[Federal Register Volume 85, Number 102 (Wednesday, May 27, 2020)]
[Notices]
[Pages 31856-31882]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-11203]



[[Page 31855]]

Vol. 85

Wednesday,

No. 102

May 27, 2020

Part II





Department of Commerce





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National Oceanic and Atmospheric Administration





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Takes of Marine Mammals Incidental to Specified Activities; Taking 
Marine Mammals Incidental to Site Characterization Surveys Off the 
Coast of Massachusetts; Notice

  Federal Register / Vol. 85, No. 102 / Wednesday, May 27, 2020 / 
Notices  

[[Page 31856]]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XA065]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Site Characterization Surveys Off 
the Coast of Massachusetts

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice; proposed incidental harassment authorization; request 
for comments on proposed authorization and possible renewal.

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SUMMARY: NMFS has received a request from Mayflower Wind Energy LLC 
(Mayflower) for authorization to take marine mammals incidental to site 
characterization surveys off the coast of Massachusetts in the area of 
the Commercial Lease of Submerged Lands for Renewable Energy 
Development on the Outer Continental Shelf (OCS-A 0521) and along a 
potential submarine cable route to landfall at Falmouth, Massachusetts. 
Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting 
comments on its proposal to issue an incidental harassment 
authorization (IHA) to incidentally take marine mammals during the 
specified activities. NMFS is also requesting comments on a possible 
one-year renewal that could be issued under certain circumstances and 
if all requirements are met, as described in Request for Public 
Comments at the end of this notice. NMFS will consider public comments 
prior to making any final decision on the issuance of the requested 
MMPA authorizations and agency responses will be summarized in the 
final notice of our decision.

DATES: Comments and information must be received no later than June 26, 
2020.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service. Physical comments should be sent to 
1315 East-West Highway, Silver Spring, MD 20910 and electronic comments 
should be sent to [email protected].
    Instructions: NMFS is not responsible for comments sent by any 
other method, to any other address or individual, or received after the 
end of the comment period. Comments received electronically, including 
all attachments, must not exceed a 25-megabyte file size. Attachments 
to electronic comments will be accepted in Microsoft Word or Excel or 
Adobe PDF file formats only. All comments received are a part of the 
public record and will generally be posted online at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act without change. All personal identifying 
information (e.g., name, address) voluntarily submitted by the 
commenter may be publicly accessible. Do not submit confidential 
business information or otherwise sensitive or protected information.

FOR FURTHER INFORMATION CONTACT: Amy Fowler, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the application 
and supporting documents, as well as a list of the references cited in 
this document, may be obtained online at: https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act. In case of problems accessing these 
documents, please call the contact listed above.

SUPPLEMENTARY INFORMATION:

Background

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

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed action (i.e., the issuance of an 
incidental harassment authorization) with respect to potential impacts 
on the human environment.
    This action is consistent with categories of activities identified 
in Categorical Exclusion B4 (incidental harassment authorizations with 
no anticipated serious injury or mortality) of the Companion Manual for 
NOAA Administrative Order 216-6A, which do not individually or 
cumulatively have the potential for significant impacts on the quality 
of the human environment and for which we have not identified any 
extraordinary circumstances that would preclude this categorical 
exclusion. Accordingly, NMFS has preliminarily determined that the 
issuance of the proposed IHA qualifies to be categorically excluded 
from further NEPA review.
    We will review all comments submitted in response to this notice 
prior to concluding our NEPA process or making a final decision on the 
IHA request.

Summary of Request

    On January 17, 2020, NMFS received a request from Mayflower for an 
IHA to take marine mammals incidental to site characterization surveys 
in the area of the Commercial Lease of Submerged Lands for Renewable 
Energy Development on the Outer Continental Shelf (OCS-A 0521; Lease 
Area) and a submarine export cable route connecting the Lease Area to 
landfall in Falmouth, Massachusetts. A revised application was received 
on April 9, 2020. NMFS deemed that request to be adequate and complete. 
Mayflower's request is for take of a small number of 14 species of 
marine mammals by Level B harassment only. Neither Mayflower nor NMFS 
expects serious injury or mortality to result from this activity and, 
therefore, an IHA is appropriate.

Description of Proposed Activity

Overview

    Mayflower proposes to conduct marine site characterization surveys, 
including high-resolution geophysical (HRG) and geotechnical surveys, 
in the area of Commercial Lease of Submerged Lands for Renewable Energy 
Development on the Outer Continental

[[Page 31857]]

Shelf #OCS-A 0521 (Lease Area) and along a potential submarine cable 
route to landfall at Falmouth, Massachusetts.
    The purpose of the proposed surveys is to acquire geotechnical and 
HRG data on the bathymetry, seafloor morphology, subsurface geology, 
environmental/biological sites, seafloor obstructions, soil conditions, 
and locations of any man-made, historical, or archaeological resources 
within the Lease Area and export cable route to support development of 
offshore wind energy facilities. Up to three survey vessels may operate 
concurrently as part of the proposed surveys, but the three vessels 
will spend no more than a combined total of 215 days at sea. Underwater 
sound resulting from Mayflower's proposed site characterization surveys 
has the potential to result in incidental take of marine mammals in the 
form of behavioral harassment.

Dates and Duration

    The total duration of geophysical survey activities would be 
approximately 215 survey-days. This schedule is based on 24-hour 
operations in the offshore, deep-water portion of the Lease Area, and 
12-hour operations in shallow-water and nearshore areas of the export 
cable route. The surveys are expected to occur between June and 
September 2020.

Specific Geographic Region

    Mayflower's survey activities would occur in the Northwest Atlantic 
Ocean approximately 60 kilometers (km) south of Martha's Vineyard, 
Massachusetts. All survey effort would occur within U.S. Federal and 
state waters. Surveys would occur within the Lease Area and along a 
potential submarine cable route connecting the Lease Area and landfall 
at Falmouth, Massachusetts (see Figure 1 in Mayflower's IHA 
application).

Detailed Description of Specific Activity

    Mayflower's proposed marine site characterization surveys include 
HRG and geotechnical survey activities. These survey activities would 
occur within the Lease Area and within an export cable route between 
the Lease Area and Falmouth, Massachusetts. The Lease Area is 
approximately 515.5 square kilometers (km\2\; 127,388 acres) and lies 
approximately 20 nautical miles (38 km south-southwest of Nantucket. 
Water depths in the Lease Area are approximately 38-62 meters (m). For 
the purpose of this IHA the Lease Area and export cable route are 
collectively referred to as the Project Area.
    The proposed HRG and geotechnical survey activities are described 
below.

Geotechnical Survey Activities

    Mayflower's proposed geotechnical survey activities would include 
the following:
     Sample boreholes and vibracores to determine geological 
and geotechnical characteristics of sediments; and
     Seabed core penetration tests (CPTs) to determine 
stratigraphy and in situ conditions of the sub-surface sediments.
    Geotechnical investigation activities are anticipated to be 
conducted from up to two vessels, each equipped with dynamic 
positioning (DP) thrusters. Impacts to the seafloor from this equipment 
will be limited to the minimal contact of the sampling equipment, and 
inserted boring and probes.
    In considering whether marine mammal harassment is an expected 
outcome of exposure to a particular activity or sound source, NMFS 
considers the nature of the exposure itself (e.g., the magnitude, 
frequency, or duration of exposure), characteristics of the marine 
mammals potentially exposed, and the conditions specific to the 
geographic area where the activity is expected to occur (e.g., whether 
the activity is planned in a foraging area, breeding area, nursery or 
pupping area, or other biologically important area for the species). We 
then consider the expected response of the exposed animal and whether 
the nature and duration or intensity of that response is expected to 
cause disruption of behavioral patterns (e.g., migration, breathing, 
nursing, breeding, feeding, or sheltering) or injury.
    Geotechnical survey activities would be conducted from drill ships 
equipped with DP thrusters. DP thrusters would be used to position the 
sampling vessel on station and maintain position at each sampling 
location during the sampling activity. Sound produced through use of DP 
thrusters is similar to that produced by transiting vessels and DP 
thrusters are typically operated either in a similarly predictable 
manner or used for short durations around stationary activities. NMFS 
does not believe acoustic impacts from DP thrusters are likely to 
result in take of marine mammals in the absence of activity- or 
location-specific circumstances that may otherwise represent specific 
concerns for marine mammals (i.e., activities proposed in area known to 
be of particular importance for a particular species), or associated 
activities that may increase the potential to result in take when in 
concert with DP thrusters. In this case, we are not aware of any such 
circumstances. Therefore, NMFS believes the likelihood of DP thrusters 
used during the proposed geotechnical surveys resulting in harassment 
of marine mammals to be so low as to be discountable. As DP thrusters 
are not expected to result in take of marine mammals, these activities 
are not analyzed further in this document.
    Field studies conducted off the coast of Virginia to determine the 
underwater noise produced by CPTs and borehole drilling found that 
these activities did not result in underwater noise levels that 
exceeded current thresholds for Level B harassment of marine mammals 
(Kalapinski, 2015). Given the small size and energy footprint of CPTs 
and boring cores, NMFS believes the likelihood that noise from these 
activities would exceed the Level B harassment threshold at any 
appreciable distance is so low as to be discountable. Therefore, 
geotechnical survey activities, including CPTs, vibracores, and 
borehole drilling, are not expected to result in harassment of marine 
mammals and are not analyzed further in this document.

Geophysical Survey Activities

    Mayflower has proposed that HRG survey activities would be 
conducted continuously 24 hours per day in the deep-water portion of 
the Project Area, and 12 hours per day in the shallow-water portion of 
the survey area. Based on this operation schedule, the estimated total 
duration of the proposed activities would be a combined total of 215 
survey days. This includes 90 days of surveys in the Lease Area and 
deep-water section of the export cable route, 95 days in the shallow-
water section of the cable route, and 30 days in the very shallow 
section of the cable route (waters less than 5 m deep) (see Table 1). 
These estimated durations include potential weather down time.

            Table 1--Summary of Proposed HRG Survey Segments
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                                                             Duration
            Survey area              Operating schedule    (survey days)
------------------------------------------------------------------------
Lease Area and deep-water section   24 hours/day........              90
 of cable route.

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Shallow-water section of cable      12 hours/day                      95
 route.                              (daylight only).
Very shallow cable route..........  12 hours/day                      30
                                     (daylight only).
                                                         ---------------
    All areas combined............  ....................             215
------------------------------------------------------------------------

    The HRG survey activities will be supported by vessels of 
sufficient size to accomplish the survey goals in each of the specified 
survey areas. Surveys in each of the identified survey areas will be 
executed by a single vessel during any given campaign (i.e., no more 
than one survey vessel would operate in the Lease Area and deep-water 
section of the cable route at any given time, but there may be one 
survey vessel operating in the Lease Area and deep-water cable route, 
one vessel in the shallow-water section of the cable route, and one 
vessel in the very shallow waters of the cable route operating 
concurrently, for a total of three vessels conducting HRG surveys). HRG 
equipment will either by mounted to or towed behind the survey vessel 
at a typical survey speed of approximately 3 knots (kn; 5.6 km per 
hour). The geophysical survey activities proposed by Mayflower would 
include the following:
     Seafloor imaging (sidescan sonar) for seabed sediment 
classification purposes, to identify natural and man-made acoustic 
targets resting on the seafloor. The sonar device emits conical or fan-
shaped pulses down toward the seafloor in multiple beams at a wide 
angle, perpendicular to the path of the sensor through the water. The 
acoustic return of the pulses is recorded in a series of cross-track 
slices, which can be joined to form an image of the sea bottom within 
the swath of the beam. They are typically towed beside or behind the 
vessel or from an autonomous vehicle;
     Multibeam echosounder (MBES) to determine water depths and 
general bottom topography. MBES sonar systems project sonar pulses in 
several angled beams from a transducer mounted to a ship's hull. The 
beams radiate out from the transducer in a fan-shaped pattern 
orthogonally to the ship's direction;
     Medium penetration sub-bottom profiler (sparkers) to map 
deeper subsurface stratigraphy as needed. Sparkers create acoustic 
pulses from 50 Hz to 4 kHz omni-directionally from the source that can 
penetrate several hundred meters into the seafloor. Typically towed 
behind the vessel with adjacent hydrophone arrays to receive the return 
signals;
     Parametric sub-bottom profiler to provide high data 
density in sub-bottom profiles that are typically required for cable 
routes, very shallow water, and archaeological surveys. Typically 
mounted on the hull of the vessel or from a side pole; and
     Ultra-short baseline (USBL) positioning and Global 
Acoustic Positioning System (GAPS) to provide high accuracy ranges by 
measuring the time between the acoustic pulses transmitted by the 
vessel transceiver and the equipment transponder necessary to produce 
the acoustic profile. It is a two-component system with a hull or pole 
mounted transceiver and one to several transponders either on the 
seabed or on the equipment.
    Table 2 identifies the representative survey equipment that may be 
used in support of planned geophysical survey activities that operate 
below 180 kilohertz (kHz) and have the potential to cause acoustic 
harassment to marine mammals. The make and model of the listed 
geophysical equipment may vary depending on availability and the final 
equipment choices will vary depending upon the final survey design, 
vessel availability, and survey contractor selection. Geophysical 
surveys are expected to use several equipment types concurrently in 
order to collect multiple aspects of geophysical data along one 
transect. Selection of equipment combinations is based on specific 
survey objectives.

                                         Table 2--Summary of HRG Survey Equipment Proposed for Use by Mayflower
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                                                                                                                                               Pulse
      HRG equipment  category           Specific HRG equipment     Operating  frequency    Source level      Beamwidth     Typical pulse    repetition
                                                                       range  (kHz)          (dB rms)        (degrees)    duration  (ms)    rate  (Hz)
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Sparker............................  Geomarine Geo-Spark 800 J    0.25 to 5.............             203             180             3.4               2
                                      system.
Sub-bottom profiler................  Edgetech 3100 with SB-2-16S  2 to 16...............             179              65              10              10
                                      towfish.
                                     Innomar SES-2000 Medium-100  85 to 115.............             241               2               2              40
                                      Parametric.
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    The deployment of HRG survey equipment, including the equipment 
planned for use during Mayflower's proposed activity, produces sound in 
the marine environment that has the potential to result in harassment 
of marine mammals. Proposed mitigation, monitoring, and reporting 
measures are described in detail later in this document (please see 
Proposed Mitigation and Proposed Monitoring and Reporting).

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history, of the potentially affected species. 
Additional information regarding population trends and threats may be 
found in NMFS's Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species 
(e.g., physical and behavioral descriptions) may be found on NMFS's

[[Page 31859]]

website. (https://www.fisheries.noaa.gov/find-species).
    Table 3 lists all species or stocks for which take is expected and 
proposed to be authorized for this action, and summarizes information 
related to the population or stock, including regulatory status under 
the MMPA and ESA and potential biological removal (PBR), where known. 
For taxonomy, we follow Committee on Taxonomy (2019). 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 survey area. 
NMFS's stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS's U.S. Atlantic SARs. All values presented in Table 3 are the most 
recent available at the time of publication and are available in the 
2018 Atlantic and Gulf of Mexico Marine Mammal Stock Assessments (Hayes 
et al., 2019a), available online at: www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region 
or and draft 2019 Atlantic and Gulf of Mexico Marine Mammal Stock 
Assessments (Hayes et al. 2019b) available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports.

                    Table 3--Marine Mammals Known To Occur in the Project Area That May Be Affected by Mayflower's Proposed Activity
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                                                                                              Stock abundance
                                                                               ESA/MMPA       (CV, Nmin, most
           Common name              Scientific name           Stock             status;      recent abundance        Predicted       PBR \4\   Annual M/
                                                                             strategic (Y/      survey) \2\        abundance \3\                 SI \4\
                                                                                N) \1\
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                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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Family Balaenidae:
    North Atlantic right whale..  Eubalaena glacialis  Western North        E/D; Y          428 (0; 418; n/a).  535 (0.45) *......        0.9       5.56
                                                        Atlantic.
Family Balaenopteridae
 (rorquals):
    Humpback whale..............  Megaptera            Gulf of Maine......  -/-; N          1,396 (0; 1,380;    1,637 (0.07) *....         22      12.15
                                   novaeangliae.                                             See SAR).
Fin whale.......................  Balaenoptera         Western North        E/D; Y          7,418 (0.25;        4,633 (0.08)......         12       2.35
                                   physalus.            Atlantic.                            6,029; See SAR).
Sei whale.......................  Balaenoptera         Nova Scotia........  E/D; Y          6292 (1.015;        717 (0.30) *......        6.2          1
                                   borealis.                                                 3,098; see SAR)
                                                                                             236.
Minke whale.....................  Balaenoptera.......  Canadian East Coast  -/-; N          24,202 (0.3;        2,112 (0.05) *....       1189          8
                                  acutorostrata......                                        18,902; See SAR).
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                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Physeteridae:
    Sperm whale.................  Physeter             NA.................  E; Y            4349 (0.28;3,451;   5,353 (0.12)......        6.9          0
                                   macrocephalus.                                            See SAR).
Family Delphinidae:
    Long-finned pilot whale.....  Globicephala melas.  Western North        -/-; Y          5,636 (0.63;        18,977 (0.11) \5\.         35         38
                                                        Atlantic.                            3,464).
    Bottlenose dolphin..........  Tursiops spp.......  Western North        -/-; N          62,851 (0.23;       97,476 (0.06) \5\.        591         28
                                                        Atlantic Offshore.                   51,914; See SAR).
    Common dolphin..............  Delphinus delphis..  Western North        -/-; N          172,825 (0.21;      86,098 (0.12).....      1,452        419
                                                        Atlantic.                            145,216; See SAR).
    Atlantic white-sided dolphin  Lagenorhynchus       Western North        -/-; N          92,233 (0.71;       37,180 (0.07).....        544         26
                                   acutus.              Atlantic.                            54,433; See SAR).
    Risso's dolphin.............  Grampus griseus....  Western North        -/-; N          35,493 (0.19;       7,732 (0.09)......        303       54.3
                                                        Atlantic.                            30,289; See SAR).
Family Phocoenidae (porpoises):
    Harbor porpoise.............  Phocoena phocoena..  Gulf of Maine/Bay    -/-; N          95,543 (0.31;       45,089 (0.12) *...        851        217
                                                        of Fundy.                            74,034; See SAR).
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                                                         Order Carnivora--Superfamily Pinnipedia
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Family Phocidae (earless seals):
    Gray seal \6\...............  Halichoerus grypus.  Western North        -/-; N          27,131 (0.19;       N/A...............      1,389      5,688
                                                        Atlantic.                            23,158, 2016).
    Harbor seal.................  Phoca vitulina.....  Western North        -/-; N          75,834 (0.15;       N/A...............        345        333
                                                        Atlantic.                            66,884, 2018).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
  under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
  exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
  under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region/. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable

[[Page 31860]]

 
\3\ This information represents species- or guild-specific abundance predicted by recent habitat-based cetacean density models (Roberts et al., 2016,
  2017, 2018). These models provide the best available scientific information regarding predicted density patterns of cetaceans in the U.S. Atlantic
  Ocean, and we provide the corresponding abundance predictions as a point of reference. Total abundance estimates were produced by computing the mean
  density of all pixels in the modeled area and multiplying by its area. For those species marked with an asterisk, the available information supported
  development of either two or four seasonal models; each model has an associated abundance prediction. Here, we report the maximum predicted abundance.
\4\ Potential biological removal, defined by the MMPA as the maximum number of animals, not including natural mortalities, that may be removed from a
  marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population size (OSP). Annual M/SI, found in NMFS' SARs,
  represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial fisheries, subsistence hunting, ship
  strike). Annual M/SI values often cannot be determined precisely and is in some cases presented as a minimum value. All M/SI values are as presented
  in the draft 2019 SARs (Hayes et al., 2019).
\5\ Abundance estimates are in some cases reported for a guild or group of species when those species are difficult to differentiate at sea. Similarly,
  the habitat-based cetacean density models produced by Roberts et al. (2016, 2017, 2018) are based in part on available observational data which, in
  some cases, is limited to genus or guild in terms of taxonomic definition. Roberts et al. (2016, 2017, 2018) produced density models to genus level
  for Globicephala spp. and produced a density model for bottlenose dolphins that does not differentiate between offshore and coastal stocks.
\6\ 8 NMFS stock abundance estimate applies to U.S. population only, actual stock abundance is approximately 505,000.

    As indicated above, all 14 species (with 14 managed stocks) in 
Table 3 temporally and spatially co-occur with the activity to the 
degree that take is reasonably likely to occur, and we have proposed 
authorizing it. All species that could potentially occur in the 
proposed survey areas are included in Table 4 of the IHA application. 
However, the temporal and/or spatial occurrence of several species 
listed in Table 4 in the IHA application is such that take of these 
species is not expected to occur. The blue whale (Balaenoptera 
musculus), Cuvier's beaked whale (Ziphius cavirostris), four species of 
Mesoplodont beaked whale (Mesoplodon spp.), dwarf and pygmy sperm whale 
(Kogia sima and Kogia breviceps), and striped dolphin (Stenella 
coeruleoalba), typically occur further offshore than the Project Area, 
while short-finned pilot whales (Globicephala macrorhynchus) and 
Atlantic spotted dolphins (Stenella frontalis) are typically found 
further south than the Project Area (Hayes et al., 2019b). There are 
stranding records of harp seals (Pagophilus groenlandicus) in 
Massachusetts, but the species typically occurs north of the Project 
Area and appearances in Massachusetts usually occur between January and 
May, outside of the proposed survey dates (Hayes et al., 2019b). As 
take of these species is not anticipated as a result of the proposed 
activities, these species are not analyzed further.
    The following subsections provide additional information on the 
biology, habitat use, abundance, distribution, and the existing threats 
to the non-ESA-listed and ESA-listed marine mammals that are both 
common in the waters of the outer continental shelf (OCS) of Southern 
New England and have the likelihood of occurring, at least seasonally, 
in the Project Area and are, therefore, expected to potentially be 
taken by the proposed activities.

North Atlantic Right Whale

    The Western Atlantic stock of North Atlantic right whales ranges 
primarily from calving grounds in coastal waters of the southeastern 
United States to feeding grounds in New England waters and the Canadian 
Bay of Fundy, Scotian Shelf, and Gulf of St. Lawrence (Hayes et al., 
2019). Surveys indicate that there are seven areas where NARWs 
congregate seasonally: The coastal waters of the southeastern United 
States, the Great South Channel, Jordan Basin, Georges Basin along the 
northeastern edge of Georges Bank, Cape Cod and Massachusetts Bays, the 
Bay of Fundy, and the Roseway Basin on the Scotian Shelf (Hayes et al. 
2018). The closest of these seven areas is the Great South Channel, 
which lies east of the Project Area, though none of these areas 
directly overlaps the Project Area.
    NMFS has designated two critical habitat areas for the NARW under 
the ESA: the Gulf of Maine/Georges Bank region, and the southeast 
calving grounds from North Carolina to Florida. NMFS's regulations at 
50 CFR part 224.105 designated nearshore waters of the Mid-Atlantic 
Bight as Mid-Atlantic U.S. Seasonal Management Areas (SMA) for right 
whales in 2008. SMAs were developed to reduce the threat of collisions 
between ships and right whales around their migratory route and calving 
grounds. All vessels greater than 19.8 m (65 ft) in overall length must 
operate at speeds of 10 knots (5.1 m/s) or less within these areas 
during specific time periods. The Lease Area is located approximately 
15 km southeast of the Block Island Sound SMA, which is active between 
November 1 and April 30 each year. The Great South Channel SMA lies to 
the northeast of the Lease Area and is active April 1 to July 31. NOAA 
Fisheries may also establish Dynamic Management Areas (DMAs) when and 
where NARWs are sighted outside SMAs. DMAs are generally in effect for 
two weeks. During this time, vessels are encouraged to avoid these 
areas or reduce speeds to 10 knots (5.1 m/s) or less while transiting 
through these areas.
    LaBrecque et al. 2015 identified ``biologically important areas 
(BIAs)'' for cetaceans on the U.S. East Coast, including reproductive, 
feeding, and migratory areas, as well as areas where small and resident 
populations reside. The Project Area is encompassed by a right whale 
BIA for migration from March to April and from November to December. A 
feeding BIA for right whales from April to June was identified 
northeast of the Project Area, east of Cape Cod.
    The western North Atlantic population demonstrated overall growth 
of 2.8 percent per year from 1990 to 2010, despite a decline in 1993 
and no growth between 1997 and 2000 (Pace et al. 2017). However, since 
2010 the population has been in decline, with a 99.99 percent 
probability of a decline of just under 1 percent per year (Pace et al. 
2017). Between 1990 and 2015, calving rates varied substantially, with 
low calving rates coinciding with all three periods of decline or no 
growth (Pace et al. 2017). In 2018, no new North Atlantic right whale 
calves were documented in their calving grounds; this represented the 
first time since annual NOAA aerial surveys began in 1989 that no new 
right whale calves were observed. However, in 2019 at least seven right 
whale calves were identified while ten calves have been recorded in 
2020. Data indicates that the number of adult females fell from 200 in 
2010 to 186 in 2015 while males fell from 283 to 272 in the same time 
period (Pace et al., 2017). In addition, elevated North Atlantic right 
whale mortalities have occurred since June 7, 2017. A total of 30 
confirmed dead stranded whales (21 in Canada; 9 in the United States), 
have been documented to date. This event has been declared an Unusual 
Mortality Event (UME), with human interactions (i.e., fishery-related 
entanglements and vessel strikes) identified as the most likely cause. 
More information is available online at: https://www.fisheries.noaa.gov/national/marine-life-distress/2017-2019-north-atlantic-right-whale-unusual-mortality-event.

Humpback Whale

    Humpback whales are found worldwide in all oceans. Humpback whales 
were listed as endangered under the Endangered Species Conservation Act 
(ESCA) in June 1970. In 1973, the ESA replaced the ESCA, and humpbacks 
continued to be listed as endangered. NMFS recently evaluated

[[Page 31861]]

the status of the species, and on September 8, 2016, NMFS divided the 
species into 14 distinct population segments (DPS), removed the current 
species-level listing, and in its place listed four DPSs as endangered 
and one DPS as threatened (81 FR 62259; September 8, 2016). The 
remaining nine DPSs were not listed. The West Indies DPS, which is not 
listed under the ESA, is the only DPS of humpback whale that is 
expected to occur in the Project Area. The best estimate of population 
abundance for the West Indies DPS is 12,312 individuals, as described 
in the NMFS Status Review of the Humpback Whale under the Endangered 
Species Act (Bettridge et al., 2015).
    Humpback whales in the Gulf of Maine stock typically feed in the 
waters between the Gulf of Maine and Newfoundland during spring, 
summer, and fall, but have been observed feeding in other areas, such 
as off the coast of New York (Sieswerda et al. 2015). Humpback whales 
are frequently piscivorous when in New England waters, feeding on 
herring (Clupea harengus), sand lance (Ammodytes spp.), and other small 
fishes, as well as euphausiids in the northern Gulf of Maine (Paquet et 
al. 1997). During winter, the majority of humpback whales from North 
Atlantic feeding areas (including the Gulf of Maine) mate and calve in 
the West Indies, where spatial and genetic mixing among feeding groups 
occurs, though significant numbers of animals are found in mid- and 
high-latitude regions at this time and some individuals have been 
sighted repeatedly within the same winter season, indicating that not 
all humpback whales migrate south every winter (Waring et al., 2017).
    Kraus et al. (2016) observed humpback whales in the RI/MA & MA WEAs 
and surrounding areas during all seasons. Humpback whales were observed 
most often during spring and summer months, with a peak from April to 
June. Calves were observed 10 times and feeding was observed 10 times 
during the Kraus et al. (2016) study. That study also observed one 
instance of courtship behavior. Although humpback whales were rarely 
seen during fall and winter surveys, acoustic data indicate that this 
species may be present within the Massachusetts Wind Energy Area (WEA) 
year-round, with the highest rates of acoustic detections in winter and 
spring (Kraus et al. 2016).
    A humpback whale BIA for feeding has been identified northeast of 
the Lease Area in the Gulf of Maine, Stellwagen Bank, and the Great 
South Channel from March through December (LaBrecque et al., 2015).
    Since January 2016, elevated humpback whale mortalities have 
occurred along the Atlantic coast from Maine through Florida. The event 
has been declared a UME. Partial or full necropsy examinations have 
been conducted on approximately half of the 111 known cases. A portion 
of the whales have shown evidence of pre-mortem vessel strike; however, 
this finding is not consistent across all of the whales examined so 
more research is needed. NOAA is consulting with researchers that are 
conducting studies on the humpback whale populations, and these efforts 
may provide information on changes in whale distribution and habitat 
use that could provide additional insight into how these vessel 
interactions occurred. More detailed information is available at: 
https://www.fisheries.noaa.gov/national/marine-life-distress/2016-2019-humpback-whale-unusual-mortality-event-along-atlantic-coast (accessed 
January 9, 2020). Three previous UMEs involving humpback whales have 
occurred since 2000, in 2003, 2005, and 2006.

Fin Whale

    The fin whale is the second largest baleen whale and is widely 
distributed in all the world's oceans, but is most abundant in 
temperate and cold waters (Aguilar and Garc[iacute]a-Vernet 2018). Fin 
whales are presumed to migrate seasonally between feeding and breeding 
grounds, but their migrations are less well defined than for other 
baleen whales. In the North Atlantic, some feeding areas have been 
identified but there are no known wintering areas (Aguilar and 
Garc[iacute]a-Vernet 2018). Fin whales are found in the summer from 
Baffin Bay, Spitsbergen, and the Barents Sea south to North Carolina 
and the coast of Portugal (Rice 1998). Apparently not all individuals 
migrate, because in winter they have been sighted from Newfoundland to 
the Gulf of Mexico and the Caribbean Sea, and from the Faroes and 
Norway south to the Canary Islands (Rice 1998). Fin whales off the 
eastern United States, Nova Scotia, and the southeastern coast of 
Newfoundland are believed to constitute a single stock under the 
present International Whaling Commission (IWC) management scheme 
(Donovan 1991), which has been called the Western North Atlantic stock.
    Kraus et al. (2016) suggest that, compared to other baleen whale 
species, fin whales have a high multi-seasonal relative abundance in 
the Rhode Island/Massachusetts and Massachusetts Wind Energy Areas (RI/
MA & MA WEAs) and surrounding areas. Fin whales were observed in the MA 
WEA) in spring and summer. This species was observed primarily in the 
offshore (southern) regions of the RI/MA & MA WEAs during spring and 
was found closer to shore (northern areas) during the summer months 
(Kraus et al. 2016). Calves were observed three times and feeding was 
observed nine times during the Kraus et al. (2016) study. Although fin 
whales were largely absent from visual surveys in the RI/MA & MA WEAs 
in the fall and winter months (Kraus et al. 2016), acoustic data 
indicated that this species was present in the RI/MA & MA WEAs during 
all months of the year.
    The main threats to fin whales are fishery interactions and vessel 
collisions (Waring et al., 2017). New England waters represent a major 
feeding ground for fin whales. The Lease Area is flanked by two BIAs 
for feeding fin whales--the area to the northeast is considered a BIA 
year-round, while the area off the tip of Long Island to the southwest 
is a BIA from March to October (LaBrecque et al. 2015).

Sei Whale

    Sei whales occur worldwide, with a preference for oceanic waters 
over shelf waters (Horwood 2018). The Nova Scotia stock of sei whales 
can be found in deeper waters of the continental shelf edge waters of 
the northeastern United States and northeastward to south of 
Newfoundland. NOAA Fisheries considers sei whales occurring from the 
U.S. East Coast to Cape Breton, Nova Scotia, and east to 42[deg] W as 
the Nova Scotia stock of sei whales (Waring et al. 2016; Hayes et al. 
2018). In the Northwest Atlantic, it is speculated that the whales 
migrate from south of Cape Cod along the eastern Canadian coast in June 
and July, and return on a southward migration again in September and 
October (Waring et al. 2014; 2017).
    Spring is the period of greatest abundance in U.S. waters, with 
sightings concentrated along the eastern margin of Georges Bank and 
into the Northeast Channel area, and along the southwestern edge of 
Georges Bank in the area of Hydrographer Canyon (Waring et al., 2015). 
Kraus et al. (2016) observed sei whales in the RI/MA and MA WEAs and 
surrounding areas only between the months of March and June during the 
2011-2015 NLPSC aerial survey. The number of sei whale observations was 
less than half that of other baleen whale species in the two seasons in 
which sei whales were observed (spring and summer). This species 
demonstrated a distinct seasonal habitat use pattern that was 
consistent

[[Page 31862]]

throughout the study. Calves were observed three times and feeding was 
observed four times during the Kraus et al. (2016) study. Sei whales 
were not observed in the MA WEA and nearby waters during the 2010-2017 
Atlantic Marine Assessment Program for Protected Species (AMAPPS) 
shipboard and aerial surveys. However, there were observations during 
the 2016 and 2017 summer surveys that were identified as being either a 
fin or sei whale. A BIA for feeding for sei whales occurs east of the 
Lease Area from May through November (LaBrecque et al. 2015).

Minke Whale

    Minke whales have a cosmopolitan distribution that spans ice-free 
latitudes (Stewart and Leatherwood 1985). The Canadian East Coast stock 
can be found in the area from the western half of the Davis Strait (45 
[deg]W) to the Gulf of Mexico (Waring et al., 2017). This species 
generally occupies waters less than 100 m deep on the continental 
shelf. There appears to be a strong seasonal component to minke whale 
distribution in which spring to fall are times of relatively widespread 
and common occurrence, and when the whales are most abundant in New 
England waters, while during winter the species appears to be largely 
absent (Waring et al., 2017).
    Kraus et al. (2016) observed minke whales in the RI/MA & MA WEAs 
and surrounding areas primarily from May to June. This species 
demonstrated a distinct seasonal habitat usage pattern that was 
consistent throughout the study. Though minke whales were observed in 
spring and summer months in the MA WEA, they were only observed in the 
lease areas in the spring. Minke whales were not observed between 
October and February, but acoustic data indicate the presence of this 
species in the proposed Project Area in winter months. A BIA for 
feeding for minke whales occurs east of the Lease Area from March 
through November (LaBrecque et al., 2015).
    Since January 2017, elevated minke whale strandings have occurred 
along the Atlantic coast from Maine through South Carolina, with 
highest numbers in Massachusetts, Maine, and New York. Partial or full 
necropsy examinations have been conducted on more than 60 percent of 
the 79 known cases. Preliminary findings in several of the whales have 
shown evidence of human interactions or infectious disease. These 
findings are not consistent across all of the whales examined, so more 
research is needed. More information is available at: https://www.fisheries.noaa.gov/national/marine-life-distress/2017-2019-minke-whale-unusual-mortality-event-along-atlantic-coast.

Sperm Whale

    The distribution of the sperm whale in the U.S. Exclusive Economic 
Zone (EEZ) occurs on the continental shelf edge, over the continental 
slope, and into mid-ocean regions (Waring et al. 2015). The basic 
social unit of the sperm whale appears to be the mixed school of adult 
females plus their calves and some juveniles of both sexes, normally 
numbering 20-40 animals in all. Sperm whales are somewhat migratory; 
however, their migrations are not as specific as seen in most of the 
baleen whale species. In the North Atlantic, there appears to be a 
general shift northward during the summer, but there is no clear 
migration in some temperate areas (Rice 1989). In summer, the 
distribution of sperm whales includes the area east and north of 
Georges Bank and into the Northeast Channel region, as well as the 
continental shelf (inshore of the 100-m isobath) south of New England. 
In the fall, sperm whale occurrence south of New England on the 
continental shelf is at its highest level, and there remains a 
continental shelf edge occurrence in the mid-Atlantic bight. In winter, 
sperm whales are concentrated east and northeast of Cape Hatteras. 
Their distribution is typically associated with waters over the 
continental shelf break and the continental slope and into deeper 
waters (Whitehead et al. 1991). Sperm whale concentrations near drop-
offs and areas with strong currents and steep topography are correlated 
with high productivity. These whales occur almost exclusively found at 
the shelf break, regardless of season.
    Kraus et al. (2016) observed sperm whales four times in the RI/MA & 
MA WEAs during the summer and fall from 2011 to 2015. Sperm whales, 
traveling singly or in groups of three or four, were observed three 
times in August and September of 2012, and once in June of 2015.

Long-Finned Pilot Whale

    Long-finned pilot whales are found from North Carolina and north to 
Iceland, Greenland and the Barents Sea (Waring et al., 2016). They are 
generally found along the edge of the continental shelf (a depth of 330 
to 3,300 feet (100 to 1,000 meters)), choosing areas of high relief or 
submerged banks in cold or temperate shoreline waters. In the western 
North Atlantic, long-finned pilot whales are pelagic, occurring in 
especially high densities in winter and spring over the continental 
slope, then moving inshore and onto the shelf in summer and autumn 
following squid and mackerel populations (Reeves et al. 2002). They 
frequently travel into the central and northern Georges Bank, Great 
South Channel, and Gulf of Maine areas during the late spring and 
remain through early fall (May and October) (Payne and Heinemann 1993).
    Note that long-finned and short-finned pilot whales overlap 
spatially along the mid-Atlantic shelf break between New Jersey and the 
southern flank of Georges Bank (Payne and Heinemann 1993, Hayes et al. 
2017) Long-finned pilot whales have occasionally been observed stranded 
as far south as South Carolina, and short-finned pilot whale have 
stranded as far north as Massachusetts (Hayes et al. 2017). The 
latitudinal ranges of the two species therefore remain uncertain. 
However, south of Cape Hatteras, most pilot whale sightings are 
expected to be short-finned pilot whales, while north of approximately 
42[deg] N, most pilot whale sightings are expected to be long-finned 
pilot whales (Hayes et al. 2017). Based on the distributions described 
in Hayes et al. (2017), pilot whale sightings in the Project Area would 
most likely be long-finned pilot whales.
    Kraus et al. (2016) observed pilot whales infrequently in the RI/MA 
& MA WEAs and surrounding areas. Effort-weighted average sighting rates 
for pilot whales could not be calculated. No pilot whales were observed 
during the fall or winter, and these species were only observed 11 
times in the spring and three times in the summer.

Atlantic White-Sided Dolphin

    White-sided dolphins are found in cold temperate and sub-polar 
waters of the North Atlantic, primarily in continental shelf waters to 
the 100-m depth contour from central West Greenland to North Carolina 
(Waring et al., 2017). The Gulf of Maine stock is most common in 
continental shelf waters from Hudson Canyon to Georges Bank, and in the 
Gulf of Maine and lower Bay of Fundy. Sighting data indicate seasonal 
shifts in distribution (Northridge et al., 1997). During January to 
May, low numbers of white-sided dolphins are found from Georges Bank to 
Jeffreys Ledge (off New Hampshire), with even lower numbers south of 
Georges Bank, as documented by a few strandings collected on beaches of 
Virginia to South Carolina. From June through September, large numbers 
of white-sided dolphins are found from Georges Bank to the lower Bay of 
Fundy. From October to December, white-sided dolphins occur at 
intermediate densities from southern Georges Bank to southern Gulf of 
Maine

[[Page 31863]]

(Payne and Heinemann 1990). Sightings south of Georges Bank, 
particularly around Hudson Canyon, occur year round but at low 
densities.
    Kraus et al. (2016) suggest that Atlantic white-sided dolphins 
occur infrequently in the RI/MA & MA WEAs and surrounding areas. 
Effort-weighted average sighting rates for Atlantic white-sided 
dolphins could not be calculated, because this species was only 
observed on eight occasions throughout the duration of the study 
(October 2011 to June 2015). No Atlantic white-sided dolphins were 
observed during the winter months, and this species was only sighted 
twice in the fall and three times in the spring and summer.

Common Dolphin

    The common dolphin is one of the most abundant and widely 
distributed cetaceans, occurring in warm temperate and tropical regions 
worldwide from about 60[deg] N to 50[deg] S (Perrin 2018). These 
dolphins occur in groups of hundreds or thousands of individuals and 
often associate with pilot whales or other dolphin species (Perrin 
2018). Until recently, short-beaked and long-beaked common dolphins 
were thought to be separate species but evidence now suggests that this 
character distinction is based on ecology rather than genetics (Perrin 
2018) and the Committee on Taxonomy now recognizes a single species 
with three subspecies of common dolphin. The common dolphins occurring 
in the Project Area are expected to be short-beaked common dolphins 
(Delphinus delphis delphis; Perrin 2018) and would belong to the 
Western North Atlantic stock (Hayes et al., 2018).
    In the North Atlantic, short-beaked common dolphins are commonly 
found over the continental shelf between the 100-m and 2,000-m isobaths 
and over prominent underwater topography and east to the mid-Atlantic 
Ridge (Waring et al., 2016). This species is found between Cape 
Hatteras and Georges Bank from mid-January to May, although they 
migrate onto the northeast edge of Georges Bank in the fall where large 
aggregations occur (Kenney and Vigness-Raposa 2009), where large 
aggregations occur on Georges Bank in fall (Waring et al. 2007).
    Kraus et al. (2016) suggested that short-beaked common dolphins 
occur year-round in the RI/MA & MA WEAs and surrounding areas. Short-
beaked common dolphins were the most frequently observed small cetacean 
species within the Kraus et al. (2016) study area. Short-beaked common 
dolphins were observed in the RI/MA & MA WEAs in all seasons but were 
most frequently observed during the summer months, with peak sightings 
in June and August. Short-beaked common dolphins were observed in the 
MA WEA and nearby waters during all seasons of the 2010-2017 AMAPPS 
surveys.

Bottlenose Dolphin

    There are two distinct bottlenose dolphin ecotypes in the western 
North Atlantic: the coastal and offshore forms (Waring et al., 2015). 
The migratory coastal morphotype resides in waters typically less than 
65.6 ft (20 m) deep, along the inner continental shelf (within 7.5 km 
(4.6 miles) of shore), around islands, and is continuously distributed 
south of Long Island, New York into the Gulf of Mexico. This migratory 
coastal population is subdivided into 7 stocks based largely upon 
spatial distribution (Waring et al. 2015). Generally, the offshore 
migratory morphotype is found exclusively seaward of 34 km (21 miles) 
and in waters deeper than 34 m (111.5 feet). This morphotype is most 
expected in waters north of Long Island, New York (Waring et al. 2017; 
Hayes et al. 2017; 2018). Bottlenose dolphins encountered in the 
Project Area would likely belong to the Western North Atlantic Offshore 
stock (Hayes et al. 2018). It is possible that a few animals could be 
from the Northern Migratory Coastal stock, but they generally do not 
range farther north than New Jersey.
    Kraus et al. (2016) observed common bottlenose dolphins during all 
seasons within the RI/MA & MA WEAs. Common bottlenose dolphins were the 
second most commonly observed small cetacean species and exhibited 
little seasonal variability in abundance. Common bottlenose dolphins 
were observed in the MA WEA and nearby waters during spring, summer, 
and fall of the 2010-2017 AMAPPS surveys.

Risso's Dolphins

    Risso's dolphins are distributed worldwide in tropical and 
temperate seas (Jefferson et al., 2008, 2014), and in the Northwest 
Atlantic occur from Florida to eastern Newfoundland (Leatherwood et al. 
1976; Baird and Stacey 1991). Off the northeastern U.S. coast, Risso's 
dolphins are distributed along the continental shelf edge from Cape 
Hatteras northward to Georges Bank during spring, summer, and autumn 
(CETAP 1982; Payne et al., 1984). In winter, the range is in the mid-
Atlantic Bight and extends outward into oceanic waters (Payne et al., 
1984).
    Risso's dolphins appear to prefer steep sections of the continental 
shelf edge and deep offshore waters 100-1,000 m deep (Hartman 2018). 
They are deep divers, feeding primarily on deep mesopelagic cephalopods 
such as squid, octopus, and cuttlefish, and likely forage at night 
(Hartman 2018).
    Kraus et al. (2016) results suggest that Risso's dolphins occur 
infrequently in the RI/MA & MA WEAs and surrounding areas. Risso's 
dolphins were observed in the MA WEA and nearby waters during spring 
and summer of the 2010-2017 AMAPPS surveys.

Harbor Porpoise

    The harbor porpoise inhabits cool temperate to subarctic waters of 
the Northern Hemisphere, generally within shallow coastal waters of the 
continental shelf but occasionally travel over deeper, offshore waters 
(Jefferson et al., 2008). They are usually seen in small groups of one 
to three but occasionally form much larger groups (Bj[oslash]rge and 
Tolley 2018).
    There are likely four populations in the western North Atlantic: 
Gulf of Maine/Bay of Fundy, Gulf of St. Lawrence, Newfoundland, and 
Greenland (Gaskin 1984, 1992; Hayes et al., 2019). In the Project Area, 
only the Gulf of Maine/Bay of Fundy stock may be present. This stock is 
found in U.S. and Canadian Atlantic waters and is concentrated in the 
northern Gulf of Maine and southern Bay of Fundy region, generally in 
waters less than 150 m deep (Waring et al., 2017). During fall 
(October-December) and spring (April-June) harbor porpoises are widely 
dispersed from New Jersey to Maine. During winter (January to March), 
intermediate densities of harbor porpoises can be found in waters off 
New Jersey to North Carolina, and lower densities are found in waters 
off New York to New Brunswick, Canada. They are seen from the coastline 
to deep waters (>1800 m; Westgate et al. 1998), although the majority 
of the population is found over the continental shelf (Waring et al., 
2017).
    Kraus et al. (2016) indicate that harbor porpoises occur within the 
RI/MA & MA WEAs in fall, winter, and spring. Harbor porpoises were 
observed in groups ranging in size from three to 15 individuals and 
were primarily observed in the Kraus et al. (2016) study area from 
November through May, with very few sightings during June through 
September. Harbor porpoises were observed in the MA WEA and nearby 
waters during spring and fall of the 2010-2017 AMAPPS surveys.

Harbor Seal

    The harbor seal has a wide distribution throughout coastal waters 
between 30[deg] N and ~80[deg] N (Teilmann and Galatius 2018). Harbor 
seals are

[[Page 31864]]

year-round inhabitants of the coastal waters of eastern Canada and 
Maine (Katona et al. 1993), and occur seasonally along the coasts from 
southern New England to New Jersey from September through late May 
(Barlas 1999; Katona et al., 1993; Schneider and Payne 1983; Schroeder 
2000). A northward movement from southern New England to Maine and 
eastern Canada occurs prior to the pupping season, which takes place 
from mid-May through June (Kenney 1994; Richardson 1976; Whitman and 
Payne 1990; Wilson 1978). Harbor seals are generally present in the 
Project Area seasonally, from September through May (Hayes et al., 
2019).
    Kraus et al. (2016) observed harbor seals in the RI/MA and MA WEAs 
and surrounding areas during the 2011-2015 NLPSC aerial survey, but 
this survey was designed to target large cetaceans so locations and 
numbers of seal observations were not included in the study report. 
Harbor seals have five major haulout sites in and near the RI/MA and MA 
WEAs: Monomoy Island, the northwestern side of Nantucket Island, Nomans 
Land, the north side of Gosnold Island, and the southeastern side of 
Naushon Island (Payne and Selzer 1989). Harbor seals were observed in 
the MA WEA and nearby waters during spring, summer, and fall of the 
2010-2017 AMAPPS surveys.

Gray Seal

    Gray seals are found throughout the temperate and subarctic waters 
of the North Atlantic (King 1983). In the northwestern Atlantic, they 
occur from Labrador sound to Massachusetts (King 1983). Gray seals 
often haul out on remote, exposed islands, shoals, and unstable 
sandbars (Jefferson et al., 2008). Though they spend most of their time 
in coastal waters, gray seals can dive to depths of 300 m (984 ft) and 
frequently forage on the outer continental shelf (Jefferson et al., 
2008).
    Gray seals in the Project Area belong to the western North Atlantic 
stock. The range for this stock is thought to be from New Jersey to 
Labrador. Current population trends show that gray seal abundance is 
likely increasing in the U.S. Atlantic EEZ (Waring et al., 2017). 
Although the rate of increase is unknown, surveys conducted since their 
arrival in the 1980s indicate a steady increase in abundance in both 
Maine and Massachusetts (Waring et al., 2017). It is believed that 
recolonization by Canadian gray seals is the source of the U.S. 
population (Waring et al., 2017). In U.S. waters, gray seals currently 
pup at four established colonies from late December to mid-February: 
Muskeget and Monomoy Islands in Massachusetts, and Green and Seal 
Islands in Maine (Hayes et al., 2019). Pupping was also observed in the 
early 1980s on small islands in Nantucket-Vineyard Sound and since 
2010, pupping has been documented at Nomans Island in Massachusetts 
(Hayes et al., 2019). The distributions of individuals from different 
breeding colonies overlap outside of the breeding season. Gray seals 
may be present in the Project Area year-round (Hayes et al., 2018).
    Since July 2018, elevated numbers of harbor seal and gray seal 
mortalities have occurred across Maine, New Hampshire and 
Massachusetts. This event has been declared a UME. Additionally, seals 
showing clinical signs of stranding have occurred as far south as 
Virginia, although not in elevated numbers. Therefore the UME 
investigation now encompasses all seal strandings from Maine to 
Virginia. Between July 1, 2018 and March 13, 2020, a total of 3,152 
seal strandings have been recorded as part of this designated Northeast 
Pinniped UME. Based on tests conducted so far, the main pathogen found 
in the seals is phocine distemper virus. Additional testing to identify 
other factors that may be involved in this UME are underway. More 
information is available at: https://www.fisheries.noaa.gov/new-england-mid-atlantic/marine-life-distress/2018-2020-pinniped-unusual-mortality-event-along.

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Current data indicate that not all marine 
mammal species have equal hearing capabilities (e.g., Richardson et 
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect 
this, Southall et al. (2007) recommended that marine mammals be divided 
into functional hearing groups based on directly measured or estimated 
hearing ranges on the basis of available behavioral response data, 
audiograms derived using auditory evoked potential techniques, 
anatomical modeling, and other data. Note that no direct measurements 
of hearing ability have been successfully completed for mysticetes 
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibel (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-frequency cetaceans where the 
lower bound was deemed to be biologically implausible and the lower 
bound from Southall et al. (2007) retained. Marine mammal hearing 
groups and their associated hearing ranges are provided in Table 4.

           Table 4--Marine Mammal Hearing Groups (NMFS, 2018)
------------------------------------------------------------------------
             Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen    7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans            150 Hz to 160 kHz.
 (dolphins, toothed whales, beaked
 whales, bottlenose whales).
High-frequency (HF) cetaceans (true     275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 cephalorhynchid, Lagenorhynchus
 cruciger & L. australis).
Phocid pinnipeds (PW) (underwater)      50 Hz to 86 kHz.
 (true seals).
Otariid pinnipeds (OW) (underwater)     60 Hz to 39 kHz.
 (sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al. 2007) and PW pinniped (approximation).

    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids,

[[Page 31865]]

especially in the higher frequency range (Hemil[auml] et al., 2006; 
Kastelein et al., 2009; Reichmuth and Holt, 2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information. 
Fourteen marine mammal species (12 cetacean and two pinniped (both 
phocid) species) have the reasonable potential to co-occur with the 
proposed survey activities. Of the cetacean species that may be 
present, six are classified as low-frequency cetaceans (i.e., all 
mysticete species), five are classified as mid-frequency cetaceans 
(i.e., all delphinid and ziphiid species and the sperm whale), and one 
is classified as high-frequency cetaceans (i.e., harbor porpoise).

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section includes a summary and discussion of the ways that 
components of the specified activity may impact marine mammals and 
their habitat. The Estimated Take by Incidental Harassment section 
later in this document includes a quantitative analysis of the number 
of individuals that are expected to be taken by this activity. The 
Negligible Impact Analysis and Determination section considers the 
content of this section, the Estimated Take by Incidental Harassment 
section, and the Proposed Mitigation section, to draw conclusions 
regarding the likely impacts of these activities on the reproductive 
success or survivorship of individuals and how those impacts on 
individuals are likely to impact marine mammal species or stocks.

Description of Sound Sources

    This section contains a brief technical background on sound, on the 
characteristics of certain sound types, and on metrics used in this 
proposal inasmuch as the information is relevant to the specified 
activity and to a discussion of the potential effects of the specified 
activity on marine mammals found later in this document. For general 
information on sound and its interaction with the marine environment, 
please see, e.g., Au and Hastings (2008); Richardson et al. (1995).
    Sound travels in waves, the basic components of which are 
frequency, wavelength, velocity, and amplitude. Frequency is the number 
of pressure waves that pass by a reference point per unit of time and 
is measured in hertz (Hz) or cycles per second. Wavelength is the 
distance between two peaks or corresponding points of a sound wave 
(length of one cycle). Higher frequency sounds have shorter wavelengths 
than lower frequency sounds, and typically attenuate (decrease) more 
rapidly, except in certain cases in shallower water. Amplitude is the 
height of the sound pressure wave or the ``loudness'' of a sound and is 
typically described using the relative unit of the decibel (dB). A 
sound pressure level (SPL) in dB is described as the ratio between a 
measured pressure and a reference pressure (for underwater sound, this 
is 1 microPascal ([mu]Pa)), and is a logarithmic unit that accounts for 
large variations in amplitude; therefore, a relatively small change in 
dB corresponds to large changes in sound pressure. The source level 
(SL) represents the SPL referenced at a distance of 1 m from the source 
(referenced to 1 [mu]Pa), while the received level is the SPL at the 
listener's position (referenced to 1 [mu]Pa).
    Root mean square (rms) is the quadratic mean sound pressure over 
the duration of an impulse. Root mean square is calculated by squaring 
all of the sound amplitudes, averaging the squares, and then taking the 
square root of the average. Root mean square accounts for both positive 
and negative values; squaring the pressures makes all values positive 
so that they may be accounted for in the summation of pressure levels 
(Hastings and Popper, 2005). This measurement is often used in the 
context of discussing behavioral effects, in part because behavioral 
effects, which often result from auditory cues, may be better expressed 
through averaged units than by peak pressures.
    Sound exposure level (SEL; represented as dB re 1 [mu]Pa\2\-s) 
represents the total energy in a stated frequency band over a stated 
time interval or event, and considers both intensity and duration of 
exposure. The per-pulse SEL is calculated over the time window 
containing the entire pulse (i.e., 100 percent of the acoustic energy). 
SEL is a cumulative metric; it can be accumulated over a single pulse, 
or calculated over periods containing multiple pulses. Cumulative SEL 
represents the total energy accumulated by a receiver over a defined 
time window or during an event. Peak sound pressure (also referred to 
as zero-to-peak sound pressure or 0-pk) is the maximum instantaneous 
sound pressure measurable in the water at a specified distance from the 
source, and is represented in the same units as the rms sound pressure.
    When underwater objects vibrate or activity occurs, sound-pressure 
waves are created. These waves alternately compress and decompress the 
water as the sound wave travels. Underwater sound waves radiate in a 
manner similar to ripples on the surface of a pond and may be either 
directed in a beam or beams or may radiate in all directions 
(omnidirectional sources). The compressions and decompressions 
associated with sound waves are detected as changes in pressure by 
aquatic life and man-made sound receptors such as hydrophones.
    Even in the absence of sound from the specified activity, the 
underwater environment is typically loud due to ambient sound, which is 
defined as environmental background sound levels lacking a single 
source or point (Richardson et al., 1995). The sound level of a region 
is defined by the total acoustical energy being generated by known and 
unknown sources. These sources may include physical (e.g., wind and 
waves, earthquakes, ice, atmospheric sound), biological (e.g., sounds 
produced by marine mammals, fish, and invertebrates), and anthropogenic 
(e.g., vessels, dredging, construction) sound. A number of sources 
contribute to ambient sound, including wind and waves, which are a main 
source of naturally occurring ambient sound for frequencies between 200 
hertz (Hz) and 50 kilohertz (kHz) (Mitson, 1995). In general, ambient 
sound levels tend to increase with increasing wind speed and wave 
height. Precipitation can become an important component of total sound 
at frequencies above 500 Hz, and possibly down to 100 Hz during quiet 
times. Marine mammals can contribute significantly to ambient sound 
levels, as can some fish and snapping shrimp. The frequency band for 
biological contributions is from approximately 12 Hz to over 100 kHz. 
Sources of ambient sound related to human activity include 
transportation (surface vessels), dredging and construction, oil and 
gas drilling and production, geophysical surveys, sonar, and 
explosions. Vessel noise typically dominates the total ambient sound 
for frequencies between 20 and 300 Hz. In general, the frequencies of 
anthropogenic sounds are below 1 kHz and, if higher frequency sound 
levels are created, they attenuate rapidly.
    The sum of the various natural and anthropogenic sound sources that 
comprise ambient sound at any given location and time depends not only 
on the source levels (as determined by current weather conditions and 
levels of biological and human activity) but also on the ability of 
sound to propagate through the environment. In turn, sound propagation 
is dependent on the spatially and temporally varying properties of the 
water column and sea floor, and is frequency-dependent. As a

[[Page 31866]]

result of the dependence on a large number of varying factors, ambient 
sound levels can be expected to vary widely over both coarse and fine 
spatial and temporal scales. Sound levels at a given frequency and 
location can vary by 10-20 dB from day to day (Richardson et al., 
1995). The result is that, depending on the source type and its 
intensity, sound from the specified activity may be a negligible 
addition to the local environment or could form a distinctive signal 
that may affect marine mammals.
    Sounds are often considered to fall into one of two general types: 
Pulsed and non-pulsed. The distinction between these two sound types is 
important because they have differing potential to cause physical 
effects, particularly with regard to hearing (e.g., Ward, 1997 in 
Southall et al., 2007). Please see Southall et al. (2007) for an in-
depth discussion of these concepts. The distinction between these two 
sound types is not always obvious, as certain signals share properties 
of both pulsed and non-pulsed sounds. A signal near a source could be 
categorized as a pulse, but due to propagation effects as it moves 
farther from the source, the signal duration becomes longer (e.g., 
Greene and Richardson, 1988).
    Pulsed sound sources (e.g., airguns, explosions, gunshots, sonic 
booms, impact pile driving) produce signals that are brief (typically 
considered to be less than one second), broadband, atonal transients 
(ANSI, 1986, 2005; Harris, 1998; NIOSH, 1998; ISO, 2003) and occur 
either as isolated events or repeated in some succession. Pulsed sounds 
are all characterized by a relatively rapid rise from ambient pressure 
to a maximal pressure value followed by a rapid decay period that may 
include a period of diminishing, oscillating maximal and minimal 
pressures, and generally have an increased capacity to induce physical 
injury as compared with sounds that lack these features.
    Non-pulsed sounds can be tonal, narrowband, or broadband, brief or 
prolonged, and may be either continuous or intermittent (ANSI, 1995; 
NIOSH, 1998). Some of these non-pulsed sounds can be transient signals 
of short duration but without the essential properties of pulses (e.g., 
rapid rise time). Examples of non-pulsed sounds include those produced 
by vessels, aircraft, machinery operations such as drilling or 
dredging, vibratory pile driving, and active sonar systems. The 
duration of such sounds, as received at a distance, can be greatly 
extended in a highly reverberant environment.

Potential Effects of Underwater Sound

    For study-specific citations, please see that work. Anthropogenic 
sounds cover a broad range of frequencies and sound levels and can have 
a range of highly variable impacts on marine life, from none or minor 
to potentially severe responses, depending on received levels, duration 
of exposure, behavioral context, and various other factors. The 
potential effects of underwater sound from active acoustic sources can 
potentially result in one or more of the following: temporary or 
permanent hearing impairment, non-auditory physical or physiological 
effects, behavioral disturbance, stress, and masking (Richardson et 
al., 1995; Gordon et al., 2004; Nowacek et al., 2007; Southall et al., 
2007; G[ouml]tz et al., 2009). The degree of effect is intrinsically 
related to the signal characteristics, received level, distance from 
the source, and duration of the sound exposure. In general, sudden, 
high level sounds can cause hearing loss, as can longer exposures to 
lower level sounds. Temporary or permanent loss of hearing will occur 
almost exclusively for noise within an animal's hearing range.
    Richardson et al. (1995) described zones of increasing intensity of 
effect that might be expected to occur, in relation to distance from a 
source and assuming that the signal is within an animal's hearing 
range. First is the area within which the acoustic signal would be 
audible (potentially perceived) to the animal but not strong enough to 
elicit any overt behavioral or physiological response. The next zone 
corresponds with the area where the signal is audible to the animal and 
of sufficient intensity to elicit behavioral or physiological 
responsiveness. Third is a zone within which, for signals of high 
intensity, the received level is sufficient to potentially cause 
discomfort or tissue damage to auditory or other systems. Overlaying 
these zones to a certain extent is the area within which masking (i.e., 
when a sound interferes with or masks the ability of an animal to 
detect a signal of interest that is above the absolute hearing 
threshold) may occur; the masking zone may be highly variable in size.
    We describe the more severe effects (i.e., certain non-auditory 
physical or physiological effects) only briefly as we do not expect 
that there is a reasonable likelihood that HRG surveys may result in 
such effects (see below for further discussion). Potential effects from 
impulsive sound sources can range in severity from effects such as 
behavioral disturbance or tactile perception to physical discomfort, 
slight injury of the internal organs and the auditory system, or 
mortality (Yelverton et al., 1973). Non-auditory physiological effects 
or injuries that theoretically might occur in marine mammals exposed to 
high level underwater sound or as a secondary effect of extreme 
behavioral reactions (e.g., change in dive profile as a result of an 
avoidance reaction) caused by exposure to sound include neurological 
effects, bubble formation, resonance effects, and other types of organ 
or tissue damage (Cox et al., 2006; Southall et al., 2007; Zimmer and 
Tyack, 2007; Tal et al., 2015). The activities considered here do not 
involve the use of devices such as explosives or mid-frequency tactical 
sonar that are associated with these types of effects.
    Threshold Shift--Note that, in the following discussion, we refer 
in many cases to a review article concerning studies of noise-induced 
hearing loss conducted from 1996-2015 (i.e., Finneran, 2015). Marine 
mammals exposed to high-intensity sound, or to lower-intensity sound 
for prolonged periods, can experience hearing threshold shift (TS), 
which is the loss of hearing sensitivity at certain frequency ranges 
(Finneran, 2015). TS can be permanent (PTS), in which case the loss of 
hearing sensitivity is not fully recoverable, or temporary (TTS), in 
which case the animal's hearing threshold would recover over time 
(Southall et al., 2007). Repeated sound exposure that leads to TTS 
could cause PTS. In severe cases of PTS, there can be total or partial 
deafness, while in most cases the animal has an impaired ability to 
hear sounds in specific frequency ranges (Kryter, 1985).
    When PTS occurs, there is physical damage to the sound receptors in 
the ear (i.e., tissue damage), whereas TTS represents primarily tissue 
fatigue and is reversible (Southall et al., 2007). In addition, other 
investigators have suggested that TTS is within the normal bounds of 
physiological variability and tolerance and does not represent physical 
injury (e.g., Ward, 1997). Therefore, NMFS does not consider TTS to 
constitute auditory injury.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals, and there is no PTS data for cetaceans, but such 
relationships are assumed to be similar to those in humans and other 
terrestrial mammals. PTS typically occurs at exposure levels at least 
several decibels above (a 40-dB threshold shift approximates PTS onset; 
e.g., Kryter et al., 1966; Miller, 1974) that inducing mild TTS (a 6-dB 
threshold shift approximates TTS onset; e.g., Southall

[[Page 31867]]

et al. 2007). Based on data from terrestrial mammals, a precautionary 
assumption is that the PTS thresholds for impulse sounds (such as 
impact pile driving pulses as received close to the source) are at 
least 6 dB higher than the TTS threshold on a peak-pressure basis and 
PTS cumulative sound exposure level thresholds are 15 to 20 dB higher 
than TTS cumulative sound exposure level thresholds (Southall et al., 
2007). Given the higher level of sound or longer exposure duration 
necessary to cause PTS as compared with TTS, it is considerably less 
likely that PTS could occur.
    TTS is the mildest form of hearing impairment that can occur during 
exposure to sound (Kryter, 1985). While experiencing TTS, the hearing 
threshold rises, and a sound must be at a higher level in order to be 
heard. In terrestrial and marine mammals, TTS can last from minutes or 
hours to days (in cases of strong TTS). In many cases, hearing 
sensitivity recovers rapidly after exposure to the sound ends. Few data 
on sound levels and durations necessary to elicit mild TTS have been 
obtained for marine mammals.
    Marine mammal hearing plays a critical role in communication with 
conspecifics, and interpretation of environmental cues for purposes 
such as predator avoidance and prey capture. Depending on the degree 
(elevation of threshold in dB), duration (i.e., recovery time), and 
frequency range of TTS, and the context in which it is experienced, TTS 
can have effects on marine mammals ranging from discountable to 
serious. For example, a marine mammal may be able to readily compensate 
for a brief, relatively small amount of TTS in a non-critical frequency 
range that occurs during a time where ambient noise is lower and there 
are not as many competing sounds present. Alternatively, a larger 
amount and longer duration of TTS sustained during time when 
communication is critical for successful mother/calf interactions could 
have more serious impacts.
    Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin, beluga whale (Delphinapterus leucas), harbor 
porpoise, and Yangtze finless porpoise (Neophocoena asiaeorientalis)) 
and three species of pinnipeds (northern elephant seal (Mirounga 
angustirostris), harbor seal, and California sea lion (Zalophus 
californianus)) exposed to a limited number of sound sources (i.e., 
mostly tones and octave-band noise) in laboratory settings (Finneran, 
2015). TTS was not observed in trained spotted (Phoca largha) and 
ringed (Pusa hispida) seals exposed to impulsive noise at levels 
matching previous predictions of TTS onset (Reichmuth et al., 2016). In 
general, harbor seals and harbor porpoises have a lower TTS onset than 
other measured pinniped or cetacean species (Finneran, 2015). 
Additionally, the existing marine mammal TTS data come from a limited 
number of individuals within these species. There are no data available 
on noise-induced hearing loss for mysticetes. For summaries of data on 
TTS in marine mammals or for further discussion of TTS onset 
thresholds, please see Southall et al. (2007), Finneran and Jenkins 
(2012), Finneran (2015), and NMFS (2018).
    Animals in the Project Area during the proposed survey are unlikely 
to incur TTS due to the characteristics of the sound sources, which 
include relatively low source levels and generally very short pulses 
and duration of the sound. Even for high-frequency cetacean species 
(e.g., harbor porpoises), which may have increased sensitivity to TTS 
(Lucke et al., 2009; Kastelein et al., 2012b), individuals would have 
to make a very close approach and also remain very close to vessels 
operating these sources in order to receive multiple exposures at 
relatively high levels, as would be necessary to cause TTS. 
Intermittent exposures--as would occur due to the brief, transient 
signals produced by these sources--require a higher cumulative SEL to 
induce TTS than would continuous exposures of the same duration (i.e., 
intermittent exposure results in lower levels of TTS) (Mooney et al., 
2009a; Finneran et al., 2010). Moreover, most marine mammals would more 
likely avoid a loud sound source rather than swim in such close 
proximity as to result in TTS. Kremser et al. (2005) noted that the 
probability of a cetacean swimming through the area of exposure when a 
sub-bottom profiler emits a pulse is small--because if the animal was 
in the area, it would have to pass the transducer at close range in 
order to be subjected to sound levels that could cause TTS and would 
likely exhibit avoidance behavior to the area near the transducer 
rather than swim through at such a close range. Further, the restricted 
beam shape of the majority of the geophysical survey equipment proposed 
for use makes it unlikely that an animal would be exposed more than 
briefly during the passage of the vessel.
    Behavioral Effects--Behavioral disturbance may include a variety of 
effects, including subtle changes in behavior (e.g., minor or brief 
avoidance of an area or changes in vocalizations), more conspicuous 
changes in similar behavioral activities, and more sustained and/or 
potentially severe reactions, such as displacement from or abandonment 
of high-quality habitat. Behavioral responses to sound are highly 
variable and context-specific and any reactions depend on numerous 
intrinsic and extrinsic factors (e.g., species, state of maturity, 
experience, current activity, reproductive state, auditory sensitivity, 
time of day), as well as the interplay between factors (e.g., 
Richardson et al., 1995; Wartzok et al., 2003; Southall et al., 2007; 
Weilgart, 2007; Archer et al., 2010). Behavioral reactions can vary not 
only among individuals but also within an individual, depending on 
previous experience with a sound source, context, and numerous other 
factors (Ellison et al., 2012), and can vary depending on 
characteristics associated with the sound source (e.g., whether it is 
moving or stationary, number of sources, distance from the source). 
Please see Appendices B-C of Southall et al. (2007) for a review of 
studies involving marine mammal behavioral responses to sound.
    Habituation can occur when an animal's response to a stimulus wanes 
with repeated exposure, usually in the absence of unpleasant associated 
events (Wartzok et al., 2003). Animals are most likely to habituate to 
sounds that are predictable and unvarying. It is important to note that 
habituation is appropriately considered as a ``progressive reduction in 
response to stimuli that are perceived as neither aversive nor 
beneficial,'' rather than as, more generally, moderation in response to 
human disturbance (Bejder et al., 2009). The opposite process is 
sensitization, when an unpleasant experience leads to subsequent 
responses, often in the form of avoidance, at a lower level of 
exposure. As noted, behavioral state may affect the type of response. 
For example, animals that are resting may show greater behavioral 
change in response to disturbing sound levels than animals that are 
highly motivated to remain in an area for feeding (Richardson et al., 
1995; NRC, 2003; Wartzok et al., 2003). Controlled experiments with 
captive marine mammals have showed pronounced behavioral reactions, 
including avoidance of loud sound sources (Ridgway et al., 1997; 
Finneran et al., 2003). Observed responses of wild marine mammals to 
loud pulsed sound sources (typically airguns or acoustic harassment 
devices) have been varied but often consist of avoidance behavior or 
other behavioral changes suggesting discomfort (Morton and Symonds, 
2002; see also Richardson et al., 1995;

[[Page 31868]]

Nowacek et al., 2007). However, many delphinids approach low-frequency 
airgun source vessels with no apparent discomfort or obvious behavioral 
change (e.g., Barkaszi et al., 2012), indicating the importance of 
frequency output in relation to the species' hearing sensitivity.
    Available studies show wide variation in response to underwater 
sound; therefore, it is difficult to predict specifically how any given 
sound in a particular instance might affect marine mammals perceiving 
the signal. If a marine mammal does react briefly to an underwater 
sound by changing its behavior or moving a small distance, the impacts 
of the change are unlikely to be significant to the individual, let 
alone the stock or population. However, if a sound source displaces 
marine mammals from an important feeding or breeding area for a 
prolonged period, impacts on individuals and populations could be 
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC, 
2005). However, there are broad categories of potential response, which 
we describe in greater detail here, that include alteration of dive 
behavior, alteration of foraging behavior, effects to breathing, 
interference with or alteration of vocalization, avoidance, and flight.
    Changes in dive behavior can vary widely and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g., Frankel 
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et 
al.; 2004; Goldbogen et al., 2013a, 2013b). Variations in dive behavior 
may reflect interruptions in biologically significant activities (e.g., 
foraging) or they may be of little biological significance. The impact 
of an alteration to dive behavior resulting from an acoustic exposure 
depends on what the animal is doing at the time of the exposure and the 
type and magnitude of the response.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al., 
2001; Nowacek et al.; 2004; Madsen et al., 2006; Yazvenko et al., 
2007). A determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    Variations in respiration naturally vary with different behaviors 
and alterations to breathing rate as a function of acoustic exposure 
can be expected to co-occur with other behavioral reactions, such as a 
flight response or an alteration in diving. However, respiration rates 
in and of themselves may be representative of annoyance or an acute 
stress response. Various studies have shown that respiration rates may 
either be unaffected or could increase, depending on the species and 
signal characteristics, again highlighting the importance in 
understanding species differences in the tolerance of underwater noise 
when determining the potential for impacts resulting from anthropogenic 
sound exposure (e.g., Kastelein et al., 2001, 2005, 2006; Gailey et 
al., 2007; Gailey et al., 2016).
    Marine mammals vocalize for different purposes and across multiple 
modes, such as whistling, echolocation click production, calling, and 
singing. Changes in vocalization behavior in response to anthropogenic 
noise can occur for any of these modes and may result from a need to 
compete with an increase in background noise or may reflect increased 
vigilance or a startle response. For example, in the presence of 
potentially masking signals, humpback whales and killer whales have 
been observed to increase the length of their songs (Miller et al., 
2000; Fristrup et al., 2003; Foote et al., 2004), while right whales 
have been observed to shift the frequency content of their calls upward 
while reducing the rate of calling in areas of increased anthropogenic 
noise (Parks et al., 2007). In some cases, animals may cease sound 
production during production of aversive signals (Bowles et al., 1994).
    Avoidance is the displacement of an individual from an area or 
migration path as a result of the presence of a sound or other 
stressors, and is one of the most obvious manifestations of disturbance 
in marine mammals (Richardson et al., 1995). For example, gray whales 
are known to change direction--deflecting from customary migratory 
paths--in order to avoid noise from airgun surveys (Malme et al., 
1984). Avoidance may be short-term, with animals returning to the area 
once the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996; 
Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007). 
Longer-term displacement is possible, however, which may lead to 
changes in abundance or distribution patterns of the affected species 
in the affected region if habituation to the presence of the sound does 
not occur (e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann 
et al., 2006).
    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of predators have occurred (Connor and 
Heithaus, 1996). The result of a flight response could range from 
brief, temporary exertion and displacement from the area where the 
signal provokes flight to, in extreme cases, marine mammal strandings 
(Evans and England, 2001). However, it should be noted that response to 
a perceived predator does not necessarily invoke flight (Ford and 
Reeves, 2008), and whether individuals are solitary or in groups may 
influence the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fish and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In 
addition, chronic disturbance can cause population declines through 
reduction of fitness (e.g., decline in body condition) and subsequent 
reduction in reproductive success, survival, or both (e.g., Harrington 
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However, 
Ridgway et al. (2006) reported that increased vigilance in bottlenose 
dolphins exposed to sound over a five-day period did not cause any 
sleep deprivation or stress effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent

[[Page 31869]]

days (Southall et al., 2007). Consequently, a behavioral response 
lasting less than one day and not recurring on subsequent days is not 
considered particularly severe unless it could directly affect 
reproduction or survival (Southall et al., 2007). Note that there is a 
difference between multi-day substantive behavioral reactions and 
multi-day anthropogenic activities. For example, just because an 
activity lasts for multiple days does not necessarily mean that 
individual animals are either exposed to activity-related stressors for 
multiple days or, further, exposed in a manner resulting in sustained 
multi-day substantive behavioral responses.
    We expect that some marine mammals may exhibit behavioral responses 
to the HRG survey activities in the form of avoidance of the area 
during the activity, especially the naturally shy harbor porpoise, 
while others such as delphinids might be attracted to the survey 
activities out of curiosity. However, because the HRG survey equipment 
operates from a moving vessel, and the maximum radius to the Level B 
harassment threshold is relatively small, the area and time that this 
equipment would be affecting a given location is very small. Further, 
once an area has been surveyed, it is not likely that it will be 
surveyed again, thereby reducing the likelihood of repeated impacts 
within the Project Area.
    We have also considered the potential for severe behavioral 
responses such as stranding and associated indirect injury or mortality 
from Mayflower's use of HRG survey equipment. Commenters on previous 
IHAs involving HRG surveys have referenced a 2008 mass stranding of 
approximately 100 melon-headed whales in a Madagascar lagoon system. An 
investigation of the event indicated that use of a high-frequency 
mapping system (12-kHz multibeam echosounder) was the most plausible 
and likely initial behavioral trigger of the event, while providing the 
caveat that there is no unequivocal and easily identifiable single 
cause (Southall et al., 2013). The investigatory panel's conclusion was 
based on (1) very close temporal and spatial association and directed 
movement of the survey with the stranding event; (2) the unusual nature 
of such an event coupled with previously documented apparent behavioral 
sensitivity of the species to other sound types (Southall et al., 2006; 
Brownell et al., 2009); and (3) the fact that all other possible 
factors considered were determined to be unlikely causes. Specifically, 
regarding survey patterns prior to the event and in relation to 
bathymetry, the vessel transited in a north-south direction on the 
shelf break parallel to the shore, ensonifying large areas of deep-
water habitat prior to operating intermittently in a concentrated area 
offshore from the stranding site; this may have trapped the animals 
between the sound source and the shore, thus driving them towards the 
lagoon system. The investigatory panel systematically excluded or 
deemed highly unlikely nearly all potential reasons for these animals 
leaving their typical pelagic habitat for an area extremely atypical 
for the species (i.e., a shallow lagoon system). Notably, this was the 
first time that such a system has been associated with a stranding 
event. The panel also noted several site- and situation-specific 
secondary factors that may have contributed to the avoidance responses 
that led to the eventual entrapment and mortality of the whales. 
Specifically, shoreward-directed surface currents and elevated 
chlorophyll levels in the area preceding the event may have played a 
role (Southall et al., 2013). The report also notes that prior use of a 
similar system in the general area may have sensitized the animals and 
also concluded that, for odontocete cetaceans that hear well in higher 
frequency ranges where ambient noise is typically quite low, high-power 
active sonars operating in this range may be more easily audible and 
have potential effects over larger areas than low frequency systems 
that have more typically been considered in terms of anthropogenic 
noise impacts. It is, however, important to note that the relatively 
lower output frequency, higher output power, and complex nature of the 
system implicated in this event, in context of the other factors noted 
here, likely produced a fairly unusual set of circumstances that 
indicate that such events would likely remain rare and are not 
necessarily relevant to use of lower-power, higher-frequency systems 
more commonly used for HRG survey applications. The risk of similar 
events recurring is likely very low, given the extensive use of active 
acoustic systems used for scientific and navigational purposes 
worldwide on a daily basis and the lack of direct evidence of such 
responses previously reported.
    Stress Responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle, 1950; 
Moberg, 2000). In many cases, an animal's first and sometimes most 
economical (in terms of energetic costs) response is behavioral 
avoidance of the potential stressor. Autonomic nervous system responses 
to stress typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha, 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker, 2000; 
Romano et al., 2002b) and, more rarely, studied in wild populations 
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found 
that noise reduction from reduced ship traffic in the Bay of Fundy was 
associated with decreased stress in North Atlantic right whales. These 
and other studies lead to a reasonable expectation that some marine 
mammals will experience physiological stress responses upon exposure to 
acoustic

[[Page 31870]]

stressors and that it is possible that some of these would be 
classified as ``distress.'' In addition, any animal experiencing TTS 
would likely also experience stress responses (NRC, 2003).
    NMFS does not expect that the generally short-term, intermittent, 
and transitory HRG activities would create conditions of long-term, 
continuous noise and chronic acoustic exposure leading to long-term 
physiological stress responses in marine mammals.
    Auditory Masking--Sound can disrupt behavior through masking, or 
interfering with, an animal's ability to detect, recognize, or 
discriminate between acoustic signals of interest (e.g., those used for 
intraspecific communication and social interactions, prey detection, 
predator avoidance, navigation) (Richardson et al., 1995; Erbe et al., 
2016). Masking occurs when the receipt of a sound is interfered with by 
another coincident sound at similar frequencies and at similar or 
higher intensity, and may occur whether the sound is natural (e.g., 
snapping shrimp, wind, waves, precipitation) or anthropogenic (e.g., 
shipping, sonar, seismic exploration) in origin. The ability of a noise 
source to mask biologically important sounds depends on the 
characteristics of both the noise source and the signal of interest 
(e.g., signal-to-noise ratio, temporal variability, direction), in 
relation to each other and to an animal's hearing abilities (e.g., 
sensitivity, frequency range, critical ratios, frequency 
discrimination, directional discrimination, age or TTS hearing loss), 
and existing ambient noise and propagation conditions.
    Under certain circumstances, marine mammals experiencing 
significant masking could also be impaired from maximizing their 
performance fitness in survival and reproduction. Therefore, when the 
coincident (masking) sound is man-made, it may be considered harassment 
if disrupting behavioral patterns. It is important to distinguish TTS 
and PTS, which persist after the sound exposure, from masking, which 
occurs during the sound exposure. Because masking (without resulting in 
TS) is not associated with abnormal physiological function, it is not 
considered a physiological effect, but rather a potential behavioral 
effect.
    The frequency range of the potentially masking sound is important 
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation 
sounds produced by odontocetes but are more likely to affect detection 
of mysticete communication calls and other potentially important 
natural sounds such as those produced by surf and some prey species. 
The masking of communication signals by anthropogenic noise may be 
considered as a reduction in the communication space of animals (e.g., 
Clark et al., 2009) and may result in energetic or other costs as 
animals change their vocalization behavior (e.g., Miller et al., 2000; 
Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2009; Holt 
et al., 2009). Masking can be reduced in situations where the signal 
and noise come from different directions (Richardson et al., 1995), 
through amplitude modulation of the signal, or through other 
compensatory behaviors (Houser and Moore, 2014). Masking can be tested 
directly in captive species (e.g., Erbe, 2008), but in wild populations 
it must be either modeled or inferred from evidence of masking 
compensation. There are few studies addressing real-world masking 
sounds likely to be experienced by marine mammals in the wild (e.g., 
Branstetter et al., 2013).
    Masking affects both senders and receivers of acoustic signals and 
can potentially have long-term chronic effects on marine mammals at the 
population level as well as at the individual level. Low-frequency 
ambient sound levels have increased by as much as 20 dB (more than 
three times in terms of SPL) in the world's ocean from pre-industrial 
periods, with most of the increase from distant commercial shipping 
(Hildebrand, 2009). All anthropogenic sound sources, but especially 
chronic and lower-frequency signals (e.g., from vessel traffic), 
contribute to elevated ambient sound levels, thus intensifying masking.
    Marine mammal communications would not likely be masked appreciably 
by the HRG equipment given the directionality of the signals (for most 
geophysical survey equipment types proposed for use (Table 1) and the 
brief period when an individual mammal is likely to be within its beam.

Vessel Strike

    Vessel strikes of marine mammals can cause significant wounds, 
which may lead to the death of the animal. An animal at the surface 
could be struck directly by a vessel, a surfacing animal could hit the 
bottom of a vessel, or a vessel's propeller could injure an animal just 
below the surface. The severity of injuries typically depends on the 
size and speed of the vessel (Knowlton and Kraus 2001; Laist et al., 
2001; Vanderlaan and Taggart 2007).
    The most vulnerable marine mammals are those that spend extended 
periods of time at the surface in order to restore oxygen levels within 
their tissues after deep dives (e.g., the sperm whale). In addition, 
some baleen whales, such as the North Atlantic right whale, seem 
generally unresponsive to vessel sound, making them more susceptible to 
vessel collisions (Nowacek et al., 2004). These species are primarily 
large, slow moving whales. Smaller marine mammals (e.g., bottlenose 
dolphin) move quickly through the water column and are often seen 
riding the bow wave of large ships. Marine mammal responses to vessels 
may include avoidance and changes in dive pattern (NRC 2003). An 
examination of all known ship strikes from all shipping sources 
(civilian and military) indicates vessel speed is a principal factor in 
whether a vessel strike results in death (Knowlton and Kraus 2001; 
Laist et al., 2001; Jensen and Silber 2003; Vanderlaan and Taggart 
2007). In assessing records with known vessel speeds, Laist et al. 
(2001) found a direct relationship between the occurrence of a whale 
strike and the speed of the vessel involved in the collision. The 
authors concluded that most deaths occurred when a vessel was traveling 
in excess of 24.1 km/h (14.9 mph; 13 kn). Given the slow vessel speeds 
and predictable course necessary for data acquisition, ship strike is 
unlikely to occur during the geophysical surveys. Marine mammals would 
be able to easily avoid the survey vessel due to the slow vessel speed. 
Further, Mayflower would implement measures (e.g., protected species 
monitoring, vessel speed restrictions and separation distances; see 
Proposed Mitigation) set forth in the BOEM lease to reduce the risk of 
a vessel strike to marine mammal species in the Project Area.

Anticipated Effects on Marine Mammal Habitat

    The proposed activities would not result in permanent impacts to 
habitats used directly by marine mammals, but may have potential minor 
and short-term impacts to food sources such as forage fish. The 
proposed activities could affect acoustic habitat (see masking 
discussion above), but meaningful impacts are unlikely. There are no 
feeding areas, rookeries, or mating grounds known to be biologically 
important to marine mammals within the proposed Project Area with the 
exception of feeding BIAs for right, humpback, fin, and sei whales and 
a migratory BIA for right whales which were described previously. The 
HRG survey equipment will not contact the substrate and does not 
represent a

[[Page 31871]]

source of pollution. Impacts to substrate or from pollution are 
therefore not discussed further.
    Effects to Prey--Sound may affect marine mammals through impacts on 
the abundance, behavior, or distribution of prey species (e.g., 
crustaceans, cephalopods, fish, zooplankton). Marine mammal prey varies 
by species, season, and location and, for some, is not well documented. 
Here, we describe studies regarding the effects of noise on known 
marine mammal prey.
    Fish utilize the soundscape and components of sound in their 
environment to perform important functions such as foraging, predator 
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009). 
Depending on their hearing anatomy and peripheral sensory structures, 
which vary among species, fishes hear sounds using pressure and 
particle motion sensitivity capabilities and detect the motion of 
surrounding water (Fay et al., 2008). The potential effects of noise on 
fishes depends on the overlapping frequency range, distance from the 
sound source, water depth of exposure, and species-specific hearing 
sensitivity, anatomy, and physiology. Key impacts to fishes may include 
behavioral responses, hearing damage, barotrauma (pressure-related 
injuries), and mortality.
    Fish react to sounds which are especially strong and/or 
intermittent low-frequency sounds, and behavioral responses such as 
flight or avoidance are the most likely effects. Short duration, sharp 
sounds can cause overt or subtle changes in fish behavior and local 
distribution. The reaction of fish to noise depends on the 
physiological state of the fish, past exposures, motivation (e.g., 
feeding, spawning, migration), and other environmental factors. 
Hastings and Popper (2005) identified several studies that suggest fish 
may relocate to avoid certain areas of sound energy. Several studies 
have demonstrated that impulse sounds might affect the distribution and 
behavior of some fishes, potentially impacting foraging opportunities 
or increasing energetic costs (e.g., Fewtrell and McCauley, 2012; 
Pearson et al., 1992; Skalski et al., 1992; Santulli et al., 1999; 
Paxton et al., 2017). However, some studies have shown no or slight 
reaction to impulse sounds (e.g., Pena et al., 2013; Wardle et al., 
2001; Jorgenson and Gyselman, 2009; Cott et al., 2012). More commonly, 
though, the impacts of noise on fish are temporary.
    We are not aware of any available literature on impacts to marine 
mammal prey from sound produced by HRG survey equipment. However, as 
the HRG survey equipment introduces noise to the marine environment, 
there is the potential for it to result in avoidance of the area around 
the HRG survey activities on the part of marine mammal prey. The 
duration of fish avoidance of an area after HRG surveys depart the area 
is unknown, but a rapid return to normal recruitment, distribution and 
behavior is anticipated. In general, impacts to marine mammal prey 
species are expected to be minor and temporary due to the expected 
short daily duration of the proposed HRG survey, the fact that the 
proposed survey is mobile rather than stationary, and the relatively 
small areas potentially affected. The areas likely impacted by the 
proposed activities are relatively small compared to the available 
habitat in the Atlantic Ocean. Any behavioral avoidance by fish of the 
disturbed area would still leave significantly large areas of fish and 
marine mammal foraging habitat in the nearby vicinity. Based on the 
information discussed herein, we conclude that impacts of the specified 
activity are not likely to have more than short-term adverse effects on 
any prey habitat or populations of prey species. Because of the 
temporary nature of the disturbance, and the availability of similar 
habitat and resources (e.g., prey species) in the surrounding area, any 
impacts to marine mammal habitat are not expected to result in 
significant or long-term consequences for individual marine mammals, or 
to contribute to adverse impacts on their populations. Effects to 
habitat will not be discussed further in this document.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS' consideration of ``small numbers'' and the negligible impact 
determination.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance, which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes would be by Level B harassment only in the form of 
disruption of behavioral patterns for individual marine mammals 
resulting from exposure to HRG sources. Based on the nature of the 
activity and the anticipated effectiveness of the mitigation measures 
(i.e., exclusion zones and shutdown measures), discussed in detail 
below in Proposed Mitigation section, Level A harassment is neither 
anticipated nor proposed to be authorized.
    As described previously, no mortality is anticipated or proposed to 
be authorized for this activity. Below we describe how the take is 
estimated.
    Generally speaking, we estimate take by considering: (1) Acoustic 
thresholds above which NMFS believes the best available science 
indicates marine mammals will be behaviorally harassed or incur some 
degree of permanent hearing impairment; (2) the area or volume of water 
that will be ensonified above these levels in a day; (3) the density or 
occurrence of marine mammals within these ensonified areas; and, (4) 
and the number of days of activities. We note that while these basic 
factors can contribute to a basic calculation to provide an initial 
prediction of takes, additional information that can qualitatively 
inform take estimates is also sometimes available (e.g., previous 
monitoring results or average group size). Below, we describe the 
factors considered here in more detail and present the proposed take 
estimate.

Acoustic Thresholds

    Using the best available science, NMFS has developed acoustic 
thresholds that identify the received level of underwater sound above 
which exposed marine mammals would be reasonably expected to be 
behaviorally harassed (equated to Level B harassment) or to incur PTS 
of some degree (equated to Level A harassment).
    Level B Harassment for non-explosive sources--Though significantly 
driven by received level, the onset of behavioral disturbance from 
anthropogenic noise exposure is also informed to varying degrees by 
other factors related to the source (e.g., frequency, predictability, 
duty cycle), the environment (e.g., bathymetry), and the receiving 
animals (hearing, motivation, experience, demography, behavioral 
context) and can be difficult to predict (Southall et al., 2007, 
Ellison et al., 2012). Based on what the available science indicates 
and the practical need to use a threshold based on a factor that is 
both predictable and measurable for most activities, NMFS uses a 
generalized acoustic threshold based on received level to estimate the 
onset of behavioral harassment. NMFS predicts that marine mammals are 
likely to be behaviorally

[[Page 31872]]

harassed in a manner we consider Level B harassment when exposed to 
underwater anthropogenic noise above received levels of 160 dB re 1 
[mu]Pa (rms) for impulsive and/or intermittent sources (e.g., impact 
pile driving) and 120 dB rms for continuous sources (e.g., vibratory 
driving). Mayflower's proposed activity includes the use of impulsive 
sources (geophysical survey equipment), and therefore use of the 160 dB 
re 1 [mu]Pa (rms) threshold is applicable.
    Level A harassment for non-explosive sources--NMFS' Technical 
Guidance for Assessing the Effects of Anthropogenic Sound on Marine 
Mammal Hearing (Version 2.0) (Technical Guidance, 2018) identifies dual 
criteria to assess auditory injury (Level A harassment) to five 
different marine mammal groups (based on hearing sensitivity) as a 
result of exposure to noise from two different types of sources 
(impulsive or non-impulsive). The components of Mayflower's proposed 
activity includes the use of impulsive sources.
    Predicted distances to Level A harassment isopleths, which vary 
based on marine mammal functional hearing groups were calculated. The 
updated acoustic thresholds for impulsive sounds (such as HRG survey 
equipment) contained in the Technical Guidance (NMFS, 2018) were 
presented as dual metric acoustic thresholds using both 
SELcum and peak sound pressure level metrics. As dual 
metrics, NMFS considers onset of PTS (Level A harassment) to have 
occurred when either one of the two metrics is exceeded (i.e., metric 
resulting in the largest isopleth). The SELcum metric 
considers both level and duration of exposure, as well as auditory 
weighting functions by marine mammal hearing group.
    These thresholds are provided in Table 5 below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS 2018 Technical Guidance, which may be accessed at: 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                     Table 5--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: L pk,flat: 219 dB;  Cell 2: LE,LF,24h: 199 dB.
                                          L E,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.
----------------------------------------------------------------------------------------------------------------

    NMFS considers the data provided by Crocker and Fratantonio (2016) 
to represent the best available information on source levels associated 
with HRG equipment and therefore recommends that source levels provided 
by Crocker and Fratantonio (2016) be incorporated in the method 
described above to estimate isopleth distances to the Level B 
harassment threshold. In cases when the source level for a specific 
type of HRG equipment is not provided in Crocker and Fratantonio 
(2016), NMFS recommends that either the source levels provided by the 
manufacturer be used, or, in instances where source levels provided by 
the manufacturer are unavailable or unreliable, a proxy from Crocker 
and Fratantonio (2016) be used instead. Table 2 shows the HRG equipment 
types that may be used during the proposed surveys and the sound levels 
associated with those HRG equipment types. Tables 2 and 4 of Appendix B 
in the IHA application shows the literature sources for the sound 
source levels that are shown in Table 2 and that were incorporated into 
the modeling of Level B isopleth distances to the Level B harassment 
threshold.
    Results of modeling using the methodology described above indicated 
that, of the HRG survey equipment planned for use by Mayflower that has 
the potential to result in harassment of marine mammals, sound produced 
by the Geomarine Geo-Spark 400 tip sparker would propagate furthest to 
the Level B harassment threshold (Table 6); therefore, for the purposes 
of the exposure analysis, it was assumed the Geomarine Geo-Spark 400 
tip sparker would be active during the entire duration of the surveys. 
Thus the distance to the isopleth corresponding to the threshold for 
Level B harassment for the Geomarine Geo-Spark 400 tip sparker 
(estimated at 141 m; Table 6) was used as the basis of the take 
calculation for all marine mammals. Note that this results in a 
conservative estimate of the total ensonified area resulting from the 
proposed activities as Mayflower may not operate the Geomarine Geo-
Spark 400 tip sparker during the entire proposed survey, and for any 
survey segments in which it is not ultimately operated, the distance to 
the Level B harassment threshold would be less than 141 m (Table 6). 
However, as Mayflower cannot predict the precise number of survey days 
that will require the use of the Geomarine Geo-Spark 400 tip sparker, 
it was assumed that it would be operated during the entire duration of 
the proposed surveys.

           Table 6--Modeled Radial Distances From HRG Survey Equipment to Isopleths Corresponding to Level A and Level B Harassment Thresholds
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                           Radial distance to level A harassment threshold (m) *         Radial distance
                                                                   --------------------------------------------------------------------    to level B
                                                                                                                                           harassment
                           Sound source                                                                                                  threshold  (m)
                                                                     Low frequency   Mid frequency   High frequency   Phocid pinnipeds -----------------
                                                                       cetaceans       cetaceans        cetaceans        (underwater)      All marine
                                                                                                                                             mammals
--------------------------------------------------------------------------------------------------------------------------------------------------------
Innomar SES-2000 Medium-100 Parametric............................              <1              <1                60                <1               116

[[Page 31873]]

 
Edgetech 2000-DSS.................................................              <1              <1                 3                <1                 5
Geomarine Geo-Spark 400 tip sparker (800 Joules)..................              <1              <1                 8                <1               141
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Distances to the Level A harassment threshold based on the larger of the dual criteria (peak SPL and SELcum) are shown. For all sources the SELcum
  metric resulted in larger isopleth distances.

    Predicted distances to Level A harassment isopleths, which vary 
based on marine mammal functional hearing groups (Table 5), were also 
calculated. The updated acoustic thresholds for impulsive sounds (such 
as HRG survey equipment) contained in the Technical Guidance (NMFS, 
2018) were presented as dual metric acoustic thresholds using both 
cumulative sound exposure level (SELcum) and peak sound 
pressure level metrics. As dual metrics, NMFS considers onset of PTS 
(Level A harassment) to have occurred when either one of the two 
metrics is exceeded (i.e., the metric resulting in the largest 
isopleth). The SELcum metric considers both level and 
duration of exposure, as well as auditory weighting functions by marine 
mammal hearing group.
    Modeling of distances to isopleths corresponding to the Level A 
harassment threshold was performed for all types of HRG equipment 
proposed for use with the potential to result in harassment of marine 
mammals. Mayflower used a new model developed by JASCO to calculate 
distances to Level A harassment isopleths based on both the peak SPL 
and the SELcum metric. For the peak SPL metric, the model is 
a series of equations that accounts for both seawater absorption and 
HRG equipment beam patterns (for all HRG sources with beam widths 
larger than 90[deg], it was assumed these sources were 
omnidirectional). For the SELcum metric, a model was 
developed that accounts for the hearing sensitivity of the marine 
mammal group, seawater absorption, and beam width for downwards-facing 
transducers. Details of the modeling methodology for both the peak SPL 
and SELcum metrics are provided in Appendix A of the IHA 
application. This model entails the following steps:
    1. Weighted broadband source levels were calculated by assuming a 
flat spectrum between the source minimum and maximum frequency, 
weighted the spectrum according to the marine mammal hearing group 
weighting function (NMFS 2018), and summed across frequency;
    2. Propagation loss was modeled as a function of oblique range;
    3. Per-pulse SEL was modeled for a stationary receiver at a fixed 
distance off a straight survey line, using a vessel transit speed of 
3.5 knots and source-specific pulse length and repetition rate. The 
off-line distance is referred to as the closest point of approach (CPA) 
and was performed for CPA distances between 1 m and 10 km. The survey 
line length was modeled as 10 km long (analysis showed longer survey 
lines increased SEL by a negligible amount). SEL is calculated as SPL + 
10 log10 T/15 dB, where T is the pulse duration;
    4. The SEL for each survey line was calculated to produce curves of 
weighted SEL as a function of CPA distance; and
    5. The curves from Step 4 above were used to estimate the CPA 
distance to the impact criteria.
    We note that in the modeling methods described above and in 
Appendix A of the IHA application, sources that operate with a 
repetition rate greater than 10 Hz were assessed with the non-impulsive 
(intermittent) source criteria while sources with a repetition rate 
equal to or less than 10 Hz were assessed with the impulsive source 
criteria. NMFS does not necessarily agree with this step in the 
modeling assessment, which results in nearly all HRG sources being 
classified as impulsive; however, we note that the classification of 
the majority of HRG sources as impulsive results in more conservative 
modeling results. Thus, we have assessed the potential for Level A 
harassment to result from the proposed activities based on the modeled 
Level A zones with the acknowledgement that these zones are likely 
conservative.
    Modeled isopleth distances to Level A harassment thresholds for all 
types of HRG equipment and all marine mammal functional hearing groups 
are shown in Table 6. The dual criteria (peak SPL and 
SELcum) were applied to all HRG sources using the modeling 
methodology as described above, and the largest isopleth distances for 
each functional hearing group were then carried forward in the exposure 
analysis to be conservative. For all HRG sources, the SELcum 
metric resulted in larger isopleth distances. Distances to the Level A 
harassment threshold based on the larger of the dual criteria (peak SPL 
and SELcum) are shown in Table 6.
    Modeled distances to isopleths corresponding to the Level A 
harassment threshold are very small (<1 m) for three of the four marine 
mammal functional hearing groups that may be impacted by the proposed 
activities (i.e., low frequency and mid frequency cetaceans, and phocid 
pinnipeds; see Table 6). Based on the very small Level A harassment 
zones for these functional hearing groups, the potential for species 
within these functional hearing groups to be taken by Level A 
harassment is considered so low as to be discountable. For harbor 
porpoises (a high frequency specialist), the largest modeled distance 
to the Level A harassment threshold for the high frequency functional 
hearing group was 60 m (Table 6). However, as noted above, modeled 
distances to isopleths corresponding to the Level A harassment 
threshold are assumed to be conservative. Further, the Innomar source 
uses a very narrow beam width (two degrees) and the distances to the 
Level A harassment isopleths are eight meters or less for the other two 
sources. Level A harassment would also be more likely to occur at close 
approach to the sound source or as a result of longer duration exposure 
to the sound source, and mitigation measures--including a 100-m 
exclusion zone for harbor porpoises--are expected to minimize the 
potential for close approach or longer duration exposure to active HRG

[[Page 31874]]

sources. In addition, harbor porpoises are a notoriously shy species 
which is known to avoid vessels, and would also be expected to avoid a 
sound source prior to that source reaching a level that would result in 
injury (Level A harassment). Therefore, we have determined that the 
potential for take by Level A harassment of harbor porpoises is so low 
as to be discountable. As NMFS has determined that the likelihood of 
take of any marine mammals in the form of Level A harassment occurring 
as a result of the proposed surveys is so low as to be discountable, we 
therefore do not propose to authorize the take by Level A harassment of 
any marine mammals.

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) 
represent the best available information regarding marine mammal 
densities in the proposed survey area. The density data presented by 
Roberts et al. (2016, 2017, 2018) incorporates aerial and shipboard 
line-transect survey data from NMFS and other organizations and 
incorporates data from 8 physiographic and 16 dynamic oceanographic and 
biological covariates, and controls for 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 on the basis of 
additional data as well as certain methodological improvements. Our 
evaluation of the changes leads to a conclusion that these represent 
the best scientific evidence available. More information, including the 
model results and supplementary information for each model, is 
available online at seamap.env.duke.edu/models/Duke-EC-GOM-2015/. 
Marine mammal density estimates in the project area (animals/km\2\) 
were obtained using these model results (Roberts et al., 2016, 2017, 
2018). The updated models incorporate additional sighting data, 
including sightings from the NOAA Atlantic Marine Assessment Program 
for Protected Species (AMAPPS) surveys from 2010-2014 (NEFSC & SEFSC, 
2011, 2012, 2014a, 2014b, 2015, 2016).
    For the exposure analysis, density data from Roberts et al. (2016, 
2017, 2018) were mapped using a geographic information system (GIS). 
These data provide abundance estimates for species or species guilds 
within 10 km x 10 km grid cells (100 km\2\) on a monthly or annual 
basis, depending on the species. In order to select a representative 
sample of grid cells in and near the Project Area, a 10-km wide 
perimeter around the Lease Area and an 8-km wide perimeter around the 
cable route were created in GIS (ESRI 2017). The perimeters were then 
used to select grid cells near the Project Area containing the most 
recent monthly or annual estimates for each species in the Roberts et 
al. (2016, 2017, 2018) data. The average monthly abundance for each 
species in each survey area (deep-water and shallow-water) was 
calculated as the mean value of the grid cells within each survey 
portion in each month (June through September), and then converted for 
density (individuals/km\2\) by dividing by 100 km\2\ (Tables 7 and 8).
    Roberts et al. (2018) produced density models for all seals and did 
not differentiate by seal species. Because the seasonality and habitat 
use by gray seals roughly overlaps with that of harbor seals in the 
survey areas, it was assumed that modeled takes of seals could occur to 
either of the respective species, thus the total number of modeled 
takes for seals was applied to each species.

   Table 7--Average Monthly Densities for Species in the Lease Area and Deep-Water Section of the Cable Route
----------------------------------------------------------------------------------------------------------------
                                                            Estimated monthly density (individuals/km2)
                     Species                     ---------------------------------------------------------------
                                                       June            July           August         September
----------------------------------------------------------------------------------------------------------------
Fin whale.......................................          0.0032          0.0033          0.0029          0.0025
Humpback whale..................................          0.0014          0.0011          0.0005          0.0011
Minke whale.....................................          0.0024          0.0010          0.0007          0.0008
North Atlantic right whale......................          0.0012          0.0000          0.0000          0.0000
Sei whale.......................................          0.0002          0.0001          0.0000          0.0001
Atlantic white-sided dolphin....................          0.0628          0.0446          0.0243          0.0246
Bottlenose dolphin..............................          0.0249          0.0516          0.0396          0.0494
Harbor porpoise.................................          0.0188          0.0125          0.0114          0.0093
Pilot whale.....................................          0.0066          0.0066          0.0066          0.0066
Risso's dolphin.................................          0.0002          0.0005          0.0009          0.0007
Common dolphin..................................          0.0556          0.0614          0.1069          0.1711
Sperm whale.....................................          0.0001          0.0004          0.0004          0.0002
Seals (harbor and gray).........................          0.0260          0.0061          0.0033          0.0040
----------------------------------------------------------------------------------------------------------------


         Table 8--Average Monthly Densities for Species in the Shallow-Water Section of the Cable Route
----------------------------------------------------------------------------------------------------------------
                                                           Estimated monthly density (individuals/km\2\)
                     Species                     ---------------------------------------------------------------
                                                       June            July           August         September
----------------------------------------------------------------------------------------------------------------
Fin whale.......................................          0.0003          0.0003          0.0003          0.0003
Humpback whale..................................          0.0001          0.0001          0.0000          0.0001
Minke whale.....................................          0.0002          0.0000          0.0000          0.0000
North Atlantic right whale......................          0.0000          0.0000          0.0000          0.0000
Sei whale.......................................          0.0000          0.0000          0.0000          0.0000
Atlantic white-sided dolphin....................          0.0010          0.0006          0.0005          0.0008
Bottlenose dolphin..............................          0.2308          0.4199          0.3211          0.3077
Harbor porpoise.................................          0.0048          0.0023          0.0037          0.0036

[[Page 31875]]

 
Pilot whale.....................................          0.0000          0.0000          0.0000          0.0000
Risso's dolphin.................................          0.0000          0.0000          0.0000          0.0000
Common dolphin..................................          0.0003          0.0002          0.0006          0.0009
Sperm whale.....................................          0.0000          0.0000          0.0000          0.0000
Seals (harbor and gray).........................          0.2496          0.0281          0.0120          0.0245
----------------------------------------------------------------------------------------------------------------

Take Calculation and Estimation

    Here we describe how the information provided above is brought 
together to produce a quantitative take estimate.
    In order to estimate the number of marine mammals predicted to be 
exposed to sound levels that would result in harassment, radial 
distances to predicted isopleths corresponding to harassment thresholds 
are calculated, as described above. Those distances are then used to 
calculate the area(s) around the HRG survey equipment predicted to be 
ensonified to sound levels that exceed harassment thresholds. The area 
estimated to be ensonified to relevant thresholds in a single day 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. Mayflower estimates that the proposed survey 
vessel in the Lease Area and deep-water sections of the cable route 
will achieve a maximum daily trackline of 110 km per day and the 
proposed survey vessels in the shallow-water section of the cable route 
will achieve a maximum of 55 km per day during proposed HRG surveys. 
This distance accounts for survey vessels traveling at roughly 3 knots 
and accounts for non-active survey periods.
    Based on the maximum estimated distance to the Level B harassment 
threshold of 141 m (Table 6) and the maximum estimated daily track line 
distance of 110 km, an area of 31.1 km\2\ would be ensonified to the 
Level B harassment threshold each day in the Lease Area and deep-water 
section of the cable route during Mayflower's proposed surveys. During 
90 days of anticipated survey activity over the four month period (June 
through September), approximately 22.5 days of survey activity are 
expected each month, for an average of 699.4 km\2\ ensonified to the 
Level B harassment threshold in the Lease Area and deep-water section 
of the cable route each month of survey activities.
    Similarly, based on the maximum estimated distance to the Level B 
harassment threshold of 141 m (Table 6) and the maximum estimated daily 
track line distance of 55 km, an area of 15.6 km\2\ would be ensonified 
to the Level B harassment threshold each day in the shallow-water 
section of the cable route. During 125 days of anticipated survey 
activity over the four month period (June through September), 
approximately 31.3 days of survey activity (split among two vessels) 
are expected each month, for an average of 486.6 km\2\ ensonified to 
the Level B harassment threshold in the shallow-water section of the 
cable route each month of survey activities.
    As described above, this is a conservative estimate as it assumes 
the HRG sources that result in the greatest isopleth distances to the 
Level B harassment threshold would be operated at all times during all 
215 vessel days.
    The estimated numbers of marine mammals that may be taken by Level 
B harassment were calculated by multiplying the monthly density for 
each species in each survey area (Table 7 and 8) by the respective 
monthly ensonified area within each survey section. The results were 
then summed to determine the total estimated take (Table 9).

       Table 9--Numbers of Potential Incidental Take of Marine Mammals Proposed for Authorization and Proposed Takes as a Percentage of Population
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Calculated take by survey
                                                                      region                   Total                                      Total proposed
                                                         --------------------------------   calculated    Proposed takes  Proposed takes   instances of
                         Species                          Lease area and                     takes by       by  level A     by  level B      take as a
                                                             deep-water    Shallow-water      level B       harassment    harassment \b\   percentage of
                                                            cable route     cable route     harassment                                    population \a\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fin whale...............................................             8.3             0.6             8.9               0               9             0.3
Humpback whale..........................................             2.9             0.2             3.1               0               4             0.2
Minke whale.............................................             3.4             0.2             3.6               0               4             0.1
North Atlantic right whale..............................             0.9               0             0.9               0           \c\ 3             0.8
Sei whale...............................................             0.3               0             0.3               0           \c\ 2             0.4
Atlantic white-sided dolphin............................           109.3             1.4           110.7               0             111             0.1
Bottlenose dolphin......................................           115.7           622.6           738.3               0             739             1.0
Harbor porpoise.........................................            36.4               7            43.4               0              44             0.1
Pilot whale.............................................            18.4               0            18.4               0              19             0.1
Risso's dolphin.........................................             1.7               0             1.7               0           \b\ 6             0.1
Common dolphin..........................................           276.3               1           277.2               0             278             0.2
Sperm whale.............................................             0.8               0             0.8               0           \c\ 2             0.0

[[Page 31876]]

 
Seals (harbor and gray).................................            40.4           152.8           193.2               0             194             0.7
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Calculations of percentage of stock taken are based on the best available abundance estimate as shown in Table 3. In most cases the best available
  abundance estimate is provided by Roberts et al. (2016, 2017, 2018), when available, to maintain consistency with density estimates derived from
  Roberts et al. (2016, 2017, 2018). For bottlenose dolphins and seals, Roberts et al. (2016, 2017, 2018) provides only a single abundance estimate and
  does not provide abundance estimates at the stock or species level (respectively), so the abundance estimate used to estimate percentage of stock
  taken for bottlenose dolphins is derived from NMFS SARs (Hayes et al., 2019). For seals, NMFS proposes to authorize 194 takes of seals as a guild by
  Level B harassment and assumes take could occur to either species. For the purposes of estimating percentage of stock taken, the NMFS SARs abundance
  estimate for gray seals was used as the abundance of gray seals is lower than that of harbor seals (Hayes et al., 2019).
\b\ Proposed take equal to calculated take rounded up to next integer, or mean group size.
\c\ Proposed take increased to mean group size (Palka et al., 2017; Kraus et al., 2016).

    Using the take methodology approach described above, the take 
estimates for Risso's dolphin, sei whale, North Atlantic right whale, 
and sperm whale were less than the average group sizes estimated for 
these species (Table 9). However, information on the social structures 
of these species indicates these species are likely to be encountered 
in groups. Therefore it is reasonable to conservatively assume that one 
group of each of these species will be taken during the proposed 
survey. We therefore propose to authorize the take of the average group 
size for these species to account for the possibility that the proposed 
survey encounters a group of either of these species (Table 9).
    As described above, NMFS has determined that the likelihood of take 
of any marine mammals in the form of Level A harassment occurring as a 
result of the proposed surveys is so low as to be discountable; 
therefore, we do not propose to authorize take of any marine mammals by 
Level A harassment.

Proposed Mitigation

    In order to issue an IHA under Section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to 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, we 
carefully consider two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned), the likelihood of effective implementation (probability 
implemented as planned), and;
    (2) the practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.

Proposed Mitigation Measures

    NMFS proposes the following mitigation measures be implemented 
during Mayflower's proposed marine site characterization surveys.

Marine Mammal Exclusion Zones, Buffer Zone and Monitoring Zone

    Marine mammal exclusion zones (EZ) would be established around the 
HRG survey equipment and monitored by protected species observers (PSO) 
during HRG surveys as follows:
     A 500-m EZ would be required for North Atlantic right 
whales; and
     A 100-m EZ would be required for all other marine mammals 
(with the exception of certain small dolphin species specified below).
    If a marine mammal is detected approaching or entering the EZs 
during the proposed survey, the vessel operator would adhere to the 
shutdown procedures described below. In addition to the EZs described 
above, PSOs would visually monitor a 200 m Buffer Zone. During use of 
acoustic sources with the potential to result in marine mammal 
harassment (i.e., anytime the acoustic source is active, including 
ramp-up), occurrences of marine mammals within the Buffer Zone (but 
outside the EZs) would be communicated to the vessel operator to 
prepare for potential shutdown of the acoustic source. The Buffer Zone 
is not applicable when the EZ is greater than 100 meters. PSOs would 
also be required to observe a 500-m Monitoring Zone and record the 
presence of all marine mammals within this zone. In addition, any 
marine mammals observed within 141 m of the active HRG equipment 
operating at or below 180 kHz would be documented by PSOs as taken by 
Level B harassment. The zones described above would be based upon the 
radial distance from the active equipment (rather than being based on 
distance from the vessel itself).

Visual Monitoring

    A minimum of one NMFS-approved PSO must be on duty and conducting 
visual observations at all times during daylight hours (i.e., from 30 
minutes prior to sunrise through 30 minutes following sunset) and 30 
minutes prior

[[Page 31877]]

to and during nighttime ramp-ups of HRG equipment. Visual monitoring 
would begin no less than 30 minutes prior to ramp-up of HRG equipment 
and would continue until 30 minutes after use of the acoustic source 
ceases or until 30 minutes past sunset. PSOs would establish and 
monitor the applicable EZs, Buffer Zone and Monitoring Zone as 
described above. Visual PSOs would coordinate to ensure 360[deg] visual 
coverage around the vessel from the most appropriate observation posts, 
and would conduct visual observations using binoculars and the naked 
eye while free from distractions and in a consistent, systematic, and 
diligent manner. PSOs would estimate distances to marine mammals 
located in proximity to the vessel and/or relevant using range finders. 
It would be the responsibility of the Lead PSO on duty to communicate 
the presence of marine mammals as well as to communicate and enforce 
the action(s) that are necessary to ensure mitigation and monitoring 
requirements are implemented as appropriate. Position data would be 
recorded using hand-held or vessel global positioning system (GPS) 
units for each confirmed marine mammal sighting.

Pre-Clearance of the Exclusion Zones

    Prior to initiating HRG survey activities, Mayflower would 
implement a 30-minute pre-clearance period. During pre-clearance 
monitoring (i.e., before ramp-up of HRG equipment begins), the Buffer 
Zone would also act as an extension of the 100-m EZ in that 
observations of marine mammals within the 200-m Buffer Zone would also 
preclude HRG operations from beginning. During this period, PSOs would 
ensure that no marine mammals are observed within 200 m of the survey 
equipment (500 m in the case of North Atlantic right whales). HRG 
equipment would not start up until this 200-m zone (or, 500-m zone in 
the case of North Atlantic right whales) is clear of marine mammals for 
at least 30 minutes. The vessel operator would notify a designated PSO 
of the proposed start of HRG survey equipment as agreed upon with the 
lead PSO; the notification time should not be less than 30 minutes 
prior to the planned initiation of HRG equipment order to allow the 
PSOs time to monitor the EZs and Buffer Zone for the 30 minutes of pre-
clearance. A PSO conducting pre-clearance observations would be 
notified again immediately prior to initiating active HRG sources.
    If a marine mammal were observed within the relevant EZs or Buffer 
Zone during the pre-clearance period, initiation of HRG survey 
equipment would not begin until the animal(s) has been observed exiting 
the respective EZ or Buffer Zone, or, until an additional time period 
has elapsed with no further sighting (i.e., minimum 15 minutes for 
small odontocetes and seals, and 30 minutes for all other species). The 
pre-clearance requirement would include small delphinoids that approach 
the vessel (e.g., bow ride). PSOs would also continue to monitor the 
zone for 30 minutes after survey equipment is shut down or survey 
activity has concluded.

Ramp-Up of Survey Equipment

    When technically feasible, a ramp-up procedure would be used for 
geophysical survey equipment capable of adjusting energy levels at the 
start or re-start of survey activities. The ramp-up procedure would be 
used at the beginning of HRG survey activities in order to provide 
additional protection to marine mammals near the Project Area by 
allowing them to detect the presence of the survey and vacate the area 
prior to the commencement of survey equipment operation at full power. 
Ramp-up of the survey equipment would not begin until the relevant EZs 
and Buffer Zone has been cleared by the PSOs, as described above. HRG 
equipment would be initiated at their lowest power output and would be 
incrementally increased to full power. If any marine mammals are 
detected within the EZs or Buffer Zone prior to or during ramp-up, the 
HRG equipment would be shut down (as described below).

Shutdown Procedures

    If an HRG source is active and a marine mammal is observed within 
or entering a relevant EZ (as described above) an immediate shutdown of 
the HRG survey equipment would be required. When shutdown is called for 
by a PSO, the acoustic source would be immediately deactivated and any 
dispute resolved only following deactivation. Any PSO on duty would 
have the authority to delay the start of survey operations or to call 
for shutdown of the acoustic source if a marine mammal is detected 
within the applicable EZ. The vessel operator would establish and 
maintain clear lines of communication directly between PSOs on duty and 
crew controlling the HRG source(s) to ensure that shutdown commands are 
conveyed swiftly while allowing PSOs to maintain watch. Subsequent 
restart of the HRG equipment would only occur after the marine mammal 
has either been observed exiting the relevant EZ, or, until an 
additional time period has elapsed with no further sighting of the 
animal within the relevant EZ (i.e., 15 minutes for small odontocetes 
and seals, and 30 minutes for large whales).
    Upon implementation of shutdown, the HRG source may be reactivated 
after the marine mammal that triggered the shutdown has been observed 
exiting the applicable EZ (i.e., the animal is not required to fully 
exit the Buffer Zone where applicable) or, following a clearance period 
of 15 minutes for small odontocetes and seals and 30 minutes for all 
other species with no further observation of the marine mammal(s) 
within the relevant EZ. If the HRG equipment shuts down for brief 
periods (i.e., less than 30 minutes) for reasons other than mitigation 
(e.g., mechanical or electronic failure) the equipment may be re-
activated as soon as is practicable at full operational level, without 
30 minutes of pre-clearance, only if PSOs have maintained constant 
visual observation during the shutdown and no visual detections of 
marine mammals occurred within the applicable EZs and Buffer Zone 
during that time. For a shutdown of 30 minutes or longer, or if visual 
observation was not continued diligently during the pause, pre-
clearance observation is required, as described above.
    The shutdown requirement would be waived for certain genera of 
small delphinids (i.e., Delphinus, Lagenorhynchus, and Tursiops) under 
certain circumstances. If a delphinid(s) from these genera is visually 
detected approaching the vessel (i.e., to bow ride) or towed survey 
equipment, shutdown would not be required. 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 would use best professional judgment in 
making the decision to call for a shutdown.
    If a species for which authorization has not been granted, or, a 
species for which authorization has been granted but the authorized 
number of takes have been met, approaches or is observed within the 
area encompassing the Level B harassment isopleth (141 m), shutdown 
would occur.

Vessel Strike Avoidance

    Vessel strike avoidance measures would include, but would not be 
limited to, the following, except under circumstances when complying 
with these requirements would put the safety of the vessel or crew at 
risk:
     All vessel operators and crew will maintain vigilant watch 
for cetaceans and pinnipeds, and slow down or stop their vessel to 
avoid striking these protected species;

[[Page 31878]]

     All survey vessels, regardless of size, must observe a 10-
knot speed restriction in DMAs designated by NMFS for the protection of 
North Atlantic right whales from vessel strikes. Note that this 
requirement includes vessels, regardless of size, to adhere to a 10 
knot speed limit in DMAs, not just vessels 65 ft or greater in length;
     All vessel operators will reduce vessel speed to 10 knots 
(18.5 km/hr) or less when any large whale, any mother/calf pairs, large 
assemblages of non-delphinoid cetaceans are observed near (within 100 m 
(330 ft)) an underway vessel;
     All vessels will maintain a separation distance of 500 m 
(1,640 ft) or greater from any sighted North Atlantic right whale;
     If underway, vessels must steer a course away from any 
sighted North Atlantic right whale at 10 knots (18.5 km/hr) or less 
until the 500-m (1,640 ft) minimum separation distance has been 
established. If a North Atlantic right whale is sighted in a vessel's 
path, or within 100 m (330 ft) to an underway vessel, the underway 
vessel must reduce speed and shift the engine to neutral. Engines will 
not be engaged until the North Atlantic right whale has moved outside 
of the vessel's path and beyond 100 m. If stationary, the vessel must 
not engage engines until the North Atlantic right whale has moved 
beyond 100 m;
     All vessels will maintain a separation distance of 100 m 
(330 ft) or greater from any sighted non-delphinoid cetacean. If 
sighted, the vessel underway must reduce speed and shift the engine to 
neutral, and must not engage the engines until the non-delphinoid 
cetacean has moved outside of the vessel's path and beyond 100 m. If a 
survey vessel is stationary, the vessel will not engage engines until 
the non-delphinoid cetacean has moved out of the vessel's path and 
beyond 100 m;
     All vessels will maintain a separation distance of 50 m 
(164 ft) or greater from any sighted delphinoid cetacean. Any vessel 
underway remain parallel to a sighted delphinoid cetacean's course 
whenever possible, and avoid excessive speed or abrupt changes in 
direction. Any vessel underway reduces vessel speed to 10 knots (18.5 
km/hr) or less when pods (including mother/calf pairs) or large 
assemblages of delphinoid cetaceans are observed. Vessels may not 
adjust course and speed until the delphinoid cetaceans have moved 
beyond 50 m and/or the abeam of the underway vessel;
     All vessels will maintain a separation distance of 50 m 
(164 ft) or greater from any sighted pinniped; and
     All vessels underway will not divert or alter course in 
order to approach any whale, delphinoid cetacean, or pinniped. Any 
vessel underway will avoid excessive speed or abrupt changes in 
direction to avoid injury to the sighted cetacean or pinniped.
    Project-specific training will be conducted for all vessel crew 
prior to the start of survey activities. 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 
members understand and will comply with the necessary requirements 
throughout the survey activities.

Passive Acoustic Monitoring

    Vineyard Wind would also employ passive acoustic monitoring (PAM) 
to support monitoring during night time operations to provide for 
acquisition of species detections at night. While PAM is not typically 
required by NMFS for HRG surveys, it may a provide additional benefit 
as a mitigation and monitoring measure to further limit potential 
exposure to underwater sound at levels that could result in injury or 
behavioral harassment.
    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means 
effecting the least practicable impact on the affected species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance.

Proposed Monitoring and Reporting

    In order to issue an IHA for an activity, Section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104 (a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present in the 
proposed action area. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) Action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the action; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
Long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and
     Mitigation and monitoring effectiveness.

Proposed Monitoring Measures

    As described above, visual monitoring would be performed by 
qualified and NMFS-approved PSOs. Mayflower would use independent, 
dedicated, trained PSOs, meaning that the PSOs must be employed by a 
third-party observer provider, must have no tasks other than to conduct 
observational effort, collect data, and communicate with and instruct 
relevant vessel crew with regard to the presence of marine mammals and 
mitigation requirements (including brief alerts regarding maritime 
hazards), and must have successfully completed an approved PSO training 
course appropriate for their designated task. Mayflower would provide 
resumes of all proposed PSOs (including alternates) to NMFS for review 
and approval prior to the start of survey operations.
    During 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 and 
conducting visual observations at all times on all active survey 
vessels during daylight

[[Page 31879]]

hours (i.e., from 30 minutes prior to sunrise through 30 minutes 
following sunset) and nighttime ramp-ups of HRG equipment. Visual 
monitoring would begin no less than 30 minutes prior to initiation of 
HRG survey equipment and would continue until one hour after use of the 
acoustic source ceases or until 30 minutes past sunset. PSOs would 
coordinate to ensure 360[deg] visual coverage around the vessel from 
the most appropriate observation posts, and would conduct visual 
observations using binoculars 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 survey vessels.
    PSOs would be equipped with binoculars and have the ability to 
estimate distances to marine mammals located in proximity to the vessel 
and/or exclusion zone using range finders. Reticulated binoculars will 
also be available to PSOs for use as appropriate based on conditions 
and visibility to support the monitoring of marine mammals. Position 
data would be recorded using hand-held or vessel GPS units for each 
sighting. Observations would take place from the highest available 
vantage point on the survey vessel. General 360-degree scanning would 
occur during the monitoring periods, and target scanning by the PSO 
would occur when alerted of a marine mammal presence.
    During good conditions (e.g., daylight hours; Beaufort sea state 
(BSS) 3 or less), to the maximum extent practicable, PSOs would conduct 
observations when the acoustic source is not operating for comparison 
of sighting rates and behavior with and without use of the acoustic 
source and between acquisition periods. Any observations of marine 
mammals by crew members aboard any vessel associated with the survey 
would be relayed to the PSO team.
    Data on all PSO observations would be recorded based on standard 
PSO collection requirements. This would include dates, times, and 
locations of survey operations; dates and times of observations, 
location and weather; details of marine mammal sightings (e.g., 
species, numbers, behavior); and details of any observed marine mammal 
take that occurs (e.g., noted behavioral disturbances).

Proposed Reporting Measures

    Within 90 days after completion of survey activities, a final 
technical report will be provided to NMFS that fully documents the 
methods and monitoring protocols, summarizes the data recorded during 
monitoring, summarizes the number of marine mammals estimated to have 
been taken 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.
    In addition to the final technical report, Mayflower will provide 
the reports described below as necessary during survey activities. In 
the unanticipated event that Mayflower's activities lead to an injury 
(Level A harassment) of a marine mammal, Mayflower would immediately 
cease the specified activities and report the incident to the NMFS 
Office of Protected Resources Permits and Conservation Division and the 
NMFS Northeast Regional Stranding Coordinator. The report would include 
the following information:
     Time, date, and location (latitude/longitude) of the 
incident;
     Name and type of vessel involved;
     Vessel's speed during and leading up to the incident;
     Description of the incident;
     Status of all sound source use in the 24 hours preceding 
the incident;
     Water depth;
     Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, and visibility);
     Description of all marine mammal observations in the 24 
hours preceding the incident;
     Species identification or description of the animal(s) 
involved;
     Fate of the animal(s); and
     Photographs or video footage of the animal(s) (if 
equipment is available).
    Activities would not resume until NMFS is able to review the 
circumstances of the event. NMFS would work with Mayflower to minimize 
reoccurrence of such an event in the future. Mayflower would not resume 
activities until notified by NMFS.
    In the event that Mayflower personnel discover an injured or dead 
marine mammal, Mayflower would report the incident to the OPR Permits 
and Conservation Division and the NMFS Northeast Regional Stranding 
Coordinator as soon as feasible. The report would include the following 
information:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and
     General circumstances under which the animal was 
discovered.
    In the unanticipated event of a ship strike of a marine mammal by 
any vessel involved in the activities covered by the IHA, Mayflower 
would report the incident to the NMFS OPR Permits and Conservation 
Division and the NMFS Northeast Regional 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 31880]]

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any responses (e.g., intensity, duration), the context 
of any responses (e.g., critical reproductive time or location, 
migration), as well as effects on habitat, and the likely effectiveness 
of the mitigation. We also assess the number, intensity, and context of 
estimated takes by evaluating this information relative to population 
status. Consistent with the 1989 preamble for NMFS's implementing 
regulations (54 FR 40338; September 29, 1989), the impacts from other 
past and ongoing anthropogenic activities are incorporated into this 
analysis via their impacts on the environmental baseline (e.g., as 
reflected in the regulatory status of the species, population size and 
growth rate where known, ongoing sources of human-caused mortality, or 
ambient noise levels).
    To avoid repetition, our analysis applies to all the species listed 
in Table 3, given that NMFS expects the anticipated effects of the 
proposed survey to be similar in nature. NMFS does not anticipate that 
serious injury or mortality would result from HRG surveys, even in the 
absence of mitigation, and no serious injury or mortality is 
authorized. As discussed in the Potential Effects section, non-auditory 
physical effects and vessel strike are not expected to occur. We expect 
that 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 were occurring), reactions that 
are considered to be of low severity and with no lasting biological 
consequences (e.g., Southall et al., 2007). As described above, Level A 
harassment is not expected to result given the nature of the 
operations, the anticipated size of the Level A harassment zones, the 
density of marine mammals in the area, and the required shutdown zones.
    Effects on individuals that are taken by Level B harassment, on the 
basis of reports in the literature as well as monitoring from other 
similar activities, will likely be limited to reactions such as 
increased swimming speeds, increased surfacing time, or decreased 
foraging (if such activity were occurring). Most likely, individuals 
will simply move away from the sound source and temporarily avoid the 
area where the survey is occurring. We expect that any avoidance of the 
survey area by marine mammals would be temporary in nature and that any 
marine mammals that avoid the survey area during the survey activities 
would not be permanently displaced. 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.
    Regarding impacts to marine mammal habitat, prey species are 
mobile, and are broadly distributed throughout the Project Area and the 
footprint of the activity is small; therefore, marine mammals that may 
be temporarily displaced during survey activities are expected to be 
able to resume foraging once they have moved away from areas with 
disturbing levels of underwater noise. Because of the availability of 
similar habitat and resources in the surrounding area 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. The HRG survey equipment itself will not 
result in physical habitat disturbance. Avoidance of the area around 
the HRG survey activities by marine mammal prey species is possible. 
However, any avoidance by prey species would be expected to be short 
term and temporary.
    ESA-listed species for which takes are authorized are North 
Atlantic right, fin, sei, and sperm whales, and these effects are 
anticipated to be limited to lower level behavioral effects. The 
proposed survey is not anticipated to affect the fitness or 
reproductive success of individual animals. Since impacts to individual 
survivorship and fecundity are unlikely, the proposed survey is not 
expected to result in population-level effects for any ESA-listed 
species or alter current population trends of any ESA-listed species.
    The status of the North Atlantic right whale population is of 
heightened concern and, therefore, merits additional analysis. NMFS has 
rigorously assessed potential impacts to right whales from this survey. 
We have established a 500-m shutdown zone for right whales which is 
precautionary considering the Level B harassment isopleth for the 
largest source utilized (i.e., GeoMarine Geo-Source 400 tip sparker) is 
estimated to be 141 m.
    The proposed Project Area encompasses or is in close proximity to 
feeding BIAs for right whales (February-April), humpback whales (March-
December), fin whales (March-October), and sei whales (May-November) as 
well as a migratory BIA for right whales (March-April and November-
December. Most of these feeding BIAs are extensive and sufficiently 
large (705 km\2\ and 3,149 km\2\ for right whales; 47,701 km\2\ for 
humpback whales; 2,933 km\2\ for fin whales; and 56,609 km\2\ for sei 
whales), and the acoustic footprint of the proposed survey is 
sufficiently small, that feeding opportunities for these whales would 
not be reduced appreciably. Any whales temporarily displaced from the 
proposed Project Area would be expected to have sufficient remaining 
feeding habitat available to them, and would not be prevented from 
feeding in other areas within the biologically important feeding 
habitat. In addition, any displacement of whales from the BIA or 
interruption of foraging bouts would be expected to be temporary in 
nature. Therefore, we do not expect impacts to whales within feeding 
BIAs to to effect the fitness of any large whales.
    A migratory BIA for North Atlantic right whales (effective March-
April and November-December) extends from Massachusetts to Florida 
(LaBrecque, et al., 2015). Off the south coast of Massachusetts and 
Rhode Island, this BIA extends from the coast to beyond the shelf 
break. The fact that the spatial acoustic footprint of the proposed 
survey is very small relative to the spatial extent of the available 
migratory habitat means that right whale migration is not expected to 
be impacted by the proposed survey. Required vessel strike avoidance 
measures will also decrease risk of ship strike during migration. NMFS 
is expanding the standard avoidance measures by requiring that all 
vessels, regardless of size, adhere to a 10 knot speed limit in any 
established DMAs. Additionally, limited take by Level B harassment of 
North Atlantic right whales has been proposed as HRG survey operations 
are required to shut down at 500 m to minimize the potential for 
behavioral harassment of this species.

[[Page 31881]]

    As noted previously, there are several active UMEs occurring in the 
vicinity of Mayflower's proposed surveys. Elevated humpback whale 
mortalities have occurred along the Atlantic coast from Maine through 
Florida since January 2016. Of the cases examined, approximately half 
had evidence of human interaction (ship strike or entanglement). The 
UME does not yet provide cause for concern regarding population-level 
impacts. Despite the UME, the relevant population of humpback whales 
(the West Indies breeding population, or distinct population segment 
(DPS)) remains stable. 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 North Atlantic right whale mortalities 
began in June 2017, primarily in Canada. Overall, preliminary findings 
support human interactions, specifically vessel strikes or rope 
entanglements, as the cause of death for the majority of the right 
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 (345) is 
well below PBR (2,006) (Hayes et al., 2018). For gray seals, the 
population abundance in the United States is over 27,000, with an 
estimated abundance including seals in Canada of approximately 505,000, 
and abundance is likely increasing in the U.S. Atlantic EEZ as well as 
in Canada (Hayes et al., 2018).
    Direct physical interactions (ship strikes and entanglements) 
appear to be responsible for many of the UME humpback and right whale 
mortalities recorded. The proposed HRG survey will require ship strike 
avoidance measures which would minimize the risk of ship strikes while 
fishing gear and in-water lines will not be employed as part of the 
survey. Furthermore, the proposed activities are not expected to 
promote the transmission of infectious disease among marine mammals. 
The survey is not expected to result in the deaths of any marine 
mammals or combine with the effects of the ongoing UMEs to result in 
any additional impacts not analyzed here. Accordingly, Mayflower did 
not request, and NMFS is not proposing to authorize, take of marine 
mammals by serious injury, or mortality.
    The required mitigation measures are expected to reduce the number 
and/or severity of takes by giving animals the opportunity to move away 
from the sound source before HRG survey equipment reaches full energy 
and preventing animals from being exposed to sound levels that have the 
potential to cause injury (Level A harassment) and more severe Level B 
harassment during HRG survey activities, even in the biologically 
important areas described above. No Level A harassment is anticipated 
or authorized.
    NMFS expects that takes would be in the form of short-term Level B 
behavioral harassment in the form of brief startling reaction and/or 
temporary vacating of the area, or decreased foraging (if such activity 
were occurring)--reactions that (at the scale and intensity anticipated 
here) are considered to be of low severity and with no lasting 
biological consequences. Since both the source and the marine mammals 
are mobile, only a smaller area would be ensonified by sound levels 
that could result in take for only a short period. Additionally, 
required mitigation measures would reduce exposure to sound that could 
result in more severe behavioral harassment.
    In summary and as described above, the following factors primarily 
support our preliminary determination that the impacts resulting from 
this activity are not expected to adversely affect the species or stock 
through effects on annual rates of recruitment or survival:
     No mortality or serious injury is anticipated or proposed 
to be authorized;
     No Level A harassment (PTS) is anticipated;
     Any foraging interruptions are expected to be short term 
and unlikely to be cause significantly impacts;
     Impacts on marine mammal habitat and species that serve as 
prey species for marine mammals are expected to be minimal and the 
alternate areas of similar habitat value for marine mammals are readily 
available;
     Take is anticipated to be primarily Level B behavioral 
harassment consisting of brief startling reactions and/or temporary 
avoidance of the Project Area;
     Survey activities would occur in such a comparatively 
small portion of the biologically important area for north Atlantic 
right whale migration, that any avoidance of the Project Area due to 
activities would not affect migration. In addition, mitigation measures 
to shut down at 500 m to minimize potential for Level B behavioral 
harassment would limit both the number and severity of take of the 
species;
     Similarly, due to the relatively small footprint of the 
survey activities in relation to the size of a biologically important 
areas for right, humpback, fin, and sei whales foraging, the survey 
activities would not affect foraging success of this species; and
     Proposed mitigation measures, including visual monitoring 
and shutdowns, are expected to minimize the intensity of 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 proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the Mayflower's proposed HRG surveys will have a 
negligible impact on all affected marine mammal species or stocks.

Small Numbers

    As noted above, only small numbers of incidental take may be 
authorized under Sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether an authorization is limited to 
small numbers of marine mammals. Additionally, other qualitative 
factors may be considered in the analysis, such as the temporal or 
spatial scale of the activities.
    The numbers of marine mammals that we authorize to be taken, for 
all species and stocks, would be considered small relative to the 
relevant stocks or populations (less than one third of the best 
available population abundance for all species and stocks) (see Table 
9). In fact, the total amount of taking proposed for authorization for 
all species is 1 percent or less for all affected stocks.
    Based on the analysis contained herein of the proposed activity 
(including the proposed mitigation and monitoring measures) and the

[[Page 31882]]

anticipated take of marine mammals, NMFS preliminarily 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.

Endangered Species Act (ESA)

    Section 7(a)(2) of the Endangered Species Act of 1973 (16 U.S.C. 
1531 et seq.) requires that each Federal agency insure that any action 
it authorizes, funds, or carries out is not likely to jeopardize the 
continued existence of any endangered or threatened species or result 
in the destruction or adverse modification of designated critical 
habitat. To ensure ESA compliance for the issuance of IHAs, NMFS 
consults internally, in this case with the NMFS Greater Atlantic 
Regional Fisheries Office (GARFO), whenever we propose to authorize 
take for endangered or threatened species.
    The NMFS Office of Protected Resources Permits and Conservation 
Division is proposing to authorize the incidental take of four species 
of marine mammals listed under the ESA: The North Atlantic right, fin, 
sei, and sperm whale. The Permits and Conservation Division has 
requested initiation of Section 7 consultation with NMFS GARFO for the 
issuance of this IHA. NMFS will conclude the ESA section 7 consultation 
prior to reaching a determination regarding the proposed issuance of 
the authorization.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to Mayflower for conducting marine site characterization 
surveys offshore of Massachusetts in the area of the Commercial Lease 
of Submerged Lands for Renewable Energy Development on the Outer 
Continental Shelf (OCS-A 0521) and along a potential submarine cable 
route to landfall at Falmouth, Massachusetts for a period of one year 
from the date of issuance, provided the previously mentioned 
mitigation, monitoring, and reporting requirements are incorporated. A 
draft of the proposed IHA can be found at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.

Request for Public Comments

    We request comment on our analyses, the proposed authorization, and 
any other aspect of this Notice of Proposed IHA for the proposed HRG 
survey. We also request at this time comment on the potential Renewal 
of this proposed IHA as described in the paragraph below. Please 
include with your comments any supporting data or literature citations 
to help inform decisions on the request for this IHA or a subsequent 
Renewal IHA.
    On a case-by-case basis, NMFS may issue a one-year Renewal IHA 
following notice to the public providing an additional 15 days for 
public comments when (1) up to another year of identical or nearly 
identical, or nearly identical, activities as described in the 
Specified Activities section of this notice is planned or (2) the 
activities as described in the Specified Activities section of this 
notice would not be completed by the time the IHA expires and a Renewal 
would allow for completion of the activities beyond that described in 
the Dates and Duration section of this notice, provided all of the 
following conditions are met:
     A request for renewal is received no later than 60 days 
prior to the needed Renewal IHA effective date (recognizing that the 
Renewal IHA expiration date cannot extend beyond one year from 
expiration of the initial IHA);
     The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
requested Renewal IHA are identical to the activities analyzed under 
the initial IHA, are a subset of the activities, or include changes so 
minor (e.g., reduction in pile size) that the changes do not affect the 
previous analyses, mitigation and monitoring requirements, or take 
estimates (with the exception of reducing the type or amount of take); 
and
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized; and
     Upon review of the request for Renewal, the status of the 
affected species or stocks, and any other pertinent information, NMFS 
determines that there are no more than minor changes in the activities, 
the mitigation and monitoring measures will remain the same and 
appropriate, and the findings in the initial IHA remain valid.

    Dated: May 19, 2020.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2020-11203 Filed 5-26-20; 8:45 am]
BILLING CODE 3510-22-P