Abstract: The construction of water supply facility is one of the effective ways to improve the fishway efficiency. How different forms of water supply change the swimming strategy of fish and attract them to enter the fishway entrance is a hot topic. In this study, the migration behavior of Schizothorax prenanti was examined under three water supply conditions with different distances and discharges by designing a generalized model of a fishway entrance. The results showed that compared with the condition without water supply, fish passage rate was significantly improved (P<0.05) under the water supply by bypass channel with a horizontal distance of 1 m to the fishway entrance and another bypass channel in which the water flowed down from top with a horizontal distance of 0.65 m to the fishway entrance. By extracting the corresponding velocity field and turbulence field on the path of the successfully traced fish, the preferred flow velocity area of Schizothorax prenantiwas from 0.6 to 0.8 m·s^-1 and they would escape from the high turbulence (greater than 0.04 m²·s^-2). The low turbulence area (0.01 m²·s^-2) was preferentially selected by fish for going upstream. This study verifies that the turbulent kinetic energy and velocity are important hydraulic factors affecting fish migration and provides reference for design and optimization of fishway entrance supply water.

Key words: simulated acid rain, chlorophyll fluorescence, photosynthesis, Quercus glauca.