A New Technique for Estimating the Abundance and Habitat Use of Stream Fishes

ABSTRACT

An open-sampling technique that employed seining and AC electroshocking with a downstream block net was compared with enclosure sampling in a small river. Relative abundance of species, species diversity and richness, total numbers and densities of fish, and median fish size were examined. The two sampling techniques provided concordant fish-assemblage patterns for riffles and runs. Pool samples showed differences in species diversity and/or dominant species between sampling methods, which resulted from fish mobility or sample bias. Fish size did not differ significantly between the two methods, and only runs showed noticeably higher fish densities for the enclosure samples.