Abstract

Potamopyrgus antipodarum is world wide invasive species with established populations in Europe, Australia, Japan, and, most recently, North America. Potamopyrgus was first found in Lake Ontario and the St. Lawrence River in 1991. The purpose of this study was to determine the effect of depth on population densities and the relationship between Potamopyrgus and other mollusk species in Lake Ontario. A ponar dredge was used to gather sediment from Lake Ontario, near Wilson, NY along three transects in 2004 and 2005. Dredging was done at 5 meters in depth and continued at 5 meter increments until 45 meters in depth was reached. Potamopyrgus was found in depths between 10 and 40 meters; with a peak density between 15 and 25 meters. Preliminary results suggest that there is little overlap between Potamopyrgus and native mollusks suggesting that competition may be an important factor influencing the distribution of this invasive species.