| Affiliation: | 1. Graduate School of Fisheries Sciences, Hokkaido University, , Hakodate, Hokkaido, 041‐8611 Japan;2. National Museum of Nature and Science, , Tsukuba, Ibaraki, 305‐0005 Japan;3. The Institute of Cetacean Research, , Chuo‐ku, Tokyo, 104‐0055 Japan;4. Center for Marine Environmental Studies, Ehime University, , Matsuyama, Ehime, 790‐8577 Japan;5. Shiretoko Museum, , Shari‐gun, Hokkaido, 099‐4113 Japan;6. Faculty of Bio‐Industry, Tokyo University of Agriculture, , Abashiri, Hokkaido, 099‐2493 Japan |
