Reconstruction of abundance of small pelagic species using sedimentary DNA

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K20045
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Environmental analyses and evaluation and related fields
• Research Institution: Ehime University
• Principal Investigator: Michinobu Kuwae 愛媛大学, 沿岸環境科学研究センター, 准教授 (70448380)
• Co-Investigator(Kenkyū-buntansha): 土居 秀幸 兵庫県立大学, シミュレーション学研究科, 准教授 (80608505)
• Project Period (FY): 2017-06-30 – 2020-03-31
• Keywords: 環境DNA / 海洋堆積物 / 魚類個体数 / 長期動態

Outline of Final Research Achievements

Far too little is known about the long-term dynamics of populations for almost all macro-organisms. Here, we examined the utility of sedimentary DNA techniques to reconstruct the dynamics in the “abundance” of a species, which has not been previously defined. We used fish DNA in marine sediments and examined whether it could be used to track the past dynamics of pelagic fish abundance in marine waters. Quantitative PCR for sedimentary DNA was applied on sediment-core samples collected from anoxic bottom sediments in Beppu Bay, Japan. The DNA of three dominant fish species (anchovy, sardine, and jack mackerel) were quantified in sediment sequences spanning the last 300 years. Temporal changes in fish DNA concentrations are consistent with those of landings in Japan for all three species and with those of sardine fish scale concentrations. Thus, sedimentary DNA could be used to track decadal-centennial dynamics of fish abundance in marine waters.

Free Research Field

古環境学・古生物学・古海洋学

Academic Significance and Societal Importance of the Research Achievements

本研究では、環境DNA技術を駆使して魚の個体数の長期変動が堆積物中のDNA量から捉えられることを世界で初めて検証することに成功しました。本研究で用いた堆積物DNAテクノロジーが他の地域にも適用されれば、いまだ地球上のほとんどのマクロ生物種でわかっていない個体群の長期動態の解明につながると期待されます。
今後、こうした堆積物DNA技術は21世紀のマクロ生物モニタリングを支える有用な技術として世界中で利用されることが期待されます。また、過去の気候変動や人為撹乱による環境変動に対する生物の応答を詳しく調べることで、より確かな生物種の動態予測、生態系変化予測につながることが期待されます。