Fish Composition and Diversity of Four Coral Reefs in the South China Sea Based on Hand-Line Catch

To improve the overall understanding of the fish diversity and spatial patterns of major coral reefs in the South China Sea, fish assemblage composition, dominant species, biodiversity indices, and multivariate analysis of community structure were reported for four major coral reefs based on hand-line survey data in May and September 2018. A total of five orders, 21 families, 45 genera and 121 species of fish were recorded with Perciformes (78.5%) being the most diverse. The highest number (5) of dominant species was found near Chenhang Island while the lowest (2) number was detected at Zhubi Reef. The highest abundance index (7.21) occurred at Zhubi Reef, while the Shannon–Wiener diversity (4.80), Pielou’s evenness (0.81), and Simpson’s dominance (0.95) indexes were all highest at Qiliangyu Island. Based on cluster analysis and non-metric multi-dimensional scaling (NMDS), fish communities varied more spatially than seasonally. Our results led us to hypothesize that the habitat complexity and level of anthropogenic disturbance were the main factors affecting the composition of reef-dwelling fish on each coral reef. Topography was likely responsible for most variation in the spatial pattern of fish diversity.