Effects of the trap entrance designs on the catch efficiency of swimming crab Charybdis feriata fishery

Abstract The swimming crab Charybdis feriata fishery is important to the coastal fishing communities of Vietnam, particularly in the province of Quang Nam. Trapping is considered a low impact and fuel-efficient fisheries capture technique that is drawing increasing attention as concerns regarding the impact of fisheries on ecosystems and the environment grow. However, traps typically have low capture efficiency for most crab species and there is considerable interest to improve catchability. In this study we investigated the impact of modifying the number of trap entrances on a traditional trap design, and also the colour of entrance-netting, on the catch rate of swimming crab in the Vietnam trap fishery. In the first experiment we compared catch rates between a traditional three-entrance trap and a modified one-entrance trap design, and found that the modified one-entrance trap had a 24 % higher catch rate. In second experiment, we compared catch rates of one-entrance traps having green or yellow entrance-netting and found that yellow netting increased catch rates by 31 %. This study shows that fishing enterprises could improve their swimming crab trap fishery by using modified one-entrance traps with yellow entrance netting.