Simulation of oyster ecological carrying capacity in Sanggou Bay in the ecosystem context

Aquaculture is a rapidly increasing industry, and managers in China are searching sustainable development in the context of much more intensive culture. Our study area focused on an embayment that exposed to suspended culture of oysters. Impact of oyster expansion was evaluated in the context of ecosystem which do not limits to the phytoplankton-oyster relationship but other interspecific relations by the use of food web model. Following recently proposed measures, the ecological carrying capacity (ECC) was defined as the maximum amount of oyster biomass that would not yet cause ecosystem function to depredate beyond their resilience capacity, i.e., not to cause any other group's biomass to fall below 10% of its original biomass. The result suggests that an increase of oyster biomass caused negative impact on the ecosystem in terms of biomass of the most of functional groups and ecosystem indicators such as flow diversity and transfer efficiency. The ECC of oyster in suspended culture was 976 t km(-2)(1.8 times of present biomass), and exceeding the levels will cause zooplanktivorous fish biomasses to fall below the 10% threshold. The ecosystem-based ECC assessment method in the present simulation dynamically predicted the impact of oyster development on other organisms in the environment to guide the sustainable development of bivalve culture in Sanggou Bay and provides an approach for the assessment of bivalve ECC in other parts of the world.