Spawning Omission and the Productivity of Deepwater Rockfish in the North Pacific Ocean

Recent examination of the maturity of three deepwater rockfish species (shortraker rockfish, Sebastes borealis, rougheye rockfish, S. aleutianus, and blackspotted rockfish, S. melanostictus) in the Gulf of Alaska revealed a high proportion of mature individuals were skip spawners. The proportion of skip spawners varied among species but at least 30% of individuals determined to be adults were undergoing spawning omission during the upcoming reproductive season and in at least one species the prevalence of skip spawners was related to size. Specimens for this study were primarily collected during the 2010 reproductive season in the central Gulf of Alaska and additional data are needed to determine the consistency of skip spawning across various temporal and spatial scales. The presence of non-spawning mature fish will influence the stock assessment results for these species. Using a simulation model based on the life-history and assessment of the blackspotted-rougheye rockfish complex we examined how the presence of skip spawners impacts estimates of spawning biomass and recommended catch limits for these species.