The reservoir also becomes a killer for fish that normally migrate. Because the migration path of the ayu sweetfish (Plecoglossus altivelis) has been cut off by the reservoir, the species 'population has plummeted.
水庫也成為具洄游特性魚種的殺手，台灣香魚的洄游通道就因被水庫截斷，導致族群驟減。