High-temporal resolution profiles of acoustic backscatter were collected from a traditional bamboo set net along the coast of the Southern Sea, Korea, using sideward-looking multi-beam imaging sonar. These data were used to examine the impact of variations in tidal cycles and current speeds on the bamboo set net. The relatively high influx of fish during the nighttime compared to the low influx and high outflux of fish during the daytime suggests visual avoidance of the net by the fish during the daytime. The observed diel variation in the captured fish flux was significantly correlated with the current speed (day: r = 0.35, p = 0.002, night: r = 0.60, p < 0.001). The ratio of influx and outflux of fish, and current speed were correlated in a linear relationship (day: r = 0.45, p < 0.001; night: r = 0.56, p < 0.001). The fish activity of those inhabiting the bamboo set nets appears to be greatly influenced by day-night differences and current speed. The present study enhances understanding of fish behavior via utilization of a bamboo set net in the coastal zone.
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