白洋淀两种养殖系统的水质及能值分析-水生生物学专业论文.docx

摘要
摘 要
作为华北地区最大的浅水淡水湖泊,白洋淀日益严重的富营养化问题逐渐引起人们尤其是管理者的重视。水产养殖是影响水体环境的重要因子,因此本研究通过查询资料和现场调研,分析了白洋淀两种水产养殖结构和养殖方式对其周围水环境的影响。在此基础上,根据食物链理论在白洋淀小西淀建立了生态养殖系统,并与杜家淀普通养殖模式进行对比,利用能值分析方法揭示两养殖系统的能值转化差异,评估资源利用效率及其环境效应,从而为白洋淀生态系统系统的恢复与维持提供依据。主要研究结果如下: 1 白洋淀水产养殖品种以草鱼、鲤、鲢、鳙为主,约占养殖总量的 80~95%;中华绒螯蟹养殖产量约占养殖总量的 2~3%左右;日本沼虾、黄颡鱼、乌鳢、鳜鱼等名优品种养殖产量只占养殖总量的 2%左右。水产养殖模式有围网、栏网、网箱(合称三网)、围堤、池塘、沟壕六种方式,其中以三网养殖规模最大。养殖区水体环境沉水植物消失,
水质呈现富营养化状态,底泥厚度增大。养殖结构单一、养殖密度过大和盲目投饵是影响养殖水体环境的重要因子。
2 在白洋淀小西淀建立了生态养殖系统。系统中包含穗花狐尾藻和菱为主的水生植物,投放鲢、鳙等滤食性鱼类,并配以中华绒螯蟹和日本沼虾。研究结果显示,与普通养殖模式的杜家淀养殖系统相比,小西淀养殖系统水体透明度明显高于杜家淀,总氮、总磷、叶绿素 a 含量和营养状态指数低于杜家淀,说明生态养殖系统对水质有明显的改善作用。
3 两个养殖系统能值分析结果显示,小西淀生态养殖系统能量转化效率高,单位面积的能值产出和经济收入均优于杜家淀。杜家淀产出率高,环境负载率低,因而可持续性较高,原因是小西淀对系统投入的不可更新能源过多所致。因此,对小西淀养殖模式管理应进一步调整和优化,在经济效益与可持续性之间找到一个稳定平衡点。
关键词 白洋淀 水产养殖模式 能值分析 环境效益
Abstract
Abstract
As the largest freshwater lake in the North China, the growing eutrophication of Baiyangdian lake has been paid attention by more and more people, especially the managers. The past studies showed that aquaculture was an important factor. Based on survey of aquacultural model in Baiyangdian lake, this paper mainly focuses on the application of ecological restoration by submerged plant and food chain in Xiaoxidian. Emergy synthesis method has created new method to do quantitative research with eco-economic system. In order to improve water quality and get better benefits. This pared two eco-economic systems of different aquacultural models using emergy synthesis method. Transformation efficiency and sustainability were estimated in two aquacultural systems, aiming .to provide data for managers and users.
Baiyangdian aquaculture species mainly included Ctenopharynodon idellus, Cyprinus carpio, Hypophthalmichthys molitrix and Aristichthys nobilis which account for about 80% to 95% of total area. The production of Chinese mitten crab aquaculture accounts for about 2% to 3%. Other aquatic production accounts for only about 2%, such as Macrobrachium nipponense, Pelteobagrus fulvidrac