AZTI, Marine Research, AZTI Basque Research and Alliance, Txatxarramendi ugartea z/g, 48395, Sukarrieta, Bizkaia, Spain.
Marine and Freshwater Research Centre, Atlantic Technological University - Galway City, Wellpark Road, Galway, H91 DY9Y, Ireland.
Mar Environ Res. 2024 Jan;193:106283. doi: 10.1016/j.marenvres.2023.106283. Epub 2023 Nov 23.
The subpopulation and/or contingent structure of Atlantic bluefin tuna (Thunnus thynnus) within the Mediterranean Sea is undefined, leading to uncertainty regarding the best strategy for an effective assessment and management of this highly exploited stock. This study aimed to reconstruct temperatures experienced by Atlantic bluefin tuna during the early life period (<3.5 months) using clumped isotope temperature proxy, an innovative geothermometer for carbonates, that does not require previous knowledge of other environmental parameters such as water oxygen composition. We examined otolith chemistry in fish captured from 3 different areas of the Mediterranean Sea and adjacent waters. We found that mean seasonal temperature estimates from clumped isotopes did not differ significantly from satellite derived and otolith oxygen stable isotopic ratios derived temperatures, except for the central Mediterranean Sea, were clumped isotopes derived temperatures were significantly higher than satellite derived temperatures. However, the sensitivity of the clumped isotope thermometer was found to be lower than that based on oxygen fractionation equation, with high variance observed in the clumped isotopes derived temperature estimates. We also observed that clumped isotope derived temperatures were undistinguishable among bluefin tuna captured in the Gibraltar Strait, the central, and eastern Mediterranean Sea. In this paper, we discuss the major sources of uncertainty in temperature reconstructions using bluefin tuna otoliths.
在地中海中，大西洋蓝鳍金枪鱼（Thunnus thynnus）的亚种群和/或 contingent 结构尚未确定，这导致人们对评估和管理这种高度开发的种群的最佳策略存在不确定性。本研究旨在使用凝聚同位素温度探针对大西洋蓝鳍金枪鱼在早期生命阶段（<3.5 个月）经历的温度进行重建，这是一种用于碳酸盐的创新地热计，不需要先前了解水氧组成等其他环境参数。我们检查了来自地中海和邻近水域 3 个不同区域的鱼类的耳石化学。我们发现，凝聚同位素得出的平均季节性温度估计值与卫星衍生值和耳石氧稳定同位素比值衍生值没有显著差异，但在地中海中部，凝聚同位素衍生值明显高于卫星衍生值。然而，凝聚同位素温度计的灵敏度被发现低于基于氧分馏方程的温度计，凝聚同位素衍生的温度估计值存在很大的方差。我们还观察到，在地中海直布罗陀海峡、中部和东部地中海捕获的蓝鳍金枪鱼之间，凝聚同位素衍生的温度没有区别。在本文中，我们讨论了使用蓝鳍金枪鱼耳石进行温度重建的主要不确定性来源。
