Stock Definition and Recruitment: Implications for the U.S. Sea Scallop (Placopecten magellanicus) Fishery from 2003 to 2011

The United States sea scallop management plan applies fishing mortality in a uniform manner, assigning a single value of instantaneous fishing mortality (F) to the entire resource. Applying a single value of fishing mortality assumes the scallop resource is a single population. Dividing the resource into Georges Bank and Mid-Atlantic Bight reveals that each has been either excessively fished or underutilized based on the present definition of optimum yield. The sea scallop resource was highest in 2003 and has declined by about 50,000 metric tons, entirely from the Mid-Atlantic Bight. Abundance and the corresponding harvest levels will likely continue if the resource is a single population and scallops in the closed areas of Georges Bank populate the entire resource. Abundance and the corresponding harvest levels will likely decline if Georges Bank and the Mid-Atlantic Bight are separate populations in that scallops within these areas have a closed lifecycle. The depletion of the large number of small scallops in the Mid-Atlantic observed in 2003, and poor recruitment from 2009 to 2011, could lead to a rapid reduction in abundance, seriously impacting the fishery that was valued at US$455 million in 2010.