Evolutionary genetics of Hawaiian freshwater fish

We surveyed mitochondrial (mt)DNA restriction site variation within each of the five native species of Hawaiian freshwater fishes: Lentipes concolor, Stenogobius hawaiiensis, Sicyopterus stimpsoni, Awaous guamensis, and Eleotris sandwicensis. MtDNA haplotypes did not vary geographically except among samples of S. hawaiiensis, where haplotypes from Maui clustered together. One haplotype in this cluster also was found on Kauai and on Oahu, and one haplotype was found only on Kauai. MtDNA data suggest gene flow among islands, consistent with interisland dispersal through amphidromous larvae. We hypothesize that dispersal has prevented further speciation in these fishes and that colonization of island freshwater habitats by larvae could be independent of natal island.