Abstract
The abundance of N. lutrensis and presence-absence of 8 midwestern fishes are quantified on environmental gradients identified by principal components analysis of conditions at 101 field localities in 8 states [USA] at which collections were made in one 35-day span of 1978. Although all species included in the analysis have large geographic ranges, they differ in their patterns of distribution, ranging form "rare-specialists" to "common-generalists" in this analysis, and in distribution across the suites of environmental conditions which are considered to define multivariate environmental space. The environments of the species identified by principal components analysis agreed with and supported the relatively subjective autecological descriptions of species habitats found in standard reference works, providing mutual support for both approaches to evaluating ecology of fishes.