Habitat selection and movement by individual cutthroat trout in the absence of competitors

If salmonids attempt to optimize their energy gain, then one could assume t hat all fish with knowledge of a particular environment would occupy the sa me habitat if it were not already occupied by a competitively dominant indi vidual. We attempted to determine whether individual cutthroat trout introd uced at separate times would select the same channel units within sections of stream when all larger trout were removed from those sections. Cutthroat trout disproportionately used pools, but not to the exclusion of riffles d espite the absence of larger fish. In only one of seven sections did differ ent cutthroat trout select the same channel unit throughout the study. In t he remaining sections, they did not consistently occupy the same channel un it. We believe that incomplete knowledge of the available habitat, or littl e difference in food availability among a few habitats, may have caused the lack of consistent habitat selection.