Notice2021-15243
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Site Characterization Surveys Off the Coast of Massachusetts and Rhode Island
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
July 19, 2021
Effective
July 1, 2021
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
In accordance with the regulations implementing the Marine Mammal Protection Act (MMPA) as amended, notification is hereby given that NMFS has issued an incidental harassment authorization (IHA) to Mayflower Wind Energy LLC (Mayflower) to incidentally harass, by Level B harassment only, marine mammals during site characterization surveys off the coast of Massachusetts and Rhode Island in the area of the Commercial Lease of Submerged Lands for Renewable Energy Development on the Outer Continental Shelf (OCS-A 0521) and along a potential submarine cable route to landfall at Falmouth, Massachusetts and Narragansett Bay.
Full Text
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<title>Federal Register, Volume 86 Issue 135 (Monday, July 19, 2021)</title>
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[Federal Register Volume 86, Number 135 (Monday, July 19, 2021)]
[Notices]
[Pages 38033-38052]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2021-15243]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XB203]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Site Characterization Surveys Off
the Coast of Massachusetts and Rhode Island
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; issuance of an incidental harassment authorization.
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SUMMARY: In accordance with the regulations implementing the Marine
Mammal Protection Act (MMPA) as amended, notification is hereby given
that NMFS has issued an incidental harassment authorization (IHA) to
Mayflower Wind Energy LLC (Mayflower) to incidentally harass, by Level
B harassment only, marine mammals during site characterization surveys
off the coast of Massachusetts and Rhode Island in the area of the
Commercial Lease of Submerged Lands for Renewable Energy Development on
the Outer Continental Shelf (OCS-A 0521) and along a potential
submarine cable route to landfall at Falmouth, Massachusetts and
Narragansett Bay.
DATES: This authorization is effective from July 1, 2021 through June
30, 2022.
FOR FURTHER INFORMATION CONTACT: Robert 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: <a href="https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a>. In case of problems accessing these
documents, please call the contact listed above.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are issued or, if the taking is limited to harassment, a notice of a
proposed incidental take authorization may be provided to the public
for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of the species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the mitigation,
monitoring and reporting of the takings are set forth.
Summary of Request
On October 23, 2020, NMFS received a request from Mayflower for an
IHA to take marine mammals incidental to site characterization surveys
in the area of the Commercial Lease of Submerged Lands for Renewable
Energy Development on the Outer Continental Shelf (OCS-A 0521; Lease
Area) and a submarine export cable route connecting the Lease Area to
landfall in Falmouth, Massachusetts. A revised application was received
on December 15, 2020. NMFS deemed that request to be adequate and
complete on February 1, 2021. A notice of a proposed IHA was published
in the Federal Register on March 1, 2021 (85 FR 11930). After
publication of the proposed IHA Mayflower determined that they needed
to add an additional export cable route corridor to their survey plan.
Mayflower originally had proposed two separate but parallel export
cable routes that would run north from the Lease Area between Martha's
Vineyard and Nantucket islands through Nantucket Sound to a landfall
location in Falmouth, MA. As part of the modification, Mayflower plans
to eliminate the easternmost export cable corridor route between
Martha's Vineyard and Nantucket and replace it with an export cable
corridor route that runs south of Martha's Vineyard through
Narragansett Bay to an unspecified landfall location in the Bay. The
westernmost export cable route corridor to Falmouth, MA remains
unchanged from the initial proposed IHA. Therefore, a final IHA was not
issued and Mayflower submitted a modified application on April 19,
2021. NMFS published a notice of a modified proposed IHA on May 20,
2021 (86 FR 27393). Mayflower's request was for take of a small number
of 14 species of marine mammals by Level B harassment only. Neither
Mayflower nor NMFS expects serious injury or mortality to result from
this activity and, therefore, an IHA is appropriate.
NMFS previously issued an IHA to Mayflower for similar work (85 FR
45578; July 29, 2020) in the same Lease Area and along the same
submarine cable route connected to Falmouth, MA that is effective from
July 23, 2020 through July 22, 2021. However, the survey activity
conducted under that IHA concluded on October 23, 2020. Mayflower
submitted a marine mammal monitoring report and complied with all the
requirements (e.g., mitigation, monitoring, and reporting) of the
previous IHA. Information regarding their monitoring results may be
found in the Estimated Take section.
Description of the Specified Activity
Mayflower plans to conduct marine site characterization surveys,
including high-resolution geophysical (HRG) and geotechnical surveys,
in the area of Commercial Lease of Submerged Lands for Renewable Energy
Development on the Outer Continental Shelf #OCS-A 0521 (Lease Area) and
along potential submarine cable routes to landfall at Falmouth,
Massachusetts and Narragansett Bay.
The objective of the activities is to acquire high resolution
geophysical (HRG) and geotechnical data on the bathymetry, seafloor
morphology, subsurface geology, environmental/biological sites,
seafloor obstructions, soil conditions, and locations of any man-made,
historical or archaeological resources within Lease Area OCS-A 0521
which is located approximately 20 nautical miles (38 kilometers (km))
south-southwest of Nantucket, Massachusetts covering approximately 515
km\2\ and along the two planned export cable route corridors described
above.
[[Page 38034]]
The total duration of HRG survey activities would be approximately
471 survey days with a total trackline distance of 14,350 kilometers
(km). Each day that a survey vessel is operating counts as a single
survey day. This schedule is based on 24-hour operations in the
offshore, deep-water portion of the Lease Area, and 12-hour operations
in shallow-water and nearshore areas of the export cable routes. Some
shallow-water HRG activities will occur only during daylight hours.
Mayflower would begin survey activities in July 2021 and conclude
operations by December 31, 2021. The IHA is effective for 1 year from
the date of issuance.
Underwater sound resulting from Mayflower's planned activities,
specifically certain acoustic sources planned for use during its HRG
surveys, has the potential to result in incidental take of marine
mammals in the form of behavioral harassment.
The HRG survey activities planned by Mayflower are described in
detail in the notice of modified proposed IHA (86 FR 27393; May 20,
2021). Since that time, no changes have been made to the planned HRG
survey activities. Therefore, a detailed description is not provided
here. Please refer to that Federal Register notice for the description
of the specific activity. Mitigation, monitoring, and reporting
measures are described in detail later in this document (please see
Mitigation and Monitoring and Reporting below). The HRG equipment
planned for use is shown in Table 1.
Table 1--Summary of HRG Survey Equipment Planned for Use That Could Result in Take of Marine Mammals
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Operating Pulse
Specific HRG equipment frequency Source level Beamwidth Typical pulse repetition
range (kHz) (dB rms) (degrees) duration (ms) rate (Hz)
----------------------------------------------------------------------------------------------------------------
Sparker
----------------------------------------------------------------------------------------------------------------
Geomarine Geo-Spark 400 tip 800 0.01-1.9 203 180 3.4 2
J system.......................
Applied Acoustics Dura-Spark UHD 0.01-1.9 203 180 3.4 2
400 tips, up to 800 J..........
----------------------------------------------------------------------------------------------------------------
Boomer
----------------------------------------------------------------------------------------------------------------
Applied Acoustics S-Boom Triple 0.01-5 205 61 0.6 3
Plate..........................
Applied Acoustics S-Boom........ 0.01-5 195 98 0.9 3
----------------------------------------------------------------------------------------------------------------
Sub-bottom Profiler
----------------------------------------------------------------------------------------------------------------
Edgetech 3100 with SB-2-16S 2-16 179 51 9.1 10
towfish........................
Edgetech DW-106................. 1-6 176 66 14.4 10
Teledyne Benthos Chirp III-- 2-7 199 82 5.8 10
towfish........................
Knudson Pinger SBP.............. 15 180 71 4 2
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Comments and Responses
A notice of NMFS's modified proposal to issue an IHA to Mayflower
was published in the Federal Register on May 20, 2021 (86 FR 27393).
That notice described, in detail, Mayflower's activity, the marine
mammal species that may be affected by the activity, and the
anticipated effects on marine mammals. During the 30-day comment
period, NMFS received comments from a group of environmental non-
governmental organizations (ENGOs) including the Natural Resources
Defense Council, Conservation Law Foundation, National Wildlife
Federation, Defenders of Wildlife, Southern Environmental Law Center,
Surfrider Foundation, Mass Audubon, Friends of the Earth, International
Fund for Animal Welfare, NY4WHALES, WDC Whale and Dolphin Conservation,
Marine Mammal Alliance Nantucket and Gotham Whale.
Comment 1: The ENGOs stressed that NMFS must ensure undisturbed
access to foraging habitat to adequately protect North Atlantic right
whales since North Atlantic right whales employs a ``high-drag''
foraging strategy that enables them to selectively target high-density
prey patches, but is energetically expensive.
Response: NMFS stated in the modified proposed IHA, that part of
the Project Area coincides directly with year-round ``core'' North
Atlantic right whale foraging habitat (Oleson et al., 2020) south of
Martha's Vineyard and Nantucket islands where both visual and acoustic
detections of North Atlantic right whales indicate a nearly year-round
presence (Oleson et al., 2020). NMFS notes that prey for North Atlantic
right whales are mobile and broadly distributed throughout the project
area; therefore, North Atlantic right whales are expected to be able to
resume foraging once they have moved away from any areas with
disturbing levels of underwater noise. There is ample foraging habitat
adjacent to the Project Area that is not ensonified by HRG sources. For
example, in the fall of 2019 and 2020, North Atlantic right whales were
particularly attracted to Nantucket Shoals, located to the east of the
Project Area. Furthermore, the spatial acoustic footprint of the survey
is very small relative to the spatial extent of the available foraging
habitat. Finally, we have established a 500-m shutdown zone for North
Atlantic right whales, which is more than three times as large as the
greatest Level B harassment isopleth calculated for the specified
activities for this IHA.
Comment 2: The ENGO's noted that harbor porpoises are particularly
sensitive to noise, and, therefore, impacts to this species must be
minimized and mitigated to the full extent practicable during offshore
wind siting and development activities.
Response: Harbor porpoises are classified as high-frequency
cetaceans (NMFS 2018) and are the hearing group with the lowest PTS
onset thresholds, with maximum susceptibility to frequencies between 20
and 40 kHz (susceptibility decreases with outside this frequency
range). However, the largest modeled distance to the Level A harassment
threshold of for HF cetaceans was 57 m. Furthermore, this is a
conservative assessment given that the model used to determine PTS
isopleths treats all devices as impulsive and results in significant
overestimates for non-impulsive devices, since PTS
[[Page 38035]]
onset thresholds are lower for impulsive sources compare to non-
impulsive sources. Level A harassment would also be more likely to
occur at close approach to the sound source or as a result of longer
duration exposure to the sound source, and mitigation measures--
including a 100 m exclusion zone (EZ) for harbor porpoises--are
expected to minimize the potential for close approach or longer
duration exposure to active HRG sources. In addition, harbor porpoises
are known to be behaviorally sensitive species, in that they respond to
comparatively lower received levels and are known to avoid vessels and
other sound sources and, therefore, harbor porpoises would also be
expected to avoid a sound source prior to that source reaching a level
that would result in injury (Level A harassment). Therefore, NMFS has
determined that take of harbor porpoises or any other animal by Level A
harassment is unlikely to occur and has not authorized any such takes.
Any takes by Level B harassment are anticipated to be limited to brief
startling reactions and/or temporary avoidance of the Project Area.
Further, appropriate mitigation measures have been included to ensure
the least practicable adverse impact on harbor porpoises and other
marine mammal species.
Comment 3: The ENGOs recommended that NMFS incorporate additional
data sources into calculations of marine mammal density and take and
that NMFS must ensure all available data are used to ensure that any
potential shifts in North Atlantic right whale habitat usage are
reflected in estimations of marine mammal density and take. The ENGOs
asserted in general that the density models used by NMFS do not fully
reflect the abundance, distribution, and density of marine mammals for
the U.S. East Coast and therefore result in an underestimate of take.
Response: Habitat-based density models produced by the Duke
University Marine Geospatial Ecology Lab (MGEL) (Roberts et al., 2016,
2017, 2018, 2020) represent the best available scientific information
concerning marine mammal occurrence within the U.S. Atlantic Ocean.
Density models were originally developed for all cetacean taxa in the
U.S. Atlantic (Roberts et al., 2016); more information, including the
model results and supplementary information for each of those models,
is available at <a href="https://seamap.env.duke.edu/models/Duke/EC/">https://seamap.env.duke.edu/models/Duke/EC/</a> EC/. These
models provided key improvements over previously available information,
by incorporating additional aerial and shipboard survey data from NMFS
and from other organizations collected over the period 1992-2014,
incorporating 60 percent more shipboard and 500 percent more aerial
survey hours than did previously available models; controlling for the
influence of sea state, group size, availability bias, and perception
bias on the probability of making a sighting; and modeling density from
an expanded set of 8 physiographic and 16 dynamic oceanographic and
biological covariates. In subsequent years, certain models have been
updated on the basis of additional data as well as methodological
improvements. In addition, a new density model for seals was produced
as part of the 2017-18 round of model updates.
Of particular note, Roberts et al., (2020) further updated density
model results for North Atlantic right whales by incorporating
additional sighting data and implementing three major changes:
Increasing spatial resolution, generating monthly estimates on three
time periods of survey data, and dividing the study area into 5
discrete regions. This most recent update--model version nine for North
Atlantic right whales--was undertaken with the following objectives
(Roberts et al., 2020):
<bullet> To account for recent changes to right whale
distributions, the model should be based on survey data that extend
through 2018, or later if possible. In addition to updates from
existing collaborators, data should be solicited from two survey
programs not used in prior model versions including aerial surveys of
the Massachusetts and Rhode Island Wind Energy Areas led by New England
Aquarium (Kraus et al., 2016), spanning 2011-2015 and 2017-2018 and
recent surveys of New York waters, either traditional aerial surveys
initiated by the New York State Department of Environmental
Conservation in 2017, or digital aerial surveys initiated by the New
York State Energy Research and Development Authority in 2016, or both.
<bullet> To reflect a view in the right whale research community
that spatiotemporal patterns in right whale density changed around the
time the species entered a decline in approximately 2010, consider
basing the new model only on recent years, including contrasting
``before'' and ``after'' models that might illustrate shifts in
density, as well as a model spanning both periods, and specifically
consider which model would best represent right whale density in the
near future.
<bullet> To facilitate better application of the model to near-
shore management questions, extend the spatial extent of the model
farther in-shore, particularly north of New York.
<bullet> Increase the resolution of the model beyond 10 kilometers
(km), if possible.
All of these objectives were met in developing the most recent
update to the North Atlantic right whale density model.
As noted above, NMFS has determined that the Roberts et al. suite
of density models represent the best available scientific information.
However, NMFS acknowledges that there may be additional data that is
not reflected in the models and that may inform our analyses, whether
because the data were not available to the model authors or because the
data is more recent than the latest model version for a specific taxon.
The ENGOs pointed to additional data that can be obtained from
sightings databases, passive acoustic monitoring efforts, aerial
surveys, and autonomous vehicles. The ENGO's pointed specifically to
monthly standardized marine mammal aerial surveys flown in the
Massachusetts and Rhode Island and Massachusetts Wind Energy Areas by
the New England Aquarium from October 2018 through August 2019 and
March 2020 through July 2021. The 2018-2019 New England Aquarium study
showed North Atlantic right whales were primarily found to the east of
the Project Area although, distribution changed seasonally. There was
only one North Atlantic right whale sighted in the Lease Area while
limited numbers were found north of the Lease Area in the export cable
corridor route occurring between Martha's Vineyard and Nantucket
heading to a landfall location in Falmouth, MA. Sightings of north
Atlantic right whales occurred in these areas only during the spring
while Mayflower plans to conduct operations from June 2021 to December
31, 2021. Information on the results from the 2020-2021 aerial survey
was unavailable at the time of the issuance of the final IHA. The
commenters also referenced a study funded by the Bureau of Offshore
Energy Management (BOEM) using an autonomous vehicle for real-time
acoustical monitoring of marine mammals from December 2019 through
March 2020 and again from December 2020 through February 2021 on Cox
Ledge, located approximately 35 miles east of Montauk Point, New York
between Block Island and Martha's Vineyard. Note that only a small
portion of BOEM's acoustic study area overlapped with Mayflower's
export cable corridor route running to Narraganset Bay. Between
November 15, 2020 and February 26, 2021 (103 days)
[[Page 38036]]
North Atlantic right whales were acoustically detected on 19 days and
possibly detected on an additional 12 days. Most of these detections
and possible detections occurred south of Mayflower's planned export
cable corridor route outside of the Project Area. No North Atlantic
right whales were detected in BOEM's study area between March 25, 2021
and June 29, 2021 (96 days). The data from these recent studies does
not indicate that NMFS should employ seasonal restrictions or alter any
of the required mitigation and monitoring requirements, particularly as
NMFS considers impacts from these types of survey operations to be near
de minimis and that Mayflower will not be conducting survey operations
during the spring. It would be difficult to draw any qualitative
conclusions from these study results given that most of the
observations and detections occurred outside of Mayflower's Project
Area.
NMFS will review any other recommended data sources that become
available to evaluate their applicability in a quantitative sense
(e.g., to an estimate of take numbers) and, separately, to ensure that
relevant information is considered qualitatively when assessing the
impacts of the specified activity on the affected species or stocks and
their habitat. NMFS will continue to use the best available scientific
information, and we welcome future input from interested parties on
data sources that may be of use in analyzing the potential presence and
movement patterns of marine mammals, including North Atlantic right
whales, in U.S. Atlantic waters.
While the ENGO's referenced additional data, no specific
recommendations were made with regard to use of this information in
informing the take estimates. Rather, the commenters suggested that
NMFS should ``collate and integrate these and more recent data sets to
more accurately reflect marine mammal presence for future IHAs and
other work.'' NMFS would welcome in the future constructive suggestions
as to how these objectives might be more effectively accomplished. NMFS
used the best scientific information available at the time the analyses
for the proposed and modified proposed IHAs were conducted, and has
considered all available data, including sources referenced by the
commenters, in reaching its determinations in support of issuance of
the IHA requested by Mayflower.
Comment 4: The ENGOs recommended that NMFS require the
implementation of seasonal restrictions on site characterization
activities that have the potential to injure or harass the North
Atlantic right whale from December 1, 2021 through April 30, 2022. The
ENGOs further note that they consider source levels greater than 180 dB
re 1 [mu]Pa (SPL) at 1-meter at frequencies between 7 Hz and 35 kHz to
be potentially harmful to low-frequency cetaceans.
Response: NMFS is concerned about the status of the North Atlantic
right whale, given that a UME has been in effect for this species since
June of 2017 and that there have been a number of recent mortalities.
NMFS appreciates the value of seasonal restrictions under some
circumstances. However, in this case, we have determined seasonal
restrictions are not warranted since NMFS considers impacts from these
types of survey operations to be near de minimis. NMFS, however, is
requiring Mayflower to comply with restrictions associated with
identified seasonal management areas (SMAs) and they must comply with
dynamic management areas (DMAs), if any DMAs are established near the
Project Area. Furthermore, we have established a 500-m shutdown zone
for North Atlantic right whales, which is more than three times as
large as the greatest Level B harassment isopleth calculated for the
specified activities for this IHA (141 m). Take estimation
conservatively assumes that these acoustic sources will operate on all
survey days although it is probable that Mayflower will only use
sparkers on a subset of survey days, and on the remaining days utilize
HRG equipment with considerably smaller Level B harassment isopleths.
Therefore, the number of Level B harassment takes is likely an
overestimate. Finally, significantly shortening Mayflower's work season
is impracticable given the number of survey days planned for the
specified activity for this IHA.
It is unclear how the commenters determined that source levels
greater than 180 dB re 1 [mu]Pa (SPL) are potentially harmful to low-
frequency cetaceans. NMFS historically applied a received level (not
source level) root mean square (rms) threshold of 180 dB SPL as the
potential for marine mammals to incur PTS (i.e., Level A (injury)
harassment); however, in 2016, NMFS published it Technical Guidance for
Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing
which updated the 180 dB SPL Level A harassment threshold. Since that
time, NMFS has been applying dual threshold criteria based on both peak
and a weighted (to account for marine mammal hearing) cumulative sound
exposure level. NMFS released a revised version of the Technical
Guidance in 2018. We encourage the ENGOs to review the Technical
Guidance available at <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a> to inform
future reviews of any proposed IHA on which they may wish to comment.
As described in the Estimated Take section, NMFS has established a PTS
(Level A harassment) threshold of 183 dB cumulative SEL for low
frequency specialists, and a right whale would need to approach within
2 meters of the source to potentially incur PTS from the largest
source.
Comment 5: The ENGOs recommended that NMFS should prohibit the
commencement of geophysical surveys at night to maximize the
probability that marine mammals are detected and confirmed clear of the
EZ. The commenters asserted that initiation of work should occur with
ramp-up, only during daylight hours.
Response: NMFS acknowledges the limitations inherent in detection
of marine mammals at night. However, no injury is expected to result
even in the absence of mitigation, given the characteristics of the
sources planned for use (supported by the very small estimated Level A
harassment zones). The ENGOs do not provide any support for the
apparent contention that injury is a potential outcome of these
activities. Regarding Level B harassment, any potential impacts would
be limited to short-term behavioral responses, as described in greater
detail herein. The commenters establish that the status of North
Atlantic right whales in particular is precarious. NMFS agrees in
general with the discussion of this status provided by the commenters.
Note that NMFS considers impacts from this category of survey
operations to be near de minimis, with the potential for Level A
harassment for any species to be discountable and the severity of Level
B harassment (and, therefore, the impacts of the take event on the
affected individual), if any, to be low. NMFS is also requiring
Mayflower to deploy two PSOs during nighttime hours who must have
access to night-vision equipment (i.e., night-vision goggles and/or
infrared technology). Given these factors, NMFS does not believe that
there is a need for more restrictive mitigation requirements.
Restricting surveys in the manner suggested by the commenters may
reduce marine mammal exposures by some degree in the short term, but
would not result in any significant
[[Page 38037]]
reduction in either intensity or duration of noise exposure. Vessels
would also potentially be on the water for an extended time introducing
noise into the marine environment. The restriction recommended by the
commenters could result in the surveys spending increased time on the
water, which may result in greater overall exposure to sound for marine
mammals; thus the commenters have not demonstrated that such a
requirement would result in a net benefit. Furthermore, restricting the
applicant to begin operations only during daylight hours would have the
potential to result in lengthy shutdowns of the survey equipment, which
could result in the applicant failing to collect the data they have
determined is necessary and, subsequently, the need to conduct
additional surveys the following year. This would result in
significantly increased costs incurred by the applicant. Thus, the
restriction suggested by the commenters would not be practicable for
the applicant to implement. In consideration of the likely effects of
the activity on marine mammals absent mitigation, potential unintended
consequences of the measures as proposed by the commenters, and
practicability of the recommended measures for the applicant, NMFS has
determined that restricting operations as recommended is not warranted
or practicable in this case.
Comment 6: Based on the assertion that the 160 dB threshold for
behavioral harassment is not supported by best available scientific
information and grossly underestimates Level B take, the ENGOs
recommended that NMFS establish an EZ of 1,000 m around each vessel
conducting activities with noise levels that they assert could result
in injury or harassment to North Atlantic right whales, and a minimum
EZ of 500 m for all other large whale species and strategic stocks of
small cetaceans.
Response: NMFS disagrees with this recommendation and the assertion
that the 160 dB threshold for behavioral harassment is not supported by
best available scientific information and grossly underestimates take
by Level B harassment.
Regarding the 160-dB threshold, NMFS acknowledges that the 160-dB
rms step-function approach is simplistic, and that an approach
reflecting a more complex probabilistic function may more effectively
represent the known variation in responses at different levels due to
differences in the receivers, the context of the exposure, and other
factors. The commenters suggested that our use of the 160-dB threshold
implies that we do not recognize the science indicating that animals
may react in ways constituting behavioral harassment when exposed to
lower received levels (RL). However, we do recognize the potential for
Level B harassment at exposures to RLs below 160 dB rms, in addition to
the potential that animals exposed to RLs above 160 dB rms will not
respond in ways constituting behavioral harassment (e.g., Malme et al.,
1983, 1984, 1985, 1988; McCauley et al., 1998, 2000a, 2000b; Barkaszi
et al., 2012; Stone, 2015a; Gailey et al., 2016; Barkaszi and Kelly,
2018). These comments appear to evidence a misconception regarding the
concept of the 160-dB threshold. While it is correct that in practice
it works as a step-function, i.e., animals exposed to RLs above the
threshold are considered to be ``taken'' and those exposed to levels
below the threshold are not, it is in fact intended as a sort of mid-
point of likely behavioral responses (which are extremely complex
depending on many factors including species, noise source, individual
experience, and behavioral context). What this means is that,
conceptually, the function recognizes that some animals exposed to
levels below the threshold will in fact react in ways that are
appropriately considered take, while others that are exposed to levels
above the threshold will not. Use of the 160-dB threshold allows for a
simplistic quantitative estimate of take, while we can qualitatively
address the variation in responses across different RLs in our
discussion and analysis.
As behavioral responses to sound depend on the context in which an
animal receives the sound, including the animal's behavioral mode when
it hears sounds, prior experience, additional biological factors, and
other contextual factors, defining sound levels that disrupt behavioral
patterns is extremely difficult. Even experts have not previously been
able to suggest specific new criteria due to these difficulties (e.g.,
Southall et al. 2007; Gomez et al., 2016).
Regarding the shutdown zone recommendation, we note that the 500-m
EZ for North Atlantic right whales exceeds the modeled distance to the
largest 160-dB Level B harassment isopleth distance (141 m) by a factor
of more than three. Given that calculated Level B harassment isopleths
are likely conservative, and NMFS considers impacts from HRG survey
activities to be near de minimis, a 100-m shutdown for other marine
mammal species (including large whales and strategic stocks of small
cetaceans) is sufficiently protective to effect the least practicable
adverse impact on those species and stocks.
Comment 7: The ENGOs recommended that Mayflower must employ a
minimum of four protected species observers (PSOs) following a two-on,
two-off rotation, each responsible for scanning no more than 180[deg]
of the horizon during both daylight and nighttime hours. The commenters
also recommended that infrared equipment should be during daylight
hours to maximize the probability of detection of marine mammals.
Response: NMFS typically requires that a single PSO must be
stationed at the highest vantage point and engaged in general 360-
degree scanning during daylight hours. Although NMFS acknowledges that
the single PSO cannot reasonably maintain observation of the entire
360-degree area around the vessel, it is reasonable to assume that the
single PSO engaged in continual scanning of such a small area (i.e.,
500-m EZ, which is greater than the maximum 141-m harassment zone) will
be successful in detecting marine mammals that are available for
detection at the surface. The monitoring reports submitted to NMFS have
demonstrated that PSOs active only during daylight operations are able
to detect marine mammals and implement appropriate mitigation measures.
Nevertheless, as night vision technology has continued to improve, NMFS
has adapted its practice, and two PSOs are required to be on duty at
night. As the ENGOs noted, NMFS has included a requirement in the final
IHA that night-vision equipment (i.e., night-vision goggles with
thermal clip-ons and infrared/thermal imaging technology) must be
available for use. Under the issued IHA, survey operators are not
required to provide PSOs with infrared devices during the day but
observers are not prohibited from employing them. Given that use of
infrared devices for detecting marine mammals during the day has been
shown to be helpful under certain conditions, NMFS will consider
requiring them to be made accessible for daytime PSOs.
Comment 8: The ENGOs recommended that NMFS should require passive
acoustic monitoring (PAM) at all times, both day and night, to maximize
the probability of detection for North Atlantic right whales, and other
protected species and stocks.
Response: The foremost concern expressed by the ENGOs in making the
recommendation to require use of PAM is with regard to North Atlantic
right whales. However, the commenters do not explain why they expect
that PAM would be effective in detecting
[[Page 38038]]
vocalizing mysticetes. It is generally well-accepted fact that, even in
the absence of additional acoustic sources, using a towed passive
acoustic sensor to detect baleen whales (including right whales) is not
typically effective because the noise from the vessel, the flow noise,
and the cable noise are in the same frequency band and will mask the
vast majority of baleen whale calls. Vessels produce low-frequency
noise, primarily through propeller cavitation, with main energy in the
5-300 Hertz (Hz) frequency range. Source levels range from about 140 to
195 decibel (dB) re 1 [mu]Pa (micropascal) at 1 m (NRC, 2003;
Hildebrand, 2009), depending on factors such as ship type, load, and
speed, and ship hull and propeller design. Studies of vessel noise show
that it appears to increase background noise levels in the 71-224 Hz
range by 10-13 dB (Hatch et al., 2012; McKenna et al., 2012; Rolland et
al., 2012). PAM systems employ hydrophones towed in streamer cables
approximately 500 m behind a vessel. Noise from water flow around the
cables and from strumming of the cables themselves is also low-
frequency and typically masks signals in the same range. Experienced
PAM operators participating in a recent workshop (Thode et al., 2017)
emphasized that a PAM operation could easily report no acoustic
encounters, depending on species present, simply because background
noise levels rendered any acoustic detection impossible. The same
workshop report stated that a typical eight-element array towed 500 m
behind a vessel could be expected to detect delphinids, sperm whales,
and beaked whales at the required range, but not baleen whales, due to
expected background noise levels (including seismic noise, vessel
noise, and flow noise).
There are several additional reasons why we do not agree that use
of PAM is warranted for 24-hour HRG surveys. While NMFS agrees that PAM
can be an important tool for augmenting detection capabilities in
certain circumstances, its utility in further reducing impact during
HRG survey activities is limited. First, for this activity, the area
expected to be ensonified above the Level B harassment threshold is
relatively small (a maximum of 141 m)--this reflects the fact that, to
start with, the source level is comparatively low and the intensity of
any resulting impacts would be lower level and, further, it means that
inasmuch as PAM will only detect a portion of any animals exposed
within a zone, the overall probability of PAM detecting an animal in
the harassment zone is low--together these factors support the limited
value of PAM for use in reducing take with smaller zones. PAM is only
capable of detecting animals that are actively vocalizing, while many
marine mammal species vocalize infrequently or during certain
activities, which means that only a subset of the animals within the
range of the PAM would be detected (and potentially have reduced
impacts). Additionally, localization and range detection can be
challenging under certain scenarios. For example, odontocetes are fast
moving and often travel in large or dispersed groups which makes
localization difficult.
Given that the effects to marine mammals from the types of surveys
authorized in this IHA are expected to be limited to low level
behavioral harassment even in the absence of mitigation, the limited
additional benefit anticipated by adding this detection method
(especially for right whales and other low frequency cetaceans, species
for which PAM has limited efficacy), and the cost and impracticability
of implementing a full-time PAM program, we have determined the current
requirements for visual monitoring are sufficient to ensure the least
practicable adverse impact on the affected species or stocks and their
habitat.
Comment 9: The ENGOs recommended that NMFS should require Mayflower
to select sub-bottom profiling systems for survey activities, and
operate those systems at power settings that achieve the lowest
practicable source level for the objective.
Response: Wind energy developers selected the equipment necessary
during HRG surveys to achieve their objectives. As part of the analysis
for all HRG IHAs, NMFS evaluated the effects expected as a result of
use of this equipment, made the necessary findings, and imposed
mitigation requirements sufficient to achieve the least practicable
adverse impact on the affected species and stocks of marine mammals. It
is not within NMFS' purview to make judgments regarding what
constitutes the ``lowest practicable source level'' for an operator's
survey objectives.
Comment 10: The ENGOs recommended that NMFS require all offshore
wind energy related project vessels operating within or transiting to/
from survey areas, regardless of size, to observe a 10-knot speed
restriction during the entire survey period.
Response: NMFS does not concur with these measures. NMFS has
analyzed the potential for ship strike resulting from various HRG
activities and has determined that the mitigation measures specific to
ship strike avoidance are sufficient to avoid the potential for ship
strike. These include: A requirement that all vessel operators comply
with 10 knot (18.5 km/hour) or less speed restrictions in any
established DMA or SMA; a requirement that all vessel operators reduce
vessel speed to 10 knots (18.5 km/hour) or less when any large whale,
mother/calf pairs, pods, or large assemblages of non-delphinid
cetaceans are observed within 100 m of an underway vessel; a
requirement that all survey vessels maintain a separation distance of
500 m or greater from any sighted North Atlantic right whale; a
requirement that, if underway, vessels must steer a course away from
any sighted North Atlantic right whale at 10 knots or less until the
500 m minimum separation distance has been established; a requirement
that all vessels must maintain a minimum separation distance of 100 m
from sperm whales and all other baleen whales; and a requirement that
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). We have determined that
the ship strike avoidance measures are sufficient to ensure the least
practicable adverse impact on species or stocks and their habitat.
Furthermore, no documented vessel strikes have occurred for any marine
site characterization survey activities which were issued IHAs from
NMFS.
Comment 11: The ENGOs recommend that NMFS develop a robust and
effective near real-time monitoring and mitigation system for North
Atlantic right whales and other endangered and protected species that
will be more responsive to the ongoing dynamic species distributional
shifts resulting from climate change, as well as provide more
flexibility to developers during offshore wind energy development.
Response: NMFS is generally supportive of this concept. A network
of near real-time baleen whale monitoring devices are active or have
been tested in portions of New England and Canadian waters. These
systems employ various digital acoustic monitoring instruments which
have been placed on autonomous platforms including slocum gliders, wave
gliders, profiling floats and moored buoys. Systems that have proven to
be successful will likely see increased use as operational tools for
many whale monitoring and mitigation applications. The ENGOs cited the
[[Page 38039]]
NMFS publication ``Technical Memorandum NMFS-OPR-64: North Atlantic
Right Whale Monitoring and Surveillance: Report and Recommendations of
the National Marine Fisheries Service's Expert Working Group'' which is
available at: <a href="https://www.fisheries.noaa.gov/resource/document/north-atlantic-right-whale-monitoring-and-surveillance-report-and-recommendations">https://www.fisheries.noaa.gov/resource/document/north-atlantic-right-whale-monitoring-and-surveillance-report-and-recommendations</a>. This report summarizes a workshop NMFS convened to
address objectives related to monitoring North Atlantic right whales
and presents the Expert Working Group's recommendations for a
comprehensive monitoring strategy to guide future analyses and data
collection. Among the numerous recommendations found in the report, the
Expert Working Group encouraged the widespread deployment of auto-buoys
to provide near real-time detections of North Atlantic right whale
calls that visual survey teams can then respond to for collection of
identification photographs or biological samples.
Comment 12: The ENGOs state that NMFS must not issue renewal IHAs
since the process is contrary to statutory requirements.
Response: NMFS' IHA renewal process meets all statutory
requirements. In prior responses to comments about IHA Renewals (e.g.,
84 FR 52464; October 02, 2019 and 85 FR 53342, August 28, 2020), NMFS
has explained how the renewal process, as implemented, is consistent
with the statutory requirements contained in section 101(a)(5)(D) of
the MMPA, provides additional efficiencies beyond the use of
abbreviated notices, and, further, promotes NMFS' goals of improving
conservation of marine mammals and increasing efficiency in the MMPA
compliance process. Therefore, we intend to continue implementing the
renewal process.
The notice of the modified proposed IHA published in the Federal
Register on May 20, 2021 (86 FR 86 FR 27393) made clear that the agency
was seeking comment on the modified proposed IHA and the potential
issuance of a renewal for this project. Because any renewal is limited
to another year of identical or nearly identical activities in the same
location or the same activities that were not completed within the 1-
year period of the initial IHA, reviewers have the information needed
to effectively comment on both the immediate proposed IHA and a
possible 1-year renewal, should the IHA holder choose to request one in
the coming months.
While there would be additional documents submitted with a renewal
request, for a qualifying renewal these would be limited to
documentation that NMFS would make available and use to verify that the
activities are identical to those in the initial IHA, are nearly
identical such that the changes would have either no effect on impacts
to marine mammals or decrease those impacts, or are a subset of
activities already analyzed and authorized but not completed under the
initial IHA. NMFS would also need to confirm, among other things, that
the activities would occur in the same location; involve the same
species and stocks; provide for continuation of the same mitigation,
monitoring, and reporting requirements; and that no new information has
been received that would alter the prior analysis. The renewal request
would also contain a preliminary monitoring report, in order to verify
that effects from the activities do not indicate impacts of a scale or
nature not previously analyzed. The additional 15-day public comment
period provides the public an opportunity to review these few
documents, provide any additional pertinent information and comment on
whether they think the criteria for a renewal have been met. Between
the initial 30-day comment period on these same activities and the
additional 15 days, the total comment period for a renewal is 45 days.
Changes From the Modified Proposed IHA to Final IHA
There were no changes made between the modified proposed IHA and
the final IHA.
Description of Marine Mammals in the Area of the 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; <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and more general information about these species
(e.g., physical and behavioral descriptions) may be found on NMFS's
website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
Table 2 lists all species or stocks for which take is expected and
authorized for this action, and summarizes information related to the
population or stock, including regulatory status under the MMPA and ESA
and potential biological removal (PBR), where known. For taxonomy, NMFS
follows Committee on Taxonomy (2020). PBR is defined by the MMPA as the
maximum number of animals, not including natural mortalities, that may
be removed from a marine mammal stock while allowing that stock to
reach or maintain its optimum sustainable population (as described in
NMFS's SARs). While no mortality 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 Project 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's U.S. Atlantic SARs. All values presented in Table 2 are the most
recent available at the time of publication and are available in the
2019 Atlantic and Gulf of Mexico Marine Mammal SARs (Hayes et al.,
2020), available online at: <a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region">www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region</a> and
draft 2020 Atlantic and Gulf of Mexico Marine Mammal SARs available
online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports</a>.
[[Page 38040]]
Table 2--Marine Mammals Likely To Occur in the Project Area That May Be Affected by Mayflower's Planned Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
ESA/MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR \3\ Annual M/SI
\1\ abundance survey) \2\ \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenidae:
North Atlantic right whale..... Eubalaena glacialis... Western North Atlantic E/D; Y 412 (0; 408; 2018).... 0.89 18.6
Family Balaenopteridae (rorquals):
Humpback whale................. Megaptera novaeangliae Gulf of Maine......... -/-; Y 1,393 (0; 1,375; 2016) 22 58
Fin whale...................... Balaenoptera physalus. Western North Atlantic E/D; Y 6,820 (0.24; 5,573; 12 2.35
2016).
Sei whale...................... Balaenoptera borealis. Nova Scotia........... E/D; Y 6292 (1.02; 3,098; 6.2 1.2
2016).
Minke whale........................ Balaenoptera Canadian East Coast... -/-; N 21,968 (0.31; 17,002; 170 10.6
acutorostrata. 2016).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Physeteridae:
Sperm whale.................... Physeter macrocephalus NA.................... E; Y 4,349 (0.28;3,451; See 3.9 0
SAR).
Family Delphinidae:
Long-finned pilot whale........ Globicephala melas.... Western North Atlantic -/-; N 39,215 (0.3; 30,627; 306 21
See SAR).
Bottlenose dolphin............. Tursiops truncatus.... Western North Atlantic -/-; N 62,851 (0.213; 51,914; 519 28
Offshore. See SAR).
Common dolphin................. Delphinus delphis..... Western North Atlantic -/-; N 172,897 (0.21; 1,452 399
145,216; 2016).
Atlantic white-sided dolphin... Lagenorhynchus acutus. Western North Atlantic -/-; N 92,233 (0.71; 54,433; 544 26
See SAR).
Risso's dolphin................ Grampus griseus....... Western North Atlantic -/-; N 35,493 (0.19; 30,289; 303 54.3
See SAR).
Family Phocoenidae (porpoises):
Harbor porpoise................ Phocoena phocoena..... Gulf of Maine/Bay of -/-; N 95,543 (0.31; 74,034; 851 217
Fundy. 2016).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals):
Gray seal \4\.................. Halichoerus grypus.... Western North Atlantic -/-; N 27,131 (0.19; 23,158, 1,389 4,729
2016).
Harbor seal........................ Phoca vitulina........ Western North Atlantic -/-; N 75,834 (0.15; 66,884, 2,006 350
2012).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region/">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region/</a>. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable
\3\ Potential biological removal, defined by the MMPA as the maximum number of animals, not including natural mortalities, that may be removed from a
marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population size (OSP). Annual M/SI, found in NMFS' SARs,
represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial fisheries, subsistence hunting, ship
strike). Annual M/SI values often cannot be determined precisely and is in some cases presented as a minimum value.
\4\ NMFS stock abundance estimate applies to U.S. population only, actual stock abundance is approximately 451,431.
As indicated above, all 14 species (with 14 managed stocks) in
Table 2 temporally and spatially co-occur with the planned activity to
the degree that take is reasonably likely to occur, and NMFS has
authorized such take.
A description of the marine mammals for which take is likely to
occur may be found in the documents supporting Mayflower's previous IHA
covering Lease Area OCS-A 0521 and potential submarine cable routes (85
FR 45578; July 29, 2020), the same general geographic areas where
Mayflower has planned activities for this IHA. The most recent draft
SARs data has been included in Table 2.
Effects of Specified Activities on Marine Mammals and Their Habitat
The underwater noise from Mayflower's survey activities has the
potential to result in take of marine mammals by harassment in the
vicinity of the survey area. The Federal Register notice for the
proposed IHA (86 FR 11930; March 1, 2021) included a discussion of the
effects of anthropogenic noise on marine mammals and their habitat.
That information and analysis is incorporated by reference into this
final IHA determination and is not repeated here; please refer to the
notice of proposed IHA (86 FR 11930; March 1, 2021).
Estimated Take
This section provides an estimate of the number of incidental takes
authorized 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
[[Page 38041]]
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes would be by Level B harassment only in the form of
disruption of behavioral patterns for individual marine mammals
resulting from exposure to HRG sources. Based on the nature of the
activity and the anticipated effectiveness of the mitigation measures
(i.e., EZs and shutdown measures), discussed in detail below in the
Mitigation section, Level A harassment is neither anticipated nor
authorized.
As described previously, no mortality is anticipated or 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 basic calculation to provide an initial
prediction of takes, additional information that can qualitatively
inform take estimates is also sometimes available (e.g., previous
monitoring results or average group size). Below, we describe the
factors considered here in more detail and present the authorized take.
Acoustic Thresholds
NMFS recommends the use of acoustic thresholds that identify the
received level of underwater sound above which exposed marine mammals
would be reasonably expected to be behaviorally harassed (equated to
Level B harassment) or to incur permanent threshold shift (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 NMFS considers Level B
harassment when exposed to underwater anthropogenic noise above
received levels of 120 dB re 1 [mu]Pa (rms) for continuous (e.g.,
vibratory pile-driving, drilling) and above 160 dB re 1 [mu]Pa (rms)
for non-explosive impulsive (e.g., seismic airguns) or intermittent
(e.g., scientific sonar) sources. Mayflower's planned activity includes
the use of intermittent sources (geophysical survey equipment), and
therefore use of the 160 dB re 1 [mu]Pa (rms) threshold 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) (Technical Guidance, 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). Mayflower's planned activities that could
result in take by harassment include the use of impulsive and non-
impulsive sources.
Predicted distances to Level A harassment isopleths, which vary
based on marine mammal functional hearing groups were calculated. The
updated acoustic thresholds for impulsive and non-impulsive sounds
contained in the Technical Guidance (NMFS, 2018) were presented as dual
metric acoustic thresholds using both cumulative sound exposure level
(SEL<INF>cum</INF>) and peak sound pressure level metrics. As dual
metrics, NMFS considers onset of PTS (Level A harassment) to have
occurred when either one of the two metrics is exceeded (i.e., metric
resulting in the largest isopleth). The SEL<INF>cum</INF> metric
considers both level and duration of exposure, as well as auditory
weighting functions by marine mammal hearing group.
These thresholds are provided in Table 3 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:
<a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>.
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 (MF) Cetaceans........... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 218 dB; Cell 8: LE,PW,24h: 201 dB.
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 232 dB; Cell 10: LE,OW,24h: 219 dB.
LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
has a reference value of 1[micro]Pa2s. In this Table, thresholds are abbreviated to reflect American National
Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as incorporating
frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript ``flat'' is
being included to indicate peak sound pressure should be flat weighted or unweighted within the generalized
hearing range. The subscript associated with cumulative sound exposure level thresholds indicates the
designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and
that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could be
exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it
is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
[[Page 38042]]
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.
The planned survey activities would entail the use of HRG
equipment. The distance to the isopleth corresponding to the threshold
for Level B harassment was calculated for all HRG equipment with the
potential to result in harassment of marine mammals. NMFS has developed
methodology for determining the rms sound pressure level
(SPL<INF>rms</INF>) at the 160-dB isopleth for the purposes of
estimating take by Level B harassment resulting from exposure to HRG
survey equipment. This methodology incorporates frequency and some
directionality to refine estimated ensonified zones. Mayflower used
this methodology. For sources that operate with different beam widths,
the maximum beam width was used. The lowest frequency of the source was
used when calculating the absorption coefficient. The formulas used to
apply the methodology are described in detail in Appendix A of the IHA
application.
NMFS considers the data provided by Crocker and Fratantonio (2016)
to represent the best available information on source levels associated
with HRG equipment and therefore recommends that source levels provided
by Crocker and Fratantonio (2016) be incorporated in the method
described above to estimate isopleth distances to the Level B
harassment threshold. Table 1 shows the HRG equipment types that may be
used during the planned surveys and the sound levels associated with
those HRG equipment.
Table 4--Estimated Distances to Level A and Level B Harassment Thresholds for the Planned Survey Equipment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Distance (m) to Level A harassment threshold \1\ Distance to
-------------------------------------------------------------------------------- Level B
harassment
Representative system(s) threshold (m)
LFC MFC HFC PPW OPW ---------------
All marine
mammals
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sparker
--------------------------------------------------------------------------------------------------------------------------------------------------------
SIG ELC 820 @750 J...................................... 1 <1 \2\ 4 <1 <1 141
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sub-Bottom Profiler
--------------------------------------------------------------------------------------------------------------------------------------------------------
Teledyne Benthos Chirp III.............................. 2 <1 57 1 <1 66
--------------------------------------------------------------------------------------------------------------------------------------------------------
Boomer
--------------------------------------------------------------------------------------------------------------------------------------------------------
Applied Acoustics S-boom @700 J......................... <1 <1 \2\ 1 <1 <1 90
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Distances to the Level A harassment threshold based on the larger of the dual criteria (peak SPL and SELcum) are shown.
\2\ Peak SPL pressure level resulted in larger isopleth than SELcum.
NMFS has determined that the potential for take by Level A
harassment is so low as to be discountable and has not authorized take
by Level A harassment of any mammals. This determination is based on
the modeling of distances to Level A harassment thresholds which
resulted in small isopleths. This modeling was performed for all types
of HRG equipment planned for use with the potential to result in
harassment of marine mammals. Rather than repeat the description of the
model here, NMFS refers the reader to the notice of modified proposed
IHA published in the Federal Register (86 FR 27393; May 20, 2021). Note
that there is one species (harbor porpoise) within the high frequency
functional hearing group that may be impacted by the planned
activities. However, the largest modeled distance to the Level A
harassment threshold for the high frequency functional hearing group
was 57 m (Table 4) for the Chirp III. This is likely a conservative
assessment given that the JASCO model treats all devices as impulsive
and results in gross overestimates for non-impulsive devices. Level A
harassment would also be more likely to occur at close approach to the
sound source or as a result of longer duration exposure to the sound
source, and mitigation measures--including a 100 m EZ zone for harbor
porpoises--are expected to minimize the potential for close approach or
longer duration exposure to active HRG sources. In addition, harbor
porpoises are a notoriously shy species which is known to avoid
vessels. Harbor porpoises would also be expected to avoid a sound
source prior to that source reaching a level that would result in
injury (Level A harassment). Therefore, NMFS has determined that take
of harbor porpoises or any other animal is unlikely to occur.
The largest distance to the 160 dB SPL<INF>rms</INF> Level B
harassment threshold is expected to be 141 m from the sparkers. This
distance was used as described in this section to estimate the area of
water potentially exposed above the Level B harassment threshold by the
planned activities.
Up to 14,350 km of survey activity may occur from April through
November 2021, including turns between lines or occasional testing of
equipment while not collecting geophysical data. For the purposes of
calculating take, Mayflower's HRG survey activities have been split
into two different areas, (1) the lease area plus the deep-water
portion of the cable route, and (2) the shallow water portion of the
cable route including very shallow water sections of the cable route.
Within the Lease Area and deep-water portion of the cable route,
the vessel will conduct surveys at a speed of approximately 3 knots
(5.6 km/hr) during mostly 24-hr operations. Allowing for weather and
equipment downtime, the survey vessel is expected to collect
geophysical data over an average distance of 80 km per day. Using a 160
dB SPL<INF>rms</INF> threshold distance of 141 m, the total daily
[[Page 38043]]
ensonified area is estimated to be 282.8 km\2\ within the Lease Area
and deep-water portion of the cable route.
Along the shallow-water portion of the cable route, survey vessels
will also conduct surveys at a speed of approximately 3 knots (5.6 km/
hr) during either daylight only or 24-hour operations. Survey
operations in very shallow water will occur only during daylight hours.
Allowing for weather and equipment downtime, the survey vessels are
expected to cover an average distance of approximately 30-60 km per day
in shallow waters and only 15 km per day in very shallow waters.
Assuming daylight only operations and 30 km per day of surveys in
shallow waters results in slightly larger ensonified area estimates.
Distributing the 3,250 km of survey data to be collected in shallow
waters and the 4,100 km to be collected in very shallow waters across
the 7-month period of anticipated activity results in approximately
15.5 and 39 survey days per month in shallow and very-shallow waters,
respectively. Using a 160 dB SPL<INF>rms</INF> threshold distance of
141 m, the total daily ensonified area in shallow waters is estimated
to be 8.5 km\2\, and in very-shallow waters 4.3 km\2\. Combined, these
result in an average monthly ensonified area in the combined shallow
water survey areas of 299.5 km\2\.
Marine Mammal Occurrence
In this section NMFS provides the information about the presence,
density, or group dynamics of marine mammals that will inform the take
calculations. Note that Mayflower submitted a partial marine mammal
monitoring report under the existing IHA (85 FR 45578; July 39, 2020)
which included the first 90 days of survey work. A total of 415
individual identifiable marine mammals from six species were observed
within the predicted Level B harassment zone while an HRG source was
active. These observations included one humpback whale, two minke
whales, two sei whales, three bottlenose dolphins and 405 common
dolphins. There were also two unidentified seal observations. An
additional 24 unidentified dolphins and one unidentified whale were
observed inside the estimated Level B harassment zone but those
observations could not be identified to the species level. All
mitigation and monitoring requirements were followed and Mayflower did
not exceed authorized take limits for any species.
Density estimates for all species except North Atlantic right whale
within the deep and shallow portions of the survey areas were derived
from habitat-based density modeling results reported by Roberts et al.
(2016, 2017, 2018). Those data provide abundance estimates for species
or species guilds within 10 km x 10 km grid cells (100 km\2\) on a
monthly or annual basis, depending on the species. In order to select a
representative sample of grid cells in and near the survey areas, a 10-
km wide perimeter around the lease area and an 8-km wide perimeter
around the cable routes were created in GIS (ESRI 2017). The perimeters
were then used to select grid cells near the survey areas containing
the most recent monthly or annual estimates for each species in the
Roberts et al. (2016, 2017, 2018) data. The average monthly abundance
for each species in each survey area was calculated as the mean value
of the grid cells within each survey area in each month and then
converted to density (individuals/1 km\2\) by dividing by 100 km\2\
(Table 5, Table 6).
The estimated monthly densities of North Atlantic right whales were
based on updated model results from Roberts et al. (2020). These
updated data for North Atlantic right whales are provided as densities
(individuals/1 km\2\) within 5 km x 5 km grid cells (25 km\2\) on a
monthly basis. The same GIS process described above was used to select
the appropriate grid cells from each month and the monthly North
Atlantic right whales density in each survey area was calculated as the
mean value of the grid cells within each survey area as shown in Table
5 and Table 6.
The estimated monthly density of seals provided in Roberts et al.
(2018) includes all seal species present in the region as a single
guild. Mayflower did not separate this guild into the individual
species based on the proportion of sightings identified to each species
within the dataset because so few of the total sightings used in the
Roberts et al. (2018) analysis were actually identified to species
(Table 5, Table 6).
Marine mammal densities from Roberts et al. (2018) data in areas
immediately adjacent to the coast and within Nantucket Sound were used
when calculating potential takes from survey activities within
Narragansett Bay. This is a conservative approach since there have only
been a few reported sightings of marine mammal species, besides seals,
within Narragansett Bay (Raposa 2009).
For comparison purposes and to account for local variation not
captured by the predicted densities provided by Roberts et al. (2016,
2017, 2018, 2020), Protected Species Observers (PSOs) data from
Mayflower's 2020 HRG surveys were analyzed to assess the
appropriateness of the density-based take calculations. To do this, the
total number of individual marine mammals sighted by PSOs within 150 m
of a sound source (rounding up from the 141-m Level B harassment
distance) from April 19 through September 19, 2020, a period of 23
weeks, were summed by species or ``unidentified'' species group when
sightings were not classified to the species level. As a conservative
approach, all sightings were included in this calculation regardless of
whether the source was operating at the time. In order to include the
``unidentified'' individuals in the species-specific calculations, the
number of individuals in each unidentified species group (e.g.,
unidentified whale) was then added to the sums of the known species
within that group (e.g., humpback whale, fin whale, etc.) according to
the proportion of individuals within that group positively identified
to the species level. With individuals from ``unidentified'' species
sightings proportionally distributed among the species, Mayflower then
divided the total number of individuals of each species by the number
of survey weeks to calculate the average number of individuals of each
species sighted within 150 m of the sound sources per week during the
surveys. See section 6.4 in application for additional detail.
Mayflower currently plans for its survey activities to be concluded
in December 2021. If survey activities extend beyond December 2021, the
monthly densities for the marine mammals listed below may change,
potentially affecting take values. In that situation, Mayflower would
need to contact NMFS to determine a path forward to ensure that they
remain in compliance with the MMPA.
[[Page 38044]]
Table 5-Average Monthly Densities for Species That May Occur in the Lease Area and Along the Deep-Water Section of the Cable Route During the Planned
Survey Period
--------------------------------------------------------------------------------------------------------------------------------------------------------
Species Jun Jul Aug Sep Oct Nov Dec
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mysticetes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fin Whale.................................................... 0.0025 0.0025 0.0024 0.0020 0.0013 0.0011 0.0012
Humpback Whale............................................... 0.0012 0.0013 0.0009 0.0020 0.0015 0.0005 0.0006
Minke Whale.................................................. 0.0018 0.0007 0.0005 0.0005 0.0005 0.0003 0.0004
North Atlantic Right Whale................................... 0.0002 0.0000 0.0000 0.0000 0.0001 0.0005 0.0028
Sei Whale.................................................... 0.0002 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
--------------------------------------------------------------------------------------------------------------------------------------------------------
Odontocetes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Atlantic White-Sided Dolphin................................. 0.0449 0.0318 0.0180 0.0183 0.0234 0.0249 0.0317
Common Bottlenose Dolphin.................................... 0.0267 0.0585 0.0483 0.0546 0.0459 0.0223 0.0136
Harbor Porpoise.............................................. 0.0133 0.0088 0.0080 0.0067 0.0081 0.0267 0.0260
Pilot Whales................................................. 0.0046 0.0046 0.0046 0.0046 0.0046 0.0046 0.0046
Risso's Dolphin.............................................. 0.0001 0.0003 0.0006 0.0005 0.0002 0.0002 0.0004
Short-Beaked Common Dolphin.................................. 0.0410 0.0432 0.0747 0.1187 0.1280 0.0903 0.1563
Sperm Whale.................................................. 0.0001 0.0003 0.0003 0.0001 0.0001 0.0001 0.0000
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pinnipeds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Seals (Harbor and Gray)...................................... 0.0322 0.0078 0.0041 0.0054 0.0085 0.0091 0.0345
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 6--Average Monthly Densities for Species That May Occur Along the Shallow-Water Section of the Cable Route During the Planned Survey Period
--------------------------------------------------------------------------------------------------------------------------------------------------------
Species Jun Jul Aug Sep Oct Nov Dec
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mysticetes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fin Whale.................................................... 0.0003 0.0003 0.0003 0.0003 0.0002 0.0001 0.0001
Humpback Whale............................................... 0.0001 0.0001 0.0000 0.0001 0.0002 0.0001 0.0017
Minke Whale.................................................. 0.0002 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
North Atlantic Right Whale *................................. 0.0000 0.0000 0.0000 0.0000 0.0000 0.0001 0.0005
Sei Whale *.................................................. 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
--------------------------------------------------------------------------------------------------------------------------------------------------------
Odontocetes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Atlantic White-Sided Dolphin................................. 0.0010 0.0006 0.0005 0.0008 0.0014 0.0011 0.0006
Common Bottlenose Dolphin.................................... 0.2308 0.4199 0.3211 0.3077 0.1564 0.0813 0.0174
Harbor Porpoise.............................................. 0.0048 0.0023 0.0037 0.0036 0.0003 0.0214 0.0253
Pilot Whales................................................. 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Risso's Dolphin.............................................. 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
Short-Beaked Common Dolphin.................................. 0.0003 0.0002 0.0006 0.0009 0.0008 0.0010 0.0006
Sperm Whale.................................................. 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pinnipeds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Seal (Harbor and Gray)....................................... 0.2496 0.0281 0.0120 0.0245 0.0826 0.5456 1.3589
--------------------------------------------------------------------------------------------------------------------------------------------------------
Take Calculation and Estimation
Here NMFS describes how the information provided above is brought
together to produce a quantitative take estimate.
The potential numbers of takes by Level B harassment were
calculated by multiplying the monthly density for each species in each
survey area shown in Table 5 and Table 6 by the respective monthly
ensonified area within each survey area. The results are shown in the
``Calculated Take'' columns of Table 7. The survey area estimates were
then summed to produce the ``Total Density-based Calculated Take'' and
then rounded up to arrive at the number of ``Density-based Takes'' for
each species (Table 7).
To account for potential local variation in animal presence
compared to the predicted densities, the average weekly number of
individuals for each species observed within 150 m of the HRG survey
sound sources in 2020, regardless of their operational status at the
time were multiplied by the anticipated 32-week survey period in 2021.
These results are shown in the ``Sightings-based Takes'' column of
Table 7. The larger of the take estimates from the density-based and
sightings-based methods are shown in the ``Take'' column, except as
noted below.
Based on density and sightings data for the modified Project Area,
Mayflower modified its take authorization request and NMFS concurred
with its modification. Accordingly, NMFS has authorized the following
take reductions by Level B harassment as part of the issued IHA: 37 to
33 humpback whale takes; 15 to 14 minke whale takes; 85 to 57 Atlantic
white-sided dolphin takes; 2,153 to 1,969 common dolphin takes; 61 to
46 harbor porpoise takes; and 989 to 718 seal takes. The number of
authorized takes by Level B harassment for bottlenose dolphins has been
increased from 483 to 536.
[[Page 38045]]
The differences in requested take for four species (Atlantic white-
sided dolphin, common bottlenose dolphin, harbor porpoise, and seals)
resulted from a combination of different monthly densities as well as a
different monthly ensonified area being applied to those densities. The
same calculations were performed for all species, so the relative
changes in the requested take for these species was driven by the
amount of change in monthly densities for each species. The densities
changed between applications for two reasons, (1) the survey area
location was changed to include the alternative cable route and (2) the
months in which the activity will occur were shifted later in the year,
from April-November to June-December. The various combinations of
changes to these factors resulted in different relative changes to the
requested takes for these four species.
For the other three species (i.e., humpback whale, minke whale,
common dolphin) take calculated based on Roberts et al. densities was
considerably lower than observed numbers of animals during the 2020
surveys. Therefore, the numbers of observations per week were
considered more representative of the area densities. For humpback
whale, the requested take in the original proposed IHA was based on the
average weekly sightings rate from 2020 PSO observations (1.04 humpback
whales/week). The reduction in the authorized take is a result of the
shortened overall length of the activity from 35 weeks to 32 weeks. For
minke whale, the average weekly sightings rate from 2020 PSO
observations (0.43 minke whales/week) reduced authorized take due to
shortened overall length of the activity (from 35 weeks to 32 weeks).
The same reduction in authorized take of common dolphin was similarly
based on the average weekly sightings rate from 2020 PSO observations
(61.52 common dolphins/week) and the decreased overall length of the
activity. The reduction in the requested take is a result of the
shortened overall length of the activity (from 35 weeks to 32 weeks).
Using the best available density data (Roberts et al. 2016, 2017,
2018, 2020), Mayflower requested and NMFS has authorized 57 takes of
white-sided dolphin, 536 takes of bottlenose dolphin and 46 harbor
porpoise takes by Level B harassment. For six species, humpback whale,
North Atlantic right whale, sei whale, pilot whales, Risso's dolphin,
and sperm whale the authorized take column reflects a rounding up of
three times the mean group size calculated from survey data in this
region (Kraus et al. 2016; Palka et al. 2017). Three times the group
size was used rather than a single group size to account for more than
one chance encounter with these species during the surveys.
NFMS concurred with this assessment and, therefore, has authorized
take by Level B harassment of 9 North Atlantic right whales, 6 fin
whales, 6 sei whales, 27 pilot whales, 18 Risso's dolphins and 6 sperm
whales. The authorized take numbers for these species remains unchanged
from the original proposed IHA.
The authorized number of takes by Level B harassment as a
percentage of the ``best available'' abundance estimates provided in
the most recent NMFS draft Stock Assessment Reports (Hayes et al. 2020)
are also provided in Table 7. For the seal guild, the estimated
abundance for both gray and harbor seals was summed in Table 7.
Mayflower requested and NMFS has authorized 718 incidental takes of
harbor and gray seal by Level B harassment.
Bottlenose dolphins encountered in the survey area would likely
belong to the Western North Atlantic Offshore Stock (Hayes et al.
2020). However, it is possible that a few animals encountered during
the surveys could be from the North Atlantic Northern Migratory Coastal
Stock, but they generally do not range farther north than New Jersey.
Also, based on the distributions described in Hayes et al. (2020),
pilot whale sightings in the survey area would most likely be long-
finned pilot whales, although short-finned pilot whales could be
encountered in the survey area during the summer months.
For North Atlantic right whales, the implementation of a 500 m EZ
means that the likelihood of an exposure to received sound levels
greater than 160 dB SPL<INF>rms</INF> is very low. In addition, most of
the survey activity will take place during the time of year when North
Atlantic right whales are unlikely to be present in this region.
Nonetheless, it is possible that North Atlantic right whales could
occur within 500 m of the vessel without first being detected PSO, so
Mayflower requested and NMFS has authorized take consistent with other
species (i.e. three times average group size).
Table 7--Number of Level B Harassment Takes Authorized by NMFS and Percentages of Each Stock Abundance
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Lease area + Percent of
deep water Shallow water Total density- Density based Sightings Authorized Abundance stock
cable cable based takes takes based takes takes abundance
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Mysticetes
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Fin Whale....................................................... 3.7 0.5 4.1 5 1 6 3,006 0.2
Humpback Whale.................................................. 2.2 0.7 2.9 3 33 33 1,396 2.4
Minke Whale..................................................... 1.3 0.1 1.5 2 14 14 2,591 0.5
North Atlantic Right Whale...................................... 1.0 0.2 1.2 2 0 9 368 2.4
Sei Whale....................................................... 0.1 0.0 0.1 1 0 6 28 21.4
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Odontocetes
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Atlantic White-Sided Dolphin.................................... 54.6 1.8 56.4 57 0 57 31,912 0.2
Common Bottlenose Dolphin....................................... 76.3 459.6 536.0 536 59 536 62,851 0.9
Harbor Porpoise................................................. 27.6 18.4 46.0 46 0 46 75,079 0.1
Pilot Whales.................................................... 9.2 0.0 9.2 10 17 27 68,139 0.0
Risso's Dolphin................................................. 0.7 0.0 0.7 1 0 18 35,493 0.1
Short-Beaked Common Dolphin..................................... 184.5 1.3 185.8 186 1,969 1,969 80,227 2.5
Sperm Whale..................................................... 0.3 0.0 0.3 1 0 6 4,349 0.1
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 38046]]
Pinnipeds
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Seals (Harbor and Gray)......................................... 28.7 689.2 718.0 718 141 718 102,965 0.7
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
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 the
activity, and other means of effecting the least practicable impact on
the species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of the 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 the
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, NMFS
carefully considers two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat.
This considers the nature of the potential adverse impact being
mitigated (likelihood, scope, range). It further considers the
likelihood that the measure will be effective if implemented
(probability of accomplishing the mitigating result if implemented as
planned), the likelihood of effective implementation (probability
implemented as planned), and;
(2) The practicability of the measures for applicant
implementation, which may consider such things as cost, and impact on
operations.
Marine Mammal Exclusion Zones and Harassment Zones
NMFS is requiring Mayflower to implement the following mitigation
measures during Mayflower's planned marine site characterization
surveys.
Marine mammal EZs would be established around the HRG survey
equipment and monitored by protected species observers (PSO) during HRG
surveys as follows:
<bullet> A 500-m EZ would be required for North Atlantic right
whales during use of all acoustic sources; and
<bullet> 100 m EZ for all marine mammals, with certain exceptions
specified below, during operation of impulsive acoustic sources (boomer
and/or sparker).
If a marine mammal is detected approaching or entering the EZs
during the HRG survey, the vessel operator would adhere to the shutdown
procedures described below to minimize noise impacts on the animals.
These stated requirements will be included in the site-specific
training to be provided to the survey team.
Pre-Clearance of the Exclusion Zones
Mayflower will implement a 30-minute pre-clearance period of the
EZs prior to the initiation of ramp-up of HRG equipment. During this
period, the EZ will be monitored by the PSOs, using the appropriate
visual technology. Ramp-up may not be initiated if any marine mammal(s)
is within its respective EZ. If a marine mammal is observed within an
EZ during the pre-clearance period, ramp-up may not begin until the
animal(s) has been observed exiting its respective EZ or until an
additional time period has elapsed with no further sighting (i.e., 15
minutes for small odontocetes and seals, and 30 minutes for all other
species).
Ramp-Up of Survey Equipment
When technically feasible, a ramp-up procedure will be used for HRG
survey equipment capable of adjusting energy levels at the start or
restart of survey activities. The ramp-up procedure will be used at the
beginning of HRG survey activities in order to provide additional
protection to marine mammals near the Project Area by allowing them to
vacate the area prior to the commencement of survey equipment operation
at full power.
A ramp-up will begin with the powering up of the smallest acoustic
HRG equipment at its lowest practical power output appropriate for the
survey. When technically feasible, the power will then be gradually
turned up and other acoustic sources would be added.
Ramp-up activities will be delayed if a marine mammal(s) enters its
respective EZ. Ramp-up will continue if the animal has been observed
exiting its respective EZ or until an additional time period has
elapsed with no further sighting (i.e, 15 minutes for small odontocetes
and seals and 30 minutes for all other species).
Activation of survey equipment through ramp-up procedures may not
occur when visual observation of the pre-clearance zone is not expected
to be effective (i.e., during inclement conditions such as heavy rain
or fog).
Shutdown Procedures
An immediate shutdown of the impulsive HRG survey equipment is
required if a marine mammal is sighted entering or within its
respective EZ. The vessel operator must comply immediately with any
call for shutdown by the Lead PSO. Any disagreement between the Lead
PSO and vessel operator should be discussed only after shutdown has
occurred. Subsequent restart of the survey equipment can be initiated
if the animal has been observed exiting its respective EZ or until an
additional time period has elapsed (i.e., 30 minutes for all other
species).
If a species for which authorization has not been granted, or, a
species for which authorization has been granted but the authorized
number of takes have been met, approaches or is observed within the
Level B harassment zone (48 m, non-impulsive; 141 m impulsive),
shutdown will occur.
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 ramp-up if PSOs have maintained constant
observation and no detections of any marine mammal have occurred within
the respective EZs. If the acoustic source is shut down for a period
longer than 30 minutes and PSOs have maintained constant observation,
then pre-clearance and ramp-up procedures will be initiated as
described in the previous section.
[[Page 38047]]
The shutdown requirement would be waived for small delphinids of
the following genera: Delphinus, Lagenorhynchus, Stenella, and Tursiops
and seals. Specifically, if a delphinid from the specified genera or a
pinniped is visually detected approaching the vessel (i.e., to bow
ride) or towed equipment, shutdown is not required. Furthermore, if
there is uncertainty regarding identification of a marine mammal
species (i.e., whether the observed marine mammal(s) belongs to one of
the delphinid genera for which shutdown is waived), PSOs must use best
professional judgement in making the decision to call for a shutdown.
Additionally, shutdown is required if a delphinid or pinniped detected
in the EZ and belongs to a genus other than those specified.
Vessel Strike Avoidance
Mayflower will ensure that vessel operators and crew maintain a
vigilant watch for cetaceans and pinnipeds and slow down or stop their
vessels to avoid striking these species. Survey vessel crew members
responsible for navigation duties will receive site-specific training
on marine mammals sighting/reporting and vessel strike avoidance
measures. Vessel strike avoidance measures would include the following,
except under circumstances when complying with these requirements would
put the safety of the vessel or crew at risk:
<bullet> Vessel operators and crews must maintain a vigilant watch
for all protected species and slow down, stop their vessel, or alter
course, as appropriate and regardless of vessel size, to avoid striking
any protected species. A visual observer aboard the vessel must monitor
a vessel strike avoidance zone based on the appropriate separation
distance around the vessel (distances stated below). Visual observers
monitoring the vessel strike avoidance zone may be third-party
observers (i.e., PSOs) or crew members, but crew members responsible
for these duties must be provided sufficient training to (1)
distinguish protected species from other phenomena and (2) broadly to
identify a marine mammal as a right whale, other whale (defined in this
context as sperm whales or baleen whales other than right whales), or
other marine mammal.
<bullet> 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 including SMAs and DMAs when
in effect;
<bullet> All vessels greater than or equal to 19.8 m in overall
length operating from November 1 through April 30 will operate at
speeds of 10 knots or less while transiting to and from Project Area;
<bullet> All vessels must reduce their speed to 10 knots or less
when mother/calf pairs, pods, or large assemblages of cetaceans are
observed near a vessel.
<bullet> 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.
<bullet> All vessels must maintain a minimum separation distance of
100 m from sperm whales and all other baleen whales.
<bullet> 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).
<bullet> 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.
<bullet> 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.
<bullet> Members of the monitoring team will consult NMFS North
Atlantic right whale reporting system and Whale Alert, as able, for the
presence of North Atlantic right whales throughout survey operations,
and for the establishment of a DMA. If NMFS should establish a DMA in
the Lease Areas during the survey, the vessels will abide by speed
restrictions in the DMA.
Project-specific training will be conducted for all vessel crew
prior to the start of a survey and during any changes in crew such that
all survey personnel are fully aware and understand the mitigation,
monitoring, and reporting requirements. Prior to implementation with
vessel crews, the training program will be provided to NMFS for review
and approval. Confirmation of the training and understanding of the
requirements will be documented on a training course log sheet. Signing
the log sheet will certify that the crew member understands and will
comply with the necessary requirements throughout the survey
activities.
Based on our evaluation of the applicant's proposed measures, as
well as other measures considered by NMFS, we have determined that the
required mitigation measures provide the means of effecting the least
practicable impact on marine mammal species or stocks and their
habitat, paying particular attention to rookeries, mating grounds, and
areas of similar significance.
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
planned 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:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density).
<bullet> 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).
<bullet> Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or
[[Page 38048]]
cumulative impacts from multiple stressors.
<bullet> How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks.
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat).
<bullet> Mitigation and monitoring effectiveness.
Monitoring Measures
Visual monitoring will be performed by qualified, NMFS-approved
PSOs, the resumes of whom will be provided to NMFS for review and
approval prior to the start of survey activities. Mayflower would
employ independent, dedicated, trained PSOs, meaning that the PSOs must
(1) be employed by a third-party observer provider, (2) have no tasks
other than to conduct observational effort, collect data, and
communicate with and instruct relevant vessel crew with regard to the
presence of marine mammals and mitigation requirements (including brief
alerts regarding maritime hazards), and (3) have successfully completed
an approved PSO training course appropriate for their designated task.
On a case-by-case basis, non-independent observers may be approved by
NMFS for limited, specific duties in support of approved, independent
PSOs on smaller vessels with limited crew capacity operating in
nearshore waters.
The PSOs will be responsible for monitoring the waters surrounding
each survey vessel to the farthest extent permitted by sighting
conditions, including EZs, during all HRG survey operations. PSOs will
visually monitor and identify marine mammals, including those
approaching or entering the established EZs during survey activities.
It will be the responsibility of the Lead PSO on duty to communicate
the presence of marine mammals as well as to communicate the action(s)
that are necessary to ensure mitigation and monitoring requirements are
implemented as appropriate.
During all HRG survey operations (e.g., any day on which use of an
HRG source is planned to occur), a minimum of one PSO must be on duty
during daylight operations on each survey vessel, conducting visual
observations at all times on all active survey vessels during daylight
hours (i.e., from 30 minutes prior to sunrise through 30 minutes
following sunset). Two PSOs will be on watch during nighttime
operations. The PSO(s) would ensure 360[deg] visual coverage around the
vessel from the most appropriate observation posts and would conduct
visual observations using binoculars and/or night vision goggles and
the naked eye while free from distractions and in a consistent,
systematic, and diligent manner. PSOs may be on watch for a maximum of
four consecutive hours followed by a break of at least two hours
between watches and may conduct a maximum of 12 hours of observation
per 24-hour period. In cases where multiple vessels are surveying
concurrently, any observations of marine mammals would be communicated
to PSOs on all nearby survey vessels.
Vessels conducting HRG survey activities in very-shallow waters
using shallow-draft vessels are very limited in the number of personnel
that can be onboard. In such cases, one visual PSO will be onboard and
the vessel captain (or crew member on watch) will conduct observations
when the PSO is on required breaks. All vessel crew conducting PSO
watches will receive training in monitoring and mitigation requirements
and species identification necessary to reliably carry out the
mitigation requirements. Given the small size of these vessels, the PSO
would effectively remain available to confirm sightings and any related
mitigation measures while on break.
PSOs must be equipped with binoculars and have the ability to
estimate distance and bearing to detect marine mammals, particularly in
proximity to EZs. Reticulated binoculars must also be available to PSOs
for use as appropriate based on conditions and visibility to support
the sighting and monitoring of marine mammals. During nighttime
operations, night-vision goggles with thermal clip-ons and infrared
technology would be used. Position data would be recorded using hand-
held or vessel GPS units for each sighting.
During good conditions (e.g., daylight hours; Beaufort sea state
(BSS) 3 or less), to the maximum extent practicable, PSOs will also
conduct observations when the acoustic source is not operating for
comparison of sighting rates and behavior with and without use of the
active acoustic sources. Any observations of marine mammals by crew
members aboard any vessel associated with the survey will be relayed to
the PSO team.
Data on all PSO observations will be recorded based on standard PSO
collection requirements. This will include dates, times, and locations
of survey operations; dates and times of observations, location and
weather; details of marine mammal sightings (e.g., species, numbers,
behavior); and details of any observed marine mammal behavior that
occurs (e.g., noted behavioral disturbances).
Reporting Measures
Within 90 days after completion of survey activities or expiration
of this IHA, whichever comes sooner, a final technical report will be
provided to NMFS that fully documents the methods and monitoring
protocols, summarizes the data recorded during monitoring, summarizes
the number of marine mammals observed during survey activities (by
species, when known), summarizes the mitigation actions taken during
surveys (including what type of mitigation and the species and number
of animals that prompted the mitigation action, when known), and
provides an interpretation of the results and effectiveness of all
mitigation and monitoring. Any recommendations made by NMFS must be
addressed in the final report prior to acceptance by NMFS. All draft
and final marine mammal and acoustic monitoring reports must be
submitted to <a href="/cdn-cgi/l/email-protection#8adad8a4c3dedaa4c7e5e4e3fee5f8e3e4edd8effae5f8fef9cae4e5ebeba4ede5fc"><span class="__cf_email__" data-cfemail="f4a4a6dabda0a4dab99b9a9d809b869d9a93a691849b868087b49a9b9595da939b82">[email protected]</span></a>. The report must
contain, at minimum, the following:
<bullet> PSO names and affiliations;
<bullet> Dates of departures and returns to port with port name;
<bullet> Dates and times (Greenwich Mean Time) of survey effort and
times corresponding with PSO effort;
<bullet> Vessel location (latitude/longitude) when survey effort
begins and ends; vessel location at beginning and end of visual PSO
duty shifts;
<bullet> Vessel heading and speed at beginning and end of visual
PSO duty shifts and upon any line change;
<bullet> 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;
<bullet> 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); and
<bullet> Survey activity information, such as type of survey
equipment in operation, acoustic source power output while in
operation, and any other notes of significance (i.e., pre-clearance
survey, ramp-up, shutdown, end of operations, etc.).
[[Page 38049]]
If a marine mammal is sighted, the following information should be
recorded:
<bullet> Watch status (sighting made by PSO on/off effort,
opportunistic, crew, alternate vessel/platform);
<bullet> PSO who sighted the animal;
<bullet> Time of sighting;
<bullet> Vessel location at time of sighting;
<bullet> Water depth;
<bullet> Direction of vessel's travel (compass direction);
<bullet> Direction of animal's travel relative to the vessel;
<bullet> Pace of the animal;
<bullet> Estimated distance to the animal and its heading relative
to vessel at initial sighting;
<bullet> 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;
<bullet> Estimated number of animals (high/low/best);
<bullet> Estimated number of animals by cohort (adults, yearlings,
juveniles, calves, group composition, etc.);
<bullet> 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);
<bullet> 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);
<bullet> Animal's closest point of approach and/or closest distance
from the center point of the acoustic source;
<bullet> Platform activity at time of sighting (e.g., deploying,
recovering, testing, data acquisition, other); and
<bullet> 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.
If a North Atlantic right whale is observed at any time by PSOs or
personnel on any project vessels, during surveys or during vessel
transit, Mayflower must immediately report sighting information to the
NMFS North Atlantic Right Whale Sighting Advisory System: (866) 755-
6622. North Atlantic right whale sightings in any location may also be
reported to the U.S. Coast Guard via channel 16.
In the event that Mayflower personnel discover an injured or dead
marine mammal, Mayflower would report the incident to the NMFS Office
of Protected Resources (OPR) and the NMFS New England/Mid-Atlantic
Stranding Coordinator as soon as feasible. The report would include the
following information:
<bullet> Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
<bullet> Species identification (if known) or description of the
animal(s) involved;
<bullet> Condition of the animal(s) (including carcass condition if
the animal is dead);
<bullet> Observed behaviors of the animal(s), if alive;
<bullet> If available, photographs or video footage of the
animal(s); and
<bullet> General circumstances under which the animal was
discovered.
In the unanticipated event of a ship strike of a marine mammal by
any vessel involved in the activities covered by the IHA, Mayflower
would report the incident to the NMFS OPR and the NMFS New England/Mid-
Atlantic Stranding Coordinator as soon as feasible. The report would
include the following information:
<bullet> Time, date, and location (latitude/longitude) of the
incident;
<bullet> Species identification (if known) or description of the
animal(s) involved;
<bullet> Vessel's speed during and leading up to the incident;
<bullet> Vessel's course/heading and what operations were being
conducted (if applicable);
<bullet> Status of all sound sources in use;
<bullet> Description of avoidance measures/requirements that were
in place at the time of the strike and what additional measures were
taken, if any, to avoid strike;
<bullet> Environmental conditions (e.g., wind speed and direction,
Beaufort sea state, cloud cover, visibility) immediately preceding the
strike;
<bullet> Estimated size and length of animal that was struck;
<bullet> Description of the behavior of the marine mammal
immediately preceding and following the strike;
<bullet> If available, description of the presence and behavior of
any other marine mammals immediately preceding the strike;
<bullet> Estimated fate of the animal (e.g., dead, injured but
alive, injured and moving, blood or tissue observed in the water,
status unknown, disappeared); and
<bullet> To the extent practicable, photographs or video footage of
the animal(s).
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any responses (e.g., intensity, duration), the context
of any responses (e.g., critical reproductive time or location,
migration), as well as effects on habitat, and the likely effectiveness
of the mitigation. NMFS also assess the number, intensity, and context
of estimated takes by evaluating this information relative to
population status. Consistent with the 1989 preamble for NMFS's
implementing regulations (54 FR 40338; September 29, 1989), the impacts
from other past and ongoing anthropogenic activities are incorporated
into this analysis via their impacts on the environmental baseline
(e.g., as reflected in the regulatory status of the species, population
size and growth rate where known, ongoing sources of human-caused
mortality, or ambient noise levels).
To avoid repetition, our analysis applies to all the species listed
in Table 7 given that NMFS expects the anticipated effects of the
planned survey to be similar in nature. Where there are meaningful
differences between species or stocks--as in the case of the North
Atlantic right whale--they are included as separate subsections below.
NMFS does not anticipate that serious injury or mortality would
occur as a result from HRG surveys, even in the absence of mitigation,
and no serious injury or mortality is authorized. As discussed in the
Potential Effects of Specified Activity on Marine Mammals and their
Habitat section in the initial notice of proposed IHA (86 FR 11930;
March 1, 2021), non-auditory physical effects and vessel strike are not
expected to occur. NMFS expects that all potential takes would be in
the form of short-term Level B harassment behavioral harassment in the
form of temporary avoidance of the area or decreased foraging (if such
activity was occurring), reactions that are considered to be of low
severity and with no lasting biological consequences (e.g., Southall et
al., 2007). Even repeated Level B harassment of some small subset of an
overall stock is unlikely to result in any significant realized
decrease in viability
[[Page 38050]]
for the affected individuals, and thus would not result in any adverse
impact to the stock as a whole. As described above, Level A harassment
is not expected to occur given the nature of the operations, the
estimated size of the Level A harassment zones, and the required
shutdown zones for certain activities--and is not authorized. The
potential effects associated with the addition of the new export cable
route extending through Narragansett Bay are similar to those described
in the initial notice of proposed IHA (86 FR 11930; March 1, 2021).
In addition to being temporary, the maximum expected harassment
zone for the modified proposed IHA is identical to that in the initial
proposed IHA with a distance of 141 m per vessel. Therefore, the
ensonified area surrounding each vessel is also identical, and
relatively small, compared to the overall distribution of the animals
in the area and their use of the habitat. Feeding behavior is not
likely to be significantly impacted as prey species are mobile and are
broadly distributed throughout the modified Project Area; therefore,
marine mammals that may be temporarily displaced during survey
activities are expected to be able to resume foraging once they have
moved away from areas with disturbing levels of underwater noise.
Similar to the initial proposed IHA, given the temporary nature of the
disturbance and availability of similar habitat and resources in the
surrounding area, the impacts to marine mammals and the food sources
that they utilize are not expected to cause significant or long-term
consequences for individual marine mammals or their populations in the
issued IHA.
Furthermore, the Project Area is located approximately 50 miles
west of feeding BIAs for North Atlantic right whales (February-April)
and sei whales (May-November) and approximately 40 west of feeding BIAs
for humpback whales (March-December) and fin whales (March-October).
These were discussed in the previous IHA (85 FR 45578; July 29, 2020)
issued for this area. Additionally, the new Narragansett Bay cable
route corridor is located just to the north of another fin whale BIA
(March-October) south of Martha's Vineyard. Even if whales are feeding
outside of the identified feeding BIAs, they are extensive and
sufficiently large (705 km\2\ and 3,149 km\2\ for North Atlantic right
whales; 47,701 km\2\ for humpback whales; 2,933 km\2\ for fin whales;
and 56,609 km\2\ for sei whales), and the acoustic footprint of the
planned survey is sufficiently small, such that feeding opportunities
for these whales would not be reduced appreciably. Therefore, under the
issued IHA, NMFS does not expect impacts to whales within feeding BIAs
to affect the fitness of any large whales. Furthermore, NMFS does not
anticipate impacts from the planned survey that would impact the
fitness of any individual marine mammals, much less annual rates of
recruitment.
There are no rookeries, mating or calving grounds known to be
biologically important to marine mammals within the Project Area.
Furthermore, there is no designated critical habitat for any ESA-listed
marine mammals in the Project Area.
North Atlantic Right Whales
The status of the North Atlantic right whale population is of
heightened concern and, therefore, merits additional analysis. As noted
previously, elevated North Atlantic right whale mortalities began in
June 2017 and there is an active UME. Overall, our findings support
human interactions, specifically vessel strikes and entanglements, as
the cause of death for the majority of North Atlantic right whales. In
addition to the right whale feeding BIA located west of the planned
Project Area noted above, the Project Area overlaps a migratory
corridor BIA for North Atlantic right whales (effective March-April and
November-December) that extends from Massachusetts to Florida
(LeBrecque et al., 2015). Off the coast of Massachusetts, this
migratory BIA extends from the coast to beyond the shelf break. Due to
the fact that that the planned survey activities are temporary and the
spatial extent of sound produced by the survey would be very small
relative to the spatial extent of the available migratory habitat in
the BIA, right whale migration is not expected to be impacted by the
planned survey. Given the relatively small size of the ensonified area,
it is unlikely that prey availability would be adversely affected by
HRG survey operations. Required vessel strike avoidance measures will
also decrease risk of ship strike during migration; no ship strike is
expected to occur during Mayflower's planned activities. Additionally,
only very limited take by Level B harassment of North Atlantic right
whales has been requested by Mayflower and authorized by NMFS as HRG
survey operations are required to maintain a 500-m EZ and shutdown if a
North Atlantic right whale is sighted at or within the EZ. The 500-m
shutdown zone for North Atlantic right whales is conservative,
considering the Level B harassment isopleth for the most impactful
acoustic source (i.e., GeoMarine Geo-Source 400 tip sparker) is
estimated to be 141 m, and thereby minimizes the potential for
behavioral harassment of this species. As noted previously, Level A
harassment is not expected due to the small PTS zones associated with
HRG equipment types planned use.
As described previously, North Atlantic right whale presence is
increasingly variable in identified core habitats, including the
recently identified foraging area south of Martha's Vineyard and
Nantucket islands where both visual and acoustic detections of North
Atlantic right whales indicate a nearly year-round presence (Oleson et
al., 2020). However, prey for North Atlantic right whales are mobile
and broadly distributed throughout the Project Area; therefore, North
Atlantic right whales are expected to be able to resume foraging once
they have moved away from any areas with disturbing levels of
underwater noise. In addition, there are no North Atlantic right whale
mating or calving areas within the Project Area.
Given the information above, NMFS does not anticipate North
Atlantic right whales takes that would result from Mayflower's planned
activities would impact the reproduction or survival of any individual
North Atlantic right whales, much less annual rates of recruitment or
survival. Thus, any takes that occur under the issued IHA would not
result in population level impacts for the species.
Other Marine Mammal Species With Active UMEs
As noted in the previous IHA (85 FR 45578; July 29, 2020) there are
several active UMEs occurring in the vicinity of Mayflower's Project
Area. Elevated humpback whale mortalities have occurred along the
Atlantic coast from Maine through Florida since January 2016. Of the
cases examined, approximately half had evidence of human interaction
(ship strike or entanglement). The UME does not yet provide cause for
concern regarding population-level impacts. Despite the UME, the
relevant population of humpback whales (the Gulf of Maine humpback
whale stock) is characterized by a positive trend in abundance of
approximately 2.8 percent (Hayes et al. 2020).
Beginning in January 2017, elevated minke whale strandings have
occurred along the Atlantic coast from Maine through South Carolina,
with highest numbers in Massachusetts, Maine, and New York. This event
does not provide cause for concern regarding population level impacts,
as the population
[[Page 38051]]
abundance is greater than 20,000 whales.
Elevated numbers of harbor seal and gray seal mortalities were
first observed in July 2018 and have occurred across Maine, New
Hampshire, and Massachusetts. Based on tests conducted so far, the main
pathogen found in the seals is phocine distemper virus, although
additional testing to identify other factors that may be involved in
this UME are underway. The UME does not yet provide cause for concern
regarding population-level impacts to any of these stocks. For harbor
seals, the population abundance is over 75,000 and annual M/SI (350) is
well below PBR (2,006) (Hayes et al., 2020). The population abundance
for gray seals in the United States is over 27,000, with an estimated
abundance, including seals in Canada, of approximately 505,000. In
addition, the abundance of gray seals is likely increasing in the U.S.
Atlantic Exclusive Economic Zone as well as in Canada (Hayes et al.,
2020).
The required mitigation measures are expected to reduce the number
and/or severity of authorized takes for all species listed in Table 7,
including those with active UME's to the level of least practicable
adverse impact. In particular they would provide animals the
opportunity to move away from the sound source throughout the Project
Area before HRG survey equipment reaches full energy, thus preventing
them from being exposed to sound levels that have the potential to
cause injury (Level A harassment) or more severe Level B harassment. No
Level A harassment is anticipated, even in the absence of mitigation
measures, or authorized by NMFS.
NMFS expects that takes would be in the form of short-term Level B
harassment behavioral harassment by way of brief startling reactions
and/or temporary vacating of the area, or temporarily decreased
foraging (if such activity was occurring)--reactions that (at the scale
and intensity anticipated here) are considered to be of low severity,
with no lasting biological consequences. Since both the sources and
marine mammals are mobile, animals would only be exposed briefly to a
small ensonified area that might result in take. Additionally, required
mitigation measures would further reduce exposure to sound that could
result in more severe behavioral harassment.
Mayflower's planned HRG survey activities consist of 471 survey
days (conducted by up to four survey vessels) and the total trackline
distance is 14,350 km, which are identical to the values presented in
the initial proposed IHA (86 FR 11930; March 1, 2021) and any effects
or impacts are expected to be similar. Note that due to differences in
densities in the cable route corridors associated with the initial
proposed IHA compared to the issued IHA authorized takes in the issued
IHA have been reduced for 6 species (i.e., humpback whale, minke whale,
Atlantic white-sided dolphin, common dolphin, harbor porpoise and seal)
while authorized take has only increased for one species (i.e.,
bottlenose dolphin).
In summary and as described above, the following factors primarily
support our 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:
<bullet> No mortality or serious injury is anticipated or
authorized;
<bullet> No Level A harassment (PTS) is anticipated, even in the
absence of mitigation measures, or authorized;
<bullet> Take is anticipated to be limited to Level B behavioral
harassment consisting of brief startling reactions and/or temporary
avoidance of the Project Area;
<bullet> Due to the relatively small footprint of the survey
activities in relation to the size of feeding BIAs for North Atlantic
right, humpback, fin, and sei whales, the survey activities are not
expected to directly affect foraging success of these whale species;
<bullet> Foraging success is not likely to be significantly
impacted through effects on species that serve as prey species for
marine mammals, as effects from the survey are expected to be minimal;
<bullet> Alternate areas of nearby similar habitat value will be
available for marine mammals that temporarily vacate the Project Area
during the planned survey to avoid exposure to sounds from the
activity;
<bullet> While the Project Area is within areas noted as a
migratory BIA for North Atlantic right whales, the activities would
occur in such a comparatively small area such that any avoidance of the
Project Area due to activities would not affect migration. In addition,
mitigation measures to shutdown at 500 m to minimize potential for
Level B behavioral harassment would limit any take of the species;
<bullet> While the foraging areas south of Martha's Vineyard and
Nantucket overlap with the Project Area, prey for North Atlantic right
whales are mobile and broadly distributed. Therefore, North Atlantic
right whales are expected to be able to resume foraging once they have
moved away from any areas with disturbing noise levels, which would be
temporary in nature;
<bullet> The required mitigation measures, including visual
monitoring and shutdowns, are expected to minimize potential impacts to
marine mammals; and
<bullet> While UMEs are in effect for some species, the take from
Mayflower's activities is not expected to impact the reproduction or
survival of any individuals of any species, and therefore, is not
expected to impact annual rates of recruitment or survival either alone
or in combination with the effects of the UMEs.
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 required monitoring and
mitigation measures, NMFS finds that the total marine mammal take from
the planned 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. When the predicted number of
individuals to be taken is fewer than one third of the species or stock
abundance, the take is considered to be of small numbers. Additionally,
other qualitative factors may be considered in the analysis, such as
the temporal or spatial scale of the activities.
NMFS has authorized incidental take of 14 marine mammal species.
The total amount of authorized takes is less than 3 percent for all
species and stocks authorized for take except for sei whales (less than
22 percent), which NMFS finds are small numbers of marine mammals
relative to the estimated overall population abundances for those
stocks. See Table 7. Based on the analysis contained herein of the
planned activity (including the required mitigation and monitoring
measures) and the anticipated take of marine mammals, NMFS finds that
small numbers of marine mammals will be taken relative to the
population size of the affected species or stocks.
[[Page 38052]]
Unmitigable Adverse Impact Analysis and Determination
There are no relevant subsistence uses of the affected marine
mammal stocks or species implicated by this action. Therefore, NMFS has
determined that the total taking of affected species or stocks would
not have an unmitigable adverse impact on the availability of such
species or stocks for taking for subsistence purposes.
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 planned action (i.e., the issuance of an
incidental harassment authorization) with respect to potential impacts
on the human environment.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 (incidental harassment authorizations with
no anticipated serious injury or mortality) of the Companion Manual for
NOAA Administrative Order 216-6A, which do not individually or
cumulatively have the potential for significant impacts on the quality
of the human environment and for which we have not identified any
extraordinary circumstances that would preclude this categorical
exclusion. Accordingly, NMFS has determined that the issuance of the
IHA qualifies to be categorically excluded from further NEPA review.
Endangered Species Act (ESA)
Section 7(a)(2) of the Endangered Species Act of 1973 (16 U.S.C.
1531 et seq.) requires that each Federal agency insure that any action
it authorizes, funds, or carries out is not likely to jeopardize the
continued existence of any endangered or threatened species or result
in the destruction or adverse modification of designated critical
habitat. To ensure ESA compliance for the issuance of IHAs, NMFS
consults internally, in this case with the NMFS Greater Atlantic
Regional Fisheries Office (GARFO), whenever we propose to authorize
take for endangered or threatened species.
The NMFS Office of Protected Resources is authorizing the
incidental take of four species of marine mammals which are listed
under the ESA: Fin, sei, sperm, and North Atlantic right whales. We
requested initiation of consultation under section 7 of the ESA with
NMFS GARFO on March 5, 2021, for the issuance of this IHA. On March 5,
2021, NMFS GARFO determined our issuance of the IHA to Mayflower was
not likely to adversely affect the North Atlantic right, fin, sei, and
sperm whale or the critical habitat of any ESA-listed species or result
in the take of any marine mammals in violation of the ESA. GARFO
determined that since the issued IHA includes only a small modification
to the geographic scope of the survey activities they previously
consulted on and there are no additional effects to listed species
anticipated that were not already considered, no additional
consultation was necessary.
Authorization
NMFS has issued an IHA to Mayflower for the potential harassment of
small numbers of 14 marine mammal species incidental to the conducting
marine site characterization surveys offshore of Massachusetts and
Rhode Island in the area of the Commercial Lease of Submerged Lands for
Renewable Energy Development on the Outer Continental Shelf (OCS-A
0521) and along a potential submarine cable routes to landfall at
Falmouth, Massachusetts and Narraganset Bay, provided the previously
mentioned mitigation, monitoring and reporting requirements are
followed.
Catherine Marzin,
Acting Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2021-15243 Filed 7-16-21; 8:45 am]
BILLING CODE 3510-22-P
</pre><script data-cfasync="false" src="/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js"></script></body>
</html>Indexed from Federal Register on July 19, 2021.
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