Assessment of the experienced environmental stress of fish by using otolith microchemistry

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K21328
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 40:Forestry and forest products science, applied aquatic science, and related fields
• Research Institution: Tokyo University of Marine Science and Technology
• Principal Investigator: Yamamoto Yoji 東京海洋大学, 学術研究院, 准教授 (10447592)
• Co-Investigator(Kenkyū-buntansha): Strussmann C.A. 東京海洋大学, 学術研究院, 教授 (10231052)
• Project Period (FY): 2020-07-30 – 2023-03-31
• Keywords: 環境ストレス / 海洋汚染物質 / 耳石 / 元素含有量 / トウゴロウイワシ

Outline of Final Research Achievements

In this study, we tested the possibility of using elemental information chronologically accumulated across fish otolith increments to reveal past exposure of fish to environmental contaminants. Tributyltin chloride (TBT) and UV-P at different concentrations were used as environmental pollutants and juvenile silversides were used as test fish. After a 7-day pollutant exposure period, otolith trace elements were measured in areas formed before, during, and after exposure using an electron probe microanalyzer. A concentration-dependent increasing trend was observed for K and Na in the TBT exposure group whereas the opposite was observed for the same elements in the UV-P exposure group. These results suggest that elemental information permanently stored in otolith increments may be useful for the assessment of past exposure to environmental pollutants in fish.

Free Research Field

魚類繁殖生理・魚類繁殖生態学

Academic Significance and Societal Importance of the Research Achievements

魚類の耳石は年齢査定に利用されることが多いが、本課題では耳石輪紋の中に時系列に蓄積される微量元素量変動と各種環境汚染物質曝露の因果関係を調査することで、野生魚が経験した汚染物質暴露情報の抽出技術開発を目指した。本研究により、特定の汚染物質に対して耳石内の各種元素が特徴的に増減する可能性が示され、より多くの環境汚染物質やその他環境ストレスと耳石の元素変動の因果関係を調査することで、野生魚の汚染物質曝露情報を抽出可能であることが示された。魚類の食資源としての安全・安心な利用のためには、種々の環境汚染物質が魚類に与える様々な悪影響の評価技術の確立が急務であり、本課題はその実現に寄与する。