珠三角养殖池塘水质模型建立及其应用研究

Establishment of Water Quality Model of Farming Ponds in the Pearl River Delta and its Application

以珠江三角洲的基塘式精养池塘为例,经过参数率定、模型验证等工作,建立了地方性精养池塘的水质模型。模型的验证结果表明模型的模拟基本上重现了养殖生产活动过程中生态系统的变化趋势,可以为养殖池塘生态系统的研究和辅助地方的养殖管理工作提供一定的参考。利用建立的养殖池塘的水质模型研究了养殖池塘的水质影响因子和养殖容量的影响因素,研究结果表明:高密度精养池塘氧气的平衡机制已发生了较大的变化,鱼类呼吸已成为耗氧的主要组分,人工增氧的作用已接近甚至超过藻类产氧作用。溶氧浓度易受到各种机制的影响而发生较大的变化。养殖池塘NH4+-N、PO43-的主要来源是鱼类代谢,主要消耗是藻类吸收,二者在水中稳定性好。养殖池塘的养殖容量受到许多因素的影响,内因有饵料的可消化率和可利用率,外因有溶氧水平和NH4+-N的累积等。在精养池塘,随着饵料消化率提高,主养鱼容量迅速增长,最终受制于DO的不足和NH4+-N的累积,套养鱼容量随着主养鱼类的饵料利用率降低而增加,最后受制于DO的不足。如果采用轮放,轮捕的养殖方式,将会更充分的利用养殖空间,进一步扩大养殖容量。

The intensive hike-ponds in the Pearl River Delta are taken to establish a water quality model for pond farming. The results of model verification indicate that the simulation of the model fits the real situation well and it can be used as a research tool for pond aquaculture ecosystem or as a decision support tool for the management of pond farming. The model established is used to research main factors affecting the water quality and the carrying capacity of farming ponds. Results show that DO is generated mainly from phytoplankton photosynthesis and artificial oxygen enhancement, and consumed mainly by fish respiration. DO contents are influenced by various factors. TAN and SRP are generated mainly from fish metabolization and consumed mainly by absorption of phytoplanktons. They change much slowly compared with DO. The farming capacity of the farming ponds is influenced by many factors, including internal factors such as feed digestion and utilization and external factors such as the DO level and the TAN accumulation. The farming capacity of the mainly farmed fish increases with the increase of feed digestion rate and is restricted by the lack of DO and the high TAN concentration. The farming capacity of secondarily farmed fish increases with increasing availability of the heterotrophic feed caused by the decrease of digestion of feed for mainly farmed fish, and is restricted by the lack of DO. Mixed, rotational fishing model makes full exploitation of farming space, which can further extend the farming capacity in fish ponds.