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Federal Register / Vol. 86, No. 23 / Friday, February 5, 2021 / Notices Monopile Installation Seasonal Restriction on Impact Pile Driving No impact pile driving activities would occur January 1 through April 30.
This seasonal restriction would minimize the potential for North Atlantic right whales to be exposed to pile driving noise. Based on the best available information Kraus et al., 2016; Roberts et al., 2020, the highest densities of North Atlantic right whales in the project area are expected during the months of January through April.
This restriction is expected to greatly reduce the potential for North Atlantic right whale exposure to pile driving noise associated with the proposed project.
Clearance and Exclusion Zones South Fork Wind would use PSOs to establish clearance zones around the pile driving equipment to ensure these zones are clear of marine mammals prior to the start of pile driving. The purpose of clearance of a particular zone is to prevent potential instances of auditory injury and potential instances of more severe behavioral disturbance as a result of exposure to pile driving noise serious injury or death are unlikely outcomes even in the absence of mitigation measures by delaying the activity before it begins if marine mammals are detected within certain pre-defined distances of the pile driving equipment. The primary goal in this case is to prevent auditory injury Level A harassment, and the proposed clearance zones are larger than the modeled distances to the isopleths assuming an effective 10 dB attenuation of pile driving noise corresponding to Level A harassment for all marine
mammal species excluding humpback whales. These zones vary depending on species and are shown in Table 24. All distances to the perimeter of clearance zones are the radius from the center of the pile. The pre-start clearance zones for large whales, harbor porpoises, and seals are based upon the maximum distance to the Level A harassment isopleth for each group excluding humpback whales plus a 20 percent buffer, rounded up for PSO clarity. The North Atlantic right whale Level A
harassment zone is conservatively based on the Level B harassment zone, and the distance to the perimeter of the clearance zone is rounded up from 4,684 m to 5,000 m. Although the Level A harassment zones are small, midfrequency cetacean except sperm whales zones were established using a precautionary distance of 100 m and will extend to that distance or just beyond the placement of the noise mitigation system, whichever is further.
The exclusion zones for large whales, North Atlantic right whale, porpoise, and seals are based upon the maximum Level A harassment zone for each group excluding humpback whales, increased by a 10 percent buffer and rounded up for PSO clarity. Similar to clearance zones, mid-frequency cetacean except sperm whale exclusion zones will extend to the larger of two distances: 50 m or just outside the noise mitigation system.
The Level A harassment zone is larger for humpback whales than other low frequency baleen whales because animal movement modeling used to estimate the associated isopleth relies on behavior-based exposures with no aversion based on the best available data that inform the animat models;
specific movement parameters help
drive the larger zone size for humpbacks, including a modeled preference for slightly deeper water than the depths in the SFWF. This modeled preference resulted in fewer exposures, but each exposure was farther from the impact piling location, producing the larger Level A harassment zone. While the clearance zone 2,200 m for humpback whales is smaller than the Level A harassment zone 3,642 m, visual monitoring would be conducted from both the construction vessel and a secondary, smaller vessel on which dedicated PSOs would be deployed surveying the circumference of the construction vessel at a radius approximate to the pre-start clearance zone for large whales 2,200 m. NMFS
expects that this additional visual monitoring would facilitate detection of humpback whales within the Level A
harassment zone.
South Fork Wind would establish a clearance zone for North Atlantic right whales slightly larger than the Level B
harassment zone to minimize all take. If a North Atlantic right whale is detected nearing the exclusion zone, shutdown would be triggered. NMFS agrees that, under typical conditions, South Fork Wind would be capable of monitoring this zone using a combination of visual monitoring from both the construction vessel and secondary monitoring vessel described above, and real-time PAM, which would occur before, during, and after driving using a combination of acoustic detection systems e.g., moored buoys, free-floating arrays.
Communication of marine mammal detections, either visual or acoustic, among PSOs on both vessels and PAM
operators would facilitate both clearance of the zone and initiation of shutdown, if required.

TABLE 24PROPOSED CLEARANCE AND EXCLUSION ZONES 1 DURING SOUTH FORK WIND IMPACT PILE DRIVING WITH A
NOISE MITIGATION SYSTEM
Level A
harassment zone m SEL

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Species
Low-frequency Cetaceans:
Fin whale
Minke whale
Sei whale
Humpback whale
North Atlantic right whale
Blue whale 2
Mid-frequency Cetaceans:
Sperm whale
Atlantic spotted dolphin
Atlantic white-sided dolphin
Common dolphin
Rissos dolphin
Bottlenose dolphin
Long-finned pilot whale
High-frequency Cetaceans:

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Level A
harassment zone m PK

Level B
harassment zone m
Pre-start clearance zone m
Exclusion zone m
Vessel separation distance m
1,756
1,571
1,769
3,642
1,621
1,756

10
10
10
10
10
10

4,684
4,684
4,684
4,684
4,684
4,684

2,200
2,200
2,200
2,200
5,000
2,200

2,000
2,000
2,000
2,000
2,000
2,000

100
100
100
100
500
100

10
10
10
10
10
10
10

4,684
4,684
4,684
4,684
4,684
4,684
4,684

2,200
100
100
100
100
100
100

2,000
50
50
50
50
50
50

100
50
50
50
50
50
50

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