ABDOMEN ALLOMETRY, OVARY DEVELOPMENT, AND GROWTH OF FEMALE SNOW-CRAB,CHIONOECETES-OPILIO (BRACHYURA, MAJIDAE), IN THE NORTHWESTERN GULF OFST-LAWRENCE

Growth and maturation of female snow crab (Chionoecetes opilio) in the northwestern Gulf of St. Lawrence were elucidated using carapace size -frequency distributions, indices of molting activity, ovarian mass, a nd laboratory and field measures of growth per molt. Females develop i n three major stages: immature, with narrow abdomen and no detectable ovaries; prepubescent, with narrow abdomen and previtellogenic followe d by vitellogenic ovaries; and adult, with broad abdomen and reproduct ive capability. Additionally, there is an ephemeral pubescent stage re presented by females temporally close to the maturity molt. A reductio n in the rate of carapace and abdomen growth occurs at the passage fro m immature to prepubescent, because energy is diverted into germinal g rowth, and adulthood is reached at a terminal molt to maturity. The pa ttern of abdomen growth relative to carapace is complex, consisting in successive phases of low, high, and again low positive allometry with increasing size of immature-prepubescent females. Over the period 198 9-1996, a few females became adult at instar VIII at 4.5 years postlar val age, but more commonly, maturity occurred at instars IX and X at a ges of 5.5 and 6.5 years, respectively. Average size at maturity may b e temperature dependent, and within cohorts, larger females may mature earlier than smaller females.