minke, and humpback whales) in the Northwest Atlantic found
that overall, this group had lower sighting rates during seismic vs.
non-seismic periods (Moulton and Holst, 2010). Baleen whales as a group
were also seen significantly farther from the vessel during seismic
compared with non-seismic periods, and they were more often seen to be
swimming away from the operating seismic vessel (Moulton and Holst,
2010). Blue and minke whales were initially sighted significantly
farther from the vessel during seismic operations compared to non-
seismic periods; the same trend was observed for fin whales (Moulton
and Holst, 2010). Minke whales were most often observed to be swimming
away from the vessel when seismic operations were underway (Moulton and
Holst, 2010).
Data on short-term reactions by cetaceans to impulsive noises are
not necessarily indicative of long-term or biologically significant
effects. It is not known whether impulsive sounds affect reproductive
rate or distribution and habitat use in subsequent days or years.
However, gray whales have continued to migrate annually along the west
coast of North America with substantial increases in the population
over recent years, despite intermittent seismic exploration (and much
ship traffic) in that area for decades (Appendix A in
[[Page 35653]]
Malme et al., 1984; Richardson et al., 1995; Allen and Angliss, 2010).
The Western North Pacific gray whale population did not seem affected
by a seismic survey in its feeding ground during a previous year
(Johnson et al., 2007). Similarly, bowhead whales have continued to
travel to the eastern Beaufort Sea each summer, and their numbers have
increased notably, despite seismic exploration in their summer and
autumn range for many years (Richardson et al., 1987; Allen and
Angliss, 2010). The history of coexistence between seismic surveys and
baleen whales suggests that brief exposures to sound pulses from any
single seismic survey are unlikely to result in prolonged effects.
Toothed Whales--There is little systematic information 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 Protected Species Observers (PSOs) on seismic
vessels regularly see dolphins and other small toothed whales near
operating airgun arrays, but in general there is a tendency for most
delphinids to show some avoidance of operating seismic vessels (e.g.,
Goold, 1996a,b,c; Calambokidis and Osmek, 1998; Stone, 2003; Moulton
and Miller, 2005; Holst et al., 2006; Stone and Tasker, 2006; Weir,
2008; Richardson et al., 2009; Barkaszi et al., 2009; Moulton and
Holst, 2010). Some dolphins seem to be attracted to the seismic vessel
and floats, and some ride the bow wave of the seismic vessel even when
large arrays of airguns are firing (e.g., Moulton and Miller, 2005).
Nonetheless, small toothed whales more often tend to head away, or to
maintain a somewhat greater distance from the vessel, when a large
array of airguns is operating than when it is silent (e.g., Stone and
Tasker, 2006; Weir, 2008; Barry et al., 2010; Moulton and Holst, 2010).
In most cases, the avoidance radii for delphinids appear to be small,
on the order of one km (0.5 nmi) or less, and some individuals show no
apparent avoidance. Based on observations from seismic surveys off the
United Kingdom, small odontocetes exhibited greater avoidance to
operating airguns than previously reported (Stone et al., 2003; Gordon
et al., 2004; Stone and Tasker, 2006). The observer data also indicated
that small odontocetes were feeding less and were interacting with the
vessel less during active seismic surveys. Captive bottlenose dolphins
and beluga whales (Delphinapterus leucas) exhibited changes in behavior
when exposed to strong pulsed sounds similar in duration to those
typically used in seismic surveys (Finneran et al., 2000, 2002, 2005).
However, the animals tolerated high, received levels of sound before
exhibiting aversive behaviors.
Results of reactions to seismic operations for porpoises depend on
species. The limited available data suggest that harbor porpoises 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). 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 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 are illusive and 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 definitively. 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 indications that some beaked whales may strand when naval
exercises involving mid-frequency sonar operation are ongoing nearby
(e.g., Simmonds and Lopez-Jurado, 1991; Frantzis, 1998; NOAA and USN,
2001; Jepson et al., 2003; Hildebrand, 2005; Barlow and Gisiner, 2006;
see also the ``Stranding and Mortality'' section in this notice). These
strandings are apparently a disturbance response, although auditory or
other injuries or other physiological effects may also be involved.
Whether beaked whales would ever react similarly to seismic surveys is
unknown. Seismic survey sounds are quite different from those of the
sonar in operation during the above-cited incidents.
Odontocete reactions to large arrays of airguns are variable and,
at least for delphinids and Dall's porpoises, seem to be confined to a
smaller radius than has been observed for the more responsive of some
mysticetes. However, other data suggest that some odontocete species,
including harbor porpoises, may be more responsive than might be
expected given their poor low-frequency hearing. Reactions at longer
distances may be particularly likely when sound propagation conditions
are conducive to transmission of the higher frequency components of
airgun sound to the animals' location (DeRuiter et al., 2006; Goold and
Coates, 2006; Tyack et al., 2006; Potter et al., 2007).
Pinnipeds--Information on the reaction of pinniped species to
pulsed seismic airgun sounds is limited. Based on early observations,
pinnipeds appear
[[Page 35654]]
to be quite tolerant of pulsed sounds. Other reports indicate that
pinnipeds were tolerant of loud, pulsed sounds when they were strongly
attracted to an area for feeding or reproductive purposes (Mate and
Harvey, 1987; Reeves et al., 1996). In most recent studies, avoidance
of pinnipeds during seismic surveys has been reported as being
relatively small, within 100 to few hundred meters. Many seals remained
within 100 to 200 m (328.1 to 656.2 ft) of the survey tracklines while
an operating seismic survey passed (Harris et al., 2001; Moulton and
Lawson, 2002). Other observations made during seismic surveys in the
Chukchi and Beaufort Seas reported that pinnipeds (i.e., ringed seals
[Phoca hispida]) were observed less when seismic airguns were operating
than when they were silent (Miller et al., 2005). In Puget Sound,
sighting distances for harbor seals 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 may be stronger than evident
to date from visual studies (Thompson et al., 1998). Overall,
behavioral reactions from pinnipeds to pulsed seismic sounds are
variable. It is expected that localized avoidance of operating seismic
airguns may occur; however, it cannot be guaranteed that these species
would fully avoid an operating seismic vessel during active surveys.
Hearing Impairment and Other Physical Effects
Exposure to high intensity sound for a sufficient duration may
result in auditory effects such as a noise-induced threshold shift--an
increase in the auditory threshold after exposure to noise (Finneran,
Carder, Schlundt, and Ridgway, 2005). Factors that influence the amount
of threshold shift include the amplitude, duration, frequency content,
temporal pattern, and energy distribution of noise exposure. The
magnitude of hearing threshold shift normally decreases over time
following cessation of the noise exposure. The amount of threshold
shift just after exposure is called the initial threshold shift. If the
threshold shift eventually returns to zero (i.e., the threshold returns
to the pre-exposure value), it is called temporary threshold shift
(TTS) (Southall et al., 2007).
Researchers have studied TTS in certain captive odontocetes and
pinnipeds exposed to strong sounds (reviewed in Southall et al., 2007).
However, there has been no specific documentation of TTS let alone
permanent hearing damage, i.e., permanent threshold shift (PTS), in
free-ranging marine mammals exposed to sequences of airgun pulses
during realistic field conditions.
Temporary Threshold Shift--TTS is the mildest form of hearing
impairment that can occur during exposure to a strong sound (Kryter,
1985). While experiencing TTS, the hearing threshold rises and a sound
must be stronger in order to be heard. At least in terrestrial mammals,
TTS can last from minutes or hours to (in cases of strong TTS) days.
For sound exposures at or somewhat above the TTS threshold, hearing
sensitivity in both terrestrial and marine mammals recovers rapidly
after exposure to the noise ends. Few data on sound levels and
durations necessary to elicit mild TTS have been obtained for marine
mammals, and none of the published data concern TTS elicited by
exposure to multiple pulses of sound. Available data on TTS in marine
mammals are summarized in Southall et al. (2007). Table 1 (above)
presents the estimated distances from the Langseth's airguns at which
the received energy level (per pulse, flat-weighted) would be expected
to be greater than or equal to 180 or 190 dB re 1 [micro]Pa (rms).
To avoid the potential for injury (i.e., Level A harassment), NMFS
(1995, 2000) concluded that cetaceans and pinnipeds should not be
exposed to pulsed underwater noise at received levels exceeding 180 and
190 dB re 1 [mu]Pa (rms), respectively. The established 180 and 190 dB
(rms) criteria are not considered to be the levels above which TTS
might occur. Rather, they are the received levels above which, in the
view of a panel of bioacoustics specialists convened by NMFS before TTS
measurements for marine mammals started to become available, one could
not be certain that there would be no injurious effects, auditory or
otherwise, to marine mammals. NMFS also assumes that cetaceans and
pinnipeds exposed to levels exceeding 160 dB re 1 [mu]Pa (rms) may
experience Level B harassment.
For toothed whales, researchers have derived TTS information for
odontocetes from studies on the bottlenose dolphin and beluga. The
experiments show that exposure to a single impulse at a received level
of 207 kPa (or 30 psi, p-p), which is equivalent to 228 dB re 1 Pa (p-
p), resulted in a 7 and 6 dB TTS in the beluga whale at 0.4 and 30 kHz,
respectively. Thresholds returned to within 2 dB of the pre-exposure
level within 4 minutes of the exposure (Finneran et al., 2002). For the
one harbor porpoise tested, the received level of airgun sound that
elicited onset of TTS was lower (Lucke et al., 2009). If these results
from a single animal are representative, it is inappropriate to assume
that onset of TTS occurs at similar received levels in all odontocetes
(cf. Southall et al., 2007). Some cetaceans apparently can incur TTS at
considerably lower sound exposures than are necessary to elicit TTS in
the beluga or bottlenose dolphin.
For baleen whales, there are no data, direct or indirect, on levels
or properties of sound that are required to induce TTS. The frequencies
to which baleen whales are most sensitive are assumed to be lower than
those to which odontocetes are most sensitive, and natural background
noise levels at those low frequencies tend to be higher. As a result,
auditory thresholds of baleen whales within their frequency band of
best hearing are believed to be higher (less sensitive) than are those
of odontocetes at their best frequencies (Clark and Ellison, 2004).
From this, it is suspected that received levels causing TTS onset may
also be higher in baleen whales than those of odontocetes (Southall et
al., 2007).
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
[[Page 35655]]
TTS threshold on a peak-pressure basis, and probably greater than 6 dB
(Southall et al., 2007).
Given the higher level of sound necessary to cause PTS as compared
with TTS, it is considerably less likely that PTS would occur. Baleen
whales generally avoid the immediate area around operating seismic
vessels, as do some other marine mammals. Some pinnipeds show avoidance
reactions to airguns, but their avoidance reactions are generally not
as strong or consistent as those of cetaceans, and occasionally they
seem to be attracted to operating seismic vessels (NMFS, 2010).
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.
Stranding and Mortality--When a living or dead marine mammal swims
or floats onto shore and becomes ``beached'' or incapable of returning
to sea, the event is termed a ``stranding'' (Geraci et al., 1999;
Perrin and Geraci, 2002; Geraci and Lounsbury, 2005; NMFS, 2007). The
legal definition for a stranding under the MMPA is that ``(A) a marine
mammal is dead and is (i) on a beach or shore of the United States; or
(ii) in waters under the jurisdiction of the United States (including
any navigable waters); or (B) a marine mammal is alive and is (i) on a
beach or shore of the United States and is unable to return to the
water; (ii) on a beach or shore of the United States and, although able
to return to the water is in need of apparent medical attention; or
(iii) in the waters under the jurisdiction of the United States
(including any navigable waters), but is unable to return to its
natural habitat under its own power or without assistance.''
Marine mammals are known to strand for a variety of reasons, such
as infectious agents, biotoxicosis, starvation, fishery interaction,
ship strike, unusual oceanographic or weather events, sound exposure,
or combinations of these stressors sustained concurrently or in series.
However, the cause or causes of most strandings are unknown (Geraci et
al., 1976; Eaton, 1979; Odell et al., 1980; Best, 1982). Numerous
studies suggest that the physiology, behavior, habitat relationships,
age, or condition of cetaceans may cause them to strand or might pre-
dispose them to strand when exposed to another phenomenon. These
suggestions are consistent with the conclusions of numerous other
studies that have demonstrated that combinations of dissimilar
stressors commonly combine to kill an animal or dramatically reduce its
fitness, even though one exposure without the other does not produce
the same result (Chroussos, 2000; Creel, 2005; DeVries et al., 2003;
Fair and Becker, 2000; Foley et al., 2001; Moberg, 2000; Relyea, 2005a,
2005b; Romero, 2004; Sih et al., 2004).
Strandings Associated with Military Active Sonar--Several sources
have published lists of mass stranding events of cetaceans in an
attempt to identify relationships between those stranding events and
military active sonar (Hildebrand, 2004; IWC, 2005; Taylor et al.,
2004). For example, based on a review of stranding records between 1960
and 1995, the International Whaling Commission (2005) identified ten
mass stranding events and concluded that, out of eight stranding events
reported from the mid-1980s to the summer of 2003, seven had been
coincident with the use of mid-frequency active sonar and most involved
beaked whales.
Over the past 12 years, there have been five stranding events
coincident with military mid-frequency active sonar use in which
exposure to sonar is believed to have been a contributing factor to
strandings: Greece (1996); the Bahamas (2000); Madeira (2000); Canary
Islands (2002); and Spain (2006). Refer to Cox et al. (2006) for a
summary of common features shared by the strandings events in Greece
(1996), Bahamas (2000), Madeira (2000), and Canary Islands (2002); and
Fernandez et al., (2005) for an additional summary of the Canary
Islands 2002 stranding event. USGS would not be using military sonars;
therefore, NMFS does not expect these potential effects to marine
mammals.
Potential for Stranding from Seismic Surveys--Marine mammals close
to underwater detonations of high explosives can be killed or severely
injured, and the auditory organs are especially susceptible to injury
(Ketten et al., 1993; Ketten, 1995). However, explosives are no longer
used in marine waters for commercial seismic surveys or (with rare
exceptions) for seismic research. These methods have been replaced
entirely by airguns or related non-explosive pulse generators. Airgun
pulses are less energetic and have slower rise times, and there is no
specific evidence that they can cause serious injury, death, or
stranding even in the case of large airgun arrays. However, the
association of strandings of beaked whales with naval exercises
involving mid-frequency active sonar (non-pulse sound) and, in one
case, the co-occurrence of an L-DEO seismic survey (Malakoff, 2002; Cox
et al., 2006), has raised the possibility that beaked whales exposed to
strong ``pulsed'' sounds could also be susceptible to injury and/or
behavioral reactions that can lead to stranding (e.g., Hildebrand,
2005; Southall et al., 2007).
Specific sound-related processes that lead to strandings and
mortality are not well documented, but may include:
(1) Swimming in avoidance of a sound into shallow water;
(2) A change in behavior (such as a change in diving behavior) that
might contribute to tissue damage, gas bubble formation, hypoxia,
cardiac arrhythmia, hypertensive hemorrhage or other forms of trauma;
(3) A physiological change such as a vestibular response leading to
a behavioral change or stress-induced hemorrhagic diathesis, leading in
turn to tissue damage; and
(4) Tissue damage directly from sound exposure, such as through
acoustically-mediated bubble formation and growth or acoustic resonance
of tissues.
Some of these mechanisms are unlikely to apply in the case of impulse
sounds. However, there are indications that gas-
[[Page 35656]]
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 area. The link
between the stranding and the seismic surveys was inconclusive and not
based on any physical evidence (Hogarth, 2002; Yoder, 2002).
Nonetheless, the Gulf of California incident plus the beaked whale
strandings near naval exercises involving use of mid-frequency sonar
suggests a need for caution in conducting seismic surveys in areas
occupied by beaked whales until more is known about effects of seismic
surveys on those species (Hildebrand, 2005). No injuries of beaked
whales are anticipated during the proposed study because of:
(1) The high likelihood that any beaked whales nearby would avoid
the approaching vessel before being exposed to high sound levels, and
(2) Differences between the sound sources operated by L-DEO and
those involved in the naval exercises associated with strandings.
Potential Effects of Other Acoustic Devices
Multi-Beam Echosounder
USGS 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 2 to 15 ms once every
5 to 20 s, depending on water depth. Most of the energy in the sound
pulses emitted by this multi-beam echosounder is at frequencies near 12
kHz, and the maximum source level is 242 dB re 1 [mu]Pa (rms). The beam
is narrow (1 to 2[deg]) in fore-aft extent and wide (150[deg]) in the
cross-track extent. Each ping consists of eight (in water greater than
1,000 m deep) or four (in water less than 1,000 m deep) successive fan-
shaped transmissions (segments) at different cross-track angles. Any
given mammal at depth near the trackline would be in the main beam for
only one or two of the nine segments. Also, marine mammals that
encounter the Kongsberg EM 122 are unlikely to be subjected to repeated
pulses because of the narrow fore-aft width of the beam and 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
versus more downward 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 USGS'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). They 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).
Masking--Marine mammal communications would not be masked
appreciably by the multi-beam echosounder signals given the low duty
cycle of the multi-beam 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) do
not overlap with the predominant frequencies in the calls, which would
avoid any significant masking.
Behavioral Responses--Behavioral reactions of free-ranging marine
mammals to sonars, echosounders, and
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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 acoustic Doppler current
profiler were transmitting during studies in the eastern tropical
Pacific, baleen whales showed no significant responses, while spotted
and spinner dolphins were detected slightly more often and beaked
whales less often during visual surveys (Gerrodette and Pettis, 2005).
Captive bottlenose dolphins and a beluga whale exhibited changes in
behavior when exposed to 1 s tonal signals at frequencies similar to
those that would be emitted by the multi-beam echosounder used by USGS,
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.
Hearing Impairment and Other Physical Effects--Given recent
stranding events that have been associated with the operation of naval
sonar, there is concern that mid-frequency sonar sounds can cause
serious impacts to marine mammals (see above). However, the multi-beam
echosounder proposed for use by USGS 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. 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 is not likely to result in the
harassment of marine mammals.
Sub-Bottom Profiler
USGS would also operate a sub-bottom profiler from the source
vessel during the proposed survey. Sounds from the sub-bottom profiler
are very short pulses, occurring for 1 to 4 ms once every few (3 to 6)
seconds. Most of the energy in the sound pulses emitted by the sub-
bottom profiler is at 3.5 kHz, and the beam is directed downward. The
sub-bottom profiler on the Langseth has a maximum source level of 204
dB re 1 [mu]Pa. Kremser et al. (2005) noted that the probability of a
cetacean swimming through the area of exposure when a bottom profiler
emits a pulse is small--even for a sub-bottom profiler more powerful
than that on the Langseth. If the animal was in the area, it would have
to pass the transducer at close range in order to be subjected to sound
levels that could cause TTS.
Masking--Marine mammal communications 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 most baleen whales,
the sub-bottom profiler signals do not overlap with the predominant
frequencies in the calls, which would avoid significant masking.
Behavioral Responses--Marine mammal behavioral reactions to other
pulsed sound sources are discussed above, and responses to the sub-
bottom profiler are likely to be similar to those for other pulsed
sources if received at the same levels. However, the pulsed signals
from the sub-bottom profiler are considerably weaker than those from
the 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 would 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.
Potential Effects of Vessel Movement and Collisions
Vessel movement in the vicinity of marine mammals has the potential
to result in either a behavioral response or a direct physical
interaction. Both scenarios are discussed below in this section.
Behavioral Responses to Vessel Movement--There are limited data
concerning marine mammal behavioral responses to vessel traffic and
vessel noise, and a lack of consensus among scientists with respect to
what these responses mean or whether they result in short-term or long-
term adverse effects. In those cases where there is a busy shipping
lane or where there is a large amount of vessel traffic, marine mammals
(especially low frequency specialists) may experience acoustic masking
(Hildebrand, 2005) if they are present in the area (e.g., killer whales
in Puget Sound; Foote et al., 2004; Holt et al., 2008). In cases where
vessels actively approach marine mammals (e.g., whale watching or
dolphin watching boats), scientists have documented that animals
exhibit altered behavior such as increased swimming speed, erratic
movement, and active avoidance behavior (Bursk, 1983; Acevedo, 1991;
Baker and MacGibbon, 1991; Trites and Bain, 2000; Williams et al.,
2002; Constantine et al., 2003), reduced blow interval (Ritcher et al.,
2003), disruption of normal social behaviors (Lusseau, 2003, 2006), and
the shift of behavioral activities which may increase energetic costs
(Constantine et al., 2003, 2004). A detailed review of marine mammal
reactions to ships and boats is available in Richardson et al., (1995).
For each of the marine mammal taxonomy groups, Richardson et al.,
(1995) provides the following assessment regarding reactions to vessel
traffic:
Toothed whales--``In summary, toothed whales sometimes show no
avoidance reaction to vessels, or even approach them. However,
avoidance can occur, especially in response to vessels of types used to
chase or hunt the animals. This may cause temporary displacement, but
we know of no clear evidence that toothed whales have abandoned
significant parts of their range because of vessel traffic.''
Baleen whales--``When baleen whales receive low-level sounds from
distant or stationary vessels, the sounds often seem to be ignored.
Some whales approach the sources of these sounds. When vessels approach
whales slowly and non-aggressively, whales often exhibit slow and
inconspicuous avoidance maneuvers. In response to
[[Page 35658]]
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 Langseth 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 Langseth's movements to result in Level B harassment.
Vessel Strike--Ship strikes of cetaceans can cause major wounds,
which may lead to the death of the animal. An animal at the surface
could be struck directly by a vessel, a surfacing animal could hit the
bottom of a vessel, or an animal just below the surface could be cut by
a vessel's propeller. The severity of injuries typically depends on the
size and speed of the vessel (Knowlton and Kraus, 2001; Laist et al.,
2001; Vanderlaan and Taggart, 2007).
The most vulnerable marine mammals are those that spend extended
periods of time at the surface in order to restore oxygen levels within
their tissues after deep dives (e.g., the sperm whale). In addition,
some baleen whales, such as the North Atlantic right whale, seem
generally unresponsive to vessel sound, making them more susceptible to
vessel collisions (Nowacek et al., 2004). These species are primarily
large, slow moving whales. Smaller marine mammals (e.g., bottlenose
dolphin) move quickly through the water column and are often seen
riding the bow wave of large ships. Marine mammal responses to vessels
may include avoidance and changes in dive pattern (NRC, 2003).
An examination of all known ship strikes from all shipping sources
(civilian and military) indicates vessel speed is a principal factor in
whether a vessel strike results in death (Knowlton and Kraus, 2001;
Laist et al., 2001; Jensen and Silber, 2003; Vanderlaan and Taggart,
2007). In assessing records in which vessel speed was known, Laist et
al. (2001) found a direct relationship between the occurrence of a
whale strike and the speed of the vessel involved in the collision. The
authors concluded that most deaths occurred when a vessel was traveling
in excess of 13 kts (24.1 km/hr, 14.9 mph).
USGS's proposed operation of one source vessel for the proposed
survey is relatively small in scale compared to the number of
commercial ships transiting at higher speeds in the same area on an
annual basis. The probability of vessel and marine mammal interactions
occurring during the proposed survey is unlikely due to the Langseth's
slow operational speed, which is typically 4.5 kts (8.5 km/hr, 5.3
mph). Outside of seismic operations, the Langseth's cruising speed
would be approximately 10 kts (18.5 km/hr, 11.5 mph), which is
generally below the speed at which studies have noted reported
increases of marine mammal injury or death (Laist et al., 2001).
As a final point, the Langseth has a number of other advantages for
avoiding ship strikes as compared to most commercial merchant vessels,
including the following: The Langseth's bridge offers good visibility
to visually monitor for marine mammal presence; Protected Species
Visual Observers (PSVO) posted during operations would scan the ocean
for marine mammals and would be required to report visual sightings of
marine mammal presence to crew; and the PSVOs receive extensive
training that covers the fundamentals of visual observing for marine
mammals and information about marine mammals and their identification
at sea. In addition, during airgun operations, a passive acoustic
monitoring (PAM) system would be deployed from the Langseth that may
alert the vessel of the presence of marine mammals in the vicinity of
the vessel.
Entanglement
Entanglement can occur if wildlife becomes immobilized in survey
lines, cables, nets, or other equipment that is moving through the
water column. The proposed seismic survey would require towing of
seismic equipment and cables. The large airgun array and hydrophone
streamer carries the risk of entanglement for marine mammals. Wildlife,
especially slow moving individuals, such as large whales, have a low
probability of becoming entangled due to the slow speed of the survey
vessel and onboard monitoring efforts. There are no recorded cases of
entanglement of marine mammals during the conduct of over 8 years of
seismic surveys on the Langseth. In May 2011, there was one recorded
entanglement of an olive ridley sea turtle (Lepidochelys olivacea) in
the Langseth's barovanes after the conclusion of a seismic survey off
Costa Rica. However, the barovanes would not be deployed from the
Langseth during USGS's proposed seismic survey. There have been cases
of baleen whales,
[[Page 35659]]
mostly gray whales (Heyning, 1990), becoming entangled in fishing
lines. The probability for entanglement of marine mammals is considered
not significant because of the vessel speed and the monitoring efforts
onboard the survey vessel.
The potential effects to marine mammals described in this section
of the document do not take into consideration the proposed monitoring
and mitigation measures described later in this document (see the
``Proposed Mitigation'' and ``Proposed Monitoring and Reporting''
sections) which, as noted, are designed to effect the least practicable
impact on affected marine mammal species and stocks.
Anticipated Effects on Marine Mammal Habitat
The proposed seismic survey is not anticipated to have any
permanent impact on habitats used by the marine mammals in the proposed
survey area, including the food sources they use (i.e., fish and
invertebrates). Additionally, no physical damage to any habitat is
anticipated as a result of conducting the proposed seismic survey.
While it is anticipated that the specified activity may result in
marine mammals avoiding certain areas due to temporary ensonification,
this impact to habitat is temporary and was considered in further
detail earlier in this document, as behavioral modification. The main
impact associated with the proposed activity would be temporarily
elevated noise levels and the associated direct effects on marine
mammals in any particular area of the proposed project area, previously
discussed in this notice. The proposed 2014 and 2015 seismic survey is
not operating in a small, defined location. During the proposed 3,165
km (1,709 nmi) and 3,115 km (1,682 nmi) of tracklines in 2014 and 2015,
respectively, the vessel would continuously move along the tracklines
during the survey. The next section discusses the potential impacts of
anthropogenic sound sources on common marine mammal prey in the
proposed survey area (i.e., fish and invertebrates).
Anticipated Effects on Fish
One reason for the adoption of airguns as the standard energy
source for marine seismic surveys is that, unlike explosives, they have
not been associated with large-scale fish kills. However, existing
information on the impacts of seismic surveys on marine fish and
invertebrate populations is limited. There are three types of potential
effects of exposure to seismic surveys: (1) Pathological, (2)
physiological, and (3) behavioral. Pathological effects involve lethal
and temporary or permanent sub-lethal injury. Physiological effects
involve temporary and permanent primary and secondary stress responses,
such as changes in levels of enzymes and proteins. Behavioral effects
refer to temporary and (if they occur) permanent changes in exhibited
behavior (e.g., startle and avoidance behavior). The three categories
are interrelated in complex ways. For example, it is possible that
certain physiological and behavioral changes could potentially lead to
an ultimate pathological effect on individuals (i.e., mortality).
The specific received sound levels at which permanent adverse
effects to fish potentially could occur are little studied and largely
unknown. Furthermore, the available information on the impacts of
seismic surveys on marine fish is from studies of individuals or
portions of a population; there have been no studies at the population
scale. The studies of individual fish have often been on caged fish
that were exposed to airgun pulses in situations not representative of
an actual seismic survey. Thus, available information provides limited
insight on possible real-world effects at the ocean or population
scale. This makes drawing conclusions about impacts on fish problematic
because, ultimately, the most important issues concern effects on
marine fish populations, their viability, and their availability to
fisheries.
Hastings and Popper (2005), Popper (2009), and Popper and Hastings
(2009a,b) provided recent critical reviews of the known effects of
sound on fish. The following sections provide a general synopsis of the
available information on the effects of exposure to seismic and other
anthropogenic sound as relevant to fish. The information comprises
results from scientific studies of varying degrees of rigor plus some
anecdotal information. Some of the data sources may have serious
shortcomings in methods, analysis, interpretation, and reproducibility
that must be considered when interpreting their results (see Hastings
and Popper, 2005). Potential adverse effects of the program's sound
sources on marine fish are noted.
Pathological Effects--The potential for pathological damage to
hearing structures in fish depends on the energy level of the received
sound and the physiology and hearing capability of the species in
question. For a given sound to result in hearing loss, the sound must
exceed, by some substantial amount, the hearing threshold of the fish
for that sound (Popper, 2005). The consequences of temporary or
permanent hearing loss in individual fish on a fish population are
unknown; however, they likely depend on the number of individuals
affected and whether critical behaviors involving sound (e.g., predator
avoidance, prey capture, orientation and navigation, reproduction,
etc.) are adversely affected.
Little is known about the mechanisms and characteristics of damage
to fish that may be inflicted by exposure to seismic survey sounds. Few
data have been presented in the peer-reviewed scientific literature. As
far as USGS and NMFS know, there are only two papers with proper
experimental methods, controls, and careful pathological investigation
implicating sounds produced by actual seismic survey airguns in causing
adverse anatomical effects. One such study indicated anatomical damage,
and the second indicated TTS in fish hearing. The anatomical case is
McCauley et al. (2003), who found that exposure to airgun sound caused
observable anatomical damage to the auditory maculae of pink snapper
(Pagrus auratus). This damage in the ears had not been repaired in fish
sacrificed and examined almost two months after exposure. On the other
hand, Popper et al. (2005) documented only TTS (as determined by
auditory brainstem response) in two of three fish species from the
Mackenzie River Delta. This study found that broad whitefish (Coregonus
nasus) exposed to five airgun shots were not significantly different
from those of controls. During both studies, the repetitive exposure to
sound was greater than would have occurred during a typical seismic
survey. However, the substantial low-frequency energy produced by the
airguns (less than 400 Hz in the study by McCauley et al. [2003] and
less than approximately 200 Hz in Popper et al. [2005]) likely did not
propagate to the fish because the water in the study areas was very
shallow (approximately nine m in the former case and less than two m in
the latter). Water depth sets a lower limit on the lowest sound
frequency that 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
[[Page 35660]]
chance of acute pathological effects increases. According to Buchanan
et al. (2004), for the types of seismic airguns and arrays involved
with the proposed program, the pathological (mortality) zone for fish
would be expected to be within a few meters of the seismic source.
Numerous other studies provide examples of no fish mortality upon
exposure to seismic sources (Falk and Lawrence, 1973; Holliday et al.,
1987; La Bella et al., 1996; Santulli et al., 1999; McCauley et al.,
2000a,b, 2003; Bjarti, 2002; Thomsen, 2002; Hassel et al., 2003; Popper
et al., 2005; Boeger et al., 2006).
An experiment of the effects of a single 700 in\3\ airgun was
conducted in Lake Meade, Nevada (USGS, 1999). The data were used in an
Environmental Assessment of the effects of a marine reflection survey
of the Lake Meade fault system by the National Park Service (Paulson et
al., 1993, in USGS, 1999). The airgun was suspended 3.5 m (11.5 ft)
above a school of threadfin shad in Lake Meade and was fired three
successive times at a 30 second interval. Neither surface inspection
nor diver observations of the water column and bottom found any dead
fish.
Some studies have reported, some equivocally, that mortality of
fish, fish eggs, or larvae can occur close to seismic sources
(Kostyuchenko, 1973; Dalen and Knutsen, 1986; Booman et al., 1996;
Dalen et al., 1996). Some of the reports claimed seismic effects from
treatments quite different from actual seismic survey sounds or even
reasonable surrogates. However, Payne et al. (2009) reported no
statistical differences in mortality/morbidity between control and
exposed groups of capelin eggs or monkfish larvae. Saetre and Ona
(1996) applied a `worst-case scenario' mathematical model to
investigate the effects of seismic energy on fish eggs and larvae. They
concluded that mortality rates caused by exposure to seismic surveys
are so low, as compared to natural mortality rates, that the impact of
seismic surveying on recruitment to a fish stock must be regarded as
insignificant.
Physiological Effects--Physiological effects refer to cellular and/
or biochemical responses of fish to acoustic stress. Such stress
potentially could affect fish populations by increasing mortality or
reducing reproductive success. Primary and secondary stress responses
of fish after exposure to seismic survey sound appear to be temporary
in all studies done to date (Sverdrup et al., 1994; Santulli et al.,
1999; McCauley et al., 2000a,b). The periods necessary for the
biochemical changes to return to normal are variable and depend on
numerous aspects of the biology of the species and of the sound
stimulus.
Behavioral Effects--Behavioral effects include changes in the
distribution, migration, mating, and catchability of fish populations.
Studies investigating the possible effects of sound (including seismic
survey sound) on fish behavior have been conducted on both uncaged and
caged individuals (e.g., Chapman and Hawkins, 1969; Pearson et al.,
1992; Santulli et al., 1999; Wardle et al., 2001; Hassel et al., 2003).
Typically, in these studies fish exhibited a sharp startle response at
the onset of a sound followed by habituation and a return to normal
behavior after the sound ceased.
The Minerals Management Service (MMS, 2005) assessed the effects of
a proposed seismic survey in Cook Inlet. The seismic survey proposed
using three vessels, each towing two, four-airgun arrays ranging from
1,500 to 2,500 in\3\. MMS noted that the impact to fish populations in
the survey area and adjacent waters would likely be very low and
temporary. MMS also concluded that seismic surveys may displace the
pelagic fishes from the area temporarily when airguns are in use.
However, fishes displaced and avoiding the airgun noise are likely to
backfill the survey area in minutes to hours after cessation of seismic
survey. 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 surveys 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 the NSF/USGS PEIS.
Pathological Effects--In water, lethal and sub-lethal injury to
organisms exposed to seismic survey sound appears to depend on at least
two features of the sound source: (1) The received peak pressure; and
(2) the time required for the pressure to rise and decay. Generally, as
received pressure increases, the period for the pressure to rise and
decay decreases, and the chance of acute pathological effects
increases. For the type of airgun array planned for the proposed
program, the pathological (mortality) zone for crustaceans and
cephalopods is expected to be within a few meters of the seismic
source, at most; however, very few specific data are available on
levels of seismic signals that might damage these animals. This premise
is based on the peak pressure and rise/decay time characteristics of
seismic airgun arrays currently in use around the world.
Some studies have suggested that seismic survey sound has a limited
pathological impact on early developmental stages of crustaceans
(Pearson et al., 1994; Christian et al., 2003; DFO, 2004). However, the
impacts appear to be either temporary or insignificant compared to what
occurs under natural conditions. Controlled
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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 [mu]Pa while captive in
relatively small tanks. They reported morphological and ultrastructural
evidence of massive acoustic trauma (i.e., permanent and substantial
alterations [lesions] of statocyst sensory hair cells) to the exposed
animals that increased in severity with time, suggesting that
cephalopods are particularly sensitive to low frequency sound. The
received SPL was reported as 157+/-5 dB re 1 [mu]Pa, with peak levels
at 175 dB re 1 [mu]Pa. As in the McCauley et al. (2003) paper on
sensory hair cell damage in pink snapper as a result of exposure to
seismic sound, the cephalopods were subjected to higher sound levels
than they would be under natural conditions, and they were unable to
swim away from the sound source.
Physiological Effects--Physiological effects refer mainly to
biochemical responses by marine invertebrates to acoustic stress. Such
stress potentially could affect invertebrate populations by increasing
mortality or reducing reproductive success. Primary and secondary
stress responses (i.e., changes in haemolymph levels of enzymes,
proteins, etc.) of crustaceans have been noted several days or months
after exposure to seismic survey sounds (Payne et al., 2007). It was
noted however, that no behavioral impacts were exhibited by crustaceans
(Christian et al., 2003, 2004; DFO, 2004). The periods necessary for
these biochemical changes to return to normal are variable and depend
on numerous aspects of the biology of the species and of the sound
stimulus.
Behavioral Effects--There is increasing interest in assessing the
possible direct and indirect effects of seismic and other sounds on
invertebrate behavior, particularly in relation to the consequences for
fisheries. Changes in behavior could potentially affect such aspects as
reproductive success, distribution, susceptibility to predation, and
catchability by fisheries. Studies investigating the possible
behavioral effects of exposure to seismic survey sound on crustaceans
and cephalopods have been conducted on both uncaged and caged animals.
In some cases, invertebrates exhibited startle responses (e.g., squid
in McCauley et al., 2000a,b). In other cases, no behavioral impacts
were noted (e.g., crustaceans in Christian et al., 2003, 2004; DFO
2004). There have been anecdotal reports of reduced catch rates of
shrimp shortly after exposure to seismic surveys; however, other
studies have not observed any significant changes in shrimp catch rate
(Andriguetto-Filho et al., 2005). Similarly, Parry and Gason (2006) did
not find any evidence that lobster catch rates were affected by seismic
surveys. Any adverse effects on crustacean and cephalopod behavior or
fisheries attributable to seismic survey sound depend on the species in
question and the nature of the fishery (season, duration, fishing
method).
Proposed Mitigation
In order to issue an Incidental Take Authorization (ITA) under
section 101(a)(5)(D) of the MMPA, NMFS must set forth the permissible
methods of taking pursuant to such activity, and other means of
effecting the least practicable impact on such species or stock and its
habitat, paying particular attention to rookeries, mating grounds, and
areas of similar significance, and the availability of such species or
stock for taking for certain subsistence uses (where relevant).
USGS has reviewed the following source documents and has
incorporated a suite of appropriate mitigation measures into their
project description.
(1) Protocols used during previous NSF and USGS-funded seismic
research cruises as approved by NMFS and detailed in the NSF/USGS PEIS;
(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 proposed activities, USGS and/or its designees have
proposed to implement the following mitigation measures for marine
mammals:
(1) Planning Phase;
(2) Proposed exclusion zones around the airgun(s);
(3) Power-down procedures;
(4) Shut-down procedures;
(5) Ramp-up procedures; and
(6) Special procedures for situations or species of concern.
Planning Phase--Mitigation of potential impacts from the proposed
activities began during the planning phases of the proposed activities.
USGS considered whether the research objectives could be met with a
smaller source than the full, 36-airgun array (6,600 in\3\) used on the
Langseth, and determined that the standard 36-airgun array with a total
volume of approximately 6,600 in\3\ was appropriate. USGS also worked
with L-DEO and NSF to identify potential time periods to carry out the
survey taking into consideration key factors such as environmental
conditions (i.e., the seasonal presence of marine mammals and other
protected species), weather conditions, equipment, and optimal timing
for other proposed seismic surveys using the Langseth. Most marine
mammal species are expected to occur in the study area year-round, so
altering the timing of the proposed project from spring and summer
months likely would result in no net benefits for those species.
Proposed Exclusion Zones--USGS use radii to designate exclusion and
buffer zones and to estimate take for marine mammals. Table 1
(presented earlier in this document) shows the distances at which one
would expect marine mammal exposures to received sound levels (160 and
180/190 dB) from the 36 airgun array and a single airgun. (The 180 dB
and 190 dB level shut-down criteria are applicable to cetaceans and
pinnipeds, respectively, as specified by NMFS [2000].) USGS used these
levels to establish the exclusion and buffer zones.
If the PSVO detects marine mammal(s) within or about to enter the
appropriate exclusion zone, the Langseth crew would immediately power-
down the airgun array, or perform a shut-down if necessary (see ``Shut-
down Procedures''). Table 1 summarizes the calculated distances at
which sound levels (160, 180 and 190 dB [rms]) are expected to be
received from the 36 airgun array and the single airgun operating in
deep water depths. Received sound levels have been calculated by USGS,
in relation to distance and direction from the airguns, for the 36
airgun array and for the single 1900LL 40 in\3\ airgun, which would be
used during power-downs.
Power-down Procedures--A power-down involves decreasing the number
of
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airguns in use to one airgun, such that the radius of the 180 dB or 190
dB zone is decreased to the extent that the observed marine mammal(s)
are no longer in or about to enter the exclusion zone for the full
airgun array. During a power-down for mitigation, L-DEO would operate
one small airgun. The continued operation of one airgun is intended to
(a) alert marine mammals to the presence of the seismic vessel in the
area; and (b) retain the option of initiating a ramp-up to full
operations under poor visibility conditions. In contrast, a shut-down
occurs when all airgun activity is suspended.
If the PSVO detects a marine mammal outside the exclusion zone that
is likely to enter the exclusion zone, USGS would power-down the
airguns to reduce the size of the 180 dB or 190 dB exclusion zone
before the animal is within the exclusion zone. Likewise, if a mammal
is already within the exclusion zone, when first detected USGS would
power-down the airguns immediately. During a power-down of the airgun
array, USGS would operate the single 40 in\3\ airgun, which has a
smaller exclusion zone. If the PSVO detects a marine mammal within or
near the smaller exclusion zone around that single airgun (see Table
1), USGS would shut-down the airgun (see next section).
Resuming Airgun Operations After a Power-down--Following a power-
down, the Langseth will not resume full airgun activity until the
marine mammal has cleared the 180 or 190 dB exclusion zone (see Table
1). The PSVO would consider the animal to have cleared the exclusion
zone if:
The PSVO has visually observed the animal leave the
exclusion zone, or
A PSVO has not sighted the animal within the exclusion
zone for 15 minutes for species with shorter dive durations (i.e.,
small odontocetes or pinnipeds), or 30 minutes for species with longer
dive durations (i.e., mysticetes and large odontocetes, including
sperm, pygmy sperm, dwarf sperm, and beaked whales); or
The vessel has transited outside the original 180 dB or
190 dB exclusion zone after a 10 minute wait period.
The Langseth crew would resume operating the airguns at full power
after 15 minutes of sighting any species with short dive durations
(i.e., small odontocetes or pinnipeds). Likewise, the crew would resume
airgun operations at full power after 30 minutes of sighting any
species with longer dive durations (i.e., mysticetes and large
odontocetes, including sperm, pygmy sperm, dwarf sperm, and beaked
whales).
Because the vessel would have transited away from the vicinity of
the original sighting during the 10 minute period, implementing ramp-up
procedures for the full array after an extended power-down (i.e.,
transiting for an additional 35 minutes from the location of initial
sighting) would not meaningfully increase the effectiveness of
observing marine mammals approaching or entering the exclusion zone for
the full source level and would not further minimize the potential for
take. The Langseth's PSVOs would continually monitoring the exclusion
zone for the full source level while the mitigation airgun is firing.
On average, PSVOs can observe to the horizon (10 km or 5.4 nmi) from
the height of the Langseth's observation deck and should be able to
state with a reasonable degree of confidence whether a marine mammal
would be encountered within this distance before resuming airgun
operations at full-power.
Shut-down Procedures--USGS would shut-down the operating airgun(s)
if a marine mammal is seen within or approaching the exclusion zone for
the single airgun. USGS would implement a shut-down:
(1) If an animal enters the exclusion zone of the single airgun
after USGS has initiated a power-down; or
(2) If an animal is initially seen within the exclusion zone of the
single airgun when more than one airgun (typically the full airgun
array) is operating (and it is not practical or adequate to reduce
exposure to less than 180 dB [rms] or 190 dB [rms]).
Considering the conservation status for the North Atlantic right
whale, the airguns would be shut-down immediately in the unlikely event
that this species is observed, regardless of the distance from the
Langseth. Ramp-up would only begin if the North Atlantic right whale
has not been seen for 30 minutes.
Resuming Airgun Operations After a Shut-down--Following a shut-down
in excess of 10 minutes, the Langseth crew would initiate a ramp-up
with the smallest airgun in the array (40 in\3\). The crew would turn
on additional airguns in a sequence such that the source level of the
array would increase in steps not exceeding 6 dB per five-minute period
over a total duration of approximately 30 minutes. During ramp-up, the
PSVOs would monitor the exclusion zone, and if they sight a marine
mammal, the Langseth crew would implement a power-down or shut-down as
though the full airgun array were operational.
During periods of active seismic operations, there are occasions
when the Langseth crew would need to temporarily shut-down the airguns
due to equipment failure or for maintenance. In this case, if the
airguns are inactive longer than eight minutes, the crew would follow
ramp-up procedures for a shut-down described earlier and the PSVOs
would monitor the full exclusion zone and would implement a power-down
or shut-down if necessary.
If the full exclusion zone is not visible to the PSVO for at least
30 minutes prior to the start of operations in either daylight or
nighttime, the Langseth crew would not commence ramp-up unless at least
one airgun (40 in\3\ or similar) has been operating during the
interruption of seismic survey operations. Given these provisions, it
is likely that the vessel's crew would not ramp-up the airgun array
from a complete shut-down at night or during poor visibility conditions
(i.e., in thick fog), because the outer part of the zone for that array
would not be visible during those conditions.
If one airgun has operated during a power-down period, ramp-up to
full power would be permissible 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. The vessel's crew would not initiate ramp-up of the airguns if a
marine mammal is sighted within or near the applicable exclusion zones.
Ramp-up Procedures--Ramp-up of an airgun array provides a gradual
increase in sound levels, and involves a step-wise increase in the
number and total volume of airguns firing until the full volume of the
airgun array is achieved. The purpose of a ramp-up is to ``warn''
marine mammals in the vicinity of the airguns, and to provide the time
for them to leave the area and thus avoid any potential injury or
impairment of their hearing abilities. USGS would follow a ramp-up
procedure when the airgun array begins operating after a 10 minute
period without airgun operations or when a power-down or shut-down has
exceeded that period. USGS and L-DEO have used similar periods
(approximately 8 to 10 minutes) during previous USGS and L-DEO seismic
surveys.
Ramp-up would begin with the smallest airgun in the array (40
in\3\). Airguns would be added in a sequence such that the source level
of the array would increase in steps not exceeding six dB per five
minute period over a total duration of approximately 30 to 35 minutes
(i.e., the time it takes to achieve full operation of the airgun
array). During ramp-up, the PSVOs would monitor the exclusion zone, and
if marine mammals are sighted, USGS would implement a power-down or
[[Page 35663]]
shut-down as though the full airgun array were operational.
If the complete exclusion zone has not been visible for at least 30
minutes prior to the start of operations in either daylight or
nighttime, USGS would not commence the ramp-up unless at least one
airgun (40 in\3\ or similar) has been operating during the interruption
of seismic survey operations. Given these provisions, it is likely that
the airgun array would not be ramped-up from a complete shut-down at
night or during poor visibility conditions (i.e., in thick fog),
because the outer part of the exclusion zone for that array would not
be visible during those conditions. If one airgun has operated during a
power-down period, ramp-up to full power would be permissible 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. USGS would not initiate a ramp-up of the
airguns if a marine mammal is sighted within or near the applicable
exclusion zones.
Use of a Small-Volume Airgun During Turns and Maintenance
For short-duration equipment maintenance activities, USGS would
employ the use of a small-volume airgun (i.e., 40 in\3\ ``mitigation
airgun'') to deter marine mammals from being within the immediate area
of the seismic operations. The mitigation airgun would be operated at
approximately one shot per minute and would not be operated for longer
than three hours in duration. The seismic survey's tracklines are
continuous around turns and no mitigation airgun would be necessary.
For longer-duration equipment maintenance or repair activities (greater
than three hours), USGS would shut-down the seismic equipment and not
involve using the mitigation airgun.
During brief transits (e.g., less than three hours), one mitigation
airgun would continue operating. The ramp-up procedure would still be
followed when increasing the source levels from one airgun to the full
airgun array. However, keeping one airgun firing would avoid the
prohibition of a ``cold start'' during darkness or other periods of
poor visibility. Through use of this approach, seismic operations may
resume without the 30 minute observation period of the full exclusion
zone required for a ``cold start,'' and without ramp-up if operating
with the mitigation airgun for under 10 minutes, or with ramp-up if
operating with the mitigation airgun over 10 minutes. PSOs would be on
duty whenever the airguns are firing during daylight, during the 30
minute periods prior to ramp-ups.
Special Procedures for Situations or Species of Concern--It is
unlikely that a North Atlantic right whale would be encountered during
the proposed seismic survey, but if so, the airguns would be shut-down
immediately if one is visually sighted at any distance from the vessel
because of its rarity and conservation status. The airgun array shall
not resume firing (with ramp-up) until 30 minutes after the last
documented North Atlantic right whale visual sighting. Concentrations
of humpback, sei, fin, blue, and/or sperm whales would be avoided if
possible (i.e., exposing concentrations of animals to 160 dB), and the
array would be powered-down if necessary. For purposes of this proposed
survey, a concentration or group of whales would consist of six or more
individuals visually sighted that do not appear to be traveling (e.g.,
feeding, socializing, etc.).
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 or minimization of injury or death of marine mammal
wherever possible (goals 2, 3, and 4 may contribute to this goal).
(2) A reduction in the numbers of marine mammals (total number of
number at biologically important time or location) exposed to received
levels of airgun operations, 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 times (total number or number at
biologically important time or location) individuals would be exposed
to received levels of airgun operations, 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 airgun operations, 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 of 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 ITAs
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. USGS 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
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public comment period or from the peer review panel.
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 seismic 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 receive level, distance from the source, and other
pertinent information);
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
USGS 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. USGS'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 region. USGS is prepared to
discuss coordination of its monitoring program with any related work
that might be done by other groups insofar as this is practical and
desirable.
Vessel-Based Visual Monitoring
PSVOs 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. PSVOs would
also watch for marine mammals near the seismic vessel for at least 30
minutes prior to the start of airgun operations after an extended shut-
down (i.e., greater than approximately 10 minutes for this proposed
cruise). When feasible, PSVOs 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
PSVO observations, the airguns would be powered-down or shut-down when
marine mammals are observed within or about to enter a designated
exclusion zone.
During seismic operations in the northwest Atlantic Ocean off the
Eastern Seaboard, at least five PSOs (four PSVOs and one Protected
Species Acoustic Observer [PSAO]) would be based aboard the Langseth.
USGS would appoint the PSOs with NMFS's concurrence. Observations would
take place during ongoing daytime operations and nighttime ramp-ups of
the airguns. During the majority of seismic operations, two PSVOs would
be on duty from the observation tower (i.e., the best available vantage
point on the source vessel) to monitor marine mammals near the seismic
vessel. Use of two simultaneous PSVOs would increase the effectiveness
of detecting animals near the source vessel. However, during meal times
and bathroom breaks, it is sometimes difficult to have two PSVOs on
effort, but at least one PSVO would be on duty. PSVO(s) would be on
duty in shifts no longer than 4 hours in duration.
Two PSVOs would also be on visual watch during all daytime ramp-ups
of the seismic airguns. A third PSAO would monitor the PAM equipment 24
hours a day to detect vocalizing marine mammals present in the action
area. In summary, a typical daytime cruise would have scheduled two
PSVOs on duty from the observation tower, and a third PSAO on PAM.
Other ship's crew would also be instructed to assist in detecting
marine mammals and implementing mitigation requirements (if practical).
Before the start of the seismic survey, the crew would be given
additional instruction on how to do so.
The Langseth is a suitable platform for marine mammal observations.
When stationed on the observation platform, the eye level would be
approximately 21.5 m (70.5 ft) above sea level, and the PSVO would have
a good view around the entire vessel. During daytime, the PSVO(s) would
scan the area around the vessel systematically with reticle binoculars
(e.g., 7 x 50 Fujinon), Big-eye binoculars (25 x 150), and with the
naked eye. During darkness or low-light conditions, night vision
devices (monoculars) and a forward looking infrared (FLIR) camera would
be available, when required. Laser range-finding binoculars (Leica LRF
1200 laser rangefinder or equivalent) would be available to assist with
distance estimation. Those are useful in training observers to estimate
distances visually, but are generally not useful in measuring distances
to animals directly; that is done primarily with the reticles in the
binoculars.
When marine mammals are detected within or about to enter the
designated exclusion zone, the airguns would immediately be powered-
down or shut-down if necessary. The PSVO(s) would continue to maintain
watch to determine when the animal(s) are outside the exclusion zone by
visual confirmation. Airgun operations would not resume until the
animal is confirmed to have left the exclusion zone, or if not observed
after 15 minutes for species with shorter dive durations (small
odontocetes and pinnipeds) or 30 minutes for species with longer dive
durations (mysticetes and large odontocetes, including sperm, pygmy
sperm, dwarf sperm, killer, and beaked whales).
Vessel-Based Passive Acoustic Monitoring
Vessel-based, towed PAM would complement the visual monitoring
program, when practicable. Visual monitoring typically is not effective
during periods of poor visibility or at night, and even with good
visibility, is unable to detect marine mammals when they are below the
surface or beyond visual range. PAM can be used in addition to visual
observations to improve detection, identification, and localization of
cetaceans. The PAM system would serve to alert visual observers (if on
duty) when vocalizing cetaceans are detected. It is only useful when
marine mammals call, but it does not depend on good visibility. It
would be monitored in real-time so that the PSVOs can be advised when
cetaceans are acoustically detected.
The PAM system consists of both hardware (i.e., hydrophones) and
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software (i.e., Pamguard). The ``wet end'' of the system consists of a
towed hydrophone array that is connected to the vessel by a tow cable.
The tow cable is 250 m (820.2 ft) long, and the hydrophones are fitted
in the last 10 m (32.8 ft) of cable. A depth gauge is attached to the
free end of the cable, and the cable is typically towed at depths 20 m
(65.6 ft) or less. The array would be deployed from a winch located on
the back deck. A deck cable would connect from the winch to the main
computer laboratory where the acoustic station, signal conditioning,
and processing system would be located. The acoustic signals received
by the hydrophones are amplified, digitized, and then processed by the
Pamguard software. The PAM system, which has a configuration of 4
hydrophones, can detect a frequency bandwidth of 10 Hz to 200 kHz.
One PSAO, an expert bioacoustician (in addition to the four PSVOs)
with primary responsibility for PAM, would be onboard the Langseth. The
expert bioacoustician would design and set up the PAM system and be
present to operate, oversee, and troubleshoot any technical problems
with the PAM system during the proposed survey. The towed hydrophones
would ideally be monitored by the PSAO 24 hours per day while within
the proposed seismic survey area during airgun operations, and during
most periods when the Langseth is underway while the airguns are not
operating. However, PAM may not be possible if damage occurs to the
array or back-up systems during operations. The primary PAM streamer on
the Langseth is a digital hydrophone streamer. Should the digital
streamer fail, back-up systems should include an analog spare streamer
and a hull-mounted hydrophone. One PSAO would monitor the acoustic
detection system by listening to the signals from two channels via
headphones and/or speakers and watching the real-time spectrographic
display for frequency ranges produced by cetaceans. The PSAO monitoring
the acoustical data would be on shift for no greater than six hours at
a time. All PSOs are expected to rotate through the PAM position,
although the expert PSAO (most experienced) would be on PAM duty more
frequently.
When a vocalization is detected while visual observations (during
daylight) are in progress, the PSAO would contact the PSVO immediately,
to alert him/her to the presence of cetaceans (if they have not already
been seen), and to allow a power-down or shut-down to be initiated, if
required. When bearings (primary and mirror-image) to calling
cetacean(s) are determined, the bearings would be relayed to the
PSVO(s) to help him/her sight the calling animal. During non-daylight
hours, when a cetacean is detected by acoustic monitoring and may be
close to the source vessel, the Langseth crew would be notified
immediately so that the proper mitigation measure may be implemented.
The information regarding the call would be entered into a
database. Data entry would include an acoustic encounter identification
number, whether it was linked with a visual sighting, date, time when
first and last heard and whenever any additional information was
recorded, position and water depth when first detected, bearing if
determinable, species or species group (e.g., unidentified dolphin,
sperm whale), types and nature of sounds heard (e.g., clicks,
continuous, sporadic, whistles, creaks, burst pulses, strength of
signal, etc.), and any other notable information. The acoustic
detection can also be recorded for further analysis.
PSO Data and Documentation
PSVOs 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 power-down or shut-down of the
airguns when a marine mammal is within or near the appropriate
exclusion zone. Observations would also be made during daytime periods
when the Langseth is underway without seismic operations. There would
also be opportunities to collect baseline biological data during the
transits to, from, and through the study area.
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 airguns or vessel (e.g., none, avoidance,
approach, paralleling, etc.), and behavioral pace.
2. Time, location, heading, speed, activity of the vessel, Beaufort
sea state and wind force, visibility, 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 and ramp-ups, power-downs, or shut-downs would be
recorded in a standardized format. The PSVOs would record this
information onto datasheets. During periods between watches and periods
when operations are suspended, those data would be entered into a
laptop computer running a custom electronic database. The accuracy of
the data entry would be verified by computerized data validity checks
as the data are entered and by subsequent manual checking of the
database. 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:
1. The basis for real-time mitigation (airgun power-down or shut-
down).
2. Information needed to estimate the number of marine mammals
potentially taken by harassment, which must be reported to NMFS.
3. Data on the occurrence, distribution, and activities of marine
mammals in the area where the seismic study is conducted.
4. Information to compare the distance and distribution of marine
mammals relative to the source vessel at times with and without seismic
activity.
5. Data on the behavior and movement patterns of marine mammals
seen at times with and without seismic activity.
Proposed Reporting
USGS would submit a comprehensive report to NMFS and NSF within 90
days after the end of phase 1 in 2014 and another comprehensive report
to NMFS and NSF within 90 days after the end of phase 2 in 2015 for the
proposed cruise. The report would describe the proposed operations that
were conducted and sightings of marine mammals within the vicinity of
the operations. The report would provide full documentation of methods,
results, and interpretation pertaining to all monitoring. The 90-day
report would summarize the dates and locations of seismic operations,
and all marine mammal sightings (i.e., dates, times, locations,
activities, associated seismic survey activities, and associated PAM
detections). The report would minimally include:
Summaries of monitoring effort--total hours, total
distances, and distribution of marine mammals through the study period
accounting for Beaufort sea state and wind force, and other factors
affecting visibility and detectability of marine mammals;
Analyses of the effects of various factors influencing
detectability of
[[Page 35666]]
marine mammals including Beaufort sea state and wind force, number of
PSOs, and fog/glare;
Species composition, occurrence, and distribution of
marine mammals sightings including date, water depth, numbers, age/
size/gender, and group sizes; and analyses of the effects of seismic
operations;
Sighting rates of marine mammals during periods with and
without airgun activities (and other variables that could affect
detectability);
Initial sighting distances versus airgun activity state;
Closest point of approach versus airgun activity state;
Observed behaviors and types of movements versus airgun
activity state;
Numbers of sightings/individuals seen versus airgun
activity state; and
Distribution around the source vessel versus airgun
activity state.
The report 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. After the report is considered final, it
would be publicly available on the NMFS, USGS and NSF Web sites at:
http://www.nmfs.noaa.gov/pr/permits/incidental.htm#iha, http://woodshole.er.usgs.gov/project-pages/environmental_compliance/index.html, and http://www.nsf.gov/geo/oce/encomp/index.jsp.
Notification of Injured or Dead Marine Mammals--In the
unanticipated event that the specified activity clearly causes the take
of a marine mammal in a manner not permitted by the authorization (if
issued), such as an injury, serious injury, or mortality (e.g., ship-
strike, gear interaction, and/or entanglement), the USGS shall
immediately cease the specified activities and immediately report the
incident to the Incidental Take Program Supervisor, Permits and
Conservation Division, Office of Protected Resources, NMFS, at 301-427-
8401 and/or by email to noaa.gov">Jolie.Harrison@noaa.gov and
noaa.gov">Howard.Goldstein@noaa.gov, the NMFS Greater Atlantic Region Marine
Mammal Stranding Network at 866-755-6622 (noaa.gov">Mendy.Garron@noaa.gov), and
the NMFS Southeast Region Marine Mammal Stranding Network at 877-433-
8299 (noaa.gov">Blair.Mase@noaa.gov and noaa.gov">Erin.Fougeres@noaa.gov). The report must
include the following information:
Time, date, and location (latitude/longitude) of the
incident;
Name and type of vessel involved;
Vessel's speed during and leading up to the incident;
Description of the incident;
Status of all sound source used 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 animal(s)
involved;
Fate of the animal(s); and
Photographs or video footage of the animal(s) (if
equipment is available).
USGS shall not resume its activities until NMFS is able to review
the circumstances of the prohibited take. NMFS shall work with USGS to
determine what is necessary to minimize the likelihood of further
prohibited take and ensure MMPA compliance. The USGS may not resume
their activities until notified by NMFS via letter, email, or
telephone.
In the event that USGS discovers an injured or dead marine mammal,
and the lead PSO determines that the cause of the injury or death is
unknown and the death is relatively recent (i.e., in less than a
moderate state of decomposition as NMFS describes in the next
paragraph), the USGS would immediately report the incident to the
Incidental Take Program Supervisor, Permits and Conservation Division,
Office of Protected Resources, at 301-427-8401 and/or by email to
noaa.gov">Jolie.Harrison@noaa.gov and noaa.gov">Howard.Goldstein@noaa.gov, the NMFS Greater
Atlantic Region Marine Mammal Stranding Network (866-755-6622) and/or
by email to the Greater Atlantic Regional Stranding Coordinator
(noaa.gov">Mendy.Garron@noaa.gov), and the NMFS Southeast Region Marine Mammal
Stranding Network (877-433-8299) and/or by email to the Southeast
Regional Stranding Coordinator (noaa.gov">Blair.Mase@noaa.gov) and Southeast
Regional Stranding Program Administrator (noaa.gov">Erin.Fougeres@noaa.gov). The
report must include the same information identified in the paragraph
above this section. Activities may continue while NMFS reviews the
circumstances of the incident. NMFS would work with the USGS to
determine whether modifications in the activities are appropriate.
In the event that USGS 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 authorized activities (e.g., previously wounded
animal, carcass with moderate to advanced decomposition, or scavenger
damage), the USGS would report the incident to the Incidental Take
Program Supervisor, Permits and Conservation Division, Office or
Protected Resources, at 301-427-8401 and/or by email to
noaa.gov">Jolie.Harrison@noaa.gov and noaa.gov">Howard.Goldstein@noaa.gov, the NMFS Greater
Atlantic Region Marine Mammal Stranding Network (866-755-6622), and/or
by email to the Greater Atlantic Regional Stranding Coordinator
(noaa.gov">Mendy.Garron@noaa.gov), and the NMFS Southeast Region Marine Mammal
Stranding Network (877-433-8299), and/or by email to the Southeast
Regional Stranding Coordinator (noaa.gov">Blair.Mase@noaa.gov) and Southeast
Regional Stranding Program Administrator (noaa.gov">Erin.Fougeres@noaa.gov),
within 24 hours of the discovery. The USGS would provide photographs or
video footage (if available) or other documentation of the stranded
animal sighting to NMFS and the Marine Mammal Stranding Network.
Activities may continue while NMFS reviews the circumstances of the
incident.
Estimated Take by Incidental Harassment
Except with respect to certain activities not pertinent here, the
MMPA defines ``harassment'' as: Any act of pursuit, torment, or
annoyance which (i) has the potential to injure a marine mammal or
marine mammal stock in the wild [Level A harassment]; or (ii) has the
potential to disturb a marine mammal or marine mammal stock in the wild
by causing disruption of behavioral patterns, including, but not
limited to, migration, breathing, nursing, breeding, feeding, or
sheltering [Level B harassment].
[[Page 35667]]
Table 3--NMFS's Current Underwater Acoustic Exposure Criteria
------------------------------------------------------------------------
Impulsive (non-explosive) sound
-------------------------------------------------------------------------
Criterion Criterion definition Threshold
------------------------------------------------------------------------
Level A harassment (injury). Permanent threshold 180 dB re 1
shift (PTS) (Any [micro]Pa-m (root
level above that means square [rms])
which is known to (cetaceans).
cause TTS). 190 dB re 1
[micro]Pa-m (rms)
(pinnipeds).
Level B harassment.......... Behavioral 160 dB re 1
disruption (for [micro]Pa-m (rms).
impulsive noise).
Level B harassment.......... Behavioral 120 dB re 1
disruption (for [micro]Pa-m (rms).
continuous noise).
------------------------------------------------------------------------
Level B harassment is anticipated and proposed to be authorized as
a result of the proposed marine seismic survey in the northwest
Atlantic Ocean off the Eastern Seaboard. Acoustic stimuli (i.e.,
increased underwater sound) generated during the operation of the
seismic airgun array are expected to result in the behavioral
disturbance of some marine mammals. There is no evidence that the
planned activities for which USGS seeks 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 USGS's methods to estimate take by
incidental harassment and present the applicant's and NMFS's estimates
of the numbers of marine mammals that could be affected during the
proposed seismic program in the northwest Atlantic Ocean. The estimates
are based on a consideration of the number of marine mammals that could
be harassed by seismic operations with the 36 airgun array to be used.
The length of the proposed 2D seismic survey area in 2014 is
approximately 3,165 km (1,704 nmi) and in 2015 is approximately 3,115
km (1,682 nmi) in the U.S. ECS region of the Eastern Seaboard in the
Atlantic Ocean, as depicted in Figure 1 of the IHA application. For
estimating take and other calculations, the 2015 tracklines are assumed
to be identical in length to the 2014 tracklines (even though they are
slightly shorter).
USGS assumes that, during simultaneous operations of the airgun
array and the other sources, any marine mammals close enough to be
affected by the multi-beam echosounder and sub-bottom profiler would
already be affected by the airguns. However, whether or not the airguns
are operating simultaneously with the other sources, marine mammals are
expected to exhibit no more than short-term and inconsequential
responses to the multi-beam echosounder and sub-bottom profiler given
their characteristics (e.g., narrow, downward-directed beam) and other
considerations described previously. Such reactions are not considered
to constitute ``taking'' (NMFS, 2001). Therefore, USGS provided no
additional allowance for animals that could be affected by sound
sources other than airguns.
Density estimates for marine mammals within the vicinity of the
proposed study area are limited. Density data for species found along
the East Coast of the U.S. generally extend slightly outside of the
U.S. EEZ. The proposed study area, however, is well beyond the U.S.
EEZ, and is well off the continental shelf break. The proposed survey
lines for the proposed 2014 survey are located in the far eastern
portion of the proposed study area, primarily within the area where
little to no density data are currently available. It was determined
that the best available information for density data (for those species
where density data existed) of species located off the U.S. East Coast
was housed at the Strategic Environmental and Development Program
(SERDP)/National Aeronautics and Space Administration (NASA)/NOAA
Marine Animal Model Mapper and OBIS-SEAMAP database. Within this
database, the model outputs for all four seasons from the U.S.
Department of the Navy Operating Area (OPAREA) Density Estimates (NODE)
for the Northeast OPAREA and Southeast OPAREA (Department of the Navy
2007a, 2007b) were used to determine the mean density (animals per
square kilometer) for 19 of the 38 marine mammals with the potential to
occur in the proposed study area. Those species include fin, minke,
Atlantic spotted, bottlenose, long-finned and short-finned pilot,
pantropical spotted, Risso's, short-beaked common, striped, sperm,
rough-toothed, dwarf and pygmy sperm, Sowerby's, Blainville's,
Gervais', True's, and Cuvier's beaked whales. Within the NODE document,
the density calculations and models both took into account detection
probability ([fnof][0]) and availability (g[0]) biases. Model outputs
for each season are available in the database. The data from the NODE
summer density models, which include the months of June, July, and
August, were used as the 2014 survey is proposed to take place between
late August and early September. Of the seasonal NODE density models
available, it is expected that the summer models are the most accurate
and robust as the survey data used to create all of the models were
obtained during summer months. The models for the winter, spring, and
fall are derived from the data collected during the summer surveys, and
therefore are expected to be less representative of actual species
density during those seasons.
For those species of marine mammals that did not have density model
outputs within the SERDP/NASA/NOAA and OBIS-SEAMAP database, or for
those species with density outputs that did not extend into the
proposed study area at all (i.e., all four pinniped species and sei
whale), but for which OBIS sightings data within or adjacent to the
proposed study area exist, the requested take authorization for the
mean group size of the species of marine mammal is included. The mean
group sizes were determined based on data reported from the Cetacean
and Turtle Assessment Program (CeTAP) surveys (CeTAP, 1982).
The estimated numbers of individuals potentially exposed to sound
during the proposed 2014 to 2015 survey are presented below and are
based on the 160 dB (rms) criterion currently used for all cetaceans
and pinnipeds. It is assumed that marine mammals exposed to airgun
sounds that strong could change their behavior sufficiently to be
considered ``taken by harassment.'' Table 4 shows the density estimates
calculated as described above and the estimates of the number of
different individual marine mammals that potentially could be exposed
to greater than or equal to 160 dB (rms) during the seismic survey if
no animals moved away from the survey vessel. The requested take
authorization is given in the middle (fourth from the left) column of
Table 4. For species for which densities were unavailable as described
above, but for which there were Ocean Biogeographic Information System
(OBIS) sightings within or adjacent to the proposed study area, USGS
has
[[Page 35668]]
included a requested take authorization for the mean group size for the
species.
It should be noted that unlike previous USGS, NSF, and L-DEO
seismic surveys aboard the Langseth, the proposed survey would be
conducted as almost one continuous line. Therefore, the ensonified area
for the proposed seismic survey does not include a contingency factor
(typically increased 25% to accommodate turns, lines that may need to
be repeated, equipment testing, etc.) in line-kilometers. As typical
during offshore ship surveys, inclement weather and equipment
malfunctions are likely to cause delays and may limit the number of
useful line-kilometers of seismic operations that can be undertaken.
Also, any marine mammal sightings within or near the designated
exclusion zones would result in a power-down and/or shut-down of
seismic operations as a mitigation measure. Thus, the following
estimates of the numbers of marine mammals potentially exposed to 160
dB (rms) sounds 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,
which is highly unlikely.
The number of different individuals that could be exposed to airgun
sounds with received levels greater than or equal to 160 dB (rms) on
one or more occasions can be estimated by considering the total marine
area that would be within the 160 dB (rms) radius around the operating
seismic source on at least one occasion, along with the expected
density of animals in the area. The number of possible exposures
(including repeated exposures of the same individuals) can be estimated
by considering the total marine area that would be within the 160 dB
radius around the operating airguns. In many seismic surveys, this
total marine area includes overlap, as seismic surveys are often
conducted in parallel survey lines where the ensonified areas of each
survey line would overlap. The proposed tracklines in 2014 and 2015
would not have overlap as the individual line segments do not run
parallel to each other. The entire survey could be considered one
continual survey line with slight turns (no more than 120 degrees)
between each line segment. During the proposed seismic survey, the
vessel would continue on the extensive survey line path, not staying
within a smaller defined area as most seismic surveys often do. The
numbers of different individuals potentially exposed to greater than or
equal to 160 dB (rms) were calculated by multiplying the expected
species density (for those marine mammal species that had density data
available) times the total anticipated area to be ensonified to that
level during airgun operations (3,165 km of survey lines). The total
area expected to be ensonified was determined by multiplying the total
trackline distance (3,165 km times the width of the swath of the 160 dB
buffer zone (2 times 5.78 km). Using this approach, a total of 36,600
km\2\ (10,671 nmi\2\) would fall within the 160 dB isopleth throughout
the proposed survey in 2014. The proposed survey in 2015 is expected to
ensonify an almost identical area (to within 2%); therefore, the same
ensonified area of 36,600 km\2\ (10,671 nmi\2\) was used for
calculation purposes since the number of estimated takes would be very
similar for each of the two years. The number of estimated takes for
the proposed survey in 2015 may need to be seasonally adjusted if the
activity takes place in the late spring or early summer. Because it is
uncertain at this time whether the 2015 survey would be scheduled in
the spring (March, April, and May) or summer (June, July, and August)
months, estimated takes were calculated for both seasons. For purposes
of conservatively estimating the number of takes, the higher density
(for spring or summer) was used for each species since it is not known
at this time which season the 2015 proposed survey would take place in
the April to August 2015 timeframe. If the 2015 survey occurred in the
spring rather than summer, the density data suggests that takes would
likely be higher for only the humpback whale, beaked whales, and
bottlenose dolphin, and takes would likely be fewer for nine species
(i.e., sperm whale, short-finned and long-finned pilot whales, Atlantic
spotted, pantropical spotted, striped, Clymene, short-beaked common,
and Risso's dolphin), and unchanged for the remaining species.
Table 4--Estimated Densities of Marine Mammal Species and Estimates of Possible Numbers of Marine Mammals Exposed to Sound Levels >=160 dB During USGS's
Proposed Seismic Survey in the Northwest Atlantic Ocean Off the Eastern Seaboard, August to September 2014 and April to August 2015
--------------------------------------------------------------------------------------------------------------------------------------------------------
Calculated take
authorization
2014/2015 [i.e., Approximate
Density spring/ estimated Requested take Abundance percentage of
summer (/km\2\) \1\ individuals (includes increase population/stock) regional Population trend \6\
exposed to to average group \4\ population/stock
sound levels size) \3\ (for requested
>=160 dB re 1 take) \5\
[mu]Pa] \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mysticetes:
North Atlantic right whale... NA 0/0 3 + 3 = 6........... 455/455............ 1.32/1.32 Increasing.
Humpback whale............... 0.0010170/0 0/38 38 + 3 = 41......... 11,600/823......... 0.35/4.98 Increasing.
Minke whale.................. 0.0000350/ 2/2 2 + 2 = 4........... 138,000/20,741..... 0.0014/0.0096 NA.
0.0000360
Bryde's whale................ NA 0/0 3 + 3 = 6........... NA/NA.............. NA/NA NA.
Sei whale.................... NA 0/0 3 + 3 = 6........... 10,300/357......... 0.06/1.68 NA.
Fin whale.................... 0.000060/ 3/3 3 + 3 = 6........... 26,500/3,522....... 0.02/0.17 NA.
0.000610
Blue whale................... NA 0/0 2 + 2 = 4........... 855/440............ 0.47/0.91 NA.
Odontocetes:
Sperm whale.................. 0.0019050/ 83/83 83 + 83 = 166....... 13,190/2,288....... 1.26/7.26 NA.
0.0022510
Pygmy sperm whale............ 0.0008850/ 33/33 33 + 33 = 66........ NA/3,785........... NA/1.74 NA.
0.008970
[[Page 35669]]
Dwarf sperm whale............ 0.0008850/ 33/33 33 + 33 = 66........ NA/3,785........... NA/1.74 NA.
0.0008970
Northern bottlenose whale.... NA 0/0 2 + 2 = 4........... 40,000/NA.......... 0.01/NA NA.
Cuvier's beaked whale........ 0.0021370/ 84/84 84 + 84 = 168....... NA/6,532........... NA/1.29 NA.
0.0022870
Mesoplodon spp. (i.e., ................ ................ .................... NA/7,092........... NA/2.37 NA.
True's, Gervais', Sowerby's,
and Blainville's beaked
whale.
Bottlenose dolphin........... 0.0069560/ 244/255 244 + 255 = 499..... NA/77,532.......... NA/0.64 NA.
0.0066470
Atlantic white-sided dolphin. NA 0/0 54 + 54 = 108....... 10,000 to 100,000s/ 1.08/0.22 NA.
48,819.
Fraser's dolphin............. NA 0/0 100 + 100 = 200..... NA/NA.............. NA/NA NA.
Atlantic spotted dolphin..... 0.0285700/ 1,056/1,056 1,056 + 1,056 = NA/44,715.......... NA/4.72 NA.
0.0288400 2,112.
Pantropical spotted dolphin.. 0.0194900/ 724/724 724 + 724 = 1,448... NA/3,333........... NA/43.44 NA.
0.0197600
Striped dolphin.............. 0.1330000/ 4,916/4,916 4,916 + 4,916 = NA/54,807.......... NA/17.94 NA.
0.1343000 9,832.
Spinner dolphin.............. NA 0/0 65 + 65 = 130....... NA/NA.............. NA/NA NA.
Clymene dolphin.............. 0.0093110/0 0/341 70 + 341 = 411...... NA/NA.............. NA/NA NA.
Short-beaked common dolphin.. 0.0053940/ 203/203 203 + 203 = 406..... NA/173,486......... NA/0.23 NA.
0.0055320
Rough-toothed dolphin........ 0.004200/ 16/16 16 + 16 = 32........ NA/271............. NA/11.81 NA.
0.0004260
Risso's dolphin.............. 0.0092150/ 342/342 342 + 342 = 684..... NA/18,250.......... NA/3.75 NA.
0.0093180
Melon-headed whale........... NA 0/0 100 + 100 = 200..... NA/NA.............. NA/NA NA.
Pygmy killer whale........... NA 0/0 25 + 25 = 50........ NA/NA.............. NA/NA NA.
False killer whale........... NA 0/0 15 + 15 = 30........ NA/NA.............. NA/NA NA.
Killer whale................. NA 0/0 7 + 7 = 14.......... NA/NA.............. NA/NA NA.
Short-finned pilot whale..... 0.0108000/ 697/697 697 + 697 = 1,394... 780,000/21,515..... 0.18/6.48 NA.
0.0190400
Long-finned pilot whale...... 0.0108000/ 697/697 697 + 697 = 1,394... 780,000/26,535..... 0.18/5.25 NA.
0.0190400
Harbor porpoise.............. NA 0/0 5 + 5 = 10.......... 500,000/79,883..... 0.002/0.01 NA.
Pinnipeds:
Harbor seal.................. NA 0/0 0 + 0 = 0........... NA/70,142.......... NA/NA NA.
Gray seal.................... NA 0/0 0 + 0 = 0........... NA/331,000......... NA/NA Increasing.
Harp seal.................... NA 0/0 0 + 0 = 0........... 8.6 to 9.6 million/ NA/NA NA.
7.1 million.
Hooded seal.................. NA 0/0 0 + 0 = 0........... 600,000/592,100.... NA/NA NA.
--------------------------------------------------------------------------------------------------------------------------------------------------------
NA = Not available or not assessed.
\1\ OBIS-SERDP-Navy NODE 2007a and 2007b (for those species where density data is available).
\2\ Calculated take is estimated density multiplied by the 160 dB ensonified area.
\3\ Requested take authorization was increased to group size for species for which densities were not available but that have been sighted near the
proposed survey area (CeTAP, 1984).
\4\ Stock sizes are best populations from NMFS Stock Assessment Reports where available (see Table 2 in above).
\5\ Requested takes expressed as percentages of the larger regional population and NMFS Stock Assessment Reports, where available.
\6\ Based on NMFS Stock Assessment Reports.
Applying the approach described above, approximately 36,600 km\2\
would be within the 160 dB isopleth on one or more occasions during the
proposed survey in 2014. The proposed survey in 2015 is expected to
ensonify an almost identical area (to within 2%); therefore an
ensonified area of 36,600 km\2\ was used for the proposed surveys in
2014
[[Page 35670]]
and 2015. Because this approach does not allow for turnover in the
marine mammal populations in the area during the course of the survey,
the actual number of individuals exposed may be underestimated,
although the conservative (i.e., probably overestimated) line-kilometer
distances used to calculate the area may offset this. Also, the
approach assumes that no cetaceans and pinnipeds would move away or
toward the trackline as the Langseth approaches in response to
increasing sound levels before the levels reach 160 dB (rms). Another
way of interpreting the estimates that follow is that they represent
the number of individuals that are expected (in the absence of a
seismic program) to occur in the waters that would be exposed to
greater than or equal to 160 dB (rms).
Encouraging and Coordinating Research
USGS would coordinate the planned marine mammal monitoring program
associated with the seismic survey with other parties that may have
interest in this area and specified activity. USGS would coordinate
with applicable U.S. agencies (e.g., NMFS), and would comply with their
requirements.
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 effect 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. 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.
Analyses 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.), 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, and effects on habitat.
In making a negligible impact determination, NMFS evaluated factors
such as:
(1) The number of anticipated injuries, serious injuries, or
mortalities;
(2) The number, nature, and intensity, and duration of Level B
harassment (all relatively limited); and
(3) The context in which the takes occur (i.e., impacts to areas of
significance, impacts to local populations, and cumulative impacts when
taking into account successive/contemporaneous actions when added to
baseline data);
(4) The status of stock or species of marine mammals (i.e.,
depleted, not depleted, decreasing, increasing, stable, impact relative
to the size of the population);
(5) Impacts on habitat affecting rates of recruitment/survival; and
(6) The effectiveness of monitoring and mitigation measures.
As described above and based on the following factors, the
specified activities associated with the marine seismic survey are not
likely to cause PTS, or other non-auditory injury, serious injury, or
death. The factors include:
(1) The likelihood that, given sufficient notice through relatively
slow ship speed, marine mammals are expected to move away from a noise
source that is annoying prior to its becoming potentially injurious;
(2) The 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 power-
down and shut-down measures); and
(4) The likelihood that marine mammal detection ability by trained
PSOs is high at close proximity to the vessel.
Table 4 of this document outlines the number of requested Level B
harassment takes that are anticipated as a result of these activities.
The type of Level B (behavioral) harassment that could result from the
proposed action are described in the ``Potential Effects of the
Specified Activity on Marine Mammals'' section above, and include
tolerance, masking, behavioral disturbance, TTS, PTS, and non-auditory
or physiological effects.
For the marine mammal species that may occur within the proposed
action area, there are no known designated or important feeding and/or
reproductive areas. Many animals perform vital functions, such as
feeding, resting, traveling, and socializing, on a diel cycle (i.e., 24
hr cycle). Behavioral reactions to noise exposure (such as disruption
of critical life functions, displacement, or avoidance of important
habitat) are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al., 2007). While
seismic operations are anticipated to occur on consecutive days, the
estimated duration of the survey would last no more than a total of 36
days (a 17 to 18 day leg in August to September 2014 and a 17 to 18 day
leg in April to August 2015). Additionally, the 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). The
seismic surveys would not take place in areas of significance for
marine mammal feeding, resting, breeding, or calving and would not
adversely impact marine mammal habitat. Furthermore, the vessel would
be constantly travelling over distances, and some animals may only be
exposed to and harassed by sound for less than a day.
NMFS's practice has been to apply the 160 dB re 1 [micro]Pa (rms)
received level threshold for underwater impulse sound levels to
determine whether take by Level B harassment occurs. Southall et al.
(2007) provide a severity scale for ranking observed behavioral
responses of both free-ranging marine mammals and laboratory subjects
to various types of anthropogenic sound (see Table 4 in Southall et al.
[2007]). NMFS has preliminarily determined, provided that the
aforementioned mitigation and monitoring measures are implemented, the
impact of conducting a marine seismic survey in the northwest Atlantic
Ocean off of the Eastern Seaboard, August to September 2014 and April
to August 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. No injuries, serious injuries, or
mortalities are anticipated to occur as a result of USGS's planned
marine seismic survey, and none are proposed to be authorized by NMFS.
[[Page 35671]]
While behavioral modifications, including temporarily vacating the
area during the operation of the airgun(s), may be made by these
species to avoid the resultant acoustic disturbance, the availability
of alternate areas within these areas for species and the short and
sporadic duration of the research activities, have led NMFS to
preliminary determine that the taking by Level B harassment from the
specified activity 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 activity is not expected to impact rates of annual
recruitment or survival for any affected species or stock, particularly
given the NMFS and the applicant's proposal to implement mitigation and
monitoring measures that 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 USGS's proposed marine seismic survey would have a
negligible impact on the affected marine mammal species or stocks.
Small Numbers
As mentioned previously, NMFS estimates that 34 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 are
provided in Table 4 of this document. No takes of pinnipeds are
expected due to a lack of species observations within the proposed
study area, the great distance offshore, and the deep water depths of
the proposed study area. It should be noted that the stock populations
for each marine mammal species in the NMFS Stock Assessment Reports are
generally for species populations in U.S. waters, which may
underestimate actual population sizes for species that have ranges that
would include waters outside the U.S. EEZ.
NMFS has regional population and/or stock abundance estimates for
the northwest Atlantic Ocean for 26 of the species under its
jurisdiction that could potentially be affected by Level B harassment
over the course of the IHA. The estimate of the number of individual
cetaceans by species for which NMFS has such data that could be exposed
to seismic sounds with received levels greater than or equal to 160 dB
re 1 [mu]Pa (rms) during the proposed survey in 2014 and 2015 is as
follows: 6 North Atlantic right, 41 humpback, 4 minke, 6 sei, 6 fin, 4
blue, and 166 sperm whales, which would represent 1.32/1.32, 0.353/
4.96, 0.0014/0.0096, 0.058/1.68, 0.02/0.17, 0.468/0.909, and 1.259/
7.255% of the affected regional populations/stocks, respectively. In
addition, 4 northern bottlenose, 168 Cuvier's and Mesoplodon (i.e.,
True's, Gervais', Sowerby's, and Blainville's beaked whales), 66 dwarf
sperm, and 66 pygmy sperm whales could be taken by Level B harassment
during the proposed seismic survey, which would represent 0.01/unknown,
unknown/1.286, unknown/2.369, unknown/1.744, and unknown/1.744% of the
regional populations/stocks, respectively. Most of the cetaceans
potentially taken by Level B harassment are delphinids; of the
delphinids for which NMFS has regional population or stock abundance
estimates for the northwest Atlantic Ocean, 499 bottlenose, 108
Atlantic white-sided, 2,112 Atlantic spotted, 1,448 pantropical
spotted, 9,832 striped, 406 short-beaked common, 32 rough-toothed, and
684 Risso's dolphins could be taken by Level B harassment during the
proposed seismic survey, which would represent unknown/0.644, 1.08/
0.221, unknown/4.723, unknown/43.444, unknown/17.939, unknown/0.234,
unknown/11.808, and unknown/3.748% of the regional populations/stocks,
respectively. Of the remaining species for which NMFS has regional
population or stock abundance estimates for the northwest Atlantic
Ocean, 1,394 short-finned and 1,394 long-finned pilot whales, and 10
harbor porpoises could be taken by Level B harassment during the
proposed seismic survey, which would represent 0.178/6.479, 0.178/
5.253, and 0.002/0.013% of the regional population/stocks,
respectively.
NMFS makes its small numbers determination on the numbers of marine
mammals that would be taken relative to the populations of the affected
species or stocks. NMFS calculates the number of animals as a
percentage of the stock population for marine mammals in the U.S. EEZ.
For USGS's proposed survey, approximately 80% in 2014 and 90% in 2015
of the tracklines occur within International Waters (i.e., the high
seas) and are outside of the U.S. EEZ; therefore, the regional
population is more applicable for NMFS's small numbers determinations
as most of the ensonified area and estimated takes are further than 200
nmi from the U.S. coastline. The requested take estimates represented
as a percentage of the stock in Table 4 (above) should be reduced to
20% and 10% of the calculated levels based on the amount of activity
(i.e., 80% and 90%) planned to occur outside of the U.S. EEZ in 2014
and 2015. Using the approach of calculating the number of requested
take estimates within the U.S. EEZ (20% in 2014 and 10% in 2015), the
take estimates provided in the preceding paragraph should change as
follows (rounding up): 2 North Atlantic right, 9 humpback, 2 minke, 2
sei, 2 fin, 2 blue, and 26 sperm whales, which would represent 0.44,
1.09, <0.01, 0.56, 0.06, 0.46, and 1.14% of the affected stocks,
respectively; 26 Cuvier's and Mesoplodon (i.e., True's, Gervais',
Sowerby's, and Blainville's beaked whales), 11 dwarf sperm, and 11
pygmy sperm whales, which would represent 0.4, 0.37, 0.29, and 0.29% of
the affected stocks, respectively; 75 bottlenose, 17 Atlantic white-
sided, 318 Atlantic spotted, 218 pantropical spotted, 1,476 striped, 62
short-beaked common, 6 rough-toothed, and 104 Risso's dolphins could be
taken by Level B harassment during the proposed seismic survey, which
would represent 0.1, 0.04, 0.71, 6.54, 2.69, 0.04, 2.21, and 0.57% of
the affected stocks, respectively; and 210 short-finned and 210 long-
finned pilot whales, and 2 harbor porpoises, which would represent
0.98, 0.79, and <0.01% of the affected stocks, respectively. No takes
of pinnipeds are expected within the proposed study area. The requested
take estimates represent a small number relative to the affected
species' with a known regional population or stock size (i.e., all for
which data are available are less than 6.54% of the regional
populations).
No known current regional population or stock abundance estimates
for the northwest Atlantic Ocean are available for the eight remaining
species under NMFS's jurisdiction that could potentially be affected by
Level B harassment over the course of the IHA. These species include
the Bryde's whale, Fraser's, spinner, and Clymene dolphins, and the
melon-headed, pygmy killer, false killer, and killer whales. Therefore,
NMFS is using older abundance estimates or abundance estimates from
other areas such as the northern Gulf of Mexico stock, regional ocean
basins (e.g., eastern tropical Pacific Ocean), or global summation to
aid its small numbers determination for these species. These
[[Page 35672]]
abundance estimates are considered the best available information.
Bryde's whales are distributed worldwide in tropical and sub-
tropical waters and their occurrence in the proposed study area is
rare. In the western North Atlantic Ocean, Bryde's whales are reported
from off the southeastern U.S. and southern West Indies to Cabo Frio,
Brazil (Leatherwood and Reeves, 1983). No stock of Bryde's whales has
been identified in U.S. waters off the Atlantic coast. The northern
Gulf of Mexico population is considered a separate stock and has a best
abundance estimate of 33 animals. In addition, there are estimated to
be 20,000 to 30,000 animals in the North Pacific Ocean. Based on all of
these factors, NMFS finds that the requested take estimate of 6 Bryde's
whales represents a small number relative to the affected species'
population size.
Fraser's dolphins are distributed worldwide in tropical waters and
their occurrence in the proposed study area is rare. There is no
abundance estimates for either the western North Atlantic or the
northern Gulf of Mexico stocks. The western North Atlantic population
is provisionally being considered a separate stock for management
purposes, although there is currently no information to differentiate
this stock from the northern Gulf of Mexico stock. The numbers of
Fraser's dolphins off the U.S. or Canadian Atlantic coast are unknown,
and seasonal abundance estimates are not available for this stock,
since it is rarely seen in any surveys. The population size for
Fraser's dolphins is unknown; however, about 289,000 animals occur in
the eastern tropical Pacific Ocean (Jefferson et al., 2008). The
estimated number of requested takes for 200 Fraser's dolphins
represents 0.06% of the eastern tropical Pacific Ocean population.
Fraser's dolphins are distributed worldwide in tropical waters and
their occurrence in the proposed study area is rare. Based on all these
factors, NMFS finds that the requested take estimate represents a small
number relative to the affected species' population size.
Spinner dolphins are found in all tropical and sub-tropical oceans
and their occurrence in the proposed study area is rare. The western
North Atlantic population of spinner dolphins is provisionally being
considered a separate stock for management purposes, although there is
currently no information to differentiate this stock from the northern
Gulf of Mexico stock. The numbers of spinner dolphins off the U.S. or
Canadian Atlantic coast are unknown, and seasonal abundance estimates
are not available for this stock since it was rarely seen in any of the
surveys. The best abundance estimate available for northern Gulf of
Mexico spinner dolphins is 11,441 animals. The estimated number of
requested takes of 130 spinner dolphins represents 1.13% of the
northern Gulf of Mexico stock. Based on all of these factors, NMFS
finds that the requested take estimates represents a small number
relative to the affected species' population size.
The Clymene dolphin is endemic to tropical and sub-tropical waters
of the Atlantic, including the Caribbean Sea and Gulf of Mexico
(Jefferson and Curry, 2003; Jefferson et al., 2008). This species
prefer warm waters and records extend from southern Brazil and Angola
and north to Mauritania and New Jersey off the U.S. east coast
(Jefferson et al., 2008). Their occurrence in the proposed study area
is rare. The abundance estimate for the Clymene dolphin in the western
North Atlantic was 6,086 in 203; this estimate is older than eight
years and is considered unreliable (Wade and Angliss, 1997; Mullin and
Fulling, 2003). However, this abundance estimate is the first and only
estimate to date for this species in the U.S. Atlantic EEZ and
represents the best abundance estimate. The estimated numbers of
requested takes of 411 Clymene dolphins represent 6.75% of the western
North Atlantic 2003 stock or 318.6% of the northern Gulf of Mexico
stock. Based on all of these factors, NMFS finds that the requested
take estimate represents a small number relative to the affected
species' population or stock size.
Melon-headed whales are distributed worldwide in tropical to sub-
tropical waters and their occurrence in the proposed study area is
rare. The western North Atlantic population is provisionally being
considered a separate stock from the northern Gulf of Mexico stock,
although there is currently no information to differentiate this stock
from the northern Gulf of Mexico stock. The numbers of melon-headed
whales off the U.S. or Canadian Atlantic coast are unknown, and
seasonal abundance estimates are not available for this stock, since it
was rarely seen in any surveys. The best abundance estimate available
for northern Gulf of Mexico melon-headed whales is 2,235 animals. The
estimated number of requested takes of 200 melon-headed whales
represents 8.94% of the northern Gulf of Mexico stock. Based on all of
these factors, NMFS finds that the requested take estimate represents a
small number relative to the affected species' population or stock
size.
The pygmy killer whale is distributed worldwide in tropical to sub-
tropical waters and their occurrence in the proposed study area is
rare. The western North Atlantic population of pygmy killer whales is
provisionally being considered one stock for management purposes. The
numbers of pygmy killer whales off the U.S. or Canadian Atlantic coast
are unknown, and seasonal abundance estimates are not available for
this stock, since it was rarely seen in any surveys. The best abundance
estimate available for the northern Gulf of Mexico pygmy killer whale
is 152 animals. In addition, there are estimated to be 39,000 pygmy
killer whales in the eastern tropical Pacific Ocean. The estimated
number of requested takes of 50 pygmy killer whales represents 32.89%
of the northern Gulf of Mexico stock, and 0.13% of the eastern tropical
Pacific Ocean. Based on all of these factors, NMFS finds that the
requested take estimate represents a small number relative to the
affected species' population or stock size.
The false killer whale is distributed worldwide throughout warm
temperate and tropical oceans and their occurrence in the proposed
study area is rare. No stock has been identified for false killer
whales in U.S. waters off the Atlantic coast. The Gulf of Mexico
population is provisionally being considered one stock for management
purposes, although there is currently no information to differentiate
this stock from the Atlantic Ocean stock. The current population size
for the false killer whale in the northern Gulf of Mexico is unknown
because they survey data is more than 8 years old; however, the most
recent abundance estimate pooled from 2004 to 2004 was 777 animals
(Wade and Angliss, 1997; Mullin, 2007). The estimated number of
requested takes of 30 false killer whales represents 3.86% of the
northern Gulf of Mexico stock. Based on all of these factors, NMFS
finds that the requested take estimate represents a small number
relative to the affected species' population or stock size.
Killer whales are characterized as uncommon or rare in waters of
the U.S. Atlantic EEZ (Katona et al., 1988). Their distribution extends
from the Arctic ice-edge to the West Indies, often in offshore and mid-
ocean areas. There are estimated to be at least approximately 92,500
killer whales worldwide. The size of the western North Atlantic stock
population off the eastern U.S. coast is unknown. The northern Gulf of
Mexico population is provisionally being considered a separate stock
for management purposes, although there is currently no information to
differentiate
[[Page 35673]]
this stock from the Atlantic Ocean stock. The best abundance estimate
available for northern Gulf of Mexico killer whales is 28 animals. The
estimated number of requested takes of 14 killer whales represents
0.02% of the worldwide population, and 50% of the northern Gulf of
Mexico stock. Based on all of these factors, NMFS finds that the
requested take estimate represents a small number relative to the
affected species' population or stock size.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration of the implementation of the mitigation and monitoring
measures, NMFS preliminarily finds that small numbers of marine mammals
would be taken relative to the populations of the affected species or
stocks. See Table 4 for the requested authorized take number of marine
mammals.
Endangered Species Act
Of the species of marine mammals that may occur in the proposed
survey area, several are listed as endangered under the ESA, including
the North Atlantic right, humpback, sei, fin, blue, and sperm whales.
Under section 7 of the ESA, USGS has initiated formal consultation with
the NMFS, Office of Protected Resources, Endangered Species Act
Interagency Cooperation Division, on this proposed seismic survey.
NMFS's Office of Protected Resources, Permits and Conservation
Division, has initiated formal consultation under section 7 of the ESA
with NMFS's Office of Protected Resources, Endangered Species Act
Interagency Cooperation Division, to obtain a Biological Opinion
evaluating the effects of issuing the IHA on threatened and endangered
marine mammals and, if appropriate, authorizing incidental take. NMFS
would conclude formal section 7 consultation prior to making a
determination on whether or not to issue the IHA. If the IHA is issued,
USGS, in addition to the mitigation and monitoring requirements
included in the IHA, would be required to comply with the Terms and
Conditions of the Incidental Take Statement corresponding to NMFS's
Biological Opinion issued to both USGS and NMFS's Office of Protected
Resources.
National Environmental Policy Act
With USGS's complete application, USGS provided NMFS a ``Draft
Environmental Assessment for Seismic Reflection Scientific Research
Surveys During 2014 and 2015 in Support of Mapping the U.S. Atlantic
Seaboard Extended Continental Margin and Investigating Tsunami
Hazards,'' prepared by RPS Evan-Hamilton, Inc., in association with
YOLO Environmental, Inc., GeoSpatial Strategy Group, and Ecology and
Environment, Inc., on behalf of USGS. The EA analyzes the direct,
indirect, and cumulative environmental impacts of the proposed
specified activities on marine mammals including those listed as
threatened or endangered under the ESA. Prior to making a final
decision on the IHA application, NMFS would either prepare an
independent EA, or, after review and evaluation of the USGS EA for
consistency with the regulations published by the Council of
Environmental Quality (CEQ) and NOAA Administrative Order 216-6,
Environmental Review Procedures for Implementing the National
Environmental Policy Act, adopt the EA and make a decision of whether
or not to issue a Finding of No Significant Impact (FONSI).
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to USGS for conducting the high-energy marine seismic
survey in the northeast Atlantic Ocean off the Eastern Seaboard,
provided the previously mentioned mitigation, monitoring, and reporting
requirements are incorporated. The proposed IHA language is provided
below:
The NMFS hereby authorizes the U.S. Geological Survey, Pacific
Coastal and Marine Geology Science Center, Mail Stop 999, 345
Middlefield Road, Menlo Park, California 94025, Lamont-Doherty Earth
Observatory of Columbia University, P.O. Box 1000, 61 Route 9W,
Palisades, New York 10964-8000, and National Science Foundation,
Division of Ocean Sciences, 4201 Wilson Boulevard, Suite 725,
Arlington, Virginia 22230 (herein referred to USGS) 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 high-energy marine geophysical (seismic) survey conducted by the R/V
Marcus G. Langseth (Langseth) in the northeast Atlantic Ocean off the
Eastern Seaboard, August to September 2014 and April to August 2015:
1. This Authorization is valid from August 15, 2014 through August
14, 2015.
2. This Authorization is valid only for the Langseth's specified
activities associated with seismic survey operations as described in
USGS's IHA application and ``Draft Environmental Assessment for Seismic
Reflection Scientific Surveys During 2014 and 2015 in Support of
Mapping the U.S. Atlantic Seaboard Extended Continental Margin and
Investigating Tsunami Hazards'' that shall occur in the following
specified geographic area (bounded by the following geographical
coordinates):
40.5694[deg] North, -66.5324[deg] West;
38.5808[deg] North, -61.7105[deg] West;
29.2456[deg] North, -72.6766[deg] West;
33.1752[deg] North, -75.8697[deg] West;
39.1583[deg] North, -72.8697[deg] West;
The proposed activities for 2014 will generally occur within the
outer portions of the study area. The proposed activities for 2015 will
in-fill more of the study area. Water depths range from approximately
1,450 to 5,400 m (see Figure 1 and 2 of the IHA application); no survey
lines will extend to water depths less than 1,000 m. The tracklines
proposed for both 2014 and 2015 would be in International Waters
(approximately 80% in 2014 and 90% in 2015) and in the U.S. EEZ, as
specified in USGS's Incidental Harassment Authorization application and
the associated USGS Environmental Assessment.
3. Species Authorized and Level of Takes
(a) The incidental taking of marine mammals, by Level B harassment
only, is limited to the following species in the waters of the
northeast Atlantic off the Eastern Seaboard:
(i) Mysticetes--see Table 4 for authorized species and take
numbers.
(ii) Odontocetes--see Table 4 for authorized species and take
numbers.
(iii) If any marine mammal species are encountered during seismic
activities that are not listed in Table 4 for authorized taking and are
likely to be exposed to sound pressure levels (SPLs) greater than or
equal to 160 dB re 1 [mu]Pa (rms), then the USGS must alter speed or
course or shut-down the airguns to avoid take.
(b) The taking by injury (Level A harassment), serious injury, or
death of any of the species listed in Condition 3(a) above or the
taking of any kind of any other species of marine mammal is prohibited
and may result in the modification, suspension or revocation of this
Authorization.
4. The methods authorized for taking by Level B harassment are
limited to the following acoustic sources without an amendment to this
Authorization:
(a) A 36 airgun array with a total volume of 6,600 cubic inches (in
\3\) (or smaller);
(b) A multi-beam echosounder; and
(c) A sub-bottom profiler.
[[Page 35674]]
5. The taking of any marine mammal in a manner prohibited under
this Authorization must be reported immediately to the Office of
Protected Resources, National Marine Fisheries Service (NMFS), at 301-
427-8401 and/or by email to noaa.gov">Jolie.Harrison@noaa.gov and
noaa.gov">Howard.Goldstein@noaa.gov.
6. Mitigation and Monitoring Requirements
The USGS is required to implement the following mitigation and
monitoring requirements when conducting the specified activities to
achieve the least practicable impact on affected marine mammal species
or stocks:
(a) Utilize two, NMFS-qualified, vessel-based PSVO (except during
meal times and restroom breaks, when at least one PSVO shall be on
watch) to visually watch for and monitor marine mammals near the
seismic source vessel during daytime airgun operations (from nautical
twilight-dawn to nautical twilight-dusk) and before and during ramp-ups
of airguns day or night.
(i) The Langseth's vessel crew shall also assist in detecting
marine mammals, when practicable.
(ii) PSVOs shall have access to reticle binoculars (7 x 50
Fujinon), big-eye binoculars (25 x 150), optical range finders, and
night vision devices.
(iii) PSVO shifts shall last no longer than 4 hours at a time.
(iv) When feasible, PSVOs shall also make observations during
daytime periods when the seismic system is not operating for comparison
of animal abundance and behavioral reactions during, between, and after
airgun operations.
(v) PSVOs shall conduct monitoring while the airgun array and
streamer(s) are being deployed or recovered from the water.
(b) PSVOs 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 6(c)(ii) shall also be
recorded at the start and end of each observation watch and during a
watch whenever there is a change in one or more of the variables.
Passive Acoustic Monitoring
(c) Utilize the PAM system, to the maximum extent practicable, to
detect and allow some localization of marine mammals around the
Langseth during all airgun operations and during most periods when
airguns are not operating. One NMFS-qualified PSO and/or expert
bioacoustician (i.e., PSAO) shall monitor the PAM at all times in
shifts no longer than 6 hours. An expert bioacoustician shall design
and set up the PAM system and be present to operate to oversee PAM, and
available when technical issues occur during the survey.
(d) Do and record the following when an animal is detected by the
PAM:
(i) Notify the on-duty PSVO(s) immediately of the presence of a
vocalizing marine mammal so a power-down or shut-down can be initiated,
if required:
(ii) Enter the information regarding the vocalization into a
database. The data to be entered include an acoustic encounter
identification number, whether it was linked with a visual sighting,
date, time when first and last heard and whenever any additional
information was recorded, position, and water depth when first
detected, bearing if determinable, species or species group (e.g.,
unidentified dolphin, sperm whale), types and nature of sounds heard
(e.g., clicks, continuous, sporadic, whistles, creaks, burst pulses,
strength of signal, etc.), and any other notable information. The
acoustic detection can also be recorded for further analysis.
Buffer and Exclusion Zones
(e) Establish a 160 dB re 1 [micro]Pa (rms) buffer zone as well as
180 and 190 dB re 1 [micro]Pa (rms) exclusion zone for marine mammals
before the 2-string airgun array (6,600 in\3\) is in operation; and a
180 and 190 dB re 1 [micro]Pa (rms) exclusion zone before a single
airgun (40 in\3\) is in operation, respectively. See Table 1 (above)
for distances and exclusion zones.
Visual Monitoring at the Start of Airgun Operations
(f) Visually observe the entire extent of the exclusion zone (180
dB re 1 [mu]Pa [rms] for cetaceans; see Table 1 [above] for distances)
using NMFS-qualified PSVOs, for at least 30 minutes prior to starting
the airgun array (day or night).
(i) If the PSVO observes a marine mammal within the exclusion zone,
USGS must delay the seismic survey until the marine mammal(s) has left
the area. If the PSVO sees a marine mammal that surfaces, then dives
below the surface, the PSVO shall wait 30 minutes. If the PSVO sees no
marine mammals during that time, he/she 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 within the exclusion zone, the
airguns may not resume airgun operations.
(iii) If one airgun is already running at a source level of at
least 180 dB re 1 [mu]Pa (rms), USGS may start the second airgun, and
subsequent airguns, without observing the entire exclusion zone for 30
minutes prior, provided no marine mammals are known to be near the
exclusion zone (in accordance with Condition 6[h] below).
Ramp-Up Procedures
(g) Ramp-up procedures at the start of seismic operations or after
a shut-down--Implement a ``ramp-up'' procedure when starting-up at the
beginning of seismic operations or any time after the entire array has
been shut-down for more than 10 minutes, which means starting with the
smallest airgun first and adding airguns in a sequence such that the
source level of the array shall increase in steps not exceeding
approximately 6 dB per 5-minute period. During ramp-up, the PSVOs shall
monitor the 180 and 190 dB exclusion zone for cetaceans and pinnipeds,
respectively, and if marine mammals are sighted within or about to
enter the relevant exclusion zone, a power-down, or shut-down shall be
implemented as though the full array were operational. Therefore,
initiation of ramp-up procedures from a shut-down or at the beginning
of seismic operations requires that the PSVOs be able to view the full
exclusion zone as described in Condition 6(m) (below).
Power-Down Procedures
(h) Power-down the airgun(s) if a marine mammal is detected within,
approaches, or enters the relevant exclusion zone (as defined in Table
1, above). A power-down means reducing the number of operating airguns
to a single operating 40 in\3\ airgun, which reduces the exclusion zone
to the degree that the animal(s) is no longer in or about to enter it
for the full airgun array. When appropriate or possible, power-down of
the airgun array shall also occur when the vessel is moving from the
end of one trackline to the start of the next trackline.
(i) Following a power-down, if the marine mammal approaches the
small
[[Page 35675]]
designated exclusion zone, the airguns must then be completely shut-
down. Airgun activity shall not resume until the PSVO has visually
observed the marine mammal(s) exiting the exclusion zone and is not
likely to return, or has not been seen within the exclusion zone for 15
minutes for species with shorter dive durations (small odontocetes) or
30 minutes for species with longer dive durations (mysticetes and large
odontocetes, including sperm, pygmy sperm, dwarf sperm, killer, and
beaked whales).
(j) Following a power-down and subsequent animal departure, the
airgun operations may resume at full power. Initiation requires that
PSVOs can effectively monitor the full exclusion zones described
Condition 6(g). If the PSVO(s) sees a marine mammal within or about to
enter the relevant zones, when a course/speed alteration, power-down,
or shut-down will be implemented.
Shut-Down Procedures
(k) Shut-down the airgun(s) if a marine mammal is detected within,
approaches, or enters the relevant exclusion zone (as defined in Table
1, above). A shut-down means all operating airguns are shut-down (i.e.,
turned off).
(l) Following a shut-down, if the PSVO has visually confirmed that
the animal has departed the relevant exclusion zone (and is not likely
to return) within a period less than or equal to 10 minutes after the
shut-down, the airgun operations may resume at full power. If the PSVO
has not observed the marine mammal(s) exiting the exclusion zone, the
airgun operations shall not resume for 15 minutes for species with
shorter dive durations (small odontocetes) or 30 minutes for species
with longer dive durations (mysticetes and large odontocetes, including
sperm, pygmy sperm, dwarf sperm, killer, and beaked whales). Following
a shut-down, the Langseth may resume following ramp-up procedures
described in Condition 6(h).
Speed or Course Alteration
(m) 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 power-down or shut-down, shall be taken.
Survey Operations at Night
(n) Marine seismic surveys may continue into night and low-light
hours if such segment(s) of the survey is initiated when the entire
relevant exclusion zones are visible and can be effectively monitored.
(o) No initiation of airgun array operations is permitted from a
shut-down position at night or during low-light hours (such as in dense
fog or heavy rain) when the entire relevant exclusion zone cannot be
effectively monitored by the PSO(s) on duty.
Mitigation Airgun
(p) Use of small-volume airgun (i.e., mitigation airgun) during
turns and maintenance shall be operated at approximately one shot per
minute and would not be operated for longer than three hours in
duration. During turns or brief transits between seismic tracklines,
one airgun will continue operating.
Special Procedures for Situations or Species of Concern
(q) If a North Atlantic right whale (Eubalaena glacialis) is
visually sighted, the airgun array shall be shut-down regardless of the
distance of the animal(s) to the sound source. The array shall not
resume firing until 30 minutes after the last documented whale visual
sighting.
(r) Concentrations of humpback (Megaptera novaeangliae), sei
(Balaenoptera borealis), fin (Balaenoptera physalus), blue
(Balaenoptera musculus), and/or sperm whales (Physeter macrocephalus)
will be avoided if possible (i.e., exposing concentrations of animals
to 160 dB), and the array will be powered-down if necessary. For
purposes of the survey, a concentration or group of whales will consist
of six or more individuals visually sighted that do not appear to be
traveling (e.g., feeding, socializing, etc.).
7. Reporting Requirements
The USGS is required to:
(a) Submit a draft comprehensive report on all activities and
monitoring results to the Office of Protected Resources, NMFS, within
90 days of the completion of the Langseth's cruise in the northwest
Atlantic Ocean off the Eastern Seaboard after the end of phase 1 in
2014 and another draft comprehensive report after the end of phase 2 in
2015. This report must contain and summarize the following information:
(i) Dates, times, locations, heading, speed, weather, sea
conditions (including Beaufort sea state and wind force), and
associated activities during all seismic operations and marine mammal
sightings.
(ii) Species, number, location, distance from the vessel, and
behavior of any marine mammals, as well as associated seismic activity
(number of power-downs and shut-downs), observed throughout all
monitoring activities.
(iii) An estimate of the number (by species) of marine mammals
that: (A) Are known to have been exposed to the seismic activity (based
on visual observation) at received levels greater than or equal to 160
dB re 1 [mu]Pa (rms) and/or 180 dB re 1 [mu]Pa (rms) for cetaceans 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 36 airgun array) to the
seismic activity at received levels greater than or equal to 160 dB re
1 [mu]Pa (rms) and/or 180 dB re 1 [mu]Pa (rms) for cetaceans 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); and (B) mitigation measures of the Incidental
Harassment Authorization. For the Biological Opinion, the report shall
confirm the implementation of each Term and Condition, as well as any
conservation recommendations, and describe their effectiveness, for
minimizing the adverse effects of the action on Endangered Species Act-
listed marine mammals.
(b) Submit a final report to the Chief, Permits and Conservation
Division, Office of Protected Resources, NMFS, within 30 days after
receiving comments from NMFS on the draft report. If NMFS decides that
the draft report needs no comments, the draft report shall be
considered to be the final report.
Reporting Prohibited Take
8. In the unanticipated event that the specified activity clearly
causes the take of a marine mammal in a manner prohibited by this
Authorization (if issued), such as an injury (Level A harassment),
serious injury, or mortality (e.g., ship-strike, gear interaction, and/
or entanglement), USGS 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 noaa.gov">Jolie.Harrison@noaa.gov and
[[Page 35676]]
noaa.gov">Howard.Goldstein@noaa.gov and the NMFS Greater Atlantic Region Marine
Mammal Stranding Network at 866-755-6622 (noaa.gov">Mendy.Garron@noaa.gov), and
NMFS Southeast Region Marine Mammal Stranding Network at 877-433-8299
(noaa.gov">Blair.Mase@noaa.gov and noaa.gov">Erin.Fougeres@noaa.gov). The report must
include the following information:
(a) Time, date, and location (latitude/longitude) of the incident;
the name and type of vessel involved; the vessel's speed during and
leading up to the incident; description of the incident; status of all
sound source use in the 24 hours preceding the incident; water depth;
environmental conditions (e.g., wind speed and direction, Beaufort sea
state, cloud cover, and visibility); description of marine mammal
observations in the 24 hours preceding the incident; species
identification or description of the animal(s) involved; the fate of
the animal(s); and photographs or video footage of the animal (if
equipment is available).
USGS shall not resume its activities until NMFS is able to review
the circumstances of the prohibited take. NMFS shall work with USGS to
determine what is necessary to minimize the likelihood of further
prohibited take and ensure MMPA compliance. USGS 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
In the event that USGS discovers an injured or dead marine mammal,
and the lead PSO determines that the cause of the injury or death is
unknown and the death is relatively recent (i.e., in less than a
moderate state of decomposition as described in the next paragraph),
USGS will immediately report the incident to the Chief of the Permits
and Conservation Division, Office of Protected Resources, NMFS, at 301-
427-8401, and/or by email to noaa.gov">Jolie.Harrison@noaa.gov and
noaa.gov">Howard.Goldstein@noaa.gov, and the NMFS Greater Atlantic Region Marine
Mammal Stranding Network (866-755-6622) and/or by email to the NMFS
Greater Atlantic Regional Stranding Coordinator
(noaa.gov">Mendy.Garron@noaa.gov), and the NMFS Southeast Region Marine Mammal
Stranding Network (877-433-8299) and/or by email to the Southeast
Regional Stranding Coordinator (noaa.gov">Blair.Mase@noaa.gov) and Southeast
Regional Stranding Program Administrator (noaa.gov">Erin.Fougeres@noaa.gov). The
report must include the same information identified in Condition 8(a)
above. Activities may continue while NMFS reviews the circumstances of
the incident. NMFS will work with USGS 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 USGS 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), USGS 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
noaa.gov">Jolie.Harrison@noaa.gov and noaa.gov">Howard.Goldstein@noaa.gov, and the NMFS
Greater Atlantic Marine Mammal Stranding Network (866-755-622), and/or
by email to the Greater Atlantic Regional Stranding Coordinator
(noaa.gov">Mendy.Garron@noaa.gov), and the NMFS Southeast Regional Stranding
Network (877-433-8299), and/or by email to the Southeast Stranding
Coordinator (noaa.gov">Blair.Mase@noaa.gov) and Southeast Regional Stranding
Program Administrator (noaa.gov">Erin.Fourgeres@noaa.gov), within 24 hours of the
discovery. USGS shall provide photographs or video footage (if
available) or other documentation of the stranded animal sighting to
NMFS and the Marine Mammal Stranding Network. Activities may continue
while NMFS reviews the circumstances of the incident.
Endangered Species Act (ESA) Biological Opinion and Incidental Take
Statement (ITS)
9. USGS is required to comply with the Terms and Conditions of the
ITS corresponding to NMFS's ESA Biological Opinion issued to both USGS
and NMFS's Office of Protected Resources, Permits and Conservation
Division.
10. A copy of this Authorization and the ITS must be in the
possession of all contractors and PSOs operating under the authority of
this Incidental Harassment Authorization.
Request for Public Comments
NMFS requests comments on our analysis, the draft authorization,
and any other aspect of the notice of proposed IHA for USGS's proposed
marine seismic survey in the Atlantic Ocean off the Eastern Seaboard.
Please include with your comments any supporting data or literature
citations to help inform our final decision on USGS'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: June 16, 2014.
Perry F. Gayaldo,
Deputy Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2014-14426 Filed 6-20-14; 8:45 am]
BILLING CODE 3510-22-P