1. Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan
2. Noboribetsu Marine Park Nixe, Noboribetsu, Hokkaido 059-0492, Japan
3. Rakuno Gakuen University, 582 Bunkyodai-Midorimachi, Ebetsu, Hokkaido 069-8501, Japan
4. Azabu University, Sagamihara, Kanagawa 252-5201, Japan