Snow crab (Chionoecetes opilio) distribution limits and abundance trends on the Scotian Shelf

Abstract

The distribution and abundance C. opilio near its southern limit of the Scotian Shelf is characterized from commercial fishing locations and from groundfish trawl surveys. Snow crab are most abundant on the eastern Scotian Shelf where bottom temperature is generally <3°C even in summer; they are absent from the deep central Shelf, 'Scotian Gulf', which has access to warmer offshore waters. West of the Scotian Gulf snow crab abundance is low and limited to pockets of cold bottom water. The fishery exploits most of the areas where snow crab are expected to be abundant on the Scotian Shelf. Mean annual catch rate by trawls was correlated with mean annual commercial catch rate for the 1980-94 period. Lower temperatures after 1984 appear to have contributed to expanded habitat, and reduced predation from groundfish may have increased the survival and growth of juvenile and adolescent snow crab on the eastern Scotian Shelf.