Bailey Lauren A, Childs Amber Robyn, James Nicola C, Duncan Murray I, Pringle Brett A, Potts Warren M
Department of Ichthyology and Fisheries Science, Prince Albert Street, Makhanda, Rhodes University, Grahamstown 6139, South Africa.
South African Institute for Aquatic Biodiversity, Private Bag 1015, Grahamstown 6140, South Africa.
Conserv Physiol. 2025 Jun 24;13(1):coaf043. doi: 10.1093/conphys/coaf043. eCollection 2025.
Changes in ocean temperature are expected to have a considerable effect on fishes through the impact of temperature on physiological performance, vital energetic processes (i.e. metabolism, foraging and swimming style) and reproductive fitness. To understand the sensitivity of an exploited population of in to temperature variability, intermittent-flow respirometry was used to quantify and compare changes in metabolic rate and aerobic scope under different temperatures (10, 16, 21 and 24°C) mimicking thermal variations experienced in the home range of this species. A total performance score was developed to represent aerobic performance across the range of test temperatures. This score was calculated for each temperature from the lower (25%), mid (50%) and upper (75%) percentiles of the aerobic scope range available for the species. The results of this study identified heterogeneity in physiological performance phenotypes amongst individuals of the exploited population. There was significant variation in the aerobic performance of high, intermediate and low performers at higher temperatures. However, differences in performance were not significant at low temperatures, where several intermediate performers maintained high performance. High performers maintained high rates of physiological performance across a broad range of temperatures, whereas low performers were physiologically limited outside of their optimal thermal range. These results suggest that individuals with a broad aerobic scope (i.e. high aerobic scope (AS) values across a range of temperatures) may likely be the most resilient to short-term thermal variability caused by marine heat waves and upwelling events in temperate coastal environments. Since the shape of thermal performance curves differs between individuals and reflects the range at which individuals can function above specified performance thresholds, individual thermal performance must be measured repeatedly in the same individual over a thermal gradient. An understanding of physiological phenotypic diversity amongst individuals is critical to understand the impacts of thermal variability on fished populations.
预计海洋温度变化将通过温度对生理性能、重要能量过程（即新陈代谢、觅食和游泳方式）以及繁殖适应性的影响，对鱼类产生相当大的影响。为了解某一被捕捞种群对温度变化的敏感性，采用间歇流呼吸测定法来量化和比较在不同温度（10、16、21和24°C）下代谢率和有氧代谢范围的变化，这些温度模拟了该物种栖息地范围内经历的热变化。制定了一个总性能得分来代表整个测试温度范围内的有氧性能。该得分是根据该物种有氧代谢范围的较低（25%）、中间（50%）和较高（75%）百分位数，针对每个温度计算得出的。本研究结果确定了被捕捞种群个体之间生理性能表型的异质性。在较高温度下，高、中、低表现者的有氧性能存在显著差异。然而，在低温下性能差异不显著，有几个中等表现者保持了高性能。高表现者在广泛的温度范围内保持较高的生理性能水平，而低表现者在其最佳热范围之外受到生理限制。这些结果表明，具有广泛有氧代谢范围（即在一系列温度下具有较高的有氧代谢范围（AS）值）的个体可能最能抵御温带沿海环境中海洋热浪和上升流事件引起的短期热变化。由于个体之间热性能曲线的形状不同，并且反映了个体在高于特定性能阈值时能够发挥作用的范围，因此必须在同一个体上通过热梯度反复测量个体热性能。了解个体之间的生理表型多样性对于理解热变化对捕捞种群的影响至关重要。
