Pearl River is one of the produce and export area for aquacultural products, and the rapid development of aquaculture is also one of the main results for the past shrinkage of mangrove ecosystem and the difficult restoration of it. Thus, the ecological economic benefit and impact of these aquaculture systems have great effect on regional sustainable development.

Based on an integrated study of emergy, economic analysis and sensitivity analysis on three fish aquaculture systems at wetlands surrounding the Pearl River Estuary in South China, Drs. LI Linjun, LU Hongfang, and REN Hai found that the three systems studied had similar emergy characteristics, despite their very different economic characteristics. Counter intuitively, the high economic input and output mode did not have higher environmental impact or lower sustainability compared with low economic input and output mode. Apparently, the sustainability of an intensive aquaculture system is determined mainly by the quantity of natural renewable resources exploited. The large differences in economic benefits and environmental impacts between the mangrove reserve and the aquaculture systems demonstrated the important role of nature reserves on preserving the sustainability of an estuary. Transformity (TR) and Emergy Yield Ratio (EYR) are both indicators of system efficiency, but from different points of view, and they produced opposite results in assessing the efficiency of the same system in this study. The ratio of EYR to TR might be used in addition to the EYR and transformity as a discreet perspective on overall system production efficiency.

The relative research results have been published on the international journal, Ecological Indicators (2010.11:526-534).