[Federal Register Volume 83, Number 87 (Friday, May 4, 2018)]
[Notices]
[Pages 19711-19736]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-09481]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XF984
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Marine Site Characterization
Surveys Off of Rhode Island and Massachusetts
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 a request from Deepwater Wind New England,
LLC (DWW), for authorization to take marine mammals incidental to
marine site characterization surveys off the coast of Rhode Island and
Massachusetts in the area of the Commercial Lease of Submerged Lands
for Renewable Energy Development on the Outer Continental Shelf (OCS-A
0486) and along potential submarine cable routes to a landfall location
in Rhode Island, Massachusetts or New York. Pursuant to the Marine
Mammal Protection Act (MMPA), NMFS is requesting comments on its
proposal to issue an incidental harassment authorization (IHA) to
incidentally take marine mammals during the specified activities. NMFS
will consider public comments prior to making any final decision on the
issuance of the requested MMPA authorizations and agency responses will
be summarized in the final notice of our decision.
DATES: Comments and information must be received no later than June 4,
2018.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service. Physical comments should be sent to
1315 East-West Highway, Silver Spring, MD 20910 and electronic comments
should be sent to [email protected].
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments received electronically, including
all attachments, must not exceed a 25-megabyte file size. Attachments
to electronic comments will be accepted in Microsoft Word or Excel or
Adobe PDF file formats only. All comments received are a part of the
public record and will generally be posted online at
www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable without change.
All personal identifying information (e.g., name, address) voluntarily
submitted by the commenter may be publicly accessible. Do not submit
confidential business information or otherwise sensitive or protected
information.
FOR FURTHER INFORMATION CONTACT: Jordan Carduner, Office of Protected
Resources, NMFS, (301) 427-8401. Electronic copies of the applications
and supporting documents, as well as a list of the references cited in
this document, may be obtained by visiting the internet at:
www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable. In case of
problems accessing these documents, please call the contact listed
above.
SUPPLEMENTARY INFORMATION:
Background
Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.)
direct the Secretary of Commerce (as delegated to NMFS) to allow, upon
request, the incidental, but not intentional, taking of small numbers
of marine mammals by U.S. citizens who engage in a specified activity
(other than commercial fishing) within a specified geographical region
if certain findings are made and either regulations are issued or, if
the taking is limited to harassment, a notice of a proposed
authorization is provided to the public for review.
An authorization for incidental takings shall be granted if NMFS
finds that the taking will have a negligible impact on the species or
stock(s), will not have an unmitigable adverse impact on the
availability of the species or stock(s) for subsistence uses (where
relevant), and if the permissible methods of taking and requirements
pertaining to the mitigation, monitoring and reporting of such takings
are set forth.
NMFS has defined ``negligible impact'' in 50 CFR 216.103 as an
impact resulting from the specified activity that cannot be reasonably
expected to, and is not reasonably likely to, adversely affect the
species or stock through effects on annual rates of recruitment or
survival.
[[Page 19712]]
The MMPA states that the term ``take'' means to harass, hunt,
capture, or kill, or attempt to harass, hunt, capture, or kill any
marine mammal.
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).
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an
incidental harassment authorization) with respect to potential impacts
on the human environment.
Accordingly, NMFS is preparing an Environmental Assessment (EA) to
consider the environmental impacts associated with the issuance of the
proposed IHA. We will review all comments submitted in response to this
notice prior to concluding our NEPA process or making a final decision
on the IHA request.
Summary of Request
On January 3, 2018, NMFS received a request from DWW for an IHA to
take marine mammals incidental to marine site characterization surveys
off the coast of Massachusetts and Rhode Island in the area of the
Commercial Lease of Submerged Lands for Renewable Energy Development on
the Outer Continental Shelf (OCS-A 0486) and along potential submarine
cable routes to a landfall location in either Rhode Island,
Massachusetts or New York. A revised application was received on April
18, 2018. NMFS deemed that request to be adequate and complete. DWW's
request is for take of 14 marine mammal species by Level B harassment.
Neither DWW nor NMFS expects serious injury or mortality to result from
this activity and the activity is expected to last no more than one
year, therefore, an IHA is appropriate.
Description of the Proposed Activity
Overview
DWW proposes to conduct marine site characterization surveys,
including high-resolution geophysical (HRG) and geotechnical surveys,
in the area of Commercial Lease of Submerged Lands for Renewable Energy
Development on the Outer Continental Shelf #OCS-A 0486 (Lease Area) and
along potential submarine cable routes to landfall locations in either
Rhode Island, Massachusetts or Long Island, New York. Surveys would
occur from approximately June 15, 2018 through December 31, 2018.
The purpose of the marine site characterization surveys are to
obtain a baseline assessment of seabed/sub-surface soil conditions in
the Lease Area and cable route corridors to support the siting of
potential future offshore wind projects. Underwater sound resulting
from DWW's proposed site characterization surveys has the potential to
result in incidental take of marine mammals in the form of behavioral
harassment.
Dates and Duration
The estimated duration of the geophysical survey is expected to be
up to 200 days between June 15, 2018, and December 31, 2018. The
geotechnical surveys are expected to take up to 100 days between June
15, 2018, and December 31, 2018. This schedule is based on 24-hour
operations and includes potential down time due to inclement weather.
Surveys will last for approximately seven months and are anticipated to
commence upon issuance of the requested IHA, if appropriate.
Specific Geographic Region
DWW's survey activities would occur in the Northwest Atlantic Ocean
within Federal waters. Surveys would occur in the Lease Area and along
potential submarine cable routes to landfall locations in either Rhode
Island, Massachusetts or Long Island, New York (see Figure 1 in the IHA
application). The Lease Area is approximately 394 square kilometers
(km\2\) (97,498 acres) and is approximately 20 km south of Rhode Island
at its closest point to land.
Detailed Description of the Specified Activities
DWW's proposed marine site characterization surveys include HRG and
geotechnical survey activities. Surveys would occur within the Bureau
of Ocean Energy Management (BOEM) Rhode Island-Massachusetts Wind
Energy Area (RI-MA WEA) which is east of Long Island, New York and
south of Rhode Island and Massachusetts (see Figure 1 in the IHA
application). Water depths in the Lease Area range from 26 to 48 meters
(m) (85 to 157 feet (ft)). For the purpose of this IHA the Lease Area
and submarine cable corridor are collectively termed the Project Area.
Geophysical and shallow geotechnical survey activities are
anticipated to be supported by a vessel approximately 20-70 m long
which will maintain a speed of up to five knots (kn) while transiting
survey lines. Near shore geophysical and shallow geotechnical surveys
(if required) would be performed by shallow draft vessels approximately
9 to 23 m long which will maintain a speed of up to five kn while
transiting survey lines. Deep geotechnical survey activities and
possible shallow geotechnical activities are anticipated to be
conducted from a 40 to 100 m dynamically positioned (DP) vessel, jack-
up vessel, or anchored vessel, with support of a tug boat. Survey
activities will be executed in compliance with the July 2015 BOEM
Guidelines for Providing Geophysical, Geotechnical, and Geohazard
Information Pursuant to 30 CFR part 585. The proposed HRG and
geotechnical survey activities are described below.
Geotechnical Survey Activities
DWW's proposed geotechnical survey activities would include the
following:
Vibracores to characterize the geological and geotechnical
characteristics of the seabed, up to approximately 5 m deep. A
hydraulic or electric driven pulsating head is used to drive a hollow
tube into the seafloor and recover a stratified representation of the
sediment.
Core Penetration Testing (CPT) to determine stratigraphy
and in-situ conditions of the sediments. Target penetration is 60 to 75
m.
Deep Boring Cores would be drilled to determine the
vertical and lateral variation in seabed conditions and provide
geotechnical data to depths at least 10 m deeper than design
penetration of the foundations (60 to 75 m target penetration).
Shallow geotechnical surveys, consisting of CPTs and vibracores,
are planned for within the Lease Area and approximately every one to
two kilometers (km) along the export cable routes. Foundation-depth
geotechnical borings are also planned at each proposed foundation
location within the Lease Area. While the quantity and locations of
wind turbine generators to be installed, as well as cable route, has
yet to be determined, an estimate of 153 vibracores, 20 CPTs, and 16
deep borings are planned within the Lease Area and along the export
cable routes.
In considering whether marine mammal harassment is an expected
outcome of exposure to a particular
[[Page 19713]]
activity or sound source, NMFS considers the nature of the exposure
itself (e.g., the magnitude, frequency, or duration of exposure),
characteristics of the marine mammals potentially exposed, and the
conditions specific to the geographic area where the activity is
expected to occur (e.g., whether the activity is planned in a foraging
area, breeding area, nursery or pupping area, or other biologically
important area for the species). We then consider the expected response
of the exposed animal and whether the nature and duration or intensity
of that response is expected to cause disruption of behavioral patterns
(e.g., migration, breathing, nursing, breeding, feeding, or sheltering)
or injury.
Geotechnical survey activities would be conducted from a drill ship
equipped with DP thrusters. DP thrusters would be used to position the
sampling vessel on station and maintain position at each sampling
location during the sampling activity. Sound produced through use of DP
thrusters is similar to that produced by transiting vessels and DP
thrusters are typically operated either in a similarly predictable
manner or used for short durations around stationary activities. NMFS
does not believe acoustic impacts from DP thrusters are likely to
result in take of marine mammals in the absence of activity- or
location-specific circumstances that may otherwise represent specific
concerns for marine mammals (i.e., activities proposed in area known to
be of particular importance for a particular species), or associated
activities that may increase the potential to result in take when in
concert with DP thrusters. In this case, we are not aware of any such
circumstances. Monitoring of past projects that entailed use of DP
thrusters has shown a lack of observed marine mammal responses as a
result of exposure to sound from DP thrusters. Therefore, NMFS believes
the likelihood of DP thrusters used during the proposed geotechnical
surveys resulting in harassment of marine mammals to be so low as to be
discountable. As DP thrusters are not expected to result in take of
marine mammals, these activities are not analyzed further in this
document.
Vibracoring entails driving a hydraulic or electric pulsating head
through a hollow tube into the seafloor to recover a stratified
representation of the sediment. The vibracoring process is short in
duration and is performed from a dynamic positioning vessel. The vessel
would use DP thrusters to maintain the vessel's position while the
vibracore sample is taken, as described above. The vibracoring process
would always be performed in concert with DP thrusters, and DP
thrusters would begin operating prior to the activation of the
vibracore to maintain the vessel's position; thus, we expect that any
marine mammals in the project area would detect the presence and noise
associated with the vessel and the DP thrusters prior to commencement
of vibracoring. Any reaction by marine mammals would be expected to be
similar to reactions to the concurrent DP thrusters, which are expected
to be minor and short term, i.e., not constituting Level B harassment,
as defined by the MMPA. In this case, vibracoring is not planned in any
areas of particular biological significance for any marine mammals.
Thus while a marine mammal may perceive noise from vibracoring and may
respond briefly, we believe the potential for this response to rise to
the level of take to be so low as to be discountable, based on the
short duration of the activity and the fact that marine mammals would
be expected to react to the vessel and DP thrusters before vibracoring
commences, potentially through brief avoidance. In addition, the fact
that the geographic area is not biologically important for any marine
mammal species means that such reactions are not likely to carry any
meaningful significance for the animals.
Field studies conducted off the coast of Virginia to determine the
underwater noise produced by CPTs and borehole drilling found that
these activities did not result in underwater noise levels that
exceeded current thresholds for Level B harassment of marine mammals
(Kalapinski, 2015). Given the small size and energy footprint of CPTs
and boring cores, NMFS believes the likelihood that noise from these
activities would exceed the Level B harassment threshold at any
appreciable distance is so low as to be discountable. Therefore,
geotechnical survey activities, including CPTs, boring cores and
vibracores, are not expected to result in harassment of marine mammals
and are not analyzed further in this document.
Geophysical Survey Activities
DWW has proposed that HRG survey operations would be conducted
continuously 24 hours per day. Based on 24-hour operations, the
estimated duration of the geophysical survey activities would be
approximately 200 days (including estimated weather down time). The
geophysical survey activities proposed by DWW would include the
following:
Multibeam Depth Sounder to determine water depths and
general bottom topography. The multibeam echosounder sonar system
projects sonar pulses in several angled beams from a transducer mounted
to a ship's hull. The beams radiate out from the transducer in a fan-
shaped pattern orthogonally to the ship's direction.
Shallow Penetration Sub-Bottom Profiler (Chirp) to map the
near surface stratigraphy (top 0 to 5 m of sediment below seabed). A
Chirp system emits sonar pulses which increase in frequency (3.5 to 200
kHz) over time. The pulse length frequency range can be adjusted to
meet project variables.
Medium Penetration Sub-Bottom Profiler (Boomer) to map
deeper subsurface stratigraphy as needed. This system is commonly
mounted on a sled and towed behind a boat.
Medium Penetration Sub-Bottom Profiler (Sparker and/or
bubble gun) to map deeper subsurface stratigraphy as needed. Sparkers
create acoustic pulses omni-directionally from the source that can
penetrate several hundred meters into the seafloor. Hydrophone arrays
towed nearby receive the return signals.
Sidescan Sonar used to image the seafloor for seabed
sediment classification purposes and to identify natural and man-made
acoustic targets on the seafloor. The sonar device emits conical or
fan-shaped pulses down toward the seafloor in multiple beams at a wide
angle, perpendicular to the path of the sensor through the water. The
acoustic return of the pulses is recorded in a series of cross-track
slices, which can be joined to form an image of the sea bottom within
the swath of the beam.
Marine Magnetometer to detect ferrous metal objects on the
seafloor which may cause a hazard including anchors, chains, cables,
pipelines, ballast stones and other scattered shipwreck debris,
munitions of all sizes, unexploded ordinances, aircraft, engines and
any other object with magnetic expression.
Table 1 identifies the representative survey equipment that may be
used in support of planned geophysical survey activities. The make and
model of the listed geophysical equipment will vary depending on
availability and the final equipment choices will vary depending upon
the final survey design, vessel availability, and survey contractor
selection. Geophysical surveys are expected to use several equipment
types concurrently in order to collect multiple aspects of geophysical
data along one transect. Selection of equipment combinations is based
on specific survey objectives. Any survey equipment selected would have
characteristics similar to the systems described below, if different.
[[Page 19714]]
Table 1--Summary of Geophysical Survey Equipment Proposed for Use by DWW
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Source level (SLrms dB re 1 Operational depth (meters Pulse duration
Equipment type Operating frequencies (kHz) [mu]PA @1 m) below surface) Beam width (degrees) (milliseconds)
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Multibeam Depth Sounding
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Reson SeaBat 7125 \1\.............. 200 and 400................... 220........................... 4............................ 128.......................... 0.03 to 0.3.
Reson SeaBat 7101 \2\.............. 100........................... 162........................... 2 to 5....................... 140.......................... 0.8 to 3.04.
R2SONIC Sonic 2020 \1\............. 170 to 450.................... 162........................... 2 to 5....................... 160.......................... 0.11.
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Shallow Sub-bottom Profiling
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Teledyne Benthos Chirp III \3\..... 2 to 7........................ 197........................... 4............................ 45........................... 0.2.
EdgeTech SB3200 XS................. 2 to 16....................... 176........................... 2 to 5....................... 170.......................... 3.4.
SB216 \4\..........................
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Medium Penetration Sub-bottom Profiling
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Applied Acoustics.................. 0.1 to 10..................... 175........................... 1 to 2....................... 60........................... 58.
Fugro boomer \1\...................
Applied Acoustics.................. 0.25 to 8..................... 203........................... 2............................ 25 to 35..................... 0.6.
S-Boom system--CSP-D 2400HV........
(600 joule/pulse) \5\..............
GeoResources 800 Joule Sparker \6\. 0.75 to 2.75.................. 203........................... 4............................ 360 (omni-directional)....... 0.1 to 0.2.
Falmouth Scientific HMS 620 bubble 0.02 to 1.7................... 196........................... 1.5.......................... 360 (omni-directional)....... 1.6.
gun \7\.
Applied Acoustics.................. 0.03 to 5..................... 213........................... 1 to 2....................... 170.......................... 2.1.
Dura-Spark 240 \5\.................
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Side Scan Sonar
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Klein Marine Systems model 3900 \1\ 445 and 900................... 242........................... 20........................... 40........................... 0.025.
EdgeTech model 4125 \1\............ 105 and 410................... 225........................... 10........................... 158.......................... 10 to 20.
EdgeTech model 4200 \1\............ 300 and 600................... 215 to 220.................... 1............................ 0.5 and 0.26................. 5 to 12.
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\1\ Source level obtained from equipment specifications as described in 2017 IHA issued to DWW for takes of marine mammals incidental to site characterization surveys off the coast of New York
(82 FR 22250).
\2\ Source level based on published manufacturer specifications and/or systems manual.
\3\ Source level based on published manufacturer specifications and/or systems manual--assumed configured as TTV-171 with AT-471 transducer per system manual.
\4\ Source level obtained from Crocker and Fratantonio (2016). Assumed to be 3200 XS with SB216. Used as proxy: 3200 XS with SB424 in 4-24 kHz mode Since the 3200 XS system manual lists same
power output between SB216 and SB 424.
\5\ Source level obtained from Crocker and Fratantonio (2016).
\6\ Source level obtained from Crocker and Fratantonio (2016)--ELC820 used as proxy.
\7\ Source level obtained from Crocker and Fratantonio (2016)--Used single plate 1 due to discrepancies noted in Crocker and Fratantonio (2016) regarding plate 2.
The deployment of HRG survey equipment, including the equipment
planned for use during DWW's planned activity, produces sound in the
marine environment that has the potential to result in harassment of
marine mammals. However, sound propagation is dependent on several
factors including operating mode, frequency and beam direction of the
HRG equipment; thus, potential impacts to marine mammals from HRG
equipment are driven by the specification of individual HRG sources.
The specifications of the potential equipment planned for use during
HRG survey activities (Table 1) were analyzed to determine which types
of equipment would have the potential to result in harassment of marine
mammals. HRG equipment that would be operated either at frequency
ranges that fall outside the functional hearing ranges of marine
mammals (e.g., above 200 kHz) or that operate within marine mammal
functional hearing ranges but have low sound source levels (e.g., a
single pulse at less than 200 dB re re 1 [mu]Pa) were assumed to not
have the potential to result in marine mammal harassment and were
therefore eliminated from further analysis. Of the potential HRG survey
equipment planned for use, the following equipment was determined to
have the potential to result in harassment of marine mammals:
Teledyne Benthos Chirp III Sub-bottom Profiler;
EdgeTech Sub-bottom Profilers (Chirp);
Applied Acoustics Fugro Sub-bottom Profiler (Boomer);
Applied Acoustics S-Boom Sub-bottom Profiling System
consisting of a CSP-D 2400HV power supply and 3-plate catamaran;
GeoResources 800 Joule Sparker;
Falmouth Scientific HMS 620 Bubble Gun; and
Applied Acoustics Dura-Spark 240 System.
As the HRG survey equipment listed above was determined to have the
potential to result in harassment of marine mammals, the equipment
listed above was carried forward in the analysis of potential impacts
to marine mammals; all other HRG equipment planned for use by DWW is
not expected to result in harassment of marine mammals and is therefore
not analyzed further in this document.
Proposed mitigation, monitoring, and reporting measures are
described in
[[Page 19715]]
detail later in this document (please see ``Proposed Mitigation'' and
``Proposed Monitoring and Reporting'').
Description of Marine Mammals in the Area of Specified Activity
Sections 3 and 4 of DWW's IHA application summarize available
information regarding status and trends, distribution and habitat
preferences, and behavior and life history, of the potentially affected
species. Additional information regarding population trends and threats
may be found in NMFS' Stock Assessment Reports (SAR; www.nmfs.noaa.gov/pr/sars/) and more general information about these species (e.g.,
physical and behavioral descriptions) may be found on NMFS' website
(www.nmfs.noaa.gov/pr/species/mammals/). All species that could
potentially occur in the proposed survey areas are included in Table 5
of the IHA application. However, the temporal and/or spatial occurrence
of several species listed in Table 5 of the IHA application is such
that take of these species is not expected to occur, and they are not
discussed further beyond the explanation provided here. Take of these
species is not anticipated either because they have very low densities
in the project area, are known to occur further offshore than the
project area, or are considered very unlikely to occur in the project
area during the proposed survey due to the species' seasonal occurrence
in the area.
Table 2 lists all species with expected potential for occurrence in
the survey area and with the potential to be taken as a result of the
proposed survey and summarizes information related to the population or
stock, including regulatory status under the MMPA and ESA and potential
biological removal (PBR), where known. For taxonomy, we follow
Committee on Taxonomy (2017). PBR is defined by the MMPA as the maximum
number of animals, not including natural mortalities, that may be
removed from a marine mammal stock while allowing that stock to reach
or maintain its optimum sustainable population (as described in NMFS'
SARs). While no mortality is anticipated or authorized here, PBR is
included here as a gross indicator of the status of the species and
other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' U.S. Atlantic SARs (e.g., Hayes et al., 2018). All values
presented in Table 2 are the most recent available at the time of
publication and are available in the 2017 draft Atlantic SARs (Hayes et
al., 2018).
Table 2--Marine Mammals Known To Occur in the Survey Area
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NMFS MMPA and Stock abundance
ESA status; (CV,Nmin, most recent Predicted PBR Occurrence and
Common name Stock strategic (Y/N) abundance survey) \2\ abundance \4\ seasonality in the
\1\ (CV) \3\ survey area
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Toothed whales (Odontoceti)
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Sperm whale (Physeter macrocephalus) North Atlantic......... E; Y 2,288 (0.28; 1,815; n/ 5,353 (0.12) 3.6 Rare.
a).
Long-finned pilot whale W North Atlantic....... -; Y 5,636 (0.63; 3,464; n/ \5\ 18,977 35 Rare.
(Globicephala melas). a). (0.11)
Atlantic white-sided dolphin W North Atlantic....... -; N 48,819 (0.61; 30,403; 37,180 (0.07) 304 Rare.
(Lagenorhynchus acutus). n/a).
Atlantic spotted dolphin (Stenella W North Atlantic....... -; N 44,715 (0.43; 31,610; 55,436 (0.32) 316 Rare.
frontalis). n/a).
Bottlenose dolphin (Tursiops W North Atlantic, -; N 77,532 (0.40; 56,053; \5\ 97,476 561 Common year round.
truncatus). Offshore. 2011). (0.06)
Common dolphin \6\ (Delphinus W North Atlantic....... -; N 173,486 (0.55; 55,690; 86,098 (0.12) 557 Common year round.
delphis). 2011).
Harbor porpoise (Phocoena phocoena). Gulf of Maine/Bay of -; N 79,833 (0.32; 61,415; * 45,089 706 Common year round.
Fundy. 2011). (0.12)
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Baleen whales (Mysticeti)
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North Atlantic right whale W North Atlantic....... E; Y 458 (0; 455; n/a)..... * 535 (0.45) 1.4 Year round in
(Eubalaena glacialis). continental shelf and
slope waters, occur
seasonally to forage.
Humpback whale \7\ (Megaptera Gulf of Maine.......... -; N 823 (0.42; 239; n/a).. * 1,637 (0.07) 3.7 Common year round.
novaeangliae).
Fin whale \6\ (Balaenoptera W North Atlantic....... E; Y 3,522 (0.27; 1,234; n/ 4,633 (0.08) 2.5 Year round in
physalus). a). continental shelf and
slope waters, occur
seasonally to forage.
Sei whale (Balaenoptera borealis)... Nova Scotia............ E; Y 357 (0.52; 236; n/a).. * 717 (0.30) 0.5 Year round in
continental shelf and
slope waters, occur
seasonally to forage.
Minke whale \6\ (Balaenoptera Canadian East Coast.... -; N 20,741 (0.3; 1,425; n/ * 2,112 (0.05) 162 Year round in
acutorostrata). a). continental shelf and
slope waters, occur
seasonally to forage.
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Earless seals (Phocidae)
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Gray seal \8\ (Halichoerus grypus).. W North Atlantic....... -; N 27,131 (0.10; 25,908; .............. 1,554 Rare.
n/a).
Harbor seal (Phoca vitulina)........ W North Atlantic....... -; N 75,834 (0.15; 66,884; .............. 2,006 Common year round.
2012).
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\1\ ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or
designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR (see
footnote 3) or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
[[Page 19716]]
\2\ Stock abundance as reported in NMFS marine mammal stock assessment reports except where otherwise noted. NMFSs abundance reports available online
at: www.nmfs.noaa.gov/pr/sars. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable.
For certain stocks, abundance estimates are actual counts of animals and there is no associated CV. The most recent abundance survey that is reflected
in the abundance estimate is presented; there may be more recent surveys that have not yet been incorporated into the estimate. All values presented
here are from the 2017 draft Atlantic SARs.
\3\ This information represents species- or guild-specific abundance predicted by recent habitat-based cetacean density models (Roberts et al., 2016).
These models provide the best available scientific information regarding predicted density patterns of cetaceans in the U.S. Atlantic Ocean, and we
provide the corresponding abundance predictions as a point of reference. Total abundance estimates were produced by computing the mean density of all
pixels in the modeled area and multiplying by its area. For those species marked with an asterisk, the available information supported development of
either two or four seasonal models; each model has an associated abundance prediction. Here, we report the maximum predicted abundance.
\4\ Potential biological removal, defined by the MMPA as the maximum number of animals, not including natural mortalities, that may be removed from a
marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population size (OSP).
\5\ Abundance estimates are in some cases reported for a guild or group of species when those species are difficult to differentiate at sea. Similarly,
the habitat-based cetacean density models produced by Roberts et al. (2016) are based in part on available observational data which, in some cases, is
limited to genus or guild in terms of taxonomic definition. Roberts et al. (2016) produced density models to genus level for Globicephala spp. and
produced a density model for bottlenose dolphins that does not differentiate between offshore and coastal stocks.
\6\ Abundance as reported in the 2007 Canadian Trans-North Atlantic Sighting Survey (TNASS), which provided full coverage of the Atlantic Canadian coast
(Lawson and Gosselin, 2009). Abundance estimates from TNASS were corrected for perception and availability bias, when possible. In general, where the
TNASS survey effort provided superior coverage of a stock's range (as compared with NOAA shipboard survey effort), the resulting abundance estimate is
considered more accurate than the current NMFS abundance estimate (derived from survey effort with inferior coverage of the stock range). NMFS stock
abundance estimate for the common dolphin is 70,184. NMFS stock abundance estimate for the fin whale is 1,618.
\7\ 2017 U.S. Atlantic draft SAR for the Gulf of Maine feeding population lists a current abundance estimate of 335 individuals; this estimate was
revised from the previous estimate of 823 individuals. However, the newer estimate is based on a single aerial line-transect survey in the Gulf of
Maine. The 2017 U.S. Atlantic draft SAR notes that that previous estimate was based on a minimum number alive calculation which is generally more
accurate than one derived from line-transect survey (Hayes et al., 2017), and that the abundance estimate was revised solely because the previous
estimate was greater than 8 years old. Therefore, the previous estimate of 823 is more accurate, and we note that even that estimate is defined on the
basis of feeding location alone (i.e., Gulf of Maine).
\8\ NMFS stock abundance estimate applies to U.S. population only, actual stock abundance is approximately 505,000.
Four marine mammal species that are listed under the Endangered
Species Act (ESA) may be present in the survey area and are included in
the take request: The North Atlantic right whale, fin whale, sei whale,
and sperm whale.
Below is a description of the species that are both common in the
survey area south of Rhode Island and Massachusetts that have the
highest likelihood of occurring, at least seasonally, in the survey
area and are thus are expected to potentially be taken by the proposed
activities. Though other marine mammal species are known to occur in
the Northwest Atlantic Ocean, the temporal and/or spatial occurrence of
several of these species is such that take of these species is not
expected to occur, and they are therefore not discussed further beyond
the explanation provided here. Take of these species is not anticipated
either because they have very low densities in the project area (e.g.,
blue whale, Clymene dolphin, pantropical spotted dolphin, striped
dolphin, spinner dolphin, killer whale, false killer whale, pygmy
killer whale, short-finned pilot whale), or, are known to occur further
offshore than the project area (e.g., beaked whales, rough toothed
dolphin, Kogia spp.). For the majority of species potentially present
in the specific geographic region, NMFS has designated only a single
generic stock (e.g., ``western North Atlantic'') for management
purposes. This includes the ``Canadian east coast'' stock of minke
whales, which includes all minke whales found in U.S. waters. For
humpback and sei whales, NMFS defines stocks on the basis of feeding
locations, i.e., Gulf of Maine and Nova Scotia, respectively. However,
our reference to humpback whales and sei whales in this document refers
to any individuals of the species that are found in the specific
geographic region.
North Atlantic Right Whale
The North Atlantic right whale ranges from the calving grounds in
the southeastern United States to feeding grounds in New England waters
and into Canadian waters (Waring et al., 2016). Surveys have
demonstrated the existence of seven areas where North Atlantic right
whales congregate seasonally, including north and east of the proposed
survey area in Georges Bank, off Cape Cod, and in Massachusetts Bay
(Waring et al., 2016). In the late fall months (e.g. October), right
whales are generally thought to depart from the feeding grounds in the
North Atlantic and move south to their calving grounds off Florida.
However, recent research indicates our understanding of their movement
patterns remains incomplete (Davis et al. 2017). A review of passive
acoustic monitoring data from 2004 to 2014 throughout the western North
Atlantic Ocean demonstrated nearly continuous year-round right whale
presence across their entire habitat range, including in locations
previously thought of as migratory corridors, suggesting that not all
of the population undergoes a consistent annual migration (Davis et al.
2017). Acoustic monitoring data from 2004 to 2014 indicated that the
number of North Atlantic right whale vocalizations detected in the
proposed survey area were relatively constant throughout the year, with
the exception of August through October when detected vocalizations
showed an apparent decline (Davis et al. 2017). North Atlantic right
whales are expected to be present in the proposed survey area during
the proposed survey, especially during the summer months, with numbers
possibly lower in the fall.
The western North Atlantic population demonstrated overall growth
of 2.8 percent per year between 1990 to 2010, despite a decline in 1993
and no growth between 1997 and 2000 (Pace et al. 2017). However, since
2010 the population has been in decline, with a 99.99 percent
probability of a decline of just under 1 percent per year (Pace et al.
2017). Between 1990 and 2015, calving rates varied substantially, with
low calving rates coinciding with all three periods of decline or no
growth (Pace et al. 2017). On average, North Atlantic right whale
calving rates are estimated to be roughly half that of southern right
whales (Eubalaena australis) (Pace et al. 2017), which are increasing
in abundance (NMFS 2015). In 2018, no new North Atlantic right whale
calves were documented in their calving grounds; this represented the
first time since annual NOAA aerial surveys began in 1989 that no new
right whale calves were observed.
Data indicates that the number of adult females fell from 200 in
2010 to 186 in 2015 while males fell from 283 to 272 in the same time
frame (Pace et al., 2017). In addition, elevated North Atlantic right
whale mortalities have occurred since June 7, 2017. A total of 18
confirmed dead stranded whales (12 in Canada; 6 in the United States),
with an additional 5 live whale entanglements in Canada, have been
documented to date. This event has been declared an Unusual Mortality
Event (UME), with human interactions (i.e., fishery-related
entanglements and vessel strikes) identified as the most likely cause.
More information is available online at: http://www.nmfs.noaa.gov/pr/health/mmume/2017northatlanticrightwhaleume.html.
The proposed survey area is part of an important migratory area for
North Atlantic right whales; this important
[[Page 19717]]
migratory area is comprised of the waters of the continental shelf
offshore the East Coast of the United States and extends from Florida
through Massachusetts. NMFS' regulations at 50 CFR part 224.105
designated nearshore waters of the Mid-Atlantic Bight as Mid-Atlantic
U.S. Seasonal Management Areas (SMA) for right whales in 2008. SMAs
were developed to reduce the threat of collisions between ships and
right whales around their migratory route and calving grounds. A
portion of one SMA, which occurs off Block Island, Rhode Island,
overlaps spatially with a section of the proposed survey area. The SMA
which occurs off Block Island is active from November 1 through April
30 of each year.
Humpback Whale
Humpback whales are found worldwide in all oceans. Humpback whales
were listed as endangered under the Endangered Species Conservation Act
(ESCA) in June 1970. In 1973, the ESA replaced the ESCA, and humpbacks
continued to be listed as endangered. NMFS recently evaluated the
status of the species, and on September 8, 2016, NMFS divided the
species into 14 distinct population segments (DPS), removed the current
species-level listing, and in its place listed four DPSs as endangered
and one DPS as threatened (81 FR 62259; September 8, 2016). The
remaining nine DPSs were not listed. The West Indies DPS, which is not
listed under the ESA, is the only DPS of humpback whale that is
expected to occur in the survey area. The best estimate of population
abundance for the West Indies DPS is 12,312 individuals, as described
in the NMFS Status Review of the Humpback Whale under the Endangered
Species Act (Bettridge et al., 2015).
In New England waters, feeding is the principal activity of
humpback whales, and their distribution in this region has been largely
correlated to abundance of prey species, although behavior and
bathymetry are factors influencing foraging strategy (Payne et al.
1986, 1990). Humpback whales are frequently piscivorous when in New
England waters, feeding on herring (Clupea harengus), sand lance
(Ammodytes spp.), and other small fishes, as well as euphausiids in the
northern Gulf of Maine (Paquet et al. 1997). During winter, the
majority of humpback whales from North Atlantic feeding areas
(including the Gulf of Maine) mate and calve in the West Indies, where
spatial and genetic mixing among feeding groups occurs, though
significant numbers of animals are found in mid- and high-latitude
regions at this time and some individuals have been sighted repeatedly
within the same winter season, indicating that not all humpback whales
migrate south every winter (Waring et al., 2016).
Since January 2016, elevated humpback whale mortalities have
occurred along the Atlantic coast from Maine through North Carolina.
Partial or full necropsy examinations have been conducted on
approximately half of the 62 known cases. A portion of the whales have
shown evidence of pre-mortem vessel strike; however, this finding is
not consistent across all of the whales examined so more research is
needed. NOAA is consulting with researchers that are conducting studies
on the humpback whale populations, and these efforts may provide
information on changes in whale distribution and habitat use that could
provide additional insight into how these vessel interactions occurred.
Three previous UMEs involving humpback whales have occurred since 2000,
in 2003, 2005, and 2006. More information is available at
www.nmfs.noaa.gov/pr/health/mmume/2017humpbackatlanticume.html.
Fin Whale
Fin whales are common in waters of the U. S. Atlantic Exclusive
Economic Zone (EEZ), principally from Cape Hatteras northward (Waring
et al., 2016). Fin whales are present north of 35-degree latitude in
every season and are broadly distributed throughout the western North
Atlantic for most of the year, though densities vary seasonally (Waring
et al., 2016). Fin whales are found in small groups of up to five
individuals (Brueggeman et al., 1987). The main threats to fin whales
are fishery interactions and vessel collisions (Waring et al., 2016).
The proposed survey area would overlap spatially and temporally with a
biologically important feeding area for fin whales. The important fin
whale feeding area occurs from March through October and stretches from
an area south of Montauk Point to south of Martha's Vineyard.
Sei Whale
The Nova Scotia stock of sei whales can be found in deeper waters
of the continental shelf edge waters of the northeastern United States
and northeastward to south of Newfoundland. The southern portion of the
stock's range during spring and summer includes the Gulf of Maine and
Georges Bank. Spring is the period of greatest abundance in U.S.
waters, with sightings concentrated along the eastern margin of Georges
Bank and into the Northeast Channel area, and along the southwestern
edge of Georges Bank in the area of Hydrographer Canyon (Waring et al.,
2015). Sei whales occur in shallower waters to feed. Sei whales are
listed as engendered under the ESA and the Nova Scotia stock is
considered strategic and depleted under the MMPA.
Minke Whale
Minke whales can be found in temperate, tropical, and high-latitude
waters. The Canadian East Coast stock can be found in the area from the
western half of the Davis Strait (45 [deg]W) to the Gulf of Mexico
(Waring et al., 2016). This species generally occupies waters less than
100 m deep on the continental shelf. There appears to be a strong
seasonal component to minke whale distribution in which spring to fall
are times of relatively widespread and common occurrence, and when the
whales are most abundant in New England waters, while during winter the
species appears to be largely absent (Waring et al., 2016).
Sperm Whale
The distribution of the sperm whale in the U.S. EEZ occurs on the
continental shelf edge, over the continental slope, and into mid-ocean
regions (Waring et al., 2014). The basic social unit of the sperm whale
appears to be the mixed school of adult females plus their calves and
some juveniles of both sexes, normally numbering 20-40 animals in all.
There is evidence that some social bonds persist for many years
(Christal et al., 1998). This species forms stable social groups, site
fidelity, and latitudinal range limitations in groups of females and
juveniles (Whitehead, 2002). In summer, the distribution of sperm
whales includes the area east and north of Georges Bank and into the
Northeast Channel region, as well as the continental shelf (inshore of
the 100-m isobath) south of New England. In the fall, sperm whale
occurrence south of New England on the continental shelf is at its
highest level, and there remains a continental shelf edge occurrence in
the mid-Atlantic bight. In winter, sperm whales are concentrated east
and northeast of Cape Hatteras.
Long-Finned Pilot Whale
Long-finned pilot whales are found from North Carolina and north to
Iceland, Greenland and the Barents Sea (Waring et al., 2016). In U.S.
Atlantic waters the species is distributed principally along the
continental shelf edge off the northeastern U.S. coast in winter and
early spring and in late spring, pilot whales move onto Georges Bank
and into the Gulf of Maine and more northern waters and remain in
[[Page 19718]]
these areas through late autumn (Waring et al., 2016). Long-finned
pilot whales are not listed under the ESA. The Western North Atlantic
stock is considered strategic under the MMPA.
Atlantic White-Sided Dolphin
White-sided dolphins are found in temperate and sub-polar waters of
the North Atlantic, primarily in continental shelf waters to the 100-m
depth contour from central West Greenland to North Carolina (Waring et
al., 2016). The Gulf of Maine stock is most common in continental shelf
waters from Hudson Canyon to Georges Bank, and in the Gulf of Maine and
lower Bay of Fundy. Sighting data indicate seasonal shifts in
distribution (Northridge et al., 1997). During January to May, low
numbers of white-sided dolphins are found from Georges Bank to Jeffreys
Ledge (off New Hampshire), with even lower numbers south of Georges
Bank, as documented by a few strandings collected on beaches of
Virginia to South Carolina. From June through September, large numbers
of white-sided dolphins are found from Georges Bank to the lower Bay of
Fundy. From October to December, white-sided dolphins occur at
intermediate densities from southern Georges Bank to southern Gulf of
Maine (Payne and Heinemann 1990). Sightings south of Georges Bank,
particularly around Hudson Canyon, occur year round but at low
densities.
Atlantic Spotted Dolphin
Atlantic spotted dolphins are found in tropical and warm temperate
waters ranging from southern New England, south to Gulf of Mexico and
the Caribbean to Venezuela (Waring et al., 2014). This stock regularly
occurs in continental shelf waters south of Cape Hatteras and in
continental shelf edge and continental slope waters north of this
region (Waring et al., 2014). There are two forms of this species, with
the larger ecotype inhabiting the continental shelf and is usually
found inside or near the 200 m isobaths (Waring et al., 2014). Atlantic
spotted dolphins are not listed under the ESA and the stock is not
considered depleted or strategic under the MMPA.
Common Dolphin
The short-beaked common dolphin is found world-wide in temperate to
subtropical seas. In the North Atlantic, short-beaked common dolphins
are commonly found over the continental shelf between the 100-m and
2,000-m isobaths and over prominent underwater topography and east to
the mid-Atlantic Ridge (Waring et al., 2016). Only the western North
Atlantic stock may be present in the Lease Area.
Bottlenose Dolphin
There are two distinct bottlenose dolphin ecotypes in the western
North Atlantic: the coastal and offshore forms (Waring et al., 2016).
The offshore form is distributed primarily along the outer continental
shelf and continental slope in the Northwest Atlantic Ocean from
Georges Bank to the Florida Keys and is the only type that may be
present in the survey area as the survey area is north of the northern
extent of the range of the Western North Atlantic Northern Migratory
Coastal Stock.
Harbor Porpoise
In the Lease Area, only the Gulf of Maine/Bay of Fundy stock may be
present. This stock is found in U.S. and Canadian Atlantic waters and
is concentrated in the northern Gulf of Maine and southern Bay of Fundy
region, generally in waters less than 150 m deep (Waring et al., 2016).
They are seen from the coastline to deep waters (>1800 m; Westgate et
al. 1998), although the majority of the population is found over the
continental shelf (Waring et al., 2016). The main threat to the species
is interactions with fisheries, with documented take in the U.S.
northeast sink gillnet, mid-Atlantic gillnet, and northeast bottom
trawl fisheries and in the Canadian herring weir fisheries (Waring et
al., 2016).
Harbor Seal
The harbor seal is found in all nearshore waters of the North
Atlantic and North Pacific Oceans and adjoining seas above about
30[deg] N (Burns, 2009). In the western North Atlantic, harbor seals
are distributed from the eastern Canadian Arctic and Greenland south to
southern New England and New York, and occasionally to the Carolinas
(Waring et al., 2016). Haulout and pupping sites are located off
Manomet, MA and the Isles of Shoals, ME, but generally do not occur in
areas in southern New England (Waring et al., 2016).
Gray Seal
There are three major populations of gray seals found in the world;
eastern Canada (western North Atlantic stock), northwestern Europe and
the Baltic Sea. Gray seals in the survey area belong to the western
North Atlantic stock. The range for this stock is thought to be from
New Jersey to Labrador. Current population trends show that gray seal
abundance is likely increasing in the U.S. Atlantic EEZ (Waring et al.,
2016). Although the rate of increase is unknown, surveys conducted
since their arrival in the 1980s indicate a steady increase in
abundance in both Maine and Massachusetts (Waring et al., 2016). It is
believed that recolonization by Canadian gray seals is the source of
the U.S. population (Waring et al., 2016).
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Current data indicate that not all marine
mammal species have equal hearing capabilities (e.g., Richardson et
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect
this, Southall et al. (2007) recommended that marine mammals be divided
into functional hearing groups based on directly measured or estimated
hearing ranges on the basis of available behavioral response data,
audiograms derived using auditory evoked potential techniques,
anatomical modeling, and other data. Note that no direct measurements
of hearing ability have been successfully completed for mysticetes
(i.e., low-frequency cetaceans). Subsequently, NMFS (2016) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65
decibel (dB) threshold from the normalized composite audiograms, with
the exception for lower limits for low-frequency cetaceans where the
lower bound was deemed to be biologically implausible and the lower
bound from Southall et al. (2007) retained. The functional groups and
the associated frequencies are indicated below (note that these
frequency ranges correspond to the range for the composite group, with
the entire range not necessarily reflecting the capabilities of every
species within that group):
Low-frequency cetaceans (mysticetes): Generalized hearing
is estimated to occur between approximately 7 Hertz (Hz) and 35
kilohertz (kHz);
Mid-frequency cetaceans (larger toothed whales, beaked
whales, and most delphinids): Generalized hearing is estimated to occur
between approximately 150 Hz and 160 kHz;
High-frequency cetaceans (porpoises, river dolphins, and
members of the genera Kogia and Cephalorhynchus; including two members
of the genus Lagenorhynchus, on the basis of recent echolocation data
[[Page 19719]]
and genetic data): Generalized hearing is estimated to occur between
approximately 275 Hz and 160 kHz; and
Pinnipeds in water; Phocidae (true seals): Generalized
hearing is estimated to occur between approximately 50 Hz to 86 kH.
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt,
2013).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2016) for a review of available information.
Fourteen marine mammal species (twelve cetacean and two pinniped (both
phocid species) have the reasonable potential to co-occur with the
proposed survey activities (see Table 2). Of the cetacean species that
may be present, five are classified as low-frequency cetaceans (i.e.,
all mysticete species), six are classified as mid-frequency cetaceans
(i.e., all delphinid species and the sperm whale), and one is
classified as a high-frequency cetacean (i.e., harbor porpoise).
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section includes a summary and discussion of the ways that
components of the specified activity may impact marine mammals and
their habitat. The ``Estimated Take'' section later in this document
includes a quantitative analysis of the number of individuals that are
expected to be taken by this activity. The ``Negligible Impact Analysis
and Determination'' section considers the content of this section, the
``Estimated Take'' section, and the ``Proposed Mitigation'' section, to
draw conclusions regarding the likely impacts of these activities on
the reproductive success or survivorship of individuals and how those
impacts on individuals are likely to impact marine mammal species or
stocks.
Background on Sound
Sound is a physical phenomenon consisting of minute vibrations that
travel through a medium, such as air or water, and is generally
characterized by several variables. Frequency describes the sound's
pitch and is measured in Hz or kHz, while sound level describes the
sound's intensity and is measured in dB. Sound level increases or
decreases exponentially with each dB of change. The logarithmic nature
of the scale means that each 10-dB increase is a 10-fold increase in
acoustic power (and a 20-dB increase is then a 100-fold increase in
power). A 10-fold increase in acoustic power does not mean that the
sound is perceived as being 10 times louder, however. Sound levels are
compared to a reference sound pressure (micro-Pascal) to identify the
medium. For air and water, these reference pressures are ``re: 20 micro
Pascals ([mu]Pa)'' and ``re: 1 [mu]Pa,'' respectively. Root mean square
(RMS) is the quadratic mean sound pressure over the duration of an
impulse. RMS is calculated by squaring all of the sound amplitudes,
averaging the squares, and then taking the square root of the average
(Urick 1975). RMS accounts for both positive and negative values;
squaring the pressures makes all values positive so that they may be
accounted for in the summation of pressure levels. This measurement is
often used in the context of discussing behavioral effects, in part
because behavioral effects, which often result from auditory cues, may
be better expressed through averaged units rather than by peak
pressures.
When sound travels (propagates) from its source, its loudness
decreases as the distance traveled by the sound increases. Thus, the
loudness of a sound at its source is higher than the loudness of that
same sound one km away. Acousticians often refer to the loudness of a
sound at its source (typically referenced to one meter from the source)
as the source level and the loudness of sound elsewhere as the received
level (i.e., typically the receiver). For example, a humpback whale 3
km from a device that has a source level of 230 dB may only be exposed
to sound that is 160 dB loud, depending on how the sound travels
through water (e.g., spherical spreading (6 dB reduction with doubling
of distance) was used in this example). As a result, it is important to
understand the difference between source levels and received levels
when discussing the loudness of sound in the ocean or its impacts on
the marine environment.
As sound travels from a source, its propagation in water is
influenced by various physical characteristics, including water
temperature, depth, salinity, and surface and bottom properties that
cause refraction, reflection, absorption, and scattering of sound
waves. Oceans are not homogeneous and the contribution of each of these
individual factors is extremely complex and interrelated. The physical
characteristics that determine the sound's speed through the water will
change with depth, season, geographic location, and with time of day
(as a result, in actual active sonar operations, crews will measure
oceanic conditions, such as sea water temperature and depth, to
calibrate models that determine the path the sonar signal will take as
it travels through the ocean and how strong the sound signal will be at
a given range along a particular transmission path). As sound travels
through the ocean, the intensity associated with the wavefront
diminishes, or attenuates. This decrease in intensity is referred to as
propagation loss, also commonly called transmission loss.
Acoustic Impacts
Geophysical surveys may temporarily impact marine mammals in the
area due to elevated in-water sound levels. Marine mammals are
continually exposed to many sources of sound. Naturally occurring
sounds such as lightning, rain, sub-sea earthquakes, and biological
sounds (e.g., snapping shrimp, whale songs) are widespread throughout
the world's oceans. Marine mammals produce sounds in various contexts
and use sound for various biological functions including, but not
limited to: (1) Social interactions; (2) foraging; (3) orientation; and
(4) predator detection. Interference with producing or receiving these
sounds may result in adverse impacts. Audible distance, or received
levels of sound depend on the nature of the sound source, ambient noise
conditions, and the sensitivity of the receptor to the sound
(Richardson et al., 1995). Type and significance of marine mammal
reactions to sound are likely dependent on a variety of factors
including, but not limited to, (1) the behavioral state of the animal
(e.g., feeding, traveling, etc.); (2) frequency of the sound; (3)
distance between the animal and the source; and (4) the level of the
sound relative to ambient conditions (Southall et al., 2007).
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. Current
data indicate that not all marine mammal species have equal hearing
capabilities (Richardson et al., 1995; Wartzok and Ketten, 1999; Au and
Hastings, 2008).
Animals are less sensitive to sounds at the outer edges of their
functional hearing range and are more sensitive to a range of
frequencies within the middle of their functional hearing range.
Hearing Impairment
Marine mammals may experience temporary or permanent hearing
[[Page 19720]]
impairment when exposed to loud sounds. Hearing impairment is
classified by temporary threshold shift (TTS) and permanent threshold
shift (PTS). PTS is considered auditory injury (Southall et al., 2007)
and occurs in a specific frequency range and amount. Irreparable damage
to the inner or outer cochlear hair cells may cause PTS; however, other
mechanisms are also involved, such as exceeding the elastic limits of
certain tissues and membranes in the middle and inner ears and
resultant changes in the chemical composition of the inner ear fluids
(Southall et al., 2007). There are no empirical data for onset of PTS
in any marine mammal; therefore, PTS-onset must be estimated from TTS-
onset measurements and from the rate of TTS growth with increasing
exposure levels above the level eliciting TTS-onset. PTS is presumed to
be likely if the hearing threshold is reduced by >=40 dB (that is, 40
dB of TTS).
Temporary Threshold Shift (TTS)
TTS is the mildest form of hearing impairment that can occur during
exposure to a loud 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, can be limited to a particular
frequency range, and can occur to varying degrees (i.e., a loss of a
certain number of dBs of sensitivity). 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.
Marine mammal hearing plays a critical role in communication with
conspecifics and in interpretation of environmental cues for purposes
such as predator avoidance and prey capture. Depending on the degree
(elevation of threshold in dB), duration (i.e., recovery time), and
frequency range of TTS and the context in which it is experienced, TTS
can have effects on marine mammals ranging from discountable to
serious. For example, a marine mammal may be able to readily compensate
for a brief, relatively small amount of TTS in a non-critical frequency
range that takes place during a time when the animals is traveling
through the open ocean, where ambient noise is lower and there are not
as many competing sounds present. Alternatively, a larger amount and
longer duration of TTS sustained during a time when communication is
critical for successful mother/calf interactions could have more
serious impacts if it were in the same frequency band as the necessary
vocalizations and of a severity that it impeded communication. The fact
that animals exposed to levels and durations of sound that would be
expected to result in this physiological response would also be
expected to have behavioral responses of a comparatively more severe or
sustained nature is also notable and potentially of more importance
than the simple existence of a TTS.
Currently, TTS data only exist for four species of cetaceans
(bottlenose dolphin, beluga whale (Delphinapterus leucas), harbor
porpoise, and Yangtze finless porpoise (Neophocaena phocaenoides)) and
three species of pinnipeds (northern elephant seal (Mirounga
angustirostris), harbor seal, and California sea lion (Zalophus
californianus)) exposed to a limited number of sound sources (i.e.,
mostly tones and octave-band noise) in laboratory settings (e.g.,
Finneran et al., 2002 and 2010; Nachtigall et al., 2004; Kastak et al.,
2005; Lucke et al., 2009; Mooney et al., 2009; Popov et al., 2011;
Finneran and Schlundt, 2010). In general, harbor seals (Kastak et al.,
2005; Kastelein et al., 2012a) and harbor porpoises (Lucke et al.,
2009; Kastelein et al., 2012b) have a lower TTS onset than other
measured pinniped or cetacean species. However, even for these animals,
which are better able to hear higher frequencies and may be more
sensitive to higher frequencies, exposures on the order of
approximately 170 dB RMS or higher for brief transient signals are
likely required for even temporary (recoverable) changes in hearing
sensitivity that would likely not be categorized as physiologically
damaging (Lucke et al., 2009). Additionally, the existing marine mammal
TTS data come from a limited number of individuals within these
species. There are no data available on noise-induced hearing loss for
mysticetes. For summaries of data on TTS in marine mammals or for
further discussion of TTS onset thresholds, please see Finneran (2015).
Scientific literature highlights the inherent complexity of
predicting TTS onset in marine mammals, as well as the importance of
considering exposure duration when assessing potential impacts (Mooney
et al., 2009a, 2009b; Kastak et al., 2007). Generally, with sound
exposures of equal energy, quieter sounds (lower sound pressure levels
(SPL)) of longer duration were found to induce TTS onset more than
louder sounds (higher SPL) of shorter duration (more similar to sub-
bottom profilers). For intermittent sounds, less threshold shift will
occur than from a continuous exposure with the same energy (some
recovery will occur between intermittent exposures) (Kryter et al.,
1966; Ward 1997). For sound exposures at or somewhat above the TTS-
onset threshold, hearing sensitivity recovers rapidly after exposure to
the sound ends; intermittent exposures recover faster in comparison
with continuous exposures of the same duration (Finneran et al., 2010).
NMFS considers TTS as Level B harassment that is mediated by
physiological effects on the auditory system.
Animals in the Lease Area during the HRG survey are unlikely to
incur TTS hearing impairment due to the characteristics of the sound
sources, which include low source levels (208 to 221 dB re 1 [micro]Pa-
m) and generally very short pulses and duration of the sound. Even for
high-frequency cetacean species (e.g., harbor porpoises), which may
have increased sensitivity to TTS (Lucke et al., 2009; Kastelein et
al., 2012b), individuals would have to make a very close approach and
also remain very close to vessels operating these sources in order to
receive multiple exposures at relatively high levels, as would be
necessary to cause TTS. Intermittent exposures--as would occur due to
the brief, transient signals produced by these sources--require a
higher cumulative SEL to induce TTS than would continuous exposures of
the same duration (i.e., intermittent exposure results in lower levels
of TTS) (Mooney et al., 2009a; Finneran et al., 2010). Moreover, most
marine mammals would more likely avoid a loud sound source rather than
swim in such close proximity as to result in TTS. Kremser et al. (2005)
noted that the probability of a cetacean swimming through the area of
exposure when a sub-bottom profiler emits a pulse is small--because 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 and would likely exhibit avoidance behavior to the area near the
transducer rather than swim through at such a close range. Further, the
restricted beam shape of the majority of the geophysical survey
equipment planned for use (Table 1) makes it unlikely that an animal
would be exposed more than briefly during the passage of the vessel.
Masking
Masking is the obscuring of sounds of interest to an animal by
other sounds, typically at similar frequencies. Marine mammals are
highly dependent on sound, and their ability to recognize sound signals
amid other sound is important in communication and
[[Page 19721]]
detection of both predators and prey (Tyack 2000). Background ambient
sound may interfere with or mask the ability of an animal to detect a
sound signal even when that signal is above its absolute hearing
threshold. Even in the absence of anthropogenic sound, the marine
environment is often loud. Natural ambient sound includes contributions
from wind, waves, precipitation, other animals, and (at frequencies
above 30 kHz) thermal sound resulting from molecular agitation
(Richardson et al., 1995).
Background sound may also include anthropogenic sound, and masking
of natural sounds can result when human activities produce high levels
of background sound. Conversely, if the background level of underwater
sound is high (e.g., on a day with strong wind and high waves), an
anthropogenic sound source would not be detectable as far away as would
be possible under quieter conditions and would itself be masked.
Ambient sound is highly variable on continental shelves (Myrberg 1978;
Desharnais et al., 1999). This results in a high degree of variability
in the range at which marine mammals can detect anthropogenic sounds.
Although masking is a phenomenon which may occur naturally, the
introduction of loud anthropogenic sounds into the marine environment
at frequencies important to marine mammals increases the severity and
frequency of occurrence of masking. For example, if a baleen whale is
exposed to continuous low-frequency sound from an industrial source,
this would reduce the size of the area around that whale within which
it can hear the calls of another whale. The components of background
noise that are similar in frequency to the signal in question primarily
determine the degree of masking of that signal. In general, little is
known about the degree to which marine mammals rely upon detection of
sounds from conspecifics, predators, prey, or other natural sources. In
the absence of specific information about the importance of detecting
these natural sounds, it is not possible to predict the impact of
masking on marine mammals (Richardson et al., 1995). In general,
masking effects are expected to be less severe when sounds are
transient than when they are continuous. Masking is typically of
greater concern for those marine mammals that utilize low-frequency
communications, such as baleen whales, because of how far low-frequency
sounds propagate.
Marine mammal communications would not likely be masked appreciably
by the sub-bottom profiler signals given the directionality of the
signals (for most geophysical survey equipment types planned for use
(Table 1)) and the brief period when an individual mammal is likely to
be within its beam.
Non-Auditory Physical Effects (Stress)
Classic stress responses begin when an animal's central nervous
system perceives a potential threat to its homeostasis. That perception
triggers stress responses regardless of whether a stimulus actually
threatens the animal; the mere perception of a threat is sufficient to
trigger a stress response (Moberg 2000; Seyle 1950). Once an animal's
central nervous system perceives a threat, it mounts a biological
response or defense that consists of a combination of the four general
biological defense responses: Behavioral responses, autonomic nervous
system responses, neuroendocrine responses, or immune responses.
In the case of many stressors, an animal's first and sometimes most
economical (in terms of biotic costs) response is behavioral avoidance
of the potential stressor or avoidance of continued exposure to a
stressor. An animal's second line of defense to stressors involves the
sympathetic part of the autonomic nervous system and the classical
``fight or flight'' response which includes the cardiovascular system,
the gastrointestinal system, the exocrine glands, and the adrenal
medulla to produce changes in heart rate, blood pressure, and
gastrointestinal activity that humans commonly associate with
``stress.'' These responses have a relatively short duration and may or
may not have significant long-term effect on an animal's welfare.
An animal's third line of defense to stressors involves its
neuroendocrine systems; the system that has received the most study has
been the hypothalamus-pituitary-adrenal system (also known as the HPA
axis in mammals). Unlike stress responses associated with the autonomic
nervous system, virtually all neuro-endocrine functions that are
affected by stress--including immune competence, reproduction,
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been
implicated in failed reproduction (Moberg 1987; Rivier 1995), altered
metabolism (Elasser et al., 2000), reduced immune competence (Blecha
2000), and behavioral disturbance. Increases in the circulation of
glucocorticosteroids (cortisol, corticosterone, and aldosterone in
marine mammals; see Romano et al., 2004) have been equated with stress
for many years.
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and distress is the biotic cost
of the response. During a stress response, an animal uses glycogen
stores that can be quickly replenished once the stress is alleviated.
In such circumstances, the cost of the stress response would not pose a
risk to the animal's welfare. However, when an animal does not have
sufficient energy reserves to satisfy the energetic costs of a stress
response, energy resources must be diverted from other biotic function,
which impairs those functions that experience the diversion. For
example, when mounting a stress response diverts energy away from
growth in young animals, those animals may experience stunted growth.
When mounting a stress response diverts energy from a fetus, an
animal's reproductive success and its fitness will suffer. In these
cases, the animals will have entered a pre-pathological or pathological
state which is called ``distress'' (Seyle 1950) or ``allostatic
loading'' (McEwen and Wingfield 2003). This pathological state will
last until the animal replenishes its biotic reserves sufficient to
restore normal function. Note that these examples involved a long-term
(days or weeks) stress response exposure to stimuli.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses have also been documented
fairly well through controlled experiments; because this physiology
exists in every vertebrate that has been studied, it is not surprising
that stress responses and their costs have been documented in both
laboratory and free-living animals (for examples see, Holberton et al.,
1996; Hood et al., 1998; Jessop et al., 2003; Krausman et al., 2004;
Lankford et al., 2005; Reneerkens et al., 2002; Thompson and Hamer,
2000). Information has also been collected on the physiological
responses of marine mammals to exposure to anthropogenic sounds (Fair
and Becker 2000; Romano et al., 2002). For example, Rolland et al.
(2012) found that noise reduction from reduced ship traffic in the Bay
of Fundy was associated with decreased stress in North Atlantic right
whales.
Studies of other marine animals and terrestrial animals would also
lead us to expect some marine mammals to experience physiological
stress responses and, perhaps, physiological responses that would be
classified as ``distress'' upon exposure to high frequency, mid-
frequency and low-
[[Page 19722]]
frequency sounds. For example, Jansen (1998) reported on the
relationship between acoustic exposures and physiological responses
that are indicative of stress responses in humans (for example,
elevated respiration and increased heart rates). Jones (1998) reported
on reductions in human performance when faced with acute, repetitive
exposures to acoustic disturbance. Trimper et al. (1998) reported on
the physiological stress responses of osprey to low-level aircraft
noise while Krausman et al. (2004) reported on the auditory and
physiology stress responses of endangered Sonoran pronghorn to military
overflights. Smith et al. (2004a, 2004b), for example, identified
noise-induced physiological transient stress responses in hearing-
specialist fish (i.e., goldfish) that accompanied short- and long-term
hearing losses. Welch and Welch (1970) reported physiological and
behavioral stress responses that accompanied damage to the inner ears
of fish and several mammals.
Hearing is one of the primary senses marine mammals use to gather
information about their environment and to communicate with
conspecifics. Although empirical information on the relationship
between sensory impairment (TTS, PTS, and acoustic masking) on marine
mammals remains limited, it seems reasonable to assume that reducing an
animal's ability to gather information about its environment and to
communicate with other members of its species would be stressful for
animals that use hearing as their primary sensory mechanism. Therefore,
we assume that acoustic exposures sufficient to trigger onset PTS or
TTS would be accompanied by physiological stress responses because
terrestrial animals exhibit those responses under similar conditions
(NRC 2003). More importantly, marine mammals might experience stress
responses at received levels lower than those necessary to trigger
onset TTS. Based on empirical studies of the time required to recover
from stress responses (Moberg 2000), we also assume that stress
responses are likely to persist beyond the time interval required for
animals to recover from TTS and might result in pathological and pre-
pathological states that would be as significant as behavioral
responses to TTS.
In general, there are few data on the potential for strong,
anthropogenic underwater sounds to cause non-auditory physical effects
in marine mammals. The available data do not allow identification of a
specific exposure level above which non-auditory effects can be
expected (Southall et al., 2007). There is no definitive evidence that
any of these effects occur even for marine mammals in close proximity
to an anthropogenic sound source. In addition, marine mammals that show
behavioral avoidance of survey vessels and related sound sources are
unlikely to incur non-auditory impairment or other physical effects.
NMFS does not expect that the generally short-term, intermittent, and
transitory HRG and geotechnical activities would create conditions of
long-term, continuous noise and chronic acoustic exposure leading to
long-term physiological stress responses in marine mammals.
Behavioral Disturbance
Behavioral disturbance may include a variety of effects, including
subtle changes in behavior (e.g., minor or brief avoidance of an area
or changes in vocalizations), more conspicuous changes in similar
behavioral activities, and more sustained and/or potentially severe
reactions, such as displacement from or abandonment of high-quality
habitat. Behavioral responses to sound are highly variable and context-
specific and any reactions depend on numerous intrinsic and extrinsic
factors (e.g., species, state of maturity, experience, current
activity, reproductive state, auditory sensitivity, time of day), as
well as the interplay between factors (e.g., Richardson et al., 1995;
Wartzok et al., 2003; Southall et al., 2007; Weilgart, 2007; Archer et
al., 2010). Behavioral reactions can vary not only among individuals
but also within an individual, depending on previous experience with a
sound source, context, and numerous other factors (Ellison et al.,
2012), and can vary depending on characteristics associated with the
sound source (e.g., whether it is moving or stationary, number of
sources, distance from the source). Please see Appendices B-C of
Southall et al. (2007) for a review of studies involving marine mammal
behavioral responses to sound.
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2003). Animals are most likely to habituate to
sounds that are predictable and unvarying. It is important to note that
habituation is appropriately considered as a ``progressive reduction in
response to stimuli that are perceived as neither aversive nor
beneficial,'' rather than as, more generally, moderation in response to
human disturbance (Bejder et al., 2009). The opposite process is
sensitization, when an unpleasant experience leads to subsequent
responses, often in the form of avoidance, at a lower level of
exposure. As noted, behavioral state may affect the type of response.
For example, animals that are resting may show greater behavioral
change in response to disturbing sound levels than animals that are
highly motivated to remain in an area for feeding (Richardson et al.,
1995; NRC 2003; Wartzok et al., 2003). Controlled experiments with
captive marine mammals have shown pronounced behavioral reactions,
including avoidance of loud sound sources (Ridgway et al., 1997;
Finneran et al., 2003). Observed responses of wild marine mammals to
loud, pulsed sound sources (typically seismic airguns or acoustic
harassment devices) have been varied but often consist of avoidance
behavior or other behavioral changes suggesting discomfort (Morton and
Symonds, 2002; see also Richardson et al., 1995; Nowacek et al., 2007).
Available studies show wide variation in response to underwater
sound; therefore, it is difficult to predict specifically how any given
sound in a particular instance might affect marine mammals perceiving
the signal. 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; NRC 2005).
However, there are broad categories of potential response, which we
describe in greater detail here, that include alteration of dive
behavior, alteration of foraging behavior, effects to breathing,
interference with or alteration of vocalization, avoidance, and flight.
Changes in dive behavior can vary widely and may consist of
increased or decreased dive times and surface intervals as well as
changes in the rates of ascent and descent during a dive (e.g., Frankel
and Clark 2000; Costa et al., 2003; Ng and Leung 2003; Nowacek et al.,
2004; Goldbogen et al., 2013a,b). Variations in dive behavior may
reflect interruptions in biologically significant activities (e.g.,
foraging) or they may be of little biological significance. The impact
of an alteration to dive behavior resulting from an acoustic exposure
depends on what the animal is doing at the time of the exposure and the
type and magnitude of the response.
[[Page 19723]]
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.,
2001; Nowacek et al.; 2004; Madsen et al., 2006; Yazvenko et al.,
2007). A determination of whether foraging disruptions incur fitness
consequences would require information on or estimates of the energetic
requirements of the affected individuals and the relationship between
prey availability, foraging effort and success, and the life history
stage of the animal.
Variations in respiration naturally vary with different behaviors
and alterations to breathing rate as a function of acoustic exposure
can be expected to co-occur with other behavioral reactions, such as a
flight response or an alteration in diving. However, respiration rates
in and of themselves may be representative of annoyance or an acute
stress response. Various studies have shown that respiration rates may
either be unaffected or could increase, depending on the species and
signal characteristics, again highlighting the importance in
understanding species differences in the tolerance of underwater noise
when determining the potential for impacts resulting from anthropogenic
sound exposure (e.g., Kastelein et al., 2001, 2005b, 2006; Gailey et
al., 2007).
Marine mammals vocalize for different purposes and across multiple
modes, such as whistling, echolocation click production, calling, and
singing. Changes in vocalization behavior in response to anthropogenic
noise can occur for any of these modes and may result from a need to
compete with an increase in background noise or may reflect increased
vigilance or a startle response. For example, in the presence of
potentially masking signals, humpback whales and killer whales have
been observed to increase the length of their songs (Miller et al.,
2000; Fristrup et al., 2003; Foote et al., 2004), while right whales
have been observed to shift the frequency content of their calls upward
while reducing the rate of calling in areas of increased anthropogenic
noise (Parks et al., 2007b). In some cases, animals may cease sound
production during production of aversive signals (Bowles et al., 1994).
Avoidance is the displacement of an individual from an area or
migration path as a result of the presence of a sound or other
stressors, and is one of the most obvious manifestations of disturbance
in marine mammals (Richardson et al., 1995). For example, gray whales
are known to change direction--deflecting from customary migratory
paths--in order to avoid noise from seismic surveys (Malme et al.,
1984). Avoidance may be short-term, with animals returning to the area
once the noise has ceased (e.g., Bowles et al., 1994; Goold 1996; Stone
et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007). Longer-
term displacement is possible, however, which may lead to changes in
abundance or distribution patterns of the affected species in the
affected region if habituation to the presence of the sound does not
occur (e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann et
al., 2006).
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
the intensity of the response (e.g., directed movement, rate of
travel). Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus, 1996). The result of a flight response could range from
brief, temporary exertion and displacement from the area where the
signal provokes flight to, in extreme cases, marine mammal strandings
(Evans and England, 2001). However, it should be noted that response to
a perceived predator does not necessarily invoke flight (Ford and
Reeves, 2008) and whether individuals are solitary or in groups may
influence the response.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other critical behaviors such as foraging or resting). These effects
have generally not been demonstrated for marine mammals, but studies
involving fish and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates (e.g., Beauchamp and
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In
addition, chronic disturbance can cause population declines through
reduction of fitness (e.g., decline in body condition) and subsequent
reduction in reproductive success, survival, or both (e.g., Harrington
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However,
Ridgway et al. (2006) reported that increased vigilance in bottlenose
dolphins exposed to sound over a five-day period did not cause any
sleep deprivation or stress effects.
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions resulting from reactions to stressors such as sound
exposure are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al., 2007).
Consequently, a behavioral response lasting less than one day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al., 2007). Note that there is a difference between multi-day
substantive behavioral reactions and multi-day anthropogenic
activities. For example, just because an activity lasts for multiple
days does not necessarily mean that individual animals are either
exposed to activity-related stressors for multiple days or, further,
exposed in a manner resulting in sustained multi-day substantive
behavioral responses.
Marine mammals are likely to avoid the HRG survey activity,
especially the naturally shy harbor porpoise, while the harbor seals
might be attracted to them out of curiosity. However, because the sub-
bottom profilers and other HRG survey equipment operate from a moving
vessel, and the maximum radius to the Level B harassment threshold is
relatively small, the area and time that this equipment would be
affecting a given location is very small. Further, once an area has
been surveyed, it is not likely that it will be surveyed again, thereby
reducing the likelihood of repeated HRG-related impacts within the
survey area.
We have also considered the potential for severe behavioral
responses such as stranding and associated indirect injury or mortality
from DWW's use of HRG survey equipment, on the basis of a 2008 mass
stranding of approximately 100 melon-headed whales in a Madagascar
lagoon system. An investigation of the event indicated that use of a
high-frequency mapping system (12-kHz multibeam echosounder) was the
most plausible and likely initial behavioral trigger of the event,
while providing the caveat that there is no unequivocal and easily
identifiable single cause (Southall et al., 2013). The investigatory
panel's conclusion was
[[Page 19724]]
based on (1) very close temporal and spatial association and directed
movement of the survey with the stranding event; (2) the unusual nature
of such an event coupled with previously documented apparent behavioral
sensitivity of the species to other sound types (Southall et al., 2006;
Brownell et al., 2009); and (3) the fact that all other possible
factors considered were determined to be unlikely causes. Specifically,
regarding survey patterns prior to the event and in relation to
bathymetry, the vessel transited in a north-south direction on the
shelf break parallel to the shore, ensonifying large areas of deep-
water habitat prior to operating intermittently in a concentrated area
offshore from the stranding site; this may have trapped the animals
between the sound source and the shore, thus driving them towards the
lagoon system. The investigatory panel systematically excluded or
deemed highly unlikely nearly all potential reasons for these animals
leaving their typical pelagic habitat for an area extremely atypical
for the species (i.e., a shallow lagoon system). Notably, this was the
first time that such a system has been associated with a stranding
event. The panel also noted several site- and situation-specific
secondary factors that may have contributed to the avoidance responses
that led to the eventual entrapment and mortality of the whales.
Specifically, shoreward-directed surface currents and elevated
chlorophyll levels in the area preceding the event may have played a
role (Southall et al., 2013). The report also notes that prior use of a
similar system in the general area may have sensitized the animals and
also concluded that, for odontocete cetaceans that hear well in higher
frequency ranges 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. It is, however, important to note that the relatively
lower output frequency, higher output power, and complex nature of the
system implicated in this event, in context of the other factors noted
here, likely produced a fairly unusual set of circumstances that
indicate that such events would likely remain rare and are not
necessarily relevant to use of lower-power, higher-frequency systems
more commonly used for HRG survey applications. The risk of similar
events recurring may be very low, given the extensive use of active
acoustic systems used for scientific and navigational purposes
worldwide on a daily basis and the lack of direct evidence of such
responses previously reported.
Tolerance
Numerous studies have shown that underwater sounds from industrial
activities are often readily detectable by marine mammals in the water
at distances of many km. However, other studies have shown that marine
mammals at distances more than a few km away often show no apparent
response to industrial activities of various types (Miller et al.,
2005). This is often true even in cases when the sounds must be readily
audible to the animals based on measured received levels and the
hearing sensitivity of that mammal group. Although various baleen
whales, toothed whales, and (less frequently) pinnipeds have been shown
to react behaviorally to underwater sound from sources such as airgun
pulses or vessels under some conditions, at other times, mammals of all
three types have shown no overt reactions (e.g., Malme et al., 1986;
Richardson et al., 1995; Madsen and Mohl 2000; Croll et al., 2001;
Jacobs and Terhune 2002; Madsen et al., 2002; Miller et al., 2005). In
general, pinnipeds seem to be more tolerant of exposure to some types
of underwater sound than are baleen whales. Richardson et al. (1995)
found that vessel sound does not seem to affect pinnipeds that are
already in the water. Richardson et al. (1995) went on to explain that
seals on haul-outs sometimes respond strongly to the presence of
vessels and at other times appear to show considerable tolerance of
vessels, and Brueggeman et al. (1992) observed ringed seals (Pusa
hispida) hauled out on ice pans displaying short-term escape reactions
when a ship approached within 0.16-0.31 miles (0.25-0.5 km). Due to the
relatively high vessel traffic in the Lease Area it is possible that
marine mammals are habituated to noise (e.g., DP thrusters) from
project vessels in the area.
Vessel Strike
Ship strikes of marine mammals 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 a vessel's propeller could injure an animal just below the
surface. 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 with known vessel speeds, 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 24.1 km/h (14.9 mph; 13 knots (kn)). Given the slow vessel
speeds and predictable course necessary for data acquisition, ship
strike is unlikely to occur during the geophysical and geotechnical
surveys. Marine mammals would be able to easily avoid the survey vessel
due to the slow vessel speed. Further, DWW would implement measures
(e.g., protected species monitoring, vessel speed restrictions and
separation distances; see Proposed Mitigation) set forth in the BOEM
lease to reduce the risk of a vessel strike to marine mammal species in
the survey area.
Marine Mammal Habitat
The HRG survey equipment will not contact the seafloor and does not
represent a source of pollution. We are not aware of any available
literature on impacts to marine mammal prey from sound produced by HRG
survey equipment. However, as the HRG survey equipment introduces noise
to the marine environment, there is the potential for it to result in
avoidance of the area around the HRG survey activities on the part of
marine mammal prey. Any avoidance of the area on the part of marine
mammal prey would be expected to be short term and temporary.
Because of the temporary nature of the disturbance, and the
availability of similar habitat and resources (e.g., prey
[[Page 19725]]
species) in the surrounding area, the impacts to marine mammals and the
food sources that they utilize are not expected to cause significant or
long-term consequences for individual marine mammals or their
populations. Impacts on marine mammal habitat from the proposed
activities will be temporary, insignificant, and discountable.
Estimated Take
This section provides an estimate of the number of incidental takes
proposed for authorization through this IHA, which will inform both
NMFS' consideration of ``small numbers'' and the negligible impact
determination.
Harassment is the only type of take expected to result from these
activities. 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).
Authorized takes would be by Level B harassment, as use of the HRG
equipment has the potential to result in disruption of behavioral
patterns for individual marine mammals. NMFS has determined take by
Level A harassment is not an expected outcome of the proposed activity
and thus we do not propose to authorize the take of any marine mammals
by Level A harassment. This is discussed in greater detail below. As
described previously, no mortality or serious injury is anticipated or
proposed to be authorized for this activity. Below we describe how the
take is estimated for this project.
Described in the most basic way, we estimate take by considering:
(1) Acoustic thresholds above which NMFS believes the best available
science indicates marine mammals will be behaviorally harassed or incur
some degree of permanent hearing impairment; (2) the area or volume of
water that will be ensonified above these levels in a day; (3) the
density or occurrence of marine mammals within these ensonified areas;
and, (4) and the number of days of activities. Below, we describe these
components in more detail and present the proposed take estimate.
Acoustic Thresholds
NMFS uses acoustic thresholds that identify the received level of
underwater sound above which exposed marine mammals would be reasonably
expected to be behaviorally harassed (equated to Level B harassment) or
to incur PTS of some degree (equated to Level A harassment).
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
sound source (e.g., frequency, predictability, duty cycle); the
environment (e.g., bathymetry); and the receiving animals (hearing,
motivation, experience, demography, behavioral context); therefore can
be difficult to predict (Southall et al., 2007, Ellison et al. 2012).
NMFS uses a generalized acoustic threshold based on received level to
estimate the onset of Level B (behavioral) harassment. NMFS predicts
that marine mammals may be behaviorally harassed when exposed to
underwater anthropogenic noise above received levels 160 dB re 1 [mu]Pa
(RMS) for non-explosive impulsive (e.g., seismic HRG equipment) or
intermittent (e.g., scientific sonar) sources. DWW's proposed activity
includes the use of impulsive sources. Therefore, the 160 dB re 1
[mu]Pa (RMS) criteria is applicable for analysis of Level B harassment.
Level A Harassment--NMFS' Technical Guidance for Assessing the
Effects of Anthropogenic Sound on Marine Mammal Hearing (NMFS 2016)
identifies dual criteria to assess auditory injury (Level A harassment)
to five different marine mammal groups (based on hearing sensitivity)
as a result of exposure to noise from two different types of sources
(impulsive or non-impulsive). The Technical Guidance identifies the
received levels, or thresholds, above which individual marine mammals
are predicted to experience changes in their hearing sensitivity for
all underwater anthropogenic sound sources, reflects the best available
science, and better predicts the potential for auditory injury than
does NMFS' historical criteria.
These thresholds were developed by compiling and synthesizing the
best available science and soliciting input multiple times from both
the public and peer reviewers to inform the final product, and are
provided in Table 3 below. The references, analysis, and methodology
used in the development of the thresholds are described in NMFS 2016
Technical Guidance, which may be accessed at: www.nmfs.noaa.gov/pr/acoustics/guidelines.htm. As described above, DWW's proposed activity
includes the use of intermittent and impulsive sources.
Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
in Marine Mammals
------------------------------------------------------------------------
PTS onset thresholds
Hearing group ------------------------------------------
Impulsive * Non-impulsive
------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans. Lpk,flat: 219 LE,LF,24h: 199 dB.
dB; LE,LF,24h:
183 dB.
Mid-Frequency (MF) Cetaceans. Lpk,flat: 230 LE,MF,24h: 198 dB.
dB; LE,MF,24h:
185 dB.
High-Frequency (HF) Cetaceans Lpk,flat: 202 LE,HF,24h: 173 dB.
dB; LE,HF,24h:
155 dB.
Phocid Pinnipeds (PW) Lpk,flat: 218 LE,PW,24h: 201 dB.
(Underwater). dB; LE,PW,24h:
185 dB.
------------------------------------------------------------------------
Note: *Dual metric acoustic thresholds for impulsive sounds: Use
whichever results in the largest isopleth for calculating PTS onset.
If a non-impulsive sound has the potential of exceeding the peak sound
pressure level thresholds associated with impulsive sounds, these
thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [mu]Pa, and
cumulative sound exposure level (LE) has a reference value of
1[mu]Pa2s. In this Table, thresholds are abbreviated to reflect
American National Standards Institute standards (ANSI 2013). However,
peak sound pressure is defined by ANSI as incorporating frequency
weighting, which is not the intent for this Technical Guidance. Hence,
the subscript ``flat'' is being included to indicate peak sound
pressure should be flat weighted or unweighted within the generalized
hearing range. The subscript associated with cumulative sound exposure
level thresholds indicates the designated marine mammal auditory
weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
and that the recommended accumulation period is 24 hours. The
cumulative sound exposure level thresholds could be exceeded in a
multitude of ways (i.e., varying exposure levels and durations, duty
cycle). When possible, it is valuable for action proponents to
indicate the conditions under which these acoustic thresholds will be
exceeded.
[[Page 19726]]
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that will feed into estimating the area ensonified above the
acoustic thresholds.
The proposed survey would entail the use of HRG survey equipment.
The distance to the isopleth corresponding to the threshold for Level B
harassment was calculated for all HRG survey equipment with the
potential to result in harassment of marine mammals using the spherical
transmission loss (TL) equation: TL = 20log10[gamma].
Results of modeling indicated that, of the HRG survey equipment planned
for use that has the potential to result in harassment of marine
mammals, the AA Dura-Spark would be expected to produce sound that
would propagate the furthest in the water (Table 4); therefore, for the
purposes of the take calculation, it was assumed the AA Dura-Spark
would be active during the entirety of the survey. Thus the distance to
the isopleth corresponding to the threshold for Level B harassment for
the AA Dura-Spark (estimated at 447 m; Table 4) was used as the basis
of the Level B take calculation for all marine mammals.
Table 4--Modeled Radial Distances From HRG Survey Equipment to Isopleths
Corresponding to Level B Harassment Threshold
------------------------------------------------------------------------
Radial
distance (m)
to Level B
HRG system harassment
threshold
(160 dB re 1
[mu]Pa)
------------------------------------------------------------------------
TB Chirp................................................ 70.79
EdgeTech Chirp.......................................... 6.31
AA Boomer............................................... 5.62
AA S-Boom............................................... 141.25
Bubble Gun.............................................. 63.1
800J Spark.............................................. 141.25
AA Dura Spark........................................... 446.69
------------------------------------------------------------------------
Predicted distances to Level A harassment isopleths, which vary
based on marine mammal functional hearing groups (Table 5), were also
calculated. The updated acoustic thresholds for impulsive sounds (such
as HRG survey equipment) contained in the Technical Guidance (NMFS,
2016) were presented as dual metric acoustic thresholds using both
cumulative sound exposure level (SELcum) and peak sound
pressure level metrics. As dual metrics, NMFS considers onset of PTS
(Level A harassment) to have occurred when either one of the two
metrics is exceeded (i.e., metric resulting in the largest isopleth).
The SELcum metric considers both level and duration of
exposure, as well as auditory weighting functions by marine mammal
hearing group. In recognition of the fact that calculating Level A
harassment ensonified areas could be more technically challenging to
predict due to the duration component and the use of weighting
functions in the new SELcum thresholds, NMFS developed an
optional User Spreadsheet that includes tools to help predict a simple
isopleth that can be used in conjunction with marine mammal density or
occurrence to facilitate the estimation of take numbers. DWW used the
NMFS optional User Spreadsheet to calculate distances to Level A
harassment isopleths based on SELcum. To calculate distances
to the Level A harassment isopleths based on peak pressure, the
spherical spreading loss model was used (similar to the method used to
calculate Level B isopleths as described above).
Modeling of distances to isopleths corresponding to Level A
harassment was performed for all types of HRG equipment planned for use
with the potential to result in harassment of marine mammals. Of the
HRG equipment types modeled, the AA Dura Spark resulted in the largest
distances to isopleths corresponding to Level A harassment for all
marine mammal functional hearing groups; therefore, to be conservative,
the isopleths modeled for the AA Dura Spark were used to estimate
potential Level A take. Based on a conservative assumption that the AA
Dura Spark would be operated at 1,000 joules during the survey, a peak
source level of 223 dB re 1[mu]Pa was used for modeling Level A
harassment isopleths based on peak pressure (Crocker & Fratantonio,
2016). Inputs to the NMFS optional User Spreadsheet for the AA Dura
Spark are shown in Table 5. Modeled distances to isopleths
corresponding to Level A harassment thresholds for the AA Dura Spark
are shown in Table 6 (modeled distances to Level A harassment isopleths
for all other types of HRG equipment planned for use are shown in Table
6 of the IHA application). As described above, NMFS considers onset of
PTS (Level A harassment) to have occurred when either one of the two
metrics is exceeded (i.e., metric resulting in the largest isopleth).
Table 5--Inputs to the NMFS Optional User Spreadsheet for the AA Dura
Spark
------------------------------------------------------------------------
------------------------------------------------------------------------
Source Level (RMS SPL) \1\................ 213 dB re 1[mu]Pa.
Source Level (peak) \1\................... 223 dB re 1[mu]Pa.
Weighting Factor Adjustment (kHz) \1\..... 3.2.
Source Velocity (meters/second)........... 2.07.
Pulse Duration (seconds).................. 0.0021.
1/Repetition rate (seconds)............... 2.42.
Duty Cycle................................ 0.00.
------------------------------------------------------------------------
\1\ Derived from Crocker & Fratantonio (2016), based on operation at
1,000 joules.
Table 6--Modeled Radial Distances to Isopleths Corresponding to Level A
Harassment Thresholds
------------------------------------------------------------------------
Radial
Radial distance (m)
distance (m) to Level A
Functional hearing group (Level A to Level A harassment
harassment thresholds) harassment threshold
threshold (Peak SPLflat)
(SELcum)
------------------------------------------------------------------------
Low frequency cetaceans................. 1.3 1.6
(Lpk,flat: 219 dB; LE,LF,24h: 183 dB)...
Mid frequency cetaceans................. 0.0 0.0
(Lpk,flat: 230 dB; LE,MF,24h: 185 dB)...
High frequency cetaceans................ 8.6 11.2
(Lpk,flat: 202 dB; LE,HF,24h: 155 dB)...
Phocid Pinnipeds (Underwater)........... 0.7 1.8
(Lpk,flat: 218 dB; LE,HF,24h: 185 dB)...
------------------------------------------------------------------------
[[Page 19727]]
Due to the small estimated distances to Level A harassment
thresholds for all marine mammal functional hearing groups, based on
both SELcum and peak SPL (Table 6), and in consideration of
the proposed mitigation measures (see the Proposed Mitigation section
for more detail), NMFS has determined that the likelihood of Level A
take of marine mammals occurring as a result of the proposed survey is
so low as to be discountable.
We note that because of some of the assumptions included in the
methods used, isopleths produced may be overestimates to some degree.
Most of the acoustic sources proposed for use in DWW's survey
(including the AA Dura-Spark) do not radiate sound equally in all
directions but were designed instead to focus acoustic energy directly
toward the sea floor. Therefore, the acoustic energy produced by these
sources is not received equally in all directions around the source but
is instead concentrated along some narrower plane depending on the
beamwidth of the source. However, the calculated distances to isopleths
do not account for this directionality of the sound source and are
therefore conservative. Two types of geophysical survey equipment
planned for use in the proposed survey are omni-directional (Table 1),
however the modeled distances to isopleths corresponding to the Level B
harassment threshold for these sources are smaller than that for the
Dura Spark (Table 1), and the Dura Spark was used to conservatively
estimate take for the duration of the survey. For mobile sources, such
as the proposed survey, the User Spreadsheet predicts the closest
distance at which a stationary animal would not incur PTS if the sound
source traveled by the animal in a straight line at a constant speed.
Marine Mammal Occurrence
In this section we provide the information about the presence,
density, or group dynamics of marine mammals that will inform the take
calculations.
The best available scientific information was considered in
calculating marine mammal exposure estimates (the basis for estimating
take). For cetacean species, densities calculated by Roberts et al.
(2016) were used. The density data presented by Roberts et al. (2016)
incorporates aerial and shipboard line-transect survey data from NMFS
and from other organizations collected over the period 1992-2014.
Roberts et al. (2016) modeled density from 8 physiographic and 16
dynamic oceanographic and biological covariates, and controlled for the
influence of sea state, group size, availability bias, and perception
bias on the probability of making a sighting. NMFS considers the models
produced by Roberts et al. (2016) to be the best available source of
data regarding cetacean densities for this project. More information,
including the model results and supplementary information for each
model, is available online at: seamap.env.duke.edu/models/Duke-EC-GOM-2015/.
For the purposes of the take calculations, density data from
Roberts et al. (2016) were mapped using a geographic information system
(GIS), using density data for the months June through December. Mean
density per month for each species within the survey area was
calculated by selecting 13 random raster cells selected from 100 km\2\
raster cells that were inside, or adjacent to, the RI-MA WEA (see
Figure 1 in the IHA application). Estimates provided by the models are
based on a grid cell size of 100 km\2\; therefore, model grid cell
values were then divided by 100 to determine animals per square km.
Systematic, offshore, at-sea survey data for pinnipeds are more
limited than those for cetaceans. The best available information
concerning pinniped densities in the proposed survey area is the U.S.
Navy's Operating Area (OPAREA) Density Estimates (NODEs) (DoN, 2007).
These density models utilized vessel-based and aerial survey data
collected by NMFS from 1998-2005 during broad-scale abundance studies.
Modeling methodology is detailed in DoN (2007). For the purposes of the
take calculations, NODEs Density Estimates (DoN, 2007) as reported for
the summer and fall seasons were used to estimate harbor seal and gray
seal densities.
Take Calculation and Estimation
Here we describe how the information provided above is brought
together to produce a quantitative take estimate.
In order to estimate the number of marine mammals predicted to be
exposed to sound levels that would result in harassment, radial
distances to predicted isopleths corresponding to harassment thresholds
are calculated, as described above. Those distances are then used to
calculate the area(s) around the HRG survey equipment predicted to be
ensonified to sound levels that exceed harassment thresholds. The area
estimated to be ensonified to relevant thresholds in a single day of
the survey is then calculated, based on areas predicted to be
ensonified around the HRG survey equipment and the estimated trackline
distance traveled per day by the survey vessel. DWW estimates a maximum
daily track line distance of 110 km per day during HRG surveys. Based
on the maximum estimated distance to the Level B harassment threshold
of 447 m (Table 4) and the maximum estimated daily track line distance
of 110 km, an area of 98.9 km\2\ would be ensonified to the Level B
harassment threshold per day during HRG surveys.
The number of marine mammals expected to be incidentally taken per
day is then calculated by estimating the number of each species
predicted to occur within the daily ensonified area, using estimated
marine mammal densities as described above. Estimated numbers of each
species taken per day are then multiplied by the number of survey days
(i.e., 200), and the product is then rounded, to generate an estimate
of the total number of each species expected to be taken over the
duration of the survey (Table 7).
The applicant estimated a total of 11 takes by Level A harassment
of harbor porpoises, 5 takes by Level A harassment of harbor seals, and
7 takes by Level A harassment of gray seals would occur, in the absence
of mitigation. However, as described above, due to the very small
estimated distances to Level A harassment thresholds (Table 6), and in
consideration of the proposed mitigation measures, the likelihood of
the proposed survey resulting in take in the form of Level A harassment
is considered so low as to be discountable; therefore, we do not
propose to authorize take of any marine mammals by Level A harassment.
Although there are no exclusion zones (EZs) proposed for pinnipeds, the
estimated distance to the isopleth corresponding to the Level A
harassment threshold for pinnipeds is less than 2 m (Table 6);
therefore, we determined the likelihood of an animal being taken within
this proximity of the survey equipment to be so low as to be
discountable. Proposed take numbers are shown in Table 7.
[[Page 19728]]
Table 7--Total Numbers of Potential Incidental Take of Marine Mammals Proposed for Authorization and Proposed Takes as a Percentage of Population
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total proposed
Density (#/100 Proposed Level Estimated Proposed Level Total Proposed takes as a
Species km\2\) A takes Level B takes B takes takes percentage of
population \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale............................ 0.01706 0 3 3 3 0.6
Humpback whale........................................ 0.14439 0 29 29 29 1.8
Fin whale \2\......................................... 0.21353 0 42 42 42 1.2
Sei whale \3\......................................... 0.005 0 1 2 2 0.3
Minke whale........................................... 0.04745 0 9 9 9 <0.1
Sperm whale........................................... 0.00665 0 1 1 1 <0.1
Long-finned pilot whale \3\........................... 0.15364 0 30 32 32 0.2
Bottlenose dolphin.................................... 1.60936 0 318 318 318 0.3
Atlantic Spotted dolphin \3\.......................... 0.00886 0 2 50 50 0.1
Common dolphin \2\.................................... 4.59986 0 910 910 910 0.5
Atlantic white-sided dolphin.......................... 1.8036 0 357 357 357 1.0
Harbor porpoise \4\................................... 2.53125 0 501 501 501 1.1
Harbor seal........................................... 6.49533 0 1,285 1,285 1,285 1.7
Gray seal............................................. 9.41067 0 1,861 1,861 1,861 6.9
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Estimates of total proposed takes as a percentage of population are based on marine mammal abundance estimates provided by Roberts et al. (2016),
when available, except where noted otherwise, to maintain consistency with density estimates which are derived from data provided by Roberts et al.
(2016). In cases where abundances are not provided by Roberts et al. (2016), total proposed takes as a percentage of population are based on abundance
estimates in the NMFS Atlantic SARs (Hayes et al., 2018).
\2\ Estimates of total proposed takes as a percentage of population are based on marine mammal abundance estimates as reported in the 2007 TNASS (Lawson
and Gosselin, 2009) (Table 2). Abundance estimates from TNASS were corrected for perception and availability bias, when possible. In general, where
the TNASS survey effort provided superior coverage of a stock's range (as compared with NOAA shipboard survey effort), the resulting abundance
estimate is considered more accurate than abundance estimates based on NMFS surveys.
\3\ The proposed number of authorized takes (Level B harassment only) for these species has been increased from the estimated take to mean group size.
Source for sei whale group size estimate is: Schilling et al. (1992). Source for long-finned pilot whale group size estimate is: Augusto et al.
(2017). Source for Atlantic spotted dolphin group size estimate is: Jefferson et al. (2008).
\4\ The density estimate in the IHA application is incorrectly shown as 0.0225781 animals/km2. The correct density estimate is reflected in Table 7.
Species with Take Estimates Less than Mean Group Size: Using the
approach described above to estimate take, the take estimates for the
sei whale, long-finned pilot whale and Atlantic spotted dolphin were
less than the average group sizes estimated for these species (Table
6). However, information on the social structures and life histories of
these species indicates these species are often encountered in groups.
The results of take calculations support the likelihood that the
proposed survey is expected to encounter and to incidentally take these
species, and we believe it is likely that these species may be
encountered in groups. Therefore it is reasonable to conservatively
assume that one group of each of these species will be taken during the
proposed survey. We propose to authorize the take of the average group
size for these species and stocks to account for the possibility that
the proposed survey encounters a group of any of these species or
stocks (Table 7). Note that the take estimate for the sperm whale was
not increased to average group size because, based on water depths in
the proposed survey area (16 to 28 m (52 to 92 ft)), it is very
unlikely that groups of sperm whales, which tend to prefer deeper
depths, would be encountered by the proposed survey.
Proposed Mitigation
In order to issue an IHA 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 on
the availability of such species or stock for taking for certain
subsistence uses (latter not applicable for this action). NMFS
regulations require applicants for incidental take authorizations to
include information about the availability and feasibility (economic
and technological) of equipment, methods, and manner of conducting such
activity or other means of effecting the least practicable adverse
impact upon the affected species or stocks and their habitat (50 CFR
216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, we
carefully consider two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat.
This considers the nature of the potential adverse impact being
mitigated (likelihood, scope, range). It further considers the
likelihood that the measure will be effective if implemented
(probability of accomplishing the mitigating result if implemented as
planned) the likelihood of effective implementation (probability
implemented as planned): and
(2) The practicability of the measures for applicant
implementation, which may consider such things as relative cost and
impact on operations.
Proposed Mitigation Measures
With NMFS' input during the application process, and as per the
BOEM Lease, DWW is proposing the following mitigation measures during
the proposed marine site characterization surveys.
Marine Mammal Exclusion and Watch Zones
Marine mammal exclusion zones (EZ) will be established around the
HRG survey equipment and monitored by protected species observers (PSO)
during HRG surveys as follows:
500 m EZ for North Atlantic right whales;
200 m EZ for all other ESA-listed cetaceans (including fin
whale, sei whale and sperm whale); and
[[Page 19729]]
25 m EZ for harbor porpoises.
The applicant proposed a 500 m EZ for North Atlantic right whales
and 200 m EZ for all other marine mammal species; however, for non-ESA-
listed marine mammals, based on estimated distances to isopleths
corresponding with Level A harassment thresholds (Table 5), we
determined EZs for species other than those described above were not
warranted. In addition to the EZs described above, PSOs will visually
monitor and record the presence of all marine mammals within 500 m.
Visual Monitoring
As per the BOEM lease, visual and acoustic monitoring of the
established exclusion and monitoring zones will be performed by four
qualified and NMFS-approved PSOs. It would be the responsibility of the
Lead PSO on duty to communicate the presence of marine mammals as well
as to communicate and enforce the action(s) that are necessary to
ensure mitigation and monitoring requirements are implemented as
appropriate. PSOs would be equipped with binoculars and would estimate
distances to marine mammals located in proximity to the vessel and/or
exclusion zone using range finders. Reticulated binoculars would also
be available to PSOs for use as appropriate based on conditions and
visibility to support the siting and monitoring of marine species.
Position data will be recorded using hand-held or vessel global
positioning system (GPS) units for each sighting. Observations will
take place from the highest available vantage point on the survey
vessel. During surveys conducted at night, night-vision equipment with
infrared light-emitting diodes spotlights and/or infrared video
monitoring will be available for PSO use, and passive acoustic
monitoring (PAM; described below) will be used (as required per the
BOEM lease).
Pre-Clearance of the Exclusion Zone
Prior to initiating HRG survey activities, DWW would implement a
30-minute pre-clearance period. During this period, the PSOs would
ensure that no marine mammals are observed within 200 m of the survey
equipment (500 m in the case of North Atlantic right whales). Survey
equipment would not start up until this 200 m zone (or, 500 m zone in
the case of North Atlantic right whales) is clear of marine mammals for
at least 30 minutes. This pre-clearance requirement would include small
delphinoids that approach the vessel (e.g., bow ride). PSOs would also
continue to monitor the zone for 30 minutes after survey equipment is
shut down or survey activity has concluded.
Passive Acoustic Monitoring
As proposed by the applicant and required by the BOEM lease, PAM
will be used to support monitoring during night time operations to
provide for optimal acquisition of species detections at night. The PAM
system will consist of an array of hydrophones with both broadband
(sampling mid-range frequencies of 2 kHz to 200 kHz) and at least one
low-frequency hydrophone (sampling range frequencies of 75 Hz to 30
kHz). The PAM operator(s) will monitor acoustic signals in real time
both aurally (using headphones) and visually (via sound analysis
software). PAM operators will communicate nighttime detections to the
lead PSO on duty who will ensure the implementation of the appropriate
mitigation measure. However, PAM detection alone would not trigger a
requirement that any mitigation action be taken upon acoustic detection
of marine mammals.
Ramp-Up of Survey Equipment
As proposed by the applicant, where technically feasible, a ramp-up
procedure would be used for geophysical survey equipment capable of
adjusting energy levels at the start or re-start of survey activities.
The ramp-up procedure would be used at the beginning of HRG survey
activities in order to provide additional protection to marine mammals
near the survey area by allowing them to detect the presence of the
survey and vacate the area prior to the commencement of survey
equipment use at full energy. Ramp-up of the survey equipment would not
begin until the relevant EZ has been cleared by the PSOs, as described
above. Systems will be initiated at their lowest power output and will
be incrementally increased to full power. If any marine mammals are
detected within the EZ prior to or during the ramp-up, HRG equipment
will be shut down (as described below).
Shutdown Procedures
As required in the BOEM lease, if a marine mammal is observed
within or approaching the relevant EZ (as described above) an immediate
shutdown of the survey equipment is required. Subsequent restart of the
survey equipment may only occur after the animal(s) has either been
observed exiting the relevant EZ or until an additional time period has
elapsed with no further sighting of the animal (e.g., 15 minutes for
harbor porpoise and 30 minutes for North Atlantic right whale, fin
whale, sei whale and sperm whale).
As required in the BOEM lease, if the HRG equipment shuts down for
reasons other than mitigation (i.e., mechanical or electronic failure)
resulting in the cessation of the survey equipment for a period greater
than 20 minutes, a 30 minute pre-clearance period (as described above)
would precede the restart of the HRG survey equipment. If the pause is
less than less than 20 minutes, the equipment may be restarted as soon
as practicable at its full operational level only if visual surveys
were continued diligently throughout the silent period and the EZs
remained clear of marine mammals during that entire period. If visual
surveys were not continued diligently during the pause of 20 minutes or
less, a 30-minute pre-clearance period (as described above) would
precede the re-start of the HRG survey equipment. Following a shutdown,
HRG survey equipment may be restarted following pre-clearance of the
zones as described above.
If a species for which authorization has not been granted, or, a
species for which authorization has been granted but the authorized
number of takes have been met, approaches or is observed within the
area encompassing the Level B harassment isopleth (450 m), shutdown
would occur.
Vessel Strike Avoidance
Vessel strike avoidance measures will include, but are not limited
to, the following, as required in the BOEM lease, except under
circumstances when complying with these requirements would put the
safety of the vessel or crew at risk:
All vessel operators and crew will maintain vigilant watch
for cetaceans and pinnipeds, and slow down or stop their vessel to
avoid striking these protected species;
All vessel operators will comply with 10 knot (18.5 km/hr)
or less speed restrictions in any SMA and DMA per NOAA guidance;
All vessel operators will reduce vessel speed to 10 knots
(18.5 km/hr) or less when any large whale, any mother/calf pairs, large
assemblages of non-delphinoid cetaceans are observed near (within 100 m
(330 ft)) an underway vessel;
All survey vessels will maintain a separation distance of
500 m (1640 ft) or greater from any sighted North Atlantic right whale;
If underway, vessels must steer a course away from any
sighted North Atlantic right whale at 10 knots (18.5 km/hr) or less
until the 500 m (1640 ft) minimum separation distance has been
[[Page 19730]]
established. If a North Atlantic right whale is sighted in a vessel's
path, or within 100 m (330 ft) to an underway vessel, the underway
vessel must reduce speed and shift the engine to neutral. Engines will
not be engaged until the North Atlantic right whale has moved outside
of the vessel's path and beyond 100 m. If stationary, the vessel must
not engage engines until the North Atlantic right whale has moved
beyond 100 m;
All vessels will maintain a separation distance of 100 m
(330 ft) or greater from any sighted non-delphinoid cetacean. If
sighted, the vessel underway must reduce speed and shift the engine to
neutral, and must not engage the engines until the non-delphinoid
cetacean has moved outside of the vessel's path and beyond 100 m. If a
survey vessel is stationary, the vessel will not engage engines until
the non-delphinoid cetacean has moved out of the vessel's path and
beyond 100 m;
All vessels will maintain a separation distance of 50 m
(164 ft) or greater from any sighted delphinoid cetacean. Any vessel
underway remain parallel to a sighted delphinoid cetacean's course
whenever possible, and avoid excessive speed or abrupt changes in
direction. Any vessel underway reduces vessel speed to 10 knots (18.5
km/hr) or less when pods (including mother/calf pairs) or large
assemblages of delphinoid cetaceans are observed. Vessels may not
adjust course and speed until the delphinoid cetaceans have moved
beyond 50 m and/or the abeam of the underway vessel;
All vessels will maintain a separation distance of 50 m
(164 ft) or greater from any sighted pinniped; and
All vessels underway will not divert or alter course in
order to approach any whale, delphinoid cetacean, or pinniped. Any
vessel underway will avoid excessive speed or abrupt changes in
direction to avoid injury to the sighted cetacean or pinniped.
DWW will ensure that vessel operators and crew maintain a vigilant
watch for cetaceans and pinnipeds by slowing down or stopping the
vessel to avoid striking marine mammals. Project-specific training will
be conducted for all vessel crew prior to the start of the site
characterization survey activities. Confirmation of the training and
understanding of the requirements will be documented on a training
course log sheet. Signing the log sheet will certify that the crew
members understand and will comply with the necessary requirements
throughout the survey activities.
Seasonal Operating Requirements
As described above, the northern section of the proposed survey
area partially overlaps with a portion of a North Atlantic right whale
SMA which occurs east of Long Island, New York, and south of
Massachusetts and Rhode Island. This SMA is active from November 1
through April 30 of each year. Survey vessels that are >65 ft in length
would be required to adhere to the mandatory vessel speed restrictions
(<10 kn) when operating within the SMA during times when the SMA is
active. In addition, between watch shifts, members of the monitoring
team would consult NMFS' North Atlantic right whale reporting systems
for the presence of North Atlantic right whales throughout survey
operations. Members of the monitoring team would monitor the NMFS North
Atlantic right whale reporting systems for the establishment of a
Dynamic Management Area (DMA). If NMFS should establish a DMA in the
survey area, within 24 hours of the establishment of the DMA DWW would
coordinate with NMFS to shut down and/or alter the survey activities as
needed to avoid right whales to the extent possible.
The proposed mitigation measures are designed to avoid the already
low potential for injury in addition to some Level B harassment, and to
minimize the potential for vessel strikes. There are no known marine
mammal rookeries or mating grounds in the survey area that would
otherwise potentially warrant increased mitigation measures for marine
mammals or their habitat (or both). The proposed survey would occur in
an area that has been identified as a biologically important area for
migration for North Atlantic right whales. However, given the small
spatial extent of the survey area relative to the substantially larger
spatial extent of the right whale migratory area, the survey is not
expected to appreciably reduce migratory habitat nor to negatively
impact the migration of North Atlantic right whales, thus mitigation to
address the proposed survey's occurrence in North Atlantic right whale
migratory habitat is not warranted. The proposed survey area would
partially overlap spatially with a biologically important feeding area
for fin whales. However, the fin whale feeding area is sufficiently
large (2,933 km\2\), and the acoustic footprint of the proposed survey
is sufficiently small (<100 km\2\ estimated to be ensonified to the
Level B harassment threshold per day), that the survey is not expected
to appreciably reduce fin whale feeding habitat nor to negatively
impact the feeding of fin whales, thus mitigation to address the
proposed survey's occurrence in fin whale feeding habitat is not
warranted. Further, we believe the proposed mitigation measures are
practicable for the applicant to implement.
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined that the proposed mitigation measures
provide the means of effecting the least practicable impact on the
affected 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 IHA 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
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present in the
proposed action area. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) Action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the action; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of individual
[[Page 19731]]
marine mammals; or (2) populations, species, or stocks;
Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and
Mitigation and monitoring effectiveness.
Proposed Monitoring Measures
As described above, visual monitoring of the EZs and monitoring
zone will be performed by qualified and NMFS-approved PSOs. Observer
qualifications would include completion of a PSO training course and
documented field experience on a marine mammal observation vessel and/
or aerial surveys. As proposed by the applicant and required by BOEM,
an observer team comprising a minimum of four NMFS-approved PSOs and a
minimum of two certified PAM operator(s), operating in shifts, will be
employed by DWW during the proposed surveys. PSOs and PAM operators
will work in shifts such that no one monitor will work more than 4
consecutive hours without a 2 hour break or longer than 12 hours during
any 24-hour period. During daylight hours the PSOs will rotate in
shifts of one on and three off, while during nighttime operations PSOs
will work in pairs. The PAM operators will also be on call as necessary
during daytime operations should visual observations become impaired.
Each PSO will monitor 360 degrees of the field of vision. DWW will
provide r[eacute]sum[eacute]s of all proposed PSOs and PAM operators
(including alternates) to NMFS for review and approval at least 45 days
prior to the start of survey operations.
Also as described above, PSOs will be equipped with binoculars and
have the ability to estimate distances to marine mammals located in
proximity to the vessel and/or exclusion zone using range finders.
Reticulated binoculars will also be available to PSOs for use as
appropriate based on conditions and visibility to support the sighting
and monitoring of marine species. During night operations, PAM and
night-vision equipment with infrared light-emitting diode spotlights
and/or infrared video monitoring will be used to increase the ability
to detect marine mammals. Position data will be recorded using hand-
held or vessel global positioning system (GPS) units for each sighting.
Observations will take place from the highest available vantage point
on the survey vessel. General 360-degree scanning will occur during the
monitoring periods, and target scanning by the PSO will occur when
alerted of a marine mammal presence.
Data on all PAM/PSO observations will be recorded based on standard
PSO collection requirements. This will include dates, times, and
locations of survey operations; time of observation, location and
weather; details of marine mammal sightings (e.g., species, numbers,
behavior); and details of any observed taking (e.g., behavioral
disturbances or injury/mortality).
Proposed Reporting Measures
Within 90 days after completion of survey activities, a final
technical report will be provided to NMFS that fully documents the
methods and monitoring protocols, summarizes the data recorded during
monitoring, summarizes the number of marine mammals estimated to have
been taken during survey activities (by species, when known),
summarizes the mitigation actions taken during surveys (including what
type of mitigation and the species and number of animals that prompted
the mitigation action, when known), and provides an interpretation of
the results and effectiveness of all mitigation and monitoring. Any
recommendations made by NMFS must be addressed in the final report
prior to acceptance by NMFS.
In addition to the final technical report, DWW will provide the
reports described below as necessary during survey activities. In the
unanticipated event that DWW's survey activities lead to an injury
(Level A harassment) or mortality (e.g., ship-strike, gear interaction,
and/or entanglement) of a marine mammal, DWW would immediately cease
the specified activities and report the incident to the Chief of the
Permits and Conservation Division, Office of Protected Resources and
the NMFS Greater Atlantic Stranding Coordinator. The report would
include the following information:
Time, date, and location (latitude/longitude) of the
incident;
Name and type of vessel involved;
Vessel's speed during and leading up to the incident;
Description of the incident;
Status of all sound source use in the 24 hours preceding
the incident;
Water depth;
Environmental conditions (e.g., wind speed and direction,
Beaufort sea state, cloud cover, and visibility);
Description of all marine mammal observations in the 24
hours preceding the incident;
Species identification or description of the animal(s)
involved;
Fate of the animal(s); and
Photographs or video footage of the animal(s) (if
equipment is available).
Activities would not resume until NMFS is able to review the
circumstances of the event. NMFS would work with DWW to minimize
reoccurrence of such an event in the future. DWW would not resume
activities until notified by NMFS.
In the event that DWW discovers an injured or dead marine mammal
and 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), DWW would immediately report the incident to the Chief
of the Permits and Conservation Division, Office of Protected Resources
and the NMFS Greater Atlantic Stranding Coordinator. The report would
include the same information identified in the paragraph above.
Activities would be able to continue while NMFS reviews the
circumstances of the incident. NMFS would work with DWW to determine if
modifications in the activities are appropriate.
In the event that DWW discovers an injured or dead marine mammal
and determines that the injury or death is not associated with or
related to the activities authorized in the IHA (e.g., previously
wounded animal, carcass with moderate to advanced decomposition, or
scavenger damage), DWW would report the incident to the Chief of the
Permits and Conservation Division, Office of Protected Resources, and
the NMFS Greater Atlantic Regional Stranding Coordinator, within 24
hours of the discovery. DWW would provide photographs or video footage
(if available) or other documentation of the stranded animal sighting
to NMFS. DWW may continue its operations under such a case.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact 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. 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 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 harassment, NMFS considers other factors, such as the likely
nature of any responses (e.g.,
[[Page 19732]]
intensity, duration), the context of any responses (e.g., critical
reproductive time or location, migration), as well as effects on
habitat, and the likely effectiveness of the mitigation. We also assess
the number, intensity, and context of estimated takes by evaluating
this information relative to population status. Consistent with the
1989 preamble for NMFS's implementing regulations (54 FR 40338;
September 29, 1989), the impacts from other past and ongoing
anthropogenic activities are incorporated into this analysis via their
impacts on the environmental baseline (e.g., as reflected in the
regulatory status of the species, population size and growth rate where
known, ongoing sources of human-caused mortality, or ambient noise
levels).
To avoid repetition, our analysis applies to all the species listed
in Table 7, given that NMFS expects the anticipated effects of the
proposed survey to be similar in nature.
NMFS does not anticipate that serious injury or mortality would
occur as a result of DWW's proposed survey, even in the absence of
proposed mitigation. Thus the proposed authorization does not authorize
any serious injury or mortality. As discussed in the Potential Effects
section, non-auditory physical effects and vessel strike are not
expected to occur.
We expect that all potential takes would be in the form of short-
term Level B behavioral harassment in the form of temporary avoidance
of the area or decreased foraging (if such activity were occurring),
reactions that are considered to be of low severity and with no lasting
biological consequences (e.g., Southall et al., 2007).
Potential impacts to marine mammal habitat were discussed
previously in this document (see Potential Effects of the Specified
Activity on Marine Mammals and their Habitat). Marine mammal habitat
may be impacted by elevated sound levels, but these impacts would be
temporary. In addition to being temporary and short in overall
duration, the acoustic footprint of the proposed survey is small
relative to the overall distribution of the animals in the area and
their use of the area. Feeding behavior is not likely to be
significantly impacted. Prey species are mobile and are broadly
distributed throughout the project area; therefore, marine mammals that
may be temporarily displaced during survey activities are expected to
be able to resume foraging once they have moved away from areas with
disturbing levels of underwater noise. Because of the temporary nature
of the disturbance and the availability of similar habitat and
resources in the surrounding area, the impacts to marine mammals and
the food sources that they utilize are not expected to cause
significant or long-term consequences for individual marine mammals or
their populations.
There are no rookeries or mating grounds known to be biologically
important to marine mammals within the proposed survey area. As
described above, the proposed survey area would overlap spatially and
temporally with a biologically important feeding area for fin whales.
The important fin whale feeding area occurs from March through October
and stretches from an area south of Montauk Point to south of Martha's
Vineyard. However, the fin whale feeding area is sufficiently large
(2,933 km\2\), and the acoustic footprint of the proposed survey is
sufficiently small (<100 km\2\ estimated to be ensonified to the Level
B harassment threshold per day), that fin whale feeding habitat would
not be reduced appreciably. Any fin whales temporarily displaced from
the proposed survey area would be expected to have sufficient remaining
feeding habitat available to them, and would not be prevented from
feeding in other areas within the biologically important feeding
habitat. In addition, any displacement of fin whales from the survey
area would be expected to be temporary in nature. Therefore, we do not
expect fin whale feeding to be negatively impacted by the proposed
survey. There are no feeding areas known to be biologically important
to marine mammals within the proposed project area with the exception
of the aforementioned feeding area for fin whales. There is no
designated critical habitat for any ESA-listed marine mammals in the
proposed survey area.
The proposed survey area is within a biologically important
migratory area for North Atlantic right whales (effective March-April
and November-December) that extends from Massachusetts to Florida
(LaBrecque, et al., 2015). Off the south coast of Massachusetts and
Rhode Island, this biologically important migratory area extends from
the coast to beyond the shelf break. Due to the fact that that the
proposed survey is temporary and short in overall duration, and the
fact that the spatial acoustic footprint of the proposed survey is very
small relative to the spatial extent of the available migratory habitat
in the area, right whale migration is not expected to be impacted by
the proposed survey.
The proposed mitigation measures are expected to reduce the number
and/or severity of takes by (1) giving animals the opportunity to move
away from the sound source before HRG survey equipment reaches full
energy; (2) preventing animals from being exposed to sound levels that
may otherwise result in injury. Additional vessel strike avoidance
requirements will further mitigate potential impacts to marine mammals
during vessel transit to and within the survey area.
NMFS concludes that exposures to marine mammal species and stocks
due to DWW's proposed survey would result in only short-term (temporary
and short in duration) effects to individuals exposed. Marine mammals
may temporarily avoid the immediate area, but are not expected to
permanently abandon the area. Major shifts in habitat use,
distribution, or foraging success are not expected. NMFS does not
anticipate the proposed take estimates to impact annual rates of
recruitment or survival.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect the species or stock
through effects on annual rates of recruitment or survival:
No mortality, serious injury, or Level A harassment is
anticipated or authorized;
The anticipated impacts of the proposed activity on marine
mammals would be temporary behavioral changes due to avoidance of the
area around the survey vessel;
The availability of alternate areas of similar habitat
value for marine mammals to temporarily vacate the survey area during
the proposed survey to avoid exposure to sounds from the activity;
The proposed project area does not contain areas of
significance for mating or calving;
Effects on species that serve as prey species for marine
mammals from the proposed survey would be temporary and would not be
expected to reduce the availability of prey or to affect marine mammal
feeding;
The proposed mitigation measures, including visual and
acoustic monitoring, exclusion zones, and shutdown measures, are
expected to minimize potential 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 the proposed activity will have a negligible impact on
all affected marine mammal species or stocks.
[[Page 19733]]
Small Numbers
As noted above, only small numbers of incidental take may be
authorized under Section 101(a)(5)(D) of the MMPA for specified
activities other than military readiness activities. The MMPA does not
define small numbers and so, in practice, where estimated numbers are
available, NMFS compares the number of individuals taken to the most
appropriate estimation of abundance of the relevant species or stock in
our determination of whether an authorization is limited to small
numbers of marine mammals. Additionally, other qualitative factors may
be considered in the analysis, such as the temporal or spatial scale of
the activities.
The numbers of marine mammals that we propose for authorization to
be taken, for all species and stocks, would be considered small
relative to the relevant stocks or populations (less than 7 percent of
each species and stocks). See Table 7. Based on the analysis contained
herein of the proposed activity (including the proposed mitigation and
monitoring measures) and the anticipated take of marine mammals, NMFS
preliminarily finds that small numbers of marine mammals will be taken
relative to the population size of the affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
There are no relevant subsistence uses of the affected marine
mammal stocks or species 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.
Endangered Species Act
Section 7(a)(2) of the Endangered Species Act of 1973 (16 U.S.C.
1531 et seq.) requires that each Federal agency insure that any action
it authorizes, funds, or carries out is not likely to jeopardize the
continued existence of any endangered or threatened species or result
in the destruction or adverse modification of designated critical
habitat. To ensure ESA compliance for the issuance of IHAs, NMFS
consults internally, in this case with the NMFS Greater Atlantic
Regional Fisheries Office (GARFO), whenever we propose to authorize
take for endangered or threatened species.
The NMFS Office of Protected Resources is proposing to authorize
the incidental take of four species of marine mammals which are listed
under the ESA: The North Atlantic right, fin, sei, and sperm whale.
BOEM consulted with NMFS GARFO under section 7 of the ESA on commercial
wind lease issuance and site assessment activities on the Atlantic
Outer Continental Shelf in Massachusetts, Rhode Island, New York and
New Jersey Wind Energy Areas. NMFS GARFO issued a Biological Opinion
concluding that these activities may adversely affect but are not
likely to jeopardize the continued existence of the North Atlantic
right, fin, and sperm whale. The Biological Opinion can be found online
at: www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable. NMFS
will conclude the ESA section 7 consultation prior to reaching a
determination regarding the proposed issuance of the authorization. If
the IHA is issued, the Biological Opinion may be amended to include an
incidental take statement for these marine mammal species, as
appropriate.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to DWW for conducting marine site assessment surveys
offshore Massachusetts and Rhode Island and along potential submarine
cable routes from the date of issuance for a period of one year,
provided the previously mentioned mitigation, monitoring, and reporting
requirements are incorporated. This section contains a draft of the IHA
itself. The wording contained in this section is proposed for inclusion
in the IHA (if issued).
1. This IHA is valid for a period of one year from the date of
issuance.
2. This IHA is valid only for marine site characterization survey
activity, as specified in the IHA application, in the Atlantic Ocean.
3. General Conditions
(a) A copy of this IHA must be in the possession of DWW, the vessel
operator and other relevant personnel, the lead PSO, and any other
relevant designees of DWW operating under the authority of this IHA.
(b) The species authorized for taking are listed in Table 6. The
taking, by Level B harassment only, is limited to the species and
numbers listed in Table 6. Any taking of species not listed in Table 6,
or exceeding the authorized amounts listed in Table 6, is prohibited
and may result in the modification, suspension, or revocation of this
IHA.
(c) The taking by injury, serious injury or death of any species of
marine mammal is prohibited and may result in the modification,
suspension, or revocation of this IHA.
(d) DWW shall ensure that the vessel operator and other relevant
vessel personnel are briefed on all responsibilities, communication
procedures, marine mammal monitoring protocols, operational procedures,
and IHA requirements prior to the start of survey activity, and when
relevant new personnel join the survey operations.
4. Mitigation Requirements--the holder of this Authorization is
required to implement the following mitigation measures:
(a) DWW shall use at least four (4) NMFS-approved protected species
observers (PSOs) during HRG surveys. The PSOs must have no tasks other
than to conduct observational effort, record observational data, and
communicate with and instruct relevant vessel crew with regard to the
presence of marine mammals and mitigation requirements. PSO resumes
shall be provided to NMFS for approval prior to commencement of the
survey.
(b) Visual monitoring must begin no less than 30 minutes prior to
initiation of survey equipment and must continue until 30 minutes after
use of survey equipment ceases.
(c) Exclusion Zones--PSOs shall establish and monitor marine mammal
Exclusion Zones and Watch Zone. Exclusion Zones are as follows:
(i) 500 m Exclusion Zone for North Atlantic right whales;
(ii) 200 m Exclusion Zone for fin whales, sei whales, and sperm
whales; and
(iii) 25 m Exclusion Zone for harbor porpoises.
(d) Watch Zone--PSOs shall monitor a marine mammal Watch Zone that
shall encompass an area 500 m from the survey equipment. PSOs shall
document and record the behavior of all marine mammals observed within
the Watch Zone.
(e) Shutdown requirements--If a marine mammal is observed within,
entering, or approaching the relevant Exclusion Zones as described
under 4(c) while geophysical survey equipment is operational, the
geophysical survey equipment must be immediately shut down.
(i) Any PSO on duty has the authority to call for shutdown of
survey equipment. When there is certainty regarding the need for
mitigation action, the relevant PSO(s) must call for such action
immediately.
(ii) When a shutdown is called for by a PSO, the shutdown must
occur and any dispute resolved only following shutdown.
[[Page 19734]]
(iii) Upon implementation of a shutdown, survey equipment may be
reactivated when all marine mammals have been confirmed by visual
observation to have exited the relevant Exclusion Zone or an additional
time period has elapsed with no further sighting of the animal that
triggered the shutdown (15 minutes for harbor porpoise and 30 minutes
for North Atlantic right whales, fin whales, sei whales, and sperm
whales).
(iv) If geophysical equipment shuts down for reasons other than
mitigation (i.e., mechanical or electronic failure) resulting in the
cessation of the survey equipment for a period of less than 20 minutes,
the equipment may be restarted as soon as practicable if visual surveys
were continued diligently throughout the silent period and the relevant
Exclusion Zones are confirmed by PSOs to have remained clear of marine
mammals during the entire 20-minute period. If visual surveys were not
continued diligently during the pause of 20 minutes or less, a 30-
minute pre-clearance period shall precede the restart of the
geophysical survey equipment as described in 4(f). If the period of
shutdown for reasons other than mitigation is greater than 20 minutes,
a pre-clearance period shall precede the restart of the geophysical
survey equipment as described in 4(f).
(v) If a species for which authorization has not been granted, or,
a species for which authorization has been granted but the authorized
number of takes have been met, approaches or is observed within 450 m
of the survey equipment, shutdown must occur.
(f) Pre-clearance observation--30 minutes of pre-clearance
observation shall be conducted prior to initiation of geophysical
survey equipment. Geophysical survey equipment shall not be initiated
if marine mammals are observed within 200 m of the survey equipment
(500 m for North Atlantic right whales) during the pre-clearance
period. If a marine mammal is observed within 200 m of geophysical
survey equipment (500 m for North Atlantic right whales) during the
pre-clearance period, initiation of the survey equipment will be
delayed until the marine mammal(s) departs the 200 m zone (500 m for
North Atlantic right whales).
(g) Ramp-up--when technically feasible, survey equipment shall be
ramped up at the start or re-start of survey activities. Ramp-up will
begin with the power of the smallest acoustic equipment at its lowest
practical power output appropriate for the survey. When technically
feasible the power will then be gradually turned up and other acoustic
sources added in way such that the source level would increase
gradually.
(h) Vessel Strike Avoidance--Vessel operator and crew must maintain
a vigilant watch for all marine mammals and slow down or stop the
vessel or alter course, as appropriate, to avoid striking any marine
mammal, unless such action represents a human safety concern. Survey
vessel crew members responsible for navigation duties shall receive
site-specific training on marine mammal sighting/reporting and vessel
strike avoidance measures. Vessel strike avoidance measures shall
include the following, except under circumstances when complying with
these requirements would put the safety of the vessel or crew at risk:
(i) The vessel operator and crew shall maintain vigilant watch for
cetaceans and pinnipeds, and slow down or stop the vessel to avoid
striking marine mammals;
(ii) The vessel operator shall reduce vessel speed to 10 knots
(18.5 km/hr) or less when any large whale, any mother/calf pairs, whale
or dolphin pods, or larger assemblages of non-delphinoid cetaceans are
observed near (within 100 m (330 ft)) an underway vessel;
(iii) The survey vessel shall maintain a separation distance of 500
m (1,640 ft) or greater from any sighted North Atlantic right whale;
(iv) If underway, the vessel must steer a course away from any
sighted North Atlantic right whale at 10 knots (18.5 km/hr) or less
until the 500 m (1,640 ft) minimum separation distance has been
established. If a North Atlantic right whale is sighted in a vessel's
path, or within 100 m (330 ft) to an underway vessel, the underway
vessel must reduce speed and shift the engine to neutral. Engines will
not be engaged until the North Atlantic right whale has moved outside
of the vessel's path and beyond 100 m. If stationary, the vessel must
not engage engines until the North Atlantic right whale has moved
beyond 100 m;
(v) The vessel shall maintain a separation distance of 100 m (330
ft) or greater from any sighted non-delphinoid cetacean. If sighted,
the vessel underway must reduce speed and shift the engine to neutral
and must not engage the engines until the non-delphinoid cetacean has
moved outside of the vessel's path and beyond 100 m. If a survey vessel
is stationary, the vessel will not engage engines until the non-
delphinoid cetacean has moved out of the vessel's path and beyond 100
m;
(vi) The vessel shall maintain a separation distance of 50 m (164
ft) or greater from any sighted delphinoid cetacean. Any vessel
underway remain parallel to a sighted delphinoid cetacean's course
whenever possible and avoid excessive speed or abrupt changes in
direction. Any vessel underway reduces vessel speed to 10 knots (18.5
km/hr) or less when pods (including mother/calf pairs) or large
assemblages of delphinoid cetaceans are observed. Vessels may not
adjust course and speed until the delphinoid cetaceans have moved
beyond 50 m and/or the abeam of the underway vessel;
(vii) All vessels shall maintain a separation distance of 50 m (164
ft) or greater from any sighted pinniped; and
(viii) All vessels underway shall not divert or alter course in
order to approach any whale, delphinoid cetacean, or pinniped. Any
vessel underway will avoid excessive speed or abrupt changes in
direction to avoid injury to the sighted cetacean or pinniped.
(ix) The vessel operator shall comply with 10 knot (18.5 km/hr) or
less speed restrictions in any Seasonal Management Area per NMFS
guidance.
(x) If NMFS should establish a Dynamic Management Area (DMA) in the
area of the survey, within 24 hours of the establishment of the DMA,
DWW shall contact the NMFS Office of Protected Resources to determine
whether survey location and/or activities should be altered to avoid
North Atlantic right whales.
5. Monitoring Requirements--The Holder of this Authorization is
required to conduct marine mammal visual monitoring and passive
acoustic monitoring (PAM) during geophysical survey activity.
Monitoring shall be conducted in accordance with the following
requirements:
(a) A minimum of four NMFS-approved PSOs and a minimum of two
certified (PAM) operator(s), operating in shifts, shall be employed by
DWW during geophysical surveys.
(b) Observations shall take place from the highest available
vantage point on the survey vessel. General 360-degree scanning shall
occur during the monitoring periods, and target scanning by PSOs will
occur when alerted of a marine mammal presence.
(c) PSOs shall be equipped with binoculars and have the ability to
estimate distances to marine mammals located in proximity to the vessel
and/or Exclusion Zones using range finders. Reticulated binoculars will
also be available to PSOs for use as appropriate based on conditions
and visibility to support the sighting and monitoring of marine
species.
(d) PAM shall be used during nighttime geophysical survey
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operations. The PAM system shall consist of an array of hydrophones
with both broadband (sampling mid-range frequencies of 2 kHz to 200
kHz) and at least one low-frequency hydrophone (sampling range
frequencies of 75 Hz to 30 kHz). PAM operators shall communicate
detections or vocalizations to the Lead PSO on duty who shall ensure
the implementation of the appropriate mitigation measure.
(e) During night surveys, night-vision equipment with infrared
light-emitting diode spotlights and/or infrared video monitoring shall
be used in addition to PAM. Specifications for night-vision equipment
shall be provided to NMFS for review and acceptance prior to start of
surveys.
(f) PSOs and PAM operators shall work in shifts such that no one
monitor will work more than 4 consecutive hours without a 2 hour break
or longer than 12 hours during any 24-hour period. During daylight
hours the PSOs shall rotate in shifts of 1 on and 3 off, and while
during nighttime operations PSOs shall work in pairs.
(g) PAM operators shall also be on call as necessary during daytime
operations should visual observations become impaired.
(h) Position data shall be recorded using hand-held or vessel
global positioning system (GPS) units for each sighting.
(i) A briefing shall be conducted between survey supervisors and
crews, PSOs, and DWW to establish responsibilities of each party,
define chains of command, discuss communication procedures, provide an
overview of monitoring purposes, and review operational procedures.
(j) DWW shall provide resumes of all proposed PSOs and PAM
operators (including alternates) to NMFS for review and approval at
least 45 days prior to the start of survey operations.
(k) PSO Qualifications shall include completion of a PSO training
course and documented field experience on a marine mammal observation
vessel and/or aerial surveys.
(a) Data on all PAM/PSO observations shall be recorded based on
standard PSO collection requirements. PSOs must use standardized data
forms, whether hard copy or electronic. The following information shall
be reported:
(i) PSO names and affiliations.
(ii) Dates of departures and returns to port with port name.
(iii) Dates and times (Greenwich Mean Time) of survey effort and
times corresponding with PSO effort.
(iv) Vessel location (latitude/longitude) when survey effort begins
and ends; vessel location at beginning and end of visual PSO duty
shifts.
(v) Vessel heading and speed at beginning and end of visual PSO
duty shifts and upon any line change.
(vi) Environmental conditions while on visual survey (at beginning
and end of PSO shift and whenever conditions change significantly),
including wind speed and direction, Beaufort sea state, Beaufort wind
force, swell height, weather conditions, cloud cover, sun glare, and
overall visibility to the horizon.
(vii) Factors that may be contributing to impaired observations
during each PSO shift change or as needed as environmental conditions
change (e.g., vessel traffic, equipment malfunctions).
(viii) Survey activity information, such as acoustic source power
output while in operation, number and volume of airguns operating in
the array, tow depth of the array, and any other notes of significance
(i.e., pre-ramp-up survey, ramp-up, shutdown, testing, shooting, ramp-
up completion, end of operations, streamers, etc.).
(ix) If a marine mammal is sighted, the following information
should be recorded:
(A) Watch status (sighting made by PSO on/off effort,
opportunistic, crew, alternate vessel/platform);
(B) PSO who sighted the animal;
(C) Time of sighting;
(D) Vessel location at time of sighting;
(E) Water depth;
(F) Direction of vessel's travel (compass direction);
(G) Direction of animal's travel relative to the vessel;
(H) Pace of the animal;
(I) Estimated distance to the animal and its heading relative to
vessel at initial sighting;
(J) Identification of the animal (e.g., genus/species, lowest
possible taxonomic level, or unidentified); also note the composition
of the group if there is a mix of species;
(K) Estimated number of animals (high/low/best);
(L) Estimated number of animals by cohort (adults, yearlings,
juveniles, calves, group composition, etc.);
(M) Description (as many distinguishing features as possible of
each individual seen, including length, shape, color, pattern, scars or
markings, shape and size of dorsal fin, shape of head, and blow
characteristics);
(N) Detailed behavior observations (e.g., number of blows, number
of surfaces, breaching, spyhopping, diving, feeding, traveling; as
explicit and detailed as possible; note any observed changes in
behavior);
(O) Animal's closest point of approach and/or closest distance from
the center point of the acoustic source;
(P) Platform activity at time of sighting (e.g., deploying,
recovering, testing, data acquisition, other); and
(Q) Description of any actions implemented in response to the
sighting (e.g., delays, shutdown, ramp-up, speed or course alteration,
etc.) and time and location of the action.
6. Reporting--a technical report shall be provided to NMFS within
90 days after completion of survey activities that fully documents the
methods and monitoring protocols, summarizes the data recorded during
monitoring, estimates the number of marine mammals that may have been
taken during survey activities, describes the effectiveness of the
various mitigation techniques (i.e. visual observations during day and
night compared to PAM detections/operations) and provides an
interpretation of the results and effectiveness of all monitoring
tasks. Any recommendations made by NMFS shall be addressed in the final
report prior to acceptance by NMFS.
(a) Reporting injured or dead marine mammals:
(i) In the event that the specified activity clearly causes the
take of a marine mammal in a manner not prohibited by this IHA (if
issued), such as serious injury or mortality, DWW shall immediately
cease the specified activities and immediately report the incident to
the NMFS Office of Protected Resources and the NMFS Greater Atlantic
Stranding Coordinator. The report must include the following
information:
(A) Time, date, and location (latitude/longitude) of the incident;
(B) Vessel's speed during and leading up to the incident;
(C) Description of the incident;
(D) Status of all sound source use in the 24 hours preceding the
incident;
(E) Water depth;
(F) Environmental conditions (e.g., wind speed and direction,
Beaufort sea state, cloud cover, and visibility);
(G) Description of all marine mammal observations in the 24 hours
preceding the incident;
(H) Species identification or description of the animal(s)
involved;
(I) Fate of the animal(s); and
(J) Photographs or video footage of the animal(s).
Activities shall not resume until NMFS is able to review the
circumstances of the prohibited take. NMFS will work with DWW to
determine what measures are necessary to minimize the likelihood of
further prohibited take and ensure MMPA
[[Page 19736]]
compliance. DWW may not resume their activities until notified by NMFS.
(ii) In the event that DWW 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 (e.g., in less than
a moderate state of decomposition), DWW shall immediately report the
incident to the NMFS Office of Protected Resources and the NMFS Greater
Atlantic Stranding Coordinator. The report must include the same
information identified in condition 6(b)(i) of this IHA. Activities may
continue while NMFS reviews the circumstances of the incident. NMFS
will work with DWW to determine whether additional mitigation measures
or modifications to the activities are appropriate.
(iii) In the event that DWW 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 specified activities (e.g.,
previously wounded animal, carcass with moderate to advanced
decomposition, or scavenger damage), DWW shall report the incident to
the NMFS Office of Protected Resources and the NMFS Greater Atlantic
Stranding Coordinator within 24 hours of the discovery. DWW shall
provide photographs or video footage or other documentation of the
sighting to NMFS.
7. This Authorization may be modified, suspended or withdrawn if
the holder fails to abide by the conditions prescribed herein, or if
NMFS determines the authorized taking is having more than a negligible
impact on the species or stock of affected marine mammals.
Request for Public Comments
We request comment on our analyses, the draft authorization, and
any other aspect of this Notice of Proposed IHA for the proposed marine
site characterization surveys. Please include with your comments any
supporting data or literature citations to help inform our final
decision on the request for MMPA authorization.
On a case-by-case basis, NMFS may issue a one-year renewal IHA
without additional notice when (1) another year of identical or nearly
identical activities as described in the Specified Activities section
is planned, or (2) the activities would not be completed by the time
the IHA expires and renewal would allow completion of the activities
beyond that described in the Dates and Duration section, provided all
of the following conditions are met:
A request for renewal is received no later than 60 days
prior to expiration of the current IHA.
The request for renewal must include the following:
(1) An explanation that the activities to be conducted beyond the
initial dates either are identical to the previously analyzed
activities or include changes so minor (e.g., reduction in pile size)
that the changes do not affect the previous analyses, take estimates,
or mitigation and monitoring requirements.
(2) A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
Upon review of the request for renewal, the status of the
affected species or stocks, and any other pertinent information, NMFS
determines that there are no more than minor changes in the activities,
the mitigation and monitoring measures remain the same and appropriate,
and the original findings remain valid.
Dated: April 30, 2018.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2018-09481 Filed 5-3-18; 8:45 am]
BILLING CODE 3510-22-P