Life history and population dynamics of the exotic snail Potamopyrgus antipodarum (Prosobranchia: Hydrobiidae) in Lake Purrumbete, Victoria, Australia

The density, population size-structure, and fecundity of the exotic snail Potamopyrgus antipodarum are described, for a period of two years, on two shores subject to different levels of disturbance in Lake Purrumbete. The population dynamics of Potamopyrgus antipodarum showed the same seasonal pattern in the numbers of embryos carried per individual female in both years, but seasonal patterns in density and potential reproductive output of the population differed between shores. Densities of Potamopyrgus antipodarum were high, with a trend for highest densities to occur in spring and summer. The population consisted almost entirely of females, which is indicative of a parthenogenic mode of reproduction. Fecundity was high, with the number of embryos carried per female peaking in spring. In summer, the population was dominated by small individuals, but some small snails were present at all times of the year. Potamopyrgus antipodarum was found to be a very successful invader of Lake Purrumbete, with high densities, high fecundity, parthenogenesis and the presence of embryos throughout the year contributing to this success.