1. Taiji Whale Museum, Taiji, Higashimuro, Wakayama 649-5171, Japan
2. Department of Marine Biology and Sciences, School of Biological Sciences, Tokai University, Minami-ku, Sapporo, Hokkaido 005-8601, Japan
3. Cetacean Research Center, Graduate School of Bioresources, Mie University, Kurimamachiya, Tsu, Mie 514-8507, Japan