Lots of yellowfin tuna juveniles are caught around the artificial floating reefs that arelocated at south-western coast of Hsiao Liu Chio island. However, the price of juveniletuna is low due to its smaller size. The aims of this project are to improve the fishingmethod, handling and transportation techniques and to achieve the sucess of cageculture and artificial propagation of tuna. White nets will be used to hold the newlycaughtjuveniles to improve the survival rate of wild tuna juveniles. Growthperformance, condition factor, oil content of muscle, blood parameter and diseaseresistance of yellowfin tuna reared in offshore cages will be studied. Some yellowfin tunawill be transferred to cement ponds to study their growth performance, feed conversionrate, water quality requirements and disease resistance in pond environment.