速度增量及持续时间对瓦氏黄颡鱼幼鱼临界游泳速度的影响

Effects of velocity increment and duration on critical swimming speed of juvenile darkbarbel catfish

为了考查速度增量（△v）和持续时间（△t）2个参数变化对鱼类临界游泳速度（critical swimming speed,Ucrit）的影响,于25℃条件下,首先以15%临界游泳速度作为△v,设置不同的持续时间（△t：5,10,15,30,60min）;再以20min作为△t,设置不同的速度增量（△v：5%,10%,15%,20%,30%Ucrit）,测定瓦氏黄颡鱼（Pelteobag vachelli）幼鱼的临界游泳速度。结果表明：随△t的增加Ucrit整体呈下降趋势,△t由5min增加至60min,绝对游泳速度（absolute swimming speed,Ua）由（47.4±0.7）cm·s^-1下降至（39.1±1.5）cm·s^-1（P〈0.05）,除15和30min无显著差异外,其余各组间均存在显著差异（P〈0.05）;而△v由5%提高至10%Ucrit,Ua由（44.1±0.6）cm·s^-1显著增加至（47.0±0.4）cm·s^-1（P〈0.05）,15%和20%Ucrit的Ua分别为（45.2±0.2）cm·s^-1和（46.3±0.8）cm·s^-1,与10%Ucrit组之间均无显著差异,但△v增加至30%Ucrit,Ua下降至（41.7±1.2）cm·s^-1,显著低于其他各组水平（P〈0.05）。表明采用不同的△v和△t对瓦氏黄颡鱼幼鱼Ucrit的测定结果存在明显的影响;瓦氏黄颡鱼幼鱼Ucrit测定适宜的△t为15~30min、△v为10%~20%Ucrit。

To investigate the effects of velocity increment and duration on the critical swimming speed（Ucrit）of juvenile darkbarbel catfish（Pelteobag vachelli）,the Ucrit was determined with different velocity increment and duration at water temperature 25 ℃.The fish were first tested at the duration of 5,10,15,30,and 60 min at a velocity increment of 15% Ucrit（1.0 body length）,and then,tested at a velocity increment of 5%,10%,15%,20%,and 30% Ucrit with a duration of 20 min.The Absolute swimming speed（Ua）of experimental fish decreased from（47.4±0.7）cm·s^-1 at 5 min to（39.1±1.5）cm·s^-1 at 60 min（P〈0.05）,but the Ua in 15 min group was not significantly different from that in 30 min group.The Ua increased from（44.1±0.6）cm·s^-1 in 5% Ucrit increment group to（47.0±0.4）cm·s^-1 in 10% Ucrit increment group（P〈0.05）.There were no significant differences in Ua among the groups of 10%,15%,and 20% Ucrit,but the Ua in 30% Ucrit increment group was significantly lower than that in other groups（P〈0.05）.It was suggested that the values of critical swimming speed were profoundly affected by the velocity increment and duration,and the proper duration and velocity increment for darkbarbel catfish were 15-30 min and 10%-20% Ucrit,respectively.