急性降温对青鱼幼鱼游泳能力的影响

Effects of Acute Temperature Declining on Swimming Performance of Juvenile Black Carp

为了研究急性降温对鱼类的行为及代谢的影响,本实验设置25℃→25℃,25℃→15℃,15℃→15℃(驯化温度→实验温度)3个温度组,采用自制鱼类能量游泳装置测定了青鱼(体长8.87±0.75cm,体重11.86±3.60g)临界游泳速度(Ucrit)、耗氧率(MO2)以及疲劳后的恢复耗氧率.研究结果表明:青鱼在3个温度组Ucrit分别是11.32±0.29BL/s、8.04±0.38BL/s和7.73±0.25BL/s,急性降温(25℃→15℃)组的Ucrit是15℃→15℃组的96.2%,降低了3.8%,差异性不显著(P>0.05),急性降温在短时间内抑制青鱼幼鱼游泳速度,影响不显著;MO2随着流速的增加而增大,耗氧率与流速关系分别为25℃→25℃:MO2=49.138U+365.990,R2=0.995;15℃→15℃:MO2=42.886U+315.002,R2=0.972;25℃→15℃:MO2=37.265U+259.987,R2=0.973;随着温度升高,耗氧率增大,急性降温对鱼类的耗氧率有抑制作用;疲劳后继续测定耗氧状况,90min内恢复耗氧率均呈先降低后逐渐趋于平稳,恢复耗氧率分别为25℃→25℃:73.14 mgO2/kg,25℃→15℃:102.47mgO2/kg,15℃→15℃,89.38mgO2/kg.研究表明:急性降温对青鱼幼鱼游泳特性具有显著的影响,并且对其行为产生胁迫作用,研究有利于为鱼道的建设提供数据资料,对鱼类的保护具有重要的意义.

The effects of acute temperature declining（25℃→25℃（A）,25℃→15℃,and 15℃→15℃）were conducted on the critical swimming speed（Ucrit）,oxygen consumption rate（MO2）and excess post-exercise oxygen cost（EPOC）of juvenile black carp（Mylopharyngodon piceus）（Body length：8.87±0.75 cm,body mass：11.86±3.60g）.A stepped velocity test in an intermittent-flow respirometer was applied to examine the different physiological responses of fish on the acute temperature change.The study results show that the relative Ucritof three groups（25℃ →25℃,25℃ →15℃,and 15℃ →15℃）were 11.32±0.29BL/s,8.04±0.38BL/s and 7.73±0.25BL/s respectively.The Ucritof acute temperature declining group（25℃→15℃）is about 96.2%than that of the corresponding acclimation group（P〉0.05）;and the significant difference is negligible.The MO2 increased with increasing swimming speed for the three studied groups which can be expressed by the equations：25℃→25℃：MO2=49.138U＋365.990,R2=0.995;15℃→15℃：MO2=42.886U＋315.002,R2=0.972;25℃→15℃：MO2=37.265U＋259.987,R2=0.973.The MO2 increased profoundly with temperature increase（P〈0.05）;and the acute temperature declining has the inhibitory action on the MO2.The EPOC for 25℃ →25℃,25℃ →15℃ and 15℃ →15℃ within 90 minutes are 73.14 mgO2/kg,102.47mgO2/kg and 89.38mgO2/kg,respectively.The observed results for the selected range of temperature suggest that the physiological and behavioral stress elicited by acute temperature declining is siginificant.This study provides basic information for building fishways and will also be meaningful for biodiversity conservation.