Co-culture of multiple aquatic species enhances vegetable production in coastal Shanghai

Abstract Global societies witnessed rapid increase in population and accelerating demand for vegetables from cities along the coastal areas (e.g., Shanghai). Development of “multiculture”, “polyculture”, or “co-culture” systems along the coastal areas in Southeast Asia in turn become a preferred choice for installing future aquaculture. To build much needed knowledge guiding the design, ecological benefits, and performances of these newly explored vegetable-aquaculture systems, we designed a nested block experiment and conducted a 3-year study of cauliflower-aquaculture farming on the island. We found that farming type significantly affected the arthropod herbivores and predators, including herbivore abundance and the abundance, species richness and Shannon's diversity of the predators. More importantly, farming type had a significant effect on insecticide use, cauliflower yield and economic returns. The reduction in insecticide use promoted predator diversity and cauliflower yield in co-cultured cauliflower aquaculture as indicated by a significantly negative relationship between amount of commercial insecticides and arthropod predator diversity, as well as between amount of commercial insecticide and cauliflower yield. We conclude that co-culture practice in cauliflower-aquaculture enhanced agricultural production while decreasing use of insecticide and herbivore abundance, and increasing the abundance and diversity of predators, vegetable yield and economic value.