恒温和周期性变温对鳊幼鱼自发运动的影响

The Effects of Constant and Diel-fluctuating Temperature Acclimation on the Spontaneous Activity in Juvenile Parabramis pekinensis

鱼类在自然生境中经常会遭遇环境温度变动状况,为考察温度对鱼类自发运动的影响,将鳊(Parabramis pekinensis)幼鱼分别在3个恒温水体(15,20,25℃)和1个周期性变温水体((20±5)℃)中驯化30d后,对实验鱼的自发运动进行20min的拍摄,然后对视频数据进行分析,获取包括运动时间、静止时间、总路程、平均速度、运动时间比、实验水槽外周活动时间、中心活动时间等评价实验鱼自发运动的相关指标。结果显示:各处理组的外周活动时间均显著高于中心活动时间(p<0.05),并且静止时间也显著高于运动时间(p<0.05),但各温度处理组之间的各个自发运动指标均无显著差异。与高温组相比,低温条件下鳊幼鱼运动时间比并未显著下降,这可能与鳊在低温下保持较高的稳定游泳能力和较高的活跃状态有关。

Fish are usually facing the fluctuating temperature in natural water body.The present study was aimed to investigate the effects of diel-fluctuating and constant temperature acclimation on spontaneous activity level in the juvenile Chinese bream（Parabramis pekinensis）.The temperature treatments included three stable temperature groups（15,20,and 25 ℃）and one constant temperature group（（20±5）℃）,and all temperature treatments was acclimated for 30 days.After the acclimation,fish from each group was videoed for 20 minutes and these videos were analyzed to evaluate the spontaneous activity of experimental fish with parameters including activity time,resting time,total movement distance,average swimming speed,percent time spent on moving,time spent on periphery area and time spent on central area.The results of present study showed that there were no significant differences in any of the above mentioned parameters among these temperature treatment groups.However,the time spent on periphery area was significantly longer than the time spent on central area within each of the temperature treatment groups.Furthermore,the resting time was also significantly longer than the activity time within each of the temperature treatment groups.Our study suggests that low temperature acclimated fish showed no decrease of the percent time spent on moving compared to the high temperature acclimated individuals,which might be related to the maintaining of their steady swimming performance to a great extend under low temperature which is not agreed with most of the published data in other cyprinids.