To study migratory routes of the largehead hairtail,Trichiurus lepturus,in the East China Sea(ECS),the Yellow Sea(YS)and the Bohai Sea(BS),the fishing records were analyzed with the data collected in the years 1971,1972,1981 and 1982.Firstly,moving images of largehead hairtail were plotced.Based on the images,migratory routes of the fish were further studied in the area.The results showed that wintering ground,spawning ground and feeding ground of the fish were wide and overlapped in space with each other.Furthermore,these migrations of the fish were overlapped in month,then showed its characteristics of batch migration.Overlapping in ground spaces and migrating of batch were two important and ecological characteristics for largehead hairtail.The wintering grounds of north population of the fish was located at 32°00'-36°00'N,124°00'-126°00'E,in the waters of yellow sea warm current.In March-July of each year,the largehead hairtail groups entered Haizhou Bay,Rushan Bay,Sea Island and bays in Bohai,the places were spawning ground and feeding ground for the fish.In Septamber-November,the fish groups moved out of Bohai,passed the Chengshan Cape,collected the fish groups from Haizhou Bay,Rushan Bay,Sea Island along waters of the forbidden fishing zone line,on the way to go to its wintering ground.When the groups arrived at 34°00'N,the batch groups turned to the southeast,to the wintering ground lies in the south-east of the Yellow Sea.The wintering grounds of the south population were mainly located in the waters near the forbidden fishing zoneline in the mid-southern East China Sea,followed by the waters in west of Jeju Island.From March-April,the fish groups moved north-east towards west waters of the Zhoushan Fishing Ground and the Changjiang Estuary Fishing Ground roughly at the speed of one degree of latitude for every two months until May-July.The fish finished spawning migration by reaching the Zhoushan Fishing Ground and the Changjiang Estuary Fishing Ground which were their spawning grounds.During July-August,after spawning,feeding groups migrated north to Dasha Fishing Ground at the south of YS for feeding and growing.In September,the groups arrived near the forbidden fishing zoneline at 35°00'N,the northern feeding ground of south population.Under influence of cold northwest monsoon after October,the population returned to the Changjiang Estuary.From there,the fish split into two groups,the major one migrated southward back to wintering ground in nearshore waters in the mid-southern East China Sea,and the small group moved back to the wintering ground in offshore waters.The main water masses affecting wintering migratory route of the fish are the Taiwan Warm Current and the Yellow Sea Warm Current.