Fish species classification, trophic guilds and geographical distribution of northeast China

Muling River, surrounded by cultivated land of Heilongjiang Province in the northeast of China, experienced sand-digging activities for a long time, and its riverbed has been seriously damaged. However, the knowledge about the impact of this disturbance on the status of fish community structure and diversity was little studied in this river. In this study, environmental factors and fish assembles from Muling River were investigated in spring, summer and autumn of 2015 and 2017, respectively. During the investigation period, 46 species of five orders and 12 families of fish were classified into seven trophic guilds. Our results demonstrated that the fish species diversity indices and variation trends of the Shannon-Wiener diversity index, Pielou evenness index and Margalef richness index were consistent. RDA analysis showed that water depth was significantly correlated with zooplankton feeding habits, and transparency correlated with aquatic plant feeding. This study supports the need for trophic guilds taxonomic studies of freshwater fishes to underpin management in areas subject to significant environmental change.