Spatial avoidance of tu-fish Schizopygopsis younghusbandi for different sounds may inform behavioural deterrence strategies

Abstract

Water diversions for hydropower and other applications can potentially affect wild fish populations. Although some evidence indicates that acoustic barriers can prevent fish from entrainment into such infrastructures, few studies have been conducted on filtering candidate sound stimuli. Here, the effectiveness of three types of sounds acting as acoustic barriers to prohibit the movement of tu-fish Schizopygopsis younghusbandi (Regan) was evaluated. The phonotaxic response of the fish to recordings of hissing sound (sound of Chinese alligator Alligator sinensis hissing), outboard motorboat and pile driving noise, compared to control conditions (recordings of ambient riverine noise), was investigated using playback approaches in a fibreglass tank. The tu-fish reacted to the hissing sound at relatively low sound intensity by exhibiting negative phonotaxis with significantly more responses (F3,79 = 49.590, p < 0.01) and faster swimming (F3,219 = 310.086, p < 0.01) away from the sound source during the 10-min trials than to control conditions. However, the fish were relatively impervious to the outboard motorboat and pile driving noise even when the sound intensities were increased. These results indicate that the potential use of the hissing sound to manipulate fish behaviour and to help protect them from water diversion structures.