Genetic structure of Scomber japonicus (Perciformes: Scombridae) along the coast of China revealed by complete mitochondrial cytochrome b sequences

Abstract

The phylogeography history and contemporary agents of selection for many marine fisheries, characterized by widespread species distributions in the face of significant harvest, remains poorly understood. Chub mackerel (Scomber japonicus) are a widespread species in the Indo-Pacific and represent one of the top five commercially fished species in the world, yet their phylogeographic history remains unknown. We characterized the genetic diversity, structure and demographic history of S. japonicus throughout adjacent Chinese seas (from the Yellow Sea to the South China Sea). Using 220 individuals from 11 sites, we inferred 55 distinct haplotypes from complete mitochondrial cytochrome b gene sequences. Haplotype diversity ranged from 0.505 to 0.967 and nucleotide diversity ranged from 0.00056 to 0.01042. Genetic differentiation (F_st) statistics suggested that the highest level of differentiation existed between the SanYa and SanSha localities (F_st = 0.86977), while the lowest levels of differentiation occurred between the DongGang and ShiDao localities (F_st∼ 0). Kimura’s genetic distances ranged from 0.001 to 0.011 within and from 0.001 to 0.018 between populations. Hierarchical analysis of molecular variance, Neighbor-joining and median-joining network analyses identified significant phylogeographic structure with two localities (SanYa, Hainan of the South China Sea and LianYunGang, Jiangsu of the East China Sea) explaining most of the genetic variation observed, while the remaining populations were poorly differentiated.

Keywords:

• Chub mackerel
• demographic history
• genetic structure
• marine fisheries
• mitochondrial cytochrome b
• Scomber japonicus

Acknowledgements

We would like to thank JC Zheng, H Huang and XY Chen for assistance in sample and data collection.

Declaration of interest

This work was supported by the Special Research Fund for national non-profit institutes (East China Sea Fisheries Research Institute, No. 2008Z02) and the Fund of State Key Laboratory of Genetics Resources and Evolution (GREKF10-01). SMR was supported by an Alberta Innovates Technology Futures New Faculty Award and a Natural Sciences and Engineering Research Council (NSERC No. 735287) Discovery Grant Award. Qiqun Cheng was also supported by the China Scholarship Council (CSC). The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.