CHANGES IN HARVEST PATTERNS AND ASSESSMENT OF POSSIBLE LONG-TERM IMPACTS ON YIELD IN THE DELAWARE COMMERCIAL BLUE-CRAB FISHERY

During the past 10 years, landings of blue crabs (Callinectes sapidus Rathbun) in Delaware have remained at record high levels, averaging 4. 5 million pounds. The number of fishers participating in the blue crab fishery has increased dramatically during this time despite efforts b y the state to impose a moratorium on new entrants. In addition, effor t. as measured by the number of crab pots fished and amount of boat da ys directed toward crab fishing, has also increased. Catch per unit ef fort (CPUE) began declining in 1990 and has showed signs of stabilizin g since 1992. Concerns that changes in fishing efficiency may be maski ng additional declines in CPUE promoted the development of a relative exploitation analysis based on the three (fall crab pot, peeler, crab dredge) fisheries that harvest components of the spawning stock. Relat ive exploitation rates were found to be increasing over time for all t hree fisheries. Furthermore, an index of spawning stock biomass showed a declining vend since 1985.