Highly active fish in low oxygen environments: vertical movements and behavioural responses of bigeye and yellowfin tunas to oxygen minimum zones in the eastern Pacific Ocean.
Highly active fish in low oxygen environments: vertical movements and behavioural responses of bigeye and yellowfin tunas to oxygen minimum zones in the eastern Pacific Ocean.
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DOI：
10.1007/s00227-023-04366-2
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发表时间：
2024
期刊：
影响因子：
2.4
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中科院分区：
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由于人类活动造成的气候变暖，预计在今后几十年中，公海中的最低含氧量区域的体积将显著增加。由此造成的深海区溶解氧的减少可能对呼吸水的生物产生有害影响，特别是那些代谢率较高的生物，如长嘴鱼、金枪鱼和鲨鱼。然而，很少有人知道自由生活的鱼类如何应对低DO环境，因此，增加OMZ的影响将无法可靠地预测。在这里，我们比较了两个活跃的捕食者（大眼金枪鱼Thunnus obesus和黄鳍金枪鱼Thunnus albacares）的反应，DO在整个东太平洋的深度。使用时间序列数据从267标记的金枪鱼（59,910天）和三维地图的模拟溶解氧，我们发现，黄鳍金枪鱼响应低溶解氧在深度花更多的时间在较浅的，更多的含氧沃茨。相比之下，在温跃层以下更深的地方觅食的大眼金枪鱼在使用水柱方面的变化较小。然而，我们发现，大眼金枪鱼的频率增加了简短的向上垂直漂移，他们进行了四倍时，DO在深度较低，但没有伴随的显着差异的温度，这表明这种行为是驱动的部分需要重新调整后的时间在缺氧沃茨。这些研究结果表明，增加OMZ将影响这些商业上重要的物种的行为，因此，其他具有较高代谢率的水呼吸捕食者可能会面临类似的压力。如果要通过今后的管理行动减轻这些影响，就必须更全面地了解浅水化外护区对中上层鱼类垂直生境利用的影响，这可能会增加它们对水面渔业的脆弱性。在线版本包含补充材料，可通过10.1007/s 00227 -023-04366-2获得。
Oxygen minimum zones in the open ocean are predicted to significantly increase in volume over the coming decades as a result of anthropogenic climatic warming. The resulting reduction in dissolved oxygen (DO) in the pelagic realm is likely to have detrimental impacts on water-breathing organisms, particularly those with higher metabolic rates, such as billfish, tunas, and sharks. However, little is known about how free-living fish respond to low DO environments, and therefore, the effect increasing OMZs will have cannot be predicted reliably. Here, we compare the responses of two active predators (bigeye tuna Thunnus obesus and yellowfin tuna Thunnus albacares) to DO at depth throughout the eastern Pacific Ocean. Using time-series data from 267 tagged tunas (59,910 days) and 3D maps of modelled DO, we find that yellowfin tuna respond to low DO at depth by spending more time in shallower, more oxygenated waters. By contrast, bigeye tuna, which forage at deeper depths well below the thermocline, show fewer changes in their use of the water column. However, we find that bigeye tuna increased the frequency of brief upward vertical excursions they performed by four times when DO at depth was lower, but with no concomitant significant difference in temperature, suggesting that this behaviour is driven in part by the need to re-oxygenate following time spent in hypoxic waters. These findings suggest that increasing OMZs will impact the behaviour of these commercially important species, and it is therefore likely that other water-breathing predators with higher metabolic rates will face similar pressures. A more comprehensive understanding of the effect of shoaling OMZs on pelagic fish vertical habitat use, which may increase their vulnerability to surface fisheries, will be important to obtain if these effects are to be mitigated by future management actions. The online version contains supplementary material available at 10.1007/s00227-023-04366-2.