Comparative study on the local populatoins of the East Asian temperate Sea basses

温带底鲈属，鲈科底鲈属，是东亚国家相当常见的商业鱼类。本属在具有35或36个椎体数的家族中是独特的，并且被认为包含了l.a japonicus和l.a latus两个物种。近年来，在日本南部沿海地区鱼苗养殖越来越普遍，许多鱼苗已从中国进口。但是，尽管已知物种之间存在一些地理差异，但尚未对其进行分类审查。因此，我们开始了对日本枇杷地理变异的研究，结果发现了一些非常有趣的关于日本枇杷地理变异的知识。发生在中国和朝鲜半岛西部海岸的种群与发生在日本和朝鲜半岛南部海岸的种群在形态和遗传上应被视为相互独立的物种；前者应为斑马鱼（Lateolabrax maculatus），后者为日本鱼（L.japonicus）。另一件事是，九州北部有明海的一个当地人口，线粒体DNA的基因组成不寻常；80%的个体的单倍型与L.maculatus （Chinese Lateolabrax）相同，20%的个体与L.japonicus相同。这说明有明海的种群可能起源于斑纹l.a maculatus和日本l.a japonicus的杂交种群，这在脊椎动物世界中是非常罕见的。因此，我们需要对有明海的种群进行更深入的研究。

Temperate sea basses, genus Lateolabrax of the Percichthyidae, are quite common commercial fishes in the East Asian countries. This genus is unique among the family in having 35 or 36 vertebral number and has been thought to encompass the two species L.japonicus and L.latus.Recently, acuaculture of L.japonicus has been getting common in the coasts of southern Japan and many juveniles of the species have been imported from China. But, there has been no taxonomic review although some geographic variations among the species have been known. Therefore, we started to study about the geographic variations of L.japonicus.As results of our study, we found some knowledges, which is quite interesting, about the geograhic variations of L.japonicus. The population occurring in the coasts of China and western Korean Peninsula and that in the coasts of Japan and southern Korean Peninsula should be treated as separate species from each other morphologically and genetically ; the former should be Lateolabrax maculatus and the latter L.japonicus. And another thing, one of the local population of Ariake Sea, northern part of Kyushu, has unusual gene composition of mitochandrial DNA ; haplotypes of 80% of the individuals are the same as those of L.maculatus (Chinese Lateolabrax), and those of 20% are the same as those of L.japonicus. This means the population of Ariake Sea may be originated from the hybridyzed population between L.maculatus and L.japonicus, which is quite unusualin the vertebrate world. Therefore, we need more advanced research about the population of Ariake Sea.