急性氨氮胁迫对三湖慈鲷幼鱼行为学的影响

Effects of acute ammonia nitrogen stress on behavior of juvenile Cichlidae

【目的】分析急性氨氮胁迫对三湖慈鲷幼鱼焦虑行为、聚群行为和趋光行为的影响,为三湖慈鲷养殖业的健康发展、观赏鱼行为学研究及科学管理提供参考依据。【方法】使用3个浓度(0、5.00和12.25 mg/L NH4Cl)氨氮胁迫三湖慈鲷幼鱼,观察分析其在不同氨氮浓度水体中的焦虑行为(潜伏时长、穿越鱼缸水平中线总次数和待在鱼缸上半部总时间)、聚群行为(延迟离开鱼群穿越鱼缸垂直中线所需时间、转换次数和远离鱼群总时间)和趋光行为(单尾幼鱼在鱼缸不同亮度区域的停留时间和多尾幼鱼在鱼缸不同亮度区域的停留数量)。【结果】焦虑行为试验结果显示,随着氨氮胁迫浓度的升高,三湖慈鲷幼鱼第一次穿越鱼缸水平中线的潜伏时间明显缩短,穿越鱼缸水平中线的次数显著增加(P<0.05,下同),从鱼缸下半部过渡到上半部并停留在上半部的时间显著延长,表现出对氨氮胁迫的焦虑行为,其中以12.25 mg/L浓度组幼鱼的急躁不安更明显;聚群行为试验结果表明,随着氨氮胁迫浓度的升高,三湖慈鲷幼鱼延迟离开鱼群穿越鱼缸垂直中线所需时间显著缩短,穿越鱼缸垂直中线的次数显著增加,从鱼缸下半部过渡到上半部并停留在上半部的总时长显著延长,表现出对氨氮胁迫的离群行为;趋光行为测试结果表明,个体试验中对照组(CK,0 mg/L)三湖慈鲷幼鱼选择鱼缸暗区、过渡区和亮区的停留时间百分比分别为90.16%、5.67%和4.17%,群体试验中CK三湖慈鲷幼鱼选择鱼缸暗区、过渡区和亮区的数量百分比分别为83.00%、12.00%和5.00%,而水体中氨氮胁迫浓度为5.00和12.25 mg/L时,三湖慈鲷幼鱼的趋光性未发生显著变化(P>0.05),说明三湖慈鲷幼鱼具有明显的负趋光行为。【结论】水体氨氮胁迫浓度为5.00和12.25 mg/L时,三湖慈鲷幼鱼均表现出焦虑行为和离群行为,尤其是氨氮浓度在12.25mg/L时表现更焦虑;当水体中氨氮浓度为5.00和12.25mg/L时,三湖慈鲷幼鱼的负趋光性未受明显影响。因此,建议三湖慈鲷幼鱼人工饲养水体的氨氮浓度不宜超过5.00 mg/L。

【Objective】The purpose of the study was to analyze the effects of acute ammonia nitrogen stress on anxiety behavior,clustering behavior and phototaxis behavior of juvenile Cichlidae,so as to provide a reference basis for the healthy development of Cichlidae aquaculture industry and the behavioral research and scientific management of Cichli-dae.【Method】Three different concentrations of ammonia nitrogen(0,5.00 and 12.25 mg/L NH4Cl)were used to stress the juvenile Cichlidae,and their anxiety behavior(latency time,total number of horizontal midline crossings,and total time spent in the upper half),clustering behavior(delayed time taken to leave the school of fish crossing the vertical midline,number of transitions,and total time spent away from the school of fish),and phototaxis behavior(residence time of individual juveniles in different brightness areas and residence number of multiple juveniles in different brightness areas)were observed and analyzed in the water body with different ammonia nitrogen concentrations.【Result】The experi-mental results of anxiety behavior showed that,with the increase of ammonia nitrogen stress concentration,the latency time of the juvenile Cichlidae first crossing of the fishtank horizontal midline was greatly shortened,and the number of times of crossing the fishtank horizontal midline was significantly increased(P<0.05,the same below).With the increase of ammonia nitrogen stress concentration,the time of transition from the fishtank lower half to the upper half and staying in the upper half was significantly longer.The juvenile Cichlidae exhibited anxious behavior in response to ammonia nitro-gen stress,with impatience more pronounced in the 12.25 mg/L concentration group.The experimental results of clus-tering behavior showed that the time taken by the juvenile Cichlidae to leave the school of fish crossing the fishtank verti-cal midline was shortened with the increase of ammonia nitrogen stress concentration.Meanwhile,the number times of crossing the fishtank vertical midline increased significantly,and the time of transition from the fishtank lower half to the upper half and staying in the upper half was significantly longer.The juvenile Cichlidae exhibited straying behavior in re-sponse to ammonia nitrogen stress.The experimental results of phototaxis showed that the percentages of residence time of control group(CK,0 mg/L)of juvenile Cichlidae in the individual experiment were 90.16%,5.67%and 4.17%for se-lecting the fishtank dark area,transition area and light area respectively.The population experiment showed that the percentages of the number of juvenile Cichlidae in the CK selecting the dark area,transition area and light area were 83.00%,12.00%and 5.00%respectively.The phototaxis of juvenile Cichlidae did not change significantly(P>0.05)at the ammonia nitrogen stress concentrations of 5.00 and 12.25 mg/L in the water body,indicating that juvenile Cichlidae had obvious negative phototaxis behavior.【Conclusion】When the ammonia nitrogen stress concentrations in the water body are 5.00 and 12.25 mg/L,the juvenile Cichlidae show anxious behavior and straying behavior,and they show more anxious behavior when the ammonia nitrogen concentration is 12.25 mg/L.When the ammonia nitrogen concentrations in the water body are 5.00 and 12.25 mg/L,the negative phototaxis of the juvenile Cichlidae is not greatly affected.Therefore,it is recommended that the ammonia nitrogen concentration in the water body of juvenile Cichlidae in artificial rearing should not exceed 5.00 mg/L.