[Federal Register Volume 86, Number 135 (Monday, July 19, 2021)]
[Notices]
[Pages 38033-38052]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[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: https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act. 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..........
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                                                     Boomer
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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 https://seamap.env.duke.edu/models/Duke/EC/ 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):
     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.
     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.
     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.
     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 https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance 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: https://www.fisheries.noaa.gov/resource/document/north-atlantic-right-whale-monitoring-and-surveillance-report-and-recommendations. 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; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species 
(e.g., physical and behavioral descriptions) may be found on NMFS's 
website (https://www.fisheries.noaa.gov/find-species).
    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: www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region and 
draft 2020 Atlantic and Gulf of Mexico Marine Mammal SARs available 
online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports.

[[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: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region/. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable
\3\ Potential biological removal, defined by the MMPA as the maximum number of animals, not including natural mortalities, that may be removed from a
  marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population size (OSP). Annual M/SI, found in NMFS' SARs,
  represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial fisheries, subsistence hunting, ship
  strike). Annual M/SI values often cannot be determined precisely and is in some cases presented as a minimum value.
\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 
(SELcum) and peak sound pressure level metrics. As dual 
metrics, NMFS considers onset of PTS (Level A harassment) to have 
occurred when either one of the two metrics is exceeded (i.e., metric 
resulting in the largest isopleth). The SELcum metric 
considers both level and duration of exposure, as well as auditory 
weighting functions by marine mammal hearing group.
    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: 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                     Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                     PTS onset acoustic thresholds * (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: Lpk,flat: 219 dB;   Cell 2: LE,LF,24h: 199 dB.
                                          LE,LF,24h: 183 dB.
Mid-Frequency (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 
(SPLrms) 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 SPLrms 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 SPLrms 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 SPLrms 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 SPLrms 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:
     A 500-m EZ would be required for North Atlantic right 
whales during use of all acoustic sources; and
     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:
     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.
     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;
     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;
     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.
     All vessels must maintain a minimum separation distance of 
500 m from right whales. If a whale is observed but cannot be confirmed 
as a species other than a right whale, the vessel operator must assume 
that it is a right whale and take appropriate action.
     All vessels must maintain a minimum separation distance of 
100 m from sperm whales and all other baleen whales.
     All vessels must, to the maximum extent practicable, 
attempt to maintain a minimum separation distance of 50 m from all 
other marine mammals, with an understanding that at times this may not 
be possible (e.g., for animals that approach the vessel).
     When marine mammals are sighted while a vessel is 
underway, the vessel shall take action as necessary to avoid violating 
the relevant separation distance (e.g., attempt to remain parallel to 
the animal's course, avoid excessive speed or abrupt changes in 
direction until the animal has left the area). If marine mammals are 
sighted within the relevant separation distance, the vessel must reduce 
speed and shift the engine to neutral, not engaging the engines until 
animals are clear of the area. This does not apply to any vessel towing 
gear or any vessel that is navigationally constrained.
     These requirements do not apply in any case where 
compliance would create an imminent and serious threat to a person or 
vessel or to the extent that a vessel is restricted in its ability to 
maneuver and, because of the restriction, cannot comply.
     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:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density).
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) Action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the action; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas).
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or

[[Page 38048]]

cumulative impacts from multiple stressors.
     How anticipated responses to stressors impact either: (1) 
Long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks.
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat).
     Mitigation and monitoring effectiveness.

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 [email protected]. The report must 
contain, at minimum, the following:
     PSO names and affiliations;
     Dates of departures and returns to port with port name;
     Dates and times (Greenwich Mean Time) of survey effort and 
times corresponding with PSO effort;
     Vessel location (latitude/longitude) when survey effort 
begins and ends; vessel location at beginning and end of visual PSO 
duty shifts;
     Vessel heading and speed at beginning and end of visual 
PSO duty shifts and upon any line change;
     Environmental conditions while on visual survey (at 
beginning and end of PSO shift and whenever conditions change 
significantly), including wind speed and direction, Beaufort sea state, 
Beaufort wind force, swell height, weather conditions, cloud cover, sun 
glare, and overall visibility to the horizon;
     Factors that may be contributing to impaired observations 
during each PSO shift change or as needed as environmental conditions 
change (e.g., vessel traffic, equipment malfunctions); and
     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:
     Watch status (sighting made by PSO on/off effort, 
opportunistic, crew, alternate vessel/platform);
     PSO who sighted the animal;
     Time of sighting;
     Vessel location at time of sighting;
     Water depth;
     Direction of vessel's travel (compass direction);
     Direction of animal's travel relative to the vessel;
     Pace of the animal;
     Estimated distance to the animal and its heading relative 
to vessel at initial sighting;
     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;
     Estimated number of animals (high/low/best);
     Estimated number of animals by cohort (adults, yearlings, 
juveniles, calves, group composition, etc.);
     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);
     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);
     Animal's closest point of approach and/or closest distance 
from the center point of the acoustic source;
     Platform activity at time of sighting (e.g., deploying, 
recovering, testing, data acquisition, other); and
     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:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and
     General circumstances under which the animal was 
discovered.
    In the unanticipated event of a ship strike of a marine mammal by 
any vessel involved in the activities covered by the IHA, 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:
     Time, date, and location (latitude/longitude) of the 
incident;
     Species identification (if known) or description of the 
animal(s) involved;
     Vessel's speed during and leading up to the incident;
     Vessel's course/heading and what operations were being 
conducted (if applicable);
     Status of all sound sources in use;
     Description of avoidance measures/requirements that were 
in place at the time of the strike and what additional measures were 
taken, if any, to avoid strike;
     Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, visibility) immediately preceding the 
strike;
     Estimated size and length of animal that was struck;
     Description of the behavior of the marine mammal 
immediately preceding and following the strike;
     If available, description of the presence and behavior of 
any other marine mammals immediately preceding the strike;
     Estimated fate of the animal (e.g., dead, injured but 
alive, injured and moving, blood or tissue observed in the water, 
status unknown, disappeared); and
     To the extent practicable, photographs or video footage of 
the animal(s).

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any responses (e.g., intensity, duration), the context 
of any responses (e.g., critical reproductive time or location, 
migration), as well as effects on habitat, and the likely effectiveness 
of the mitigation. 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:
     No mortality or serious injury is anticipated or 
authorized;
     No Level A harassment (PTS) is anticipated, even in the 
absence of mitigation measures, or authorized;
     Take is anticipated to be limited to Level B behavioral 
harassment consisting of brief startling reactions and/or temporary 
avoidance of the Project Area;
     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;
     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;
     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;
     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;
     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;
     The required mitigation measures, including visual 
monitoring and shutdowns, are expected to minimize potential impacts to 
marine mammals; and
     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