Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Coastal Virginia Offshore Wind Commercial Project Offshore of Virginia

Federal RegisterMay 4, 2023

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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 217

[Docket No. 230424-0110]

RIN 0648-BL74

Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Coastal Virginia Offshore Wind Commercial Project Offshore of Virginia

AGENCY:

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

ACTION:

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

SUMMARY:

NMFS has received a request from the Virginia Electric and Power Company, doing business as Dominion Energy Virginia (Dominion Energy), for Incidental Take Regulations (ITR) and an associated Letter of Authorization (LOA) pursuant to the Marine Mammal Protection Act (MMPA). The requested regulations would govern the authorization of take, by Level A harassment and Level B harassment, of small numbers of marine mammals over the course of 5 years (2024-2029) incidental to construction of the Coastal Virginia Offshore Wind Commercial (CVOW-C) project offshore of Virginia within the Bureau of Ocean Energy Management (BOEM) Commercial Lease of Submerged Lands for Renewable Energy Development on the Outer Continental Shelf (OCS) Lease Area OCS-A 0483 (Lease Area) and associated Export Cable Routes. Project activities likely to result in incidental take include pile driving activities (impact and vibratory) and site assessment surveys using high-resolution geophysical (HRG) equipment. NMFS requests comments on its proposed rule. NMFS will consider public comments prior to making any final decision on the promulgation of the requested ITR and issuance of the LOA; agency responses to public comments will be summarized in the final notice of our decision. The proposed regulations, if promulgated, would be effective February 5, 2024, through February 4, 2029.

DATES:

Comments and information must be received no later than June 5, 2023.

ADDRESSES:

Submit all electronic public comments via the Federal e-Rulemaking Portal. Go to

www.regulations.gov

and enter NOAA-NMFS-2023-0030 in the Search box. Click on the “Comment” icon, complete the required fields, and enter or attach your comments.

Instructions:

Comments sent by any other method, to any other address or individual, or received after the end of the comment period, may not be considered by NMFS. All comments received are a part of the public record and will generally be posted for public viewing on

www.regulations.gov

without change. All personal identifying information (

e.g.,

name, address), confidential business information, or otherwise sensitive information submitted voluntarily by the sender will be publicly accessible. NMFS will accept anonymous comments (enter “N/A” in the required fields if you wish to remain anonymous).

FOR FURTHER INFORMATION CONTACT:

Kelsey Potlock, Office of Protected Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION:

Availability

A copy of Dominion Energy's Incidental Take Authorization (ITA) application and supporting documents, as well as a list of the references cited in this document, may be obtained online at:

https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable

. In case of problems accessing these documents, please call the contact listed above (see

FOR FURTHER INFORMATION CONTACT

Purpose and Need for Regulatory Action

This proposed rule, if promulgated, would provide a framework under the authority of the MMPA (16 U.S.C. 1361

et seq.

) to allow for the authorization of take of marine mammals incidental to construction of the CVOW-C project within the Lease Area and along export cable corridors to landfall locations in Virginia. NMFS received a request from Dominion Energy for 5-year regulations and a LOA that would authorize take of individuals of 21 species of marine mammals (seven species by Level A harassment and Level B harassment and 21 species by Level B harassment only), comprising 22 stocks, incidental to Dominion Energy's construction activities. No mortality or serious injury is anticipated or proposed for authorization. Please see below for definitions of harassment. Please see the

Legal Authority for the Proposed Action

section below for definitions of harassment, serious injury, and incidental take.

Legal Authority for the Proposed Action

The MMPA prohibits the “take” of marine mammals, with certain exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361

et seq.

) direct the Secretary of Commerce (as delegated to NMFS) to allow, upon request, the incidental, but not intentional, taking of small numbers of marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) within a specified geographical region if certain findings are made, regulations are promulgated (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). Further, NMFS must prescribe the permissible methods of taking and other “means of effecting the least practicable adverse impact” on the affected species or stocks and their habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance, the availability of the species or stocks for taking for certain subsistence uses (referred to as “mitigation”), and requirements pertaining to the mitigation, monitoring and reporting of the takings are set forth.

As noted above, no serious injury or mortality is anticipated or proposed for authorization in this proposed rule. Relevant definitions of MMPA statutory and regulatory terms are included below:

•

Take

—to harass, hunt, capture, or kill, or attempt to harass, hunt, capture, or kill any marine mammal (16 U.S.C. 1362, 50 CFR 216.3);

•

Incidental taking

—an accidental taking. This does not mean that the taking is unexpected, but rather it includes those takings that are infrequent, unavoidable or accidental (see 50 CFR 216.103);

•

Serious Injury

—any injury that will likely result in mortality (50 CFR 216.3);

•

Level A harassment

—any act of pursuit, torment, or annoyance which has the potential to injure a marine mammal or marine mammal stock in the wild (16 U.S.C. 1362); 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 5-year regulations and associated LOA. This proposed rule also establishes required mitigation, monitoring, and reporting requirements for Dominion Energy's proposed activities.

Summary of Major Provisions Within the Proposed Rule

The major provisions of this proposed rule include:

• Authorize take of marine mammals by Level A harassment and/or Level B harassment. No mortality or serious injury of any marine mammal is proposed to be authorized;

• Establish a seasonal moratorium on pile driving during the months of highest North Atlantic right whale (

Eubalaena glacialis

) presence in the project area (November 1st-April 30th);

• Require both visual and passive acoustic monitoring by trained, NOAA Fisheries-approved Protected Species Observers (PSOs) and Passive Acoustic Monitoring (PAM) operators before, during, and after the in-water construction activities;

• Require training for all Dominion Energy personnel that would clearly articulate all relevant responsibilities, communication procedures, marine mammal monitoring and mitigation protocols, reporting protocols, safety, operational procedures, and requirements of the ITA and ensure that all requirements are clearly understood by all participating parties;

• Require the use of sound attenuation device(s) during all vibratory and impact pile driving of wind turbine generators (WTG) and offshore substations (OSS) foundation piles to reduce noise levels;

• Delay the start of pile driving if a North Atlantic right whale is observed at any distance by the PSO on the pile driving or dedicated PSO vessel;

• Delay the start of pile driving if other marine mammals are observed entering or within their respective clearance zones;

• Shut down pile driving (if feasible) if a North Atlantic right whale is observed or if other marine mammals enter their respective shut down zones;

• Conduct sound field verification monitoring during a minimum of three WTGs and all three OSS foundation installation events to measure

in situ

noise levels for comparison against the model results;

• Implement soft starts during impact pile driving and using the least hammer energy possible;

• Implement ramp-up for high-resolution geophysical (HRG) site characterization survey equipment prior to operating at full power;

• Implement various vessel strike avoidance measures;

• Increase awareness of North Atlantic right whale presence through monitoring of the appropriate networks and VHF Channel 16, as well as reporting any sightings to the sighting network;

• Implement Best Management Practices (BMPs) during fisheries monitoring research surveys and activities to reduce the risk of marine mammals being considered at-risk or of interacting with deployed gear; and

• Require frequent scheduled and situational reporting including, but not limited to, information regarding activities occurring, marine mammal observations and acoustic detections, and sound field verification monitoring results.

National Environmental Policy Act (NEPA)

To comply with the National Environmental Policy Act of 1969 (NEPA; 42 U.S.C. 4321

et seq.

) and NOAA Administrative Order (NAO) 216-6A, NMFS must evaluate the proposed action (

i.e.,

promulgation of regulations and subsequent issuance of a 5-year LOA) and alternatives with respect to potential impacts on the human environment.

Accordingly, NMFS proposes to adopt the BOEM Environmental Impact Statement (EIS), provided our independent evaluation of the document finds that it includes adequate information analyzing the effects of promulgating the proposed regulations and LOA issuance on the human environment. NMFS is a cooperating agency on BOEM's EIS. BOEM's CVOW-C Draft Environmental Impact Statement for Commercial Wind Lease OCS-A 0483 (DEIS), was made available for public comment through a Notice of Availability on December 16, 2022 (87 FR 77135), available at

https://www.boem.gov/renewable-energy/state-activities/CVOW-C

. The DEIS had a 60-day public comment period; the comment period was open from December 16, 2022 to February 14, 2023. Additionally, BOEM held three virtual public hearings on January 25, 2023, January 31, 2023, and February 2, 2023.

Information contained within Dominion Energy's ITA application and this proposed rule collectively provide the environmental information related to these proposed regulations and associated 5-year LOA for public review and comment. NMFS will review all comments submitted in response to this proposed rule prior to concluding our NEPA process or making a final decision on the requested 5-year ITR and associated LOA.

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

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

Dominion Energy's proposed project is listed on the Permitting Dashboard. Milestones and schedules related to the environmental review and permitting for the CVOW-C project can be found at

https://www.permits.performance.gov/permitting-project/coastal-virginia-offshore-wind-commercial-project

Summary of Request

On February 16, 2022, NMFS received a request from Dominion Energy for the promulgation of a 5-year ITR and issuance of an associated LOA to take marine mammals incidental to construction activities associated with the CVOW-C project offshore of Virginia in the Lease Area and associated export cable routes. Dominion Energy's request is for the incidental, but not intentional, take of a small number of 21 marine mammal species (comprising 22 total stocks) by Level B harassment and by Level A harassment for seven marine mammal species, comprising 7 stocks. Neither Dominion Energy nor NMFS expects serious injury or mortality to result from the specified activities, and Dominion Energy did not request and NMFS is not proposing to authorize mortality or serious injury of any marine mammals species or stock.

In response to our comments and following extensive information exchanges with NMFS, Dominion Energy submitted a final, revised application on August 5, 2022, that NMFS deemed adequate and complete on August 12, 2022. The final version of the application is available on NMFS' website at

https://www.fisheries.noaa.gov/action/incidental-take-authorization-dominion-

energy-virginia-construction-coastal-virginia

On September 15, 2022, NMFS published a notice of receipt (NOR) of the adequate and complete application in the

Federal Register

(87 FR 56634), requesting comments and soliciting information related to Dominion Energy's request during a 30-day public comment period. During the NOR public comment period, NMFS received one public comment letter from another Federal agency (the United States Geological Survey (USGS)) and one public comment letter from an environmental non-government organization (the Southern Environmental Law Center). NMFS has reviewed all submitted material and has taken these into consideration during the drafting of this proposed rule.

In June 2022, Duke University's Marine Spatial Ecology Laboratory released updated habitat-based marine mammal density models (Roberts

et al.,

2016; Robert and Halpin, 2022). Because Dominion Energy applied marine mammal densities to their analysis in their application, Dominion Energy submitted a final Updated Density and Take Estimation Memo (herein referred to as Updated Density and Take Estimation Memo) on January 10, 2023 that included marine mammal densities and take estimates based on these new models which NMFS posted on our website in May 2023.

In January 2023, BOEM informed NMFS that the proposed activity had changed from what is presented in the adequate and complete MMPA application. Specifically, the changed proposed activity involved the reduction of maximum WTGs built (from 205 to 202 WTGs) as under the original Project Design Envelope (PDE) and the OSSs would be located in the vessel transit routes. Under the 202 build-out, three WTGs would be removed and the three OSSs would be shifted into these WTG positions. However, in late-January 2023, Dominion Energy confirmed that their Preferred Layout of 176 WTGs is the base case for construction, but that they could possibly need up to 7 WTGs re-piled in alternate positions due to unstable sediment conditions, which could necessitate up to 183 independent piling events. WTG positions have been removed from consideration for one or more of the following reasons: impracticable due to foundation technical design risk, shallow gas presence, commercial shipping and navigation risk concerns, erosion risk, and presence of a designated fish haven. Based on the information provided, NMFS carried forward the analysis assuming a total build-out of 176 WTGs plus seven re-piled WTGs (a total of 183 independent piling events for WTGs) and the 3 originally planned OSSs. Due to the significant reduction of turbines from the original proposed action found in the adequate and complete ITA application (reduction of approximately 14 percent), Dominion Energy, in consultation with NMFS, provided an updated proposed action summary, revised exposure estimates, revised take requests, and an updated piling schedule in mid-February 2023 (herein referred to as the Revised Proposed Action Memo). NMFS posted this to our website in May 2023.

NMFS has previously issued six Incidental Harassment Authorizations (IHAs) to Dominion Energy. Two of those IHAs, issued in 2018 (83 FR 39062; August 8, 2018) and 2020 (85 FR 30930, May 21, 2020) supported the development of the Coastal Virginia Offshore Wind project, known as the CVOW Pilot Project (wherein two turbines were constructed). The remaining four IHAs (two of which were modified IHAs) were high resolution site characterization surveys within and around the CVOW-C Lease Area (see 85 FR 55415, September 8, 2020; 85 FR 81879, December 17, 2020 (modified 2020 IHA); 86 FR 21298, April 22, 2021 (modified 2021 IHA); and 87 FR 33730, June 3, 2022).

To date, Dominion Energy has complied with all the requirements (

e.g.,

mitigation, monitoring, and reporting) of the previous IHAs. Information regarding Dominion Energy's take estimates and monitoring results may be found in the Estimated Take section. The monitoring reports can be found on NMFS' website, along with the relevant, previously issued IHAs:

https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable.

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

Description of the Specified Activities

Overview

Dominion Energy's CVOW-C project would allow the Commonwealth of Virginia to meet its clean energy goal of achieving 100 percent clean energy by 2045 through the implementation of up to 5,200 megawatts (MW) of offshore wind-generated energy, as established in the Virginia Clean Economy Act (HB 1526/SB 851;

https://lis.virginia.gov/cgi-bin/legp604.exe?201+ful+CHAP1193+hil&201+ful+CHAP1193+hil

). To achieve this, Dominion Energy has proposed to construct and operate CVOW-C in state and Federal waters of the Atlantic Ocean in the Lease Area that is capable of producing between 2,500 and 3,000 MW of renewable energy and would be the largest offshore wind project in the United States at the time of its construction.

Dominion Energy's precursor pilot project (

i.e.,

CVOW Pilot Project) was a 12 MW, two-turbine test project and the first to be installed in Federal waters. Designed as a research/test project, the two turbines associated with the CVOW Pilot Project became operational in October 2020 approximately 27 miles (mi; 43.45 kilometers (km)) off of Virginia Beach, Virginia. Information on this Pilot Project was used to inform the proposed CVOW-C project. More information on the Pilot Project can be found on BOEM's website (

https://www.boem.gov/renewable-energy/state-activities/coastal-virginia-offshore-wind-project-cvow

) and in the IHA authorized by NMFS in May 2020 for BOEM Lease Area OCS-A-0497 (

https://www.fisheries.noaa.gov/action/incidental-take-authorization-dominion-energy-virginia-offshore-wind-construction-activities

CVOW-C would consist of several different types of permanent offshore infrastructure, including up to 176 wind turbine generators (WTGs;

e.g.,

such as the Siemens Gamesa SG-14-222 DD 14-MW model with power boost technology potentially allowing up to 14.7-MW, equating to a total of 2,587.2-MW for full build-out), three offshore substations (OSS), and inter-array and substation interconnect cables. Dominion Energy plans to install WTG and OSS foundations via a joint-installation approach using both vibratory and impact pile driving. Dominion Energy would also conduct the following supporting activities: temporarily install and remove, by vibratory pile driving, up to nine cofferdams to connect the offshore export cables to onshore facilities; temporarily install and remove, by impact pile driving and a pipe thruster, respectively, up to 108 goal posts (12 goal posts for each of nine Direct Pipe locations) to guide casing pipes; permanently install scour protection around WTG and OSS foundations; permanently install and perform trenching, laying, and burial activities associated with the export cables from the OSSs to shore-based switching and sub-stations and WTG inter-array cables; annually perform, using active acoustic sources with frequencies of less than 180 kilohertz (kHz), high-resolution vessel-based site characterization geophysical (HRG) surveys; and intermittently perform, via a modified dredge, and a pot-based monitoring approach, fishery monitoring surveys to enhance existing data for specific benthic and pelagic species of concern. Vessels would transit within the project area and between ports and the wind farm to transport crew, supplies, and materials to support construction activities. All offshore cables would be connected to onshore export cables at the sea-to-shore transition point via trenchless installation (

i.e.,

underground tunneling utilizing micro tunnel boring installation methodologies) in a parking lot found west of the firing range at the State Military Reservation located in Virginia Beach, Virginia. From the sea-to-shore transition point, onshore underground export cables are then connected in series to switching stations/substations, overhead transmission lines, and ultimately to the grid connection.

Marine mammals exposed to elevated noise levels during impact and vibratory pile driving and site characterization surveys may be taken, by Level A harassment and/or Level B harassment, depending on the specified activity.

Dates and Duration

Dominion Energy anticipates that activities with the potential to result in incidental take of marine mammals would occur throughout all five years of the proposed regulations which, if issued, would be effective from February 5, 2024, through February 4, 2029. Based on Dominion Energy's proposed schedule, the installation of all permanent structures would be completed by the end of October 2025. More specifically, the installation of WTG foundations is expected to occur between May 1st-October 31st of 2024 and 2025, over approximately 12 months (6 months within each year). OSS jacket foundations using pin piles would be installed between May 1st-October 31st, 2024 and 2025. However, delays due to weather or other unanticipated and unforeseen events may require Dominion Energy to install some foundations in 2026. If this occurs, foundation installation would occur between the predetermined pile driving seasonal window (May 1st-October 31st in 2026) and occur over 6 months. However, as this would represent a shift in the schedule, rather than additional piles being installed, the proposed activities would still maintain the same amount of take proposed for authorization, both annual maximum and five-year total. The temporary structures used for nearshore cable landfall construction (

i.e.,

temporary cofferdams and temporary goal posts) would be installed and subsequently removed between May 1st-October 31st, 2024. Lastly, Dominion Energy anticipates HRG survey activities using boomers, sparker, and Compressed High-Intensity Radiated Pulses (CHIRPs) to occur annually and across the five-year period. Up to 65 days of surveys are planned in 2024, 249 are planned in 2025, 58 are planned in 2026, and 368 survey days are planned annually in each of 2027 and 2028. No surveys are planned to occur in 2029. These surveys may occur across the entire CVOW-C Lease Area and Export Cable Routes and may take place at any time of year.

Dominion Energy has provided a schedule for all of their proposed construction activities (Table 1). Based on the schedule presented, no activities (installation, removal, or HRG surveys) are planned to occur in 2029, even though part of this year would fall within the five-year effective period of the proposed regulations. This table also presents a breakdown of the timing and durations of the activities proposed to occur during the construction and operation of the CVOW-C project.

Table 1—CVOW-C's Construction and Operations Schedule During the Effective Period of the LOA

Project activity

Expected timing

Expected duration

(approximate)

Scour Protection Pre-Installation

Q2 through Q4 of 2024

Q2 through Q4 of 2025

9 months.

WTG Foundation Installation

Q2 through Q4 of 2024

Q2 through Q4 of 2025

6 months.

Scour Protection Post-installation

Q2 through Q4 of 2024

Q2 through Q4 of 2025

9 months.

OSS Foundation Installation

Q2 through Q4 of 2024

Q2 through Q4 of 2025

6 months.

Cable Landfall Construction (Goal Posts and Cofferdams)

Q1 through Q4 of 2024

6 months.

HRG Surveys

Q1 2024 through Q4 2028

Any time of year.

Site Preparation

Q1 2024 through Q2 2024

6 months.

Inter-array Cable Installation

Q2 2025 through Q4 2026

19 months.

Export Cable Installation

Q3 2024 through Q3 2025

14 months.

Fishery Monitoring Surveys:

Surf Clam

Whelk

Black Sea Bass

Q2 2023

Q2 2023 through Q1 2025

1 week.

24 months.

Note:

“Q1, Q2, Q3, and Q4” each refer to a quarter of the year, starting in January and comprising 3 months each. Therefore, Q1 represents January through March, Q2 represents April through June, Q3 represents July through September, and Q4 represents October through December.

While the effective period of the proposed regulations would extend a few months into 2029, no activities are proposed to occur in 2029 by Dominion Energy so these were not included in this table.

Activities would only occur between May 1st through October 31st annually.

Activities would begin in February 2024, upon the issuance of a LOA, and continue through construction and post-construction.

For HRG surveys, Dominion Energy anticipates up to 65 days of surveys would occur during the pre-construction period (2024), up to 307 days during the primary construction years (2025 and 2026), and up to 736 days would be needed during the post-construction years (2027 and 2028) with a 50/50 split of 368 days each year. No surveys are planned for 2029.

Dominion Energy anticipates that all WTGs and OSS foundations will be installed by October 31st, 2025; however, unanticipated delays may require some foundation pile driving to occur in 2026.

Some fishery monitoring survey activities are planned prior to February 2024 but are not included here as they would not occur during the effective dates of the ITR and LOA.

Dates displayed here are for field work, as that would be the only component that could impact marine mammals.

Although cable landfall activities are anticipated to occur over 9-12 months total, activities capable of harassing marine mammals would only occur for the specified duration described here as other activities necessary for landfall construction (

i.e.,

area preparation, material transportation, etc.) would also occur.

Dominion Energy anticipates that the first 40 WTGs would become operational in 2025, after foundation installation is completed and after all necessary components (such as array cables, OSSs, export cables routes, and onshore substations) are installed. Up to 120 additional WTGs would be commissioned/operational in 2026. Dominion Energy anticipates that all turbines would be commissioned by 2027, with the last 16 being operational that year.

Specific Geographic Region

Dominion Energy would construct the CVOW-C project in Federal and state waters offshore of Virginia within the BOEM Lease Area OCS-A 0483 and associated Export Cable Routes (Figure 1). The Lease Area covers approximately 456.5 km

(112,799 acres) and is located approximately 27 mi (43.5 km) east of Virginia Beach, Virginia. The water depths in the Lease Area range from 19.9 m to 38.1 m (65 to 125 ft) while water depths along the Export Cable Routes range from 0 to 28 m (0 to 92 ft). Cable landfall construction work would be conducted in shallow water (temporary cofferdams would be in water 3.3 m (10.83 ft) deep, and the goal posts would be at depths of 22.9 m (75 ft)). Sea surface temperatures range from 32 to 88 degrees Fahrenheit (°F; 0 to 31 degrees Celsius (°C)) while the depth-averaged annual water temperature is 56.39 °F (13.55 °C) (NOAA n.d.B). Cables would come ashore adjacent to the western boundary of the State Military Reservation firing range in Virginia Beach.

Dominion Energy's specified activities would occur along a portion of the Mid-North Atlantic continental shelf that experiences various concurrent processes that shape the overall geology of the region. These processes include glacio-eustatic sea level change (

i.e.,

a change in sea level due to the uptake or release of water from glaciers and polar ice), drainage from Chesapeake Bay, and storm-related effects to sedimentation. The basin structure in which the CVOW-C project area is located, the Baltimore Canyon Trough, is oriented northeast to southwest and consists of a wedge of sediments that thicken to the east (Dominion Energy, 2023).

The Mid-Atlantic Bight, where the CVOW-C project would be located, spans from Cape Hatteras, North Carolina to Cape Cod, Massachusetts and continues to extend into the west Atlantic to the 100-m isobath. The oceanographic conditions along the Mid-Atlantic Bight are comparable to the conditions found along the Mid-Atlantic East Coast, where summer months are warmer and winter months are milder. The area is known for its high levels of primary productivity, specifically in the nearshore and estuarine regions, where coastal phytoplankton tend to bloom in the winter and summer. Given the proximity to the continental shelf, this area forms an important habitat for various benthic and fish species, as well as forms important habitat for fin whales, humpback whales, North Atlantic right whales, and other large whales as they migrate through the area. The CVOW-C project area is located within the Mid-Atlantic Bight and relatively flat with “very gentle to gentle slopes”, as described by the BOEM classification found in the CVOW-C Construction and Operations Plan (COP) (Dominion Energy, 2023). In the Export Cable Routes, the seafloor slopes are less than 1 degree (“very gentle” based again on the BOEM classification; Dominion Energy, 2023). The most significant slopes can be found on the flanks of morphological features and other topographic highs where the seabed gradient ranges up to 4 degrees (Dominion Energy, 2023). The most prominent seabed features with the project area are pronounced sand ridges that create a ridge and swale topography. In the northeastern portion of the project area, the heights of the sand ridges are lower, topographic variation across the ridges is reduced, seafloor bathymetry is deeper, and water depths are less variable.

A complete mapping of the seabed has identified a low number of boulders present on the seafloor (Dominion Energy, 2023). Only 10 boulders and 110 seabed targets interpreted as possible boulders have sizes greater than 1 m (3 ft). No patterns were identified in the location of boulders across the Lease Area and Export Cable Routes.

The seafloor in the CVOW-C project area is dynamic and changes over time due to current, tidal flows, and wave conditions. The benthic habitat of the project area contains a variety of seafloor substrates, physical features, and associated benthic organisms. The soft bottom sediments in the project area are reflective of the rest of the Mid-Atlantic Bight region, and characterized

by fine sand as well as gravel and silt/sand mixes (Milliman, 1972; Steimle and Zetlin, 2000). Underwater soils in the area are known to be soft, with two specific soils noted that could increase the risk of pile run (Dominion Energy, 2023). The presence of bedforms, mobile sediments, and potential for scouring exist in the project area (Dominion Energy, 2023). However, the paleochannel strata is not considered a weak layer due to stiffness and strength values being within normal ranges and as such, is not considered a hazard to cable or foundation installation (Dominion Energy, 2023). The dominant benthic fauna within the Lease Area are annelids, mollusks, and arthropods (Dominion Energy, 2023).

Additional information on the underwater environment's physical resources can be found in CVOW-C's COP (Dominion Energy, 2023) available at

https://www.boem.gov/renewable-energy/state-activities/coastal-virginia-offshore-wind-project-construction-and

BILLING CODE 3510-22-P

EP04MY23.081

BILLING CODE 3510-22-C

Figure 1—The CVOW-C Project Area

Detailed Description of Specified Activities

Below, we provide detailed descriptions of Dominion Energy's activities, explicitly noting those that are anticipated to result in the take of marine mammals and for which incidental take authorization is requested. Additionally, a brief explanation is provided for those activities that are not expected to result in the take of marine mammals.

WTG and OSS Foundations

Dominion Energy proposes to install up to 176 WTGs on monopile foundations and 3 OSSs on jacket foundations. They anticipate all WTG foundations could be installed between May 1st through October 31st in 2024 and 2025, over the course of six months in each year. However, it may be possible that monopile installation associated with the WTG foundations would need to continue into a third year (2026), depending on construction logistics and local and environmental conditions that may influence Dominion Energy's ability to maintain the planned construction schedule. If this is determined to be necessary, WTG foundations would only be installed between May 1st through September 30th of 2026. However, this schedule shift would not change NMFS' proposed determinations as the total number of piles would remain the same. While this shift is unlikely to occur, the proposed rulemaking does retain flexibility in addressing unforeseen circumstances. However, all foundations would be installed during the effective period of this proposed rule, if issued. OSS jacket foundations would most likely be installed in August 2024; however, they could be installed anytime between May 1st through October 31st. For both types of foundations, Dominion Energy has committed to not installing from November 1st through April 30th, annually.

A WTG monopile foundation typically consists of a single steel tubular section, with several sections of rolled steel plate welded together. Each monopile would have a maximum diameter tapering from 7.5 m (24.6 ft) at the top to 9.5 m (31 ft) at the seafloor (collectively referred to as a 9.5/7.5-m monopile). WTGs would be spaced approximately 0.75 nautical miles (nm; 1.39 km) in an east-west direction and 0.93 nm (1.72 km) in a north-south direction and will have an average penetration depth of 42 m (138 ft; between 30 m and 46 m per Attachment Z-3 of Appendix A in Dominion Energy's ITA application). Although only 176 WTGs would be installed, seven foundations may need to be re-installed at a different location; hence Dominion Energy has accounted for up to 183 WTG individual piling events in its analysis, which we have carried forward with in this proposed rule.

Each OSS installed by Dominion Energy would be supported by a jacket foundation. A piled jacket foundation is formed by a steel lattice construction (comprising tubular steel members and welded joints) secured to the seabed by means of hollow steel pin piles attached to the jacket. Each jacket foundation would consist of up to four pin piles. In total, Dominion Energy would install up to 3 OSSs for a total of 12 pin piles. Up to two pin piles would be installed per day. Pin piles will have a maximum diameter of 2.8 m (9.2 ft) each and will be installed vertically. The maximum penetration depth of each pin pile would be 82 m (269 ft).

Given the project area's soil conditions, the installation of both WTG monopile foundations and OSS jacket foundations would necessitate the use of both vibratory and impact pile driving to avoid pile run (also known as “punch-through”). Pile run can occur when a monopile or a pin pile rapidly penetrates in an uncontrolled manner through a weak layer of soil, due to the soil resistance being lower than the weight of the pile and hammer (transferring impulsive energy to the pile). Pile runs can occur instantaneously and through a depth of meters to dozens of meters. A pile run incident can have severe negative consequences, both for the safety of personnel aboard the installation vessel and significant risk of damage to equipment. To mitigate this risk, Dominion Energy would first perform vibratory hammering, which would allow for a more controllable installation process when installing piles in soft sediments as the vibrohammer is directly in contact with the pile (see Figures 2 through 5 in Dominion Energy's ITA application), as opposed to installation using the impact hammer (see Figures 6 and 7 in Dominion Energy's ITA application). Once the pile run risk depth has been passed, the method of installation would transition from a vibratory hammer to an impact hammer. It is anticipated the transition from a vibratory hammer to an impact hammer would require approximately 1.2 hours wherein no pile driving would occur. Once installation of the monopile and/or pin pile is complete, the pile driving vessel would move to the next installation location. While Dominion Energy states that not all piles will require the use of the vibrohammer in conjunction with the impact hammer, it was considered more conservative to analyze all installed piles using this dual approach as it is not yet known how many would require the dual installation method. No concurrent pile driving at multiple locations would occur.

Per monopile, use of the vibrohammer is estimated to occur for approximately 30 to 60 minutes (depending on if the pile uses a standard driving or hard-to-drive scenario, respectively) to firmly stabilize the foundation pile. A 72 minute (1.2 hour) pause to allow for the vibratory hammer to be exchanged with an impact hammer would occur. Then, the impact hammer would be used for approximately three hours (constituting approximately 3 hours for 3,240-3,720 total hammer strikes, with more strikes needed if the pile is considered difficult to install). A joint standard and hard-to-drive scenario (Scenario 3) for the installation of up to two monopiles in a single day may require up to 90 minutes of vibratory pile driving followed by up to 6,960 hammer strikes. In all situations, the impact hammer would drive the pile until it reaches its target embedment depth (approximately 42 m (138 ft) for monopiles). The three possible WTG monopile installation scenarios are laid out in Table 2 below:

Table 2—WTG Monopile Scenarios With Scenario-Specific Installation Characteristics

Installation scenario

Number of

WTG monopiles

installed

Maximum

vibratory hammer

duration

(minutes)

Maximum

impact hammer

strikes

Impact hammer

energy

(kJ)

Scenario 1 (Standard)

3,240

4,000

Scenario 2 (Hard-to-drive)

3,720

4,000

Scenario 3 (Standard and Hard-to-drive)

6,960

4,000

For pin piles, vibratory pile driving is anticipated to require approximately 120 minutes (2 hours), a 72 minute (1.2 hours) pause in activities, and then continue with impact pile driving using a hammer energy up to 3,000 kJ, resulting in a total estimate of 15,210 hammer strikes. As with WTG foundations, the impact hammer would drive the pin pile until it reaches its target embedment depth (approximately 82 m (269 ft) for pin piles). A maximum of two pin piles would be driven per day. Each OSS jacket foundation would take approximately five days to install with a total of 30 days needed for the completion of all three OSSs (n=3) with all of their pin piles (n=12). This 30-day period does include periods of non-pile driving time where other activities related to the jacket foundations may be installed.

The current construction schedule assumes foundation installation would occur in 2024 and 2025; however, as previously discussed in the Dates and Duration section, limited installation of WTGs may need to be installed in 2026 if the project falls off of the construction schedule. Given an estimated installation schedule, Dominion Energy expects that up to 95 monopile foundations would be installed in 2024 and up to 88 monopiles would be installed in 2025. If pile driving must occur in this 3rd year, installation would only occur across a five month period (May 1st through September 30th, 2026). All WTG and OSS foundation installation would occur during daylight hours only. The only exception would be if, for safety reasons, ceasing pile driving activities would compromise both the health of humans and the environment or if ceasing the pile driving would cause instability and integrity concerns on the project. In most cases, one pile would be installed per day, although two may be installed during some months. No concurrent pile driving is planned or proposed to occur. The same exception described above for WTG foundations applies to OSS foundations where integrity or safety concerns may necessitate the pile to be finished after sunset. The proposed WTG and OSS pile driving schedule can be found in Table 3 below that describes the construction schedule on both an annual and monthly basis.

Table 3—Proposed Pile Driving Schedule for the CVOW-C Project of 176 WTGs and 3 OSSs, Plus 7 Possible WTG Re-Piling Events

Year

Month

Total proposed number of piles

Number of hard-to-drive piles

Number of standard piles

Days when two

monopiles may

be installed

per day

2024

May

June

July

August

2 monopiles; 12 pin piles

September

October

2024 Annual Total

95 monopiles; 12 pin piles

2025

May

June

July

August

September

October

2025 Annual Total

88 monopiles

Included only if seven re-piling events are necessary.

While Dominion Energy plans for all pile driving to be completed by the end of the 2025 piling period (end of October 2025), unforeseen circumstances may necessitate that piling would need to continue into 2026. While not planned or anticipated, the proposed rule would allow for flexibility in shifting certain activities with the understanding that the maximum estimated takes would not exceed the amount described in the proposed rule.

Cable Landfall Construction

To support the connection of the offshore cable with the onshore cable, Dominion Energy would install both temporary goal posts and temporary cofferdams approximately 1,000 m (3,281 ft) offshore of the State Military Reservation in Virginia Beach, Virginia. These activities are two components of a broader set of activities conducted during cable landfall construction. The goal posts and cofferdams would support work associated with installing casing pipes housing the export cables. Dominion Energy would install the 9 casing pipes approximately 50 ft apart from each other at the cable landfall construction site using a Trenchless Installation approach. Using a tunneling approach similar to horizontal directional drilling (HDD), a boring machine would excavate the ground while simultaneously pushing strings of steel casing pipes along umbilical lines

using rollers or other movable support structures behind the boring drill using a pipe thruster machine. The export cables would be fed through these pushed casing pipes, which would terminate at an onshore exit point located west of the firing range from the State Military Reservation.

Temporary goal posts (made up of 42-in diameter steel pipe piles) would be installed between each exit location and would be used to guide the progress and movement of the casing pipes and to provide lateral stability. Temporary cofferdams are used to aid cable pull in as the cable is fed through the underground tunnel (located 6.6 ft (2 m) below the seabed). A technical description of the Trenchless Installation approach can be found in Section 1 of Dominion Energy's ITA application.

Trenchless installation requires the use of extensive equipment that would be staged at the onshore location for the cable. However, only the equipment required to extract the boring device, post-tunneling, is temporarily staged at the onshore exit location. Despite the extensive equipment necessary for this activity (see the ITA application for details), most of it is not expected to result in the take of marine mammals as the source levels are all generally very low. Even the pipe thruster does not vibrate or make noise and simply pushes the pipe forward with the boring device. Because of this, only the aspects for cable landfall construction that could cause the take of marine mammals (

i.e.,

impact and vibratory pile driving) is discussed further. The aspects of landfall construction that could cause the harassment of marine mammals is specifically due to the installation of steel pipe piles for goal posts and the installation and removal of sheet piles for cofferdams.

The goal posts would consist of 1.07 m (42 in) steel pipe piles that would be installed using an impact hammer for up to 130 minutes daily (a maximum of 2 installed per day). The duration of each strike of the impact hammer would be between 0.5-2 seconds in duration and necessitate approximately 260 strikes per pile. Up to 12 goal posts are required at each of the 9 casing pipe locations; hence 108 goal posts would be installed. Given there are 12 goal posts per each of the nine Direct Pipe locations, a total of 108 piles would be installed. Given up to 2 piles would be installed per day, there could be 520 strikes per day. To install all goal posts, Dominion Energy would conduct pile driving for 54 days.

Once installed, the goal posts can be removed using equipment not expected to generate any underwater acoustic noise as the majority of the force applied would be to overcome the skin friction of the material that is embedded in the substrate. This is expected to consist of pulling/tugging of the piles using mechanical or hydraulic equipment and take a similar amount of time of installation (

i.e.,

a total of 54 days for removal, although no take is expected). Based on Dominion Energy's schedule, which includes both installation and removal of the goal posts, these activities are expected to occur in 2024, between May 1st-October 31st, and necessitate approximately 6 months for complete installation and removal. Given no take is expected from the removal of goal posts, only the 54 days for installation of 108 total pipe piles has been carried forward into the Estimated Take of Marine Mammals section.

Dominion Energy also anticipates that up to nine temporary cofferdams, which would only be installed and removed via vibratory pile driving, may be necessary during cable landfall construction activities. These would be located at the Nearshore Trenchless Installation Punch-Out location, where the export cables would transition (via underground drilling) to the onshore cable landing location, to facilitate the preferred approach of lowering of the Direct Pipe burial underground (approximately 2 m (6.6. ft) below the seabed) to reduce the need for additional cable protections and to minimize the release of sediments and drilling fluids into the water. Each temporary cofferdam would consist of 30 to 40 steel sheet piles measuring 0.51 m (20 in) in diameter arranged in a predetermined configuration (270 to 360 steel sheet piles total for all nine cofferdams). Vibratory pile drivers would be used to both install and remove the steel sheet piles. Each sheet pile would necessitate approximately 2 to 3 minutes of active drive time for installation, at a maximum installation rate of 20 sheet piles per day (up to 40-60 minutes daily). To allow for flexibility in the plan, Dominion Energy has assumed installation will take approximately 3 days (180 minutes total) per cofferdam. Removal of these sheet piles would also occur by a vibratory driver and is estimated to take approximately the same amount of time to remove as it was to install for a total of 3 days per cofferdam. A single cofferdam would take a total of 6 days to install and remove. In total, pile driving (installation and removal) associated with all cofferdams would occur over 54 non-consecutive days.

Collectively, Dominion Energy estimates that the installation and removal of all necessary components for cable landfall activities that have the potential to result in take of marine mammals (

i.e.,

pile driving of goal posts and cofferdams) would take 108 days. However, within this 45 week period, activities not expected to harass marine mammals would also be occurring (

e.g.,

area preparation, material transportation, equipment staging,

etc.

) as the activities necessary for the installation and removal of all relevant goal posts and cofferdams are not consecutive. Therefore, Dominion Energy has estimated that activities potentially resulting in the take of marine mammals would only be occurring for approximately 6 months between May 1st through October 31st, 2024, which is what is described here. Although temporary cofferdam installation and removal is anticipated to occur from May 1st through October 31st of 2024 and take approximately 6 months, per Dominion Energy's construction schedule, both installation and removal will not occur within a consecutive 6 days (the total number of days for installation and removal to occur) but may instead occur at different points during the 6 month estimated duration.

High-Resolution Geophysical Surveys

HRG surveys would be conducted to identify any seabed debris and to support micro-siting of the WTG and OSS foundations and all cable routes. After construction is complete, HRG surveys would be conducted to ensure that all underwater project components have been properly installed. These surveys may utilize acoustic equipment such as multibeam echosounders, side scan sonars, shallow penetration sub-bottom profilers (SBPs) (

e.g.,

Compressed High-Intensity Radiated Pulses (CHIRPs) non-parametric SBP), medium penetration sub-bottom profilers (

e.g.,

sparkers and boomers), and ultra-short baseline positioning equipment, some of which are expected to result in the take of marine mammals. Surveys would occur annually, with durations dependent on the activities occurring in that year (

i.e.,

construction years versus operational years). Of the HRG equipment types proposed for use, the following sources have the potential to result in take of marine mammals:

• Shallow penetration sub-bottom profilers (SBPs) to map the near-surface stratigraphy (top 0 to 5 m (0 to 16 ft) of sediment below seabed). A CHIRP system emits sonar pulses that increase in frequency over time. The pulse length frequency range can be adjusted to meet

project variables. These are typically mounted on the hull of the vessel or from a side pole.

• Medium penetration SBPs (boomers) to map deeper subsurface stratigraphy as needed. A boomer is a broad-band sound source operating in the 3.5 Hz to 10 kHz frequency range. This system is typically mounted on a sled and towed behind the vessel.

• Medium penetration SBPs (sparkers) to map deeper subsurface stratigraphy as needed. A sparker creates acoustic pulses from 50 Hz to 4 kHz omni-directionally from the source that can penetrate several hundred meters into the seafloor. These are typically towed behind the vessel with adjacent hydrophone arrays to receive the return signals.

Table 4 identifies all the representative survey equipment that may be used during the CVOW-C proposed project.

Table 4—Acoustic Sources Planned for Use During the CVOW-C Proposed Project and Their Operational Parameters

Equipment classification

Representative equipment

Operating

frequencies

(kHz)

p,pk

Primary beam width

(degrees)

Pulse duration

(millisecond)

Subsea Positioning/ultra-short baseline (USBL)

Sonardyne Ranger 2 USBL

EvoLogics S2CR

35-55

48-78

188

178

191

186

Horizontally Omnidirectional

500-600

ixBlue Gaps

20-30

191

194

200

9-11

Multibeam Echosounder

R2Sonics 2026

170-450

191

221

0.45 × 0.45-1 × 1

0.015-1.115

Synthetic Aperture Sonar (SAS), combined bathymetry/sidescan

Kraken Aquapix

337

210

213

>135 vertical, 1 horizontal

1-10

Side Scan Sonar

EdgeTech 4200 dual frequency

300 and 600

206

212

140

5-10

Parametric SBP

Innomar SES-2000 Medium 100

2-22

241

247

0.07-1

NonParametric SBP

EdgeTech 216 CHIRP

2-16

193

196

15-25

5-40

EdgeTech 512 CHIRP

0.5-12

177

191

16-41

Medium Penetration Seismic

Geo Marine Dual 400 Sparker 800J

0.25-4

200

210

Omnidirectional

0.5-0.8

Applied Acoustics S-Boom (Triple Plate Boomer 1000J)

0.5-3.5

203

213

Magnetometer (Towed)

Geometrics G882

200

192

190

1.13

Note:

dB re 1 µPa m—decibels referenced to 1 MicroPascal at 1 meter; kHz—kilohertz.

The operating frequencies of these sources are above all relevant marine mammal hearing thresholds (>180 kHz) and are not expected to cause take by harassment of marine mammals.

The source level is based on data from Crocker and Franantonio (2016) using the EdgeTech 4200 at 100 percent power and 100 kHz as a proxy.

The source level is based on data from Crocker and Franantonio (2016) using the EdgeTech 512i at 100 percent power as a proxy.

The source level is based information provided by the source manufacturer in the supplemental attachment to the ITA application called “Noise Level Stacked 400—tuned”.

The source level is based on data from Crocker and Franantonio (2016) using the Applied Acoustic S-Boom with CSP-N Energy Source set at 1,000 joules as a proxy.

The beam width is based on data from Crocker and Franantonio (2016) using the Applied Acoustics S-Boom as a proxy.

As shown in Table 4 above, multibeam echosounders and side scan sonars used by Dominion Energy operate at frequencies above 180 kHz, which is outside of any marine mammal hearing range. Hence, take from these sources is not anticipated. In addition, due to the characteristics of non-impulsive sources (

i.e.,

Ultra-Short BaseLine (USBL), Innomar, and other parametric sub-bottom profilers), take is not anticipated due to operating characteristics like very narrow beam width which limit acoustic propagation. Finally, Dominion Energy may also use magnetometers; however, this equipment does not have an acoustic output, hence no take is anticipated. No harassment can be reasonably expected from the operation of any of these sources; therefore, they are not considered further in this proposed action. The sources that have the potential to result in harassment to marine mammals include CHIRPs, boomers, and sparkers.

HRG surveys would utilize between two or three vessels working concurrently in different sections of the Lease Area and Export Cable Routes. Both vessels would be operating several kilometers apart at any one time. On average, 58 km (36 mi) would be surveyed each survey day, per vessel, at a speed of approximately 2.4 km/hour (1.3 kts) on a 24-hour basis although some vessels may only operate during daylight hours (survey vessels operating for 12-hours). During the five-years the proposed rule would be effective an estimated area of 64,264 km

(24,812.5 mi

; 15,879,980.2 acres) will be surveyed across the CVOW-C project area.

HRG site characterization surveys would occur annually and throughout the five years of the proposed authorization with duration dependent on the activities occurring in that year (

i.e.,

construction versus non-construction year). However, HRG survey activities would not commence earlier than February 5, 2024 (

i.e.,

the effective date of the proposed rule). The HRG survey schedule assumes 24-hour operations and does account for periods of potential downtime due to inclement weather or technical malfunctions. HRG surveys are anticipated to operate at any time of year for a maximum of 1,108 active sound source days (

i.e.,

days in which an acoustic source would be used) over the five-year project. Up to 65 days are anticipated pre-construction, 307 are anticipated to occur during the primary construction years (2025 and 2026), and 736 would occur the post-construction years (368 survey days annually). While the effective period of the proposed rulemaking would continue through a few months in 2029, no activities are planned to occur during this year so none are described here. An approximated schedule for Dominion Energy's HRG survey effort is shown in Table 5. As Dominion Energy is not sure of the exact geographic locations of the survey effort, these values cannot cleanly be broken up between the Lease Area and the Export Cable Routes. However, the values presented in Table 5 provide a comprehensive accounting of the total survey effort anticipated to occur, annually, by Dominion Energy.

Table 5—Proposed HRG Survey Schedule for the CVOW-C Project

Survey segment

Year

Duration

(days)

Pre-Lay Surveys

2024

As-Built Surveys and Pre-Lay Surveys

2025

249

As-Built Surveys

2026

Post-Construction Surveys

2027

368

Post-Construction Surveys

2028

368

As multiple vessels (

i.e.,

two survey vessels) may be operating concurrently across the project area, each day that a survey vessel is operating counts as a single survey day. For example, if two vessels are operating in one of the Export Cable Routes and one is operating in the Lease Area, but both are operating concurrently, this counts as two survey days.

Cable Laying and Installation

Cable burial operations would occur both in the Lease Area and export cable routes from the least area to shore. The inter-array cables would connect the 176 WTGs to any one of the three OSSs. Cables within the Export Cable Routes would carry power from the OSSs to shore at the landfall location near the firing range at the State Military Reservation in Virginia Beach, Virginia. The offshore export and inter-array cables would be buried in the seabed at a target depth of up to 0.8 m (2.6 ft) to 3 m (9.8 ft), although the exact depth will depend on the substrate in the area.

Cable laying, cable installation, and cable burial activities planned to occur during the construction of the CVOW-C project may include the following: jet plowing, jet trenching, chain cutting, hydro-plowing (simultaneous lay and burial), mechanical plowing (simultaneous lay and burial), pre-trenching (both simultaneous and separate lay and burial), mechanical trenching (simultaneous lay and burial), and/or other available technologies. As the noise levels generated from cable laying and installation work are low, the potential for take of marine mammals to result is discountable. Dominion Energy is not requesting and NMFS is not proposing to authorize take associated with cable laying activities. Therefore, cable laying activities are not analyzed further in this document.

Site/Seafloor Preparation

Prior to installation activities, Dominion Energy would conduct debris clearance, pre-lay grapnel runs, Unexploded Ordnance/Munitions and Explosives of Concern (UXO/MEC) relocation, and pre-lay surveys. While Dominion Energy does not expect any sandwave clearance or boulder removal activities to occur, planned vessel use described below in Table 6 indicates that these activities may occur. Because of this, we include additional information on what these activities may entail and how they would affect marine mammals.

Typically for offshore construction projects, some dredging may be required prior to cable laying due to the presence of sandwaves. Sandwave clearance is typically undertaken where cable exposure is predicted over the lifetime of a project due to seabed mobility. This facilitates cable burial below the reference seabed. Alternatively, sandwave clearance may be undertaken where slopes become greater than approximately 10 degrees (17.6 percent), which could cause instability to the burial tool. Dominion Energy does not anticipate any sandwave clearance (Dominion Energy, 2023). However, while unanticipated, if it becomes necessary to remove sandwaves, Dominion Energy will clear the area using subsea excavation methods. The work could be undertaken by traditional dredging methods such as a trailing suction hopper. Controlled flow excavation may be used to induce water currents to force the seabed into suspicion, where it would otherwise be directed to eventually settle (Dominion Energy, 2023). In some cases, pre-sweeping of the sandwaves may be necessary to provide a sufficient excavated platform at the base of the sandwave for tool installation. Surveys using multi-beams and other equipment may be necessary to inform on the seabed conditions before and after sandwave clearance and cable lay activities (Dominion Energy, 2023).

For monopile and jacket foundation installation, seafloor preparation could include required boulder clearance and removal of any obstructions within the Seafloor Preparation Area at each foundation location. Scour protection installation will occur prior to and/or after installation and will involve a rock dumping vessel placing scour at each foundation location.

For export cable installation, seafloor preparation typically includes required sandwave leveling, boulder clearance, and removal of any out of service cables. Boulder clearance trials are normally performed prior to wide-scale seafloor preparation activities to evaluate efficacy of boulder clearing techniques. Additionally, pre-lay grapnel runs may be undertaken to remove any seafloor debris along the Export Cable Routes. A specialized vessel will tow a grapnel rig along the centerline of each cable to recover any debris to the deck for appropriate licensed disposal ashore, where practicable. Concrete mattress separation layers may also be installed at cable routes prior to cable installation for both in-service assets as well as out-of-service assets that cannot be safely removed and pose a risk to the CVOW-C Export Cable Routes.

Boulder clearance may also be required in targeted locations to clear boulders along the Export Cable Routes, inter-array cable routes, and/or foundations prior to installation. Boulder removal can be performed using a combination of methods to optimize clearance of boulder debris of varying size and frequency. Removal is based on pre-surveys to identify location, size, and density of boulders. Surveys previously performed by Dominion Energy have indicated that no boulders over 0.5 m, or any other subsea obstructions, have been identified in the project area (Dominion Energy, 2023). If boulders are encountered during installation activities, Dominion Energy would move them from the Export Cable Routes, using either subsea grabs, or ploughs, and then relocate them to areas as close as possible to the original location of the undersea object (Dominion Energy, 2023). Boulder removal, if necessary to occur based on information obtained during pre-construction surveys, would be performed prior to the installation of the Export Cable Routes and would be completed by a support vessel. A boulder grab or a boulder plow may be used to complete boulder removal prior to installation. A boulder grab involves a grab most likely deployed from a dynamic positioning offshore support vessel being lowered to the seabed, over the targeted boulder. Once “grabbed”, the boulder is relocated away from the cable route and/or foundation location.

Boulder clearance using a boulder plow is completed by a high-bollard pull vessel, with a towed plow generally forming an extended V-shaped configuration, splaying from the rear of the main chassis. The V-shaped configuration displaces any boulders to the extremities of the plow, thus clearing the corridor. A tracked plow with a front blade similar to a bulldozer may also be used to push boulders away from the corridor. The size of boulders that can be relocated is dependent on a number of factors including the boulder weight, dimensions, embedment, density and ground conditions. Typically, boulders with dimensions less than 2.5 m (8 ft) can be relocated with standard tools and equipment.

Effects from seafloor preparation on marine mammals are expected to be short-term, low intensity, and unlikely to qualify as a take. Dredging, sandwave leveling, and boulder clearance is expected to be extremely localized at any given time, and NMFS expects that any marine mammals would not be exposed at levels or durations likely to disrupt behavioral patterns (

i.e.,

migrating, foraging, calving,

etc.

). Therefore, the potential for take of marine mammals to result from these activities is so low as to be discountable. Dominion Energy did not request and NMFS is not proposing to authorize any takes associated with seabed preparation activities; therefore, they are not analyzed further in this document.

Vessel Operation

Dominion Energy would utilize a variety of vessels to construct the CVOW-C project. Vessels may be used for direct installation or construction activities, surveys, protected species resource monitoring, and for crew and/or supply transfers. All route plans for all vessels would be designed to meet the industry guidelines and best practices in accordance with the International Chamber of Shipping guidance. All vessels would utilize Automatic Identification Systems (AIS) for all aspects of the project, as required by the United States Coast Guard. AIS would be required to monitor the number of vessels and traffic patterns for analysis and compliance with vessel speed requirements. All vessels will operate in accordance with applicable rules and regulations for maritime operation within U.S. Federal and state waters.

The largest vessels are expected to be used during the WTG installation phase with floating/jack-up crane barges, cable-laying vessels, supply/crew vessels, and/or associated tugs and barges transporting construction equipment and materials. Large work vessels (

e.g.,

jack-up installation vessels and DP cable-laying vessels) for WTG and OSS foundation installation will generally transit to the work location and remain in the area until installation is complete. These large vessels will move slowly over a short distance between work locations. In contrast, other vessels will travel between several ports and the Lease Area over the course of the construction period following mandatory vessel speed restrictions (see Proposed Mitigation section). These vessels will range in size from smaller crew transport boats to tug and barge vessels. However, construction crews responsible for assembling the WTGs will hotel onboard installation vessels at sea, thus limiting the number of crew vessel transits expected during the installation of the Lease Area.

While marine mammals may respond to the presence of a vessel, given the predictable movement and ubiquitous presence of vessels in the marine environment, and especially the variable sizes, which consist of smaller support vessels that are predominate during offshore wind development, exposure to transiting vessels would not generally be expected to result in the disruption of marine mammal behavioral patterns such that a take would occur. As part of various vessel-based construction activities, including cable laying and construction material delivery, dynamic positioning thrusters may be utilized to hold vessels in position or move slowly. Sound produced through use of dynamic positioning thrusters is similar to that produced by transiting vessels, and dynamic positioning thrusters are typically operated either in a similarly predictable manner or used for short durations around stationary activities. Construction-related vessel activity, including the use of dynamic positioning thrusters, is not expected to result in take of marine mammals. Dominion Energy did not request and NMFS does not propose to authorize any take associated with vessel activity.

Dominion Energy has executed a lease agreement for a portion of the existing Portsmouth Marine Terminal facility in the city of Portsmouth, Virginia, to serve as a Construction Port (Sections 1-3, Dominion Energy, 2023). The Construction Port would be used to stage and store the monopiles and relevant transition pieces and to stage and store and pre-assemble wind turbine generation components. Dominion Energy is also currently evaluating several alternatives to lease portions of existing port facilities in the Hampton Roads, Virginia area for an operation and maintenance facility for the CVOW-C proposed project. The preferred location is Lambert's Point, located on a brownfield site in Norfolk, Virginia, although existing facilities at the Virginia Port Authority's Portsmouth Marine Terminal or Newport News Marine Terminal may also be viable options. These ports will continue to assist Dominion Energy to support offshore construction, assembly and fabrication, crew transfers, and logistics.

Vessel types and usage estimated to occur during the entire five-year effective period of the proposed rule, if issued, is shown in Table 6. NMFS references the reader to Dominion Energy's COP for additional information on vessels planned for use during the CVOW-C proposed project (Dominion Energy, 2023).

Table 6—Proposed Project Vessel Use During the 5-Year CVOW-C Project

Vessel role

Vessel class

Number of vessels

Breadth

(ft)

Length

(ft)

Draft

(ft)

Days on project,

including spare

positions

Most likely

operating

period

Frequency of transit

Transit

destination

Scour Protection Installation

Fall Pipe Vessel

106

507

657

10/2023 to 12/2024 and 02/2025 to 10/2025

Weekly

Canada/USA.

Transport Monopile/Transition Pieces from U.S. Port to Installation Site

U.S. Barge

105

400

823

04/2024 to 12/2025

(188+17)/2 = 103 cycles in total for all barges

Portsmouth, VA.

Tugs for Monopile/Transition Piece Transport Barges

U.S. Ocean-going Tug

132

823

04/2024 to 12/2025

103 + 52 = 155 cycles in total

Portsmouth, VA.

Monopile/Transition Piece/Offshore Substation Installation

Heavy Lift Vessel (HLV)

161

711

804

04/2024 to 12/2025

Monthly

Europe/Hampton Roads, VA.

Noise Monitoring

Crew Transfer Vessel (CTV)

512

05/2024 to 10/2024 and 05/2025 to 10/2025

Daily

Portsmouth, VA.

Noise Mitigation

Platform Support Vessel

100

454

512

05/2024 to 10/2024 and 05/2025 to 10/2025

2 cycles in total + X due to bad weather

Portsmouth, VA.

Crew Transfer

CTV

822

04/2024 to 12/2025

Every 2

day

Portsmouth, VA.

Jacket Installation

DP HLV

161

710

Monthly

Europe/Hampton Roads, VA.

Noise Monitoring for Jacket Installation

Crew Transfer Vessel (CTV)

Daily

Portsmouth, VA.

Noise Mitigation for Jacket Installation

Platform Support Vessel

100

454

Daily

Portsmouth, VA.

Transport Jackets/TopSides From EU Port to Installation Site

HLV

138

568

186

11/2024 to 04/2025

3 cycles in total

Europe.

Assist Tugboat For Topside Installation

U.S. Ocean-going Tug

112

Daily

Hampton Roads, VA.

Offshore Cable Commissioning (Contingency Vessel)

DP2 JUV

230

132

288

11/2024 to 07/2025

N/A

N/A.

Nearshore Trenchless Installation

Drill Rig Spread

N/A

262

09/2023 to 02/2024

N/A (staged at the direct pipe punch-out locations)

Hampton Roads, VA.

Nearshore Marine Assistance

U.S. Multi Purpose Support Vessel (Multicat)

262

Weekly

Portsmouth, VA.

Nearshore Marine Assistance

U.S. Tug (Small)

112

262

Weekly

Portsmouth, VA.

Landfall

Landfall Beach Spread

N/A

523

01/2023 to 04/2024 and

Weekly

Hampton Roads, VA.

Shore Pull-in

U.S. Pull-in Support Barge

105

400

523

07/2024 to 09/2025

Weekly

Portsmouth, VA.

Shore Pull-in

U.S. Workboat (Tug)

132

523

Weekly

Portsmouth, VA.

Cable Lift Jack-Up Installation Vessel (Contingency Vessel)

JUV

105

144

Pre-lay Grapnel Run

Multipurpose Support Vessel

266

Weekly

Portsmouth, VA.

Pre-installation Survey

Survey Vessel

234

187

180

Weekly

Portsmouth, VA.

Cable Laying and Burial

Shallow-draft Cable Lay Vessel

110

401

523

Monthly

Europe/Hampton Roads, VA.

Anchor Handling

Multi Purpose Support Vessel (Multicat)

523

Daily

Hampton Roads, VA.

Transport Cable

Multi Purpose Support Vessel

289

131

Single Trip

Europe/Hampton Roads, VA.

Cable Burial

Hydroplow (Jetting)

523

N/A

Europe/Hampton Roads, VA.

Crew Transfer

CTV

523

Every 2nd Day

Portsmouth, VA.

As-built Survey

Survey Vessel

234

Weekly

Portsmouth, VA.

Pre-lay Survey (Offshore Export Cable)

Survey Vessel

180

1/2023 to 04/2024 and 08/2024 to 09/2025 and 11/2025 to 02/2026

Weekly

Portsmouth, VA.

Cable Laying and Burial (Offshore Export Cable)

Deep-draft Cable Lay Vessel

106

528

535

Monthly

Hampton Roads, VA.

Cable Laying and Burial (Offshore Export Cable)

Deep-draft Cable Lay Vessel

110

470

Monthly

Europe/Hampton Roads, VA.

Cable burial (Offshore Export Cable)

Trenching Support or Cable Laying Vessel

105

529

604

Monthly

Europe/Hampton Roads, VA-.

Cable burial (Offshore Export Cable)

Trenching Support or Cable Laying Vessel

112

561

605

Monthly

Europe/Hampton Roads, VA-.

Cable burial (Offshore Export Cable)

Burial Tool (Post-lay Jetting)

1,209

Monthly

Europe/Hampton Roads, VA-.

Offshore Jointing Vessel (Offshore Export Cable)

565

Monthly

Europe/Hampton Roads, VA.

Pre-lay Grapnel Run (Inter Array Cable)

Multipurpose Support Vessel

109

01/2023 to 04/2024 and 11/2024 to 05/2026

Weekly

Portsmouth, VA.

Pre-lay Survey (Inter-Array Cable)

Survey Vessel

Weekly

Portsmouth, VA.

Cable Laying and burial (Inter-Array Cable)

Deep-draft Cable Lay Vessel

106

528

558

Every 60 days

Europe/Hampton Roads, VA.

Multipurpose Service Vessel (Inter-Array Cable)

W2W

292

303

Monthly

Hampton Roads, VA.

Crew Transfer (Inter-Array Cable)

CTV

558

Every 2nd Day

Portsmouth, VA.

Cable Burial (Inter-Array Cable)

Trenching Support Vessel or Cable Laying Vessel

105

529

559

Every 60 days

Hampton Roads, VA.

Cable Burial (Inter-Array Cable)

Burial tool (Post-lay Jetting)

558

Every 60 days

Hampton Roads, VA.

As-built Survey (Inter-Array Cable)

Deep draft Cable Lay Vessel

106

528

Weekly

Portsmouth, VA.

WTG Installation

JUV

184

472

923

08/2025 to 02/2027

Vessel 1: Every 10-14 days Vessel 2: N/A

Vessel 1: Portsmouth, VA Vessel 2: N/A.

Transport WTGs from U.S. port to installation site

U.S. Barge

100

400

792

Approximately every 3 days

Portsmouth, VA.

Transport WTGs from U.S. Port to Installation Site

U.S. Ocean-going Tug

132

792

Approximately every 3 days

Portsmouth, VA.

Assist Tugboat

U.S. Ocean-going Tug

112

Approximately every 3 days

Hampton Roads, VA.

Commissioning Spread

Multi-role subsea Support Vessel with W2W

354

792

08/2025 to 04/2027

Bi-weekly

Portsmouth, VA.

Site Security

Safety vessel, Nearshore Trenchless Installation

Varies

1.8684

09/2023 to 08/2027

Bi-weekly

Portsmouth, VA.

Removing Sandwaves (Contingency Vessel)

Trailer Suction Hopper Dredger

480

117.6

2023

Daily

Portsmouth, VA.

Boulder Pickering (Contingency Vessel)

Anchor Handling Tug + Crane Barge

146

117.6

2023

Weekly

Portsmouth, VA.

Boulder Ploughing (Contingency Vessel)

Anchor Handling Tug + Towed Plow

190

157.2

2023

Weekly

Portsmouth, VA.

Crossing Protection (Concrete Mattresses)

Fall Pipe Vessel or Deep Draft Cable Lay Vessel

146

126

2024 to 2026

Between 2 and 27 cycles

Portsmouth, VA.

Note:

N/A means not applicable and—means the information was not provided by Dominion Energy.

While most of these vessels are planned for construction, not all would be used. However, NMFS has opted to include all possible vessels with all available information to provide the best possible understanding of what vessels may be involved in the CVOW-C proposed project.

Helicopter Usage

Dominion Energy may supplement vessel-based transport with helicopter usage to transfer crew to and from both the shore and the Lease Area (crew transfer vessels described in Table 6 above does not consider helicopter use and thus, is a conservative estimate). Helicopter usage would align with the best practices from the Federal Aviation Administration and other relevant stakeholders when determining routes and altitudes for travel. Helicopter use is expected primarily from 2024-2026 at a rate of up to four roundtrip flights per week, equating to 208 roundtrips annually and up to 624 roundtrips total. Project-related aircraft would only occur at low altitudes over water during takeoff and landing at an offshore location where one or more vessels are located. Helicopters produce sounds that can be audible to marine mammals; however, most sound energy from aircraft reflects off the air-water interface as only sound radiated downward within a 26-degree cone penetrates below the surface water (Urick, 1972). Due to the intermittent nature and the small area potentially ensonified by this sound source for a very limited duration, Dominion Energy did not request, and NMFS is not proposing to authorize take of marine mammals incidental to helicopter flights; therefore, this activity will not be discussed further in this proposed action.

Fisheries Monitoring Surveys

Dominion Energy plans to undertake fisheries monitoring surveys, in partnership with the Virginia Institute of Marine Sciences (VIMS), Atlantic surf clam (

Spisula solidissima

) fishers, black sea bass (

Centropristis striata

) fishers, whelk (

Buccinidae

spp.) fishers, Rutgers University, and the Virginia Marine Resource Commission (VMRC), as required by BOEM to support the regulatory filings for renewable energy projects proposed in the Atlantic Lease Areas (30 CFR 585.627(a)(3)). Fisheries monitoring surveys have been designed in accordance with recommendations set forth by the Responsible Offshore Science Alliance (ROSA) Offshore Wind Project Monitoring Framework and Guidelines (

https://www.rosascience.org/offshore-wind-and-fisheries-resources/

; ROSA, 2021), which is based extensively on existing BOEM guidance for providing information on fisheries during work related to offshore wind projects (

https://www.boem.gov/sites/default/files/renewable-energy-program/Regulatory-Information/BOEM-Fishery-Guidelines.pdf

; BOEM, 2019). Dominion Energy would sample black sea bass and whelks using pots with weighted groundlines and Atlantic surf clams using a novel dredge tow (designed by Rutgers University and other industry experts). The pot/trap surveys will have a two-day soak time. Dominion Energy will be using on-demand fishing systems aimed at reducing the entanglement risk to protected species. These systems include, but are not limited to, spooled systems, buoy and stowed systems, lift bag systems, and grappling (more information on these systems can be found at

https://www.fisheries.noaa.gov/new-england-

mid-atlantic/marine-mammal-protection/developing-viable-demand-gear-systems#:~:text=Line%20wrapped%20around%20a%20buoyant%20spool%20is%20tethered,retrieve%20it%2C%20and%20the%20gear%20on%20the%20string

). The survey tows completed by this dredge will be shorter than typical commercial tows. Dredge tows do not inherently have the potential to result in take of marine mammals. Pot-based surveys may, absent mitigation, result in the take of marine mammals. However, Dominion Energy would implement mitigation and monitoring measures to avoid taking marine mammals, including, but not limited to: monitoring for marine mammals before and during dredging and gear deployment activities, not deploying or pulling gear in certain circumstances, maintaining marine mammal watches at least 15 minute before to both the deployment and retrieval of the gear, and moving to a new sampling location if a marine mammal appears at risk of interactions with the gear. A full description of the mitigation measures can be found in the Proposed Mitigation section. Dominion Energy had also proposed to conduct trawl surveys; however, they subsequently removed trawling from their plans. Hence, trawl surveys would not occur.

With the implementation of these measures, Dominion Energy does not anticipate, and NMFS is not proposing, to authorize take of marine mammals incidental to fishery surveys. Given no take is anticipated from these surveys, impacts from fishery surveys will not be discussed further in this document aside from listing the required mitigation measures (see Proposed Mitigation section).

Description of Marine Mammals in the Area of Specified Activities

Thirty-nine marine mammal species under NMFS' jurisdiction have geographic ranges within the western North Atlantic OCS (Hayes

et al.,

2022), with six of these being protected under the Endangered Species Act (ESA). However, for reasons described below, Dominion Energy has requested and NMFS proposes to authorize take of only 21 species (comprising 22 stocks) of marine mammals. Sections 3 and 4 of Dominion Energy's application summarize available information regarding status and trends, distribution and habitat preferences, and behavior and life history of the potentially affected species (Dominion Energy, 2023). NMFS fully considered all of this information, and we refer the reader to these descriptions in the application, incorporated here by reference, instead of reprinting the information. Additional information regarding population trends and threats may be found in NMFS's Stock Assessment Reports (SARs;

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

Of the 39 marine mammal species and/or stocks with geographic ranges that include the CVOW-C project area found in the coastal and offshore waters of Virginia (Table 11 in Dominion Energy's ITA application), 17 are not expected to be present or are considered rare or unexpected in the project area based on sighting and distribution data; they are, therefore, not discussed further beyond the explanation provided here. Specifically, the following cetacean species are known to occur offshore of Virginia but are not expected to occur in the project area due to the location of preferred habitat outside the Lease Area and Export Cable Routes, based on the best available information: dwarf sperm whale (

Kogia sima

), Fraser's dolphin (

Lagenodelphis hosei

), killer whale (

Orcinus orca

), pygmy killer whale (

Feresa attenuata

), rough-toothed dolphin (

Steno bredanensis

), spinner dolphin (

Stenalla longirostris orientalis

), striped dolphin (

Stenella coeruleoalba

), white-beaked dolphin (

Lagenorhynchus albirostris

), Cuvier's beaked whale (

Ziphius cavirostris

), four species of Mesoplodont beaked whales (

Mesoplodon densitostris, M. europaeus, M. mirus, and M. bidens

), and the blue whale (

Balaenoptera musculus

). Two species of phocid pinnipeds are also uncommon in the CVOW-C project area, including: harp seals (

Pagophilus groenlandica

) and hooded seals (

Cystophora cristata

). In addition, the Florida manatees (

Trichechus manatus;

a sub-species of the West Indian manatee) has been previously documented as an occasional visitor to the Mid-Atlantic region during summer months (Morgan

et al.,

2002; Cummings

et al.,

2014). However, manatees are managed by the U.S. Fish and Wildlife Service (USFWS) and are not considered further in this document.

None of the aforementioned species were observed during HRG surveys conducted by Dominion Energy in and around Virginia from 2018-2021 based on monitoring reports received for previously issued high-resolution site characterization IHAs (85 FR 55415, September 8, 2020; 85 FR 81879, December 17, 2020; 86 FR 21298, April 22, 2021), for the construction of the CVOW Pilot Project (85 FR 30930, May 21, 2020) or Unexploded Ordnance/Munitions and Explosives of Concern (UXO/MEC)-specific surveys (83 FR 39062, August 8, 2018). However, four marine mammal species that might otherwise be considered rare were detected through PAM/visually observed by marine mammal monitors during work under these previous IHAs. These include: false killer whales (one acoustically detected, four observed), pygmy sperm whales (one acoustically detected, one observed), Clymene dolphin (five observed), and melon-headed whales (one acoustically detected, five recorded). Although these were detected in low numbers, these observations/detections did occur within locations near the CVOW-C project area where NMFS considers it reasonably likely that some individuals may be observed during the five-year effective period of the proposed rulemaking. Because of this, NMFS has proposed to authorize take of these species.

Table 7 lists all species and stocks for which take is expected and proposed to be authorized for this action, and summarizes information related to the population or stock, including regulatory status under the MMPA and Endangered Species Act (ESA) and potential biological removal (PBR) level, where known. 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)) and can be found in NMFS's SARs. While no mortality is anticipated or proposed for authorization here, PBR and annual serious injury and mortality from anthropogenic sources are included here as gross indicators of the status of the species and other threats.

Marine mammal abundance estimates presented in this document represent the total number of individuals that make up a given stock or the total number estimated within a particular study or survey area. NMFS'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 7 are the most recent available at

the time of publication and are available in NMFS' final 2021 SARs (Hayes

et al.,

2022) and draft 2022 SARs available online at:

https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports

Table 7—Marine Mammal Species

Likely to Occur Near the Project Area That May Be Taken by Dominion Energy's Proposed Activities

Common name

Scientific name

Stock

ESA/

MMPA

status;

strategic

(Y/N)

Stock

abundance

(CV, N

min

, most recent

abundance survey)

PBR

Annual

mortalities

or serious injuries

(M/SI)

Order Artiodactyla—Cetacea—Superfamily Mysticeti (baleen whales)

Family Balaenidae:

North Atlantic right whale

Eubalaena glacialis

Western Atlantic

E, D, Y

338 (0; 332; 2020)

0.7

8.1

Family Balaenopteridae (rorquals):

Fin whale

Balaenoptera physalus

Western North Atlantic

E, D, Y

6,802 (0.24; 5,573; 2016)

1.8

Humpback whale

Megaptera novaeangliae

Gulf of Maine

-, -, Y

1,396 (0; 1,380; 2016)

12.15

Minke whale

Balaenoptera acutorostrata

Canadian Eastern Coastal

-, -, N

21,968 (0.31; 17,002; 2016)

170

10.6

Sei whale

Balaenoptera borealis

Nova Scotia

E, D, Y

6,292 (1.02; 3,098; 2016)

6.2

0.8

Family Physeteridae:

Sperm whale

Physeter macrocephalus

North Atlantic

E, D, Y

4,349 (0.28; 3,451; 2016)

3.9

Family Kogiidae:

Pygmy sperm whale

Kogia breviceps

Western North Atlantic

-, -, N

7,750 (0.38; 5,689; 2016)

Family Delphinidae:

Atlantic spotted dolphin

Stenella frontalis

Western North Atlantic

-, -, N

39,921 (0.27; 32,032; 2016)

320

Atlantic white-sided dolphin

Lagenorhynchus acutus

Western North Atlantic

-, -, N

93,233 (0.71; 54,433; 2016)

544

Bottlenose dolphin

Tursiops truncatus

Western North Atlantic—Offshore

-, -, N

62,851 (0.23; 51,914; 2016)

519

Southern Migratory Coastal

-, -, Y

3,751 (0.6; 185; See SAR)

0-18.3

Clymene dolphin

Stenella clymene

Western North Atlantic

-, -, N

4,237 (1.03; 2,071; 2016)

Common dolphin

Delphinus delphis

Western North Atlantic

-, -, N

172,897 (0.21; 145,216; 2016)

1,452

390

False killer whale

Pseudorca crassidens

Western North Atlantic

-, -, N

1,791 (0.56; 1,154; 2016)

Melon-headed whale

Peponocephala electra

Western North Atlantic

-, -, N

UNK (UNK; UNK; 2016)

UNK

Long-finned pilot whale

Globicephala melas

Western North Atlantic

-, -, N

39,215 (0.3; 30,627; 2016)

306

Short-finned pilot whale

Globicephala macrorhynchus

Western North Atlantic

-, -, Y

28,924 (0.24, 23,637, See SAR)

236

136

Pantropical spotted dolphin

Stenella attenuata

Western North Atlantic

-, D, N

6,593 (0.52, 4,367, See SAR)

Risso's dolphin

Grampus griseus

Western North Atlantic

-, -, N

35,215 (0.19; 30,051; 2016)

301

Family Phocoenidae (porpoises):

Harbor porpoise

Phocoena phocoena

Gulf of Maine/Bay of Fundy

-, -, N

95,543 (0.31; 74,034; 2016)

851

Order Carnivora—Superfamily Pinnipedia

Family Phocidae (earless seals):

Gray seal

Halichoerus grypus

Western North Atlantic

-, -, N

27,300 (0.22; 22,785; 2016)

1,389

4,453

Harbor seal

Phoca vitulina

Western North Atlantic

-, -, N

61,336 (0.08; 57,637; 2018)

1,729

339

ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.

NMFS' marine mammal stock assessment reports can be found online at:

www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments

. CV is the coefficient of variation; N

min

is the minimum estimate of stock abundance. In some cases, CV is not applicable.

These values, found in NMFS' SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (

e.g.,

commercial fisheries, ship strike).

NMFS' stock abundance estimate (and associated PBR value) applies to the U.S. population only. Total stock abundance (including animals in Canada) is approximately 451,431. The annual M/SI value given is for the total stock.

Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy (

https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/

; Committee on Taxonomy (2022)).

Although both species are described here, the requested take for both short-finned and long-finned pilot whales has been summarized into a single group (pilot whales spp.).

While these species were not originally included in Dominion Energy's request, given recorded sightings/detections of these species during previous Dominion Energy IHAs in the same general area, NMFS has included these as species that may be harassed (by Level B harassment only) during the five-year effective period of this proposed rulemaking.

Estimate is for Kogia spp. only.

As indicated above, all 21 species and 22 stocks in Table 7 temporally and spatially co-occur with the activity to the degree that take is reasonably likely to occur. Four of the marine mammal species for which take is requested are listed as threatened or endangered under the ESA, including North Atlantic right, fin, sei, and sperm whales. In addition to what is included in Sections 3 and 4 of Dominion Energy's ITA application (

https://www.fisheries.noaa.gov/action/incidental-take-authorization-dominion-energy-virginia-construction-coastal-virginia

), the SARs (

https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments

), and NMFS' website (

https://www.fisheries.noaa.gov/species-directory/marine-mammals

), we provide further detail below informing the baseline for select species (

e.g.,

information regarding current Unusual Mortality Events (UME) and known important habitat areas, such as Biologically Important Areas (BIAs) (Van Parijs, 2015). There are no ESA-designated critical habitats for any species within the CVOW-C project area.

Under the MMPA, a UME is defined as “a stranding that is unexpected; involves a significant die-off of any marine mammal population; and demands immediate response” (16 U.S.C. 1421h(6)). As of April 13, 2023, five UMEs are considered active, with four of these occurring along the U.S. Atlantic coast for various marine mammal species; of these, the most relevant to the CVOW-C project are the North Atlantic right whale and the humpback whale, given the prevalence of these species in the project area. A more recent UME is active for the Northeast pinnipeds (harbor and gray seals) but has only been recorded in Maine, which is outside the project area. Two other UMEs, one for the Atlantic minke whale from 2017-2022 and one for the Northeast pinnipeds (harbor and gray seals) from 2018-2020, are considered non-active and are pending closure. More information on UMEs, including all active, closed, or pending, can be found on NMFS' website at

https://www.fisheries.noaa.gov/national/marine-life-distress/active-and-closed-unusual-mortality-events

Below we include information for a subset of the species that presently have an active or recently closed UME occurring along the Atlantic coast, or for which there is information available related to areas of biological significance. For the majority of species potentially present in the specific geographic region, NMFS has designated only a single generic stock (

e.g.,

“western North Atlantic”) for management purposes. This includes the “Canadian east coast” stock of minke whales, which includes all minke whales found in U.S. waters and is also a generic stock for management purposes. For humpback and sei whales, NMFS defines stocks on the basis of feeding locations,

i.e.,

Gulf of Maine and Nova Scotia, respectively. However, references to humpback whales and sei whales in this document refer to any individuals of the species that are found in the specific geographic region. Any areas of known biological importance (including the BIAs identified in La Brecque

et al.,

2015) that overlap spatially with the project area are addressed in the species sections below.

North Atlantic Right Whale

The North Atlantic right whale has been listed as Endangered since the ESA was enacted in 1973. They were recently uplisted from Endangered to Critically Endangered on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species (Cooke, 2020). The uplisting was due to a decrease in population size (Pace

et al.,

2017), an increase in vessel strikes and entanglements in fixed fishing gear (Knowlton

et al.,

2012; Daoust

et al.,

2017; Davis and Brillant, 2019; Sharp

et al.,

2019; Moore

et al.,

2021; Knowlton

et al.,

2022), and a decrease in birth rate (Pettis

et al.,

2021; Reed

et al.,

2022). The Western Atlantic stock is considered depleted under the MMPA (Hayes

et al.,

2022). There is a recovery plan (NOAA Fisheries, 2005) for the North Atlantic right whale, and NMFS completed 5-year reviews of the species in 2012,2017, and 2022 which concluded no change to the listing status is warranted.

The North Atlantic right whale population had only a 2.8 percent recovery rate between 1990 and 2011, and an overall abundance decline of 29.7 percent from 2011-2020 (Hayes

et al.,

2022). Since 2010, the North Atlantic right whale population has been in decline (Pace

et al.,

2017; Pace

et al.,

2021), with a 40 percent decrease in calving rate (Kraus

et al.,

2016; Moore

et al.,

2021). North Atlantic right whale calving rates dropped from 2017 to 2020, with zero births recorded during the 2017-2018 season. The 2020-2021 calving season had the first substantial calving increase in five years, with 20 calves born, followed by 15 calves during the 2021-2022 calving season. However, mortalities continue to outpace births, and best estimates indicate fewer than 100 reproductively active females remain in the population.

NMFS' regulations at 50 CFR 224.105 designated nearshore waters of the Mid-Atlantic Bight as Mid-Atlantic U.S. Seasonal Management Areas (SMAs) for right whales in 2008. These specific SMAs were developed to reduce the threat of collisions between ships and right whales around their migratory route and calving grounds. As mentioned previously, the Chesapeake Bay SMA is within the vicinity of the proposed project area (

https://apps-nefsc.fisheries.noaa.gov/psb/surveys/MapperiframeWithText.html

). The SMA is currently active from November 1 through April 30 of each year and may be used by right whales for migrating. As noted above in the Summary of Request section, NMFS is proposing changes to the North Atlantic right whale speed rule (87 FR 46921; August 1, 2022).

The proposed project area (456.5 km

) spatially overlaps a portion of the migratory corridor BIA (269,488 km

(66,591,935 acres)) within which right whales migrate south to calving grounds generally in November and December. A northward right whale migration into feeding areas north of the project area occurs in March and April (LaBrecque

et al.,

2015; Van Parijs

et al.,

2015). The proposed project area is also in the vicinity of the currently established November 1st through April 30th Chesapeake Bay SMA (73 FR 60173; October 10, 2008), which may be used by right whales for various activities, including migration. Due to the current status of North Atlantic right whales, and the overlap of the proposed CVOW-C project with areas of biological significance (

i.e.,

a migratory corridor), the potential impacts of the proposed project on right whales warrant particular attention.

In late fall, a portion of the right whale population (including pregnant females) typically departs the feeding grounds in the North Atlantic, moves south along the migratory corridor BIA, including through the proposed project area, to right whale calving grounds off Georgia and Florida. Right whales feed primarily on the copepod,

Calanus finmarchicus,

a species whose availability and distribution has changed both spatially and temporally over the last decade due to an oceanographic regime shift that has been ultimately linked to climate change (Meyer-Gutbrod

et al.,

2021; Record

et al.,

2019; Sorochan

et al.,

2019). This distribution change in prey availability has led to shifts in right whale habitat-use patterns over the same time period (Davis

et al.,

2020;

Meyer-Gutbrod

et al.,

2022; Quintano-Rizzo

et al.,

2021, O'Brien

et al.,

2022) with reduced use of foraging habitats in the Great South Channel and Bay of Fundy and increased use of habitats within Cape Cod Bay and a region south of Martha's Vineyard and Nantucket Islands (Stone

et al.,

2017; Mayo

et al.,

2018; Ganley

et al.,

2019; Record

et al.,

2019; Meyer-Gutbrod

et al.,

2021); these foraging habitats are all located several hundred kilometers north of the project area. Passive acoustic monitoring data demonstrates that since 2010, North Atlantic right whale use of the mid-Atlantic and southeast has increased (Davis

et al.,

2017). Observations of these transitions in right whale habitat use, variability in seasonal presence in identified core habitats, and utilization of habitat outside of previously focused survey effort prompted the formation of a NMFS' Expert Working Group, which identified current data collection efforts, data gaps, and provided recommendations for future survey and research efforts (Oleson

et al.,

2020). Recent research indicates understanding of their movement patterns remains incomplete and not all of the population undergoes a consistent annual migration (Davis

et al.,

2017; Gowan

et al.,

2019; Krzystan

et al.,

2018). Non-calving females may remain in the feeding grounds, during the winter in the years preceding and following the birth of a calf to increase their energy stores (Gowen

et al.,

2019).

North Atlantic right whale presence within the CVOW-C project area is predominantly seasonal with individuals likely to be transient and migrating through the area. The highest density months for North Atlantic right whales in this area are November through April, however, mitigation measures include a restriction on pile driving during this time period. Right whales have also been acoustically detected off coastal Virginia year-round with detections during the late fall (October-December) and late winter/early spring (February-March) (Salisbury

et al.,

2016). Density data from Roberts and Halpin (2022) confirm, of the months planned for construction (May through October), the highest average density of right whales in the CVOW-C project area occurs in May (0.00015 individuals/km

). However, based upon sightings and acoustic detections, right whales are likely to be present to some degree in or near the proposed project area throughout the year (Salisbury

et al.,

2016; Davis et al., 2017; Cotter, 2019), though we do not expect that the right whale presence would be in the larger numbers typically associated with a foraging or calving ground.

Elevated right whale mortalities have occurred since June 7, 2017, along the U.S. and Canadian coast, with the leading category for the cause of death for this UME determined to be “human interaction,” specifically from entanglements or vessel strikes. As of April 13, 2023, there have been 36 confirmed mortalities (dead stranded or floaters), 0 pending mortalities, and 33 seriously injured free-swimming whales for a total of 69 whales. As of October 14, 2022, the UME also considers animals (n=29) with sub-lethal injury or illness (called “morbidity”) bringing the total number of whales in the UME to 98. Approximately 42 percent of the population is known to be in reduced health (Hamilton

et al.,

2021), likely contributing to smaller body sizes at maturation, making them more susceptible to threats and reducing fecundity (Moore

et al.,

2021; Reed

et al.,

2022; Stewart

et al.,

2022). More information about the North Atlantic right whale UME is available online at:

www.fisheries.noaa.gov/national/marine-life-distress/2017-2021-north-atlantic-right-whale-unusual-mortality-event.

Humpback Whale

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

On September 8, 2016, NMFS divided the once single species into 14 distinct population segments (DPS), removed the species-level listing, and, in its place, listed four DPSs as endangered and one DPS as threatened (81 FR 62259; September 8, 2016). The remaining nine DPSs were not listed. The West Indies DPS, which is not listed under the ESA, is the only DPS of humpback whales that is expected to occur in the project area. Bettridge

et al.

(2015) estimated the size of the West Indies DPS population at 12,312 (95 percent confidence interval (CI) 8,688-15,954) whales in 2004-05, which is consistent with previous population estimates of approximately 10,000-11,000 whales (Smith

et al.,

1999; Stevick

et al.,

2003) and the increasing trend for the West Indies DPS (Bettridge

et al.,

2015).

Humpback whales are migratory off coastal Virginia, moving seasonally between northern feeding grounds in New England and southern calving grounds in the West Indies (Hayes

et al.,

2022). However, not all humpback whales migrate to the Caribbean during the winter as individuals are sighted in mid- to high-latitude areas during this season (Swingle

et al.,

1993; Davis

et al.,

2020). In addition to a migratory pathway, the mid-Atlantic region also represents a supplemental winter feeding ground for juveniles and mature whales (Barco

et al.,

2002). Records of humpback whales off the U.S. mid-Atlantic coast (New Jersey south to North Carolina) suggest that these waters are used as a winter feeding ground from December through March (Mallette

et al.,

2017; Barco

et al.,

2002; LaBrecque

et al.,

2015) and represent important habitat for juveniles, in particular (Swingle

et al.,

1993; Wiley

et al.,

1995). Mallette

et al.

(2017) documented site fidelity of individual humpback whales to coastal Virginia waters across seasons and years from 2012-2017. Based upon the analysis of stomach contents from humpback whales that have previously stranded in the coastal Virginia area, whales may feed upon Atlantic menhaden and bay anchovy off coastal Virginia (Mallette

et al.,

2017).

Since January 2016, elevated humpback whale mortalities along the Atlantic coast from Maine to Florida led to the declaration of a UME. Partial or full necropsy examinations have been conducted on approximately half of the 191 known cases (as of April 13, 2023). Of the whales examined (approximately 90), about 40 percent had evidence of human interaction, either ship strike or entanglement (

https://www.fisheries.noaa.gov/national/marine-life-distress/2016-2023-humpback-whale-unusual-mortality-event-along-atlantic-coast

). While a portion of the whales have shown evidence of pre-mortem vessel strike, this finding is not consistent across all whales examined and more research is needed. NOAA is consulting with researchers that are conducting studies on the humpback whale populations, and these efforts may provide information on changes in whale distribution and habitat use that could provide additional insight into how these vessel interactions occurred. More information is available at:

https://www.fisheries.noaa.gov/national/marine-life-distress/2016-2023-humpback-whale-unusual-mortality-event-along-atlantic-coast

Since December 1, 2022, the number of humpback strandings along the mid-Atlantic coast, including Virginia off Virginia Beach, 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. Along the New York/New Jersey/Virginia shore, these whales may be following their prey which are reportedly close to shore in the winter. These prey also attract fish that are of interest to recreational and commercial fishermen. This increases the number of boats in these areas. More whales in the water in areas traveled by boats of all sizes increases the risk of vessel strikes. Vessel strikes and entanglement in fishing gear are the greatest human threats to large whales.

Fin Whale

Fin whales frequently occur in the waters of the U.S. Atlantic Exclusive Economic Zone (EEZ), principally from Cape Hatteras, North Carolina northward and are distributed in both continental shelf and deep water habitats (Hayes

et al.,

2022). Although fin whales are present north of the 35-degree latitude region in every season and are broadly distributed throughout the western North Atlantic for most of the year, densities vary seasonally (Edwards

et al.,

2015; Hayes

et al.,

2022). Acoustic detections suggest year-round presence in Virginia waters, with the greatest number of detections occurring from August through April (Davis

et al.,

2020). Acoustic observations of fin whale singers from both the Atlantic Continental Shelf and deep-ocean areas provide evidence of fin whale singing throughout these regions year-round and support the conclusion that male fin whales are broadly distributed throughout the western North Atlantic for most of the year (Watkins

et al.,

1987; Clark and Gagnon, 2002; Morano

et al.,

2012; Davis

et al.,

2020; Hayes

et al.,

2022).

The New England area represents a major feeding ground for fin whales, with two known foraging BIAs in the general area. Fin whales typically feed in the Gulf of Maine and the waters surrounding New England, but their mating and calving (and general wintering) areas are largely unknown (Hain

et al.,

1992, Hayes

et al.,

2022). Hain

et al.

(1992) suggested calving occurs in the mid-Atlantic region from October through January, yet this remains to be confirmed. However, given the more southerly location of the Virginia Lease Area (located approximately 516 km (320.6 mi) away from the Montauk Point BIA (2,933 km

(724,760.1 acres); Hain

et al.,

1992; LaBrecque

et al.,

2015) and approximately 695 km (431.9 mi) from the southern Gulf of Maine BIA (18,015 km

; 4,451,603.4 acres). Therefore, there would be no overlap from the CVOW-C project with either of the fin whale feeding BIAs.

Minke Whale

Minke whales are common and widely distributed throughout the U.S. Atlantic EEZ (Cetacean and Turtle Assessment Program (CETAP), 1982; Hayes

et al.,

2022), although their distribution has a strong seasonal component. Individuals have often been detected acoustically in shelf waters from spring to fall and more often detected in deeper offshore waters from winter to spring (Risch

et al.,

2013). Minke whales are abundant in New England waters from May through September (Pittman

et al.,

2006; Waring

et al.,

2014), yet largely absent from these areas during the winter, suggesting the possible existence of a migratory corridor (LaBrecque

et al.,

2015). A migratory route for minke whales transiting between northern feeding grounds and southern breeding areas may exist to the east of the proposed project area, as minke whales may track warmer waters along the continental shelf while migrating (Risch

et al.,

2014). Overall, minke whale use of the project area is likely highest during winter months when foundation installation would not be occurring. No mating or calving grounds have been identified along the U.S. Atlantic coast (LaBrecque

et al.,

2015).

There are two minke whale feeding BIAs identified in the southern and southwestern section of the Gulf of Maine, including Georges Bank, the Great South Channel, Cape Cod Bay and Massachusetts Bay, Stellwagen Bank, Cape Anne, and Jeffreys Ledge from March through November, annually (LeBrecque

et al.,

2015). However, these BIAs are located north of the CVOW-C project area, at approximately 656 km (407.6 mi) from the CVOW-C project area to the most southern BIA and would not overlap the CVOW-C project area.

Since January 2017, elevated minke whale mortalities detected along the Atlantic coast from Maine through South Carolina resulted in the declaration of a UME. As of April 13, 2023, a total of 142 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. This UME has been declared non-active and is pending closure. More information is available at:

https://www.fisheries.noaa.gov/national/marine-life-distress/2017-2022-minke-whale-unusual-mortality-event-along-atlantic-coast

Sei Whale

The Nova Scotia stock of sei whales can be found in deeper waters of the continental shelf edge of the eastern United States and northeastward to south of Newfoundland (Mitchell, 1975; Hain

et al.,

1985; Hayes

et al.,

2022). During spring and summer, the stock is mainly concentrated in northern feeding areas, including the Scotian Shelf (Mitchell and Chapman, 1977), the Gulf of Maine, Georges Bank, the Northeast Channel, and south of Nantucket (CETAP, 1982; Kraus

et al.,

2016; Roberts

et al.,

2016; Palka

et al.,

2017; Cholewiak

et al.,

2018; Hayes

et al.,

2022). Sei whales have been detected acoustically along the Atlantic Continental Shelf and Slope from south of Cape Hatteras, North Carolina to the Davis Strait, with acoustic occurrence increasing in the mid-Atlantic region since 2010 (Davis

et al.,

2020). Although their migratory movements are not well understood, sei whales are believed to migrate north in June and July to feeding areas and south in September and October to breeding areas (Mitchell, 1975; CETAP, 1982; Davis

et al.,

2020). Davis

et al.

(2020) acoustically detected sei whales in offshore waters of the mid-Atlantic region during the winter months. Very few sei whales were detected in the mid-Atlantic during the summer (the primary time of year when foundation installation would be occurring), with the exception of a detection that lasted for two days off Virginia. Although sei whales generally occur offshore, individuals may also move into shallower, more inshore waters (Payne

et al.,

1990; Halpin

et al.,

2009; Hayes

et al.,

2022).

A sei whale feeding BIA occurs in New England waters from May through November (LaBrecque

et al.,

2015). This BIA is located approximately 600 km (372.8 mi) northeast of the project area and is not expected to be impacted by project activities related to CVOW-C.

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 has been declared a UME. Preliminary testing of samples has found some harbor and gray seals positive for highly pathogenic avian influenza. While the UME is not occurring in the CVOW-C project area, the populations affected by the UME are the same as those potentially affected by the project.

However, due to the two states being approximately 677.6 km (421 mi) apart, by water (from the most northern point of Virginia to the most southern point of Maine), NMFS does not expect that this UME would be further conflated by the proposed activities related to the CVOW-C project. Information on this UME is available online at:

https://www.fisheries.noaa.gov/2022-2023-pinniped-unusual-mortality-event-along-maine-coast

The above event was preceded by a different UME, occurring from 2018-2020 (closure of the 2018-2020 UME is pending). Beginning in July 2018, elevated numbers of harbor seal and gray seal mortalities occurred across Maine, New Hampshire, and Massachusetts. Additionally, stranded seals have shown clinical signs as far south as Virginia, although not in elevated numbers, therefore the UME investigation encompassed all seal strandings from Maine to Virginia. A total of 3,152 reported strandings (of all species) occurred from July 1, 2018, through March 13, 2020. Full or partial necropsy examinations have been conducted on some of the seals and samples have been collected for testing. Based on tests conducted thus far, the main pathogen found in the seals is phocine distemper virus. NMFS is performing additional testing to identify any other factors that may be involved in this UME, which is pending closure. Information on this UME is available online at:

https://www.fisheries.noaa.gov/new-england-mid-atlantic/marine-life-distress/2018-2020-pinniped-unusual-mortality-event-along

Marine Mammal Hearing

Hearing is the most important sensory modality for marine mammals underwater, and exposure to anthropogenic sound can have deleterious effects. To appropriately assess the potential effects of exposure to sound, it is necessary to understand the frequency ranges marine mammals are able to hear. Current data indicate that not all marine mammal species have equal hearing capabilities (

e.g.,

Richardson

et al.,

1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall

et al.

(2007) recommended that marine mammals be divided into functional hearing groups based on directly measured or estimated hearing ranges on the basis of available behavioral response data, audiograms derived using auditory evoked potential techniques, anatomical modeling, and other data. Note that no direct measurements of hearing ability have been successfully completed for mysticetes (

i.e.,

low-frequency cetaceans). Subsequently, NMFS (2018) described generalized hearing ranges for these marine mammal hearing groups. Generalized hearing ranges were chosen based on the approximately 65 decibel (dB) threshold from the normalized composite audiograms, with the exception for lower limits for low-frequency cetaceans where the lower bound was deemed to be biologically implausible and the lower bound from Southall

et al.

(2007) retained. Marine mammal hearing groups and their associated hearing ranges are provided in Table 8.

Table 8—Marine Mammal Hearing Groups

[NMFS, 2018]

Hearing group

Generalized hearing range *

Low-frequency (LF) cetaceans (baleen whales)

7 Hz to 35 kHz.

Mid-frequency (MF) cetaceans (dolphins, toothed whales, beaked whales, bottlenose whales)

150 Hz to 160 kHz.

High-frequency (HF) cetaceans (true porpoises,

Kogia,

river dolphins, cephalorhynchid,

Lagenorhynchus cruciger

L. australis

)

275 Hz to 160 kHz.

Phocid pinnipeds (PW) (underwater) (true seals)

50 Hz to 86 kHz.

* Represents the generalized hearing range for the entire group as a composite (

i.e.,

all species within the group), where individual species' hearing ranges are typically not as broad. Generalized hearing range chosen based on ~65 dB threshold from normalized composite audiogram, with the exception for lower limits for LF cetaceans (Southall

et al.,

2007) and PW pinniped (approximation).

The pinniped functional hearing group was modified from Southall

et al.

(2007) on the basis of data indicating that phocid species have consistently demonstrated an extended frequency range of hearing compared to otariids, especially in the higher frequency range (Hemilä

et al.,

2006; Kastelein

et al.,

2009; Reichmuth and Holt, 2013).

For more detail concerning these groups and associated frequency ranges, please see NMFS (2018) for a review of available information. Twenty-one marine mammal species (19 cetacean species (5 mysticetes and 14 odontocetes) and 2 pinniped species (both phocid), consisting of 22 total stocks) have the reasonable potential to co-occur with the proposed project activities (Table 7).

NMFS notes that in 2019, Southall

et al.

recommended new names for hearing groups that are widely recognized. However, this new hearing group classification does not change the weighting functions or acoustic thresholds (

i.e.,

the weighting functions and thresholds in Southall

et al.

(2019) are identical to NMFS 2018 Revised Technical Guidance). When NMFS updates our Technical Guidance, we will be adopting the updated Southall

et al.

(2019) hearing group classification.

Potential Effects of Specified Activities on Marine Mammals and Their Habitat

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

Dominion Energy has requested authorization to take marine mammals incidental to construction activities associated within the CVOW-C project area. In the ITA application, Dominion Energy presented analyses of potential impacts to marine mammals from use of acoustic sources. NMFS carefully reviewed the information provided by Dominion Energy and independently

reviewed applicable scientific research and literature and other information to evaluate the potential effects of Dominion Energy's activities on marine mammals.

The proposed activities include the placement of up to 179 permanent foundations (176 WTGs and 3 OSSs), temporary nearshore cable landfall activities (

i.e.,

cofferdams and goal posts), and site characterization surveys (

i.e.,

HRG surveys). There are a variety of types and degrees of effects to marine mammals, prey species, and habitat that could occur as a result of the project. Below we provide a brief description of the types of sound sources that would be used in the project, the types of impacts that can potentially result from these sources and types of activities, and a brief discussion of the anticipated impacts on marine mammals from the CVOW-C project specifically, with consideration of the proposed mitigation measures.

Description of Sound Sources

This section contains a brief technical background on sound, on the characteristics of certain sound types, and on metrics used in this proposal inasmuch as the information is relevant to the specified activity and to a discussion of the potential effects of the specified activity on marine mammals found later in this document. For general information on sound and its interaction with the marine environment, please see,

e.g.,

Au and Hastings (2008); Richardson

et al.

(1995); Urick (1983) as well as the Discovery of Sound in the Sea (DOSITS) website at

https://dosits.org/

Sound is a vibration that travels as an acoustic wave through a medium such as a gas, liquid or solid. Sound waves alternately compress and decompress the medium as the wave travels. These compressions and decompressions are detected as changes in pressure by aquatic life and man-made sound receptors such as hydrophones (underwater microphones). In water, sound waves radiate in a manner similar to ripples on the surface of a pond and may be either directed in a beam (narrow beam or directional sources) or sound beams may radiate in all directions (omnidirectional sources).

Sound travels in water more efficiently than almost any other form of energy, making the use of acoustics ideal for the aquatic environment and its inhabitants. In seawater, sound travels at roughly 1,500 meters per second (m/s). In air, sound waves travel much more slowly at about 340 m/s. However, the speed of sound can vary by a small amount based on characteristics of the transmission medium such as water temperature and salinity.

The basic components of a sound wave are frequency, wavelength, velocity, and amplitude. Frequency is the number of pressure waves that pass by a reference point per unit of time and is measured in Hz or cycles per second. Wavelength is the distance between two peaks or corresponding points of a sound wave (length of one cycle). Higher frequency sounds have shorter wavelengths than lower frequency sounds and typically attenuate (decrease) more rapidly except in certain cases in shallower water. The intensity (or amplitude) of sounds are measured in decibels (dB), which are a relative unit of measurement that is used to express the ratio of one value of a power or field to another. Decibels are measured on a logarithmic scale, so a small change in dB corresponds to large changes in sound pressure. For example, a 10 dB increase is a ten-fold increase in acoustic power. A 20 dB increase is then a 100-fold increase in power and a 30 dB increase is a 1000-fold increase in power. However, a ten-fold increase in acoustic power does not mean that the sound is perceived as being 10 times louder. Decibels are a relative unit comparing two pressures; therefore, a reference pressure must always be indicated. For underwater sound, this is 1 microPascal (μPa). For in-air sound, the reference pressure is 20 microPascal (μPa). The amplitude of a sound can be presented in various ways; however, NMFS typically considers three metrics.

Sound exposure level (SEL) represents the total energy in a stated frequency band over a stated time interval or event and considers both amplitude and duration of exposure (represented as dB re 1 μPa2-s). SEL is a cumulative metric; it can be accumulated over a single pulse (for pile driving this is often referred to as single-strike SEL; SELss) or calculated over periods containing multiple pulses (SEL

cum

). Cumulative SEL represents the total energy accumulated by a receiver over a defined time window or during an event. The SEL metric is useful because it allows sound exposures of different durations to be related to one another in terms of total acoustic energy. The duration of a sound event and the number of pulses, however, should be specified as there is no accepted standard duration over which the summation of energy is measured. Sounds are typically classified by their spectral and temporal properties.

Root mean square (rms) is the quadratic mean sound pressure over the duration of an impulse. Root mean square is calculated by squaring all of the sound amplitudes, averaging the squares, and then taking the square root of the average (Urick, 1983). Root mean square accounts for both positive and negative values; squaring the pressures makes all values positive so that they may be accounted for in the summation of pressure levels (Hastings and Popper, 2005). This measurement is often used in the context of discussing behavioral effects, in part because behavioral effects, which often result from auditory cues, may be better expressed through averaged units than by peak pressures.

Peak sound pressure (also referred to as zero-to-peak sound pressure or 0-pk) is the maximum instantaneous sound pressure measurable in the water at a specified distance from the source, and is represented in the same units as the rms sound pressure. Along with SEL, this metric is used in evaluating the potential for PTS (permanent threshold shift) and TTS (temporary threshold shift).

Sounds can be either impulsive or non-impulsive. The distinction between these two sound types is important because they have differing potential to cause physical effects, particularly with regard to hearing (

e.g.,

Ward, 1997 in Southall

et al.,

2007). Please see NMFS

et al.

(2018) and Southall

et al.

(2007, 2019) for an in-depth discussion of these concepts. Impulsive sound sources (

e.g.,

airguns, explosions, gunshots, sonic booms, impact pile driving) produce signals that are brief (typically considered to be less than 1 second), broadband, atonal transients (American National Standards Institute (ANSI), 1986, 2005; Harris, 1998; National Institute for Occupational Safety and Health (NIOSH), 1998; International Organization for Standardization (ISO), 2003) and occur either as isolated events or repeated in some succession. Impulsive sounds are all characterized by a relatively rapid rise from ambient pressure to a maximal pressure value followed by a rapid decay period that may include a period of diminishing, oscillating maximal and minimal pressures, and generally have an increased capacity to induce physical injury as compared with sounds that lack these features. Impulsive sounds are typically intermittent in nature.

Non-impulsive sounds can be tonal, narrowband, or broadband, brief or prolonged, and may be either continuous or intermittent (ANSI, 1995; NIOSH, 1998). Some of these non-impulsive sounds can be transient signals of short duration but without the essential properties of pulses (

e.g.,

rapid rise time). Examples of non-impulsive

sounds include those produced by vessels, aircraft, machinery operations such as drilling or dredging, vibratory pile driving, and active sonar systems.

Sounds are also characterized by their temporal component. Continuous sounds are those whose sound pressure level remains above that of the ambient sound with negligibly small fluctuations in level (NIOSH, 1998; ANSI, 2005) while intermittent sounds are defined as sounds with interrupted levels of low or no sound (NIOSH, 1998). NMFS identifies Level B harassment thresholds based on if a sound is continuous or intermittent.

Even in the absence of sound from the specified activity, the underwater environment is typically loud due to ambient sound, which is defined as environmental background sound levels lacking a single source or point (Richardson

et al.,

1995). The sound level of a region is defined by the total acoustical energy being generated by known and unknown sources. These sources may include physical (

e.g.,

wind and waves, earthquakes, ice, atmospheric sound), biological (

e.g.,

sounds produced by marine mammals, fish, and invertebrates), and anthropogenic (

e.g.,

vessels, dredging, construction) sound. A number of sources contribute to ambient sound, including wind and waves, which are a main source of naturally occurring ambient sound for frequencies between 200 Hz and 50 kHz (International Council for the Exploration of the Sea (ICES), 1995). In general, ambient sound levels tend to increase with increasing wind speed and wave height. Precipitation can become an important component of total sound at frequencies above 500 Hz and possibly down to 100 Hz during quiet times. Marine mammals can contribute significantly to ambient sound levels as can some fish and snapping shrimp. The frequency band for biological contributions is from approximately 12 Hz to over 100 kHz. Sources of ambient sound related to human activity include transportation (surface vessels), dredging and construction, oil and gas drilling and production, geophysical surveys, sonar, and explosions. Vessel noise typically dominates the total ambient sound for frequencies between 20 and 300 Hz. In general, the frequencies of anthropogenic sounds are below 1 kHz, and if higher frequency sound levels are created, they attenuate rapidly.

The sum of the various natural and anthropogenic sound sources that comprise ambient sound at any given location and time depends not only on the source levels (as determined by current weather conditions and levels of biological and human activity) but also on the ability of sound to propagate through the environment. In turn, sound propagation is dependent on the spatially and temporally varying properties of the water column and sea floor and is frequency-dependent. As a result of the dependence on a large number of varying factors, ambient sound levels can be expected to vary widely over both coarse and fine spatial and temporal scales. Sound levels at a given frequency and location can vary by 10-20 dB from day to day (Richardson

et al.,

1995). The result is that, depending on the source type and its intensity, sound from the specified activity may be a negligible addition to the local environment or could form a distinctive signal that may affect marine mammals. Underwater ambient sound in the Atlantic Ocean offshore of Virginia comprises sounds produced by a number of natural and anthropogenic sources. Human-generated sound is a significant contributor to the acoustic environment in the project location.

Pile driving sounds are broadband, omni-directional sound sources. Pile driving noise has the potential to result in harassment to marine mammals if the animal is close enough to the sound source (with the distances necessary to cause harassment dependent on source levels and transmission loss rates). HRG sources; however, are more complex as they vary widely (

e.g.,

side scan sonars, sub-bottom profilers, boomers, and sparkers). Recently, Ruppel

et al.

(2022) categorized HRG sources into four tiers based on their potential to affect marine animals. All HRG sources proposed for use by Dominion Energy fall into the Tier 3 or Tier 4 category (note Tier 1 is the most impactful category containing high-energy airguns). Tier 4 includes most high-resolution geophysical, oceanographic, and communication/tracking sources, which are considered unlikely to result in incidental take of marine mammals and therefore termed

de minimis.

Tier 3 covers most remaining non-airgun seismic sources, which either have characteristics that do not meet the

de minimis

category (

e.g.,

some sparkers), but have anticipated impacts less than airguns and for which additional mitigation may in some cases be able to avoid the likelihood of take, or could not be fully evaluated in the paper (

e.g.,

bubble guns, some boomers). Some sparkers fell into Tier 3, as the study found that most sparkers lack the frequency, beamwidth, and degree of exposure characteristics to automatically meet the

de minimis

criteria.

Potential Effects of Underwater Sound on Marine Mammals and Their Habitat

Anthropogenic sounds cover a broad range of frequencies and sound levels and can have a range of highly variable impacts on marine life from none or minor to potentially severe responses depending on received levels, duration of exposure, behavioral context, and various other factors. Broadly, underwater sound from active acoustic sources, such as those in the CVOW-C project, can potentially result in one or more of the following: temporary or permanent hearing impairment, non-auditory physical or physiological effects, behavioral disturbance, stress, and masking (Richardson

et al.,

1995; Gordon

et al.,

2003; Nowacek

et al.,

2007; Southall

et al.,

2007; Götz

et al.,

2009). Non-auditory physiological effects or injuries that theoretically might occur in marine mammals exposed to high level underwater sound or as a secondary effect of extreme behavioral reactions (

e.g.,

change in dive profile as a result of an avoidance reaction) caused by exposure to sound include neurological effects, bubble formation, resonance effects, and other types of organ or tissue damage (Cox

et al.,

2006; Southall

et al.,

2007; Zimmer and Tyack, 2007; Tal

et al.,

2015).

In general, the degree of effect of an acoustic exposure is intrinsically related to the signal characteristics, received level, distance from the source, and duration of the sound exposure, in addition to the contextual factors of the receiver (

e.g.,

behavioral state at time of exposure, age class,

etc.

). In general, sudden, high level sounds can cause hearing loss as can longer exposures to lower level sounds. Moreover, any temporary or permanent loss of hearing will occur almost exclusively for noise within an animal's hearing range. We describe below the specific manifestations of acoustic effects that may occur based on the activities proposed by Dominion Energy.

Richardson

et al.

(1995) described zones of increasing intensity of effect that might be expected to occur in relation to distance from a source and assuming that the signal is within an animal's hearing range. First (at the greatest distance) is the area within which the acoustic signal would be audible (potentially perceived) to the animal but not strong enough to elicit any overt behavioral or physiological response. The next zone (closer to the receiving animal) corresponds with the area where the signal is audible to the animal and of sufficient intensity to elicit behavioral or physiological responsiveness. The third is a zone

within which, for signals of high intensity, the received level is sufficient to potentially cause discomfort or tissue damage to auditory or other systems. Overlaying these zones to a certain extent is the area within which masking (

i.e.,

when a sound interferes with or masks the ability of an animal to detect a signal of interest that is above the absolute hearing threshold) may occur; the masking zone may be highly variable in size.

Below, we provide additional detail regarding potential impacts on marine mammals and their habitat from noise in general, starting with hearing impairment, as well as from the specific activities Dominion Energy plans to conduct, to the degree it is available (noting that there is limited information regarding the impacts of offshore wind construction on marine mammals).

Hearing Threshold Shift

Marine mammals exposed to high-intensity sound or to lower-intensity sound for prolonged periods can experience hearing threshold shift (TS), which NMFS defines as a change, usually an increase, in the threshold of audibility at a specified frequency or portion of an individual's hearing range above a previously established reference level expressed in decibels (NMFS, 2018). Threshold shifts can be permanent, in which case there is an irreversible increase in the threshold of audibility at a specified frequency or portion of an individual's hearing range or temporary, in which there is reversible increase in the threshold of audibility at a specified frequency or portion of an individual's hearing range and the animal's hearing threshold would fully recover over time (Southall

et al.,

2019). Repeated sound exposure that leads to TTS could cause PTS.

When PTS occurs, there can be physical damage to the sound receptors in the ear (

i.e.,

tissue damage) whereas TTS represents primarily tissue fatigue and is reversible (Henderson

et al.,

2008). In addition, other investigators have suggested that TTS is within the normal bounds of physiological variability and tolerance and does not represent physical injury (

e.g.,

Ward, 1997; Southall

et al.,

2019). Therefore, NMFS does not consider TTS to constitute auditory injury.

Relationships between TTS and PTS thresholds have not been studied in marine mammals, and there is no PTS data for cetaceans. 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.,

2019). Given the higher level of sound or longer exposure duration necessary to cause PTS as compared with TTS, PTS is less likely to occur as a result of these activities, but it is possible and a small amount has been proposed for authorization for several species.

TTS is the mildest form of hearing impairment that can occur during exposure to sound, with a TTS of 6 dB considered the minimum threshold shift clearly larger than any day-to-day or session-to-session variation in a subject's normal hearing ability (Schlundt

et al.,

2000; Finneran

et al.,

2000; Finneran

et al.,

2002). While experiencing TTS, the hearing threshold rises, and a sound must be at a higher level in order to be heard. In terrestrial and marine mammals, TTS can last from minutes or hours to days (in cases of strong TTS). In many cases, hearing sensitivity recovers rapidly after exposure to the sound ends. There is data on sound levels and durations necessary to elicit mild TTS for marine mammals, but recovery is complicated to predict and dependent on multiple factors.

Marine mammal hearing plays a critical role in communication with conspecifics, and interpretation of environmental cues for purposes such as predator avoidance and prey capture. Depending on the degree (elevation of threshold in dB), duration (

i.e.,

recovery time), and frequency range of TTS, and the context in which it is experienced, TTS can have effects on marine mammals ranging from discountable to serious depending on the degree of interference of marine mammals hearing. For example, a marine mammal may be able to readily compensate for a brief, relatively small amount of TTS in a non-critical frequency range that occurs during a time where ambient noise is lower and there are not as many competing sounds present. Alternatively, a larger amount and longer duration of TTS sustained during time when communication is critical (

e.g.,

for successful mother/calf interactions, consistent detection of prey) could have more serious impacts.

Currently, TTS data only exist for four species of cetaceans (bottlenose dolphin, beluga whale (

Delphinapterus leucas

), harbor porpoise, and Yangtze finless porpoise (

Neophocaena asiaeorientalis

)) and six species of pinnipeds (northern elephant seal (

Mirounga angustirostris

), harbor seal, ring seal, spotted seal, bearded seal, and California sea lion (

Zalophus californianus

)) that were exposed to a limited number of sound sources (

i.e.,

mostly tones and octave-band noise with limited number of exposure to impulsive sources such as seismic airguns or impact pile driving) in laboratory settings (Southall

et al.,

2019). There is currently no data available on noise-induced hearing loss for mysticetes. For summaries of data on TTS or PTS in marine mammals or for further discussion of TTS or PTS onset thresholds, please see Southall

et al.

(2019) and NMFS (2018).

Recent studies with captive odontocete species (bottlenose dolphin, harbor porpoise, beluga, and false killer whale) have observed increases in hearing threshold levels when individuals received a warning sound prior to exposure to a relatively loud sound (Nachtigall and Supin, 2013, 2015; Nachtigall

et al.,

2016a, 2016b, 2016c; Finneran, 2018; Nachtigall

et al.,

2018). These studies suggest that captive animals have a mechanism to reduce hearing sensitivity prior to impending loud sounds. Hearing change was observed to be frequency dependent and Finneran (2018) suggests hearing attenuation occurs within the cochlea or auditory nerve. Based on these observations on captive odontocetes, the authors suggest that wild animals may have a mechanism to self-mitigate the impacts of noise exposure by dampening their hearing during prolonged exposures of loud sound or if conditioned to anticipate intense sounds (Finneran, 2018, Nachtigall

et al.,

2018).

Behavioral Effects

Exposure of marine mammals to sound sources can result in, but is not limited to, no response or any of the following observable responses: increased alertness; orientation or attraction to a sound source; vocal modifications; cessation of feeding; cessation of social interaction; alteration of movement or diving behavior; habitat abandonment (temporary or permanent);

and in severe cases, panic, flight, stampede, or stranding, potentially resulting in death (Southall

et al.,

2007). A review of marine mammal responses to anthropogenic sound was first conducted by Richardson (1995). More recent reviews address studies conducted since 1995 and focused on observations where the received sound level of the exposed marine mammal(s) was known or could be estimated (Nowacek

et al.,

2007; DeRuiter

et al.,

2012 and 2013; Ellison

et al.,

2012; Gomez

et al.,

2016). Gomez

et al.

(2016) conducted a review of the literature considering the contextual information of exposure in addition to received level and found that higher received levels were not always associated with more severe behavioral responses and vice versa. Southall

et al.

(2021) states that results demonstrate that some individuals of different species display clear yet varied responses, some of which have negative implications while others appear to tolerate high levels and that responses may not be fully predictable with simple acoustic exposure metrics (

e.g.,

received sound level). Rather, the authors state that differences among species and individuals along with contextual aspects of exposure (

e.g.,

behavioral state) appear to affect response probability. Behavioral responses to sound are highly variable and context-specific. Many different variables can influence an animal's perception of and response to (nature and magnitude) an acoustic event. An animal's prior experience with a sound or sound source affects whether it is less likely (habituation) or more likely (sensitization) to respond to certain sounds in the future (animals can also be innately predisposed to respond to certain sounds in certain ways) (Southall

et al.,

2019). Related to the sound itself, the perceived nearness of the sound, bearing of the sound (approaching vs. retreating), the similarity of a sound to biologically relevant sounds in the animal's environment (

i.e.,

calls of predators, prey, or conspecifics), and familiarity of the sound may affect the way an animal responds to the sound (Southall

et al.,

2007, DeRuiter

et al.,

2013). Individuals (of different age, gender, reproductive status,

etc.

) among most populations will have variable hearing capabilities, and differing behavioral sensitivities to sounds that will be affected by prior conditioning, experience, and current activities of those individuals. Often, specific acoustic features of the sound and contextual variables (

i.e.,

proximity, duration, or recurrence of the sound or the current behavior that the marine mammal is engaged in or its prior experience), as well as entirely separate factors such as the physical presence of a nearby vessel, may be more relevant to the animal's response than the received level alone. Overall, the variability of responses to acoustic stimuli depends on the species receiving the sound, the sound source, and the social, behavioral, or environmental contexts of exposure (

e.g.,

DeRuiter

et al.,

2012). For example, Goldbogen

et al.

(2013) demonstrated that individual behavioral state was critically important in determining response of blue whales to sonar, noting that some individuals engaged in deep (greater than 50 m) feeding behavior had greater dive responses than those in shallow feeding or non-feeding conditions. Some blue whales in the Goldbogen

et al.

(2013) study that were engaged in shallow feeding behavior demonstrated no clear changes in diving or movement even when received levels were high (~160 dB re 1µPa) for exposures to 3-4 kHz sonar signals, while deep feeding and non-feeding whales showed a clear response at exposures at lower received levels of sonar and pseudorandom noise. Southall

et al.

(2011) found that blue whales had a different response to sonar exposure depending on behavioral state, more pronounced when deep feeding/travel modes than when engaged in surface feeding.

With respect to distance influencing disturbance, DeRuiter

et al.

(2013) examined behavioral responses of Cuvier's beaked whales to mid-frequency sonar and found that whales responded strongly at low received levels (89-127 dB re 1µPa) by ceasing normal fluking and echolocation, swimming rapidly away, and extending both dive duration and subsequent non-foraging intervals when the sound source was 3.4-9.5 km away. Importantly, this study also showed that whales exposed to a similar range of received levels (78-106 dB

re 1µPa

) from distant sonar exercises (118 km away) did not elicit such responses, suggesting that context may moderate reactions. Thus, distance from the source is an important variable in influencing the type and degree of behavioral response and this variable is independent of the effect of received levels (

e.g.,

DeRuiter

et al.,

2013; Dunlop

et al.,

2017a, 2017b; Falcone

et al.,

2017; Dunlop

et al.,

2018; Southall

et al.,

2019).

Ellison

et al.

(2012) outlined an approach to assessing the effects of sound on marine mammals that incorporates contextual-based factors. The authors recommend considering not just the received level of sound but also the activity the animal is engaged in at the time the sound is received, the nature and novelty of the sound (

i.e.,

is this a new sound from the animal's perspective), and the distance between the sound source and the animal. They submit that this “exposure context,” as described, greatly influences the type of behavioral response exhibited by the animal. Forney

et al.

(2017) also point out that an apparent lack of response (

e.g.,

no displacement or avoidance of a sound source) may not necessarily mean there is no cost to the individual or population, as some resources or habitats may be of such high value that animals may choose to stay, even when experiencing stress or hearing loss. Forney

et al.

(2017) recommend considering both the costs of remaining in an area of noise exposure such as TTS, PTS, or masking, which could lead to an increased risk of predation or other threats or a decreased capability to forage, and the costs of displacement, including potential increased risk of vessel strike, increased risks of predation or competition for resources, or decreased habitat suitable for foraging, resting, or socializing. This sort of contextual information is challenging to predict with accuracy for ongoing activities that occur over large spatial and temporal expanses. However, distance is one contextual factor for which data exist to quantitatively inform a take estimate, and the method for predicting Level B harassment in this rule does consider distance to the source. Other factors are often considered qualitatively in the analysis of the likely consequences of sound exposure where supporting information is available.

Behavioral change, such as disturbance manifesting in lost foraging time, in response to anthropogenic activities is often assumed to indicate a biologically significant effect on a population of concern. However, individuals may be able to compensate for some types and degrees of shifts in behavior, preserving their health and thus their vital rates and population dynamics. For example, New

et al.

(2013) developed a model simulating the complex social, spatial, behavioral and motivational interactions of coastal bottlenose dolphins in the Moray Firth, Scotland, to assess the biological significance of increased rate of behavioral disruptions caused by vessel traffic. Despite a modeled scenario in which vessel traffic increased from 70 to 470 vessels a year (a six-fold increase in vessel traffic) in response to the

construction of a proposed offshore renewables' facility, the dolphins' behavioral time budget, spatial distribution, motivations and social structure remained unchanged. Similarly, two bottlenose dolphin populations in Australia were also modeled over 5 years against a number of disturbances (Reed

et al.,

2020) and results indicate that habitat/noise disturbance had little overall impact on population abundances in either location, even in the most extreme impact scenarios modeled.

Friedlaender

et al.

(2016) provided the first integration of direct measures of prey distribution and density variables incorporated into across-individual analyses of behavior responses of blue whales to sonar and demonstrated a fivefold increase in the ability to quantify variability in blue whale diving behavior. These results illustrate that responses evaluated without such measurements for foraging animals may be misleading, which again illustrates the context-dependent nature of the probability of response.

The following subsections provide examples of behavioral responses that give an idea of the variability in behavioral responses that would be expected given the differential sensitivities of marine mammal species to sound, contextual factors, and the wide range of potential acoustic sources to which a marine mammal may be exposed. Behavioral responses that could occur for a given sound exposure should be determined from the literature that is available for each species, or extrapolated from closely related species when no information exists, along with contextual factors.

Avoidance and Displacement

Avoidance is the displacement of an individual from an area or migration path as a result of the presence of a sound or other stressors and is one of the most obvious manifestations of disturbance in marine mammals (Richardson

et al.,

1995). For example, gray whales (E

schrichtius robustus

) and humpback whales are known to change direction—deflecting from customary migratory paths—in order to avoid noise from airgun surveys (Malme

et al.,

1984; Dunlop

et al.,

2018). Avoidance is qualitatively different from the flight response but also differs in the magnitude of the response (

i.e.,

directed movement, rate of travel,

etc.

). Avoidance may be short-term with animals returning to the area once the noise has ceased (

e.g.,

Malme

et al.,

1984; Bowles

et al.,

1994; Goold, 1996; Stone

et al.,

2000; Morton and Symonds, 2002; Gailey

et al.,

2007; Dähne

et al.,

2013; Russel

et al.,

2016). Longer-term displacement is possible, however, which may lead to changes in abundance or distribution patterns of the affected species in the affected reg

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