1. Graduate School of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo 060-0818, Japan
2. Water Research Group, Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
3. Department of Chemistry, College of Natural and Computational Science, University of Gondar, P.O. Box 196, Gondar, Ethiopia
4. Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate 041-8611, Japan
5. Hokkaido National Fisheries Research Institute, Japan Fisheries Research and Education Agency, 2-2-4-1 Nakanoshima, Toyohira-ku, Sapporo 062-0922, Japan