Hypoxia and climate warming are pervasive stressors in aquatic systems that may have interactive effects on fishes because both affect aerobic metabolism. We explored independent and interactive effects of dissolved oxygen (DO) and temperature on thermal tolerance, behavior, and fitness-related traits of juvenile F1 offspring of the African cichlid Pseudocrenilabrus multicolor. Fish were reared in a split-brood design with four treatments (low or high DO, cool or hot temperature); thermal tolerance, growth, and condition were measured after 1 mo in the rearing treatments, following which behavioral traits were measured over 3.6 mo. Critical thermal maximum was higher in fish reared under hot conditions but was not affected by hypoxia. There was an interactive effect of DO and temperature on agitation temperature (temperature at which fish show behavioral signs of thermal stress) and the thermal agitation window (°C between the onset of agitation and final loss of equilibrium). Fish reared and tested under hot, normoxic conditions showed a higher agitation temperature, while fish reared and tested under hot, hypoxic conditions showed the largest thermal agitation window. Fish grew more quickly in length under hot than cool conditions and more quickly under normoxic than hypoxic conditions. Fish reared under cool, normoxic conditions were characterized by higher condition than other groups. Both cool and hypoxic rearing conditions reduced activity and aggression. These results highlight the importance of integrating physiological tolerance measures with sublethal behavioral effects of hypoxia and high temperature to gain a fuller understanding of species responses to multiple stressors.

中文翻译：

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长期缺氧和升高的水温对赤道丽鱼科鱼行为和热耐受性的独立和交互作用。

缺氧和气候变暖是水生系统中普遍存在的压力源，可能会影响鱼类的相互作用，因为二者都会影响有氧代谢。我们探索了溶解氧（DO）和温度对非洲丽鱼科丽鱼伪仔少年F1代的耐热性，行为和与健身相关的性状的独立和交互作用。将鱼以分巢设计进行养殖，并进行四种处理（低或高溶解氧，低温或高温）；在饲养处理1个月后测量热耐受性，生长和状况，然后在3.6个月以上测量行为特征。在炎热条件下饲养的鱼类的临界热最大值较高，但不受缺氧影响。DO和温度对搅拌温度（鱼显示出热应激行为迹象的温度）和热搅拌窗口（搅拌开始和最终失去平衡之间的°C）有相互作用的影响。在高温常氧条件下饲养和测试的鱼显示出较高的搅拌温度，而在高温低氧条件下饲养和测试的鱼显示出最大的热搅拌窗口。在炎热的条件下，鱼的长度增长更快，而在缺氧的条件下，鱼的生长速度更快。在凉爽，常氧条件下饲养的鱼的状况比其他组更高。凉爽和低氧的饲养条件都降低了活动性和攻击性。