Size-Selectivity of the Commercial Sea Scallop (Placopecten magellanicus) Dredge: Evaluation the Performance of the New Bedford Style Dredge Configured with 4-Inch Rings and a 10-Inch Twine Top using the SELECT Model
Master of Science (M.Sc.)
Virginia Institute of Marine Science
A size-selectivity curve was constructed to characterize the performance of the New Bedford style Atlantic sea scallop (Placopecten magellanicus) dredge when it is configured to meet the requirements of Amendment #10 to the Sea Scallop Fishery Management Plan. The curve was generated using the SELECT model on catch-at-length data, obtained by simultaneously towing a New Bedford style dredge and a non-selective National Marine Fisheries Service sea scallop survey dredge from commercial scallop vessels. Data were collected during three cruises in the Northwest Atlantic between 2005 and 2006. One cruise was completed in Georges Bank (Groundfish Closed Area II) and two cruises were completed in the mid-Atlantic (both in the Elephant Trunk Closed Area). The resulting selectivity curve for all cruises combined yielded a 50% retention length of 100.1 mm, a selection range of 23.6 mm and a relative efficiency value of 0.77. A length of 100.1 mm corresponds to an age of 4.6 years in Georges Bank and 5.8 years in the mid-Atlantic and a meat-weight of approximately 16 g. This implies that entry into the fishery is being delayed, potentially increasing yield-per-recruit and the population’s total reproductive output. The resultant selectivity curve can assist fisheries managers with stock assessments, mortality calculations and with the interpretation of catch data from government and industry-based surveys. Additionally, the curve can be used to evaluate the effect of future changes to sea scallop dredge design.
© The Author
Yochum, Noelle, "Size-Selectivity of the Commercial Sea Scallop (Placopecten magellanicus) Dredge: Evaluation the Performance of the New Bedford Style Dredge Configured with 4-Inch Rings and a 10-Inch Twine Top using the SELECT Model" (2006). Dissertations, Theses, and Masters Projects. William & Mary. Paper 1539617841.