1. Graduate School of Bioindustry; Tokyo University of Agriculture; 196 Yasaka, Abashiri-shi Hokkaido 099-2493 Japan
2. Marine Wildlife Center of Japan; 8-14-8 Shiomi, Abashirishi Hokkaido 093-0042 Japan
3. Faculty of Bioindustry; Tokyo University of Agriculture; 196 Yasaka, Abashiri-shi Hokkaido 099-2493 Japan
4. Erimo Seal Club, 1-48 Erimo-misaki; Erimo-cho Hokkaido 058-0342 Japan
5. Erimo Ranger Office, Hokkaido Regional Environmental Office, Ministry of the Environment, 1-213 Toyo; Erimo-cho Hokkaido 058-0343 Japan