Data from: Field swimming behavior in largemouth bass deviates from predictions based on economy and propulsive efficiency

Locomotion is energetically expensive. This may create selection pressures that favor economical locomotor strategies, such as adoption of low cost speeds and efficient propulsive movements. For swimming fish the energy expended to travel a unit distance, or cost of transport (COT), has a U-shaped relationship to speed. The relationship between propulsive kinematics and speed summarized by the Strouhal number (St = fA/U, where f is tail beat frequency, A is tail tip amplitude in m and U is swimming speed in m s<SUP>-1</SUP>) allows for maximal propulsive efficiency where 0.2<St<0.4. Largemouth bass adopted field speeds that were generally below the range predicted to minimize their COT. This may reflect speed modulation to meet competing functional demands such as enabling effective prey detection and capture. St exceeded the optimal range for the lowest observed swimming speeds. Mechanical and physiological constraints may prevent adoption of efficient St during low-speed swimming.运动的能量成本高昂，这可能会施加选择压力，促使生物倾向于采用更经济的运动策略，例如选择低能耗运动速度与高效推进动作。对于游泳的鱼类而言，其移动单位距离所消耗的能量，即运输成本（cost of transport, COT），与运动速度呈U型关系。推进运动学特征与运动速度之间的关系可通过斯特劳哈尔数（Strouhal number, St = fA/U，其中f为尾拍频率，A为以米为单位的尾尖振幅，U为以米每秒（m·s⁻¹）为单位的游泳速度）进行概括，当0.2<St<0.4时，可实现最大推进效率。大口黑鲈（Largemouth bass）在自然环境中采用的运动速度通常低于被预测为可最小化其COT的速度区间。这或许反映了其为满足竞争性功能需求而进行的速度调控，例如实现有效的猎物探测与捕获。在观测到的最低游泳速度下，斯特劳哈尔数超出了最优区间。机械与生理约束可能会阻碍其在低速游泳时采用高效的斯特劳哈尔数工况。