Abstract:The ecological fitness of hatched and released juveniles, during their early post-release period in Xiangshan Bay, was investigated through analyzing their post-release growth performance and feeding over a 3-month period. During the early days following the release, the fish exhibited poor feeding and growth performances. After the first month following the release, approximately 80.95% of the individuals were detected to have empty stomachs. In addition, the dietary niche breadth index was only 63% of that of their wild conspecifics. The hepatopancreas somatic index reduced compared to that prior to release, indicating that the utilization of the energy stored in the liver should be an important route for the juveniles to cope with starvation induced by a low-feeding success. During this period, the growth in length tended to stagnate, with a specific growth rate of only 0.079%/d. Approximately 2 months after release, the empty stomach percentage decreased to 46.15% and the index of dietary niche breadth increased to 2.16 for the released fish. Meanwhile for wild fish, the empty stomach percentage was 38.24% and the index of dietary niche breadth was 2.62. The gaps of the empty stomach percentage and the index of dietary niche breadth between wild fish and released fish were greatly shrinking. Thus, it strongly suggested that the released fish were successfully adapting to the natural feeding conditions. As the feeding ability improved, the hepatopancreas somatic index of the juveniles gradually returned to the level prior to release. Meanwhile, the specific growth rate of the released fish increased sharply. The released fish underwent a period of compensatory growth, a phase of rapid growth following starvation, which gradually returned to the normal growth pattern.