1. Environmental and Community Affairs Department, Nature Conservation Division, Biodiversity Center, Chiba Prefectural Government, Aoba-cho 955–2, Chuo, Chiba 260–8682, JAPAN
2. Wagamehogonokai, Shinke 548–21, Naka, Sakai, Osaka 599–8232, JAPAN
3. NPO Nakaikemi-Net, Kashimagari 7–25, Tsuruga, Fukui 914–0005, JAPAN
4. Devision of Aquatic Environment, Kyoto Prefectural Institute of Public Health and Environment, Murakamicho 395, Fushimi, Kyoto 612–8369, JAPAN