The survey recorded five species of freshwater mussels within the CVNRA: Pyganodon grandis , Toxolasma parvus , Potamilis alatus, Utterbackia imbecillis and Fusconia flava . Of these five, Pyganodon grandis is by far the most abundant unionid in the park. This species was found at one site in the Cuyahoga River and appears to be thriving in two ponds, Armington Pond and Horseshoe Pond. In addition, Boy Scouts counted 862 shells of Pyganodon grandis in a 1.5 mile stretch of the drained Ohio & Erie Canal. Based on this information, we estimate that the population in the flooded portion of the canal could number in the thousands. Pyganodon grandis is fairly widespread, but prefers slow moving, quiet water and muddy substrates; the Canal therefore is ideal habitat for this species. Toxolasma parvus was observerd only in the Canal. However, several individuals were found in small pools that formed in the drained bed, which makes it likely that the flooded portion of the Canal is also home to a large population of Toxolasma parvus. This species is a comparatively small mussel, which also prefers slow moving or quiet water and muddy substrates. Divers found Utterbackia imbecillis in Kendall Lake. Utterbackia imbecillis, the paper pondshell, prefers ponds and lakes, or slow, sluggish moving rivers with muddy substrates.
The number of individuals found suggests that, in general, the mussel populations in the Canal and in ponds seem to be in good health. The Ohio & Erie Canal, especially, may be home to thriving populations of at least 2 species of mussels. The status of freshwater mussels in the lower Cuyahoga River is problematic. In addition to Pyganodon grandis, only two individuals of Potamilus alatus and one individual of Fusconaia flava were found alive in the river. The scarceness of these mussels in the river suggests that the Cuyahoga River does not provide adequate habitat or living conditions for unionids. However, the occurrence of any live freshwater mussels in the river can also be seen as a hopeful sign. In June, 1969, the polluted Cuyahoga River made national headlines as it caught on fire. The image of the burning river dramatically highlighted the plight of this nation's waterways. The recurrence of freshwater mussels may be a sign of improving water quality and ecosystem function.