作为外来种，银鱼的大规模引种导致了云南主要湖泊土著鱼类生物多样性的下降和生态系统结构与功能的变化。对湖泊的有效保护迫切需要加强银鱼的生态学研究，认识其营养循环作用对高原湖泊生态系统功能的影响。本项目拟以云南典型湖泊中的太湖新银鱼为研究对象，通过分析银鱼的碳、氮、磷元素组成，了解其在个体发育和种内变化方面的特征，认识银鱼体内元素计量学变化的主要影响因素，揭示它在营养元素需求上对高原湖泊环境的适应性特征；利用中宇宙实验，明确银鱼是否受严格内稳态控制；通过营养排泄实验，掌握银鱼的营养排泄特点，并结合银鱼种群数量评估其对水体营养盐的贡献；利用原位实验，揭示银鱼亲体尸体的分解过程，获得其对水体营养盐的贡献。本项目预期将丰富我国鱼类引种生态学效应方面的基础数据，为高原湖泊的生态环境保护和渔业管理提供基础数据与理论依据。

The large-scale introduction of Neosalanx taihuensis, a non-native species, has caused the decline in the biodiversity of native fishes and changes in ecosystem structure and function in main Yunnan Plateau lakes.Based on the fact that icefish has dominated the fish community in many plateau lakes, it is urgent to understand its adaption and ecological effects in these waters. The present study will be conducted to quantify ontogenetic and intraspecific variations in stoichiometry in N. taihuensis by analyzing its carbon(C), nitrogen(N) and phosphorus(P) content.According to its nutrient demand, the adaption mechanism of icefish in the plateau lakes will be explored.Whether icefish maintains strict homeostasis in nutrient compostion or not will be examined through a mesocosm experiment. To understand how the excretion rate and ratio of icefish varies with body mass, nutrient content of food resources and temperature, excretion experiments will be performed via measurements of ammonia nitrogen (NH3-N) and soluble reactive phosphorus(SRP) excreted by N. taihuensis on the spot. The amount of nutrients recycled by icefish population in the lakes will be calculated by multiplying its excretion rate and biomass.In addition, we will conduct in situ experiments to examine the decomposition process of carcasses of icefish's parents.According to the amount of nutrients lost from the carcasses, the contribution of the carcasses to the nutrients in water column will be obtained.The present study will help to understand the ecological effects of icefish in Yunnan Plateau lakes and provide scientific evidences for ecosystem-based fisheries management.