AGE-AT-MATURITY ESTIMATES FOR ATLANTIC COAST FEMALE STRIPED BASS

This study was undertaken to estimate the percentage of mature female striped bass Morone saxatilis present in each age-class during annual coastal feeding migration. Migratory striped bass (N = 302) were sampl ed in coastal Rhode Island waters during spring (May-June) and fall (S eptember-November) from 1985 to 1987. Stocks were identified by analys is of morphometric characters and isoelectric focusing of eye-lens pro teins. Histological sections of ovarian tissue were used to categorize maturity state. Fish were considered mature if a class of oocytes mea suring at least 150 mum and containing cytoplasmic inclusions was foun d in the ovarian sections. All females whose age at next potential spa wning was 7 and older were mature. Our empirical observations indicate d that 12% of fish in age-class 4, 34% of fish in age-class 5, and 77% of fish in age-class 6 were mature. The estimate of the proportion of mature fish in age-class 5 differs significantly from that of Merrima n (1941), who also examined coastal migrants. No significant differenc es were found in maturity estimates of fish from stocks of different o rigin.