Local and large-scale environmental conditions can affect maternal investment, larval growth and recruitment of rockfish (Sebastes spp.) in the Southern California Bight

Rockfishes (Sebastes spp.) are economically and ecologically important species in the north Pacific, however, by the late 1990s many species were overfished. Within the Southern California Bight, several rockfish species are currently rebuilding, and it is important to discern factors affecting their population dynamics. Although year-class-strength in rockfishes correlates with upwelling and productivity, we don’t yet understand many of the underlying mechanisms that drive recruitment. We test the hypotheses that maternal investment (MI) and larval growth rate (RG) predict recruitment success for multiple rockfishes and that these factors are influenced by intra- and inter-annual environmental conditions.

We quantified MI and RG for 8 rockfishes (5 targeted by fishing) by analyzing larval otoliths collected from 1998 to 2013 by the CalCOFI program. We evaluated potential environmental effects modeling mean MI and RG per year against mean temperature, salinity and chlorophyll in the upper 100m in the summer/fall prior to spawning and at the time of sampling, respectively. Preliminary results indicate that large-scale and local environmental conditions can affect growth, condition, and abundance of all studied species. RG increased when local oceanographic conditions favored high primary production (low temperature, high chlorophyll a, high salinity). Basin-scale factors such as ENSO significantly influence local condition dynamics. On a finer scale, SST, salinity, and chl acorrelated with species-specific differences in larval size-at-age and condition. We demonstrate that environmental conditions experienced by larval rockfishes influence their capacity to survive to the pelagic juvenile stage. As ocean conditions continue to change, understanding the underlying cause of recruitment variation is integral to the continued success of rockfish recovery, ecosystem function and fisheries management.