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

2017 Fiscal Year Final Research Report

• 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
• 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

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.

Free Research Field

水産海洋学