GROWTH AND MATURATION OF THE BENTHIC STAGES OF MALE SNOW CRAB, CHIONOECETES-OPILIO (BRACHYURA, MAJIDAE)

Growth and maturation of postlarval male snow crab (Chionoecetes opili o) in an exploited Gulf of Saint Lawrence population were elucidated u sing size distributions in beam trawl samples taken bimonthly from Apr il 1991 to May 1992, moult and maturity indices, and measures of growt h per moult. Males develop in three stages: immature, without spermato phores; adolescent, with spermatophores but undifferentiated chelae; a nd adult, with spermatophores and differentiated chelae. Males change from immature to adolescent after a puberty moult, and from adolescent to adult after a terminal moult producing a final carapace width (CW) >40 mm. The slope of the regression relating post- to pre-moult CW de creases after puberty. Carapace moult increments are the same at pre-t erminal and terminal moults, for a constant premoult CW. Males recruit to the legal size of 95-mm CW at instar XII, approximate to 8.7 years or more after settlement. The slope of the regression of gonad weight on CW is less for adult than for adolescent males owing to the former s' participation in reproduction and to greater depletion of sperm sto res in large than in small adult males. Gonad weight increases with ti me since moult, but for large adults, did not reach levels recorded in prefishery times or in an unfished population.