Variability in rockfish (Sebastes spp.) fecundity: species contrasts, maternal size effects, and spatial differences

Abstract

Over 60 species of rockfish (Sebastes spp.) reside off the coast of California, many of which are economically important to both recreational and com- mercial fisheries. Rockfish are live-bearers with a di- verse array of reproductive strategies. Understanding thereproductivepotentialofanexploitedstockiscritical to assessing the health and status of a fishery. We inves- tigated the reproductive ecology offour rockfish species to examine species contrasts and to determine spatial and maternal-size effects on reproductive potential. Females were sampled during the winter parturition season (November through March) of 2009 through 2012. Maternal length and somatic weight were posi- tively correlated with relative fecundity (larvae per g somatic weight) in all four species, indicating a dispro- portionately greater reproductive output by larger, older females. Fecundity estimates in Chilipepper, S. goodei, and Yellowtail rockfish, S. flavidus ,v aried regionally, but did not significantlydiffer overtimewithinthe years sampled (sample sizes for Speckled, S. ovalis ,a nd Blackgill rockfish, S. melanostomus, were too small to allow spatiotemporal comparisons). Two reproductive strategies were evident as Yellowtail and Blackgill rockfish produced a relatively highly fecund, single brood of smaller-sized larvae annually, in contrast to Chilipepper and Speckled rockfish, which produced larger-sized larvae with lower fecundity. In some re- gions multiple broods were common, complicating es- timates of annual fecundity for these two species. There was some evidence that egg production was positively correlated with female condition, indicating that envi- ronmental variability in oceanographic conditions and productivity may drive changes in fecundity and repro- ductive strategy (i.e., single versus multiple broods).