Ref ID : 7091
Yasuda Kaori and Okino Tokio; Distribution and Seasonal Changes of Aquatic Oligochaeta in Lake Suwa. Jap.J.Limnol. 48(1):1-8, 1987
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Ten species of aquatic Oligochaeta were identified in Lake Suwa. Limnodrilus hoffmeisteri and Limnodrilus claparedeianus were obtained from every station and were most abundant among all species. Their density tended to be high as the depth was greater. The second abundant species, Rhyacodrilus sp., was collected in the region shallower than 4 m depth. The study on the seasonal changes in the density of Limnodrilus spp. (L. hoffmeisteri and L. claparedeianus) and Rhyacodrilus sp. exhibited clearly a decrease in summer and an increase winter and spring. Lake Suwa was divided into three regions in terms of the depth distribution of aquatic Oligochaeta, namely, the region deeper than 5 m depth, the transitional region from 3 to 4 m depth, and the region shallower than 2 m depth. The seasonal changes in the density and depth distribution of aquatic Oligochaeta were discussed from the enviromental condition of the lake bottom and the reproductive state.