Reconstruction of marine fishery resource transitions using environmental DNA analysis of submarine cores

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K19281
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Forestry and Forest Products Science, Applied aquatic science, and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Kuroki Mari 東京大学, 大学院農学生命科学研究科(農学部), 助教 (00568800)
• Project Period (FY): 2017-06-30 – 2020-03-31
• Keywords: 漁業資源 / 海底コア / 環境DNA

Outline of Final Research Achievements

To develop a method for reconstructing historical changes in fishery resources based on eDNA metabarcoding of sea sediment cores, sampling surveys were carried out to collect fishes with a beam trawl net, seawater, and bottom sediment cores in Tokyo Bay, where a long-term benthic ichthyofauna monitoring survey has been conducted. The eDNA metabarcoding detected about 90 fish taxa in the water samples, which is a greater number of species compared to the fish species collected during the 34-years trawling surveys. It was revealed that the pelagic fish and reef fish species were only detected by the eDNA metabarcoding, but the detection sensitivity of eDNA was low for cartilaginous fish. The eDNA of fish taxa was detected from the surface to a depth of several tens of centimeters of the sediment core, suggesting that eDNA might be preserved for a long time considering the sedimentation rate in Tokyo Bay.

Free Research Field

水圏生態学

Academic Significance and Societal Importance of the Research Achievements

東京湾をモデル調査水域に選定し、魚類相の経年変化のデータベースと環境DNA 分析の結果を対照した結果、高い検出力をもつ環境DNAは魚類相推定に有用な手法であることが明らかとなった。本手法を適用することで、調査船の大がかりな採集調査に費やす労力や費用を削減でき、種査定の専門知識や経験のない研究者でも応用可能なことから、学術的価値は高いと位置づけられる。また、環境DNA分析を適用することにより、これまで漁具を用いた採集調査で出現記録のなかった広範な分類群の魚類が網羅的に検出され、希少種や外来種の存在も効率的に把握できたことから、海洋生態系の保全管理にも役立つと考えられる。