Evaluating Ecosystem Characteristics and Ecological Carrying Capacity for Marine Fauna Stock Enhancement within a Marine Ranching System

China has recently launched extensive marine ranching projects, highlighting the need for scien-tific evaluation of ecosystem structure and function to guide their development. This study estab-lished two energy flow models and an evaluation index system to assess the structure, function, carrying capacity, and ecological status of both a marine ranching ecosystem and a nearby control site in the Beibu Gulf. The results showed that the ranching ecosystem outperformed the control ecosystem in terms of food chain length, system size, and the ecological carrying capacity of eco-nomically important species. The ranching ecosystem was classified as "relatively good," while the control ecosystem was deemed "relatively poor," confirming the success of the ranching efforts. Mussels, large crabs, and Scorpaenidae were identified as key species for stock enhancement based on their biomass potential. Scenario simulations using Ecosim, driven by biomass and fishing factors, indicated that stock enhancement strategies targeting MOB (mussels, oysters, and barna-cles) significantly improved the ranching ecosystem, raising its status to "good." However, the simulations also revealed that stock enhancement had limited effects on optimizing food web structure, system organization, and energy transfer efficiency, suggesting that a combination of strategies is necessary for further improvement.