Study On Fish Diversity In Lanzhou Reach Of The Yellow River Based On Environmental DNA Technology

Human activities have had unprecedented impacts on biodiversity and ecosystem stability.Biodiversity monitoring is the basis for formulating conservation and management strategies scientifically.Although the traditional survey methods play a significant role in biodiversity surveys,they have many disadvantages such as unfriendly to environment,limited accuracy of survey results,relying on expert experience for species identification,and difficult to detect rare species.Environmental DNA(e DNA)technology is an aquatic biodiversity surveying method based on the molecular biology and can effectively overcome the above-mentioned disadvantages.Little is known on fish diversity in Lanzhou reach of the Yellow River.In this paper,e DNA technology was used to survey the fish diversity in the spring and summer in Lanzhou reach of the Yellow River.The research mainly consists of two parts: 1)Explore the feasibility of using environmental DNA technology to detect fish diversity in the Lanzhou section of the Yellow River and the the suitability of environmental DNA primers in the laboratory.2)The technology was used to survey fish diversity in the spring and summer in Lanzhou reach of the Yellow River.The results of this research could be concluded as follows: 1.Explore the feasibility of using environmental DNA technology to detect fish diversity in the Lanzhou section of the Yellow RiverThe e DNA of fish can be extracted from Lanzhou reach of the Yellow River,The concentration of e DNA is related to biomass and has a positive correlation within a certain period of time.The concentration of e DNA gradually increased when the fish entered the water;after a period of time,the concentration did not incresae any more and it maintained dynamic equilibrium;when the fishes were removed from the water,the e DNA concentration gradually decreased.This experiment shows that e DNA can exist in the fish tank at Fuding base for about 15 days.2.Screen and verify universal primers for fish environmental DNA in the Yellow River Lanzhou ReachThe universal primers for fish were screened.The results showed that the universal primer Mi Fish had higher efficiency and better sensitivity for DNA amplification of fish tissues from Lanzhou reach of Yellow River.It was also good for the e DNA amplification of Yellow River water samples by this primer.And 13 species of native fish were successfully identified in Lanzhou reach of Yellow River,after the PCR products of e DNA was subjected to high-throughput sequencing and data analysis.It showed that Mi Fish can be used as a universal primer for surveying fish diversity in Lanzhou reach of the Yellow River by e DNA technology.3.Investigate fish diversity in spring and summer of Lanzhou section of the Yellow River based on environmental DNA technologyThe e DNA technology was used to survey fish diversity in the spring and summer in Lanzhou reach of the Yellow River.And traditional cage fishing were also used at some sites to compare the efficiency of the two survey methods.The results are as follows:(1)Spring.1.kinds of fish: The high-quality sequences of 11 sites were between 95,141 to 278,230 sequenced by e DNA technology.After comparison and annotation of data,a total of 28 species of fish were indentified by e DNA technology,which categorized into 1 class,8 orders,17 families and 27 genera.A total of 6 species of fish were caught by ground cages,which categorized into 1 order,3 families and 5 genera.There were few common fishes by the two survey methods.Only 2 and 1 common fishes were caught in Shuichuan(SCD)and Yongjing(YJD),respectively.2.Resources: The fish resources at each site showed that the relative abundance of Operational Taxonomic Unit(OTU)of Triplophysa was very high in Damiao(DMD),Yingping(YPD)and Wufo(WFD),and the relative abundance of OTU of Oncorhynchus was as high as 89% in Liujiaxia(LJXD).The catches were the most abundant in SCD.3.Fish diversity: The results of fish diversity in 11 sites show that the potential non-native fish data affect the richness of the fish diversity.Whether these data were excluded or not,the ? diversity index all showed that the fish diversity was higher in YJD,Wuliu(WLD)and Dongwan(DWD)and lower in DMD and LJXD.The ? diversity showed that the potential non-native fish data had a significant impact on the Jaccard distance,but had a smaller impact on the Bray-Curtis distance.In general,it was small for the differences in fish communities in Lanzhou reach of the Yellow River in the spring.(2)Summer.1.kinds of fish: The high-quality sequences of 11 sites were between 194,585 to 271,970 sequenced by e DNA technology.After comparison and annotation of data,a total of 95 fish species were indentified by e DNA technology,which categorized into 1 class,21 orders,23 families and 82 genera.A total of 11 species of fish were caught by ground cages,which categorized into 3 orders,5 families and 10 genera.Although the number of common fish species were few by the two survey methods,most of sites had common fish species.2.Resources: The fish resources at each site showed that there were Oncorhynchus,Schizothorax,Cyprinus,Schizothorax,Triplophysa and Sinibotia at each site,and their relative abundance of OTU were higher.The catches data showed that there were 5 genera at each site,but the resources were different.3.Fish diversity:The fish diversity of 11 sites was assessed.Whether potential non-native fish data were excluded or not,the ? diversity index all showed that the fish diversity was higher in WFD and DWD and lower in LJXD and SCD.The results of ? diversity indicated that there were great differences in the species composition and abundance between Yongjing-Damiao(JYD-DMD),and the fish communities were small differences in Lanzhou reach of the Yellow River in the summer.4.The complete mitochondrial genome sequence and phylogenetic position of Gobio coriparoidesG.coriparoides is very sensitive to circumstance around its habitat and accordingly become an environmental indicator,which has important significance for the protection of the environment and biodiversity.The complete mitochondrial genome sequence of G.coriparoides was obtained using primer-walking method,which provided effective data for further research on the genetic structure,molecular evolution and phylogeny of the G.coriparoides and related species.At the same time,The information is supplemented to the NCBI database.