[Federal Register Volume 86, Number 68 (Monday, April 12, 2021)]
[Notices]
[Pages 18943-18962]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-07419]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XB007]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Marine Site Characterization 
Surveys off of Delaware

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 
Skipjack Offshore Energy, LLC (Skipjack) to incidentally harass, by 
Level B harassment only, marine mammals during marine site 
characterization surveys offshore of Delaware in the area of the 
Commercial Lease of Submerged Lands for Renewable Energy Development on 
the Outer Continental Shelf (OCS-A 0519) and along potential submarine 
cable routes to a landfall location in Delaware.

DATES: This Authorization is effective for a period of one year, from 
April 5, 2021 through April 4, 2022.

FOR FURTHER INFORMATION CONTACT: Robert Pauline, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the applications 
and supporting documents, as well as a list of the references cited in 
this document, may be obtained by visiting the internet at: 
www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable. In case of 
problems accessing these documents, please call the contact listed 
above.

SUPPLEMENTARY INFORMATION:

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to 
allow, upon request, the incidental, but not intentional, taking of 
small numbers of marine mammals by U.S. citizens who engage in a 
specified activity (other than commercial fishing) within a specified 
geographical region if certain findings are made and either regulations 
are issued or, if the taking is limited to harassment, a notice of a 
proposed incidental take authorization may be provided to the public 
for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s) and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for taking for subsistence uses 
(where relevant). Further, NMFS must prescribe the permissible methods 
of taking and other ``means of effecting the least practicable adverse 
impact'' on the affected species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of such species or stocks for 
taking for certain subsistence uses (referred to in shorthand as 
``mitigation''); and requirements pertaining to the mitigation, 
monitoring and reporting of such takings are set forth.

Summary of Request

    On August 12, 2020, NMFS received a request from Skipjack for an 
IHA to take marine mammals incidental to marine site characterization 
surveys offshore of Delaware in the area of the Commercial Lease of 
Submerged Lands for Renewable Energy Development on the Outer 
Continental Shelf (OCS-A 0519) and along potential submarine cable 
routes to a landfall location in Delaware. Revised versions of the 
application were received on September 21, 2020 and November 5, 2020. 
The application was deemed adequate and complete on December 12, 2020. 
Skipjack's request is for take of a small number of 16 species of 
marine mammals by Level B harassment only. Neither Skipjack nor NMFS 
expects serious injury or mortality to result from this activity and, 
therefore, an IHA is appropriate.
    NMFS previously issued an IHA to Skipjack for similar work in the 
same geographic area on December 3, 2019 (84 FR 66156) with effectives 
dates from November 26, 2019 through November 25, 2020. Skipjack 
complied with all the requirements (e.g., mitigation, monitoring, and 
reporting) of the previous IHA and given the similarity in activities 
and location, relevant information regarding their previous marine 
mammal monitoring results may be found in the Estimated Take section.

Description of the Specified Activity

    Skipjack plans to conduct marine site characterization surveys, 
including high-resolution geophysical (HRG) surveys, in the area of 
OCS-A 0519 (Lease Area) and along potential submarine cable routes to 
landfall locations in Delaware over approximately 200 days. The purpose 
of the marine site characterization surveys are to obtain a baseline 
assessment of seabed (geophysical, geotechnical, and geohazard), 
ecological, and archeological conditions within the footprint of 
offshore wind facility development. Underwater sound resulting from 
Skipjack's planned activities, specifically certain acoustic sources 
planned for use during surveys, has the potential to result in 
incidental take of marine mammals in the form of behavioral harassment 
(i.e., Level B harassment only). Impulsive sources (e.g., sparker 
systems) would be utilized for 50 survey days while the non-impulsive 
sources (e.g., CHIRP sub-bottom profilers (SBPs)) would be used for the 
remaining 150 days. The survey activities planned by Skipjack are 
described in detail in the notice of proposed IHA (86 FR 11239; 
February 24, 2021). The HRG survey equipment that may be used by 
Skipjack are shown in Table 1.

[[Page 18944]]



                                                 Table 1--Summary of Representative HRG Survey Equipment
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   SLrms (dB    SL0-pk (dB
                                   Acoustic source    Operating       re 1         re 1     Pulse duration   Repetition   Beamwidth     CF= Crocker and
           Equipment                    type          frequency    [micro]Pa    [micro]Pa       (width)      rate (Hz)    (degrees)   Fratantonio (2016)
                                                        (kHz)          m)           m)       (millisecond)                            MAN = Manufacturer
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                       Non-impulsive, Non-parametric, Shallow Sub-bottom Profilers (CHIRP Sonars)
--------------------------------------------------------------------------------------------------------------------------------------------------------
ET 216 (2000DS or 3200 top       Non-impulsive,             2-16          195  ...........              20            6           24  MAN.
 unit).                           mobile,                    2-8
                                  intermittent.
ET 424.........................  Non-impulsive,             4-24          176  ...........             3.4            2           71  CF.
                                  mobile,
                                  intermittent.
ET 512.........................  Non-impulsive,           0.7-12          179  ...........               9            8           80  CF.
                                  mobile,
                                  intermittent.
GeoPulse 5430A.................  Non-impulsive,             2-17          196  ...........              50           10           55  MAN.
                                  mobile,
                                  intermittent.
Teledyne Benthos Chirp III--TTV  Non-impulsive,              2-7          197  ...........              60           15          100  MAN.
 170.                             mobile,
                                  intermittent.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                               Impulsive, Medium Sub-bottom Profilers (Sparkers & Boomers)
--------------------------------------------------------------------------------------------------------------------------------------------------------
AA, Dura-spark UHD (400 tips,    Impulsive, mobile.      0.3-1.2          203          211             1.1            4         Omni  CF.
 500 J).
AA, Dura-spark UHD (400+400)...  Impulsive, mobile.      0.3-1.2          203          211             1.1            4         Omni  CF (AA Dura-spark
                                                                                                                                       UHD Proxy).
GeoMarine, Geo-Source dual 400   Impulsive, mobile.        0.4-5          203          211             1.1            2         Omni  CF (AA Dura-spark
 tip sparker (800 J).                                                                                                                  UHD Proxy).
GeoMarine Geo-Source 200 tip     Impulsive, mobile.      0.3-1.2          203          211             1.1            4         Omni  CF (AA Dura-spark
 sparker (400 J).                                                                                                                      UHD Proxy).
GeoMarine Geo-Source 200-400     Impulsive, mobile.      0.3-1.2          203          211             1.1            4         Omni  CF (AA Dura-spark
 tip sparker (400 J).                                                                                                                  UHD Proxy).
AA, triple plate S-Boom (700-    Impulsive, mobile.        0.1-5          205          211             0.6            4           80  CF.
 1,000 J).
--------------------------------------------------------------------------------------------------------------------------------------------------------

    As described above, a detailed description of Skipjack's planned 
surveys is provided in the Federal Register notice for the proposed IHA 
(86 FR 11239; February 24, 2021). Since that time, no changes have been 
made to the planned 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).

Comments and Responses

    A notice of NMFS's proposal to issue an IHA to Skipjack was 
published in the Federal Register on February 24, 2021 (86 FR 11239). 
During the 30-day comment period, NMFS received comments from: (1) 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, Wildlife Conservation Society, Surfrider 
Foundation, Mass Audubon, Friends of the Earth, International Fund for 
Animal Welfare, NY4WHALES, WDC Whale and Dolphin Conservation, Marine 
Mammal Alliance Nantucket, Gotham Whale, All Our Energy, Seatuck 
Environmental Association, Inland Ocean Coalition, Nassau Hiking & 
Outdoor Club, and Connecticut Audubon Society; and (2) the Delaware 
Department of Resources and Environmental Control (DNREC).
    NMFS has posted the comments online at: www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable. Please see the letters for full detail and 
rationale for the comments.
    Comment 1: 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: At the outset of their letter, the ENGOs note that the 
comments reflect overarching concerns regarding NMFS' IHAs for marine 
site characterization survey (including HRG survey) activities required 
for offshore wind energy development, as well as their intention that 
the comments be considered in relation to all authorizations associated 
with marine site characterization activities for offshore wind energy 
off the U.S. East Coast. The comments provided in the letter apparently 
focus concern on available data regarding the Massachusetts and Rhode 
Island and Massachusetts Wind Energy Areas, and on North Atlantic right 
whale habitat usage within those areas. As such, the specific comments 
pertaining to those data and right whale habitat usage within those 
areas are not germane to this specific action, i.e., issuance of an IHA 
associated with HRG survey activity off of Delaware. We address the 
general comments regarding sufficiency of the available data on marine 
mammal occurrence below.
    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

[[Page 18945]]

of those models, is available at seamap.env.duke.edu/models/Duke-EC-GOM-2015/. 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 eight 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 five 
discrete regions. This most recent update--model version 9 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:
    [cir] 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.
    [cir] 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. The commenters 
do not cite this most recent report, and the comments suggest that the 
aforementioned data collected by the New England Aquarium is not 
reflected in the model. Therefore, it is unclear whether the commenters 
are aware of the most recently available data, which is used herein.
    As noted above, NMFS has determined that the Roberts et al. suite 
of density models represent the best available scientific information, 
and we specifically note that the most recent version of the North 
Atlantic right whale model may address some of the specific concerns 
provided by the commenters. However, NMFS acknowledges that there will 
always be additional data that is not reflected in the models and that 
may inform our analyses, whether because the data were not made 
available to the model authors or because the data is more recent than 
the latest model version for a specific taxon. NMFS will review any 
recommended data sources 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.
    The ENGOs cited several additional sources of information that are 
not reflected in currently available density models, including 
sightings databases and passive acoustic monitoring (PAM) efforts. 
However, no specific recommendations were made with regard to use of 
this information in informing the take estimates. Rather, the 
commenters reference a disparate array of data sources (some which are 
indeed reflected in the most recent models) and suggest 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 IHA 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 Skipjack.
    Comment 2: The ENGOs noted that the Roberts et al. model does not 
differentiate between species of pilot whale or seal or between stocks 
of bottlenose dolphin. The ENGOs express concern that, as a result, 
NMFS may not conduct the appropriate species-or stock-specific 
negligible impact analysis. The ENGOs also imply that use of these 
models may produce inaccurate take numbers by stating that 
``[m]iscalculation of take levels based on incomplete data could have 
serious implications for the future conservation of these species and 
stocks.''
    Response: The MMPA requires that species- or stock-specific 
negligible impact determinations be made, and NMFS has done so. In this 
case, NMFS has authorized take numbers specific to each affected 
species or stock. As a general matter, NMFS is unaware of any available 
density data which differentiates between species of pilot whales or 
seals, or stocks of bottlenose dolphins. However, lack of such data 
does not preclude the requisite species- or stock-specific findings. In 
the event that an amount of take is authorized at the guild or species 
level only, e.g., for pilot whales or bottlenose dolphins, 
respectively, NMFS may adequately evaluate the effects of the activity 
by conservatively assuming (for example) that all takes authorized for 
the guild or species would accrue to each potentially affected species 
or stock. In this case, NMFS has apportioned the overall take number 
for bottlenose dolphins according to stock, as described in the 
Estimated Take section and, for pilot whales, has assigned take on the 
basis of an assumed group size of 10 for each potentially affected 
species. NMFS does not agree that use of these models is likely to 
result in miscalculation of take levels, and the commenters do not 
provide support for this statement.
    Comment 3: The ENGOs assert that NMFS has not acknowledged the use 
of areas south of Nantucket and Martha's Vineyard as important habitat 
for foraging and social behavior for North Atlantic right whales, but 
rather that

[[Page 18946]]

NMFS believes the areas are important solely as a migratory pathway. 
The commenters also asserted that NMFS is overly reliant on the 
description of biologically important areas (BIA) provided in LaBrecque 
et al. (2015), stating that ``NMFS should not rely on the North 
Atlantic right whale migratory corridor BIA as the sole indicator of 
habitat importance for the species.''
    Response: The specified activity associated with the IHA addressed 
herein is located off of Delaware. Therefore, this comment is not 
relevant to issuance of this IHA. However, as a general matter, NMFS 
disagrees with the commenters' assertion. Although NMFS has in other 
notices discussed at length the use of the referenced area as a 
migratory pathway (and recognition of such use through the area's 
description as a BIA for right whales), we have also acknowledged the 
more recent data and its implications for the use of the referenced 
area (see, e.g., 85 FR 63508; December 7, 2018; 86 FR 11930; March 1, 
2021). Similarly, NMFS does not agree with the assertion that our 
understanding of important habitat for marine mammals stems solely from 
existing, described BIAs. NMFS concurs with the statement that BIAs are 
not comprehensive and are intended to be periodically reviewed and 
updated and we routinely review newly available information to inform 
our understanding of important marine mammal habitat. In this case, the 
specified geographical region does not include important habitat other 
than that described as being the migratory pathway for right whales.
    Comment 4: The ENGOs commented that the waters off Cape Hatteras, 
North Carolina, have high marine mammal biodiversity and that marine 
mammals occur at unusually high densities off Cape Hatteras compared to 
other areas along the East Coast. The ENGOs asserted that this area 
demands special attention from NMFS.
    Response: NMFS concurs with the commenters regarding the importance 
of deepwater areas off of Cape Hatteras. However, the specific activity 
associated with the IHA addressed herein does not occur off of Cape 
Hatteras and, in general, the site characterization surveys conducted 
in support of wind energy development that are the subject of the ENGO 
comment letter occur in shallow water (not the area of high 
biodiversity and density referenced by commenters). When appropriate, 
NMFS has accorded special attention to the development of additional 
mitigation for activities conducted in that location (e.g., 83 FR 
63268; December 7, 2018). NMFS uses the best available scientific 
information when analyzing potential impacts to marine mammals and in 
developing prescribed mitigation sufficient to meet the MMPA's ``least 
practicable adverse impact'' standard, and has done so in this case.
    Comment 5: The ENGOs asserted that NMFS must analyze cumulative 
impacts to North Atlantic right whales and other marine mammal species 
and stocks and ensure appropriate mitigation of these cumulative 
impacts. The commenters express particular concern about the cumulative 
impacts of survey activities off Rhode Island and Massachusetts on 
North Atlantic right whales. They further recommended that NMFS develop 
programmatic incidental take regulations applicable to site 
characterization activities.
    Response: Neither the MMPA nor NMFS' codified implementing 
regulations call for consideration of other unrelated activities and 
their impacts on populations. The preamble for NMFS' implementing 
regulations (54 FR 40338; September 29, 1989) states in response to 
comments that the impacts from other past and ongoing anthropogenic 
activities are to be incorporated into the negligible impact analysis 
via their impacts on the baseline. Consistent with that direction, NMFS 
has factored into its negligible impact analysis the impacts of other 
past and ongoing anthropogenic activities via their impacts on the 
baseline, e.g., as reflected in the density/distribution and status of 
the species, population size and growth rate, and other relevant 
stressors. The 1989 implementing regulations also addressed public 
comments regarding cumulative effects from future, unrelated 
activities. There NMFS stated that such effects are not considered in 
making findings under section 101(a)(5) concerning negligible impact. 
In this case, both this IHA, as well as other IHAs currently in effect 
or proposed within the specified geographic region, are appropriately 
considered an unrelated activity relative to the others. The IHAs are 
unrelated in the sense that they are discrete actions under section 
101(a)(5)(D), issued to discrete applicants.
    Section 101(a)(5)(D) of the MMPA requires NMFS to make a 
determination that the take incidental to a ``specified activity'' will 
have a negligible impact on the affected species or stocks of marine 
mammals. NMFS' implementing regulations require applicants to include 
in their request a detailed description of the specified activity or 
class of activities that can be expected to result in incidental taking 
of marine mammals. 50 CFR 216.104(a)(1). Thus, the ``specified 
activity'' for which incidental take coverage is being sought under 
section 101(a)(5)(D) is generally defined and described by the 
applicant. Here, Skipjack was the applicant for the IHA, and we are 
responding to the specified activity as described in that application 
(and making the necessary findings on that basis).
    Through the response to public comments in the 1989 implementing 
regulations, we also indicated (1) that NMFS would consider cumulative 
effects that are reasonably foreseeable when preparing a NEPA analysis, 
and (2) that reasonably foreseeable cumulative effects would also be 
considered under section 7 of the ESA for ESA-listed species. In this 
case, cumulative impacts have been adequately addressed under NEPA in 
prior environmental analyses that form the basis for NMFS' 
determination that this action is appropriately categorically excluded 
from further NEPA analysis. Regarding activities in the Mid- and South 
Atlantic region, in 2018 NMFS signed a Record of Decision that (1) 
adopted the Bureau of Ocean Energy Management's 2014 Final Programmatic 
Environmental Impact Statement that evaluated the direct, indirect, and 
cumulative impacts of geological and geophysical survey activities on 
the Mid- and South Atlantic Outer Continental Shelf to support NMFS' 
analysis associated with issuance of incidental take authorizations 
pursuant to sections 101(a)(5)(A) or (D) of the MMPA and the 
regulations governing the taking and importing of marine mammals (50 
CFR part 216), and (2) in accordance with 40 CFR 1505.2, announced and 
explained the basis for our decision to review and potentially issue 
incidental take authorizations under the MMPA on a case-by-case basis, 
if appropriate. Separately, NMFS has previously written Environmental 
Assessments (EA) that addressed cumulative impacts related to 
substantially similar activities, in similar locations, e.g., 2019 
Orsted EA for survey activities offshore southern New England; 2019 
Avangrid EA for survey activities offshore North Carolina and Virginia; 
2018 Deepwater Wind EA for survey activities offshore Delaware, 
Massachusetts, and Rhode Island.
    Separately, cumulative effects were analyzed as required through 
NMFS' required intra-agency consultation under section 7 of the ESA, 
which determined that NMFS' action of issuing the IHA is not likely to 
adversely affect listed marine mammals or their critical habitat.
    Finally, the ENGOs suggested that NMFS should promulgate 
programmatic

[[Page 18947]]

incidental take regulations for site characterization activities. 
Although NMFS is open to this approach, we have not received a request 
for such regulations. The ENGOs do not explain their apparent position 
that NMFS may advance regulations absent a requester.
    Comment 6: The ENGOs state that NMFS should not adjust estimated 
take numbers for large whales on the basis of assumed efficacy of 
mitigation requirements, and assert that NMFS' assumptions regarding 
effectiveness of mitigation requirements are unfounded.
    Response: In this case, NMFS did not propose to adjust downward any 
estimated take number based on proposed mitigation measures, and has 
not done so in the issued IHA. Therefore, the comment is not relevant 
to this specific action. Generally, NMFS does not agree with the 
apparent contention that it is never appropriate to reduce estimated 
take numbers based on anticipated implementation and effectiveness of 
mitigation measures, and will continue to evaluate the appropriateness 
of doing so on a case-specific basis.
    While we acknowledge the commenters' concerns regarding unfounded 
assumptions concerning the effectiveness of mitigation requirements in 
reducing actual take, it is important to also acknowledge the 
circumstances of a particular action. In most cases, the maximum 
estimated Level B harassment zone associated with commonly-used 
acoustic sources is approximately 150 meters (m), whereas the 
typically-required shutdown zone for North Atlantic right whales is 500 
m. For North Atlantic right whales, NMFS expects that this requirement 
will indeed be effective in reducing actual take below the estimated 
amount, which typically does not account for the beneficial effects of 
mitigation.
    Comment 7: The ENGOs state that NMFS must require mitigation 
measures that meet the least practicable adverse impact standard, imply 
that the requirements prescribed by NMFS have not met that standard, 
and recommend various measures that the commenters state NMFS should 
require.
    The ENGOs first state that NMFS should prohibit site assessment and 
characterization activities involving equipment with noise levels that 
the commenters assert could cause injury or harassment to North 
Atlantic right whales during periods of highest risk, which the 
commenters define as times of highest relative density of animals 
during their migration, and times when mother-calf pairs, pregnant 
females, surface active groups, or aggregations of three or more whales 
are, or are expected to be, present. The commenters additionally state 
that NMFS should require that work commence only during daylight hours 
and good visibility conditions to maximize the probability that marine 
mammals are detected and confirmed clear of the exclusion zone before 
activities begin. If the activity is halted or delayed because of 
documented or suspected North Atlantic right whale presence in the 
area, the commenters state that NMFS should require operators to wait 
until daylight hours and good visibility conditions to recommence.
    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. 
NMFS also agrees with the commenters that certain recommended 
mitigation requirements, e.g., avoiding impacts in places and times of 
greatest importance to marine mammals, limiting operations to times of 
greatest visibility, would be effective in reducing impacts. However, 
the commenters fail entirely to establish that Skipjack's specified 
site assessment and characterization survey activities--or site 
assessment and characterization survey activities in general--would 
have impacts on North Atlantic right whales (or any other species) such 
that operational limitations would be warranted. In fact, NMFS 
considers 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. In that context, there is no need for more restrictive 
mitigation requirements, and the commenters offer no justification to 
the contrary.
    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 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 restrictions 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 8: The ENGOs recommended that NMFS establish an exclusion 
zone (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 has 
determined that the EZs included here are sufficiently protective. We 
note that the 500-m EZ for North Atlantic right whales exceeds the 
modeled distance to the largest Level B harassment isopleth distance 
(141 m) by a factor of more than three. The commenters do not provide 
any justification for the contention that the existing EZs are 
insufficient, and do not provide any rationale for their recommended 
alternatives (other than that they are larger).
    Comment 9: The ENGOs stated that NMFS' requirements related to 
visual monitoring are inadequate. The commenters specifically noted 
their belief that a requirement for one Protected Species Observer 
(PSO) to be

[[Page 18948]]

on duty during daylight hours is insufficient, and recommended that 
NMFS require the use of infrared equipment to support visual monitoring 
by PSOs during periods of darkness. DNREC also recommended that 
infrared equipment be used to support visual monitoring by PSOs during 
periods of darkness.
    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 only. 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. As far as visual monitoring at night, we have not 
historically required visual monitoring at night because available 
information demonstrated that such monitoring should not be considered 
effective. However, as night vision technology has continued to 
improve, NMFS has adapted its practice, and two PSOs are required to be 
on duty at night. Moreover, NMFS has included a requirement in the 
final IHA that night-vision equipment (i.e., night-vision goggles and/
or infrared technology) must be available for use.
    Regarding specific technology cited by the ENGOs, NMFS appreciates 
the suggestion and agrees that relatively new detection platforms have 
shown promising results. Following review of the ENGO's letter, we 
considered these and other supplemental platforms as suggested. 
However, to our knowledge, there is no clear guidance available for 
operators regarding characteristics of effective systems, and the 
detection systems cited by the commenters are typically extremely 
expensive, and are therefore considered impracticable for use in most 
surveys. The commenters do not provide specific suggestions with regard 
to recommended systems or characteristics of systems. NMFS does not 
generally consider requirements to use systems such as those cited by 
the commenters to currently be practicable.
    Comment 10: The ENGOs recommended that NMFS should require PAM at 
all times, both day and night, to maximize the probability of detection 
for North Atlantic right whales, and other species and stocks. DNREC 
echoed this recommendation.
    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 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 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 11: The ENGOs recommended that NMFS require applicants to 
use the lowest practicable source level.
    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 12: 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

[[Page 18949]]

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 dynamic management area (DMA) or seasonal management area 
(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 13: The ENGOs recommend that NMFS work with relevant 
experts and stakeholders towards developing a robust and effective near 
real-time monitoring and mitigation system for North Atlantic right 
whales and other endangered and protected species (e.g., fin, sei, 
minke, and humpback whales) 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 
NMFS publication ``Technical Memorandum NMFS[hyphen]OPR[hyphen]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 14: The ENGOs state that NMFS must not issue Renewal IHAs, 
and assert that the process is contrary to statutory requirements.
    Response: NMFS' IHA Renewal process meets all statutory 
requirements. All IHAs issued, whether an initial IHA or a Renewal IHA, 
are valid for a period of not more than one year. And the public has at 
least 30 days to comment on all proposed IHAs, with a cumulative total 
of 45 days for IHA Renewals. As noted above, the Comments and Responses 
section made clear that the agency was seeking comment on both the 
initial proposed IHA and the potential issuance of a Renewal for this 
project. Because any Renewal (as explained in the Comments and 
Responses section) is limited to another year of identical or nearly 
identical activities in the same location (as described in the 
Description of Specified Activity section) or the same activities that 
were not completed within the one-year period of the initial IHA, 
reviewers have the information needed to effectively comment on both 
the immediate proposed IHA and a possible one-year Renewal, should the 
IHA holder choose to request one in the coming months.
    While there will be additional documents submitted with a Renewal 
request, for a qualifying Renewal these will be limited to 
documentation that NMFS will 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 will also confirm, among other things, that the 
activities will 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 
will 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.
    Comment 15: The ENGOs expressed concern about past instances where 
NMFS has modified issued IHAs in response to preliminary monitoring 
data indicating that certain species of marine mammal were being 
encountered more frequently than anticipated.
    Response: No modifications are included as part of this action and, 
therefore, this comment is not relevant to this IHA.

Changes From the Proposed IHA to Final IHA

    NMFS has revised the final IHA to include a section requiring that 
night-vision equipment (i.e., night-vision goggles and/or infrared 
technology) must be available for use during nighttime monitoring. NMFS 
has also included language in the IHA stating that all 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 
and that 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.

[[Page 18950]]

    The language above was included in the text of the notice of 
proposed IHA but inadvertently omitted from the draft IHA. There were 
no other changes from the proposed IHA to the final IHA.

Description of Marine Mammals in the Area of the Specified Activity

    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.

                    Table 2--Marine Mammal Species Likely To Occur Near the Project Area That May Be Affected by Skipjack's Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                     ESA/ MMPA status;   Stock abundance (CV,
            Common name                  Scientific name              Stock           strategic (Y/N)      Nmin, most recent        PBR      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)....          0.8         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             6,802 (0.24; 5,573;              11         2.35
                                                                                                         2016).
    Sei whale......................  Balaenoptera borealis.  Nova Scotia...........  E/D; Y             6,292 (1.015; 3,098;            6.2          1.2
                                                                                                         see SAR).
    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 (0.30; 30,627;           306           21
                                                                                                         See SAR).
    Short finned pilot whale.......  Globicephala            Western North Atlantic  -/-;Y              28,924 (0.24; 23,637;           236          160
                                      macrorhynchus.                                                     See SAR).
    Bottlenose dolphin.............  Tursiops truncatus....  Western North Atlantic  -/-; N             62,851 (0.23; 51,914;           519           28
                                                              Offshore.              -/-;Y               See SAR).                       48    12.2-21.5
                                                             W.N.A. Northern                            6,639 (0.41,4 ,759,
                                                              Migratory Coastal.                         2016).
    Common dolphin.................  Delphinus delphis.....  Western North Atlantic  -/-; N             172,897 (0.21; 145,           1,452          399
                                                                                                         216; 2016).
    Atlantic white-sided dolphin...  Lagenorhynchus acutus.  Western North Atlantic  -/-; N             93,233 (0.71; 54,443;           544           26
                                                                                                         See SAR).
    Atlantic spotted dolphin.......  Stenella frontalis....  Western North Atlantic  -/-; N             39,921 (0.27; 32,032;           320            0
                                                                                                         2012).
    Risso's dolphin................  Grampus griseus.......  Western North Atlantic  -/-; N             35,493 (0.19; 30,289;           303         54.3
                                                                                                         See SAR).
Family Phocoenidae (porpoises):
    Harbor porpoise................  Phocoena phocoena.....  Gulf of Maine/Bay of    -/-; N             95,543 (0.31; 74,034;           851          217
                                                              Fundy.                                     See SAR).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals):
    Gray seal \4\..................  Halichoerus grypus....  Western North Atlantic  -/-; N             27,131 (0.19; 23,158,         1,389        5,410
                                                                                                         2016).

[[Page 18951]]

 
    Harbor seal....................  Phoca vitulina........  Western North Atlantic  -/-; N             75,834 (0.15; 66,884,         2,006          350
                                                                                                         2018).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or
  designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR 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\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual Mortality/Serious Injury (M/SI) often cannot be determined precisely and is in some cases presented as a
  minimum value or range. A CV associated with estimated mortality due to commercial fisheries is presented in some cases.
\4\ The NMFS stock abundance estimate applies to U.S. population only, however the actual stock abundance is approximately 451,431.

    As indicated above, all 16 species (with 17 managed stocks) in 
Table 2 temporally and spatially co-occur with the activity to the 
degree that take is reasonably likely to occur and has been authorized 
by NMFS.
    A detailed description of the of the species likely to be affected 
by Skipjack's surveys, including brief introductions to the species and 
relevant stocks as well as available information regarding population 
trends and threats, and information regarding local occurrence, were 
provided in the notice of proposed IHA (86 FR 11239; February 24, 
2021); since that time, we are not aware of any changes in the status 
of these species and stocks; therefore, detailed descriptions are not 
provided here. Please refer to that notice for these descriptions. 
Please also refer to NMFS' website (www.fisheries.noaa.gov/find-species) for generalized species accounts.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    The underwater noise from Skipjack's survey activities has the 
potential to result in behavioral harassment of marine mammals in the 
vicinity of the survey area. The notice of proposed IHA (86 FR 11239; 
February 24, 2021) included a discussion of the effects of 
anthropogenic noise on marine mammals and the potential effects of 
underwater noise from Skipjack's survey activities 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 11239; February 24, 
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.
    Level B harassment is the only type of take expected to result from 
these activities. Except with respect to certain activities not 
pertinent here, section 3(18) of the MMPA defines ``harassment'' as any 
act of pursuit, torment, or annoyance, which (i) has the potential to 
injure a marine mammal or marine mammal stock in the wild (Level A 
harassment); or (ii) has the potential to disturb a marine mammal or 
marine mammal stock in the wild by causing disruption of behavioral 
patterns, including, but not limited to, migration, breathing, nursing, 
breeding, feeding, or sheltering (Level B harassment).
    Authorized takes are by Level B harassment only. Based on the 
nature of the activity, even in the absence of mitigation, Level A 
harassment is neither anticipated nor authorized. The anticipated 
effectiveness of the required mitigation measures (i.e., exclusion 
zones and shutdown measures), discussed in detail below in Mitigation 
section, serves to strengthen the position that Level A harassment is 
not expected.
    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 take estimate.

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 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. Skipjack's planned activity includes 
the use of intermittent sources (HRG equipment) and therefore the 160 
dB re 1 [mu]Pa (rms) is applicable.

[[Page 18952]]

    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). Skipjack's planned activity includes the 
use of impulsive (e.g., sparkers and boomers) and non-impulsive (e.g., 
CHIRP) sources.
    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 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                     Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                     PTS onset acoustic thresholds * (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: Lpk,flat: 219 dB;   Cell 2: LE,LF,24h: 199 dB.
                                          LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3: Lpk,flat: 230 dB;   Cell 4: LE,MF,24h: 198 dB.
                                          LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: Lpk,flat: 202 dB;   Cell 6: LE,HF,24h: 173 dB.
                                          LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: Lpk,flat: 218 dB;   Cell 8: LE,PW,24h: 201 dB.
                                          LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater)....  Cell 9: Lpk,flat: 232 dB;   Cell 10: LE,OW,24h: 219 dB.
                                          LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
  calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
  thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
  has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to reflect American
  National Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as
  incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript
  ``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted within the
  generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates
  the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
  and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could
  be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible,
  it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
  exceeded.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that will feed into identifying the area ensonified above the 
acoustic thresholds, which include source levels and transmission loss 
coefficient.
    NMFS has developed a user-friendly methodology for determining the 
rms sound pressure level (SPLrms) at the 160-dB isopleth for 
the purposes of estimating the extent of Level B harassment isopleths 
associated with HRG survey equipment (NMFS, 2020). This methodology 
incorporates frequency and some directionality to refine estimated 
ensonified zones. For sources that operate with different beam widths, 
the maximum beam width was used (see Table 1). The lowest frequency of 
the source was used when calculating the absorption coefficient (Table 
1).
    NMFS considers the data provided by Crocker and Fratantonio (2016) 
to represent the best available information on source levels associated 
with HRG equipment and, therefore, recommends that source levels 
provided by Crocker and Fratantonio (2016) be incorporated in the 
method described above to estimate isopleth distances to the Level A 
and Level B harassment thresholds. In cases when the source level for a 
specific type of HRG equipment is not provided in Crocker and 
Fratantonio (2016), NMFS recommends that either the source levels 
provided by the manufacturer be used, or, in instances where source 
levels provided by the manufacturer are unavailable or unreliable, a 
proxy from Crocker and Fratantonio (2016) be used instead. Table 1 
shows the HRG equipment types that may be used during the planned 
surveys and the sound levels associated with those HRG equipment types.
    Results of modeling using the methodology described above indicated 
that, of the HRG survey equipment planned for use by Skipjack that has 
the potential to result in Level B harassment of marine mammals, sound 
produced by the Applied Acoustics Dura-Spark UHD sparkers and GeoMarine 
Geo-Source sparker would propagate furthest to the Level B harassment 
threshold (141 m; Table 6). As described above, only a portion of 
Skipjack's survey activity days will employ sparkers or boomers; 
therefore, for the purposes of the exposure analysis, it was assumed 
that sparkers would be the dominant acoustic source for 50 of the total 
200 survey activity days. For the remaining 150 survey days, the TB 
Chirp III (48 m) was assumed to be the dominant source. Thus, the 
distances to the isopleths corresponding to the threshold for Level B 
harassment for sparkers (141 m) and the TB Chirp III (48m) were used as 
the basis of the take calculation for all marine mammals 25 percent and 
75 percent of survey activity days, respectively. This is a 
conservative approach, as the actual sources used on individual survey 
days may produce smaller harassment distances.
    When the NMFS Technical Guidance was first published in 2016, in 
recognition of the fact that ensonified area/volume could be more 
technically challenging to predict because of the duration component in 
the new thresholds, NMFS developed a User Spreadsheet that includes 
tools to help predict a simple isopleth that can be used in conjunction 
with marine mammal density or occurrence to help predict takes. NMFS 
notes that because of some of the assumptions included in the methods 
used for these tools, it is anticipated that isopleths produced are 
typically going to be overestimates of some degree, which may result in 
some degree of overestimate of Level A harassment take. However, these 
tools offer the best way to predict appropriate isopleths when more 
sophisticated 3D modeling methods are not available, and NMFS continues 
to develop ways to quantitatively refine these tools, and will 
qualitatively address the output where appropriate. For mobile sources 
such as HRG equipment, the User Spreadsheet predicts the closest 
distance at which a stationary animal would not incur PTS if the sound 
source traveled by the animal in a straight line at a constant speed. 
Inputs used in the User Spreadsheet are shown in Table 4

[[Page 18953]]

and Table 5 and the resulting isopleths are reported in Table 6.

                                                Table 4--User Spreadsheet Inputs for Non-Impulsive, Non-Parametric, Shallow Sub-Bottom Profilers
                                                                                         [CHIRP Sonars]
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
              Device                         EdgeTech 216                    Edgetech 424                    Edgetech 512                   GeoPulse 5430                Teledyne Chirp III
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                        D1) Mobile source; non-         D1) Mobile source; non-         D1) Mobile source; non-        D1) Mobile source; non-        D1) Mobile source; non-
       Spreadsheet tab used             impulsive, intermittent         impulsive, intermittent         impulsive, intermittent        impulsive, intermittent        impulsive, intermittent
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Frequency used for Weighting        2; 16; 16; 6.2................  4; 24; 24; 6.2................  1.7; 12; 12; 6.2..............  2; 17; 17; 6.2...............  2; 7; 7; 6.2.
 Factor Adjustment (kHz) 1 2.
Source Level (RMS SPL)............  195...........................  176...........................  179...........................  196..........................  197.
Source Velocity (m/sec)...........  2.057.........................  2.057.........................  2.057.........................  2.057........................  2.057.
Pulse Duration (sec)..............  0.02..........................  0.0034........................  0.009.........................  0.05.........................  0.06.
1/Repetition rate (sec)...........  0.17..........................  0.5...........................  0.125.........................  0.1..........................  0.07.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Values for WFA represented = (LFC; MFC; HFC; PPW).
\2\ WFAs were selected in the User Spreadsheet for each marine mammal hearing group based on estimated hearing sensitivities of each group and the operational frequency of the source.


                                                           Table 5--User Spreadsheet Inputs for Impulsive, Medium Sub-Bottom Profilers
                                                                                      [Sparkers & Boomers]
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
              Device               AA, Dura-spark UHD (400 tips,     AA, Dura-spark UHD     GeoMarine, geo-source   GeoMarine geo-source    GeoMarine geo-source   AA, triple plate S boom (700-
----------------------------------           500 J) \1\                (400+400) \1\        dual 400 tip sparker    200 tip sparker (400     200-400 tip sparker            1,000 J) \2\
                                  --------------------------------------------------------       (800 J) \1\               J) \1\                (400 J) \1\      ------------------------------
                                                                                          ------------------------------------------------------------------------
       Spreadsheet tab used        F1) Mobile source: impulsive,     F1) Mobile source:      F1) Mobile source:      F1) Mobile source:      F1) Mobile source:    F1) Mobile source: impulsive,
                                            intermittent          impulsive, intermittent        impulsive,              impulsive,              impulsive,                 intermittent
                                                                                                intermittent            intermittent            intermittent
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Frequency used for Weighting       1............................  1......................  1.5...................  1.....................  1.....................  3.4.
 Factor Adjustment (kHz) *.
Source Level (RMS SPL; PK SPL)...  203; 211.....................  203; 211...............  203; 211..............  203; 211..............  203; 211..............  205; 211.
Source Velocity (m/sec)..........  2.057........................  2.057..................  2.057.................  2.057.................  2.057.................  2.057.
Pulse Duration (sec).............  0.0011.......................  0.0011.................  0.0011................  0.0011................  0.0011................  0.0006.
1/Repetition rate (sec)..........  0.25.........................  0.25...................  0.25..................  0.25..................  0.25..................  0.25.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ The Dura-spark measurements and specifications provided in Crocker and Fratantonio (2016) were used for all sparker systems planned for the survey. The data provided in Crocker and
  Fratantonio (2016) represent the most applicable data for similar sparker systems with comparable operating methods and settings when manufacturer or other reliable measurements are not
  available.
\2\ Crocker and Fratantonio (2016) provide S-Boom measurements using two different power sources (CSP-D700 and CSP-N). The CSP-D700 power source was used in the 700 J measurements but not in
  the 1,000 J measurements. The CSP-N source was measured for both 700 J and 1,000 J operations but resulted in a lower SL; therefore, the single maximum SL value was used for both operational
  levels of the S Boom.


Table 6--Modeled Radial Distances From HRG Survey Equipment to Isopleths
             Corresponding to Level B Harassment Thresholds
------------------------------------------------------------------------
                                                       Distance to Level
                                                          B harassment
                                                         threshold (m)
                        Source                        ------------------
                                                            (SPLrms
                                                           threshold)
------------------------------------------------------------------------
Non-impulsive, Non-parametric, Shallow SBPs:
    ET 216 CHIRP.....................................                  9
    ET 424 CHIRP.....................................                  4
    ET 512i CHIRP....................................                  6
    GeoPulse 5430....................................                 21
    TB CHIRP III.....................................                 48
Impulsive, Medium SBPs:
    AA Triple plate S-Boom (700/1,000 J).............                 34
    AA, Dura-spark UHD (500 J/400 tip)...............                141
    AA, Dura-spark UHD 400+400.......................                141
    GeoMarine, Geo-Source dual 400 tip sparker.......                141
    GeoMarine, Geo-Source 200 tip sparker............                141
    GeoMarine, Geo-Source 200-400 tip sparker........                141
------------------------------------------------------------------------

    Isopleth distances to Level A harassment thresholds for all types 
of HRG equipment and all marine mammal functional hearing groups were 
modeled using the NMFS User Spreadsheet and NMFS Technical Guidance 
(2018). The dual criteria (peak SPL and SELcum) were applied 
to all HRG sources using the modeling methodology as described

[[Page 18954]]

above, and the isopleth distances for each functional hearing group 
were then carried forward in the exposure analysis. Modeled distances 
to isopleths corresponding to the Level A harassment thresholds are 
very small for all marine mammals and stocks (<5 m) with the exception 
of HF cetaceans (36.5 m from GeoPulse 5430). Note that the modeled 
distances to isopleths corresponding to the Level A harassment 
threshold are also assumed to be conservative. Level A harassment would 
also be more likely to occur at close approach to the sound source or 
as a result of longer duration exposure to the sound source. In regards 
to the one HF cetacean that is likely to occur in Skipjack's Project 
Area, the harbor porpoise, it is a notoriously shy species which is 
known to avoid vessels. Harbor porpoise would also be expected to avoid 
a sound source prior to that source reaching a level that would result 
in injury (Level A harassment).
    Given the factors above, Level A harassment of marine mammals is 
neither anticipated nor authorized, even in the absence of mitigation 
measures. However, the required mitigation measures--including shutdown 
measures and a 100 m exclusion zone for all marine mammals including 
the harbor porpoise--are expected to even further minimize the 
potential for close approach or longer duration exposure to active HRG 
acoustic sources. Those mitigation measures in addition to the very 
small size of Level A harassment zones, strengthens NMFS' determination 
that the potential for any marine mammals to be taken by Level A 
harassment is considered so low as to be discountable. Skipjack did not 
request and NMFS has not authorized the take by Level A harassment of 
any marine mammals.

Marine Mammal Occurrence

    In this section we provide the information about the presence, 
density, or group dynamics of marine mammals that will inform the take 
calculations.
    The habitat-based density models produced by the Duke University 
Marine Geospatial Ecology Laboratory (Roberts et al., 2016, 2017, 2018, 
2020) represent the best available information regarding marine mammal 
densities in the planned survey area. The density data presented by 
Roberts et al. (2016, 2017, 2018, 2020) incorporates aerial and 
shipboard line-transect survey data from NMFS and other organizations 
and incorporates data from 8 physiographic and 16 dynamic oceanographic 
and biological covariates, and controls for the influence of sea state, 
group size, availability bias, and perception bias on the probability 
of making a sighting. These density models were originally developed 
for all cetacean taxa in the U.S. Atlantic (Roberts et al., 2016). In 
subsequent years, certain models have been updated based on additional 
data as well as certain methodological improvements. More information 
is available online at seamap.env.duke.edu/models/Duke-EC-GOM-2015/. 
Marine mammal density estimates in the survey area (animals/kilmeters 
squared (km\2\)) were obtained using the most recent model results for 
all taxa (Roberts et al., 2016, 2017, 2018, 2020). The updated models 
incorporate additional sighting data, including sightings from the NOAA 
Atlantic Marine Assessment Program for Protected Species (AMAPPS) 
surveys (e.g., NEFSC & SEFSC, 2011, 2012, 2014a, 2014b, 2015, 2016). 
For the exposure analysis, density data from Roberts et al. (2016, 
2017, 2018, 2020) were mapped using a geographic information system 
(GIS). Density grid cells that included any portion of the planned 
survey area were selected for all survey months.
    Densities from each of the selected density blocks were averaged 
for each month available to provide monthly density estimates for each 
species (when available based on the temporal resolution of the model 
products), along with the average annual density (Table 7).

           Table 7--Estimated Monthly and Average Annual Density (Animals/km-2) of Potentially Affected Marine Mammals Within the Project Area Based on Monthly Habitat Density Models
                                                                           [Roberts et al. 2016; Roberts, 2018, 2020]
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                                                                        Average
                                                                                                                                                                                         annual
                           Species                                Jan       Feb       Mar       Apr       May       Jun       Jul       Aug       Sep       Oct       Nov       Dec     density
                                                                                                                                                                                         (km-2)
 
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Low-Frequency Cetaceans:
    Fin whale................................................    0.0010    0.0008    0.0015    0.0020    0.0017    0.0012    0.0005    0.0004    0.0011    0.0014    0.0010    0.0009     0.0011
    Sei whale................................................    0.0000    0.0000    0.0000    0.0000    0.0000    0.0000    0.0000    0.0000    0.0000    0.0000    0.0000    0.0000     0.0000
    Minke whale..............................................    0.0002    0.0002    0.0002    0.0009    0.0010    0.0005    0.0001    0.0000    0.0001    0.0003    0.0001    0.0001     0.0003
    Humpback whale...........................................    0.0013    0.0006    0.0006    0.0005    0.0005    0.0004    0.0001    0.0001    0.0002    0.0004    0.0004    0.0014     0.0005
    North Atlantic right whale...............................    0.0037    0.0042    0.0043    0.0028    0.0002    0.0000    0.0000    0.0000    0.0000    0.0000    0.0003    0.0020     0.0015
Mid-Frequency Cetaceans:
    Sperm whale..............................................    0.0000    0.0000    0.0000    0.0000    0.0000    0.0001    0.0001    0.0001    0.0000    0.0001    0.0000    0.0000     0.0000
    Atlantic white-sided dolphin.............................    0.0017    0.0009    0.0012    0.0028    0.0035    0.0022    0.0006    0.0003    0.0008    0.0026    0.0036    0.0034     0.0020
    Atlantic spotted dolphin.................................    0.0017    0.0017    0.0017    0.0017    0.0017    0.0017    0.0017    0.0017    0.0017    0.0017    0.0017    0.0017     0.0017
    Common bottlenose dolphin (Offshore) \1\.................    0.0134    0.0088    0.0125    0.0193    0.1224    0.1138    0.1361    0.1663    0.0800    0.0713    0.0524    0.0201     0.0680
    Common bottlenose dolphin (Migratory) \1\................    0.0317    0.0271    0.0444    0.0910    0.5921    0.4623    0.5903    0.6439    0.2388    0.2015    0.1335    0.0459     0.2585
    Short-finned pilot whale \2\.............................    0.0003    0.0003    0.0003    0.0003    0.0003    0.0003    0.0003    0.0003    0.0003    0.0003    0.0003    0.0003     0.0003
    Long-finned pilot whale \2\..............................    0.0003    0.0003    0.0003    0.0003    0.0003    0.0003    0.0003    0.0003    0.0003    0.0003    0.0003    0.0003     0.0003
    Risso's dolphin..........................................    0.0000    0.0000    0.0000    0.0000    0.0000    0.0000    0.0000    0.0000    0.0000    0.0000    0.0000    0.0000     0.0000
    Common dolphin...........................................    0.0071    0.0035    0.0040    0.0092    0.0167    0.0110    0.0125    0.0143    0.0109    0.0109    0.0200    0.0152     0.0113
High-Frequency Cetaceans:
    Harbor porpoise..........................................    0.0261    0.0247    0.0225    0.0095    0.0031    0.0000    0.0000    0.0000    0.0000    0.0005    0.0153    0.0535     0.0129
Pinnipeds \3\:
    Gray seal................................................    0.0003    0.0003    0.0003    0.0003    0.0003    0.0007    0.0007    0.0007    0.0003    0.0003    0.0003    0.0003     0.0004
    Harbor seal..............................................    0.0003    0.0003    0.0003    0.0003    0.0003    0.0007    0.0007    0.0007    0.0003    0.0003    0.0003    0.0003     0.0004
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Bottlenose dolphin stocks were delineated based on the 20-m isobath as identified in NMFS 2017 SAR; all density blocks falling inland of the 20-m depth contour were assumed to belong to
  the migratory coastal stock, and those beyond this depth were assumed to belong to the offshore stock.
\2\ Roberts (2018) only provides density estimates for ``generic'' pilot whales. It is assumed that each species has density levels that are equivalent to the generic pilot whale Density
  levels.
\3\ Seal densities are not given by individual months or species, instead, seasons are divided as summer (June, July, August) and Winter (September-May) and applied to ``generic'' seals; as a
  result, reported seasonal densities for spring and fall are the same and are not provided for each species (Roberts 2018). Densities were evenly split between both species.

Take Calculation and Estimation

    Here NMFS describes how the information provided above is brought 
together to produce a quantitative take estimate. In order to estimate 
the number of marine mammals predicted to be exposed to sound levels 
that would result in harassment, radial distances to predicted 
isopleths corresponding to Level B harassment thresholds are 
calculated, as described above. Those distances are then used to 
calculate the area(s) around the HRG survey equipment predicted to be 
ensonified to sound levels that exceed

[[Page 18955]]

harassment thresholds. The area estimated to be ensonified to relevant 
thresholds in a single day is then calculated, based on areas predicted 
to be ensonified around the HRG survey equipment and the estimated 
trackline distance traveled per day by the survey vessel. The daily 
area is multiplied by the mean annual density of a given marine mammal 
species. This value is then multiplied by the number of planned vessel 
days.
    The estimated potential daily active survey distance of 70 km was 
used as the estimated areal coverage over a 24-hour period. This 
distance accounts for the vessel traveling at roughly 4 knots and only 
for periods during which equipment <180 kHz is in operation. A vessel 
traveling 4 knots can cover approximately 110 km per day; however, 
based on data from 2017, 2018, and 2019 surveys, survey coverage over a 
24-hour period is closer to 70 km per day. For daylight only vessels, 
the distance is reduced to 35 km per day. To maintain the potential for 
24-hour surveys, the Level B harassment ZOIs provided in Table 8 were 
calculated for each source based on the Level B harassment threshold 
distances in Table 6 with a 24-hour (70 km) operational period.

    Table 8--Calculated Zone of Influence (ZOI) Encompassing Level B
  Thresholds for Each Sound Source or Comparable Sound Source Category
------------------------------------------------------------------------
                         Source                            Level B ZOI
--------------------------------------------------------     (km\2\)
                                                        ----------------
                     Hearing group                             All
------------------------------------------------------------------------
ET 216 CHIRP...........................................              1.3
ET 424 CHIRP...........................................              0.6
ET 512i CHIRP..........................................              0.8
GeoPulse 5430..........................................              2.9
TB CHIRP III...........................................              6.7
AA Triple plate S-Boom (700-1,000 J)...................              4.8
AA, Dura-spark UHD.....................................             19.8
AA, Dura-spark UHD 400+400.............................             19.8
GeoMarine, Geo-Source dual 400 tip Sparker.............             19.8
------------------------------------------------------------------------
AA = Applied Acoustics; CHIRP = Compressed High-Intensity Radiated
  Pulse; ET = EdgeTech; HF = high-frequency; J = joules; LF = low-
  frequency; MF = mid-frequency; PW = phocid pinnipeds in water; SBP =
  sub-bottom profiler; TB = Teledyne Benthos; UHD = ultra-high
  definition.

    Level B exposures were estimated by multiplying the average annual 
density of each species (Table 7) (Roberts et al., 2016; Roberts, 2018) 
by the daily ZOI that was estimated to be ensonified to an 
SPLrms exceeding 160 dB re 1 [micro]Pa (Table 8), times the 
number of operating days expected for the survey in each area assessed. 
As described previously, it was assumed that that sparker systems with 
141-m Level B harassment isopleths would operate for 50 survey days and 
the non-sparker TB CHIRP III with 48-m Level B harassment isopleth 
would operate for the remaining 150 survey days. The results of these 
calculations are shown in Table 9.

                               Table 9--Summary of Take Numbers Authorized by NMFS
----------------------------------------------------------------------------------------------------------------
                                                                                      Level B       Max percent
                             Species                                 Abundance       takes\1\       population
----------------------------------------------------------------------------------------------------------------
Low-Frequency Cetaceans:
    Fin whale...................................................           7,418               2            0.03
    Sei whale...................................................           6,292           0 (1)            0.02
    Minke whale.................................................          24,202           0 (2)            0.01
    Humpback whale..............................................           1,396               2            0.14
    North Atlantic right whale..................................             428               3            0.70
Mid-Frequency Cetaceans:
    Sperm whale \3\.............................................           4,349           0 (3)            0.07
    Atlantic white-sided dolphin................................          93,233               4            0.00
    Atlantic spotted dolphin....................................          39,921       4 (2,000)            5.00
    Common bottlenose dolphin \2\:
        Offshore Stock..........................................          62,851             135            0.21
        Migratory Stock.........................................           6,639             516            7.77
    Pilot Whales \3\:
        Short-finned pilot whale................................          28,924          0 (10)            0.03
        Long-finned pilot whale.................................          39,215          0 (10)            0.03
    Risso's dolphin.............................................          35,493          0 (30)            0.08
    Common dolphin..............................................         178,825         24 (70)            0.04
High-Frequency Cetaceans:
Harbor porpoise.................................................          95,543              22            0.03
Pinnipeds:
    Seals \4\:
        Gray seal...............................................          27,131          0 (10)            0.04
        Harbor seal.............................................          75,834          0 (10)            0.01
----------------------------------------------------------------------------------------------------------------
\1\ Parenthesis denote changes from calculated take estimates.
\2\ Roberts et al. (2016) does not provide density estimates for individual stocks of common bottlenose
  dolphins; therefore, stock densities were delineated using the 20-m isobath.

[[Page 18956]]

 
\3\ Roberts (2018) only provides density estimates for ``generic'' pilot whales and seals; therefore, an equal
  potential for takes has been assumed either for species or stocks within the larger group.
\4\ Roberts (2018) only provides density estimates for ``generic'' seals; therefore, densities were split evenly
  between the two species.

    No takes were calculated for the sei whale, minke whale, sperm 
whale, short- and long-finned pilot whale, or Risso's dolphin. However, 
based on anticipated species distributions and data from previous 
surveys conducted in the DE WEA, it is possible that these species 
could be encountered. Therefore, Skipjack based its take requests on 
estimated group sizes for these species (1 for sei whales, 2 for minke 
whales, 3 for sperm whales, 10 for short- and long-finned pilot whales, 
and 30 for Risso's dolphins). For species with no modeled exposures, 
requested takes for HRG surveys are based on mean group sizes derived 
from the following references:
     Sei whale: Kenney and Vigness-Raposa, 2010;
     Minke whale: Kenney and Vigness-Raposa, 2020;
     Sperm whale: Barkaszi and Kelly, 2018;
     Short- and long-finned pilot whales: Kenney and Vigness-
Raposa, 2010; and
     Risso's dolphin: Barkaszi and Kelly, 2018.
    NMFS concurred with this approach and based its authorized takes of 
these species on Skipjack's requests. Additionally, the number of takes 
authorized in Table 9 for Atlantic white-sided dolphin, bottlenose 
dolphin, and harbor porpoise are equivalent to the numbers requested by 
Skipjack.
    Roberts et al. (2018) produced density models for all seals and did 
not differentiate by seal species. The take calculation methodology as 
described above resulted in close to zero takes. The marine mammal 
monitoring report associated with the previous IHA issued to Skipjack 
in this survey area (84 FR 66156; December 3, 2019) did not record any 
takes of seals. However, the planned survey area includes a portion of 
Delaware Bay which is not covered by Roberts et al. (2018) and was not 
included as part of the previous IHA. Therefore, Skipjack did not 
request take of any harbor or gray seals. However, since seals are 
known to occur in the Bay, mostly during winter months, NMFS is 
conservatively authorizing 10 takes of each species by Level B 
harassment of both harbor and gray seals.
    Skipjack had requested 4 takes of spotted dolphin and 24 takes of 
common dolphin by Level B harassment. However, recent HRG surveys in 
the Mid-Atlantic area off the coast of Virginia have recorded 
unexpectedly large numbers of both Atlantic spotted dolphin and common 
dolphin. These events have led NMFS to modify another offshore wind 
energy company's existing IHA (85 FR 81879; December 17, 2020) in order 
to accommodate larger take numbers. The spotted dolphins had been 
recorded at a rate of up 15 per day while common dolphins were recorded 
at a rate of 62 animals in a single week. Note that there were many 
days in which there were no sightings of spotted dolphins and that all 
of the 62 common dolphin sightings occurred during a single week. The 
previous Skipjack marine mammal monitoring report from this area 
recorded up to 8 common dolphins over 23 days of active surveying (0.35 
animals/day). Given this data, NMFS will assume that 0.35 common 
dolphins could be exposed within the Level B harassment zone per day 
over 200 days resulting in the 70 authorized takes of common dolphin by 
Level B harassment. NMFS will also assume that there could be up to 10 
exposures of spotted dolphin per day resulting in the 2000 authorized 
takes by Level B harassment.
    Note that Skipjack submitted a marine mammal monitoring report 
under the previous IHA covering the period of June 4, 2020 through June 
26, 2020. Over the 23-day monitoring period there were 110 sightings 
consisting of 112 individual animals. Only three bottlenose dolphins 
were recorded as occurring within estimated Level B harassment zones 
which is well below the 1,465 takes that were authorized. However, due 
to a range of factors only 23 actual survey days occurred out of 200 
that were planned.

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, impact on 
operations.

Mitigation for Marine Mammals and Their Habitat

    NMFS requires the following mitigation measures be implemented 
during Skipjack's planned marine site characterization surveys.

Marine Mammal Exclusion Zones and Harassment Zones

    Marine mammal EZs would be established around the HRG survey 
equipment and monitored by PSOs:
     500 m EZ for North Atlantic right whales during use of all 
acoustic sources;
     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

    Skipjack would implement a 30-minute pre-clearance period of the EZ 
prior to the initiation of ramp-up of

[[Page 18957]]

HRG equipment. During this period, the exclusion zone will be monitored 
by the PSOs, using the appropriate visual technology. Ramp-up may not 
be initiated if any marine mammal(s) is within its respective 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 would be used for 
HRG survey equipment capable of adjusting energy levels at the start or 
restart of survey activities. The ramp-up procedure would be used at 
the beginning of HRG survey activities in order to provide additional 
protection to marine mammals near the survey area by allowing them to 
vacate the area prior to the commencement of survey equipment operation 
at full power.
    A ramp-up would begin with the powering up of the smallest acoustic 
HRG equipment at its lowest practical power output appropriate for the 
survey. When technically feasible, the power would then be gradually 
turned up and other acoustic sources would be added.
    Ramp-up activities will be delayed if a marine mammal(s) enters its 
respective 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 would 
be 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 would 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.
    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 exclusion zone and belongs to a genus other than those 
specified.

Vessel Strike Avoidance

    Skipjack 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

[[Page 18958]]

create an imminent and serious threat to a person or vessel or to the 
extent that a vessel is restricted in its ability to maneuver and, 
because of the restriction, cannot comply.

Seasonal Operating Requirements

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

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. Skipjack would employ 
independent, dedicated, trained PSOs, meaning that the PSOs must (1) be 
employed by a third-party observer provider, (2) have no tasks other 
than to conduct observational effort, collect data, and communicate 
with and instruct relevant vessel crew with regard to the presence of 
marine mammals and mitigation requirements (including brief alerts 
regarding maritime hazards), and (3) have successfully completed an 
approved PSO training course appropriate for their designated task. On 
a case-by-case basis, non-independent observers may be approved by NMFS 
for limited, specific duties in support of approved, independent PSOs 
on smaller vessels with limited crew capacity operating in nearshore 
waters.
    The PSOs will be responsible for monitoring the waters surrounding 
each survey vessel to the farthest extent permitted by sighting 
conditions, including exclusion zones, during all HRG survey 
operations. PSOs will visually monitor and identify marine mammals, 
including those approaching or entering the established exclusion zones 
during survey activities. It will be the responsibility of the Lead PSO 
on duty to communicate the presence of marine mammals as well as to 
communicate the action(s) that are necessary to ensure mitigation and 
monitoring requirements are implemented as appropriate.
    During all HRG survey operations (e.g., any day on which use of an 
HRG source is planned to occur), a minimum of one PSO must be on duty 
during daylight operations on each survey vessel, conducting visual 
observations at all times on all active survey vessels during daylight 
hours (i.e., from 30 minutes prior to sunrise through 30 minutes 
following sunset). Two PSOs will be on watch during nighttime 
operations. The PSO(s) would ensure 360[deg] visual coverage around the 
vessel from the most appropriate observation posts and would conduct 
visual observations using binoculars and/or 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.
    PSOs must be equipped with binoculars and have the ability to 
estimate distance and bearing to detect marine mammals, particularly in 
proximity to exclusion zones. Reticulated binoculars must also be 
available to PSOs for use as appropriate based on conditions and 
visibility to support the sighting and monitoring of marine mammals. 
During nighttime operations, night-vision 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 would also 
conduct observations when the acoustic source is not operating for 
comparison of sighting rates and behavior with and without use of the 
active acoustic sources. Any observations of marine mammals by crew 
members aboard any vessel associated with the survey would be relayed 
to the PSO team.

[[Page 18959]]

    Data on all PSO observations would be recorded based on standard 
PSO collection requirements. This would include dates, times, and 
locations of survey operations; dates and times of observations, 
location and weather; details of marine mammal sightings (e.g., 
species, numbers, behavior); and details of any observed marine mammal 
behavior that occurs (e.g., noted behavioral disturbances).

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] and 
[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)
     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.) 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);
     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, Skipjack 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 Skipjack personnel discover an injured or dead 
marine mammal, Skipjack 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, Skipjack 
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).

[[Page 18960]]

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 assesses 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 9, 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 is 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 Activities on Marine Mammals and their 
Habitat section, 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 behavioral harassment in the form of 
temporary avoidance of the area or decreased foraging (if such activity 
was occurring), reactions that are considered to be of low severity and 
with no lasting biological consequences (e.g., Southall et al., 2007). 
Even repeated Level B harassment of some small subset of an overall 
stock is unlikely to result in any significant realized decrease in 
viability for the affected individuals, and thus would not result in 
any adverse impact to the stock as a whole. As described previously due 
to the nature of the operations, Level A harassment is not expected 
even in the absence of mitigation. The small size of the Level A 
harassment zones and the required shutdown zones for certain activities 
further bolster this conclusion.
    In addition to being temporary, the maximum expected harassment 
zone around a survey vessel is 141 m; 75 percent of survey days would 
include activity with a reduced acoustic harassment zone of 48 m per 
vessel, producing expected effects of particularly low severity. 
Therefore, the ensonified area surrounding each vessel is relatively 
small compared to the overall distribution of the animals in the area 
and their use of the habitat. Feeding behavior is not likely to be 
significantly impacted as prey species are mobile and are broadly 
distributed throughout the survey area; therefore, marine mammals that 
may be temporarily displaced during survey activities are expected to 
be able to resume foraging once they have moved away from areas with 
disturbing levels of underwater noise. Because of the temporary nature 
of the disturbance and the availability of similar habitat and 
resources in the surrounding area, the impacts to marine mammals and 
the food sources that they utilize are not expected to cause 
significant or long-term consequences for individual marine mammals or 
their populations.
    There are no rookeries, mating or calving grounds known to be 
biologically important to marine mammals within the planned survey area 
and there are no feeding areas known to be biologically important to 
marine mammals within the planned survey area. There is no designated 
critical habitat for any ESA-listed marine mammals in the planned 
survey 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 unusual mortality event (UME). 
Overall, findings support human interactions, specifically vessel 
strikes and entanglements, as the cause of death for the majority of 
right whales. The planned survey area overlaps a migratory corridor 
Biologically Important Area (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 
Delaware, 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 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 Skipjack's 
planned activities. Additionally, only very limited take by Level B 
harassment of North Atlantic right whales has been requested or is 
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 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 for use. NMFS does not anticipate North 
Atlantic right whales takes that would result from Skipjack's planned 
activities would impact annual rates of recruitment or survival. Thus, 
any takes that occur would not result in population level impacts.

Other Marine Mammal Species With Active UMEs

    As noted previously, there are several active UMEs occurring in the 
vicinity of Skipjack's planned survey area. Elevated humpback whale 
mortalities have occurred along the Atlantic coast from Maine through 
Florida since January 2016. Of the cases examined, approximately half 
had evidence of human interaction (ship strike or entanglement). The 
UME does not yet provide cause for concern regarding population-level 
impacts. Despite the UME, the relevant population of humpback whales 
(the West Indies breeding population, or distinct

[[Page 18961]]

population segment remains stable at approximately 12,000 individuals.
    Beginning in January 2017, elevated minke whale strandings have 
occurred along the Atlantic coast from Maine through South Carolina, 
with highest numbers in Massachusetts, Maine, and New York. This event 
does not provide cause for concern regarding population level impacts, 
as the likely population abundance is greater than 20,000 whales.
    Elevated numbers of harbor seal and gray seal mortalities were 
first observed in July 2018 and have occurred across Maine, New 
Hampshire, and Massachusetts. Based on tests conducted so far, the main 
pathogen found in the seals is phocine distemper virus, although 
additional testing to identify other factors that may be involved in 
this UME are underway. The UME does not yet provide cause for concern 
regarding population-level impacts to any of these stocks. For harbor 
seals, the population abundance is over 75,000 and annual M/SI (350) is 
well below PBR (2,006) (Hayes et al., 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 Economic Exclusion 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 9, 
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 survey 
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.
    NMFS expects that takes would be in the form of short-term Level B 
behavioral harassment by way of brief startling reactions and/or 
temporary vacating of the area, or decreased foraging (if such activity 
was occurring)--reactions that (at the scale and intensity anticipated 
here) are considered to be of low severity, with no lasting biological 
consequences. Since both the sources and marine mammals are mobile, 
animals would only be exposed briefly to a small ensonified area that 
might result in take. Additionally, required mitigation measures would 
further reduce exposure to sound that could result in more severe 
behavioral harassment.
    In summary and as described above, the following factors primarily 
support our 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;
     Foraging success is not likely to be significantly 
impacted as effects on species that serve as prey species for marine 
mammals from the survey are expected to be minimal;
     The availability of alternate areas of similar habitat 
value for marine mammals to temporarily vacate the survey area during 
the planned survey to avoid exposure to sounds from the activity;
     Take is anticipated to be primarily Level B behavioral 
harassment consisting of brief startling reactions and/or temporary 
avoidance of the survey area;
     While the survey area is within areas noted as a migratory 
BIA for North Atlantic right whales, the activities would occur in such 
a comparatively small area such that any avoidance of the survey area 
due to activities would not affect migration. In addition, mitigation 
measures to shutdown at 500 m to minimize potential for Level B 
behavioral harassment would limit any take of the species.
     The required mitigation measures, including visual 
monitoring and shutdowns, are expected to minimize potential impacts to 
marine mammals.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the 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 16 marine mammal species 
(with 17 managed stocks.) The total amount of takes authorized is less 
than eight percent for one stock (bottlenose dolphin northern coastal 
migratory stock) and less than one percent of all other species and 
stocks, which NMFS finds are small numbers of marine mammals relative 
to the estimated overall population abundances for those stocks. See 
Table 9. 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.

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 evaluate our proposed action (i.e., the promulgation of 
regulations and subsequent issuance of incidental take authorization) 
and alternatives with respect to potential impacts on the human 
environment.
    This action is consistent with categories of activities identified 
in Categorical Exclusion B4 of the Companion Manual for NAO 216-6A, 
which do not individually or cumulatively have the potential for 
significant impacts on the quality of the human environment and for 
which we have not identified any extraordinary circumstances that would 
preclude this categorical exclusion. Accordingly, NMFS has determined 
that the planned

[[Page 18962]]

action qualifies to be categorically excluded from further NEPA review.

Endangered Species Act

    Section 7(a)(2) of the Endangered Species Act of 1973 (16 U.S.C. 
1531 et seq.) requires that each Federal agency insure that any action 
it authorizes, funds, or carries out is not likely to jeopardize the 
continued existence of any endangered or threatened species or result 
in the destruction or adverse modification of designated critical 
habitat. To ensure ESA compliance for the issuance of IHAs, NMFS 
consults internally, in this case with the NMFS Greater Atlantic 
Regional Fisheries Office (GARFO), whenever we propose to authorize 
take for endangered or threatened species.
    The NMFS Office of Protected Resources is 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 April 2, 
2021, NMFS GARFO concurred with our determination that our issuance of 
the IHA to Skipjack is 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.

Authorization

    NMFS has issued an IHA to Skipjack for the potential harassment of 
small numbers of 16 marine mammal species incidental to the conducting 
marine site characterization surveys offshore of Delaware in the area 
of the Commercial Lease of Submerged Lands for Renewable Energy 
Development on the Outer Continental Shelf (OCS-A 0519) and along 
potential submarine cable routes to a landfall location in Delaware 
provided the previously mentioned mitigation, monitoring and reporting 
requirements are followed.

    Dated: April 6, 2021.
Catherine Marzin,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2021-07419 Filed 4-9-21; 8:45 am]
BILLING CODE 3510-22-P