饲养状态真鲂(鱼弗)发声的昼夜与季节变化

本文研究了受水温和光周期等自然变化影响的饲养状态真鲂鮄发声的昼夜与季节变化,并研究了实验鱼活动(鱼类游泳次数)的日变化。声音信号的昼夜节律记录发声活动的日常水平(摄食之外的时期),但是每月变化的记录(季节性式型)则在摄食期间进行,因为摄食时声音信号增加,而日常发声活动较不频繁。实验鱼包括雌雄两性,且未达性成熟。真鲂鮄在白天发声多一些,也更活跃。声音为阵发式的,较不频繁(平均值=0.04发声/min每鱼每天)。最少的发声活动出现在晚上,凌晨和黄昏居中(声音的阵发更频繁,但是声音更少),最多的发声活动出现在白天(声音的阵发更频繁,并且含更多数目的声音)。竞争摄食时声音信号的比率不呈现季节性变化(平均值=3.98发声/min每鱼),与温度也不相关,显示出竞争摄食时声音的发出以最大比率进行。敲击声和呼噜声的某些声学特征与温度相关,特别是在较高的温度下呼噜声的节拍间隔急剧下降。敲击声和呼噜声的声音参数中的季节性变化,多数可以解释为发声肌肉和中央声音控制回路的温度效应。

Diel and seasonal variations of sound production in captive grey gurnards Eutrigla gurnardus

I investigated diel and seasonal patterns of sound production in captive grey gurnards subject to natural variations in water temperature and photoperiod.I also examined daily variations in activity(number of fish swimming).Diel rhythms of sound production concerned routine levels of acoustic activity(i.e.outside feeding periods),but monthly recordings(seasonal patterns)were carried out during feeding sessions,when sound production increases,because routine acoustic activity was infrequent.Fish were of both genders and were smaller than mature size.Grey gurnards produced more sounds during the day when they were also more active.Sounds were produced in bouts(bursts)and occurred infrequently(mean=0.04 sounds/min per fish at day time).Fish showed minimum acoustic activity at night,intermediate at dawn/dusk(with sound bursts being emitted more often but with fewer sounds),and maximum during the day(with sound bursts becoming both more frequent and containing a higher number of sounds).Sound production rate during competitive feeding did not present seasonal variations(mean=3.98 sounds/min per fish)and was not correlated with temperature,suggesting that sounds are emitted in a maximum rate in this context.Several acoustic features of the knocks and grunts were temperature dependent,particularly the grunt pulse period,which strongly decreased at higher temperatures.Most seasonal variations in the acoustic parameters of knocks and grunts can be explained by the effect of temperature on sonic muscles and central vocal control circuits.