[Federal Register Volume 89, Number 124 (Thursday, June 27, 2024)]
[Proposed Rules]
[Pages 53708-53820]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-13770]



[[Page 53707]]

Vol. 89

Thursday,

No. 124

June 27, 2024

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 SouthCoast Wind Project Offshore 
Massachusetts; Proposed Rule

  Federal Register / Vol. 89 , No. 124 / Thursday, June 27, 2024 / 
Proposed Rules  

[[Page 53708]]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 217

[Docket No. 240605-0153]
RIN 0648-BM11


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to the SouthCoast 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 received a request from SouthCoast Wind Energy LLC 
(SouthCoast) (formerly Mayflower Wind Energy LLC), 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 Level B harassment, of small numbers of marine mammals 
over the course of five years (2027-2032) incidental to construction of 
the SouthCoast Wind Project (SouthCoast Project) offshore of 
Massachusetts within the Bureau of Ocean Energy Management (BOEM) 
Commercial Lease of Submerged Lands for Renewable Energy Development on 
the Outer Continental Shelf (OCS) Lease Area OCS-A 0521 (Lease Area) 
and associated Export Cable Corridors (ECCs). Specified activities 
expected to result in incidental take are pile driving (impact and 
vibratory), unexploded ordnance or munitions and explosives of concern 
(UXO/MEC) detonation, and 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. The regulations, if promulgated, would be effective April 
1, 2027 through March 31, 2032.

DATES: Comments and information must be received no later than July 29, 
2024.

ADDRESSES: A plain language summary of this proposed rule is available 
at https://www.regulations.gov/docket/ NOAA-NMFS-2024-0074. Submit all 
electronic public comments via the Federal e- Portal. Visit https://www.regulations.gov and type NOAA-NMFS-2024-0074 in the Rulemaking 
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 
https://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).
    A copy of SouthCoast'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 
below (see FOR FURTHER INFORMATION CONTACT).

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

SUPPLEMENTARY INFORMATION:

Purpose and Need for Regulatory Action

    This proposed rule, if promulgated, 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 SouthCoast Project within the Lease Area and along ECCs to landfall 
locations in Massachusetts. NMFS received a request from SouthCoast for 
5-year regulations and a LOA that would authorize take of individuals 
of 16 species of marine mammals by harassment only (4 species by Level 
A harassment and Level B harassment and 12 species by Level B 
harassment only) incidental to SouthCoast's construction activities. No 
mortality or serious injury is anticipated or proposed for 
authorization. Please see the Legal Authority for the Proposed Action 
section below for relevant definitions.

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). If such findings are made, NMFS must prescribe the 
permissible methods of taking; 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 monitoring 
and reporting of such takings.
    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:
     U.S. 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); 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(13); 
50 CFR 216.3);
     Incidental harassment, Incidental taking, and incidental, 
but not intentional, 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 (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(18); 50 CFR 216.3); and
     Level B harassment--any act of pursuit, torment, or 
annoyance which has the potential to disturb a marine mammal or marine 
mammal stock in the

[[Page 53709]]

wild by causing disruption of behavioral patterns, including, but not 
limited to, migration, breathing, nursing, breeding, feeding, or 
sheltering (16 U.S.C. 1362(18); 50 CFR 216.3).

Summary of Major Provisions Within the Proposed Rule

    The major provisions of this proposed rule are:
     Allowing NMFS to authorize, under a LOA, the take of small 
numbers of marine mammals by Level A harassment and/or Level B 
harassment incidental to the SouthCoast Project and prohibiting take of 
such species or stocks in any manner not permitted (e.g., mortality or 
serious injury);
     Establishing a seasonal moratorium on foundation 
installation within 20 kilometers (km) (12.4 miles (mi)) of the 30-m 
isobath on the western side of Nantucket Shoals which, for purposes of 
this proposed rule, is hereafter referred to as the North Atlantic 
Right Whale Enhanced Mitigation Area (NARW EMA), from October 16-May 
31, annually;
     Establishing a seasonal moratorium on foundation 
installation throughout the rest of the Lease Area January 1-May 15 and 
a restriction on foundation pile driving in December unless Southcoast 
requests and NMFS approves piling driving in December, which would 
require SouthCoast to implement enhanced mitigation and monitoring to 
minimize impacts to North Atlantic right whales (Eubalaena glacialis);
     Establishing enhanced North Atlantic right whale 
monitoring, clearance, and shutdown procedures SouthCoast must 
implement in the NARW EMA August 1-October 15, and throughout the rest 
of the Lease Area May 16-31 and December 1-31;
     Establishing a seasonal moratorium on the detonation of 
unexploded ordnance or munitions and explosives of concern (UXO/MEC) 
December 1-April 30 to minimize impacts to North Atlantic right whales;
     Requirements for UXO/MEC detonations to only occur if all 
other means of removal are exhausted (i.e., As Low As Reasonably 
Practicable (ALARP) risk mitigation procedure) and conducting UXO/MEC 
detonations during daylight hours only and limiting detonations to 1 
per 24 hour period;
     Conducting both visual and passive acoustic monitoring 
(PAM) by trained, NMFS-approved Protected Species Observers (PSOs) and 
PAM operators before, during, and after select in-water construction 
activities;
     Requiring training for all SouthCoast Project personnel to 
ensure marine mammal protocols and procedures are understood;
     Establishing clearance and shutdown zones for all in-water 
construction activities to prevent or reduce the risk of Level A 
harassment and to minimize the risk of Level B harassment, including a 
delay or shutdown of foundation impact pile driving and delay to UXO/
MEC detonation if a North Atlantic right whale is observed at any 
distance by PSOs or acoustically detected within certain distances;
     Establishing minimum visibility and PAM monitoring zones 
during foundation impact pile driving and detonations of UXO/MECs;
     Requiring use of a double bubble curtain during all 
foundation pile driving installation activities and UXO/MEC detonations 
to reduce noise levels to those modeled assuming a broadband 10 decibel 
(dB) attenuation;
     Requiring sound field verification (SFV) monitoring during 
pile driving of foundation piles and during UXO/MEC detonations to 
measure in situ noise levels for comparison against the modeled results 
and ensure noise levels assuming 10 dB attenuation are not exceeded;
     Requiring SFV during the operational phase of the 
SouthCoast Project;
     Implementing soft-starts during pile driving and ramp-up 
during the use of high-resolution geophysical (HRG) marine site 
characterization survey equipment;
     Requiring various vessel strike avoidance measures;
     Requiring various measures during fisheries monitoring 
surveys, such as immediately removing gear from the water if marine 
mammals are considered at-risk of interacting with gear;
     Requiring regular and situational reporting, including, 
but not limited to, information regarding activities occurring, marine 
mammal observations and acoustic detections, and sound field 
verification monitoring results; and
     Requiring monitoring of the North Atlantic right whale 
sighting networks, Channel 16, and PAM data as well as reporting any 
sightings to NMFS.
    Through adaptive management, NMFS Office of Protected Resources may 
modify (e.g., remove, revise, or add to) the existing mitigation, 
monitoring, or reporting measures summarized above and required by the 
LOA.
    NMFS must withdraw or suspend an LOA issued under these 
regulations, after notice and opportunity for public comment, if it 
finds the methods of taking or the mitigation, monitoring, or reporting 
measures are not being substantially complied with (16 U.S.C. 
1371(a)(5)(B); 50 CFR 216.106(e)). Additionally, failure to comply with 
the requirements of the LOA may result in civil monetary penalties and 
knowing violations may result in criminal penalties (16 U.S.C. 1375; 50 
CFR 216.106(g)).

National Environmental Policy Act (NEPA)

    On February 15, 2021, SouthCoast submitted a Construction and 
Operations Plan (COP) to BOEM for approval to construct and operate the 
SouthCoast Project, which has been updated several times since, as 
recently as September 2023. On November 1, 2021, BOEM published in the 
Federal Register a Notice of Intent (NOI) to prepare an Environmental 
Impact Statement (EIS) for the COP (86 FR 60270). On February 17, 2023, 
BOEM published and made its SouthCoast Draft Environmental Impact 
Statement (DEIS) for Commercial Wind Lease OCS-A 0521 available for 
public comment for 45 days, February 17, 2023 to April 3, 2023 (88 FR 
10377). On April 4, 2023, BOEM extended the public comment period by 15 
days through April 18, 2023 (88 FR 19986). Additionally, BOEM held 
three virtual public hearings on March 20, March 22, and March 27, 
2023.
    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 potential impacts on the human environment of 
the proposed action (i.e., promulgating the regulations and 
subsequently issuing a 5-year LOA to SouthCoast) and alternatives to 
that action. Accordingly, NMFS is a cooperating agency on BOEM's 
Environmental Impact Statement (EIS) and proposes to adopt the EIS, 
provided our independent evaluation of the document finds that it 
includes adequate information analyzing the effects on the human 
environment of promulgating the proposed regulations and issuing the 
LOA.
    Information in the SouthCoast ITA application, this proposed rule, 
and the BOEM EIS mentioned above collectively provide the environmental 
information related to proposed promulgation of these regulations and 
associated LOA for public review and comment. NMFS will review all 
comments submitted in response to this proposed rulemaking prior to 
concluding the NEPA process or making a final decision on the request 
for an ITA.

[[Page 53710]]

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

    The SouthCoast 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).
    SouthCoast's proposed project is listed on the Permitting 
Dashboard, where milestones and schedules related to the environmental 
review and permitting for the project can be found: https://www.permits.performance.gov/permitting-project/southcoast-wind-energy-llc-southcoast-wind.

Summary of Request

    On March 18, 2022, Mayflower Wind Energy LLC (Mayflower Wind) 
submitted a request for the promulgation of regulations and issuance of 
an associated 5-year LOA to take marine mammals incidental to 
construction activities associated with the Mayflower Wind Project 
offshore of Massachusetts in the Lease Area OCS-A-0521. On February 1, 
2023, Mayflower Wind notified NMFS that it changed its company name and 
project name to SouthCoast Wind Energy LLC and SouthCoast Wind Project, 
respectively. SouthCoast's request is for the incidental, but not 
intentional, taking of a small number of 16 marine mammal species 
(comprising 16 stocks) by Level B harassment (for all 16 species or 
stocks) and by Level A harassment (for four species or stocks). No 
serious injury or mortality is expected to result from the specified 
activities, nor is any proposed for authorization.
    In response to our questions and comments and following extensive 
information exchange between SouthCoast and NMFS, SouthCoast submitted 
revised applications on April 23, June 24, and August 16, 2022, and a 
final revised application on September 14, 2022, which NMFS deemed 
adequate and complete on September 19, 2022. On October 17, 2022, NMFS 
published a notice of receipt (NOR) of SouthCoast's adequate and 
complete application in the Federal Register (87 FR 62793), requesting 
comments and soliciting information related to SouthCoast's request 
during a 30-day public comment period. During the NOR public comment 
period, NMFS received comment letters from one member of the public, 
Seafreeze, Ltd, and two environmental non-governmental organizations: 
Conservation Law Foundation and Oceana. NMFS has reviewed all submitted 
material and has taken the material into consideration during the 
drafting of this proposed rule.
    Following publication of the NOR (87 FR 62793, October 17, 2022), 
NMFS further assessed potential impacts of SouthCoast's proposed 
activities on North Atlantic right whales that utilize foraging habitat 
within and near the Lease Area and consulted with SouthCoast to develop 
enhanced mitigation and monitoring measures that would reduce the 
likelihood of these potential impacts. On March 15, 2024, following 
extensive information exchange, SouthCoast submitted a North Atlantic 
Right Whale Enhanced Mitigation Plan and Monitoring Plan and revised 
application on March 15, 2024, which NMFS accepted on March 19, 2024.
    NMFS previously issued two Incidental Harassment Authorizations 
(IHAs) to Mayflower Wind and one IHA to SouthCoast Wind authorizing the 
taking of marine mammals incidental to marine site characterization 
surveys (using HRG equipment) of SouthCoast's Lease Area (OCS-A 0521) 
(see 85 FR 45578, July 29, 2020; 86 FR 38033, July 19, 2021; 88 FR 
31678, May 18, 2023). To date, SouthCoast has complied with all IHA 
requirements (e.g., mitigation, monitoring, and reporting). Information 
regarding SouthCoast's monitoring results, which were utilized in take 
estimation, may be found in the Estimated Take section, and the full 
monitoring reports can be found on NMFS' website: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable.
    On August 1, 2022, NMFS announced proposed changes to the existing 
North Atlantic right whale vessel speed regulations to further reduce 
the likelihood of mortalities and serious injuries to endangered right 
whales from vessel collisions, which are a leading cause of the 
species' decline and a primary factor in an ongoing Unusual Mortality 
Event (87 FR 46921). Should a final vessel speed rule be promulgated 
and become effective during the effective period of these proposed 
regulations (or any other MMPA incidental take authorization), the 
authorization holder would be required to comply with any and all 
applicable requirements contained within such final vessel speed 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 such rule. Alternatively, where measures in this or 
any other MMPA authorization are more restrictive or protective than 
those in any final vessel speed rule, the measures in the MMPA 
authorization would remain in place. The responsibility to comply with 
the applicable requirements of any vessel speed rule would become 
effective immediately upon the effective date of any final vessel speed 
rule and, when notice is published of the effective date, NMFS would 
also notify SouthCoast if the measures in such speed rule were to 
supercede any of the measures in the MMPA authorization.

Description of the Specified Activities

Overview

    SouthCoast has proposed to construct and operate an up to 2,400 
megawatt (MW) offshore wind energy facility (SouthCoast Project) in 
state and Federal waters in the Atlantic Ocean in Lease Area OCS-A-
0521. This lease area is located within the Massachusetts Wind Energy 
Area (MA WEA), 26 nautical miles (nm, 48 km) south of Martha's Vineyard 
and 20 nm (37 km) south of Nantucket, Massachusetts. Development of the 
offshore wind energy facility would be divided into two projects, each 
of which would be developed in separate years. Project 1 and Project 2 
would occupy the northeastern and southwestern halves (approximately) 
of the Lease Area, respectively. Each Project would have the potential 
to generate approximately 1,200 MW of renewable energy. Once 
operational, SouthCoast would allow the State of Massachusetts to 
advance Federal and State offshore wind targets as well as reduce 
greenhouse gas emissions, increase grid reliability, and support 
economic development and growth in the region.
    The SouthCoast Project would consist of several different types of 
permanent offshore infrastructure: wind turbine generators (WTGs), 
offshore substation platforms (OSPs), associated WTG and OSP 
foundations, inter-array and ECCs, and offshore cabling. Onshore 
substation and converter stations, onshore interconnection routes, and 
operations and maintenance (O&M) facilities are also planned. There are 
149 positions in OSP foundations (totaling no more than 149) would be 
installed.

[[Page 53711]]

The number of WTG foundations installed would vary by project. 
SouthCoast has not yet determined the exact number of OSPs necessary to 
support each project, but the total across projects would not exceed 
five. Project 1 would include up to 85 WTG foundations, and Project 2 
would include up to 73 WTG foundations for a maximum of 147 WTG 
foundations for both Project 1 and Project 2. Project 1 foundations 
would be installed in two distinct areas. Subject to extensive 
mitigation, including extended seasonal restrictions and monitoring, 
SouthCoast would install up to 54 foundations within the NARW EMA, 
defined as the northeastern portion of the lease area within 20 km (9.3 
mi) of the 30-m (98.4 ft) isobath along the western side of Nantucket 
Shoals (see Figure 2 in the Specified Geographical Area section for 
more detail). The remaining foundations for Project 1 (out of a maximum 
of 85) would be installed in positions immediately southwest of the 
NARW EMA.
    SouthCoast is considering three foundation types for WTGs and OSPs: 
monopile, piled jacket, and suction-bucket jacket. SouthCoast would 
install up to two different foundation types for WTGs (i.e., piled 
jacket and monopiles), and potentially a third concept for OSPs (e.g., 
suction bucket jacket). However, due to economic and technical 
infeasibility, suction-bucket jackets are no longer under consideration 
for Project 1. Geotechnical investigations at Project 2 foundation 
locations are ongoing, and SouthCoast will need to assess the data to 
determine whether it would be feasible to install suction-bucket jacket 
foundations, rather than monopile or jacket foundations. However, due 
to predicted installation complexities, this is not the preferred 
foundation type. If suction bucket foundations are selected for Project 
2, pile driving would not be necessary.
    SouthCoast is considering multiple installation scenarios for each 
project, which differ by foundation type and number, and installation 
method. For Project 1, SouthCoast plans to install either all monopile 
WTG (Project 1, Scenario 1; P1S1: 71 WTGs) or pin-piled jacket (Project 
1, Scenario 2; P1S2: 85 WTGs) foundations by impact pile driving only. 
For Project 2, unless suction bucket jackets are selected as the 
preferred type, foundation installation would also include either all 
monopile or all piled jacket WTG foundations, which would be installed 
using impact pile driving only (Project 2, Scenario 1; P2S1: 68 WTGs) 
or a combination of vibratory and impact (Project 2, Scenario 2; P2S2, 
73 WTGs; Project 2 Scenario 3; P2S3 62 WTGs) pile driving. Each WTG and 
OSP would be supported by a single foundation. OSP monopile or piled 
jacket foundations would be installed using only impact pile driving. 
SouthCoast is considering three OSP designs: modular, integrated, and 
DC-converter. Should they elect to install piled jacket foundations to 
support OSPs, the number of jacket legs and pin piles would vary 
depending on the OSP design. SouthCoast currently identifies 
installation of one DC-converter OSP per project, each supported by a 
piled jacket foundation, as the most realistic scenario.
    Inter-array cables will transmit electricity from the WTGs to the 
OSP. Export cables would transmit electricity from each OSP to a 
landfall site. All offshore cables will connect to onshore export 
cables, substations, and grid connections, which would be located at 
landfall locations. SouthCoast is proposing to develop one preferred 
ECC for both Project 1 and Project 2, making landfall and 
interconnecting to the ISO New England Inc. (ISO-NE) grid at Brayton 
Point, in Somerset, Massachusetts (i.e., the Brayton Point Export Cable 
Corridor (Brayton Point ECC)). For Project 2, SouthCoast is proposing 
an alternative export cable corridor which, if utilized, would make 
landfall and interconnect to the ISO-NE grid in the town of Falmouth, 
MA (the Falmouth ECC) in the event that technical, logistical, grid 
interconnection, or other unforeseen challenges arise during the design 
and engineering phase that prevent Project 2 from making 
interconnection at Brayton Point.
    Specified activities would also include temporary installation of 
up to four nearshore gravity-based structures (e.g., gravity cell or 
gravity-based cofferdam) and/or dredged exit pits to connect the 
offshore export cables to onshore facilities; vessel-based site 
characterization and assessment surveys using high-resolution 
geophysical active acoustic sources with frequencies of less than 180 
kilohertz (kHz) (HRG surveys); detonation of up to 10 unexploded 
ordnances or Munitions and Explosives of Concern (UXO/MEC) of different 
charge weights; several types of fishery and ecological monitoring 
surveys; site preparation work (e.g., boulder removal); the placement 
of scour protected; trenching, laying, and burial activities associated 
with the installation of the export cable from OSPs to shore-based 
switching and substations and inter-array cables between turbines; 
transit within the Lease Area and between ports and the Lease Area to 
transport crew, supplies, and materials to support pile installation 
via vessels; and WTG operation.
    Based on the current project schedule, SouthCoast anticipates WTGs 
would become operational for Project 1 beginning in approximately Q2 
2029 and Project 2 by Q4 2031, after installation is completed and all 
necessary components, such as array cables, OSPs, ECCs, and onshore 
substations are installed. Turbines would be commissioned individually 
by personnel on location, so the number of commissioning teams would 
dictate how quickly turbines would become operational. SouthCoast 
expects that all turbines will be commissioned by Q4 2031.
    Marine mammals exposed to elevated noise levels during impact and 
vibratory pile driving during foundation installation, detonations of 
UXO/MECs, or HRG 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

    The specified activities would occur over approximately 6 years, 
starting in the fourth quarter of 2026 and continuing through the end 
of 2031. SouthCoast anticipates that the specified activities with the 
potential to result in take by harassment of marine mammals would begin 
in the second quarter of 2027 and occur throughout all 5 years of the 
proposed regulations which, if issued, would be effective from April 1, 
2027-March 31, 2032.
    The general schedule provided in table 1 includes all of the major 
project components, including those that may result in harassment of 
marine mammals (i.e., foundation installation, HRG surveys, and UXO/MEC 
detonation) and those that are not expected to do so (shown in 
italics). Projects 1 and 2 will be developed in separate years, which 
may not be consecutive. To allow flexibility in the final design and 
during the construction period, SouthCoast has not identified specific 
years in which each Project would be installed.

[[Page 53712]]



    Table 1--Estimated Activity Schedule To Construct and Operate the
                           SouthCoast Project
------------------------------------------------------------------------
       Specified activity         Estimated schedule    Activity timing
------------------------------------------------------------------------
HRG Surveys.....................  Q2 2027-Q3 2031...  Any time of the
                                                       year, up to 112.5
                                                       days per year
                                                       during
                                                       construction of
                                                       Project 1 and
                                                       Project 2, and up
                                                       to 75 days per
                                                       year during non-
                                                       construction
                                                       years.
Scour Protection Pre- or Post-    Q1 2027-Q3 2029...  Any time of the
 Installation.                                         year.
WTG and OSP Foundation            Q2-Q4 2028 or Q2-   Approximately 6
 Installation, Project 1.          Q4 2029\1\ \2\.     months.
WTG and OSP Foundation            Q2-Q4 2030 \1\ \2\  Approximately 6
 Installation, Project 2.          \3\.                months.
Horizontal Directional Drilling   Project 1 Q4 2026-  Approximately 6
 at Cable Landfall Sites.          Q1 2027.            months per
                                  Project 2 Q4 2029-   project.
                                   Q1 2030.
UXO/MEC Detonations.............  Q2-Q4 2028, 2029,   Up to 5 days for
                                   and 2030 \4\.       Project 1 and up
                                                       to 5 days for
                                                       Project 2. No
                                                       more than 10 days
                                                       total.
Inter-array Cable Installation..  Project 1: 2028-    Project 1: up to
                                   2029.               16 months.
                                  Project 2: 2029-    Project 2: up to
                                   2030.               12 months.
Export Cable Installation and     Project 1: 2027-    Project 1: up to
 Termination.                      2029.               30 months.
                                  Project 2: 2029-    Project 2: up to
                                   2030.               12 months.
Fishery Monitoring Surveys......  Before, during,     Any time of year.
                                   and after
                                   construction of
                                   Projects 1 and 2.
                                 ---------------------------------------
Turbine Installation and          Initial turbines operational 2030, all
 Operation.                        turbines operational by 2032.
------------------------------------------------------------------------
\1\ SouthCoast does not currently know in which of these years Project 1
  and Project 2 construction would occur but estimates that each Project
  would be completed in a single year (2 years total).
\2\ NMFS is proposing seasonal restriction mitigation measures that
  would limit pile driving to June 1 through October 15 in the NARW EMA
  and May 16 through December 31 in the rest of the Lease Area (although
  proposing requiring NMFS' prior approval to install foundations in
  December).
\3\ Should SouthCoast decide to install suction bucket foundations for
  Project 2, installation would occur Q2 2030-Q2 2031. This activity
  would not be seasonally restricted because installation of this
  foundation type does not require pile driving.
\4\ NMFS is proposing seasonal restriction mitigation measures UXO/MEC
  detonations from December 1 through April 30.
\5\ Activities in italics are not expected to result in incidental take
  of marine mammals.

Specific Geographical Region

    Most of SouthCoast'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\ (64,247,399.2 acres), spanning from 
Cape Hatteras in the south to the Gulf of Maine in the north. More 
specifically, the Lease Area and ECC would be located within the Mid-
Atlantic Bight subarea of the NES LME, which extends between Cape 
Hatteras, North Carolina, and Martha's Vineyard, Massachusetts, and 
eastward into the Atlantic to the 100-m (328.1 ft) isobath.
    The Lease Area and ECCs are located within the Southern New England 
(SNE) sub-region of the Northeast U.S. Shelf Ecosystem, at the 
northernmost end of the Mid-Atlantic Bight (MAB), which is distinct 
from other regions based on differences in productivity, species 
assemblages and structure, and habitat features (Cook and Auster, 
2007). Weather-driven surface currents, tidal mixing, and estuarine 
outflow all contribute to driving water movement through the area 
(Kaplan, 2011), which is subjected to highly seasonal variation in 
temperature, stratification, and productivity. The Lease Area, OCS-A 
0521, is part of the Massachusetts Wind Energy Area (MA WEA) (3,007 
square kilometers (km\2\) (742,974 acres)) (Figure 1). Within the MA 
WEA, the Lease Area covers approximately 516 km\2\ (127, 388 acres) and 
is located approximately 30 statute miles (mi) (26 nm; 48 km) south of 
Martha's Vineyard, Massachusetts, and approximately 23 mi (20 nm, 37 
km) south of Nantucket, Massachusetts. At its closest point to land, 
the Lease Area is approximately 45 mi (39 nm, 72 km) south from the 
mainland at Nobska Point in Falmouth, Massachusetts.
    During construction, the Project will require support from 
temporary construction laydown yard(s) and construction port(s). The 
operational phase of the Project will require support from onshore O&M 
facilities. While a final decision has not yet been made, SouthCoast 
will likely use more than one marshalling port for the SouthCoast 
Project. The following ports are under consideration: New Bedford, MA; 
Fall River, MA; South Quay, RI; Salem Harbor, MA; Port of New London, 
CT; Port of Charleston, SC; Port of Davisville, RI; Sparrows Point 
Port, Maryland; and Sheet Harbor, Canada.
BILLING CODE 3510-22-P

[[Page 53713]]

[GRAPHIC] [TIFF OMITTED] TP27JN24.000

    The Brayton Point ECC and the Falmouth ECC would traverse Federal 
and state territorial waters of Massachusetts and Rhode Island, making 
landfall at Brayton Point in Somerset, Massachusetts or at Falmouth, 
Massachusetts, respectively. Within the Brayton Point ECC, up to six 
submarine offshore export cables, including up to four power cables and 
up to two dedicated communications cables, would be installed from one 
or more OSPs within the lease area in Federal waters and run through 
the Sakonnet River, make intermediate landfall on Aquidneck Island in 
Portsmouth, Rhode Island, which includes an underground onshore export 
cable route, and then into Mount Hope Bay to make landfall at Brayton 
Point in Somerset, Massachusetts. Within the Falmouth export cable 
corridor, up to five submarine offshore export cables, including up to 
four power cables and up to one dedicated communications cable, would 
be installed from one or more OSPs within the Lease Area and run 
through Muskeget Channel into Nantucket Sound in Massachusetts state 
waters to

[[Page 53714]]

make landfall in Falmouth, Massachusetts.
    As described in further detail below, SouthCoast proposed 
mitigation and monitoring measures that would apply throughout the 
Lease Area, as well as enhanced measures applicable to a portion of the 
Lease Area that overlaps with the NARW EMA. The 30-m (98.4 ft)) isobath 
represents bathymetry defining the edge of Nantucket Shoals and 
corresponds with the predicted location of tidal mixing fronts in this 
region (Simpson and Hunter, 1974; Wilkin, 2006) and observations of 
high productivity and North Atlantic right whale foraging (Leiter et 
al., 2017; White et al., 2020).

[[Page 53715]]

[GRAPHIC] [TIFF OMITTED] TP27JN24.001

BILLING CODE 3510-22-C
    Water depths in the project area (which includes the lease area, 
cable corridors, vessel transit lanes and ensonified area above NMFS 
thresholds) span from less than 1 meter ((m); 3.28 feet (ft)), near the 
landfall sites, to approximately 64 m at the deepest location in the 
lease area. Water depths in the lease area, in relation to Mean Lower 
Low Water (MLLW), range from approximately 37.1 to 63.5 m (121.7-208.3 
ft). Of the 149 foundation locations, 101 are located in waters depths 
less than 54 m (177 ft) and the remaining 48 are located in water

[[Page 53716]]

depths from 54-64 m (177-210 ft). Water depths along the Brayton Point 
and Falmouth ECCs range from 0-41.5 m (0-136.2 ft) MLLW. The cable 
landfall construction areas would be approximately 2.0-10.0 m (6.6-32.8 
ft) deep in Somerset and 5.0 to 8.0 m (16.4-26.3 ft) deep in Falmouth.
    Geological conditions in the project area, including sediment 
composition, are the result of glacial processes. The pattern of 
sediment distribution in the Mid-Atlantic Bight is relatively simple. 
The continental shelf south of New England is broad and flat, dominated 
by fine-grained sediments. Sediment composition is primarily dominated 
by sand, but varies by location, comprising various sand grain sizes 
sand to silt. Seafloor conditions in the Lease Area align with the 
findings at nearby locations in the RI/MA and MA WEAs showing little 
relief and low complexity (i.e., mostly homogeneous) (section 
6.6.1.6.1, SouthCoast Wind COP, 2024; Epsilon, 2018). Data collected as 
part of SouthCoast's benthic surveys indicate varying levels of 
surficial sediment mobility throughout the Lease Area and ECCs, 
evidenced by the ubiquitous presence of bedforms (ripples), both large 
and small. The deeper shelf waters of the Lease Area and ECCs are 
characterized by predominantly rippled sand and soft bottoms. Where the 
Falmouth ECC would enter Muskeget Channel and Nantucket Sound, the 
surface sediments become coarser sand with gravel and hard bottoms. The 
coarser sediments represent reworked glacial materials. No large-scale 
seabed topographic features or bedforms were found within the Lease 
Area (SouthCoast Wind COP, 2024). Moraine deposits related to the 
formation of Martha's Vineyard and Nantucket Island have resulted in 
boulder fields along portions of both ECCs (Baldwin et al., 2016; 
Oldale, 1980). The Brayton Point ECC also crosses moraine features 
represented by the Southwest Shoal off Martha's Vineyard and Browns 
Ledge off the Elizabeth Island in Rhode Island Sound (section 3.1, 
SouthCoast Wind COP, 2024).
    The species that inhabit the benthic habitats of the Lease Area and 
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 
organisms; e.g., barnacles, anemones, tunicates). These organisms are 
important food sources for several commercially important northern 
groundfish species.
    The SouthCoast Lease Area is located adjacent to Nantucket Shoals, 
a broad shallow and sandy shelf that extends southeast of Nantucket 
Island. Waters from the Gulf of Maine, the Great South Channel, and 
Nantucket Sound converge in this area, creating a well-mixed water 
column throughout the year (Limeburner and Beardsley, 1982).
    The shoals area has an underwater dunelike topography and strong 
tidal currents (PCCS, 2005). Surface currents become stronger during 
the spring and summer as heating and stratification increase (Brookes, 
1992; PCCS, 2005). Due to wind and tidal mixing, a persistent tidal 
front occurs along the western edge of Nantucket Shoals, (Chen et al., 
1994a; b). This frontal region typically spans approximately 10-20 km 
(6.2-12.4 mi) (Potter and Lough, 1987; Lough and Manning, 2001; Ullman 
and Cornillon, 2001; White and Veit, 2020), with its strength and 
cross-isobath flow potentially influenced by regional winds (Ullman and 
Cornillon, 2001). The estimated location of this front varies from the 
50-m (164-ft) isobath to inshore of the 30-m (98.4-ft) isobath (Ullman 
and Cornillon, 2001; Wilkin, 2006).
    The ecology of the Nantucket Shoals region is unique in that it 
supports recurring enhanced aggregations of zooplankton that provide 
prey for North Atlantic right whales and other species migrating to the 
region to forage (Quintana-Rizzo et al., 2021). The region is 
characterized by complex hydrodynamics and ecology. The hydrodynamics 
of this region result from processes at variable spatial scales that 
extend from oceanic (Gulf Stream warm core rings) to local (tidal 
mixing) and timescales of seasonal (stratification) to decadal 
(National Academy of Sciences (NAS), 2023). The physical oceanographic 
and bathymetric features (i.e., shallow, well-lit, well-mixed) provide 
for year-round high phytoplankton biomass. Strong tidal currents create 
thorough mixing of the water column, distributing nutrients, which 
enhances and concentrates productivity of phytoplankton and zooplankton 
(PCCS, 2005; White et al., 2020). High productivity in the area is also 
stimulated by a local tidal pump generated by the tidal dissipation 
between Nantucket Sound and the shoals so significantly that this tidal 
pump creates one of the largest tidal dispensation areas in New England 
(Chen et al., 2018; Quintana-Rizzo et al., 2021). Hydrographic 
features, such as circulation patterns and tides, result in the flow of 
zooplankton into area from source regions outside, rather than 
increased primary productivity due to upwelling (Kenney and Wishner, 
1995; PCCS, 2005). The persistent frontal zone on the western side of 
Nantucket Shoals, with an estimated location that varies from the 50-m 
isobath to inshore of the 30-m (98.4-ft) isobath (Ullman and Cornillon, 
2001; Wilkin, 2006), aggregates zooplankton prey whose distributions 
are dependent on hydrodynamics and frontal features (White et al., 
2020). These aggregations not only draw North Atlantic right whales but 
also other marine vertebrates that forage on the resulting dense prey 
patches, such as schooling fish and sea ducks and white-winged scooters 
(Scales et al., 2014; White et al., 2020). The frontal zone is also 
associated with a wide diversity of mollusk, crustacean, and echinoderm 
species, as well as surf clams, quahogs, and ``intense winter 
aggregations'' of Gammarid amphipods (White et al., 2020).

Detailed Description of Specified Activities

    Below, we provide detailed descriptions of SouthCoast's specified 
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. For more information beyond that provided here, see 
SouthCoast's ITA application.
WTG and OSP Foundation Installation
    SouthCoast proposes to install a maximum of 149 foundations 
composed of a combination of up to 147 WTG and up to 5 OSP foundations, 
conforming to spacing on a 1 nm x 1 nm (1.9 km x 1.9 km) grid layout, 
oriented east-west and north-south). SouthCoast would be restricted 
from pile driving in the NARW EMA from October 16 through May 31 and 
January 1 through May 15 in the remainder of the Lease Area. SouthCoast 
should avoid pile driving in December (i.e., it should not be planned), 
and it may only occur with prior approval by NMFS and implementation of 
enhanced mitigation and monitoring measures. SouthCoast must notify 
NMFS in writing by September 1 of that year, indicating that 
circumstances are expected to necessitate pile driving in December.
    Project 1 would include installation of up to 86 foundations (85 
WTG, 1 OSP), including 54 foundations located within the NARW EMA and 
up to 32 foundations immediately to the southwest of the NARW EMA. 
Foundation installation would begin in the northeast portion of the 
Project 1

[[Page 53717]]

area (Figure 2) no earlier than June 1, 2028, given NMFS' proposed pile 
driving seasonal restriction. By installing foundations in this portion 
of the Project 1 area first (beginning June 1), SouthCoast would begin 
conducting work closest to Nantucket Shoals and then progressing 
towards the southwest and moving away from Nantucket Shoals. SouthCoast 
would complete foundation installations in the NARW EMA by October 15, 
prior to when North Atlantic right whale occurrence is expected to 
begin increasing in eastern southern New England (e.g., Davis et al., 
2024). The number of WTG foundations available for Project 2 depends on 
the final footprint for Project 1, but the combined number for both 
projects would not exceed 147. SouthCoast would install Project 2 
foundations in the portion of the Lease Area southwest of Project 1.
    SouthCoast would install foundations using impact pile driving only 
for Project 1 and a combination of impact and vibratory pile driving 
for Project 2. Vibratory setting, a technique wherein the pile is 
initially installed with a vibratory hammer until an impact hammer is 
needed, is particularly useful when soft seabed sediments, such as 
those previously described for SouthCoast's project area in the 
Specified Geographic Region section, are not sufficiently stiff to 
support the weight of the pile during the initial installation, 
increasing the risk of `pile run' (i.e., where a pile sinks rapidly 
through seabed sediments). Piles subject to 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, whereby 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. This can be 
accomplished using a single installation vessel equipped with both 
hammer types or two separate vessels, each equipped with either the 
vibratory or impact hammer.
    For each Project, SouthCoast expects to install foundations within 
a 6-month period each year for two years. However, it is possible that 
foundation installation could continue into a second year for either 
Project, depending on construction logistics and local and 
environmental conditions that may influence SouthCoast's ability to 
maintain the planned construction schedule. Regardless of shifts in the 
construction schedule, the seasonal restrictions on pile driving would 
apply.
    SouthCoast has proposed to initiate pile driving any time of day or 
night. Once construction begins, SouthCoast would proceed as rapidly as 
possible while implementing 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 at night. SouthCoast is 
currently conducting a review of available, systematically collected 
data on the efficacy of technology to monitor (visually and 
acoustically) marine mammals during nighttime and in reduced visibility 
conditions during daytime. Should SouthCoast submit, and NMFS approve, 
an Alternative Monitoring Plan (which includes nighttime pile driving 
monitoring), pile driving may be initiated at night.
    While the majority of foundation installations would be sequential 
(i.e., one at a time), SouthCoast proposed concurrent pile driving 
(i.e., two installation vessels installing foundations at the same 
time) for a small number of foundations, limited to the few days on 
which both OSP and WTG foundations are installed simultaneously. Using 
a single installation vessel, SouthCoast anticipates that a maximum of 
two monopile foundations could be sequentially driven into the seabed 
per day, assuming 24-hour pile driving operations; however, 
installation of one monopile per day is expected to be more common and 
the installation schedule assumed for the take estimation analyses 
reflects this (table 2). For jacket foundation installation, SouthCoast 
estimates that no more than four pin piles (supporting one jacket 
foundation) could be installed per 24 hours on days limited to 
sequential installation. SouthCoast anticipates that, on days with 
concurrent pile driving using two installation vessels, up to, 1) two 
WTG monopiles or four WTG pin piles (by one installation vessel) and, 
2) four OSP pin piles (by a second vessel, working simultaneously) 
could be installed in 24 hours.
    As described previously, SouthCoast is considering several 
foundation options. For Project 1, SouthCoast is considering 
installation of two types of WTG foundations, monopile or pin-piled 
jacket, which would be installed by impact pile driving only. 
SouthCoast is also considering these foundation types for Project 2 but 
may use a combination of vibratory and/or impact pile driving for their 
installation. Finally, suction-bucket jacket foundations may provide an 
alternative to monopile and pin-piled jacket foundations to support 
WTGs for Project 2. However, installing this third foundation type does 
not require impact or vibratory pile driving, and it is not anticipated 
to result in noise levels that would cause harassment to marine 
mammals. Therefore, suction-bucket jacket foundations are not discussed 
further beyond the brief explanation below.
    Although considering three foundation types for Projects 1 and 2, 
for the purposes of estimating the maximum impacts to marine mammals 
that could occur incidental to WTG and OSP foundation installation, 
SouthCoast assumed WTGs would be supported by monopile or pin-piled 
jacket foundations and that OSPs would be supported by pin-piled jacket 
foundations. For both Project 1 and Project 2 acoustic and exposure 
modeling of the potential acoustic impacts resulting from installation 
of monopiles and pin piles (see Estimated Take section), SouthCoast 
proposed multiple WTG and OSP foundation installation scenarios for 
Projects 1 and 2, distinguished by foundation type and number, 
installation method (i.e., impact only; vibratory and impact pile 
driving), order (i.e., sequential or concurrent) and construction 
schedule (table 2).

[[Page 53718]]



                                                            Table 2--Potential Installation Scenarios for Project 1 and Project 2 \1\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                      Number of piles
 
                                         ------------------------------------------------------------------------
Installation order and method              9/16-m monopile   9/16-m monopile   4.5-m pin piles   4.5-m pin piled                         Total foundations                            Total days
                                                     1/day             2/day  WTG jacket piles        OSP jacket
                                                                                         4/day             4/day
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                     Project 1 (IMPACT ONLY)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                   Project 1 Scenario 1 (P1S1)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sequential (IMPACT).....................                44                24  ................  ................  71 WTG........................  1 OSP.........................              59
Concurrent (IMPACT).....................                 3  ................  ................                12
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                   Project 1 Scenario 2 (P1S2)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sequential (IMPACT).....................  ................  ................               324  ................  85 WTG........................  1 OSP.........................              85
Concurrent (IMPACT).....................  ................  ................                16                16
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                 Project 2 (VIBE AND/OR IMPACT)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                   Project 2 Scenario 1 (P2S1)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sequential (IMPACT).....................                35                30  ................  ................  68 WTG........................  1 OSP.........................              53
Concurrent (IMPACT).....................                 3  ................  ................                12
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                   Project 2 Scenario 2 (P2S2)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sequential (IMPACT).....................                 3  ................  ................  ................  73 WTG........................  1 OSP.........................              49
Sequential (VIBE+IMPACT)................                19                48  ................  ................
Concurrent (IMPACT).....................                 3  ................  ................                12
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                   Project 2 Scenario 3 (P2S3)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sequential (IMPACT).....................  ................  ................                40  ................  62 WTG........................  1 OSP.........................              62
Sequential (VIBE+IMPACT)................  ................  ................               192  ................
Concurrent (IMPACT).....................  ................  ................                16                16
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Installation schedules vary based on foundation type (WTG monopile or pin-piled jacket, OSP pin-piled jacket) and number, installation method (impact, or combination of vibratory and
  impact), and installation order (sequential or concurrent).

    As described previously, SouthCoast considered two WTG foundation 
installation scenarios for Project 1 and one scenario for Project 2 
that would employ impact pile driving only (I), and two scenarios for 
Project 2 that would require a combination of vibratory and impact pile 
driving (V/I):
 Project 1
[cir] Scenario 1 (I): 71 monopile WTG, 1 pin-piled jacket OSP
[cir] Scenario 2 (I): 85 pin-piled jacket WTG, 1 pin-piled jacket OSP
 Project 2
[cir] Scenario 1 (I): 68 monopile WTG, 1 pin-piled jacket OSP
[cir] Scenario 2 (V/I): 73 monopile WTG, 1 pin-piled jacket OSP
[cir] Scenario 3 (V/I): 62 pin-piled jacket WTG, 1 pin-piled jacket OSP

    For each Project, only one scenario would be implemented. For 
example, SouthCoast could choose to install Scenario 1 for Project 1 
(P1S1; 71 monopile WTG foundations, 1 pin-piled jacket OSP foundation) 
and Scenario 1 for Project 2 (P2S1; 68 monopile WTG foundations, 1 pin-
piled jacket OSP foundation) for a total of 139 WTG monopile and 2 OSP 
pin-piled jacket foundations, or 141 foundations overall (table 2). 
Alternatively, SouthCoast could install Scenario 2 for Project 1 (P1S2; 
85 WTG pin-piled jacket foundations, and 1 OSP pin-piled jacket) and 
Scenario 3 for Project 2 (P2S3; 62 pin-piled jacket foundation, 1 pin-
piled jacket OSP foundation), for a total of 147 WTG and 2 OSP 
foundations (or 149 foundations overall). Both of these combinations 
fall within SouthCoast's PDE, which specifies that SouthCoast would 
install no more than up to 147 WTG foundations and up to 5 OSP 
foundations. Given this limitation, there are Project 2 scenarios that 
can not be combined with scenarios for Project 1 because the total WTG 
foundation number would exceed 147 (i.e., the total number of WTG 
foundations would be 153 should SouthCoast combine the Project 1 
Scenario 2 (85 pin-piled jacket WTG foundations) with Project 2 
Scenario 1 (68 monopile WTG foundations) or 158 if combined with 
Project 2 Scenario 2). Thus, SouthCoast's selection of a scenario for 
Project 2 will depend on their scenario choice for Project 1.
WTG Foundations

Monopile

    SouthCoast proposed three scenarios that include monopile 
installations to support WTGs. A monopile foundation normally consists 
of a single steel tubular section with several sections of rolled steel 
plate welded together. Secondary structures on each WTG monopile 
foundation would include a boat landing or alternative means of safe 
access, ladders, a crane, and other ancillary components. Figure 3 in 
SouthCoast's application provides a conceptual example of a monopile. 
SouthCoast would install up to 147 WTG monopile foundations with a 
maximum diameter tapering from 9 m (2.7 ft) above the waterline to 16 m 
(52.5 ft) below the waterline (\9/16\-m monopile). A typical impact 
pile driven monopile installation sequence begins with transport of the 
monopiles either directly to the Lease Area 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 impact hammer is then lifted on top of the pile and pile 
driving commences with a 20-minute minimum soft-start, where lower 
hammer energy is used at the beginning of each pile installation to 
allow marine mammal and prey to move away from the sound source before 
noise levels increase to the maximum extent. Piles are driven until the 
target

[[Page 53719]]

embedment depth is met, then the pile hammer is removed and the 
monopile is released from the pile gripper. SouthCoast would install 
WTG monopiles using an impact pile driver with a maximum hammer energy 
of 6,600 kJ (model NNN 6600) for a total of 7,000 strikes (including 
soft-start hammer strikes) at a rate of 30 strikes per minute to a 
total maximum penetration depth of 50 m (164 ft). As described 
previously, for pile installations utilizing vibratory pile driving as 
well, this impact installation sequence would be preceded by use of a 
vibratory hammer to drive the pile to a depth that is sufficient to 
fully support the structure before beginning the soft-start and 
subsequent impact hammering. For these piles, SouthCoast would use a 
vibratory hammer (model HX-CV640) followed by a maximum of 5,000 impact 
hammer strikes (including soft-start) using the same hammer and 
parameters specified above.
    SouthCoast is proposing to install the majority of monopile 
foundations consecutively using a single vessel and on a small number 
of days, concurrently with OSP piled jacket pin piles using two vessels 
(see Dates and Duration section). Under typical conditions, impact 
installation of a single monopile foundation is estimated to require up 
to 4 hours of active impact pile driving (7,000 strikes/30 strikes per 
minute equals approximately 233 minutes, or 3.9 hours), which can occur 
either in a continuous 4-hour interval or intermittently over a longer 
time period. For installations requiring vibratory and impact pile 
driving, the installation duration is also expected to last 
approximately 4 hours, beginning with 20 minutes of active vibratory 
driving, followed by short period during which the hammer set-up would 
be changed from vibratory to impact, after which impact installation 
would begin with a 20-minute soft-start (5,000 strikes/30 strikes per 
minute equals approximately 167 minutes, or 2.8 hours). Following 
monopile installation completion, SouthCoast anticipates it would then 
take approximately 4 hours to move to the next piling location. Once at 
the new location, a 1-hour marine mammal monitoring period would occur 
such that there would be a minimum of 5 hours between pile 
installations. Based on this schedule, SouthCoast estimates a maximum 
of two monopiles could be sequentially driven per day using a single 
installation vessel, assuming a 24-hour pile driving schedule.
    For Project 1 Scenario 1, it is assumed that all 71 WTG monopiles 
would be installed using only an impact hammer (i.e., no vibratory pile 
driving), requiring a maximum of 284 hours (71 WTGs x 4 hours each) of 
active impact pile driving. Similarly, for Project 2 Scenario 1, it is 
assumed that all 68 monopiles would be installed using the same 
approach, for a total of 272 hours of impact hammering. However, for 
Project 2 Scenario 2, it is assumed that 67 (out of a total of 73) 
monopiles would be installed using a combination of vibratory and 
impact pile driving, and 6 monopiles would be installed using only 
impact pile driving. Installation of all WTG foundations for Project 2 
Scenario 2 would require a total of approximately 212 hours (6 WTGs x 4 
hours plus 67 WTGs x 2.8 hours each) of impact and 23 hours (67 WTGs x 
20 minutes each) of vibratory pile driving.

Pin-Piled Jacket

    As an alternative to monopiles, SouthCoast proposed one scenario 
for each Project (P1S2 and P2S3) that, when combined, would include 
installation of 147 pin-piled jacket foundations to support WTGs. 
Jackets are large lattice structures made of steel tubes welded 
together and supported by securing piles (i.e., pin piles). Figure 4 of 
SouthCoast's application provides a conceptual example of this type of 
foundation. For the SouthCoast Project, each WTG piled jacket 
foundation would have up to four legs supported by one pin pile per 
leg, for a total of up to 588 pin piles to support 147 WTGs. Each pin 
pile would have a maximum diameter of 4.5 m (14.7 ft). Pin-piled jacket 
foundation installation is a multi-stage process, beginning with 
preparation of the seabed by clearing any debris. The WTG jacket 
foundations are expected to be pre-piled, meaning that pin piles would 
be installed first, and the jacket structure would be set on those pre-
installed piles. Once the piled-jacket foundation materials are 
delivered to the Lease Area, a reusable template would be placed on the 
prepared seabed to ensure accurate positioning of the pin piles that 
will be installed to support the jacket. Pin piles would be 
individually lowered into the template and driven to the target 
penetration depth using the same approach described for monopile 
installation. For installations requiring only impact pile driving 
(e.g., P1S2), SouthCoast would install pin piles using an impact pile 
driver with a maximum hammer energy of 3,500 kJ (MHU 3500S) for a total 
of 4,000 strikes (including soft-start hammer strikes) at a rate of 30 
strikes per minute to a maximum penetration depth of 70 m (229.6 ft). 
When installations require both types of pile driving, this impact pile 
driving sequence would only begin after SouthCoast utilized a vibratory 
hammer (S-CV640) to set the pile to a depth providing adequate 
stability. Subsequent impact hammering (using the same hammer 
specified) above would require fewer strikes (n=2,667) to drive the 
pile to the final 70-m maximum penetration depth.
    Under typical conditions, impact-only installation (applicable to 
P1S2, and all OSP pin-piled jacket foundations) of each pin pile is 
estimated to require approximately 2 hours of active impact pile 
driving (4,000 strikes/30 strikes per minute equals approximately 133 
minutes, or 2.2 hours), for a maximum of 8.8 hours total for a single 
WTG or OSP pin- piled jacket foundation supported by 4 pin piles. For 
each pin pile requiring vibratory and impact pile driving (applicable 
to P2S3 WTG pin-piled jacket foundations only), the installation would 
begin with 90 minutes of vibratory hammering per pin pile, and would 
require fewer hammer strikes per pile over a shorter duration compared 
to impact-only installations (2,667 strikes/30 strikes per minute 
equals approximately 89 minutes, or 1.5 hours), for a total of 6 hours 
for each installation method (12 hours total). Pile driving would occur 
continuously or intermittently, with installations requiring both 
methods of pile driving punctuated by the time required to change from 
the vibratory to impact hammer. SouthCoast estimates that they could 
install a maximum of four pin piles per day, assuming use of a single 
installation vessel and 24-hour pile driving operations. Following pin 
pile installations, a vessel would install the jacket to the piles, 
either directly after the piling vessel completes operations or up to 
one year later.
    For Project 1 Scenario 2, it is assumed that all 85 WTG pin-piled 
jacket foundations (for a total of 340 pin piles) would be installed 
using only an impact hammer (i.e., no vibratory pile driving), 
requiring a maximum of 680 hours (85 WTGs x 8 hours each) of active 
impact pile driving. For Project 2 Scenario 3, it is assumed that 48 
(out of a total of 62) pin-piled jacket foundations (or 192 out of 248 
pin piles) would be installed using a combination of vibratory and 
impact pile driving, and 14 pin-piled jacket foundations (or 56 pin 
piles) would be installed using only impact pile driving. Installation 
of all WTG foundations for Project 2 Scenario 3 would require a total 
of approximately 184 hours (14 WTGs x 8 hours plus 48 WTGs x 1.5 hours 
each) of impact and 72 hours (48 WTGs x 90 minutes (or 1.5 hours) each) 
of vibratory pile driving.
    Installation of WTG monopile and pin-piled jacket foundations is

[[Page 53720]]

anticipated to result in take of marine mammals due to noise generated 
during pile driving. Therefore, SouthCoast has requested, and NMFS 
proposes to authorize, take by Level A harassment and Level B 
harassment of marine mammals incidental to this activity.

Suction Bucket

    Suction bucket jackets have a similar steel lattice design to the 
piled jacket described previously, but the connection to the seafloor 
is different (see Figure 5 in SouthCoast's application for a conceptual 
example of the WTG suction bucket jacket foundation). These 
substructures use suction-bucket foundations instead of piles to secure 
the structure to the seabed; thus, no impact driving would be used for 
installation of WTG suction bucket jackets. Should SouthCoast select 
this foundation type for Project 2, each of the suction-bucket jacket 
substructures, including four buckets per foundation (one per leg), 
would be installed as described below. Similar to monopiles and pin-
piled jackets, the number of suction-bucket jacket foundations will 
depend on the final design for Project 1. For suction-bucket jackets, 
the jacket is lowered to the seabed, the open bottom of the bucket and 
weight of the jacket embeds the bottom of the bucket in the seabed. To 
complete the installation and secure the foundation, water and air are 
pumped out of the bucket creating a negative pressure within the 
bucket, which embeds the foundation buckets into the seabed. The jacket 
can also be leveled at this stage by varying the applied pressure. The 
pumps will be released from the suction buckets once the jacket reaches 
its designed penetration. The connection of the required suction hoses 
is typically completed using a remotely operated vehicle (ROV).
    As previously indicated, installation of suction bucket foundations 
is not expected to result in take of marine mammals; thus, this 
activity is not further discussed.

Offshore Substation Platform (OSP)

    Each construction scenario SouthCoast defined includes installation 
of a pin-piled jacket foundation to support a single OSP per Projects 1 
and 2, However, in the ITA application, SouthCoast indicates that their 
project design envelope includes the potential installation of up to a 
total of 5 OSPs, situated on the same 1 nm x 1 nm (1.9 km x 1.9 km) 
grid layout as the WTG foundation, and describes three OSP designs 
(i.e., modular, integrated, or Direct Current (DC) Converter) that are 
under consideration (see Figures 6, 7, and 8 in SouthCoast's ITA 
application). The number of OSPs installed would vary based upon 
design. Based on the COP PDE, SouthCoast could install a minimum of a 
single modular OSP on a monopile foundation, and a maximum of five DC 
Converter OSPs, each with nine pin-piled jacket foundations secured by 
three pin piles each, for a total of 135 pin piles. All OSP monopile 
and pin-piled jacket foundations would be installed using only impact 
pile driving.
    Installation of an OSP monopile foundation would follow the same 
parameters (e.g., pile diameter, hammer energy, penetration depth) and 
procedure as previously described for WTG monopiles. OSP piled jacket 
foundations would be similar to that described for WTG piled jacket 
foundations but would be installed using a post-piling, rather than 
pre-piling, installation sequence. In this sequence, the seabed is 
prepared, the jacket is set on the seafloor, and the piles are driven 
through the jacket legs to the designed penetration depth (dependent 
upon which OSP design is selected). The piles are connected to the 
jacket via grouted and/or swaged connections. A second vessel may 
perform grouting tasks, freeing the installation vessel to continue 
jacket installation at a subsequent OSP location, if needed. Pin piles 
for each jacket design would be installed using an impact hammer with a 
maximum energy of 3,500 kJ. A maximum of four OSP pin piles could be 
installed per day using a single vessel, assuming 24-hour pile driving 
operations. All impact pile driving activity of pin piles would include 
a 20-minute soft-start at the beginning of each pile installation. 
Installation of a single OSP piled jacket foundation by impact pile 
driving (the only proposed method) would vary by design and the 
associated number of supporting pin piles, each of which would require 
2 hours of impact hammering.
    The ``Modular OSP'' design would sit on any one of the three types 
of substructure designs (i.e., monopile, piled jacket, or suction 
bucket) similar in size and weight to those described for the WTGs (see 
Section 1.1.1 in SouthCoast's ITA application), with the topside 
connected to a transition piece (TP). This Modular OSP design is an AC 
solution and will likely hold a single transformer with a single export 
cable. This option is a relatively small design relative to other 
options and, thus, has benefits related to manufacture, transportation, 
and installation. An example of the Modular OSP on a jacket 
substructure is shown in Figure 6 of SouthCoast's ITR application. The 
Modular OSP design assumes an OSP topside height ranging from 50 m (164 
ft) to 73.9 m (242.5 ft). A Modular OSP piled jacket foundation would 
be the smallest and include three to four legs with one to two pin 
piles per leg (three to eight total pin piles per piled jacket). Pin 
piles would have a diameter of up to 4.5 m (14.7 ft) and would be 
installed using up to a 3,500-kJ hammer to a target penetration depth 
of 70 m (229.6 ft) below the seabed.
    The ``Integrated OSP'' design would have a jacket substructure and 
a larger topside than the Modular OSP. This OSP option is also an AC 
solution and is designed to support a high number of inter-array cable 
connections as well as the connection of multiple export cables. This 
design differs from the Modular OSP in that it is expected to contain 
multiple transformers and export cables integrated into a single 
topside. The Integrated OSP design assumes the same topside height 
indicated for the Modular design. Depending on the final weight of the 
topside and soil conditions, the jacket substructure may be four- or 
six-legged and require support from one to three piles per leg (up to 
16 pin piles). The larger size of the Integrated OSP would provide 
housing for a greater number of electrical components as compared to 
smaller designs (such as the Modular OSP), reducing the number of OSPs 
required to support the proposed Project. An example of the integrated 
OSP design is shown in Figure 7 of SouthCoast's ITR application.
    SouthCoast may install one or more ``DC Converter OSPs.'' This OSP 
option would serve as a gathering platform for inter-array cables and 
then convert power from high-voltage AC to high-voltage DC or it could 
be connected to one or more AC gathering units (Modular or Integrated 
OSPs) and serve to convert power from AC to DC prior to transmission on 
an export cable. The DC Converter OSP would be installed on a piled 
jacket foundation with four legs, each supported by three to four 3.9-m 
(12.8-ft) pin piles per leg (up to 16 total pin piles per jacket), 
installed using a 3,500-kJ hammer to a target penetration depth of 90 m 
(295.3 ft) below the seabed. Please see Figure 8 in SouthCoast's ITR 
application for example of a DC jacket OSP design. Although SouthCoast 
has not yet selected an OSP design or finalized their foundation 
installation plan, they anticipate that they would only install only 
two of the five OSPs included in the PDE, one per Project. Each OSP 
would be supported by a piled jacket foundation with four legs anchored 
by

[[Page 53721]]

three to four pin piles (for a total of up to 16 pin piles per OSP 
piled jacket). SouthCoast plans to install a maximum of four OSP jacket 
pin piles per day, so an OSP jacket foundation requiring 16 pin piles 
would be installed over four days (intermittently). For all three OSP 
piled jacket options (modular, integrated and DC-converter), 
installation of a single pin pile is anticipated to take up to 2 hours 
of pile driving. It is anticipated that a maximum of eight pin piles 
could be driven into the seabed per day assuming 24-hour pile driving 
operation. Pile driving activity will include a soft-start at the 
beginning of each pin pile installation. Impacts of pile-driving noise 
incidental to OSP piled jacket foundation installation have been 
evaluated based on the use of a 3,500 kJ hammer, as this is 
representative of the maximum hammer energy included in the PDE.
    Installation of OSP foundations is anticipated to result in take of 
marine mammals due to noise generated during pile driving. Therefore, 
SouthCoast has requested, and NMFS proposes to authorize, take by Level 
A harassment and Level B harassment of marine mammals incidental to OSP 
foundation installation.
HRG Surveys
    SouthCoast would conduct HRG surveys to identify any seabed debris 
and to support micrositing of the WTG and OSP foundations and ECCs. 
These surveys may utilize active acoustic equipment such as multibeam 
echosounders, side scan sonars, shallow penetration sub-bottom 
profilers (SBPs) (e.g., parametric Compressed High-Intensity Radiated 
Pulses (CHIRP) SBPs and non-parametric SBP), medium penetration sub-
bottom profilers (e.g., sparkers and boomers), and ultra-short baseline 
positioning equipment, some of which are expected to result in the take 
of marine mammals. Surveys would occur annually, with durations 
dependent on the activities occurring in that year (i.e., construction 
years versus non-construction years).
    HRG surveys will be conducted using up to four vessels. On average, 
80-line km (49.7-mi) will be surveyed per vessel each survey day at 
approximately 5.6 km/hour (3 knots) on a 24-hour basis although some 
vessels may only operate during daylight hours (~12-hour survey 
vessels).
    During the 2-year construction phase, an estimated 4,000 km (2,485 
mi) may be surveyed within the Lease Area and 5,000 km (3,106 mi) along 
the ECCs in water depth ranging from 2 m (6.5 ft) to 62 m (204 ft). A 
maximum of four vessels will be used concurrently for surveying. While 
the final survey plans will not be completed until construction 
contracting commences, HRG surveys are anticipated to operate at any 
time of year for a maximum of 112.5 survey days per year.
    During non-construction periods (3 of the 5 years within the 
effective period of the regulations), SouthCoast would survey an 
estimated 2,800 km (1,7398 mi) in the Lease Area and 3,200 km (1,988.4 
mi) along the ECCs each year for three years (n=18,000 km total). Using 
the same estimate of 80 km (49.7 mi) of surveys completed each day per 
vessel, approximately 75 days of surveys would occur each year, for a 
total of up to 225 active sound source days over the 3-year operations 
period.
    Of the HRG equipment types proposed for use, the following sources 
have the potential to result in take of marine mammals:
     Shallow penetration sub-bottom profilers (SBPs) to map the 
near-surface stratigraphy (top 0 to 5 m (0 to 16 ft) of sediment below 
seabed). A CHIRP system emits sonar pulses that increase in frequency 
over time. The pulse length frequency range can be adjusted to meet 
Projectvariables. These are typically mounted on the hull of the vessel 
or from a side pole.
     Medium penetration SBPs (boomers) to map deeper subsurface 
stratigraphy as needed. A boomer is a broad-band sound source operating 
in the 3.5 Hz to 10 kHz frequency range. This system is typically 
mounted on a sled and towed behind the vessel.
     Medium penetration SBPs (sparkers) to map deeper 
subsurface stratigraphy as needed. A sparker creates acoustic pulses 
from 50 Hz to 4 kHz omni-directionally from the source that can 
penetrate several hundred meters into the seafloor. These are typically 
towed behind the vessel with adjacent hydrophone arrays to receive the 
return signals.
    Table 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 is likely 
to be detected by marine mammals given the source level, frequency, and 
beamwidth of the equipment. Equipment with operating frequencies above 
180 kHz (e.g., SSS, MBES) and equipment that does not have an acoustic 
output (e.g., magnetometers) will also be used but are not discussed 
further because they are outside the general hearing range of marine 
mammals likely to occur in the Lease Area and ECCs. No take is expected 
from the operation of these sources; therefore, they are not discussed 
further.

                                    Table 3--Summary of Representative HRG Survey Equipment and Operating Parameters
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                  Source
                               Representative     Operating       Level        Source       Pulse       Repetition       Beamwidth
       Equipment type              model          frequency    SPLrms (dB)   Level0-pk     duration      rate (Hz)       (degrees)    Information source
                                                    (kHz)                       (dB)         (ms)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sub-bottom Profiler.........  EdgeTech 3100              2-16          179          184           10             9.1              51  CF.
                               with SB 2-16               1-6          176          183         14.4              10              66  CF.
                               \1\ towfish.
                              EdgeTech DW-106
                               \1\.
                              Knudson Pinger               15          180          187            4               2              71  CF.
                               \2\.                       2-7          199          204           10            14.4              82  CF.
                              Teledyn Benthos
                               CHIRP III--TTV
                               170 \3\.
Sparker \4\.................  Applied                0.01-1.9          203          213          3.4               2            Omni  CF.
                               Acoustics Dura-
                               Spark UHD (400
                               tips, 800 J).
                              Geomarine Geo-         0.01-1.9          203          213          3.4               2            Omni  CF.
                               Spark (400
                               tips, 800 J).
Boomer......................  Applied                   0.1-5          205          211          0.9               3              61  CF.
                               Acoustics
                               triple plate S-
                               Boom (700-
                               1,000 J).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: J = joule; kHz = kilohertz; dB = decibels; SL = source level; UHD = ultra-high definition; rms = root-mean square; [mu]Pa = microPascals; re =
  referenced to; SPL = sound pressure level; PK = zero-to-peak pressure level; Omni = omnidirectional source; CF = Crocker and Fratantonio (2016).
\1\ The EdgeTech Chirp 512i measurements and specifications provided by Crocker and Fratantonio (2016) were used as a proxy for the Edgetech 3100 with
  SB-216 towfish and EdgeTech DW-106.

[[Page 53722]]

 
\2\ The EdgeTech Chirp 424 as a proxy for source levels as the Chirp 424 has similar operation settings as the Knudsen Pinger SBP.
\3\ The Knudsen 3202 Echosounder measurements and specifications provided by Crocker and Fratantonio (2016) were used as a proxy for the Teledyne
  Benthos Chirp III TTV 170.
\4\ The SIG ELC 820 Sparker, 5 m source depth, 750 J setting was used a proxy for both the Applied Acoustics Dura-Spark UHD (400 tips, 800 J) and
  Geomarine Geo-Spark (400 tips, 800 J).

    Based on the operating frequencies of HRG survey equipment in table 
3 and the hearing ranges of the marine mammals that have the potential 
to occur in the Lease Area and ECCs, HRG survey activities have the 
potential to result in take by Level B harassment of marine mammals. No 
take by Level A harassment is anticipated as a result of HRG survey 
activities.
UXO/MEC Detonations
    SouthCoast anticipates encountering UXO/MECs during Project 
construction in the Lease Area and along the ECCs. 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. SouthCoast plans to remove any UXO/MEC encountered, 
else, the risk of incidental detonation associated with conducting 
seabed-altering activities, such as cable laying and foundation 
installation in proximity to UXO/MECs, would potentially jeopardize the 
health and safety of Projectparticipants.
    SouthCoast would follow an industry standard As Low as Reasonably 
Practicable (ALARP) process that minimizes the number of detonations, 
to the extent possible. For UXO/MECs that are positively identified in 
proximity to specified activities on the seabed, several alternative 
strategies would be considered prior to in-situ UXO/MEC disposal. These 
may include: (1) relocating the activity away from the UXO/MEC 
(avoidance); (2) 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.
    SouthCoast is currently conducting a study to more accurately 
determine the number of UXO/MECs that may be encountered during the 
specified activities (see section 1.1.5 in SouthCoast's ITA 
application). Based on estimates for other offshore wind projects in 
southern New England, SouthCoast assumes that up to ten UXO/MEC 454-kg 
(1000 pounds; lbs) charges, which is the largest charge that is 
reasonably expected to be encountered, may require in situ detonation. 
Although it is highly unlikely that all ten charges would weigh 454 kg, 
this approach was determined to be the most conservative for the 
purposes of impact analysis. All charged detonations would occur on 
different days (i.e., only one detonation would occur per day). In the 
event that high-order detonation is determined to be the preferred and 
safest method of disposal, all detonations would occur during daylight 
hours. SouthCoast proposed a seasonal restriction on UXO/MEC 
detonations from December 1-April 30, annually.
    UXO/MEC activities have the potential to result in take by Level A 
harassment and Level B harassment of marine mammals. No non-auditory 
take by Level A harassment is anticipated due to proposed mitigation 
and monitoring measures.
Cable Landfall Construction
    Installation of the SouthCoast export cables at the designated 
landfall sites will be accomplished using horizontal directional 
drilling (HDD) methodology. HDD is a ``trenchless'' process for 
installing cables or pipes which enables the cables to remain buried 
below the beach and intertidal zone while limiting environmental impact 
during installation. Drilling activities would occur on land with the 
borehole extending under the seabed to an exit point offshore, outside 
of the intertidal zone. There will be up to two ECCs, both exiting the 
Lease Area in the northwestern corner. These then split, with one 
making landfall at Brayton Point in Somerset, MA (Brayton Point ECC) 
and the other in Falmouth, MA (Falmouth ECC). The Brayton Point ECC is 
anticipated to contain up to six export cables, bundled where 
practicable, while the Falmouth ECC is anticipated to contain up to 
five export cables. HDD seaward exit points will be sited within the 
defined ECCs at the Brayton Point and intermediate Aquidneck Island 
landfall sites and at the Falmouth landfall site(s). The exit points 
will be within approximately 3,500 ft (1,069 m) of the shoreline for 
the Falmouth ECC landfall(s), and within approximately 1,000 ft (305 m) 
of the shoreline for the Brayton Point landfalls.
    At the seaward exit point, construction activities may include 
installation of either a temporary gravity-based structure (i.e., 
gravity cell or gravity-based cofferdam) or a dredged exit pit, neither 
of which would require pile driving or hammering. Additionally, a 
conductor pipe may be installed at the exit point to support the 
drilling activity. Conductor pipe installation would include pushing or 
jetting rather than pipe ramming.
    For the Falmouth landfall locations, the proposed HDD trajectory is 
anticipated to be approximately 0.9 mi (1.5 km) in length with a cable 
burial depth of up to approximately 90 ft (27.4 m) below the seabed. 
HDD boreholes will be separated by a distance of approximately 33 ft 
(10 m). Each offshore export cable is planned to require a separate 
HDD, with an individual bore and conduit for each export cable. The 
number of boreholes per site will be equal to the number of power 
cables installed. The Falmouth ECC would include up to four power 
cables with up to four boreholes at each landfall site. There may be up 
to one additional communications cable; however, the communications 
cable would be installed within the same bore as one of the power 
cables, likely within a separate conduit.
    For the Brayton Point and Aquidneck Island intermediate landfall 
locations, the proposed HDD trajectory is anticipated to be 
approximately 0.3 mi (0.5 km) in length with a cable burial depth of up 
to approximately 90 ft (27.4 m) below the seabed. HDD bores will be 
separated by a distance of approximately 33 ft (10 m). It is 
anticipated the high-voltage DC cables will be unbundled at landfall. 
Each high-voltage DC power cable is planned to require a separate HDD, 
with an individual bore and conduit for each power cable. The Brayton 
Point and Aquidneck Island ECCs will include up to four power cables 
for a total of up to four boreholes at each landfall site. Each 
dedicated communications cable may be installed within the same bore as 
a power cable, likely within a separate conduit.
    In collaboration with the HDD contractor, SouthCoast will further 
assess the potential use of a dredged exit

[[Page 53723]]

pit and/or gravity cell at each landfall location. The specifics of 
each site will be evaluated in detail, in terms of soil and metocean 
conditions (i.e., current), suitability for maintaining a dredged exit 
pit for the duration of the HDD construction, and other construction 
planning factors that may affect the HDD operation.
    The relatively low noise levels generated by installation and 
removal of gravity-cell cofferdams, dredged exit pits, and conductor 
pipe are not expected to result in Level A harassment or Level B 
harassment of marine mammals. SouthCoast is not requesting, and NMFS is 
not proposing to authorize, take associated with landfall construction 
activities. Therefore, these activities are not analyzed further in 
this document.
Cable Laying and Installation
    Cable burial operations would occur both in the Lease Area for the 
inter-array cables connecting WTGs to OSPs and in the ECCs for cables 
carrying power from the OSPs to shore. The offshore export cables would 
be buried in the seabed at a target depth of up to 1.0 to 4.0 m (3.2 to 
13.1 ft) while the inter-array cables would be buried at a target depth 
up to 1.0 to 2.5 m (3.2 to 8.2 ft). Both cable types would be buried 
onshore up to the transition joint bays. All cable burial operations 
would follow installation of the monopile foundations as the 
foundations must be in place to provide connection points for the 
export cable and inter-array cables. Cable laying, cable installation, 
and cable burial activities planned to occur during the construction of 
the SouthCoast Project May include the following: jetting; vertical 
injection; leveling; mechanical cutting; plowing (with or without jet-
assistance); pre-trenching; boulder removal; and controlled flow 
excavation. Installation of any required protection at the cable ends 
is typically completed prior to cable installation from the vessel.
    Some dredging may be required prior to cable laying due to the 
presence of sandwaves. Sandwave clearance may be undertaken to provide 
a level bottom to install the export cable. The work could be 
undertaken by traditional dredging methods such as a trailing suction 
hopper. Alternatively, controlled flow excavation or a water-injection 
dredger could be used. In some cases, multiple passes may be required. 
The method of sand wave clearance SouthCoast chooses would be based on 
the results from the site investigation surveys and cable design.
    As the noise levels generated from cable laying and installation 
work are low, the potential for take of marine mammals to result is 
discountable. SouthCoast 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.
Vessel Operation
    SouthCoast will utilize various types of vessels over the course of 
the 5-year proposed regulations for surveying, foundation installation, 
cable installation, WTG and OSP installation, UXO/MEC detonation, and 
support activities. SouthCoast anticipates operating an average of 15 
to 35 vessels daily depending on construction phase, with an expected 
maximum of 50 vessels in the Lease Area at one time during the 
foundation installation period. Table 4 provides a list of the vessel 
types, number of each vessel type, number of expected trips, and 
anticipated years each vessel type will be in use. All vessels will 
follow the vessel strike avoidance measures as described in the 
Proposed Mitigation section.
    To support offshore construction, assembly and fabrication, crew 
transfer and logistics, as well as other operational activities, 
SouthCoast has identified several existing domestic port facilities 
located in Massachusetts (Ports of Salem, New Bedford, Fall River), 
Rhode Island (Ports of Providence and Davisville), Connecticut (Port of 
New London), and to a lesser extent Maryland (Sparrows Point Port), 
South Carolina (Port of Charleston), and Texas (Port of Corpus Cristi).
    The largest vessels are expected to be used during the foundation 
installation phase with heavy transport vessels, heavy lift crane 
vessels, cable laying vessels, supply and crew vessels, and associated 
tugs and barges transporting construction equipment and materials. A 
large service operation vessel would have the ability to stay in the 
lease area and house crews overnight. These larger vessels will 
generally move slowly over a short distance between work locations, 
within the Lease Area and along ECCs. Smaller vessels would be used to 
transfer crew and smaller dimension Project materials to and from, as 
well as within, the Lease Area. Transport vessels will travel between 
several ports and the Lease Area over the course of the construction 
period following mandatory vessel speed restrictions (see Proposed 
Mitigation section). These vessels will range in size from smaller crew 
transport to tug and barge vessels. Construction crews responsible for 
assembling the WTGs would hotel onboard installation vessels at sea, 
thus limiting the number of crew vessel transits expected during the 
construction period. WTG and OSP foundation installation vessels may 
include jack-up, DP, or semi-submersible vessels. Jack-up vessels lower 
their legs into the seabed for stability and then lift out of the 
water, whereas DP vessels utilize computer-controlled positioning 
systems and thrusters to maintain their station. SouthCoast is also 
considering the use of heavy lift vessels, barges, feeder vessels, and 
roll-on lift-off vessels to transport WTG components to the Lease Area 
for installation by the WTG installation vessel. Fabrication and 
installation vessels may include transport vessels, feeder vessels, 
jack-up vessels, and installation vessels.
    Sounds from vessels associated with the proposed Project are 
anticipated to be similar in frequency to existing levels of commercial 
traffic present in the region. Vessel sound would be associated with 
cable installation vessels and operations, piling installation vessels, 
and general transit to and from WTG or OSP locations during 
construction. During construction, it is estimated that multiple 
vessels may operate concurrently at different locations throughout the 
Lease Area or ECCs. Some of these vessels may maintain their position 
(using DP thrusters) during pile driving or other construction 
activities. The dominant underwater sound source on DP vessels arises 
from cavitation on the propeller blades of the thrusters (Leggat et 
al., 1981). The noise power from the propellers is proportional to the 
number of blades, propeller diameter, and propeller tip speed. Sound 
levels generated by vessels using DP are dependent on the operational 
state and weather conditions.
    All vessels emit sound from propulsion systems while in transit. 
The SouthCoast Project would be constructed in an area that 
consistently experiences extensive marine traffic. As such, marine 
mammals in the general region are regularly subjected to vessel 
activity and would potentially be habituated to the associated 
underwater noise as a result of this exposure (BOEM, 2014b). Because 
noise from vessel traffic associated with construction activities is 
likely to be similar to background vessel traffic noise, the potential 
risk of impacts from vessel noise to marine life is expected to be low 
relative to the risk of impact from pile-driving sound.
    Sound produced through use of DP thrusters is considered a 
continuous sound source and similar to that

[[Page 53724]]

produced by transiting vessels. DP thrusters are typically operated 
either in a similarly predictable manner or used intermittently for 
short durations around stationary activities. Sound produced by DP 
thrusters would be preceded by and associated with sound from ongoing 
vessel noise and would be similar in nature. Any marine mammals in the 
vicinity of the activity would be aware of the vessel's presence, thus 
making it unlikely that the noise source would elicit a startle 
response. Construction-related vessel activity, including the use of 
dynamic positioning thrusters, is not expected to result in take of 
marine mammals. SouthCoast did not request, and NMFS does not propose 
to authorize, take associated with vessel activity.
    During operations, SouthCoast will use crew transfer vessels (CTVs) 
and service operations vessels (SOVs). The number of each vessel type, 
number of trips, and potential ports to be used during operations and 
maintenance are provided in table 4. The operations vessels will follow 
the vessel strike avoidance measures as described in the Proposed 
Mitigation section.

               Table 4--Type and Number of Vessels Anticipated During Construction and Operations
----------------------------------------------------------------------------------------------------------------
                                                                 Supply trips
                                                                 to port from
                                                   Estimated    lease area (or
                 Vessel types                      number of    point of entry      Anticipated years in use
                                                  vessel type   in U.S., where
                                                                  applicable
                                                                     \1\)
----------------------------------------------------------------------------------------------------------------
                                         Vessel Use During Construction
----------------------------------------------------------------------------------------------------------------
Heavy Lift Crane Vessel.......................             1-5              70  2028-2031 (P1 and 2).
Heavy Transport Vessel........................            1-20              65  2027-2031 (P1 and 2).
Tugboat.......................................            1-12             655  2028-2031 (P1 and 2).
Crew Transfer Vessel..........................             2-5           1,608  2028-2031 (P1 and 2).
Anchor Handling Tug...........................            1-10              16  2028-2031 (Projects 1 and 2).
Scour Protection Installation Vessel..........             1-2              40  2028-2030 (P1 and P2).
Cable Laying Barge............................             1-3              20  2027-2028 (Project 1).
                                                                                2029-2030 (Project 2).
Cable Transport and Lay Vessel................             1-5              88  2028-2029 Project 1 and Project
                                                                                 2.
Maintenance Crew/CTVs.........................             2-5           1,608  2028-2031 (P1 and 2).
Dredging Vessel...............................             1-5             100  2026-2027 (P1) 2029-2030 (P2).
Survey Vessel.................................             1-5              26  2027-2031 (P1 and P2).
Barge.........................................             1-6             510  2028-2031 (P1 and P2).
Jack-up Accommodation Vessel..................             1-2              14  2029-2030 (P1 and P2).
DP Accommodation Vessel.......................             1-2              16  2029-2030 (P1 and P2).
Service Operation Vessel......................             1-4             480  2029-2031 (P1 and P2).
Multi-purpose Support Vessel/Service Operation             1-8             660  2027-2031 (P1 and P2).
 Vessel.
----------------------------------------------------------------------------------------------------------------
                                          Vessel Use During Operations
----------------------------------------------------------------------------------------------------------------
Maintenance Crew/Crew Transfer Vessels (CTVs).             1-2          15,015  2028-2031.
Service Operation Vessel......................             1-2           1,638
----------------------------------------------------------------------------------------------------------------

    While vessel strikes cause injury or mortality of marine mammals, 
NMFS does not anticipate such taking to occur from the specified 
activity due to general low probability and proposed extensive vessel 
strike avoidance measures (see Proposed Mitigation section). SouthCoast 
has not requested, and NMFS is not proposing to authorize, take from 
vessel strikes.
Seabed Preparation
    Seabed preparations will be the first offshore activity to occur 
during the construction phase of the SouthCoast Project, and may 
include scour (i.e., erosion) protection, sand leveling, sand wave 
removal, and boulder removal. Scour protection is the placement of 
materials on the seafloor around the substructures to prevent the 
development of scour, or erosion, created by the presence of 
structures. Each substructure used for WTGs and OSPs may require 
individual scour protection, thus the type and amount utilized will 
vary depending on the final substructure type selected for 
installation. For a substructure that utilizes seabed penetration in 
the form of piles or suction caissons, the use of scour protectant to 
prevent scour development results in minimized substructure 
penetration. Scour protection considered for Projects 1 and 2 may 
include rock (rock bags), concrete mattresses, sandbags, artificial 
seaweeds/reefs/frond mats, or self-deploying umbrella systems 
(typically used for suction-bucket jackets). Installation activities 
and order of events of scour protection will depend on the type and 
material used. For rock scour protection, a rock placement vessel may 
be deployed. A thin layer of filter stones would be placed prior to 
pile driving activity while the armor rock layer would be installed 
following completion of foundation installation. Frond mats or 
umbrella-based structures may be pre-attached to the substructure, in 
which case the pile and scour protection would be installed 
simultaneously. For all types of scour protection materials considered, 
the results of detailed geological campaigns and assessments will 
support the final decision of the extent of scour protection required. 
Placement of scour protection may result in suspended sediments and a 
minor conversion of marine mammal prey benthic habitat conversion of 
the existing sandy bottom habitat to a hard bottom habitat as well as 
potential beneficial reef effects (see Section 1.3 of the ITA 
application).
    Seabed preparation may also include leveling, sand wave removal, 
and boulder removal. SouthCoast may utilize equipment to level the 
seabed locally in order to use seabed operated cable burial tools to 
ensure consistent

[[Page 53725]]

burial is achieved. If sand waves are present, the tops may be removed 
to provide a level bottom to install the export cable. Sand wave 
removal may be conducted using a trailing suction hopper dredger (or 
similar), a water injection dredge in shallow areas, or a constant flow 
excavator. Any boulder discovered in the cable route during pre-
installation surveys that cannot be easily avoided by micro-routing may 
be removed using non-explosive methods such as a grab lift or plow. If 
deemed necessary, a pre-lay grapnel run will be conducted to clear the 
cable route of buried hazards along the installation route to remove 
obstacles that could impact cable installation such as abandoned 
mooring lines, wires, or fishing equipment. Site-specific conditions 
will be assessed prior to any boulder removal to ensure that boulder 
removal can safely proceed. Boulder clearance is a discreet action 
occurring over a short duration resulting in short term direct effects.
    Sound produced by Dynamic Positioning (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 a pull vessel with 
a towed plow or a support vessel carrying a boulder grab would be 
comparable to or less than the noise produced by DP vessels, so impacts 
are also expected to be similar. Boulder clearance is a discreet action 
occurring over a short duration resulting in short term direct effects. 
Additionally, sound produced by boulder clearance vessels and equipment 
would be preceded by, and associated with, sound from ongoing vessel 
noise and would be similar in nature. presence, further reducing the 
potential for startle or flight responses on the part of marine 
mammals. Monitoring of past projects that entailed use of DP thrusters 
has shown a lack of observed marine mammal responses as a result of 
exposure to sound from DP thrusters (NMFS 2018). As DP thrusters are 
not expected to result in take of marine mammals, these activities are 
not analyzed further in this document.
    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 SouthCoast 
did not request, and NMFS does not propose to authorize, any takes 
associated with seafloor preparation work. These activities are not 
analyzed further in this document.
    NMFS does not expect site preparation work, including boulder 
removal and sand leveling, 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 non-impulsive 
sound produced by the DP cable lay vessels used to install inter-array 
cables in the Lease Area and export cables along the ECCs. Boulder 
clearance is a discreet action occurring over a short duration 
resulting in short term direct effects.
    Southcoast did not request take of marine mammals incidental to 
this activity, and based on the activity, NMFS neither expects nor 
proposes to authorize take of marine mammals incidental to this 
activity. Thus, this activity will not be discussed further.
Fisheries and Benthic Monitoring
    SouthCoast has developed a fisheries monitoring plan (FMP) focusing 
on the Lease Area, an inshore FMP that focuses on nearshore portions of 
the Brayton Point ECC (i.e., the Sakonnet River), and a benthic 
monitoring plan that covers both offshore and inshore portions of the 
Lease Area and ECCs. The fisheries and benthic monitoring plans for the 
SouthCoast Project were developed following guidance outlined in 
``Guidelines for Providing Information on Fisheries for Renewable 
Energy Development on the Atlantic Outer Continental Shelf'' (BOEM, 
2019) and the Responsible Offshore Science Alliance (ROSA) ``Offshore 
Wind Project Monitoring Framework and Guidelines'' (2021).
    SouthCoast is working with the University of Massachusetts 
Dartmouth's School for Marine Science and Technology (SMAST) (in 
partnership with the Massachusetts Lobstermen's Association) and 
Inspire Environmental to develop and conduct surveys as a cooperative 
research program using local fishing vessels and knowledge. SouthCoast 
intends to conduct their research on contracted commercial and 
recreational fishing vessels whenever practicable.
    Offshore fisheries monitoring will likely include the following 
types of surveys: trawls, ventless trap, drop camera, neuston net, and 
acoustic telemetry with tagging of highly migratory species (e.g., blue 
sharks). Inshore fisheries monitoring surveys will also include 
acoustic telemetry targeting commercially and recreationally important 
fish species (e.g., striped bass) and trap survey targeting whelk. 
Benthic monitoring plans are under development and may include grab 
samples and collection of imagery. Because the gear types and equipment 
used for the acoustic telemetry study, benthic habitat monitoring, and 
drop camera monitoring surveys do not have components with which marine 
mammals are likely to interact (i.e., become entangled in or hooked 
by), these activities are unlikely to have any impacts on marine 
mammals. Therefore, only trap and trawl surveys, in general, have the 
potential to result in harassment to marine mammals. However, based on 
proposed mitigation and monitoring measures, taking marine mammals from 
this specified activity is not anticipated. A full description of 
mitigation and monitoring measures can be found in the Proposed 
Mitigation and Proposed Monitoring sections.
    Given the planned implementation of the mitigation and monitoring 
measures, SouthCoast did not request, and NMFS is not proposing to 
authorize, take of marine mammals incidental to research trap and trawl 
surveys. Any lost gear associated with the fishery surveys will be 
reported to the NOAA Greater Atlantic Regional Fisheries Office 
Protected Resources Division (GARFO PRD) as soon as possible. 
Therefore, take from fishery surveys will not be discussed further.

Description of Marine Mammals in the Specified Geographical Region

    Thirty-eight marine mammal species and/or stocks under NMFS' 
jurisdiction have geographic ranges within the western North Atlantic 
OCS (Hayes et al., 2023). In the ITA application, SouthCoast identified 
31 of those species that could potentially occur in the Lease Area and 
surrounding waters. However, for reasons described below, SouthCoast 
has requested, and NMFS proposes to authorize, take of only 16 species 
(comprising 16 stocks) of marine mammals. Section 4 of SouthCoast's ITA 
application summarizes available information regarding status and 
trends, distribution and habitat preferences, and behavior and life 
history of the species included in SouthCoast's take estimation 
analyses, except for the Atlantic spotted dolphin as it was 
unintentionally excluded from this section but included in Section 6 
Take Estimates for Marine Mammals. Given previous observations of the 
species in the RI/MA and MA WEAs, SouthCoast included Atlantic spotted 
dolphins take analyses (and Table 5), and is requesting Level B 
harassment take of the species incidental to foundation installation, 
UXO/MEC detonation, and HRG surveys, which NMFS is proposing for 
authorization. NMFS fully considered all available information for the

[[Page 53726]]

potentially affected species, and we refer the reader to Section 4 of 
the ITA application for more details about each species (except the 
Atlantic spotted dolphin) instead of reprinting the information. A 
description of Atlantic spotted dolphin distribution, population 
trends, and life history can be found in the NMFS SAR (Hayes et al., 
2019) (https://media.fisheries.bnoaa.gov/dam-migration/2019_sars_atlantic_atlanticbspottedbdolphin.pdf).
    Additional information regarding population trends and threats may 
be found in NMFS' Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports) and more general information about 
these species (e.g., physical and behavioral descriptions) may be found 
on NMFS' website (https://www.fisheries.noaa.gov/find-species).
    Of the 31 marine mammal species (comprising 31 stocks) SouthCoast 
determined have geographic ranges that include the project area, 14 are 
considered rare or unexpected based on the best scientific information 
available (i.e., sighting and distribution data, low predicted 
densities, and lack of preferred habitat) for a given species. 
SouthCoast did not request, and NMFS is not proposing to authorize, 
take of these species and they are not discussed further in this 
proposed rulemaking: Dwarf and pygmy sperm whales (Kogia sima and K. 
breviceps), Cuvier's beaked whale (Ziphius cavirostris), four species 
of Mesoplodont beaked whales (Mesoplodon densitostris, M. europaeus, M. 
mirus, and M. bidens), killer whale (Orcinus orca), short-finned pilot 
whale (Globicephalus macrohynchus), white-beaked dolphin 
(Lagenorhynchus albirotris), pantropical spotted dolphin (Stenella 
attenuate), and the, striped dolphin (Stenella coeruleoalba). Two 
species of phocid pinnipeds are also uncommon in the project area, 
including: harp seals (Pagophilus groenlandica) and hooded seals 
(Cystophora cristata).
    In addition, the Florida manatee (Trichechus manatus; a sub-species 
of the West Indian manatee) has been previously documented as a rare 
visitor to the Northeast region during summer months (U.S. Fish and 
Wildlife Service (USFWS), 2022). However, manatees are managed by the 
USFWS and are not considered further in this document. More information 
on this species can be found at the following website: https://www.fws.gov/species/manatee-trichechus-manatus.
    Table 5 lists all species or stocks for which take is likely and 
proposed for authorization for this action and summarizes information 
related to the species or stock, including regulatory status under the 
MMPA and Endangered Species Act (ESA) and potential biological removal 
(PBR), where known. PBR is defined 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)). While no mortality is 
anticipated or proposed for authorization, PBR and annual serious 
injury and mortality from anthropogenic sources are included here as 
gross indicators of the status of the species or stocks and other 
threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS' stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS' U.S. Atlantic and Gulf of Mexico SARs. All values presented in 
table 5 are the most recent available at the time of publication and, 
unless noted otherwise, use NMFS' draft 2023 SARs (Hayes et al., 2024) 
available online at https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports.

                    Table 5--Marine Mammal Species \1\ That May Occur in the Specified Geographical Region and Be Taken by Harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                         ESA/ MMPA status;   Stock abundance (CV,
           Common name \1\                Scientific name               Stock             strategic (Y/N)      Nmin, most recent       PBR     Annual M/
                                                                                                \2\          abundance survey) \3\               SI \4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                           Order Artiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenidae:
    North Atlantic right whale......  Eubalaena glacialis....  Western Atlantic.......  E, D, Y             340 (0; 337; 2021);           0.7   \6\ 27.2
                                                                                                             356 (346-363, 2022)
                                                                                                             \5\.
Family Balaenopteridae (rorquals):
    Blue whale......................  Balaenoptera musculus..  Western North Atlantic.  E, D, Y             UNK (UNK; 402; 1980-          0.8          0
                                                                                                             2008).
    Fin whale.......................  Balaenoptera physalus..  Western North Atlantic.  E, D, Y             6,802 (0.24; 5,573;            11       2.05
                                                                                                             2021).
    Sei whale.......................  Balaenoptera borealis..  Nova Scotia............  E, D, Y             6,292 (1.02; 3,098;           6.2        0.6
                                                                                                             2021).
    Minke whale.....................  Balaenoptera             Canadian Eastern         -, -, N             21,968 (0.31; 17,002;         170        9.4
                                       acutorostrata.           Coastal.                                     2021).
    Humpback whale..................  Megaptera novaeangliae.  Gulf of Maine..........  -, -, Y             1,396 (0; 1,380; 2016)         22      12.15
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Physeteridae:
    Sperm whale.....................  Physeter macrocephalus.  North Atlantic.........  E, D, Y             5,895 (0.29; 4,639;          9.28        0.2
                                                                                                             2021).
Family Delphinidae:
    Atlantic white-sided dolphin....  Lagenorhynchus acutus..  Western North Atlantic.  -, -, N             93,233 (0.71; 54,433;         544         28
                                                                                                             2021).
    Atlantic spotted dolphin........  Stenella frontalis.....  Western North Atlantic.  -, -, N             31,506 (0.28; 25,042;         250          0
                                                                                                             2021).
    Bottlenose dolphin \7\..........  Tursiops truncatus.....  Western North Atlantic   -, -, N             64,587 (0.24; 52,801;         507         28
                                                                Offshore.                                    2021) \7\.
    Long-finned pilot whale \8\.....  Globicephala melas.....  Western North Atlantic.  -, -, N             39,215 (0.3; 30,627;          306        5.7
                                                                                                             2021).
    Common dolphin (short-beaked)...  Delphinus delphis......  Western North Atlantic.  -, -, N             93,100 (0.21; 59,817;       1,452        414
                                                                                                             2021).
Risso's dolphin.....................  Grampus griseus........  Western North Atlantic.  -, -, N             44,067 (0.19; 30,662;         307         18
                                                                                                             2021).
Family Phocoenidae (porpoises):

[[Page 53727]]

 
    Harbor porpoise.................  Phocoena phocoena......  Gulf of Maine/Bay of     -, -, N             85,765 (0.53; 56,420;         649         45
                                                                Fundy.                                       2021).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals):
    Gray seal \9\...................  Halichoerus grypus.....  Western North Atlantic.  -, -, N             27,911 (0.20; 23,624;       1,512      4,570
                                                                                                             2021).
    Harbor seal.....................  Phoca vitulina.........  Western North Atlantic.  -, -, N             61,336 (0.08; 57,637;       1,729        339
                                                                                                             2018).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
  (https://www.marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/; Committee on Taxonomy (2022)).
\2\ 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, is
  declining and likely to be listed under the ESA within the foreseeable future, or listed under the ESA. A marine mammal species or population is
  considered depleted under the MMPA if it is below its optimum sustainable population (OSP) level, or is listed as endangered or threatened under the
  ESA.
\3\ CV is the coefficient of variation; Nmin is the minimum estimate of stock abundance.
\4\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike).
\5\ The current SAR includes an estimated population (Nbest 340) based on sighting history through November 2021 (Hayes et al., 2024). In October 2023,
  NMFS released a technical report identifying that the North Atlantic right whale population size based on sighting history through 2022 was 356
  whales, with a 95 percent credible interval ranging from 346 to 363 (Linden, 2023).
\6\ Total annual average observed North Atlantic right whale mortality during the period 2017-2021 was 7.1 animals and annual average observed fishery
  mortality was 4.6 animals. Numbers presented in this table (27.2 total mortality and 176 fishery mortality) are 2016-2020 estimated annual means,
  accounting for undetected mortality and serious injury.
\7\ There are two morphologically and genetically distinct common bottlenose morphotypes, the Western North Atlantic Northern Migratory Coastal stock
  and the Western North Atlantic Offshore stock. The western North Atlantic offshore stock is primarily distributed along the outer shelf and slope from
  Georges Bank to Florida during spring and summer and has been observed in the Gulf of Maine during late summer and fall (Hayes et al. 2020), whereas
  the northern migratory coastal stock is distributed along the coast between southern Long Island, New York, and Florida (Hayes et al., 2018). Given
  their distribution, only the offshore stock of bottlenose dolphins is likely to occur in the project area.
\8\ There are two pilot whale species, long-finned (Globicephala melas) and short-finned (Globicephala macrorhynchus), with distributions that overlap
  in the latitudinal range of the SouthCoast Project (Hayes et al., 2020; Roberts et al., 2016). Because it is difficult to differentiate between the
  two species at sea, sightings, and thus the densities calculated from them, are generally reported together as Globicephala spp. (Roberts et al.,
  2016; Hayes et al., 2020). However, based on the best available information, short-finned pilot whales occur in habitat that is both further offshore
  on the shelf break and further south than the project area (Hayes et al., 2020). Therefore, NMFS assumes that any take of pilot whales would be of
  long-finned pilot whales.
\9\ 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.

    As indicated above, all 16 species and stocks in table 5 temporally 
and spatially co-occur with the activity to the degree that take is 
likely to occur. Five of the marine mammal species for which take is 
requested are listed as 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 SouthCoast's ITA application (https://www.fisheries.noaa.gov/action/incidental-take-authorization-southcoast-wind-llc-construction-southcoast-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 UMEs and known important habitat areas, 
such as Biologically Important Areas (BIAs; https://oceannoise.noaa.gov/biologically-important-areas) (Van Parijs et al., 
2015)). There are no ESA-designated critical habitats for any species 
within the project area.
    Under the MMPA, a UME is defined as ``a stranding that is 
unexpected; involves a significant die-off of any marine mammal 
population; and demands immediate response'' (16 U.S.C. 1421h(6)). As 
of May 20, 2024, four UMEs are active. Below we include information for 
species that are listed under the ESA, 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 
within the project area.

North Atlantic Right Whale

    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., 2021; Reed et al., 
2022). There is a recovery plan (NOAA Fisheries, 2005) for the North 
Atlantic right whale and, in November 2022, NMFS completed the 5-year 
review and concluded that no change to this listing status is 
warranted. (https://www.fisheries.noaa.gov/resource/document/north-atlantic-right-whale-5-year-review). 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., 2023). Since 2010, the North 
Atlantic right whale population has been in decline; however, the sharp 
decrease observed from 2015 to 2020 appears to have slowed, though the 
North Atlantic right whale population continues to experience annual 
mortalities above recovery thresholds (Pace et al., 2017; Pace et al., 
2021; Linden, 2023). 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

[[Page 53728]]

during the 2021-2022 calving season and 12 births in the 2022-2023 
calving season. As of May 20, 2024, the 2023-2024 calving season 
includes 19 births. However, mortalities continue to outpace births, 
including three calf mortalities/presumed mortalities during the 2024 
calving season, and the best estimates indicate fewer than 70 
reproductively active females remain in the population (Hayes et al., 
2024). North Atlantic right whale total annual mortality and serious 
injury (M/SI) estimates have fluctuated in recent years, as presented 
in annual stock assessment reports. The estimate for 2022 (31.2) was a 
marked increase over the previous year. In the 2022 SARs, Hayes et al., 
(2023) report the total annual North Atlantic right whale mortality 
increased from 8.1 (which represents 2016-2020) to 31.2 (which 
represents 2015-2019), however, this updated estimate also accounted 
for undetected mortality and serious injury (Hayes et al., 2024). 
Presently, the best available peer-reviewed population estimate for 
North Atlantic right whales is 340 per the draft 2023 SARs (Hayes et 
al., 2024). 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; Pirotta et al., 2024). Body size is generally 
positively correlated to reproductive potential. Pirrota et al. (2024) 
found North Atlantic right whale body size was strongly associated with 
the probability of giving birth to a calf, such that smaller body size 
was associated with lower reproductive output. In turn, shorter females 
that do calve tend to produce offspring with a limited maximum size, 
likely through a combination of genetics and the influence of body 
condition during gestation and weaning (Pirotta et al., 2024). When 
combined with other factors (e.g., health deterioration due to 
sublethal effects of entanglement), this feedback loop has led to a 
decrease in overall body length and fecundity over the past 50 years 
(Pirotta et al., 2023; Pirotta et al., 2024).
    Since 2017, dead, seriously injured, sublethally injured, or ill 
North Atlantic right whales along the United States 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 20, 2024, there have been 39 confirmed 
mortalities (dead, stranded, or floaters), 1 pending mortality, and 34 
seriously injured free-swimming whales for a total of 74 whales. The 
UME also considers animals with sublethal injury or illness (i.e., 
``morbidity''; n=51) bringing the total number of whales in the UME 
from 71 to 122. 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.
    The project area both spatially and temporally overlaps the 
migratory corridor BIA, within which a portion of the North Atlantic 
right whale population migrates south to calving grounds, generally in 
November and December, followed by a northward migration into feeding 
areas east and north of the project area in March and April (LaBrecque 
et al., 2015; Van Parijs et al., 2015). While the Project does not 
overlap previously identified critical feeding habitat or a feeding 
BIA, it is located within a recently described important feeding area 
south of Martha's Vineyard and Nantucket, primarily along the western 
side of Nantucket Shoals (Kraus et al., 2016; O'Brien et al., 2022, 
Quintano-Rizzo et al., 2021). Finally, the Project overlaps the 
currently established November 1 through April 30th Block Island 
Seasonal Management Area (SMA) (73 FR 60173, October 10, 2008) and the 
proposed November 1 through May 30 Atlantic Seasonal Speed Zone (87 FR 
46921, August 1, 2022), which may be used by North Atlantic right 
whales for various activities, including feeding and migration. Due to 
the current status of North Atlantic right whales and the overlap of 
the proposed Project with areas of biological significance (i.e., a 
migratory corridor, feeding habitat, SMA), the potential impacts of the 
proposed SouthCoast project on North Atlantic right whales warrant 
particular attention.
    Recent research indicates that the overall understanding of North 
Atlantic right whale 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; O'Brien et al., 
2022; Estabrook et al., 2022; Davis et al., 2023; van Parijs et al., 
2023). The seasonal migration between northern feeding grounds, mating 
grounds, and southern calving grounds off Florida and Georgia involves 
a part of the population while the remaining whales overwinter in other 
widely distributed areas (Morano et al., 2012, Cole et al., 2013, Bort 
et al., 2015, Davis et al., 2017). 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 habitat during winter in the years preceding and following 
the birth of a calf to increase their energy stores (Gowen et al., 
2019). O' Brien et al. (2022) hypothesized that North Atlantic right 
whales might gain an energetic advantage by summertime foraging in 
southern New England on sub-optimal prey patches rather than engaging 
in the extensive migration required to access more high-quality prey 
patches in northern feeding habitats (e.g., Gulf of St. Lawrence). 
These observations of transitions in North Atlantic right whale habitat 
use, variability in seasonal presence in identified core habitats, and 
utilization of habitat outside of previously focused survey effort 
prompted the formation of a NMFS' Expert Working Group, which 
identified current data collection efforts, data gaps, and provided 
recommendations for future survey and research efforts (Oleson et al., 
2020).
    North Atlantic right whale distribution and demography has been 
shown to depend on the distribution and density of zooplankton, which 
varies spatially and temporily. North Atlantic right whales feed on 
high-density patches of different zooplankton species (e.g., calanoid 
copepods, Centrophages spp., Pseudocalanus spp.), but primarily on 
aggregations of late-stage Calanus finmarchicus, a species whose 
seasonal availability and distribution has changed both spatially and 
temporally over the last decade due to an oceanographic regime shift 
that has ultimately been linked to climate change (Meyer-Gutbrod et 
al., 2021; Meyer-Gutbrod et al., 2023; 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 over the same 
time period (Davis et al., 2020; Meyer-Gutbrod et al., 2022; Quintano-
Rizzo et al., 2021; O'Brien et al., 2022) with reduced use of foraging 
habitats in the Great South Channel and Bay of Fundy and increased use 
of habitat within Cape Cod Bay (Stone et al., 2017; Mayo et al., 2018; 
Ganley et al., 2019; Record et al., 2019; Meyer-Gutbrod et al., 2021; 
O'Brien et al., 2022; Davis et al., 2017). North Atlantic right whales 
have recolonized areas that have not had large numbers of right whales 
since the whaling era, likely in response to changes in zooplankton 
distribution (e.g., Gulf of St. Lawrence, Simard et al.,

[[Page 53729]]

2019; Nantucket Shoals, e.g., Kraus et al., 2016; Quintana-Rizzo et 
al., 2021; O'Brien et al., 2022; Davis et al., 2023; Ganley et al., 
2022; Van Parijs et al., 2023).
    Pendleton et al. (2022) found that peak use of North Atlantic right 
whale foraging habitat in Cape Cod Bay, north of the Lease Area, has 
shifted over the past 20 years to later in the spring, likely due to 
variations in seasonal conditions. However, initial yearly sightings of 
individual North Atlantic right whales in Cape Cod Bay have started 
earlier in the year concurrent with climate changes, indicating that 
their migratory movements between habitats may be cued by changes in 
regional water temperature (Pendleton et al., 2022). These changes have 
the potential to lead to temporal misalignment between North Atlantic 
right whale seasonal arrival to this foraging habitat and the 
availability of the zooplankton prey (Ganley et al., 2022).
    North Atlantic right whale use of habitats such as in the Gulf of 
St. Lawrence and East Coast mid-Atlantic waters of the U.S. have also 
increased over time (Davis et al., 2017; Davis and Brillant, 2019; 
Simard et al., 2019; Crowe et al., 2021; Quintana-Rizzo et al., 2021). 
Using passive acoustic data collected from 2010-2018 throughout the 
Gulf of St. Lawrence, a foraging habitat more recently exploited by a 
significant portion of the population, Simard et al. (2019) documented 
the presence of North Atlantic right whales for an unexpectedly 
extended period at four out of the eight recording stations, from the 
end of April through January, and found that occurrence peaked in the 
area from August through November each year. In 2015, the mean daily 
occurrence of North Atlantic right whales in the feeding grounds off 
Gasp[eacute], located on the west side of the upper Gulf of St. 
Lawrence, quadrupled compared to 2011-2014 (Simard et al., 2019). 
However, there is concern that prey biomass in the Gulf of St. Lawrence 
may be insufficient in most years to support successful reproduction of 
North Atlantic right whales (Gavrilchuk et al., 2021), which could 
impel whales to seek out alternative foraging habitats. Based on high-
resolution climate models, Ross et al., (2021) projected that the 
redistribution of North Atlantic right whales throughout the western 
North Atlantic Ocean will continue at least through the year 2050 (Ross 
et al., 2021).
    Within the past decade in southern New England, increasing year-
round observations of North Atlantic right whales have occurred and 
include documentation of social behaviors and foraging in all seasons, 
making it the only known winter foraging habitat (Kraus et al., 2016; 
Leiter et al., 2017; Stone et al., 2017; Quintana-Rizzo et al., 2021; 
O'Brien et al., 2022; Van Parijs et al., 2023; Davis et al., 2023). 
Both visual and acoustic lines of evidence demonstrate the year-round 
presence of North Atlantic right whales in southern New England (Kraus 
et al., 2016; Quintana-Rizzo et al. 2021; Estabrook et al., 2022; 
O'Brian et al., 2022; Davis et al., 2023; van Parijs et al., 2023). 
Right whales were sighted in winter and spring during aerial surveys 
conducted in the RI/MA and MA WEAs from 2011-2015 and 2017-2019 (Kraus 
et al., 2016; Quintana-Rizzo et al., 2021; O'Brien et al., 2022). There 
was not significant variability in sighting rates among years, 
indicating consistent annual seasonal use of the area by North Atlantic 
right whales. Despite the lack of visual detection in most summer and 
fall months, right whales were acoustically detected in 30 out of the 
36 recorded months (Kraus et al., 2016). Since 2017, whales have been 
sighted in southern New England nearly every month with peak sighting 
rates between late winter and spring. Model outputs in Quintana-Rizzo 
et al. (2021) suggested that 23 percent of the right whale population 
is present from December through May, and the mean residence time 
tripled between 2011-2015 and 2017-2019 to an average of 13 days during 
these same months.
    Based on analyses of PAM data collected at recording sites in the 
RI/MA and MA WEAs from 2011-2015, Estabrook et al. (2022) report that 
North Atlantic right whale upcall detections occurred throughout both 
WEAs in all seasons (during 34 of the 37 surveyed months) but 
predominantly in the late winter and spring, which aligns with visual 
observations (Kraus et al., 2016; Quintana-Rizzo et al., 2021). Among 
the recording locations in southern New England, detections were most 
frequent on acoustic recorders along the eastern side of the MA WEA 
(Estabrook et al., 2022). December through April had higher presence 
while June through September had lower presence. Winter (December-
April) had the highest presence (75 percent array-days, n = 193), and 
summer (June-Sep had the lowest presence (10 percent array-days, n = 
27). Spring and autumn were similar, where approximately half of the 
array-days had upcall detections. The mean daily call rate for days 
upcalls were detected was highest in January, February, and March, 
accounting for 72 percent of all detected upcalls, and calling rates 
were significantly different among seasons (Estabrook et al., 2022). 
Upcalls were detected on 41 percent of the 1,023 recording days in the 
MA WEA and on only 24 percent of the recording days in the RI-MA WEA. 
Similarly, both van Parijs et al. (2023) and. Davis et al. (2023) 
evaluated a 2020-2022 PAM dataset collected using seven acoustic 
recorders deployed in the RI/MA and MA WEAs, two deployed on Cox Ledge 
(i.e., the northwest side of the RI/MA WEA), four along the eastern 
side of the MA WEA (along a transect approximately parallel to the 30-m 
isobath on the west side of Nantucket Shoals, the same bathymetric 
feature used to define the NARW EMA), and one positioned towards the 
center of Nantucket Shoals, and noted that North Atlantic right whales 
were acoustically detected at all seven sites from September through 
May, with sporadic presence in June through August. Upcalls were 
detected at each location nearly every week, annually, with detections 
steadily increasing through October, reaching consistently high levels 
from November through April, steadily declining in May, and remaining 
low throughout summer. Upcalls were detected nearly 7 days a week 
December through March at the two locations nearest the Lease Area 
along the eastern edge of the MA WEA (NS01 and NS02, see Figures 1 and 
2 in Davis et al., 2023). Comprehensively, acoustic and visual 
observations of North Atlantic right whales in southern New England 
indicate that whales occur year-round but more frequently in winter and 
spring and in eastern (versus western) southern New England.
    While Nantucket Shoals is not designated as critical North Atlantic 
right whale habitat, its importance as a foraging habitat is well 
established (Leiter et al., 2017; Quintana-Rizzo et al., 2021; 
Estabrook et al., 2022; O'Brien et al., 2022). However, studies 
focusing on the link between right whale habitat use and zooplankton in 
the Nantucket Shoals region are limited (National Academy of Sciences, 
2003). The supply of zooplankton to the Nantucket Shoals region is 
dependent on advection from sources outside the Shoals via regional 
circulation, but zooplankton aggregation is presumably dependent on 
local physical processes and zooplankton behavior (National Academy of 
Sciences, 2023). Nantucket Shoals' unique oceanographic and bathymetric 
features, including the persistent tidal front described in the 
Specified Geographical Area section, help sustain year-round elevated 
phytoplankton biomass and aggregate zooplankton prey for North Atlantic 
right whales (White et

[[Page 53730]]

al., 2020; Quintana-Rizzo et al., 2021). O'Brien et al. (2022) 
hypothesize that North Atlantic right whale southern New England 
habitat use has increased in recent years (i.e., over the last decade) 
as a result of either, or a combination of, a northward shift in prey 
distribution (thus increasing local prey availability) or a decline in 
prey in other abandoned feeding areas (e.g., Gulf of Maine), both 
induced by climate change. Pendleton et al. (2022) characterize 
southern New England as a ``waiting room'' for North Atlantic right 
whales in the spring, providing sufficient, although sub-optimal, prey 
choices while North Atlantic right whales wait for Calanus finmarchicus 
supplies in Cape Cod Bay (and other primary foraging grounds like the 
Great South Channel) to optimize as seasonal primary and secondary 
production progresses. Throughout the year, southern New England 
provides opportunities for North Atlantic right whales to capitalize on 
C.finmarchicus blooms or alternative prey (e.g., Pseudocalanus 
elongatus and Centropages spp., found in greater concentrations than 
C.finmarchicus in winter), although likely not to the extent provided 
seasonally in more well-understood feeding habitats like Cape Cod Bay 
in late spring or the Great South Channel (O'Brien et al., 2022). 
Although extensive data gaps, highlighted in a recent report by the 
National Academy of Sciences (NAS, 2023), have prevented development of 
a thorough understanding of North Atlantic right whale foraging ecology 
in the Nantucket Shoals region, it is clear that the habitat was 
historically valuable to the species, given that the whaling industry 
capitalized on consistent right whale occurrence there and has again 
become increasingly so over the last decade.

Humpback Whale

    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 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 2004-2005, 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).
    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 (LeBrecque et al., 2015). However, this BIA is located further 
east and north of, and thus, does not overlap the project area.
    Kraus et al. (2016) visually observed humpback whales in the RI/MA 
and MA WEAs and surrounding areas during all seasons, but most 
frequently during spring and summer months, particularly from April to 
June. Concurrently collected acoustic data (from 2011 through 2015) 
indicated 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). Analyzing PAM data collected at six 
acoustic recording locations from January 2020 through November 2022, 
van Parijs et al. (2023) assessed daily, weekly, and monthly patterns 
in humpback whale acoustic occurrence within the RI/MA and MA WEAs, and 
found patterns similar to those described in Kraus et al. (2016). 
Humpback whale vocalizations were detected in all months, although most 
commonly from November through June, annually, at recording sites in 
eastern southern New England (near Nantucket Shoals) (van Parijs et al. 
2023). Detections at recorder locations in western southern New 
England, near Cox Ledge, were even more frequent than at the eastern 
southern New England recorder locations, indicating humpback whales 
were present on a nearly daily basis in all months except September and 
October.
    In New England waters, feeding is the principal activity of 
humpback whales, and their distribution in this region has been largely 
correlated to abundance of prey species, although behavior and 
bathymetry are factors influencing foraging strategy (Payne et al., 
1986; 1990). Humpback whales are frequently piscivorous when in New 
England waters, feeding on herring (Clupea harengus), sand lance 
(Ammodytes spp.), and other small fishes, as well as euphausiids in the 
northern Gulf of Maine (Paquet et al., 1997). During winter, the 
majority of humpback whales from North Atlantic feeding areas 
(including the Gulf of Maine) mate and calve in the West Indies, where 
spatial and genetic mixing among feeding groups occurs, though 
significant numbers of animals are found in mid- and high-latitude 
regions at this time and some individuals have been sighted repeatedly 
within the same winter season, indicating that not all humpback whales 
migrate south every winter (Hayes et al., 2018).
    Since January 2016, elevated humpback whale mortalities have 
occurred along the Atlantic coast from Maine to Florida. This event was 
declared a UME in April 2017. Partial or full necropsy examinations 
have been conducted on approximately half of the 212 known cases (as of 
January 5, 2024). Of the whales examined (approximately 90), about 40 
percent had evidence of human interaction either from vessel strike or 
entanglement. While a portion of the whales have shown evidence of pre-
mortem vessel strike, this finding is not consistent across all whales 
examined and more research is needed. NOAA is consulting with 
researchers that are conducting studies on the humpback whale 
populations, and these efforts may provide information on changes in 
whale distribution and habitat use that could provide additional 
insight into how these vessel interactions occurred. More information 
is available at: https://www.fisheries.noaa.gov/national/marine-life-distress/active-and-closed-unusual-mortality-events.
    Since December 1, 2022, the number of humpback strandings along the 
mid-Atlantic coast has been elevated. In some cases, the cause of death 
is not yet known. In others, vessel strike has been deemed the cause of 
death. As the humpback whale population has grown, they are seen more 
often in the Mid-Atlantic. These whales may be following their prey 
(small fish) which were reportedly close to shore in the 2022-2033 
winter. Changing distributions of prey impact larger marine species 
that depend on them and result in changing distribution of whales and 
other marine life. These prey also attract fish that are targeted by 
recreational and commercial fishermen, which increases the number of 
boats and amount of fishing gear in these areas. This nearshore 
movement increases the potential for anthropogenic interactions, 
particularly as the increased presence of whales in areas traveled by 
boats of all sizes increases the risk of vessel strikes.

Minke Whale

    Minke whales are common and widely distributed throughout the U.S.

[[Page 53731]]

Atlantic Exclusive Economic Zone (EEZ) (Cetacean and Turtle Assessment 
Program (CETAP), 1982; Hayes et al., 2022), although their distribution 
has a strong seasonal component. Individuals have often been detected 
acoustically in shelf waters from spring to fall and more often 
detected in deeper offshore waters from winter to spring (Risch et al., 
2013). Minke whales are abundant in New England waters from May through 
September (Pittman et al., 2006; Waring et al., 2014), yet largely 
absent from these areas during the winter, suggesting the possible 
existence of a migratory corridor (LaBrecque et al., 2015). A migratory 
route for minke whales transiting between northern feeding grounds and 
southern breeding areas may exist to the east of the Lease Area, as 
minke whales may track warmer waters along the continental shelf while 
migrating (Risch et al., 2014). Risch et al. (2014) suggests the 
presence of a minke whale breeding ground offshore of the southeastern 
U.S. during the winter.
    There are two minke whale feeding BIAs from March through November, 
annually, identified in the southern and southwestern sections of the 
Gulf of Maine, including multiple habitats: Georges Bank, the Great 
South Channel, Cape Cod Bay and Massachusetts Bay, Stellwagen Bank, 
Cape Anne, and Jeffreys Ledge (LeBrecque et al., 2015). However, these 
BIAs do not overlap the Lease Area or ECCs, as they are located further 
east and north.
    Although minke whales are sighted in every season in southern New 
England (O'Brien et al., 2022), minke whale use of the area is highest 
during the months of March through September (Kraus et al., 2016; 
O'Brien et al., 2023), and the species is largely absent in the winter 
(Risch et al., 2013; Hayes et al., 2023). Large feeding aggregations of 
humpback, fin, and minke whales have been observed during the summer 
(O'Brien et al., 2023), suggesting southern New England may serve as a 
supplemental feeding grounds for these species. Aerial survey data 
indicate that minke whales are the most common baleen whale in the RI/
MA & MA WEAs (Kraus et al., 2016; Quintana and Kraus, 2019; O'Brien et 
al., 2021a, b). Surveys also reported a shift in the greatest seasonal 
abundance of minke whales from spring (2017-2018) (Quintana and Kraus, 
2019) to summer (2018-2019 and 2020-2021) (O'Brien et al., 2021a, b). 
Through analysis of PAM data collected in southern New England from 
January 2020 through November 2022, Van Parijs et al. (2023) detected 
minke whales at all seven passive acoustic recorder deployment sites, 
primarily from March through June and August through early December. 
Additional detections occurred in January on Cox Ledge and near the 
northeast portion of the Lease Area.
    Elevated minke whale mortalities detected along the Atlantic coast 
from Maine through South Carolina resulted in the declaration of an on-
going UME in 2017. As of May 20, 2024, a total of 169 minke whales have 
stranded during this UME. Full or partial necropsy examinations were 
conducted on more than 60 percent of the whales. Preliminary findings 
show 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 south of Newfoundland (Mitchell, 1975; Hain et al., 
1985; 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, and acoustic occurrence 
has been increasing in the mid-Atlantic region since 2010 (Davis et 
al., 2020).
    Sei whales are largely planktivorous, feeding primarily on 
euphausiids and copepods (Hayes et al., 2023). Although their migratory 
movements are not well understood, sei whales are believed to migrate 
between feeding grounds in temperate and subpolar regions to wintering 
grounds in lower latitudes (Kenney and Vigness-Raposa, 2010; Hayes et 
al., 2020). Through an analysis of PAM data collected from X to X, 
Davis et al. (2020) determined that peak call detections occurred in 
northern latitudes during summer, ranging from Southern New England 
through the Scotian Shelf. During spring and summer, the stock is 
mainly concentrated in these 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). While sei whales generally occur 
offshore, individuals may also move into shallower, more inshore waters 
to pursue prey (Payne et al., 1990; Halpin et al., 2009; Hayes et al., 
2023).
    A sei whale feeding BIA occurs in New England waters from May 
through November (LaBrecque et al., 2015). This BIA is located over 100 
km to the east and north of the project area and is not expected to be 
impacted by the Project activities.
    Persistent year-round detections in southern New England and the 
New York Bight indicate that sei whales may utilize these habitats to a 
greater extent than previously thought (Hayes et al., 2023). The 
results of an analysis of acoustic data collected from January 2020 
through November 2022 indicate that sei whale acoustic presence in 
southern New England peaks in late winter and early spring (February to 
May), and is otherwise sporadic throughout the rest of the year (van 
Parijs et al., 2023). Fewer detections occurred at the two sites on Cox 
Ledge to the west compared to the sites located near the eastern edge 
of the MA WEA, potentially indicating sei whales prefer specific 
habitat within southern New England (Figure 1 in van Parijs et al., 
2023).

Fin Whale

    Fin whales frequently occur in the waters of the U.S. Atlantic 
Exclusive EEZ, principally from Cape Hatteras, North Carolina northward 
and are distributed in both continental shelf and deep-water habitats 
(Hayes et al., 2023). Although fin whales are present north of the 35-
degree latitude region in every season and are broadly distributed 
throughout the western North Atlantic for most of the year, densities 
vary seasonally (Edwards et al., 2015; Hayes et al., 2023). 
Observations of fin whales indicate that they 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., 2021). Acoustic detections of fin whale 
singers augment and confirm these conclusions for males drawn from 
visual sightings. Recordings from Massachusetts Bay, New York Bight, 
and deep-ocean areas have detected some level of fin whale singing from 
September through June (Watkins et al., 1987; Clark and Gagnon, 2002; 
Morano et al., 2012). These acoustic observations from both coastal and 
deep-ocean regions support the conclusion that male fin whales are 
broadly distributed throughout the western North Atlantic for most of 
the year (Hayes et al., 2019).
    New England waters represent a major feeding ground for fin whales. 
A relatively small fin whale feeding BIA (2,933 km\2\), active from 
March through October, is located approximately 34 km

[[Page 53732]]

to the west of the Lease Area, offshore of Montauk Point, New York 
(Hain et al., 1992; LaBrecque et al. 2015). A portion of the planned 
Brayton Point ECC route traces the northeast edge of the BIA. Although 
the Lease Area does not overlap this BIA, should SouthCoast decide to 
use vibratory pile driving to install foundations for Project 2, it's 
possible that the resulting Level B harassment zone may extend into the 
southeastern edge of the BIA during installation of the foundations on 
the northwest edge of the Lease Area. 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.
    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. 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). 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 to a much lesser extent in summer (Morano et al., 2012; 
Muirhead et al., 2018; Davis et al., 2020). More recent surveys have 
documented fin whales throughout winter, spring, and summer (O'Brien et 
al., 2020; 2021; 2022; 2023) with the greatest abundance occurring 
during the summer and clustered in the western portion of the WEAs 
(O'Brien et al., 2023). Most recently, from January 2020 through 
November 2022, van Parijs et al. (2023) fin whales were acoustically 
detected at all seven recording sites in southern New England, which 
included two locations on Cox Ledge (western southern New England) and 
five locations along the east side of the MA WEA (along the western 
side of Nantucket Shoals). Similar to observations of humpback whale 
acoustic occurrence, fin whales were detected more frequently near Cox 
Ledge than at locations closer to Nantucket Shoals (van Paris et al. 
(2023). Daily acoustic presence occurred for the majority of the year, 
most intensively in the fall, yet fin whales were essentially 
acoustically absent at all recorder locations from April through August 
(van Parijs et al., 2023). Although fin whale distribution is not fully 
understood, we expect that this period lacking acoustic detections 
corresponds to fin whale northward movement in late spring towards 
higher-latitude foraging grounds.

Blue Whale

    Much is unknown about the blue whale populations. The last minimum 
population abundance was estimated at 402, but insufficient data 
prevent determining population trends (Hayes et al., 2023). 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 habitats identified in the project area or 
along the U.S. Eastern Seaboard. There is no UME for blue whales.
    In the North Atlantic Ocean, blue whales range from the subtropics 
to the Greenland Sea. The North Atlantic Stock includes animals 
utilizing mid-latitude (North Carolina coastal and open ocean) to 
Arctic (Newfoundland and Labrador) waters. Blue whales do not regularly 
occur within the U.S. EEZ, preferring offshore habitat with water 
depths of 328 ft (100 m) or more (Waring et al., 2011). The most 
frequent sightings occur at higher latitudes off eastern Canada in the 
Gulf of St. Lawrence, with the greatest concentration of this species 
in the St. Lawrence Estuary (Comtois et al., 2010; Lesage et al., 2007; 
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).
    Blue whales are uncommon in New England coastal waters. Visual 
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, Kraus et al. (2016) conducted aerial and acoustic 
surveys between 2011-2015 in the MA and RI/MA WEAs and surrounding 
areas and, although blue whales were not visually observed, they were 
infrequently acoustically detected during winter. A 2008 study detected 
blue whale calls in offshore areas of the New York Bight, south of 
southern New England, on 28 out of 258 days of recordings (11 percent 
of recording days), mostly during winter (Muirhead et al., 2018). Van 
Paris et al. (2023) detected a small number of blue whale calls in 
southern New England in January and February, although the species was 
otherwise acoustically absent. Given the long-distance propagation 
characteristics of low-frequency blue whale vocalizations, it's 
possible blue whale calls detected in southern New England originated 
from distant whales. Together, these data suggest that blue whales are 
rarely present in the MA and RI/MA WEAs.

Sperm Whale

    Sperm whales can be found throughout the world's oceans. They can 
be found near the edge of the ice pack in both hemispheres and are also 
common along the equator. The North Atlantic stock is distributed 
mainly along the continental shelf-edge, over the continental slope, 
and mid-ocean regions, where they prefer water depths of 600 m (1,969 
ft) or more and are less common in waters <300 m (984 ft) deep (Waring 
et al., 2015; Hayes et al., 2020). In the winter, sperm whales are 
observed east and northeast of Cape Hatteras. In the spring, sperm 
whales are more widely distributed throughout the Mid-Atlantic Bight 
and southern portions of George's Bank (Hayes et al., 2020). In the 
summer, sperm whale distribution is similar to the spring, but they are 
more widespread in Georges Bank and the Northeast Channel region and 
are also observed inshore of the 100-m (328-ft) isobath south of New 
England (Hayes et al., 2020). Sperm whale occurrence on the continental 
shelf in areas south of New England is at its highest in the fall 
(Hayes et al., 2020). Between April 2020 and December 2021, there was 1 
sighting of 2 individual sperm whales recorded during HRG surveys 
conducted within the area surrounding the Lease Area and Falmouth ECC.
    Kraus et al. (2016) observed sperm whales four times in the RI/MA 
and MA WEAs and surrounding areas in the summer and fall during the 
2011-2015 NLPSC aerial survey. Sperm whales, traveling singly or in 
groups of three or four, were observed three times in August and 
September of 2012, and once in June of 2015. Effort-weighted average 
sighting rates could not be calculated. The frequency of sperm whale 
clicks exceeded the maximum frequency of PAM equipment used in the 
Kraus et al. (2016) study, so no acoustic data are available for this 
species from that study. Sperm whales were observed only once in the MA 
WEA and nearby waters during the 2010-2017 AMAPPS surveys (NEFSC and 
SEFSC 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018). This occurred 
during a summer shipboard survey in 2016.

[[Page 53733]]

Phocid Seals

    Harbor and gray seals have experienced two UMEs since 2018, 
although one was recently closed (2022 Pinniped UME in Maine) and 
closure of the second, described here, 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 were 
conducted on some of the seals and samples were 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.

           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 2019, Southall et al. recommended new names for 
hearing groups that are widely recognized. However, this new hearing 
group classification does not change the weighting functions or 
acoustic thresholds (i.e., the weighting functions and thresholds in 
Southall et al. (2019) are identical to NMFS 2018 Revised Technical 
Guidance). When NMFS updates our Technical Guidance, we will be 
adopting the updated Southall et al. (2019) hearing group 
classification.

Acoustic Habitat

    Acoustic habitat is defined as distinguishable soundscapes 
inhabited by individual animals or assemblages of species, inclusive of 
both the sounds they create and those they hear (NOAA, 2016). All of 
the sound present in a particular location and time, considered as a 
whole, comprises a ``soundscape'' (Pijanowski et al., 2011). When 
examined from the perspective of the animals experiencing it, a 
soundscape may also be referred to as ``acoustic habitat'' (Clark et 
al., 2009, Moore et al., 2012, Merchant et al., 2015). High value 
acoustic habitats, which vary spectrally, spatially, and temporally, 
support critical life functions (feeding, breeding, and survival) of 
their inhabitants. Thus, it is important to consider acute (e.g., 
stress or missed feeding/breeding opportunities) and chronic effects 
(e.g., masking) of noise on important acoustic habitats. Effects that 
accumulate over long periods can ultimately result in detrimental 
impacts on the individual, stability of a population, or ecosystems 
that they inhabit.

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 section later in this document 
includes a quantitative analysis of the number of individuals that are 
expected to be taken by this activity. The Negligible Impact Analysis 
and Determination section considers the content of this section, the 
Estimated Take section, and the Proposed Mitigation section, to draw 
conclusions regarding the likely impacts of these activities on the 
reproductive success or survivorship of individuals and how those 
impacts on individuals are likely to impact marine mammal species or 
stocks. General background information on marine mammal hearing was 
provided previously (see the Description of Marine Mammals in the 
Specified Geographical Area section). Here, the potential effects of 
sound on marine mammals are discussed.

[[Page 53734]]

    SouthCoast has requested, and NMFS proposes to authorize, the take 
of marine mammals incidental to the construction activities associated 
with the SouthCoast project. In their application, SouthCoast presented 
their analyses of potential impacts to marine mammals from the 
specified activities. NMFS carefully reviewed the information provided 
by SouthCoast and also independently reviewed applicable scientific 
research and literature and other information to evaluate the potential 
effects of SouthCoast's specified activities on marine mammals.
    The proposed activities would result in the construction and 
placement of up to 149 permanent foundations (up to 147 WTGs; up to 5 
OSPs) in the marine environment. Up to 10 UXO/MEC detonations may occur 
during construction if any found UXO/MEC cannot be 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 
SouthCoast's specified activities. 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 SouthCoast's 
specified activities, with consideration of select 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.
    The basic components of a sound wave are frequency, wavelength, 
velocity, and amplitude. Frequency is the number of pressure waves that 
pass by a reference point per unit of time and is measured in Hz or 
cycles per second. Wavelength is the distance between two peaks or 
corresponding points of a sound wave (length of one cycle). Higher 
frequency sounds have shorter wavelengths than lower frequency sounds 
and typically attenuate (decrease) more rapidly except in certain cases 
in shallower water. The intensity (or amplitude) of sounds are measured 
in decibels (dB), which are a relative unit of measurement that is used 
to express the ratio of one value of a power or field to another. 
Decibels are measured on a logarithmic scale, so a small change in dB 
corresponds to large changes in sound pressure. For example, a 10-dB 
increase is a ten-fold increase in acoustic power. A 20-dB increase is 
then a 100-fold increase in power and a 30-dB increase is a 1,000-fold 
increase in power. However, a ten-fold increase in acoustic power does 
not mean that the sound is perceived as being ten times louder. 
Decibels are a relative unit comparing two pressures; therefore, a 
reference pressure must always be indicated. For underwater sound, this 
is 1 microPascal ([mu]Pa). For in-air sound, the reference pressure is 
20 [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.
    Sound is generally defined using common metrics. 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 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. Thes 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

[[Page 53735]]

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 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 that would be produced by SouthCoast's activities, 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; Erbe et al., 2016, 2019). 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). Potential effects from 
explosive sound sources can range in severity from behavioral 
disturbance or tactile perception to physical discomfort, slight injury 
of the internal organs and the auditory system, or mortality (Yelverton 
et al., 1973; Siebert et al., 2022).
    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 SouthCoast.
    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.

[[Page 53736]]

    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 SouthCoast 
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 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 with 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 (Neophocoena asiaeorientalis)) 
and six species of pinnipeds (northern elephant seal (Mirounga 
angustirostris), harbor seal, ring seal, spotted seal, bearded seal, 
and California sea lion (Zalophus californianus)) that were exposed to 
a limited number of sound sources (i.e., mostly tones and octave-band 
noise with limited number of exposure to impulsive sources such as 
seismic airguns or impact pile driving) in laboratory settings 
(Southall et al., 2019). There is currently no data available on noise-
induced hearing loss for mysticetes. For summaries of data on TTS or 
PTS in marine mammals or for further discussion of TTS or PTS onset 
thresholds, please see Southall et al. (2019), and NMFS (2018).
    Recent studies with captive odontocete species (bottlenose dolphin, 
harbor porpoise, beluga, and false killer whale) have observed 
increases in hearing threshold levels when individuals received a 
warning sound prior to exposure to a relatively loud sound (Nachtigall 
and Supin, 2013, 2015; Nachtigall et al., 2016a, 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.,

[[Page 53737]]

2013; Ellison et al., 2012; Gomez et al., 2016; Southall et al., 2021; 
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 versus 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 and 
Doukara, 2012). For example, Goldbogen et al. (2013b) demonstrated that 
individual behavioral state was critically important in determining 
response of blue whales to sonar, noting that some individuals engaged 
in deep (greater than 50 m) feeding behavior had greater dive responses 
than those in shallow feeding or non-feeding conditions. Some blue 
whales in the Goldbogen et al. (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 1mPa)by ceasing normal fluking and 
echolocation, swimming rapidly away, and extending both dive duration 
and subsequent non-foraging intervals when the sound source was 3.4-9.5 
km (2.1-5.9 mi) away. Importantly, this study also showed that whales 
exposed to a similar range of received levels (78-106 dB re 1mPa) from 
distant sonar exercises (118 km (73 mi) 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., 2019b).
    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

[[Page 53738]]

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 five-fold increase in the ability to quantify 
variability in blue whale diving behavior. 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). 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 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 (3.1-6.2 mi) of the pile driving site, with declines at 
up to 20-30 km (12.4-18.6 mi) of the pile driving site documented in 
some cases. Similar results demonstrating the long-distance 
displacement of harbor porpoises (18-25 km (11.2-15.5 mi)) and harbor 
seals (up to 40 km (25 mi)) 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 SouthCoast 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 of Massachusetts. However, we do not 
anticipate any greater severity of

[[Page 53739]]

response due to harbor porpoise and harbor seal habitat use off of 
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 of Massachusetts, harbor porpoises are transient (with higher 
abundances in winter when foundation installation would not occur) and 
a 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 
(2.1-5.9 mi) away while showing no such reaction to the same signal 
when the signal was 118 km (73 mi) 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 km (1.2 mi) from shore) and are low-frequency hearing 
specialists. The LFA sonar source was placed within the gray whale 
migratory corridor (approximately 2 km (1.2 mi) offshore) and offshore 
of most, but not all, migrating whales (approximately 4 km (2.5 mi) 
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 SPLrms and 178 dBrms, 
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 dBrms demonstrated 
avoidance levels at ranges of +1 km (+0.6 mi). 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 study in the 
Bahamas, 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 
(12.4 mi) from the area (Boyd et al., 2008; Southall et al., 2009; 
Tyack et al., 2011). SouthCoast does not anticipate and NMFS is not 
proposing to authorize take of beaked whales and, moreover, the sounds 
produced by SouthCoast do not have signal characteristics similar to 
predators. Therefore, we would not expect such extreme reactions to 
occur for similar species.
    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). 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 stationary 
pile driving (which they can sense is stationary and predictable) or 
significantly lower-level HRG surveys unless they are within the area 
ensonified above behavioral harassment thresholds at the moment the 
source is turned on (Watkins, 1986; Falcone et al., 2017). A flight 
response may also be possible in response to UXO/MEC detonation. 
However, detonations would be restricted to one per day and a maximum 
of 10 over 5 years, thus, there would be limited opportunities for 
flight response to be elicited as a result of detonation noise. The 
proposed mitigation and monitoring would result in any animals being 
far from the detonation location (i.e., the clearance zones vary by 
hearing group and charge weight, but all zones are sized to ensure that 
marine mammals are beyond the area where PTS could occur prior to 
detonation) and any flight response would be spatially and temporally 
limited.

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

[[Page 53740]]

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 vessel 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 any 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 feeding (e.g., bubble nets or sediment plumes), or 
changes in dive behavior. As for other types of behavioral response, 
the frequency, duration, and temporal pattern of signal presentation as 
well as differences in species sensitivity are likely contributing 
factors to differences in response in any given circumstance (e.g., 
Croll et al., 2001; Nowacek et al.; 2004; Madsen et al., 2006; Yazvenko 
et al., 2007; 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., 2018a; 
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 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 (4.3-8.1 mi), following a 
phase-in of sound intensity and full array exposures at 1-13 km (0.6-
8.1 mi) (Madsen et al., 2006; 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 six percent lower during exposure than control periods 
(Miller et al., 2009). Miller et al. (2009) noted that more data are 
required to understand whether the differences were due to exposure or 
natural variation in sperm whale behavior.
    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 SouthCoast's activities at least partially overlaps 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., 2019b).
    Southall et al. (2011) found that blue whales had a different 
response to sonar exposure depending on behavioral state, which was 
more pronounced when whales were in deep feeding/travel modes than when 
engaged in surface

[[Page 53741]]

feeding. Southall et al. (2023) conducted a controlled exposure 
experiment (CEE) study similar to Southall et al. (2011), but focused 
on fin whale behavioral responses to different sound sources including 
mid-frequency active sonar (MFAS), and pseudorandom noise (PRN) signals 
lacking tonal patterns but having frequency, duration, and source 
levels similar to sonar. In general, fewer fin whales (33 percent) 
displayed observable behavioral responses to similar noise stimuli 
compared to blue whales (66 percent), and fin whale responses were less 
dependent on the behavioral state of the whale at the time of exposure 
and more closely associated with the received level (i.e., loudness) of 
the signal. Similar to blue whales, some fin whales responded to the 
sound exposure by lunge feeding and deep diving, particularly at higher 
received levels, and returned to baseline behaviors (i.e., as observed 
prior to sound exposure) relatively quickly following noise exposure. 
Southall et al. (2023) found no evidence that noise exposure 
compromised fin whale foraging success, in contrast with observations 
of noise-exposed foraging blue whales by Friedlander et al. (2016). The 
baseline acoustic environment appeared to influence the degree of fin 
whale behavioral responses. The five fin whales that did present 
observable behavioral responses did so to a greater extent when exposed 
to PRN than MFAS. Southall et al. (2023) conducted the CEE in fin whale 
habitat that overlaps with an area in southern California frequently 
used for military sonar training exercises, thus, whales may be more 
familiar with sonar signals than PRN, a novel stimulus. The 
observations by Southall et al. (2023) underscore the importance of 
considering an animal's exposure history when evaluating behavioral 
responses to particular noise stimuli.
    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 
mPa, 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. Here, 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. Seasonal restrictions on pile driving and UXO/MEC detonations 
would limit temporal and spatial co-occurrence of these activities and 
foraging North Atlantic right whales (and other marine mammal species) 
in southern New England, thereby minimizing disturbance during times of 
year when prey are most abundant.
    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.

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)'s 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, 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-

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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 
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

[[Page 53743]]

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 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 (1.9 mi) to over 9 km (5.6 mi) 
(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 vessel noise, source 
levels were lower than expected compared to observed source level 
changes with increased 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 (e.g., during 
vibratory pile driving, a continuous acoustic source) and concentrated 
support vessel operation. However, pile driving is an intermittent 
sound and would not be continuous throughout the day.
Habituation and Sensitization
    Habituation can occur when an animal's response to a stimulus wanes 
with repeated exposure, usually in the absence of unpleasant associated 
events (Wartzok et al., 2003). Animals are most likely to habituate to 
sounds that are predictable and unvarying. It is important to note that 
habituation is appropriately considered as a ``progressive reduction in 
response to stimuli that are perceived as neither aversive nor 
beneficial,'' rather than as, more generally, moderation in response to 
human disturbance having a neutral or positive outcome (Bejder et al., 
2009). The opposite process is sensitization, when an unpleasant 
experience leads to subsequent responses, often in the form of 
avoidance, at a lower level of exposure. Both habituation and 
sensitization require an ongoing learning process. As noted, behavioral 
state may affect the type of response. For example, animals that are 
resting may show greater behavioral change in response to disturbing 
sound levels than animals that are highly motivated to remain in an 
area for feeding (Richardson et al., 1995; U.S. National Research 
Council (NRC), 2003; Wartzok et al., 2003; Southall et al., 2019b). 
Controlled experiments with captive marine mammals have shown 
pronounced behavioral reactions, including avoidance of loud sound 
sources (e.g., Ridgway et al., 1997; Finneran et al., 2003; Houser et 
al. (2013a); Houser et al., 2013b; Kastelein

[[Page 53744]]

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 and Mench, 
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 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, vessel 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

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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 SouthCoast (e.g., pile 
driving) do not inherently have the potential to result in marine 
mammal strandings. While vessel strikes could kill or injure a marine 
mammal (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 for 
authorization from any specified activities.
    Of the strandings documented to date worldwide, NMFS is not aware 
of any being attributed to pile driving or the types of HRG equipment 
proposed for use during SouthCoast's surveys. Recently, there has been 
heightened interest in HRG surveys relative to 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 
SouthCoast. 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 200 m (656.2 ft) (such as those associated with 
the project), while zones for military mid-frequency active sonar or 
seismic airgun surveys typically extend for several kilometers ranging 
up to 10s of kilometers. 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. 
NMFS has performed a thorough review of a report submitted by Rand 
(2023) that includes measurements of the Geo-Marine Geo-Source 400 
sparker and suggests that NMFS is assuming lower source and received 
levels than is appropriate in its assessments of HRG impacts. NMFS has 
determined that the values in this proposed rule are appropriate, based 
on the model methodology (i.e., the assumed source level propagated 
using spherical spreading) here predicting a peak level 3 dB louder 
than the maximum measured peak level at the closest measurement range 
in Rand (2023).
    Also of note, in an assessment of monitoring reports for HRG 
surveys received from 2021 through 2023, as compared to the takes of 
marine mammals authorized, an average of fewer than 15 percent have 
been detected within harassment zones, with no more than 27 percent for 
any species (common dolphins) and 20 percent or less for all other 
species. The most common behavioral change observed while the HRG sound 
source was active was ``change direction'' (i.e. a potential behavioral 
reaction) though detections of ``no behavioral change'' occurred at 
least twice as many times as ``change direction.''

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

[[Page 53746]]

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 one day 
and not recurring on subsequent days is not considered particularly 
severe unless it could directly affect reproduction or survival 
(Southall et al., 2007). It is important to note the difference between 
behavioral reactions lasting or recurring over multiple days and 
anthropogenic activities lasting or recurring over multiple days. For 
example, just because certain activities last for multiple days does 
not necessarily mean that individual animals will be either exposed to 
those activity-related stressors (i.e., pile driving) 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 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

[[Page 53747]]

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).
    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). 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 SouthCoast'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 one second, no 
behavioral impacts below the TTS threshold are anticipated considering 
that SouthCoast would not detonate more than one UXO/MEC per day and 
only ten 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 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

[[Page 53748]]

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 will result from 
any UXO/MEC detonation that SouthCoast 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. 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). 
Some baleen whales seem generally unresponsive to vessel sound, making 
them more susceptible to vessel collisions (Nowacek et al., 2004). 
Marine mammal responses to vessels may include avoidance and changes in 
dive pattern (NRC, 2003). Wounds resulting from vessel 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).
    An examination of all known vessel 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 (15 mph).
    Jensen and Silber (2003) detailed 292 records of known or probable 
vessel 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 
(2.3 to 59 mph). The majority (79 percent) of these strikes occurred at 
speeds of 13 knots (15 mph) or greater. The average speed that resulted 
in serious injury or death was 18.6 knots (21.4 mph). 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 (11.5 to 16 mph), and 
exceeded 90 percent at 17 knots (20 mph). 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 (9.9 and 17 mph). The chances of a lethal injury 
decline from approximately 80 percent at 15 knots (17 mph) to 
approximately 20 percent at 8.6 knots (10 mph). At speeds below 11.8 
knots (13.5 mph), the chances of lethal injury drop below 50 percent, 
while the probability asymptotically increases toward 100 percent above 
15 knots (17 mph).
    The Jensen and Silber (2003) report notes that the Large Whale Ship 
Strike Database represents a minimum number of collisions, because the 
vast majority go undetected or unreported. In contrast, SouthCoast's 
personnel are likely to detect any strike that does occur because of 
the required personnel training and lookouts, along with the inclusion 
of PSOs as described in the Proposed Mitigation section), and they are 
required to report all ship strikes involving marine mammals.
    There are no known vessel strikes of marine mammals by any offshore 
wind

[[Page 53749]]

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 SouthCoast, NMFS believes 
that a vessel strike is not likely to occur.

Potential Effects to Marine Mammal Habitat

    SouthCoast'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 with a 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 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

[[Page 53750]]

re 1[mu]Pa Peak; cod: 140-161 dB re 1 [mu]Pa Peak, particle motion 
between 51 x 10 and 62 x 104\4\ m/s\2\ peak) (Mueller-Blenkle et al., 
2010). The swimming speed of the sole increased significantly during 
the playback period compared to before and after playback of 
construction noise when compared to the playbacks of before and after 
construction. While not statistically significant, cod also displayed a 
similar reaction, yet results were not significant. Cod showed a 
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. 
Both species displayed indications of 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., 2013a).
    As described in the Proposed Mitigation section below, SouthCoast 
would utilize a sound attenuation device which would reduce potential 
for injury to marine mammal prey. Other fish that experience hearing 
loss as a result of exposure to explosions and impulsive sound sources 
may have a reduced ability to detect relevant sounds such as predators, 
prey, or social vocalizations. However, PTS has not been known to occur 
in fishes and any hearing loss in fish may be as temporary as the 
timeframe required to repair or replace the sensory cells that were 
damaged or destroyed (Popper et al., 2005; Popper et al., 2014; Smith 
et al., 2006). It is 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 the UXO/MEC detonation. The 
shock wave from an underwater explosion is lethal to fish at close 
range, causing massive organ and tissue damage and internal bleeding 
(Keevin and Hempen, 1997). At greater distance from the detonation 
point, the extent of mortality or injury depends on a number of factors 
including fish size, body shape, orientation, and species (Keevin and 
Hempen, 1997; Wright, 1982). 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 air guns) (Halvorsen et al., 2012b; Casper et 
al., 2013).
    Fish not killed or driven from a location by an explosion might 
change their behavior, feeding pattern, or distribution. Changes in 
behavior of fish have been observed as a result of sound produced by 
explosives, with effect intensified in areas of hard substrate (Wright, 
1982). Stunning from pressure waves could also temporarily immobilize 
fish, making them more susceptible to predation. The abundances of 
various fish (and invertebrates) near the detonation point for 
explosives could be altered for a few hours before animals from 
surrounding areas repopulate the area. However, these populations would 
likely be replenished as waters near the detonation point are mixed 
with adjacent waters.
    UXO/MEC detonations would be dispersed in space and time; 
therefore, repeated exposure of individual fishes are unlikely. 
Mortality and injury effects to fishes from explosives would be 
localized around the area of a given in-water explosion but only if 
individual fish and the explosive (and immediate pressure field) were 
co-located at the same time. Repeated exposure of individual fish to 
sound and energy from underwater explosions is not likely given fish 
movement patterns, especially schooling prey species. In addition, 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 impact pile driving source prior to any noise levels that 
may physically injure prey, and the use of the noise attenuation 
devices would reduce noise levels to the degree any mortality or injury 
of prey is also minimized. Use of bubble curtains, in addition to 
reducing impacts to marine mammals, for example, is a key mitigation 
measure in reducing injury and mortality of ESA-listed salmon on the 
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

[[Page 53751]]

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 
mammal 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 mPa\2\ and 400 Hz, 139 to 141 dB re 1 mPa\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 mPa\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 (Budelmann, 1992). 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.
    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 (0.6 mi) 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 more recent 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 (16.4 ft) or less from the airguns. Mortality one week after the 
airgun blast was significantly higher in the copepods placed 10 m (32.8 
ft) from the airgun but was not significantly different from the 
controls at a distance of 20 m (65.6 ft) 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 sublethal 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 (1,670-2,159 
ft), with zooplankton mortality observed at that range, Fields et al. 
(2019) reported an SEL of 186 dB at a range of 25 m (82 ft), with no 
reported mortality at that distance.
    The presence and operation of wind turbines (both the foundation 
and WTG) 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 OSP foundations cause turbulent current 
wakes, which impact circulation, stratification, mixing, turbidity, and 
sediment resuspension (Daewel et al., 2022). Impacts from the presence 
of structures and/or operation of wind turbine generators are generally 
likely to result in certain oceanographic

[[Page 53752]]

effects, such as perturbation of zooplankton aggregation mechanisms 
through changes to the strength of tidal currents and associated 
fronts, stratification, the degree of mixing, and primary production in 
the water column, and these effects may alter the production, 
distribution, and/or availability of marine mammal zooplankton prey 
(Chen et al., 2021; Chen et al., 2024, Johnson et al., 2021, 
Christiansen et al., 2022, Dorrell et al., 2022).
    Assessing the ecosystem impacts of offshore wind development has a 
unique set of challenges, including minimizing uncertainties in the 
fundamental understanding of how existing physical and biological 
oceanography might be altered by the presence of a single offshore wind 
turbine, by an offshore wind farm, or by a region of adjacent offshore 
wind farms. Physical models can demonstrate, among many things, the 
extent to which and how a single or large number of operating offshore 
wind turbine(s) can alter atmospheric and hydrodynamic flow through 
interruptions of local winds that drive circulation processes and by 
creating turbulence in the water column surrounding the pile(s). For 
example, Chen et al., 2024 found that regardless of variations in wind 
intensity and direction, the downwind wake caused by WTGs, as modeled 
from a wind farm simulation in a lease area located to the west of the 
SouthCoast lease area, could consistently produce and enhance offshore 
water transport of zooplankton (in this case scallop larvae), 
particularly around the 40 to 50-m isobaths.
    However, many physical and biological processes are influenced by 
cross-scale phenomena (e.g., aggregation of dense zooplankton patches), 
necessitating construction of more complex models that tolerate varying 
degrees of uncertainty. Thus, determining the impacts of offshore wind 
operations on not only physical processes but trophic connections from 
phytoplankton to marine mammals and ultimately the ecosystem will 
require significant data collection, monitoring, modeling, and research 
effort. Given the limited state of understanding of the entire system 
in southern New England and the changing oceanography and ecology, 
identification of substantial impacts on zooplankton, and specifically 
on right whale prey, that may result from wind energy development in 
the Nantucket Shoals region is difficult to assess ((National Academy 
of Sciences (NAS), 2023.
    SouthCoast intends to install up to 147 WTGs, up to 85 of which 
would be operational following completion of Project 1 and the 
remainder operational following installation of Project 2. SouthCoast 
may commission turbines in batches (i.e., not all foundations and WTGs 
need to be installed per Project before becoming operational). Based on 
SouthCoast's current schedule (Table 1), commissioning could begin in 
early 2029, assuming foundations were installed the previous year, 
thus, it is possible that any influence of operating turbines on local 
physical and/or biological processes may be observable at that time, 
depending on latency of effects. Given the proposed sequencing, NMFS 
anticipates the turbines closest to Nantucket Shoals would be 
commissioned first. As described above, there is scientific uncertainty 
around the scale of oceanographic impacts (meters to kilometers) 
associated with the presence of foundation structures (e.g., monopile, 
piled jacket) in the water, as well as operation of the WTGs. Generally 
speaking and depending on the extent, impacts on prey could influence 
the distribution of marine mammals in within and among foraging 
habitats, potentially necessitating additional energy expenditure to 
find and capture prey, which could lead to fitness consequences. 
Although studies assessing the impacts of offshore wind development on 
marine mammals are limited and the results vary, the repopulation of 
some 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 
indicates that, in some cases, there is evidence that suitable habitat, 
including prey resources, exists within developed waters.
Reef Effects
    The presence of WTG and OSP 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 OSP 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 
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

[[Page 53753]]

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, which may affect marine mammal food 
sources such as forage fish and zooplankton.
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 Lease Area and ECCs. Indirect effects of 
explosives and unexploded ordnance to marine mammals via sediment 
disturbance is possible in the immediate vicinity of the ordnance but 
through the implementation of the mitigation, is it not anticipated 
marine mammals would be in the direct area of the explosive source. 
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 are 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 Lease Area and ECCs.
    Further, contamination of water is not anticipated. Degradation 
products of Royal Demolition Explosive are not toxic to marine 
organisms at realistic exposure levels (Rosen and Lotufo, 2010). 
Relatively low solubility of most explosives and their degradation 
products means that concentrations of these contaminants in the marine 
environment are relatively low and readily diluted. Furthermore, while 
explosives and their degradation products were detectable in marine 
sediment approximately 6-12 in (0.15-0.3 m) away from degrading 
ordnance, the concentrations of these compounds were not statistically 
distinguishable from background beyond 3-6 ft (1-2 m) from the 
degrading ordnance.
    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 SouthCoast for the project, including ships and 
other marine vessels, aircrafts, and other implements, are also 
potential sources of by-products (e.g., hydrocarbons, particulate 
matter, heavy metals). SouthCoast would be required to properly 
maintain all equipment in accordance with applicable legal requirements 
such that 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 holistic soundscape, encompassing all of 
the biotic and abiotic sound in a particular location and time, as 
perceived by an individual. Animals produce sound for and 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) comprise the natural contributions to the total soundscape. 
These acoustic conditions, termed acoustic habitat, are one attribute 
of an animal's total habitat.
    Anthropogenic sound is another facet of the soundscape that 
influences the overall acoustic habitat. This may include incidental 
contributions from sources such as vessels or sounds intentionally 
introduced to the marine environment for data acquisition purposes 
(e.g., use of high-resolution geophysical surveys), detonations for 
munitions disposal or coastal constructions, sonar for Navy training 
and testing purposes, or pile driving/hammering for 
construction.projects. 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 their acoustic habitat, animals may alter their 
communications signals (thereby potentially expending additional 
energy) or miss acoustic cues (either conspecific or adventitious). 
Problems arising from a failure to detect cues are more likely to occur 
when noise stimuli are chronic and overlap with biologically relevant 
cues used for communication, orientation, and predator/prey detection 
(Francis and Barber, 2013). For more detail on these concepts see, 
e.g., Barber et al., 2009; Pijanowski et al., 2011; Francis and Barber, 
2013; Lillis et al., 2014.
    Communication space describes the area over which an animal's 
acoustic signal travels and is audible to the intended receiver 
(Brenowitz, 1982; Janik, 2000; Clark et al., 2009; Havlick et al., 
2022). The extent of this area depends on the temporal and spectral 
structure of the signal, the characteristics of the environment, and 
the receiver's ability to detect (the detection threshold) and 
discriminate the signal from background noise (Wiley and Richards, 
1978; Clark et al., 2009; Havlick et al., 2022). Large communication 
spaces are created by acoustic signals that propagate over long 
distances relative to the distribution of conspecifics, as exemplified 
by low-frequency baleen whale vocalizations (McGregor and Krebs, 1984; 
Morton, 1986; Janik, 2000). Conversely, both natural and anthropogenic 
noise may reduce communication space by increasing background noise, 
leading to a generalized contraction of the range over which animals 
would be able to detect signals of biological importance, including 
eavesdropping on predators and prey (Barber et al., 2009). Any 
reduction in the communication space, due to increased background noise 
resulting in masking, may therefore have detrimental effects on the 
ability of animals to obtain important social and environmental 
information. 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 of acoustic 
signal interference mediated through changes in the ultimate survival 
and reproductive success of individuals are difficult to study, and 
particularly in the marine environment. However, it is increasingly 
well documented that aquatic species rely on qualities of natural 
acoustic habitats. For example, researchers have quantified 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., damselfish; Simpson et al., 2016; larval 
Atlantic cod, Nedelec et al., 2015a; embryonic sea hare, Nedelec et 
al., 2015a) following noise exposure.
    Although this proposed rulemaking primarily covers the noise 
produced from construction activities relevant to the SouthCoast 
offshore wind facility, operational noise was a consideration in NMFS' 
analysis of the project, as some, and potentially all, turbines would

[[Page 53754]]

become operational within the effective period of the rule (if issued). 
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 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 (164 ft) (Tougaard et al., 2020). Recent 
measurements of operational sound generated from wind turbines (direct 
drive, 6 MW, jacket foundations) at Block Island wind farm (BIWF) 
indicate average broadband levels of 119 dB at 50 m (164 ft) 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). In addition, Madsen et al. (2006) 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.
    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 parameters) performed by Tougaard et al. (2020) yields 
similar results for a hypothetical 10 MW WTG.
    Recently, Holme et al. (2023) cautioned that Tougaard et al. (2020) 
and St[ouml]ber and Thomsen (2021) extrapolated levels for larger 
turbines should be interpreted with caution since both studies relied 
on data from smaller turbines (0.45 to 6.15 MW) collected over a 
variety of environmental conditions. They demonstrated that the model 
presented in Tougaard et al. (2020) tends to potentially overestimate 
levels (up to approximately 8 dB) measured to those in the field, 
especially with measurements closer to the turbine for larger turbines. 
Holme et al. (2023) measured operational noise from larger turbines 
(6.3 and 8.3 MW) associated with three wind farms in Europe and found 
no relationship between turbine activity (power production, which is 
proportional to the blade's revolutions per minute) and noise level, 
though it was noted that this missing relationship may have been masked 
by the area's relatively high ambient noise sound levels. Sound levels 
(RMS) of a 6.3 MW direct-drive turbine were measured to be 117.3 dB at 
a distance of 70 m (229.7 ft). However, measurements from 8.3 MW 
turbines were inconclusive as turbine noise was deemed to have been 
largely masked by ambient noise.
    Finally, operational turbine measurements are available from the 
Coastal Virginia Offshore Wind (CVOW) pilot pile project, where two 7.8 
m-monopile WTGs were installed (HDR, 2023). Compared to BIWF, levels at 
CVOW were higher (10-30 dB) below 120 Hz, believed to be caused by the 
vibrations associated with the monopile structure, while above 120 Hz 
levels were consistent among the two wind farms.
    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 SouthCoast to measure operational noise levels.

Estimated Take

    This section provides an estimate of the number of incidental takes 
that may be authorized through the proposed 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.
    Authorized takes would be primarily by Level B harassment, as use 
of the acoustic sources (i.e., impact and vibratory pile driving, site 
characterization surveys, and UXO/MEC detonations) has the potential to 
result in disruption of marine mammal behavioral patterns due to 
exposure to elevated noise levels. Impacts such as masking and TTS can 
contribute to behavioral disturbances. There is also some potential for 
auditory injury (Level A harassment) to occur in select marine mammal 
species incidental to the specified activities (i.e., impact pile 
driving and UXO/MEC detonations). The required mitigation and 
monitoring measures, the majority of which are not considered in the 
estimated take analysis, are expected to reduce the extent of the 
taking to the lowest level practicable.
    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 in 
this proposed rule, when implemented, are expected to minimize the 
potential for take by mortality or serious injury such that the 
probability for take is discountable. No other activities have the 
potential to result in mortality or serious injury, and no serious 
injury is anticipated or proposed for authorization through this 
rulemaking.
    Generally speaking, we estimate take by considering: (1) thresholds 
above which the best scientific information available indicates marine 
mammals will be behaviorally harassed or incur some degree of permanent 
hearing impairment or non-auditory injury; (2) the area or volume of 
water that will be ensonified above these levels in a day; (3) the 
density or occurrence of marine mammals within these ensonified areas; 
and, (4) 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

[[Page 53755]]

monitoring results or average group size).
    Below, we describe NMFS' acoustic and non-auditory injury 
thresholds, acoustic and exposure modeling methodologies, marine mammal 
density calculation methodology, occurrence information, and the 
modeling and methodologies applied to estimate incidental take for each 
specified activity likely to result in take by harassment.

Marine Mammal Acoustic Thresholds

    NMFS recommends the use of acoustic thresholds that identify the 
received level of underwater sound above which exposed marine mammals 
are likely to be behaviorally harassed (equated to Level B harassment) 
or to incur PTS of some degree (equated to Level A harassment). 
Thresholds have also been developed to identify the levels above which 
animals may incur different types of tissue damage (non-acoustic Level 
A harassment or mortality) from exposure to pressure waves from 
explosive detonation. A summary of all NMFS' thresholds can be found at 
(https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance).
Level B Harassment
    Though significantly driven by received level, the onset of 
behavioral disturbance from anthropogenic noise exposure is also 
informed to varying degrees by other factors related to the source or 
exposure context (e.g., frequency, predictability, duty cycle, duration 
of the exposure, signal-to-noise ratio, distance to the source, ambient 
noise, and the receiving animals (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 the best scientific information 
available 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 SPLrms160 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 
behavior patterns that would not otherwise occur.
Level A Harassment
    NMFS' Technical Guidance for Assessing the Effects of Anthropogenic 
Sound on Marine Mammal Hearing (Version 2.0) (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, SouthCoast'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.

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

Explosive Source
    Based on the best scientific information available, NMFS uses the 
acoustic and pressure thresholds indicated in tables 8 and 9 to predict 
the onset of behavioral harassment, TTS, PTS, non-auditory injury, and 
mortality incidental to explosive detonations. Given SouthCoast would 
be limited to detonating one UXO/MEC per day, the TTS threshold is used 
to estimate the potential for Level B (behavioral) harassment (i.e., 
individuals exposed above the TTS threshold may also be harassed by 
behavioral disruption, but we do not anticipate any impacts from 
exposure to UXO/MEC detonation

[[Page 53756]]

below the TTS threshold would constitute behavioral harassment).

        Table 8--PTS Onset, TTS Onset, for Underwater Explosives
                              [NMFS, 2018]
------------------------------------------------------------------------
                                                           Impulsive
                                                      thresholds for TTS
          Hearing group              PTS impulsive      and behavioral
                                      thresholds      disturbance from a
                                                       single detonation
------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans....  Cell 1: Lpk,flat:   Cell 2: Lpk,flat:
                                   219 dB;             213 dB;
                                   LE,LF,24h: 183 dB.  LE,LF,24h: 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:
                                   202 dB;             Lpk,flat: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) 
(table 9). These criteria have been developed by the U.S. Navy (DoN 
(U.S. Department of the Navy) 2017a) and are based on the mass of the 
animal and the depth at which it is present in the water column. 
Equations predicting the onset of the associated potential effects are 
included below (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.
Modified Goertner Equations for severe and slight lung injury (pascal-second):
Equation 1: 103M\1/3\(1 + D/10.1)\1/6\ Pa-s.
Equation 2: 47.5M\1/3\(1 + D/10.1)\1/6\ Pa-s.
M animal (adult and/or calf/pup) mass (kg) (Table C.9 in DoN, 2017).
D animal depth (meters).

Modeling and Take Estimation

    SouthCoast estimated density-based exposures in two separate ways, 
depending on the activity. To assess the potential for Level A 
harassment and Level B harassment resulting from exposure to the 
underwater sound fields produced during impact and vibratory pile 
driving, sophisticated sound and animal movement modeling was conducted 
to account for movement and behavior of marine mammals. For HRG surveys 
and UXO/MEC detonations, SouthCoast estimated the number of takes by 
Level B harassment using a simplified ``static'' method wherein the 
take estimates are the product of density, area of water ensonified 
above the NMFS defined threshold (e.g., unweighted 160 dB 
SPLrms) levels, and number of activity days (assuming a 
maximum of one UXO/MEC detonation per day). For some species, 
observational data from PSOs aboard HRG survey vessels or group size 
indicated that the density-based take estimates may be insufficient to 
account for the number of individuals of a species that may be 
encountered during the planned activities; thus, adjustments were made 
to the density-based estimates.
    The assumptions and methodologies used to estimate take, in 
consideration of acoustic thresholds and appropriate marine mammal 
density and occurrence information, are described in activity-specific 
subsections below (i.e.,WTG and OSP foundation installation, HRG 
surveys, and UXO/MEC detonation). Resulting distances to threshold 
isopleths, densities used, activity-specific exposure estimates (as 
relevant to the analysis), and take estimates can be found in each 
activity subsection below. At the end of this section, we present the 
total annual and 5-year take estimates that NMFS proposes to authorize.
Marine Mammal Density and Occurrence
    In this section, we provide information about marine mammal 
presence, density, or group dynamics that will inform the take 
calculations for all activities. Depending on the stock and as 
described in the take estimation section for each activity, take 
estimates may be based on the Roberts et al. (2023) density estimates, 
marine mammal monitoring results from HRG surveys, or average group 
sizes. The density and occurrence information resulting in the highest 
take estimate

[[Page 53757]]

was considered in subsequent analyses, and the explanation and results 
for each activity are described in the specific activity sub-sections.
    Habitat-based density models produced by the Duke University Marine 
Geospatial Ecology Laboratory and the Marine-life Data and Analysis 
Team, based on the best available marine mammal data obtained in a 
collaboration between Duke University, the Northeast Regional Planning 
Body, the University of North Carolina Wilmington, the Virginia 
Aquarium and Marine Science Center, and NOAA (Roberts et al., 2016a, 
2016b, 2017, 2018, 2020, 2021a, 2021b, 2023), represent the best 
available scientific information regarding marine mammal densities in 
and surrounding the Lease Area and along ECCs. Density data are 
subdivided into five separate raster data layers for each species, 
including: Abundance (density), 95 percent Confidence Interval of 
Abundance, 5 percent Confidence Interval of Abundance, Standard Error 
of Abundance, and Coefficient of Variation of Abundance.
    Modifications to the densities used were necessary for some 
species. The estimated monthly density of seals provided in Roberts et 
al. (2016; 2023) includes all seal species present in the region as a 
single guild. To split the resulting ``seal'' density estimate by 
species, SouthCoast multiplied the estimate by the proportion of each 
species observed by PSOs during SouthCoast's 2020-2021 site 
characterization surveys (Milne, 2021; 2022). The proportions used were 
231/246 (0.939) for gray seals and 15/246 (0.061) for harbor seals. The 
``seal'' density provided by Roberts et al. (2016; 2023) was then 
multiplied by these proportions to get the species specific densities. 
While the Roberts et al. (2016; 2023) seals guild includes all phocid 
seals, as described in the Descriptions of Marine Mammals in the 
Specified Geographical Region section, harp seal occurrence is 
considered rare and unexpected in SNE. Given this, harp seals were not 
included when splitting the seal guild density and SouthCoast did not 
request take for this species. Monthly densities were unavailable for 
pilot whales, so SouthCoast applied the annual mean density to estimate 
take. As described in the Marine Mammal section, species' distributions 
indicate that the only species of pilot whale expected to occur in SNE 
is the long-finned pilot whale; therefore, the densities provided in 
Roberts et al. (2016, 2023) are attributed to this species (and not 
short-finned pilot whales). Similarly, distribution data for bottlenose 
dolphins stocks indicate that the only stock likely to occur in SNE is 
the Western North Atlantic offshore stock, thus all Robert et al. 
(2016, 2023) densities are attributed to this stock. Below, we describe 
observational data from monitoring reports and average group size 
information, both of which are appropriate to inform take estimates for 
certain activities or species in lieu of density estimates.
    For some species and activities, observational data from Protected 
Species Observers (PSOs) aboard HRG and geotechnical (GT) survey 
vessels indicate that the density-based exposure estimates may be 
insufficient to account for the number of individuals of a species that 
may be encountered during the planned activities. PSO data from 
geophysical and geotechnical surveys conducted in the area surrounding 
the Lease Area and ECCs from April 2020 through December 2021 (RPS, 
2021) were analyzed to determine the average number of individuals of 
each species observed per vessel day. For each species, the total 
number of individuals observed (including the``proportion of 
unidentified individuals'') was divided by the number of vessel days 
during which observations were conducted in 2020-2021 HRG surveys (555 
survey days) to calculate the number of individuals observed per vessel 
day, as shown in the final columns of Table 7 in the SouthCoast ITA 
application.
    For other less-common species, the predicted densities from Roberts 
et al. (2016; 2023) are very low and the resulting density-based 
exposure estimate is less than a single animal or a typical group size 
for the species. In such cases, the mean group size was considered as 
an alternative to the density-based or PSO data-based take estimates to 
account for potential impacts on a group during an activity. Mean group 
sizes for each species were calculated from recent aerial and/or 
vessel-based surveys, as shown in table 10. Additional detail regarding 
the density and occurrence as well as the methodology used to estimate 
take for specific activities is included in the activity-specific 
subsections below.

                    Table 10--Mean Group Sizes of Species That May Occur in the Project Area
----------------------------------------------------------------------------------------------------------------
                                                                          Mean group
                Species                   Individuals      Sightings         size          Information source
----------------------------------------------------------------------------------------------------------------
North Atlantic right whale *..........             145              60             2.4  Kraus et al. (2016).
Blue whale *..........................               3               3             1.0  Palka et al. (2017).
Fin whale *...........................             155              86             1.8  Kraus et al. (2016).
Humpback whale........................             160              82             2.0  Kraus et al. (2016).
Minke whale...........................             103              83             1.2  Kraus et al. (2016).
Sei whale *...........................              41              25             1.6  Kraus et al. (2016).
Sperm whale *.........................             208             138             1.5  Palka et al. (2017).
Atlantic spotted dolphin..............           1,335              46            29.0  Palka et al. (2017).
Atlantic white-sided dolphin..........             223               8            27.9  Kraus et al. (2016).
Bottlenose dolphin....................             259              33             7.8  Kraus et al. (2016).
Common dolphin........................           2,896              83            34.9  Kraus et al. (2016).
Pilot whales..........................             117              14             8.4  Kraus et al. (2016).
Risso's dolphin.......................           1,215             224             5.4  Palka et al. (2017).
Harbor porpoise.......................             121              45             2.7  Kraus et al. (2016).
Seals.................................             201             144             1.4  Palka et al. (2017).
(harbor and gray).....................
----------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.

    The estimated exposure and take tables for each activity present 
the density-based exposure estimates, PSO-date derived take estimate, 
and mean group size for each species. The number of species-specific 
takes by Level B harassment that is proposed for authorization is based 
on the largest of these three values. Although animal

[[Page 53758]]

exposure modeling resulted in Level A harassment exposure estimates for 
other species, NMFS is not proposing to authorize Level A harassment 
take for any species other than fin whales, harbor porpoises, and 
harbor and gray seals. The numbers of takes by Level A harassment 
proposed for authorization for these species are based strictly on 
density-based exposure modeling results (i.e., not on PSO-data derived 
estimates or group size).

WTG and OSP Foundation Installation

    Here, for WTG and OSP monopile and pin-piled jacket foundation 
installation, we provide summary descriptions of the modeling 
methodology used to predict sound levels generated from the Project 
with respect to harassment thresholds and potential exposures using 
animal movement, the density and/or occurrence information used to 
support the take estimates for this activity, and the resulting 
acoustic and exposure ranges, exposures, and authorized takes.
    The predominant underwater noise associated with the construction 
of offshore components of the SouthCoast Project would result from 
impact and vibratory pile driving of the monopile and jacket 
foundations. SouthCoast employed JASCO Applied Sciences (USA) Inc. 
(JASCO) to conduct acoustic modeling to better understand sound fields 
produced during these activities (Limpert et al., 2024). 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 both impact and vibratory pile driving, JASCO conducted 
sophisticated source and propagation modeling (as described below). 
JASCO also conducted animal movement modeling to estimate the potential 
for marine mammal harassment incidental to pile driving. JASCO 
estimated species-specific exposure probabilities by considering the 
range- and depth-dependent sound fields in relation to animal movement 
in simulated representative construction scenarios. More details on 
these acoustic source modeling, propagation modeling and exposure 
modeling methods are described below and can be found in Limpert et al. 
(2024).
Pile Driving Acoustic Source Modeling
    To model the sound emissions from the piles, the force of the pile 
driving hammers had to be modeled first. JASCO used the GRL, Inc. Wave 
Equation Analysis of Pile Driving wave equation model (GRLWEAP) (Pile 
Dynamics, 2010) in conjunction with JASCO's Pile Driving Source Model 
(PDSM), a physical model of pile vibration and near-field sound 
radiation (MacGillivray, 2014), to predict source levels associated 
with impact and vibratory pile driving activities. Forcing functions, 
representing the force of the impact or vibratory hammer at the top of 
each 9/16-m monopile and 4.5-m jacket foundation pile, were computed 
using the GRLWEAP 2010 wave equation model (GRLWEAP) (Pile Dynamics, 
2010), which includes a large database of simulated impact and 
vibratory hammers. The GRLWEAP model assumed direct contact between the 
representative impact and vibratory hammers, helmets, and piles (i.e., 
no cushioning material, which provides a more conservative estimate). 
For monopile and jacket foundations, the piles were assumed to be 
vertical and driven to a penetration depth of 35 m (115 ft) and 60 m 
(197 ft), respectively. Modeling assumed jacket foundation piles were 
either pre- and post-piled. As indicated in the Description of 
Specified Activities section, pre-piling means that the jacket 
structure will be set on pre-installed piles, as would be the case for 
SouthCoast's WTG foundations (if jacket foundations are used for WTGs). 
OSP foundations would be post-piled (using only impact pile driving), 
meaning that the jacket structure is placed on the seafloor and piles 
would be subsequently driven through guides at the base of each leg. 
These jacket foundations (which are separate from the pin piles on 
which they sit) will also radiate sound as the piles are driven. To 
account for the additional sound (beyond impact hammering of the OSP 
pin piles) radiating from the jacket structure, a 2-dB increase in 
received levels was included in the propagation calculations for OSP 
post-piling installations, based on a recommendation from Bellman et 
al. (2020).
    Modeling the forcing function for vibratory pile driving required 
slightly different considerations than for impact pile driving given 
differences in the way each hammer type interacts with a pile, although 
the models used are the same for installation methods. Piles deform 
when driven with impact hammers, creating a bulge that travels down the 
pile and radiates sound into the surrounding air, water, and seabed. 
During the vibratory pile driving stage, piles are driven into the 
substrate due to longitudinal vibration motion at the hammer's 
operational frequency and corresponding amplitude, which causes the 
soil to liquefy, allowing the pile to penetrate into the seabed. Using 
GRLWEAP, one-second long vibratory forcing functions were computed for 
the 9/16-m monopile and 4.5-m jacket foundations, assuming the use of 
32 clamps with total weight of 2102.4 kN for the monopile and 4 clamps 
with total weight of 213.56 kN for the jacket piles, connecting the 
hammer to the piles. Non-linearities were introduced to the vibratory 
forcing functions based on the decay rate observed in data measured 
during vibratory pile driving of smaller diameter piles (Quijano et 
al., 2017). Key modeling assumptions can be found in Table B-1 in 
Appendix B of Limpert et al. (2024). Please see Figures 12 and 13 in 
Section 4.1.1 of Limpert et al. (2024), for impact pile driving forcing 
functions, and Figures 18 and 19 in section 4.1.2 for vibratory pile 
driving forcing functions.
    Both the impact and vibratory pile driving forcing functions 
computed using the GRLWEAP model were used then as inputs to the PDSM 
model to compute the resulting pile vibrations. 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 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. Piles were modeled assuming vertical installation using a 
finite-difference structural model of pile vibration based on thin-
shell theory. The sound radiating from the pile itself was simulated 
using a vertical array of discrete point sources. This model is used to 
estimate the energy distribution per frequency (source spectrum) at a 
close distance from the source (10 m (32.8 ft)). Please see Appendix E 
in Limpert et al. (2024), for a more detailed description.
    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 
(i.e., when the pile is approaching full installation depth) where the 
greatest resistance is encountered (Betke, 2008). Rather than modeling 
increasing hammer energy with increasing penetration depth, SouthCoast 
assumed that maximum hammer energy would be used throughout the entire 
installation of

[[Page 53759]]

monopiles and pin piles (tables 11 and 12). This is a conservative 
assumption, given the project area includes a predominantly sandy 
bottom habitat, which is a softer sediment (see Specified Geographical 
Area section) that would require less than the maximum hammer energy to 
penetrate.
    Representative hammering schedules for impact installation are 
shown in table 11 and for installations requiring vibratory followed by 
impact installation in table 12. For impact installation of 9/16-m WTG 
monopiles, 7,000 total hammer strikes were assumed, using the maximum 
hammer energy (6,600 kJ). The smaller 4.5-m pin piles for the WTG and 
OSP jacket foundations were assumed to require 4,000 total strikes 
using the maximum hammer energy (3,500 kJ). Modeling vibratory and 
subsequent impact installation of 9/16-m monopiles assumed 20 minutes 
of vibratory piling followed by 5,000 strikes of impact hammering. 
Installation of 4.5-m WTG piles using both vibratory and impact 
hammering methods assumed 90 minutes of vibratory pile driving followed 
by 2,667 impact hammer strikes.

     Table 11--Hammer Energy Schedules For Monopile and Jacket Foundations Installed With Impact Hammer Only
----------------------------------------------------------------------------------------------------------------
          WTG monopile foundations (9/16-m diameter)             WTG and OSP jacket foundations (4.5-m diameter)
----------------------------------------------------------------------------------------------------------------
                       Hammer: NNN 6600                                         Hammer: MHU 3500S
----------------------------------------------------------------------------------------------------------------
                                                     Pile                                              Pile
 Energy level (kilojoule, kJ)   Strike count     penetration      Energy level     Strike count     penetration
             \1\                                  depth (m)      (kilojoule, kJ)                       depth
----------------------------------------------------------------------------------------------------------------
6,600 \a\....................           2,000            0-10   3,500 \a\.......           1,333            0-20
6,600 \b\....................           2,000           11-21   3,500 \b\.......           1,333           21-41
6,600 \c\....................           3,000           22-35   3,500 \c\.......           1,334           41-60
                              ---------------------------------                  -------------------------------
    Total:...................           7,000              35      Total:.......           4,000              60
----------------------------------------------------------------------------------------------------------------
a, b, c--Modeling assumed application of the maximum hammer energy throughout the entire monopile installation.
  For ease of reference, JASCO used this notation to differentiate progressive stages of installation at the
  same hammer energy but at different penetration depths and number of hammer strikes.


                 Table 12--Hammer Energy Schedules For Monopile and Jacket Foundations Installed With Both Vibratory and Impact Hammers
--------------------------------------------------------------------------------------------------------------------------------------------------------
                      WTG monopile foundations (9/16-m diameter)                                    WTG jacket foundations (4.5-m diameter)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                       Hammers                                                                      Hammers
--------------------------------------------------------------------------------------------------------------------------------------------------------
                         Vibratory HXCV640 and Impact NNN6600                                        Vibratory SCV640 and Impact MHU 3500S
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                             Pile                                                               Pile
          Hammer type             Energy level     Strike     Duration    penetration    Hammer      Energy level     Strike     Duration    penetration
                                (kilojoule, kJ)     count     (minutes)    depth (m)      type     (kilojoule, kJ)     count     (minutes)    depth (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory.....................            3,500  ..........          20          0-10   Vibratory            3,500  ..........          90          0-20
Impact........................            6,600       2,000  ..........         11-21      Impact            6,000       1,333  ..........         21-41
                                                --------------------------------------                             -------------------------------------
                                                      3,000  ..........         22-35                                    1,334  ..........         42-60
                               -------------------------------------------------------------------------------------------------------------------------
    Total:....................  ...............       5,000          20            35  ..........  ...............       2,667          90            60
--------------------------------------------------------------------------------------------------------------------------------------------------------
a, b, c--Modeling assumed application of the maximum hammer energy throughout the entire monopile installation. For ease of reference, JASCO used this
  notation to differentiate progressive stages of installation at the same hammer energy but at different penetration depths and number of hammer
  strikes.


Table 13--Broadband SEL (dB re 1 [mu]Pa\2\[middot]s) per Modeled Energy Level at 10 m From a 9/16-m Monopile and
      4.5-m Pin Pile Installed Using a Impact Hammer at Two Representative Locations in the Lease Area \a\
----------------------------------------------------------------------------------------------------------------
                                                            Energy Level                     SEL
            Pile type                  Impact hammer      (kilojoule, kJ)  -------------------------------------
                                                                \a\              L01 \1\            L02 \1\
----------------------------------------------------------------------------------------------------------------
9/16-m Monopile..................  NNN6600.............          6,600 \a\              207.5              208.1
                                                                 6,600 \b\              206.2              206.9
                                                                 6,600 \c\              206.9              207.1
4.5-m Pin Pile...................  MHU 3500S...........              3,500              197.4              198.1
                                                                     3,500              198.5              198.7
                                                                     3,500              195.7              190.5
----------------------------------------------------------------------------------------------------------------
1--L01 and L02 are located in the southwest and northeast sections of the Lease Area, respectively. See Figure 2
  in Limpert et al. (2023) for a map of these locations.
a, b, c--Modeling assumed application of the maximum hammer energy throughout the entire monopile installation.
  For ease of reference, JASCO used this notation to differentiate progressive stages of installation at the
  same hammer energy but at different penetration depths and number of hammer strikes.


[[Page 53760]]


   Table 14--Broadband SEL (dB re 1 [mu]Pa\2\[middot]s) Per Duration of Vibratory Piling at 10 m From a 9/16-m
 Monopile and 4.5-m Pin Pile Installed Using Impact Hammering at Two Representative Locations in the Lease Area
                                                       \a\
----------------------------------------------------------------------------------------------------------------
                                                           Vibratory pile      SEL (dB re 1 [mu]Pa\2\[middot]s
              Pile type                Vibratory hammer   driving duration -------------------------------------
                                                               (min)               L01                L02
----------------------------------------------------------------------------------------------------------------
9/16-m Monopile.....................           TA-CV320                 20              214.8              213.5
4.5-m Pin Pile......................           HX-CV640                 90              193.3              190.3
----------------------------------------------------------------------------------------------------------------
a--L01 and L02 are located in the southwest and northeast sections of the Lease Area, respectively. See Figure 2
  in Limpert et al. (2023) for a map of these locations.
a, b, c--Modeling assumed application of the maximum hammer energy throughout the entire monopile installation.
  For ease of reference, JASCO used this notation to differentiate progressive stages of installation at the
  same hammer energy but at different penetration depths and number of hammer strikes.

    Beyond understanding pile driving source levels (estimated using 
forcing functions), there are additional factors to consider when 
determining the degree to which noise would be transmitted through the 
water column. Noise abatement systems (NAS) are often used to decrease 
the sound levels in the water near a source by inserting a local 
impedance change that acts as a barrier to sound transmission. 
Attenuation by impedance change can be achieved through a variety of 
technologies, including bubble curtains, evacuated sleeve systems 
(e.g., IHC-Noise Mitigation System (NMS)), encapsulated bubble systems 
(e.g., HydroSound Dampers (HSD)), or Helmholtz resonators (AdBm NMS). 
The effectiveness of each system is frequency dependent and may be 
influenced by local environmental conditions such as current and depth. 
SouthCoast would employ systems to attenuate noise during all pile 
driving of monopile and jacket foundations, including, at minimum, a 
double big bubble curtain (DBBC). Several recent studies summarizing 
the effectiveness of NAS have shown that broadband sound levels are 
likely to be reduced by anywhere from 7 to 17 dB, depending on the 
environment, pile size, and the size, configuration and number of 
systems used (Buehler et al., 2015; Bellmann et al., 2020). Hence, 
hypothetical broadband attenuation levels of 0 dB, 6 dB, 10 dB, 15 dB, 
and 20 dB were incorporated into acoustic modeling to gauge effects on 
the ranges to thresholds given these levels of attenuation. Although 
five attenuation levels were evaluated, SouthCoast and NMFS anticipate 
that the noise attenuation system ultimately chosen will be capable of 
reliably reducing source levels by 10 dB; therefore, modeling results 
assuming 10-dB attenuation are carried forward in this analysis for 
pile driving. See the Proposed Mitigation section for more information 
regarding the justification for the 10-dB attenuation assumption.
Acoustic Propagation Modeling
    To estimate sound propagation during foundation installation, 
JASCO's used the Full Waveform Range-dependent Acoustic Model (FWRAM) 
to combine the outputs of the source model with spatial and temporal 
environmental factors (e.g., location, oceanographic conditions, and 
seabed type) to get time-domain representations of the sound signals in 
the environment and estimate sound field levels ((Limpert et al. 
(2024), Section F.1 in Appendix F of SouthCoast's ITA application)). 
Because the foundation pile is represented as a linear array and FWRAM 
employs the array starter method to accurately model sound propagation 
from a spatially distributed source (MacGillivray and Chapman, 2012), 
using FWRAM ensures accurate characterization of vertical directivity 
effects in the near-field zone. Due to seasonal changes in the 
temperature and salinity of the water column, sound propagation is 
likely to vary among different times of the year. To capture this 
variability, acoustic modeling was conducted using an average sound 
speed profile for a ``summer'' period including the months of May 
through November, and a ``winter'' period including December through 
April. FWRAM computes pressure waveforms via Fourier synthesis of the 
modeled acoustic transfer function in closely spaced frequency bands. 
This model is used to estimate the energy distribution per frequency 
(source spectrum) at a close distance from the source (10 m (32.8 ft)). 
Examples of decidecade spectral levels for each foundation pile type, 
hammer energy, and modeled location, using average summer sound speed 
profile are provided in Limpert et al. (2024).
    Sounds produced by sequential installation of the 9/16-m WTG 
monopiles and 4.5-m pin piles were modeled at two locations. Water 
depths within the Lease Area range from 37 m to 64 m (121 ft to 210 
ft). Sound fields produced during both impact and vibratory 
installation of 9/16-m WTG monopiles and 4.5-m WTG and OSP pin piles 
were modeled at two locations: L01 in the southwest section of the 
lease area in 38 m water depth and L02 in the northeast section of the 
lease area in 53 m (173.9 ft) depth (Figure 2 in Appendix A in Limpert 
et al., 2024). Propagation modeling did not include water depths 
between 54 m and 64 m (deepest location) given the majority of 
foundation locations (i.e., 101 out of 149) occur in depths less than 
54 m (177 ft). The locations were selected to represent the acoustic 
propagation environment within the Lease Area and may not be actual 
foundation locations. JASCO selected alternative locations to model the 
ensonified zones produced during concurrent pile driving because the 
foundation installation locations would be closer together (i.e., 
separated by approximately 2 nm) than those selected for sequential 
foundation installations.
    For impulsive sounds from impact pile driving as well as non-
impulsive sounds from vibratory piling, time-domain representations of 
the pressure waves generated in the water are required for calculating 
SPLrms and SPLpeak at various distances from the 
pile, metrics that are important for characterizing potential impacts 
of pile driving noise on marine mammals. Furthermore, the pile must be 
represented as a distributed source to accurately characterize vertical 
directivity effects in the near-field zone. JASCO used FWRAM to compute 
synthetic pressure waveforms as a function of range and depth via 
Fourier synthesis of transfer functions in closely spaced frequency 
bands, in range-varying marine acoustic environments. Additional 
modeling details are described in Limpert et al. (2024). Impact and 
vibratory pile driving source and propagation modeling provides 
estimates of the distances from the pile

[[Page 53761]]

location to NMFS' Level A harassment and Level B harassment threshold 
isopleths.
    JASCO calculated acoustic ranges, which represent the distance to a 
harassment threshold based on sound propagation through the 
environment, independent of movement of a receiver. The use of acoustic 
ranges (R95) to the Level A harassment 
SELcum metric thresholds to assess the potential for PTS is 
considered an overly conservative method, as it does not account for 
animal movement and behavior and, therefore, assumes that animals are 
essentially stationary at that distance for the entire duration of the 
pile installation, a scenario that does not reflect realistic animal 
behavior. However, because NMFS' Level A harassment 
(SPLpeak) and Level B harassment (SPLrms) 
thresholds refer to instantaneous exposures, acoustic ranges are a 
better representation of distances to these NMFS' instantaneous 
harassment thresholds. These distances were not applied to exposure 
estimation but were used to define the Level B harassment zones for all 
species (see Proposed Mitigation and Monitoring) for WTG and OSP 
foundation installation in summer and winter, and the minimum 
visibility zone for installation of foundations in the NARW EMA (see 
Proposed Mitigation and Monitoring). The following tables present the 
largest acoustic ranges (R95) among modeling sites 
(Figure 2 in Limpert et al., 2024) resulting from JASCO's source and 
propagation models, for both ``summer'' and ``winter.'' Table 15 
presents the R95 distances to the Level A harassment 
(SPLpeak) isopleths. Table 16 provides 
R95 distances to the Level A harassment 
(SELcum) thresholds for impact-only and combined method 
(i.e., vibratory and impact pile driving) installations, respectively. 
Finally, table 17 presents R95 distances for Level B 
harassment thresholds, for impact (160 dB) and vibratory (120 dB) pile 
driving.

Table 15--Acoustic Ranges (R95), in Kilometers (km), to Marine Mammal Level A Harassment Thresholds (SPLpeak) During Impact Pile Driving of 9/16-
            m Monopiles, 4.5-m Pre-Piled WTG Jackets, and 4.5-m Post-Piled OSP Jackets, Assuming 10 dB Attenuation in Both Summer and Winter
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                             Distances to level A (SPLpeak) harassment thresholds (km)
                                                         -----------------------------------------------------------------------------------------------
                      Hearing group                             WTG 9/16-m monopile           WTG 4.5-m pre-piled pin        OSP 4.5-m post-piled pin
                                                         -----------------------------------------------------------------------------------------------
                                                              Summer          Winter          Summer          Winter          Summer          Winter
--------------------------------------------------------------------------------------------------------------------------------------------------------
LFC.....................................................  ..............  ..............  ..............  ..............  ..............  ..............
MFC.....................................................  ..............  ..............  ..............  ..............  ..............  ..............
HFC.....................................................            0.27            0.26            0.12            0.13            0.14            0.13
PW......................................................  ..............  ..............  ..............  ..............  ..............  ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------


   Table 16--Acoustic Ranges (R95), in Kilometers (km), to Marine Mammal Level A Harassment Thresholds (SELcum) During Pile Driving of 9/16-m
             Monopiles, 4.5-m Pre-Piled WTG Jackets, and 4.5-m Post-Piled OSP Jackets, Assuming 10 dB Attenuation in Both Summer and Winter
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                             Distances to level A (SPLcum) harassment thresholds (km)
                                        Impact (I) or    -----------------------------------------------------------------------------------------------
           Hearing group              vibratory \1\ and         WTG 9/16-m monopile           WTG 4.5-m pre-piled pin        OSP 4.5-m post-piled pin
                                        impact (V/I)     -----------------------------------------------------------------------------------------------
                                        installation          Summer          Winter          Summer          Winter          Summer          Winter
--------------------------------------------------------------------------------------------------------------------------------------------------------
LFC...............................  I...................            6.09            6.68            4.94            5.16            5.83            6.21
                                    V/I.................            6.19             6.8            2.11            2.15  ..............  ..............
MFC...............................  I...................  ..............  ..............  ..............  ..............  ..............  ..............
                                    V/I.................  ..............  ..............  ..............  ..............  ..............  ..............
HFC...............................  I...................            0.26             0.3            0.09            0.09            0.11            0.12
                                    V/I.................             0.2             0.2            0.02            0.02  ..............  ..............
PW................................  I...................            0.79            0.79            0.48            0.49            0.68            0.71
                                    V/I.................            0.81            0.85            0.11            0.11  ..............  ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Vibratory pile driving applies to Project 2 only.


Table 17--Acoustic Ranges (R95), in Kilometers (km), to the Marine Mammal Level B Harassment Thresholds During Impact (160 dB) and Vibratory \1\
   (120 dB) Pile Driving of 9/16-m Monopiles, 4.5-m Pre-Piled WTG Jackets, and 4.5-m Post-Piled OSP Jackets, Assuming 10 dB Attenuation, in Summer and
                                                                         Winter
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                             Distances to level B (SPLrms) harassment thresholds (km)
                                                         -----------------------------------------------------------------------------------------------
                  Installation approach                         WTG 9/16-m monopile           WTG 4.5-m pre-piled pin        OSP 4.5-m post-piled pin
                                                         -----------------------------------------------------------------------------------------------
                                                              Summer          Winter          Summer          Winter          Summer          Winter
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact..................................................            7.44            8.63            4.18            4.41            4.88            5.24
Vibratory...............................................           42.02           84.63           15.83           21.92  ..............  ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Vibratory pile driving applies to Project 2 only.


[[Page 53762]]

    To assess the extent to which marine mammal harassment might occur 
as a result of movement within this acoustic environment, JASCO next 
conducted animal movement and exposure modeling.
Animal Movement Modeling
    To estimate the probability of exposure of animals to sound above 
NMFS' harassment thresholds to during foundation installation, JASCO's 
Animal Simulation Model Including Noise Exposure (JASMINE) was used to 
integrate the sound fields generated from the source and propagation 
models described above with species-typical behavioral parameters 
(e.g., swim speeds dive patterns). The parameters used for forecasting 
realistic behaviors (e.g., diving, foraging, and surface times) were 
determined and interpreted from marine species studies (e.g., tagging 
studies) where available, or reasonably extrapolated from related 
species (Limpert et al., 2024).
    Applying animal movement and behavior within the modeled noise 
fields allows for a more realistic indication of the distances at which 
PTS acoustic thresholds are reached that considers the accumulation of 
sound over different durations. Sound exposure models such as JASMINE 
use simulated animals (animats) to sample the predicted 3-D sound 
fields with movement derived from animal observations (see Limpert et 
al., 2024). Animats that exceed NMFS' acoustic thresholds are 
identified and the range (distance from the noise source) for the 
exceedances determined. The output of the simulation is the exposure 
history for each animat accumulated within the simulation. An 
individual animat's sound exposure levels are summed over a specific 
duration, (24 hours), to determine its total received acoustic energy 
(SEL) and maximum received SPLPK and SPLrms. 
These received levels are then compared to the harassment threshold 
criteria. The combined history of all animats gives a probability 
density function of exposure above threshold levels. The number of 
animals expected to exceed the regulatory thresholds is determined by 
scaling the number of predicted animat exposures by the species-
specific density of animals in the area. By programming animats to 
behave like the 16 marine mammal species that may be exposed to pile 
driving noise, the sound fields are sampled in a manner similar to that 
expected for real animals.
    Vibratory setting of piles followed by impact pile driving is being 
considered for Project 2 (Scenarios 2 and 3). Given the qualities of 
vibratory pile driving noise (e.g., continuous, lower hammer energy), 
Level A harassment (PTS) is not an anticipated impact on marine mammals 
incidental to SouthCoast's use of this method. Although the potential 
to induce hearing loss is low during vibratory driving, it does 
introduce some SEL exposure that must be considered in the 24-hour 
SELcum estimates. For this reason, JASCO computed acoustic 
ranges from the combined sound energy from vibratory and impact pile 
driving. These results are presented in Appendix G in Limpert et al. 
(2024). The PTS-onset SEL thresholds are lower for impact piling than 
for vibratory piling (table 7) so, to be conservative, when estimating 
acoustic ranges and the number of animats exposed to potentially 
injurious sound levels from both impact and vibratory pile driving (for 
those piles that may require both methods), the lower (impulsive) SEL 
criteria were applied to determine if thresholds were exceeded.
    Estimating the number of animats that may be exposed to sound above 
a behavioral SPL response threshold is simpler because it does not 
require integrating sound pressure over long time periods. This 
calculation was done separately for vibratory and impact pile driving 
because these two sound sources use different thresholds, and they are 
temporally separated activities (i.e., impact follows vibratory pile 
driving). The numbers of animats exposed above the 120 dB (vibratory) 
and 160 dB (impact) Level B harassment thresholds are calculated 
individually and then the resulting numbers are combined to get total 
behavioral exposures from a single pile installed at each 
representative location when both hammer types are expected to be used 
on a pile. Individual animats that are exposed above behavioral 
thresholds for both vibratory and impact pile driving are only counted 
once to avoid over-estimation.
    For modeled animats that have received enough acoustic energy to 
exceed a given harassment threshold, the exposure range for each animal 
is defined as the closest point of approach (CPA) to the source made by 
that animal while it moved throughout the modeled sound field, 
accumulating received acoustic energy. The CPA for each of the species-
specific animats during a simulation is recorded and then the CPA 
distance that accounts for 95 percent of the animats that exceed an 
acoustic threshold is determined. The ER95 (95 
percent exposure radial distance) is the horizontal distance that 
includes 95 percent of the CPAs of animats exceeding a given impact 
threshold. The ER95 ranges are species-specific 
rather than categorized only by any functional hearing group, which 
allows for the incorporation of more species-specific biological 
parameters (e.g., dive durations, swim speeds) for assessing the 
potential for PTS from pile driving. Furthermore, because these 
ER95 ranges are species-specific, they can be used 
to develop mitigation monitoring or shutdown zones.
    As described in the Detailed Description of Specific Activity 
section, SouthCoast proposed construction schedules that include both 
sequential and concurrent foundation installations. For sequential 
installations (both vibratory and/or impact) of two monopiles 
foundations or four jacket pin piles per day, two sites were used for 
modeling (see Figures 7 and 8, Section 2.51 of Appendix A in Limpert et 
al., 2024), both considered representative locations of the Lease Area 
(one location for each foundation). Animats were exposed to only one 
sound field at a time. Received levels were accumulated over each 
animat's track over a 24-hour time window to derive sound exposure 
levels (SEL). Instantaneous single-exposure metrics (e.g., 
SPLrms and SPLpeak) were recorded at each 
simulation time step, and the maximum received level was reported.
    Concurrent operations were handled slightly differently to capture 
the effects of installing piles spatially close to each other (i.e., 2 
nm (2.3 mi; 3.7 km)). The sites chosen for exposure modeling for 
concurrent operations are shown in Figure 9, Section 2.51 in Limpert et 
al. (2024). When simulating concurrent operations in JASMINE, sound 
fields from separate piles may be overlapping in time and space. For 
cumulative metrics (SELcum), received energy from each sound 
field the animat encounters is summed over a 24-hour time window. For 
SPL, received levels were summed within each simulation time step and 
the resultant maximum SPL over all time steps was carried forward. For 
both sequential and concurrent operations, the resulting cumulative or 
maximum received levels were then compared to the NMFS' thresholds 
criteria within each analysis period.
    Additional assumptions used in modeling for each year of 
construction are summarized in table 18. As discussed previously, 
modeling assumed SouthCoast would install Project 1 WTG foundations 
using only impact pile driving and Project 2 WTG foundations using 
vibratory and/or impact pile driving. All pin piles supporting OSP 
jacket foundations would be impact driven. In addition, modeling 
assumed a seasonal restriction

[[Page 53763]]

on pile driving from January 1 through April 30. However, as previously 
described, to provide additional North Atlantic right whale protection, 
SouthCoast would not install foundation in the NARW EMA from October 16 
through May 31 or throughout the rest of the Lease Area from January 1 
to May 15.

                                   Table 18--Assumptions Used in WTG and OSP Foundation Installation Exposure Modeling
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                             Project 1                                     Project 2
                                                              ------------------------------------------------------------------------------------------
                          Parameter                                WTG                                    WTG          WTG
                                                                monopiles   WTG jackets  OSP jackets   monopiles    monopiles   WTG jackets  OSP jackets
                                                                scenario 1   scenario 2                scenario 1   scenario 2   scenario 3
--------------------------------------------------------------------------------------------------------------------------------------------------------
Number of foundations........................................           71           85            1           68           73           62            1
Pile diameter (m)............................................         9/16          4.5          4.5         9/16         9/16          4.5          4.5
Piles per foundation.........................................            1            4        12-16            1            1            4        12-16
Penetration depth (m)........................................           35           60           60           35           35           60           60
Max hammer energy (kJ).......................................         6600         3500         3500         6600         6600         3500         3500
Impact or Vibratory..........................................       Impact       Impact       Impact       Impact         Both         Both       Impact
Number of impact strikes \1\.................................         7000         4000         4000         7000    7000/5000    4000/2667         4000
Piles/day....................................................          1-2            4            4          1-2          1-2            4            4
Piling days..................................................           59           85         0.75           53           49           62         0.75
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ The second value is the number of strikes required when vibratory preceded impact pile driving.

    All proposed construction scenarios, including foundation type, 
installation method, number of monopiles or pin piles installed per 
day, and the rate of installation were presented in table 2 in the 
Detailed Description of Specific Activities section.
    Tables 19-23 summarize the monthly construction schedules for each 
scenario assumed for modeling, including installation sequence and 
method, and the number of pile driving days per month. However, 
construction schedules cannot be fully predicted due to uncontrollable 
environmental factors (e.g., weather) and installation schedules 
include variability (e.g., due to drivability). The total number of 
construction days per month would be dependent on a number of factors, 
including environmental conditions, planning, construction, and 
installation logistics. As described previously, SouthCoast assumed 
that for sequential WTG foundation installations (using a single 
vessel), a maximum of 2 WTG monopiles or 4 OSP piled jacket pin piles 
may be driven in 24 hours. For concurrent installation (using two 
vessels), a maximum of 2 WTG monopiles and 4 OSP piled jacket pin piles 
or 4 WTG and 4 OSP pin piles may be driven in 24 hours. It is unlikely 
that these maximum installation rates would be consistently attainable 
throughout the construction phase, but this schedule was considered to 
have the greatest potential for Level A harassment (PTS) and was, 
therefore, carried forward into take estimation.

                            Table 19--SouthCoast's Potential Foundation Installation Schedule for Project 1 Scenario 1 (P1S1)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                Vibratory & impact          Concurrent                Impact                          Totals
                                         --------------------------------     impact     ---------------------------------------------------------------
                                                   WTG monopile          ----------------          WTG monopile
                                         -------------------------------- WTG monopile & ---------------------------------------------------------------
                  Month                                                   OSP jacket pin
                                                                               piles
                                               2/day           1/day     ----------------      2/day           1/day        Total piles     Total days
                                                                           1/day & 4/day
--------------------------------------------------------------------------------------------------------------------------------------------------------
May.....................................               0               0               0               0               2               2               2
June....................................               0               0               0               1               8              10               9
July....................................               0               0               0               3              10              16              13
Aug.....................................               0               0               0               4              10              18              14
Sept....................................               0               0               0               3               9              15              12
Oct.....................................               0               0               3               1               3              20               7
Nov.....................................               0               0               0               0               1               1               1
Dec.....................................               0               0               0               0               1               1               1
                                         ---------------------------------------------------------------------------------------------------------------
    Total...............................               0               0               3              12              44              83              59
--------------------------------------------------------------------------------------------------------------------------------------------------------


        Table 20--SouthCoast's Potential Foundation Installation Schedule for Project 1 Scenario 2 (P1S2)
----------------------------------------------------------------------------------------------------------------
                                    Vibratory &     Concurrent        Impact                  Totals
                                      impact          impact     -----------------------------------------------
                                 --------------------------------   WTG jacket
                                    WTG jacket    WTG monopile & -----------------------------------------------
              Month              ---------------- OSP jacket pin
                                                       piles
                                       4/day     ----------------      4/day        Total piles     Total days
                                                   1/day & 4/day
----------------------------------------------------------------------------------------------------------------
May.............................               0               0               8              32               8
June............................               0               0              10              40              10

[[Page 53764]]

 
July............................               0               0              12              48              12
Aug.............................               0               0              14              56              14
Sept............................               0               0              12              48              12
Oct.............................               0               4              12              80              16
Nov.............................               0               0              10              40              10
Dec.............................               0               0               3              12               3
                                 -------------------------------------------------------------------------------
    Total.......................               0               0              81             356              85
----------------------------------------------------------------------------------------------------------------


                            Table 21--SouthCoast's Potential Foundation Installation Schedule for Project 2 Scenario 1 (P2S1)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                Vibratory & impact          Concurrent                Impact                          Totals
                                         --------------------------------     impact     ---------------------------------------------------------------
                                                   WTG monopile          ----------------          WTG monopile
                                         -------------------------------- WTG monopile & ---------------------------------------------------------------
                  Month                                                   OSP jacket pin
                                                                               piles
                                               2/day           1/day     ----------------      2/day           1/day        Total piles     Total days
                                                                           1/day & 4/day
--------------------------------------------------------------------------------------------------------------------------------------------------------
May.....................................               0               0               0               0               2               2               2
June....................................               0               0               0               3               6              12               9
July....................................               0               0               0               3               6              12               9
Aug.....................................               0               0               0               3               6              12               9
Sept....................................               0               0               0               3               6              12               9
Oct.....................................               0               0               3               3               6              27              12
Nov.....................................               0               0               0               0               2               2               2
Dec.....................................               0               0               0               0               1               1               1
                                         ---------------------------------------------------------------------------------------------------------------
    Total...............................               0               0               0              15              35              80              53
--------------------------------------------------------------------------------------------------------------------------------------------------------


                            Table 22--SouthCoast's Potential Foundation Installation Schedule for Project 2 Scenario 2 (P2S2)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                Vibratory & impact          Concurrent                Impact                          Totals
                                         --------------------------------     impact     ---------------------------------------------------------------
                                                   WTG monopile          ----------------          WTG monopile
                                         -------------------------------- WTG monopile & ---------------------------------------------------------------
                  Month                                                   OSP jacket pin
                                                                               piles
                                               2/day           1/day     ----------------      2/day           1/day        Total piles     Total days
                                                                           1/day & 4/day
--------------------------------------------------------------------------------------------------------------------------------------------------------
May.....................................               0               0               0               0               2               2               2
June....................................               2               4               0               0               0               8               6
July....................................               6               4               0               0               0              16              10
Aug.....................................               7               4               0               0               0              18              11
Sept....................................               6               4               0               0               0              16              10
Oct.....................................               3               2               3               0               0              23               8
Nov.....................................               0               1               0               0               0               1               1
Dec.....................................               0               0               0               0               1               1               1
                                         ---------------------------------------------------------------------------------------------------------------
    Total...............................              24              19               0               0               3              85              49
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 53765]]


        Table 23--SouthCoast's Potential Foundation Installation Schedule for Project 2 Scenario 3 (P2S3)
----------------------------------------------------------------------------------------------------------------
                                    Vibratory &     Concurrent        Impact                  Totals
                                      impact          impact     -----------------------------------------------
                                 --------------------------------   WTG jacket
                                    WTG jacket    WTG monopile & -----------------------------------------------
              Month              ---------------- OSP jacket pin
                                                       piles
                                       4/day     ----------------      4/day        Total piles     Total days
                                                   1/day & 4/day
----------------------------------------------------------------------------------------------------------------
May.............................               0               0               5              20               5
June............................               9               0               0              36               9
July............................               9               0               0              36               9
Aug.............................               9               0               0              36               9
Sept............................               9               0               0              36               9
Oct.............................               6               4               0              56              10
Nov.............................               6               0               0              24               6
Dec.............................               0               0               5              20               5
                                 -------------------------------------------------------------------------------
    Total.......................              48               4              10             264              62
----------------------------------------------------------------------------------------------------------------

    By incorporating animal movement into the calculation of ranges to 
time-dependent thresholds (SEL metrics), ER95 values 
provide a more realistic assessment of the distances within which 
acoustic thresholds may be exceeded. This also means that different 
species within the same hearing group can have different exposure 
ranges as a result of species-specific movement patterns. Substantial 
differences (greater than 500 m (1,640 ft)) between species within the 
same hearing group occurred for low frequency-cetaceans, so Level A 
harassment (PTS) ER95 values are shown separately 
for those species (tables 24-29). For mid-frequency cetaceans and 
pinnipeds, the largest value from any single species was selected.
    Projects 1 and 2 would include sequential WTG foundation 
installations using impact pile driving only and both vibratory and 
impact pile driving (Project 2 only), and concurrent WTG and OSP 
installations using only impact pile driving, each of which generates 
different ER95 distances. The Level A harassment 
(PTS) ER95 distances for sequential installation of 
WTG foundations using only impact pile driving are shown in table 24 
for both summer and winter. SouthCoast does not anticipate conducting 
vibratory or concurrent pile driving in December, thus the Level A 
harassment (PTS) ER95 distances for sequential 
installation of WTG foundations (both monopile and pin-piled jacket) 
using both vibratory and impact pile driving are shown in table 25 for 
summer only. Lastly, Level A harassment (PTS) ER95 
distances for potential concurrent installation of WTG and OSP 
foundations using impact pile driving (also limited to ``summer'' for 
modeling) are shown in table 26.
    Comparison of the results in table 24 and table 26 show that the 
case assuming sequential installation of two WTG monopiles per day and 
concurrent installation of two WTG monopiles and 4 OSP piles per day 
yield very similar results. This may seem counterintuitive, given the 
assumed number of piles installed per day for concurrent installations 
is larger than that assumed for sequential installations, thus it might 
be expected that Level A harassment (PTS) ER95 
distances would be larger for concurrent installations. However, for 
that result to occur, animal movement modeling would have to show that 
animals would routinely occur close enough to one pile driving location 
(e.g., WTG monopile) to accumulate enough sound energy without 
exceeding the Level A harassment SELcum threshold, and then 
also occur at the second pile driving location (e.g., OSP jacket) at a 
distance close enough to accumulate the remaining sound energy needed 
to cross the SELcum threshold. The animal movement modeling 
showed this sequence of events did not happen often enough during 
concurrent installations of WTG monopile and OSP jacket foundations to 
cause a consistent increase in the Level A harassment (PTS) 
ER95 distances across all species. This sequence of 
events did occur more often during concurrent installation of WTG 
jacket and OSP jacket foundation installations, thus the Level A 
harassment (PTS) ER95 distances for concurrent 
installations were consistently larger than for installation of a 
single WTG jacket foundation on a given day (table 26). This was likely 
a result of the overall longer duration of pile driving per day 
required for installing 4 pin piles for each jacket foundation.

 Table 24--Exposure Ranges (ER95%) \1\ to the Marine Mammal PTS (Level A) Cumulative Sound Exposure Level (SELcum) Thresholds for Sequential Impact Pile
 Driving Installation of One or Two 9/16-m WTG Monopiles, Four 4.5-m WTG Jacket Pin Piles, or Four 4.5-m OSP Jacket Pin Piles in One Day, Assuming 10 dB
                                             of Broadband Noise Attenuation in Summer (S) and Winter (W) \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                Range (km)
                                SELcum threshold -------------------------------------------------------------------------------------------------------
                                    (dB re 1       9/16-m WTG monopiles (1   9/16-m WTG monopiles (2    4.5-m WTG jacket pin      4.5-m OSP jacket pin
        Hearing group          [mu]Pa2[middot]s)         piles/day)                piles/day)            piles (4 piles/day)       piles (4 piles/day)
                                                 -------------------------------------------------------------------------------------------------------
                                                       S            W            S           W\3\          S            W            S            W
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale *.................             183     ...........  ...........  ...........  ...........  ...........  ...........  ...........  ...........
Fin whale *..................  .................         3.99         4.49         4.15  ...........         2.37         2.55         3.18         3.50
Humpback whale...............  .................         3.13         3.66         3.46  ...........         1.88         1.96         2.36         2.54
Minke whale..................  .................         2.41            3         2.42  ...........         1.24         1.28         1.58         1.79
N.Atl. right whale *.........  .................         2.83         3.23         2.95  ...........         1.73         1.85         2.01         2.13
Sei whale *..................  .................         3.06         3.38         3.19  ...........         1.96         2.22         2.59         2.72

[[Page 53766]]

 
Mid-frequency................             185               0            0            0  ...........            0            0            0            0
High-frequency...............             155               0            0            0  ...........            0            0            0            0
Phocids......................             185             0.4         0.34         0.12  ...........            0         0.32         0.41         0.41
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.
\1\ These are the maximum ER95% values among modeling locations (L01 and L02 in Limpert et al., 2024).
\2\ For acoustic propagation modeling, two average sound speed profiles were used, one for the ``summer'' season (May-November) and a second for the
  ``winter'' season (December).
\3\ Given the small number of foundation installations planned for December (see tables 19-23), modeling assumed installation of only a single monopile
  per day for ``winter.''


 Table 25--Exposure Ranges (ER95%) \1\ to the Marine Mammal Level A Cumulative Sound Exposure Level (SELcum) Thresholds During Sequential Vibratory \2\
 and Impact Pile Driving Installation of One or Two 9/16-m WTG Monopiles or Four 4.5-m WTG Jacket Pin Piles Assuming 10 dB of Attenuation in Summer \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                             Range (km)
                                                                           -----------------------------------------------------------------------------
                                                         SELcum threshold     WTG monopile (1 pile/    WTG monopile (2 piles/    WTG jacket pin piles (4
                    Hearing group                            (dB re 1                 day)                      day)                   piles/day)
                                                       [mu]Pa\2\[middot]s) -----------------------------------------------------------------------------
                                                                               Impact     Vibratory      Impact     Vibratory      Impact     Vibratory
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale *.........................................              183      ...........  ...........  ...........  ...........  ...........  ...........
Fin whale *..........................................  ...................         3.98            0         4.11         0.08         2.25            0
Humpback whale.......................................  ...................         3.10            0         3.49         0.18         1.84            0
Minke whale..........................................  ...................         2.41            0         2.37            0         1.13            0
N.Atl. right whale *.................................  ...................         2.81            0         3.07         0.13         1.57            0
Sei whale *..........................................  ...................         3.11            0         3.13            0         1.84            0
Mid-frequency........................................              185                0            0            0            0            0            0
High-frequency.......................................              155                0            0            0            0            0            0
Phocids..............................................              185             0.01            0         0.11            0            0            0
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.
\1\ These are the maximum ER95% values among modeling locations (L01 and L02 in Limpert et al., 2024).
\2\ SouthCoast proposed vibratory pile driving for Project 2 (Scenarios 2 and 3) but not for Project 1.
\3\ For acoustic propagation modeling, two average sound speed profiles were used, one for the ``summer'' season (May-November) and a second for the
  ``winter'' season (December). Modeling assumed vibratory pile driving would only occur in ``summer,'' thus, table 25 does not present ``winter''
  values.


   Table 26--Exposure Ranges (ER95%) \1\ to the Marine Mammal Level A Cumulative Sound Exposure Level (SELcum)
Thresholds During Concurrent \2\ Impact Pile Driving Installation of Two 9/16-m WTG Monopiles and Four 4.5-m OSP
 Jacket Pin Piles, or Four 4.5-m WTG Jacket Pin Piles \2\ and Four 4.5-m OSP Jacket Pin Pile in One Day Assuming
                               10 dB of Broadband Noise Attenuation in Summer \3\
----------------------------------------------------------------------------------------------------------------
                                                                                            Range (km)
                                                                                 -------------------------------
                                                                                     16-m WTG        4.5-m WTG
                                                               SELcum threshold    monopiles (2     jacket pin
                       Hearing group                               (dB re 1       piles/day) and  piles (4 piles/
                                                             [mu]Pa\2\[middot]s)     4.5-m OSP    day) and 4.5-m
                                                                                    jacket pin    OSP jacket pin
                                                                                  piles (4 piles/ piles (4 piles/
                                                                                       day)            day)
----------------------------------------------------------------------------------------------------------------
Low-frequency..............................................                183
Blue whale.................................................  ...................  ..............  ..............
Fin whale *................................................  ...................            4.53            3.58
Humpback whale.............................................  ...................            3.71            2.57
Minke whale................................................  ...................            2.31            1.56
N.Atl. right whale *.......................................  ...................            3.07            1.92
Sei whale *................................................  ...................            3.44            2.31
Mid-frequency..............................................                185                 0               0
High-frequency.............................................                155                 0               0
Phocids....................................................                185               0.3            0.17
----------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Act.
\1\ These are the maximum ER95% values among modeling locations (L01 and L02 in Limpert et al., 2024).
\2\ SouthCoast proposed concurrent impact pile driving of WTG and OSP foundations for Projects 1 and 2.
\3\ For acoustic propagation modeling, two average sound speed profiles were used, one for the ``summer'' season
  (May-November) and a second for the ``winter'' season (December).


[[Page 53767]]

    In addition to ER95 distances to Level A 
harassment (PTS) thresholds, exposure modeling produced 
ER95 distances to the Level B harassment 160 dB 
SPLrms (impact pile driving) and 120 dB SPLrms 
(vibratory pile driving) thresholds. The following tables provide the 
Level B harassment ER95 distances for 1) sequential 
installation of WTG foundations using only impact pile driving for 
summer and winter (table 27); 2) summer-only sequential installation of 
WTG foundations (both monopile and pin-piled jacket) using both 
vibratory and impact pile driving (table 28); and 3) concurrent 
installation of WTG monopile and OSP pin-piled jacket foundations 
(table 29, also limited to ``summer''). These ranges were used to 
define the outer perimeter around the Lease Area from which Roberts et 
al. (2016, 2023) model data density grid cells were selected for 
exposure estimation.

Table 27--Exposure Ranges (ER95%) \1\ to the Marine Mammal 160 dB Level B Harassment (Splrms) Threshold for Sequential Impact Pile Driving Installation of One or Two 9/16-m WTG Monopiles, Four
                    4.5-m WTG Jacket Pin Piles, or Four 4.5-m OSP Jacket Pin Piles in One Day, Assuming 10 dB of Broadband Noise Attenuation in Summer (S) and Winter (W) \2\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                            Range (km)
                                                                 -------------------------------------------------------------------------------------------------------------------------------
                                                                  9/16-m WTG monopiles  (1 piles/ 9/16-m WTG monopiles  (2 piles/ 4.5-m WTG jacket pin piles  (4  4.5-m OSP jacket pin piles  (4
                             Species                                           day)                            day)                         piles/day)                      piles/day)
                                                                 -------------------------------------------------------------------------------------------------------------------------------
                                                                         S               W               S             W \3\             S               W               S               W
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic Right whale *....................................            6.82            7.66            6.71  ..............            3.73            3.85            4.28            4.54
Blue Whale *....................................................  ..............  ..............  ..............  ..............  ..............  ..............  ..............  ..............
Fin Whale *.....................................................            7.08            8.33            7.03  ..............            3.92            4.27            4.55            4.94
Sei Whale *.....................................................            7.04            8.17            6.86  ..............            3.85            3.90            4.42            4.88
Minke Whale.....................................................            6.61            7.64            6.68  ..............            3.47            3.67            4.34            4.60
Humpback Whale..................................................            6.97            8.03            6.79  ..............            3.77            4.01            4.45            4.82
Sperm Whale *...................................................            6.93            7.93            6.75  ..............            3.73            3.92            4.34            4.72
Atlantic Spotted Dolphin........................................            6.94            8.17            6.64  ..............            3.80            3.87            4.40            4.73
Atlantic White-Sided Dolphin....................................            6.57            7.53            6.54  ..............            3.55            3.61            4.14            4.38
Bottlenose Dolphin, Offshore....................................            5.51            6.55            5.46  ..............            3.08            3.22            3.72            3.86
Common Dolphin..................................................            6.67            7.61            6.44  ..............            3.63            3.80            4.38            4.60
Pilot Whale.....................................................            6.80            7.65            6.60  ..............            3.66            3.76            4.31            4.64
Risso's Dolphin.................................................            7.02            7.89            6.87  ..............            3.68            4.08            4.42            4.71
Harbor Porpoise.................................................            6.67            7.54            6.67  ..............            3.47            3.75            4.31            4.58
Gray Seal.......................................................            7.48            8.58            7.29  ..............            4.04            4.29            4.68            5.18
Harbor Seal.....................................................            6.91            7.87            6.84  ..............            3.61            4.00            4.40            4.75
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.
\1\ These are the maximum ER95% values among modeling locations (L01 and L02 in Limpert et al., 2024).
\2\ For acoustic propagation modeling, two average sound speed profiles were used, one for the ``summer'' season (May-November) and a second for the ``winter'' season (December).
\3\ Given the small number of foundation installations planned for December (see tables 19-23), modeling assumed installation of only a single monopile per day for ``winter.''


 Table 28--Exposure Ranges (ER95%) \1\ to the Marine Mammal 160 dB and 120 dB Level B Harassment (SPLrms) Thresholds During Sequential Vibratory \2\ and
    Impact Pile Driving Installation of One or Two 9/16-m WTG Monopiles \3\ or Four 4.5-m WTG Jacket Pin Piles \4\ Assuming 10 dB of Broadband Noise
                                                                Attenuation in Summer \5\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                    Range (km)
                                                         -----------------------------------------------------------------------------------------------
                                                             WTG monopile (1 pile/day)      WTG monopile (2 piles/day)    WTG jacket pin piles (4 piles/
                         Species                         ----------------------------------------------------------------              day)
                                                                                                                         -------------------------------
                                                              Impact         Vibratory        Impact         Vibratory        Impact         Vibratory
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale..............................            6.77           39.14            6.72           38.20            5.12           15.21
Blue Whale *............................................  ..............  ..............  ..............  ..............  ..............  ..............
Fin Whale...............................................            7.06           41.83            7.00           41.69            5.48           15.75
Sei Whale...............................................            7.01           41.15            6.87           40.46            5.35           15.43
Minke Whale.............................................            6.65           38.77            6.69           38.49            5.06           14.99
Humpback Whale..........................................            6.96           39.71            6.84           39.06            5.23           15.47
Sperm Whale.............................................            6.83           40.64            6.81           40.27            5.32           15.27
Atlantic Spotted Dolphin................................            6.90           40.92            6.65           39.53            5.35           15.72
Atlantic White-Sided Dolphin............................            6.64           38.50            6.58           37.57            5.03           14.67
Bottlenose Dolphin, Offshore............................            5.46           34.63            5.42           33.05            4.32           13.22
Common Dolphin..........................................            6.74           40.99            6.43           39.94            5.17           15.11
Pilot Whale.............................................            6.70           40.42            6.56           39.17            5.12           15.22
Risso's Dolphin.........................................            6.97           41.86            6.86           41.27            5.26           15.45
Harbor Porpoise.........................................            6.68           37.31            6.59           36.86            5.16           14.85
Gray Seal...............................................            7.49           40.66            7.30           40.38            5.54           15.68
Harbor Seal.............................................            6.81           39.66            6.84           39.28            5.11           14.91
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.
\1\ These are the maximum ER95% values among modeling locations (L01 and L02 in Limpert et al., 2024).
\2\ SouthCoast proposed vibratory pile driving for Project 2, Scenarios 2 and 3, but not for Project 1.

[[Page 53768]]

 
\3\ Monopiles installed by 20 minutes of vibratory pile driving using HX-CV640 hammer followed by 5,000 strikes using NNN 6600 impact hammer.
\4\ Pin piles installed by 90 minutes of vibratory pile driving using S-CV640 hammer followed by 2,667 strikes using MHU 3500S impact hammer.
\5\ For acoustic propagation modeling, two average sound speed profiles were used, one for the ``summer'' season (May-November) and a second for the
  ``winter'' season (December). Modeling assumed vibratory pile driving would only occur in ``summer,'' thus, table 28 does not present ``winter''
  values.


  Table 29--Exposure Ranges (ER95%) to the Marine Mammal 160 dB Level B
   Harassment (SPLrms) Threshold During Concurrent Impact Pile Driving
 Installation of Two 9/16-m WTG Monopiles and Four 4.5-m OSP Jacket Pin
 Piles, or Four 4.5-m Wtg Jacket Pin Piles and Four 4.5-m OSP Jacket Pin
  Pile in One Day Assuming 10 dB of Broadband Noise Attenuation in the
                               Summer \1\
------------------------------------------------------------------------
                                                    Range (km)
                                         -------------------------------
                                             16-m WTG        4.5-m WTG
                                           monopiles (2     jacket pin
                 Species                  piles/day) and  piles (4 piles/
                                             4.5-m OSP    day) and 4.5-m
                                            jacket pin    OSP jacket pin
                                          piles (4 piles/ piles (4 piles/
                                               day)            day)
------------------------------------------------------------------------
Fin whale *.............................            4.53            3.58
Humpback whale..........................            3.71            2.57
Minke whale.............................            2.31            1.56
N.Atl. right whale *....................            3.07            1.92
Sei whale *.............................            3.44            2.31
Mid-frequency...........................               0               0
High-frequency..........................               0               0
Phocids.................................             0.3            0.17
------------------------------------------------------------------------
* Denotes species listed under the Endangered Act.
\1\ For acoustic propagation modeling, two average sound speed profiles
  were used, one for the ``summer'' season (May-November) and a second
  for the ``winter'' season (December). Modeling assumed concurrent
  installations would only occur in October, thus table 29 present
  values for summer only.

    SouthCoast modeled potential Level A harassment and Level B 
harassment density-based exposure estimates for all five foundation 
installation schedules (P1S1-P2S3), all of which include sequential 
pile driving and concurrent pile driving. In creating the installation 
schedules used for exposure modeling, the total number of installations 
was spread across all potential months in which they might occur (May-
December) in order to incorporate the month-to-month variability in 
species densities. SouthCoast assumed that the OSP jacket foundations 
would be installed in October for each Project.
    For both WTG and OSP foundation installations, mean monthly 
densities were calculated by first selecting density data from 5 x 5 km 
(3.1 x 3.1 mi) grid cells (Roberts et al., 2016; 2023) both within the 
Lease Area and beyond its boundaries to predetermined perimeter 
distances. The widths of the perimeter (referred to as a ``buffer'' in 
SouthCoast's application) around the activity area used to select 
density data were determined using the ER95, 
distances to the isopleths corresponding to Level A harassment (tables 
24-26) and Level B harassment (table 27-29) thresholds, assuming 10-dB 
attenuation, which vary according to sound source (impact/vibratory 
piling) and season. For each species, foundation type and number, 
installation method, and season, the most appropriate density perimeter 
was selected from the predetermined distances (i.e., 1 km (0.6 mi), 5 
km (3.1 mi), 10 km (6.2 mi), 15 km (9.3 mi), 20 km (12.4 mi), 30 km 
(18.6 mi), 40 km (25 mi), and 50 km (31.1 mi)) by rounding the 
ER95 up to the nearest predetermined perimeter size. 
For example, if the Level A harassment (PTS) ER95 
was 7.1 km (4.4 mi) for a given species and activity, a 10-km (6.2-mi) 
perimeter was created around the Lease Area and used to calculate mean 
monthly densities that were used in foundation installation Level A 
harassment (PTS) exposure estimates (e.g., table 30). Similarly, if the 
160 dB Level B harassment ER95 was 20.1 km (12.5 mi) 
for a given species or activity, a 30-km (18.6-mi) perimeter around the 
Lease Area was created and used to calculate mean monthly densities for 
exposure estimation. In cases where the ER95 was 
larger than 50 km (31.1 mi), the 50-km (31.1-mi) perimeter was used. 
The 50-km (31.1-mi) limit is derived from studies of mysticetes that 
demonstrate received levels, distance from the source, and behavioral 
context are known to influence the probability of behavioral response 
(Dunlop et al., 2017). Please see Figure 10 in SouthCoast's ITA 
Application for an example of a density map showing the Roberts et al. 
(2016; 2023) density grid cells overlaid on a map of the Lease Area. 
Given the extensive number of density tables used for exposure 
modeling, we do not present them here beyond the example provided in 
table 30. Please see tables in Section H.2.1.1 of Appendix H in Limpert 
et al. (2024) for densities within the areas defined by additional 
perimeter sizes (i.e., 1 km (0.6 mi), 5 km (3.1 mi), 10 km (6.2 mi), 15 
km (9.3 mi), 20 km (12.4 mi), 30 km (18.6 mi), 40 km (25 mi), and 50 km 
(31.1 mi)).

[[Page 53769]]



                Table 30--Mean Monthly Marine Mammal Density Estimates (Animals km\1\) Within 10-km (6.2 mi) of the Lease Area Perimeter
--------------------------------------------------------------------------------------------------------------------------------------------------------
             Species                 Jan       Feb       Mar       Apr       May       Jun      July       Aug       Sep       Oct       Nov       Dec
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale *....    0.0054    0.0060    0.0054    0.0050    0.0037    0.0008    0.0004    0.0003    0.0004    0.0006    0.0011    0.0033
Blue Whale *....................    0.0000     0.000     0.000     0.000     0.000     0.000    0.0000     0.000     0.000     0.000     0.000     0.000
Fin Whale *.....................    0.0022    0.0018    0.0015    0.0015    0.0030    0.0029    0.0047    0.0036    0.0027    0.0009    0.0005    0.0004
Sei Whale *.....................    0.0004    0.0003    0.0005    0.0012    0.0019    0.0007    0.0002    0.0001    0.0002    0.0004    0.0009    0.0007
Minke Whale.....................    0.0011    0.0013    0.0014    0.0075    0.0151    0.0175    0.0080     0.048    0.0054    0.0050    0.0005    0.0007
Humpback Whale..................    0.0003    0.0003    0.0005    0.0018    0.0031    0.0035    0.0021    0.0012    0.0017    0.0025    0.0020    0.0003
Sperm Whale *...................    0.0005    0.0002    0.0002    0.0000    0.0002    0.0003    0.0005    0.0017    0.0009    0.0006    0.0004    0.0003
Atlantic Spotted Dolphin........    0.0000    0.0000    0.0000    0.0001    0.0004    0.0006    0.0005    0.0008    0.0043    0.0068    0.0017    0.0002
Atlantic White-Sided Dolphin....    0.0263    0.0158    0.0111    0.0169    0.0369    0.0380    0.0204    0.0087    0.0193    0.0298    0.0225    0.0321
Bottlenose Dolphin, Offshore....    0.0051    0.0012    0.0008    0.0022    0.0097    0.0163    0.0177    0.0200    0.0198    0.0181    0.0160    0.0129
Common Dolphin..................    0.0933    0.0362    0.0320    0.0474    0.0799    0.1721   0.01549    0.2008    0.3334    0.3331    0.1732    0.1467
Pilot Whales....................    0.0029    0.0029    0.0029    0.0029    0.0029    0.0029    0.0029    0.0029    0.0029    0.0029    0.0029    0.0029
Risso's Dolphin.................    0.0005    0.0001    0.0000    0.0003    0.0014    0.0010    0.0013    0.0028    0.0035    0.0017    0.0015    0.0020
Harbor Porpoise.................    0.1050    0.1135    0.1081    0.0936    0.0720    0.0174    0.0174    0.0156    0.0165    0.0203    0.0219    0.0675
Gray Seal.......................    0.0594    0.0585    0.0419    0.0379    0.0499    0.0075    0.0019    0.0016    0.0028    0.0064    0.0246    0.0499
Harbor Seal.....................    0.1335    0.1314    0.0941    0.0850    0.1120    0.0167    0.0043    0.0037    0.0063    0.0145    0.0552    0.1120
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Listed as Endangered under the ESA.
\1\ Densities were calculated using the 2022 Duke Habitat-Based Marine Mammal Density Models (Roberts et al., 2016; 2023).

    As previously discussed, SouthCoast's ITA application includes 
installation of up to 147 WTG foundations and up to 5 OSP foundations 
in 149 positions within the Lease Area. However, for the purposes of 
exposure modeling, SouthCoast assumed installation of two OSPs (one per 
Project), each supported by a piled jacket foundation secured by 12 to 
16 pin piles.

                                   Table 31--Foundation Installation Scenarios
----------------------------------------------------------------------------------------------------------------
                                Method: impact    WTG foundation  WTG foundation   OSP pin pile
           Scenario              or vibratory          type           number          number        Piling days
----------------------------------------------------------------------------------------------------------------
                                                    Project 1
----------------------------------------------------------------------------------------------------------------
Scenario 1...................  Impact..........  Monopile.......              71              12              59
Scenario 2...................  Impact..........  Jacket.........              85              16              85
----------------------------------------------------------------------------------------------------------------
                                                    Project 2
----------------------------------------------------------------------------------------------------------------
Scenario 1...................  Impact..........  Monopile.......              68              12              53
Scenario 2...................  Both............  Monopile.......              73              12              49
Scenario 3...................  Both............  Jacket.........              62              16              62
----------------------------------------------------------------------------------------------------------------

    SouthCoast calculated take estimates for all five foundation 
installation scenarios presented in their application, based on modeled 
exposures and other relevant data (e.g., PSO date, mean group sizes). 
Tables 32-36 provide the results of marine mammal exposure modeling, 
which assumes 10-dB attenuation and seasonal restrictions, for each 
scenario. The Level A harassment exposure estimates represent animats 
that exceeded the PTS SELcum thresholds as this metric was exceeded 
prior to exceeding PTS SPLpeak thresholds The Level B 
harassment exposure estimates shown for Project 1 Scenarios 1 and 2, 
and Project 2 Scenario 1 represent animats exceeding the unweighted 160 
dB SPLrms criterion because impact pile driving would be the 
only installation method in these scenarios. The Level B harassment 
exposure estimates shown for Project 2 Scenarios 2 and 3 (tables 32-36) 
represent animats exceeding the unweighted 120 dB SPLrms 
and/or 160 dB SPLrms criteria because these scenarios 
require both vibratory and impact pile driving. Columns 4 and 5 in 
tables 32-36 show what the take estimates would be if the PSO data or 
average group size, respectively, were used to inform the number of 
proposed takes by Level B harassment in lieu of the density and 
exposure modeling. The last column represents the total Level B 
harassment take estimate for each species, based on the highest of the 
three estimates (density-based exposures, PSO data, or average group 
size).
    Below we present the exposure estimates and the take estimates for 
these scenarios (Tables 32-36). For Project 1, no single scenario 
results in a greater amount of take for all species; therefore, the 
maximum annual and 5-year total amount of take proposed for 
authorization is a combination of both scenarios depending on species 
(i.e., the scenario which resulted in the greatest amount of take was 
carried forward for each species). For Project 2, Scenario 2 results in 
the greatest amount of take for all species and is carried forward in 
the maximum annual and 5-year total amount of take proposed for 
authorization.

[[Page 53770]]



Table 32--Project 1 Scenario 1 (P1S1): Estimated Level A Harassment \1\ and Level B Harassment \2\ Take From Installation of 71 WTG Monopile Foundations
                                            and 12 OSP Jacket Pin Piles, Assuming 10 dB of Noise Attenuation
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Level A         Level B
                                                            harassment      harassment                                       Estimated       Estimated
                         Species                             exposure        exposure      PSO data take    Mean group        level A         level B
                                                           modeling take   modeling take     estimate          size         harassment      harassment
                                                           estimate P1S1   estimate P1S1                                     take P1S1       take P1S1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale *............................................             N/A             N/A  ..............             1.0               0               1
Fin whale *.............................................            13.2            38.8             3.4             1.8              14              39
Humpback whale..........................................             9.3            28.4            32.4             2.0              10              33
Minke whale.............................................            45.7           168.6             6.4             1.4              46             169
North Atlantic right whale *............................             2.1             8.8  ..............             2.4               3               9
Sei whale *.............................................             1.3             4.7             0.9             1.6               2               5
Atlantic spotted dolphin................................             0.0           22.71  ..............            29.0               0              29
Atlantic white-sided dolphin............................             0.0           520.8  ..............            27.9               0             521
Bottlenose dolphin......................................             0.0           267.4            84.2            12.3               0             268
Common dolphin..........................................             0.0         6,975.3           735.6            34.9               0           6.976
Harbor porpoise.........................................             0.0           312.2             0.1             2.7               0             313
Pilot whales............................................             0.0            60.7             3.7            10.3               0              61
Risso's dolphin.........................................             0.0            36.5  ..............             5.4               0              37
Sperm whale *...........................................             0.0            12.4             0.3             2.0               0              13
Gray seal...............................................             0.1           209.6             2.0             1.4               1             210
Harbor seal.............................................             0.0            15.1            30.5             1.4               1              31
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.
\1\ Level A harassment take estimates assumes no implementation of monitoring and mitigation measures beyond 10-dB attenuation using a Noise Mitigation
  System, and seasonal restrictions.
\2\ Level B harassment take estimates are based on distances to the unweighted 120 dB threshold for vibratory pile driving and 160 dB threshold for
  impact pile driving.


    Table 33--Project 1 Scenario 2 (P1S2): Estimated Level A Harassment \1\ and Level B Harassment \2\ Take From Installation of 85 Piled Jacket WTG
                                       Foundations and 16 OSP Jacket Pin Piles Assuming 10 dB of Noise Attenuation
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Level A         Level B
                                                            harassment      harassment                                       Estimated       Estimated
                         Species                             exposure        exposure      PSO data take    Mean group        level A         level B
                                                           modeling take   modeling take     estimate          size         harassment      harassment
                                                           estimate P1S2   estimate P1S2                                     take P1S2       take P1S2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale *............................................             N/A             N/A  ..............             1.0               0               1
Fin whale *.............................................            10.3            22.4             3.8             1.8              11              23
Humpback whale..........................................            11.7            28.4            37.0             2.0              12              37
Minke whale.............................................            45.6           196.1             7.3             1.4              46             197
North Atlantic right whale *............................             3.9            12.0  ..............             2.4               4              12
Sei whale *.............................................             2.3             6.1             1.0             1.6               3               7
Atlantic spotted dolphin................................             0.0            24,4  ..............            29.0               0              29
Atlantic white-sided dolphin............................             0.0           727.1  ..............            27.9               0             728
Bottlenose dolphin......................................             0.0           303.5            96.0            12.3               0             304
Common dolphin..........................................             0.0         8.552.1           839.2            34.9               0           8,553
Harbor porpoise.........................................             0.0           377.3             0.2             2.7               0             378
Pilot whales............................................             0.0            39.8             4.2            10.3               0              40
Risso's dolphin.........................................             0.0            29.1  ..............             5.4               0              30
Sperm whale *...........................................             0.0            10.0             0.3             2.0               0              10
Gray seal...............................................             0.2           224.9             2.3             1.4               1             225
Harbor seal.............................................             0.0            25.8            34.8             1.4               0              35
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.
\1\ Level A harassment take estimates assumes no implementation of monitoring and mitigation measures beyond 10-dB attenuation using a Noise Mitigation
  System, and seasonal restrictions.
\2\ Level B harassment take estimates are based on distances to the unweighted 120 dB threshold for vibratory pile driving and 160 dB threshold for
  impact pile driving.


[[Page 53771]]


Table 34--Project 2 Scenario 1 (P2S1): Estimated Level A Harassment \1\ and Level B Harassment \2\ Take From Installation of 68 Monopile WTG Foundations
                                             and 12 OSP Jacket Pin Piles Assuming 10 dB of Noise Attenuation
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Level A         Level B
                                                            harassment      harassment                                       Estimated       Estimated
                         Species                             exposure        exposure      PSO data take    Mean group        level A         level B
                                                           modeling take   modeling take     estimate          size         harassment      harassment
                                                           estimate P2S1   estimate P2S1                                     take P2S1       take P2S1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale *............................................             N/A             N/A  ..............             1.0               0               1
Fin whale *.............................................            11.0            31.9             3.2             1.8              11              32
Humpback whale..........................................             9.7            28.8            31.1             2.0              10              32
Minke whale.............................................            45.0           163.9             6.2             1.4              46             164
North Atlantic right whale *............................             2.2             9.1  ..............             2.4               3              10
Sei whale *.............................................             1.5             5.2             0.8             1.6               2               6
Atlantic spotted dolphin................................             0.0           26.05  ..............            29.0               0              29
Atlantic white-sided dolphin............................             0.0           550.1  ..............            27.9               0             551
Bottlenose dolphin......................................             0.0           249.7            80.6            12.3               0             250
Common dolphin..........................................             0.0         6,912.3           704.5            34.9               0           6,913
Harbor porpoise.........................................             0.0           304.3             0.1             2.7               0             305
Pilot whales............................................             0.0            57.5             3.5            10.3               0              58
Risso's dolphin.........................................             0.0            31.9  ..............             5.4               0              32
Sperm whale *...........................................             0.0            10.4             0.3             2.0               0              11
Gray seal...............................................             0.1           234.1             1.9             1.4               1             235
Harbor seal.............................................             0.0            16.9            29.2             1.4               1              30
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.
\1\ Level A harassment take estimates assumes no implementation of monitoring and mitigation measures beyond 10-dB attenuation using a Noise Mitigation
  System, and seasonal restrictions.
\2\ Level B harassment take estimates are based on distances to the unweighted 120 dB threshold for vibratory pile driving and 160 dB threshold for
  impact pile driving.


Table 35--Project 2 Scenario 2 (P2S2): Estimated Level A Harassment \1\ and Level B Harassment \2\ Take From Installation of 73 Monopile WTG Foundations
                                             and 12 OSP Jacket Pin Piles Assuming 10 dB of Noise Attenuation
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Level A         Level B
                                                            harassment      harassment                                       Estimated       Estimated
                         Species                             exposure        exposure      PSO data take    Mean group        level A         level B
                                                           modeling take   modeling take     estimate          size         harassment      harassment
                                                           estimate P2S2   estimate P2S2                                     take P2S2       take P2S2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale *............................................             N/A             N/A  ..............             1.0               0               1
Fin whale *.............................................            14.3           482.0             7.2             1.8              15             481
Humpback whale..........................................            10.7           282.0            69.9             2.0              11             282
Minke whale.............................................            49.6           868.2            13.9             1.4              50             869
North Atlantic right whale *............................             2.3           100.0  ..............             2.4               3             100
Sei whale *.............................................             1.4            41.9             1.9             1.6               2              42
Atlantic spotted dolphin................................             0.0          319.59  ..............            29.0               0             320
Atlantic white-sided dolphin............................             0.0         3,045.0  ..............            27.9               0           3,045
Bottlenose dolphin......................................             0.0         2,341.1           181.4            12.3               0           2,342
Common dolphin..........................................             0.0        41,092.2         1,585.1            34.9               0          41,093
Harbor porpoise.........................................             0.0         2,381.3             0.3             2.7               0           2,382
Pilot whales............................................             0.0           634.0             8.0            10.3               0             635
Risso's dolphin.........................................             0.0         1,759.8  ..............             5.4               0           1,760
Sperm whale *...........................................             0.0           121.4             0.6             2.0               0             122
Gray seal...............................................             0.2         8,330.8             4.3             1.4               1           8,331
Harbor seal.............................................             0.0           432.0            65.8             1.4               1             432
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.
\1\ Level A harassment take estimates assumes no implementation of monitoring and mitigation measures beyond 10-dB attenuation using a Noise Mitigation
  System, and seasonal restrictions.
\2\ Level B harassment take estimates are based on distances to the unweighted 120 dB threshold for vibratory pile driving and 160 dB threshold for
  impact pile driving.


[[Page 53772]]


    Table 36--Project 2 Scenario 3 (P2S3): Estimated Level A Harassment \1\ and Level B Harassment \2\ Take From Installation of 62 Piled Jacket WTG
                                       Foundations and 16 OSP Jacket Pin Piles Assuming 10 dB of Noise Attenuation
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Level A         Level B
                                                            harassment      harassment                                       Estimated       Estimated
                         Species                             exposure        exposure      PSO data take    Mean group        level A         level B
                                                           modeling take   modeling take     estimate          size         harassment      harassment
                                                           estimate P2S3   estimate P2S3                                     take P2S3       take P2S3
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale *............................................             N/A             N/A  ..............             1.0               0               1
Fin whale *.............................................             8.1           113.0             3.4             1.8               9             113
Humpback whale..........................................             8.7            97.7            32.4             2.0               9              98
Minke whale.............................................            34.9           491.1             6.4             1.4              35             492
North Atlantic right whale *............................             3.1            40.0  ..............             2.4               4              40
Sei whale *.............................................             1.7            18.0             0.9             1.6               2              19
Atlantic spotted dolphin................................             0.0           74.62  ..............            29.0               0              75
Atlantic white-sided dolphin............................             0.0         1,647.5  ..............            27.9               0           1,648
Bottlenose dolphin......................................             0.0           829.5            84.2            12.3               0             830
Common dolphin..........................................             0.0        20,176.9           735.6            34.9               0          20,177
Harbor porpoise.........................................             0.0         1,001.1             0.1             2.7               0           1,002
Long-finned pilot whale.................................             0.0           195.0             3.7            10.3               0             195
Risso's dolphin.........................................             0.0           135.7  ..............             5.4               0             136
Sperm whale *...........................................             0.0            35.1             0.3             2.0               0              36
Gray seal...............................................             0.3           992.8             2.0             1.4               1             993
Harbor seal.............................................             0.0            70.2            30.5             1.4               0              71
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.
\1\ Level A harassment take estimates assumes no implementation of monitoring and mitigation measures beyond 10-dB attenuation using a Noise Mitigation
  System, and seasonal restrictions.
\2\ Level B harassment take estimates are based on distances to the unweighted 120 dB threshold for vibratory pile driving and 160 dB threshold for
  impact pile driving.

    The model-based Level A harassment (PTS) exposure estimates are 
conservative in that they assume no mitigation measures other than 10 
dB of sound attenuation and seasonal restrictions. Although the 
enhanced mitigation and monitoring measures SouthCoast proposed (see 
Proposed Mitigation and Proposed Monitoring and Reporting sections 
below) are specifically focused on reducing pile-driving impacts on 
North Atlantic right whales, other marine mammal species would 
experience conservation benefits as well (e.g., extended seasonal 
restrictions, increased monitoring effort and larger minimum visibility 
zone improving detectability and mitigation efficacy, extended pile-
driving delays (24-48 hrs) if a North Atlantic right whale is 
detected). When implemented, the additional mitigation measures 
described in the Proposed Mitigation section, including soft-start and 
clearance/shutdown processes, would reduce the already very low 
probability of Level A harassment. Additionally, modeling does not 
include any avoidance behavior by the animals, yet we know many marine 
mammals avoid areas of loud sounds. Thus, it is unlikely that an animal 
would remain within the Level A harassment SELcum zone long 
enough to incur PTS and could potentially redirect their movements away 
from the pile installation location in response to the soft-start 
procedure. For these reasons, SouthCoast is not requesting Level A 
harassment (PTS) take incidental to foundation installation for most 
marine mammal species, even though animal movement modeling estimated 
that a small number of PTS exposures could occur for multiple species 
(as shown in tables 32-36). In the case of North Atlantic right whales, 
the potential for Level A harassment (PTS) has been determined to be 
reduced to a de minimis likelihood due to the enhanced mitigation and 
monitoring measures, which include even larger clearance and shutdown 
zones (see Proposed Mitigation and Proposed Monitoring and Reporting 
sections). SouthCoast did not request, and NMFS is not proposing to 
authorize, take by Level A harassment of North Atlantic right whales.
    However, as a precautionary measure, because the WTG and OSP 
foundation installation Level A harassment ER95 
distances for fin whales are, in some cases, substantially larger than 
for other mysticete whales, Level A harassment take is being requested 
for this species. The second largest mysticete Level A harassment 
ER95 distance was selected as the clearance/shutdown 
zone size for baleen whales to avoid Level A harassment take of other 
mysticete species. SouthCoast assumed that the large clearance/shutdown 
zone size along with the soft-start procedure and potential for animal 
aversion to loud sounds would prevent Level A harassment take of other 
species. In most installation scenarios, 15-20 percent of the fin whale 
Level A harassment ER95 zone extends beyond the 
planned clearance/shutdown distance for non-NARW baleen whales, 
therefore, the requested Level A take for fin whales incidental to 
foundation installation is 20 percent of the fin whale Level A exposure 
estimates produced by the exposure modeling (Project 1 = 14; Project 2 
= 15). This results in a request for 3 Level A harassment takes for fin 
whales for both Project 1 and Project 2 (total of 6 across Projects). 
Table 37 shows the requested take incidental to foundation installation 
that is included in the total take NMFS proposes to authorize.
    For Project 1, no single scenario resulted in a greater amount of 
take for all species; therefore, the annual Level B harassment take 
numbers carried forward in table 37 reflect the maximum take estimate 
for each species between the two possible foundation installation 
scenarios (P1S1 and P1S2). Similarly for Project 2, the number of 
species-specific Level B harassment takes in table 37 reflects the 
maximum take estimate among the three analyzed scenarios (P2S1, P2S2, 
P2S3) which, in all cases, resulted from installations of P2S2. 
However, the 5-year total take incidental to foundation installation 
proposed for authorization for a given species (shown

[[Page 53773]]

in the last two columns in table 37) is less than the direct sum across 
Projects 1 and 2 values in the columns to the left. This is because the 
total number of takes must be based on a realistic construction 
scenario sequence that does not include take estimates resulting from 
modeling of installation of more than 149 foundations. For example, the 
number of estimated sei whale Level B harassment takes in column 3 of 
table 37 resulted from modeling installation of Project 1 Scenario 2 
(85 WTG foundations) and the number in column 5 resulted from modeling 
installation of Project 2 Scenario 2 (73 WTG foundations), representing 
take incidental to installation of a number of WTG foundations (158) 
larger than the maximum in SouthCoast's PDE (147). As described 
previously, some combinations of Project 1 and 2 scenarios are not 
possible because they would exceed the number of foundation positions 
available. However, SouthCoast indicates that the scenario chosen for 
Project 2 is dependent on the scenario installed for Project 1, which 
is uncertain at this time. Given this uncertainty, SouthCoast considers 
each of the five installation scenarios (Project 1, Scenarios 1 or 2; 
Project 2, Scenarios 1-3) described in table 2 possible. To ensure the 
total take proposed for authorization is based on a realistic number of 
foundations, the 5-year total is based on installation of Project 1 
Scenario 1 and Project 2 Scenario 2 (146 total foundations). This 
ensures that the take proposed for authorization for Project 2 
represents the maximum possible yearly take among the three scenarios 
considered for Project 2 as it is estimated using the largest potential 
ensonified zone (resulting from vibratory pile driving) and that 
sufficient take is requested for the full buildout. SouthCoast also 
considers the combination of Project 1 Scenario 2 and Project 2 
Scenario 3 (147 total foundations) a realistic construction plan. 
However, the 5-year take request is based on Project 1 Scenario 1 
combined with Project 2 Scenario 2 because it reflects a realistic 
construction plan that results in the greatest number of estimated 
takes.

       Table 37--Level A Harassment (PTS) and Level B Harassment Take Incidental to WTG and OSP Foundation Installation Proposed To Be Authorized
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                    SouthCoast requested and NMFS proposed take
                                                         -----------------------------------------------------------------------------------------------
                                                            Project 1--maximum between       Project 2--maximum among        Total based on realistic
                                                           scenarios 1-2 (P1S1 and P1S2)  scenarios 1-3 (P2S1, P2S2, and     combination of project 1
                         Species                         --------------------------------              P1S2)                 scenario 1 and project 2
                                                                                         --------------------------------           scenario 2
                                                              Level A         Level B                                    -------------------------------
                                                            harassment      harassment        Level A         Level B         Level A         Level B
                                                                                            harassment      harassment      harassment      harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale *............................................  ..............               1  ..............               1  ..............               2
Fin whale *.............................................               3              39               3             481               6             520
Humpback whale..........................................  ..............              37  ..............             282  ..............             315
Minke whale.............................................  ..............             197  ..............             869  ..............           1,038
North Atlantic right whale *............................  ..............              12  ..............             100  ..............             109
Sei whale *.............................................  ..............               7  ..............              42  ..............              47
Atlantic spotted dolphin................................  ..............              29  ..............             320  ..............             349
Atlantic white-sided dolphin............................  ..............             728  ..............           3,045  ..............           3,566
Bottlenose dolphin......................................  ..............             304  ..............           2,342  ..............           2,610
Common dolphin..........................................  ..............           8,553  ..............          41,093  ..............          48,069
Harbor porpoise.........................................  ..............             378  ..............           2,382  ..............           2,695
Pilot whales............................................  ..............              61  ..............             635  ..............             696
Risso's dolphin.........................................  ..............              37  ..............           1,760  ..............           1,797
Sperm whale *...........................................  ..............              13  ..............             122  ..............             135
Gray seal...............................................  ..............             225  ..............           8,331  ..............           8,451
Harbor seal.............................................  ..............              35  ..............             432  ..............             463
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.

UXO/MEC Detonation

    SouthCoast may detonate up to 5 UXO/MECs within the Lease Area and 
5 within the ECCs (10 UXOs/MECs total) over the 5-year effective period 
of the proposed rule. Charge weights of 2.3 kgs (2.2 lbs), 9.1 kgs 
(20.1 lbs), 45.5 kgs (100 lbs), 227 kgs (500 lbs), and 454 kgs (1,001 
lbs), were modeled to determine acoustic ranges to mortality, 
gastrointestinal injury, lung injury, PTS, and TTS thresholds. To do 
this, the source pressure function used for estimating peak pressure 
level and impulse metrics was calculated with an empirical model that 
approximates the rapid conversion of solid explosive to gaseous form in 
a small bubble under high pressure, followed by exponential pressure 
decay as that bubble expands (Hannay and Zykov, 2022). This initial 
empirical model is only valid close to the source (within tens of 
meters), so alternative formulas were used beyond those distances to a 
point where the sound pressure decay with range transitions to the 
spherical spreading model. The SEL thresholds occur at distances of 
many water depths in the relatively shallow waters of the Project 
(Hannay and Zykov, 2022). As a result, the sound field becomes 
increasingly influenced by the contributions of sound energy reflected 
from the sea surface and sea bottom multiples times. To account for 
this, propagation modeling was carried out in decidecade frequency 
bands using JASCO's MONM. This model applies a parabolic equation 
approach for frequencies below 4 kHz and a Gaussian beam ray trace 
model at higher frequencies (Hannay and Zykov, 2022). In SouthCoast 
project's location, sound speed profiles generally change little with 
depth, so these environments do not have strong seasonal dependence 
(see Figure 2 in the SouthCoast Underwater Acoustic Modeling of UXO/MEC 
report). The propagation modeling for UXO/MEC detonations was performed 
using an average sound speed profile for ``September'', which is 
slightly downward refracting. Please see

[[Page 53774]]

the supplementary report for SouthCoast's ITA application titled 
``Underwater Acoustic Modeling of Detonations of Unexploded Ordnance 
(UXO/MEC removal) for Mayflower Wind Farm Construction,'' found on 
NMFS' website (https://www.fisheries.noaa.gov/action/incidental-take-authorization-SouthCoast-wind-llc-construction-and-operation-SouthCoast-wind) for more technical details about the modeling methods, 
assumptions and environmental parameters used as inputs (Hannay and 
Zykov, 2022).
    The exact type and net explosive weight of UXO/MECs that may be 
detonated are not known at this time; however, they are likely to fall 
into one of the bins identified in table 38. To capture a range of UXO/
MECs, five categories or ``bins'' of net explosive weight, established 
by the U.S. Navy (2017a), were selected for acoustic modeling (table 
38).

    Table 38--Navy ``Bins'' and Corresponding Maximum Charge Weights
                        (Equivalent TNT) Modeled
------------------------------------------------------------------------
                                              Maximum
          Navy bin designation              equivalent     Weight (TNT)
                                               (kg)            (lbs)
------------------------------------------------------------------------
E4......................................             2.3               5
E6......................................             9.1              20
E8......................................            45.5             100
E10.....................................             227             500
E12.....................................             454           1,000
------------------------------------------------------------------------

    These charge weights were modeled at five different locations and 
associated depths located within the Lease Area and ECCs. Two sites are 
located in the Lease Area, S1 (60 m (196.9 ft)) and S2 (45 m (147.6 
ft)). Three sites are located within the ECCs, one along the western 
ECC (S3, 30 m) and two along the eastern ECC (S4, 20m (65.6 ft); S5, 10 
m (32.8 ft))). Sites 1 and 2 were deemed to be representative of the 
Lease Area and Sites 3-5 were deemed representative of the ECCs where 
detonations could occur (see Figure 1 in Hannay and Zykov, 2022). Exact 
locations for the modeling sites are shown in Figure 1 of Hannay and 
Zykov (2022).
    All distances to isopleths modeled can be found in Hannay and Zykov 
(2022). It is not currently known how easily SouthCoast would be able 
to identify the size and charge weights of UXOs/MECs in the field. 
Therefore, NMFS has proposed to require SouthCoast to implement 
mitigation measures assuming the largest E12 charge weight as a 
conservative approach. As such, distances to PTS (tables 39 and 40) and 
TTS thresholds (tables 41 and 42) for only the 454 kg (1,001 lbs) UXO/
MEC are presented, as this size UXO/MEC has the greatest potential for 
these impacts and is what is used to estimate take. NMFS notes that it 
is extremely unlikely that all 10 of the UXO/MECs found and requiring 
detonation for the SouthCoast Project would consist of this 454 kg 
(1,001 lbs) charge weight. If SouthCoast is able to reliably 
demonstrate that they can easily and accurately identify charge weights 
in the field, NMFS will consider mitigation and monitoring zones based 
on UXO/MEC charge weight for the final rulemaking rather than assuming 
the largest charge weight in every situation.
    To further reduce impacts to marine mammals, SouthCoast would 
deploy a NAS (a DBBC, at minimum) during every detonation event, 
similar to that described for foundation installation, with the 
expectation that their selected system would be able to achieve 10-dB 
attenuation. This expectation is based on an assessment of UXO/MEC 
clearance activities in European waters as summarized by Bellman and 
Betke (2021). NMFS would require SouthCoast to deploy NAS(s) (a dBBC, 
at minimum) during all denotations, thus it was deemed appropriate to 
apply attenuation R95% distances to determine the size of the 
ensonified zone for take estimation.
    Given the impact zone sizes and the required mitigation and 
monitoring measures, neither mortality nor non-auditory injury are 
considered likely to result from the activity. NMFS does not expect or 
propose to authorize any non-auditory injury, serious injury, or 
mortality of marine mammals from UXO/MEC detonation. The modeled 
distances, assuming 10 dB of sound attenuation, to the mortality 
threshold for all UXO/MECs sizes for all animal masses for the ECCs and 
Lease Area are small (i.e., 28-368 m (91.9 ft-1,207.4 ft); see Tables 
40-44 in SouthCoast's supplemental UXO/MEC modeling report; Hannay and 
Zykov, 2022), as compared to the distance/area that can be effectively 
monitored. The modeled distances to non-auditory injury thresholds 
range from 67-694 m (219.8-2,276.9 ft), assuming 10 dB of sound 
attenuation (see Tables 35-39 in SouthCoast's supplemental UXO/MEC 
modeling report; Hannay and Zykov, 2022). SouthCoast would be required 
to conduct extensive monitoring using both PSOs and PAM operators and 
clear an area of marine mammals prior to any detonation of UXOs/MECs. 
Given that SouthCoast would be employing multiple platforms to visually 
monitor marine mammals as well as passive acoustic monitoring, it is 
reasonable to assume that marine mammals would be reliably detected 
within approximately 700 m (2,296.59 ft) of the UXO/MEC being 
detonated, the potential for mortality or non-auditory injury is de 
minimis. SouthCoast did not request, and NMFS is not proposing to 
authorize, take by mortality or non-auditory injury. For this reason, 
we are not presenting all modeling results here; however, they can be 
found in SouthCoast's UXO/MEC acoustic modeling report (Hannay and 
Zykov, 2022).
    To estimate the maximum ensonified zones that could result from 
UXO/MEC detonations, the largest acoustic ranges 
(R95; assuming 10-dB attenuation) to PTS and TTS 
thresholds for the E12 UXO/MEC charge weight were used as radii to 
calculate the area of a circle (pi x r\2\; where r is the range to the 
threshold level) for each marine mammal hearing group. The largest 
range for the Lease Area from Sites 1 and 2 (S1 and S2) is shown in 
tables 39 and 41 and for the ECCs the largest range from Sites 3-5 (S3, 
S4, and S5) is shown in tables 40 and 42. These results represent the 
largest area potentially ensonified above the PTS and TTS threshold 
levels from a single detonation within the SouthCoast ECCs (tables 40 
and 42) and Lease Area (tables 39 and 41).

[[Page 53775]]



Table 39--Largest SEL-Based R95 PTS-Onset Ranges (in Meters) Sites S1-S2 (Lease Area) Modeled During UXO/
                                 MEC Detonation, Assuming 10-dB Sound Reduction
----------------------------------------------------------------------------------------------------------------
                                                                   Distance (m) to PTS threshold
                                        Representative site used  during E12 (454 kg) detonation      Maximum
      Marine mammal hearing group             for modeling       --------------------------------   ensonified
                                                                       Rmax         R95    zone (km\2\)
----------------------------------------------------------------------------------------------------------------
Low-Frequency Cetaceans...............  Site S1.................           4,490           4,300            58.1
Mid-Frequency Cetaceans...............  Site S2.................             349             322             0.3
High-frequency cetaceans..............  Site S1.................           9,280           8,610             233
Phocid pinnipeds (in water)...........  Site S1.................           1,680           1,560             7.6
----------------------------------------------------------------------------------------------------------------
\1\ For each hearing group, a given range (R95 or Rmax) reflects the modeling result for S1 or S2,
  whichever value was largest.


 Table 40--Largest SEL-Based R95 PTS-Onset Ranges (in Meters) Sites S3-S5 (ECCs) Modeled During UXO/MEC
                                   Detonation, Assuming 10-dB Sound Reduction
----------------------------------------------------------------------------------------------------------------
                                                                   Distance (m) to PTS threshold
                                        Representative site used  during E12 (454 kg) detonation      Maximum
      Marine mammal hearing group             for modeling       --------------------------------   ensonified
                                                                       Rmax         R95    zone (km\2\)
----------------------------------------------------------------------------------------------------------------
Low-frequency cetaceans...............  Site S5.................           5,830           4,840            73.6
Mid-frequency cetaceans...............  Site S5.................             659             597             1.1
High-frequency cetaceans..............  Site S3.................           8,190           7,390             172
Phocid pinnipeds (in water)...........  Site S5.................           2,990           2,600            21.2
----------------------------------------------------------------------------------------------------------------
\1\ For each hearing group, a given range (R95 or Rmax) reflects the modeling result for S3, S4, or S5,
  whichever value was largest.


   Table 41--Largest SEL-Based R95 TTS-Onset Ranges (in Meters) From Sites S1-S2 (Lease Area) Modeled
                            During UXO/MEC Detonation, Assuming 10-dB Sound Reduction
----------------------------------------------------------------------------------------------------------------
                                                                   Distance (m) to TTS threshold
                                        Representative site used  during E12 (454 kg) detonation      Maximum
      Marine mammal hearing group             for modeling       --------------------------------   ensonified
                                                                       Rmax         R95    zone (km\2\)
----------------------------------------------------------------------------------------------------------------
Low-frequency cetaceans...............  Site S2.................          13,200          11,900             445
Mid-frequency cetaceans...............  Site S1.................           2,820           2,550            20.4
High-frequency cetaceans..............  Site S1.................          15,400          14,100             625
Phocid pinnipeds (in water)...........  Site S2.................           7,610           6,990             154
----------------------------------------------------------------------------------------------------------------
\1\ For each hearing group, a given range (R95 or Rmax) reflects the modeling result for S1 or S2,
  whichever value was largest.


Table 42--Largest SEL-Based R95 TTS-Onset Ranges (In Meters) From Sites S3-S5 (ECCs) Modeled During UXO/
                                 MEC Detonation, Assuming 10-dB Sound Reduction
----------------------------------------------------------------------------------------------------------------
                                                                   Distance (m) to TTS threshold
                                        Representative site used  during E12 (454 kg) detonation      Maximum
      Marine mammal hearing group             for modeling       --------------------------------   ensonified
                                                                       Rmax         R95    zone (km\2\)
----------------------------------------------------------------------------------------------------------------
Low-frequency cetaceans...............  Sites S4 and S5.........          13,500          11,800             437
Mid-frequency cetaceans...............  Site S3.................           2,820           2,480            19.3
High-frequency cetaceans..............  Site S4 and S5..........          15,600          13,700             589
Phocid pinnipeds (in water)...........  Sites S4 and S5.........           7,820           7,020             155
----------------------------------------------------------------------------------------------------------------
\1\ For each hearing group, a given range (R95 or Rmax) reflects the modeling result for S3, S4, or S5,
  whichever value was largest.

    To avoid any in situ detonations of UXO/MECs during periods when 
North Atlantic right whale densities are highest in and near the ECCs 
and Lease Area, this activity would be restricted from December 1 
through April 30, annually. Accordingly, for each species, they 
selected the highest average monthly density between May and November 
and assumed all 10 UXO/MECs would be detonated in that month to 
conservatively estimate exposures from UXO/MEC detonation for a given 
species in any given year. Given UXO/MECs detonations have the 
potential to occur anywhere within the Lease Area and ECCs, a 15-km 
(9.3-mi) perimeter was applied around the Lease and, separately, the 
ECCs to define the area over which densities would be evaluated. As 
described above, in the case of blue whales and pilot whales, monthly 
densities were unavailable; therefore, annual densities were used 
instead.
    Table 43 provides those densities and the associated months in 
which the species-specific densities are highest for the Lease Area and 
ECCs.

[[Page 53776]]



  Table 43--Maximum Average Monthly Marine Mammal Densities (Individuals/km\2\) Within 15 km of the SouthCoast
    Project ECCs and Lease Area From May Through November, and the Month in Which the Maximum Density Occurs
----------------------------------------------------------------------------------------------------------------
                                                     ECCs                                Lease area
                                   -----------------------------------------------------------------------------
                                        Maximum
                                        average
              Species                   monthly                                Maximum        Maximum average
                                        density     Maximum density month      density        monthly density
                                     (individual/                                            (individual/km\2\)
                                        km\2\)
----------------------------------------------------------------------------------------------------------------
Blue whale *......................          0.0000  Annual...............          0.0000  Annual
Fin whale *.......................          0.0013  May..................          0.0047  July
Humpback whale....................          0.0012  May..................          0.0035  June
Minke whale.......................          0.0107  May..................          0.0175  June
North Atlantic right whale *......          0.0022  May..................          0.0037  May
Sei whale *.......................          0.0007  May..................          0.0019  May
Atlantic spotted dolphin..........          0.0002  September............          0.0068  October
Atlantic white-sided dolphin......          0.0102  May..................          0.0380  June
Bottlenose dolphin................          0.0042  August...............          0.0200  August
Common dolphin....................          0.0335  November.............          0.3334  September
Harbor porpoise...................          0.0284  May..................          0.0720  May
Pilot whales......................          0.0002  Annual...............          0.0029  Annual
Risso's dolphin...................          0.0004  November.............          0.0035  September
Sperm whale *.....................          0.0003  August...............          0.0017  August
Grey seal.........................          0.1051  May..................          0.0499  May
Harbor seal.......................          0.2362  May..................          0.1120  May
----------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.

    Based on the available information, up to five UXO/MEC detonations 
may be necessary in the ECCs and up to five in the Lease Area (10 UXO/
MEC detonations total). To estimate take incidental to UXO/MEC 
detonations in the SouthCoast ECCs, the maximum ensonified areas based 
on the largest R95% to Level A harassment (PTS) and Level B 
harassment (TTS) thresholds (assuming 10-dB attenuation) from a single 
detonation (assuming the largest UXO/MEC charge weight) in the ECC, as 
shown in tables 40 and 42, were multiplied by three (the maximum number 
of UXOs/MECs that are expected to be detonated in the SouthCoast ECC in 
Year 1 of construction) and two (the maximum number of UXOs/MECs that 
are expected to be detonated in the SouthCoast ECC in Year 2 of 
construction). The results were then multiplied by the marine mammal 
densities shown in table 43, resulting in the exposures estimates in 
table 44. The division of five total detonations within the ECCs across 
the two years was based on the relative number of foundations to be 
installed in each year. The same method was applied using the maximum 
single detonation areas shown in table 39 and table 41 to calculate the 
potential take from UXO/MEC detonations in the Lease area. The 
resulting density-based take estimates for all 10 UXO/MEC detonations 
are summarized in table 44. Table 52 in SouthCoast's application 
provides annual take estimates separately for each of the two years 
during which UXO/MEC detonations may occur.
    As shown below in table 44, the likelihood of marine mammal 
exposures above the PTS threshold is low, especially considering the 
instantaneous nature of the acoustic signal and the fact that there 
will be no more than 10 UXO/MECs detonated throughout the effective 
period of the authorization. Further, NMFS is proposing mitigation and 
monitoring measures intended to minimize the potential for PTS for most 
marine mammal species, and the extent and severity of behavioral 
harassment (TTS), including: (1) time of year/seasonal restrictions; 
(2) time of day restrictions; (3) use of PSOs to visually observe for 
North Atlantic right whales; (4) use of PAM to acoustically detect 
North Atlantic right whales; (5) implementation of clearance zones; (6) 
use of noise mitigation technology; and, (7) post-detonation monitoring 
visual and acoustic monitoring by PSOs and PAM operators (see Proposed 
Mitigation and Proposed Monitoring and Reporting sections below). 
However, given the relatively large distances to the high-frequency 
cetacean Level A harassment (PTS, SELcum) isopleth 
applicable to harbor porpoises and the difficulty detecting this 
species at sea, NMFS is proposing to authorize 109 Level A harassment 
takes of harbor porpoise from UXO/MEC detonations. Similarly, seals are 
difficult to detect at longer ranges, and although the distances to the 
phocid hearing group SEL PTS threshold are not as large as those for 
high-frequency cetaceans, it may not be possible to detect all seals 
within the PTS threshold distances even with the proposed monitoring 
measures. Therefore, NMFS is proposing to authorize 40 Level A 
harassment takes of gray seals and 4 Level A harassment takes of harbor 
seals incidental to UXO/MEC detonation. Although exposure modeling 
resulted in small numbers of estimated Level A harassment (PTS) 
exposures for large whales (i.e., fin, humpback, minke, North Atlantic, 
and sei whales), NMFS anticipates that implementation of the mitigation 
and monitoring measures described above will reduce the potential for 
Level A harassment to discountable amounts.

[[Page 53777]]



                 Table 44--Level A Harassment (PTS) and Level B Harassment (TTS, Behavior) Estimated Take Incidental to UXO/MEC Detonations \1\ Assuming 10-dB Noise Attenuation
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                     Total level  Total level  Total level  Total level
                                                                      A density    B density    A density    B density                         Requested    Requested    Requested    Requested
                                                                        based        based        based        based       PSO data    Mean     level A      level B      level A      level B
                       Marine mammal  species                          exposure     exposure     exposure     exposure       take      group      take         take         take         take
                                                                       estimate     estimate     estimate     estimate     estimate    size    project 1    project 1    project 2    project 2
                                                                      project 1    project 1    project 2    project 2                            \2\                       \2\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale *.......................................................          0.0          0.0          0.0          0.0  ...........     1.0            0            1            0            1
Fin whale *........................................................          1.1         12.5          0.7          8.3          0.5     1.8            0           13            0            9
Humpback whale.....................................................          0.9          9.2          0.6          6.1          4.6     2.0            0           10            0            7
Minke whale........................................................          5.5         46.4          3.6         30.9          0.9     1.2            0           47            0           31
North Atlantic right whale *.......................................          1.1          9.9          0.7          6.6  ...........     2.4            0           10            0            7
Sei whale *........................................................          0.5          5.1          0.3          3.4  ...........     1.6            0            6            0            4
Atlantic spotted dolphin...........................................          0.0          0.8          0.0          0.6  ...........    29.0            0           29            0           29
Atlantic white-sided dolphin.......................................          0.0          4.5          0.0          3.1  ...........    27.9            0           28            0           28
Bottlenose dolphin.................................................          0.0          2.4          0.0          1.6         11.9     7.8            0           13            0           13
Common dolphin.....................................................          0.4         39.7          0.3         26.5        103.6    34.9            0          104            0          104
Harbor porpoise....................................................         64.9        262.3         43.2        174.8          0.0     2.7           65          263           44          175
Pilot whales.......................................................          0.0          0.4          0.0          0.2          0.5     8.4            0           11            0           11
Risso's dolphin....................................................          0.0          0.4          0.0          0.2  ...........     5.4            0            6            0            6
Sperm whale *......................................................          0.0          0.2          0.0          0.2          0.0     1.5            0            2            0            2
Gray seal..........................................................         23.9        140.6         15.9         93.8          0.1     1.4           24          141           16           94
Harbor seal........................................................          1.5          9.1          1.1          6.1          0.2     1.4            2           10            2            7
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.
\1\ SouthCoast expects up to 10 UXO/MECs will necessitate high-order removal (detonation), and anticipates that 5 of these would be found in the Lease Area, and 5 would be found in the export
  cable corridors.
\2\ Although UXO/MEC exposure modeling estimated potential Level A harassment (PTS) exposures for mysticete whales, SouthCoast did not request Level A harassment for these species given the
  assumption that their proposed monitoring and mitigation measures would prevent this form of take incidental to UXO/MEC detonations.

HRG Surveys

    SouthCoast's proposed HRG survey activity includes the use of 
impulsive (i.e., boomers and sparkers) and non-impulsive (e.g., CHIRP 
SBPs) sources (table 45).

 Table 45--Representative HRG Survey Equipment and Operating Frequencies
------------------------------------------------------------------------
                                                             Operating
         Equipment type               Representative         frequency
                                     equipment model           (kHz)
------------------------------------------------------------------------
Sub-bottom Profiler............  Teledyne Benthos Chirp              2-7
                                  III--TTV 170.
Sparker........................  Applied Acoustics Dura-        0.01-1.9
                                  Spark UHD (400 tips,
                                  800 J).
Boomer.........................  Applied Acoustics                 0.1-5
                                  triple plate S-Boom
                                  (700 J).
------------------------------------------------------------------------

    Authorized takes would be by Level B harassment only in the form of 
disruption of behavioral patterns for individual marine mammals 
resulting from exposure to noise from certain HRG acoustic sources. 
Based primarily on the characteristics of the signals produced by the 
acoustic sources planned for use, Level A harassment is neither 
anticipated, even absent mitigation, nor proposed for authorization. 
Therefore, the potential for Level A harassment is not evaluated 
further. Please see SouthCoast's application for details of a 
quantitative exposure analysis (i.e., calculated distances to Level A 
harassment isopleths and Level A harassment exposures). No serious 
injury or mortality is anticipated to result from HRG survey 
activities.
    In order to better account for the narrower and directional beams 
of the sources, NMFS has developed a tool, specific to HRG surveys, for 
determining the sound pressure level (SPLrms) at the 160-dB 
isopleth for the purposes of estimating the extent of Level B 
harassment isopleths associated with HRG survey equipment (NMFS, 2020). 
This methodology incorporates frequency-dependent absorption and some 
directionality to refine estimated ensonified zones. SouthCoast used 
NMFS' methodology with additional modifications to incorporate a 
seawater absorption formula and account for energy emitted outside of 
the primary beam of the source. For sources that operate with different 
beamwidths, the maximum beam width was used, and the lowest frequency 
of the source was used when calculating the frequency-dependent 
absorption coefficient.
    NMFS considers the data provided by Crocker and Fratantonio (2016) 
to represent the best scientific information available on source levels 
associated with HRG equipment and therefore, recommends that source 
levels provided by Crocker and Fratantonio (2016) be incorporated in 
the method described above to estimate ranges to the Level A harassment 
and Level B harassment isopleths. In cases when the source level for a 
specific type of HRG equipment is not provided in Crocker and 
Fratantonio (2016), NMFS recommends that either the source levels 
provided by the manufacturer be used or in instances where source 
levels provided by the manufacturer are unavailable or unreliable, a 
proxy from Crocker and Fratantonio (2016) be used instead. SouthCoast 
utilized the NMFS User Spreadsheet Tool (NMFS, 2018), following these 
criteria for selecting the appropriate inputs:
    (1) For equipment that was measured in Crocker and Fratantonio 
(2016), the reported SL for the most likely operational parameters was 
selected.

[[Page 53778]]

    (2) For equipment not measured in Crocker and Fratantonio (2016), 
the best available manufacturer specifications were selected. Use of 
manufacturer specifications represent the absolute maximum output of 
any source and do not adequately represent the operational source. 
Therefore, they should be considered an overestimate of the sound 
propagation range for that equipment.
    (3) For equipment that was not measured in Crocker and Fratantonio 
(2016) and did not have sufficient manufacturer information, the 
closest proxy source measured in Crocker and Fratantonio (2016) was 
used.
    The Teledyne Benthos Chirp III has the highest source level, so it 
was also selected as a representative sub-bottom profiling system in 
table 45. Crocker and Fratantonio (2016) measured source levels of a 
device similar to the Teledyne Benthos Chirp III TTV 170 towfish, the 
Knudsen 3202 Chirp sub-bottom profiler, at several different power 
settings. The highest power settings measured for the Knudsen 3202 were 
determined to be applicable to a hull-mounted Teledyne Benthos Chirp 
III system, while the lowest power settings were determined to be 
applicable to the towfish version of the Teledyne Benthos Chirp III 
that may be used by SouthCoast. The EdgeTech Chirp 512i measurements 
and specifications provided by Crocker and Fratantonio (2016) were used 
as a proxy for both the Edgetech 3100 with SB-216 towfish and EdgeTech 
DW-106, given its similar operations settings. The EdgeTech Chirp 424 
source levels were used as a proxy for the Knudsen Pinger sub-bottom 
profiler. The sparker systems that may be used during the HRG surveys, 
the Applied Acoustics Dura-Spark and the Geomarine Geo-Spark, were 
measured by Crocker and Fratantonio (2016) but not with an energy 
setting near 800 Joules (J). A similar alternative system, the SIG ELC 
820 sparker,measured with an input voltage of 750 J, was used as a 
proxy for both the Applied Acoustics Dura-Spark UHD (400 tips, 800 J) 
and Geomarine Geo-Spark (400 tips, 800 J), and was conservatively 
assumed to be an omnidirectional source.
    Table 46 identifies all the representative survey equipment that 
operates below 180 kHz (i.e., at frequencies that are audible and have 
the potential to disturb marine mammals) that may be used in support of 
planned survey activities and are likely to be detected by marine 
mammals given the source level, frequency, and beamwidth of the 
equipment. This table also provides all operating parameters used to 
calculate the distances to threshold for marine mammals.

                                    Table 46--Summary of Representative HRG Survey Equipment and Operating Parameters
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                   Source
                                                                      Operating     level       Source      Pulse    Repetition   Beamwidth  Information
             Equipment type                 Representative model      frequency    SPLrms     level0-pk    duration   rate (Hz)   (degrees)     source
                                                                        (kHz)       (dB)         (dB)        (ms)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sub-bottom Profiler....................  EdgeTech 3100 with SB-216         2-16        179          184          10         9.1          51           CF
                                          \1\ towfish.
                                         EdgeTech DW-106 \1\.......         1-6        176          183        14.4          10          66           CF
                                         Knudson Pinger \2\........          15        180          187           4           2          71           CF
                                         Teledyne Benthos CHIRP             2-7        199          204          10        14.4          82           CF
                                          III--TTV 170 \3\.
Sparker \4\............................  Applied Acoustics Dura-       0.01-1.9        203          213         3.4           2        Omni           CF
                                          Spark UHD (400 tips, 800
                                          J).
                                         Geomarine Geo-Spark (400      0.01-1.9        203          213         3.4           2        Omni           CF
                                          tips, 800 J).
Boomer.................................  Applied Acoustics triple         0.1-5        205          211         0.9           3          61           CF
                                          plate S-Boom (700 J).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: J = joule; kHz = kilohertz; dB = decibels; SL = source level; UHD = ultra-high definition; rms = root-mean square; [micro]Pa = microPascals; re =
  referenced to; SPL = sound pressure level; PK = zero-to-peak pressure level; Omni = omnidirectional source; CF = Crocker and Fratantonio (2016).
\1\ The EdgeTech Chirp 512i measurements and specifications provided by Crocker and Fratantonio (2016) were used as a proxy for the Edgetech 3100 with
  SB-216 towfish and EdgeTech DW-106.
\2\ The EdgeTech Chirp 424 measurements and specifications provided by Crocker and Fratantonio (2016) were used as a proxy for the Knudsen Pinger SBP.
\3\ The Knudsen 3202 Echosounder measurements and specifications provided by Crocker and Fratantonio (2016) were used as a proxy for the Teledyne
  Benthos Chirp III TTV 170.
\4\ The SIG ELC 820 Sparker, 5 m source depth, 750 J setting was used as a proxy for both the Applied Acoustics Dura-Spark UHD (400 tips, 800 J) and
  Geomarine Geo-Spark (400 tips, 800 J).

    Results of modeling using the methodology described above indicated 
that, of the HRG equipment planned for use by SouthCoast that has the 
potential to result in Level B harassment of marine mammals, sound 
produced by the Geomarine Geo-Spark and Applied Acoustics Dura-Spark 
would propagate furthest to the Level B harassment isopleth (141 m 
(462.6 ft); table 47). For the purposes of take estimation, it was 
conservatively assumed that sparkers would be the dominant acoustic 
source for all survey days (although, again, this may not always be the 
case). Thus, the range to the isopleth corresponding to the threshold 
for Level B harassment for and the boomer and sparkers (141 m (462.6 
ft)) was used as the basis of take calculations for all marine mammals. 
This is a conservative approach as the actual sources used on 
individual survey days or during a portion of a survey day may produce 
smaller distances to the Level B harassment isopleth.

      Table 47--Distances to the Level B Harassment Thresholds for
 Representative HRG Sound Source or Comparable Sound Source Category For
                    Each Marine Mammal Hearing Group
------------------------------------------------------------------------
                                                              Level B
                                                            harassment
                                                           threshold (m)
         Equipment type            Representative model  ---------------
                                                           All (SPLrms)
 
------------------------------------------------------------------------
Sub-bottom Profiler............  Edgetech 3100 with SB-                4
                                  216.
                                 towfish................
                                 EdgeTech DW-106 \1\....               3
                                 Knudson Pinger \2\.....               6
                                 Teledyn Benthos CHIRP                66
                                  III--TTV 170 \3\.

[[Page 53779]]

 
Sparker........................  Applied Acoustics Dura-             141
                                 Spark UHD..............
                                 400 tips (800 J).......
                                 Geomarine Geo-Spark                 141
                                  (400 tips, 800 J).
Boomer.........................  Applied Acoustics                    90
                                  triple plate S-Boom
                                  (700-1,000 J).
------------------------------------------------------------------------

    To estimate species densities for the HRG surveys occurring both 
within the Lease Area and within the ECCs based on Roberts et al. 
(2016; 2023), a 5-km (3.11 mi) perimeter was applied around each area 
(see Figures 14 and 15 of SouthCoast's application) using GIS (ESRI, 
2017). Given that HRG surveys could occur at any point year-round and 
is likely to be spread out throughout the year, the annual average 
density for each species was calculated using average monthly densities 
from January through December (table 48).

 Table 48--Annual Average Marine Mammal Densities Along the Export Cable
                 Corridors and SouthCoast Lease Area \1\
------------------------------------------------------------------------
                                            ECCs annual     Lease Area
                                              average     Annual Average
          Marine mammal species               density         density
                                            (individual     (individual
                                            per km\2\)      per km\2\)
------------------------------------------------------------------------
Blue whale *............................          0.0000          0.0000
Fin whale *.............................          0.0008          0.0022
Humpback whale..........................          0.0007          0.0016
Minke whale.............................          0.0029          0.0057
North Atlantic right whale *............          0.0023          0.0027
Sei whale *.............................          0.0003          0.0006
Atlantic spotted dolphin................          0.0000          0.0013
Atlantic white-sided dolphin............          0.0050          0.0231
Bottlenose dolphin......................          0.0023          0.0116
Common dolphin..........................          0.0218          0.1503
Harbor porpoise.........................          0.0267          0.0557
Pilot whales............................          0.0002          0.0029
Risso's dolphin.........................          0.0002          0.0013
Sperm whale *...........................          0.0001          0.0005
Harbor seal.............................          0.1345          0.0641
Gray seal...............................          0.0599          0.0285
------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.

    The maximum range (141 m (462.6 ft)) to the Level B harassment 
threshold and the estimated trackline distance traveled per day by a 
given survey vessel (i.e., 80 km (50 mi)) were then used to calculate 
the daily ensonified area or zone of influence (ZOI) around the survey 
vessel.
    The ZOI is a representation of the maximum extent of the ensonified 
area around a HRG sound source over a 24-hr period. The ZOI for each 
piece of equipment operating at or below 180 kHz was calculated per the 
following formula:

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

Where r is the linear distance from the source to the harassment 
isopleth.
    The largest daily ZOI (22.6 km\2\ (8.7 mi\2\)), associated with the 
proposed use of sparkers, was applied to all planned survey days.
    During construction, SouthCoast estimated approximately a length of 
4,000 km (2,485.5 mi) of surveys would occur within the Lease Area and 
5,000 km (3,106.8 mi) would occur within the ECCs. Potential Level B 
density-based harassment exposures were estimated by multiplying the 
average annual density of each species within the survey area by the 
daily ZOI. That product was then multiplied by the number of planned 
survey days in each sector during the approximately 2-year construction 
timeframe (62.5 days in the ECCs and 50 days in the Lease Area), and 
the product was rounded to the nearest whole number. This assumed a 
total ensonified area of 1,130 km\2\ (702.1 mi\2\) in the Lease Area 
and 1,412.5 km\2\ (877.7 mi\2\) along the ECCs. The density-based 
modeled Level B harassment take for HRG surveys during the construction 
period assumes approximately 60 percent (5,400 km) and 40 percent 
(3,600 km) of track lines would be surveyed during Year 1 (associated 
with Project 1) and Year 2 (associated with Project 2), respectively. 
SouthCoast estimated a conservative number of annual takes by Level B 
harassment based on the highest predicted value among the density-
based, PSO data-derived, or average group size estimates. These results 
can be found in table 49.

[[Page 53780]]



                       Table 49--Estimated Level B Harassment Take Incidental to HRG Surveys During the 2-Year Construction Period
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                     Project 1 estimated take       Project 2 estimated                                         Highest
                                 --------------------------------          take              Total                              annual        Highest
                                                                 ------------------------  density-    PSO data   Mean group    Level B   Annual Level B
      Marine mammal species                                                               based take     take        size     harassment    harassment
                                      Lease area         ECCs     Lease area     ECCs      estimate    estimate                  take     take Project 2
                                                                                                                               Project 1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale *....................  0.0...............         0.0         0.0         0.0         0.0           -         1.0           1               1
Fin whale *.....................  1.2...............         0.6         1.3         0.6         3.6         5.3         1.8           6               6
Humpback whale..................  0.9...............         0.5         0.9         0.5         2.8        51.4         2.0          52              52
Minke whale.....................  3.2...............         2.0         3.3         1.7        10.5        10.2         1.4          11              11
North Atlantic right whale *....  1.5...............         1.6         1.5         1.7         6.3           -         2.4           4               4
Sei whale *.....................  0.3...............         0.2         0.4         0.2         1.1         1.4         1.6           2               2
Atlantic spotted dolphin........  0.7...............         0.0         0.7         0.0         1.5           -        29.0          29              29
Atlantic white-sided dolphin....  12.9..............         3.5        13.3         3.6        33.2           -        27.9          28              28
Bottlenose dolphin..............  6.5...............         1.6         6.7         1.7        16.4       133.4        12.3         134             134
Common dolphin..................  83.8..............        15.2        86.1        15.6       200.8      1165.5        34.9       1,166           1,166
Harbor porpoise.................  31.1..............        18.6        31.9        19.1       100.8         0.2         2.7          50              52
Pilot whales....................  1.6...............         0.1         1.7         0.1         3.6         5.9         8.4          11              11
Risso's dolphin.................  0.7...............         0.1         0.8         0.1           1           -         5.4           6               6
Sperm whale *...................  0.3...............         0.1         0.3         0.1         0.7         0.4         1.5           2               2
Gray seal.......................  48.5..............       127.2        49.8       130.8       355.6         3.1         1.4         176             181
Harbor seal.....................  3.1...............         8.3         3.2         8.5        23.1        48.3         1.4          49              49
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.
Note:-not applicable.

    As mentioned previously, HRG surveys would also routinely be 
carried out during the period following completion of foundation 
installations which, for the purposes of exposure modeling, SouthCoast 
assumed to be three years. Generally, SouthCoast followed the same 
approach as described above for HRG surveys occurring during the two 
years of construction activities, modified to account for reduced 
survey effort following foundation installation. During the three years 
when construction is not occurring, SouthCoast estimates that HRG 
surveys would cover 2,800 km (1,739.8 mi) within the Lease Area and 
3,200 km (1,988.4 mi) along the ECCs annually. Maintaining that 80 km 
(50 mi) are surveyed per day, this amounts to 35 days of survey 
activity in the Lease Area and 40 days of survey activity along the 
ECCs each year or 225 days total for the three-year timeframe following 
the two years of construction activities. Similar to the approach 
outlined above, density-based take was estimated by multiplying the 
daily ZOI by the annual average densities and the number of survey days 
planned for the ECCs and SouthCoast Lease Area. Using the same approach 
described above, SouthCoast estimated a conservative number of annual 
takes by Level B harassment based on the highest exposures predicted by 
the density-based, PSO based, or average group size-based estimates. 
The highest predicted take estimate was multiplied by three to yield 
the number of takes that is proposed for authorization, as shown in 
table 50 below.

             Table 50--Estimate Take, by Level B Harassment, Incidental to HRG Surveys During the 3 Years When Construction Would Not Occur
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                Annual operations phase                                                      Total Level
                                                                  take by survey area       Annual                                Highest         B
                                                              --------------------------    total      Annual PSO   Mean group     annual     harassment
                    Marine mammal species                                                  density-    data take       size       Level B    take over 3
                                                                Lease area      ECCs      based take    estimate                    take       years of
                                                                                           estimate                                          HRG surveys
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale *.................................................          0.0          0.0          0.0            -          1.0            1            3
Fin whale *..................................................          1.8          0.7          2.5          3.6          1.8            4           12
Humpback whale...............................................          1.3          0.6          1.9         34.3          2.0           35          105
Minke whale..................................................          4.5          2.6          7.1          6.8          1.4            8           24
North Atlantic right whale *.................................          2.1          2.1          4.2            -          2.4            5           15
Sei whale *..................................................          0.5          0.3          0.7          0.9          1.6            2            6
Atlantic spotted dolphin.....................................          1.0          0.0          1.1            -         29.0           29           87
Atlantic white-sided dolphin.................................         18.3          4.5         22.8            -         27.9           28           84
Bottlenose dolphin...........................................          9.2          2.1         11.3         88.9         12.3           89          267
Common dolphin...............................................        119.0         19.7        138.7        777.0         34.9          778        2,334
Harbor porpoise..............................................         44.1         24.2         68.3          0.1          2.7           69          207
Pilot whales.................................................          2.3          0.1          2.5          3.9         10.3           11           33
Risso's dolphin..............................................          1.1          0.1          1.2            -          5.4            6           18
Sperm whale *................................................          0.4          0.1          0.5          0.3          2.0            2            6
Gray seal....................................................         68.8        165.1        234.0          2.1          1.4          234          702
Harbor seal..................................................          4.5         10.7         15.2         32.2          1.4           33           99
--------------------------------------------------------------------------------------------------------------------------------------------------------
** Denotes species listed under the Endangered Species Act.
Note:-not applicable.


[[Page 53781]]

Total Proposed Take Across All Activities

    The species-specific numbers of annual take by Level A harassment 
and Level B harassment NMFS proposes to authorize incidental to all 
specified activities combined are provided in table 51. Take estimation 
assumed pile-driving noise will be attenuated by 10 dB and, where 
applicable, implementation of seasonal restrictions and clearance and 
shutdown processes to discount the potential for Level A harassment of 
most species for which it was estimated. NMFS also presents the 5-year 
total number of takes proposed for authorization for each species in 
table 52.
    Table 51 presents the annual take proposed for authorization, based 
on the assumption that specific activities would occur in particular 
years. SouthCoast currently plans to install all permanent structures 
(i.e., WTG and OSP foundations) within two of the five years of the 
proposed effective period, which includes a single year for Project 1 
and a single year for Project 2. However, foundation installations may 
not begin in the first year of the effective period of the rule or 
occur in sequential years, and NMFS acknowledges that construction 
schedules may shift. The proposed rule allows for this flexibility; 
however, the number of takes for each species in any given year must 
not exceed the maximum annual numbers provided in table 53.
    In table 51, years 1 and 2 represent the assumed years (for take 
estimation) in which SouthCoast would install WTG and OSP foundations. 
For each species, the Year 1 proposed take includes the highest take 
estimate between P1S1 and P1S2 for foundation installation, one year of 
HRG surveys, and five high-order detonations of the heaviest charge 
weight (E12) UXO/MECs (at a rate of one per day for up to five days). 
The proposed Level B harassment take for Year 2 is based on P2S2 for 
foundation installation, given it resulted in the highest Level B 
harassment take estimates among P2S1, P2S2, and P2S3 for all species 
because it includes vibratory (in addition to impact) pile driving of 
monopiles, one year of HRG surveys, and up to five high-order 
detonations of the heaviest charge weight (E12) UXO/MECs (also at a 
rate of one per day for up to five days). In table 51, take for years 
3-5 is incidental to HRG surveys. All activities with the potential to 
result in incidental take of marine mammals are expected to be 
completed by early 2031.
    In making the negligible impact determination, NMFS assesses both 
the maximum annual total number of takes (Level A harassment and Level 
B harassment) of each marine mammal species or stocks allowable in any 
one year, which in the case of this proposed rule is in Year 2, and the 
total taking of each marine mammal species or stock allowable during 
the 5-year effective period of the rule.
    NMFS has carefully considered all information and analysis 
presented by SouthCoast as well as all other applicable information 
and, based on the best scientific information available, concurs that 
the SouthCoast's estimates of the types and number of take for each 
species and stock are reasonable and, thus, NMFS is proposing to 
authorize the number requested.

    Table 51--Level A Harassment and Level B Harassment Takes of Marine Mammals Proposed To Be Authorized Incidental to All Activities During Construction and Development of the SouthCoast
                                                                                  Offshore Wind Energy Project
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                  Year 1                Year 2 \1\                Year 3                  Year 4                  Year 5
                                                                         -----------------------------------------------------------------------------------------------------------------------
                                                              NMFS stock    Level A                             Level B
                    Marine mammal species                      abundance  harassment    Level B     Level A   harassment    Level A     Level B     Level A     Level B     Level A     Level B
                                                                             (max     harassment  harassment     (max     harassment  harassment  harassment  harassment  harassment  harassment
                                                                            annual)                             annual)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale *................................................     \2\ 402           0           3           0           3           0           1           0           1           0           1
Fin whale *.................................................       6,802           3          58           3         496           0           4           0           4           0           4
Humpback whale..............................................       1,396           0          99           0         341           0          35           0          35           0          35
Minke whale.................................................      21,968           0         255           0         911           0           8           0           8           0           8
North Atlantic right whale *................................         338           0          26           0         111           0           5           0           5           0           5
Sei whale *.................................................       6,292           0          15           0          48           0           2           0           2           0           2
Atlantic spotted dolphin....................................      39,921           0          87           0         378           0          29           0          29           0          29
Atlantic white-sided dolphin................................      93,221           0         784           0       3,101           0          28           0          28           0          28
Bottlenose dolphin \3\......................................      62,851           0         451           0       2,489           0          89           0          89           0          89
Common dolphin..............................................     172,974           0       9,823           0      42,363           0         778           0         778           0         778
Harbor porpoise.............................................      95,543        * 65         691          44       2,609           0          69           0          69           0          69
Long-finned pilot whales \3\................................      39,215           0          83           0         657           0          11           0          11           0          11
Risso's dolphin.............................................      35,215           0          49           0       1,772           0           6           0           6           0           6
Sperm whale *...............................................       4,349           0          17           0         126           0           2           0           2           0           2
Gray seal...................................................      27,300        * 24         542          16       8,606           0         234           0         234           0         234
Harbor seal.................................................      61,336           2          94           2         488           0          33           0          33           0          33
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.


     Table 52--5-Year Total Level A Harassment and Level B Harassment Takes of Marine Mammals Proposed To Be
   Authorized Incidental to All Activities During Construction and Development of the SouthCoast Offshore Wind
                                                 Energy Project
----------------------------------------------------------------------------------------------------------------
                                                                                           5-Year totals
                                                                                 -------------------------------
                      Marine mammal species                         NMFS stock    Proposed Level
                                                                     abundance     A harassment   Proposed Level
                                                                                       take        B harassment
----------------------------------------------------------------------------------------------------------------
Blue whale *....................................................         \1\ 402               0               9
Fin whale *.....................................................           6,802               6             566
Humpback whale..................................................           1,396               0             541
Minke whale.....................................................          21,968               0           1,162

[[Page 53782]]

 
North Atlantic right whale *....................................             338               0             149
Sei whale *.....................................................           6,292               0              67
Atlantic spotted dolphin........................................          39,921               0             552
Atlantic white-sided dolphin....................................          93,233               0           3,762
Bottlenose dolphin..............................................          62,851               0           3,171
Common dolphin..................................................         172,974               0          52,943
Harbor porpoise.................................................          95,543             109           3,442
Long-finned pilot whales........................................          39,215               0             773
Risso's dolphin.................................................          35,215               0           1,839
Sperm whale *...................................................           4,349               0             149
Gray seal.......................................................          27,300              40           9,835
Harbor seal.....................................................          61,336               4             677
----------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.

    To inform both the negligible impact analysis and the small numbers 
determination, NMFS assesses the maximum number of takes of marine 
mammals that could occur within any given year. In this calculation, 
the maximum number of Level A harassment takes in any one year is 
summed with the maximum number of Level B harassment takes in any one 
year for each species to yield the highest number of estimated take 
that could occur in any year (table 53). Table 53 also depicts the 
number of takes relative to the abundance of each stock. The takes 
enumerated here represent daily instances of take, not necessarily 
individual marine mammals taken. One take represents a day (24-hour 
period) in which an animal was exposed to noise above the associated 
harassment threshold at least once. Some takes represent a brief 
exposure above a threshold, while in some cases takes could represent a 
longer, or repeated, exposure of one individual animal above a 
threshold within a 24-hour period. Whether or not every take assigned 
to a species represents a different individual depends on the daily and 
seasonal movement patterns of the species in the area. For example, 
activity areas with continuous activities (all or nearly every day) 
overlapping known feeding areas (where animals are known to remain for 
days or weeks on end) or areas where species with small home ranges 
live (e.g., some pinnipeds) are more likely to result in repeated takes 
to some individuals. Alternatively, activities far out in the deep 
ocean or takes to nomadic species where individuals move over the 
population's range without spatial or temporal consistency represent 
circumstances where repeat takes of the same individuals are less 
likely. In other words, for example, 100 takes could represent 100 
individuals each taken on 1 day within the year, or it could represent 
5 individuals each taken on 20 days within the year, or some other 
combination depending on the activity, whether there are biologically 
important areas in the project area, and the daily and seasonal 
movement patterns of the species of marine mammals exposed. Wherever 
there is information to better contextualize the enumerated takes for a 
given species is available, it is discussed in the Preliminary 
Negligible Impact Analysis and Determination and/or Small Numbers 
sections, as appropriate. We recognize that certain activities could 
shift within the 5-year effective period of the rule; however, the rule 
allows for that flexibility and the takes are not expected to exceed 
those shown in table 53 in any one year.
    Of note, there is significant uncertainty regarding the impacts of 
turbine foundation presence and operation on the oceanographic 
conditions that serve to aggregate prey species for North Atlantic 
right whales and--given SouthCoast's proximity to Nantucket Shoals--it 
is possible that the expanded analysis of turbine presence and/or 
operation over the life of the project developed for the ESA biological 
opinion for the proposed SouthCoast project or additional information 
received during the public comment period will necessitate 
modifications to this analysis. For example, it is possible that 
additional information or analysis could result in a determination that 
changes in the oceanographic conditions that serve to aggregate North 
Atlantic right whale prey may result in impacts that would qualify as a 
take under the MMPA for North Atlantic right whales.

 Table 53--Maximum Number of Proposed Takes (Level A Harassment and Level B Harassment) That Could Occur in Any
One Year of the Project Relative to Stock Population Size (Assuming Each Take Is of a Different Individual), and
                                          Total Take for 5-Year Period
----------------------------------------------------------------------------------------------------------------
                                                         Maximum annual \1\ take proposed to be authorized
                                                 ---------------------------------------------------------------
                                                                                                   Total percent
      Marine mammal species         NMFS stock                                                      stock taken
                                     abundance     Maximum Level   Maximum Level  Maximum annual     based on
                                                   A harassment    B harassment      take \4\     maximum annual
                                                                                                       take
----------------------------------------------------------------------------------------------------------------
Blue whale * \2\................         \1\ 402               0               3               3            0.75

[[Page 53783]]

 
Fin whale *.....................           6,802               3             496             499            7.34
Humpback whale..................           1,396               0             341             341            24.4
Minke whale.....................          21,968               0             911             911            4.15
North Atlantic right whale *....         \3\ 338               0             111             111            32.8
Sei whale *.....................           6,292               0              48              48            0.76
Atlantic spotted dolphin........          39,921               0             378             378            0.95
Atlantic white-sided dolphin....          93,221               0           3,101           3,101            3.33
Bottlenose dolphin,.............          62,851               0           2,489           2,489            3.96
Common dolphin..................         172,974               0          42,363          42,363            24.5
Harbor porpoise.................          95,543              65           2,609           2,674            2.80
Long-finned pilot whales........          68,139               0             657             657            0.96
Risso's dolphin.................          35,215               0           1,772           1,772            5.03
Sperm whale *...................           4,349               0             126             126            2.90
Gray seal.......................          27,300              24           8,606           8,630            31.6
Harbor seal.....................          61,336               2             488             490            0.80
----------------------------------------------------------------------------------------------------------------
* Denotes species listed under the Endangered Species Act.
\1\ The percent of stock impacted is the sum of the maximum number of Level A harassment takes in any year plus
  the maximum and Level B harassment divided by the stock abundance estimate then multiplied by 100. The best
  available stock abundance estimates are derived from the NMFS Stock Assessment Reports (Hayes et al., 2024).
  Year 2 has the maximum expected annual take authorized.
\2\ The minimum blue whale population is estimated at 402 (Hayes et al., 2024), although the exact value is not
  known. NMFS is utilizing this value for our small numbers determination.
\3\ NMFS notes that the 2022 North Atlantic Right Whale Annual Report Card (Pettis et al., 2023; n=340) is the
  same as the draft 2023 SAR (Hayes et al., 2024). While NMFS acknowledges the estimate found on the North
  Atlantic Right Whale Consortium's website (https://www.narwc.org/report-cards.html) matches, we have used the
  value presented in the draft 2023 SARs as the best available science for this final action (88 FR 5495,
  January 29, 2024, https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports; nmin=340).

Proposed Mitigation

    In order to promulgate a rulemaking under section 101(a)(5)(A) of 
the MMPA, NMFS must set forth the permissible methods of taking 
pursuant to the activity and other means of effecting the least 
practicable adverse impact on the species or stock and its habitat, 
paying particular attention to rookeries, mating grounds, and areas of 
similar significance and on the availability of the species or stock 
for taking for certain subsistence uses (latter not applicable for this 
action). NMFS' regulations require incidental take authorization 
applicants to include in their application information about the 
availability and feasibility (e.g., economic and technological) of 
equipment, methods, and manner of conducting the activity or other 
means of effecting the least practicable adverse impact upon the 
affected species or stocks and their habitat (50 CFR 216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, we 
carefully consider two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (e.g., likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented (i.e., 
probability of accomplishing the mitigating result if implemented as 
planned), the likelihood of effective implementation (i.e., probability 
if implemented as planned); and
    (2) The practicability of the measures for applicant 
implementation, which may consider factors, such as: cost, impact on 
operations, and, in the case of military readiness activities, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.
    The mitigation strategies described below are consistent with those 
required and successfully implemented under previous incidental take 
authorizations issued in association with in-water construction 
activities (e.g., soft-start, establishing shutdown zones). Additional 
measures have also been incorporated to account for the fact that the 
construction activities would occur offshore in an area that includes 
important marine mammal habitat. Modeling was performed to estimate 
Level A harassment and Level B harassment zone sizes, which were used 
to inform mitigation measures for the project's activities to minimize 
Level A harassment and Level B harassment to the extent practicable. 
Generally speaking, the proposed mitigation measures considered and 
required here fall into three categories: temporal (i.e., seasonal and 
daily) work restrictions, real-time measures (e.g., clearance, 
shutdown, and vessel strike avoidance), and noise attenuation/reduction 
measures. Temporal work restrictions are designed to avoid operations 
when marine mammals are concentrated or engaged in behaviors that make 
them more susceptible or make impacts more likely to occur. When 
temporal restrictions are in place, both the number and severity of 
potential takes, as well as both chronic (longer-term) and acute 
effects are expected to be reduced. Real-time measures, such as 
clearing an area of marine mammals prior to beginning activities or 
shutting down an activity if it is occuring, as

[[Page 53784]]

well as vessel strike avoidance measures, are intended to reduce the 
probability and severity of harassment by taking steps in real time 
once a higher-risk scenario is identified (e.g., once animals are 
detected within a harassment zone). Noise attenuation measures, such as 
bubble curtains, are intended to reduce the noise at the source, which 
reduces both acute impacts as well as the contribution to aggregate and 
cumulative noise that may result in long-term chronic impacts. Soft-
starts are another type of noise reduction measure in that animals are 
warned of the introduction of sound into their environment at lower 
levels before higher noise levels are produced. As a conservative 
measure applicable to all project activities and vessels, if a whale is 
observed or acoustically detected but cannot be confirmed as a species 
other than a North Atlantic right whale, SouthCoast must assume that it 
is a North Atlantic right whale and take the appropriate mitigation 
measures.
    Below, NMFS briefly describes the required training, coordination, 
and vessel strike avoidance measures that apply to all specified 
activities, and in the following subsections, we describe the measures 
that apply specifically to foundation installation, UXO/MEC 
detonations, and HRG surveys. Throughout, we also present enhanced 
mitigation measures specifically focused on reducing potential impacts 
of project activities on North Atlantic right whales given their 
population status and baseline conditions, as described in the 
Description of Marine Mammals in the Specified Geographic Area section. 
Details on specific mitigation requirements can be found in section 
217.334 of the proposed regulatory text below in Part 217--Regulations 
Governing The Taking And Importing Of Marine Mammals.

Training and Coordination

    NMFS requires all project employees and contractors conducting 
activities on the water, including but not limited to, all vessel 
captains and crew, to be trained in various marine mammal and 
regulatory requirements. All relevant personnel, including the marine 
mammal monitoring team(s), are required to participate in joint, 
onboarding training prior to the beginning of project activities. New 
relevant personnel (e.g., new PSOs, construction contractors, relevant 
crew) who join the project after work commences must also complete 
training before they begin work. The training must include review of, 
at minimum, marine mammal detection and identification methods, 
communication requirements and protocols, all required mitigation 
measures for each activity, including vessel strike avoidance measures, 
to minimize impacts on marine mammals and the authority of the marine 
mammal monitoring team(s). The training must support SouthCoast's 
compliance with these regulations and associated LOA if promulgated and 
issued. In addition, training would include information and resources 
available regarding applicable Federal laws and regulations for 
protected species. SouthCoast would provide documentation of training 
to NMFS prior to the start of in-water activities, and any time new 
personnel receive training.

Vessel Strike Avoidance Measures

    Implementation of the numerous vessel strike avoidance measures 
included in this rule is expected to reduce the risk of vessel strike 
to the degree that vessel strike would be avoided. While the likelihood 
of a vessel strike is generally low without these measures, vessel 
interaction is one of the most common ways that marine mammals are 
seriously injured or killed by human activities. Therefore, enhanced 
mitigation and monitoring measures are required to avoid vessel strikes 
to the extent practicable. While many of these measures are proactive, 
intending to avoid the heavy use of vessels during times when marine 
mammals of particular concern may be in the area, several are reactive 
and occur when Project personnel sight a marine mammal. The vessel 
strike avoidance mitigation requirements are described generally here 
and in detail in the proposed regulatory text in proposed section 
217.334(b)). SouthCoast Wind must comply with all vessel strike 
avoidance measures while in the specific geographic region unless a 
deviation is necessary to maintain safe maneuvering speed and justified 
because the vessel is in an area where oceanographic, hydrographic, 
and/or meteorological conditions severely restrict the maneuverability 
of the vessel; an emergency situation (as defined in the proposed 
regulatory text) presents a threat to the health, safety, life of a 
person; or when a vessel is actively engaged in emergency rescue or 
response duties, including vessel-in distress or environmental crisis 
response.
    While underway, SouthCoast Wind would be required to monitor for 
marine mammals and operate vessels in a manner that reduces the 
potential for vessel strike. SouthCoast must employ at least one 
dedicated visual observer (i.e., PSO or trained crew member) on each 
transiting vessel, regardless of speed or size. The dedicated visual 
observer(s) must maintain a vigilant watch for all marine mammals 
during transit and be equipped with suitable monitoring technology 
(e.g., binoculars, night vision devices) located at an appropriate 
vantage point. Any marine mammal detection by the observer (or anyone 
else on the vessel) must immediately be communicated to the vessel 
captain and any required mitigative action (e.g., reduce speed) must be 
taken.
    All of the project-related vessels would be required to comply with 
existing NMFS vessel speed restrictions for North Atlantic right whales 
and additional speed restriction measures within this rule. Reducing 
vessel speed is one of the most effective, feasible options available 
to reduce the likelihood of and effects from a vessel strike. Numerous 
studies have indicated that slowing the speed of vessels reduces the 
risk of lethal vessel collisions, particularly in areas where right 
whales are abundant and vessel traffic is common and otherwise 
traveling at high speeds (Vanderlaan and Taggart, 2007; Conn and 
Silber, 2013; Van der Hoop et al., 2014; Martin et al., 2015; Crum et 
al., 2019). In summary, all vessels must operate at 10 knots (18.5 km/
hr) or less when traveling from November 1 through April 30; in a SMA, 
DMA, Slow Zone; or when a North Atlantic right whale is observed or 
acoustically detected. Additionally, in the event that any project-
related vessel, regardless of size, observes any large whale (other 
than a North Atlantic right whale) within 500 m of an underway vessel 
or acoustically detected via the PAM system in the transit corridor, 
the vessel is required to immediately reduce speeds to 10 knots (18.5 
km/hr) or less and turn away from the animal until the whale can be 
confirmed visually beyond 500 m (1,640 ft) of the vessel.
    When vessel speed restrictions are not in effect and a vessel is 
traveling at greater than 10 knots 10 knots (18.5 km/hr) in addition to 
the required dedicated visual observer, SouthCoast would be required to 
monitor the vessel transit corridor(s) (the path(s) crew transfer 
vessels take from port to any work area) in real-time with PAM prior to 
and during transits. Should SouthCoast determine it may travel over 10 
knots (18.5 km/hr), it must submit a North Atlantic Right Whale Vessel 
Strike Avoidance Plan at least 180 days prior to transiting over 10 
knots (18.5 km/hr) which fully identifies the communication protocols 
and PAM system proposed for use. NMFS must

[[Page 53785]]

approve the plan before SouthCoast Wind can operate vessels over 10 
knots (18.5 km/hr).
    To monitor SouthCoast Wind's requirements with vessel speed 
restrictions, all vessels must be equipped with an AIS and SouthCoast 
Wind must report all Maritime Mobile Service Identify (MMSI) numbers to 
NMFS Office of Protected Resources prior to initiating in-water 
activities.
    In addition to speed restrictions, all project vessels, regardless 
of size, must maintain the following minimum separation distances 
between vessels and marine mammals: 500 m (1,640 ft) from North 
Atlantic right whale; 100 m (328 ft) from sperm whales and non-North 
Atlantic right whale baleen whales; and 50 m (164 ft) from all 
delphinid cetaceans and pinnipeds (an exception is made for those 
species that approach the vessel such as bow-riding dolphins) (table 
56). All reasonable steps must be taken to not violate minimum 
separation distances. If any of these species are sighted within their 
respective minimum separation zone, the underway vessel must turn away 
from the animal and shift its engine to neutral (if safe to do so) and 
the engines must not be engaged until the animal(s) have been observed 
to be outside of the vessel's path and beyond the respective minimum 
separation zone.

Seasonal and Daily Restrictions and Foundation Installation Sequencing

    Temporal restrictions in places where marine mammals are 
concentrated, engaged in biologically important behaviors, and/or 
present in sensitive life stages are effective measures for reducing 
the magnitude and severity of human impacts. NMFS is requiring temporal 
work restrictions to minimize the risk of noise exposure to North 
Atlantic right whales incidental to certain specified activities to the 
extent practicable. These temporal work restrictions are expected to 
greatly reduce the number of takes of North Atlantic right whales that 
would have otherwise occurred should all activities be conducted during 
these months. The measures proposed by SouthCoast Wind and those 
included in this rule are built around North Atlantic right whale 
protection; however, they also afford protection to other marine 
mammals that are known to use the project area with greater frequency 
during months when the restrictions would be in place, including other 
baleen whales.
    As described in the Description of Marine Mammals in the Specified 
Geographic Area section above, North Atlantic right whales may be 
present in the specified geographical region throughout the year. As it 
is not practicable to restrict activities year-round, NMFS evaluated 
the best scientific information available to identify temporal 
restrictions on foundation pile driving and UXO/MEC detonation that 
would ensure that the mitigation measures effect the least practicable 
adverse impact on marine mammals. First, NMFS evaluated density data 
(Roberts et al., 2023) which demonstrate that from June through 
October, the densities of North Atlantic right whales are expected to 
be an order of magnitude lower than those in November through May (see 
table 30 as an example). In addition, the number of DMAs, which are 
triggered by a sighting of three or more whales (and suggest foraging 
behavior may be taking place (Pace and Clapham, 2001)) also increase 
November through May. Additionally, the best available, recently 
published science indicates North Atlantic right whale presence is 
persistent beginning in late October through May (e.g., Davis et al., 
2023; van Parijs et al., 2023) (see Description of Marine Mammals in 
the Specified Geographic Area). NMFS and SouthCoast worked together to 
evaluate these multiple data sources in consideration of the modeling 
analysis and proximity to known high density areas of critical foraging 
importance in and around Nantucket Shoals to identify practicable 
temporal restrictions that affect the least practicable adverse impact 
on marine mammals. As described previously, no foundation pile driving 
would occur October 16-May 31 inside the NARW EMA or January 1-May 15 
throughout the rest of the Lease Area. Further, pile driving in 
December outside of the NARW EMA must not be planned (i.e., may only 
occur due to unforeseen circumstances, following approval by NMFS). 
Should NMFS approve December pile driving outside the NARW EMA, 
SouthCoast would be required to implement enhanced mitigation and 
monitoring measures to further reduce potential impacts to North 
Atlantic right whales as well as other marine mammal species.
    As described previously, the area in and around Nantucket Shoals is 
important foraging habitat for many marine mammal species. Therefore, 
SouthCoast Wind, in coordination with NMFS, has also proposed (and NMFS 
is proposing to require) that SouthCoast Wind sequence the installation 
of piles strategically. In the NARW EMA, SouthCoast would install 
foundations beginning June 1 in the northernmost positions, and 
sequence subsequent installations to the south/southwest such that 
foundation installation in positions closest to Nantucket Shoals would 
be completed during the period of lowest North Atlantic right whale 
occurrence in that area. NMFS would require SouthCoast to install the 
foundations as quickly as possible.
    With respect to diel restrictions, SouthCoast Wind has requested to 
initiate pile driving during night time. For nighttime pile driving to 
be approved, SouthCoast would be required to submit a Nighttime 
Monitoring Plan for NMFS' approval that reliably demonstrates the 
efficacy of their nighttime monitoring methods and systems and provides 
evidence that their systems are capable of detecting marine mammals, 
particularly large whales, at distances necessary to ensure that the 
required mitigation measures are effective. Should a plan not be 
approved, SouthCoast Wind would be restricted to initiating foundation 
pile driving during daylight hours, no earlier than 1 hour after civil 
sunrise and no later than 1.5 hours before civil sunset. Pile driving 
would be allowed to continue after dark when the installation of the 
same pile began during daylight (1.5 hours before civil sunset), when 
clearance zones were fully visible for at least 30 minutes or must 
proceed for human safety or installation feasibility reasons.
    There is no schedule for UXO/MEC detonations, as they would be 
considered on a case-by-case basis and only after all other means of 
removal have been exhausted. However, SouthCoast proposed a seasonal 
restriction on UXO/MEC detonations from December 1 through April 30 in 
both the Lease Area and ECCs to reduce impacts to North Atlantic right 
whales during peak occurrence periods. SouthCoast proposes to detonate 
no more than one UXO/MEC per 24-hr period. Moreover, detonations may 
only occur during daylight hours.
    Given the very small harassment zones resulting from HRG surveys 
and that the best available science indicates that any harassment from 
HRG surveys, should a marine mammal be exposed to sounds produced by 
the survey equipment (e.g., boomer), would most likely manifest as 
minor behavioral harassment only (e.g., potentially some avoidance of 
the HRG source), SouthCoast did not propose and NMFS is not proposing 
to require any seasonal and daily restrictions for HRG surveys.
    More information on activity-specific seasonal and daily 
restrictions can be found in the proposed regulatory text in proposed 
sections 217.334(c)(1) and 217.334(c)(2).

[[Page 53786]]

Noise Abatement Systems

    SouthCoast Wind would be required to employ noise abatement systems 
(NAS), also known as noise attenuation systems, during all foundation 
installations (i.e., during both vibratory and impact pile driving) and 
UXO/MEC detonations to reduce the sound pressure levels that are 
transmitted through the water in an effort to reduce ranges to acoustic 
thresholds and minimize any acoustic impacts, to the extent 
practicable, resulting from these activities.
    Two categories of NASs exist: primary and secondary. A primary NAS 
would be used to reduce the level of noise produced by foundation 
installation activities at the source, typically through adjustments on 
to the equipment (e.g., hammer strike parameters). Primary NASs are 
still evolving and would be considered for use during mitigation 
efforts when the NAS has been demonstrated as effective in commercial 
projects. However, as primary NASs are not fully effective at 
eliminating noise, a secondary NAS would be employed. The secondary NAS 
is a device or group of devices that would reduce noise as it was 
transmitted through the water away from the pile, typically through a 
physical barrier that would reflect or absorb sound waves and 
therefore, reduce the distance the higher energy sound propagates 
through the water column.
    Noise abatement systems, such as bubble curtains, are used to 
decrease the sound levels radiated from a source. Bubbles create a 
local impedance change that acts as a barrier to sound transmission. 
The size of the bubbles determines their effective frequency band, with 
larger bubbles needed for lower frequencies. There are a variety of 
bubble curtain systems, confined or unconfined bubbles, and some with 
encapsulated bubbles or panels. Attenuation levels also vary by type of 
system, frequency band, and location. Small bubble curtains have been 
measured to reduce sound levels but effective attenuation is highly 
dependent on depth of water, current, and configuration and operation 
of the curtain (Austin et al., 2016; Koschinski and L[uuml]demann, 
2013). Bubble curtains vary in terms of the sizes of the bubbles and 
those with larger bubbles tend to perform a bit better and more 
reliably, particularly when deployed with two separate rings (Bellmann, 
2014; Koschinski and L[uuml]demann, 2013; Nehls et al., 2016). 
Encapsulated bubble systems (e.g., Hydro Sound Dampers (HSDs)), can be 
effective within their targeted frequency ranges (e.g., 100-800 Hz), 
and when used in conjunction with a bubble curtain appear to create the 
greatest attenuation.
    The literature presents a wide array of observed attenuation 
results for bubble curtains. The variability in attenuation levels is 
the result of variation in design as well as differences in site 
conditions and difficulty in properly installing and operating in-water 
attenuation devices. D[auml]hne et al. (2017) found that single bubble 
curtains that reduce sound levels by 7 to 10 dB reduced the overall 
sound level by approximately 12 dB when combined as a double bubble 
curtain for 6-m steel monopiles in the North Sea. During installation 
of monopiles (consisting of approximately 8-m in diameter) for more 
than 150 WTGs in comparable water depths (>25 m) and conditions in 
Europe indicate that attenuation of 10 dB is readily achieved 
(Bellmann, 2019; Bellmann et al., 2020) using single BBCs for noise 
attenuation. While there are many assumptions that influence results of 
acoustic modeling (e.g., hammer energy, propagation), sound field 
verification measurements taken during construction of the South Fork 
Wind Farm and Vineyard Wind 1 wind farm indicate that it is reasonable 
to expect dual attenuation systems to achieve at least 10 dB sound 
attenuation.
    SouthCoast Wind would be required to use multiple NASs (e.g., 
double big bubble curtain (DBBC)) to ensure that measured sound levels 
do not exceed the levels modeled assuming a 10-dB sound level reduction 
for foundation installation and high-order UXO/MEC detonations, as well 
as implement adjustments to operational protocols (e.g., reduce hammer 
energy) to minimize noise levels. A single bubble curtain, alone or in 
combination with another NAS device, may not be used for either pile 
driving or UXO/MEC detonation as previously received sound field 
verification (SFV) data has revealed that this approach is unlikely to 
attenuate sounds to the degree that measured distances to harassment 
thresholds are equal to or smaller than those modeled assuming 10 dB of 
attenuation. Pursuant to the adaptive management provisions included in 
the proposed rule, should the research and development phase of newer 
attenuation systems demonstrate effectiveness, SouthCoast Wind may 
submit data on the efficacy of these systems and request approval from 
NMFS to use them during foundation installation and UXO/MEC detonation 
activities.
    Together, these systems must reduce noise levels to those not 
exceeding modeled ranges to Level A harassment and Level B harassment 
isopleths corresponding to those modeled assuming 10-dB sound 
attenuation, pending results of SFV; see the Sound Field Verification 
section below and Part 217--Regulations Governing The Taking And 
Importing Of Marine Mammals).
    When a double big bubble curtain is used (noting a single bubble 
curtain is not allowed), SouthCoast Wind would be required to maintain 
numerous operational performance standards. These standards are defined 
in the proposed regulatory text in proposed sections 217.334(c)(7) and 
217.334(d)(5) and include, but are not limited to, the requirements 
that construction contractors must train personnel in the proper 
balancing of airflow to the bubble ring and SouthCoast Wind must submit 
a performance test and maintenance report to NMFS within 72 hours 
following the performance test. Corrections to the attenuation device 
to meet regulatory requirements must occur prior to use during 
foundation installation activities and UXO/MEC detonation. In addition, 
a full maintenance check (e.g., manually clearing holes) must occur 
prior to each pile installation and UXO/MEC detonation. Should 
SouthCoast Wind identify that the NAS systems are not optimized, they 
would be required to make corrections to the NASs. The SFV monitoring 
and reporting requirements (see Proposed Monitoring and Reporting 
section) would be the means by which NMFS would determine if 
modifications to the NASs would be required. Noise abatement systems 
are not required during HRG surveys. A NAS cannot practicably be 
employed around a moving survey ship, but SouthCoast Wind would be 
required to make efforts to minimize source levels by using the lowest 
energy settings on equipment that has the potential to result in 
harassment of marine mammals (e.g., sparkers, CHIRPs, boomers) and 
turning off equipment when not actively surveying. Overall, minimizing 
the amount and duration of noise in the ocean from any of the project's 
activities through use of all means necessary and practicable will 
affect the least practicable adverse impact on marine mammals.

Clearance and Shutdown Zones

    NMFS requires the establishment of both clearance and, where 
technically feasible, shutdown zones during project activities that 
have the potential to result in harassment of marine mammals. The 
purpose of ``clearance'' of a particular zone is to minimize

[[Page 53787]]

potential instances of auditory injury and more severe behavioral 
disturbances by delaying the commencement of an activity if marine 
mammals are near the activity. The purpose of a shutdown is to prevent 
a specific acute impact, such as auditory injury or severe behavioral 
disturbance of sensitive species, by halting the activity.
    In addition to the zones described above, SouthCoast Wind would be 
required to establish a minimum visibility zone during pile driving to 
ensure that sighting conditions are sufficient for PSOs to visually 
detect marine mammals in the areas of highest potential impact. No 
minimum visibility zone would be required for UXO/MEC detonation as the 
entire visual clearance zone must be clearly visible, given the 
potential for lung and GI injury. Within the NARW EMA from August 1-
October 15 and outside the NARW EMA from May 16-31 and December 1-31, 
the minimum visibility zone sizes would be set equal to the largest 
Level B harassment zone (unweighted acoustic ranges to 160 dB re 1 
[mu]Pa sound pressure level) modeled for each pile type, assuming 10 dB 
of noise attenuation, rounded up to the nearest 0.1 km (0.06 mi) (7.5 
km (4.7 mi) monopiles; 4.9 km (3.0 mi) pin piles). For installations 
outside the NARW EMA from June 1-November 30, the minimum visibility 
zone would extend 3.7 km (2.3 mi) from the pile driving location (table 
54). This distance equals the second largest modeled 
ER95 distance to the Level A harassment isopleth 
(assuming 10 dB attenuation) among all marine mammals, rounded up to 
the closest 0.1 km (0.06 mi). The entire minimum visibility zone must 
be visible (i.e., not obscured by dark, rain, fog, etc.) for a full 60 
minutes immediately prior to commencing foundation pile driving. At no 
time would foundation pile driving be initiated when the minimum 
visibility zones cannot be fully visually monitored (using appropriate 
technology), as determined by the Lead PSO on duty.
    All relevant clearance and shutdown zones during project activities 
would be monitored by NMFS-approved PSOs and PAM operators (where 
required). Marine mammals may be detected visually or, in the case of 
pile driving and UXO/MEC detonation, acoustically. SouthCoast must 
design PAM systems to acoustically detect North Atlantic right whales 
to the identified PAM Clearance and Shutdown Zones (table 54). The PAM 
system must also be able to detect marine mammal vocalizations, 
maximize baleen whale detections, and be capable of detecting North 
Atlantic right whales to 10 km (6.2 km) and 15 km (9.3 mi), around pin 
piles and monopiles, respectively. NMFS recognizes that detectability 
of each species' vocalizations will vary based on vocalization 
characteristics (e.g., frequency content, source level), acoustic 
propagation conditions, and competing noise sources), such that other 
marine mammal species (e.g., harbor porpoise) may not be detected at 10 
km (6.2 mi) or 15 km (9.3 mi). and that, during pile driving, detecting 
marine mammals very close to the pile may be difficult due to masking 
from pile driving noise. Acoustic detections of any species would 
trigger mitigative action (delays or shutdown), when appropriate.
    Before the start of the specified activities (i.e., foundation 
installation, UXO/MEC detonation, and HRG surveys), SouthCoast Wind 
would be required to ensure designated areas (i.e., clearance zones as 
provided in tables 54-56) are clear of marine mammals to minimize the 
potential for and degree of harassment once the noise-producing 
activity begins. Immediately prior to foundation installation and UXO/
MEC detonations, PSOs and PAM operators would be required to begin 
visually and acoustically monitor clearance zones for marine mammals 
for a minimum of 60 minutes. For HRG surveys, PSOs would be required to 
monitor these zones for the 30 minutes directly before commencing use 
of boomers, sparkers, or CHIRPS. Clearance zones for all activities 
(i.e., foundation installation, UXO/MEC detonation, HRG surveys) must 
be confirmed to be free of marine mammals for 30-minutes immediately 
prior to commencing these activities, else, commencement of the 
activity must be delayed until the animal(s) has been observed exiting 
its respective zone or until an additional time period has elapsed with 
no further sightings. A North Atlantic right whale sighting at any 
distance by PSOs monitoring pile driving or UXO/MEC activities or 
acoustically detected within the PAM clearance zone (for pile driving 
or UXO/MEC detonations) would trigger a pile driving or detonation 
delay.
    In some cases, NMFS would require SouthCoast to implement extended 
pile driving delays to further reduce potential impacts to North 
Atlantic right whales utilizing habitat in the project area. As 
described previously, North Atlantic right whale occurrence in the 
project area remains low in June and July and begins to steadily 
increase from August through the fall, reaching maximum occurrence in 
winter, particularly in the portion of the lease area closest to 
Nantucket Shoals. For foundation installations in the NARW EMA from 
August 1-October 15 and throughout the remainder of the lease area May 
16-31 and December 1-31, annually, if a delay or shutdown is triggered 
by a sighting of less than three (i.e., one or two) North Atlantic 
right whales or an acoustic detection within the PAM clearance zone (10 
km (6.2 mi), pin piles; 15 km (9.3 mi), monopiles), SouthCoast would be 
required to delay commencement or resumption of pile driving 24 hours 
rather than after 60 minutes pass without additional sightings of the 
whale(s). While NMFS is requiring seasonal restrictions, there is 
potential for North Atlantic right whales to congregate in the project 
area when foundation pile driving activities are occuring. Data 
demonstrates these foraging aggregations are sporadic and dependent 
upon availability of prey, which is highly variable. For example, in 
August and October 2022, a total of 9 and 10 North Atlantic right 
whales, respectively, were sighted south of Nantucket (southeast of 
SouthCoast's Lease Area) over multiple days. In May 2023, 58 North 
Atlantic right whales were sighted southeast of Nantucket, although 
further to the east of the Lease Area than the 2022 sightings. The best 
available science demonstrates that when three or more North Atlantic 
right whales are observed, more often than not, they are both foraging 
and persisting in an area (Pace and Clapham, 2001). Therefore, for all 
foundation installations in the NARW EMA and those outside the NARW EMA 
from May 16-31 and December 1-31, annually, should PSOs sight three or 
more North Atlantic right whales in the same areas/times, SouthCoast 
would be required to delay pile driving for 48 hours. In both cases 
(i.e., 24- or 48-hour delay), NMFS would require that SouthCoast 
complete a vessel-based survey of the area around the pile driving 
location (10-km (6.2-mi) radius, pin piles; 15-km (9.3-mi) radius, 
monopiles) to ensure North Atlantic right whales are no longer in the 
project area before they could commence pile driving activities for the 
day.
    Once an activity begins, an observation of any marine mammal 
entering or within its respective shutdown zone (tables 54-56) would 
trigger cessation of the activity. In the case of pile driving, the 
shutdown requirement may be waived if is not practicable due to 
imminent risk of injury or loss of life to an individual, risk of 
damage to a vessel that creates risk of injury or loss of life for 
individuals, or where the lead engineer determines there is pile 
refusal or pile

[[Page 53788]]

instability. Because UXO/MEC detonations are instantaneous, no shutdown 
is possible; therefore, there are clearance, but no shutdown, zones for 
UXO/MEC detonations (table 55). In situations when shutdown is called 
for during foundation pile driving but SouthCoast Wind determines 
shutdown is not practicable due to any of the aforementioned emergency 
reasons, reduced hammer energy must be implemented when the lead 
engineer determines it is practicable. Specifically, pile refusal or 
pile instability could result in not being able to shut down pile 
driving immediately. Pile refusal occurs when a foundation pile 
encounters significant resistance or difficulty during the installation 
process. Pile instability occurs when the pile is unstable and unable 
to stay standing if the piling vessel were to ``let go.'' During these 
periods of instability, the lead engineer may determine a shut-down is 
not feasible because the shutdown combined with impending weather 
conditions may require the piling vessel to ``let go'' SouthCoast Wind 
would be required to document and report to NMFS all cases where the 
emergency exemption is taken.
    After shutdown, foundation installation may be reinitiated once all 
clearance zones are clear of marine mammals for the minimum species-
specific periods, or, if required to maintain pile stability, at which 
time the lowest hammer energy must be used to maintain stability. As 
described previously, for shutdowns triggered by observations of North 
Atlantic right whales, SouthCoast would not be able to resume pile 
driving until a survey of the 10-km (6.2-mi; for 4.5-m pin piles) or 
15-km (9.3-mi; for 9/16-m monopiles) zone surrounding the installation 
location is completed wherein no additional sightings occur. Upon re-
starting pile driving, soft-start protocols must be followed if pile 
driving has ceased for 30 minutes or longer.
    SouthCoast proposed equally-sized clearance and shutdown zones for 
pile driving, which are generally based on Level A harassment (PTS) 
ER95 distances, rounded up to the nearest 0.1 km 
(0.06 mi) for PSO clarity. For impact pile driving, the visual 
clearance and shutdown zones for large whales, other than North 
Atlantic right whales, correspond to the second largest modeled Level A 
harassment (PTS) exposure range (ER95) distance, 
assuming 10 dB attenuation.
    Clearance and shutdown zone sizes vary by activity and species 
groups. All distances to the perimeter of these zones are the radii 
from the center of the pile (table 54), UXO/MEC detonation location 
(table 55), or HRG acoustic source (table 56). Pursuant to the proposed 
adaptive management provisions, SouthCoast may request modification to 
these zone sizes (except for those that apply to North Atlantic right 
whales) as well as the minimum visibility zone, pending results of 
sound field verification (see Proposed Monitoring and Reporting 
section). Any changes to zone size would require NMFS' approval.

 Table 54--Clearance, Shutdown, and Minimum Visibility Zones, in Meters (m), During Sequential and Concurrent Installation of 9/16-m Monopiles and 4.5-m
                                                            Pin Piles in Summer (and Winter)
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
Installation order                                                                    Sequential
                                                                Concurrent
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pile type                                            9/16-m Monopile    4.5-m Pin pile     9/16-m Monopile
                                                              4.5-m Pin pile                1 WTG  4 WTG pin
                                                                                         Monopile     +4 OSP
                                                                                          + 4 OSP  pin piles
                                                                                        pin piles
--------------------------------------------------------------------------------------------------------------------------------------------------------
Method                                                          Impact only                Impact       Vibe     Impact       Vibe         Impact
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale Visual Clearance/
 Shutdown Zone....................................              Sighting at any distance from PSOs on pile-driving or dedicated PSO vessels.
                                                   -----------------------------------------------------------------------------------------------------
North Atlantic right whale PAM \1\ Clearance/
 Shutdown Zone \1\................................                                  10,000 m (pin), 15,000 m (monopile).
                                                   -----------------------------------------------------------------------------------------------------
Other baleen whales Clearance/Shutdown Zone \1\...     3,500 (3,700)     2,000 (2,300)      3,500        200      1,900    \2\ NAS      3,500      2,600
Sperm whales & delphinids Clearance/Shutdown Zone                NAS               NAS        NAS        NAS        NAS        NAS        NAS        NAS
 \1\..............................................
Harbor porpoise Clearance/Shutdown Zone \1\.......               NAS               NAS        NAS        NAS        NAS        NAS        NAS        NAS
Seals Clearance/Shutdown Zone \1\.................         200 (400)               NAS        200        NAS        NAS        NAS        300        200
                                                   -----------------------------------------------------------------------------------------------------
Minimum Visibility Zone \3\.......................    Within NARW EMA Enhanced: 4,800 m (pin) 7,400 m (mono); Outside NARW EMA: equal to `other baleen
                                                                                whales' impact pile driving clearance zones.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ The PAM system used during clearance and shutdown must be designed to detect marine mammal vocalizations, maximize baleen whale detections, and must
  be capable of detecting North Atlantic right whales at 10 km (6.2 mi) and 15 km (9.3 mi) for pin piles and monopile installations, respectively. NMFS
  recognizes that detectability of each species' vocalizations will vary based on vocalization characteristics (e.g., frequency content, source level),
  acoustic propagation conditions, and competing noise sources), such that other marine mammal species (e.g., harbor porpoise) may not be detected at 10
  km (6.2 mi) or 15 km (9.3 mi).
\2\ NAS = noise attenuation system (e.g., double bubble curtain (DBBC)). This zone size designation indicates that the clearance and shutdown zones,
  based on modeled distances to the Level A harassment thresholds, would not extend beyond the DBBC deployment radius around the pile.
\3\ PSOs must be able to visually monitor minimum visibility zones. To provide enhanced protection of North Atlantic right whales during foundation
  installations in the NARW EMA, SouthCoast proposed monitoring of minimum visibility zones equal to the Level B harassment zones when installing pin
  piles (4.8 km (3.0 mi)) and monopiles (7.4 km (4.6 mi)). Outside the NARW EMA, the minimum visibility zone would be equal to SouthCoast's clearance/
  shutdown zones for `other baleen whales.'

    SouthCoast proposed the following clearance zone sizes for UXO/MEC 
detonation, which are dependent on the size (i.e., charge weight) of a 
UXO/MEC. SouthCoast has indicated that they will be able to determine 
the UXO/MEC charge weight prior to detonation. If the charge weight is 
determined to be unknown or uncertain, SouthCoast would implement the 
largest clearance zone (E12, 454 kg (1,001 lbs)) prior to detonation.

[[Page 53789]]



 Table 55--Level B Harassment and Clearance Zones (in Meters (m)) During UXO/MEC Detonations in the Export Cable Corridor (ECC) and Lease Area (LA), by
                                                  Charge Weight and Assuming 10 dB of Sound Attenuation
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                      Low-frequency         Mid-frequency        High-frequency       Phocid pinnipeds
                                                                        cetaceans             cetaceans             cetaceans      ---------------------
                     UXO/MEC charge weights                      ------------------------------------------------------------------
                                                                     ECC         LA        ECC         LA        ECC         LA        ECC         LA
--------------------------------------------------------------------------------------------------------------------------------------------------------
PAM Clearance Zone \1\..........................................                                           15 km
                                                                 ---------------------------------------------------------------------------------------
E4 (2.3 kg):
    Level B harassment (m)......................................      2,800      2,900        500        500      6,200      6,200      1,300      1,500
    Clearance Zone (m)..........................................        800        400        100         50      2,500      2,200        300        100
E6 (9.1 kg):
    Level B harassment (m)......................................      4,500      4,700        800        800      7,900      8,000      2,200      2,400
    Clearance Zone (m)..........................................      1,500        800        200         50      3,500      3,200        500        200
E8 (45.5 kg):
    Level B harassment (m)......................................      7,300      7,500      1,300      1,300     10,100     10,300      3,900      3,900
    Clearance Zone (m)..........................................      2,900      1,800        300        100      4,900      4,900      1,000        600
E10 (227 kg):
    Level B harassment (m)......................................     10,300     10,500      2,100      2,200     12,600     12,900      6,000      6,000
    Clearance Zone (m)..........................................      4,200      3,400        500        300      6,600      7,200      1,900      1,200
E12 (454 kg):
    Level B harassment (m)......................................     11,800     11,900      2,500      2,600     13,700     14,100      7,100      7,000
    Clearance Zone (m)..........................................      4,900      4,300        600        400      7,400      8,700      2,600      1,600
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ The PAM system used during clearance must be designed to detect marine mammal vocalizations, maximize baleen whale detections, and must be capable
  of detecting North Atlantic right whales at 15 km (9.3 mi). NMFS recognizes that detectability of each species' vocalizations will vary based on
  vocalization characteristics (e.g., frequency content, source level), acoustic propagation conditions, and competing noise sources), such that other
  marine mammal species (e.g., harbor porpoise) may not be detected at 10 km (6.2 mi) or 15 km (9.3 mi).

    For an HRG survey clearance process that had begun in conditions 
with good visibility, including via the use of night vision equipment 
(i.e., IR/thermal camera), and during which the Lead PSO has determined 
that the clearance zones (table 56) are clear of marine mammals, survey 
operations would be allowed to commence (i.e., no delay is required) 
despite periods of inclement weather and/or loss of daylight.

              Table 56--Level B Harassment Threshold Ranges and Mitigation Zones During HRG Surveys
----------------------------------------------------------------------------------------------------------------
                                             Level B
                                         harassment zone        Level B        Clearance zone     Shutdown zone
                Species                   boomer/sparker    harassment zone          (m)               (m)
                                               (m)             CHIRPs (m)
----------------------------------------------------------------------------------------------------------------
North Atlantic right whale............                141                 48               500               500
Other baleen whales \1\...............                                                     100               100
Mid-frequency cetaceans \2\...........                141                 48               100           \1\ 100
High-frequency cetaceans..............                141                 48               100               100
Phocid Pinnipeds......................                141                 48               100               100
----------------------------------------------------------------------------------------------------------------
\1\ Baleen whales other the North Atlantic right whale.
\2\ An exception is noted for bow-riding delphinids of the following genera: Delphinus, Stenella,
  Lagenorhynchus, and Tursiops.

    For any other in-water construction heavy machinery activities 
(e.g., trenching, cable laying, etc.), if a marine mammal is on a path 
towards or comes within 10 m (32.8 ft) of equipment, SouthCoast Wind 
would be required to delay or cease operations until the marine mammal 
has moved more than 10 m (32.8 ft) on a path away from the activity to 
avoid direct interaction with equipment.

Soft-Start and Ramp-Up

    The use of a soft-start for impact pile driving or ramp-up for HRG 
surveys procedures are employed to provide additional protection to 
marine mammals by warning them or providing them with a chance to leave 
the area prior to the impact hammer or HRG equipment operating at full 
capacity. Soft-start typically involves initiating hammer operation at 
a reduced energy level, relative to the full operating capacity, 
followed by a waiting period. It is difficult to specify a reduction in 
energy for any given hammer because of variation across drivers and 
installation conditions. Typically, NMFS requires a soft-start 
procedure of the applicant performing four to six strikes per minute at 
10 to 20 percent of the maximum hammer energy, for a minimum of 20 
minutes. To allow maximum flexibility given Project-specific conditions 
and any number of safety issues, particularly if pile driving stops 
before target pile penetration depth is reached, which may result in 
pile refusal, general soft-start requirements are incorporated into the 
proposed regulatory text at proposed section 217.334(c)(6) but specific 
soft-start protocols considering final construction design details, 
including site-specific soil properties and other considerations, would 
be identified in their Pile Driving Monitoring Plan, which SouthCoast 
would submit to NMFS for approval prior to begin foundation 
installation.
    HRG survey operators are required to ramp-up sources when the 
acoustic sources are used unless the equipment operates on a binary on/
off switch. The ramp-up would involve starting from the smallest 
setting to the operating level over a period of approximately 30 
minutes.
    Soft-start and ramp-up would be required at the beginning of each 
day's activity and at any time following a cessation of activity of 30 
minutes or longer. Prior to soft-start or ramp-up beginning, the 
operator must receive confirmation from the PSO that the

[[Page 53790]]

clearance zone is clear of any marine mammals.

Fishery Monitoring Surveys

    While the likelihood of SouthCoast Wind's fishery monitoring 
surveys impacting marine mammals is minimal, NMFS is proposing to 
require SouthCoast Wind to adhere to gear and vessel mitigation 
measures to reduce the risk of gear interaction to de minimis levels. 
In addition, all crew undertaking the fishery monitoring survey 
activities would be required to receive protected species 
identification training prior to activities occurring and attend the 
aforementioned onboarding training. The specific requirements that NMFS 
is proposing for the fishery monitoring surveys can be found in the 
proposed regulatory text in proposed section 217.334(f).
    Based on our evaluation of the mitigation measures, as well as 
other measures considered by NMFS, NMFS has preliminarily determined 
that these measures will provide the means of affecting 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.

Proposed Monitoring and Reporting

    In order to promulgate a rulemaking for an activity, section 
101(a)(5)(A) of the MMPA states that NMFS must set forth requirements 
pertaining to the monitoring and reporting of such taking. The MMPA 
implementing regulations at 50 CFR 216.104 (a)(13) indicate that 
requests for authorizations must include the suggested means of 
accomplishing the necessary monitoring and reporting that will result 
in increased knowledge of the species and of the level of taking or 
impacts on populations of marine mammals that are expected to be 
present in the project area. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (i.e., individual or cumulative, acute 
or chronic), through better understanding of: (1) action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the action; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (i.e., behavioral or 
physiological) to acoustic stressors (i.e., acute, chronic, or 
cumulative), other stressors, or cumulative impacts from multiple 
stressors;
     How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and/or
     Mitigation and monitoring effectiveness.
    Separately, monitoring is also regularly used to support mitigation 
implementation (i.e., mitigation monitoring) and monitoring plans 
typically include measures that both support mitigation implementation 
and increase our understanding of the impacts of the activity on marine 
mammals.

North Atlantic Right Whale Awareness Monitoring

    SouthCoast Wind must use available sources of information on North 
Atlantic right whale presence, including, but not limited to, daily 
monitoring of the Right Whale Sightings Advisory System, Whale Alert, 
and monitoring of U.S. Coast Guard very high frequency (VHF) Channel 16 
throughout each day to receive notifications of any sightings and 
information associated with any regulatory management actions (e.g., 
establishment of a zone identifying the need to reduce vessel speeds). 
Maintaining frequent daily awareness of North Atlantic right whale 
presence in the area through SouthCoast's ongoing visual and passive 
acoustic monitoring efforts and opportunistic data sources (outside of 
SouthCoast Wind's efforts) and subsequent coordination for 
disseminating that information across Project personnel affords 
increased protection of North Atlantic right whales by alerting project 
personnel and the marine mammal monitoring team to a higher likelihood 
of encountering a North Atlantic right whale, potentially increasing 
the efficacy of mitigation and vessel strike avoidance efforts. 
Finally, at least one PAM operator must review available passive 
acoustic data collected in the project area within at least the 24 
hours, the duration recommended by Davis et al. (2023), prior to 
foundation installation or any UXO/MEC detonations to identify 
detections of North Atlantic right whales and convey that information 
to project personnel (e.g., vessel operators and crew, PSOs).
    In addition to utilizing available sources of information on marine 
mammal presence as described above, SouthCoast would be required to 
employ and utilize a marine mammal visual monitoring team to monitor 
throughout (i.e., before, during, and after) all specified activities 
(i.e., foundation installation, UXO/MEC detonation, and HRG surveys) 
consisting of NMFS-approved vessel-based PSOs and trained lookouts on 
all vessels, and PAM operator(s) to monitor throughout foundation 
installation and UXO/MEC detonation. Visual observations and acoustic 
detections would be used to support the activity-specific mitigation 
measures (e.g., clearance zones). To increase understanding of the 
impacts of the activity on marine mammals, PSOs must record all 
incidents of marine mammal occurrence at any distance from the piling 
locations, near the HRG acoustic sources, and during UXO/MEC 
detonations. PSOs would document all behaviors and behavioral changes, 
in concert with distance from an acoustic source. Further, SFV during 
foundation installation and UXO/MEC detonation is required to ensure 
compliance and that the potential impacts are within the bounds of that 
analyzed. The required monitoring, including PSO and PAM Operator 
qualifications, is described below, beginning with PSO measures that 
are applicable to all the aforementioned activities and PAM (for 
specific activities).

Protected Species Observer and PAM Operator Requirements

    SouthCoast Wind would be required to employ NMFS-approved PSOs and 
PAM operators for certain activities. PSOs are trained professionals 
who are tasked with visually monitoring for marine mammals during pile 
driving, UXO/MEC detonations, and HRG surveys. The primary purpose of a 
PSO is to carry out the monitoring, collect data, and, when 
appropriate, call for the implementation of mitigation measures. In 
addition to visual observations, NMFS would require SouthCoast Wind to 
conduct real-time acoustic monitoring by PAM operators during 
foundation pile driving, UXO/MEC detonation, and vessel transit over 10 
knots (18.5 km/hr).
    The inclusion of PAM, which would be conducted by NMFS-approved PAM

[[Page 53791]]

operators utilizing standardized measurement, processing, reporting, 
and metadata methods and metrics for offshore wind, combined with 
visual data collection, is a valuable way to provide the most accurate 
record of species presence as possible and, together, these two 
monitoring methods are well understood to provide best results when 
combined together (e.g., Barlow and Taylor, 2005; Clark et al., 2010; 
Gerrodette et al., 2011; Van Parijs et al., 2021). Acoustic monitoring 
(in addition to visual monitoring) increases the likelihood of 
detecting marine mammals, if they are vocalizing, within the shutdown 
and clearance zones of project activities, which when applied in 
combination of required shutdowns helps to further reduce the risk of 
marine mammals being exposed to sound levels that could otherwise 
result in acoustic injury or more intense behavioral harassment. The 
exact configuration and number of PAM systems depends on the size of 
the zone(s) being monitored, the amount of noise expected in the area, 
and the characteristics of the signals being monitored.
    The exact configuration and number of PAM systems depends on the 
size of the zone(s) being monitored, the amount of noise expected in 
the area, and the characteristics of the signals being monitored. More 
closely-spaced hydrophones would allow for more directionality and 
range to the vocalizing marine mammals. Larger baleen cetacean species 
(i.e., mysticetes), which produce loud and lower-frequency 
vocalizations, may be able to be heard with fewer hydrophones spaced at 
greater distances. However, detection of smaller cetaceans (e.g., mid-
frequency delphinids; odontocetes) may necessitate more hydrophones and 
to be spaced closer together given the shorter range of the shorter, 
mid-frequency acoustic signals (e.g., whistles and echolocation 
clicks). As there are no ``perfect fit'' single-optimal-array 
configurations, these set-ups would need to be considered on a case-by-
case basis.
    NMFS does not formally administer any PSO or PAM operator training 
programs or endorse specific providers but would approve PSOs and PAM 
operators that have successfully completed courses that meet the 
curriculum and training requirements referenced below and/or 
demonstrate experience. PSOs would be allowed to act as PAM operators 
or PSOs (but not simultaneously) as long as they demonstrate that their 
training and experience are sufficient to perform each task.
    NMFS would provide PSO and PAM operator approval, if the candidate 
is qualified, to ensure that PSOs and PAM operators have the necessary 
training and/or experience to carry out their duties competently. NMFS 
may approve PSOs and PAM operators as conditional or unconditional. A 
conditionally-approved PSO may be one who has completed training in the 
last 5 years but has not yet attained the requisite field experience. 
An unconditionally approved PSO is one who has completed training 
within the last 5 years (or completed training earlier but has 
demonstrated recent experience acting as a PSO) and attained the 
necessary experience (i.e., demonstrate experience with monitoring for 
marine mammals at clearance and shutdown zone sizes similar to those 
produced during the respective activity). The specific requirements for 
conditional and unconditional approval can be found in the proposed 
regulatory text in proposed section 217.335(a)(7). PSOs and PAM 
operators for pile driving and UXO/MEC detonation must be 
unconditionally approved. PSOs for HRG surveys may be conditionally or 
unconditionally approved; however, conditionally-approved PSOs must be 
paired with an unconditional-approved PSO to ensure that the quality of 
marine mammal observations and data recording is kept consistent.
    At least one PSO and PAM operator per platform must be designated 
as a Lead. To qualify as a Lead PSO or PAM operator, the person must be 
unconditionally approved and demonstrate that they have a minimum of 90 
days of at-sea experience monitoring marine mammals in the specific 
role, with the conclusion of the most recent relevant experience not 
more than 18 months previous to deployment. The person must also have 
experience specifically monitoring baleen whale species;
    SouthCoast Wind must submit a list of previously approved PSOs and 
PAM operators to NMFS Office of Protected Resources for review and 
confirmation of their approval for specific roles at least 30 days 
prior to commencement of the activities requiring PSOs and PAM 
operators or 15 days prior to when new, previously approved PSOs and 
PAM operators are required after activities have commenced. For 
prospective PSOs and PAM operators not previously approved or for PSOs 
and PAM operators whose approval is not current, SouthCoast Wind must 
submit resumes for approval to NMFS at least 60 days prior to PSO and 
PAM operator use. Resumes must include information related to roles for 
which approval is being sought, relevant education, experience, and 
training, including dates, duration, location, and description of prior 
PSO or PAM operator experience. Resumes must be accompanied by relevant 
documentation of successful completion of necessary training.
    The number of PSOs and PAM operators that would be required to 
actively observe for the presence of marine mammals are specific to 
each activity, as are the types of equipment required (e.g., big eyes 
on the pile driving vessel; acoustic buoys) to increase marine mammal 
detection capabilities. A minimum of three on-duty PSOs per platform 
(e.g., pile driving vessel, dedicated PSO vessel) would conduct 
monitoring before, during, and after foundation installations and UXO/
MEC detonations. A minimum number of PAM operators would be required to 
actively monitor for marine mammal acoustic detections for these 
activities; this number would be based on the PAM systems and specified 
in the PAM Plan SouthCoast would submit for NMFS approval prior to the 
start of in-water activities. At least one PSO must be on-duty during 
HRG surveys conducted during daylight hours; and at least two PSOs must 
be on-duty during HRG surveys conducted during nighttime. NMFS would 
not require PAM or PAM operators during HRG surveys.
    The number of platforms from which the required number of PSOs 
would conduct monitoring depends on the activity and timeframe. Within 
the NARW EMA from June 1-August 15 and outside the NARW EMA June 1-
November 30, SouthCoast would conduct monitoring before, during, and 
after foundation installation from three dedicated PSO monitoring 
vessels, in addition to the pile driving platform. Within the NARW EMA 
from August 16-October 15 and outside the NARW EMA May 16-May 31 and 
December 1-31 (if NMFS approved SouthCoast's request for allowance to 
install foundations in December), PSOs would monitor from four 
dedicated PSO vessels and the pile driving vessel (i.e., five platforms 
total). The number of monitoring platforms required for UXO/MEC 
detonations depends on the charge weight. For detonation of lower 
charge weight (E4-E8) UXO/MECs, SouthCoast would conduct monitoring 
from the main activity platform and a dedicated PSO monitoring 
platform. If, after attempting all methods of UXO/MEC disposal, 
SouthCoast must detonate a

[[Page 53792]]

heavier charge weight UXO/MEC (i.e., E10 or E12) that is predicted to 
result in a larger ensonified zone (i.e., >5 km), additional monitoring 
platforms (i.e., vessel, plane) would be required. During HRG surveys, 
PSOs would conduct monitoring from the survey vessels. In addition to 
monitoring duties, PSOs and PAM operators are responsible for data 
collection. The data collected by PSO and PAM operators and subsequent 
analysis provide the necessary information to inform an estimate of the 
number of take that occurred during the project, better understand the 
impacts of the project on marine mammals, address the effectiveness of 
monitoring and mitigation measures, and to adaptively manage activities 
and mitigation in the future. Data reported includes information on 
marine mammal sightings, activity occurring at time of sighting, 
monitoring conditions, and if mitigative actions were taken. Specific 
data collection requirements are contained within the regulations at 
the end of this rulemaking.
    SouthCoast Wind would be required to submit Pile Driving and UXO/
MEC Detonation Marine Mammal Monitoring Plans and a PAM Plan to NMFS 
180 days in advance of foundation installation and UXO/MEC detonation. 
The Plans must include details regarding PSO and PAM monitoring 
protocols and equipment proposed for use, as described in the draft LOA 
available at https://www.fisheries.noaa.gov/action/incidental-take-authorization-southcoast-wind-llc-construction-southcoast-wind-offshore-wind. More specifically, the PAM Plan must, among other 
things, include a description of all proposed PAM equipment, address 
how the proposed passive acoustic monitoring must follow standardized 
measurement, processing methods, reporting metrics, and metadata 
standards for offshore wind as described in NOAA and BOEM Minimum 
Recommendations for Use of Passive Acoustic Listening Systems in 
Offshore Wind Energy Development Monitoring and Mitigation Programs 
(Van Parijs et al., 2021). NMFS must approve the Plans prior to 
foundation installation activities or UXO/MEC detonation commencing.

Sound Field Verification (SFV)

    SouthCoast would be required to conduct SFV measurements during all 
foundation installations and all UXO/MEC detonations. At minimum, the 
first three monopile foundations and four pin piles must be monitored 
with Thorough SFV (T-SFV), which requires, at minimum, measurements at 
four locations along one transect from the pile with each recorder 
equipped with two hydrophones as well as an additional recorder at a 90 
degrees from the transect (total of 10 hydrophones). For example, 
SouthCoast would deploy acoustic recorders at positions 750 m (2,460.6 
ft), 1500 m (4,921.3 ft)), 3000 m (9,842.5 ft), and 10,000 m (32,808.4 
ft) in a single linear array due south and another acoustic recorder 
due east of the foundation installation location. SFV protocols for 
impact pile driving, can be found in ISO 18406 Underwater acoustics--
Measurement of radiated underwater sound from percussive pile driving 
(2017). T-SFV measurements must continue until at least three 
consecutive piles demonstrate distances to thresholds are at or below 
those modeled assuming 10 dB of attenuation. Subsequent T-SFV 
measurements are also required should larger piles be installed or 
additional piles be driven that are anticipated to produce longer 
distances to harassment isopleths than those previously measured (e.g., 
higher hammer energy, greater number of strikes, etc.). The required 
reporting metrics associated with T-SFV can be found in the draft LOA. 
The requirements are extensive to ensure monitoring is conducted 
appropriately and the reporting (i.e., communicating monitoring results 
to NMFS) is frequent to ensure SouthCoast is making any necessary 
adjustments quickly (e.g., ensure bubble curtain hose maintenance, 
check bubble curtain air pressure supply, add additional sound 
attenuation) to ensure impacts to marine mammals are not above those 
considered in this analysis. SouthCoast would be required to conduct 
abbreviated SFV (A-SFV) on all piles for which T-SFV is not conducted; 
the reporting requirements and frequency of reporting can be found in 
the proposed regulatory text at proposed section 217.334(c)(20). 
SouthCoastWind must also conduct SFV during operations to better 
understand the sound fields and potential impacts on marine mammals 
associated with turbine operations.

Reporting

    Prior to any construction activities occurring, SouthCoast would be 
required to provide a report to NMFS Office of Protected Resources that 
demonstrates that all SouthCoast personnel, including the vessel crews, 
vessel captains, PSOs, and PAM operators have completed all required 
trainings.
    NMFS would require standardized and frequent reporting from 
SouthCoast Wind during the life of the regulations and LOA. All data 
collected relating to the Project would be recorded using industry-
standard software (e.g., Mysticetus or a similar software) installed on 
field laptops and/or tablets. SouthCoast Wind is required to submit 
weekly, monthly, annual, and situational, and final reports. The 
specifics of what we require to be reported can be found in the 
proposed regulatory text at proposed section 217.335(c).
    Weekly Report--During foundation installation activities, 
SouthCoast would be required to compile and submit weekly marine mammal 
monitoring reports for foundation installation pile driving to NMFS 
Office of Protected Resources that document the daily start and stop of 
all pile-driving activities, the start and stop of associated 
observation periods by PSOs, details on the deployment of PSOs, a 
record of all detections of marine mammals (acoustic and visual), any 
mitigation actions (or if mitigation actions could not be taken, 
provide reasons why), and details on the noise abatement system(s) 
(e.g., system type, distance deployed from the pile, bubble rate, 
etc.), and A-SFV results. Weekly reports will be due on Wednesday for 
the previous week (Sunday to Saturday). The weekly reports are also 
required to identify which turbines become operational and when (a map 
must be provided). Once all foundation pile installation is complete, 
weekly reports would no longer be required.
    Monthly Report--SouthCoast would be required to compile and submit 
monthly reports to NMFS Office of Protected Resources that include a 
summary of all information in the weekly reports, including project 
activities carried out in the previous month, vessel transits (number, 
type of vessel, and route), number of piles installed, all detections 
of marine mammals, and any mitigative actions taken. Monthly reports 
would be due on the 15th of the month for the previous month. The 
monthly report would also identify which turbines become operational 
and when, and a map must be provided. Once all foundation pile 
installation is complete, monthly reports would no longer be required.
    Annual Reporting--SouthCoast is required to submit an annual marine 
mammal monitoring (including visual and acoustic observations of marine 
mammals) report to NMFS Office of Protected Resources by March 31st, 
annually, describing in detail all of the information required in the 
monitoring section above for the previous calendar year. A final annual 
report must be prepared and submitted within 30 calendar days following 
receipt of any NMFS comments on the draft report.

[[Page 53793]]

    Final Reporting--SouthCoast must submit its draft 5-year report(s) 
to NMFS Office of Protected Resources. The report must contain, but is 
not limited to, a description of activities conducted (including GIS 
files where relevant), and all visual and acoustic monitoring, 
including all SFV and monitoring effectiveness, conducted under the LOA 
within 90 calendar days of the completion of activities occurring under 
the LOA. A final 5-year report must be prepared and submitted within 60 
calendar days following receipt of any NMFS comments on the draft 
report.
    Situational Reporting--Specific situations encountered during the 
development of the Project requires immediate reporting. For instance, 
if a North Atlantic right whale is observed at any time by PSOs or 
project personnel, the sighting must be immediately (if not feasible, 
as soon as possible and no longer than 24 hours after the sighting) 
reported to NMFS. If a North Atlantic right whale is acoustically 
detected at any time via a project-related PAM system, the detection 
must be reported as soon as possible and no longer than 24 hours after 
the detection to NMFS via the 24-hour North Atlantic right whale 
Detection Template (https://www.fisheries.noaa.gov/resource/document/passive-acoustic-reporting-system-templates). Calling the hotline is 
not necessary when reporting PAM detections via the template.
    If a sighting of a stranded, entangled, injured, or dead marine 
mammal occurs, the sighting would be reported to NMFS Office of 
Protected Resources, the NMFS Greater Atlantic Stranding Coordinator 
for the New England/Mid-Atlantic area (866-755-6622), and the U.S. 
Coast Guard within 24 hours. If the injury or death was caused by a 
project activity, SouthCoast Wind must immediately cease all activities 
until NMFS Office of Protected Resources is able to review the 
circumstances of the incident and determine what, if any, additional 
measures are appropriate to ensure compliance with the terms of the 
LOA. NMFS Office of Protected Resources may impose additional measures 
to minimize the likelihood of further prohibited take and ensure MMPA 
compliance. SouthCoast may not resume their activities until notified 
by NMFS Office of Protected Resources.
    In the event of a vessel strike of a marine mammal by any vessel 
associated with the Project, SouthCoast Wind must immediately report 
the strike incident. If the strike occurs in the Greater Atlantic 
Region (Maine to Virginia), SouthCoast must call the NMFS Greater 
Atlantic Stranding Hotline. Separately, SouthCoast must also and 
immediately report the incident to NMFS Office of Protected Resources 
and GARFO. SouthCoast must immediately cease all on-water activities 
until NMFS Office of Protected Resources is able to review the 
circumstances of the incident and determine what, if any, additional 
measures are appropriate to ensure compliance with the terms of the 
LOA. NMFS Office of Protected Resources may impose additional measures 
to minimize the likelihood of further prohibited take and ensure MMPA 
compliance. SouthCoast Wind may not resume their activities until 
notified by NMFS.
    In the event of any lost gear associated with the fishery surveys, 
SouthCoast must report to the GARFO as soon as possible or within 24 
hours of the documented time of missing or lost gear. This report must 
include information on any markings on the gear and any efforts 
undertaken or planned to recover the gear.
    The specifics of what NMFS Office of Protected Resources proposes 
to require to be reported are included in the draft LOA.
    Sound Field Verification--SouthCoast is required to submit interim 
T-SFV reports after each foundation installation and UXO/MEC detonation 
as soon as possible but no later than 48 hours after monitoring of each 
activity is complete. Reports for A-SFV must be included in the weekly 
monitoring reports. The final SFV report (including both A-SFV and T-
SFV results) for all foundation installations and UXO/MEC detonations 
would be required within 90 days following completion of sound field 
verification monitoring.

Adaptive Management

    The regulations governing the take of marine mammals incidental to 
SouthCoast's construction activities contain an adaptive management 
component. Our understanding of the effects of offshore wind 
construction activities (e.g., acoustic and explosive stressors) on 
marine mammals continues to evolve, which makes the inclusion of an 
adaptive management component both valuable and necessary within the 
context of 5-year regulations.
    The monitoring and reporting requirements in this proposed rule 
will provide NMFS with information that helps us to better understand 
the impacts of the project's activities on marine mammals and informs 
our consideration of whether any changes to mitigation and monitoring 
are appropriate. The use of adaptive management allows NMFS to consider 
new information and modify mitigation, monitoring, or reporting 
requirements, as appropriate, with input from SouthCoast regarding 
practicability, if such modifications will have a reasonable likelihood 
of more effectively accomplishing the goals of the measures.
    The following are some of the possible sources of new information 
to be considered through the adaptive management process: (1) results 
from monitoring reports, including the weekly, monthly, situational, 
and annual reports required; (2) results from research on marine 
mammals, noise impacts, or other related topics; and (3) any 
information that reveals that marine mammals may have been taken in a 
manner, extent, or number not authorized by these regulations or 
subsequent LOA. Adaptive management decisions may be made at any time, 
as new information warrants it. NMFS may consult with SouthCoast Wind 
regarding the practicability of the modifications.

Preliminary Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' by mortality, serious injury, Level A harassment and Level B 
harassment, we consider other factors, such as the likely nature of any 
behavioral responses (e.g., intensity, duration), the context of any 
such responses (e.g., critical reproductive time or location, 
migration) as well as effects on habitat and the likely effectiveness 
of mitigation. We also assess the number, intensity, and context of 
estimated takes by evaluating this information relative to population 
status. Consistent with the 1989 preamble for NMFS' implementing 
regulations (54 FR 40338, September 29, 1989), the impacts from other 
past and ongoing anthropogenic activities are incorporated into this 
analysis via their impacts on the environmental baseline (e.g., as 
reflected in the regulatory status of the species, population size and 
growth rate where known, ongoing

[[Page 53794]]

sources of human-caused mortality, or ambient noise levels).
    In the Estimated Take section, we estimated the maximum number of 
takes, by Level A harassment and Level B harassment, of marine mammal 
species and stocks that could occur incidental to SouthCoast's 
specified activities. The impact on the affected species and stock that 
any given take may have is dependent on many case-specific factors that 
need to be considered in the negligible impact analysis (e.g., the 
context of behavioral exposures such as duration or intensity of a 
disturbance, the health of impacted animals, the status of a species 
that incurs fitness-level impacts to individuals, etc.). In this 
proposed rule, we evaluate the likely impacts of the enumerated 
harassment takes that are proposed for authorization, in consideration 
of the context in which the predicted takes would occur. We also 
collectively evaluate this information as well as other more taxa-
specific information and mitigation measure effectiveness in group-
specific discussions that support our preliminary negligible impact 
determinations for each stock. No serious injury or mortality is 
expected or proposed for authorization for any species or stock.
    The Description of the Specified Activities section describes 
SouthCoast's specified activities that may result in the take of marine 
mammals and an estimated schedule for conducting those activities. 
SouthCoast has provided a realistic construction schedule, although we 
recognize schedules may shift for a variety of reasons (e.g., weather 
or supply delays). For each species, the maximum number of annual takes 
proposed for authorization is based on the pile driving scenario for 
each year (table X) that resulted in the highest number of Level B 
harassment takes for a given species. The 5-year total number of takes 
proposed for authorization is based on installation of Project 1 
Scenario 1 in a single year and Project 2 Scenario 2 in a single year. 
The total number of authorized takes would not exceed the maximum 
annual totals in any given year or the 5-year total take specified in 
tables 53 and 52, respectively.
    We base our analysis and preliminary negligible impact 
determination on the maximum number of takes that are proposed for 
authorization in any given year and the total takes proposed for 
authorization across the 5-year effective period of these regulations, 
if issued, as well as extensive qualitative consideration of other 
contextual factors that influence the severity and nature of impacts on 
affected individuals and the number and context of the individuals 
affected. As stated before, the number of takes, both maximum annual 
and 5-year totals, alone are only a part of the analysis.
    To avoid repetition, we provide some general analysis in this 
Negligible Impact Analysis and Determination section that applies to 
all the species listed in table 5, given that some of the anticipated 
effects of SouthCoast Wind's specified activities on marine mammals are 
expected to be relatively similar in nature. Then, we subdivide into 
more detailed discussions for mysticetes, odontocetes, and pinnipeds, 
which have broad life history traits that support an overarching 
discussion of some factors considered within the analysis for those 
groups (e.g., habitat-use patterns, high-level differences in feeding 
strategies).
    Last, we provide a preliminary negligible impact determination for 
each species or stock, providing information relevant to our analysis, 
where appropriate. Organizing our analysis by grouping species or 
stocks that share common traits or that would respond similarly to 
effects of SouthCoast's activities and then providing species- or 
stock-specific information allows us to avoid duplication while 
ensuring that we have analyzed the effects of the specified activities 
on each affected species or stock. It is important to note that for all 
species or stocks, the majority of the impacts are associated with WTG 
and OSP foundation installation, which would occur over 2 years per 
SouthCoast's schedule (tables 19-23). The maximum annual take for each 
species or stock would occur during construction of Project 2. The 
number of takes proposed for authorization by NMFS in other years would 
be notably less.
    As described previously, no serious injury or mortality is 
anticipated or proposed for authorization. Non-auditory injury (e.g., 
lung injury or gastrointestinal injury from UXO/MEC detonation) is also 
not anticipated due to the proposed mitigation measures and would not 
be authorized in any LOA issued under this rule. Any Level A harassment 
authorized would be in the form of auditory injury (i.e., PTS).

Behavioral Disturbance

    In general, NMFS anticipates that impacts on an individual that has 
been harassed are likely to be more intense when exposed to higher 
received levels and for a longer duration (though this is not a 
strictly linear relationship for behavioral effects across species, 
individuals, or circumstances) and less severe impacts result when 
exposed to lower received levels and for a brief duration. However, 
there is also growing evidence of the importance of contextual factors, 
such as distance from a source in predicting marine mammal behavioral 
response to sound--i.e., sounds of a similar level emanating from a 
more distant source have been shown to be less likely to evoke a 
response of equal magnitude (e.g., DeRuiter and Doukara, 2012; Falcone 
et al., 2017). As described in the Potential Effects to Marine Mammals 
and their Habitat section, the intensity and duration of any impact 
resulting from exposure to SouthCoast's activities is dependent upon a 
number of contextual factors including, but not limited to, sound 
source frequencies, whether the sound source is stationary or moving 
towards the animal, hearing ranges of marine mammals, behavioral state 
at time of exposure, status of individual exposed (e.g., reproductive 
status, age class, health) and an individual's experience with similar 
sound sources. Southall et al. (2021), Ellison et al. (2012), and Moore 
and Barlow (2013), among others, emphasize the importance of context 
(e.g., behavioral state of the animals, distance from the sound source) 
in evaluating behavioral responses of marine mammals to acoustic 
sources. Harassment of marine mammals may result in behavioral 
modifications (e.g., avoidance, temporary cessation of foraging or 
communicating, changes in respiration or group dynamics, masking) or 
may result in auditory impacts such as hearing loss. In addition, some 
of the lower level physiological stress responses (e.g., change in 
respiration, change in heart rate) discussed previously would likely 
co-occur with the behavioral modifications, although these 
physiological responses are more difficult to detect and fewer data 
exist relating these responses to specific received levels of sound. 
Level B harassment takes, then, may have a stress-related physiological 
component as well; however, we would not expect SouthCoast's activities 
to produce conditions of long-term and continuous exposure to noise 
leading to long-term physiological stress responses in marine mammals 
that could affect reproduction or survival.
    In the range of exposure intensities that might result in Level B 
harassment (which by nature of the way it is modeled/counted, occurs 
within one day), the less severe end might include exposure to 
comparatively lower levels of a sound, at a greater distance from the 
animal, for a few or several minutes. A

[[Page 53795]]

less severe exposure of this nature could result in a behavioral 
response such as avoiding a small area that an animal would otherwise 
have chosen to move through or feed in for some number of time, or 
breaking off one or a few feeding bouts. More severe effects could 
occur if an animal receives comparatively higher levels at very close 
distances, is exposed continuously to one source for a longer time, or 
is exposed intermittently throughout a day. Such exposure might result 
in an animal having a more severe avoidance response and leaving a 
larger area for an extended duration, potentially, for example, losing 
feeding opportunities for a day or more. Given the extensive mitigation 
and monitoring measures included in this rule, we anticipate severe 
behavioral effects to be minimized to the extent practicable.
    Many species perform vital functions, such as feeding, resting, 
traveling, and socializing on a diel cycle (24-hour cycle). Behavioral 
reactions to noise exposure, when taking place in a biologically 
important context, such as disruption of critical life functions, 
displacement, or avoidance of important habitat, are more likely to be 
significant if they last more than one day or recur on subsequent days 
(Southall et al., 2007) due to diel and lunar patterns in diving and 
foraging behaviors observed in many cetaceans (Baird et al., 2008; 
Barlow et al., 2020; Henderson et al., 2016, Schorr et al., 2014). It 
is important to note the water depth in the Lease Area and ECCs is 
shallow ranging from 0-41.5 in the ECCs and 37.1-63.4 in the Lease 
Area) and deep-diving species, such as sperm whales, are not expected 
to be engaging in deep foraging dives when exposed to noise above NMFS 
harassment thresholds during the specified activities. Therefore, we do 
not anticipate foraging behavior in deep water to be impacted by the 
specified activities.
    It is important to identify that the estimated number of takes for 
each stock does not necessarily equate to the number of individual 
marine mammals expected to be harassed (which may be lower, depending 
on the circumstances), but rather to the instances of take that may 
occur. These instances may represent either brief exposures of seconds 
for UXO/MEC detonations, seconds to minutes for HRG surveys, or, in 
some cases, longer durations of exposure within (but not exceeding) a 
day (e.g., pile driving). Some members of a species or stock may 
experience one exposure (i.e., be taken on one day) as they move 
through an area, while other individuals may experience recurring 
instances of take over multiple days throughout the year, in which case 
the number of individuals taken is smaller than the number of takes 
proposed for authorization for that species or stock. For species that 
are more likely to be migrating through the area and/or for which only 
a comparatively smaller number of takes are predicted (e.g., some of 
the mysticetes), it is more likely that each take represents a 
different individual. However, for non-migrating species or stocks with 
larger numbers of predicted take, we expect that the total anticipated 
takes represent exposures of a smaller number of individuals of which 
some would be taken across multiple days.
    For the SouthCoast Project, impact pile driving of foundation piles 
is most likely to result in a higher magnitude and severity of 
behavioral disturbance than other activities (i.e., vibratory pile 
driving, UXO/MEC detonations, and HRG surveys). Impact pile driving has 
higher source levels than vibratory pile driving and HRG surveys, and 
produces much lower frequencies than most HRG survey equipment, 
resulting in significantly greater sound propagation because lower 
frequencies typically propagate further than higher frequencies. While 
UXO/MEC detonations may have higher source levels than other 
activities, the number of UXO/MEC detonations is limited (10 over 5 
years) and each produces blast noise and pressure for an extremely 
short period (on the order of a fraction of a second near the source 
and seconds further from the source) as compared to multiple hours of 
pile driving or HRG surveys in a given day.
    While foundation installation impact pile driving is anticipated to 
result in the most takes due to high source levels, pile driving would 
not occur all day, every day. Table 2 describes the number of piles, by 
pile type and scenario, that may be driven each day. As described in 
the Description of Specified Activities section, impact driving could 
occur for up to 4 hours per monopile and 2 hours per pin pile. For 
those piles also including vibratory driving in Project 2, the duration 
of impact driving would be reduced. If vibratory pile driving is used 
to set the pile (Project 2 only), this would be limited to 20 minutes 
per monopile and 90 minutes per pin pile. No more than 2 monopiles or 4 
pin piles would be installed each day for the majority of 
installations. As described in the construction schedule scenarios 
(Table 2), on 3 or 4 days for each Project, two installation vessels 
would work concurrently to install WTG foundations and OSP foundations, 
further reducing the overall amount of time during which impact pile 
driving noise is transmitted into marine mammal habitat. Impacts would 
be minimized through implementation of mitigation measures, including 
use of a sound attenuation system, soft-starts, and the implementation 
of clearance and shutdown zones that either delay or suspend, 
respectively, pile driving when marine mammals are detected at 
specified distances. Further, given sufficient notice through the use 
of soft-start, marine mammals are expected to move away from a pile 
driving sound source prior to becoming exposed to very loud noise 
levels. The requirement to couple visual monitoring (using multiple 
PSOs) and PAM before and during all foundation installation and UXO/MEC 
detonations will increase the overall capability to detect marine 
mammals and effectively implement realtime mitigation measures, as 
compared to one method alone. Measures such as the requirement to apply 
noise attenuation systems and implementation of clearance zones also 
apply to UXO/MEC detonation(s), which also have the potential to elicit 
TTS and more severe behavioral reactions; hence, severity of TTS and 
behavioral responses, are expected to be lower than would be the case 
without noise mitigation.
    Occasional, milder behavioral reactions are unlikely to cause long-
term consequences for individual animals or populations. Even if some 
smaller subset of the takes are in the form of a longer (several hours 
or a day) and more severe response, if they are not expected to be 
repeated over numerous or sequential days, impacts to individual 
fitness are not anticipated. Nearly all studies and experts agree that 
infrequent exposures of a single day or less are unlikely to impact an 
individual's overall energy budget (Farmer et al., 2018; Harris et al., 
2017; King et al., 2015; National Academy of Science, 2017; New et al., 
2014; Southall et al., 2007; Villegas-Amtmann et al., 2015). Further, 
the effect of disturbance is strongly influenced by whether it overlaps 
with biologically important habitats when individuals are present--
avoiding biologically important habitats (which occur in both space and 
time) will provide opportunities to compensate for reduced or lost 
foraging (Keen et al., 2021). Importantly, the seasonal restrictions on 
pile driving and UXO/MEC detonation limit take to those times when 
species of particular concern are less likely to be present in 
biologically important habitats and, if present, less likely to be 
engaged in critical behaviors such as foraging. Temporary Threshold 
Shift (TTS)

[[Page 53796]]

Temporary Threshold Shift (TTS)

    TTS is one form of Level B harassment that marine mammals may incur 
through exposure to SouthCoast's activities and, as described earlier, 
the proposed takes by Level B harassment may represent takes in the 
form of behavioral disturbance, TTS, or both. As discussed in the 
Potential Effects to Marine Mammals and their Habitat section, in 
general, TTS can last from a few minutes to days, be of varying degree, 
and occur across different frequency bandwidths, all of which determine 
the severity of the impacts on the affected individual, which can range 
from minor to more severe. Impact and vibratory pile driving and UXO/
MEC detonations are broadband noise sources (i.e., produce sound over a 
wide range of frequencies) but most of the energy is concentrated below 
1-2 kHz, with a small amount of energy ranging up to 20 kHz. Low-
frequency cetaceans are most susceptible to noise-induced hearing loss 
at lower frequencies, given this is a frequency band in which they 
produce vocalizations to communicate with conspecifics, we would 
anticipate the potential for TTS incidental to pile driving and 
detonations to be greater in this hearing group (i.e., mysticetes) 
compared to others (e.g., mid-frequency). However, we would not expect 
the TTS to span the entire communication or hearing range of any 
species given that the frequencies produced by these activities do not 
span entire hearing ranges for any particular species. Additionally, 
though the frequency range of TTS that marine mammals might sustain 
would overlap with some of the frequency ranges of their vocalizations 
and other auditory cues for the time periods when they are in the 
vicinity of the sources, the frequency range of TTS from SouthCoast's 
pile driving and UXO/MEC detonation activities would not be expected to 
span the entire frequency range of one vocalization type, much less 
span all types of vocalizations or of all other critical auditory cues 
for any given species, much less for long continuous durations. The 
proposed mitigation measures further reduce the potential for TTS in 
mysticetes.
    Generally, both the degree of TTS and the duration of TTS would be 
greater if the marine mammal is exposed to a higher level of energy 
(which would occur when the peak dB level is higher or the duration is 
longer). The threshold for the onset of TTS was discussed previously 
(see Estimated Take). An animal would have to approach closer to the 
source or remain in the vicinity of the sound source appreciably longer 
to increase the received SEL, which would be unlikely considering the 
proposed mitigation and the nominal speed of the receiving animal 
relative to the stationary sources such as impact pile driving. The 
recovery time of TTS is also of importance when considering the 
potential impacts from TTS. In TTS laboratory studies (as discussed in 
Potential Effects of the Specified Activities on Marine Mammals and 
Their Habitat), some using exposures of almost an hour in duration or 
up to 217 SEL, almost all individuals recovered within 1 day (or less, 
often in minutes) and we note that while the pile driving activities 
last for hours a day, it is unlikely that most marine mammals would 
stay in close proximity to the source long enough to incur more severe 
TTS. UXO/MEC detonation also has the potential to result in TTS. 
However, given the duration of exposure is extremely short 
(milliseconds), the degree of TTS (i.e., the amount of dB shift) is 
expected to be small and TTS duration is expected to be short (minutes 
to hours). Overall, given the few instances in which any individual 
might incur TTS, the low degree of TTS and the short anticipated 
duration, and very low likelihood that any TTS would overlap the 
entirety of an individual's critical hearing range, it is unlikely that 
TTS (of the nature expected to result from SouthCoast's activities) 
would result in behavioral changes or other impacts that would impact 
any individual's (of any hearing sensitivity) reproduction or survival.

Permanent Threshold Shift (PTS)

    NMFS proposes to authorize a very small number of take by PTS to 
some marine mammals. The numbers of proposed annual takes by Level A 
harassment are relatively low for all marine mammal stocks and species 
(table 51). The only activities incidental to which we anticipate PTS 
may occur is from exposure to impact pile driving and UXO/MEC 
detonations, which produce sounds that are both impulsive and primarily 
concentrated in the lower frequency ranges (below 1 kHz) (David, 2006; 
Krumpel et al., 2021). PTS would consist of minor degradation of 
hearing capabilities occurring predominantly at frequencies one-half to 
one octave above the frequency of the energy produced by pile driving 
or instantaneous UXO/MEC detonation (i.e., the low-frequency region 
below 2 kHz) (Cody and Johnstone, 1981; McFadden, 1986; Finneran, 
2015), not severe hearing impairment. If hearing impairment occurs from 
either impact pile driving or UXO/MEC detonation, it is most likely 
that the affected animal would lose a few decibels in its hearing 
sensitivity, which in most cases is not likely to meaningfully affect 
its ability to forage and communicate with conspecifics.
    SouthCoast estimates 10 UXO/MECs may be detonated and the exposure 
analysis conservatively assumes that all of the UXO/MECs found would 
consist of the largest charge weight of UXO/MEC (E12; 454 kg (1,001 
lbs)). However, it is highly unlikely that all charges would be the 
maximum size; thus, the number of takes by Level A harassment that may 
occur incidental to the detonation of the UXO/MECs is likely less than 
what is estimated.
    There are no PTS data on cetaceans and only one instance of PTS 
being induced in older harbor seals (Reichmuth et al., 2019). However, 
available TTS data (of mid-frequency hearing specialists exposed to 
mid- or high-frequency sounds (Southall et al., 2007; NMFS, 2018; 
Southall et al., 2019)) suggest that most threshold shifts occur in the 
frequency range of the source up to one octave higher than the source. 
We would anticipate a similar result for PTS. Further, no more than a 
small degree of PTS is expected to be associated with any of the 
incurred Level A harassment given it is unlikely that animals would 
stay in the close vicinity of impact pile driving for a duration long 
enough to produce more than a small degree of PTS and given sufficient 
notice through use of soft-start prior to implementation of full hammer 
energy during impact pile driving, marine mammals are expected to move 
away from a sound source that is disturbing prior to it resulting in 
severe PTS. Given UXO/MEC detonations are instantaneous, the potential 
for PTS is not a function of duration. NMFS recognizes the distances to 
PTS thresholds may be large for certain species (e.g., over 8.6 km 
(28,215 ft) based on the largest charge weights; see tables 39-42); 
however, SouthCoast would utilize multiple vessels equipped with at 
minimum 3 PSOs each as well as PAM to observe and acoustically detect 
marine mammals. A marine mammal within the PTS zone would trigger a 
delay to detonation until the clearance zones are declared clear of 
marine mammals, thereby minimizing potential for PTS for all marine 
mammal species and ensuring that any PTS that does occur is of a 
relatively low degree.

Auditory Masking or Communication Impairment

    The ultimate potential impacts of masking on an individual are 
similar to those discussed for TTS (e.g., decreased ability to 
communicate, forage

[[Page 53797]]

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

Impacts on Habitat and Prey

    Pile driving associated with foundation installation or UXO/MEC 
detonation may result in impacts to prey, the extent to which based, in 
part, on the specific prey type. While fish and invertebrate mortality 
or injury may occur, it is anticipated that these types of impacts 
would be limited to a very small subset of available prey very close to 
the source, and that the implementation of mitigation measures (e.g., 
use of a noise attenuation system during pile driving and UXO/MEC 
detonation, soft-starts for pile driving) would limit the severity and 
extent of impacts (again, noting UXO/MEC detonation would be limited to 
10 events). Pile driving noise, both impact and vibratory, UXO.MEC 
detonations, and HRG surveys may cause mobile prey species, primarily 
fish, to temporarily leave the area of disturbance, resulting in 
temporary displacement from habitat near the pile driving or detonation 
site. For those HRG acoustic sources used by SouthCoast that operate at 
frequencies that are likely outside the hearing range of marine mammal 
prey species, no effects are anticipated.
    Any behavioral avoidance of the disturbed area by the subset of 
affected fish is expected to be localized (i.e., fish would not travel 
far from the site of disturbance) and temporary, thus piscivorous 
species (including marine mammals and some larger fish species), would 
still have access to significantly large areas of prey in foraging 
habitat in the nearby vicinity. Repeated exposure of individual fish to 
sound and energy from pile driving or underwater explosions is not 
likely, given fish movement patterns, especially schooling prey 
species. The duration of fish avoidance of an area after pile driving 
stops or a UXO/MEC is detonated is unknown, but it is anticipated that 
there would be a rapid return to normal recruitment, distribution and 
behavior following cessation of the disturbance. Long-term consequences 
for fish populations, including key prey species within the project 
area, would not be expected.
    Impacts to prey species with limited self-mobility (e.g., 
zooplankton) would also depend on proximity to the specified 
activities, without the potential for avoidance of the activity site on 
the same spatial scale as fishes and other mobile species. However, 
impacts to zooplankton, in the context of availability as marine mammal 
prey, from these activities are expected to be minimal, based on both 
experimental data and theoretical modeling of zooplankton population 
responses to airgun noise exposure (see Effects on Prey section). In 
general, the rapid reproductive rate of zooplankton, coupled with 
advection of zooplankton from sources outside of the Lease Area and 
ECCs would help support maintenance of the population in these areas, 
should pile driving or detonation activities result in changes in 
physiology impacting limiting reproduction (e.g., growth suppression) 
or mortality of zooplankton. Long-term impacts to zooplankton 
populations and their habitat from pile driving and detonation 
activities in the project area are not anticipated, thereby limiting 
potential impacts to zooplanktivorous species, including North Atlantic 
right whales.
    In general, impacts to marine mammal prey species from construction 
activities are expected to be minor and temporary due to the expected 
limited daily duration of individual pile driving events and few 
instances (10) of UXO/MEC detonations. Behavioral changes in prey in 
response to construction activities could temporarily impact marine 
mammals' foraging opportunities in a limited portion of the foraging 
range but, because of the relatively small area of the habitat that may 
be affected at any given time (e.g., around a pile being driven) and 
the temporary nature of the disturbance on prey species, the impacts to 
marine mammal habitat from construction activities (i.e., foundation 
installation, UXO/MEC detonation, and HRG surveys) are not expected to 
cause significant or long-term negative consequences.
    Cable presence is not anticipated to impact marine mammal habitat 
as these would be buried, and any electromagnetic fields emanating from 
the cables are not anticipated to result in consequences that would 
impact marine mammals' prey to the extent they would be unavailable for 
consumption.
    The physical presence of WTG foundations and associated scour 
protection within the Lease Area would remain within marine mammal 
habitat for approximately 30 years. The submerged parts of these 
structures act as artificial reefs, providing new habitats and 
restructuring local ecology, likely affecting some prey resources that 
could benefit many species, including some marine mammals. Wind turbine 
presence and/or operations is, in general, likely to result in 
oceanographic effects in the marine environment, and may alter 
aggregations and distribution of marine mammal zooplankton prey and 
other species through changing the strength of tidal currents and 
associated fronts, changes in stratification, primary production, the 
degree of mixing, and stratification in the water column (Schultze et 
al., 2020; Chen et al., 2021; Johnson et al., 2021; Christiansen et 
al., 2022; Dorrell et al., 2022). However, there is significant 
uncertainty regarding the extent to and rate at which changes may 
occur, how potential changes might impact various marine mammal prey 
species (e.g., fish, copepods), and how or if impacts to prey species 
might result in impacts to

[[Page 53798]]

marine mammal foraging that may result in fitness consequences.
    The project would consist of no more than 149 foundations 
supporting 147 WTGs and 2 OSPs in the Lease Area, which will gradually 
become operational (i.e., commissioned) throughout construction of 
Project 1 and Project 2. SouthCoast's construction schedule indicates 
that it is possible that WTGs would not become operational until the 
latter part of the 5-year effective period of the rule, if issued.
Mitigation To Reduce Impacts on All Species
    This proposed rulemaking includes a variety of mitigation measures 
designed to minimize impacts on all marine mammals, with enhanced 
measures focused on North Atlantic right whales (the latter is 
described in more detail below). For impact pile driving of foundation 
piles and UXO/MEC detonations, ten overarching mitigation and 
monitoring measures are proposed, which are intended to reduce both the 
number and intensity of marine mammal takes: (1) seasonal and time of 
day work restrictions; (2) use of multiple PSOs to visually observe for 
marine mammals (with any detection within specifically designated zones 
that would trigger a delay or shutdown); (3) use of PAM to acoustically 
detect marine mammals, with a focus on detecting baleen whales (with 
any detection within designated zones triggering delay or shutdown); 
(4) implementation of clearance zones; (5) implementation of shutdown 
zones; (6) use of soft-start; (7) use of noise attenuation technology; 
(8) maintaining situational awareness of marine mammal presence through 
the requirement that any marine mammal sighting(s) by SouthCoast's 
personnel must be reported to PSOs; (9) sound field verification 
monitoring; and (10) vessel strike avoidance measures to reduce the 
risk of a collision with a marine mammal and vessel. For HRG surveys, 
we are requiring six measures: (1) measures specifically for vessel 
strike avoidance; (2) specific requirements during daytime and 
nighttime HRG surveys; (3) implementation of clearance zones; (4) 
implementation of shutdown zones; (5) use of ramp-up of acoustic 
sources; and (6) maintaining situational awareness of marine mammal 
presence through the requirement that any marine mammal sighting(s) by 
SouthCoast's personnel must be reported to PSOs.
    NMFS has proposed mitigation to reduce the impacts of the specified 
activities on the species and stocks to the extent practicable. The 
Proposed Mitigation section discusses the manner in which the required 
mitigation measures reduce the magnitude and/or severity of the take of 
marine mammals. For pile driving and UXO/MEC detonations, SouthCoast 
would be required to reduce noise levels to the lowest levels 
practicable and implement additional NAS should SFV identify that 
measured distances have exceeded modeled distances to harassment 
threshold isopleths, assuming a 10-dB attenuation. Use of a soft-start 
during impact pile driving will allow animals to move away from the 
sound source prior to applying higher hammer energy levels needed to 
install the pile (this anticipated behavior is accounted for in the 
take estimates given they represent installation of the entire pile at 
various hammer energy levels, including very low energy levels). 
SouthCoast would not use a hammer energy greater than necessary to 
install piles, thereby minimizing exposures to higher sound levels. 
Similarly, ramp-up during HRG surveys would allow animals to move away 
and avoid the acoustic sources before they reach their maximum energy 
level. For pile driving and HRG surveys, clearance zone and shutdown 
zone implementation, which are required when marine mammals are within 
given distances associated with certain impact thresholds for all 
activities, would reduce the magnitude and severity of marine mammal 
take by delaying or shutting down the activity if marine mammals are 
detected within these relevant zones, thus reducing the potential for 
exposure to more disturbing levels of noise. Additionally, the use of 
multiple PSOs (WTG and OSP foundation installation, HRG surveys, and 
UXO/MEC detonations), PAM operators (for impact foundation installation 
and UXO/MEC detonation), and maintaining awareness of marine mammal 
sightings reported in the region (for WTG and OSP foundation 
installation, HRG surveys, and UXO/MEC detonations) would aid in 
detecting marine mammals that would trigger the implementation of the 
mitigation measures. The reporting requirements, including SFV 
reporting (for foundation installation, foundation operation, and UXO/
MEC detonations), will assist NMFS in identifying if impacts beyond 
those analyzed in this proposed rule are occurring, potentially leading 
to the need to enact adaptive management measures in addition to or in 
place of the proposed mitigation measures. Overall, the proposed 
mitigation measures affect the least practicable adverse impact on 
marine mammals from the specified activities.

Mysticetes

    Six mysticete species (comprising six stocks) of cetaceans (North 
Atlantic right whale, humpback whale, blue whale, fin whale, sei whale, 
and minke whale) may be taken by harassment. These species, to varying 
extents, utilize the specified geographicalregion, including the Lease 
Area and ECCs, for the purposes of migration, foraging, and 
socializing. The extent to which any given individual animal engages in 
these behaviors in the area is species-specific, varies seasonally, 
and, in part, is dependent upon the availability of prey (with animals 
generally foraging if the amount of prey necessary to forage is 
available). For example, mysticetes may be migrating through the 
project area towards or from primary feeding habitats (e.g., Cape Cod 
Bay, Stellwagen Bank, Great South Channel, and Gulf of St. Lawrence) 
and calving grounds in the southeast, and thereby spending a very 
limited amount of time in the presence of the specified activities. 
Alternatively, as discussed in the Effects section and in the species-
specific sections below, mysticetes may be engaged in foraging behavior 
over several days. Overall, the mitigation measures, including the 
enhanced seasonal restrictions on pile driving and UXO/MEC detonation, 
are specifically designed to limit, to the maximum extent practical, 
take to those times when species of concern, namely the North Atlantic 
right whale, are most likely to not be engaged in critical behaviors 
such as concentrated foraging.
    As described previously, Nantucket Shoals provides important 
foraging habitat for multiple species. For Projects 1 and 2, the 
ensonified zone extending to the NMFS harassment threshold isopleths 
produced during impact installation of foundations would extend out to 
a distance of 7.4 km (4.6 mi) from each pile as it is installed, 
including from foundations located closest to Nantucket Shoals. While 
vibratory pile driving for Project 2 would result in a larger 
ensonified zone (42 km (26.1 mi)), foundations for that project would 
be located in the southwestern part of the Lease Area, a minimum of 20 
km (12.4 mi) from the 30-m (98.4-ft) isobath on the western edge of 
Nantucket Shoals and vibratory driving would be limited in duration for 
each foundation using this method (up to 90 minutes for each pin pile 
and up to 20 minutes for each monopile). As described in the Effects 
section, distance from a source can be influential on the intensity of 
impact (i.e., the farther a

[[Page 53799]]

marine mammal receiver is from a source, the less intense the expected 
behavioral reaction). In addition, any displacement of whales or 
interruption of foraging bouts would be expected to be relatively 
temporary in nature. Seasonal restrictions on pile driving and UXO/MEC 
detonations would ensure that these activities do not occur during 
prime foraging periods for particular mysticete species, including the 
North Atlantic right whale. Thus, for both projects, the area of 
potential marine mammal disturbance during pile driving does not fully 
spatially and temporally encompass the entirety of any specific 
mysticete foraging habitat.
    Behavioral data on mysticete reactions to pile driving noise are 
scant. Kraus et al. (2019) predicted that the three main impacts of 
offshore wind farms on marine mammals would consist of displacement, 
behavioral disruptions, and stress. Broadly, we can look to studies 
that have focused on other noise sources such as seismic surveys and 
military training exercises, which suggest that exposure to loud 
signals can result in avoidance of the sound source (or displacement if 
the activity continues for a longer duration in a place where 
individuals would otherwise have been staying, which is less likely for 
mysticetes in this area), disruption of foraging activities (if they 
are occurring in the area), local masking around the source, associated 
stress responses, and impacts to prey (as well as TTS or PTS in some 
cases) that may affect marine mammal behavior.
    The potential for repeated exposures is dependent upon the 
residency time of whales, with migratory animals unlikely to be exposed 
on repeated occasions and animals remaining in the area to be more 
likely exposed repeatedly. For mysticetes, where relatively low numbers 
of species-specific take by Level B harassment are predicted (compared 
to the abundance of the mysticete species or stock, such as is 
indicated in table 53) and movement patterns for most species suggest 
that individuals would not necessarily linger around the project area 
for multiple days, each predicted take likely represents an exposure of 
a different individual, with perhaps, for a few species, a subset of 
takes potentially representing a small number of repeated takes of a 
limited number of individuals across multiple days. In other words, the 
behavioral disturbance to any individual mysticete would, therefore, 
likely occur within a single day within a year, or potentially across a 
few days.
    In general, the duration of exposures would not be continuous 
throughout any given day (with an estimated maximum of 8 hours of 
intermittent impact pile driving per day in Project 1, regardless of 
foundation type; up to 8 hours of intermittent impact driving if 2 
monopiles are installed per day using only an impact hammer in Project 
2; up to 5.6 hours of intermittent impact and 40 minutes of of 
vibratory pile driving in Project 2 if installing 2 monopiles requiring 
both installation methods; or up to 6 hours of intermittent impact and 
6 hours of vibratory pile driving if installing 4 pin piles requiring 
both methods). In addition, pile driving would not occur on all 
consecutive days within a given year, due to weather delays or any 
number of logistical constraints SouthCoast has identified. Species-
specific analysis regarding potential for repeated exposures and 
impacts is provided below.
    The fin whale is the only mysticete species for which PTS is 
anticipated and proposed for authorization. As described previously, 
PTS for mysticetes from some project activities may overlap frequencies 
used for communication, navigation, or detecting prey. However, given 
the nature and duration of the activity, the mitigation measures, and 
likely avoidance behavior for pile driving, any PTS is expected to be 
of a small degree, would be limited to frequencies where pile driving 
noise is concentrated (i.e., only a small subset of their expected 
hearing range) and would not be expected to impact reproductive success 
or survival.
North Atlantic Right Whale
    North Atlantic right whales are listed as endangered under the ESA 
and as both depleted and strategic stocks under the MMPA. As described 
in the Potential Effects to Marine Mammals and Their Habitat section, 
North Atlantic right whales are threatened by a low population 
abundance, high mortality rates, and low reproductive rates. Recent 
studies have reported individuals showing high stress levels (e.g., 
Corkeron et al., 2017) and poor health, which has further implications 
on reproductive success and calf survival (Christiansen et al., 2020; 
Stewart et al., 2021; Stewart et al., 2022; Pirotta et al., 2024). As 
described below, a UME has been designated for North Atlantic right 
whales. Given this, the status of the North Atlantic right whale 
population is of heightened concern and, therefore, merits additional 
analysis and consideration. No Level A harassment, serious injury, or 
mortality is anticipated or proposed for authorization for this 
species.
    For North Atlantic right whales, this proposed rule would allow for 
the authorization of up to 149 takes, by Level B harassment, over the 
5-year period, with no more than 111 takes by Level B harassment 
allowed in any single year. The majority of these takes (n=111) would 
likely occur in the year in which SouthCoast proposes to construct 
Project 2 Scenario 2 (73 monopiles), with two-thirds (n=100) occurring 
incidental to impact and vibratory pile driving in the southern portion 
of the Lease Area (farthest from important feeding habitat near 
Nantucket Shoals). Installation using a combination of pile driving 
methods would begin with vibratory pile driving, which is expected to 
occur for 20 minutes per 9/16-m monopile and 90 minutes per 4.5-m pin 
pile, and require fewer impact hammer strikes during the impact 
hammering phase because the pile would already be partially installed 
using vibratory pile driving, thus minimizing use of the installation 
method (i.e., impact pile driving) expected to elicit stronger 
behavioral responses. Although the Level B harassment zone resulting 
from vibratory pile driving is larger (42 km (26.1 mi)) than that 
produced by impact hammering (7.4 km (4.6 mi)), it would extend from 
Project 2 foundation only, thus reducing overlap of the ensonified zone 
with North Atlantic right whale feeding habitat nearer Nantucket 
Shoals. As described in the Potential Effects of the Specified 
Activities on Marine Mammals and Their Habitat section, the best 
available science indicates that distance from a source is an important 
variable when considering both the potential for and the anticipated 
severity of behavioral disturbance from an exposure in that it can have 
an effect on behavioral response that is independent of the effect of 
received level (e.g., DeRuiter et al., 2013; Dunlop et al., 2017a; 
Dunlop et al., 2017b; Falcone et al., 2017; Dunlop et al., 2018; 
Southall et al., 2019a). The maximum number of North Atlantic right 
whale takes that may occur in a given year are primarily driven by 
Project 2, Scenario 2 in which impact and vibratory driving are 
anticipated to result in 100 takes (table 35). The majority of these 
takes are due to extension of the ensonified zone, given the 120-dB 
behavioral threshold for vibratory driving, towards areas with higher 
densities of North Atlantic right whales on Nantucket Shoals. Animals 
exposed to vibratory driving sounds on the Shoals would be tens of 
kilometers from the source; therefore, while NMFS anticipates takes may 
occur, the intensity of take is expected to be minimal and not result 
in behavioral changes that would meaningfully result in impacts that

[[Page 53800]]

could affect the population through annual rates of recruitment or 
survival.
    The maximum number of annual takes (111 total, incidental to all 
activities) equates to approximately 32.8 percent of the stock 
abundance, if each take were considered to be of a different 
individual. However, this is a highly unlikely scenario given the 
reasons described below. Further, far lower numbers of take are 
expected in the years when SouthCoast is not installing foundations 
(e.g., years when only HRG surveys would be occurring). For Project 1, 
only 12 takes (approximately 8 percent of all 149 takes) would be 
incidental to installation of foundations using impact pile driving as 
the only installation method, the activity NMFS anticipates would 
result in the most intense behavioral responses. A small number of 
Level B harassment takes (23) would occur incidental to HRG surveys 
over 5 years, an activity for which the maximum size ensonified zone is 
very small (141 m (462.6 ft)) and the severity of any behavioral 
harassment is expected to be very low. The remaining takes (17) would 
occur incidentally to 10 instantaneous UXO/MEC detonations, should they 
occur. SouthCoast would detonate UXO/MECs as a last resort, only after 
attempting every other option available, including avoidance (i.e., 
working around the UXO/MEC location in the project area). SouthCoast's 
proposed seasonal restriction on this activity (December 1-April 30) 
would significantly reduce the potential that detonation events occur 
when North Atlantic right whales are expected to be most frequent in 
Southern New England region, and the required extensive clearance 
process prior to detonation would help ensure no right whales were 
within the portion of the Lease Area or ECC where the planned 
detonation would occur, minimizing the potential for more severe TTS 
(e.g., longer lasting and of higher shift) or behavioral reaction. 
Detonations, if required, would be instantaneous, further limiting the 
probability of exposure to sound levels likely to result in TTS or more 
severe behavioral reactions. In consideration of the enhanced 
mitigation measures, including the extensive monitoring proposed to 
detect North Atlantic right whales to enact such mitigation, the Level 
B harassment takes proposed for authorization are expected to elicit 
only minor behavioral responses (e.g., avoidance, temporary cessation 
of foraging) and not result in impacts to reproduction and survival.
    As previously described, it is long-established that coastal waters 
in SNE are part of a known migratory corridor for North Atlantic right 
whales, but over the past decade or more, it has become increasingly 
clear that suitable foraging habitat exists in the area as well. In 
addition to increased occurrence (understood through visual and PAM 
detection data) in the area, the number of DMAs declared in the area 
has also increased in recent years. Foraging North Atlantic right 
whales, particularly those in groups of 3 or more, often remain in a 
feeding area for up to 2 weeks (this is the basis for defining DMAs), 
meaning individual whales may be using SNE habitat for extended 
periods. The region has been also been characterized as an important 
transition region (i.e., a stopover site for migrating North Atlantic 
right whales moving to or from southeastern calving grounds and more 
northern feeding grounds, as well as a feeding location utilized at 
other times of the year by individuals (Quintana-Rizzo et al., 2021; 
O'Brien et al., 2022). Additional qualitative observations in southern 
New England include animals socializing (Quintana-Rizzo et al., 2021). 
As described in the Potential Effects of the Specified Activities on 
Marine Mammals and Their Habitat section, North Atlantic right whales 
range outside of the project area for their main feeding, breeding, and 
calving activities; however, the importance of Southern New England, 
particularly the Nantucket Shoals area, for critical behaviors such as 
foraging, warranted the enhanced mitigation measures described in this 
proposed rule to minimize the potential impacts on North Atlantic right 
whales.
    Quintana-Rizzo et al. (2021) noted different degrees of residency 
(i.e., the minimum number of days an individual remained in southern 
New England) for right whales, with individual sighting frequency 
ranging from 1 to 10 days, annually. Resightings (i.e., observation of 
the same individual on separate occasions) occurred most frequently 
from December through May. Model outputs suggested that, during these 
months, 23 percent of the species' population was present in this 
region, and that the mean residence time tripled between their study 
periods (i.e., December through May, 2011-2015 compared to 2017-2019) 
to an average of 13 days during these months. The seasonal restriction 
on pile driving for both Projects 1 and 2 includes this period, thus 
reducing the potential for repeated exposures of individual right 
whales during either project because whales are not expected to persist 
in the project area to the same extent during the months pile driving 
would occur. The more extensive seasonal restriction within the NARW 
EMA (October 16-May 31 would further reduce this possibility, although 
the increased likelihood of foraging activity closer to Nantucket 
Shoals might create the potential for repeated exposures, should whales 
linger there to forage despite the occurrence of construction 
activities in the vicinity. Across all years, if an individual were 
exposed during a subsequent year, the impact of that exposure is likely 
independent of the previous exposure given the expectation that impacts 
to marine mammals from project activities would generally be temporary 
(i.e., minutes to hours) and of low severity, coupled with the 
extensive duration between exposures. However, the extensive mitigation 
and monitoring measures SouthCoast would be required to implement, 
including delaying or ceasing pile driving for 24 to 48 hours 
(depending on the number of animals sighted and time of year) if 
SouthCoast observes a North Atlantic right whale at any distance or 
acoustically detects a right whale within the 10-km (6.2-mi) (pin pile) 
or 15-km (9.3-mi) (monopile) PAM clearance/shutdown zone, are expected 
to reduce impacts should take occur.
    Quintana-Rizzo et al. (2021) noted that North Atlantic right whale 
sightings during the 2017-2019 study period were primarily concentrated 
in the southeastern sections of the MA WEA, throughout the northeast 
section of the Lease Area and areas south of Nantucket, during winter 
(December-February), shifted northwest towards Martha's Vineyard and 
the RI/MA WEA in spring (March-May), and to the east higher up on 
Nantucket Shoals in the summer (June-August) (Quintano-Rizzo et al., 
2021). Summer and fall sightings did not occur in 2011-2015, and only a 
small number of right whales were sighted south of Nantucket (Quintana-
Rizzo et al., 2021). In PAM data collected in southern New England from 
2020 through 2022, acoustic detections of North Atlantic right whales 
occurred most frequently from November through April, and less 
frequently from May through mid-October, particularly in recordings 
collected on the eastern edge of the WEAs, within the NARW EMA, 
compared to recordings collected in western southern New England (van 
Parijs et al., 2023; Davis et al., 2023). Placing a moratorium on pile 
driving in the NARW EMA from Oct 16-May 31 would minimize exposures of 
right whales to pile driving noise, and any potential associated 
foraging disruptions, by avoiding foundation installation when right 
whales are most prevalent and most likely to be engaged

[[Page 53801]]

in foraging in that part of the project area, as well as minimizing the 
potential for multiple exposures per individual given pile driving 
would not occur when residency times are expected to be extended based 
on resighting frequency and acoustic persistence data (Quintano-Rizzo 
et al., 2021; Davis et al., 2023). Similarly, seasonally restricting 
pile driving from January 1-May 15, annually, outside of the NARW EMA 
(applicable to a portion of Project 1 foundations and all of Project 2 
foundations), would extend the area over which pile driving is limited 
during the period of peak right whale abundance in southern New 
England, thus limiting exposures and temporary foraging disturbances 
more broadly. Similarly, restricting UXO/MEC detonations from December 
1-April 30 ensures that this activity would not occur when North 
Atlantic right whales utilize habitat in the project area most often. 
Although HRG surveys would not be subject to seasonal restrictions, 
impacts from Level B harassment would be minimal given the low numbers 
of take proposed for authorization and very small harassment zone.
    In summary, North Atlantic right whales in the project area are 
expected to be predominately engaging in migratory behavior during the 
spring and fall, foraging behavior primarily in late winter and spring 
(and, to some degree, throughout the year), and social behavior during 
winter and spring (Quintana-Rizzo et al., 2021). Within the project 
area, North Atlantic right whale occurrence and foraging are both 
expected to be most extensive near Nantucket Shoals, along the eastern 
edge of the MA WEA within the NARW EMA. Given the species' migratory 
behavior and occurrence patterns, we anticipate individual whales would 
typically utilize specific habitat in the project area (inside and 
outside the NARW EMA), primarily during months when foundation 
installation and UXO/MEC detonation would not occur (given the specific 
time/area restrictions on these activities specific to inside, and 
outside, the NARW EMA). It is important to note the activities that 
could occur from December through May (i.e., are not seasonally 
restricted) that may impact North Atlantic right whales using the 
habitat for foraging would be primarily HRG surveys, with very small 
Level B harassment zones (less than 150 m) due to rapid transmission 
loss of the sounds produced neither of which would result in very high 
received levels. While UXO/MEC detonation may occur in November or May, 
the number of UXO/MECs are expected to be very minimal (if any) and 
would be instantaneous in nature; thereby, resulting in short term, 
minimal impacts with any TTS that may occur recovering quickly.
    As described in the Description of Marine Mammals in the Specified 
Geographic Area section of this preamble, North Atlantic right whales 
are presently experiencing an ongoing UME (beginning in June 2017). 
Preliminary findings support human interactions, specifically vessel 
strikes and entanglements, as the cause of death for the majority of 
North Atlantic right whales. Given the current status of the North 
Atlantic right whale, the loss of even one individual could 
significantly impact the population. Any disturbance to North Atlantic 
right whales due to SouthCoast's activities is expected to result in 
temporary avoidance of the immediate area of construction. As no 
injury, serious injury, or mortality is expected or proposed for 
authorization and Level B harassment of North Atlantic right whales 
will be reduced to the lowest level practicable (both in magnitude and 
severity) through use of mitigation measures, the proposed number of 
takes of North Atlantic right whales would not exacerbate or compound 
the effects of the ongoing UME.
    As described in the general Mysticetes section above, foundation 
installation is likely to result in the greatest number of annual takes 
and is of greatest concern given loud source levels. This activity 
would be most extensively limited to locations outside of the NARW EMA 
and during times when, based on the best available science, North 
Atlantic right whales are less frequently encountered in the NARW EMA 
and less likely to be engaged in critical foraging behavior (although 
NMFS recognizes North Atlantic right whales may forage year-round in 
the project area). Temporal limits on foundation installation outside 
of the NARW EMA are similarly defined by expectations, based on the 
best available science, that North Atlantic right whale occurrence 
would be lowest when pile driving would occur.
    The potential types, severity, and magnitude of impacts are also 
anticipated to mirror that described in the general Mysticetes section 
above, including avoidance (the most likely outcome), changes in 
foraging or vocalization behavior, masking, and temporary physiological 
impacts (e.g., change in respiration, change in heart rate). Although a 
small amount of TTS is possible, it is not likely. Importantly, given 
the enhanced mitigation measures specific to North Atlantic right 
whales, the effects of the activities are expected to be sufficiently 
low-level and localized to specific areas as to not meaningfully impact 
important migratory or foraging behaviors for North Atlantic right 
whales. These takes are expected to result in temporary behavioral 
disturbance, such as slight displacement (but not abandonment) of 
migratory habitat or temporary cessation of feeding.
    In addition to the general mitigation measures discussed earlier in 
the Preliminary Negligible Impact Analysis section, to provide enhanced 
protection for right whales and minimize the number and/or severity of 
exposures, SouthCoast would be required to implement conditionally-
triggered protocols in response to sightings or acoustic detections of 
North Atlantic right whales. If one or two North Atlantic right whales 
is/are sighted or if PAM operators detect a right whale vocalization, 
pile driving would be suspended until the next day, commencing only 
after SouthCoast conducts a vessel-based survey of the zone around the 
pile driving location (10-km (6.2-mi) zone for pin pile; 15-km (9.3-mi) 
zone for monopile) to ensure the zone is clear of North Atlantic right 
whales. Pile driving would be delayed for 482 days following a sighting 
of 3 or more whales (more likely indicative of a potential feeding 
aggregation), followed by the same survey requirement prior to 
commencing foundation installation. Further, given many of these 
exposures are generally expected to occur to different individual right 
whales migrating through (i.e., many individuals would not be impacted 
on more than one day in a year), with some subset potentially being 
exposed on no more than a few days within the year, they are unlikely 
to result in energetic consequences that could affect reproduction or 
survival of any individuals.
    Overall, NMFS expects that any behavioral harassment of North 
Atlantic right whales incidental to the specified activities would not 
result in changes to their migration patterns or foraging success, as 
only temporary avoidance of an area during construction is expected to 
occur. As described previously, North Atlantic right whales migrate, 
forage, and socialize in the Lease Area, but are not expected to remain 
in this habitat (i.e., not expected to be engaged in extensive foraging 
behavior) for prolonged durations during the months SouthCoast would 
install foundations, considering the seasonal restrictions SouthCoast 
proposed and NMFS would require, relative to habitats to the north, 
such as Cape Cod Bay, the Great South

[[Page 53802]]

Channel, and the Gulf of St. Lawrence (Mayo, 2018; Quintana-Rizzo et 
al., 2021; Meyer-Gutbrod et al., 2022; Plourde et al., 2024). Any 
temporarily displaced animals would be able to return to or continue to 
travel through the project area and subsequently utilize this habitat 
once activities have ceased.
    Although acoustic masking may occur in the vicinity of the 
foundation installation activities, based on the acoustic 
characteristics of noise associated with impact pile driving (e.g., 
frequency spectra, short duration of exposure) and construction surveys 
(e.g., intermittent signals), NMFS expects masking effects to be 
minimal. Given that the majority of Project 1 foundations would be 
located within the NARW EMA, where North Atlantic right whales are most 
likely to occur throughout the year, SouthCoast decided to use the 
installation method that resulted in a smaller ensonified zone (i.e., 
impact pile driving). Foundations would be installed farther from the 
NARW EMA in the southwestern half of the Lease Area for Project 2, 
thus, if vibratory pile driving occurs, the Level B harassment zone 
would not overlap this high-use area to the same extent. In addition, 
the most severe masking impacts would likely occur when a North 
Atlantic right whale is in relatively close proximity to the pile 
driving location, which would be minimized given the requirement that 
pile driving must be delayed or shutdown if a North Atlantic right 
whale is sighted at any distance or acoustically detected within the 
PAM clearance or shutdown zones (10-km (6.2-mi) or 15-km (9.3-mi)) 
during installation of 4.5-m pin piles or 9/16-m monopiles, 
respectively). In addition, both pile driving methods are expected to 
occur intermittently within a day and be confined to the months in 
which North Atlantic right whales occur at lower densities. Any masking 
effects would be minimized by anticipated mitigation effectiveness and 
likely avoidance behaviors.
    As described in the Potential Effects to Marine Mammals and Their 
Habitat section of this preamble, the distance of the receiver to the 
source influences the severity of response with greater distances 
typically eliciting less severe responses. NMFS recognizes North 
Atlantic right whales migrating could be pregnant females (in the fall) 
and cows with older calves (in spring) and that these animals may 
slightly alter their migration course in response to any foundation 
pile driving; however, we anticipate that course diversion would be of 
small magnitude. Hence, while some avoidance of the pile driving 
activities may occur, we anticipate any avoidance behavior of migratory 
North Atlantic right whales would be similar to that of gray whales 
(Tyack et al., 1983), on the order of hundreds of meters up to 1 to 2 
km. This diversion from a migratory path otherwise uninterrupted by 
project activities is not expected to result in meaningful energetic 
costs that would impact annual rates of recruitment or survival. NMFS 
expects that North Atlantic right whales would be able to avoid areas 
during periods of active noise production while not being forced out of 
this portion of their habitat.
    North Atlantic right whale presence in the project area is year-
round. However, abundance during summer months is lower compared to the 
winter months, with spring and fall serving as ``shoulder seasons'' 
wherein abundance waxes (fall) or wanes (spring). Given this year-round 
habitat usage, in recognition that where and when whales may actually 
occur during project activities is unknown, as it depends on the annual 
migratory behaviors, SouthCoast has proposed and NMFS is proposing to 
require a suite of mitigation measures designed to reduce impacts to 
North Atlantic right whales to the maximum extent practicable. These 
mitigation measures (e.g., seasonal/daily work restrictions, vessel 
separation distances, reduced vessel speed, increased monitoring 
effort) would not only avoid the likelihood of vessel strikes but also 
would minimize the severity of behavioral disruptions by minimizing 
impacts (e.g., through sound reduction using noise attenuation systems 
and reduced temporal and spatial overlap of project activities and 
North Atlantic right whales). This would further ensure that the number 
of takes by Level B harassment that are estimated to occur are not 
expected to affect reproductive success or survivorship by impacts to 
energy intake or cow/calf interactions during migratory transit. 
However, even in consideration of recent habitat-use and distribution 
shifts, SouthCoast would still be installing foundations when the 
occurrence of North Atlantic right whales is expected to be lower.
    As described in the Description of Marine Mammals in the Specified 
Geographic Area section of this preamble, SouthCoast Project would be 
constructed within the North Atlantic right whale migratory corridor 
BIA, which represents areas and months within which a substantial 
portion of a species is known to migrate. The Lease Area is relatively 
narrow compared to the width of the North Atlantic right whale 
migratory corridor BIA (approximately 47.5 km (29.5 mi) versus 
approximately 300 km (186 mi), respectively, at the furthest points 
near the Lease Area). Because of this, overall North Atlantic right 
whale migration is not expected to be impacted by the proposed 
activities. There are no known North Atlantic right whale mating or 
calving areas within the project area. Although the project area 
includes foraging habitat, extensive mitigation measures would minimize 
impacts by temporally and spatially reducing co-occurrence of project 
activities and feeding North Atlantic right whales. Prey species (e.g., 
calanoid copepods) are more broadly distributed throughout southern New 
England during periods when pile driving and UXO/MEC detonation would 
occur (noting again that North Atlantic right whale prey is not 
particularly concentrated in the project area relative to nearby 
habitats). Therefore, any impacts to prey that may occur during the 
effective period of these regulations are also unlikely to impact 
marine mammals in a manner that would affect reproduction or survival 
of any individuals.
    The most significant measure to minimize impacts to individual 
North Atlantic right whales is the seasonal moratorium on all 
foundation installation activities in the NARW EMA from October 16 
through May 31, annually, and throughout the rest of the Lease Area 
from January 1 through May 15, as well as the limitation on these 
activities in December (e.g., only work with approval from NMFS), when 
North Atlantic right whale abundance in the Lease Area is expected to 
be highest. NMFS also expects this measure to greatly reduce the 
potential for mother-calf pairs to be exposed to impact pile driving 
noise above the Level B harassment threshold during their annual spring 
migration through the project area from calving grounds to primary 
foraging grounds (e.g., Cape Cod Bay). UXO/MEC detonations would also 
be restricted from December 1 through April 30, annually. NMFS also 
expects that the severity of any take of North Atlantic right whales 
would be reduced due to the additional proposed mitigation measures 
that would ensure that any exposures above the Level B harassment 
threshold would result in only short-term effects to individuals 
exposed.
    Pile driving and UXO/MEC detonations may only begin in the absence 
of North Atlantic right whales (based on visual and passive acoustic 
monitoring). If pile driving has commenced, NMFS anticipates North 
Atlantic right whales would avoid the area, utilizing nearby waters to 
carry on

[[Page 53803]]

pre-exposure behaviors. However, foundation installation activities 
must be shut down if a North Atlantic right whale is sighted at any 
distance or acoustically detected at any distance within the PAM 
shutdown zone, unless a shutdown is not feasible due to risk of injury 
or loss of life. If a sighting of a North Atlantic right whale within 
the Level B harassment zone triggers shutdown, both the duration and 
intensity of exposure would be reduced. NMFS anticipates that if North 
Atlantic right whales are exposed to foundation installation or UXO/MEC 
detonation noise, it is unlikely a North Atlantic right whale would 
approach the sound source locations to the degree that they would 
purposely expose themselves to very high noise levels. This is because 
observations of typical whale behavior demonstrate likely avoidance of 
harassing levels of sound where possible (Richardson et al., 1985). 
These measures are designed to avoid PTS and also reduce the severity 
of Level B harassment, including the potential for TTS. While some TTS 
could occur, given the mitigation measures (e.g., delay pile driving 
upon a sighting or acoustic detection and shutting down upon a sighting 
or acoustic detection), the potential for TTS to occur is low and, as 
described above for all mysticetes, any TTS would be expected to be of 
a relatively short duration and small degree.
    The proposed clearance and shutdown measures are most effective 
when detection efficiency is maximized, as the measures are triggered 
by a sighting or acoustic detection. To maximize detection efficiency, 
SouthCoast proposed and NMFS is proposing to require the combination of 
PAM and visual observers. In addition, NMFS is proposing to require 
communication protocols with other project vessels and other heightened 
awareness efforts (e.g., daily monitoring of North Atlantic right whale 
sighting databases) such that as a North Atlantic right whale 
approaches the source (and thereby could be exposed to higher noise 
energy levels), PSO detection efficacy would increase, the whale would 
be detected, and a delay to commencing pile driving or shutdown (if 
feasible) would occur. NMFS is proposing to require that, during three 
timeframes (NARW EMA: August 1-Oct 15; outside NARW EMA: May 16-May 31 
and December 1-31), SouthCoast deploy four dedicated PSO vessels, each 
with three on-duty PSOs, to monitor before, during, and after pile 
driving for right whale sightings ``at any distance.'' For all other 
foundation installation timeframes (NARW EMA: June 1-July 31; outside 
NARW EMA: June 1-November 30) NMFS would require that this monitoring 
be conducted by a minimum 3 PSOs on each of three dedicated PSO 
vessels. By increasing the extent of monitoring platforms and 
observers, and thereby the detection efficacy, exposures would be 
minimized because North Atlantic right whales would be detected at 
greater distances, prompting delay or shutdown before the whale enters 
the Level B harassment zone.
    Given that specific locations for the 10 possible UXOs/MECs are not 
presently known, SouthCoast has agreed to undertake specific mitigation 
measures to reduce impacts on any North Atlantic right whales, 
including delaying a UXO/MEC detonation if a North Atlantic right whale 
is visually observed or acoustically detected at any distance. The UXO/
MEC detonations mitigation measures described above would further 
reduce the potential to be exposed to high received levels.
    For HRG surveys, the maximum distance to the Level B harassment 
isopleth is 141 m (462.6 ft). Because of the short maximum distance to 
the Level B harassment isopleth, the requirement that vessels maintain 
a distance of 500 m (1,640.4 ft) from any North Atlantic right whale, 
the fact whales are unlikely to remain in close proximity to an HRG 
survey vessel for any length of time, and that the acoustic source 
would be shutdown if a North Atlantic right whale is observed within 
500 m (1,640.4 ft) of the source, any exposure to noise levels above 
the Level B harassment threshold (if any) would be very brief. To 
further minimize exposures, ramp-up of boomers, sparkers, and CHIRPs 
must be delayed during the clearance period if PSOs detect a North 
Atlantic right whale within 500 m (1,640.4 ft) of the acoustic source. 
Due to the nature of the activity, and with implementation of the 
proposed mitigation requirements, take by Level A harassment is 
unlikely and, therefore, not proposed for authorization. Potential 
impacts associated with Level B harassment would include low-level, 
temporary behavioral modifications, most likely in the form of 
avoidance behavior. Given the high level of precautions taken to 
minimize both the amount and intensity of Level B harassment on North 
Atlantic right whales, it is unlikely that the anticipated low-level 
exposures would lead to reduced reproductive success or survival for 
any individual North Atlantic right whales.
    Given the documented habitat use within the area within the 
timeframe foundation installations and UXO/MEC detonations may occur, a 
subset of these takes may represent multiple exposures of some number 
of individuals than is the case for other mysticetes, though some takes 
may also represent one-time exposures to an individual the majority of 
the individuals taken would be impacted on only one day in a year, with 
a small subset potentially impacted on no more than a few days a year 
and, further, low level impacts are generally expected from any North 
Atlantic right whale exposure. The magnitude and severity of harassment 
are not expected to result in impacts on the reproduction or survival 
of any individuals, let alone have impacts on annual rates of 
recruitment or survival of this stock.
    Given the low magnitude and severity of the impacts from the take 
proposed for authorization discussed above and in consideration of the 
proposed mitigation and other information presented, SouthCoast's 
specified activities during the proposed effective period of the rule 
are not expected to result in impacts on the reproduction or survival 
of any individuals, or affect annual rates of recruitment or survival. 
For these reasons, we have preliminarily determined that the take by 
Level B harassment only anticipated and proposed for authorization 
would have a negligible impact on the North Atlantic right whale.
    Of note, there is significant uncertainty regarding the impacts of 
turbine foundation presence and operation on the oceanographic 
conditions that serve to aggregate prey species for North Atlantic 
right whales and--given SouthCoast's proximity to Nantucket Shoals--it 
is possible that the expanded analysis of turbine presence and/or 
operation over the life of the project developed for the ESA biological 
opinion for the proposed SouthCoast project or additional information 
received during the public comment period will necessitate 
modifications to the proposed analysis, mitigation and monitoring 
measures, and/or this finding. For example, it is possible that 
additional information or analysis could result in a determination that 
changes in the oceanographic conditions that serve to aggregate North 
Atlantic right whale prey may result in impacts that would qualify as a 
take under the MMPA for North Atlantic right whales.
Blue Whale
    The blue whale is listed as endangered under the ESA, and the 
Western North Atlantic stock is considered depleted and strategic under 
the MMPA. There are no known areas of specific biological importance in 
or

[[Page 53804]]

around the project area, and there is no ongoing UME. The actual 
abundance of the stock is likely significantly greater than what is 
reflected in the SAR because the most recent population estimates are 
primarily based on surveys conducted in U.S. waters and the stock's 
range extends well beyond the U.S. EEZ. No serious injury or mortality 
is anticipated or authorized for this species.
    The rule allows up to nine takes of blue whales, by Level B 
harassment, over the 5-year period. The maximum annual allowable number 
of takes by Level B harassment is three, which equates to approximately 
0.75 percent of the stock abundance if each take were considered to be 
of a different individual. Based on the migratory nature of blue whales 
and the fact that there are neither feeding nor reproductive areas 
documented in or near the project area, and in consideration of the 
very low number of predicted annual takes, it is unlikely that the 
predicted instances of takes would represent repeat takes of any 
individual--in other words, each take likely represents one whale 
exposed on 1 day within a year.
    With respect to the severity of those individual takes by Level B 
harassment, we would anticipate impacts to be limited to low-level, 
temporary behavioral responses with avoidance and potential masking 
impacts in the vicinity of the foundation installation to be the most 
likely type of response. Any potential TTS would be concentrated at 
half or one octave above the frequency band of pile driving noise (most 
sound is below 2 kHz) which does not include the full predicted hearing 
range of blue whales. Any hearing ability temporarily impaired from TTS 
is anticipated to return to pre-exposure conditions within a relatively 
short time period after the exposures cease. Any avoidance of the 
project area due to the activities would be expected to be temporary.
    Given the magnitude and severity of the impacts discussed above, 
and in consideration of the required mitigation and other information 
presented, SouthCoast's activities are not expected to result in 
impacts on the reproduction or survival of any individuals, much less 
affect annual rates of recruitment or survival. For these reasons, we 
have preliminarily determined that the take by Level B harassment 
anticipated and proposed to be authorized will have a negligible impact 
on the western North Atlantic stock of blue whales.
Fin Whale
    The fin whale is listed as endangered under the ESA, and the 
western North Atlantic stock is considered both depleted and strategic 
under the MMPA. No UME has been designated for this species or stock.
    The rule proposes to authorize up to 572 takes, by harassment only, 
over the 5-year effective period. The maximum annual allowable take by 
Level A harassment and Level B harassment, is 3 and 496, respectively 
(combined, this annual take (n=499) equates to approximately 7.34 
percent of the stock abundance, if each take were considered to be of a 
different individual), with far lower numbers than that expected in the 
years without foundation installation (e.g., years when only HRG 
surveys would be occurring). Given the months the project will occur 
and that southern New England is generally considered a feeding 
habitat, it is likely that some subset of the individual whales exposed 
could be taken several times annually.
    Level B harassment is expected to be in the form of behavioral 
disturbance, primarily resulting in avoidance of the Lease Area where 
foundation installation is occurring, potential disruption of feeding, 
and some low-level TTS and masking that may limit the detection of 
acoustic cues for relatively brief periods of time. Any potential PTS 
would be minor (limited to a few dB) and any TTS would be of short 
duration and concentrated at half or one octave above the frequency 
band of pile driving noise (most sound is below 2 kHz) which does not 
include the full predicted hearing range of fin whales.
    Fin whales are present in the waters off of New England year-round 
and are one of the most frequently observed large whales and cetaceans 
in continental shelf waters, principally from Cape Hatteras, North 
Carolina in the Mid-Atlantic northward to Nova Scotia, Canada 
(Sergeant, 1977; Sutcliffe and Brodie, 1977; CETAP, 1982; Hain et al., 
1992; Geo-Marine, 2010; BOEM, 2012; Edwards et al., 2015; Hayes et al., 
2022). In the project area, fin whales densities are highest in the 
winter and summer months (Roberts et al., 2023) though detections do 
occur in spring and fall (Watkins et al., 1987; Clark and Gagnon, 2002; 
Geo-Marine, 2010; Morano et al., 2012). However, fin whales feed more 
extensively in waters in the Great South Channel north to the Gulf 
Maine into the Gulf of St. Lawrence, areas north and east of the 
project area (Hayes et al., 2024).
    As discussed previously, the majority of project area is located to 
the east of small fin whale feeding BIA (2,933 km\2\ (724,760.1 acres)) 
east of Montauk Point, New York (Figure 2.3 in LaBrecque et al., 2015) 
that is active from March to October. Except for a small section of the 
Brayton Point route, the Lease Area and the ECCs do not overlap the fin 
whale feeding BIA. However, if vibratory pile driving is used for 
Project 2, the ensonified zone resulting from installation of the 
closest foundations could extend into the southeastern side of the BIA. 
Foundation installations and UXO/MEC detonations have seasonal work 
restrictions (i.e., spatial and temporal) such that the temporal 
overlap between these specified activities and the active BIA timeframe 
would exclude the months of March and April. A separate larger year-
round feeding BIA (18,015 km\2\ (4,451,603.4 acres)) located to the 
east in the southern Gulf of Maine does not overlap with the project 
area and would thus not be impacted by project activities. We 
anticipate that if foraging is occurring in the project area and 
foraging whales are exposed to noise levels of sufficient strength, 
they would avoid the project area and move into the remaining area of 
the feeding BIA that would be unaffected to continue foraging without 
substantial energy expenditure or, depending on the time of year, 
travel south towards New York Bight foraging habitat or northeast to 
the larger year-round feeding BIA.
    Given the documented habitat use within the area, some of the 
individuals taken would likely be exposed on multiple days. However, 
low level impacts are generally expected from any fin whale exposure. 
Given the magnitude and severity of the impacts discussed above 
(including no more than 566 takes of the course of the 5-year rule, and 
a maximum annual allowable take by Level A harassment and Level B 
harassment, of 3 and 496, respectively), and in consideration of the 
required mitigation and other information presented, SouthCoast's 
activities are not expected to result in impacts on the reproduction or 
survival of any individuals, much less affect annual rates of 
recruitment or survival. For these reasons, we have determined that the 
take by harassment anticipated and proposed for authorization will have 
a negligible impact on the western North Atlantic stock of fin whales.
Sei Whale
    Sei whales are listed as endangered under the ESA, and the Nova 
Scotia stock is considered both depleted and strategic under the MMPA. 
There are no known areas of specific biological importance in or 
adjacent to the project

[[Page 53805]]

area, and no UME has been designated for this species or stock. No 
serious injury or mortality is anticipated or authorized for this 
species.
    The rule authorizes up to 67 takes by harassment over the 5-year 
period. No Level A harassment is anticipated for proposed for 
authorization. The maximum annual allowable take by Level B harassment 
is 48, which equates to approximately 0.8 percent of the stock 
abundance, if each take were considered to be of a different 
individual), with far lower numbers than that expected in the years 
without foundation installation (e.g., years when only HRG surveys 
would be occurring). As described in the Description of Marine Mammals 
in the Specified Geographic Area section of this preamble, most of the 
sei whale distribution is concentrated in Canadian waters and 
seasonally in northerly U.S. waters, although they are uncommonly 
observed as far south as the waters off of New York. Because sei whales 
are migratory and their known feeding areas are east and north of the 
project area (e.g., there is a feeding BIA in the Gulf of Maine), they 
would be more likely to be moving through and, considering this and the 
very low number of total takes, it is unlikely that any individual 
would be exposed more than once within a given year.
    With respect to the severity of those individual takes by Level B 
harassment, we anticipate impacts to be limited to low-level, temporary 
behavioral responses with avoidance and potential masking impacts in 
the vicinity of the WTG installation to be the most likely type of 
response. Any potential PTS and TTS would likely be concentrated at 
half or one octave above the frequency band of pile driving noise (most 
sound is below 2 kHz) which does not include the full predicted hearing 
range of sei whales. Moreover, any TTS would be of a small degree. Any 
avoidance of the project area due to the Project's activities would be 
expected to be temporary.
    Given the magnitude and severity of the impacts discussed above 
(including no more than 67 takes of the course of the 5-year rule, and 
a maximum annual allowable take of 0 by Level A harassment and 48 by 
Level B harassment), and in consideration of the required mitigation 
and other information presented, SouthCoast's activities are not 
expected to result in impacts on the reproduction or survival of any 
individuals, much less affect annual rates of recruitment or survival. 
For these reasons, we have preliminarily determined that the take by 
harassment anticipated and proposed to be authorized will have a 
negligible impact on the Nova Scotia stock of sei whales.
Minke Whale
    Minke whales are not listed under the ESA, and the Canadian East 
Coast stock is neither considered depleted nor strategic under the 
MMPA. There are no known areas of specific biological importance in or 
adjacent to the project area. As described in the Description of Marine 
Mammals in the Specific Geographic Area section of this preamble, a UME 
has been designated for this species but is pending closure. No serious 
injury or mortality is anticipated or authorized for this species.
    The rule authorizes up to 1,162 takes by Level B harassment over 
the 5-year period. No Level A harassment is anticipated or proposed for 
authorization. The maximum annual allowable take by Level B harassment 
is 911, which equates to approximately 4 percent of the stock 
abundance, if each take were considered to be of a different 
individual), with far lower numbers than that expected in the years 
without foundation installation (e.g., years when only HRG surveys 
would be occurring). As described in the Description of Marine Mammals 
in the Specified Geographic Area section, minke whales inhabit coastal 
waters during much of the year and are common offshore the U.S. Eastern 
Seaboard with a strong seasonal component in the continental shelf and 
in deeper, off-shelf waters (CETAP, 1982; Hayes et al., 2022; Hayes et 
al., 2024). Spring through fall are times of relatively widespread and 
common acoustic occurrence on the continental shelf. From September 
through April, minke whales are frequently detected in deep-ocean 
waters throughout most of the western North Atlantic (Clark and Gagnon, 
2002; Risch et al., 2014; Hayes et al., 2024). Minke whales were 
detected in southern New England primarily in the spring and fall, with 
few detections in the summer and winter. In eastern southern New 
England, near the project area, acoustic detections were most frequent 
from April through mid-June (van Parijs et al., 2023). Because minke 
whales are migratory and their known feeding areas are north and east 
of the project area, including a feeding BIA in the southwestern Gulf 
of Maine and George's Bank, they would be more likely to be transiting 
through (with each take representing a separate individual), though it 
is possible that some subset of the individual whales exposed could be 
taken up to a few times annually.
    As previously detailed in the Description of Marine Mammals in the 
Specified Geographic Area section, there is a UME for minke whales 
along the Atlantic coast, from Maine through South Carolina, with the 
highest number of deaths in Massachusetts, Maine, and New York. 
Preliminary findings in several of the whales have shown evidence of 
human interactions or infectious diseases. However, we note that the 
population abundance is approximately 22,000, and the take by Level B 
harassment authorized through this action is not expected to exacerbate 
the UME.
    We anticipate the impacts of this harassment to follow those 
described in the general Mysticetes section above. Any TTS would be of 
short duration and concentrated at half or one octave above the 
frequency band of pile driving noise (most sound is below 2 kHz) which 
does not include the full predicted hearing range of minke whales. 
Level B harassment would be temporary, with primary impacts being 
temporary displacement of the project area but not abandonment of any 
migratory or foraging behavior.
    Given the magnitude and severity of the impacts discussed above 
(including no more than 1,162 takes of the course of the 5-year rule, 
and a maximum annual allowable take by Level A harassment and Level B 
harassment, of 0 and 911, respectively), and in consideration of the 
required mitigation and other information presented, SouthCoast's 
activities are not expected to result in impacts on the reproduction or 
survival of any individuals, much less affect annual rates of 
recruitment or survival. For these reasons, we have preliminarily 
determined that the take by harassment anticipated and proposed for 
authorized will have a negligible impact on the Canadian Eastern 
Coastal stock of minke whales.
Humpback Whale
    The West Indies Distinct Population Segments (DPS) of humpback 
whales is not listed as threatened or endangered under the ESA but the 
Gulf of Maine stock, which includes individuals from the West Indies 
DPS, is considered strategic under the MMPA. However, as described in 
the Description of Marine Mammals in the Specified Geographic Area 
section of this preamble to the rule, humpback whales along the 
Atlantic Coast have been experiencing an active UME as elevated 
humpback whale mortalities have occurred along the Atlantic coast from 
Maine through Florida since January 2016. Of the cases examined, 
approximately 40 percent had evidence of human interaction

[[Page 53806]]

(vessel strike or entanglement). Take from vessel strike and 
entanglement is not authorized. Despite the UME, the relevant 
population of humpback whales (the West Indies breeding population, or 
DPS of which the Gulf of Maine stock is a part) remains stable at 
approximately 12,000 individuals.
    NMFS is proposing to authorize up to 541 takes, by Level B 
harassment, over the 5-year period. No Level A harassment take is 
proposed for authorization. The maximum annual allowable take by Level 
B harassment is 341, which equates to approximately 24 percent of the 
stock abundance, if each take were considered to be of a different 
individual), with far lower numbers than that expected in the years 
without foundation installation (e.g., years when only HRG surveys 
would be occurring). Given that feeding is considered the principal 
activity of humpback whales in southern New England waters, it is 
likely that some subset of the individual whales exposed could be taken 
several times annually.
    Among the activities analyzed, the combination of impact and 
vibratory pile driving has the potential to result in the highest 
amount of annual take of humpback whales (0 takes by Level A harassment 
and 341 takes by Level B harassment) and is of greatest concern, given 
the associated loud source levels associated with impact pile driving 
and large Level B harassment zone resulting from vibratory pile 
driving.
    In the western North Atlantic, humpback whales feed during spring, 
summer, and fall over a geographic range encompassing the eastern coast 
of the U.S. Feeding is generally considered to be focused in areas 
north of the project area, including in a feeding BIA in the Gulf of 
Maine/Stellwagen Bank/Great South Channel, but has been documented off 
the coast of southern New England and as far south as Virginia (Swingle 
et al., 1993). Foraging animals tend to remain in the area for extended 
durations to capitalize on the food sources.
    Assuming humpback whales who are feeding in waters within or 
surrounding the project area behave similarly, we expect that the 
predicted instances of disturbance could consist of some individuals 
that may be exposed on multiple days if they are utilizing the area as 
foraging habitat. Also similar to other baleen whales, if migrating, 
such individuals would likely be exposed to noise levels from the 
project above the harassment thresholds only once during migration 
through the project area.
    For all the reasons described in the Mysticetes section above, we 
anticipate any potential PTS and TTS would be concentrated at half or 
one octave above the frequency band of pile driving noise (most sound 
is below 2 kHz), which does not include the full predicted hearing 
range of baleen whales. If TTS is incurred, hearing sensitivity would 
likely return to pre-exposure levels relatively shortly after exposure 
ends. Any masking or physiological responses would also be of low 
magnitude and severity for reasons described above.
    Given the magnitude and severity of the impacts discussed above 
(including no more than 541 takes over the course of the 5-year rule, 
and a maximum annual allowable take by Level A harassment and Level B 
harassment, of 0 and 341 respectively), and in consideration of the 
required mitigation measures and other information presented, 
SouthCoast's activities are not expected to result in impacts on the 
reproduction or survival of any individuals, much less affect annual 
rates of recruitment or survival. For these reasons, we have 
preliminarily determined that the take by harassment anticipated and 
proposed for authorization will have a negligible impact on the Gulf of 
Maine stock of humpback whales.

Odontocetes

    In this section, we include information here that applies to all of 
the odontocete species and stocks addressed below, which are further 
divided into the following subsections: sperm whales, dolphins and 
small whales; and harbor porpoises. These sub-sections include more 
specific information, as well as conclusions for each stock 
represented.
    The takes of odontocetes proposed for authorization are incidental 
to pile driving, UXO/MEC detonations, and HRG surveys. No serious 
injury or mortality is anticipated or proposed for authorization. We 
anticipate that, given ranges of individuals (i.e., that some 
individuals remain within a small area for some period of time) and 
non-migratory nature of some odontocetes in general (especially as 
compared to mysticetes), a larger subset of these takes are more likely 
to represent multiple exposures of some number of individuals than is 
the case for mysticetes, though some takes may also represent one-time 
exposures to an individual. Foundation installation is likely to 
disturb odontocetes to the greatest extent compared to UXO/MEC 
detonations and HRG surveys. While we expect animals to avoid the area 
during foundation installation and UXO/MEC detonations, their habitat 
range is extensive compared to the area ensonified during these 
activities. In addition, as described above, UXO/MEC detonations are 
instantaneous; therefore, any disturbance would be very limited in 
time.
    Any masking or TTS effects are anticipated to be of low severity. 
First, while the frequency range of pile driving, the most impactful 
planned activity in terms of response severity, falls within a portion 
of the frequency range of most odontocete vocalizations, odontocete 
vocalizations span a much wider range than the low frequency 
construction activities planned for the project. Also, as described 
above, recent studies suggest odontocetes have a mechanism to self-
mitigate the impacts of noise exposure (i.e., reduce hearing 
sensitivity), which could potentially reduce TTS impacts. Any masking 
or TTS is anticipated to be limited and would typically only interfere 
with communication within a portion of an odontocete's range and as 
discussed earlier, the effects would only be expected to be of a short 
duration and for TTS, a relatively small degree.
    Furthermore, odontocete echolocation occurs predominantly at 
frequencies significantly higher than low frequency construction 
activities. Therefore, there is little likelihood that threshold shift 
would interfere with feeding behaviors. The sources operate at higher 
frequencies than foundation installation activities HRG surveys and 
UXO/MEC detonations. However, sounds from these sources attenuate very 
quickly in the water column, as described above. Therefore, any 
potential for PTS and TTS and masking is very limited. Further, 
odontocetes (e.g., common dolphins, spotted dolphins, bottlenose 
dolphins) have demonstrated an affinity to bow-ride actively surveying 
HRG surveys. Therefore, the severity of any harassment, if it does 
occur, is anticipated to be minimal based on the lack of avoidance 
previously demonstrated by these species.
    The waters off the coast of Massachusetts are used by several 
odontocete species; however, none (except the sperm whale) are listed 
under the ESA and there are no known habitats of particular importance. 
In general, odontocete habitat ranges are far-reaching along the 
Atlantic coast of the U.S., and the waters off of New England, 
including the project area, do not contain any particularly unique 
odontocete habitat features.
Sperm Whale
    The Western North Atlantic stock of sperm whales spans the East 
Coast out into oceanic waters well beyond the U.S. EEZ. Although listed 
as endangered, the primary threat faced by

[[Page 53807]]

the sperm whale (i.e., commercial whaling) has been eliminated and, 
further, sperm whales in the western North Atlantic were little 
affected by modern whaling (Taylor et al., 2008). Current potential 
threats to the species globally include vessel strikes, entanglement in 
fishing gear, anthropogenic noise, exposure to contaminants, climate 
change, and marine debris. There is no currently reported trend for the 
stock and, although the species is listed as endangered under the ESA, 
there are no specific issues with the status of the stock that cause 
particular concern (e.g., no UMEs). There are no known areas of 
biological importance (e.g., critical habitat or BIAs) in or near the 
project area.
    No mortality, serious injury or Level A harassment is anticipated 
or proposed for authorization for this species. Impacts would be 
limited to Level B harassment and would occur to only a small number of 
individuals (maximum of 126 in any given year (likely year 2) and 149 
across all 5 years) incidental to pile driving, UXO/MEC detonation(s), 
and HRG surveys. Sperm whales are not common within the project area 
due to the shallow waters, and it is not expected that any noise levels 
would reach habitat in which sperm whales are common, including deep-
water foraging habitat. If sperm whales do happen to be present in the 
project area during any activities related to the SouthCoast project, 
they would likely be only transient visitors and not engaging in any 
significant behaviors. This very low magnitude and severity of effects 
is not expected to result in impacts on the reproduction or survival of 
individuals, much less impact annual rates of recruitment or survival. 
For these reasons, we have preliminarily determined, in consideration 
of all of the effects of the SouthCoast's activities combined, that the 
take proposed for authorization would have a negligible impact on the 
North Atlantic stock of sperm whales.
Dolphins and Small Whales (Including Delphinids and Pilot Whales)
    There are no specific issues with the status of odontocete stocks 
that cause particular concern (e.g., no recent UMEs). No mortality or 
serious injury is expected or proposed for authorization for these 
stocks. No Level A harassment is anticipated or proposed for 
authorization for any dolphin or small whale.
    The maximum number of take, by Level B harassment, proposed for 
authorization within any one year for all odontocetes cetacean stocks 
ranges from 522 to 52,943 instances, which is less than approximately 5 
percent for 5 stocks and less that 25 percent for one stock, as 
compared to the population size for all stocks. The common dolphin, one 
of the most frequently occurring marine mammals in southern New 
England, is the species for which take estimation resulted in the 
maximum number of takes (n=52,943) and associated population percentage 
(24.5 percent) among small odontocetes. As described above for 
odontocetes broadly, we anticipate that a fair number of these 
instances of take in a day represent multiple exposures of a smaller 
number of individuals, meaning the actual number of individuals taken 
is lower. Although some amount of repeated exposure to some individuals 
is likely given the duration of activity proposed by SouthCoast, the 
intensity of any Level B harassment combined with the availability of 
alternate nearby foraging habitat suggests that the likely impacts 
would not impact the reproduction or survival of any individuals.
    Overall, the populations of all dolphins and small whale species 
and stocks for which we propose to authorize take are stable (no 
declining population trends), not facing existing UMEs, and the small 
number, magnitude and severity of takes is not expected to result in 
impacts on the reproduction or survival of any individuals, much less 
affect annual rates of recruitment or survival. For these reasons, we 
have preliminarily determined, in consideration of all of the effects 
of the SouthCoast's activities combined, that the take proposed for 
authorization would have a negligible impact on all dolphin and small 
whale species and stocks considered in this analysis.
Harbor Porpoises
    The Gulf of Maine/Bay of Fundy stock of harbor porpoises is found 
predominantly in northern U.S. coastal waters (less than 150 m depth) 
and up into Canada's Bay of Fundy. Although the population trend is not 
known, there are no UMEs or other factors that cause particular concern 
for this stock. No mortality or non-auditory injury is anticipated or 
proposed for authorization for this stock. NMFS proposes to authorize 
109 takes by Level A harassment (PTS; incidental to UXO/MEC 
detonations) and 3,442 takes by Level B harassment (incidental to 
multiple activities).
    Regarding the severity of takes by behavioral Level B harassment, 
because harbor porpoises are particularly sensitive to noise, it is 
likely that a fair number of the responses could be of a moderate 
nature, particularly to pile driving. In response to pile driving, 
harbor porpoises are likely to avoid the area during construction, as 
previously demonstrated in Tougaard et al. (2009) in Denmark, in Dahne 
et al. (2013) in Germany, and in Vallejo et al. (2017) in the United 
Kingdom, although a study by Graham et al. (2019) may indicate that the 
avoidance distance could decrease over time. However, pile driving is 
scheduled to occur when harbor porpoise abundance is low off the coast 
of Massachusetts and, given alternative foraging areas, any avoidance 
of the area by individuals is not likely to impact the reproduction or 
survival of any individuals. Given only one UXO/MEC would be detonated 
on any given day and up to only 10 UXO/MEC would be detonated over the 
5-year effective period of the LOA, any behavioral response would be 
brief and of a low severity.
    With respect to PTS and TTS, the effects on an individual are 
likely relatively low given the frequency bands of pile driving (most 
energy below 2 kHz) compared to harbor porpoise hearing (150 Hz to 160 
kHz peaking around 40 kHz). Specifically, PTS or TTS is unlikely to 
impact hearing ability in their more sensitive hearing ranges, or the 
frequencies in which they communicate and echolocate. Regardless, we 
have authorized a limited amount of PTS, but expect any PTS that may 
occur to be within the very low end of their hearing range where harbor 
porpoises are not particularly sensitive, and any PTS would be of small 
magnitude. As such, any PTS would not interfere with key foraging or 
reproductive strategies necessary for reproduction or survival.
    In summary, the number of takes proposed for authorization across 
all 5 years is 109 by Level A harassment and 3,442 by Level B 
harassment. While harbor porpoises are likely to avoid the area during 
any construction activity discussed herein, as demonstrated during 
European wind farm construction, the time of year in which work would 
occur is when harbor porpoises are not in high abundance, and any work 
that does occur would not result in the species' abandonment of the 
waters off of Massachusetts. The low magnitude and severity of 
harassment effects is not expected to result in impacts on the 
reproduction or survival of any individuals, let alone have impacts on 
annual rates of recruitment or survival of this stock. No mortality or 
serious injury is anticipated or proposed for authorization. For these 
reasons, we have preliminarily determined, in

[[Page 53808]]

consideration of all of the effects of the SouthCoast's activities 
combined, that the proposed authorized take would have a negligible 
impact on the Gulf of Maine/Bay of Fundy stock of harbor porpoises.

Phocids (Harbor Seals and Gray Seals)

    Neither the harbor seal nor gray seal are listed under the ESA. 
SouthCoast requested, and NMFS proposes to authorize, that no more than 
4 and 677 harbor seals and 40 and 9,835 gray seals may be taken by 
Level A harassment and Level B harassment, respectively, within any one 
year. These species occur in Massachusetts waters most often in winter, 
when impact pile driving and UXO/MEC detonations would not occur. Seals 
are also more likely to be close to shore such that exposure to impact 
pile driving would be expected to be at lower levels generally (but 
still above NMFS behavioral harassment threshold). The majority of 
takes of these species is from monopile installations, and HRG surveys. 
Research and observations show that pinnipeds in the water may be 
tolerant of anthropogenic noise and activity (a review of behavioral 
reactions by pinnipeds to impulsive and non-impulsive noise can be 
found in Richardson et al. (1995) and Southall et al. (2007)). 
Available data, though limited, suggest that exposures between 
approximately 90 and 140 dB SPL do not appear to induce strong 
behavioral responses in pinnipeds exposed to non-pulse sounds in water 
(Costa et al., 2003; Jacobs and Terhune, 2002; Kastelein et al., 
2006c). Although there was no significant displacement during 
construction as a whole, Russell et al. (2016) found that displacement 
did occur during active pile driving at predicted received levels 
between 168 and 178 dB re 1[micro]Pa(p-p); however seal 
distribution returned to the pre-piling condition within two hours of 
cessation of pile driving. Pinnipeds may not react at all until the 
sound source is approaching (or they approach the sound source) within 
a few hundred meters and then may alert, ignore the stimulus, change 
their behaviors, or avoid the immediate area by swimming away or 
diving. Effects on pinnipeds that are taken by Level B harassment in 
the project area would likely be limited to reactions such as increased 
swimming speeds, increased surfacing time, or decreased foraging (if 
such activity were occurring). Most likely, individuals would simply 
move away from the sound source and be temporarily displaced from those 
areas (see Lucke et al., 2006; Edren et al., 2010; Skeate et al., 2012; 
Russell et al., 2016). Given their documented tolerance of 
anthropogenic sound (Richardson et al., 1995; Southall et al., 2007), 
repeated exposures of individuals of either of these species to levels 
of sound that may cause Level B harassment are unlikely to 
significantly disrupt foraging behavior. Given the low anticipated 
magnitude of impacts from any given exposure, even repeated Level B 
harassment across a few days of some small subset of individuals, which 
could occur, is unlikely to result in impacts on the reproduction or 
survival of any individuals. Moreover, pinnipeds would benefit from the 
mitigation measures described in the Proposed Mitigation section.
    SouthCoast requested, and NMFS is proposing to authorize, a limited 
number of takes by Level A harassment in the form of PTS (4 harbor 
seals and 40 gray seals) incidental to UXO/MEC detonations over the 5-
year effective period of the rule. As described above, noise from UXO/
MEC detonation is low frequency and while any PTS that does occur would 
fall within the lower end of pinniped hearing ranges (50 Hz to 86 kHz), 
PTS would not occur at frequencies where pinniped hearing is most 
sensitive. In summary, any PTS, would be of limited degree and not 
occur across the entire or even most sensitive hearing range. Hence, 
any impacts from PTS are likely to be of low severity and not interfere 
with behaviors critical to reproduction or survival.
    Elevated numbers of harbor seal and gray seal mortalities were 
first observed in July 2018 and occurred across Maine, New Hampshire, 
and Massachusetts until 2020. Based on tests conducted so far, the main 
pathogen found in the seals belonging to that UME was phocine distemper 
virus, although additional testing to identify other factors that may 
be involved in this UME are underway. In 2022, a UME was declared in 
Maine with some harbor and gray seals testing positive for highly 
pathogenic avian influenza (HPAI) H5N1. Although elevated strandings 
continue. For harbor seals, the population abundance is over 75,000 and 
annual M/SI (350) is well below PBR (2,006) (Hayes et al., 2020). The 
population abundance for gray seals in the United States is over 
27,000, with an estimated overall abundance, including seals in Canada, 
of approximately 450,000. In addition, the abundance of gray seals is 
likely increasing in the U.S. Atlantic, as well as in Canada (Hayes et 
al., 2020).
    Overall, impacts from the Level B harassment take proposed for 
authorization incidental to SouthCoast's specified activities would be 
of relatively low magnitude and a low severity. Similarly, while some 
individuals may incur PTS overlapping some frequencies that are used 
for foraging and communication, given the low degree, the impacts would 
not be expected to impact reproduction or survival of any individuals. 
In consideration of all of the effects of SouthCoast's activities 
combined, we have preliminarily determined that the authorized take 
will have a negligible impact on harbor seals and gray seals.

Preliminary Negligible Impact Determination

    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat and taking into 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the proposed marine 
mammal take from all of SouthCoast 's specified activities combined 
will have a negligible impact on all affected marine mammal species or 
stocks.

Small Numbers

    As noted above, only small numbers of incidental take may be 
authorized under sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals 
estimated to be taken to the most appropriate estimation of abundance 
of the relevant species or stock in our determination of whether an 
authorization is limited to small numbers of marine mammals. When the 
predicted number of individuals to be taken is less than one-third of 
the species or stock abundance, the take is considered to be of small 
numbers. Additionally, other qualitative factors may be considered in 
the analysis, such as the temporal or spatial scale of the activities.
    NMFS proposes to authorize incidental take (by Level A harassment 
and Level B harassment) of 16 species of marine mammal (with 16 managed 
stocks). The maximum number of takes possible within any one year and 
proposed for authorization relative to the best available population 
abundance is less than one-third for all species and stocks potentially 
impacted (i.e., less than 1 percent for 5 stocks, less than 8 percent 
for 7 stocks, less than 25 percent for 2 stocks, and less than 33 
percent for 2 stocks; see table 53).
    Based on the analysis contained herein of the proposed activities 
(including the proposed mitigation and

[[Page 53809]]

monitoring measures) and the anticipated take of marine mammals, NMFS 
preliminarily finds that small numbers of marine mammals would be taken 
relative to the population size of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

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

Classification

Endangered Species Act (ESA)

    Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16 
U.S.C. 1531 et seq.) requires that each Federal agency ensure that any 
action it authorizes, funds, or carries out is not likely to jeopardize 
the continued existence of any endangered or threatened species or 
result in the destruction or adverse modification of designated 
critical habitat. To ensure ESA compliance for the promulgation of 
rulemakings, NMFS consults internally whenever we propose to authorize 
take for endangered or threatened species, in this case with the NMFS 
Greater Atlantic Regional Field Office (GARFO).
    NMFS is proposing to authorize the take of five marine mammal 
species which are listed under the ESA: the North Atlantic right, sei, 
fin, blue, and sperm whale. The Permit and Conservation Division 
requested initiation of Section 7 consultation on November 1, 2022 with 
GARFO for the promulgation of this proposed rulemaking. NMFS will 
conclude the Endangered Species Act consultation prior to reaching a 
determination regarding the proposed issuance of the authorization. The 
proposed regulations and any subsequent LOA(s) would be conditioned 
such that, in addition to measures included in those documents, 
SouthCoast would also be required to abide by the reasonable and 
prudent measures and terms and conditions of a Biological Opinion and 
Incidental Take Statement, issued by NMFS, pursuant to Section 7 of the 
Endangered Species Act.

Executive Order 12866

    The Office of Management and Budget has determined that this 
proposed rule is not significant for purposes of Executive Order 12866.

Regulatory Flexibility Act (RFA)

    Pursuant to the RFA (5 U.S.C. 601 et seq.), the Chief Counsel for 
Regulation of the Department of Commerce has certified to the Chief 
Counsel for Advocacy of the Small Business Administration that this 
proposed rule, if adopted, would not have a significant economic impact 
on a substantial number of small entities. SouthCoast is the sole 
entity that would be subject to the requirements in these proposed 
regulations, and SouthCoast is not a small governmental jurisdiction, 
small organization, or small business, as defined by the RFA. Because 
of this certification, a regulatory flexibility analysis is not 
required and none has been prepared.

Paperwork Reduction Act (PRA)

    Notwithstanding any other provision of law, no person is required 
to respond to nor shall a person be subject to a penalty for failure to 
comply with a collection of information subject to the requirements of 
the PRA unless that collection of information displays a currently 
valid Office of Management and Budget (OMB) control number. These 
requirements have been approved by OMB under control number 0648-0151 
and include applications for regulations, subsequent LOA, and reports. 
Submit comments regarding any aspect of this data collection, including 
suggestions for reducing the burden, to NMFS.

Coastal Zone Management Act (CZMA)

    We have preliminarily determined that this action is not within or 
would not affect a state's coastal zone, and thus do not require a 
consistency determination under 307(c)(3)(A) of the Coastal Zone 
Management Act (CZMA; 16 U.S.C. 1456 (c)(3)(A)). Since the proposed 
action is expected to authorize incidental take of marine mammals in 
coastal waters and on the outer continental shelf, and is an unlisted 
activity under 15 CFR 930.54, the only way in which this action would 
be subject to state consistency review is if the state timely submits 
an unlisted activity request to the Director of NOAA's Office for 
Coastal Management (along with copies concurrently submitted to the 
applicant and NMFS) within 30 days from the date of publication of the 
notice of proposed rulemaking in the Federal Register and the Director 
approves such request.

Proposed Promulgation

    As a result of these preliminary determinations, NMFS proposes to 
promulgate regulations that allow for the authorization of take, by 
Level A harassment and Level B harassment, incidental to construction 
activities associated with the SouthCoast Wind Project offshore of 
Massachusetts for a 5-year period from April 1, 2027, through March 31, 
2032, provided the previously mentioned mitigation, monitoring, and 
reporting requirements are incorporated.

Request for Additional Information and Public Comments

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

List of Subjects in 50 CFR Part 217

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

    Dated: June 17, 2024.
Samuel D. Rauch III,
Deputy Assistant Administrator for Regulatory Programs, National Marine 
Fisheries Service.
    For reasons set forth in the preamble, NMFS proposes to amend 50 
CFR part 217 as follows:

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

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

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

0
2. Add subpart HH, consisting of Sec. Sec.  217.330 through 217.339, to 
read as follows:
Subpart HH--Taking Marine Mammals Incidental to the SouthCoast Wind 
Offshore Wind Farm Project Offshore Massachusetts
Sec.

[[Page 53810]]

217.330 Specified activity and specified geographical region.
217.331 Effective dates.
217.332 Permissible methods of taking.
217.333 Prohibitions.
217.334 Mitigation requirements.
217.335 Requirements for monitoring and reporting.
217.336 Letter of Authorization.
217.337 Modifications of Letter of Authorization.
217.338-217.339 [Reserved]

Subpart HH--Taking Marine Mammals Incidental to the SouthCoast Wind 
Project Offshore Massachusetts


Sec.  217.330  Specified activity and specified geographical region.

    (a) Regulations in this subpart apply only to activities associated 
with the SouthCoast Wind Project conducted by SouthCoast Wind Energy, 
LLC (SouthCoast Wind) and those persons SouthCoast Wind authorizes or 
funds to conduct activities on its behalf in the area outlined in 
paragraph (b) of this section. Requirements imposed on SouthCoast Wind 
must be implemented by those persons it authorizes or funds to conduct 
activities on its behalf.
    (b) The specified geographical region is the Mid-Atlantic Bight and 
vessel transit routes to marshaling ports in Charleston, South Carolina 
and Sheet Harbor, Canada. The Mid-Atlantic Bight extends between Cape 
Hatteras, North Carolina and Martha's Vineyard, Massachusetts, 
extending westward into the Atlantic to the 100-m isobath and includes, 
but is not limited to, the Bureau of Ocean Energy Management (BOEM) 
Lease Area Outer Continental Shelf (OCS)-A-0521 Commercial Lease of 
Submerged Lands for Renewable Energy Development, two export cable 
routes, and two sea-to-shore transition point at Brayton Point in 
Somerset, Massachusetts and Falmouth, Massachusetts.
    (c) The specified activities are impact and vibratory pile driving 
to install wind turbine generator (WTG) and offshore substation 
platform (OSP) foundations; high-resolution geophysical (HRG) site 
characterization surveys; detonation of unexploded ordnances or 
munitions and explosives of concern (UXOs/MECs); fisheries and benthic 
monitoring surveys; placement of scour protection; sand leveling; 
dredging; trenching, laying, and burial activities associated with the 
installation of the export cable from the OSP to shore based converter 
stations and inter-array cables between WTG foundations; vessel transit 
within the specified geographical region to transport crew, supplies, 
and materials; and WTG operations.


Sec.  217.331  Effective dates.

    The regulations in this subpart are effective from April 1, 2027 
through March 31, 2032.


Sec.  217.332  Permissible methods of taking.

    Under a LOA issued pursuant to Sec. Sec.  216.106 and 217.336, 
SouthCoast Wind and those persons it authorizes or funds to conduct 
activities on its behalf, may incidentally, but not intentionally, take 
marine mammals within the specified geographicalregion in the following 
ways, provided SouthCoast Wind is in compliance with all terms, 
conditions, and requirements of the regulations in this subpart and the 
LOA.
    (a) By Level B harassment associated with the acoustic disturbance 
of marine mammals by impact and vibratory pile driving of WTG and OSP 
foundations; UXO/MEC detonations, and HRG site characterization 
surveys.
    (b) By Level A harassment associated with impact pile driving WTG 
and OSP foundations and UXO/MEC detonations.
    (c) The incidental take of marine mammals by the activities listed 
in paragraphs (a) and (b) of this section is limited to the following 
species and stocks:

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

Sec.  217.333  Prohibitions.

    Except for the takings described in Sec.  217.332 and authorized by 
a LOA issued under Sec. Sec.  217.336 or 217.337, it is unlawful for 
any person to do any of the following in connection with the activities 
described in this subpart.
    (a) Violate or fail to comply with the terms, conditions, and 
requirements of this subpart or a LOA issued under Sec. Sec.  217.336 
or 217.337.
    (b) Take any marine mammal not specified in Sec.  217.332(c).
    (c) Take any marine mammal specified in Sec.  217.332(c) in any 
manner other than specified in Sec.  217.332(a) and (b).


Sec.  217.334  Mitigation requirements.

    When conducting the specified activities identified in Sec. Sec.  
217.330(c), SouthCoast Wind must implement the following mitigation 
measures contained in this section and any LOA issued under Sec. Sec.  
217.336 or 217.337 of this subpart. These mitigation measures include, 
but are not limited to:
    (a) General Conditions. SouthCoast Wind must comply with the 
following general measures:
    (1) A copy of any issued LOA must be in the possession of 
SouthCoast Wind and its designees, all vessel operators, visual 
protected species observers (PSOs), passive acoustic monitoring (PAM) 
operators, pile driver operators, and any other relevant designees 
operating under the authority of the

[[Page 53811]]

issued LOA; (2) SouthCoast Wind must conduct training for construction 
supervisors, construction crews, and the PSO and PAM team prior to the 
start of all construction activities and when new personnel join the 
work in order to explain responsibilities, communication procedures, 
marine mammal monitoring and reporting protocols, and operational 
procedures. A description of the training program must be provided to 
NMFS at least 60 days prior to the initial training before in-water 
activities begin. Confirmation of all required training must be 
documented on a training course log sheet and reported to NMFS Office 
of Protected Resources prior to initiating project activities;
    (3) SouthCoast Wind is required to use available sources of 
information on North Atlantic right whale presence to aid in monitoring 
efforts. These include daily monitoring of the Right Whale Sighting 
Advisory System, consulting of the WhaleAlert app, and monitoring of 
the Coast Guard's VHF Channel 16 to receive notifications of marine 
mammal sightings and information associated with any Dynamic Management 
Areas (DMA) and Slow Zones;
    (4) Any marine mammal observation by project personnel must be 
immediately communicated to any on-duty PSOs and PAM operator(s). Any 
large whale observation or acoustic detection by any project personnel 
must be conveyed to all vessel captains;
    (5) If an individual from a species for which authorization has not 
been granted or a species for which authorization has been granted but 
the authorized take number has been met is observed entering or within 
the relevant clearance zone prior to beginning a specified activity, 
the activity must be delayed. If an activity is ongoing and an 
individual from a species for which authorization has not been granted 
or a species for which authorization has been granted but the 
authorized take number has been met is observed entering or within the 
relevant shutdown zone, the activity must be shut down (i.e., cease) 
immediately unless shutdown would result in imminent risk of injury or 
loss of life to an individual, pile refusal, or pile instability. The 
activity must not commence or resume until the animal(s) has been 
confirmed to have left the clearance or shutdown zones and is on a path 
away from the applicable zone or after 30 minutes for all baleen whale 
species and sperm whales, and 15 minutes for all other species;
    (6) In the event that a large whale is sighted or acoustically 
detected that cannot be confirmed as a non-North Atlantic right whale, 
it must be treated as if it were a North Atlantic right whale for 
purposes of mitigation;
    (7) For in-water construction heavy machinery activities listed in 
section 1(a), if a marine mammal is detected within or about to enter 
10 meters (m) (32.8 feet (ft)) of equipment, SouthCoast Wind must cease 
operations until the marine mammal has moved more than 10 m on a path 
away from the activity to avoid direct interaction with equipment;
    (8) All vessels must be equipped with a properly installed, 
operational Automatic Identification System (AIS) device prior to 
vessel use and SouthCoast Wind must report all Maritime Mobile Service 
Identify (MMSI) numbers to NMFS Office of Protected Resources;
    (9) By accepting a LOA, SouthCoast Wind consents to on-site 
observation and inspections by Federal agency personnel (including NOAA 
personnel) during activities described in this subpart, for the 
purposes of evaluating the implementation and effectiveness of measures 
contained within this subpart and the LOA; and
    (10) It is prohibited to assault, harm, harass (including sexually 
harass), oppose, impede, intimidate, impair, or in any way influence or 
interfere with a PSO, PAM operator, or vessel crew member acting as an 
observer, or attempt the same. This prohibition includes, but is not 
limited to, any action that interferes with an observer's 
responsibilities or that creates an intimidating, hostile, or offensive 
environment. Personnel may report any violations to the NMFS Office of 
Law Enforcement.
    (b) Vessel strike avoidance measures: SouthCoast Wind must comply 
with the following vessel strike avoidance measures while in the 
specific geographic region unless a deviation is necessary to maintain 
safe maneuvering speed and justified because the vessel is in an area 
where oceanographic, hydrographic, and/or meteorological conditions 
severely restrict the maneuverability of the vessel; an emergency 
situation presents a threat to the health, safety, life of a person; or 
when a vessel is actively engaged in emergency rescue or response 
duties, including vessel-in distress or environmental crisis response. 
An emergency is defined as a serious event that occurs without warning 
and requires immediate action to avert, control, or remedy harm.
    (1) Prior to the start of the Project's activities involving 
vessels, all vessel personnel must receive a protected species training 
that covers, at a minimum, identification of marine mammals that have 
the potential to occur in the specified geographical region; detection 
and observation methods in both good weather conditions (i.e., clear 
visibility, low winds, low sea states) and bad weather conditions 
(i.e., fog, high winds, high sea states, with glare); sighting 
communication protocols; all vessel strike avoidance mitigation 
requirements; and information and resources available to the project 
personnel regarding the applicability of Federal laws and regulations 
for protected species. This training must be repeated for any new 
vessel personnel who join the project. Confirmation of the vessel 
personnels' training and understanding of the LOA requirements must be 
documented on a training course log sheet and reported to NMFS within 
30 days of completion of training, prior to personnel joining vessel 
operations;
    (2) All vessel operators and dedicated visual observers must 
maintain a vigilant watch for all marine mammals and slow down, stop 
their vessel, or alter course to avoid striking any marine mammal;
    (3) All transiting vessels, operating at any speed must have a 
dedicated visual observer on duty at all times to monitor for marine 
mammals within a 180 degrees ([deg]) direction of the forward path of 
the vessel (90[deg] port to 90[deg] starboard) located at an 
appropriate vantage point for ensuring vessels are maintaining required 
separation distances. Dedicated visual observers may be PSOs or crew 
members, but crew members responsible for these duties must be provided 
sufficient training by SouthCoast Wind to distinguish marine mammals 
from other phenomena and must be able to identify a marine mammal as a 
North Atlantic right whale, other large whale (defined in this context 
as sperm whales or baleen whales other than North Atlantic right 
whales), or other marine mammals. Dedicated visual observers must be 
equipped with alternative monitoring technology (e.g., night vision 
devices, infrared cameras) for periods of low visibility (e.g., 
darkness, rain, fog, etc.). The dedicated visual observer must not have 
any other duties while observing and must receive prior training on 
protected species detection and identification, vessel strike avoidance 
procedures, how and when to communicate with the vessel captain, and 
reporting requirements in this subpart;
    (4) All vessel operators and dedicated visual observers must 
continuously monitor US Coast Guard VHF Channel 16 at the onset of 
transiting through the

[[Page 53812]]

duration of transit. At the onset of transiting and at least once every 
4 hours, vessel operators and/or trained crew member(s) must also 
monitor the project's Situational Awareness System, (if applicable), 
WhaleAlert, and relevant NOAA information systems such as the Right 
Whale Sighting Advisory System (RWSAS) for the presence of North 
Atlantic right whales;
    (5) Prior to transit, vessel operators must check for information 
regarding the establishment of Seasonal and Dynamic Management Areas, 
Slow Zones, and any information regarding North Atlantic right whale 
sighting locations;
    (6) All vessel operators must abide by vessel speed regulations (50 
CFR 224.105). Nothing in this subpart exempts vessels from any other 
applicable marine mammal speed or approach regulations;
    (7) All vessels, regardless of size, must immediately reduce speed 
to 10 knots (18.5 km/hr) or less for at least 24 hours when a North 
Atlantic right whale is sighted at any distance by any project related 
personnel or acoustically detected by any project-related PAM system. 
Each subsequent observation or acoustic detection in the Project area 
must trigger an additional 24-hour period. If a North Atlantic right 
whale is reported via any of the monitoring systems (described in 
paragraph (b)(4) of this section) within 10 km of a transiting 
vessel(s), that vessel must operate at 10 knots (18.5 km/hr) or less 
for 24 hours following the reported detection.
    (8) In the event that a DMA or Slow Zone is established that 
overlaps with an area where a project-associated vessel is operating, 
that vessel, regardless of size, must transit that area at 10 knots 
(18.5 km/hr) or less;
    (9) Between November 1st and April 30th, all vessels, regardless of 
size, must operate at 10 knots (18.5 km/hr) or less in the specified 
geographical region, except for vessels while transiting in 
Narragansett Bay or Long Island Sound;
    (10) All vessels, regardless of size, must immediately reduce speed 
to 10 knots (18.5 km/hr) or less when any large whale, (other than a 
North Atlantic right whale), mother/calf pairs, or large assemblages of 
non-delphinid cetaceans are observed within 500 m (0.31 mi) of a 
transiting vessel;
    (11) If a vessel is traveling at any speed greater than 10 knots 
(18.5 km/hr) (i.e., no speed restrictions are enacted) in the transit 
corridor (defined as from a port to the Lease Area or return), in 
addition to the required dedicated visual observer, SouthCoast Wind 
must monitor the transit corridor in real-time with PAM prior to and 
during transits. If a North Atlantic right whale is detected via visual 
observation or PAM within or approaching the transit corridor, all 
vessels in the transit corridor must travel at 10 knots (18.5 km/hr) or 
less for 24 hours following the detection. Each subsequent detection 
shall trigger a 24-hour reset. A slowdown in the transit corridor 
expires when there has been no further North Atlantic right whale 
visual or acoustic detection in the transit corridor in the past 24 
hours;
    (12) All vessels must maintain a minimum separation distance of 500 
m from North Atlantic right whales. If underway, all vessels must steer 
a course away from any sighted North Atlantic right whale at 10 knots 
(18.5 km/hr) or less such that the 500-m minimum separation distance 
requirement is not violated. If a North Atlantic right whale is sighted 
within 500 m of an underway vessel, that vessel must turn away from the 
whale(s), reduce speed and shift the engine to neutral. Engines must 
not be engaged until the whale has moved outside of the vessel's path 
and beyond 500 m;
    (13) All vessels must maintain a minimum separation distance of 100 
m (328 ft) from sperm whales and non-North Atlantic right whale baleen 
whales. If one of these species is sighted within 100 m (328 ft) of an 
underway vessel, the vessel must turn away from the whale(s), reduce 
speed, and shift the engine(s) to neutral. Engines must not be engaged 
until the whale has moved outside of the vessel's path and beyond 100 m 
(328 ft);
    (14) All vessels must maintain a minimum separation distance of 50 
m (164 ft) from all delphinid cetaceans and pinnipeds with an exception 
made for those that approach the vessel (e.g., bow-riding dolphins). If 
a delphinid cetacean or pinniped is sighted within 50 m (164 ft) of a 
transiting vessel, that vessel must turn away from the animal(s), 
reduce speed, and shift the engine to neutral, with an exception made 
for those that approach the vessel (e.g., bow-riding dolphins). Engines 
must not be engaged until the animal(s) has moved outside of the 
vessel's path and beyond 50 m (164 ft);
    (15) All vessels underway must not divert or alter course to 
approach any marine mammal; and
    (16) SouthCoast Wind must submit a Marine Mammal Vessel Strike 
Avoidance Plan 180 days prior to the planned start of vessel activity 
that provides details on all relevant mitigation and monitoring 
measures for marine mammals, vessel speeds and transit protocols from 
all planned ports, vessel-based observer protocols for transiting 
vessels, communication and reporting plans, and proposed alternative 
monitoring equipment in varying weather conditions, darkness, sea 
states, and in consideration of the use of artificial lighting. If 
SouthCoast Wind plans to implement PAM in any transit corridor to allow 
vessel transit above 10 knots (18.5 km/hr) the plan must describe how 
PAM, in combination with visual observations, will be conducted. If a 
plan is not submitted and approved by NMFS prior to vessel operations, 
all project vessels must travel at speeds of 10 knots (18.5 km/hr) or 
less. SouthCoast Wind must comply with any approved Marine Mammal 
Vessel Strike Avoidance Plan.
    (c) Wind turbine generator (WTG) and offshore substation platform 
(OSP) foundation installation. The following requirements apply to 
vibratory and impact pile driving activities associated with the 
installation of WTG and OSP foundations: (1) Foundation pile driving 
activities must not occur January 1 through May 15 throughout the Lease 
Area. From October 16 through May 31, impact and vibratory pile driving 
must not occur at locations in SouthCoast's Lease Area within the North 
Atlantic right whale Enhanced Mitigation Area (NARW EMA; defined as the 
area within 20 km (12.4 mi) from the 30-m (98-ft) isobath on the west 
side of Nantucket Shoals);
    (2) Outside of the NARW EMA, foundation pile driving must not be 
planned for December; however, it may occur only if necessary to 
complete pile driving within a given year and with prior approval by 
NMFS and implementation of enhanced mitigation and monitoring (see 
217.334(c)(7), 217.334(c)(13)). SouthCoast Wind must notify NMFS in 
writing by September 1 of that year if circumstances are expected to 
necessitate pile driving in December;
    (3) In the NARW EMA, SouthCoast must install foundations as quickly 
as possible and sequence them from the northeast corner of the Lease 
Area to the southwest corner such that foundation installation in 
positions closest to Nantucket Shoals are completed during the period 
of lowest North Atlantic right whale occurrence in that area;
    (4) Monopiles must be no larger than a tapered 9/16-m diameter 
monopile design and pin piles must be no larger than 4.5-m diameter 
design. The minimum amount of hammer energy necessary to effectively 
and safely install and maintain the integrity of the piles must be 
used. Impact hammer energies must not exceed 6,600

[[Page 53813]]

kilojoules (kJ) for monopile installations and 3,500 kJ for pin pile 
installations;
    (5) SouthCoast must not initiate pile driving earlier than 1 hour 
after civil sunrise or later than 1.5 hours prior to civil sunset 
unless SouthCoast submits and NMFS approves a Nighttime Pile Driving 
Monitoring Plan that demonstrates the efficacy of their low-visibility 
visual monitoring technology (e.g., night vision devices, Infrared (IR) 
cameras) to effectively monitor the mitigation zones in low visibility 
conditions. SouthCoast must submit this plan or plans (if separate 
Daytime Reduced Visibility and Nighttime Monitoring Plans are prepared) 
at least 180 calendar days before foundation installation is planned to 
begin. SouthCoast must submit a separate Plan describing daytime 
reduced visibility monitoring if the information in the Nighttime 
Monitoring Plan does not sufficiently apply to all low-visibility 
monitoring;
    (6) SouthCoast Wind must utilize a soft-start protocol at the 
beginning of foundation installation for each impact pile driving event 
and at any time following a cessation of impact pile driving for 30 
minutes or longer;
    (7) SouthCoast Wind must deploy, at minimum, a double bubble 
curtain during all foundation pile driving;
    (i) The double bubble curtain must distribute air bubbles using an 
air flow rate of at least 0.5 m\3\/(min*m). The double bubble curtain 
must surround 100 percent of the piling perimeter throughout the full 
depth of the water column. In the unforeseen event of a single 
compressor malfunction, the offshore personnel operating the bubble 
curtain(s) must make adjustments to the air supply and operating 
pressure such that the maximum possible sound attenuation performance 
of the bubble curtain(s) is achieved;
    (ii) The lowest bubble ring must be in contact with the seafloor 
for the full circumference of the ring, and the weights attached to the 
bottom ring must ensure 100-percent seafloor contact.
    (iii) No parts of the ring or other objects may prevent full 
seafloor contact with a bubble curtain ring.
    (iv) SouthCoast Wind must inspect and carry out maintenance on the 
noise attenuation systems prior to every pile driving event and prepare 
and submit a Noise Attenuation System (NAS) inspection/performance 
report. For piles for which Thorough SFV (T-SFV) (as required by 
217.334(c)(19)) is carried out, this report must be submitted as soon 
as it is available, but no later than when the interim T-SFV report is 
submitted for the respective pile. Performance reports for all 
subsequent piles must be submitted with the weekly pile driving 
reports. All reports must be submitted by email to 
[email protected].
    (8) SouthCoast Wind must utilize PSOs. Each monitoring platform 
must have at least three on-duty PSOs. PSOs must be located on the pile 
driving vessel as well as on a minimum of three PSO-dedicated vessels 
inside the NARW EMA June 1 through July 31 and outside the NARW EMA 
June 1 through November 30, and a minimum of four PSO-dedicated vessels 
within the NARW EMA from August 1 through October 15 and throughout the 
Lease Area from May 16-31 and December 1-31 (if pile driving in 
December is deemed necessary and approved by NMFS);
    (9) Concurrent with visual monitoring, SouthCoast Wind must utilize 
PAM operator(s), as described in a NMFS-approved PAM Plan, who must 
conduct acoustic monitoring of marine mammals for 60 minutes before, 
during, and 30 minutes after completion of impact and vibratory pile 
driving for each pile. PAM operators must immediately communicate all 
detections of marine mammals to the Lead PSO, including any 
determination regarding species identification, distance, and bearing 
and the degree of confidence in the determination;
    (10) To increase situational awareness prior to pile driving, the 
PAM operator must review PAM data collected within the 24 hours prior 
to a pile installation;
    (11) The PAM system must be able to detect marine mammal 
vocalizations, maximize baleen whale detections, and detect North 
Atlantic right whale vocalizations up to a distance of 10 km (6.2 mi) 
and 15 km (9.3mi) during pin pile and monopile installation, 
respectively. NMFS recognizes that detectability of each species' 
vocalizations will vary based on vocalization characteristics (e.g., 
frequency content, source level), acoustic propagation conditions, and 
competing noise sources), such that other marine mammal species (e.g., 
harbor porpoise) may not be detected at 10 km (6.2 mi) or 15 km (9.3 
mi);
    (12) SouthCoast Wind must submit a Passive Acoustic Monitoring Plan 
(PAM Plan) to NMFS Office of Protected Resources for review and 
approval at least 180 days prior to the planned start of foundation 
installation activities and abide by the Plan if approved;
    (13) SouthCoast Wind must establish clearance and shutdown zones, 
which must be measured using the radial distance from the pile being 
driven. All clearance zones must be confirmed to be free of marine 
mammals for 30 minutes immediately prior to the beginning of soft-start 
procedures or vibratory pile driving. If a marine mammal (other than a 
North Atlantic right whale) is detected within or about to enter the 
applicable clearance zones during this 30-minute time period, vibratory 
and impact pile driving must be delayed until the animal has been 
visually observed exiting the clearance zone or until a specific time 
period has elapsed with no further sightings. The specific time periods 
are 30 minutes for all baleen whale species and sperm whales and 15 
minutes for all other species;
    (14) For North Atlantic right whales, any visual observation by a 
PSO at any distance, or acoustic detection within the 10-km (6.2-mi) 
(pin pile) and 15-km (9.32-mi) (monopile) PAM clearance and shutdown 
zones must trigger a delay to the commencement or shutdown (if already 
begun) of pile driving. For any acoustic detection within the North 
Atlantic right whale PAM clearance and shutdown zones or sighting of 1 
or 2 North Atlantic right whales, SouthCoast Wind must delay 
commencement of or shutdown pile driving for 24 hours. For any sighting 
of 3 or more North Atlantic right whales, SouthCoast Wind must delay 
commencement of or shutdown pile driving for 48 hours. Prior to 
beginning clearance at the pile driving location after these periods, 
SouthCoast must conduct a vessel-based survey to visually clear the 10-
km (6.2-mi) zone, if installing pin piles that day, or 15-km (9.32-mi) 
zone, if installing monopiles.
    (15) If visibility decreases such that the entire clearance zone is 
not visible, at minimum, PSOs must be able to visually clear (i.e., 
confirm no marine mammals are present) the minimum visibility zone. The 
entire minimum visibility zone must be visible (i.e., not obscured by 
dark, rain, fog, etc.) for the full 60 minutes immediately prior to 
commencing impact and vibratory pile driving;
    (16) If a marine mammal is detected (visually or acoustically) 
entering or within the respective shutdown zone after pile driving has 
begun, the PSO or PAM operator must call for a shutdown of pile driving 
and SouthCoast Wind must stop pile driving immediately, unless shutdown 
is not practicable due to imminent risk of injury or loss of life to an 
individual or risk of damage to a vessel that creates risk of injury or 
loss of life for individuals, or the lead engineer determines there is 
risk of pile refusal or pile instability. If pile driving is not shut 
down due to one of these situations, SouthCoast Wind must

[[Page 53814]]

reduce hammer energy to the lowest level practicable to maintain 
stability;
    (17) If pile driving has been shut down due to the presence of a 
marine mammal other than a North Atlantic right whale, pile driving 
must not restart until either the marine mammal(s) has voluntarily left 
the species-specific clearance zone and has been visually or 
acoustically confirmed beyond that clearance zone, or, when specific 
time periods have elapsed with no further sightings or acoustic 
detections. The specific time periods are 30 minutes for all non-North 
Atlantic right whale baleen whale species and sperm whales and 15 
minutes for all other species. In cases where these criteria are not 
met, pile driving may restart only if necessary to maintain pile 
stability at which time SouthCoast Wind must use the lowest hammer 
energy practicable to maintain stability;
    (18) SouthCoast Wind must submit a Pile Driving Marine Mammal 
Monitoring Plan to NMFS Office of Protected Resources for review and 
approval at least 180 days prior to planned start of foundation pile 
driving and abide by the Plan if approved. SouthCoast Wind must obtain 
both NMFS Office of Protected Resources and NMFS Greater Atlantic 
Regional Fisheries Office Protected Resources Division's concurrence 
with this Plan prior to the start of any pile driving;
    (19) SouthCoast Wind must perform T-SFV measurements during 
installation of, at minimum, the first three WTG monopile foundations, 
first four WTG pin piles, and all OSP jacket foundation pin piles;
    (i) T-SFV measurements must continue until at least three 
consecutive monopiles or four consecutive pin piles demonstrate noise 
levels are at or below those modeled, assuming 10 decibels (dB) of 
attenuation. Subsequent T-SFV measurements are also required should 
larger piles be installed or if additional monopiles or pin piles are 
driven that may produce louder sound fields than those previously 
measured (e.g., from higher hammer energy, greater number of strikes);
    (ii) T-SFV measurements must be made at a minimum of four distances 
from the pile(s) being driven along a single transect in the direction 
of lowest transmission loss (i.e., projected lowest transmission loss 
coefficient), including, but not limited to, 750 m (2,460 ft) and three 
additional ranges selected such that measurement of modeled Level A 
harassment and Level B harassment isopleths are accurate, feasible, and 
avoids extrapolation (i.e., recorder spacing is approximately 
logarithmic and significant gaps near expected isopleths are avoided). 
At least one additional measurement at an azimuth 90 degrees from the 
transect array at 750 m (2,460 ft) must be made. At each location, 
there must be a near bottom and mid-water column hydrophone (acoustic 
recorder);
    (iii) If any of the T-SFV results indicate that distances to 
harassment isopleths were exceeded, then SouthCoast Wind must implement 
additional measures for all subsequent foundation installations to 
ensure the measured distances to the Level A harassment and Level B 
harassment threshold isopleths do not exceed those modeled assuming 10 
dB attenuation. SouthCoast Wind must also increase clearance, shutdown, 
and/or Level B harassment zone sizes to those identified by NMFS until 
T-SFV measurements on at least three additional monopiles or four pin 
piles demonstrate distances to harassment threshold isopleths meet or 
are less than those modeled assuming 10-dB of attenuation. For every 
1,500 m (4,900 ft) that a marine mammal clearance or shutdown zone is 
expanded, additional PSOs must be deployed from additional platforms/
vessels to ensure adequate and complete monitoring of the expanded 
clearance and/or shutdown zone(s), with each PSO responsible for 
scanning no more than 120 degrees ([deg]) out to a radius no greater 
than 1,500 m (4,900 ft). SouthCoast Wind must optimize the sound 
attenuation systems (e.g., ensure hose maintenance, pressure testing, 
etc.) to, at least, meet noise levels modeled, assuming 10-dB 
attenuation, within three monopiles or four pin piles, or else 
foundation installation activities must cease until NMFS and SouthCoast 
Wind can evaluate potential reasons for louder than anticipated noise 
levels. Alternatively, if SouthCoast determines T-SFV results 
demonstrate noise levels are within those modeled assuming 10 dB 
attenuation, SouthCoast may proceed to the next pile after submitting 
the interim report to NMFS;
    (20) SouthCoast Wind also must conduct abbreviated SFV, using at 
least one acoustic recorder (consisting of a bottom and mid-water 
column hydrophone) for every foundation for which T-SFV monitoring is 
not conducted. All abbreviated SFV data must be included in weekly 
reports. Any indications that distances to the identified Level A 
harassment and Level B harassment thresholds for marine mammals may be 
exceeded based on this abbreviated monitoring must be addressed by 
SouthCoast Wind in the weekly report, including an explanation of 
factors that contributed to the exceedance and corrective actions that 
were taken to avoid exceedance on subsequent piles. SouthCoast Wind 
must meet with NMFS within two business days of SouthCoast Wind's 
submission of a report that includes an exceedance to discuss if any 
additional action is necessary;
    (21) The SFV measurement systems must have a sensitivity for the 
expected sound levels from pile driving received at the nominal ranges 
throughout the installation of the pile. The frequency range of SFV 
measurement systems must cover the range of at least 20 hertz (Hz) to 
20 kilohertz (kHz). The SFV measurement systems must be designed to 
have omnidirectional sensitivity so that the broadband received level 
of all pile driving exceeds the system noise floor by at least 10 dB. 
The dynamic range of the SFV measurement system must be sufficient such 
that at each location, and the signals avoid poor signal-to-noise 
ratios for low amplitude signals and avoid clipping, nonlinearity, and 
saturation for high amplitude signals;
    (22) SouthCoast must ensure that all hydrophones used in pile 
installation SFV measurements systems have undergone a full system, 
traceable laboratory calibration conforming to International 
Electrotechnical Commission (IEC) 60565, or an equivalent standard 
procedure from a factory or accredited source, at a date not to exceed 
2 years before deployment, to guarantee each hydrophone receives 
accurate sound levels. Additional in situ calibration checks using a 
pistonphone must be performed before and after each hydrophone 
deployment. If the measurement system employs filters via hardware or 
software (e.g., high-pass, low-pass, etc.), which is not already 
accounted for by the calibration, the filter performance (i.e., the 
filter's frequency response) must be known, reported, and the data 
corrected for the filter's effect before analysis;
    (23) SouthCoast Wind must be prepared with additional equipment 
(e.g., hydrophones, recording devices, hydrophone calibrators, cables, 
batteries), which exceeds the amount of equipment necessary to perform 
the measurements, such that technical issues can be mitigated before 
measurement;
    (24) If any of the SFV measurements from any pile indicate that the 
distance to any isopleth of concern is greater than those modeled 
assuming 10-dB attenuation, before the next pile is installed, 
SouthCoast Wind must implement the following measures, as applicable: 
identify and propose for

[[Page 53815]]

review and concurrence; additional, modified, and/or alternative noise 
attenuation measures or operational changes that present a reasonable 
likelihood of reducing sound levels to the modeled distances; provide a 
written explanation to NMFS Office of Protected Resources supporting 
that determination, and request concurrence to proceed; and, following 
NMFS Office of Protected Resources' concurrence, deploy those 
additional measures on any subsequent piles that are installed (e.g., 
if threshold distances are exceeded on pile 1, then additional measures 
must be deployed before installing pile 2);
    (25) If SFV measurements indicate that ranges to isopleths 
corresponding to the Level A harassment and Level B harassment 
thresholds are less than the ranges predicted by modeling (assuming 10-
dB attenuation) for 3 consecutive monopiles or 4 consecutive pin piles, 
SouthCoast Wind may submit a request to NMFS Office of Protected 
Resources for a modification of the mitigation zones for non-North 
Atlantic right whale species. Mitigation zones for North Atlantic right 
whales cannot be decreased;
    (26) SouthCoast must measure background noise (i.e., noise absent 
pile driving) for 30 minutes before and after each pile installation;
    (27) SouthCoast must conduct SFV measurements upon commencement of 
turbine operations to estimate turbine operational source levels, in 
accordance with a NMFS-approved Foundation Installation Pile Driving 
SFV Plan. SFV must be conducted in the same manner as previously 
described in paragraph (13) of this section, with adjustments to 
measurement distances, number of hydrophones, and hydrophone 
sensitivities being made, as necessary; and
    (28) SouthCoast Wind must submit a SFV Plan for thorough and 
abbreviated SFV for foundation installation and WTG operations to NMFS 
Office of Protected Resources for review and approval at least 180 days 
prior to planned start of foundation installation activities and abide 
by the Plan if approved. Pile driving may not occur until NMFS provides 
SouthCoast concurrence that implementation of the SFV Plan meets the 
requirements in the LOA.
    (d) UXO/MEC detonation. The following requirements apply to 
Unexploded Ordnances and Munitions and Explosives of Concern (UXO/MEC) 
detonation:
    (1) Upon encountering a UXO/MEC, SouthCoast Wind can only resort to 
high-order removal (i.e., detonation) if all other means of removal are 
impracticable (i.e., As Low As Reasonably Practicable (ALARP) risk 
mitigation procedure)) and this determination must be documented and 
submitted to NMFS;
    (2) UXO/MEC detonations must not occur from December 1 through 
April 30;
    (3) UXO/MEC detonations must only occur during daylight hours (1 
hour after civil sunrise through 1.5 hours prior to civil sunset);
    (4) No more than one detonation can occur within a 24-hour period. 
No more than 10 detonations may occur throughout the effective period 
of these regulations;
    (5) SouthCoast Wind must deploy, at minimum, a double bubble 
curtain during all UXO/MEC detonations and comply with the following 
requirements related to noise abatement:
    (i) The bubble curtain(s) must distribute air bubbles using an air 
flow rate of at least 0.5 m\3\/(min*m). The bubble curtain(s) must 
surround 100 percent of the UXO/MEC detonation perimeter throughout the 
full depth of the water column. In the unforeseen event of a single 
compressor malfunction, the offshore personnel operating the bubble 
curtain(s) must make adjustments to the air supply and operating 
pressure such that the maximum possible noise attenuation performance 
of the bubble curtain(s) is achieved;
    (ii) The lowest bubble ring must be in contact with the seafloor 
for the full circumference of the ring, and the weights attached to the 
bottom ring must ensure 100-percent seafloor contact;
    (iii) No parts of the ring or other objects may prevent full 
seafloor contact;
    (iv) Construction contractors must train personnel in the proper 
balancing of airflow to the ring. Construction contractors must submit 
an inspection/performance report for approval by SouthCoast Wind within 
72 hours following the performance test. SouthCoast Wind must then 
submit that report to NMFS Office of Protected Resources;
    (v) Corrections to the bubble ring(s) to meet the performance 
standards in this paragraph (5) must occur prior to UXO/MEC 
detonations. If SouthCoast Wind uses a noise mitigation device in 
addition to the bubble curtain, SouthCoast Wind must maintain similar 
quality control measures as described in this paragraph (5); and
    (vi) SouthCoast Wind must inspect and carry out maintenance on the 
noise attenuation system prior to every UXO/MEC detonation and prepare 
and submit a Noise Attenuation System (NAS) inspection/performance 
report as soon as it is available and prior to the UXO/MEC detonation 
to NMFS Office of Protected Resources.
    (6) SouthCoast Wind must conduct SFV during all UXO/MEC detonations 
at a minimum of three locations (at two water depths at each location) 
from each detonation in a direction toward deeper water in accordance 
with the following requirements:
    (i) SouthCoast Wind must empirically determine source levels (peak 
and cumulative sound exposure level), the ranges to the isopleths 
corresponding to the Level A harassment and Level B harassment 
threshold isopleths in meters and the transmission loss coefficient(s). 
SouthCoast Wind may estimate ranges to the Level A harassment and Level 
B harassment isopleths by extrapolating from in situ measurements 
conducted at several distances from the detonation location monitored;
    (ii) The SFV measurement systems must have a sensitivity for the 
expected sound levels from detonations received at the nominal ranges 
throughout the detonation. The dynamic range of the SFV measurement 
systems must be sufficient such that at each location, the signals 
avoid poor signal-to-noise ratios for low amplitude signals and the 
signals avoid clipping, nonlinearity, and saturation for high amplitude 
signals;
    (iii) All hydrophones used in UXO/MEC SFV measurements systems are 
required to have undergone a full system, traceable laboratory 
calibration conforming to International Electrotechnical Commission 
(IEC) 60565, or an equivalent standard procedure, from a factory or 
accredited source to ensure the hydrophone receives accurate sound 
levels, at a date not to exceed 2 years before deployment. Additional 
in-situ calibration checks using a pistonphone are required to be 
performed before and after each hydrophone deployment. If the 
measurement system employs filters via hardware or software (e.g., 
high-pass, low-pass, etc.), which is not already accounted for by the 
calibration, the filter performance (i.e., the filter's frequency 
response) must be known, reported, and the data corrected before 
analysis;
    (iv) SouthCoast Wind must be prepared with additional equipment 
(hydrophones, recording devices, hydrophone calibrators, cables, 
batteries, etc.), which exceeds the amount of equipment necessary to 
perform the measurements, such that

[[Page 53816]]

technical issues can be mitigated before measurement;
    (v) SouthCoast Wind must submit SFV reports within 72 hours after 
each UXO/MEC detonation;
    (vi) If acoustic field measurements collected during UXO/MEC 
detonation indicate ranges to the isopleths, corresponding to Level A 
harassment and Level B harassment thresholds, are greater than the 
ranges predicted by modeling (assuming 10 dB attenuation), SouthCoast 
Wind must implement additional noise mitigation measures prior to the 
next UXO/MEC detonation. SouthCoast Wind must provide written 
notification to NMFS Office of Protected Resources of the changes 
planned for the next detonation within 24 hours of implementation. 
Subsequent UXO/MEC detonation activities must not occur until NMFS and 
SouthCoast Wind can evaluate the situation and ensure future 
detonations will not exceed noise levels modeled assuming 10-dB 
attenuation; and
    (vii) SouthCoast Wind must optimize the noise attenuation systems 
(e.g., ensure hose maintenance, pressure testing) to, at least, meet 
noise levels modeled, assuming 10-dB attenuation.
    (7) SouthCoast Wind must establish and implement clearance zones 
for UXO/MEC detonation using both visual and acoustic monitoring;
    (8) At least three on-duty PSOs must be stationed on each 
monitoring platform and be monitoring for 60 minutes prior to, during, 
and 30 minutes after each UXO/MEC detonation. The number of platforms 
is contingent upon the size of the UXO/MEC detonation to be identified 
in SouthCoast's UXO/MEC Detonation Marine Mammal Monitoring Plan and 
must be sufficient such that PSOs are able to visually clear the entire 
clearance zone. Concurrently, at least one PAM operator must be 
actively monitoring for marine mammals with PAM 60 minutes before, 
during, and 30 minutes after detonation; and
    (9) All clearance zones must be confirmed to be acoustically free 
of marine mammals for 30 minutes prior to a detonation. If a marine 
mammal is observed entering or within the relevant clearance zone prior 
to the initiation of a detonation, detonation must be delayed and must 
not begin until either the marine mammal(s) has voluntarily left the 
specific clearance zones and have been visually and acoustically 
confirmed beyond that clearance zone, or, when specific time periods 
have elapsed with no further sightings or acoustic detections. The 
specific time periods are 30 minutes for all baleen whale species and 
sperm whales and 15 minutes for all other species.
    (e) HRG surveys. The following requirements apply to HRG surveys 
operating sub-bottom profilers (SBPs) (e.g., boomers, sparkers, and 
Compressed High Intensity Radiated Pulse (CHIRPS)) (hereinafter 
referred to as ``acoustic sources''):
    (1) SouthCoast Wind must establish and implement clearance and 
shutdown zones for HRG surveys using visual monitoring. These zones 
must be measured using the radial distance(s) from the acoustic 
source(s) currently in use;
    (2) SouthCoast must utilize PSO(s), as described in Sec.  
217.335(e). Visual monitoring must begin no less than 30 minutes prior 
to initiation of specified acoustic sources and must continue until 30 
minutes after use of specified acoustic sources ceases. Any PSO on duty 
has the authority to delay the start of survey operations or shutdown 
operations if a marine mammal is detected within the applicable zones. 
When delay or shutdown is instructed by a PSO, the mitigative action 
must be taken and any dispute resolved only following deactivation;
    (3) Prior to starting the survey and after receiving confirmation 
from the PSOs that the clearance zone is clear of any marine mammals, 
SouthCoast Wind is required to ramp-up acoustic sources to half power 
for 5 minutes prior to commencing full power, unless the equipment 
operates on a binary on/off switch (in which case ramp-up is not 
required). Any ramp-up of acoustic sources may only commence when 
visual clearance zones are fully visible (e.g., not obscured by 
darkness, rain, fog, etc.) and clear of marine mammals, as determined 
by the Lead PSO, for at least 30 minutes immediately prior to the 
initiation of survey activities using a specified acoustic source. 
Ramp-ups must be scheduled so as to minimize the time spent with the 
source activated;
    (4) Prior to a ramp-up procedure starting, the acoustic source 
operator must notify the Lead PSO of the planned start of ramp-up. The 
notification time must not be less than 60 minutes prior to the planned 
ramp-up or activation in order to allow the PSO(s) time to monitor the 
clearance zone(s) for 30 minutes prior to the initiation of ramp-up or 
activation (pre-start clearance). During this 30-minute clearance 
period, the entire applicable clearance zones must be visible;
    (5) A PSO conducting clearance observations must be notified again 
immediately prior to reinitiating ramp-up procedures and the operator 
must receive confirmation from the PSO to proceed;
    (6) If a marine mammal is observed within a clearance zone during 
the 30 minute clearance period, ramp-up or acoustic surveys may not 
begin until the animal(s) has been observed voluntarily exiting its 
respective clearance zone or until a specific time period has elapsed 
with no further sighting. The specific time periods are 30 minutes for 
all baleen whale species and sperm whales and 15 minutes for all other 
species;
    (7) In any case when the clearance process has begun in conditions 
with good visibility, including via the use of night vision/reduced 
visibility monitoring equipment (infrared (IR)/thermal camera), and the 
Lead PSO has determined that the clearance zones are clear of marine 
mammals, survey operations may commence (i.e., no delay is required) 
despite periods of inclement weather and/or loss of daylight. Ramp-up 
may occur at times of poor visibility, including nighttime, if required 
visual monitoring has occurred with no detections of marine mammals in 
the 30 minutes prior to beginning ramp-up;
    (8) Once the survey has commenced, SouthCoast Wind must shut down 
acoustic sources if a marine mammal enters a respective shutdown zone. 
In cases when the shutdown zones become obscured for brief periods 
(less than 30 minutes) due to inclement weather, survey operations 
would be allowed to continue (i.e., no shutdown is required) so long as 
no marine mammals have been detected. The shutdown requirement does not 
apply to small delphinids of the following genera: Delphinus, Stenella, 
Lagenorhynchus, and Tursiops. If there is uncertainty regarding the 
identification of a marine mammal species (i.e., whether the observed 
marine mammal belongs to one of the delphinid genera for which shutdown 
is waived), the PSOs must use their best professional judgment in 
making the decision to call for a shutdown. Shutdown is required if a 
delphinid that belongs to a genus other than those specified in this 
paragraph of this section is detected in the shutdown zone;
    (9) If an acoustic source has been shut down due to the presence of 
a marine mammal, the use of an acoustic source may not commence or 
resume until the animal(s) has been confirmed to have left the Level B 
harassment zone or until a full 30 minutes for all baleen whale species 
and sperm whales and 15 minutes for all other species have elapsed with 
no further sighting. If an acoustic source is shut down for reasons 
other than mitigation (e.g., mechanical

[[Page 53817]]

difficulty) for less than 30 minutes, it may be activated again without 
ramp-up only if PSOs have maintained constant observation and no 
additional detections of any marine mammal occurred within the 
respective shutdown zones. If an acoustic source is shut down for a 
period longer than 30 minutes, then all clearance and ramp-up 
procedures must be initiated;
    (10) If multiple HRG vessels are operating concurrently, any 
observations of marine mammals must be communicated to PSOs on all 
nearby survey vessels; and
    (11) Should an autonomous survey vehicle (ASV) be used during HRG 
surveys, the ASV must remain with 800 m (2,635 ft) of the primary 
vessel while conducting survey operations; two PSOs must be stationed 
on the mother vessel at the best vantage points to monitor the 
clearance and shutdown zones around the ASV; at least one PSO must 
monitor the output of a thermal high-definition camera installed on the 
mother vessel to monitor the field-of-view around the ASV using a hand-
held tablet, and during periods of reduced visibility (e.g., darkness, 
rain, or fog), PSOs must use night-vision goggles with thermal clip-ons 
and a hand-held spotlight to monitor the clearance and shutdown zones 
around the ASV.
    (f) Fisheries Monitoring Surveys. The following measures apply 
during fisheries monitoring surveys and must be implemented by 
SouthCoast Wind:
    (1) Marine mammal monitoring must be conducted within 1 nmi (1.85 
km) from the planned survey location by the trained captain and/or a 
member of the scientific crew for 15 minutes prior to deploying gear, 
throughout gear deployment and use, and for 15 minutes after haul back;
    (2) All captains and crew conducting fishery surveys must be 
trained in marine mammal detection and identification;
    (3) Gear must not be deployed if there is a risk of interaction 
with marine mammals. Gear must not be deployed until a minimum of 15 
consecutive minutes have elapsed during which no marine mammal 
sightings within 1 nmi (1,852 m) of the sampling station have occurred;
    (4) If marine mammals are sighted within 1 nm of the planned 
location (i.e., station) within the 15 minutes prior to gear 
deployment, then SouthCoast Wind must move the vessel away from the 
marine mammal to a different section of the sampling area. If, after 
moving on, marine mammals are still visible from the vessel, SouthCoast 
Wind must move again to an area visibly clear of marine mammals or skip 
the station;
    (5) If a marine mammal is at risk of interacting with deployed gear 
or set, all gear must be immediately removed from the water. If marine 
mammals are sighted before the gear is fully removed from the water, 
the vessel must slow its speed and maneuver the vessel away from the 
animals to minimize potential interactions with the observed animal;
    (6) Survey gear must be deployed as soon as possible once the 
vessel arrives on station and after fulfilling the requirements in 
(g)(1) and (g)(3);
    (7) SouthCoast Wind must maintain visual marine mammal monitoring 
effort during the entire period of time that gear is in the water 
(i.e., throughout gear deployment, fishing, and retrieval). If marine 
mammals are sighted before the gear is fully removed from the water, 
SouthCoast Wind will take the most appropriate action to avoid marine 
mammal interaction;
    (8) All fisheries monitoring gear must be fully cleaned and 
repaired (if damaged) before each use/deployment;
    (9) SouthCoast Wind's fixed gear must comply with the Atlantic 
Large Whale Take Reduction Plan regulations at 50 CFR 229.32 during 
fisheries monitoring surveys;
    (10) Trawl tows must be limited to a maximum of 20 minute trawl-
time and trawl tows must not exceed at a speed of 3.0 knots (3.5 mph);
    (11) All gear must be emptied as close to the deck/sorting area and 
as quickly as possible after retrieval;
    (12) During trawl surveys, vessel or scientific crew must open the 
cod end of the trawl net close to the deck in order to avoid injury to 
animals that may be caught in the gear;
    (13) All fishery survey-related lines must include the breaking 
strength of all lines being less than 1,700 pounds (lbs; 771 kilograms 
(kg)). This may be accomplished by using whole buoy line that has a 
breaking strength of 1,700 lbs (771 kg); or buoy line with weak inserts 
that result in line having an overall breaking strength of 1,700 lbs 
(771 kg);
    (14) During any survey that uses vertical lines, buoy lines must be 
weighted and must not float at the surface of the water. All 
groundlines must be composed entirely of sinking lines. Buoy lines must 
utilize weak links. Weak links must break cleanly leaving behind the 
bitter end of the line. The bitter end of the line must be free of any 
knots when the weak link breaks. Splices are not considered to be 
knots. The attachment of buoys, toggles, or other floatation devices to 
groundlines is prohibited;
    (15) All in-water survey gear, including buoys, must be properly 
labeled with the scientific permit number or identification as 
SouthCoast Wind's research gear. All labels and markings on the gear, 
buoys, and buoy lines must also be compliant with the applicable 
regulations, and all buoy markings must comply with instructions 
received by the NOAA Greater Atlantic Regional Fisheries Office 
Protected Resources Division;
    (16) All survey gear must be removed from the water whenever not in 
active survey use (i.e., no wet storage);
    (17) All reasonable efforts that do not compromise human safety 
must be undertaken to recover gear; and
    (18) Any lost gear associated with the fishery surveys must be 
reported to the NOAA Greater Atlantic Regional Fisheries Office 
Protected Resources Division within 24 hours.


Sec.  217.335  Monitoring and Reporting Requirements.

    SouthCoast Wind must implement the following monitoring and 
reporting requirements when conducting the specified activities (see 
Sec.  217.330(c)):
    (a) Protected species observer (PSO) and passive acoustic 
monitoring (PAM) operator qualifications: SouthCoast Wind must 
implement the following measures applicable to PSOs and PAM operators:
    (1) SouthCoast Wind must use NMFS-approved PSOs and PAM operators 
that are employed by a third-party observer provider. PSOs and PAM 
operators must have no tasks other than to conduct observational 
effort, collect data, and communicate with and instruct relevant 
personnel regarding the presence of marine mammals and mitigation 
requirements;
    (2) All PSOs and PAM operators must have successfully attained a 
bachelor's degree from an accredited college or university with a major 
in one of the natural sciences. The educational requirements may be 
waived if the PSO or PAM operator has acquired the relevant experience 
and skills (see Sec.  217.335(a)(3)) for visually and/or acoustically 
detecting marine mammals in a range of environmental conditions (e.g., 
sea state, visibility) within zone sizes equivalent to the clearance 
and shutdown zones required by these regulations. Requests for such a 
waiver must be submitted to NMFS Office of Protected Resources prior to 
or when SouthCoast Wind requests PSO and PAM operator approvals and 
must include written justification describing alternative experience. 
Alternate experience that may be considered includes, but is not 
limited to,

[[Page 53818]]

conducting academic, commercial, or government-sponsored marine mammal 
visual and/or acoustic surveys or previous work experience as a PSO/PAM 
operator. All PSO's and PAM operators should demonstrate good standing 
and consistently good performance of all assigned duties;
    (3) PSOs must have visual acuity in both eyes (with correction of 
vision being permissible) sufficient enough to discern moving targets 
on the water's surface with the ability to estimate the target size and 
distance (binocular use is allowable); ability to conduct field 
observations and collect data according to the assigned protocols, 
writing skills sufficient to document observations and the ability to 
communicate orally by radio or in-person with project personnel to 
provide real-time information on marine mammals observed in the area;
    (4) All PSOs must be trained to identify northwestern Atlantic 
Ocean marine mammal species and behaviors and be able to conduct field 
observations and collect data according to assigned protocols. 
Additionally, PSOs must have the ability to work with all required and 
relevant software and equipment necessary during observations described 
in paragraphs (b)(2) and (b)(3) of this section;
    (5) All PSOs and PAM operators must have successfully completed a 
PSO, PAM, or refresher training course within the last 5 years and 
obtained a certificate of course completion that must be submitted to 
NMFS. This requirement is waived for any PSOs and PAM operators that 
completed a relevant training course more than five years prior to 
seeking approval but have been working consistently as a PSO or PAM 
operator within the past five years;
    (6) At least one on-duty PSO and PAM operator, where applicable, 
per platform must be designated as a Lead during each of the specified 
activities;
    (7) PSOs and PAM operators are responsible for obtaining NMFS' 
approval. NMFS may approve PSOs as conditional or unconditional. An 
unconditionally approved PSO is one who has completed training within 
the last 5 years and attained the necessary experience (i.e., 
demonstrate experience with monitoring for marine mammals at clearance 
and shutdown zone sizes similar to those produced during the respective 
activity) or for PSOs and PAM operators who completed training more 
than five years previously and have worked in the specified role 
consistently for at least the past 5 years. A conditionally-approved 
PSO may be one who has completed training in the last 5 years but has 
not yet attained the requisite field experience. To qualify as a Lead 
PSO or PAM operator, the person must be unconditionally approved and 
demonstrate that they have a minimum of 90 days of at-sea experience in 
the specific role, with the conclusion of the most recent relevant 
experience not more than 18 months previous to deployment, and must 
also have experience specifically monitoring baleen whale species;
    (7) PSOs for HRG surveys may be unconditionally or conditionally 
approved. A conditionally approved PSO for HRG surveys must be paired 
with an unconditionally approved PSO;
    (8) PSOs and PAM operators for foundation installation and UXO 
detonation must be unconditionally approved;
    (9) SouthCoast Wind must submit NMFS-approved PSO and PAM operator 
resumes to NMFS Office of Protected Resources for review and 
confirmation of their approval for specific roles at least 90 days 
prior to commencement of the activities requiring PSOs/PAM operators or 
30 days prior to when new PSOs/PAM operators are required after 
activities have commenced. Resumes must include information related to 
relevant education, experience, and training, including dates, duration 
(i.e., number of days as a PSO or PAM operator per project), location, 
and description of each prior PSO or PAM operator experience (i.e., 
zone sizes monitored, how monitoring supported mitigation; PAM system/
software utilized);
    (10) For prospective PSOs and PAM operators not previously approved 
by NMFS or for PSOs and PAM operators whose approval is not current 
(i.e., approval date is more than 5 years prior to the start of 
monitoring duties), SouthCoast Wind must submit the list of pre-
approved PSOs and PAM operators for qualification verification at least 
60 days prior to PSO and PAM operator use. Resumes must include 
information detailed in 217.335(a)(9). Resumes must be accompanied by 
certificate of completion of a NMFS-approved PSO and/or PAM training/
course;
    (11) To be approved as a PAM operator, the person must meet the 
following qualifications: the PAM operator must have completed a PAM 
Operator training course, and demonstrate prior experience using PAM 
software, equipment, and real-time acoustic detection systems. They 
must demonstrate that they have prior experience independently 
analyzing archived and/or real-time PAM data to identify and classify 
baleen whale and other marine mammal vocalizations by species, 
including North Atlantic right whale and humpback whale vocalizations, 
and experience with deconfliction of multiple species' vocalizations 
that are similar and/or received concurrently. PAM operators must be 
independent observers (i.e., not construction personnel), trained to 
use relevant project-specific PAM software and equipment, and must also 
be able to test software and hardware functionality prior to beginning 
real-time monitoring. The PAM operator must be able to identify and 
classify marine mammal acoustic detections by species in real-time 
(prioritizing North Atlantic right whales and noting other marine 
mammals vocalizations, when detected). At a minimum, for each acoustic 
detection, the PAM operator must be able to categorically determine 
whether a North Atlantic right whale is detected, possibly detected, or 
not detected, and notify the Lead PSO of any confirmed or possible 
detections, including baleen whale detections that cannot be identified 
to species. If the PAM software is capable of localization of sounds or 
deriving bearings and distance, the PAM operators must demonstrate 
experience using this technique;
    (12) PSOs may work as PAM operators and vice versa if NMFS approves 
each individual for both roles; however, they may only perform one role 
at any one time and must not exceed work time restrictions, which must 
be tallied cumulatively; and
    (13) All PSOs and PAM operators must complete a Permits and 
Environmental Compliance Plan training that must be held by the Project 
compliance representative(s) prior to the start of in-water project 
activities and whenever new PSOs and PAM operators join the marine 
mammal monitoring team. PSOs and PAM operators must also complete 
training and orientation with the construction operation to provide for 
personal safety;
    (b) General PSO and PAM operator requirements. The following 
measures apply to PSOs and PAM operators and must be implemented by 
SouthCoast Wind: (1) All PSOs must be located at the best vantage 
point(s) on any platform, as determined by the Lead PSO, in order to 
collectively obtain 360-degree visual coverage of the entire clearance 
and shutdown zones around the activity area and as much of the Level B 
harassment zone as possible. PAM operators may be located on a vessel 
or remotely on-shore but must have a computer station equipped with a 
data collection software system and acoustic data analysis software 
available wherever they are stationed, and data or data products must 
be streamed in real-

[[Page 53819]]

time or in near real-time to allow PAM operators to provide assistance 
to on-duty PSOs in determining if mitigation is required (i.e., delay 
or shutdown);
    (2) PSOs must use high magnification (25x) binoculars, standard 
handheld (7x) binoculars, and the naked eye to search continuously for 
marine mammals during visual monitoring. During foundation 
installation, at least three PSOs on each dedicated PSO vessel must be 
equipped with functional Big Eye binoculars (e.g., 25 x 150; 2.7 view 
angle; individual ocular focus; height control). These must be pedestal 
mounted on the deck at the best vantage point that provides for optimal 
sea surface observation and PSO safety. PAM operators must use a NMFS-
approved PAM system to conduct acoustic monitoring;
    (3) During periods of low visibility (e.g., darkness, rain, fog, 
poor weather conditions, etc.), PSOs must use alternative technology 
(e.g., infrared or thermal cameras) to monitor the mitigation zones;
    (4) PSOs and PAM operators must not exceed 4 consecutive watch 
hours on duty at any time, must have a 2-hour (minimum) break between 
watches, and must not exceed a combined watch schedule of more than 12 
hours in a 24-hour period; and
    (5) SouthCoast Wind must ensure that PSOs conduct, as rotation 
schedules allow, observations for comparison of sighting rates and 
behavior with and without use of the specified acoustic sources. Off-
effort PSO monitoring must be reflected in the PSO monitoring reports.
    (c) Reporting. SouthCoast Wind must comply with the following 
reporting measures:
    (1) Prior to initiation of project activities, SouthCoast Wind must 
demonstrate in a report submitted to NMFS Office of Protected Resources 
([email protected]) that all required training for 
SouthCoast Wind personnel, including the vessel crews, vessel captains, 
PSOs, and PAM operators has been completed;
    (2) SouthCoast Wind must use a standardized reporting system. All 
data collected related to the Project must be recorded using industry-
standard software that is installed on field laptops and/or tablets. 
Unless stated otherwise, all reports must be submitted to NMFS Office 
of Protected Resources ([email protected]), dates must 
be in MM/DD/YYYY format, and location information must be provided in 
Decimal Degrees and with the coordinate system information (e.g., 
NAD83, WGS84);
    (3) Full detection data, metadata, and location of recorders (or 
GPS tracks, if applicable) from all real-time hydrophones used for 
monitoring during foundation installation and UXO/MEC detonations must 
be submitted within 90 calendar days following completion of activities 
requiring PAM for mitigation via the International Organization for 
Standardization (ISO) standard metadata forms available on the NMFS 
Passive Acoustic Reporting System website (https://www.fisheries.noaa.gov/resource/document/passive-acoustic-reportingsystem-templates). Submit the completed data templates to 
[email protected]. The full acoustic recordings from real-time 
systems must also be sent to the National Centers for Environmental 
Information (NCEI) for archiving within 90 days following completion of 
activities requiring PAM for mitigation. Submission details can be 
found at: https://www.ncei.noaa.gov/products/passive-acoustic-data;
    (4) SouthCoast Wind must compile and submit weekly reports during 
foundation installation containing, at minimum, the marine mammal 
monitoring and abbreviated SFV data to NMFS Office of Protected 
Resources ([email protected]). Weekly reports are due 
on Wednesday for the previous week (Sunday-Saturday);
    (5) SouthCoast Wind must compile and submit monthly reports during 
foundation installation containing, at minimum, data as described in 
the weekly reports to NMFS Office of Protected Resources 
([email protected]). Monthly reports are due on the 
15th of the month for the previous month;
    (6) SouthCoast Wind must submit a draft annual marine mammal 
monitoring report to NMFS ([email protected]) no later 
than March 31, annually that contains data for all specified 
activities. The final annual marine mammal monitoring report must be 
prepared and submitted within 30 calendar days following the receipt of 
any comments from NMFS on the draft report;
    (7) SouthCoast Wind must submit the T-SFV interim report no later 
than 48 hours after cessation of pile driving for a given foundation 
installation. In addition to the 48-hour interim reports, SouthCoast 
Wind must submit a draft annual SFV report to NMFS 
([email protected]) no later than 90 days after SFV is 
completed for the year. The final annual SFV report must be prepared 
and submitted within 30 calendar days (or longer upon approval by NMFS) 
following the receipt of any comments from NMFS on the draft report;
    (8) SouthCoast Wind must submit its draft final 5-year report to 
NMFS ([email protected]) on all visual and acoustic 
monitoring, including SFV monitoring, within 90 calendar days of the 
completion of the specified activities. A 5-year report must be 
prepared and submitted within 60 calendar days (or longer upon approval 
by NMFS) following receipt of any NMFS Office of Protected Resources 
comments on the draft report;
    (9) SouthCoast Wind must submit SFV results from UXO/MEC detonation 
monitoring in a report prior to detonating a subsequent UXO/MEC or 
within the relevant weekly report, whichever comes first;
    (10) SouthCoast must submit bubble curtain performance reports 
within 48 hours of each bubble curtain deployment;
    (11) SouthCoast Wind must provide NMFS Office of Protected 
Resources with notification of planned UXO/MEC detonation as soon as 
possible but at least 48 hours prior to the planned detonation unless 
this 48-hour notification requirement would create delays to the 
detonation that would result in imminent risk of human life or safety. 
This notification must include the coordinates of the planned 
detonation, the estimated charge size, and any other information 
available on the characteristics of the UXO/MEC;
    (13) SouthCoast Wind must submit a report to the NMFS Office of 
Protected Resources (insert ITP monitoring email) within 24 hours if an 
exemption to any of the requirements in the regulations and LOA is 
taken;
    (14) SouthCoast Wind must submit reports on all North Atlantic 
right whale sightings and any dead or entangled marine mammal sightings 
to NMFS Office of Protected Resources 
([email protected]); and
    (15) SouthCoast Wind must report any lost gear associated with the 
fishery surveys to the NOAA Greater Atlantic Regional Fisheries Office 
Protected Resources Division ([email protected]) as soon 
as possible or within 24 hours of the documented time of missing or 
lost gear.


Sec.  217.336  Letter of Authorization.

    (a) To incidentally take marine mammals pursuant to these 
regulations, SouthCoast Wind must apply for and obtain an LOA;
    (b) An LOA, unless suspended or revoked, may be effective for a 
period of

[[Page 53820]]

time not to exceed the effective period of this subpart;
    (c) If an LOA expires prior to the expiration date of these 
regulations, SouthCoast Wind may apply for and obtain a renewal of the 
LOA;
    (d) In the event of projected changes to the activity or to 
mitigation and monitoring measures required by an LOA, SouthCoast Wind 
must apply for and obtain a modification of the LOA as described in 
Sec.  217.337; and
    (e) The LOA must set forth:
    (1) Permissible methods of incidental taking;
    (2) Means of effecting the least practicable adverse impact (i.e., 
mitigation) on the species, its habitat, and on the availability of the 
species for subsistence uses; and
    (3) Requirements for monitoring and reporting.
    (f) Issuance of the LOA must be based on a determination that the 
level of taking must be consistent with the findings made for the total 
taking allowable under this subpart; and
    (g) Notice of issuance or denial of an LOA must be published in the 
Federal Register within 30 days of a determination.


Sec.  217.337  Modifications of Letter of Authorization.

    (a) A LOA issued under Sec. Sec.  216.106 and 217.336 of this 
section for the activities identified in Sec.  217.330(c) shall be 
modified upon request by SouthCoast Wind, provided that:
    (1) The specified activity and mitigation, monitoring, and 
reporting measures, as well as the anticipated impacts, are the same as 
those described and analyzed for this subpart (excluding changes made 
pursuant to the adaptive management provision in paragraph (c)(1) of 
this section); and
    (2) NMFS determines that the mitigation, monitoring, or reporting 
measures required by the previous LOA under this subpart were 
implemented.
    (b) For a LOA modification request by the applicant that includes 
changes to the activity or the mitigation, monitoring, or reporting 
measures (excluding changes made pursuant to the adaptive management 
provision in paragraph (c)(1) of this section), the LOA shall be 
modified, provided that:
    (1) NMFS determines that the changes to the activity or the 
mitigation, monitoring, or reporting do not change the findings made 
for the regulations in this subpart and do not result in more than a 
minor change in the total estimated number of takes (or distribution by 
species or years); and
    (2) NMFS may publish a notice of proposed modified LOA in the 
Federal Register, including the associated analysis of the change, and 
solicit public comment before issuing the LOA.
    (c) A LOA issued under Sec. Sec.  216.106 and 217.336 of this 
section for the activities identified in Sec.  217.330(c) may be 
modified by NMFS under the following circumstances:
    (1) Through adaptive management, NMFS may modify (including remove, 
revise, or add to) the existing mitigation, monitoring, or reporting 
measures after consulting with SouthCoast Wind regarding the 
practicability of the modifications, if doing so creates a reasonable 
likelihood of more effectively accomplishing the goals of the 
mitigation and monitoring measures set forth in this subpart.
    (i) Possible sources of data that could contribute to the decision 
to modify the mitigation, monitoring, or reporting measures in an LOA 
include, but are not limited to:
    (A) Results from SouthCoast Wind's monitoring;
    (B) Results from other marine mammals and/or sound research or 
studies; and
    (C) Any information that reveals marine mammals may have been taken 
in a manner, extent, or number not authorized by this subpart or 
subsequent LOA.
    (ii) If, through adaptive management, the modifications to the 
mitigation, monitoring, or reporting measures are substantial, NMFS 
shall publish a notice of proposed LOA in the Federal Register and 
solicit public comment; and
    (2) If NMFS determines that an emergency exists that poses a 
significant risk to the well-being of the species or stocks of marine 
mammals specified in the LOA issued pursuant to Sec. Sec.  216.106 and 
217.336 of this section, a LOA may be modified without prior notice or 
opportunity for public comment. Notice would be published in the 
Federal Register within 30 days of the action.


Sec. Sec.  217.338-217.339  [Reserved]

[FR Doc. 2024-13770 Filed 6-25-24; 8:45 am]
BILLING CODE 3510-22-P