Factors influencing tropical Island freshwater fishes: species, status, threats and conservation in Hainan Island

Hainan Island is located within the Indo-Burma global biodiversity hotspot, however, the freshwater fish fauna on this island is poorly understood. Based on field investigations and literature review, we compiled a list of 154 freshwater fish species (0138 native and 16 non-native) belonging to 10 orders, 31 families and 104 genera found on Hainan Island. Of these, 31 species are endemic to China. The native freshwater fish fauna in Hainan Island is affiliated to South China sub-region of the Oriental Region. Current knowledge suggests that overexploitation, water pollution, flow modification, habitat degradation, and non-native species have severely reduced the freshwater fish biodiversity in Hainan Island. To protect freshwater fish biodiversity and fisheries in Hainan Island, some new measures should be adopted and current measures better enforced. This study constitutes an important resource for conservation management of freshwater fishes in Hainan Island.