Consequences of Dam Removal on Mussel Assemblages (Unionidae) in the Cuyahoga River

Abstract

ABSTRACT. The primary objective of a new survey of the Cuyahoga River was to assess species richness and population abundance of various mussel species in the family Unionidae throughout the Middle Cuyahoga River and upper parts of the Lower Cuyahoga River. Historically, few records existed for this river between Lake Rockwell and the Cuyahoga Valley National Park, a region in which four dams have been removed in the past 12 years. Timed visual surveys were conducted during low flow conditions and by using tactile techniques in deeper water. Throughout the survey, only 37 live animals were located across the 18 Middle Cuyahoga River sites inspected, which included only Lampsilis siliquoidea, Pyganodon grandis and the state-endangered Ligumia nasuta. No live mussels were found between the Gorge and the Cuyahoga Valley National Park. That 434 shells and valves were collected, and all but two were classified as long dead, attests that mussels had been more abundant, and that at least nine of the ten species known to be present above Lake Rockwell had lived in the Middle Cuyahoga River. Remote sensing data and aerial photographs were used to characterize change in opening up the river, but benefits to water quality and stream flow subsequent to dam removal must be tempered with the apparent loss of an assemblage of mussels better adapted to lentic conditions. Date of Publication: April 2017OHIO J SCI 117(2): 6-15

A multi-spatial analysis and the balanced requirements of freshwater mussels (Bivalvia: Unionidae) and urban inhabitants in the Cuyahoga River watershed

“…assemblage also occurred locally in the West Branch Cuyahoga River where no impoundments are present, and stream species are replacing lentic ones in the Middle Cuyahoga River downstream of the present study, where dams were removed [20]. These changes in water flow therefore suggest a greater role on mussels than land use, which although often reported to vary with mussel abundance [15,42], land use variation failed to provide an explanation of good mussel habitat.…”

“…Many components of the environment impact freshwater mussels, most notably runoff from urban and agricultural areas [13][14][15] that potentially impart increased sediment, nutrient loading and toxins to rivers [16,17]. Habitat change may also include alterations in riparian vegetation, substrate permeability, and water velocity [18][19][20], especially in large rivers [21][22][23]. Mussels cannot move far from the area they deposit as juveniles, and as long-lived species, sustained habitat quality is essential for survival and reproduction [16,24,25].…”

A multi-spatial analysis and the balanced requirements of freshwater mussels (Bivalvia: Unionidae) and urban inhabitants in the Cuyahoga River watershed

“…This response also occurred locally in the West Branch Cuyahoga River and when dams were removed in the Middle Cuyahoga River [19]. Human land use and more impervious surfaces often reduce mussel populations [14,43], but land use failed to provide an explanation here, as…”

“…Many components of the environment impact freshwater mussels, most notably runoff from urban areas and agricultural [12][13][14] that impart increased sediment, nutrient loading and potentially toxins to rivers [15,16]. Habitat change may also include alterations in riparian vegetation, substrate permeability, and water velocity [17][18][19], especially in large rivers [20][21][22].…”