WHAT WE KNOW ABOUT FISH ASSEMBLAGES AROUND THE DEEPWATER PRODUCTION PLATFORMS OF SOUTHERN AND CENTRAL CALIFORNIA

Abstract

In 1995–97, we surveyed the fishes living on and around seven offshore oil platforms in the Santa Barbara Channel region using the research submersible Delta. The bottom depths of these platforms ranged from 49 to 224 m. We found that the fish communities differed among platforms and that there were several distinct differences in the fish assemblages living in the midwater and bottom habitats around all of the platforms. Both midwater and bottom assemblages were dominated by rockfishes. Platform midwaters were comprised of young-of-the-year or juveniles up to two years old. The fish communities around the bottoms of the platforms were dominated by larger individuals, primarily subadults or adults. The total fish biomass was much greater on the bottoms, due to the larger fishes living there. There was a consistently greater number of species on the bottom compared to the midwater of each platform, likely due to a larger variety of habitat types on the bottom. We found significantly higher densities of young-of-the-year rockfishes around platforms north of Pt. Conception compared to those in the Santa Barbara Channel.