Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Revolution Wind Offshore Wind Farm Project Offshore Rhode Island, 79072-79173 [2022-27491]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 87, Number 246 (Friday, December 23, 2022)]
[Proposed Rules]
[Pages 79072-79173]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-27491]



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Vol. 87

Friday,

No. 246

December 23, 2022

Part II





 Department of Commerce





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National Oceanic and Atmospheric Administration





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50 CFR Part 217





Takes of Marine Mammals Incidental to Specified Activities; Taking 
Marine Mammals Incidental to the Revolution Wind Offshore Wind Farm 
Project Offshore Rhode Island; Proposed Rule

Federal Register / Vol. 87 , No. 246 / Friday, December 23, 2022 / 
Proposed Rules

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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 217

[Docket No. 221214-0271]
RIN 0648-BL52


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to the Revolution Wind Offshore Wind 
Farm Project Offshore Rhode Island

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

ACTION: Proposed rule; proposed incidental take regulations; proposed 
letter of authorization; request for comments.

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SUMMARY: NMFS has received a request from Revolution Wind, LLC 
(Revolution Wind), a 50/50 joint venture between [Oslash]rsted North 
America, Inc. ([Oslash]rsted) and Eversource Investment, LLC, for 
Incidental Take Regulations (ITR) and an associated Letter of 
Authorization (LOA). The requested regulations would govern the 
authorization of take, by Level A harassment and/or Level B harassment, 
of small numbers of marine mammals over the course of 5 years (2023-
2028) incidental to construction of the Revolution Wind Offshore Wind 
Farm Project offshore of Rhode Island in a designated lease area on the 
Outer Continental Shelf (OCS-A-0486), within the Rhode Island-
Massachusetts Wind Energy Area (RI/MA WEA). Project activities likely 
to result in incidental take include pile driving (impact and 
vibratory), potential unexploded ordnance (UXO/MEC) detonation, and 
vessel-based site assessment surveys using high-resolution geophysical 
(HRG) equipment. NMFS requests comments on its proposed rule. NMFS will 
consider public comments prior to making any final decision on the 
promulgation of the requested ITR and issuance of the LOA; agency 
responses to public comments will be summarized in the final notice of 
our decision. The proposed regulations would be effective October 5, 
2023-October 4, 2028.

DATES: Comments and information must be received no later than January 
23, 2023.

ADDRESSES: Submit all electronic public comments via the Federal e-
Rulemaking Portal. Go to www.regulations.gov and enter NOAA-NMFS-2022-
0127 in the Search box. Click on the ``Comment'' icon, complete the 
required fields, and enter or attach your comments.
    Instructions: Comments sent by any other method, to any other 
address or individual, or received after the end of the comment period, 
may not be considered by NMFS. All comments received are a part of the 
public record and will generally be posted for public viewing on 
www.regulations.gov without change. All personal identifying 
information (e.g., name, address), confidential business information, 
or otherwise sensitive information submitted voluntarily by the sender 
will be publicly accessible. NMFS will accept anonymous comments (enter 
``N/A'' in the required fields if you wish to remain anonymous). 
Attachments to electronic comments will be accepted in Microsoft Word, 
Excel, or Adobe PDF file formats only.

FOR FURTHER INFORMATION CONTACT: Carter Esch, Office of Protected 
Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION:

Availability

    A copy of Revolution Wind's application and supporting documents, 
as well as a list of the references cited in this document, may be 
obtained online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable. In case of problems accessing these documents, 
please call the contact listed above (see FOR FURTHER INFORMATION 
CONTACT).

Purpose and Need for Regulatory Action

    This proposed rule would provide a framework under authority of the 
Marine Mammal Protection Act (MMPA) (16 U.S.C. 1361 et seq.) to allow 
for the authorization of take of marine mammals incidental to 
construction of the Revolution Wind Farm Project within the Bureau of 
Ocean Energy Management (BOEM) Renewable Energy lease area OCS-A 0486 
and along export cable corridors to landfall locations in Rhode Island. 
NMFS received a request from Revolution Wind for 5-year regulations and 
a Letter of Authorization (LOA) that would authorize take of 
individuals of four species of marine mammals by Level A harassment and 
Level B harassment and 12 species by only Level B harassment incidental 
to Revolution Wind's construction activities. No mortality or serious 
injury is anticipated or proposed for authorization. Please see the 
Legal Authority for the Proposed Action section below for definitions 
of harassment.

Legal Authority for the Proposed Action

    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, regulations are 
promulgated, and public notice and an opportunity for public comment 
are provided.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s) and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for taking for subsistence uses 
(where relevant). Further, NMFS must prescribe the permissible methods 
of taking and other ``means of effecting the least practicable adverse 
impact'' on the affected species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of the species or stocks for 
taking for certain subsistence uses (referred to as ``mitigation''); 
and requirements pertaining to the mitigation, monitoring and reporting 
of the takings are set forth. The definitions of all applicable MMPA 
statutory terms cited above are included below.
    Section 101(a)(5)(A) of the MMPA and the implementing regulations 
at 50 CFR part 216, subpart I, provide the legal basis for proposing 
and, if appropriate, issuing this rule containing 5-year regulations 
and associated LOA. This proposed rule also establishes required 
mitigation, monitoring, and reporting requirements for Revolution 
Wind's activities.

Summary of Major Provisions Within the Proposed Rule

    The major provisions of this proposed rule include:
     Establishing a seasonal moratorium on impact pile driving 
during the months of highest North Atlantic right whale (Eubalaena 
glacialis) presence in the project area (January 1-April 30);
     Establishing a seasonal moratorium on any unexploded 
ordnances or munitions and explosives of concern (UXOs/MECs) 
detonations during the months of highest North Atlantic right whale 
present in the project area (January 1-April 30).

[[Page 79073]]

     Requiring that any UXO/MEC detonations may only occur 
during hours of daylight and not during hours of darkness or nighttime.
     Conducting both visual and passive acoustic monitoring by 
trained, NOAA Fisheries-approved Protected Species Observers (PSOs) and 
Passive Acoustic Monitoring (PAM) operators before, during, and after 
the in-water construction activities;
     Requiring the use of sound attenuation device(s) during 
all impact pile driving and UXO/MEC detonations to reduce noise levels;
     Delaying the start of pile driving if a North Atlantic 
right whale is observed at any distance by the PSO on the pile driving 
or dedicated PSO vessels;
     Delaying the start of pile driving if other marine mammals 
are observed entering or within their respective clearance zones;
     Shutting down pile driving (if feasible) if a North 
Atlantic right whale is observed or if other marine mammals enter their 
respective shutdown zones;
     Implementing soft starts for impact pile driving and using 
the lowest hammer energy possible;
     Implementing ramp-up for high-resolution geophysical (HRG) 
site characterization survey equipment;
     Requiring PSOs to continue to monitor for 30 minutes after 
any impact pile driving occurs and for any and all UXO/MEC detonations;
     Increasing awareness of North Atlantic right whale 
presence through monitoring of the appropriate networks and VHF Channel 
16, as well as reporting any sightings to the sighting network;
     Implementing numerous vessel strike avoidance measures;
     A requirement to implement noise abatement system(s) 
during all impact pile driving and UXO/MEC detonations;
     Sound field verification requirements during impact pile 
driving and UXO/MEC detonation to measure in situ noise levels for 
comparison against the model results; and
     Removing gear from the water during fisheries monitoring 
research surveys if marine mammals are considered at-risk or are 
interacting with gear.
    Under Section 105(a)(1) of the MMPA, failure to comply with these 
requirements or any other requirements in a regulation or permit 
implementing the MMPA may result in civil monetary penalties. Pursuant 
to 50 CFR 216.106, violations may also result in suspension or 
withdrawal of the Letter of Authorization (LOA) for the project. 
Knowing violations may result in criminal penalties, under Section 
105(b) of the MMPA.

National Environmental Policy Act (NEPA)

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must evaluate the proposed action (i.e., promulgation of 
regulations and subsequent issuance of a 5-year LOA) and alternatives 
with respect to potential impacts on the human environment.
    Accordingly, NMFS proposes to adopt BOEM's Environmental Impact 
Statement (EIS), provided our independent evaluation of the document 
finds that it includes adequate information analyzing the effects of 
promulgating the proposed regulations and LOA issuance on the human 
environment. NMFS is a cooperating agency on BOEM's EIS. BOEM's draft 
EIS (Revolution Wind Draft Environmental Impact Statement (DEIS) for 
Commercial Wind Lease OCS-A 0486) was made available for public comment 
on September 2, 2022 (87 FR 54248), beginning the 45-day comment period 
ending on October 17, 2022. Additionally, BOEM held three in-person 
public hearings on October 4, 2022, in Aquinnah, MA, October 5, 2022, 
in East Greenwich, CT, and October 6, 2022, in New Bedford, MA, and two 
virtual public hearings on September 29 and October 11, 2022.
    Information contained within Revolution Wind's incidental take 
authorization (ITA) application and this Federal Register document 
collectively provide the environmental information related to these 
proposed regulations and associated 5-year LOA for public review and 
comment. NMFS will review all comments submitted in response to this 
document prior to concluding the NEPA process or making a final 
decision on the requested 5-year ITA and LOA.

Fixing America's Surface Transportation Act (FAST-41)

    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. 
FAST-41 also places a 2-year limitations period on any judicial claim 
that challenges the validity of a Federal agency decision to issue or 
deny an authorization for a FAST-41 covered project. 42 U.S.C. 4370m-
6(a)(1)(A).
    Revolution Wind's proposed project is listed on the Permitting 
Dashboard, where milestones and schedules related to the environmental 
review and permitting for the project can be found: https://www.permits.performance.gov/permitting-projects/revolution-wind-farm-project.

Summary of Request

    On October 8, 2021, Revolution Wind submitted a request for the 
promulgation of regulations and issuance of an associated 5-year LOA to 
take marine mammals incidental to construction activities associated 
with implementation of the Revolution Wind Offshore Wind Farm Project 
(herein ``the Project'') offshore of Rhode Island, in the BOEM lease 
area OCS-A-0486.
    Revolution Wind's request is for the incidental, but not 
intentional, taking of a small number of 16 marine mammal species 
(comprising 16 stocks) by Level A harassment (for four species or 
stocks) and Level B harassment (for all 16 species or stocks). Neither 
Revolution Wind nor NMFS expects serious injury or mortality to result 
from the specified activities based on the implementation of various 
mitigation measures as described below in the Proposed Mitigation 
section.
    In response to our questions and comments, and following extensive 
information exchange between Revolution Wind and NMFS, we received 
subsequent revised applications and/or supplementary materials on 
January 24, 2022, and February 11, 2022. Revolution Wind submitted a 
final version of the application on February 23, 2022, which NMFS 
deemed adequate and complete on February 28, 2022. This final 
application is available on NMFS' website at: https://www.fisheries.noaa.gov/action/incidental-take-authorization-revolution-wind-llc-construction-revolution-wind-energy.
    On March 21, 2022, a notice of receipt (NOR) of the application was 
published in the Federal Register (87 FR 15942), requesting comments 
and soliciting information related to Revolution Wind's request during 
a 30-day public comment period. During the NOR public comment period, 
NMFS received 27 substantive comments from two environmental non-
governmental organizations (ENGO) Oceana and the Rhode Island Saltwater 
Anglers Association (RISSA). NMFS has reviewed all submitted material 
and has taken these into consideration during the drafting of this 
proposed

[[Page 79074]]

rulemaking. Subsequently, in June 2022, new scientific information was 
released regarding marine mammal densities (Robert and Halpin, 2022) 
and, as such, Revolution Wind submitted an Updated Density and Take 
Estimation Memo in August that included updated marine mammal densities 
and take estimates. NMFS posted this memo on the NMFS website on August 
26, 2022.
    NMFS previously issued four Incidental Harassment Authorizations 
(IHAs) to [Oslash]rsted for the taking of marine mammals incidental to 
marine site characterization surveys (using HRG equipment) of the 
Revolution Wind's BOEM lease area (OCS-A 0486) and surrounding BOEM 
lease areas (OCS-A 0487, OCS-A 0500) (see 84 FR 52464, October 2, 2019; 
85 FR 63508, October 8 14, 2020; 87 FR 756, January 6, 2022; and 87 FR 
61575, October 12, 2022). To date, [Oslash]rsted has complied with all 
IHA requirements (e.g., mitigation, monitoring, and reporting). 
Information regarding [Oslash]rsted's monitoring results may be found 
in the Estimated Take section, and the full monitoring reports can be 
found on NMFS' website: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable.
    On August 1, 2022, NMFS announced proposed changes to the existing 
North Atlantic right whale vessel speed regulations to further reduce 
the likelihood of mortalities and serious injuries to endangered right 
whales from vessel collisions, which are a leading cause of the 
species' decline and a primary factor in an ongoing Unusual Mortality 
Event (87 FR 46921). Should a final vessel speed rule be issued and 
become effective during the effective period of this ITA (or any other 
MMPA incidental take authorization), the authorization holder would be 
required to comply with any and all applicable requirements contained 
within the final rule. Specifically, where measures in any final vessel 
speed rule are more protective or restrictive than those in this or any 
other MMPA authorization, authorization holders would be required to 
comply with the requirements of the rule. Alternatively, where measures 
in this or any other MMPA authorization are more restrictive or 
protective than those in any final vessel speed rule, the measures in 
the MMPA authorization would remain in place. The responsibility to 
comply with the applicable requirements of any vessel speed rule would 
become effective immediately upon the effective date of any final 
vessel speed rule and, when notice is published of the effective date, 
NMFS would also notify Revolution Wind if the measures in the speed 
rule were to supersede any of the measures in the MMPA authorization 
such that they were no longer required.

Description of the Specified Activity

Overview

    Revolution Wind has proposed to construct and operate a 704 
megawatt (MW) wind energy facility (known as Revolution Wind) in State 
and Federal waters in the Atlantic Ocean in lease area OCS-A-0486, 
which would provide power to Rhode Island and Connecticut. Revolution 
Wind's project would consist of several different types of permanent 
offshore infrastructure, including wind turbine generators (WTGs; e.g., 
Siemens Gamesa 11 megawatt (MW)) and associated foundations, offshore 
substations (OSS), offshore substation array cables, and substation 
interconnector cables. In their application, Revolution Wind indicated 
they plan to install up to 100 WTGs and two offshore substations (OSS) 
via impact pile driving; the temporary installation and removal of two 
cofferdams to assist in the installation of the export cable route by 
vibratory pile driving; several types of fishery and ecological 
monitoring surveys; the placement of scour protection; trenching, 
laying, and burial activities associated with the installation of the 
export cable route from OSSs to shore-based converter stations and 
inter-array cables between turbines; HRG vessel-based site 
characterization surveys using active acoustic sources with frequencies 
of less than 180 kilohertz (kHz); and the potential detonation of up to 
13 UXO/MECs of different charge weights, as necessary. Vessels would 
transit within the project area, and between ports and the wind farm to 
transport crew, supplies, and materials to support pile installation. 
All offshore cables would connect to onshore export cables, 
substations, and grid connections, which would be located at Quonset 
Point in North Kingstown, Rhode Island.
    Since submission of the application, Revolution Wind has re-
evaluated previous survey data and analyzed additional survey data. On 
October 13, 2022, Revolution Wind informed NMFS that 21 of the 100 WTG 
positions are not able to be developed due to installation 
infeasibility. On November 8, 2022, Revolution Wind provided NMFS with 
a Reduced WTG Foundation Scenario memo that includes revised exposure 
and take estimates based on the installation of 79 WTG foundations; 
therefore, for purposes of this proposed rule, we are analyzing take 
requests associated with the installation of the reduced number of 
foundations (i.e., 79 WTG foundations plus two OSS foundations, for a 
total of 81 foundations). In addition, the amount of trackline within 
the lease area that would be surveyed using HRG equipment has been 
reduced to reflect the shorter overall distance of inter-array cables 
that would be required for 79 rather than 100 WTG foundations. 
Revolution Wind now estimates that they would survey 9,559 km over 
136.6 days rather than 11,600 km over 165.7 days during construction 
(Year 1) in the lease area. Following construction (i.e., in Years 2-
5), Revolution Wind now plans to survey 2,117 km over 30.2 days per 
year rather than 2,640 km over 37.7 days per year in the lease area. 
The amount of survey work that would be conducted in the export cable 
corridor would not change from what was included in the ITR 
application, despite installation of fewer WTG foundations. Marine 
mammals exposed to elevated noise levels during impact and vibratory 
pile driving, potential detonations of UXOs, or site characterization 
surveys, may be taken, by Level A harassment and/or Level B harassment, 
depending on the specified activity.

Dates and Duration

    Revolution Wind anticipates that activities with the potential to 
result in harassment of marine mammals would occur throughout all five 
years of the proposed regulations which, if promulgated, would be 
effective from October 5, 2023, through October 4, 2028. Installation 
of monopile foundations, cable landfall construction, and UXO/MEC 
detonations in the Revolution Wind Farm (RWF) and Revolution Wind 
Export Cable (RWEC) corridor would occur over approximately 12 to 18 
months, from the third quarter (Q3) of 2023 to the fourth quarter (Q4) 
of 2024 (Figure 1). Through the end of the 5-year effective period of 
the requested regulations in Q3 2028, HRG surveys could take place 
within the RWF and RWEC at any time of year; the timeframe for these 
post-construction surveys is not included in Figure 1. The general 
construction schedule in Figure 1 and Table 1 presents all of the major 
project components, including those that may result in take, and those 
from which incidental take is not expected (i.e., components in italics 
in Figure 1 and Table 1).

[[Page 79075]]

[GRAPHIC] [TIFF OMITTED] TP23DE22.000


                       Table 1--Revolution Wind's Construction and Operations Schedule \1\
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          Project area               Project component                  Expected duration and timing
----------------------------------------------------------------------------------------------------------------
RWF Construction...............  WTG foundation            ~5 months Q2-Q3 2024.
                                  installation.
                                 OSS foundation            ~2-3 days Q2-Q3 2024.
                                  installation.
                                 Array cable installation  ~5 months Q1-Q3 2024.
                                 HRG surveys.............  Any time of year Q3 2023-Q4 2024.
                                 In situ UXO/MEC disposal  ~ up to 7 days Q3-Q4 2023.
RWEC Construction..............  Cable landfall            ~ up to 56 days Q3-Q4 2023.
                                  installation (temporary
                                  cofferdam or casing
                                  pipe installation and
                                  removal.
                                 Offshore export cable     ~8 months Q4 2023-Q4 2024.
                                  installation.
                                 HRG surveys.............  Any time of year Q3 2023-Q4 2024.
                                 In situ UXO/MEC disposal  ~ up to 6 days Q3-Q4 2023.
Operations.....................  HRG surveys.............  Any time of year Q4 2024-Q3 2028.
----------------------------------------------------------------------------------------------------------------
\1\ Project components in italics are not expected to result in take.

WTG and OSS Pile Installation (Impact Pile Driving)
    The installation of 79 WTG and 2 OSS monopiles foundations would be 
limited to May through December, given the seasonal restriction on 
impact pile driving in the RWF from January 1-April 30. As described 
previously, Revolution Wind intends to install all monopile foundations 
in a single year. However, it is possible that monopile installation 
would continue into a second year, depending on construction logistics 
and local and environmental conditions that may influence Revolution 
Wind's ability to maintain the planned construction schedule.
    Installation of a single WTG monopile foundation is expected to 
require a maximum of 4 hours of active impact hammering, which can 
occur either in a continuous 4-hour interval or intermittently over a 
longer time period. For the purposes of acoustic modeling, it was 
assumed that installation of a single WTG monopile would require a 
total of 10,740 hammer strikes over 220 minutes (3.7 hours). Revolution 
Wind assumes that a maximum of three WTG monopile foundations can be 
driven into the seabed per day, although fewer installations per day 
may occur depending on logistics and environmental conditions. 
Installation of each of the two OSS monopile foundations is expected to 
require a larger number of hammer strikes (11,564) over a longer period 
(380 minutes, or 6.3 hours), given that the OSS monopile foundation is 
larger in diameter than the WTG monopile foundation. Revolution Wind 
has requested 24-hour pile driving, which would consist of intermittent 
impact pile driving that could occur anytime within a 24-hour 
timeframe, amounting to a maximum of 12 hours of active pile driving 
per day to install up to three monopiles. No concurrent impact pile 
driving (i.e., installing multiple piles at the same time) is planned 
for this project.
    Revolution Wind anticipates that the first WTG would become 
operational in Q2 of 2024, after installation is completed and all 
necessary components, such as array cables, OSSs, export cable routes, 
and onshore substations are installed. Turbines would be commissioned 
individually by personnel on location, so the number of commissioning 
teams would dictate how quickly the process would be achieved. 
Revolution Wind expects that all turbines would be commissioned by Q4 
2024.
Potential UXO/MEC Detonations
    Revolution Wind anticipates encountering the potential presence of 
UXOs/MECs in and around the project area during the 5 years of the 
proposed rule. These UXOs/MECs are defined as explosive munitions 
(e.g., shells, mines, bombs, torpedoes, etc.) that did not explode or 
detonate when they were originally deployed or that were intentionally 
discarded to avoid detonations on land. Typically, these munitions 
could be left behind following Navy military training, testing, or 
operations. Revolution Wind primarily plans for avoidance or

[[Page 79076]]

relocation of any UXOs/MECs found within the project area, when 
possible. In some cases, it may also be possible that the UXO/MEC could 
be cut up to extract the explosive components. However, Revolution Wind 
notes this may not be possible in all cases and in situ disposal may be 
required. If in situ disposal is required, all disposals would be 
performed using low-order methods (deflagration), which are considered 
less impactful to marine mammals, first and then would be elevated up 
to high-order removal (detonation), if this approach is determined to 
be necessary. In the event that high-order removal is needed, all 
detonations would only occur during daylight hours.
    Based on preliminary survey data, Revolution Wind conservatively 
estimates a maximum of 13 days on which UXO/MEC detonation may occur, 
with up to one UXO/MEC being detonated per day and a maximum of 13 
UXOs/MECs being detonated over the entire 5-year period. NMFS notes 
that UXOs/MECs may be detonated from May through November in any year; 
however, no UXOs/MECs would be detonated in Federal waters between 
December 1 and April 30 of any year during the effective period of the 
proposed rule.
Cable Landfall Construction
    Cable landfall construction is one of the first activities 
scheduled to occur, sometime within the Q3 2023 to Q4 2023 timeframe. 
Installation of the RWEC landfall would be accomplished using a 
horizontal directional drilling (HDD) methodology. The drilling 
equipment would be located onshore and used to create a borehole, one 
for each cable, from shore to an exit point on the seafloor 
approximately 250 m (800 ft) offshore. At the seaward exit site for 
each borehole, construction activities may include a casing pipe 
scenario, which involves the temporary installation of two casing 
pipes, each supported by sheet pile goal posts, to collect drilling mud 
from the borehole exit point. Alternatively, two temporary cofferdams 
may be installed to create a dry environment from which drilling mud 
could be collected. Each cofferdam, if required, may be installed as 
either a sheet-piled structure into the seafloor or a gravity cell 
cofferdam placed on the seafloor using ballast weight. Only one of 
these three landfall construction alternatives (i.e., casing pipe 
scenario, sheet pile cofferdam, or gravity cell cofferdam) would be 
installed.

Casing Pipe Installation and Removal

    The casing pipes would each require up to 3 hours per day of 
pneumatic impact hammering to install, over a period of two days for 
each pipe (6 hours total over 4 days for both), depending on the number 
of pauses required to weld additional sections onto the casing pipe. 
Removal of the casing pipe would also involve the use of a pneumatic 
pipe ramming tool, but the pipe would be pulled out of the seabed while 
hammering was occurring instead of being pushed into it. The same total 
of 4 days of pneumatic hammering (6 hours total), may be required for 
removal of both pipes.
    Up to six goal posts may be installed to support each casing pipe 
(12 goal posts total), which would be located between a barge and the 
penetration point on the seabed. Each goal post would be composed of 
two vertical sheet piles installed using a vibratory hammer such as an 
American Piledriving Equipment (APE) model 300 (or similar). A 
horizontal cross beam connecting the two sheet piles would then be 
installed to provide support to the casing pipe. For each casing pipe, 
installation of six goal posts would require up to three days total of 
vibratory pile driving, or up to 6 days total for both casing pipes. 
Removal of the goal posts would also involve the use of a vibratory 
hammer and would likely require approximately the same amount of time 
as installation (6 days total for both casing pipes). Thus, use of a 
vibratory pile driver to install and remove the 12 goal posts may occur 
on up to 12 days at the landfall location.

Cofferdam Installation and Removal

    If Revolution Wind selects this alternative, installation of two 50 
m x 10 m x 3 m (164 ft x 33 ft x 10 ft) sheet pile cofferdams at the 
cable landfall construction location near Quonset Point in Kingstown, 
Rhode Island, may require up to 14 days of vibratory pile driving per 
cofferdam (28 days total). After the sheet piles are installed, the 
inside of each cofferdam would be excavated to approximately 10 ft (3 
m). Once HDD operations are complete and the cables installed, the 
cofferdams would be removed, using vibratory hammering, over the course 
of up to 14 days per cofferdam. Separate cofferdams would be installed 
and removed for each of the two export cable bundles, amounting to up 
to 56 days of vibratory hammering at the landfall location.
    If Revolution Wind decides to install the gravity cell cofferdam 
(which would have the same approximate dimensions as the sheet pile 
cofferdam), the structure would be fabricated onshore, transported to 
the site on a barge, and then lifted off the barge and placed on the 
seafloor using a crane. This process would not involve pile driving or 
other underwater sound producing activities, and is not expected to 
result in harassment of marine mammals.
    Revolution Wind anticipates that impacts from cofferdam 
installation and removal using sheet piles would exceed any potential 
impacts for the use of alternative methods (i.e., gravity cell 
cofferdam, casing pipe scenario), and therefore the cofferdam estimates 
using the sheet pile approach ensures that the most conservative values 
are carried forward in analyses for this proposed action.
HRG Surveys
    High-resolution geophysical site characterization surveys would 
occur annually throughout the 5 years the rule and LOA would be 
effective. The specific duration would be dependent on the activities 
occurring in that year (i.e., construction versus non-construction 
year). HRG surveys would utilize up to a maximum of four vessels 
working concurrently in different sections of the lease area and RWEC 
corridor. During the first year of construction (when the majority of 
foundations and cables would be installed), Revolution Wind estimates 
that 9,669 km would be surveyed over 136.6 days in the lease area, and 
5,748 km would be surveyed along the RWEC corridor over 82.1 days, in 
water depths ranging from 2 m (6.5 ft) to 50 m (164 ft). During non-
construction years (the final 4 years in which the regulations and LOA 
would be effective), Revolution Wind estimates 2,117 km would be 
surveyed in the lease area over 30.2 days and 1,642 km would be 
surveyed over 23.5 days along the RWEC corridor each year. Revolution 
Wind anticipates that each vessel would survey an average of 70 km (44 
miles) per day, assuming a 4 km/hour (2.16 knots) vessel speed and 24-
hour operations. Each day that a survey vessel covers 70 km (44 miles) 
of survey trackline is considered a vessel day. For example, Revolution 
Wind would consider 2 vessels operating concurrently, with each 
surveying 70 km (44 miles), two vessel days. In some cases, vessels may 
conduct daylight-only 12-hour nearshore surveys, covering half that 
distance (35 km or 22 miles). Over the course of 5 years, HRG surveys 
would be conducted at any time of year for a total of 30,343 km (18,854 
miles) over 433.5 vessel days. In this schedule, Revolution Wind 
accounted for periods of down-time due to

[[Page 79077]]

inclement weather or technical malfunctions.

Specific Geographic Region

    Revolution Wind would install the RWF in Federal waters within the 
designated lease area OCS-A 0486 (Figure 2). The 339 square kilometer 
(km\2\) (83,798 acres) lease area is located within the 1,036 km\2\ 
(256,000 acres) RI/MA WEA. The edge of the lease area closest to land 
is approximately 15 mi (13 nm, 24 km) southeast of the Rhode Island 
coast. The RWEC corridor would traverse both federal waters and state 
territorial waters of Rhode Island, extending up to approximately 50 mi 
(80 km) from the RWF to the RWEC landfall location at Quonset Point in 
North Kingstown, Rhode Island. Two temporary cofferdams or casing pipes 
(with associated goal posts) would be installed at Quonset Point to 
facilitate the sea-to-shore transition for the export cables. Water 
depths in the lease area range from 24 to 50 m (78.7 to 164.0 ft), 
averaging 35 m (114.8 ft), while water depths along the RWEC corridor 
range from 10 to 45 m (32.8 to 147.6 ft). The cable landfall 
construction area would be approximately 15 m (49.2 ft) in depth.
    Revolution Wind's specified activities would occur in the Northeast 
U.S. Continental Shelf Large Marine Ecosystem (NES LME), an area of 
approximately 260,000 km\2\ from Cape Hatteras in the south to the Gulf 
of Maine in the north. Specifically, the lease area and cable corridor 
are located within the Mid-Atlantic Bight subarea of the NE LME which 
extends between Cape Hatteras, North Carolina, and Martha's Vineyard, 
Massachusetts, extending eastward into the Atlantic to the 100-m 
isobath. In the Middle Atlantic Bight, the pattern of sediment 
distribution is relatively simple. The continental shelf south of New 
England is broad and flat, dominated by fine grained sediments. Most of 
the surficial sediments on the continental shelf are sands and gravel. 
Silts and clays predominate at and beyond the shelf edge, with most of 
the slope being 70-100 percent mud. Fine sediments are also common in 
the shelf valleys leading to the submarine canyons, as well as in areas 
such as the ``Mud Patch'' south of Rhode Island. There are some larger 
materials, including boulders and rocks, left on the seabed by 
retreating glaciers, along the coast of Long Island and to the north 
and east, including in Rhode Island Sound near where the Revolution 
Wind lease area is located.
    In support of the Rhode Island Ocean Special Area Management Plan 
development process, Codiga and Ullman (2011) reviewed and summarized 
the physical oceanography of coastal waters off Rhode Island. 
Conditions off the coast of Rhode Island are shaped by a complex 
interplay among wind-driven variability, tidal processes, and density 
gradients that arise from combined effects of interaction with adjacent 
estuaries, solar heating, and heat flux through the air-sea interface. 
In winter and fall, the stratification is minimal and circulation is a 
weak upwelling pattern, directed offshore at shallow depths and onshore 
near the seafloor; in spring and summer, strong stratification develops 
due to an important temperature contribution, and a system of more 
distinct currents occurs. These include the southern New England shelf 
flow westward along the offshore area, which bifurcates in the east 
where a portion moves northward as the RIS Current, a narrow flow that 
proceeds counterclockwise around the perimeter of RIS, likely in 
association with a tidal mixing front.
    The Revolution Wind lease area, located on Cox Ledge, is dominated 
by complex habitats that support diverse assemblages of fish and 
invertebrates. Large contiguous areas of complex habitats are located 
centrally and throughout the entire southern portion of the lease area. 
Smaller, patchy areas of complex habitats also occur throughout the 
northern portion of the lease area. Biogeographic patterns in Rhode 
Island Sound are persistent from year to year, yet variable by season, 
reflected by the cross-shelf migration of fish and invertebrate species 
in the spring and fall (Malek et al., 2014).
BILLING CODE 3510-22-P

[[Page 79078]]

[GRAPHIC] [TIFF OMITTED] TP23DE22.001

BILLING CODE 3510-22-C

Detailed Description of Specific Activity

    Below, we provide detailed descriptions of Revolution Wind's 
activities, explicitly noting those that are anticipated to result in 
the take of marine mammals and for which incidental take authorization 
is requested. Additionally, a brief explanation is provided for those 
activities that are not expected to result in the take of marine 
mammals.
Installation of WTG and OSS Monopile Foundations
    Revolution Wind plans to install 81 monopile foundations over 
approximately one year within the 5-year effective period of the 
proposed rule. To do so, they would use impact pile driving, which is 
expected to result

[[Page 79079]]

in the incidental take of marine mammals. Pile driving would be limited 
to the months of May through December, annually, and would primarily 
occur in Year 1 (and potentially Year 2, should significant schedule 
delays occur). Monopiles are the only foundation type proposed for the 
project. As mentioned previously, the 81 monopiles installed to support 
the 79 WTG and two OSSs would have a maximum diameter of 12 m (39.4 ft) 
and 15 m (49.2 ft), respectively, and would be driven to a maximum 
penetration depth of 50 m (164 ft) using an IHC-4000 kilojoules (kJ) 
impact hammer. The monopiles are tapered such that the top diameter is 
7 m (for both WTG and OSS foundations), the bottom diameter is 12-m 
(WTG) or 15-m (OSS), with both sizes tapering near the water line 
(referred to as 7/12-m and 7/15-m monopiles herein).
    A monopile foundation typically consists of a single steel tubular 
section, with several sections of rolled steel plate welded together. 
Schematic diagrams showing potential heights and dimensions of the 
various components of a monopile foundation are shown in Figures 3 and 
4 of Revolution Wind's ITA application.
    A typical monopile installation sequence begins with the monopiles 
being transported directly to the lease area for installation, or to 
the construction staging port by an installation vessel or a feeding 
barge. At the foundation installation location, the main installation 
vessel (heavy lift, or jack-up vessel) upends the monopile in a 
vertical position in the pile gripper mounted on the side of the 
vessel. 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. Once the monopile is lowered to the seabed, 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 hydraulic impact 
hammer is then lifted on top of the pile to commence pile driving with 
a soft start (see Proposed Mitigation section). The largest impact 
hammer Revolution Wind expects to use for driving monopiles produces up 
to 4,000 kJ of energy, however, the required energy to install a 
monopile may ultimately be far less than 4,000 kJ. The intensity (i.e., 
hammer energy level) of impact hammering would be gradually increased 
based on resistance from the sediments (see Estimated Take for the 
potential hammer schedule and strike rate).
    Pile installation would occur during daylight hours and could 
continue into nighttime hours if pile installation is started 1.5 hours 
prior to civil sunset. Alternatively, if Revolution Wind submits an 
Alternative Monitoring Plan (as part of the Pile Driving and Marine 
Mammal Monitoring Plan) that reliably demonstrates to NMFS that 
Revolution Wind can effectively visually and acoustically monitor 
marine mammals during nighttime hours, they may initiate pile driving 
during night (see Proposed Mitigation section). If NMFS approves 
Revolution Wind's plan and allows pile driving to occur at night, 
Revolution Wind plans to install three monopiles per day although, 
given logistical constraints (e.g., sea state limitations for impact 
pile driving, weather) and the coordination required, it is possible 
that fewer than three monopiles would be installed per day.
    It is estimated that a single foundation installation sequence 
would require up to approximately nine hours (one hour pre-start 
clearance, up to four hours of pile driving, and four hours to move to 
the next location). Again, no concurrent impact pile driving would 
occur, regardless of the number of piles installed per day. Once 
construction begins, Revolution Wind would proceed as rapidly as 
possible, while meeting all required mitigation and monitoring 
measures, to reduce the total duration of construction such that work 
is condensed into summer months when right whale occurrence is expected 
to be lowest in the project area.
UXO/MEC Detonations
    Revolution Wind anticipates the potential for construction 
activities to encounter UXO/MECs on the seabed within the RWF and along 
the RWEC corridor. The risk of incidental detonation associated with 
conducting seabed-altering activities such as cable laying and 
foundation installation in proximity to UXO/MECs jeopardizes the health 
and safety of project participants (Revolution Wind 2022). Revolution 
Wind follows an industry standard As Low as Reasonably Practicable 
(ALARP) process that minimizes the number of potential detonations 
(Construction and Operations Plan (COP) Appendix G; Revolution-Wind 
2022). For UXO/MECs that are positively identified on the seabed in 
proximity to planned activities, several alternative strategies would 
be considered prior to in-situ UXO/MEC disposal. These may include (1) 
relocating the activity away from the UXO/MEC (avoidance), (2) moving 
the UXO/MEC away from the activity (lift and shift), (3) cutting the 
UXO/MEC open to apportion large ammunition or deactivate fused 
munitions, using shaped charges to reduce the net explosive yield of a 
UXO/MEC (low-order detonation), or (4) using shaped charges to ignite 
the explosive materials and allow them to burn at a slow rate rather 
than detonate instantaneously (deflagration) (Revolution Wind 2022). 
Only after these alternatives are considered would in-situ high-order 
UXO/MEC detonation be pursued. To detonate a UXO/MEC, a small charge 
would be placed on the UXO/MEC and ignited, causing the UXO/MEC to then 
detonate, which could result in the taking of marine mammals.
    To better assess the potential UXO/MEC encounter risk, HRG surveys 
have been and continue to be conducted to identify potential UXO/MECs 
that have not been previously mapped. As these surveys and analysis of 
data from them are still underway, the exact number and type of UXO/
MECs in the project area are not yet known. As a conservative approach 
for the purposes of the impact analysis, Revolution Wind assumed that 
up to 13 UXO/MEC 454-kg (1,000 pounds; lbs) charges (up to seven UXO/
MECs in the RWF and up to six UXO/MECs along the RWEC corridor), which 
is the largest charge that is reasonably expected to be encountered, 
may require in situ detonation. Although it is highly unlikely that all 
13 charges would weigh 454 kg, this approach was determined to be the 
most conservative for the purposes of impact analysis. If necessary, 
these detonations would occur on up to 13 different days (i.e., only 
one detonation would occur per day). In the event that high-order 
removal (detonation) is determined to be the preferred and safest 
method of disposal, all detonations would occur during daylight hours. 
UXO/MEC detonations would be prohibited from December 1 through April 
30 to provide protection for right whales during the timeframe they are 
expected to occur more frequently in the project area.
Export Cable Landfall Construction
    Once construction plans are completed, Revolution Wind would 
determine whether to install gravity cell cofferdam, sheet pile 
cofferdams, or the casing pipe scenario. Again, only installation of 
the latter two alternatives are expected to result in the take of 
marine mammals. As mentioned previously, the amount of take incidental 
to installation of the casing

[[Page 79080]]

pipe alternative is expected to be less than or equal to, and occur 
over a much shorter duration than, that from installation of sheet pile 
cofferdams. Installation of sheet pile cofferdams (described below) was 
carried forward in the take estimation analyses, given the large size 
of the Level B harassment zone and the longer duration of the activity 
(see Estimated Take section). Compared to the sheet pile cofferdam 
alternative, installation of the casing pipe, described below, produced 
larger Level A harassment (SELcum) zones due to the high 
hammering rate required for the relatively small hammer to install the 
pipe. The potential for Level A harassment incidental to casing pipe 
installation is higher than it is for cofferdam installation, assuming 
a marine mammal remains within the relevant Level A harassment zone for 
the duration of the installation. However, the short duration of 
required pneumatic hammering (see below) coupled with implementation of 
Revolution Wind's proposed mitigation and monitoring measures (i.e., 
shutdown zones equivalent to the size of the casing pipe Level A 
harassment zones) would decrease the likelihood of Level A harassment 
to the extent that neither Revolution Wind nor NMFS anticipates it 
would occur, nor is it proposed for authorization.

Installation and Removal of Casing Pipes

    Installation of two casing pipes would be completed using pneumatic 
pipe ramming equipment, while installation of sheet piles for goal 
posts would be completed using a vibratory pile driving hammer 
(previously described). Casing pipe and sheet pile installations would 
not occur simultaneously, and would be limited to daylight hours.
    The casing pipe would be installed at a slight upward angle 
relative to the seabed so that the pipe creates a straight alignment 
between the point of penetration at the seabed and the construction 
barge. Casing pipe installation would occur from the construction barge 
and be accomplished using a pneumatic pipe ramming tool (Gundoram 
Taurus or similar) with a hammer energy of up to 18 kJ. If necessary, 
additional sections of casing pipe may be welded together on the barge 
to extend the length of the casing pipe from the barge to the 
penetration depth in the seabed. As mentioned previously, installation 
of each casing pipe would require up to 3 hours per day of pneumatic 
hammering for 2 days, for a total of 6 hours per pipe. Removal of each 
casing pipe may require use of the pneumatic hammering tool (during 
which the pipe is pulled from the seabed) for the same amount of time 
as installation (3 hours of pneumatic hammering for 2 days for each 
casing pipe; total of 6 hours per pipe).
    Up to six goal posts would be installed for each casing pipe, for a 
total of twelve goal posts. As described previously, each goal post 
would be composed of 2 vertical sheet piles installed using a vibratory 
hammer with a horizontal cross beam connecting the two sheet piles. Up 
to 10 additional sheet piles may be installed per casing pipe to help 
anchor the barge and support the construction activities. This results 
in a total of up to 22 sheet piles per casing pipe, for a total of 44 
sheet piles to support both casing pipes. Sheet piles used for the goal 
posts and supports would be up to 30 m (100 ft) long, 0.6 m (2 ft) 
wide, and 1 inch thick. Installation of the goal posts would require up 
to 3 days per casing pipe, or up to 6 days total for both casing pipes. 
Removal of the goal posts would also involve the use of a vibratory 
hammer and likely require approximately the same amount of time as 
installation (6 days total for both casing pipes). Thus, use of a 
vibratory pile driver to install and remove sheet piles may occur on up 
to 12 days at the landfall location. All of the sheet pile goal posts 
would be installed first, followed by installation of the casing pipe.

Installation and Removal of Temporary Cofferdams

    As an alternative to the casing pipe/goal post scenario described 
above, two cofferdams may be installed to allow for a dry environment 
during construction and manage sediment, contaminated soil, and 
bentonite (drilling mud used during HDD operations). If required, the 
cofferdams may be installed as either a sheet-piled structure (driven 
into the sea floor) or a gravity cell cofferdam placed on the seafloor 
using ballast weight. Regardless of the type of structure, the 
cofferdams could each measure up to 50 m x 10 m x 3 m (164 ft x 33 ft x 
10 ft). If a gravity cell cofferdam was selected for installation, the 
structure would be fabricated onshore, transported to the site on a 
barge, and then lifted off the barge and placed on the seafloor using a 
crane. This process would not involve pile driving or other underwater 
sound producing activities so is not carried forward into take 
analyses. Given that the design process for the HDD is still ongoing, 
Revolution Wind is not able to commit to a particular landfall 
construction scenario. As the design matures, Revolution Wind would 
refine the appropriate HDD export cable landfall methodology based on 
site conditions and state permit requirements.
    If cofferdams are installed using sheet piles, a vibratory hammer 
such as an APE model 200T (or similar) would be used to drive sheet 
piles of up to 30 m (100 ft) long, 0.6 m (2 ft) wide, and 1 inch thick. 
The sidewalls and endwall would be driven to a depth of up to 30 ft 
(9.1 m); sections of the shore-side endwall would be driven to a depth 
of up to 6 ft (1.8 m) to facilitate the borehole entering underneath 
the endwall. Installation of each sheet pile cofferdam may take up to 
14 days, as would removal, for a total of 28 days per cofferdam or 56 
days of vibratory hammer use (installation and removal) for both 
cofferdams.
HRG Surveys
    HRG surveys would be conducted to identify any seabed debris, and 
to support micro-siting of the WTG and OSP foundations and cable 
routes. These surveys may utilize active acoustic equipment such as 
multibeam echosounders, side scan sonars, shallow penetration sub-
bottom profilers (SBPs) (e.g., Compressed High-Intensity Radiated 
Pulses (CHIRPs) non-parametric SBP), medium penetration sub-bottom 
profilers (e.g., sparkers and boomers), ultra-short baseline 
positioning equipment, and marine magnetometers, some of which are 
expected to result in the take of marine mammals. Surveys would occur 
annually, with durations dependent on the activities occurring in that 
year (i.e., construction year versus a non-construction year).
    As summarized previously, HRG surveys would be conducted using up 
to four vessels to survey the RWF and RWEC corridor 12-24 hours/day for 
a total of 345.8 vessel days, operating at any time of the year over 
the course of five years. On average, 70-line km would be surveyed per 
vessel each vessel day at approximately 4 km/hour (2.16 knots). Two 12-
hr surveys covering 35 km/per day each would count as one vessel day 
because one complete vessel day is defined by the total kilometers 
surveyed (i.e.,70 km). While the final survey plans would not be 
completed until construction contracting commences, approximately 50 
percent (218.7 days; 15,307 km (9,511 miles)) of the total survey 
effort would occur during the construction phase (2023-2024). During 
non-construction periods, an estimated 3,759 km (2,336 miles) would be 
surveyed over 53.7 days each year in the RWF and along the RWEC 
corridor. The purpose of surveying during construction years is to 
monitor

[[Page 79081]]

installation activities, provide third-party verification of 
contractor's work, and assess seabed levels pre-, during, and post-
seabed disturbing activities. The purpose of surveying during non-
construction years is to monitor seabed levels and scour protection, 
identify any risks to inter-array and export cable integrity, and 
conduct seabed clearance surveys prior to maintenance/repair.
    Of the HRG equipment types proposed for use, the following have the 
potential to result in take:
     Shallow penetration sub-bottom profilers (SBPs) 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.
    Table 2 identifies all the representative survey equipment that 
operates 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 HRG survey activities, and are likely to be 
detected by marine mammals given the source level, frequency, and 
beamwidth of the equipment. Equipment with operating frequencies above 
180 kHz (e.g., side-scan sonar (SSS), multibeam echosounder (MBES)) and 
equipment that does not have an acoustic output (e.g., magnetometer) 
would also be used, but are not discussed further because they are 
outside the general hearing range of marine mammals likely to occur in 
the project area. No harassment exposures can be reasonably expected 
from the operation of these sources; therefore, they are not considered 
further in this proposed action.

                                                 Table 2--Summary of Representative HRG Survey Equipment
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Source
                                                         Operating      level       Source       Pulse     Repetition   Beamwidth
         Equipment type           Representative model   frequency     SPLrms    level  0-pk   duration    rate  (Hz)   (degrees)    Information source
                                                           (kHz)        (dB)         (dB)        (ms)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sub-bottom Profiler............  EdgeTech 216.........         2-16        195             -          20            6           24  MAN
                                 EdgeTech 424.........         4-24        176             -         3.4            2           71  CF
                                 Edgetech 512.........       0.7-12        179             -           9            8           80  CF
                                 GeoPulse 5430A.......         2-17        196             -          50           10           55  MAN
                                 Teledyn Benthos CHIRP         2-17        197             -          60           15          100  MAN
                                  III--TTV 170.
Sparker........................  Applied Acoustics          0.3-1.2        203            21         1.1            4         Omni  CF
                                  Dura-Spark UHD (400                                      1
                                  tips, 500 J).
Boomer.........................  Applied Acoustics            0.1-5        205            21         0.6            4           80  CF
                                  triple plate S-Boom                                      1
                                  (700-1,000 J).
--------------------------------------------------------------------------------------------------------------------------------------------------------
- = not applicable; ET = EdgeTech; J = joule; kHz = kilohertz; dB = decibels; SL = source level; UHD = ultra-high definition; AA = Applied Acoustics;
  rms = root-mean square; [micro]Pa = microPascals; re = referenced to; SPL = sound pressure level; PK = zero-to-peak pressure level; Omni =
  omnidirectional source.
\a\ The Dura-spark measurements and specifications provided in Crocker and Fratantonio (2016) were used for all sparker systems proposed for the survey.
  These include variants of the Dura-spark sparker system and various configurations of the GeoMarine Geo-Source sparker system. 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.
\b\ 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.

Vessel Activity
    During construction and development of the project, associated 
vessels would slightly increase the volume of traffic in the project 
area, particularly during the first 12-18 months throughout 
construction of the RWF and installation of the RWEC. The largest size 
vessels are expected during the monopile installation phase, with 
floating/jack-up crane barges, DP-equipped cable laying vessels, and 
associated tugs and barges transporting construction equipment and 
materials. Up to 60 vessels may be utilized for construction across 
various components of the Project including installation of the 
foundations, WTGs, OSSs, inter-array cables, and OSS-Link Cable 
(Revolution Wind COP Table 3.3-26; Revolution-Wind 2022). The types of 
vessels Revolution Wind anticipates using during construction 
activities and operations, as well as the anticipated number of vessels 
and vessel trips, are summarized in Tables 3 and 4. The actual number 
of vessels involved in the Project at one time is highly dependent on 
the final schedule, the final impacts of boulder clearance and in situ 
UXO/MEC disposal, 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 U.S (Revolution Wind, 2022).
    During construction, the Project would involve the use of temporary 
construction areas and construction ports. Revolution Wind is 
considering multiple port locations and any combination of the ports 
under consideration may be utilized. The ports that may be used during 
construction are as follows:
     Construction Hub: Port of Montauk (New York), Port 
Jefferson (New York), Port of Brooklyn (New York), Port of Davisville 
and Quonset Point (Rhode Island), and/or Port of Galilee (Rhode 
Island).
     Foundation Marshaling and Advanced Foundation Component 
Fabrication: Port of Providence (Rhode Island), Paulsboro Marine 
Terminal (New Jersey), and/or Sparrows Point (Maryland).
     WTG Tower, Nacelle, and Blade Storage, Pre-commissioning, 
and Marshalling: Port of Providence (Rhode Island), Port of New London 
(Connecticut), Port of Norfolk (Virginia), and/or New Bedford Marine 
Commerce Terminal (Massachusetts).
     Electrical Components: Port of Providence (Rhode Island).
    Vessels not transporting material from the ports listed above may 
travel with components and equipment directly to the lease area from 
locations such as the Gulf of Mexico, Europe, or other worldwide ports. 
Before arriving at the lease area, a port call for inspections,

[[Page 79082]]

crew transfers and bunkering may occur (Revolution Wind 2022).
    Construction vessel traffic would result in a relatively localized 
impact which would occur sporadically throughout the approximate 18-
month time period of offshore construction in and around the RWF, 
temporarily increasing the volume and movement of vessels. Large work 
vessels for foundation and WTG installation would generally transit to 
the lease area and remain in the area until installation is complete. 
These large vessels would move slowly over a short distance between 
work locations within the lease area. Crew transport vessels would 
travel between several ports and the RWF over the course of the 
construction period following mandatory vessel speed restrictions, as 
described in the Proposed Mitigation section below. These vessels would 
range in size from smaller crew transport vessels, to tug and barge 
vessels. However, Revolution Wind has confirmed that construction crews 
would hotel onboard installation vessels at sea, thus limiting the 
number of crew vessel transits expected (870 round-trips during the 
construction and 300 round trips during non-construction years) during 
the effective period of the proposed rule.
    Vessels would comply with NMFS' regulations and state regulations 
as applicable for North Atlantic right whales (hereinafter ``right 
whale,'' or ``right whales'') and additional measures included in this 
proposed rule. The total number of estimated round trips for all 
vessels during the construction (scheduled for Year 1) and non-
construction years (Year 2-5) is 1,406 and 444, respectively.

    Table 3--Type and Number of Vessels, and Number of Vessel Trips,
                     Anticipated During Construction
                         [Scheduled for Year 1]
------------------------------------------------------------------------
                                                       Number of  return
             Vessel types                 Number of    trips  per vessel
                                           vessels            type
------------------------------------------------------------------------
                  Wind Turbine Foundation Installation
------------------------------------------------------------------------
Heavy Lift Installation Vessel.......               1                  1
?Heavy Lift Installation Vessel                     1                  1
 (secondary steel)...................
Towing Tug (for fuel barge)..........               1                 10
Anchor Handling Tug..................               2                 50
Vessel for Bubble Curtain............               1                 20
Heavy Transport Vessel...............               4                 25
Crew Transport Vessel................               1                 30
PSO Vessel...........................               4                 80
Platform Supply Vessel (secondary                   2                 65
 steel)..............................
Platform Supply Vessel (completions).               1                 20
Fall Pipe Vessel.....................               1                  6
------------------------------------------------------------------------
                          Turbine Installation
------------------------------------------------------------------------
Jack-up Installation Vessel..........               1                 20
Fuel Bunkering Vessel................               1                  8
Towing Tug (for fuel barge)..........               1                  8
------------------------------------------------------------------------
                        Array Cable Installation
------------------------------------------------------------------------
Pre-Lay Grapnel Run..................               1                  4
Boulder Clearance Vessel.............               1                 10
Sandwave Clearance Vessel............               1                  2
Cable Laying Vessel..................               1                  6
Cable Burial Vessel..................               1                  6
Crew Transport Vessel................               1                231
Walk to Work Vessel (SOV)............               1                  6
Survey Vessel........................               1                  8
DP2 Construction Vessel..............               1                  5
------------------------------------------------------------------------
                        OSS Topside Installation
------------------------------------------------------------------------
Heavy Transport Vessel...............               1                  1
------------------------------------------------------------------------
                   Offshore Export Cable Installation
------------------------------------------------------------------------
Pre-Lay Grapel Run...................               1                  2
Boulder Clearance Vessel.............               1                  3
Sandwave Clearance Vessel............               1                  1
Cable Lay and Burial Vessel..........               1                  5
Cable Burial Vessel--Remedial........               1                  1
Cable Lay Barge......................               1                  3
Tug--Small Capacity..................               2                  3
Tug--Large Capacity..................               1                  8
Crew Transport Vessel................               1                214
Guard Vessel/Scout Vessel............               5                  8
Survey Vessel........................               1                  3
DP2 Construction Vessel..............               1                  3
Supply Barge.........................               1                  4
------------------------------------------------------------------------

[[Page 79083]]

 
                     All Construction Activities \1\
------------------------------------------------------------------------
Safety Vessel........................               2                100
Crew Transport Vessel................               3                395
Supply Vessel........................               1                 30
Service Operation Vessel.............               1                  1
Helicopter...........................               1                 76
------------------------------------------------------------------------
\1\ The vessels included in the ``All Construction Activities'' section
  provide general support across all of the activities in Table 3. The
  vessels listed in each activity (e.g., ``Wind Turbine Foundation
  Installation'' are solely utilized for that activity.


  Table 4--Type and Number of Vessels, and Number of Vessel Trips, Anticipated During Scheduled Operations and
                                             Maintenance Activities
                                                   [Years 2-5]
----------------------------------------------------------------------------------------------------------------
                                                                            Number of return    Total number  of
                       Vessel type                            Number of     trips per vessel   return trips  for
                                                               vessels        type per year        years 2-5
----------------------------------------------------------------------------------------------------------------
Service Operation Vessel.................................               1                  26                104
Crew Transport Vessel....................................               1                  62                248
Shared Crew Transport Vessel.............................             0.5                  13                 52
Daughter Craft...........................................               1                  10                 40
----------------------------------------------------------------------------------------------------------------

    While marine mammals are known to respond to vessel noise and the 
presence of vessels in different ways, we do not expect Revolution 
Wind's vessel operations to result in the take of marine mammals. As 
existing vessel traffic in the vicinity of the project area off Rhode 
Island and Massachusetts is relatively high, we expect that marine 
mammals in the area are likely somewhat habituated to vessel noise. In 
addition, any construction vessels would be stationary for significant 
periods of time when on-site and any large vessels would travel to and 
from the site at relatively low speeds. Project-related vessels would 
be required to adhere to 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 the 
Proposed Mitigation section). Given the implementation of these 
measures, vessel strikes are neither anticipated nor proposed to be 
authorized (see Potential Effects of Vessel Strike section).
    As part of various vessel-based construction 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 harassment. Construction-related vessel activity, including the use 
of dynamic positioning thrusters, is not expected to result in take of 
marine mammals and Revolution Wind did not request, and NMFS does not 
propose to authorize, any take associated with construction vessel 
activity. However, NMFS acknowledges the aggregate impacts of 
Revolution Wind's vessel operations on the acoustic habitat of marine 
mammals and has considered it in the analysis.
    Revolution Wind has also included the potential use of an 
Autonomous Surface Vehicle (ASVs), a small unmanned surface vessel or 
platform, during HRG surveys. Should an ASV be utilized during surveys, 
it would be positioned within 800 m (2,625 ft) of the primary vessel 
while conducting survey operations, operated at a slow speed, and would 
be monitored by PSOs at all times. Revolution Wind did not request take 
specific to ASVs and NMFS is not proposing to authorize take associated 
with ASV operation.
Fisheries and Benthic Habitat Monitoring
    As described in section 1.1.7 of Revolution Wind's ITA application, 
the fisheries and benthic monitoring efforts Revolution Wind plans to 
conduct throughout the proposed rule's period of effectiveness have 
been designed for the Project in accordance with recommendations set 
forth in ``Guidelines for Providing Information on Fisheries for 
Renewable Energy Development on the Atlantic Outer Continental Shelf'' 
(BOEM 2019). In particular, Revolution Wind's Fisheries and Benthic 
Monitoring Plan includes four elements: trawl surveys, an acoustic 
telemetry study, ventless trap surveys, and benthic habitat monitoring. 
Trawl surveys would be focused on sampling the fish and invertebrate 
community within the Project area. For the acoustic telemetry study, 
Highly Migratory Species (bluefin tuna, shortfin mako, and blue sharks) 
would be tagged during the trawl survey, after which Revolution Wind 
would use a combination of fixed station receivers and active mobile 
telemetry to assess the movements of these species. Revolution Wind 
would deploy up to 100 additional acoustic tags opportunistically for 
cod caught as part of trawl survey. The ventless trap survey would be 
conducted twice per month between May and November to investigate the 
relative abundance of

[[Page 79084]]

lobster, Jonah crab, and rock crab. Ten trap trawls (6 ventless and 4 
vented) would be fished on a five-day soak time. Finally, hard bottom 
habitat monitoring would occur, during which Revolution Wind would use 
a remotely operated vehicle (ROV) and video surveying approach to 
characterize changes from pre-construction conditions. Soft bottom 
habitat monitoring would be conducted using Sediment Profile and Plan 
View Imaging (SPI/PV) to document physical (and biological change 
related to construction of the Project. Because the gear types and 
equipment used for the acoustic telemetry study and benthic habitat 
monitoring do not have components with which marine mammals are likely 
to interact (i.e., become entangled in or hooked by), these activities 
are unlikely to have any impacts on marine mammals.
    Of the activities described, trawl and ventless trap surveys could 
have the potential to impact marine mammals through interactions with 
fishing gear (i.e., entanglement). However, Revolution Wind has 
proposed, and would be required, to implement Best Management Practices 
(BMPs) that would minimize this risk to the degree that take of marine 
mammals is not reasonably anticipated. Given these BMPs (included in 
the Proposed Mitigation section), neither NMFS nor Revolution Wind 
anticipates that any take is likely to occur incidental to the 
activities described herein and in section 1.1.7 of the ITA application 
(Revolution Wind, 2021). Additionally, Revolution Wind has not 
requested any take of marine mammals incidental to fisheries surveys 
and benthic habitat monitoring, nor does NMFS propose to authorize any 
take given the nature of the activities and, for certain gear types, 
Revolution Wind's planned mitigation measures. Therefore, aside from 
the mitigation measures provided in the Proposed Mitigation section, 
these activities are not analyzed further in this document.
Dredging
    Dredging may be used to remove materials from the seafloor in 
preparation of offshore foundation and export cable locations. There 
are two fundamental types of dredging that could be used by the 
Project--mechanical and hydraulic. Mechanical dredging refers to crane-
operated buckets, grabs (clamshell), or backhoes used to remove 
seafloor material. Hydraulic (suction) dredging and controlled flow 
excavation (CFE) dredging involve the use of a suction to either remove 
sediment from the seabed or relocate sediment from a particular 
location on the seafloor. There are a variety of hydraulic and CFE 
dredge types including trailing suction, cutter-suction, auger suction, 
jet-lift, and air-lift (Kusel et al., 2021). The sound produced by 
hydraulic dredging results from the combination of sounds generated by 
the impact and abrasion of the sediment passing through the draghead, 
suction pipe, and pump.
    NMFS does not expect dredging to generate noise levels that would 
cause take of marine mammals. Most of the acoustic energy produced by 
dredging falls below 1 kHz, and is highly unlikely to cause damage to 
marine mammal hearing (Todd et al., 2015). For example, a study by 
Reine and Clarke (2014) found that, using a propagation loss 
coefficient of 15LogR, source levels of dredging operations in the 
shallow waters (less than 15 m depth) in New York Harbor were measured 
at and did not exceed 151 dB re 1 [mu]Pa, which is not expected to 
cause hearing shifts in marine mammals. A more recent analysis by 
McQueen et al. (2020) found that, using a maximum sound level of 192 dB 
re 1 [mu]Pa, the resulting isopleths for representative marine mammals 
(i.e., the harbor seal and harbor porpoise), the resulting isopleths 
for temporary shifts in hearing would occur less than 20 m and less 
than 74 m, respectively. Isopleths for permanent shifts occurred at 
distances of less than 1 m for both marine mammal species.
    While NMFS acknowledges the potential for masking or slight 
behavioral changes to occur during dredging activities (Todd et al., 
2015), any effects on marine mammals are expected to be short-term, low 
intensity, and unlikely to qualify as a take. Given the size of the 
area in which dredging operations would be occurring, as well as the 
coastal nature of some of these activities for the nearshore sea-to-
shore connection points related to temporary cofferdam installation/
removal, NMFS expects that any marine mammals would not be exposed at 
levels or durations likely to disrupt normal life activities (i.e., 
migrating, foraging, calving, etc.). Therefore, the potential for take 
of marine mammals to result from these activities is so low as to be 
discountable. Revolution Wind did not request, and NMFS does not 
propose to authorize, any take of marine mammals associated with 
dredging; dredging activities are not analyzed further in this 
document.
Boulder Clearance
    Boulder clearance may occur prior to and during offshore 
installation construction activities associated with the RWEC, 
foundation preparation, and the inter-array cable and OSS-Link cable 
installation, during which a number of different vessels and equipment 
types would be utilized. The techniques that may be used to remove or 
relocate surface or partially embedded boulders and debris, primarily 
during installation of the RWEC, include using a Boulder Grab or a 
Boulder Plow. The Boulder Grab would be lowered to the seabed over a 
targeted boulder, then grab the boulder to relocate it to a site away 
from the RWEC corridor. Alternatively, boulder clearance could be 
accomplished using a high-bollard pull vessel with a towed plow 
generally forming an extended V-shaped configuration, splaying from the 
rear of the main chassis (i.e., Boulder Plow). The V-shaped 
configuration displaces any boulders to the extremities of the plow, 
thus clearing the corridor. Multiple iterations of this process may be 
required to clear a particular section of the corridor. A tracked plow 
with a front blade similar to a bulldozer may also be used to push 
boulders away from the corridor. Based on Revolution Wind's review of 
site-specific geophysical data, it is assumed that a boulder plow may 
be used in all areas of higher boulder/debris concentrations, 
conservatively estimated to be up to 60 percent per cable route of the 
RWEC and 80 percent of the entire inter-array cable network. Both 
within these areas of higher boulder and debris concentrations and 
outside of these areas, a boulder grab may be used to remove larger 
and/or isolated targets. The size of boulders that can be relocated is 
dependent on a number of factors including the boulder weight, 
dimensions, embedment, density and ground conditions. Typically, 
boulders with dimensions less than 8 ft (2.5 m) can be relocated with 
standard tools and equipment.
    NMFS does not expect boulder clearance to generate noise levels 
that would cause take of marine mammals. Underwater noise associated 
with boulder clearance is expected to be similar in nature to the sound 
produced by the dynamic positioning (DP) cable lay vessels used during 
cable installation activities within the RWEC. Sound produced by DP 
vessels is considered non-impulsive and is typically more dominant than 
mechanical or hydraulic noises produced from the cable trenching or 
boulder removal vessels and equipment. Therefore, noise produced by the 
high bollard pull vessel with a towed plow or a support vessel carrying 
a boulder grab would be comparable to or less than the noise produced 
by DP vessels,

[[Page 79085]]

so impacts are also expected to be similar. Boulder clearance is a 
discrete action occurring over a short duration resulting in short term 
direct effects. Additionally, sound produced by boulder clearance 
vessels and equipment 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. The Revolution Wind DEIS 
(BOEM, 2022), issued by BOEM on September 2, 2022, discusses boulder 
clearance in multiple sections, providing summaries of the boulder 
clearance methodologies described in Revolution Wind's COP. BOEM has 
deemed boulder clearance activities as a non-noise generating activity; 
therefore, the DEIS does not describe boulder clearance activities as a 
source of noise impacts (BOEM, 2022).
    While NMFS acknowledges the potential for slight behavioral changes 
to occur during boulder clearance, any effects on marine mammals are 
expected to be short-term, low intensity, and unlikely to qualify as a 
take. Given that boulder clearance is expected to be extremely 
localized at any given time, NMFS expects that any marine mammals would 
not be exposed at levels or durations likely to disrupt normal life 
activities (i.e., migrating, foraging, calving, etc.). Therefore, the 
potential for take of marine mammals to result from these activities is 
so low as to be discountable. Revolution Wind did not request, and NMFS 
does not propose to authorize, any take associated with boulder 
clearance; therefore, boulder clearance activities are not analyzed 
further in this document.
Cable Laying and Installation
    Cable burial operations would occur both in RWF for the inter-array 
cables connecting the 79 WTGs to the two OSSs, and in the RWEC corridor 
for cables carrying power from the OSSs to shore. A single offshore 
export cable would connect the OSSs to the sea-to-shore transition 
point in Quonset Point, Rhode Island. All cable burial operations would 
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.
    All cables would be buried below the seabed, when possible, and 
buried onshore up to the transition joint bays. The targeted burial 
depths would be determined later by Revolution Wind, following a 
detailed design and Cable Burial Risk Assessment. This Assessment would 
note where burial cannot occur, where sufficient depths cannot be 
achieved, and/or where additional protection is required due to the 
export cable crossing other cables or pipelines (either related to the 
Revolution Wind project or not). Burial of cables would be performed by 
specific vessels, which are described in Table 3.3.10-3 in the 
Revolution Wind COP, available at: https://www.boem.gov/renewable-energy/state-activities/revolution-wind-farm-construction-and-operations-plan.
    Cable laying, cable installation, and cable burial activities 
planned to occur during the construction of Revolution Wind may include 
the following:
     Jetting;
     Vertical injection;
     Leveling;
     Mechanical cutting;
     Plowing (with or without jet-assistance);
     Pre-trenching; and,
     Controlled flow excavation.
    Some dredging may be required prior to cable laying due to the 
presence of sandwaves. Sandwave clearance may be undertaken where cable 
exposure is predicted over the lifetime of the Project due to seabed 
mobility. This facilitates cable burial below the reference seabed. 
Alternatively, sandwave clearance may be undertaken where slopes become 
greater than approximately 10 degrees (17.6 percent), which could cause 
instability to the burial tool. The work could be undertaken by 
traditional dredging methods such as a trailing suction hopper. 
Alternatively, controlled flow excavation or a sandwave removal plough 
could be used. In some cases, multiple passes may be required. The 
method of sandwave clearance Revolution Wind chooses would be based on 
the results from the site investigation surveys and cable design. More 
information on cable laying associated with the proposed project is 
provided in Revolution Wind's COP (Revolution Wind, 2022) available at 
https://www.boem.gov/renewable-energy/state-activities/revolution-wind-farm-construction-and-operations-plan.
    As the noise levels generated from this activity are low, the 
potential for take of marine mammals to result is discountable (86 FR 
8490; February 5, 2021) and Revolution Wind did not request, and NMFS 
is not proposing to authorize, marine mammal take associated with cable 
laying. Therefore, cable laying activities are not analyzed further in 
this document.
Helicopter Flights
    Helicopters may be used during RWF construction and operation 
phases for crew transfer activities to provide a reduction in the 
overall transfer time, as well as to reduce the number of vessels on 
the water. Two of the closest ports to the Revolution Wind lease area 
are the Port of Davisville at Quonset Point, RI, and New Bedford, MA. 
Both of these are located approximately 45 km (28 mi) from the nearest 
portion of the lease area and 70-80 km (44-49 mi) from the most distant 
parts of the lease area. Assuming a vessel speed of 10 knots, a one-way 
trip from one of these ports by vessel would require between 2.4 and 
4.3 hours. Typical crew transfer helicopters are capable of maximum 
cruising speeds of approximately 140 knots. Assuming a somewhat slower 
speed of 120 knots, a one-way trip by helicopter would require 12-22 
minutes, thus reducing transit time by 92 percent (Revolution Wind, 
2022c).
    Without the use of helicopters, all crew transfers to/from offshore 
locations would be conducted by vessel (either a dedicated crew 
transfer vessel or other project vessel transiting between a port and 
the offshore location). Tables 3 and 4 reflect the use of helicopters; 
therefore, if Revolution Wind did not use helicopters, the amount of 
crew vessel activity would be higher. Use of helicopters may be limited 
by many factors, such as logistical constraints (e.g., ability to land 
on the vessels) and weather conditions that affect flight operations 
(Revolution Wind, 2022c). Helicopter use also adds significant health, 
safety and environment (HSE) risk to personnel and, therefore, requires 
substantially more crew training and additional safety procedures 
(Revolution Wind, 2022c). These factors can result in significant 
limitations to helicopter usage. To maintain construction schedules and 
reliable wind farm operations, the necessity for crew transfers, by 
vessels or helicopter, would remain a core component of offshore wind 
farm construction and operations.
    Helicopters produce sounds that could be audible to marine mammals. 
Sound generated by aircraft, both fixed wing and helicopters, is 
produced in air, but can transmit through the water surface and 
propagate underwater. In general, underwater sound levels produced by 
fixed wing aircraft and helicopters are typically low-frequency (16-500 
Hz) and range between 84-159 dB re 1 [mu]Pa (Richardson et al., 1995; 
Patenaude et al., 2002; Erbe et al., 2018). However, most sound energy 
from aircraft reflects off the air-water

[[Page 79086]]

interface; only sound radiated downward within a 26-degree cone 
penetrates below the surface water (Urick, 1972). To the extent noise 
from helicopters transmits from air through the water surface, there is 
potential to cause temporary changes in behavior and localized 
displacement of marine mammals (Richardson et al., 1985a; Richardson 
and W[uuml]rsig, 1997; Nowacek et al., 2007).
    Marine mammals tend to react to aircraft noise more often when the 
aircraft is lower in altitude, closer in lateral distance, and flying 
over shallow water (Richardson et al., 1985b; Patenaude et al., 2002). 
Temporary reactions by marine mammals may include short surfacing, 
hasty dives, aversion from the aircraft or dispersal from the incoming 
aircraft (Bel'kovich, 1960; Kle[ibreve]nenberg et al., 1964; Richardson 
et al., 1985a; Richardson et al., 1985b; Luksenburg and Parsons, 2009). 
The response of marine mammals to aircraft noise largely depends on the 
species as well as the animal's behavioral state at the time of 
exposure (e.g., migrating, resting, foraging, socializing) (W[uuml]rsig 
et al., 1998). A study conducted in the Beaufort Sea in northern Alaska 
observed a general lack of reaction in bowhead and beluga whales to 
passing helicopters (Patenaude et al., 2002). Patenaude et al. (2002) 
reported behavioral responses by only 17 percent of the observed 
bowhead whales to passing helicopters at altitudes below 150 m and 
within a lateral distance of 250 m. Similarly, most observed beluga 
whales did not show any visible reaction to helicopters passing when 
flight altitudes were over 150 m (Patenaude et al., 2002). Although the 
sound emitted by aircraft has the potential to result in temporary 
behavioral responses in marine mammals, project-related aircraft would 
only occur at low altitudes over water during takeoff and landing at an 
offshore location where one or more vessels are located. Due to the 
intermittent nature of helicopter flights, the higher altitude, and the 
small area potentially ensonified by this sound source, both Revolution 
Wind and NMFS expect the potential for take of marine mammals 
incidental to helicopter use to be discountable. The use of helicopters 
to conduct crew transfers is likely to provide an overall benefit to 
marine mammals in the form of reduced vessel activity. Revolution Wind 
did not request, and NMFS is not proposing to authorize, take of marine 
mammals incidental to Revolution Wind's use of helicopters. This 
activity is not discussed or analyzed further herein.

Description of Marine Mammals in the Area of Specified Activities

    Forty marine mammal species and/or stocks have geographic ranges 
within the western North Atlantic OCS (Table 5 in Revolution Wind ITA 
application). However, for reasons described below, Revolution Wind has 
requested, and NMFS proposes to authorize, take of only 16 species 
(comprising 16 stocks). Sections 3 and 4 of Revolution Wind's 
application summarize available information regarding status and 
trends, distribution and habitat preferences, and behavior and life 
history of the potentially affected species. NMFS fully considered all 
of this information, and we refer the reader to these descriptions in 
the application, incorporated here by reference, instead of reprinting 
the information. Additional information regarding population trends and 
threats may be found in NMFS's Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species 
(e.g., physical and behavioral descriptions) may be found on NMFS's 
website (https://www.fisheries.noaa.gov/find-species).
    Table 5 lists all species and stocks for which take is expected and 
proposed to be authorized for this action, and summarizes information 
related to the population or stock, including regulatory status under 
the MMPA and Endangered Species Act (ESA) and potential biological 
removal (PBR), where known. 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 16 
U.S.C. 1362(20) and as described in NMFS' SARs. While no mortality is 
anticipated or authorized here, PBR and annual serious injury and 
mortality from anthropogenic sources are included here as gross 
indicators of the status of the species and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS' 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 and Gulf of Mexico SARs. All values presented in 
Table 5 are the most recent available at the time of publication and 
are available in NMFS' 2021 SARs (Hayes et al., 2022), available online 
at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports.

                 Table 5--Marine Mammal Species Likely To Occur Near the Project Area That May Be Taken by Revolution Wind's Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                        ESA/ MMPA  status;  Stock  abundance  (CV,
             Common name                  Scientific name               Stock             strategic  (Y/N)     Nmin, most recent       PBR     Annual  M/
                                                                                                \1\          abundance survey) \2\               SI \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                           Order Artiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenidae:
    North Atlantic right whale......  Eubalaena glacialis....  Western Atlantic.......  E, D, Y             368 (0; 364; 2019) \          0.7        7.7
                                                                                                             5\.
Family Balaenopteridae (rorquals):
    Blue whale......................  Balaenoptera musculus..  Western North Atlantic.  E, D, Y             UNK (UNK; 402; 1980-          0.8          0
                                                                                                             2008).
    Fin whale.......................  Balaenoptera physalus..  Western North Atlantic.  E, D, Y             6,802 (0.24; 5,573;            11        1.8
                                                                                                             2016).
    Sei whale.......................  Balaenoptera borealis..  Nova Scotia............  E, D, Y             6,292 (1.02; 3,098;           6.2        0.8
                                                                                                             2016).
    Minke whale.....................  Balaenoptera             Canadian Eastern         -, -, N             21,968 (0.31; 17,002;         170       10.6
                                       acutorostrata.           Coastal.                                     2016).

[[Page 79087]]

 
    Humpback whale..................  Megaptera novaeangliae.  Gulf of Maine..........  -, -, Y             1,396 (0; 1,380; 2016)         22      12.15
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Physeteridae:
    Sperm whale.....................  Physeter macrocephalus.  North Atlantic.........  E, D, Y             4,349 (0.28; 3,451;           3.9          0
                                                                                                             2016).
Family Delphinidae:
    Atlantic white-sided dolphin....  Lagenorhynchus acutus..  Western North Atlantic.  -, -, N             93,233 (0.71; 54,433;         544         27
                                                                                                             2016).
    Atlantic spotted dolphin........  Stenella frontalis.....  Western North Atlantic.  -, -, N             39,921 (0.27; 32,032;         320          0
                                                                                                             2016).
    Common bottlenose dolphin.......  Tursiops truncatus.....  Western North Atlantic   -, -, N             62,851 (0.23; 51,914;         519         28
                                                                Offshore.                                    2016).
    Long-finned pilot whales........  Globicephala melas.....  Western North Atlantic.  -, -, N             39,215 (0.3; 30,627;          306         29
                                                                                                             2016).
    Risso's dolphin.................  Grampus griseus........  Western North Atlantic.  -, -, N             35,215 (0.19; 30,051;         301         34
                                                                                                             2016).
    Common dolphin (short-beaked)...  Delphinus delphis......  Western North Atlantic.  -, -, N             172,897 (0.21;              1,452        390
                                                                                                             145,216; 2016).
Family Phocoenidae (porpoises):
    Harbor porpoise.................  Phocoena phocoena......  Gulf of Maine/Bay of     -, -, N             95,543 (0.31; 74,034;         851         16
                                                                Fundy.                                       2016).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals):
    Gray seal \4\...................  Halichoerus grypus.....  Western North Atlantic.  -, -, N             27,300 (0.22; 22,785;       1,389      4,453
                                                                                                             2016).
    Harbor seal.....................  Phoca vitulina.........  Western North Atlantic.  -, -, N             61,336 (0.08; 57,637;       1,729        339
                                                                                                             2018).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or
  designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or
  which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is
  automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments
  (Hayes et al., 2022). CV is the coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable.
\3\ These values, found in NMFS' SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial
  fisheries, ship strike).
\4\ NMFS' stock abundance estimate (and associated PBR value) applies to the U.S. population only. Total stock abundance (including animals in Canada)
  is approximately 451,431. The annual M/SI value given is for the total stock.
\5\ The draft 2022 SARs have yet to be released; however, NMFS has updated its species web page to recognize the population estimate for right whales is
  now below 350 animals (https://www.fisheries.noaa.gov/species/north-atlantic-right-whale).
\6\ Information on the classification of marine mammal species can be found on the web page for the Society for Marine Mammalogy's Committee on Taxonomy
  (https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/; Committee on Taxonomy (2022)).

    Of the 40 marine mammal species and/or stocks with geographic 
ranges that include the western North Atlantic OCS (Table 5 in 
Revolution Wind ITA application), 24 are not expected to be present or 
are considered rare or unexpected in the project area based on sighting 
and distribution data; 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 RWF and RWEC corridor, based on the best available 
information: dwarf and pygmy sperm whales (Kogia sima and K breviceps), 
northern bottlenose whale (hyperoodon ampullatus), cuvier's beaked 
whale (Ziphius cavirostris), four species of Mesoplodont beaked whales 
(Mesoplodon densirostris, M. europaeus, M. mirus, and M. bidens), 
killer whale (Orcinus orca), false killer whale (Pseudorca crassidens), 
pygmy killer whale (Feresa attenuata), short-finned pilot whale 
(Globicephala Macrohynchus), melon-headed whale (Peponocephala 
electra), Fraser's dolphin (Lagenodelphis hosei), white-beaked dolphin 
(Lagenorhynchus albirostris), pantropical spotted dolphin (Stenella 
attenuata), Clymene dolphin (Stenella Clymene), striped dolphin 
(Stenella coeruleoalba), spinner dolphin (Stenella longirostris), 
rough-toothed dolphin (Steno bredanensis), and the coastal migratory 
stock of common bottlenose dolphins (Tursiops truncatus truncatus). 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 (Globicephala melas) and short-finned 
(Globicephala macrorhynchus), with distributions that overlap in the 
latitudinal range of the RWF (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. (Roberts et al., 2016; 
Hayes et al., 2020). 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; a sub-species 
of the West Indian manatee) has been previously documented as an 
occasional visitor to the Northeast region during summer months (U.S. 
Fish and Wildlife Service (USFWS), 2022). However, manatees are managed 
by the USFWS

[[Page 79088]]

and are not considered further in this document. More information on 
this species can be found at the following website: https://www.fws.gov/species/manatee-trichechus-manatus.
    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 RWF 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 24 species listed above reinforces the fact 
that they are not expected to occur in the project area. In addition, 
none of these species were observed during HRG surveys conducted by 
[Oslash]rsted from 2018 to 2021. As these species are not expected to 
occur in the project area during the proposed activities (based on 
acoustic detection and PSO data), NMFS does not propose to authorize 
take of these species and they are not discussed further in this 
document.
    As indicated above, all 16 species and stocks in Table 5 temporally 
and spatially co-occur with the activity to the degree that taking is 
reasonably likely to occur. Five of the marine mammal species for which 
take is requested have been designated as ESA-listed, including North 
Atlantic right, blue, fin, sei, and sperm whales. In addition to what 
is included in Sections 3 and 4 of Revolution Wind's ITA application 
(https://www.fisheries.noaa.gov/action/incidental-take-authorization-revolution-wind-llc-construction-revolution-wind-energy), the SARs 
(https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments), and NMFS' website (https://www.fisheries.noaa.gov/species-directory/marine-mammals), we provide 
further detail below informing the baseline for select species (e.g., 
information regarding current Unusual Mortality Events (UME) and known 
important habitat areas, such as Biologically Important Areas (BIAs) 
(Van Parijs et al., 2015)). There is no ESA-designated critical habitat 
for any species within the project area.
    Under the MMPA, a UME is defined as ``a stranding that is 
unexpected; involves a significant die-off of any marine mammal 
population; and demands immediate response'' (16 U.S.C. 1421h(6)). As 
of December 2022, seven UMEs in total are considered active, with five 
of these occurring along the U.S. Atlantic coast for various marine 
mammal species; of these, the most relevant to the Revolution Wind 
project are the minke, right, and humpback whale, and phocid seal UMEs, 
given the prevalence of these species in the project area. More 
information on UMEs, including all active, closed, or pending, can be 
found on NMFS' website at https://www.fisheries.noaa.gov/national/marine-life-distress/active-and-closed-unusual-mortality-events.
    Below we include information for a subset of the species that 
presently have an active or recently closed UMEs occurring along the 
Atlantic coast, or for which there is information available related to 
areas of biological significance. 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 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 areas of known biological importance (including 
the Biologically Important Areas (BIAs) identified in Van Parijs et 
al., 2015 and LaBrecque et al., 2015) that overlap spatially with the 
project area are addressed in the species sections below.
North Atlantic Right Whale
    The North Atlantic right whale has been listed as an Endangered 
since 1970. They were recently uplisted from Endangered to Critically 
Endangered on the International Union for Conservation of Nature (IUCN) 
Red List of Threatened Species (Cooke, 2020). The uplisting was due to 
a decrease in population size (Pace et al., 2017), an increase in 
vessel strikes and entanglements in fixed fishing gear (Daoust et al., 
2017; Davies & Brillant, 2019; Knowlton et al., 2012; Sharp et al., 
2019), and a decrease in birth rate (Pettis et al., 2021). The Western 
Atlantic stock is considered depleted under the MMPA (Hayes et al., 
2021). There is a recovery plan (NOAA Fisheries 2017) for the North 
Atlantic right whale, and NMFS completed a 5-year review of the species 
in 2017 (NOAA Fisheries 2017). In February 2022, NMFS initiated a 5-
year review process (https://www.fisheries.noaa.gov/action/initiation-5-year-review-north-atlantic-right-whale).
    The right whale population had only a 2.8 percent recovery rate 
between 1990 and 2011 (Hayes et al., 2022). Since 2010, the North 
Atlantic right whale population has been in decline (Pace et al., 
2017), with a 40 percent decrease in calving rate (Kraus et al., 2016). 
In 2018, no new right whale calves were documented; this represented 
the first time since annual NOAA aerial surveys began in 1989 that no 
new right whale calves were observed within a calving season. 
Presently, the best available peer-reviewed population estimate for 
North Atlantic right whales is 368 per the 2021 SARs (Hayes et al., 
2021) (https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments). The draft 2022 SARs have 
yet to be released; however, NMFS has updated its species web page to 
acknowledge that the right whale population estimate is now below 350 
animals (https://www.fisheries.noaa.gov/species/north-atlantic-right-whale). We note that this change in abundance estimate would not change 
the estimated take of right whales or the take NMFS has proposed to 
authorize as take estimates are based on the habitat density models 
(Roberts et al., 2016; Roberts and Halpin, 2022).
    Right whale presence in the project area is predominately seasonal; 
however, year-round occurrence is documented (O'Brien et al., 2022, 
Quintano-Rizzo et al., 2021). As a result of recent years of aerial 
surveys and PAM deployments within the RI/MA WEA, we have confidence 
that right whales are expected in the project area, in higher numbers 
in winter and spring followed by decreasing abundance into summer and 
early fall. The project area both spatially and temporally overlaps a 
portion of the migratory corridor BIA and migratory route Seasonal 
Management Area (SMA), within which right whales migrate south to 
calving grounds generally in November and December, followed by a 
northward migration into feeding areas east and north of the project 
area in March and April (LaBrecque et al., 2015; Van Parijs et al., 
2015). While the project does not overlap previously identified 
critical feeding habitat or a feeding BIA, it is located just west of a 
more recently described important feeding area south of Martha's 
Vineyard and Nantucket,

[[Page 79089]]

along the western side of Nantucket Shoals. Finally, the project 
overlaps the Block Island SMA, which may be used by right whales for 
various activities, including feeding and migration. Due to the current 
status of North Atlantic right whales, and the overlap of the proposed 
project with areas of biological significance (i.e., a migratory 
corridor, SMA), the potential impacts of the proposed project on right 
whales warrant particular attention.
    Elevated right whale mortalities have occurred since June 7, 2017, 
along the U.S. and Canadian coast, with the leading category for the 
cause of death for this UME determined to be ``human interaction,'' 
specifically from entanglements or vessel strikes. As of November 2022, 
there have been 34 confirmed mortalities (dead stranded or floaters; 21 
in Canada; 13 in the United States) and 21 seriously injured free-
swimming whales for a total of 55 whales. As of November 15, 2022, the 
UME also considers animals with sublethal injury or illness bringing 
the total number of whales in the UME to 92. Approximately 42 percent 
of the population is known to be in reduced health (Hamilton et al., 
2021), likely contributing to the smaller body sizes at maturation 
(Stewart et al., 2022) and making them more susceptible to threats. 
More information about the North Atlantic right whale UME is available 
online at: www.fisheries.noaa.gov/national/marine-life-distress/2017-2021-north-atlantic-right-whale-unusual-mortality-event.
    North Atlantic right whales may be present in New England waters 
year-round; however, their presence is limited during summer months. 
These waters are both a migratory corridor in the spring and early 
winter and a primary feeding habitat for right whales during late 
winter through spring. Habitat-use patterns within the region have 
shifted in relatively recent years (Davis et al., 2020; Quintano-Rizzo 
et al., 2021; O'Brien et al., 2022). Since 2010, right whales have 
reduced their use of foraging habitats in the Great South Channel and 
Bay of Fundy, while increasing their use of habitat within Cape Cod 
Bay, as well as a region south of Martha's Vineyard and Nantucket 
Islands, just to the east of the RWF and RWEC corridor (Stone et al., 
2017; Mayo et al., 2018; Ganley et al., 2019; Record et al., 2019; 
Meyer-Gutbrod et al., 2021). Pendleton et al. (2022) found that peak 
use of right whale foraging habitat in Cape Cod Bay has shifted over 
the past 20 years to later in the spring, likely due to variations in 
seasonal conditions. Right whales have recently been observed feeding 
year-round in the region south of Martha's Vineyard and Nantucket with 
larger numbers in this area in the winter, making it the only known 
winter foraging habitat for the species (Quintana-Rizzo et al., 2021). 
Right whale use of habitats such as in the Gulf of St. Lawrence and 
East Coast mid-Atlantic waters of the have also increased over time 
(Davis et al., 2017; Davis and Brillant, 2019; Crowe et al., 2021; 
Quintana-Rizzo et al., 2021). Simard et al. (2019) documented the 
presence of right whales in the southern Gulf of St. Lawrence foraging 
habitat from late April through mid-January annually from 2010-2018 
using passive acoustics, with occurrences peaking in the area from 
August through November each year (Simard et al., 2019). These shifts 
in foraging habitat use are likely due to changes in oceanographic 
conditions and food supply as dense patches of zooplankton are 
necessary for efficient foraging (Mayo and Marx, 1990; Record et al., 
2019). Observations of these transitions in 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).
    In late fall (i.e., November), a portion of the right whale 
population (including pregnant females) typically departs the feeding 
grounds in the North Atlantic, moves south along the migratory corridor 
BIA, including through the project area, to right whale calving grounds 
off Georgia and Florida. However, recent research indicates 
understanding of their movement patterns remains incomplete and not all 
of the population undergoes a consistent annual migration (e.g., Davis 
et al., 2017; Quintana-Rizzo et al, 2021). The results of multistate 
temporary emigration capture-recapture modeling, based on sighting data 
collected over the past 22 years, indicate that non-calving females may 
remain in the feeding grounds, during the winter in the years preceding 
and following the birth of a calf to increase their energy stores 
(Gowen et al., 2019).
    Within the project area, right whales have primarily been observed 
during the winter and spring seasons through recent visual surveys 
(Kraus et al., 2016; Quintana-Rizzo et al., 2021). During aerial 
surveys conducted in the RI/MA and MA WEAs from 2011-2015, the highest 
number of 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 
right whales. Despite the lack of visual detection, right whales were 
acoustically detected in 30 out of the 36 recorded months (Kraus et 
al., 2016). Since 2017, right whales have been sighted in the southern 
New England area nearly every month, with peak sighting rates between 
late winter and spring. Model outputs suggest that 23 percent of the 
right population is present from December through May, and the mean 
residence time has tripled to an average of 13 days during these months 
(Quintano-Rizzo et al., 2021). A hotspot analysis analyzing sighting 
data in southern New England from 2011-2019 indicated that right whale 
occurrence in the Revolution Wind project area was highest in the 
spring (March through May), and that few right whales were sighted in 
the area during that time frame in summer or winter (Quintano-Rizzo et 
al., 2021), a time when right whales distribution shifted to the east 
and south into other portions of the study area.
    North Atlantic right whale distribution can also be derived from 
acoustic data. A review of passive acoustic monitoring data from 2004 
to 2014 collected throughout the western North Atlantic demonstrated 
nearly continuous year-round right whale presence across their entire 
habitat range, 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 right 
whale vocalizations detected in southern New England were relatively 
constant throughout the year, with the exception of August through 
October when detected vocalizations showed an apparent decline (Davis 
et al., 2017).
    While density data from Roberts et al. (2022) confirm that the 
highest average density of right whales in the project area (both the 
lease area and RWEC corridor) occurs in March (0.0060 whales/100km\2\), 
which aligns with available sighting and acoustic data, it is clear 
that that habitat use is changing and right whales are present to some 
degree in or near the project area throughout the year, most notably 
south of Martha's Vineyard and Nantucket Islands (Leiter et al., 2017; 
Stone et al., 2017; Oleson et al., 2020, Quintano-Rizzo et al., 2021). 
Since 2010, right whale abundances have increased in

[[Page 79090]]

Southern New England waters, south of Martha's Vineyard and Nantucket 
Islands. O'Brien et al. (2022) detected significant increases in right 
whale abundance during winter and spring seasons from 2013-2019, likely 
due to changes in prey availability. Since 2017, right whales were also 
detected in small numbers during summer and fall, suggesting that these 
waters provide year-round habitat for right whales (O'Brien et al., 
2022).
    NMFS' regulations at 50 CFR 224.105 designated nearshore waters of 
the Mid-Atlantic Bight as Mid-Atlantic U.S. Seasonal Management Areas 
for right whales in 2008. SMAs were developed to reduce the threat of 
collisions between ships and right whales around their migratory route 
and calving grounds. As mentioned previously, the Block Island SMA 
overlaps spatially with the proposed project area (https://apps-nefsc.fisheries.noaa.gov/psb/surveys/MapperiframeWithText.html). The 
SMA is currently active from November 1 through April 30 of each year 
and may be used by right whales for feeding (although to a lesser 
extent than the area to the east near Nantucket Shoals) and/or 
migrating.
Humpback Whale
    Humpback whales are a cosmopolitan species found worldwide in all 
oceans, but 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.
    On September 8, 2016, NMFS divided the once single species into 14 
distinct population segments (DPS), removed the 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 whales that is expected to occur in 
the project area. Bettridge et al. (2015) estimated the size of the 
West Indies DPS population at 12,312 (95 percent CI 8,688-15,954) 
whales in 2004-05, which is consistent with previous population 
estimates of approximately 10,000-11,000 whales (Stevick et al., 2003; 
Smith et al., 1999) and the increasing trend for the West Indies DPS 
(Bettridge et al., 2015). 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 (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). Kraus et al. (2016) 
observed humpbacks in the RI/MA & MA Wind Energy Areas (WEAs) and 
surrounding areas during all seasons, but most often during spring and 
summer months, with a peak from April to June. Acoustic data indicate 
that this species may be present within the RI/MA WEA year-round, with 
the highest rates of acoustic detections in the winter and spring 
(Kraus et al., 2016).
    A humpback whale feeding BIA extends throughout the Gulf of Maine, 
Stellwagen Bank, and Great South Channel from May through December, 
annually (LeBrecque et al., 2015). However, this BIA is located further 
east and north of, and thus does not overlap, the project area. The 
project area does not overlap any critical habitat for the species.
    Since January 2016, elevated humpback whale mortalities along the 
Atlantic coast from Maine to Florida led to the declaration of a UME. 
Partial or full necropsy examinations have been conducted on 
approximately half of the 168 known cases (as of December 6, 2022). 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. More 
information is available at: www.fisheries.noaa.gov/national/marine-life-distress/2016-2021-humpback-whale-unusual-mortality-event-along-atlantic-coast.
Fin Whale
    Fin whales typically feed in the Gulf of Maine and the waters 
surrounding New England, but their mating and calving (and general 
wintering) areas are largely unknown (Hain et al., 1992; Hayes et al., 
2018). Recordings from Massachusetts Bay, New York Bight, and deep-
ocean areas have detected some level of fin whale singing from 
September through June (Watkins et al., 1987; Clark and Gagnon, 2002; 
Morano et al., 2012). These acoustic observations from both coastal and 
deep-ocean regions support the conclusion that male fin whales are 
broadly distributed throughout the western North Atlantic for most of 
the year (Hayes et al., 2019).
    Kraus et al. (2016) suggest that, compared to other baleen whale 
species, fin whales have a high multi-seasonal relative abundance in 
the RI/MA & MA WEAs and surrounding areas. Fin whales were observed in 
the MA WEA in spring and summer. This species was observed primarily in 
the offshore (southern) regions of the RI/MA & MA WEAs during spring 
and was found closer to shore (northern areas) during the summer months 
(Kraus et al., 2016). Calves were observed three times and feeding was 
observed nine times during the Kraus et al. (2016) study. Although fin 
whales were largely absent from visual surveys in the RI/MA and MA WEAs 
in the fall and winter months (Kraus et al. 2016), acoustic data 
indicated that this species was present in these areas during all 
months of the year.
    New England waters represent a major feeding ground for fin whales. 
The proposed project area would overlap spatially and temporally with 
approximately 11 percent of a relatively small fin whale feeding BIA 
(2,933 km\2\) offshore of Montauk Point, from March to October (Hain et 
al., 1992; LaBrecque et al., 2015). A separate larger year-round 
feeding BIA (18,015 km\2\) to the east in the southern Gulf of Maine 
does not overlap with the project area, and would thus not be impacted 
by project activities.
Minke Whale
    Minke whale occurrence is common and widespread in New England from 
spring to fall, although the species is largely absent in the winter 
(Hayes et al., 2021; Risch et al., 2013). Surveys conducted in the RI/
MA WEA from October 2011 through June 2015 reported 103 minke whale 
sightings within the area, predominantly in the spring, followed by 
summer and fall (Kraus et al., 2016).
    There are two minke whale feeding BIAs in the southern and 
southwestern section of the Gulf of Maine, including Georges Bank, the 
Great South Channel, Cape Cod Bay, Massachusetts Bay, Stellwagen Bank, 
Cape Anne, and Jeffreys Ledge from March through November, annually 
(LeBrecque et al., 2015). However, these BIAs do not overlap the 
project area, as they are located further east and north. The proposed 
project area likely serves as a migratory route for minke whales 
transiting between northern feeding grounds and southern breeding 
areas.
    Since January 2017, elevated minke whale mortalities detected along 
the

[[Page 79091]]

Atlantic coast from Maine through South Carolina resulted in the 
declaration of a UME. As of December 6, 2022, a total of 135 minke 
whales have stranded during this 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/2017-2021-minke-whale-unusual-mortality-event-along-atlantic-coast.
Seals
    Since June 2022, elevated numbers of harbor seal and gray seal 
mortalities have occurred across the southern and central coast of 
Maine. This event has been declared a UME. Preliminary testing of 
samples has found some harbor and gray seals positive for highly 
pathogenic avian influenza. While the UME is not occurring in the 
Revolution Wind project area, the populations affected by the UME are 
the same as those potentially affected by the project.
    The above event was preceded by a different UME, occurring from 
2018-2020 (closure of the 2018-2020 UME is pending). Beginning in July 
2018, elevated numbers of harbor seal and gray seal mortalities 
occurred across Maine, New Hampshire and Massachusetts. Additionally, 
stranded seals have shown clinical signs as far south as Virginia, 
although not in elevated numbers, therefore the UME investigation 
encompassed all seal strandings from Maine to Virginia. A total of 
3,152 reported strandings (of all species) occurred from July 1, 2018, 
through March 13, 2020. 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, 
which is pending closure. Information on this UME is available online 
at: www.fisheries.noaa.gov/new-england-mid-atlantic/marine-life-distress/2018-2020-pinniped-unusual-mortality-event-along.
Marine Mammal Hearing
    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Current data indicate that not all marine 
mammal species have equal hearing capabilities (e.g., Richardson et 
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect 
this, Southall et al. (2007) recommended that marine mammals be divided 
into functional hearing groups based on directly measured or estimated 
hearing ranges on the basis of available behavioral response data, 
audiograms derived using auditory evoked potential techniques, 
anatomical modeling, and other data. Note that no direct measurements 
of hearing ability have been successfully completed for mysticetes 
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibel (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-frequency cetaceans where the 
lower bound was deemed to be biologically implausible and the lower 
bound from Southall et al. (2007) retained. Marine mammal hearing 
groups and their associated hearing ranges are provided in Table 6.

                  Table 6--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
                                               Generalized hearing range
                Hearing group                              *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen whales).  7 Hz to 35 kHz.
Mid-frequency (MF) cetaceans (dolphins,        150 Hz to 160 kHz.
 toothed whales, beaked whales, bottlenose
 whales).
High-frequency (HF) cetaceans (true            275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 cephalorhynchid, Lagenorhynchus cruciger &
 L. australis).
Phocid pinnipeds (PW) (underwater) (true       50 Hz to 86 kHz.
 seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al., 2007) and PW pinniped (approximation).

    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt, 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information. 
Sixteen marine mammal species (14 cetacean species (6 mysticetes and 8 
odontocetes) and 2 pinniped species (both phocid seals)) have the 
reasonable potential to co-occur with the proposed project activities 
(Table 5).
    NMFS notes that in 2019, Southall et al. recommended new names for 
hearing groups that are widely recognized. However, this new hearing 
group classification does not change the weighting functions or 
acoustic thresholds (i.e., the weighting functions and thresholds in 
Southall et al. (2019) are identical to NMFS 2018 Revised Technical 
Guidance). When NMFS updates our Technical Guidance, we will be 
adopting the updated Southall et al. (2019) hearing group 
classification.

Potential Effects to 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

[[Page 79092]]

those impacts on individuals are likely to impact marine mammal species 
or stocks. General background information on marine mammal hearing was 
provided previously (see the Description of Marine Mammals in the Area 
of the Specified Activities section). Here, the potential effects of 
sound on marine mammals are discussed.
    Revolution Wind has requested authorization to take marine mammals 
incidental to construction activities in the Revolution Wind project 
area. In the ITA application, Revolution Wind presented analyses of 
potential impacts to marine mammals from use of acoustic and explosive 
sources. NMFS both carefully reviewed the information provided by 
Revolution Wind, as well as independently reviewed applicable 
scientific research and literature and other information, to evaluate 
the potential effects of Revolution Wind's activities on marine 
mammals, which are presented in this section.
    The proposed activities would result in placement of up to 81 
permanent foundations and two temporary cofferdams in the marine 
environment. Up to 13 UXO/MEC detonations may occur intermittently, 
only as necessary. There are a variety of effects to marine mammals, 
prey species, and habitat that could occur as a result of these 
actions.

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), and 
Urick (1983).
    Sound is a vibration that travels as an acoustic wave through a 
medium such as a gas, liquid or solid. Sound waves alternately compress 
and decompress the medium as the wave travels. These compressions and 
decompressions are detected as changes in pressure by aquatic life and 
man-made sound receptors such as hydrophones (underwater microphones). 
In water, sound waves radiate in a manner similar to ripples on the 
surface of a pond and may be either directed in a beam (narrow beam or 
directional sources) or sound beams may radiate in all directions 
(omnidirectional sources).
    Sound travels in water more efficiently than almost any other form 
of energy, making the use of acoustics ideal for the aquatic 
environment and its inhabitants. In seawater, sound travels at roughly 
1,500 meters per second (m/s). In -air, sound waves travel much more 
slowly, at about 340 m/s. However, the speed of sound can vary by a 
small amount based on characteristics of the transmission medium, such 
as water temperature and salinity.
    The basic components of a sound wave 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. The intensity (or amplitude) of sounds are 
measured in decibels (dB), which are a relative unit of measurement 
that is used to express the ratio of one value of a power or field to 
another. Decibels are measured on a logarithmic scale, so a small 
change in dB corresponds to large changes in sound pressure. For 
example, a 10-dB increase is a ten-fold increase in acoustic power. A 
20-dB increase is then a 100-fold increase in power and a 30-dB 
increase is a 1000-fold increase in power. However, a ten-fold increase 
in acoustic power does not mean that the sound is perceived as being 
ten times louder. Decibels are a relative unit comparing two pressures, 
therefore a reference pressure must always be indicated. For underwater 
sound, this is 1 microPascal ([mu]Pa). For in-air sound, the reference 
pressure is 20 microPascal ([mu]Pa). The amplitude of a sound can be 
presented in various ways; however, NMFS typically utilizes three 
metrics.
    Sound exposure level (SEL) represents the total energy in a stated 
frequency band over a stated time interval or event, and considers both 
amplitude and duration of exposure (represented as dB re 1 [mu]Pa\2\-
s). SEL is a cumulative metric; it can be accumulated over a single 
pulse (for pile driving this is often referred to as single-strike SEL; 
SELss), or calculated over periods containing multiple 
pulses (SELcum). Cumulative SEL represents the total energy 
accumulated by a receiver over a defined time window or during an 
event. The SEL metric is useful because it allows sound exposures of 
different durations to be related to one another in terms of total 
acoustic energy. The duration of a sound event and the number of 
pulses, however, should be specified as there is no accepted standard 
duration over which the summation of energy is measured. Sounds are 
typically classified by their spectral and temporal properties.
    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.
    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. Along with 
SEL, this metric is used in evaluating the potential for permanent 
threshold shift (PTS) and temporary threshold shift (TTS). It is also 
used to evaluate the potential for gastro-intestinal tract injury 
(Level A harassment) from explosives.
    For explosives, an impulse metric (Pa-s), which is the integral of 
a transient sound pressure over the duration of the pulse, is used to 
evaluate the potential for mortality (i.e., severe lung injury) and 
slight lung injury. These thresholds account for animal mass and depth.
    Sounds can be either impulsive or non-impulsive. 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 NMFS et 
al. (2018) and Southall et al. (2007, 2019) for an in-depth discussion 
of these concepts. 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 (American National Standards Institute (ANSI), 1986, 
2005; Harris, 1998; National Institute for Occupational Safety and 
Health (NIOSH), 1998; International Organization for Standardization 
(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

[[Page 79093]]

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. Impulsive sounds are 
typically intermittent in nature.
    Non-impulsive sounds can be tonal, narrowband, or broadband, brief 
or prolonged, and may be either continuous or intermittent (ANSI, 1995; 
NIOSH, 1998). Some of these non-impulsive sounds can be transient 
signals of short duration but without the essential properties of 
pulses (e.g., rapid rise time). Examples of non-impulsive sounds 
include those produced by vessels, aircraft, machinery operations such 
as drilling or dredging, vibratory pile driving, and active sonar 
systems.
    Sounds are also characterized by their temporal component. 
Continuous sounds are those whose sound pressure level remains above 
that of the ambient sound, with negligibly small fluctuations in level 
(NIOSH, 1998; ANSI, 2005), while intermittent sounds are defined as 
sounds with interrupted levels of low or no sound (NIOSH, 1998). NMFS 
identifies Level B harassment thresholds based on if a sound is 
continuous or intermittent.
    Even in the absence of sound from the specified activity, the 
underwater environment is typically loud due to ambient sound, which is 
defined as environmental background sound levels lacking a single 
source or point (Richardson et al., 1995). The sound level of a region 
is defined by the total acoustical energy being generated by known and 
unknown sources. These sources may include physical (e.g., wind and 
waves, earthquakes, ice, atmospheric sound), biological (e.g., sounds 
produced by marine mammals, fish, and invertebrates), and anthropogenic 
(e.g., vessels, dredging, construction) sound. A number of sources 
contribute to ambient sound, including wind and waves, which are a main 
source of naturally occurring ambient sound for frequencies between 200 
Hz and 50 kHz (International Council for Exploration of the Sea (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 comprises sounds produced by a number of natural and 
anthropogenic sources. Human-generated sound is a significant 
contributor to the acoustic environment in the project location.

Potential Effects of Underwater Sound on Marine Mammals

    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. Broadly, underwater sound from active acoustic sources 
can potentially result in one or more of the following: temporary or 
permanent hearing impairment, non-auditory physical or physiological 
effects, behavioral disturbance, stress, and masking (Richardson et 
al., 1995; Gordon et al., 2003; Nowacek et al., 2007; Southall et al., 
2007; G[ouml]tz et al., 2009). Potential effects from explosive sound 
sources can range in severity from behavioral disturbance or tactile 
perception to physical discomfort, slight injury of the internal organs 
and the auditory system, or mortality (Yelverton et al., 1973). The 
degree of effect is intrinsically related to the signal 
characteristics, received level, distance from the source, and duration 
of the sound exposure, in addition to the contextual factors of the 
receiver (e.g., behavioral state at time of exposure, age class, etc.). 
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 describe below the specific manifestations of 
acoustic effects that may occur based on the activities proposed by 
Revolution Wind.
    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 (at the greatest distance) 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 (closer to the receiving animal) corresponds 
with the area where the signal is audible to the animal and of 
sufficient intensity to elicit behavioral or physiological 
responsiveness. The 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.
    Potential effects from explosive 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).

[[Page 79094]]

    Below, we provide additional detail regarding potential impacts on 
marine mammals and their habitat from noise in general, as well as from 
the specific activities Revolution Wind plans to conduct, to the degree 
it is available (noting that there is limited information regarding the 
impacts of offshore wind construction on cetaceans).
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, expressed in decibels (NMFS, 2018). Threshold shifts can be 
permanent, in which case there is an irreversible increase in the 
threshold of audibility at a specified frequency or portion of an 
individual's hearing range, or temporary, in which there is reversible 
increase in the threshold of audibility at a specified frequency or 
portion of an individual's hearing range and the animal's hearing 
threshold would fully recover over time (Southall et al., 2019). 
Repeated sound exposure that leads to TTS could cause PTS.
    When PTS occurs, there can be physical damage to the sound 
receptors in the ear (i.e., tissue damage), whereas TTS represents 
primarily tissue fatigue and is reversible (Henderson et al., 2008). 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; Southall et al., 2019). 
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 a PTS 
onset; e.g., Kryter et al., 1966; Miller, 1974; Henderson et al., 
2008). This can also induce mild TTS (a 6 dB threshold shift 
approximates a TTS onset; e.g., Southall et al., 2019). Based on data 
from terrestrial mammals, a precautionary assumption is that the PTS 
thresholds, expressed in the unweighted peak sound pressure level 
metric (PK), for impulsive sounds (such as impact pile driving pulses) 
are at least 6 dB higher than the TTS thresholds and the weighted PTS 
cumulative sound exposure level thresholds are 15 (impulsive sound) to 
20 (non-impulsive sounds) dB higher than TTS cumulative sound exposure 
level thresholds (Southall et al., 2019). Given the higher level of 
sound or longer exposure duration necessary to cause PTS as compared 
with TTS, PTS is less likely to occur as a result of these activities, 
but it is possible and a small amount has been proposed for 
authorization for several species.
    TTS is the mildest form of hearing impairment that can occur during 
exposure to sound, with a TTS of 6 dB considered the minimum threshold 
shift clearly larger than any day-to-day or session-to-session 
variation in a subject's normal hearing ability (Schlundt et al., 2000; 
Finneran et al., 2000; Finneran et al., 2002).
    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. There is data on sound levels and durations 
necessary to elicit mild TTS for marine mammals but recovery is 
complicated to predict and dependent on multiple factors.
    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 six species of pinnipeds (northern elephant seal (Mirounga 
angustirostris), harbor seal, ring seal, spotted seal, bearded seal, 
and California sea lion (Zalophus californianus)) that were exposed to 
a limited number of sound sources (i.e., mostly tones and octave-band 
noise with limited number of exposure to impulsive sources such as 
seismic airguns or impact pile driving) in laboratory settings 
(Southall et al., 2019). There is currently 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. (2019), and NMFS (2018).
    Recent studies with captive odontocete species (bottlenose dolphin, 
harbor porpoise, beluga, and false killer whale) have observed 
increases in hearing threshold levels when individuals received a 
warning sound prior to exposure to a relatively loud sound (Nachtigall 
and Supin, 2013, 2015; Nachtigall et al., 2016a,b,c; Finneran, 2018; 
Nachtigall et al., 2018). These studies suggest that captive animals 
have a mechanism to reduce hearing sensitivity prior to impending loud 
sounds. Hearing change was observed to be frequency dependent and 
Finneran (2018) suggests hearing attenuation occurs within the cochlea 
or auditory nerve. Based on these observations on captive odontocetes, 
the authors suggest that wild animals may have a mechanism to self-
mitigate the impacts of noise exposure by dampening their hearing 
during prolonged exposures of loud sound, or if conditioned to 
anticipate intense sounds (Finneran, 2018; Nachtigall et al., 2018).
Behavioral Disturbance
    Behavioral responses to sound are highly variable and context-
specific. Many different variables can influence an animal's perception 
of and response to (nature and magnitude) an acoustic event. An 
animal's prior experience with a sound or sound source affects whether 
it is less likely (habituation) or more likely (sensitization) to 
respond to certain sounds in the future (animals can also be innately 
predisposed to respond to certain sounds in certain ways) (Southall et 
al., 2019). Related to the sound itself, the perceived nearness of the 
sound, bearing of the sound (approaching vs. retreating), the 
similarity of a sound to biologically relevant sounds in the animal's 
environment (i.e., calls of predators, prey, or conspecifics), and 
familiarity of the sound may affect the way an animal responds to the 
sound (Southall et al., 2007; DeRuiter et al., 2013). Individuals (of 
different age, gender, reproductive status, etc.) among most 
populations will have variable hearing capabilities, and differing 
behavioral sensitivities to sounds that will be affected by prior

[[Page 79095]]

conditioning, experience, and current activities of those individuals. 
Often, specific acoustic features of the sound and contextual variables 
(i.e., proximity, duration, or recurrence of the sound or the current 
behavior that the marine mammal is engaged in or its prior experience), 
as well as entirely separate factors such as the physical presence of a 
nearby vessel, may be more relevant to the animal's response than the 
received level alone. For example, Goldbogen et al. (2013b) 
demonstrated that individual behavioral state was critically important 
in determining response of blue whales to sonar, noting that some 
individuals engaged in deep (greater than 50 m) feeding behavior had 
greater dive responses than those in shallow feeding or non-feeding 
conditions. Some blue whales in the Goldbogen et al. (2013b) study that 
were engaged in shallow feeding behavior demonstrated no clear changes 
in diving or movement even when received levels were high (~160 dB re 
1[mu]Pa) for exposures to 3-4 kHz sonar signals, while others showed a 
clear response at exposures at lower received levels of sonar and 
pseudorandom noise.
    Studies by DeRuiter et al. (2012) indicate that variability of 
responses to acoustic stimuli depends not only on the species receiving 
the sound and the sound source, but also on the social, behavioral, or 
environmental contexts of exposure. Another study by DeRuiter et al. 
(2013) examined behavioral responses of Cuvier's beaked whales to MF 
sonar and found that whales responded strongly at low received levels 
(89-127 dB re 1[mu]Pa) by ceasing normal fluking and echolocation, 
swimming rapidly away, and extending both dive duration and subsequent 
non-foraging intervals when the sound source was 3.4-9.5 km away. 
Importantly, this study also showed that whales exposed to a similar 
range of received levels (78-106 dB re 1[mu]Pa) from distant sonar 
exercises (118 km away) did not elicit such responses, suggesting that 
context may moderate reactions. Thus, it is known that distance from 
the source can have an effect on behavioral response that is 
independent of the effect of received levels (e.g., DeRuiter et al., 
2013; Dunlop et al., 2017a; Dunlop et al., 2017b; Falcone et al., 2017; 
Dunlop et al., 2018; Southall et al., 2019a).
    Ellison et al. (2012) outlined an approach to assessing the effects 
of sound on marine mammals that incorporates contextual-based factors. 
The authors recommend considering not just the received level of sound, 
but also the activity the animal is engaged in at the time the sound is 
received, the nature and novelty of the sound (i.e., is this a new 
sound from the animal's perspective), and the distance between the 
sound source and the animal. They submit that this ``exposure 
context,'' as described, greatly influences the type of behavioral 
response exhibited by the animal. Forney et al. (2017) also point out 
that an apparent lack of response (e.g., no displacement or avoidance 
of a sound source) may not necessarily mean there is no cost to the 
individual or population, as some resources or habitats may be of such 
high value that animals may choose to stay, even when experiencing 
stress or hearing loss. Forney et al. (2017) recommend considering both 
the costs of remaining in an area of noise exposure such as TTS, PTS, 
or masking, which could lead to an increased risk of predation or other 
threats or a decreased capability to forage, and the costs of 
displacement, including potential increased risk of vessel strike, 
increased risks of predation or competition for resources, or decreased 
habitat suitable for foraging, resting, or socializing. This sort of 
contextual information is challenging to predict with accuracy for 
ongoing activities that occur over large spatial and temporal expanses. 
However, distance is one contextual factor for which data exist to 
quantitatively inform a take estimate, and the method for predicting 
Level B harassment in this rule does consider distance to the source. 
Other factors are often considered qualitatively in the analysis of the 
likely consequences of sound exposure, where supporting information is 
available.
    Friedlaender et al. (2016) provided the first integration of direct 
measures of prey distribution and density variables incorporated into 
across-individual analyses of behavior responses of blue whales to 
sonar, and demonstrated a five-fold increase in the ability to quantify 
variability in blue whale diving behavior. These results illustrate 
that responses evaluated without such measurements for foraging animals 
may be misleading, which again illustrates the context-dependent nature 
of the probability of response.
    Exposure of marine mammals to sound sources can result in, but is 
not limited to, no response or any of the following observable 
responses: Increased alertness; orientation or attraction to a sound 
source; vocal modifications; cessation of feeding; cessation of social 
interaction; alteration of movement or diving behavior; habitat 
abandonment (temporary or permanent); and, in severe cases, panic, 
flight, stampede, or stranding, potentially resulting in death 
(Southall et al., 2007). A review of marine mammal responses to 
anthropogenic sound was first conducted by Richardson (1995). More 
recent reviews (Nowacek et al., 2007; DeRuiter et al., 2012, 2013; 
Ellison et al., 2012; Gomez et al., 2016) address studies conducted 
since 1995 and focused on observations where the received sound level 
of the exposed marine mammal(s) was known or could be estimated. Gomez 
et al. (2016) conducted a review of the literature considering the 
contextual information of exposure in addition to received level and 
found that higher received levels were not always associated with more 
severe behavioral responses and vice versa. Southall et al. (2021) 
states that results demonstrate that some individuals of different 
species display clear yet varied responses, some of which have negative 
implications, while others appear to tolerate high levels, and that 
responses may not be fully predictable with simple acoustic exposure 
metrics (e.g., received sound level). Rather, the authors state that 
differences among species and individuals along with contextual aspects 
of exposure (e.g., behavioral state) appear to affect response 
probability. The following subsections provide examples of behavioral 
responses that provide an idea of the variability in behavioral 
responses that would be expected given the differential sensitivities 
of marine mammal species to sound and the wide range of potential 
acoustic sources to which a marine mammal may be exposed. Behavioral 
responses that could occur for a given sound exposure should be 
determined from the literature that is available for each species, or 
extrapolated from closely related species when no information exists, 
along with contextual factors.

Avoidance and Displacement

    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 
or humpback whales are known to change direction--deflecting from 
customary migratory paths--in order to avoid noise from airgun surveys 
(Malme et al., 1984; Dunlop et al., 2018). Avoidance is qualitatively 
different from the flight response, but also differs in the magnitude 
of the response (i.e., directed movement, rate of travel, etc.). 
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.,

[[Page 79096]]

2000; Morton and Symonds, 2002; Gailey et al., 2007; D[auml]hne et al., 
2013; Russel et al., 2016; Malme et al., 1984). 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; Forney et al., 2017). Avoidance of marine mammals during the 
construction of offshore wind facilities (specifically for impact pile 
driving) has been previously noted in the literature, with some 
significant variation in the effects. Most studies focused on harbor 
porpoises because it is one of the most common marine mammals in 
European waters (e.g., Tougaard et al., 2009; D[auml]hne et al., 2013; 
Thompson et al., 2013; Russell et al., 2016; Brandt et al., 2018).
    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 and 
other odontocete species are uncommon. Harbor porpoises and harbor 
seals are considered to be behaviorally sensitive species (e.g., 
Southall et al., 2007) and the effects of wind farm construction in 
Europe on these species has been well documented. These species have 
received particular attention in European waters due to their abundance 
in the North Sea (Hammond et al., 2002; Nachtsheim et al., 2021). A 
summary of the literature on documented effects of wind farm 
construction on harbor porpoises and harbor seals is described below.
    Brandt et al. (2016) summarized the effects of the construction of 
eight offshore wind projects within the German North Sea (i.e., Alpha 
Ventus, BARD Offshore I, Borkum West II, DanTysk, Global Tech I, 
Meerwind S[uuml]d/Ost, Nordsee Ost, and Riffgat) 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. Results of the analysis revealed significant declines in 
harbor porpoise detections during pile driving when compared to 24-48 
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. Similar results 
demonstrating the long-distance displacement of harbor porpoises (18-25 
km) and harbor seals (up to 40 km) during impact pile driving have also 
been observed during the construction at multiple other European wind 
farms (Lucke et al., 2012; D[auml]hne et al., 2013; Tougaard et al., 
2009; Haelters et al., 2015; Bailey et al., 2010).
    While harbor porpoises and seals tend to move away from wind farm 
construction activities, the duration of displacement has been 
documented to be relatively temporary. In two studies at Horns Rev II 
using impact pile driving, harbor porpoises returned within 1-2 days 
following cessation of pile driving (Tougaard et al., 2009, Brandt et 
al., 2011). Similar recovery periods have been noted for harbor seals 
off of England during the construction of four wind farms (Carroll et 
al., 2010; Hamre et al., 2011; Hastie et al., 2015; Russell et al., 
2016; Brasseur et al., 2010). In some cases, an increase in harbor 
porpoise activity has been documented inside wind farm areas following 
construction (e.g., Lindeboom et al., 2011). Other studies have noted 
longer-term impacts after impact pile driving. Near Dogger Bank in 
Germany, harbor porpoises continued to avoid the area for over two 
years after construction began (Gilles et al. 2009). Approximately ten 
years after construction of the Nysted wind farm, harbor porpoise 
abundance had not recovered to the original levels previously observed, 
although echolocation activity was noted to have been increasing when 
compared to the previous monitoring period (Teilmann and Carstensen, 
2012). However, overall, there are no indications of a population 
decline of harbor porpoises in European waters (e.g., Brandt et al., 
2016). Notably, where significant differences in displacement and 
return rates have been identified for these species, the occurrence of 
secondary project-specific influences such as use of mitigation 
measures (e.g., bubble curtains, acoustic deterrent devices (ADDs)) or 
the manner in which species use the habitat in the project area are 
likely the driving factors of this variation.
    NMFS notes the aforementioned studies from Europe involve pile 
driving of much smaller piles than Revolution Wind proposes to install 
and, therefore, we anticipate noise levels from impact pile driving to 
be louder. For this reason, we anticipate that the greater distances of 
displacement observed in harbor porpoises and harbor seals documented 
in Europe are more likely to occur off of Rhode Island. However, we do 
not anticipate any greater severity of response or population level 
consequences, similar to European findings. In many cases, harbor 
porpoises and harbor seals are resident to the areas where European 
wind farms have been constructed. However, harbor porpoises and harbor 
seals are seasonally present in the project area, predominantly 
occurring in winter, when impact pile driving would not occur. In 
summary, we anticipate that harbor porpoises and harbor seals would 
likely respond to pile driving by moving several kilometers away from 
the source; however, this impact would be temporary and would not 
impact any critical behaviors such as foraging or reproduction.
    As noted previously, 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 would occur in other marine mammal species.
    Avoidance has been documented for other marine mammal species in 
response to playbacks. DeRuiter et al. (2013) noted that distance from 
a sound source may moderate marine mammal reactions in their study of 
Cuvier's beaked whales, which showed the whales swimming rapidly and 
silently away when a sonar signal was 3.4-9.5 km away, while showing no 
such reaction to the same signal when the signal was 118 km away, even 
though the received levels were similar. Tyack and Clark (1983) 
conducted playback studies of Surveillance Towed Array Sensor System 
(SURTASS) low frequency active (LFA) sonar in a gray whale migratory 
corridor off California. Similar to North Atlantic right whales, gray 
whales migrate close to shore (approximately +2 kms) and are low 
frequency hearing specialists. The LFA sonar source was placed within 
the gray whale migratory corridor (approximately 2 km offshore) and 
offshore of most, but not all, migrating whales (approximately 4 km 
offshore). These locations influenced received levels and distance to 
the source. For the inshore playbacks, not unexpectedly, when the 
source level of the playback was louder (i.e., the louder

[[Page 79097]]

the received level), whales avoided the source at greater distances. 
Specifically, when the source level was 170 dB rms and 178 dB rms, 
whales avoided the inshore source at ranges of several hundred meters, 
similar to avoidance responses reported by Malme et al. (1983, 1984). 
Whales exposed to source levels of 185 dB rms demonstrated avoidance 
levels at ranges of +1 km. While there was observed deflection from 
course, in no case did a whale abandon its migratory behavior.
    One consequence of behavioral avoidance results in the altered 
energetic expenditure of marine mammals because energy is required to 
move and avoid surface vessels or the sound field associated with e.g., 
active sonar (Frid and Dill, 2002). Most animals can avoid that 
energetic cost by swimming away at slow speeds or speeds that minimize 
the cost of transport (Miksis-Olds, 2006), as has been demonstrated in 
Florida manatees (Miksis-Olds, 2006). Those energetic costs increase, 
however, when animals shift from a resting state, which is designed to 
conserve an animal's energy, to an active state that consumes energy 
the animal would have conserved had it not been disturbed. Marine 
mammals that have been disturbed by anthropogenic noise and vessel 
approaches are commonly reported to shift from resting to active 
behavioral states, which would imply that they incur an energy cost.
    Forney et al. (2017) detailed the potential effects of noise on 
marine mammal populations with high site fidelity, including 
displacement and auditory masking, noting that a lack of observed 
response does not imply absence of fitness costs and that apparent 
tolerance of disturbance may have population-level impacts that are 
less obvious and difficult to document. Avoidance of overlap between 
disturbing noise and areas and/or times of particular importance for 
sensitive species may be critical to avoiding population-level impacts 
because (particularly for animals with high site fidelity) there may be 
a strong motivation to remain in the area despite negative impacts. 
Forney et al. (2017) stated that, for these animals, remaining in a 
disturbed area may reflect a lack of alternatives rather than a lack of 
effects.

Flight Response

    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 exists, although observations of 
flight responses to the presence of predators have occurred (Connor and 
Heithaus, 1996; Frid and Dill, 2002). 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. 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, beaked 
whale strandings (Cox et al., 2006; D'Amico et al., 2009). Flight 
responses of marine mammals have been documented in response to mobile 
high intensity active sonar (e.g., Tyack et al., 2011; DeRuiter et al., 
2013; Wensveen et al., 2019), and more severe responses have been 
documented when sources are moving towards an animal or when they are 
surprised by unpredictable exposures (Watkins, 1986; Falcone et al., 
2017). Generally speaking, however, marine mammals would be expected to 
be less likely to respond with a flight response to either stationery 
pile driving (which they can sense is stationery and predictable) or 
significantly lower-level HRG surveys, unless they are within the area 
ensonified above behavioral harassment thresholds at the moment the 
source is turned on (Watkins, 1986; Falcone et al., 2017). A flight 
response may also be possible in response to UXO/MEC detonation; 
however, given a detonation is instantaneous, only one detonation would 
occur on a given day, only 13 detonations may occur over 5 years, and 
the proposed mitigation and monitoring would result in any animals 
being far from the detonation (i.e., the clearance zone extends 10 km 
from the UXO/MEC location), any flight response would be spatially and 
temporally limited.

Alteration of Diving and Foraging

    Changes in dive behavior in response to noise exposure can vary 
widely. They may consist of increased or decreased dive times and 
surface intervals as well as changes in the rates of ascent and descent 
during a dive (e.g., Frankel and Clark, 2000; Costa et al., 2003; Ng 
and Leung, 2003; Nowacek et al., 2004; Goldbogen et al., 2013a, 2013b). 
Variations in dive behavior may reflect interruptions in biologically 
significant activities (e.g., foraging) or they may be of little 
biological significance. Variations in dive behavior may also expose an 
animal to potentially harmful conditions (e.g., increasing the chance 
of ship-strike) or may serve as an avoidance response that enhances 
survivorship. The impact of a variation in diving 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.
    Nowacek et al. (2004) reported disruptions of dive behaviors in 
foraging North Atlantic right whales when exposed to an alerting 
stimulus, an action, they noted, that could lead to an increased 
likelihood of ship strike. The alerting stimulus was in the form of an 
18-minute exposure that included three 2-minute signals played three 
times sequentially. This stimulus was designed with the purpose of 
providing signals distinct to background noise that serve as 
localization cues. However, the whales did not respond to playbacks of 
either right whale social sounds or vessel noise (both of which were 
signal types included in the playback experiment), highlighting the 
importance of the sound characteristics in producing a behavioral 
reaction. The alerting stimulus signals were relatively brief in 
duration, similar to the proposed Revolution Wind impact pile driving 
strikes, UXO detonation, and some HRG acoustic sources. Although source 
levels for Revolution Wind's activities may exceed the source level of 
the alerting stimulus, proposed mitigation strategies (further 
described in the Proposed Mitigation section) would reduce the severity 
of any responses to the activities. Converse to North Atlantic right 
whale behavior, Indo-Pacific humpback dolphins have been observed 
diving for longer periods of time in areas where vessels were present 
and/or approaching (Ng and Leung, 2003). In both of these studies, the 
influence of the sound exposure cannot be decoupled from the physical 
presence of a surface vessel, thus complicating interpretations of the 
relative contribution of each stimulus to the response. Indeed, the 
presence of surface vessels, their approach, and speed of approach, 
seemed to be significant factors in the response of the Indo-Pacific 
humpback dolphins (Ng and Leung, 2003). Low-frequency signals of the 
Acoustic Thermometry of Ocean Climate (ATOC) sound source were not 
found to affect dive times of humpback whales in Hawaiian waters 
(Frankel and Clark, 2000) or to overtly affect elephant seal dives 
(Costa et al., 2003). They did, however, produce subtle effects that 
varied in direction and degree among the individual elephant seals, 
illustrating the equivocal nature of behavioral effects and

[[Page 79098]]

consequent difficulty in defining and predicting them.
    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., 2006a; Yazvenko et al., 
2007; Southall et al., 2019b). 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 (Goldbogen et al., 
2013b; Farmer et al., 2018; Pirotta et al., 2018; Southall et al., 
2019; Pirotta et al., 2021).
    Impacts on marine mammal foraging rates from noise exposure have 
been documented, though there is little data regarding the impacts of 
offshore turbine construction specifically. Several broader examples 
follow, and it is reasonable to expect that exposure to noise produced 
during the 5-years the proposed rule would be effective could have 
similar impacts.
    Visual tracking, passive acoustic monitoring, and movement 
recording tags were used to quantify sperm whale behavior prior to, 
during, and following exposure to air gun arrays at received levels in 
the range 140-160 dB at distances of 7-13 km, following a phase-in of 
sound intensity and full array exposures at 1-13 km (Madsen et al., 
2006a; Miller et al., 2009). Sperm whales did not exhibit horizontal 
avoidance behavior at the surface. However, foraging behavior may have 
been affected. The sperm whales exhibited 19 percent less vocal (buzz) 
rate during full exposure relative to post exposure, and the whale that 
was approached most closely had an extended resting period and did not 
resume foraging until the air guns had ceased firing. The remaining 
whales continued to execute foraging dives throughout exposure; 
however, swimming movements during foraging dives were six percent 
lower during exposure than control periods (Miller et al., 2009). 
Miller et al. (2009) noted that more data are required to understand 
whether the differences were due to exposure or natural variation in 
sperm whale behavior. We note that the water depths in the project area 
preclude deep foraging dives for any marine mammal species and sperm 
whales are not expected to be foraging in the area. However, some 
temporary disruption to marine mammals that may be foraging in the 
project area is likely to occur.
    Balaenopterid whales (fin and blue whales) exposed to moderate low-
frequency active sonar (signals similar to the ATOC sound source) 
demonstrated no variation in foraging activity (Croll et al., 2001), 
whereas five out of six North Atlantic right whales exposed to the 
alerting stimulus (described previously) interrupted their foraging 
dives (Nowacek et al., 2004). Although the received SPLs were similar 
in the two studies, the frequency, duration, and temporal pattern of 
signal presentation were different. These factors, as well as 
differences in species sensitivity, are likely contributing factors to 
the differential response. Source levels generated during Revolution 
Wind's activities would generally meet or exceed the source levels of 
the signals described by Nowacek et al. (2004) (173 dB rms at 1 m) and 
Croll et al. (2001) (155 dB rms increased at 10dB intervals) and noise 
generated by Revolution Wind's activities would overlap in frequency 
with the described signals. Blue whales exposed to mid-frequency sonar 
in the Southern California Bight were less likely to produce low-
frequency calls usually associated with feeding behavior (Melc[oacute]n 
et al., 2012). However, Melc[oacute]n et al. (2012) were unable to 
determine if suppression of low frequency calls reflected a change in 
their feeding performance or abandonment of foraging behavior and 
indicated that implications of the documented responses are unknown. 
Further, it is not known whether the lower rates of calling actually 
indicated a reduction in feeding behavior or social contact since the 
study used data from remotely deployed, passive acoustic monitoring 
buoys. Results from the 2010-2011 field season of a behavioral response 
study in Southern California waters indicated that, in some cases and 
at low received levels, tagged blue whales responded to mid-frequency 
sonar but that those responses were mild and there was a quick return 
to their baseline activity (Southall et al., 2011, 2012, 2019).
    Information on or estimates of the energetic requirements of the 
individuals and the relationship between prey availability, foraging 
effort and success, and the life history stage of the animal will help 
better inform a determination of whether foraging disruptions incur 
fitness consequences. Foraging strategies may impact foraging 
efficiency, such as by reducing foraging effort and increasing success 
in prey detection and capture, in turn promoting fitness and allowing 
individuals to better compensate for foraging disruptions. Surface 
feeding blue whales did not show a change in behavior in response to 
mid-frequency simulated and real sonar sources with received levels 
between 90 and 179 dB re 1 [micro]Pa, but deep feeding and non-feeding 
whales showed temporary reactions, including cessation of feeding, 
reduced initiation of deep foraging dives, generalized avoidance 
responses, and changes to dive behavior (DeRuiter et al., 2017; 
Goldbogen et al., 2013b; Sivle et al., 2015). Goldbogen et al. (2013b) 
indicate that disruption of feeding and displacement could impact 
individual fitness and health. However, for this to be true, we would 
have to assume that an individual whale could not compensate for this 
lost feeding opportunity by either immediately feeding at another 
location, by feeding shortly after cessation of acoustic exposure, or 
by feeding at a later time. There is no indication this is the case, 
particularly since unconsumed prey would likely still be available in 
the environment in most cases following the cessation of acoustic 
exposure.
    Similarly, while the rates of foraging lunges decrease in humpback 
whales due to sonar exposure, there was variability in the response 
across individuals, with one animal ceasing to forage completely and 
another animal starting to forage during the exposure (Sivle et al., 
2016). In addition, almost half of the animals that demonstrated 
avoidance were foraging before the exposure, but the others were not; 
the animals that avoided while not feeding responded at a slightly 
lower received level and greater distance than those that were feeding 
(Wensveen et al., 2017). These findings indicate the behavioral state 
of the animal and foraging strategies play a role in the type and 
severity of a behavioral response. For example, when the prey field was 
mapped and used as a covariate in examining how behavioral state of 
blue whales is influenced by mid-frequency sound, the response in blue 
whale deep-feeding behavior was even more apparent, reinforcing the 
need for contextual variables to be included when assessing behavioral 
responses (Friedlaender et al., 2016).

Breathing

    Respiration naturally varies with different behaviors and 
variations in

[[Page 79099]]

respiration 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. Mean exhalation rates of gray whales at rest and while diving 
were found to be unaffected by seismic surveys conducted adjacent to 
the whale feeding grounds (Gailey et al., 2007). Studies with captive 
harbor porpoises show increased respiration rates upon introduction of 
acoustic alarms (Kastelein et al., 2001; Kastelein et al., 2006a) and 
emissions for underwater data transmission (Kastelein et al., 2005). 
However, exposure to the same acoustic alarm of a striped dolphin under 
the same conditions did not elicit a response (Kastelein et al., 
2006a), again highlighting the importance of understanding species 
differences in the tolerance of underwater noise when determining the 
potential for impacts resulting from anthropogenic sound exposure.

Vocalizations (Also see the Auditory Masking Section)

    Marine mammals vocalize for different purposes and across multiple 
modes, such as whistling, production of echolocation clicks, calling, 
and singing. Changes in vocalization behavior in response to 
anthropogenic noise can occur for any of these modes and may result 
directly from increased vigilance (also see the Potential Effects of 
Behavioral Disturbance on Marine Mammal Fitness section) or a startle 
response, or from a need to compete with an increase in background 
noise (see Erbe et al., 2016 review on communication masking), the 
latter of which is described more in the Auditory Masking section 
below.
    For example, in the presence of potentially masking signals, 
humpback whales and killer whales have been observed to increase the 
length of their vocalizations (Miller et al., 2000; Fristrup et al., 
2003; Foote et al., 2004) and blue increased song production (Di Iorio 
and Clark, 2010), 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 or reduce sound production 
during production of aversive signals (Bowles et al., 1994; Thode et 
al., 2020; Cerchio et al., 2014; McDonald et al., 1995).

Orientation

    A shift in an animal's resting state or an attentional change via 
an orienting response represent behaviors that would be considered mild 
disruptions if occurring alone. As previously mentioned, the responses 
may co-occur with other behaviors; for instance, an animal may 
initially orient toward a sound source, and then move away from it. 
Thus, any orienting response should be considered in context of other 
reactions that may occur.

Habituation and Sensitization

    Habituation can occur when an animal's response to a stimulus wanes 
with repeated exposure, usually in the absence of unpleasant associated 
events (Wartzok et al., 2003). Animals are most likely to habituate to 
sounds that are predictable and unvarying. It is important to note that 
habituation is appropriately considered as a ``progressive reduction in 
response to stimuli that are perceived as neither aversive nor 
beneficial,'' rather than as, more generally, moderation in response to 
human disturbance having a neutral or positive outcome (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. Both habituation and 
sensitization require an ongoing learning process. 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; U.S. National Research 
Council (NRC), 2003; Wartzok et al., 2003; Southall et al., 2019b). 
Controlled experiments with captive marine mammals have shown 
pronounced behavioral reactions, including avoidance of loud sound 
sources (e.g., Ridgway et al., 1997; Finneran et al., 2003; Houser et 
al., 2013a,b; Kastelein et al., 2018). 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; Tougaard et al., 2009; Brandt et al., 2011, Brandt et al., 
2012, D[auml]hne et al., 2013; Brandt et al., 2014; Russell et al., 
2016; Brandt et al., 2018). 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 
potential importance of frequency output in relation to the species' 
hearing sensitivity.
Stress Response
    An animal's perception of a threat may be sufficient to trigger 
stress responses consisting of some combination of behavioral 
responses, autonomic nervous system responses, neuroendocrine 
responses, or immune responses (e.g., Seyle, 1950; Moberg, 2000). In 
many cases, an animal's first and sometimes most economical (in terms 
of energetic costs) response is behavioral avoidance of the potential 
stressor. Autonomic nervous system responses to stress typically 
involve changes in heart rate, blood pressure, and gastrointestinal 
activity. These responses have a relatively short duration and may or 
may not have a significant long-term effect on an animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha, 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well studied through 
controlled experiments, and for both laboratory and free-ranging 
animals (e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et 
al., 2003; Krausman et al., 2004; Lankford et al., 2005). Stress

[[Page 79100]]

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., Lusseau and Bejder, 2007; 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. Lusseau and Bejder (2007) present data 
from three long-term studies illustrating the connections between 
disturbance from whale-watching boats and population-level effects in 
cetaceans. In Shark Bay, Australia, the abundance of bottlenose 
dolphins was compared within adjacent control and tourism sites over 
three consecutive 4.5-year periods of increasing tourism levels. 
Between the second and third time periods, in which tourism doubled, 
dolphin abundance decreased by 15 percent in the tourism area and did 
not change significantly in the control area. In Fiordland, New 
Zealand, two populations (Milford and Doubtful Sounds) of bottlenose 
dolphins with tourism levels that differed by a factor of seven were 
observed and significant increases in traveling time and decreases in 
resting time were documented for both. Consistent short-term avoidance 
strategies were observed in response to tour boats until a threshold of 
disturbance was reached (average 68 minutes between interactions), 
after which the response switched to a longer-term habitat displacement 
strategy. For one population, tourism only occurred in a part of the 
home range. However, tourism occurred throughout the home range of the 
Doubtful Sound population, and once boat traffic increased beyond the 
68-minute threshold (resulting in abandonment of their home range/
preferred habitat), reproductive success drastically decreased 
(increased stillbirths) and abundance decreased significantly (from 67 
to 56 individuals in a short period).
    These and other studies lead to a reasonable expectation that some 
marine mammals would 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, 2017).
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, or 
navigation) (Richardson et al., 1995; Erbe and Farmer, 2000; Tyack, 
2000; 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, pile driving) 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. 
Masking these acoustic signals can disturb the behavior of individual 
animals, groups of animals, or entire populations. Masking can lead to 
behavioral changes including vocal changes (e.g., Lombard effect, 
increasing amplitude, or changing frequency), cessation of foraging or 
lost foraging opportunities, and leaving an area, for both signalers 
and receivers, in an attempt to compensate for noise levels (Erbe et 
al., 2016) or because sounds that would typically have triggered a 
behavior were not detected. In humans, significant masking of tonal 
signals occurs as a result of exposure to noise in a narrow band of 
similar frequencies. As the sound level increases, though, the 
detection of frequencies above those of the masking stimulus decreases 
also. This principle is expected to apply to marine mammals as well 
because of common biomechanical cochlear properties across taxa.
    Therefore, when the coincident (masking) sound is man-made, it may 
be considered harassment when disrupting or altering critical 
behaviors. It is important to distinguish TTS and PTS, which persist 
after the sound exposure, from masking, which only occurs during the 
sound exposure. Because masking (without resulting in threshold shift) 
is not associated with abnormal physiological function, it is not 
considered a physiological effect, but rather a potential behavioral 
effect.
    The frequency range of the potentially masking sound is important 
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation 
sounds produced by odontocetes but are more likely to affect detection 
of mysticete communication calls and other potentially important 
natural sounds such as those produced by surf and some prey species. 
The masking of communication signals by anthropogenic noise may be 
considered as a reduction in the communication space of animals (e.g., 
Clark et al., 2009; Matthews et al., 2016) and may result in energetic 
or other costs as animals change their vocalization behavior (e.g., 
Miller et al., 2000; Foote et al., 2004; Parks et al., 2007; Di Iorio 
and Clark, 2009; Holt et al., 2009). Masking can be reduced in 
situations where the signal and noise come from different directions 
(Richardson et al., 1995), through amplitude modulation of the signal, 
or through other compensatory behaviors (Houser and Moore, 2014). 
Masking can be tested directly in captive species (e.g., Erbe, 2008), 
but in wild populations it must be either modeled or inferred from 
evidence of masking compensation. There are few studies addressing 
real-world masking sounds likely to be experienced by marine mammals in 
the wild (e.g., Branstetter et al., 2013; Cholewiak et al., 2018).
    The echolocation calls of toothed whales are subject to masking by 
high-frequency sound. Studies on captive odontocetes by Au et al. 
(1974, 1985, 1993) indicate that some species may use various processes 
to reduce masking effects (e.g., adjustments in echolocation call 
intensity or frequency as a function of background noise conditions). 
There is also evidence that the directional hearing abilities of 
odontocetes are useful in reducing masking at the high-frequencies 
these cetaceans use to echolocate, but not at the low-to-moderate 
frequencies they use to communicate (Zaitseva et al., 1980). A study by 
Nachtigall and Supin (2008) showed that false killer whales adjust 
their hearing to compensate for ambient sounds and the intensity of 
returning echolocation signals.
    Impacts on signal detection, measured by masked detection 
thresholds, are not the only important factors to address when 
considering the potential effects of masking. As marine mammals use 
sound to recognize conspecifics, prey, predators, or other biologically 
significant sources (Branstetter et al., 2016), it is also important to 
understand the impacts of masked recognition thresholds (often called 
``informational masking''). Branstetter et al., 2016 measured masked 
recognition thresholds for whistle-like sounds of bottlenose dolphins 
and observed that

[[Page 79101]]

they are approximately 4 dB above detection thresholds (energetic 
masking) for the same signals. Reduced ability to recognize a 
conspecific call or the acoustic signature of a predator could have 
severe negative impacts. Branstetter et al., 2016 observed that if 
``quality communication'' is set at 90 percent recognition the output 
of communication space models (which are based on 50 percent detection) 
would likely result in a significant decrease in communication range.
    As marine mammals use sound to recognize predators (Allen et al., 
2014; Cummings and Thompson, 1971; Cur[eacute] et al., 2015; Fish and 
Vania, 1971), the presence of masking noise may also prevent marine 
mammals from responding to acoustic cues produced by their predators, 
particularly if it occurs in the same frequency band. For example, 
harbor seals that reside in the coastal waters off British Columbia are 
frequently targeted by mammal-eating killer whales. The seals 
acoustically discriminate between the calls of mammal-eating and fish-
eating killer whales (Deecke et al., 2002), a capability that should 
increase survivorship while reducing the energy required to attend to 
all killer whale calls. Similarly, sperm whales (Cur[eacute] et al., 
2016; Isojunno et al., 2016), long-finned pilot whales (Visser et al., 
2016), and humpback whales (Cur[eacute] et al., 2015) changed their 
behavior in response to killer whale vocalization playbacks; these 
findings indicate that some recognition of predator cues could be 
missed if the killer whale vocalizations were masked. The potential 
effects of masked predator acoustic cues depends on the duration of the 
masking noise and the likelihood of a marine mammal encountering a 
predator during the time that detection and recognition of predator 
cues are impeded.
    Redundancy and context can also facilitate detection of weak 
signals. These phenomena may help marine mammals detect weak sounds in 
the presence of natural or manmade noise. Most masking studies in 
marine mammals present the test signal and the masking noise from the 
same direction. The dominant background noise may be highly directional 
if it comes from a particular anthropogenic source such as a ship or 
industrial site. Directional hearing may significantly reduce the 
masking effects of these sounds by improving the effective signal-to-
noise ratio.
    Masking affects both senders and receivers of acoustic signals and, 
at higher levels and longer duration, 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; Cholewiak et al., 
2018). All anthropogenic sound sources, but especially chronic and 
lower-frequency signals (e.g., from commercial vessel traffic), 
contribute to elevated ambient sound levels, thus intensifying masking.
    In addition to making it more difficult for animals to perceive and 
recognize acoustic cues in their environment, anthropogenic sound 
presents separate challenges for animals that are vocalizing. When they 
vocalize, animals are aware of environmental conditions that affect the 
``active space'' (or communication space) of their vocalizations, which 
is the maximum area within which their vocalizations can be detected 
before it drops to the level of ambient noise (Brenowitz, 2004; Brumm 
et al., 2004; Lohr et al., 2003). Animals are also aware of 
environmental conditions that affect whether listeners can discriminate 
and recognize their vocalizations from other sounds, which is more 
important than simply detecting that a vocalization is occurring 
(Brenowitz, 1982; Brumm et al., 2004; Dooling, 2004; Marten and Marler, 
1977; Patricelli et al., 2006). Most species that vocalize have evolved 
with an ability to make adjustments to their vocalizations to increase 
the signal-to-noise ratio, active space, and recognizability/
distinguishability of their vocalizations in the face of temporary 
changes in background noise (Brumm et al., 2004; Patricelli et al., 
2006). Vocalizing animals can make adjustments to vocalization 
characteristics such as the frequency structure, amplitude, temporal 
structure, and temporal delivery (repetition rate), or ceasing to 
vocalize.
    Many animals will combine several of these strategies to compensate 
for high levels of background noise. Anthropogenic sounds that reduce 
the signal-to-noise ratio of animal vocalizations, increase the masked 
auditory thresholds of animals listening for such vocalizations, or 
reduce the active space of an animal's vocalizations impair 
communication between animals. Most animals that vocalize have evolved 
strategies to compensate for the effects of short-term or temporary 
increases in background or ambient noise on their songs or calls. 
Although the fitness consequences of these vocal adjustments are not 
directly known in all instances, like most other trade-offs animals 
must make, some of these strategies probably come at a cost (Patricelli 
et al., 2006; Noren et al., 2017; Noren et al., 2020). Shifting songs 
and calls to higher frequencies may also impose energetic costs 
(Lambrechts, 1996).
    Marine mammals are also known to make vocal changes in response to 
anthropogenic noise. In cetaceans, vocalization changes have been 
reported from exposure to anthropogenic noise sources such as sonar, 
vessel noise, and seismic surveying (see the following for examples: 
Gordon et al., 2003; Di Iorio and Clark, 2010; Hatch et al., 2012; Holt 
et al., 2008; Holt et al., 2011; Lesage et al., 1999; McDonald et al., 
2009; Parks et al., 2007; Risch et al., 2012; Rolland et al., 2012), as 
well as changes in the natural acoustic environment (Dunlop et al., 
2014). Vocal changes can be temporary, or can be persistent. For 
example, model simulation suggests that the increase in starting 
frequency for the North Atlantic right whale upcall over the last 50 
years resulted in increased detection ranges between right whales. The 
frequency shift, coupled with an increase in call intensity by 20 dB, 
led to a call detectability range of less than 3 km to over 9 km 
(Tennessen and Parks, 2016). Holt et al. (2008) measured killer whale 
call source levels and background noise levels in the one to 40 kHz 
band and reported that the whales increased their call source levels by 
one dB SPL for every one dB SPL increase in background noise level. 
Similarly, another study on St. Lawrence River belugas reported a 
similar rate of increase in vocalization activity in response to 
passing vessels (Scheifele et al., 2005). Di Iorio and Clark (2010) 
showed that blue whale calling rates vary in association with seismic 
sparker survey activity, with whales calling more on days with surveys 
than on days without surveys. They suggested that the whales called 
more during seismic survey periods as a way to compensate for the 
elevated noise conditions.
    In some cases, these vocal changes may have fitness consequences, 
such as an increase in metabolic rates and oxygen consumption, as 
observed in bottlenose dolphins when increasing their call amplitude 
(Holt et al., 2015). A switch from vocal communication to physical, 
surface-generated sounds such as pectoral fin slapping or breaching was 
observed for humpback whales in the presence of increasing natural 
background noise levels, indicating that adaptations to masking may 
also move beyond vocal modifications (Dunlop et al., 2010).
    While these changes all represent possible tactics by the sound-
producing

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animal to reduce the impact of masking, the receiving animal can also 
reduce masking by using active listening strategies such as orienting 
to the sound source, moving to a quieter location, or reducing self-
noise from hydrodynamic flow by remaining still. The temporal structure 
of noise (e.g., amplitude modulation) may also provide a considerable 
release from masking through co-modulation masking release (a reduction 
of masking that occurs when broadband noise, with a frequency spectrum 
wider than an animal's auditory filter bandwidth at the frequency of 
interest, is amplitude modulated) (Branstetter and Finneran, 2008; 
Branstetter et al., 2013). Signal type (e.g., whistles, burst-pulse, 
sonar clicks) and spectral characteristics (e.g., frequency modulated 
with harmonics) may further influence masked detection thresholds 
(Branstetter et al., 2016; Cunningham et al., 2014).
    Masking is more likely to occur in the presence of broadband, 
relatively continuous noise sources such as vessels. Several studies 
have shown decreases in marine mammal communication space and changes 
in behavior as a result of the presence of vessel noise. For example, 
right whales were 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) as well as increasing the 
amplitude (intensity) of their calls (Parks, 2009; Parks et al., 2011). 
Clark et al. (2009) observed that right whales' communication space 
decreased by up to 84 percent in the presence of vessels. Cholewiak et 
al. (2018) also observed loss in communication space in Stellwagen 
National Marine Sanctuary for North Atlantic right whales, fin whales, 
and humpback whales with increased ambient noise and shipping noise. 
Although humpback whales off Australia did not change the frequency or 
duration of their vocalizations in the presence of ship noise, their 
source levels were lower than expected based on source level changes to 
wind noise, potentially indicating some signal masking (Dunlop, 2016). 
Multiple delphinid species have also been shown to increase the minimum 
or maximum frequencies of their whistles in the presence of 
anthropogenic noise and reduced communication space (for examples see: 
Holt et al., 2008; Holt et al., 2011; Gervaise et al., 2012; Williams 
et al., 2013; Hermannsen et al., 2014; Papale et al., 2015; Liu et al., 
2017). While masking impacts are not a concern from lower intensity, 
higher frequency HRG surveys, some degree of masking would be expected 
in the vicinity of turbine pile driving and concentrated support vessel 
operation. However, pile driving is an intermittent sound and would not 
be continuous throughout a day.

Potential Effects of Behavioral Disturbance on Marine Mammal Fitness

    The different ways that marine mammals respond to sound are 
sometimes indicators of the ultimate effect that exposure to a given 
stimulus will have on the well-being (survival, reproduction, etc.) of 
an animal. There is little quantitative marine mammal data relating the 
exposure of marine mammals from sound to effects on reproduction or 
survival, though data exists for terrestrial species to which we can 
draw comparisons for marine mammals. Several authors have reported that 
disturbance stimuli may cause animals to abandon nesting and foraging 
sites (Sutherland and Crockford, 1993); may cause animals to increase 
their activity levels and suffer premature deaths or reduced 
reproductive success when their energy expenditures exceed their energy 
budgets (Daan et al., 1996; Feare, 1976; Mullner et al., 2004); or may 
cause animals to experience higher predation rates when they adopt 
risk-prone foraging or migratory strategies (Frid and Dill, 2002). Each 
of these studies addressed the consequences of animals shifting from 
one behavioral state (e.g., resting or foraging) to another behavioral 
state (e.g., avoidance or escape behavior) because of human disturbance 
or disturbance stimuli.
    Attention is the cognitive process of selectively concentrating on 
one aspect of an animal's environment while ignoring other things 
(Posner, 1994). Because animals (including humans) have limited 
cognitive resources, there is a limit to how much sensory information 
they can process at any time. The phenomenon called ``attentional 
capture'' occurs when a stimulus (usually a stimulus that an animal is 
not concentrating on or attending to) ``captures'' an animal's 
attention. This shift in attention can occur consciously or 
subconsciously (for example, when an animal hears sounds that it 
associates with the approach of a predator) and the shift in attention 
can be sudden (Dukas, 2002; van Rij, 2007). Once a stimulus has 
captured an animal's attention, the animal can respond by ignoring the 
stimulus, assuming a ``watch and wait'' posture, or treat the stimulus 
as a disturbance and respond accordingly, which includes scanning for 
the source of the stimulus or ``vigilance'' (Cowlishaw et al., 2004).
    Vigilance is an adaptive behavior that helps animals determine the 
presence or absence of predators, assess their distance from 
conspecifics, or to attend cues from prey (Bednekoff and Lima, 1998; 
Treves, 2000). Despite those benefits, however, vigilance has a cost of 
time; when animals focus their attention on specific environmental 
cues, they are not attending to other activities such as foraging or 
resting. These effects have generally not been demonstrated for marine 
mammals, but studies involving fish and terrestrial animals have shown 
that increased vigilance may substantially reduce feeding rates (Saino, 
1994; Beauchamp and Livoreil, 1997; Fritz et al., 2002; Purser and 
Radford, 2011). Animals will spend more time being vigilant, which may 
translate to less time foraging or resting, when disturbance stimuli 
approach them more directly, remain at closer distances, have a greater 
group size (e.g., multiple surface vessels), or when they co-occur with 
times that an animal perceives increased risk (e.g., when they are 
giving birth or accompanied by a calf).
    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). For example, 
Madsen (1994) reported that pink-footed geese (Anser brachyrhynchus) in 
undisturbed habitat gained body mass and had about a 46 percent 
reproductive success rate compared with geese in disturbed habitat 
(being consistently scared off the fields on which they were foraging) 
which did not gain mass and had a 17 percent reproductive success rate. 
Similar reductions in reproductive success have been reported for mule 
deer (Odocoileus hemionus) disturbed by all-terrain vehicles (Yarmoloy 
et al., 1988), caribou (Rangifer tarandus caribou) disturbed by seismic 
exploration blasts (Bradshaw et al., 1998), and caribou disturbed by 
low-elevation military jet fights (Luick et al., 1996, Harrington and 
Veitch, 1992). Similarly, a study of elk (Cervus elaphus) that were 
disturbed experimentally by pedestrians concluded that the ratio of 
young to mothers was inversely related to disturbance rate (Phillips 
and Alldredge, 2000).
    The primary mechanism by which increased vigilance and disturbance 
appear to affect the fitness of individual animals is by disrupting an 
animal's

[[Page 79103]]

time budget and, as a result, reducing the time they might spend 
foraging and resting (which increases an animal's activity rate and 
energy demand while decreasing their caloric intake/energy).
    In a study of northern resident killer whales off Vancouver Island, 
exposure to boat traffic was shown to reduce foraging opportunities and 
increase traveling time (Williams et al., 2006). A simple bioenergetics 
model was applied to show that the reduced foraging opportunities 
equated to a decreased energy intake of 18 percent, while the increased 
traveling incurred an increased energy output of 3-4 percent, which 
suggests that a management action based on avoiding interference with 
foraging might be particularly effective.
    On a related note, many animals perform vital functions, such as 
feeding, resting, traveling, and socializing, on a diel cycle (24-hr 
cycle). Behavioral reactions to noise exposure (such as disruption of 
critical life functions, displacement, or avoidance of important 
habitat) are more likely to be significant for fitness 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). It is important to note the difference between 
behavioral reactions lasting or recurring over multiple days and 
anthropogenic activities lasting or recurring over multiple days. For 
example, just because certain activities last for multiple days does 
not necessarily mean that individual animals will be either exposed to 
those activity-related stressors (i.e., sonar) for multiple days or 
further, exposed in a manner that would result in sustained multi-day 
substantive behavioral responses; however, special attention is 
warranted where longer-duration activities overlay areas in which 
animals are known to congregate for longer durations for biologically 
important behaviors.
    Stone (2015a) reported data from at-sea observations during 1,196 
airgun surveys from 1994 to 2010. When large arrays of airguns were 
firing, lateral displacement, more localized avoidance, or other 
changes in behavior were evident for most odontocetes. However, 
significant responses to large arrays were found only for the minke 
whale and fin whale. Behavioral responses observed included changes in 
swimming or surfacing behavior, with indications that cetaceans 
remained near the water surface at these times. Cetaceans were recorded 
as feeding less often when large arrays were active. Behavioral 
observations of gray whales during an air gun survey monitored whale 
movements and respirations pre-, during-, and post-seismic survey 
(Gailey et al., 2016). Behavioral state and water depth were the best 
`natural' predictors of whale movements and respiration and, after 
considering natural variation, none of the response variables were 
significantly associated with survey or vessel sounds.
    In order to understand how the effects of activities may or may not 
impact species and stocks of marine mammals, it is necessary to 
understand not only what the likely disturbances are going to be, but 
how those disturbances may affect the reproductive success and 
survivorship of individuals, and then how those impacts to individuals 
translate to population-level effects. Following on the earlier work of 
a committee of the U.S. National Research Council (NRC, 2005), New et 
al. (2014), in an effort termed the Potential Consequences of 
Disturbance (PCoD), outline an updated conceptual model of the 
relationships linking disturbance to changes in behavior and 
physiology, health, vital rates, and population dynamics. In this 
framework, behavioral and physiological changes can have direct (acute) 
effects on vital rates, such as when changes in habitat use or 
increased stress levels raise the probability of mother-calf separation 
or predation; they can have indirect and long-term (chronic) effects on 
vital rates, such as when changes in time/energy budgets or increased 
disease susceptibility affect health, which then affects vital rates; 
or they can have no effect to vital rates (New et al., 2014). In 
addition to outlining this general framework and compiling the relevant 
literature that supports it, the authors chose four example species for 
which extensive long-term monitoring data exist (southern elephant 
seals, North Atlantic right whales, Ziphiidae beaked whales, and 
bottlenose dolphins) and developed state-space energetic models that 
can be used to effectively forecast longer-term, population-level 
impacts from behavioral changes. While these are very specific models 
with very specific data requirements that cannot yet be applied broadly 
to project-specific risk assessments for the majority of species, they 
are a critical first step towards being able to quantify the likelihood 
of a population level effect.
    Since New et al. (2014), several publications have described models 
developed to examine the long-term effects of environmental or 
anthropogenic disturbance of foraging on various life stages of 
selected species (sperm whale, Farmer et al. (2018); California sea 
lion, McHuron et al. (2018); blue whale, Pirotta et al. (2018a)). These 
models continue to add to refinement of the approaches to the PCoD 
framework. Such models also help identify what data inputs require 
further investigation. Pirotta et al. (2018b) provides a review of the 
PCoD framework with details on each step of the process and approaches 
to applying real data or simulations to achieve each step.
    New et al. (2020) found that closed populations of dolphins could 
not withstand a higher probability of disturbance, compared to open 
populations with no limitation on food. Two bottlenose dolphin 
populations in Australia were also modeled over 5 years against a 
number of disturbances (Reed et al., 2020), and results indicated that 
habitat/noise disturbance had little overall impact on population 
abundances in either location, even in the most extreme impact 
scenarios modeled. By integrating different sources of data (e.g., 
controlled exposure data, activity monitoring, telemetry tracking, and 
prey sampling) into a theoretical model to predict effects from sonar 
on a blue whale's daily energy intake, Pirotta et al. (2021) found that 
tagged blue whales' activity budgets, lunging rates, and ranging 
patterns caused variability in their predicted cost of disturbance. 
Dunlop et al. (2021) modeled migrating humpback whale mother-calf pairs 
in response to seismic surveys using both a forwards and backwards 
approach. While a typical forwards approach can determine if a stressor 
would have population-level consequences, Dunlop et al. demonstrated 
that working backwards through a PCoD model can be used to assess the 
``worst case'' scenario for an interaction of a target species and 
stressor. This method may be useful for future management goals when 
appropriate data becomes available to fully support the model. Harbor 
porpoise movement and foraging were modeled for baseline periods and 
then for periods with seismic surveys as well; the models demonstrated 
that the seasonality of the seismic activity was an important predictor 
of impact (Gallagher et al., 2021).
    Nearly all PCoD studies 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; Wilson 
et al., 2020; Harwood and Booth

[[Page 79104]]

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). NMFS expects that any behavioral responses that would occur 
due to animals being exposed to construction activity would be 
temporary, with behavior returning to a baseline state shortly after 
the acoustic stimuli ceases. 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.

Potential Effects From Explosive Sources

    With respect to the noise from underwater explosives, the same 
acoustic-related impacts described above apply and are not repeated 
here. Noise from explosives can cause hearing impairment if an animal 
is close enough to the sources; however, because noise from an 
explosion is discrete, lasting less than approximately one second, no 
behavioral impacts below the TTS threshold are anticipated considering 
that Revolution Wind would not detonate more than one UXO/MEC per day 
(and no more than 13 only throughout the life of the proposed rule). 
This section focuses on the pressure-related impacts of underwater 
explosives, including physiological injury and mortality.
    Underwater explosive detonations send a shock wave and sound energy 
through the water and can release gaseous by-products, create an 
oscillating bubble, or cause a plume of water to shoot up from the 
water surface. The shock wave and accompanying noise are of most 
concern to marine animals. Depending on the intensity of the shock wave 
and size, location, and depth of the animal, an animal can be injured, 
killed, suffer non-lethal physical effects, experience hearing-related 
effects with or without behavioral responses, or exhibit temporary 
behavioral responses or tolerance from hearing the blast sound. 
Generally, exposures to higher levels of impulse and pressure levels 
would result in greater impacts to an individual animal.
    Injuries resulting from a shock wave take place at boundaries 
between tissues of different densities. Different velocities are 
imparted to tissues of different densities, and this can lead to their 
physical disruption. Blast effects are greatest at the gas-liquid 
interface (Landsberg, 2000). Gas-containing organs, particularly the 
lungs and gastrointestinal tract, are especially susceptible (Goertner, 
1982; Hill, 1978; Yelverton et al., 1973). Intestinal walls can bruise 
or rupture, with subsequent hemorrhage and escape of gut contents into 
the body cavity. Less severe gastrointestinal tract injuries include 
contusions, petechiae (small red or purple spots caused by bleeding in 
the skin), and slight hemorrhaging (Yelverton et al., 1973).
    Because the ears are the most sensitive to pressure, they are the 
organs most sensitive to injury (Ketten, 2000). Sound-related damage 
associated with sound energy from detonations can be theoretically 
distinct from injury from the shock wave, particularly farther from the 
explosion. If a noise is audible to an animal, it has the potential to 
damage the animal's hearing by causing decreased sensitivity (Ketten, 
1995). Lethal impacts are those that result in immediate death or 
serious debilitation in or near an intense source and are not, 
technically, pure acoustic trauma (Ketten, 1995). Sublethal impacts 
include hearing loss, which is caused by exposures to perceptible 
sounds. Severe damage (from the shock wave) to the ears includes 
tympanic membrane rupture, fracture of the ossicles, and damage to the 
cochlea, hemorrhage, and cerebrospinal fluid leakage into the middle 
ear. Moderate injury implies partial hearing loss due to tympanic 
membrane rupture and blood in the middle ear. Permanent hearing loss 
also can occur when the hair cells are damaged by one very loud event, 
as well as by prolonged exposure to a loud noise or chronic exposure to 
noise. The level of impact from blasts depends on both an animal's 
location and, at outer zones, on its sensitivity to the residual noise 
(Ketten, 1995).
    Given the mitigation measures proposed, it is unlikely that any of 
the more serious injuries or mortality discussed above would result 
from any UXO/MEC detonation that Revolution Wind might need to 
undertake. PTS, TTS, and brief startle reactions are the most likely 
impacts to result from this activity.

Potential Effects of Vessel Strike

    Vessel collisions with marine mammals, also referred to as vessel 
strikes or ship strikes, can result in death or serious injury of the 
animal. Wounds resulting from ship strike may include massive trauma, 
hemorrhaging, broken bones, or propeller lacerations (Knowlton and 
Kraus, 2001). An animal at the surface could be struck directly by a 
vessel, a surfacing animal could hit the bottom of a vessel, or an 
animal just below the surface could be cut by a vessel's propeller. 
Superficial strikes may not kill or result in the death of the animal. 
Lethal interactions are typically associated with large whales, which 
are occasionally found draped across the bulbous bow of large 
commercial ships upon arrival in port. Although smaller cetaceans are 
more maneuverable in relation to large vessels than are large whales, 
they may also be susceptible to strike. The severity of injuries 
typically depends on the size and speed of the vessel (Knowlton and 
Kraus, 2001; Laist et al., 2001; Vanderlaan and Taggart, 2007; Conn and 
Silber, 2013). Impact forces increase with speed, as does the 
probability of a strike at a given distance (Silber et al., 2010; Gende 
et al., 2011).
    The most vulnerable marine mammals are those that spend extended 
periods of time at the surface in order to restore oxygen levels within 
their tissues after deep dives (e.g., the sperm whale). In addition, 
some baleen whales seem generally unresponsive to vessel sound, making 
them more susceptible to vessel collisions (Nowacek et al., 2004). 
These species are primarily large, slow moving whales. Marine mammal 
responses to vessels may include avoidance and changes in dive pattern 
(NRC, 2003).
    An examination of all known ship strikes from all shipping sources 
(civilian and military) indicates vessel speed is a principal factor in 
whether a vessel strike occurs and, if so, whether it results in 
injury, serious injury, or mortality (Knowlton and Kraus, 2001; Laist 
et al., 2001; Jensen and Silber, 2003; Pace and Silber, 2005; 
Vanderlaan and Taggart, 2007; Conn and Silber, 2013). In assessing 
records in which vessel speed was known, Laist et al. (2001) found a 
direct relationship between the occurrence of a whale strike and the 
speed of the vessel involved in the collision. The authors concluded 
that most deaths occurred when a vessel was traveling in excess of 13 
knots.
    Jensen and Silber (2003) detailed 292 records of known or probable 
ship strikes of all large whale species from 1975 to 2002. Of these, 
vessel speed at the time of collision was reported for 58 cases. Of 
these 58 cases, 39 (or 67 percent) resulted in serious injury or death 
(19 of those resulted in serious injury as determined by blood in the 
water, propeller gashes or severed tailstock, and fractured skull, jaw, 
vertebrae, hemorrhaging, massive bruising or other injuries noted 
during necropsy and 20 resulted in death). Operating speeds of vessels 
that struck various species of large whales ranged from 2 to 51 knots. 
The majority (79 percent) of these strikes occurred at

[[Page 79105]]

speeds of 13 knots or greater. The average speed that resulted in 
serious injury or death was 18.6 knots. Pace and Silber (2005) found 
that the probability of death or serious injury increased rapidly with 
increasing vessel speed. Specifically, the predicted probability of 
serious injury or death increased from 45 to 75 percent as vessel speed 
increased from 10 to 14 knots, and exceeded 90 percent at 17 knots. 
Higher speeds during collisions result in greater force of impact and 
also appear to increase the chance of severe injuries or death. While 
modeling studies have suggested that hydrodynamic forces pulling whales 
toward the vessel hull increase with increasing speed (Clyne 1999; 
Knowlton et al., 1995), this is inconsistent with Silber et al. (2010), 
which demonstrated that there is no such relationship (i.e., 
hydrodynamic forces are independent of speed).
    In a separate study, Vanderlaan and Taggart (2007) analyzed the 
probability of lethal mortality of large whales at a given speed, 
showing that the greatest rate of change in the probability of a lethal 
injury to a large whale as a function of vessel speed occurs between 
8.6 and 15 knots. The chances of a lethal injury decline from 
approximately 80 percent at 15 knots to approximately 20 percent at 8.6 
knots. At speeds below 11.8 knots, the chances of lethal injury drop 
below 50 percent, while the probability asymptotically increases toward 
100 percent above 15 knots.
    The Jensen and Silber (2003) report notes that the Large Whale Ship 
Strike Database represents a minimum number of collisions, because the 
vast majority probably goes undetected or unreported. In contrast, 
Revolution Wind's personnel are likely to detect any strike that does 
occur because of the required personnel training and lookouts, along 
with the inclusion of PSOs (as described in the Proposed Mitigation 
section), and they are required to report all ship strikes involving 
marine mammals.
    NMFS is not aware of any documented vessel strikes of marine 
mammals by Revolution Wind or [Oslash]rsted during previous site 
characterization surveys. Given the extensive mitigation and monitoring 
measures (see the Proposed Mitigation and Proposed Monitoring and 
Reporting section) that would be required of Revolution Wind, NMFS 
believes that vessel strike of any marine mammal is not likely to 
occur, nor are we proposing to authorize take from vessel strikes.

Marine Mammal Habitat

    Revolution Wind's proposed construction activities could 
potentially affect marine mammal habitat through the introduction of 
impacts to the prey species of marine mammals, acoustic habitat (sound 
in the water column), and water quality.
    The presence of structures such as wind turbines is likely to 
result in both local and broader oceanographic effects. However, the 
scale of impacts is difficult to predict and may vary from hundreds of 
meters for local individual turbine impacts (Schultze et al., 2020) to 
large-scale dipoles of surface elevation changes stretching hundreds of 
kilometers (Christiansen et al., 2022).
Effects on Prey
    Sound may affect marine mammals through impacts on the abundance, 
behavior, or distribution of prey species (e.g., crustaceans, 
cephalopods, fish, and 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). 
The most likely effects on fishes exposed to loud, intermittent, low-
frequency sounds are behavioral responses (i.e., flight or avoidance). 
Short duration, sharp sounds (such as pile driving or air guns) can 
cause overt or subtle changes in fish behavior and local distribution. 
The reaction of fish to acoustic sources depends on the physiological 
state of the fish, past exposures, motivation (e.g., feeding, spawning, 
migration), and other environmental factors. Key impacts to fishes may 
include behavioral responses, hearing damage, barotrauma (pressure-
related injuries), and mortality. While it is clear that the behavioral 
responses of individual prey, such as displacement or other changes in 
distribution, can have direct impacts on the foraging success of marine 
mammals, the effects on marine mammals of individual prey that 
experience hearing damage, barotrauma, or mortality is less clear, 
though obviously population scale impacts that meaningfully reduce the 
amount of prey available could have more serious impacts.
    In terms of physiology, multiple scientific studies have documented 
a lack of mortality or physiological effects to fish from exposure to 
low- and mid-frequency sonar and other sounds (Halvorsen et al., 2012; 
J[oslash]rgensen et al., 2005; Juanes et al., 2017; Kane et al., 2010; 
Kvadsheim and Sevaldsen, 2005; Popper et al., 2007; Popper et al., 
2016; Watwood et al., 2016). Techer et al. (2017) exposed carp in 
floating cages for up to 30 days to low-power 23 and 46 kHz source 
without any significant physiological response. Other studies have 
documented either a lack of TTS in species whose hearing range cannot 
perceive sonar, or for those species that could perceive sonar-like 
signals, any TTS experienced would be recoverable (Halvorsen et al., 
2012; Ladich and Fay, 2013; Popper and Hastings, 2009a, 2009b; Popper 
et al., 2014; Smith, 2016). Only fishes that have specializations that 
enable them to hear sounds above about 2,500 Hz (2.5 kHz) such as 
herring (Halvorsen et al., 2012; Mann et al., 2005; Mann, 2016; Popper 
et al., 2014) would have the potential to receive TTS or exhibit 
behavioral responses from Revolution Wind's activities.
    In terms of behavioral responses, Watwood et al. (2016) documented 
no behavioral responses by reef fish after exposure to mid-frequency 
active sonar. Doksaeter et al. (2009, 2012) reported no behavioral 
responses to mid-frequency sonar (such as naval sonar) by Atlantic 
herring; specifically, no escape reactions (vertically or horizontally) 
were observed in free swimming herring exposed to mid-frequency sonar 
transmissions. Based on these results (Doksaeter et al., 2009; 
Doksaeter et al., 2012; Sivle et al., 2012), Sivle et al. (2014) 
created a model in order to report on the possible population-level 
effects on Atlantic herring from active sonar. The authors concluded 
that the use of sonar poses little risk to populations of herring 
regardless of season, even when the herring populations are aggregated 
and directly exposed to sonar. Finally, Bruintjes et al. (2016) 
commented that fish exposed to any short-term noise within their 
hearing range might initially startle, but would quickly return to 
normal behavior.
    Occasional behavioral reactions to activities that produce 
underwater noise sources are unlikely to cause long-term consequences 
for individual fish or populations. The most likely impact to fish from 
impact and vibratory pile driving activities in the RWF would be 
temporary behavioral avoidance of the area. 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. 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

[[Page 79106]]

of individual pile driving events and the relatively small area being 
affected.
    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, Revolution Wind would utilize a 
sound attenuation device which would reduce potential for injury to 
marine mammal prey. Other fish that experience hearing loss as a result 
of exposure to explosions and impulsive sound sources may have a 
reduced ability to detect relevant sounds such as predators, prey, or 
social vocalizations. However, PTS has not been known to occur in 
fishes and any hearing loss in fish may be as temporary as the 
timeframe required to repair or replace the sensory cells that were 
damaged or destroyed (Popper et al., 2005; Popper et al., 2014; Smith 
et al., 2006).
    It is also possible for fish to be injured or killed by an 
explosion from UXO/MEC detonation. The shock wave from an underwater 
explosion is lethal to fish at close range, causing massive organ and 
tissue damage and internal bleeding (Keevin and Hempen, 1997). At 
greater distance from the detonation point, the extent of mortality or 
injury depends on a number of factors including fish size, body shape, 
orientation, and species (Keevin and Hempen, 1997; Wright, 1982). 
Species with gas-filled organs are more susceptible to injury and 
mortality than those without them (Gaspin, 1975; Gaspin et al., 1976; 
Goertner et al., 1994). Barotrauma injuries have been documented during 
controlled exposure to impact pile driving (Halvorsen et al., 2012b; 
Casper et al., 2013).
    Fish not killed or driven from a location by an explosion might 
change their behavior, feeding pattern, or distribution. Changes in 
behavior of fish have been observed as a result of sound produced by 
explosives, with effect intensified in areas of hard substrate (Wright, 
1982). Stunning from pressure waves could also temporarily immobilize 
fish, making them more susceptible to predation. The abundances of 
various fish (and invertebrates) near the detonation point for 
explosives could be altered for a few hours before animals from 
surrounding areas repopulate the area. However, these populations would 
likely be replenished as waters near the detonation point are mixed 
with adjacent waters. Repeated exposure of individual fish to sounds 
from underwater explosions is not likely and are expected to be short-
term and localized. Long-term consequences for fish populations would 
not be expected.
    UXO/MEC detonations would be dispersed in space and time; 
therefore, repeated exposure of individual fishes are unlikely. 
Mortality and injury effects to fishes from explosives would be 
localized around the area of a given in-water explosion, but only if 
individual fish and the explosive (and immediate pressure field) were 
co-located at the same time. Repeated exposure of individual fish to 
sound and energy from underwater explosions is not likely given fish 
movement patterns, especially schooling prey species. Most acoustic 
effects, if any, are expected to be short-term and localized. Long-term 
consequences for fish populations including key prey species within the 
project area would not be expected.
    Required soft-starts would allow prey and marine mammals to move 
away from the pile-driving source prior to any noise levels that may 
physically injure prey and the use of the noise attenuation devices 
would reduce noise levels to the degree any mortality or injury of prey 
is also minimized. Use of bubble curtains, in addition to reducing 
impacts to marine mammals, for example, is a key mitigation measure in 
reducing injury and mortality of ESA-listed salmon on the West Coast. 
However, we recognize some mortality, physical injury and hearing 
impairment in marine mammal prey may occur, but we anticipate the 
amount of prey impacted in this manner is minimal compared to overall 
availability. Any behavioral responses to pile driving by marine mammal 
prey are expected to be brief. We expect that other impacts such as 
stress or masking would occur in fish that serve as marine mammals prey 
(Popper et al., 2019); however, those impacts would be limited to the 
duration of impact pile driving and during any UXO/MEC detonations.
    In addition to fish, prey sources such as marine invertebrates 
could potentially be impacted by noise stressors as a result of the 
proposed activities. Invertebrates appear to be able to detect sounds 
(Pumphrey, 1950; Frings and Frings, 1967) and are most sensitive to 
low-frequency sounds (Packard et al., 1990; Budelmann and Williamson, 
1994; Lovell et al., 2005; Mooney et al., 2010). Data on response of 
invertebrates such as squid, another marine mammal prey species, to 
anthropogenic sound is more limited (de Soto, 2016; Sole et al., 
2017b). Data suggest that cephalopods are capable of sensing the 
particle motion of sounds and detect low frequencies up to 1-1.5 kHz, 
depending on the species, and so are likely to detect air gun noise 
(Kaifu et al., 2008; Hu et al., 2009; Mooney et al., 2010; Samson et 
al., 2014). Jones et al. (2020) found that when squid (Doryteuthis 
pealeii) were exposed to impulse pile-driving noise, body pattern 
changes, inking, jetting, and startle responses were observed and 
nearly all squid exhibited at least one response. However, these 
responses occurred primarily during the first eight impulses and 
diminished quickly, indicating potential rapid, short-term habituation. 
Auditory injuries (lesions occurring on the statocyst sensory hair 
cells) have been reported upon controlled exposure to low-frequency 
sounds, suggesting that cephalopods are particularly sensitive to low-
frequency sound (Andre et al., 2011; Sole et al., 2013). Cumulatively 
for squid as a prey species, individual and population impacts from 
exposure to explosives, like fish, are not likely to be significant, 
and explosive impacts would be short-term and localized.
    There is little information concerning potential impacts of noise 
on zooplankton populations. However, one recent study (McCauley et al., 
2017) investigated zooplankton abundance, diversity, and mortality 
before and after exposure to air gun noise, finding that the exposure 
resulted in significant depletion for more than half the taxa present 
and that there were two to three times more dead zooplankton after air 
gun exposure compared with controls for all taxa. The majority of taxa 
present were copepods and cladocerans; for these taxa, the range within 
which effects on abundance were detected was up to approximately 1.2 
km. In order to have significant impacts on r-selected species such as 
plankton, the spatial or temporal scale of impact must be large in 
comparison with the ecosystem concerned (McCauley et al., 2017). 
Therefore, the large scale of effect observed here is of concern--
particularly where repeated noise exposure is expected--and further 
study is warranted.
    The presence of large numbers of turbines has been shown to impact 
meso- and sub-meso-scale water column

[[Page 79107]]

circulation, which can affect the density, distribution, and energy 
content of zooplankton, and thereby their availability as marine mammal 
prey. The presence and operation of structures such as wind turbines 
are, in general, likely to result in local and broader oceanographic 
effects in the marine environment, and may disrupt marine mammal prey 
such as dense aggregations and distribution of zooplankton through 
altering the strength of tidal currents and associated fronts, changes 
in stratification, primary production, the degree of mixing, and 
stratification in the water column (Chen et al., 2021, Johnson et al., 
2021, Christiansen et al., 2022, Dorrell et al., 2022). However, the 
scale of impacts is difficult to predict and may vary from meters to 
hundreds of meters for local individual turbine impacts (Schultze et 
al., 2020) to large-scale dipoles of surface elevation changes 
stretching hundreds of kilometers (Christiansen et al., 2022).
    Revolution Wind intends to install up to 79 turbines in 2024, which 
would become operational that same year. As described above, there is 
scientific uncertainty around the scale of oceanographic impacts 
(meters to kilometers) associated with turbine operation. Revolution 
Wind is located in a biologically productive area on an inshore 
temperate shelf sea on the inner portion of the southern New England 
continental shelf, an area of where the oceanography is dominated by 
complex interactions among wind-driven and tidal processes, and 
seasonal variations in solar heating. Shelf waters undergo a pronounced 
seasonal temperature cycle, influenced largely by air-sea interaction. 
Seasonality in salinity, associated mainly with spring freshening due 
to episodic coastal runoff, is less regular than that of temperature, 
and commonly weaker than inter-annual variability. Stratification, the 
vertical gradient in density associated with horizontal layering of 
water such that less dense layers overlie denser layers, results from 
comparably important influences of river freshening and surface 
heating. In Rhode Island Sound and the offshore project area during 
late fall and winter, stratification is minimal and circulation is a 
weak upwelling pattern directed offshore at shallow depths, and onshore 
near the seafloor. In spring and summer, strong stratification develops 
due to solar heating and a system of more distinct currents develops. 
Over most of the region, tidal currents are generally stronger than or 
comparable to seasonal mean flow patterns, as are weather-band current 
variations driven by the wind (Codiga and Ullman, 2010). Regional 
surface winds in winter average about 4-12 m/s (9-27 mi/hr) east-
southeastward and, due to storms, are highly variable with peak speeds 
up to about 25 m/s (56 mi/hr). Summer winds are much less variable and 
weaker, averaging 2.5-7.5 m/s (6-17 mi/hr), oriented east-northeastward 
(Codiga and Ullman 2010). Fall and winter winds promote increased water 
column mixing, bringing nutrients into the water column for uptake by 
phytoplankton in Rhode Island Sound and the offshore project area 
during late fall and winter, stratification is minimal and circulation 
is a weak upwelling pattern directed offshore at shallow depths, and 
onshore near the seafloor. In spring and summer, strong stratification 
develops due to solar heating and a system of more distinct currents 
develops. Over most of the region, tidal currents are generally 
stronger than or comparable to seasonal mean flow patterns, as are 
weather-band current variations driven by the wind (Codiga and Ullman, 
2010). Regional surface winds in winter average about 4-12 m/s (9-27 
mi/hr) east-southeastward and, due to storms, are highly variable with 
peak speeds up to about 25 m/s (56 mi/hr). Summer winds are much less 
variable and weaker, averaging 2.5-7.5 m/s (6-17 mi/hr), oriented east-
northeastward (Codiga and Ullman, 2010). Fall and winter winds promote 
increased water column mixing, bringing nutrients into the water column 
for uptake by phytoplankton. Seasonal stratification leads to 
pronounced spring and early fall blooms of phytoplankton and 
subsequently increased biological productivity of upper trophic level 
species (Codiga and Ullman, 2010).
    In general, the scale of impacts to oceanographic features from 
offshore wind development is difficult to predict and may vary from 
hundreds of meters for local individual turbine impacts (Schultze et 
al., 2020) to large-scale dipoles of surface elevation changes 
stretching hundreds of kilometers when considering multiple wind farms 
(Christiansen et al., 2022). We anticipate any impacts to plankton 
aggregation, and hence availability as marine mammal prey, from turbine 
presence and operation as a result of oceanographic changes from the 
RWF (i.e., 79 turbines) would be limited (e.g., Schultze et al., 2020). 
Overall, the combined impacts of sound exposure, explosions, and 
oceanographic impacts on marine mammal habitat resulting from the 
proposed activities would not be expected to have measurable effects on 
populations of marine mammal prey species. Prey species exposed to 
sound might move away from the sound source, experience TTS, experience 
masking of biologically relevant sounds, or show no obvious direct 
effects.
Acoustic Habitat
    Acoustic habitat is the soundscape, which encompasses all of the 
sound present in a particular location and time, as a whole when 
considered from the perspective of the animals experiencing it. Animals 
produce sound for, or listen for sounds produced by, conspecifics 
(communication during feeding, mating, and other social activities), 
other animals (finding prey or avoiding predators), and the physical 
environment (finding suitable habitats, navigating). Together, sounds 
made by animals and the geophysical environment (e.g., produced by 
earthquakes, lightning, wind, rain, waves) make up the natural 
contributions to the total acoustics of a place. These acoustic 
conditions, termed acoustic habitat, are one attribute of an animal's 
total habitat.
    Soundscapes are also defined by, and acoustic habitat influenced 
by, the total contribution of anthropogenic sound. This may include 
incidental emissions from sources such as vessel traffic or may be 
intentionally introduced to the marine environment for data acquisition 
purposes (as in the use of air gun arrays) or for Navy training and 
testing purposes (as in the use of sonar and explosives and other 
acoustic sources). Anthropogenic noise varies widely in its frequency, 
content, duration, and loudness and these characteristics greatly 
influence the potential habitat-mediated effects to marine mammals 
(please also see the previous discussion on Masking), which may range 
from local effects for brief periods of time to chronic effects over 
large areas and for long durations. Depending on the extent of effects 
to habitat, animals may alter their communications signals (thereby 
potentially expending additional energy) or miss acoustic cues (either 
conspecific or adventitious). Problems arising from a failure to detect 
cues are more likely to occur when noise stimuli are chronic and 
overlap with biologically relevant cues used for communication, 
orientation, and predator/prey detection (Francis and Barber, 2013). 
For more detail on these concepts see, e.g., Barber et al., 2009; 
Pijanowski et al., 2011; Francis and Barber, 2013; Lillis et al., 2014.
    The term ``listening area'' refers to the region of ocean over 
which sources of sound can be detected by an animal at the center of 
the space. Loss of

[[Page 79108]]

communication space concerns the area over which a specific animal 
signal, used to communicate with conspecifics in biologically important 
contexts (e.g., foraging, mating), can be heard, in noisier relative to 
quieter conditions (Clark et al., 2009). Lost listening area concerns 
the more generalized contraction of the range over which animals would 
be able to detect a variety of signals of biological importance, 
including eavesdropping on predators and prey (Barber et al., 2009). 
Such metrics do not, in and of themselves, document fitness 
consequences for the marine animals that live in chronically noisy 
environments. Long-term population-level consequences mediated through 
changes in the ultimate survival and reproductive success of 
individuals are difficult to study, and particularly so underwater. 
However, it is increasingly well documented that aquatic species rely 
on qualities of natural acoustic habitats, with researchers quantifying 
reduced detection of important ecological cues (e.g., Francis and 
Barber, 2013; Slabbekoorn et al., 2010) as well as survivorship 
consequences in several species (e.g., Simpson et al., 2014; Nedelec et 
al., 2015).
    Sound produced from construction activities in the Revolution Wind 
project area may be widely dispersed or concentrated in small areas for 
varying periods. Any anthropogenic noise attributed to construction 
activities in the project area would be temporary, and the affected 
area would be expected to immediately return to the original state when 
these activities cease.
Water Quality
    Indirect effects of explosives and unexploded ordnance to marine 
mammals via sediment are possible in the immediate vicinity of the 
ordnance. Degradation products of Royal Demolition Explosive are not 
toxic to marine organisms at realistic exposure levels (Rosen and 
Lotufo, 2010). Relatively low solubility of most explosives and their 
degradation products means that concentrations of these contaminants in 
the marine environment are relatively low and readily diluted. 
Furthermore, while explosives and their degradation products were 
detectable in marine sediment approximately 6-12 in (0.15-0.3 m) away 
from degrading ordnance, the concentrations of these compounds were not 
statistically distinguishable from background beyond 3-6 ft (1-2 m) 
from the degrading ordnance (Rosen and Lotufo, 2010). Taken together, 
it is possible that marine mammals could be exposed to degrading 
explosives, but it would be within a very small radius of the explosive 
(1-6 ft (0.3-2 m)).
    Equipment types used by Revolution Wind within the project area, 
including ships and other marine vessels, potentially aircrafts, and 
other equipment, are also potential sources of by-products. All 
equipment would be properly maintained in accordance with applicable 
legal requirements. All such operating equipment would meet Federal 
water quality standards, where applicable.
Offshore Wind Farm Operational Noise
    Although this proposed rulemaking primarily covers the noise 
produced from construction activities relevant to the Revolution Wind 
offshore wind facility, operational noise was a consideration in NMFS' 
analysis of the project, as all 79 turbines would become operational 
within the effective dates of the rule, beginning no sooner than Q2 
2024. It is expected that all turbines would be operational by Q4 2024. 
Once operational, offshore wind turbines are known to produce 
continuous, non-impulsive underwater noise, primarily below 8 kHz.
    In both newer, quieter, direct-drive systems (such as what has been 
proposed for Revolution Wind) and older generation, geared turbine 
designs, recent scientific studies indicate that operational noise from 
turbines is on the order of 110 to 125 dB re 1 [mu]Pa root-mean-square 
sound pressure level (SPLrms) at an approximate distance of 
50 m (Tougaard et al., 2020). Tougaard et al. (2020) further noted that 
sound levels could reach as high as 128 dB re 1 [mu]Pa 
SPLrms in the 10 Hz to 8 kHz range. However, the Tougaard et 
al. (2020) study assumed that the largest monopile-specific WTG was 3.6 
MW, which is much smaller than those being considered for the 
Revolution Wind project. Tougaard further stated that the operational 
noise produced by WTGs is static in nature and lower than noise 
produced by passing ships. This is a noise source in this region to 
which marine mammals are likely already habituated. Furthermore, 
operational noise levels are likely lower than those ambient levels 
already present in active shipping lanes, such that operational noise 
would likely only be detected in very close proximity to the WTG 
(Thomsen et al., 2006; Tougaard et al., 2020). In addition, Madsen et 
al. (2006) found the intensity of noise generated by operational wind 
turbines to be much less than the noise produced during construction, 
although this observation was based on a single turbine with a maximum 
power of 2 MW. Other studies by Jansen and de Jong (2016) and Tougaard 
et al. (2009) determined that, while marine mammals would be able to 
detect operational noise from offshore wind farms (again, based on 
older 2 MW models) for several thousand kilometers, they expected no 
significant impacts on individual survival, population viability, 
marine mammal distribution, or the behavior of the animals considered 
in their study (i.e., harbor porpoises and harbor seals).
    More recently, St[ouml]ber and Thomsen (2021) used monitoring data 
and modeling to estimate noise generated by more recently developed, 
larger (10 MW) direct-drive WTGs. Their findings, similar to Tougaard 
et al. (2020), demonstrated that modern turbine designs could generate 
higher operational noise levels (170 to 177 dB re 1 [mu]Pa 
SPLrms for a 10 MW WTG) than those previously reported for 
older models. However, the results in the study by St[ouml]ber and 
Thomsen (2021), have not been validated and were based on a small 
sample size. NMFS is requiring Revolution Wind to monitor noise 
generated by turbine operation to better understand noise levels from 
the advanced design turbines used in the Revolution Wind project (see 
Proposed Monitoring and Reporting section).
    Operational noise was assessed in the DEIS BOEM developed for the 
Revolution Wind Project, within which BOEM states that operational 
noise would primarily consist of low-frequency sounds (60 to 300 Hz) 
and relatively low SPLs. While it is possible that some lower-frequency 
sounds produced by marine mammal species (e.g., North Atlantic right 
whale upcalls (Parks et al., 2009)) may fall within similar frequency 
ranges as operational wind turbine noise, this assessment was based on 
the older generation of turbines rather than more recent drive shafts. 
NMFS acknowledges that more research on WTG operational noise should be 
conducted to fill the current data gaps, including source level 
characterization and any potential influences on marine mammals and 
their prey. Revolution Wind did not request take and, based on the 
relatively small number of turbines and limited duration turbines would 
be operating within the proposed rule timeframe, NMFS is preliminarily 
not proposing to authorize take of marine mammals incidental to 
operational noise from WTGs. Therefore, the topic is not discussed or 
analyzed further herein.
Reef Effects
    The presence of the RWF monopile foundations, scour protection, and 
cable protection would result in a conversion

[[Page 79109]]

of the existing sandy bottom habitat to a hard bottom habitat with 
areas of vertical structural relief (Revolution Wind, 2022). This could 
potentially alter the existing habitat by creating an ``artificial reef 
effect'' that results in colonization by assemblages of both sessile 
and mobile animals within the new hard-bottom habitat (Wilhelmsson et 
al., 2006; Reubens et al., 2013; Bergstr[ouml]m et al., 2014; Coates et 
al., 2014).
    Artificial structures can create increased habitat heterogeneity 
important for species diversity and density (Langhamer, 2012). The WTG 
and OSS foundations would extend through the water column, which may 
serve to increase settlement of meroplankton or planktonic larvae on 
the structures in both the pelagic and benthic zones (Boehlert and 
Gill, 2010). Fish and invertebrate species are also likely to aggregate 
around the foundations and scour protection which could provide 
increased prey availability and structural habitat (Boehlert and Gill, 
2010; Bonar et al., 2015).
    The WTG foundations would have an estimated footprint of 
approximately 70 acres and the OSS foundations would have an estimated 
footprint of up to 1.4 acres (COP Table 3.3.4-2) (Revolution-Wind, 
2022), providing up to 72 acres of heterogeneous habitat throughout the 
20-35-year operational life of this Project. Numerous studies have 
documented significantly higher fish concentrations, including species 
like cod and pouting (Trisopterus luscus), flounder (Platichthys 
flesus), eelpout (Zoarces viviparus), and eel (Anguila anguilla), near 
the foundations than in surrounding soft bottom habitat (Langhamer and 
Wilhelmsson, 2009; Bergstr[ouml]m et al., 2013; Reubens et al., 2013). 
In the German Bight portion of the North Sea, fish were most densely 
congregated near the anchorages of jacket foundations, and the 
structures extending through the water column were thought to make it 
more likely that juvenile or larval fish encounter and settle on them 
(Rhode Island Coastal Resources Management Council (RI-CRMC), 2010; 
Krone et al., 2013). In addition, fish can take advantage of the 
shelter provided by these structures while also being exposed to 
stronger currents created by the structures, which generate increased 
feeding opportunities and decreased potential for predation 
(Wilhelmsson et al., 2006). The presence of the foundations and 
resulting fish aggregations around the foundations is expected to be a 
long-term habitat impact, but the increase in prey availability could 
potentially be beneficial for some marine mammals.
    The most likely impact to marine mammal habitat from the project is 
expected to be from impact and vibratory pile driving and UXO/MEC 
detonations, which may affect marine mammal food sources such as forage 
fish and could also affect acoustic habitat (see the Auditory Masking 
section) effects on marine mammal prey (e.g., fish).
    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 relatively 
minor and temporary due to the expected short daily duration of 
individual pile driving events and the relatively small areas being 
affected. The most likely impacts of prey fish from UXO/MEC 
detonations, if determined to be necessary, are injury or mortality if 
they are located within the vicinity when detonation occurs. However, 
given the likely spread of any UXOs/MECs in the project area, the low 
chance of detonation (as lift-and-shift and deflagration are the 
primary removal approaches), and that this area is not a biologically 
important foraging ground, overall effects should be minimal to marine 
mammal species. NMFS does not expect HRG acoustic sources to impact 
fish as most sources operate at frequencies likely outside the hearing 
range of the primary prey species in the project area. As described 
previously, the placement and operation of wind turbines can also 
impact hydrographic patterns, though these impacts assessed through 
this rule are expected to be minimal given the relatively small number 
of turbines that would be operational and the short amount of time 
covered under the rule.
    These potential impacts on prey could influence the distribution of 
marine mammals within the project area, potentially necessitating 
additional energy expenditure to find and capture prey but, given the 
temporal and spatial scales anticipated for this project, not to the 
extent that would impact the reproduction or survival of any individual 
marine mammal. 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.
    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.
    Revolution Wind would be located within the migratory corridor BIA 
for North Atlantic right whales; however, the 68,450 acre (277 km\2\) 
lease area occupies a fraction of the available habitat for North 
Atlantic right whales migrating through the region (66,591,935 acres; 
269,488 km\2\). In addition, although the project area overlaps with a 
fin whale feeding BIA (March through October), a significantly larger 
year-round fin whale feeding BIA is located in the southern Gulf of 
Maine, to the east and north of the project area.
    Based on the information discussed herein, NMFS concludes that 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 the regulations, which will inform 
both NMFS' consideration of ``small numbers'' and the negligible impact 
determination.
    Authorized takes would primarily be by Level B harassment, as noise 
from impact and vibratory pile driving, HRG surveys, and UXO/MEC 
detonation(s) could result in behavioral disturbance or TTS. Impacts 
such as masking and TTS can contribute to behavior disturbances. There 
is also some potential for auditory injury (Level A harassment) of 
humpback whales, harbor porpoises, and gray and harbor seals (related 
to each species' hearing sensitivity) to result from impact pile 
driving and UXO/MEC detonations. For this action, this potential is 
limited to mysticetes, high-frequency cetaceans, and phocids due to 
their hearing sensitivities and the nature of the activities. As 
described below, the larger distances to the PTS thresholds, when 
considering marine mammal weighting functions, demonstrate this 
potential. For mid-frequency hearing sensitivities, when thresholds and 
weighting and the associated PTS zone sizes are considered, the 
potential for PTS from the noise produced by the project is

[[Page 79110]]

negligible. The proposed mitigation and monitoring measures are 
expected to minimize the amount and severity of such taking to the 
extent practicable (see Proposed Mitigation).
    As described previously, no serious injury or mortality is 
anticipated or proposed to be authorized for this activity. While, in 
general, mortality and serious injury of marine mammals could occur 
from UXO/MEC detonation if an animal is close enough to the source, the 
mitigation and monitoring measures included in the proposed rule would 
avoid this manner of take.
    Below we describe how the proposed take numbers are estimated.
    For acoustic impacts, generally speaking, we estimate take by 
considering: (1) acoustic thresholds above which NMFS believes the best 
available science indicates marine mammals will be behaviorally 
harassed or incur some degree of permanent hearing impairment; (2) the 
area or volume of water that will be ensonified above these levels in a 
day; (3) the density or occurrence of marine mammals within these 
ensonified areas; and, (4) and the number of days of activities.
    In this case, as described below, there are multiple lines of data 
with which to address density or occurrence and, for each species and 
activity, the largest value resulting from the three take estimation 
methods described below (i.e., density-based, PSO data-based, or mean 
group size) was carried forward as the amount of requested take, by 
Level B harassment. The amount of requested take, by Level A 
harassment, is based solely on density-based exposure estimates.
    Below, we describe the acoustic thresholds NMFS uses, discuss the 
marine mammal density and occurrence information used, and then 
describe the modeling and methodologies applied to estimate take for 
each of Revolution Wind's proposed construction activities. NMFS has 
carefully considered all information and analysis presented by the 
applicant as well as all other applicable information and, based on the 
best available science, concurs that the applicant's estimates of the 
types and amounts of take for each species and stock are complete and 
accurate.

Marine Mammal 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). Thresholds have also been developed to identify the 
pressure levels above which animals may incur different types of tissue 
damage (non-auditory injury or mortality) from exposure to pressure 
waves from explosive detonation. A summary of all NMFS' thresholds can 
be found at https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
    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 or exposure context (e.g., frequency, predictability, duty 
cycle, duration of the exposure, signal-to-noise ratio, distance to the 
source, ambient noise, and the receiving animals (hearing, motivation, 
experience, demography, behavior at time of exposure, life stage, 
depth) and can be difficult to predict (e.g., Southall et al., 2007, 
2021; Ellison et al., 2012). Based on what the available science 
indicates and the practical need to use a threshold based on a metric 
that is both predictable and measurable for most activities, NMFS 
typically uses a generalized acoustic threshold based on received level 
to estimate the onset of behavioral harassment. NMFS generally predicts 
that marine mammals are likely to be behaviorally harassed in a manner 
considered to be Level B harassment when exposed to underwater 
anthropogenic noise above the received root-mean-square sound pressure 
levels (RMS SPL) of 120 dB (referenced to 1 micropascal (re 1 [mu]Pa)) 
for continuous (e.g., vibratory pile-driving, drilling) and above the 
received RMS SPL 160 dB re: 1 [mu]Pa for non-explosive impulsive (e.g., 
seismic airguns) or intermittent (e.g., scientific sonar) sources 
(Table 7). Generally speaking, Level B harassment take estimates based 
on these behavioral harassment thresholds are expected to include any 
likely takes by TTS as, in most cases, the likelihood of TTS occurs at 
distances from the source less than those at which behavioral 
harassment is likely. TTS of a sufficient degree can manifest as 
behavioral harassment, as reduced hearing sensitivity and the potential 
reduced opportunities to detect important signals (conspecific 
communication, predators, prey) may result in changes in behavior 
patterns that would not otherwise occur.

       Table 7--Underwater Level B Harassment Acoustic Thresholds
                              [NMFS, 2005]
------------------------------------------------------------------------
                                                   Level B harassment
                 Source type                      threshold (RMS SPL)
------------------------------------------------------------------------
Continuous...................................  120 dB re 1 [mu]Pa.
Non-explosive impulsive or intermittent......  160 dB re 1 [mu]Pa.
------------------------------------------------------------------------

    Revolution Wind's construction activities include the use of 
continuous (e.g., vibratory pile driving) and intermittent (e.g., 
impact pile driving, HRG acoustic sources) sources, and, therefore, the 
120 and 160 dB re 1 [mu]Pa (rms) thresholds are applicable.
    Level A harassment--NMFS' Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0) 
(Technical Guidance, 2018) identifies dual criteria to assess auditory 
injury (Level A harassment) to five different marine mammal groups 
(based on hearing sensitivity) as a result of exposure to noise from 
two different types of sources (impulsive or non-impulsive). 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). Revolution Wind's proposed 
activities include the use of both impulsive and non-impulsive sources.
    These thresholds are provided in Table 8 below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS' 2018 Technical Guidance, which may be accessed at: 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

[[Page 79111]]



                                Table 8--Onset of Permanent Threshold Shift (PTS)
                                                   [NMFS 2018]
----------------------------------------------------------------------------------------------------------------
                                                         PTS onset thresholds * (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: Lp,0-pk,flat: 219   Cell 2: LE,p, LF,24h: 199 dB.
                                          dB; LE,p, LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3: Lp,0-pk,flat: 230   Cell 4: LE,p, MF,24h: 198 dB.
                                          dB; LE,p, MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: Lp,0-pk,flat: 202   Cell 6: LE,p, HF,24h: 173 dB.
                                          dB; LE,p,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: Lp,0-pk.flat: 218   Cell 8: LE,p,PW,24h: 201 dB.
                                          dB; LE,p,PW,24h: 185 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric 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 are recommended for consideration.
Note: Peak sound pressure level (L0-pk) has a reference value of 1 [mu]Pa, and weighted cumulative sound
  exposure level (LE,) has a reference value of 1Pa\2\s. In this Table, thresholds are abbreviated to be more
  reflective of International Organization for Standardization standards (ISO, 2017). The subscript ``flat'' is
  being included to indicate peak sound pressure are flat weighted or unweighted within the generalized hearing
  range of marine mammals (i.e., 7 Hz to 160 kHz). The subscript associated with cumulative sound exposure level
  thresholds indicates the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and
  PW pinnipeds) and that the recommended accumulation period is 24 hours. The weighted 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
  thresholds will be exceeded.

    Explosive sources--Based on the best available science, NMFS uses 
the acoustic and pressure thresholds indicated in Tables 9 and 10 to 
predict the onset of behavioral harassment, TTS, PTS, tissue damage, 
and mortality.

                            Table 9--PTS Onset, TTS Onset, for Underwater Explosives
                                                  [NMFS, 2018]
----------------------------------------------------------------------------------------------------------------
                                     PTS impulsive        TTS impulsive        Behavioral threshold (multiple
          Hearing group                thresholds           thresholds                  detonations)
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans....  Cell 1: Lpk,flat:    Cell 2: Lpk,flat:    Cell 3: LE,LF,24h: 163 dB.
                                   219 dB; LE,LF,24h:   213 dB; LE,LF,24h:
                                   183 dB.              168 dB.
Mid-Frequency (MF) Cetaceans....  Cell 4: Lpk,flat:    Cell 5: Lpk,flat:    Cell 6: LE,MF,24h: 165 dB.
                                   230 dB; LE,MF,24h:   224 dB; LE,MF,24h:
                                   185 dB.              170 dB.
High-Frequency (HF) Cetaceans...  Cell 7: Lpk,flat:    Cell 8: Lpk,flat:    Cell 9: LE,HF,24h: 135 dB.
                                   202 dB; LE,HF,24h:   196 dB; LE,HF,24h:
                                   155 dB.              140 dB.
Phocid Pinnipeds (PW)             Cell 10: Lpk,flat:   Cell 11: Lpk,flat:   Cell 12: LE,PW,24h: 165 dB.
 (Underwater).                     218 dB; LE,PW,24h:   212 dB; LE,PW,24h:
                                   185 dB.              170 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
  calculating PTS/TTS onset.
Note: Peak sound pressure (Lpk) has a reference value of 1 [mu]Pa, and cumulative sound exposure level (LE) has
  a reference value of 1[mu]Pa\2\s. In this Table, thresholds are abbreviated to reflect American National
  Standards Institute standards (ANSI, 2013). However, ANSI defines peak sound pressure 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 overall marine
  mammal 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
  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.

    Additional thresholds for non-auditory injury to lung and 
gastrointestinal (GI) tracts from the blast shock wave and/or onset of 
high peak pressures are also relevant (at relatively close ranges) as 
UXO/MEC detonations, in general, have potential to result in mortality 
and non-auditory injury (Table 10). Lung injury criteria have been 
developed by the U.S. Navy (DoN (U.S. Department of the Navy) 2017a) 
and are based on the mass of the animal and the depth at which it is 
present in the water column due to blast pressure. This means that 
specific decibel levels for each hearing group are not provided and 
instead the criteria are presented as equations that allow for 
incorporation of specific mass and depth values. The GI tract injury 
threshold is based on peak pressure. The modified Goertner equations 
below represent the potential onset of lung injury and GI tract injury 
(Table 10).

                                 Table 10--Lung and G.I. Tract Injury Thresholds
                                                   [DoN, 2017]
----------------------------------------------------------------------------------------------------------------
                                   Mortality (severe    Slight lung injury
          Hearing group              lung injury) *             *                     G.I. tract injury
----------------------------------------------------------------------------------------------------------------
All Marine Mammals..............  Cell 1: Modified     Cell 2: Modified     Cell 3: Lpk,flat: 237 dB.
                                   Goertner model;      Goertner model;
                                   Equation 1.          Equation 2.
----------------------------------------------------------------------------------------------------------------
* Lung injury (severe and slight) thresholds are dependent on animal mass (Recommendation: Table C.9 from DoN
  (2017) based on adult and/or calf/pup mass by species).

[[Page 79112]]

 
Note: Peak sound pressure (Lpk) has a reference value of 1 [mu]Pa. In this Table, thresholds are abbreviated to
  reflect American National Standards Institute standards (ANSI, 2013). However, ANSI defines peak sound
  pressure 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 overall marine mammal generalized hearing range.
Modified Goertner Equations for severe and slight lung injury (pascal-second):
Equation 1: 103M \1/3\(1 + D/10.1)\1/6\ Pa-s.
Equation 2: 47.5M \1/3\(1 + D/10.1)\1/6\ Pa-s.
M animal (adult and/or calf/pup) mass (kg) (Table C.9 in DoN, 2017).
D animal depth (meters).

    Below, we discuss the acoustic modeling, marine mammal density 
information, exposure estimate, and requested take methodologies for 
each of Revolution Wind's proposed construction activities. NMFS has 
carefully considered all information and analysis presented by the 
applicant as well as all other applicable information and, based on the 
best available science, concurs that the applicant's estimates of the 
types and amounts of take for each species and stock are complete and 
accurate.

Marine Mammal Density and Occurrence

    In this section we provide the information about the presence, 
density, or group dynamics of marine mammals that will inform the take 
calculations. As noted above, depending on the species and activity 
type and as described in the take estimation section for each activity 
type, take estimates may be based on the Roberts et al. (2022) density 
estimates, marine mammal monitoring results from HRG surveys, or 
average group sizes.
    Regarding habitat-based marine mammal density models for the 
project area, newer density models became available after Revolution 
Wind submitted their application (deemed Adequate & Complete on 
February 28, 2022) and Revolution Wind subsequently provided revised 
take estimates based on the updated density models, where appropriate. 
Specifically, in both the original application and the revised take 
estimates, the densities of marine mammals (individuals per unit area) 
expected to occur in the activity areas were calculated from habitat-
based density models produced by the Duke University Marine Geospatial 
Ecology Laboratory and the Marine-life Data and Analysis Team (https://seamap.env.duke.edu/models/Duke/EC/ EC/), which represent the best 
available science regarding marine mammal occurrence in the project 
area. Within the original version of the application (https://www.fisheries.noaa.gov/national/marine-mammal-protection/apply-incidental-take-authorization), different densities were used for the 
WTG and OSS foundation installation (Roberts et al., 2016, 2017, 2018, 
2020); the export cable landfall (Roberts et al., 2016, 2017, 2018, 
2021); the UXO/MEC detonations (Roberts et al., 2016, 2017, 2018, 
2021); and the site characterization surveys (Roberts et al., 2016, 
2017, 2018, 2021), during both the construction and operation phases.
    On June 20, 2022, the Duke Marine Geospatial Ecology Laboratory 
released a new, and more comprehensive, set of marine mammal density 
models for the area along the East Coast of the United States (Roberts 
et al., 2016; Roberts and Halpin, 2022). The differences between the 
new density data and the older data necessitated the use of updated 
marine mammal densities and, subsequently, revised marine mammal 
exposure and take estimates. Revolution Wind was able to use the same 
density dataset for all of its activities (Roberts et al., 2016; 
Roberts and Halpin, 2022). Revolution Wind also incorporated updates to 
how the density data were selected from the model output for each 
activity, based on discussions with NMFS. For all activities, the width 
of the perimeter around the activity area used to select density data 
is now based on the largest exposure range (typically the Level B 
range) applicable to that activity and then rounded up to the nearest 
5-km increment, (which reflects the spatial resolution of the Roberts 
and Halpin (2022) density models). For example, if the largest exposure 
range was 7.1 km, a 10-km perimeter around the activity area was 
created and used to select densities for all species from the Roberts 
and Halpin (2022) model output. All of this information was provided by 
Revolution Wind to NMFS as a memo (referred to as the Updated Density 
and Take Estimation Memo) on August 19, 2022, after continued 
discussion between Revolution Wind and NMFS, and NMFS has considered it 
in this analysis. The Updated Density and Take Estimation Memo was made 
public on NMFS' website on August 26, 2022 (https://www.fisheries.noaa.gov/action/incidental-take-authorization-revolution-wind-llc-construction-revolution-wind-energy).
    In adopting the information presented in the Updated Density and 
Take Estimation Memo, NMFS has ensured that the tables and figures 
reflect the latest marine mammal habitat-based density models released 
by Roberts and Halpin on June 20, 2022.
    Immediately below, we describe observational data from monitoring 
reports and average group size information, both of which are 
appropriate to inform take estimates for certain activities or species 
in lieu of density estimates. As noted above, the density and 
occurrence information type resulting in the highest take estimate was 
used, and the explanation and results for each activity type are 
described in the specific activity sub-sections in the Modeling and 
Take Estimation section.
    For some species, observational data from PSOs aboard HRG and 
geotechnical (GT) survey vessels indicate that the density-based 
exposure estimates may be insufficient to account for the number of 
individuals of a species that may be encountered during the planned 
activities. PSO data from HRG and GT surveys conducted in the area 
surrounding the Revolution Wind lease area and RWEC route from October 
2018 through February 2021 (AIS-Inc., 2019; Bennett, 2021; Stevens et 
al., 2021; Stevens and Mills, 2021) were analyzed to determine the 
average number of individuals of each species observed per vessel day. 
For each species, the total number of individuals observed (including 
the ``proportion of unidentified individuals'') was divided by the 
number of vessel days during which observations were conducted in 2018-
2021 HRG surveys (470 vessel days) to calculate the number of 
individuals observed per vessel day, as shown in the final columns of 
Tables 7a and 7b in the Updated Density and Take Estimation Memo.
    For other less-common species, the predicted densities from Roberts 
and Halpin (2022) are very low and the resulting density-based exposure 
estimate is less than a single animal or a typical group size for the 
species. In such cases, the mean group size was considered as an 
alternative to the density-based or PSO data-based take estimates to 
account for potential impacts on a group during an activity. Mean group 
sizes for each species were calculated from recent aerial and/or 
vessel-based surveys as shown in Table 11.

[[Page 79113]]



               Table 11--Mean Group Sizes of Species for Which Incidental Take Is Being Requested
----------------------------------------------------------------------------------------------------------------
                                                              Mean group
             Species               Individuals   Sightings       size                     Source
----------------------------------------------------------------------------------------------------------------
Mysticetes:
    Blue Whale *.................            3            3          1.0  Palka et al. (2017).
    Fin Whale *..................          155           86          1.8  Kraus et al. (2016).
    Humpback Whale...............          160           82          2.0  Kraus et al. (2016).
    Minke Whale..................          103           83          1.2  Kraus et al. (2016).
    North Atlantic Right Whale *.          145           60          2.4  Kraus et al. (2016).
    Sei Whale *..................           41           25          1.6  Kraus et al. (2016).
Odontocetes:
    Atlantic Spotted Dolphin.....        1,334           46         29.0  Palka et al. (2017).
    Atlantic White-Sided Dolphin.          223            8         27.9  Kraus et al. (2016).
    Bottlenose Dolphin...........          259           33          7.8  Kraus et al. (2016).
    Common Dolphin...............        2,896           83         34.9  Kraus et al. (2016).
    Harbor Porpoise..............          121           45          2.7  Kraus et al. (2016).
    Pilot Whales.................          117           14          8.4  Kraus et al. (2016).
    Risso's Dolphin..............        1,215          224          5.4  Palka et al. (2017).
    Sperm Whale*.................          208          138          1.5  Palka et al. (2017).
Pinnipeds:
    Seals (Harbor and Gray)......          201          144          1.4  Palka et al. (2017).
----------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.

    The estimated exposure and take tables for each activity present 
the density-based exposure estimates, PSO-date derived take estimate, 
and mean group size for each species. The amount of Level B harassment 
take requested is based on the largest of these three values, which is 
considered the maximum amount of take by Level B harassment that is 
reasonably likely to occur. As mentioned previously, the amount of take 
by Level A harassment requested is based strictly on density-based 
exposure modeling results.

Modeling and Take Estimation

    Revolution Wind estimated potential density-based exposures in two 
separate ways, depending on the activity. For WTG and OSS monopile 
foundation installation, sophisticated sound and animal movement 
modeling was conducted to more accurately account for the movement and 
behavior of marine mammals and their exposure to the underwater sound 
fields produced during impact pile driving, as described below. For 
landfall construction activities, HRG surveys, and in-situ UXO/MEC 
disposal (i.e., detonation), takes are estimated by multiplying the 
expected densities of marine mammals in the activity area(s) by the 
area of water likely to be ensonified above harassment threshold levels 
in a single day (24-hour period). The result is then multiplied by the 
number of days on which the activity is expected to occur, resulting in 
a density-based exposure estimate for each activity. Again, in some 
cases, these results directly inform the take estimates while, in other 
cases, adjustments are made based on monitoring results or average 
group size.
    Below, we describe, in detail, the approach used to estimate take, 
in consideration of the acoustic thresholds and appropriate marine 
mammal density and occurrence information described above for each of 
the four different activities (WTG/OSS foundation installation, UXO/MEC 
detonation, landfall construction activities, and HRG surveys). The 
activity-specific exposure estimates (as relevant to the analysis) and 
activity-specific take estimates are also presented, alongside the 
combined totals annually, across the entire 5-year proposed project, 
and as the maximum take of marine mammals that could occur within any 
one year.
WTG and OSS Monopile Foundation Installation
    Here, for WTG and OSS monopile foundation installation, we describe 
the models used to predict sound propagation and animal movement and 
the inputs to those models, the density and/or occurrence information 
used to support the take estimates for this activity type, and the 
resulting acoustic and exposure ranges, exposures, and takes proposed 
for authorization.
    As indicated previously, Revolution Wind initially proposed to 
install up to 100 WTGs and 2 OSSs in the RWF (i.e., a maximum of 102 
foundations) but has recently informed NMFS that, due to installation 
feasibility issues, they would be removing 21 turbine locations from 
their project, reducing the total number of turbines from 100 to 79. 
Therefore, in this section, we present the acoustic and exposure for 
Revolution Wind's proposal of up to 79 WTF foundations and 2 OSS 
foundations.
    The full installation parameters for each size monopile are 
described below. The two impact pile driving installation acoustic 
modeling scenarios are:
    (1) 7/12-m diameter WTG monopile foundation: A total of 10,740 
hammer strikes per pile modeled over 220 minutes (3.7 hours); and,
    (2) 7/15-m diameter OSS foundation: A total of 11,564 hammer 
strikes per pile modeled over 380 minutes (6.3 hours).
    Representative hammering schedules (Table 12), including increasing 
hammer energy with increasing penetration depth, were modeled because 
maximum sound levels usually occur during the last stage of impact pile 
driving, where the greatest resistance is typically encountered (Betke, 
2008). The hammering schedule includes a soft start, or a period of 
hammering at a reduced hammer energy (relative to full operating 
capacity). Sediment types with greater resistance (e.g., gravel versus 
sand) require hammers that deliver higher energy strikes and/or an 
increased number of strikes relative to installations in softer 
sediment. The project area includes a predominantly sandy bottom 
habitat, which is considered a softer sediment, based on HRG survey 
data collected in the lease area (see Appendices X1 and X2 of 
Revolution Wind's 2022 Construction and Operations Plan; Revolution 
Wind, 2022).

[[Page 79114]]



                         Table 12--Hammer Energy Schedules for Monopile Installation \1\
----------------------------------------------------------------------------------------------------------------
            Monopile foundations (7/12-m diameter)                      OSS foundations (7/1-m diameter)
----------------------------------------------------------------------------------------------------------------
                      Hammer: IHC S-4000                                       Hammer: IHC S-4000
----------------------------------------------------------------------------------------------------------------
                                  Strike     Pile penetration     Energy level       Strike     Pile penetration
 Energy level (kilojoule, kJ)     count         depth (m)       (kilojoule, kJ)      count           depth
----------------------------------------------------------------------------------------------------------------
1,000........................        1,705                0-6              1,000          954                0-5
2,000........................        3,590               6-24              2,000        2,944               5-17
3,000........................        2,384              24-36              3,000        4,899              17-36
4,000........................        3,061              36-50              4,000        2,766              36-50
                              ----------------------------------------------------------------------------------
    Total....................       10,740                 50  .................       11,563                 50
----------------------------------------------------------------------------------------------------------------
\1\ Modeled strike rate (min-1) for both schedules = 50.

    Revolution Wind would install monopiles vertically to a penetration 
depth of 50 m; therefore, the model includes this assumption. While 
pile penetration depth among the foundation positions might vary 
slightly, this value was chosen as a reasonable penetration depth for 
the purposes of acoustic modeling based on Revolution Wind's 
engineering designs. All modeling was performed assuming that only one 
pile is driven at a time (as Revolution Wind would not conduct 
concurrent monopile installations), up to three WTG foundations would 
be installed per day, and no more than one OSS foundation would be 
installed per day.
    Additional modeling assumptions based on Revolution Wind's 
engineering designs for monopile installation were as follows:

 Both WTG and OSS
    [cir] Impact pile driver: IHC S-4000 (4000 kilojoules (kJ) rated 
energy; 1977 kilonewtons (kN) ram weight)
    [cir] Helmet weight: 3234 kN
 WTG only
    [cir] Tapered 7/12-m steel cylindrical piling with 16-cm thick wall
    [cir] Pile length: 110 m
 OSS only
    [cir] Tapered 7/15-m cylindrical piling with 20-cm thick wall
    [cir] Pile length: 120 m

    Sound fields produced during monopile installation were estimated 
by first computing the force at the top of each pile associated with 
typical hammers using the GRLWEAP 2010 wave equation model (GRLWEAP, 
Pile Dynamics 2010), which produced forcing functions. The resulting 
forcing functions were used as inputs to JASCO Applied Sciences' 
(JASCO) Pile Driving Source Model (PDSM) to compute the monopile 
vibrations (i.e., sounds) caused by hammer impact. To accurately 
calculate propagation metrics of an impulsive sound, a time-domain 
representation of the pressure wave in the water was used. To model the 
sound waves associated with the monopile vibration in an acoustic 
propagation model, the monopiles are represented as vertical arrays of 
discrete point sources. These discrete sources are distributed 
throughout the length of the monopile below the sea surface and into 
the sediment with vertical separation of 3 m. The length of the 
acoustic source is adjusted for the site-specific water depth and 
penetration at each energy level, and the section length of the 
monopile within the sediment is based on the monopile hammering 
schedule (Table 12). Pressure signatures for the point sources are 
computed from the particle velocity at the monopile wall up to a 
maximum frequency of 2,048 Hz. This frequency range is suitable because 
most of the sound energy generated by impact hammering of the monopiles 
is below 1 kHz. The results of this source level modeling were then 
incorporated into acoustic propagation models. The modeled source 
spectra are provided in Figures 10-14 of Appendix A of Revolution 
Wind's application (Kusel et al., 2021).
    Underwater sound propagation (i.e., transmission loss) at 
frequencies of 10 Hz to 2 kHz was predicted with JASCO's Marine 
Operations Noise Model (MONM) and full-wave Range-dependent Acoustic 
Model (RAM) parabolic equation (PE) model (FWRAM). MONM computes 
acoustic propagation via a wide-angle PE solution to the acoustic wave 
equation (Collins, 1993) based on a version of the U.S. Naval Research 
Laboratory's RAM, which has been modified to account for a solid seabed 
(Zhang and Tindle, 1995; Kusel et al., 2021). The PE method has been 
extensively benchmarked and is widely employed in the underwater 
acoustics community (Collins et al., 1996) and has been validated 
against experimental data in several underwater acoustic measurement 
programs by JASCO. MONM incorporates the following site-specific 
environmental properties: a bathymetric grid of the modeled area, 
underwater sound speed as a function of depth, and seabed type (a 
geoacoustic profile based on the overall stratified composition of the 
seafloor).
    For impulsive sounds from impact pile driving, time-domain 
representations of the sounds generated in the water are required for 
calculating SPL and peak pressure level. Synthetic pressure waveforms 
were computed using FWRAM, which is a time-domain acoustic model based 
on the same wide-angle PE algorithm as MONM. Unlike MONM, FWRAM 
computes pressure waveforms via Fourier synthesis of the modeled 
acoustic transfer function in closely spaced frequency bands (Kusel et 
al., 2021). FWRAM computes these synthetic pressure waveforms versus 
range and depth for range-varying marine acoustic environments, 
utilizing the same environmental inputs as MONM (bathymetry, water 
sound speed profile, and seabed geoacoustic profile). Because the 
monopile is represented as a linear array and FWRAM employs the array 
starter method to accurately model sound propagation from a spatially 
distributed source (MacGillivray and Chapman, 2012), using FWRAM 
ensures accurate characterization of vertical directivity effects in 
the near-field zone.
    At frequencies less than 2 kHz, MONM computes acoustic propagation 
via a wide-angle PE solution to the acoustic wave equation based on a 
version of the U.S. Naval Research Laboratory's RAM modified to account 
for an elastic seabed. MONM-RAM incorporates bathymetry, underwater 
sound speed as a function of depth, and a geo-acoustic 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

[[Page 79115]]

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 modeling component incorporates bathymetry and 
underwater sound speed as a function of depth with a simplified 
representation of the sea bottom, as sub-bottom 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).
    Two WTG and three OSS locations within the RWF were selected for 
acoustic modeling to provide representative propagation conditions and 
sound fields (see Figure 2 in Kusel et al., 2021). The two WTG 
locations were selected to represent the relatively shallow (36.8 m) 
northwest section of the RWF to the somewhat deeper (41.3 m) southeast 
section. The three potential OSS locations (of which only two would be 
used to install the two OSS foundations) selected occupy similar water 
depths (33.7, 34.2, and 34.4 m). The acoustic propagation fields 
applied to exposure modeling (described below) were those 
conservatively based on the WTG (1 of 2) and OSS (1 of 3) locations 
resulting in the largest fields. In addition to bathymetric and seabed 
geoacoustic data specific to the specific locations within the RWF, 
acoustic propagation modeling was conducted separately for ``summer'' 
(April through November) and ``winter'' (December through March) using 
representative sound velocity profiles for those timeframes (based on 
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.
    The estimated pile driving schedules (Table 12) were used to 
calculate the SEL sound fields at different points in time during both 
WTG and OSS monopile foundation installation. Models are more efficient 
at estimating SEL than SPLrms. Therefore, conversions may 
sometimes be necessary to derive the corresponding SPLrms. 
Acoustic 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 was used to develop azimuth-, 
range-, and depth-dependent conversion factors (Kusel et al., 2021). 
These conversion factors were used to calculate the broadband 
SPLrms from the broadband SEL prediction.
    Revolution Wind modeled both acoustic ranges and exposure ranges. 
Acoustic ranges represent the distance to a harassment threshold based 
on sound propagation through the environment (i.e., independent of any 
receiver) while exposure range represents the distance at which an 
animal can accumulate enough energy to exceed a Level A harassment 
threshold in consideration of how it moves through the environment 
(i.e., using movement modeling). In both cases, the 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 exposure and 
acoustic ranges to Level A harassment and Level B harassment isopleths. 
However, the ranges to a threshold typically differ among radii from a 
source, and also might not be continuous along a radii 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, 
R95%, was chosen to identify the area over which 
marine mammals may be exposed above a given threshold, because, 
regardless of the shape of the maximum-over-depth footprint, the 
predicted range encompasses at least 95 percent of the horizontal area 
that would be exposed to sound at or above the specified threshold. The 
difference between Rmax and R95% 
depends on the source directivity and the heterogeneity of the acoustic 
environment. R95% excludes ends of protruding 
areas or small isolated acoustic foci not representative of the nominal 
ensonified zone. For purposes of calculating take by Level A harassment 
and Level B harassment, Revolution Wind applied R95% 
exposure ranges (described below), not acoustic ranges, to estimate 
take and determine mitigation distances for the reasons described 
below.
    In order to best apply the (SELcum) harassment 
thresholds for PTS, it is necessary to consider animal movement, as the 
results are based on how sound moves through the environment between 
the source and the receiver. Applying animal movement and behavior 
within the modeled noise fields provides the exposure range, which 
allows for a more realistic indication of the distances at which PTS 
acoustic thresholds are reached that considers the accumulation of 
sound over different durations (note that in all cases the distance to 
the peak threshold is less than the SEL-based threshold).
    As described in Section 2.6 of Appendix A of Revolution Wind's ITA 
application, for modeled animals that have received enough acoustic 
energy to exceed a given Level A harassment 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 
(ER95%)). The ER95% ranges 
are species-specific rather than categorized only by functional hearing 
group, which allows for the incorporation of more species-specific 
biological parameters (e.g., dive durations, swim speeds, etc.) for 
assessing the impact ranges in the model. Furthermore, because these 
ER95% ranges are species-specific, they can be 
used to develop mitigation monitoring or shutdown zones.
    Sound exposure modeling, like JASCO's Animal Simulation Model 
Including Noise Exposure (JASMINE), involves the use of a three-
dimensional computer simulation in which simulated animals (animats) 
move through the modeled marine environment over time in ways that are 
defined by the known or assumed movement patterns for each species 
derived from visual observation, animal borne tag, or other similar 
studies. 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

[[Page 79116]]

with many animats and randomized starting positions. The probability of 
an 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 sound field produced by the activity, in this case impact pile 
driving, is then added to the modeling environment at the location and 
for the duration of time anticipated for one or more pile 
installations. At each time step in the simulation, each animat records 
the received sound levels at its location resulting in a sound exposure 
history for each animat. These exposure histories are then analyzed to 
determine whether and how many animats (i.e., simulated animals) were 
exposed above harassment threshold levels. Finally, the density of 
animats used in the modeling environment, which is usually much higher 
than the actual density of marine mammals in the activity area so that 
the results are more statistically robust, is compared to the actual 
density of marine mammals anticipated to be in the project area.
    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 densities 
for an animal 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-percent chance that 
one animat will exceed a relevant threshold during the project, or 
equivalently, if the simulation were re-run ten times, one of the ten 
simulations would result in an animat exceeding the threshold. 
Similarly, a mean number prediction of 33.11 animats can be interpreted 
as re-running the simulation where the number of animats exceeding the 
threshold may differ in each simulation but the mean number of animats 
over all of the simulations is 33.11. A portion of an individual marine 
mammal cannot be taken during a project, so it is common practice to 
round mean number animat exposure values to integers using standard 
rounding methods. However, for low-probability events it is more 
precise to provide the actual values. For this reason, mean number 
values are not rounded. A more detailed description of this method is 
available in Appendix A of Revolution Wind's application.
    For Revolution Wind's proposed project, JASMINE animal movement 
model was used to predict both the ER95% ranges 
and the probability of marine mammal exposure to impact pile driving 
sound generated by monopile installation. Sound fields generated by the 
acoustic propagation modeling described above 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. 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. 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 Appendix A of 
the ITA application.
    The mean numbers of animats that may be exposed to noise exceeding 
acoustic thresholds were calculated based on installation of 1, 2, or 3 
WTG foundations and, separately, 1 or 2 OSS foundations in 24 hours. 
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 SPLpeak and 
SPLcum were calculated for each species based on the 
corresponding acoustic criteria. Once an animat is taken within a 24-
hour period, the model does not allow it to be taken a second time in 
that same period but rather resets the 24-hour period on a sliding 
scale across 7 days of exposure. For Level A harassment, an individual 
animat's exposure levels are summed over that 24-hour period to 
determine its total received energy, and then compared to the 
appropriate PTS threshold. Takes by behavioral disturbance are 
predicted when an animat is modeled to come within the area ensonified 
by sound levels exceeding the corresponding Level B harassment 
thresholds. Please 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 A of the ITA application for more details on 
the JASMINE modeling methodology.
    Revolution Wind would employ a noise abatement system during all 
impact pile driving of monopiles. Noise abatement systems, such as 
bubble curtains, are sometimes used to decrease the sound levels 
radiated from a source. In modeling the sound fields produced by 
Revolution Wind's proposed activities, hypothetical broadband 
attenuation levels of 0 dB, 6 dB, 10 dB, 12 dB, 15 dB, and 20 dB for 
were modeled to gauge effects on the ranges to thresholds given these 
levels of attenuation. Although six attenuation levels were evaluated, 
Revolution Wind anticipates that the noise abatement system ultimately 
chosen will be capable of reliably reducing source levels by 10 dB; 
therefore, modeling results assuming 10-dB attenuation are carried 
forward in this analysis. Recently reported in situ measurements during 
installation of large monopiles (approximately 8 m) for more than 150 
WTGs in comparable water depths (greater than 25 m) and conditions in 
Europe indicate that attenuation levels of 10 dB are readily achieved 
(Bellmann, 2019; Bellmann et al., 2020) using single big bubble 
curtains (BBCs) as a noise abatement system. Designed to gather 
additional data regarding the efficacy of BBCs, the Coastal Virginia 
Offshore Wind (CVOW) pilot project systematically measured noise levels 
resulting from the impact driven installation of two 7.8 m monopiles, 
one with a noise abatement 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 abatement 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 harassment and Level B harassment 
isopleths. The estimated distances for the monopile with the dBBC were 
more than 90 percent (Level A) and 74 percent (Level B) smaller than 
those

[[Page 79117]]

estimated for the unmitigated pile (CVOW). Modeling results assuming 
different amounts of attenuation can be found in Appendix A of 
Revolution Wind's ITA application. Additional information related to 
Revolution Wind's proposed use of noise abatement systems is provided 
in the Proposed Mitigation, and Proposed Monitoring and Reporting 
sections.
    As described more generally above, updated Roberts et al. (2022) 
habitat-based marine mammal density models provided the densities used 
to inform and scale the marine mammal exposure estimates produced by 
the JASMINE model. For monopile installation, specifically, mean 
monthly densities for all species were calculated by first selecting 
density data from 5 x 5 km (3.1 x 3.1 mile) grid cells (Roberts et al., 
2016; Roberts and Halpin, 2022) both within the lease area and out to 
10 km (6.2 mi) from the perimeter of the lease area. This is a 
reduction from the 50 km (31 mi) perimeter used in the ITR application. 
The relatively large area selected for density estimation encompasses 
and extends approximately to the largest estimated exposure acoustic 
range (ER95%) to the isopleth corresponding to 
Level B harassment, assuming no noise attenuation) (see Tables 19 and 
20 of the ITA application) for all hearing groups using the unweighted 
threshold of 160 dB re 1 [mu]Pa (rms). Please see Figure 6 in 
Revolution Wind's Updated Density and Take Estimation Memo for an 
example of a density map showing Roberts and Halpin (2022) density grid 
cells overlaid on a map of the RWF.
    Although there is some uncertainty in the monopile foundation 
installation schedule, Revolution Wind anticipates that it would occur 
over approximately one month provided good weather conditions and no 
unexpected delays. The exposure calculations were thus conducted using 
marine mammal densities from the month with the highest average density 
estimate for each species, based on the assumption that all 79 WTG and 
two OSS foundations would be installed in the highest density month (78 
WTG monopile (3 per day for 26 days), 1 WTG monopile (1 per day for 1 
day) and 2 OSS monopile foundations (1 per day for 2 days)). Due to 
differences in the seasonal migration and occurrence patterns, the 
month selected differs for each species. The estimated monthly density 
of seals provided in Roberts and Halpin (2022) includes all seal 
species present in the region as a single guild. To split the resulting 
``seal'' density-based exposure estimate by species (harbor and gray 
seals), the estimate was multiplied by the proportion of the combined 
abundance attributable to each species. Specifically, the SAR 
Nbest abundance estimates (Hayes et al., 2021) for the two 
species (gray seal = 27,300, harbor seal = 61,336; total = 88,636) were 
summed and divided the total by the estimate for each species to get 
the proportion of the total for each species (gray seal = 0.308; harbor 
seal = 0.692). The total estimated exposures value based on the pooled 
seal density provided by Roberts and Halpin (2022) was then multiplied 
by these proportions to get the species-specific exposure estimates. 
Monthly densities were unavailable for pilot whales, so the annual mean 
density was used instead. The blue whale density was considered too low 
to be carried into exposure estimation so the amount of blue whale take 
Revolution Wind requested (see Estimated Take) is instead based on 
group size. Table 13 shows the maximum average monthly densities by 
species that were incorporated in exposure modeling to obtain 
conservative exposure estimates.

 Table 13--Maximum Average Monthly Marine Mammal Densities (Animals per
      Km\2\) Within and Around the Lease Area Out to 10 Km (6.2 Mi)
------------------------------------------------------------------------
                                                Monopile foundations
          Marine mammal  species           -----------------------------
                                                   Highest density
------------------------------------------------------------------------
Blue whale \1\ \2\........................
Fin whale \1\.............................  0.0029 (July).
Humpback whale............................  0.0021 (May).
Minke whale...............................  0.0174 (May).
North Atlantic right whale \1\............  0.0026 (December).
Sei whale \1\.............................  0.0013 (May).
Atlantic spotted dolphin..................  0.0005 (October).
Atlantic white-sided dolphin..............  0.0174 (May).
Bottlenose dolphin........................  0.0091 (August).
Common dolphin............................  0.0743 (December)
Harbor porpoise...........................  0.0515 (December).
Pilot whales \3\..........................  0.0007 (annual).
Risso's dolphin...........................  0.0017 (December).
Sperm whale \1\...........................  0.0004 (August).
Seals (Harbor and Gray)...................  0.2225 (May).
------------------------------------------------------------------------
\1\ Listed as Endangered under the Endangered Species Act.
\2\ Exposure modeling for the blue whale was not conducted because
  impacts to those species approach zero due to their low predicted
  densities in the Project; therefore, were excluded from all
  quantitative analyses and tables based on modeling results.
\3\ Roberts and Halpin (2022) does not distinguish between short- and
  long-finned pilot whales, thus the pooled density provided represents
  both species.

    For the exposure analysis, it was assumed that a maximum of three 
WTG monopile foundations may be driven in 24 hours, presuming 
installations are permitted to continue in darkness. It is unlikely 
that this installation rate would be consistently possible throughout 
the RWF construction phase, but this scenario was considered to have 
the greatest potential impact on marine mammals and was, therefore, 
carried forward into take estimation. Exposure ranges 
(ER95%) to the Level A SELcum 
thresholds and Level B SPLrms threshold resulting from 
animal exposure modeling for installation of one (for comparative 
purposes) or three (assumed for exposure modeling) WTG foundations and 
one OSS foundation per day (assumed for exposure modeling), assuming 
10-dB of attenuation, for the summer (when Revolution Wind intends to 
install the majority of monopile foundations) and winter are shown in 
Tables 14 and 15. Any activities conducted in the winter (December) 
would utilize monitoring and mitigation measures based on the exposure 
ranges (ER95%) calculated using winter sound 
speed profiles. Revolution Wind does not plan to install two OSS 
foundations in a single day, therefore, modeling results are provided 
for installation of a single OSS foundation per day. Exposure ranges 
were also modeled assuming installation of two WTG foundations per day 
(not shown here); see Appendix A of Revolution Wind's ITA application 
for those results. Meaningful differences (greater than 500 m) between 
species within the same hearing group occurred for low-frequency 
cetaceans, so exposure ranges are shown separately for those species 
(Tables 14 and 15). For mid-frequency cetaceans and pinnipeds, the 
largest value among the species in the hearing group was selected to be 
included in Tables 14 and 15.

[[Page 79118]]



Table 14--Exposure Ranges\1\ (ER95%) to Level A (SELcum) Thresholds for Installation of One and Three 7/12-m WTG Monopiles (10,740 Strikes) or One 7/15-
                                   m OSS Monopile (11,564 Strikes) During Summer and Winter Assuming 10-dB Attenuation
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Range (km)
---------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                        WTG monopile  1 pile/    WTG monopile  3    OSS monopile  1 pile/
                                                                    SELcum  threshold            day                piles/day                day
                          Hearing group                                  (dB re 1      -----------------------------------------------------------------
                                                                   [mu]Pa\2\[middot]s)    Summer     Winter     Summer     Winter     Summer     Winter
--------------------------------------------------------------------------------------------------------------------------------------------------------
Low-frequency....................................................                  183  .........  .........  .........  .........  .........  .........
Fin Whale *......................................................  ...................       2.15       3.53       2.23       4.38       1.57       2.68
Humpback Whale...................................................  ...................       2.46       4.88       2.66       6.29       1.79       3.56
Minke Whale......................................................  ...................       1.32       3.03       1.51       3.45       0.94       1.81
North Atlantic Right Whale *.....................................  ...................       1.85       3.42       1.93       3.97       1.25       2.66
Sei Whale *......................................................  ...................       1.42       2.82       1.81       3.67       1.22       2.05
Mid-frequency....................................................                  185          0       0.01       0.02       0.02          0          0
High-frequency...................................................                  155       1.28       2.29       1.34       2.33       0.83       1.25
Phocid pinnipeds.................................................                  185        0.6       0.73       0.44       0.81       0.37       0.37
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.
\1\ Exposure ranges are a result of animal movement modeling.


 Table 15--Exposure Ranges \1\ (ER95%) to the Level B (SPLrms) Isopleth for Installation of One and Three 7/12-m
          WTG Monopiles or One 7/15-m OSS Monopile During Summer and Winter Assuming 10-dB Attenuation
----------------------------------------------------------------------------------------------------------------
                                                   Range (km)
-----------------------------------------------------------------------------------------------------------------
                                                WTG monopile  1 pile/    WTG monopile  3    OSS monopile  1 pile/
                                                         day                piles/day                day
                 Hearing group                 -----------------------------------------------------------------
                                                  Summer     Winter     Summer     Winter     Summer     Winter
----------------------------------------------------------------------------------------------------------------
Fin Whale *...................................       3.72       4.05       3.76       4.09       3.62       3.88
Humpback Whale................................       3.75       4.15       3.72       4.11       3.61       3.87
Minke Whale...................................       3.71       4.07       3.63       4.07       3.56       3.84
North Atlantic Right Whale *..................       3.70       4.06       3.67       3.95       3.51       3.75
Sei Whale *...................................       3.66       4.11       3.67       4.02       3.58       3.92
Mid-frequency.................................       3.69       4.07       3.67       4.03       3.63       3.81
High-frequency................................       3.71       4.00       3.62       4.03       3.50       3.91
Phocid pinnipeds..............................       3.79       4.21       3.80       4.23       3.75       4.02
----------------------------------------------------------------------------------------------------------------
* Listed as Endangered under the Endangered Species Act.
\1\ Exposure ranges are a result of animal movement modeling.

    As mentioned previously, acoustic ranges 
(R95%) were also modeled. These distances were 
not applied to exposure estimation, but were used to define the Level B 
harassment zones for all species (see Proposed Mitigation) for WTG and 
OSS foundation installation in summer and winter (in parentheses):

 WTG monopile: 3,833 m (4,271 m)
 OSS monopile: 4,100 m (4, 698 m)

    Finally, the results of marine mammal exposure modeling, assuming 
10-dB attenuation, for installation of 79 WTG and 2 OSS monopile 
foundations are shown in columns 2 and 3 of Table 16; these values 
assume that all 81 foundations (79 WTGs and 2 OSSs) would be installed 
in a single year, and form the basis for the amount of take incidental 
to construction of the RWF requested by Revolution Wind and proposed 
for authorization by NMFS. Columns 4 and 5 show what the take estimates 
would be if the PSO data or average group size, respectively, were used 
to inform the take by Level B harassment in lieu of the density and 
exposure modeling. The last column represents the take that NMFS is 
proposing for authorization, which is based on the highest of the three 
estimates shown in columns 3, 4, and 5. The Level A exposure estimates 
shown in Table 16 are based only on the Level A SELcum 
threshold and associated exposure ranges (Table 14), as the very short 
distances to isopleths based on the Level A SPLpk thresholds 
(Table 14 in the ITA application) resulted in no meaningful likelihood 
of take from exposure to those sound levels. The Level B exposure 
estimates shown in Table 16 are based on the exposure ranges resulting 
from sound exposure modeling using the unweighted 160 dB 
SPLrms criterion (Table 15).

Table 16--Estimated Take, by Level A Harassment and Level B Harassment, for 79 (7/12-m) WTG and Two (7/15-m) OSS
                          Monopile Foundation Installations Assuming 10-dB Attenuation
----------------------------------------------------------------------------------------------------------------
                                    Exposure modeling take
                                         estimates \1\
             Species             ----------------------------  PSO data  take    Mean  group     Maximum annual
                                     Level A       Level B        estimate          size          level B take
                                    (SPLcum)      (SPLrms)
----------------------------------------------------------------------------------------------------------------
Blue Whale *....................           N/A           N/A  ...............             1.0                  1
Fin Whale *.....................           6.4          14.9             15.8             1.8                 16

[[Page 79119]]

 
Humpback Whale..................           6.5          11.5             47.1             2.0                 48
Minke Whale.....................          60.9         191.2              5.8             1.2                192
North Atlantic Right Whale *....          17.5          21.6              1.4             2.4                 22
Sei Whale *.....................           2.5           7.8              0.4             1.6                  8
Atlantic Spotted Dolphin........           0.0           0.0  ...............            29.0                 29
Atlantic White-Sided Dolphin....           0.1         199.5              4.6            27.9                200
Bottlenose Dolphin..............           0.0          68.8             51.4             7.8                 69
Common Dolphin..................           0.0       1,327.6          1,308.9            34.9              1,328
Harbor Porpoise.................         320.9         661.0              1.3             2.7                661
Pilot Whales....................           0.0           5.5  ...............             8.4                  9
Risso's Dolphin.................           0.0          15.5              3.6             5.4                 16
Sperm Whale *...................           0.0           2.8  ...............             1.5                  3
Gray Seal.......................           4.9         253.8              3.5             1.4                311
Harbor Seal.....................          32.0         894.8              4.6             1.4                895
----------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.
\1\ Exposure estimates assume all piles will be installed in a single year.

Potential UXO/MEC Detonations

    To assess the impacts from UXO/MEC detonations, JASCO conducted 
acoustic modeling based on previous underwater acoustic assessment work 
that was performed jointly between NMFS and the United States Navy. 
JASCO modeled the acoustic ranges generated by UXO/MEC detonations, 
including three sound pressure metrics (peak pressure level, sound 
exposure level, and acoustic impulse) to the thresholds presented 
previously in Tables 9 and 10. Charge weights of 2.3 kgs, 9.1 kgs, 45.5 
kgs, 227 kgs, and 454 kgs, which is the largest charge the Navy 
considers for the purposes of its analyses (see the Description of the 
Specified Activities section), were modeled to determine the ranges to 
mortality, gastrointestinal injury, lung injury, PTS, and TTS 
thresholds. First, the source pressure function used for estimating 
peak pressure level and impulse metrics was calculated with an 
empirical model that approximates the rapid conversion of solid 
explosive to gaseous form in a small bubble under high pressure, 
followed by exponential pressure decay as that bubble expands (Hannay 
and Zykov, 2022). This initial empirical model is only valid close to 
the source (within tens of meters), so alternative formulas were used 
beyond those distances to a point where the sound pressure decay with 
range transitions to the spherical spreading model. The SEL and SPL 
thresholds for injury and behavioral disturbance occur at distances of 
many water depths in the relatively shallow waters of the project 
(Hannay and Zykov, 2022). As a result, the sound field becomes 
increasingly influenced by the contributions of sound energy reflected 
from the sea surface and sea bottom multiples times. To account for 
this, propagation modeling was carried out in decidecade frequency 
bands using JASCO's MONM, as described in the WTG and OSS Foundation 
Installation section above. This model applies a parabolic equation 
approach for frequencies below 4 kHz and a Gaussian beam ray trace 
model at higher frequencies (Hannay and Zykov, 2022). In the Revolution 
Wind project's location, sound speed profiles generally change little 
with depth, so these environments do not have strong seasonal 
dependence. The propagation modeling was performed using an average 
sound speed profile for summer, which is representative of the most 
likely time of year (May through November) UXO/MEC detonation 
activities would occur, if necessary. Please see Appendix B of 
Revolution Wind's application for more technical details about the 
modeling methods, assumptions and environmental parameters used as 
inputs (Hannay and Zykov, 2022).
    The type and net explosive weight of UXO/MECs that may be detonated 
are not known at this time. To capture a range of potential UXO/MECs, 
five categories or ``bins'' of net explosive weight established by the 
U.S. Navy (2017a) were selected for acoustic modeling (Table 17). These 
charge weights were modeled at four different locations off Rhode 
Island, consisting of different depths (12 m (Site S1), 20 m (Site S2), 
30 m (Site S3), and 45 m (Site S4)). The sites were deemed to be 
representative of both the export cable route and the lease area. Two 
are located along the RWEC corridor (Sites S1 and S2) and two are 
located inside the RWF (Sites S3 and S4). The locations for these 
modeling sites are shown in Figure 1 of Appendix B in Revolution Wind's 
application.
     Shallow water export cable route (ECR): Site S1; In the 
channel within Narragansett Bay (12 m depth);
     Shallow water ECR: Site S2; Intermediate waters outside of 
Narragansett Bay (20 m depth);
     Shallow water lease area: Site S3; Shallower waters in the 
southern portion of the Hazard Zone 2 area (30 m depth);
     Deeper water lease area: Site S4; Deeper waters in 
northern portion of the Hazard Zone 2 area (45 m depth).

            Table 17--Navy ``Bins'' and Corresponding Maximum Charge Weights (Equivalent TNT) Modeled
----------------------------------------------------------------------------------------------------------------
                                                                                     Maximum
                              Navy bin designation                                 equivalent      Weight (TNT)
                                                                                      (kg)             lbs
----------------------------------------------------------------------------------------------------------------
E4.............................................................................             2.3                5

[[Page 79120]]

 
E6.............................................................................             9.1               20
E8.............................................................................            45.5              100
E10............................................................................             227              500
E12............................................................................             454             1000
----------------------------------------------------------------------------------------------------------------

    Below, in Table 18, we present distances to PTS and TTS thresholds 
for only the 454 kg UXO/MEC, as this has the greatest potential for 
these impacts and is what is used to estimate take. NMFS notes that it 
is extremely unlikely that all UXO/MECs for which Revolution Wind deems 
detonation necessary would consist of this 454 kg charge weight. 
However, it is not currently known how easily Revolution Wind would be 
able to identify the size and charge weights of UXOs/MECs in the field. 
Therefore, for this action, NMFS has proposed to require Revolution 
Wind to implement mitigation measures assuming the largest E12 charge 
weight as a conservative approach. We do note that if Revolution Wind 
is able to reliably demonstrate that they can easily and accurately 
identify charge weights in the field, NMFS will consider mitigation and 
monitoring zones based on UXO/MEC charge weight for the final 
rulemaking rather than assuming the largest charge weight in every 
situation.
    To further reduce impacts to marine mammals, Revolution Wind would 
additionally deploy a noise abatement system during detonation events, 
similar to that described for monopile installation, and expects that 
this system would be able to achieve 10-dB attenuation. This 
expectation is based on an assessment of UXO/MEC clearance activities 
in European waters, as summarized by Bellman and Betke (2021).
    Due to the implementation of mitigation and monitoring measures, 
the potential for mortality and non-auditory injury is low and 
Revolution Wind did not request, and we are not proposing to authorize, 
take by mortality or non-auditory injury. For this reason we are not 
presenting all modeling results here; however, they can be found in 
Appendix B of the ITA application.
    For the RWEC, the largest distances to the PTS (Table 18) and TTS 
(Table 20) SEL thresholds were selected among the modeling results for 
Sites S1 and S2. The distances were not always consistently larger for 
one site versus the other, so the results in Tables 18 and 20 represent 
a mixture of the two sites. This same approach was used to determine 
the largest distances to these thresholds for the lease area (Tables 19 
and 21). For all species, the distance to the SEL thresholds exceeded 
that for the peak thresholds (Table 29 in Appendix B of the ITA 
application). Model results for all sites and all charge weights can be 
found in Appendix B of Revolution Wind's application. Further, 
Revolution Wind presented the results for both mitigated and 
unmitigated scenarios in the ITA application and the August 2022 
Updated Densities and Takes Estimation Memo. Since that time, 
Revolution Wind has committed to the use of a noise abatement system 
during all detonations, and plans to achieve a 10-dB noise reduction as 
minimum. As a result, the Updated Densities and Take Estimation Memo 
mitigated UXO/MEC scenario is the one carried forward here. Therefore, 
only the attenuated results are presented in Tables 18-21 and were 
carried forward into the exposure and take estimation. Additional 
information can be found in JASCO's UXO/MEC report and the Revised 
Density and Take Estimate Memo on NMFS' website (https://www.fisheries.noaa.gov/action/incidental-take-authorization-revolution-wind-llc-construction-revolution-wind-energy).
    NMFS notes that the more detailed results for the mortality and 
non-auditory injury analysis for marine mammals for onset 
gastrointestinal injury, onset lung injury, and onset of mortality can 
be found in Appendix B of the ITA application, which can be found on 
NMFS' website. NMFS preliminarily concurs with Revolution Wind's 
analysis and does not expect or propose to authorize any non-auditory 
injury, serious injury, or mortality of marine mammals from UXO/MEC 
detonation. The modeled distances to the mortality threshold for all 
UXO/MECs sizes for all animal masses are small (i.e., 5-353 m; see 
Tables 35-38 in Appendix B of Revolution Wind's application), as 
compared to the distance/area that can be effectively monitored. The 
modeled distances to non-auditory injury thresholds range from 5 to 648 
m (see Tables 30-34 in Appendix B of the application). Revolution Wind 
would be required to conduct extensive monitoring using both PSOs and 
PAM operators and clear an area of marine mammals prior to detonating 
any UXO. Given that Revolution Wind would be employing multiple 
platforms to visually monitor marine mammals as well as passive 
acoustic monitoring, it is reasonable to assume that marine mammals 
would be reliably detected within approximately 660 m of the UXO/MEC 
being detonated such that the potential for mortality or non-auditory 
injury is considered de minimis.
    To estimate the maximum ensonified zones that could result from 
UXO/MEC detonations, the largest E12 R95% to PTS 
and TTS threshold isopleths within the RWEC, Tables 18 and 20, 
respectively, were used as radii to calculate the area of a circle (pi 
x r\2\ where r is the range to the threshold level) for each marine 
mammal hearing group. The results represent the largest area 
potentially ensonified above threshold levels from a single detonation 
within the RWEC corridor. The same method was used to calculate the 
maximum ensonified area from a single detonation in the lease area, 
based on the distances in Tables 19 and 21. Again, modeling results are 
presented here for mitigated (i.e., using a noise abatement system) 
detonations of UXO/MECs (Tables 18-21). The results for unmitigated 
detonations can be found in Tables 44-48 in the ITA application. As 
noted previously, Revolution Wind has committed to the mitigated 
scenario; therefore, for take estimation, Revolution Wind assumes that 
a minimum of 10-dB of noise produced by a detonation would be 
attenuated using a noise abatement system. Thus, the mitigated maximum 
ensonified area for each hearing group for the largest UXO/MEC class 
was used for take estimation.

[[Page 79121]]



Table 18--Largest SEL-Based R95% PTS-Onset Ranges (in Meters) From Sites S1 and S2 (RWEC) Modeled During UXO/MEC
                                     Detonation, Assuming 10-dB Attenuation
----------------------------------------------------------------------------------------------------------------
                                                                   Distance (m) to PTS threshold
                                                                       during E12  (454 kg)           Maximum
                   Marine mammal hearing group                              detonation              ensonified
                                                                 --------------------------------  zone  (km\2\)
                                                                       Rmax            R95%
----------------------------------------------------------------------------------------------------------------
Low-frequency cetaceans.........................................           4,270           3,780            44.9
Mid-frequency cetaceans.........................................             535             461            0.67
High-frequency cetaceans........................................           6,960           6,200             121
Phocid pinnipeds (in water).....................................           1,830           1,600            8.04
----------------------------------------------------------------------------------------------------------------


 Table 19--Largest SEL-Based R95% PTS-Onset Ranges (in Meters) Sites S3 and S4 (Lease Area) Modeled During UXO/
                                   MEC Detonation, Assuming 10-dB Attenuation
----------------------------------------------------------------------------------------------------------------
                                                                   Distance (m) to PTS threshold
                                                                       during E12  (454 kg)           Maximum
                   Marine mammal hearing group                              detonation              ensonified
                                                                 --------------------------------  zone  (km\2\)
                                                                       Rmax            R95%
----------------------------------------------------------------------------------------------------------------
Low-frequency cetaceans.........................................           3,900           3,610            40.9
Mid-frequency cetaceans.........................................             484             412            0.53
High-frequency cetaceans........................................           6,840           6,190            12.0
Phocid pinnipeds (in water).....................................           1,600           1,480            6.88
----------------------------------------------------------------------------------------------------------------


Table 20--Largest SEL-Based R95% TTS-Onset Ranges (in Meters) From Sites S1 and S2 (RWEC) Modeled During UXO/MEC
                                     Detonation, Assuming 10-dB Attenuation
----------------------------------------------------------------------------------------------------------------
                                                                   Distance (m) to TTS threshold
                                                                       during E12  (454 kg)           Maximum
                   Marine mammal hearing group                              detonation              ensonified
                                                                 --------------------------------  zone  (km\2\)
                                                                       Rmax            R95%
----------------------------------------------------------------------------------------------------------------
Low-frequency cetaceans.........................................          13,200          11,900             445
Mid-frequency cetaceans.........................................           2,820           2,550            4.40
High-frequency cetaceans........................................          15,400          14,100             624
Phocid pinnipeds (in water).....................................           7,610           6,990             153
----------------------------------------------------------------------------------------------------------------


 Table 21--Largest SEL-Based R95% TTS-Onset Ranges (in Meters) From Sites S3 and S4 (Lease Area) Modeled During
                                 UXO/MEC Detonation, Assuming 10-dB Attenuation
----------------------------------------------------------------------------------------------------------------
                                                                   Distance (m) to TTS threshold
                                                                       during E12  (454 kg)           Maximum
                   Marine mammal hearing group                              detonation              ensonified
                                                                 --------------------------------  zone  (km\2\)
                                                                       Rmax            R95%
----------------------------------------------------------------------------------------------------------------
Low-frequency cetaceans.........................................          13,500          11,800             437
Mid-frequency cetaceans.........................................           2,730           2,480            19.3
High-frequency cetaceans........................................          15,600          13,700             589
Phocid pinnipeds (in water).....................................           7,820           7,020             155
----------------------------------------------------------------------------------------------------------------

    Regarding the marine mammal density and occurrence data used in the 
take estimates for UXO/MECs, to avoid any in situ detonations of UXO/
MECs during periods when North Atlantic right whale densities are 
highest in and near the RWEC corridor and lease area, Revolution Wind 
has opted for a temporal restriction to not detonate in Federal waters 
from December 1 through April 30 annually. Accordingly, for each 
species, they selected the highest average monthly marine mammal 
density between May and November (Roberts and Halpin (2022)) to 
conservatively estimate exposures from UXO/MEC detonation for a given 
species in any given year (i.e., assumed all 13 UXO/MECs would be 
detonated in the month with the greatest average density). This 
approach is similar to what was used for determining the most 
appropriate species densities for monopile foundation installation. 
Furthermore, given that UXOs/MECs detonations have the potential to 
occur anywhere within the project area, a 15 km (9.32 mi) perimeter was 
applied around the lease area (reduced from the 50 km (31 mi) perimeter 
in the ITA application) and a 10 km (6.2 mi) perimeter was applied to 
the RWEC corridor (see Figures 12 and 13 of the Updated Density and 
Take Estimation Memo). In some cases where monthly densities were 
unavailable, annual densities were used instead for certain species 
(i.e., blue whales, pilot whale spp.).
    Table 22 provides those densities and the associated months in 
which the species-specific densities are highest for

[[Page 79122]]

the RWEC corridor and lease area, respectively.

    Table 22--Maximum of Average Monthly Marine Mammal Densities (Individuals/km\2\) Within 15 Km of the RWEC
                          Corridor and Lease Area (May-November), and Associated Month
----------------------------------------------------------------------------------------------------------------
                                                   RWEC                                 Lease area
                                --------------------------------------------------------------------------------
            Species                  Maximum                                  Maximum
                                     density      Maximum  density month      density     Maximum  density month
----------------------------------------------------------------------------------------------------------------
Blue whale *...................          0.0000  Annual.................          0.0000  Annual.
Fin whale *....................          0.0015  July...................          0.0029  July.
Humpback whale.................          0.0014  May....................          0.0020  May.
Minke whale....................          0.0110  May....................          0.0167  May.
North Atlantic right whale *...          0.0009  May....................          0.0019  May.
Sei whale *....................          0.0007  May....................          0.0012  May.
Atlantic spotted dolphin.......          0.0002  October................          0.0007  October.
Atlantic white-sided dolphin...          0.0086  May....................          0.0175  May.
Bottlenose dolphin.............          0.0047  July...................          0.0093  August.
Common dolphin.................          0.0389  November...............          0.0762  September.
Harbor porpoise................          0.0218  May....................          0.0392  May.
Pilot whales...................          0.0001  Annual.................          0.0007  Annual.
Risso's dolphin................          0.0003  November...............          0.0006  November.
Sperm whale *..................          0.0002  August.................          0.0004  August.
Grey Seal......................          0.0769  May....................          0.0692  May.
Harbor Seal....................          0.1728  May....................          0.1554  May.
----------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.

    To estimate take incidental to UXO/MEC detonations in the RWEC 
corridor, the maximum ensonified areas based on the largest 
R95% to Level A harassment (PTS) and Level B 
harassment (TTS) thresholds (assuming 10-dB attenuation) from a single 
detonation in the RWEC corridor, shown in Tables 18 and 20, were 
multiplied by six (the estimated number of UXOs/MECs that may be 
encountered in the RWEC corridor) and then multiplied by the marine 
mammal densities shown in Table 22, resulting in the take estimates in 
Table 23. For the lease area, the same method was applied, using the 
maximum ensonified areas in Tables 19 and 21 multiplied by seven (the 
estimated number of UXOs/MECs that may be encountered in the lease 
area) and then multiplied by the marine mammal densities shown in Table 
22, resulting in the values shown in the columns for the lease area 
(with the heading ``LA'') of Table 23. Again, Revolution Wind based the 
amount of requested take on the number of exposures estimated assuming 
10-dB attenuation using a noise abatement system because they believe 
consistent, successful implementation of this mitigation measure would 
be possible.
    Revolution Wind has proposed mitigation and monitoring measures 
intended to avoid Level A take of most species, and the extent and 
severity of Level B harassment (see Proposed Mitigation and Proposed 
Monitoring and Reporting sections below). However, given the relatively 
large distances to the high-frequency cetacean Level A harassment (PTS, 
SELcum) isopleth applicable to harbor porpoises, and the 
difficulty detecting this species at sea, Revolution Wind is requesting 
take by Level A harassment of 49 harbor porpoises. Similarly, seals are 
difficult to detect at longer ranges and, although the distance to the 
phocid hearing group SEL PTS threshold is not as large as that for 
high-frequency cetaceans, it may not be possible to detect all seals 
within the threshold distances even with the proposed monitoring 
measures. Therefore, in addition to the requested Level B harassment in 
Table 23, Revolution Wind requested Level A harassment of three gray 
seals and five harbor seals. However, NMFS has adjusted the amount of 
take proposed for authorization to seven gray seals and 16 harbor seals 
to correct for Revolution Wind's arithmetic error in the application 
and Updated Density and Take Estimation memo when summing the density-
based Level A exposures for the lease area and export cable route for 
each species.

     Table 23--Total (5-Year) and Maximum Annual Amount of Level A Harassment (PTS) and Level B Harassment Proposed To Be Authorized From 13 UXO/MEC Detonations Assuming 10-dB Attenuation
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Level A Take                        Level B Take                                            Maximum    Maximum      5-year
                                                                --------------------  Total Level A  ------------------  Total Level B     PSO Data     Mean     annual     annual      total
                            Species                                                   density-based                      density-based       take       group   Level A    Level B    (Level A +
                                                                  LA \1\   ECR \2\    take estimate      LA      ECR     take estimate     estimate     size      take       take      Level B)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Mysticetes:
    Blue Whale *...............................................      0.0        0.0              0.0      0.0      0.0              0.1  ............     1.0          0          1            1
    Fin Whale *................................................      0.8        0.4              1.2      8.9      7.8             16.7           2.5     1.8          0         17           17
    Humpback Whale.............................................      0.6        0.4              0.9      6.1      5.3             11.4           7.6     2.0          0         12           12
    Minke Whale................................................      4.8        3.0              7.7     51.1     44.6             95.7           0.9     1.2          0         96           96
    North Atlantic Right Whale *...............................      0.6        0.2              0.8      6.0      5.2             11.2           0.2     2.4          0         12           12
    Sei Whale *................................................      0.4        0.2              0.5      3.8      3.3              7.0           0.1     1.6          0          8            8
Odontocetes:
    Atlantic Spotted Dolphin...................................      0.0        0.0              0.0      0.1      0.1              0.2  ............    29.0          0         29           29
    Atlantic White-Sided Dolphin...............................      0.1        0.0              0.1      2.4      2.1              4.5           0.7    27.9          0         28           28

[[Page 79123]]

 
    Bottlenose Dolphin.........................................      0.0        0.0              0.1      1.3      1.1              2.4           8.3     7.8          0          9            9
    Common Dolphin.............................................      0.3        0.2              0.4     10.3      9.3             19.6         210.1    34.9          0        211          211
    Harbor Porpoise............................................     33.1       15.8             48.9    161.9    147.0            308.9           0.2     2.7         49        309          358
    Pilot Whales...............................................      0.0        0.0              0.0      0.1      0.1              0.2  ............     8.4          0          9            9
    Risso's Dolphin............................................      0.0        0.0              0.0      0.1      0.1              0.2           0.6     5.4          0          6            6
    Sperm Whale *..............................................      0.0        0.0              0.0      0.1      0.0              0.1  ............     1.5          0          2            2
Pinnipeds:
    Gray Seal..................................................      3.3        3.7                7     75.0     63.7            138.7           0.6     0.4          7        139          146
    Harbor Seal................................................      7.5        8.3             15.8    168.5    143.2            311.6           0.7     1.0         16        312          328
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.
\1\ LA = Lease Area.
\2\ ECR = Export Cable Route.

Temporary Cofferdam Installation and Removal

    Acoustic modeling, using JASCO's MONM-BELLHOP model (used for 
modeling impact pile driving), was performed for [Oslash]rsted's 
Sunrise Wind Farm project to determine distances to the Level A 
harassment and Level B harassment isopleths resulting from installation 
of steel sheet piles to construct cofferdams and installation of casing 
pipes using pneumatic hammering (Kusel et al., 2022b). Revolution Wind 
would install the same type of sheet piles and casing pipe in a similar 
location using the exact same methods as Sunrise Wind used to inform a 
published analysis, therefore the modeling results described for 
Sunrise Wind (Kusel et al., 2022b) and presented here are considered 
applicable to Revolution Wind's project. For take assessment purposes, 
the sheet pile cofferdam scenario results in a larger amount of take by 
Level B harassment and is, therefore, analyzed further in the Estimated 
Take section. This is because acoustic propagation modeling predicts 
that the distance to the Level B harassment threshold isopleth produced 
by vibratory pile driving is approximately 10 km, while the distance to 
the same isopleth produced by pneumatic hammering is approximately 0.92 
km. The sheet pile cofferdam scenario would require up to 56 days of 
vibratory hammer use for installation and removal, while the casing 
pipe scenario would require up to 12 days of vibratory pile driving 
(plus 8 days of pneumatic hammering). The larger number of total days 
of pile driving for the sheet pile cofferdam scenario coupled with the 
fact that vibratory pile driving on all of those days would produce the 
larger Level B harassment zone means the anticipated take, by Level B 
harassment, from the sheet pile cofferdam scenario would necessarily be 
higher and is, therefore, carried forward as the more conservative 
Level B harassment assumption. The acoustic ranges to the Level A 
harassment (SELcum) thresholds from impact pile driving 
(pneumatic hammering) of the casing pipe are estimated to be the 
following for each hearing group: low frequency = 3.87 km, mid 
frequency = 0.23 km, high frequency = 3.95 km, and phocid pinnipeds = 
1.29 km. Level A harassment (SPLpk) thresholds are not 
expected to be generated by pneumatic hammering. The estimated 
distances to Level A harassment SELcum thresholds are larger 
than the distance to the Level B harassment threshold (920 m). This is 
due to the high strike rate of the pneumatic hammer resulting in a high 
number of accumulated strikes per day. However, cetaceans are not 
expected to occur frequently close to this nearshore site, and 
individuals of any species (including seals) are not expected to remain 
within the estimated SELcum threshold distances for the 
entire 3-hour duration of hammering in a day. Given that work would 
occur within Narragansett Bay, the short duration of pneumatic 
hammering, and the implementation of mitigation and monitoring measures 
(including shutdown zones equivalent to the size of the Level A 
harassment zones), Level A harassment incidental to casing pipe 
installation is not expected or proposed for authorization. In 
addition, given the nature of vibratory pile driving and the small 
distances to Level A harassment thresholds (5-190 m), sheet pile 
cofferdam installation is also not expected to result in Level A 
harassment. Revolution Wind did not request, nor is NMFS proposing to 
authorize, any Level A harassment incidental to installation of sheet 
pile cofferdams or the casing pipe scenario.
    In summary, the Level B harassment zone produced by vibratory pile 
driving (9.74 km) is significantly larger than that produced by 
pneumatic hammering (0.92 km). Additionally, as mentioned previously, 
the sheet pile cofferdam scenario would require up to a total of 56 
days of vibratory pile driving for installation and removal, while the 
casing pipe scenario would require up to 24 days of vibratory pile 
driving plus 8 days of pneumatic hammering. The larger spatial impact 
combined with the longer duration of sheet pile cofferdam installation 
would produce a larger amount of Level B harassment; therefore, this 
landfall construction activity was carried forward as the most 
conservative scenario.
    JASCO used its MONM-BELLHOP to predict acoustic propagation for 
frequencies between 5 Hz and 25 kHz produced by vibratory pile driven 
installation of the steel sheet piles that would be used to construct 
temporary cofferdams (Kusel et al., 2022b). Acoustic propagation 
modeling was based on a winter sound speed profile, which was deemed 
both conservative and appropriate for the Revolution Wind project 
because use of the profile generates larger distances to Level A 
harassment and Level B harassment isopleths (versus those generated 
using a summer sound speed profile). Additional modeling assumptions 
are included in Table 24.
    Decidecade band SEL levels were obtained from vibratory pile 
driving measurements available in the literature (Illingworth and 
Rodkin, 2017). The Illingworth and Rodkin (2017) measurements are for 
vibratory driving of four 12-in wide connected sheet piles (48 inch/122 
cm total width) using an APE Model 300 vibratory hammer

[[Page 79124]]

(1842.0 kN centrifugal force). Illingworth and Rodkin (2017) included 
SEL at 10 m from the pile in the frequency band 5-25,000 Hz. The 
average (from 10 piling measurements) maximum broadband SEL was 182.7 
dB re 1 [micro]Pa\2\[middot]s. For modeling of vibratory driving of 
sheet piles at the HDD location, SEL band levels were corrected for 
spherical spreading (+20 dB, corresponding to 10 m range) (Kusel et 
al., 2021).
    Additional details on the acoustic modeling conducted for the 
Sunrise Wind project can be found in the Sunrise Wind Farm Project 
Underwater Noise and Exposure Modeling report available on NMFS' 
website at https://www.fisheries.noaa.gov/action/incidental-take-authorization-sunrise-wind-llc-construction-and-operation-sunrise-wind.

     Table 24--Sheet Pile Installation Acoustic Modeling Assumptions
------------------------------------------------------------------------
               Parameter                           Model input
------------------------------------------------------------------------
Vibratory Hammer......................  APE 300.
Pile Type.............................  Sheet Pile.
Pile Length...........................  30 m.
Pile Width............................  0.6 m.
Pile Wall Thickness...................  2.54 cm.
Seabed Penetration....................  10 m.
Time to Install 1 Pile................  2 hrs.
Number of Piles per Day...............  4.
------------------------------------------------------------------------

    Similar to the modeling approach for impact pile driving, distances 
to harassment thresholds are reported as R95% 
values (Table 25). Distances to the Level A harassment threshold are 
relatively small, ranging from 5 m for low-frequency cetaceans to 190 m 
for high-frequency cetaceans. The distance to the Level B harassment 
threshold is 9,740 m for all species.

  Table 25--Acoustic Ranges (R95%) in Meters to Level A Harassment (PTS) and Level B Harassment Thresholds From
                          Vibratory Pile Driving, Assuming a Winter Sound Speed Profile
----------------------------------------------------------------------------------------------------------------
                                                    R95%  (m)
-----------------------------------------------------------------------------------------------------------------
                                                                      Level A harassment     Level B harassment
                                                                    SELcum thresholds  (dB    SPLrms threshold
                    Marine mammal hearing group                              re 1               (120 dB re 1
                                                                    [micro]Pa\2\[middot]s)       [micro]Pa)
----------------------------------------------------------------------------------------------------------------
Low-frequency.....................................................                      5                  9,740
Mid-frequency.....................................................  ......................                 9,740
High-frequency....................................................                    190                  9,740
Phocid pinniped...................................................                     10                  9,740
----------------------------------------------------------------------------------------------------------------

    Accounting for the effects that nearby land would have on sound 
propagation using a geographic information system (GIS) (ESRI, 2017) 
results in a reduction in the estimated area of 54.1 km\2\ (20.9 mi\2\) 
potentially being ensonified above the 120 dB threshold. As a 
cautionary approach, this 54.1 km\2\ (20.9 mi\2\) includes some areas 
beyond 9.74 km (6.05 mi) from the landfall location and reflects the 
maximum area potentially ensonified above threshold levels from 
construction activities at that site, including if a larger vibratory 
pile driving hammer were to be used.
    Regarding how density and occurrence information was applied in 
estimating take for these activities, the export cable landfall 
construction work would take place near Quonset Point in North 
Kingstown, Rhode Island, which is within Narragansett Bay. However, the 
habitat-based marine mammal densities from Roberts and Halpin (2022) do 
not include waters within Narragansett Bay. As an alternative, 
densities calculated from the area immediately outside of Narragansett 
Bay were used in exposure estimation. This is a conservative approach 
since there have been few reported sightings of marine mammals, other 
than seals, within Narragansett Bay (Raposa, 2009).
    To select marine mammal density grid cells from the Roberts and 
Halpin (2022) data representative of the area just outside of 
Narragansett Bay, a zone representing the ensonified area plus a 5-km 
buffer from the mouth of Narragansett Bay was created in GIS (ESRI, 
2017). This buffer was then intersected with the density grid cells for 
each individual species to select those near the mouth of Narragansett 
Bay (Figure 8 in Revolution Wind's Updated Density and Take Estimation 
Memo). Since the timing of landfall construction could vary somewhat 
from the proposed schedule, the maximum average monthly density from 
January through December for each species was selected (Table 26) and 
used to estimate exposures from landfall construction.

[[Page 79125]]



   Table 26--Maximum Average Monthly Marine Mammal Densities in and Near the Mouth of Narragansett Bay and the
                                   Month in Which Each Maximum Density Occurs
----------------------------------------------------------------------------------------------------------------
                                                   Maximum monthly
                    Species                        density  (Ind/               Maximum density month
                                                       km\2\)
----------------------------------------------------------------------------------------------------------------
                                                   Mysticetes
----------------------------------------------------------------------------------------------------------------
Blue Whale *...................................              0.0000  Annual.
Fin Whale *....................................              0.0000  ...........................................
Humpback Whale.................................              0.0004  December.
Minke Whale....................................              0.0005  May.
North Atlantic Right Whale *...................              0.0002  March.
Sei Whale *....................................              0.0002  April.
----------------------------------------------------------------------------------------------------------------
                                                   Odontocetes
----------------------------------------------------------------------------------------------------------------
Atlantic Spotted Dolphin.......................              0.0000  ...........................................
Atlantic White-Sided Dolphin...................              0.0004  November.
Bottlenose Dolphin.............................              0.0002  September.
Common Dolphin.................................              0.0065  November.
Harbor Porpoise................................              0.0125  December.
Pilot Whales...................................              0.0000  ...........................................
Risso's Dolphin................................              0.0000  ...........................................
Sperm Whale *..................................              0.0000  ...........................................
----------------------------------------------------------------------------------------------------------------
                                                    Pinnipeds
----------------------------------------------------------------------------------------------------------------
Gray seal......................................               0.128  October.
Harbor seal....................................               0.204  October.
----------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.

Cable Landfall Construction Take Estimation
    Given the short duration of the activity and shallow, coastal 
location, animat exposure modeling was not conducted for cofferdam 
installation and removal to determine potential exposures from 
vibratory pile driving. Rather, the modeled acoustic ranges to Level A 
harassment and Level B harassment isopleths were used to calculate the 
area around the cofferdam predicted to be ensonified daily to levels 
that exceed the thresholds, or the Ensonified Area. The Ensonified Area 
was calculated as the following:

Ensonified Area = pi*r\2\,

    Where r is the linear acoustic range from the source to the Level A 
harassment and Level B harassment isopleths.
    To calculate density-based exposures estimates incidental to 
installation of two cofferdams, the average marine mammal densities 
from Table 26 were multiplied by the daily ensonified area (54.1 km\2\) 
for installation of sheet piles. Given that use of the vibratory hammer 
during cofferdam installation and removal may occur on up to 56 days, 
the daily estimated take was multiplied by 56 to produce the results 
shown in Table 27. However, as noted above, to be conservative, 
Revolution Wind has requested take by Level B harassment based on the 
highest exposures predicted among the density-based, PSO-based, or 
average group size-based estimates; the take proposed for authorization 
is indicated in column 5 of Table 27 below. Mysticete whales are 
unlikely to occur in the immediate vicinity of the activity or within 
Narragansett Bay (Raposa, 2009); therefore, Revolution Wind is not 
requesting and NMFS is not proposing to authorize, take of these 
species. Given the small distances to Level A harassment isopleths 
(shown in Table 25), Level A harassment incidental to this activity is 
not anticipated, even absent mitigation. Therefore, Revolution Wind is 
not requesting and NMFS is not proposing to authorize Level A take.

                   Table 27--Estimated Level B Harassment Incidental to Cofferdam Construction
----------------------------------------------------------------------------------------------------------------
                                            Density-based    PSO data  take                      Highest level B
                 Species                    take estimate       estimate       Mean group size        take
----------------------------------------------------------------------------------------------------------------
Odontocetes:
    Atlantic Spotted Dolphin............               0.1  ................              29.0                29
    Atlantic White-Sided Dolphin........               1.2               3.2              27.9                28
    Bottlenose Dolphin..................               0.5              35.5               7.8                36
    Common Dolphin......................              19.6             904.9              34.9               905
    Harbor Porpoise.....................              37.8               0.9               2.7                38
    Pilot Whales........................               0.0  ................               8.4                 9
    Risso's Dolphin.....................               0.1               2.5               5.4                 6
    Sperm Whale *.......................               0.1  ................               1.5                 2
Pinnipeds:
    Gray Seal...........................             353.5               2.5               1.4               354
    Harbor Seal.........................             794.3               3.2               1.4               795
----------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.


[[Page 79126]]

HRG Surveys

    Revolution Wind's proposed HRG survey activity includes the use of 
impulsive (i.e., boomers and sparkers) and non-impulsive (e.g., CHIRP 
SBPs) sources. NMFS has concluded that Level A harassment is not a 
reasonably likely outcome for marine mammals exposed to noise from the 
sources proposed for use here, and the potential for Level A harassment 
is not evaluated further in this document. Please see Revolution Wind's 
application for details of a quantitative exposure analysis (i.e., 
calculated distances to Level A harassment isopleths and Level A 
harassment exposures). Revolution Wind did not request, and NMFS is not 
proposing to authorize, take by Level A harassment incidental to HRG 
surveys.
    For HRG surveys, in order to better consider the narrower and 
directional beams of some of the sources, NMFS has developed a tool for 
determining the 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. Revolution Wind 
used NMFS' 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 
beamwidths, the maximum beam width was used, and the lowest frequency 
of the source (refer back to Table 2) was used when calculating the 
frequency-dependent absorption coefficient.
    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 ranges to the Level A harassment and 
Level B harassment isopleths. 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. Revolution 
Wind utilized the following criteria for selecting the appropriate 
inputs into the NMFS User Spreadsheet Tool (NMFS, 2018):
    (1) For equipment that was measured in Crocker and Fratantonio 
(2016), the reported SL for the most likely operational parameters was 
selected.
    (2) For equipment not measured in Crocker and Fratantonio (2016), 
the best available manufacturer specifications were selected. Use of 
manufacturer specifications represent the absolute maximum output of 
any source and do not adequately represent the operational source. 
Therefore, they should be considered an overestimate of the sound 
propagation range for that equipment.
    (3) For equipment that was not measured in Crocker and Fratantonio 
(2016) and did not have sufficient manufacturer information, the 
closest proxy source measured in Crocker and Fratantonio (2016) was 
used.
    The Dura-spark measurements and specifications provided in Crocker 
and Fratantonio (2016) were used for all sparker systems proposed for 
the HRG surveys. These included variants of the Dura-spark sparker 
system and various configurations of the GeoMarine Geo-Source sparker 
system. 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. 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 joules (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 
source level; therefore, the single maximum source level value was used 
for both operational levels of the S-Boom.
    Table 2 identifies all the representative survey equipment that 
operates below 180 kHz (i.e., at frequencies that are audible and have 
the potential to disturb marine mammals) that may be used in support of 
planned survey activities, and are likely to be detected by marine 
mammals given the source level, frequency, and beamwidth of the 
equipment.
    Results of modeling using the methodology described above indicated 
that, of the HRG equipment planned for use by Revolution Wind that has 
the potential to result in Level B harassment of marine mammals, sound 
produced by the Applied Acoustics sparkers and Applied Acoustics 
triple-plate S-boom would propagate furthest to the Level B harassment 
isopleth (141 m; Table 28). For the purposes of take estimation, it was 
conservatively assumed that sparkers and/or boomers would be the 
dominant acoustic source for all vessel days (although, again, this may 
not always be the case). Thus, the range to the isopleth corresponding 
to the threshold for Level B harassment for and the boomer and sparkers 
(141 m) was used as the basis of take calculations for all marine 
mammals. This is a conservative approach, as the actual sources used on 
individual vessel days, or during a portion of a vessel day, may 
produce smaller distances to the Level B harassment isopleth.

  Table 28--Distances to the Level B Harassment Thresholds for Each HRG Sound Source or Comparable Sound Source
                                  Category for Each Marine Mammal Hearing Group
----------------------------------------------------------------------------------------------------------------
                                                                                                   Level B  (m)
                                                                                                 ---------------
                Equipment type                                Representative model                 All  (SPLrms)
 
----------------------------------------------------------------------------------------------------------------
Sub-bottom Profiler...........................  EdgeTech 216....................................               9
                                                EdgeTech 424....................................               4
                                                Edgetech 512....................................               6
                                                GeoPulse 5430A..................................              21
                                                Teledyn Benthos CHIRP III--TTV 170..............              48
Sparker.......................................  Applied Acoustics Dura-Spark UHD (700 tips,                   34
                                                 1,000 J).
                                                Applied Acoustics Dura-Spark UHD (400 tips, 500              141
                                                 J).
                                                Applied Acoustics Dura-Spark UHD (400 tips, 500              141
                                                 J).
Boomer........................................  Applied Acoustics triple plate S-Boom (700-1,000             141
                                                 J).
----------------------------------------------------------------------------------------------------------------


[[Page 79127]]

    To estimate densities for the HRG surveys occurring both within the 
lease area and within the RWEC based on Roberts and Halpin (2022), a 5-
km (3.11 mi) perimeter was applied around each area (see Figures 10 and 
11 of the Updated Density and Take Estimation Memo). Given this work 
could occur year-round, the annual average density for each species was 
calculated using average monthly densities from January through 
December (Table 29).

Table 29--Annual Average Marine Mammal Densities Along the RWEC Corridor
                             and Lease Area
------------------------------------------------------------------------
                                           RWEC corridor    Lease area
                                          annual average  annual average
                 Species                   density (Ind/   density (Ind/
                                              km\2\)          km\2\)
------------------------------------------------------------------------
Mysticetes:
    Blue Whale *........................          0.0000          0.0000
    Fin Whale *.........................          0.0008          0.0016
    Humpback Whale......................          0.0008          0.0010
    Minke Whale.........................          0.0022          0.0044
    North Atlantic Right Whale *........          0.0011          0.0027
    Sei Whale *.........................          0.0003          0.0004
Odontocetes:
    Atlantic Spotted Dolphin............          0.0000          0.0001
    Atlantic White-Sided Dolphin........          0.0038          0.0090
    Bottlenose Dolphin..................          0.0021          0.0049
    Common Dolphin......................          0.0202          0.0409
    Harbor Porpoise.....................          0.0191          0.0316
    Pilot Whales........................          0.0001          0.0005
    Risso's Dolphin.....................          0.0001          0.0003
    Sperm Whale *.......................          0.0001          0.0001
Pinnipeds:
    Seals (Harbor and Gray).............          0.1477          0.1182
------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.

    The maximum range (i.e., 141 m) to the Level B harassment threshold 
and the estimated trackline distance traveled per day by a given survey 
vessel (i.e., 70 km) were used to calculate the daily ensonified area, 
or zone of influence (ZOI) around the survey vessel.
    The ZOI is a representation of the maximum extent of the ensonified 
area around a HRG sound source over a 24-hr period. The ZOI for each 
piece of equipment operating at or below 180 kHz was calculated per the 
following formula:

ZOI = (Distance/day x 2r) + pi*r\2\

    Where r is the linear distance from the source to the harassment 
isopleth.
    The largest daily ZOI (19.8 km\2\), associated with the proposed 
use of boomers and sparkers, was applied to all planned vessel days.
    Potential Level B density-based harassment exposures are estimated 
by multiplying the average annual density of each species within the 
survey area by the daily ZOI. That product was then multiplied by the 
number of planned vessel days in each sector during the approximately 
1-year construction timeframe (82.1 in RWEC corridor, 165.7 in lease 
area), and the product was rounded to the nearest whole number. These 
results are shown in columns 2 (lease area) and 3 (RWEC corridor) of 
Table 30. Similar to the approach described above, to be conservative, 
Revolution Wind has requested take by Level B harassment based on the 
highest exposures predicted by the density-based, PSO based, or average 
group size-based estimates, and the take proposed for authorization is 
indicated in column 7 of Table 30 below.

    Table 30--Estimated Take, by Level B Harassment, Incidental to HRG Surveys During the Construction Period
                                                    [Year 1]
----------------------------------------------------------------------------------------------------------------
    Construction phase density-based exposures by survey area        Total
-----------------------------------------------------------------   density-     PSO data      Mean     Highest
                                              Lease       RWEC     based take      take       group     Level B
                  Species                      area     corridor    estimate     estimate      size       take
----------------------------------------------------------------------------------------------------------------
Mysticetes:
    Blue Whale *..........................        0.0        0.0          0.0  ...........        1.0          1
    Fin Whale *...........................        4.4        1.4          5.8          6.6        1.8          7
    Humpback Whale........................        2.8        1.2          4.0         16.5        2.0         17
    Minke Whale...........................       11.8        3.7         15.5          5.9        1.2         16
    North Atlantic Right Whale *..........        7.4        1.8          9.2  ...........        2.4         10
    Sei Whale *...........................        1.1        0.4          1.6  ...........        1.6          2
Odontocetes:
    Atlantic Spotted Dolphin..............        0.3        0.1          0.3  ...........       29.0         29
    Atlantic White-Sided Dolphin..........       24.5        6.5         31.0  ...........       27.9         31
    Bottlenose Dolphin....................       13.2        3.8         17.0        100.1        7.8        101
    Common Dolphin........................      110.5       33.5        144.0      2,353.4       34.9      2,354
    Harbor Porpoise.......................       85.4       30.9        116.3  ...........        2.7        117
    Pilot Whales..........................        1.4        0.1          1.5  ...........        8.4          9

[[Page 79128]]

 
    Risso's Dolphin.......................        0.8        0.2          1.0          2.3        5.4          6
    Sperm Whale *.........................        0.4        0.1          0.5  ...........        1.5          2
Pinnipeds:
    Gray Seal.............................       98.5       75.5        174.0          7.1        1.4        174
    Harbor Seal...........................      221.2      169.6        390.9         11.2        1.4        391
----------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.

    Authorized takes would be by Level B harassment only, in the form 
of disruption of behavioral patterns for individual marine mammals 
resulting from exposure to noise from certain HRG acoustic sources. 
Based primarily on the characteristics of the signals produced by the 
acoustic sources planned for use, Level A harassment is neither 
anticipated (even absent mitigation), nor proposed to be authorized. 
Consideration of the anticipated effectiveness of the mitigation 
measures (i.e., pre-start clearance and shutdown measures), discussed 
in detail below in the Proposed Mitigation section, further strengthens 
the conclusion that Level A harassment is not a reasonably expected 
outcome of the survey activity. No serious injury or mortality is 
anticipated or proposed to be authorized for this activity.
    As mentioned previously, HRG surveys would also routinely be 
carried out during the period of time following construction of the RWF 
and RWEC corridor which, for the purposes of exposure modeling, 
Revolution Wind assumed to be four years. Revolution Wind estimates 
that HRG surveys would cover 2,117 km within the lease area and 1,642 
km along the RWEC corridor annually. Assuming 70 km are surveyed per 
day, this amounts to 30.2 days of survey activity in the lease area and 
23.5 days of survey activity along the RWEC each year, or 214.8 days 
total for the 4-year timeframe following the construction period 
(assuming all construction activities occur in a single year). Density-
based take was estimated using the same approach outlined above by 
multiplying the daily ZOI by the annual average densities and 
separately by the number of vessel days planned for the RWEC and lease 
area; the results are shown in columns 2 and 3, respectively, in Table 
31. Using the same approach described above, Revolution Wind estimated 
a conservative amount of annual take, by Level B harassment, based on 
the highest exposures predicted by the density-based, PSO-based, or 
average group size-based estimates. The highest predicted exposure 
value was multiplied by four to yield the amount of take Revolution 
Wind requested and that is proposed for authorization, shown in column 
8 of Table 31 below.

            Table 31--Estimated Take, by Level B Harassment, From HRG Surveys During Non-Construction Years (Years 2-5) and Total 4-Year Take
--------------------------------------------------------------------------------------------------------------------------------------------------------
          Annual operations phase density-based exposures by survey area                                                            Highest
-----------------------------------------------------------------------------------   Annual total     Annual  PSO       Mean       annual       4-Year
                                                                                     density-based      data  take      group       Level B     Level B
                           Species                              Lease       RWEC       exposures         estimate        size    take  (years     take
                                                                 area     corridor                                                   2-5)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mysticetes:
    Blue Whale *............................................        0.0        0.0              0.0  ...............        1.0             1          4
    Fin Whale *.............................................        1.0        0.4              1.3              1.6        1.8             2          8
    Humpback Whale..........................................        0.6        0.4              1.0              4.0        2.0             5         20
    Minke Whale.............................................        2.6        1.0              3.6              1.5        1.2             4         16
    North Atlantic Right Whale *............................        1.6        0.5              2.1  ...............        2.4             3         12
    Sei Whale *.............................................        0.3        0.1              0.4  ...............        1.6             2          8
Odontocetes:
    Atlantic Spotted Dolphin................................        0.1        0.0              0.1  ...............       29.0            29        116
    Atlantic White-Sided Dolphin............................        5.4        1.8              7.2  ...............       27.9            28        112
    Bottlenose Dolphin......................................        2.9        1.0              3.9             24.6        7.8            25        100
    Common Dolphin..........................................       24.5        9.4             33.8            578.0       34.9           579      2,316
    Harbor Porpoise.........................................       18.9        8.9             27.8  ...............        2.7            28        112
    Pilot Whales............................................        0.3        0.0              0.3  ...............        8.4             9         36
    Risso's Dolphin.........................................        0.2        0.1              0.2              0.6        5.4             6         24
    Sperm Whale *...........................................        0.1        0.0              0.1  ...............        1.5             2          8
Pinnipeds:
    Gray Seal...............................................       27.2       21.1             48.3              1.7        1.4            49        196
    Harbor Seal.............................................       61.1       47.5            108.6              2.7        1.4           109        436
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.


[[Page 79129]]

Total Proposed Take Across All Activities

    Level A harassment and Level B harassment proposed take numbers for 
the combined activities of impact pile driving (assuming 10-dB of sound 
attenuation) during the installation of monopiles; vibratory pile 
driving for cofferdam installation and removal; HRG surveys; and 
potential UXO/MEC detonation(s) (assuming 10-dB attenuation) are 
provided by year in Table 32. The mitigation and monitoring measures 
provided in the Proposed Mitigation and Proposed Monitoring and 
Reporting sections are activity-specific and are designed to minimize 
acoustic exposures to marine mammal species.
    The take numbers NMFS proposes for authorization (Table 32) are 
considered conservative for the following key reasons:
     Proposed take numbers assume installation of three piles 
per day to estimate the potential for Level A harassment, and assumed 
all foundation piles (n=81) would be installed in the month with the 
highest average annual density for each marine mammal species;
     Proposed take numbers for vibratory pile driving assume 
that two sheet pile temporary cofferdams will be 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 the highest average monthly densities across the proposed 
construction months; and,
     Proposed Level A harassment take numbers do not fully 
account for the likelihood that marine mammals would avoid a stimulus 
when possible before the individual accumulates enough acoustic energy 
to potentially cause auditory injury, or the effectiveness of the 
proposed monitoring and mitigation measures (with the exception of 
North Atlantic right whales, given the extensive mitigation measures 
proposed for this species).
    The Year 1 take estimates include 218.7 days of HRG surveys, impact 
installation of WTG and OSS foundations, cofferdam installation/
removal, and mitigated UXO/MEC detonations. Year 2 includes 53.7 days 
of HRG surveys, and potential impact installation of WTG and OSS 
monopile foundations, depending on whether or not delays in the 
schedule for Year 1 occur. Years 3, 4, and 5 each include 53.7 days of 
HRG surveys. Although temporary cofferdam installation/removal could 
occur in Year 2, all of the proposed takes were allocated to Year 1 as 
this represents the most accurate construction scenario. All impact 
pile driving activities for the WTGs and OSSs could also occur outside 
of Year 1; however, all of the takes were allocated to Year 1 as this 
represents the most likely scenario.

Table 32--Estimated Level A Harassment and Level B Harassment Takes for All Activities Proposed To Be Conducted During the Revolution Wind Offshore Wind
                                                                 Energy Facility Project
                                                                       [2023-2028]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                   Year 1            Year 2            Year 3            Year 4            Year 5         5-Year total
                                     NMFS         (maximum)    -----------------------------------------------------------------------------------------
             Species                 stock   ------------------
                                   abundance  Level A  Level B  Level A  Level B  Level A  Level B  Level A  Level B  Level A  Level B  Level A  Level B
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mysticetes:
    Blue Whale *................     \1\ 412        0        3        0        1        0        1        0        1        0        1        0        7
    Fin Whale *.................       6,802        0       40        0        2        0        2        0        2        0        2        0       48
    Humpback Whale..............       1,396        7       77        0        5        0        5        0        5        0        5        7       97
    Minke Whale.................      21,968        0      304        0        4        0        4        0        4        0        4        0       32
    North Atlantic Right Whale *         368        0       44        0        3        0        3        0        3        0        3        0       56
    Sei Whale *.................       6,292        0       18        0        2        0        2        0        2        0        2        0       26
Odontocetes:
    Atlantic Spotted Dolphin....      39,921        0       87        0       29        0       29        0       29        0       29        0      203
    Atlantic White-sided Dolphin      93,233        0      260        0       28        0       28        0       28        0       28        0      372
    Bottlenose Dolphin..........      62,851        0      180        0       25        0       25        0       25        0       25        0      280
    Common Dolphin..............     172,974        0    3,913        0      579        0      579        0      579        0      579        0    6,229
    Harbor Porpoise.............      95,543       49    1,125        0       28        0       28        0       28        0       28       49    1,237
    Pilot Whales................      68,139        0       27        0        9        0        9        0        9        0        9        0       63
    Risso's Dolphin.............      35,215        0       28        0        6        0        6        0        6        0        6        0       52
    Sperm Whale *...............       4,349        0        7        0        2        0        2        0        2        0        2        0       15
Pinnipeds:
    Gray Seal...................      27,300        7      978        0       49        0       49        0       49        0       49        7    1,174
    Harbor Seal.................      61,336       16    2,393        0      109        0      109        0      109        0      109       16    2,829
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Listed as Endangered under the Endangered Species Act (ESA).
\1\ The minimum blue whale population is estimated at 412, although the exact value is not known. NMFS is utilizing this value for our preliminary small
  numbers determination, as shown in parenthesis.

    In making the negligible impact determination and the necessary 
small numbers finding, NMFS assesses the greatest number of proposed 
take of marine mammals that could occur within any one year, which in 
the case of this rule is based on the predicted Year 1 for all species. 
In this calculation, the maximum estimated number of Level A harassment 
takes in any one year is summed with the maximum estimated number of 
Level B harassment takes in any one year for each species to yield the 
highest amount of estimated take that could occur in any year. We 
recognize that certain activities could shift within the 5-year 
effective period of the rule; however, the rule allows for that 
flexibility and the takes are not expected to exceed those shown in 
Table 33 in any year.

[[Page 79130]]



 Table 33--Maximum Number of Requested Takes (Level A Harassment and Level B Harassment) That Could Occur in any
                                             One Year of the Project
----------------------------------------------------------------------------------------------------------------
                                                         Maximum annual take proposed for authorization
                                               -----------------------------------------------------------------
                                                                                   Max annual
                                   NMFS  stock                                     take  (max     Total percent
             Species                 abundance   Max  Level A    Max  Level B       Level A        stock taken
                                                  harassment      harassment      harassment +       based on
                                                                                  max Level B    maximum  annual
                                                                                  harassment)        take \1\
----------------------------------------------------------------------------------------------------------------
Mysticetes:
    Blue Whale *.................      \2\ 412               0               3                3             0.73
    Fin Whale *..................        6,802               0              40               40             0.59
    Humpback Whale...............        1,396               7              77               94             6.67
    Minke Whale..................       21,968               0             304              304             1.38
    North Atlantic Right Whale *.          368               0              44               44             12.0
    Sei Whale *..................        6,292               0              18               18             0.29
Odontocetes:
    Atlantic Spotted Dolphin.....       39,921               0              87               87             0.22
    Atlantic White-sided Dolphin.       93,233               0             260              260             0.28
    Bottlenose Dolphin...........       62,851               0             180              180             0.29
    Common Dolphin...............      172,974               0           3,913            3,913             2.26
    Harbor Porpoise..............       95,543              49           1,125            1,125             1.18
    Pilot Whales.................       68,139               0              27               27             0.04
    Risso's Dolphin..............       35,215               0              28               28             0.08
    Sperm Whale *................        4,349               0               7                7             0.16
Pinnipeds:
    Gray Seal....................       27,300               7             978              985             3.60
    Harbor Seal..................       61,336              16           2,393            2,409             3.93
----------------------------------------------------------------------------------------------------------------
* Listed as Endangered under the Endangered Species Act (ESA).
\1\ Calculations of percentage of stock taken are based on the maximum requested Level A harassment take in any
  one year + the total requested Level B harassment take in any one year and then compared against the best
  available abundance estimate as shown in Table 5. For this proposed action, the best available abundance
  estimates are derived from the NMFS Stock Assessment Reports (Hayes et al., 2022).
\2\ The minimum blue whale population is estimated at 412, although the exact value is not known. NMFS is
  utilizing this value for our preliminary small numbers determination, as shown in parenthesis.

Proposed Mitigation

    In order to promulgate a rulemaking under section 101(a)(5)(A) of 
the MMPA, NMFS must set forth the permissible methods of taking 
pursuant to the activity, and other means of effecting the least 
practicable impact on the species or stock and its habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of the species or stock for 
taking for certain subsistence uses (latter not applicable for this 
action). NMFS' regulations require applicants for incidental take 
authorizations to include information about the availability and 
feasibility (economic and technological) of equipment, methods, and 
manner of conducting the activity or other means of effecting the least 
practicable adverse impact upon the affected species or stocks and 
their habitat (50 CFR 216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, we 
carefully consider two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned), the likelihood of effective implementation (probability 
implemented as planned), and;
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.
    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 (e.g., soft-start, establishing shutdown zones). 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, while 
providing estimates of the areas within which Level B harassment might 
occur.
    Generally speaking, the measures considered and proposed here fall 
into three categories: temporal (seasonal and daily) work restrictions, 
real-time measures (shutdown, clearance zones, and vessel strike 
avoidance), and noise abatement/reduction measures. Seasonal work 
restrictions are designed to avoid or minimize operations when marine 
mammals are concentrated or engaged in behaviors that make them more 
susceptible, or make impacts more likely) in order to reduce both the 
number and severity of potential takes, and are effective in reducing 
both chronic (longer-term) and acute effects. Real-time measures, such 
as shutdown and pre-clearance zones, and vessel strike avoidance 
measures, are intended to reduce the probability or scope of near-term 
acute impacts by taking steps in real time once a higher-risk scenario 
is identified (i.e., once animals are detected within an impact zone). 
Noise

[[Page 79131]]

abatement measures, such as bubble curtains, are intended to reduce the 
noise at the source, which reduces both acute impacts, as well as the 
contribution to aggregate and cumulative noise that results in longer 
term chronic impacts.
    Below, we describe training, coordination, and vessel strike 
avoidance measures that apply to all activity types, and then in the 
following subsections we describe the measures that apply specifically 
to WTG and OSS foundation installation, cofferdam or casing pipe 
scenario installation and removal, UXO/MEC detonations, HRG surveys, 
and fishery monitoring surveys.

Training and Coordination

    Revolution Wind would be required to instruct all project personnel 
regarding the authority of the marine mammal monitoring team(s). For 
example, the e.g., HRG acoustic equipment operator, pile driving 
personnel, etc., would be required to immediately comply with any call 
for a delay or shutdown by the Lead PSO. Any disagreement between the 
Lead PSO and the project personnel would only be discussed after delay 
or shutdown has occurred. All relevant personnel and the marine mammal 
monitoring team would be required to participate in joint, onboard 
briefings that would be led by Revolution Wind project personnel and 
the Lead PSO prior to the beginning of project activities. This would 
serve to ensure that all relevant responsibilities, communication 
procedures, marine mammal monitoring and mitigation protocols, 
reporting protocols, safety, operational procedures, and ITA 
requirements are clearly understood by all involved parties. The 
briefing would be repeated whenever new relevant personnel (e.g., new 
PSOs, acoustic source operators, relevant crew) join the operation 
before work commences.
    More information on vessel crew training requirements can be found 
in the Vessel Strike Avoidance Measures section below.
North Atlantic Right Whale Awareness Monitoring
    Revolution Wind must use available sources of information on North 
Atlantic right whale presence, including daily monitoring of the Right 
Whale Sightings Advisory System, monitoring of Coast Guard VHF Channel 
16 throughout each day to receive notifications of any sightings, and 
information associated with any regulatory management actions (e.g., 
establishment of a zone identifying the need to reduce vessel speeds). 
Maintaining daily awareness and coordination affords increased 
protection of North Atlantic right whales by understanding North 
Atlantic right whale presence in the area through ongoing visual and 
passive acoustic monitoring efforts and opportunities (outside of 
Revolution Wind's efforts), and allows for planning of construction 
activities, when practicable, to minimize potential impacts on North 
Atlantic right whales.
Protected Species Observers and PAM Operator Training
    Revolution Wind would employ NMFS-approved PSOs and PAM operators. 
The PSO field team and PAM team would have a lead member (designated as 
the ``Lead PSO'' or ``PAM Lead'') who would have prior experience 
observing mysticetes, odontocetes and pinnipeds in the Northwestern 
Atlantic Ocean on other offshore projects requiring PSOs. Any remaining 
PSOs and PAM operators must have previous experience observing marine 
mammals during projects and must have the ability to work with all 
required and relevant software and equipment. New and/or inexperienced 
PSOs would be paired with an experienced PSO to ensure that the quality 
of marine mammal observations and data recording is kept consistent.
    All PSOs and PAM operators would be required to complete a Permits 
and Environmental Compliance Plan (PECP) training, as well as a two-day 
training and refresher session on monitoring protocols. These trainings 
would be held with the PSO provider and project compliance 
representatives and would occur before the start of project activities 
related to the construction and development of the Revolution Wind 
Offshore Wind Farm Project. PSOs would be required during all 
foundation installations, cofferdam or casing pipe installation/removal 
activities, UXO/MEC detonations, and HRG surveys. More information on 
requirements during each activity can be found in the Proposed 
Monitoring and Reporting section.

Vessel Strike Avoidance Measures

    This proposed rule contains numerous vessel strike avoidance 
measures. Revolution Wind will be required to comply with these 
measures, except under circumstances when doing so would create an 
imminent and serious threat to a person or vessel, or to the extent 
that a vessel is unable to maneuver and, because of the inability to 
maneuver, the vessel cannot comply (e.g., due to towing, etc.). Vessel 
operators and crews will receive protected species identification 
training prior to the start of in-water construction activities. This 
training will cover information about marine mammals and other 
protected species known to occur or which have the potential to occur 
in the project area. It will include training on making observations in 
both good weather conditions (i.e., clear visibility, low wind, and low 
sea state) and bad weather conditions (i.e., fog, high winds and high 
sea states, in glare). Training will not only include identification 
skills, but will also include information and resources available 
regarding applicable Federal laws and regulations for protected 
species.
    Revolution Wind will abide by the following vessel strike avoidance 
measures:
     All 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.
     During any vessel transits within or to/from the 
Revolution Wind project area, such as for crew transfers), an observer 
would be stationed at the best vantage point of the vessel(s) to ensure 
that the vessel(s) are maintaining the appropriate separation distance 
from marine mammals.
     Year-round and when a vessel is in transit, all vessel 
operators will continuously monitor U.S. Coast Guard VHF Channel 16 
over which North Atlantic right whale sightings are broadcasted.
     At the onset of transiting and at least once every four 
hours, vessel operators and/or trained crew members will monitor the 
project's Situational Awareness System, WhaleAlert, and the Right Whale 
Sighting Advisory System (RWSAS) for the presence of North Atlantic 
right whales. Any observations of any large whale by any Revolution 
Wind staff or contractors, including vessel crew, must be communicated 
immediately to PSOs, PAM operator, and all vessel captains to increase 
situational awareness. Conversely, any large whale observation or 
detection via a sighting network (e.g., Mysticetus) by PSOs or PAM 
operators will be conveyed to vessel operators and crew.
     All vessels would comply with existing NMFS regulations 
and speed restrictions and state regulations as applicable for North 
Atlantic right whales.
     In the event that any Slow Zone (designated as a Dynamic 
Management Area (DMA)) is established that overlaps with an area where 
a project-associated

[[Page 79132]]

vessel would operate, that vessel, regardless of size, will transit 
that area at 10 knots or less.
     Between November 1st and April 30th, all vessels, 
regardless of size, would operate port to port (specifically from ports 
in New Jersey, New York, Maryland, Delaware, and Virginia) at 10 knots 
or less, except for vessels while transiting in Narragansett Bay or 
Long Island Sound (which have not been demonstrated by best available 
science to provide consistent habitat for North Atlantic right whales).
     All vessels, regardless of size, would immediately reduce 
speed to 10 knots or less when any large whale, mother/calf pairs, or 
large assemblages of non-delphinid cetaceans are observed near (within 
500 m) an underway vessel.
     All vessels, regardless of size, would immediately reduce 
speed to 10 knots or less when a North Atlantic right whale is sighted, 
at any distance, by an observer or anyone else on the vessel.
     If a vessel is traveling at greater than 10 knots, in 
addition to the required dedicated visual observer, real-time PAM of 
transit corridors must be conducted prior to and during transits. If a 
North Atlantic right whale is detected via visual observation or PAM 
within or approaching the transit corridor, all crew transfer vessels 
must travel at 10 knots or less for the following 12 hours. Each 
subsequent detection will trigger a 12-hour reset. A slowdown in the 
transit corridor expires when there has been no further visual or 
acoustic detection of North Atlantic right whales in the transit 
corridor in the past 12 hours.
     All underway vessels (e.g., transiting, surveying) must 
have a dedicated visual observer on duty at all times to monitor for 
marine mammals within a 180[deg] direction of the forward path of the 
vessel (90[deg] port to 90[deg] starboard). Visual observers must be 
equipped with alternative monitoring technology for periods of low 
visibility (e.g., darkness, rain, fog, etc.). The dedicated visual 
observer must receive prior training on protected species detection and 
identification, vessel strike minimization procedures, how and when to 
communicate with the vessel captain, and reporting requirements in this 
proposed action. Visual observers may be third-party observers (i.e., 
NMFS-approved PSOs) or crew members and must not have any other duties 
other than observing for marine mammals. Observer training related to 
these vessel strike avoidance measures must be conducted for all vessel 
operators and crew prior to the start of in-water construction 
activities to distinguish marine mammals from other phenomena and 
broadly to identify a marine mammal as a North Atlantic right whale, 
other whale (defined in this context as sperm whales or baleen whales 
other than North Atlantic right whales), or other marine mammal. 
Confirmation of the observers' training and understanding of the ITA 
requirements must be documented on a training course log sheet and 
reported to NMFS.
     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 North Atlantic right 
whale, the vessel operator must assume that it is a North Atlantic 
right whale and take appropriate action.
     If underway, all vessels must steer a course away from any 
sighted North Atlantic right whale at 10 knots or less such that the 
500-m minimum separation distance requirement is not violated. If a 
North Atlantic right whale, or a large whale that cannot be confirmed 
as a species other than a North Atlantic right whale, is sighted within 
500 m of an underway vessel, that vessel must shift the engine to 
neutral. Engines will not be engaged until the whale has moved outside 
of the vessel's path and beyond 500 m. If a whale is observed but 
cannot be confirmed as a species other than a North Atlantic right 
whale, the vessel operator must assume that it is a North Atlantic 
right whale and take appropriate action.
     All vessels must maintain a minimum separation distance of 
100 m from sperm whales and non-North Atlantic right whale baleen 
whales. If one of these species is sighted within 100 m of an underway 
vessel, that vessel must shift the engine to neutral. Engines will not 
be engaged until the whale has moved outside of the vessel's path and 
beyond 100 m.
     All vessels must, to the maximum extent practicable, 
attempt to maintain a minimum separation distance of 50 m from all 
delphinoid cetaceans and pinnipeds, with an exception made for those 
that approach the vessel (e.g., bow-riding dolphins). If a delphinoid 
cetacean or pinniped is sighted within 50 m of an underway vessel, that 
vessel must shift the engine to neutral (again, with an exception made 
for those that approach the vessel). Engines will not be engaged until 
the animal(s) has moved outside of the vessel's path and beyond 50 m.
     When a marine mammal(s) is sighted while a vessel is 
underway, the vessel must take action as necessary to avoid violating 
the relevant separation distances (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 a marine mammal(s) is 
sighted within the relevant separation distance, the vessel must reduce 
speed and shift the engine to neutral, not engaging the engine(s) until 
the animal(s) is clear of the area. This does not apply to any vessel 
towing gear or any situation where respecting the relevant separation 
distance would be unsafe (i.e., any situation where the vessel is 
navigationally constrained).
     All vessels underway must not divert or alter course in 
order to approach any marine mammal.
     For in-water construction heavy machinery activities other 
than impact or vibratory pile driving, if a marine mammal in on a path 
towards or comes within 10 m of equipment, Revolution Wind must cease 
operations until the marine mammal has moved more than 10 m on a path 
away from the activity to avoid direct interaction with equipment.
     Revolution Wind must submit a North Atlantic right whale 
vessel strike avoidance plan 180 days prior to commencement of vessel 
use. The plan would, at minimum, describe how PAM, in combination with 
visual observations, would be conducted to ensure the transit corridor 
is clear of right whales. The plan would also provide details on the 
vessel-based observer protocols on transiting vessels.

WTG and OSS Foundation Installation

    For WTG and OSS foundation installation, NMFS is proposing to 
include the following mitigation requirements, which are described in 
detail below: seasonal and daily restrictions; the use of noise 
abatement systems; the use of PSOs and PAM operators; the 
implementation of clearance and shutdown zones, and the use of soft-
start.
Seasonal and Daily Restrictions
    No foundation impact pile driving activities would occur January 1 
through April 30. Based on the best available information (Roberts and 
Halpin, 2022), the highest densities of North Atlantic right whales in 
the project area are expected during the months of January through 
April. NMFS is requiring this seasonal work restriction to minimize the 
potential for North Atlantic right whales to be exposed to noise 
incidental to impact pile driving of monopiles, which is

[[Page 79133]]

expected to greatly reduce the number of takes of North Atlantic right 
whales.
    No more than three foundation monopiles would be installed per day. 
Monopiles would be no larger than 15-m in diameter, representing the 
larger end of the tapered 7/15-m monopile design. For all monopiles, 
the minimum amount of hammer energy necessary to effectively and safely 
install and maintain the integrity of the piles must be used. Hammer 
energies must not exceed 4,000 kJ.
    Revolution Wind has requested authorization to initiate pile 
driving during nighttime when detection of marine mammals is visually 
challenging. To date, Revolution Wind has not submitted a plan 
containing the information necessary, including evidence, that their 
proposed systems are capable of detecting marine mammals, particularly 
large whales, at night and at distances necessary to ensure mitigation 
measures are effective. The available information on traditional night 
vision technologies demonstrates that there is a high degree of 
uncertainty in reliably detecting marine mammals at night at the 
distances necessary for this project (Smultea et al., 2021). Therefore, 
at this time, NMFS plans to only allow Revolution Wind to initiate pile 
driving during daylight hours, and prohibit Revolution Wind from 
initiating pile driving earlier than one hour after civil sunrise or 
later than 1.5 hours before civil sunset. We are, however, proposing to 
encourage and allow Revolution Wind the opportunity to further 
investigate and test advanced technology and detection systems to 
support their request. NMFS is proposing to condition the LOA such that 
nighttime pile driving would only be allowed if Revolution Wind submits 
an Alternative Monitoring Plan (as part of the Pile Driving and Marine 
Mammal Monitoring Plan) to NMFS for approval that proves the efficacy 
of their night vision devices (e.g., mounted thermal/IR camera systems, 
hand-held or wearable night vision devices (NVDs), infrared (IR) 
spotlights) in detecting protected marine mammals prior to making a 
determination in the final rule. The plan must include a full 
description of the proposed technology, monitoring methodology, and 
supporting data demonstrating the reliability and effectiveness of the 
proposed technology in detecting marine mammal(s) within the clearance 
and shutdown zones for monopiles before and during impact pile driving. 
The Plan should identify the efficacy of the technology at detecting 
marine mammals in the clearance and shutdowns under all the various 
conditions anticipated during construction, including varying weather 
conditions, sea states, and in consideration of the use of artificial 
lighting.
Noise Abatement Systems
    Revolution Wind would employ noise abatement systems (NAS), also 
known as noise attenuation systems, during all impact pile driving of 
monopiles to reduce the sound pressure levels that are transmitted 
through the water in an effort to reduce ranges to acoustic thresholds 
and minimize any acoustic impacts resulting from impact pile driving. 
Revolution Wind would be required to employ a big double bubble curtain 
or a combination of two or more NAS during these activities, as well as 
the adjustment of operational protocols to minimize noise levels.
    Two categories of NAS exist: primary and secondary. A primary NAS 
would be used to reduce the level of noise produced by the pile driving 
activities at the source, typically through adjustments on to the 
equipment (e.g., hammer strike parameters). Primary NAS are still 
evolving and will be considered for use during mitigation efforts when 
the NAS has been demonstrated as effective in commercial projects. 
However, as primary NAS are not fully effective at eliminating noise, a 
secondary NAS would be employed. The secondary NAS is a device or group 
of devices that would reduce noise as it was transmitted through the 
water away from the pile, typically through a physical barrier that 
would reflect or absorb sound waves and, therefore reducing the 
distance the higher energy sound propagates through the water column. 
Together, these systems must reduce noise levels to the lowest level 
practicable with the goal of not exceeding measured ranges to Level A 
harassment and Level B harassment isopleths corresponding to those 
modeled assuming 10-dB sound attenuation, pending results of sound 
field verification (SFV) (see the Acoustic Monitoring for Sound Field 
and Harassment Isopleth Verification section).
    Noise abatement systems, such as bubble curtains, are 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 et al., 2016; Koschinski and L[uuml]demann, 
2013). Bubble curtains vary in terms of the sizes of the bubbles and 
those with larger bubbles tend to perform a bit better and more 
reliably, particularly when deployed with two separate rings (Bellmann, 
2014; Koschinski and L[uuml]demann, 2013; Nehls et al., 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. Secondary NAS that may be used by Revolution 
Wind include a big bubble curtain (BBC), a hydro-sound damper (HSD), or 
an AdBm Helmholz resonator (Elzinga et al., 2019). See Appendix B 
(Protected Species Mitigation and Monitoring Plan (PSMMP)) of the ITA 
application for more information on these systems (Revolution Wind, 
2022b). If a single system is used, it must be a double big bubble 
curtain (dBBC). Other systems (e.g., noise mitigation screens) are not 
considered feasible for the Revolution Wind project as they are in 
their early stages of development and field tests to evaluate 
performance and effectiveness have not been completed. Should the 
research and development phase of these newer systems demonstrate 
effectiveness, as part of adaptive management, Revolution Wind may 
submit data on the effectiveness of these systems and request approval 
from NMFS to use them during pile driving.
    If a bubble curtain is used (single or double), [Oslash]rsted would 
be required to maintain the following operational parameters: The 
bubble curtain(s) must distribute air bubbles using a target air flow 
rate of at least 0.5 m\3\/(min*m), and must distribute bubbles around 
100 percent of the piling perimeter for the full depth of the water 
column. The lowest bubble ring must be in contact with the seafloor for 
the full circumference of the ring, and the weights attached to the 
bottom ring must ensure 100-percent seafloor contact; no parts of the 
ring or other

[[Page 79134]]

objects should prevent full seafloor contact. Revolution Wind must 
require that construction contractors train personnel in the proper 
balancing of airflow to the bubble ring, and must require that 
construction contractors submit an inspection/performance report for 
approval by Revolution Wind within 72 hours following the performance 
test. Corrections to the attenuation device to meet the performance 
standards must occur prior to impact driving of monopiles. If 
Revolution Wind uses a noise mitigation device in addition to a BBC, 
similar quality control measures would be required.
    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. D[auml]hne et al. (2017) found that single bubble 
curtains that reduce sound levels by 7 to 10 dB reduced the overall 
sound level by approximately 12 dB when combined as a double bubble 
curtain for 6-m steel monopiles in the North Sea. During installation 
of monopiles (~8 m) for more than 150 WTGs in comparable water depths 
(>25 m) and conditions in Europe indicate that attenuation of 10 dB is 
readily achieved (Bellmann, 2019; Bellmann et al., 2020) using single 
BBCs for noise attenuation. 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 installation 
using a dBBC and the other installation using no noise abatement system 
(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 9-15 dB. Again, NMFS would require Revolution 
Wind to apply a dBBC, or a single BBC coupled with an additional noise 
mitigation device, to ensure sound generated from the project does not 
exceed that modeled (assuming 10-dB reduction) at given ranges to 
harassment isopleths, and to minimize noise levels to the lowest level 
practicable. Double BBCs are successfully and widely applied across 
European wind development efforts, and are known to reduce noise levels 
more than single BBC alone (e.g., Bellman et al., 2020). Revolution 
Wind anticipates, and NMFS agrees, that the use of a noise abatement 
system would likely 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 for impact 
pile driving of monopiles (refer back to the Estimated Take, Proposed 
Mitigation, and Proposed Monitoring and Reporting sections).
Use of PSOs and PAM Operators
    As described above, Revolution Wind would be required to use PSOs 
and acoustic PSOs (i.e., PAM operators) during all foundation 
installation activities. At minimum, four PSOs would be actively 
observing marine mammals before, during, and after pile driving. At 
least two PSOs would be stationed on the pile driving vessel and at 
least two PSOs would be stationed on a secondary, dedicated PSO vessel. 
The dedicated PSO vessel would be located at the outer edge of the 2.3 
km (in the summer; 4.4 km in the winter) large whale clearance zone 
(unless modified by NMFS based on SFV). Concurrently, at least one PAM 
operator would be actively monitoring for marine mammals before, 
during, and after pile driving. More details on PSO and PAM operator 
requirements can be found in the Proposed Monitoring and Reporting 
section.
    Furthermore, all crew and personnel working on the Revolution Wind 
project would be required to maintain situational awareness of marine 
mammal presence (discussed further above) and would be required to 
report any sightings to the PSOs.
Clearance and Shutdown Zones
    NMFS is proposing to require the establishment of both clearance 
and shutdown zones during all impact pile driving of WTG and OSS 
foundation piles, which would be monitored by visual PSOs and PAM 
operators before, during and after pile driving. Prior to the start of 
impact pile driving activities, Revolution Wind would clear the area of 
marine mammals, per the clearance zones in Table 34, to minimize the 
potential for and degree of harassment.
    The purpose of ``clearance'' of a particular zone is to prevent 
potential instances of auditory injury and more severe behavioral 
disturbance or, in the case of North Atlantic right whales, avoid and 
minimize behavioral disturbance to the maximum extent practicable (for 
North Atlantic right whales, the clearance and shutdown zones are set 
to any distance; see Table 34) by delaying the commencement of impact 
pile driving if marine mammals are detected within certain pre-defined 
distances from the pile being installed.
    PSOs would visually monitor for marine mammals for a minimum of 60 
minutes immediately prior to commencement of pile driving, while PAM 
operators would review data from at least 24 hours prior to pile 
driving and actively monitor hydrophones for 60 minutes immediately 
prior to pile driving. Prior to initiating soft-start procedures, all 
clearance zones must be visually confirmed to be free of marine mammals 
for 30 minutes immediately prior to starting a soft-start of pile 
driving. If a marine mammal is observed entering or within the relevant 
clearance zone prior to the initiation of impact pile driving 
activities, pile driving must be delayed and will not begin until 
either the marine mammal(s) has voluntarily left the specific clearance 
zones and have been visually or acoustically confirmed beyond that 
clearance zone, or, when specific time periods have elapsed with no 
further sightings or acoustic detections have occurred (i.e., 15 
minutes for small odontocetes and 30 minutes for all other marine 
mammal species).
    Mitigation zones related to impact pile driving activities were 
created around two different seasonal periods in consideration of the 
different seasonal sound speed profiles that were used in JASCO's 
underwater sound propagation modeling, including summer (May through 
November) and winter (December) (Table 34). In addition to the 
clearance and shutdown zones that would be monitored both visually and 
acoustically, NMFS is proposing to establish a minimum visibility zone 
to ensure that marine mammals are visually detected prior to 
commencement of pile driving. The minimum visibility zone would extend 
2,300 m from the pile during summer months and 4,400 m during December 
(Table 34). These values correspond to the maximum low-frequency 
cetacean (i.e., baleen whale) distances to the Level A harassment 
isopleths assuming three monopiles are driven in a day, rounded up to 
the nearest hundred. The entire minimum visibility zone must be visible 
(i.e., not obscured by dark, rain, fog, etc.) for a full 30 minutes 
immediately prior to commencing impact pile driving. For North Atlantic 
right whales, there is an additional requirement that the clearance 
zone may only be declared clear if no confirmed North Atlantic right 
whale acoustic detections (in addition to visual) have occurred during 
the 60-minute

[[Page 79135]]

monitoring period. Any large whale sighted by a PSO or acoustically 
detected by a PAM operator that cannot be identified as a non-North 
Atlantic right whale must be treated as if it were a North Atlantic 
right whale.
    The purpose of a shutdown is to prevent a specific acute impact, 
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 shutdown zone (Table 34) after impact 
pile driving has begun, the PSO will request a temporary cessation of 
impact pile driving. In situations when shutdown is called for but 
Revolution 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 creates risk of injury or loss of life for individuals, 
reduced hammer energy must be implemented when the lead engineer 
determines it is practicable. Specifically, pile refusal or pile 
instability could result in not being able to shut down pile driving 
immediately. Pile refusal occurs when the pile driving sensors indicate 
the pile is approaching refusal, and a shut-down would lead to a stuck 
pile which then poses an imminent risk of injury or loss of life to an 
individual, or risk of damage to a vessel that creates risk for 
individuals. Pile instability occurs when the pile is unstable and 
unable to stay standing if the piling vessel were to ``let go.'' During 
these periods of instability, the lead engineer may determine a 
shutdown is not feasible because the shutdown combined with impending 
weather conditions may require the piling vessel to ``let go'' which 
then poses an imminent risk of injury or loss of life to an individual, 
or risk of damage to a vessel that creates risk for individuals. In 
these situations, Revolution Wind must reduce hammer energy to the 
lowest level practicable.
    After shutdown, impact pile driving may be reinitiated once all 
clearance zones are clear of marine mammals for the minimum species-
specific periods (15 minutes for small odontocetes and 30 minutes for 
all other marine mammal species). If pile driving has been shut down 
due to the presence of a North Atlantic right whale, pile driving may 
not restart until the North Atlantic right whale is no longer observed 
or 30 minutes has elapsed since the last detection. In cases where 
these criteria are not met, pile driving may restart only if necessary 
to maintain pile stability, at which time Revolution Wind must use the 
lowest hammer energy practicable to maintain stability. Upon re-
starting pile driving, soft start protocols must be followed.
    The clearance and shutdown zone sizes vary by species and are shown 
in Table 34. All distances to the perimeter of clearance zones are the 
radii from the center of the pile. Pursuant to the proposed adaptive 
management provisions, Revolution Wind may request modification to 
these zone sizes pending results of sound field verification (see 
Proposed Monitoring and Reporting section). Any changes to zone size 
would require NMFS' approval.

           Table 34--Clearance, Shutdown, Minimum Visibility, and Level B Harassment Zones During Impact Pile Driving in Summer and Winter \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                  Monitoring details                                                    Zone sizes for impact piling  (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                          North Atlantic       Large whales         Delphinids       Harbor  porpoises        Seals
                                                           right whales    -----------------------------------------------------------------------------
                    Foundation type                    --------------------
                                                           WTG       OSS       WTG       OSS       WTG       OSS       WTG       OSS      WTG      OSS
--------------------------------------------------------------------------------------------------------------------------------------------------------
Clearance Zone........................................     any distance        2,300     1,600   \2\ NAS       NAS     1,400       900      500      400
                                                                             (4,400)   (2,700)                       (2,400)   (1,300)    (900)    (400)
--------------------------------------------------------------------------------------------------------------------------------------------------------
PAM Clearance Zone....................................     3,900     4,100
                                                         (4,300)   (4,700)                                       n/a
--------------------------------------------------------------------------------------------------------------------------------------------------------
Shutdown Zone.........................................     any distance        2,300     1,600       NAS       NAS     1,400       900      500      400
                                                                             (4,400)   (2,700)                       (2,400)   (1,300)    (900)    (400)
--------------------------------------------------------------------------------------------------------------------------------------------------------
PAM Shutdown Zone.....................................     3,900     4,100
                                                         (4,400)   (4,700)                                       n/a
--------------------------------------------------------------------------------------------------------------------------------------------------------
Minimum Visibility Zone...............................                                WTG: 2,300 (4,400) OSS: 1,600 (2,700)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level B Harassment Zone...............................                                WTG: 3,833 (4,271) OSS: 4,100 (4,698)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Winter (i.e., December) distances are presented in parentheses.
\2\ NAS (noise abatement system) means that the zone is small enough that it would be encompassed by the bubble curtain.

Soft-Start
    The use of a soft start procedure is believed to provide additional 
protection to marine mammals by warning them, or providing them with a 
chance to leave the area prior to the hammer operating at full 
capacity. Soft start typically involves initiating hammer operation at 
a reduced energy level (relative to full operating capacity) followed 
by a waiting period. Revolution Wind must utilize a soft start protocol 
for impact pile driving of monopiles 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 a reduction 
in energy for any given hammer because of variation across drivers. 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, Revolution Wind 
will target less than 20 percent of the total hammer energy for the 
initial hammer strikes during soft start. Soft start will be required 
at the beginning of each day's monopile installation, and at any time 
following a cessation of impact pile driving of 30 minutes or longer. 
If a marine mammal is detected within or about to enter the applicable 
clearance zones prior to the beginning of soft-start procedures, impact 
pile driving would be delayed until the animal has been visually 
observed exiting the clearance zone or until a specific time period has 
elapsed with no further sightings (i.e., 15 minutes for small 
odontocetes and 30 minutes for all other species).

[[Page 79136]]

Cofferdam or Casing Pipe Installation and Removal

    For cofferdam or casing pipe installation and removal, NMFS is 
proposing to include the following mitigation requirements, which are 
described in detail below: daily restrictions; the use of PSOs; the 
implementation of clearance and shutdown zones; and the use of soft-
start if a pneumatic impact hammer is used. Given the short duration of 
work, relatively small harassment zones if a pneumatic hammer is used, 
and lower noise levels during vibratory driving, NMFS is not proposing 
to require PAM or noise abatement system use during these activities.
Seasonal and Daily Restrictions
    Revolution Wind has proposed to construct the cofferdams or casing 
pipe scenario within the first year of the effective period of the 
regulations and LOA. NMFS is not requiring any seasonal work 
restrictions for landfall construction in this proposed rule due to the 
relatively short duration of work (i.e., low associated impacts). 
Revolution Wind would be required, however, to conduct vibratory pile 
driving associated with cofferdam installation and pneumatic hammering 
of casing pipes during daylight hours only. Although North Atlantic 
right whales do migrate in coastal waters, they are not expected to 
occur in Narragansett Bay where work would be occurring. The distance 
to the Level B harassment isopleth (9.74 km) for installation of steel 
sheet piles and the maximum distance to the Level A isopleth (3.95 km) 
for installation of a casing pipe do not extend beyond the mouth of 
Narragansett Bay; thus, it is unlikely that right whales (or most 
species of marine mammals considered here) would be exposed to 
vibratory pile driving during cofferdam or goal post sheet pile 
installation at levels close to the 120 dB Level B harassment 
threshold, or pneumatic hammering at Level A harassment thresholds.
Use of PSOs
    Prior to the start of vibratory pile driving or pneumatic hammering 
activities, at least two PSOs located at the best vantage points would 
monitor the clearance zone for 30 minutes, continue monitoring during 
pile driving or pneumatic hammering, and for 30 minutes following 
cessation of either activity. The clearance zones must be fully visible 
for at least 30 minutes and all marine mammal(s) must be confirmed to 
be outside of the clearance zone for at least 30 minutes immediately 
prior to initiation of either activity.
Clearance and Shutdown Zones
    Revolution Wind would establish clearance and shutdown zones for 
vibratory pile driving activities associated with cofferdam 
installation (Table 35) and pneumatic hammering for casing pipe 
installation (Table 36). If a marine mammal is observed entering or is 
observed within the respective zones, activities will not commence 
until the animal has exited the zone or a specific amount of time has 
elapsed since the last sighting (i.e., 30 minutes for large whales and 
15 minutes for dolphins, porpoises, and pinnipeds). If a marine mammal 
is observed entering or within the respective shutdown zone after 
vibratory pile driving or pneumatic hammering has begun, the PSO will 
call for a temporary cessation of the activity. Pile driving or 
hammering must not be restarted until either the marine mammal(s) has 
voluntarily left the specific clearance zones and has been visually 
confirmed beyond that clearance zone, or, when specific time periods 
have elapsed with no further sightings or acoustic detections have 
occurred (i.e., 15 minutes for small odontocetes and 30 minutes for all 
other marine mammal species). Because a vibratory hammer can grip a 
pile without operating, pile instability should not be a concern and no 
caveat for re-starting pile driving due to pile instability is 
proposed.

      Table 35--Distances to Harassment Thresholds and Mitigation Zones During Vibratory Sheet Pile Driving
----------------------------------------------------------------------------------------------------------------
                                                      Level A
                                                    harassment        Level B        Clearance    Shutdown  zone
              Marine mammal species                (SELcum)  (m)    harassment       zone  (m)          (m)
                                                                        (m)
----------------------------------------------------------------------------------------------------------------
                                             Low-frequency cetaceans
----------------------------------------------------------------------------------------------------------------
Fin whale *.....................................               5           9,740             100             100
Minke whale.....................................               5           9,740             100             100
Sei whale *.....................................               5           9,740             100             100
Humpback whale..................................               5           9,740             100             100
North Atlantic right whale *....................               5           9,740             100             100
Blue whale *....................................               5           9,740             100             100
----------------------------------------------------------------------------------------------------------------
                                             Mid-frequency cetaceans
----------------------------------------------------------------------------------------------------------------
Sperm whale *...................................  ..............           9,740             100             100
Atlantic white-sided dolphin....................  ..............           9,740              50              50
Atlantic spotted dolphin........................  ..............           9,740              50              50
Common dolphin..................................  ..............           9,740              50              50
Risso's dolphin.................................  ..............           9,740              50              50
Bottlenose dolphin..............................  ..............           9,740              50              50
Pilot whales....................................  ..............           9,740              50              50
----------------------------------------------------------------------------------------------------------------
                                            High-frequency cetaceans
----------------------------------------------------------------------------------------------------------------
Harbor porpoise.................................             190           9,740         \1\ 200         \1\ 200
----------------------------------------------------------------------------------------------------------------
                                           Phocid Pinnipeds (in water)
----------------------------------------------------------------------------------------------------------------
Gray seal.......................................              10           9,740              50              50

[[Page 79137]]

 
Harbor seal.....................................              10           9,740              50              50
----------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act
\1\ Distance has been increased from 100 m, as proposed by Revolution Wind, to ensure the clearance and shutdown
  zones are larger than the Level A harassment zone (190 m).


        Table 36--Distances to Harassment Thresholds and Mitigation Zones During Casing Pipe Installation
----------------------------------------------------------------------------------------------------------------
                                                      Level A
                                                    harassment        Level B        Clearance    Shutdown  zone
           Marine mammal hearing group             (SELcum)  (m)    harassment       zone  (m)          (m)
                                                                        (m)
----------------------------------------------------------------------------------------------------------------
Low-frequency...................................           3,870             920           3,900           3,900
Mid-frequency...................................             230             920             250             250
High-frequency..................................           3,950             920           4,000           4,000
Phocid pinnipeds................................           1,290             920           1,300           1,300
----------------------------------------------------------------------------------------------------------------

UXO/MEC Detonations

    For UXO/MEC detonations, NMFS is proposing to include the following 
mitigation requirements, which are described in detail below: As Low as 
Reasonably Practical Approach (ALARP); seasonal and daily restrictions; 
the use of noise abatement systems; the use of PSOs and PAM operators 
to visually and acoustically monitor for marine mammals; and the 
implementation of clearance zones.
As Low as Reasonably Practicable (ALARP) Approach
    For any UXOs/MECs that require removal, Revolution Wind would be 
required to implement the As Low as Reasonably Practicable (ALARP) 
process. This process would require Revolution Wind to undertake 
``life-and-shift'' (i.e., physical removal and then lead up to in situ 
disposal), which would include low-order (deflagration) to high-order 
(detonation) methods of removal. Another potential approach involve the 
cutting of the UXO/MEC to extract any explosive components. 
Implementing the ALARP approach would minimize potential impacts to 
marine mammals, as UXOs/MECs would only be detonated as a last resort.
Seasonal and Daily Restrictions
    Revolution Wind would be limited to only detonating a total of 13 
UXOs/MECs between May 1 and October 31 to reduce impacts to North 
Atlantic right whales during peak occurrence periods. Furthermore, UXO/
MEC detonation would be limited to daylight hours only to ensure that 
visual PSOs can confirm appropriate clearance of the site prior to 
detonation events.
Noise Abatement Systems
    Revolution Wind would be required to use a noise abatement system 
during all UXO/MEC detonations, should detonations be determined to be 
necessary. Although the exact level of noise attenuation that can be 
achieved by noise abatement systems is unknown, available data from 
Bellmann et al. (2020) and Bellmann and Betke (2021) provide a 
reasonable expectation that the noise abatement systems would be able 
to achieve at least 10-dB attenuation. SFV would be required for all 
detonation events to verify the modeled distances, assuming 10-dB 
attenuation, are representative of the sound fields generated during 
detonations. This level of noise reduction would provide substantial 
reductions in impact zones for low-frequency cetaceans such as the 
North Atlantic right whale. For example, assuming the largest UXO/MEC 
charge weight (454 kg; E12) at a depth of 45 m, 10-dB of attenuation 
reduces the Level A harassment (PTS) zone from 243 km\2\ to 
approximately 45 km\2\ (Table 45 in the ITA application). The Level B 
harassment zone, given the same parameters, would be decreased from 
1,158 km\2\ to 445 km\2\ (Table 47 in the ITA application). However, 
and as previously stated in this notice, Revolution Wind does not 
expect that all 13 of the potential UXOs/MECs would be of the largest 
charge weight; this weight was used as a conservative option in 
estimating exposures and take of marine mammals.
Use of PSOs and PAM Operators
    Prior to the UXO/MEC detonation, at least two PSOs per observing 
platform (i.e., vessels, plane) located at the best vantage points 
would monitor the clearance zone for 60 minutes, continue monitoring 
during the detonation, and for 30 minutes following the event. The 
clearance zones must be fully visible for at least 60 minutes and all 
marine mammal(s) must be confirmed to be outside of the clearance zone 
for at least 30 minutes immediately prior to initiation of either 
activity. PAM must also be conducted for at least 60 minutes prior to 
detonation and the zone must be acoustically clear during this time.
Clearance Zones
    Revolution Wind proposed to clear a 3.78-km radius zone around the 
detonation site prior to detonations using both visual and acoustic 
monitoring methods. This distance represents the modeled Level A (PTS) 
harassment zone for low-frequency cetaceans (i.e., large whales) 
assuming the largest 454-kg charge weight and use of a bubble curtain 
(Table 37). However, NMFS is proposing to require more protective zone 
sizes in order to ensure the least practicable adverse impact, which 
includes minimizing the potential for TTS. As stated above, it is 
currently not known how easily Revolution Wind will be able to identify 
UXO/MEC charge weights in the field. For this reason, NMFS proposes to 
require Revolution Wind to clear a zone extending 10 km for large 
whales, 2 km for delphinids, 10 km for harbor porpoises, and 5 km for 
seals (Table 37). These zones are based on (but not equal to) the 
largest TTS threshold distances for a 454-kg charge at any site 
modeled. However, NMFS notes that these zone

[[Page 79138]]

sizes may be adjusted based on SFV and confirmation of UXO/MEC/doner 
charge sizes. Moreover, if Revolution Wind indicates to NMFS they will 
be able to easily and reliably identify charge weights in the field, 
NMFS would develop clearance zones in the final rule for each charge 
weight analyzed.
    If a marine mammal is observed entering or within the clearance 
zone prior to denotation, the activity would be delayed. Only when the 
marine mammals have been confirmed to have voluntarily left the 
clearance zones and been visually confirmed to be beyond the clearance 
zone, or when 60 minutes have elapsed without any redetections for 
whales (including the North Atlantic right whale) or 30 minutes have 
elapsed without any redetections of delphinids, harbor porpoises, or 
seals may detonation occur.

 Table 37--Largest Modeled Harassment and Clearance Zones for UXO/MEC Detonation of E12 (454 kg) Charge Assuming
                                              10-dB Noise Abatement
----------------------------------------------------------------------------------------------------------------
                                                              Distances to zones for E12 (454 kg) UXO/MEC charge
                                                                                  weight \1\
                                                            ----------------------------------------------------
                   Marine mammal species                          Level A
                                                                harassment          Level B          Clearance
                                                              clearance zone    harassment zone        zones
                                                                    (m)               (m)
----------------------------------------------------------------------------------------------------------------
                                             Low-frequency cetaceans
----------------------------------------------------------------------------------------------------------------
Fin whale *................................................             3,780             11,900          10,000
Minke whale................................................
Sei whale *................................................
Humpback whale.............................................
North Atlantic right whale *...............................
Blue whale *...............................................
----------------------------------------------------------------------------------------------------------------
                                             Mid-frequency cetaceans
----------------------------------------------------------------------------------------------------------------
Sperm whale *..............................................               461              2,550           2,000
Atlantic white-sided dolphin...............................
Atlantic spotted dolphin...................................
Common dolphin.............................................
Risso's dolphin............................................
Bottlenose dolphin.........................................
Long-finned pilot whale....................................
----------------------------------------------------------------------------------------------------------------
                                            High-frequency cetaceans
----------------------------------------------------------------------------------------------------------------
Harbor porpoise............................................             6,200             14,100          10,000
----------------------------------------------------------------------------------------------------------------
                                              Pinnipeds (in water)
----------------------------------------------------------------------------------------------------------------
Gray seal..................................................             1,600              6,990           5,000
Harbor seal................................................
----------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.
\1\ At time of preparing this proposed rule, Revolution Wind has not provided NMFS evidence they will be able to
  reliably determine the charge weight of any UXO/MEC that must be detonated; therefore, NMFS assumes all UXO/
  MECs could be of the largest size modeled. If Revolution Wind provides information they can detect charge
  weights in the field prior to issuance of the final rule, if issued, NMFS may modify the clearance zone to
  ones based on charge weights distances to PTS and TTS. Distances to PTS and TTS thresholds have been
  identified by Revolution Wind in Appendix B of their application.

HRG Surveys

    For HRG surveys, NMFS is proposing to include the following 
mitigation requirements, which are described in detail below, for all 
HRG survey activities using boomers, sparkers, and CHIRPs: the use of 
PSOs; the implementation of clearance, shutdown, and vessel separation 
zones; and ramp-up of survey equipment.
    There are no mitigation measures prescribed for sound sources 
operating at frequencies greater than 180 kHz, as these would be 
expected to fall outside of marine mammal hearing ranges and not result 
in harassment; however, all HRG survey vessels would be subject to the 
aforementioned vessel strike avoidance measures described earlier in 
this section. Furthermore, due to the frequency range and 
characteristics of some of the sound sources, shutdown, clearance, and 
ramp-up procedures are not proposed to be conducted during HRG surveys 
utilizing only non-impulsive sources (e.g., Ultra-Short BaseLine (USBL) 
and other parametric sub-bottom profilers), with exception to usage of 
CHIRPS and other non-parametric sub-bottom profilers. PAM would not be 
required during HRG surveys. While NMFS agrees that PAM can be an 
important tool for augmenting detection capabilities in certain 
circumstances, its utility in further reducing impacts during HRG 
survey activities is limited. We have provided a thorough description 
of our reasoning for not requiring PAM during HRG surveys in several 
Federal Register notices (e.g., 87 FR 40796, July 8, 2022; 87 FR 52913, 
August 3, 2022; 87 FR 51356, August 22, 2022).
Seasonal and Daily Restrictions
    Given the potential impacts to marine mammals from exposure to HRG 
survey noise sources are relatively minor (e.g., limited to Level B 
harassment) and that the distances to the Level B harassment isopleth 
is very small (maximum distance is 141 m), NMFS is not proposing to 
implement any seasonal or time-of-day restrictions for HRG surveys.

[[Page 79139]]

    Although no temporal restrictions are proposed, NMFS would require 
Revolution Wind to deactivate acoustic sources during periods where no 
data is being collected, except as determined necessary for testing. 
Any unnecessary use of the acoustic source would be avoided.
Use of PSOs
    During all HRG survey activities using boomers, sparkers, and 
CHIRPS, one PSO would be required to monitor during daylight hours and 
two would be required to monitor during nighttime hours, per vessel. 
PSOs would begin visually monitoring 30 minutes prior to the initiation 
of the specified acoustic source (i.e., ramp-up, if applicable) through 
30 minutes after the use of the specified acoustic source has ceased. 
PSOs would be required to monitor the appropriate clearance and 
shutdown zones. These zones would be based around the radial distance 
from the acoustic source and not from the vessel.
Clearance, Shutdown, and Vessel Separation Zones
    Revolution Wind would be required to implement a 30-minute 
clearance period of the clearance zones (Table 38) immediately prior to 
the commencing of the survey, or when there is more than a 30-minute 
break in survey activities and PSOs have not been actively monitoring. 
The clearance zones would be monitored by PSOs, using the appropriate 
visual technology. If a marine mammal is observed within a clearance 
zone during the clearance period, ramp-up (described below) may not 
begin until the animal(s) has been observed voluntarily 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). In any 
case when the clearance process has begun in conditions with good 
visibility, including via the use of night vision equipment (IR/thermal 
camera), and the Lead PSO has determined that the clearance zones are 
clear of marine mammals, survey operations would be allowed to commence 
(i.e., no delay is required) despite periods of inclement weather and/
or loss of daylight.
    Once the survey has commenced, Revolution Wind would be required to 
shut down boomers, sparkers, and CHIRPs if a marine mammal enters a 
respective shutdown zone (Table 38). In cases when the shutdown zones 
become obscured for brief periods due to inclement weather, survey 
operations would be allowed to continue (i.e., no shutdown is required) 
so long as no marine mammals have been detected. The use of boomers, 
sparkers, and CHIRPS would not be allowed to commence or resume until 
the animal(s) has been confirmed to have left the shutdown zone or 
until a full 15 minutes (for small odontocetes and seals) or 30 minutes 
(for all other marine mammals) have elapsed with no further sighting. 
Any large whale sighted by a PSO within 1,000 m of the boomers, 
sparkers, and CHIRPs that cannot be identified as a non-North Atlantic 
right whale would be treated as if it were a North Atlantic right 
whale.
    The shutdown requirement would be waived for small delphinids of 
the following genera: Delphinus, Stenella, Lagenorhynchus, 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 would not be 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), the PSOs would use their best 
professional judgment in making the decision to call for a shutdown. 
Shutdown would be required if a delphinid that belongs to a genus other 
than those specified is detected in the shutdown zone.
    If a boomer, sparker, or CHIRP is shut down for reasons other than 
mitigation (e.g., mechanical difficulty) for less than 30 minutes, it 
would be allowed to be activated again without ramp-up only if (1) PSOs 
have maintained constant observation, and (2) no additional detections 
of any marine mammal occurred within the respective shutdown zones. If 
a boomer, sparker, or CHIRP was shut down for a period longer than 30 
minutes, then all clearance and ramp-up procedures would be required, 
as previously described.

                  Table 38--Harassment Threshold Ranges and Mitigation Zones During HRG Surveys
----------------------------------------------------------------------------------------------------------------
                                                Level B harassment zone (m)
           Marine mammal species            ----------------------------------  Clearance zone    Shutdown zone
                                              Boomer/sparker       CHIRPs             (m)              (m)
----------------------------------------------------------------------------------------------------------------
                                             Low-frequency cetaceans
----------------------------------------------------------------------------------------------------------------
Fin whale.*                                               141              48               100              100
Minke whale.                                                                                100              100
Sei whale.*                                                                                 100              100
Humpback whale.                                                                             100              100
North Atlantic right whale.*                                                                500              500
Blue whale.*                                                                                100              100
----------------------------------------------------------------------------------------------------------------
                                             Mid-frequency cetaceans
----------------------------------------------------------------------------------------------------------------
Sperm whale.*                                             141              48               100              100
Atlantic white-sided dolphin.                                                               100              n/a
Atlantic spotted dolphin.                                                                   100              n/a
Common dolphin.                                                                             100              n/a
Risso's dolphin.                                                                            100              100
Bottlenose dolphin.                                                                         100              n/a
Long-finned pilot whale.                                                                    100              100
----------------------------------------------------------------------------------------------------------------
                                            High-frequency cetaceans
----------------------------------------------------------------------------------------------------------------
Harbor porpoise.                                          141              48               100              100
----------------------------------------------------------------------------------------------------------------

[[Page 79140]]

 
                                           Phocid Pinnipeds (in water)
----------------------------------------------------------------------------------------------------------------
Gray seal.                                                141              48               100              100
Harbor seal.
----------------------------------------------------------------------------------------------------------------
Note: n/a = no shutdown zone mitigation will be applied as these species are known to bow-ride.
* Denotes species is listed under the Endangered Species Act.

Ramp-Up
    At the start or restart of the use of boomers, sparkers, and/or 
CHIRPs, a ramp-up procedure would be required unless the equipment 
operates on a binary on/off switch. A ramp-up procedure, involving a 
gradual increase in source level output, is required at all times as 
part of the activation of the acoustic source when technically 
feasible. Operators would ramp up sources to half power for 5 minutes 
and then proceed to full power. Prior to a ramp-up procedure starting, 
the operator would have to notify the Lead PSO of the planned start of 
the ramp-up. This notification time would not be less than 60 minutes 
prior to the planned ramp-up activities as all relevant PSOs would need 
the appropriate 30 minute period to monitor prior to the initiation of 
ramp-up. Prior to ramp-up beginning, the operator must receive 
confirmation from the PSO that the clearance zone is clear of any 
marine mammals. All ramp-ups would be scheduled to minimize the overall 
time spent with the source being activated. The ramp-up procedure must 
be used at the beginning of HRG survey activities or after more than a 
30-minute break in survey activities using the specified HRG equipment 
to provide additional protection to marine mammals in or near the 
survey area by allowing them to vacate the area prior to operation of 
survey equipment at full power.
    Revolution Wind would not initiate ramp-up until the clearance 
process has been completed (see Clearance and Shutdown Zones section 
above). Ramp-up activities would be delayed if a marine mammal(s) 
enters its respective clearance zone. Ramp-up would only be reinitiated 
if the animal(s) has been observed exiting its respective shutdown zone 
or until additional time has elapsed with no further sighting (i.e., 15 
minutes for small odontocetes and seals, and 30 minutes for all other 
species).
ASV Use
    Should Revolution Wind use an ASV for HRG survey operations, the 
following measures would be implemented:
     When in use, the ASV would be within 800 m (2,625 ft) of 
the primary vessel while conducting survey operations;
     Two PSOs would be stationed aboard the mother vessel at 
the best vantage points to monitor the clearance and shutdown zones 
around the ASV;
     A dual thermal/high definition camera would be installed 
on the mother vessel, facing forward and angled in a direction to 
provide a field of view ahead of the vessel and around the ASV. PSOs 
would monitor the real-time camera output on hand-held tablets. A 
monitor would also be installed on the bridge, displaying the real-time 
image from the thermal/HD camera installed on the ASV itself, providing 
an additional forward field of view from the ASV;
     Night-vision goggles with thermal clip-ons, and a hand-
held spotlight would be used to monitor the ASV during survey 
operations during periods of reduced visibility (e.g., darkness, rain, 
fog).

Fishery Monitoring Surveys

Training
    All crew undertaking the fishery survey activities would be 
required to receive protected species identification training prior to 
activities occurring. Marine mammal monitoring must occur prior to, 
during, and after haul-back, and gear must not be deployed if a marine 
mammal is observed in the area. Trawl operations must only start after 
15 minutes of no marine mammal sightings within 1 nm of the sampling 
station.
Gear-Specific Best Management Practices (BMPs)
    During daytime sampling for the research trawl surveys, Revolution 
Wind must maintain visual monitoring efforts during the entire period 
of time that trawl gear is in the water from deployment to retrieval. 
If a marine mammal is sighted before the gear is removed from the 
water, the vessel must slow its speed and steer away from the observed 
animal(s).
    Revolution Wind would be required to undertake BMPs to reduce risks 
to marine mammals during trawl and trap surveys. These include:
     For research trawls, these specifically include limiting 
tow time to 20 minutes and monitoring for marine mammals throughout 
gear deployment, fishing, and retrieval. For ventless trap surveys, 
these include the breaking strength of all lines being less than 1,700 
pounds, the use of sinking line for groundlines, the hauling of 
sampling gear at least once every 30 days, and the removal of gear at 
the end of each sampling season;
     The permit number would be written clearly on buoy and any 
lines that go missing would be reported to NOAA Fisheries' Greater 
Atlantic Regional Fisheries Office (GARFO) Protected Resources Division 
as soon as possible;
     If marine mammals are sighted near the proposed sampling 
location, deployment of research trawl nets and ventless traps would be 
delayed until the marine mammal(s) has left the area;
     If a marine mammal is determined to be at risk of 
interaction with the deployed gear, all gear would be immediately 
removed; and
     If marine mammals are sighted in the vicinity within 15 
minutes prior to gear deployment and it is determined the risks of 
interaction are present regarding the research gear, the sampling 
station would either move to another location or suspend activities 
until there are no marine mammal sightings for 15 minutes within 1 nm.
    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures would provide the 
means of affecting the least practicable impact on the affected species 
or stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance.

[[Page 79141]]

Proposed Monitoring and Reporting

    In order to promulgate a rulemaking for an activity, section 
101(a)(5)(A) of the MMPA states that NMFS must set forth requirements 
pertaining to the monitoring and reporting of such taking. The MMPA 
implementing regulations at 50 CFR 216.104(a)(13) indicate that 
requests for authorizations must include the suggested means of 
accomplishing the necessary monitoring and reporting that will result 
in increased knowledge of the species and of the level of taking or 
impacts on populations of marine mammals that are expected to be 
present in the proposed action area. Effective reporting is critical 
both to compliance as well as ensuring that the most value is obtained 
from the required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the action; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and/or
     Mitigation and monitoring effectiveness.
    Separately, monitoring is also regularly used to support mitigation 
implementation, which is referred to as mitigation monitoring, and 
monitoring plans typically include measures that both support 
mitigation implementation and increase our understanding of the impacts 
of the activity on marine mammals.
    During Revolution Wind's construction activities, visual monitoring 
by NMFS-approved PSOs would be conducted before, during, and after 
impact pile driving, vibratory pile driving and pneumatic hammering, 
any UXO/MEC detonations, and HRG surveys. PAM would also be conducted 
during all impact pile driving and UXO/MEC detonations. Observations 
and acoustic detections by PSOs would be used to support the activity-
specific mitigation measures described above. Also, to increase 
understanding of the impacts of the activity on marine mammals, 
observers would record all incidents of marine mammal occurrence at any 
distance from the piling and pneumatic hammering locations, UXO/MEC 
detonation site, and during active HRG acoustic sources, and monitors 
would document all behaviors and behavioral changes, in concert with 
distance from an acoustic source. The required monitoring is described 
below, beginning with PSO measures that are applicable to all 
activities or monitoring, followed by activity-specific monitoring 
requirements.

Protected Species Observer Requirements

    Revolution Wind would be required to collect sighting data and 
behavioral response data related to construction activities for marine 
mammal species observed in the region of the activity during the period 
in which the activities occur using NMFS-approved visual and acoustic 
PSOs (see Proposed Mitigation section). All observers must be trained 
in marine mammal identification and behaviors, and are required to have 
no other construction-related tasks while conducting monitoring. PSOs 
would monitor all clearance and shutdown zones prior to, during, and 
following impact pile driving, vibratory pile driving, pneumatic 
hammering, UXO/MEC detonation, and during HRG surveys using boomers, 
sparkers, and CHIRPs (with monitoring durations specified further 
below). Any PSO would have the authority to call for a delay or 
shutdown of survey activities. PSOs will also monitor the Level B 
harassment zones and will document any marine mammals observed within 
these zones, to the extent practicable (noting that some zones are too 
large to fully observe). Observers would be located at the best 
practicable vantage points on the pile driving vessel and, where 
required, on an aerial platform. Full details regarding all marine 
mammal monitoring must be included in relevant Plans (e.g., Pile 
Driving and Marine Mammal Monitoring Plan) that, under this proposed 
action, Revolution Wind would be required to submit to NMFS for 
approval at least 180 days in advance of the commencement of any 
construction activities.
    The following measures apply to all visual monitoring efforts:
    1. Monitoring must be conducted by NMFS-approved, trained PSOs who 
would be placed at the primary location relevant to the activity (i.e., 
pile driving vessel, pneumatic hammering location, UXO/MEC vessel, HRG 
survey vessel), dedicated PSO vessels (e.g., additional UXO/MEC 
vessel(s) when the detonation area is larger than 2 km), and aerial 
survey plane and must be in positions that allow for the best vantage 
point to monitor for marine mammals and implement the relevant 
clearance and shutdown procedures, when determined to be applicable;
    2. PSO must be independent third-party observers and must have no 
tasks other than to conduct observational effort, collect data, and 
communicate with and instruct the relevant vessel crew with regard to 
the presence of protected species and mitigation requirements;
    3. During all observation periods related to pile driving (impact 
and vibratory), pneumatic hammering, UXO/MEC detonations, and HRG 
surveys, PSOs would be located at the best vantage point(s) in order to 
ensure 360[deg] visual coverage of the entire clearance and shutdown 
zones around the observing platform and as much of the Level B 
harassment zone as possible, while still maintaining a safe work 
environment;
    4. 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 single 24-hour period;
    5. PSOs would be required to use appropriate equipment (specified 
below) to monitor for marine mammals. During periods of low visibility 
(e.g., darkness, rain, fog, poor weather conditions, etc.), PSOs would 
be required to use alternative technologies (i.e., infrared or thermal 
cameras) to monitor the shutdown and clearance zones.
    6. PSOs should have the following minimum qualifications:
    a. Visual acuity in both eyes (corrected is permissible) sufficient 
for discernment of moving targets at the water's surface with the 
ability to estimate the target size and distance. The use of binoculars 
is permitted and may be necessary to correctly identify the target(s);

[[Page 79142]]

    b. Ability to conduct field observations and collect data according 
to the assigned protocols;
    c. Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
    d. Writing skills sufficient to document observations, including 
but not limited to: the number and species of marine mammals observed, 
the dates and times of when in-water construction activities were 
conducted, the dates and time 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.
    e. 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 Revolution Wind, in satisfaction of the 
mitigation and monitoring requirements described herein, must meet the 
following additional requirements:
    7. At least one observer must have prior experience working as an 
observer.
    8. Other observers may substitute education (a degree in biological 
science or a related field) or training for experience;
    9. One observer will be designated as lead observer or monitoring 
coordinator (``Lead PSO''). This Lead PSO would be required to have a 
minimum of 90 days of at-sea experience working in this role in an 
offshore environment, and would be required to have no more than 
eighteen months elapsed since the conclusion of their last at-sea 
experience;
    10. At least one PSO located on platforms (either vessel-based or 
aerial) would be required to have a minimum of 90 days of at-sea 
experience working in this role in an offshore environment and would be 
required to have no more than eighteen months elapsed since the 
conclusion of their last at-sea experience; and
    11. All PSOs must be approved by NMFS. Revolution Wind would be 
required to submit resumes of the initial set of PSOs necessary to 
commence the project to NMFS Office of Protected Resources (OPR) (at 
[email protected]) for approval at least 60 days prior to the first day 
of in-water construction activities requiring PSOs. Resumes would need 
to include the dates of training and any prior NMFS approval, as well 
as the dates and description of their last PSO experience, and must be 
accompanied by information documenting their successful completion of 
an acceptable training course. NMFS would allow three weeks to approve 
PSOs from the time that the necessary information is received by NMFS, 
after which any PSOs that meet the minimum requirements would 
automatically be considered approved.
    Some activities planned to be undertaken by Revolution Wind may 
require the use of PAM, which would necessitate the employment of at 
least one acoustic PSO (aka PAM operator) on duty at any given time. 
PAM operators would be required to meet several of the specified 
requirements described above for PSOs, including: 2, 4, 6b-e, 8, 9, 10, 
and 11. Furthermore, PAM operators would be required to complete a 
specialized training for operating PAM systems and must demonstrate 
familiarity with the PAM system on which they would be working.
    PSOs would be able to act as both acoustic and visual observers for 
the project if the individual(s) demonstrates that they have had the 
required level and appropriate training and experience to perform each 
task. However, a single individual would not be allowed to concurrently 
act in both roles or exceed work hours specified in #4 above.
    Revolution Wind's personnel and PSOs would also be required to use 
available sources of information on North Atlantic right whale presence 
to aid in monitoring efforts. This includes:
    1. Daily monitoring of the Right Whale Sightings Advisory System;
    2. Consulting of the WhaleAlert app; and,
    3. Monitoring of the Coast Guard's VHF Channel 16 throughout the 
day to receive notifications of any sightings and information 
associated with any Dynamic Management Areas, to plan construction 
activities and vessel routes, if practicable, to minimize the potential 
for co-occurrence with North Atlantic right whales.
    Additionally, whenever multiple project-associated vessels (of any 
size; e.g., construction survey, crew transfer) are operating 
concurrently, any visual observations of ESA-listed marine mammals must 
be communicated to PSOs and vessel captains associated with other 
vessels to increase situational awareness.
    The following are proposed monitoring and reporting measures that 
NMFS would require specific to each construction activity:

WTG and OSS Foundation Installation

    Revolution Wind would be required to implement the following 
monitoring procedures during all impact pile driving activities of 
monopiles related to WTG and OSS installation.
    During all observations associated with impact pile driving, PSOs 
would use high magnification (7x) binoculars and the naked eye to 
search continuously for marine mammals. At least one PSO on the 
foundation pile driving vessel and secondary dedicated-PSO vessel must 
be equipped with Big Eye binoculars (e.g., 25 x 50; 2,7 view angle; 
individual ocular focus; height control) of appropriate quality. These 
would be pedestal-mounted on the deck at the most appropriate vantage 
point that provides optimal sea surface observation and PSO safety.
    Revolution Wind would be required to have a minimum of four PSOs 
actively observing marine mammals before, during, and after (specific 
times described below) the installation of foundation piles 
(monopiles). At least two PSOs must be actively observing on the pile 
driving vessel while at least two PSOs are actively observing on a 
secondary, PSO-dedicated vessel. Concurrently, at least one acoustic 
PSO (i.e., passive acoustic monitoring (PAM) operator) must be actively 
monitoring for marine mammals before, during and after impact pile 
driving.
    As described in the Proposed Mitigation section, if the minimum 
visibility zone cannot be visually monitored at all times, pile driving 
operations may not commence or, if active, must shutdown, unless 
Revolution 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 creates risk of injury or loss of life for individuals.
    To supplement visual observation efforts, Revolution Wind would 
utilize at least one PAM operator before, during, and after pile 
installation. This PAM operator would assist the PSOs in ensuring full 
coverage of the clearance and shutdown zones. All on-duty visual PSOs 
would remain in contact with the on-duty PAM operator, who would 
monitor the PAM systems for acoustic detections of marine mammals in 
the area. In some cases, the PAM operator and workstation may be 
located onshore or they may be located on a vessel. In either 
situation, PAM operators would maintain constant and clear 
communication with visual PSOs on duty regarding detections of marine 
mammals that are approaching or within the applicable zones related to 
impact pile driving. Revolution Wind would utilize PAM to acoustically 
monitor the clearance and shutdown zones (and beyond for situational 
awareness), and would record all detections of marine mammals and 
estimated distance, when possible, to

[[Page 79143]]

the activity (noting whether they are in the Level A harassment or 
Level B harassment zones). To effectively utilize PAM, Revolution Wind 
would implement the following protocols:
     PAM operators would be stationed on at least one of the 
dedicated monitoring vessels in addition to the PSOs, or located 
remotely/onshore.
     PAM operators would have completed specialized training 
for operating PAM systems prior to the start of monitoring activities, 
including identification of species-specific mysticete vocalizations 
(e.g., North Atlantic right whales).
     The PAM operator(s) on-duty would monitor the PAM systems 
for acoustic detections of marine mammals that are vocalizing in the 
area.
     Any detections would be conveyed to the PSO team and any 
PSO sightings would be conveyed to the PAM operator for awareness 
purposes, and to identify if mitigation is to be triggered.
     For real-time PAM systems, at least one PAM operator would 
be designated to monitor each system by viewing data or data products 
that are streamed in real-time or near real-time to a computer 
workstation and monitor located on a project vessel or onshore.
     The PAM operator would inform the Lead PSO on duty of 
marine mammal detections approaching or within applicable ranges of 
interest to the pile driving activity via the data collection software 
system (i.e., Mysticetus or similar system), who would be responsible 
for requesting that the designated crewmember implement the necessary 
mitigation procedures (i.e., delay or shutdown).
     Acoustic monitoring during nighttime and low visibility 
conditions during the day would complement visual monitoring (e.g., 
PSOs and thermal cameras) and would cover an area of at least the Level 
B harassment zone around each foundation.
    All PSOs and PAM operators would be required to begin monitoring 60 
minutes prior to any impact pile driving, during, and after for 30 
minutes. However, PAM operators must review acoustic data from the 
previous 24 hours as well. As described in the Proposed Mitigation 
section, impact pile driving of monopiles would only commence when the 
minimum visibility zone (extending 2.3 km from the pile during summer 
months and 4.4 km during December for WTG foundation installations, and 
1.6 km during summer months and 2.7 km during December for OSS 
foundation installations) is fully visible (e.g., not obscured by 
darkness, rain, fog, etc.) and the clearance zones are clear of marine 
mammals for at least 30 minutes, as determined by the Lead PSO, 
immediately prior to the initiation of impact pile driving.
    For North Atlantic right whales, any visual (regardless of 
distance) or acoustic detection would trigger a delay to the 
commencement of pile driving. In the event that a large whale is 
sighted or acoustically detected that cannot be confirmed as a non-
North Atlantic right whale species, it must be treated as if it were a 
North Atlantic right whale. Following a shutdown, monopile installation 
may not recommence until the minimum visibility zone is fully visible 
and the clearance zone is clear of marine mammals for 30 minutes and no 
marine mammals have been detected acoustically within the PAM clearance 
zone for 30 minutes.
    Revolution Wind must prepare and submit a Pile Driving and Marine 
Mammal Monitoring Plan to NMFS for review and approval at least 180 
days before the start of any pile driving. The plans must include final 
pile driving project design (e.g., number and type of piles, hammer 
type, noise abatement systems, anticipated start date, etc.) and all 
information related to PAM PSO monitoring protocols for pile-driving 
and visual PSO protocols for all activities.

Cofferdam or Casing Pipe Installation and Removal

    Revolution Wind would be required to implement the following 
procedures during all vibratory pile driving activities associated with 
cofferdam installation and removal, and pneumatic hammering 
installation and removal of casing pipes.
    During all observation periods related to vibratory pile driving or 
pneumatic hammering, PSOs must use high-magnification (25x), standard 
handheld (7x) binoculars, and the naked eye to search continuously for 
marine mammals.
    Revolution Wind would be required to have a minimum of two PSOs on 
active duty during any installation and removal of the temporary 
cofferdams, or casing pipes and goal post sheet piles. These PSOs would 
always be located at the best vantage point(s) on the vibratory pile 
driving or pneumatic hammering platform or secondary platform in the 
immediate vicinity of the primary platforms, in order to ensure that 
appropriate visual coverage is available of the entire visual clearance 
zone and as much of the Level B harassment zone as possible. NMFS would 
not require the use of PAM for these activities.
    PSOs would monitor the clearance zone for the presence of marine 
mammals for 30 minutes before, throughout the installation of the sheet 
piles or casing pipes, and for 30 minutes after the activities have 
ceased. Sheet pile or casing pipe installation may only commence when 
visual clearance zones are fully visible (e.g., not obscured by 
darkness, rain, fog, etc.) and clear of marine mammals, as determined 
by the Lead PSO, for at least 30 minutes immediately prior to 
initiation of impact or vibratory pile driving.

UXO/MEC Detonations

    Revolution Wind would be required to implement the following 
procedures during all UXO/MEC detonations.
    During all observation periods related to UXO/MEC detonation, PSOs 
must use high-magnification (25x), standard handheld (7x) binoculars, 
and the naked eye to search continuously for marine mammals. PSOs 
located on the UXO/MEC monitoring vessel((s) would also be equipped 
with ``Big Eye'' binoculars (e.g., 25 x 150; 2.7 view angle; individual 
ocular focus; height control). These would be mounted on a pedestal on 
the deck of the vessel(s) at the most appropriate vantage to provide 
for optimal sea surface observation, as well as safety of the PSOs.
    For detonation zones (based on UXO/MEC charge weight) larger than 2 
km, a secondary vessel would be used for marine mammal monitoring. In 
the event a secondary vessel is needed, two PSOs would be located at an 
appropriate vantage point on this vessel and would maintain watch 
during the same time period as the PSOs on the primary monitoring 
vessel. For detonation zones larger than 5 km, Revolution Wind would 
also be required to perform an aerial survey. At least two PSOs must be 
deployed on the plane during the aerial survey that would occur before, 
during, and after UXO/detonation events. Revolution Wind would be 
required to ensure that the clearance zones are fully (100 percent) 
monitored prior to, during, and after detonations.
    As UXO/MEC detonation would only occur during daylight hours, PSOs 
would only need to monitor during the period between civil twilight 
rise and set. All PSOs and PAM operators would be required to begin 
monitoring 60 minutes prior to the UXO/MEC detonation event, during the 
event, and after for 30 minutes. Detonation may only commence when 
visual clearance zones are fully visible (e.g., not obscured by 
darkness, rain, fog, etc.) and clear of marine mammals, as determined 
by the Lead PSO, for at least

[[Page 79144]]

30 minutes immediately prior to detonation.
    The PAM operator(s) would be stationed on one of the dedicated 
monitoring vessels, but may also potentially be located remotely 
onshore, although the latter alternative is subject to approval by 
NMFS. When real-time PAM is used, at least one PAM operator would be 
designated to monitor each system by viewing the data or data products 
that would be streamed in real-time or near real-time to a computer 
workstation and monitor, which would be located either on an Revolution 
Wind vessel or onshore. The PAM operator would work in coordination 
with the visual PSOs to ensure the clearance zone is clear of marine 
mammals (both visually and acoustically) prior to the detonation. The 
PAM operator would inform the Lead PSO on-duty of any marine mammal 
detections approaching or within the clearance zones via the data 
collection software (i.e., Mysticetus or a similar system), who would 
then be responsible for requesting the necessary mitigation procedure 
(i.e., delay). The PAM operator would monitor the clearance zone for 
large whales, and beyond the zone as possible (dependent on the 
detection radius of the PAM monitoring equipment).
    Revolution Wind must prepare and submit a UXO/MEC and Marine Mammal 
Monitoring Plan to NMFS for review and approval at least 180 days 
before the start of any UXO/MEC. The plans must include final project 
design and all information related to visual and PAM PSO monitoring 
protocols for UXO/MEC detonations.

HRG Surveys

    Revolution Wind would be required to implement the following 
procedures during all HRG surveys.
    During all observation periods, PSOs must use standard handheld 
(7x) binoculars and the naked eye to search continuously for marine 
mammals.
    Between four and six PSOs would be present on every 24-hour survey 
vessel, and two to three PSOs would be present on every 12-hour survey 
vessel. Revolution Wind would be required to have at least one PSO on 
active duty during HRG surveys that are conducted during daylight hours 
(i.e., from 30 minutes prior to sunrise through 30 minutes following 
sunset) and at least two PSOs during HRG surveys that are conducted 
during nighttime hours.
    All PSOs would begin monitoring 30 minutes prior to the activation 
of boomers, sparkers, or CHIRPs; throughout use of these acoustic 
sources, and for 30 minutes after the use of the acoustic sources has 
ceased.
    Given that multiple HRG vessels may be operating concurrently, any 
observations of marine mammals would be required to be communicated to 
PSOs on all nearby survey vessels.
    Ramp-up of boomers, sparkers, and CHIRPs would only commence when 
visual clearance zones are fully visible (e.g., not obscured by 
darkness, rain, fog, etc.) and clear of marine mammals, as determined 
by the Lead PSO, for at least 30 minutes immediately prior to 
initiation of survey activities utilizing the specified acoustic 
sources.
    During daylight hours when survey equipment is not operating, 
Revolution Wind would ensure that visual PSOs conduct, as rotation 
schedules allow, observations for comparison of sighting rates and 
behavior with and without use of the specified acoustic sources. Off-
effort PSO monitoring must be reflected in the monthly PSO monitoring 
reports.

Marine Mammal Passive Acoustic Monitoring

    As described previously, Revolution Wind would be required to 
utilize a PAM system to supplement visual monitoring for all monopile 
installations, as well as during all UXO/MEC detonations. PAM operators 
may be on watch for a maximum of four consecutive hours followed by a 
break of at least two hours between watches. Again, PSOs can act as PAM 
operators or visual PSOs (but not simultaneously) as long as they 
demonstrate that their training and experience are sufficient to 
perform each task.
    The PAM system must be monitored by a minimum of one PAM operator 
beginning at least 60 minutes prior to soft start of impact pile 
driving of monopiles and UXO/MEC detonation, at all times during 
monopile installation and UXO/MEC detonation, and 30 minutes post-
completion of both activities. PAM operators must immediately 
communicate all detections of marine mammals at any distance (i.e., not 
limited to the Level B harassment zones) to visual PSOs, including any 
determination regarding species identification, distance, and bearing 
and the degree of confidence in the determination.
    PAM systems may be used for real-time mitigation monitoring. The 
requirement for real-time detection and localization limits the types 
of PAM technologies that can be used to those systems that are either 
cabled, satellite, or radio-linked. It is most likely that Revolution 
Wind would deploy autonomous or moored-remote PAM devices, including 
sonobuoy arrays or similar retrievable buoy systems. The system chosen 
will dictate the design and protocols of the PAM operations. Revolution 
Wind is not considering seafloor cabled PAM systems, in part due to 
high installation and maintenance costs, environmental issues related 
to cable laying, and the associated permitting complexities. For a 
review of the PAM systems Revolution Wind is considering, please see 
Appendix 4 of the Protected Species Mitigation and Monitoring Plan 
included in Revolution Wind's ITA application.
    Towed PAM systems may be utilized for the Revolution Wind project 
only if additional PAM systems are necessary. Towed systems consist of 
cabled hydrophone arrays that would be deployed from a vessel and then 
typically monitored from the tow vessel. Notably, several challenges 
exist when using a towed PAM system (i.e., the tow vessel may not be 
fit for the purpose as it may be towing other equipment, operating 
sound sources, or working in patterns not conducive to effective PAM). 
Furthermore, detection and localization capabilities for low-frequency 
cetacean calls (i.e., mysticete species) can be difficult in a 
commercial deployment setting. Alternatively, these systems have many 
advantages, as they are often low cost to operate, have high mobility, 
and are fairly easy and reliable to operate. These types of systems 
also work well in conjunction with visual monitoring efforts.
    Revolution Wind plans to deploy PAM arrays specific for mitigation 
and monitoring of marine mammals outside of the shutdown zone to 
optimize the PAM system's capabilities to monitor for the presence of 
animals potentially entering these zones. The exact configuration and 
number of PAM devices would depend on the size of the zone(s) being 
monitored, the amount of noise expected in the area, and the 
characteristics of the signals being monitored. More closely spaced 
hydrophones would allow for more directionality and, perhaps, range to 
the vocalizing marine mammals; however, this approach would add 
additional costs and greater levels of complexity to the project. 
Mysticetes, which would produce relatively loud and lower-frequency 
vocalizations, may be able to be heard with fewer hydrophones spaced at 
greater distances. However, detecting smaller cetaceans (such as mid-
frequency delphinids; odontocetes) may necessitate that more 
hydrophones be spaced closer together given the shorter propagation 
range of the shorter, mid-frequency acoustic signals (e.g., whistles 
and echolocation clicks). As there are no ``perfect fit'' single 
optimal array configurations, these set-ups

[[Page 79145]]

would need to be considered on a case-by-case basis.
    A Passive Acoustic Monitoring (PAM) Plan must be submitted to NMFS 
for review and approval at least 180 days prior to the planned start of 
monopile installations. PAM should follow standardized measurement, 
processing methods, reporting metrics, and metadata standards for 
offshore wind (Van Parijs et al., 2021). The plan must describe all 
proposed PAM equipment, procedures, and protocols. However, NMFS 
considers PAM usage for every project on a case-by-case basis, and 
would continue discussions with Revolution Wind regarding selection of 
the PAM system that is most appropriate for the proposed project. The 
authorization to take marine mammals would be contingent upon NMFS' 
approval of the PAM Plan.

Acoustic Monitoring for Sound Field and Harassment Isopleth 
Verification (SFV)

    During the installation of the first three monopile foundations, 
and during all UXO/MEC detonations, Revolution Wind must empirically 
determine source levels, the ranges to the isopleths corresponding to 
the Level A harassment and Level B harassment thresholds, and the 
transmission loss coefficient(s). Revolution Wind may also estimate 
ranges to the Level A harassment and Level B harassment isopleths by 
extrapolating from in situ measurements conducted at several distances 
from the monopile being driven, and UXO/MEC being detonated. Revolution 
Wind must measure received levels at a standard distance of 750 m from 
the monopiles and at both the presumed modeled Level A harassment and 
Level B harassment isopleth ranges, or an alternative distance(s) as 
agreed to in the SFV Plan.
    If acoustic field measurements collected during for installation of 
the first or subsequent monopile, and UXOs/MEC being detonated, 
indicate ranges to the isopleths corresponding to Level A harassment 
and Level B harassment thresholds are greater than the ranges predicted 
by modeling (assuming 10-dB attenuation), Revolution Wind must 
implement additional noise mitigation measures prior to installing the 
next monopile, or detonating any additional UXOs/MECs. Initial 
additional measures may include improving the efficacy of the 
implemented noise mitigation technology (e.g., BBC, DBBC) and/or 
modifying the piling schedule to reduce the sound source. Each 
sequential modification would be evaluated empirically by acoustic 
field measurements. In the event that field measurements indicate 
ranges to isopleths corresponding to Level A harassment and Level B 
harassment thresholds are greater than the ranges predicted by modeling 
(assuming 10-dB attenuation), NMFS may expand the relevant harassment, 
clearance, and shutdown zones and associated monitoring protocols. If 
harassment zones are expanded beyond an additional 1,500 m, additional 
PSOs would be deployed on additional platforms, with each observer 
responsible for maintaining watch in no more than 180[deg] and of an 
area with a radius no greater than 1,500 m.
    If acoustic measurements indicate that ranges to isopleths 
corresponding to the Level A harassment and Level B harassment 
thresholds are less than the ranges predicted by modeling (assuming 10-
dB attenuation), Revolution Wind may request a modification of the 
clearance and shutdown zones for impact pile driving of monopiles and 
for detonation of UXOs/MECs. For a modification request to be 
considered by NMFS, Revolution Wind would have had to conduct SFV on 
three or more monopiles and on all detonated UXOs/MECs thus far to 
verify that zone sizes are consistently smaller than those predicted by 
modeling (assuming 10-dB attenuation). In addition, if a subsequent 
monopile installation location is selected that was not represented by 
previous three locations (i.e., substrate composition, water depth), 
SFV would be required. Furthermore, if a subsequent UXO/MEC charge 
weight is encountered and/or detonation location is selected that was 
not representative of the previous locations (i.e., substrate 
composition, water depth), SFV would also be required. Upon receipt of 
an interim SFV report, NMFS may adjust zones (i.e., Level A harassment, 
Level B harassment, clearance, shutdown, and/or minimum visibility 
zone) to reflect SFV measurements. The shutdown and clearance zones for 
pile driving would be equivalent to the measured range to the Level A 
harassment isopleths plus 10 percent (shutdown zone) and 20 percent 
(clearance zone), rounded up to the nearest 100 m for PSO clarity. The 
minimum visibility zone would be based on the largest measured distance 
to the Level A harassment isopleth for large whales. Regardless of SFV, 
a North Atlantic right whale detected at any distance by PSOs would 
continue to result in a delay to the start of pile driving. Similarly, 
if pile driving has commenced, shutdown would be called for in the 
event a right whale is observed at any distance. That is, the visual 
clearance and shutdown criteria for North Atlantic right whales would 
not change, regardless of field acoustic measurements. The Level B 
harassment zone would be equal to the largest measured range to the 
Level B harassment isopleth.
    The SFV plan must also include how operational noise would be 
monitored. Revolution Wind would be required to estimate source levels 
(at 10 m from the operating foundation) based on received levels 
measured at 50 m, 100 m, and 250 m from the pile foundation. These data 
must be used to identify estimated transmission loss rates. Operational 
parameters (e.g., direct drive/gearbox information, turbine rotation 
rate) as well as sea state conditions and information on nearby 
anthropogenic activities (e.g., vessels transiting or operating in the 
area) must be reported.
    Revolution Wind must submit a SFV Plan at least 180 days prior to 
the planned start of impact pile driving and any UXO/MEC detonation 
activities. The plan must describe how Revolution Wind would ensure 
that the first three monopile foundation installation sites selected 
and each UXO/MEC detonation scenario (i.e., charge weight, location) 
selected for SFV are representative of the rest of the monopile 
installation sites and UXO/MEC scenarios. Revolution Wind must include 
information on how additional sites/scenarios would be selected for SFV 
should it be determined that these sites/scenarios are not 
representative of all other monopile installation sites and UXO/MEC 
detonations. The plan must also include the methodology for collecting, 
analyzing, and preparing SFV data for submission to NMFS. The plan must 
describe how the effectiveness of the sound attenuation methodology 
would be evaluated based on the results. Revolution Wind must also 
provide, as soon as they are available but no later than 48 hours after 
each installation, the initial results of the SFV measurements to NMFS 
in an interim report after each monopile for the first three piles and 
after each UXO/MEC detonation.

Reporting

    Prior to any construction activities occurring, Revolution Wind 
would provide a report to NMFS (at [email protected] and 
[email protected]) documenting that all required 
training for Revolution Wind personnel (i.e., vessel crews, vessel 
captains, PSOs, and PAM operators) has been completed.
    NMFS would require standardized and frequent reporting from 
Revolution Wind during the life of the proposed

[[Page 79146]]

regulations and LOA. All data collected relating to the Revolution Wind 
project would be recorded using industry-standard software (e.g., 
Mysticetus or a similar software) installed on field laptops and/or 
tablets. Revolution Wind would be required to submit weekly, monthly 
and annual reports as described below. During activities requiring 
PSOs, the following information would be collected and reported related 
to the activity being conducted:
     Date and time that monitored activity begins or ends;
     Construction activities occurring during each observation 
period;
     Watch status (i.e., sighting made by PSO on/off effort, 
opportunistic, crew, alternate vessel/platform);
     PSO who sighted the animal;
     Time of sighting;
     Weather parameters (e.g., wind speed, percent cloud cover, 
visibility);
     Water conditions (e.g., sea state, tide state, water 
depth);
     All marine mammal sightings, regardless of distance from 
the construction activity;
     Species (or lowest possible taxonomic level possible)
     Pace of the animal(s);
     Estimated number of animals (minimum/maximum/high/low/
best);
     Estimated number of animals by cohort (e.g., adults, 
yearlings, juveniles, calves, group composition, etc.);
     Description (i.e., as many distinguishing features as 
possible of each individual seen, including length, shape, color, 
pattern, scars or markings, shape and size of dorsal fin, shape of 
head, and blow characteristics);
     Description of any marine mammal behavioral observations 
(e.g., observed behaviors such as feeding or traveling) and observed 
changes in behavior, including an assessment of behavioral responses 
thought to have resulted from the specific activity;
     Animal's closest distance and bearing from the pile being 
driven, UXO/MEC, or specified HRG equipment and estimated time entered 
or spent within the Level A harassment and/or Level B harassment zones;
     Construction activity at time of sighting (e.g., vibratory 
installation/removal, impact pile driving, UXO/MEC detonation, HRG 
survey), use of any noise abatement device(s), and specific phase of 
activity (e.g., ramp-up of HRG equipment, HRG acoustic source on/off, 
soft start for pile driving, active pile driving, post-UXO/MEC 
detonation, etc.);
     Description of any mitigation-related action implemented, 
or mitigation-related actions called for but not implemented, in 
response to the sighting (e.g., delay, shutdown, etc.) and time and 
location of the action; and
     Other human activity in the area.
    For all real-time acoustic detections of marine mammals, the 
following must be recorded and included in weekly, monthly, annual, and 
final reports:
    a. Location of hydrophone (latitude & longitude; in Decimal 
Degrees) and site name;
    b. Bottom depth and depth of recording unit (in meters);
    c. Recorder (model & manufacturer) and platform type (i.e., bottom-
mounted, electric glider, etc.), and instrument ID of the hydrophone 
and recording platform (if applicable);
    d. Time zone for sound files and recorded date/times in data and 
metadata (in relation to UTC. i.e., EST time zone is UTC-5);
    e. Duration of recordings (start/end dates and times; in ISO 8601 
format, yyyy-mm-ddTHH:MM:SS.sssZ);
    f. Deployment/retrieval dates and times (in ISO 8601 format);
    g. Recording schedule (must be continuous);
    h. Hydrophone and recorder sensitivity (in dB re. 1 [mu]Pa);
    i. Calibration curve for each recorder;
    j. Bandwidth/sampling rate (in Hz);
    k. Sample bit-rate of recordings; and
    l. Detection range of equipment for relevant frequency bands (in 
meters).
    For each detection the following information must be noted:
    a. Species identification (if possible);
    b. Call type and number of calls (if known);
    c. Temporal aspects of vocalization (date, time, duration, etc., 
date times in ISO 8601 format);
    d. Confidence of detection (detected, or possibly detected);
    e. Comparison with any concurrent visual sightings;
    f. Location and/or directionality of call (if determined) relative 
to acoustic recorder or construction activities;
    g. Location of recorder and construction activities at time of 
call;
    h. Name and version of detection or sound analysis software used, 
with protocol reference;
    i. Minimum and maximum frequencies viewed/monitored/used in 
detection (in Hz); and
    j. Name of PAM operator(s) on duty.
    If a North Atlantic right whale is detected via Revolution Wind 
PAM, the date, time, location (i.e., latitude and longitude of 
recorder) of the detection as well as the recording platform that had 
the detection must be reported to [email protected] as soon as 
feasible, but no longer than 24 hours after the detection. Full 
detection data and metadata must be submitted monthly on the 15th of 
every month for the previous month via the webform on the NMFS North 
Atlantic right whale Passive Acoustic Reporting System website (https://www.fisheries.noaa.gov/resource/document/passive-acoustic-reporting-system-templates).
    If a North Atlantic right whale is observed at any time by PSOs or 
personnel on or in the vicinity of any impact or vibratory pile-driving 
vessel, dedicated PSO vessel, construction survey vessel, during vessel 
transit, or during an aerial survey, Revolution Wind must immediately 
report sighting information to the NMFS North Atlantic Right Whale 
Sighting Advisory System (866) 755-6622, to the U.S. Coast Guard via 
channel 16, and through the WhaleAlert app (https://www.whalealert.org/
) as soon as feasible but no longer than 24 hours after the sighting. 
Information reported must include, at a minimum: time of sighting, 
location, and number of North Atlantic right whales observed.
    SFV Interim Report--Revolution Wind would be required to provide, 
as soon as they are available but no later than 48 hours after each 
installation, the initial results of SFV measurements to NMFS in an 
interim report after each monopile for the first three piles and any 
subsequent piles monitored. An SFV interim report must also be 
submitted within 48 hours after each UXO/MEC detonation.
    Weekly Report--Revolution Wind would be required to compile and 
submit weekly PSO, PAM, and SFV reports to NMFS (at [email protected] 
and [email protected]) that document the daily start 
and stop of all pile driving, pneumatic hammering, HRG survey, or UXO/
MEC detonation activities, the start and stop of associated observation 
periods by PSOs, details on the deployment of PSOs, a record of all 
detections of marine mammals (acoustic and visual), any mitigation 
actions (or if mitigation actions could not be taken, provide reasons 
why), and details on the noise abatement system(s) used and its 
performance. Weekly reports would be due on Wednesday for the previous 
week (Sunday-Saturday). The weekly report would also identify which 
turbines become operational and when (a map must be provided). Once all 
foundation pile installation is complete, weekly reports would no 
longer be required.
    Monthly Report--Revolution Wind would be required to compile and 
submit monthly reports to NMFS (at [email protected] and

[[Page 79147]]

[email protected]) that include a summary of all 
information in the weekly reports, including project activities carried 
out in the previous month, vessel transits (number, type of vessel, and 
route), number of piles installed, number of UXO/MEC detonations, all 
detections of marine mammals, and any mitigative actions taken. Monthly 
reports would be due on the 15th of the month for the previous month. 
The monthly report would also identify which turbines become 
operational and when (a map must be provided). Once foundation pile 
installation is complete, monthly reports would no longer be required.
    Annual Report--Revolution Wind would be required to submit an 
annual PSO PAM, and SFV summary report to NMFS (at [email protected] 
and [email protected]) no later than 90 days following 
the end of a given calendar year describing, in detail, all of the 
information required in the monitoring section above. A final annual 
report would be prepared and submitted within 30 calendar days 
following receipt of any NMFS comments on the draft report. If no 
comments were received from NMFS within 60 calendar days of NMFS' 
receipt of the draft report, the report would be considered final.
    Final Report--Revolution Wind must submit its draft final report(s) 
to NMFS (at [email protected] and [email protected]) on 
all visual and acoustic monitoring conducted under the LOA within 90 
calendar days of the completion of activities occurring under the LOA. 
A final report must be prepared and submitted within 30 calendar days 
following receipt of any NMFS comments on the draft report. If no 
comments are received from NMFS within 30 calendar days of NMFS' 
receipt of the draft report, the report shall be considered final.
Situational Reporting
    Specific situations encountered during the development of the 
Revolution Wind project would require reporting. These situations and 
the relevant procedures include:
     If a marine mammal observation occurs during vessel 
transit, the following information must be recorded and reported:
    a. Time, date, and location;
    b. The vessel's activity, heading, and speed;
    c. Sea state, water depth, and visibility;
    d. Marine mammal identification to the best of the observer's 
ability (e.g., North Atlantic right whale, whale, dolphin, seal);
    e. Initial distance and bearing to marine mammal from vessel and 
closest point of approach; and,
    f. Any avoidance measures taken in response to the marine mammal 
sighting.
     If a sighting of a stranded, entangled, injured, or dead 
marine mammal occurs, the sighting would be reported to NMFS OPR, the 
NMFS Greater Atlantic Regional Fisheries Office (GARFO) Marine Mammal 
and Sea Turtle Stranding & Entanglement Hotline (866-755-6622), and the 
U.S. Coast Guard within 24 hours. If the injury or death was caused by 
a project activity, Revolution Wind must immediately cease all 
activities until NMFS OPR is able to review the circumstances of the 
incident and determine what, if any, additional measures are 
appropriate to ensure compliance with the terms of the LOA. NMFS may 
impose additional measures to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. Revolution Wind may not 
resume their activities until notified by NMFS. The report must include 
the following information:
    g. Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
    h. Species identification (if known) or description of the 
animal(s) involved;
    i. Condition of the animal(s) (including carcass condition if the 
animal is dead);
    j. Observed behaviors of the animal(s), if alive;
    k. If available, photographs or video footage of the animal(s); and
    l. General circumstances under which the animal was discovered.
     In the event of a vessel strike of a marine mammal by any 
vessel associated with the Revolution Wind project, Revolution Wind 
shall immediately report the strike incident to the NMFS OPR and the 
GARFO within and no later than 24 hours. Revolution Wind must 
immediately cease all activities until NMFS OPR is able to review the 
circumstances of the incident and determine what, if any, additional 
measures are appropriate to ensure compliance with the terms of the 
LOA. NMFS may impose additional measures to minimize the likelihood of 
further prohibited take and ensure MMPA compliance. Revolution Wind may 
not resume their activities until notified by NMFS. The report must 
include the following information:
    a. Time, date, and location (latitude/longitude) of the incident;
    b. Species identification (if known) or description of the 
animal(s) involved;
    c. Vessel's speed during and leading up to the incident;
    d. Vessel's course/heading and what operations were being conducted 
(if applicable);
    e. Status of all sound sources in use;
    f. Description of avoidance measures/requirements that were in 
place at the time of the strike and what additional measures were 
taken, if any, to avoid strike;
    g. Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, visibility) immediately preceding the 
strike;
    h. Estimated size and length of animal that was struck;
    i. Description of the behavior of the marine mammal immediately 
preceding and following the strike;
    j. If available, description of the presence and behavior of any 
other marine mammals immediately preceding the strike;
    k. Estimated fate of the animal (e.g., dead, injured but alive, 
injured and moving, blood or tissue observed in the water, status 
unknown, disappeared); and
    l. To the extent practicable, photographs or video footage of the 
animal(s).
Sound Monitoring Reporting
    As described previously, Revolution Wind would be required to 
provide the initial results of SFV (including measurements) to NMFS in 
interim reports after each monopile installation for the first three 
piles (and any subsequent piles) as soon as they are available, but no 
later than 48 hours after each installation. Revolution Wind would also 
have to provide interim reports after every UXO/MEC detonation as soon 
as they are available, but no later than 48 hours after each 
detonation. In addition to in situ measured ranges to the Level A 
harassment and Level B harassment isopleths, the acoustic monitoring 
report must include: hammer energies (pile driving), UXO/MEC weight 
(including donor charge weight), SPLpeak, SPLrms 
that contains 90 percent of the acoustic energy, single strike sound 
exposure level, integration time for SPLrms, and 24-hour 
cumulative SEL extrapolated from measurements. The sound levels 
reported must be in median and linear average (i.e., average in linear 
space), and in dB. All these levels must be reported in the form of 
median, mean, max, and minimum. The SEL and SPL power spectral density 
and one-third octave band levels (usually calculated as decidecade band 
levels) at the receiver

[[Page 79148]]

locations should be reported. The acoustic monitoring report must also 
include: a description of the SFV PAM hardware and software, including 
software version used, calibration data, bandwidth capability and 
sensitivity of hydrophone(s), any filters used in hardware or software, 
any limitations with the equipment, a description of the hydrophones 
used, hydrophone and water depth, distance to the pile driven, sediment 
type at the recording location, and local environmental conditions 
(e.g., wind speed). In addition, pre- and post-activity ambient sound 
levels (broadband and/or within frequencies of concern) should be 
reported. Finally, the report must include a description of the noise 
abatement system and operational parameters (e.g., bubble flow rate, 
distance deployed from the pile or UXO/MEC location, etc.), and any 
action taken to adjust the noise abatement system. Final results of SFV 
must be submitted as soon as possible, but no later than within 90 days 
following completion of impact pile driving of monopiles and UXOs/MECs 
detonations.

Adaptive Management

    The regulations governing the take of marine mammals incidental to 
Revolution Wind's construction activities would contain an adaptive 
management component. The reporting requirements associated with this 
rule are designed to provide NMFS with monitoring data throughout the 
life of the project that can inform potential from completed projects 
to allow consideration of whether any changes to mitigation or 
monitoring are appropriate. The use of adaptive management allows NMFS 
to consider new information from different sources to determine (with 
input from Revolution Wind regarding practicability) on an annual or 
biennial basis if mitigation or monitoring measures should be modified 
(including additions or deletions). Mitigation measures could be 
modified if new data suggests that such modifications would have a 
reasonable likelihood of reducing adverse effects to marine mammals and 
if the measures are practicable.
    The following are some of the possible sources of applicable data 
to be considered through the adaptive management process: (1) Results 
from monitoring reports, as required by MMPA authorizations; (2) 
results from general marine mammal and sound research; and (3) any 
information which reveals that marine mammals may have been taken in a 
manner, extent, or number not authorized by these regulations or 
subsequent LOA. During the course of the rule, Revolution Wind (and 
other LOA-holders conducting offshore wind development activities) 
would be required to participate in one or more adaptive management 
meetings convened by NMFS and/or BOEM, in which the above information 
would be summarized and discussed in the context of potential changes 
to the mitigation or monitoring measures.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' by mortality, serious injury, and Level A harassment or Level 
B harassment, we consider other factors, such as the likely nature of 
any behavioral responses (e.g., intensity, duration), the context of 
any such responses (e.g., critical reproductive time or location, 
migration), as well as effects on habitat, and the likely effectiveness 
of mitigation. We also assess the number, intensity, and context of 
estimated takes by evaluating this information relative to population 
status. Consistent with the 1989 preamble for NMFS' 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).
    In the Estimated Take section, we identified the subset of 
potential effects that would be expected to qualify as takes under the 
MMPA, and then identified the maximum number of takes by Level A 
harassment and Level B harassment that we estimate are reasonably 
expected to occur based on the methods described. The impact that any 
given take would have is dependent on many case-specific factors that 
need to be considered in the negligible impact analysis (e.g., the 
context of behavioral exposures such as duration or intensity of a 
disturbance, the health of impacted animals, the status of a species 
that incurs fitness-level impacts to individuals, etc.). In this rule, 
we evaluate the likely impacts of the enumerated harassment takes that 
are proposed for authorization in the context of the specific 
circumstances surrounding these predicted takes. We also collectively 
evaluate this information, as well as other more taxa-specific 
information and mitigation measure effectiveness, in group-specific 
discussions that support our negligible impact conclusions for each 
stock. As also described above, no serious injury or mortality is 
expected or proposed for authorization for any species or stock.
    The Description of the Specified Activities section describes the 
specified activities proposed by Revolution Wind that may result in 
take of marine mammals and an estimated schedule for conducting those 
activities. Revolution Wind has provided a realistic construction 
schedule (e.g., Revolution Wind's schedule reflects the maximum number 
of piles they anticipate to be able to drive each month in which pile 
driving is authorized to occur), although we recognize schedules may 
shift for a variety of reasons (e.g., weather or supply delays). 
However, the total amount of take would not exceed the 5 year totals 
and maximum annual total in any given year indicated in Tables 33 and 
34, respectively.
    We base our analysis and negligible impact determination (NID) on 
the maximum number of takes that would be reasonably expected to occur 
and are proposed to be authorized in the 5-year LOA, if issued, and 
extensive qualitative consideration of other contextual factors that 
influence the degree of impact of the takes on the affected individuals 
and the number and context of the individuals affected. As stated 
before, the number of takes, both annual and 5-year total, alone are 
only a part of the analysis. To avoid repetition, we provide some 
general analysis in this Negligible Impact Analysis and Determination 
section that applies to all the species listed in Table 4, given that 
some of the anticipated effects of Revolution Wind's construction 
activities on marine mammals are expected to be relatively similar in 
nature. Then, we subdivide into more detailed discussions for 
mysticetes, odontocetes, and pinnipeds which have broad life history 
traits that support an overarching discussion of some factors 
considered within the analysis for those groups (e.g., habitat-use 
patterns, high-level differences in feeding strategies).
    Last, we provide a negligible impact determination for each species 
or stock,

[[Page 79149]]

providing species or stock-specific information or analysis, where 
appropriate, for example, for North Atlantic right whales given their 
population status. Organizing our analysis by grouping species or 
stocks that share common traits or that would respond similarly to 
effects of Revolution Wind's proposed activities, and then providing 
species- or stock-specific information allows us to avoid duplication 
while ensuring that we have analyzed the effects of the specified 
activities on each affected species or stock. It is important to note 
that in the group or species sections, we base our negligible impact 
analysis on the maximum annual take that is predicted under the 5-year 
rule; however, the majority of the impacts are associated with WTG and 
OSS foundation installation, which would occur largely within a 1-year 
period. The estimated take in the other years is expected to be notably 
less, which is reflected in the total take that would be allowable 
under the rule (see Tables 32, 33, and 34).
    As described previously, no serious injury or mortality is 
anticipated or proposed for authorization in this rule. The amount of 
harassment Revolution Wind has requested, and NMFS is proposing to 
authorize, is based on exposure models that consider the outputs of 
acoustic source and propagation models. Several conservative parameters 
and assumptions are ingrained into these models, such as assuming 
forcing functions that consider direct contact with piles (i.e., no 
cushion allowances) and application of the highest monthly sound speed 
profile to all months within a given season. In addition, the exposure 
model results do not reflect any mitigation measures (except for North 
Atlantic right whales) or avoidance response, and some of those results 
have been adjusted upward to consider sighting or group size data, 
where necessary. The resulting values for each stock were then used by 
Revolution Wind to request take by behavioral harassment. The only case 
in which mitigation measures (other than source level reduction via a 
noise abatement system) were considered is the potential for PTS (Level 
A harassment) of large whales. Models used to predict exposures for 
impact pile driving and UXO/MEC detonations predicted PTS exposures for 
multiple species. However, Revolution Wind did not request, and we are 
not proposing to authorize, Level A harassment of any baleen whale 
species other than humpback whales due, in large part, to the extended 
mitigation measures for large whales. Therefore, for all species, the 
amount of take proposed to be authorized represents the maximum amount 
of Level A harassment and Level B harassment that is reasonably 
expected to occur.
Behavioral Disturbance
    In general, NMFS anticipates that impacts on an individual that has 
been harassed are likely to be more intense when exposed to higher 
received levels and for a longer duration (though this is in no way a 
strictly linear relationship for behavioral effects across species, 
individuals, or circumstances) and less severe impacts result when 
exposed to lower received levels and for a brief duration. However, 
there is also growing evidence of the importance of contextual factors 
such as distance from a source in predicting marine mammal behavioral 
response to sound--i.e., sounds of a similar level emanating from a 
more distant source have been shown to be less likely to evoke a 
response of equal magnitude (e.g., DeRuiter, 2012, Falcone et al., 
2017). As described in the Potential Effects to Marine Mammals and 
their Habitat section, the intensity and duration of any impact 
resulting from exposure to Revolution Wind's activities is dependent 
upon a number of contextual factors including, but not limited to, 
sound source frequencies, whether the sound source is moving towards 
the animal, hearing ranges of marine mammals, behavioral state at time 
of exposure, status of individual exposed (e.g., reproductive status, 
age class, health) and an individual's experience with similar sound 
sources. Ellison et al. (2012) and Moore and Barlow (2013), among 
others, emphasize the importance of context (e.g., behavioral state of 
the animals, distance from the sound source) in evaluating behavioral 
responses of marine mammals to acoustic sources. Harassment of marine 
mammals may result in behavioral modifications (e.g., avoidance, 
temporary cessation of foraging or communicating, changes in 
respiration or group dynamics, masking) or may result in auditory 
impacts such as hearing loss. In addition, some of the lower level 
physiological stress responses (e.g., orientation or startle response, 
change in respiration, change in heart rate) discussed previously would 
likely co-occur with the behavioral modifications, although these 
physiological responses are more difficult to detect and fewer data 
exist relating these responses to specific received levels of sound. 
Takes by Level B harassment, then, may have a stress-related 
physiological component as well; however, we would not expect 
Revolution Wind's activities to produce conditions of long-term and 
continuous exposure to noise leading to long-term physiological stress 
responses in marine mammals that could affect reproduction or survival.
    In the range of potential behavioral effects that might be expected 
to be part of a response that qualifies as an instance of Level B 
harassment by behavioral disturbance (which by nature of the way it is 
modeled/counted, occurs within one day), the less severe end might 
include exposure to comparatively lower levels of a sound, at a greater 
distance from the animal, for a few or several minutes. A less severe 
exposure of this nature could result in a behavioral response such as 
avoiding an area that an animal would otherwise have chosen to move 
through or feed in for some amount of time, or breaking off one or a 
few feeding bouts. More severe effects could occur if an animal gets 
close enough to the source to receive a comparatively higher level, is 
exposed continuously to one source for a longer time, or is exposed 
intermittently to different sources throughout a day. Such effects 
might result in an animal having a more severe flight response, and 
leaving a larger area for a day or more or potentially losing feeding 
opportunities for a day. However, such severe behavioral effects are 
expected to occur infrequently.
    Many species perform vital functions, such as feeding, resting, 
traveling, and socializing on a diel cycle (24-hour cycle). Behavioral 
reactions to noise exposure, when taking place in a biologically 
important context, such as disruption of critical life functions, 
displacement, or avoidance of important habitat, are more likely to be 
significant if they last more than one day or recur on subsequent days 
(Southall et al., 2007) due to diel and lunar patterns in diving and 
foraging behaviors observed in many cetaceans (Baird et al., 2008, 
Barlow et al., 2020, Henderson et al., 2016, Schorr et al., 2014). It 
is important to note the water depth in the Revolution Wind project 
area is shallow (5 to 50 m) and deep diving species, such as sperm 
whales, are not expected to be engaging in deep foraging dives when 
exposed to noise above NMFS harassment thresholds during the specified 
activities. Therefore, we do not anticipate impacts to deep foraging 
behavior to be impacted by the specified activities.
    It is also important to identify that the estimated number of takes 
does not necessarily equate to the number of individual animals 
Revolution Wind expects to harass (which is lower), but

[[Page 79150]]

rather to the instances of take (i.e., exposures above the Level B 
harassment thresholds) that are anticipated to occur. These instances 
may represent either brief exposures (e.g., seconds for UXO/MEC 
detonation, or seconds to minutes for HRG surveys) or, in some cases, 
longer durations of exposure within a day (e.g., pile driving). Some 
individuals of a species may experience recurring instances of take 
over multiple days throughout the year, while some members of a species 
or stock may experience one exposure as they move through an area or 
not experience take at all, which means that the number of individuals 
taken is smaller than the total estimated takes. In short, for species 
that are more likely to be migrating through the area and/or for which 
only a comparatively smaller number of takes are predicted (e.g., some 
of the mysticetes), it is more likely that each take represents a 
different individual, whereas for non-migrating species with larger 
amounts of predicted take, we expect that the total anticipated takes 
represent exposures of a smaller number of individuals of which some 
would be exposed multiple times.
    For the Revolution Wind project, impact pile driving is most likely 
to result in a higher magnitude and severity of behavioral disturbance 
than other activities (i.e., vibratory pile driving, UXO/MEC 
detonation, and HRG surveys). Impact pile driving has higher source 
levels than vibratory pile driving and HRG sources. HRG survey 
equipment also produces much higher frequencies than pile driving, 
resulting in minimal sound propagation. While UXO/MEC detonations may 
have higher source levels, impact pile driving is planned for longer 
durations (i.e., a maximum of 13 UXO/MEC detonations are planned, which 
would result in only instantaneous exposures). While impact pile 
driving is anticipated to be most impactful for these reasons, impacts 
are minimized through implementation of mitigation measures, including 
soft-start, use of a sound attenuation system, and the implementation 
of clearance zones that would facilitate a delay of pile driving if 
marine mammals were observed approaching or within areas that could be 
ensonified above sound levels that could result in Level B harassment. 
Given sufficient notice through the use of soft-start, marine mammals 
are expected to move away from a sound source that is annoying prior to 
becoming exposed to very loud noise levels. The requirement that pile 
driving can only commence when the full extent of all clearance zones 
are fully visible to visual PSOs would ensure a higher marine mammal 
detection, enabling a high rate of success in implementation of 
clearance zones. Furthermore, Revolution Wind would be required to 
utilize PAM prior to and during all clearance periods, during impact 
pile driving, and after pile driving has ended during the post-piling 
period. PAM has been shown to be particularly effective when used in 
conjunction with visual observations, increasing the overall capability 
to detect marine mammals (Van Parijs et al., 2021). These measures also 
apply to UXO/MEC detonation(s), which also have the potential to elicit 
more severe behavioral reactions in the unlikely event that an animal 
is relatively close to the explosion in the instant that it occurs; 
hence, severity of behavioral responses are expected to be lower than 
would be the case without mitigation.
    Occasional, milder behavioral reactions are unlikely to cause long-
term consequences for individual animals or populations, and even if 
some smaller subset of the takes are in the form of a longer (several 
hours or a day) and more severe response, if they are not expected to 
be repeated over sequential days, impacts to individual fitness are not 
anticipated. Nearly all studies and experts agree that infrequent 
exposures of a single day or less are unlikely to impact an 
individual's overall energy budget (Farmer et al., 2018; Harris et al., 
2017; King et al., 2015; NAS 2017; New et al., 2014; Southall et al., 
2007; Villegas-Amtmann et al., 2015).

Temporary Threshold Shift (TTS)

    TTS is one form of Level B harassment that marine mammals may incur 
through exposure to Revolution Wind's activities and, as described 
earlier, the proposed takes by Level B harassment may represent takes 
in the form of behavioral disturbance, TTS, or both. As discussed in 
the Potential Effects to Marine Mammals and their Habitat section, in 
general, TTS can last from a few minutes to days, be of varying degree, 
and occur across different frequency bandwidths, all of which determine 
the severity of the impacts on the affected individual, which can range 
from minor to more severe. Impact and vibratory pile driving generate 
sounds in the lower frequency ranges (with most of the energy below 1-2 
kHz, but with a small amount energy ranging up to 20 kHz); therefore, 
in general and all else being equal, we would anticipate the potential 
for TTS is higher in low-frequency cetaceans (i.e., mysticetes) than 
other marine mammal hearing groups and would be more likely to occur in 
frequency bands in which they communicate. However, we would not expect 
the TTS to span the entire communication or hearing range of any 
species given the frequencies produced by pile driving do not span 
entire hearing ranges for any particular species. Additionally, though 
the frequency range of TTS that marine mammals might sustain would 
overlap with some of the frequency ranges of their vocalizations, the 
frequency range of TTS from Revolution Wind's pile driving and UXO/MEC 
detonation activities would not typically span the entire frequency 
range of one vocalization type, much less span all types of 
vocalizations or other critical auditory cues for any given species. 
However, the mitigation measures proposed by Revolution Wind and 
proposed by NMFS, further reduce the potential for TTS in mysticetes.
    Generally, both the degree of TTS and the duration of TTS would be 
greater if the marine mammal is exposed to a higher level of energy 
(which would occur when the peak dB level is higher or the duration is 
longer). The threshold for the onset of TTS was discussed previously 
(refer back to Table 10). However, source level alone is not a 
predictor of TTS. An animal would have to approach closer to the source 
or remain in the vicinity of the sound source appreciably longer to 
increase the received SEL, which would be difficult considering the 
proposed mitigation and the nominal speed of the receiving animal 
relative to the stationary sources such as impact pile driving. The 
recovery time of TTS is also of importance when considering the 
potential impacts from TTS. In TTS laboratory studies (as discussed in 
the Potential Effects to Marine Mammals and their Habitat section), 
some using exposures of almost an hour in duration or up to 217 SEL, 
almost all individuals recovered within 1 day (or less, often in 
minutes) and we note that while the pile driving activities last for 
hours a day, it is unlikely that most marine mammals would stay in the 
close vicinity of the source long enough to incur more severe TTS. UXO/
MEC detonation also has the potential to result in TTS; however, given 
the duration of exposure is extremely short (milliseconds), the degree 
of TTS (i.e., the amount of dB shift) is expected to be small and TTS 
duration is expected to be short (minutes to hours). Overall, given the 
small number of times that any individual might incur TTS, the low 
degree of TTS and the short anticipated duration, and the unlikely 
scenario that any TTS overlapped the entirety of a critical hearing 
range, it is unlikely that

[[Page 79151]]

TTS of the nature expected to result from Revolution Wind's activities 
would result in behavioral changes or other impacts that would impact 
any individual's (of any hearing sensitivity) reproduction or survival.

Permanent Threshold Shift (PTS)

    Revolution Wind has requested, and NMFS proposed to authorize, a 
very small amount of take by PTS to some marine mammal individuals. The 
numbers of proposed annual takes by Level A harassment are relatively 
low for all marine mammal stocks and species: humpback whales (7 
takes), harbor porpoises (49 takes), gray seals (7 takes), and harbor 
seals (16 takes). The only activities incidental to which we anticipate 
PTS may occur is from exposure to impact pile driving and UXO/MEC 
detonations, which produce sounds that are both impulsive and primarily 
concentrated in the lower frequency ranges (below 1 kHz) (David, 2006; 
Krumpel et al., 2021).
    There are no PTS data on cetaceans and only one instance of PTS 
being induced in an older harbor seals (Reichmuth et al., 2019); 
however, available TTS data (of mid-frequency hearing specialists 
exposed to mid- or high-frequency sounds (Southall et al., 2007; NMFS 
2018; Southall et al., 2019)) suggest that most threshold shifts occur 
in the frequency range of the source up to one octave higher than the 
source. We would anticipate a similar result for PTS. Further, no more 
than a small degree of PTS is expected to be associated with any of the 
incurred Level A harassment, given it is unlikely that animals would 
stay in the close vicinity of a source for a duration long enough to 
produce more than a small degree of PTS.
    PTS would consist of minor degradation of hearing capabilities 
occurring predominantly at frequencies one-half to one octave above the 
frequency of the energy produced by pile driving or instantaneous UXO/
MEC detonation (i.e., the low-frequency region below 2 kHz) (Cody and 
Johnstone, 1981; McFadden, 1986; Finneran, 2015), not severe hearing 
impairment. If hearing impairment occurs from either impact pile 
driving or UXO/MEC detonation, 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. However, given sufficient notice 
through use of soft-start prior to implementation of full hammer energy 
during impact pile driving, marine mammals are expected to move away 
from a sound source that is annoying prior to it resulting in severe 
PTS. Revolution estimates up to 13 UXOs/MECs may be detonated and the 
exposure analysis assumes the worst-case scenario that all of the UXOs/
MECs found would consist of the largest charge weight of UXO/MEC (E12; 
454 kg). However, it is highly unlikely that all charges would be this 
maximum size, thus the amount of take incidental to the detonation of 
the 13 UXOs/MECs would likely be less than what is estimated here. 
Furthermore, Revolution Wind plans to implement sound attenuation 
during UXO/MEC detonations, to the extent practicable, that would 
further be expected to reduce take of marine mammals. Nonetheless, this 
negligible impact analysis considers the effects of the takes that are 
conservatively proposed for authorization.

Auditory Masking or Communication Impairment

    The ultimate potential impacts of masking on an individual are 
similar to those discussed for TTS (e.g., decreased ability to 
communicate, forage effectively, or detect predators), but an important 
difference is that masking only occurs during the time of the signal, 
versus TTS, which continues beyond the duration of the signal. Also, 
though, masking can result from the sum of exposure to multiple 
signals, none of which might individually cause TTS. Fundamentally, 
masking is referred to as a chronic effect because one of the key 
potential harmful components of masking is its duration--the fact that 
an animal would have reduced ability to hear or interpret critical cues 
becomes much more likely to cause a problem the longer it is occurring. 
Also inherent in the concept of masking is the fact that the potential 
for the effect is only present during the times that the animal and the 
source are in close enough proximity for the effect to occur (and 
further, this time period would need to coincide with a time that the 
animal was utilizing sounds at the masked frequency). As our analysis 
has indicated, for this project we expect that impact pile driving 
foundations have the greatest potential to mask marine mammal signals, 
and this pile driving may occur for several, albeit intermittent, hours 
per day. Masking is fundamentally more of a concern at lower 
frequencies (which are pile driving dominant frequencies), because low 
frequency signals propagate significantly further than higher 
frequencies and because they are more likely to overlap both the 
narrower low frequency calls of mysticetes, as well as many non-
communication cues related to fish and invertebrate prey, and geologic 
sounds that inform navigation. However, the area in which masking would 
occur for all marine mammal species and stocks (e.g., predominantly in 
the vicinity of the foundation pile being driven) is small relative to 
the extent of habitat used by each species and stock. In summary, the 
nature of Revolution Wind's activities, paired with habitat use 
patterns by marine mammals, does not support the likelihood that the 
level of masking that could occur would have the potential to affect 
reproductive success or survival.

Impacts on Habitat and Prey

    Construction activities or UXO/MEC detonation may result in fish 
and invertebrate mortality or injury very close to the source, and all 
activities (including HRG surveys) may cause some fish to leave the 
area of disturbance. It is anticipated that any mortality or injury 
would be limited to a very small subset of available prey and the 
implementation of mitigation measures such as the use of a noise 
attenuation system during impact pile driving and UXO/MEC detonation 
would further limit the degree of impact (again noting UXO/MEC 
detonation would be limited to 13 events over 5 years). Behavioral 
changes in prey in response to construction activities could 
temporarily impact marine mammals' foraging opportunities in a limited 
portion of the foraging range but, because of the relatively small area 
of the habitat that may be affected at any given time (e.g., around a 
pile being driven), the impacts to marine mammal habitat are not 
expected to cause significant or long-term negative consequences.
    Cable presence and operation are not anticipated to impact marine 
mammal habitat as these would be buried, and any electromagnetic fields 
emanating from the cables are not anticipated to result in consequences 
that would impact marine mammals prey to the extent they would be 
unavailable for consumption.
    The presence and operation of wind turbines within the lease area 
could have longer-term impacts on marine mammal habitat, as the project 
would result in the persistence of the structures within marine mammal 
habitat for more than 30 years. The presence and operation of an 
extensive number of structures such as wind turbines are, in general, 
likely to result in local and broader oceanographic effects in the 
marine environment, and may disrupt dense aggregations and distribution 
of marine mammal

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zooplankton prey through altering the strength of tidal currents and 
associated fronts, changes in stratification, primary production, the 
degree of mixing, and stratification in the water column (Chen et al., 
2021, Johnson et al., 2021, Christiansen et al., 2022, Dorrell et al., 
2022). However, the scale of impacts is difficult to predict and may 
vary from hundreds of meters for local individual turbine impacts 
(Schultze et al., 2020) to large-scale dipoles of surface elevation 
changes stretching hundreds of kilometers (Christiansen et al., 2022). 
In 2022, NMFS hosted a workshop to better understand the current 
scientific knowledge and data gaps around the potential long-term 
impacts of offshore wind farm operations in the Atlantic Ocean. The 
report from that workshop is pending and NMFS will consider its 
findings in development of the final rule for this action.
    As discussed in the Potential Effects to Marine Mammals and Their 
Habitat section, the RWF would consist of no more than 79 turbines 
(scheduled to be operational by Year 2 of the effective period of the 
rule) in New England coastal waters, an area dominated by physical 
oceanographic patterns of strong seasonal stratification (summer) and 
turbulence-driven mixing (winter). While there are likely to be local 
oceanographic impacts from the presence and operation of the RWF, 
meaningful oceanographic impacts relative to stratification and mixing 
that would significantly affect marine mammal habitat and prey over 
large areas in key foraging habitats are not anticipated from the 
Revolution Wind project. Although this area supports aggregations of 
zooplankton (baleen whale prey) that could be impacted if long-term 
oceanographic changes occurred, prey densities are typically 
significantly less in the Revolution Wind project area than in known 
baleen whale foraging habitats to the east and north (e.g., south of 
Nantucket and Martha's Vineyard, Great South Channel). For these 
reasons, if oceanographic features are affected by wind farm operation 
during the course of the proposed rule (approximately Years 2-5), the 
impact on marine mammal habitat and their prey is likely to be 
comparatively minor.

Mitigation To Reduce Impacts on All Species

    This proposed rulemaking includes a variety of mitigation measures 
designed to minimize impacts on all marine mammals, with a focus on 
North Atlantic right whales (the latter is described in more detail 
below). For impact pile driving of foundation piles, eight overarching 
mitigation measures are proposed, which are intended to reduce both the 
number and intensity of marine mammal takes: (1) seasonal/time of day 
work restrictions; (2) use of multiple PSOs to visually observe for 
marine mammals (with any detection within designated zones triggering 
delay or shutdown); (3) use of PAM to acoustically detect marine 
mammals, with a focus on detecting baleen whales (with any detection 
within designated zones triggering delay or shutdown); (4) 
implementation of clearance zones; (5) implementation of shutdown 
zones; (6) use of soft-start; (7) use of noise abatement technology; 
and, (8) maintaining situational awareness of marine mammal presence 
through the requirement that any marine mammal sighting(s) by 
Revolution Wind project personnel must be reported to PSOs.
    When monopile foundation installation does occur, Revolution Wind 
is committed to reducing the noise levels generated by impact pile 
driving to the lowest levels practicable and ensuring that they do not 
exceed a noise footprint above that which was modeled, assuming a 10-dB 
attenuation. Use of a soft-start would allow animals to move away from 
(i.e., avoid) the sound source prior to the elevation of the hammer 
energy to the level maximally needed to install the pile (Revolution 
Wind would not use a hammer energy greater than necessary to install 
piles). Clearance zone and shutdown zone implementation, required when 
marine mammals are within given distances associated with certain 
impact thresholds, would reduce the magnitude and severity of marine 
mammal take.
    Revolution Wind has indicated that up to three piles per day (i.e., 
12 hours of impact pile driving over 24 hours) could occur under ideal 
conditions; however, it is more likely that, given the complexities of 
installation, the average rate would be two piles per day (i.e., 8 
hours of activity pile driving per day). Revolution Wind has indicated 
that a monopile installation sequence would occur over up to nine 
hours; however, this entire period would not consist of active 
hammering, as a considerable portion of this time would be needed to 
move vessels and equipment to set up additional monopiles. 
Specifically, the application notes that ``installation of a single 
pile at a minimum would involve a 1-hour pre-clearance period, up to 4 
hours of piling, and 4 hours to move to the next piling location where 
the process would begin again.'' The full 9-hour installation sequence 
period would also consist of other activities outside of active impact 
driving that are not likely to harass marine mammals (e.g., vessel 
transit, equipment set-up, pre-clearance monitoring by visual PSOs and 
PAM operators).
    Revolution proposed, and NMFS would require, use a noise 
attenuation device (likely a big bubble curtain and another technology, 
such as a hydro-sound damper) during all foundation pile driving to 
ensure sound generated from the project does not exceed that modeled 
(assuming 10-dB reduction) distances to harassment isopleths and to 
minimize noise levels to the lowest level practicable. Double big 
bubble curtains are successfully and widely applied across European 
wind development efforts, and are known to reduce noise levels more 
than a single big bubble curtain alone (e.g., see Bellman et al., 
2020).

Mysticetes

    Six mysticete species (comprising six stocks) of cetaceans (North 
Atlantic right whale, humpback whale, fin whale, blue whale, sei whale, 
and minke whale) are proposed to be taken by harassment. These species, 
to varying extents, utilize coastal New England waters, including the 
project area, for the purposes of migration and foraging.
    Behavioral data on mysticete reactions to pile driving noise is 
scant. Kraus et al. (2019) predicted that the three main impacts of 
offshore wind farms on marine mammals would consist of displacement, 
behavioral disruptions, and stress. Broadly, we can look to studies 
that have focused on other noise sources such as seismic surveys and 
military training exercises, which suggest that exposure to loud 
signals can result in avoidance of the sound source (or displacement if 
the activity continues for a longer duration in a place where 
individuals would otherwise have been staying, which is less likely for 
mysticetes in this area), disruption of foraging activities (if they 
are occurring in the area), local masking around the source, associated 
stress responses, and impacts to prey, as well as TTS or PTS in some 
cases.
    Mysticetes encountered in the Revolution Wind project area are 
expected to be migrating through and/or foraging within the project 
area; the extent to which an animal engages in these behaviors in the 
area is species-specific and varies seasonally. Given that extensive 
feeding BIAs for the North Atlantic right whale, humpback whale, fin 
whale, sei whale, and minke whale exist to the east and north of the 
project area (LaBrecque et al., 2015; Van Parijs et al., 2015), many 
mysticetes are expected to predominantly be migrating through the 
project area towards or from

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these feeding habitats. However, the extent to which particular species 
are utilizing the project area and nearby habitats (i.e., south of 
Martha's Vineyard and Nantucket) for foraging or other activities is 
changing, particularly right whales (e.g., O'Brien et al., 2021; 
Quintana-Rizzo et al., 2021), thus our understanding of the temporal 
and spatial occurrence of right whales and other mysticete species is 
continuing to be informed by ongoing monitoring efforts. While we have 
acknowledged above that mortality, hearing impairment, or displacement 
of mysticete prey species may result locally from impact pile driving 
or UXO/MEC detonation, given the very short duration of UXO/MEC 
detonation and limited amount over 5 years, and broad availability of 
prey species in the area and the availability of alternative suitable 
foraging habitat for the mysticete species most likely to be affected, 
any impacts on mysticete foraging would be expected to be minor. Whales 
temporarily displaced from the proposed project area would be expected 
to have sufficient remaining feeding habitat available to them, and 
would not be prevented from feeding in other areas within the 
biologically important feeding habitats. In addition, any displacement 
of whales or interruption of foraging bouts would be expected to be 
temporary in nature.
    The potential for repeated exposures is dependent upon the 
residency time of whales, with migratory animals unlikely to be exposed 
on repeated occasions and animals remaining in the area to be more 
likely exposed repeatedly. Where relatively low amounts of species-
specific proposed Level B harassment are predicted (compared to the 
abundance of each mysticete species or stock, such as is indicated in 
Table 34 here) and movement patterns suggest that individuals would not 
necessarily linger in a particular area for multiple days, each 
predicted take likely represents an exposure of a different individual; 
the behavioral impacts would, therefore, be expected to occur within a 
single day within a year--an amount that would not be expected to 
impact reproduction or survival. Alternatively, species with longer 
residence time in the project area may be subject to repeated 
exposures. In general, for this project, the duration of exposures 
would not be continuous throughout any given day and pile driving would 
not occur on all consecutive days within a given year, due to weather 
delays or any number of logistical constraints Revolution Wind has 
identified. Species-specific analysis regarding potential for repeated 
exposures and impacts is provided below. Overall, we do not expect 
impacts to whales within project area habitat, including fin whales 
foraging in the fin whale feeding BIA, to affect the fitness of any 
large whales.
    The humpback whale is the only mysticete species for which PTS is 
anticipated and proposed to be authorized. As described previously, PTS 
for mysticetes from impact pile driving may overlap frequencies used 
for communication, navigation, or detecting prey. However, given the 
nature and duration of the activity, the mitigation measures, and 
likely avoidance behavior, any PTS is expected to be of a small degree, 
would be limited to frequencies where pile driving noise is 
concentrated (i.e., only a small subset of their expected hearing 
range) and would not be expected to impact reproductive success or 
survival.

North Atlantic Right Whales

    North Atlantic right whales are listed as endangered under the ESA 
and, as described in the Effects to Marine Mammals and Their Habitat 
section, are threatened by a low population abundance, higher than 
average mortality rates, and lower than average reproductive rates. 
Recent studies have reported individuals showing high stress levels 
(e.g., Corkeron et al., 2017) and poor health, which has further 
implications on reproductive success and calf survival (Christiansen et 
al., 2020; Stewart et al., 2021; Stewart et al., 2022). Given this, the 
status of the North Atlantic right whale population is of heightened 
concern and, therefore, merits additional analysis and consideration. 
NMFS proposes to authorize a maximum of 44 takes of North Atlantic 
right whales, by Level B harassment only, in any given year (likely 
Year 1), with no more than 56 takes incidental to all construction 
activities over the 5-year period of effectiveness of this proposed 
rule.
    As described above, the project area represents part of an 
important migratory and potential feeding area for right whales. 
Quintana-Rizzo et al. (2021) noted different degrees of residency 
(i.e., the minimum number of days an individual remained in southern 
New England) for right whales, with individual sighting frequency 
ranging from 1 to 10 days. The study results indicate that southern New 
England may, in part, be a stopover site for migrating right whales 
moving to or from southeastern calving grounds. The right whales 
observed during the study period were primarily concentrated in the 
northeastern and southeastern sections of the MA WEA during the summer 
(June-August) and winter (December-February), rather than in OCS-A 
0486, which is to the west in the RI/MA WEA (see Figure 5 in Quintano-
Rizzo et al., 2021). Right whale distribution did shift to the west 
into the RI/MA WEA in the spring (March-May), although sightings within 
the Revolution Wind project area were few compared to other portions of 
the WEA during this time. Overall, the Revolution Wind project area 
contains habitat less frequently utilized by North Atlantic right 
whales than the more easterly Southern New England region.
    In general, North Atlantic right whales in southern New England are 
expected to be engaging in migratory or foraging behavior (Quintano-
Rizzo et al., 2021). Model outputs suggest that 23 percent of the 
species' population is present in this region from December through 
May, and the mean residence time has tripled to an average of 13 days 
during these months. Given the species' migratory behavior in the 
project area, we anticipate individual whales would be typically 
migrating through the area during most months when foundation 
installation and UXO/MEC detonation would occur (given the seasonal 
restrictions on foundation installation from January through April and 
UXO/MEC detonation from December through April), rather than lingering 
for extended periods of time. Other work that involves either much 
smaller harassment zones (e.g., HRG surveys) or is limited in amount 
(cable landfall construction) may occur during periods when North 
Atlantic right whales are using the habitat for both migration and 
foraging. Therefore, it is likely that many of the exposures would 
occur to individual whales; however, some may be repeat takes of the 
same animal across multiple days for some short period of time given 
residency data (e.g., 13 days during December through May). It is 
important to note the activities occurring from December through May 
that may impact North Atlantic right whale would be primarily HRG 
surveys and cable landfall construction, neither of which would result 
in very high received levels. Across all years, while it is possible an 
animal could have been exposed during a previous year, the low amount 
of take proposed to be authorized during the 5-year period of the 
proposed rule makes this scenario possible but unlikely. However, if an 
individual were to be exposed during a subsequent year, the impact of 
that exposure is likely independent of the previous exposure given the 
duration between exposures.

[[Page 79154]]

    North Atlantic right whales are presently experiencing an ongoing 
UME (beginning in June 2017). Preliminary findings support human 
interactions, specifically vessel strikes and entanglements, as the 
cause of death for the majority of North Atlantic right whales. Given 
the current status of the North Atlantic right whale, the loss of even 
one individual could significantly impact the population. No mortality, 
serious injury, or injury of North Atlantic right whales as a result of 
the project is expected or proposed to be authorized. Any disturbance 
to North Atlantic right whales due to Revolution Wind's activities is 
expected to result in temporary avoidance of the immediate area of 
construction. As no injury, serious injury, or mortality is expected or 
authorized, and Level B harassment of North Atlantic right whales will 
be reduced to the level of least practicable adverse impact through use 
of mitigation measures, the authorized number of takes of North 
Atlantic right whales would not exacerbate or compound the effects of 
the ongoing UME in any way.
    As described in the general Mysticete section above, impact pile 
driving (assuming WTG and OSS monopile build-out) has the potential to 
result in the highest amount of annual take (44 Level B harassment 
takes) and is of greatest concern given loud source levels. This 
activity would likely be limited to 1 year, during times when North 
Atlantic right whales are not present in high numbers and are likely to 
be primarily migrating to more northern foraging grounds, with the 
potential for some foraging occurring in or near the project area. The 
potential types, severity, and magnitude of impacts are also 
anticipated to mirror that described in the general mysticete section 
above, including avoidance (the most likely outcome), changes in 
foraging or vocalization behavior, masking, a small amount of TTS, and 
temporary physiological impacts (e.g., change in respiration, change in 
heart rate). Importantly, the effects of the activities proposed by 
Revolution Wind are expected to be sufficiently low-level and localized 
to specific areas as to not meaningfully impact important behaviors 
such as migratory or foraging behavior of North Atlantic right whales. 
As described above, 56 total instances of take are proposed for 
authorization, each occurring within a day, with the majority of takes 
(44) occurring within 1 year and the remaining 12 occurring over the 
remaining four years of the effective period of the rule. If this 
number of exposures results in temporary behavioral reactions, such as 
slight displacement (but not abandonment) of migratory habitat or 
temporary cessation of feeding, it is unlikely to result in energetic 
consequences that could affect reproduction or survival of any 
individuals. As described above, North Atlantic right whales are 
primarily foraging during December through May when the vast majority 
of take from impact pile driving would not occur (given the seasonal 
restriction from January 1-April 31). Overall, NMFS expects that any 
harassment of North Atlantic right whales incidental to the specified 
activities would not result in changes to their migration patterns or 
foraging behavior, as only temporary avoidance of an area during 
construction is expected to occur. As described previously, right 
whales migrating through and/or foraging in these areas are not 
expected to remain in this habitat for extensive durations, relative to 
nearby habitats such as south of Nantucket and Martha's Vineyard or the 
Great South Channel (known core foraging habitats) (Quintana-Rizzo et 
al., 2021), and that any temporarily displaced animals would be able to 
return to or continue to travel through and forage in these areas once 
activities have ceased.
    Although acoustic masking may occur, based on the acoustic 
characteristics of noise associated with pile driving (e.g., frequency 
spectra, short duration of exposure) and construction surveys (e.g., 
intermittent signals), NMFS expects masking effects to be minimal 
(e.g., impact or vibratory pile driving) to none (e.g., construction 
surveys). In addition, masking would likely only occur during the 
period of time that a North Atlantic right whale is in the relatively 
close vicinity of pile driving, which is expected to be infrequent and 
brief, given time of year restrictions, anticipated mitigation 
effectiveness, and likely avoidance behaviors. TTS is another potential 
form of Level B harassment that could result in brief periods of 
slightly reduced hearing sensitivity, affecting behavioral patterns by 
making it more difficult to hear or interpret acoustic cues within the 
frequency range (and slightly above) of sound produced during impact 
pile driving; however, any TTS would likely be of low amount, be 
limited to frequencies where most construction noise is centered (below 
2 kHz). NMFS expects that right whale hearing sensitivity would return 
to pre-exposure levels shortly after migrating through the area or 
moving away from the sound source.
    As described in the Potential Effects to Marine Mammals and Their 
Habitat section, the distance of the receiver to the source influences 
the severity of response with greater distances typically eliciting 
less severe responses. Additionally, NMFS recognizes North Atlantic 
right whales migrating could be pregnant females (in the fall) and cows 
with older calves (in spring) and that these animals may slightly alter 
their migration course in response to any foundation pile driving; 
however, as described in the Potential Effects to Marine Mammals and 
Their Habitat section, we anticipate that course diversion would be of 
small magnitude. Hence, while some avoidance of the pile driving 
activities may occur, we anticipate any avoidance behavior of migratory 
right whales would be similar to that of gray whales (Tyack and Clark, 
1983), on the order of hundreds of meters up to 1 to 2 km. This 
diversion from a migratory path otherwise uninterrupted by Revolution 
Wind activities, or from lower quality foraging habitat (relative to 
nearby areas), is not expected to result in meaningful energetic costs 
that would impact annual rates of recruitment of survival. NMFS expects 
that North Atlantic right whales would be able to avoid areas during 
periods of active noise production, while not being forced out of this 
portion of their habitat.
    North Atlantic right whale presence in the Revolution Wind project 
area is year-round; however, abundance during summer months is lower 
compared to the winter months, with spring and fall serving as 
``shoulder seasons,'' wherein abundance waxes (fall) or wanes (spring). 
Given this year-round habitat usage, in recognition that where and when 
whales may actually occur during project activities is unknown as it 
depends on the annual migratory behaviors, the applicant has proposed 
and NMFS is proposing to require a suite of mitigation measures 
designed to reduce impacts to North Atlantic right whales to the 
maximum extent practicable. These mitigation measures (e.g., seasonal/
daily work restrictions, vessel separation distances, reduced vessel 
speed) would not only avoid the likelihood of ship strikes, but also 
would minimize the severity of behavioral disruptions by minimizing 
impacts (e.g., through sound reduction using abatement systems and 
reduced temporal overlap of project activities and North Atlantic right 
whales). This would further ensure that the number of takes, by Level B 
harassment, that are estimated to occur are not expected to affect 
reproductive success or

[[Page 79155]]

survivorship via detrimental impacts to energy intake or cow/calf 
interactions during migratory transit. However, even in consideration 
of recent habitat-use and distribution shifts, Revolution Wind would 
still be installing monopiles when the presence of North Atlantic right 
whales is expected to be lower.
    As described in the Description of Marine Mammals in the Area of 
Specified Activities section, Revolution Wind would be constructed 
within the North Atlantic right whale migratory corridor BIA which 
represent areas and months within which a substantial portion of a 
species or population is known to migrate. Off the south coast of 
Massachusetts and Rhode Island, this BIA extends from the coast to 
beyond the shelf break. The Revolution Wind project area is relatively 
small compared with the migratory BIA area (approximately 339 km\2\ 
versus the size of the full North Atlantic right whale migratory BIA, 
269,448 km\2\). Because of this, overall North Atlantic right whale 
migration is not expected to be impacted by the proposed activities. 
There are no known North Atlantic right whale mating or calving areas 
within the project area. Impact pile driving, which is responsible for 
the majority of North Atlantic right whale impacts, would be limited to 
a maximum of 12 hours per day (three intermittent 4-hour events); 
therefore, if foraging activity is disrupted due to pile driving, any 
disruption would be brief as North Atlantic right whales would likely 
resume foraging after pile driving ceases or when animals move to 
another nearby location to forage. Prey species are mobile (e.g., 
calanoid copepods can initiate rapid and directed escape responses) and 
are broadly distributed throughout the project area (noting again that 
North Atlantic right whale prey is not particularly concentrated in the 
project area relative to nearby habitats); therefore, any impacts to 
prey that may occur are also unlikely to impact marine mammals.
    The most significant measure to minimize impacts to individual 
North Atlantic right whales during monopile installations is the 
seasonal moratorium on impact pile driving of monopiles from January 1 
through April 30, when North Atlantic right whale abundance in the 
project area is expected to be highest. NMFS also expects this measure 
to greatly reduce the potential for mother-calf pairs to be exposed to 
impact pile driving noise above the Level B harassment threshold during 
their annual spring migration through the project area from calving 
grounds to primary foraging grounds (e.g., Cape Cod Bay). Further, NMFS 
expects that exposures to North Atlantic right whales would be reduced 
due to the additional proposed mitigation measures that would ensure 
that any exposures above the Level B harassment threshold would result 
in only short-term effects to individuals exposed. Impact pile driving 
may only begin in the absence of North Atlantic right whales (based on 
visual and passive acoustic monitoring). If impact pile driving has 
commenced, NMFS anticipates North Atlantic right whales would avoid the 
area, utilizing nearby waters to carry on pre-exposure behaviors. 
However, impact pile driving must be shut down if a North Atlantic 
right whale is sighted at any distance, unless a shutdown is not 
feasible due to risk of injury or loss of life. Shutdown may occur 
anywhere if right whales are seen within or beyond the Level B 
harassment zone, further minimizing the duration and intensity of 
exposure. NMFS anticipates that if North Atlantic right whales go 
undetected and they are exposed to impact pile driving noise, it is 
unlikely a North Atlantic right whale would approach the impact pile 
driving locations to the degree that they would purposely expose 
themselves to very high noise levels. These measures are designed to 
avoid PTS and also reduce the severity of Level B harassment, including 
the potential for TTS. While some TTS could occur, given the proposed 
mitigation measures (e.g., delay pile driving upon a sighting or 
acoustic detection and shutting down upon a sighting or acoustic 
detection), the potential for TTS to occur is low.
    The proposed clearance and shutdown measures are most effective 
when detection efficiency is maximized, as the measures are triggered 
by a sighting or acoustic detection. To maximize detection efficiency, 
Revolution Wind proposed, and NMFS is proposed to require, the 
combination of PAM and visual observers (as well as communication 
protocols with other Revolution Wind vessels, and other heightened 
awareness efforts such as daily monitoring of North Atlantic right 
whale sighting databases) such that as a North Atlantic right whale 
approaches the source (and thereby could be exposed to higher noise 
energy levels), PSO detection efficacy would increase, the whale would 
be detected, and a delay to commencing pile driving or shutdown (if 
feasible) would occur. In addition, the implementation of a soft start 
would provide an opportunity for whales to move away from the source if 
they are undetected, reducing received levels. Further, Revolution Wind 
has committed to not installing two WTG or OSS foundations 
simultaneously. North Atlantic right whales would, therefore, not be 
exposed to concurrent impact pile driving on any given day and the area 
ensonified at any given time would be limited. We note that Revolution 
Wind has requested to install foundation piles at night which does 
raise concern over detection capabilities. Revolution Wind is currently 
conducting detection capability studies using alternative technology 
and intends to submit the results of these studies to NMFS. In 
consultation with BOEM, NMFS will review the results and determine if 
Revolution Wind should be allowed to conduct pile driving at night.
    Although the temporary cofferdam Level B harassment zone is large 
(9,740 km to the unweighted Level B harassment threshold; Table 27 in 
the ITA application), the cofferdams would be installed within 
Narragansett Bay over a short timeframe (56 hours total; 28 hours for 
installation and 28 hours for removal). Therefore, it is also unlikely 
that any North Atlantic right whales would be exposed to concurrent 
vibratory and impact pile installation noises. Any UXO/MEC detonations, 
if determined to be necessary, would only occur in daylight and if all 
other low-order methods or removal of the explosive equipment of the 
device are determined to not be possible. Given that specific locations 
for the 13 possible UXOs/MECs are not presently known, Revolution Wind 
has agreed to undertake specific mitigation measures to reduce impacts 
on any North Atlantic right whales, including the use of a sound 
attenuation device (i.e., likely a bubble curtain and another device) 
to achieve a minimum of 10-dB attenuation, and not detonating a UXO/MEC 
if a North Atlantic right whale is observed within the large whale 
clearance zone (10 km). Finally, for HRG surveys, the maximum distance 
to the Level B harassment isopleth is 141 m. The estimated take, by 
Level B harassment only, associated with HRG surveys is to account for 
any North Atlantic right whale sightings PSOs may miss when HRG 
acoustic sources are active. However, because of the short maximum 
distance to the Level B harassment isopleth (141 m), the requirement 
that vessels maintain a distance of 500 m from any North Atlantic right 
whales, the fact whales are unlikely to remain in close proximity to an 
HRG survey vessel for any length of time, and that the acoustic source 
would be shutdown if a North Atlantic right whale is observed within 
500 m of the source, any exposure to noise levels above the harassment

[[Page 79156]]

threshold (if any) would be very brief. To further minimize exposures, 
ramp-up of boomers, sparkers, and CHIRPs must be delayed during the 
clearance period if PSOs detect a North Atlantic right whale (or any 
other ESA-listed species) within 500 m of the acoustic source. With 
implementation of the proposed mitigation requirements, take by Level A 
harassment is unlikely and, therefore, not proposed for authorization. 
Potential impacts associated with Level B harassment would include low-
level, temporary behavioral modifications, most likely in the form of 
avoidance behavior. Given the high level of precautions taken to 
minimize both the amount and intensity of Level B harassment on North 
Atlantic right whales, it is unlikely that the anticipated low-level 
exposures would lead to reduced reproductive success or survival.
    North Atlantic right whales are listed as endangered under the ESA 
with a declining population primarily due to vessel strike and 
entanglement. Again, Revolution estimates that 44 instances of take, by 
Level B harassment only, could occur within the first year, and 56 
instances of take could occur over the 5-year effective period of the 
proposed rule, with the likely scenario that each instance of exposure 
occurs to a different individual (a small portion of the stock), and 
any individual North Atlantic right whale is likely to be disturbed at 
a low-moderate level. The magnitude and severity of harassment are not 
expected to result in impacts on the reproduction or survival of any 
individuals, let alone have impacts on annual rates of recruitment or 
survival of this stock. No mortality, serious injury, or Level A 
harassment is anticipated or proposed to be authorized. For these 
reasons, we have preliminarily determined, in consideration of all of 
the effects of the Revolution Wind's activities combined, that the 
proposed authorized take would have a negligible impact on the North 
Atlantic stock of North Atlantic right whales.
Humpback Whales
    Humpback whales potentially impacted by Revolution Wind's 
activities do not belong to a DPS that is listed as threatened or 
endangered under the ESA. However, humpback whales along the Atlantic 
Coast have been experiencing an active UME as elevated humpback whale 
mortalities have occurred along the Atlantic coast from Maine through 
Florida since January 2016. Of the cases examined, approximately half 
had evidence of human interaction (ship strike or entanglement). The 
UME does not yet provide cause for concern regarding population-level 
impacts, and take from ship strike and entanglement is not proposed to 
be authorized. Despite the UME, the relevant population of humpback 
whales (the West Indies breeding population, or DPS of which the Gulf 
of Maine stock is a part) remains stable at approximately 12,000 
individuals.
    Revolution Wind has requested, and NMFS has proposed to authorize, 
a limited amount of humpback whale harassment, by Level A harassment 
and Level B harassment. No mortality or serious injury is anticipated 
or proposed for authorization. Among the activities analyzed, impact 
pile driving has the potential to result in the highest amount of 
annual take of humpback whales (7 takes by Level A harassment and 48 
takes by Level B harassment) and is of greatest concern, given the 
associated loud source levels. Kraus et al. (2016) reported humpback 
whale sightings in the RI-MA WEA during all seasons, with peak 
abundance during the spring and early summer, but their presence within 
the region varies between years. Increased presence of sand lance 
(Ammodytes spp.) appears to correlate with the years in which most 
whales were observed, suggesting that humpback whale distribution and 
occurrence could largely be influenced by prey availability (Kenney and 
Vigness-Raposa 2010, 2016). Seasonal abundance estimates of humpback 
whales in the RI-MA WEA range from 0 to 41 (Kraus et al., 2016), with 
higher estimates observed during the spring and summer. Davis et al. 
(2020) found the greatest number of acoustic detections in southern New 
England in the winter and spring, with a noticeable decrease in 
acoustic detections during most summer and fall months. This data 
suggests that the 7 and 48 maximum annual instances of predicted to 
take by Level A harassment and Level B harassment, respectively, could 
consist of individuals exposed to noise levels above the harassment 
thresholds once during migration through the project area and/or 
individuals exposed on multiple days if they are utilizing the area as 
foraging habitat. Based on the observed peaks in humpback whale 
seasonal distribution in the RI/MA WEA, it is likely that these 
individuals would primarily be exposed to HRG survey activities, 
landfall construction activities, and to a lesser extent, impact pile 
driving and UXO/MEC detonations (given the seasonal restrictions on the 
latter two activities). Any such exposures would occur either singly, 
or intermittently, but not continuously throughout a day.
    For all the reasons described in the Mysticete section above, we 
anticipate any potential PTS or TTS would be small (limited to a few 
dB) and concentrated at half or one octave above the frequency band of 
pile driving noise (most sound is below 2 kHz) which does not include 
the full predicted hearing range of baleen whales. If TTS is incurred, 
hearing sensitivity would likely return to pre-exposure levels shortly 
after exposure ends. Any masking or physiological responses would also 
be of low magnitude and severity for reasons described above.
    Altogether, the amount of take proposed to be authorized is small, 
and the low magnitude and severity of harassment effects is not 
expected to result in impacts on the reproduction or survival of any 
individuals, let alone have impacts on annual rates of recruitment or 
survival of this stock. No mortality or serious injury is anticipated 
or proposed to be authorized. For these reasons, we have preliminarily 
determined, in consideration of all of the effects of the Revolution 
Wind's activities combined, that the proposed authorized take would 
have a negligible impact on the Gulf of Maine stock of humpback whales.
Fin Whale
    The western North Atlantic stock of fin whales is listed as 
endangered under the ESA. The 5-year total amount of take, by Level B 
harassment, of fin whales (n=48) NMFS proposes to authorize is low 
relative to the stock abundance. Any Level B harassment is expected to 
be in the form of behavioral disturbance, primarily resulting in 
avoidance of the project area where pile driving is occurring, and some 
low-level TTS and masking that may limit the detection of acoustic cues 
for relatively brief periods of time. No Level A harassment, serious 
injury, or mortality is anticipated or proposed for authorization. As 
described previously, the project area overlaps 11 percent of a small 
fin whale feeding BIA (March-October; 2,933 km\2\) located east of 
Montauk Point, New York (Figure 2.3 in LaBrecque et al., 2015). 
Although the RWF and a portion of the RWEC would be constructed within 
the fin whale foraging BIA, the BIA is considerably larger than the 
relatively small area within which impacts from monopile installations 
or UXO/MEC detonations may occur; this difference in scale would 
provide ample access to foraging opportunities for fin whales within 
the remaining area of the BIA. In addition, monopile installations and 
UXO/MEC

[[Page 79157]]

detonations have seasonal/daily work restrictions, such that the 
temporal overlap between these project activities and the BIA timeframe 
does not include the months of March or April. Acoustic impacts from 
landfall construction would be limited to Narragansett Bay, within 
which fin whales are not expected to occur. A second larger yearlong 
feeding BIA (18,015 km\2\) extends from the Great South Channel (east 
of the smaller fin whale feeding BIA) north to southern Maine. Any 
disruption of feeding behavior or avoidance of the western BIA by fin 
whales from May to October is expected to be temporary, with habitat 
utilization by fin whales returning to baseline once the construction 
activities cease. The larger fin whale feeding BIA would provide 
suitable alternate habitat and ample foraging opportunities 
consistently throughout the year, rather than seasonally like the 
smaller, western BIA.
    Because of the relatively low magnitude and severity of take 
proposed for authorization, the fact that no serious injury or 
mortality is anticipated, the temporary nature of the disturbance, and 
the availability of similar habitat and resources in the surrounding 
area, NMFS has preliminarily determined that the impacts of Revolution 
Wind's activities on fin whales and the food sources that they utilize 
are not expected to cause significant impacts on the reproduction or 
survival of any individuals, let alone have impacts on annual rates of 
recruitment or survival of this stock.
Blue and Sei Whales
    The Western North Atlantic stock of blue whales and the Nova Scotia 
stock of sei whales are also listed under the ESA. There are no known 
areas of specific biological importance in or around the project area, 
nor are there any UMEs. For both species, the actual abundance of each 
stock is likely significantly greater than what is reflected in each 
SAR because, as noted in the SARs, the most recent population estimates 
are primarily based on surveys conducted in U.S. waters and both 
stocks' range extends well beyond the U.S. Exclusive Economic Zone 
(EEZ).
    The 5-year total amount of take, by Level B harassment, proposed 
for authorization for blue whales (n=7) and sei whales (n=26) is low, 
and no potential Level A harassment take is anticipated or proposed for 
authorization for either species. Similar to other mysticetes, we would 
anticipate the number of takes to represent individuals taken only once 
or, in rare cases, an individual taken a very small number of times as 
most whales in the project area would be migrating. To a small degree, 
sei whales may forage in the project area, although the currently 
identified foraging habitats (BIAs) are to the east and north of the 
area in which Revolution Wind's activities would occur (LaBrecque et 
al., 2015). With respect to the severity of those individual takes by 
behavioral Level B harassment, we would anticipate impacts to be 
limited to low-level, temporary behavioral responses with avoidance and 
potential masking impacts in the vicinity of the turbine installation 
to be the most likely type of response. Any avoidance of the project 
area due to Revolution Wind's activities would be expected to be 
limited.
    Overall, the take by harassment proposed for authorization is of a 
low magnitude and severity and is not expected to result in impacts on 
the reproduction or survival of any individuals, let alone have impacts 
on annual rates of recruitment or survival of this stock. No mortality 
or serious injury is anticipated or proposed to be authorized. For 
these reasons, we have preliminarily determined, in consideration of 
all of the effects of the Revolution Wind's activities combined, that 
the proposed authorized take would have a negligible impact on the 
Western North Atlantic blue whale stock and the Nova Scotia sei whale 
stock.
Minke Whales
    The Canadian East Coast stock of minke whales is not listed under 
the ESA. There are no known areas of specific biological importance in 
or around the project area. Beginning in January 2017, elevated minke 
whale strandings have occurred along the Atlantic coast from Maine 
through South Carolina, with highest numbers in Massachusetts, Maine, 
and New York. This event does not provide cause for concern regarding 
population level impacts, as the likely population abundance is greater 
than 21,000 whales. No mortality or serious injury of this stock is 
anticipated or proposed for authorization.
    Minke whales may be taken by Level B harassment; however, this 
would be limited to a relatively low number of individuals annually, 
with the maximum annual take of 304 minke whales estimated for the 
first year of construction and a maximum 320 across all 5 years. We 
anticipate the impacts of this harassment to follow those described in 
the general Mysticete section above. In summary, Level B harassment 
would be temporary, with primary impacts being temporary displacement 
of the project area but not abandonment of any migratory or foraging 
behavior. Overall, the amount of take proposed to be authorized is 
small and the low magnitude and severity of harassment effects is not 
expected to result in impacts on the reproduction or survival of any 
individuals, let alone have impacts on annual rates of recruitment or 
survival of this stock. No mortality or serious injury is anticipated 
or proposed to be authorized. For these reasons, we have preliminarily 
determined, in consideration of all of the effects of the Revolution 
Wind's activities combined, that the proposed authorized take would 
have a negligible impact on the Canadian East Coast stock of minke 
whales.

Odontocetes

    In this section, we include information here that applies to all of 
the odontocete species and stocks addressed below, which are further 
divided into the following subsections: Sperm whales, Dolphins and 
small whales; and Harbor porpoises. These sub-sections include more 
specific information, as well as conclusions for each stock 
represented.
    The majority of takes by harassment of odontocetes incidental to 
Revolution Wind's specified activities are by Level B harassment 
incidental to pile driving and HRG surveys. We anticipate that, given 
ranges of individuals (i.e., that some individuals remain within a 
small area for some period of time), and non-migratory nature of some 
odontocetes in general (especially as compared to mysticetes), these 
takes are more likely to represent multiple exposures of a smaller 
number of individuals than is the case for mysticetes, though some 
takes may also represent one-time exposures to an individual.
    Pile driving, particularly impact pile driving foundation piles, 
has the potential to disturb odontocetes to the greatest extent, 
compared to HRG surveys and UXO/MEC detonations. While we do expect 
animals to avoid the area during pile driving, their habitat range is 
extensive compared to the area ensonified during pile driving.
    As described earlier, Level B harassment may manifest as changes to 
behavior (e.g., avoidance, changes in vocalizations (from masking) or 
foraging), physiological responses, or TTS. Odontocetes are highly 
mobile species and, similar to mysticetes, NMFS expects any avoidance 
behavior to be limited to the area near the pile being driven. While 
masking could occur during pile driving, it would only occur in the 
vicinity of and during the duration of the pile driving, and would

[[Page 79158]]

not generally occur in a frequency range that overlaps most odontocete 
communication or echolocation signals. The mitigation measures (e.g., 
use of sound abatement systems, implementation of clearance and 
shutdown zones) would also minimize received levels such that the 
severity of any behavioral response would be expected to be less than 
exposure to unmitigated noise exposure.
    Any masking or TTS effects are anticipated to be of low-severity. 
First, the frequency range of pile driving, the most impactful activity 
conducted by Revolution Wind in terms of response severity, falls 
within a portion of the frequency range of most odontocete 
vocalizations. However, odontocete vocalizations span a much wider 
range than the low frequency construction activities proposed by 
Revolution Wind. Further, as described above, recent studies suggest 
odontocetes have a mechanism to self-mitigate (i.e., reduce hearing 
sensitivity) the impacts of noise exposure, which could potentially 
reduce TTS impacts. Any masking or TTS is anticipated to be limited and 
would typically only interfere with communication within a portion of 
an odontocete's range and as discussed earlier, the effects would only 
be expected to be of a short duration and, for TTS, a relatively small 
degree. Furthermore, odontocete echolocation occurs predominantly at 
frequencies significantly higher than low frequency construction 
activities; therefore, there is little likelihood that threshold shift, 
either temporary or permanent, would interfere with feeding behaviors 
(noting that take by Level A harassment (PTS) is proposed for only 
harbor porpoises). For HRG surveys, the sources operate at higher 
frequencies than pile driving and UXO/MEC detonations; however, sounds 
from these sources attenuate very quickly in the water column, as 
described above; therefore, any potential for TTS and masking is very 
limited. Further, odontocetes (e.g., common dolphins, spotted dolphins, 
bottlenose dolphins) have demonstrated an affinity to bow-ride actively 
surveying HRG surveys; therefore, the severity of any harassment, if it 
does occur, is anticipated to be minimal based on the lack of avoidance 
previously demonstrated by these species.
    The waters off the coast of Rhode Island are used by several 
odontocete species; however, none (except the sperm whale) are listed 
under the ESA and there are no known habitats of particular importance. 
In general, odontocete habitat ranges are far-reaching along the 
Atlantic coast of the U.S., and the waters off of Rhode Island, 
including the project area, do not contain any particularly unique 
odontocete habitat features.
Sperm Whale
    The Western North Atlantic stock of sperm whales spans the East 
Coast out into oceanic waters well beyond the U.S. EEZ. Although listed 
as endangered, the primary threat faced by the sperm whale (i.e., 
commercial whaling) has been eliminated and, further, sperm whales in 
the western North Atlantic were little affected by modern whaling 
(Taylor et al., 2008). Current potential threats to the species 
globally include vessel strikes, entanglement in fishing gear, 
anthropogenic noise, exposure to contaminants, climate change, and 
marine debris. There is no currently reported trend for the stock and, 
although the species is listed as endangered under the ESA, there are 
no specific issues with the status of the stock that cause particular 
concern (e.g., no UMEs). There are no known areas of biological 
importance (e.g., critical habitat or BIAs) in or near the project 
area.
    No mortality, serious injury or Level A harassment is anticipated 
or proposed to be authorized for this species. Impacts would be limited 
to Level B harassment and would occur to only a very small number of 
individuals (maximum of 7 per year or 15 across all 5 years) incidental 
to pile driving, UXO/MEC detonation(s), and HRG surveys. Sperm whales 
are not common within the project area due to the shallow waters, and 
it is not expected that any noise levels would reach habitat in which 
sperm whales are common, including deep-water foraging habitat. If 
sperm whales do happen to be present in the project area during any 
activities related to the Revolution Wind project, they would likely be 
only transient visitors and not engaging in any significant behaviors. 
This very low magnitude and severity of effects is not expected to 
result in impacts on the reproduction or survival of individuals, much 
less impact annual rates of recruitment or survival. For these reasons, 
we have determined, in consideration of all of the effects of the 
Revolution Wind's activities combined, that the take proposed to be 
authorized would have a negligible impact on sperm whales.
Dolphins and Small Whales (Including Delphinids, Pilot Whales, and 
Harbor Porpoises)
    There are no specific issues with the status of odontocete stocks 
that cause particular concern (e.g., no recent UMEs). No mortality or 
serious injury is expected or proposed to be authorized for these 
stocks. Only Level B harassment is anticipated or proposed for 
authorization for any dolphin or small whale.
    The maximum amount of take, by Level B harassment, proposed for 
authorization within any one year for all odontocetes cetacean stocks 
ranges from 15 to 6,229 instances, which is less than a maximum of 3.6 
percent as compared to the population size for all stocks. As described 
above for odontocetes broadly, we anticipate that a fair number of 
these instances of take in a day represent multiple exposures of a 
smaller number of individuals, meaning the actual number of individuals 
taken is lower. Although some amount of repeated exposures to some 
individuals is likely given the duration of activity proposed by 
Revolution Wind, the intensity of any Level B harassment combined with 
the availability of alternate nearby foraging habitat suggests that the 
likely impacts would not impact the reproduction or survival of any 
individuals.
    Overall, the populations of all dolphins and small whale species 
and stocks for which we propose to authorize take are stable (no 
declining population trends), not facing existing UMEs, and the small 
amount, magnitude and severity of effects is not expected to result in 
impacts on the reproduction or survival of any individuals, much less 
affect annual rates of recruitment or survival. For these reasons, we 
have determined, in consideration of all of the effects of the 
Revolution Wind's activities combined, that the take proposed to be 
authorized would have a negligible impact on all dolphin and small 
whale species and stocks considered in this analysis.
Harbor Porpoises
    The Gulf of Maine/Bay of Fundy stock of harbor porpoises is found 
predominantly in northern U.S. coastal waters (less than 150 m depth) 
and up into Canada's Bay of Fundy. Although the population trend is not 
known, there are no UMEs or other factors that cause particular concern 
for this stock. No mortality or non-auditory injury by UXO/MEC 
detonations are anticipated or authorized for this stock. NMFS proposes 
to authorize 49 takes by Level A harassment (PTS; incidental to UXO/MEC 
detonations) and 1,237 takes by Level B harassment (incidental to 
multiple activities).
    Regarding the severity of takes by behavioral Level B harassment, 
because harbor porpoises are particularly sensitive to noise, it is 
likely that a fair

[[Page 79159]]

number of the responses could be of a moderate nature, particularly to 
pile driving. In response to pile driving, harbor porpoises are likely 
to avoid the area during construction, as previously demonstrated in 
Tougaard et al. (2009) in Denmark, in Dahne et al. (2013) in Germany, 
and in Vallejo et al. (2017) in the United Kingdom, although a study by 
Graham et al. (2019) may indicate that the avoidance distance could 
decrease over time. However, pile driving is scheduled to occur when 
harbor porpoise abundance is low off the coast of Rhode Island and, 
given alternative foraging areas, any avoidance of the area by 
individuals is not likely to impact the reproduction or survival of any 
individuals. Given only one UXO/MEC would be detonated on any given day 
and up to only 13 UXO/MEC would be detonated over the 5-year effective 
period of the LOA, any behavioral response would be brief and of a low 
severity.
    With respect to PTS and TTS, the effects on an individual are 
likely relatively low given the frequency bands of pile driving (most 
energy below 2 kHz) compared to harbor porpoise hearing (150 Hz to 160 
kHz peaking around 40 kHz). Specifically, PTS or TTS is unlikely to 
impact hearing ability in their more sensitive hearing ranges, or the 
frequencies in which they communicate and echolocate. Regardless, we 
have authorized a limited amount of PTS, but expect any PTS that may 
occur to be within the very low end of their hearing range where harbor 
porpoises are not particularly sensitive, and any PTS would be of small 
magnitude. As such, any PTS would not interfere with key foraging or 
reproductive strategies necessary for reproduction or survival.
    In summary, the amount of take proposed to be authorized (49 and 
1,237 by Level A harassment and Level B harassment, respectively) is 
small and while harbor porpoises are likely to avoid the area during 
any construction activity discussed herein, as demonstrated during 
European wind farm construction, the time of year in which work would 
occur is when harbor porpoises are not in high abundance, and any work 
that does occur would not result in the species' abandonment of the 
waters off of Rhode Island. The low magnitude and severity of 
harassment effects is not expected to result in impacts on the 
reproduction or survival of any individuals, let alone have impacts on 
annual rates of recruitment or survival of this stock. No mortality or 
serious injury is anticipated or proposed to be authorized. For these 
reasons, we have preliminarily determined, in consideration of all of 
the effects of the Revolution Wind's activities combined, that the 
proposed authorized take would have a negligible impact on the Gulf of 
Maine/Bay of Fundy stock of harbor porpoises.

Pinnipeds (Harbor Seals and Gray Seals)

    Neither the harbor seal nor gray seal are listed under the ESA. 
Revolution Wind requested, and NMFS proposes to authorize that no more 
than 16 and 2,393 harbor seals and 7 and 978 gray seals may be taken by 
Level A harassment and Level B harassment, respectively, within any one 
year. These species occur in Rhode Island waters most often in winter, 
when impact pile driving and UXO/MEC detonations would not occur. Seals 
are also more likely to be close to shore such that exposure to impact 
pile driving would be expected to be at lower levels generally (but 
still above NMFS behavioral harassment threshold). The majority of 
takes of these species is from monopile installations, vibratory pile 
driving associated with temporary cofferdam installation and removal, 
and HRG surveys. Research and observations show that pinnipeds in the 
water may be tolerant of anthropogenic noise and activity (a review of 
behavioral reactions by pinnipeds to impulsive and non-impulsive noise 
can be found in Richardson et al. (1995) and Southall et al. (2007)). 
Available data, though limited, suggest that exposures between 
approximately 90 and 140 dB SPL do not appear to induce strong 
behavioral responses in pinnipeds exposed to non-pulse sounds in water 
(Costa et al., 2003; Jacobs and Terhune, 2002; Kastelein et al., 
2006c). Although there was no significant displacement during 
construction as a whole, Russell et al. (2016) found that displacement 
did occur during active pile driving at predicted received levels 
between 168 and 178 dB re 1[mu]Pa(p-p); however seal 
distribution returned to the pre-piling condition within two hours of 
cessation of pile driving. Pinnipeds may not react at all until the 
sound source is approaching (or they approach the sound source) within 
a few hundred meters and then may alert, ignore the stimulus, change 
their behaviors, or avoid the immediate area by swimming away or 
diving. Effects on pinnipeds that are taken by Level B harassment in 
the project area would likely be limited to reactions such as increased 
swimming speeds, increased surfacing time, or decreased foraging (if 
such activity were occurring). Most likely, individuals would simply 
move away from the sound source and be temporarily displaced from those 
areas (see Lucke et al., 2006; Edren et al., 2010; Skeate et al., 2012; 
Russell et al., 2016). Given their documented tolerance of 
anthropogenic sound (Richardson et al., 1995; Southall et al., 2007), 
repeated exposures of individuals of either of these species to levels 
of sound that may cause Level B harassment are unlikely to 
significantly disrupt foraging behavior. Given the low anticipated 
magnitude of impacts from any given exposure, even repeated Level B 
harassment across a few days of some small subset of individuals, which 
could occur, is unlikely to result in impacts on the reproduction or 
survival of any individuals. Moreover, pinnipeds would benefit from the 
mitigation measures described in the Proposed Mitigation section.
    Revolution Wind requested, and NMFS is proposing to authorize, a 
small amount of PTS (16 harbor seals and 7 gray seals which constitutes 
less than 0.1 percent of each population) incidental to UXO/MEC 
detonation. As described above, noise from UXO/MEC detonation is low 
frequency and, while any PTS that does occur would fall within the 
lower end of pinniped hearing ranges (50 Hz to 86 kHz), PTS would not 
occur at frequencies where pinniped hearing is most sensitive. In 
summary, any PTS, would be of small degree and not occur across the 
entire, or even most sensitive, hearing range. Hence, any impacts from 
PTS are likely to be of low severity and not interfere with behaviors 
critical to reproduction or survival.
    Elevated numbers of harbor seal and gray seal mortalities were 
first observed in July 2018 and occurred across Maine, New Hampshire, 
and Massachusetts until 2020. Based on tests conducted so far, the main 
pathogen found in the seals belonging to that UME was phocine distemper 
virus, although additional testing to identify other factors that may 
be involved in this UME are underway. Currently, the only active UME is 
occurring in Maine with some harbor and gray seals testing positive for 
highly pathogenic avian influenza (HPAI) H5N1. Although elevated 
strandings continue, neither UME (alone or in combination) provide 
cause for concern regarding population-level impacts to any of these 
stocks. For harbor seals, the population abundance is over 75,000 and 
annual M/SI (350) is well below PBR (2,006) (Hayes et al., 2020). The 
population abundance for gray seals in the United States is over 
27,000, with an estimated overall abundance, including seals in Canada, 
of approximately 450,000. In addition, the abundance of gray seals is 
likely

[[Page 79160]]

increasing in the U.S. Atlantic, as well as in Canada (Hayes et al., 
2020).
    Overall, impacts from the Level B harassment take proposed for 
authorization incidental to Revolution Wind's specified activities 
would be of relatively low magnitude and a low severity. Similarly, 
while some individuals may incur PTS overlapping some frequencies that 
are used for foraging and communication, given the low degree, the 
impacts would not be expected to impact reproduction or survival of any 
individuals. In consideration of all of the effects of Revolution 
Wind's activities combined, we have preliminarily determined that the 
authorized take will have a negligible impact on harbor seals and gray 
seals.

Preliminary Negligible Impact Determination

    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 marine mammal 
take from all of Revolution Wind's specified activities combined 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 (by Level A harassment 
and Level B harassment) of 16 species of marine mammal (with 16 managed 
stocks). The maximum number of takes possible within any one year and 
proposed for authorization relative to the best available population 
abundance is low for all species and stocks potentially impacted (i.e., 
less than 1 percent for nine stocks, less than 4 percent for five 
stocks, and less than 12 percent for two stocks; see Table 33). 
Therefore, NMFS preliminarily finds that small numbers of marine 
mammals may be taken relative to the estimated overall population 
abundances for those stocks.
    Based on the analysis contained herein of the proposed action 
(including the proposed mitigation and monitoring measures) and the 
anticipated take of marine mammals, NMFS preliminarily finds that small 
numbers of marine mammals would be taken relative to the population 
size of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

    There are no relevant subsistence uses of the affected marine 
mammal stocks or species implicated by this action. Therefore, NMFS has 
determined that the total taking of affected species or stocks would 
not have an unmitigable adverse impact on the availability of such 
species or stocks for taking for subsistence purposes.

Endangered Species Act (ESA)

    Section 7(a)(2) of the Endangered Species Act of 1973 (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 promulgation of 
rulemakings, NMFS consults internally whenever we propose to authorize 
take for endangered or threatened species, in this case with the NMFS 
Greater Atlantic Regional Field Office (GARFO).
    NMFS is proposing to authorize the take of five marine mammal 
species which are listed under the ESA: the North Atlantic right, sei, 
fin, blue, and sperm whale. The Permit and Conservation Division 
requested initiation of Section 7 consultation on November 1, 2022 with 
GARFO for the issuance of this proposed rulemaking. NMFS will conclude 
the Endangered Species Act consultation prior to reaching a 
determination regarding the proposed issuance of the authorization. The 
proposed regulations and any subsequent LOA(s) would be conditioned 
such that, in addition to measures included in those documents, the 
applicant would also be required to abide by the reasonable and prudent 
measures and terms and conditions of a Biological Opinion and 
Incidental Take Statement, issued by NMFS, pursuant to Section 7 of the 
Endangered Species Act.

Proposed Promulgation

    As a result of these preliminary determinations, NMFS proposes to 
promulgate an ITA for Revolution Wind authorizing take, by Level A and 
B harassment, incidental to construction activities associated with the 
Revolution Wind Offshore Wind Farm project offshore of Rhode Island for 
a 5-year period from October 5, 2023 through October 4, 2028, provided 
the previously mentioned mitigation, monitoring, and reporting 
requirements are incorporated. A draft of the proposed rulemaking can 
be found at https://www.fisheries.noaa.gov/action/incidental-take-authorization-revolution-wind-llc-construction-revolution-wind-energy.

Request for Additional Information and Public Comments

    NMFS requests interested persons to submit comments, information, 
and suggestions concerning Revolution Wind's request and the proposed 
regulations (see ADDRESSES). All comments will be reviewed and 
evaluated as we prepare the final rule and make final determinations on 
whether to issue the requested authorization. This notice and 
referenced documents provide all environmental information relating to 
our proposed action for public review.
    Recognizing, as a general matter, that this action is one of many 
current and future wind energy actions, we invite comment on the 
relative merits of the IHA, single-action rule/LOA, and programmatic 
multi-action rule/LOA approaches, including potential marine mammal 
take impacts resulting from this and other related wind energy actions 
and possible benefits resulting from regulatory certainty and 
efficiency.

Classification

    Pursuant to the procedures established to implement Executive Order 
12866, the Office of Management and Budget has determined that this 
proposed rule is not significant.
    Pursuant to section 605(b) of the Regulatory Flexibility Act (RFA), 
the Chief Counsel for Regulation of the Department of Commerce has 
certified to the Chief Counsel for Advocacy of the Small Business 
Administration that this proposed rule, if adopted, would not have a 
significant economic impact on a substantial number of small entities. 
Revolution Wind is the sole entity that would be subject to the 
requirements in these proposed regulations, and Revolution Wind is not 
a small

[[Page 79161]]

governmental jurisdiction, small organization, or small business, as 
defined by the RFA. Under the RFA, governmental jurisdictions are 
considered to be small if they are governments of cities, counties, 
towns, townships, villages, school districts, or special districts, 
with a population of less than 50,000. Because of this certification, a 
regulatory flexibility analysis is not required and none has been 
prepared.
    Notwithstanding any other provision of law, no person is required 
to respond to nor shall a person be subject to a penalty for failure to 
comply with a collection of information subject to the requirements of 
the Paperwork Reduction Act (PRA) unless that collection of information 
displays a currently valid Office of Management and Budget (OMB) 
control number. These requirements have been approved by OMB under 
control number 0648-0151 and include applications for regulations, 
subsequent LOA, and reports. Send comments regarding any aspect of this 
data collection, including suggestions for reducing the burden, to 
NMFS.
    The Coastal Zone Management Act (CZMA) requires Federal actions 
within and outside the coastal zone that have reasonably foreseeable 
effects on any coastal use or natural resource of the coastal zone be 
consistent with the enforceable policies of a state's federally 
approved coastal management program. 16 U.S.C. 1456(c). Additionally, 
regulations implementing the CZMA require non-Federal applicants for 
Federal licenses or permits to submit a consistency certification to 
the state that declares that the proposed activity complies with the 
enforceable policies of the state's approved management program and 
will be conducted in a manner consistent with such program. As 
required, on June 7, 2021, Revolution Wind submitted a Federal 
consistency certification to the Commonwealth of Massachusetts Office 
of Coastal Zone Management and the State of Rhode Island Coastal 
Resources Management Council for approval of the Construction and 
Operations Plan (COP) by BOEM and the issuance of an Individual Permit 
by United States Army Corps of Engineers, under section 10 and 14 of 
the Rivers and Harbors Act and section 404 of the Clean Water Act (15 
CFR part 930, subpart E). The Commonwealth of Massachusetts issued its 
concurrence on October 7, 2022, and the State of Rhode Island issued 
its concurrence on December 21, 2022.
    NMFS has determined that Revolution Wind's application for an 
authorization to allow the incidental, but not intentional, take of 
small numbers of marine mammals on the outer continental shelf is an 
unlisted activity and, thus, is not, at this time, subject to Federal 
consistency requirements in the absence of the receipt and prior 
approval of an unlisted activity review request from the state by the 
Director of NOAA's Office for Coastal Management.

List of Subjects in 50 CFR Part 217

    Administrative practice and procedure, Endangered and threatened 
species, Exports, Fish, Fisheries, Marine mammals, Penalties, Reporting 
and recordkeeping requirements, Seafood, Transportation, Wildlife.

    Dated: December 14, 2022.
Andrew James Strelcheck
Acting Deputy Assistant Administrator for Regulatory Programs, National 
Marine Fisheries Service.

    For reasons set forth in the preamble, 50 CFR part 217 is proposed 
to be amended as follows:

PART 217--REGULATIONS GOVERNING THE TAKING AND IMPORTING OF MARINE 
MAMMALS

0
1. The authority citation for part 217 continues to read as follows:

    Authority: 16 U.S.C. 1361 et seq., unless otherwise noted.

0
2. Add subpart BB, consisting of Sec. Sec.  217.270 through 217.279, to 
read as follows:
Subpart BB--Taking Marine Mammals Incidental to the Revolution Wind 
Offshore Wind Farm Project Offshore Rhode Island
Sec.
217.270 Specified activity and specified geographical region.
217.271 Effective dates.
217.272 Permissible methods of taking.
217.273 Prohibitions.
217.274 Mitigation requirements.
217.275 Requirements for monitoring and reporting.
217.276 Letter of Authorization.
217.277 Modifications of Letter of Authorization.
217.278-217.279 [Reserved]

Subpart BB--Taking Marine Mammals Incidental to the Revolution Wind 
Offshore Wind Farm Project Offshore Rhode Island


Sec.  217.270  Specified activity and specified geographical region.

    (a) Regulations in this subpart apply only to the taking of marine 
mammals that occurs incidental to activities associated with 
construction of the Revolution Wind Offshore Wind Farm Project by 
Revolution Wind, LLC (Revolution Wind) and those persons it authorizes 
or funds to conduct activities on its behalf in the area outlined in 
paragraph (b) of this section.
    (b) The taking of marine mammals by Revolution Wind may be 
authorized in a Letter of Authorization (LOA) only if it occurs in the 
Bureau of Ocean Energy Management (BOEM) lease area Outer Continental 
Shelf (OCS)-A-0486 Commercial Lease of Submerged Lands for Renewable 
Energy Development and along export cable route at sea-to-shore 
transition points at Quonset Point in North Kingstown, Rhode Island.
    (c) The taking of marine mammals by Revolution Wind is only 
authorized if it occurs incidental to the following activities 
associated with the Revolution Wind Offshore Wind Farm Project:
    (1) Installation of wind turbine generators (WTG) and offshore 
substation (OSS) foundations by impact pile driving;
    (2) Installation of temporary cofferdams by vibratory pile driving;
    (3) High-resolution geophysical (HRG) site characterization 
surveys; and,
    (4) Detonation of unexploded ordnances (UXOs) or munitions and 
explosives of concern (MECs).


Sec.  217.271  Effective dates.

    Regulations in this subpart are effective from October 5, 2023, 
through October 4 31, 2028.


Sec.  217.272  Permissible methods of taking.

    Under an LOA, issued pursuant to Sec. Sec.  216.106 and 217.276, 
Revolution Wind, and those persons it authorizes or funds to conduct 
activities on its behalf, may incidentally, but not intentionally, take 
marine mammals within the area described in Sec.  217.270(b) in the 
following ways, provided Revolution Wind is in complete compliance with 
all terms, conditions, and requirements of the regulations in this 
subpart and the appropriate LOA:
    (a) By Level B harassment associated with the acoustic disturbance 
of marine mammals by impact pile driving (WTG and OSS monopile 
foundation installation), vibratory pile installation and removal of 
temporary cofferdams, the detonation of UXOs/MECs, and through HRG site 
characterization surveys.
    (b) By Level A harassment, provided take is associated with impact 
pile driving and UXO/MEC detonations.
    (c) The incidental take of marine mammals by the activities listed 
in paragraphs (a) and (b) of this section is limited to the following 
species:

[[Page 79162]]



                        Table 1 to Paragraph (c)
------------------------------------------------------------------------
     Marine mammal species         Scientific name           Stock
------------------------------------------------------------------------
Blue whale....................  Balaenoptera musculus  Western North
                                                        Atlantic.
Fin whale.....................  Balaenoptera physalus  Western North
                                                        Atlantic.
Sei whale.....................  Balaenoptera borealis  Nova Scotia.
Minke whale...................  Balaenoptera           Canadian East
                                 acutorostrata.         Stock.
North Atlantic right whale....  Eubalaena glacialis..  Western North
                                                        Atlantic.
Humpback whale................  Megaptera              Gulf of Maine.
                                 novaeangliae.
Sperm whale...................  Physeter               North Atlantic.
                                 macrocephalus.
Atlantic spotted dolphin......  Stenella frontalis...  Western North
                                                        Atlantic.
Atlantic white-sided dolphin..  Lagenorhynchus acutus  Western North
                                                        Atlantic.
Bottlenose dolphin............  Tursiops truncatus...  Western North
                                                        Atlantic
                                                        Offshore.
Common dolphin................  Delphinus delphis....  Western North
                                                        Atlantic.
Harbor porpoise...............  Phocoena phocoena....  Gulf of Maine/Bay
                                                        of Fundy.
Long-finned pilot whale.......  Globicephala melas...  Western North
                                                        Atlantic.
Risso's dolphin...............  Grampus griseus......  Western North
                                                        Atlantic.
Gray seal.....................  Halichoerus grypus...  Western North
                                                        Atlantic.
Harbor seal...................  Phoca vitulina.......  Western North
                                                        Atlantic.
------------------------------------------------------------------------

Sec.  217.273  Prohibitions.

    Except for the takings described in Sec.  217.272 and authorized by 
an LOA issued under Sec.  217.276 or Sec.  217.277, it is unlawful for 
any person to do any of the following in connection with the activities 
described in this subpart:
    (a) Violate, or fail to comply with, the terms, conditions, and 
requirements of this subpart or an LOA issued under Sec. Sec.  217.276 
and 217.277;
    (b) Take any marine mammal not specified in Sec.  217.272(c);
    (c) Take any marine mammal specified in the LOA in any manner other 
than as specified in the LOA; or
    (d) Take any marine mammal, as specified in Sec.  217.272(c), after 
NMFS determines such taking results in more than a negligible impact on 
the species or stocks of such marine mammals.


Sec.  217.274  Mitigation requirements.

    When conducting the activities identified in Sec. Sec.  217.270(a) 
and 217.272, Revolution Wind must implement the mitigation measures 
contained in this section and any LOA issued under Sec.  217.276 or 
Sec.  217.277. These mitigation measures must include, but are not 
limited to:
    (a) General conditions. (1) A copy of any issued LOA must be in the 
possession of Revolution Wind and its designees, all vessel operators, 
visual protected species observers (PSOs), passive acoustic monitoring 
(PAM) operators, pile driver operators, and any other relevant 
designees operating under the authority of the issued LOA;
    (2) Revolution Wind must conduct briefings between construction 
supervisors, construction crews, and the PSO and PAM team prior to the 
start of all construction activities, and when new personnel join the 
work, in order to explain responsibilities, communication procedures, 
marine mammal monitoring and reporting protocols, and operational 
procedures. An informal guide must be included with the Marine Mammal 
Monitoring Plan to aid personnel in identifying species if they are 
observed in the vicinity of the project area;
    (3) Revolution Wind must instruct all vessel personnel regarding 
the authority of the PSO(s). For example, the vessel operator(s) would 
be required to immediately comply with any call for a shutdown by the 
Lead PSO. Any disagreement between the Lead PSO and the vessel operator 
would only be discussed after shutdown has occurred;
    (4) Revolution Wind must ensure that any visual observations of an 
ESA-listed marine mammal are communicated to PSOs and vessel captains 
during the concurrent use of multiple project-associated vessels (of 
any size; e.g., construction surveys, crew/supply transfers, etc.);
    (5) If an individual from a species for which authorization has not 
been granted, or a species for which authorization has been granted but 
the authorized take number has been met, is observed entering or within 
the relevant Level B harassment zone for each specified activity, pile 
driving and pneumatic hammering activities, and HRG acoustic sources 
must be shut down immediately, unless shutdown is not practicable, or 
be delayed if the activity has not commenced. Impact and vibratory pile 
driving, pneumatic hammering, UXO/MEC detonation, and initiation of HRG 
acoustic sources must not commence or resume until the animal(s) has 
been confirmed to have left the relevant clearance zone or the 
observation time has elapsed with no further sightings. UXO/MEC 
detonations may not occur until the animal(s) has been confirmed to 
have left the relevant clearance zone or the observation time has 
elapsed with no further sightings;
    (6) Prior to and when conducting any in-water construction 
activities and vessel operations, Revolution Wind personnel (e.g., 
vessel operators, PSOs) must use available sources of information on 
North Atlantic right whale presence in or near the project area 
including daily monitoring of the Right Whale Sightings Advisory 
System, and monitoring of Coast Guard VHF Channel 16 throughout the day 
to receive notification of any sightings and/or information associated 
with any slow zones (i.e., Dynamic Management Areas (DMAs) and/or 
acoustically-triggered slow zones) to provide situational awareness for 
both vessel operators and PSOs; and
    (7) Any marine mammals observed within a clearance or shutdown zone 
must be allowed to remain in the area (i.e., must leave of their own 
volition) prior to commencing impact and vibratory pile driving 
activities, pneumatic hammering, or HRG surveys.
    (8) Revolution Wind must treat any large whale sighted by a PSO or 
acoustically detected by a PAM operator as if it were a North Atlantic 
right whale, unless a PSO or a PAM operator confirms it is another type 
of whale.
    (b) Vessel strike avoidance measures. (1) Prior to the start of 
construction activities, all vessel operators and crew must receive a 
protected species identification training that covers, at a minimum:
    (i) Sightings of marine mammals and other protected species known 
to occur or which have the potential to occur in the Revolution Wind 
project area;
    (ii) Training on making observations in both good weather 
conditions (i.e., clear visibility, low winds, low sea states) and bad 
weather conditions (i.e.,

[[Page 79163]]

fog, high winds, high sea states, with glare);
    (iii) Training on information and resources available to the 
project personnel regarding the applicability of Federal laws and 
regulations for protected species;
    (iv) Observer training related to these vessel strike avoidance 
measures must be conducted for all vessel operators and crew prior to 
the start of in-water construction activities; and
    (v) Confirmation of marine mammal observer training (including an 
understanding of the LOA requirements) must be documented on a training 
course log sheet and reported to NMFS.
    (2) All vessels must abide by the following:
    (i) All vessel operators and crews, regardless of their vessel's 
size, must maintain a vigilant watch for all marine mammals and slow 
down, stop their vessel, or alter course, as appropriate, to avoid 
striking any marine mammal;
    (ii) All vessels must have a visual observer on board who is 
responsible for monitoring the vessel strike avoidance zone for marine 
mammals. Visual observers may be PSO or crew members, but crew members 
responsible for these duties must be provided sufficient training by 
Revolution Wind to distinguish marine mammals from other phenomena and 
must be able to identify a marine mammal as a North Atlantic right 
whale, other whale (defined in this context as sperm whales or baleen 
whales other than North Atlantic right whales), or other marine mammal. 
Crew members serving as visual observers must not have duties other 
than observing for marine mammals while the vessel is operating over 10 
knots (kns);
    (iii) Year-round and when a vessel is in transit, all vessel 
operators must continuously monitor U.S. Coast Guard VHF Channel 16, 
over which North Atlantic right whale sightings are broadcasted. At the 
onset of transiting and at least once every four hours, vessel 
operators and/or trained crew members must monitor the project's 
Situational Awareness System, WhaleAlert, and the Right Whale Sighting 
Advisory System (RWSAS) for the presence of North Atlantic right whales 
Any observations of any large whale by any Revolution Wind staff or 
contractors, including vessel crew, must be communicated immediately to 
PSOs, PAM operator, and all vessel captains to increase situational 
awareness. Conversely, any large whale observation or detection via a 
sighting network (e.g., Mysticetus) by PSOs or PAM operators must be 
conveyed to vessel operators and crew;
    (iv) Any observations of any large whale by any Revolution Wind 
staff or contractor, including vessel crew, must be communicated 
immediately to PSOs and all vessel captains to increase situational 
awareness;
    (v) All vessels must comply with existing NMFS vessel speed 
regulations in 50 CFR 224.105, as applicable, for North Atlantic right 
whales;
    (vi) In the event that any slow zone (designated as a DMA) is 
established that overlaps with an area where a project-associated 
vessel would operate, that vessel, regardless of size, will transit 
that area at 10 kns or less;
    (vii) Between November 1st and April 30th, all vessels, regardless 
of size, would operate port to port (specifically from ports in New 
Jersey, New York, Maryland, Delaware, and Virginia) at 10 kns or less, 
except for vessels while transiting in Narragansett Bay or Long Island 
Sound which have not been demonstrated by best available science to 
provide consistent habitat for North Atlantic right whales;
    (viii) All vessels, regardless of size, must immediately reduce 
speed to 10 kns or less when any large whale, mother/calf pairs, or 
large assemblages of non-delphinid cetaceans are observed (within 500 
m) of an underway vessel;
    (ix) All vessels, regardless of size, must immediately reduce speed 
to 10 kns or less when a North Atlantic right whale is sighted, at any 
distance, by anyone on the vessel;
    (x) If a vessel is traveling at greater than 10 kns, in addition to 
the required dedicated visual observer, Revolution Wind must monitor 
the transit corridor in real-time with PAM prior to and during 
transits. If a North Atlantic right whale is detected via visual 
observation or PAM within or approaching the transit corridor, all crew 
transfer vessels must travel at 10 kns or less for 12 hours following 
the detection. Each subsequent detection triggers an additional 12-hour 
period at 10 kns or less. A slowdown in the transit corridor expires 
when there has been no further visual or acoustic detection of North 
Atlantic right whales in the transit corridor for 12 hours;
    (xi) All underway vessels (e.g., transiting, surveying) operating 
at any speed must have a dedicated visual observer on duty at all times 
to monitor for marine mammals within a 180[deg] direction of the 
forward path of the vessel (90[deg] port to 90[deg] starboard) located 
at an appropriate vantage point for ensuring vessels are maintaining 
appropriate separation distances. Visual observers must be equipped 
with alternative monitoring technology for periods of low visibility 
(e.g., darkness, rain, fog, etc.). The dedicated visual observer must 
receive prior training on protected species detection and 
identification, vessel strike minimization procedures, how and when to 
communicate with the vessel captain, and reporting requirements in this 
proposed action. Visual observers may be third-party observers (i.e., 
NMFS-approved PSOs) or crew members. Observer training related to these 
vessel strike avoidance measures must be conducted for all vessel 
operators and crew prior to the start of in-water construction 
activities;
    (xii) All vessels must maintain a minimum separation distance of 
500 m from North Atlantic right whales. If underway, all vessels must 
steer a course away from any sighted North Atlantic right whale at 10 
kns or less such that the 500-m minimum separation distance requirement 
is not violated. If a North Atlantic right whale is sighted within 500 
m of an underway vessel, that vessel must shift the engine to neutral. 
Engines must not be engaged until the whale has moved outside of the 
vessel's path and beyond 500 m. If a whale is observed but cannot be 
confirmed as a species other than a North Atlantic right whale, the 
vessel operator must assume that it is a North Atlantic right whale and 
take the vessel strike avoidance measures described in this paragraph 
(b)(2)(xii);
    (xiii) All vessels must maintain a minimum separation distance of 
100 m from sperm whales and baleen whales other than North Atlantic 
right whales. If one of these species is sighted within 100 m of an 
underway vessel, that vessel must shift the engine to neutral. Engines 
must not be engaged until the whale has moved outside of the vessel's 
path and beyond 100 m;
    (xiv) All vessels must, to the maximum extent practicable, attempt 
to maintain a minimum separation distance of 50 m from all delphinoid 
cetaceans and pinnipeds, with an exception made for those that approach 
the vessel (e.g., bow-riding dolphins). If a delphinid cetacean or 
pinniped is sighted within 50 m of an underway vessel, that vessel must 
shift the engine to neutral, with an exception made for those that 
approach the vessel (e.g., bow-riding dolphins). Engines must not be 
engaged until the animal(s) has moved outside of the vessel's path and 
beyond 50 m;
    (xv) When a marine mammal(s) is sighted while a vessel is underway, 
the vessel must take action as necessary to avoid violating the 
relevant separation distances (e.g., attempt to remain parallel to the 
animal's course, avoid excessive speed or abrupt changes in

[[Page 79164]]

direction until the animal has left the area). If a marine mammal(s) is 
sighted within the relevant separation distance, the vessel must reduce 
speed and shift the engine to neutral, not engaging the engine(s) until 
the animal(s) is clear of the area. This does not apply to any vessel 
towing gear or any situation where respecting the relevant separation 
distance would be unsafe (i.e., any situation where the vessel is 
navigationally constrained);
    (xvi) All vessels underway must not divert or alter course to 
approach any marine mammal. Any vessel underway must avoid speed over 
10 kns or abrupt changes in course direction until the animal is out of 
an on a path away from the separation distances;
    (xvii) For in-water construction heavy machinery activities other 
than impact or vibratory pile driving, if a marine mammal is on a path 
towards or comes within 10 m of equipment, Revolution Wind must cease 
operations until the marine mammal has moved more than 10 m on a path 
away from the activity to avoid direct interaction with equipment; and
    (xviii) Revolution Wind must submit a North Atlantic right whale 
vessel strike avoidance plan 90 days prior to commencement of vessel 
use. The plan will, at minimum, describe how PAM, in combination with 
visual observations, will be conducted to ensure the transit corridor 
is clear of right whales. The plan will also provide details on the 
vessel-based observer protocols on transiting vessels.
    (c) Fisheries monitoring surveys--(1) Training. (i) All crew 
undertaking the fishery survey activities must receive protected 
species identification training prior to activities occurring.
    (ii) [Reserved]
    (2) During vessel use. (i) Marine mammal monitoring must occur 
prior to, during, and after haul-back, and gear must not be deployed if 
a marine mammal is observed in the area;
    (ii) Trawl operations must only start after 15 minutes of no marine 
mammal sightings within 1 nautical mile (nmi) of the sampling station; 
and
    (iii) During daytime sampling for the research trawl surveys, 
Revolution Wind must maintain visual monitoring efforts during the 
entire period of time that trawl gear is in the water from deployment 
to retrieval. If a marine mammal is sighted before the gear is removed 
from the water, the vessel must slow its speed and steer away from the 
observed animal(s).
    (3) Gear-specific best management practices (BMPs). (i) Research 
trawl bottom times must be limited to 20 minutes;
    (ii) Ventless trap surveys must utilize sinking ground lines and 
all lines will have breaking strength of less than 1,700 pounds and 
sinking groundlines. Sampling gear must be hauled at least once every 
30 days, and the gear must be removed from the water at the end of each 
sampling season;
    (iii) The permit number must be written clearly on buoy and any 
lines that go missing must be reported to NOAA Fisheries' Greater 
Atlantic Regional Fisheries Office (GARFO) Protected Resources Division 
as soon as possible;
    (iv) If marine mammals are sighted near the proposed sampling 
location, trawl or ventless trap gear must be delayed until the marine 
mammal(s) has left the area;
    (v) If a marine mammal is determined to be at risk of interaction 
with the deployed gear, all gear must be immediately removed;
    (vi) Marine mammal monitoring must occur during daylight hours and 
begin prior to the deployment of any gear (e.g., trawls) and continue 
until all gear has been retrieved; and
    (vii) If marine mammals are sighted in the vicinity within 15 
minutes prior to gear deployment and it is determined the risks of 
interaction are present regarding the research gear, the sampling 
station must either be moved to another location or activities must be 
suspended until there are no marine mammal sightings for 15 minutes 
within 1 nm.
    (d) Wind turbine generator (WTG) and offshore substation (OSS) 
foundation installation--(1) Seasonal and daily restrictions. (i) 
Foundation impact pile driving activities may not occur January 1 
through April 30;
    (ii) No more than three foundation monopiles may be installed per 
day;
    (iii) Revolution Wind must not initiate pile driving earlier than 1 
hour after civil sunrise or later than 1.5 hours prior to civil sunset, 
unless Revolution Wind submits and NMFS approves an Alternative 
Monitoring Plan as part of the Pile Driving and Marine Mammal 
Monitoring Plan that reliably demonstrates the efficacy of their night 
vision devices; and
    (iv) Monopiles must be no larger than 15 m in diameter, 
representing the larger end of the tapered 7/15 m monopile design. The 
minimum amount of hammer energy necessary to effectively and safely 
install and maintain the integrity of the piles must be used. Maximum 
hammer energies must not exceed 4,000 kilojoules (kJ).
    (2) Noise abatement systems. (i) Revolution Wind must deploy dual 
noise abatement systems that are capable of achieving, at a minimum, 
10-dB of sound attenuation, during all impact pile driving of 
foundation piles:
    (A) A single big bubble curtain (BBC) must not be used unless 
paired with another noise attenuation device; and
    (B) A double big bubble curtain (dBBC) may be used without being 
paired with another noise attenuation device;
    (ii) The bubble curtain(s) must distribute air bubbles using an air 
flow rate of at least 0.5 m\3\/(min*m). The bubble curtain(s) must 
surround 100 percent of the piling perimeter throughout the full depth 
of the water column. In the unforeseen event of a single compressor 
malfunction, the offshore personnel operating the bubble curtain(s) 
must make appropriate adjustments to the air supply and operating 
pressure such that the maximum possible sound attenuation performance 
of the bubble curtain(s) is achieved;
    (iii) The lowest bubble ring must be in contact with the seafloor 
for the full circumference of the ring, and the weights attached to the 
bottom ring must ensure 100-percent seafloor contact;
    (iv) No parts of the ring or other objects may prevent full 
seafloor contact; and
    (v) Construction contractors must train personnel in the proper 
balancing of airflow to the ring. Construction contractors must submit 
an inspection/performance report for approval by Revolution Wind within 
72 hours following the performance test. Corrections to the bubble 
ring(s) to meet the performance standards in this paragraph (d)(2) must 
occur prior to impact pile driving of monopiles. If Revolution Wind 
uses a noise mitigation device in addition to the BBC, Revolution Wind 
must maintain similar quality control measures as described in this 
paragraph (d)(2).
    (3) Sound field verification. (i) Revolution Wind must perform 
sound field verification (SFV) during all impact pile driving of the 
first three monopiles and must empirically determine source levels 
(peak and cumulative sound exposure level), the ranges to the isopleths 
corresponding to the Level A harassment (permanent threshold shift 
(PTS)) and Level B harassment thresholds, and estimated transmission 
loss coefficients;
    (ii) If a subsequent monopile installation location is selected 
that was not represented by previous three locations (i.e., substrate 
composition, water depth), SFV must be conducted;
    (iii) Revolution Wind may estimate ranges to the Level A harassment 
and

[[Page 79165]]

Level B harassment isopleths by extrapolating from in situ measurements 
conducted at several distances from the monopiles, and must measure 
received levels at a standard distance of 750 m from the monopiles;
    (iv) If SFV measurements on any of the first three piles indicate 
that the ranges to Level A harassment and Level B harassment isopleths 
are larger than those modeled, assuming 10-dB attenuation, Revolution 
Wind must modify and/or apply additional noise attenuation measures 
(e.g., improve efficiency of bubble curtain(s), modify the piling 
schedule to reduce the source sound, install an additional noise 
attenuation device) before the second pile is installed. Until SFV 
confirms the ranges to Level A harassment and Level B harassment 
isopleths are less than or equal to those modeled, assuming 10-dB 
attenuation, the shutdown and clearance zones must be expanded to match 
the ranges to the Level A harassment and Level B harassment isopleths 
based on the SFV measurements. If the application/use of additional 
noise attenuation measures still does not achieve ranges less than or 
equal to those modeled, assuming 10-dB attenuation, and no other 
actions can further reduce sound levels, Revolution Wind must expand 
the clearance and shutdown zones according to those identified through 
SFV, in consultation with NMFS;
    (v) If harassment zones are expanded beyond an additional 1,500 m, 
additional PSOs must be deployed on additional platforms, with each 
observer responsible for maintaining watch in no more than 180[deg] and 
of an area with a radius no greater than 1,500 m;
    (vi) If acoustic measurements indicate that ranges to isopleths 
corresponding to the Level A harassment and Level B harassment 
thresholds are less than the ranges predicted by modeling (assuming 10-
dB attenuation), Revolution Wind may request a modification of the 
clearance and shutdown zones for impact pile driving of monopiles and 
UXO/MEC detonations. For a modification request to be considered by 
NMFS, Revolution Wind must have conducted SFV on three or more 
monopiles and on all detonated UXOs/MECs thus far to verify that zone 
sizes are consistently smaller than predicted by modeling (assuming 10-
dB attenuation). Regardless of SFV measurements, the clearance and 
shutdown zones for North Atlantic right whales must not be decreased;
    (vii) If a subsequent monopile installation location is selected 
that was not represented by previous locations (i.e., substrate 
composition, water depth), SFV must be conducted. If a subsequent UXO/
MEC charge weight is encountered and/or detonation location is selected 
that was not representative of the previous locations (i.e., substrate 
composition, water depth), SFV must be conducted;
    (viii) Revolution Wind must submit a SFV Plan at least 180 days 
prior to the planned start of impact pile driving and any UXO/MEC 
detonation activities. The plan must describe how Revolution Wind would 
ensure that the first three monopile foundation installation sites 
selected and each UXO/MEC detonation scenario (i.e., charge weight, 
location) selected for SFV are representative of the rest of the 
monopile installation sites and UXO/MEC scenarios. In the case that 
these sites/scenarios are not determined to be representative of all 
other monopile installation sites and UXO/MEC detonations, Revolution 
Wind must include information on how additional sites/scenarios would 
be selected for SFV. The plan must also include methodology for 
collecting, analyzing, and preparing SFV data for submission to NMFS. 
The plan must describe how the effectiveness of the sound attenuation 
methodology would be evaluated based on the results. Revolution Wind 
must also provide, as soon as they are available but no later than 48 
hours after each installation, the initial results of the SFV 
measurements to NMFS in an interim report after each monopile for the 
first three piles and after each UXO/MEC detonation; and
    (ix) The SFV plan must also include how operational noise would be 
monitored. Revolution Wind must estimate source levels (at 10 m from 
the operating foundation) based on received levels measured at 50 m, 
100 m, and 250 m from the pile foundation. These data must be used to 
identify estimated transmission loss rates. Operational parameters 
(e.g., direct drive/gearbox information, turbine rotation rate) as well 
as sea state conditions and information on nearby anthropogenic 
activities (e.g., vessels transiting or operating in the area) must be 
reported.
    (4) Protected species observer and passive acoustic monitoring use. 
(i) Revolution Wind must have a minimum of four PSOs actively observing 
marine mammals before, during, and after (specific times described in 
this paragraph (d)(4)) the installation of monopiles. At least four 
PSOs must be actively observing for marine mammals. At least two PSOs 
must be actively observing on the pile driving vessel while at least 
two PSOs must be actively observing on a secondary, PSO-dedicated 
vessel. At least one active PSO on each platform must have a minimum of 
90 days at-sea experience working in those roles in offshore 
environments with no more than eighteen months elapsed since the 
conclusion of the at-sea experience. Concurrently, at least one 
acoustic PSO (i.e., passive acoustic monitoring (PAM) operator) must be 
actively monitoring for marine mammals before, during and after impact 
pile driving with PAM; and
    (ii) All visual PSOs and PAM operators used for the Revolution Wind 
project must meet the requirements and qualifications described in 
Sec.  217.275(a) and (b), and (c), respectively, and as applicable to 
the specified activity.
    (5) Clearance and shutdown zones. (i) Revolution Wind must 
establish and implement clearance and shutdown zones (all distances to 
the perimeter are the radii from the center of the pile being driven) 
as described in the LOA for all WTG and OSS foundation installation;
    (ii) Revolution Wind must use visual PSOs and PAM operators to 
monitor the area around each foundation pile before, during and after 
pile driving. PSOs must visually monitor clearance zones for marine 
mammals for a minimum of 60 minutes prior to commencing pile driving. 
At least one PAM operator must review data from at least 24 hours prior 
to pile driving and actively monitor hydrophones for 60 minutes prior 
to pile driving. Prior to initiating soft-start procedures, all 
clearance zones must be visually confirmed to be free of marine mammals 
for 30 minutes immediately prior to starting a soft-start of pile 
driving;
    (iii) PSOs must be able to visually clear (i.e., confirm no marine 
mammals are present) an area that extends around the pile being driven 
as described in the LOA. The entire minimum visibility zone must be 
visible (i.e., not obscured by dark, rain, fog, etc.) for a full 30 
minutes immediately prior to commencing impact pile driving (minimum 
visibility zone size dependent on season);
    (iv) If a marine mammal is observed entering or within the relevant 
clearance zone prior to the initiation of impact pile driving 
activities, pile driving must be delayed and must not begin until 
either the marine mammal(s) has voluntarily left the specific clearance 
zones and have been visually or acoustically confirmed beyond that 
clearance zone, or, when specific time periods have elapsed with no 
further sightings or acoustic detections. The specific time periods are 
15 minutes for small odontocetes and 30 minutes for all other marine 
mammal species;
    (v) The clearance zone may only be declared clear if no confirmed 
North

[[Page 79166]]

Atlantic right whale acoustic detections (in addition to visual) have 
occurred within the PAM clearance zone during the 60-minute monitoring 
period. Any large whale sighting by a PSO or detected by a PAM operator 
that cannot be identified by species must be treated as if it were a 
North Atlantic right whale;
    (vi) If a marine mammal is observed entering or within the 
respective shutdown zone, as defined in the LOA, after impact pile 
driving has begun, the PSO must call for a temporary shutdown of impact 
pile driving;
    (vii) Revolution Wind must immediately cease pile driving if a PSO 
calls for shutdown, unless shutdown is not practicable due to imminent 
risk of injury or loss of life to an individual, pile refusal, or pile 
instability. In this situation, Revolution Wind must reduce hammer 
energy to the lowest level practicable;
    (viii) Pile driving must not restart until either the marine 
mammal(s) has voluntarily left the specific clearance zones and has 
been visually or acoustically confirmed beyond that clearance zone, or, 
when specific time periods have elapsed with no further sightings or 
acoustic detections have occurred. The specific time periods are 15 
minutes for small odontocetes and 30 minutes for all other marine 
mammal species. In cases where these criteria are not met, pile driving 
may restart only if necessary to maintain pile stability at which time 
Revolution Wind must use the lowest hammer energy practicable to 
maintain stability;
    (ix) If impact pile driving has been shut down due to the presence 
of a North Atlantic right whale, pile driving may not restart until the 
North Atlantic right whale is no longer observed or 30 minutes has 
elapsed since the last detection; and
    (x) Upon re-starting pile driving, soft start protocols must be 
followed.
    (6) Soft start. (i) Revolution Wind must utilize a soft start 
protocol for impact pile driving of monopiles by performing 4-6 strikes 
per minute at 10 to 20 percent of the maximum hammer energy, for a 
minimum of 20 minutes;
    (ii) Soft start must occur at the beginning of monopile 
installation and at any time following a cessation of impact pile 
driving of 30 minutes or longer; and
    (iii) If a marine mammal is detected within or about to enter the 
applicable clearance zones, prior to the beginning of soft-start 
procedures, impact pile driving must be delayed until the animal has 
been visually observed exiting the clearance zone or until a specific 
time period has elapsed with no further sightings. The specific time 
periods are 15 minutes for small odontocetes and 30 minutes for all 
other species.
    (e) Cofferdam or casing pipe installation--(1) Daily restrictions. 
(i) Revolution Wind must conduct vibratory pile driving or pneumatic 
hammering during daylight hours only.
    (ii) [Reserved]
    (2) PSO use. (i) All visual PSOs used for the Revolution Wind 
project must meet the requirements and qualifications described in 
Sec.  217.275(a) and (b), as applicable to the specified activity; and
    (ii) Revolution Wind must have a minimum of two PSOs on active duty 
during any installation and removal of the temporary cofferdams, or 
casing pipes and goal posts. These PSOs would always be located at the 
best vantage point(s) on the vibratory pile driving platform or 
secondary platform in the immediate vicinity of the vibratory pile 
driving platform, in order to ensure that appropriate visual coverage 
is available for the entire visual clearance zone and as much of the 
Level B harassment zone, as possible.
    (3) Clearance and shutdown zones. (i) Revolution Wind must 
establish and implement clearance and shutdown zones as described in 
the LOA;
    (ii) Prior to the start of pneumatic hammering or vibratory pile 
driving activities, at least two PSOs must monitor the clearance zone 
for 30 minutes, continue monitoring during pile driving and for 30 
minutes post pile driving;
    (iii) If a marine mammal is observed entering or is observed within 
the clearance zones, piling and hammering must not commence until the 
animal has exited the zone or a specific amount of time has elapsed 
since the last sighting. The specific amount of time is 30 minutes for 
large whales and 15 minutes for dolphins, porpoises, and pinnipeds;
    (iv) If a marine mammal is observed entering or within the 
respective shutdown zone, as defined in the LOA, after vibratory pile 
driving or hammering has begun, the PSO must call for a temporary 
shutdown of vibratory pile driving or hammering;
    (v) Revolution Wind must immediately cease pile driving or 
pneumatic hammering if a PSO calls for shutdown, unless shutdown is not 
practicable due to imminent risk of injury or loss of life to an 
individual, pile refusal, or pile instability; and
    (vi) Pile driving must not restart until either the marine 
mammal(s) has voluntarily left the specific clearance zones and have 
been visually or acoustically confirmed beyond that clearance zone, or, 
when specific time periods have elapsed with no further sightings or 
acoustic detections have occurred. The specific time periods are 15 
minutes for small odontocetes and 30 minutes for all other marine 
mammal species.
    (f) UXO/MEC detonation--(1) General. (i) Revolution Wind shall only 
detonate a maximum of 13 UXO/MECs, of varying sizes;
    (ii) Upon encountering a UXO/MEC of concern, Revolution Wind may 
only resort to high-order removal (i.e., detonation) if all other means 
of removal are impracticable; and
    (iii) Revolution Wind must utilize a noise abatement system (e.g., 
bubble curtain or similar noise abatement device) around all UXO/MEC 
detonations and operate that system in a manner that achieves the 
maximum noise attenuation levels practicable.
    (2) Seasonal and daily restrictions. (i) Revolution Wind must not 
detonate UXOs/MECs from December 1 through April 31, annually; and
    (ii) Revolution Wind must only detonate UXO/MECs during daylight 
hours.
    (3) PSO and PAM use. (i) All visual PSOs and PAM operators used for 
the Revolution Wind project must meet the requirements and 
qualifications described in Sec.  217.265(a) and (b), and (c), 
respectively, and as applicable to the specified activity; and
    (ii) Revolution Wind must use at least 2 visual PSOs on each 
platform (i.e., vessels, plane) and one acoustic PSO to monitor for 
marine mammals in the clearance zones prior to detonation. If the 
clearance zone is larger than 2 km (based on charge weight), Revolution 
Wind must deploy a secondary PSO vessel. If the clearance is larger 
than 5 km (based on charge weight), an aerial survey must be conducted.
    (4) Clearance zones. (i) Revolution Wind must establish and 
implement clearance zones using both visual and acoustic monitoring, as 
described in the LOA;
    (ii) Clearance zones must be fully visible for at least 60 minutes 
and all marine mammal(s) must be confirmed to be outside of the 
clearance zone for at least 30 minutes prior to detonation. PAM must 
also be conducted for at least 60 minutes prior to detonation and the 
zone must be acoustically cleared during this time; and
    (iii) If a marine mammal is observed entering or within the 
clearance zone prior to denotation, the activity must be delayed. 
Detonation may only commence if all marine mammals have been confirmed 
to have voluntarily left

[[Page 79167]]

the clearance zones and been visually confirmed to be beyond the 
clearance zone, or when 60 minutes have elapsed without any 
redetections for whales (including the North Atlantic right whale) or 
15 minutes have elapsed without any redetections of delphinids, harbor 
porpoises, or seals.
    (5) Sound field verification. (i) During each UXO/MEC detonation, 
Revolution Wind must empirically determine source levels (peak and 
cumulative sound exposure level), the ranges to the isopleths 
corresponding to the Level A harassment and Level B harassment 
thresholds, and estimated transmission loss coefficient(s); and
    (ii) If SFV measurements on any of the detonations indicate that 
the ranges to Level A harassment and Level B harassment thresholds are 
larger than those modeled, assuming 10-dB attenuation, Revolution Wind 
must modify the ranges, with approval from NMFS, and/or apply 
additional noise attenuation measures (e.g., improve efficiency of 
bubble curtain(s), install an additional noise attenuation device) 
before the next detonation event.
    (g) HRG surveys--(1) General. (i) All personnel with 
responsibilities for marine mammal monitoring must participate in 
joint, onboard briefings that would be led by the vessel operator and 
the Lead PSO, prior to the beginning of survey activities. The briefing 
must be repeated whenever new relevant personnel (e.g., new PSOs, 
acoustic source operators, relevant crew) join the survey operation 
before work commences;
    (ii) Revolution Wind must deactivate acoustic sources during 
periods where no data is being collected, except as determined to be 
necessary for testing. Unnecessary use of the acoustic source(s) is 
prohibited; and
    (iii) Any large whale sighted by a PSO within 1 km of the boomer, 
sparker, or compressed high-intensity radiated pulse (CHIRP) that 
cannot be identified by species must be treated as if it were a North 
Atlantic right whale.
    (2) PSO use. (i) Revolution Wind must use at least one PSO during 
daylight hours and two PSOs during nighttime operations, per vessel;
    (ii) PSOs must establish and monitor the appropriate clearance and 
shutdown zones (i.e., radial distances from the acoustic source in-use 
and not from the vessel); and
    (iii) PSOs must begin visually monitoring 30 minutes prior to the 
initiation of the specified acoustic source (i.e., ramp-up, if 
applicable), through 30 minutes after the use of the specified acoustic 
source has ceased.
    (3) Ramp-up. (i) Any ramp-up activities of boomers, sparkers, and 
CHIRPs must only commence when visual clearance zones are fully visible 
(e.g., not obscured by darkness, rain, fog, etc.) and clear of marine 
mammals, as determined by the Lead PSO, for at least 30 minutes 
immediately prior to the initiation of survey activities using a 
specified acoustic source;
    (ii) Prior to a ramp-up procedure starting, the operator must 
notify the Lead PSO of the planned start of the ramp-up. This 
notification time must not be less than 60 minutes prior to the planned 
ramp-up activities as all relevant PSOs must monitor the clearance zone 
for 30 minutes prior to the initiation of ramp-up; and
    (iii) Prior to starting the survey and after receiving confirmation 
from the PSOs that the clearance zone is clear of any marine mammals, 
Revolution Wind must ramp-up sources to half power for 5 minutes and 
then proceed to full power, unless the source operates on a binary on/
off switch in which case ramp-up is not feasible. Ramp-up activities 
would be delayed if a marine mammal(s) enters its respective shutdown 
zone. Ramp-up would only be reinitiated if the animal(s) has been 
observed exiting its respective shutdown zone or until additional time 
has elapsed with no further sighting. The specific time periods are 15 
minutes for small odontocetes and seals, and 30 minutes for all other 
species.
    (4) Clearance and shutdown zones. (i) Revolution Wind must 
establish and implement clearance zones as described in the LOA;
    (ii) Revolution Wind must implement a 30 minute clearance period of 
the clearance zones immediately prior to the commencing of the survey 
or when there is more than a 30 minute break in survey activities and 
PSOs are not actively monitoring;
    (iii) If a marine mammal is observed within a clearance zone during 
the clearance period, ramp-up would not be allowed to begin until the 
animal(s) has been observed voluntarily exiting its respective 
clearance zone or until a specific time period has elapsed with no 
further sighting. The specific time period is 15 minutes for small 
odontocetes and seals, and 30 minutes for all other species;
    (iv) In any case when the clearance process has begun in conditions 
with good visibility, including via the use of night vision equipment 
(IR/thermal camera), and the Lead PSO has determined that the clearance 
zones are clear of marine mammals, survey operations would be allowed 
to commence (i.e., no delay is required) despite periods of inclement 
weather and/or loss of daylight;
    (v) Once the survey has commenced, Revolution Wind must shut down 
boomers, sparkers, and CHIRPs if a marine mammal enters a respective 
shutdown zone;
    (vi) In cases when the shutdown zones become obscured for brief 
periods due to inclement weather, survey operations would be allowed to 
continue (i.e., no shutdown is required) so long as no marine mammals 
have been detected;
    (vii) The use of boomers, and sparkers, and CHIRPS would not be 
allowed to commence or resume until the animal(s) has been confirmed to 
have left the Level B harassment zone or until a full 15 minutes (for 
small odontocetes and seals) or 30 minutes (for all other marine 
mammals) have elapsed with no further sighting;
    (viii) Revolution Wind must immediately shutdown any boomer, 
sparker, or CHIRP acoustic source if a marine mammal is sighted 
entering or within its respective shutdown zones. The shutdown 
requirement in this paragraph (g)(4)(viii) does not apply to small 
delphinids of the following genera: Delphinus, Stenella, 
Lagenorhynchus, and Tursiops. If there is uncertainty regarding the 
identification of a marine mammal species (i.e., whether the observed 
marine mammal belongs to one of the delphinid genera for which shutdown 
is waived), the PSOs must use their best professional judgment in 
making the decision to call for a shutdown. Shutdown is required if a 
delphinid that belongs to a genus other than those specified here is 
detected in the shutdown zone;
    (ix) If a boomer, sparker, or CHIRP is shut down for reasons other 
than mitigation (e.g., mechanical difficulty) for less than 30 minutes, 
it would be allowed to be activated again without ramp-up only if:
    (A) PSOs have maintained constant observation; and
    (B) No additional detections of any marine mammal occurred within 
the respective shutdown zones; and
    (x) If a boomer, sparker, or CHIRP was shut down for a period 
longer than 30 minutes, then all clearance and ramp-up procedures must 
be initiated.
    (5) Autonomous surface vehicle (ASV) use. (i) The ASV must remain 
with 800 m (2,635 ft) of the primary vessel while conducting survey 
operations;
    (ii) Two PSOs must be stationed on the mother vessel at the best 
vantage points to monitor the clearance and shutdown zones around the 
ASV;

[[Page 79168]]

    (iii) At least one PSO must monitor the output of a thermal, high-
definition camera installed on the mother vessel to monitor the field-
of-view around the ASV using a hand-held tablet; and
    (iv) During periods of reduced visibility (e.g., darkness, rain, or 
fog), PSOs must use night-vision goggles with thermal clip-ons and a 
hand-held spotlight to monitor the clearance and shutdown zones around 
the ASV.


Sec.  217.275  Requirements for monitoring and reporting.

    (a) PSO qualifications. Revolution Wind must employ qualified, 
trained visual and acoustic PSOs to conduct marine mammal monitoring 
during activities associated with construction. PSO requirements are as 
follows:
    (1) Revolution Wind must use independent, dedicated, qualified 
PSOs, meaning that the PSOs must be employed by a third-party observer 
provider, must have no tasks other than to conduct observational 
effort, collect data, and communicate with and instruct relevant vessel 
crew with regard to the presence of protected species and mitigation 
requirements in this subpart.
    (2) All PSOs must be approved by NMFS. Revolution Wind must submit 
PSO resumes for NMFS' review and approval at least 60 days prior to 
commencement of in-water construction activities requiring PSOs. 
Resumes must include dates of training and any prior NMFS approval, as 
well as dates and description of last experience, and must be 
accompanied by information documenting successful completion of an 
acceptable training course. NMFS shall be allowed three weeks to 
approve PSOs from the time that the necessary information is received 
by NMFS, after which PSOs meeting the minimum requirements in this 
paragraph (a) will automatically be considered approved.
    (3) PSOs must have visual acuity in both eyes (with correction of 
vision being permissible) sufficient enough to discern moving targets 
on the water's surface with the ability to estimate the target size and 
distance (binocular use is allowable).
    (4) All PSOs must be trained in marine mammal identification and 
behaviors and must be able to conduct field observations and collect 
data according to assigned protocols. Additionally, PSOs must have the 
ability to work with all required and relevant software and equipment 
necessary during observations.
    (5) PSOs must have sufficient writing skills to document all 
observations, including but not limited to:
    (i) The number and species of marine mammals observed;
    (ii) The dates and times of when in-water construction activities 
were conducted;
    (iii) The dates and time when in-water construction activities were 
suspended to avoid potential incidental injury of marine mammals from 
construction noise within a defined shutdown zone; and
    (iv) Marine mammal behavior.
    (6) All PSOs must be able to communicate orally, by radio, or in-
person with Revolution Wind project personnel.
    (7) PSOs must have sufficient training, orientation, or experience 
with construction operations to provide for their own personal safety 
during observations.
    (i) All PSOs must complete a Permits and Environmental Compliance 
Plan training and a two-day refresher session that will be held with 
the PSO provider and Project compliance representative(s) prior to the 
start of construction activities.
    (ii) [Reserved]
    (8) At least one PSO must have prior experience working as an 
observer. Other PSOs may substitute education (i.e., degree in 
biological science or related field) or training for experience.
    (9) One PSO for each activity (i.e., foundation installation, 
cofferdam or casing pipe installation and removal, HRG surveys, UXO/MEC 
detonation) must be designated as the ``Lead PSO''. The Lead PSO must 
have a minimum of 90 days of at-sea experience working in an offshore 
environment and would be required to have no more than eighteen months 
elapsed since the conclusion of their last at-sea experience.
    (10) At a minimum, at least one PSO located on each observation 
platform (either vessel-based or aerial-based) must have a minimum of 
90 days of at-sea experience working in an offshore environment and 
would be required to have no more than eighteen months elapsed since 
the conclusion of their last at-sea experiences. Any new and/or 
inexperienced PSOs would be paired with an experienced PSO.
    (11) PSOs must monitor all clearance and shutdown zones prior to, 
during, and following impact pile driving, vibratory pile driving, 
pneumatic hammering, UXO/MEC detonations, and during HRG surveys that 
use boomers, sparkers, and CHIRPs (with specific monitoring durations 
described in paragraphs (b)(2)(iii), (b)(3)(iv), (b)(4)(ii), and 
(b)(5)(iii) of this section. PSOs must also monitor the Level B 
harassment zones and document any marine mammals observed within these 
zones, to the extent practicable.
    (12) PSOs must be located on the best available vantage point(s) on 
the primary vessel(s) (i.e., pile driving vessel, UXO/MEC vessel, HRG 
survey vessel) and on other dedicated PSO vessels (e.g., additional 
UXO/MEC vessels) or aerial platforms, as applicable and necessary, to 
allow them appropriate coverage of the entire visual shutdown zone(s), 
clearance zone(s), and as much of the Level B harassment zone as 
possible. These vantage points must maintain a safe work environment.
    (13) Acoustic PSOs must complete specialized training for operating 
passive acoustic monitoring (PAM) systems and must demonstrate 
familiarity with the PAM system on which they must be working. PSOs may 
act as both acoustic and visual observers (but not simultaneously), so 
long as they demonstrate that their training and experience are 
sufficient to perform each task.
    (b) PSO requirements--(1) General. (i) All PSOs must be located at 
the best vantage point(s) on the primary vessel, dedicated PSO vessels, 
and aerial platform in order to ensure 360[deg] visual coverage of the 
entire clearance and shutdown zones around the vessels, and as much of 
the Level B harassment zone as possible;
    (ii) During all observation periods, PSOs must use high 
magnification (25x) binoculars, standard handheld (7x) binoculars, and 
the naked eye to search continuously for marine mammals. During impact 
pile driving and UXO/MEC detonation events, at least one PSO on the 
primary pile driving or UXO/MEC vessels must be equipped with Big Eye 
binoculars (e.g., 25 x 150; 2.7 view angle; individual ocular focus; 
height control) of appropriate quality. These must be pedestal mounted 
on the deck at the most appropriate vantage point that provides for 
optimal sea surface observation and PSO safety; and
    (iii) PSOs must not exceed four consecutive watch hours on duty at 
any time, must have a two-hour (minimum) break between watches, and 
must not exceed a combined watch schedule of more than 12 hours in a 
24-hour period.
    (2) WTG and OSS foundation installation. (i) At least four PSOs 
must be actively observing marine mammals before, during, and after 
installation of foundation piles (monopiles). At least two PSOs must be 
stationed and observing on the pile driving vessel and at least two 
PSOs must be stationed on a secondary, PSO-dedicated vessel. 
Concurrently, at least one acoustic PSO (i.e., passive acoustic 
monitoring (PAM) operator) must be actively monitoring for marine 
mammals with PAM before, during and after impact pile driving;

[[Page 79169]]

    (ii) If PSOs cannot visually monitor the minimum visibility zone at 
all times using the equipment described in paragraph (b)(1)(ii) of this 
section, impact pile driving operations must not commence or must 
shutdown if they are currently active;
    (iii) All PSOs, including PAM operators, must begin monitoring 60 
minutes prior to pile driving, during, and for 30 minutes after an 
activity. The impact pile driving of monopiles must only commence when 
the minimum visibility zone is fully visible (e.g., not obscured by 
darkness, rain, fog, etc.) and the clearance zones are clear of marine 
mammals for at least 30 minutes, as determined by the Lead PSO, 
immediately prior to the initiation of impact pile driving;
    (iv) For North Atlantic right whales, any visual or acoustic 
detection must trigger a delay to the commencement of pile driving. In 
the event that a large whale is sighted or acoustically detected that 
cannot be confirmed by species, it must be treated as if it were a 
North Atlantic right whale; and
    (v) Following a shutdown, monopile installation must not recommence 
until the minimum visibility zone is fully visible and clear of marine 
mammals for 30 minutes.
    (3) Cofferdam or casing pipe installation and removal. (i) At least 
two PSOs must be on active duty during all activities related to the 
installation and removal of cofferdams or casing pipes and goal post 
sheet piles;
    (ii) These PSOs must be located at appropriate vantage points on 
the vibratory pile driving or pneumatic hammering platform or secondary 
platform in the immediate vicinity of the vibratory pile driving or 
pneumatic hammering platforms;
    (iii) PSOs must ensure that there is appropriate visual coverage 
for the entire clearance zone and as much of the Level B harassment 
zone as possible; and
    (iv) PSOs must monitor the clearance zone for the presence of 
marine mammals for 30 minutes before, throughout the installation of 
the sheet piles and casing pipes, and for 30 minutes after all 
vibratory pile driving or pneumatic hammering activities have ceased. 
Sheet pile or casing pipe installation shall only commence when visual 
clearance zones are fully visible (e.g., not obscured by darkness, 
rain, fog, etc.) and clear of marine mammals, as determined by the Lead 
PSO, for at least 30 minutes immediately prior to initiation of 
vibratory pile driving or pneumatic hammering.
    (4) UXO/MEC detonations. (i) At least two PSOs must be on active 
duty on each observing platform (i.e., vessel, plane) prior to, during, 
and after UXO/MEC detonations. Concurrently, at least one acoustic PSO 
(i.e., passive acoustic monitoring (PAM) operator) must be actively 
monitoring for marine mammals with PAM before, during and after UXO/MEC 
detonations;
    (ii) All PSOs, including PAM operators, must begin monitoring 60 
minutes prior to UXO/MEC detonation, during detonation, and for 30 
minutes after detonation; and
    (iii) Revolution Wind must ensure that clearance zones are fully 
(100 percent) monitored.
    (5) HRG surveys. (i) Between 4 and 6 PSOs must be present on every 
24-hour survey vessel and 2 to 3 PSOs must be present on every 12-hour 
survey vessel. At least one PSO must be on active duty during HRG 
surveys conducted during daylight and at least two PSOs must be on 
activity duty during HRG surveys conducted at night;
    (ii) During periods of low visibility (e.g., darkness, rain, fog, 
etc.), PSOs must use alternative technology (i.e., infrared/thermal 
camera) to monitor the clearance and shutdown zones;
    (iii) PSOs on HRG vessels must begin monitoring 30 minutes prior to 
activating boomers, sparkers, or CHIRPs, during use of these acoustic 
sources, and for 30 minutes after use of these acoustic sources has 
ceased;
    (iv) Any observations of marine mammals must be communicated to 
PSOs on all nearby survey vessels during concurrent HRG surveys; and
    (v) During daylight hours when survey equipment is not operating, 
Revolution Wind must ensure that visual PSOs conduct, as rotation 
schedules allow, observations for comparison of sighting rates and 
behavior with and without use of the specified acoustic sources. Off-
effort PSO monitoring must be reflected in the monthly PSO monitoring 
reports.
    (c) PAM operator requirements--(1) General. (i) PAM operators must 
have completed specialized training for operating PAM systems prior to 
the start of monitoring activities, including identification of 
species-specific mysticete vocalizations (e.g., North Atlantic right 
whales);
    (ii) During use of any real-time PAM system, at least one PAM 
operator must be designated to monitor each system by viewing data or 
data products that would be streamed in real-time or in near real-time 
to a computer workstation and monitor;
    (iii) PAM operators may be located on a vessel or remotely on-shore 
but must have the appropriate equipment (i.e., computer station 
equipped with a data collection software system (i.e., Mysticetus or 
similar system) and acoustic data analysis software) available wherever 
they are stationed;
    (iv) Visual PSOs must remain in contact with the PAM operator 
currently on duty regarding any animal detection that would be 
approaching or found within the applicable zones no matter where the 
PAM operator is stationed (i.e., onshore or on a vessel);
    (v) The PAM operator must inform the Lead PSO on duty of animal 
detections approaching or within applicable ranges of interest to the 
pile driving activity via the data collection software system (i.e., 
Mysticetus or similar system) who will be responsible for requesting 
that the designated crewmember implement the necessary mitigation 
procedures (i.e., delay or shutdown);
    (vi) PAM operators must be on watch for a maximum of four 
consecutive hours, followed by a break of at least two hours between 
watches; and
    (vii) A Passive Acoustic Monitoring Plan must be submitted to NMFS 
for review and approval at least 180 days prior to the planned start of 
monopile installation. The authorization to take marine mammals would 
be contingent upon NMFS' approval of the PAM Plan.
    (2) WTG and OSS foundation installation. (i) Revolution Wind must 
use a minimum of one PAM operator before, during, and after impact pile 
driving activities. The PAM operator must assist visual PSOs in 
ensuring full coverage of the clearance and shutdown zones;
    (ii) PAM operators must assist the visual PSOs in monitoring by 
conducting PAM activities 60 minutes prior to any impact pile driving, 
during, and after for 30 minutes for the appropriate size PAM clearance 
zone (dependent on season). The entire minimum visibility zone must be 
clear for at least 30 minutes, with no marine mammal detections within 
the visual or PAM clearance zones prior to the start of impact pile 
driving;
    (iii) Any acoustic monitoring during low visibility conditions 
during the day would complement visual monitoring efforts and would 
cover an area of at least the Level B harassment zone around each 
monopile foundation;
    (iv) Any visual or acoustic detection within the clearance zones 
must trigger a delay to the commencement of pile driving. In the event 
that a large whale is sighted or acoustically detected that cannot be 
identified by species, it must be treated as if it were a North 
Atlantic right whale. Following a shutdown, monopile installation shall 
not recommence until the minimum visibility zone is fully visible and 
clear

[[Page 79170]]

of marine mammals for 30 minutes and no marine mammals have been 
detected acoustically within the PAM clearance zone for 30 minutes; and
    (v) Revolution Wind must submit a Pile Driving and Marine Mammal 
Monitoring Plan to NMFS for review and approval at least 180 days 
before the start of any pile driving. The plan must include final 
project design related to pile driving (e.g., number and type of piles, 
hammer type, noise abatement systems, anticipated start date, etc.) and 
all information related to PAM PSO monitoring protocols for pile-
driving and visual PSO protocols for all activities.
    (3) UXO/MEC detonation(s). (i) Revolution Wind must use a minimum 
of one PAM operator before, during, and after UXO/MEC detonations. The 
PAM operator must assist visual PSOs in ensuring full coverage of the 
clearance and shutdown zones;
    (ii) PAM must be conducted for at least 60 minutes prior to 
detonation, during, and for 30 minutes after detonation;
    (iii) The PAM operator must monitor to and beyond the clearance 
zone for large whales; and
    (iv) Revolution Wind must prepare and submit a UXO/MEC and Marine 
Mammal Monitoring Plan to NMFS for review and approval at least 180 
days before the start of any UXO/MEC detonations. The plan must include 
final project design and all information related to visual and PAM PSO 
monitoring protocols for UXO/MEC detonations.
    (d) Data collection and reporting. (1) Prior to initiation of 
project activities, Revolution Wind must demonstrate in a report 
submitted to NMFS (at [email protected] and 
[email protected]) that all required training for 
Revolution Wind personnel (including the vessel crews, vessel captains, 
PSOs, and PAM operators) has been completed.
    (2) Revolution Wind must use a standardized reporting system from 
October 5, 2023 through October 4, 2028, the effective period of this 
subpart and the LOA. All data collected related to the Revolution Wind 
project must be recorded using industry-standard softwares (e.g., 
Mysticetus or a similar software) that is installed on field laptops 
and/or tablets. For all monitoring efforts and marine mammal sightings, 
Revolution Wind must collect the following information and report it to 
NMFS:
    (i) Date and time that monitored activity begins or ends;
    (ii) Construction activities occurring during each observation 
period;
    (iii) Watch status (i.e., sighting made by PSO on/off effort, 
opportunistic, crew, alternate vessel/platform);
    (iv) PSO who sighted the animal;
    (v) Time of sighting;
    (vi) Weather parameters (e.g., wind speed, percent cloud cover, 
visibility);
    (vii) Water conditions (e.g., sea state, tide state, water depth);
    (viii) All marine mammal sightings, regardless of distance from the 
construction activity;
    (ix) Species (or lowest possible taxonomic level possible);
    (x) Pace of the animal(s);
    (xi) Estimated number of animals (minimum/maximum/high/low/best);
    (xii) Estimated number of animals by cohort (e.g., adults, 
yearlings, juveniles, calves, group composition, etc.);
    (xiii) Description (i.e., as many distinguishing features as 
possible of each individual seen, including length, shape, color, 
pattern, scars or markings, shape and size of dorsal fin, shape of 
head, and blow characteristics);
    (xiv) Description of any marine mammal behavioral observations 
(e.g., observed behaviors such as feeding or traveling) and observed 
changes in behavior, including an assessment of behavioral responses 
thought to have resulted from the specific activity;
    (xv) Animal's closest distance and bearing from the pile being 
driven, UXO/MEC, or specified HRG equipment and estimated time entered 
or spent within the Level A harassment and/or Level B harassment zones;
    (xvi) Construction activity at time of sighting (e.g., vibratory 
installation/removal, impact pile driving, UXO/MEC detonation, 
construction survey), use of any noise attenuation device(s), and 
specific phase of activity (e.g., ramp-up of HRG equipment, HRG 
acoustic source on/off, soft start for pile driving, active pile 
driving, post-UXO/MEC detonation, etc.);
    (xvii) Marine mammal occurrence in Level A harassment or Level B 
harassment zones;
    (xviii) Description of any mitigation-related action implemented, 
or mitigation-related actions called for but not implemented, in 
response to the sighting (e.g., delay, shutdown, etc.) and time and 
location of the action; and
    (xix) Other human activity in the area.
    (3) For all real-time acoustic detections of marine mammals, the 
following must be recorded and included in weekly, monthly, annual, and 
final reports:
    (i) Location of hydrophone (latitude & longitude; in Decimal 
Degrees) and site name;
    (ii) Bottom depth and depth of recording unit (in meters);
    (iii) Recorder (model & manufacturer) and platform type (i.e., 
bottom-mounted, electric glider, etc.), and instrument ID of the 
hydrophone and recording platform (if applicable);
    (iv) Time zone for sound files and recorded date/times in data and 
metadata (in relation to UTC., i.e., EST time zone is UTC-5);
    (v) Duration of recordings (start/end dates and times; in ISO 8601 
format, yyyy-mm-ddTHH:MM:SS.sssZ);
    (vi) Deployment/retrieval dates and times (in ISO 8601 format);
    (vii) Recording schedule (must be continuous);
    (viii) Hydrophone and recorder sensitivity (in dB re. 1 mPa);
    (ix) Calibration curve for each recorder;
    (x) Bandwidth/sampling rate (in Hz);
    (xi) Sample bit-rate of recordings; and,
    (xii) Detection range of equipment for relevant frequency bands (in 
meters).
    (4) For each detection, the following information must be noted:
    (i) Species identification (if possible);
    (ii) Call type and number of calls (if known);
    (iii) Temporal aspects of vocalization (date, time, duration, etc.; 
date times in ISO 8601 format);
    (iv) Confidence of detection (detected, or possibly detected);
    (v) Comparison with any concurrent visual sightings;
    (vi) Location and/or directionality of call (if determined) 
relative to acoustic recorder or construction activities;
    (vii) Location of recorder and construction activities at time of 
call;
    (viii) Name and version of detection or sound analysis software 
used, with protocol reference;
    (xi) Minimum and maximum frequencies viewed/monitored/used in 
detection (in Hz); and
    (x) Name of PAM operator(s) on duty.
    (5)(i) Revolution Wind must compile and submit weekly PSO, PAM, and 
sound field verification (SFV) reports to NMFS (at [email protected] 
and [email protected]) that document the daily start 
and stop of all pile driving, HRG survey, or UXO/MEC detonation 
activities, the start and stop of associated observation periods by 
PSOs, details on the deployment of PSOs, a record of all detections of 
marine mammals (acoustic and visual), any mitigation actions (or if 
mitigation actions could not be taken, provide reasons why), and 
details on the noise abatement system(s) used and its performance. 
Weekly reports are due on Wednesday for the previous week (Sunday-
Saturday) and must include the information required under this section. 
The weekly report will also

[[Page 79171]]

identify which turbines become operational and when (a map must be 
provided). Once all foundation pile installation is completed, weekly 
reports are no longer required;
    (ii) [Reserved]
    (6)(i) Revolution Wind must compile and submit monthly reports to 
NMFS (at [email protected] and [email protected]) that 
include a summary of all information in the weekly reports, including 
project activities carried out in the previous month, vessel transits 
(number, type of vessel, and route), number of piles installed, number 
of UXO/MEC detonations, all detections of marine mammals, and any 
mitigative action taken. Monthly reports are due on the 15th of the 
month for the previous month. The monthly report must also identify 
which turbines become operational and when (a map must be provided). 
Once foundation installation is complete, monthly reports are no longer 
required.
    (ii) [Reserved]
    (7)(i) Revolution Wind must submit an annual report to NMFS (at 
[email protected] and [email protected]) no later than 
90 days following the end of a given calendar year. Revolution Wind 
must provide a final report within 30 days following resolution of 
comments on the draft report. The report must detail the following 
information and the information specified in paragraphs (d)(2)(i) 
through (xix), (d)(3)(i) through (xii), and (d)(4)(i) through (x) of 
this section:
    (A) The total number of marine mammals of each species/stock 
detected and how many were within the designated Level A harassment and 
Level B harassment zones with comparison to authorized take of marine 
mammals for the associated activity type;
    (B) Marine mammal detections and behavioral observations before, 
during, and after each activity;
    (C) What mitigation measures were implemented (i.e., number of 
shutdowns or clearance zone delays, etc.) or, if no mitigative actions 
was taken, why not;
    (D) Operational details (i.e., days of impact and vibratory pile 
driving, days/amount of HRG survey effort, total number and charge 
weights related to UXO/MEC detonations, etc.);
    (E) SFV results;
    (F) Any PAM systems used;
    (G) The results, effectiveness, and which noise abatement systems 
were used during relevant activities (i.e., impact pile driving, UXO/
MEC detonation);
    (H) Summarized information related to situational reporting; and
    (I) Any other important information relevant to the Revolution Wind 
project, including additional information that may be identified 
through the adaptive management process.
    (ii) The final annual report must be prepared and submitted within 
30 calendar days following the receipt of any comments from NMFS on the 
draft report. If no comments are received from NMFS within 60 calendar 
days of NMFS' receipt of the draft report, the report must be 
considered final.
    (8)(i) Revolution Wind must submit its draft final report to NMFS 
(at [email protected] and [email protected]) on all 
visual and acoustic monitoring conducted under the LOA within 90 
calendar days of the completion of activities occurring under the LOA. 
A final report must be prepared and submitted within 30 calendar days 
following receipt of any NMFS comments on the draft report. If no 
comments are received from NMFS within 30 calendar days of NMFS' 
receipt of the draft report, the report shall be considered final.
    (ii) [Reserved]
    (9)(i) Revolution Wind must provide the initial results of the SFV 
measurements to NMFS in an interim report after each monopile 
foundation installation for the first three monopiles piles, and for 
each UXO/MEC detonation as soon as they are available, but no later 
than 48 hours after each installation or detonation. Revolution Wind 
must also provide interim reports on any subsequent SFV on foundation 
piles within 48 hours. The interim report must include hammer energies 
used during pile driving or UXO/MEC weight (including donor charge 
weight), peak sound pressure level (SPLpk) and median, mean, 
maximum, and minimum root-mean-square sound pressure level that 
contains 90 percent of the acoustic energy (SPLrms) and 
single strike sound exposure level (SELss); and
    (ii) The final results of SFV of monopile installations must be 
submitted as soon as possible, but no later than within 90 days 
following completion of impact pile driving of monopiles and UXO/MEC 
detonations. The final report must include, at minimum, the following:
    (A) Peak sound pressure level (SPLpk), root-mean-square 
sound pressure level that contains 90 percent of the acoustic energy 
(SPLrms), single strike sound exposure level 
(SELss), integration time for SPLrms, spectrum, 
and 24-hour cumulative SEL extrapolated from measurements at specified 
distances (e.g., 750 m). All these levels must be reported in the form 
of median, mean, maximum, and minimum. The SEL and SPL power spectral 
density and one-third octave band levels (usually calculated as 
decidecade band levels) at the receiver locations should be reported;
    (B) The sound levels reported must be in median and linear average 
(i.e., average in linear space), and in dB;
    (C) A description of depth and sediment type, as documented in the 
Construction and Operation Plan, at the recording and pile driving 
locations;
    (D) Hammer energies required for pile installation and the number 
of strikes per pile;
    (E) Hydrophone equipment and methods (i.e., recording device, 
bandwidth/sampling rate, distance from the pile where recordings were 
made; depth of recording device(s));
    (F) Description of the SFV PAM hardware and software, including 
software version used, calibration data, bandwidth capability and 
sensitivity of hydrophone(s), any filters used in hardware or software, 
any limitations with the equipment, and other relevant information;
    (G) Description of UXO/MEC, weight, including donor charge weight, 
and why detonation was necessary;
    (H) Local environmental conditions, such as wind speed, 
transmission loss data collected on-site (or the sound velocity 
profile), baseline pre- and post-activity ambient sound levels 
(broadband and/or within frequencies of concern);
    (I) Spatial configuration of the noise attenuation device(s) 
relative to the pile;
    (J) The extents of the Level A harassment and Level B harassment 
zones; and
    (K) A description of the noise abatement system and operational 
parameters (e.g., bubble flow rate, distance deployed from the pile, 
etc.) and any action taken to adjust the noise abatement system.
    (10) Specific situations encountered during the development of 
Revolution Wind shall require immediate reporting to be undertaken. 
These situations and the relevant procedures are described in 
paragraphs (d)(10)(i) through (v) of this section.
    (i) If a North Atlantic right whale is observed at any time by PSOs 
or personnel on or in the vicinity of any project vessel, or during 
vessel transit, Revolution Wind must immediately report sighting 
information to the NMFS North Atlantic Right Whale Sighting Advisory 
System (866) 755-6622, through the WhaleAlert app (https://

[[Page 79172]]

www.whalealert.org/), and to the U.S. Coast Guard via channel 16, as 
soon as feasible but no longer than 24 hours after the sighting. 
Information reported must include, at a minimum: time of sighting, 
location, and number of North Atlantic right whales observed.
    (ii) When an observation of a marine mammal occurs during vessel 
transit, the following information must be recorded:
    (A) Time, date, and location;
    (B) The vessel's activity, heading, and speed;
    (C) Sea state, water depth, and visibility;
    (D) Marine mammal identification to the best of the observer's 
ability (e.g., North Atlantic right whale, whale, dolphin, seal);
    (E) Initial distance and bearing to marine mammal from vessel and 
closest point of approach; and
    (F) Any avoidance measures taken in response to the marine mammal 
sighting.
    (iii) If a North Atlantic right whale is detected via PAM, the 
date, time, location (i.e., latitude and longitude of recorder) of the 
detection as well as the recording platform that had the detection must 
be reported to [email protected] as soon as feasible, but no 
longer than 24 hours after the detection. Full detection data and 
metadata must be submitted monthly on the 15th of every month for the 
previous month via the webform on the NMFS North Atlantic right whale 
Passive Acoustic Reporting System website (https://www.fisheries.noaa.gov/resource/document/passive-acoustic-reporting-system-templates).
    (iv) In the event that the personnel involved in the activities 
defined in Sec.  217.270(a) discover a stranded, entangled, injured, or 
dead marine mammal, Revolution Wind must immediately report the 
observation to the NMFS Office of Protected Resources (OPR), the NMFS 
Greater Atlantic Stranding Coordinator for the New England/Mid-Atlantic 
area (866-755-6622), and the U.S. Coast Guard within 24 hours. If the 
injury or death was caused by a project activity, Revolution Wind must 
immediately cease all activities until NMFS OPR is able to review the 
circumstances of the incident and determine what, if any, additional 
measures are appropriate to ensure compliance with the terms of the 
LOA. NMFS may impose additional measures to minimize the likelihood of 
further prohibited take and ensure MMPA compliance. Revolution Wind may 
not resume their activities until notified by NMFS. The report must 
include the following information:
    (A) Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
    (B) Species identification (if known) or description of the 
animal(s) involved;
    (C) Condition of the animal(s) (including carcass condition if the 
animal is dead);
    (D) Observed behaviors of the animal(s), if alive;
    (E) If available, photographs or video footage of the animal(s); 
and
    (F) General circumstances under which the animal was discovered.
    (v) In the event of a vessel strike of a marine mammal by any 
vessel associated with the Revolution Wind Offshore Wind Farm Project, 
Revolution Wind must immediately report the strike incident to the NMFS 
OPR and the GARFO within and no later than 24 hours. Revolution Wind 
must immediately cease all activities until NMFS OPR is able to review 
the circumstances of the incident and determine what, if any, 
additional measures are appropriate to ensure compliance with the terms 
of the LOA. NMFS may impose additional measures to minimize the 
likelihood of further prohibited take and ensure MMPA compliance. 
Revolution Wind may not resume their activities until notified by NMFS. 
The report must include the following information:
    (A) Time, date, and location (latitude/longitude) of the incident;
    (B) Species identification (if known) or description of the 
animal(s) involved;
    (C) Vessel's speed leading up to and during the incident;
    (D) Vessel's course/heading and what operations were being 
conducted (if applicable);
    (E) Status of all sound sources in use;
    (F) Description of avoidance measures/requirements that were in 
place at the time of the strike and what additional measures were 
taken, if any, to avoid strike;
    (G) Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, visibility) immediately preceding the 
strike;
    (H) Estimated size and length of animal that was struck;
    (I) Description of the behavior of the marine mammal immediately 
preceding and following the strike;
    (J) If available, description of the presence and behavior of any 
other marine mammals immediately preceding the strike;
    (K) Estimated fate of the animal (e.g., dead, injured but alive, 
injured and moving, blood or tissue observed in the water, status 
unknown, disappeared); and
    (L) To the extent practicable, photographs or video footage of the 
animal(s).


Sec.  217.276  Letter of Authorization.

    (a) To incidentally take marine mammals pursuant to this subpart, 
Revolution Wind must apply for and obtain an LOA.
    (b) An LOA, unless suspended or revoked, may be effective for a 
period of time not to exceed October 4, 2028, the expiration date of 
this subpart.
    (c) If an LOA expires prior to October 4, 2028, the expiration date 
of this subpart, Revolution Wind may apply for and obtain a renewal of 
the LOA.
    (d) In the event of projected changes to the activity or to 
mitigation and monitoring measures required by an LOA, Revolution Wind 
must apply for and obtain a modification of the LOA as described in 
Sec.  217.277.
    (e) The LOA must set forth:
    (1) Permissible methods of incidental taking;
    (2) Means of effecting the least practicable adverse impact (i.e., 
mitigation) on the species, its habitat, and on the availability of the 
species for subsistence uses; and
    (3) Requirements for monitoring and reporting.
    (f) Issuance of the LOA must be based on a determination that the 
level of taking must be consistent with the findings made for the total 
taking allowable under this subpart.
    (g) Notice of issuance or denial of an LOA must be published in the 
Federal Register within 30 days of a determination.


Sec.  217.277  Modifications of Letter of Authorization.

    (a) An LOA issued under Sec. Sec.  217.272 and 217.276 or Sec.  
217.277 for the activity identified in Sec.  217.270(a) shall be 
modified upon request by the applicant, provided that:
    (1) The proposed specified activity and mitigation, monitoring, and 
reporting measures, as well as the anticipated impacts, are the same as 
those described and analyzed for this subpart (excluding changes made 
pursuant to the adaptive management provision in paragraph (c)(1) of 
this section); and
    (2) NMFS determines that the mitigation, monitoring, and reporting 
measures required by the previous LOA under this subpart were 
implemented.
    (b) For a LOA modification request by the applicant that include 
changes to the activity or the mitigation, monitoring, or reporting 
(excluding

[[Page 79173]]

changes made pursuant to the adaptive management provision in paragraph 
(c)(1) of this section) that do not change the findings made for this 
subpart or result in no more than a minor change in the total estimated 
number of takes (or distribution by species or years), NMFS may publish 
a notice of proposed LOA in the Federal Register, including the 
associated analysis of the change, and solicit public comment before 
issuing the LOA.
    (c) An LOA issued under Sec. Sec.  217.272 and 217.276 or Sec.  
217.277 for the activities identified in Sec.  217.270(a) may be 
modified by NMFS under the following circumstances:
    (1) Adaptive management. NMFS may modify (including augment) the 
existing mitigation, monitoring, or reporting measures (after 
consulting with Revolution Wind regarding the practicability of the 
modifications) if doing so creates a reasonable likelihood of more 
effectively accomplishing the goals of the mitigation and monitoring 
set forth in this subpart.
    (i) Possible sources of data that could contribute to the decision 
to modify the mitigation, monitoring, or reporting measures in an LOA:
    (A) Results from Revolution Wind's monitoring from the previous 
year(s);
    (B) Results from other marine mammals and/or sound research or 
studies;
    (C) Any information that reveals marine mammals may have been taken 
in a manner, extent or number not authorized by this subpart or 
subsequent LOA; and
    (ii) If, through adaptive management, the modifications to the 
mitigation, monitoring, or reporting measures are substantial, NMFS 
shall publish a notice of proposed LOA in the Federal Register and 
solicit public comment.
    (2) Emergencies. If NMFS determines that an emergency exists that 
poses a significant risk to the well-being of the species or stocks of 
marine mammals specified in the LOA issued pursuant to Sec. Sec.  
217.272 and 217.276 or Sec.  217.277, an LOA may be modified without 
prior notice or opportunity for public comment. Notice would be 
published in the Federal Register within thirty days of the action.

Sec. Sec.  217.278-217.279  [Reserved]

[FR Doc. 2022-27491 Filed 12-16-22; 4:15 pm]
BILLING CODE 3510-22-P