Allozyme variation was studied in the large-scale mullet Liza macrolepis collected from 4 sites: 3 sites on the west coast of Taiwan, the Tanshui estuary, the Kaohsiung River (Love River) and Dapong Bay (Tungkang); and 1 site about 50 km off the west coast of Taiwan, the Penghu Islands. The genetic similarities among these 4 localities are rather high (0.992-0.999), indicating that they belong to the same population. The inter-sample comparisons of heterozygosity based on 10 polymorphic loci (sAAT-1, CK-B, GPI-A, GPI-B, IDHP-A, LDH-C, sMDH-A, sMDH-B, ME-1 and MPI-1) under the 0.99 criterion revealed that most loci conform with the Hardy-Weinberg Equilibrium, except those at GPI-B from Dapong Bay and IDHP-A from the Tanshui estuary, Analysis of overall mean heterozygosities among 4 inter-sample comparisons revealed that the samples from Dapong Bay and the Tanshui estuary have higher values (0.044 and 0.043, respectively) than those from the Kaohsiung River and Penghu (0,029 and 0.028, respectively), probably due to heavy organic pollution in Dapong Bay and colder temperatures in the Tanshui estuary. Comparisons of overall FST (local subpopulation differentiation) of Dapong Bay with those of the three other locations indicate a moderate genetic differentiation which is mainly contributed by the unusually high allele frequency of the MPI locus, A higher inbreeding coefficient (FlS) in the Dapong sample corresponds to the high inbreeding potential at this site, probably due to its nearly land-locked habitat, which limits the exchange of individual fish between the bay and the open coast.
Population genetics, Allozyme comparisons, Large-scale mullet
