Japanese eel is an economically important aquaculture species in East Asia. Because the commercial scale of artificial propagation of the glass eel has not been established yet, the needed elvers were all caught from the wild. The shortage in the supply of the elver has became more and more serious in recent years. This results is a serious bottleneck for the aquaculture development. Japanese eel is a catadromous fish, most glass eels migrate to upstream and grow in freshwater until maturation. The release of eel into natural environment is considered as the feasible method to enhance elver recruitment. Therefore, the restocking activity has been launched by Taiwan Fisheries Research Institute since 1976 and a total of 127,498 eels (46,100 kg) had been released during the past 66 events. In addition, the evaluation on the efficiency of restocking activity would also be carried out.