Investigation of radiocesium transfer using metabarcoding diet analysis in freshwater fish

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K12141
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 63010:Environmental dynamic analysis-related
• Research Institution: National Institute for Environmental Studies
• Principal Investigator: Ishii Yumiko 国立研究開発法人国立環境研究所, 福島地域協働研究拠点, 主任研究員 (00620402)
• Co-Investigator(Kenkyū-buntansha): 和田 敏裕 福島大学, 環境放射能研究所, 准教授 (90505562)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 淡水魚 / ヤマメ / 放射性セシウム / 食物網

Outline of Final Research Achievements

We analyzed the diet of Oncorhynchus masou contaminated with radiocesium after the Fukushima Daiichi nuclear power plant accident using DNA metabarcoding method. The diet composition varied with the season and the size of the O. masou, with larger O. masou having a higher proportion of terrestrial insects in their diet. Additionally, to evaluate the bioavailability of radiocesium (the transfer rate from the digestive tract content to body tissues) in the diet, we examined the radiocesium concentrations in digestive tract contents and muscle tissues of various freshwater fish species, including O. masou. The results indicated that larger fish had higher 137Cs concentrations in their muscle compared to their digestive tract contents, suggesting that they consume prey containing 137Cs with higher bioavailability.

Free Research Field

放射生態学

Academic Significance and Societal Importance of the Research Achievements

本研究の結果は、福島県において放射性セシウム汚染により利用が制限されているヤマメの陸域・水域からの放射性セシウム取込み経路を推定するための基礎的な知見を提供するものであり、ヤマメ淡水魚の放射性セシウム濃度の将来推定や汚染管理につながると期待される。また、DNAメタバーコーディングを用いたヤマメ食性解析手法の開発により、消化管内容物の形態観察に比べより幅広い分類群、高い解像度で餌生物の季節や体サイズ依存性が明らかになり、生態学的にも興味深い結果が得られた。