Abstract:To understand the responses of hairtail(Trichiurus japonicus)catches to fishing and climate variability in the East China Sea(ECS),the time series of hairtail catches between 1956 and 2006 in the ECS was analyzed,which could be partitioned into inter-annual variation and internal trend.The internal trend was attributed to the monotonic growth of fishing efforts,the result of which was fitted by the Fox model showed that the relation between hairtail catch and fishing efforts was significant(P<0.01).After detrending the catch,variation in the catch was greatly affected by the climate fluctuation,which mainly included land precipitation,monsoon wind speeds,sea surface temperature and a proposed index of tropical cyclones(P<0.05).Variation of those main climatic factors and fishing efforts were significantly correlated with the annual catch(P<0.01).In conclusion,the land runoff brought nutrients to the coastal water,and the monsoons controlled the distribution and availability of the nutrients.In addition,the increase of water temperature was not only positive for the gonad development and maturity of hairtail,but also helpful to the availability of baits for hairtail.Thirdly,the tropical cyclones mobilized nutrient elements and enhanced biological production in many ways such as water mass moving,wind mixing,and upwelling.The paper concluded that both fishing efforts and climate change had influence on the variation of hairtail catch,and the climate changes in the future could be helpful to the increase of hairtail catch in the ECS,but also may result in a much bigger amplitude of catch variation.