||Effects of slopes and spaces of protrusions in fish ladder for eels on migration rate of Anguilla japonica
Onitsuka, K. ,
Akiyama, J.Izumi, K.
11th Pacific Symposium on Flow Visualization and Image Processing
2017-12 , 11th Pacific Symposium on Flow Visualization and Image Processing(PSFVIP-11 )
In recent year, populations of Anguilla japonica have been decreasing sharply. This decrease is partly because it is estimated to be overfishing of Anguilla japonica, the deterioration of the river environment and so on. Migrating fishes are impeded by weirs and dams in the river. Fishways have been constructed to swimming fish like Plecoglossus altivelis altivelis in order to solve this problem. On the other hand, it is thought that special fishway is necessary for demersal fish like eels. Furthermore, studies on fish ladder for eels haven’t been conducted. In the present study, an investigation on migration rate of Anguilla japonica was conducted under the condition that slope of fish ladder for eels and spaces of protrusions are changed. It was found that migration rates decreased with the increase of slopes and spaces of protrusions. Besides, Anguilla japonica migrated while using protrusions by serpentine movement.
The 11th Pacific Symposium on Flow Visualization and Image Processing, 2017, 1-3 December, Kumamoto, Japan