Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Sunrise Wind Offshore Wind Farm Project Offshore New York
Federal RegisterFeb 10, 2023
Ask Donna
What actually matters in this document.
Text
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
50 CFR Part 217
[Docket No. 230201-0034]
RIN 0648-BL67
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Sunrise Wind Offshore Wind Farm Project Offshore New York
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 Sunrise Wind, LLC (Sunrise Wind), a 50/50 joint venture between Ørsted North America, Inc. (Ørsted) and Eversource Investment, LLC, for Incidental Take Regulations (ITR) and an associated Letter of Authorization (LOA) pursuant to the Marine Mammal Protection Act (MMPA). The requested regulations would govern the authorization of take, by Level A harassment and/or Level B harassment, of small numbers of marine mammals over the course of 5 years (2023-2028) incidental to construction of the Sunrise Wind Offshore Wind Farm Project offshore of New York in a designated lease area on the Outer Continental Shelf (OCS-A-0487). Project activities likely to result in incidental take include pile driving (impact and vibratory), potential unexploded ordnance or munitions and explosives of concern (UXO/MEC) detonation, and vessel-based site assessment surveys using high-resolution geophysical (HRG) equipment. NMFS requests comments on this proposed rule. NMFS will consider public comments prior to making any final decision on the promulgation of the requested ITR and issuance of the LOA; agency responses to public comments will be summarized in the final rule, if issued. The proposed regulations, if adopted, would be effective November 20, 2023-November 19, 2028.
DATES:
Comments and information must be received no later than March 13, 2023.
ADDRESSES:
Submit all electronic public comments via the Federal e-Rulemaking Portal. Go to
www.regulations.gov
and enter NOAA-NMFS-2023-0012 in the Search box. Click on the “Comment” icon, complete the required fields, and enter or attach your comments.
Instructions:
Comments sent by any other method, to any other address or individual, or received after the end of the comment period, may not be considered by NMFS. All comments received are a part of the public record and will generally be posted for public viewing on
www.regulations.gov
without change. All personal identifying information (
e.g.,
name, address), confidential business information, or otherwise sensitive information submitted voluntarily by the sender will be publicly accessible. NMFS will accept anonymous comments (enter “N/A” in the required fields if you wish to remain anonymous). Attachments to electronic comments will be accepted in Microsoft Word, Excel, or Adobe PDF file formats only.
FOR FURTHER INFORMATION CONTACT:
Jaclyn Daly, Office of Protected Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Availability
A copy of Sunrise Wind's 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 adopted, 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 Sunrise Wind Offshore Wind Farm Project within the Bureau of Ocean Energy Management (BOEM) Renewable Energy Lease Area OCS-A 0487 and along an export cable corridor to a landfall location in New York. NMFS received a request from Sunrise Wind for 5-year regulations and an LOA that would authorize take of individuals of 16 species of marine mammals by harassment only (four species by Level A harassment and Level B harassment and 12 species by Level B harassment) incidental to Sunrise Wind's construction activities. No mortality or serious injury is anticipated or proposed for authorization. Please see the
Estimated Take of Marine Mammals
section below for definitions of harassment.
Legal Authority for the Proposed Action
The MMPA prohibits the “take” of marine mammals, with certain exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.
) direct the Secretary of Commerce (as delegated to NMFS) to allow, upon request, the incidental, but not intentional, taking of small numbers of marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) within a specified geographical region if certain findings are made, regulations are promulgated, and public notice and an opportunity for public comment are provided.
Authorization for incidental takings shall be granted if NMFS finds that the taking will have a negligible impact on the species or stock(s) and will not have an unmitigable adverse impact on the availability of the species or stock(s) for taking for subsistence uses (where relevant). Further, NMFS must prescribe the permissible methods of taking and other “means of effecting the least practicable adverse impact” on the affected species or stocks and their habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance, and on the availability of the species or stocks for taking for certain subsistence uses (referred to as “mitigation”); and requirements pertaining to the mitigation, monitoring and reporting of the takings are set forth. The definitions of all applicable MMPA statutory terms cited above are included below.
Section 101(a)(5)(A) of the MMPA and the implementing regulations at 50 CFR part 216, subpart I provide the legal basis for proposing and, if appropriate, issuing 5-year regulations and an associated LOA. This proposed rule also establishes required mitigation, monitoring, and reporting requirements for Sunrise Wind's activities.
Summary of Major Provisions Within the Proposed Rule
The major provisions within this proposed rule are as follows:
• Establishing a seasonal moratorium on impact pile driving during the months of highest North Atlantic right whale (
Eubalaena glacialis
) presence in the project area (January 1-April 30);
• Establishing a seasonal moratorium on any UXO/MEC detonations during the months of highest North Atlantic right whale present in the project area (December 1-April 30).
• Requiring that any UXO/MEC detonations may occur only during hours of daylight and not during hours of darkness or night.
• Conducting 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;
• Requiring the use of sound attenuation device(s) during all impact pile driving and UXO/MEC detonations to reduce noise levels;
• Delaying 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 vessels;
• Delaying the start of pile driving if other marine mammals are observed entering or within their respective clearance zones;
• Shutting down pile driving (if feasible) if a North Atlantic right whale is observed or if other marine mammals enter their respective shut down zones;
• Implementing soft-starts for impact pile driving and using the least hammer energy possible;
• A requirement to implement noise abatement system(s) during all impact pile driving and UXO/MEC detonations;
• Implementing ramp-up for HRG site characterization survey equipment;
• Requiring PSOs to continue to monitor for 30 minutes after any impact pile driving occurs and for any and after all UXO/MEC detonations;
• Increasing awareness of North Atlantic right whale presence through monitoring of the appropriate networks and Channel 16 as well as reporting any sightings to the sighting network;
• Implementing vessel strike avoidance measures;
• Sound field verification requirements during impact pile driving and UXO/MEC detonation to measure
in situ
noise levels for comparison against the model results; and
• Implementing best management practices during fisheries monitoring surveys such as removing gear from the water if marine mammals are considered at-risk or are interacting with gear.
Under Section 105(a)(1) of the MMPA, failure to comply with these requirements or any other requirements in a regulation or permit implementing the MMPA may result in civil monetary penalties. Pursuant to 50 CFR 216.106, violations may also result in suspension or withdrawal of the Letter of Authorization (LOA) for the project. Knowing violations may result in criminal penalties under Section 105(b) of the MMPA.
National Environmental Policy Act (NEPA)
To comply with the National Environmental Policy Act of 1969 (NEPA; 42 U.S.C. 4321
et seq.
) and NOAA Administrative Order (NAO) 216-6A, NMFS must evaluate the proposed action (
i.e.,
promulgation of regulations and subsequent issuance of a 5-year LOA) and alternatives with respect to potential impacts on the human environment.
Accordingly, NMFS proposes to adopt BOEM's Environmental Impact Statement (EIS), provided our independent evaluation of the document finds that it includes adequate information analyzing the effects of promulgating the proposed regulations and LOA issuance on the human environment. NMFS is a cooperating agency on BOEM's EIS. BOEM's draft EIS (Sunrise Wind Draft Environmental Impact Statement (DEIS) for Commercial Wind Lease OCS-A 0487) was made available for public comment on December 16, 2022 (87 FR 77136), beginning the 60-day comment period ending on February 14, 2023. Additionally, BOEM held three virtual public hearings on January 18, January 19, and January 23, 2023.
Information contained within Sunrise Wind's incidental take authorization (ITA) application and this proposed rule 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 the NEPA process or making a final decision on the requested 5-year ITR and LOA.
Fixing America's Surface Transportation Act (FAST-41)
This project is covered under Title 41 of the Fixing America's Surface Transportation Act, or “FAST-41.” FAST-41 includes a suite of provisions designed to expedite the environmental review for covered infrastructure projects, including enhanced interagency coordination as well as milestone tracking on the public-facing Permitting Dashboard. FAST-41 also places a 2-year limitations period on any judicial claim that challenges the validity of a Federal agency decision to issue or deny an authorization for a FAST-41 covered project. 42 U.S.C. 4370m-6(a)(1)(A).
Sunrise Wind's proposed project is listed on the Permitting Dashboard, where milestones and schedules related to the environmental review and permitting for the project can be found:
https://www.permits.performance.gov/permitting-project/sunrise-wind-farm.
Summary of Request
On November 10, 2021, Sunrise Wind submitted a request for the promulgation of regulations and issuance of an associated 5-year LOA to take marine mammals incidental to construction activities associated with implementation of the Sunrise Wind Offshore Wind Farm Project (herein “SWF”) offshore of New York in the BOEM Lease Area OCS-A-0487. Sunrise Wind's request is for the incidental, but not intentional, taking of a small number of 16 marine mammal species (comprising 16 stocks) by Level B harassment (for all 16 species or stocks) and by Level A harassment (for 4 species or stocks). Neither Sunrise Wind nor NMFS expects serious injury or mortality to result from the specified activities nor is any proposed for authorization.
In response to our questions and comments and following extensive information exchange between Sunrise Wind and NMFS, Sunrise Wind submitted a final revised application on May 9, 2022, which NMFS deemed adequate and complete on May 10, 2022. This final application is available on NMFS' website at:
https://www.fisheries.noaa.gov/action/incidental-take-authorization-sunrise-wind-llc-construction-and-operation-sunrise-wind.
On June 2, 2022, NMFS published a notice of receipt (NOR) of Sunrise Wind's adequate and complete application in the
Federal Register
(87 FR 33470), requesting comments and soliciting information related to Sunrise Wind's request during a 30-day public comment period. During the NOR public comment period, NMFS received comment letters from two environmental non-governmental organizations: Clean Ocean Action and Oceana. NMFS has reviewed all submitted material and has taken the material into consideration during the drafting of this proposed rule. Subsequently, in June 2022, new scientific information was released regarding marine mammal densities (Robert and Halpin, 2022) and, as such, Sunrise Wind submitted a final Updated Density and Take Estimation Memo to NMFS on December 15, 2022 that included updated marine mammal densities and take estimates. This memo is available on our website at
https://www.fisheries.noaa.gov/action/incidental-take-authorization-sunrise-wind-llc-construction-and-operation-sunrise-wind
).
NMFS previously issued four Incidental Harassment Authorizations (IHAs) to Ørsted for the taking of marine mammals incidental to marine site characterization surveys (using HRG equipment) of the Sunrise Wind's BOEM Lease Area (OCS-A 0487) and
surrounding BOEM Lease Areas (OCS-A 0486, OCS-A 0500) (see 84 FR 52464, October 2, 2019; 85 FR 63508, October 8 14, 2020; 87 FR 756, January 6, 2022; and 87 FR 61575, October 12, 2022). To date, Ørsted has complied with all IHA requirements (
e.g.,
mitigation, monitoring, and reporting). Information regarding Ørsted's monitoring results may be found in the Estimated Take of Marine Mammals section, and the full monitoring reports can be found on NMFS' website:
https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable.
On August 1, 2022, NMFS announced proposed changes to the existing North Atlantic right whale vessel speed regulations to further reduce the likelihood of mortalities and serious injuries to endangered North Atlantic right whales from vessel collisions, which are a leading cause of the species' decline and a primary factor in an ongoing Unusual Mortality Event (87 FR 46921). Should a final vessel speed rule be 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 of the effective date, NMFS would also notify Sunrise Wind if the measures in the speed rule were to supersede any of the measures in the MMPA authorization such that they were no longer required.
Description of the Specified Activity
Overview
Sunrise Wind has proposed to construct and operate a 924 to 1,034 megawatt (MW) wind energy facility (known as Sunrise Wind Farm (SRWF)) in state and Federal waters in the Atlantic Ocean in lease area OCS-A-0487, located within the Massachusetts and Rhode Island Wind Energy Area (RI/MA WEA). Sunrise Wind's project would consist of several different types of permanent offshore infrastructure, including wind turbine generators (WTGs) and associated foundations, an offshore converter substation (OCS-DC), offshore substation array cables, and substation interconnector cables. Specifically, activities to construct the project include the installation of up to 94 WTGs (at 102 potential locations) and 1 OCS-DC via impact pile driving; impact and vibratory pile driving at the cable landfall site; trenching, laying, and burial activities associated with the installation of the export cable route from the OCS-DC to the shore-based converter station and inter-array cables between turbines; site preparation work (
e.g.,
boulder removal); placement of scour protection around foundations; HRG vessel-based site characterization surveys using active acoustic sources with frequencies of less than 180 kHz; detonating up to three UXO/MEC of different charge weights; and several types of fishery and ecological monitoring surveys. Vessels would transit within the project area and between ports and the wind farm to transport crew, supplies, and materials to support pile installation. All offshore cables will connect to onshore export cables, substations, and grid connections, which would be located on Long Island. Marine mammals exposed to elevated noise levels during impact and vibratory pile driving, detonations of UXOs, or site characterization surveys may be taken by Level A harassment and/or Level B harassment depending on the specified activity.
Dates and Duration
Sunrise Wind anticipates that activities with the potential to result in harassment of marine mammals would occur throughout all 5 years of the proposed regulations which, if promulgated, would be effective from November 20, 2023 through November 19, 2028.
The estimated schedule, including dates and duration, for various activities is provided in Table 1 (also see Table 4 and Figure 6 in Sunrise Wind's application); however, this proposed rule considers the potential for activity schedules to shift. Detailed information about the activities themselves may be found in the
Detailed Description of Specific Activity
subsection.
Table 1—Estimated Activity Schedule To Construct and Operate the Sunrise Wind Project
Project area
Project activity
Expected timing and duration
Sunrise Wind Farm (SRWF) Construction
WTG Foundation Installation
Q3-Q4 2024; 4-5 months.
OCS-DC Foundation Installation
Q4 2024; 2-3 days (48-72 hours).
WTG Installation
Q4 2024-Q2 2025; 9 months.
Seafloor preparation
Q1-Q2 2024
Array Cable Installation
Q2-Q3 2025; 7 months.
UXO/MEC detonation
Q2 2024; 3 days.
Sunrise Wind Export Corridor (SRWEC) Construction
Cable Landfall Installation (casing pipe and sheetpile installation and removal,
HDD
)
Q4 2023-Q1 2024; 16 days.
Offshore Export Cable Installation
Route clearance
Q2 2024
EC Installation
Q4 2024 to Q1 2025; 8 months.
HRG Survey
Q4 2023-Q4 2025; Any time of year.
Operations
HRG Survey
Q4 2024-Q3 2028; Any time of year.
Italicized activities do not have the potential to result in take of marine mammals.
WTG and OCS-DC Foundation Installation
The installation of 94 WTG and 1 OCS-DC foundations would be limited to May through December, given the seasonal restriction on foundation impact pile driving from January 1-April 30. As described previously, Sunrise Wind intends to install all foundations in a single year over the course of 4 to 5 months. However, it is possible that monopile installation would continue into a second year depending on construction logistics and local and environmental conditions that may influence Sunrise Wind's ability to maintain the planned construction schedule.
Installation of a single monopile foundation is expected to require a maximum of 4 hours of active impact hammering, which can occur either in a continuous 4-hour interval or intermittently over a longer time period. Installation of a single piled jacket foundation is estimated to require approximately 48 hours of pile driving per jacket (which includes up to 6 hours of pile driving per pile). It is assumed that the pile driving would occur within a 72-hour window (~ 3 days) including wait time in between pile installation. Pile driving activity will include a 20-minute soft-start at the beginning of each pile installation.
Sunrise Wind has provided five scenarios for how many piles may be installed on a given day. Piles may be installed consecutively (one at a time) or concurrently (multiple piles at the same time). Potential daily pile driving scenarios include:
• Consecutive installation of two WTG monopiles or four OCS-DC pin piles consecutively in 1 day for 53 days;
• Consecutive installation of three WTG monopiles or four OCS-DC pin piles consecutively in 1 day for 36 days;
• Concurrent installation of four WTG monopiles in 1 day, two each by two different installation vessels operating concurrently in close proximity to each other (“Proximal”,
i.e.
3 nautical miles apart) for 25.5 days, plus 4 OCS-DC pin piles per day for 2 days;
• Concurrent installation of four WTG monopiles in 1 day, two each by two different installation vessels operating concurrently at long distances from each other (“Distal”,
i.e.
opposite ends of the SRWF) for 25.5 days plus four OCS-DC pin piles per day for 2 days; or
• Concurrent installation of two WTG monopiles by one vessel and four OCS-DC pin piles by a second vessel for 2 days followed by two WTG monopiles per day by a single vessel for 49 days.
Sunrise Wind anticipates that the first WTGs would become operational in Q3 2025 after installation is completed and all necessary components, such as array cables, OCS-DC, export cable routes, and onshore substations are installed. Turbines would be commissioned individually by personnel on location, so the number of commissioning teams would dictate how quickly turbines would become operational. Sunrise Wind expects that all turbines will be commissioned by Q4 2025.
UXO/MEC Detonations
Based on preliminary survey data, Sunrise Wind estimates a maximum of 3 days of UXO/MEC detonation may occur with up to one UXO/MEC being detonated per day. Any UXO/MEC detonation would occur during daylight hours only after proper marine mammal monitoring is conducted (see Proposed Monitoring and Reporting section). Sunrise Wind anticipates UXO/MEC detonation would be limited to Q2 2024. Sunrise Wind would not detonate UXOs/MECs between December and April.
Cable Landfall Construction
Cable landfall construction is one of the first activities scheduled to occur, sometime between Q4 2023-Q1 2024. In their application, Sunrise Wind indicated they would install and remove up to two casing pipes and supporting goal posts over 36 days; however, the project has been refined such that only one casing pipe and goal posts would be installed and removed over 16 days. Installation of the single casing pipe may take up to 3 hours of pneumatic hammering on each of 2 days for installation. Removal of the casing pipe is anticipated to require approximately the same amount of pneumatic hammering and overall time, or less, meaning the pneumatic pipe ramming tool may be used for up to 3 hours per day over 4 days. Up to 22 sheet piles may be installed to support the work. Sheet pile may require up to 2 hours of vibratory piling and up to 4 sheet piles may be installed per day (total of 8 hours of vibratory pile driving per day). Removal of the goal posts may also involve the use of a vibratory hammer and likely require approximately the same amount of time as installation (6 days total). Thus, use of a vibratory pile driver to install and remove sheet piles may occur on up to 12 days at the landfall location.
HRG Surveys
High-resolution geophysical site characterization surveys would occur annually throughout the 5 years the rule and LOA would be effective with duration dependent on the activities occurring in that year (
i.e.,
construction versus non-construction year). HRG surveys would utilize up to a maximum of four vessels working concurrently in different sections of the Lease Area and SRWEC corridor. During the first year of construction (when the majority of foundations and cables are installed), Sunrise Wind estimates that a total of 12,275 km may be surveyed over 175 vessel days within the Lease Area and along the SRWEC corridor in water depths ranging from 2 m (6.5 ft) to 55 m (180 ft). During non-construction years (Yrs 3-5), Sunrise Wind estimates 6,311.2 km would be surveyed over 90.2 vessel days per year. Each day that a survey vessel covers 70 km (44 miles) of survey trackline is considered vessel day. For example, Sunrise Wind would consider two vessels operating concurrently, with each surveying 70 km (44 miles), two vessel days. Sunrise Wind anticipates that each vessel would survey an average of 70 km (44 miles) per day, assuming a 4 km/hour (2.16 knots) vessel speed and 24-hour operations. In some cases, vessels may conduct daylight-only 12-hour nearshore surveys covering half that distance (35 km or 22 miles). Over the course of 5 years, HRG surveys would be conducted at any time of year for a total of 48,484 km over 622 vessel days. In this schedule, Sunrise Wind accounted for periods of down-time due to inclement weather or technical malfunctions.
Specific Geographic Region
Sunrise Wind would construct the SRWF in Federal waters offshore of New York (Figure 1). The lease area OCS-A 0487 is part of the Rhode Island/Massachusetts Wind Energy Area (RI-MA WEA). The Lease Area covers approximately 86,823 acres (351 km
2
) and is located approximately 18.9 statute miles (mi) (16.4 nautical miles (nmi), 30.4 kilometers (km)) south of Martha's Vineyard, Massachusetts; approximately 30.5 mi (26.5 nmi, 48.1 km) east of Montauk, New York; and 16.7 mi (14.5 nmi, 26.8 km) from Block Island, Rhode Island Water depths in the Lease Area range from 35 to 62 m (115-203 ft), averaging 49 m (160.8 ft), while water depths along the SRWEC corridor range from 5.7 to 67 m (18.7 to 219.8 ft). The cable landfall construction area would be approximately 5.7 m (18.7 ft) in depth. Cables would come ashore at the Smith Point County Park.
Sunrise Wind's specified activities would occur in the Northeast U.S. Continental Shelf Large Marine Ecosystem (NES LME), an area of approximately 260,000 km
2
from Cape Hatteras in the south to the Gulf of
Maine in the north. Specifically, the lease area and cable corridor are located within the Mid-Atlantic Bight subarea of the NES LME, which extends between Cape Hatteras, North Carolina, and Martha's Vineyard, Massachusetts, extending westward into the Atlantic to the 100-m isobath. In the Mid-Atlantic Bight, which extends from Massachusetts to North Carolina,the pattern of sediment distribution is relatively simple. The continental shelf south of New England is broad and flat, dominated by fine grained sediments. Most of the surficial sediments on the continental shelf are sands and gravels. Silts and clays predominate at and beyond the shelf edge, with most of the slope being 70-100 percent mud. Fine sediments are also common in the shelf valleys leading to the submarine canyons, as well as in areas such as the “Mud Patch” south of Rhode Island. There are some larger materials, including boulders and rocks, left on the seabed by retreating glaciers, along the coast of Long Island and to the north and east.
In support of the Rhode Island Ocean Special Area Management Plan development process, Codiga and Ullman (2011) reviewed and summarized the physical oceanography of coastal waters off Rhode Island. Conditions off the coast of Rhode Island are shaped by a complex interplay among wind-driven variability, tidal processes, and density gradients that arise from combined effects of interaction with adjacent estuaries, solar heating, and heat flux through the air-sea interface. In winter and fall, the stratification is minimal and circulation is a weak upwelling pattern directed offshore at shallow depths and onshore near the seafloor. In spring and summer strong stratification develops due to an important temperature contribution, and a system of more distinct currents occurs, including a narrow flow that proceeds counterclockwise around the perimeter of RIS likely in association with a tidal mixing front.
The waters in the vicinity of the SRWF and SRWEC are transitional waters positioned between the continental slope and the coastal environments of Long Island Sound and Narragansett Bay. The region is generally characterized by predominantly mobile sandy substrate, and the associated benthic communities are adopted to survive in a dynamic environment. The WEAs are composed of a mix of soft and hard bottom environments as defined by the dominant sediment grain size and composition (Continental Margin Mapping Program [Department of the Interior 2020]; usSEABED [USGS 2020]. The benthic environment of the RI-MA WEA is dominated by sandy sediments that ranged from very fine to medium sand; very fine sands tend to be more prevalent in deeper, lower energy areas (
i.e.,
the southern portion of the MA WEA), whereas coarser sediments, including gravels (
e.g.,
patchy cobbles and boulders) were found in shallower areas (Bay State Wind 2019, Deepwater Wind South Fork, LLC 2019; DWW Rev I, LLC 2020; Stokesbury 2014; LaFrance
et al.
2010; McMaster 1960; Popper
et al.
2014). The species that inhabit the benthic habitats of the OCS are typically described as infaunal species, those living in the sediments (
e.g.,
polychaetes, amphipods, mollusks), and epifaunal species, those living on the seafloor surface (mobile,
e.g.,
sea starts, sand dollars, sand shrimp) or attached to substrates (sessile,
e.g.,
barnacles, anemones, tunicates). Further detail on the benthic habitats found at the SRWF and along the SRWEC, including the results of site-specific benthic habitat assessments, can be found within COP section 4.4.2, COP Appendices M1—Benthic Resources Characterization Report—Federal Waters, M2—Benthic Resources Characterization Report—New York State Waters, and M3—Benthic Habitat Mapping Report.
EP10FE23.000
Detailed Description of Specific Activity
Below, we provide detailed descriptions of Sunrise Wind's activities, explicitly noting those that are anticipated to result in the take of marine mammals and for which incidental take authorization is requested. Additionally, a brief explanation is provided for those activities that are not expected to result in the take of marine mammals.
Installation of WTG Foundations
Sunrise Wind plans to install up to 94 WTG monopile foundations with a maximum diameter tapering from 7 m above the waterline to 12 m (39 ft) below the waterline (7/12 m monopile (see Figure 3 in Sunrise Wind's application)) in lease area OCS-0487 spaced in a 1 nmi x 1 nmi grid pattern. The Project will generate between 924 to 1,034 MW of renewable energy. Although up to 94 WTGs are expected to be installed, Sunrise Wind has accounted for up to 8 potential locations where WTG installation is begun but unable to be completed due to environmental or engineering constraints (
i.e.,
only 94 WTGs will be installed but within 102 potential locations).
Figure 3 in Sunrise Wind's application provides a conceptual example of the WTG support structures (
i.e.,
towers and foundations), which will be designed to withstand 500-year hurricane wind and wave conditions, and the external platform level will be designed above the 1,000-year wave scenario. A WTG monopile foundation typically consists of a single steel tubular section with several sections of rolled steel plate welded together. Secondary structures on each WTG monopile foundation will include a boat landing or alternative means of safe access (
e.g.,
Get Up Safe—a motion compensated hoist system allowing vessel to foundation personnel transfers without a boat landing), ladders, a crane, and other ancillary components.
A typical monopile installation sequence begins with the monopiles transported directly to the Sunrise Wind Farm for installation or to the construction staging port by an installation vessel or a feeding barge. At the foundation location, the main installation vessel upends the monopile in a vertical position in the pile gripper mounted on the side of the vessel. The hammer is then lifted on top of the pile and pile driving commences with a soft-start and proceeds to completion. Piles are driven until the target embedment depth is met (up to 50 m), then the pile hammer is removed and the monopile is released from the pile gripper. Once installation of the monopile is complete, the vessel moves to the next installation location.
Monopiles would be installed using a 4,000 kJ impact pile driver (although, in general, only up to 3,200 kJ will be necessary except for potentially 1 strike at 4,000 kJ) to a maximum penetration depth of 50 m (164 ft). Installation of each monopile will include a 20-minute soft-start where lower hammer energy is used at the beginning of each pile installation. Under normal conditions, after completion of the 20-minute soft-start period, installation of a single monopile foundation is estimated to require 1-4 hours of active pile driving; however, breaks may be necessary such that 1-4 hours of pile driving occurs over several more hours (up to 12 hours). Sunrise Wind anticipates it would then take approximately 4 hours to move to the next piling location. Once at the new location, a 1-hour monitoring period would occur such that there would be no less than 5 hours between each pile installation. In total,
376 hours (94 WTGs × 4 hours each) would be the maximum amount of time impact monopile driving would occur over the course of 1 year. Sunrise Wind is proposing to install foundations consecutively or concurrently (see Dates and Duration section). Impact pile driving associated with WTG foundation installation would be limited to the months of May through December and is currently scheduled to be conducted during Q3 and Q4 2024. Installation of WTG foundations is anticipated to result in the take of marine mammals due to noise generated during pile driving.
Sunrise Wind has proposed to conduct pile driving 24-hours per day. Once construction begins, Sunrise Wind would proceed as rapidly as possible, while meeting all required mitigation and monitoring measures, to reduce the total duration of construction. Orsted, the parent company of Sunrise Wind, is currently analyzing data from pilot projects investigating the efficacy of technology to monitor (visually and acoustically) marine mammals during nighttime and reduced visibility conditions. NMFS acknowledges the benefits of completing construction quickly during times when North Atlantic right whales are unlikely to be in the area but also recognizes challenges associated with monitoring during reduced visibility conditions such as night. Should Sunrise Wind submit a NMFS-approved Alternative Monitoring Plan, pile driving may be initiated at night. NMFS intends to condition the final rule, if issued, identifying if initiating pile driving at night may occur.
Offshore Converter Station (OCS-DC)
Sunrise Wind would install a single OCS-DC for the project on a jacket foundation (see Figure 4 in Sunrise Wind's application). A piled jacket foundation is formed of 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. The piled jacket foundation will have four legs with two pin piles per leg (eight piles total). The platform height will be up to 26.8 m (88 ft) with a leg diameter of up to 4.6 m (15 ft) and a pile diameter of up to 4 m (13 ft). Installation of OCS-DC jacket foundation pin piles (two per leg, eight total) will be performed using an impact pile driver with a maximum hammer energy of 4,000-kJ to a maximum penetration depth of 90 m (295 ft). It is assumed that installation of the jacket foundation would require 48 hours of pile driving total (6 hours per pile), which would occur over 3 days. The current schedule estimates the OCS-DC jacket foundation would be installed in Q4 2024. Installation of the OCS-DC jacket foundation is anticipated to result in the take of marine mammals due to noise generated during pile driving.
The OCS-DC requires the withdrawal of raw seawater through a cooling water intake structure (CWIS) to dissipate heat produced through the AC to DC conversion and then discharge this water as thermal effluent to the marine receiving waters. It includes intake pipes and sweater lift pumps (SWLP), course filters, electrochlorination system, heat exchange system, and a dump caisson. The OCS-DC would discharge non-contact cooling water (NCCW) and non-contact stormwater to the marine receiving waters. The design intake flow (DIF) for the OCS-DC is 8.1 million gallons per day (MGD); however, the Average Flow Intake (AFI) will generally range from 4.0 MGD to 5.3 MGD. The rate at which seawater would be taken (
e.g.
maximum through-screen velocity [TSV]) is 0.1525 m/s [0.5 ft/s]). The dump caisson consists of a single outlet vertical pipe oriented downward in the water column. The dump caisson is the primary discharge point for the OCS-DC. Pollutants discharged at the dump caisson will include NCCW and residual chlorine. The temperature of the water exiting the heat exchange system will depend on the ambient air temperature, ambient water temperature, power output, and other factors. Sunrise Wind indicated the maximum temperature under all operating scenarios and conditions will not exceed 32 °C (90 °F) and the thermal plume is not expected to extend beyond 30 m of the dump caisson. No take of marine mammals would occur due to water withdrawal or thermal discharge.
Cable Landfall Construction
Installation of the SRWF export cable landfall will be accomplished using a horizontal directional drilling (HDD) methodology. HDD will be used to connect the SRWEC offshore cable to the Onshore Transmission Cable at the landfall location and to cross the Intercoastal Waterway (ICW) from Fire Island to mainland Long Island. The drilling equipment will be located onshore and used to create a borehole, one for each cable, from shore to an exit point on the seafloor approximately 0.5 mi (800 m) offshore. At the seaward exit site for each borehole, construction activities may include the temporary installation of a casing pipe, supported by sheet pile goal posts, to collect drilling mud from the borehole exit point. Additionally, 10 sheet piles may be used to support the casing pipe and help to anchor/stabilize the vessel which will be collecting drilling fluid. Installation of up to two casing pipes (one at each HDD exit pit location) would be completed using pneumatic pipe ramming equipment while installation of sheet pile for goal posts would be completed using a vibratory pile driving hammer. These activities would not occur simultaneously as some of the same equipment on the barge is necessary to conduct both types of installations. All installation activities would occur during daylight periods.
Sunrise Wind would install a single casing pipe at an 11-12-degree angle with the seabed so that the casing pipe creates a straight alignment between the point of penetration at the seabed and the construction barge. Casing pipe installation will occur from the construction barge and be accomplished using a pneumatic pipe ramming tool (
e.g.,
Grundoram Taurus or similar) with a hammer energy of up to 18 kJ. If necessary, additional sections of casing pipe may be welded together on the barge to extend the length of the casing pipe from the barge to the penetration depth in the seabed.
Installation of the single casing pipe may take up to 3 hours of pneumatic hammering on each of the 2 days for installation. Installation time will be dependent on the number of pauses required to weld additional sections onto the casing pipe. Removal of the casing pipe is anticipated to require approximately the same amount of pneumatic hammering and overall time, or less, meaning the pneumatic pipe ramming tool may be used for up to 3 hours per day on up to 4 days.
Up to six goal posts may be installed to support the casing pipe between the barge and the penetration point on the seabed. Each goal post would be composed of two vertical sheet piles installed using a vibratory hammer such as an American Pile Equipment (APE) model 300 (or similar). A horizontal cross beam connecting the two sheet piles would then be installed to provide support to the casing pipe. Up to 10 additional sheet piles may be installed to help anchor the barge and support the construction activities. This results in a total of up to 22 sheet piles. Installation of the goal posts would require up to 6 days. Sheet pile may require up to 2 hours of vibratory piling and up to four sheet piles may be installed per day (total of 8 hours of vibratory pile driving per day). Removal of the goal posts may also involve the use of a vibratory hammer and likely require approximately the same amount of time
as installation (6 days total). Thus, use of a vibratory pile driver to install and remove sheet piles may occur on up to 12 days at the landfall locations. Installation and removal of the casing pipe and goal posts is anticipated to result in the take of marine mammals due to noise generated during pile driving.
UXO/MEC Detonations
Sunrise Wind anticipates the potential for construction activities to encounter UXO/MECs on the seabed within the SRWF and along the SRWEC corridor. UXO/MECs include explosive munitions such as bombs, shells, mines, torpedoes,
etc.,
that did not explode when they were originally deployed or were intentionally discarded in offshore munitions dump sites to avoid land-based detonations. The risk of incidental detonation associated with conducting seabed-altering activities, such as cable laying and foundation installation in proximity to UXO/MECs, jeopardizes the health and safety of project participants (Sunrise Wind 2022). Sunrise Wind follows an industry standard As Low as Reasonably Practicable (ALARP) process that minimizes the number of potential detonations (COP Appendix G2, (Sunrise-Wind 2021).
For UXO/MECs that are positively identified in proximity to planned activities on the seabed, several alternative strategies will be considered prior to in-situ UXO/MEC disposal. These may include (1) relocating the activity away from the UXO/MEC (avoidance), (2) moving the UXO/MEC away from the activity (lift and shift), (3) cutting the UXO/MEC open to apportion large ammunition or deactivate fused munitions, using shaped charges to reduce the net explosive yield of a UXO/MEC (low-order detonation), or (4) using shaped charges to ignite the explosive materials and allow them to burn at a slow rate rather than detonate instantaneously (deflagration). Only after these alternatives are considered would in-situ high-order UXO/MEC detonation be pursued. To detonate a UXO/MEC, a small charge would be placed on the UXO/MEC and ignited, causing the UXO/MEC to then detonate, which could result in the take of marine mammals.
To better assess the likelihood of encountering UXO/MECs during project construction, Sunrise Wind has and will continue to conduct HRG surveys to identify potential UXO/MECs that have not been previously mapped. As these surveys and analysis of data from them are still underway, the exact number and type of UXO/MECs in the project area are not yet known. However, Sunrise Wind assumes that up to three UXO/MEC 454-kg (1000 pounds; lbs) charges, which is the largest charge that is reasonably expected to be encountered, may require
in situ
detonation. Although it is highly unlikely that all three charges would weigh 454 kg, this approach was determined to be the most conservative for the purposes of impact analysis. If necessary, these detonations would occur on up to 3 different days (
i.e.,
only one detonation would occur per day). In the event that high-order removal (detonation) is determined to be the preferred and safest method of disposal, all detonations would occur during daylight hours. Sunrise Wind would avoid detonating UXO/MECs from December 1 through April 30 to provide protection for North Atlantic right whales during the timeframe they are expected to occur more frequently in the project area. UXO/MEC detonation is anticipated to result in the take of marine mammals due to noise.
HRG Surveys
HRG surveys would be conducted to identify any seabed debris and to support micrositing of the WTG and OCS-DC foundations and cable routes. These surveys may utilize active 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), ultra-short baseline positioning equipment, and marine magnetometers, some of which are expected to result in the take of marine mammals. Equipment may be mounted to the survey vessel or Sunrise Wind may use autonomous surface vehicles (SFV) to carry out this work. Surveys would occur annually, with durations dependent on the activities occurring in that year (
i.e.,
construction years versus operational years).
As summarized previously, HRG surveys will be conducted using up to four vessels. On average, 70-line km will be surveyed per vessel each survey day at approximately 7.4 km/hour (4 knots) on a 24-hour basis although some vessels may only operate during daylight hours (~12-hour survey vessels). During the construction phase (Yr1 and Yr2), an estimated 24,550 survey line km, plus in-fill and re-surveys, may be necessary to survey the inter-array cables and the Sunrise Wind Export Cable in water depths ranging from 2 m (6.5 ft) to 55 m (180 ft). HRG surveys are anticipated to operate at any time of year for a maximum of 351 active sound source days over the 2 years of construction. During the operations phase (Yrs 3-5), an estimated 6,311 km per year for 3 years (18,933 km total) may be surveyed in the Sunrise Wind Farm and along the Sunrise Wind Export Cable. Using the same estimate of 70 km of survey completed each day per vessel, approximately 90 days of survey would occur each year for a total of up to 270 active sound source days over the 3-year operations period. In total, across all 5 years, a total of 43,484 kms of trackline may be surveyed.
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 2 identifies all the representative survey equipment that operate below 180 kilohertz (kHz) (
i.e.,
at frequencies that are audible and have the potential to disturb marine mammals) that may be used in support of planned geophysical survey activities and are likely to be detected by marine mammals given the source level, frequency, and beamwidth of the equipment. Equipment with operating frequencies above 180 kHz and equipment that does not have an acoustic output (
e.g.,
magnetometers) will also be used but are not discussed further because they are outside the general hearing range of marine mammals likely to occur in the project area or do not produce noise. Hence, no harassment is reasonably expected to occur from the operation of these sources.
Table 2—Summary of Representative HRG Survey Equipment
Equipment type
Representative model
Operating frequency (kHz)
Source
level SPLrms (dB)
Source level 0-pk (dB)
Pulse
duration
(ms)
Repetition
rate (Hz)
Beamwidth (degrees)
Source
Sub-bottom profiler
EdgeTech 216
2-16
195
-
20
6
24
MAN
EdgeTech 424
4-24
176
-
3.4
2
71
CF
Edgetech 512
0.7-12
179
-
9
8
80
CF
GeoPulse 5430A
2-17
196
-
50
10
55
MAN
Teledyn Benthos CHIRP III—TTV 170
2-17
197
-
60
15
100
MAN
Sparker
Applied Acoustics Dura-Spark UHD (400 tips, 500 J)
0.3-1.2
203
211
1.1
4
Omni
CF
Boomer
Applied Acoustics triple plate S-Boom (700-1,000 J)
0.1-5
205
211
0.6
4
80
CF
- = not applicable; ET = EdgeTech; J = joule; kHz = kilohertz; dB = decibels; SL = source level; UHD = ultra-high definition; AA = Applied Acoustics; rms = root-mean square; µPa = microPascals; re = referenced to; SPL = sound pressure level; PK = zero-to-peak pressure level; Omni = omnidirectional source.
a
The Dura-spark measurements and specifications provided in Crocker and Fratantonio (2016) were used for all sparker systems proposed for the survey. These include variants of the Dura-spark sparker system and various configurations of the GeoMarine Geo-Source sparker system. The data provided in Crocker and Fratantonio (2016) represent the most applicable data for similar sparker systems with comparable operating methods and settings when manufacturer or other reliable measurements are not available.
b
Crocker and Fratantonio (2016) provide S-Boom measurements using two different power sources (CSP-D700 and CSP-N). The CSP-D700 power source was used in the 700 J measurements but not in the 1,000 J measurements. The CSP-N source was measured for both 700 J and 1,000 J operations but resulted in a lower SL; therefore, the single maximum SL value was used for both operational levels of the S-Boom.
Cable Laying and Installation
Cable burial operations would occur both in SRWF for the inter-array cables connecting the 94 WTGs to single OCS-DC and in the SRWEC corridor for cables carrying power from the OCS-DC to shore. The offshore export and inter-array cables would be buried in the seabed at a target depth of up to 1.2 to 2.8 m (4 to 6 ft) and buried onshore up to the transition joint bays. All cable burial operations would follow installation of the monopile foundations as the foundations must be in place to provide connection points for the export cable and inter-array cables. Cable laying, cable installation, and cable burial activities planned to occur during the construction of the Sunrise Wind project may include the following: jetting; vertical injection; leveling; mechanical cutting; plowing (with or without jet-assistance); pre-trenching; boulder removal; and controlled flow excavation.
Some dredging may be required prior to cable laying due to the presence of sandwaves. Sandwave clearance may be undertaken where cable exposure is predicted over the lifetime of the 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. The work could be undertaken by traditional dredging methods such as a trailing suction hopper. Alternatively, controlled flow excavation or a sandwave removal plough could be used. In some cases, multiple passes may be required. The method of sandwave clearance Sunrise Wind chooses would be based on the results from the site investigation surveys and cable design.
As the noise levels generated from cable laying and installation work are low, the potential for take of marine mammals to result is discountable. Sunrise Wind is not requesting, and NMFS is not proposing to authorize, take associated with cable laying activities. Therefore, cable laying activities are not analyzed further in this document.
Temporary Pier Construction
Construction of the cable landfall at Smith Point County Park parking lot will require equipment and materials to transit from Long Island to Fire Island. The Smith Point Bridge, the only vehicle access to the Smith Point County Park parking lot, has had its posted weight limitation of 15 tons gross weight due to structural condition issues and concerns over accelerated aging. Due to these weight limitations, Sunrise Wind will utilize a transport barge and temporary landing structure (pier) to transport the heavy construction equipment and materials necessary to construct the Sunrise Wind Farm Project across the Intracoastal Waterway (ICW) to Smith Point County Park. The materials moved using the barge and temporary equipment are required to construct the Project and includes equipment needed to complete the HDD work and onshore civil works that are otherwise too heavy to travel across the Smith Point Bridge. In addition to the temporary pier on Fire Island, temporary mooring and breasting dolphins will be installed near the boat ramp at the Smith Point Marina on the Long Island side of the ICW to facilitate safe loading and unloading of the barge at the Smith Point Marina boat launch on Long Island.
The temporary pier will require the installation of up to 26 total production piles that will remain the entire time the temporary pier is in place. Temporary piles may be used to support a steel-framed template used to ensure installation of the bent production piles in the correct positions. The temporary piles may include up to 24 H-shaped or cylinder piles of the same size as the production piles. Therefore, a total of 50 piles (up to 26 production piles and up to 24 temporary piles) may be installed, and in some cases removed, during construction.
Installation and removal of the up to 24 temporary piles would be completed using only vibratory pile driving equipment. The up to 26 production piles would first be driven using a vibratory hammer followed by an impact hammer. Both production and temporary piles will be removed using vibratory pile driving. It is anticipated that installation of the pier will occur over approximately 3 to 4 weeks in and around December 2023. Installation of up to 26 production piles may result in a total of up to 351 minutes (5 hours 51 min) of vibratory pile driving (26 × 13.5 min) and 39 minutes of impact pile driving (26 × 1.5 min). Installation and removal of up to 24 temporary piles may require up to 720 minutes (16 hours) of vibratory pile driving only (2 × 24 × 15 min). The maximum total pile driving time for installation is therefore 1,071 min (17 hours 51 min) of vibratory pile driving and 39 minutes of impact pile driving. Following completion of the landfall construction work on Fire Island, the temporary pier is expected to be removed in approximately April or May of 2025. Removal of the temporary pier would involve the removal of all 26 production piles using a vibratory hammer. Thus, the total duration of
vibratory pile driving during pier removal may be up to 390 min (6 hours 30 min; 26 × 15 min).
While pile driving would result in Level B harassment isopleths up to approximately 750 m from the piles (as described in Sunrise Wind's Temporary Pier Memo (available at
https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable
), the very short duration of pile driving, the limited harassment area, the location of the harassment area (in an area where marine mammals are not typically present), and the implementation of monitoring and mitigation measures (see Proposed Mitigation and Proposed Monitoring and Reporting sections), Sunrise Wind is not requesting, and NMFS is not proposing to authorize, take of marine mammals incidental to temporary pier and breasting and mooring dolphin construction activities.
Vessel Operation
Sunrise Wind will utilize various types of vessels over the course of the 5-year proposed regulations. Sunrise Wind is evaluating the potential use of several existing port facilities located in New York, Connecticut, Maryland, Massachusetts, New Jersey, Rhode Island, and Virginia to support offshore construction, assembly and fabrication, crew transfer and logistics. The primary construction ports that are expected to be used during construction include: Albany and/or Coeymans, New York; Port of New London, Connecticut; and Port of Dainsville-Quonset Point, Rhode Island.
The largest vessels are expected to be used during the WTG installation phase with floating/jackup crane barges, cable-laying vessels, supply/crew vessels, and associated tugs and barges transporting construction equipment and materials. Large work vessels (
e.g.,
jack-up installation vessels and cable-laying vessels) for foundation and WTG installation will generally transit to the work location and remain in the area until installation time is complete. These large vessels will move slowly over a short distance between work locations. Transport vessels will travel between several ports and the SRWF 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 SRWF.
As part of various vessel-based construction activities, including cable laying and construction material delivery, dynamic positioning thrusters may be utilized to hold vessels in position or move slowly. Sound produced through use of dynamic positioning thrusters is similar to that produced by transiting vessels, and dynamic positioning thrusters are typically operated either in a similarly predictable manner or used for short durations around stationary activities. Sound produced by dynamic positioning thrusters would be preceded by, and associated with, sound from ongoing vessel noise and would be similar in nature; thus, any marine mammals in the vicinity of the activity would be aware of the vessel's presence. Construction-related vessel activity, including the use of dynamic positioning thrusters, is not expected to result in take of marine mammals. Sunrise Wind did not request, and NMFS does not propose to authorize, any take associated with vessel activity.
During operation, up to three crew transfer vessels and a service operation vessel will be used to conduct maintenance activities. Sunrise Wind has also included potential for helicopters to be used in lieu of crew transfer vessels. The use of helicopters is included in Table 3 below; however, it is important to note that Sunrise Wind has indicated that there are a number of uncertainties regarding the how many trips will be made using helicopters, the number of passengers to be carried, and the vessels to which those passengers would be transported. Therefore, the total number of vessel trips shown in Table 3 has not been reduced based on the anticipated helicopter flights. As such, the number of crew transfer vessel trips may be less than depicted here.
Table 3—Type and Number of Vessels and Number of Vessel Trips Anticipated During Construction and Operations
Vessel types
Max
number of
simultaneous
vessels
Max annual
number of
return trips
Wind Turbine Foundation Installation (Yrs 1-2)
Heavy Lift Installation Vessel
2
20
Heavy Transport Vessel
4
50
Platform Supply Vessel
2
80
In-field support tug
2
50
Vessel for Bubble Curtain
1
30
Crew Transport Vessel
1
50
Monitoring Vessel
4
102
Completion Vessel
1
50
Fall Pipe Vessel
1
6
Turbine Installation (Yrs 1-2)
Installation Vessel
1
26
Support Vessel
1
9
Array Cable Installation (Yrs 1-2)
Pre-Lay Grapnel Run
1
5
Boulder Clearance Vessel
1
5
Sandwave Clearance Vessel
1
3
Cable Laying Vessel
3
3
Cable Burial Vessel
2
3
Walk to Work Vessel (SOV)
1
6
Crew Transport Vessel
1
260
Survey Vessel
4
8
Construction Vessel
2
4
Fall Pipe Vessel
2
10
Offshore Converter Station Installation (Yrs 1-2)
Primary Installation Vessel
3
3
Transport Vessel
2
2
Support Vessels
11
5
Fall Pipe Vessel
1
2
Offshore Export Cable Installation (Yrs 1-2)
Pre-Lay Grapnel Run
1
1
Boulder Clearance Vessel
1
1
Sandwave Clearance Vessel
1
1
Cable Laying Vessel
3
6
Cable Burial Vessel
2
4
Tugs
4
8
Crew Transport Vessel
1
260
Guard Vessel/Scout Vessel
5
9
Survey Vessel
2
6
Fall Pipe Vessel
1
2
Construction Vessel
2
2
All Construction Activities (Yrs 1-2)
Safety Vessel
2
114
Crew Transport Vessel
3
300
Jack-up/Lift Boat
1
1
Supply Vessel
1
10
Service Operation Vessel
1
6
Helicopter
2
350
Operations Vessels (Yrs 3-5)
Crew Transport Vessel
3
300
Service Operation Vessel
1
40
Helicopters may be used during Sunrise Wind Farm construction and operation phases for crew transfer activities to provide a reduction in the overall transfer time as well as to reduce the number of vessels on the water. Sunrise Wind estimates crew transfer time could be decreased by 92 percent (16 to 30 minutes via a helicopter versus 3.5 to 6 hours using a vessel). However, use of helicopters may be limited by many factors, such as logistical constraints (
e.g.,
ability to land on the vessels) and weather conditions that affect flight operations. Helicopter use also adds significant health, safety and environment (HSE) risk to personnel and therefore, requires substantially more crew training and additional safety procedures. These factors can result in significant limitations to helicopter usage. The use of helicopters to conduct crew transfers is likely to provide an overall benefit to marine mammals in the form of reduced vessel activity.
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, Sunrise Wind did not request, and NMFS is not proposing to authorize, take of marine mammals incidental to helicopter flights; therefore, it will not be discussed further.
Seafloor Preparation
For export cable installation, seafloor preparation will include required sand wave leveling, boulder clearance, and removal of any out of service cables. Boulder clearance trials may be performed prior to wide-scale seafloor preparation activities to evaluate efficacy of boulder clearing techniques. Additionally, pre-lay grapnel runs (PLGR) will be undertaken to remove any seafloor debris along the export cable route. 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. Rock berm or concrete mattress separation layers will also be installed at the eight known telecommunications cables crossed by the SRWEC and/or inter-array cable (IAC) 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 SRWEC or IAC.
For monopile and jacket pile installation, seafloor preparation will include required boulder clearance and removal of any obstructions within the seafloor preparation area at each foundation location. Scour protection installation will occur prior to installation and will involve a rock dumping vessel placing scour at each foundation location.
Boulder clearance may be required in targeted locations to clear boulders along the SRWEC, inter-array cable (IAC) 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. 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 8 ft (2.5 m) can be relocated with standard tools and equipment. Where required, Sunrise Wind has assumed the route would be cleared of boulders up to 98 feet (30-m) in width along the final SRWEC and IAC centerlines. Around the foundations, Sunrise Wind assumes boulder clearance will occur within a 722-ft (220-m) radius centered on the foundations to ensure safe foundation installation as well as safe vessel jack-up.
Boulder removal would occur prior to installation and would be completed by a support vessel based on pre-construction surveys. 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.
Sand leveling (inclusive of leveling of sand accumulation areas) may be required during seafloor preparation activities prior to installation of the SRWEC. Two installation methods may be used to complete sand leveling including Suction Hopper Dredging and controlled flow excavation (CFE). The dredging technique consists of one or more suction downpipes equipped with a seafloor drag head. The drag head is towed over the sand wave by the vessel while a pump system sucks fluidized sand into the vessel's storage hopper. Any sediment removed would be relocated within the local sand wave field along the SRWEC and IAC using continuous overflow from the vessel. Alternatively, the removed sediment can be caught in the hopper storage and the vessel can relocate to a designated storage or disposal area and either offload material through a hatch in the vessel's hull or more carefully position material subsea using a downpipe. CFE is a contactless dredging tool, providing a method of clearing loose sediment below submarine cables, enabling burial. CFE utilizes thrust to direct waterflow into sediment, creating liquefaction and subsequent dispersal. The CFE tool draws in seawater from the sides and then jets this water out from a vertical down pipe at a specified pressure and volume, which is then positioned over the cable alignment, enabling the stream of water to fluidize the sands around the cable. This allows the cable to settle into the trench under its own weight.
NMFS does not expect site preparation work, including boulder removal and sand leveling, to generate noise levels that would cause take of marine mammals. Underwater noise associated with these activities is expected to be similar in nature to the sound produced by the dynamic positioning (DP) cable lay vessels used during cable installation activities within the SRWEC. Sound produced by DP vessels is considered non-impulsive and is typically more dominant than mechanical or hydraulic noises produced from the cable trenching or boulder removal vessels and equipment. Therefore, noise produced by the high bollard pull vessel with a towed plow or a support vessel carrying a boulder grab would be comparable to or less than the noise produced by DP vessels, so impacts are also expected to be similar. Boulder clearance is a discreet action occurring over a short duration resulting in short term direct effects. Additionally, sound produced by boulder clearance vessels and equipment would be preceded by, and associated with, sound from ongoing vessel noise and would be similar in nature.
NMFS expects that marine mammals would not be exposed to sounds levels or durations from seafloor preparation work that would disrupt behavioral patterns. Therefore, the potential for take of marine mammals to result from these activities is discountable and Sunrise Wind did not request, and NMFS does not propose to authorize, any takes associated with seafloor preparation work and these activities are not analyzed further in this document.
Fisheries and Benthic Monitoring
Fisheries and benthic monitoring surveys have been designed for the Project in accordance with recommendations set forth in “Guidelines for Providing Information on Fisheries for Renewable Energy Development on the Atlantic Outer Continental Shelf” (BOEM 2019). Sunrise Wind would conduct trawl surveys, acoustic telemetry studies, benthic habitat monitoring using a remotely operated vehicle (ROV), video surveillance, grab surveys, and Habcam surveys using towed video surveillance. Because the gear types and equipment used for the acoustic telemetry study, benthic habitat monitoring, and Habcam surveys do not have components with which marine mammals are likely to interact (
i.e.,
become entangled in or hooked by), these activities are unlikely to have any impacts on marine mammals. Therefore, only trawl surveys, in general, have the potential to result in harassment to marine mammals. However, Sunrise Wind would implement mitigation and monitoring measures to avoid taking marine mammals, including, but not limited to, monitoring for marine mammals before and during trawling activities, not deploying or pulling trawl gear in certain circumstances, limiting tow times, and fully repairing nets. A full description of mitigation measures can be found in the Proposed Mitigation section.
With the implementation of these measures, Sunrise Wind does not anticipate, and NMFS is not proposing to authorize, take of marine mammals incidental to research trawl surveys. Any lost gear associated with the fishery surveys will be reported to the NOAA Greater Atlantic Regional Fisheries Office Protected Resources Division as soon as possible. Given no take is anticipated from these surveys, impacts from fishery surveys will not be discussed further in this document.
Description of Marine Mammals in the Area of Specified Activities
Thirty-nine marine mammal species (comprising 40 stocks) have geographic ranges within the western North Atlantic OCS (Hayes et al., 2022). However, for reasons described below, Sunrise Wind has requested, and NMFS proposes to authorize, take of only 16 species (comprising 16 stocks) of marine mammals. Sections 3 and 4 of Sunrise Wind's application summarize available information regarding status and trends, distribution and habitat preferences, and behavior and life history of the potentially affected species (Sunrise Wind, 2021). 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
).
Table 4 lists all species and stocks for which take is expected and proposed to be authorized for this action and summarizes information related to the population or stock, including regulatory status under the MMPA and Endangered Species Act (ESA) and potential biological removal (PBR) level, where known. The MMPA defines PBR as “the maximum number of animals, not including natural mortalities, that may be removed from a marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population” (16 U.S.C. 1362(20)) PBR values are identified in NMFS's SARs. While no mortality is anticipated or proposed to be authorized, PBR and annual serious injury and mortality from anthropogenic sources are included here as gross indicators of the status of the species and other threats.
Marine mammal abundance estimates presented in this document represent the total number of individuals that make up a given stock or the total number estimated within a particular study or survey area. NMFS's stock abundance estimates for most species represent the total estimate of individuals within the geographic area, if known, that comprises that stock. For some stocks, this geographic area may extend beyond U.S. waters. All managed stocks in this region are assessed in NMFS's U.S. Atlantic and Gulf of Mexico SARs. All values presented in Table 4 are the most recent available at the time of publication and are available in NMFS' 2021 SARs (Hayes
et al.,
2022) available online at:
https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports.
Table 4—Marine Mammal Species Likely To Occur Near the Project Area That May Be Taken by Sunrise Wind's Activities
Common name
Scientific name
Stock
ESA/
MMPA
status;
strategic
(Y/N)
1
Stock
abundance (CV, N
min
, most recent
abundance survey)
2
PBR
Annual M/SI
3
Order Artiodactyla—Cetacea—Superfamily Mysticeti (baleen whales)
Family Balaenidae:
North Atlantic right whale
Eubalaena glacialis
Western Atlantic
E, D, Y
368 (0; 364; 2019)
5
0.7
7.7
Family Balaenopteridae (rorquals)
Blue whale
Balaenoptera musculus
Western North Atlantic
E, D, Y
UNK (UNK; 402; 1980-2008)
0.8
0
Fin whale
Balaenoptera physalus
Western North Atlantic
E, D, Y
6,802 (0.24; 5,573; 2016)
11
1.8
Sei whale
Balaenoptera borealis
Nova Scotia
E, D, Y
6,292 (1.02; 3,098; 2016)
6.2
0.8
Minke whale
Balaenoptera acutorostrata
Canadian Eastern Coastal
-, -, N
21,968 (0.31; 17,002; 2016)
170
10.6
Humpback whale
Megaptera novaeangliae
Gulf of Maine
-, -, Y
1,396 (0; 1,380; 2016)
22
12.15
Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
Family Physeteridae:
Sperm whale
Physeter macrocephalus
North Atlantic
E, D, Y
4,349 (0.28; 3,451; 2016)
3.9
0
Family Delphinidae
Atlantic white-sided dolphin
Lagenorhynchus acutus
Western North Atlantic
-, -, N
93,233 (0.71; 54,433; 2016)
544
27
Atlantic spotted dolphin
Stenella frontalis
Western North Atlantic
-, -, N
39,921 (0.27; 32,032; 2016)
320
0
Common bottlenose dolphin
Tursiops truncatus
Western North Atlantic Offshore
-, -, N
62,851 (0.23; 51,914; 2016)
519
28
Long-finned pilot whales
Globicephala melas
Western North Atlantic
-, -, N
39,215 (0.3; 30,627; 2016)
306
29
Common dolphin (short-beaked)
Delphinus delphis
Western North Atlantic
-, -, N
172,974 (0.21; 145,216; 2016)
1,452
390
Risso's dolphin
Grampus griseus
Western North Atlantic
-, -, N
35,215 (0.19; 30,051; 2016)
301
34
Family Phocoenidae (porpoises):
Harbor porpoise
Phocoena
Gulf of Maine/Bay of Fundy
-, -, N
95,543 (0.31; 74,034; 2016)
851
16
Order Carnivora—Superfamily Pinnipedia
Family Phocidae (earless seals)
Gray seal
4
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
1
ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
2
NMFS marine mammal stock assessment reports online at:
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments
(Hayes
et al.,
2022). CV is the coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable.
3
These values, found in NMFS' SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (
e.g.,
commercial fisheries, ship strike).
4
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.
5
The values represent abundance estimates from NMFS 2021 Stock Assessment Report (Hayes
et al.,
2022). On Monday, October 24, 2022, the North Atlantic Right Whale Consortium announced that the North Atlantic right whale population estimate for 2021 was 340 individuals. NMFS' website also indicates that less than 350 animals remain (
https://www.fisheries.noaa.gov/species/north-atlantic-right-whale
).
Of the 40 marine mammal species and/or stocks with geographic ranges that include the western North Atlantic OCS (Table 5 in Sunrise Wind ITA application), 24 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. The following species are not expected to occur in the project area due to the location of preferred habitat outside the SRWF and SRWEC based on the best scientific information available: Dwarf and pygmy sperm whales (
Kogia sima and K breviceps
), northern bottlenose whale (
hyperoodon ampullatus
), cuvier's beaked whale (
Ziphius cavirostris
), four species of Mesoplodont beaked whales (
Mesoplodon densitostris, M. europaeus, M. mirus, and M. bidens
), killer whale (
Orcinus orca
), false killer whale (
Pseudorca crassidens
), pygmy killer whale (
Feresa attenuate
), short-finned pilot whale (
Globicephalus macrohynchus
), melon-headed whale (
Peponocephala electra
), Fraser's dolphin (
Lagenodelphis hosei
), white-beaked dolphin (
Lagenorhynchus albirotris
), pantropical spotted dolphin (
Stenella attenuata
), Clymene dolphin (
Stenella clymene
), striped dolphin (
Stenella coeruleoalba
), spinner dolphin (
Stenella longirostris
), rough-toothed dolphin (
Steno bredanensis
), and the northern migratory coastal stock of common bottlenose dolphins (
Tursiops truncatus truncatus
). The following species may occur in the project area but at such low densities that take is not anticipated: hooded seal (
Cystophora cristata
) and harp seal (
Pagophilus groenlandica
).
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 Northeast region during summer months (U.S. Fish and Wildlife Service (USFWS, 2019). However, manatees are managed by the USFWS and are not considered further in this document.
Between October 2011 and June 2015, a total of 76 aerial surveys were conducted throughout the MA and RI/MA WEAs (the SRWF is contained within the RI/MA WEA along with several other offshore renewable energy Lease Areas). Between November 2011 and March 2015, Marine Autonomous Recording Units (MARU; a type of static passive acoustic monitoring (PAM) recorder) were deployed at nine sites in the MA and RI/MA WEAs. The goal of the study was to collect visual and acoustic baseline data on distribution, abundance, and temporal occurrence patterns of marine mammals (Kraus
et al.,
2016). The New England Aquarium conducted additional aerial surveys throughout the MA and RI/MA WEAs from February 2017 through July 2018 (38 surveys), October 2018 through August 2019 (40 surveys), and March 2020 through July 2021 (12 surveys) (Quintana and Kraus, 2019; O'Brien
et al.,
2021a; O'Brien
et al.,
2021b). The lack of detections of any of the 24 species listed above during these surveys reinforces the fact that they are not expected to occur in the project area. In addition, none of these species were observed during HRG surveys conducted by Orsted in from 2018 to 2021. As these species are not expected to occur in the project area during the proposed activities, NMFS does not propose to authorize take of these species, and they are not discussed further in this document.
As indicated above, all 16 species and stocks in Table 4 temporally and spatially co-occur with the activity to the degree that take is reasonably likely to occur. Five of the marine mammal species for which take is requested are listed as threatened or endangered under the ESA: North Atlantic right, blue, fin, sei, and sperm whales. In addition to what is included in Sections 3 and 4 of Sunrise Wind's ITA application (
https://www.fisheries.noaa.gov/action/incidental-take-authorization-sunrise-wind-llc-construction-and-operation-sunrise-wind
), the SARs (
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments
), and NMFS' website (
https://www.fisheries.noaa.gov/species-directory/marine-mammals
), we provide further detail below informing the baseline for select species (
e.g.,
information regarding current Unusual Mortality Events (UME) and known important habitat areas, such as Biologically Important Areas (BIAs) (Van Parijs, 2015)). There are no ESA-designated critical habitats for any species within the project area.
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 November 7, 2022, seven UMEs are active. Five of these UMEs are occurring along the U.S. Atlantic coast for various marine mammal species; of these, the most relevant to the Sunrise Wind project are the minke whale, North Atlantic right whale, humpback whale, and harbor and gray seal UMEs given the prevalence of these species in the project area. More information on UMEs, including all active, closed, or pending, can be found on NMFS' website at
https://www.fisheries.noaa.gov/national/marine-life-distress/
active-and-closed-unusual-mortality-events.
Below we include information for a subset of the species that presently have an active or recently closed UME occurring along the Atlantic coast or for which there is information available related to areas of biological significance. For the majority of species potentially present in the specific geographic region, NMFS has designated only a single generic stock (
e.g.,
“western North Atlantic”) for management purposes. This includes the “Canadian east coast” stock of minke whales, which includes all minke whales found in U.S. waters and is also a generic stock for management purposes. For humpback and sei whales, NMFS defines stocks on the basis of feeding locations (
i.e.,
Gulf of Maine and Nova Scotia, respectively). However, references to humpback whales and sei whales in this document refer to any individuals of the species that are found in the project area. Any areas of known biological importance (including the BIAs identified in 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's enactment in 1973. The species was recently uplisted from Endangered to Critically Endangered on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species (Cooke, 2020). The uplisting was due to a decrease in population size (Pace
et al.,
2017), an increase in vessel strikes and entanglements in fixed fishing gear (Daoust
et al.,
2017; Davis & Brillant, 2019; Knowlton
et al.,
2012; Knowlton
et al.,
2022; Moore
et al.,
2021; Sharp
et al.,
2019), and a decrease in birth rate (Pettis
et al.,
2021; Reed
et al.,
2022). 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 and 2017 (NOAA Fisheries, 2012; NOAA Fisheries, 2017). In February 2022, NMFS initiated a subsequent 5-year review process (
https://www.fisheries.noaa.gov/action/initiation-5-year-review-north-atlantic-right-whale
). Designated by NMFS as a Species in the Spotlight, the North Atlantic right whale is considered among the species with the greatest risk of extinction in the near future (
https://www.fisheries.noaa.gov/topic/endangered-species-conservation/species-in-the-spotlight
).
The North Atlantic right whale population had only a 2.8 percent recovery rate between 1990 and 2011 and an overall abundance decline of 23.5percent from 2011-2019 (Hayes
et al.
2022). Since 2010, the North Atlantic right whale population has been in decline (Pace
et al.,
2017; Pace
et al.,
2021), with a 40 percent decrease in calving rate (Kraus
et al.,
2016; Moore
et al.,
2021). North Atlantic right whale calving rates dropped from 2017 to 2020 with zero births recorded during the 2017-2018 season. The 2020-2021 calving season had the first substantial calving increase in 5 years with 20 calves born followed by 15 calves during the 2021-2022 calving season. However, mortalities continue to outpace births, and best estimates indicate fewer than 100 reproductively active females remain in the population. Presently, the best available peer-reviewed population estimate for North Atlantic right whales is 368 per the 2021 SARs (Hayes
et al.,
2022). As of this writing, the draft 2022 SARs have yet to be released; however, as reflected on NMFS' species web page, new estimates indicate that the right whale population has continued to decline to fewer than 350 animals (
https://www.fisheries.noaa.gov/species/north-atlantic-right-whale
). We note that the application of either abundance estimate in our analysis would not change the estimated take of right whales or the take NMFS has proposed to authorize as take estimates are based on the habitat-density models (Roberts and Halpin 2022).
Since 2017, dead, seriously injured, or sublethally injured or ill North Atlantic right whales along the U.S. and Canadian coasts have been documented, necessitating a UME declaration and investigation. The leading category for the cause of death for this ongoing UME is “human interaction,” specifically from entanglements or vessel strikes. As of January 12, 2023, there have been 35 confirmed mortalities (dead stranded or floaters; 21 in Canada; 14 in the United States) and 22 seriously injured free-swimming whales for a total of 57 whales. Beginning on October 14, 2022, the UME also considers animals with sublethal injury or illness bringing the total number of whales in the UME to 94. 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.
North Atlantic right whale presence in the project area is predominately seasonal; however, year-round occurrence is documented with irregular occurrence during summer months (O'Brien
et al.,
2022, Quintano-Rizzo
et al.,
2021). As a result of recent years of aerial surveys and PAM deployments within the RI/MA WEA, we have confidence that North Atlantic right whales are expected in the project area with higher numbers of animals present in winter and spring followed by decreasing abundance into summer and early fall (
e.g.,
(O'Brien
et al.,
2022, Quintano-Rizzo
et al.,
2021). The project area both spatially and temporally overlaps a portion of the migratory corridor BIA within which North Atlantic right whales migrate south to calving grounds generally in November and December, followed by a northward migration into feeding areas east and north of the project area in March and April (LaBrecque
et al.,
2015; Van Parijs
et al.,
2015). While the project does not overlap previously identified critical feeding habitat or a feeding BIA, it is located west of a more recently described important feeding area south of Martha's Vineyard and Nantuck
et al
ong the western side of Nantucket Shoals. Finally, the project overlaps the currently established November 1 through April 30th Block Island Seasonal Management Area (SMA) (73 FR 60173, October 10, 2008) and the proposed November 1 through May 30th Atlantic Seasonal Speed Zone (87 FR 46921, August 1, 2022), which may be used by North Atlantic right whales for various activities, including feeding and migration. Due to the current status of North Atlantic right whales and the overlap of the proposed project with areas of biological significance (
i.e.,
a migratory corridor, SMA), the potential impacts of the proposed project on North Atlantic right whales warrant particular attention.
Southern New England and New York waters are both a migratory corridor in the spring and early winter and a primary feeding habitat for North Atlantic right whales during late winter through spring. North Atlantic right whales feed primarily on the copepod
Calanus finmarchicus,
a species whose availability and distribution has changed both spatially and temporally over the last decade due to an oceanographic regime shift that has been ultimately linked to climate change (Meyer-Gutbrod
et al.,
2021;
Record
et al.,
2019; Sorochan
et al.,
2019). This distribution change in prey availability has led to shifts in North Atlantic right whale habitat-use patterns within the region over the same time period (Davis
et al.,
2020; Meyer-Gutbrod
et al.,
2022; Quintano-Rizzo
et al.,
2021, O'Brien
et al.,
2022). Since 2010, North Atlantic right whales have reduced their use of foraging habitats in the Great South Channel and Bay of Fundy while increasing their use of habitat within Cape Cod Bay as well as a region south of Martha's Vineyard and Nantucket Islands to the east of the SRWF and SRWEC corridor (Stone
et al.,
2017; Mayo
et al.,
2018; Ganley
et al.,
2019; Record
et al.,
2019; Meyer-Gutbrod
et al.,
2021). Pendleton
et al.
(2022) found that peak use of North Atlantic right whale foraging habitat in Cape Cod Bay has shifted over the past 20 years to later in the spring, likely due to variations in seasonal conditions. However, initial sightings of individual North Atlantic right whales in Cape Cod Bay have started earlier, indicating that they may be using regional water temperature as a cue for migratory movements between habitats (Ganley
et al.
2022). North Atlantic right whales have recently been observed feeding year-round in the region south of Martha's Vineyard and Nantucket (Quintana-Rizzo
et al.,
2021) with larger numbers in this area in the winter making it the only known winter foraging habitat for the species (Leiter
et al.,
2017). North Atlantic right whale use of habitats, such as in the Gulf of St. Lawrence and East Coast mid-Atlantic waters of the United States., have also increased over time (Davis
et al.,
2017; Davis and Brillant, 2019; Crowe
et al.,
2021; Quintana-Rizzo
et al.,
2021). Simard
et al.
(2019) documented the presence of North Atlantic right whales in the southern Gulf of St. Lawrence foraging habitat from late April through mid-January annually from 2010-2018 using passive acoustics with occurrences peaking in the area from August through November each year (Simard
et al.,
2019). Observations of these transitions in North Atlantic right whale habitat use, variability in seasonal presence in identified core habitats, and utilization of habitat outside of previously focused survey effort prompted the formation of a NMFS' Expert Working Group, which identified current data collection efforts, data gaps, and provided recommendations for future survey and research efforts (Oleson
et al.,
2020).
Around November, a portion of the North Atlantic right whale population (including pregnant females) typically departs the feeding grounds in the North Atlantic, move south along the migratory corridor BIA, including through the project area, to North Atlantic right whale calving grounds off Georgia and Florida. However, recent research indicates understanding of their movement patterns remains incomplete and not all of the population undergoes a consistent annual migration (Davis
et al.,
2017; Gowan
et al.,
2019; Krzystan
et al.,
2018). The results of multistate temporary emigration capture-recapture modeling, based on sighting data collected over the past 22 years, indicate that non-calving females may remain in the feeding grounds during the winter in the years preceding and following the birth of a calf to increase their energy stores (Gowen
et al.,
2019).
Within the project area, North Atlantic right whales have primarily been observed during the winter and spring seasons through recent visual surveys (Kraus
et al.,
2016; Quintana-Rizzo
et al.,
2021). During aerial surveys conducted in the RI/MA and MA WEAs from 2011-2015, the highest number of North Atlantic right whale sightings occurred in March (n=21), with sightings also occurring in December (n=4), January (n=7), February (n=14), and April (n=14), and no sightings in any other months (Kraus
et al.,
2016). There was not significant variability in sighting rate among years, indicating consistent annual seasonal use of the area by North Atlantic right whales. Despite the lack of visual detection, North Atlantic right whales were acoustically detected in 30 out of the 36 recorded months (Kraus
et al.,
2016). Since 2017, whales have been sighted in the southern New England area nearly every month with peak sighting rates between late winter and spring. Model outputs suggest that 23 percent of the North Atlantic right whale population is present from December through May, and the mean residence time has tripled to an average of 13 days during these months (Quintano-Rizzo
et al.,
2021).
North Atlantic right whale distribution can also be derived from acoustic data. A review of passive acoustic monitoring data from 2004 to 2014 collected throughout the western North Atlantic demonstrated nearly continuous year-round North Atlantic right whale presence across their entire habitat range with a decrease in summer months, including in locations previously thought of as migratory corridors suggesting that not all of the population undergoes a consistent annual migration (Davis
et al.,
2017). To describe seasonal trends in North Atlantic right whale presence, Estabrook
et al.
(2022) analyzed North Atlantic right whale acoustic detections collected between 2011-2015 during winter (January-March), spring (April-June), summer (July-September), and autumn (October-December). Winter had the highest presence (75percent array-days, n = 193), and summer had the lowest presence (10percent array-days, n = 27). Spring and autumn were similar, where 45percent (n = 117) and 51percent (n = 121) of the array-days had detections, respectively. Across all years, detections were consistently lowest in August and September. In Massachusetts Bay and Cape Cod Bay, located outside of the project area, acoustic detections of North Atlantic right whales increased in more recent years in both the peak season of late winter through early spring and in summer and fall, likely reflecting broadscale regional habitat changes (Charif
et al.,
2020). NMFS' Passive Acoustic Cetacean Map (PACM) contains up-to-date acoustic data that contributes to our understanding of when and where specific whales (including North Atlantic right whales), dolphin, and other cetacean species are acoustically detected in the North Atlantic. These data support the findings of the aforementioned literature.
While density data from Roberts
et al.
(2022) confirm that the highest average density of North Atlantic right whales in the project area (both the lease area and SRWEC corridor) occurs in May (0.0018 whales/km
2
), which aligns with available sighting and acoustic data, it is clear that that habitat use is changing and North Atlantic right whales are present to some degree in or near the project area throughout the year, most notably south of Martha's Vineyard and Nantucket Islands (Leiter
et al.,
2017; Stone
et al.,
2017; Oleson
et al.,
2020, Quintano-Rizzo
et al.,
2021). Since 2010, North Atlantic right whale abundances have increased in Southern New England waters, south of Martha's Vineyard and Nantucket Islands. O'Brien
et al.
(2022) detected significant increases in North Atlantic right whale abundance during winter and spring seasons from 2013-2019 likely due to changes in prey availability. Since 2017, North Atlantic right whales were also detected in small numbers during summer and fall, suggesting that southern New England waters provide year-round habitat for North Atlantic right whales (O'Brien
et al.,
2022).
NMFS' regulations at 50 CFR 224.105 designate nearshore waters of the Mid-Atlantic Bight as the Mid-Atlantic U.S. SMAs for North Atlantic right whales in 2008. These specific SMAs were
developed to reduce the threat of collisions between ships and North Atlantic right whales around their migratory route and calving grounds. As mentioned previously, the Block Island SMA overlaps spatially with 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 North Atlantic right whales for feeding (although to a lesser extent than the area to the east near Nantucket Shoals) and/or migrating. As noted above, NMFS is proposing changes to the North Atlantic right whale speed rule (87 FR 46921; August 1, 2022).
Humpback Whale
Humpback whales were listed as endangered under the Endangered Species Conservation Act (ESCA) in June 1970. In 1973, the ESA replaced the ESCA, and humpbacks continued to be listed as endangered. On September 8, 2016, NMFS divided the once single species into 14 distinct population segments (DPS), removed the species-level listing, and, in its place, listed 4 DPSs as endangered and 1 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 CI 8,688-15,954) whales in 2004-05, which is consistent with previous population estimates of approximately 10,000-11,000 whales (Stevick
et al.,
2003; Smith
et al.,
1999) and the increasing trend for the West Indies DPS (Bettridge
et al.,
2015).
In New England waters, feeding is the principal activity of humpback whales, and their distribution in this region has been largely correlated to abundance of prey species (Payne
et al.,
1986, 1990). Humpback whales are frequently piscivorous when in New England waters, feeding on herring (
Clupea harengus
), sand lance (
Ammodytes spp.
), and other small fishes, as well as euphausiids in the northern Gulf of Maine (Paquet
et al.,
1997). Kraus
et al.
(2016) observed humpbacks in the RI/MA & MA WEAs and surrounding areas during all seasons but most often during spring and summer months with a peak from April to June. Acoustic data indicate that this species may be present within the RI/MA WEA year-round with the highest rates of acoustic detections in the winter and spring (Kraus
et al.,
2016).
The project area does not overlap any ESA-designated critical habitat, BIAs, or other important areas for the humpback whales. A humpback whale feeding BIA extends throughout the Gulf of Maine, Stellwagen Bank, and Great South Channel from May through December, annually (LeBrecque
et al.,
2015). However, this BIA is located further east and north of, and thus, does not overlap, the project area.
Since January 2016, elevated humpback whale mortalities along the Atlantic coast from Maine to Florida led to the declaration of a UME. As of January 12, 2023, 174 humpback whales have stranded as part of this UME. Partial or full necropsy examinations have been conducted on approximately half of the 161 known cases (as of November 7, 2022). Of the whales examined, about 50 percent had evidence of human interaction, either ship strike or entanglement. While a portion of the whales have shown evidence of pre-mortem vessel strike, this finding is not consistent across all whales examined and more research is needed. 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.
Fin Whale
Fin whales typically feed in the Gulf of Maine and the waters surrounding New England, but their mating and calving (and general wintering) areas are largely unknown (Hain
et al.
1992, Hayes
et al.
2022). Acoustic detections of fin whale singers augment and confirm these visual sighting conclusions for males. Recordings from Massachusetts Bay, New York Bight, and deep-ocean areas have detected some level of fin whale singing from September through June (Watkins
et al.
1987, Clark and Gagnon 2002, Morano
et al.
2012). These acoustic observations from both coastal and deep-ocean regions support the conclusion that male fin whales are broadly distributed throughout the western North Atlantic for most of the year (Hayes
et al.
2022).
Kraus
et al.
(2016) suggest that, compared to other baleen whale species, fin whales have a high multi-seasonal relative abundance in the RI/MA & MA WEAs and surrounding areas. Fin whales were observed in the MA WEA in spring and summer. This species was observed primarily in the offshore (southern) regions of the RI/MA & MA WEAs during spring and was found closer to shore (northern areas) during the summer months (Kraus
et al.,
2016). Calves were observed three times and feeding was observed nine times during the Kraus
et al.
(2016) study. Although fin whales were largely absent from visual surveys in the RI/MA & MA WEAs in the fall and winter months (Kraus
et al.,
2016), acoustic data indicated that this species was present in the RI/MA & MA WEAs during all months of the year.
New England waters represent a major feeding ground for fin whales. Almost the entire lease area (351 km
2
) overlaps approximately 12 percent of a relatively small fin whale feeding BIA (2,933 km
2
) offshore of Montauk Point, New York from March to October (Hain
et al.,
1992; LaBrecque
et al.
2015). A separate larger year-round feeding BIA (18,015 km
2
) located far to the northeast in the southern Gulf of Maine does not overlap with the project area and would thus not be impacted by project activities.
Minke Whale
Minke whale occurrence is common and widespread in New England from spring to fall, although the species is largely absent in the winter (Hayes
et al.,
2022; Risch
et al.,
2013). Surveys conducted in the RI/MA WEAs from October 2011 through June 2015 reported 103 minke whale sightings within the area, predominantly in the spring followed by summer and fall (Kraus
et al.,
2016). Recent surveys conducted in the RI/MA WEAs from February 2017 through July 2018, October 2018 through August 2019, and March 2020 through July 2021 documented minke whales as the most common rorqual (baleen whales with pleated throat grooves) sighted in the WEAs. Surveys also reported a shift in the greatest seasonal abundance of minke whales from spring (2017-2018) (Quintana and Kraus, 2018) to summer (2018-2019 and 2020-2021) (O'Brien
et al.,
2021a, b).
There are two minke whale feeding BIAs identified in the southern and southwestern section of the Gulf of Maine, including Georges Bank, the Great South Channel, Cape Cod Bay and Massachusetts Bay, Stellwagen Bank, Cape Anne, and Jeffreys Ledge from March through November, annually (LeBrecque
et al.,
2015). However, these BIAs do not overlap the project area as they are located further east and north. A migratory route for minke whales transiting between northern feeding grounds and southern breeding areas
may exist to the east of the proposed project area as minke whales may trac warmer waters along the continental shelf while migrating (Risch
et al.,
2014).
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 January 12 2023, a total of 136 minke whales have stranded during this UME. Full or partial necropsy examinations were conducted on more than 60 percent of the whales. Preliminary findings in several of the whales have shown evidence of human interactions or infectious disease, but these findings are not consistent across all of the minke whales examined, so more research is needed. More information is available at:
https://www.fisheries.noaa.gov/national/marine-life-distress/2017-2022-minke-whale-unusual-mortality-event-along-atlantic-coast.
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 Sunrise Wind project area, the populations affected by the UME are the same as those potentially affected by the project.
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:
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 5.
Table 5—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. Sixteen marine mammal species (14 cetacean species (6 mysticetes and 8 odontocetes) and 2 pinniped species (both phocid)) have the reasonable potential to co-occur with the proposed project activities (Table 4).
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 to 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.
Sunrise Wind has requested authorization to take marine mammals incidental to construction activities associated with in the Sunrise Wind project area. In the ITA application, Sunrise Wind presented analyses of potential impacts to marine mammals from use of acoustic and explosive sources. NMFS carefully reviewed the information provided by Sunrise Wind and independently reviewed applicable scientific research and literature and other information to evaluate the potential effects of Sunrise Wind's activities on marine mammals.
The proposed activities would result in placement of up to 95 permanent foundations (94 WTGs and 1 OCS-DC) and a temporary casing pipe in the marine environment. Up to three UXO/MEC detonations may occur during construction if any found UXO/MEC cannot be removed by other means. There are a variety of types and degrees of effects to marine mammals, prey species, and habitat that could occur as a result of the project. Below we provide a brief description of the types of sound sources that would be generated by the project, the general impacts from these types of activities, and an analysis of the anticipated impacts on marine mammals from the project in 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 μPa
2
-s). SEL is a cumulative metric; it can be accumulated over a single pulse (for pile driving this is often referred to as single-strike SEL; SEL
ss
) 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). Peak pressure is also used to evaluate the potential for gastro-intestinal tract injury (Level A harassment) from explosives.
For explosives, an impulse metric (Pa-s), which is the integral of a transient sound pressure over the duration of the pulse, is used to evaluate the potential for mortality (
i.e.,
severe lung injury) and slight lung injury. These impulse metric thresholds account for animal mass and depth.
Sounds can be either impulsive or non-impulsive. The distinction between these two sound types is important because they have differing potential to cause physical effects, particularly with regard to hearing
(e.g.,
Ward, 1997 in Southall
et al.,
2007). Please see NMFS
et al.
(2018) and Southall
et al.
(2007,
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 (ANSI, 1986, 2005; Harris, 1998; NIOSH, 1998; 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 (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 southeast of Rhode Island 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.
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 Sunrise Wind 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). Potential effects from explosive sound sources can range in severity from behavioral disturbance or tactile perception to physical discomfort, slight injury of the internal organs and the auditory system, or mortality (Yelverton
et al.,
1973).
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 Sunrise Wind.
Richardson
et al.
(1995) described zones of increasing intensity of effect that might be expected to occur in relation to distance from a source and assuming that the signal is within an animal's hearing range. First (at the greatest distance) is the area within which the acoustic signal would be audible (potentially perceived) to the animal but not strong enough to elicit any overt behavioral or physiological response. The next zone (closer to the receiving animale) 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 Sunrise Wind plans to conduct, to the degree it is available (noting that there is limited information regarding the impacts of offshore wind construction on marine mammals).
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 (
Neophocoena asiaeorientalis
)) and six species of pinnipeds (northern elephant seal (
Mirounga angustirostris
), harbor seal, ring seal, spotted seal, bearded seal, and California sea lion (
Zalophus californianus
)) that were exposed to a limited number of sound sources (
i.e.,
mostly tones and octave-band noise with limited number of exposure to impulsive sources such as seismic airguns or impact pile driving) in laboratory settings (Southall
et al.,
2019). There is currently no data available on noise-induced hearing loss for mysticetes. For summaries of data on TTS or PTS in marine mammals or for further discussion of TTS or PTS onset thresholds, please see Southall
et al.
(2019), and NMFS (2018).
Recent studies with captive odontocete species (bottlenose dolphin, harbor porpoise, beluga, and false killer whale) have observed increases in hearing threshold levels when individuals received a warning sound prior to exposure to a relatively loud sound (Nachtigall and Supin, 2013, 2015, Nachtigall
et al.,
2016a,b,c, 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 Disturbance
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 (Nowacek
et al.,
2007; DeRuiter
et al.,
2012 and 2013; Ellison
et al.,
2012; Gomez
et al.,
2016) 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. 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 MF 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; Dunlop
et al.,
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 sixfold 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 or 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.,
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; Malme
et al.,
1984). Longer-term displacement is possible, however, which may lead to changes in abundance or distribution patterns of the affected species in the affected region if habituation to the presence of the sound does not occur (
e.g.,
Blackwell
et al.,
2004; Bejder
et al.,
2006; Teilmann
et al.,
2006; Forney
et al.,
2017). Avoidance of marine mammals during the construction of offshore wind facilities (specifically, impact pile driving) has been documented in the literature with some significant variation in the temporal and spatial degree of avoidance and with most studies focused on harbor porpoises as one of the most common marine mammals in European waters (
e.g.,
Tougaard
et al.,
2009; Dähne
et al.,
2013; Thompson
et al.,
2013; Russell
et al.,
2016; Brandt
et al.,
2018).
Available information on impacts to marine mammals from pile driving associated with offshore wind is limited to information on harbor porpoises and seals, as the vast majority of this research has occurred at European offshore wind projects where large whales and other odontocete species are uncommon. Harbor porpoises and harbor seals are considered to be behaviorally sensitive species (
e.g.,
Southall
et al.,
2007) and the effects of wind farm construction in Europe on these species has been well documented. These species have received particular attention in European waters due to their abundance in the North Sea (Hammond
et al.,
2002; Nachtsheim
et al.,
2021). A summary of the literature on documented effects of wind farm construction on harbor porpoise and harbor seals is described below.
Brandt
et al.
(2016) summarized the effects of the construction of eight offshore wind projects within the German North Sea (
i.e.,
Alpha Ventus, BARD Offshore I, Borkum West II, DanTysk, Global Tech I, Meerwind Süd/Ost, Nordsee Ost, and Riffgat) between 2009 and 2013 on harbor porpoises, combining PAM data from 2010-2013 and aerial surveys from 2009-2013 with data on noise levels associated with pile driving. Results of the analysis revealed significant declines in porpoise detections during pile driving when compared to 25-48 hours before pile driving began, with the magnitude of decline during pile driving clearly decreasing with increasing distances to the construction site. During the majority of projects, significant declines in detections (by at least 20 percent) were found within at least 5-10 km of the pile driving site, with declines at up to 20-30 km of the pile driving site documented in some cases. Similar results demonstrating the long-distance displacement of harbor porpoises (18-25 km) and harbor seals (up to 40 km) during impact pile driving have also been observed during the construction at multiple other European wind farms (Haleters
et al.,
2015; Lucke
et al.,
2012; Dähne
et al.,
2013; Tougaard
et al.,
2009; Bailey
et al.,
2010.)
While harbor porpoises and seals tend to move several kilometers away from wind farm construction activities, the duration of displacement has been documented to be relatively temporary. In two studies at Horns Rev II using impact pile driving, harbor porpoise returned within 1-2 days following cessation of pile driving (Tougaard
et al.,
2009, Brandt
et al.,
2011). Similar recovery periods have been noted for harbor seals off England during the construction of four wind farms (Carroll
et al.,
2010; Hamre
et al.,
2011; Hastie
et al.,
2015; Russell
et al.,
2016; Brasseur
et al.,
2010). In some cases, an increase in harbor porpoise activity has been documented inside wind farm areas following construction (
e.g.,
Lindeboom
et al.,
2011). Other studies have noted longer term impacts after impact pile driving. Near Dogger Bank in Germany, harbor porpoises continued to avoid the area for over 2 years after construction began (Gilles
et al.
2009). Approximately 10 years after construction of the Nysted wind farm, harbor porpoise abundance had not recovered to the original levels previously seen, although the echolocation activity was noted to have been increasing when compared to the previous monitoring period (Teilmann and Carstensen, 2012). However, overall, there are no indications for a population decline of harbor porpoises in European waters (
e.g.,
Brandt
et al.,
2016). Notably, where significant differences in displacement and return rates have been identified for these species, the occurrence of secondary project-specific influences such as use of mitigation measures (
e.g.,
bubble curtains, acoustic deterrent devices (ADDs)) or the manner in which species use the habitat in the project area are likely the driving factors of this variation.
NMFS notes the aforementioned studies from Europe involve installing much smaller piles than Sunrise Wind proposes to install. Therefore, we anticipate noise levels from impact pile driving to be louder. For this reason, we anticipate that the greater distances of displacement observed in harbor porpoise and harbor seals documented in Europe are likely to occur off New York. However, we do not anticipate any greater severity of response due to harbor porpoise and harbor seal habitat use off New York or population level consequences similar to European findings. In many cases, harbor porpoises and harbor seals are resident
to the areas where European wind farms have been constructed. However, off New York, harbor porpoises are transient (with higher abundances in winter when impact pile driving would not occur) and a very small percentage of the large harbor seal population are only seasonally present with no rookeries established. In summary, we anticipate that harbor porpoise and harbor seals will likely respond to pile driving by moving several kilometers away from the source but return to typical habitat use patterns when pile driving ceases. As previously noted, the literature on marine mammal responses to offshore wind farms is limited to species which are known to be more behaviorally sensitive to auditory stimuli than the other species that occur in the project area. Therefore, the documented behavioral responses of harbor porpoises and harbor seals to pile driving in Europe should be considered as a worst-case scenario in terms of the potential responses among all marine mammals to offshore pile driving, and these responses cannot reliably predict the responses that will occur in other marine mammal species.
Some avoidance behavior of other marine mammal species has been documented to be dependent on distance from the source in response to playbacks. As described above, DeRuiter
et al.
(2013) noted that distance from a sound source may moderate marine mammal reactions in their study of Cuvier's beaked whales (an acoustically sensitive species), which showed the whales swimming rapidly and silently away when a sonar signal was 3.4-9.5 km away while showing no such reaction to the same signal when the signal was 118 km away even though the received levels were similar. Tyack
et al.
(1983) conducted playback studies of Surveillance Towed Array Sensor System (SURTASS) low frequency active (LFA) sonar in a gray whale migratory corridor off California. Similar to North Atlantic right whales, gray whales migrate close to shore (approximately +2 kms) and are low frequency hearing specialists. The LFA sonar source was placed within the gray whale migratory corridor (approximately 2 km offshore) and offshore of most, but not all, migrating whales (approximately 4 km offshore). These locations influenced received levels and distance to the source. For the inshore playbacks, not unexpectedly, the louder the source level of the playback (
i.e.,
the louder the received level), whale avoided the source at greater distances. Specifically, when the source level was 170 dB rms and 178 dB rms, whales avoided the inshore source at ranges of several hundred meters, similar to avoidance responses reported by Malme
et al.
(1983, 1984). Whales exposed to source levels of 185 dB rms demonstrated avoidance levels at ranges of +1 km. Responses to the offshore source broadcasting at source levels of 185 and 200 dB, avoidance responses were greatly reduced. While there was observed deflection from course, in no case did a whale abandon its migratory behavior.
The signal context of the noise exposure has been shown to play an important role in avoidance responses. In the 2007-2008 Bahamas study, playback sounds of a potential predator—a killer whale—resulted in a similar but more pronounced reaction in beaked whales (an acoustically sensitive species), which included longer inter-dive intervals and a sustained straight-line departure of more than 20 km from the area (Boyd
et al.,
2008; Southall
et al.,
2009; Tyack
et al.,
2011). Sunrise Wind does not anticipate, and NMFS is not proposing to authorize, take of beaked whales and, moreover, the sounds produced by Sunrise Wind do not have signal characteristics similar to predators. Therefore, we would not expect such extreme reactions to occur. Southall
et al.
2011 found that blue whales had a different response to sonar exposure depending on behavioral state, more pronounced when deep feeding/travel modes than when engaged in surface feeding.
One consequence of behavioral avoidance results in the altered energetic expenditure of marine mammals because energy is required to move and avoid surface vessels or the sound field associated with active sonar (Frid and Dill, 2002). Most animals can avoid that energetic cost by swimming away at slow speeds or speeds that minimize the cost of transport (Miksis-Olds, 2006), as has been demonstrated in Florida manatees (Miksis-Olds, 2006).
Those energetic costs increase, however, when animals shift from a resting state, which is designed to conserve an animal's energy, to an active state that consumes energy the animal would have conserved had it not been disturbed. Marine mammals that have been disturbed by anthropogenic noise and vessel approaches are commonly reported to shift from resting to active behavioral states, which would imply that they incur an energy cost.
Forney
et al.
(2017) detailed the potential effects of noise on marine mammal populations with high site fidelity, including displacement and auditory masking, noting that a lack of observed response does not imply absence of fitness costs and that apparent tolerance of disturbance may have population-level impacts that are less obvious and difficult to document. Avoidance of overlap between disturbing noise and areas and/or times of particular importance for sensitive species may be critical to avoiding population-level impacts because (particularly for animals with high site fidelity) there may be a strong motivation to remain in the area despite negative impacts. Forney
et al.
(2017) stated that, for these animals, remaining in a disturbed area may reflect a lack of alternatives rather than a lack of effects.
Flight Response
A flight response is a dramatic change in normal movement to a directed and rapid movement away from the perceived location of a sound source. The flight response differs from other avoidance responses in the intensity of the response (
e.g.,
directed movement, rate of travel). Relatively little information on flight responses of marine mammals to anthropogenic signals exist, although observations of flight responses to the presence of predators have occurred (Connor and Heithaus, 1996; Frid and Dill, 2002). The result of a flight response could range from brief, temporary exertion and displacement from the area where the signal provokes flight to, in extreme cases, beaked whale strandings (Cox
et al.,
2006; D'Amico
et al.,
2009). However, it should be noted that response to a perceived predator does not necessarily invoke flight (Ford and Reeves, 2008), and whether individuals are solitary or in groups may influence the response. Flight responses of marine mammals have been documented in response to mobile high intensity active sonar (
e.g.,
Tyack
et al.,
2011; DeRuiter
et al.,
2013; Wensveen
et al.,
2019), and more severe responses have been documented when sources ar
This text is long and has been trimmed here. Open the source document for the complete record.
This is a copy of a public record, reproduced as it was published. It is not legal advice, and it may not be the version a court would rely on. Check the official source before you cite it.