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

AGENCY:

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

ACTION:

Final rule; notification of issuance of letter of authorization.

SUMMARY:

In accordance with the regulations implementing the Marine Mammal Protection Act (MMPA), as amended, NMFS hereby promulgates regulations to govern the incidental taking of marine mammals by Avangrid Renewables, LLC, (Avangrid), the parent company of the original applicant, Park City Wind, LLC (Park City Wind), during the construction of the New England Wind Project (the Project), an offshore wind energy project, developed in two phases, known as Park City Wind (phase 1) and Commonwealth Wind (phase 2), in Federal and State waters off of Massachusetts, specifically within the Bureau of Ocean Energy Management (BOEM) Commercial Lease of Submerged Lands for Renewable Energy Development on the Outer Continental Shelf (OCS) Lease Areas (OCS-A 0534 and OCS-A 0561) and the southwest (SW) portion of Lease Area OCS-A 0501 (collectively referred to as the Lease Area), and along an export cable routes to sea-to-shore transition points (collectively, the Project Area), over the course of 5 years (March 27, 2025, through March 26, 2030). The proposed rule for this action concerned only Lease Areas OCS-A 0534 and the SW portion of Lease Area OCS-A 0501. However, after publication of the proposed rule, Lease Area OCS-A 0534 was segregated into two portions: OCS-A 0534 and OCS-A 0561. Phase 1 remained with Park City Wind (OCS-A 0534) while phase 2 (OCS-A 0561) was assigned to a sister company named Commonwealth Wind, LLC (subsidiary of Avangrid). As a result of this, Park City Wind requested that the Letter of Authorization (LOA), if issued, be issued to Avangrid, who would oversee the construction of the both phases of the Project by its two subsidiaries. These regulations, which allow for the issuance of a LOA for the incidental take of marine mammals during construction-related activities within the Project Area during the effective dates of the regulations, prescribe the permissible methods of taking and other means of effecting the least practicable adverse impact on marine mammal species or stocks and their habitat as well as requirements pertaining to the monitoring and reporting of such taking.

DATES:

This rule is effective from March 27, 2025, through March 26, 2030.

FOR FURTHER INFORMATION CONTACT:

Karolyn Lock, Office of Protected Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION:

Availability

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

Purpose and Need for Regulatory Action

This final rule, as promulgated, provides a framework under the authority of the MMPA (16 U.S.C. 1361 et seq.) for NMFS to authorize the take of marine mammals incidental to construction of the Project within the Project Area. NMFS received a request from the applicant to incidentally take a small number of marine mammals from 39 species of marine mammals. After reviewing the request and making the required findings, NMFS could authorize the take, by harassment only, of 38 species, representing 38 stocks (19 species by Level A harassment and all 38 species by Level B harassment) incidental to the applicant's 5 years of construction activities. The applicant did not request and NMFS neither anticipates nor allows take by serious injury or mortality incidental to the specified activities in this final rulemaking.

Legal Authority for the Final 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 (when applicable), 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, the applicant did not request and NMFS neither anticipates nor would allow take by serious injury or mortality incidental to the specified activities in this final rulemaking. Relevant definitions of MMPA statutory and regulatory terms are included below:

• Citizen —individual U.S. citizens or any corporation or similar entity if it is organized under the laws of the United States or any governmental unit defined in 16 U.S.C. 1362(13) (50 CFR 216.103);
• Take —to harass, hunt, capture, or kill, or attempt to harass, hunt, capture, or kill any marine mammal (16 U.S.C. 1362);
• Incidental Harassment, Incidental Taking and Incidental, but not Intentional, Taking —an accidental taking. This does not mean that the taking is unexpected, but rather it includes those takings that are infrequent, unavoidable or accidental (50 CFR 216.103);
• Serious Injury —any injury that will likely result in mortality (50 CFR 216.3);
• Level A harassment —any act of pursuit, torment, or annoyance which has the potential to injure a marine mammal or marine mammal stock in the wild (16 U.S.C. 1362; 50 CFR 216.3); and
• Level B harassment —any act of pursuit, torment, or annoyance which has the potential to disturb a marine mammal or marine mammal stock in the wild by causing disruption of behavioral patterns, including, but not limited to, migration, breathing, nursing, breeding, feeding, or sheltering (16 U.S.C. 1362).

Section 101(a)(5)(A) of the MMPA and the implementing regulations at 50 CFR part 216, subpart I, provide the legal basis for proposing and, if appropriate, issuing this rule containing 5-year regulations and associated LOA. This final rule also establishes required mitigation, monitoring, and reporting requirements for the in-water specified activities.

Summary of Major Provisions Within the Final Rule

The major provisions within this final rule include:

• Allowing NMFS to authorize, under a LOA, the take of small numbers of marine mammals by Level A harassment and/or Level B harassment (50 CFR 217.322) incidental to the Project and prohibiting take of such species or stocks in any manner not permitted (50 CFR 217.323) ( e.g., mortality or serious injury);
• Establishing a seasonal moratorium on impact pile driving and drilling during January 1 through April 30, annually, as well as avoiding impact pile driving and drilling in December in order to minimize impacts to North Atlantic right whales (Eubalaena glacialis). Impact pile driving and drilling must not be planned in December; however, it may then only occur if necessary to complete the Project within a given year and with prior approval by NMFS ( e.g., as a result of unforeseen circumstances such as unanticipated weather delays, unexpected technical difficulties). LOA Holder must notify NMFS in writing by September 1 of that year that pile driving or drilling cannot be avoided and circumstances are expected to necessitate pile driving or drilling in December;
• Establishing a seasonal moratorium on vibratory pile driving (i.e., vibratory setting of piles) during December 1 through May 31, annually, to minimize impacts to North Atlantic right whales ( Eubalaena glacialis);
• Establishing a seasonal moratorium on the detonation of unexploded ordnance or munitions and explosives of concern (UXO/MEC) from December 1 through May 31, annually. UXO/MEC detonation must not be planned for December or May in order to minimize impacts to North Atlantic right whales (Eubalaena glacialis); however, UXO/MEC detonation may occur in December or May with NMFS' approval on a case-by-case basis only.
• Requirements for UXO/MEC detonations to only occur if all other means of removal are impracticable (i.e., As Low As Reasonably Practicable (ALARP) risk mitigation procedure)), conducting UXO/MEC detonations during daylight hours only, and limiting detonations to one per 24 hour period;
• Conducting both visual and passive acoustic monitoring (PAM) by trained, NMFS-approved Protected Species Observers (PSOs) and PAM operators before, during, and after select in-water construction activities;
• Establishing clearance and shutdown zones for all in-water construction activities to prevent or reduce the risk of Level A harassment and to minimize the risk of Level B harassment, including a delay or shutdown of foundation impact pile driving and delay to UXO/MEC detonation if a North Atlantic right whale is observed at any distance by PSOs or acoustically detected within certain distances;
• Establishing minimum visibility and PAM monitoring zones during foundation installation activities (i.e., impact pile driving, vibratory pile driving, and drilling);
• Requiring use of at least two noise attenuation devices during all foundation installation activities and UXO/MEC detonations to reduce noise levels to those modeled assuming a broadband 10 decibel (dB) attenuation;
• Requiring sound field verification (SFV) requirements during foundation installation and UXO/MEC detonations to measure in situ noise levels for comparison against the modeled results.
• Requiring SFV during the operational phase of the Project;
• Requiring soft-start during impact pile driving and ramp-up during the use of high-resolution geophysical (HRG) marine site characterization survey equipment;
• Requiring various vessel strike avoidance measures;
• Requiring various measures during fisheries monitoring surveys, such as removing gear from the water if marine mammals are considered at-risk or are interacting with gear;
• Requiring regular and situational reporting including, but not limited to, information regarding activities occurring, marine mammal observations and acoustic detections, and sound field verification monitoring results; and
• Requiring monitoring of the North Atlantic right whale sighting networks, Channel 16, and PAM data, as well as reporting any sightings to the NMFS or sighting network.

Through adaptive management, as described in the provisions established in these regulations, NMFS Office of Protected Resources may modify ( e.g., delete, 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 or the authorized take is having, or may have, more than a negligible impact on the concerned species or stock (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)).

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

This project is covered under title 41 of the Fixing America's Surface Transportation Act, or “FAST-41.” FAST-41 includes a suite of provisions designed to expedite the environmental review for covered infrastructure projects, including enhanced interagency coordination as well as milestone tracking on the public-facing Permitting Dashboard. FAST-41 also places a 2-year limitations period on any judicial claim that challenges the validity of a Federal agency decision to issue or deny an authorization for a FAST-41 covered project (42 U.S.C. 4370m-6(a)(1)(A)).

The Project is listed on the Permitting Dashboard, where milestones and schedules related to the environmental review and permitting for the Project can be found at https://www.permits.performance.gov/permitting-project/new-england-wind.

Summary of Request

On December 1, 2021, the original applicant, Park City Wind, a limited liability company registered in the State of Delaware and wholly owned subsidiary of Avangrid submitted a request for the promulgation of regulations and issuance of an associated 5-year LOA to take, by harassment only, marine mammals incidental to construction activities associated with implementation of the New England Wind Project (hereafter “Project”) offshore of Massachusetts in the BOEM Lease Area OCS-A 0534 and the possible use of the SW portion of Lease Area OCS-A 0501. The request was for the incidental, but not intentional, taking of a small number of 39 marine mammal species by Level B harassment (for all species or stocks) and by Level A harassment (for 19 species or stocks). Park City Wind did not request, and NMFS neither expects nor would allow under this rule, take by serious injury or mortality to occur for any marine mammal species or stock incidental to the specified activities.

In response to our questions and comments, and following extensive information exchange between Park City Wind and NMFS, the applicant submitted a final revised application on July 13, 2022. NMFS deemed it adequate and complete on July 20, 2022. This final application is available on NMFS' website at https://www.fisheries.noaa.gov/protected-resource-regulations.

On August 22, 2022, NMFS published a notice of receipt (NOR) of the adequate and complete application in the Federal Register (87 FR 51345), requesting public comments and information during a 30-day public comment period. During the NOR public comment period, NMFS received comment letters from one private citizen and one non-governmental organization (ALLCO Renewable Energy Limited). NMFS reviewed all submitted material and took the material into consideration during the drafting of the proposed rule.

In January 2023 and again in March 2023, Park City Wind submitted memos to NMFS detailing updates and changes to their ITA application (“Update Application”). These memos updated the density models using the 2022 Roberts et al. density models, project foundation installation and potential UXO/MEC detonation schedules, vibratory pile driving ( i.e., vibratory setting of piles) assessment, and mitigation of drilling activity. In addition, the applicant detailed development of their fisheries monitoring program and associated mitigation measures. In a May 2023 memo, Park City Wind submitted corrected take estimate amounts for foundation installation activities and total take requested across all activities. These updates were reflected in the proposed rule. These memos are available on the NMFS website at https://www.fisheries.noaa.gov/action/incidental-take-authorization-park-city-wind-llc-construction-new-england-wind-offshore-wind.

On June 8, 2023, NMFS published a proposed rule for the Project in the Federal Register (88 FR 37606). In the proposed rule, NMFS synthesized all of the information provided by the applicant, all best available scientific information and literature relevant to the proposed project, made preliminary small numbers and negligible impact determinations, and outlined, in detail, proposed mitigation designed to effect the least practicable adverse impacts on marine mammal species and stocks, as well as proposed monitoring and reporting measures. The public comment period on the proposed rule was open for 30 days from June 8, 2023 through July 10, 2023. A summary of public comments received during this 30-day period are described in the Comments and Responses section. The public comments are available to be viewed on the Federal e-Rulemaking Portal at https://www.regulations.gov.

In January 2024, Park City Wind submitted a final draft of the new modeling and associated acoustic ranges, exposure estimates, and take estimates. Within these memos, the applicant revised the model(s) used and model assumptions for foundation installation activities and updated the acoustic ranges, exposure ranges, exposure estimates, take estimates, and amount of requested take as a result. The model changes are detailed in the Modeling and Take Estimates section in this final rule. NMFS accepted the updated modeling and has reflected the changes to the distance to thresholds, exposure estimates, and take estimates within the final rule. A description of these changes can be found below in the Modeling and Take Estimates section. This January 2024 Application Update is on NMFS website at https://www.fisheries.noaa.gov/action/incidental-take-authorization-park-city-wind-llc-construction-new-england-wind-offshore-wind.

On May 6, 2024, Park City Wind notified NMFS that it had requested that BOEM segregate a portion of lease area OCS-A-0534, which would then be assigned to another subsidiary of Avangrid, Commonwealth Wind, LLC, as lease area OCS-A 0561. Park City Wind requested to NMFS that the incidental take regulation (ITR) governing take of marine mammals incidental to activities associated with both phases of the Project and the associated LOA (if issued by NMFS) be issued to Park City Wind's parent company, Avangrid, a limited liability company registered in the State of Oregon, who would oversee phase 1 (constructed and operated by Park City Wind) and phase 2 (constructed and operated by Commonwealth Wind) of the New England Wind Project. The lease segregation, completed by BOEM on May 15, 2024, did not alter the geographic location or size of the area in which the project would be built, nor did the applicant request any changes to the construction schedule, planned activities, or take. In short, no substantive changes to the Project were requested. As a result, where appropriate, Avangrid, owner of Park City Wind, has henceforth been incorporated as the applicant or LOA Holder throughout this final rule.

NMFS previously issued one Incidental Harassment Authorization (IHA) to Park City Wind for the taking of small numbers of marine mammals incidental to marine site characterization surveys, using HRG of the Project's phase 1 (Park City Wind) in the BOEM Lease Area OCS-A 0534 (87 FR 44087, July 7, 2022); phase 2 was not part of this authorization (Commonwealth Wind). However, no work occurred under this initial IHA and Park City Wind requested a reissuance of the IHA with new effective dates. NMFS reissued the IHA (88 FR 88892, December 26, 2023) with the new effective dates of March 1, 2024, through February 28, 2025. NMFS has also previously issued an IHA to Avangrid, owner of Park City Wind, LLC, to take small numbers of marine mammals incidental to HRG surveys in BOEM Lease Area (OCS-A 0508) off the coasts of North Carolina and Virginia (84 FR 31032, June 28, 2019). To date, Park City Wind and Avangrid have complied with all IHA requirements ( e.g., mitigation, monitoring, and reporting). Applicable monitoring results may be found in the Estimated Take of Marine Mammals section. If available, the full monitoring reports can be found on NMFS' website at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable.

On August 1, 2022, NMFS announced proposed changes to the existing North Atlantic right whale vessel speed regulations (87 FR 46921, August 1, 2022) to further reduce the likelihood of mortalities and serious injuries to endangered right whales from vessel collisions, which are a leading cause of the species' decline and a primary factor in an ongoing Unusual Mortality Event (UME). Should a final vessel speed rule be issued and become effective during the effective period of this ITR—or any other MMPA incidental take authorization (ITA)—the authorization holder will be required to comply with any and all applicable requirements contained within the final rule. Specifically, where measures in any final vessel speed rule are more protective or restrictive than those in this or any other MMPA authorization, authorization holders will be required to comply with the requirements of the rule. Alternatively, where measures in this or any other MMPA authorization are more restrictive or protective than those in any final vessel speed rule, the measures in the MMPA authorization will remain in place. The responsibility to comply with the applicable requirements of any vessel speed rule will become effective immediately upon the effective date of any final vessel speed rule and, when notice is published on the effective date, NMFS will also notify Avangrid if the measures in the speed rule were to supersede any of the measures in the MMPA authorization such that they were no longer required.

Description of the Specified Activity

Overview

Avangrid plans to construct and operate two offshore wind projects within OCS-A 0534 and OCS-A 0561: Park City Wind (phase 1, 0534) and Commonwealth Wind (phase 2, 0561) (collectively called New England Wind; hereinafter referred to as “Project”). The Project will occupy all of Lease Area OCS-A 0534, OCS-A 0561, and potentially a portion of Lease Area OCS-A 0501 in the event that Vineyard Wind 1 does not develop spare or extra positions included in Lease Area OCS-A 0501. If Vineyard Wind 1 does not develop spare or extra positions in Lease Area OCS-A 0501, those positions would be assigned to Lease Area OCS-A 0534.

The Project will consist of several different types of permanent offshore infrastructure, including wind turbine generators (WTGs) and associated foundations, electrical service platforms (ESPs) and their foundations, inter-array cables, offshore export cables, and scour protection. Specifically, activities to construct the Project include the installation of 41-62 WTGs and 1-2 ESPs in phase 1 by impact and vibratory pile driving and, in the event of an obstruction, drilling. Phase 2 depends upon the final footprint of phase 1. Phase 2 is expected to include the installation of 64-88 WTGs and 1-3 ESP positions by impact and vibratory pile driving and, in the event of an obstruction, drilling. In total, up to 129 WTGs and 2-5 ESPs may be constructed at a maximum of 130 positions (2 positions may potentially have co-located ESPs ( i.e., two foundations installed at one grid position), resulting in 132 foundations). Additional activities will include cable installation, site preparation activities ( e.g., dredging), HRG surveys, the potential detonations of up to 10 UXO/MEC, and conducting several types of fishery and ecological monitoring surveys. Multiple vessels will transit within the Project Area and between ports and the wind farm to perform the work and transport crew, supplies, and materials. All offshore cables will connect to onshore export cables, substations, and grid connections in Barnstable County, Massachusetts. Marine mammals exposed to elevated noise levels during pile driving, drilling, UXO/MEC detonations, or site characterization surveys may be taken by Level A harassment and/or Level B harassment, depending on the specified activity. A detailed description of the construction project is provided in the proposed rule as published in the Federal Register (88 FR 37606, June 8, 2023).

Dates and Duration

Avangrid anticipates activities resulting in harassment to marine mammals occurring throughout all 5 years of the final rule (table 1). Offshore Project activities are expected to begin in March 2025, after issuance of the 5-year LOA, and continue through March 2030. Avangrid anticipates the following construction schedule over the 5-year period. Avangrid has noted that these are the best and conservative estimates for activity durations, but that the schedule may shift due to weather, mechanical, or other related delays. Additional information on dates and activity-specific durations can be found in the proposed rule and are not repeated here.

Specified Geographical Region

A detailed description of the Specified Geographical Region, identified as the Mid-Atlantic Bight, is provided in the proposed rule (88 FR 37606, June 8, 2023). Since the proposed rule was published, no changes have been made to the Specified Geographical Region. This final rule provides clarity on the boundaries of the Mid-Atlantic Bight, which spans from Cape Hatteras, North Carolina to Cape Cod, Massachusetts and extends into the western Atlantic to the 100-m isobath. All of Avangrid's specified activities ( i.e., pile driving and drilling of WTG and ESP foundations; number of possible UXO/MEC detonations ( n =10); placement of scour protection; trenching, laying, and burial activities associated with the installation of the export cable route and inter-array cables; HRG site characterization surveys; and WTG operation) are concentrated in the Lease Area and cable corridor offshore Massachusetts. Avangrid would also concentrate vessel use within this area; however, some limited vessel movement may occur outside this area.

Comments and Responses

NMFS published a proposed rule in the Federal Register on June 8, 2023 (88 FR 37606) for a 30-day public comment period. The proposed rule described, in detail, the specified activities, the specified geographical region of the specified activities, the marine mammal species that may be affected by these activities, and the anticipated effects on marine mammals. In the proposed rule, we requested that interested persons submit relevant information, suggestions, and comments on Park City Wind's (now Avangrid's) request for the promulgation of regulations and issuance of an associated LOA described therein, our estimated take analyses, the preliminary determinations, and the proposed regulations.

NMFS received 41 comment submissions, including comments from the Marine Mammal Commission (Commission), several non-governmental organizations, and private citizens, all of which are available for review on https://www.regulations.gov. Some of these comments were out-of-scope or not applicable to the Project ( e.g., general opposition to or support of offshore wind projects, concerns for other species outside NMFS' jurisdiction) and are not described herein or discussed further. Non-governmental organizations included: Long Island Commercial Fishing Association, Responsible Offshore Development Alliance, and Green Oceans. These letters, and the Commission's, contained substantive information that NMFS considered in this final rule, including comments related to the estimated take analysis, final determinations, and final mitigation, monitoring, and reporting requirements. A summary of comments are described below, along with NMFS' responses.

Modeling and Take Estimates

Comment 1: The Commission has stated that, due to uncertainty in how NMFS will be addressing their previously submitted comments for other final offshore wind rulemakings, they are not providing “an exhaustive letter regarding similar issues” for the proposed action. They have stated that, in lieu of this, they incorporate by reference all previously submitted comment letters for past proposed rules ( i.e., Empire Wind, Dominion Energy Virginia, Sunrise Wind, Revolution Wind, Ocean Wind 1, South Fork Wind) and that NMFS should specifically review these previously submitted letters ( e.g., Sunrise Wind (88 FR 8996, February 10, 2023), Revolution Wind (87 FR 79072, December 23, 2022), and Ocean Wind 1 (87 FR 64868, October 26, 2022) and incorporate, where applicable, relevant information in the context of the Project. They specifically noted that these general concerns could include “underestimated numbers of Level A and B harassment takes (including failing to round up to group size), incomplete SFV measurement requirements, insufficient mitigation and monitoring measures, errors and omissions in the preamble to and the proposed rule, and the general issue of quality control and quality assurance in NMFS's preparation of proposed incidental take authorizations.”

Response: NMFS acknowledges the receipt of a comment letter on the proposed Project by the Commission, as well as receipt of comment letters from the Commission for the other referenced proposed projects. We appreciate that, in the past, the Commission has provided very specific and detailed comments and suggestions on NMFS' actions, as a collaborative effort to improve both the ITAs themselves as well as the conservation benefits for NMFS' trust species. Because the Commission did not provide specific comments on the proposed rule for the Project, we cannot address any specific concerns. However, we can address general themes of concern raised in previous letters, and, inasmuch as another specific comment is applicable here, we refer the Commission back to our previous responses.

Overall, the Commission's letters raised concerns over concern underestimated Level A and B harassment zones and numbers of takes, incomplete SFV measurement requirements, insufficient mitigation and monitoring measures, errors and omissions in the proposed rule and its preamble, and the general issue of quality control and quality assurance in NMFS's preparation of proposed ITAs. With respect to mitigation, monitoring and reporting requirements, we have thoroughly addressed the Commission's previous concerns and have updated final rules, including this one, accordingly. Lastly, any “omissions” and “general issues of quality control and quality assurance” from one action are less likely to be present in another action as updates are carried through across actions (although NMFS does not agree that every example previously raised by the Commission was, in fact, an error).

Comment 2: Commenters recommend NMFS re-estimate and authorize Level A harassment takes based on modeling results for the worst-case scenario rather than presuming an arbitrary 80- or 100-percent reduction for mitigation efficacy and/or a 10-dB sound attenuation for impact pile driving, re-estimate and authorize Level B harassment takes based on more conservative assumptions for the pile-driving scenarios that could occur (including only one monopile or fewer than four pin piles installed per day), re-estimate the various mortality, Level A harassment, and Level B harassment zones and numbers of takes based on 0 dB of sound attenuation for UXO/MEC detonations and authorize Level A and B harassment takes, including behavior takes, that could result from UXO/MEC detonations, and increase any Level A or B harassment takes to mean group size (including updates that reflect the results of more recent marine mammal surveys in the Rhode Island-Massachusetts WEA). Other commenters had similar comments. Commenter(s) also suggested that the numbers of takes, particularly with respect to the North Atlantic right whale, rely on mitigation methods that remain unproven.

Response: NMFS disagrees that our analysis should carry forward take estimates based on the worst-case scenario that assumes no reduction of impacts results from the mitigation and notes that the commenter did not present any data supporting their recommendation. As described in the proposed rule, this final rule reasonably assumes that the mitigation efforts will be effective at reducing the potential for Level A harassment calculated in the density-based models. The models do not account for mitigation (except with respect to assuming attenuation and seasonal restrictions) and, therefore, it is reasonable to assume the model overestimates Level A harassment. Further, while the scientific literature documents marine mammals are likely to avoid loud noises such as pile driving ( e.g., Brandt et al., 2016, Nowack et al., 2004), avoidance was not quantitatively considered in the take estimates (although NMFS reasonably predicts this natural behavior will further reduce the potential for Level A harassment).

In the proposed rule, NMFS described the best available science, which supports the assumption that at least 10 dB of attenuation can be reliably achieved using noise attenuation systems such as a double bubble curtain. The commenter did not provide reason for why they believe this was an overestimate nor did they suggest an alternative amount of attenuation NMFS should consider other than zero attenuation. Other commenters expressed similar support stating that bubble curtains are not effective for low-frequency cetaceans. NMFS agrees that attenuation levels vary by frequency band and that bubble curtains attenuate higher frequency sounds more effectively; however, NMFS disagrees that lower frequency bands, which are important to consider when evaluating impacts, are not attenuated at all. The data from Bellmann (2021), shows that for both single and double bubble curtains, more than 10 dB of attenuation was achieved for bands as low as 32 Hz. And while it is true that performance diminishes significantly at lower frequencies (<32 Hz), those bands also contain significantly less pile driving sound and is 16+ dB outside the most susceptible frequency range for low-frequency cetaceans.

NMFS recognizes that the key to effective mitigation is the ability to detect marine mammals to trigger such mitigation. Avangrid is required to undertake extensive monitoring to maximize marine mammal detection effectiveness. The reduction to the density-based take estimate appropriately reflects and acknowledges the monitoring efforts, including the placement of three PSOs on the pile driving platform and dedicated PSOs vessel(s) and PAM.

NMFS agrees that there is potential for behavioral disturbance from a single detonation per day and disagrees that “behavior takes” were omitted and have not been accounted for. However, the behavioral threshold for underwater detonations identified by the Commission (5 dB less than the temporary threshold shift (TTS) is only applicable to multiple detonations per day. NMFS is not aware of evidence to support the assertion that animals will have behavioral responses that would qualify as take to temporally and spatially isolated explosions at received levels below the TTS threshold. Accordingly, the current take estimate framework allows for the consideration of behavioral disturbance resulting from single explosions specifically if they are exposed above the TTS threshold, as opposed to the 5-dB lower threshold for behavioral disturbance from multiple detonations. We acknowledge in our analysis that individuals exposed above the TTS threshold may also be harassed by direct behavioral, disruption and those potential impacts are considered in the negligible impact determination. The distances to harassment thresholds have not changed from the application and proposed rule and are presented in this final rule. Take estimates did not change as a result of including this additional information.

Comment 3: Commenter(s) claimed that NMFS thresholds are outdated, primarily because scientific literature demonstrates examples where behavioral disturbances have been documented where received levels are lower than 160 dB. Moreover, the commenter suggested that estimating the extent of Level B take from impact driving using the 160dB (impulsive) threshold is flawed because an animal may be exposed to several hours of pile driving per day which should be considered continuous and that, although impulsive at the source, the sound from impact driving may be received as a continuous source at a distance. Commenter(s) stated that vessel noise is not included in the effects and that it should be included in calculations for harassment zones (as a continuous noise source) and as a source of take. For these reasons, commenter(s) suggested the proposed rule underestimates the takes by Level B harassment and “zones of impact”; thus NMFS' small numbers and negligible impact determination is flawed.

Response: For the reasons described below, NMFS disagrees that the 160-dB threshold for behavioral harassment is not supported by the best available science and that the small numbers and negligible impact determinations are flawed based on the use of this threshold in the take estimate analysis. The potential for behavioral response to an anthropogenic source can be highly variable and context-specific (Ellison et al., 2012). While NMFS acknowledges the potential for Level B harassment at exposures to received levels below 160 dB rms, it should also be acknowledged that not every animal exposed to received levels above 160 dB rms will respond in ways constituting behavioral harassment. There are a variety of studies indicating that contextual variables play a very important role in response to anthropogenic noise, and the severity of effects are not necessarily linear when compared to a received level (RL). Several studies ( e.g., Nowacek et al., 2004 and Kastelein et al., 2012 and 2015) showed there were behavioral responses to sources below the 160 dB threshold but also acknowledged the importance of context in these responses. For example, Nowacek et al. (2004) reported the behavior of five out of six North Atlantic right whales was disrupted at RLs of only 133-148 dB re 1 μPa (returning to normal behavior within minutes) when exposed to an alert signal. However, the authors also reported that none of the whales responded to noise from transiting vessels or playbacks of ship noise even though the RLs were at least as loud and contained similar frequencies to those of the alert signal. The authors state that a possible explanation for whales responding to the alert signal and not responding to vessel noise is due to the whales having been habituated to vessel noise while the alert signal was a novel sound. In addition, the authors noted differences between the characteristics of the vessel noise and alert signal, which may also have played a part in the differences in responses to the two noise types. Therefore, it was concluded that the signal itself, as opposed to the RL, was responsible for the response. DeRuiter et al. (2012) also indicate that variability of responses to acoustic stimuli depends not only on the species receiving the sound and the sound source, but also on the social, behavioral, or environmental contexts of exposure. Finally, behavioral responses depend on many contextual factors, including range to source, RL above background noise, novelty of the signal, and differences in behavioral state (Ellison et al., 2012, Gong et al., 2014). Similarly, Kastelein et al. (2015) examined behavioral responses of a harbor porpoise to sonar signals in a quiet pool but stated behavioral responses of harbor porpoises at sea would vary with context such as social situation, sound propagation, and background noise levels.

NMFS uses 160 dB (rms) as the received sound pressure level for estimating the onset of Level B behavioral harassment takes for impulsive/intermittent sound sources, and this is currently considered the best available science while acknowledging that the 160 dB_rms step-function approach is a simplistic approach. While it may be true because of reverberation that impulsive pile driving strikes may “stretch” as their sound travels through the environment, we do not classify these sounds as continuous, like drilling and vibratory pile driving. NMFS' behavioral harassment thresholds consider instantaneous exposure to noise and are based on a received level. These thresholds do not account for duration of exposure, as our PTS onset thresholds do. Thus, whether an individual was exposed to a few pile driving strikes or exposed for several hours of pile driving, the 160-dB threshold would still apply. While it is correct that in practice it works as a step-function ( i.e., animals exposed to received levels above the threshold are considered to be “taken” and those exposed to levels below the threshold are not), it is in fact intended as a sort of mid-point of likely behavioral responses, which are extremely complex depending on many factors including species, noise source, individual experience, and behavioral context. What this means is that, conceptually, the function recognizes that some animals exposed to levels below the threshold will in fact react in ways that appropriately considered take while others that are exposed to levels above the threshold will not. Use of the 160-dB threshold allows for a simplistic quantitative estimate of take while we can qualitatively address the variation in responses across different received levels in our discussion and analysis.

Overall, we reiterate the lack of scientific consensus regarding what criteria might be more appropriate. Defining sound levels that disrupt behavioral patterns is difficult because responses depend on the context in which the animal receives the sound, including an animal's behavioral mode when it hears sounds ( e.g., feeding, resting, or migrating), prior experience, and biological factors ( e.g., age and sex). Other contextual factors, such as signal characteristics, distance from the source, and signal to noise ratio, may also help determine response to a given received level of sound. Therefore, levels at which responses occur are not necessarily consistent and can be difficult to predict (Southall et al., 2007; Ellison et al., 2012; Southall et al., 2021). For example, Gomez et al. (2016) reported that RL was not an appropriate indicator of behavioral response. Further, the seminal reviews presented by Southall et al. (2007), Gomez et al. (2016), and Southall et al. (2021) did not suggest any specific new criteria due to lack of convergence in the data. Undertaking a process to derive defensible exposure-response relationships, as suggested by Tyack and Thomas (2019), is complex. The recent systematic review by Gomez et al. (2016) was unable to derive criteria expressing these types of exposure-response relationships based on currently available data.

NMFS acknowledges that there may be methods of assessing likely behavioral responses to acoustic stimuli that better capture the variation and context-dependency of those responses than the simple 160 dB step-function used here; there is no agreement on what that method should be or how more complicated methods may be implemented by applicants. NMFS is committed to continuing its work in developing updated guidance with regard to acoustic thresholds but pending additional consideration and process, is reliant upon an established threshold that is reasonably reflective of best available science.

NMFS disagrees that vessel noise would result in take and, therefore, be necessary to include in the take calculations in this final rule. Vessels produce low-frequency noise, primarily through propeller cavitation, with main energy in the 5-300 hertz (Hz) frequency range. Source levels range from about 140 to 195 decibels (dB) referenced to 1 (re 1) μPa (micropascal) at 1 m (National Research Council (NRC), 2003; Hildebrand, 2009), depending on factors such as vessel type, load, and speed, and vessel hull and propeller design. Studies of vessel noise show that it appears to increase background noise levels in the 71-224 Hz range by 10-13 dB (Hatch et al., 2012; McKenna et al., 2012; Rolland et al., 2012). As discussed in the Negligible Impact Analysis and Determination section (specifically the Auditory Masking or Communication Impairment section) of both the proposed and final rule, the level of masking that could occur from the specified activities will have a negligible impact on marine mammals, including North Atlantic right whales. Inherent in the concept of masking is the fact that the potential for the effect is only present during the times that the animal and the sound source are in close enough proximity for the effect to occur. In addition, this time period would need to coincide with a time that the animal was utilizing sounds at the masked frequency). As our analysis (both quantitative and qualitative components) indicates, because of the relative movement of whales and vessels, as well as the stationary nature of a majority of the activities, we do not expect these exposures with the potential for masking to be of a long duration within a given day. Further, because of the relatively low density of North Atlantic right whales during months when most of project activities would be occurring ( i.e., May through November in most cases), and the relatively large area over which the vessels will travel and where the activities will occur, we do not expect any individual North Atlantic right whales to be exposed to potentially masking levels from these surveys for more than a few days in a year. Furthermore, as many of the activities are occurring in clusters and specific areas rather than sporadically dispersed in the Project Area ( i.e., foundation installation all occurs in the same general area, nearshore cable installation activities occur in relatively similar and nearby areas), animals are likely to temporarily avoid these locations during periods where activities are occurring but are expected to return once activities have ceased.

As noted above, any masking effects of the project's activities are expected to be limited in duration, if present. For HRG surveys, given the likelihood of significantly reduced received levels beyond short distances from the transiting survey vessel, the short duration of potential exposure, the lower likelihood of extensive additional contributors to background noise offshore and within these short exposure periods, and the fact that the frequency of HRG signals are primarily above those used in social communication or for detection of other important clues, we believe that the incremental addition of the survey vessel is unlikely to result in more than minor and short-term masking effects. For pile driving and drilling, and especially foundation installation, masking effects are more likely given the larger zones and longer durations, and animals that approach the source could experience temporary masking of some lower frequency cues. However, any such effects would be localized to the areas around these stationary activities, which means that whales transiting through the area could adjust their transit away from the construction location and return once the activity has completed. As described in the “Potential Effects of the Activities on Marine Mammals” section of the proposed rule, NMFS acknowledges the noise contributions of vessels to the soundscape and the potential for larger vessels such as commercial shipping vessels, especially, to mask mysticete communication. For the activity as a whole, including the operation of supporting vessels for Avangrid's activities, any masking that might potentially occur would likely be incurred by the same animals predicted to be exposed above the behavioral harassment threshold, and thereby accounted for in the analysis. NMFS notes that the commenter did not provide additional scientific information for NMFS to consider to support its concern.

Comment 4: Commenter(s) recommended that NMFS should consider the best available data regarding North Atlantic right whale abundance in the project area, as well as the most comprehensive models for estimating marine mammal take and developing robust mitigation measures.

Response: The MMPA and its implementing regulations require that ITRs be established based on the best scientific evidence available. NMFS generally considers the information in the most recent U.S. Atlantic and Gulf of Mexico Marine Mammal Stock Assessments Report (SAR; Hayes et al., 2023) to be the best scientific evidence available for a particular marine mammal stock because of the MMPA's rigorous SAR procedural requirements, which includes peer review by a statutorily established Scientific Review Group. Since publication of the proposed rule, NMFS has released the draft 2023 Stock Assessment Report indicating the North Atlantic right whale population abundance is estimated as 340 individuals based on sighting data through December 31, 2021 (89 FR 5495, January 29, 2024). NMFS has used the best scientific evidence available in the analysis of this final rule. This new stock abundance estimate, which is based on the analysis from Pace et al. (2017) and subsequent refinements found in Pace (2021), provides the best scientific evidence available, and in this case, the most recent estimate, including improvements to NMFS's right whale abundance model. NMFS notes this estimate aligns with the 2022 North Atlantic Right Whale Report Card (Pettis et al., 2022) estimate (also 340) based on sighting data through August 2022 but, as described above, the SARs are peer reviewed by other scientific review groups prior to being finalized and published and the Report Card is published independently by Consortium members without undertaking this peer review process. Based on this, NMFS has considered all relevant information regarding North Atlantic right whale, including the information cited by the commenters. However, NMFS has relied on the draft 2023 SAR in this final rule as it reflects the best scientific evidence available.

We further note that this change in abundance estimate does not change the estimated take of North Atlantic right whales or authorized take numbers, nor affect our ability to make the required findings under the MMPA for Avangrid's construction activities.

NMFS evaluates the models used by applicants to support take estimates to ensure that they are methodologically sound and incorporate the best science available. NMFS also requires use of the Roberts et al. (2016, 2023) density data and SARs abundance estimates for all species, both of which represent the best scientific evidence available regarding marine mammal occurrence.

Comment 5: Commenter(s) stated that Level A harassment in the form of a Permanent Threshold Shift (PTS) would result in deafness and lead to mortality. It was also asserted that Level B harassment in the form of a TTS is temporary deafness which could result in an increased risk of vessel strike. Lastly, that NMFS has refused to acknowledge the lack of available data on low frequency cetacean hearing or potential behavioral impacts from noise on low frequency cetacean species.

Response: Neither the proposed rule or this final rule allow mortality or serious injury of marine mammals to be authorized. The best scientific evidence available indicates that the anticipated impacts from the specified activities potentially include avoidance, cessation of foraging or communication, TTS and PTS, stress, masking, etc. (as described in the Effects of the Specified Activities on Marine Mammals and their Habitat section in the proposed rule). NMFS defines a threshold shift 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 (PTS), 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). 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 or deafness as it is a temporary form of hearing impairment. Repeated sound exposure that leads to TTS could cause PTS. For this project, as stated in the proposed rule, no more than a small degree of PTS is expected to be associated with any of the incurred Level A harassment, given it is unlikely that animals would stay in the close vicinity of a source for a duration long enough to produce more than a small degree of PTS. PTS would consist of minor degradation of hearing capabilities occurring predominantly at frequencies one-half to one octave above the frequency of the energy produced by pile driving or instantaneous UXO/MEC detonation ( i.e., the low-frequency region below 2 kHz) (Cody and Johnstone, 1981; McFadden, 1986; Finneran, 2015), not severe hearing impairment. If hearing impairment occurs from either impact pile driving or UXO/MEC detonation, it is most likely that the affected animal would lose a few decibels in its hearing sensitivity, which in most cases is not likely to meaningfully affect its ability to forage and communicate with conspecifics.

As stated in the proposed rule, NMFS acknowledges that there is limited data on threshold shifts in marine mammals. Relationships between TTS and PTS thresholds have not been studied in marine mammals, and there is no PTS data for cetaceans. However, such relationships are assumed to be similar to those in humans and other terrestrial mammals. Noise exposure can result in either a permanent shift in hearing thresholds from baseline (PTS; a 40 dB threshold shift approximates a PTS onset; e.g., Kryter et al., 1966; Miller, 1974; Henderson et al., 2008) or a temporary, recoverable shift in hearing that returns to baseline (a 6 dB threshold shift approximates a TTS onset; e.g., Southall et al., 2019). Based on data from terrestrial mammals, a precautionary assumption is that the PTS thresholds, expressed in the unweighted peak sound pressure level metric (PK), for impulsive sounds (such as impact pile driving pulses) are at least 6 dB higher than the TTS thresholds and the weighted PTS cumulative sound exposure level thresholds are 15 (impulsive sound) to 20 (non-impulsive sounds) dB higher than TTS cumulative sound exposure level thresholds (Southall et al., 2019a). Given the higher level of sound or longer exposure duration necessary to cause PTS as compared with TTS, PTS is less likely to occur as a result of these activities, but it is possible and a small amount has been proposed for authorization for several species. For more detailed information on PTS and TTS, please see the Hearing Threshold Shift and Negligible Impact Determination sections of the proposed rule.

NMFS disagrees that the potential effects to species as a result of the project's specified activities would result in increased risk of vessel strikes. Please see our response to Comment 8 for more details on the vessel strike avoidance requirements required by this final rule.

Comment 6: A commenter suggested that NMFS' low-frequency cetacean weighting function is inaccurate because it applies a 2-pole High-pass filter set at 200 Hz, while Southall et al. (2007) suggested moving the high-pass filter down to 7Hz. The commenter was also concerned that applying any weighting function underestimates the potential impacts on marine mammals because they claim applying a weighting function assumes that when hearing is less sensitive at the outer limits of the hearing range, the effects to the animal (potential for adverse impact) will be insignificant or non-existent unless inordinately loud. They also claimed that there is no empirical evidence that NMFS' weighting curve aligns with mysticetes infrasonic hearing. Further, they assert signal kurtosis was not accounted for in NMFS analysis and should be included in any predictive impact models. Commenter(s) also state that the spreading model is inadequate for modeling noise levels as it does not account for reflection off the water's surface or from other sources.

Response: The marine mammal weighting functions in NMFS' 2018 Revised Technical Guidance do not contain any filters. Furthermore, the Revised Technical Guidance provides generalized hearing ranges for marine mammal species, where the low-frequency cetacean lower bounds of the hearing range start at 7 kHz. These weighting functions are meant to reflect the hearing groups' susceptibility to noise-induced hearing loss and are based on audiogram data, as well as TTS data. Furthermore, for impulsive sources, there are peak sound pressure level criteria that are unweighted. Thus, impacts of noise on hearing will not be underestimated. For low-frequency cetaceans, since direct measurements of hearing ability are lacking, weighting functions are based on a multitude of information, including anatomical studies and modeling (Houser et al., 2001; Parks et al., 2007; Tubelli et al., 2012; Cranford and Krysl 2015); vocalizations (see reviews in Richardson et al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008); taxonomy; and behavioral responses to sound (Dahlheim and Ljungblad, 1990; see review in Reichmuth, 2007). Finally, kurtosis is an additional metric to determine if a sound is impulsive versus non-impulsive ( i.e., kurtosis is a measure of the “peakedness” of a noise waveform, with the impulsive components (Qiu et al., 2020). As described in the proposed rule and NMFS' Technical Guidance (NMFS, 2018), NMFS applies different thresholds in an impact analysis for impulsive and non-impulsive sources. Impact pile driving is categorized as an impulsive sound. Thus, while kurtosis was not assessed directly, whether a sound is impulsive or non-impulsive is inherently considered in our analyses when assessing the potential for PTS ( i.e., deciding which acoustic thresholds are appropriate based on sound source characteristics that include a source's impulsiveness). Therefore, kurtosis (the impulsivity of a sound source) is accounted for in NMFS analysis.

Potential impacts to marine mammal nervous systems through exposure to sound were discussed in the proposed rule in the Potential Effects of Underwater Sound on Marine Mammals section. NMFS assumes that the reference to “injury-causing” SPL by the commenter is the potential for a permanent threshold shift (PTS).

NMFS disagrees that the spreading model is inadequate. The degree to which underwater sound propagates away from a sound source is dependent on a variety of factors, which notably includes the frequency and directivity of the source, water depth (or bathymetry), the reflective or absorptive nature of the seabed, and other factors. Spherical spreading occurs in a perfectly unobstructed (free-field) environment not limited by depth or water surface, resulting in a 6-dB reduction in sound level for each doubling of distance from the source (20 × log[range]). Spherical spreading can be thought of as a `direct path' model, as all sound in the water column is assumed to have arrived via a direct path from the source. Cylindrical spreading occurs in an environment in which sound propagation is bounded by the water surface and sea bottom, resulting in a reduction of 3 dB in sound level for each doubling of distance from the source (10 × log[range]). Both cylindrical spreading and the often used `practical spreading' model are multi-path models, in that they account for sound which may consist of both direct paths and paths consisting of reflections from the seabed and the sea surface.

As described in the proposed rule, the area of water ensonified at or above the RMS 160-dB threshold was calculated using a simple model of sound propagation loss, which accounts for the loss of sound energy over increasing range. Our use of the spherical spreading model, is a reasonable approximation over the relatively short ranges involved. Even in conditions where cylindrical spreading (where propagation loss = 10 × log [range]; such that there would be a 3-dB reduction in sound level for each doubling of distance from the source) may be appropriate ( e.g., non-homogenous conditions where sound may be trapped between the surface and bottom), this effect does not begin at the source. Rather, spreading is typically more or less spherical from the source out to some distance, and then may transition to cylindrical (Richardson et al., 1995). Further, for these types of surveys, NMFS has determined that spherical spreading is a reasonable assumption even in relatively shallow waters, as the reflected energy from the seafloor will be much weaker than the more dominant, direct path energy. This is a result of the typically high-frequency and often downward directed nature of most HRG sources. Similar arguments, related to the validity of spherical spreading in shallow water for some HRG sources, have been made in literature (Ruppel et al., 2022), and NMFS has relied on this approach for past ITAs with similar equipment, locations, and depths. NMFS' User Spreadsheet tool assumes a “safe distance” methodology for mobile sources where propagation loss is spherical spreading (20LogR) ( https://media.fisheries.noaa.gov/2020-12/User_Manual%20_DEC_2020_508.pdf?null ), and NMFS calculator tool for estimating isopleths to Level B harassment thresholds also incorporates the use of spherical spreading. NMFS has determined that spherical spreading is the most appropriate form of propagation loss for these surveys and represents the best scientific information available.

Comment 7: Commenter(s) stated that auditory injury can occur below the PTS threshold and could occur below the TTS threshold. Further, that noise levels that did not manifest in PTS soon after an exposure event could cause irreversible neural damage in mammals after repeated or cumulative exposure. They also stated that the threshold for tissue injury has been found to occur at lower threshold than the threshold for TTS onset (Houser, 2021). NMFS' nearly singular focus on PTS distance (distance from activity at which partial or full permanent deafness will be induced in the whale) as the only indicator of “take” (premature death or reproductive failure affecting the population) is not reasonable. NMFS has no empirically derived direct measure of thresholds for PTS harm, but rather PTS is modeled from (limited) TTS data. NMFS is inappropriately defining “harm” to low-Frequency baleen whales as NMFS does not have any empirically-determined benchmark for what is the injury-causing sound pressure level (SPL) against which to measure the proposed activities.

Response: NMFS's TTS thresholds represent an onset of noise-induced hearing loss ( i.e., 6 dB threshold shift) and are considered the minimum threshold shift clearly larger than any day-to-day or session-to-session variation in a subject's normal hearing ability (Schlundt et al., 2000; Finneran et al., 2000; Finneran et al., 2002). There have been no indications that in marine mammals TTS occurs below our current thresholds. Furthermore, as Houser 2021 indicates “There are relatively few studies demonstrating that TTS can be associated with the destruction of tissue. To date, relevant studies have only been performed in terrestrial laboratory animals.” Studies on terrestrial mammals indicating neuropathy from noise exposure are associated with threshold shifts of 40 to 50 dB. Finally, PTS is defined as a threshold shift that does not fully recover back to baseline levels. It should not be assumed that an animal with PTS is deaf.

As stated in the proposed rule and reiterated here, there are no PTS data available for cetaceans and only one instance of PTS being induced in older harbor seals (Reichmuth et al., 2019). However, available TTS data (of mid-frequency hearing specialists exposed to mid- or high-frequency sounds (Southall et al., 2007; NMFS, 2018; Southall et al., 2019)) suggest that most threshold shifts occur in the frequency range of the source up to one octave higher than the source. We would anticipate a similar frequency range affected for PTS. Further, no more than a small degree of PTS is expected to be associated with any of the incurred Level A harassment, given it is unlikely that animals would stay in the close vicinity of a source for a duration long enough to produce more than a small degree of PTS. More information on PTS and TTS-PTS shift can be found in the “Negligible Impact Analysis and Determination” and the “Potential Effects of Underwater Sound on Marine Mammals” sections in the proposed rule. Furthermore, NMFS also relies on our behavioral harassment thresholds to assess potential effects occurring below levels associated with PTS and TTS. For information on the 160 dB threshold (onset of Level B behavioral harassment), please see our response to Comment 3. For more information related to PTS, please see our response to Comment 5.

Mitigation

Comment 8: Commenter(s) requested NMFS add to or modify the vessel strike avoidance mitigation measures contained within the proposed rule. Recommendations included “strengthening vessel speed restrictions”, and if weather or other conditions limit the range of observation, shutdown zones (including for transiting vessels) will be initiated keeping 500 meters (m) away from North Atlantic right whale. A commenter also incorrectly claimed that vessel speed restrictions are not fully mandated or enforced for offshore wind vessels.

Response: NMFS acknowledges that vessel strikes pose a risk to all large whales, including North Atlantic right whales and the proposed rule and this final rule require multiple mitigation measures to effect the least practicable adverse impact from vessels on marine mammals. These measures are more restrictive than other industrial, commercial, military, and recreational vessels. All transiting vessels (regardless of speed or size) are required to have a dedicated visual observer watching for marine mammals. In the event a marine mammal is observed under certain circumstances, the vessel must slow to 10 kn or less or, if within separation zones (which are encoded in regulation (62 FR 6729, March 17, 1997) or follow marine mammal viewing guidelines), turn away from and slow engines to neutral. In any SMA, DMA, Slow Zone (the latter two of which are currently voluntary for other vessels), Avangrid must operate vessels at 10 kn or less. Further, between November 1 and April 30, all vessels, regardless of size, in the specified geographical region must operate at 10 kn or less (11.5 mph). NMFS has determined it is impracticable for all vessels to travel 10 kn or less at all times and is not necessary to achieve the least practicable adverse impact given the mitigation discussed above. As described above, in many cases, there are no alternatives to the 10 kn or less speed restriction. However, NMFS has determined that when whales are less likely to be in the area and visual and acoustic monitoring is conducted, Avangrid vessels could travel at over 10 kn. NMFS has determined that the monitoring required, including both direct marine mammal monitoring and situational awareness monitoring and reporting, are sufficient to allow Avangrid vessels to travel at speeds greater than 10 kn when vessel strike risk is lowest when not subjected to the previously described restrictions.

In this final rule, NMFS is requiring that all vessels associated with Avangrid's activities must be equipped with a properly installed, operational Automatic Identification System (AIS) device and Avangrid must report all Maritime Mobile Service Identify (MMSI) numbers to NMFS Office of Protected Resources, thus facilitating monitoring of vessel speeds. In addition, NMFS maintains an Enforcement Hotline for members of the public to report violations of vessel speed restrictions. NMFS is not requiring PSOs to be onboard every transiting vessel as it is impracticable due to potential limited space on the vessels. However, as described in the proposed rule and carried forward in this final rule, Avangrid must have dedicated visual observers onboard all vessels with no other concurrent duties. The dedicated visual observer may be a PSO or a trained crew member.

Avangrid provided information pertaining to the types and number of vessels necessary to construct the project. They are also required to submit a Marine Mammal Vessel Strike Avoidance Plan, which must include, but is not limited to, more detail on ports used and means by which they would abide by the extensive measures outlined here. While NMFS acknowledges that vessel strikes can result in injury or mortality, we have analyzed the potential for vessel strike resulting from Avangrid's activity and, in consideration of the required mitigation measures specific to vessel strike avoidance included in the final rule NMFS has determined that the potential for vessel strike is so low as to be discountable and thus, no vessel strikes are expected or authorized to occur. These measures also ensure the least practicable adverse impact on species or stocks and their habitat.

Comment 9: Commenter(s) asserted an independent review of mitigation measures should be required due to limitations associated with visual monitoring and PAM.

Response: The MMPA does not require an independent review of mitigation measures. In contrast, it does require notice and opportunity for public comment (16 U.S.C. 1371(a)(5)(A)(i)). The public comment period is a means by which the public ( i.e., independent reviewers) are able to provide NMFS with mitigation measure recommendations supported by scientific evidence that NMFS takes into consideration when finalizing the rulemaking.

Comment 10: Commenter(s) recommended clarification should be included in the LOA that explicitly states if a shutdown would be initiated as a result of weather or other conditions that limit the range of observation.

Response: The comment refers to a 500-m shutdown zone for North Atlantic right whales; therefore, NMFS assumes the recommendation is referring to HRG surveys, a low impact activity. As described in the proposed rule and this final rule, PSOs are required to monitor the shutdown zone during operations. During periods of low visibility, alternative monitoring technology ( i.e., infrared or thermal cameras) must be used to monitor these zones. This final rule clarifies that when the shutdown zones become obscured for brief periods (no more than 30 minutes) due to inclement weather, survey operations may continue ( i.e., no shutdown is required) so long as no marine mammals have been detected. Further, the shutdown requirement is waived for certain genera of small delphids. As noted above, take of marine mammals from HRG surveys is limited overall, take by Level B harassment only is expected to occur only within a small area in close proximity to the vessel, and no Level A harassment is expected to result from exposure to the surveys even in the absence of mitigation. There is a low likelihood that short periods of obscured visibility might potentially coincide with a marine mammal entering the shutdown zone, and a shutdown not occurring. While such an event may result in a higher level exposure than would occur if the shutdown happened, such an exposure would still not be expected to result in a Level A take and would be brief and not change the number of takes or our evaluation of their likely effects, which again, are expected to be comparatively minor. Additionally, the frequent delay and/or cessation of HRG surveys creates operational challenges and impracticalities for applicants. Altogether, the required measures affect the least practicable adverse impact on the affected species.

Comment 11: Commenter(s) recommended that NMFS require mitigation measures that meet the least practicable adverse impact standard ( e.g., impacts of underwater noise be minimized to the fullest extent feasible) coupled with a robust monitoring and reporting program to ensure compliance.

Response: As described in both the proposed rule and this final rule, NMFS has included requirements for mitigation measures that effect the least practicable adverse impact on marine mammal species or stocks and their habitat, as required under the MMPA (16 U.S.C. 1371(a)(5)(A)(i)(II). As they relate to underwater noise, the mitigation measures include sound attenuation methods that successfully (evidenced by required sound field verification measurements) reduce real-world noise levels produced by impact pile driving, vibratory pile driving, and drilling of foundation installation to, at a minimum, the levels modeled assuming 10 dB of attenuation. NMFS clarifies that, because no unattenuated piles may be driven, there is no way to confirm a 10-dB reduction; rather, in situ SFV measurements will be conducted to ensure that sound levels are at or below those modeled assuming a 10-dB reduction. In addition to the SFV requirements in the proposed rule, consistent with the Biological Opinion (BiOp), we added to this final rule the requirement that Avangrid must conduct “Abbreviated SFV” monitoring (consisting of a single acoustic recorder placed at an appropriate distance from the pile) on all foundation installations for which the complete SFV monitoring ( i.e., “Thorough SFV”), as required in the proposed rule, is not carried out. NMFS is requiring that these SFV results must be included in the weekly reports. Any indications that distances to the Level A harassment and Level B harassment thresholds for whales are exceeded must be addressed by Avangrid, including an explanation of factors that contributed to the exceedance and corrective actions that were taken to avoid exceedance on subsequent piles.

NMFS has required numerous monitoring and reporting requirements which result in a robust compliance program.

Effects Assessment

Comment 12: Several commenters disagreed with NMFS' negligible impact determination, particularly for North Atlantic right whale. These comments included assertions that NMFS did not consider the imperiled population status of North Atlantic right whale; NMFS did not evaluate the cumulative effects of all projects (such as offshore wind construction and operational noise, underwater noise, and site characterization surveys and baseline background levels of ambient noise which result in stress); NMFS did not meaningfully examine the effects of the loss of communication space on marine mammals and, further, seems to misapprehend the spatial and temporal scope of the effects ( e.g., masking, disruption to courtship and mating behaviors, foraging/feeding, and TTS, etc.); that NMFS did not adequately assess the impact of behavioral disruption on feeding and similar behaviors resulting in decreased body condition nor the asserted increased risk of mortality from TTS; that any effect to the small number of breeding females can adversely affect fecundity and imperil the species; that NMFS has not used the best available science when reaching its NID by using the 160-dB threshold; and that NMFS did not consider whether abandonment of habitat that was designated with the express purpose of preventing vessel strikes would push the species further into a vessel traffic corridor, thereby elevating the risk to the species nor evaluated all the risks to North Atlantic right whale by habitat displacements as sublethal take has can a measurable effect due to the small population.

Response: NMFS is required to authorize the requested incidental take if it finds the total incidental take of small numbers of marine mammals by U.S. citizens “while engaging in that (specified) activity” within a specified geographical region during the 5-year period (or less) will have a negligible impact on such species or stock and, where applicable, will not have an unmitigable adverse impact on the availability of such species or stock for subsistence uses (16 U.S.C. 1371(a)(5)(A)). Negligible impact is defined as “an impact resulting from the specified activity that cannot be reasonably expected to, and is not reasonably likely to, adversely affect the species or stock through effect on annual rates of recruitment or survival” (50 CFR 216.103). Consistent with the preamble of NMFS' implementing regulations (54 FR 40338, September 29, 1989), the impacts from other past and ongoing anthropogenic activities are factored into the baseline, which is used in the negligible impact analysis. Here, NMFS has factored into its negligible impact analysis the impacts of other past and ongoing anthropogenic activities via their impacts on the baseline ( e.g., as reflected in the density/distribution and status of the species, population size and growth rate, and other relevant stressors).

The preamble of NMFS' implementing regulations also addresses cumulative effects from future, unrelated activities. Such effects are not considered in making the negligible impact determination under MMPA section 101(a)(5). NMFS considers: (1) cumulative effects that are reasonably foreseeable when preparing a National Environmental Policy Act (NEPA) analysis; and (2) reasonably foreseeable cumulative effects under section 7 of the ESA for ESA-listed species, as appropriate. Accordingly, NMFS has adopted and reviewed BOEM's EIS and as part of its inter-agency coordination. This EIS addresses cumulative impacts related to the Project and substantially similar activities in similar locations. Cumulative impacts regarding the promulgation of the regulations and issuance of a LOA for construction activities planned by Avangrid, have been adequately addressed in the adopted EIS that supports NMFS' determination that this action has been appropriately analyzed under NEPA. Separately, the cumulative effects of the Project on ESA-listed species, including the North Atlantic right whale, were analyzed under section 7 of the ESA when NMFS engaged in formal inter-agency consultation with the NOAA Greater Atlantic Regional Field Office (GARFO). The BiOp for the Project determined that NMFS' promulgation of the rulemaking and issuance of an LOA for construction activities, individually and cumulatively, are likely to adversely affect, but not jeopardize, listed marine mammals.

NMFS disagrees that our negligible impact determination is flawed or not supported. NMFS fully disclosed the imperiled status of North Atlantic right whales in the Description of Marine Mammals in the Area of Specified Activity section of the proposed rule. The proposed rule, as well as this final rule by reference, fully explains the impacts to North Atlantic right whales is expected to be limited to low-level behavioral harassment ( e.g., temporary avoidance or cessation of foraging). The proposed rule also described the Potential effects of behavioral disturbance on marine mammal fitness and that, based on the best available science, behavioral disturbance resulting from the specified activities is not expected to impact individual animals' health or have effects on individual animals' survival or reproduction, thus no detrimental impacts at the population level are anticipated. The commenters do not provide scientific evidence that suggests otherwise. Specifically, the commenters did not provide evidence that any effect to a breeding female would result in reduced fecundity.

Commenters suggested NMFS did not meaningfully evaluate loss of communication space; however, the Effects on Marine Mammals and Their Habitat in the proposed rule contained an analysis on the impacts of masking both in general and from the specified activities. NMFS also disagrees that TTS would result in increased risk of mortality. TTS was fully described in the Potential Effects of Underwater Sound on Marine Mammals and Potential Effects of Disturbance on Marine Mammal Fitness in the proposed rule. NMFS does not anticipate nor authorize serious injury or mortality of any marine mammal species for the specified activities.

NMFS acknowledges that whales may temporarily avoid the area where the specified activities occur. However, NMFS does not anticipate, based on the best available science, that whales will abandon their habitat, as suggested by a commenter, or be displaced in a manner that would result in a higher risk of vessel strike, and the commenter does not provide evidence that either of these effects should be a reasonably anticipated outcome of the specified activity. The primary activity that is anticipated to result in temporary avoidance of the otherwise used habitat is foundation installation pile driving and drilling. Not only would this activity be limited to times of year when North Atlantic right whale presence is low, pile driving and drilling would be intermittent, and only occur for a limited time over the course of 2 or 3 years (depending on schedule type). Together, these factors further reduce the likelihood that this species would be in close enough proximity to the activity to engage in avoidance behavior to the degree it would move into an area of risk (which would be closer to shore) that it could be struck by another vessel.

For NMFS' response on the use of the 160-dB threshold, please see our response to Comment 3.

Comment 13: Commenter(s) questioned the validity of NMFS small numbers analysis on the basis that the numbers do not account for the cumulative take numbers from previous, ongoing, or potential projects.

Response: NMFS has provided a reasoned approach to small numbers, as described in the “Taking Marine Mammals Incidental to Geophysical Surveys Related to Oil and Gas Activities in the Gulf of Mexico” final rule (86 FR 5322 at 5438, April 19, 2021). Utilizing that approach, NMFS has made the necessary small numbers finding for all affected species and stocks in this case (see Small Numbers section for more detail). Neither the MMPA nor our implementing regulations require the small numbers analysis to consider take from previous, ongoing, or potential projects.

Comment 14: Commenters suggested NMFS failed to account for the cumulative (or additive) impacts on marine mammal species in the analysis and that NMFS should evaluate the cumulative impacts of ongoing and future OSW projects rather than evaluating projects individually, including that NMFS must consider the total number of takes proposed to be authorized across all wind projects. They suggested that NMFS must fully consider the discrete effects of each activity and the cumulative effects of the suite of approved, proposed, and potential activities on marine mammals, including North Atlantic right whales, and ensure that the cumulative effects are not excessive before issuing a LOA.

Response: Neither the MMPA nor NMFS' implementing regulations call for consideration of the take resulting from other specified activities in the negligible impact analysis. The preamble to NMFS' implementing regulations (54 FR 40338, September 29, 1989) states, in response to comments, that the impacts from other past and ongoing anthropogenic activities are to be incorporated into the negligible impact analysis via their impacts on the baseline. Consistent with that direction, NMFS has factored into its negligible impact analysis the impacts of other past and ongoing anthropogenic activities via their impacts on the baseline ( e.g., as reflected in the density/distribution and status of the species, population size and growth rate, and other relevant stressors). The 1989 final rule for the MMPA implementing regulations also addressed public comments regarding cumulative effects from future, unrelated activities. There, NMFS stated that such effects are not considered in making findings under section 101(a)(5) concerning negligible impact. In this case, this ITR, as well as other ITRs currently in effect or proposed within the specified geographical region are appropriately considered an unrelated activity relative to the others. The ITRs are unrelated in the sense that they are discrete actions under section 101(a)(5)(A) issued to discrete applicants. Section 101(a)(5)(A) of the MMPA requires NMFS to make a determination that the take incidental to a “specified activity” will have a negligible impact on the affected species or stocks of marine mammals.

NMFS' implementing regulations require applicants to include in their request a detailed description of the specified activity or class of activities that can be expected to result in incidental taking of marine mammals, 50 CFR 216.104(a)(1). Thus, the “specified activity” for which incidental take coverage is being sought under section 101(a)(5)(A) is generally defined and described by the applicant. Here, Avangrid was the applicant for the ITR, and we are responding to the specified activity as described in that application and making the necessary findings on that basis.

Through the response to public comments in the 1989 implementing regulations (54 FR 40338, September 29, 1989), NMFS also indicated (1) that we would consider cumulative effects that are reasonably foreseeable when preparing a NEPA analysis and (2) that reasonably foreseeable cumulative effects would also be considered under section 7 of the ESA for listed species, as appropriate. Accordingly, NMFS has adopted an EIS written by BOEM and reviewed by NMFS as part of inter-agency coordination. This EIS addresses cumulative impacts related to the Project and substantially similar activities in similar locations. Cumulative impacts regarding the promulgation of the regulations and issuance of a LOA for construction activities, such as those planned by Avangrid, have been adequately addressed under NEPA in the adopted EIS that supports NMFS' determination that this action has been appropriately analyzed under NEPA. Separately, the cumulative effects of the Project on ESA-listed species, including North Atlantic right whales, was analyzed under section 7 of the ESA when NMFS engaged in formal inter-agency consultation with GARFO. The BiOp for the Project determined that NMFS' promulgation of the rulemaking and issuance of a LOA for construction activities associated with leasing, individually and cumulatively, are likely to adversely affect, but not jeopardize, listed marine mammals.

Comment 15: Commenter(s) claimed the request for an ITA should be denied alleging the specified activities kill marine mammals and some commenters suggested that the ongoing whale UMEs, including the whale deaths occurring in the winter of 2022-2023, are linked with ongoing offshore wind survey work ( i.e., HRG surveys). One commenter claimed the burden of proof is on NMFS to prove, with evidence, that there is no association between HRG surveys and whale injuries, including “rectified diffusion”, deaths or otherwise assume that offshore wind activity has contributed to these deaths. A commenter also asserted that the activities covered by the ITR and associated LOA are reasonably likely to result in Level A take of North Atlantic right whales that are not covered by the authorization's terms.

Response: Neither the proposed rule or this final rule allow mortality or serious injury of marine mammals to be authorized. The best available science indicates that the anticipated impacts from the specified activities potentially include avoidance, cessation of foraging or communication, TTS and PTS, stress, masking, etc. (as described in the Effects of the Specified Activities on Marine Mammals and their Habitat section in the proposed rule). NMFS emphasizes that there is no evidence that noise resulting from offshore wind development-related specified activities would cause marine mammal strandings, and there is no evidence linking recent large whale mortalities and currently ongoing offshore wind activities. The commenters offer no such evidence or other scientific information to substantiate their claim. This point has been well supported by other agencies, including BOEM and the Marine Mammal Commission (Marine Mammal Commission Newsletter, Spring 2023).

There is an ongoing UME for humpback whales along the Atlantic coast from Maine to Florida, which includes animals stranded since 2016, and we provide further information on the humpback UME in the humpback whale subsection in the Description of Marine Mammals in the Specified Geographical Region section of this final rule. Partial or full necropsy examinations were conducted on approximately half of the whales that recently stranded along the U.S. east coast. Necropsies were not conducted on other carcasses because they were too decomposed, not brought to land, or stranded on protected lands ( e.g., national and state parks) with limited or no access. Of the whales examined (roughly 90), about 40 percent had evidence of human interaction, either ship strike or entanglement. Vessel strikes and entanglement in fishing gear are the greatest human threats to large whales. The remaining 50 necropsied whales either had an undetermined cause of death (due to a limited examination or decomposition of the carcass) or had other causes of death including parasite-caused organ damage and starvation. The best available science indicates that only Level B harassment, or disruption of behavioral patterns ( e.g., avoidance), may occur as a result of the Project's HRG surveys. NMFS emphasizes that there is no credible scientific evidence available suggesting that mortality and/or serious injury is a potential outcome of the planned survey activity.

The proposed rule and this final rule state that no take of North Atlantic right whales by Level A harassment, mortality, or serious injury was requested or proposed for authorization (see the Estimated Take and Negligible Impact Analysis and Determination sections), and they are not expected based on the best available science.

One commenter cited literature as evidence that seismic surveys in the mid to low frequency range can injure whales, can cause decompression sickness (the bends) and can cause rectified diffusion. The Fernandez (2005) paper cited refers to pathology results from necropsies conducted on beaked whales involved in a mass stranding event in the Canary Islands following high intensity military training exercises involving numerous surface warships and several submarines and mid-frequency tactical sonar activities. NMFS acknowledges the effects of these activities described by the commenter are known; however, the activities in that paper are not analogous to HRG surveys that would be conducted by Avangrid to construct the Project, and the information presented by the commenter is not applicable due to many factors ( e.g., pile driving is stationary, versus the sound sources cited, and HRG surveys utilize a much lower source level).

Comment 16: Commenter(s) recommended NMFS consider the impacts of structure presence and operations, including those from operational turbine noise on marine mammals as well as ocean mixing and vibrations on phytoplankton, zooplankton, and the food chain. Commenter(s) suggested that NMFS did not evaluate the long-term operational and maintenance impacts of the project on marine mammals and ignored the best available science demonstrating behavioral impacts to marine mammals from operational turbines; therefore, NMFS' small numbers and negligible impact findings are arbitrary and capricious.

Response: In the proposed rule, NMFS considered the impacts to marine mammals from operational noise and to their habitat, including prey, from the presence of structures and operations based on the best available science. In this final rule, NMFS has supplemented that analysis with new scientific information that has become available regarding these issues since publishing the proposed rule. This new information does not change our findings. The commenter did not provide scientific evidence that suggests the analysis within the proposed rule was unsupported. NMFS has fully evaluated the potential impacts of both issuing this final rule on marine mammals over the five year effective period of this rulemaking and the potential impacts from long-term operations via the BiOp. We refer the reader to the Effects of the Specified Activities on Marine Mammals and Their Habitat section and the Negligible Impact Determination section in the proposed and this final rule for further details.

Other

Comment 17: Commenter(s) requested that NMFS consideration of LOAs for offshore wind developers be applied equitably across industries ( e.g., fishing industry) and that there be a clear threshold for OSW-related takes regionally and across project phases. In addition, the OSW-industry must be held accountable for incidental takes from construction and operations separately from the take authorizations for managed commercial fish stocks. Commenters) also asserted the OSW industry must be held accountable for their impacts on marine mammals as other industries are ( e.g., seasonal closures on fisheries, marine mammal entanglements).

Response: NMFS considers all ITA requests equally, all takes and regulatory measures are project-specific. NMFS carefully reviews models and take estimate methodology to authorize a number of takes, by species and manner of take that is a likely outcome of the Project. There are several conservative assumptions built into the models to ensure the number of takes authorized is sufficient based on the description of the Project. Therefore, takes authorized, being specific to a project, are managed separately than takes associated with any other project or industry. Avangrid would be accountable to the measures described in their ITA that were set to achieve “the least practicable impact on such species or stock and its habitat”. These include mitigation, monitoring, and reporting measures ( e.g., seasonal closures, gear-specific mitigation measures to avoid entanglements, etc.).

Avangrid would be required to submit frequent reports which would identify the number of takes applied to the Project. In the unexpected event that Avangrid exceeds the number of takes authorized for a given species, the MMPA and its implementing regulations state that NMFS shall withdraw or suspend the 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, or the taking allowed is having, or may have, more than a negligible impact on the species or stock concerned (16 U.S.C. 1371(a)(5)(B); 50 CFR 216.206(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 216.206(g)).

Moreover, as noted previously, fishing impacts, and NMFS assessment of them, generally center on entanglement in fishing gear, which is a very acute, visible, and severe impact ( i.e., mortality or serious injury). In contrast, the impacts incidental to the specified activities are primarily acoustic in nature and limited to Level A harassment and Level B harassment, there is no anticipated or authorized serious injury or mortality that the fishing industry could theoretically be held accountable for. Any take resulting from the specified activities would not be associated with take authorizations related to commercial fisheries. Neither the MMPA nor our implementing regulations require NMFS to analyze impacts to other industries ( e.g., fisheries) from issuance of an ITA pursuant to section 101(a)(5)(A). We note that the New England Wind Final EIS assesses the impacts of both BOEM and NMFS' actions (approving Avangrid's activities and authorizing the associated take of marine mammals, respectively) on the human environment, including to fisheries, and NMFS considered the analysis, as appropriate, in the final decisions under the MMPA. The impacts of commercial fisheries on marine mammals and incidental take for said fishing activities are managed separately from those of non-commercial fishing activities such as offshore wind site characterization surveys, under MMPA section 118.

Comment 18: Commenter(s) questioned what will happen if incidental take is exceeded, and the implications of it.

Response: In the unlikely scenario that Avangrid exceeds their authorized take levels, any further take would be unauthorized and therefore, prohibited under the MMPA. Avangrid could request additional incidental take of marine mammals from their specified activities. This would require NMFS to reanalyze its small numbers and negligible impact determinations and may require reinitiation of the BiOp and supplemental NEPA analysis depending on the specific facts.

Comment 19: Commenter(s) expressed concern about NMFS' ability to conduct marine mammal assessment aerial surveys would be detrimentally impacted as a result of offshore wind structures, thus impacting NMFS' ability to continue using current methods to fulfill its mission of precisely and accurately assessing and managing protected species.

Response: NMFS and BOEM have collaborated to establish the “Federal Survey Mitigation Strategy for the Northeast U.S. Region” (Hare et al., 2022). This interagency effort is intended to guide the development and implementation of a program to mitigate impacts of wind energy development on fisheries surveys. For more information on this effort, please see https://repository.library.noaa.gov/view/noaa/47925.

Changes From the Proposed to Final Rule

Since the publication of the proposed rule in the Federal Register (88 FR 37606, June 8, 2023), NMFS has made changes, where appropriate, in response to public comments and new information provided by Avangrid that are reflected in the regulatory text and preamble text of this final rule. Specifically, as described above, Avangrid refined and updated their acoustic modeling for foundation installation activities since the proposed rule which resulted in changes to the exposure estimates and requested take. These changes are briefly identified below, with more information included in the indicated sections of this final rule:

Changes in Information Provided in the Preamble

The information found in the preamble of the proposed rule was based on the best available information at the time of publication. Since publication of the Proposed Rule, new information has become available, which has been incorporated into this final rule as discussed below.

The following change was made throughout the final rule:

At the request of Park City Wind and consent of Avangrid, references to Park City Wind were replaced with Avangrid and lease number OCS-A 0561 was added, where appropriate, since lease area OCS-A-0534 was segregated.

The following changes were made to the Purpose and Need for Regulatory Action section of the preamble to this final rule:

We have added regulatory definitions under Legal Authority for the Final Action for ease of reference.

The following changes were made to the Summary, Summary of Request and Description of the Specified Activity sections of the preamble to this final rule:

We have included OCS-A 0561 as Avangrid segregated the OCS-A 0534 lease area in to two parts: OCS-A 0534 encompasses phase 1 and 0561 encompasses phase 2.

The following changes are reflected in the Description of Marine Mammals in the Specified Geographical Region section of the preamble to this final rule:

NMFS clarified the boundaries of the specified geographical region such that the Mid-Atlantic Bight is defined as from Cape Hatteras, North Carolina to Cape Cod, Massachusetts and extending into the western Atlantic to the 100-m isobath.

Given the release of NMFS' draft 2023 stock assessment reports (SARs; 89 FR 5495, January 29, 2024), we have updated the population estimate used in the proposed rule (Hayes et al., 2023) for the North Atlantic right whale ( Eubalaena glacialis) from 338 to 340 and the total mortality/serious injury (M/SI) amount from 8.1 to 27.2. This increase is due to the inclusion of undetected M/SI (whereas 8.1 accounted only for detected M/SI). As stated in the 2023 draft SARs, the use of the refined methods of Pace et al. (2021), the estimated annual rate of total mortality of adults and juveniles for the period 2016-2020 was 27.2, which is over 3 times larger than the 8.1 total derived from reported mortality and serious injury for the same period.

We have also made updates to the UME summaries for North Atlantic right whales, humpback whales, minke whales, and phocid seals (pinnipeds).

The following changes are reflected in the Estimated Take, Mitigation, and Monitoring and Reporting sections the preamble to this final rule:

NMFS received a number of modeling and density updates from the applicant since the proposed rule, which resulted in associated changes in the size of harassment zones, take numbers, and mitigation zones. As a result of the updated and refined modeling, we have updated the methods by which distances to NMFS harassment thresholds were estimated, the distances to NMFS harassment thresholds, the exposure estimates based on the updated acoustic modeling, and requested and allowable take amounts (which, generally speaking, went down as a result of these modeling refinements). NMFS notes that there were no changes to the number of foundations, construction schedule, or the assumption of 10 dB of noise attenuation as described in the proposed rule. The modeling and density changes are briefly listed here and described in more detail below:

• Upgraded, more refined take estimation modeling of vibratory pile driving, to reflect that which was presented in the proposed rule for impact pile driving (with animats). The revised modeling for vibratory setting of piles (followed by impact pile driving) replaced the practical spreading loss approach with acoustic modeling; and exposures for impact pile driving and vibratory setting were updated using animal movement modeling. This resulted in a notable reduction in exposure ranges and takes by Level B harassment.
• Upgraded sound source propagation modeling of the impact pile driving source, which resulted in little change in take or mitigation zones. The acoustic modeling was upgraded for impact piling as the previous energy-based parabolic equation model used to compute the near-field equivalent source before long range propagation was revised after the proposed rule using JASCO's Full-Wave PE RAM model (FWRAM) to compute the near-field equivalent source before the long-range propagation was computed (also using FWRAM).
• Upgraded sound source propagation modeling of the drilling activity (in lieu of 15 logR spreading), which resulted in some minor reductions in take. The acoustic updated modeling completed for drilling replaced the previous practical spreading loss approach; exposures were calculated by multiplying the zone of influence (ensonified area) by density.
• Improvements to the apportionment of species takes within species guilds (pilot whales, seals). Updates were made by the applicant to guilded species densities for vibratory setting followed by impact pile driving, impact pile driving alone, and drilling.
• An update to the model assumptions for high frequency species (harbor porpoise). This change reduced the exposure ranges and, subsequently, amount of takes by harassment.

Following the proposed rule, new modeling was performed for vibratory pile driving which replaced the previous practical spreading loss approach that defined the distance to Level B harassment as 50 kilometer (km). For the final rule, acoustic modeling was completed for vibratory setting of piles followed by impact driving, and exposures were modeled using animal movement modeling (animat), mirroring the method described in the proposed rule for impact pile driving. In general, the animat modeling resulted in the exposure distance to Level B harassment per species decreasing (most species' distance to the Level B harassment threshold were around 25 km) and, as marine mammals densities were applied depending on the exposure range using the 95th percentile exposure range (ER₉₅% ), exposure estimates and takes decreased. Instead of using a broad 50-km distance for estimating exposure and marine mammal density, such as was done in the proposed rule, the exposure estimates and take applied the marine mammal densities at 10 km, 25 km, or 50 km, using the using the next highest density match to the exposure range. For example, if the ER₉₅% was 8.5 km, the 10 km perimeter would be used. These revisions to the more refined modeling methods of estimating take for vibratory pile driving resulted in notable reductions in the Level B take estimates. The primary model refinement that resulted in the majority of the reduction in exposures and take in this final rule was from this change in vibratory pile driving modeling.

Following the proposed rule, the modeling methodology for impact pile driving was refined. In the prior modeling for impact pile driving, an energy-based parabolic equation (PE) model (JASCO's MONM) was used to compute the near-field equivalent source before long range propagation. For the final rule, JASCO's Full-Wave PE RAM model (FWRAM) was used to compute the near-field equivalent source before the long-range propagation was computed (also using FWRAM). FWRAM is an improvement because it calculates full synthetic pressure waveforms (in the time domain), as opposed to summed energy independent of time. Like MONM, FWRAM is range dependent for range-varying marine acoustic environments and takes environmental inputs (bathymetry, water sound speed profile, and seabed geoacoustic profile) into account. FWRAM computes pressure waveforms via Fourier synthesis of the modeled acoustic transfer function in closely spaced frequency bands, and employs the array starter method to accurately model sound propagation from a spatially distributed source (MacGillivray and Chapman 2012). Ultimately, little difference was observed between the prior sound fields with near-field equivalents computed using MONM versus the current modeling with FWRAM, though FWRAM is expected to be a more accurate model.

As part of the above modeling updates to impact pile driving and vibratory pile driving followed by impact pile driving (MONM to FWRAM modeling), changes resulted in the exposure ranges for high-frequency cetaceans (harbor porpoise). PE based models such as MONM and FWRAM are particularly well suited for modeling the propagation of low frequency sounds, such as impact pile driving, but are limited in terms of the total and upper frequency range they can accurately and efficiently model (Etter, 2012). For this reason, propagation must be modeled to some upper cut-off frequency. Beyond this frequency, a linear extrapolation (or roll-off) can be assumed in order to extend the results to higher frequencies. The slope of this roll-off is based on measured pile driving data and chosen to be conservative. Selection of a proper upper cut-off frequency depends on available computational resources, as well as the specific implementation of the PE method of a particular model (Laws, 2013). Because of this, and inherent differences of the two modeling methodologies, the cut-off used in the original modeling for the proposed rule was 300 Hz, while the cut-off in the revised model is 1,000 Hz. Therefore, the new modeling represents a more accurate methodology for frequencies between 300 and 1,000 Hz, as full propagation modeling is performed in this frequency range, rather than an approximate extrapolation (or roll-off). Both modeling approaches produce the same results at low frequencies where pile driving sound is dominant, but since the conservatively chosen roll-off started at 300 Hz, there is more higher frequency energy in the original model than in the revised model. For this reason, the two approaches produce similar results for low-frequency cetaceans, but the revised modeling results in substantially different exposure ranges for high-frequency cetaceans. Following the proposed rule, new modeling was performed for drilling which replaced the previous practical spreading loss approach that defined the distance to Level B harassment as 16.6 km. For the final rule, acoustic modeling was completed for drilling and exposures were calculated by multiplying the zone of influence (ensonified area) by density. Rather than using practical spreading, sound propagation is modeled using a combination of an energy-based parabolic equation (PE) model (JASCO's MONM) at frequencies up to 1 kHz, and the BELLHOP ray tracing model (Porter and Liu 1994) from 1 to 25 kHz. BELLHOP is a widely used Gaussian beam ray-trace propagation model, which incorporates bathymetry, sound speed profiles, and a simplified representation of the sea bottom; as sub-bottom layers have a negligible influence on the propagation of acoustic waves with frequencies above 1 kHz. Sound attenuation due to seawater absorption was included, which can be important for frequencies greater than 5 kHz. The drill was approximated as a point source located at mid-water depth. Further details regarding MONM are provided below, in the context of pile driving. The density perimeter was determined using the longest 10-dB attenuated 95th percentile acoustic range to the behavioral threshold (R₉₅% ) for all locations, rounded up to the nearest 5 km, and then applied around the entire lease area ( i.e., 7.1 km rounded up to 10 km). This new approach is expected to more accurately capture the spatial extent of the sound fields, as it includes an updated source level (191.6 dB) as well as more sophisticated propagation modeling which accounts for bathymetry, sound speed profiles, interaction with the seabed, and seawater absorption. This refinement in the drilling model also resulted in some minor reductions in exposure and take. Further details can be found in the Modeling and Take Estimates section.

In order to better reflect available species data specific to the area, we have also updated the methodology for estimating take for species combined into one guild in the Roberts et al. density models (harbor seals, grays seals, long-finned pilot whales, and short-finned pilot whales), by using local abundance data to define how the takes within a guild should be apportioned by species or stock as opposed to using SAR abundance data to define how takes should be apportioned with a guild, and subsequently, updated take by Level B harassment authorized for these species.

As a result of the updated modeling, NMFS has changed (some increases, some decreases) the minimum visibility zone, clearance zones, and shutdown zones for all species during foundation installation activities. The clearance and shutdown zones sizes for each foundation type ( i.e., monopile, jacket) are now based on the largest distance to Level A harassment threshold of all the foundation installation methods ( i.e., impact pile driving, vibratory pile driving, drilling), with a 20 percent increase to the clearance zone. Avangrid requested, and NMFS has carried forward, zone sizes by the largest foundation type ( i.e., monopile, jacket) and hammer size. Lastly, Avangrid did not request different zone sizes based on the 12-m monopile versus the 13-m monopile in their January 2024 Application Update as they did prior to the proposed rule. Instead, Avangrid proposed zone sizes based on the 13-m monopile at 6,000 kJ, though this foundation installation scenario remains unlikely though possible. NMFS has therefore set the zone sizes as the largest across all foundation and hammer sizes for each foundation type (monopile, jacket), regardless if Avangrid choses to install a smaller pile or use a smaller hammer during real-world foundation installation. However, Avangrid may request modifications through adaptive management should sound field verification (SFV) demonstrate noise levels are lower than expected.

As a result of the new modeling, the monopile visual (PSO) and acoustic (PAM) clearance zone sizes for other baleen whales and sperm whale has decreased from 4,700 m for all pile driving and drilling to 3,300 m (all installation methods); the pile driving and drilling shutdown zones has similarly decreased from 4,700 m (12-m) and 5,500 m (13-m) to 2,700 m (all installation methods). The refined modeling for harbor porpoise decreased the zone sizes from 2,300 m (monopile pile driving and drilling) to 250 m, as the maximum injury (ER₉₅% ) for harbor porpoise is 240 m. The zone sizes for seals decreased from 1,100 m (monopile impact pile driving) and 1,400 m (monopile vibratory pile driving or drilling) to 200 m (all monopiles and installation methods) as the maximum injury (ER₉₅% ) for seals was 0 m. The clearance and shutdown zones for small whales and dolphins remain unchanged (200 m) as the maximum injury (ER₉₅% ) is 0 m. For those species that modeling resulted in less than 200 m Level A harassment distance to threshold, NMFS has set the minimum clearance and shutdown zone size as 200 m to ensure the zones are outside the monopile's noise attenuation system (NAS). This was also the approach in the proposed rule.

Based on the model changes above, the updated jacket (all pin piles) visual (PSO) and acoustic (PAM) clearance zone sizes for other baleen whales and sperm whale has increased from 4,500 m for impact pile driving and 4,700 m for vibratory pile driving and drilling to 4,900 m (all installation methods); the pile driving and drilling shutdown zones has decreased from 4,500 m for impact pile driving and 4,700 m for vibratory pile driving and drilling to 4,100 m (all installation methods). The refined modeling for harbor porpoise decreased the zone sizes from 1,800 m (impact pile driving) and 2,300 m (vibratory pile driving and drilling) to 250 m as the maximum injury (ER₉₅% ) for harbor porpoise is 230 m. The zone sizes for seals decreased from 1,400 m (all pile driving and drilling) to 1,000 m (clearance) and 800 m (shutdown) for all installation methods as the maximum injury (ER₉₅% ) for seals was 790 m. The clearance and shutdown zones for small whales and dolphins remain unchanged (50 m) as the maximum injury (ER₉₅% ) was 0 m. For those species that modeling resulted in less than 50 m Level A harassment distance to threshold, NMFS has set the minimum clearance and shutdown zone size as 50 m to ensure the zones are outside the jacket's noise attenuation system (NAS). This was also the approach in the proposed rule.

NMFS has not changed the North Atlantic right whale shutdown and clearance zones for visual observations ( i.e., any distance), NMFS has set the acoustic clearance and shutdown zones during foundation activities for North Atlantic right whale to any acoustic detection within a 12-km acoustic monitoring zone which were previously set to 5,600 m (monopile impact pile driving), 4,500 m (monopile vibratory pile driving and drilling), and 4,500 m (jacket pile driving and drilling). This final rule also clarifies that PAM must be conducted before, during, and after foundation installation and UXO/MEC detonation for North Atlantic right whales but the PAM system should be designed to detect all other marine mammals to the maximum extent practicable.

We updated the minimum visibility zone based on the new modeling from Avangrid (largest ER₉₅% distance to Level A harassment for low-frequency cetacean, not including fin whale), for all species during each foundation installation type then rounded for PSO clarity. As a result of the new modeling, the final rule sets the minimum visibility zone for monopiles at 2,100 m (humpback whale, 2,070 m), 3,400 m for jacket installation (humpback whale, 3,320 m), and 500 m for HRG (unchanged from the proposed rule). As described in the preamble of the proposed rule (page 405), NMFS originally set the minimum visibility zone size based on the North Atlantic right whale ER₉₅% distance to the Level A harassment threshold, assuming 10 dB. NMFS recognizes that a footnote in table 35 of the proposed rule used incorrect terminology stating that the minimum visibility zone for North Atlantic right whale would be “any distance” which contradicted the earlier stated methodology for setting the minimum visibility zone and would not be practicable. As a result of the updated modeling, the minimum visibility zone in this final rule decreased, however, it is still larger than the updated North Atlantic right whale ER₉₅% distance to the Level A harassment threshold, assuming 10 dB. To align with the BiOp, NMFS has used the largest ER₉₅% distance to Level A harassment for low-frequency cetacean, not including fin whale, which uses the distance to Level A harassment for humpback whale which is greater than the ER₉₅% distance to Level A harassment for North Atlantic right whale (monopile 2,070 m vs 1,620 m; jacket 3,320 m vs 2,350 m).

We have reduced takes by Level B harassment for Northern bottlenose whale from 12 to 8 as a result of a typo correction submitted by the applicant in the January 2024 Application Update. The applicant had previously not adjusted the total take request for this rare species by assuming encounters every other year but instead had unintentionally summed all annual takes at the time of the proposed rule. The takes by Level B harassment for Northern bottlenose whale in this final rule have been corrected based on encounters every other year.

NMFS has re-organized and simplified the monitoring and reporting section to avoid repeating entirely the requirements provided in the regulatory text. NMFS has renamed the North Atlantic Right Whale Vessel Strike Avoidance Plan to the Marine Mammal Vessel Strike Avoidance Plan to more accurately reflect that the plan does not solely apply to North Atlantic right whales.

In response to commenters' concerns regarding noise attenuation, we have added a general requirement that Avangrid must lower noise levels should they exceed those modeled assuming 10 dB of attenuation. Based on multiple commenters' concerns regarding noise attenuation, and as informed by preliminary sound measurements from South Fork Wind, NMFS has added a requirement that two functional noise attenuation devices that reduce noise levels to the modeled harassment isopleths, assuming a 10-dB attenuation, must be used during foundation pile driving. A single bubble curtain alone will not be allowed for use in mitigation.

In response to commenters' concerns on vessel activity relating to the Project, all project vessels must utilize AIS device and must report all MMSI numbers to NMFS Office of Protected Resources;

This final rule clarifies that the mitigation measure restricting Project vessels from traveling over 10 kn (5.14 m/s) in the transit corridor, unless Avangrid conducts real-time acoustic monitoring to detect large whales (including North Atlantic right whales), applies only when other speed restrictions are not in place.

For foundation installation, NMFS notes that it is difficult to specify a reduction in energy for any given hammer because of variation across drivers and installation conditions. Because other industry operators have identified that specific soft-start procedures, such as those included in the proposed rule, may raise concerns regarding engineering feasibility and practicability, we have removed the specifics related to the soft-start procedure identified in the proposed rule (but not the requirement to conduct a soft-start), allowing for flexibility should the need for adjustments to the specific procedures arise. However, any alternative protocol would be as protective as the generic coastal construction soft-start specifications provided in the proposed rule. The final soft-start methodology will be developed by Avangrid, in consultation with NMFS, considering final design details including site-specific soil properties and other considerations.

To align with the BiOp, NMFS has updated the UXO/MEC detonation zones to be specific to charge weight. The clearance zones, which are visually and acoustically monitored, were derived based on an approximate proportion of the size of the Level B harassment (TTS) isopleth then rounded for PSO clarity. The modeled distances to NMFS harassment thresholds have not changed from the UXO/MEC Acoustic Analysis Report in the application. The clearance zone sizes are contingent on Avangrid being able to demonstrate that they can identify charge weights in the field; if they cannot identify the charge weight sizes in the field then would need to assume the E12 charge weight size for all detonations and must implement the E12 clearance zone. No minimum visibility zone is required for UXO/MEC detonation as the entire visual clearance zone must be clear given the potential for lung and gastrointestinal tract injury.

We updated the process for obtaining NMFS approval for PSO and PAM Operators and have clarified education, training, and experience necessary to obtain NMFS' approval.

To align with the BiOp, we have added a requirement to have at least three active PSOs on the foundation installation platform ( e.g., pile driving/drilling vessel) and any dedicated PSO vessel (or equivalent coverage) rather than two PSOs, as was originally described in the proposed rule. Addition of this requirement is based on NMFS' evaluation of PSO coverage abilities for similar projects in the area ( e.g., Sunrise Wind) and has found that three PSOs (each covering 120 degrees) will improve the reliability of detection from the PSO platforms ( e.g., pile driving/drilling vessel, PSO-dedicated vessel, etc.). Previously at least four on-duty PSOs were required to actively observe for marine mammals before, during, and after installation of foundation piles ( i.e., monopiles and pin piles), at least two of those PSOs must be stationed and observing on the pile driving vessel and at least two PSOs must be stationed on a secondary, PSO-dedicated vessel. NMFS is now requiring Avangrid to deploy three on-duty PSOs per platform and vessel instead of two. Alternatively, Avangrid may propose an alternative method other than three PSOs per platform that provides equal or greater visual monitoring effectiveness. Similarly, NMFS is now requiring that Avangrid must deploy at least three on-duty PSOs, instead of two on-duty PSOs, on each observation platform for all detonations. To align with the BiOp, NMFS is also requiring the use of two PSO-dedicated vessels in addition to the PSOs on the foundation installation platform.

NMFS added a requirement that a double big bubble curtain must be placed at a distance that would avoid damage to the nozzle holes during all UXO/MEC detonations. NMFS also added a requirement that a pressure transducer must be used during all UXO/MEC detonations.

Consistent with the BiOp, NMFS added additional details regarding thorough SFV requirements and added a requirement for Abbreviated SFV (consisting of a single recorder with a bottom and mid-water column hydrophone). We have also added requirements that Thorough SFV must be conducted on every pile until measured noise levels are at or below the modeled noise levels, assuming 10 dB; the minimum number of foundations previously required to have SFV has increased and now includes requirements for each construction year; and we have added a requirement that Avangrid must deploy at least eight hydrophones at four locations (one bottom and one mid-water column at each location) along an azimuth that is likely to see lowest propagation loss and two hydrophones (one bottom and one mid-water) at 750 m, 90 degrees from the primary azimuth during installation of all piles where Thorough SFV monitoring is required. Lastly, we have clarified that during Thorough SFV, installation of the next foundation (of the same type/foundation method) may not proceed until Avangrid has reviewed the initial results from the Thorough SFV and determined that there were no exceedances of any distances to the identified thresholds based on modeling assuming 10 dB of attenuation.

We have removed the requirements for reviewing data on an annual and biennial basis for adaptive management and instead will make adaptive management decisions as frequently as new information warrants it.

Changes in the Regulatory Text

As described above regarding changes made to the preamble, we have made the following corresponding and additional changes to the regulatory text in response to new information provided by Avangrid and public comments.

For clarity and consistency, we revised three paragraphs in § 217.320, “Specified activity and specified geographical region,” of the regulatory text to fully describe the specified activity, specified geographical region, and requirements imposed on the LOA Holder (Avangrid) and to clarify that the regulations apply to Avangrid Renewables LLC, as well as its successors or assigns, and those persons it authorizes or funds to conduct activities on its behalf. NMFS has also included the addition of OCS-A 0561 as a result of the OCS-A 0534 lease segregation.

For clarity, we have specified that any measures in §§ 217.324 and 217.325 required during jacket foundation installation are also required for bottom-frame foundations that utilize pile foundations.

In §§ 217.320, 217.322, 217.323, 217.324, 217.325, 217.326, and 217.327, NMFS has made minor changes to formatting and wording to more clearly state the requirements.

In § 217.324(a), NMFS has clarified that any visual observation of marine mammals, as opposed to only ESA-listed marine mammals, must be communicated to PSOs and vessel captains.

NMFS has clarified language in § 217.324(a) on what public sources Avangrid and its personnel must check and how often to stay informed on North Atlantic right whales detections in the area.

NMFS has added additional clarification on the authority of PSOs and PAM operators in § 217.324(a) to ensure compliance and proper implementation of the regulations.

NMFS has specified that any visual or acoustic detection of a North Atlantic right whale within clearance zones must trigger a delay in commencement of pile driving, drilling, UXO/MEC detonation, and HRG surveys. NMFS has also updated the requirement § 217.324(c)(8)(i) by expanding the terminology of “piles installed” to foundation installation activities, correcting the November 1-December 30 date range to November 1-December 31, and increasing the monitoring zone from 10 to 12 km.

NMFS has added a requirement that all project vessels must utilize AIS and must report all MMSI numbers to NMFS Office of Protected Resources.

NMFS has included a requirement for Avangrid to consent to on-site observations and inspections by Federal personnel during project activities.

NMFS has added a prohibition to interfering with PSO or PAM operator responsibilities.

NMFS has added a requirement for any large whale sighting to be communicated to all project-associated vessels, and for a large whale sighting log sheet to be retained for the vessel captain's review each day.

In § 217.324(b), NMFS has clarified the minimum separation zone for vessels when encountering a North Atlantic right whale.

In § 217.324(d), NMFS has added a requirement that Avangrid must notify NMFS 48 hours before any planned UXO/MEC detonation event unless this 48-hour notification would create delays to the detonation that would result in imminent risk to human life or safety. NMFS has also added a requirement that Avangrid may detonate a maximum of 10 UXO/MECs, of varying sizes but no larger than 1,000 pounds (lbs; 454 kilograms (kg)) charge weight ( i.e., E12), over the effective period of this rulemaking and LOA(s). NMFS has added a requirement that a pressure transducer must be used to monitor pressure levels during all UXO/MEC detonations.

NMFS has clarified the requirement in § 217.324(b) to specify that this measure applies to vessels traveling in the specified geographical region. NMFS has also renamed the North Atlantic Right Whale Vessel Strike Avoidance Plan requirement to the Marine Mammal Vessel Strike Avoidance Plan to more accurately reflect that the plan does not solely apply to North Atlantic right whales.

In consideration of commenters' concerns regarding strengthening mitigation measures to avoid vessel strike, NMFS has removed the requirement in § 217.324(b)(14) from the proposed rule for any underway vessel to avoid speed over 10 kn (18.5 km/hour) or abrupt changes in course direction until an animal is on a path away from the separation distance. The current requirement in § 217.324(b) requires vessels to steer a course away from, reduce speed and shift engine to neutral if an animal is within the separation distance.

NMFS has clarified the requirement in § 217.324(b)(7) from the proposed rule that a North Atlantic right whale detection triggers a speed restriction for all transiting vessels within 10 km for a 24-hour period (previously 12-hour period). This was previously specific to Slow Zones ( i.e., Dynamic Management Areas (DMAs) or acoustically-triggered slow zone), and Seasonal Management Areas (SMAs). NMFS has also added a requirement that vessels must not travel over 10 kn from November 1 through April 30, annually, within the specified geographical region. This measures also now includes a sub-measure that states: if vessel(s) are traveling at speeds greater than 10 kn (11.5 mph) ( i.e., no speed restrictions are enacted) in the transit corridor (defined as from a port to the Lease Area or return), in addition to the required dedicated visual observer, LOA Holder must monitor the transit corridor in real-time with PAM prior to and during transits. If a North Atlantic right whale is detected via visual observation or PAM detection within or approaching the transit corridor, all vessels in the transit corridor must travel at 10 kn (11.5 mph) or less for 24 hours following the detection. Each subsequent detection must trigger a 24-hour reset. A slowdown in the transit corridor expires when there has been no further visual or acoustic detection in the transit corridor in the past 24 hours. The transit corridor must be defined in the Marine Mammal Vessel Strike Avoidance Plan.

NMFS has clarified PAM boundaries for detections of North Atlantic right whales that trigger a delay in the commencement of foundation installation and UXO/MEC detonation.

In response to comments and to align with the BiOp, NMFS has added a requirement that two functional noise attenuation devices that reduce noise levels to the modeled harassment isopleths assuming a 10-dB attenuation, must be used during foundation installation (impact and vibratory pile driving, drilling) and UXO/MEC detonation.

NMFS has clarified requirements for PAM systems, including a requirement for the PAM system to be able to detect a vocalization of North Atlantic right whales up to 12 km away in § 217.324(c). In §§ 217.324 and 217.325, NMFS has removed NMFS-approved PAM systems(s) terminology as NMFS approves PAM plans and not PAM systems.

To align with the BiOp, NMFS has increased the number of on-duty PSOs on the foundation installation platform and the number of PSO-dedicated vessels to improve the reliability of marine mammal detection from the platform in § 217.324(c). The minimum number of PSOs per platform during UXO/MEC detonation has been increased to three in § 217.324(d).

NMFS added requirements related to conducting and reporting on Thorough and Abbreviated SFV to align with the BiOp in § 217.324(c)-(d).

NMFS has clarified requirements for clearance zones, shutdown zones, deactivating acoustic sources when not in use, PSO activity and communication requirements, and vessel operator communication requirements, applying to HRG surveys operating sub-bottom profilers (SBPs) in § 217.324(e) to ensure compliance and proper implementation of the regulations.

NMFS has added a requirement for acoustic source ramp-ups to be scheduled in order to minimize the time spent with the source activated.

For fishery monitoring surveys in § 217.324(f), NMFS has clarified language on emptying survey gear, gear deployment timing, trawl tow times and speed, and visual monitoring efforts.

The following changes are reflected in § 217.325, “Requirements for monitoring and reporting,” and the associated Monitoring and Reporting section of the preamble to this final rule:

NMFS has added a requirement for confirmation of all required training to be documented on a training course log sheet and reported to NMFS before initiating project activities. A description of the training program must be provided to NMFS at least 60 days prior to the initial training before in-water activities begin. NMFS has added a requirement that the marine mammal monitoring team must monitor available sources of information on North Atlantic right whale presence in or near the Project no less than every 4 hours.

NMFS has clarified PAM operator qualifications as well as PSO and PAM training requirements in § 217.235 to ensure compliance and proper implementation of regulations. This additional clarification includes detailed requirements for prior experience, being independent observers, ability for PAM operators to review and classify acoustic detections in real-time, PSO marine mammal identification and behavior training to focus on species specific to the North Western Atlantic Ocean, and PSO and PAM training to have been completed within the past 5 years and have included a certificate of course completion. NMFS has specified that Avangrid must submit the names of PSOs and PAM operators previously approved by NMFS at least 30 days prior to commencement of the specified activities and 15 days prior to when new PSO/PAM operators are required after activities have commenced.

NMFS has specified the following additional details in § 217.325(b) to clarify PSO and PAM operator requirements in order to ensure compliance and proper implementation of regulations: PSOs must monitor for marine mammals prior to, during, and following impact pile driving, vibratory pile driving, drilling, UXO/MEC detonation and HRG surveys that use sub-bottom profilers and monitoring must be done while free from distractions; all on-duty PSOs and on-duty PAM operator(s) are to remain in real-time contact with the on-duty construction personnel responsible for implementing mitigations; and the PAM operator must inform the Lead PSO(s) on duty of animal detections approaching or within applicable ranges of interest to the activity occurring via the data collection software system.

NMFS added requirements related to conducting and reporting on SFV (Thorough and Abbreviated) to align with the BiOp in § 217.325(c), (d), and (f).

NMFS added a requirement to § 217.325(c) for a Nighttime Monitoring Plan if Avangrid intends to request nighttime foundation installation. No nighttime foundation installation can occur until NMFS reviews and approves the plan.

NMFS clarified requirements for the PAM Plan and Marine Mammal Monitoring Plan to align with the BiOp in § 217.325(d).

NMFS has clarified the reporting requirements, such as, the format of dates must be in the MM/DD/YYYY format, location information must be provided in Decimal Degrees and with the coordinate system information, and which email addresses a report must be submitted to.

In consideration of public comments with concerns for underestimating takes by Level A harassment and Level B harassment, NMFS has added a requirement that if at any time during the Project Avangrid becomes aware of any issue or issues which may (to any reasonable subject-matter expert, including the persons performing the measurements and analysis) call into question the validity of any measured Level A harassment or Level B harassment isopleths to a significant degree, Avangrid must inform NMFS Office of Protected Resources within one business day of becoming aware of this issue or before the next pile is driven, whichever comes first.

NMFS has added specific regional contact information for reporting North Atlantic right whale sightings and stranded, entangled, injured, or dead marine mammals.

NMFS had added a requirement to report observations of any large whale (other than North Atlantic right whales) to the WhaleAlert app.

Recognizing the extensive, frequent, and situational monitoring data and report requirements, NMFS clarified the language describing the annual or biennial review of data to inform adaptive management decisions to indicate that adaptive management decisions may be made at any time, as new information warrants it.

Description of Marine Mammals in the Geographic Area

As noted in the Changes from the Proposed to Final Rule section, updates have been made to the abundance estimate for North Atlantic right whales and to the UME summaries of multiple species. These changes are described in detail in the sections below and, otherwise, the marine mammal information has not changed since the proposed rule.

Thirty-eight marine mammal species under NMFS' jurisdiction have geographic ranges within the western North Atlantic OCS (Hayes et al., 2023). Sections 3 and 4 of Park City Wind's (now Avangrid's) ITA application summarize available information regarding status and trends, distribution and habitat preferences, and behavior and life history of the potentially affected species (Park City Wind, 2022). Additional information regarding population trends and threats may be found in NMFS's SARs ( https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments ) and more general information about these species ( e.g., physical and behavioral descriptions) may be found on NMFS's website ( https://www.fisheries.noaa.gov/find-species ).

Table 2 lists all species and stocks for which take is expected and may be authorized for this action, and summarizes information related to the population or stock, including regulatory status under the MMPA and ESA, and provides the potential biological removal (PBR), where known. PBR is defined by the MMPA as the maximum number of animals, not including natural mortalities, that may be removed from a marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population (16 U.S.C. 1362(20)). While no mortality is anticipated or may be authorized, PBR and annual serious injury and mortality from anthropogenic sources are included here as gross indicators of the status of the species and other threats.

Marine mammal abundance estimates presented in this document represent the total number of individuals that make up a given stock or the total number estimated within a particular study or survey area. NMFS's stock abundance estimates for most species represent the total estimate of individuals within the geographic area, if known, that comprises that stock. For some species, this geographic area may extend beyond U.S. waters. All managed stocks in this region are assessed in NMFS's U.S. Atlantic and Gulf of Mexico SARs. All values presented in table 2 are the most recent available at the time of publication and are available in NMFS' 2023 draft SARs available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports.

In addition to the species listed in table 2, the Florida manatees ( Trichechus manatus; a sub-species of the West Indian manatee) has been previously documented as an occasional visitor to the Northeast region during summer months (U.S. Fish and Wildlife Service (USFWS), 2019). However, manatees are managed by the USFWS and are not considered further in this document.

As described in the proposed rule, the applicant also requested take for beluga whales ( Delphinapterus leucas), however, there is no beluga whale stock designated under the MMPA along the U.S. Eastern Seaboard as it is a more northerly species; therefore, they are not considered further in this document. A detailed description of the species likely to be affected by the Project, including brief introductions to the species and relevant stocks, information regarding population trends and threats, and information regarding local occurrence, were provided in the application and the proposed rule (88 FR 37606, June 8, 2023). Other than adjustments to population statistics ( e.g., North Atlantic right whale population abundance) and UME updates, we are not aware of any changes in the status of the species and stocks listed in table 2; therefore, detailed descriptions are not provided here. Please refer to the proposed rule for these descriptions (88 FR 37606, June 8, 2023). Please also refer to NMFS' website ( https://www.fisheries.noaa.gov/find-species ) for generalized species accounts.

Since the publication of the proposed rule, the following updates have occurred to the below species in regards to general information or their active UMEs.

North Atlantic Right Whale

In January 2024, NMFS released its draft 2023 SARs which updated the population estimate ( N _best) of North Atlantic right whales to 340 individuals (a decrease from the population estimate in the proposed rule ( n =368) but an increase from the final 2022 SARs ( n =338); the annual M/SI value dropped from the final 2022 SAR of 31.2 to 27.2 in the draft 2023 SAR. Beginning in the 2022 SARs, the M/SI for North Atlantic right whale included the addition of estimated undetected mortality and serious injury, which had not been previously included in the SAR. The current population estimate is equal to the North Atlantic Right Whale Consortium's 2022 Annual Report Card, which identifies the population estimate as 340 individuals (Pettis et al., 2023).

As described in the proposed rule, elevated North Atlantic right whale mortalities have occurred since June 7, 2017, along the U.S. and Canadian coast, with the leading category for the cause of death for this UME determined to be “human interaction,” specifically from entanglements or vessel strikes. Since publication of the proposed rule, the number of animals considered part of the UME has increased. As of April 12, 2024, there have been 39 confirmed mortalities (dead, stranded, or floaters), 1 pending mortalities, and 34 seriously injured free-swimming whales for a total of 74 whales. The UME also considers animals with sublethal injury or illness (called “morbidity”; n =52) bringing the total number of whales in the UME from 74 to 126. More information about the North Atlantic right whale UME is available online at: https://www.fisheries.noaa.gov/national/marine-life-distress/active-and-closed-unusual-mortality-events.

Humpback Whale

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 221 known cases (as of May 3, 2024). There has been no update to this UME since the proposed rule. More information is available at: https://www.fisheries.noaa.gov/national/marine-life-distress/active-and-closed-unusual-mortality-events.

Since December 1, 2022, the number of humpback strandings along the mid-Atlantic coast, from North Carolina to New York, 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 2022-2023 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

Since January 2017, a UME has been declared based on elevated minke whale mortalities detected along the Atlantic coast from Maine through South Carolina. As of May 3, 2024, a total of 168 minke whales have stranded during this UME. Full or partial necropsy examinations were conducted on more than 60 percent of the whales. Preliminary findings have shown evidence of human interactions or infectious disease in several of the whales, but these findings are not consistent across all of the whales examined, so more research is needed. More information is available at: https://www.fisheries.noaa.gov/national/marine-life-distress/active-and-closed-unusual-mortality-events.

Phocid Seals

Since June 2022, elevated numbers of harbor seal and gray seal mortalities have occurred across the southern and central coast of Maine. This event was declared a UME in July 2022 but closed after the proposed rule. The UME Investigative Team reviewed necropsy, histopathology, and diagnostic findings. They determined the UME was attributed to spillover events of the highly pathogenic avian influenza H5N1 virus from infected wild birds to harbor and gray seals. An ongoing HPAI H5N1 global outbreak in domestic and wild birds and wild mammals began in 2021. Live seals showed signs of respiratory and neurological disease including nasal and ocular discharge, coughing, unresponsiveness, and seizures. Eighteen percent of the stranded seals (33 out of 180) were tested for avian influenza via polymerase-chain-reaction. A subset of seals were positive for HPAI H5N1 with preliminary findings confirmed by the United States Department of Agriculture's National Veterinary Services Laboratories. Of the 33 seals tested during the UME period 19 (58 percent) were positive for H5N1 (17 harbor seals; 2 gray seals) and 14 (42 percent) tested negative. Twelve H5N1 positive seals had histopathology conducted; 11 of those seals had lesions (primarily respiratory and/or neurologic) suspected or consistent with avian influenza infection. Sequencing of the H5N1 virus detected in seals suggests the seals were infected from spillover events from infected wild birds to these seals. While the UME was not occurring in the area of the Project, the populations affected by the UME were the same as those potentially affected by the Project. Information on this UME is available online at: https://www.fisheries.noaa.gov/national/marine-life-distress/active-and-closed-unusual-mortality-events.

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-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 3.

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 (Hemilä et al., 2006; Kastelein et al., 2009; Reichmuth and Holt, 2013).

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

Potential Effects of Specified Activities on Marine Mammals and Their Habitat

Exposure to underwater noise and explosive detonations from the Project's specified activities have the potential to result in Level A harassment or Level B harassment of marine mammals in the specified geographical region, but no serious injury or mortality. The proposed rule (88 FR 37606, June 8, 2023) included a discussion of the effects of anthropogenic noise on marine mammals and the potential effects of underwater noise and explosive detonations from the Project's specified activities on marine mammals and their habitat. While some new literature regarding marine mammal distribution and habitat use has been published since publication of the proposed rule ( e.g., Holdman et al., 2023; Meyer-Gutbrod et al., 2023; Van Parijs et al., 2023; Westwell et al., 2024), there is no new information that NMFS is aware of that changes the analysis in the proposed rule. We provide a summary of these papers below.

Holdamn et al. (2023) studied harbor porpoise habitats in the Gulf of Maine (GOM) and Southern New England waters providing baseline data on the occurrence and foraging activity of porpoises from 2020 to 2022. Harbor porpoises were present year-round in the GOM with peak detections in the summer and fall. The observed seasonal pattern of harbor porpoise occurrence in this study is consistent with prior information on the general distribution of the GOM/Bay of Fundy stock (Wingfield et al., 2017; NMFS, 2021). In line with previously reported distribution patterns, harbor porpoise occurrence in Southern New England was high in fall, winter and spring, but porpoises were largely absent in the summer. Results from generalized additive models suggest that time of year, hour of day, lunar illumination, and temperature are significant contributors to harbor porpoise presence (detection mainly through echolocation clicks) and/or foraging effort.

Meyer-Gutbrod et al. (2023) studied North Atlantic right whale sightings from 1990-2018 to examine patterns in monthly habitat use in 12 high-use areas to broadly characterize new seasonal habitat-use patterns across the core North Atlantic right whale range. As North Atlantic right whale foraging habitat selection is driven by complex spatial and temporal patterns ( e.g., prey abundance), abundances of Calanus finmarchicus (a species of copepod and a component of the zooplankton found in the northern Atlantic Ocean) and Calanus hyperboreus (species of copepod found in the Arctic Ocean and northern Atlantic Ocean) were also analyzed for decadal variations in the North Atlantic right whale foraging habitats. The research found that in comparison to the 2000s, the 1990s and the 2010s were similar in that North Atlantic right whale sightings ( i.e., Sightings Per Unit Effort (SPUE)) declined in the foraging habitats of the Gulf of Maine and Scotian Shelf during the seasons when abundance of C. finmarchicus was relatively low (spring, summer, fall). The drop in sightings is associated with extended duration of habitat use by North Atlantic right whales in Cape Cod Bay into the late spring and increased use of Southern New England waters and the Gulf of St. Lawrence in the spring and summer in the 2010s. Summertime declines in the 2010s for copepod abundances in the traditional foraging habitat ( e.g., Gulf of Maine) indicate that the increased use of the Gulf of St. Lawrence in more recent years is driven by a decline in prey in traditional foraging habitats rather than by an increase in prey in the new foraging habitat. Overall, while some patterns in seasonal habitat use remained consistent across all three decades, including the winter migration to the Southeast US calving ground and early spring foraging in Cape Cod Bay, there were notable differences in the seasonality and persistence of North Atlantic right whales in some foraging habitats across the study period which indicate that the North Atlantic right whale distribution patterns are shifting.

Van Parijs et al. (2023), provides 2 years of baseline data on cetacean species' presence, vessel activity, and ambient sound levels in the southern New England wind energy area. With eight species/families present in the area for at least 9 months of the year, this area represents an important habitat for cetaceans. Most species showed seasonality, with peak daily presence in winter (harbour porpoise, North Atlantic right, fin, and humpback whales), summer (sperm whales), spring (sei whales), or spring and fall/autumn (minke whales). Delphinids were continuously present and blue whales present only in January. The North Atlantic right whale was present year round with high presence in October through April.

Westell et al. (2024) collected baseline data from 2020 to 2022, with six passive acoustic recorders deployed in the vicinity of Nantucket Shoals and Cox's Ledge. Data were analyzed for sperm whale presence, and demographic composition was assessed using interclick intervals. Presence varied by site, season, and year. Sperm whales were detected year-round but the majority (78 percent) of days with acoustic occurrences were between May and August. Sound propagation tests were conducted at two sites and predicted detection ranges within 20-40 km indicate that sperm whales were likely in proximity to the WEA. These results provide a baseline for ongoing sperm whale presence, especially that of social groups which may be more sensitive to disturbance.

Moreover, new data also supports our inclusion of certain mitigation measures in the proposed and this final rule. For example, Crowe et al. (2023) discussed the use and importance of real-time data for detecting North Atlantic right whale. The shift in North Atlantic right whale habitat use motivated the integration of additional ways to detect the presence of North Atlantic right whales and passive acoustic detections of right whale vocalizations reported in near real-time became an increasingly important tool to supplement visual sightings. The proposed rule did include real-time and daily awareness measures and sighting communication protocols, NMFS evaluated these measures and added details for clarity or updated the reporting mechanisms, such as in the case of sighting an injured North Atlantic right whale. Davis et al. (2023) analyzed North Atlantic right whale individual upcalls from 2 years of acoustic recordings in southern New England which showed that North Atlantic right whale were detected at least 1 day every week throughout both years, with highest North Atlantic right whale presence from October to April. Within SNE, on average, 95 percent of the time North Atlantic right whales persisted for 10 days, and recurred again within 11 days. An evaluation of the time period over which it is most effective to monitor prior to commencing pile driving activities showed that with 1 h of pre-construction monitoring there was only 4 percent likelihood of hearing a North Atlantic right whale, compared to 74 percent at 18 h. Therefore, monitoring for at least 24 h prior to activity will increase the likelihood of detecting an up-calling North Atlantic right whale.

Since issuance of the proposed rule, a non-peer reviewed report on HRG survey noise has also been released (Rand et al., 2023). The measured data presented in Rand et al. (2023) are consistent with our evaluation of sound levels produced by HRG surveys ( i.e., received sound levels at the ranges measured) and vessels and do not change our assessments of potential impacts. The analysis of those data in the Rand et al. (2023) report, however, includes methodological issues and therefore does not support all of their conclusions.

Since the publication of the proposed rule, new scientific information has become available that provides additional insight into the sound fields produced by turbine operation (HDR, Inc., 2023; Holme et al., 2023). Recently, Holme et al. (2023) stated that Tougaard et al. (2020) and Stöber and Thomsen (2021) extrapolated levels for larger turbines and should be interpreted with caution since both studies relied on data from smaller turbines (0.45 to 6.15 MW) collected over a variety of environmental conditions. They demonstrated that the model presented in Tougaard et al. (2020) tends to overestimate levels (up to approximately 8 dB) measured to those in the field, especially with measurements closer to the turbine for larger turbines. Holme et al. (2023) measured operational noise from larger turbines (6.3 and 8.3 MW) associated with three wind farms in Europe and found no relationship between turbine activity ( i.e., power production, which is proportional to the blade's revolutions per minute) and noise level. However, it was noted that this missing relationship may have been masked by the area's relatively high ambient noise sound levels. Sound levels ( i.e., root-mean-square (RMS)) of a 6.3 MW direct-drive turbine were measured to be 117.3 dB at a distance of 70 m. However, measurements from 8.3 MW turbines were inconclusive as turbine noise was deemed to have been largely masked by ambient noise.

In addition, operational turbine measurements from the Coastal Virginia Offshore Wind pilot pile project indicated that noise levels from two, 7.8 m monopiles WTGs were higher when compared to Block Island wind farm, likely due to vibrations associated with the monopiles structure (HDR, Inc., 2023). We note that this updated information does not change our assessment for impacts of turbine operational sound on marine mammals. As described in the proposed rule, NMFS will require Avangrid to measure operational noise levels, however, is not authorizing take incidental to operational noise from WTGs.

In addition, recently, a National Academy of Sciences, Engineering, and Medicine (NASEM) panel of independent experts concluded that the impacts of offshore wind operations on North Atlantic right whales and their habitat in the Nantucket Shoals region (a key winter foraging habitat tens of kilometers to the east of the Project area) are uncertain due to the limited data available at this time and recognized what data is available is largely based on models from the North Sea that have not been validated by observations (National Academy of Sciences, 2023). The report also identifies that major oceanographic changes have occurred to the Nantucket Shoals region over the past 25 years and it will be difficult to isolate from the much larger variability introduced by natural and other anthropogenic sources (including climate change). This report is specific to the Nantucket Shoals region which is unlikely to be influenced by any long-term operational effects of the Project; however, the findings in the report align with those presented in the proposed rule. More recently, NMFS concluded ESA consultation on Federal actions associated with the Project, including NMFS's proposal to issue a 5-year rule to Avangrid and BOEM's approval of the Construction and Operation Plan (COP) which covers the 30 years of the Project's operation and subsequent decommissioning.

Similar to the discussion presented in the proposed rule, the BiOp stated the Project will produce a wind wake from operation of the turbines and that the foundations themselves will lead to disruptions in local conditions; the scale of these effects is expected to range from hundreds of meters and up to 1 km from each foundation and the changes in conditions may alter the distribution of nutrients, primary production, and plankton. The BiOp concluded it is not expected that the impacts to oceanic conditions resulting from the Project will affect the oceanographic forces transporting plankton into the area from the south and east; however, there may be effects on the distribution of plankton more locally. The construction and operation of the Project is not expected to alter this broad current pattern, and thus NMFS expects any alteration of the biomass of plankton in the region, and therefore, the total food supply, to be so small that adverse effects on ESA-listed species are not reasonably certain to occur.

Overall, there is no new scientific information regarding the general anticipated effects of OSW construction on marine mammals and their habitat that was not discussed in the proposed rule. The information and analysis regarding the potential effects on marine mammals and their habitat is incorporated by reference and included in the proposed rule is referenced and used for this final rule and is not repeated here; please refer to the proposed rule (88 FR 37606, June 8, 2023).

Estimated Take

As noted in the Changes from the Proposed to Final Rule section, changes to the estimated and allowable take ( i.e., take that may be authorized) for several species have been made since publication of the proposed rule based on new information from Avangrid, recommendations received during the public comment period, and the best available science. This section provides an estimate of the number of incidental takes that may be authorized through this rule, which will inform both NMFS' consideration of “small numbers” and the negligible impact determination. The analysis related to take incidental to HRG surveys, UXO/MEC detonation, and rare species is unchanged since the proposed rule. However, as described above in the Changes from the Proposed section, Avangrid re-evaluated the sound fields generated during foundation installation and corresponding exposure estimates which is further described in the foundation installation take section below. Takes allowed under this rule would primarily be by Level B harassment, as use of the acoustic sources ( i.e., impact and vibratory pile driving, drilling, UXO/MEC detonation, site characterization surveys) are expected to result in disruption of marine mammal behavioral patterns due to exposure to elevated noise levels. Impacts such as masking and TTS can contribute to behavioral disturbances. There is also some potential for auditory injury constituting Level A harassment to occur in select marine mammal species incidental to the specified activities ( i.e., impact pile driving and UXO/MEC detonation). For this action, this potential is largely limited to, though not exclusive to, mysticetes due to their hearing sensitivities and the nature of the activities. As described below, the larger distances to the PTS thresholds, when considering marine mammal weighting functions, demonstrate this potential. For mid-frequency hearing sensitivities, when thresholds and weighting and the associated PTS zone sizes are considered, the likelihood for PTS from the noise produced by the Project is less than that for mysticetes. The required mitigation and monitoring measures are expected to minimize the severity of the taking to the extent practicable. As described previously, no serious injury or mortality is anticipated or may be authorized incidental to the Project. Below, we describe how the take was estimated.

Generally speaking, we estimate take by considering: (1) acoustic thresholds above which NMFS believes the best available science indicates marine mammals will be behaviorally harassed or incur some degree of permanent hearing impairment (as well as impulse metric (Pascal-second) and peak sound pressure level thresholds above which marine mammals may incur non-auditory injury from underwater explosive detonations); (2) the area or volume of water that will be ensonified above these levels in a day; (3) the density or occurrence of marine mammals within these ensonified areas; and, (4) the number of days of activities. We note that while these basic factors can contribute to a basic calculation to provide an initial prediction of takes, additional information that can qualitatively inform take estimates is also sometimes available. Below, we describe the factors considered here in more detail and present the take estimates.

Marine Mammal Acoustic Thresholds

NMFS recommends the use of acoustic thresholds that identify the received level of underwater sound above which exposed marine mammals are likely to be behaviorally harassed (equated to Level B harassment) or to incur PTS of some degree (equated to Level A harassment). Thresholds have also been developed identifying the received level of in-air sound above which exposed pinnipeds would likely be behaviorally harassed. A summary of all NMFS' thresholds can be found at ( https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance ).

Level B harassment —Though significantly driven by received level, the onset of behavioral isturbance from anthropogenic noise exposure is also informed to varying degrees by other factors related to the source or exposure context ( e.g., frequency, predictability, duty cycle, duration of the exposure, signal-to-noise ratio, distance to the source), the environment ( e.g., other noises in the area) and the state of the receiving animals ( e.g., hearing, motivation, experience, demography, life stage, depth), and can be difficult to predict ( e.g., Southall et al., 2007, 2021; Ellison et al., 2012). Based on what the available science indicates and the practical need to use a threshold based on a metric that is both predictable and measurable for most activities, NMFS typically uses a generalized acoustic threshold based on received level to estimate the onset of behavioral harassment. NMFS generally predicts that marine mammals are likely to be behaviorally harassed in a manner considered to be Level B harassment when exposed to underwater anthropogenic noise above RMS pressure received levels (SPL) of 120 dB (re 1 μPa) for continuous ( e.g., vibratory pile driving, drilling) and above RMS SPL 160 dB re 1 μPa for non-explosive impulsive ( e.g., seismic airguns) or intermittent ( e.g., scientific sonar) sources (table 4). Generally speaking, Level B harassment take estimates based on these behavioral harassment thresholds are expected to include any likely takes by TTS as, in most cases, the likelihood of TTS occurs at distances from the source less than those at which behavioral harassment is likely. TTS of a sufficient degree can manifest as behavioral harassment, as reduced hearing sensitivity and the potential reduced opportunities to detect important signals ( e.g., conspecific communication, predators, prey) may result in changes in behavior patterns that would not otherwise occur.

Avangrid's construction activities include the use of continuous ( e.g., vibratory pile driving, drilling) and intermittent ( e.g., impact pile driving and HRG acoustic sources) sources; therefore, the 120 and 160 dB re 1 μPa (RMS) thresholds are applicable.

Level A harassment —NMFS' Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0; Technical Guidance, 2018) identifies dual criteria to assess auditory injury constituting Level A harassment to five different marine mammal groups based on hearing sensitivity as a result of exposure to noise from two different types of sources ( i.e., impulsive or non-impulsive sources). As dual metrics, NMFS considers onset of PTS constituting Level A harassment to have occurred when either one of the two metrics is exceeded ( i.e., metric resulting in the largest isopleth). The Project includes the use of impulsive and non-impulsive sources.

These thresholds are provided in table 4 below. The references, analysis, and methodology used in the development of the thresholds are described in NMFS' 2018 Technical Guidance, which may be accessed at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

Explosives Source Thresholds

Based on the best scientific information available, NMFS uses the acoustic and pressure thresholds indicated in table 5 to predict the onset of PTS and TTS during UXO/MEC detonation. For a single detonation (within a 24-hour period), NMFS relies on the TTS onset threshold to assess the likelihood for Level B harassment. The final rule is conditioned such that Avangrid would limit detonations to one per day and would be limited to daylight hours only.

Additional thresholds for non-auditory injury to lung and gastrointestinal (GI) tracts from the blast shock wave and/or onset of high peak pressures are also relevant (at relatively close ranges) as UXO/MEC detonations, in general, have potential to result in mortality and non-auditory injury (table 6). Marine mammal lung injury criteria have been developed by the U.S. Navy (DoN (U.S. Department of the Navy), 2017), and adopted by NMFS, and are based on the mass of the animal and the depth at which it is present in the water column due to blast pressure. This means that specific decibel levels for each hearing group are not provided and instead, the criteria are presented as equations that allow for incorporation of specific mass and depth values. The GI tract injury threshold is based on peak pressure. The modified Goertner equations below represent the potential onset of lung injury and GI tract injury (table 6).

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

Marine Mammal Density and Occurrence

In this section we provide the information about the presence, density, or group dynamics of marine mammals that will inform the take calculations. Depending on the species and as described in the take estimation section for each activity, take estimates may be based on the Roberts et al. (2023) density estimates, marine mammal monitoring results from HRG surveys, or average group sizes.

Habitat-based density models produced by the Duke University Marine Geospatial Ecology Laboratory and the Marine-life Data and Analysis Team, based on the best available marine mammal data from 1992 to 2022 obtained in a collaboration between Duke University, the Northeast Regional Planning Body, the University of North Carolina Wilmington, the Virginia Aquarium and Marine Science Center, and NOAA (Roberts et al., 2016a, 2016b, 2017, 2018, 2020, 2021a, 2021b, 2023), represent the best available science regarding marine mammal densities in the Project Area. More recently, these data have been updated with new modeling results and include density estimates for pinnipeds (Roberts et al., 2016b, 2017, 2018, 2023). Density data are subdivided into five separate raster data layers for each species, including: Abundance (density); 95 percent Confidence Interval of Abundance; 5 percent Confidence Interval of Abundance; Standard Error of Abundance; and Coefficient of Variation of Abundance.

The methods for calculating monthly, seasonal and annual densities have not changed since the proposed rule. For foundation installation, the width of the perimeter around the activity area used to select density data from the Roberts et al., 2022 models was based on the largest 10-dB attenuated exposure range (ER₉₅% ; the Level B harassment range) applicable to that activity. The applicant calculated monthly densities for each species using grid cells within the lease area and a perimeter around the lease area that represented the ER₉₅% ensonified area for each sound-producing activity. The mean density for each month was determined by calculating the unweighted mean of all 5 × 5 km grid cells partially or fully within the analysis polygon. Densities were computed monthly for the May-December period to coincide with proposed foundation pile driving activities. In cases where monthly densities were unavailable, annual mean densities were used instead. For cases with vibratory setting of piles followed by impact pile driving, and impact pile driving alone ( i.e., all pile driving scenarios), densities were calculated within buffered polygons of various ranges around the Lease Area perimeter. The following ranges were pre-selected: 10, 25, and 50 km. For each species, foundation type, and attenuation level, the most appropriate density perimeter was selected from this list. The range was selected using the 95th percentile exposure range (ER₉₅% ) for each case, using the next highest range. For example, if the ER₉₅% was 8.5 km, the 10 km perimeter would be used. In cases where the ER₉₅% was larger than 50 km, the 50-km perimeter was used. The 50 km limit is derived from studies of mysticetes that demonstrate received levels, distance from the source, and behavioral context are known to influence the probability of behavioral response (Dunlop et al., 2017).

For drilling, it was assumed that the activity would occur in three areas of interest: J1, M1, and M2 ( i.e., three modeled locations). The density perimeter was determined using the longest 10-dB attenuated 95th percentile acoustic range to the behavioral threshold (R₉₅% ) for all locations, rounded up to the nearest 5 km, and then applied around the entire lease area ( i.e., 7.1 km rounded up to 10 km). Monthly densities were calculated for each species as the average of the densities from all Roberts et al., 2022 model grid cells that overlap partially or completely with the area of interest. Cells entirely on land were not included, but cells that overlap only partially with land were included.

As described in the proposed rule, for UXO/MEC detonations, the applicant commissioned a UXO/MEC desktop study in which a comprehensive historic analysis of all activities which may have contributed to potential UXO/MEC presence in the project area. The applicant evaluated the risk of encountering the potential UXO/MECs and identified areas of moderate risk of UXO/MEC presence then commissioned an acoustic modeling study, as described in the proposed rule. As a result of this process, the largest SEL-based TTS-onset acoustic ranges across all hearing groups was applied it to the moderate UXO/MEC risk areas, resulting in a 14.1-km perimeter for the shallow water segment of the OECC and a 13.8-km density perimeter for the deep water segment of the OECC as well as the SWDA.

For HRG surveys, the applicant applied all grid cells within the survey corridor. No buffer was applied given the small distance to Level B harassment (<200 m) during surveys compared to the grid cell size in the Roberts et al., 2022 density models (5 × 5 km). To estimate densities for the HRG surveys occurring both within the Lease Area and within the export cable routes, the applicant mapped density data from Roberts et al. (2023) within the boundary of the Project Area using geographic information systems. The applicant then averaged maximum monthly densities (as reported by Roberts et al., 2023) by season over the survey duration (for winter (December through February), spring (March through May), summer (June through August), and fall (September through November)) within the HRG survey area. The maximum average seasonal density, for each species, was then carried forward in the take calculations (table 6).

For several marine mammal species, Roberts et al. (2023) does not differentiate by species and instead combines them into guilds. This is true for long-finned and short-finned pilot whales (pilot whale spp.), beaked whales, and harbor, harp, hooded, and gray seals (seals), where a pooled density by guild is the only value available from the data that is not partitioned by stock.

Below, we describe observational data from monitoring reports and average group size information, both of which are appropriate to inform take estimates for certain activities or species in lieu of density estimates.

For previous modeling efforts' marine mammal densities, for long- and short-finned pilot whales, the guild density from Roberts et al. (2016a, 2022b) was scaled by the relative stock sizes based on the best available abundance estimate from the 2023 SARs (Hayes et al., 2022). Similarly, densities were provided for seals as a guild consisting primarily of harbor and gray seals (Roberts et al., 2016a, 2022b), gray and harbor seal densities were scaled by relative 2023 SARs (Hayes et al., 2022) abundance. For the recently updated modeling efforts—vibratory setting followed by impact pile driving, impact pile driving alone, drilling, UXO/MEC detonations, and HRG when calculating exposures for individual pilot whale and seal species, the guild densities provided by Roberts et al. (2016a, 2022b) were scaled by the relative abundances of the species in each guild, using the best available estimates of local abundance, to get species-specific density estimates surrounding the Lease Area. In estimating local abundances, all distribution data from the two pilot whale species and three seal species were downloaded from the Ocean Biodiversity Information System (OBIS) data repository (available at https://obis.org/ ). After reviewing the available datasets, it was deemed that data available in OBIS in Rhode Island and Massachusetts waters are the best available for the three seal species because of their overlap with the Lease Area.

For seals, OBIS reported 86 observations of gray seals, 129 observations of harbor seals, and 93 observations of harp seals. Therefore, the proportions of 0.28 (86/308), 0.42 (129/308), and 0.30 (93/308) were used to scale the seals' guild densities for the three seal species, respectively. The best data available for pilot whales came from AMAPPS data in Rhode Island and Massachusetts waters. The proportions of 0.80 for long-finned and 0.20 for short-finned pilot whales were used (Palka et al., 2021).

For uncommon species, the predicted densities from the Roberts et al., 2022 models are very low and the resulting density-based exposure estimate is less than a single animal or a typical group size for the species. In such cases, densities were not used but the take request is based on the species' average group size (tables 10 and 11). When this occurred, the mean group sizes used to correct Level B harassment take estimates, as shown in tables 10 and 11, for modeled cetacean species were derived from AMAPPS data from 2010-2019 NE shipboard distance sampling surveys (Palka et al., 2021) or informed by data from 2018-2021 HRG surveys conducted near the project area (Vineyard Wind, 2018, 2020a, 2020c, 2021a). Mean group size was calculated as the number of individuals divided by the number of groups from table 6-5 of Palka et al. (2021), which summarizes the 2010-2019 AMAPPS NE shipboard distance surveys. Summer sightings (June 1 to August 31) were chosen for these calculations because many species were not observed during fall surveys, and surveys were not conducted during spring or winter. When site assessment survey data showed a larger mean group size than was shown by the AMAPPS data, the site assessment survey group size was applied to take calculations.

In cases where the exposure estimate was less than the mean group size, we predict that if one group member were to be exposed within the Level B harassment threshold, then it is reasonable to expect that all animals in the same group could be. Therefore, for species for which the annual number of predicted exposures above threshold was less than the mean group size, the annual number of expected takes was increased to one mean group size rounded up to the nearest integer. Correcting for group size for these species is used as a conservative measure to ensure that in the event of a close encounter with the species, a reasonably expected number of individuals ( i.e., average group size) is accounted for in the take request.

As described previously, density-based exposure calculations were not conducted for species considered rare in the project area. There are few to zero sightings of these species in the sources used above to calculate group size for the modeled species, so an alternative method had to be developed. Group size calculations for rare species used sighting data from the Ocean Biodiversity Information System database (OBIS, 2021). All records for each of the rare species were extracted from the OBIS database and then filtered to include only the area from approximately Cape Hatteras to the Gulf of Maine (35° N to 43° N) and from the coast (76° W) out to the continental shelf edge (66° W) to provide a more precise estimate of potential group size in the SWDA than would be expected using all OBIS records. The OBIS data were further filtered to remove stranding data, because the group size of stranded animals does not necessarily reflect the group size of free-ranging animals. The one exception to this was the hooded seal—all records of this species in this area from the OBIS database were of single, stranded individuals, and thus a group size of one was used. This number is likely reflective of any free-swimming hooded seal that would occur in the area because this is an Arctic species and only single vagrant animals would be expected. Finally, data from digital aerial surveys were filtered out of this larger dataset because, although useful in determining presence/absence, these data provide no information on group size. The “individualCount” variable in the OBIS data was used to calculate minimum, maximum, and average group sizes for these rare species (table 16 in the ITA application).

For many of these rare species, in particular the delphinids, maximum group sizes in OBIS can be in the hundreds or even up to thousands of animals. However, because these animals are rare in the project area, as it is not their preferred habitat, we think that they would be unlikely to form such large aggregations in this area and, further, it is unlikely that any such large aggregations would all swim with the small HRG Level B harassment zone. Thus, like with uncommon species, the average group size (rounded up to a whole number) based on the previously described observer data was used in the take calculations for these species instead of the OBIS data to refine the group sizes to what had been previously observed in similar surveys. Group sizes relevant to the project area can be informed by PSO sightings during site characterization surveys (tables 10 and 11). For example, white-beaked dolphins were recorded in both 2019 and 2020 during HRG surveys in this area (Vineyard Wind, 2019, 2020) with the sighting of white-beaked dolphins in 2019 consisting of 30 animals. Other rare species encountered in the survey area during previous HRG surveys include false killer whales in 2019 (5 individuals) and 2021 (1 individual) (Vineyard Wind, 2020c, 2020b) and killer whales in 2022 (2 individuals; data not yet submitted). For these species the take estimates use the average observed group size from PSO sightings.

Additional detail regarding the density and occurrence as well as the assumptions and methodology used to estimate take for specific activities is included in the activity-specific subsections below and in Section 6.1 of the ITA application. Average group sizes used in take estimates, where applicable, for all activities are provided in tables 10 and 11.

Tables 7, 8, and 9, below demonstrate all of the densities used in the exposure and take analyses. Densities differed depending on the types of piles installed and manner of take being assessed given the large spatial extent differences between ER₉₅% for Level A harassment and Level B harassment. Tables 10 and 11 show the average marine mammal group sizes calculated based on the methods described above.

Modeling and Take Estimation

Avangrid estimated take using both sophisticated sound and animal movement modeling to account for the movement and behavior of marine mammals and their exposure to the underwater sound fields produced during foundation impact and vibratory pile driving, as described below. Avangrid estimated the potential for harassment from drilling, HRG, and UXO/MEC detonations using a simplified “static” method wherein the take estimates are the product of density, ensonified area above the NMFS defined threshold ( e.g., unweighted 160 dB SPLrms) levels, and number of days of installation. Animal movement modeling was not conducted for drilling, HRG, and UXO/MEC detonations.

In some cases, the exposure estimates based on either the animal movement modeling or static methods described above directly informed the amount of take requested; in other cases, adjustments were made based on previously collected monitoring data or average group size as described above. In all cases, Avangrid requested, and NMFS may authorize, take based on the highest amount of exposures estimated from any given method.

Below we present the take estimate methodologies associated with each activity.

WTG and ESP Foundation Installation

WTG and ESP installation activities have the likelihood to result in harassment of marine mammals from pile driving and drilling.

Since the proposed rule, the applicant refined the modeling methodology for impact pile driving and vibratory pile setting (section 1.7 in the January 2024 Application Update). In the original modeling (impact pile driving for the July 2022 LOA application), JASCO modeled impact pile driving source characteristics using an energy-based parabolic equation (PE) model (JASCO's Marine Operations Noise Model (MONM)) to compute the near-field equivalent source before long range propagation. In this update, JASCO's Full-Wave PE RAM model (FWRAM) was used to compute the near-field equivalent source before the long-range propagation was computed (also using FWRAM). Using FWRAM over MONM is an improvement because it calculates full synthetic pressure waveforms (in the time domain), as opposed to summed energy independent of time. Like MONM, FWRAM is range dependent for range-varying marine acoustic environments and takes environmental inputs (bathymetry, water sound speed profile, and seabed geoacoustic profile) into account. FWRAM computes pressure waveforms via Fourier synthesis of the modeled acoustic transfer function in closely spaced frequency bands, and employs the array starter method to accurately model sound propagation from a spatially distributed source (MacGillivray and Chapman, 2012). Ultimately, little difference was observed between the prior sound fields with near-field equivalents computed using MONM versus the current modeling with FWRAM but FWRAM is a more accurate model as it allows direct calculation of peak and RMS sound pressure levels. Both models use a wide-angle parabolic equation solution to the acoustic wave equation (Collins, 1993), based on a version of the US Naval Research Laboratory's Range-dependent Acoustic Model (RAM), which has been modified to account for a solid seabed (Collins, 1993; Zhang and Tindle 1995).

The practical spreading loss approach described for vibratory pile driving in the proposed rule has been replaced with acoustic modeling, similar to the refined impact pile driving methodology. A quantitative acoustic assessment was conducted by Avangrid of the potential impacts to marine mammals from vibratory pile setting followed by impact pile driving activity during installation. As vibratory pile driving will be used on the same foundations subject to impact pile driving (sequentially not concurrently), acoustic modeling was completed for vibratory setting of piles followed by impact pile driving, and exposures were modeled using animal movement modeling as described in the impact pile driving model. One second long vibratory forcing functions were computed for the 12 and 13 m monopile and the 4-m jacket foundations, using GRL's Wave Equation Analysis (GRLWEAP, 2010; GRLWEAP Pile Dynamics, 2010). Non-linearities were introduced to the vibratory forcing functions based on the decay rate observed in data measured during vibratory pile driving of smaller diameter piles (Quijano et al., 2017). The resulting forcing functions serve as inputs to JASCO's pile driving source model (PDSM) used to estimate an equivalent acoustic source represented by a linear array of monopoles evenly distributed along the pile. Acoustic propagation modeling used FWRAM that combine the outputs of the source model with the spatial and temporal environmental context ( e.g., location, oceanographic conditions, and seabed type) to estimate sound fields. Unchanged from the proposed rule, NMFS notes that no hammer parameters were available for either a 5,000 or 6,000 kJ hammer for use in GRLWEAP 2010; Avangrid modeled energies of the 5,500 kJ hammer were scaled using their stroke length to represent the effect of the forcing functions for the two different hammers approximated.

Avangrid also updated source and propagation modeling approaches associated with estimating impacts from drilling. The proposed rule assumed an unattenuated source level of 193.3 dB re 1 μPa (as estimated by Austin et al. (2018) and therefore, assuming 10 dB of attenuation as sound attenuation measures were proposed to be required, applied a 183.3 dB SPL source level to the analysis. Avangrid had applied a practical spreading loss model (15logR) to that source level, resulting in a 16.6-km distance to NMFS 120 dB SPL Level B harassment threshold. For this final rule, Avangrid modeled drilling noise at the source and conducted more sophisticated propagation modeling. To model drilling, the three representative source levels estimated by Austin et al. (2018) for the 10-32,000 Hz band were averaged with an average broadband level of 191.6 dB re 1 μPa2·s m2. These modeling locations were selected as they represent the range of water depths in the Lease Area. MONM was used to predict SEL and SPL sound fields up to 1 kHz at a representative location near the proposed drilling sites considering the influence of bathymetry, seabed, water sound speed, and water attenuation. From 1 to 25 kHz, the BELLHOP ray tracing model (Porter and Liu, 1994) was used to predict sound fields at the same representative location using from 2512 to 5012 geometric beams, increasing the beam coverage with frequency. The total sound energy transmission loss was computed at the center frequencies of decidecade bands as a function of range and depth from the source. MONM-BELLHOP accounts for sound attenuation due to energy absorption through ion relaxation and viscosity of water in addition to acoustic attenuation due to reflection at the medium boundaries and internal layers (Fisher and Simmons 1977). The former type of sound attenuation is important for frequencies higher than 5 kHz and cannot be neglected without noticeably affecting the model results. The drill was represented as a point source in the mid-water column at each site. The mid-water depth is a conservative representation of the noise source across the drill bit. The acoustic field in three dimensions was generated by modeling two-dimensional (2-D) vertical planes radially spaced at 2.5° in a 360° swath around the source ( N × 2-D). Composite broadband received SEL were computed by summing the received decidecade band levels across frequency and taking the maximum-over-depth. Overall, the average source levels per decidecade band center frequency were used in MONM to predict SEL and SPL sound fields up to 1 kHz, and a BELLHOP ray tracing model (Porter and Liu 1994) was used from 1-32 kHz, at a representative location near the proposed drilling sites considering the influence of bathymetry, seabed, water sound speed, and water attenuation. The modeled unweighted SPL levels at 750 m were 135.25-136.33 dB re 1 μPa during the summer. The corresponding unweighted cumulative SEL levels at 750 m are 185.07-185.24 dB re 1 μPa² ·s during the summer.

Similar to the proposed rule, modeling assumed that drilling activity could occur for a full 24 hours during any given day although it is not expected that drilling would be required up to 24 hours, More details on the drilling modeling methods and assumptions can be found in more detail in the January 2024 Drilling Technical Memo on our website ( https://www.fisheries.noaa.gov/action/incidental-take-authorization-park-city-wind-llc-construction-new-england-wind-offshore-wind ).

JASCO conducted exposure modeling for impact driving in the same manner as described in the proposed rule for impact driving. For this final rule, exposure modeling was also conducted for vibratory pile driving (versus the static method applied in the proposed rule). JASCO's Animal Simulation Model Including Noise Exposure (JASMINE) was used to estimate the closest approach ranges within which 95 percent of simulated animals (animats) were exposed above the relevant regulatory-defined thresholds for injury and behavioral response for marine species that may be near, or in the vicinity of, the proposed foundation piling operations (impact and vibratory). Therefore, JASMINE was used to estimate the probability of exposure of animals to sound arising from impact and vibratory pile driving operations during construction of the Project. Sound exposure models such as JASMINE use simulated animals (animats) to sample the predicted 3-D sound fields with movement rules derived from animal observations. The parameters used for forecasting realistic behaviors ( e.g., diving, foraging, aversion, and surface times) are determined and interpreted from marine species studies ( e.g., tagging studies) where available, or reasonably extrapolated from related species (appendix G.2, Hydroacoustic Report January 2024).

The predicted sound fields were sampled by the model receiver in a way that real animals are expected to by programming animats to behave like marine species that may be present near the Project. The output of the simulation is the exposure history for each animat within the simulation. An individual animat's sound exposure level is summed over a specified duration, ( i.e., 24 hours (appendix H Hydroacoustic Report January 2024)), to determine its total received acoustic energy (SEL) and maximum received PK and SPL. Received levels are then compared to the threshold criteria described in Section 2.4 (Hydroacoustic Report January 2024) within each analysis period. Appendix H of the Hydroacoustic Report January 2024 provides a fuller description of animal movement modeling and the parameters used in the JASMINE simulations. Due to shifts in animal density and seasonal sound propagation effects, the number of animals predicted to be impacted by the pile driving operations is sensitive to the number of foundations installed during each month.

The animal movement modeling assumed 60 minutes of vibratory setting of piles for all pile types and installation schedules. For piling of monopile foundations, the model assumed 15 minutes between vibratory and impact pile driving to switch equipment. A strike rate of 30 strikes per minute for the 5,000 kJ hammer scenarios, 27.6 strikes per minute for the 6,000 kJ hammer 13 m monopile scenarios, and 25 strikes per minute for the 6,000 kJ hammer 12 m monopile scenarios was used. The model assumed 30 minutes between foundation installation when more than one foundation was installed per day.

For jacket foundations, the number of strikes required to drive each pile as provided by Avangrid is a conservative estimate, in that it is likely to be an overestimate of the actual number of strikes required. The animal movement modeling is based on exposure levels in a 24 hour period to capture 24-hour cumulative metrics ( i.e., SEL), so pile installation is constrained to fit within 24 hours. To accommodate the high number of strikes for jacket foundations within a 24-hour period, a strike rate of 30 per minute was used to model cases where 4 pin piles were installed in one day. Additionally, the time between pile installation each day was 15 minutes between vibratory and impact pile driving to switch equipment and 15 minutes between foundation installations.

When evaluating the potential for injury, the total received acoustic energy (SEL) over a given time period (24 hour) is needed. Vibratory setting of piles followed by impact pile driving may occur for the installation of both monopile and jacket foundations. Although the potential to induce hearing loss is low during vibratory driving, it does introduce sound into the water and must be considered as part of the total received acoustic energy. For this reason, the combined sound energy from vibratory and impact pile driving was computed in the 2024 January Application Update from Avangrid. The PTS onset SEL thresholds are lower for impact piling than for vibratory piling (section 2.4 Hydroacoustic Report January 2024), so when estimating animats exposed to potentially injurious sound levels, the lower thresholds were applied to the total received sound energy level from both sources. Full details on the acoustic model can be found on our website in the Hydroacoustic Report January 2024 at https://www.fisheries.noaa.gov/action/incidental-take-authorization-park-city-wind-llc-construction-new-england-wind-offshore-wind .

As previously described, JASCO integrated the results from acoustic source and propagation modeling into an animal movement model to calculate exposure ranges for 17 marine mammal species considered common in the project area. The resulting ranges represent the distances at which marine mammals may incur Level A harassment ( i.e., PTS). The exposure ranges also influence the development of mitigation and harassment zone sizes. The first year of Schedule A includes the potential installation of 13-m monopiles using a 6,000 kJ hammer. In the proposed rule and unchanged in this final rule, this specific configuration was not modeled beyond acoustic source modeling because initial source modeling showed minimal difference between the 12-m and 13-m monopiles (see table 12 in the proposed rule (88 FR 37606, June 8, 2023)). Therefore, Avangrid modeled the 12-m monopile with 6,000 kJ hammer energy which was assumed to be a reasonable replacement for the 13-m. Avangrid assumed that all phase 2 foundations are jackets as their modeling results found that jacket foundations are the most impactful in terms of the Level A cumulative sound exposure metric. Thus, the assumption of all jacket foundations provide an envelope for an up to 13-m monopile installed with a 5,000 or 6,000 kJ hammer. Tables 13 and 14 provide exposure ranges for impact pile driving 12-m and 13-m monopiles and 4-m pin piles (jacket foundations), assuming 10 dB of attenuation. Table 15 provides Level A harassment exposure ranges for vibratory pile driving followed by impact pile driving of 12-m and 13-m monopiles, assuming 10 dB of attenuation. Table 16 provides Level B harassment exposure ranges for vibratory pile driving followed by impact pile driving of 12-m and 13-m monopiles, assuming 10 dB of attenuation. Table 17 provides exposure ranges for vibratory pile driving followed by impact pile driving of 4-m pin piles (jacket foundations), assuming 10 dB of attenuation.

Animat exposure modeling was not conducted for drilling. Instead, exposures were calculated for one day of drilling, modeled at three site locations. Exposures were calculated for each of these locations individually and for the maximum potential exposures using the maximum ensonified area for each threshold. Exposures were estimated using the monthly animal densities from May to December.

JASCO also calculated acoustic ranges which represent distances to NMFS's harassment isopleths independent of movement of a receiver. Acoustic ranges are a better representation of distances to NMFS's instantaneous harassment thresholds ( i.e., PTS dB peak, and Level B harassment) and can also be used for PTS dB SEL when animal movement modeling is not conducted. As described previously, the distances to the PTS dB SEL threshold are likely an overestimate as it assumes an animal remains at the distance for the entire duration of pile driving. Presented below are the distances to the PTS (dB peak) threshold and Level B harassment (SPL) thresholds for drilling.

Acoustic modeling assumed that drilling activity could occur for a full 24 hours during any given day. Although drilling is not expected to be required for 24 hours, all modeling assumed 24 hours of drilling to provide the most conservative estimate. Exposures were calculated for one day of drilling. Drilling was modeled at each of the three model site locations (J1, M1, M2). Exposures were calculated for each of these locations individually and also for the maximum potential exposures using the maximum ensonified area for each threshold. Exposures were estimated using the monthly animal densities from May to December. Maximum predicted injury exposures were <0.01 for modeled marine mammals (see appendix K of the Hydroacoustic Report January 2024), where ranges to injurious thresholds are <200 m for all species.

Acoustic ranges to the Level A harassment threshold and Level B harassment thresholds are in tables 18 and 19, respectively. Mean monthly density estimates for pile driving and drilling, in consideration of the applicable perimeter for each type, are provided in tables 7, 8, and 9.

Unchanged from the proposed rule, to estimate take from foundation installation activities, Avangrid used two pile installation construction schedules (tables 20 and 21). Overall, Construction Schedule A (Schedule A) assumes 52 days of foundation installation activities would occur between May and December in 2026 (year 2) to install 89 monopiles and 2 jacket foundations and 35 days of foundation installation activities would occur in 2027 (year 3) to install 18 monopiles and 24 jacket foundations. As previously described, Park City accounted for 133 piles to be installed in its modeling despite a maximum of 132 foundations actually being installed. In total, based on Schedule A, 87 days of foundation installation activities would occur over 2 years to complete the Project. Construction Schedule B (Schedule B) assumes 38 days of foundation installation activities would occur between May and December in 2026 (year 2) to install 55 monopiles and 3 jacket foundations, 53 days of foundation installation activities would occur in 2027 (year 3) to install 53 jackets, and 22 days of foundation installation activities would occur in 2028 (year 4) to install 22 jackets. In total, based on Schedule B, 113 days of foundation installation activities would occur over 3 years to complete the Project.

Due to the extended duration of Schedule B, the total amount of Level B harassment from foundation installation activities is greater than Schedule A over the 5-year effective period of the final rule. The total 5-year take by Level B harassment in this final rule is therefore generated based on Schedule B. However, annual take estimates assume the yearly worst case scenario exposures for each species for each year from either Construction Schedule A or B. That is, annual take by Level B harassment due to foundation installation activities may use either Schedule A or B, whichever was more. As previously described, Park City accounted for 133 piles to be installed in its modeling despite a maximum of 132 foundations actually being installed to complete the Project.

Avangrid considered three foundation installation techniques when estimating take: impact pile driving, vibratory pile driving followed by impact pile driving, and drilling (to break up any obstacles should the pile encounter obstructions). Of these, Level A harassment (PTS) has the potential to occur from impact pile driving only. As shown in table 18, vibratory pile driving and drilling produce very small Level A harassment zone sizes that consider static receivers over the duration of the time period considered in the model. For vibratory pile driving, the duration considered was relatively short (60 minutes); however, this represents vibratory pile driving over two piles in which there are several hours in between events and the resulting distances are comparatively small (table 18). Moreover, the implementation of clearance and shut down zones would further reduce the potential for PTS from these activities. Therefore, Avangrid has concluded, and NMFS agrees, the potential for PTS to occur from vibratory pile driving or drilling is discountable. For this reason, Avangrid carried forward the PTS exposure estimates from impact pile driving and no take by Level A harassment was considered for vibratory pile driving or drilling. The maximum take by Level A harassment that may be authorized under this final rule from the foundation activities ( i.e., impact pile driving) is in table 24.

To estimate the amount of Level B (behavioral) harassment that may occur incidental to foundation installation, Avangrid considered all three installation methods. As described above, Avangrid conducted exposure modeling to estimate the number of exposures that may occur from pile driving. The results of the exposure modeling and amount of take Avangrid requested from this activity is provided in the January 2024 Application Update. Avangrid calculated take considering drilling for 48 foundations over 48 days for both Schedule A and Schedule B. In the proposed rule and unchanged in the final rule, Avangrid applied a more traditional approach to estimate take from drilling wherein:

Take = density × area ensonified × number of days of activity

The resulting monthly and annual take can be found in the January 2024 Application Update.

To avoid overestimating take, the amount of take derived when considering impact driving, vibratory driving, and drilling independently were not summed to produce the amount of annual take Avangrid requested. Instead, Avangrid appropriately deducted the take from drilling when vibratory pile driving and drilling would occur on the same day. This is because the area for vibratory pile driving is much larger than drilling (table 19) and the amount of take by Level B harassment estimated for vibratory pile driving adequately covers potential take from drilling activities. However, because take from pile driving was modeled based on the number of piles while drilling takes were based on the number of days of activity, Avangrid added the take estimates from pile driving all piles to the take estimates from vibratory drilling (with the appropriate discounting) to produce their annual and total take requests.

The amount of Level B harassment take that may be authorized by this final rule represents the amount of take from impact pile driving on days when only impact pile driving could occur plus the amount of take from vibratory pile driving or drilling on the days that either of those activities could occur to avoid double counting.

Table 24 provides the annual take by Level B harassment calculated from pile driving for both Schedule A and, separately, Schedule B. For ease of reference, the construction schedules have been included below in tables 20-21. Table 25 identifies the amount of take for drilling foundation installation activities after removing drilling takes when drilling would occur on the same day as vibratory pile driving (to avoid double counting). The annual take amounts represent the highest value between both Schedule A and Schedule B while the maximum 5-year take estimates represent the sum of take calculated for each year in Schedule B (as Schedule B has the highest amount of take associated). NMFS retained Avangrid's request for Level A harassment from all impact pile driving activities as no Level A harassment from vibratory pile driving or drilling is anticipated (table 24). Table 26 identifies the amount of take for all foundation installation activities combined that was carried forward in the take tables for this final rule.

UXO/MEC Detonations

Avangrid may detonate up to 10 UXO/MECs within the project area with no more than six in 2025 (year 1) and four in 2026 (year 2); no more than one detonation per 24-hour period would occur. Avangrid adopted the U.S. Navy's charge weight bins (E4, E6, E8, E10, and E12) to determine potential impacts to marine mammals from UXO/MEC detonation. As described in the proposed rule, Avangrid applied modeling results from the Revolution Wind project to its analysis. This modeling evaluated the effects thresholds for TTS, PTS, non-auditory injury, and mortality based on the appropriate metrics: (1) peak sound pressure level; (2) weighted cumulative SEL; and (3) acoustic impulse. Charge weights of 2.3 kg (5.1 pounds (lbs)), 9.1 kg (20.1 lbs), 45.5 kg (100.3 lbs), 227 kg (500 lbs), and 454 kg (1,000.9 lbs), which is the largest charge the Navy considers for the purposes of its analyses (see the Description of the Specified Activities section in the proposed rule), were modeled to determine the ranges to mortality, gastrointestinal injury, lung injury, PTS, and TTS thresholds. The exact type and net explosive weight of UXO/MECs that may be detonated are not known at this time. However, based on the results of a UXO/MECs desktop study (Mills, 2021), Avangrid does not expect that 10 of the largest charge weight (bin E12) UXO/MECs will be present, but a combination of different sizes. For the 10 UXO/MECs, the model estimated the E12 charge weight with 2 detonations at 12 m, 3 detonations at 20 m, 3 detonations at 30 m, and 2 detonations at 40 m.

Mortality and non-auditory injury to lung and gastrointestinal organs were considered in the modeling study (Hannay and Zykov, 2022). As described in the proposed rule, peak pressure and acoustic impulse levels and effects threshold exceedance zones depend only on charge weight, water depth, animal mass, and submersion depth. The maximum distance to gastrointestinal injury (1 percent of exposed animals) due to peak pressure for detonating an E12-size UXO/MEC at all sites assuming 10 dB of attenuation is 125 m (Hannay and Zykov, 2022). The maximum distance modeled to the onset of lung injury due to detonating an E12-size UXO/MEC assuming 10 dB of attenuation is 237 m for baleen whales, 330 m for pilot and minke whales, 448 m for beaked whales, 606 m for delphinids, Kogia, and pinnipeds, and 648 m for harbor porpoise (table 27). Assuming 10 dB of attenuation, the impulse-based maximum distance to the onset of mortality is 353 m (porpoises) (table 27).

Avangrid will be required to conduct extensive monitoring using both PSOs and PAM operators and clear an area of marine mammals prior to detonating any UXO/MEC. Given that Avangrid will be employing multiple platforms to visually monitor marine mammals as well as conducting PAM and must only detonate UXO/MECs during daylight hours, it is reasonable to conclude that marine mammals will be reliably detected within approximately 660 m of the UXO/MEC being detonated and mortality or non-auditory injury is not likely to occur. As described below, in consideration of the distances to the associated thresholds and the implementation of the required mitigation and monitoring measures, Avangrid did not request and NMFS does not anticipate and may not authorize take by mortality or non-auditory injury. All modeling results, including mortality and non-auditory injury, can be found in appendix A for Avangrid's ITA application (Hannay and Zykov, 2022), as found on NMFS' website ( https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable ).

Distances to PTS and TTS thresholds for all UXO/MEC charge weights were also calculated by Avangrid. In the proposed rule, we only described the distances to thresholds for the largest E12 charge weight. However, in the event that Avangrid will be able to identify and mitigate at the relevant distances for each specific charge weight, we have incorporated the maximum values for each charge weight size herein. It is not currently known how easily the size and charge weights of UXO/MECs can be identified in the field. Avangrid must demonstrate to NMFS that it is able to accurately identify charge weights in the field prior to detonation otherwise the largest charge weight, E12, will be assumed and the appropriate associated mitigation and monitoring measures implemented. Tables 28 and 29 contain the maximum (ER₉₅% ) modeled distances by Hannay and Zykov (2022) to PTS and TTS thresholds during UXO/MEC detonation for each charge weight bin.

To estimate the maximum ensonified zones that could result from UXO/MEC detonations, the area distances in Li and Koessler (2022) table J-5 were multiplied by the highest monthly species density in the deepwater OECC segment and the SWDA for the 20-45 m depths, and by the highest monthly species density in the shallow water OECC segment for the 12 m depth. The result of the areas multiplied by the densities were then multiplied by the number of UXO/MECs estimated at each of the depths to calculate total estimated exposures. To calculate potential marine mammal exposures, Avangrid assumed all charge weights belong in the largest E12 class; therefore, the largest acoustic range (R₉₅%_t; assuming 10 dB of attenuation) to PTS and TTS thresholds of a E12 UXO/MEC charge weight were used as radii to calculate the area of a circle ( pi × r ² ; where r is the range to the threshold level) for each marine mammal hearing group. The ensonified area distances were multiplied by the highest monthly species density in the deepwater OECC segment and the lease area (SWDA) for the 20-45 m depths, and by the highest monthly species density in the shallow water OECC segment for the 12 m depth (using a 14.1-km buffer) and the combined deepwater segment of the OECC and SWDA (20 m-45 m depths; using a 13.8-km buffer).

As a conservative approach, the month with the highest density among the areas of interest for each species was carried forward to the exposure calculations ( i.e., assumed all UXO/MECs would be detonated in the month with the greatest average monthly density). In some cases where monthly densities were unavailable, annual densities were used instead for some species ( i.e., blue whales, pilot whale spp.). Additionally, the pilot whale guild, harbor seals, gray seals, and harp seals were scaled by relative abundance following the same approach previously described. The resulting maximum density was multiplied by the number of UXO/MECs estimated at each of the depths to calculate total estimated exposures. Table 30 provides the maximum species-specific densities for the Project and resulting take calculations using the described approach. As described above, Avangrid based the amount of take requested for authorization on the number of exposures estimated assuming 10 dB of attenuation using a NAS, NAS would be required during all detonations.

The likelihood of marine mammal exposures above the PTS threshold is low, especially considering the instantaneous nature of the acoustic signal and that Avangrid would conduct extensive monitoring, delaying a detonation should a marine mammal be within the PTS distances. However, some species, such as harbor porpoise and seals are difficult to detect given the relatively large distances to the high-frequency cetacean Level A harassment (PTS, SEL_cum) isopleth applicable to harbor porpoises and the difficulty detecting this species at sea, Avangrid requested, and NMFS may authorize, takes by Level A harassment of harbor porpoise from UXO/MEC detonations. Similarly, seals are difficult to detect at longer ranges, and although the distance to the phocid hearing group SEL PTS threshold is not as large as those for high-frequency cetaceans, it may not be possible to detect all seals within the PTS threshold distances even with the required monitoring measures. Therefore, Avangrid requested and NMFS may authorize under this rulemaking take by Level A harassment of gray seals, harbor seals, and harp seals incidental to UXO/MEC detonation. Given the extensive monitoring, it is likely that all PTS of large whales would be avoided. However, in the unexpected circumstance that a large whale other than a North Atlantic right whale ( i.e., fin whale, humpback whale, minke whale, sei, and sperm whales) is missed during monitoring, Avangrid requested, and NMFS may authorize, a very small amount of Level A harassment incidental to UXO/MEC detonation. Due to the mitigation and monitoring measures required specifically for North Atlantic right whales ( e.g., clearance zone is “any distance”; table 36), it is unlikely that North Atlantic right whales will be missed during monitoring. Therefore, take by Level A harassment is not expected to occur; Avangrid did not request and NMFS is not authorizing take by Level A harassment of North Atlantic right whales. Given that North Atlantic right whales are reported frequently, Avangrid would be required to monitoring the sighting network for this species, and conduct acoustic monitoring, it is not expected that a North Atlantic right whale would be missed during monitoring and therefore, Level A harassment of this species is not requested and NMFS may not authorize incidental to UXO/MEC detonation.

HRG Surveys

Avangrid's planned HRG survey activity includes the use of impulsive sources ( i.e., boomers and sparkers) that have the potential to harass marine mammals. The acoustic sources expected to result in marine mammal harassment, as defined under the MMPA, are provided in table 3 of the proposed rule (88 FR 37606, June 8, 2023) and remain unchanged in this final rule. If authorized, takes will be by Level B harassment only in the form of disruption of behavioral patterns for individual marine mammals resulting from exposure to noise from certain HRG acoustic sources. Based primarily on the characteristics of the signals produced by the acoustic sources planned for use, Level A harassment is neither anticipated, even absent mitigation, nor planned to be authorized. Please see Avangrid's application for details of a quantitative exposure analysis ( i.e., calculated distances to Level A harassment isopleths and Level A harassment exposures). Further, there is no evidence to suggest that serious injury or mortality is a potential outcome of exposure to HRG survey sources, and none is anticipated.

Therefore, the potential for Level A harassment from HRG surveys is not evaluated further in this document. Avangrid did not request, and NMFS may not authorize, take by Level A harassment incidental to HRG surveys. No serious injury or mortality is anticipated to result from HRG survey activities.

Specific to HRG surveys, in order to better consider the narrower and directional beams of the sources, NMFS has developed a tool for determining the sound pressure level (SPL_rms) at the 160-dB isopleth for the purposes of estimating the extent of Level B harassment isopleths associated with HRG survey equipment (NMFS, 2020). This methodology incorporates frequency-dependent absorption and some directionality to refine estimated ensonified zones. Avangrid used NMFS' methodology with additional modifications to incorporate a seawater absorption formula and account for energy emitted outside of the primary beam of the source. For sources that operate with different beamwidths, the maximum beam width was used, and the lowest frequency of the source was used when calculating the frequency-dependent absorption coefficient.

The isopleth distances corresponding to the Level B harassment threshold for each type of HRG equipment with the potential to result in harassment of marine mammals were calculated per “NOAA Fisheries' Interim Recommendation for Sound Source Level and Propagation Analysis for High Resolution Geophysical Sources.” The distances to the 160-dB RMS re 1 μPa isopleth for Level B harassment are presented in table 31. Please refer to appendix I in Li and Koessler (2022) of the LOA application for a full description of the methodology and formulas used to calculate distances to the Level B harassment threshold.

The survey activities that have the potential to result in Level B harassment (160 dB SPL) include the noise produced by Applied Acoustics AA251 Boomer or GeoMarine Geo Spark 2000 (400 tip) (table 31), of which the Applied Acoustics AA251 Boomer results in the greatest calculated distance to the Level B harassment criteria at 178 m (584 ft). Avangrid has applied the estimated distance of 178 m (584 ft) to the 160 dB_RMS90 percent re 1 μPa Level B harassment criteria as the basis for determining potential take from all HRG sources. All noise-producing survey equipment is assumed to be operated concurrently. Three vessels are assumed to be operating concurrently.

The basis for the take estimate is the number of marine mammals that would be exposed to sound levels in excess of the Level B harassment threshold (160 dB). Typically, this is determined by estimating an ensonified area for the activity, by calculating the area associated with the isopleth distance corresponding to the Level B harassment threshold. This area is then multiplied by marine mammal density estimates in the Project Area and then corrected for seasonal use by marine mammals, seasonal duration of Project-specific noise-generating activities, and estimated duration of individual activities when the maximum noise-generating activities are intermittent or occasional.

The total area ensonified was estimated by considering the distance of the daily vessel track line (determined using the estimated average speed of the vessel and the 24-hour operational period within each of the corresponding survey segments) and the longest horizontal distance to the relevant acoustic threshold from an HRG sound source (full formula in section 6.6 of the ITA application). Using the larger distance of 178 m (164 ft)) to the 160 dB_{RMS90 percent} re 1 μPa Level B harassment isopleth (table 31), the estimated daily vessel track of approximately 80 km (49.7 mi) per vessel for 24-hour operations, inclusive of an additional circular area to account for radial distance at the start and end of a 24-hour cycle, estimates of the total area ensonified to the Level B harassment threshold per day of HRG surveys were calculated (table 31).

Exposure calculations assumed that there would be 25 days of HRG surveying per year over each of the 5 years. As described in the ITA application, density data were mapped within the boundary of the Project Area using geographic information systems, these data were updated based on the revised data from the Roberts et al. (2022) model. Because the exact dates of HRG surveys are unknown, the highest density month for each species was used and carried forward in the take calculations (table 32).

The calculated exposure estimates based on the exposure modeling methodology described above were compared with the best available information on marine mammal group sizes. Group sizes used for HRG take estimates were the same as those used for impact pile driving take estimation (section 6.1.2 in the ITA application). Avangrid also used data collected by PSOs on survey vessels operating during HRG surveys in 2020-2021 from their nearby Vineyard Wind project area. It was determined that the calculated number of potential takes by Level B harassment based on the exposure modeling methodology above may be underestimates for some species and therefore warranted adjustment using group size to ensure conservatism in the take numbers NMFS may authorize. Despite the relatively small modeled Level B harassment zone (178 m) for HRG survey activities, it was determined that adjustments to the requested numbers of take by Level B harassment for some dolphin species was warranted to be conservative (see below).

For certain species for which the density-based methodology described above may result in potential underestimates of take and Avangrid's PSO sightings data were relatively low, adjustments to the exposure estimates were made based on the best available information on marine mammal group sizes to ensure conservatism. For species with densities too low in the region to provide meaningful modeled exposure estimates ( i.e., rare species), the take request is based on the average group size (table 11). For species not considered rare in the Project Area, but AMAPP data or Avangrid PSO data show a higher group size level than the Roberts et al. (2022) model, then the takes by Level B harassment requested for authorization were adjusted to one group size per day of HRG surveys (table 32).

For species considered rare but that still have the small potential for occurrence in the Project area, takes by Level B harassment during HRG surveys were requested by Avangrid. This occurred for white-beaked dolphin, killer whale, and false killer whale. Avangrid based their takes requested for authorization on these species by using one group size per year in 3 of 5 years for species. Group sizes used were based on PSO observations during previous HRG surveys.

Total Authorized Take Across All Activities

The amount of Level A harassment and Level B harassment NMFS may be authorizing incidental to all project activities combined ( i.e., pile driving and drilling to install WTG and ESP monopile and jacket foundations, UXO/MEC detonations, and HRG surveys) are shown in table 33. The annual amount of take which may be authorized reflects the maximum number of take that may occur in each year, based on Avangrid's current schedules, as provided in table 1. Year 1 (2024) take estimates include HRG surveys and UXO/MEC detonations. Year 2 take includes all activities occurring: WTG and ESP foundation installation, HRG surveys, and UXO/MEC detonation. Year 3 includes WTG and ESP foundation installation and HRG surveys. Year 4 take includes WTG and ESP foundation installation (assuming construction schedule B) and HRG surveys. Year 5 take includes HRG surveys only. All activities are expected to be completed by 2030, equating to the 5 years of activities, as described in this preamble. NMFS recognizes that schedules may shift due to a number of planning and logistical constraints such that take may be redistributed throughout the 5 years. However, the total 5-year amount of take for each species, shown in table 33, and the maximum annual take in any one year (table 35) must not be exceeded. Additionally, to reduce impacts to marine mammals, NMFS has required several mitigation and monitoring measures, provided in the Mitigation and Monitoring and Reporting sections, which are activity-specific and are designed to minimize acoustic exposures to marine mammal species.

For common and uncommon, though not “rare,” species where the exposure estimate was less than the mean group size, it was assumed that if one group member was exposed, then the entire group would be exposed. For species where the annual number of predicted exposures was less than the mean group size, the annual take was increased to the mean group size rounded up to the nearest integer. The only species this applied to are the sei whale, Atlantic spotted dolphin, Risso's dolphin, and sperm whale. Because pile driving would occur over either 2 or 3 years, the mean group size rule was carried over from each of the annual take estimates to the total take estimates for the entire construction schedule to account for the possibility that a single exposure could occur in every year of a given construction schedule.

For species that are considered rare but still have the slight potential for occurrence in the Project area, Avangrid requested an amount of annual take assuming one group size of that species may be harassed in any given year. However, due to how rare these species are in the project area, it is not assumed that they would be encountered every year, instead, a group is anticipated to occur only every other year; hence the total amount of take of the 5 years is less than the sum of the annual take across all 5 years. As described above, takes for these species are based on PSO sighting group sizes or on group size from OBIS data. NMFS concurs with this assessment and may authorize takes by Level A harassment and/or Level B harassment for these rare species (table 33).

The amount of take that Avangrid requested, and NMFS may authorize is considered conservative. NMFS does not typically authorize take of rare species in these circumstances; however, given the amount of foundation installation activities that Avangrid is proposing to undertake ( i.e., installation of up to 129 WTG and 2-5 ESP positions), the large harassment zone sizes estimated from foundation installation, the duration of the foundation installation (up to 3 years), that marine mammal distribution is changing and that foundation installation is not scheduled to begin until 2026, NMFS is proposing to allow take for rare species. The one exception is the request for take of beluga whales. There is no beluga whale stock in the U.S. Atlantic and the potential for a beluga whale to occur is incredibly unlikely. Hence, NMFS may not authorize take of beluga whales.

For the species for which modeling was conducted, the allowable take is considered conservative for a number of reasons. The amount of take that may be authorized assumes the most impactful scenario with respect to project design and schedules. As described in the Description of Specific Activities section, Avangrid plans to use monopile and jacket foundations (inclusive of bottom-frame foundations) for all permanent structures ( i.e., WTGs and ESPs). The take that NMFS may authorize for pile driving assumed a maximum piling schedule of two monopiles and four pin piles installed per 24-hour period. The take numbers NMFS may authorize for pile driving are conservatively based on the maximum densities across the construction months. The take numbers that NMFS may authorize for Level A harassment do not fully account for the likelihood that marine mammals would avoid a stimulus when possible before the individual accumulates enough acoustic energy to potentially cause auditory injury, nor do these numbers account for the effectiveness of the required mitigation measures.

If authorized, takes by Level A harassment and Level B harassment for the combined activities of pile driving and drilling during the installation of monopiles and pin piles (assuming 10 dB of sound attenuation), UXO/MEC detonation, and HRG surveys are provided in tables 33 and 34. NMFS also presents the percentage of each marine mammal stock estimated to be taken based on the total amount of annual take in table 35. To inform the negligible impact analysis, NMFS assesses the greatest amount of take of marine mammals allowable in any given year (which in the case of this rule is based on the predicted Year 1 for all species), as well as the total allowable take across all 5 years of the rule. Table 35 also depicts the amount of take relative to each stock assuming that each individual is taken only once, which specifically informs the small numbers determination. Table 34 provides the total take that may be authorized from the entire 5-year effective period of the rule and, if issued, associated LOA.

As a result of the updated modeling for impact pile driving, vibratory pile driving, and drilling, takes by Level A harassment and Level B harassment decreased for many species (values in bold in table 33, 34, and 35). Rare species, having not been included in the modeling for the proposed or final rule, as they are based on OBIS or PSO sighting data, are unchanged since the proposed rule with the exception of the Northern bottlenose whale. Northern bottlenose whale takes by Level B harassment decreased from 12 to 8 as a result of a correction submitted in the January 2024 Application Update by Avangrid (as previously described in the Changes in Information Provided in the Preamble).

In making the negligible impact determination and the necessary small numbers finding, NMFS assesses the maximum total number of takes (Level A harassment and Level B harassment) of marine mammals species or stocks allowable within any one year, and in the negligible impact determination we also assess the impacts of the total take allowable over the 5-year period. In this calculation, the maximum estimated number of Level A harassment takes in any one year is summed with the maximum estimated number of Level B harassment takes in any one year for each species to yield the highest number of estimated take that could occur in any year (table 35). We recognize that certain activities could shift within the 5-year effective period of the rule and the rule allows for that flexibility, however, the takes are not allowed to exceed the maximum annual take shown in table 35 in any year. Of note, the maximum amount of take by Level A harassment is higher for some species in year 1 due to UXO/MEC detonations, though year 3 has the maximum amount of take when takes by Level A harassment is combined with those from Level B harassment. As schedules may shift, and to not underestimate the amount of takes by harassment, the takes under UXO/MEC detonation have been moved to Year 3 (table 34). Year 3 is the year with the maximum amount of take for foundation installation and maximum amount of take when Level A harassment and Level B harassment are combined (table 34).