Reproductive farming technology in Japanese eel and chub mackerel

Japanese eel(Anguilla japonica)and chub mackerel(Scomber japonicus)are commercially valuable species in Asian aquaculture.The reduction in eel and chub mackerel resources has been a serious problem in recent years that should be addressed by reducing the catch of their natural populations to halt their decline and reach the Sustainable Development Goals.Furthermore,securing sufficient food supply by aquaculture is an important step in addressing the increasing demand for fish products in recent years.Traditionally,juveniles of the Japanese eel and chub mackerel have been captured to be raised in aquaculture.Owing to the extensive research on these species,new technologies have been developed for full-lifecycle aquaculture of Japanese eel in 2011 and chub mackerel in 2014.These technologies are expected to stop the decline of natural resources and provide a stable food supply.Recently,seed production of these species has increased owing to the development of successful broodstock management and larval rearing techniques.Fundamental information on oocyte maturation and ovulation and its application for artificial induction of sexual maturation is needed to produce good quality seeds of the Japanese eel and chub mackerel.Here,hormonal mechanisms and previously and newly developed methods for artificial seed production have been described.