2024-20541. Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Phase 2 Construction of the Vineyard Wind 1 Offshore Wind Project off Massachusetts

Table 1—Marine Mammal Species That May Occur in the LIA and Be Taken by Harassment

Common name a	Scientific name	Stock	ESA/ MMPA status; strategic (Y/N) b	Stock abundance (CV, N min, most recent abundance survey) c	PBR	Annual M/SI d
Order Artiodactyla—Cetacea—Mysticeti (baleen whales)
Family Balaenidae:
North Atlantic right whale	Eubalaena glacialis	Western Atlantic	E, D, Y	340 (0; 337; 2021) e	0.7	f  27.2
Family Balaenopteridae (rorquals):
Fin whale	Balaenoptera physalus	Western North Atlantic	E, D, Y	6,802 (0.24, 5,573, 2021)	11	2.05
Sei whale	Balaenoptera borealis	Nova Scotia	E, D, Y	6,292 (1.02, 3098, 2021)	6.2	0.6
Minke whale	Balaenoptera acutorostrata	Canadian Eastern Coastal	-, -, N	21,968 (0.31, 17,002, 2021)	170	9.4
Humpback whale	Megaptera novaeangliae	Gulf of Maine	-, -, Y	1,396 (0, 1,380, 2016)	22	12.15
Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
Family Physeteridae:
Sperm whale	Physeter macrocephalus	North Atlantic	E, D, Y	5,895 (0.29, 4,639, 2021)	9.28	0.2
Family Delphinidae:
Long-finned pilot whale	Globicephala melas	Western North Atlantic	-, -, N	39,215 (0.3, 30,627, 2021)	306	5.7
Bottlenose dolphin	Tursiops truncatus	Western North Atlantic Offshore	-, -, N	64,587 (0.24, 52,801, 2021) g	507	28
Common dolphin	Delphinus delphis	Western North Atlantic	-, -, N	93,100 (0.56, 59,897, 2021)	1,452	414
Risso's dolphin	Grampus griseus	Western North Atlantic	-, -, N	44,067 (0.19, 30,662, 2021)	307	18
Atlantic white-sided dolphin	Lagenorhynchus acutus	Western North Atlantic	-, -, N	93,233 (0.71, 54,443, 2021)	544	28
Family Phocoenidae (porpoises):
Harbor porpoise	Phocoena phocoena	Gulf of Maine/Bay of Fundy	-, -, N	85,765 (0.53, 56,420, 2021)	649	145
Order Carnivora—Pinnipedia
Family Phocidae (earless seals):
Harbor seal	Phoca vitulina	Western North Atlantic	-, -, N	61,336 (0.08, 57,637, 2018)	1,729	339
Gray seal h	Halichoerus grypus	Western North Atlantic	-, -, N	27,911 (0.20, 23,924, 2021)	1,512	4,570
a  Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy ( https://marinemammalscience.org/​science-and-publications/​list-marine-mammal-species-subspecies/​; Committee on Taxonomy (2023)).
b  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.
c  NMFS 2022 marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/​national/​marine-mammal-protection/​marine-mammal-stock-assessments. CV is the coefficient of variation; N min is the minimum estimate of stock abundance.
d  These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined ( e.g., commercial fisheries, ship strike).
e  The draft 2023 SAR includes an estimated population (N best 340) based on sighting history through December 2021 (89 FR 5495, January 29, 2024). In October 2023, NMFS released a technical report identifying that the North Atlantic right whale population size based on sighting history through 2022 was 356 whales, with a 95 percent credible interval ranging from 346 to 363 (Linden, 2023).
f  Total annual average observed North Atlantic right whale mortality during the period 2017-2021 was 7.1 animals and annual average observed fishery mortality was 4.6 animals. Numbers presented in this table (27.2 total mortality and 17.6 fishery mortality) are 2016-2020 estimated annual means, accounting for undetected mortality and serious injury.
g  As noted in the draft 2023 SAR (89 FR 5495, January 29, 2024), abundance estimates may include sightings of the coastal form.
h  NMFS' stock abundance estimate (and associated PBR value) applies to the U.S. population only. Total stock abundance (including animals in Canada) is approximately 394,311. The annual M/SI value given is for the total stock.

( print page 75671)

As indicated above, all 14 species (with 14 managed stocks) in table 1 temporally and spatially co-occur with the activity to the degree that take is expected to occur. The following species are not expected to occur in the LIA due to their known distributions, preferred habitats, and/or known temporal and spatial occurrences: the blue whale ( Balaenoptera musculus), northern bottlenose whale ( Hyperoodon ampullatus), false killer whale ( Pseudorca crassidens), pygmy killer whale ( Feresa attenuata), melon-headed whale ( Peponocephala electra), dwarf and pygmy sperm whales ( Kogia spp.), killer whale ( Orcinus orca), Cuvier's beaked whale ( Ziphius cavirostris), four species of Mesoplodont whale ( Mesoplodon densitostris, M. europaeus,M. mirus, and M. bidens), Fraser's dolphin ( Lagenodelphis hosei), Clymene dolphin ( Stenella clymene), spinner dolphin ( Stenella longirostris), rough-toothed dolphin ( Steno bredanensis), Atlantic spotted dolphin ( Stenella frontalis), pantropical spotted dolphin ( Stenella attenuata), short-finned pilot whale ( Globicephala macrorhynchus), striped dolphin ( Stenella coeruleoalba), white-beaked dolphin ( Lagenorhynchus albirostris), and hooded seal ( Crysophora cristata). None of these species were observed during the 2023 construction season or during previous site assessment/characterization surveys (Vineyard Wind 2018, 2019, 2023a-f). Due to the lack of sightings of these species in the MA WEA (Kenney and Vigness-Raposa, 2010; ESS Group Inc., 2016; Kraus et al., 2016; Vineyard Wind, 2018; 2019; O'Brien et al., 2020; 2021; 2022; 2023; EPI Group, 2021; Palka et al., 2017; 2021; RPS, 2022; Vineyard Wind, 2023a-f; Hayes et al., 2023) as well as documented habitat preferences and distributions, we have determined that each of these species will not be considered further. Furthermore, the northern limit of the northern migratory coastal stock of the common bottlenose dolphin ( Tursiops truncatus) does not extend as far north as the LIA. Thus, take is only authorized for the offshore stock which may occur within the LIA. Although harp seals ( Pagophilus groenlandicus) are expected to occur within the WDA, no harp seals were observed by PSOs during the Vineyard Wind 1 site characterization surveys (2016, 2018-2021; ESS Group Inc., 2016; Vineyard Wind 2018; 2019) nor during the 2023 construction campaign (Vineyard Wind, 2023a-f). Thus, Vineyard Wind 1 did not request, and NMFS is not authorizing, take for this species.

A detailed description of the species likely to be affected by the Project, including brief introductions to the species and relevant stocks as well as available information regarding population trends and threats, and information regarding local occurrence, were provided in the proposed IHA notice (89 FR 31008, April 23, 2024). Other than UME updates, we are not aware of any changes in the status of the species and stocks listed in table 1; therefore, detailed descriptions are not provided here. Please refer to the proposed IHA notice for these descriptions (89 FR 31008, April 23, 2024). Please also refer to NMFS' website ( https://www.fisheries.noaa.gov/​find-species) for generalized species accounts.

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

North Atlantic Right Whale

As described in the proposed IHA notice, elevated North Atlantic right whale mortalities have occurred since June 7, 2017, along the U.S. and Canadian coast, with the leading category for the cause of death for this UME determined to be “human interaction,” specifically from entanglements or vessel strikes. Since publication of the proposed IHA, the number of animals considered part of the UME has increased. As of September 5, 2024, there have been 40 confirmed mortalities (dead, stranded, or floaters), 1 pending mortalities, and 35 seriously injured free-swimming whales for a total of 76 whales. The UME also considers animals with sublethal injury or illness (called “morbidity”; n=66) bringing the total number of whales in the UME to 142. More information about the North Atlantic right whale UME is available online at: https://www.fisheries.noaa.gov/​national/​marine-life-distress/​active-and-closed-unusual-mortality-events.

Humpback Whale

Since January 2016, elevated humpback whale mortalities have occurred along the Atlantic coast from Maine to Florida. This event was declared a UME in April 2017. Partial or full necropsy examinations have been conducted on approximately half of the known cases. Since publication of the proposed IHA, the number of animals considered part of the UME has increased to 227 total mortalities (as of September 5, 2024). More information is available at: https://www.fisheries.noaa.gov/​national/​marine-life-distress/​active-and-closed-unusual-mortality-events.

Minke Whale

Since January 2017, a UME has been declared based on elevated minke whale mortalities detected along the Atlantic coast from Maine through South Carolina. As of September 5, 2024, a total of 174 minke whales have stranded during this UME. Full or partial necropsy examinations were conducted on more than 60 percent of the whales. Preliminary findings have shown evidence of human interactions or infectious disease in several of the whales, but these findings are not consistent across all of the whales examined, so more research is needed. More information is available at: https://www.fisheries.noaa.gov/​national/​marine-life-distress/​2017-2024-minke-whale-unusual-mortality-event-along-atlantic-coast.

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. 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, 2019a) recommended that marine mammals be divided into hearing groups based on directly measured (behavioral or auditory evoked potential techniques) or estimated hearing ranges (behavioral response data, anatomical modeling, etc.). Subsequently, NMFS (2018) described generalized hearing ranges for these marine mammal hearing groups. Generalized hearing ranges were chosen based on the approximately 65 dB threshold from the normalized composite audiograms, with the exception for lower limits for low-frequency cetaceans where the lower bound was deemed to be biologically implausible and the lower bound from Southall et al. (2007) retained. Marine mammal hearing groups and their associated hearing ranges are provided in table 2. ( print page 75672)

Table 2—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.
Otariid pinnipeds (OW) (underwater) (sea lions and fur seals)	60 Hz to 39 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 et al., 2013).

For more detail concerning these groups and associated frequency ranges, please see NMFS (2018) for a review of available information.

Potential Effects of Specified Activities on Marine Mammals and Their Habitat

Exposure to underwater noise from the specified activities has the potential to result in Level A harassment or Level B harassment of marine mammals in the specific geographic region, but no serious injury or mortality. The proposed IHA Federal Register notice (89 FR 31008, April 23, 2024) included a discussion of the effects of anthropogenic noise on marine mammals and the potential effects of underwater noise from the Project's specified activities on marine mammals and their habitat. While some new literature regarding marine mammal distribution and habitat use has been published since publication of the proposed IHA ( e.g., Bellman et al., 2023; Holdman et al., 2023, Meyer-Gutbrod et al., 2023; Roberts et al., 2024; Thorne and Wiley, 2024), there is no new information that NMFS is aware of that changes the analysis in the proposed IHA notice. We provide a summary of these papers below.

Bellmann et al. (2023) collected 27 operational noise measurements across 24 offshore wind farms consisting of 16 different WTG types of powers ranging from 2.3 to 8 mega watts (MW). It should be noted that the results from Holme et al. (2023) are based on a subset of these data. Similar to Holme et al. (2023), Bellmann et al. (2023) note that no relationship between nominal WTG power and operational noise was observed, in contrast with the linear models used by Tougaard et al. (2020) and Stöber and Thomsen (2021). It is theorized that this is related to gearless and more modern WTGs measured as well as increased size and weight reducing transmission of vibrations. With regard to the extent of operational noise levels, Bellmann et al. (2023) concluded that tonal components of the operational noise are clearly observable at a range of 100 meters, but typically are not resolvable within the prevailing ambient noise at a range of 5 km. However, Bellmann et al. (2023) also comment that these measurements were taken within the first year of operation, and that previous experience indicates noise levels will change significantly over time, likely due to wear and tear in gearbox WTGs, but that it is not clear at this time if these changes will also be present in direct-drive systems.

Holdman et al. (2023) studied harbor porpoise habitats in the Gulf of Maine (GOM) and Southern New England waters providing baseline data on the occurrence and foraging activity of porpoises from 2020 to 2022. Harbor porpoises were present year-round in the GOM with peak detections in the summer and fall. The observed seasonal pattern of harbor porpoise occurrence in this study is consistent with prior information on the general distribution of the GOM/Bay of Fundy stock (Wingfield et al., 2017; Hayes et al., 2022). In line with previously reported distribution patterns, harbor porpoise occurrence in Southern New England was high in fall, winter and spring, but porpoises were largely absent in the summer. Results from generalized additive models suggest that time of year, hour of day, lunar illumination, and temperature are significant contributors to harbor porpoise presence (detection mainly through echolocation clicks) and/or foraging effort. This study emphasized the importance of early identification of important harbor porpoise habitat to mitigate impacts and monitor change in the event of overlap between these habitats and areas proposed for offshore wind development.

Meyer-Gutbrod et al. (2023) studied North Atlantic right whale sightings from 1990-2018 to examine patterns in monthly habitat use in 12 high-use areas to broadly characterize new seasonal habitat-use patterns across the core North Atlantic right whale range. As North Atlantic right whale foraging habitat selection is driven by complex spatial and temporal patterns ( e.g., prey abundance), abundances of Calanus finmarchicus (a species of copepod and a component of the zooplankton found in the northern Atlantic Ocean) and Calanus hyperboreus (species of copepod found in the Arctic Ocean and northern Atlantic Ocean) were also analyzed for decadal variations in the North Atlantic right whale foraging habitats. The research found that in comparison to the 2000s, the 1990s and the 2010s were similar in that North Atlantic right whale sightings ( i.e., Sightings Per Unit Effort (SPUE)) declined in the foraging habitats of the Gulf of Maine and Scotian Shelf during the seasons when abundance of C. finmarchicus was relatively low (spring, summer, fall). The drop in sightings is associated with extended duration of habitat use by North Atlantic right whales in Cape Cod Bay into the late spring and increased use of Southern New England waters and the Gulf of St. Lawrence in the spring and summer in the 2010s. Summertime declines in the 2010s for copepod abundances in the traditional foraging habitat ( e.g., Gulf of Maine) indicate that the increased use of the Gulf of St. Lawrence in more recent years is driven by a decline in prey in traditional foraging habitats rather than by an increase in prey in the new foraging habitat. Overall, while some patterns in seasonal habitat use remained consistent across all three decades, including the winter migration to the Southeast U.S. calving ground ( print page 75673) and early spring foraging in Cape Cod Bay, there were notable differences in the seasonality and persistence of North Atlantic right whales in some foraging habitats across the study period which indicate that the North Atlantic right whale distribution patterns are shifting.

In 2022, the Duke University Marine Geospatial Ecology Laboratory provided updated habitat-based marine mammal density models for the U.S. Atlantic (Roberts et al., 2016; Roberts et al., 2023). The take estimate analysis for the Vineyard Wind 1 IHA incorporates these density models into methodology for estimating take from foundation installation (89 FR 504, January 4, 2024). Recently, North Atlantic right whale density model results were evaluated using independently collected passive acoustic monitoring (PAM data) (Roberts et al., 2024). Positive correlations between North Atlantic right whale densities and acoustic detection rates indicated concurrence between visual and acoustic observations of North Atlantic right whales. Results of this study also further quantify the North Atlantic right whale distribution shifts that occurred in 2010.

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

Overall, there is no new scientific information regarding the general anticipated effects of offshore wind construction on marine mammals and their habitat that was not discussed in the proposed IHA. The information and analysis regarding the potential effects on marine mammals and their habitat included in the proposed IHA Federal Register notice is referenced and used for this final IHA notice and is not repeated here; please refer to the proposed IHA Federal Register notice (89 FR 31008, April 23, 2024).

Globally, there are more than 341,000 operating WTGs (Global Wind Energy Council). Turbine failures are known to occur but are considered rare events (Katsaprakakis et al., 2021, DOE, 2024a). For example, fewer than 40 incidents were identified in the modern fleet of more than 40,000 onshore turbines installed in the United States as of 2014 (DOE, 2024b). In 2022, the total global capacity of offshore wind reached 59,009 MW from 292 operating projects and over 11,900 operating wind turbines in 2022 (DOE, 2023), and a review of the relevant literature and media reports indicate blade failure among this cohort of turbines continues to be rare, consistent with industry performance in onshore wind turbines. On July 13, 2024, however, a blade on one of the WTGs at Vineyard Wind 1 was damaged during the “warm up” phase of operations, causing a portion of the blade, primarily composed of fiberglass, to fall into the water. In cooperation with Vineyard Wind 1, GE Vernova, the blade manufacturer, initiated debris recovery efforts and an investigation. Following this blade failure incident, the Bureau of Safety and Environmental Enforcement (BSEE), Department of Interior, issued a Suspension Order on July 17, 2024 ( https://www.bsee.gov/​newsroom/​latest-news/​statements-and-releases/​press-releases/​bsee-statement-on-vineyard-wind) and an additional Order for clarification on July 26, 2024 ( https://www.bsee.gov/​newsroom/​latest-news/​statements-and-releases/​press-releases/​bsee-issues-new-order-to-vineyard-wind), which suspends power production and any further wind turbine generator construction until the suspension is lifted. GE Vernova has preliminarily identified a defect in the manufacturing process, specifically insufficient bonding, of this particular blade that the quality assurance program should have identified. On August 9, 2024, Vineyard Wind and GE Vernova released an action plan that outlines the steps necessary to remove the remainder of the damaged blade, continue debris cleanup response efforts, and resume turbine installation and operations of the project. The plan specifies that no blades will be installed or used in operation until each is inspected. In addition, GE has developed and will implement real-time monitoring technology to monitor blades during operations to avoid this type of incident from occurring in the future.

As noted above, wind turbine failure is considered rare, and NMFS still considers the likelihood that blade failure would occur pursuant to Vineyard Wind 1's specified activity during the effective period of the IHA so low as to be discountable. Furthermore, GE Vernova's quality assurance program will complete thorough inspections on the remaining blades to be installed to ensure additional blade malfunction incidents do not occur. Vineyard Wind 1 did not request, NMFS does not anticipate, and NMFS has not authorized, take of marine mammals incidental to a turbine blade failure and, therefore the topic is not discussed further.

Estimated Take of Marine Mammals

This section provides an estimate of the number of incidental takes authorized through this IHA, which will inform NMFS' consideration of “small numbers” and the negligible impact determinations (impacts on subsistence uses is not relevant here).

Harassment is the only type of take expected to result from these activities. Except with respect to certain activities not pertinent here, section 3(18) of the MMPA defines “harassment” as any act of pursuit, torment, or annoyance, which (i) has the potential to injure a marine mammal or marine mammal stock in the wild (Level A harassment); or (ii) has the potential to disturb a marine mammal or marine mammal stock in the wild by causing disruption of behavioral patterns, including, but not limited to, migration, breathing, nursing, breeding, feeding, or sheltering (Level B harassment).

Authorized takes would primarily be by Level B harassment, as noise from pile driving has the potential to result in disruption of marine mammal behavioral patterns. Impacts such as masking and TTS can contribute to the disruption of behavioral patterns and are accounted for within those authorized takes. There is also some potential for high frequency species (harbor porpoise) and phocids (harbor ( print page 75674) seal and gray seal) to experience a limited amount of auditory injury (PTS; Level A harassment) primarily because predicted auditory injury zones are large enough and these species are cryptic enough that the potential for PTS cannot be fully discounted or mitigated. For mysticetes, the Level A harassment ER95_percent ranges are also large (0.043 km to 3.191 km); however, the extensive marine mammal mitigation and monitoring planned by Vineyard Wind 1 and required by NMFS, as well as natural avoidance behaviors is expected to reduce the potential for PTS to discountable levels. Nevertheless, Vineyard Wind 1 has requested, and NMFS has authorized a small amount of Level A harassment incidental to installing piles (table 11). Auditory injury is unlikely to occur for mid-frequency species as thresholds are higher and PTS zones are very close to the pile, such that PTS is unlikely to occur. While NMFS has authorized Level A harassment and Level B harassment, the planned mitigation and monitoring measures are expected to avoid or minimize overall the taking to the extent practicable (see Mitigation and Monitoring and Reporting).

As described previously, no serious injury or mortality is anticipated or authorized incidental to the specified activity. Even without mitigation, pile driving activities are unlikely to directly cause marine mammal mortality or serious injury. There is no documented case wherein pile driving resulted in marine mammal mortality or stranding and the scientific literature demonstrates that the most likely behavioral response to pile driving (or similar stimulus source) is avoidance and temporary cessation of behaviors such as foraging or socialization (see Avoidance and Displacement in Potential Effects of Specified Activities on Marine Mammals and Their Habitat section of the proposed IHA Federal Register notice (89 FR 31008, April 23, 2024). While in general there is a low probability that mortality or serious injury of marine mammals could occur from vessel strikes, the mitigation and monitoring measures contained within this IHA are expected to avoid vessel strikes (see Mitigation section). No other activities have the potential to result in mortality or serious injury.

For acoustic impacts, we estimate take by considering: (1) acoustic thresholds above which NMFS believes the best available science indicates marine mammals will be behaviorally harassed or incur some degree of permanent hearing impairment; (2) the area or volume of water that will be ensonified above these levels in a day; (3) the density or occurrence of marine mammals within these ensonified areas; and (4) the number of days of activities. We note that while these factors can contribute to a basic calculation to provide an initial prediction of potential takes, additional information that can qualitatively inform take estimates is also sometimes available ( e.g., previous monitoring results or average group size). Below, we describe the factors considered here in more detail and present the authorized take estimates.

As described below, there are multiple methods available to estimate the density or number of a given species in the area appropriate to inform the take estimate. For each species and activity, the largest value resulting from the three take estimation methods described below ( i.e., density-based, PSO-based, or mean group size) was carried forward as the amount of take authorized by Level B harassment. The amount of take authorized by Level A harassment reflects the density-based exposure estimates and, for some species and activities, consideration of other data such as mean group size.

Below, we describe NMFS' acoustic thresholds, acoustic and exposure modeling methodologies, marine mammal density calculation methodology, occurrence information, and the modeling and methodologies applied to estimate take for the Project's planned construction activities. NMFS considered all information and analysis presented by Vineyard Wind, as well as all other applicable information and, based on the best available science, concurs that the estimates of the types and amounts of take for each species and stock are reasonable, and has authorized the amount requested. NMFS notes the take estimates described herein for foundation installation can be considered conservative because the estimates do not reflect the implementation of clearance and shutdown zones for any marine mammal species or stock.

Acoustic Thresholds

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

Level B Harassment —Though significantly driven by received level, the onset of behavioral disturbance from anthropogenic noise exposure is also informed to varying degrees by other factors related to the source or exposure context ( e.g., frequency, predictability, duty cycle, duration of the exposure, signal-to-noise ratio, distance to the source, ambient noise, and the receiving animal's hearing, motivation, experience, demography, behavior at time of exposure, life stage, depth) and can be difficult to predict ( e.g., Southall et al., 2007, 2021, Ellison et al., 2012). Based on what the available science indicates and the practical need to use a threshold based on a metric that is both predictable and measurable for most activities, NMFS typically uses a generalized acoustic threshold based on received level to estimate the onset of behavioral harassment.

NMFS generally predicts that marine mammals are likely to be taken in a manner considered to be Level B harassment when exposed to underwater anthropogenic noise above RMS SPL of 120 dB (referenced to 1 micropascal (re 1 μPa)) for continuous ( e.g., vibratory pile driving, drilling) and above RMS SPL 160 dB re 1 μPa for non-explosive impulsive ( e.g., seismic airguns) or intermittent ( e.g., scientific sonar) sources. Generally speaking, Level B harassment take estimates based on these thresholds are expected to include any likely takes by TTS as, in most cases the likelihood of TTS occurs at closer distances from the source. TTS of a sufficient degree can manifest as behavioral harassment, as reduced hearing sensitivity and the potential reduced opportunities to detect important signals (conspecific communication, predators, prey) may result in changes in behavior patterns that would not otherwise occur.

The Project's planned construction activities include the use of impulsive sources ( e.g., impact pile driving), and therefore the 160-dB re 1 μPa (rms) threshold is applicable to our analysis.

Level A Harassment —NMFS' Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0, Technical Guidance) (NMFS, 2018) identifies dual criteria to assess auditory injury (Level A harassment) to five different marine mammal groups (based on hearing sensitivity) as a result of exposure to noise from two different types of sources (impulsive or non-impulsive). As dual metrics, NMFS considers onset of PTS (Level A harassment) to have occurred when either one of the two metrics is exceeded ( i.e., metric resulting in the largest isopleth). As described above, the Vineyard Wind 1 planned activities include the use of impulsive sources. ( print page 75675) NMFS' thresholds identifying the onset of PTS are provided in table 3. The references, analysis, and methodology used in the development of the thresholds are described in NMFS' 2018 Technical Guidance, which may be accessed at: https://www.fisheries.noaa.gov/​national/​marine-mammal-protection/​marine-mammal-acoustic-technical-guidance.

Table 3—Permanent Threshold Shift (PTS) Onset Thresholds

[NMFS, 2018]

Hearing group	PTS onset thresholds * (received level)
	Impulsive	Non-impulsive
Low-Frequency (LF) Cetaceans	L p,0-pk,flat : 219 dB; L E,p,LF,24h : 183 dB	L E,p,LF,24h : 199 dB.
Mid-Frequency (MF) Cetaceans	L p,0-pk,flat : 230 dB; L E,p,MF,24h : 185 dB	L E,p MF,24h : 198 dB.
High-Frequency (HF) Cetaceans	L p,0-pk,flat : 202 dB; L E,p,HF,24h : 155 dB	L E,p,HF,24h : 173 dB.
Phocid Pinnipeds (PW) (Underwater)	L p,0-pk,flat : 218 dB; L E,p,PW,24h : 185 dB	L E,p,PW,24h : 201 dB.
Otariid Pinnipeds (OW) (Underwater)	L p,0-pk,flat : 232 dB; L E,p,OW,24h : 203 dB	L E,p,OW,24h : 219 dB.
* Dual metric thresholds for impulsive sounds: Use whichever results in the largest isopleth for calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level thresholds associated with impulsive sounds, these thresholds are recommended for consideration.
Note: Peak sound pressure level (L p,0-pk ) has a reference value of 1 µPa, and weighted cumulative sound exposure level (L E,p ) has a reference value of 1µPa2 s. In this Table, thresholds are abbreviated to be more reflective of International Organization for Standardization standards (ISO, 2017). The subscript “flat” is being included to indicate peak sound pressure are flat weighted or unweighted within the generalized hearing range of marine mammals ( i.e., 7 Hz to 160 kHz). The subscript associated with cumulative sound exposure level thresholds indicates the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is 24 hours. The weighted cumulative sound exposure level thresholds could be exceeded in a multitude of ways ( i.e., varying exposure levels and durations, duty cycle). When possible, it is valuable for action proponents to indicate the conditions under which these thresholds will be exceeded.

Below, we describe the assumptions and methodologies used to estimate take, in consideration of acoustic thresholds and appropriate marine mammals density and occurrence information, for WTG monopile installation. Resulting distances to thresholds, densities and occurrence ( i.e., PSO sightings, group size) data used, exposure estimates (as relevant to the analysis), and activity-specific take estimates can be found below.

Acoustic and Exposure Modeling

During the 2023 Vineyard Wind 1 pile installation activities, Vineyard Wind 1 conducted a SFV study to compare with model results of the 2018 modeling (Küsel et al., 2024). The SFV study included acoustic monitoring of the impact installation of 12 monopile foundations from June 6 through September 7, 2023. Five of the 12 acoustically monitored monopiles were determined to be representative of the noise attenuation system (NAS) configuration and maintenance schedule that would be proposed for the remaining 15 monopiles to be installed in 2024. These five representative monopiles (piles 7, 8, 10, 11, and 12 in the Vineyard Wind 1 SFV Monitoring Report) were monitored using a DBBC and Hydrosound Damper System (HSD), which Vineyard Wind 1 will be required to use for use as the noise attenuation system setup for the remaining 15 monopiles. Vineyard Wind 1 also followed an enhanced bubble curtain maintenance schedule for these 5 monopiles; this maintenance schedule will be used for the remaining 15 monopiles to be installed under this IHA (see the Vineyard Wind 1 Enhanced Big Bubble Curtain (BBC) Technical Memo). Peak (pk), SEL, and RMS SPL received distances for each acoustically monitored pile are reported in the VW1 SFV Final Report Appendix A (Küsel et al., 2024) For additional details on how acoustic ranges were derived from SFV measurements, see the VW1 SFV Final Report sections 2.3 and 3.3 (Küsel et al., 2024). JASCO modeled a maximum range to the Level A harassment threshold of 3.191 km (1.99 mi) with 6 dB attenuation (for low-frequency cetaceans) (Küsel et al., 2024).

In addition to the 15 piles being installed under the same noise attenuation scenario as the 5 aforementioned representative piles, they are also anticipated to be installed under similar pile driving specifications and in a similar acoustic environment. Table 4 describes the key piling assumptions and planned impact pile driving schedule for 2024. These assumptions and schedule are based upon the 2023 piling and hammer energy schedule for installing monopiles. Vineyard Wind 1 expects installation of the 15 remaining piles will necessitate similar operations. Further, as described in detail in section 6.1 of the Vineyard Wind 1 application, the water depth and bottom type are similar throughout the Lease Area and therefore sound propagation in the LIA is not expected to differ from where the SFV data were collected in 2023.

Table 4—Key Piling Assumptions and Hammer Energy Schedule for Monopile Installation

Pile type	Project component	Max hammer energy rating (kJ)	Number of hammer strikes	Max piling time duration per pile (min)	Number piles/day
9.6-m monopile	WTG	4,000	2,884-4,329 (average 3,463) a	117	1
a  The number of hammer strikes represents the range of strikes needed to install the 12 monopiles for which SFV was conducted in 2023.

Vineyard Wind 1 compared the acoustic ranges to the Level A harassment and Level B harassment thresholds derived from the 2018 acoustic modeling (Pyć et al., 2018) to the maximum ranges with absorption for the five representative monopiles acoustically monitored in 2023. They applied the greater results to the ( print page 75676) analysis in their application and NMFS has included that approach in this IHA. The maximum measured range to PTS thresholds of the five representative monopiles was less than the maximum 2018 modeled ranges for all hearing groups assuming 6 dB attenuation (table 5) (with the exception of high-frequency cetaceans, although Vineyard Wind 1 attributes this extended range to non-piling noise (Vineyard Wind 1, 2023)). Therefore, Vineyard Wind 1 based the expected distance to the Level A harassment threshold and associated estimated take analysis on the 2018 modeled data.

Table 5—Modeled and Measured Ranges to SEL _cum PTS Thresholds for Marine Mammal Hearing Groups

Marine mammal hearing group	Modeled range to SEL cum PTS threshold (km) a	Measured maximum range to SEL cum PTS threshold (km) b
Low-frequency cetaceans	3.191	2.370
Mid-frequency cetaceans	0.043	0.010
High-frequency cetaceans	0.071	0.200
Phocid pinnipeds	0.153	0.100
a  Based upon modeling conducted for the 2023 IHA (Pyć et al., 2018).
b  Based upon the five representative monopiles from the Vineyard Wind 1 2023 construction campaign (Küsel et al., 2024).

The maximum range with absorption to the Level B harassment threshold for acoustically monitored piles was 5.72 km (3.6 mi) (pile 13, AU-38; Küsel et al., 2024), which was greater than the 2018 modeled distance to the Level B harassment threshold of 4.1 km (2.5 mi) (Pyć et al. 2018). Therefore, Vineyard Wind 1 based the expected distance to the Level B harassment threshold for this IHA and associated estimated take analysis on the 5.72 km acoustically monitored distance.

In 2018, Vineyard Wind 1 conducted animat modeling to estimate take, by Level A harassment (PTS), incidental to the project. In order to best evaluate the SEL_cum harassment thresholds for PTS, it is necessary to consider animal movement, as the results are based on how sound moves through the environment between the source and the receiver. Applying animal movement and behavior within the modeled noise fields provides the exposure range, which allows for a more realistic indication of the distances at which PTS acoustic thresholds are reached that considers the accumulation of sound over different durations (note that in all cases the distance to the peak threshold is less than the SEL-based threshold). As described above, Vineyard Wind 1 based the Level A harassment estimated take analysis on the modeled Level A harassment acoustic ranges and therefore appropriately used the results of the JASCO's Animal Simulation Model Including Noise Exposure (JASMINE) animal movement modeling conducted for the 2023 IHA (86 FR 33810, June 25, 2021). Sound exposure models like JASMINE use simulated animals (also known as “animats”) to forecast behaviors of animals in new situations and locations based upon previously documented behaviors of those animals. The predicted 3D sound fields ( i.e., the output of the acoustic modeling process described earlier) are sampled by animats using movement rules derived from animal observations. The output of the simulation is the exposure history for each animat within the simulation. The precise locations of animats and their pathways are not known prior to a project; therefore, a repeated random sampling technique ( i.e., Monte Carlo) is used to estimate exposure probability with many animats and randomized starting positions. The combined exposure history of all animats gives a probability density function of exposure during the Project.

Since the time that the JASMINE animal movement modeling was conducted for the 2023 IHA (86 FR 33810, June 25, 2021), no new behavior data is available that would have changed how animats move in time and space in that model and, therefore, NMFS has determined that the JASMINE outputs from the 2018 modeling effort are reasonable for application here. However, the post processing calculations used more recent density data (table 6). The mean number of modeled animats exposed per day with installation of one 9.6-m monopile were scaled by the maximum monthly density for the LIA (Roberts et al., 2023) for each species (table 6) to estimate the real-world number of animats of each species that could be exposed per day in the LIA. This real-world number of animals was multiplied by the expected number of days of pile installation (15 days) to derive a total take estimate by Level A harassment for each species. The number of potential exposures by Level A harassment was estimated for each species using the following equation:

Density-based exposure estimate_{Level A harassment} = number of animats exposed above the Level A harassment threshold × ((mean maximum monthly density (animals/km² )/modeled 2018 density (animats/km² )) × number of days (15).

To estimate the amount of take by Level B harassment incidental to installing the remaining 15 piles, Vineyard Wind 1 applied a static method ( i.e., did not conduct animal movement modeling). Vineyard Wind 1 calculated the Level B harassment ensonified area using the following equation:

A = x r² ,

where A is equal to the ensonified area and r is equal to the radial distance to the Level B harassment threshold from the pile driving source (r_{Level B harassment} = 5.72 km).

The ensonified area (102.7 km² ) was multiplied by the mean maximum monthly density estimate (table 8) and expected number of days of pile driving (15 days) to determine a density-based take estimate for each species. The number of potential exposures by Level B harassment was estimated for each species using the following equation:

Density-based exposure estimate_{Level B harassment} = ensonified area (km² ) × maximum mean monthly density estimate (animals/km² ) × number of days (15).

Density and Occurrence and Take Estimation

In this section we provide information about marine mammal density, presence, and group dynamics that informed the take calculations for the planned activities. Vineyard Wind applied the 2022 Duke University Marine Geospatial Ecology Laboratory Habitat-based Marine Mammal Density Models for the U.S. Atlantic (Duke ( print page 75677) Model-Roberts et al., 2016; Roberts et al., 2023) to estimate take from foundation installation. The models estimate absolute density (individuals/km² ) by statistically correlating sightings reported on shipboard and aerial surveys with oceanographic conditions. For most marine mammal species, densities are provided on a monthly basis. Where monthly densities are not available ( e.g., pilot whales), annual densities are provided. Moreover, some species are represented as guilds ( e.g., seals (representing Phocidae spp., primarily harbor and gray seals and pilot whales (representing short-finned and long-finned pilot whales))).

The Duke habitat-based density models delineate species' density into 5 * 5 km (3.1 * 3.1 mi) grid cells. Vineyard Wind 1 calculated mean monthly densities by using a 10-km buffered polygon around the remaining WTG foundations to be installed and overlaying this buffered polygon on the density maps. The 10-km buffer defines the area around the LIA used to calculate mean species density. Mean monthly density for each species was determined by calculating the unweighted mean of all 5x5 km grid cells (partially or fully) within the buffered polygon. The unweighted mean refers to using the entire 5 km x 5 km (3.1 mi x 3.1 mi) grid cell for each cell used in the analysis, and was not weighted by the proportion of the cell overlapping with the density perimeter if the entire grid cell was not entirely within the buffer zone polygon. Vineyard Wind 1 calculated densities for each month, except for species for which annual density data only was available ( e.g., long-finned pilot whale). Vineyard Wind 1 used maximum monthly density from June to December for density-based calculations.

The density models (Roberts et al., 2023) provided density for pilot whales and seals as guilds. Based upon habitat and ranging patterns (Hayes et al., 2023), all pilot whales occurring in the LIA are expected to be long-finned pilot whales. Therefore, all pilot whale density estimates are assumed to represent long-finned pilot whales. Seal guild density was divided into species-specific densities based upon the proportions of each species observed by PSOs during 2016 and 2018-2021 site characterizations surveys within SNE (ESS Group, 2016; Vineyard Wind 2018, 2019, 2023a-f). Of the 181 seals identified to species and sighted within the WDA, 162 were gray seals and 19 were harbor seals. The equation below shows how the proportion of each seal species sighted was calculated to compute density for seals.

P_{seal species} = N_{seal species} /Number_{total seals identified}

where P represents density and N represents number of seals.

These calculations resulted in proportions of 0.895 for gray seals and 0.105 for harbor seals. The proportion for each species was then multiplied by the maximum monthly density for the seal guild (table 6) to determine the species-specific densities used in take calculations.

The density models (Roberts et al., 2023) also do not distinguish between bottlenose dolphin stocks and only provide densities for bottlenose dolphins as a species. However, as described above, based upon ranging patterns (Hayes et al., 2023), only the Western North Atlantic offshore stock of bottlenose dolphins is expected to occur in the LIA. Therefore, it is expected that the bottlenose dolphin density estimate is entirely representative of this stock. Maximum mean monthly density estimates and month of the maximum estimate are provided in table 6 below.

Table 6—Maximum Mean Monthly Marine Mammal Density Estimates (Animals per km² ) Considering a 10- km Buffer Around the Limited Installation Area

Species	Maximum mean density	Maximum density month
North Atlantic right whale *	0.0043	December.
Fin whale *	0.0036	July.
Humpback whale	0.0022	June.
Minke whale	0.0180	June.
Sei whale *	0.0008	November.
Sperm whale *	0.0008	September.
Atlantic white-sided dolphin	0.0204	June.
Bottlenose dolphin a	0.008	August.
Common dolphin	0.1467	September.
Long-finned pilot whale b	0.001	N/A.
Risso's dolphin	0.0013	December.
Harbor porpoise	0.0713	December.
Seals (gray and harbor) c	0.1745	May.
Note: * denotes species listed under the Endangered Species Act.
a  Density estimate represents the Northwestern Atlantic offshore stock of bottlenose dolphins.
b  Only annual densities were available for the pilot whale guild.
c  Gray and harbor seals represented as a guild.

For some species, PSO survey and construction data for SNE (ESS Group, 2016; Vineyard Wind, 2018, 2019, 2023a-f) and mean group size data compiled from the AMAPPS (Palka et al., 2017; 2021) indicate that the density-based exposure estimates may be insufficient to account for the number of individuals of a species that may be encountered during the planned activities. Hence, local PSO and AMAPPS data were considered to ensure the potential for take is adequately assessed.

In cases where the density-based Level B harassment exposure estimate for a species was less than the mean group size-based exposure estimate, the take request was increased to the mean group size (in some cases multiple groups were assumed) and rounded to the nearest integer (table 7). For all cetaceans, with the exception of North Atlantic right whales, Vineyard Wind 1 used the mean of the spring, summer, and fall AMAPPS group sizes for each species for the Rhode Island/Massachusetts Wind Energy Area (RI/MA WEA) as shown in tables 2-2, 2-3, and 2-4 in Palka et al. (2021) appendix III. These seasons were selected as they would represent the time period in which pile driving activities would take place. Mean group sizes for cetacean species derived from RI/WEA AMAPPS data is shown below in table 7. ( print page 75678) However, North Atlantic right whale seasonal group sizes for the RI/MA WEA were not available through the AMAPPS dataset (Palka et al., 2021). Vineyard Wind 1 calculated mean group size for North Atlantic right whales using data from the northeast (NE) shipboard surveys as provided in table 6-5 of Palka et al. (2021). Vineyard Wind 1 calculated mean group size by dividing the number of individual right whales sighted (four) by the number of right whale groups (two) (Palka et al., 2021). The NE shipboard surveys were conducted during summer (June 1 through August 31) and fall (September 1 through November 30) seasons (Palka et al., 2021).

For seals, mean group size data was also not available for the RI/MA WEA through AMAPPS (Palka et al., 2021). Vineyard Wind 1 used 2010-2013 AMAPPS NE shipboard and aerial survey at-sea seal sightings for gray and harbor seals, as well as unidentified seal sightings from spring, summer, and fall to calculate mean group size for gray and harbor seals (table 19-1, Palka et al., 2017). To calculate mean group size for seals, Vineyard Wind 1 divided the total number of animals sighted by the total number of sightings. As the majority of the sightings were not identified to species, Vineyard Wind 1 calculated a single group size for all seal species (table 7).

Additional detail regarding the density and occurrence as well as the assumptions and methodology used to estimate take is included below and in section 6.2 of the incidental take authorization (ITA) application. Mean group sizes used in take estimates, where applicable, for all activities are provided in table 7.

Table 7—Mean Marine Mammal Group Sizes Used in Take Estimate Calculations

Species	Mean group size	Source
North Atlantic right whale *	2	Table 6-5 of Palka et al. 2021.
Fin whale *	1.2	Palka et al. 2021.
Humpback whale	1.2	Palka et al. 2021.
Minke whale	1.4	Palka et al. 2021.
Sei whale *	1	Palka et al. 2021.
Sperm whale *	2	Palka et al. 2021.
Atlantic white-sided dolphin	21.7	Palka et al. 2021.
Bottlenose dolphin	11.7	Palka et al. 2021.
Common dolphin	30.8	Palka et al. 2021.
Long-finned pilot whale	12.3	Palka et al. 2021.
Risso's dolphin	1.8	Palka et al. 2021.
Harbor porpoise	2.9	Palka et al. 2021.
Seals (gray and harbor)	1.4	Table 19-1 of Palka et al. 2017.
Note: * denotes species listed under the Endangered Species Act.

Vineyard Wind 1 also looked at PSO survey data (June through October 2023) in the LIA collected during Vineyard Wind 1 construction activities and calculated a daily sighting rate for species to compare with density-based take estimates and average group size estimates from AMAPPS (table 7). The number of animals of each species sighted from all survey vessels with active PSOs was divided by the sum of all PSO monitoring days (77 days) to calculate the mean number of animals of each species sighted (see table 11 in the ITA application). However, for each species, the PSO data-based exposure estimate was less than the density-based exposure estimate (see table 14 in the ITA application) and, therefore, density-based exposure estimates were not adjusted according to PSO data-based exposure estimates.

Here we present the amount of take requested by Vineyard Wind 1 and authorized by NMFS. To estimate take, Vineyard Wind 1 used the pile installation construction schedule shown in table 4, assuming 15 total days of monopile installation. NMFS has reviewed these methods to estimate take and agrees with this approach. The authorized take numbers in table 9 appropriately consider SFV measurements collected in 2023 and represent the maximum amount of take that is reasonably expected to occur.

Table 8—Modeled Level A Harassment and Level B Harassment Acoustic Exposure Estimates

Species	Density-based exposure estimate
	Level A harassment	Level B harassment
North Atlantic right whale * a	0.503	6.6
Fin whale *	0.598	5.5
Humpback whale	1.11	3.4
Minke whale	0.372	27.7
Sei whale *	0.144	1.2
Sperm whale *	0	1.2
Atlantic white-sided dolphin	0	31.4
Bottlenose dolphin	0	12.3
Common dolphin	0	226.0
Long-finned pilot whale	0	1.5
Risso's dolphin	0	2.00
Harbor porpoise	2.758	109.8
Gray Seal	0	240.8
Harbor seal	0.028	28.2
Note: * denotes species listed under the Endangered Species Act.
a  Although modeling shows a very low but non-zero exposure estimate for take by Level A harassment, mitigation measures will be applied to ensure there is no take by Level A harassment of this species.

( print page 75679)

Table 9—Authorized Takes (by Level A Harassment and Level B Harassment)

Species	NMFS stock abundance	Authorized take by Level A harassment	Authorized take by Level B harassment	Total authorized take	Percent of stock abundance
North Atlantic right whale * a	338	0	7	7	2.07
Fin whale *	6,802	1	6	7	0.10
Humpback whale	1,396	2	4	6	0.43
Minke whale	21,968	1	28	29	0.13
Sei whale *	6,292	1	2	3	0.05
Sperm whale *	4,349	0	2	2	0.05
Atlantic white-sided dolphin	93,233	0	32	32	0.03
Bottlenose dolphin	62,851	0	13	13	0.02
Common dolphin  b c	172,974	0	462	462	0.27
Long-finned pilot whale b	39,215	0	13	13	0.03
Risso's dolphin	35,215	0	2	2	0.001
Harbor porpoise	95,543	3	110	113	0.19
Gray Seal	27,300	0	241	241	0.88
Harbor seal	61,336	1	29	30	0.05
Note: * denotes species listed under the Endangered Species Act.
a  Although modeling shows a very low but non-zero exposure estimate for take by Level A harassment, mitigation measures will be applied to ensure there is no take by Level A harassment of this species.
b  Authorized take by Level B harassment adjusted according to mean group size.
c  Authorized take by Level B harassment is based upon the assumption that one group of common dolphins (30.8 dolphins; see table 7) would be encountered per each of the 15 days of pile driving.

Mitigation

In order to issue an IHA under section 101(a)(5)(D) of the MMPA, NMFS must set forth the permissible methods of taking pursuant to the activity, and other means of effecting the least practicable impact on the species or stock and its habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance, and on the availability of the species or stock for taking for certain subsistence uses (latter not applicable for this action). NMFS regulations require applicants for incidental take authorizations to include information about the availability and feasibility (economic and technological) of equipment, methods, and manner of conducting the activity or other means of effecting the least practicable adverse impact upon the affected species or stocks, and their habitat (50 CFR 216.104(a)(11)).

In evaluating how mitigation may or may not be appropriate to effect the least practicable adverse impact on species or stocks and their habitat, as well as subsistence uses where applicable, NMFS considers two primary factors:

(1) The manner in which, and the degree to which, the successful implementation of the measure(s) is expected to reduce impacts to marine mammals, marine mammal species or stocks, and their habitat. This considers the nature of the potential adverse impact being mitigated (likelihood, scope, range). It further considers the likelihood that the measure will be effective if implemented (probability of accomplishing the mitigating result if implemented as planned), the likelihood of effective implementation (probability implemented as planned); and

(2) The practicability of the measures for applicant implementation, which may consider such things as cost and impact on operations.

For a fuller discussion of the least practicable adverse impact standard, see 89 FR 31488, 31517 (April 24, 2024; NMFS' final rule for Taking and Importing Marine Mammals Incidental to Geophysical Surveys in the Gulf of Mexico.

The mitigation strategies described below are consistent with those required and successfully implemented under previous incidental take authorizations issued in association with in-water construction activities ( e.g., soft-start, establishing shutdown zones). Additional measures have also been incorporated to account for the fact that the planned construction activities would occur offshore. In addition, several measures in this IHA ( i.e., seasonal restrictions, vessel strike avoidance, and clearance and shutdown zones) are more rigorous than measures previously incorporated into the 2023 IHA.

Generally speaking, the mitigation measures considered and required here fall into three categories: temporal (seasonal and daily) work restrictions, real-time measures (shutdown, clearance, and vessel strike avoidance), and noise attenuation/reduction measures. Seasonal work restrictions are designed to avoid or minimize operations when marine mammals are concentrated or engaged in behaviors that make them more susceptible or make impacts more likely, in order to reduce both the number and severity of potential takes, and are effective in reducing both chronic (longer-term) and acute effects. Real-time measures, such as implementation of shutdown and clearance zones, as well as vessel strike avoidance measures, are intended to reduce the probability or severity of harassment by taking steps in real time once a higher-risk scenario is identified ( e.g., once animals are detected within an impact zone). Noise attenuation measures, such as bubble curtains, are intended to reduce the noise at the source, which reduces both acute impacts as well as the contribution to aggregate and cumulative noise that may result in longer-term chronic impacts. Below, we also describe the required training, coordination, and vessel strike avoidance measures that apply to foundation installation and vessel use.

Training and Coordination

NMFS requires all Vineyard Wind's employees and contractors conducting activities on the water, including, but not limited to, all vessel captains and crew, to be trained in marine mammal detection and identification, communication protocols, and all required measures to minimize impacts on marine mammals and support Vineyard Wind 1 compliance with the IHA. Additionally, all relevant personnel and the marine mammal species monitoring team(s) are required to participate in joint, onboard briefings prior to the beginning of project activities. The briefing must be repeated whenever new relevant personnel ( e.g., new PSOs, construction contractors, ( print page 75680) relevant crew) join the project before work commences. During this training, Vineyard Wind 1 is required to instruct all project personnel regarding the authority of the marine mammal monitoring team(s). For example, pile driving personnel are required to immediately comply with any call for a delay or shut down by the Lead PSO. Any disagreement between the Lead PSO and the project personnel must only be discussed after delay or shutdown has occurred. In particular, all captains and vessel crew must be trained in marine mammal detection and vessel strike avoidance measures to ensure marine mammals are not struck by any project or project-related vessel.

Prior to the start of in-water construction activities, Vineyard Wind 1 will conduct training for construction and vessel personnel and the marine mammal monitoring team (PSO and PAM operators) to explain responsibilities, communication procedures, marine mammal detection and identification, mitigation, monitoring, and reporting requirements, safety and operational procedures, and authorities of the marine mammal monitoring team(s). A description of the training program must be provided to NMFS at least 60 days prior to the initial training before in-water activities begin. Vineyard Wind 1 will provide confirmation of all required training documented on a training course log sheet and reported to NMFS Office of Protected Resources prior to initiating project activities.

North Atlantic Right Whale Awareness Monitoring

Vineyard Wind must use available sources of information on North Atlantic right whale presence, including daily monitoring of the Right Whale Sightings Advisory System, U.S. Coast Guard very high-frequency (VHF) Channel 16, WhaleAlert, and the PAM system throughout each day to receive notifications of any sightings, and information associated with any regulatory management actions ( e.g., establishment of zones identifying the need to reduce vessel speeds). Maintaining daily awareness and coordination affords increased protection of North Atlantic right whales by understanding North Atlantic right whale presence in the area through ongoing visual and PAM efforts and opportunities (outside of Vineyard Wind 1 efforts), and allows for planning of construction activities, when practicable, to minimize potential impacts on North Atlantic right whales. The vessel strike avoidance measures apply to all vessels associated with the Project within U.S. waters and on the high seas.

Vessel Strike Avoidance Measures

This final IHA contains numerous vessel strike avoidance measures that reduce the risk that a vessel and marine mammal could collide. While the likelihood of a vessel strike is generally low, it is one of the most common ways that marine mammals are seriously injured or killed by human activities. Therefore, the IHA contains enhanced mitigation and monitoring measures to avoid vessel strikes, to the extent practicable. While many of these measures are proactive, intending to avoid the heavy use of vessels during times when marine mammals of particular concern may be in the area, several are reactive and occur when a project personnel sights a marine mammal. Vineyard Wind 1 is required to comply with these measures except under circumstances when doing so would create an imminent and serious threat to a person or vessel or to the extent that a vessel is unable to maneuver and, because of the inability to maneuver, the vessel cannot comply.

While underway, Vineyard Wind 1 is required to monitor for and maintain a safe distance from marine mammals, and operate vessels in a manner that reduces the potential for vessel strike. Regardless of the vessel's size, all vessel operators, crews, and dedicated visual observers ( i.e., PSO or trained crew member) must maintain a vigilant watch for all marine mammals and slow down, stop their vessel, or alter course as appropriate to avoid striking any marine mammal. The dedicated visual observer, equipped with suitable monitoring technology ( e.g., binoculars, night vision devices), must be located at an appropriate vantage point for ensuring vessels are maintaining required vessel separation distances from marine mammals ( e.g., 500 m from North Atlantic right whales).

For all project-related vessels, regardless of size, the vessel operator is required to immediately reduce speeds to 10 kn (11.5 mph) or less if any large whale, mother/calf pair, or large assemblage of non-delphinid cetaceans are observed within 500 m of the vessel. Additionally, all project vessels, regardless of size, must maintain a 500-m minimum separation zone from North Atlantic right whales, and a 100-m minimum separation zone from sperm whales and non-North Atlantic right whale baleen species. Vessels are also required to keep a minimum separation distance of 50 m from all delphinid cetaceans and pinnipeds, with an exception made for those species that approach the vessel ( i.e., bow-riding dolphins) (table 10). All reasonable steps must be taken to not violate minimum separation distances. If any of these species are sighted within their respective minimum separation zone, the underway vessel must shift its engine to neutral (if it is safe to do so) and turn away from the animal(s). The engines must not be engaged until the animal(s) have been observed to be outside of the vessel's path and beyond 100 m (for sperm whales and non-North Atlantic right whale large whales) or 50 m (for delphinids and pinnipeds).

If any North Atlantic right whales are sighted at any distance by any project personnel or acoustically detected, project vessels must reduce speeds to 10 kn (11.5 mph) and turn away from the animal. Additionally, if any large whale (other than a North Atlantic right whale) is sighted within 500 m of an underway vessel by project personnel, the vessel is required to immediately reduce speeds to 10 kn (11.5 mph) or less and turn away from the animal.

All of the Project-related vessels are required to comply with the measures within this IHA for operating vessels around North Atlantic right whales and other marine mammals, as well as any existing NMFS vessel speed restrictions in effect for North Atlantic right whales (see 50 CFR 224.105). When NMFS vessel speed restrictions are not in effect and a vessel is traveling at greater than 10 kn (11.5 mph), in addition to the required dedicated visual observer, Vineyard Wind 1 is required to monitor the transit corridor, defined as from a port to the lease area or return, in real-time with PAM prior to and during transits. To maintain awareness of North Atlantic right whale presence in the Project Area, vessel operators, crew members, and the marine mammal monitoring team will monitor U.S. Coast Guard VHF Channel 16, WhaleAlert, the Right Whale Sighting Advisory System (RWSAS), and the PAM system. Any North Atlantic right whale or large whale detection will be immediately communicated to PSOs, PAM operators, and all vessel captains. All vessels will be equipped with a properly installed, operational AIS and Vineyard Wind 1 must report all MMSI numbers to NMFS Office of Protected Resources prior to initiating in-water activities. Vineyard Wind 1 must submit a Marine Mammal Vessel Strike Avoidance Plan that must be approved by NMFS prior to commencement of vessel use, and Vineyard Wind 1 must abide by this plan.

Compliance with these measures will reduce the likelihood of vessel strike to the extent practicable. These measures ( print page 75681) increase awareness of marine mammals in the vicinity of project vessels and require project vessels to reduce speed when marine mammals are detected (by PSOs, PAM, and/or through another source, e.g., RWSAS) and maintain separation distances when marine mammals are encountered. While visual monitoring is useful, reducing vessel speed is one of the most effective, feasible options available to reduce the likelihood of and effects from a vessel strike. Numerous studies have indicated that slowing the speed of vessels reduces the risk of lethal vessel collisions, particularly in areas where right whales are abundant and vessel traffic is common and otherwise traveling at high speeds (Vanderlaan and Taggart, 2007; Conn and Silber, 2013; Van der Hoop et al., 2014; Martin et al., 2015; Crum et al., 2019).

Given the inherent low probability of vessel strike, combined with the vessel strike avoidance measures included herein, NMFS considers the potential for vessel strike to be unlikely and does not authorize take from this activity under this IHA.

Table 10—Vessel Strike Avoidance Separation Zones

Marine mammal species	Vessel separation zone (m)
North Atlantic right whale	500
Other ESA-listed species and non-North Atlantic right whale large whales	100
Other marine mammals a	50
a  With the exception of seals and delphinid(s) from the genera Delphinus, Lagenorhynchus, Stenella, or Tursiops, as described below.

Seasonal and Daily Restrictions

Temporal restrictions in places where marine mammals are concentrated, engaged in biologically important behaviors, and/or present in sensitive life stages are effective measures for reducing the magnitude and severity of human impacts. The temporal restrictions described here are built around North Atlantic right whale protection. Based upon the best scientific information available (Roberts et al., 2023), the highest densities of North Atlantic right whales in the specific geographic region are expected during the months of January through May, with an increase in density starting in December. However, North Atlantic right whales may be present in the LIA throughout the year.

NMFS is requiring seasonal work restrictions to minimize risk of noise exposure to the North Atlantic right whales incidental to pile driving activities to the extent practicable. These seasonal work restrictions are expected to reduce the number of takes of North Atlantic right whales and further reduce vessel strike risk. These seasonal restrictions also afford protection to other marine mammals that are known to use the LIA with greater frequency during winter months, including other baleen whales.

As described previously, no impact pile driving activities may occur January 1 through May 31st. Vineyard Wind plans to install no more than 1 pile per day and only initiate impact pile driving during daylight hours. Foundation installation will not be initiated later than 1.5 hours before civil sunset. Generally, foundation installation may continue after dark when the installation of the same pile began during daylight (1.5 hours before civil sunset), when clearance zones were fully visible for at least 30 minutes and must proceed for human safety or installation feasibility reasons.

Monopiles must be no larger than 9.6 m in diameter. The impact hammer operator must not exert more than 4,000 kJ on the pile being installed. No more than one pile may be installed at a given time ( i.e., concurrent/simultaneous pile driving may not occur).

Noise Attenuation Systems

Vineyard Wind 1 is required to employ noise abatement systems (NASs), also known as noise attenuation systems, during all foundation installation activities to reduce the sound pressure levels that are transmitted through the water. This will reduce acoustic ranges to the Level A harassment and Level B harassment acoustic thresholds and minimize, to the extent practicable, any acoustic impacts resulting from these activities. Vineyard Wind is required to use a double big bubble curtain (DBBC) and HSD in addition to an enhanced BBC maintenance schedule. The refined NAS design (DBBC + HSD + enhanced BBC maintenance schedule) used during the 2023 construction activities will be used on the 15 remaining piles to minimize noise levels. A single bubble curtain, alone or in combination with another NAS device, may not be used for pile driving, as received SFV data reveals this approach was unlikely to attenuate sound sufficiently to be consistent with the target sound reduction of 6 dB. Moreover, the Level B harassment take estimates and impact analysis, as well as the associated findings, are based upon the assumption that the refined NAS design (DBBC + HSD + enhanced BC maintenance schedule) will be used and that the ensonification distances measured in the 2023 SFVs under the same conditions will occur for the 15 remaining piles. The DBC and HSD must reduce noise levels to those not exceeding expected ranges to Level A harassment and Level B harassment isopleths corresponding to those modeled assuming 6-dB sound attenuation, pending results of SFV (see Sound Field Verification section below).

Noise abatement systems, such as bubble curtains, are used to decrease the sound levels radiated from a source. Bubbles create a local impedance change that acts as a barrier to sound transmission. The size of the bubbles determines their effective frequency band, with larger bubbles needed for lower frequencies. There are a variety of bubble curtain systems, confined or unconfined bubbles, and some with encapsulated bubbles or panels. Attenuation levels also vary by type of system, frequency band, and location. Small bubble curtains have been measured to reduce sound levels, but effective attenuation is highly dependent on depth of water, current, and configuration and operation of the curtain (Austin et al., 2016; Koschinski and Lüdemann, 2013). Bubble curtains vary in terms of the sizes of the bubbles; those with larger bubbles tend to perform a bit better and more reliably, particularly when deployed with two separate rings (Bellmann, 2014; Koschinski and Lüdemann, 2013; Nehls et al., 2016). Encapsulated bubble systems ( i.e., HSDs) can be effective within their targeted frequency ranges ( e.g., 100-800 Hz) and when used in conjunction with a bubble curtain appear to create the greatest attenuation. The literature presents a wide array of observed attenuation results for bubble curtains. The variability in attenuation levels is the result of variation in design as well as differences in site conditions ( print page 75682) and difficulty in properly installing and operating in-water attenuation devices. Dähne et al. (2017) found that single bubble curtains that reduce sound levels by 7 to 10 dB reduced the overall sound level by approximately 12 dB when combined as a double bubble curtain for 6-m steel monopiles in the North Sea. During installation of monopiles (consisting of approximately 8-m in diameter) for more than 150 WTGs in comparable water depths (>25 m) and conditions in Europe indicate that attenuation of 10 dB is readily achieved (Bellmann, 2019; Bellmann et al., 2020) using single BBCs for noise attenuation.

When a double big bubble curtain is used, Vineyard Wind 1 will be required to maintain numerous operational performance standards, including the enhanced BBC maintenance protocol (Vineyard Wind 1 Enhanced BBC Technical Memo, 2023). These standards are defined in the IHA and include, but are not limited to, a requirement that construction contractors train personnel in the proposed balancing of airflow to the bubble ring; and a requirement that Vineyard Wind 1 submit a performance test and maintenance report to NMFS within 72 hours following the performance test. Corrections to the attenuation device to meet regulatory requirements must occur prior to use during foundation installation activities. In addition, a full maintenance check ( e.g., manually clearing holes) must occur prior to each pile being installed. The HSD system Vineyard Wind 1 plans to use would be employed, in coordination with the DBBC, as a near-field attenuation device close to the monopiles (Küsel et al., 2024). Vineyard Wind 1 also plans to follow a DBBC enhanced maintenance protocol, which was used during the 2023 Vineyard Wind 1 pile installation activities. The DBBC enhanced maintenance protocol includes an adjustment from typical bubble curtain operations to drill hoses after every deployment to maximize performance in siltier sediments which are present in the Lease Area. The DBBC enhanced maintenance protocol also includes DBBC hose inspection and clearance, pressure testing of DBBC hoses, visual inspection of DBBC performance, and minimizing disturbance of the DBBC hoses on the seafloor.

Vineyard Wind 1 is required to submit an updated SFV plan to NMFS for approval prior to installing foundations, and must abide by this plan. Vineyard Wind 1 is also required to submit interim and final SFV data results to NMFS and make corrections to the NASs in the case that any SFV measurements demonstrate noise levels are above those expected. These frequent and immediate reports allow NMFS to better understand the sound fields to which marine mammals are being exposed and require immediate corrective action should they be misaligned with anticipated noise levels within our analysis.

Clearance and Shutdown Zones

NMFS requires the establishment of both clearance and shutdown zones during impact pile driving. The purpose of “clearance” of a particular zone is to minimize potential instances of auditory injury and more severe behavioral disturbances by delaying the commencement of an activity if marine mammals are near the activity. The purpose of a “shutdown” is to prevent a specific acute impact, such as auditory injury or severe behavioral disturbance of sensitive species, by halting the activity. Due to the increased density of North Atlantic right whales during the months of November and December, as compared to densities in June through October, more stringent clearance and shutdown mitigation measures are planned for these months.

All relevant clearance and shutdown zones during project activities will be monitored by NMFS-approved PSOs and PAM operators. PAM would be conducted at least 24 hours in advance of any pile driving activities. At least one PAM operator would review data from at least 24 hours prior to foundation installation (to increase situational awareness) and actively monitor hydrophones for 60 minutes prior to commencement of these activities. Any North Atlantic right whale sighting at any distance by visual PSOs, or acoustically detected within the PAM monitoring zone (10 km), triggers a delay to commencing pile driving or a shutdown. Any large whale sighted by a PSO or acoustically detected by a PAM operator that cannot be identified as a non-North Atlantic right whale must be treated as if it were a North Atlantic right whale.

Prior to the start of pile driving activities, Vineyard Wind must ensure designated areas ( i.e., clearance zones, table 11) are clear of marine mammals before commencing activities to minimize the potential for and degree of harassment. PSOs must visually monitor clearance zones for marine mammals for a minimum of 60 minutes prior to commencing foundation installation activities. During this period, the clearance zones will be monitored acoustically by a PAM operator as well. All clearance zones (table 11) must be confirmed to be free of marine mammals for 30 minutes immediately prior to commencing foundation installation activities. The minimum visibility zone, defined as the area over which PSOs must be able to visually detect marine mammals, would extend 4,000 m for monopile installation from the pile being driven (table 11) and must be visible for 60 minutes. The minimum visibility zone corresponds to the modeled Level A harassment distance for low-frequency cetaceans plus twenty percent, and rounded up to the nearest 0.5 km. The minimum visibility zone must be visually cleared of marine mammals. If this zone is obscured to the degree that effective monitoring cannot occur, pile driving must be delayed. Minimum visibility zone and clearance zones are defined and provided in table 11 for all species.

From November 1 to December 31, vessel-based surveys will be used to confirm the clearance zone (10 km PAM clearance zone (6.2 mi); table 11) is clear of North Atlantic right whales prior to pile driving. The survey will be supported by a team of nine PSOs coordinating visual monitoring across two PSO support vessels and the pile driving platform. The two PSO support vessels, each with three active on-duty PSOs, will be positioned at the same distance on either side of the pile driving vessel. Each PSO support vessel would transit along a steady course along parallel track lines in opposite directions. Each transect line will be surveyed at a similar speed, not to exceed 10 kn (11.5 mph) and would last for approximately 30 minutes to 1 hour. If a North Atlantic right whale is sighted at any distance during the vessel-based survey, pile driving must be delayed until the following day unless an additional vessel-based survey with additional transects is conducted to determine the clearance zone is clear of North Atlantic right whales. Further details on PSO support vessel monitoring efforts are described in the Vineyard Wind 1 application section 11, table 17.

Once pile driving activity begins, any marine mammal entering their respective shutdown zone will trigger the activity to cease. In the case of pile driving, the shutdown requirement may be waived if is not practicable due to imminent risk of injury or loss of life to an individual or risk of damage to a vessel that creates risk of injury or loss of life for individuals, or if the lead engineer determines there is pile refusal or pile instability.

In situations when shutdown is called for, but Vineyard Wind 1 determines shutdown is not practicable due to aforementioned emergency reasons, ( print page 75683) reduced hammer energy must be implemented when the lead engineer determines it is practicable. Specifically, pile refusal or pile instability could result in the inability to shut down pile driving immediately. Pile refusal occurs when the pile driving sensors indicate the pile is approaching refusal, and a shut-down would lead to a stuck pile which then poses an imminent risk of injury or loss of life to an individual, or risk of damage to a vessel that creates risk for individuals. Pile instability occurs when the pile is unstable and unable to stay standing if the piling vessel were to “let go.” During these periods of instability, the lead engineer may determine a shut-down is not feasible because the shut-down combined with impending weather conditions may require the piling vessel to “let go” which then poses an imminent risk of injury or loss of life to an individual, or risk of damage to a vessel that creates risk for individuals. Vineyard Wind 1 must document and report to NMFS all cases where the emergency exemption is taken.

After shutdown, impact pile driving may be reinitiated once all clearance zones are clear of marine mammals for the minimum species-specific periods, or, if required to maintain pile stability, impact pile driving may be reinitiated but must be used to maintain stability. From June 1-October 31, if pile driving has been shut down due to the presence of a North Atlantic right whale, pile driving must not restart until the North Atlantic right whale has not been visually or acoustically detected for 30 minutes. Upon re-starting pile driving, soft-start protocols must be followed if pile driving has ceased for 30 minutes or longer. From November 1-December 31, if a North Atlantic right whale is detected either via real-time PAM or vessel-based surveys at any distance from the pile driving location, pile driving must be delayed and must not commence until the following day unless a follow-up vessel-based survey confirms the clearance zone is clear of North Atlantic right whales upon completion of the survey, as determined by the lead PSO. During November 1-December 31, if pile driving has been shut down or delayed due to the presence of 3 or more North Atlantic right whales, pile driving will be postponed until the next day. Shutdown zones vary by species and are shown in table 11 below.

Table 11—Minimum Visibility, Clearance, Shutdown, and Level B Harassment Zones, in Meters ( m ), During Impact Pile Driving

Monitoring zones	North Atlantic right whales a	Other mysticetes/sperm whales (m) b	Pilot Whales, harbor porpoises, and delphinids (m) b	Pinnipeds (m) b
Minimum Visibility Zone c	4,000
Visual Clearance Zone	Any distance from pile driving PSOs	500	160	160
PAM Clearance and Shutdown Zone d	10,000	500	160	160
Visual Shutdown Zone	Any distance from pile driving PSOs	500	160	160
Distance to Level B Harassment Threshold	5,720
a  From December 1-December 31, vessel based surveys using two PSO support vessels would confirm the 10 km (6.2 mi) PAM clearance zone is clear of North Atlantic right whales. If three or more North Atlantic right whales are sighted in November or December, pile driving will be delayed for 24 hours.
b  Pile driving may commence when either the marine mammal has voluntarily left the respective clearance zone and has been visually confirmed beyond that clearance zone, or when 30 minutes (North Atlantic right whales (June-October), other non-North Atlantic right whale mysticetes, sperm whales, pilot whales, Risso's dolphins) or 15 minutes (all other delphinids and pinnipeds) have elapsed without re-detection .
c  Minimum visibility zone is the minimum distance that must be visible prior to initiating pile driving, as determined by the lead PSO. The minimum visibility zone corresponds to the Level A harassment distance for low-frequency cetaceans plus twenty percent, and rounded up to the nearest 0.5 km.
d  The PAM system must be capable of detecting North Atlantic right whales at 10 km during pile driving. The system should also be designed to detect other marine mammals to the maximum extent practicable; however, it is not required these other species be detected out to 10 km given higher frequency calls and echolocation clicks are not typically detectable at large distances.