LAUSR

Abstract Acanthopagrus schlegelii is a warm temperate demersal fish, which inhabits the sand-mud substrate or rocky reefs in the coastal waters of Northwest Pacific. A total of 130 samples of Acanthopagrus schlegelii from 5 localities were collected in the present study, and the genetic structure and genetic diversity was analyzed by comparing with other 3 populations based on the mitochondrial control region fragments. The haplotype diversity of A. schlegelii was high with a range from 0.8000 to 0.9803 and the nucleotide diversity was low-to-medium with a range from 0.0069 to 0.0132. No obviously genealogical branches or clusters corresponding to sampling locations were detected both in phylogenetic tree and minimum spanning tree. The AMOVA showed that most genetic variation was apportioned within the populations, and the pairwise F s t values indicated significant differentiation between north group populations and south group populations except for WN population. The results of neutrality test, mismatch distribution and Bayesian Skyline Plot (BSP) analysis indicated that A. schlegelii may have experienced a recent demographic population expansion event. We speculated that the climatic fluctuations during the Quaternary glacial had an important effect on the phylogeographic pattern of A. schlegelii populations, and the current environmental factors and fish behaviour also play an important role in shaping the contemporary phylogeographic pattern of this species.