Increasing water temperatures are predicted around the globe, with high amplitudes of warming in Subarctic and Arctic regions where Atlantic cod (Gadus morhua) populations currently flourish. We reconstructed oxygen isotope and temperature chronologies from Icelandic cod otoliths, one of the largest cod stocks in the world, to determine if cod moved or migrated over the last 100 years to avoid increasing water temperatures. For δ¹⁸O_otolith analysis, individual annual growth increments from immature and mature life history stages were micromilled from adult otoliths, which were collected in southern Iceland. Linear mixed-effect models confirmed that stable oxygen isotope time series of immature and mature cod differ significantly between both life stages (p < 0.001). Overall, cod otolith δ¹⁸O was significantly correlated with water temperature (sea surface temperature: p < 0.001, temperature at 200 m depth: p < 0.01), indicating that Atlantic cod were exposed to fluctuating water temperatures during the past 100 years and did not move as a response to increasing ocean temperatures. All of the alternate physical factors that were considered for the isotope-based variation in the temperature exposure of Icelandic cod were rejected.

中文翻译：

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过去100年冰岛鳕（Gadus morhua）种群温度暴露的稳定氧同位素重建。

预计全球范围内水温将升高，目前大西洋鳕鱼（Gadus morhua）种群繁盛的亚北极和北极地区变暖幅度很大。我们从冰岛鳕鱼耳石（世界上最大的鳕鱼种群之一）重建了氧同位素和温度时序，以确定鳕鱼在过去100年中是否迁移或迁移，以避免水温升高。对于δ ¹⁸ Ø_耳石分析表明，从成年的耳石中，细磨了未成熟和成熟生活史阶段的个体年增长量，这些成年耳石是在冰岛南部收集的。线性混合效应模型证实，在两个生命阶段之间，未成熟和成熟鳕鱼的稳定氧同位素时间序列存在显着差异（p  <  0.001）。总体而言，鳕鱼耳石δ ¹⁸ O的显著用水温度（海面温度相关：p  <  0.001，温度在200米的深度：p  < 0.01），表明大西洋鳕鱼在过去100年中处于波动的水温中，并没有响应海洋温度的升高而移动。冰岛鳕鱼温度暴露中基于同位素的变化所考虑的所有其他物理因素均被拒绝。