[Federal Register Volume 86, Number 23 (Friday, February 5, 2021)]
[Notices]
[Pages 8490-8536]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-02263]



[[Page 8489]]

Vol. 86

Friday,

No. 23

February 5, 2021

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 Construction of the South Fork Offshore 
Wind Project; Notice

  Federal Register / Vol. 86 , No. 23 / Friday, February 5, 2021 / 
Notices  

[[Page 8490]]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XA661]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Construction of the South Fork 
Offshore Wind Project

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 South Fork Wind, LLC (South 
Fork Wind) to take marine mammals incidental to construction of a 
commercial wind energy project southeast of Rhode Island, within the 
Rhode Island-Massachusetts Wind Energy Area (RI/MA WEA). 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-time, 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 March 
10, 2021.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service and 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, including all attachments, must 
not exceed a 25-megabyte file size. Attachments to 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 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: Carter Esch, Office of Protected 
Resources, NMFS, (301) 427-8421. 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: 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 such species or stocks for 
taking for certain subsistence uses (referred to in shorthand as 
``mitigation''); and requirements pertaining to the mitigation, 
monitoring and reporting of such takings are set forth.
    The definitions of all applicable MMPA statutory terms cited above 
are included in the relevant sections below.

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. In compliance with NEPA, as implemented by 
the regulations published by the Council on Environmental Quality (40 
CFR parts 1500-1508 (1978)), the Bureau of Ocean Energy Management 
(BOEM) prepared an Environmental Impact Statement (EIS) to consider the 
direct, indirect and cumulative effects to the human environment 
resulting from the South Fork Wind project. NMFS is a cooperating 
agency on BOEM's EIS. Accordingly, NMFS plans to adopt the Bureau of 
Ocean Energy Management's (BOEM) Environmental Impact Statement (EIS), 
provided our independent evaluation of the document finds that it 
includes adequate information analyzing the effects of the proposed IHA 
issuance on the human environment. BOEM's draft EIS was made available 
for public comment from January 8, 2021 to February 22, 2021 and is 
available at: www.boem.gov/South Fork-Wind.
    NMFS 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.
    This project is covered under Title 41 of the Fixing America's 
Surface Transportation Act, or ``FAST-41.'' FAST-41 includes a suite of 
provisions designed to expedite the environmental review for covered 
infrastructure projects, including enhanced interagency coordination as 
well as milestone tracking on the public-facing Permitting Dashboard. 
The dashboard for this project is available at https://www.permits.performance.gov/permitting-projects/south-fork-wind-farm-and-south-fork-export-cable.

Summary of Request

    On March 15, 2019, NMFS received a request from South Fork Wind for 
an IHA to take marine mammals incidental to construction of an offshore 
wind energy project southeast of Rhode Island. Following a delay of the 
project, South Fork Wind submitted an updated version of the 
application on June 3, 2020, and then a revised version September 14, 
2020. The application was deemed adequate and complete on September 15, 
2020. However, on December 15, 2020, South Fork Wind

[[Page 8491]]

submitted a subsequent application due to changes to the project scope. 
NMFS deemed the application adequate and complete on December 16, 2020. 
South Fork Wind's request is for take of 16 species of marine mammals 
by harassment. Neither South Fork Wind nor NMFS expects serious injury 
or mortality to result from this activity and, therefore, an IHA is 
appropriate.

Description of Proposed Activity

Overview

    South Fork Wind proposes to construct a 90-180 megawatt (MW) 
offshore wind energy project in Lease Area OCS-A 0517, southeast of 
Rhode Island. The project would consist of installation of up 16 
monopiles to support 15 offshore wind turbine generators (WTGs) and one 
offshore substation (OSS) (Figure 1). The project also includes 
offshore and onshore cabling, and onshore operations and maintenance 
facilities. Take of marine mammals may occur incidental to the 
construction of the project due to in-water noise exposure resulting 
from impact pile driving activities associated with installation of WTG 
and OSS foundations, vibratory pile driving associated with the 
installation and removal of a temporary cofferdam nearshore, and high-
resolution geophysical (HRG) surveys of the inter-array cable and 
export cable construction area.

Dates and Duration

    Construction of the project is planned to commence between April 
2022 and May 2022; however, as with many construction projects, 
permitting and construction delays may occur and the activity may take 
place at any point during the period of effectiveness for the IHA, 
subject to the following timing constraints. Up to 30 days of impact 
pile driving to install the WTGs and OSS may occur between May 1, 2022 
and December 31, 2022; no impact pile driving activities would occur 
from January 1, 2023 through April 30, 2023. A cofferdam may 
potentially be installed for the sea-to-shore cable connection and, if 
required, would be installed between October 1, 2022 and May 31, 2023. 
Installation and extraction of the cofferdam are each expected to take 
1 to 3 days of vibratory pile driving. Up to 60 days of HRG surveys 
would be conducted throughout the 12-month construction timeframe.

Specific Geographic Region

    South Fork Wind's proposed activity would occur in the 55.4 square 
kilometer (km\2\) (13,700 acre) South Fork Wind Lease Area OCS-A 0517 
(SFWF; Figure 1 here, and see Figure 1 in the IHA application for more 
detail), within the Rhode Island-Massachusetts WEA. At its nearest 
point, the SFWF would be just over 30 kilometers (km) (19 miles (mi)) 
southeast of Block Island, Rhode Island, and 56 km (35 mi) east of 
Montauk Point, New York. Water depths in the SFWF range from 
approximately 33-41 meters (m) (108-134 feet (ft)). The South Fork 
export cable route (SFEC) would connect SFWF to one of two landing 
locations on Long Island, New York, where a temporary cofferdam may be 
constructed where the SFEC exits the seabed.
BILLING CODE 3510-22-P

[[Page 8492]]

[GRAPHIC] [TIFF OMITTED] TN05FE21.000

BILLING CODE 3510-22-C

Detailed Description of Specific Activity

    South Fork Wind is proposing to construct a 90-180 MW commercial 
wind energy project in Lease Area OCS-A 0517, southeast of Rhode 
Island. The Project would consist of the installation of up to 16 
monopiles to support 15

[[Page 8493]]

offshore WTGs and one OSS, an onshore substation, offshore and onshore 
cabling, and onshore operations and maintenance facilities. WTGs would 
be arranged in a grid-like pattern with spacing of 1.9 km (1.15 mi; 1 
nautical miles (nm)) between turbines. Each WTG would interconnect with 
the OSS via an inter-array submarine cable system. The offshore export 
cable transmission system would connect the OSS to an existing mainland 
electric grid in East Hampton, New York. A temporary cofferdam may be 
installed where the offshore export cable conduit exits from the seabed 
to contain drilling returns and prevent the excavated sediments from 
silting back into the Horizontal Directional Drill (HDD) exit pit. The 
final location of the cofferdam will be dependent upon the selected 
cable landing site. Construction of the WTGs and OSS, including pile 
driving, could occur on any day from May 1, 2022 through December 31, 
2022. Cofferdam installation and extraction requiring vibratory pile 
driving could occur for up to 3 days from October 2022 through May, 
2023. HRG surveys would be conducted throughout the 12-month project 
timeframe. Activities associated with the construction of the project 
are described in more detail below.

Cable Laying

    Cable burial operations will occur both in the SFWF for the inter-
array cables connecting the WTGs to the OSS and in the SFEC for the 
cables carrying power from the OSS to land. Inter-array cables will 
connect the 15 WTGs to the OSS. A single offshore export cable will 
connect the OSS to the shore. The offshore export and inter-array 
cables will be buried beneath the seafloor at a target depth of up to 
1.2-2.8 m (4-6 ft). Installation of the offshore export cable is 
anticipated to last approximately 2 months. The estimated installation 
time for the inter-array cables is approximately 4 months. All cable 
burial operations will follow installation of the monopile foundations, 
as the foundations must be in place to provide connection points for 
the export cable and inter-array cables. Installation days are not 
continuous and do not include equipment preparation or down time that 
may result from weather or maintenance. Equipment preparation is not 
considered a source of marine mammal disturbance or harassment.
    Some dredging may be required prior to cable laying due to the 
presence of sand waves. The upper portions of sand waves may be removed 
via mechanical or hydraulic means in order to achieve the proper burial 
depth below the stable sea bottom. The majority of the export and 
inter-link cable is expected to be installed using simultaneous lay and 
bury via jet plowing. Jet plowing entails the use of an adjustable 
blade, or plow, which rests on the sea floor and is towed by a surface 
vessel. The plow creates a narrow trench at the desired depth, while 
water jets fluidize the sediment within the trench. The cable is then 
fed through the plow and is laid into the trench as it moves forward. 
The fluidized sediments then settle back down into the trench and bury 
the cable. The majority of the inter-array cable is also expected to be 
installed via jet plowing after the cable has been placed on the 
seafloor. Other methods, such as mechanical plowing or trenching, may 
be needed in areas of coarser or more consolidated sediment, rocky 
bottom, or other difficult conditions in order to ensure a proper 
burial depth. The jet plowing tool may be based from a seabed tractor 
or a sled deployed from a vessel. A mechanical plow is also deployed 
from a vessel. More information on cable laying associated with the 
proposed project is provided in South Fork Wind's Construction and 
Operations Plan (SFWF COP; South Fork Wind, 2020). As the only 
potential impacts from these activities is sediment suspension, the 
potential for take of marine mammals to result from these activities is 
so low as to be discountable and South Fork Wind did not request, and 
NMFS does not propose to authorize, any takes associated with cable 
laying. Therefore, cable laying activities are not analyzed further in 
this document.

Construction-Related Vessel Activity

    During construction of the project, South Fork Wind anticipates 
that an average of approximately 5-10 vessels will operate during a 
typical work day in the SFWF and along the SFEC. Many of these vessels 
will remain in the SFWF or SFEC for days or weeks at a time, 
potentially making only infrequent trips to port for bunkering and 
provisioning, as needed. The actual number of vessels involved in the 
project at one time is highly dependent on the project's final 
schedule, the final design of the project's components, and the 
logistics needed to ensure compliance with the Jones Act, a Federal law 
that regulates maritime commerce in the United States.
    Existing vessel traffic in the vicinity of the project area 
southeast of Rhode Island is relatively high and marine mammals in the 
area are expected to be habituated to vessel noise. In addition, 
construction vessels would be stationary on site for significant 
periods of time and the large vessels would travel to and from the site 
at relatively low speeds. Project-related vessels would be required to 
adhere to several mitigation measures designed to reduce the potential 
for marine mammals to be struck by vessels associated with the project; 
these measures are described further below (see Proposed Mitigation). 
As part of various construction related activities, including cable 
laying and construction material delivery, dynamic positioning 
thrusters may be utilized to hold vessels in position or move slowly. 
Sound produced through use of dynamic positioning thrusters is similar 
to that produced by transiting vessels, and dynamic positioning 
thrusters are typically operated either in a similarly predictable 
manner or used for short durations around stationary activities. Sound 
produced by dynamic positioning thrusters would be preceded by, and 
associated with, sound from ongoing vessel noise and would be similar 
in nature; thus, any marine mammals in the vicinity of the activity 
would be aware of the vessel's presence, further reducing the potential 
for startle or flight responses on the part of marine mammals. 
Construction-related vessel activity, including the use of dynamic 
positioning thrusters, is not expected to result in take of marine 
mammals and South Fork Wind did not request, and NMFS does not propose 
to authorize, any takes associated with construction related vessel 
activity. Accordingly, these activities are not analyzed further in 
this document.

Installation of WTGs and OSS

    Monopiles are the only foundation type proposed for the project. A 
monopile is a single, hollow cylinder fabricated from steel that is 
secured in the seabed. The 16 monopiles installed to support the 15 WTG 
and single OSS would be 11.0 m (33.0 ft) in diameter, up to 95 m (311.7 
ft) in length and driven to a maximum penetration depth of 50 m (164 
ft). A schematic diagram showing potential heights and dimensions of 
the various components of a monopile foundation are shown in Figure 
3.1-2 of the SFWF COP (South Fork Wind, 2020), available online at: 
https://www.boem.gov/renewable-energy/state-activities/south-fork.
    The monopile foundations would be installed by one or two heavy 
lift or jack-up vessels. The main installation vessel(s) will likely 
remain at the SFWF during the installation phase (approximately 30 
days) and transport vessels, tugs, and/or feeder barges would provide a 
continuous supply of foundations to the SFWF. If appropriate vessels 
are available, the foundation

[[Page 8494]]

components could be picked up directly in the marshalling port by the 
main installation vessel(s).
    Within the SFWF, the main installation vessel would upend the 
monopile with a crane, and place it in the gripper frame, before 
lowering the monopile to the seabed. The gripper frame, depending upon 
its design, may be placed on the seabed scour protection materials to 
stabilize the monopile's vertical alignment before and during piling. 
Scour protection is included to protect the foundation from scour 
development, which is the removal of the sediments near structures by 
hydrodynamic forces, and consists of the placement of stone or rock 
material around the foundation. The scour protection would consist of 
engineered rock placed around the base of each monopole in a 68 m (222 
ft) diameter circle, using either a fallpipe vessel or stone dumping 
vessel. Once the monopile is lowered to the seabed, the crane hook 
would be released, and the hydraulic hammer would be picked up and 
placed on top of the monopile.
    All monopoles would be installed with an impact hammer. Impact pile 
driving entails the use of a hammer that utilizes a rising and falling 
piston to repeatedly strike a pile and drive it into the ground. Using 
a crane, the installation vessel would upend the monopile, place it in 
the gripper frame, and then lower the monopile to the seabed. The 
gripper frame would stabilize the monopile's vertical alignment before 
and during piling. Once the monopile is lowered to the seabed, the 
crane hook would be released and the hydraulic hammer would be picked 
up and placed on top of the monopile. A temporary steel cap called a 
helmet would be placed on top of the pile to minimize damage to the 
head during impact driving. The largest hammer South Fork Wind expects 
to use for driving monopiles produces up to 4,000 kilojoules (kJ) of 
energy (however, required energy may ultimately be far less than 4,000 
kJ). As described in the Proposed Mitigation section below, South Fork 
Wind would utilize a sound attenuation device (e.g., bubble curtain) 
during all impact pile driving.
    The intensity (i.e., hammer energy level) of impact pile driving 
would be gradually increased based on the resistance that is 
experienced from the sediments. The strike rate for the monopile 
foundations is estimated to be 36 strikes per minute. Two pile driving 
scenarios (for 16 11 m piles), were considered for SFWF (Table 1). The 
standard pile driving scenario would require an estimated 4,500 strikes 
for the pile to reach the target penetration depth, with an average 
installation time of 140 minutes for one pile. In the event that a pile 
location presents denser substrate conditions and requires more strikes 
to reach the target penetration depth, a difficult-to-drive pile 
scenario was considered, in which 8,000 strikes and approximately 250 
minutes would be required to install 1 pile.
    Impact pile driving activities at SFWF will take place between May 
1, 2022 and December 31, 2022. There are two piling scenarios that are 
considered possible within the current engineering design. The standard 
scenario assumes that a pile is driven every other day such that 16 
monopiles piles would be installed over a 30-day period. A more 
aggressive schedule is considered for the maximum design scenario in 
which six piles are driven in a week (7 days) such that the 16 piles 
are installed over a 20-day period. Only one pile would be driven per 
24 hours (hrs), irrespective of the selected scenario. Please see Table 
1 for a summary of impact pile driving activity.

Installation and Removal of Temporary Cofferdam

    Before cable-laying HDD begins, a temporary cofferdam may be 
installed at the endpoint of the HDD starting point, where the SFEC 
conduit exits from the seabed. The cofferdam would be less than 600 m 
(1,969 ft) offshore from the mean high water line (MHWL), in 7.6 to 
12.2 m (25 to 40 ft) water depth, depending on the final siting point. 
The cofferdam, up to 22.9 m (75 ft) by 7.7 m (25 ft), would serve as 
containment for the drilling returns during the HDD installation to 
keep the excavation free of debris and silt. The cofferdam may be 
installed as either a sheet pile structure into the seafloor or a 
gravity cell structure placed on the seafloor using ballast weight. 
Installation of a gravity cell cofferdam would not result in incidental 
take of marine mammals and is, therefore, not analyzed further in this 
document. Installation of the 19.5 m (64 ft) long, 0.95 centimeters 
(cm) (0.375 inches (in)) thick Z-type sheet pile cofferdam and drilling 
support would be conducted from an offshore barge anchored near the 
cofferdam.
    If the potential cofferdam is installed using sheet pile, a 
vibratory hammer will be used to drive the sidewalls and endwalls into 
the seabed to a depth of approximately 1.8 m (6 ft); sections of the 
shoreside endwall will be driven to a depth of up to 9 m (30 ft) to 
facilitate the HDD entering underneath the endwall. Cofferdam removal 
would consist of pile removal using a vibratory hammer, after HDD 
operations are complete and the conduit is installed (see Table 1 for a 
summary of potential vibratory pile driving activity).
    Vibratory hammering is accomplished by rapidly alternating (~250 
Hertz (Hz)) forces to the pile. A system of counter-rotating eccentric 
weights powered by hydraulic motors are designed such that horizontal 
vibrations cancel out, while vertical vibrations are transmitted into 
the pile. The vibrations produced cause liquefaction of the substrate 
surrounding the pile, enabling the pile to be driven into the ground 
using the weight of the pile plus the impact hammer. If the gravity 
cell installation technique is not practicable, South Fork Wind 
anticipates that any vibratory pile driving of sheet piles would occur 
for a total of 36 hrs (18 hrs for installation, 18 hrs for removal).
    The source levels and source characteristics associated with 
vibratory driving would be generally similar to those produced through 
other concurrent use of vessels and related construction equipment. Any 
elevated noise levels produced through vibratory driving are expected 
to be of relatively short duration, and with low source level values. 
However, it is possible that if marine mammals are exposed to sound 
from vibratory pile driving, they may alert to the sound and 
potentially exhibit a behavioral response that rises to the level of 
take.
    Installation of the Z-type sheet piles would occur primarily in 
daylight; however, it is possible that vibratory pile driving may 
continue past sunset if required by the construction schedule.

                          Table 1--Summary of Pile Driving Activities for SFWF and SFEC
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    Pile driving                            Number of                                           Number of piling
       method             Pile size           piles         Strikes/pile      Duration/pile           days
----------------------------------------------------------------------------------------------------------------
Impact.............  11 m monopile.....              16  Standard pile:     Standard pile:     Standard
                                                          4,500.             140 min.           scenario: 30.
                                                         Difficult pile:    Difficult pile:    Maximum scenario:
                                                          8,000.             250 min.           20.

[[Page 8495]]

 
Vibratory..........  19.5 m long/0.95              * 80  .................  18 hours.........  Installation: 1-
                      cm thick Sheet                                        18 hours.........   3.
                      pile.                                                                    Removal: 1-3.
----------------------------------------------------------------------------------------------------------------
* Approximation; the actual number will be based on final engineering design.

High-Resolution Geophysical Surveys

    The HRG survey activities would be supported by vessels of 
sufficient size to accomplish the survey goals in each of the specified 
survey areas. Up to four vessels may work concurrently throughout the 
area considered in this proposal. HRG surveys would occur throughout 
the 12-month period of effectiveness for the proposed IHA. HRG 
equipment will either be deployed from remotely operated vehicles 
(ROVs) or mounted to or towed behind the survey vessel at a typical 
survey speed of approximately 4.0 knots (kn) (7.4 km) per hour. The 
geophysical survey activities proposed by South Fork Wind would include 
the following:
     Shallow Penetration Sub-bottom Profilers (SBPs; Compressed 
High-Intensity Radiated Pulses (CHIRPs)) to map the near-surface 
stratigraphy (top 0 to 5 m (0 to 16 ft) of sediment below seabed). A 
CHIRP system emits sonar pulses that increase in frequency over time. 
The pulse length frequency range can be adjusted to meet project 
variables. These are typically mounted on the hull of the vessel or 
from a side pole.
     Medium penetration SBPs (Boomers) to map deeper subsurface 
stratigraphy as needed. A boomer is a broad-band sound source operating 
in the 3.5 Hz to 10 kHz frequency range. This system is typically 
mounted on a sled and towed behind the vessel.
     Medium penetration SBPs (Sparkers) to map deeper 
subsurface stratigraphy as needed. A sparker creates acoustic pulses 
from 50 Hz to 4 kHz omni-directionally from the source that can 
penetrate several hundred meters into the seafloor. These are typically 
towed behind the vessel with adjacent hydrophone arrays to receive the 
return signals.
     Parametric SBPs, also called sediment echosounders, for 
providing high density data in sub-bottom profiles that are typically 
required for cable routes, very shallow water, and archaeological 
surveys. These are typically mounted on the hull of the vessel or from 
a side pole.
     Ultra-short Baseline (USBL) Positioning and Global 
Acoustic Positioning System (GAPS) to provide high accuracy ranges to 
track the positions of other HRG equipment 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.
     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.
     Seafloor imaging (sidescan sonar) for seabed sediment 
classification purposes, to identify natural and man-made acoustic 
targets resting on the bottom as well as any anomalous features. 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.
    Table 2 identifies all the representative survey equipment that 
operate below 180 kilohertz (kHz) (i.e., at frequencies that are 
audible and have the potential to disturb marine mammals) that may be 
used in support of planned geophysical survey activities, and are 
likely to be detected by marine mammals given the source level, 
frequency, and beamwidth of the equipment. The operational frequencies 
for MBES and Sidescan Sonar that would be used for these surveys are 
greater than 180 kHz, outside the general hearing range of marine 
mammals likely to occur in SFWF and SFEC. Parametric sub-bottom 
profilers operate at high frequencies with narrow beamwidths, resulting 
in Level A harassment and Level B harassment threshold isopleth 
distances less than 4 m. No harassment exposures can be reasonably 
expected from the operation of these sources; therefore, the Innomar 
parametric SBPs were not carried forward in the application analysis. 
USBLs are instruments that are used to locate the position(s) of other 
HRG equipment; the sources characteristics and functionality of USBLs 
are not expected to result in Level A harassment or Level B harassment. 
These equipment types are, therefore, not considered further in this 
notice. For discussion of acoustic terminology, please see the 
Potential Effects of Specified Activities on Marine Mammals and their 
Habitat and Estimated Take sections.
    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. Selection of equipment combinations is based on 
specific survey objectives.

                                                 Table 2--Summary of Representative HRG Survey Equipment
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                  Typical
                                                                             Operating      Source       Source     Beamwidth      pulse        Pulse
          HRG equipment  category                Specific HRG equipment      frequency    level  (dB   level  (dB   (degrees)     duration    repetition
                                                                            range (kHz)      rms)       0-peak)                     (ms)         rate
--------------------------------------------------------------------------------------------------------------------------------------------------------
Shallow Sub-bottom Profilers...............  ET 216 (2000DS or 3200 top            2-16          195            -           24           20            6
                                              unit).                                2-8
                                             ET 424.......................         4-24          176            -           71          3.4            2
                                             ET 512.......................       0.7-12          179            -           80            9            8

[[Page 8496]]

 
                                             GeoPulse 5430A...............         2-17          196            -           55           50           10
                                             TB Chirp III--TTV 170........          2-7          197            -          100           60           15
Medium Sub-bottom Profilers................  AA, Dura-spark UHD (400 tips,      0.3-1.2          203          211         Omni          1.1            4
                                              500 J) \1\.
                                             AA, Dura-spark UHD (400+400)       0.3-1.2          203          211         Omni          1.1            4
                                              \1\.
                                             GeoMarine, Geo-Source or             0.4-5          203          211         Omni          1.1            2
                                              similar dual 400 tip sparker
                                              (<=800 J) \1\.
                                             GeoMarine Geo-Source 200 tip       0.3-1.2          203          211         Omni          1.1            4
                                              light weight sparker (400 J)
                                              \1\.
                                             GeoMarine Geo-Source 200-400       0.3-1.2          203          211         Omni          1.1            4
                                              tip freshwater sparker (400
                                              J) \1\.
                                             AA, triple plate S[dash]Boom         0.1-5          205          211           80          0.6            4
                                              (700-1,000 J) \2\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
- = not applicable; NR = not reported; AA = Applied Acoustics; dB = decibel; ET = EdgeTech; J = joule; Omni = omnidirectional source.
\1\ The Dura-spark measurements and specifications provided in Crocker and Fratantonio (2016) were used for all sparker systems proposed for the survey.
  The data provided in Crocker and Fratantonio (2016) represent the most applicable data for similar sparker systems with comparable operating methods
  and settings when manufacturer or other reliable measurements are not available.
\2\ Crocker and Fratantonio (2016) provide S-Boom measurements using two different power sources (CSP-D700 and CSP-N). The CSP-D700 power source was
  used in the 700 J measurements but not in the 1,000 J measurements. The CSP-N source was measured for both 700 J and 1,000 J operations but resulted
  in a lower SL; therefore, the single maximum SL value was used for both operational levels of the S-Boom.

    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 IHA 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' Stock Assessment Reports (SARs; 
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' 
website (www.fisheries.noaa.gov/find-species).
    There are 36 marine mammal species that could potentially occur in 
the proposed project area and that are included in Table 16 of the IHA 
application. However, the temporal and/or spatial occurrence of 20 of 
these species is such that take is not expected to occur, and they are 
therefore not discussed further beyond the explanation provided here. 
The following species are not expected to occur in the project area due 
to the location of preferred habitat outside the SFWF and SFEC, based 
on the best available information: The beluga whale (Delphinapterus 
leucas), northern bottlenose whale (Hyperoodon ampullatus), killer 
whale (Orcinus orca), pygmy killer whale (Feresa attenuata), false 
killer whale (Pseudorca crassidens), melon-headed whale (Peponocephala 
electra), the pygmy sperm whale (Kogia breviceps), Cuvier's beaked 
whale (Ziphius cavirostris), Mesplodont beaked whales (spp.), short-
finned pilot whale (Globicephala macrorhynchus), pantropical spotted 
dolphin (Stenella attenuata), Fraser's dolphin (Lagenodelphis hosei), 
white-beaked dolphin (Lagenorhynchus albirostris), rough-toothed 
dolphin (Steno bredanensis), Clymene dolphin (Stenella clymene), 
spinner dolphin (Stenella longirostris), and striped dolphin (Stenella 
coeruleoalba). The following species may occur in the project area, but 
at such low densities that take is not anticipated: Hooded seal 
(Cystophora cristata) and harp seal (Pagophilus groenlandica). There 
are two pilot whale species (long-finned and short-finned (Globicephala 
macrorhynchus)) with distributions that overlap in the latitudinal 
range of the SFWF (Hayes et al., 2020; Roberts et al., 2016). Because 
it is difficult to differentiate between the two species at sea, 
sightings, and thus the densities calculated from them, are generally 
reported together as Globicephala spp. (Hayes et al., 2020; Roberts et 
al., 2016). However, based on the best available information, short-
finned pilot whales occur in habitat that is both further offshore on 
the shelf break and further south than the project area (Hayes et al., 
2020). Therefore, NMFS assumes that any take of pilot whales would be 
of long-finned pilot whales.
    In addition, the Florida manatee (Trichechus manatus) may be found 
in the coastal waters of the Survey Area. However, Florida manatees are 
managed by the U.S. Fish and Wildlife Service and are not considered 
further in this document.
    Between October 2011 and June 2015 a total of 76 aerial surveys 
were conducted throughout the MA and RI/MA Wind Energy Areas (WEAs) 
(the SFWF is contained within the RI/MA WEA along with several other 
offshore renewable energy lease areas). Between November 2011 and March 
2015, Marine Autonomous Recording Units (MARU; a type of static passive 
acoustic monitoring (PAM) recorder) were deployed at nine sites in the 
MA and RI/MA WEAs. The goal of the study was to collect visual and 
acoustic baseline data on distribution, abundance, and temporal 
occurrence patterns of marine mammals (Kraus et al., 2016). The lack of 
detections of any of the species listed above reinforces the fact that 
these species are not expected to occur in the project area. As these 
species are not expected to occur in the project area during the 
proposed activities, NMFS does not propose to authorize take of these 
species and they are not discussed further in this document.
    NMFS expects that the 16 species listed in Table 3 will potentially 
occur

[[Page 8497]]

in the project area and may be taken as a result of the proposed 
project. Table 3 summarizes information related to the population or 
stock, including regulatory status under the MMPA and Endangered 
Species Act (ESA) and potential biological removal (PBR), where known. 
For taxonomy, NMFS follows the Committee on Taxonomy (2020). PBR is 
defined by the MMPA as the maximum number of animals, not including 
natural mortalities, that may be removed from a marine mammal stock 
while allowing that stock to reach or maintain its optimum sustainable 
population (as described in NMFS' SARs). While no mortality is 
anticipated or authorized here, PBR is included here as a gross 
indicator 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' stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS' U.S. Atlantic SARs. All values presented in Table 3 are the most 
recent available at the time of publication and are available in the 
draft 2020 Atlantic SARs, available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

                 Table 3--Marine Mammals Known To Occur in the Project Area That May Be Affected by South Fork Wind's Proposed Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                  MMPA and ESA       Stock abundance (CV,                             Occurrence and
    Common name (scientific name)              Stock            status; strategic     Nmin, most recent      PBR \3\   Annual M/      seasonality  in
                                                                    (Y/N) \1\       abundance survey) \2\                SI \3\        project area
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               Toothed whales (Odontoceti)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sperm whale (Physeter macrocephalus)  North Atlantic.........  E; Y                4,349 (0.28; 3,451;            3.9          0  Rare.
                                                                                    2016).
Long-finned pilot whale               W North Atlantic.......  --; N               39,215 (0.3; 30,627;           306         21  Rare.
 (Globicephala melas).                                                              2016).
Atlantic spotted dolphin (Stenella    W North Atlantic.......  --; N               39,921 (0.27; 32,032;          320          0  Rare.
 frontalis).                                                                        2016).
Atlantic white-sided dolphin          W North Atlantic.......  --; N               93,233 (0.71; 54,443;          544         26  Common year round.
 (Lagenorhynchus acutus).                                                           2016).
Bottlenose dolphin (Tursiops          W North Atlantic,        --; N               62,851 (0.23; 51,914;          519         28  Common year round.
 truncatus).                           Offshore.                                    2019).
Common dolphin (Delphinus delphis)..  W North Atlantic.......  --; N               172,974 (0.21; 145,216;      1,452        399  Common year round.
                                                                                    2016).
Risso's dolphin (Grampus griseus)...  W North Atlantic.......  --; N               35,493 (0.19; 30,298;          303       54.3  Rare.
                                                                                    2016).
Harbor porpoise (Phocoena phocoena).  Gulf of Maine/Bay of     --; N               95,543 (0.31; 74,034;          851        217  Common year round.
                                       Fundy.                                       2019).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                Baleen whales (Mysticeti)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale (Balaenotpera musculus)..  W North Atlantic.......  E; Y                ukn (unk; 402; 2008)...        0.8          0  Rare.
North Atlantic right whale            W North Atlantic.......  E; Y                412 (0; 418; 2018).....        0.8       18.6  Year round in
 (Eubalaena glacialis).                                                                                                            continental shelf and
                                                                                                                                   slope waters, occur
                                                                                                                                   seasonally.
Humpback whale (Megaptera             Gulf of Maine..........  --; N               1,393 (0.15; 1,375;             22         58  Common year round.
 novaeangliae).                                                                     2016).
Fin whale (Balaenoptera physalus)...  W North Atlantic.......  E; Y                6,802 (0.24; 5,573;             11       2.35  Year round in
                                                                                    2016).                                         continental shelf and
                                                                                                                                   slope waters, occur
                                                                                                                                   seasonally.
Sei whale (Balaenoptera borealis)...  Nova Scotia............  E; Y                6,292 (1.02; 3,098 ;           6.2        1.2  Year round in
                                                                                    2016).                                         continental shelf and
                                                                                                                                   slope waters, occur
                                                                                                                                   seasonally.
Minke whale (Balaenoptera             Canadian East Coast....  --; N               21,968 (0.31; 17,002;          170       10.6  Year round in
 acutorostrata).                                                                    2016).                                         continental shelf and
                                                                                                                                   slope waters, occur
                                                                                                                                   seasonally.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                Earless seals (Phocidae)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gray seal \4\ (Halichoerus grypus)..  W North Atlantic.......  --; N               27,131 (0.19; 23,158;        1,389      4,729  Common year round.
                                                                                    2016).
Harbor seal (Phoca vitulina)........  W North Atlantic.......  --; N               75,834 (0.15; 66,884;        2,006        350  Common year round.
                                                                                    2012).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or
  designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR (see
  footnote 3) 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\ Stock abundance as reported in NMFS marine mammal stock assessment reports (SAR) except where otherwise noted. SARs available online at:
  www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments. CV is coefficient of variation; Nmin is the minimum estimate
  of stock abundance. In some cases, CV is not applicable. For certain stocks, abundance estimates are actual counts of animals and there is no
  associated CV. The most recent abundance survey that is reflected in the abundance estimate is presented; there may be more recent surveys that have
  not yet been incorporated into the estimate. All values presented are from the draft 2020 Atlantic SARs.
\3\ Potential biological removal, defined by the MMPA as the maximum number of animals, not including natural mortalities, that may be removed from a
  marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population size (OSP). Annual Mortality/Serious Injury (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 2020 Atlantic SARs.
\4\ NMFS stock abundance and PBR estimates apply to U.S. population only, actual stock abundance is approximately 505,000.

    Four marine mammal species that are listed under ESA may be present 
in the project area and may be taken incidental to the proposed 
activity: The North Atlantic right whale, fin whale, sei whale, and 
sperm whale.
    Below is a description of the species that are likely to occur in 
the project area and are thus expected to potentially

[[Page 8498]]

be taken by the proposed activities. For the majority of species 
potentially present in the specific geographic region, NMFS has 
designated only a single generic stock (e.g., ``western North 
Atlantic'') for management purposes. This includes the ``Canadian east 
coast'' stock of minke whales, which includes all minke whales found in 
U.S. waters and is also a generic stock for management purposes. For 
humpback and sei whales, NMFS defines stocks on the basis of feeding 
locations, i.e., Gulf of Maine and Nova Scotia, respectively. However, 
references to humpback whales and sei whales in this document refer to 
any individuals of the species that are found in the specific 
geographic region. Any biologically important areas (BIAs) that overlap 
spatially with the project area are addressed in the species sections 
below.

North Atlantic Right Whale

    The North Atlantic right whale ranges from calving grounds in the 
southeastern United States to feeding grounds in New England waters and 
into Canadian waters (Hayes et al., 2020). Surveys have demonstrated 
the existence of seven areas where North Atlantic right whales 
congregate seasonally, including north and east of the proposed project 
area in Georges Bank, off Cape Cod, and in Massachusetts Bay (Hayes et 
al., 2020). In the late fall months (e.g. October), North Atlantic 
right whales are generally thought to depart from the feeding grounds 
in the North Atlantic and move south along a migratory corridor to 
their calving grounds off Georgia and Florida. However, ongoing 
research indicates our understanding of their movement patterns remains 
incomplete (Davis et al., 2017; Oleson et al., 2020). A review of 
passive acoustic monitoring data from 2004 to 2014 throughout the 
western North Atlantic demonstrated nearly continuous year-round North 
Atlantic right whale presence across their entire habitat range (for at 
least some individuals), including in locations previously thought of 
as migratory corridors, suggesting that not all of the population 
undergoes a consistent annual migration (Davis et al., 2017). Acoustic 
monitoring data from 2004 to 2014 indicated that the number of North 
Atlantic right whale vocalizations detected in the proposed project 
area were relatively constant throughout the year, with the exception 
of August through October when detected vocalizations showed an 
apparent decline (Davis et al., 2017). Shifts in habitat use have also 
been observed. During visual surveys conducted from 2012 to 2016, fewer 
North Atlantic right whales were detected in the Great South Channel 
(NMFS unpublished data) and the Bay of Fundy (Davies et al., 2019), 
while the number of individuals using Cape Cod Bay in the spring 
increased (Mayo et al., 2018). Cole et al. (2013) provided survey 
evidence that North Atlantic right whales were absent from the well-
documented central Gulf of Maine winter habitat. Although present to 
some extent year round in the region south of Martha's Vineyard and 
Nantucket Islands (Oleson et al., 2020), North Atlantic right whales 
have recently been observed feeding in large numbers in this area in 
the winter (Leiter et al., 2017), which is outside of the 2016 
Northeastern U.S. Foraging Area Critical Habitat. In addition, North 
Atlantic right whale distribution has shifted northward into the Gulf 
of St. Lawrence (Simard et al., 2019), where acoustic and visual survey 
effort indicate North Atlantic right whale presence in late spring 
through the early fall (Cole et al., 2016; Khan et al., 2016, 2018; 
Oleson et al. 2020). Observations of these transitions in North 
Atlantic right whale habitat use, variability in seasonal presence in 
identified core habitats, and utilization of habitat outside of 
previously focused survey effort prompted the formation of a NMFS' 
Expert Working Group, which identified current data collection efforts, 
data gaps, and provided recommendations for future survey and research 
efforts (Oleson et al., 2020).
    The western North Atlantic population demonstrated overall growth 
of 2.8 percent per year between 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 100 percent probability 
of a decline from 2011 to 2018 of just over two percent per year (Pace 
et al., 2017). Between 1990 and 2017, calving rates varied 
substantially, with low calving rates coinciding with all three periods 
of decline or no growth (Pace et al., 2017). On average, North Atlantic 
right whale calving rates are estimated to be roughly one third that of 
southern right whales (Eubalaena australis) (Hayes et al., 2020), which 
are increasing in abundance (NEFSC 2015). The current best estimate of 
population abundance for the North Atlantic right whale is 412 
individuals (Hayes et al., 2020).
    In addition, elevated North Atlantic right whale mortalities have 
occurred since June 7, 2017 along the U.S. and Canadian coast. As of 
January 2021, a total of 32 confirmed dead stranded whales (21 in 
Canada; 11 in the United States) and 14 serious injury (including 
entanglement and vessel strike) cases have been documented. Full 
necropsies have been conducted on 20 of the dead North Atlantic right 
whales and, in the 18 cases for which a preliminary cause of death 
could be determined, 8 and 10 were attributed to entanglement and 
vessel strike, respectively. This event has been declared an Unusual 
Mortality Event (UME); the leading cause of death for this UME is 
``human interaction'', specifically from entanglements or vessel 
strikes. More information is available online at: 
www.fisheries.noaa.gov/national/marine-life-distress/2017-2020-north-atlantic-right-whale-unusual-mortality-event.
    During the aerial surveys conducted in the RI/MA and MA WEAs from 
2011-2015, the highest number of North Atlantic right whale sightings 
occurred in March (n=21), with sightings also occurring in December 
(n=4), January (n=7), February (n=14), and April (n=14), and no 
sightings in any other months (Kraus et al., 2016). There was not 
significant variability in sighting rate among years, indicating 
consistent annual seasonal use of the area by North Atlantic right 
whales. Despite the lack of visual detection, North Atlantic right 
whales were acoustically detected in 30 out of the 36 recorded months 
(Kraus et al., 2016). While density data from Roberts et al. (2020) 
confirm that the highest density of North Atlantic right whales in the 
project area occurs in March, it is clear that North Atlantic right 
whales are present in or near the project area throughout the year, 
particularly south of Martha's Vineyard and Nantucket Islands, and that 
habitat use is changing (Leiter et al., 2017; Stone et al., 2017; 
Oleson et al., 2020). The proposed project area is part of an important 
migratory area for North Atlantic right whales; this migratory area is 
comprised of the waters of the continental shelf offshore the East 
Coast of the United States and extends from Florida through 
Massachusetts. Aerial surveys conducted in and near the project area 
from 2011-2015 documented a total of six instances of feeding behavior 
by North Atlantic right whales (Kraus et al., 2016). Finally, the 
project area is located within the North Atlantic right whale migratory 
corridor Biologically Important Area (BIA), which is applicable 
November 1 through December 31, 2021 and March 1, 2022 through April 
31, 2022 and extends from Florida to Massachusetts (LeBreque et al., 
2015).
    NMFS' regulations at 50 CFR 224.105 designated nearshore waters of 
the Mid-Atlantic Bight as Mid-Atlantic U.S.

[[Page 8499]]

Seasonal Management Areas (SMA) for North Atlantic right whales in 
2008. SMAs were developed to reduce the threat of collisions between 
ships and North Atlantic right whales around their migratory route and 
calving grounds. The Block Island SMA, which is active from November 1 
through April 30 each year, overlaps with the project area.

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 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). In the western North Atlantic, 
humpback whales feed over a broad geographic range encompassing the 
eastern coast of the United States (including the Gulf of Maine), 
Scotian Shelf, Gulf of St. Lawrence, Newfoundland/Labrador, and Western 
Greenland (Katona and Beard 1990). Spatial and genetic mixing occurs 
when humpback whales from most of these feeding areas migrate to the 
West Indies in the winter to mate and calve. The Gulf of Maine feeding 
stock population abundance is estimated at 1,393 individuals, or 
approximately 11 percent of the West Indies DPS.
    In New England waters, feeding is the principal activity of 
humpback whales, and their distribution in this region has been largely 
correlated to abundance of prey species, although behavior and 
bathymetry are factors influencing foraging strategy (Payne et al., 
1986, 1990). 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 (Hayes et al., 2020).
    Kraus et al. (2016) observed humpbacks in the RI/MA & MA Wind 
Energy Areas (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. study (2016). 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 MA WEA year-round, with the 
highest rates of acoustic detections in the winter and spring (Kraus et 
al., 2016). Other sightings of note include 46 sightings of humpback 
whales in the New York-New Jersey Harbor Estuary documented from 2011-
2016 (Brown et al., 2017). Since January 2016, elevated humpback whale 
mortalities have occurred along the Atlantic coast from Maine to 
Florida, leading to the declaration of an UME. Partial or full necropsy 
examinations have been conducted on approximately half of the 140 known 
cases. Of the whales examined, about 50 percent had evidence of human 
interaction, either ship strike or entanglement. While a portion of the 
whales have shown evidence of pre-mortem vessel strike, this finding is 
not consistent across all whales examined and 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. Three 
previous UMEs involving humpback whales have occurred since 2000, in 
2003, 2005, and 2006. More information is available at: 
www.fisheries.noaa.gov/national/marine-life-distress/2016-2019-humpback-whale-unusual-mortality-event-along-atlantic-coast. A BIA for 
humpback whales for feeding has been designated northeast of the lease 
area and is applicable from March through December (LeBreque et al., 
2015).

Fin Whale

    Fin whales are common in waters of the U.S. Atlantic Exclusive 
Economic Zone (EEZ), principally from Cape Hatteras northward (Hayes et 
al., 2020). Fin whales are present north of 35-degree latitude in every 
season and are broadly distributed throughout the western North 
Atlantic for most of the year, though densities vary seasonally (Hayes 
et al., 2020). In this region, fin whales are the dominant large 
cetacean species during all seasons, having the largest standing stock, 
the largest food requirements, and therefore the largest influence on 
ecosystem processes of any cetacean species (Hain et al., 1992; Kenney 
et al., 1997). It is likely that fin whales occurring in the U.S. 
Atlantic EEZ undergo migrations into Canadian waters, open-ocean areas, 
and perhaps even subtropical or tropical regions (Edwards et al., 
2015).
    New England waters represent a major feeding ground for fin whales; 
a feeding BIA for the species exists just west of the proposed project 
area, stretching from just south of the eastern tip of Long Island to 
south of the western tip of Martha's South Fork (LeBreque et al., 
2015). In aerial surveys conducted from 2011-2015 in the project area, 
sightings occurred in every season with the greatest numbers of 
sightings during the spring (n=35) and summer (n=49) months (Kraus et 
al., 2016). Despite much lower sighting rates during the winter, 
confirmed acoustic detections of fin whales recorded on a hydrophone 
array in the project area from 2011-2015 occurred throughout the year; 
however, due to acoustic detection ranges in excess of 200 km, the 
detections do not confirm that fin whales were present in the project 
area during that time (Kraus et al., 2016).

Sei Whale

    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. The southern portion of the 
stock's range during spring and summer includes the Gulf of Maine and 
Georges Bank, a region now considered a portion of a feeding BIA for 
sei whales from May through November (LeBreque et al., 2015). 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 (Hayes et al., 2020). Sei whales 
often occur in shallower waters to feed. In aerial

[[Page 8500]]

surveys conducted from 2011-2015 in the project area sightings of sei 
whales occurred between March and June, with the greatest number of 
sightings in May (n=8) and June (n=13), and no sightings from July 
through January (Kraus et al., 2016).

Minke Whale

    Minke whales occur in temperate, tropical, and high-latitude 
waters. The Canadian East Coast stock can be found in the area from the 
western half of the Davis Strait (45[deg] W) to the Gulf of Mexico 
(Hayes et al., 2020). 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 (Hayes et al., 2020). In aerial 
surveys conducted from 2011-2015 in the project area, sightings of 
minke whales occurred between March and September, with the greatest 
number of sightings occurring in May (n=38) and no sightings from 
October through February (Kraus et al., 2016). Although they do not 
overlap with the SFWF and SFEC, two minke whale feeding BIAs were 
defined for the southern Gulf of Maine and surrounding waters (<200 m), 
including the waters east of Cape Cod and Nantucket, applicable from 
March through November (LeBreque et al., 2015).
    Since January 2017, elevated minke whale mortalities have occurred 
along the Atlantic coast from Maine through South Carolina, with a 
total of 103 strandings recorded when this document was written. This 
event has been declared a UME. Full or partial necropsy examinations 
were conducted on more than 60 percent of the whales. Preliminary 
findings in several of the whales have shown evidence of human 
interactions or infectious disease, but these findings are not 
consistent across all of the whales examined, so more research is 
needed. More information is available at: 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. EEZ occurs on the 
continental shelf edge, over the continental slope, and into mid-ocean 
regions (Hayes et al., 2020). The basic social unit of the sperm whale 
appears to be the mixed group of adult females with their calves and 
some juveniles of both sexes, normally numbering 20-40 animals in all. 
There is evidence that some social bonds persist for many years 
(Christal et al., 1998). 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. Sperm whales are not expected to be common 
in the project area due to the relatively shallow depths in the project 
area. In aerial surveys conducted from 2011-2015 in the project area 
only four sightings of sperm whales occurred, three in summer and one 
in autumn (Kraus et al., 2016).

Long-Finned Pilot Whale

    Long-finned pilot whales are found from North Carolina and north to 
Iceland, Greenland and the Barents Sea (Hayes et al., 2020). In U.S. 
Atlantic waters the species is distributed principally along the 
continental shelf edge off the northeastern U.S. coast in winter and 
early spring, and in late spring pilot whales move onto Georges Bank 
and into the Gulf of Maine and more northern waters and remain in these 
areas through late autumn (Waring et al., 2016). In aerial surveys 
conducted from 2011-2015 in the project area the majority of pilot 
whale sightings were in spring (n=11); sightings were also documented 
in summer, with no sightings in autumn or winter (Kraus et al., 2016).

Atlantic White-Sided Dolphin

    White-sided dolphins are found in temperate and sub-polar waters of 
the North Atlantic, primarily in continental shelf waters to the 100-m 
depth contour from central West Greenland to North Carolina (Hayes et 
al., 2020). 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 (Payne and Heinemann 1990). Sightings south of Georges Bank, 
particularly around Hudson Canyon, occur year round but at low 
densities. In aerial surveys conducted from 2011-2015 in the project 
area there were sightings of white-sided dolphins in every season 
except winter (Kraus et al., 2016).

Atlantic Spotted Dolphin

    Atlantic spotted dolphins are found in tropical and warm temperate 
waters ranging from southern New England south to Gulf of Mexico and 
the Caribbean to Venezuela (Waring et al., 2014). This stock regularly 
occurs in continental shelf waters south of Cape Hatteras and in 
continental shelf edge and continental slope waters north of this 
region (Waring et al., 2014). There are two forms of this species, with 
the larger ecotype inhabiting the continental shelf, usually found 
inside or near the 200 m isobath (Waring et al., 2014).

Common Dolphin

    The common dolphin is found world-wide in temperate to subtropical 
seas. In the North Atlantic, common dolphins are 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 
(Hayes et al., 2020), but may be found in shallower shelf waters as 
well. Common dolphins are expected to occur in the vicinity of the 
project area in relatively high numbers. Common dolphins were the most 
frequently observed dolphin species in aerial surveys conducted from 
2011-2015 in the project area (Kraus et al., 2016). Sightings peaked in 
the summer between June and August, though there were sightings 
recorded in nearly every month of the year (Kraus et al., 2016).

Bottlenose Dolphin

    There are two distinct bottlenose dolphin morphotypes in the 
western North Atlantic: The coastal and offshore forms (Hayes et al., 
2020). The two morphotypes are genetically distinct based upon both 
mitochondrial and nuclear markers (Hoelzel et al., 1998; Rosel et al., 
2009). The offshore form is distributed primarily along the outer 
continental shelf and continental slope in the Northwest Atlantic Ocean 
from Georges Bank to the Florida Keys, and is the only type that may be 
present in the project area as the northern extent of the range of the 
Western North Atlantic Northern Migratory Coastal

[[Page 8501]]

Stock occurs south of the project area. Bottlenose dolphins are 
expected to occur in the project area in relatively high numbers. They 
were the second most frequently observed species of dolphin in aerial 
surveys conducted from 2011-2015 in the project area, and were observed 
in every month of the year except January and March (Kraus et al., 
2016).

Risso's Dolphin

    Risso's dolphins are distributed worldwide in tropical and 
temperate seas, 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), with 
the range extending outward into oceanic waters in the winter (Payne et 
al., 1984). Risso's dolphins are not expected to be common in the 
project area due to the relatively shallow water depths. In aerial 
surveys conducted from 2011-2015 in the project there were only two 
confirmed sightings of Risso's dolphins, both of which occurred in the 
spring (Kraus et al., 2016).

Harbor Porpoise

    Harbor porpoises occur from the coastline to deep waters (>1800 m; 
Westgate et al. 1998), although the majority of the population is found 
over the continental shelf (Hayes et al., 2020). In the project area, 
only the Gulf of Maine/Bay of Fundy stock of harbor porpoise 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., 2016). 
In aerial surveys conducted from 2011-2015 in the project area, 
sightings of harbor porpoise occurred from November through May, with 
the highest number of detections occurring in April and almost none 
during June-September (Kraus et al., 2016).

Harbor Seal

    The harbor seal is found in all nearshore waters of the North 
Atlantic and North Pacific Oceans and adjoining seas above about 
30[deg] N (Burns, 2009). In the western North Atlantic, harbor seals 
are distributed from the eastern Canadian Arctic and Greenland south to 
southern New England and New York, and occasionally to the Carolinas 
(Hayes et al., 2020). Haulout and pupping sites are located off 
Manomet, MA and the Isles of Shoals, ME (Waring et al., 2016). Based on 
harbor seal sightings reported at sea in shipboard surveys conducted by 
the NMFS Northeast Fisheries Science Center from 1995-2011, harbor 
seals would be expected to occur in the project area from September to 
May (Hayes et al., 2020). Harbor seals are expected to be relatively 
common in the project area. 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, stranded seals have shown clinical signs as far south as 
Virginia, although not in elevated numbers; therefore, the UME 
investigation now encompasses all seal strandings from Maine to 
Virginia. Full or partial necropsy examinations have been conducted on 
some of the seals and samples have been collected for testing. Based on 
tests conducted thus far, the main pathogen found in the seals is 
phocine distemper virus. NMFS is performing additional testing to 
identify any other factors that may be involved in this UME. 
Information on this UME is available online at: www.fisheries.noaa.gov/new-england-mid-atlantic/marine-life-distress/2018-2019-pinniped-unusual-mortality-event-along.

Gray Seal

    There are three major populations of gray seals found in the world: 
Eastern Canada (western North Atlantic stock), northwestern Europe, and 
the Baltic Sea. Gray seals in the project area belong to the western 
North Atlantic stock. The range for this stock is from New Jersey to 
Labrador. Current population trends show that gray seal abundance is 
likely increasing in the U.S. Atlantic EEZ (Hayes et al., 2020). 
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 (Hayes et al., 2020). It is believed that 
recolonization by Canadian gray seals is the source of the U.S. 
population (Hayes et al., 2020). Gray seals are expected to be 
relatively common in the project area. As described above, elevated 
seal mortalities, including gray seals, have occurred across Maine, New 
Hampshire and Massachusetts, and as far south as Virginia, since July 
2018. This event has been declared a UME, with phocine distemper virus 
identified as the main pathogen found in the seals. NMFS is performing 
additional testing to identify any other factors that may be involved 
in this UME.

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, 2019) 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).

[[Page 8502]]

 
Mid-frequency (MF) cetaceans (dolphins,     150 Hz to 160 kHz.
 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) (true    50 Hz to 86 kHz.
 seals).
Otariid pinnipeds (OW) (underwater) (sea    60 Hz to 39 kHz.
 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, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt, 
2013).
    For more details concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information. 
Sixteen marine mammal species (14 cetacean and 2 pinniped (both phocid 
species)) have the reasonable potential to co-occur with the proposed 
activities (Table 3). Of the cetacean species that may be present, six 
are classified as low-frequency cetaceans (i.e., all mysticete 
species), seven are classified as mid-frequency cetaceans (i.e., all 
delphinid species and the sperm whale), and one is classified as a 
high-frequency cetacean (i.e., harbor porpoise).

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

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

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); 
Urick (1983).
    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 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 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 (Urick, 1983). 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 micropascal-
squared second ([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), as is the case for sound produced by the 
pile driving activity considered here. 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

[[Page 8503]]

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 Hz and 50 kHz (ICES 
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 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. Underwater ambient sound in the Atlantic Ocean southeast of 
Rhode Island is comprised of sounds produced by a number of natural and 
anthropogenic sources. Human-generated sound is a significant 
contributor to the ambient acoustic environment in the project 
location. Details of source types are described in the following text.
    Sounds are often considered to fall into one of two general types: 
Impulsive and non-impulsive (defined in the following). 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 impulsive and non-impulsive 
sounds. A signal near a source could be categorized as impulsive, but 
due to propagation effects as it moves farther from the source, the 
signal duration becomes longer (e.g., Greene and Richardson, 1988).
    Impulsive 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. Impulsive 
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-impulsive 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-impulsive sounds can be transient 
signals of short duration but without the essential properties of 
pulses (e.g., rapid rise time). Examples of non-impulsive 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.
    General background information on marine mammal hearing was 
provided previously (see Description of Marine Mammals in the Area of 
the Specified Activities). Here, the potential effects of sound on 
marine mammals are discussed.
    Potential Effects of Underwater Sound--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., 2003; 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. We first 
describe specific manifestations of acoustic effects before providing 
discussion specific to pile driving.
    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 pile driving may result

[[Page 8504]]

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 construction 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--Marine mammals exposed to high-intensity sound, or 
to lower-intensity sound for prolonged periods, can experience hearing 
threshold shift (TS), which NMFS defines as a change, usually an 
increase, in the threshold of audibility at a specified frequency or 
portion of an individual's hearing range above a previously established 
reference level'' (NMFS, 2018). 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 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 or PTS in marine mammals or for further discussion of TTS or PTS 
onset thresholds, please see Southall et al. (2007), Finneran and 
Jenkins (2012), Finneran (2015), and NMFS (2018).
    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,

[[Page 8505]]

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 impulsive 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; 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,b). 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). 
An understanding 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 can 
facilitate the assessment of whether foraging disruptions are likely to 
incur fitness consequences.
    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 North Atlantic 
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

[[Page 8506]]

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 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.
    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 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).
    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

[[Page 8507]]

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.
Potential Acoustic Effects of Proposed Activities
    Acoustic effects on marine mammals during the specified activity 
can occur from impact pile driving, vibratory pile driving/removal, and 
HRG surveys. The effects of underwater noise from construction of the 
SFWF and SFEC have the potential to result in PTS (Level A harassment) 
or disruption of behavioral patterns (Level B harassment) of marine 
mammals in the action area.
    The effects of pile driving on marine mammals are dependent on 
several factors, including the size, type, and depth of the animal; the 
type (impact or vibratory), depth, intensity, and duration of the pile 
driving sound; the depth of the water column; the substrate of the 
habitat; the distance between the pile and the animal; and the sound 
propagation properties of the environment.
    When piles are driven with impact hammers, they deform, sending a 
bulge travelling down the pile that radiates sound into the surrounding 
air, water, and seabed. This sound may be received by biological 
receivers such as marine mammals through the water, as the result of 
reflected paths from the surface, or re-radiated into the water from 
the seabed (See Figure 3 Appendix J1 of the SFWF COP for a schematic 
diagram illustrating sound propagation paths associated with pile 
driving).
    Noise generated by impact pile driving consists of regular, 
impulsive sounds of short duration. These impulsive sounds are 
typically high energy with fast rise times. Exposure to these sounds 
may result in harassment depending on proximity to the sound source and 
a variety of environmental and biological conditions (Dahl et al. 2015; 
Nedwell et al., 2007). Illingworth & Rodkin (2007) measured an 
unattenuated sound pressure within 10 m (33 ft) at a peak of 220 dB re 
1 [mu]Pa for a 2.4 m (96 in) steel pile driven by an impact hammer, and 
Brandt et al. (2011) found that for a pile driven in a Danish wind farm 
in the North Sea, the peak pressure at 720 m (0.4 nm) from the source 
was 196 dB re 1 [mu]Pa. Studies of underwater sound from pile driving 
finds that most of the acoustic energy is below one to two kHz, with 
broadband sound energy near the source (40 Hz to >40 kHz) and only low-
frequency energy (<~400 Hz) at longer ranges (Bailey et al., 2010; 
Erbe, 2009; Illingworth & Rodkin, 2007). There is typically a decrease 
in sound pressure and an increase in pulse duration the greater the 
distance from the noise source (Bailey et al., 2010). Maximum noise 
levels from pile driving usually occur during the last stage of driving 
each pile where the highest hammer energy levels are used (Betke, 
2008).
    Available information on impacts to marine mammals from pile 
driving associated with offshore wind is limited to information on 
harbor porpoises and seals, as the vast majority of this research has 
occurred at European offshore wind projects where large whales are 
uncommon. Harbor porpoises, one of the most behaviorally sensitive 
cetaceans, have received particular attention in European waters due to 
their protection under the European Union Habitats Directive (EU 1992, 
Annex IV) and the threats they face as a result of fisheries bycatch. 
Brandt et al. (2016) summarized the effects of the construction of 
eight offshore wind projects within the German North Sea between 2009 
and 2013 on harbor porpoises, combining PAM data from 2010-2013 and 
aerial surveys from 2009-2013 with data on noise levels associated with 
pile driving. Baseline analyses were conducted initially to identify 
the seasonal distribution of porpoises in different geographic 
subareas. Results of the analysis revealed significant declines in 
porpoise detections during pile driving when compared to 25-48 hours 
before pile driving began, with the magnitude of decline during pile 
driving clearly decreasing with increasing distances to the 
construction site. During the majority of projects, significant 
declines in detections (by at least 20 percent) were found within at 
least 5-10 km of the pile driving site, with declines at up to 20-30 km 
of the pile driving site documented in some cases. However, there were 
no indications for a population decline of harbor porpoises over the 
five year study period based on analyses of daily PAM data and aerial 
survey data at a larger scale (Brandt et al., 2016). Despite extensive 
construction activities over the study period and an increase in these 
activities over time, there was no long-term negative trend in acoustic 
porpoise detections or densities within any of the subareas studied. In 
some areas, PAM data even detected a positive trend from 2010 to 2013. 
Even though clear negative short-term effects (1-2 days in duration) of 
offshore wind farm construction were found (based on acoustic porpoise 
detections), the authors found no indication that harbor porpoises 
within the German Bight were negatively affected by wind farm 
construction at the population level (Brandt et al., 2016).
    Monitoring of harbor porpoises before and after construction at the 
Egmond aan Zee offshore wind project in the Dutch North Sea showed that 
more porpoises were found in the wind project area compared to two 
reference areas post-construction, leading the authors to conclude that 
this effect was linked to the presence of the wind project, likely due 
to increased food availability as well as the exclusion of fisheries 
and reduced vessel traffic in the wind project (Lindeboom et al., 
2011). The available literature indicates harbor porpoise avoidance of 
pile driving at offshore wind projects has occurred during the 
construction phase. Where long term monitoring has been conducted, 
harbor porpoises have re-populated the wind farm areas after 
construction ceased, with the time it takes to re-populate the area 
varying somewhat, suggesting that while there are short-term impacts to 
porpoises during construction, population-level or long-term impacts 
are unlikely.
    Harbor seals are also a particularly behaviorally sensitive 
species. A harbor seal telemetry study off the East coast of England 
found that seal abundance was significantly reduced up to 25 km from 
WTG pile driving during construction, but found no significant 
displacement resulted from construction overall as the seals' 
distribution was consistent with the non-piling scenario within 2 hours 
of cessation of pile driving (Russell et al., 2016). Based on 2 years 
of monitoring at the Egmond aan Zee offshore wind project in the Dutch 
North Sea, satellite telemetry, while inconclusive, seemed to show that 
harbor seals avoided an area up to 40 km from the construction site 
during pile driving, though the seals were documented inside the wind 
farm after construction ended, indicating any

[[Page 8508]]

avoidance was temporary (Lindeboom et al., 2011).
    Overall, the available literature suggests harbor seals and harbor 
porpoises have shown avoidance of pile driving at offshore wind 
projects during the construction phase in some instances, with the 
duration of avoidance varying greatly, and with re-population of the 
area generally occurring post-construction. The literature suggests 
that marine mammal responses to pile driving in the offshore 
environment are not predictable and may be context-dependent. It should 
also be noted that the only studies available on marine mammal 
responses to offshore wind-related pile driving have focused on species 
which are known to be more behaviorally sensitive to auditory stimuli 
than the other species that occur in the project area. Therefore, the 
documented behavioral responses of harbor porpoises and harbor seals to 
pile driving in Europe should be considered as a worst case scenario in 
terms of the potential responses among all marine mammals to offshore 
pile driving, and these responses cannot reliably predict the responses 
that will occur in other marine mammal species. Harwood et al. (2014) 
discuss a theoretical framework to predict the population level 
consequences of disturbance from offshore renewable energy development 
in the UK on bottlenose dolphins and minke whales (among other 
species), providing illustrative examples of the extent to which each 
species might be exposed to behavioral disturbance or experience PTS on 
a given construction day, as well as probabilities of different levels 
of population decline at the end of the modeled construction period. 
For bottlenose dolphins, most of the simulated populations had declined 
in abundance by less than 5 percent by the time construction of the 
offshore wind project ended; of the simulated minke whale populations, 
the mean decline in abundance was approximately 3 percent. The results, 
which relied heavily on assumptions and expert opinion, highlight the 
need for empirical data to support more robust predictive capabilities 
for assessment of population level impacts of offshore wind development 
on affected species (Harwood et al., 2014).
    Noise generated from vibratory pile driving is mostly concentrated 
at lower frequencies. Rise time is slower, and sound energy is 
distributed over a great amount of time, reducing the probability and 
severity of injury (Nedwell and Edwards, 2002; Carlson et al. 2005). 
Vibratory hammers produce peak SPLs that may be 180 dB or greater, but 
are generally 10 to 20 dB lower than SPLs generated during impact pile 
driving of the same-sized pile (Oestman et al., 2009). Measurements 
from vibratory pile driving of sheet piles during construction 
activities for bridges and piers indicate that root mean square sound 
pressure level SPLrms produced by this activity can range 
from 130 to 170 dB referenced to 1 micropascal squared seconds (dB re 1 
[mu]Pa\2\ s; re 1 [mu]Pa) depending on the measured distance from the 
source and physical properties of the location (Buehler et al., 2015; 
Illingworth and Rodkin, Inc., 2017).
    Masking, which occurs when the receipt of a sound is interfered 
with by a coincident sound at similar frequencies and similar or higher 
levels, may occur during the short periods of vibratory pile driving; 
however, this is unlikely to become biologically significant. It is 
possible that vibratory pile driving resulting from construction and 
removal of the temporary cofferdam may mask acoustic signals important 
to low frequency marine mammals, but the short-term duration 
(approximately 36 hours over 3 non-consecutive days, 18 hours each for 
installation and removal) would result in limited impacts from masking. 
In this case, vibratory pile driving durations are relatively short and 
no significant seal rookeries or haulouts, or cetacean foraging 
habitats are located near the inshore proposed cofferdam locations.
    While thresholds for auditory impairment consider exposure time, 
the metrics used for the behavioral harassment threshold do not 
consider the duration of the animal's exposure to a sound level. 
Therefore, the traditional assessment for behavioral exposures is 
dependent solely on the presence or absence of a species within the 
area ensonified above the threshold. Also, animals are less likely to 
respond to sounds from more distance sources, even when equivalent 
sound levels elicit responses at closer ranges; both proximity and 
received levels are important factors in aversion responses (Dunlop et 
al., 2017).
    HRG surveys may temporarily impact marine mammals in the area due 
to elevated in-water sound levels. Animals exposed to active acoustic 
sources during the HRG survey are unlikely to incur TTS hearing 
impairment due to the characteristics of the sound sources, which 
include relatively narrow beamwidths (e.g., shallow sub-bottom 
profilers) 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., 2012), individuals would have to make a very close 
approach and also remain very close to vessels operating these sources 
in order to receive the multiple exposures at relatively high levels 
that 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., 2009; 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 planned for use (Table 2) makes it 
unlikely that an animal would be exposed more than briefly during the 
passage of the vessel.
    The onset of behavioral disturbance from anthropogenic sound 
depends on both external factors (characteristics of sound sources and 
their paths) and the specific characteristics of the receiving animals 
(hearing, motivation, experience, demography) and is difficult to 
predict (Southall et al., 2007, Ellison et al., 2012). It is possible 
that pile driving could result in temporary, short-term changes in an 
animal's typical behavioral patterns and/or temporary avoidance of the 
affected area. These behavioral changes may include (Richardson et al., 
1995): Changing durations of surfacing and dives, number of blows per 
surfacing, or moving direction and/or speed; reduced/increased vocal 
activities; changing/cessation of certain behavioral activities (such 
as socializing or feeding); visible startle response or aggressive 
behavior (such as tail/fluke slapping or jaw clapping); avoidance of 
areas where sound sources are located; and/or flight responses. The 
biological significance of many of these behavioral disturbances is 
difficult to predict, especially if the detected disturbances appear 
minor. However, the consequences of behavioral modification could be 
expected to be

[[Page 8509]]

biologically significant if the change affects growth, survival, or 
reproduction. Significant behavioral modifications that could lead to 
effects on growth, survival, or reproduction, such as drastic changes 
in diving/surfacing patterns or significant habitat abandonment are 
considered extremely unlikely in the case of the proposed project, as 
it is expected that mitigation measures, including clearance zones and 
soft start (described in detail below, see Proposed Mitigation) will 
minimize the potential for marine mammals to be exposed to sound levels 
that would result in more extreme behavioral responses. In addition, 
marine mammals in the project area are expected to avoid any area that 
would be ensonified at sound levels high enough for the potential to 
result in more severe acute behavioral responses, as the offshore 
environment would allow marine mammals the ability to freely move to 
other areas without restriction.
    In the case of impact pile driving, sound sources would be active 
for relatively short durations (2 to 3 hours per pile), and only one 
pile would be driven per day. The acoustic frequencies produced during 
pile driving activity are lower than those used by most species for 
communication or foraging expected to be present in the project area. 
Given the short duration and the frequency spectra produced by pile 
driving, NMFS expects minimal masking impacts from these activities. 
Further, any masking events that might qualify as Level B harassment 
under the MMPA would be expected to occur concurrently within the zones 
of behavioral harassment already estimated for pile driving, and have, 
therefore, already been taken into account in the exposure analysis. 
The zones of behavioral harassment estimated for vibratory pile driving 
are large (see Estimated Take), but the short duration of this activity 
coupled with the ephemeral use by LF cetaceans (the group most 
susceptible to potential masking from these activities) of the 
nearshore habitat will limit masking impacts. Finally, masking effects 
from HRG survey activities are not anticipated due to the 
characteristics of the acoustic sources (intermittent and higher 
frequency signals), the small isopleths generated by those signals, and 
the influence of the proposed mitigation.

Anticipated Effects on Marine Mammal Habitat

    The proposed activities would result in the placement of 16 
permanent structures (i.e., the monopiles and associated scour 
protection supporting the WTGs and OSS) and a temporary cofferdam in 
the marine environment. HRG surveys would not impact marine mammal 
habitat beyond the noise transmission discussed above, and are, 
therefore, not discussed further in this section. Based on the best 
available information, the long-term presence of the WTGs and OSS is 
not expected to have negative impacts on habitats used by marine 
mammals, and may ultimately have beneficial impacts on those habitats 
as a result of increased presence of prey species in the project area 
due to the WTGs and OSS acting as artificial reefs (Russell et al., 
2014). Although studies assessing the impacts of offshore wind 
development on marine mammals are limited, the repopulation of wind 
energy areas by harbor porpoises (Brandt et al., 2016; Lindeboom et 
al., 2011) and harbor seals (Lindeboom et al., 2011; Russell et al., 
2016) following the installation of wind turbines are promising. SFWF 
would be located within the migratory corridor BIA for North Atlantic 
right whales; however, the 13,000 acre (62.5 km\2\) lease area occupies 
a fraction of the available habitat for North Atlantic right whales 
migrating through the region. Additionally, SFWF would operate a 
relatively small number of WTGs (15) compared to the number of 
foundations in offshore wind farms assessed in e.g., Brandt et al. 
(2016) (range: 30-81; mean: 62), making the footprint comparatively 
small once installation is complete. There are no known foraging 
hotspots, or other ocean bottom structures of significant biological 
importance to marine mammals present in the project area. The proposed 
activities may have potential short-term impacts to food sources such 
as forage fish and could also affect acoustic habitat (see Auditory 
Masking discussion above), but meaningful impacts are unlikely. 
Therefore, the main impact issue associated with the proposed activity 
would be temporarily elevated sound levels and the associated direct 
effects on marine mammals, as discussed previously. The most likely 
impact to marine mammal habitat occurs from impact and vibratory pile 
driving effects on marine mammal prey (e.g., fish). Impacts to the 
immediate substrate during installation of piles are anticipated, but 
these would be limited to minor, temporary suspension of sediments, 
which could impact water quality and visibility for a short amount of 
time, but which would not be expected to have any effects on individual 
marine mammals. Impacts to substrate 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. Additional studies 
have documented effects of pile driving on fish, although several are 
based on studies in support of large, multiyear bridge construction 
projects (e.g., Scholik and Yan, 2001, 2002; Popper and Hastings, 
2009). 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.

[[Page 8510]]

    SPLs of sufficient strength have been known to cause injury to fish 
and fish mortality. However, in most fish species, hair cells in the 
ear continuously regenerate and loss of auditory function likely is 
restored when damaged cells are replaced with new cells. Halvorsen et 
al. (2012a) showed that a TTS of 4-6 dB was recoverable within 24 hours 
for one species. Impacts would be most severe when the individual fish 
is close to the source and when the duration of exposure is long. 
Injury caused by barotrauma can range from slight to severe and can 
cause death, and is most likely for fish with swim bladders. Barotrauma 
injuries have been documented during controlled exposure to impact pile 
driving (Halvorsen et al., 2012b; Casper et al., 2013). As described in 
the Proposed Mitigation section below, South Fork Wind would utilize a 
sound attenuation device which would reduce potential for injury to 
marine mammal prey.
    The most likely impact to fish from impact and vibratory pile 
driving activities at the project areas would be temporary behavioral 
avoidance of the area. The duration of fish avoidance of an area after 
pile driving stops 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 individual pile 
driving events and the relatively small areas being affected.
    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, NMFS concludes that impacts of South Fork Wind's activities are 
not likely to have more than short-term adverse effects on any prey 
habitat or populations of prey species. Further, 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.

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 primarily be by Level B harassment, as noise 
from pile driving and HRG surveys has the potential to result in 
disruption of behavioral patterns for individual marine mammals. There 
is also some potential for auditory injury (Level A harassment) to 
result from impact pile driving. The proposed mitigation and monitoring 
measures are expected to minimize the severity of such taking to the 
extent practicable (see Proposed Mitigation).
    As described previously, no mortality is anticipated or proposed to 
be authorized for these activities. The approach by which take is 
estimated is described below.
    Generally speaking, NMFS estimates 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. NMFS notes 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, NMFS 
describes the factors considered here in more detail and present the 
proposed take estimate.

Acoustic Thresholds

    NMFS recommends the use of acoustic thresholds that identify the 
received level of underwater sound above which exposed marine mammals 
would be reasonably expected to be behaviorally harassed (equated to 
Level B harassment) or to incur PTS of some degree (equated to Level A 
harassment).
    Level B Harassment--Though significantly driven by received level, 
the onset of behavioral disturbance from anthropogenic noise exposure 
is also informed to varying degrees by other factors related to the 
source (e.g., frequency, predictability, duty cycle), the environment 
(e.g., bathymetry), and the receiving animals (hearing, motivation, 
experience, demography, behavioral context) and can be difficult to 
predict (Southall et al., 2007, Ellison et al., 2012). Based on what 
the available science indicates and the practical need to use a 
threshold based on a factor that is both predictable and measurable for 
most activities, NMFS uses a generalized acoustic threshold based on 
received level to estimate the onset of behavioral harassment. NMFS 
predicts that marine mammals are likely to be behaviorally harassed in 
a manner we consider Level B harassment when exposed to underwater 
anthropogenic noise above received levels of 160 dB re 1 [mu]Pa (rms) 
for impulsive and/or intermittent sources. South Fork Wind's proposed 
activity includes the use of impulsive and intermittent sources (e.g., 
impact pile driving, HRG acoustic sources), and thus the 160 dB 
threshold applies.
    Level A harassment--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 South Fork Wind's proposed activity that may result in 
take of marine mammals include the use of impulsive and non-impulsive 
sources.
    These thresholds are provided in Table 5. 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.

[[Page 8511]]



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

Acoustic Modeling

    Here, NMFS describes operational and environmental parameters of 
the activity that will feed into identifying the area ensonified above 
the acoustic thresholds, which include source levels and transmission 
loss coefficient.
Impact Pile Driving: Acoustic Range
    As described above, South Fork Wind is proposing to install up to 
15 WTGs and one OSS in the SFWF (i.e., a maximum of 16 foundations). 
Two piling scenarios may be encountered in the construction of the 
project and were therefore considered in the acoustic modeling study 
conducted to estimate the potential number of marine mammal exposures 
above relevant harassment thresholds: (1) Maximum design, including one 
difficult to drive pile, and (2) standard design with no difficult to 
drive pile included.
    In recognition of the need to ensure that the range of potential 
impacts to marine mammals from the various potential scenarios are 
accounted for, piling scenarios were modeled separately in order to 
conservatively assess the impacts of each. The two monopile 
installation scenarios modeled are:
    (1) The ``maximum design'' consisting of fifteen piles requiring 
~4,500 strikes per pile (per 24 hrs), and one difficult to drive pile 
requiring ~8,000 strikes (per 24 hrs).
    (2) The ``standard design'' consisting of sixteen piles requiring 
~4,500 strike per pile (per 24 hrs).
    Representative hammering schedules of increasing hammer energy with 
increasing penetration depth were modeled, resulting in, generally, 
higher intensity sound fields as the hammer energy and penetration 
increases (Table 6).

                            Table 6--Hammer Energy Schedule for Monopile Installation
----------------------------------------------------------------------------------------------------------------
                                                                                     Difficult
                                                                  Standard  pile    pile strike        Pile
                  Energy level (kilojoule[kJ])                     strike  count   count  (8,000    penetration
                                                                   (4,500 total)      total)            (m)
----------------------------------------------------------------------------------------------------------------
1,000...........................................................             500             800             0-6
1,500...........................................................           1,000           1,200          6-23.5
2,500...........................................................           1,500           3,000         23.5-41
4,000...........................................................           1,500           3,000           41-45
----------------------------------------------------------------------------------------------------------------

    Monopiles were assumed to be vertical and driven to a penetration 
depth of 45 m. While pile penetrations across the site would vary, this 
value was chosen as a reasonable penetration depth. All acoustic 
modeling was performed assuming that only one pile is driven at a time.
    Additional modeling assumptions for the monopiles were as follows:
     One pile installed per day.
     10.97 m steel cylindrical piling with wall thickness of 10 
cm.
     Impact pile driver: IHC S-4000 (4000 kilojoules (kJ) rated 
energy; 1977 kilonewtons (kN) ram weight).
     Helmet weight: 3234 kN.
    Sound fields produced during impact pile driving were modeled by 
first characterizing the sound signal produced during pile driving 
using the industry-standard GRLWEAP (wave equation analysis of pile 
driving) model and JASCO Applied Sciences' (JASCO) Pile Driving Source 
Model (PDSM). The full JASCO modeling report can be found at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act and we provide a summary of the modelling 
effort below.
    Underwater sound propagation (i.e., transmission loss) as a 
function of range from each source was modeled using JASCO's Marine 
Operations Noise Model (MONM) for multiple propagation radials centered 
at the source to yield 3D transmission loss fields in the surrounding 
area. The MONM computes received per-pulse SEL for directional sources 
at specified depths. MONM uses two separate models to estimate 
transmission loss.
    At frequencies less than 2 kHz, MONM computes acoustic propagation 
via a wide-angle parabolic equation (PE) solution to the acoustic wave 
equation based on a version of the U.S. Naval Research Laboratory's 
Range-dependent Acoustic Model (RAM) modified to

[[Page 8512]]

account for an elastic seabed. MONM-RAM incorporates bathymetry, 
underwater sound speed as a function of depth, and a geoacoustic 
profile based on seafloor composition, and accounts for source 
horizontal directivity. The PE method has been extensively benchmarked 
and is widely employed in the underwater acoustics community, and MONM-
RAM's predictions have been validated against experimental data in 
several underwater acoustic measurement programs conducted by JASCO. At 
frequencies greater than 2 kHz, MONM accounts for increased sound 
attenuation due to volume absorption at higher frequencies with the 
widely used BELLHOP Gaussian beam ray-trace propagation model. This 
component incorporates bathymetry and underwater sound speed as a 
function of depth with a simplified representation of the sea bottom, 
as subbottom layers have a negligible influence on the propagation of 
acoustic waves with frequencies above 1 kHz. MONM-BELLHOP accounts for 
horizontal directivity of the source and vertical variation of the 
source beam pattern. Both propagation models account for full exposure 
from a direct acoustic wave, as well as exposure from acoustic wave 
reflections and refractions (i.e., multi-path arrivals at the 
receiver).
    The sound field radiating from the pile was simulated using a 
vertical array of point sources. Because sound itself is an oscillation 
(vibration) of water particles, acoustic modeling of sound in the water 
column is inherently an evaluation of vibration. For this study, 
synthetic pressure waveforms were computed using the full-wave range-
dependent acoustic model (FWRAM), which is JASCO's acoustic propagation 
model capable of producing time-domain waveforms.
    Models are more efficient at estimating SEL than SPLrms. 
Therefore, conversions may be necessary to derive the corresponding 
SPLrms. Propagation was modeled for a subset of sites using 
the FWRAM, from which broadband SEL to SPL conversion factors were 
calculated. The FWRAM required intensive calculation for each site, 
thus a representative subset of modeling sites were used to develop 
azimuth-, range-, and depth-dependent conversion factors. These 
conversion factors were used to calculate the broadband 
SPLrms from the broadband SEL prediction.
    Two locations within the SFWF were selected to provide 
representative propagation and sound fields for the project area (see 
Figure 1 in SFWF COP, Appendix J1). The two locations were selected to 
span the region from shallow to deeper water and varying distances to 
dominant bathymetric features (i.e., slope and shelf break). Water 
depth and environmental characteristics (e.g., bottom-type) are similar 
throughout the SFWF, and therefore minimal differences were found in 
sound propagation results for the two sites (Denes et al., 2018). The 
model also incorporated two different sound velocity profiles (related 
to in situ measurements of temperature, salinity, and pressure within 
the water column) to account for variations in the acoustic propagation 
conditions between summer and winter. Estimated pile driving schedules 
(Table 6) were used to calculate the SEL sound fields at different 
points in time during pile driving.
    The sound propagation modeling incorporated site-specific 
environmental data that describes the bathymetry, sound speed in the 
water column, and seabed geoacoustics in the construction area. Sound 
level estimates are calculated from three-dimensional sound fields and 
then at each horizontal sampling range, the maximum received level that 
occurs within the water column is used as the received level at that 
range. These maximum-over-depth (Rmax) values are then 
compared to predetermined threshold levels to determine acoustic ranges 
to Level A harassment and Level B harassment zone isopleths. However, 
the ranges to a threshold typically differ among radii from a source, 
and might not be continuous because sound levels may drop below 
threshold at some ranges and then exceed threshold at farther ranges. 
To minimize the influence of these inconsistencies, 5 percent of the 
farthest such footprints were excluded from the model data. The 
resulting range, R95percent, is used because, regardless of 
the shape of the maximum-over-depth footprint, the predicted range 
encompasses at least 95 percent of the horizontal area that would be 
exposed to sound at or above the specified threshold. The difference 
between Rmax and R95percent depends on the source 
directivity and the heterogeneity of the acoustic environment. 
R95percent excludes ends of protruding areas or small 
isolated acoustic foci not representative of the nominal ensonified 
zone (see Figure 12; SFWF COP Appendix J1).
    The modeled source spectrum is provided in Figure 7 of the SFWF COP 
(Appendix J1). The dominant energy for both pile driving scenarios 
(``maximum'' and ``standard'') is below 100 Hz. Please see Appendix J1 
of the SFWF COP for further details on the modeling methodology (Denes 
et al., 2020a).
    South Fork Wind will employ a noise mitigation system during all 
impact pile driving of monopiles. Noise mitigation systems, such as 
bubble curtains, are sometimes used to decrease the sound levels 
radiated from a source. Bubbles create a local impedance change that 
acts as a barrier to sound transmission. The size of the bubbles 
determines their effective frequency band, with larger bubbles needed 
for lower frequencies. There are a variety of bubble curtain systems, 
confined or unconfined bubbles, and some with encapsulated bubbles or 
panels. Attenuation levels also vary by type of system, frequency band, 
and location. Small bubble curtains have been measured to reduce sound 
levels but effective attenuation is highly dependent on depth of water, 
current, and configuration and operation of the curtain (Austin, Denes, 
MacDonnell, & Warner, 2016; Koschinski & L[uuml]demann, 2013). Bubble 
curtains vary in terms of the sizes of the bubbles and those with 
larger bubbles tend to perform a bit better and more reliably, 
particularly when deployed with two separate rings (Bellmann, 2014; 
Koschinski & L[uuml]demann, 2013; Nehls, Rose, Diederichs, Bellmann, & 
Pehlke, 2016).
    Encapsulated bubble systems (e.g., Hydro Sound Dampers (HSDs)), can 
be effective within their targeted frequency ranges, e.g., 100-800 Hz, 
and when used in conjunction with a bubble curtain appear to create the 
greatest attenuation. The literature presents a wide array of observed 
attenuation results for bubble curtains. The variability in attenuation 
levels is the result of variation in design, as well as differences in 
site conditions and difficulty in properly installing and operating in-
water attenuation devices. A California Department of Transportation 
(CalTrans) study tested several systems and found that the best 
attenuation systems resulted in 10-15 dB of attenuation (Buehler et 
al., 2015). Similarly, D[auml]hne et al. (2017) found that single 
bubble curtains that reduced sound levels by 7 to 10 dB reduced the 
overall sound level by ~12 dB when combined as a double bubble curtain 
for 6 m steel monopiles in the North Sea. Bellmann et al. (2020) 
provide a review of the efficacy of using bubble curtains (both single 
and double) as noise abatement systems in the German EEZ of the North 
and Baltic Seas. For 8 m diameter monopiles, single bubble curtains 
achieved an average of 11 dB broadband noise reduction (Bellmann et 
al., 2020). In modeling the sound fields for South Fork Wind's proposed 
activities, hypothetical broadband attenuation levels of 0 dB, 6 dB, 10 
dB,

[[Page 8513]]

12 dB, and 15 dB were modeled to gauge the effects on the ranges to 
thresholds given these levels of attenuation. Although five attenuation 
levels (and associated ranges) are provided, South Fork Wind 
anticipates that the use of a noise mitigation system will produce 
field measurements of the isopleth distances to the Level A harassment 
and Level B harassment thresholds that accord with those modeled 
assuming 10 dB of attenuation (see Estimated Take, Proposed Mitigation, 
and Proposed Monitoring and Reporting sections).
    The updated acoustic thresholds for impulsive sounds (such as 
impact pile driving) contained in the Technical Guidance (NMFS, 2018) 
were presented as dual metric acoustic thresholds using both 
SELcum and peak sound pressure level metrics (Table 5). 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.
    Tables 7 and 8 shows the modeled acoustic ranges to the Level A 
harassment thresholds, with 0, 6, 10, 12 and 15 dB sound attenuation 
incorporated. For the peak level, the greatest distances expected 
within a given hearing group are shown, typically occurring at the 
highest hammer energies (Table 7). The SELcum Level A 
harassment threshold is the only metric that is affected by the number 
of strikes within a 24 hr period; therefore, it is only this acoustic 
threshold that is associated with differences in range estimates 
between the standard scenario and the difficult-to drive pile scenario 
(Table 8). The maximum distances for the other two metrics (peak sound 
pressure level (SPLpk) and SPLrms) are equal for 
both scenarios because these metrics are used to define characteristics 
of a single impulse and do not vary based on the number of strikes 
(Denes et al., 2020a). The radial distances shown in Tables 7 and 8 are 
the mean distances from the piles, averaged between the two modeled 
locations and between summer and winter sound velocity profiles.

  Table 7--Mean Acoustic Range (R95%) to Level A Peak Sound Pressure Level (SPLpk) Acoustic Harassment Thresholds for Marine Mammals Due to Impact Pile
                                                                         Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                  Mean distance (m) to threshold
                                                         Threshold SPLpk -------------------------------------------------------------------------------
              Marine mammal hearing group               (dB re 1 [mu]Pa)       0 dB            6 dB            10 dB           12 dB           15 dB
                                                                            attenuation     attenuation     attenuation     attenuation     attenuation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Low-frequency cetaceans...............................               219              87              22               9               7               2
Mid-frequency cetaceans...............................               230               8               2               1               1               1
High-frequency cetaceans..............................               202           1,545             541             243             183             108
Phocid pinnipeds......................................               218             101              26              12               8               2
--------------------------------------------------------------------------------------------------------------------------------------------------------
dB re 1 [mu]Pa = decibel referenced to 1 micropascal.


    Table 8--Mean Acoustic Range (R95%) to Level A Sound Exposure Level (SELcum) Acoustic Harassment Thresholds for Marine Mammals Due to Impact Pile
                            Driving of a Standard Pile (S; 4,500 Strikes*) and a Difficult to Drive Pile (D; 8,000 Strikes*)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                        Mean distance (m) to threshold
                                          Threshold  ---------------------------------------------------------------------------------------------------
      Marine mammal hearing group         SELcum (dB   0 dB attenuation    6 dB attenuation    10 dB attenuation   12 dB attenuation   15 dB attenuation
                                             re 1    ---------------------------------------------------------------------------------------------------
                                         [mu]Pa\2\s)      S         D         S         D         S         D         S         D         S         D
--------------------------------------------------------------------------------------------------------------------------------------------------------
Low-frequency cetaceans................          183    16,416    21,941     8,888    11,702     6,085     7,846     5,015     6,520     3,676     4,870
Mid-frequency cetaceans................          185       107       183        43        59        27        32        27        26        26        26
High-frequency cetaceans...............          155     9,290    13,374     4,012     6,064     2,174     3,314     2,006     2,315       814     1,388
Phocid pinnipeds.......................          185     3,224     4,523     1,375     2,084       673     1,080       437       769       230       415
--------------------------------------------------------------------------------------------------------------------------------------------------------
dB re 1 [mu]Pa\2\ s = decibel referenced to 1 micropascal squared second;
* Approximation.

    Table 9 shows the acoustic ranges to the Level B harassment 
threshold with no attenuation, 6, 10, 12, and 15 dB sound attenuation 
incorporated. Acoustic propagation was modeled at two representative 
sites in the SFWF as described above. The radial distances shown in 
Table 8 are the mean distance to the Level B harassment threshold from 
the piles, derived by averaging the R95percent to the Level 
B harassment thresholds for summer and winter (see Appendix P2 of the 
SFWF COP for more details). The range estimated assuming 10 dB 
attenuation (4,684 m) was used to determine the extent of the Level B 
harassment zone for impact pile driving.

Table 9--Mean Acoustic Range (R95%) to Level B Harassment Acoustic Threshold (SPLrms) Due to Impact Pile Driving
----------------------------------------------------------------------------------------------------------------
                                                          Mean distance (m) to threshold
    Threshold SPLrms (dB re 1    -------------------------------------------------------------------------------
             [mu]Pa)                   0 dB            6 dB            10 dB           12 dB           15 dB
                                    attenuation     attenuation     attenuation     attenuation     attenuation
----------------------------------------------------------------------------------------------------------------
160.............................          11,382           6,884           4,684           4,164           3,272
----------------------------------------------------------------------------------------------------------------
dB re 1 [mu]Pa = decibel referenced to 1 micropascal.


[[Page 8514]]

Impact Pile Driving: Exposure-Based Ranges
    Modeled acoustic ranges to threshold levels may overestimate the 
actual distances at which animals receive exposures meeting the Level A 
(SELcum) harassment threshold criterion. In addition, 
modeled acoustic ranges to thresholds assume that receivers (i.e., 
animals) are stationary. Therefore, such ranges are not realistic, 
particularly for accumulating metrics like SELcum. Applying 
animal movement and behavior (Denes et al. 2020c) within the propagated 
noise fields provides the exposure range, which results in a more 
realistic indication of the distances at which acoustic thresholds are 
met. For modeled animals that have received enough acoustic energy to 
exceed a given threshold, the exposure range for each animal is defined 
as the closest point of approach (CPA) to the source made by that 
animal while it moved throughout the modeled sound field, accumulating 
received acoustic energy. The resulting exposure range for each species 
is the 95th percentile of the CPA distances for all animals that 
exceeded threshold levels for that species (termed the 95 percent 
exposure range [ER95percent). Notably, the 
ER95percent are species-specific rather than categorized 
only by hearing group which affords more biologically-relevant data 
(e.g., dive durations, swim speeds, etc.) to be considered when 
assessing impact ranges. The ER95percent for 
SELcum are provided in Table 10 and are smaller than the 
acoustic ranges calculated using propagation modeling alone (Table 7 
and 8). Please see the Estimated Take section below and Appendix P1 of 
the SFWF COP for further detail on the acoustic modeling methodology. 
The ER95percent ranges assuming 10 dB attenuation for a 
difficult-to-drive pile were used to determine the Level A harassment 
zones for impact pile driving.

Table 10--Exposure-Based Ranges (ER95%) to Level A Sound Exposure Level (SELcum) Harassment Acoustic Thresholds Due to Impact Pile Driving of a Standard
                                      Pile (S; 4,500 Strikes *) and a Difficult to Drive Pile (D; 8,000 Strikes *)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                   ER95% to SELcum thresholds (m)
                                           -------------------------------------------------------------------------------------------------------------
                  Species                     0 dB attenuation      6 dB attenuation      10 dB attenuation     12 dB attenuation     15 dB attenuation
                                           -------------------------------------------------------------------------------------------------------------
                                                S          D          S          D          S          D          S          D          S          D
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Low-Frequency Cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fin whale.................................      5,386      6,741      2,655      2,982      1,451      1,769        959      1,381        552        621
Minke whale...............................      5,196      6,033      2,845      2,882      1,488      1,571        887        964        524        628
Sei whale.................................      5,287      6,488      2,648      3,144      1,346      1,756      1,023      1,518        396        591
Humpback whale............................      9,333     11,287      5,195      5,947      3,034      3,642      2,450      2,693      1,593      1,813
North Atlantic right whale................      4,931      5,857      2,514      3,295      1,481      1,621        918      1,070        427        725
Blue whale \1\............................      5,386      6,741      2,655      2,982      1,451      1,769        959      1,381        552        621
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Mid-Frequency Cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sperm whale...............................          0          0          0          0          0          0          0          0          0          0
Atlantic spotted dolphin..................          0          0          0          0          0          0          0          0          0          0
Atlantic white-sided dolphin..............         20          6         20          6          0          0          0          0          0          0
Common dolphin............................          0          0          0          0          0          0          0          0          0          0
Risso's dolphin...........................         24         13         24          0          0          0          0          0          0          0
Bottlenose dolphin........................         13         13          0          0          0          0          0          0          0          0
Long-finned pilot whale...................          0          0          0          0          0          0          0          0          0          0
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                High-Frequency Cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor porpoise...........................      2,845      3,934        683        996         79        365         26         39         21         26
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Pinnipeds in Water
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gray seal.................................      1,559      1,986        276        552         46        117          0         21          0         21
Harbor seal...............................      1,421      2,284        362        513         22         85         22          0         21          0
--------------------------------------------------------------------------------------------------------------------------------------------------------
dB re 1 [micro]Pa\2\ s = decibel referenced to 1 micropascal squared second.
* Approximation.
\1\ There were no Level A SELcum exposures as a result of animal movement modeling for the blue whale which resulted in a ``0'' exposure range; however,
  an expected exposure range for mitigation purposes must be applied to each species. Therefore, the fin whale exposure range was used as a proxy for
  the blue whale given similarity of species and activity.

Cofferdam Installation and Removal
    For vibratory pile driving (non-impulsive sounds), sound source 
characteristics were generated by JASCO using GRLWEAP 2010 wave 
equation model (Pile Dynamics, Inc., 2010). Installation and removal of 
the cofferdam were modeled from a single location. The radiated sound 
waves were modeled as discrete point sources over the full length of 
the pile in the water and sediment (9.1 m [30 ft] water depth, 9.1 m 
[30 ft] penetration) with a vertical separation of 0.1 m (0.32 ft). 
Removal of the cofferdam using a vibratory extractor is expected to be 
acoustically comparable to installation activities. No noise mitigation 
system will be used during vibratory piling. Summaries of the maximum 
ranges to Level A harassment thresholds and Level B harassment 
thresholds resulting from propagation modeling of vibratory pile 
driving are provided in Table 11. Peak thresholds were not reached for 
any marine mammal hearing group.
    The large Level B harassment isopleths resulting from vibratory 
piling installation and removal are a reflection of the threshold set 
for behavioral disturbance from a continuous noise (i.e., 120 
dBrms). Level B harassment thresholds are highly contextual 
for species and the isopleth distance does not represent a definitive 
impact zone or a suggested mitigation zone; rather, the information 
serves as the basis for assessing potential impacts within the context 
of the project and potentially exposed species.

[[Page 8515]]



Table 11--Distances to Level A Cumulative Sound Exposure Level (SELcum) Harassment Acoustic Thresholds and Level
  B Root-Mean-Square Sound Pressure Level (SPLrms) Acoustic Threshold Due to 18 Hours of Vibratory Pile Driving
----------------------------------------------------------------------------------------------------------------
                                      Level A threshold
                                       SELcum  (dB re 1   Maximum distance  Level B threshold   Maximum distance
     Marine mammal hearing group       [micro]Pa\2\ s)     (m) to Level A    SPLrms  (dB re 1    (m) to Level B
                                                             threshold          [micro]Pa)         threshold
----------------------------------------------------------------------------------------------------------------
Low-frequency cetaceans.............                199              1,470                120             36,766
Mid-frequency cetaceans.............                198                  0                120             36,766
High-frequency cetaceans............                173                 63                120             36,766
Phocid pinnipeds....................                201                103                120             36,766
----------------------------------------------------------------------------------------------------------------
dB re 1 [micro]Pa = decibel referenced to 1 micropascal; [micro]Pa\2\ s = decibel referenced to 1 micropascal
  squared second.

HRG Surveys
    Isopleth distances to Level A harassment thresholds for all types 
of HRG equipment and all marine mammal functional hearing groups were 
modeled using the NMFS User Spreadsheet and NMFS Technical Guidance 
(2018), which provides a conservative approach to exposure estimation.
    NMFS has developed a user-friendly methodology for determining the 
rms sound pressure level (SPLrms) at the 160-dB isopleth for 
the purposes of estimating the extent of Level B harassment isopleths 
associated with HRG survey equipment (NMFS, 2020). This methodology 
incorporates frequency-dependent absorption and some directionality to 
refine estimated ensonified zones. South Fork Wind used NMFS's 
methodology with additional modifications to incorporate a seawater 
absorption formula and account for energy emitted outside of the 
primary beam of the source. For sources that operate with different 
beam widths, the maximum beam width was used (see Table 2). The lowest 
frequency of the source was used when calculating the absorption 
coefficient (Table 2).
    NMFS considers the data provided by Crocker and Fratantonio (2016) 
to represent the best available information on source levels associated 
with HRG equipment and, therefore, recommends that source levels 
provided by Crocker and Fratantonio (2016) be incorporated in the 
method described above to estimate isopleth distances to the Level A 
harassment and Level B harassment thresholds. In cases when the source 
level for a specific type of HRG equipment is not provided in Crocker 
and Fratantonio (2016), NMFS recommends that either the source levels 
provided by the manufacturer be used, or, in instances where source 
levels provided by the manufacturer are unavailable or unreliable, a 
proxy from Crocker and Fratantonio (2016) be used instead. Table 2 
shows the HRG equipment types that may be used during the proposed 
surveys and the sound levels associated with those HRG equipment types.
    Results of modeling using the methodology described above indicated 
that, of the HRG survey equipment planned for use by South Fork Wind 
that has the potential to result in Level B harassment of marine 
mammals, sound produced by the Applied Acoustics Dura-Spark UHD 
sparkers and GeoMarine Geo-Source sparker would propagate furthest to 
the Level B harassment threshold (141 m; Table 12). For the purposes of 
the exposure analysis, it was conservatively assumed that sparkers 
would be the dominant acoustic source for all survey days. Thus, the 
distances to the isopleths corresponding to the threshold for Level B 
harassment for sparkers (141 m) was used as the basis of the take 
calculation for all marine mammals.

  Table 12--Distance to Weighted Level A Harassment and Level B Harassment Thresholds for Each HRG Sound Source or Comparable Sound Source Category for
                                                              Marine Mammal Hearing Groups
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                 Distance to Level A threshold (m)                          Distance to
                                                         --------------------------------------------------------------------------------   Level B (m)
                                                                                                                                         ---------------
                         Source                             LF  (SELcum     MF  (SELcum     HF  (SELcum                     PW  (SELcum     All species
                                                            threshold)      threshold)      threshold)     HF  (SPL0-pk     threshold)        (160 dB
                                                                                                            threshold)                        SPLrms
                                                                                                                                            threshold)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                      Shallow SBPs
--------------------------------------------------------------------------------------------------------------------------------------------------------
ET 216 CHIRP............................................              <1              <1             2.9              --               0              12
ET 424 CHIRP............................................               0               0               0              --               0               4
ET 512i CHIRP...........................................               0               0              <1              --               0               6
GeoPulse 5430...........................................              <1              <1            36.5              --              <1              29
TB CHIRP III............................................             1.5              <1            16.9              --              <1              54
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Medium SBPs
--------------------------------------------------------------------------------------------------------------------------------------------------------
AA Triple plate S-Boom (700/1,000 J)....................              <1               0               0             4.7              <1              76
AA, Dura-spark UHD (500 J/400 tip)......................              <1               0               0             2.8              <1             141
AA, Dura-spark UHD 400+400..............................              <1               0               0             2.8              <1             141
GeoMarine, Geo-Source dual 400 tip sparker..............              <1               0               0             2.8              <1             141
--------------------------------------------------------------------------------------------------------------------------------------------------------
-- = not applicable; [micro]Pa = micropascal; AA = Applied Acoustics; CHIRP = Compressed High-Intensity Radiated Pulse; dB = decibels; ET = EdgeTech; HF
  = high-frequency; J = joules; LF= low-frequency; MF = mid-frequency; PW = Phocids in water; re= referenced to; SBP = sub-bottom profiler; SELcum =
  cumulative sound exposure level in dB re 1 [micro]Pa\2\ s; SPL0-pk = zero to peak sound pressure level in dB re 1 [micro]Pa; TB = teledyne benthos;
  UHD = ultra-high definition; USBL = ultra-short baseline.


[[Page 8516]]

Marine Mammal Occurrence

    This section provides information about the presence, density, or 
group dynamics of marine mammals that will inform the take 
calculations. The best available information regarding marine mammal 
densities in the project area is provided by habitat-based density 
models produced by the Duke University Marine Geospatial Ecology 
Laboratory (Roberts et al., 2016, 2017, 2018, 2020). Density models 
were originally developed for all cetacean taxa in the U.S. Atlantic 
(Roberts et al., 2016); more information, including the model results 
and supplementary information for each of those models, is available at 
seamap.env.duke.edu/models/Duke-EC-GOM-2015/. In subsequent years, 
certain models have been updated on the basis of additional data as 
well as certain methodological improvements. Although these updated 
models (and a newly developed seal density model) are not currently 
publicly available, our evaluation of the changes leads to a conclusion 
that these represent the best scientific evidence available. Marine 
mammal density estimates in the SFWF (animals/km\2\) were obtained 
using these model results (Roberts et al., 2016, 2017, 2018, 2020). As 
noted, the updated models incorporate additional sighting data, 
including sightings from the NOAA Atlantic Marine Assessment Program 
for Protected Species (AMAPPS) surveys from 2010-2016 which included 
some aerial surveys over the RI/MA & MA WEAs (NEFSC & SEFSC, 2011a, 
2011b, 2012, 2014a, 2014b, 2015, 2016). Roberts et al. (2020) further 
updated model results for North Atlantic right whales by incorporating 
additional sighting data and implementing three major changes: 
Increasing spatial resolution, generating monthly estimates on three 
time periods of survey data, and dividing the study area into five 
discrete regions.
    Densities of marine mammals and their subsequent exposure risk are 
different for the wind farm area (where impact pile driving will 
occur), the near shore export cable area (where vibratory pile driving 
will occur), and the HRG survey area. Therefore, density blocks 
(Roberts et al., 2016; Roberts, 2018) specific to each construction 
area were selected for evaluating the potential takes of the 16 
assessed species. The Denes et al. (2020c) model analysis utilized 
North Atlantic right whale densities from the most recent survey time 
period, 2010-2018, as suggested by Roberts et al. (2020).
Monopile Installation
    Mean monthly densities for all animals were calculated using a 60 
km (37.3 mi) square centered on SFWF and overlaying it on the density 
maps from Roberts et al. (2016, 2017, 2018, 2020). The relatively large 
area selected for density estimation encompasses and extends beyond the 
estimated distances to the isopleth corresponding to the Level B 
harassment (with no attenuation, as well as with 6, 10, 12 and 15 dB 
sound attenuation) for all hearing groups using the unweighted 
threshold of 160 dB re 1 [mu]Pa (rms) (Table 9). Please see Figure 3 in 
the SFWF COP (Appendix P2) for an example of a density map showing 
Roberts et al. (2016, 2017, 2018, 2020) density grid cells overlaid on 
a map of the SFWF.
    The mean density for each month was determined by calculating the 
unweighted mean of all 10 x 10 km (6.2 x 6.2 mi) grid cells partially 
or fully within the buffer zone polygon. Mean values from the density 
maps were converted from units of abundance (animals/100 km\2\ [38.6 
miles\2\]) to units of density (animals/km\2\). Densities were computed 
for the months of May to December to coincide with planned pile driving 
activities (as described above, no pile driving would occur from 
January through April). In cases where monthly densities were 
unavailable, annual mean densities (e.g., pilot whales) and seasonal 
mean densities (e.g., all seals) were used instead. Table 13 shows the 
monthly marine mammal density estimates for each species incorporated 
in the exposure modeling analysis. To obtain conservative exposure 
estimates, South Fork Wind used the maximum of the mean monthly (May to 
December) densities for each species to estimate the number of 
individuals of each species exposed above Level A harassment and Level 
B harassment thresholds. The maximum densities applied are denoted by 
an asterisk.

                   Table 13--Estimated Densities (Animals/km-2) Used for Modeling Marine Mammal Exposures Within South Fork Wind Farm
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                              Monthly density (animals km-2)
                           Common name                           ---------------------------------------------------------------------------------------
                                                                     May        Jun        Jul        Aug        Sep        Oct        Nov        Dec
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fin whale.......................................................    0.00201    0.00219  * 0.00264    0.00251    0.00217    0.00145    0.00102    0.00105
Minke whale.....................................................  * 0.00163    0.00143    0.00047    0.00026    0.00027    0.00049    0.00022    0.00032
Sei whale.......................................................  * 0.00019    0.00013    0.00003    0.00002    0.00003    0.00000    0.00001    0.00001
Humpback whale..................................................    0.00133    0.00148    0.00069    0.00094  * 0.00317    0.00156    0.00042    0.00061
North Atlantic right whale......................................  * 0.00154    0.00011    0.00002    0.00001    0.00001    0.00005    0.00029    0.00151
                                                                 ---------------------------------------------------------------------------------------
Blue whale......................................................                                         * 0.00001
                                                                 ---------------------------------------------------------------------------------------
Sperm whale.....................................................    0.00002    0.00008  * 0.00031    0.00024    0.00010    0.00007    0.00007    0.00001
Atlantic white-sided dolphin....................................  * 0.03900    0.03600    0.02500    0.01300    0.01500    0.02200    0.02100    0.02800
Atlantic spotted dolphin........................................    0.00012    0.00016    0.00034    0.00041    0.00051  * 0.00058    0.00037    0.00007
Common bottlenose dolphin.......................................    0.00496    0.01800    0.03700    0.03800  * 0.04000    0.02000    0.00962    0.00846
                                                                 ---------------------------------------------------------------------------------------
Pilot whales \1\................................................                                         * 0.00596
                                                                 ---------------------------------------------------------------------------------------
Risso's dolphin.................................................    0.00005    0.00005    0.00018  * 0.00026    0.00015    0.00005    0.00009    0.00019
Common dolphin..................................................    0.04400    0.04600    0.04300    0.06200    0.10200    0.12800    0.09800  * 0.20400
Harbor porpoise.................................................  * 0.03800    0.00236    0.00160    0.00172    0.00161    0.00399    0.02400    0.02300
Gray seal.......................................................  * 0.03900    0.02600    0.00874    0.00357    0.00529    0.00955    0.00630    0.03400
Harbor seal.....................................................  * 0.03900    0.02600    0.00874    0.00357    0.00529    0.00955    0.00630    0.03400
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Denotes the highest monthly density estimated.
\1\ Long- and short-finned pilot whales are grouped together to estimate the total density of both species.


[[Page 8517]]

Cofferdam Installation and Removal
    Marine mammal densities in the near shore export cable area were 
estimated from the 10 x 10 km habitat density blocks that contained the 
anticipated location of the cofferdam. Monthly marine mammal densities 
for the potential construction locations of the cofferdam are provided 
in Table 14. The maximum densities (denoted by an asterisk) were 
incorporated in the exposure modeling to obtain the most conservative 
estimates of potential take by Level A harassment or Level B 
harassment.
    The species listed in each respective density table represent 
animals that could be reasonably expected within the propagated Level B 
harassment threshold distances at each location, in the months during 
which the cofferdam may be installed and extracted (e.g., October 
through April). Several of the outer continental shelf and deeper water 
species that appear in the SFWF area are not included in the cofferdam 
species list because the densities were zero for those species.

    Table 14--Estimated Densities (Animals/km-2) Used for Modeling Marine Mammal Exposures Within the Affected Area and Construction Schedule of the
                                                                 Cofferdam Installation
--------------------------------------------------------------------------------------------------------------------------------------------------------
                           Species \1\                               Jan        Feb        Mar        Apr        May        Oct        Nov        Dec
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fin whale.......................................................     0.0001     0.0001     0.0002   * 0.0005     0.0002     0.0002     0.0001     0.0001
Minke whale.....................................................     0.0005   * 0.0008     0.0008     0.0000     0.0000     0.0000     0.0005     0.0005
Sei whale.......................................................     0.0001     0.0001     0.0001     0.0000     0.0000     0.0000     0.0000     0.0001
Humpback whale..................................................   * 0.0002     0.0002     0.0002     0.0000     0.0000     0.0000     0.0000     0.0002
North Atlantic right whale......................................   * 0.0014     0.0014     0.0013     0.0008     0.0003     0.0000     0.0002     0.0008
Atlantic white-sided dolphin....................................     0.0001     0.0000     0.0001     0.0002   * 0.0003     0.0003     0.0003     0.0002
Common dolphin..................................................     0.0003     0.0001     0.0001     0.0003     0.0007     0.0007   * 0.0010     0.0008
Common bottlenose dolphin.......................................     0.0694     0.0296     0.0157     0.0474     0.3625   * 0.4822     0.2614     0.0809
Harbor porpoise.................................................     0.0007     0.0005     0.0005     0.0011     0.0007   * 0.0026     0.0003     0.0006
Gray seal.......................................................   * 0.3136     0.3136     0.3136     0.3136     0.3136     0.3136     0.3136     0.3136
Harbor seal.....................................................   * 0.3136     0.3136     0.3136     0.3136     0.3136     0.3136     0.3136     0.3136
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Denotes density used for take estimates.
\1\ Only species with potential exposures are listed.

HRG Surveys
    Densities for HRG surveys were combined for the wind farm area 
(inter-array cables) and the export cable route using density blocks 
that encompassed those areas. The densities used for HRG surveys are 
provided in Table 15. Average annual, rather than maximum monthly, 
densities were estimated to account for spatial variability in the 
distribution of marine mammals throughout the SFWF and SFEC and 
temporal variability in distribution over the 12-month timeframe during 
which HRG surveys would occur.

                    Table 15--Estimated Densities (Animals/km-2) of Marine Mammals Within the High Resolution Geophysical Survey Area
                                                       [Export cable route and inter-array cables]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                                 Annual
             Species                 Jan      Feb      Mar      Apr      May      Jun      July     Aug      Sept     Oct      Nov      Dec    average *
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fin whale........................   0.0020   0.0015   0.0016   0.0027   0.0022   0.0022   0.0025   0.0024   0.0018   0.0018   0.0016   0.0022     0.0020
Minke whale......................   0.0006   0.0007   0.0006   0.0004   0.0005   0.0006   0.0006   0.0004   0.0002   0.0001   0.0006   0.0006     0.0005
Sei whale........................   0.0001   0.0001   0.0001   0.0002   0.0004   0.0002   0.0001   0.0000   0.0000   0.0000   0.0000   0.0001     0.0001
Humpback whale...................   0.0008   0.0007   0.0008   0.0006   0.0009   0.0013   0.0008   0.0010   0.0013   0.0013   0.0013   0.0007     0.0010
North Atlantic right whale.......   0.0038   0.0053   0.0060   0.0054   0.0016   0.0001   0.0000   0.0000   0.0000   0.0000   0.0003   0.0017     0.0020
Sperm whale......................   0.0001   0.0001   0.0001   0.0001   0.0001   0.0001   0.0001   0.0001   0.0001   0.0001   0.0001   0.0001     0.0001
Atlantic white-sided dolphin.....   0.0227   0.0103   0.0078   0.0172   0.0326   0.0276   0.0178   0.0126   0.0202   0.0267   0.0298   0.0352     0.0217
Atlantic spotted dolphin.........   0.0001   0.0001   0.0001   0.0001   0.0001   0.0001   0.0001   0.0001   0.0001   0.0001   0.0001   0.0001     0.0001
Common dolphin...................   0.0218   0.0100   0.0085   0.0182   0.0568   0.0645   0.0417   0.0456   0.0468   0.0538   0.0600   0.0506     0.0399
Common bottlenose dolphin........   0.0081   0.0033   0.0014   0.0035   0.0241   0.0324   0.0544   0.0405   0.0393   0.0392   0.0271   0.0108     0.0237
Risso's dolphin..................   0.0000   0.0000   0.0000   0.0000   0.0000   0.0000   0.0000   0.0000   0.0000   0.0000   0.0000   0.0000     0.0000
Long-finned pilot whale..........   0.0033   0.0033   0.0033   0.0033   0.0033   0.0033   0.0033   0.0033   0.0033   0.0033   0.0033   0.0033     0.0033
Harbor porpoise..................   0.0871   0.0584   0.0475   0.0964   0.0547   0.0182   0.0037   0.0014   0.0024   0.0150   0.0046   0.0482     0.0365
Gray seal........................   0.0151   0.0151   0.0151   0.0151   0.0151   0.0030   0.0030   0.0030   0.0151   0.0151   0.0151   0.0151     0.0121
Harbor seal......................   0.0151   0.0151   0.0151   0.0151   0.0151   0.0030   0.0030   0.0030   0.0151   0.0151   0.0151   0.0151     0.0121
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Annual average density used for take estimates.

Take Calculation and Estimation

    Below is a description of how the information provided above is 
brought together to produce a quantitative take estimate. The following 
steps were performed to estimate the potential numbers of marine mammal 
exposures above Level A harassment and Level B harassment thresholds as 
a result of the proposed activities.
Monopile Installation
    JASCO's Animal Simulation Model Including Noise Exposure (JASMINE) 
animal movement model was used to predict the probability of marine 
mammal exposure to impact pile driving sound. Sound exposure models 
like JASMINE use simulated animals (also known as ``animats'') to 
forecast behaviors of animals in new situations and locations based on 
previously documented behaviors of those animals. The predicted 3D 
sound fields (i.e., the output of the acoustic modeling process 
described earlier) are sampled by animats using movement rules derived 
from animal observations. The output of the simulation is the exposure 
history for each animat within the simulation.
    The precise location of animats (and their pathways) are not known 
prior to a project, therefore a repeated random sampling technique 
(Monte Carlo) is used to estimate exposure probability with many 
animats and randomized starting positions. The probability of an

[[Page 8518]]

animat starting out in or transitioning into a given behavioral state 
can be defined in terms of the animat's current behavioral state, 
depth, and the time of day. In addition, each travel parameter and 
behavioral state has a termination function that governs how long the 
parameter value or overall behavioral state persists in the simulation.
    The output of the simulation is the exposure history for each 
animat within the simulation, and the combined history of all animats 
gives a probability density function of exposure during the project. 
Scaling the probability density function by the real-world density of 
animals (Table 13) results in the mean number of animats expected to be 
exposed over the duration of the project. Due to the probabilistic 
nature of the process, fractions of animats may be predicted to exceed 
threshold. If, for example, 0.1 animats are predicted to exceed 
threshold in the model, that is interpreted as a 10% chance that one 
animat will exceed a relevant threshold during the project, or 
equivalently, if the simulation were re-run ten times, one of the ten 
simulations would result in an animat exceeding the threshold. 
Similarly, a mean number prediction of 33.11 animats can be interpreted 
as re-running the simulation where the number of animats exceeding the 
threshold may differ in each simulation but the mean number of animats 
over all of the simulations is 33.11. A portion of an individual marine 
mammal cannot be taken during a project, so it is common practice to 
round mean number animat exposure values to integers using standard 
rounding methods. However, for low-probability events it is more 
precise to provide the actual values.
    Sound fields were input into the JASMINE model and animats were 
programmed based on the best available information to ``behave'' in 
ways that reflect the behaviors of the 16 marine mammal species 
expected to occur in the project area during the proposed activity. The 
various parameters for forecasting realistic marine mammal behaviors 
(e.g., diving, foraging, surface times, etc.) are determined based on 
the available literature (e.g., tagging studies); when literature on 
these behaviors was not available for a particular species, it was 
extrapolated from a similar species for which behaviors would be 
expected to be similar to the species of interest. Please refer to the 
footnotes on Tables 16 and 17, and Appendix P2 of SFWF COP for a more 
detailed description of the species that were used as proxies when data 
on a particular species was not available. The parameters used in 
JASMINE describe animat movement in both the vertical and horizontal 
planes (e.g., direction, travel rate, ascent and descent rates, depth, 
bottom following, reversals, inter-dive surface interval). More 
information regarding modeling parameters can be found in Denes et al. 
(2020c).
    The mean number of animats that may be exposed to noise exceeding 
acoustic thresholds were calculated for two construction schedules; one 
representing the most likely schedule, and one representing a more 
aggressive, or maximum schedule (Denes et al., 2019). The most likely 
schedule assumes that three foundations are installed per week with an 
average of one pile installed every other day. The maximum schedule 
assumes six monopile foundations are installed per week with one pile 
installation per day. Within each of the construction schedules, a 
single difficult-to-drive pile was included in the model assumptions to 
account for the potential for additional strikes (Denes et al., 2019). 
Animats were modeled to move throughout the three-dimensional sound 
fields produced by each construction schedule for the entire 
construction period. For PTS exposures, both SPLpk and SELcum were 
calculated for each species based on the corresponding acoustic 
criteria. Once an animat is taken within a 24-hrs period, the model 
does not allow it to be taken a second time in that same period but 
rather resets the 24-hrs period on a sliding scale across 7 days of 
exposure. An individual animat's exposure levels are summed over that 
24-hrs period to determine its total received energy, and then compared 
to the threshold criteria. Potential behavioral exposures are estimated 
when an animat is within the area ensonified by sound levels exceeding 
the corresponding thresholds. It should be noted that the estimated 
numbers of individuals exceeding any of the thresholds is conservative 
because the 24-hrs evaluation window allows individuals to be counted 
on multiple days or can be interpreted as different individuals each 
24-hrs period when in the real world it may in fact be the same 
individual experiencing repeated exposures (Denes et al., 2019). Also 
note that animal aversion was not incorporated into the JASMINE model 
runs that were the basis for the take estimate for any species. See 
Appendix P2 of the SFWF COP for more details on the JASMINE modeling 
methodology, including the literature sources used for the parameters 
that were input in JASMINE to describe animal movement for each species 
that is expected to occur in the project area.
    In summary, exposures were estimated in the following way:
    (1) The characteristics of the sound output from the proposed pile-
driving activities were modeled using the GRLWEAP (wave equation 
analysis of pile driving) model and JASCO's PDSM;
    (2) Acoustic propagation modeling was performed within the exposure 
model framework using JASCO's MONM and FWRAM that combined the outputs 
of the source model with the spatial and temporal environmental context 
(e.g., location, oceanographic conditions, seabed type) to estimate 
sound fields;
    (3) Animal movement modeling integrated the estimated sound fields 
with species-typical behavioral parameters in the JASMINE model to 
estimate received sound levels for the animals that may occur in the 
operational area; and
    (4) The number of potential exposures above Level A and Level B 
harassment thresholds was calculated for each potential piling scenario 
(standard, maximum).
    All scenarios were modeled with no sound attenuation and 6, 10, 12, 
and 15 dB sound attenuation. The results of marine mammal exposure 
modeling for the potentially more impactful maximum piling scenarios 
are shown in Tables 16 and 17, as these form the basis for the take 
authorization proposed in this document.

[[Page 8519]]



    Table 16--Modeled Potential Level A Harassment Exposures \1\ Due to Impact Pile Driving Using the Maximum Design Scenario With the Inclusion of 1
                                            Difficult Pile and 0, 6, 10, 12, and 15 dB Broadband Attenuation
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                         0 dB  attenuation      6 dB  attenuation      10 dB  attenuation     12 dB  attenuation     15 dB  attenuation
               Species                ------------------------------------------------------------------------------------------------------------------
                                         SELcum      SPLpk      SELcum      SPLpk      SELcum      SPLpk      SELcum      SPLpk      SELcum      SPLpk
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Low-Frequency Cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fin whale............................           7         <1           3         <1           1         <1           1         <1          <1         <1
Minke whale \2\......................           7         <1           3         <1           1         <1           1         <1          <1         <1
Sei whale \3\........................           1         <1          <1         <1          <1         <1          <1         <1          <1         <1
Humpback whale \2\...................          21         <1           9         <1           4         <1           3         <1           3         <1
North Atlantic right whale \2\.......           4         <1           1         <1          <1         <1          <1         <1          <1         <1
Blue whale...........................          <1         <1          <1         <1          <1         <1          <1         <1          <1         <1
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Mid-Frequency Cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sperm whale..........................          <1         <1          <1         <1          <1         <1          <1         <1          <1         <1
Atlantic spotted dolphin \4\.........          <1         <1          <1         <1          <1         <1          <1         <1          <1         <1
Atlantic white sided dolphin \4\.....          <1         <1          <1         <1          <1         <1          <1         <1          <1         <1
Bottlenose dolphin...................          <1         <1          <1         <1          <1         <1          <1         <1          <1         <1
Common dolphin \4\...................          <1         <1          <1         <1          <1         <1          <1         <1          <1         <1
Risso's dolphin \4\..................          <1         <1          <1         <1          <1         <1          <1         <1          <1         <1
Pilot whale \5\......................          <1         <1          <1         <1          <1         <1          <1         <1          <1         <1
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                High-Frequency Cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor porpoise......................          33         23           4          7       \7\ 1          3           1          3          <1          1
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Pinnipeds in Water
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gray seal \6\........................           6         <1           1         <1          <1         <1          <1         <1          <1         <1
Harbor seal..........................           8          1           2         <1          <1         <1          <1         <1          <1         <1
--------------------------------------------------------------------------------------------------------------------------------------------------------
dB = decibel; SELcum = sound exposure level in units of dB referenced to 1 micropascal squared second; SPLpk = peak sound pressure level in units of dB
  referenced to 1 micropascal.
\1\ The maximum density available for any month was used for each species to estimate the maximum potential exposures (i.e., exposure estimates for all
  species are not for the same month).
\2\ Subset of fin whale behaviors used to approximate model parameters.
\3\ Fin whale used as proxy species for exposure modeling.
\4\ Subset of sperm whale and Atlantic spotted dolphin behaviors used to approximate model parameters.
\5\ Subset of sperm whale behaviors used to approximate model parameters.
\6\ Harbor seal used as proxy species for exposure modeling.
\7\ Calculated exposures with 10 dB for harbor porpoises were <1 but >0.5; therefore they were rounded up to the nearest whole number.

    Again, only the estimated Level B harassment exposures for the 
maximum design pile driving schedule are presented here (Table 17).

Table 17--Modeled Potential Level B Harassment Exposures \1\ Due to Impact Pile Driving Using the Maximum Design
                Scenario With 1 Difficult Pile and 0, 6, 10, 12, and 15 dB Broadband Attenuation
----------------------------------------------------------------------------------------------------------------
                                                   Level B exposures by noise attenuation level
                                 -------------------------------------------------------------------------------
             Species                   0 dB            6 dB            10 dB           12 dB           15 dB
                                    attenuation     attenuation     attenuation     attenuation     attenuation
----------------------------------------------------------------------------------------------------------------
Low-Frequency Cetaceans:
    Fin whale...................              21              10               6               5               4
    Minke whale \2\.............              27              15              10               8               6
    Sei whale \3\...............              <1              <1              <1              <1              <1
    Humpback whale \2\..........              26              13               8               7               6
    North Atlantic right whale                16               7               4               3               3
     \2\........................
    Blue whale..................              <1              <1              <1              <1              <1
Mid-Frequency Cetaceans:
    Sperm whale.................              <1              <1              <1              <1              <1
    Atlantic spotted dolphin \4\               6               3               2               1              <1
    Atlantic white sided dolphin             322             152             107              85              48
     \4\........................
    Bottlenose dolphin..........           1,261             459             197             148              73
    Common dolphin \4\..........               2               1              <1              <1              <1
    Risso's dolphin \4\.........             212              85              43              34              14
    Pilot whale \5\.............              <1              <1              <1              <1              <1
High-Frequency Cetaceans:
    Harbor porpoise.............             272             129              78              67              40
Pinnipeds in Water:
    Gray seal \6\...............             307             116              60              52              28
    Harbor seal.................             319             119              54              45              28
----------------------------------------------------------------------------------------------------------------
dB = decibel.

[[Page 8520]]

 
\1\ The maximum density available for any month was used for each species to estimate the maximum potential
  exposures (i.e., exposure estimates for all species are not for the same).
\2\ Subset of fin whale behaviors used to approximate model parameters.
\3\ Fin whale used as proxy species for exposure modeling.
\4\ Subset of sperm whale and Atlantic spotted dolphin behaviors used to approximate model parameters.
\5\ Subset of sperm whale behaviors used to approximate model parameters.
\6\ Harbor seal used as proxy species for exposure modeling.

    Although exposures are presented according to a range of 
attenuation levels, proposed take numbers are based on an assumption of 
10 dB attenuation and are shown below in Table 18. South Fork Wind 
considers an attenuation level of 10 dB achievable using a single big 
bubble curtain (BBC), which is the most likely noise mitigation system 
that will be used during construction of SFWF. Recently reported in 
situ measurements during installation of large monopiles (~8 m) for 
more than 150 WTGs in comparable water depths (>25 m) and conditions in 
Europe indicate that attenuation levels of 10 dB are readily achieved 
(Bellmann, 2019; Bellmann et al., 2020) using single BBCs as a noise 
mitigation system. Designed to gather additional data regarding the 
efficacy of BBCs, the Coastal Virginia Offshore Wind (CVOW) pilot 
project systematically measured noise resulting from the impact driven 
installation of two 7.8 m monopiles, one with a noise mitigation system 
(double bubble curtain (dBBC)) and one without (CVOW, unpublished 
data). Although many factors contributed to variability in received 
levels throughout the installation of the piles (e.g., hammer energy, 
technical challenges during operation of the dBBC), reduction in 
broadband SEL using the dBBC (comparing measurements derived from the 
mitigated and the unmitigated monopiles) ranged from approximately 9 to 
15 dB. The effectiveness of the dBBC as a noise mitigation measure was 
found to be frequency dependent, reaching a maximum around 1 kHz; this 
finding is consistent with other studies (e.g., Bellman, 2014; Bellman 
et al., 2020). The noise measurements were incorporated into a dampened 
cylindrical transmission loss model to estimate distances to Level A 
and Level B harassment thresholds. The distances to Level A harassment 
and Level B harassment thresholds estimated for the monopile with the 
dBBC were more than 90 percent and 74 percent smaller than those 
estimated for the unmitigated pile, respectively (CVOW).

 Table 18--Proposed Level A Harassment and Level B Harassment Takes of Marine Mammals Resulting From Impact Pile
Driving of Up to 15, 11-m Monopiles Within Inclusion of a Single Difficult Pile at South Fork Wind Farm Using 10
                                         dB Broadband Noise Attenuation
----------------------------------------------------------------------------------------------------------------
                                                                                        Proposed takes \1\
                          Species/stock                              Abundance   -------------------------------
                                                                     estimate         Level A         Level B
----------------------------------------------------------------------------------------------------------------
Fin whale.......................................................           6,802               1               6
Minke whale.....................................................          21,968               1              10
Sei whale.......................................................           6,292            1(0)               1
Humpback whale..................................................           1,393               4               8
North Atlantic right whale......................................             412               0               4
Blue whale......................................................             402               0            1(0)
Sperm whale.....................................................           4,349               0            3(0)
Long-finned pilot whale.........................................          39,921               0               2
Atlantic spotted dolphin........................................          39,921               0               2
Atlantic white-sided dolphin....................................          93,233               0             107
Common dolphin..................................................         172,974               0             197
Risso's dolphin.................................................          35,493               0           30(1)
Common bottlenose dolphin.......................................          62,851               0              43
Harbor porpoise.................................................          95,543               0              78
Gray seal.......................................................         505,000               0              60
Harbor seal.....................................................          75,834               0              54
----------------------------------------------------------------------------------------------------------------
\1\ Parentheses denote animal exposure model estimates. For species with no modeled exposures for Level A
  harassment or Level B harassment, proposed takes for impact pile driving are based on mean group sizes (e.g.,
  sei whale, blue whale, long-finned pilot whale: Kenney and Vigness-Raposa, 2010; sperm whale, Risso's dolphin:
  Barkaszi and Kelly, 2018).

    South Fork Wind conservatively based their exposure modeling on the 
maximum piling scenario, including one difficult-to-drive monopile (out 
of 16) and a compressed buildout schedule (16 piles installed over 20 
days).
    In addition, the acoustic modeling scenario represents only that 
which produced the largest harassment zones and does not reflect all 
the mitigation measures that will be employed during piling operations 
that will serve to reduce the Zone of Influence (ZOI) or increase 
mitigation actions, which may reduce take (see the Proposed Mitigation 
section for details on the measures proposed for implementation).
    Variability in monthly species densities is not considered in South 
Fork Wind's take estimates for monopile driving, which are based on the 
highest mean density value for any month for each species. Given that 
less than 30 days of pile driving will occur, it is unlikely that 
maximum monthly densities would be encountered for all species.
    Finally, start delays and shutdowns of pile hammering are not 
considered in the exposure modeling parameters for monopile driving. 
However, South Fork Wind will delay pile driving if a North Atlantic 
right whale is observed within the Level B harassment zone prior to 
initiating pile driving to avoid take and if a marine mammal is 
observed entering or within the respective exclusion zones after pile 
driving has commenced, an immediate shutdown of pile driving will be 
implemented unless South Fork Wind and/or its contractor determines 
shutdown is not practicable due to an imminent risk of injury or loss 
of life to an individual; or risk of damage to a vessel that creates 
risk of

[[Page 8521]]

injury or loss of life for individuals. There are two scenarios, 
approaching pile refusal and pile instability, where this imminent risk 
could be a factor. These scenarios are considered unlikely and it is 
expected that shutdowns will predominately be practicable during 
operations. See the Proposed Mitigation section for shutdown procedural 
details.
    Although the exposure modeling indicated that Level A harassment 
takes are only expected for a three species of baleen whales (fin 
whale, minke whale, and humpback whale), South Fork Wind requested 
authorization of take by Level A harassment of one sei whale based on 
the occurrence of sei whales in the project area documented during 
prior and ongoing HRG surveys of the SFWF.
    South Fork Wind requested authorization of take equal to the mean 
group size for Level B harassment, based on the best available data 
(seals, Herr et al., 2009; blue whale, long-finned pilot whale, Kenney 
and Vigness-Raposa, 2010; sperm whale, and Risso's dolphin, Barkaszi 
and Kelly, 2018). NMFS agrees that this approach is appropriate in 
cases where instantaneous exposure is expected to result in harassment, 
e.g., Level B harassment and calculated take estimates are either zero 
or less than the group size.
Cofferdam Installation and Removal
    Animal movement and exposure modeling was not used to determine 
potential exposures from vibratory pile driving. Rather, the modeled 
acoustic range distances to isopleths corresponding to the Level A 
harassment and Level B harassment threshold values were used to 
calculate the area around the cofferdam predicted to be ensonified 
daily to levels that exceed the thresholds, or the ZOI. ZOI is 
calculated as the following:

ZOI = [pi]r\2\,

where r is the linear acoustic range distance from the source to the 
isopleth for Level A harassment or Level B harassment thresholds. 
This area was adjusted to account for the portion of the ZOI 
truncated by the coastline of Long Island, NY.

    The daily area was then multiplied by the maximum monthly density 
of a given marine mammal species. Roberts et al. (2018) produced 
density models for all seals but 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 the 
mean annual density of seals could refer to either of the respective 
species and was, therefore, divided equally between the two species.
    Finally, the resulting value was multiplied by the number of 
proposed activity days which is, for cofferdam installation and 
removal, conservatively estimated as two days. Modeling of the Level A 
harassment exposures resulting from two 18-hrs periods of vibratory 
pile driving and removal resulted in less than one exposure for all 
species for each month between October 1 and May 31. Modeled potential 
Level B harassment exposures resulting from installation and extraction 
of the cofferdam are shown in Table 19.

                    Table 19--Modeled Level B Harassment Exposures Resulting From Vibratory Pile Driving and Removal of the Cofferdam
--------------------------------------------------------------------------------------------------------------------------------------------------------
                             Species                                 Jan        Feb        Mar        Apr        May        Oct        Nov        Dec
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fin whale.......................................................          0          0          1          2          1          1          0          0
Minke whale.....................................................          2          3          3          0          0          0          2          2
Sei whale.......................................................          0          0          0          0          0          0          0          0
Humpback whale..................................................          1          1          1          0          0          0          0          1
North Atlantic right whale......................................          6          6          5          3          1          0          1          3
Atlantic white-sided dolphin....................................          0          0          0          1          1          1          1          1
Common dolphin..................................................          1          0          0          1          3          3          4          3
Common bottlenose dolphin.......................................        289        123         65        197      1,509      2,007      1,088        337
Harbor porpoise.................................................          3          2          2          5          3         11          1          2
Gray seal.......................................................      1,305      1,305      1,305      1,305      1,305      1,305      1,305      1,305
Harbor seal.....................................................      1,305      1,305      1,305      1,305      1,305      1,305      1,305      1,305
--------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum 18-hour periods of vibratory pile driving or removal will be separated by at least 24 hours of no vibratory sound source operating at the
  cofferdam.

    Modeled vibratory pile driving activities for the SFEC (SFWF COP 
Appendix J1 [Denes et al., 2018]) resulted in mean acoustic ranges to 
the PTS threshold for low frequency cetaceans, ranging from 742 m for 6 
hrs of piling to 1,470 m for 18 hrs of piling (Denes et al., 2018). 
Maximum acoustic ranges to PTS thresholds for other marine mammal 
hearing groups are all under 103 m. Level A harassment exposures are 
not expected due to low population densities of LFC species in the 
project area, animal movement and required accumulation periods (Denes 
et al., 2019), the short duration of vibratory pile driving, and 
proposed mitigation measures (see Proposed Mitigation section).
    Vibratory pile driving during cofferdam installation and removal 
for the SFEC does have the potential to elicit behavioral responses in 
marine mammals. However, predicting Level B harassment exposure 
estimates resulting from vibratory pile driving is complicated by the 
nearshore location, short duration of cofferdam installation and 
removal, and static species density data that are not indicative of 
animals transiting the nearshore environment. Marine mammal densities 
at the near shore export cable area were estimated from the 10 x 10 km 
habitat density block from Roberts et al. (2016) and Roberts et al. 
(2018) that contained the anticipated location of the temporary 
cofferdam. However, the density estimates are not provided for the area 
adjacent to the shoreline, although some density blocks do intersect 
the shore. Due to this structure, densities are artificially weighted 
to the nearest 100 km\2\ offshore and do not adequately represent the 
low numbers expected for some groups like large whales. In addition, 
the species densities represented in the Roberts et al. (2016) and 
Robert et al. (2018) are provided as monthly estimates and are, 
therefore, not indicative of a single-day distribution of animals 
within the potential ensonified zone. The modeled behavioral harassment 
threshold acoustic ranges extend beyond 36 km from the source (Table 
11); despite this extensive Level B harassment zone, only bottlenose 
dolphin, harbor seal, and gray seal exposure estimates are relatively 
large. However, the low densities of most species nearshore, the 
seasonality of occurrence, and the transitory nature of marine mammals

[[Page 8522]]

within the small time period of vibratory pile driving significantly 
reduces the risk of behavioral harassment exposures. In addition, 
marine mammal species in this region are not expected to remain in 
proximity to the cofferdam location for an extended amount of time. 
Although the modeled Level B harassment exposure estimates for harbor 
and gray seals were large (1,305), seals are only expected to be 
seasonally present in the region, and there are no known rookeries 
documented near the cofferdam location. Seals typically haul-out for 
some portion of their daily activities, often in large groups (Hayes et 
al., 2020); however, the in-water median group size is estimated to be 
1-3 animals depending on the distance to shore (Herr et al., 2009) with 
larger groups typically being associated with direct proximity to a 
haul-out site. There are a few documented haul-out sites around Long 
Island, New York; the nearest site is in Montauk Point, approximately 
20 km northeast of the cofferdam location, where seals are primarily 
observed in winter (CRESLI, 2019). Long Island, NY represents the 
northernmost portion of the range for the Western North Atlantic 
Migratory Coast Stock of bottlenose dolphins. Bottlenose dolphin 
occurrence is also seasonal along the coast of Long Island, peaking in 
late summer/early fall (Hayes et al., 2020). Potential exposures of 
bottlenose dolphins varied substantially across the proposed 
construction months, with a minimum number of potential Level B 
harassment exposures in March (65) and a maximum in October (2007). The 
impact of vibratory pile driving on this species (and both seal 
species) will be largely dependent on the timing of the installation 
and extraction of the cofferdam.
    Given the possibility that vibratory pile driving could occur 
anytime between October and May, the maximum modeled exposure for each 
species (across months) was used to conservatively predict take numbers 
and assess impacts resulting from vibratory pile driving (Table 20).

Table 20--Proposed Level B Harassment Take Resulting From Vibratory Pile
                                 Driving
------------------------------------------------------------------------
                                            Population       Proposed
              Species/stock                  estimate      level B takes
------------------------------------------------------------------------
Fin whale...............................           6,802               2
Minke whale.............................          21,968               3
Sei whale...............................           6,292               0
Humpback whale..........................           1,393               1
North Atlantic right whale..............             412               6
Atlantic white sided dolphin............          93,233               1
Common dolphin..........................         172,974               4
Bottlenose dolphin......................          62,851           2,007
Harbor porpoise.........................          95,543              11
Gray seal...............................         505,000           1,305
Harbor seal.............................          75,834           1,305
------------------------------------------------------------------------

HRG Surveys
    Potential exposures of marine mammals to acoustic impacts from HRG 
survey activities were estimated using an approach similar to that 
described for installation and removal of a cofferdam. For HRG surveys, 
however, the ZOI was calculated as follows:

ZOI = 2rd + [pi]r\2\

where r is the linear acoustic range from the source to the largest 
estimated Level A harassment (36.5 m) and Level B harassment (141 m) 
isopleths, and d is the survey trackline distance per day (70 km).

    The daily area was then multiplied by the mean annual density of a 
given marine mammal species. Finally, the resulting value was 
multiplied by the number of proposed survey days (60).
    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 12). Based on the extremely 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. These three 
functional hearing groups encompass all but one of the marine mammal 
species listed in Table 3 that may be impacted by the proposed 
activities. There is one species (harbor porpoise) within the high 
frequency functional hearing group that may be impacted by the proposed 
activities. However, the largest modeled distance to the Level A 
harassment threshold for the high frequency functional hearing group 
was only 36.5 m (Table 12). More importantly, 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 the 
narrow beam width and directional nature of the sources, as well as the 
mitigation measures (including a 100 m exclusion zone for harbor 
porpoises), minimize the potential for exposure to HRG sources that 
would result in Level A harassment. 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, NMFS 
has determined that the potential for take by Level A harassment of 
harbor porpoises is so low as to be discountable. The modeled Level B 
harassment exposures of marine mammals resulting from HRG survey 
activities are shown in Table 21.

[[Page 8523]]



  Table 21--Modeled Level B Harassment Exposures Species Resulting From
        High Resolution Geophysical Surveys of the SFWF and SFEC
------------------------------------------------------------------------
                                                             Estimated
                 Species                    Population        level B
                                             estimate        exposures
------------------------------------------------------------------------
Fin whale...............................           6,802               3
Minke whale.............................          21,968               1
Sei whale...............................           6,292              <1
Humpback whale..........................           1,393               1
North Atlantic right whale..............             412               3
Sperm whale.............................           4,349              <1
Atlantic spotted dolphin................          39,921              <1
Atlantic white-sided dolphin............          93,233              26
Common dolphin..........................         172,974              47
Bottlenose dolphin......................          62,851              28
Risso's dolphin.........................          35,493              <1
Long-finned pilot whale.................          39,215               4
Harbor porpoise.........................          95,543              43
Gray Seal...............................         505,000              14
Harbor seal.............................          75,834              14
------------------------------------------------------------------------

    The proposed number of takes by Level B harassment resulting from 
HRG survey activities are shown in Table 22. Again, 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 and South Fork Wind did not 
request any take by Level A harassment associated with HRG surveys, 
NMFS does not propose to authorize take by Level A harassment of any 
marine mammals.
    The seasonal mean number of minke whales sighted during HRG surveys 
conducted by South Fork Wind in 2017 and 2018 was 19; therefore, South 
Fork increased the number of takes requested for minke whales from 1 to 
19. Preliminary Protected Species Observer (PSO) reports from SFWF 
during 2019 and 2020 HRG surveys show a high number of common dolphin 
detections within the estimated Level B harassment zones. Using a mean 
group size of 25, South Fork Wind multiplied the mean group size by the 
number of Level B harassment exposures modeled (47) to produce the 
number of takes they requested by Level B harassment (1,175). There 
were no exposures estimated for several species; however, as a 
precautionary measure, South Fork Wind requested Level B harassment 
takes for those species based on published values of mean group sizes 
(sei whale, Kenney and Vigness-Raposa, 2010; sperm whale, Barkaszi and 
Kelly, 2018; Atlantic spotted dolphin, Barkaszi and Kelly, 2018; 
Risso's dolphin, Barkaszi and Kelly, 2018). The number of minke whale 
Level B harassment takes requested by South Fork Wind is based on the 
seasonal mean number of minke whales sighted during HRG surveys of SFWF 
in 2017 and 2018.

Table 22--Proposed Amount of Level B Harassment Take Resulting From High
           Resolution Geophysical Surveys of the SFWF and SFEC
------------------------------------------------------------------------
                                                             Proposed
              Species/stock                 Population     level B takes
                                             estimate           \1\
------------------------------------------------------------------------
Fin whale...............................           6,802               3
Minke whale.............................          21,968           19(1)
Sei whale...............................           6,292            1(0)
Humpback whale..........................           1,393               1
North Atlantic right whale..............             412               3
Sperm whale.............................           4,349            3(0)
Long-finned pilot whale.................          39,215               4
Atlantic spotted dolphin................          39,921           13(0)
Atlantic white sided dolphin............          93,233              26
Common dolphin..........................         172,974       1,175(47)
Risso's dolphin.........................          35,493           30(0)
Common bottlenose dolphin...............          62,851              28
Harbor porpoise.........................          95,543              43
Gray seal...............................         505,000              14
Harbor seal.............................          75,834              14
------------------------------------------------------------------------
\1\ The modeled number of takes is shown in parenthesis.

Combined Activity Proposed Takes
    Level A harassment and Level B harassment proposed takes for the 
combined activities of impact pile driving using a noise attenuation 
device, vibratory pile driving, and HRG surveys are provided in Table 
23. NMFS also presents the percentage of each stock taken based on the 
total amount of take. The mitigation and monitoring measures provided 
in the Proposed Mitigation and Proposed Monitoring and Reporting 
sections are activity-specific and are designed to minimize acoustic 
exposures to marine mammal species.
    The take numbers NMFS proposes for authorization (Table 23) are 
considered

[[Page 8524]]

conservative for the following key reasons:
     Proposed take numbers for impact pile driving assume a 
maximum piling schedule (16 monopiles installed in 20 days);
     Proposed take numbers for vibratory pile driving assume 
that a sheet pile temporary cofferdam will installed (versus the 
alternative installation of a gravity cell cofferdam, for which no take 
is anticipated);
     Proposed take numbers for pile driving are conservatively 
based on maximum densities across the proposed construction months;
     Proposed Level A harassment take numbers do not fully 
account for the likelihood that marine mammals will avoid a stimulus 
when possible before the individual accumulates enough acoustic energy 
to potentially cause auditory injury;
     Proposed take numbers do not fully account for the 
effectiveness of proposed mitigation and monitoring measures in 
reducing the number of takes to effect the least practicable adverse 
impact (with the exception of the seasonal restriction on impact pile 
driving, which is accounted for in the proposed take numbers).

  Table 23--Proposed Takes by Level A Harassment and Level B Harassment for All Activities \1\ Conducted During
                                                SFWF Construction
----------------------------------------------------------------------------------------------------------------
                                                    Proposed take authorization
                                                   combined for all construction
                                    Population              activities            Total proposed   * Percentage
          Species/stock              estimate    --------------------------------  takes  (level   of population
                                                     Proposed        Proposed      A +  level B)   or stock  (%)
                                                   level A takes   level B takes
----------------------------------------------------------------------------------------------------------------
Fin whale.......................           6,802               1              11              12            0.18
Minke whale.....................          21,968               1              32              33            0.15
Sei whale.......................           6,292               1               2               3            0.05
Humpback whale..................           1,393               4              10              14            1.01
North Atlantic right whale......             412               0              13              13            3.16
Blue whale......................             402               0               1               1            0.20
Sperm whale.....................           4,349               0               6               6            0.14
Pilot whales (long-finned)......          39,215               0              16              16            0.04
Atlantic spotted dolphin........          39,921               0              15              15            0.04
Atlantic white sided dolphin....          93,233               0             133             133            0.14
Common dolphin..................         172,974               0           1,372           1,372            0.79
Risso's dolphin.................          35,493               0              60              60            0.17
Common Bottlenose dolphin.......          62,851               0           2,078           2,078            3.31
Harbor porpoise.................          95,543               0             132             132            0.14
Gray seal.......................         505,000               0           1,379           1,379            0.27
Harbor seal.....................          75,834               0           1,379           1,379            1.81
----------------------------------------------------------------------------------------------------------------
\1\ Activities include impact pile driving using a noise mitigation system (NMS) from May through October,
  vibratory pile driving (October through May), and HRG surveys (year-round).
* Calculations of percentage of stock taken are based on the best available abundance estimate as shown in Table
  3. The best available abundance estimates are derived from the draft 2020 NMFS Stock Assessment Reports (Hayes
  et al., 2020). NMFS stock abundance estimate for gray seals applies to U.S. population only, actual stock
  abundance is approximately 505,000.

Proposed Mitigation

    In order to issue an IHA under Section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to such 
activity, and other means of effecting the least practicable impact on 
such species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of such species or stock for taking for certain 
subsistence uses (latter not applicable for this action). NMFS 
regulations require applicants for incidental take authorizations to 
include information about the availability and feasibility (economic 
and technological) of equipment, methods, and manner of conducting such 
activity or other means of effecting the least practicable adverse 
impact upon the affected species or stocks and their habitat (50 CFR 
216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, NMFS 
carefully considers two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned), the likelihood of effective implementation (probability 
implemented as planned), and;
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost and impact on 
operations.
    The mitigation strategies described below are consistent with those 
required and successfully implemented under previous incidental take 
authorizations issued in association with in-water construction 
activities. Additional measures have also been incorporated to account 
for the fact that the proposed construction activities would occur 
offshore. Modeling was performed to estimate harassment zones, which 
were used to inform mitigation measures for pile driving activities to 
minimize Level A harassment and Level B harassment to the extent 
practicable.
    In addition to the specific measures described later in this 
section, South Fork Wind would conduct briefings for construction 
supervisors and crews, the marine mammal and acoustic monitoring teams, 
and South Fork Wind staff prior to the start of all pile driving and 
HRG survey activity, and when new personnel join the work, in order to 
explain responsibilities, communication procedures, the marine mammal 
monitoring protocol, and operational procedures.

[[Page 8525]]

Monopile Installation

Seasonal Restriction on Impact Pile Driving
    No impact pile driving activities would occur January 1 through 
April 30. This seasonal restriction would minimize the potential for 
North Atlantic right whales to be exposed to pile driving noise. Based 
on the best available information (Kraus et al., 2016; Roberts et al., 
2020), the highest densities of North Atlantic right whales in the 
project area are expected during the months of January through April. 
This restriction is expected to greatly reduce the potential for North 
Atlantic right whale exposure to pile driving noise associated with the 
proposed project.
Clearance and Exclusion Zones
    South Fork Wind would use PSOs to establish clearance zones around 
the pile driving equipment to ensure these zones are clear of marine 
mammals prior to the start of pile driving. The purpose of 
``clearance'' of a particular zone is to prevent potential instances of 
auditory injury and potential instances of more severe behavioral 
disturbance as a result of exposure to pile driving noise (serious 
injury or death are unlikely outcomes even in the absence of mitigation 
measures) by delaying the activity before it begins if marine mammals 
are detected within certain pre-defined distances of the pile driving 
equipment. The primary goal in this case is to prevent auditory injury 
(Level A harassment), and the proposed clearance zones are larger than 
the modeled distances to the isopleths (assuming an effective 10 dB 
attenuation of pile driving noise) corresponding to Level A harassment 
for all marine mammal species (excluding humpback whales). These zones 
vary depending on species and are shown in Table 24. All distances to 
the perimeter of clearance zones are the radius from the center of the 
pile. The pre-start clearance zones for large whales, harbor porpoises, 
and seals are based upon the maximum distance to the Level A harassment 
isopleth for each group (excluding humpback whales) plus a 20 percent 
buffer, rounded up for PSO clarity. The North Atlantic right whale 
Level A harassment zone is conservatively based on the Level B 
harassment zone, and the distance to the perimeter of the clearance 
zone is rounded up from 4,684 m to 5,000 m. Although the Level A 
harassment zones are small, mid-frequency cetacean (except sperm 
whales) zones were established using a precautionary distance of 100 m 
and will extend to that distance or just beyond the placement of the 
noise mitigation system, whichever is further.
    The exclusion zones for large whales, North Atlantic right whale, 
porpoise, and seals are based upon the maximum Level A harassment zone 
for each group (excluding humpback whales), increased by a 10 percent 
buffer and rounded up for PSO clarity. Similar to clearance zones, mid-
frequency cetacean (except sperm whale) exclusion zones will extend to 
the larger of two distances: 50 m or just outside the noise mitigation 
system.
    The Level A harassment zone is larger for humpback whales than 
other low frequency baleen whales because animal movement modeling used 
to estimate the associated isopleth relies on behavior-based exposures 
with no aversion (based on the best available data that inform the 
animat models); specific movement parameters help drive the larger zone 
size for humpbacks, including a modeled preference for slightly deeper 
water than the depths in the SFWF. This modeled preference resulted in 
fewer exposures, but each exposure was farther from the impact piling 
location, producing the larger Level A harassment zone. While the 
clearance zone (2,200 m) for humpback whales is smaller than the Level 
A harassment zone (3,642 m), visual monitoring would be conducted from 
both the construction vessel and a secondary, smaller vessel (on which 
dedicated PSOs would be deployed) surveying the circumference of the 
construction vessel at a radius approximate to the pre-start clearance 
zone for large whales (2,200 m). NMFS expects that this additional 
visual monitoring would facilitate detection of humpback whales within 
the Level A harassment zone.
    South Fork Wind would establish a clearance zone for North Atlantic 
right whales slightly larger than the Level B harassment zone to 
minimize all take. If a North Atlantic right whale is detected nearing 
the exclusion zone, shutdown would be triggered. NMFS agrees that, 
under typical conditions, South Fork Wind would be capable of 
monitoring this zone using a combination of visual monitoring from both 
the construction vessel and secondary monitoring vessel (described 
above), and real-time PAM, which would occur before, during, and after 
driving using a combination of acoustic detection systems (e.g., moored 
buoys, free-floating arrays). Communication of marine mammal 
detections, either visual or acoustic, among PSOs on both vessels and 
PAM operators would facilitate both clearance of the zone and 
initiation of shutdown, if required.

             Table 24--Proposed Clearance and Exclusion Zones \1\ During South Fork Wind Impact Pile Driving With a Noise Mitigation System
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Level A         Level A         Level B        Pre-start                        Vessel
                         Species                            harassment      harassment      harassment    clearance zone  Exclusion zone    separation
                                                          zone (m) (SEL)   zone (m) (PK)     zone (m)           (m)             (m)        distance (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Low-frequency Cetaceans:
    Fin whale...........................................           1,756            <=10           4,684           2,200           2,000             100
    Minke whale.........................................           1,571            <=10           4,684           2,200           2,000             100
    Sei whale...........................................           1,769            <=10           4,684           2,200           2,000             100
    Humpback whale......................................           3,642            <=10           4,684           2,200           2,000             100
    North Atlantic right whale..........................           1,621            <=10           4,684           5,000           2,000             500
    Blue whale \2\......................................           1,756            <=10           4,684           2,200           2,000             100
Mid-frequency Cetaceans:
    Sperm whale.........................................  ..............            <=10           4,684           2,200           2,000             100
    Atlantic spotted dolphin............................  ..............            <=10           4,684             100              50              50
    Atlantic white-sided dolphin........................  ..............            <=10           4,684             100              50              50
    Common dolphin......................................  ..............            <=10           4,684             100              50              50
    Risso's dolphin.....................................  ..............            <=10           4,684             100              50              50
    Bottlenose dolphin..................................  ..............            <=10           4,684             100              50              50
    Long-finned pilot whale.............................  ..............            <=10           4,684             100              50              50
High-frequency Cetaceans:

[[Page 8526]]

 
    Harbor porpoise.....................................             365             301           4,684             450             450              50
Phocid Pinnipeds in Water:
    Gray seal...........................................             120            <=10           4,684             150             150              50
    Harbor seal.........................................              85            <=10           4,684             150             150              50
--------------------------------------------------------------------------------------------------------------------------------------------------------
dB = decibel; SEL = cumulative sound exposure level PK = peak sound pressure level.
\1\ Zones are based upon the following modeling assumptions: 11-m monopile installation with inclusion of a difficult to install pile that requires
  approximately 8,000 hammer strikes and mitigated with10 dB broadband noise attenuation from a noise mitigation system. Only 1 pile out of the 16 total
  monopiles is expected to be a difficult pile.
\2\ No Level A exposures were calculated for blue whales resulting in no expected Level A exposure range; therefore, the exposure range for fin whales
  was used as a proxy due to similarities in species.

    If a marine mammal is observed approaching or entering the relevant 
clearance zones prior to the start of pile driving, pile driving 
activity will be delayed until either the marine mammal has voluntarily 
left the respective clearance zone and been visually confirmed beyond 
that clearance zone, or, 30 minutes have elapsed without re-detection 
of the animal in the case of mysticetes, sperm whales, Risso's dolphins 
and pilot whales, or 15 minutes have elapsed without re-detection of 
the animal in the case of all other marine mammals.
    Prior to the start of pile driving activity, the clearance zones 
will be monitored for 60 minutes using a combined effort of passive 
acoustic monitoring and visual observation to ensure that they are 
clear of the relevant species of marine mammals. Pile driving would 
only commence once PSOs have declared the respective clearance zones 
clear of marine mammals. Marine mammals observed within a clearance 
zone will be allowed to remain in the clearance zone (i.e., must leave 
of their own volition), and their behavior will be monitored and 
documented. The clearance zones may only be declared clear, and pile 
driving started, when the entire clearance zones are visible (i.e., 
when not obscured by dark, rain, fog, etc.) for a full 60 minutes 
immediately prior to commencing pile driving. For North Atlantic right 
whales, the clearance zone may be declared clear if no visual or 
acoustic detections have occurred during the 60 minute monitoring 
period. 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 
exclusion zone, shutdown would be required.
Soft Start of Impact Pile Driving
    The use of a soft start procedure is believed to provide additional 
protection to marine mammals by warning marine mammals or providing 
them with a chance to leave the area prior to the hammer operating at 
full capacity, and typically involves a requirement to initiate sound 
from the hammer at reduced energy followed by a waiting period. South 
Fork Wind will utilize soft start techniques for impact pile driving 
including by performing 4-6 strikes per minute at 10 to 20 percent of 
the maximum hammer energy, for a minimum of 20 minutes. NMFS notes that 
it is difficult to specify the reduction in energy for any given hammer 
because of variation across drivers and, for impact hammers, the actual 
number of strikes at reduced energy will vary because operating the 
hammer at less than full power results in ``bouncing'' of the hammer as 
it strikes the pile, resulting in multiple ``strikes''; however, as 
mentioned previously, South Fork Wind has proposed that they will 
target less than 20 percent of total hammer energy for the initial 
hammer strikes during soft start. Soft start would be required at the 
beginning of each day's impact pile driving work and at any time 
following a cessation of impact pile driving of thirty minutes or 
longer.
Shutdown of Impact Pile Driving Equipment
    The purpose of a shutdown is to prevent some undesirable outcome, 
such as auditory injury or severe behavioral disturbance of sensitive 
species, by halting the activity. If a marine mammal is observed 
entering or within the respective exclusion zone (Table 24) after pile 
driving has begun, the PSO will request a temporary cessation of pile 
driving.
    In situations when shutdown is called for but South Fork Wind 
determines shutdown is not practicable due to imminent risk of injury 
or loss of life to an individual, or risk of damage to a vessel that 
created risk of injury or loss of life for individuals, reduced hammer 
energy would be implemented when practicable. After shutdown, pile 
driving may be initiated once all clearance zones are clear of marine 
mammals for the minimum species-specific time periods, or, if required 
to maintain installation feasibility. Installation feasibility refers 
to ensuring that the pile installation results in a usable foundation 
for the WTG (e.g., installed to the target penetration depth without 
refusal and with a horizontal foundation/tower interface flange).
Visibility Requirements
    Pile driving would not be initiated at night, or, when the full 
extent of all relevant clearance zones cannot be confirmed to be clear 
of marine mammals, as determined by the lead PSO on duty. The clearance 
zones may only be declared clear, and pile driving started, when the 
full extent of all clearance zones are visible (i.e., when not obscured 
by dark, rain, fog, etc.) for a full 60 minutes prior to pile driving. 
Pile driving may continue after dark only when the driving of the same 
pile began no less than 90 minutes prior to civil sunset, when 
clearance zones were fully visible, and must proceed for human safety 
or installation feasibility reasons. PSOs would utilize night vision 
devices (NVDs) (Infrared (IR) and/or thermal cameras) to monitor 
clearance zones if pile driving continues past civil sunset.
Sound Attenuation Devices
    South Fork Wind would implement sound attenuation technology 
designed to result in an average of 10 dB attenuation of impact pile 
driving noise (see Acoustic Monitoring for Sound Source and Harassment 
Isopleth

[[Page 8527]]

Verification section below). The attenuation system would likely be a 
single bubble curtain, but may include one of the following or some 
combination of the following: A double BBC, Hydro-sound Damper, and/or 
Noise Abatement System. South Fork would also have a second back-up 
attenuation device (e.g., additional bubble curtain or similar) 
available, if needed, to achieve the targeted reduction in noise levels 
that would result in the measured Level A harassment and Level B 
harassment isopleths corresponding to those modeled assuming 10 dB 
attenuation, pending results of sound field verification testing.
    If South Fork Wind uses a bubble curtain, the bubble curtain must 
distribute air bubbles around 100 percent of the piling perimeter for 
the full depth of the water column. The lowest bubble ring shall be in 
contact with the mudline for the full circumference of the ring, and 
the weights attached to the bottom ring shall ensure 100 percent 
mudline contact. No parts of the ring or other objects shall prevent 
full mudline contact. South Fork Wind would require that construction 
contractors train personnel in the proper balancing of airflow to the 
bubblers, and would require that construction contractors submit an 
inspection/performance report for approval by South Fork Wind within 72 
hours following the performance test. Corrections to the attenuation 
device to meet the performance standards would occur prior to impact 
driving. If South Fork Wind uses a noise attenuation device other than 
a BBC, similar quality control measures would be required.

Cofferdam Installation and Removal

Clearance and Exclusion Zones
    South Fork Wind would implement visual monitoring of the clearance 
zones for 30 minutes prior to the initiation of ramp-up of vibratory 
piling equipment (Table 25). During this period, the clearance zone 
will be monitored by the PSOs, using the appropriate visual technology. 
Ramp-up may not be initiated if any marine mammal(s) is detected within 
its respective exclusion zone. If a marine mammal is observed within a 
clearance zone during the pre-clearance period, ramp-up may not begin 
until the animal(s) has been observed exiting its respective clearance 
zone or until an additional time period has elapsed with no further 
sighting (i.e., 15 minutes for small odontocetes and seals, and 30 
minutes for all other species).

    Table 25--Proposed Clearance and Exclusion Zones During Installation and Removal of a Temporary Cofferdam
----------------------------------------------------------------------------------------------------------------
                                      Level A         Level B        Pre-start                        Vessel
             Species                harassment      harassment    clearance zone  Exclusion zone    separation
                                  zone (m) (SEL)  zone (m) (SPL)        (m)             (m)        distance (m)
----------------------------------------------------------------------------------------------------------------
Low-Frequency Cetaceans:
    Fin whale...................           1,470          36,766           1,500           1,500             100
    Minke whale.................           1,470          36,766           1,500           1,500             100
    Sei whale...................           1,470          36,766           1,500           1,500             100
    Humpback whale..............           1,470          36,766           1,500           1,500             100
    North Atlantic right whale..           1,470          36,766           1,500           1,500             500
    Blue whale..................           1,470          36,766           1,500           1,500             100
Mid-Frequency Cetaceans:
    Sperm whale.................  ..............          36,766           1,500           1,500             100
    Atlantic spotted dolphin....  ..............          36,766             100              50              50
    Atlantic white-sided dolphin  ..............          36,766             100              50              50
    Common dolphin..............  ..............          36,766             100              50              50
    Risso's dolphin.............  ..............          36,766             100              50              50
    Bottlenose dolphin..........  ..............          36,766             100              50              50
    Long-finned pilot whale.....  ..............          36,766             100              50              50
High-Frequency Cetaceans:
    Harbor porpoise.............              63          36,766             100             100              50
Phocid Pinnipeds in Water:
    Gray seal...................             103          36,766             150             125              50
    Harbor seal.................             103          36,766             150             125              50
----------------------------------------------------------------------------------------------------------------
SEL = cumulative sound exposure level in units of decibels referenced to 1 micropascal squared second; SPL =
  root-mean-square sound pressure level in units of decibels referenced to 1 micropascal.

Shutdown of Vibratory Pile Driving
    An immediate shutdown of vibratory pile driving equipment must be 
implemented if a marine mammal is sighted entering or within its 
respective exclusion zone after cofferdam installation has commenced. 
Resumption of vibratory pile driving can begin if the animal has been 
observed exiting its respective exclusion zone or an additional time 
period has elapsed without a resighting (i.e., 15 minutes for small 
odontocetes and seals and 30 minutes for all other species). If a 
species for which authorization has not been granted, or, a species for 
which authorization has been granted but the authorized number of takes 
have been met, approaches or is observed within the exclusion zone, 
shutdown would be required.

HRG Surveys

Clearance and Exclusion Zones
    South Fork Wind would implement a 30-minute pre-clearance period of 
the clearance zones prior to the initiation of ramp-up of HRG equipment 
(Table 26). During this period, the clearance zone will be monitored by 
the PSOs, using the appropriate visual technology. Ramp-up may not be 
initiated if any marine mammal(s) is within its respective clearance 
zone. If a marine mammal is observed within a clearance zone during the 
pre-clearance period, ramp-up may not begin until the animal(s) has 
been observed exiting its respective clearance zone or until an 
additional time period has elapsed with no further sighting (i.e., 15 
minutes for small odontocetes and seals, and 30 minutes for all other 
species).

[[Page 8528]]



      Table 26--Proposed Monitoring, Clearance, and Exclusion Zones During HRG Surveys Operating CHIRP Sub-Bottom Profilers, Boomers, and Sparkers
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                            Maximum extent of zone in meters (m) from all potential HRG
                                                                                                   sound sources
                                              Level A         Level A    ----------------------------------------------------------------     Vessel
                 Species                    harassment      harassment             Level B zones                                            separation
                                            zone (SEL)       zone (PK)   --------------------------------    Pre-start                     distance (m)
                                                                                            Boomers and   clearance zone  Exclusion zone
                                                                              CHIRPS         sparkers
--------------------------------------------------------------------------------------------------------------------------------------------------------
Low-Frequency Cetaceans:
    Fin whale...........................              <1              <1              50             141             100             100             100
    Minke whale.........................              <1              <1              50             141             100             100             100
    Sei whale...........................              <1              <1              50             141             100             100             100
    Humpback whale......................              <1              <1              50             141             100             100             100
    N.A. right whale....................              <1              <1              50             141             500             500             500
    Blue whale..........................              <1              <1              50             141             100             100             100
Mid-Frequency Cetaceans:
    Sperm whale.........................              <1              <1              50             141             100             100             100
    Atlantic spotted dolphin............              <1              <1              50             141             100  ..............              50
    Atlantic white-sided dolphin........              <1              <1              50             141             100  ..............              50
    Common dolphin......................              <1              <1              50             141             100  ..............              50
    Risso's dolphin.....................              <1              <1              50             141             100  ..............              50
    Bottlenose dolphin..................              <1              <1              50             141             100  ..............              50
    Long-finned pilot whale.............              <1              <1              50             141             100  ..............              50
High-Frequency Cetaceans:
    Harbor porpoise.....................              37               5              50             141             100             100              50
Phocid Pinnipeds in Water:
    Gray seal...........................              <1              <1              50             141             100  ..............              50
    Harbor seal.........................              <1              <1              50             141             100  ..............              50
--------------------------------------------------------------------------------------------------------------------------------------------------------

Ramp-Up of HRG Survey Equipment
    When practicable, a ramp-up procedure would be used for HRG survey 
equipment capable of adjusting energy levels at the start or restart of 
survey activities. The ramp-up procedure would be used at the beginning 
of HRG survey activities in order to provide additional protection to 
marine mammals near the Survey Area by allowing them to vacate the area 
prior to the commencement of survey equipment operation at full power.
    A ramp-up would begin with the powering up of the smallest acoustic 
HRG equipment at its lowest practical power output appropriate for the 
survey. When practicable, the power would then be gradually turned up 
and other acoustic sources would be added.
    Ramp-up activities will be delayed if a marine mammal(s) enters its 
respective exclusion zone. Ramp-up will continue if the animal has been 
observed exiting its respective exclusion zone or until an additional 
time period has elapsed with no further sighting (i.e, 15 minutes for 
small odontocetes and seals and 30 minutes for all other species).
Shutdown of HRG Survey Equipment
    An immediate shutdown of the impulsive HRG survey equipment would 
be required if a marine mammal is sighted entering or within its 
respective exclusion zone. No shutdown is required for surveys 
operating only non-impulsive acoustic sources. The vessel operator must 
comply immediately with any call for shutdown by the Lead PSO. Any 
disagreement between the Lead PSO and vessel operator should be 
discussed only after shutdown has occurred. Subsequent restart of the 
survey equipment can be initiated if the animal has been observed 
exiting its respective exclusion zone or until an additional time 
period has elapsed (i.e., 15 minutes for small odontocetes and seals 
and 30 minutes for all other species).
    If a species for which authorization has not been granted, or, a 
species for which authorization has been granted but the authorized 
number of takes have been met, approaches or is observed within the 
Level B harassment zone, shutdown would occur.
    If the acoustic source is shut down for reasons other than 
mitigation (e.g., mechanical difficulty) for less than 30 minutes, it 
may be activated again without ramp-up if PSOs have maintained constant 
observation and no detections of any marine mammal have occurred within 
the respective exclusion zones. If the acoustic source is shut down for 
a period longer than 30 minutes and PSOs have maintained constant 
observation, then pre-clearance and ramp-up procedures will be 
initiated as described in the previous section.
    The shutdown requirement would be waived for small delphinids of 
the following genera: Delphinus, Lagenorhynchus, Stenella, and 
Tursiops. Specifically, if a delphinid from the specified genera is 
visually detected approaching the vessel (i.e., to bow ride) or towed 
equipment, shutdown is not required. Furthermore, if there is 
uncertainty regarding identification of a marine mammal species (i.e., 
whether the observed marine mammal(s) belongs to one of the delphinid 
genera for which shutdown is waived), PSOs must use best professional 
judgement in making the decision to call for a shutdown. Additionally, 
shutdown is required if a delphinid is detected in the exclusion zone 
and belongs to a genus other than those specified.

[[Page 8529]]

Vessel Strike Avoidance

    Vessel operators and crews must maintain a vigilant watch for all 
marine mammals and slow down, stop their vessel, or alter course, as 
appropriate and regardless of vessel size, to avoid striking any marine 
mammal. A visual observer aboard the vessel must monitor a vessel 
strike avoidance zone around the vessel (distances stated below). 
Visual observers monitoring the vessel strike avoidance zone may be 
third-party observers (i.e., PSOs) or crew members, but crew members 
responsible for these duties must be provided sufficient training to 
distinguish marine mammals from other phenomena and broadly to identify 
a marine mammal as a right whale, other whale (defined in this context 
as sperm whales or baleen whales other than right whales), or other 
marine mammal. Vessel strike avoidance measures will include, but are 
not limited to, the following, except under circumstances when 
complying with these measures would put the safety of the vessel or 
crew at risk:
     All vessels greater than or equal to 65 ft (19.8 m) in 
overall length must comply with the 10 knot speed restriction in any 
Seasonal Management Area (SMA) per the NOAA ship strike reduction rule 
(73 FR 60173; October 10, 2008).
     Vessels of all sizes will operate port to port at 10 knots 
or less between November 1 and April 30, except for vessels transiting 
inside Narragansett Bay or Long Island Sound.
     A trained, dedicated visual observer and alternative 
visual detection system (e.g., thermal cameras) will be stationed on 
all transiting vessels that intend to operate at greater than 10 knots 
from November 1 through April 30. The primary role of the visual 
observer is to alert the vessel navigation crew to the presence of 
marine mammals and to report transit activities and marine mammal 
sightings to the designated South Fork Wind information system.
     Vessels of all sizes will operate at 10 knots or less in 
any North Atlantic right whale Dynamic Management Area (DMA).
     Outside of DMAs, SMAs, and the November 1 through April 30 
time period, localized detections of North Atlantic right whales, using 
passive acoustics, would trigger a slow-down to 10 knots or less in the 
area of detection (zone) for the following 12 hours (hrs). Each 
subsequent detection would trigger a 12-hr reset. A slow-down in that 
zone expires when there has been no further visual or acoustic 
detection in the past 12-hr within the triggered zone.
     For all vessels greater than or equal to 65 ft (19.8 m) in 
overall length, vessel speeds must be reduced to 10 knots or less when 
mother/calf pairs, pods, or large assemblages of cetaceans are observed 
near a vessel.
     All vessels must maintain a minimum separation distance of 
500 m from North Atlantic right whales. If a whale is observed but 
cannot be confirmed as a species other than a right whale, the vessel 
operator must assume that it is a right whale and take appropriate 
action.
     All vessels must maintain a minimum separation distance of 
100 m from sperm whales and all other baleen whales.
     All vessels must, to the maximum extent practicable, 
attempt to maintain a minimum separation distance of 50 m from all 
other marine mammals, with an exception made for those that approach 
the vessel.
     When marine mammals are sighted while a vessel is 
underway, the vessel must take action as necessary to avoid violating 
the relevant separation distance, e.g., attempt to remain parallel to 
the animal's course, avoid excessive speed or abrupt changes in 
direction until the animal has left the area. If marine mammals are 
sighted within the relevant separation distance, the vessel must reduce 
speed and shift the engine to neutral, not engaging the engines until 
animals are clear of the area. This does not apply to any vessel towing 
gear or any vessel that is navigationally constrained.
     These requirements do not apply in any case where 
compliance would create an imminent and serious threat to a person or 
vessel or to the extent that a vessel is restricted in its ability to 
maneuver and, because of the restriction, cannot comply.
     When not on active watch duty, members of the monitoring 
team must consult NMFS' North Atlantic right whale reporting systems 
for the presence of North Atlantic right whales in the project area.
     Project-specific training must be conducted for all vessel 
crew prior to the start of in-water construction activities. 
Confirmation of the training and understanding of the requirements must 
be documented on a training course log sheet.
    NMFS has carefully evaluated South Fork Wind's proposed mitigation 
measures and considered a range of other measures in the context of 
ensuring that NMFS prescribed the means of effecting the least 
practicable adverse impact on the affected marine mammal species and 
stocks and their habitat. Based on NMFS' evaluation of these measures, 
NMFS has preliminarily determined that the proposed mitigation measures 
provide the means of effecting the least practicable adverse impact on 
marine mammal species or stocks and their habitat, paying particular 
attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of such species or stock for 
subsistence uses.

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).

[[Page 8530]]

     Mitigation and monitoring effectiveness.
    Monitoring would be conducted before, during, and after impact pile 
driving, vibratory pile driving and during HRG surveys. In addition, 
observers will record all incidents of marine mammal occurrence at any 
distance from the piling location or active HRG acoustic source, and 
monitors will document any behavioral reactions in concert with 
distance from an acoustic source. Observations made outside the 
clearance zones will not result in delay of project activities.
    A pile segment or HRG survey trackline may be completed without 
cessation, unless the marine mammal approaches or enters the clearance 
zone, at which point pile driving or survey activities would be halted 
when practicable, as described above.
    The following additional measures apply to visual monitoring:
    (1) Monitoring will be conducted by qualified, trained PSOs, who 
will be placed on the installation (monopile and cofferdam 
installation), secondary observation (monopile installation only), or 
HRG survey vessels, which represents the best vantage point to monitor 
for marine mammals and implement shutdown procedures when applicable;
    (2) PSOs may not exceed 4 consecutive watch hours; must have a 
minimum 2 hour break between watches; and may not exceed a combined 
watch schedule of more than 12 hours in a 24-hour period;
    (3) PSOs will have no other construction-related tasks while 
conducting monitoring;
    (4) PSOs should have the following minimum qualifications:
     Visual acuity in both eyes (correction is permissible) 
sufficient for discernment of moving targets at the water's surface 
with ability to estimate target size and distance; use of binoculars 
may be necessary to correctly identify the target;
     Ability to conduct field observations and collect data 
according to assigned protocols;
     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
     Writing skills sufficient to document observations 
including, but not limited to: The number and species of marine mammals 
observed; dates and times when in-water construction activities were 
conducted; dates and times when in-water construction activities were 
suspended to avoid potential incidental injury of marine mammals from 
construction noise within a defined shutdown zone; and marine mammal 
behavior; and
     Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.
    Observer teams employed by South Fork Wind in satisfaction of the 
mitigation and monitoring requirements described herein must meet the 
following additional requirements:
     Independent observers (i.e., not construction personnel) 
are required;
     At least one observer must have prior experience working 
as an observer;
     Other observers may substitute education (degree in 
biological science or related field) or training for experience;
     One observer will be designated as lead observer or 
monitoring coordinator. The lead observer must have prior experience 
working as an observer; and
     NMFS will require submission and approval of observer 
curriculum vitae.

Visual Marine Mammal Observations

Monopile Installation
    South Fork Wind will collect sighting data and behavioral responses 
to pile driving for marine mammal species observed in the region of 
activity during the period of activity. All observers will be trained 
in marine mammal identification and behaviors and are required to have 
no other construction-related tasks while conducting monitoring. PSOs 
would monitor all clearance zones at all times. PSOs would also monitor 
Level B harassment zones and would document any marine mammals observed 
within these zones, to the extent practicable (noting that some 
distances to these zones are too large to fully observe). South Fork 
Wind would conduct monitoring before, during, and after pile driving, 
with observers located at the best practicable vantage points on the 
pile driving vessel.
    South Fork Wind would implement the following procedures for pile 
driving:
     A minimum of two PSOs on the impact pile driving vessel 
will maintain watch at all times when pile driving is underway.
     A minimum of two PSOs on a secondary PSO vessel located at 
the outer edge of the 2,200 m clearance zone will maintain watch at all 
times when pile driving is underway.
     PSOs would be located at the best vantage point(s) on the 
impact pile driving and secondary vessels to ensure that they are able 
to observe the entire clearance zones and as much of the Level B 
harassment zone as possible.
     During all observation periods, PSOs will use binoculars 
and the naked eye to search continuously for marine mammals.
     PSOs will be provided reticle binoculars, NVDs, and a 
thermal/IR camera system.
     If the clearance zones are obscured by fog or poor 
lighting conditions, pile driving will not be initiated until clearance 
zones are fully visible. Should such conditions arise while impact 
driving is underway, the activity would be halted when practicable, as 
described above.
     The clearance zones will be monitored for the presence of 
marine mammals for 60 mins before, throughout the installation of the 
pile, and for 30 mins after all pile driving activity.
    When monitoring is required during vessel transit (as described 
above), the PSO(s) will be stationed on vessels at the best vantage 
points to ensure maintenance of standoff distances between marine 
mammals and vessels (as described above). South Fork Wind would 
implement the following measures during vessel transit when there is an 
observation of a marine mammal:
     PSOs or dedicated observers will record the vessel's 
position and speed, water depth, sea state, and visibility at the 
beginning and end of each observation period, and whenever there is a 
change in any of those variables that materially affects sighting 
conditions.
    Individuals implementing the monitoring protocol will assess its 
effectiveness using an adaptive approach. PSOs will use their best 
professional judgment throughout implementation and seek improvements 
to these methods when deemed appropriate. Any modifications to the 
protocol will be coordinated between NMFS and South Fork Wind.
Cofferdam Installation and Removal
    The visual monitoring requirements for installation of the 
cofferdam would be consistent with those described for monopile 
installation, differing as follows:
     A minimum of two PSOs on the vibratory pile driving 
platform or construction vessel will maintain watch at all times when 
vibratory pile driving is underway.
     During daytime (i.e., 30 minutes prior to sunrise through 
30 minutes following sunset) observations, one PSO will monitor the 
exclusion zone using naked eye/reticle binoculars; a second PSO will 
also periodically scan outside the exclusion zone, using mounted big 
eye binoculars.

[[Page 8531]]

     During daytime low visibility conditions, one PSO will 
monitor the exclusion zone with a mounted IR camera, while the second 
PSO maintains visual watch using naked eye/reticle binoculars.
     If nighttime observations are required, two PSOs will 
monitor the exclusion zone using a mounted IR camera and hand-held/
wearable NVDs.
HRG Surveys
    The visual monitoring requirements for HRG surveys would be 
consistent with those described for monopile installation, differing as 
follows:
     At least one PSO must be on duty during daylight 
operations on each survey vessel, conducting visual observations at all 
times on all active survey vessels during daylight hours (i.e., from 30 
minutes prior to sunrise through 30 minutes following sunset).
     A minimum of two PSOs must be on watch during nighttime 
operations.
     PSO(s) would ensure 360[deg] visual coverage around the 
vessel from the most appropriate observation posts and would conduct 
visual observations using binoculars and/or NVDs and the naked eye.
     In cases where multiple vessels are surveying 
concurrently, any observations of marine mammals would be communicated 
to PSOs on all nearby survey vessels.

Data Collection

    Among other pieces of information, South Fork Wind will record 
detailed information about any implementation of delays or shutdowns, 
including the distance of animals to the pile and a description of 
specific actions that ensued and resulting behavior of the animal, if 
any. NMFS requires that, at a minimum, the following information be 
collected on the sighting forms:
     Date and time that monitored activity begins or ends;
     Construction activities occurring during each observation 
period;
     Weather parameters (e.g., wind speed, percent cloud cover, 
visibility);
     Water conditions (e.g., sea state, tide state);
     Species, numbers, and, if possible, sex and age class of 
marine mammals;
     Description of any observable marine mammal behavioral 
patterns, including:
    [cir] Bearing and direction of travel and distance from pile 
driving activity,
    [cir] changes in behavioral patterns, noting when/if they 
correspond to change in activity (e.g., turning source on or off), and
    [cir] amount of time spent within Level A and Level B harassment 
zones
     Distance from pile driving activities to marine mammals 
and distance from the marine mammals to the observation point;
     Type of construction activity (e.g., vibratory or impact 
pile driving, HRG survey) and specific phase of activity (e.g., ramp-up 
for HRG survey, HRG acoustic source on/off, soft start for pile 
driving, active pile driving, etc.) when marine mammals are observed.
     Description of implementation of mitigation measures 
(e.g., delay or shutdown).
     Locations of all marine mammal observations; and
     Other human activity in the area.

Marine Mammal Passive Acoustic Monitoring

    South Fork Wind would utilize a PAM system to supplement visual 
monitoring during all pre-clearance, WTG and OSS impact piling 
operations, and post visual monitoring periods. The PAM system would be 
monitored by a minimum of one acoustic PSO beginning at least 60 
minutes prior to soft start of pile driving and at all times during 
pile driving. Acoustic PSOs would immediately communicate all 
detections of marine mammals to visual PSOs, including any 
determination regarding species identification, distance, and bearing 
and the degree of confidence in the determination. PAM would be used to 
inform visual monitoring during construction. The PAM system would not 
be located on the pile installation vessel.
    Acoustic PSOs may be on watch for a maximum of four consecutive 
hours followed by a break of at least two hours between watches, and 
for a maximum of twelve hours per day. Acoustic PSOs would be required 
to complete specialized training for operating PAM systems. PSOs can 
act as acoustic or visual observers (but not simultaneously) as long as 
they demonstrate that their training and experience are sufficient to 
perform each task.

Acoustic Monitoring for Sound Source and Harassment Isopleth 
Verification

    During the first monopile installation, South Fork Wind would be 
required to empirically determine the distances to the isopleths 
corresponding to Level B harassment thresholds either by extrapolating 
from in situ measurements conducted at distances approximately 100 m 
(or less, depending on the position of the noise mitigation system), 
750 m, 1500 m, 3000 m, and 6000 m from the pile being driven, or by 
direct measurements to locate the distance where the received levels 
reach the relevant thresholds or below. Additionally, measurements 
conducted at multiple distances from the pile will be used to estimate 
propagation loss. Isopleths corresponding to the Level B harassment 
threshold would be verified for comparison with the acoustic 
propagation range and R95percent modeled isopleths used to 
estimate proposed authorized take.
    If initial acoustic field measurements indicate distances to the 
isopleths corresponding to Level B harassment thresholds are greater 
than the distances predicted by modeling (as presented in the IHA 
application), South Fork Wind must implement additional sound 
attenuation measures prior to conducting additional pile driving. 
Initial additional measures may include improving the efficacy of the 
implemented noise attenuation technology and/or modifying the piling 
schedule to reduce the sound source. If implementation of these 
corrective actions does not result in distances to the Level B 
harassment isopleths that are similar to or less than those used to 
calculate take, South Fork Wind would install a second noise mitigation 
system to achieve the modelled ranges. Each sequential modification 
would be evaluated empirically by acoustic field measurements.
    If acoustic measurements indicate that distances to isopleths 
corresponding to the Level B harassment threshold are less than the 
distances predicted by modeling (as presented in the IHA application), 
South Fork Wind may request a modification to the clearance and 
exclusion zones for impact pile driving. If modifications are approved 
by NMFS, each sequential modification to decrease zone sizes would also 
be evaluated empirically by acoustic field measurements.

Reporting

    A draft report would be submitted to NMFS within 90 days of the 
completion of monitoring for each installation's in-water work window. 
The report would include marine mammal observations pre-activity, 
during-activity, and post-activity during pile driving days, and would 
also provide descriptions of any changes in marine mammal behavioral 
patterns resulting from construction activities. The report would 
detail the monitoring protocol, summarize the data recorded during 
monitoring including an estimate of the number of marine mammals that 
may have been harassed during the period of the report, and describe 
any mitigation actions taken (i.e., delays or shutdowns due to 
detections of marine mammals, and documentation of when shutdowns

[[Page 8532]]

were called for but not implemented and why). The report would also 
include results from acoustic monitoring including dates and times of 
all detections, types and nature of sounds heard, whether detections 
were linked with visual sightings, water depth of the hydrophone array, 
bearing of the animal to the vessel (if determinable), species or 
taxonomic group (if determinable), spectrogram screenshot, a record of 
the PAM operator's review of any acoustic detections, and any other 
notable information. A final report must be submitted within 30 days 
following resolution of comments on the draft report.
    South Fork Wind would be required to submit a preliminary acoustic 
monitoring report to NMFS within 24 hrs of completing sound source 
verification (SSV) on the first monopile. In addition to in situ 
measured distances to the Level A harassment and Level B harassment 
thresholds, the acoustic monitoring report would include: SPLpk, SPLrms 
that contains 90 percent of the acoustic energy, single strike sound 
exposure level, integration time for SPLrms, SELss spectrum (\1/3\ 
octave band or power density spectra). All these levels would be 
reported in the form of median, mean, max, and minimum. The sound 
levels reported would be in median and linear average (i.e., taking 
averages of sound intensity before converting to dB). The acoustic 
monitoring report would also include a description of the hydrophones 
used, hydrophone and water depth, distance to the pile driven, and 
sediment type at the recording location.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any responses (e.g., intensity, duration), the context 
of any responses (e.g., critical reproductive time or location, 
migration), as well as effects on habitat, and the likely effectiveness 
of the mitigation. NMFS also assesses the number, intensity, and 
context of estimated takes by evaluating this information relative to 
population status. Consistent with the 1989 preamble for NMFS's 
implementing regulations (54 FR 40338; September 29, 1989), the impacts 
from other past and ongoing anthropogenic activities are incorporated 
into this analysis via their impacts on the environmental baseline 
(e.g., as reflected in the regulatory status of the species, population 
size and growth rate where known, ongoing sources of human-caused 
mortality, or ambient noise levels).
    Pile driving and HRG survey activities associated with the proposed 
project, as described previously, have the potential to disturb or 
temporarily displace marine mammals. Specifically, the specified 
activities may result in take, in the form of Level A harassment 
(potential injury; from impact pile driving only) or Level B harassment 
(potential behavioral disturbance) from underwater sounds generated 
from pile driving (impact and vibratory) and certain HRG active 
acoustic sources. Potential takes could occur if individual marine 
mammals are present in the ensonified zone when pile driving or HRG 
survey activities are occurring.
    To avoid repetition, the majority of our analyses apply to all the 
species listed in Table 3, given that many of the anticipated effects 
of the proposed project on different marine mammal stocks are expected 
to be relatively similar in nature. Where there are meaningful 
differences between species or stocks--as is the case of the North 
Atlantic right whale--they are included as separate subsections below.

North Atlantic Right Whales

    North Atlantic right whales are currently threatened by low 
population abundance, higher than normal mortality rates and lower than 
normal reproductive rates. As described above, the project area 
represents part of an important migratory area for North Atlantic right 
whales, which make annual migrations up and down the Atlantic coast. 
Due to the current status of North Atlantic right whales, and the 
spatial overlap of the proposed project with an area of biological 
significance for North Atlantic right whales, the potential impacts of 
the proposed project on North Atlantic right whales warrant particular 
attention.
    As described above, North Atlantic right whale presence in the 
project area is largely seasonal. As a result of several years of 
aerial surveys and PAM deployments in the area, NMFS has confidence 
that North Atlantic right whales are expected in the project area 
predominately during certain times of year while at other times of year 
North Atlantic right whales are expected to occur less frequently in 
the project area. During aerial surveys conducted from 2011-2015 in the 
project area, North Atlantic right whale sightings occurred only 
December through April, with no sightings from May through November 
(Kraus et al., 2016). There was not significant variability in sighting 
rate among years, indicating consistent annual seasonal use of the area 
by North Atlantic right whales over the timespan of the surveys (Kraus 
et al., 2016). However, as described previously, North Atlantic right 
whale presence is increasingly variable in identified core habitats, 
including the area south of Martha's Vineyard and Nantucket islands 
(northeast of the proposed SFWF) where both visual and acoustic 
detections of North Atlantic right whales indicate a nearly year-round 
presence (Oleson et al., 2020), although seasonal trends are still 
prominent (Hayes et al., 2020).
    Due to this seasonal pattern in North Atlantic right whale 
occurrence in the project area, NMFS expects the most significant 
measure in minimizing impacts to North Atlantic right whales to be the 
proposed seasonal closure that would occur from January through April, 
when North Atlantic right whale abundance in the project area is 
greatest. In addition, proposed mitigation measures outside of those 
months--including a 5 km clearance zone facilitated through PAM and 
PSOs--will greatly minimize any takes that may otherwise occur outside 
of the months of peak abundance in the area. As a result of these 
mitigation measures, NMFS expects the already small potential for North 
Atlantic right whales to be exposed to project-related sound above the 
Level A harassment threshold to be eliminated. Therefore, South Fork 
did not request nor is NMFS proposing to authorize take by Level A 
harassment. NMFS also expects these proposed measures to greatly reduce 
the amount of exposures to project-related noise above the Level B 
harassment threshold, and the duration and intensity of any exposures 
above the Level B harassment threshold that do occur. No serious injury 
or mortality of North Atlantic right whales would be expected even in 
the absence of the proposed mitigation measures.
    Instances of Level B harassment of North Atlantic right whales will 
be reduced to the level of least practicable adverse impact through use 
of proposed mitigation measures, including soft start

[[Page 8533]]

and exclusion zones larger than the Level A harassment zone. Any 
individuals that are exposed above the Level B harassment threshold are 
expected to move away from the sound source and temporarily avoid the 
areas of pile driving. Therefore, North Atlantic right whales taken by 
the activity are likely to be exposed to lower noise levels (closer to 
the 120dB threshold than the Level A harassment threshold) and 
therefore, behavioral reactions are expected to be less intense than 
during exposures to louder sounds (but still below the Level A 
harassment threshold). NMFS expects that any avoidance of the project 
area by North Atlantic right whales would be temporary in nature and 
that any North Atlantic right whales that avoid the project area during 
construction would not be permanently displaced. Even limited repeated 
Level B harassment of some small subset of the overall stock, although 
not expected to occur given the transitory nature of marine mammals in 
the project area, is unlikely to result in any significant realized 
decrease in fitness or viability for the affected individuals, and thus 
would not result in any adverse impact to the stock as a whole.
    Prey for North Atlantic right whales are mobile and broadly 
distributed throughout the project area; therefore, North Atlantic 
right whales that may be temporarily displaced during construction 
activities are expected to be able to resume foraging once they have 
moved away from areas with disturbing levels of underwater noise. 
Because of the temporary nature of the disturbance and the availability 
of similar habitat and resources in the surrounding area, the impacts 
to North Atlantic right whales and the food sources that they utilize 
are not expected to cause significant or long-term consequences for 
individual North Atlantic right whales or their population. In 
addition, there are no North Atlantic right whale mating or calving 
areas within the proposed project area.
    As described above, North Atlantic right whales are experiencing an 
ongoing UME. However, as described above, no injury of North Atlantic 
right whales as a result of the proposed project is expected or 
proposed for authorization, and Level B harassment takes of North 
Atlantic right whales are expected to be in the form of avoidance of 
the immediate area of construction. As no injury or mortality is 
expected or proposed for authorization, and Level B harassment of North 
Atlantic right whales will be reduced to the level of least practicable 
adverse impact through use of proposed mitigation measures, the 
proposed authorized takes of North Atlantic right whales would not 
exacerbate or compound the effects of the ongoing UME in any way.
    NMFS concludes that the additional proposed mitigation measures 
would ensure that any exposures above the Level B harassment threshold 
would result in only short-term effects to individuals exposed. With 
implementation of the proposed mitigation requirements, take by Level A 
harassment is unlikely and is therefore not proposed for authorization. 
Potential impacts associated with Level B harassment would include only 
low-level, temporary behavioral modifications, most likely in the form 
of avoidance behavior or potential alteration of vocalizations.
    Although acoustic masking may occur, based on the acoustic 
characteristics of noise associated with impact pile driving (e.g., 
frequency spectra, short duration) and HRG surveys (e.g., higher 
frequency, intermittent signals) and the limited duration of vibratory 
pile driving activity, NMFS expects masking effects to be minimal 
(e.g., pile driving) to none (e.g., HRG surveys). As mentioned 
previously, masking events that might be considered Level B harassment 
have already been accounted for in the exposure analysis as they would 
be expected to occur within the behavioral harassment zones 
predetermined for pile driving. Avoidance of the SFWF or SFEC during 
construction would represent a potential manifestation of behavioral 
disturbance. Although the project area is located within the migratory 
BIA for North Atlantic right whales, impact pile driving of monopile 
foundations would only occur on 16 days (one pile would be driven per 
day for a maximum of 3 hours), and vibratory pile driving would be 
limited to a maximum of 36 hours of the 12-month project. Further, 
seasonal restrictions preclude impact pile driving during the months in 
which North Atlantic right whale occurrence is expected to be highest 
(January through April). If avoidance of the project area by North 
Atlantic right whales occurs, it is expected to be temporary. Finally, 
consistent North Atlantic right whale utilization of the habitat south 
of Martha's Vineyard and Nantucket Islands (Oleson et al., 2020) 
indicates that suitable alternative nearby habitat would be available 
to North Atlantic right whales that might avoid the project area during 
construction.
    In order to evaluate whether or not individual behavioral 
responses, in combination with other stressors, impact animal 
populations, scientists have developed theoretical frameworks which can 
then be applied to particular case studies when the supporting data are 
available. One such framework is the population consequences of 
disturbance model (PCoD), which attempts to assess the combined effects 
of individual animal exposures to stressors at the population level 
(NAS 2017). Nearly all PCoD studies considering multiple marine mammal 
species and experts agree that infrequent exposures of a single day or 
less are unlikely to impact individual fitness, let alone lead to 
population level effects (Booth et al., 2016; Booth et al., 2017; 
Christiansen and Lusseau 2015; Farmer et al., 2018; Harris et al., 
2017; Harwood et al., 2014; Harwood and Booth 2016; King et al., 2015; 
McHuron et al., 2018; NAS 2017; New et al., 2014; Pirotta et al., 2018; 
Southall et al., 2007; Villegas-Amtmann et al., 2015). Since NMFS 
expects that any exposures would be brief (no more than 3 hours per day 
for impact pile driving or 36 hours over 6 days for vibratory pile 
driving, and likely less given probable avoidance response), and repeat 
exposures to the same individuals are unlikely, any behavioral 
responses that would occur due to animals being exposed to construction 
activity are expected to be temporary, with behavior returning to a 
baseline state shortly after the acoustic stimuli ceases, similar to 
findings during European wind farm construction. Given this, and NMFS' 
evaluation of the available PCoD studies, any such behavioral responses 
are not expected to impact individual animals' health or have effects 
on individual animals' survival or reproduction, thus no detrimental 
impacts at the population level are anticipated. North Atlantic right 
whales may temporarily avoid the immediate area but are not expected to 
permanently abandon the area. NMFS does not anticipate North Atlantic 
right whales takes that would result from the proposed project would 
impact annual rates of recruitment or survival. Thus, any takes that 
occur would not result in population level impacts.

All Other Marine Mammal Species

    Impact pile driving has source characteristics (short, sharp pulses 
with higher peak levels and sharper rise time to reach those peaks) 
that are potentially injurious or more likely to produce severe 
behavioral reactions. No Level A harassment from HRG surveys or 
vibratory pile driving is expected, even in the absence of mitigation; 
therefore, our discussion regarding auditory injury is limited to 
impact pile driving.

[[Page 8534]]

Modeling indicates there is limited potential for auditory injury to 
humpback whales during pile driving even in the absence of the proposed 
mitigation measures; the remaining fifteen species are predicted to 
experience no Level A harassment, based on modeling results that 
assumed 10 dB attenuation (Table 16).
    NMFS expects that any exposures above the Level A harassment 
threshold would be in the form of slight PTS, i.e. minor degradation of 
hearing capabilities within regions of hearing that align most 
completely with the energy produced by pile driving (i.e. the low-
frequency region below 2 kHz), not severe hearing impairment. If 
hearing impairment occurs, it is most likely that the affected animal 
would lose a few decibels in its hearing sensitivity, which in most 
cases is not likely to meaningfully affect its ability to forage and 
communicate with conspecifics, much less impact reproduction or 
survival.
    Additionally, the number of Level A harassment takes proposed for 
authorization are relatively low for all marine mammal stocks and 
species: For three of the stocks, only one take by Level A harassment 
is proposed for authorization (i.e., fin whale, sei whale, and minke 
whale), and for most of the remaining stocks, NMFS does not propose to 
authorize any takes by Level A harassment over the duration of the 
project; for the remaining stock (i.e., humpback whale), NMFS proposes 
to authorize four takes by Level A harassment. As described above, any 
PTS incurred would be no more than a few decibels of lost hearing 
sensitivity that would not impact annual rates of recruitment or 
survival for any individual.
    Repeated exposures of individuals to relatively low levels of sound 
outside of preferred habitat areas are unlikely to significantly 
disrupt critical behaviors. Thus, 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. Level B harassment will be reduced to the level of 
least practicable adverse impact through use of proposed mitigation 
measures and, if sound produced by project activities is sufficiently 
disturbing, marine mammals are likely to simply avoid the area while 
the activity is occurring. Therefore, NMFS expects that animals 
disturbed by project sound would likely move away from the sound source 
during project activities in favor of other, similar habitats. NMFS 
expects that any avoidance of the project area by marine mammals would 
be temporary in nature and that any marine mammals that avoid the 
project area during construction would not be permanently displaced.
    Feeding behavior is not likely to be significantly impacted, as 
prey species are mobile and are broadly distributed throughout the 
project area; therefore, marine mammals that may be temporarily 
displaced during construction activities are expected to be able to 
resume foraging once they have moved away from areas with disturbing 
levels of underwater noise. Because of the temporary nature of the 
disturbance and the availability of similar habitat and resources in 
the surrounding area, the impacts to marine mammals and the food 
sources that they utilize are not expected to cause significant or 
long-term consequences for individual marine mammals or their 
populations. There are no areas of notable biological significance for 
marine mammal feeding known to exist in the project area. In addition, 
there are no rookeries or mating or calving areas known to be 
biologically important to marine mammals within the proposed project 
area.
    NMFS concludes that exposures to marine mammals due to the proposed 
project would result in only short-term effects to individuals exposed. 
Marine mammals may temporarily avoid the immediate area but are not 
expected to permanently abandon the area. Impacts to breeding, feeding, 
sheltering, resting, or migration are not expected, nor are shifts in 
habitat use, distribution, or foraging success. NMFS does not 
anticipate the marine mammal takes that would result from the proposed 
project would impact annual rates of recruitment or survival.
    As described above, humpback whales, minke whales, and gray and 
harbor seals are experiencing ongoing UMEs. For minke whales, although 
the ongoing UME is under investigation (as occurs for all UMEs), this 
event does not provide cause for concern regarding population level 
impacts, as the likely population abundance is greater than 20,000 
whales. With regard to humpback whales, 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 DPS) remains healthy. The West Indies DPS, which 
consists of the whales whose breeding range includes the Atlantic 
margin of the Antilles from Cuba to northern Venezuela, and whose 
feeding range primarily includes the Gulf of Maine, eastern Canada, and 
western Greenland, was delisted. The status review identified harmful 
algal blooms, vessel collisions, and fishing gear entanglements as 
relevant threats for this DPS, but noted that all other threats are 
considered likely to have no or minor impact on population size or the 
growth rate of this DPS (Bettridge et al., 2015). As described in 
Bettridge et al. (2015), the West Indies DPS has a substantial 
population size (i.e., approximately 10,000; Stevick et al., 2003; 
Smith et al., 1999; Bettridge et al., 2015), and appears to be 
experiencing consistent growth. With regard to gray seals and harbor 
seals, although the ongoing UME is under investigation, 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., 
2020). For gray seals, the population abundance is over 500,000, and 
abundance is likely increasing in the U.S. Atlantic EEZ and in Canada 
(Hayes et al., 2020). Proposed authorized takes by Level A harassment 
of humpback whales are low (i.e., no more than four takes by Level A 
harassment proposed for authorization) and, as described above, any 
Level A harassment would be expected to be in the form of slight PTS, 
i.e. minor degradation of hearing capabilities which is not likely to 
meaningfully affect the ability to forage or communicate with 
conspecifics. No serious injury or mortality is expected or proposed 
for authorization, and Level B harassment of humpback whales and minke 
whales and gray and harbor seals will be reduced to the level of least 
practicable adverse impact through use of proposed mitigation measures. 
As such, the proposed authorized takes of these species would not 
exacerbate or compound the effects of the ongoing UMEs on the 
populations.
    In summary and as described above, the following factors primarily 
support NMFS' 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 
for authorization;
     No Level A harassment of North Atlantic right whales would 
occur and Level B harassment will be minimized via extended mitigation 
measures;
     The anticipated impacts of the proposed activity on marine 
mammals would be temporary behavioral changes (primarily avoidance of 
the project area) and limited instances of Level A

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harassment of humpback whales in the form of a slight PTS;
     Potential instances of exposure above the Level A 
harassment threshold are limited to four of the 16 species expected to 
occur in the project area and are expected to be relatively low, and 
the severity of any PTS would be minimized by proposed mitigation 
measures including clearance zones;
     The availability of alternate areas of similar habitat 
value for marine mammals to temporarily vacate the project area during 
the proposed project to avoid exposure to sounds from the activity;
     Effects on species that serve as prey species for marine 
mammals from the proposed project are expected to be short-term and are 
not expected to result in significant or long-term consequences for 
individual marine mammals, or to contribute to adverse impacts on their 
populations;
     There are no known important feeding, breeding or calving 
areas in the project area. A biologically important migratory area 
exists for North Atlantic right whales; however, the proposed seasonal 
moratorium on construction is expected to largely avoid impacts to the 
North Atlantic right whale migration, as described above.
     The proposed mitigation measures, including visual and 
acoustic monitoring, clearance and exclusion zones, soft start (pile 
driving only), ramp up (HRG only), shutdown, are designed to reduce 
frequency and intensity of exposures and are, therefore, expected to 
minimize potential impacts to marine mammals.
     Total proposed authorized takes as a percentage of 
population are very low for all species and stocks (i.e., less than 3.5 
percent for four stocks, and less than 1 percent for the remaining 12 
stocks);
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the proposed activity will have a negligible impact on 
all affected marine mammal species or stocks.

Small Numbers

    As noted above, only small numbers of incidental take may be 
authorized under sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether an authorization is limited to 
small numbers of marine mammals. When the predicted number of 
individuals to be taken is less than one third of the species or stock 
abundance, the take is considered to be of small numbers. Additionally, 
other qualitative factors may be considered in the analysis, such as 
the temporal or spatial scale of the activities.
    NMFS proposes to authorize incidental take of 16 marine mammal 
stocks. The total amount of taking proposed for authorization is less 
than 3.5 percent for four of these stocks, and less than 1 percent for 
the 12 remaining stocks (Table 23), which NMFS preliminarily finds are 
small numbers of marine mammals relative to the estimated overall 
population abundances for those stocks.
    Based on the analysis contained herein of the proposed activity 
(including the proposed mitigation and monitoring measures) and the 
anticipated take of marine mammals, NMFS preliminarily finds that small 
numbers of marine mammals will be taken relative to the population size 
of all 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

    Section 7(a)(2) of the ESA (16 U.S.C. 1531 et seq.) requires that 
each Federal agency insure that any action it authorizes, funds, or 
carries out is not likely to jeopardize the continued existence of any 
endangered or threatened species or result in the destruction or 
adverse modification of designated critical habitat. To ensure ESA 
compliance for the issuance of IHAs, NMFS consults internally whenever 
we propose to authorize take for endangered or threatened species.
    NMFS is proposing to authorize take of North Atlantic right, fin, 
sei, and sperm whales, which are listed under the ESA. The NMFS Office 
of Protected Resources has requested initiation of Section 7 
consultation with the NMFS Greater Atlantic Regional Fisheries Office 
for the issuance of this IHA. NMFS will conclude the ESA 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 South Fork Wind for conducting construction activities 
southeast of Rhode Island for a period of one year, provided the 
previously mentioned mitigation, monitoring, and reporting requirements 
are incorporated. A draft of the proposed IHA can be found at: 
www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.

Request for Public Comments

    NMFS requests comment on the analyses, the proposed authorization, 
and any other aspect of this Notice of Proposed IHA for the proposed 
construction of the South Fork Wind offshore wind project. NMFS also 
requests comment on the potential for renewal of this proposed IHA as 
described in the paragraph below. Please include with your comments any 
supporting data or literature citations to help inform NMFS' final 
decision on the request for MMPA authorization.
    On a case-by-case basis, NMFS may issue a one-time, 1 year IHA 
renewal with an expedited public comment period (15 days) when: (1) 
Another year of identical or nearly identical activities as described 
in the Specified Activities section is planned or (2) the activities 
would not be completed by the time the IHA expires and a second IHA 
would allow for completion of the activities beyond that described in 
the Dates and Duration section, provided all of the following 
conditions are met:
     A request for renewal is received no later than 60 days 
prior to expiration of the current IHA;
     The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
proposed Renewal are identical to the activities analyzed under the 
initial IHA, are a subset of the activities, or include changes so 
minor (e.g., reduction in pile size) that the changes do not affect the 
previous analyses, mitigation and monitoring requirements, or take 
estimates (with the exception of reducing the type or amount of take 
because only a subset of the initially analyzed activities remain to be 
completed under the Renewal); and
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do

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not indicate impacts of a scale or nature not previously analyzed or 
authorized;
     Upon review of the request for renewal, the status of the 
affected species or stocks, and any other pertinent information, NMFS 
determines that there are no more than minor changes in the activities, 
the mitigation and monitoring measures will remain the same and 
appropriate, and the findings in the initial IHA remain valid.

    Dated: January 29, 2021.
Donna Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2021-02263 Filed 2-4-21; 8:45 am]
BILLING CODE 3510-22-P