Release capacity of Portunus trituberculatus enhancement in coastal waters: A case study in the marine ranching area of Haizhou bay

Abstract

In recent years, the community structure of fishery resources in offshore waters has undergone significant changes, and the resources of traditional commercial fish have gradually declined; as a result, crustaceans have become the main catch. To prevent the loss of resources, it is necessary to carry out ecological stock enhancement and scientifically prevent and control the ecological risks of released species. In this study, based on the Ecopath with Ecosim model, the areas of marine ranching and adjacent waters in Haizhou Bay were used as a case study to construct a temporal dynamic model of Portunus trituberculatus, one of the typical crustacea released in offshore water of China. The ecological carrying capacity (ECC) of P. trituberculatus was assessed, and its impact on other functional groups and ecosystems was predicted. The results showed that the ECC of P. trituberculatus is 42.458 t km−2, and the entire ecosystem would become imbalanced if this value is exceeded. Under the four simulation scenarios, each ecosystem indicator showed positive responses to different degrees, with total system respiration (R) and total system biomass (B) increasing by 244.66% and 236.90%, respectively. We believe that the maturity of the ecosystem in Haizhou Bay is not high, and the marine organisms are mostly in trophic levels Ⅱ to Ⅲ. Therefore, there is still room for the stock enhancement of P. trituberculatus. The model framework provides a method for assessing the ECC of P. trituberculatus in offshore water and offers a scientific reference and practical basis for stock enhancement activities, resource management, and fishing strategies for P. trituberculatus in the offshore waters of China.