Habitat associations of demersal fishes and crabs in the PribilofIslands region of the Bering Sea

摘要

Habitat associations of demersal fishes and crabs were determined from observations of videotapes recorded by a camera-equipped remotely operated vehicle (ROV) in the Bering Sea near the Pribilof Islands in September 1995 and 1997. We identified 42 taxa representing 16 families of fishes and 8 taxa from 3 families of crabs. Families Pleuronectidae (righteye flounders) and Cottidae (sculpins) were represented by the greatest number of taxa. Lepidopsetta polyxystra and Chionoecetes opilio were the most frequently observed fish and crab species. Other fish species in the families Pleuronectidae, Gadidae, Scorpaenidae, Agonidae, and Bathymasteridae were also encountered frequently. Six classifications based on substrate and cover were used to describe the habitat where each fish and crab was observed. Agonids and pleuronectids were typically observed on silt, mud, or sand substrate with no cover while other taxa, particularly cottids and bathymasterids, were encountered in more varieties of habitat including areas covered with rocks and boulders. Significant differences in species composition were found among habitats and stratified depth ranges. Similarity analyses showed that different taxa were responsible for these differences, but within each habitat type and depth range, two to five species contributed to 90% of the average similarity. Some ROV dives were paired with bottom trawls in the same general locations. Species compositions of the ROV observations were significantly correlated with that of the corresponding bottom trawl catch compositions. Overall, we believe that in situ observations provide useful information on fish habitats and behaviors not readily available from conventional trawling surveys.