三峡蓄水以来葛洲坝下中华鲟产卵场河床质特征变化  

Changes of bottom substrate characteristics in spawning ground of chinese sturgeon downstream the gezhouba dam from impounding of three gorge reservoir

作　　者：杜浩[1] 危起伟[1] 张辉[1] 王成友[1] 吴金明[1] 沈丽[1] 

机构地区：[1]农业部淡水生物多样性保护重点实验室,中国水产科学研究院长江水产研究所,武汉430070

出　　处：《生态学报》2015年第9期3124-3131,共8页Acta Ecologica Sinica

基　　金：国家自然基金青年科学基金项目(31202003);公益性农业行业专项(201203086)

摘　　要：中华鲟是国家一级保护水生动物,是产底层产粘性卵鱼类。河床质构成了中华鲟受精卵和早期胚胎发育的物理环境,其变化可能直接影响中华鲟自然繁殖的规模和效果。基于水声学和水下视频技术对葛洲坝下现存唯一已知中华鲟自然产卵场的河床质特征进行了连续观测,对三峡水库蓄水以来中华鲟自然产卵场的河床质特征变化进行了研究。水声学分析结果显示,2004—2012年间,中华鲟产卵场区域内河床硬度未有明显变化,但粗糙度显著增加(P<0.05)。对产卵位点的河床质特征分析表明,下产卵区的硬度增加(2012年显著高于2008和2004年(P<0.05)),上产卵区硬度呈明显下降趋势(2004年显著高于2008和2012年(P<0.05));上产卵区的河床粗糙度均呈不显著上升趋势(P>0.05);下产卵场区的河床粗糙度呈显著上升趋势(P<0.05)。水下视频观测结果显示,三峡蓄水导致的水体含沙量明显减少,对河床的冲刷日益明显,表现在产卵场江段沉积细砂和粗砂区域面积显著减少,河床卵石缝隙充塞度明显下降(P<0.05)。下产卵区在2007—2012年视频观察过程中发现河床卵石缝隙充分暴露,几乎没有任何细砂或粗砂填充,与上产卵区河床卵石缝隙充塞度特征明显不同。长期观测表明,2004—2012年期间中华鲟自然产卵位点发生了明显的改变,2004—2007年均发生在下产卵区,而2008—2012年均发生在上产卵区,自然繁殖规模和效果也明显下降。综合分析显示,中华鲟产卵场河床质特征的变化可能是导致中华鲟自然产卵位点的改变和迁移的原因,进而影响中华鲟自然产卵场的繁殖适合度,影响中华鲟自然繁殖的规模和效果。对三峡蓄水清水下泄的生态影响评估以及中华鲟自然产卵场的改良或修复有重要借鉴意义。Since 2010,the Chinese sturgeon Acipenser sinensis,one of the first-class national protected animals in China,has been classified as Critically Endangered in the IUCN Red List of Threatened Species. The last spawning ground of the Chinese sturgeon is located just downstream from the Gezhouba dam（ GZD） after its construction,and thus,it is critical to retain the availability of the spawning ground for the sustainability of the species. The riverbed substrate and its surrounding microhabitat supply an environment for survival and development of the embryos of the Chinese sturgeon,and so chronic change to riverbed characteristics could have significant consequences on the reproductive success of the Chinese sturgeon.Based on long-term investigation of the ecological factors linked with natural spawning and especially observation of the spawning substrate characteristics over the last 8 years,the arrangement and structure of the bottom substrate of thespawning ground have been greatly changed from impounding of water in the Three Gorge Reservoir（ TGR）. At the same time,the critically important spawning sites as well as the spawning scale have also changed with spawning events occurring at spawning sites downstream（ SSD） from 2004 to 2007 and spawning sites upstream（ SSU） from 2008 to 2012. The ecological effects of the bottom substrate on spawning success and embryo development of the Chinese sturgeon are still not well documented. To study the effects of bottom substrate characteristics linked to impounding of water in the TGR,acoustic surveys with a scientific echo-sounder（ 2004—2012） and underwater video surveys（ 2007—2012） were conducted in the 6km reaches of the Yangtze river just downstream from GZD including the last spawning ground of the Chinese sturgeon. The echo-sounder surveys showed that great changes in bottom hardness（ as seen in the 1stpart of the 1stBottom Echo from start to peak of the echogram） and roughness（ as seen in the 2ndpart of the 1stBottom Echo from the pe

关 键 词：中华鲟 河床质 粗糙度 硬度 充塞度 

分 类 号：S917.4[农业科学—水产科学]