Swimming capability of target fish from eight hydropower stations in China relative to fishway design

Abstract

The four major Chinese carp (MC), Schizothorax fish species (SF), and Cobitidae fish species (CF) are the most important target fish species in China. The swimming behaviour study of three target fish groups is the key to Chinese fishway designs. The 20 min critical swimming speed (Ucrit-20 min) and endurance of the target fish species in relation to body length, swimming speed, and water temperature were estimated using multiple linear regression. The results indicated that both fish body length and water temperature had a significant effect on swimming capability. Performance comparisons indicated that SF were remarkably strong swimmer. CF possess slightly greater swimming capability than MC. The entrance velocity of the upstream fishway should be greater than Ucrit-20 min, but less than maximum swimming speed to make the flow out of the fishway noticeable. The maximum swimming distance could be estimated using endurance model at flow velocity of 1.2 m·s–1. For the downstream-migrating juvenile fish, it was suggested that the flow velocity of turbine intake should be less than maximum sustained speed avoiding entering turbine.