Estimation of Sea Scallop Abundance in Closed Areas of Georges Bank, USA

Abstract

A high-resolution video survey conducted from May to September 1999 in historic scallop fishing grounds that have been closed to mobile fishing gear since 1994 revealed some of the highest densities and largest sea scallops Placopecten magellanicus ever observed on Georges Bank. Sea scallop densities ranged from 0.25 to 0.59 scallops/m² within the three surveyed areas and from 0.58 to 1.06 scallops/m² at stations where at least 1 scallop was observed. Sea scallops were highly aggregated into patches (beds) on the scale of square kilometers, and the distribution was strongly associated with the distribution of coarse sand-granule-pebble substrate. The three areas surveyed (1,938 km²) contained approximately 650 million scallops representing 17 million kg of harvestable scallop meats. This is equivalent to 54% of the average harvestable scallop meat biomass from 1977 to 1988. The area surveyed covered 5% of the total scallop fishing grounds of Georges Bank. The video survey technique has several advantages over dredge surveys: it is fast, accurate, and precise and provides information on the biology of scallops and the associated habitat without disturbing the sea floor.