Effects of spatial and temporal changes in water velocity on the density of the freshwater snail Potamopyrgus antipodarum (Gray)

The effects of spatial and temporal changes in water velocity on the introduced freshwater snail Potamopyrgus autipodarum (Gray) (Gastropoda: Hydrobiidae) were studied in an artificial stream and in Main Creek, Victoria, Australia. The water velocity at which P. antipodarum became dislodged in the artificial stream was in agreement with their distribution in Main Creek. In Main Creek the density of P. antipodarum on a standard subs trate (half bricks) was negatively correlated with water velocity. However, no evidence was found that increases in water velocity associated with floods affect the densities of P. antipodarum.