岐阜県庄内川水系土岐川における天然遡上アユの確認

抄録

Due to multiple weirs constructed in the Shonai River (lower reach of the Toki River), local belief held that ayu (Plecoglossus altivelis altivelis) migration was impeded, local fishery cooperatives therefore managing ayu by seed stocking in the Toki River. However, individuals collected upstream from the Shonai River weirs, their origins discriminated using otolith morphological abnormalities and microchemical analysis, included two that were clearly amphidromous, such being evidence of migration.