[Federal Register Volume 84, Number 80 (Thursday, April 25, 2019)]
[Notices]
[Pages 17384-17405]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-08361]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XG612
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Site Characterization Surveys off
the Coast of North Carolina
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 Avangrid Renewables, LLC for
authorization to take marine mammals incidental to high-resolution
geophysical (HRG) survey investigations associated with marine site
characterization activities off the coast of North Carolina in the area
of the Commercial Lease of Submerged Lands for Renewable Energy
Development on the Outer Continental Shelf (OCS-A 0508) (the Lease
Area) and the coastal waters off North Carolina and Virginia where one
or more cable route corridors will be established. Pursuant to the
Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its
proposal to issue an incidental harassment authorization (IHA) to
incidentally take marine mammals during the specified activities. NMFS
is also requesting comments on a possible 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 May 28,
2019.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service. Physical comments should be sent to
1315 East-West Highway, Silver Spring, MD 20910 and electronic comments
should be sent to [email protected].
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments received electronically, including
all attachments, must not exceed a 25-megabyte file size. Attachments
to electronic comments will be accepted in Microsoft Word or Excel or
Adobe PDF file formats only. All comments received are a part of the
public record and will generally be posted online at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act. 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: Rob Pauline, Office of Protected
Resources, NMFS, (301) 427-8401. Electronic copies of the application
and supporting documents, as well as a list of the references cited in
this document, may be obtained online at: https://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
[[Page 17385]]
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 monitoring and
reporting of such takings must be 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 review our proposed action (i.e., the issuance of an
incidental harassment authorization) with respect to potential impacts
on the human environment.
NMFS is preparing an Environmental Assessment (EA) to consider the
environmental impacts associated with the issuance of the proposed IHA.
NMFS' EA will be made available at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.
We will review all comments submitted in response to this notice
prior to concluding our NEPA process or making a final decision on the
IHA request.
Summary of Request
On October 4, 2018, NMFS received a request from Avangrid for an
IHA to take marine mammals incidental to HRG survey investigations off
the coast of North Carolina in the OCS-A 0508 Lease Area and in the
coastal waters of Virginia and North Carolina where one or more cable
route corridors will be established to support the development of an
offshore wind project. The application was deemed adequate and complete
on February 21, 2019. Avangrid's request is for take of small numbers
of nine species by Level B harassment only. Neither Avangrid nor NMFS
expects serious injury or mortality to result from this activity and,
therefore, an IHA is appropriate.
Description of Proposed Activity
Overview
The purpose of the marine site characterization survey is to
support the siting, design, and deployment of up to three
meteorological data buoy deployment areas and obtain a baseline
assessment of seabed/sub-surface soil conditions in the Lease Area and
cable route corridors to support the siting of a proposed wind farm.
Underwater sound resulting from use of HRG equipment for site
characterization purposes can have the potential to result in
incidental take of marine mammals. The survey area extends along the
coast from near the mouth of the Chesapeake Bay to Currituck, North
Carolina. Up to 37 days of active HRG survey operations are planned and
could take place at time during the one year authorization period. This
take of marine mammals is anticipated to be in the form of harassment
only; no serious injury or mortality is anticipated, nor is any
proposed for authorization here.
Dates and Duration
HRG Surveys are anticipated to commence no earlier than June 1,
2019, and will last for approximately 37 days. This survey schedule is
based on 24-hour operations and includes estimated weather down time.
The proposed surveys are planned to take place during the summer
months. The IHA would be effective for one year.
Specific Geographic Region
Avangrid's survey activities will occur in the approximately
122,317-acre Lease Area located approximately 31.3 nautical miles off
the coast of Currituck, North Carolina, in Federal waters of the United
States (see Figure 1 in Application). In addition, multiple cable route
corridors will be surveyed within the area identified in Figure 1 in
the Application. Each survey corridor is anticipated to be 30 to 70
nautical miles and extend from the lease area to landfall locations to
be determined. For the purpose of this proposed IHA, the survey area is
considered to be the Lease Area and cable route corridors. Water depths
across the survey area are relatively shallow. Lease Area depths range
from approximately 20 to 50 m (66 to 164 feet (ft)) while the cable
route corridors will extend to shallow water close to landfall.
Detailed Description of Specific Activity
HRG surveys are employed to detect geohazards, archaeological
resources, certain types of benthic communities, and to assess seafloor
suitability for supporting structures such as platforms, pipelines,
cables, and wind turbines. These surveys for renewable energy occur in
shallow waters. HRG surveys typically use only electromechanical
sources such as side-scan sonars; boomer, sparker, and chirp sub-bottom
profilers; and multibeam depth sounders, some of which are expected to
be beyond the functional hearing range of marine mammals or would be
detectable only at very close range.\1\
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\1\ HRG surveys are distinguishable from deep penetration
seismic surveys, which occur in deeper offshore waters and are
associated with oil and gas exploration. Seismic surveys are not
used for renewable energy development. Deep penetration seismic
airgun surveys are conducted by vessels towing an array of airguns
that emit acoustic energy pulses into the seafloor, and which may
occur over long durations and over large areas. In contrast with HRG
surveys, airguns are considered a low-frequency source since most of
its acoustic energy is radiated at frequencies below 200 Hz.
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Marine site characterization surveys will include the following HRG
survey activities:
Multibeam echosounder use to determine site bathymetry and
elevations;
Seafloor imaging (sidescan sonar survey) for seabed
sediment classification purposes, to identify natural and man-made
acoustic targets resting on the bottom as well as any anomalous
features;
Shallow penetration sub-bottom profiler (pinger/chirp) to
map the near surface stratigraphy (top 0 to 5 m (0 to 16 ft) of soils
below seabed);
Medium penetration sub-bottom profiler (sparker) to map
deeper subsurface stratigraphy as needed (soils down to 75 to 100 m
(246 to 328 ft) below seabed);
Magnetic intensity measurements for detecting local
variations in regional magnetic field from geological strata and
potential ferrous objects on and below the bottom; and
Benthic Drop-down Video (DDV) and grab samples to inform
and confirm geophysical interpretations and to provide further detail
on areas of potential benthic and ecological interest.
Note that take of marine mammals is not associated with use of
magnetic intensity measurement devices, DDV, or grab sample equipment.
A technical report conducted by the Naval Undersea Warfare Center
(NUWC), through support from the Bureau of Ocean Energy Management
(BOEM) and the United States Geological Survey, published measurements
of the acoustic output from a variety of sources used during HRG
surveys (Crocker and Fratantonio,
[[Page 17386]]
2016). The HRG test equipment were operated over a wide range of
settings with different acoustic levels measured. As a conservative
measure, the highest sound source levels and pulse duration for each
piece of equipment were applied to the analysis herein. Representative
equipment and source level characteristics are listed in Table 1. The
exact make and model of the listed HRG equipment may vary depending on
availability but will be equivalent to those described here.
Table 1--Measured Source Levels of Representative HRG Survey Equipment
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Representative HRG survey Peak source RMS source Pulse duration Beam width
HRG system equipment Operating frequencies level level (ms) (degree) Signal type
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Subsea Positioning/USBL.\1\ Sonardyne Ranger 2 USBL.... 35-50 kHz 200 dBpeak 188 dBRMS 16 180 FM Chirp.
Sidescan Sonar.......................... Klein 3900 Sidescan Sonar.. 445 kHz/ 226 dBpeak 220 dBRMS 0.016 to 0.100 1 to 2 Impulse.
900 kHz
Shallow penetration sub-bottom profiler. EdgeTech 512i.............. 0.4 to 12 kHz 186 dBpeak 179 dBRMS 1.8 to 65.8 51 to 80 FM Chirp.
Parametric Shallow penetration sub- Innomar parametric SES-2000 85 to 115 kHz 243 dBpeak 236 dBRMS 0.07 to 2 1 FM Chirp.
bottom profiler. Standard.
Medium penetration sub-bottom profiler.. SIG ELC 820 Sparker........ 0.9 to 1.4 kHz 215 dBpeak 206 dBRMS 0.8 \2\ 30 Impulse.
Multibeam Echo Sounder.................. Reson T20-P................ 200/300/400 kHz 227 dBpeak 221 dBRMS 2 to 6 1.8 0.2[deg]
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1: Equipment information not provided in Crocker and Fratantonio, 2016. Information provided is based on manufacturer specifications.
2: A beamwidth of 30 degrees from horizontal is considered typical for electrode sparker technologies. Specific beamwidth information is not readily available from the equipment manufacturer.
Note that the operating frequencies of both the multibeam echo
sounder and side-scan sonar occur outside the hearing range of marine
mammals. Since there are no impacts to cetaceans associated with use of
this equipment, these sources are not considered further in this
document.
The survey activities will be supported by a vessel, or vessels,
capable of maintaining course and a survey speed of approximately 4
nautical miles per hour (knots, 7 kilometers per hour (km/hr)) while
transiting survey lines. Surveys will be conducted along tracklines
spaced 150 m (98 ft) apart, with tie-lines spaced every 500 m (1640
ft). Several survey vessels may be used simultaneously, but it is more
likely that only a single vessel would conduct surveys at any one time.
To minimize cost, the duration of survey activities, and the period
of potential impact on marine species while surveying, Avangrid has
proposed conducting continuous HRG survey operations 24 hours per day.
Based on 24-hour operations, the estimated duration of the HRG survey
activities would be approximately 37 days. Additional time (up to 30
days) may be required to obtain full multibeam coverage in shallow
water areas, however the multibeam sensor operates at frequencies above
the functional hearing ranges of marine mammals; therefore take of
marine mammals is not expected as a result of multibeam-only survey
activity, and multibeam-only survey activity is not analyzed further in
this document.
The deployment of HRG survey equipment, including the use of sound-
producing equipment operating below 200 kHz (e.g., sub-bottom
profilers), may have the potential to result in harassment of marine
mammals. Based on the frequency ranges of the potential equipment to be
used in support of the HRG survey activities; the ultra-short baseline
(USBL) positioning system and the sub-bottom profilers (shallow and
medium penetration) operate within the established marine mammal
hearing ranges and have the potential to result in Level B harassment
of marine mammals.
NMFS has previously issued IHAs for HRG surveys conducted in the
Atlantic Ocean, off the east coast of the United States. Most of these
have occurred in the coastal waters of southern New England, although
NMFS recently issued an IHA for an HRG survey investigating unexploded
ordnance (UXO) off the coast of Virginia as part of an offshore wind
project (83 FR 39062, August 8, 2018). Marine mammal monitoring reports
submitted after completion of HRG surveys indicated that authorized
take numbers have never been exceeded.
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 Activities
Sections 3 and 4 of the 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's Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species
(e.g., physical and behavioral descriptions) may be found on NMFS's
[[Page 17387]]
website (https://www.fisheries.noaa.gov/find-species).
Table 2 lists species with expected potential for take in the
survey area 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 (2018). 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's
SARs). While no mortality or serious injury is anticipated or
authorized here, PBR and annual serious injury and mortality from
anthropogenic sources are included here as gross indicators 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's stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' U.S. Atlantic SARs (e.g., Hayes et al., 2018). All values
presented in Table 2 are the most recent available at the time of
publication and are available in the 2017 SARs (Hayes et al., 2018) and
draft 2018 SARs (available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/draftmarine-mammal-stock-assessment-reports).
Table 2--Marine Mammal Species That May Occur Near the Survey Area
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Stock abundance
ESA/MMPA status; (CV, Nmin, most Annual M/SI
Common name Scientific name Stock strategic (Y/N) \1\ recent abundance PBR \3\
survey) \2\
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Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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Family Balaenidae
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North Atlantic Right whale..... Eubalaena Western North Atlantic E/D; Y 451 (0; 445; 2017) 0.9 5.56
glacialis. (WNA).
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Family Balaenopteridae (rorquals)
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Humpback whale................. Megaptera Gulf of Maine.......... -/-; N 896 (0; 896; 2012) 14.6 9.8
novaeangliae.
Fin whale...................... Balaenoptera WNA.................... E/D; Y 1,618 (0.33; 1,234; 2.5 2.5
physalus. 2011)
Sei whale...................... Balaenoptera Nova Scotia............ E/D; Y 357 (0.52; 236 0.5 0.6
borealis.
Minke whale.................... Balaenoptera Canadian East Coast.... -/-; N 2,591 (0.81; 1,425 14 7.5
acutorostrata.
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Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae
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Short-finned pilot whale....... Globicephala WNA.................... -/-; Y 21,515 (0.37; 159 192
macrorhyn-. 15,913:2011)
chus.............
Long-finned pilot whale........ Globicephala melas WNA.................... -/-; Y 5,636 (0.63; 3,464) 35 38
Bottlenose dolphin............. Tursiops spp...... WNA Offshore........... -/-; N 77,532 (0.40; 561 39.4
56053; 2016)
WNA Southern Migratory -/-; Y 3,751 (0.060; 23 0-12.3
Coastal. 2,353; 2017)
Short beaked common dolphin.... Delphinus delphis. WNA.................... -/-; N 70,184 (0.28; 557 406
55,690;2011)
Atlantic white-sided dolphin... Lagenorhynchus WNA.................... -/-; N 48,819 (0.61; 304 30
acutus. 30,403; 2011)
Atlantic spotted dolphin....... Stenella frontalis WNA.................... -/-: N 44,715 (0.43; 316 0
31,610; 2013)
Risso's dolphin................ Grampus griseus... WNA.................... -/-; N 18,250 (0.5; 126 49.7
12,619; 2011)
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Family Phocoenidae (porpoises)
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Harbor porpoise................ Phocoena phocoena. Gulf of Maine/Bay of -/-; N 79,833 (0.32; 706 255
Fundy. 61,415; 2011)
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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.
[[Page 17388]]
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--These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial
fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range.
Three marine mammal species that are listed under the Endangered
Species Act (ESA) may be present in the survey area: The North Atlantic
right whale, fin whale, and sei whale. However, NMFS is not proposing
authorized take of any of these species. The proposed authorization of
take for 10 species (with 11 managed stocks) is described in the
Estimated Take section. However, the temporal and/or spatial occurrence
of Bryde's whale, blue whale and sperm whale is such that take is not
expected to occur. While the BOEM Environmental Assessment (EA) for the
North Carolina Wind Energy Areas (2015) indicates that Bryde's whales
may be present during fall and winter, their presence in the survey
area is very rare and unlikely during the summer (BOEM 2015). The blue
whale is an occasional visitor along the northeast Atlantic coast.
Sightings of blue whales off Cape Cod, Massachusetts, in summer and
fall may represent the southern limit of the feeding range of the
western North Atlantic stock that feeds primarily off the Canadian
coast. The sperm whale occurs on the continental shelf edge, over the
continental slope, and into mid-ocean regions in deeper waters than
those in the project area. (NMFS 2015). Because the potential for the
Bryde's whale, blue whale and sperm whale to occur within the survey
area is unlikely, these species will not be described further. In
addition, while strandings data exists for harbor and gray seals along
the Mid-Atlantic coast south of New Jersey, their preference for
colder, northern waters during the survey period makes their presence
in the survey area unlikely during the summer and fall (Hayes et al
2018). Winter haulout sites for harbor seals have been identified
within the Chesapeake Bay region and Outer Banks beaches, however the
seals are only occasionally sited as far south as the Carolinas and are
not likely to be present during spring and summer months during which
survey activities are planned (Hayes et al. 2018). In addition, coastal
Virginia and North Carolina represent the southern extent of the
habitat range for gray seals, with few stranding records reported for
the even more southern waters of North Carolina and sightings occurring
only during winter months as far south as New Jersey (Waring et al.
2016). Therefore, these seal species will not be described further in
this analysis.
North Atlantic Right Whale
The North Atlantic right whale was listed as a Federal endangered
species in 1970. The right whale is a strongly migratory species, with
some portion of the population moving annually between high-latitude
feeding grounds and low latitude calving and breeding grounds. The
present range of the western North Atlantic right whale population
extends from the southeastern United States, which is utilized for
wintering and calving by some individuals, to summer feeding and
nursery grounds between New England and the Bay of Fundy and the Gulf
of St. Lawrence (Kenney 2002; Waring et al. 2011). The winter
distribution of much of the population that does not take part in
seasonal migration is largely unknown, although offshore surveys have
reported 1 to 13 detections annually in northeastern Florida and
southeastern Georgia (Waring et al. 2013). Right whales have been
observed in or near Virginia and North Carolina waters from October
through December, as well as in February and March, which coincides
with the migratory time frame for this species (Knowlton et al. 2002).
A few events of right whale calving have been documented from shallow
coastal areas and bays (Kenney 2002). Some evidence provided through
acoustic monitoring suggests that not all individuals of the population
participate in annual migrations, with a continuous presence of right
whales occupying their entire habitat range throughout the year,
particularly north of Cape Hatteras (Davis et al. 2017). However, an
analysis of the composition and distribution of individual right whale
sightings archived by the North Atlantic Right Whale Consortium from
1998 through 2015 suggests that very few whales would be present year-
round. These data also recognize changes in population distribution
throughout the right whale habitat range that could be due to
environmental or anthropogenic effects, a response to short-term
changes in the environment, or a longer-term shift in the right whale
distribution cycle (Davis et al. 2017).
The proposed survey area is part of a migratory 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. Additionally, NMFS' regulations at 50 CFR
224.105 impose vessel speed limits in designated Seasonal Management
Areas (SMA) in nearshore waters of the Mid-Atlantic Bight. SMAs were
developed to reduce the threat of collisions between ships and right
whales around their migratory route and calving grounds. NMFS requires
that all vessels 65 ft (19.8 m) or longer must travel at 10 knots or
less within the right whale SMA from November 1 through April 30 when
right whales are most likely to pass through these waters (NOAA 2010).
A small section of the cable routing area overlaps spatially with the
Chesapeake Bay SMA.
The western North Atlantic population demonstrated overall growth
of 2.8 percent per year between 1990 and 2010 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). 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. However, in 2019 at least seven right whale
calves have been identified (Savio 2019).
Elevated North Atlantic right whale mortalities have occurred since
June 7, 2017. A total of 20 confirmed dead stranded whales (12 in
Canada; 8 in the United States), have been documented to date. This
event has been declared an Unusual Mortality Event (UME), with human
interactions (i.e., fishery-related entanglements and vessel strikes)
identified as the most likely cause. More information is available
online at: https://www.fisheries.noaa.gov/national/marine-life-distress/2017-2018-north-atlantic-right-whale-unusual-mortality-event.
Humpback Whale
Humpback whales are found worldwide in all oceans. In 1973, the
[[Page 17389]]
ESA listed humpbacks as endangered. NMFS recently evaluated the status
of the species, and on September 8, 2016, NMFS divided the species into
14 distinct population segments (DPS), removed the current species-
level listing, and in its place listed four DPSs as endangered and one
DPS as threatened (81 FR 62259; September 8, 2016). The remaining nine
DPSs were not listed. The West Indies DPS, which is not listed under
the ESA, is the only DPS of humpback whale that is expected to occur in
the survey area. The best estimate of population abundance for the West
Indies DPS is 12,312 individuals, as described in the NMFS Status
Review of the Humpback Whale under the Endangered Species Act
(Bettridge et al., 2015). This abundance estimate, for the West Indies
breeding population, is more appropriate for use in reference to whales
that may occur in the survey area than is the estimate given in Table
2, which is specific to the Gulf of Maine feeding population.
Since January 2016, elevated humpback whale mortalities have
occurred along the Atlantic coast from Maine through Florida. The event
has been declared a UME. Partial or full necropsy examinations have
been conducted on approximately half of the 88 known cases. A portion
of the whales have shown evidence of pre-mortem vessel strike; however,
this finding is not consistent across all of the whales examined so
more research is needed. NOAA is consulting with researchers that are
conducting studies on the humpback whale populations, and these efforts
may provide information on changes in whale distribution and habitat
use that could provide additional insight into how these vessel
interactions occurred. More detailed information is available at:
https://www.fisheries.noaa.gov/national/marine-life-distress/2016-2018-humpback-whale-unusual-mortality-event-along-atlantic-coast#causes-of-the-humpback-whale-ume (accessed February 25, 2019). Three previous
UMEs involving humpback whales have occurred since 2000, in 2003, 2005,
and 2006.
During winter, the majority of humpback whales from North Atlantic
feeding areas 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). While migrating, humpback whales utilize
the Mid-Atlantic as a migration pathway between calving/mating grounds
to the south and feeding grounds in the north (Waring et al. 2013).
Humpbacks typically occur within the Mid-Atlantic region during fall,
winter, and spring months (Waring et al. 2012).
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., 2017). Fin whales are present north of 35-degree latitude in
every season and are broadly distributed throughout the western North
Atlantic for most of the year, though densities vary seasonally (Waring
et al., 2017). They are found in small groups of up to five individuals
(Brueggeman et al., 1987).
Present threats to fin whales are similar to other whale species,
namely fishery entanglements and vessel strikes. Fin whales seem less
likely to become entangled than other whale species. Glass et al.
(2008) reported that between 2002 and 2006, fin whales belonging to the
Gulf of Maine population were involved in only eight confirmed
entanglements with fishery equipment. Furthermore, Nelson et al. (2007)
reported that fin whales exhibited a low proportion of entanglements
(eight reported events) during their 2001 to 2005 study along the
western Atlantic. On the other hand, vessel strikes may be a more
serious threat to fin whales. Eight and 10 confirmed vessel strikes
with fin whales were reported by Glass et al. (2008) and Nelson et al.
(2007), respectively. This level of incidence was similar to that
exhibited by the other whales studied. Conversely, a study compiling
whale/vessel strike reports from historical accounts, recent whale
strandings, and anecdotal records by Laist et al. (2001) reported that
of the 11 great whale species studied, fin whales were involved in
collisions most frequently.
Fin whales are present in the Mid-Atlantic region during all four
seasons, although sightings data indicate that they are more prevalent
during winter, spring, and summer (Waring et al 2012). While fall is
the season of lowest overall abundance off Virginia and North Carolina,
they do not depart the area entirely.
Sei Whale
The sei whale is a widespread species in the world's temperate,
subpolar, subtropical, and tropical marine waters. NOAA Fisheries
considers sei whales occurring from the U.S. East Coast to Cape Breton,
Nova Scotia, and east to 42[deg] W as the ``Nova Scotia stock'' of sei
whales (Waring et al. 2016; Hayes et al. 2018). Sei whales occur in
deep water characteristic of the continental shelf edge throughout
their range (Hain et al. 1985). They are often found in pairs
(Schilling, 1992). In the Northwest Atlantic, it is speculated that the
whales migrate from south of Cape Cod along the eastern Canadian coast
in June and July, and return on a southward migration again in
September and October (Waring et al. 2014; 2016). The sei whale is most
common on Georges Bank and into the Gulf of Maine/Bay of Fundy region
during spring and summer, primarily in deeper waters.
There is limited information on the stock identity of sei whales in
the North Atlantic and insufficient data to determine trends of the
Nova Scotian sei whale population (Hayes et al. 2018). A final recovery
plan for the sei whale was published in 2011 (NOAA Fisheries 2011). Sei
whale occurrence is relatively rare in the survey area.
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., 2017). This species generally occupies waters less than
100 m deep on the continental shelf (Waring et al., 2017).
Since 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. As of September
30, 2018, partial or full necropsy examinations have been conducted on
more than 60 percent of the 57 known cases. Preliminary findings in
several of the whales have shown evidence of human interactions or
infectious disease. These findings are not consistent across all of the
whales examined, so more research is needed. As part of the UME
investigation process, NOAA is assembling an independent team of
scientists to coordinate with the Working Group on Marine Mammal
Unusual Mortality Events to review the data collected, sample stranded
whales, and determine the next steps for the investigation. More
information is available at: www.fisheries.noaa.gov/national/marine-life-distress/2017-2018-minke-whale-unusual-mortality-event-along-atlantic-coast (accessed February 25, 2019).
Pilot Whale
Both the long-finned and short-finned pilot whale could occur in
the survey
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area. However, the long-finned pilot whale is more generally found
farther north in deeper waters along the edge of the continental shelf
(a depth of 330 to 3,300 feet (100 to 1,000 meters). While long-finned
pilot whales have occasionally been observed stranded as far south as
South Carolina, long-finned and short-finned pilot whales tend to
overlap spatially along the mid-Atlantic shelf break between New Jersey
and the southern flank of Georges Bank (Payne and Heinemann 1993; Rone
and Pace 2012). The latitudinal ranges of the two species remain
uncertain, although south of Cape Hatteras, most pilot whale sightings
are expected to be short-finned pilot whales, while north of ~42[deg] N
most pilot whale sightings are expected to be long-finned pilot whales
(Hayes et al. 2018).
Bottlenose Dolphin
The bottlenose dolphin occurs in oceans and peripheral seas at both
tropical and temperate latitudes. In North America, bottlenose dolphins
are found in surface waters with temperatures ranging from 10 to
32[deg] C (50 to 90 [deg]F).
There are two distinct bottlenose dolphin morphotypes: Coastal and
offshore. The coastal morphotype resides in waters typically less than
65.6 ft (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. These coastal
populations are subdivided into seven stocks based largely upon spatial
distribution (Waring et al. 2016). Of these 7 coastal stocks, the
Western North Atlantic Southern Migratory Coastal stock is common in
the coastal continental shelf waters off the coast of Virginia and
North Carolina (Waring et al. 2018). These animals often move into or
reside in bays, estuaries, the lower reaches of rivers, and coastal
waters. The Southern Migratory Coastal Stock is one of only two (the
other being the Northern Migratory Coastal Stock) thought to make
broad-scale, seasonal migrations in coastal waters of the western North
Atlantic. The spatial distribution and migratory movements of the
Southern Migratory Coastal Stock are poorly understood and have been
defined based on movement data from satellite-tag telemetry and photo-
ID studies, and stable isotope studies. The distribution of this stock
is best described by satellite tag-telemetry data which provided
evidence for a stock of dolphins migrating seasonally along the coast
between North Carolina and northern Florida (Garrison et al. 2017b).
Tag-telemetry data collected from two dolphins tagged in November 2004
just south of Cape Fear, North Carolina, suggested that, during
October-December, this stock occupies waters of southern North Carolina
(south of Cape Lookout) where it may overlap spatially with the
Southern North Carolina Estuarine System (SNCES) Stock in coastal
waters <=3 km from shore. Based on the satellite telemetry data, during
January-March, the Southern Migratory Coastal Stock appears to move as
far south as northern Florida. During April-June, the stock moves back
north to North Carolina past the tagging site to Cape Hatteras, North
Carolina (Garrison et al. 2017b). During the warm water months of July-
August, the stock is presumed to occupy coastal waters north of Cape
Lookout, North Carolina, to Assateague, Virginia, including Chesapeake
Bay.
The Southern Migratory Coastal stock may also overlap to some
degree with the western North Atlantic Offshore stock of common
bottlenose dolphins. A combined genetic and logistic regression
analysis that incorporated depth, latitude, and distance from shore was
used to model the probability that a particular common bottlenose
dolphin group seen in coastal waters was of the coastal versus offshore
morphotype (Garrison et al. 2017a). North of Cape Hatteras during
summer months, there is strong separation between the coastal and
offshore morphotypes (Kenney 1990; Garrison et al. 2017a), and the
coastal morphotype is nearly completely absent in waters >20 m depth.
South of Cape Hatteras, the regression analysis indicated that the
coastal morphotype is most common in waters <20 m deep, but occurs at
lower densities over the continental shelf, in waters >20 m deep, where
it overlaps to some degree with the offshore morphotype. For the
purposes of defining stock boundaries, estimating abundance, and
identifying bycaught samples, the offshore boundary of the Southern
Migratory Coastal Stock is defined as the 20-m isobath north of Cape
Hatteras and the 200-m isobath south of Cape Hatteras. In summary, this
stock is best delimited in warm water months, when it overlaps least
with other stocks, as common bottlenose dolphins of the coastal
morphotype that occupy coastal waters from the shoreline to 200 m depth
from Cape Lookout to Cape Hatteras, North Carolina, and coastal waters
0-20 m in depth from Cape Hatteras to Assateague, Virginia, including
Chesapeake Bay (Hayes et al. 2018).
The biggest threat to the population is bycatch because they are
frequently caught in fishing gear, gillnets, purse seines, and shrimp
trawls (Waring et al., 2016). They have also been adversely impacted by
pollution, habitat alteration, boat collisions, human disturbance, and
are subject to bioaccumulation of toxins. Scientists have found a
strong correlation between dolphins with elevated levels of PCBs and
illness, indicating certain pollutants may weaken their immune system
(ACSonline 2004).
Common Dolphin
The short-beaked common dolphin is found world-wide in temperate to
subtropical seas. In the North Atlantic, short-beaked common dolphins
are commonly found over the continental shelf between the 100-m and
2,000-m isobaths and over prominent underwater topography and east to
the mid-Atlantic Ridge. Common dolphins have been noted to be
associated with Gulf Stream features (CETAP 1982; Selzer and Payne
1988; Waring et al., 1992). The species is less common south of Cape
Hatteras, although schools have been reported as far south as the
Georgia/South Carolina border (Hayes et al., 2018).
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., 2017). The Gulf of Maine stock is most common in continental shelf
waters from Hudson Canyon to Georges Bank, and in the Gulf of Maine and
lower Bay of Fundy. Sighting data indicate seasonal shifts in
distribution (Northridge et al., 1997). During January to May, low
numbers of white-sided dolphins are found from Georges Bank to Jeffreys
Ledge (off New Hampshire), with even lower numbers south of Georges
Bank, as documented by a few strandings collected on beaches of
Virginia to South Carolina. From June through September, large numbers
of white-sided dolphins are found from Georges Bank to the lower Bay of
Fundy. From October to December, white-sided dolphins occur at
intermediate densities from southern Georges Bank to southern Gulf of
Maine. Infrequent Virginia and North Carolina observations appear to
represent the southern extent of the species' range during the winter
months (Hayes et al., 2018).
Atlantic Spotted Dolphin
There are two species of spotted dolphin in the Atlantic Ocean, the
Atlantic spotted dolphin (Stenella frontalis) and the pantropical
spotted
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dolphin (S. attenuata) (Perrin et al., 1987).
The Atlantic spotted dolphin ranges from southern New England,
south through the Gulf of Mexico and the Caribbean to Venezuela
(Leatherwood et al., 1976; Perrin et al., 1994). The Atlantic spotted
dolphin prefers tropical to warm temperate waters along the continental
shelf 10 to 200 meters (33 to 650 feet) deep to slope waters greater
than 500 meters (1640 feet) deep. They regularly occur in continental
shelf waters south of Cape Hatteras and in continental shelf edge and
continental slope waters north of this region (Payne et al., 1984;
Mullin and Fulling 2003). Pantropical spotted dolphin sightings during
surveys in the Atlantic have been concentrated in the slope waters
north of Cape Hatteras while in waters south of Cape Hatteras sightings
are recorded over the Blake Plateau and in deeper offshore waters of
the mid-Atlantic. (NMFS 2014). Given that pantropical spotted dolphins
are found in deeper slope waters, it is likely that only Atlantic
spotted dolphins, preferring shallower waters, would be found in the
survey area.
Risso's Dolphins
Risso's dolphins are distributed worldwide in tropical and
temperate seas and in the Northwest Atlantic occur from Florida to
eastern Newfoundland. Off the northeastern U.S. coast, Risso's dolphins
are distributed along the continental shelf edge from Cape Hatteras
northward to Georges Bank during spring, summer, and autumn. In winter,
the range is in the mid-Atlantic Bight and extends outward into oceanic
waters. In general, the population occupies the mid-Atlantic
continental shelf edge year round (Hayes et al., 2018).
Harbor Porpoise
The harbor porpoise inhabits shallow, coastal waters, often found
in bays, estuaries, and harbors. In the western Atlantic, they are
found from Cape Hatteras north to Greenland. During summer (July to
September), harbor porpoises are concentrated in the northern Gulf of
Maine and southern Bay of Fundy region, generally in waters less than
150 m deep with a few sightings in the upper Bay of Fundy and on
Georges Bank. During fall (October-December) and spring (April-June),
harbor porpoises are widely dispersed from New Jersey to Maine, with
lower densities farther north and south. They are seen from the
coastline to deep waters (>1800 m) although the majority of the
population is found over the continental shelf. During winter (January
to March), intermediate densities of harbor porpoises can be found in
waters off New Jersey to North Carolina, and lower densities are found
in waters off New York to New Brunswick, Canada. There does not appear
to be a temporally coordinated migration or a specific migratory route
to and from the Bay of Fundy region. However, during the fall, several
satellite-tagged harbor porpoises did favor the waters around the 92-m
isobaths (Hayes et al., 2018)
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 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 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.
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of available information.
Twelve marine mammal species, all cetaceans, have the reasonable
potential to co-occur with the proposed survey activities. Please refer
to Table 2. Of these cetacean species, 5 are classified as low-
frequency cetaceans (i.e., all mysticete species), 6 are classified as
mid-frequency cetaceans (i.e., all delphinid species), and 1 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
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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 of the sound amplitudes, averaging the squares, and then
taking the square root of the average (Urick, 1975). RMS accounts for
both positive and negative values; squaring the pressures makes all
values positive so that they may be accounted for in the summation of
pressure levels. This measurement is often used in the context of
discussing behavioral effects, in part because behavioral effects,
which often result from auditory cues, may be better expressed through
averaged units rather than by peak pressures.
Acoustic Impacts
HRG survey equipment use during the geophysical surveys may
temporarily impact marine mammals in the area due to elevated in-water
sound levels. Marine mammals are continually exposed to many sources of
sound. Naturally occurring sounds such as lightning, rain, sub-sea
earthquakes, and biological sounds (e.g., snapping shrimp, whale songs)
are widespread throughout the world's oceans. Marine mammals produce
sounds in various contexts and use sound for various biological
functions including, but not limited to: (1) Social interactions; (2)
foraging; (3) orientation; and (4) predator detection. Interference
with producing or receiving these sounds may result in adverse impacts.
Audible distance, or received levels of sound depend on the nature of
the sound source, ambient noise conditions, and the sensitivity of the
receptor to the sound (Richardson et al., 1995). Type and significance
of marine mammal reactions to sound are likely dependent on a variety
of factors including, but not limited to, (1) the behavioral state of
the animal (e.g., feeding, traveling, etc.); (2) frequency of the
sound; (3) distance between the animal and the source; and (4) the
level of the sound relative to ambient conditions (Southall et al.,
2007).
When 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 a kilometer away. Acousticians often refer to the loudness
of a sound at its source (typically referenced to one meter from the
source) as the source level and the loudness of sound elsewhere as the
received level (i.e., typically the receiver). For example, a humpback
whale 3 km from a device that has a source level of 230 dB may only be
exposed to sound that is 160 dB loud, depending on how the sound
travels through water (e.g., spherical spreading (6 dB reduction with
doubling of distance) was used in this example) and assuming no other
sources of propagation loss (see below). 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.
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). 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 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). Given the higher level
of sound and/or longer durations of exposure necessary to cause PTS as
compared with TTS, and the small zone within which sound levels would
exceed criteria for onset of PTS, it is unlikely that PTS would occur
during the proposed HRG surveys.
Temporary Threshold Shift
TTS is the mildest form of hearing impairment that can occur during
exposure to a loud sound (Kryter, 1985). While experiencing TTS, the
hearing threshold rises and a sound must be stronger in order to be
heard. At least in terrestrial mammals, TTS can last from minutes or
hours to (in cases of strong TTS) days, can be limited to a particular
frequency range, and can occur to varying degrees (i.e., a loss of a
certain number of dBs of sensitivity). For sound exposures at or
somewhat above the TTS threshold, hearing sensitivity in both
terrestrial and marine mammals recovers rapidly after exposure to the
noise ends.
Marine mammal hearing plays a critical role in communication with
conspecifics and in interpretation of environmental cues for purposes
such as predator avoidance and prey capture. Depending on the degree
(elevation of threshold in dB), duration (i.e., recovery time), and
frequency range of TTS and the context in which it is experienced, TTS
can have effects on marine mammals ranging from discountable to
serious. For example, a marine mammal may be able to readily compensate
for a brief, relatively small amount of TTS in a non-critical frequency
range that takes place during a time when the animals is traveling
through the open ocean, where ambient noise is lower and there are not
as many competing sounds present. Alternatively, a larger amount and
longer duration of TTS sustained during a time when communication is
critical for successful mother/calf interactions could have more
serious impacts if it were in the same frequency band as the necessary
vocalizations and of a severity such 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, harbor porpoise, and Yangtze finless
porpoise) exposed to a limited number of sound sources (i.e., mostly
tones and octave-band
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noise) in laboratory settings (e.g., Finneran et al., 2002 and 2010;
Nachtigall et al., 2004; Lucke et al., 2009; Mooney et al., 2009; Popov
et al., 2011; Finneran and Schlundt, 2010). In general, harbor
porpoises (Lucke et al., 2009; Kastelein et al., 2012b) have a lower
TTS onset than other measured 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). 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 NMFS (2018), Southall et al. (2019), Finneran and Jenkins
(2012), and 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 level
(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; however, NMFS does not
consider TTS-onset to be the lowest level at which Level B harassment
may occur.
Marine mammals 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 low source levels (208 to 221 dB re 1
[micro]Pa-m) and generally very short pulses and duration of the sound.
Even for high-frequency cetacean species (e.g., harbor porpoises),
which may have increased sensitivity to TTS (Lucke et al., 2009;
Kastelein et al., 2012b), individuals would have to make a very close
approach and also remain very close to vessels operating these sources
in order to receive multiple exposures at relatively high levels, as
would be necessary to cause TTS. Intermittent exposures--as would occur
due to the brief, transient signals produced by these sources--require
a higher cumulative SEL to induce TTS than would continuous exposures
of the same duration (i.e., intermittent exposure results in lower
levels of TTS) (Mooney et al., 2009a; Finneran et al., 2010). Moreover,
most marine mammals would be more likely to 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 temporary threshold shift 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 sub-bottom profiler and other HRG survey equipment makes it
unlikely that an animal would be exposed more than briefly during the
passage of the vessel. Boebel et al. (2005) concluded similarly for
single and multibeam echosounders, and more recently, Lurton (2016)
conducted a modeling exercise and concluded similarly that likely
potential for acoustic injury from these types of systems is
discountable, but that behavioral response cannot be ruled out. Animals
may avoid the area around the survey vessels, thereby reducing
exposure. Any disturbance to marine mammals is likely to be in the form
of temporary avoidance or alteration of opportunistic foraging behavior
near the survey location.
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 (Thompson,
1965; 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
signal and the brief period when an individual mammal is likely to be
within its beam.
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Non-Auditory Physical Effects (Stress)
Classic stress responses begin when an animal's central nervous
system perceives a potential threat to its homeostasis. That perception
triggers stress responses regardless of whether a stimulus actually
threatens the animal; the mere perception of a threat is sufficient to
trigger a stress response (Moberg, 2000; Seyle, 1950). Once an animal's
central nervous system perceives a threat, it mounts a biological
response or defense that consists of a combination of the four general
biological defense responses: Behavioral responses, autonomic nervous
system responses, neuroendocrine responses, or immune responses.
In the case of many stressors, an animal's first and sometimes most
economical (in terms of biotic costs) response is behavioral avoidance
of the potential stressor or avoidance of continued exposure to a
stressor. An animal's second line of defense to stressors involves the
sympathetic part of the autonomic nervous system and the classical
``fight or flight'' response which includes the cardiovascular system,
the gastrointestinal system, the exocrine glands, and the adrenal
medulla to produce changes in heart rate, blood pressure, and
gastrointestinal activity that humans commonly associate with
``stress.'' These responses have a relatively short duration and may or
may not have significant long-term effect on an animal's welfare.
An animal's third line of defense to stressors involves its
neuroendocrine systems; the system that has received the most study has
been the hypothalamus-pituitary-adrenal system (also known as the HPA
axis in mammals or the hypothalamus-pituitary-interrenal axis in fish
and some reptiles). Unlike stress responses associated with the
autonomic nervous system, virtually all neuro-endocrine functions that
are affected by stress--including immune competence, reproduction,
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been
implicated in failed reproduction (Moberg, 1987; Rivier, 1995), altered
metabolism (Elasser et al., 2000), reduced immune competence (Blecha,
2000), and behavioral disturbance. Increases in the circulation of
glucocorticosteroids (cortisol, corticosterone, and aldosterone in
marine mammals; see Romano et al., 2004) have been equated with stress
for many years.
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and distress is the biotic cost
of the response. During a stress response, an animal uses glycogen
stores that can be quickly replenished once the stress is alleviated.
In such circumstances, the cost of the stress response would not pose a
risk to the animal's welfare. However, when an animal does not have
sufficient energy reserves to satisfy the energetic costs of a stress
response, energy resources must be diverted from other biotic function,
which impairs those functions that experience the diversion. For
example, when mounting a stress response diverts energy away from
growth in young animals, those animals may experience stunted growth.
When mounting a stress response diverts energy from a fetus, an
animal's reproductive success and its fitness will suffer. In these
cases, the animals will have entered a pre-pathological or pathological
state which is called ``distress'' (Seyle, 1950) or ``allostatic
loading'' (McEwen and Wingfield, 2003). This pathological state will
last until the animal replenishes its biotic reserves sufficient to
restore normal function. Note that these examples involved a long-term
(days or weeks) stress response exposure to stimuli.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses have also been documented
fairly well through controlled experiments; because this physiology
exists in every vertebrate that has been studied, it is not surprising
that stress responses and their costs have been documented in both
laboratory and free-living animals (for examples see, Holberton et al.,
1996; Hood et al., 1998; Jessop et al., 2003; Krausman et al., 2004;
Lankford et al., 2005; Reneerkens et al., 2002; Thompson and Hamer,
2000). Information has also been collected on the physiological
responses of marine mammals to exposure to anthropogenic sounds (Fair
and Becker, 2000; Romano et al., 2002). For example, Rolland et al.
(2012) found that noise reduction from reduced ship traffic in the Bay
of Fundy was associated with decreased stress in North Atlantic right
whales. In a conceptual model developed by the Population Consequences
of Acoustic Disturbance (PCAD) working group, serum hormones were
identified as possible indicators of behavioral effects that are
translated into altered rates of reproduction and mortality (NRC 2005).
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 (for
example, elevated respiration and increased heart rates). Jones (1998)
reported on reductions in human performance when faced with acute,
repetitive exposures to acoustic disturbance. Trimper et al. (1998)
reported on the physiological stress responses of osprey to low-level
aircraft noise while Krausman et al. (2004) reported on the auditory
and physiology stress responses of endangered Sonoran pronghorn to
military overflights. Smith et al. (2004a, 2004b), for example,
identified noise-induced physiological transient stress responses in
hearing-specialist fish (i.e., goldfish) that accompanied short- and
long-term hearing losses. Welch and Welch (1970) reported physiological
and behavioral stress responses that accompanied damage to the inner
ears of fish and several mammals.
Hearing is one of the primary senses marine mammals use to gather
information about their environment and to communicate with
conspecifics. Although empirical information on the effect of 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.
NMFS does not expect that the generally short-term, intermittent, and
transitory HRG surveys would create conditions of long-term, continuous
noise and chronic acoustic exposure
[[Page 17395]]
leading to long-term physiological stress responses in marine mammals.
Behavioral Disturbance
Behavioral responses to sound are highly variable and context-
specific. An animal's perception of and response to (in both nature and
magnitude) an acoustic event can be influenced by prior experience,
perceived proximity, bearing of the sound, familiarity of the sound,
etc. (Southall et al., 2007; DeRuiter et al., 2013a and 2013b). 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).
Southall et al. (2007) reports the results of the efforts of a
panel of experts in acoustic research from behavioral, physiological,
and physical disciplines that convened and reviewed the available
literature on marine mammal hearing and physiological and behavioral
responses to human-made sound with the goal of proposing exposure
criteria for certain effects. This peer-reviewed compilation of
literature is very valuable, though Southall et al. (2007) note that
not all data are equal, some have poor statistical power, insufficient
controls, and/or limited information on received levels, background
noise, and other potentially important contextual variables--such data
were reviewed and sometimes used for qualitative illustration but were
not included in the quantitative analysis for the criteria
recommendations. All of the studies considered, however, contain an
estimate of the received sound level when the animal exhibited the
indicated response.
Studies that address responses of low-frequency cetaceans to sounds
include data gathered in the field and related to several types of
sound sources, including: vessel noise, drilling and machinery
playback, low-frequency M-sequences (sine wave with multiple phase
reversals) playback, tactical low-frequency active sonar playback,
drill ships, and non-pulse playbacks. These studies generally indicate
no (or very limited) responses to received levels in the 90 to 120 dB
re: 1[micro]Pa range and an increasing likelihood of avoidance and
other behavioral effects in the 120 to 160 dB range. As mentioned
earlier, though, contextual variables play a very important role in the
reported responses and the severity of effects do not increase linearly
with received levels. Also, few of the laboratory or field datasets had
common conditions, behavioral contexts, or sound sources, so it is not
surprising that responses differ.
The studies that address responses of mid-frequency cetaceans to
sounds include data gathered both in the field and the laboratory and
related to several different sound sources, including: pingers,
drilling playbacks, ship and ice-breaking noise, vessel noise, acoustic
harassment devices (AHDs), acoustic deterrent devices (ADDs), mid-
frequency active sonar, and non-pulse bands and tones. Southall et al.
(2007) were unable to come to a clear conclusion regarding the results
of these studies. In some cases animals in the field showed significant
responses to received levels between 90 and 120 dB, while in other
cases these responses were not seen in the 120 to 150 dB range. The
disparity in results was likely due to contextual variation and the
differences between the results in the field and laboratory data
(animals typically responded at lower levels in the field). The studies
that address the responses of mid-frequency cetaceans to impulse sounds
include data gathered both in the field and the laboratory and related
to several different sound sources, including: small explosives, airgun
arrays, pulse sequences, and natural and artificial pulses. The data
show no clear indication of increasing probability and severity of
response with increasing received level. Behavioral responses seem to
vary depending on species and stimuli.
The studies that address responses of high-frequency cetaceans to
sounds include data gathered both in the field and the laboratory and
related to several different sound sources, including: Pingers, AHDs,
and various laboratory non-pulse sounds. All of these data were
collected from harbor porpoises.
Marine mammals are likely to avoid the HRG survey activity,
especially harbor porpoises. However, because the sub-bottom profilers
and other HRG survey equipment operate from a moving vessel, and the
assumed behavioral harassment distance is small (see Estimated Take),
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, therefore 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 Avangrid's use of HRG survey equipment, on the basis of a 2008
mass stranding of approximately one hundred 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
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,
[[Page 17396]]
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 kilometers. However, other studies have shown that
marine mammals at distances more than a few kilometers 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 and toothed whales 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). Due to the relatively high
vessel traffic in the survey area it is possible that marine mammals
are habituated to noise from project vessels in the area.
Vessel Strike
Ship strikes of marine mammals can cause major wounds, which may
lead to the death of the animal. An animal at the surface could be
struck directly by a vessel, a surfacing animal could hit the bottom of
a vessel, or a vessel's propeller could injure an animal just below the
surface. The severity of injuries typically depends on the size and
speed of the vessel (Knowlton and Kraus, 2001; Laist et al., 2001;
Vanderlaan and Taggart, 2007).
The most vulnerable marine mammals are those that spend extended
periods of time at the surface in order to restore oxygen levels within
their tissues after deep dives (e.g., the sperm whale). In addition,
some baleen whales, such as the North Atlantic right whale, seem
generally unresponsive to vessel sound, making them more susceptible to
vessel collisions (Nowacek et al., 2004). These species are primarily
large, slow moving whales. Smaller marine mammals (e.g., bottlenose
dolphin) move quickly through the water column and are often seen
riding the bow wave of large ships. Marine mammal responses to vessels
may include avoidance and changes in dive pattern (NRC, 2003).
An examination of all known ship strikes from all shipping sources
(civilian and military) indicates vessel speed is a principal factor in
whether a vessel strike results in death (Knowlton and Kraus, 2001;
Laist et al., 2001; Jensen and Silber, 2003; Vanderlaan and Taggart,
2007). In assessing records with known vessel speeds, Laist et al.
(2001) found a direct relationship between the occurrence of a whale
strike and the speed of the vessel involved in the collision. The
authors concluded that most deaths occurred when a vessel was traveling
in excess of 24.1 km/h (14.9 mph; 13 knots). 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 vessels and are likely already
habituated to the presence of numerous vessels in the area. Further,
Avangrid will implement measures (e.g., vessel speed restrictions and
separation distances; see Proposed Mitigation Measures) to reduce the
risk of a vessel strike to marine mammal species in the survey area.
Effects on Marine Mammal Habitat
There are no feeding areas, rookeries, or mating grounds known to
be biologically important to marine mammals within the proposed project
area with the exception of a migratory BIA for right whales which was
described previously. There is also no designated critical habitat for
any ESA-listed marine mammals. NMFS' regulations at 50 CFR 224.105
designated the nearshore waters of the Mid-Atlantic Bight as the Mid-
Atlantic SMA for right whales in 2008. Mandatory vessel speed
restrictions are in place in that SMA from November 1 through April 30
to reduce the threat of collisions between ships and right whales
around their migratory route and calving grounds.
We are not aware of any available literature on impacts to marine
mammal prey species from HRG survey equipment. However, because the HRG
survey equipment introduces noise to the marine environment, there is
the potential for avoidance of the area around the HRG survey
activities by marine mammal prey species. Any avoidance of the area on
the part of marine mammal prey species would be expected to be short
term and temporary. Because of the temporary nature of the disturbance,
the availability of similar habitat and resources (e.g., prey species)
in the surrounding area, and the lack of important or unique marine
mammal habitat, 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).
As described previously, no mortality is anticipated or proposed to
be authorized for this activity. Below we describe how the take is
estimated.
Generally speaking, we estimate take by considering: (1) Acoustic
thresholds above which NMFS believes the best available science
indicates marine mammals will be behaviorally harassed or incur some
degree of permanent hearing impairment; (2) the area or volume of water
that will be ensonified above these levels in a day; (3) the density or
occurrence of marine mammals within these ensonified areas; and, (4)
and the number of days of activities. We note that while these basic
factors can contribute to a calculation to provide an initial
prediction of takes, additional information that can qualitatively
inform take estimates is also sometimes available (e.g., previous
monitoring
[[Page 17397]]
results or average group size). Below, we describe the factors
considered here in more detail and present the proposed take estimate.
Acoustic Thresholds
Using the best available science, NMFS has developed 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 160 dB re 1 [mu]Pa (rms) for non-explosive impulsive
(e.g., seismic airguns) or intermittent (e.g., scientific sonar)
sources. Avangrid's proposed activity includes the use of impulsive
and/or intermittent sources (HRG equipment) and, therefore, the 160 dB
re 1 [mu]Pa (rms) is applicable.
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).
Avangrid's proposed activity includes the use of impulsive sources
(medium penetration sub-bottom profiler) and non-impulsive sources
(shallow penetration sub-bottom profiler).
These thresholds are provided in the table 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:
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
Table 3--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 (FF) 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: 201 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 [mu]Pa, and cumulative sound exposure level (LE) has
a reference value of 1[mu]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 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 source levels and transmission loss
coefficient.
Previously we explained that auditory injury of marine mammals is
unlikely given the higher level of sound and/or longer durations of
exposure necessary to cause PTS and the small zone within which sound
levels would exceed criteria for onset of PTS. The information provided
in Tables 4 and 5 support this position and demonstrate that the
proposed mitigation measures are based on a highly conservative
evaluation of potential acoustic impacts.
When the NMFS Technical Guidance was first published in 2016, in
recognition of the fact that ensonified area/volume could be more
technically challenging to predict because of the duration component in
the new thresholds, we developed a User Spreadsheet that includes tools
to help predict a simple isopleth that can be used in conjunction with
marine mammal density or occurrence to help predict takes. We note that
because of some of the assumptions included in the methods used for
these tools, we anticipate that isopleths produced are typically going
to be overestimates of some degree, which may result in some degree of
overestimate of Level A harassment take. However, these tools offer the
best way to predict appropriate isopleths when more sophisticated 3D
modeling methods are not available. NMFS continues to develop ways to
quantitatively refine these tools, and will qualitatively address the
output where appropriate. For mobile sources, including the HRG survey
equipment, the User Spreadsheet predicts the closest distance at which
a stationary animal would not incur PTS if the sound source traveled by
the animal in a straight line at a constant speed. Note however, that
use of the spreadsheet is generally not appropriate for use in
assessing potential for Level A harassment for very highly directional
sources, such as the Innomar SES-2000, for reasons explained below.
Inputs used in the User Spreadsheet and the resulting isopleths are
reported below.
[[Page 17398]]
Table 4--User Spreadsheet Input Parameters Used for Calculating Harassment Isopleths
----------------------------------------------------------------------------------------------------------------
USBL Shallow Medium
------------------- penetration SBP penetration SBP
-------------------------------------
Spreadsheet tab used D: Mobile source: D: Mobile source: F: Mobile source:
Non-impulsive, Non-impulsive, Impulsive,
intermittent intermittent intermittent
----------------------------------------------------------------------------------------------------------------
Source Level (dB)...................................... 188 RMS SPL 179 RMS SPL 206 RMS SPL
Weighting Factor Adjustment (kHz)...................... 26.5 2.6 1.4
Source Velocity (m/s).................................. 2.058 2.058 2.058
Pulse Duration (seconds)............................... 0.016 0.0658 0.008
1/Repetition rate- (seconds)........................... 0.33 0.25 0.25
Source Level (PK SPL).................................. ................. ................. 215
Propagation (xLogR).................................... 20 20 20
----------------------------------------------------------------------------------------------------------------
Note that the Innomar SES-2000 is a specialized type of HRG sub-
bottom profiler that uses the principle of ``parametric'' or
``nonlinear'' acoustics to generate short narrow-beam sound pulses. As
no field data currently exists for the Innomar sub-bottom profiler
acoustic modeling was completed using a version of the U.S. Naval
Research Laboratory's Range-dependent Acoustic Model (RAM) and BELLHOP
Gaussian beam ray-trace propagation model (Porter and Liu 1994).
Calculations of the ensonified area are conservative due to the
directionality of the sound sources. Due to the short sound pulses and
the highly directional sound pulse transmission (1[deg] beamwidth) of
parametric sub-bottom profilers, the volume of area affected is much
lower than using conventional (linear) acoustics devices such as
sparker and chirp systems. Level A harassment zones of less than 5
meters (Table 5) for HF cetaceans were calculated for this HRG
equipment in the proposed survey area while Level B harassment
isopleths were found to range from 120 to 135 meters (Table 6).
Table 5--Maximum Distances to Level A Harassment Thresholds by Equipment Category
----------------------------------------------------------------------------------------------------------------
Lateral
Representative HRG survey equipment Marine mammal group PTS onset distance (m)
----------------------------------------------------------------------------------------------------------------
USBL/GAPS Positioning Systems
----------------------------------------------------------------------------------------------------------------
Sonardyne Ranger 2 USBL HPT 5/7000...... LF cetaceans.............. 199 dB SELcum.............
MF cetaceans.............. 198 dB SELcum.............
HF cetaceans.............. 173 dB SELcum............. 3
----------------------------------------------------------------------------------------------------------------
Shallow Sub-bottom Profiler
----------------------------------------------------------------------------------------------------------------
Edgetech 512i........................... LF cetaceans.............. 199 dB SELcum.............
MF cetaceans.............. 198 dB SELcum.............
HF cetaceans.............. 173 dB SELcum.............
----------------------------------------------------------------------------------------------------------------
Shallow Parametric Sub-bottom Profiler
----------------------------------------------------------------------------------------------------------------
Innomar SES-2000 Standard Parametric Sub- LF cetaceans.............. 199 dB SELcum............. N/A
bottom Profiler.
MF cetaceans.............. 198 dB SELcum.............
HF cetaceans.............. 173 dB SELcum............. <5
----------------------------------------------------------------------------------------------------------------
Medium Penetration Sub-bottom Profiler
----------------------------------------------------------------------------------------------------------------
SIG ELC 820 Sparker..................... LF cetaceans.............. 219 dBpeak, 183 dB SELcum. --, 10
MF cetaceans.............. 230 dBpeak, 185 dB SELcum. --,--
HF cetaceans.............. 202 dBpeak, 155 dB SELcum. 5, 4
----------------------------------------------------------------------------------------------------------------
Notes:
The peak SPL criterion is un-weighted (i.e., flat weighted), whereas the cumulative SEL criterion is weighted
for the given marine mammal functional hearing group.
The calculated sound levels and results are based on NMFS Technical Guidance's companion User Spreadsheet except
as indicated.
-- indicates that no injury was predicted for the given HRG equipment noise profile.
N/A indicates not applicable as the HRG sound source operates outside the effective marine mammal hearing range
Distances to Level B harassment noise thresholds were calculated
using the conservative practical spreading model (transmission loss
(TL) equation: TL = 15log10r), with the exception of the
Innomar SES-2000 described previously. The Sig ELC 820 Sparker was
calculated to have the largest Level B harassment isopleth of 200 m
(656.2 ft). To account for some of the potential variation of operating
conditions, the maximum distance of 200 m to the harassment thresholds
is used to determine estimated exposure. The 200 m distance to the
medium penetration sub-bottom profiler represents the largest distance
and is likely a very conservative estimate based on sound
[[Page 17399]]
source field verification assessments of similar sparker electrode
equipment.
The 200 m distance to the medium penetration sub-bottom profiler
represents the largest distance and is likely a very conservative
estimate based on sound source field verification assessments of
similar sparker electrode equipment.
Table 6--Distances to Level B Harassment Thresholds
[160 dBRMS]
------------------------------------------------------------------------
Marine mammal
level B
Survey equipment harassment 160
dBRMS re 1
[micro]Pa (m)
------------------------------------------------------------------------
USBL
------------------------------------------------------------------------
Sonardyne Ranger 2 USBL.............................. 25
------------------------------------------------------------------------
Shallow penetration sub-bottom profiler
------------------------------------------------------------------------
EdgeTech 512i........................................ 10
Innomar parametric SES-2000 Standard................. 120-135
------------------------------------------------------------------------
Medium penetration sub-bottom profiler
------------------------------------------------------------------------
SIG ELC 820 Sparker.................................. 200
------------------------------------------------------------------------
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 data used as the basis for estimating cetacean
density (``D'') for the survey area are sightings per unit effort
(SPUE) derived by Duke University (Roberts et al. 2016a), updated with
new modeling results (Roberts et al. 2016b; 2017; 2018). SPUE (or, the
relative abundance of species) is derived by using a measure of survey
effort and number of individual cetaceans sighted. SPUE allows for
comparison between discrete units of time (i.e. seasons) and space
within a project area (Shoop and Kenney, 1992). The Duke University
(Roberts et al. 2016) cetacean density data represent models derived
from aggregating line-transect surveys conducted over 23 years by five
institutions (NOAA NMFS Northeast Fisheries Science Center, New Jersey
Department of Environmental Protection, NOAA NMFS Southeast Fisheries
Science Center, University of North Carolina Wilmington, and Virginia
Aquarium & Marine Science Center). Model versions discussed in Roberts
et al. (2016a) are freely available online at the Ocean Biogeographic
Information System Spatial Ecological Analysis of Megavertebrate
Populations (OBISSEAMAP) repository. Monthly mean density values within
the survey area were averaged by season (Winter (December, January,
February), Spring (March, April, May), Summer (June, July, August),
Fall (September, October, November)) to provide seasonal density
estimates for those taxa for which monthly model results are available.
The highest seasonal density estimates during the duration of the
proposed survey were used to estimate take (i.e., summer or fall).
(2016b; 2017; 2018).
Take Calculation and Estimation
Here we describe how the information provided above is brought
together to produce a quantitative take estimate. In order to estimate
the number of marine mammals predicted to be exposed to sound levels
that would result in harassment, radial distances to predicted
isopleths corresponding to harassment thresholds are calculated, as
described above. Those distances are then used to calculate the area(s)
around the HRG survey equipment predicted to be ensonified to sound
levels that exceed harassment thresholds. The area estimated to be
ensonified to relevant thresholds in a single day of the survey is then
calculated, based on areas predicted to be ensonified around the HRG
survey equipment and the estimated survey vessel trackline distance
traveled per day.
The survey activities that have the potential to cause Level B
harassment (160 dBRMS re 1 [micro]Pa) are listed in Table 6.
Based on the results of this assessment, the furthest distance to the
Level B harassment criteria is 200 m from the use of the SIG ELC 820
Sparker. As a conservative measure to account for some of the potential
variation of operating conditions, the maximum distance of 200 m to the
Level B harassment isopleth for the SIG ELC 820 Sparker is used to
determine estimated exposure for the entire HRG survey.
The estimated distance of the daily vessel trackline was determined
using the estimated average speed of the vessel (4 knots) and the 24-
hour operational period. Using the maximum distance to the Level B
harassment threshold of 200 m (656 ft) and estimated daily vessel track
of approximately 177.8 km (110.5 mi), estimates of take by survey
equipment has been based on an ensonified area around the survey
equipment of 71.2 km\2\ (27.5 mi\2\) per day over a projected survey
period for each survey segment as shown in Table 7.
Table 7--Survey Segment Distances and Level B Harassment Zones
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Calculated
Number of Estimated Estimated level B
Survey segment active survey distances per total line harassment
days day (km) distance zone per day
(km\2\)
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Lease Area...................................... 29 177.8 5,156 71.2
Cable Route Corridor............................ 8 177.8 1,422 71.2
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The parameters in Table 7 were used to estimate the potential take
by incidental harassment for each segment of the HRG survey. Density
data from Roberts et al. (2016b; 2017; 2018) were mapped within the
boundary of the survey area for each segment (Figure 1 in application)
using geographic information systems. For both survey segments, species
densities, as reported by Roberts et al. (2016) within the maximum
survey area, were averaged by season (spring and summer) based on the
proposed HRG survey schedule (commencing no earlier than June 1, 2019).
Potential take calculations were then based on the maximum average
seasonal species density (between spring and summer) within the maximum
survey area, given the survey start date and duration. Results of the
take calculations by survey segment are provided in Table 8.
[[Page 17400]]
Table 8--Marine Mammal Density and Estimated Take by Level B Harassment
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Lease area Cable Corridor Route Totals
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Maximum Maximum
average average
Species seasonal Calculated seasonal Calculated Total take Percent of
density \1\ Take (number) density \1\ Take (number) authorization population
(No. /100 km (No. /100 km (number)
\2\) \2\)
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North Atlantic right whale.............................. 0.051 1.063 0.051 0.288 3 0
Humpback whale.......................................... 0.466 9.631 0.102 0.581 10 1.11
Fin whale............................................... 0.328 6.773 0.128 0.729 3 0
Sei whale............................................... 0.020 0.406 0.003 0.018 0
Minke whale............................................. 0.757 15.643 0.171 0.9722 17 0.65
Pilot whale............................................. 0.100 2.073 0.034 0.195 4 5 10 <0.01
Harbor porpoise......................................... 1.252 25.874 0.690 3.931 30 <0.01
Bottlenose dolphin (WNA southern migratory coastal) \2\. 0.000 0.000 49.102 104.944 105 2.8
Bottlenose dolphin (offshore) \2\....................... 6.409 132.413 49.102 174.906 307 <0.01
Short beaked common dolphin............................. 5.241 108.275 2.144 12.221 120 0.17
Atlantic white-sided dolphin............................ 2.482 51.288 0.320 1.826 53 0.11
Atlantic spotted dolphin................................ 8.895 183.772 3.493 19.910 204 0.46
Risso's dolphin......................................... 0.074 1.525 0.074 0.421 \4\ 40 0.21
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\1\ Density values from Duke University (Roberts et al. 2016b; 2017; 2018).
\2\ Estimates split based on bottlenose dolphin stock preferred water depths (Reeves et al. 2002; Waring et al. 2016).
\3\ No take proposed for authorization, as discussed below.
\4\ Adjusted for group size.
\5\ For short-finned and long-finned pilot whales, percentage of stock taken is <0.01percent both species if all 10 takes are allocated separately to
each species.
Since the calculated take value for pilot whales (2) is less than
the mean group size (9.4), NMFS assumed that take of at least one group
of pilot whales could occur (Silva et al, 2014). For bottlenose dolphin
densities, Roberts et al. (2016b; 2017; 2018) does not differentiate by
individual stock. Given the southern coastal migratory stock's
propensity to be found in waters shallower than the 20 m depth isobath
north of Cape Hatteras (Reeves et al. 2002; Waring et al. 2016), the
Export Cable Corridor segment was roughly divided along the 20 m depth
isobath. The Lease Area is located within depths exceeding 20 m, where
the southern coastal migratory stock would be unlikely to occur.
Roughly 40 percent of the Export Cable Corridor is 20 m or less in
depth. Given the Export Cable Corridor area is estimated to take 8 days
to complete survey activity, 3 days have been estimated for depths
shallower than 20 m. Therefore, to account for the potential for mixed
stocks within the Export Cable Corridor, 3 days has been applied to the
take estimation equation for the southern coastal migratory stock and
the remaining applied to the offshore stock (5 days). The offshore
stock is the only stock of bottlenose dolphins that may occur in the
lease area; therefore bottlenose dolphin densities within the Lease
Area have been considered part of the offshore stock only for purposes
of take estimation.
For Risso's dolphins, NMFS adjusted the calculated take number to
account for group size. These dolphins are usually seen in groups of 12
to 40, but loose aggregations of 100 to 200 or more are seen
occasionally (Reeves et al., 2002). NMFS conservatively assumed that a
group of 40 or several smaller groups not exceeding a total of 40 takes
by Level B harassment.
The three ESA-listed large whales that could potentially be present
in the survey area occur at very low densities, and the calculated
numbers of potential acoustic exposures above the 160-dB threshold are
small, i.e., one right whale exposure, zero sei whale exposures, and
eight fin whale exposures. In addition, Avangrid proposed a 500 m
(1,640 ft) exclusion zone for the right whale and NMFS recommended a
200 m (656 ft) exclusion zone for sei and fin whales. Both of these
measures are incorporated into the proposed IHA (see ``Proposed
Mitigation''). These exclusion zones exceed (in the case of right
whales) or equal (in the case of sei and fin whales) the distance to
the conservatively calculated Level B harassment isopleth. Given the
low likelihood of exposure in context of the proposed mitigation
requirements (with relatively high detection probabilities for large
whales at these distances during good visibility), we believe that
there is not a reasonably anticipated potential for the specified
activity to cause the disruption of behavioral patterns for these
species. Therefore, we do not propose to authorize take by Level B
harassment for these species.
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
[[Page 17401]]
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.
Avangrid's application included a list of proposed mitigation
measures during site characterization surveys utilizing HRG survey
equipment. NMFS proposes the additional measure of establishing an
exclusion zone of 200 m for sei and fin whales. The mitigation measures
outlined in this section are based on protocols and procedures that
have been successfully implemented and previously approved by NMFS
(DONG Energy, 2016, ESS, 2013; Dominion, 2013 and 2014).
Visual Monitoring
Visual monitoring of designated exclusion and Level B harassment
zones will ensure that (1) Any take of ESA-listed species would be
limited; (2) exposure to underwater noise does not result in injury
(Level A harassment), and (3) the number of instances of take does not
exceed the authorized amounts. PSOs will coordinate to ensure 360[deg]
visual coverage around the vessel and conduct visual observations while
free from distractions and in a consistent, systematic, and diligent
manner. Visual PSOs shall immediately communicate all observations of
marine mammals to the on-duty acoustic PSO(s), including any
determination by the PSO regarding species identification, distance,
and bearing and the degree of confidence in the determination. Any
observations of marine mammal species by crew members aboard any vessel
associated with the survey shall be relayed to the PSO team.
PSOs will establish and monitor applicable exclusion zones. During
use of HRG acoustic sources (i.e., anytime the acoustic source is
active), occurrences of marine mammal species approaching the relevant
exclusion zone will be communicated to the operator to prepare for the
potential shutdown of the acoustic source. Exclusion zones are defined,
depending on the species and context, below:
500 m (1,640 ft) exclusion zone for North Atlantic right
whales;
200 m (656 ft) exclusion zone for sei and fin whales; and
100 m (328 ft) exclusion zone for other large cetaceans
(i.e., humpback whale, minke whale, pilot whale, Risso's dolphin).
The Level B harassment zone represents the zone within which marine
mammals would be considered taken by Level B harassment and will
encompass a distance of 200 m (656 ft) from survey equipment for all
marine mammal species.
Pre-Clearance
Avangrid will implement a 30-minute clearance period of the
exclusion zones. This will help ensure marine mammals are not in the
exclusion zones prior to startup of HRG equipment. During this period
the exclusion zones will be monitored by the PSOs, using the
appropriate visual technology for a 30-minute period. The intent of
pre-clearance observation is to ensure no marine mammal species are
observed within the exclusion zones prior to the beginning of operation
of HRG equipment. A PSO conducting pre-clearance observations must be
notified immediately prior to initiating start of HRG equipment and the
operator must receive confirmation from the PSO to proceed.
Activation of HRG equipment may not be initiated if any marine
mammal is observed within the applicable exclusion zones as described
above. If a marine mammal is observed within the applicable exclusion
zone during the 30 minute pre-clearance period, activation of HRG
equipment may not begin until the animal(s) has been observed exiting
the zones or until an additional time period has elapsed with no
further sightings (15 minutes for small delphinoid cetaceans and 30
minutes for all other species). Activation of HRG equipment may occur
at times of poor visibility, including nighttime, if continuous visual
observation and has occurred with no detections of marine mammals in
the 30 minutes prior to beginning of start-up.
Shutdown Procedures
An immediate shutdown of the HRG survey equipment will be required
if a marine mammal is sighted at or within its respective exclusion
zone to minimize or avoid behavioral impacts to ESA-listed species. The
vessel operator must comply immediately with any call for shutdown by
the lead PSO. The operator must establish and maintain clear lines of
communication directly between PSOs on duty and crew controlling the
acoustic source to ensure that shutdown commands are conveyed swiftly
while allowing PSOs to maintain watch. When shutdown is called for by a
PSO, the acoustic source must be immediately deactivated and any
dispute resolved only following deactivation.
Should there be any 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 or
one of the species with a larger exclusion zone), visual PSOs may use
best professional judgment in making the decision to call for a
shutdown. 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 200 m Level B harassment zone, shutdown must occur.
Subsequent restart of the survey equipment can be initiated if the
animal has been observed exiting its respective exclusion zone within
30 minutes of the shutdown or an additional time period has elapsed
with no further sighting (i.e., 15 minutes for small odontocetes and 30
minutes for all other species).
If the acoustic source is shut down for reasons other than
mitigation (e.g., mechanical difficulty) for less than 30 minutes, it
may be activated again without pre-clearance protocols, if PSOs have
maintained constant observation and no detections of any marine mammal
have occurred within the respective exclusion zones.
Vessel Strike Avoidance
In order to avoid striking animals, vessel operators and crews must
maintain a vigilant watch for all marine mammal species and slow down,
stop their vessel, or alter course, as appropriate and regardless of
vessel size. 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
distinguish marine mammal species from other phenomena and 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. Vessel strike avoidance measures will include the
following:
[[Page 17402]]
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
(DMA) when in effect, and the Mid-Atlantic Seasonal Management Areas
(SMA) (from November 1 through April 30). See 50 CFR 224.105 and
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,
regardless of location, 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 all other baleen whales and sperm 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 marine mammals 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.
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
effecting the least practicable impact on the affected species or
stocks and their habitat, paying particular attention to rookeries,
mating grounds, and areas of similar significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, Section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104(a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present in the
proposed action area. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) Action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the action; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and
Mitigation and monitoring effectiveness.
Proposed Monitoring and Reporting Measures
Visual Monitoring
Visual monitoring shall be conducted by NMFS-approved PSOs. PSO
resumes shall be provided to NMFS for approval prior to commencement of
the survey. Avangrid must use independent, dedicated, trained PSOs,
meaning that the PSOs must be employed by a third-party observer
provider, must 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).
Observations shall take place from the highest available vantage
point on the survey vessel. General 360-degree scanning shall occur
during the monitoring periods, and target scanning by the PSO shall
occur when alerted of a marine mammal presence. An observer team
comprising a minimum of four NMFS-approved PSOs, operating in shifts,
will be stationed aboard the survey vessel. PSO's will work in shifts
such that no one monitor will work more than 4 consecutive hours
without a 2-hour break or longer than 12 hours during any 24-hour
period. During daylight hours the PSOs will rotate in shifts of 1 on
and 3 off, and during nighttime operations PSOs will work in pairs.
PSOs must have all equipment (including backup equipment) needed to
adequately perform necessary tasks, including accurate determination of
distance and bearing to observed marine mammals. PSOs will be equipped
with binoculars and have the ability to estimate distances to marine
mammals located in proximity to their established zones using range
finders. Reticulated binoculars will also be available to PSOs for use
as appropriate based on conditions and visibility to support the siting
and monitoring of marine species. Cameras of appropriate quality will
be used for photographs and video to record sightings and verify
species identification. Each PSO must have a camera and backup cameras
should be available. During night operations, night-vision equipment
(night-vision goggles with thermal clip-ons) and infrared technology
will be used. Position data will be recorded using hand-held or vessel
global positioning system (GPS) units for each sighting. Radios for
each PSO are required in order to communicate among vessel crew and
PSOs. PSO must also have compasses and any other tools necessary to
perform other PSO tasks.
[[Page 17403]]
PSOs shall be responsible for visually monitoring and identifying
marine mammals approaching or entering the established monitoring zones
as well as beyond the monitoring zones to the maximum extent possible.
PSOs will record animals both within and beyond the monitoring zones
during survey activities.
Data on all PSO observations must be recorded based on standard PSO
collection requirements. PSOs must use standardized data forms, whether
hard copy or electronic. This shall include the following:
Vessel names (source vessel and other vessels associated
with survey), vessel size and type, maximum speed capability of vessel,
port of origin, and call signs;
PSO names and affiliations;
Dates of departures and returns to port with port name;
Date and participants of PSO briefings;
Dates and times (Greenwich Mean Time) of survey effort and
times corresponding with PSO effort;
Vessel location (latitude/longitude) when survey effort
begins and ends; vessel location at beginning and end of visual PSO
duty shifts;
Vessel heading and speed at beginning and end of visual
PSO duty shifts and upon any line change;
Environmental conditions while on visual survey (at
beginning and end of PSO shift and whenever conditions change
significantly), including wind speed and direction, Beaufort sea state,
Beaufort wind force, swell height, weather conditions, cloud cover, sun
glare, and overall visibility to the horizon;
Factors that may be contributing to impaired observations
during each PSO shift change or as needed as environmental conditions
change (e.g., vessel traffic, equipment malfunctions);
Survey activity information, such as acoustic source power
output while in operation, and any other notes of significance (i.e.,
pre-ramp-up survey, ramp-up, shutdown, testing, ramp-up completion, end
of operations, etc.);
If a marine mammal is sighted, the following information
should be reported:
(a) Watch status (sighting made by PSO on/off effort,
opportunistic, crew, alternate vessel/platform);
(b) PSO who sighted the animal;
(c) Time of sighting;
(d) Vessel location at time of sighting;
(e) Water depth;
(f) Direction of vessel's travel (compass direction);
(g) Direction of animal's travel relative to the vessel;
(h) Pace of the animal;
(i) Estimated distance to the animal and its heading relative to
vessel at initial sighting;
(j) Identification of the animal (e.g., genus/species, lowest
possible taxonomic level, or unidentified); also note the composition
of the group if there is a mix of species;
(k) Estimated number of animals (high/low/best);
(l) Estimated number of animals by cohort (adults, yearlings,
juveniles, calves, group composition, etc.);
(m) Description (as many distinguishing features as possible of
each individual seen, including length, shape, color, pattern, scars or
markings, shape and size of dorsal fin, shape of head, and blow
characteristics);
(n) Detailed behavior observations (e.g., number of blows, number
of surfaces, breaching, spyhopping, diving, feeding, traveling; as
explicit and detailed as possible; note any observed changes in
behavior);
(o) Animal's closest point of approach and/or closest distance from
the center point of the acoustic source;
(p) Platform activity at time of sighting (e.g., deploying,
recovering, testing, data acquisition, other); and
(q) Description of any actions implemented in response to the
sighting (e.g., delays, shutdown, ramp-up, speed or course alteration,
etc.) and time and location of the action.
Proposed Reporting Measures
Within 90 days after completion of survey activities, a final
report will be provided to NMFS that fully documents the methods and
monitoring protocols, summarizes the data recorded during monitoring,
estimates the number of marine mammals estimated to have been taken
during survey activities, and provides an interpretation of the results
and effectiveness of all mitigation and monitoring. All raw
observational data shall be made available to NMFS. The draft report
must be accompanied by a certification from the lead PSO as to the
accuracy of the report, and the lead PSO may submit directly to NMFS a
statement concerning implementation and effectiveness of the required
mitigation and monitoring. Any recommendations made by NMFS must be
addressed in the final report prior to acceptance by NMFS. A final
report must be submitted within 30 days following resolution of any
comments on the draft report.
Notification of Injured or Dead Marine Mammals
In the unanticipated event that the specified HRG activities lead
to an injury of a marine mammal (Level A harassment) or mortality
(e.g., ship-strike, gear interaction, and/or entanglement), Avangrid
would immediately cease the specified activities and report the
incident to the Chief of the Permits and Conservation Division, Office
of Protected Resources and the NMFS Southeast Regional Stranding
Coordinator. The report would include the following information:
Time, date, and location (latitude/longitude) of the
incident;
Name and type of vessel involved;
Vessel's speed during and leading up to the incident;
Description of the incident;
Status of all sound source use in the 24 hours preceding
the incident;
Water depth;
Environmental conditions (e.g., wind speed and direction,
Beaufort sea state, cloud cover, and visibility);
Description of all marine mammal observations in the 24
hours preceding the incident;
Species identification or description of the animal(s)
involved;
Fate of the animal(s); and
Photographs or video footage of the animal(s) (if
equipment is available).
Activities would not resume until NMFS is able to review the
circumstances of the event. NMFS would work with Avangrid to minimize
reoccurrence of such an event in the future. Avangrid would not resume
activities until notified by NMFS.
In the event that Avangrid discovers an injured or dead marine
mammal and determines that the cause of the injury or death is unknown
and the death is relatively recent (i.e., in less than a moderate state
of decomposition), Avangrid would immediately report the incident to
the Chief of the Permits and Conservation Division, Office of Protected
Resources and the NMFS Southeast Regional Stranding Coordinator. The
report would include the same information identified in the paragraph
above. Activities would be able to continue while NMFS reviews the
circumstances of the incident. NMFS would work with Avangrid to
determine if modifications in the activities are appropriate.
In the event that Avangrid discovers an injured or dead marine
mammal and determines that the injury or death is not associated with
or related to the activities authorized in the IHA (e.g., previously
wounded animal, carcass with moderate to advanced decomposition, or
scavenger damage), Avangrid would report the incident to the Chief of
the Permits and Conservation Division, Office of
[[Page 17404]]
Protected Resources, and the NMFS Southeast Regional Stranding
Coordinator, within 24 hours of the discovery. Avangrid would provide
photographs or video footage (if available) or other documentation of
the stranded animal sighting to NMFS. Avangrid may continue its
operations under such a case.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (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, this introductory discussion of our analyses
applies to all the species listed in Table 8, given that many of the
anticipated effects of this project on different marine mammal stocks
are expected to be relatively similar in nature. Where there are
meaningful differences between species or stocks, or groups of species,
in anticipated individual responses to activities, impact of expected
take on the population due to differences in population status, or
impacts on habitat, they are described independently in the analysis
below.
As discussed in the ``Potential Effects of the Specified Activity
on Marine Mammals and Their Habitat'' section, PTS, masking, non-
auditory physical effects, and vessel strike are not expected to occur.
Marine mammal habitat may be impacted by elevated sound levels but
these impacts would be short term. Feeding behavior is not likely to be
significantly impacted. 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 availability of
similar habitat and resources in the surrounding area, and the lack of
important or unique marine mammal habitat, 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. Additionally, there are no feeding areas
or mating grounds known to be biologically important to marine mammals
within the proposed project area with the exception of a migratory BIA
for North Atlantic right whales described below.
Biologically Important Areas (BIA)
The proposed survey area includes a biologically important
migratory area for North Atlantic right whales (effective March-April
and November-December) that extends from Massachusetts to Florida
(LaBrecque, et al., 2015). As previously noted, no take of North
Atlantic right whales has been proposed, and HRG survey operations will
be required to shut down at 500 m to further minimize any potential
effects to this species. The fact that the spatial acoustic footprint
of the proposed survey is very small relative to the spatial extent of
the available migratory habitat leads us to expect that right whale
migration will not be impacted by the proposed survey.
Unusual Mortality Events (UME)
A UME is defined under the MMPA as a stranding that is unexpected;
involves a significant die-off of any marine mammal population; and
demands immediate response. Two UMEs are ongoing and under
investigation relevant to the HRG survey area for species for which
authorization of take is proposed. These involve humpback whales and
minke whales. There is currently no direct connection between the UMEs,
as there is no evident cause of stranding or death that is common
across the species involved in the UMEs. Additionally, strandings
across the two species are not clustering in space or time. We are
proposing to take only limited numbers of humpback (10) and minke whale
(17) by Level B harassment in the form of minor, short-term behavioral
modifications that are unlikely to directly or indirectly result in
strandings or mortality.
Based on the foregoing preliminary information, direct physical
interactions (ship strikes and entanglements) appear to be responsible
for many of the UME mortalities recorded. The HRG survey with the
proposed mitigation and monitoring is not likely to result in any
mortalities. Fishing gear and in-water lines will not be employed by
the survey vessel, and ship speed and avoidance mitigation measures
will minimize risk of ship strikes.
The proposed mitigation measures are expected to reduce the number
and/or severity of takes by preventing animals from being exposed to
sound levels that have the potential to cause Level B harassment during
HRG survey activities. Vessel strike avoidance requirements will
further mitigate potential impacts to marine mammals during vessel
transit to and within the survey area.
Avangrid did not request, and NMFS is not proposing to authorize,
take of marine mammals by serious injury or mortality. NMFS expects
that most takes would primarily consist of short-term Level B
behavioral harassment in the form of temporary vacating of the area or
decreased foraging (if such activity were occurring). These reactions
are considered to be of low severity and with no lasting biological
consequences (e.g., Southall et al., 2007). Since the source is mobile,
a specified area would be ensonified by sound levels that could result
in take for only a short period. Additionally, required mitigation
measures would reduce exposure to sound that could result in
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 injury is anticipated or authorized;
Feeding behavior is not likely to be significantly
impacted as effects on species that serve as prey species for marine
mammals from the proposed 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;
[[Page 17405]]
Take is anticipated to be by Level B behavioral harassment
only, 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 migration of the North Atlantic right whale,
migration would not be affected since project activities would occur in
such a comparatively small area. In addition, mitigation measures will
be required to shut down sound sources at 500 m to further minimize any
potential for effects to this species; and
The proposed mitigation measures, including visual
monitoring and shutdowns, are expected to minimize potential impacts to
marine mammals, particularly in light of the small size of the take
zones.
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 relative to the species.
The numbers of marine mammals that we propose for authorization to
be taken, for all species and stocks, would be considered small
relative to the relevant stocks or populations (less than 3 percent for
the bottlenose dolphin Western North Atlantic, southern migratory
coastal stock and less than one percent for all other species and
stocks proposed for authorization). See 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 sizes of the affected species
or stocks.
Unmitigable Adverse Impact Analysis and Determination
There are no relevant subsistence uses of marine mammals implicated
by this action. Therefore, NMFS has determined that the total taking of
affected species or stocks would not have an unmitigable adverse impact
on the availability of such species or stocks for taking for
subsistence purposes.
Endangered Species Act (ESA)
Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 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.
No incidental take of ESA-listed species is proposed for
authorization or expected to result from this activity. Therefore, NMFS
has determined that formal consultation under section 7 of the ESA is
not required for this action.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to Avangrid for HRG survey activities during geophysical
survey activities off the Coast of Virginia and North Carolina from
June 1, 2019, through May 31, 2020, provided the previously mentioned
mitigation, monitoring, and reporting requirements are incorporated. A
draft of the proposed IHA can be found at https://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 the proposed HRG
survey. We also request comment on the potential for 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 our final decision on the request for MMPA authorization.
On a case-by-case basis, NMFS may issue a one-year IHA renewal with
an expedited public comment period (15 days) when (1) another year of
identical or nearly identical activities as described in the Specified
Activities section is planned or (2) the activities would not be
completed by the time the IHA expires and a second IHA would allow for
completion of the activities beyond that described in the Dates and
Duration section, provided all of the following conditions are met:
A request for renewal is received no later than 60 days
prior to expiration of the current IHA.
The request for renewal must include the following:
(1) An explanation that the activities to be conducted under the
proposed Renewal 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
because only a subset of the initially analyzed activities remain to be
completed under the Renewal); and
(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: April 22, 2019.
Catherine Marzin,
Deputy Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2019-08361 Filed 4-24-19; 8:45 am]
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