布哈河青海湖裸鲤鱼苗鱼卵的时空分布研究

2008年7月1日到10月7日,使用水文过河缆道及圆锥网接滤过式集苗器进行采样,对青海湖布哈河鱼类早期资源的时空分布进行了研究,以期了解青海湖裸鲤的自然繁殖状况,为其资源监测及生态保护提供基础性资料.结果表明:布哈河中鱼类早期资源种类单一,主要为青海湖裸鲤,采样期间有多次苗汛,主要苗汛出现于7月份,9月上旬仅有小规模苗汛;鱼苗平均密度3.17 ind.·m~(-3),最高达54 ind.·m~(-3);晚上鱼苗密度(22:00-22:10)与下午鱼苗密度(14:00-14:10)有显著性差异(df=98,P＜0.05);青海湖裸鲤的鱼卵在上层平均密度为0.075 ind.·m~(-3),下层平均密度0.175 ind.·m~(-3),两者亦存在显著性差异(df=10,p＜0.05);鱼苗的漂流运动主要集中在晚上;总体上看,鱼苗主要分布在河流上层,有近岸分布的趋势,而鱼卵则主要分布在河流下层,接近河流中央位置;鱼苗断面系数为0.43,鱼卵断面系数为2.32.

Spatial and temporal distribution of Gymnocypris przewalskii larvae in the Buha River of the Qinghai Lake

Spatial and temporal distribution of fish larvae in the Buha River,Qinhai Lake was investigated from 1 July to 6 October,2008 by sampling with hydrographic cableways and conical nets.The results showed that almost all fish larvae were Gymnocypris przewalskii.Fish fry mainly appeared in July,with the average density of 3.17 ind.·m~(-3),and max density of 54 ind.·m~(-3).There were significant differences in the density between the day from 14:00 to 14:10 and the night from 22:00 to 22:10(a=0.05,F=6.13,P=0.014).Fish larvae mainly drifted in the night,and fish fry mostly distributed near the surface and the density of fish fry near shore Was higher than the density in river center,while fish eggs mostly distributed near the bottom of river.The density of fish eggs was significantly different,with 0.075 ind.·m~(-3) in the surface,while 0.175 ind.·m~(-3) in the bottom(n=11,F=4.73385,P=0.04174).Sectional coefficient of fish fry and fish eggs was 0.43 and 2.32 respectively.It is very important to understand the characteristics of spatial and temporal distribution of Gymnocypris przewalskii for larval resource investigation and protection.