Morphological and genetic characteristics of sea bass, Lateolabrax japonicus, from the Ariake Sea, Japan

Sea bass, Lateolabrax japonicus, from the Ariake Sea, characterized by black dots on the lateral body region as in the Chinese sea bass, L. sp., were examined and compared morphologically and genetically with L. japonicus and L. sp. Some meristic characters of the Ariake form tended to fall midway between values for the two former species. Genetic features, evaluated by isozyme analyses, indicated that the Ariake form as represented a simple Mendelian population, there being no significant differences from a Hardy-Weinberg equilibrium according to chi-square tests. Although some extreme differences in allelic frequencies were found at some loci between L. japonicus and L. sp., the Ariake form possessed many heterozygotes at the PROT-1* locus, in addition to allelic frequencies at some loci conforming to those of L. sp. Average allele numbers per locus, rate of polymorphic loci and average heterozygosity of the Ariake form were higher than for either L. japonicus or L. sp., indicating high genetic variation in the former. The results suggested that the Ariake population is genetically independent of other populations of L. japonicus, but might be genetically influenced by L. sp.