Growth and overwinter survival of the Asiatic clam, Corbicula fluminea, in the St. Clair River, Michigan

The Asiatic freshwater clam, Corbicula fluminea, is considered a biological contaminant in major US rivers. Samples of C . fluminea were collected from the St Clair River, MI, from April 1986 to April 1987 to investigate their growth and overwinter survival. The reproducing population was found to exist immediately downstream from the Detroit Edison St Clair Power Plant. The increased overwinter loss at sampling locations further from the heated discharge of the power plant suggest that low winter water temperature was the primary mortality agent. Sampling results indicated that the effect of low water temperature may be more severe in the first winter of life than in subsequent winters. The year-round relatively low water temperatures in the St Clair River may limit the growth rate and, subsequently, delay the onset of sexual maturity.