Vineyard Wind 2020 Survey Season Annual Report: American Lobster, Black Sea Bass, Larval Lobster Abundance Survey, and Lobster Tagging Study of the 501N Study Area

The University of Massachusetts Dartmouth School for Marine Science and Technology (SMAST) and Massachusetts Lobstermen’s Association conducted a standardized ventless lobster trap survey and tagging study in Vineyard Wind’s Lease Area OCS-A 0501 (Lease Area), on the Outer Continental Shelf (OCS). In the northern portion of the Lease Area, termed the 501N Study Area, populations of adult American lobster (Homarus americanus), larval lobster, and black sea bass (Centropritis striata) were sampled and compared to those in the easterly adjacent Control Area.

The primary goal of this project was to identify baseline conditions in the 501N Study Area and adjacent Control Area, to then compare potential impacts on several marine species of proposed wind development activities in the 501N Study Area and the Control Area between years. To establish a baseline, a Before-After-Control-Impact (BACI) design was employed to detect eventual patterns of sustained difference. Our primary objectives for this project were to:

1. estimate the size and distribution of lobster and black sea bass populations in the 501N Study Area and adjacent Control Area;
2. classify population dynamics of these two species such as length, sex, reproductivity success, age, diet, and disease;
3. estimate the relative abundance and distribution of planktonic species such as larval lobster in the neustonic layer of each area, using a towed ichthyoplankton net at each survey location; and
4. obtain movement patterns of adult lobsters through a tagging study.

A total of 921 lobsters were sampled between both study areas and trap types: 662 in the 501N Study Area, with an average size of 87.24±0.73 millimeter (mm), and 259 in the Control Area, with an average size of 93.65±1.19 mm. The 501N Study Area yielded an overall male: female ratio of 2.4:1, and the Control Area ratio was 4.2:1. A total of 456 black sea bass were sampled from commercial-sized sea bass pots at each location; 149 in the 501N Study Area and 307 in the Control Area. Larval lobster samples were collected at each location with a neuston net; for the season we collected 91 total lobster larvae ranging from stages one to four. The average larval lobster density was 0.29 larvae per 1,000 cubed meters (m^3) in the development area and 0.09 larvae per 1,000 m^3 in the Control Area.