Did Ten Billion Juvenile Sea Scallops Die in the Mid-Atlantic Due to Incidental Fishing Mortality?

A single large year class in the Mid-Atlantic consisting of an estimated 1.31 x 10¹⁰ sea scallops was observed in 2003. This year class was 1.1 to 1.6 times greater than the entire scallop stock in any year between 2004 and 2009. Over half of these scallops vanished between 2003 and 2004. This apparent mortality episode was not likely caused by a shift in environmental conditions or by biological factors such as predation, senescence or food limitation. However, the majority of fishing effort during that year was focused in the Mid-Atlantic. During fishing operations these scallops were brought to the surface through water temperatures above the lethal limit and exposed to high air temperatures before being returned to the sea floor several hours later. Therefore, this mass mortality was likely the result of incidental fishing mortality. The recruitment event was reported to managers on 2 July 2003; however the area remained open to fishing for thirteen months before the Elephant Trunk Closed Area was established. Although the Elephant Trunk Closed Area has provided substantial landings for the past 5 years, the potential of the 2003 recruitment event was only partially realized. To achieve the full benefit of extreme recruitment events requires close ecological monitoring of the target species, real-time abundance and size distribution data and a management system that can respond rapidly.