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News Release

Clubshell and Northern Riffleshell Augmentation in Illinois



Jody Millar (309)757-5800, ext. 202


Steps Proposed to Save Endangered Mussels

Two endangered freshwater mussels – the clubshell and the northern riffleshell – may get a boost as the U.S. Fish and Wildlife Service considers releasing the species into Illinois’ Vermilion River Basin, under a draft Environmental Assessment developed by the Service. 


Both mussels were listed as endangered in 1993 and were believed to be gone from Illinois until discovery of a live clubshell in 2000.  The Service is exploring options for releasing clubshells and riffleshells into suitable habitat as one of a number of ongoing efforts to recover the two species.


In the draft assessment, the Service outlines four alternatives for enhancing populations of the two species, ranging from no action to augmenting existing populations and establishing new populations through release of wild or captive-propagated mussels.  The Service has identified a preferred alternative which calls for releasing clubshells to augment existing populations in Illinois, and reintroducing the two species to establish new populations of both the clubshell and riffleshell in their historic range in Illinois. 


The clubshell was once found from Michigan to Alabama and from Illinois to West Virginia.  The northern riffleshell occurred throughout the Ohio River Valley and north into Michigan.  Both species’ populations have declined dramatically throughout their range due to declining habitat quality. 


Mussels are sensitive to silt, pollution from agricultural run-off and industrial wastes, construction of dams and impoundments; they also are threatened by competition with the non-native zebra mussel.  Many consider mussels important indicators of water quality in the rivers and streams that support both human and wildlife communities.
Because of the mussels’ rapid decline and highly isolated populations, the Service believes augmenting clubshell and riffleshell numbers will be an essential tool in upgrading their status to threatened, and eventually, in recovering the two species.


The Service’s draft Environmental Assessment is available at http://www.fws.gov/midwest/endangered.  Comments about the alternatives outlined in the draft may be submitted to Jody Millar, U.S. Fish and Wildlife Service, 1511 47th Avenue, Moline, IL  61201, or via email to riffleclubEA@fws.gov  by August 8, 2008.  The Service will select an alternative within 30 days after the comment period has closed.


For more information on freshwater mussels in the Midwest, visit www.fws.gov/endangered


The mission of the U.S. Fish and Wildlife Service is working with others to conserve, protect and enhance fish, wildlife, plants and their habitats for the continuing benefit of the American people. We are both a leader and trusted partner in fish and wildlife conservation, known for our scientific excellence, stewardship of lands and natural resources, dedicated professionals and commitment to public service. For more information on our work and the people who make it happen, visit www.fws.gov.


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Last updated: September 21, 2016