2021 Volume 87 Issue 2 Pages 132-143
Growth of the brackish water bivalve Corbicula japonica in Lake Abashiri was assessed by analyzing the age and shell length composition of individuals captured in field sampling and reared through a field-caging experiment for the 2008 year class. The specific growth rate (SGR), growth model, and length frequency distribution at each age were calculated in relation to shell length. The growth rate of bivalves was high from June to September, when the water temperature was over 15℃. Because of the seasonal growth pattern, the von Bertalanffy growth model extended with a periodic function was determined as the best model when our data in the field-caging experiment were applied to several growth models. It was found that the growth of C. japonica in Lake Abashiri is markedly slower than that in other fishing grounds in Honshu during the initial stage to age 2, and is accelerated in summer when aged 2-3. In Lake Abashiri, fast-growing individuals reach commercial size (≥23.3 mm in shell length) at age 4, whereas most individuals take 5 or 6 years to grow to that size.
