长江中游水温节律变化对四大家鱼生殖周期的影响及其调控机制

The operation of the Three Gorges Reservoir has significantly altered the water temperature regime in downstream reaches with raising the water level, which have significantly affected the reproduction of the four major Chinese carps by delaying spawning and declining egg abundance. Therefore, it has important scientific and ecological significance to explore the effects of water temperature regime alteration on reproductive cycle in four major Chinese carps in the middle reaches of Yangtze River under operating Three Gorges Reservoir. This study concerns how the water temperature regime alteration acts on the reproductive axis (hypothalamus-pituitary-gonad axis) of four major Chinese carps under operating Three Gorges Reservoir, based on the researches under the cellular, molecular and individual level through field investigation and indoor simulation experiment. And this study reveals the periodic variation profiles of the gonad development and the key reproductive hormones of four major Chinese carps under the water temperature regime alteration. So we can establish the relationship between the water temperature regime alteration and the negative effect of four major Chinese carps breeding, which reveals the asynchrony between native fish reproduction rhythm and water temperature rhythm and its reproductive regulation mechanism. As a result, this study maybe provide some scientific data for the stock enhancement and the reservoir eco-dispatch of four major Chinese carps.

随着蓄水水位不断提升三峡水库蓄水运行改变下游水温节律，导致四大家鱼等鱼类的繁殖受到显著性影响，繁殖时间不断推迟，产卵规模严重缩小。因此，研究三峡水库运行背景下长江中游水温节律变化对四大家鱼生殖周期的影响，具有重要的科学意义和生态学价值。本研究通过野外调查和室内模拟实验结合，在分子水平、细胞水平和个体水平，研究在三峡水库运行背景下长江中游水温节律改变如何作用于四大家鱼生殖轴（下丘脑-垂体-性腺轴），解析四大家鱼对水温节律改变响应的性腺发育和关键生殖相关激素周期性变化模式。建立水温节律改变与四大家鱼的繁殖之间内在联系，揭示土著鱼类生殖节律与水温节律的不同步性及其生殖调控机理。进而为四大家鱼等鱼类的人工增殖放流和水库生态调度等提供科学依据。

随着蓄水水位不断提升三峡水库蓄水运行改变下游水温节律，导致四大家鱼等鱼类的繁殖受到显著性影响，繁殖时间不断推迟，产卵规模严重缩小。因此，研究三峡水库运行背景下长江中游水温节律变化对四大家鱼生殖周期的影响，具有重要的科学意义和生态学价值。本研究通过野外调查和室内模拟实验结合，在分子水平、细胞水平和个体水平，研究在三峡水库运行背景下长江中游水温节律改变如何作用于四大家鱼生殖轴（下丘脑-垂体-性腺轴），解析四大家鱼对水温节律改变响应的性腺发育和关键生殖相关激素周期性变化模式。本研究主要结果：1.优化鱼类（鲢等）繁殖相关激素(FSH和LH)ELISA检测技术；2.建立了鲢、鳙等鱼类的下丘脑、垂体、松果体、精巢和卵巢的原代细胞培养方法；3.初步揭示长江鳙、鲢等四大家鱼自然繁殖与水温变化的关系；4.在细胞水平，以鲢松果体、下丘脑、垂体和性腺组织原代细胞培养物为材料，研究生殖轴相关组织细胞对水温的响应特征。在个体水平，以稀有鮈鲫为研究对象，研究水温过程对稀有鮈鲫繁殖影响，初步揭示水温过程对生殖轴影响和繁育相关关键基因的表达模式。5.开展鲢等鱼类的松果体与生殖轴（下丘脑-垂体-性腺轴）相互作用研究，初步揭示温度与褪黑素水平关系和褪黑素作用于生殖轴（下丘脑-垂体-性腺轴）的特性，有助于揭示水温节律变化对四大家鱼性腺发育与繁殖影响。因此，这些研究有助于揭示土著鱼类生殖节律与水温节律的不同步性及其生殖调控机理，进而为四大家鱼等鱼类的人工增殖放流和水库生态调度等提供科学依据。