抄録
Abstract The geographical distribution patterns of two closely-related wrasses, Pseudolabrus eoethinus and P sieboldi, on the Pacific and Sea of Japan coasts of southern Japan were examined. Relative frequencies of the two species were sur-veyed in 53 localities (six bordering the Sea of Japan), based on 586 specimens, 91 photographs and a total of 724 minutes of diving observations. Although the distri-butions of the two species broadly overlapped, P. eoethinus was exclusively distrib-uted along the southernmost parts of the peninsulas projecting into the Pacific Ocean, such as Kii Peninsula and Izu Peninsula, except in some protected areas (e.g. around the Koza River mouth near southernmost Kii Peninsula and within the Shimoda City harbor, southernmost Izu Peninsula). On the other hand, P. sieboldi was exclusively distributed in the innermost parts of bays opening to the Pacific (e.g. Sagami and Osaka Bays), and in the Seto Inland Sea and Sea of Japan. These geographical distribution patterns of the two species suggested that P. eoethinus preferred relatively warm, saline waters strongly influenced by the Kuroshio Cur-rent, whereas P. sieboldi preferred relatively cold, less saline waters not or only weakly influenced by the current. It was inferred that the two closely-related wrasses were able to coexist partly by differences in their preferred habitats.
