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.

运动的能量消耗成本高昂。这可能催生倾向于节能运动策略的选择压力，例如采用低能耗游速与高效推进动作。对于游泳的鱼类而言，其行进单位距离所消耗的能量，即运输成本（Cost of Transport，简称COT），与游速呈U型相关关系。推进运动学特征与游速之间的关联可通过斯特劳哈尔数（Strouhal Number，St = fA/U，其中f为尾鳍拍打频率，A为尾尖振幅，单位为米，U为游泳速度，单位为米每秒）进行概括：当0.2<St<0.4时，可实现最大推进效率。大口黑鲈在野外环境中的实际游速通常低于理论上可使其COT最小化的游速区间。这一现象可能反映了其为满足多项相互竞争的功能需求而进行的游速调控，例如实现高效的猎物探测与捕获。在观测到的最低游速条件下，斯特劳哈尔数超出了最优区间。机械与生理层面的约束可能使得鱼类在低速游泳时无法采用具备高效推进性能的斯特劳哈尔数参数。