Research Document 1997/58
Factors affecting snow crab year-class strength in the Newfoundland Region
By E.G. Dawe
Abstract
The possible existence of density independent effects on snow crab (Chionoecetes opilio) yearclass strength was investigated utilizing 15 years of trap survey data from each of two NAFO Div. 3L crab management areas. The hypothesis was that water temperature regulates yearclass strength through an effect on development rate and duration of the critical planktonic larval period. This hypothesis was addressed by attempting to correlate survey catch rates of a size group of sublegal sized crabs with upper layer (0-50 m) ocean temperature during their planktonic stage, 7 years earlier. Results suggested that temperature directly affected yearclass strength although favourable temperatures during 1987-89 appeared to be associated with weak yearclasses, perhaps reflecting intervention of density dependent effects. There was no evidence of an effect of predation by fishes.
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