Management Strategy Evaluation for the Atlantic Surfclam Spisula solidissima Using a Fisheries Economics Model

The Atlantic surfclam, Spisula solidissima, is an economically valuable bivalve fished along the northeastern US. Fishable biomass has declined and the surfclam’s range has contracted as the center of the stock’s distribution has shifted north, primarily driven by warmer bottom water temperatures. Declining landings per unit effort in the Mid-Atlantic Bight (MAB) is one result. Stock characteristics suggest that local overfishing may be occurring off New Jersey. The objective of this project is to carry out a management strategy evaluation (MSE) with terminal goals being enhanced surfclam productivity in the MAB and increased fishery viability. The model uses individual boats fishing a spatially structured stock under economic and quota constraints and subject to captain’s behaviors. Management alternatives include two closure rules and three closure durations. Simulations showed that LPUE increased under most alternate strategies, by up to 21%, compared to present-day management. The number of clams per bushel was up to 7% greater suggesting that the alternative strategies resulted in the landing of larger clams. Stock biomass increased under most alternate strategies, up to 17%, compared to present-day management. These outcomes suggest that the MSE approach could be valuable in insulating the stock and commercial fishery from further decline.