Knowledge of species abundance, diversity and distribution are most important information for ecosystem conservation and management. In this study, we revealed fish communities of three A class rivers in Chugoku district using environmental DNA (eDNA) method. Furthermore, we compared fish community between eDNA and conventional National census. We also evaluated the reproducibility of eDNA method against National census. From the results, the reproducibility of eDNA was higher in freshwater area but lower in blackish area. In freshwater area, reproducibility of eDNA was increased by sampling at multiple river environment than at single site. Environmental DNA method enables to detect the fish community efficiently, however, it is more important to set sampling site in consideration of environmental compartment for uncovering fish community in blackish and complicate river environment.
