Sex ratio, spawning period, and size and age at maturity of sablefish Anoplopoma fimbria off Northern California

Size, sex, state of maturity and age were determined for sablefish captured by commercial otter trawl vessels at depths from 100m to 900m off northern California from January through August 1984. Sex ratios appeared to be 1:1 among immature fish at all depths, but significantly departed from a 1:1 ratio among mature fish during many months and at many depths, without any clear pattern. Plots of percent spent fish against month suggested that spawning took place from late January through March with a probable peak during early February. Estimated fork lengths at 50% maturity showed a shift to a smaller size with increasing depth. A greater fraction of males and females was mature at smaller sizes and younger ages in deeper waters (>600m) than in shallow waters (