Description of the habitat used by dusky rockfish (Sebastes ciliatus) in the Gulf of Alaska based on the analysis of the spatial distribution, geographic distribution and associated species assemblages using commercial fishing and research survey bottom trawl data will provide information useful for understanding their ecology. Use of historical data such as those collected during commercial fisheries and research surveys is a good preliminary step at describing the habitat of dusky rockfish. Analyses used in the description of fish habitats include the use of numerical classification and multivariate statistical analyses. These techniques can also be utilized using a Geographic Information System (GIS) to view any geographical dependency in the data. The results from these analyses will ultimately be useful in creating more ecosystems based fishery management plans.
Geographic analyses of the data from the commercial fishery resulted in illustrations of the possible geographic dependency of high densities of dusky rockfish. These areas of high densities are also related to sub-tidal geologic features such as troughs and gullies. The results from the geographic analyses of the research survey data were, for the most part, inconclusive. These results may provide further evidence that the surveys of the Gulf of Alaska do not adequately sample rockfish habitat. Furthermore, commercial fishery and research survey data should be used together when analyzing commercially important species to provide a balance of species specific and non-specific data.