Proposed Rule2024-13770
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the SouthCoast Wind Project Offshore Massachusetts
Primary source
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Published
June 27, 2024
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
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.
Full Text
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[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 [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[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 <a href="https://www.regulations.gov/docket/">https://www.regulations.gov/docket/</a> NOAA-NMFS-2024-0074. Submit all
electronic public comments via the Federal e- Portal. Visit <a href="https://www.regulations.gov">https://www.regulations.gov</a> 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
<a href="https://www.regulations.gov">https://www.regulations.gov</a> without change. All personal identifying
information (e.g., name, address), confidential business information,
or otherwise sensitive information submitted voluntarily by the sender
will be publicly accessible. NMFS will accept anonymous comments (enter
``N/A'' in the required fields if you wish to remain anonymous).
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: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable</a>. In case of
problems accessing these documents, please call the contact listed
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:
<bullet> 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);
<bullet> 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);
<bullet> 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);
<bullet> Serious Injury--any injury that will likely result in
mortality (50 CFR 216.3);
<bullet> 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
<bullet> 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:
<bullet> 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);
<bullet> 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;
<bullet> 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);
<bullet> 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;
<bullet> 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;
<bullet> 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;
<bullet> 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;
<bullet> Requiring training for all SouthCoast Project personnel to
ensure marine mammal protocols and procedures are understood;
<bullet> 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;
<bullet> Establishing minimum visibility and PAM monitoring zones
during foundation impact pile driving and detonations of UXO/MECs;
<bullet> 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;
<bullet> 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;
<bullet> Requiring SFV during the operational phase of the
SouthCoast Project;
<bullet> Implementing soft-starts during pile driving and ramp-up
during the use of high-resolution geophysical (HRG) marine site
characterization survey equipment;
<bullet> Requiring various vessel strike avoidance measures;
<bullet> 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;
<bullet> 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
<bullet> 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: <a href="https://www.permits.performance.gov/permitting-project/southcoast-wind-energy-llc-southcoast-wind">https://www.permits.performance.gov/permitting-project/southcoast-wind-energy-llc-southcoast-wind</a>.
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: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable</a>.
On August 1, 2022, NMFS announced proposed changes to the existing
North Atlantic right whale vessel speed regulations to further reduce
the likelihood of mortalities and serious injuries to endangered right
whales from vessel collisions, which are a leading cause of the
species' decline and a primary factor in an ongoing Unusual Mortality
Event (87 FR 46921). Should a final vessel speed rule be 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):
<bullet> 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
<bullet> 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:
<bullet> Shallow penetration sub-bottom profilers (SBPs) to map the
near-surface stratigraphy (top 0 to 5 m (0 to 16 ft) of sediment below
seabed). A CHIRP system emits sonar pulses that increase in frequency
over time. The pulse length frequency range can be adjusted to meet
Projectvariables. These are typically mounted on the hull of the vessel
or from a side pole.
<bullet> Medium penetration SBPs (boomers) to map deeper subsurface
stratigraphy as needed. A boomer is a broad-band sound source operating
in the 3.5 Hz to 10 kHz frequency range. This system is typically
mounted on a sled and towed behind the vessel.
<bullet> Medium penetration SBPs (sparkers) to map deeper
subsurface stratigraphy as needed. A sparker creates acoustic pulses
from 50 Hz to 4 kHz omni-directionally from the source that can
penetrate several hundred meters into the seafloor. These are typically
towed behind the vessel with adjacent hydrophone arrays to receive the
return signals.
Table 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) (<a href="https://media.fisheries.bnoaa.gov/dam-migration/2019_sars_atlantic_atlanticbspottedbdolphin.pdf">https://media.fisheries.bnoaa.gov/dam-migration/2019_sars_atlantic_atlanticbspottedbdolphin.pdf</a>).
Additional information regarding population trends and threats may
be found in NMFS' Stock Assessment Reports (SARs; <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports</a>) and more general information about
these species (e.g., physical and behavioral descriptions) may be found
on NMFS' website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
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: <a href="https://www.fws.gov/species/manatee-trichechus-manatus">https://www.fws.gov/species/manatee-trichechus-manatus</a>.
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 <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports</a>.
Table 5--Marine Mammal Species \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
(<a href="https://www.marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies">https://www.marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies</a>/; 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 (<a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-southcoast-wind-llc-construction-southcoast-wind-offshore-wind">https://www.fisheries.noaa.gov/action/incidental-take-authorization-southcoast-wind-llc-construction-southcoast-wind-offshore-wind</a>), the SARs (<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>), and NMFS' website (<a href="https://www.fisheries.noaa.gov/species-directory/marine-mammals">https://www.fisheries.noaa.gov/species-directory/marine-mammals</a>), we provide
further detail below informing the baseline for select species (e.g.,
information regarding current UMEs and known important habitat areas,
such as Biologically Important Areas (BIAs; <a href="https://oceannoise.noaa.gov/biologically-important-areas">https://oceannoise.noaa.gov/biologically-important-areas</a>) (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. (<a href="https://www.fisheries.noaa.gov/resource/document/north-atlantic-right-whale-5-year-review">https://www.fisheries.noaa.gov/resource/document/north-atlantic-right-whale-5-year-review</a>). 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
(<a href="https://www.fisheries.noaa.gov/topic/endangered-species-conservation/species-in-the-spotlight">https://www.fisheries.noaa.gov/topic/endangered-species-conservation/species-in-the-spotlight</a>).
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 <a href="https://www.fisheries.noaa.gov/national/marine-life-distress/2017-2023-north-atlantic-right-whale-unusual-mortality-event">https://www.fisheries.noaa.gov/national/marine-life-distress/2017-2023-north-atlantic-right-whale-unusual-mortality-event</a>.
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: <a href="https://www.fisheries.noaa.gov/national/marine-life-distress/active-and-closed-unusual-mortality-events">https://www.fisheries.noaa.gov/national/marine-life-distress/active-and-closed-unusual-mortality-events</a>.
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: <a href="https://www.fisheries.noaa.gov/national/marine-life-distress/2017-2022-minke-whale-unusual-mortality-event-along-atlantic-coast">https://www.fisheries.noaa.gov/national/marine-life-distress/2017-2022-minke-whale-unusual-mortality-event-along-atlantic-coast</a>.
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:
<a href="https://www.fisheries.noaa.gov/new-england-mid-atlantic/marine-life-distress/2018-2020-pinniped-unusual-mortality-event-along">https://www.fisheries.noaa.gov/new-england-mid-atlantic/marine-life-distress/2018-2020-pinniped-unusual-mortality-event-along</a>.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Current data indicate that not all marine
mammal species have equal hearing capabilities (e.g., Richardson et
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect
this, Southall et al. (2007) recommended that marine mammals be divided
into functional hearing groups based on directly measured or estimated
hearing ranges on the basis of available behavioral response data,
audiograms derived using auditory evoked potential techniques,
anatomical modeling, and other data. Note that no direct measurements
of hearing ability have been successfully completed for mysticetes
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65
decibel (dB) threshold from the normalized composite audiograms, with
the exception for lower limits for low-frequency cetaceans where the
lower bound was deemed to be biologically implausible and the lower
bound from Southall et al. (2007) retained. Marine mammal hearing
groups and their associated hearing ranges are provided in table 6.
Table 6--Marine Mammal Hearing Groups (NMFS, 2018)
------------------------------------------------------------------------
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 <a href="https://dosits.org/">https://dosits.org/</a>.
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;
SEL<INF>ss</INF>) or calculated over periods containing multiple pulses
(SEL<INF>cum</INF>). Cumulative SEL represents the total energy
accumulated by a receiver over a defined time window or during an
event. The SEL metric is useful because it allows sound exposures of
different durations to be related to one another in terms of total
acoustic energy. The duration of a sound event and the number of
pulses, however, should be specified as there is no accepted standard
duration over which the summation of energy is measured.
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 he
[…truncated; see source link]Indexed from Federal Register on June 27, 2024.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.