青海高原冷水鱼养殖网箱附着藻类防控原理与方法研究

Qinghai Province, whose coldwater fish industry has been developing rapidly these years, has become the biggest coldwater fish cage culture base in China, due to its abundance in cold water resources. However, the discharge of nutrient by cage aquaculture stimulates the growth of the periphyton which has already been accustomed to the low-nutrient environment condition in lakes and reservoirs in Qinghai Province. These periphyton cells attach to the net and show great impacts on the coldwater fish cage culture. To solve this problem, the reasons for the rapid growth of the periphyton and the attachment process and growth characterization of the periphyton are studied. The prevention and control principles and methods of periphyton in lakes and reservoirs in Qinghai Province are put forward based on the further analysis of the biology and ecology of the periphyton, the major environment factors, the properties of cage nets and anti-fouling coating in this research program. This research will provide vital references for the prevention and control of the mass growth of periphyton in lakes and reservoirs in Qinghai Plateau, as well as technical support for the sustainable development of coldwater fish industry in Northwest China.

青海省冷水资源丰富，冷水鱼产业发展迅猛，已经成为全国最大的冷水鱼网箱养殖基地。网箱养殖排放的营养盐刺激了原本适应贫营养环境的藻类的生长。大量藻类附着在养殖网箱上，对青海省冷水鱼网箱养殖造成较大的影响。针对这一问题，本项目研究了附着藻类的附着过程和生长规律，分析了青海高原冷水鱼养殖网箱附着藻类大量生长的原因，并从附着藻类的生物学特征和生态学规律、主要水环境因子的影响、养殖网片性质和防附着涂料等方面提出了青海高原冷水鱼养殖网箱附着藻类的防控原理与方法。本研究将为青海高原冷水鱼养殖网箱附着藻类的防控提供参考，为我国西北地区冷水鱼产业的可持续发展提供技术支持。

青海省冷水鱼养殖产业发展迅猛，已成为全国最重要的鲑鳟鱼网箱养殖基地。网箱养殖过程中大量藻类易附着在网箱网衣表面，成为养殖生产过程中面临的难题。研究发现青海省冷水养殖区域的附着藻类的优势种主要为水绵（Spirogyra）。群落种类、数量组成以硅藻门和绿藻门为主。附着藻类生物量呈现春夏多，秋冬少的分布趋势；在垂直方向上主要分布于水体表层0-3米处。其附着过程与其他淡水水域附着过程相似，呈现有机物-微型硅藻-较大硅藻-绿藻-丝状绿藻的附着过程，但在具体物种上存在差别，体现了高原冷水性湖泊附着藻类的组成特点。水环境因子对附着藻类的生长具有重要的意义，温度、光照强度、水体扰动速率、营养盐浓度、附着基底是附着藻类生长的重要影响因子。附着藻类生长随温度和光照的增加呈现先促进后抑制的趋势；在一定范围内，营养盐浓度和藻类的生长呈正相关，当浓度过高时会抑制藻类的生长；水体扰动对藻类的影响整体呈现低促高抑现象；当附着藻类存在附着基底时，其生长状况明显优于漂浮状态。网衣性质、附着基底材料、防污涂料和光电催化纳米材料等对附着藻类的防治效果研究结果显示，附着藻类对网孔直径、网片股数、附着基底颜色以及网衣材质具有一定的趋好性；光滑的表面藻类附着要难于粗糙的表面；涂覆防污涂料对藻类附着有明显的影响，进而提出拼接网衣法、网衣围裙法、光电催化法等适用于黄河上游养殖网箱附着藻类防控的防控模式。本研究将为青海地区冷水鱼养殖网箱附着藻类的防控提供技术支持。