Analyses on fishing ground and catch composition of large-scale light falling-net fisheries in South China Sea

Based on the monitoring data of QIONG WEN CHANG NO.3180 from August 2005 to May 2010, we analyzed the fishing grounds, fishing season and dominant species of large-scale light falling-net fisheries in South China Sea. Results show that the dominant species are Sthenoteuthis oualaniensis, Carangidae, Trichiurus japonicus, Loligo and Auxis, which account for 40.94%, 21.92%, 13.56%, 10.17% and 6.21% of the total, respectively. We divide the fishing grounds into three areas: area Ⅰ, which is located in deep waters close to Xisha Zhongsha Islands; area Ⅱ, located in continental shelf waters outside Pearl River estuary; and area Ⅲ, located in continental shelf waters in Beibu Gulf. Dominant species of area Ⅰ is S.oualaniensi, which account for 91.10% of total landings, and the second most species is large tunas (Thunnus albacares, T.obesus), making up 0.83%. Dominant species of area IIⅡare Carangidae, Loligo and T.japonicus, which account for 42.88%, 20.34% and 14.52%, respectively. Dominant species of area Ⅲ are T.japonicus, Carangidae and Loligo, which account for 45.06%, 22.16% and 14.58%, respectively. The fishing vessels operate mainly in area Ⅰ from March to May, in area Ⅱ from August to September and December to February, and in area Ⅲ from October to November. Besides, annual fishing days in area Ⅰ vary dramatically. It is suggested that Fishing Closed Season for falling-net fishing in area Ⅰ should be adjusted.