Webb PW
School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI 48109-1115, USA.
J Exp Biol. 1998 Aug;201 (Pt 16):2403-12. doi: 10.1242/jeb.201.16.2403.
Sympatric stream-dwelling river chub (Nocomis micropogon) and smallmouth bass (Micropterus dolomieu) were video-taped swimming in the presence of single cylinders spanning a flume. Fish were acclimated and tested at 13, 18 and 23 degreesC swimming in an increasing-velocity test with single vertically or horizontally oriented cylinders 6.4, 13, 19 or 25 mm in diameter. Cylinder orientation had little effect on entrainment. Both species avoided cylinders at low speeds. At intermediate speeds, some fish entrained on the cylinders, but they were displaced at higher speeds. Entrained fish made no regular swimming motions, but the median and paired fins and the body moved continuously and irregularly. The periodicity of body perturbations decreased and the amplitude increased with current speed. These also increased with cylinder diameter, but the variability was high and differences were not significant. Chub entrained in larger numbers and for longer over a wider range of current speeds and temperatures than bass. Entrainment by chub increased with cylinder diameter up to 13-19 mm, but declined for 25 mm cylinders. Bass did not entrain on 6.4 mm and 25 mm cylinders and showed very little entrainment at 13 and 18 degreesC, but entrainment was similar to that of chub at 23 degreesC.
同域分布的溪流栖息型河鲈（Nocomis micropogon）和小口黑鲈（Micropterus dolomieu）在跨越水槽的单个圆柱体存在的情况下游泳时被录像。鱼在13、18和23摄氏度下进行适应和测试，在递增速度测试中，使用直径为6.4、13、19或25毫米的单个垂直或水平放置的圆柱体游泳。圆柱体的方向对卷入影响很小。两种鱼在低速时都避开圆柱体。在中等速度时，一些鱼被卷入圆柱体，但在较高速度时它们会被冲走。被卷入的鱼没有规律的游泳动作，但中位鳍、成对的鳍和身体会持续且不规则地移动。身体扰动的周期性随着水流速度的增加而降低，幅度增加。这些也随着圆柱体直径的增加而增加，但变异性很高且差异不显著。河鲈在比小口黑鲈更宽的水流速度和温度范围内被卷入的数量更多且时间更长。河鲈的卷入量随着圆柱体直径增加到13 - 19毫米而增加，但对于25毫米的圆柱体则下降。小口黑鲈在6.4毫米和25毫米的圆柱体上不会被卷入，在13和18摄氏度时卷入很少，但在23摄氏度时卷入情况与河鲈相似。
