Studies of historical catches suggest several resident groups once existed in the North Pacific—the Baja California group and the Yellow Sea–East China Sea (including Ryukyu Islands and western Kyusyu) group. Additionally, respective groups in northern Sea of Japan and the group along Pacific coasts of Japan from Hokkaido to Sanriku might have been resident or less migratory, as well. The only modern record among Ryukyu Islands was of a rotten carcass beached on Ishigaki Island in 2005. Regarding Yellow Sea, a juvenile was accidentally killed along Boryeong in 2014.