The ecology of the zebra mussel (Dreissena polymorpha) in the lower Great Lakes of North America: I. Population dynamics and growth

Five populations of Dreissena polymorpha from three lakes (Lake Sr. Clair, Lake Erie, and Lake Ontario) in the lower Great Lakes Region were examined from 1992 to 1994 to determine the population dynamics, reproductive cycle, secondary production, and the allocation of resources to somatic tissue, s hell, and gamete production. In this paper data are presented on the popula tion dynamics, including demography and density, and variation in shell len gth, somatic tissue, and gonad weight. There was much variation in life spa n, density, and growth among sites, however, variation was much greater amo ng sires in different lakes. The lifespan of D. polymorpha was estimated be tween 2 and greater than 4 years, depending on the site. Growth in shell le ngth was related so food supply, temperature, and the age structure of indi viduals at a given site. Shell growth of year one individuals ranged from 0 .5 mm to 11.2 mm. There was no correlation between somatic tissue growth an d gonad tissue growth, suggesting differential allocation of resources.