This article reports on the results of a study to determine the species composition and distribution of major invertebrates (clams, snails, and larger crustaceans) in the Blue Earth River system, a major tributary of the Minnesota River. Most significant in the findings, only eleven species remained of the twenty-one species of clams historically found in this river; of these eleven, only three were still common. Included with the article are distribution maps for two of the mussel types studied.
