Estimation of spawning temperature for bluefin tuna using oxygen stable isotope ratio

• Project/Area Number: 16K14968
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Aquatic bioproduction science
• Research Institution: The University of Tokyo
• Principal Investigator: Kimura Shingo 東京大学, 大学院新領域創成科学研究科, 教授 (90202043)
• Research Collaborator: HANE Yulina
• Project Period (FY): 2016-04-01 – 2018-03-31
• Project Status: Completed (Fiscal Year 2017)
• Budget Amount: ¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000); Fiscal Year 2017: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000); Fiscal Year 2016: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
• Keywords: クロマグロ / 酸素同位体比 / SIMS / 温暖化 / 耳石 / イオンビーム / 産卵水温 / 水産学 / 行動生態学 / マグロ / 安定同位体比分析 / 産卵海域 / 環境学 / 安定同位体比

Outline of Final Research Achievements

We developed a sample preparation protocol for SIMS measurements in which a sample is polished using different sized diamond pastes until an otolith core is exposed with a mirror surface. We measured δ18O from the core to the edge of 5 otolith samples by SIMS. The results showed more than 1‰ (PDB) increase in δ18O value around the first annuli where an individual experiences first winter. This result likely reflects the actual fluctuation in temperature experienced by fish. The sample preparation protocol developed in the present study thus adequately ensures the quality of SIMS measurements.

Research Products

• [Presentation] Estimating spawning temperature of Pacific bluefin tuna using otolith δ18O by SIMS (2017)
  • Author(s): Hane Y., Kimura S., Yokoyama Y., Miyairi Y., and Ushikubo T.
  • Organizer: Joint Symposium on Ocean Coastal, and Atmospheric Sciences
  • Int'l Joint Research
• [Presentation] Development of methodology for analyses of larval ambient water temperature of Pacific bluefin tuna using SIMS (2017)
  • Author(s): Hane Y., Kimura S., Yokoyama Y., Miyairi Y., and Ushikubo T.
  • Organizer: PICES-2017 Annual Meeting
  • Int'l Joint Research
• [Presentation] The application of SIMS δ18O analysis for estimating spawning temperature of Pacific bluefin tuna using otolith (2017)
  • Author(s): Hane Y., Kimura S., Yokoyama Y., Miyairi Y., Ushikubo T., and Ogawa N.
  • Organizer: 6th International Otolith Symposium. National Museum of Marine Science & Technology
  • Int'l Joint Research