Affiliations:
1Graduate School of Human Development and Environment,
Kobe University: 3-11, Tsurukabuto, Nada-ku, Kobe City, Hyogo 657-8501,
Japan
2Research Fellow of Japan Society for the Promotion of
Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083, Japan
3Maizuru Fisheries Research Station, Kyoto University:
Nagahama, Maizuru, Kyoto 625-0086, Japan