Population structures of four species of the genus Okamejei (Rajiformes; Rajidae) around Japan, inferred from gene sequence variations and morphometric data

Abstract

The population structures of four Japanese species of the rajid genus Okamejei were investigated based on sequence variations in the mitochondrial DNA control region and morphometric data. These suggested that geographic barriers, such as straits and ocean currents, had shaped the population structures on a small spatial scale, the Tsushima Warm Current being particularly significant. This may be related to the limited migration ability of Okamajei species due to their small body size and habitat preference for shallow waters.