Virginia Institute of Marine Science
Journal of Shellfish Research
Size selectivity curves were estimated for two commercial dredge configurations used in the United States Atlantic sea scallop (Placopecten magellanicus) fishery. Traditionally, the New Bedford Style dredge (New Bedford dredge) has been used by the commercial fleet; however, since 2013, the Coonamessett Farm Turtle Deflector Dredge (turtle dredge) has been required seasonally in the Mid-Atlantic region to minimize the capture of sea turtles. This analysis provides estimates of selectivity and relative efficiency for the turtle dredge and the New Bedford dredge. Selectivity information for the turtle dredge is currently unknown, and selectivity for the New Bedford dredge was originally assessed in 2008. The Share Each Length's Catch Total method was used to model scallop catch-at-length data for each commercial dredge with data collected during the Virginia Institute of Marine Science fishery-independent surveys in 2015 to 2017, conducted onboard commercial fishing vessels. The surveys were conducted in the Mid-Atlantic and Georges Bank regions of the resource in three distinct areas. A paired study design was used, where a nonselective National Marine Fisheries Service sea scallop survey dredge and either the turtle dredge or New Bedford dredge were towed simultaneously at each survey station. To assess for time-varying changes in selectivity, results were compared with the 2008 New Bedford dredge analysis. Results indicated the 50% retention length was 98.2 mm, with a selection range of 28.2 mm and a relative efficiency of 0.83 for the turtle dredge. New Bedford dredge results estimated a 50% retention length of 107.4 mm, selection range of 50.5 mm and relative efficiency of 0.81. Comparing selectivity profiles for the turtle dredge and New Bedford dredge with the 2008 results indicated a shift toward increased retention probability for smaller size classes of scallops.
selectivity; Placopecten magellanicus; sea scallop dredge fishery; New Bedford style dredge; Coonamessett Turtle Deflector Dredge;
Roman, Sally and Rudders, David, Selectivity Of Two Commercial Dredges Fished In The Northwest Atlantic Sea Scallop Fishery (2019). Journal of Shellfish Research, 38(3), 573-580.