Cobia, Rachycentron canadium, is one of the most potential sea-cagefarmed fish species in Taiwan. Recently, the disease resistance andsurvival rate of cobia fingerlings are lower than before, resulting in reduced development of farming industry. The possible reason is probably due to the inbreeding depression that cause cobia early-maturing and growing up slowly. We want to solve this problem by using selected breeding method to improve the growth performance and disease resistance of cobia fingerlings. The purpose of this study is aimed to compare the growth performance and disease resistance between the progeny of wildcatched cross artificial reared broodstock and in-bred artificial reared broodstock and proceed the selective breeding to improve the quality of the seed. Finally, we will proceed analysis of cobia phylogenetic relationship and fingerlings sea-cage culture test to confirm the possibility and effects of cobia selective breeding.