River Health Assessment Based On The Fish Integrated Biological Index

In this study,five major rivers in Pingxiang City,Jiangxi Province,were used as the study area,and catches from 16 sampling sites were collected seasonally from June 2019 to May 2020.The structural characteristics and species diversity of fish communities in the region and their response to the environment were analyzed,as well as a preliminary fish biological integrity index evaluation system was constructed and the health status of the rivers was assessed.The main research results are as follows:A total of 20,388 individuals,244.42 kg,were collected in this study and identified as belonging to 4 orders,14 families,46 genera and 56 species,with the Cypriniformes of Cyprinidae being the dominant species(34 species,accounting for 60.71%of the total number of species).Ecotypic analysis showed that the fish composition in the region was dominated by omnivorous,benthic,sticky egg and sedentary fish.Compared to the historical data(1985),the G-F index of fishes was lower and the number of carnivorous,drifting egg,pelagic and migratory fish species and their proportions were lower.Based on the catch data from this survey,the relative importance index analysis revealed that R.ocellatus,C.carpio and C.auratus were the dominant species.The Shannon-wiener diversity index of the fish community ranged from 1.47 to 2.00;the Margalef species richness index ranged from 2.10 to 3.46,the Pielou evenness index ranged from 0.54 to 0.73 and the Simpson dominance index ranged from 0.63 to 0.8.Cluster and NMDS analysis showed that the 16 sampling sites were divided into four groups,of which:group 1 was mainly six sampling sites distributed in the Pingshui,five sampling sites in group 2(except for L2)were mainly distributed in the Ganjiang basin,three sampling sites in group 3 were distributed in the Caoshui,and two sampling sites in group 4 were mainly distributed in the protected area.PERMANOVA analysis showed that the species composition of the fish community differed significantly between the different groups(P=0.002).Pearson’s correlation analysis found that the richness index was negatively correlated with ORP(P<0.01),positively correlated with RW(P<0.01),and positively correlated with WD(P<0.05);the evenness index was positively correlated with pH and Turb(P<0.05);diversity index was positively correlated with pH(P<0.05).Redundancy analysis(RDA)showed the environmental factors affecting the distribution characteristics of the fish community were mainly were WD,pH,and WT.ABC curve analysis showed that the fish communities in Pingshui,Caoshui and Yuanshui were unstable,the fish communities in Lishui were moderately disturbed,and the fish communities in Heshui were undisturbed or minimally disturbed.Based on the fish-based index of biotic integrity(F-IBI),44 candidate indicators were selected,and a total of 13 indicators were selected through distribution range,discriminatory ability and correlation analysis to build the fish biological integrity evaluation index system of Pingxiang Basin.The result that Pingshui,Yuanshui and Caoshui were all"sub-healthy",Lishui was "fair",and Heshui was "healthy" or "sub-healthy"state.