Research progress on life history and resource conservation of anadromous Coilia nasus in the Yangtze River
Coilia nasus is widely distributed in the Yellow Sea,Bohai Sea,East China Sea and Yangtze River,especially in the Yangtze River Basin.In recent years,due to environmental degradation,selective overfishing and construction of coastal water conservancy projects,the resources of C.nasus in the Yangtze River have declined seriously.In this regard,China has launched a series of national policies to restore,the resources of C.nasus.Based on this background,this paper systematically sorted out the life history,resource status and the causes of resource decline of C.nasus,put forward the countermeasures of resource conservation,and looked forward to the future development trend.The life history of C.nasus was divided into five stages:hatching stage,larval stage,juvenile stage,sub-adult stage and adult stage.The growth,feeding and habitat environment of each stage were different.Among them,the average growth rate of early individuals was 0.73 mm per day.The growth rate of adult fish varied greatly,the maximum body length of 1-year-old fish was 228 mm,while the maximum body length of 4-year-old fish was 410 mm.In the early stage,the type of food consumed was a continuous process of change,from egg yolk,microorganisms,small cladocerans,cyclops,to water fleas and large cladocerans.Adult fish will eat mysid shrimps,krill,polychaetes,shrimps and fish.In the early stage,it inhabited in the freshwater environment,and in the adult stage,it migrated to the estuary and adjacent waters.The Ten-year Fishing Ban of the Yangtze River had a positive impact on the resources of C.nasus,promoted the recovery of resources,and highlighted the importance of the Yangtze River fishing ban on the recovery of C.nasus resources.At the same time,the main reasons for the decline of C.nasus resources were as follows:the change of hydrological conditions,the pollution of water environment,the overfishing and the destruction of important habitats.The main recommendations include:1)Strengthening monitoring of key waters,strengthening resource enhancement and release,improving important habitats,and continuously strengthening fishery supervision;2)The breeding habitat suitability index model shall be established to analyze the potential impact of habitat environment on the complementary population of C.nasus;3)The habitat suitability index model of C.nasus cluster shall be established,and the fishery rapid reporting system of C.nasus fishing ground shall be developed.
万方数据
维普
