Determining a More Environmental than Spatial Influence on Structuring Fish Communities and Ecological Boundaries of Fangcheng Coastal Waters, Northern South China Sea

Fangcheng coastal waters in the northern South China Sea provide critical habitats for many commercially important fish species by offering essential spawning, feeding, and nursery areas for one or more stages of their life history. A total of 127 fish species and environmental data were collected by trawl surveys at 18 sites of Fangcheng coastal waters in Spring and Fall of 2014. The species richness and abundance of fish community were analyzed, and multivariate statistical approaches were used to quantify the relative effects of environmental and spatial factors on structuring fish community and characterizing ecological boundaries of Fangcheng coastal waters. Results showed that the fish community of Fangcheng coastal waters had high species richness rather than being dominated by just one or a few species, and suggested the higher importance of environmental than spatial factors in structuring the fish community. Water temperature was important in predicting the fish community patterns in both seasons. The most important factors influencing fish compositions during the spring and fall were pH and dissolved oxygen (DO) respectively. This study provided a multivariate statistical framework for identifying the roles of environmental and spatial factors in structuring fish community and determining fishery management units and their regulating factors.