Genetic diversity and population structure of Hemibagrus guttatus (Bagridae, Siluriformes) in the larger subtropical Pearl River based on COI and Cyt b genes analysis

Abstract

Understanding the genetic diversity and population structure of fish species is crucial for the sustainable use and protection of fish germplasm resources. Hemibagrus guttatus (Bagridae, Siluriformes) is widely distributed in the large subtropical Pearl River (China) and is commercially important. It's population have been declining. The genetic diversity of wild H. guttatus is not clear, despite its important ecological significance. In this paper, genes mitochondrial cytochrome c oxidase subunit I (COI) and cytochrome b (Cyt b) were used to analyze the genetic structure of H. guttatus population collected from six geographical populations in the main streams of the Pearl River. The results showed that the nucleotide diversity (π) and haplotype diversity (Hd) of wild H. guttatus was low (π < 0.005; Hd < 0.5). In addition, H. guttatus haplotypes did not cluster into clades according to geographical distribution, as revealed by neighbor-joining tree analysis. Analysis of molecular variance analysis (AMOVA) and F-statistics (Fst) values showed high homogeneity among wild H. guttatus populations. Our results suggest that there is degradation in germplasm resources of H. guttatus that could destabilize the sustainable use of this species and there was an urgent need for conservation of this species in South China.