Life History Traits of a Riverine Population of the Asian Clam Corbicula fluminea

-Monthly collections of Corbicula fiuminea were taken for 1 yr from a small river (depth range 0.1-1.1 m) near Charlottesville, Virginia. Mean densities ranged from 173-2990 clams m2, with an annual mean of 677 clams m2. Based on the time-series of shell-length frequency distributions and from dissections of adults, it appeared that there was one generation produced per year with the first detectable newborns (shell length z 0.4 mm) settling in the substrate during July. Maximum lifespan was 2-3 yr during which clams reached average shell lengths of 11.1 mm in the 1st yr and 17.6 mm in the 2nd yr of life. Other studies have most often reported two generations produced per year with lifespans of 2-4 yr and maximal shell lengths of 30-60 mm. It is suggested that much of the variation in life history displayed by this introduced species in phenotypic.