| To assess effects of sediment addition from the sediment bypass tunnel of the Koshibu Dam, the main gut contents of an omnivorous fish, Japanese dace (Tribolodon hakonensis) were compared between before and after the sediment addition in impacted (Koshibu River) and reference (Toyama River) rivers.In the impacted river (Koshibu River), the main gut contents mainly consisted of algae before the sediment addition but increased ratio of aquatic insects after that. In the reference river (Toyama River), the main gut contents consisted of aquatic insects mainly both before and after the sediment addition. Accordingly, the changes in the main gut contents (from algae to aquatic insects) by the sediment addition can be considered as a positive effect although its mechanism should be examined in the further study. |
