An update of mussel populations throughout the upper Cuyahoga River watershed

Ohio Journal of Sciences (abstr.) 118: The Cuyahoga River is one of America’s heritage rivers, the former poster-child for the Clean Water Act (1972), and in the upper reaches, part of Ohio’s Scenic River program. As such, the Cuyahoga River has been one of the most protected streams in the country since the 1970s. Water quality is now within acceptable limits outlined by Ohio Environmental Protection Agency, shoreline integrity has increased throughout the watershed, and sediments mostly test free from toxins and heavy metals. With water quality recovery, freshwater mussels (family Unionidae) were expected to increase in the upper Cuyahoga River or at least sustain abundance and richness levels reported in the 1990s. To test for levels of change, timed surveys of 2 person hours were made at 25 sites chosen based on proximity of roads or foot paths along the river in 2012 and these surveys were repeated using the same approach in 2016. However, only 389 mussels of 8 species were found in 2012 and just 111 of 4 species in 2016. These results present a declining trend and significant losses at many sites based on categorical analysis of binomial probabilities. Mapping relative abundance against the physical habitat suggested that the decline of freshwater mussels is a complex problem that may involve impoundments, flow dynamics below dams, and sediment stability. Restoring natural flow regimes, in addition to protecting habitat, are critical to support successful reproduction and survival in this imperiled fauna moving forward.