Variation in the shell form of the swan mussel, Anodonta cygnea (Linea, 1876) in response to water current

A biometric study was conducted on the populations of swan mussel, Anodonta cygnea, belonged to water bodies with different water current velocity (high current: HC; low current: LC). The shell length, width, height, weight and age of the collected mussels were measured. The two groups had different age-classes distributions. The HC mussels had larger mean and maximal values of the biometric parameters. A high and medium correlation coefficient (width-length, height-length, and weight-length) were found in the HC and LC mussels, respectively. The weight-length relationships showed negative allometric pattern (HC: weight=3.6121x0.8561; LC: weight=3.1362x0.8508). The 1-2 years old mussels had the highest rates of increase in length, width and height in both groups. Based on the results, water current velocity influences biometric features and population structure of A. cygnea.