Date of Award

Fall 12-11-2015

Degree Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Coastal Sciences, Gulf Coast Research Laboratory

Committee Chair

Eric N. Powell

Committee Chair Department

Coastal Sciences, Gulf Coast Research Laboratory

Committee Member 2

John M. Klinck

Committee Member 3

Robert T. Leaf

Committee Member 3 Department

Coastal Sciences, Gulf Coast Research Laboratory

Abstract

The Atlantic surfclam, Spisula solidissima, is an economically valuable bivalve harvested along the northeastern United States. The surfclam’s range has contracted and the center of the stock’s distribution has shifted north driven by warmer bottom water temperatures. Declining landings per unit effort (LPUE) in the Mid-Atlantic Bight (MAB) is one result. Declining stock abundance and LPUE suggest that overfishing may be occurring off New Jersey. The objective of this project is to perform a management strategy evaluation (MSE) for Spisula solidissima. The terminal goal is to identify a preferred management option that promotes enhanced surfclam productivity in the MAB and increased fishery viability as indicated by improvement in performance metrics. The active agents of the MSE model are individual fishing boats with economic and quota constraints influenced by captain’s behaviors over a spatially varying population. Management alternatives include two closure rules and three closure durations. Simulations showed that LPUE increased under most alternative strategies, by up to 21%, compared to present-day management. The number of clams per bushel was up to 7% greater under present-day management suggesting that the alternative strategies resulted in the landing of larger clams. Stock biomass increased under most alternate strategies, up to 17%, compared to stock biomass using present-day management. When incidental mortality increased, the benefits seen under alternative management were enhanced. Benefits of alternative management under reduced abundances remained equivalent or increased in comparison to results with present-day abundance. These outcomes suggest that the preferred management option identified by the MSE approach could be valuable in insulating the stock and commercial fishery from further decline.

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