Behavioral responses of arabesque greenling to trap entrance design

ABSTRACT:   Fish catch efficiency can vary with the design of the trap entrance. To clarify how trap entrance design affects catch efficiency, the responses of fish to different trap entrance designs with different inclination angles or funnel lengths were observed. The passing ratio (i.e. catch) increased and then decreased with increasing inclination angle. An inclination angle of 34° had the highest passing ratio of 43%; the lowest passing ratio was 8% at an angle of 53°. A significant difference in passing ratio was found between two entrance designs ( P  = 0.006). There were significant differences in passing ratio for entrance designs with different funnel lengths ( P  = 0.01). The highest passing ratio was 38% for a funnel length of 29 cm. The approach and passing durations were also compared among the trap entrance designs. The results suggest that modifying the entrance shape can significantly improve the catch efficiency.