MEPS 347:39-49 (2007)  -  DOI: https://doi.org/10.3354/meps07057

ABSTRACT: High sea scallop abundances such as those in the closed areas of Georges Bank may cause predators, including sea stars, to aggregate and cause increased natural mortality rates for sea scallops. We hypothesized that sea stars are aggregated and are of larger size in areas of Georges Bank that are closed to fishing. Between 1999 and 2003, we systematically video surveyed 3809 stations (4 quadrats per station) in areas open and closed to fishing on Georges Bank. Sea stars were aggregated within the closed areas from 2000 to 2003. Sea star densities were higher in the closed areas than in the open areas during each year from 2000 to 2003. The average arm length of sea stars within the open areas was not always smaller or larger than those in the closed areas; however, average arm length estimates were influenced by the abundance of sea star recruits. Sea scallop densities were independent of sea star densities. Sea star predation influenced sea scallop densities in specific locations, as instantaneous natural mortality rates were high.

KEY WORDS: Sea star · Asterias spp. · Sea scallop · Placopecten magellanicus · Closed areas · Georges Bank · Video survey