| The Jiangjin-Tang River is a tributary of the Yangtze river Reservoir,and the rolling dam in the river was established in the Qing Dynasty.This study was conducted to take samples on fish from six sampling site respectively are Dashibao(DSB),Huilongba(HLB),Xuetangwan(XTW)and Dashazui(DSZ),niujiaotuo(NJT),ShuiPitan(SPT)during March 2018 to July 2018.Employing the morphology as the primary research method auxiliary with DNA barcode technology to perform operations such as fish species identification,phytoplankton species identification,water sample measurement and analysis,and genetic diversity analysis of two fish species.It provides a reference for the protection of fishery resources and the improvement of environmental conditions in Jiangjintang River.And discussed the impact on genetic differentiation of two kinds fish?s breeding habits caused by the ecological isolation of Tanghe Rolling Dam project.Through the study of the Yangtze River tributary,providing a scientific basis and comparison of estimation for the distribution of fish resources in other tributaries,and provides reference for the barrier effect of dam construction on fishery resources as follows: 1.Investigation of fish resources in tang riverThrough collecting catches in six sampling points in Jiangjintang river and employing DNA barcode technology for species identification,the results are as follow: a total collection of 1080 fish samples weighing 48.96 kg,there were 45 species,16 families,37 genera and 5 species were identified.among them,Cypriniformes is the largest proportion,accounting for 68.75% of the total sample,belonging to 10 families,26 species and 31 genera.The dominant species of the river are Cyprinus carPio,Hemiculter leuciscucus and Opsariicjthys bidens.In addition,The Shannon diversity index H ranged from 1.495~2.484,the Margalef species richness index D ranged from 2.935~5.828,the Simpson ecological dominance index C ranged from 0.190~0.258,and the Pielou evenness index J ranged from 0.589 ~0.693.it showes that there is a small range in the dominance index,a small difference in the uniformity of each group and the distribution of fish species at each sampling point is relatively uniform and the difference in the structure of the catch points is not obvious.The fish resources of the Jiangjintang River have been reduced compared with historical data,due to human factors,so there need strengthened protection measures.2.Genetic Diversity of Squalidus argentatus in Tang riverIn order to analyze the genetic diversity of Squalidus argentatus in Jiangjintang river,the relationship between dam establishment and genetic diversity was investigated.Thirty-six silver scorPions at six sampling points in Tang river were used as experimental samples.Analysis of the 696 bp effective sequence of the D-loop control region obtained by using MEGA 6.0 and DnaSP 5.0 software.And a total of 27 mutation sites and 32 haplotypes were detected,and the population genetic diversity index was(Hd=0.923,pi=0.00867),this indicating that the Squalidus argentatus population has rich variation and genetic diversity.The Fst range of above the dam is between 0.09322 and 0.12900.,and The Fst range of the population below the dam is between 0.07595 and 0.12710.The genetic diversity index between the dam above and below the dam is(Fst=0.24831,Nm=0.96),which shows a high degree of genetic differentiation among populations.In addition,from the haplotype distribution,there are 22 haplotypes above the dam and 28 haplotypes below the dam.There are only 4 haplotypes above the dam and 10 haplotypes below the dam.It show that most of the haplotypes above the dam are shared by the sub-dams below the dam,while the haplotypes below the dam are shared above the dam.To a lesser extent.The results showed that the impact of the dam on the genetic structure of the Squalidus argentatus population has already appeared,and the protection of river migratory fish should be strengthened.3.Genetic Diversity of Rhodeus ocellatus in Tang riverRhodeus ocellatus is a kinds of settled fish.There were analyze the impact of dams on settled fish,the sample is analyzed by sampling 187 Rhodeus ocellatus at 6 sampling points in Tang river,A 964 bp D-loop fragment was obtained,and a total of 9 haplotypes were obtained,the sequence differences between individuals were small.The genetic diversity index was(Hd = 0.14542,pi = 0.00346),indicating a low level of genetic diversity.The genetic diversity of the population above the dam and the population under the dam are consistent and are a large group of random exchanges.The change of genetic diversity among the populations due to the dam barrier has not been found,indicating that the dams have such settlements for Rhodeus ocellatus.The genetic diversity of fish is less affected. |
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