Age at Maturity, Skipped Spawning, Fecundity, and Site Fidelity of Female Sablefish (Anoplopoma fimbria) during the Spawning Season

This is the first maturity study of female sablefish in Alaska near their winter spawning period.  Skipped spawning female sablefish, fish that have spawned in the past but are not in the current season, were documented for the first time.  Age at maturity was heavily influenced by whether skipped spawners were classified as mature or immature; the age at 50% maturity when skipped spawners were classified as mature was 6.8 years and 9.9 when immature.  Skipped spawning was more common in certain habitats and rates of skipped spawning were higher for older females.  Maturity data is collected annually during the summer. This data has not been used in stock assessment because it coincides with the time when females are developing and are 5-7 months from spawning. The differences in age at maturity between the winter and summer translate to a lower estimate of spawning biomass when maturity is collected in the winter.  Winter collections have provided insight into the implications of using data collected during the summer.  Four female sablefish were satellite tagged during the spawning season.  Although sablefish are highly migratory throughout their lives the limited results indicate that sablefish have site fidelity during the spawning season.