Research
| Title： | Population Structure of Wild Schizothorax kozlovi in the Upper Yangtze River Based on mtDNA and Stable Isotopes, and Their Relationship with Ambient Temperature |
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| First author： | He, Yongfeng; Gong, Jinling; Wu, Xingbing; Zhu, Yongjiu; Yang, Deguo |
| Journal： | FISHES |
| Years： | 2022 |
| DOI： | 10.3390/fishes7050292 |
| Abstract： | Schizothorax kozlovi, as an endemic and vulnerable fish of the upper Yangtze River in China, faces many threats. In order to expose the population structure of wild S. kozlovi, the carbon and oxygen isotopic ratios in the otoliths, and the gene sequences of two common mitochondrial markers (Cytb and COI) were investigated in four sampling locations, and then their relationship with ambient temperature was further investigated. In general, it exhibits limited geographic population structuring of S. kozlovi in the upper Yangtze River by both mtDNA and stable isotopes. The values of otolith stable isotope ratios varied from -15.30 parts per thousand to -12.37 parts per thousand for delta O-18 and from -10.10 parts per thousand to -6.13 parts per thousand for delta C-13. Significant relationships were revealed between stable isotope ratios and specific mean monthly water temperature variables (from November to March), indicating low temperature effect on otolith stable isotope ratios. Haplotype diversity and nucleotide diversity were 0.928 and 0.00778, both exhibiting high levels. A median-joining haplotype network indicated a mixture of geographical distribution but exhibited two distinct haplotype lineages (Clade I and Clade II). AMOVA detected that the higher percentage of genetic variance was within sampling locations (96.94%) and between two haplotype lineages (72.82%). Most F-ST values between sampling locations showed small levels of genetic differentiation except the differentiation between population SJ (Sanjiangkou) and JP (Jinping). Therefore, two haplotype lineages and population JP of S. kozlovi in the upper Yangtze River are suggested as three management units for conservation due to their moderate-to-great genetic differentiation and isolated habitat. |
