Seasonal Habitat Use and Productivity of Commercially Important Rockfishes in the Gulf of Alaska

Our understanding of EFH for many rockfish species in the Gulf of Alaska (GOA) is rudimentary, especially their seasonal habitat requirements and the importance of specific habitat types. We examined the seasonality of rockfish distribution, abundance, and productivity across three habitat types: low relief, high relief rocky/boulder, and high relief coral/sponge. Research cruises were conducted during the summer, winter, and spring at two study sites in the central GOA, focusing on three commercially important rockfish species (Pacific ocean perch, Sebastes alutus, northern rockfish, S. polyspinis, and dusky rockfish, S. variabilis). In each sampling period, we used an underwater stereo drop camera system to examine rockfish habitat associations, community structure, size structure and density within each habitat type and a bottom trawl and bongo net to collect fish and zooplankton. We collected specimens to examine differences in reproductive potential among the habitats in each season. Preliminary CPUE estimates of rockfish density from the video drops indicate significant differences in rockfish density among habitats, with highest densities in high relief habitats. This research will enable us to better understand the relative importance of particular habitats to rockfish productivity throughout the year and provide data critical for understanding EFH for these species.