Yasuhiro Shibasaki1)/Fumio Takizawa2):Department of Marine Science, College of Bioresource Sciences, Nihon University1)/Department of Advanced Aquaculture Science, Faculty of Marine Science and Technology, Fukui Prefectural University2)(日本大学生物資源科学部海洋生物学科1)/福井県立大学海洋生物資源学部先端増養殖科学科2))