Fish Biodiversity In The Bulhatong River Basin Research On The Characteristics Of Community Structure

The Burhatong River is the main branch of the middle stream of the Tumen River,it’s 242 km long,and 7141 km~2 of drainage area,rich in water and fish resources.However,as interferences of human activities increase,the distribution area,number and species of fishes decrease rapidly,therefore,it is urgently needed to launch an investigation on fish resources of the Burhatong River.In this research,we went to the Burhatong River basin,investigated on the fish community structure by analyzing species and functional group,assessed river ecosystem health by analyzing environmental factors which influenced fish community.We hope to provide scientific data and basis to protect water and fish resources of the Burhatong River.The main research findings are as follows:(1)In July 2022,a total of 28 species of fish were collected in the Bulhatong River Basin,divided into 7 orders,10 families,and 23 genera,totaling 6085 fish.The Cypriniformes has the highest number of species,with a total of 18 species.The Mulliformes has 5 species,while the Sevengilliformes,Jaundiformes,Stingfish,Siluriformes,and Perciformes have only 1 species.The density of carp shaped fish is the highest,accounting for 98.04%.The density of other order fish is 0.79% in the order Mulliformes,0.51% in the order Siluriformes,0.33% in the order Lampetiformes,0.30% in the order Perciformes,0.02% in the order Perciformes,and 0.02% in the order Perciformes.There are two dominant species,namely Phoxinus lagowskii and Nemachilus nudus.The average number of fish species at each sampling point in the Bulhatong River Basin in this survey is 4.15 ± 0.18,the average fish density is 59.11 ± 3.33 g,and the average fish biomass is 304.03 ± 19.95.The average Shannon Weiner index is 2.78 ± 0.06,the average evenness index is 1.31 ± 0.02,and the average richness index is 0.61 ± 0.10.(2)4 functional groups were divided according to nutritional structure,in which the omnivorous group took the highest percentage in both number of species and density,while the phytophagous group was the lowest in number of species,and the carnivore group was the lowest in density.3 groups were divided by environment tolerance,the medium pollution tolerant group took the highest percentage in density,the pollution tolerant group took the highest in number of species,while the pollution sensitive group was the lowest in both indices.3 groups were divided by spawning type,viscous egg group was the highest in number of species,nesting group was the highest in density,while the floating group was the lowest in both indices.3 groups were divided by habit water zone,demersal group and middle and lower group were the same in number of species,mesopelagic group was the highest in density,while pelagic group was lowest in both indices.(3)Pearson analysis results showed significant differences between water environmental factors of the Burhatong River.PCA analysis showed that the 5 main factors influencing water environment were conductivity,water temperature,total nitrogen,ammonia nitrogen,and TSS(total suspended solids).DCA analysis on fish community and functional groups showed that TSS and water temperature were important on structure of fish community.TSS mainly influenced on the middle and lower group and the carnivore group;water temperature on the middle and upper group,the demersal group,and the carnivore group;conductivity on the pollution tolerant group;ammonia nitrogen on the medium pollution tolerant group;total nitrogen on the phytophagous group and the pollution sensitive group.The viscous egg group was influenced by water temperature,total nitrogen,ammonia nitrogen,and TSS.(4)Water environment was assessed by comprehensive pollution index,only 1 site was qualified,taking a percentage of 0.95%,4 sites were basically qualified(3.81%),55 sites were slightly polluted(52.38%),45 sites were highly polluted(42.86%).Results above indicated that the Burhatong River area was slightly polluted.Water ecosystem was assessed by F-IBI(fish-index of biotic integrity),22 sites were excellent(22.92%),15 sites were good(15.62%),28 sites were average(29.17%),and 31 sites were bad(32.29%).Results above indicated that the ecosystem of the Burhatong River was average.