A SNOW CRAB, CHIONOECETES-OPILIO (DECAPODA, MAJIDAE), FISHERY COLLAPSE IN NEWFOUNDLAND

A fishery for snow crab, Chionoecetes opilio, began in 1979 in a shall ow water (<200 m) area off the Avalon Peninsula of southeastern Newfou ndland and developed rapidly with landings peaking at 8609 metric tons (t) in 1981. Landings began to decline in 1982, and dropped to 74 t i n 1985. This fishery collapse coincided with similar declines in catch per unit of effort (CPUE) and abundance of newly molted male snow cra b. In Bonavista Bay, a deep water (>200 m) fishing area north of the A valon Peninsula, CPUE declined less and the proportion of newly molted male snow crab remained relatively constant during the same period. C oincident with the decline of the Avalon Peninsula fishery was a prono unced drop in mean bottom temperature on the commercial fishing ground s, from -0.6-degrees-C to -1.4-degrees-C, a phenomenon not observed in Bonavista Bay. This decline in water temperature appears to have been the cause of the fishery collapse because temperatures became low eno ugh to interrupt the molting cycle of snow crab off the Avalon Peninsu la. If the potential impact of the lower water temperatures and subseq uent long-term cessation of growth and recruitment within the snow cra b population had been recognized, the available pool of commercial-siz ed crab could have been harvested more slowly over a period of years t o lessen the disruption of the fishery.