Changes in the composition of snow crab (Chionoecetes opilio) participating in the annual breeding migration in Bonne Bay, Newfoundland
Ennis, GP.; Hooper, RG.; Taylor, DM.
Canadian Journal of Fisheries and Aquatic Sciences 4711: 2242-2249
ISSN/ISBN: 0706-652X DOI: 10.1139/f90-249
Sexually-paired snow crabs (Chionoecetes opilio) participating in an annual spring breeding migration to shallow water in Bonne Bay, Newfoundland were collected by SCUBA divers from 1984 to 1989. In 1984 the breeding pairs were composed mainly of relatively large, old-shell animals of both sexes, but by 1988 much smalller animals, most of which were new-shell, dominated the migration. Evidence from research fishing indicates that these changes are related to a rapid decline in what was characteristically a virgin population in 1984 and a coinciding strong pulse of recruitment into the breeding component of the population. A very high incidence of small, subcommercial males participating in the 1988 and 1989 breeding migrations demonstrates a capacity for maintaining a high level of reproductive potential in a snow crab population despite high exploitation rates on larger animals in the male-only fishery for this species. The strong recruitment pulse which occurred in Bonne Bay as the virgin population declined after 1984 also indicates a capacity for enhanced annual production within a snow crab population when exploitation rates are high.