Spatial distribution of the fish community and its relationship with environmental factors in the Bortala River in winter

Abstract:

Knowledge about the differences or variations in the fish community is important to assess and predict the effects of habitat loss or environment degradation on the river ecosystems. The Bortala River is an important interior river in Xinjiang, China. Although research regarding spring and summer fish communities has been reported, that regarding winter fish communities is lacking. Based on fishery resource surveys in November 2016 at the mainstream of the Bortala River, the fish community structure and diversity of the river were analyzed. The results indicated that a total of 1515 fishes were collected at 4 representative sections, which belonged to 3 orders, 4 families, 14 genera, and 15 species. The dominant species (IRI1000) in the mainstream of the Bortala River were Pseudorasbora parva, Abbottina rivularis, and Triplophysa strauchii. A group-averaged hierarchical cluster based on the Bray-Curtis similarity index identified two spatial patterns of the fish assemblage at the 60% similarity level and four patterns of species composition at the 50% similarity level. The canonical correspondence analysis (CCA) suggested that altitude, temperature, and dissolved oxygen were the major environmental factors affecting the spatial patterns of fish assemblages in winter. The results of this study indicated that the species of native fish have declined, and the species of fish with low economic value have increased significantly. The aquatic ecosystem will be destroyed unless effective measures are taken to protect the native fish. Further studies are needed to investigate the mechanisms by which these factors operate together upon the fish assembles in the Bortala River in winter.