Li Yangxi, Hou Yiqun, Zhang Ben, Zou Xuan, Johnson David, Wan Fan, Zhou Chaoyan, Jin Yao, Shi Xiaotao
Key Laboratory of Ecological Impacts of Hydraulic-Projects and Restoration of Aquatic Ecosystem of Ministry of Water Resources, Institute of Hydroecology, Ministry of Water Resources and Chinese Academy of Sciences, Wuhan 430079, China.
College of Hydraulic and Environmental Engineering, China Three Gorges University, Yichang 443002, China.
Animals (Basel). 2022 Oct 19;12(20):2844. doi: 10.3390/ani12202844.
The swimming kinematics (how fish move) and dynamics (how forces effect movement) of Schizopygopsis malacanthus were investigated during the determination of Ucrit by stepped velocity testing. A video tracking program was used to record and analyze the motion of five test fish in a Brett-type flume during each velocity step. The findings fell into three groups: (1) Even when flow was uniform, fish did not swim steadily, with speeds fluctuating by 2.2% to 8.4% during steady swimming. The proportion of unsteady swimming time increased with water velocity, and defining steady and unsteady swimming statistically, in terms of the definition of standard deviation of instantaneous displacements, may have higher accuracy. (2) In steady swimming, the forward velocity and acceleration of fish were correlated with body length (p < 0.05), but in unsteady swimming the correlations were not significant. The maximum swimming speed (1.504 m/s) and acceleration (16.54 m/s2) occurred during unsteady swimming, but these measurements may not be definitive because of tank space constraints on fish movement and the passive behavior of the test fish with respect to acceleration. (3) Burst-coast swimming in still water, investigated by previous scholars as an energy conserving behavior, is not the same as the gait transition from steady to unsteady swimming in flowing water. In this study, the axial force of fish swimming in the unsteady mode was significantly higher (×1.21.6) than in the steady mode, as was the energy consumed (×1.273.33). Thus, gait transition increases, rather than decreases, energy consumption. Our characterization of the kinematics and dynamics of fish swimming provides important new information to consider when indices of swimming ability from controlled tank testing are applied to fish passage design.
在通过逐步速度测试确定临界游泳速度（Ucrit）的过程中，对软刺裸裂尻鱼的游泳运动学（鱼类如何移动）和动力学（力如何影响运动）进行了研究。在每个速度阶段，使用视频跟踪程序记录并分析了五条试验鱼在布雷特式水槽中的运动。研究结果分为三组：（1）即使水流均匀，鱼也不能稳定游动，在稳定游泳过程中速度波动幅度为2.2%至8.4%。不稳定游泳时间的比例随水流速度增加，根据瞬时位移标准差的定义从统计学角度定义稳定和不稳定游泳，可能具有更高的准确性。（2）在稳定游泳中，鱼的前进速度和加速度与体长相关（p<0.05），但在不稳定游泳中相关性不显著。最大游泳速度（1.504米/秒）和加速度（16.54米/秒²）出现在不稳定游泳过程中，但由于水槽空间对鱼运动的限制以及试验鱼在加速度方面的被动行为，这些测量结果可能并不确定。（3）先前学者研究的静水中的爆发-滑行游泳作为一种节能行为，与流水环境中从稳定游泳到不稳定游泳的步态转变不同。在本研究中，鱼在不稳定模式下游泳时的轴向力显著高于稳定模式（×1.21.6），能量消耗也是如此（×1.273.33）。因此，步态转变增加而非减少了能量消耗。我们对鱼类游泳运动学和动力学的描述为将受控水槽测试中的游泳能力指标应用于鱼类通道设计时提供了重要的新信息以供参考。
