8490 Federal Register / Vol. 86, No. 23 / Friday, February 5, 2021 / Notices 

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. 

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 ITP.Esch@noaa.gov. 

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-undermarine-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-undermarine-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-windfarm-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 


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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 inwater 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 interarray 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 (km2) (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 


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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 


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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/renewableenergy/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 


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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 counterrotating 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 

Pile driving 

method Pile size Number of piles Strikes/pile Duration/pile Number of piling days 

Impact ........... 11 m monopile ................ 16 Standard pile: 4,500 ........

Difficult pile: 8,000 ...........

Standard pile: 140 min ....

Difficult pile: 250 min .......

Standard scenario: 30. 

Maximum scenario: 20. 


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TABLE 1—SUMMARY OF PILE DRIVING ACTIVITIES FOR SFWF AND SFEC—Continued 

Pile driving 

method Pile size Number of piles Strikes/pile Duration/pile Number of piling days 

Vibratory ....... 19.5 m long/0.95 cm thick 

Sheet pile.

* 80 .......................................... 18 hours ..........................

18 hours ..........................

Installation: 1–3. 

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 HighIntensity 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 fanshaped pattern orthogonally to the 

ship’s direction. 

• Seafloor imaging (sidescan sonar) 

for seabed sediment classification 

purposes, to identify natural and manmade 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

HRG equipment 

category Specific HRG equipment 

Operating 

frequency 

range (kHz) 

Source level 

(dB rms) 

Source level 

(dB 0-peak) 

Beamwidth 

(degrees) 

Typical 

pulse 

duration 

(ms) 

Pulse 

repetition 

rate 

Shallow Sub-bottom 

Profilers.

ET 216 (2000DS or 3200 top 

unit).

2–16 

2–8 

195 – 24 20 6 

ET 424 ..................................... 4–24 176 – 71 3.4 2 

ET 512 ..................................... 0.7–12 179 – 80 9 8 


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TABLE 2—SUMMARY OF REPRESENTATIVE HRG SURVEY EQUIPMENT—Continued 

HRG equipment 

category Specific HRG equipment 

Operating 

frequency 

range (kHz) 

Source level 

(dB rms) 

Source level 

(dB 0-peak) 

Beamwidth 

(degrees) 

Typical 

pulse 

duration 

(ms) 

Pulse 

repetition 

rate 

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, 

500 J) 1.

0.3–1.2 203 211 Omni 1.1 4

AA, Dura-spark UHD 

(400+400) 1.

0.3–1.2 203 211 Omni 1.1 4

GeoMarine, Geo-Source or 

similar dual 400 tip sparker 

(≤800 J) 1.

0.4–5 203 211 Omni 1.1 2

GeoMarine Geo-Source 200 tip 

light weight sparker (400 J) 1.

0.3–1.2 203 211 Omni 1.1 4

GeoMarine Geo-Source 200– 

400 tip freshwater sparker 

(400 J) 1.

0.3–1.2 203 211 Omni 1.1 4

AA, triple plate S-Boom (700– 

1,000 J) 2.

0.1–5 205 211 80 0.6 4

– = not applicable; NR = not reported; AA = Applied Acoustics; dB = decibel; ET = EdgeTech; J = joule; Omni = omnidirectional source. 1The 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/marinemammal-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/findspecies). 

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.), shortfinned pilot whale (Globicephala 

macrorhynchus), pantropical spotted 

dolphin (Stenella attenuata), Fraser’s 

dolphin (Lagenodelphis hosei), whitebeaked 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 


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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/marinemammal-stock-assessments. 

TABLE 3—MARINE MAMMALS KNOWN TO OCCUR IN THE PROJECT AREA THAT MAY BE AFFECTED BY SOUTH FORK

WIND’S PROPOSED ACTIVITY

Common name 

(scientific name) Stock 

MMPA 

and ESA 

status; 

strategic 

(Y/N) 1

Stock abundance 

(CV, Nmin, most recent 

abundance survey) 2

PBR 3 Annual 

M/SI 3

Occurrence and seasonality 

in project area 

Toothed whales (Odontoceti) 

Sperm whale (Physeter macrocephalus) .... North Atlantic ............. E; Y 4,349 (0.28; 3,451; 2016) ... 3.9 0 Rare. 

Long-finned pilot whale (Globicephala 

melas).

W North Atlantic ........ --; N 39,215 (0.3; 30,627; 2016) 306 21 Rare. 

Atlantic spotted dolphin (Stenella frontalis) W North Atlantic ........ --; N 39,921 (0.27; 32,032; 2016) 320 0 Rare. 

Atlantic white-sided dolphin 

(Lagenorhynchus acutus).

W North Atlantic ........ --; N 93,233 (0.71; 54,443; 2016) 544 26 Common year round. 

Bottlenose dolphin (Tursiops truncatus) ..... W North Atlantic, Offshore.--; N 62,851 (0.23; 51,914; 2019) 519 28 Common year round. 

Common dolphin (Delphinus delphis) ......... W North Atlantic ........ --; N 172,974 (0.21; 145,216; 

2016).

1,452 399 Common year round. 

Risso’s dolphin (Grampus griseus) ............. W North Atlantic ........ --; N 35,493 (0.19; 30,298; 2016) 303 54.3 Rare. 

Harbor porpoise (Phocoena phocoena) ...... Gulf of Maine/Bay of 

Fundy.

--; N 95,543 (0.31; 74,034; 2019) 851 217 Common year round. 

Baleen whales (Mysticeti) 

Blue whale (Balaenotpera musculus) ......... W North Atlantic ........ E; Y ukn (unk; 402; 2008) .......... 0.8 0 Rare. 

North Atlantic right whale (Eubalaena 

glacialis).

W North Atlantic ........ E; Y 412 (0; 418; 2018) .............. 0.8 18.6 Year round in continental 

shelf and slope waters, 

occur seasonally. 

Humpback whale (Megaptera 

novaeangliae).

Gulf of Maine ............. --; N 1,393 (0.15; 1,375; 2016) ... 22 58 Common year round. 

Fin whale (Balaenoptera physalus) ............ W North Atlantic ........ E; Y 6,802 (0.24; 5,573; 2016) ... 11 2.35 Year round in continental 

shelf and slope waters, 

occur seasonally. 

Sei whale (Balaenoptera borealis) .............. Nova Scotia ............... E; Y 6,292 (1.02; 3,098 ; 2016) .. 6.2 1.2 Year round in continental 

shelf and slope waters, 

occur seasonally. 

Minke whale (Balaenoptera acutorostrata) Canadian East Coast --; N 21,968 (0.31; 17,002; 2016) 170 10.6 Year round in 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; 2016) 1,389 4,729 Common year round. 

Harbor seal (Phoca vitulina) ....................... W North Atlantic ........ --; N 75,834 (0.15; 66,884; 2012) 2,006 350 Common year round. 

1ESA 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. 2Stock 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. 3Potential 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 


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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 yearround 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 welldocumented 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-northatlantic-right-whale-unusual-mortalityevent. 

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 MidAtlantic Bight as Mid-Atlantic U.S. 


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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-mortalityevent-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 


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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° 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-eventalong-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 worldwide 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 


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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° 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-englandmid-atlantic/marine-life-distress/2018- 

2019-pinniped-unusual-mortality-eventalong. 

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 lowfrequency 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 whales) ..................................................................................................................... 7 Hz to 35 kHz. 


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TABLE 4—MARINE MAMMAL HEARING GROUPS—Continued 

[NMFS, 2018] 

Hearing group Generalized 

hearing range * 

Mid-frequency (MF) cetaceans (dolphins, toothed whales, beaked whales, bottlenose whales) ........................................... 150 Hz to 160 kHz. 

High-frequency (HF) cetaceans (true porpoises, Kogia, river dolphins, cephalorhynchid, Lagenorhynchus cruciger & L. 

australis).

275 Hz to 160 kHz. 

Phocid pinnipeds (PW) (underwater) (true seals) ................................................................................................................... 50 Hz to 86 kHz. 

Otariid pinnipeds (OW) (underwater) (sea lions and fur seals) .............................................................................................. 60 Hz to 39 kHz. 

* 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 

(Hemila ̈ 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 lowfrequency cetaceans (i.e., all mysticete 

species), seven are classified as midfrequency 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 (mPa)), 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 mPa), while the received 

level is the SPL at the listener’s position 

(referenced to 1 mPa). 

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 micropascalsquared second (mPa2-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 


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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. Humangenerated 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 nonimpulsive 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; Go ̈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 


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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, 


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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 


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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 fiveday 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-pituitaryadrenal 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 highfrequency 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 


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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 mPa 

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 mPa. 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 repopulated 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 


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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 repopulation 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 mPa2 s; re 1 

mPa) 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, shortterm 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 


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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 km2) 

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. 


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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 mPa (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 nonimpulsive). The components of South 

Fork Wind’s proposed activity that may 

result in take of marine mammals 

include the use of impulsive and nonimpulsive 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-technicalguidance. 


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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; LE,LF,24h: 183 dB ......................... Cell 2: LE,LF,24h: 199 dB. 

Mid-Frequency (MF) Cetaceans ...................................... Cell 3: Lpk,flat: 230 dB; LE,MF,24h: 185 dB ........................ Cell 4: LE,MF,24h: 198 dB. 

High-Frequency (HF) Cetaceans ..................................... Cell 5: Lpk,flat: 202 dB; LE,HF,24h: 155 dB ........................ Cell 6: LE,HF,24h: 173 dB. 

Phocid Pinnipeds (PW) (Underwater) ............................. Cell 7: Lpk,flat: 218 dB; LE,PW,24h: 185 dB ....................... Cell 8: LE,PW,24h: 201 dB. 

Otariid Pinnipeds (OW) (Underwater) ............................. Cell 9: Lpk,flat: 232 dB; LE,OW,24h: 203 dB ....................... Cell 10 : LE,OW,24h: 219 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 μPa, and cumulative sound exposure level (LE) has a reference value of 1μPa2s. 

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

Energy level (kilojoule[kJ]) 

Standard 

pile strike 

count 

(4,500 total) 

Difficult 

pile strike 

count 

(8,000 total) 

Pile 

penetration 

(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-undermarine-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 


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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 rangedependent acoustic model (FWRAM), 

which is JASCO’s acoustic propagation 

model capable of producing timedomain 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 maximumover-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 & Lu ̈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 & Lu ̈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, Da ̈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, 


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

Marine mammal hearing group Threshold SPLpk

(dB re 1 μPa) 

Mean distance (m) to threshold 

0 dB 

attenuation 

6 dB 

attenuation 

10 dB 

attenuation 

12 dB 

attenuation 

15 dB 

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 μPa = 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*) 

Marine mammal hearing group 

Threshold 

SELcum

(dB re 1 

μPa2s) 

Mean distance (m) to threshold 

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 ..................... 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 μPa2 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

Threshold SPLrms (dB re 1 μPa) 

Mean distance (m) to threshold 

0 dB 

attenuation 

6 dB 

attenuation 

10 dB 

attenuation 

12 dB 

attenuation 

15 dB 

attenuation 

160 ....................................................................................... 11,382 6,884 4,684 4,164 3,272 

dB re 1 μPa = decibel referenced to 1 micropascal. 


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8514 Federal Register / Vol. 86, No. 23 / Friday, February 5, 2021 / Notices 

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 *) 

Species 

ER95% to SELcum thresholds (m) 

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 μPa2 s = decibel referenced to 1 micropascal squared second. 

* Approximation. 

1There 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 (nonimpulsive 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. 


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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

Marine mammal hearing group 

Level A threshold 

SELcum

(dB re 1 μPa2 s) 

Maximum distance 

(m) to Level A 

threshold 

Level B threshold 

SPLrms

(dB re 1 μPa) 

Maximum distance 

(m) to Level B 

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 μPa = decibel referenced to 1 micropascal; μPa2 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

Source 

Distance to Level A threshold (m) Distance to 

Level B (m) 

LF 

(SELcum

threshold) 

MF 

(SELcum

threshold) 

HF 

(SELcum

threshold) 

HF 

(SPL0-pk

threshold) 

PW 

(SELcum

threshold) 

All species 

(160 dB 

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; μPa = 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 μPa2 s; SPL0-pk = zero to peak sound pressure level in dB re 1 μPa; TB = 

teledyne benthos; UHD = ultra-high definition; USBL = ultra-short baseline. 


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8516 Federal Register / Vol. 86, No. 23 / Friday, February 5, 2021 / Notices 

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/km2) 

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 mPa (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 km2 [38.6 miles2]) to units 

of density (animals/km2). 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

Common name 

Monthly density (animals km-2) 

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. 


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Federal Register / Vol. 86, No. 23 / Friday, February 5, 2021 / Notices 8517 

Cofferdam Installation and Removal 

Marine mammal densities in the near 

shore export cable area were estimated 

from the 10 × 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. 

1Only species with potential exposures are listed. 

HRG Surveys 

Densities for HRG surveys were 

combined for the wind farm area (interarray 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] 

Species Jan Feb Mar Apr May Jun July Aug Sept Oct Nov Dec Annual 

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 


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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 rerunning 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. 


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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

Species 

0 dB 

attenuation 

6 dB 

attenuation 

10 dB 

attenuation 

12 dB 

attenuation 

15 dB 

attenuation 

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. 1The 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). 2Subset of fin whale behaviors used to approximate model parameters. 

3Fin whale used as proxy species for exposure modeling. 

4Subset of sperm whale and Atlantic spotted dolphin behaviors used to approximate model parameters. 

5Subset 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

Species 

Level B exposures by noise attenuation level 

0 dB 

attenuation 

6 dB 

attenuation 

10 dB 

attenuation 

12 dB 

attenuation 

15 dB 

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 2 ........................................... 16 7 4 3 3 

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 4 ........................................ 322 152 107 85 48 

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. 


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1The 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). 2Subset of fin whale behaviors used to approximate model parameters. 

3Fin whale used as proxy species for exposure modeling. 

4Subset of sperm whale and Atlantic spotted dolphin behaviors used to approximate model parameters. 

5Subset 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

Species/stock Abundance 

estimate 

Proposed takes 1

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 

1Parentheses 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 


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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 = pr2, 

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 

km2 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 


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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

Species/stock Population 

estimate 

Proposed 

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 + pr2

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. 


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TABLE 21—MODELED LEVEL B HARASSMENT EXPOSURES SPECIES RESULTING FROM HIGH RESOLUTION GEOPHYSICAL

SURVEYS OF THE SFWF AND SFEC 

Species Population 

estimate 

Estimated 

level B 

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 

Species/stock Population 

estimate 

Proposed 

level B takes 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 

1The 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 activityspecific and are designed to minimize 

acoustic exposures to marine mammal 

species. 

The take numbers NMFS proposes for 

authorization (Table 23) are considered 


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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

Species/stock Population 

estimate 

Proposed take authorization 

combined for all construction 

activities 

Total proposed 

takes 

(level A + 

level B) 

* Percentage 

of population 

or stock 

Proposed (%) 

level A takes 

Proposed 

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 

1Activities 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. 


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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, midfrequency 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

Species 

Level A 

harassment 

zone 

(m) (SEL) 

Level A 

harassment 

zone 

(m) (PK) 

Level B 

harassment 

zone 

(m) 

Pre-start 

clearance 

zone 

(m) 

Exclusion 

zone 

(m) 

Vessel 

separation 

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: 


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TABLE 24—PROPOSED CLEARANCE AND EXCLUSION ZONES 1 DURING SOUTH FORK WIND IMPACT PILE DRIVING WITH A

NOISE MITIGATION SYSTEM—Continued 

Species 

Level A 

harassment 

zone 

(m) (SEL) 

Level A 

harassment 

zone 

(m) (PK) 

Level B 

harassment 

zone 

(m) 

Pre-start 

clearance 

zone 

(m) 

Exclusion 

zone 

(m) 

Vessel 

separation 

distance 

(m) 

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. 

1Zones 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 redetection of the animal in the case of 

mysticetes, sperm whales, Risso’s 

dolphins and pilot whales, or 15 

minutes have elapsed without redetection 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 speciesspecific 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 


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

Species 

Level A 

harassment 

zone 

(m) (SEL) 

Level B 

harassment 

zone 

(m) (SPL) 

Pre-start 

clearance 

zone 

(m) 

Exclusion 

zone 

(m) 

Vessel 

separation 

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). 


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TABLE 26—PROPOSED MONITORING, CLEARANCE, AND EXCLUSION ZONES DURING HRG SURVEYS OPERATING CHIRP 

SUB-BOTTOM PROFILERS, BOOMERS, AND SPARKERS

Species 

Level A 

harassment 

zone 

(SEL) 

Level A 

harassment 

zone 

(PK) 

Maximum extent of zone in meters (m) from all potential HRG 

sound sources Vessel 

separation 

distance 

(m) 

Level B zones Pre-start 

clearance 

zone 

Exclusion 

zone CHIRPS Boomers and 

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. 


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


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8530 Federal Register / Vol. 86, No. 23 / Friday, February 5, 2021 / Notices 

• 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 constructionrelated 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. 


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

Æ Bearing and direction of travel and 

distance from pile driving activity, 

Æ changes in behavioral patterns, 

noting when/if they correspond to 

change in activity (e.g., turning source 

on or off), and 

Æ 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 inwater work window. The report would 

include marine mammal observations 

pre-activity, during-activity, and postactivity 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 


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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., populationlevel 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 


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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 longterm 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. 


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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-authorizationsunder-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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8536 Federal Register / Vol. 86, No. 23 / Friday, February 5, 2021 / Notices 

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 


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