Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
Department of Biological Sciences, Towson University, Towson, MD 21252, USA.
J Exp Biol. 2020 Mar 11;223(Pt 5):jeb217125. doi: 10.1242/jeb.217125.
Juvenile striped bass residing in Chesapeake Bay are likely to encounter hypoxia that could affect their metabolism and performance. The ecological success of this economically valuable species may depend on their ability to tolerate hypoxia and perform fitness-dependent activities in hypoxic waters. We tested whether there is a link between hypoxia tolerance (HT) and oxygen consumption rate ( ) of juvenile striped bass measured while swimming in normoxic and hypoxic water, and to identify the interindividual variation and repeatability of these measurements. HT (loss of equilibrium) of fish (=18) was measured twice collectively, 11 weeks apart, between which was measured individually for each fish while swimming in low flow (10.2 cm s) and high flow (∼67% of critical swimming speed, ) under normoxia and hypoxia. Both HT and varied substantially among individuals. HT increased across 11 weeks while the rank order of individual HT was significantly repeatable. Similarly, increased in fish swimming at high flow in a repeatable fashion, but only within a given level of oxygenation. was significantly lower when fish were swimming against high flow under hypoxia. There were no clear relationships between HT and while fish were swimming under any conditions. Only the magnitude of increase in HT over 11 weeks and an individual's under low flow were correlated. The results suggest that responses to the interacting stressors of hypoxia and exercise vary among individuals, and that HT and change in HT are not simple functions of aerobic metabolic rate.
幼年条纹鲈鱼生活在切萨皮克湾，可能会遇到影响其新陈代谢和性能的缺氧环境。这种具有经济价值的物种的生态成功可能取决于它们在缺氧环境中耐受缺氧和进行依赖于健康的活动的能力。我们测试了在正常氧和低氧水中游泳时，幼年条纹鲈鱼的缺氧耐受能力 (HT) 和耗氧量 () 是否存在联系，并确定了这些测量的个体间变异和可重复性。在 11 周的时间内，我们两次集体测量了 18 条鱼的 HT（失去平衡），在此期间，我们还分别测量了每条鱼在低流量（10.2cm/s）和高流量（约为临界游泳速度的 67%，）下在正常氧和低氧水中游泳时的耗氧量。个体间的 HT 和 差异很大。随着时间的推移，HT 增加，而个体 HT 的等级顺序具有显著的可重复性。同样，在高流量下游泳的鱼的 也以可重复的方式增加，但仅在给定的氧合水平内。当鱼在低氧下逆流游泳时， 显著降低。当鱼在任何条件下游泳时，HT 和 之间没有明显的关系。只有 11 周内 HT 增加的幅度和个体在低流量下的 与其他指标相关。研究结果表明，对缺氧和运动等相互作用的应激源的反应在个体之间存在差异，并且 HT 和 HT 的变化不是有氧代谢率的简单函数。
