草鱼快速启动过程的加速—滑行游泳行为

The burst-coast swimming behavior of grass carp( Ctenopharyngodon idellus) during fast-start

以3种不同体长的草鱼为研究对象,在水温(20.00±1.50)℃条件下通过惊吓的方式进行了快速启动过程的加速—滑行游泳行为观察,测定了草鱼的疾冲速度,即实验鱼突然加速达到的最大速度。结果发现,体长为(8.47±0.73)cm(稚鱼)、(17.93±1.27)cm(幼鱼)、(51.24±3.24)cm(亚成鱼)的绝对最大疾冲速度及达到最大疾冲速度所需时间分别为(1.449±0.424)m/s(0.294 s)、(2.359±0.434)m/s(0.294 s)、(2.899±0.457)m/s(0.378 s);相对最大疾冲速度分别为(17.099±5.009)BL/s、(13.156±2.418)BL/s、(5.659±0.891)BL/s;实验鱼达到最大疾冲速度后,均以身体保持直线的方式滑行减速。草鱼的绝对疾冲最大速度随体长的增加而增加;相对疾冲最大速度随体长的增加而减小,且稚鱼的相对疾冲最大速度显著高于亚成体。3种实验鱼的绝对游泳加速度间不存在显著性差异,亚成鱼绝对减速滑行加速度的值显著高于幼鱼和稚鱼,而亚成鱼的相对疾冲游泳加速度和相对减速滑行加速度的值显著小于稚鱼。

To learn capability of grass carp（ Ctenopharyngodon idellus） to cross velocity barrier,laboratory experiments were conducted to test burst-coast swimming performance of grass carp through startle response.In this study,the tested fish were divided into three groups according to their body length：（ 8. 47 ± 0. 73） cm（ small-size）,（ 17.93 ±1. 27） cm（ mid-size） and（ 51. 24 ±3. 24） cm（ large-size）. The experiments were carried out in an environment with natural light and water temperature of（ 20. 00 ± 1. 50） ℃. The results showed that the highest absolute sprinting speeds of fish were（ 1. 449 ± 0. 424） m /s（ achieved in 0. 294 s）,（ 2.359 ±0.434） m/s（ 0.294 s） and（ 2.899 ±0.457） m/s（ 0.378 s） for small-size,mid-size fish and largesize fish respectively; the relative sprinting speeds were（ 17. 099 ± 5. 009） BL /s,（ 13. 156 ± 2. 418） BL /s,and（ 5. 659 ± 0. 891） BL /s,respectively. Fish were observed to slow down to coast by keeping their body straight（ no tail-beat） after fish reached their highest sprinting speeds. Absolute sprinting speed of grass carp was found to increase with body length（ P ＆gt; 0. 05）,while relative sprinting speed decreased as body length increased. Relative sprinting speed of small-size fish was significantly higher than that of large-size fish（ P ＆lt;0. 05）. Absolute acceleration of fish was not affected by size（ P ＆gt; 0. 05）; while the absolute coast deceleration of large-size fish was significantly higher than those of smaller size fish（ P ＆lt; 0. 05）; and the relative burst acceleration and relative coast deceleration of large-size fish were both significantly lower than that of small-size fish（ P ＆lt; 0. 05）.