An exploration of factors that relate to the occurrence of multiple brooding in rockfishes (Sebastes spp.)

Abstract

The phenomenon of multiple brooding, the production of more than one brood within a reproductive season, is a poorly understood process in rockfishes (Sebastes spp.). Most species produce a single brood, and all stock assessment models for Sebastes species assume the reproductive output (fecundity) of a single annual brood. We evaluated how well this life history trait could be predicted by both oceanographic (mean latitude, ocean temperature, dissolved oxygen levels, and depth) and demographic (maximum length, maximum age, and natural mortality rate) factors for 24 species of rockfish found on the continental shelf along the West Coast of the United States. Our results indicate that multiple-brooding species are considerably more common in lower latitudes (32–36°N) or in warmer waters (>9°C at depth) and that the other environmental and demographic factors analyzed were not empirically informative. This work provides a more comprehensive understanding of the reproductive ecology of shelf rockfishes, could contribute to assessments of climate change vulnerability, and should eventually lead to improvements in stock assessment models for economically and ecologically important rockfishes.