The distribution of the invasive New Zealand mud snail (Potamopyrgus antipodarum) in streams in the Lake Ontario and Lake Erie watersheds

The invasive New Zealand mudsnail, Potamopyrgus antipodarum, is a small freshwater hydrobiid snail with populations in western US rivers and streams and in the Laurentian Great Lakes. The snail has had established populations in the Great Lakes since at least 1991 and in one stream emptying into Lake Ontario since at least 2007. This study’s purpose was to broadly survey streams and rivers emptying into Lakes Ontario and Erie to determine the extent of the species’ lotic invasion in the Eastern US. In the summer of 2011, over 100 sites were sampled from the Niagara River, NY to Oswego, NY along Lake Ontario and over 80 sites from Buffalo, NY to the Pennsylvania-Ohio State line along Lake Erie. At each site, general observations of the stream were made and the organisms living in the stream were surveyed for the presence of New Zealand mud snails. Potamopyrgus was found at the site of original discovery and at one additional location along Lake Ontario. In addition an unusual snail was discovered that was a hybrid between a native species (Pleurocera livescens) and an invasive (Pleurocera virginica). This hybrid was extremely abundant in several locations and may be invasive.