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

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...

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

To investigate the effects of velocity increment and duration on the critical swimming speed(U_(crit))of juvenile darkbarbel catfish(Pelteobag vachelli),the U_(crit) 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% U_(crit)(1.0 body length),and then,tested at a velocity increment of 5%,10%,15%,20%,and 30% U_(ctit) with a duration of 20 min.The absolute swimming speed(U_(a))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 U_(a) in 15 min group was not significantly different from that in 30 min group.The U_(a )increased from (44.1 ±0.6)cm·s~(-1) in 5% U_(crit) increment group to(47.0 ±0.4)cm·s~(-1) in 10% U_(crit) increment group(P＜0.05).There were no significant differences in U_(a) among the groups of 10%,15%,and 20% U_(crit),but the U_(a) in 30% U_(crit) 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% U_(crit),respectively.