ABSTRACT: Thermal stress can directly affect the survival of fishes and indirectly impact fish populations through several processes, including impaired swimming performance. Bigeye chub Hybopsis amblops is a state-endangered species in Illinois and is disappearing in the northern portion of its native range in North America. Limited temperature tolerance information exists on this species. The aim of this study was to define the impacts of 2 acclimation temperatures on the performance and behavior of bigeye chub. To accomplish this, we conducted 2 assays: critical thermal maximum (CT_max) testing for upper thermal tolerance limits, and swimming performance testing for critical swimming speed (U_crit) and burst swimming ability. With a 5°C acclimation temperature increase from 21 to 26°C, the CT_max of bigeye chub increased from 32.8 ± 0.4°C to 36.4 ± 0.9°C. U_crit was not different across acclimation temperatures, and fish from both acclimation groups could swim up to over 10 body lengths (BL) s^-1. Burst swimming duration also did not differ statistically across groups, but bigeye chub from the 26°C group swam 27% longer in duration relative to fish from the 21°C group. Results from this study can help guide the protection and restoration of bigeye chub populations from thermal stressors.

中文翻译：

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适应温度对濒危国家大眼Hybopsis amblops临界热极限和游泳性能的影响

摘要：热应激会直接影响鱼类的生存，并通过多种过程间接影响鱼类种群，包括游泳能力受损。大眼（Bigeye chub）Hybopsis amblops是伊利诺伊州的州濒危物种，并在其北美洲本土范围的北部消失。该物种的温度耐受性信息有限。这项研究的目的是确定两个适应温度对大眼eye的性能和行为的影响。为了实现这一目标，我们进行了2种检测：极限热耐受极限的临界最大热（CT _max）测试和临界游泳速度（U _crit）的游泳性能测试）和爆发式游泳能力。随着5°C的适应温度从21°C升高到26°C，大眼big的CT _max从32.8±0.4°C增加到36.4±0.9°C。在不同的适应温度下，U _crit并无不同，并且两个适应组的鱼都可以游动超过10个体长（BL）s ^-1。各组的爆发游泳时间也没有统计学差异，但是26°C组的大眼游泳时间比21°C组的鱼长27％。这项研究的结果可以帮助指导保护和恢复大眼种群免受热应激源的侵害。