2023 Volume 79 Issue 27 Article ID: 23-27003
There is no definitive agreement about the appropriate geometric form and hydraulic conditions of eel ladder. At present, it has been recognized utility of bunches of brushes, mesh mat, boulders and cylindrical protrusions as the material of eel-ladder bottom, but it is not cleared that which material is the most suitable for Anguilla japonica migration. In this study, it attempted to clarify the effect of varying material of eel-ladder bottom and discharge on migration characteristics of Anguilla japonica. It was found that migration and migration success rates were higher in the case of cylindrical protrusions. On the other hand, those rates were the lowest in the case of bunches of brushes. It is assumed that Anguilla japonica can rest by wrapping body under the condition of cylindrical protrusions. Therefore, it is suggested that the best material of eel-ladder bottom is cylindrical protrusions for Anguilla japonica migration.
