高坝下泄水温度变化对四川裂腹鱼性别分化与种群结构的影响——以雅砻江下游为例

Ecological environment problem caused by water temperature is one of the hot issues in the ecological environment protection of hydro-engineering in China. Effects of water temperature changes under the dam on the growth and reproduction of fish are usually paid more attention, but few attention on sex differentiation and then population structure of fish. JINPING I and ERTAN hydropower stations, two reservoirs with strong regulation performance, have been built in the downstream of Yalong River. Both alone operation and combined operation of these two hydropower stations have great impact on water temperature changes in the downstream of Yalong River. In this project, as one of the major economic fish and threatened fish in the downstream of Yalong River, Schizothorax kozlovi is chosen as a study object. Effects of water temperature change under large dam in the downstream of Yalong River are conducted on sex differentiation and population structure of S. kozlovi. In detail, three methods including culture experiments with controlled temperature, histology and otolith oxygen stable isotope ratio are applied to evaluate the degree of temperature effect from large dam on its sex differentiation and population structure. Then, real-time fluorescent quantitative PCR technique and western blot are adopted to detect the level of mRNA expression and protein expression of several genes of S. kozlovi related with sex differentiation, respectively. In a word, temperature effects on sex differentiation and population structure of S. kozlovi are inquired into from three different levels: molecular level, individual level and population level. Through this study, it will not only provide significantly ecological guidance for the conservation and utilization of S. kozlovi, but also lay the scientific foundation for comprehensively evaluating and mitigating the impact of dam construction on the water ecological environment.

水温导致的生态环境问题是我国水利水电工程生态环境保护中的热点问题之一。关于大坝下泄水温度变化对鱼类的影响,人们通常关注生长和繁殖,而对其性别分化的影响及其可能导致的种群结构变化却少有人关注。雅砻江下游建有锦屏一级和二滩两个调节性能强的水库，其单独和联合运行对水温的影响大。本项目以雅砻江下游主要经济鱼类和受胁鱼类——四川裂腹鱼为对象，从实验室条件和自然条件下开展其性别分化对环境温度的响应研究，采用控温培育、组织学和耳石氧同位素反演方法查明高坝下泄水温度变化对四川裂腹鱼性别分化和种群结构的影响程度，采用实时荧光定量PCR技术和蛋白质免疫印迹试验揭示其性别分化相关基因在转录水平和翻译水平上的温度依赖性表达特征，从分子、个体和种群水平上解析温度对四川裂腹鱼性别分化的影响。本研究可为四川裂腹鱼资源的保护和利用提供重要的生态学指导作用，同时为全面评价和减缓大坝建设对水生态环境造成的影响奠定科学基础。

水温导致的生态环境问题是我国水利水电工程生态环境保护中的热点问题之一。关于大坝下泄水温度变化对鱼类的影响，人们通常关注生长和繁殖，而对其性别分化的影响及其可能导致的种群结构变化却少有人关注。因此，本项目以四川裂腹鱼为研究对象，采用控温培育、组织学、耳石氧同位素反演方法、实时荧光定量PCR技术和蛋白质免疫印迹试验等，揭示了人工培育条件下低温10℃有促进四川裂腹鱼雌性化的趋势，建立了四川裂腹鱼微耳石氧稳定同位素与温度间的线性回归方程，阐明了人工培育条件下温度对四川裂腹鱼耳石形态特征的显著影响作用，揭示了四川裂腹鱼微耳石在不同养殖群体和不同野生群体的碳氧同位素特征，探讨了耳石碳氧同位素在其群体识别中的作用，研究了四川裂腹鱼不同野生群体的性比结构，查明了温度对四川裂腹鱼性别分化相关基因cyp19a、cyp19b、dmrt1、amh、foxl2等在mRNA水平上以及dmrt1在蛋白水平上表达的影响程度，探讨了dmrt1和cyp19a基因mRNA表达的性别差异性与其启动子甲基化间的关系，从分子、个体、种群水平上初步解析了温度对四川裂腹鱼性别分化的影响，可为四川裂腹鱼的资源保护提供重要的生态学指导作用，同时为全面评价大坝建设对水生态环境造成的影响奠定科学基础。