2018 Fiscal Year Final Research Report

Practical approach for establishment of mass production techniques of glass eel seedlings for aquaculture

Research Project

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Project/Area Number	26252030
Research Category	Grant-in-Aid for Scientific Research (A)
Allocation Type	Single-year Grants
Section	一般
Research Field	Aquatic bioproduction science
Research Institution	Nihon University
Principal Investigator	TSUKAMOTO Katsumi 日本大学, 生物資源科学部, 教授 (10090474)
Co-Investigator(Kenkyū-buntansha)	足立伸次北海道大学, 水産科学研究院, 教授 (40231930) 金子豊二東京大学, 大学院農学生命科学研究科(農学部), 教授 (70221190) 坂本崇東京海洋大学, 学術研究院, 教授 (40313390) 朝比奈潔日本大学, 生物資源科学部, 教授 (10147671) 杉田治男日本大学, 生物資源科学部, 教授 (50139052) 黒木真理東京大学, 大学院農学生命科学研究科(農学部), 助教 (00568800) 大竹二雄東京大学, 大学院農学生命科学研究科, 教授 (20160525)
Research Collaborator	IJIRI Shigeho WATANABE Soichi ITOI Shiro
Project Period (FY)	2014-04-01 – 2019-03-31
Keywords	ウナギ / 種苗生産 / 催熟 / レプトセファルス / 飼育技術
Outline of Final Research Achievements	To establish artificial mass production technique of glass eels, both applied and fundamental aspects of the problems on egg quality, larval diet, rearing system and breeding were investigated. Independent solo culture conditions for juveniles could induce natural female differentiation. Abnormal maternal mRNA localization in eggs caused low egg quality even if there is no difference in mRNA level. Feeding behavior of larva was evoked by the stimulants for taste sensing cells which were localized mainly at the lip. Expressions of taste sensing-related genes identified in this study varied in response to the developmental and nutritional status of larvae. The low viscosity of larval diet enhanced feeding and swallowing food by larvae. Breeding effect was confirmed by the individuals with high breeding values detected only in the strain of the fourth generation of artificially produced glass eels. These results would promote the seed production technique for eel aquaculture.
Free Research Field	海洋生命科学
Academic Significance and Societal Importance of the Research Achievements	ウナギの種苗生産技術の確立のために避けて通れない卵質問題の改善，仔魚の初期餌料の開発，飼育方法の改良，優良家系の作出について，基礎・応用の両面で数多くの重要な知見が得られた．ニホンウナギの資源は近年大きく減少し，国際自然保護連合の絶滅危惧種にも指定された．今回の研究による成果は，長年待ち望まれてきた人工シラスウナギの完全養殖技術の完成を大きく加速し，天然のシラスウナギ資源に依存しない持続的なウナギ養殖への道を拓いた．