[Federal Register Volume 85, Number 154 (Monday, August 10, 2020)]
[Notices]
[Pages 48179-48203]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-17354]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XA303]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Marine Site Characterization
Surveys
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments on proposed authorization and possible renewal.
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SUMMARY: NMFS has received a request from [Oslash]rsted Wind Power
North America, LLC, ([Oslash]rsted) for authorization to take marine
mammals incidental to high-resolution geophysical (HRG) survey
activities in coastal waters from New York to Massachusetts in certain
areas of the Commercial Lease of Submerged Lands for Renewable Energy
Development on the Outer Continental Shelf (OCS). These areas are
currently being leased by the Applicant's affiliates, Deepwater Wind
New England, LLC, and Bay State Wind, LLC, respectively, and are
identified as OCS-A 0486/0517, OCS-A 0487, and OCS-A 0500 (collectively
referred to herein as the Lease Area). [Oslash]rsted is also planning
to conduct marine site characterization surveys along one or more
potential submarine export cable routes (ECRs) originating from the
Lease Area and landing along the shore at locations from New York to
Massachusetts, between Raritan Bay (part of the New York Bight) to
Falmouth, Massachusetts. 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, by
Level B harassment only, small numbers of marine mammals during the
specified activities. NMFS is also requesting comments on a possible
one-time one-year renewal that could be issued under certain
circumstances and, if all requirements are met, as described in Request
for Public Comments at the end of this notice. 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
September 9, 2020.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service. 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: Carter Esch, Office of Protected
Resources, NMFS, (301) 427-8421. 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
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. 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 incidental take authorization may be provided to the public
for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of such species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the mitigation,
monitoring and reporting of such takings are set forth.
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 evaluate our proposed action (i.e., the promulgation of
regulations and subsequent issuance of incidental take authorization)
and alternatives with respect to potential impacts on the human
environment.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 of the Companion Manual for NAO 216-6A,
which do not individually or cumulatively have the potential for
significant impacts on the quality of the human environment and for
which we have not identified any extraordinary circumstances that would
preclude this categorical exclusion. Accordingly, NMFS has
preliminarily determined that the proposed action qualifies to be
categorically excluded from further NEPA review.
Information in [Oslash]rsted's application and this notice
collectively provide the environmental information related to proposed
issuance of the IHA for public review and comment. We will review all
comments submitted in response to this notice prior to concluding our
NEPA process or making a final decision on the request for incidental
take authorization.
Summary of Request
On April 15, 2020, NMFS received a request from [Oslash]rsted for
authorization to take marine mammals incidental to HRG surveys in the
OCS-A 0486/0517, OCS-A 0487, and OCS-A 0500 Lease Areas designated and
offered by the Bureau of
[[Page 48180]]
Ocean Energy Management (BOEM) as well as along one or more ECRs (ECR
Area) between the southern portions of the Lease Areas and shoreline
locations from New York to Massachusetts, to support the development of
an offshore wind project. The application was considered adequate and
complete on July 1, 2020. [Oslash]rsted's request is for take, by Level
B harassment only, of small numbers of 15 species or stocks of marine
mammals. Neither [Oslash]rsted 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.
NMFS previously issued an IHA to [Oslash]rsted for similar
activities (84 FR 52464, October 2, 2019); [Oslash]rsted has complied
with all the requirements (e.g., mitigation, monitoring, and reporting)
of that IHA.
Description of the Proposed Activity
Overview
[Oslash]rsted proposes to conduct HRG surveys in support of
offshore wind development projects in the Lease Areas and ECR Area. The
purpose of the HRG surveys is to obtain a baseline assessment of
seabed/sub-surface soil conditions in the Lease Areas and ECR Area to
support the siting of potential future offshore wind projects.
Underwater sound resulting from [Oslash]rsted'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
HRG surveys, under this IHA, are anticipated to commence in
September 2020. [Oslash]rsted is proposing to conduct continuous HRG
survey operations 12-hours per day (daylight only in shallow, nearshore
locations) and 24-hours per day (offshore) using multiple vessels.
[Oslash]rsted defines a survey day as a 24-hour activity day and
assumes a vessel covers 70 kilometers (km) of survey tracks per
activity day. A survey day might be the sum of 12-hour daylight only or
multiple partial 24-hour operations (if less than 70 km is surveyed in
24 hours). Based on the planned 24-hours operations, the survey
activities for all survey segments would require 1,302 vessel days if
one vessel were surveying the entire survey line continuously. However,
an estimated 5 vessels may be used simultaneously, with a maximum of no
more than 9 vessels. Therefore, all the survey effort will be completed
in one year. See Table 1 for the estimated number of vessel days for
each survey segment. The estimated durations to complete survey
activities do not include weather downtime.
Table 1--Summary of Proposed HRG Survey Segments
------------------------------------------------------------------------
Maximum number
of survey days
using medium
Area Total number penetration
of survey days SBPs (sparkers
or boomers)
\1\
------------------------------------------------------------------------
OCS-A-0486 and OCS-A-0517............... 217 114
OCA-A-0487.............................. 261 97
OCS-A-0500.............................. 164 112
ECR Area................................ 661 378
-------------------------------
Total............................... 1,302 701
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\1\ Days with no sparkers operating will use the Innomar parametric sub-
bottom profiling equipment, ultra-short baseline positioning device
(USBL) and/or other non-impulsive acoustic sources (see Detailed
Description of Specified Activities section below).
Specific Geographic Region
[Oslash]rsted's survey activities would occur in the Lease Area
(including OCS-A 0486/0517, OCS-A 0487, and OCS-A 0500), located
approximately 14 miles (mi) south of Martha's Vineyard, Massachusetts
at its closest point, as well as within potential export cable route
corridors off the coast of New York, Connecticut, Rhode Island, and
Massachusetts (shown in Figure 1 of the IHA application). In January
2020, Deepwater Wind New England, LLC requested that BOEM assign a
portion of Lease Area OCS-A 0486 to Deepwater Wind South Fork,
designated OCS-A 0517; the Lease split was approved in April 2020.
Water depth in the Lease Area is 25-62 meters (m) and ranges from 1-90
m along potential ECRs to shoreline locations between New York and
Massachusetts.
Detailed Description of the Specified Activities
The HRG survey activities would be supported by vessels of
sufficient size to accomplish the survey goals in each of the specified
survey areas. Surveys within the ECR Area will include 24-hour and 12-
hour (daylight only) surveys. Up to nine (24-hour plus 12-hour) vessels
may work concurrently throughout the Survey Area considered in this
proposal; however, no more than 3 vessels are expected to work
concurrently within any single lease area, with an estimated four
offshore (24-hour) vessels and two nearshore (12-hour) vessels expected
to work concurrently in the ECR Area. Seasonal vessel restrictions are
detailed in the Proposed Mitigation section below. HRG equipment will
either be deployed from remotely operated vehicles (ROVs) or mounted to
or towed behind the survey vessel at a typical survey speed of
approximately 4.0 kn (7.4 km) per hour. The geophysical survey
activities proposed by [Oslash]rsted would include the following:
Shallow Penetration Sub-bottom Profilers (SBPs; CHIRPs) to
map the near-surface stratigraphy (top 0 to 5 m (0 to 16 ft) of
sediment below seabed). A CHIRP system emits sonar pulses that increase
in frequency over time. The pulse length frequency range can be
adjusted to meet project variables. These are typically mounted on the
hull of the vessel or from a side pole.
Medium penetration SBPs (Boomers) to map deeper subsurface
stratigraphy as needed. A boomer is a broad-band sound source operating
in the 3.5 Hz to 10 kHz frequency range. This system is typically
mounted on a sled and towed behind the vessel.
Medium penetration SBPs (Sparkers) to map deeper
subsurface stratigraphy as needed. A sparker
[[Page 48181]]
creates acoustic pulses from 50 Hz to 4 kHz omni-directionally from the
source that can penetrate several hundred meters into the seafloor.
These are typically towed behind the vessel with adjacent hydrophone
arrays to receive the return signals.
Parametric SBPs, also called sediment echosounders, for
providing high density data in sub-bottom profiles that are typically
required for cable routes, very shallow water, and archaeological
surveys. These are typically mounted on the hull of the vessel or from
a side pole.
Ultra-short Baseline (USBL) Positioning and Global
Acoustic Positioning System (GAPS) to provide high accuracy ranges to
track the positions of other HRG equipment by measuring the time
between the acoustic pulses transmitted by the vessel transceiver and
the equipment transponder necessary to produce the acoustic profile. It
is a two-component system with a hull or pole mounted transceiver and
one to several transponders either on the seabed or on the equipment.
Multibeam echosounder (MBES) to determine water depths and
general bottom topography. MBES sonar systems project 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.
Seafloor imaging (sidescan sonar) for seabed sediment
classification purposes, to identify natural and man-made acoustic
targets resting on the bottom as well as any anomalous features. 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. They are
typically towed beside or behind the vessel or from an autonomous
vehicle.
Table 2 identifies all the representative survey equipment that
operate below 180 kHz that may be used in support of planned
geophysical survey activities, some of which have the potential to be
detected by marine mammals. The make and model of the listed
geophysical equipment may 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, thereby reducing the duration of total survey activities.
Selection of equipment combinations is based on specific survey
objectives.
The operational frequencies for MBES and Sidescan Sonar that would
be used for these surveys are greater than 180 kHz, outside the general
hearing range of marine mammals likely to occur in the Survey Area.
These equipment types are, therefore, not considered further in this
notice.
Sparker and boomer systems, which produce the largest estimated
Level B harassment isopleths (see Estimated Take section, Table 5),
would be used for only a portion of the surveys days within the Survey
Area. Surveys days that do not utilize sparkers or boomers would use
Innomar parametric sonar systems combined with a USBL system or other
intermittent non-impulsive sources, which produce smaller estimated
Level B harassment zones (Table 5). A conservative estimate of the
number of days using sparkers or boomers is provided in Table 1.
Table 2--Summary of Representative HRG Survey Equipment
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Operating Pulse
HRG equipment category Specific HRG frequency Source level Source level Beamwidth (degrees) Typical pulse repetition
equipment range(kHz) (dB rms) (dB 0-peak) duration (ms) rate
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Shallow Sub-bottom Profilers... ET 216 (2000DS or 2-16; 2-8 195 - 24.................. 20 6
3200 top unit).
ET 424........... 4-24 176 - 71.................. 3.4 2
ET 512........... 0.7-12 179 - 80.................. 9 8
GeoPulse 5430A... 2-17 196 - 55.................. 50 10
TB Chirp III--TTV 2-7 197 - 100................. 60 15
170.
Parametric Sub-bottom Profilers Innomar, 85-115 222 - 4................... 1 40
SES[dash]2000
compact.
Innomar, 85-115 222 - 4................... 1 50
SES[dash]2000
Light & Light
Plus.
Innomar, 60-80 231 - 3................... 5 40
SES[dash]2000
Medium-70.
Innomar, 85-115 232 - 2................... 3.5 40
SES[dash]2000
Medium-100.
Innomar, 85-115 220 - 3-5................. 1 60
SES[dash]2000
Quattro.
Innomar, 90-110 220 - 5................... 0.5 40
SES[dash]2000
Smart.
Innomar, 85-115 225 - 1-3.5............... 1.5 60
SES[dash]2000
Standard &
Standard Plus.
Medium Sub-bottom Profilers.... AA, Dura-spark 0.3-1.2 203 211 Omni................ 1.1 4
UHD (400 tips,
500 J) \1\.
[[Page 48182]]
AA, Dura-spark 0.3-1.2 203 211 Omni................ 1.1 4
UHD (400+400)
\1\.
GeoMarine, Geo- 0.4-5 203 211 Omni................ 1.1 2
Source or
similar dual 400
tip sparker
(<=800 J) \1\.
GeoMarine Geo- 0.3-1.2 203 211 Omni................ 1.1 4
Source 200 tip
light weight
sparker (400 J)
\1\.
GeoMarine Geo- 0.3-1.2 203 211 Omni................ 1.1 4
Source 200-400
tip freshwater
sparker (400 J)
\1\.
AA, triple plate 0.1-5 205 211 80.................. 0.6 4
S[dash]Boom (700-
1,000 J) \2\.
Acoustic Cores................. PanGeo (LF CHIRP) 2-6.5 177.5 - 73.................. 4.5 0.06
PanGeo (HF CHIRP) 4.5-12.5 177.5 - 73.................. 4.5 0.06
Acoustic Positioning System Advances 30 NR 176 Up to 300........... 90 5
(USBL). Navigation,
Subsonus.
AA, Easytrak 18-24 189 192 Up to 180........... 10 0.125-1
Alpha.
AA, Easytrak 18-24 192 193 150-180............. 10 2
Nexus 2.
AA, Easytrak 18-24 190 192 180................. 10 2
Nexus Lite.
ET, BATS II...... 16-21 NR NR 90.................. 1-15 0.05-1.67
EvoLogics, S2C... 18-78 NR NR 100-omni............ NR NR
iXblue, IxSea 8-16 188 - Omni................ 10 1
GAPS Beacon
System.
Kongsberg HiPAP 20.5-29.6 NR 207 15.................. 30 0.8-30
501/502.
Sonardyne Ranger 19-34 194 NR NR.................. 5 1
2 and Mini
Ranger 2 USBL
HPT 3000/5/7000.
Sonardyne Scout 35-50 188 NR 5................... 5 3
Pro.
Tritech, MicroNav 20-28 NR 169 NR.................. NR 0.1-2
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- = not applicable; NR = not reported; [micro]Pa = micropascal; AA = Applied Acoustics; BATS = Broadband Acoustic Tracking System; dB = decibel; ET =
EdgeTech; GAPS = Global Acoustic Positioning System; HF = high-frequency; HiPAP = high-precision acoustic positioning system; J = joule; LF = low-
frequency; Omni = omnidirectional source; re = referenced to; SL = source level; SL0-pk = zero to peak source level; SLrms = root-mean-square source
level; UHD = ultra-high definition. For discussion of acoustic terminology, please see Potential Effects of Specified Activities on Marine Mammals and
their Habitat and Estimated Take sections.
\1\ The Dura-spark measurements and specifications provided in Crocker and Fratantonio (2016) were used for all sparker systems proposed for the survey.
The data provided in Crocker and Fratantonio (2016) represent the most applicable data for similar sparker systems with comparable operating methods
and settings when manufacturer or other reliable measurements are not available.
\2\ Crocker and Fratantonio (2016) provide S-Boom measurements using two different power sources (CSP-D700 and CSP-N). The CSP-D700 power source was
used in the 700 J measurements but not in the 1,000 J measurements. The CSP-N source was measured for both 700 J and 1,000 J operations but resulted
in a lower SL; therefore, the single maximum SL value was used for both operational levels of the S-Boom.
The deployment of certain types of HRG survey equipment, including
some of the equipment planned for use during [Oslash]rsted's proposed
activity, produces sound in the marine environment that has the
potential to result in harassment of marine mammals. Proposed
mitigation, monitoring, and reporting measures are described in 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 the 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 (SARs;
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more
[[Page 48183]]
general information about these species (e.g., physical and behavioral
descriptions) may be found on NMFS' website (www.fisheries.noaa.gov/find-species).
All species that could potentially occur in the proposed survey
areas are included in Table 6 of the IHA application. However, the
temporal and/or spatial occurrence of several species listed in Table 6
of the IHA application is such that take of these species is not
expected to occur, either because they have very low densities in the
Survey Area or are known to occur further offshore than the Survey
Area. These are: the blue whale (Balaenoptera musculus), Cuvier's
beaked whale (Ziphius cavirostris), four species of Mesoplodont beaked
whale (Mesoplodon spp.), dwarf and pygmy sperm whale (Kogia sima and
Kogia breviceps), short-finned pilot whale (Globicephala
macrorhynchus), northern bottlenose whale (Hyperoodon ampullatus),
killer whale (Orcinus orca), pygmy killer whale (Feresa attenuata),
false killer whale (Pseudorca crassidens), melon-headed whale
(Peponocephala electra), striped dolphin (Stenella coeruleoalba),
white-beaked dolphin (Lagenorhynchus albirostris), pantropical spotted
dolphin (Stenella attenuata), Fraser's dolphin (Lagenodelphis hosei),
rough-toothed dolphin (Steno bredanensis), Clymene dolphin (Stenella
clymene), spinner dolphin (Stenella longirostris), hooded seal
(Cystophora cristata), and harp seal (Pagophilus groenlandicus). As
take of these species is not anticipated as a result of the proposed
activities, these species are not analyzed further. In addition, the
Florida manatee (Trichechus manatus) may be found in the coastal waters
of the survey area. However, Florida manatees are managed by the U.S.
Fish and Wildlife Service and are not considered further in this
document.
Table 3 lists all species or stocks for which take is expected and
proposed to be authorized for this action, 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 (2020). 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 proposed for authorization, PBR and serious injury or
mortality from anthropogenic sources are 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' Atlantic SARs (e.g., Hayes et al., 2020). All values presented in
Table 3 are the most recent available at the time of publication and
are available online at: www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region.
Table 3--Marine Mammals Known To Occur in the Survey Area That May Be Affected by [Oslash]rsted's Proposed Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
ESA/MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR \3\ Annual M/
\1\ abundance survey) \2\ SI \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenidae:
North Atlantic right whale...... Eubalaena glacialis.... Western North Atlantic. E/D; Y 428 (0; 418; n/a)..... 0.8 6.85
Family Balaenopteridae (rorquals):
Humpback whale.................. Megaptera novaeangliae. Gulf of Maine.......... -/-; N 1,396 (0; 1,380; See 22 12.15
SAR).
Fin whale....................... Balaenoptera physalus.. Western North Atlantic. E/D; Y 7,418 (0.25; 6,029; 12 2.35
See SAR).
Sei whale....................... Balaenoptera borealis.. Nova Scotia............ E/D; Y 6,292 (1.015; 3,098; 6.2 1
see SAR).
Minke whale..................... Balaenoptera Canadian East Coast.... -/-; N 24,202 (0.3; 18,902; 189 8.2
acutorostrata. See SAR).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Physeteridae:
Sperm whale..................... Physeter macrocephalus. NA..................... E; Y 4,349 (0.28; 3,451; 3.9 0
See SAR).
Family Delphinidae:
Long-finned pilot whale......... Globicephala melas..... Western North Atlantic. -/-; Y 39,215 (0.30; 30,627). 306 21
Bottlenose dolphin.............. Tursiops truncatus..... Western North Atlantic -/-; N 62,851 (0.23; 51,914; 519 28
Offshore. See SAR).
Common dolphin.................. Delphinus delphis...... Western North Atlantic. -/-; N 172,825 (0.21; 1,452 419
145,216; See SAR).
Atlantic white-sided dolphin.... Lagenorhynchus acutus.. Western North Atlantic. -/-; N 93,233 (0.71; 54,443; 544 26
See SAR).
Atlantic spotted dolphin........ Stenella frontalis..... Western North Atlantic. -/-; N 39,921 (0.27; 32,032; 320 0
2012).
Risso's dolphin................. Grampus griseus........ Western North Atlantic. -/-; N 35,493 (0.19; 30,289; 303 54.3
See SAR).
Family Phocoenidae (porpoises):
Harbor porpoise................. Phocoena phocoena...... Gulf of Maine/Bay of -/-; N 95,543 (0.31; 74,034; 851 217
Fundy. See SAR).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals):
[[Page 48184]]
Gray seal \4\....................... Halichoerus grypus..... Western North Atlantic. -/-; N 27,131 (0.19; 23,158, 1,389 5,410
2016).
Harbor seal......................... Phoca vitulina......... Western North Atlantic. -/-; N 75,834 (0.15; 66,884, 2,006 350
2018).
--------------------------------------------------------------------------------------------------------------------------------------------------------
1--Endangered Species Act (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 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.
2--NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region/. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable.
3--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). Annual M/SI, found in NMFS' SARs,
represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial fisheries, subsistence hunting, ship
strike). Annual M/SI values often cannot be determined precisely and is in some cases presented as a minimum value. All M/SI values are as presented
in the 2020 SARs (Hayes et al., 2020).
4--NMFS stock abundance estimate applies to U.S. population only, actual stock abundance is approximately 505,000.
As indicated below, 15 species (with 15 managed stocks) temporally
and spatially co-occur with the survey activities to the degree that
take is reasonably likely to occur, and we have proposed authorizing
it. The following subsections provide additional information on the
biology, habitat use, abundance, distribution, and the existing threats
to the non-ESA-listed and ESA-listed marine mammals that are both
common in the waters of the outer continental shelf (OCS) of Southern
New England, and have the likelihood of occurring, at least seasonally,
in the Survey Area. These species include the North Atlantic right,
humpback, fin, sei, minke, sperm, and long-finned pilot whale,
bottlenose, common, Atlantic white-sided, Atlantic spotted, and Risso's
dolphins, harbor porpoise, and gray and harbor seals. Although the
potential for interactions with long-finned pilot whales and Atlantic
spotted and Risso's dolphins is minimal, small numbers of these species
may transit the Survey Area and are included in this analysis.
Cetaceans
North Atlantic Right Whale
The North Atlantic right whale ranges from calving grounds in the
southeastern United States to feeding grounds in New England waters and
into Canadian waters (Waring et al., 2017). Right whales have been
observed in or near southern New England during all four seasons;
however, they are most common in the spring when they are migrating
north and in the fall during their southbound migration (Kenney and
Vigness-Raposa 2009). Surveys have demonstrated the existence of seven
areas where North Atlantic right whales congregate seasonally: The
coastal waters of the southeastern U.S., the Great South Channel,
Jordan Basin, Georges Basin along the northeastern edge of Georges
Bank, Cape Cod and Massachusetts Bays, the Bay of Fundy, and the
Roseway Basin on the Scotian Shelf (Hayes et al., 2018). In addition,
modest late winter use of a region south of Martha's Vineyard and
Nantucket Islands was recently described (Stone et al., 2017). NOAA
Fisheries has designated two critical habitat areas for the NARW under
the ESA: The Gulf of Maine/Georges Bank region, and the southeast
calving grounds from North Carolina to Florida.
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 Georgia and 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
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). North
Atlantic right whales are expected to be present in the proposed survey
area during the proposed survey, especially summer months, with numbers
possibly lower in the fall. The proposed survey area is part of a
Biologically Important Area (BIA) for North Atlantic right whales; this
important 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. A map showing designated BIAs is
available at: https://cetsound.noaa.gov/biologically-important-area-map.
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
overlaps spatially with a section of the proposed Survey Area. The SMA
is active from November 1 through April 30 of each year.
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' SAR 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 indicated that the number of
adult females fell from 200 in 2010 to 186 in 2015, while the number of
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 along the U.S. and Canadian coast. As of
July 2020, a total of 31 confirmed dead stranded whales (21 in Canada;
10 in the United States) have been documented. This event has been
declared an Unusual Mortality Event
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(UME), with human interactions, including entanglement in fixed fishing
gear and vessel strikes, implicated in at least 16 of the mortalities
thus far. More information is available online at:
www.fisheries.noaa.gov/national/marine-life-distress/2017-2019-north-atlantic-right-whale-unusual-mortality-event.
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. 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 the North Atlantic feeding area
(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., 2017).
Kraus et al. (2016) observed humpbacks in the RI/MA & MA Wind
Energy Areas (WEAs) and surrounding areas during all seasons. Humpback
whales were observed most often during spring and summer months, with a
peak from April to June. Calves were observed 10 times and feeding was
observed 10 times during the Kraus et al. study (2016). That study also
observed one instance of courtship behavior. Although humpback whales
were rarely seen during fall and winter surveys, acoustic data indicate
that this species may be present within the MA WEA year-round, with the
highest rates of acoustic detections in the winter and spring (Kraus et
al., 2016). Other sightings of note include 46 sightings of humpback
whales in the New York-New Jersey Harbor Estuary documented between
2011-2016 (Brown et al., 2017).
Since January 2016, elevated humpback whale mortalities have
occurred along the Atlantic coast from Maine to Florida. The event has
been declared a UME. As of July 2020, partial or full necropsy
examinations have been conducted on approximately half of the 126 known
cases. Of the whales examined, about 50 percent had evidence of human
interaction, either ship strike or entanglement. While a portion of the
whales have shown evidence of pre-mortem vessel strike, this finding is
not consistent across all whales examined and 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.fisheries.noaa.gov/national/marine-life-distress/2016-2019-humpback-whale-unusual-mortality-event-along-atlantic-coast. A BIA for
humpback whales for feeding has been designated northeast of the lease
areas from March through December (LeBreque et al., 2015).
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 (Waring et al., 2016). They are typically
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).
Sei Whale
The Nova Scotia stock of sei whales can be found in deeper waters
of the continental shelf edge waters of the northeastern U.S. 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. The main threats
to this stock are interactions with fisheries and vessel collisions.
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 the survey areas, in
which spring to fall are times of relatively widespread and common
occurrence while during winter the species appears to be largely absent
(Waring et al., 2016).
Since January 2017, elevated minke whale mortalities have occurred
along the Atlantic coast from Maine through South Carolina. This event
has been declared a UME. As of July 2020, partial or full necropsy
examinations have been conducted on approximately 60 percent of the 92
known cases. Preliminary findings in several of the whales have shown
evidence of human interactions or infectious disease, but these
findings are not consistent across all the whales examined, so more
research is needed. More information is available at:
www.fisheries.noaa.gov/national/marine-life-distress/2017-2019-minke-whale-unusual-mortality-event-along-atlantic-coast.
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
[[Page 48186]]
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 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 these
areas through late autumn (Waring et al., 2016).
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 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, usually found
inside or near the 200 m isobaths (Waring et al., 2014).
Common Dolphin
The common dolphin is found world-wide in temperate to subtropical
seas. In the North Atlantic, 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).
Bottlenose Dolphin
There are two distinct bottlenose dolphin morphotypes in the
western North Atlantic: The coastal and offshore forms (Waring et al.,
2016). The migratory coastal morphotype resides in waters typically
less than 20 m deep, along the inner continental shelf (within 7.5 km
(4.6 miles) of shore), around islands, and is continuously distributed
south of Long Island, New York into the Gulf of Mexico. This migratory
coastal population is subdivided into 7 stocks based largely upon
spatial distribution (Waring et al., 2015). Of these 7 coastal stocks,
the Western North Atlantic Migratory Coastal Stock is common in the
coastal continental shelf waters off the coastal of New Jersey (Waring
et al., 2017). Generally, the offshore migratory morphotype is found
exclusively seaward of 34 km (21 miles) and in waters deeper than 34 m
(111.5 feet). This morphotype is primarily expected in waters north of
Long Island, New York (Waring et al., 2017; Hayes et al., 2017; 2018).
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 Western North Atlantic 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 and
Read 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).
Pinnipeds
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).
Since July 2018, elevated numbers of harbor seal and gray seal
mortalities have occurred across Maine, New Hampshire, and
Massachusetts. This event has been declared a UME. Additionally,
stranded seals have shown clinical signs as far south as Virginia,
although not in elevated numbers; therefore, the UME investigation now
encompasses all seal strandings from Maine to Virginia. Lastly, ice
seals (harp and hooded seals) have also started stranding with clinical
signs, again not in elevated numbers, and those two seal species have
also been added to the UME investigation. As of March 2020, a total of
3,152 reported strandings (of all species) had occurred. Full or
partial necropsy examinations have been conducted on some of the seals
and samples have been collected for testing. Based on tests conducted
thus far, the main pathogen found in the seals is phocine distemper
virus. NMFS is performing additional testing to identify any other
factors that may be involved in this UME. Information on this UME is
available online at: www.fisheries.noaa.gov/new-england-mid-atlantic/marine-life-distress/2018-2019-pinniped-unusual-mortality-event-along.
Gray Seal
There are three major populations of gray seals found in the world:
eastern Canada (western North Atlantic stock),
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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).
As described above, elevated seal mortalities, including gray
seals, have occurred from Maine to Virginia since July 2018. This event
has been declared a UME, with phocine distemper virus identified as the
main pathogen found in the seals. NMFS is performing additional testing
to identify any other factors that may be involved in this UME.
Information on this UME is available online at: www.fisheries.noaa.gov/new-england-mid-atlantic/marine-life-distress/2018-2019-pinniped-unusual-mortality-event-along.
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 (2018) 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 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
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 kHz.
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
(Kastelein et al., 2009; Reichmuth and Holt, 2013).
For more detail concerning these groups and associated frequency
ranges, please see NMFS Technical Guidance (2018) for a review of
available information. Fifteen marine mammal species (thirteen cetacean
and two pinnipeds (both phocid) species) have the reasonable potential
to co-occur with the proposed survey activities (see Table 3). Of the
cetacean species that may be present, five are classified as low-
frequency cetaceans (i.e., all mysticete species), seven 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 ([micro]Pa)'' and ``re: 1 [micro]Pa,'' respectively. Root mean
square (RMS) is the quadratic mean sound pressure over the duration of
an impulse. RMS is calculated by squaring all 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.,
[[Page 48188]]
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 depends 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
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 louder 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 sensitivities in both
terrestrial and marine mammals recover 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 animal 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., 2009a,b; 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 dBrms 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).
[[Page 48189]]
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 Survey Area during the HRG survey are unlikely to
incur TTS hearing impairment due to the characteristics of the sound
sources, which include relatively low source levels (176 to 232 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 2) 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 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 2) 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.
[[Page 48190]]
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), 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
long been equated with stress.
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., 2004). 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-frequency sounds. For example, Jansen (1998)
reported on the relationship between acoustic exposures and
physiological responses that are indicative of stress responses in
humans (e.g., 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 currently 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
[[Page 48191]]
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.
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 vocalizations (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., 2007). 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 stressor
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
[[Page 48192]]
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).
Disruptions 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 harbor seals might
be attracted to survey vessels 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 [Oslash]rsted'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 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
other 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
[[Page 48193]]
approached within 0.16-0.31 miles (0.25-0.5 km). Due to the relatively
high vessel traffic in the Survey Area it is possible that marine
mammals are habituated to noise (e.g., DP thrusters) from 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 kn). Given the slow vessel speeds
and predictable course necessary for data acquisition, ship strike is
unlikely to occur during the geophysical surveys. Marine mammals would
be able to easily avoid the survey vessel due to the slow vessel speed.
Further, [Oslash]rsted 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 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, section 3(18) of 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 only, in the form
of disruption of behavioral patterns for individual marine mammals
resulting from exposure to noise from certain HRG sources. Based on the
nature of the activity and the anticipated effectiveness of the
mitigation measures (i.e., exclusion zones and shutdown measures),
discussed in detail below in Proposed Mitigation section, Level A
harassment or and/or mortality is neither anticipated nor proposed to
be authorized. Below we describe how the take is estimated.
Generally speaking, we estimate take by considering: (1) Acoustic
thresholds recommended by NMFS for use in evaluating when 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 area, and (4) and the number
of days of activities. We note that while these basic factors can
contribute to a basic calculation to provide an initial prediction of
takes, additional information that can qualitatively inform take
estimates is also sometimes available (e.g., previous monitoring
results or average group size). Below, we describe the factors
considered here in more detail and present the proposed take estimate.
Acoustic Thresholds
NMFS recommends use of 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 for non-explosive sources--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 source (e.g., frequency, predictability,
duty cycle), the environment (e.g., bathymetry), and the receiving
animals (hearing, motivation, experience, demography, behavioral
context) and can be difficult to predict (Southall et al., 2007,
Ellison et al., 2012). Based on what the available science indicates
and the practical need to use a threshold based on a factor that is
both predictable and measurable for most activities, NMFS uses a
generalized acoustic threshold based on received level to estimate the
onset of behavioral harassment. NMFS predicts that marine mammals are
likely to be behaviorally harassed in a manner we consider Level B
harassment when exposed to underwater anthropogenic noise above
received levels of 120 dB re 1 microPascal root mean square ([mu]Pa
rms) for continuous (e.g., vibratory driving, drilling) and above 160
dB re 1 [mu]Pa (rms) for non-explosive impulsive (e.g., seismic
airguns) or intermittent sources (e.g., scientific sonar) sources.
[Oslash]rsted's proposed activity includes the use of intermittent
sources, therefore the 160 dB re 1 [mu]Pa (rms) threshold is
[[Page 48194]]
applicable. Some of the sources planned for use (i.e., sparkers and
boomers) are also impulsive.
Level A harassment for non-explosive sources--NMFS' Technical
Guidance for Assessing the Effects of Anthropogenic Sound on Marine
Mammal Hearing (Version 2.0) (NMFS, 2018) 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).
As mentioned previously, [Oslash]rsted's proposed activity includes the
use of impulsive (e.g., sparkers and boomers) and non-impulsive
intermittent (e.g., CHIRP SBPs) sources.
These thresholds are provided in Table 4 below. The references,
analysis, and methodology used in the development of the thresholds are
described in NMFS 2018 Technical Guidance, which may be accessed at:
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
Table 4--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
PTS onset acoustic thresholds * (received level)
----------------------------------------------------------------------------------------------------------------
Hearing group Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 219 dB; Cell 2: LE,LF,24h: 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5: Lpk,flat: 202 dB; Cell 6:LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 218 dB; Cell 8: LE,PW,24h: 201 dB.
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 232 dB; Cell 10: LE,OW,24h: 219 dB.
LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* 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 [micro]Pa, and cumulative sound exposure level (LE)
has a reference value of 1[micro]Pa \2\s. 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 (LE)
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.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that will feed into identifying the area ensonified above the
acoustic thresholds, which include sources levels and transmission loss
coefficient.
NMFS has developed a user-friendly methodology for determining the
rms sound pressure level (SPLrms) at the 160-dB isopleth for
the purposes of estimating the extent of Level B harassment isopleths
associated with HRG survey equipment (NMFS, 2020). This methodology
incorporates frequency and some directionality to refine estimated
ensonified zones. [Oslash]rsted used NMFS's methodology with additional
modifications to incorporate a seawater absorption formula and account
for energy emitted outside of the primary beam of the source. For
sources that operate with different beam widths, the maximum beam width
was used (see Table 2). The lowest frequency of the source was used
when calculating the absorption coefficient (Table 2).
NMFS considers the data provided by Crocker and Fratantonio (2016)
to represent the best available information on source levels associated
with HRG equipment and, therefore, recommends that source levels
provided by Crocker and Fratantonio (2016) be incorporated in the
method described above to estimate isopleth distances to the Level A
and Level B harassment thresholds. In cases when the source level for a
specific type of HRG equipment is not provided in Crocker and
Fratantonio (2016), NMFS recommends that either the source levels
provided by the manufacturer be used, or, in instances where source
levels provided by the manufacturer are unavailable or unreliable, a
proxy from Crocker and Fratantonio (2016) be used instead. Table 2
shows the HRG equipment types that may be used during the proposed
surveys and the sound levels associated with those HRG equipment types.
Results of modeling using the methodology described above indicated
that, of the HRG survey equipment planned for use by [Oslash]rsted that
has the potential to result in Level B harassment of marine mammals,
sound produced by the Applied Acoustics Dura-Spark UHD sparkers and
GeoMarine Geo-Source sparker would propagate furthest to the Level B
harassment threshold (141 m; Table 5). As described above, only a
portion of [Oslash]rsted's survey activity days will employ sparkers or
boomers; therefore, for the purposes of the exposure analysis, it was
assumed that sparkers would be the dominant acoustic source for
approximately 701 of the total 1,302 survey activity days. For the
remaining 601 survey days, the TB Chirp III (54 m; Table 5) was assumed
to be the dominant source. Thus, the distances to the isopleths
corresponding to the threshold for Level B harassment for sparkers (141
m) and the TB Chirp III (54 m) were used as the basis of the take
calculation for all marine mammals for 54% and 46% of survey activity
days, respectively.
[[Page 48195]]
Table 5--Modeled Radial Distances From HRG Survey Equipment to Isopleths Corresponding to Level A Harassment and
Level B Harassment Thresholds
----------------------------------------------------------------------------------------------------------------
Radial distance to level A harassment threshold (m) * Radial
---------------------------------------------------------------- distance to
level B
harassment
Sound source Low frequency Mid frequency High frequency Phocid threshold (m)
cetaceans cetaceans cetaceans pinnipeds ---------------
(underwater) All marine
mammals
----------------------------------------------------------------------------------------------------------------
ET 216 CHIRP.................... <1 <1 2.9 0 12
ET 424 CHIRP.................... 0 0 0 0 4
ET 512i CHIRP................... 0 0 <1 0 6
GeoPulse 5430................... <1 <1 36.5 <1 29
TB CHIRP III.................... <1 <1 16.9 <1 54
Innomar Parametric SBPs......... <1 <1 1.7 <1 4
AA Triple plate S-Boom (700/ <1 0 4.7 <1 76
1,000 J).......................
AA, Dura-spark UHD (500 J/400 <1 0 2.8 <1 141
tip)...........................
AA, Dura-spark UHD 400+400...... <1 0 2.8 <1 141
GeoMarine, Geo-Source dual 400 <1 0 2.8 <1 141
tip sparker....................
Pangeo Acoustic Corer (LF CHIRP) <1 0 <1 <1 4
Pangeo Acoustic Corer (HF CHIRP) <1 <1 <1 <1 4
USBL (all models)............... 0 0 1.7 0 50
----------------------------------------------------------------------------------------------------------------
* AA = Applied Acoustics; CHIRP = Compressed High-Intensity Radiated Pulse; ET = EdgeTech; SBP = Sub-bottom
Profiler; TB = Teledyne Benthos; UHD = Ultra-high Definition; USBL = Ultra-short Baseline. Distances to the
Level A harassment threshold based on the larger of the dual criteria (peak SPL and SELcum) are shown.
Isopleth distances to Level A harassment thresholds for all types
of HRG equipment and all marine mammal functional hearing groups were
modeled using the NMFS User Spreadsheet and NMFS Technical Guidance
(2018). The dual criteria (peak SPL and SELcum) were applied
to all HRG sources using the modeling methodology as described above,
and the isopleth distances for each functional hearing group were then
carried forward in the exposure analysis. For the GeoMarine Geo-Source
dual 400 tip sparker, Applied Acoustics Triple plate S-Boom and Dura-
Spark models, the peak SPL metric resulted in larger isopleth distances
for the high frequency hearing group; for all other HRG sources, the
SELcum metric resulted in larger isopleth distances.
Distances to the Level A harassment threshold based on the larger of
the dual criteria (peak SPL and SELcum) are shown in Table
5.
Distances to the Level A harassment threshold for Innomar were
calculated using a Matlab-based numerical model. Cumulative sound
exposure level from a moving source to an assumed stationary marine
mammal was calculated based on the safe distance method described in
Sivle et al. (2015), with modifications to include absorption loss and
beamwidth. The cumulative received level was then frequency weighted
using the NMFS (2018) frequency weighting function for each marine
mammal functional hearing group. Finally, the safe horizontal distance
(i.e., isopleth distance to the Level A harassment threshold) was
determined numerically at a point where the SELcum would not
exceed the 24-hour SELcum.
Modeled distances to isopleths corresponding to the Level A
harassment threshold are very small (<1 m) for three of the four marine
mammal functional hearing groups that may be impacted by the proposed
activities (i.e., low frequency and mid frequency cetaceans, and phocid
pinnipeds; see Table 5). Based on the extremely small Level A
harassment zones for these functional hearing groups, the potential for
species within these functional hearing groups to be taken by Level A
harassment is considered so low as to be discountable. These three
functional hearing groups encompass all but one of the marine mammal
species listed in Table 3 that may be impacted by the proposed
activities. There is one species (harbor porpoise) within the high
frequency functional hearing group that may be impacted by the proposed
activities. However, the largest modeled distance to the Level A
harassment threshold for the high frequency functional hearing group
was only 36.5 m (Table 5). As noted above, modeled distances to
isopleths corresponding to the Level A harassment threshold are also
assumed to be conservative. Level A harassment would also be more
likely to occur at close approach to the sound source or as a result of
longer duration exposure to the sound source, and mitigation measures--
including a 100 m exclusion zone for harbor porpoises--are expected to
minimize the potential for close approach or longer duration exposure
to active HRG sources. In addition, harbor porpoises are a notoriously
shy species which is known to avoid vessels. Harbor porpoise would also
be expected to avoid a sound source prior to that source reaching a
level that would result in injury (Level A harassment). Therefore, we
have determined that the potential for take by Level A harassment of
harbor porpoises is so low as to be discountable. As NMFS has
determined that the likelihood of take of any marine mammals in the
form of Level A harassment occurring as a result of the proposed
surveys is so low as to be discountable, we therefore do not propose to
authorize the take by Level A harassment of any marine mammals. For
more information about Level A harassment exposure estimation, please
see section 6.2.1 of the IHA application.
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 habitat-based density models produced by the Duke University
Marine Geospatial Ecology Laboratory (Roberts et al., 2016a,b, 2017,
2018) represent the best available information regarding marine mammal
densities in the proposed survey area. The density data presented by
Roberts et al. (2016a,b, 2017, 2018) incorporates aerial and shipboard
line-transect survey data from NMFS and other organizations and
incorporates data from 8 physiographic and 16 dynamic oceanographic and
biological covariates, and controls for
[[Page 48196]]
the influence of sea state, group size, availability bias, and
perception bias on the probability of making a sighting. These density
models were originally developed for all cetacean taxa in the U.S.
Atlantic (Roberts et al., 2016a,b). In subsequent years, certain models
have been updated based on additional data as well as certain
methodological improvements. More information is available online at
seamap.env.duke.edu/models/Duke-EC-GOM-2015/. Marine mammal density
estimates in the Survey Area (animals/km\2\) were obtained using the
most recent model results for all taxa (Roberts et al., 2016b, 2017,
2018). The updated models incorporate additional sighting data,
including sightings from the NOAA Atlantic Marine Assessment Program
for Protected Species (AMAPPS) surveys from 2010-2014 (NEFSC & SEFSC,
2011, 2012, 2014a, 2014b, 2015, 2016).
For the exposure analysis, density data from Roberts et al. (2016b,
2017, 2018) were mapped using a geographic information system (GIS).
Density grid cells that included any portion of the proposed Survey
Area were selected for all survey months. Densities for the recently
split Lease Areas OCS-A 0486 and OCS-A 0517 were combined, as the Lease
Areas occupy the same habitat and densities and, therefore, overlap.
For each of the survey areas (i.e., OCS-A 0486/0517, OCS-A 0487. OCS-A
0500, and ECR Area), the densities of each species as reported by
Roberts et al. (2016b, 2017, 2018) were averaged by month; those values
were then used to calculate a mean annual density for each species for
each segment of the Survey Area. Estimated mean monthly and annual
densities (animals per km\2\) of all marine mammal species that may be
taken by the proposed survey, for all survey areas, are shown in Tables
8, 9, 10, and 11 of the IHA application. The mean annual density values
used to estimate take numbers are shown in Table 6 below.
For bottlenose dolphin densities, Roberts et al. (2016b 2017, 2018)
does not differentiate by stock. The Western North Atlantic northern
migratory coastal stock primarily occurs in coastal waters from the
shoreline to approximately the 20 m isobath (Hayes et al., 2018). As
the Lease Area is located north of the northern extent of the range of
the Western North Atlantic Migratory Coastal Stock and within depths
exceeding 20 m, where only the offshore stock would be expected to
occur, all calculated bottlenose dolphin exposures within the Lease
Area are expected to be from the offshore stock. Similarly, Roberts et
al. (2018) produced density models for all seals but did not
differentiate by seal species. Because the seasonality and habitat use
by gray seals roughly overlaps with that of harbor seals in the survey
areas, it was assumed that the mean annual density of seals could refer
to either of the respective species and was, therefore, divided equally
between the two species.
Table 6--Mean Annual Marine Mammal Densities (Number of Animals per 100 km\2\) in the Survey Areas
----------------------------------------------------------------------------------------------------------------
OCS-A 0486/
Species 0517 OCS-A 0487 OCS-A 0500 ECR Area
----------------------------------------------------------------------------------------------------------------
North Atlantic right whale...................... 0.21 0.19 0.18 0.07
Humpback whale.................................. 0.14 0.13 0.12 0.05
Fin whale....................................... 0.21 0.26 0.27 0.15
Sei whale....................................... 0.01 0.01 0.02 0.01
Minke whale..................................... 0.05 0.06 0.07 0.04
Sperm Whale..................................... 0.01 0.01 0.01 0.01
Pilot whale..................................... 0.16 0.33 0.68 0.37
Bottlenose dolphin.............................. 1.17 0.77 0.72 3.51
Common dolphin.................................. 4.68 7.58 4.40 2.60
Atlantic white-sided dolphin.................... 1.46 2.55 3.86 1.98
Atlantic spotted dolphin........................ 0.01 0.02 0.05 0.05
Risso's dolphin................................. 0.00 0.00 0.01 0.01
Harbor porpoise................................. 3.44 4.62 5.65 3.20
Gray seal....................................... 0.73 0.70 0.65 1.59
Harbor seal..................................... 0.73 0.70 0.65 1.59
----------------------------------------------------------------------------------------------------------------
Note: All density values derived from Roberts et al. (2016b, 2017, 2018). Densities shown represent the mean
annual density values calculated.
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 Level B 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 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. The daily area is multiplied by the mean
annual density of a given marine mammal species. This value is then
multiplied by the number of proposed vessel days.
As noted previously, not all noise producing survey equipment/
sources will be operated concurrently by each survey vessel on every
vessel day. The greatest distance to the Level B harassment threshold
for impulsive sources (sparkers or boomers) is 141 m, while the
greatest distance to the Level B harassment threshold for other
intermittent sources (e.g., CHIRPs, Innomar, USBL) is 54 m. Therefore,
the distance used to estimate take by Level B harassment was 141 m for
the portion of survey days (54%) employing sparkers and boomers and 54
m for the portion of survey days (46%) when only non-impulsive sources
will be used.
[Oslash]rsted estimates that the proposed surveys will achieve a
maximum daily track line distance of 70 km per 24-hour day during the
proposed HRG survey activity days; this distance accounts for the
vessel traveling at approximately 4.0 kn, during active survey periods
only. Estimates of incidental take by Level B harassment for impulsive
and non-impulsive HRG equipment were calculated using the 141 m and 54
m Level B harassment isopleths, respectively, to determine the daily
ensonified areas for 24-hour operations
[[Page 48197]]
(impulsive 19.8 km\2\; non-impulsive 7.659 km\2\), estimated daily
vessel track of approximately 70 km, and the relevant species density,
multiplied by the number of survey days estimated for the specific
Survey Area segment (Tables 7 and 8).
For the North Atlantic right whale, NMFS proposes to establish a
500-m exclusion zone which substantially exceeds the distance to the
Level B harassment isopleth for both survey days using impulsive
sources (141 m) and survey days using non-impulsive sources (54 m).
However, [Oslash]rsted will be operating 24 hours per day for a
majority of the total of 1,302 vessel days. Even with the
implementation of mitigation measures (including visual monitoring at
night with use of night vision devices), it is reasonable to assume
that night time operations for an extended period could result in a
limited number of right whales being exposed to underwater sound
exceeding Level B harassment levels. Take has been conservatively
calculated based on the largest isopleth for both types of survey days
(i.e., using impulsive or non-impulsive sources), and is thereby likely
an overestimate because the acoustic source resulting in the largest
isopleth would not be used on 100 percent of survey days for each
category. In addition, [Oslash]rsted will implement specific mitigation
and monitoring protocols for both types of survey days (e.g., night
vision goggles with thermal clip-ons for nighttime operations,
exclusion zones, ramp-up and shutdown protocols). NMFS predicts that,
in the absence of mitigation, 24 right whales may be taken by Level B
harassment throughout the Survey Area over the 12-month project
duration. The conservative estimate of exposure at Level B harassment
levels coupled with the proposed monitoring and mitigation measures
make it likely that this prediction is an overestimate.
As described above, NMFS has determined that the likelihood of take
of any marine mammals in the form of Level A harassment occurring as a
result of the proposed surveys is so low as to be discountable;
therefore, we do not propose to authorize take of any marine mammals by
Level A harassment.
Table 7--Numbers of Potential Incidental Take by Level B Harassment of Marine Mammals in Each of the Survey Segments by Survey Type and Duration (* I =
Impulsive; NI = Non-Impulsive)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Estimated takes by Level B harassment
---------------------------------------------------------------------------------------
Survey type OCS-A 0486/0517 OCS-A 0487 OCS-A 0500 ECR Area
---------------------------------------------------------------------------------------
I * NI * I NI I NI I NI
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vessel days..................................................... 114 103 97 164 112 52 378 283
Species:
North Atlantic right whale.................................. 4.74 1.64 3.65 2.36 3.99 0.71 5.24 1.5
Humpback whale.............................................. 3.16 1.09 2.50 1.61 2.66 0.47 3.74 1.07
Fin whale................................................... 4.74 1.64 4.99 3.23 5.99 1.06 11.23 3.21
Sei whale................................................... 0.23 0.08 0.19 0.12 0.44 0.08 0.75 0.21
Minke whale................................................. 1.13 0.39 1.15 0.74 1.55 0.28 3.0 0.86
Sperm whale................................................. 0.02 0.08 0.19 0.12 0.22 0.04 0.75 0.21
Long-finned pilot whale..................................... 3.61 1.25 6.34 4.10 15.08 2.68 27.69 7.93
Bottlenose dolphin (W.N. Atlantic Offshore)................. 26.40 9.12 14.79 9.56 15.97 2.83 262.70 75.19
Common dolphin.............................................. 105.64 36.49 145.58 94.09 97.57 17.32 194.59 55.69
Atlantic white-sided dolphin................................ 32.96 11.38 48.98 31.65 85.60 15.19 148.19 42.41
Atlantic spotted dolphin.................................... 0.23 0.08 0.45 0.25 1.11 0.20 3.74 1.07
Risso's dolphin............................................. 0.00 0.00 0.00 0.00 0.22 0.04 0.75 0.21
Harbor porpoise............................................. 77.65 26.82 88.73 57.35 125.29 22.24 239.50 68.54
Gray seal................................................... 16.48 5.69 13.44 8.69 14.41 2.56 119.00 34.06
Harbor seal................................................. 16.48 5.69 13.44 8.69 14.41 2.56 119.00 34.06
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 8--Numbers of Potential Incidental Take of Marine Mammals Proposed for Authorization and Proposed Takes as
a Percentage of Population
----------------------------------------------------------------------------------------------------------------
Total
Estimated Proposed proposed
takes by takes by Total takes instances of
Species Level B Level B proposed for take as a
harassment harassment authorization percentage of
population
----------------------------------------------------------------------------------------------------------------
North Atlantic right whale...................... 24 24 24 5.60
Humpback whale \1\.............................. 16 21 21 1.50
Fin whale....................................... 36 36 36 0.49
Sei whale....................................... 2 2 2 0.03
Minke whale \1\................................. 9 13 13 0.05
Sperm whale \1\................................. 2 3 3 0.07
Long-finned pilot whale......................... 69 69 69 0.18
Bottlenose dolphin (W.N. Atlantic Offshore) \2\. 417 417 419 0.67
Common dolphin 1 2.............................. 747 2,205 2,211 1.28
Atlantic white-sided dolphin \2\................ 416 416 418 0.45
Atlantic spotted dolphin........................ 7 7 7 0.02
Risso's dolphin \1\............................. 1 30 30 0.08
Harbor porpoise \2\............................. 706 706 916 0.96
Harbor seal \2\................................. 214 214 215 0.28
[[Page 48198]]
Gray seal \2\................................... 214 214 215 0.79
----------------------------------------------------------------------------------------------------------------
\1\ The proposed number of authorized takes (Level B harassment only) for these species has been increased from
the estimated take number to mean group size (Risso's dolphin: Palka (2012); sperm whale: Barkaszi and Kelly
(2018)) or increased based on PSO sighting observations from [Oslash]rsted's HRG survey activities in the same
Survey Area in 2019 and 2020 (humpback and minke whales, and common dolphins).
\2\ Total take by Level B harassment proposed for authorization has been increased to include modeled exposures
resulting from estimation of take by Level A harassment, which is not anticipated (see Section 6.2.1 of the
IHA application).
Orsted has requested additional take authorizations beyond the
modelled takes for humpback and minke whales and common dolphins, based
on increased detection of these species during its 2019 survey.
Orsted's justification for this request can be found in its
application, which is available here: https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act. We specifically invite comment on this aspect of Orsted's
requested take authorization.
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 cost, impact on
operations, and, in the case of a military readiness activity,
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
Proposed Mitigation Measures
NMFS proposes the following mitigation measures be implemented
during [Oslash]rsted's proposed marine site characterization surveys.
Marine Mammal Exclusion Zones and Monitoring Zone
Marine mammal exclusion zones (EZ) would be established around the
HRG survey equipment and monitored by protected species observers
(PSOs):
500 m EZ for North Atlantic right whales;
100 m EZ for all marine mammals, with the exception of
certain small delphinids specified below, for survey days operating
impulsive acoustic sources (boomer and/or sparker).
If a marine mammal is detected approaching or entering the EZs
during the HRG survey, the vessel operator would adhere to the shutdown
procedures described below to minimize noise impacts on the animals.
These stated requirements will be included in the site-specific
training to be provided to the survey team.
Pre-Clearance of the Exclusion Zones
[Oslash]rsted would implement a 30-minute pre-clearance period of
the exclusion zones prior to the initiation of ramp-up of HRG
equipment. During this period, the exclusion zone will be monitored by
the PSOs, using the appropriate visual technology. Ramp-up may not be
initiated if any marine mammal(s) is within its respective exclusion
zone. If a marine mammal is observed within an exclusion zone during
the pre-clearance period, ramp-up may not begin until the animal(s) has
been observed exiting its respective exclusion zone or until an
additional time period has elapsed with no further sighting (i.e., 15
minutes for small odontocetes and seals, and 30 minutes for all other
species).
Ramp-Up of Survey Equipment
When technically feasible, a ramp-up procedure would be used for
HRG 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
vacate the area prior to the commencement of survey equipment operation
at full power.
A ramp-up would begin with the powering up of the smallest acoustic
HRG equipment at its lowest practical power output appropriate for the
survey. When technically feasible, the power would then be gradually
turned up and other acoustic sources would be added.
Ramp-up activities will be delayed if a marine mammal(s) enters its
respective exclusion zone. Ramp-up will continue if the animal has been
observed exiting its respective exclusion zone or until an additional
time period has elapsed with no further sighting (i.e, 15 minutes for
small odontocetes and seals and 30 minutes for all other species).
Activation of survey equipment through ramp-up procedures may not
occur when visual observation of the pre-clearance zone is not expected
to be
[[Page 48199]]
effective (i.e., during inclement conditions such as heavy rain or
fog).
Shutdown Procedures
An immediate shutdown of the impulsive HRG survey equipment would
be required if a marine mammal is sighted entering or within its
respective exclusion zone. No shutdown is required for surveys
operating only non-impulsive acoustic sources. The vessel operator must
comply immediately with any call for shutdown by the Lead PSO. Any
disagreement between the Lead PSO and vessel operator should be
discussed only after shutdown has occurred. Subsequent restart of the
survey equipment can be initiated if the animal has been observed
exiting its respective exclusion zone or until an additional time
period has elapsed (i.e., 15 minutes for small odontocetes and seals
and 30 minutes for all other species).
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
Level B harassment zone (54 m, non-impulsive; 141 m impulsive),
shutdown would occur.
If the acoustic source is shut down for reasons other then
mitigation (e.g., mechanical difficulty) for less than 30 minutes, it
may be activated again without ramp-up if PSOs have maintained constant
observation and no detections of any marine mammal have occurred within
the respective exclusion zones. If the acoustic source is shut down for
a period longer than 30 minutes and PSOs have maintained constant
observation, then pre-clearance and ramp-up procedures will be
initiated as described in the previous section.
The shutdown requirement would be waived for small delphinids of
the following genera: Delphinus, Lagenorhynchus, Stenella, and
Tursiops. Specifically, if a delphinid from the specified genera is
visually detected approaching the vessel (i.e., to bow ride) or towed
equipment, shutdown is not required. Furthermore, if there is
uncertainty regarding identification of a marine mammal species (i.e.,
whether the observed marine mammal(s) belongs to one of the delphinid
genera for which shutdown is waived), PSOs must use best professional
judgement in making the decision to call for a shutdown. Additionally,
shutdown is required if a delphinid is detected in the exclusion zone
and belongs to a genus other than those specified.
Vessel Strike Avoidance
[Oslash]rsted will ensure that vessel operators and crew maintain a
vigilant watch for cetaceans and pinnipeds and slow down or stop their
vessels to avoid striking these species. Survey vessel crew members
responsible for navigation duties will receive site-specific training
on marine mammals and sea turtle sighting/reporting and vessel strike
avoidance measures. Vessel strike avoidance measures would include the
following, except under circumstances when complying with these
requirements would put the safety of the vessel or crew at risk:
Vessel operators and crews must maintain a vigilant watch
for all protected species and slow down, stop their vessel, or alter
course, as appropriate and regardless of vessel size, to avoid striking
any protected species. A visual observer aboard the vessel must monitor
a vessel strike avoidance zone around the vessel (distances stated
below). Visual observers monitoring the vessel strike avoidance zone
may be third-party observers (i.e., PSOs) or crew members, but crew
members responsible for these duties must be provided sufficient
training to (1) distinguish protected species from other phenomena and
(2) broadly to identify a marine mammal as a right whale, other whale
(defined in this context as sperm whales or baleen whales other than
right whales), or other marine mammal.
All vessels (e.g., source vessels, chase vessels, supply
vessels), regardless of size, must observe a 10-knot speed restriction
in specific areas designated by NMFS for the protection of North
Atlantic right whales from vessel strikes: any dynamic management areas
(DMAs) when in effect, the Cape Cod Bay Seasonal Management Area (SMA)
(from January 1 through May 15), the Off Race Point SMA (from March 1
through April 30), the Great South Channel SMA (from April 1 through
July 31), the Mid-Atlantic SMAs (from November 1 through April 30), and
the Southeast SMA (from November 15 through April 15). See
www.fisheries.noaa.gov/national/endangered-species-conservation/reducing-ship-strikes-north-atlantic-right-whales for specific detail
regarding these areas.
Vessel speeds must also be reduced to 10 knots or less
when mother/calf pairs, pods, or large assemblages of cetaceans are
observed near a vessel.
All vessels must maintain a minimum separation distance of
500 m from right whales. If a whale is observed but cannot be confirmed
as a species other than a right whale, the vessel operator must assume
that it is a right whale and take appropriate action.
All vessels must maintain a minimum separation distance of
100 m from sperm whales and all other baleen whales.
All vessels must, to the maximum extent practicable,
attempt to maintain a minimum separation distance of 50 m from all
other marine mammals, with an understanding that at times this may not
be possible (e.g., for animals that approach the vessel).
When protected species are sighted while a vessel is
underway, the vessel shall take action as necessary to avoid violating
the relevant separation distance (e.g., attempt to remain parallel to
the animal's course, avoid excessive speed or abrupt changes in
direction until the animal has left the area). If marine mammals are
sighted within the relevant separation distance, the vessel must reduce
speed and shift the engine to neutral, not engaging the engines until
animals are clear of the area. This does not apply to any vessel towing
gear or any vessel that is navigationally constrained.
These requirements do not apply in any case where
compliance would create an imminent and serious threat to a person or
vessel or to the extent that a vessel is restricted in its ability to
maneuver and, because of the restriction, cannot comply.
Seasonal Operating Requirements
[Oslash]rsted will limit to three the number of survey vessels that
will operate concurrently from March through June within the Lease
Areas (OSC-A 0486/0517, OCS-A 0487, and OCS-A 500) and ECR Area north
of the Lease Areas up to, but not including, coastal and bay waters.
[Oslash]rsted would operate either a single vessel, two vessels
concurrently or, for short periods, no more than three survey vessels
concurrently in the areas described above during the March-June
timeframe when right whale densities are greatest. This practice will
help to reduce the number of right whale takes and to minimize the
number of times that right whales may be exposed to project noise in a
day.
Between watch shifts, members of the monitoring team will consult
NOAA Fisheries North Atlantic right whale reporting systems for the
presence of North Atlantic right whales throughout survey operations.
The Survey Area occurs near the SMAs located off the coast of Rhode
Island (Block Island Sounds SMA) and at the entrance to New York Harbor
(New York Bight SMA). If survey vessels transit through these SMAs,
they must adhere to the
[[Page 48200]]
seasonal mandatory speed restrictions from November 1 through April 30.
Throughout all survey operations, [Oslash]rsted will monitor NOAA
Fisheries North Atlantic right whale reporting systems for the
establishment of a DMA. If NOAA Fisheries should establish a DMA in the
Lease Area under survey, the vessels will abide by speed restrictions
in the DMA per the lease condition.
Based on our evaluation of the applicant's proposed measures, as
well as other measures considered by NMFS, NMFS has preliminarily
determined that the proposed mitigation measures provide the means of
effecting the least practicable impact on marine mammal species or
stocks and their habitat, paying particular attention to rookeries,
mating grounds, and areas of similar significance.
Proposed Monitoring and Reporting
In order to issue an 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 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).
Mitigation and monitoring effectiveness.
Proposed Monitoring Measures
Visual monitoring will be performed by qualified, NMFS-approved
PSOs, the resumes of whom will be provided to NMFS for review and
approval prior to the start of survey activities. [Oslash]rsted would
employ independent, dedicated, trained PSOs, meaning that the PSOs must
(1) be employed by a third-party observer provider, (2) have no tasks
other than to conduct observational effort, collect data, and
communicate with and instruct relevant vessel crew with regard to the
presence of marine mammals and mitigation requirements (including brief
alerts regarding maritime hazards), and (3) have successfully completed
an approved PSO training course appropriate for their designated task.
On a case-by-case basis, non-independent observers may be approved by
NMFS for limited, specific duties in support of approved, independent
PSOs on smaller vessels with limited crew capacity operating in
nearshore waters.
The PSOs will be responsible for monitoring the waters surrounding
each survey vessel to the farthest extent permitted by sighting
conditions, including exclusion zones, during all HRG survey
operations. PSOs will visually monitor and identify marine mammals,
including those approaching or entering the established exclusion zones
during survey activities. It will be the responsibility of the Lead PSO
on duty to communicate the presence of marine mammals as well as to
communicate the action(s) that are necessary to ensure mitigation and
monitoring requirements are implemented as appropriate.
During all HRG survey operations (e.g., any day on which use of an
HRG source is planned to occur), a minimum of one PSO must be on duty
during daylight operations on each survey vessel, conducting visual
observations at all times on all active survey vessels during daylight
hours (i.e., from 30 minutes prior to sunrise through 30 minutes
following sunset). Two PSOs will be on watch during nighttime
operations. The PSO(s) would ensure 360[deg] visual coverage around the
vessel from the most appropriate observation posts and would conduct
visual observations using binoculars and/or NVDs and the naked eye
while free from distractions and in a consistent, systematic, and
diligent manner. PSOs may be on watch for a maximum of four consecutive
hours followed by a break of at least two hours between watches and may
conduct a maximum of 12 hours of observation per 24-hour period. In
cases where multiple vessels are surveying concurrently, any
observations of marine mammals would be communicated to PSOs on all
nearby survey vessels.
PSOs must be equipped with binoculars and have the ability to
estimate distance and bearing to detected marine mammals, particularly
in proximity to exclusion zones. Reticulated binoculars must also be
available to PSOs for use as appropriate based on conditions and
visibility to support the sighting and monitoring of marine mammals.
During nighttime operations, night-vision goggle with thermal clip-ons
and infrared technology would be used. Position data would be recorded
using hand-held or vessel GPS units for each sighting.
During good conditions (e.g., daylight hours; Beaufort sea state
(BSS) 3 or less), to the maximum extent practicable, PSOs would also
conduct observations when the acoustic source is not operating for
comparison of sighting rates and behavior with and without use of the
active acoustic sources. Any observations of marine mammals by crew
members aboard any vessel associated with the survey would be relayed
to the PSO team.
Data on all PSO observations would be recorded based on standard
PSO collection requirements. This would include dates, times, and
locations of survey operations; dates and times of observations,
location and weather; details of marine mammal sightings (e.g.,
species, numbers, behavior); and details of any observed marine mammal
behavior that occurs (e.g., noted behavioral disturbances).
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 observed during
survey activities (by species, when known), summarizes the mitigation
actions taken during surveys (including what type of mitigation and
[[Page 48201]]
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, [Oslash]rsted will
provide the reports described below as necessary during survey
activities.
In the event that [Oslash]rsted personnel discover an injured or
dead marine mammal, [Oslash]rsted would report the incident to the NMFS
Office of Protected Resources (OPR) and the NMFS New England/Mid-
Atlantic Stranding Coordinator as soon as feasible. The report would
include the following information:
Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
Species identification (if known) or description of the
animal(s) involved;
Condition of the animal(s) (including carcass condition if
the animal is dead);
Observed behaviors of the animal(s), if alive;
If available, photographs or video footage of the
animal(s); and
General circumstances under which the animal was
discovered.
In the unanticipated event of a ship strike of a marine mammal by
any vessel involved in the activities covered by the IHA, [Oslash]rsted
would report the incident to the NMFS OPR and the NMFS New England/Mid-
Atlantic Stranding Coordinator as soon as feasible. The report would
include the following information:
Time, date, and location (latitude/longitude) of the
incident;
Species identification (if known) or description of the
animal(s) involved;
Vessel's speed during and leading up to the incident;
Vessel's course/heading and what operations were being
conducted (if applicable);
Status of all sound sources in use;
Description of avoidance measures/requirements that were
in place at the time of the strike and what additional measures were
taken, if any, to avoid strike;
Environmental conditions (e.g., wind speed and direction,
Beaufort sea state, cloud cover, visibility) immediately preceding the
strike;
Estimated size and length of animal that was struck;
Description of the behavior of the marine mammal
immediately preceding and following the strike;
If available, description of the presence and behavior of
any other marine mammals immediately preceding the strike;
Estimated fate of the animal (e.g., dead, injured but
alive, injured and moving, blood or tissue observed in the water,
status unknown, disappeared); and
To the extent practicable, photographs or video footage of
the animal(s).
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 (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of 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., 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 3, 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 from HRG surveys,
even in the absence of mitigation, and no serious injury or mortality
is proposed to be authorized. 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
was occurring), reactions that are considered to be of low severity and
with no lasting biological consequences (e.g., Southall et al., 2007).
Even repeated Level B harassment of some small subset of an overall
stock is unlikely to result in any significant realized decrease in
viability for the affected individuals, and thus would not result in
any adverse impact to the stock as a whole. As described above, Level A
harassment is not expected to occur given the nature of the operations,
the estimated size of the Level A harassment zones, the relatively low
densities of marine mammals in the Survey Area, and the required
shutdown zones for certain activities.
In addition to being temporary, the maximum expected harassment
zone around a survey vessel is 141 m; almost half of survey days would
include activity with a reduced acoustic harassment zone of 54 m per
vessel, producing expected effects of particularly low severity.
Therefore, the ensonified area surrounding each vessel is relatively
small compared to the overall distribution of the animals in the area
and their use of the habitat. Feeding behavior is not likely to be
significantly impacted as prey species are mobile and are broadly
distributed throughout the Survey 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.
ESA-listed species for which takes are proposed are North Atlantic
right, fin, sei, and sperm whales; impacts on these species are
anticipated to be limited to lower level behavioral effects. NMFS does
not anticipate that serious injury or mortality would occur to ESA-
listed species, even in the absence of proposed mitigation, and the
proposed authorization does not authorize any serious injury or
mortality. The proposed survey activities are not anticipated to affect
the fitness or reproductive success of individual animals. Since
impacts to individual survivorship and fecundity are unlikely, the
proposed survey is not expected to result in population-level effects
for any
[[Page 48202]]
ESA-listed species or alter current population trends of any ESA-listed
species.
The status of the North Atlantic right whale population is of
heightened concern and, therefore, merits additional analysis. Elevated
North Atlantic right whale mortalities began in June 2017, primarily in
Canada. Overall, preliminary findings support human interactions,
specifically vessel strikes and entanglements, as the cause of death
for the majority of right whales. The proposed survey area includes a
biologically important migratory route for North Atlantic right whales
(effective March-April and November-December) that extends from
Massachusetts to Florida (LeBrecque 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. The
spatial acoustic footprint of the proposed survey is very small
relative to the spatial extent of the available migratory habitat;
therefore, right whale migration is not expected to be impacted by the
proposed survey. Required vessel strike avoidance measures will also
decrease risk of ship strike during migration; no ship strike is
expected to occur. Additionally, only very limited take by Level B
harassment of North Atlantic right whales has been proposed as HRG
survey operations are required to maintain a 500 m EZ and shutdown if a
North Atlantic right whale is sighted at or within the EZ. The 500 m
shutdown zone for right whales is conservative, considering the Level B
harassment isopleth for the most impactful acoustic source (i.e.,
GeoMarine Geo-Source 400 tip sparker) is estimated to be 141 m, and
thereby minimizes the potential for behavioral harassment of this
species.
The proposed Survey Area includes a fin whale feeding BIA effective
between March and October. The fin whale feeding area is sufficiently
large (2,933 km\2\), and the acoustic footprint of the proposed survey
is sufficiently small that whale feeding habitat would not be reduced
in any way, and any impacts to foraging behavior within the habitat are
expected to be minimal. Behavioral harassment is typically context-
dependent, and current literature demonstrates that some mysticetes are
less likely to be susceptible to disruption of behavioral patterns when
engaged in feeding (Southall et al., 2007; Goldbogen et al., 2013;
Harris et al., 2019). Any fin whales temporarily displaced from the
proposed survey area would be expected to have sufficient 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 BIA would be expected to be
temporary in nature. Therefore, we do not expect fin whale feeding to
be negatively impacted by the proposed survey.
As noted previously, there are several active UMEs occurring in the
vicinity of [Oslash]rsted's proposed Survey Area. Elevated humpback
whale mortalities have occurred along the Atlantic coast from Maine
through Florida since January 2016. Of the cases examined,
approximately half had evidence of human interaction (ship strike or
entanglement). The UME does not yet provide cause for concern regarding
population-level impacts. Despite the UME, the relevant population of
humpback whales (the West Indies breeding population, or distinct
population segment (DPS)) remains stable at approximately 12,000
individuals.
Beginning in January 2017, elevated minke whale strandings have
occurred along the Atlantic coast from Maine through South Carolina,
with highest numbers in Massachusetts, Maine, and New York. This event
does not provide cause for concern regarding population level impacts,
as the likely population abundance is greater than 20,000 whales.
Elevated numbers of harbor seal and gray seal mortalities were
first observed in July 2018 and have occurred across Maine, New
Hampshire, and Massachusetts. Based on tests conducted so far, the main
pathogen found in the seals is phocine distemper virus, although
additional testing to identify other factors that may be involved in
this UME are underway. The UME does not yet provide cause for concern
regarding population-level impacts to any of these stocks. For harbor
seals, the population abundance is over 75,000 and annual M/SI (350) is
well below PBR (2,006) (Hayes et al., 2018). The population abundance
for gray seals in the United States is over 27,000, with an estimated
abundance, including seals in Canada, of approximately 505,000. In
addition, the abundance of gray seals is likely increasing in the U.S.
Atlantic EEZ as well as in Canada (Hayes et al., 2018).
The required mitigation measures are expected to reduce the number
and/or severity of takes by providing animals the opportunity to move
away from the sound source throughout the Survey Area before HRG survey
equipment reaches full energy, thus preventing animals from being
exposed to sound levels that have the potential to cause injury (Level
A harassment) or more severe Level B harassment. No Level A harassment
is anticipated or authorized.
NMFS expects that takes would be in the form of short-term Level B
behavioral harassment by way of brief startling reactions and/or
temporary vacating of the area, or decreased foraging (if such activity
was occurring)--reactions that (at the scale and intensity anticipated
here) are considered to be of low severity, with no lasting biological
consequences. Since both the sources and marine mammals are mobile,
animals would only be exposed briefly to a small ensonified area that
might result in take. Additionally, required mitigation measures would
further reduce exposure to sound that could result in more severe
behavioral harassment.
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 or serious injury is anticipated or
authorized;
No Level A harassment (PTS) is anticipated or authorized;
Foraging success is not likely to be significantly
impacted as effects on species that serve as prey species for marine
mammals from the survey are expected to be minimal;
The availability of alternate areas of similar habitat
value for marine mammals to temporarily vacate the survey area during
the planned survey to avoid exposure to sounds from the activity;
Take is anticipated to be primarily Level B behavioral
harassment consisting of brief startling reactions and/or temporary
avoidance of the Survey Area;
While the Survey Area is within areas noted as
biologically important for North Atlantic right whale migration, the
activities would occur in such a comparatively small area such that any
avoidance of the Survey Area due to activities would not affect
migration. In addition, mitigation measures to shutdown at 500 m to
minimize potential for Level B behavioral harassment would limit any
take of the species. Similarly, due to the small footprint of the
survey activities in relation to the size of a biologically important
area for fin whales' foraging, the survey activities would not affect
foraging behavior of this species; and
The proposed mitigation measures, including visual
monitoring and shutdowns, are expected to minimize potential impacts to
marine mammals.
[[Page 48203]]
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.
Small Numbers
As noted above, only small numbers of incidental take may be
authorized under sections 101(a)(5)(A) and (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 small relative to the
relevant stocks or populations (less than 6 percent for all species and
stocks) as shown in Table 8. 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 all 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. Within the Survey Area, fin,
sei, humpback, North Atlantic right, and sperm whales are listed as
endangered species under the ESA. Under section 7 of the ESA, BOEM
consulted with NMFS 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. NOAA's GARFO issued a Biological Opinion concluding that these
activities may adversely affect but are not likely to jeopardize the
continues existence of these marine mammal species. The Biological
Opinion can be found online at: https://www.fisheries.noaa.gov/new-england-mid-atlantic/consultations/section-7-biological-opinions-greater-atlantic-region. 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 [Oslash]rsted for HRG survey activities effective one
year from the date of issuance, provided the previously mentioned
mitigation, monitoring, and reporting requirements are incorporated. A
draft of the proposed IHA itself is available for review in conjunction
with this notice at: www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.
Request for Public Comments
We request comment on our analyses, the proposed authorization, and
any other aspect of this Notice of Proposed IHA for [Oslash]rsted's
proposed activity. We also request at this time comment on the
potential Renewal of this proposed IHA as described in the paragraph
below. Please include with your comments any supporting data or
literature citations to help inform decisions on the request for this
IHA or a subsequent Renewal IHA.
On a case-by-case basis, NMFS may issue a one-time one-year Renewal
IHA following notice to the public providing an additional 15 days for
public comments when (1) up to another year of identical or nearly
identical, or nearly identical, activities as described in the
Specified Activities section of this notice is planned or (2) the
activities as described in the Specified Activities section of this
notice would not be completed by the time the IHA expires and a Renewal
would allow for completion of the activities beyond that described in
the Dates and Duration section of this notice, provided all of the
following conditions are met:
A request for renewal is received no later than 60 days
prior to the needed Renewal IHA effective date (recognizing that the
Renewal IHA expiration date cannot extend beyond one year from
expiration of the initial IHA).
The request for renewal must include the following:
(1) An explanation that the activities to be conducted under the
requested Renewal IHA are identical to the activities analyzed under
the initial IHA, are a subset of the activities, or include changes so
minor (e.g., reduction in pile size) that the changes do not affect the
previous analyses, mitigation and monitoring requirements, or take
estimates (with the exception of reducing the type or amount of take).
(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 will remain the same and
appropriate, and the findings in the initial IHA remain valid.
Dated: August 5, 2020.
Donna Wieting,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2020-17354 Filed 8-7-20; 8:45 am]
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