Institution: | Research Program for Marine Biology and Ecology, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Natsushima 2-15, Yokosuka, 237-0061, Japan E-mail:; Graduate School of Veterinary Medicine, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-0818, Japan; Institute of Cetacean Research, Toyomi-cho, Tokyo 104-0055, Japan; Ocean Research Institute, University of Tokyo, Nakano-ku, Tokyo 164-863, Japan; All-Russian Research Institute for Nature Protection, Moscow, Russia |