Fingernail clams are also bivalve molluscs, but are not closely realated to freshwater mussels. Fingernail clam shells and live specimens were collected from ponds, the Cuyahoga River, and tributaries. One other bivalve, the introduced Asiatic clam, Corbicula fluminea, is locally abundant in the park. It is found particularily in the Cuyahoga River.