2023 Volume 46 Issue 3 Pages 69-75
The dependences of the filtration and respiration rates of a freshwater bivalve in Lake Biwa, which was inferred to be Corbicula leana, on water temperature and dissolved oxygen (DO) concentration were determined through cultivation experiments and literature survey to evaluate its habitable condition. The filtration rate of the bivalve with a shell length of 14.9 ± 1.2 mm depended on water temperature and DO concentration. The effect of water temperature on filtration rate was modeled as an exponential function with a high-temperature inhibition and the optimal temperature was evaluated to be 20.8 ℃. The filtration rate reached a plateau at a DO concentration above 4 mg L−1 and decreased at a DO concentration of 2.6 mg L−1. When the feed concentration at the bottom of the southern basin of Lake Biwa was assumed to be 3 mg-C L−1, the growable temperature range of the bivalve was estimated to be 12.1–26.6 ℃ at the DO concentration ≥ 4 mg L−1. The annual growth rate of the bivalve was estimated to decrease by 0.005–0.01 g-C y−1 indiv.−1 with a 1 ℃ increase in water temperature. Thus, lake warming was considered to negatively affect the bivalve population in Lake Biwa.
