Abstract
Development of offshore wind capacity along the East Coast of the United States continues to progress with plans for more than one thousand turbines planned coastwide over the next decade (BOEM 2022). In many instances, the construction and operation of turbines spatially overlap with other ocean uses, such as commercial fishing. While the impact on fishing is likely variable across regions and species, it is imperative to characterize these impacts across the spatiotemporal scale associated with the life cycle of the development.
Located 27 miles off the coast of Virginia Beach, Virginia, the Coastal Virginia Offshore Wind (CVOW) 3,000-megawatt project will be built in water depths ranging from 18 to 42 meters (m), and the seafloor is primarily sandy benthic habitat. These bottom habitats are potentially suitable for Atlantic surfclams (Spisula solidissima solidissima) and have historically supported a commercial fishery in the area. Until recently, fishery efforts off the coast of Virginia along the southern edge of the surfclam range were low. However, commercial surfclam fishing efforts off Virginia resumed in 2021 with the fishery harvesting surfclams to the east of the CVOW site.
Given the spatial overlap between the Atlantic surfclam resource and the offshore wind lease, Dominion Energy worked with project Principal Investigators (PIs) to develop and execute a survey, in alignment with ROSA Offshore Wind Project Monitoring Framework and Guidelines (ROSA 2021), to characterize Atlantic surfclam abundance, and document spatial distribution and population structure.
This surfclam survey observed relatively high total biomass and density of surfclams within and around the CVOW lease area; total biomass observed here was more than double that observed in lease areas off New Jersey in the central portion of the fishing stock. However, the surfclams collected in and around the CVOW lease were almost exclusively smaller than 120mm throughout the surveyed area, meaning that the exploitable biomass (the biomass of surfclams >120mm) was relatively low. A spatial pattern in abundance was evident with highest biomass in the south, and biomass gradually decreasing northward. For example, surfclam biomass in the southern control was over 50 times higher than that observed in the northern control.
Surfclams observed during this survey represented age classes from < 1 year old (collected in benthic grabs) through 9 years old. Age classes 1 through 6 are consistently observed suggesting that recruitment of surfclams has been consistent over the past 5 to 6 years. Additionally, the genetic patterns observed in this survey indicated that a mix of S.s.solidissima and S.s.similis was widely distributed throughout the CVOW lease and adjacent areas.