Population genetic structure and larval dispersal potential of spottedtail goby Synechogobius ommaturus in the north-west Pacific

Larval dispersal may have an important effect on genetic structure of benthic fishes. To examine the population genetic structure of spottedtail goby Synechogobius ommaturus, a 478 base pair (bp) fragment of the hypervariable portion of the mtDNA control region was sequenced and used to interpret life-history characteristics and larval dispersal strategy. Individuals (n = 186) from 10 locations on the coasts of China and Korea were analysed and 44 haplotypes were obtained. The levels of haplotype and nucleotide diversity were higher in East China Sea populations than in other populations. Both the phylogenetic tree and the minimum spanning tree showed that no significant genealogical structures corresponding to sampling locations existed. AMOVA and pair-wise F-ST revealed significant genetic differentiation between populations from Korea and China. A significant isolation by distance pattern was observed in this species (r = 0 center dot 53, P < 0 center dot 001). Both mismatch distribution analysis and neutrality tests showed S. ommaturus to have experienced a recent population expansion. These results suggest that the Pleistocene ice ages had a major effect on the phylogeographic pattern of S. ommaturus, that larvae might avoid offshore dispersal and that dispersal of larvae may maintain a migration-drift equilibrium.