Project Title: Estimating Incidental Mortality in the Sea Scallop Fishery
Client: NOAA/NMFS Sea Scallop Research Set-Aside
The goal of this project was to more accurately estimate scallop incidental mortality using a variety of underwater survey vehicles. All surveys were conducted in southern New England waters in areas with mainly sandy substrate using a standardized Coonamessett Farm Turtle Deflector Dredge (CFTDD) for all tows. Study locations were surveyed before and after dredge tows using the REMUS 100, an autonomous underwater vehicle (AUV) operated by the Woods Hole Oceanographic Institution, the CFF Benthos MiniRover remotely operated vehicle (ROV), and dredge-mounted cameras. CFF also designed a bottom-contacting benthic sled for the project to survey the tow paths. Scallop catch data was recorded for all tows, including the total number of scallops and shell height (SH) and damage condition of each scallop.
Using the scallop abundance estimate from the same REMUS survey, we estimated that the incidental mortality due to scallop dredging during our survey was approximately 1.0%. This estimate is an order of magnitude less than values currently used for sea scallop stock assessment (incidental mortality = 20% on Georges Bank and 10% in the Mid-Atlantic), but it is comparable to the incidental mortality estimates reported in the studies used to derive these values.