Abstract
This is the Protected Species Report for the Mayflower Wind high resolution geophysical (HRG) site characterization survey completed under: the Mayflower Wind 2021 Incidental Harassment Authorization (IHA); the 2021 Mayflower Wind Geophysical and Geotechnical Survey Plan, including addendums and modifications approved by the Bureau for Ocean Energy Management (BOEM), and stipulations in the Commercial Lease for Renewable Energy Development in Outer Continental Shelf (OCS) lease area OCS-A 0521 (Lease), as modified by waivers approved by BOEM.
The Mayflower Wind HRG survey was conducted by Fugro within state and federal waters in the Mayflower Wind Offshore Project Area including two export cable corridors (ECC) from the lease area to Falmouth, MA and to Brayton Point in Somerset, MA. The report covers the protected species mitigation and monitoring efforts undertaken by Protected Species Observers (PSOs) that were provided by RPS and deployed to each HRG survey vessel.
Fugro conducted HRG operations using four survey vessels: GO Liberty from 02 May to 10 September 2021; GO Pursuit from 17 April to 08 September 2021 and 01 December to 15 December 2021; Westerly from 14 April to 14 October 2021; and Fugro Brasilis from 29 November to 08 December 2021.
In 2021, Mayflower conducted HRG surveys under the 2020 IHA from 14 April 2021 through 06 July 2021. NMFS signed Mayflower’s 2021 IHA on 01 July 2021 (Appendix A), and surveys continued under the 2021 IHA until 15 December 2021. The 2021 HRG Survey Environmental Monitoring Plan (EMP) is included as Appendix B.
Four PSOs were deployed to the GO Pursuit and Fugro Brasilis to undertake 24-hour visual monitoring and implement mitigation during survey operations. Two PSOs were deployed to the GO Liberty to undertake visual observations and implement mitigation to support their daytime-only survey operations. One PSO was deployed to the Westerly to conduct visual observation and implement mitigation to support daytime-only survey operations. Mitigation protocols for the survey included: establishment of exclusion zones (EZ) for marine mammals and other protected species including sea turtles; visual monitoring; and strike avoidance mitigation measures.
Visual observations were conducted by PSOs for a total of 3223 hours and 43 minutes.
A total of 187 visual detection events of marine mammals were made during the survey, consisting of three whale species, two delphinid species, and one seal species. Whale species observed included fin whales (Balaenoptera physalus), humpback whales (Megaptera novaeangliae), and minke whales (Balaenoptera acutorostrata). Delphinids observed included common dolphins (Delphinus delphis) and bottlenose dolphins (Tursiops truncatus). Seal sightings consisted of gray seals (Halichoerus grypus). There were also additional unidentified whales, unidentified delphinids and unidentified seals.
There were 11 sightings of sea turtles that included a leatherback sea turtle (Dermochelys coriacea), Kemp’s Ridley sea turtle (Lepidochelys kempii) and loggerhead sea turtle (Caretta caretta).
There was one sighting of a marine mammal carcass. The carcass was observed to be highly decomposed and there were no indications that the Mayflower Wind survey activities had caused or contributed to the death of the animal.
In accordance with stipulations set forth in BOEM Lease and the NMFS 2021 IHA conditions, a total of 31 mitigation actions were implemented for the HRG sound sources including shutdowns of the sound sources (23 times) and delays to activation of the acoustic sources (8 times). On three occasions strike avoidance maneuvers were executed during protected species detections, two times for gray seals and once for humpback whales.
The 2021 IHA authorized 3445 Level B takes for 13 species of marine mammals, including six whale species, five delphinids, two pinniped species and one species of porpoise. The IHA also included authorization for unidentified whales and dolphins. No Level A takes were authorized for any species.
A total of 395 individual marine mammals from three species were observed within the predicted 160 decibel radius (where there is a potential for a behavioral response) while an HRG source was active, constituting potential Level B takes. Potential Level B takes included one humpback whale, 33 bottlenose dolphins, and 359 common dolphins. An additional two unidentified whales that could not be identified to species level were observed inside the predicted Level B take zone.