2022 Fiscal Year Final Research Report

Elucidation of energy balance and environmental selection during migration of juvenile salmon and prediction of adaptation to global warming

Research Project

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Project/Area Number	20H00428
Research Category	Grant-in-Aid for Scientific Research (A)
Allocation Type	Single-year Grants
Section	一般
Review Section	Medium-sized Section 40:Forestry and forest products science, applied aquatic science, and related fields
Research Institution	The University of Tokyo
Principal Investigator	Kitagawa Takashi 東京大学, 大気海洋研究所, 准教授 (50431804)
Co-Investigator(Kenkyū-buntansha)	白井厚太朗東京大学, 大気海洋研究所, 准教授 (70463908) 峰岸有紀東京大学, 大気海洋研究所, 准教授 (80793588)
Project Period (FY)	2020-04-01 – 2023-03-31
Keywords	サケ稚魚 / 回遊 / 環境DNA / 代謝 / 数理モデル / 餌環境 / 耳石
Outline of Final Research Achievements	The effects of ambient temperature and food availability on the growth of juvenile chum salmon were assessed. By combining the measurements of metabolic performance for growth and activity with a bioenergetics model, the energy allocation for different activities in the juveniles was also estimated. Under high temperatures, juveniles reared at low food levels allocated less than half their energy for growth than those reared at high food levels. These results suggest that high temperature and low food level constrain the growth of juveniles, providing an insight into the effect of the recent increase in warm and low-nutrient water masses on survival of juveniles and catches of adult chum on the Pacific side of Japan.Otolith analysis suggested that the chum salmon species-specific oxygen isotope fractionation equation could be used on reconstruction of temperature history. Environmental DNA analysis also suggested their multiple northward migration routes in the waters off Japan.
Free Research Field	魚類行動生理生態学
Academic Significance and Societal Importance of the Research Achievements	回遊現象を，エネルギー収支という観点から理解し，それに基づき本種の将来の環境適応を予測する試みは，魚類生態学・生命科学・地球環境学の学際領域を発展させるものである。得られた成果は，海洋の施策・立法へむけた重要な基礎的根拠となり，温暖化問題を考慮に入れた21世紀後半の資源管理施策の提言も可能となる。国民一般に温暖化が重要水産生物に及ぼす影響を広く示すことは，消費国の国民すべてが，温暖化が資源問題に直結する社会問題として認識し，消費者自らが軽減にむけ具体的行動を起こすといった国民レベルでの対策を先導することに繋がる。持続可能な開発目標（SGDs）のGoal14にも通じる。