サクラマスの生息密度と産卵床数に基づいた魚道整備による流域連続性の改善効果評価

抄録

Analysis was conducted using data from previous monitoring surveys on fry habitat density and number of spawning beds in the Teshio River basin. The analysis clearly showed that installing and improving fishways in the main stream are effective at increasing the density of fry habitats. It was also clear that installing and improving fishways in the tributaries are effective at increasing the density of fry habitats and the number of spawning beds.

The installation and improvement of fishway in the main stream increased the number of adult masu salmon swimming upstream, helping adult masu salmon to swim upstream where they used to be blocked from going upstream and were forced to spawn at the middle reach-II. The installation and improvement of fishways in the tributaries did not shift the spawning bed and fry habitat areas from the downstream side to the upstream side of the fishway, but it did expand the entire areas.