Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the New England Wind Project Offshore Massachusetts, 37606-37702 [2023-11814]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 88, Number 110 (Thursday, June 8, 2023)]
[Proposed Rules]
[Pages 37606-37702]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-11814]



[[Page 37605]]

Vol. 88

Thursday,

No. 110

June 8, 2023

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 New England Wind Project Offshore 
Massachusetts; Proposed Rule

Federal Register / Vol. 88 , No. 110 / Thursday, June 8, 2023 / 
Proposed Rules

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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 217

[Docket No. 230530-0140]
RIN 0648-BL96


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to the New England Wind Project 
Offshore Massachusetts

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

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

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SUMMARY: NMFS has received a request from Park City Wind, LLC (Park 
City Wind) for Incidental Take Regulations (ITR) and an associated 
Letter of Authorization (LOA) pursuant to the Marine Mammal Protection 
Act (MMPA). 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 (2025-2030) incidental to 
construction of the New England Wind Project. Park City Wind proposes 
to develop the New England Wind Project in two phases, known as Park 
City Wind (Phase 1) and Commonwealth Wind (Phase 2). Project activities 
that may result in incidental take include pile driving (impact and 
vibratory), drilling, unexploded ordnance or munitions and explosives 
of concern (UXO/MEC) detonation, and vessel-based site assessment 
surveys using high-resolution geophysical (HRG) equipment. NMFS 
requests comments on this 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 rule, if issued. If adopted, 
the proposed regulations would be effective March 27, 2025, through 
March 26, 2030.

DATES: Comments and information must be received no later than July 10, 
2023.

ADDRESSES: Submit all electronic public comments via the Federal e-
Rulemaking Portal. Go to www.regulations.gov and enter NOAA-NMFS-2023-
0080 in the Search box. Click on the ``Comment'' icon, complete the 
required fields, and enter or attach your comments.
    Instructions: Comments sent by any other method, to any other 
address or individual, or received after the end of the comment period, 
may not be considered by NMFS. All comments received are a part of the 
public record and will generally be posted for public viewing on 
www.regulations.gov without change. All personal identifying 
information (e.g., name, address), confidential business information, 
or otherwise sensitive information submitted voluntarily by the sender 
will be publicly accessible. NMFS will accept anonymous comments (enter 
``N/A'' in the required fields if you wish to remain anonymous). 
Attachments to electronic comments will be accepted in Microsoft Word, 
Excel, or Adobe PDF file formats only.

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

SUPPLEMENTARY INFORMATION: 

Availability

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

Purpose and Need for Regulatory Action

    This proposed rule would provide a framework under the authority of 
the MMPA (16 U.S.C. 1361 et seq.) to allow for the authorization of 
take of marine mammals incidental to construction of the New England 
Wind Project within the Bureau of Ocean Energy Management (BOEM) 
Renewable Energy Lease Area OCS-A 0534, the southwest (SW) portion of 
Lease Area OCS-A 0501, and along an export cable corridor to a landfall 
location in Massachusetts. NMFS received a request from Park City Wind 
for 5-year regulations and an LOA that would authorize take, by Level A 
harassment and/or Level B harassment, of 39 species of marine mammals 
incidental to Park City Wind's construction activities. After reviewing 
the request, NMFS is proposing to authorize the take, by harassment 
only, of 38 species, representing 38 stocks. No mortality or serious 
injury is anticipated or proposed for authorization. Please see the 
Estimated Take of Marine Mammals section below for definitions of 
relevant terms.

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.
    As noted above, no serious injury or mortality is anticipated or 
proposed for authorization in this proposed rule. Relevant definitions 
of MMPA statutory and regulatory terms are included below:
     Citizen--individual U.S. citizens or any corporation or 
similar entity if it is organized under the laws of the United States 
or any governmental unit defined in 16 U.S.C. 1362(13) (see 50 CFR 
216.103);
     Take--to harass, hunt, capture, or kill, or attempt to 
harass, hunt, capture, or kill any marine mammal (16 U.S.C. 1362);
     Incidental taking--an accidental taking. This does not 
mean that the taking is unexpected, but rather it includes those 
takings that are infrequent, unavoidable or accidental (see 50 CFR 
216.103);
     Serious Injury--any injury that will likely result in 
mortality (50 CFR 216.3);
     Level A harassment--any act of pursuit, torment, or 
annoyance which has the potential to injure a marine mammal or marine 
mammal stock in the wild (16 U.S.C. 1362; 50 CFR 216.3); and
     Level B harassment--any act of pursuit, torment, or 
annoyance which

[[Page 37607]]

has the potential to disturb a marine mammal or marine mammal stock in 
the wild by causing disruption of behavioral patterns, including, but 
not limited to, migration, breathing, nursing, breeding, feeding, or 
sheltering (16 U.S.C. 1362).
    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 5-year regulations and an associated LOA. 
This proposed rule also establishes required mitigation, monitoring, 
and reporting requirements for Park City Wind's activities.

Summary of Major Provisions Within the Proposed Action

    The major provisions within this proposed rule are as follows:
     Authorize take of marine mammals by Level A harassment 
and/or Level B harassment.
     No mortality or serious injury of any marine mammal is 
proposed to be authorized;
     Establish a seasonal moratorium on foundation installation 
and UXO/MEC detonations during the months of highest North Atlantic 
right whale (Eubalaena glacialis) presence in the project area (no 
foundation installation or UXO/MEC detonation from January 1-April 30; 
no vibratory pile driving in May and December; impact pile driving and 
drilling activities would not be planned or occur in December unless 
due to unforeseen circumstances and only with NMFS' approval; UXO/MEC 
detonations would not be planned or occur in December or May unless due 
to unforeseen circumstances and only with NMFS' approval);
     Enhanced North Atlantic right whale clearance, shutdown 
and restart procedures May 1 through May 14 and November 1 through 
December 31 (if a seasonally-restricted activity is approved in 
December due to unforeseen circumstances);
     Require both visual and passive acoustic monitoring by 
trained, NOAA Fisheries-approved Protected Species Observers (PSOs) and 
Passive Acoustic Monitoring (PAM; where required) operators before, 
during, and after select activities;
     Require the use of sound attenuation device(s) during all 
foundation installation activities and UXO/MEC detonations to reduce 
noise levels;
     Delay the start of foundation installation and UXO/MEC 
detonations if a North Atlantic right whale is observed at any distance 
by PSOs or acoustically detected within certain distances;
     Delay the start of foundation installation and UXO/MEC 
detonations if other marine mammals are observed entering or within 
their respective clearance zones;
     Shut down pile driving (if feasible) if a North Atlantic 
right whale is observed or if other marine mammals enter their 
respective shut down zones;
     Implement sound field verification requirements during 
impact pile driving and UXO/MEC detonations to measure in situ noise 
levels for comparison against the model results;
     Implement soft-starts for impact pile driving and use the 
least hammer energy possible;
     Require PSOs to continue to monitor for the presence of 
marine mammals for 30 minutes after any impact pile driving occurs;
     Implement ramp-up for HRG site characterization survey 
equipment;
     Increase awareness of North Atlantic right whale presence 
through monitoring of the appropriate networks and Channel 16, as well 
as reporting any sightings to the sighting network;
     Implement various vessel strike avoidance measures;
     Implement Best Management Practices (BMPs) during 
fisheries monitoring surveys, such as removing gear from the water if 
marine mammals are considered at-risk or are interacting with gear; and
     Require frequent scheduled and situational reporting 
including, but not limited to, information regarding activities 
occurring, marine mammal observations and acoustic detections, and 
sound field verification monitoring results.
    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 the 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, ``New England Wind Draft Environmental Impact Statement (DEIS) for 
Commercial Wind Lease OCS-A0534'', was made available for public 
comment on December 23, 2022 (87 FR 78993), beginning the 60-day 
comment period ending on February 21, 2023. Additionally, BOEM held 
three virtual public hearings on January 27, February 1, and February 
6, 2023.
    Information contained within Park City Wind's incidental take 
authorization (ITA) application and this Federal Register document 
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 notice of 
proposed rulemaking prior to concluding the NEPA process or making a 
final decision on the requested 5-year ITR 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).
    Park City 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 at https://www.permits.performance.gov/permitting-project/new-england-wind.

Summary of Request

    On December 1, 2021, Park City Wind, a limited liability company 
registered in the State of Delaware and wholly owned subsidiary of 
Avangrid Renewables, LLC, submitted a request for the promulgation of 
regulations and issuance of an associated 5-year LOA to

[[Page 37608]]

take marine mammals incidental to construction activities associated 
with implementation of the New England Wind Project (hereafter 
``Project'') offshore of Massachusetts in the BOEM Lease Area OCS-A 
0534 and the possible use of their southwest (SW) portion of Lease Area 
OCS-A 0501. The request was for the incidental, but not intentional, 
taking of a small number of 39 marine mammal species (comprising 38 
stocks). Neither Park City Wind nor NMFS expects serious injury or 
mortality to result from the specified activities nor is any proposed 
for authorization.
    Park City Wind is proposing to develop the Project in two phases 
with a maximum of 132 wind turbine generators (WTGs) and electrical 
service platforms (ESP) positions. Two positions may potentially have 
co-located ESPs (i.e., two foundations installed at one grid position); 
hence, the 132 foundations would be installed at 130 positions in the 
lease area. Phase 1 would include 41 to 62 WTGs and 1 or 2 ESPs while 
Phase 2 would include 64 to 88 WTG/ESP positions (up to 3 of those 
positions will be occupied by ESPs). Four or five offshore export 
cables will transmit electricity generated by the WTGs to onshore 
transmission systems in the Town of Barnstable, Massachusetts.
    In response to our questions and comments and following extensive 
information exchange between Park City Wind and NMFS, Park City Wind 
submitted a final revised application on July 13, 2022. NMFS deemed it 
adequate and complete on July 20, 2022. This final application is 
available on NMFS' website at https://www.fisheries.noaa.gov/protected-resource-regulations.
    On August 22, 2022, NMFS published a notice of receipt (NOR) of 
Park City Wind's adequate and complete application in the Federal 
Register (87 FR 51345), requesting public comments and information on 
Park City Wind's request during a 30-day public comment period. During 
the NOR public comment period, NMFS received comment letters from one 
private citizen and one non-governmental organization (ALLCO Renewable 
Energy Limited). NMFS has reviewed all submitted material and has taken 
the material into consideration during the drafting of this proposed 
rule. In January 2023 and again in March 2023, Park City Wind submitted 
memos to NMFS detailing updates and changes to their ITA application 
(``Application Update Report''). These are available on the NMFS 
website at https://www.fisheries.noaa.gov/action/incidental-take-authorization-park-city-wind-llc-construction-new-england-wind-offshore-wind.
    NMFS previously issued one Incidental Harassment Authorization 
(IHA) to Park City Wind for the taking of marine mammals incidental to 
marine site characterization surveys, using high-resolution geophysical 
(HRG) of the Project Phase 1 in the BOEM Lease Area OCS-A 0534 (87 FR 
44087, July 07, 2022). NMFS has also previously issued another IHA to 
Avangrid Renewables, LLC (Avangrid), owner of Park City Wind, LLC, to 
take small numbers of marine mammals incidental to an HRG survey for a 
BOEM Lease Area (OCS-A 0508) off the coasts of North Carolina and 
Virginia (84 FR 31032, June 28, 2019). To date, Park City Wind and 
Avangrid have complied with all IHA requirements (e.g., mitigation, 
monitoring, and reporting). Applicable monitoring results may be found 
in the Estimated Take of Marine Mammals section. If available, the full 
monitoring reports can be found on NMFS' website at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable.
    On August 1, 2022, NMFS announced proposed changes to the existing 
North Atlantic right whale vessel speed regulations (87 FR 46921, 
August 1, 2022) 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. Should a final vessel speed rule 
be issued and become effective during the effective period of this ITR 
(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 on the effective date, NMFS would also notify 
Park City 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 Activities

Overview

    Park City Wind has proposed to construct and operate a wind energy 
facility in State and Federal waters in the Atlantic Ocean in lease 
area OCS-A 0534. This lease area is located within the Massachusetts 
Wind Energy Area (MA WEA) and adjacent to the Rhode Island/
Massachusetts Wind Energy Area (RI/MA WEA). The Project will occupy all 
of Lease Area OCS-A 0534 and potentially a portion of Lease Area OCS-A 
0501 in the event that Vineyard Wind 1 does not develop spare or extra 
positions included in Lease Area OCS-A 0501. If Vineyard Wind 1 does 
not develop spare or extra positions in Lease Area OCS-A 0501, those 
positions would be assigned to Lease Area OCS-A 0534. Accordingly, for 
the purposes of the LOA, Park City Wind has defined the Southern Wind 
Development Area (SWDA) as all of Lease Area OCS-A 0534 and the 
southwest portion of Lease Area OCS-A 0501.
    The Project would consist of several different types of permanent 
offshore infrastructure, including wind turbine generators (WTGs) and 
associated foundations, ESPs, and offshore cabling. Onshore cabling, 
substations, and operations and maintenance (O&M) facilities are also 
planned. The Project is divided into two phases: Park City Wind (Phase 
1) and Commonwealth Wind (Phase 2). Phase 1 would occupy 150-231 km\2\ 
(37,066-57,081 acres) which would include 41-62 WTGs and 1-2 ESPs. 
Phase 1 includes two WTG foundation types: monopiles and piled jackets. 
The ESP(s) will also be supported by a monopile or jacket foundation. 
Strings of WTGs will connect with the ESP(s) via a submarine inter-
array cable transmission system. Two high-voltage alternating current 
(HVAC) offshore export cables, up to 101 km (62.8 mi) in length per 
cable, would be installed within the SWDA. An Offshore Export Cable 
Corridor (OECC) would transmit electricity from the ESP(s) to a 
landfall site.
    Phase 2 depends upon the final footprint of Phase 1. Phase 2 is 
expected to contain 64 to 88 WTGs and 1-3 ESP positions within an area 
ranging from 222-303 km\2\ (54,857-74,873 acres). Phase 2 includes 
three general WTG foundation types: monopiles, jackets (with piles or 
suction buckets), or bottom-frame foundations (with piles or suction 
buckets). Inter-array cables will transmit electricity from the WTGs to

[[Page 37609]]

the ESP(s). The ESP(s) will also be supported by a monopile or jacket 
foundation (with piles or suction buckets). Two or three HVAC offshore 
export cables, each with a maximum length of 116-124 km (63-67 NM) per 
cable, will transmit power from the ESP(s) to shore. All Phase 2 
offshore export cables are planned to use the same OECC as the Phase 1. 
Cables for Phase 1 and Phase 2 will diverge 2-3 km (1-2 mi) from shore 
to unique landfall locations.
    The installation of WTGs and ESPs, would require impact and 
vibratory pile driving and drilling. Work would also include HRG 
vessel-based site characterization surveys using active acoustic 
sources with frequencies of less than 180 kHz and the potential 
detonations of 10 unexploded ordnances or Munitions and Explosives of 
Concern (UXO/MEC) of different charge weights. Additionally, project 
plans include trenching, laying, and burial activities associated with 
the installation of the export cable route from the ESP to the shore-
based landing locations and the inter-array cables between turbines; 
site preparation work (e.g., boulder removal); placement of scour 
protection around foundations; and several types of fishery and 
ecological monitoring surveys. 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 will 
connect to onshore export cables, substations, and grid connections, 
which would be located in Barnstable County, Massachusetts. Marine 
mammals exposed to elevated noise levels during impact and vibratory 
pile driving, drilling, detonations of UXOs, or site characterization 
surveys may be taken by Level A harassment and/or Level B harassment 
depending on the specified activity. No serious injury or mortality is 
anticipated or proposed for authorization.

Dates and Duration

    Park City Wind anticipates that the Project activities with the 
potential to result in harassment of marine mammals would occur 
throughout all 5 years of the proposed regulations which, if 
promulgated, would be effective from March 27, 2025 through March 26, 
2030. The estimated schedule, including dates and duration, for various 
activities is provided in Table 1 (also see Tables 1-3 in Application 
Update Report). However, this proposed rule considers the potential for 
activity schedules to shift. Detailed information about the activities 
themselves may be found in the Detailed Description of the Specific 
Activities subsection.

    Table 1--Estimated Activity Schedule To Construct and Operate the
                                 Project
------------------------------------------------------------------------
        Project activity          Estimated schedule  Estimated duration
------------------------------------------------------------------------
HRG Surveys.....................  Q1 2025-Q4 2029...  Any time of the
                                                       year, up to 25
                                                       days per year.
Scour Protection Pre- or Post-    Q1 2025-Q4 2029...  Any time of the
 Installation.                                         year.
WTG and ESP Foundation            Q2-Q4 2026 and      Up to 8 months per
 Installation, Schedule A.         2027 \1\.           year.
WTG and ESP Foundation            Q2-Q4 2026, 2027,   Up to 8 months per
 Installation, Schedule B.         and 2028 \1\.       year.
Horizontal Directional Drilling   Q4 2025-Q2 2026...  Up to 150 days.
 at Cable Landfall Sites.
UXO/MEC Detonations.............  Q2-Q4 2025 and      Up to 6 days in
                                   2026 \3\.           2025 and 4 days
                                                       in 2026. No more
                                                       than 10 days
                                                       total.
Inter-array Cable Installation..  Q3-Q4 2026 and Q2   Phase 1: 5 months;
                                   2027-Q2 2028.       \2\ Phase 2: 10
                                                       months.\2\
Export Cable Installation and     Q2 2026-Q2 2028...  Phase 1: 8-9
 Termination.                                          months; \1\ Phase
                                                       2: 13-17
                                                       months.\1\
Fishery Monitoring Surveys......  Q1 2025-Q4 2029...  Any time of year.
                                 ---------------------------------------
Turbine Operation...............  Initial turbines operational 2027, all
                                       turbines operational by 2028.
------------------------------------------------------------------------
\1\ Foundation installation pile driving would be limited to May 1-
  December 31, annually; however, pile driving in December will not be
  planned but may occur due to unforeseen circumstances (e.g.,
  unanticipated extended weather delays, unexpected technical
  difficulties) and with NMFS approval.
\2\ The Project is divided into 2 phases: Park City Wind (Phase 1) and
  Commonwealth Wind (Phase 2).
\3\ Park City Wind requested UXO/MEC detonations be allowed Q1 2025-Q4
  2026. We propose to only allow it May-December 2025 and 2026.

Specific Geographic Region

    Park City Wind would construct the Project in Federal waters 
offshore of Massachusetts (Figure 1). The project area is part of the 
Rhode Island/Massachusetts Wind Energy Area (RI-MA WEA). The project 
area covers approximately 101,590 acres (411 km\2\) in Lease Area OCS-A 
0534. The project area is located about 20 miles (32 km) southwest of 
Martha's Vineyard, about 24 miles (39 km) south of Nantucket, and 
adjacent to the southwest boundary of the BOEM-approved Vineyard Wind 1 
energy project (Lease Area OCS-A 0501; 65,296 acres (262 km\2\) 
assigned for potential Project development). Water depths in the 
project area range from 43 to 62 m (141-203 ft) and in the OECC range 
from less than 2 m to 46 m (<7-151 ft). The onshore components of the 
Project will include up to three export cable landfalls in Barnstable 
County, Massachusetts (one for Phase 1 and up to two for Phase 2).
    Park City 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 NES LME, which 
extends between Cape Hatteras, North Carolina, and Martha's Vineyard, 
Massachusetts, extending westward into the Atlantic to the 100-m 
isobath. In the Mid-Atlantic Bight, which extends from Massachusetts to 
North Carolina, 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 gravels. 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

[[Page 37610]]

coast of Long Island and to the north and east.
    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, including a narrow flow that proceeds 
counterclockwise around the perimeter of Rhode Island Sound (RIS) 
likely in association with a tidal mixing front.
    The waters in the vicinity of the Project are transitional waters 
positioned between the continental slope and the coastal environments 
of Rhode Island Sound and Nantucket Sound. The region is generally 
characterized by predominantly mobile sandy substrate, and the 
associated benthic communities are adopted to survive in a dynamic 
environment. The WEAs are composed of a mix of soft and hard bottom 
environments as defined by the dominant sediment grain size and 
composition (Continental Margin Mapping Program [Department of the 
Interior, 2020]; usSEABED (USGS, 2020)).
    The benthic environment of the RI-MA WEA is dominated by sandy 
sediments that ranged from very fine to medium sand; very fine sands 
tend to be more prevalent in deeper, lower energy areas (i.e., the 
southern portion of the MA WEA), whereas coarser sediments, including 
gravels (e.g., patchy cobbles and boulders) were found in shallower 
areas (Bay State Wind, 2019; Deepwater Wind South Fork, LLC, 2019; DWW 
Rev I, LLC, 2020; Stokesbury, 2014; LaFrance et al., 2010; McMaster, 
1960; Popper et al., 2014). The species that inhabit the benthic 
habitats of the OCS are typically described as infaunal species, those 
living in the sediments (e.g., polychaetes, amphipods, mollusks), and 
epifaunal species, those living on the seafloor surface (mobile, e.g., 
sea starts, sand dollars, sand shrimp) or attached to substrates 
(sessile, e.g., barnacles, anemones, tunicates). Further detail on the 
benthic habitats found in the project area, including the results of 
site-specific benthic habitat assessments, can be found within 
Construction and Operations Plan (COP) Volume II-A, Section 5--Results 
Of Biological Surveys and COP Volume II-A Appendices--Appendix II-H 
2016-2020 Benthic Reports.
BILLING CODE 3510-22-P

[[Page 37611]]

[GRAPHIC] [TIFF OMITTED] TP08JN23.000

BILLING CODE 3510-22-C

Detailed Description of Specific Activities

    Below, we provide detailed descriptions of Park City 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.
WTG and ESP Foundation Installation
    Park City Wind proposes to install a maximum of 130 wind turbine 
generator (WTG) and electrical service platform (ESP) positions. Two 
positions may potentially have co-located ESPs (i.e., 1

[[Page 37612]]

WTG and 1 ESP foundation installed at 1 grid position), resulting in 
132 foundations. The WTGs would have a maximum tip height of 357 m 
(1,171 ft) and a maximum penetration depth of 85 m (279 ft). Each 
turbine would be spaced 1 nautical mile (nmi) apart in fixed east-to-
west rows and north-to-south columns to create the 1 nmi by 1 nmi grid 
arrangement. Park City Wind anticipates that the initial WTGs (41-62 
WTGs) would become operational in 2027 after installation is completed 
and all necessary components, such as array cables, ESPs, export cable 
routes, and onshore substations. Park City Wind expects that all 
remaining turbines will be operational by 2028. No more than one 
foundation will be installed at a time (i.e., concurrent/simultaneous 
pile driving of foundations would not occur).
    Phase 1 will include 41 to 62 WTGs and 1 or 2 ESPs for a total of 
42 to 64 foundations. The total number of foundations in Phase 2 
depends upon the final footprint of Phase 1. Phase 2 is expected to 
contain 64 to 88 WTG/ESP foundations (up to 3 of those positions will 
be occupied by ESPs). While only 132 foundations would be permanently 
installed, Park City Wind has accounted for up to 133 pile driving 
events in its take request to account for the instance wherein 
foundation installation began but is unable to be completed due to 
environmental or engineering constraints and the pile is re-driven at 
another position.
    Phase 1 foundation types would be monopiles or jackets while Phase 
2 foundation types include monopiles, jackets, or bottom-frame 
foundations. Jacket foundations require the installation of three to 
four jacket securing piles, known as pin piles. The bottom-frame 
foundation is similar to a conventional jacket foundation, but 
generally has fewer, larger structural tubular members, has a 
triangular space frame, no small-diameter lattice cross-bracing, and a 
single central vertical tubular column. At each foot, the structure 
would be secured to the seafloor using driven piles similar to those 
used by piled jacket foundations or suction buckets. For purposes of 
this analysis, the use of suction buckets to secure bottom-frame 
foundations is not being considered further in this analysis as 
installation of bottom-frame foundations using suction buckets is not 
anticipated to result in noise levels that would cause harassment to 
marine mammals.
    The applicant proposed two construction schedules, A and B. 
Construction schedule A assumes a single 2-year construction scenario. 
Overall, 89 monopile foundations and 2 jacket foundations (8 pin piles) 
would be installed in 2026 over 52 days and 18 monopile foundations and 
24 jacket foundations (96 pin piles) would be installed in 2027 over 35 
days for a total of 87 days of pile driving to install all 133 
foundations. All days would include impact pile driving and a subset 
may include vibratory pile driving and drilling. No more than one 
foundation would be installed at a time (i.e., concurrent/simultaneous 
installation of more than one foundation would not occur). Park City 
Wind anticipates that a maximum of two monopiles or one jacket (up to 
four pin piles) is expected to be installed per day.
    Construction schedule B assumes that all construction would occur 
over a 3-year period (2026-2028). Overall, 55 monopile foundations and 
3 jacket foundations (12 pin piles) would be installed in 2026 over 38 
days, 53 jackets (212 piles) would be installed in 2027 over 53 days, 
and 22 jackets (88 pin piles) would be installed over 22 days in 2028. 
In total, 133 foundations would be installed over 113 days. Similar to 
Schedule A, all days would include impact pile driving and a subset may 
include vibratory pile driving and drilling. Please see Table 2 and 3 
in Park City Wind's March 2023 Application Update Report. Table 2 
provides a summary of Construction Schedule A and B.

                                                 Table 2--Foundation Installation Construction Schedules
                                                                         [Days]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                            Schedule A                                    Schedule B
                       Foundation type                       -------------------------------------------------------------------------------------------
                                                                  2026         2027         Total         2026         2027         2028        Total
--------------------------------------------------------------------------------------------------------------------------------------------------------
Monopiles...................................................           89           18          107            55            0            0           55
Jackets.....................................................            2           24           26             3           53           22           78
No. of Days.................................................           52           35           87            38           53           22          113
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Monopiles would be up to 12 m (39.37 ft) or 13 m (42.7 ft) in 
diameter and could be installed in both Phases 1 and 2. Jacket 
foundations require up to four pin piles and each would have a maximum 
diameter of 4 m (13.1 ft) diameter (see Figures 3-6 in the ITA 
application). When accounting for pre-piling preparatory work and post-
piling activities, installation of a single monopile or jacket pile 
will take approximately 6-13 hours. Park City Wind anticipates at least 
1 hour between monopile installations and 30 minutes between jacket pin 
pile installations. Park City Wind anticipates that a maximum of two 
monopiles or one jacket (up to four pin piles) is expected to be 
installed per day. Pile driving activities could occur within the 8-
month period of May through December.
    A WTG monopile foundation typically consists of a single steel 
tubular section with several sections of rolled steel plate welded 
together and secured to the seabed. Secondary structures on each WTG 
monopile foundation will include a boat landing or alternative means of 
safe access, ladders, a crane, and other ancillary components. A 
typical monopile installation sequence begins with the monopiles 
transported directly to the project area for installation or to the 
construction staging port by an installation vessel or a feeding barge. 
At the foundation location, the main installation vessel upends the 
monopile in a vertical position in the pile gripper mounted on the side 
of the vessel. The hammer is then lifted on top of the pile and pile 
driving commences with a soft-start and proceeds to completion. Piles 
are driven until the target embedment depth is met (up to 50 m), then 
the pile hammer is removed and the monopile is released from the pile 
gripper. Once installation of the monopile is complete, the vessel 
moves to the next installation location.
    Monopiles would be installed using a 5,000 kJ to 6,000 kJ hammer to 
a maximum penetration depth of 40 m (131 ft). Park City Wind estimates 
that a monopile could require up to 6,970 strikes at up to 30.0 blows 
per minute (bpm) to reach full penetration depth. It is expected that 
each monopile installation will last less than 6 hours,

[[Page 37613]]

with most installations anticipated to last between 3-4 hours. Figures 
3-6 in Park City Wind's ITA application provide a conceptual example of 
the WTG support structures (i.e., towers and foundations). WTGs would 
be designed to withstand severe weather conditions anticipated at the 
SWDA (COP Appendix I-E). While major storms, winter nor'easters, and, 
to a lesser extent, hurricanes pass through the SWDA regularly, the 
Project's offshore facilities are designed to withstand such severe 
weather events (COP Volume I).
    Jacket foundations may be used. Once delivered to the SWDA, the 
jacket will be lifted off the transport or installation vessel and 
lowered to the seabed with the correct orientation. The piles will be 
driven to the engineered depth, following the same process described 
above for monopiles. The WTG jacket piles are expected to be pre-piled 
(i.e., the jacket structure will be set on pre-installed piles). Up to 
three ESP jackets are expected to be post-piled (i.e., the jacket is 
placed on the seafloor and piles are subsequently driven through guides 
at the base of each leg). For the ESP post-piled jackets, piling would 
be initiated during daylight hours (no later than 1.5 hours prior to 
civil sunset) and need to continue until all piles are installed due to 
health and safety concerns.
    Jacket foundations would be installed using a 3,500 kJ hammer 
energy pile driving for a 4-m pin pile to reach their maximum 
penetration depth of 50 m (164 ft). There are four pins per jacket 
foundation, Park City Wind estimates that each pin will take up to 
9,805 hammer strikes at up 30.0 bpm to reach full penetration depth 
(Table 1 in the ITA application). Foundation installation would use a 
20-minute soft-start to ensure that the monopile or jacket foundation 
pile remains vertical and to allow any motile marine life to leave the 
area before the pile driving intensity is increased. Jacket foundation 
installation times will vary, but will likely take up to 6 hours per 
pin pile, depending on whether the jacket is pre- or post-piled (Table 
4 ITA application). The bottom-frame foundation (for Phase 2 only) is 
similar to the jacket foundation, with shorter piles and shallower 
penetration. The potential acoustic impact of the bottom-frame 
foundation installation is equivalent to or less than that predicted 
for the jacket foundation. As the design and installation methods for 
bottom-frame foundations would be equivalent to or less than jacket 
foundations, bottom-frame foundations are not carried forward in this 
document.
    During construction of the Project, it may be necessary to start 
pile installation using a vibratory hammer rather than using an impact 
hammer, a technique known as vibratory setting of piles. The vibratory 
method is particularly useful when soft seabed sediments are not 
sufficiently stiff to support the weight of the pile during the initial 
installation, increasing the risk of `pile run' where a pile sinks 
rapidly through seabed sediments. Piles which experience pile run can 
be difficult to recover and pose significant safety risks to the 
personnel and equipment on the construction vessel. The vibratory 
hammer mitigates this risk by forming a hard connection to the pile 
using hydraulic clamps, thereby acting as a lifting/handling tool as 
well as a vibratory hammer. The tool is inserted into the pile on the 
construction vessel deck, and the connection made. The pile is then 
lifted, upended and lowered into position on the seabed using the 
vessel crane. After the pile is lowered into position, vibratory pile 
installation will commence. Vibratory pile installation is a technique 
where piles are driven into soil using a longitudinal vibration motion. 
The vibratory hammer installation method can continue until the pile is 
inserted to a depth that is sufficient to fully support the structure, 
and then the impact hammer can be positioned and operated to complete 
the pile installation. Of the 132 WTG/ESPs, Park City Wind estimates 
approximately 70 total foundations (53 percent) may require vibratory 
hammering before impact hammering. Table 7 and 8 in Park City Wind's 
application provides a breakdown of the number of potential days of 
pile installation, by activity, per month under the maximum design 
scenario for Schedules A and B, respectively.
    Construction schedule A anticipates 20 days of vibratory hammering 
in 2026 and 25 days in 2027 (total 45 days) (Table 2). Construction 
schedule B anticipates 20 days of vibratory hammering in 2026, 25 days 
in 2027, and 9 days in 2028 (total 54 days) (Table 2). Comparisons of 
vibratory pile installation versus impulsive hammer pile installation 
indicate that vibratory pile installation typically produces lower 
amplitude sounds in the marine environment than impact hammer 
installation (Rausche and Beim 2012). The average expected duration of 
vibratory setting is approximately 30 minutes per pile for the Project. 
Due to the small size of the permanent threshold shift (PTS) ranges and 
the mitigation that will be applied during construction, no Level A 
harassment is expected. More information on vibratory pile setting is 
in Section 1.2.2 of the ITA application.
    Drilling is a contingency measure that may be required to remove 
soil and/or boulders from inside the pile in cases of pile refusal 
during installation. A pile refusal can occur if the total frictional 
resistance of the soil becomes too much for the structural integrity of 
the pile and the capability of the impact hammer. Continuing to drive 
in a refused condition can lead to overstress in the pile and potential 
to buckle (tear) the pile material. The use of an offshore drill can 
reduce the frictional resistance by removing the material from inside 
the pile and allowing the continuation of safe pile driving. An 
offshore drill is an equipment piece consisting of a motor and bottom 
hole assembly (BHA). The drill is placed on top of the refused pile 
using the construction vessel crane, and the BHA is lowered down to the 
soil inside the pile. On the bottom face of the BHA is a traditional 
``drill bit,'' which slowly rotates (at 4 or 5 revolutions per minute 
or approximately 0.4 m per hour) and begins to disturb the material 
inside the pile. As the disturbed material mixes with seawater which is 
pumped into the pile, it begins to liquefy. The liquefied material is 
pumped out to a pre-designated location, leaving only muddy seawater 
inside the pile instead of a solid ``soil plug,'' and largely reducing 
the frictional resistance generated by the material inside the pile. 
When enough material has been removed from inside the pile and the 
resistance has reduced sufficiently, the drill is then lifted off the 
pile and recovered to the vessel. The impact hammer is then docked onto 
the pile and impact pile driving commences. It may be necessary to 
remove and replace the drill several times in the driving process to 
achieve sufficiently low frictional resistance to achieve the design 
penetration through impact pile driving. Of the 132 WTG/ESPs, Park City 
Wind estimates 48 foundations (36 percent) may require drilling to 
remove soil and/or boulders from inside the pile that would otherwise 
affect the capability of the impact hammer. Construction schedule A 
anticipates 33 days of drilling in 2026 and 15 days in 2027 (total 48 
days) (Table 2). Construction schedule B anticipates 20 days of 
drilling in 2026, 19 days in 2027, and 9 days in 2028 (total 48 days) 
(Tables 2).
    While pre-piling preparatory work and post-piling activities could 
be ongoing at one foundation position as pile driving is occurring at 
another position, there is no concurrent/

[[Page 37614]]

simultaneous pile driving of foundations planned (see Dates and 
Duration section). Impact pile driving associated with foundation 
installation would be limited to the months of May through December and 
is currently scheduled to be conducted during 2026-2028 (depending 
which construction schedule is done, A or B). Installation of 
foundations is anticipated to result in the take of marine mammals due 
to noise generated during pile driving.
    Park City Wind has proposed to conduct pile driving 24 hours per 
day. Once construction begins, Park City Wind would proceed as rapidly 
as possible, while meeting all required mitigation and monitoring 
measures, to reduce the total duration of construction. NMFS 
acknowledges the benefits of completing construction quickly during 
times when North Atlantic right whales are unlikely to be in the area 
but also recognizes challenges associated with monitoring during 
reduced visibility conditions such as night. Should Park City Wind 
submit a NMFS-approved Alternative Monitoring Plan, pile driving may be 
initiated at night. NMFS intends to condition the final rule, if 
issued, identifying if initiating pile driving at night may occur.
    Installation of the WTG and ESP foundations is anticipated to 
result in the take of marine mammals due to noise generated during pile 
driving and drilling.
HRG Surveys
    High-resolution geophysical site characterization surveys would 
occur annually throughout the 5 years the rule and LOA would be 
effective with duration dependent on the activities occurring in that 
year (i.e., construction versus non-construction year). HRG surveys 
would utilize up to a maximum of three vessels working concurrently in 
different sections of the Lease Area and OECC corridor. Park City Wind 
estimates that no more than 3 years will have HRG surveys and each year 
would have at least 6,000 km surveyed. In total, no more than 18,000 km 
may be surveyed across the 5-years with a total of no more than 225 
vessel days within the Lease Area and along the OECC corridor in water 
depths ranging from 1 m (3.6 ft) to 61.9 m (203 ft). Each day that a 
survey vessel covers 80 km (50 miles) of survey trackline is considered 
vessel day. For example, three vessels operating concurrently on the 
same calendar day, covering 80 km each, would be 3 vessel days.
    HRG surveys would be conducted to identify any seabed debris and to 
support micrositing of the WTG and ESP foundations and cable routes. 
Geophysical survey instruments may include side scan sonar, synthetic 
aperture sonar, single and multibeam echosounders, sub-bottom profilers 
(SBP), and magnetometers/gradiometers, some of which are expected to 
result in the take of marine mammals (LOA Section 1.2.5.). Equipment 
may be mounted to the survey vessel or the Project may use autonomous 
surface vehicles (SFV) to carry out this work. Surveys would occur 
annually, with durations dependent on the activities occurring in that 
year (i.e., construction years versus operational years).
    As summarized previously, HRG surveys will be conducted using up to 
three vessels concurrently. Up to 80 km of survey lines will be 
surveyed per vessel each survey day at approximately 7.4 km/hour (4 
knots) on a 24-hour basis. HRG surveys are anticipated to operate at 
any time of year for 25 days per year, a maximum of 125 days for the 
maximum of the 3 planned years covered under the 5-years of the LOA. Of 
the HRG equipment types proposed for use, the following sources have 
the potential to result in take of marine mammals:
     Medium penetration SBPs (boomers) to map deeper subsurface 
stratigraphy as needed. A boomer is a broad-band sound source operating 
in the 0.2 kHz to 15 kHz frequency range. This system is typically 
mounted on a sled and towed behind the vessel.
     Medium penetration SBPs (sparkers) to map deeper 
subsurface stratigraphy as needed. A sparker creates acoustic pulses 
from 0.05 kHz to 3 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 3 identifies all the representative survey equipment that 
operate below 180 kilohertz (kHz) (i.e., at frequencies that are 
audible and have the potential to disturb marine mammals) that may be 
used in support of planned geophysical survey activities and are likely 
to be detected by marine mammals given the source level, frequency, and 
beamwidth of the equipment. Equipment with operating frequencies above 
180 kHz and equipment that does not have an acoustic output (e.g., 
magnetometers) may 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. In addition, due to the characteristics of 
non-impulsive sources (i.e., Ultra-Short BaseLine (USBL), Innomar, and 
other parametric sub-bottom profilers), take is not anticipated due to 
operating characteristics like very narrow beam width which limit 
acoustic propagation. Therefore, no Level A harassment or B harassment 
can be reasonably expected from the operation of these sources. The 
sources that have the potential to result in harassment to marine 
mammals include boomers and sparkers (Table 3).

                                                 Table 3--Summary of Representative HRG Survey Equipment
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                             Source    Peak source
                                             Representative     Operating  level  (dB   level 0-pk     Pulse     Repetition   Beamwidth    Information
    Equipment type            Name                model         frequency     re 1       (dB re 1    duration    rate  (Hz)   (degrees)       source
                                                                  (kHz)     [mu]Pa m)   [mu]Pa m)      (ms)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Boomer...............  Applied Acoustics   Applied Acoustics       0.2-15         205          212         0.8        \e\ 2         180  CF
                        AA251.              AA251 \a\.
Sparker..............  GeoMarine Geo       SIG ELC 820         \c\ 0.05-3         203          213         3.4        \e\ 1     \d\ 180  CF
                        Spark 2000 (400     Sparker \b\.
                        tip).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Frequency estimated from Figures 14 and 16 in Crocker and Fratantonio (2016). Source levels, beam width, and pulse duration from Table 5 in Crocker
  and Fratantonio (2016) at 300 J.
\b\ SIG ELC 820 has similar operation settings as Geo Spark 2000 (Sect. I.5.1). See Table 9 in Crocker and Fratantonio (2016) source for levels at 5 m
  source depth, 750 J setting.
\c\ Frequency source specifications provided by Vineyard Wind.
\d\ Assumes omnidirectional source.
\e\ Vineyard Wind indicates they will use this repetition rate.


[[Page 37615]]

UXO/MEC Detonations
    Park City Wind anticipates encountering UXO/MECs during Project 
construction. UXO/MECs include explosive munitions (such as bombs, 
shells, mines, torpedoes, etc.) that did not explode when they were 
originally deployed or were intentionally discarded in offshore 
munitions dump sites to avoid land-based detonations. 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.
    For UXO/MECs that are positively identified in proximity to planned 
activities on the seabed, several alternative strategies will be 
considered prior to in-situ UXO/MEC disposal. These may include: (1) 
relocating the activity away from the UXO/MEC (avoidance), (2) physical 
UXO/MEC removal (lift and shift), (3) alternative combustive removal 
technique (low order disposal), (4) cutting the UXO/MEC open to 
apportion large ammunition or deactivate fused munitions (cut and 
capture), or (5) using shaped charges to ignite the explosive materials 
and allow them to burn at a slow rate rather than detonate 
instantaneously (deflagration). Only after these alternatives are 
considered and found infeasible would in-situ high-order UXO/MEC 
detonation be pursued. If detonation is necessary, detonation noise 
could result in the take of marine mammals by Level A harassment and 
Level B harassment.
    Park City wind anticipates that up to 10 UXO/MECs may require 
disposal through high-order detonation and that these detonations would 
occur in 2025 and 2026. To better assess the likelihood of encountering 
UXO/MECs during project construction, Park City Wind is conducting HRG 
surveys 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. However, Park City Wind assumes that up to 10 UXO/MECs 
charges, of up to 454-kg (1,000 pounds; lbs), which is the largest 
charge that is reasonably expected to be encountered (See Estimated 
Take of Marine Mammals for detailed description of UXO/MEC charge 
weights), may require in-situ detonation. Although it is highly 
unlikely that all 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 10 
different days (i.e., only one detonation would occur per day). Park 
City Wind anticipates up to six detonations could occur in 2025 and 
four in 2026. All detonations would occur during daylight hours only 
and would not occur from December 1 through May 31, annually; however, 
NMFS may approve detonating UXO/MECs on a case-by-case basis in 
December and May.
    NMFS concurs with Park City Wind that Levels A and Level B 
harassment are possible for UXO/MEC detonation activities. Auditory 
injury or behavioral harassment may result from exposure to the sounds 
produced by UXO/MEC detonation; no non-auditory injury is anticipated.
Cable Laying and Installation
    Up to five offshore export cables will transmit electricity 
generated by the WTGs to onshore transmission systems in the Town of 
Barnstable, Massachusetts. Underground onshore export cables, located 
primarily within existing roadway layouts, will connect the landfall 
site(s) to one or two new onshore substations in the Town of 
Barnstable, Massachusetts. Grid interconnection cables will then 
connect the Phase 1 onshore substation to the ISO New England (ISO-NE) 
electric grid at Eversource's existing 345 kilovolt substation in West 
Barnstable. Park City Wind intends to install all Phase 2 offshore 
export cables within the same OECC as the Phase 1 cables but will use 
separate landfall sites than Phase 1 in Barnstable. The offshore export 
cables will likely be transported directly to the Offshore Development 
Area in a cable laying vessel, on an ocean-going barge, or on a heavy 
transport vessel (which may also transport the cable laying vessel 
overseas) and installed by the cable laying vessel upon arrival. Vessel 
types under consideration for cable installation activities are 
presented in the COP Volume 1 Table 4.3-1.
    Cable burial operations will occur both in the SWDA for the inter-
array cables connecting the WTGs to the ESPs and in the Offshore Export 
Cable Corridor (OECC) for the cables carrying power from the ESPs to 
the landfall sites. Construction of the OECC and the inter-array cable 
installation would take place in 2026 through 2028 (Table 2). The 
target depth for cable burial is 1.5 m to 2.5 m (5-8 ft). Therefore, 
the seafloor in the direct path of the inter-array, inter-link, and 
offshore export cables within the SWDA will be disturbed from the 
surface to a depth of 1.5 to 2.5 m (5-8 ft). Where sufficient cable 
burial depths cannot be achieved, cable protection would be used. Cable 
laying, cable installation, and cable burial activities planned to 
occur during the construction of the project may include the following: 
jetting (e.g., jet plow or jet trenching); vertical injection; 
leveling; mechanical cutting; plowing (with or without jet-assistance); 
pre-trenching; boulder removal; and controlled flow excavation. During 
construction related activities, including cable laying and 
construction material delivery, dynamic positioning (DP) thrusters may 
be used to maneuver and maintain station. No blasting is proposed for 
cable installation.
    Bottom habitat may also be permanently altered to hard bottom 
substrate through the installation of cable protection (as described in 
Sections 3.2.1.5.4 and 4.2.1.5.4 of BOEM COP Volume I). Potential cable 
protection methods include: rock placement on top of the cables (6.4 cm 
in diameter or larger); Gabion rock bags on top of the cables; concrete 
mattresses; or half-shell pipes or similar (only for cable crossings or 
where the cable is laid on the seafloor). Cable protection will be up 
to 9 m (30 ft) wide. The offshore export cables will likely be 
transported directly to the Offshore Development Area in a cable laying 
vessel, on an ocean-going barge, or on a heavy transport vessel (which 
may also transport the cable laying vessel overseas) and installed by 
the cable laying vessel upon arrival. Phase 1 will consist of two 
offshore export cables with a maximum total length of ~202 km (~109 
nmi). Phase 2 will consist of two or three offshore export cables with 
a maximum total length (assuming three cables) of 356 km (~192 nmi). 
The ends of the offshore export cables will likely be protected using 
protection conduits put in place at the approach to the ESP 
foundation(s). Installation of an offshore export cable is anticipated 
to last approximately 9 months for Phase 1 and approximately 13.5 
months for Phase 2. Cable installation for each Phase may be continuous 
and take up to 2 years. The estimated installation time frame for the 
inter-array cables is over a period of approximately 4-5 months for 
Phase 1 and 9 months for Phase 2.
    The ends of the offshore export cables will likely be protected 
using protection conduits put in place at the approach to the ESP 
foundation(s) (see COP Volume I Figure 3.2-8). This cable entry 
protection system consists of different components of composite 
material and/or cast-iron half-shells with suitable corrosion 
protection, which protect the cables from fatigue and mechanical loads 
as they transition above the seabed and enter the foundation.

[[Page 37616]]

Although a large majority of the cable entry protection system will 
likely lie on top of the monopile scour protection (if used), it will 
likely extend a short distance beyond the edge of the scour protection. 
Additional cable protection may be placed on top of the cable entry 
protection system (within the footprint of the scour protection) to 
secure the cable entry protection system in place and limit movement of 
the cable, which can damage the cable (for specific details see COP 
Volume I section 3.2.1.5.4).
    For Phases 1 and 2, 66 to 132 kilovolt (kV) inter-array cables will 
connect ``strings'' of WTGs to an ESP. The maximum anticipated total 
length of the Phase 1 inter-array cables is approximately 225 km (121 
nmi) and the maximum anticipated total length of the inter-link cable 
is approximately 20 km (11 nmi). The maximum anticipated total length 
of the Phase 2 inter-array cables is approximately 325 km (175 nmi) and 
the maximum anticipated total length of the inter-link cable is 
approximately ~60 km (~32 nmi). The target burial depth of the offshore 
export cables will be at least 1.5-2.5 m (5-8 ft) along their entire 
length. Like the offshore export cables, all inter-array cables and 
inter-link cables will likely be protected with cable entry protection 
systems at the approach to the WTG and ESP foundations.
    Some dredging of the upper portions of sand waves may be required 
prior to cable laying to achieve sufficient burial depth below the 
stable sea bottom; large boulders may also need to be relocated. 
Dredging may be used to remove the upper portions of sand waves within 
the OECC and will be limited only to the extent required to achieve 
adequate cable burial depth during cable installation. Dredging could 
be accomplished by a trailing suction hopper dredge (TSHD) or 
controlled flow excavation.
    The amount of habitat disturbance from the use of jack-up and/or 
anchored vessels, cable installation, and metocean buoy anchors would 
be approximately 4.08 km\2\ (1.58 miles\2\). The total area of 
alteration within the SWDA due to foundation and scour protection 
installation, jack-up and/or anchored vessel use, inter-array and 
inter-link cable installation, potential cable protection (if 
required), and metocean buoy anchors is 5.19 km\2\, (2.00 miles\2\) 
which is 1.1 percent of the maximum size of the SWDA. Metocean buoys 
are small buoys that collect various ocean data. As the noise levels 
generated from cable laying and installation work are low, the 
potential for take of marine mammals to result is discountable. Park 
City Wind is not requesting, and NMFS is not proposing to authorize, 
take associated with cable laying activities. Therefore, cable laying 
activities are not analyzed further in this document.
Site Preparation
    Seabed preparation may be required prior to foundation 
installation, scour protection installation, or cable-laying (see 
Section 3.3.1.2 and 4.3.1.2 of the COP Volume I). This could include 
the removal of large obstructions and/or leveling of the seabed. Large 
boulders along the route may need to be relocated prior to cable 
installation. Some dredging of the upper portions of sand waves may 
also be required prior to cable laying to achieve sufficient burial 
depth below the stable sea bottom. However, depending on bottom 
conditions, water depth, and contractor preferences, other specialty 
techniques may be used in certain areas to ensure sufficient burial 
depth. For monopile and jacket pile installation, seafloor preparation 
will include required boulder clearance and removal of any obstructions 
within the seafloor preparation area at each foundation location. Scour 
protection installation will occur pre- or post-installation and will 
involve a rock dumping vessel placing scour using fall-pipes, side 
dumping, and/or placement using a crane/bucket at each foundation 
location (more details can be found in Park City Wind's COP Volume 1 
Section 3.3.1.2).
    For Phases 1 and 2, a pre-lay grapnel run and pre-lay survey are 
expected to be performed to clear obstructions, such as abandoned 
fishing gear and other marine debris, and inspect the route prior to 
cable laying. A specialized vessel will tow a grapnel rig that hooks 
and recovers obstructions, such as fishing gear, ropes, and wires from 
the seafloor. Boulder clearance may be required in targeted locations 
to clear boulders along the OECC, inter-array cable (IAC) routes, and/
or foundations prior to installation.
    Boulder removal would occur prior to installation and would be 
completed by a support vessel based. It is currently anticipated that 
boulders larger than approximately 0.2-0.3 m (0.7-1 ft) will be avoided 
or relocated outside of the final installation corridor to create an 
installation corridor wide enough to allow the installation tool to 
proceed unobstructed along the seafloor. If there are boulders along 
the final route that cannot be moved, a reasonable buffer of up to 5 m 
(16 ft) could be utilized. Further details on boulder relocation can be 
found in COP Volume 1 Section 3.3.1.3.2.
    Dredging would also occur and be limited to the extent required to 
achieve adequate cable burial depth during cable installation. Where 
dredging is necessary, Park City Wind conservatively assumed that the 
dredge corridor would typically be 15 m (50 ft) wide at the bottom (to 
allow for equipment maneuverability) with approximately 1:3 sideslopes 
for each cable. However, the depth of dredging will vary with the 
height of sand waves and the dimensions of the sideslopes will likewise 
vary with the depth of dredging and sediment conditions. This dredge 
corridor includes up to 1 m (3.3 ft) wide cable installation trench and 
up to 3 m (10 ft) wide temporary disturbance zone from the tracks or 
skids of the cable installation equipment. The average dredge depth is 
approximately 0.5 m (1.6 ft) and may range up to 5.25 m (17 ft) in 
localized areas. The total vertical disturbance within sand waves is up 
to 8 m (26 ft), which includes dredging and cable installation.
    Two installation methods may be used to complete sand leveling 
including Trailing Suction Hopper Dredging (TSHD) and controlled flow 
excavation (CFE). A TSHD can be used in sand waves of most sizes, 
whereas the controlled flow excavation technique is most likely to be 
used in areas where sand waves are less than 2 m (6.6 ft) high. A TSHD 
vessel contains one or more drag arms that extend from the vessel, rest 
on the seafloor, and suction up sediments. Any sediment removed would 
be deposited in the dredged material within the OECC. Bottom dumping of 
dredged material would only occur within sand waves. CFE is a 
contactless dredging tool, providing a method of clearing loose 
sediment below submarine cables, enabling burial. The CFE tool draws in 
seawater from the sides and then jets this water out from a vertical 
down pipe at a specified pressure and volume, which is then positioned 
over the cable alignment, enabling the stream of water to fluidize the 
sands around the cable. This allows the cable to settle into the trench 
under its own weight. Further details on dredging and sand level can be 
found in COP Volume I 3.3.1.3.5.
    NMFS does not expect site preparation work, including boulder 
removal and sand leveling (i.e., dredging), to generate noise levels 
that would cause take of marine mammals. Underwater noise associated 
with these activities 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 project. Sound

[[Page 37617]]

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 those vessels would be comparable to or less than the 
noise produced by DP vessels, so impacts are also expected to be 
similar. Additionally, boulder clearance is a discreet action occurring 
over a short duration resulting in short term direct effects and sound 
produced by boulder clearance equipment would be preceded by, and 
associated with, sound from ongoing vessel noise and would be similar 
in nature.
    NMFS expects that marine mammals would not be exposed to sounds 
levels or durations from seafloor preparation work that would disrupt 
behavioral patterns. Therefore, the potential for take of marine 
mammals to result from these activities is discountable and Park Wind 
did not request, and NMFS does not propose to authorize, any Level A 
harassment or Level B harassment takes associated with seafloor 
preparation work and these activities are not analyzed further in this 
document.
Vessel Operation
    Park City Wind will utilize various types of vessels over the 
course of the 5-year proposed regulations. Park City Wind has 
identified several existing port facilities located in Massachusetts, 
Rhode Island, Connecticut, New York, and/or New Jersey to support 
offshore construction, assembly and fabrication, crew transfer and 
logistics, and other operational activities. In addition, some 
components, materials, and vessels could come from Canadian and 
European ports. A variety of vessels would be used throughout the 
construction activities. These range from crew transportation vessels, 
tugboats, jack-up vessels, cargo ships, and various support vessels 
(Table 4). Details on the vessels, related work, operational speeds, 
and general trip behavior can be found in Table 2 of the ITA 
application and Table 3.3-1 in the COP Volume 1. In addition to 
vessels, helicopters may be used for crew transfer and fast response 
visual inspections and repair activities during both construction and 
operations. It is not possible at this stage of the project to quantify 
the expected use of helicopters and any potential reduction in the 
number of vessel trips.
    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. Construction-related vessel 
activity, including the use of dynamic positioning thrusters, is not 
expected to result in take of marine mammals. Park City Wind did not 
request, and NMFS does not propose to authorize, any take associated 
with vessel activity.
    During construction and operation, crew transfer vessels (CTVs) and 
a service operation vessel (SOV) will be used to conduct maintenance 
activities. Although less likely, if an SOV is not used, several CTVs 
and helicopters would be used to frequently transport crew to and from 
the offshore facilities. Park City Wind has also included potential for 
helicopters to be used when rough weather limits or precludes the use 
of CTVs and during fast response visual inspections and repair 
activities during both construction and operations (COP Volume 1 
Sections 3.3.1.12.1 and 4.3.1.12.1). The total vessels expected for use 
during the Project are in Table 4; more details can be found in Table 2 
of the ITA application.
    Assuming the maximum design scenario for each Phase individually, 
~3,200 total vessel round trips (an average of approximately six round 
trips per day) are expected to occur during offshore construction of 
Phase 1 and ~3,800 total vessel round trips (an average of 
approximately seven round trips per day) are expected to occur during 
offshore construction of Phase 2 (For the purposes of estimating vessel 
trips, tugboats and barges are considered one vessel). Due to the range 
of buildout scenarios for Phases 1 and 2, Park City Wind expects the 
total number of vessel trips from both Phases of New England Wind 
combined to be less than the sum of vessel trips estimated for each 
Phase independently (section 1.1.2 ITA application). Park City Wind 
estimates that, between the 5 major port areas they intend to use, they 
expect an average of 15 round trips per day and 443 round trips per 
month during peak construction (Table 1 ITA application). Throughout 
the entire construction period, they expect an average of 8 round trips 
per day and 215 round trips per month (Table 1 ITA application).

 Table 4--Type and Number of Vessels Anticipated During Construction and
                               Operations
------------------------------------------------------------------------
                                                           Max number of
         Project period                Vessel types           vessels
------------------------------------------------------------------------
All Foundation Installation....  Transport,                           20
                                  Installation, and
                                  Support.
All Foundation Installation....  Crew Transfer..........               3
All Foundation Installation....  Environmental                         8
                                  Monitoring and
                                  Mitigation.
WTG Installation...............  Transport,                           21
                                  Installation, and
                                  Support.
WTG Installation...............  Crew Transfer Vessel...               3
Inter-array Cable Installation.  Transport,                            7
                                  Installation, and
                                  Support.
Inter-array Cable Installation.  Crew Transfer Vessel...               2
ESP Installation...............  Transport,                            9
                                  Installation, and
                                  Support.
ESP Installation...............  Crew Transfer Vessel...               1
Offshore Export Cable            Transport,                           13
 Installation.                    Installation, and
                                  Support.
Offshore Export Cable            Crew Transfer Vessel...               1
 Installation.
All Other Construction           Crew Transfer Vessel...               4
 Activities.
All Other Construction           Transport, Survey, and                4
 Activities.                      Support.
------------------------------------------------------------------------

    NMFS is proposing to require extensive vessel strike avoidance 
measures that would avoid vessel strikes from occurring (see Proposed 
Mitigation section). Park City Wind has not requested, and NMFS is not

[[Page 37618]]

proposing to authorize, take from vessel strikes.
Fisheries and Benthic Monitoring
    Fisheries and benthic monitoring surveys are being 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). Park City Wind 
would conduct trawl net sampling, video surveillance (drop camera), 
plankton (Neuston) net, ventless trap, and tagging surveys. 
Specifically, Park City Wind would conduct seasonal trawl surveys 
following the Northeast Area Monitoring and Assessment Program (NEAMAP) 
survey protocol to sample fish and invertebrates in the SWDA and 
control area. The surveys would be comprised of 200 tows per year 
conducted for 20 minutes at vessel speed of 3.0 knots. The ventless 
trap surveys would follow Massachusetts and Rhode Island Division of 
Marine Fisheries protocol to sample lobster, black sea bass, and Jonah 
crab. Surveys would be conducted twice per month from May to December 
in 30 stations across the SWDA and control areas with 6 lobster traps 
and 1 fish pot at each station. Because the drop camera, tagging 
efforts, and Neuston nets do not have components with which marine 
mammals are likely to interact (i.e., become entangled in or hooked 
by), these activities are not anticipated to result in take of marine 
mammals and will not be discussed further. Only trap and trawl surveys 
have the potential to result in harassment to marine mammals. However, 
Park City Wind would implement mitigation and monitoring measures to 
avoid taking marine mammals, including, but not limited to, monitoring 
for marine mammals before and during trawling activities, not deploying 
or pulling trawl gear in certain circumstances, limiting tow times, and 
fully repairing nets. A full description of mitigation measures can be 
found in the Proposed Mitigation section.
    With the implementation of these measures, Park City Wind does not 
anticipate, and NMFS is not proposing to authorize, take of marine 
mammals incidental to research trap and trawl surveys. Given no take is 
anticipated from these surveys, impacts from fishery surveys will not 
be discussed further in this document (with the exception of the 
description of measures in the Proposed Mitigation section).

Description of Marine Mammals in the Area of Specified Activities

    Thirty-eight marine mammal species under NMFS' jurisdiction have 
geographic ranges within the western North Atlantic OCS (Hayes et al., 
2022). Park City Wind requested take of all 38 species (comprising 38 
stocks) of marine mammals. The majority of takes are requested for only 
17 species; the remaining 22 stocks are considered rare in the project 
area and Park City Wind is requested a limited amount of take for those 
species (e.g., one group size). Sections 3 and 4 of Park City Wind's 
ITA 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 instead of reprinting the information. Additional 
information regarding population trends and threats may be found in 
NMFS's Stock Assessment Reports (SARs), https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments), and 
more general information about these species (e.g., physical and 
behavioral descriptions) may be found on NMFS's website (https://www.fisheries.noaa.gov/find-species).
    Table 5 lists all species and stocks for which take is expected and 
proposed to be authorized for this action and summarizes information 
related to the population or stock, including regulatory status under 
the MMPA and Endangered Species Act (ESA) and potential biological 
removal (PBR) level, where known. The MMPA defines PBR 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'' (16 U.S.C. 1362(20)). 
PBR values are identified in NMFS's SARs. While no mortality is 
anticipated or proposed to be authorized, PBR and annual serious injury 
and mortality from anthropogenic sources are included here as gross 
indicators of the status of the species and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS's stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some stocks, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS's 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, 
unless noted otherwise, use NMFS' 2022 SARs (Hayes et al., 2023) 
available online at https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports.

                              Table 5--Marine Mammal Species That May Occur in the Project Area and Be Taken, by Harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                               Annual
                                                                                             ESA/ MMPA     Stock abundance (CV,              mortalities
           Common name                     Scientific name                  Stock             status;        Nmin, most recent      PBR      or serious
                                                                                          strategic (Y/N)    abundance survey)              injuries (M/
                                                                                                \1\                 \2\                        SI) \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                           Order Artiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenidae:
    North Atlantic right whale...  Eubalaena glacialis............  Western Atlantic....  E,D,Y            338 (0; 332; 2020)..        0.7           8.1
Family Balaenopteridae
 (rorquals):
    Blue whale...................  Balaenoptera musculus..........  Western North         E,D,Y            UNK (UNK, 402, 2019)        0.8             0
                                                                     Atlantic.
    Fin whale....................  Balaenoptera physalus..........  Western North         E,D,Y            6,802 (0.24; 5,573;          11           1.8
                                                                     Atlantic.                              2016).
    Humpback whale...............  Megaptera novaeangliae.........  Gulf of Maine.......  -,-,Y            1,396 (0; 1,380;             22         12.15
                                                                                                            2016).
    Minke whale..................  Balaenoptera acutorostrata.....  Canadian Eastern      -,-,N            21,968 (0.31;               170          10.6
                                                                     Coastal.                               17,002; 2016).
    Sei whale....................  Balaenoptera borealis..........  Nova Scotia.........  E,D,Y            6,292 (1.02; 3,098;         6.2           0.8
                                                                                                            2016).
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 37619]]

 
                                            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 Kogiidae:
    Dwarf sperm whale \4\........  Kogia sima.....................  Western North         -,-,N            7,750 (0.38; 5,689;          46             0
                                                                     Atlantic.                              2016).
    Pygmy sperm whale \4\........  Kogia breviceps................  Western North         -,-,N            7,750 (0.38; 5,689;          46             0
                                                                     Atlantic.                              2016).
Family Ziphiidae:
    Cuvier's beaked whale........  Ziphius cavirostris............  Western North         -,-,N            5,744 (0.36, 4,282,          43           0.2
                                                                     Atlantic.                              2016).
    Blainville's beaked whale....  Mesoplodon densirostris........  Western North         -,-,N            10,107 (0.27, 8,085,         81       \5\ 0.2
                                                                     Atlantic.                              2016).
    Gervais' beaked whale........  Mesoplodon europaeus...........  Western North         -,-,N            5,744 (0.36, 4,282,          81         \5\ 0
                                                                     Atlantic.                              2016).
    Sowerby's beaked whale.......  Mesoplodon bidens..............  Western North         -,-,N            10,107 (0.27, 8,085,         81         \5\ 0
                                                                     Atlantic.                              2016).
    True's beaked whale..........  Mesoplodon mirus...............  Western North         -,-,N            10,107 (0.27, 8,085,         81         \5\ 0
                                                                     Atlantic.                              2016).
    Northern bottlenose whale....  Hyperoodon ampullatus..........  Western North         -,-,N            UNK (UNK, UNK, 2016)        UNK             0
                                                                     Atlantic.
Family Delphinidae:
    Atlantic spotted dolphin.....  Stenella frontalis.............  Western North         -,-,N            39,921 (0.27;               320             0
                                                                     Atlantic.                              32,032; 2016).
    Atlantic white-sided dolphin.  Lagenorhynchus acutus..........  Western North         -,-,N            93,233 (0.71;               544            27
                                                                     Atlantic.                              54,433; 2016).
    Bottlenose dolphin...........  Tursiops truncatus.............  Western North         -,-,N            62,851 (0.23;               519            28
                                                                     Atlantic--Offshore.                    51,914; 2016).
    Clymene dolphin..............  Stenella clymene...............  Western North         -,-,N            4,237 (1.03; 2,071;          21             0
                                                                     Atlantic.                              2016).
    Common dolphin...............  Delphinus delphis..............  Western North         -,-,N            172,897 (0.21;            1,452           390
                                                                     Atlantic.                              145,216; 2016).
    Long-finned pilot whale......  Globicephala melas.............  Western North         -,-,N            39,215 (0.3; 30,627;        306            29
                                                                     Atlantic.                              2016).
    Short-finned pilot whale.....  Globicephala macrorhynchus.....  Western North         -,-,Y            28,924 (0.24,               236           136
                                                                     Atlantic.                              23,637, See SAR).
    Risso's dolphin..............  Grampus griseus................  Western North         -,-,N            35,215 (0.19;               301            34
                                                                     Atlantic.                              30,051; 2016).
    False killer whale...........  Pseudorca crassidens...........  Western North         -,-,N            1,791 (0.56, 1,154,          12             0
                                                                     Atlantic.                              2016).
    Fraser's dolphin.............  Lagenodelphis hosei............  Western North         -,-,N            UNK (UNK, UNK, 2016)        UNK             0
                                                                     Atlantic.
    Killer whale.................  Orcinus orca...................  Western North         -,-,N            UNK (UNK, UNK, 2016)        UNK             0
                                                                     Atlantic.
    Melon-headed whale...........  Peponocephala electra..........  Western North         -,-,N            UNK (UNK, UNK, 2016)        UNK             0
                                                                     Atlantic.
    Pantropical spotted dolphin..  Stenella attenuata.............  Western North         -,D,N            6,593 (0.52, 4,367,          44             0
                                                                     Atlantic.                              2016).
    Pygmy killer whale...........  Feresa attenuata...............  Gulf of Maine/Bay of  -,-,N            UNK (UNK, UNK, 2016)        UNK             0
                                                                     Fundy.
    Rough-toothed dolphin........  Steno bredanensis..............  Western North         -,-,N            136 (1.0, 67, 2016).        0.7             0
                                                                     Atlantic.
    Spinner dolphin..............  Stenella longirostris..........  Western North         -,D,N            4,102 (0.99, 2,045,          20             0
                                                                     Atlantic.                              2016).
    Striped dolphin..............  Halichoerus grypus.............  Western North         -,-,N            67,036 (0.29;               529             0
                                                                     Atlantic.                              52,939; 2016).
    White-beaked dolphin.........  Phoca vitulina.................  Western North         -,-,N            536,016 (0.31;            4,153             0
                                                                     Atlantic.                              415,344; 2016).
Family Phocoenidae (porpoises):
    Harbor porpoise..............  Phocoena phocoena..............  Gulf of Maine/Bay of  -,-,N            95,543 (0.31;               851            16
                                                                     Fundy.                                 74,034; 2016).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals):
    Gray seal \6\................  Halichoerus grypus.............  Western North         -,-,N            27,300 (0.22;             1,389         4,453
                                                                     Atlantic.                              22,785; 2016).
    Harbor seal..................  Phoca vitulina.................  Western North         -,-,N            61,336 (0.08;             1,729           339
                                                                     Atlantic.                              57,637; 2018).
    Harp seal....................  Pagophilus groenlandicus.......  Western North         -,-,N            7.6M (UNK; 7.1M;        426,000       178,573
                                                                     Atlantic.                              2019).
    Hooded seal..................  Cystophora cristata............  Western North         -,-,N            UNK (UNK, UNK, N/A).        UNK         1,680
                                                                     Atlantic.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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 can be found online at www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments assessments. 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). (https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/; Committee on Taxonomy
  (2022)).
\4\ Accounts for both Kogia species.
\5\ Accounts for all Mesoplodon species.
\6\ 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.

    In addition to the species listed in Table 5, the Florida manatees 
(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), 2019). 
However, manatees are managed by the USFWS

[[Page 37620]]

and are not considered further in this document.
    Park City Wind also requested take for beluga whales 
(Delphinapterus leucas), however, beluga whales are so rare in the 
project area that there is no beluga whale stock designated along the 
U.S. Eastern Seaboard as it is a more northerly species. In 2014, a 
beluga whale was observed in Taunton River, Massachusetts, however, 
experts opined that this whale was far from its natural habitat (which 
include arctic and subarctic waters) (Swaintek, 2014). It is not 
anticipated that beluga whales would occur in the project area; 
therefore, beluga whales are not considered further in this document.
    Between October 2011 and June 2015, a total of 76 aerial surveys 
were conducted throughout the MA and RI/MA WEAs (the Project is 
contained within the MA WEA and adjacent to 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 New England Aquarium conducted additional aerial surveys 
throughout the MA and RI/MA WEAs from February 2017 through July 2018 
(38 surveys), October 2018 through August 2019 (40 surveys), and March 
2020 through July 2021 (12 surveys) (Quintana and Kraus, 2019; O'Brien 
et al., 2021a; O'Brien et al., 2021b). As indicated above, 17 species 
and stocks in Table 5 are known to temporally and spatially co-occur 
with the activity. Additionally, 22 stocks are rare in the project 
area. However, Park City Wind has conservatively requested a limited 
amount of take to ensure MMPA compliance in the unlikely event that one 
or more of these rare species are encountered during project activities 
that may result in take (Table 32). Five of the marine mammal species 
for which take is requested are listed as threatened or endangered 
under the ESA: North Atlantic right, blue, fin, sei, and sperm whales.
    In addition to what is included in Sections 3 and 4 of Park City 
Wind's ITA application (https://www.fisheries.noaa.gov/action/incidental-take-authorization-park-city-wind-llc-construction-new-england-wind-offshore-wind), the SARs (https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments), and 
NMFS' website (https://www.fisheries.noaa.gov/species-directory/marine-mammals), we provide further detail below informing the baseline for 
select species (e.g., information regarding current Unusual Mortality 
Events (UME) and known important habitat areas, such as Biologically 
Important Areas (BIAs) (Van Parijs, 2015)). There are no ESA-designated 
critical habitats for any species within the project area (https://www.fisheries.noaa.gov/resource/map/national-esa-critical-habitat-mapper).
    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 May 2023, five UMEs are active. Four of these UMEs are occurring 
along the U.S. Atlantic coast for various marine mammal species. Of 
these, the most relevant to the project area are the North Atlantic 
right whale, humpback whale, and harbor and gray seal UMEs given the 
prevalence of these species in the project area. More information on 
UMEs, including all active, closed, or pending, can be found on NMFS' 
website at https://www.fisheries.noaa.gov/national/marine-life-distress/active-and-closed-unusual-mortality-events.
    Below, we include information for a subset of the species that 
presently have an active or recently closed UME occurring along the 
Atlantic coast or for which there is information available related to 
areas of biological significance. Blue whales have been included due to 
their ESA-listing and not due to any UME or area 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 also a generic 
stock for management purposes. For humpback and sei whales, NMFS 
defines stocks on the basis of feeding locations (i.e., Gulf of Maine 
and Nova Scotia, respectively). However, references to humpback whales 
and sei whales in this document refer to any individuals of the species 
that are found in the project area. Any areas of known biological 
importance (including the BIAs identified in LaBrecque et al., 2015) 
that overlap spatially (or are adjacent) with the project area are 
addressed in the species sections below.

North Atlantic Right Whales

    The North Atlantic right whale has been listed as Endangered since 
the ESA's enactment in 1973. The species was 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; Davis & Brillant, 2019; Knowlton et 
al., 2012; Knowlton et al., 2022; Moore et al., 2021; Sharp et al., 
2019), and a decrease in birth rate (Pettis et al., 2022; Reed et al., 
2022). The Western Atlantic stock is considered depleted under the MMPA 
(Hayes et al., 2022). There is a recovery plan (NMFS, 2005) for the 
North Atlantic right whale, and NMFS completed 5-year reviews of the 
species in 2012, 2017, and 2022 which concluded no change to the 
listing status is warranted.
    Designated by NMFS as a Species in the Spotlight, the North 
Atlantic right whale is considered among the species with the greatest 
risk of extinction in the near future (https://www.fisheries.noaa.gov/topic/endangered-species-conservation/species-in-the-spotlight).
    The North Atlantic right whale population had only a 2.8 percent 
recovery rate between 1990 and 2011 and an overall abundance decline of 
23.5 percent from 2011-2019 (Hayes et al., 2022). Since 2010, the North 
Atlantic right whale population has been in decline (Pace et al., 2017; 
Pace et al., 2021), with a 40 percent decrease in calving rate (Kraus 
et al., 2016; Moore et al., 2021). North Atlantic right whale calving 
rates dropped from 2017 to 2020 with zero births recorded during the 
2017-2018 season. The 2020-2021 calving season had the first 
substantial calving increase in 5 years with 20 calves born followed by 
15 calves during the 2021-2022 calving season. However, mortalities 
continue to outpace births, and best estimates indicate fewer than 70 
reproductively active females remain in the population.
    Critical habitat for North Atlantic right whales is not present in 
the project area. However, the project area both spatially and 
temporally overlaps a portion of the migratory corridor BIA within 
which North Atlantic 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.,

[[Page 37621]]

2015). While the project does not overlap any North Atlantic right 
whale feeding BIAs, it does spatially overlap a more recently described 
important feeding area. North Atlantic 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 (Leiter et al., 
2017; Quintana-Rizzo et al., 2021).
    NMFS' regulations at 50 CFR 224.105 designated Seasonal Management 
Areas (SMAs) for North Atlantic right whales in 2008 (73 FR 60173, 
October 10, 2008). SMAs were developed to reduce the threat of 
collisions between ships and North Atlantic right whales around their 
migratory route and calving grounds. The Block Island SMA is near the 
proposed project area; this SMA is currently active from November 1 
through April 30 of each year and may be used by North Atlantic right 
whales for feeding (although to a lesser extent than the area to the 
east near Nantucket Shoals) and/or migrating. As noted above, NMFS is 
proposing changes to the North Atlantic right whale speed rule (87 FR 
46921, August 1, 2022). Due to the current status of North Atlantic 
right whales and the spatial proximity overlap of the proposed project 
with areas of biological significance, (i.e., a migratory corridor, 
SMA), the potential impacts of the proposed project on North Atlantic 
right whales warrant particular attention.
    North Atlantic right whale presence in the project area is 
predominately seasonal; however, year-round occurrence is documented. 
Abundance is highest in winter with irregular occurrence during summer 
months and similar occurrence rates in spring and fall (O'Brien et al., 
2022; Quintana-Rizzo et al., 2021; Estabrook et al., 2022). Model 
outputs suggest that 23 percent of the North Atlantic right whale 
population is present from December through May, and the mean residence 
time has tripled to an average of 13 days during these months 
(Quintana-Rizzo et al., 2021).
    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 North Atlantic right whale presence across 
their entire habitat range with a decrease in summer months, 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). To describe seasonal trends in North Atlantic 
right whale presence, Estabrook et al. (2022) analyzed North Atlantic 
right whale acoustic detections collected between 2011-2015 during 
winter (January-March), spring (April-June), summer (July-September), 
and autumn (October-December). Winter had the highest presence (75 
percent array-days, n = 193), and summer had the lowest presence (10 
percent array-days, n = 27). Spring and autumn were similar, where 45 
percent (n = 117) and 51 percent (n = 121) of the array-days had 
detections, respectively. Across all years, detections were 
consistently lowest in August and September. In Massachusetts Bay and 
Cape Cod Bay, located outside of the project area, acoustic detections 
of North Atlantic right whales increased in more recent years in both 
the peak season of late winter through early spring and in summer and 
fall, likely reflecting broad-scale regional habitat changes (Charif et 
al., 2020). NMFS' Passive Acoustic Cetacean Map (PACM) contains up-to-
date acoustic data that contributes to our understanding of when and 
where specific whales (including North Atlantic right whales), dolphin, 
and other cetacean species are acoustically detected in the North 
Atlantic. These data support the findings of the aforementioned 
literature.
    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 (Davis et 
al., 2017; Gowan et al., 2019; Krzystan et al., 2018). 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 (Gowan et al., 2019).
    Southern New England waters are a migratory corridor in the spring 
and early winter and a primary feeding habitat for North Atlantic right 
whales during late winter through spring. Right whales feed primarily 
on the copepod Calanus finmarchicus, a species whose availability and 
distribution has changed both spatially and temporally over the last 
decade due to an oceanographic regime shift that has been ultimately 
linked to climate change (Meyer-Gutbrod et al., 2021; Record et al., 
2019; Sorochan et al., 2019). This distribution change in prey 
availability has led to shifts in North Atlantic right whale habitat-
use patterns within the region over the same time period (Davis et al., 
2020; Meyer-Gutbrod et al., 2022; Quintana-Rizzo et al., 2021; O'Brien 
et al., 2022). Since 2010, North Atlantic 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 (Stone et 
al., 2017; Mayo et al., 2018; Ganley et al., 2019; Record et al., 2019; 
Meyer-Gutbrod et al., 2021). The SWDA and OECC are south and east of 
Martha's Vineyard and south and west of Nantucket Islands.
    Since 2017, 98 dead, seriously injured, or sublethally injured or 
ill North Atlantic right whales along the U.S. and Canadian coasts have 
been documented, necessitating a UME declaration and investigation. The 
leading category for the cause of death for this ongoing UME is ``human 
interaction,'' specifically from entanglements or vessel strikes. As of 
May 17, 2023, there have been 36 confirmed mortalities (dead stranded 
or floaters) and 33 seriously injured free-swimming whales for a total 
of 69 whales. Beginning on October 14, 2022, the UME also considers 
animals with sublethal injury or illness bringing the total number of 
whales in the UME to 98. Approximately 42 percent of the population is 
known to be in reduced health (Hamilton et al., 2021) likely 
contributing to smaller body sizes at maturation, making them more 
susceptible to threats and reducing fecundity (Moore et al., 2021; Reed 
et al., 2022; Stewart et al., 2022). More information about the North 
Atlantic right whale UME is available online at https://www.fisheries.noaa.gov/national/marine-life-distress/2017-2023-north-atlantic-right-whale-unusual-mortality-event.

Humpback Whales

    Humpback whales were listed as endangered under the Endangered 
Species Conservation Act (ESCA) in June 1970. In 1973, the ESA replaced 
the ESCA, and humpbacks continued to be listed as endangered. 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

[[Page 37622]]

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 confidence interval (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 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).
    The project area does not overlap any ESA-designated critical 
habitat, BIAs, or other important areas for the humpback whales. A 
humpback whale feeding BIA extends throughout the Gulf of Maine, 
Stellwagen Bank, and Great South Channel from May through December, 
annually (LaBrecque et al., 2015). However, this BIA is located further 
east and north of, and thus, does not overlap, the project area.
    Since January 2016, elevated humpback whale mortalities along the 
Atlantic coast from Maine to Florida led to the declaration of a UME. 
As of May 17, 2023, 191 humpback whales have stranded as part of this 
UME. Partial or full necropsy examinations have been conducted on 
approximately 90 of the known cases. Of the whales examined, about 40 
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. More information is available at 
https://www.fisheries.noaa.gov/national/marine-life-distress/active-and-closed-unusual-mortality-events.

Fin Whales

    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., 
2022). Acoustic detections of fin whale singers augment and confirm 
these visual sighting conclusions for males. 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., 2022).
    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 & MA WEAs 
in the fall and winter months (Kraus et al., 2016), acoustic data 
indicate that this species is present in the RI/MA & MA WEAs during all 
months of the year, although less so in summer months (Morano et al., 
2012; Muirhead et al., 2018; Davis et al., 2020).
    New England waters represent a major feeding ground for fin whales. 
The project area partially overlaps the fin whale feeding BIA (2,933 
km\2\) offshore of Montauk Point, New York from March to October (Hain 
et al., 1992; LaBrecque et al., 2015). A separate larger year-round 
feeding BIA (18,015 km\2\) located far to the northeast in the southern 
Gulf of Maine does not overlap with the project area and would thus not 
be impacted by project activities.

Minke Whales

    Minke whales are common and widely distributed throughout the U.S. 
Atlantic EEZ (Cetacean and Turtle Assessment Program (CETAP), 1982; 
Hayes et al., 2022), although their distribution has a strong seasonal 
component. 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., 2022; Risch et al., 2013). Surveys conducted 
in the RI/MA WEAs 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). Recent surveys 
conducted in the RI/MA WEAs from February 2017 through July 2018, 
October 2018 through August 2019, and March 2020 through July 2021 
documented minke whales as the most common rorqual (baleen whales with 
pleated throat grooves) sighted in the WEAs. Surveys also reported a 
shift in the greatest seasonal abundance of minke whales from spring 
(2017-2018) (Quintana and Kraus, 2018) to summer (2018-2019 and 2020-
2021) (O'Brien et al., 2021a, b).
    There are two minke whale feeding BIAs identified in the southern 
and southwestern section of the Gulf of Maine, including Georges Bank, 
the Great South Channel, Cape Cod Bay and Massachusetts Bay, Stellwagen 
Bank, Cape Anne, and Jeffreys Ledge from March through November, 
annually (LaBrecque et al., 2015). However, these BIAs do not overlap 
the project area as they are located further east and north. A 
migratory route for minke whales transiting between northern feeding 
grounds and southern breeding areas may exist to the east of the 
proposed project area as minke whales may track warmer waters along the 
continental shelf while migrating (Risch et al., 2014).
    From 2017 through 2022, elevated minke whale mortalities detected 
along the Atlantic coast from Maine through South Carolina resulted in 
the declaration of a UME. As of April 14, 2023, a total of 142 minke 
whale mortalities have occurred 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 minke whales examined, so 
more research is needed. More information is available at https://www.fisheries.noaa.gov/national/marine-life-distress/2017-2022-minke-whale-unusual-mortality-event-along-atlantic-coast.

Sei Whale

    The Nova Scotia stock of sei whales can be found in deeper waters 
of the continental shelf edge of the eastern United States and 
northeastward to

[[Page 37623]]

south of Newfoundland (Mitchell, 1975; Hain et al., 1985; Hayes et al., 
2022). During spring and summer, the stock is mainly concentrated in 
northern feeding areas, including the Scotian Shelf (Mitchell and 
Chapman, 1977), the Gulf of Maine, Georges Bank, the Northeast Channel, 
and south of Nantucket (CETAP, 1982; Kraus et al., 2016; Roberts et 
al., 2016; Palka et al., 2017; Cholewiak et al., 2018; Hayes et al., 
2022). Sei whales have been detected acoustically along the Atlantic 
Continental Shelf and Slope from south of Cape Hatteras, North Carolina 
to the Davis Strait, with acoustic occurrence increasing in the mid-
Atlantic region since 2010 (Davis et al., 2020).
    Although their migratory movements are not well understood, sei 
whales are believed to migrate north in June and July to feeding areas 
and south in September and October to breeding areas (Mitchell, 1975; 
CETAP, 1982; Davis et al., 2020). Although sei whales generally occur 
offshore, individuals may also move into shallower, more inshore waters 
(Payne et al., 1990; Halpin et al., 2009; Hayes et al., 2022). A sei 
whale feeding BIA occurs in New England waters from May through 
November (LaBrecque et al., 2015). This BIA is located nearby but not 
within the project area and is not expected to be impacted by the 
Project activities.

Blue Whales

    Blue whales are included within this section due to their ESA-
listing status and not to any active BIA or UME in the project area. 
Blue whales are widely distributed throughout the world's oceans and 
are an ESA-listed species throughout their range. Their Western North 
Atlantic Stock occurs in the western North Atlantic and generally 
ranges from the Arctic to at least mid-latitude waters. Blue whales are 
most frequently sighted in more northerly waters off eastern Canada, 
with the majority of records from the Gulf of St. Lawrence by 
Newfoundland, Canada (Hayes et al., 2019). They often are found near 
the continental shelf edge where upwelling produces concentrations of 
krill, their main prey species (Yochem and Leatherwood, 1985; Fiedler 
et al., 1998; Gill et al., 2011). The blue whale is not common in the 
project area. A 2008 study detected blue whale calls in offshore areas 
of the New York Bight on 28 out of 258 days of recordings (11 percent 
of the days), mostly during winter (Muirhead et al., 2018). Kraus et 
al. (2016) conducted aerial and acoustic surveys between 2011-2015 in 
the MA and RI/MA WEAs and surrounding areas. Blue whales were not 
visually observed and were only sparsely acoustically detected in the 
MA and RI/MA WEAs during winter; the acoustic detection could have been 
due to very distant vocalizations. These data suggest that blue whales 
are rarely, if at all, present in the MA and RI/MA WEAs (Kraus et al., 
2016). Surveys conducted in 2018-2020, did not result in any sightings 
of blue whales in MA and RI/MA WEAs (O'Brien et al., 2021a; O'Brien et 
al., 2021b). However, Park City Wind has requested a small amount of 
take for blue whales on the minimal chance of encounter.
    Much is not known about the blue whale populations, the last 
minimum population abundance was estimated at 402 (Hayes et al., 2023). 
There are insufficient data to determine population trends for blue 
whales. The total level of human caused mortality and serious injury is 
unknown, but it is believed to be insignificant and approaching a zero 
mortality and serious injury rate (Hayes et al., 2019). There are no 
blue whale BIAs or ESA-protected critical habitat identified in the 
project area or along the U.S. Eastern Seaboard. There is no UME for 
blue whales. More information is available at https://www.fisheries.noaa.gov/species/blue-whale.

Pinnipeds

    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 
project area, the populations affected by the UME are the same as those 
potentially affected by the project. Information on this UME is 
available online at https://www.fisheries.noaa.gov/2022-2023-pinniped-unusual-mortality-event-along-maine-coast.
    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 https://www.fisheries.noaa.gov/new-england-mid-atlantic/marine-life-distress/2018-2020-pinniped-unusual-mortality-event-along.

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Current data indicate that not all marine 
mammal species have equal hearing capabilities (e.g., Richardson et 
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect 
this, Southall et al. (2007) recommended that marine mammals be divided 
into functional hearing groups based on directly measured or estimated 
hearing ranges on the basis of available behavioral response data, 
audiograms derived using auditory evoked potential techniques, 
anatomical modeling, and other data. Note that no direct measurements 
of hearing ability have been successfully completed for mysticetes 
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibel (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-frequency cetaceans where the 
lower bound was deemed to be biologically implausible and the lower 
bound from Southall et al. (2007) retained. Marine mammal hearing 
groups and their associated hearing ranges are provided in Table 6.

[[Page 37624]]



                  Table 6--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
            Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen   7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans           150 Hz to 160 kHz.
 (dolphins, toothed whales, beaked
 whales, bottlenose whales).
High-frequency (HF) cetaceans (true    275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 cephalorhynchid, Lagenorhynchus
 cruciger & L. australis).
Phocid pinnipeds (PW) (underwater)     50 Hz to 86 kHz.
 (true seals).
------------------------------------------------------------------------
* 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.
    NMFS notes that in 2019a, 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. (2019a) are identical to NMFS 2018 Revised Technical 
Guidance). When NMFS updates our Technical Guidance, we will be 
adopting the updated Southall et al. (2019a) hearing group 
classification.

Potential Effects of the Specified Activities on Marine Mammals and 
Their Habitat

    This section includes a summary and discussion of the ways that 
components of the specified activity may impact marine mammals and 
their habitat. The Estimated Take of Marine Mammals 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 of Marine Mammals section, 
and the Proposed Mitigation section, to draw conclusions regarding the 
likely impacts of these activities on the reproductive success or 
survivorship of individuals and how those impacts on individuals are 
likely to impact marine mammal species or stocks. 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.
    Park City Wind has requested, and NMFS proposes to authorize, the 
take of marine mammals incidental to the construction activities 
associated with the project area. In their application and Application 
Update Report, Park City Wind presented their analyses of potential 
impacts to marine mammals from the acoustic and explosive sources. NMFS 
both carefully reviewed the information provided by Park City Wind, as 
well as independently reviewed applicable scientific research and 
literature and other information to evaluate the potential effects of 
the Project's activities on marine mammals.
    The proposed activities would result in the construction and 
placement of up to 132 permanent foundations to support WTGs and ESPs 
and seafloor mapping using HRG surveys. Additionally, up to 10 UXO/MEC 
detonations may occur during construction if they cannot be safely 
removed by other means. There are a variety of types and degrees of 
effects to marine mammals, prey species, and habitat that could occur 
as a result of the Project. Below we provide a brief description of the 
types of sound sources that would be generated by the project, the 
general impacts from these types of activities, and an analysis of the 
anticipated impacts on marine mammals from the project, with 
consideration of the proposed mitigation measures.

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 Au and Hastings (2008); Richardson et al. (1995); Urick 
(1983) as well as the Discovery of Sound in the Sea (DOSITS) website at 
https://dosits.org/. 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. 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 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

[[Page 37625]]

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 10 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 considers three metrics. In this proposed rule, 
all decibel levels referenced to 1[mu]Pa.
    Sound exposure level (SEL) represents the total energy in a stated 
frequency band over a stated time interval or event, and considers both 
amplitude and duration of exposure (represented as dB re 1 [mu]Pa\2\-
s). SEL is a cumulative metric; it can be accumulated over a single 
pulse (for pile driving this is often referred to as single-strike SEL; 
SELss), or calculated over periods containing multiple 
pulses (SELcum). Cumulative SEL represents the total energy 
accumulated by a receiver over a defined time window or during an 
event. The SEL metric is useful because it allows sound exposures of 
different durations to be related to one another in terms of total 
acoustic energy. The duration of a sound event and the number of 
pulses, however, should be specified as there is no accepted standard 
duration over which the summation of energy is measured.
    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 PTS (permanent 
threshold shift) and TTS (temporary threshold shift). Peak sound 
pressure 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 impulse metric 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, 2019a) 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 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 the 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

[[Page 37626]]

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. 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, 
such as those in the Project, 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). 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).
    In general, the degree of effect of an acoustic exposure 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. Moreover, any 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 Park City 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.
    Below, we provide additional detail regarding potential impacts on 
marine mammals and their habitat from noise in general, starting with 
hearing impairment, as well as from the specific activities Park City 
Wind plans to conduct, to the degree it is available (noting that there 
is limited information regarding the impacts of offshore wind 
construction on marine mammals).
Hearing 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., 2019a). 
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., 2019a). 
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. However, 
such relationships are assumed to be similar to those in humans and 
other terrestrial mammals. Noise exposure can result in either a 
permanent shift in hearing thresholds from baseline (PTS; a 40 dB 
threshold shift approximates a PTS onset; e.g., Kryter et al., 1966; 
Miller, 1974; Henderson et al., 2008) or a temporary, recoverable shift 
in hearing that returns to baseline (a 6 dB threshold shift 
approximates a TTS onset; e.g., Southall et al., 2019a). 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., 2019a). 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

[[Page 37627]]

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 
depending on the degree of interference of marine mammals hearing. 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 (e.g., for successful mother/calf interactions, consistent 
detection of prey) 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 (Neophocaena 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., 2019a). 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. (2019a) 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, 2016b, 2016c; 
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 Effects
    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 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 (Nowacek et al., 2007; 
DeRuiter et al., 2012 and 2013; Ellison et al., 2012; Gomez et al., 
2016). 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.
    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., 2019a). 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 
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.
    Overall, the variability of responses to acoustic stimuli depends 
on the species receiving the sound, the sound source, and the social, 
behavioral, or environmental contexts of exposure (e.g., DeRuiter et 
al., 2012). For example, Goldbogen et al. (2013a) 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. (2013a) 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[micro]Pa) 
for exposures to 3-4 kHz sonar signals, while deep feeding and non-
feeding whales showed a clear response at exposures at lower received 
levels of sonar and pseudorandom noise. Southall et al. (2011) found 
that blue whales had a different response to sonar exposure depending 
on behavioral state, more pronounced when deep feeding/travel modes 
than when engaged in surface feeding.
    With respect to distance influencing disturbance, DeRuiter et al. 
(2013) examined behavioral responses of Cuvier's beaked whales to mid-
frequency sonar and found that whales responded strongly at low 
received levels (89-127 dB re 1[micro]Pa) by ceasing normal fluking and 
echolocation,

[[Page 37628]]

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[micro]Pa) from distant sonar 
exercises (118 km away) did not elicit such responses, suggesting that 
context may moderate reactions. Thus, distance from the source is an 
important variable in influencing the type and degree of behavioral 
response and this variable is independent of the effect of received 
levels (e.g., DeRuiter et al., 2013; Dunlop et al., 2017a, 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.
    Behavioral change, such as disturbance manifesting in lost foraging 
time, in response to anthropogenic activities is often assumed to 
indicate a biologically significant effect on a population of concern. 
However, individuals may be able to compensate for some types and 
degrees of shifts in behavior, preserving their health and thus their 
vital rates and population dynamics. For example, New et al. (2013) 
developed a model simulating the complex social, spatial, behavioral 
and motivational interactions of coastal bottlenose dolphins in the 
Moray Firth, Scotland, to assess the biological significance of 
increased rate of behavioral disruptions caused by vessel traffic. 
Despite a modeled scenario in which vessel traffic increased from 70 to 
470 vessels a year (a six-fold increase in vessel traffic) in response 
to the construction of a proposed offshore renewables' facility, the 
dolphins' behavioral time budget, spatial distribution, motivations and 
social structure remained unchanged. Similarly, two bottlenose dolphin 
populations in Australia were also modeled over 5 years against a 
number of disturbances (Reed et al., 2020) and results indicate that 
habitat/noise disturbance had little overall impact on population 
abundances in either location, even in the most extreme impact 
scenarios modeled.
    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 fivefold 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.
    The following subsections provide examples of behavioral responses 
that give an idea of the variability in behavioral responses that would 
be expected given the differential sensitivities of marine mammal 
species to sound, contextual factors, 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 
(Eschrichtius robustus) and 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., Malme et al., 1984; Bowles et 
al., 1994; Goold, 1996; Stone et al., 2000; Morton and Symonds, 2002; 
Gailey et al., 2007; D[auml]hne et al., 2013; Russel et al., 2016). 
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, impact pile 
driving) has been documented in the literature with some significant 
variation in the temporal and spatial degree of avoidance and with most 
studies focused on harbor porpoises as 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

[[Page 37629]]

porpoise 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 
porpoise detections during pile driving when compared to 25-48 hours 
before pile driving began, with the magnitude of decline during pile 
driving clearly decreasing with increasing distances to the 
construction site. During the majority of projects, significant 
declines in detections (by at least 20 percent) were found within at 
least 5-10 km of the pile driving site, with declines at up to 20-30 km 
of the pile driving site documented in some cases. 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 (Tougaard et al., 2009; Bailey et al., 2010; D[auml]hne et al., 
2013; Lucke et al., 2012; Haelters et al., 2015).
    While harbor porpoises and seals tend to move several kilometers 
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 porpoise 
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 England during the construction of four wind 
farms (Brasseur et al., 2012; Carroll et al., 2010; Hamre et al., 2011; 
Hastie et al., 2015; Russell et al., 2016). 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 
2 years after construction began (Gilles et al., 2009). Approximately 
10 years after construction of the Nysted wind farm, harbor porpoise 
abundance had not recovered to the original levels previously seen, 
although the 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 for 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 
installing much smaller piles than Park City 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 porpoise and harbor seals documented in 
Europe are likely to occur off Massachusetts. However, we do not 
anticipate any greater severity of response due to harbor porpoise and 
harbor seal habitat use off Massachusetts 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, off Massachusetts, harbor 
porpoises are primarily transient (with higher abundances in winter 
when foundation installation and UXO/MEC detonations would not occur) 
and a very small percentage of the large harbor seal population are 
only seasonally present with no rookeries established. In summary, we 
anticipate that harbor porpoise and harbor seals will likely respond to 
pile driving by moving several kilometers away from the source but 
return to typical habitat use patterns when pile driving ceases.
    Some avoidance behavior of other marine mammal species has been 
documented to be dependent on distance from the source. As described 
above, DeRuiter et al. (2013) noted that distance from a sound source 
may moderate marine mammal reactions in their study of Cuvier's beaked 
whales (an acoustically sensitive species), 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 et 
al. (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, the louder the source level of the playback (i.e., the 
louder the received level), whale 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. Responses to the offshore source 
broadcasting at source levels of 185 and 200 dB, avoidance responses 
were greatly reduced. While there was observed deflection from course, 
in no case did a whale abandon its migratory behavior.
    The signal context of the noise exposure has been shown to play an 
important role in avoidance responses. In a 2007-2008 Bahamas study, 
playback sounds of a potential predator--a killer whale--resulted in a 
similar but more pronounced reaction in beaked whales (an acoustically 
sensitive species), which included longer inter-dive intervals and a 
sustained straight-line departure of more than 20 km from the area 
(Boyd et al., 2008; Southall et al., 2009; Tyack et al., 2011). Park 
City Wind does not anticipate, and NMFS is not proposing to authorize 
take of beaked whales and, moreover, the sounds produced by Park City 
Wind do not have signal characteristics similar to predators. Therefore 
we would not expect such extreme reactions to occur. Southall et al. 
(2011) found that blue whales had a different response to sonar 
exposure depending on behavioral state, more pronounced when deep 
feeding/travel modes than when engaged in surface feeding.
    One potential consequence of behavioral avoidance is the altered 
energetic expenditure of marine mammals because energy is required to 
move and avoid surface vessels or the sound field associated with 
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).

[[Page 37630]]

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.
    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of predators have occurred (Connor and 
Heithaus, 1996; Frid and Dill, 2002). 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). 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. 
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).
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; 
Goldbogen et al., 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, the type and magnitude 
of the response, and the context within which the response occurs 
(e.g., the surrounding environmental and anthropogenic circumstances).
    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, highlighting the 
importance of the sound characteristics in producing a behavioral 
reaction. Although source levels for the proposed pile driving 
activities may exceed the received level of the alerting stimulus 
described by Nowacek et al. (2004), proposed mitigation strategies 
(further described in the Proposed Mitigation section) will reduce the 
severity of response to proposed pile driving activities. Converse to 
the behavior of North Atlantic right whales, Indo-Pacific humpback 
dolphins have been observed to dive 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 seals, illustrating the equivocal nature of 
behavioral effects and 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 cessation of secondary 
indicators of foraging (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., 2019a; 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

[[Page 37631]]

behavior prior to, during, and following exposure to airgun 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 airguns had ceased firing. 
The remaining whales continued to execute foraging dives throughout 
exposure; however, swimming movements during foraging dives were 6 
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.
    Balaenopterid whales exposed to moderate low-frequency 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 an acoustic alarm interrupted their foraging 
dives (Nowacek et al., 2004). Although the received SPLs were similar 
in the latter 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. The source levels of both the proposed 
construction and HRG activities exceed the source levels of the signals 
described by Nowacek et al. (2004) and Croll et al. (2001), and noise 
generated by Park City Wind's activities at least partially 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; 
Southall et al., 2012b, Southall et al., 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 that individual 
fitness and health would be impacted, 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).
Vocalizations and Auditory Masking
    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 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 
below.
    For example, in the presence of potentially masking signals, 
humpback whales and killer whales have been observed to increase the 
length of their songs (Miller et al., 2000; Fristrup et al., 2003; 
Foote et al., 2004) and blue whales increased song production (Di Iorio 
and Clark, 2009), 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). Blackwell et 
al. (2015) showed that whales increased calling rates as soon as airgun 
signals were detectable before ultimately decreasing calling rates at 
higher received levels.
    Sound can disrupt behavior through masking, or interfering with, an 
animal's ability to detect, recognize, or discriminate between acoustic 
signals of interest (e.g., those used for intraspecific communication 
and social interactions, prey detection, predator avoidance, or 
navigation) (Richardson et al., 1995; Erbe and Farmer, 2000; Tyack, 
2000; Erbe et al., 2016). Masking occurs when the receipt of a sound is 
interfered with by another coincident sound at similar frequencies and 
at similar or higher intensity, and may occur whether the sound is 
natural (e.g., snapping shrimp, wind, waves, precipitation) or 
anthropogenic (e.g., shipping, sonar,

[[Page 37632]]

seismic exploration) in origin. The ability of a noise source to mask 
biologically important sounds depends on the characteristics of both 
the noise source and the signal of interest (e.g., signal-to-noise 
ratio, temporal variability, direction), in relation to each other and 
to an animal's hearing abilities (e.g., sensitivity, frequency range, 
critical ratios, frequency discrimination, directional discrimination, 
age, or TTS hearing loss), and existing ambient noise and propagation 
conditions.
    Masking these acoustic signals can disturb the behavior of 
individual animals, groups of animals, or entire populations. Masking 
can lead to behavioral changes including vocal changes (e.g., Lombard 
effect, increasing amplitude, or changing frequency), cessation of 
foraging or lost foraging opportunities, and leaving an area, to both 
signalers and receivers, in an attempt to compensate for noise levels 
(Erbe et al., 2016) or because sounds that would typically have 
triggered a behavior were not detected. In humans, significant masking 
of tonal signals occurs as a result of exposure to noise in a narrow 
band of similar frequencies. As the sound level increases, though, the 
detection of frequencies above those of the masking stimulus decreases 
also. This principle is expected to apply to marine mammals as well 
because of common biomechanical cochlear properties across taxa.
    Therefore, when the coincident (masking) sound is man-made, it may 
be considered harassment when disrupting behavioral patterns. It is 
important to distinguish TTS and PTS, which persist after the sound 
exposure, from masking, which only occurs during the sound exposure. 
Because masking (without resulting in threshold shift) is not 
associated with abnormal physiological function, it is not considered a 
physiological effect, but rather a potential behavioral effect.
    The frequency range of the potentially masking sound is important 
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation 
sounds produced by odontocetes but are more likely to affect detection 
of mysticete communication calls and other potentially important 
natural sounds such as those produced by surf and some prey species. 
The masking of communication signals by anthropogenic noise may be 
considered as a reduction in the communication space of animals (e.g., 
Clark et al., 2009; Matthews et al., 2017) and may result in energetic 
or other costs as animals change their vocalization behavior (e.g., 
Miller et al., 2000; Foote et al., 2004; Parks et al., 2007; Di Iorio 
and Clark, 2009; Holt et al., 2009). Masking can be reduced in 
situations where the signal and noise come from different directions 
(Richardson et al., 1995), through amplitude modulation of the signal, 
or through other compensatory behaviors (Houser and Moore, 2014). 
Masking can be tested directly in captive species (e.g., Erbe, 2008), 
but in wild populations it must be either modeled or inferred from 
evidence of masking compensation. There are few studies addressing 
real-world masking sounds likely to be experienced by marine mammals in 
the wild (e.g., Branstetter et al., 2013; Cholewiak et al., 2018).
    The echolocation calls of toothed whales are subject to masking by 
high-frequency sound. Human data indicate low-frequency sound can mask 
high-frequency sounds (i.e., upward masking). Studies on captive 
odontocetes by Au et al. (1974, 1985, 1993) indicate that some species 
may use various processes to reduce masking effects (e.g., adjustments 
in echolocation call intensity or frequency as a function of background 
noise conditions). There is also evidence that the directional hearing 
abilities of odontocetes are useful in reducing masking at the high-
frequencies these cetaceans use to echolocate, but not at the low-to-
moderate frequencies they use to communicate (Zaitseva et al., 1980). A 
study by Nachtigall and Supin (2008) showed that false killer whales 
adjust their hearing to compensate for ambient sounds and the intensity 
of returning echolocation signals.
    Impacts on signal detection, measured by masked detection 
thresholds, are not the only important factors to address when 
considering the potential effects of masking. As marine mammals use 
sound to recognize conspecifics, prey, predators, or other biologically 
significant sources (Branstetter et al., 2016), it is also important to 
understand the impacts of masked recognition thresholds (often called 
``informational masking''). Branstetter et al. (2016) measured masked 
recognition thresholds for whistle-like sounds of bottlenose dolphins 
and observed that they are approximately 4 dB above detection 
thresholds (energetic masking) for the same signals. Reduced ability to 
recognize a conspecific call or the acoustic signature of a predator 
could have severe negative impacts. Branstetter et al. (2016) observed 
that if ``quality communication'' is set at 90 percent recognition the 
output of communication space models (which are based on 50 percent 
detection) would likely result in a significant decrease in 
communication range.
    As marine mammals use sound to recognize predators (Allen et al., 
2014; Cummings and Thompson, 1971; Cur[eacute] et al., 2015; Fish and 
Vania, 1971), the presence of masking noise may also prevent marine 
mammals from responding to acoustic cues produced by their predators, 
particularly if it occurs in the same frequency band. For example, 
harbor seals that reside in the coastal waters off British Columbia are 
frequently targeted by mammal-eating killer whales. The seals 
acoustically discriminate between the calls of mammal-eating and fish-
eating killer whales (Deecke et al., 2002), a capability that should 
increase survivorship while reducing the energy required to attend to 
all killer whale calls. Similarly, sperm whales (Cur[eacute] et al., 
2016; Isojunno et al., 2016), long-finned pilot whales (Visser et al., 
2016), and humpback whales (Cur[eacute] et al., 2015) changed their 
behavior in response to killer whale vocalization playbacks; these 
findings indicate that some recognition of predator cues could be 
missed if the killer whale vocalizations were masked. The potential 
effects of masked predator acoustic cues depends on the duration of the 
masking noise and the likelihood of a marine mammal encountering a 
predator during the time that detection and recognition of predator 
cues are impeded.
    Redundancy and context can also facilitate detection of weak 
signals. These phenomena may help marine mammals detect weak sounds in 
the presence of natural or manmade noise. Most masking studies in 
marine mammals present the test signal and the masking noise from the 
same direction. The dominant background noise may be highly directional 
if it comes from a particular anthropogenic source such as a ship or 
industrial site. Directional hearing may significantly reduce the 
masking effects of these sounds by improving the effective signal-to-
noise ratio.
    Masking affects both senders and receivers of acoustic signals and, 
at higher levels and longer duration, can potentially have long-term 
chronic effects on marine mammals at the population level as well as at 
the individual level. Low-frequency ambient sound levels have increased 
by as much as 20 dB (more than three times in terms of SPL) in the 
world's ocean from pre-industrial periods, with most of the increase 
from distant commercial shipping (Hildebrand, 2009; Cholewiak et al., 
2018). All anthropogenic sound sources, but especially chronic and

[[Page 37633]]

lower-frequency signals (e.g., from commercial vessel traffic), 
contribute to elevated ambient sound levels, thus intensifying masking.
    In addition to making it more difficult for animals to perceive and 
recognize acoustic cues in their environment, anthropogenic sound 
presents separate challenges for animals that are vocalizing. When they 
vocalize, animals are aware of environmental conditions that affect the 
``active space'' (or communication space) of their vocalizations, which 
is the maximum area within which their vocalizations can be detected 
before it drops to the level of ambient noise (Brenowitz, 2004; Brumm 
et al., 2004; Lohr et al., 2003). Animals are also aware of 
environmental conditions that affect whether listeners can discriminate 
and recognize their vocalizations from other sounds, which is more 
important than simply detecting that a vocalization is occurring 
(Brenowitz, 1982; Brumm et al., 2004; Dooling, 2004; Marten and Marler, 
1977; Patricelli and Blickley, 2006). Most species that vocalize have 
evolved with an ability to make adjustments to their vocalizations to 
increase the signal-to-noise ratio, active space, and recognizability/
distinguishability of their vocalizations in the face of temporary 
changes in background noise (Brumm et al., 2004; Patricelli and 
Blickley, 2006). Vocalizing animals can make adjustments to 
vocalization characteristics such as the frequency structure, 
amplitude, temporal structure, and temporal delivery (repetition rate), 
or ceasing to vocalize.
    Many animals will combine several of these strategies to compensate 
for high levels of background noise. Anthropogenic sounds that reduce 
the signal-to-noise ratio of animal vocalizations, increase the masked 
auditory thresholds of animals listening for such vocalizations, or 
reduce the active space of an animal's vocalizations impair 
communication between animals. Most animals that vocalize have evolved 
strategies to compensate for the effects of short-term or temporary 
increases in background or ambient noise on their songs or calls. 
Although the fitness consequences of these vocal adjustments are not 
directly known in all instances, like most other trade-offs animals 
must make, some of these strategies likely come at a cost (Patricelli 
and Blickley, 2006; Noren et al., 2017; Noren et al., 2020). Shifting 
songs and calls to higher frequencies may also impose energetic costs 
(Lambrechts, 1996).
    Marine mammals are also known to make vocal changes in response to 
anthropogenic noise. In cetaceans, vocalization changes have been 
reported from exposure to anthropogenic noise sources such as sonar, 
vessel noise, and seismic surveying (see the following for examples: 
Gordon et al., 2003; Di Iorio and Clark, 2009; Hatch et al., 2012; Holt 
et al., 2009; Holt et al., 2011; Lesage et al., 1999; McDonald et al., 
2009; Parks et al., 2007; Risch et al., 2012; Rolland et al., 2012), as 
well as changes in the natural acoustic environment (Dunlop et al., 
2014). Vocal changes can be temporary, or can be persistent. For 
example, model simulation suggests that the increase in starting 
frequency for the North Atlantic right whale upcall over the last 50 
years resulted in increased detection ranges between right whales. The 
frequency shift, coupled with an increase in call intensity by 20 dB, 
led to a call detectability range of less than 3 km to over 9 km 
(Tennessen and Parks, 2016). Holt et al. (2009) measured killer whale 
call source levels and background noise levels in the 1 to 40 kHz band 
and reported that the whales increased their call source levels by 1 dB 
SPL for every one dB SPL increase in background noise level. Similarly, 
another study on St. Lawrence River belugas reported a similar rate of 
increase in vocalization activity in response to passing vessels 
(Scheifele et al., 2005). Di Iorio and Clark (2009) showed that blue 
whale calling rates vary in association with seismic sparker survey 
activity, with whales calling more on days with surveys than on days 
without surveys. They suggested that the whales called more during 
seismic survey periods as a way to compensate for the elevated noise 
conditions.
    In some cases, these vocal changes may have fitness consequences, 
such as an increase in metabolic rates and oxygen consumption, as 
observed in bottlenose dolphins when increasing their call amplitude 
(Holt et al., 2015). A switch from vocal communication to physical, 
surface-generated sounds such as pectoral fin slapping or breaching was 
observed for humpback whales in the presence of increasing natural 
background noise levels, indicating that adaptations to masking may 
also move beyond vocal modifications (Dunlop et al., 2010).
    While these changes all represent possible tactics by the sound-
producing animal to reduce the impact of masking, the receiving animal 
can also reduce masking by using active listening strategies such as 
orienting to the sound source, moving to a quieter location, or 
reducing self-noise from hydrodynamic flow by remaining still. The 
temporal structure of noise (e.g., amplitude modulation) may also 
provide a considerable release from masking through comodulation 
masking release (a reduction of masking that occurs when broadband 
noise, with a frequency spectrum wider than an animal's auditory filter 
bandwidth at the frequency of interest, is amplitude modulated) 
(Branstetter and Finneran, 2008; Branstetter et al., 2013). Signal type 
(e.g., whistles, burst-pulse, sonar clicks) and spectral 
characteristics (e.g., frequency modulated with harmonics) may further 
influence masked detection thresholds (Branstetter et al., 2016; 
Cunningham et al., 2014).
    Masking is more likely to occur in the presence of broadband, 
relatively continuous noise sources, such as vessels. Several studies 
have shown decreases in marine mammal communication space and changes 
in behavior as a result of the presence of vessel noise. For example, 
right whales were observed to shift the frequency content of their 
calls upward while reducing the rate of calling in areas of increased 
anthropogenic noise (Parks et al., 2007) as well as increasing the 
amplitude (intensity) of their calls (Parks, 2009; Parks et al., 2011). 
Clark et al. (2009) observed that right whales' communication space 
decreased by up to 84 percent in the presence of vessels. Cholewiak et 
al. (2018) also observed loss in communication space in Stellwagen 
National Marine Sanctuary for North Atlantic right whales, fin whales, 
and humpback whales with increased ambient noise and shipping noise. 
Although humpback whales off Australia did not change the frequency or 
duration of their vocalizations in the presence of ship noise, their 
source levels were lower than expected based on source level changes to 
wind noise, potentially indicating some signal masking (Dunlop, 2016). 
Multiple delphinid species have also been shown to increase the minimum 
or maximum frequencies of their whistles in the presence of 
anthropogenic noise and reduced communication space (for examples see: 
Holt et al., 2009; Holt et al., 2011; Gervaise et al., 2012; Williams 
et al., 2013; Hermannsen et al., 2014; Papale et al., 2015; Liu et al., 
2017). While masking impacts are not a concern from lower intensity, 
higher frequency HRG surveys, some degree of masking would be expected 
in the vicinity of turbine pile driving and concentrated support vessel 
operation. However, pile driving is an intermittent sound and would not 
be continuous throughout a day.
Habituation and Sensitization
    Habituation can occur when an animal's response to a stimulus wanes

[[Page 37634]]

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; 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; Houser et al., 2013b; 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).
    Stone (2015) reported data from at-sea observations during 1,196 
airgun surveys from 1994 to 2010. When large arrays of airguns 
(considered to be 500 in 3 or more) were firing, lateral displacement, 
more localized avoidance, or other changes in behavior were evident for 
most odontocetes. However, significant responses to large arrays were 
found only for the minke whale and fin whale. Behavioral responses 
observed included changes in swimming or surfacing behavior with 
indications that cetaceans remained near the water surface at these 
times. Behavioral observations of gray whales during an airgun survey 
monitored whale movements and respirations pre-, during-, and post-
seismic survey (Gailey et al., 2016). Behavioral state and water depth 
were the best `natural' predictors of whale movements and respiration 
and after considering natural variation, none of the response variables 
were significantly associated with survey or vessel sounds. Many 
delphinids approach low-frequency airgun source vessels with no 
apparent discomfort or obvious behavioral change (e.g., Barkaszi et 
al., 2012), indicating the importance of frequency output in relation 
to the species' hearing sensitivity.
Physiological Responses
    An animal's perception of a threat may be sufficient to trigger 
stress responses consisting of some combination of behavioral 
responses, autonomic nervous system responses, neuroendocrine 
responses, or immune responses (e.g., Seyle, 1950; Moberg, 2000). In 
many cases, an animal's first and sometimes most economical (in terms 
of energetic costs) response is behavioral avoidance of the potential 
stressor. Autonomic nervous system responses to stress typically 
involve changes in heart rate, blood pressure, and gastrointestinal 
activity. These responses have a relatively short duration and may or 
may not have a significant long-term effect on an animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha, 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficiently to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker, 2000; 
Romano et al., 2002b) and, more rarely, studied in wild populations 
(e.g., Lusseau and Bejder, 2007; Romano et al., 2002a; Rolland et al., 
2012). For example, Rolland et al. (2012) found that noise reduction 
from reduced ship traffic in the Bay of Fundy was associated with 
decreased stress in North Atlantic right whales.
    These and other studies lead to a reasonable expectation that some 
marine mammals will experience physiological stress responses upon 
exposure to acoustic stressors and that it is possible that some of 
these would be classified as ``distress.'' In addition, any animal 
experiencing TTS would likely also experience stress responses (NRC, 
2003, 2017).
    Respiration naturally varies with different behaviors and 
variations in 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 of the same acoustic alarm to a 
striped dolphin under the same conditions did not elicit a response 
(Kastelein et al., 2006a), again highlighting the importance in 
understanding species differences in the tolerance of underwater noise 
when determining the potential for impacts resulting from anthropogenic 
sound exposure.
Stranding
    The definition for a stranding under title IV of the MMPA is that 
(A) a marine mammal is dead and is (i) on a beach or shore of the 
United States; or (ii) in waters under the jurisdiction of the

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United States (including any navigable waters); or (B) a marine mammal 
is alive and is (i) on a beach or shore of the United States and is 
unable to return to the water; (ii) on a beach or shore of the United 
States and, although able to return to the water, is in need of 
apparent medical attention; or (iii) in the waters under the 
jurisdiction of the United States (including any navigable waters), but 
is unable to return to its natural habitat under its own power or 
without assistance (16 U.S.C. 1421h).
    Marine mammal strandings have been linked to a variety of causes, 
such as illness from exposure to infectious agents, biotoxins, or 
parasites; starvation; unusual oceanographic or weather events; or 
anthropogenic causes including fishery interaction, ship strike, 
entrainment, entrapment, sound exposure, or combinations of these 
stressors sustained concurrently or in series. There have been multiple 
events worldwide in which marine mammals (primarily beaked whales, or 
other deep divers) have stranded coincident with relatively nearby 
activities utilizing loud sound sources (primarily military training 
events), and five in which mid-frequency active sonar has been more 
definitively determined to have been a contributing factor.
    There are multiple theories regarding the specific mechanisms 
responsible for marine mammal strandings caused by exposure to loud 
sounds. One primary theme is the behaviorally mediated responses of 
deep-diving species (odontocetes), in which their startled response to 
an acoustic disturbance (1) affects ascent or descent rates, the time 
they stay at depth or the surface, or other regular dive patterns that 
are used to physiologically manage gas formation and absorption within 
their bodies, such that the formation or growth of gas bubbles damages 
tissues or causes other injury, or (2) results in their flight to 
shallow areas, enclosed bays, or other areas considered ``out of 
habitat,'' in which they become disoriented and physiologically 
compromised. For more information on marine mammal stranding events and 
potential causes, please see the Mortality and Stranding section of 
NMFS Proposed Incidental Take Regulations for the Navy's Training and 
Testing Activities in the Hawaii-Southern California Training and 
Testing Study Area (50 CFR part 218, Volume 83, No. 123, June 26, 
2018).
    The construction activities proposed by Park City Wind (i.e., pile 
driving, drilling, UXO/MEC detonation) do not inherently have the 
potential to result in marine mammal strandings. While vessel strikes 
and UXO/MEC detonation could kill or injure a marine mammals (which may 
eventually strand), the required mitigation measures would reduce the 
potential for take from these activities to de minimus levels (see 
Proposed Mitigation section for more details). As described above, no 
mortality or serious injury is anticipated or proposed to be authorized 
from any Project activities.
    Of the strandings documented to date worldwide, NMFS is not aware 
of any being attributed to pile driving, a single UXO/MEC detonation of 
the charge weights proposed here, or the types of HRG equipment 
proposed for use during the Project. Recently, there has been 
heightened interest in HRG surveys and their potential role in recent 
marine mammals strandings along the U.S. east coast. HRG surveys 
involve the use of certain sources to image the ocean bottom, which are 
very different from seismic airguns used in oil and gas surveys or 
tactical military sonar, in that they produce much smaller impact 
zones. Marine mammals may respond to exposure to these sources by, for 
example, avoiding the immediate area, which is why offshore wind 
developers have authorization to allow for Level B (behavioral) 
harassment, including Park City Wind. However, because of the 
combination of lower source levels, higher frequency, narrower beam-
width (for some sources), and other factors, the area within which a 
marine mammal might be expected to be behaviorally disturbed by HRG 
sources is much smaller (by orders of magnitude) than the impact areas 
for seismic airguns or the military sonar with which a small number of 
marine mammal have been causally associated. Specifically, estimated 
harassment zones for HRG surveys are typically less than 200m (such as 
those associated with the Project), while zones for military mid-
frequency active sonar or seismic airgun surveys typically extend for 
several kms ranging up to 10s of km. Further, because of this much 
smaller ensonified area, any marine mammal exposure to HRG sources is 
reasonably expected to be at significantly lower levels and shorter 
duration (associated with less severe responses), and there is no 
evidence suggesting, or reason to speculate, that marine mammals 
exposed to HRG survey noise are likely to be injured, much less strand, 
as a result. Last, all but one of the small number of marine mammal 
stranding events that have been causally associated with exposure to 
loud sound sources have been deep-diving toothed whale species (not 
mysticetes), which are known to respond differently to loud sounds.

Potential Effects of Disturbance on Marine Mammal Fitness

    The different ways that marine mammals respond to sound are 
sometimes indicators of the ultimate effect that exposure to a given 
stimulus will have on the well-being (survival, reproduction, etc.) of 
an animal. There are numerous data relating the exposure of terrestrial 
mammals from sound to effects on reproduction or survival, and data for 
marine mammals continues to grow. Several authors have reported that 
disturbance stimuli may cause animals to abandon nesting and foraging 
sites (Sutherland and Crockford, 1993); may cause animals to increase 
their activity levels and suffer premature deaths or reduced 
reproductive success when their energy expenditures exceed their energy 
budgets (Daan et al., 1996; Feare, 1976; Mullner et al., 2004); or may 
cause animals to experience higher predation rates when they adopt 
risk-prone foraging or migratory strategies (Frid and Dill, 2002). Each 
of these studies addressed the consequences of animals shifting from 
one behavioral state (e.g., resting or foraging) to another behavioral 
state (e.g., avoidance or escape behavior) because of human disturbance 
or disturbance stimuli.
    Attention is the cognitive process of selectively concentrating on 
one aspect of an animal's environment while ignoring other things 
(Posner, 1994). Because animals (including humans) have limited 
cognitive resources, there is a limit to how much sensory information 
they can process at any time. The phenomenon called ``attentional 
capture'' occurs when a stimulus (usually a stimulus that an animal is 
not concentrating on or attending to) ``captures'' an animal's 
attention. This shift in attention can occur consciously or 
subconsciously (for example, when an animal hears sounds that it 
associates with the approach of a predator) and the shift in attention 
can be sudden (Dukas, 2002; van Rij, 2007). Once a stimulus has 
captured an animal's attention, the animal can respond by ignoring the 
stimulus, assuming a ``watch and wait'' posture, or treat the stimulus 
as a disturbance and respond accordingly, which includes scanning for 
the source of the stimulus or ``vigilance'' (Cowlishaw et al., 2004).
    Vigilance is an adaptive behavior that helps animals determine the 
presence or absence of predators, assess their distance from 
conspecifics, or to attend cues from prey (Bednekoff and Lima, 1998; 
Treves, 2000). Despite those

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benefits, however, vigilance has a cost of time; when animals focus 
their attention on specific environmental cues, they are not attending 
to other activities such as foraging or resting. These effects have 
generally not been demonstrated for marine mammals, but studies 
involving fish and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (Saino, 1994; 
Beauchamp and Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 
2011). Animals will spend more time being vigilant, which may translate 
to less time foraging or resting, when disturbance stimuli approach 
them more directly, remain at closer distances, have a greater group 
size (e.g., multiple surface vessels), or when they co-occur with times 
that an animal perceives increased risk (e.g., when they are giving 
birth or accompanied by a calf).
    The primary mechanism by which increased vigilance and disturbance 
appear to affect the fitness of individual animals is by disrupting an 
animal's time budget and, as a result, reducing the time they might 
spend foraging and resting (which increases an animal's activity rate 
and energy demand while decreasing their caloric intake/energy). In a 
study of northern resident killer whales off Vancouver Island, exposure 
to boat traffic was shown to reduce foraging opportunities and increase 
traveling time (Holt et al., 2021). A simple bioenergetics model was 
applied to show that the reduced foraging opportunities equated to a 
decreased energy intake of 18 percent while the increased traveling 
incurred an increased energy output of 3-4 percent, which suggests that 
a management action based on avoiding interference with foraging might 
be particularly effective.
    On a related note, many animals perform vital functions, such as 
feeding, resting, traveling, and socializing, on a diel cycle (24-hr 
cycle). Behavioral reactions to noise exposure (such as disruption of 
critical life functions, displacement, or avoidance of important 
habitat) are more likely to be significant for fitness if they last 
more than one diel cycle or recur on subsequent days (Southall et al., 
2007). Consequently, a behavioral response lasting less than 1 day and 
not recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). It is important to note the difference between behavioral 
reactions lasting or recurring over multiple days and anthropogenic 
activities lasting or recurring over multiple days. For example, just 
because certain activities last for multiple days does not necessarily 
mean that individual animals will be either exposed to those activity-
related stressors (i.e., sonar) for multiple days or further exposed in 
a manner that would result in sustained multi-day substantive 
behavioral responses. However, special attention is warranted where 
longer-duration activities overlay areas in which animals are known to 
congregate for longer durations for biologically important behaviors.
    There are few studies that directly illustrate the impacts of 
disturbance on marine mammal populations. Lusseau and Bejder (2007) 
present data from three long-term studies illustrating the connections 
between disturbance from whale-watching boats and population-level 
effects in cetaceans. In Shark Bay, Australia, the abundance of 
bottlenose dolphins was compared within adjacent control and tourism 
sites over three consecutive 4.5-year periods of increasing tourism 
levels. Between the second and third time periods, in which tourism 
doubled, dolphin abundance decreased by 15 percent in the tourism area 
and did not change significantly in the control area. In Fiordland, New 
Zealand, two populations (Milford and Doubtful Sounds) of bottlenose 
dolphins with tourism levels that differed by a factor of seven were 
observed and significant increases in traveling time and decreases in 
resting time were documented for both. Consistent short-term avoidance 
strategies were observed in response to tour boats until a threshold of 
disturbance was reached (average 68 minutes between interactions), 
after which the response switched to a longer-term habitat displacement 
strategy. For one population, tourism only occurred in a part of the 
home range. However, tourism occurred throughout the home range of the 
Doubtful Sound population and once boat traffic increased beyond the 
68-minute threshold (resulting in abandonment of their home range/
preferred habitat), reproductive success drastically decreased 
(increased stillbirths) and abundance decreased significantly (from 67 
to 56 individuals in a short period).
    In order to understand how the effects of activities may or may not 
impact species and stocks of marine mammals, it is necessary to 
understand not only what the likely disturbances are going to be but 
how those disturbances may affect the reproductive success and 
survivorship of individuals and then how those impacts to individuals 
translate to population-level effects. Following on the earlier work of 
a committee of the U.S. National Research Council (NRC, 2005), New et 
al. (2014), in an effort termed the Potential Consequences of 
Disturbance (PCoD), outline an updated conceptual model of the 
relationships linking disturbance to changes in behavior and 
physiology, health, vital rates, and population dynamics. This 
framework is a four-step process progressing from changes in individual 
behavior and/or physiology, to changes in individual health, then vital 
rates, and finally to population-level effects. In this framework, 
behavioral and physiological changes can have direct (acute) effects on 
vital rates, such as when changes in habitat use or increased stress 
levels raise the probability of mother-calf separation or predation; 
indirect and long-term (chronic) effects on vital rates, such as when 
changes in time/energy budgets or increased disease susceptibility 
affect health, which then affects vital rates; or no effect to vital 
rates (New et al., 2014).
    Since the PCoD general framework was outlined and the relevant 
supporting literature compiled, multiple studies developing state-space 
energetic models for species with extensive long-term monitoring (e.g., 
southern elephant seals, North Atlantic right whales, Ziphiidae beaked 
whales, and bottlenose dolphins) have been conducted and can be used to 
effectively forecast longer-term, population-level impacts from 
behavioral changes. While these are very specific models with very 
specific data requirements that cannot yet be applied broadly to 
project-specific risk assessments for the majority of species, they are 
a critical first step towards being able to quantify the likelihood of 
a population level effect. Since New et al. (2014), several 
publications have described models developed to examine the long-term 
effects of environmental or anthropogenic disturbance of foraging on 
various life stages of selected species (e.g., sperm whale, Farmer et 
al. (2018); California sea lion, McHuron et al. (2018); blue whale, 
Pirotta et al. (2018a); humpback whale, Dunlop et al. (2021)). These 
models continue to add to refinement of the approaches to the PCoD 
framework. Such models also help identify what data inputs require 
further investigation. Pirotta et al. (2018b) provides a review of the 
PCoD framework with details on each step of the process and approaches 
to applying real data or simulations to achieve each step.
    Despite its simplicity, there are few complete PCoD models 
available for any marine mammal species due to a lack of data available 
to parameterize many of the steps. To date, no PCoD model has been 
fully parameterized with empirical

[[Page 37637]]

data (Pirotta et al., 2018a) due to the fact they are data intensive 
and logistically challenging to complete. Therefore, most complete PCoD 
models include simulations, theoretical modeling, and expert opinion to 
move through the steps. For example, PCoD models have been developed to 
evaluate the effect of wind farm construction on the North Sea harbor 
porpoise populations (e.g., King et al., 2015; Nabe-Nielsen et al., 
2018). These models include a mix of empirical data, expert elicitation 
(King et al., 2015) and simulations of animals' movements, energetics, 
and/or survival (New et al., 2014; Nabe-Nielsen et al., 2018).
    PCoD models may also be approached in different manners. Dunlop et 
al. (2021) modeled migrating humpback whale mother-calf pairs in 
response to seismic surveys using both a forwards and backwards 
approach. While a typical forwards approach can determine if a stressor 
would have population-level consequences, Dunlop et al. demonstrated 
that working backwards through a PCoD model can be used to assess the 
``worst case'' scenario for an interaction of a target species and 
stressor. This method may be useful for future management goals when 
appropriate data becomes available to fully support the model. In 
another example, harbor porpoise PCoD model investigating the impact of 
seismic surveys on harbor porpoise included an investigation on 
underlying drivers of vulnerability. Harbor porpoise movement and 
foraging were modeled for baseline periods and then for periods with 
seismic surveys as well; the models demonstrated that temporal (i.e., 
seasonal) variation in individual energetics and their link to costs 
associated with disturbances was key in predicting population impacts 
(Gallagher et al., 2021).
    Behavioral change, such as disturbance manifesting in lost foraging 
time, in response to anthropogenic activities is often assumed to 
indicate a biologically significant effect on a population of concern. 
However, as described above, individuals may be able to compensate for 
some types and degrees of shifts in behavior, preserving their health 
and thus their vital rates and population dynamics. For example, New et 
al. (2013) developed a model simulating the complex social, spatial, 
behavioral and motivational interactions of coastal bottlenose dolphins 
in the Moray Firth, Scotland, to assess the biological significance of 
increased rate of behavioral disruptions caused by vessel traffic. 
Despite a modeled scenario in which vessel traffic increased from 70 to 
470 vessels a year (a six-fold increase in vessel traffic) in response 
to the construction of a proposed offshore renewables' facility, the 
dolphins' behavioral time budget, spatial distribution, motivations, 
and social structure remain unchanged. Similarly, two bottlenose 
dolphin populations in Australia were also modeled over 5 years against 
a number of disturbances (Reed et al., 2020), and results indicated 
that habitat/noise disturbance had little overall impact on population 
abundances in either location, even in the most extreme impact 
scenarios modeled.
    By integrating different sources of data (e.g., controlled exposure 
data, activity monitoring, telemetry tracking, and prey sampling) into 
a theoretical model to predict effects from sonar on a blue whale's 
daily energy intake, Pirotta et al. (2021) found that tagged blue 
whales' activity budgets, lunging rates, and ranging patterns caused 
variability in their predicted cost of disturbance. This method may be 
useful for future management goals when appropriate data becomes 
available to fully support the model. Harbor porpoise movement and 
foraging were modeled for baseline periods and then for periods with 
seismic surveys as well; the models demonstrated that the seasonality 
of the seismic activity was an important predictor of impact (Gallagher 
et al., 2021).
    In their Table 1, Keen et al. (2021) summarize the emerging themes 
in PCoD models that should be considered when assessing the likelihood 
and duration of exposure and the sensitivity of a population to 
disturbance (see Table 1 from Keen et al., 2021, below). The themes are 
categorized by life history traits (movement ecology, life history 
strategy, body size, and pace of life), disturbance source 
characteristics (overlap with biologically important areas, duration 
and frequency, and nature and context), and environmental conditions 
(natural variability in prey availability and climate change). Keen et 
al. (2021) then summarize how each of these features influence an 
assessment, noting, for example, that individual animals with small 
home ranges have a higher likelihood of prolonged or year-round 
exposure, that the effect of disturbance is strongly influenced by 
whether it overlaps with biologically important habitats when 
individuals are present, and that continuous disruption will have a 
greater impact than intermittent disruption.
    Nearly all PCoD studies and experts agree that infrequent exposures 
of a single day or less are unlikely to impact individual fitness, let 
alone lead to population level effects (Booth et al., 2016; Booth et 
al., 2017; Christiansen and Lusseau 2015; Farmer et al., 2018; Wilson 
et al., 2020; Harwood and Booth 2016; King et al., 2015; McHuron et 
al., 2018; National Academies of Sciences, Engineering, and Medicine 
(NAS), 2017; New et al., 2014; Pirotta et al., 2018a; Southall et al., 
2007; Villegas-Amtmann et al., 2015). As described through this 
proposed rule, NMFS expects that any behavioral disturbance that would 
occur due to animals being exposed to construction activity would be of 
a relatively short duration, with behavior returning to a baseline 
state shortly after the acoustic stimuli ceases or the animal moves far 
enough away from the source. Given this, and NMFS' evaluation of the 
available PCoD studies, and the required mitigation discussed later, 
any such behavioral disturbance resulting from Park City Wind's 
activities is not expected to impact individual animals' health or have 
effects on individual animals' survival or reproduction, thus no 
detrimental impacts at the population level are anticipated. Marine 
mammals may temporarily avoid the immediate area but are not expected 
to permanently abandon the area or their migratory or foraging 
behavior. Impacts to breeding, feeding, sheltering, resting, or 
migration are not expected nor are shifts in habitat use, distribution, 
or foraging success.

Potential Effects From Explosive Sources

    With respect to the noise from underwater explosives, the same 
acoustic-related impacts described above apply and are not repeated 
here. Noise from explosives can cause hearing impairment if an animal 
is close enough to the sources; however, because noise from an 
explosion is discrete, lasting less than approximately 1 second, no 
behavioral impacts below the TTS threshold are anticipated considering 
that Park City Wind would not detonate more than 1 UXO/MEC per day and 
only 10 during the life of the proposed rule. This section focuses on 
the pressure-related impacts of underwater explosives, including 
physiological injury and mortality.
    Underwater explosive detonations send a shock wave and sound energy 
through the water and can release gaseous by-products, create an 
oscillating bubble, or cause a plume of water to shoot up from the 
water surface. The shock wave and accompanying noise are of most 
concern to marine animals. Depending on the intensity of the shock wave 
and size, location, and depth of the animal, an animal can be injured, 
killed, suffer non-lethal physical effects, experience

[[Page 37638]]

hearing related effects with or without behavioral responses, or 
exhibit temporary behavioral responses or tolerance from hearing the 
blast sound. Generally, exposures to higher levels of impulse and 
pressure levels would result in greater impacts to an individual 
animal.
    Injuries resulting from a shock wave take place at boundaries 
between tissues of different densities. Different velocities are 
imparted to tissues of different densities, and this can lead to their 
physical disruption. Blast effects are greatest at the gas-liquid 
interface (Landsberg, 2000). Gas-containing organs, particularly the 
lungs and gastrointestinal tract, are especially susceptible (Goertner, 
1982; Hill, 1978; Yelverton et al., 1973). Intestinal walls can bruise 
or rupture, with subsequent hemorrhage and escape of gut contents into 
the body cavity. Less severe gastrointestinal tract injuries include 
contusions, petechiae (small red or purple spots caused by bleeding in 
the skin), and slight hemorrhaging (Yelverton et al., 1973).
    Because the ears are the most sensitive to pressure, they are the 
organs most sensitive to injury (Ketten, 2000). Sound-related damage 
associated with sound energy from detonations can be theoretically 
distinct from injury from the shock wave, particularly farther from the 
explosion. If a noise is audible to an animal, it has the potential to 
damage the animal's hearing by causing decreased sensitivity (Ketten, 
1995). Lethal impacts are those that result in immediate death or 
serious debilitation in or near an intense source and are not, 
technically, pure acoustic trauma (Ketten, 1995). Sublethal impacts 
include hearing loss, which is caused by exposures to perceptible 
sounds. Severe damage (from the shock wave) to the ears includes 
tympanic membrane rupture, fracture of the ossicles, and damage to the 
cochlea, hemorrhage, and cerebrospinal fluid leakage into the middle 
ear. Moderate injury implies partial hearing loss due to tympanic 
membrane rupture and blood in the middle ear. Permanent hearing loss 
also can occur when the hair cells are damaged by one very loud event 
as well as by prolonged exposure to a loud noise or chronic exposure to 
noise. The level of impact from blasts depends on both an animal's 
location and, at outer zones, its sensitivity to the residual noise 
(Ketten, 1995).
    Given the mitigation measures proposed, it is unlikely that any of 
the more serious injuries or mortality discussed above are likely to 
result from any UXO/MEC detonation that Park City Wind might need to 
undertake. PTS, TTS, and brief startle reactions are the most likely 
impacts to result from this activity, if it occurs (noting detonation 
is the last method to be chosen for removal).

Potential Effects From Vessel Strike

    Vessel collisions with marine mammals, also referred to as vessel 
strikes or ship strikes, can result in death or serious injury of the 
animal. Wounds resulting from ship strike may include massive trauma, 
hemorrhaging, broken bones, or propeller lacerations (Knowlton and 
Kraus, 2001). An animal at the surface could be struck directly by a 
vessel, a surfacing animal could hit the bottom of a vessel, or an 
animal just below the surface could be cut by a vessel's propeller. 
Superficial strikes may not kill or result in the death of the animal. 
Lethal interactions are typically associated with large whales, which 
are occasionally found draped across the bulbous bow of large 
commercial ships upon arrival in port. Although smaller cetaceans are 
more maneuverable in relation to large vessels than are large whales, 
they may also be susceptible to strike. The severity of injuries 
typically depends on the size and speed of the vessel (Knowlton and 
Kraus, 2001; Laist et al., 2001; Vanderlaan and Taggart, 2007; Conn and 
Silber, 2013). Impact forces increase with speed, as does the 
probability of a strike at a given distance (Silber et al., 2010; Gende 
et al., 2011).
    The most vulnerable marine mammals are those that spend extended 
periods of time at the surface in order to restore oxygen levels within 
their tissues after deep dives (e.g., the sperm whale). In addition, 
some baleen whales seem generally unresponsive to vessel sound, making 
them more susceptible to vessel collisions (Nowacek et al., 2004). 
These species are primarily large, slow moving whales. Marine mammal 
responses to vessels may include avoidance and changes in dive pattern 
(NRC, 2003).
    An examination of all known ship strikes from all shipping sources 
(civilian and military) indicates vessel speed is a principal factor in 
whether a vessel strike occurs and, if so, whether it results in 
injury, serious injury, or mortality (Knowlton and Kraus, 2001; Laist 
et al., 2001; Jensen and Silber, 2003; Pace and Silber, 2005; 
Vanderlaan and Taggart, 2007; Conn and Silber, 2013). In assessing 
records in which vessel speed was known, Laist et al. (2001) found a 
direct relationship between the occurrence of a whale strike and the 
speed of the vessel involved in the collision. The authors concluded 
that most deaths occurred when a vessel was traveling in excess of 13 
knots.
    Jensen and Silber (2003) detailed 292 records of known or probable 
ship strikes of all large whale species from 1975 to 2002. Of these, 
vessel speed at the time of collision was reported for 58 cases. Of 
these 58 cases, 39 (or 67 percent) resulted in serious injury or death 
(19 of those resulted in serious injury as determined by blood in the 
water, propeller gashes or severed tailstock, and fractured skull, jaw, 
vertebrae, hemorrhaging, massive bruising or other injuries noted 
during necropsy and 20 resulted in death). Operating speeds of vessels 
that struck various species of large whales ranged from 2 to 51 knots. 
The majority (79 percent) of these strikes occurred at speeds of 13 
knots or greater. The average speed that resulted in serious injury or 
death was 18.6 knots. Pace and Silber (2005) found that the probability 
of death or serious injury increased rapidly with increasing vessel 
speed. Specifically, the predicted probability of serious injury or 
death increased from 45 to 75 percent as vessel speed increased from 10 
to 14 knots, and exceeded 90 percent at 17 knots. Higher speeds during 
collisions result in greater force of impact and also appear to 
increase the chance of severe injuries or death. While modeling studies 
have suggested that hydrodynamic forces pulling whales toward the 
vessel hull increase with increasing speed (Clyne, 1999; Knowlton et 
al., 1995), this is inconsistent with Silber et al. (2010), which 
demonstrated that there is no such relationship (i.e., hydrodynamic 
forces are independent of speed).
    In a separate study, Vanderlaan and Taggart (2007) analyzed the 
probability of lethal mortality of large whales at a given speed, 
showing that the greatest rate of change in the probability of a lethal 
injury to a large whale as a function of vessel speed occurs between 
8.6 and 15 knots. The chances of a lethal injury decline from 
approximately 80 percent at 15 knots to approximately 20 percent at 8.6 
knots. At speeds below 11.8 knots, the chances of lethal injury drop 
below 50 percent, while the probability asymptotically increases toward 
100 percent above 15 knots.
    The Jensen and Silber (2003) report notes that the Large Whale Ship 
Strike Database represents a minimum number of collisions, because the 
vast majority probably goes undetected or unreported. In contrast, the 
Project's personnel are likely to detect any strike that does occur 
because of the required personnel training and lookouts, along with the 
inclusion of Protected Species Observers (as described in the Proposed 
Mitigation section), and they are

[[Page 37639]]

required to report all ship strikes involving marine mammals.
    There are no known vessel strikes of marine mammals by any offshore 
wind energy vessel in the U.S. Given the extensive mitigation and 
monitoring measures (see the Proposed Mitigation and Proposed 
Monitoring and Reporting section) that would be required of Park City 
Wind, NMFS believes that a vessel strike is not likely to occur.

Potential Effects to Marine Mammal Habitat

    Park City Wind's proposed activities could potentially affect 
marine mammal habitat through the introduction of impacts to the prey 
species of marine mammals (through noise, oceanographic processes, or 
reef effects), acoustic habitat (sound in the water column), water 
quality, and biologically important habitat for marine mammals.
Effects on Prey
    Sound may affect marine mammals through impacts on the abundance, 
behavior, or distribution of prey species (e.g., crustaceans, 
cephalopods, fish, and zooplankton). Marine mammal prey varies by 
species, season, and location and, for some, is not well documented. 
Here, we describe studies regarding the effects of noise on known 
marine mammal prey.
    Fish utilize the soundscape and components of sound in their 
environment to perform important functions such as foraging, predator 
avoidance, mating, and spawning (e.g., Zelick and Mann, 1999; Fay, 
2009). The most likely effects on fishes exposed to loud, intermittent, 
low-frequency sounds are behavioral responses (i.e., flight or 
avoidance). Short duration, sharp sounds (such as pile driving or 
airguns) can cause overt or subtle changes in fish behavior and local 
distribution. The reaction of fish to acoustic sources depends on the 
physiological state of the fish, past exposures, motivation (e.g., 
feeding, spawning, migration), and other environmental factors. Key 
impacts to fishes may include behavioral responses, hearing damage, 
barotrauma (pressure-related injuries), and mortality. While it is 
clear that the behavioral responses of individual prey, such as 
displacement or other changes in distribution, can have direct impacts 
on the foraging success of marine mammals, the effects on marine 
mammals of individual prey that experience hearing damage, barotrauma, 
or mortality is less clear, though obviously population scale impacts 
that meaningfully reduce the amount of prey available could have more 
serious impacts.
    Fishes, like other vertebrates, have a variety of different sensory 
systems to glean information from ocean around them (Astrup and Mohl, 
1993; Astrup, 1999; Braun and Grande, 2008; Carroll et al., 2017; 
Hawkins and Johnstone, 1978; Ladich and Popper, 2004; Ladich and 
Schulz-Mirbach, 2016; Mann, 2016; Nedwell et al., 2004; Popper et al., 
2003; Popper et al., 2005). Depending on their hearing anatomy and 
peripheral sensory structures, which vary among species, fishes hear 
sounds using pressure and particle motion sensitivity capabilities and 
detect the motion of surrounding water (Fay et al., 2008) (terrestrial 
vertebrates generally only detect pressure). Most marine fishes 
primarily detect particle motion using the inner ear and lateral line 
system while some fishes possess additional morphological adaptations 
or specializations that can enhance their sensitivity to sound 
pressure, such as a gas-filled swim bladder (Braun and Grande, 2008; 
Popper and Fay, 2011).
    Hearing capabilities vary considerably between different fish 
species with data only available for just over 100 species out of the 
34,000 marine and freshwater fish species (Eschmeyer and Fong, 2016). 
In order to better understand acoustic impacts on fishes, fish hearing 
groups are defined by species that possess a similar continuum of 
anatomical features, which result in varying degrees of hearing 
sensitivity (Popper and Hastings, 2009a). There are four hearing groups 
defined for all fish species (modified from Popper et al., 2014) within 
this analysis, and they include: fishes without a swim bladder (e.g., 
flatfish, sharks, rays, etc.); fishes with a swim bladder not involved 
in hearing (e.g., salmon, cod, pollock, etc.); fishes with a swim 
bladder involved in hearing (e.g., sardines, anchovy, herring, etc.); 
and fishes with a swim bladder involved in hearing and high-frequency 
hearing (e.g., shad and menhaden). Most marine mammal fish prey species 
would not be likely to perceive or hear mid- or high-frequency sonars. 
While hearing studies have not been done on sardines and northern 
anchovies, it would not be unexpected for them to have hearing 
similarities to Pacific herring (up to 2-5 kHz) (Mann et al., 2005). 
Currently, less data are available to estimate the range of best 
sensitivity for fishes without a swim bladder.
    In terms of physiology, multiple scientific studies have documented 
a lack of mortality or physiological effects to fish from exposure to 
low- and mid-frequency sonar and other sounds (Halvorsen et al., 2012a; 
J[oslash]rgensen et al., 2005; Juanes et al., 2017; Kane et al., 2010; 
Kvadsheim and Sevaldsen, 2005; Popper et al., 2007; Popper et al., 
2016; Watwood et al., 2016). Techer et al. (2017) exposed carp in 
floating cages for up to 30 days to low-power 23 and 46 kHz source 
without any significant physiological response. Other studies have 
documented either a lack of TTS in species whose hearing range cannot 
perceive sonar (such as Navy sonar), or for those species that could 
perceive sonar-like signals, any TTS experienced would be recoverable 
(Halvorsen et al., 2012a; Ladich and Fay, 2013; Popper and Hastings, 
2009a, 2009b; Popper et al., 2014; Smith, 2016). Only fishes that have 
specializations that enable them to hear sounds above about 2,500 Hz 
(2.5 kHz), such as herring (Halvorsen et al., 2012a; Mann et al., 2005; 
Mann, 2016; Popper et al., 2014), would have the potential to receive 
TTS or exhibit behavioral responses from exposure to mid-frequency 
sonar. In addition, any sonar induced TTS to fish whose hearing range 
could perceive sonar would only occur in the narrow spectrum of the 
source (e.g., 3.5 kHz) compared to the fish's total hearing range 
(e.g., 0.01 kHz to 5 kHz).
    In terms of behavioral responses, Juanes et al. (2017) discuss the 
potential for negative impacts from anthropogenic noise on fish, but 
the author's focus was on broader based sounds, such as ship and boat 
noise sources. Watwood et al. (2016) also documented no behavioral 
responses by reef fish after exposure to mid-frequency active sonar. 
Doksaeter et al. (2009; 2012) reported no behavioral responses to mid-
frequency sonar (such as naval sonar) by Atlantic herring; 
specifically, no escape reactions (vertically or horizontally) were 
observed in free swimming herring exposed to mid-frequency sonar 
transmissions. Based on these results (Doksaeter et al., 2009; 
Doksaeter et al., 2012; Sivle et al., 2012), Sivle et al. (2014) 
created a model in order to report on the possible population-level 
effects on Atlantic herring from active sonar. The authors concluded 
that the use of sonar poses little risk to populations of herring 
regardless of season, even when the herring populations are aggregated 
and directly exposed to sonar. Finally, Bruintjes et al. (2016) 
commented that fish exposed to any short-term noise within their 
hearing range might initially startle, but would quickly return to 
normal behavior.
    Pile-driving noise during construction is of particular concern as 
the very high sound pressure levels could potentially prevent fish from 
reaching breeding or spawning sites, finding food, and acoustically 
locating mates. A playback

[[Page 37640]]

study in West Scotland revealed that there was a significant movement 
response to the pile-driving stimulus in both species at relatively low 
received sound pressure levels (sole: 144-156 dB re 1[mu]Pa Peak; cod: 
140-161 dB re 1 [mu]Pa Peak, particle motion between 6.51 x 10\3\ and 
8.62 x 10\4\ m/s\2\ peak) (Mueller-Blenkle et al., 2010). The swimming 
speed of sole increased significantly during the playback of 
construction noise when compared to the playbacks of before and after 
construction. While not statistically significant, cod also displayed a 
similar behavioral response during before, during, and after 
construction playbacks. However, cod demonstrated a specific and 
significant freezing response at the onset and cessation of the 
playback recording. In both species, indications were present 
displaying directional movements away from the playback source. During 
wind farm construction in the Eastern Taiwan Strait, Type 1 soniferous 
fish chorusing showed a relatively lower intensity and longer duration 
while Type 2 chorusing exhibited higher intensity and no changes in its 
duration. Deviation from regular fish vocalization patterns may affect 
fish reproductive success, cause migration, augmented predation, or 
physiological alterations.
    Occasional behavioral reactions to activities that produce 
underwater noise sources are unlikely to cause long-term consequences 
for individual fish or populations. The most likely impact to fish from 
impact and vibratory pile driving activities at the project areas would 
be temporary behavioral avoidance of the area. Any behavioral avoidance 
by fish of the disturbed area would still leave significantly large 
areas of fish and marine mammal foraging habitat in the nearby 
vicinity. The duration of fish avoidance of an area after pile driving 
stops is unknown, but a rapid return to normal recruitment, 
distribution and behavior is anticipated. In general, impacts to marine 
mammal prey species are expected to be minor and temporary due to the 
expected short daily duration of individual pile driving events and the 
relatively small areas being affected.
    SPLs of sufficient strength have been known to cause fish auditory 
impairment, injury and mortality. Popper et al. (2014) found that fish 
with or without air bladders could experience TTS at 186 dB 
SELcum. Mortality could occur for fish without swim bladders 
at >216 dB SELcum. Those with swim bladders or at the egg or 
larvae life stage, mortality was possible at >203 dB SELcum. 
Other studies found that 203 dB SELcum or above caused a 
physiological response in other fish species (Casper et al., 2012, 
Halvorsen et al., 2012a, Halvorsen et al., 2012b, Casper et al., 2013a; 
Casper et al., 2013b). However, in most fish species, hair cells in the 
ear continuously regenerate and loss of auditory function likely is 
restored when damaged cells are replaced with new cells. Halvorsen et 
al. (2012a) showed that a TTS of 4-6 dB was recoverable within 24 hours 
for one species. Impacts would be most severe when the individual fish 
is close to the source and when the duration of exposure is long. 
Injury caused by barotrauma can range from slight to severe and can 
cause death, and is most likely for fish with swim bladders. Barotrauma 
injuries have been documented during controlled exposure to impact pile 
driving (Halvorsen et al., 2012b; Casper et al., 2013).
    As described in the Proposed Mitigation section below, Park City 
Wind would utilize a sound attenuation device which would reduce 
potential for injury to marine mammal prey. Other fish that experience 
hearing loss as a result of exposure to impulsive sound sources may 
have a reduced ability to detect relevant sounds such as predators, 
prey, or social vocalizations. However, PTS has not been known to occur 
in fishes and any hearing loss in fish may be as temporary as the 
timeframe required to repair or replace the sensory cells that were 
damaged or destroyed (Popper et al., 2005; Popper et al., 2014; Smith 
et al., 2006). It is not known if damage to auditory nerve fibers could 
occur, and if so, whether fibers would recover during this process.
    It is also possible for fish to be injured or killed by an 
explosion from UXO/MEC detonation. Physical effects from pressure waves 
generated by underwater sounds (e.g., underwater explosions) could 
potentially affect fish within proximity of training or testing 
activities. The shock wave from an underwater explosion is lethal to 
fish at close range, causing massive organ and tissue damage and 
internal bleeding (Keevin and Hempen, 1997). At greater distance from 
the detonation point, the extent of mortality or injury depends on a 
number of factors including fish size, body shape, orientation, and 
species (Keevin and Hempen, 1997; Wright, 1982). At the same distance 
from the source, larger fish are generally less susceptible to death or 
injury, elongated forms that are round in cross-section are less at 
risk than deep-bodied forms, and fish oriented sideways to the blast 
suffer the greatest impact (Edds-Walton and Finneran, 2006; O'Keeffe, 
1984; O'Keeffe and Young, 1984; Wiley et al., 1981; Yelverton et al., 
1975). Species with gas-filled organs are more susceptible to injury 
and mortality than those without them (Gaspin, 1975; Gaspin et al., 
1976; Goertner et al., 1994). Barotrauma injuries have been documented 
during controlled exposure to impact pile driving (an impulsive noise 
source, as are explosives and airguns) (Halvorsen et al., 2012b; Casper 
et al., 2013a).
    Fish not killed by an explosion might change their behavior, 
feeding pattern, or distribution. Changes in behavior of fish have been 
observed as a result of sound produced by explosives, with effect 
intensified in areas of hard substrate (Wright, 1982). Stunning from 
pressure waves could also temporarily immobilize fish, making them more 
susceptible to predation. The abundances of various fish (and 
invertebrates) near the detonation point for explosives could be 
altered for a few hours before animals from surrounding areas 
repopulate the area. However, these populations would likely be 
replenished as waters near the detonation point are mixed with adjacent 
waters. Repeated exposure of individual fish to sounds from underwater 
explosions is not likely and are expected to be short-term and 
localized. Long-term consequences for fish populations would not be 
expected. Several studies have demonstrated that airgun sounds might 
affect the distribution and behavior of some fishes, potentially 
impacting foraging opportunities or increasing energetic costs (e.g., 
Fewtrell and McCauley, 2012; Pearson et al., 1992; Skalski et al., 
1992; Santulli et al., 1999; Paxton et al., 2017).
    UXO/MEC detonations would be dispersed in space and time; 
therefore, repeated exposure of individual fishes are unlikely. 
Mortality and injury effects to fishes from explosives would be 
localized around the area of a given in-water explosion but only if 
individual fish and the explosive (and immediate pressure field) were 
co-located at the same time. Fishes deeper in the water column or on 
the bottom would not be affected by water surface explosions. Repeated 
exposure of individual fish to sound and energy from underwater 
explosions is not likely given fish movement patterns, especially 
schooling prey species. Most acoustic effects, if any, are expected to 
be short-term and localized. Long-term consequences for fish 
populations, including key prey species within the project area, would 
not be expected.
    Required soft-starts would allow prey and marine mammals to move 
away from the source prior to any noise levels that may physically 
injure prey and the

[[Page 37641]]

use of the noise attenuation devices would reduce noise levels to the 
degree any mortality or injury of prey is also minimized. Use of bubble 
curtains, in addition to reducing impacts to marine mammals, for 
example, is a key mitigation measure in reducing injury and mortality 
of ESA-listed salmon on the U.S. West Coast. However, we recognize some 
mortality, physical injury and hearing impairment in marine mammal prey 
may occur, but we anticipate the amount of prey impacted in this manner 
is minimal compared to overall availability. Any behavioral responses 
to pile driving by marine mammal prey are expected to be brief. We 
expect that other impacts, such as stress or masking, would occur in 
fish that serve as marine mammals prey (Popper et al., 2019); however, 
those impacts would be limited to the duration of impact pile driving 
and during any UXO/MEC detonations and, if prey were to move out the 
area in response to noise, these impacts would be minimized.
    In addition to fish, prey sources such as marine invertebrates 
could potentially be impacted by noise stressors as a result of the 
proposed activities. However, most marine invertebrates' ability to 
sense sounds is limited. Invertebrates appear to be able to detect 
sounds (Pumphrey, 1950; Frings and Frings, 1967) and are most sensitive 
to low-frequency sounds (Packard et al., 1990; Budelmann and 
Williamson, 1994; Lovell et al., 2005; Mooney et al., 2010). Data on 
response of invertebrates such as squid, another marine mammal prey 
species, to anthropogenic sound is more limited (de Soto, 2016; Sole et 
al., 2017). Data suggest that cephalopods are capable of sensing the 
particle motion of sounds and detect low frequencies up to 1-1.5 kHz, 
depending on the species, and so are likely to detect airgun noise 
(Kaifu et al., 2008; Hu et al., 2009; Mooney et al., 2010; Samson et 
al., 2014). Sole et al. (2017) reported physiological injuries to 
cuttlefish in cages placed at-sea when exposed during a controlled 
exposure experiment to low-frequency sources (315 Hz, 139 to 142 dB re 
1 [mu]Pa\2\ and 400 Hz, 139 to 141 dB re 1 [mu]Pa\2\). Fewtrell and 
McCauley (2012) reported squids maintained in cages displayed startle 
responses and behavioral changes when exposed to seismic airgun sonar 
(136-162 re 1 [mu]Pa\2\[middot]s). Jones et al. (2020) found that when 
squid (Doryteuthis pealeii) were exposed to impulse pile driving noise, 
body pattern changes, inking, jetting, and startle responses were 
observed and nearly all squid exhibited at least one response. However, 
these responses occurred primarily during the first eight impulses and 
diminished quickly, indicating potential rapid, short-term habituation.
    Cephalopods have a specialized sensory organ inside the head called 
a statocyst that may help an animal determine its position in space 
(orientation) and maintain balance (Budelmann, 1992). Packard et al. 
(1990) showed that cephalopods were sensitive to particle motion, not 
sound pressure, and Mooney et al. (2010) demonstrated that squid 
statocysts act as an accelerometer through which particle motion of the 
sound field can be detected. Auditory injuries (lesions occurring on 
the statocyst sensory hair cells) have been reported upon controlled 
exposure to low-frequency sounds, suggesting that cephalopods are 
particularly sensitive to low-frequency sound (Andre et al., 2011; Sole 
et al., 2013). Behavioral responses, such as inking and jetting, have 
also been reported upon exposure to low-frequency sound (McCauley et 
al., 2000; Samson et al., 2014). Squids, like most fish species, are 
likely more sensitive to low frequency sounds and may not perceive mid- 
and high-frequency sonars. Cumulatively for squid as a prey species, 
individual and population impacts from exposure to explosives, like 
fish, are not likely to be significant, and explosive impacts would be 
short-term and localized.
    With regard to potential impacts on zooplankton, McCauley et al. 
(2017) found that exposure to airgun noise resulted in significant 
depletion for more than half the taxa present and that there were two 
to three times more dead zooplankton after airgun exposure compared 
with controls for all taxa, within 1 km of the airguns. However, the 
authors also stated that in order to have significant impacts on r-
selected species (i.e., those with high growth rates and that produce 
many offspring) such as plankton, the spatial or temporal scale of 
impact must be large in comparison with the ecosystem concerned, and it 
is possible that the findings reflect avoidance by zooplankton rather 
than mortality (McCauley et al., 2017). In addition, the results of 
this study are inconsistent with a large body of research that 
generally finds limited spatial and temporal impacts to zooplankton as 
a result of exposure to airgun noise (e.g., Dalen and Knutsen, 1987; 
Payne, 2004; Stanley et al., 2011). Most prior research on this topic, 
which has focused on relatively small spatial scales, has showed 
minimal effects (e.g., Kostyuchenko, 1973; Booman et al., 1996; 
S[aelig]tre and Ona, 1996; Pearson et al., 1994; Bolle et al., 2012).
    A modeling exercise was conducted as a follow-up to the McCauley et 
al. (2017) study (as recommended by McCauley et al.), in order to 
assess the potential for impacts on ocean ecosystem dynamics and 
zooplankton population dynamics (Richardson et al., 2017). Richardson 
et al. (2017) found that a full-scale airgun survey would impact 
copepod abundance within the survey area, but that effects at a 
regional scale were minimal (2 percent decline in abundance within 150 
km of the survey area and effects not discernible over the full 
region). The authors also found that recovery within the survey area 
would be relatively quick (3 days following survey completion), and 
suggest that the quick recovery was due to the fast growth rates of 
zooplankton, and the dispersal and mixing of zooplankton from both 
inside and outside of the impacted region. The authors also suggest 
that surveys in areas with more dynamic ocean circulation in comparison 
with the study region and/or with deeper waters (i.e., typical offshore 
wind locations) would have less net impact on zooplankton.
    Notably, a recently described study produced results inconsistent 
with those of McCauley et al. (2017). Researchers conducted a field and 
laboratory study to assess if exposure to airgun noise affects 
mortality, predator escape response, or gene expression of the copepod 
Calanus finmarchicus (Fields et al., 2019). Immediate mortality of 
copepods was significantly higher, relative to controls, at distances 
of 5 m or less from the airguns. Mortality 1 week after the airgun 
blast was significantly higher in the copepods placed 10 m from the 
airgun but was not significantly different from the controls at a 
distance of 20 m from the airgun. The increase in mortality, relative 
to controls, did not exceed 30 percent at any distance from the airgun. 
Moreover, the authors caution that even this higher mortality in the 
immediate vicinity of the airguns may be more pronounced than what 
would be observed in free-swimming animals due to increased flow speed 
of fluid inside bags containing the experimental animals. There were no 
sub-lethal effects on the escape performance or the sensory threshold 
needed to initiate an escape response at any of the distances from the 
airgun that were tested. Whereas McCauley et al. (2017) reported an SEL 
of 156 dB at a range of 509-658 m, with zooplankton mortality observed 
at that range, Fields et al. (2019) reported an

[[Page 37642]]

SEL of 186 dB at a range of 25 m, with no reported mortality at that 
distance.
    The presence of large numbers of turbines has been shown to impact 
meso- and sub-meso-scale water column circulation, which can affect the 
density, distribution, and energy content of zooplankton and thereby, 
their availability as marine mammal prey. Topside, atmospheric wakes 
result in wind speed reductions influencing upwelling and downwelling 
in the ocean while underwater structures such as WTG and ESP 
foundations may cause turbulent current wakes, which impact 
circulation, stratification, mixing, and sediment resuspension (Daewel 
et al., 2022). Overall, the presence and operation of structures such 
as wind turbines are, in general, likely to result in local and broader 
oceanographic effects in the marine environment and may disrupt marine 
mammal prey, such as dense aggregations and distribution of zooplankton 
through altering the strength of tidal currents and associated fronts, 
changes in stratification, primary production, the degree of mixing, 
and stratification in the water column (Chen et al., 2021; Johnson et 
al., 2021; Christiansen et al., 2022; Dorrell et al., 2022). However, 
the scale of impacts is difficult to predict and may vary from meters 
to hundreds of meters for local individual turbine impacts (Schultze et 
al., 2020) to large-scale dipoles of surface elevation changes 
stretching hundreds of kilometers (Christiansen et al., 2022).
    Park City Wind intends to install up to 130 WTG and ESP positions. 
Two positions may potentially have co-located ESPs (i.e., 1 WTG and 1 
ESP foundation installed at 1 grid position), resulting in 132 
foundations with turbine operations commencing in 2027 and all turbines 
being operational in 2028. As described above, there is scientific 
uncertainty around the scale of oceanographic impacts (meters to 
kilometers) associated with turbine operation. The project is located 
in an area of southern New England that experiences coastal upwelling, 
a consequence of the predominant wind direction and the orientation of 
the coastline. Along the coast of Rhode Island and southern 
Massachusetts, upwelling of deeper, nutrient-rich waters frequently 
leads to late summer blooms of phytoplankton and subsequently increased 
biological productivity (Gong et al., 2010; Glenn et al., 2004). The 
lease area is located within a core winter foraging habitat for North 
Atlantic right whales (Leiter et al., 2017; Quintano-Rizzo et al., 
2021); however, prime foraging habitat on and near Nantucket Shoals is 
unlikely to be influenced.
    These potential impacts on prey could impact the distribution of 
marine mammals within the project area, potentially necessitating 
additional energy expenditure to find and capture prey, but at the 
temporal and spatial scales anticipated for this activity are not 
expected to impact the reproduction or survival of any individual 
marine mammals. Although studies assessing the impacts of offshore wind 
development on marine mammals are limited, the repopulation of wind 
energy areas by harbor porpoises (Brandt et al., 2016; Lindeboom et 
al., 2011) and harbor seals (Lindeboom et al., 2011; Russell et al., 
2016) following the installation of wind turbines are promising. 
Overall, any impacts to marine mammal foraging capabilities due to 
effects on prey aggregation from the turbine presence and operation 
during the effective period of the proposed rule is likely to be 
limited. Nearby habitat that is known to support North Atlantic right 
whale foraging would be unaffected by the project's operation.
    In general, impacts to marine mammal prey species are expected to 
be relatively minor and temporary due to the expected short daily 
duration of individual pile driving events and the relatively small 
areas being affected. The most likely impacts of prey fish from UXO/MEC 
detonations, if determined to be necessary, are injury or mortality if 
they are located within the vicinity when detonation occurs. However, 
given the likely spread of any UXOs/MECs in the project area, the low 
chance of detonation (as lift-and-shift and deflagration are the 
primary removal approaches), and that this area is not a biologically 
important foraging ground, overall effects should be minimal to marine 
mammal species. NMFS does not expect HRG acoustic sources to impact 
fish and most sources are likely outside the hearing range of the 
primary prey species in the project area.
    Overall, the combined impacts of sound exposure, explosions, water 
quality, and oceanographic impacts on marine mammal habitat resulting 
from the proposed activities would not be expected to have measurable 
effects on populations of marine mammal prey species. Prey species 
exposed to sound might move away from the sound source, experience TTS, 
experience masking of biologically relevant sounds, or show no obvious 
direct effects.
Reef Effects
    The presence of monopile foundations, scour protection, and cable 
protection will result in a conversion of the existing sandy bottom 
habitat to a hard bottom habitat with areas of vertical structural 
relief. This could potentially alter the existing habitat by creating 
an ``artificial reef effect'' that results in colonization by 
assemblages of both sessile and mobile animals within the new hard-
bottom habitat (Wilhelmsson et al., 2006; Reubens et al., 2013; 
Bergstr[ouml]m et al., 2014; Coates et al., 2014). This colonization by 
marine species, especially hard-substrate preferring species, can 
result in changes to the diversity, composition, and/or biomass of the 
area thereby impacting the trophic composition of the site (Wilhelmsson 
et al., 2010, Krone et al., 2013; Bergstr[ouml]m et al., 2014, Hooper 
et al., 2017; Raoux et al., 2017; Harrison and Rousseau, 2020; Taormina 
et al., 2020; Buyse et al., 2022a; ter Hofstede et al., 2022).
    Artificial structures can create increased habitat heterogeneity 
important for species diversity and density (Langhamer, 2012). The WTG 
and ESP foundations will extend through the water column, which may 
serve to increase settlement of meroplankton or planktonic larvae on 
the structures in both the pelagic and benthic zones (Boehlert and 
Gill, 2010). Fish and invertebrate species are also likely to aggregate 
around the foundations and scour protection which could provide 
increased prey availability and structural habitat (Boehlert and Gill, 
2010; Bonar et al., 2015). Further, instances of species previously 
unknown, rare, or nonindigenous to an area have been documented at 
artificial structures, changing the composition of the food web and 
possibly the attractability of the area to new or existing predators 
(Adams et al., 2014; de Mesel, 2015; Bishop et al., 2017; Hooper et 
al., 2017; Raoux et al., 2017; van Hal et al., 2017; Degraer et al., 
2020; Fernandez-Betelu et al., 2022). Notably, there are examples of 
these sites becoming dominated by marine mammal prey species, such as 
filter-feeding species and suspension-feeding crustaceans (Andersson 
and [Ouml]hman, 2010; Slavik et al., 2019; Hutchison et al., 2020; Pezy 
et al., 2020; Mavraki et al., 2022).
    Numerous studies have documented significantly higher fish 
concentrations including species like cod and pouting (Trisopterus 
luscus), flounder (Platichthys flesus), eelpout (Zoarces viviparus), 
and eel (Anguilla anguilla) near in-water structures than in

[[Page 37643]]

surrounding soft bottom habitat (Langhamer and Wilhelmsson, 2009; 
Bergstr[ouml]m et al., 2013; Reubens et al., 2013). In the German Bight 
portion of the North Sea, fish were most densely congregated near the 
anchorages of jacket foundations, and the structures extending through 
the water column were thought to make it more likely that juvenile or 
larval fish encounter and settle on them (Rhode Island Coastal 
Resources Management Council (RI-CRMC), 2010; Krone et al., 2013). In 
addition, fish can take advantage of the shelter provided by these 
structures while also being exposed to stronger currents created by the 
structures, which generate increased feeding opportunities and 
decreased potential for predation (Wilhelmsson et al., 2006). The 
presence of the foundations and resulting fish aggregations around the 
foundations is expected to be a long-term habitat impact, but the 
increase in prey availability could potentially be beneficial for some 
marine mammals.
    The most likely impact to marine mammal habitat from the project is 
expected to be from pile driving and UXO/MEC detonations, which may 
affect marine mammal food sources such as forage fish and could also 
affect acoustic habitat effects on marine mammal prey (e.g., fish).
Water Quality
    Temporary and localized reduction in water quality will occur as a 
result of in-water construction activities. Most of this effect will 
occur during pile driving and installation of the cables, including 
auxiliary work such as dredging and scour placement. These activities 
will disturb bottom sediments and may cause a temporary increase in 
suspended sediment in the project area. Currents should quickly 
dissipate any raised total suspended sediment (TSS) levels, and levels 
should return to background levels once the project activities in that 
area cease. No direct impacts on marine mammals is anticipated due to 
increased TSS and turbidity; however, turbidity within the water column 
has the potential to reduce the level of oxygen in the water and 
irritate the gills of prey fish species in the proposed project area. 
However, turbidity plumes associated with the project would be 
temporary and localized, and fish in the proposed project area would be 
able to move away from and avoid the areas where plumes may occur. 
Therefore, it is expected that the impacts on prey fish species from 
turbidity, and therefore on marine mammals, would be minimal and 
temporary.
    Equipment used by Park City Wind within the project area, including 
ships and other marine vessels, potentially aircrafts, and other 
equipment, are also potential sources of by-products (e.g., 
hydrocarbons, particulate matter, heavy metals). All equipment is 
properly maintained in accordance with applicable legal requirements. 
All such operating equipment meets Federal water quality standards, 
where applicable. Given these requirements, impacts to water quality 
are expected to be minimal.
Acoustic Habitat
    Acoustic habitat is the soundscape, which encompasses all of the 
sound present in a particular location and time, as a whole when 
considered from the perspective of the animals experiencing it. Animals 
produce sound for, or listen for sounds produced by, conspecifics 
(communication during feeding, mating, and other social activities), 
other animals (finding prey or avoiding predators), and the physical 
environment (finding suitable habitats, navigating). Together, sounds 
made by animals and the geophysical environment (e.g., produced by 
earthquakes, lightning, wind, rain, waves) make up the natural 
contributions to the total acoustics of a place. These acoustic 
conditions, termed acoustic habitat, are one attribute of an animal's 
total habitat.
    Soundscapes are also defined by, and acoustic habitat influenced 
by, the total contribution of anthropogenic sound. This may include 
incidental emissions from sources such as vessel traffic or may be 
intentionally introduced to the marine environment for data acquisition 
purposes (as in the use of airgun arrays) or for Navy training and 
testing purposes (as in the use of sonar and explosives and other 
acoustic sources). Anthropogenic noise varies widely in its frequency, 
content, duration, and loudness and these characteristics greatly 
influence the potential habitat-mediated effects to marine mammals 
(please also see the previous discussion on Masking), which may range 
from local effects for brief periods of time to chronic effects over 
large areas and for long durations. Depending on the extent of effects 
to habitat, animals may alter their communications signals (thereby 
potentially expending additional energy) or miss acoustic cues (either 
conspecific or adventitious). Problems arising from a failure to detect 
cues are more likely to occur when noise stimuli are chronic and 
overlap with biologically relevant cues used for communication, 
orientation, and predator/prey detection (Francis and Barber, 2013). 
For more detail on these concepts, see Barber et al., 2009; Pijanowski 
et al., 2011; Francis and Barber, 2013; Lillis et al., 2014.
    The term ``listening area'' refers to the region of ocean over 
which sources of sound can be detected by an animal at the center of 
the space. Loss of communication space concerns the area over which a 
specific animal signal, used to communicate with conspecifics in 
biologically important contexts (e.g., foraging, mating), can be heard, 
in noisier relative to quieter conditions (Clark et al., 2009). Lost 
listening area concerns the more generalized contraction of the range 
over which animals would be able to detect a variety of signals of 
biological importance, including eavesdropping on predators and prey 
(Barber et al., 2009). Such metrics do not, in and of themselves, 
document fitness consequences for the marine animals that live in 
chronically noisy environments. Long-term population-level consequences 
mediated through changes in the ultimate survival and reproductive 
success of individuals are difficult to study, and particularly so 
underwater. However, it is increasingly well documented that aquatic 
species rely on qualities of natural acoustic habitats, with 
researchers quantifying reduced detection of important ecological cues 
(e.g., Francis and Barber, 2013; Slabbekoorn et al., 2010) as well as 
survivorship consequences in several species (e.g., Simpson et al., 
2014; Nedelec et al., 2014).
    Sound produced from construction activities in the project area 
would be temporary and transitory. The sounds produced during 
construction activities may be widely dispersed or concentrated in 
small areas for varying periods. Any anthropogenic noise attributed to 
construction activities in the project area would be temporary and the 
affected area would be expected to immediately return to the original 
state when these activities cease.
    Although this proposed rulemaking primarily covers the noise 
produced from construction activities relevant to this offshore wind 
facility, operational noise was a consideration in NMFS' analysis of 
the project, as all turbines would become operational within the 
effective dates of the rule (if issued). It is expected that all 
turbines would be operational in 2028. Once operational, offshore wind 
turbines are known to produce continuous, non-impulsive underwater 
noise, primarily below 1 kHz (Tougaard et al., 2020; St[ouml]ber and 
Thomsen, 2021).
    In both newer, quieter, direct-drive systems (such as what has been

[[Page 37644]]

proposed for use in the Project) and older generation, geared turbine 
designs, recent scientific studies indicate that operational noise from 
turbines is on the order of 110 to 125 dB re 1 [mu]Pa root-mean-square 
sound pressure level (SPLrms) at an approximate distance of 
50 m (Tougaard et al., 2020). Recent measurements of operational sound 
generated from wind turbines (direct drive, 6 MW, jacket piles) at 
Block Island wind farm (BIWF) indicate average broadband levels of 119 
dB at 50 m from the turbine, with levels varying with wind speed (HDR, 
Inc., 2019). Interestingly, measurements from BIWF turbines showed 
operational sound had less tonal components compared to European 
measurements of turbines with gear boxes.
    Tougaard et al. (2020) further stated that the operational noise 
produced by WTGs is static in nature and lower than noise produced by 
passing ships. This is a noise source in this region to which marine 
mammals are likely already habituated. Furthermore, operational noise 
levels are likely lower than those ambient levels already present in 
active shipping lanes, such that operational noise would likely only be 
detected in very close proximity to the WTG (Thomsen et al., 2006; 
Tougaard et al., 2020). Similarly, recent measurements from a wind farm 
(3 MW turbines) in China found at above 300 Hz, turbines produced sound 
that was similar to background levels (Zhang et al., 2021). Other 
studies by Jansen and de Jong (2016) and Tougaard et al. (2009) 
determined that, while marine mammals would be able to detect 
operational noise from offshore wind farms (again, based on older 2 MW 
models) for several kilometers, they expected no significant impacts on 
individual survival, population viability, marine mammal distribution, 
or the behavior of the animals considered in their study (harbor 
porpoises and harbor seals).
    More recently, St[ouml]ber and Thomsen (2021) used monitoring data 
and modeling to estimate noise generated by more recently developed, 
larger (10 MW) direct-drive WTGs. Their findings, similar to Tougaard 
et al. (2020), demonstrate that there is a trend that operational noise 
increases with turbine size. Their study predicts broadband source 
levels could exceed 170 dB SPLrms for a 10 MW WTG; however, 
those noise levels were generated based on geared turbines; newer 
turbines operate with direct drive technology. The shift from using 
gear boxes to direct drive technology is expected to reduce the levels 
by 10 dB. The findings in the St[ouml]ber and Thomsen (2021) study have 
not been experimentally validated, though the modeling (using largely 
geared turbines) performed by Tougaard et al. (2020) yields similar 
results for a hypothetical 10 MW WTG. Overall, noise from operating 
turbines would raise ambient noise levels in the immediate vicinity of 
the turbines; however, the spatial extent of increased noise levels 
would be limited. NMFS proposes to require Park City Wind to measure 
operational noise levels.
    In addition, Madsen et al. (2006b) found the intensity of noise 
generated by operational wind turbines to be much less than the noises 
present during construction, although this observation was based on a 
single turbine with a maximum power of 2 MW. Other studies by Jansen 
and de Jong (2016) and Tougaard et al. (2009) determined that, while 
marine mammals would be able to detect operational noise from offshore 
wind farms (again, based on older 2 MW models) for several thousand 
kilometer, they expected no significant impacts on individual survival, 
population viability, marine mammal distribution, or the behavior of 
the animals considered in their study (harbor porpoises and harbor 
seals).
    More recently, St[ouml]ber and Thomsen (2021) used monitoring data 
and modeling to estimate noise generated by more recently developed, 
larger (10 MW) direct-drive WTGs. Their findings, similar to Tougaard 
et al. (2020), demonstrate that there is a trend that operational noise 
increases with turbine size. Their study found noise levels could 
exceed 170 (to 177 dB re 1 [mu]Pa SPLrms for a 10 MW WTG); 
however, those noise levels were generated by geared turbines, but 
newer turbines operate with direct drive technology. The shift from 
using gear boxes to direct drive technology is expected to reduce the 
sound level by 10 dB. The findings in the St[ouml]ber and Thomsen 
(2021) study have not been validated. Park City Wind did not request, 
and NMFS is not proposing to authorize, take incidental to operational 
noise from WTGs. Therefore, the topic is not discussed or analyzed 
further herein.

Estimated Take of Marine Mammals

    This section provides an estimate of the number of incidental takes 
proposed for authorization through the regulations, which will inform 
both NMFS' consideration of ``small numbers'' and the negligible impact 
determination.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance, which has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment) 
or has the potential to disturb a marine mammal or marine mammal stock 
in the wild by causing disruption of behavioral patterns, including, 
but not limited to, migration, breathing, nursing, breeding, feeding, 
or sheltering (Level B harassment).
    Authorized takes would primarily be by Level B harassment, as noise 
from pile driving, drilling, HRG surveys, and UXO/MEC detonations could 
result in behavioral disturbance of marine mammals that qualifies as 
take. Impacts such as masking and TTS can contribute to the disruption 
of behavioral patterns and are accounted for within those takes 
proposed for authorization. There is also some potential for auditory 
injury (Level A harassment) of all marine mammals except North Atlantic 
right whales. However, the amount of Level A harassment that Park City 
Wind requested, and NMFS proposes to authorize, is low. While NMFS is 
proposing to authorize Level A harassment and Level B harassment, the 
proposed mitigation and monitoring measures are expected to minimize 
the amount and severity of such taking to the extent practicable (see 
Proposed Mitigation and Proposed Monitoring and Reporting).
    As described previously, no serious injury or mortality is 
anticipated or proposed to be authorized incidental to the specified 
activities. Even without mitigation, both pile driving activities and 
HRG surveys would not have the potential to directly cause marine 
mammal mortality or serious injury. However, NMFS is proposing measures 
to more comprehensively reduce impacts to marine mammal species. While, 
in general, mortality and serious injury of marine mammals could occur 
from vessel strikes or UXO/MEC detonation if an animal is close enough 
to the source, the mitigation and monitoring measures contained within 
this proposed rule would avoid vessel strikes and the potential for 
marine mammals to be close enough to any UXO/MEC detonation to incur 
mortality or non-auditory injury (see Proposed Mitigation section). No 
other activities have the potential to result in mortality or serious 
injury.
    For acoustic impacts, we estimate take by considering: (1) acoustic 
thresholds above which the best available science indicates marine 
mammals will be behaviorally harassed or incur some degree of permanent 
hearing impairment; (2) the area or volume of

[[Page 37645]]

water that will be ensonified above these levels in a day; (3) the 
density or occurrence of marine mammals within these ensonified areas; 
and, (4) the number of days of activities. We note that while these 
factors can contribute to a basic calculation to provide an initial 
prediction of potential takes, additional information that can 
qualitatively inform take estimates is also sometimes available (e.g., 
previous monitoring results or average group size). Below, we describe 
the factors considered here in more detail and present the proposed 
take estimates.
    As described below, there are multiple methods available to predict 
density or occurrence and, for each species and activity, the largest 
value resulting from the three take estimation methods described below 
(i.e., density-based, PSO-based, or mean group size) was carried 
forward as the amount of take proposed for authorization, by Level B 
harassment. The amount of take proposed for authorization, by Level A 
harassment, reflects the density-based exposure estimates and, for some 
species and activities, consideration of other data such as mean group 
size.
    Below, we describe NMFS' acoustic thresholds, acoustic and exposure 
modeling methodologies, marine mammal density calculation methodology, 
occurrence information, and the modeling and methodologies applied to 
estimate take for each of the Project's proposed construction 
activities. NMFS has carefully considered all information and analysis 
presented by Park City Wind, as well as all other applicable 
information and, based on the best available science, concurs that the 
Project's estimates of the types and amounts of take for each species 
and stock are reasonable, and is proposing to authorize the amount 
requested. NMFS notes the take estimates described herein for 
foundation installation can be considered conservative as the estimates 
do not reflect the implementation of clearance and shutdown zones for 
any marine mammal species or stock.

Acoustic Thresholds

    NMFS recommends the use of acoustic thresholds that identify the 
received level of underwater sound above which exposed marine mammals 
would be reasonably expected to be behaviorally harassed (Level B 
harassment) or to incur PTS of some degree (Level A harassment). A 
summary of all NMFS' thresholds can be found at https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
Level B Harassment
    Though significantly driven by received level, the onset of 
behavioral disturbance from anthropogenic noise exposure is also 
informed to varying degrees by other factors related to the source or 
exposure context (e.g., frequency, predictability, duty cycle, duration 
of the exposure, signal-to-noise ratio, distance to the source, ambient 
noise, and the receiving animal's hearing, motivation, experience, 
demography, behavior at time of exposure, life stage, depth) and can be 
difficult to predict (e.g., Southall et al., 2007, 2021; Ellison et 
al., 2012). Based on what the available science indicates and the 
practical need to use a threshold based on a metric that is both 
predictable and measurable for most activities, NMFS typically uses a 
generalized acoustic threshold based on received level to estimate the 
onset of behavioral harassment.
    NMFS generally predicts that marine mammals are likely to be 
behaviorally harassed in a manner considered to be Level B harassment 
when exposed to underwater anthropogenic noise above the received sound 
pressure levels (SPLRMS) of 120 dB for continuous sources 
(e.g., vibratory pile-driving, drilling) and above the received 
SPLRMS 160 dB for non-explosive impulsive or intermittent 
sources (e.g., impact pile driving, scientific sonar). Generally 
speaking, Level B harassment take estimates based on these behavioral 
harassment thresholds are expected to include any likely takes by TTS 
as, in most cases, the likelihood of TTS occurs at distances from the 
source less than those at which behavioral harassment is likely. TTS of 
a sufficient degree can manifest as behavioral harassment, as reduced 
hearing sensitivity and the potential reduced opportunities to detect 
important signals (conspecific communication, predators, prey) may 
result in changes in behavioral patterns that would not otherwise 
occur.
    The proposed Project's construction activities include the use of 
continuous (e.g., vibratory pile driving, drilling) and impulsive or 
intermittent sources (e.g., impact pile driving, some HRG acoustic 
sources); therefore, the 120 and 160 dB re 1 [mu]Pa (rms) thresholds 
are applicable to our analysis. Level B harassment thresholds 
associated with UXO/MEC detonations are addressed in the Explosives 
Source Thresholds section below.
Level A Harassment
    NMFS' Technical Guidance for Assessing the Effects of Anthropogenic 
Sound on Marine Mammal Hearing (Version 2.0; Technical Guidance) (NMFS, 
2018) identifies dual criteria to assess auditory injury (Level A 
harassment) to five different marine mammal groups (based on hearing 
sensitivity) as a result of exposure to noise from two different types 
of sources (impulsive or non-impulsive). As dual metrics, NMFS 
considers onset of PTS (Level A harassment) to have occurred when 
either one of the two metrics is exceeded (i.e., metric resulting in 
the largest isopleth). As described above, Park City Wind's proposed 
activities include the use of both impulsive and non-impulsive sources. 
NMFS' thresholds identifying the onset of PTS are provided in Table 7. 
The references, analysis, and methodology used in the development of 
the thresholds are described in NMFS' 2018 Technical Guidance, which 
may be accessed at www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

[[Page 37646]]



                           Table 7--Permanent Threshold Shift (PTS) Onset Thresholds *
                                                  [NMFS, 2018]
----------------------------------------------------------------------------------------------------------------
                                                         PTS onset thresholds * (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-Impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: Lp,0-pk,flat: 219   Cell 2: LE,p, LF,24h: 199 dB.
                                          dB; LE,p, LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3: Lp,0-pk,flat: 230   Cell 4: LE,p, MF,24h: 198 dB.
                                          dB; LE,p, MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: Lp,0-pk,flat: 202   Cell 4: LE,p, HF,24h: 198 dB.
                                          dB; LE,p,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: Lp,0-pk,flat: 218   Cell 8: LE,p,PW,24h: 201 dB.
                                          dB; LE,p,PW,24h: 185 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric thresholds for impulsive sounds: Use whichever results in the largest isopleth for calculating PTS
  onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level thresholds
  associated with impulsive sounds, these thresholds are recommended for consideration.
Note: Peak sound pressure level (L0-pk) has a reference value of 1 [micro]Pa, and weighted cumulative sound
  exposure level (LE,) has a reference value of 1[micro]Pa\2\s. In this table, thresholds are abbreviated to be
  more reflective of International Organization for Standardization standards (ISO, 2017). The subscript
  ``flat'' is being included to indicate peak sound pressure are flat weighted or unweighted within the
  generalized hearing range of marine mammals (i.e., 7 Hz to 160 kHz). The subscript associated with cumulative
  sound exposure level thresholds indicates the designated marine mammal auditory weighting function (LF, MF,
  and HF cetaceans, and PW pinnipeds) and that the recommended accumulation period is 24 hours. The weighted
  cumulative sound exposure level thresholds could be exceeded in a multitude of ways (i.e., varying exposure
  levels and durations, duty cycle). When possible, it is valuable for action proponents to indicate the
  conditions under which these thresholds will be exceeded.

Explosives Source Thresholds
    Based on the best scientific information available, NMFS uses the 
acoustic and pressure thresholds indicated in Table 8 to predict the 
onset of PTS and TTS during UXO/MEC detonation. For a single detonation 
(within a 24-hour period), NMFS relies on the TTS onset threshold to 
assess the potential for Level B harassment. The proposed rule is 
conditioned such that Park City Wind would limit detonations to one per 
day and would be limited to daylight hours only.

        Table 8--PTS Onset, TTS Onset, for Underwater Explosives
                              [NMFS, 2018]
------------------------------------------------------------------------
                                     PTS impulsive       TTS impulsive
          Hearing group               thresholds          thresholds
------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans....  Cell 1: Lpk,flat:   Cell 2: Lpk,flat:
                                   219 dB;             213 dB LE,LF,24h:
                                   LE,LF,24h: 183 dB.  168 dB.
Mid-Frequency (MF) Cetaceans....  Cell 4: Lpk,flat:   Cell 5: Lpk,flat:
                                   230 dB;             224 dB;
                                   LE,MF,24h: 185 dB.  LE,MF,24h: 170
                                                       dB.
High-Frequency (HF) Cetaceans...  Cell 7: Lpk,flat:   Cell 8: Lpk,flat:
                                   202 dB;             196 dB;
                                   LE,HF,24h: 155 dB.  LE,HF,24h: 140
                                                       dB.
Phocid Pinnipeds (PW)             Cell 10: Lpk,flat:  Cell 11: Lpk,flat:
 (Underwater).                     218 dB;             212 dB;
                                   LE,PW,24h: 185 dB.  LE,PW,24h: 170
                                                       dB.
------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever
  results in the largest isopleth for calculating PTS/TTS onset.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa,
  and cumulative sound exposure level (LE) has a reference value of
  1[micro]Pa\2\s. In this table, thresholds are abbreviated to reflect
  American National Standards Institute standards (ANSI, 2013). However,
  ANSI defines peak sound pressure as incorporating frequency weighting,
  which is not the intent for this Technical Guidance. Hence, the
  subscript ``flat'' is being included to indicate peak sound pressure
  should be flat weighted or unweighted within the overall marine mammal
  generalized hearing range. The subscript associated with cumulative
  sound exposure level thresholds indicates the designated marine mammal
  auditory weighting function (LF, MF, and HF cetaceans, and PW
  pinnipeds) and that the recommended accumulation period is 24 hours.
  The cumulative sound exposure level thresholds could be exceeded in a
  multitude of ways (i.e., varying exposure levels and durations, duty
  cycle). When possible, it is valuable for action proponents to
  indicate the conditions under which these acoustic thresholds will be
  exceeded.

    Additional thresholds for non-auditory injury to lung and 
gastrointestinal (GI) tracts from the blast shock wave and/or onset of 
high peak pressures are also relevant (at relatively close ranges) as 
UXO/MEC detonations, in general, have potential to result in mortality 
and non-auditory injury (Table 9). Marine mammal lung injury criteria 
have been developed by the U.S. Navy (DoN (U.S. Department of the 
Navy), 2017) and are based on the mass of the animal and the depth at 
which it is present in the water column due to blast pressure. This 
means that specific decibel levels for each hearing group are not 
provided and instead, the criteria are presented as equations that 
allow for incorporation of specific mass and depth values. The GI tract 
injury threshold is based on peak pressure. The modified Goertner 
equations below represent the potential onset of lung injury and GI 
tract injury (Table 9).

                                 Table 9--Lung and G.I. Tract Injury Thresholds
                                                   [DoN, 2017]
----------------------------------------------------------------------------------------------------------------
                                     Mortality (severe    Slight lung injury
          Hearing group               lung injury) *              *                    G.I. tract injury
----------------------------------------------------------------------------------------------------------------
All Marine Mammals...............  Cell 1: Modified      Cell 2: Modified     Cell 3: Lpk,flat: 237 dB.
                                    Goertner model;       Goertner model;
                                    Equation 1.           Equation 2.
----------------------------------------------------------------------------------------------------------------
* Lung injury (severe and slight) thresholds are dependent on animal mass (Recommendation: Table C.9 from DoN
  (2017) based on adult and/or calf/pup mass by species).
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa. In this table, thresholds are abbreviated
  to reflect American National Standards Institute standards (ANSI, 2013). However, ANSI defines peak sound
  pressure as incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the
  subscript ``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted
  within the overall marine mammal generalized hearing range.

[[Page 37647]]

 
Modified Goertner Equations for severe and slight lung injury (pascal-second):
Equation 1: 103M1/3(1 + D/10.1)1/6 Pa-s.
Equation 2: 47.5M1/3(1 + D/10.1)1/6 Pa-s.
M animal (adult and/or calf/pup) mass (kg) (Table C.9 in DoN, 2017).
D animal depth (meters).

    Below, we describe the assumptions and methodologies used to 
estimate take, in consideration of acoustic thresholds and appropriate 
marine mammals density and occurrence information, for WTG and ESP 
foundation installation, UXO/MEC detonation, and HRG surveys. Resulting 
distances to thresholds, densities used, activity-specific exposure 
estimates (as relevant to the analysis), and activity-specific take 
estimates can be found in each activity subsection below. At the end of 
this section, we present the amount of annual and 5-year take that Park 
City Wind requested, and NMFS proposes to authorize, from all 
activities combined.

Acoustic and Exposure Modeling

    The predominant underwater noise associated with the construction 
of the Project results from impact and vibratory pile driving and 
drilling. Park City Wind employed JASCO Applied Sciences (USA) Inc. 
(JASCO) to conduct acoustic modeling to better understand sound fields 
produced during these activities (K[uuml]sel et al., 2022). The basic 
modeling approach is to characterize the sounds produced by the source, 
and determine how the sounds propagate within the surrounding water 
column. For impact pile driving, JASCO conducted sophisticated source 
and propagation modeling (as described below). For vibratory pile 
driving and drilling activities, JASCO applied in situ data to estimate 
source levels and applied a general practical spreading loss (15logR) 
assumption. To assess the potential for take from impact pile driving, 
JASCO also conducted animal movement modeling to estimate take; JASCO 
estimated species-specific exposure probability by considering the 
range- and depth-dependent sound fields in relation to animal movement 
in simulated representative construction scenarios. To assess the 
potential for take from vibratory pile driving and drilling, exposure 
modeling was not conducted. More details on these acoustic source 
modeling, propagation modeling and exposure modeling methods are 
described below.
    JASCO's Pile Driving Source Model (PDSM), a physical model of pile 
vibration and near-field sound radiation (MacGillivray, 2014), was used 
in conjunction with the GRL, Inc. Wave Equation Analysis of Pile 
Driving (GRLWEAP) 2010 wave equation model (Pile Dynamics, 2010) to 
predict source levels associated with impact pile driving activities 
(WTG and ESP foundation installation). The PDSM physical model computes 
the underwater vibration and sound radiation of a pile by solving the 
theoretical equations of motion for axial and radial vibrations of a 
cylindrical shell. This model is used to estimate the energy 
distribution per frequency (source spectrum) at a close distance from 
the source (10 m). Piles are modeled as a vertical installation using a 
finite-difference structural model of pile vibration based on thin-
shell theory. To model the sound emissions from the piles, the force of 
the pile driving hammers also had to be modeled. The force at the top 
of each monopile and jacket foundation pile was computed using the 
GRLWEAP 2010 wave equation model (GRLWEAP; Pile Dynamics, 2010), which 
includes a large database of simulated hammers. The forcing functions 
from GRLWEAP were used as inputs to the finite difference model to 
compute the resulting pile vibrations (see Figures 13-15 in Appendix A 
of Park City Wind's ITA application for the computed forcing 
functions). The sound radiating from the pile itself was simulated 
using a vertical array of discrete point sources. These models account 
for several parameters that describe the operation--pile type, 
material, size, and length--the pile driving equipment, and approximate 
pile penetration depth. The model assumed direct contact between the 
representative hammers, helmets, and piles (i.e., no cushioning 
material). For both jacket and monopile foundation models, the piles 
are assumed to be vertical and driven to a penetration depth of 50 m 
and 40 m, respectively.
    Park City Wind would use at least two noise abatement systems (NAS) 
during all pile driving and drilling associated with foundation 
installations and UXO/MEC detonations, such as a double bubble curtain 
or single bubble curtain and an encapsulated bubble or foam sleeve, to 
reduce sound levels. NAS, such as bubble curtains, are sometimes used 
to decrease the sound levels radiated from a source. Hence, 
hypothetical broadband attenuation levels of 0 dB, 6 dB, 10 dB, and 12 
dB were incorporated into the foundation source models to gauge effects 
on the ranges to thresholds given these levels of attenuation (Appendix 
G of the ITA application). Although four attenuation levels were 
evaluated, Park City Wind and NMFS anticipate that the noise 
attenuation system ultimately chosen will be capable of reliably 
reducing source levels by 10 dB; therefore, this assumption was carried 
forward in this analysis for monopile and jacket foundation pile 
driving installation, drilling activities, and UXO/MEC detonations. See 
the Proposed Mitigation section for more information regarding the 
justification for the 10-dB assumption.
    In addition to considering noise abatement, the amount of sound 
generated during pile driving varies with the energy required to drive 
piles to a desired depth and depends on the sediment resistance 
encountered. Sediment types with greater resistance require hammers 
that deliver higher energy strikes and/or an increased number of 
strikes relative to installations in softer sediment. Maximum sound 
levels usually occur during the last stage of impact pile driving where 
the greatest resistance is encountered (Betke, 2008). Key modeling 
assumptions for the monopiles and pin piles are listed in Table 10 
(additional modeling details and input parameters can be found in 
K[uuml]sel et al. (2022)). Hammer energy schedules for monopiles (12-m) 
and pin piles (4-m) are provided in Table 11, respectively, and the 
resulting broadband source level comparisons of the 12-m and 13-
monopiles are presented in Table 12. Decidecade spectral source levels 
for each pile type, hammer energy, and modeled location for summer 
sound speed profiles can be found in Appendix A of Park City Wind's ITA 
application (Figures 16 to 18).

[[Page 37648]]



                          Table 10--Key Piling Assumptions Used in the Source Modeling
----------------------------------------------------------------------------------------------------------------
                                             Maximum impact       Wall                     Seabed
              Foundation type                 hammer energy    thickness   Pile length  penetration   Number per
                                                  (kJ)            (mm)         (m)       depth (m)       day
----------------------------------------------------------------------------------------------------------------
12-m Monopile \1\.........................             6,000          200           95           40          1-2
4-m Jacket Pin Pile 2 3...................             3,500          100          100           50            4
----------------------------------------------------------------------------------------------------------------
\1\ A 12-m monopile using 6,000 kJ was considered representative of the other monopile approaches as the 13-m is
  unlikely to occur.
\2\ Jacket foundations each require the installation of three to four jacket securing piles, known as pin piles.
\3\ The bottom-frame foundation is similar to the jacket foundation, with the same maximum 4-m pile diameter,
  but with shorter piles and shallower penetration and was therefore not modeled separately in the acoustic
  assessment. It is assumed that the potential acoustic impact of the bottom-frame foundation installation is
  equivalent to or less than that predicted for the jacket foundation.


                                                      Table 11--Hammer Energy Schedules for Monopiles and Pin Piles Used in Source Modeling
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
           12-m monopile 5000 kJ hammer               13-m monopile 5000 kJ hammer        12-m monopile 6000 kJ hammer         4-m pin pile 3500 kJ hammer      13-m monopile 6000 kJ hammer \1\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                     Energy level                        Energy level                        Energy level                        Energy level
       Energy level (kJ)           Strike count          (kJ)          Strike count          (kJ)          Strike count          (kJ)          Strike count          (kJ)          Strike count
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1,000..........................  690.............  1,000...........  745.............  1,000...........  750.............  525.............  875.............  1,000...........  850
1,000..........................  1,930...........  1,000...........  2,095...........  2,000...........  1,250...........  525.............  1,925...........  2,000...........  1,375
2,000..........................  1,910...........  2,000...........  2,100...........  3,000...........  1,000...........  1000............  2,165...........  3,000...........  1,100
3,000..........................  1,502...........  3,000...........  1,475...........  45,000..........  1000............  3,500...........  3,445...........  4,500...........  1,100
5,000..........................  398.............  5,000...........  555.............  6,000...........  500.............  3,500...........  1,395...........  6,000...........  550
Total..........................  6,430...........  Total...........  6,970...........  Total...........  4,500...........  Total...........  9,805...........  Total...........  4,975
Strike Rate....................  30.0 bpm........  Strike Rate.....  30.0 bpm........  Strike Rate.....  25.0 bpm........  Strike Rate.....  30.0 bpm........  Strike Rate.....  27.6 bpm.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Due to the unlikely event Park City Wind installs a 13-m pile with a 6,000 kJ hammer, source levels were modeled to estimate the distances to mitigation zones; however, exposure modeling
  was not conducted for this scenario.


      Table 12--Broadband Impact Pile Driving Source Level Comparisons Between the 12-m and 13-m Monopiles
----------------------------------------------------------------------------------------------------------------
                                                           12-m monopile      13-m monopile
                                                        --------------------------------------    Source level
                Hammer energy level (kJ)                  Source level (dB   Source level (dB   difference (dB)
                                                                SPL)               SPL)
----------------------------------------------------------------------------------------------------------------
1,000..................................................             221.94             222.27               0.34
2,000..................................................             223.30             223.43               0.14
3,000..................................................             224.55             225.52               0.96
4,500..................................................             226.31             226.09               0.22
6,000..................................................             227.32             228.56               1.23
----------------------------------------------------------------------------------------------------------------

    For vibratory pile driving and drilling, source level modeling to 
estimate sound exposure levels was conducted based on extrapolations of 
source level data from smaller piles. Received SEL levels at 10 m for 
smaller, round steel piles driven with vibratory hammers were plotted 
as a function of pile diameter and fitted with a power function and 
then extrapolated for a 13-m diameter pile. While this method was 
applied to estimate SEL, the power function fit method described above 
for the received SPL at 10 m is poor, so an alternative approach to 
estimate SPL was derived. Noting that animals are not expected to 
experience a behavioral response at distances greater than 50 km 
(Dunlop et al. 2017a, 2017b), Park City Wind calculated the source 
level necessary to produce a received level of 120 dB at 50 km assuming 
practical spreading loss (15logR) resulting in a source level of 190.5 
dB SPL. The drilling source level was estimated based on drilling data 
collected in the Alaska Chukchi and Beaufort Sea (Austin et al., 2018). 
Resulting source levels assuming 10-dB attenuation from use of noise 
abatement (e.g., double bubble curtain) can be found in Table 13.

 Table 13--Assumed Source Levels for Vibratory Pile Driving and Drilling
                           of Foundation Piles
------------------------------------------------------------------------
                                   Source level SEL    Source level SPL
            Activity                     (dB)                (dB)
------------------------------------------------------------------------
Vibratory driving (13-m piles)..             \1\ 188               190.5
Drilling........................                 N/A           \2\ 183.3
------------------------------------------------------------------------
\1\ Extrapolation of data resulted in a source level (SEL) of 198 dB.
\2\ Source level reported in Austin et al