2022 Volume 78 Issue 2 Pages I_823-I_828
In Japan, there are many pool-type fishways that have two migration routes such as notch and orifice. However, the conditions of use and the appropriate placement of orifice for Anguilla japonica are unknown. In this study, the vertical position of orifice was varied from 0 to 0.25m from the bottom of the pool, and the flow velocity in the orifice was varied from 0 to 7(1/s) to investigate the migration characteristics of Anguilla japonica. The results showed that Anguilla japonica could migrate under all conditions within the experimental range and the migration rate was not affected by the vertical position of the orifice, while it increased as flow velocity increases. This is because when Anguilla japonica perceive a high-speed flow, it swims toward the upstream orifice due to positive rheotaxis.
PROCEEDINGS OF HYDRAULIC ENGINEERING
