Absolute measures enabling ecosystem-based management for fisheries: The sea scallop example

Sea scallops, Placopecten magellanicus, support one of the most valuable fishing industries in the United States. Large fluctuations in landings during the 1980s and a steady decline in harvest during the mid-1990s had severe effects on the fishing industry. Three large areas, closed in 1994 to protect groundfish stocks, excluded scallopers from historically important fishing grounds on Georges Bank. After four years of closure, scallop biomasses were believed to be high within these areas, but the quantities were unknown. In 1999, we developed a new cooperative video survey protocol designed to estimate the absolute number of scallops in closed and open areas. Since then the sea scallop resource has made a spectacular recovery attaining record landings. In 2003, the survey was expanded to the entire commercial sea scallop resource in US waters. Stock assessment results indicated that sea scallops were no longer overfished. In 2007, it was estimated there were 300 million lbs (130,000 mt) of harvestable scallops on the sea floor worth approximately $2 billion USD. Management of this recovered resource, including the efficiency of area-rotational fishing, effects on marine habitat, and methods for tracking population status of the sea scallops are all under examination.