QUANTIFICATION OF Plecoglossus altivelis USING ENVIRONMENTAL DNA AND TRIAL OF MONITORING OF DOWNSTREAM MIGTATION

Abstract

In recent years, the resource of Plecoglossus altivelis which is the most important fishery target in rivers is decreasing. So it is necessary to grasp the current status of resources and to clarify the factor of decline resources. Environmental DNA (eDNA) analysis is useful tools for clarifying resource dynamics of river organisms. We determined the eDNA concentration of P. altivelis in Saba river and Takatsu river in May, July, October and November to grasp the resource dynamics of P. altivelis. The results of this study shows that P. altivelis was distributed at high density in the downstream in Saba river, and it was distributed at low density in a wide area in Takatsu river. In addition, downstream migration of P. altivelis were confirmed from October to November in both rivers.