Crustacean community composition and trophic use of the drift vegetation habitat by juvenile splitnose rockfish Sebastes diploproa

The community composition and trophic use of the drift vegetation habitat by pre-settlement juvenile splitnose rockfish Sebastes diploproa was documented in June, August, and October 1992 in the San Juan Archipelago, Washington, USA. Fucus spp., Zostera spp. and Nereocystis luetkeana were the dominant vegetation for the months sampled. Juvenile S. diploproa collected from the drift vegetation habitat fed mainly on planktonic organisms, including copepods and cladocerans, during June and August. In October, diets shifted to larger epiphytic prey and were dominated by 1 amphipod species. Of 5 major prey taxa, 3 had significantly different densities in drift vegetation and nearby open water habitats. Prey taxa were not dominant in the drift vegetation habitat in June and August, indicating a high degree of prey selection during these months. In October, dominant prey taxa made up a large proportion of the crustacean community in the drift vegetation habitat and less prey selection occurred. Community indices of the drift vegetation habitat were up to twice as high as those of the adjacent open water habitat for the 3 mo sampled due to vegetation associated crustaceans. Drift vegetation provides nearshore habitat features to pelagic systems. It provides food, refuge, and possibly transport from offshore to nearshore habitats for a number of recreationally and commercially important species.