三峡水库生态调度对沙市江段鱼卵和仔鱼的影响

2012年5-7月三峡水库试验性生态调度期间,在长江中游沙市江段设固定采样点,共采集到鱼卵和仔鱼35种,隶属于4目、8科、10亚科、28属。银鮈(Squalidus argentatus)、歺又鱼(Hemiculter leucisculus)、细鳞鲴(Plagiognathops microlepis)、蒙古鲌(Culter mongolicus mongolicus)、花斑副沙鳅(Parabotia fasciata)、翘嘴鲌(Culter alburnus)、鳊(Parabramis pekinensis)、赤眼鳟(Squaliobarbus curriculus)、草鱼(Ctenopharyngodon idellus)和鲢(Hypophthalmichthys molitrix)构成了该江段的主要繁殖种类。鱼类繁殖盛期在5-6月,进入7月后鱼卵减少而仔鱼数量显著增加。调查期间鱼卵和仔鱼总径流量约为6.89×1010粒(尾),其中鱼卵径流量1.1×1010粒,仔鱼径流量5.79×1010尾。定点采集的鱼卵、仔鱼随采样时间和垂向空间分布均无显著性差异。不同采集点仔鱼的横向分布存在显著性差异,平均漂流密度为江北江中江南;鱼卵的横向分布无显著性差异,且与流速、流态等水力学指标存在负相关性。生态调度期间沙市江段鱼卵总径流量和家鱼卵径流量均出现高峰,繁殖种类明显增加。初步研究表明,三峡水库生态调度制造的涨水过程能够在一定程度上满足不同鱼类自然繁殖的水文需求,对于减缓三峡水库运行对长江中游鱼类自然繁殖的不利影响、维护鱼类种群资源补充具有重要的意义。

Effects of Ecological Operation of Three Gorges Reservoir on Fish Eggs and Larvae in Shashi Section of the Yangtze River

About 35 species of fish egg and larvae belonged to 4 order 8 family 10 subfamily 28 genus were investigated in the Shashi section of mainstream Yangtze River, from May to July 2012, during experimental ecological operation of Three Gorges Reservoir(TGR). More than ten species such as Squalidus argentatus, Hemiculter leucisculus, Plagiognathops microlepis, Culter mongolicus mongolicus, Parabotia fasciata, Culter Alburnus, Parabramis pekinensis, Squaliobarbus curriculus, Ctenopharyngodon idellus, Hypophthalmichthys molitrix were composed of main breeding fishes in the surveyed river reach. The peak of fish breeding period was in May and June, and eggs decreased and larval increased from July. The total runoff of egg and larvae was 6.89×1010 ind., including 1.1×1010 ind. of eggs and 5.79×1010 ind. of larval. The diurnal and vertical distribution had no significant differences both for the egg and larvae. The sectional distribution of larvae had significant difference, while sectional distribution of egg had no significant difference and was negatively related with hydraulic indicators such as velocity and fluid state. The experimental ecological operation which enlarged flow discharge by TGR boosted the large quantity of both total fish eggs and the eggs of four major Chinese carps, which demonstrated the positive effect on facilitating hydrological conditions for the breeding of different fishes. The implement of TGR ecological operation might have long-term significance not only for mitigating impact on fish breeding, but also for maintaining fish recruitment in the middle mainstream of Yangtze River.