Abstract

We investigated the genetic structure and phylogeographical patterns of Sardinella zunasi in Northwestern Pacific. The mitochondrial DNA control region was sequenced for 77 individuals of S. zunasi from four localities over most of the species range. A total of 215 polymorphic sites (72 parsimony informative) and 69 haplotypes were found in the 77 individuals. Three distinct lineages were detected, which might have diverged in the marginal seas during Pleistocene low sea levels. The demographic history of S.zunasi was examined using neutrality tests and mismatch distribution analysis. The results suggested a late Pleistocene population expansion for S. zunasi. Contrary to homogenization expectation, there were strong differences in the geographical distribution of the three lineages. Analyses of molecular variance and the population statistic Φ_ST also revealed significant genetic structure among populations of S. zunasi. These results indicate that gene flow in S. zunasi is far more spatially restricted than predicted by the potential dispersal capabilities of this species.

Key words: Sardinella zunasi, control region, mitochondrial DNA, genetic structure, Pleistocene.