Abstract
In this study, population genetic structure and genetic diversity of round herring in the Turkish seas were determined using sequence data of mitochondrial DNA control region. Round herring, Etrumeus golanii samples were collected from three localities along the Turkish coast of the Mediterranean Sea, (Gulf of Iskenderun and Gulf of Antalya) and southern Aegean Sea (Gulf of Marmaris). Genetic variability was high both within and between the populations based on haplotype diversity values. The results have shown that each population has a high genetic diversity with unique mtDNA haplotypes with unique genetic structure. The most important factor in the emergence of this situation is that populations were considered to have migrated from the Red Sea to the Mediterranean Sea by different fish shoals at different time intervals independently of each other. A general acceptance for explanation of high genetic diversity in the Mediterranean Lessepsian species is the lack of bottleneck due to the consecutive invasions.