THE REPRODUCTIVE CONDITION OF WHITE STURGEON, ACIPENSER-TRANSMONTANUS, IN SAN-FRANCISCO BAY, CALIFORNIA

White sturgeon, Acipenser transmontanus, adults (n=855) were collected on their feeding grounds in San Francisco Bay, California, and their sex and stage of sexual maturity were evaluated histologically. They d id not exhibit-external sexual dimorphism, and the overall sex ratio d id not differ from 1:1. Average fork length was 139 cm +/-1.1 cm (mean +/- standard error of the mean); females were longer (145 cm +/-1.2 c m, n=443) than males (133 cm +/-1.0 cm, n=412). In smaller size classe s (less than or equal to 115 cm), males were significantly (P<0.05) mo re numerous than females. The proportion of females, however, was sign ificantly higher among larger fish (>155 cm). The sample of females co nsisted of 70% fish with ''immature'' (previtellogenic) ovaries, 12% w ith ''maturing'' (vitellogenic) ovaries, and 18% with ''ripe'' (large, pigmented eggs) ovaries. In contrast; most males were either ''maturi ng'' (meiosis, 56%) or ''ripe'' (spermatozoa, 39%). Ripe females repre sented only 9% of all fish sampled. Egg production by females, estimat ed by hatchery spawning, averaged 5,648 eggs/kg of body weight. The le ngth at which white sturgeon in San Francisco Bay attain sexual maturi ty was estimated to be 95-135 cm in females and 75-105 cm in males. Th e duration of one ovarian cycle in iteroparous females was estimated t o be longer than one year, with an apparent 2- to 4-year interval betw een spawning periods; the reproductive cycle of males was estimated to be 1-2 years. The low reproductive potential of white sturgeon in San Francisco Bay should be considered in fishery management of the speci es.