加古川市街の農業用水路における貝類の分布と水環境

Habitat distribution of shellfishes were investigated about Semisulcospira libertina(S.L), Cinotania Mstrica(CH) and Corbicula leana(CL) in the two agricultural canals which are neighboring and have same source of stream. As a result of detailed environmental researches, it was found that the habitat distributions of these shellfishes were different considerably between these two canals. We predicted that speed of stream was main factor of this difference. This prediction was supported by a series of experiments by using an experiment waterway of our college. S.L. can inhabit the wide area of agricultural canal because they do not need substratum such as sand and silt, but they can not stay at more than 50cm/s of flow. It was found that C.H. and C.L. need the substratum for their habitation, a 40cm/s of flow becomes the limit for them because substratum begin to drift from this condition. A series of results obtained in the experiments of waterway accorded with the results of field investigations