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Proposed Rule2022-27491

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

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Published

December 23, 2022

Issuing agencies

Commerce DepartmentNational Oceanic and Atmospheric Administration

Abstract

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.

Full Text

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<title>Federal Register, Volume 87 Issue 246 (Friday, December 23, 2022)</title>
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[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 [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2022-27491]

[[Page 79071]]

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

[[Page 79072]]

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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 <a href="http://www.regulations.gov">www.regulations.gov</a> 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
<a href="http://www.regulations.gov">www.regulations.gov</a> 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: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable</a>. 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:
<bullet> 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);
<bullet> 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]]

<bullet> Requiring that any UXO/MEC detonations may only occur
during hours of daylight and not during hours of darkness or nighttime.
<bullet> 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;
<bullet> Requiring the use of sound attenuation device(s) during
all impact pile driving and UXO/MEC detonations to reduce noise levels;
<bullet> 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;
<bullet> Delaying the start of pile driving if other marine mammals
are observed entering or within their respective clearance zones;
<bullet> Shutting down pile driving (if feasible) if a North
Atlantic right whale is observed or if other marine mammals enter their
respective shutdown zones;
<bullet> Implementing soft starts for impact pile driving and using
the lowest hammer energy possible;
<bullet> Implementing ramp-up for high-resolution geophysical (HRG)
site characterization survey equipment;
<bullet> Requiring PSOs to continue to monitor for 30 minutes after
any impact pile driving occurs and for any and all UXO/MEC detonations;
<bullet> 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;
<bullet> Implementing numerous vessel strike avoidance measures;
<bullet> A requirement to implement noise abatement system(s)
during all impact pile driving and UXO/MEC detonations;
<bullet> 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
<bullet> 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: <a href="https://www.permits.performance.gov/permitting-projects/revolution-wind-farm-project">https://www.permits.performance.gov/permitting-projects/revolution-wind-farm-project</a>.

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: <a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-revolution-wind-llc-construction-revolution-wind-energy">https://www.fisheries.noaa.gov/action/incidental-take-authorization-revolution-wind-llc-construction-revolution-wind-energy</a>.
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: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable</a>.
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\
----------------------------------------------------------------------------------------------------------------
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 (SEL<INF>cum</INF>) 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:
<bullet> 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.
<bullet> 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.
<bullet> 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:
<bullet> 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).
<bullet> Foundation Marshaling and Advanced Foundation Component
Fabrication: Port of Providence (Rhode Island), Paulsboro Marine
Terminal (New Jersey), and/or Sparrows Point (Maryland).
<bullet> 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).
<bullet> 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: <a href="https://www.boem.gov/renewable-energy/state-activities/revolution-wind-farm-construction-and-operations-plan">https://www.boem.gov/renewable-energy/state-activities/revolution-wind-farm-construction-and-operations-plan</a>.
Cable laying, cable installation, and cable burial activities
planned to occur during the construction of Revolution Wind may include
the following:
<bullet> Jetting;
<bullet> Vertical injection;
<bullet> Leveling;
<bullet> Mechanical cutting;
<bullet> Plowing (with or without jet-assistance);
<bullet> Pre-trenching; and,
<bullet> 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
<a href="https://www.boem.gov/renewable-energy/state-activities/revolution-wind-farm-construction-and-operations-plan">https://www.boem.gov/renewable-energy/state-activities/revolution-wind-farm-construction-and-operations-plan</a>.
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; <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and more general information about these species
(e.g., physical and behavioral descriptions) may be found on NMFS's
website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
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: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports</a>.

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: <a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>
(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 (<a href="https://www.fisheries.noaa.gov/species/north-atlantic-right-whale">https://www.fisheries.noaa.gov/species/north-atlantic-right-whale</a>).
\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
(<a href="https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/">https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/</a>; 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: <a href="https://www.fws.gov/species/manatee-trichechus-manatus">https://www.fws.gov/species/manatee-trichechus-manatus</a>.
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
(<a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-revolution-wind-llc-construction-revolution-wind-energy">https://www.fisheries.noaa.gov/action/incidental-take-authorization-revolution-wind-llc-construction-revolution-wind-energy</a>), the SARs
(<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>), and NMFS' website (<a href="https://www.fisheries.noaa.gov/species-directory/marine-mammals">https://www.fisheries.noaa.gov/species-directory/marine-mammals</a>), 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 <a href="https://www.fisheries.noaa.gov/national/marine-life-distress/active-and-closed-unusual-mortality-events">https://www.fisheries.noaa.gov/national/marine-life-distress/active-and-closed-unusual-mortality-events</a>.
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 (<a href="https://www.fisheries.noaa.gov/action/initiation-5-year-review-north-atlantic-right-whale">https://www.fisheries.noaa.gov/action/initiation-5-year-review-north-atlantic-right-whale</a>).
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) (<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>). 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 (<a href="https://www.fisheries.noaa.gov/species/north-atlantic-right-whale">https://www.fisheries.noaa.gov/species/north-atlantic-right-whale</a>). 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: <a href="http://www.fisheries.noaa.gov/national/marine-life-distress/2017-2021-north-atlantic-right-whale-unusual-mortality-event">www.fisheries.noaa.gov/national/marine-life-distress/2017-2021-north-atlantic-right-whale-unusual-mortality-event</a>.
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 (<a href="https://apps-nefsc.fisheries.noaa.gov/psb/surveys/MapperiframeWithText.html">https://apps-nefsc.fisheries.noaa.gov/psb/surveys/MapperiframeWithText.html</a>). 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: <a href="http://www.fisheries.noaa.gov/national/marine-life-distress/2016-2021-humpback-whale-unusual-mortality-event-along-atlantic-coast">www.fisheries.noaa.gov/national/marine-life-distress/2016-2021-humpback-whale-unusual-mortality-event-along-atlantic-coast</a>.
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: <a href="http://www.fisheries.noaa.gov/national/marine-life-distress/2017-2021-minke-whale-unusual-mortality-event-along-atlantic-coast">www.fisheries.noaa.gov/national/marine-life-distress/2017-2021-minke-whale-unusual-mortality-event-along-atlantic-coast</a>.
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: <a href="http://www.fisheries.noaa.gov/new-england-mid-atlantic/marine-life-distress/2018-2020-pinniped-unusual-mortality-event-along">www.fisheries.noaa.gov/new-england-mid-atlantic/marine-life-distress/2018-2020-pinniped-unusual-mortality-event-along</a>.
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;
SEL<INF>ss</INF>), or calculated over periods containing multiple
pulses (SEL<INF>cum</INF>). 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

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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-

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