The reintroduction of the northern riffleshell (Epioblasma rangiana) and clubshell (Pleurobema clava) in Illinois


Beginning in 2005, the INHS partnered with the Illinois Department of Natural Resources, the U.S. Fish & Wildlife Service (USFWS), and state agencies in Pennsylvania and Ohio to implement portions of the USFWS’ recovery plan for the Northern Riffleshell (Epioblasma rangiana, bottom left of picture) and Clubshell (Pleurobema clava, upper right of picture).


Northern Riffleshell and  a clubshell

Both species are federally endangered and were historically present throughout the Ohio River drainage, including the Vermilion River of the Wabash. Their range-wide declines were not attributed to one problem, but rather a combination of issues that reduced habitat and water quality, including impoundments, siltation, pollution, stream dredging, and exotic species.




A salvage project in Pennsylvania on the Allegheny River provided an opportunity for the translocation of Northern Riffleshells and Clubshells into Illinois. The Hunter Station Bridge, which passes over the largest known populations of these two species, is scheduled for removal in 2018. It is estimated that this bridge project would directly impact nearly 100,000 mussels.  Since 2010, nearly 4,200 Northern Riffleshell and 3,700 Clubshell have been translocated to the Salt Fork Vermilion River and Middle Fork Vermilion River.  Both of these streams have multiple areas in conservation ownership and support diverse and highly-valued mussel assemblages and populations of the known fish hosts.  The goal of this project is to re-establish self-sustaining Northern Riffleshell and Clubshell populations into their historical ranges in Illinois, and to determine the viability of translocating endangered mussels displaced by bridge construction projects. This relocation project is being funded, in part, by a natural resource damage assessment settlement (Hegeler Zinc — Lyondell Basell Companies) to the U.S. Fish and Wildlife Service and to the State of Illinois.