ウナギ用魚道の傾斜と突起物の間隔がウナギの遡上特性に及ぼす影響

抄録

Populations of Anguilla japonica have been decreasing in recent years. The reasons of the population decreasing are overfishing of Anguilla japonica, the deterioration of the river environment and so on. Even among them, there are problems that weirs and dams in the river impede migration of fish. For this problems, fishway has been constructed. However, particular fishway is needed for demersal fish like eels. Besides, studies on fish ladder for eels haven’t been conducted. In this study, an investigation on migration rate of Anguilla japonica was conducted under the condition that slope of fish ladder for eels and spaces of pro-trusions are changed. It was found that migration rate decreased with an increase of slope and spaces of protrusions. Besides, Anguilla japonica migrated while using protrusions by serpentine movement.