珠江三角洲基塘水产养殖对水环境的影响

Effects of Fish Aquaculture on Water Environment in the Zhujiang River Delta

为了解珠江三角洲基塘水产养殖对水环境的影响,选择4个典型基塘进行了一个养殖周期的跟踪调查-、COD、Chla等指标均有明显的升+、NO2并进行养殖池塘的营养物质平衡概算。结果表明:养殖池塘中的NH4高,而NO-3、TP、SRP、BOD等指标无明显升高,DO没有明显下降。密养池塘无机氮的组成发生了明显的变化:NH+4的主要影响因子是养殖密度和3比例下降,降到40%以下。养殖池塘NH+4比例上升,占了50%以上,NO-藻类浓度。P是养殖池塘浮游植物生长的限制性因子。塘泥的吸附和释放可能是影响池塘TP、SRP的主要因素。营养物质平衡计算结果表明,研究池塘中营养物质N的输入饲料占90%～98%,N的输出鱼类仅占总输出的20%～27%,沉积的N占54%～77%。营养物质P的输入饲料占97%～98%,鱼类P仅占总输出的8%～24%,沉积的P占72%～89%。珠江三角洲的养殖池塘由于其封闭性,养殖产生的废物不易外排,只能依靠池塘的自净作用消解废物。

An investigation was carried out for several aquaculture ponds in the Zhujiang River Delta for a culturing period to determine the effects of dense aquaculture on water quality and nutrient budget. NH^+-4,NO^--2,COD and Chla increased remarkedly during the study period, while NO^--3,TP,SRP,BOD and DO remained as those of the contrast points, the components of inorganic nitrogen changed in aquaculture pond, with NH^+-4 increased and NO^--3 decreased remarkedly. Nutrient budget revealed that fish could only assimilate 20%～27% nitrogen and 8%～24% phosphorus of the total inputs. The major source of nutrient input was feed, fish feed accounted for 90%～98% nitrogen and 97%～98% phosphorus of the total inputs. The major nutrients sank into the sediment, which accounted for 54%～77% nitrogen and 72%～89% phosphorus of the total inputs. The study also revealed that fish excretion, phytoplankton and sediments were the main factors which exert influence on water quality in aquaculture ponds.