漂着ディスポーザブルライターの流出地と 漂着地の関係から求めた日本沿岸における漂流物の流れ

Flow and sources of marine litter washed upon the coast of Japan were estimated using the disposable lighter because it has the outflow information of country or location. The outflow country can be classified by a body shape and punched codes on the tank bottom, and the outflow location can be distinguished by a shop address or telephone number printed on the tank surface. From Aug. 2003 to Mar. 2014, total 63, 140 lighters were collected on the total 1,434 beaches（1,384 in Japan, 36 in Taiwan, 9 in Korea, 4 in Russia and 1 in China）. Flow of lighters elicited by the relation ship the outflow location with the collected site was as follows: The lighters flowed out of the Chinese coast from Hong Kong to Shanghai and the west coast of Taiwan mainly wash upon the remote islands area from Yonaguni Island （Okinawa prefecture） to Amami Islands （Kagoshima prefecture） while drifting north ward in the East China Sea, and they inflow to Japan Sea through the Tsushima Strait. A little number of lighters flowed out of western Korea drift southward, however Korean lighters mostly inflow to Japan Sea. The lighters flowing into Japan Sea directly and through the strait drift northward and then outflow to the Pacific Ocean through the Tsugaru Strait. They drift southward along the Tohoku Pacific coast and reach to the area off Ibaraki prefecture. The lighters drifted northward along the west coast of Hokkaido reach to the area off Shiretoko Peninsula in Okhotsk Sea through the Soya Strait. On the pacific coasts from the southern Kyushu to Tokai area, the lighters flowed out of the around inland area mainly wash up. These flows illustrated by the movement of lighters are basically consistent with the ocean currents around Japan reported in previous oceanographic studies.