Freshwater Mussels (Bivalia: Unionidae) of the Wakarusa River Basin

Sixty years have past since the last extensive freshwater mussel (Bivalvia: Unionidae) survey of the Wakarusa River basin.During that time, the basin has experienced substantial changes, including construction of a reservoir and expansion of several urban areas.To determine what changes might have occurred in the freshwater mussel assemblage since the last survey, I sampled freshwater mussels by hand grabbing in a haphazard manner at 28 sites in the summer of 2004.Of the 27 species historically known from the basin, I collected 39 live individuals of nine species in 52 man-hours, including one Truncilla donaciformis, which is listed as species-in-need-of-conservation (SINC) by the state of Kansas; I also collected valves of an additional four species.Six sites had live individuals, and valves were found at an additional ten sites.I did not find the nonindigenous zebra mussel Dreissena polymorpha, which recently has become established in Kansas in the Walnut River basin.