Unbaited Light-Emitting Diode Traps Performance for Catching Orange Mud Crabs

Abstract

Mud crabs (Scylla spp.) are a vital fishery resource and targeted for a valuable source of income for coastal communities throughout the Indo-Pacific region. Baited traps are a considerable expense in crustacean fishing. Hence, the present study was performed to investigate the catchability of Scylla olivacea in response to light-emitting diodes (LEDs) in captivity and field conditions. We used a new experimental setup in the captivity condition that revealed most S. olivacea were attracted to green, blue, and white LED lights and no attractive effect by red LED lights similar to the controls. Field studies have shown that the catch per unit of effort (CPUE) of S. olivacea and other organisms, including bycatch species, is significantly higher when conventional mackerel and chicken head baits are used. However, unbaited traps equipped with green LED lights produced low CPUE of S. olivacea. Moreover, baited trap with chicken head, mackerel and green LED caught 4.52%, 7.28% and 2.18% more CPUE of S. olivacea compare to empty trap, respectively. Besides, both the mackerel and chicken head treatments resulted in the higher average CPUE of S. olivacea than did the green LED treatments; 0.66, 0.38 and 0.13 per trap. No significant differences were detected in the average carapace width of S. olivacea across all treatments. Our findings demonstrated that mud crabs can be captured using artificial lights, like other aquatic species but further in-depth studies and specific modifications to improve the performance of LED lights are warranted.