The impact of Yangtze River discharge on the genetic structure of a population of the rock bream, Oplegnathus fasciatus

ABSTRACT

As a rocky reef species, Oplegnathus fasciatus displays significant geographic differences that may be congruent with patterns of molecular variation. We used 10 polymorphism microsatellite loci to characterize the genetic structure and test the impact of ocean currents and the Yangtze River on the population genetic connectivity of the rock bream, O. fasciatus, sampled from Jiaonan (JN), Zhoushan (ZS) and Taiwan (TW). The average number of alleles was 17.78, with a total of 160 alleles, and the average allele value in the East China Sea (ZS = 13.70) was higher than that in the Yellow Sea (JN = 6.70). The individuals at the ZS location showed the highest expected heterozygosity (He = 0.86), Nei's genetic diversity (H = 0.84) and Shannon genetic diversity (I = 2.21). Genetic bottleneck tests showed that individuals had experienced a recent bottleneck effect in the JN location. AMOVA analysis showed that 12.19% of genetic variation existed among populations, indicating significant population genetic differentiation in the species. The values of the population pairwise differentiation index (F_st and Φ_pt) ranged from 0.01 to 0.29. The UPGMA tree showed two diverged genealogical branches corresponding to sampling localities (Clade A = JN, Clade B = ZS and TW) in the species. The AMOVA and STRUCTURE analyses suggested that O. fasciatus may be composed of two stocks in the examined range, and the freshwater discharge from the Yangtze River might act as a physical barrier to genetic exchange between north and south China stocks of the species.

RESPONSIBLE EDITOR:

• Gavin Gouws

KEYWORDS:

• Fluorescent-SSR
• genetic diversity
• genetic structure
• Oplegnathus fasciatus

Acknowledgements

We are grateful to Mr Guangzhao Shao and Peili Lin for collecting samples, and we are grateful to Zimin Hu for his critical comments on the manuscript.

Additional information

Funding

This work was supported by the National Natural Science Fund (41506170, 31172053, 41276166), the 863 (2012AA10A413-1), the STS (No. KFJ-EW-STS-060-STS), the Key Laboratory of East China Sea & Oceanic Fishery Resources Exploitation and Utilization, Ministry of Agriculture, P.R.China, the Promotive Research Fund for Excellent Young and Middle-aged Scientists of Shandong Province (BS2012HZ025), the Guangdong Provincial Key Laboratory of Fishery Ecology and Environment (LFE-2015-8), the Shinan District of Qingdao City Development and Reform Bureau project (20140103) and the Technology Foundation for Selected Overseas Chinese Scholars, Ministry of Personnel of China (2013.01).