The positive effects of typhoons on the fish CPUE in the South China Sea

Due to the logistical difficulties associated with fish data sampling after typhoons, short-term effects of typhoons on fishery in the South China Sea (SCS) have not been well-understood. The present study is to evaluate the impacts on the fish catch per unit effort (CPUE) owing to the three typhoons Chanthu, Vicente, and Kai-tak in the northwestern SCS, using long-term fish catch data and satellite data. The results show that the CPUE of total catch and some sorted catches have been changing because of the typhoons. On total catch, firstly, the CPUE has increased approximately 0.32 kg h−1 kw−1, 0.20 kg h−1 kw−1, and 0.25 kg h−1 kw−1 during the three typhoon periods. Then, the CPUEs decreased to the pre-typhoon level in about three weeks. Thirdly, among the three typhoons, the slow-moving Chanthu has caused a larger increase in CPUE. The typhoons impact was two-pronged, depending on fish species. One is the positive effects on meso-demersal fishes, cephalopoda and pelagic fishes. The other is the increase in CPUE of low trophic level carnivorous fishes after the three typhoons. This research provided the first evidence of CPUE increase after typhoons in the open sea.