Abstract: Marine ranching is an important component of carbon sink fisheries. In order to assess the biological carbon storage of fishery resources in different functional areas of marine ranching, based on the trawl survey data from the Zhuhai Wailingding marine ranching in spring, we analyzed the current status of fishery resources, measured the biological carbon content of fishery resources, and estimated the biological carbon storage of fishery resources in the marine ranching. The results show that the biomass of fishery resources in spring was 4 505.48 kg; the resource density was 458.34 kg·km⁻², which was 23.34% higher than that in the contrast area; the carbon content of wet biological samples in fishery resources was 6.53%−17.02% for Osteichthya, 8.55%−10.19% for Chondroichthya, 6.70%−11.84% for Crustacea, 6.48%−9.89% for Cephalopoda, and 27.04%−27.39% for Bivalva; the biological carbon storage of fishery resources of the marine ranching was 495.63 kg; the carbon density was 50.42 kg·km⁻², which was 46.40% higher than that in the contrast area; the carbon density followed a descending trend of stock enhancement area>new artificial reef area>original artificial reef area>contrast area. It is preliminarily suggest that according to the differences in biological carbon content among different fishery resources, the carbon storage capacity of marine ranching could be improved by adjusting the structure of fishery resources through artificial reefs, stock enhancement and other means.