Rivers are dynamic systems where flow is constantly changing, making early fish life stages with lower swimming abilities potentially vulnerable to rapid changes in water velocity. In this study, we evaluated the response of critical young life stages of three Iberian leuciscids – Achondrostoma occidentale, Iberochondrostoma lusitanicum, and Iberochondrostoma almacai – to increasing water velocities, by determining their critical swimming speed (U_crit) and its relation with morphometric traits potentially associated with better swimmers. Results suggest a positive relation between both fish length and body depth with U_crit and species-specific differences in swimming performance. Moreover, most fish could not withstand the maximum velocity tested (20 cm s⁻¹), which can be surpassed in the rivers they occur. This study highlights the importance of considering individual traits for future management of fish stocks in rivers.

中文翻译：

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三种受威胁的伊比利亚鲤科的生命早期阶段的游泳表现

河流是动态系统，流量不断变化，使得处于早期鱼类生活阶段的游泳能力较低，很容易受到水速快速变化的影响。在这项研究中，我们评估了三个伊比利亚leuciscids关键年轻的生命阶段的响应- Achondrostoma西的，Iberochondrostoma lusitanicum和Iberochondrostoma almacai -增加水的速度，通过确定它们的临界游泳速度（ü_暴击）及其与形态性状的相关潜在与更好的游泳者有关。结果表明这两种鱼的长度和体深度之间的正关系ù_暴以及特定种类的游泳成绩差异。此外，大多数鱼无法承受测试的最大速度（20 cm s ^-1），在所出现的河流中可以超过。这项研究强调了考虑个别性状对于河流鱼类种群未来管理的重要性。