Abstract
We investigated the benthic macro-invertebrate fauna at 40 sites of the Sakawagawa River system of Kanagawa Prefecture, and 391 species belonging to 138 families were recorded. Among them, 6 species were newly recorded in Kanagawa Prefecture. 6 alien species and 11 endangered species were found during this investigation. Numbers of taxa, ASPT (Average Score Per Taxa) values based on Biological Monitoring Working Party (BMWP) adapted for Japan, and EPT (species numbers of the orders, Ephemeroptera, Plecoptera, Trichoptera) indicates that water quality in 40 sites was generally good, and much better in upstream sites. According to the result of TWINSPAN analysis and relationship with the some environmental dates, the Sakawagawa River system can principally be divided into 4 types of river morphology as the case in the Sagamigawa River system.
