珠三角地区密养淡水鱼塘水体叶绿素a及水环境动态研究

于2012年5月—12月调查了珠三角地区主养笋壳鱼(Oxyeleotris marmoratus)、草鱼(Ctenopharyngodon idellus)、加州鲈(Micropterus salmoides)和乌鳢(Channa argus)四个品种池塘水体中的叶绿素a(Chl a)含量和水环境因子动态变化。通过方差分析和多重比较方法研究池塘间水质因子的差异,使用逐步回归方法分析池塘中Chl a含量变化的影响因子,使用自组织神经网络(SOM)分析方法探讨池塘水质状况。研究结果显示:池塘水体TN、TP和化学耗氧量(Chemical Oxygen Demand,CODMn)变化范围分别为1.52~22.76 mg/L、0.20~4.82 mg/L和3.71~50.76 mg/L,呈现出严重富营养化和有机污染状况;池塘间Chl a含量差异显著(P0.05),从高到低顺序为:草鱼(均值)乌鳢加州鲈笋壳鱼,各池塘Chl a含量的影响因子差异较大;乌鳢池塘中盐度(Sal)、电导率(Cond)、总可溶性固体(TDS)、TP、PO43--P、TN、NO3--N和CODMn等因子显著高于其他品种(P0.05);整个采样期池塘水质状况可分为5大类,并呈现出一定的时序和空间特征,池塘水质优劣顺序为笋壳鱼加州鲈草鱼乌鳢。

Studies on Dynamics of Chl a and Water Environment of Intensive Fishponds in Pearl River Delta

Investigation on dynamics of Chl a concentration and water environment of four intensive fishponds, which cultured Oxyeleotris marmoratus, Ctenopharyngodon idellus, Micropterus salmoides and Channa argus, were carried out between May 2012 and December 2012 in Pearl River Delta. Variance analysis and Multiple Comparison (LSD) were used to study the difference of the water parameters of the fishponds, and stepwise multiple regression was used to analyze the relationships between Chl a and environmental factors in the investigating ponds, while the Self-Organizing Map (SOM) analysis was used to explore the water quality conditions. Results showed that TN, TP and Chemical Oxygen Demand (COD_Mn) of the ponds were varied from 1.52~22.76 mg/L, 0.20~4.82 mg/L and 3.71~50.76 mg/L, respectively, which indicated the water were overloaded by nutrients and organic contamination. There was significant difference on Chl a concentration (P<0.05) among the four kinds of fish ponds. Ctenopharyngodon idellus ponds had the highest Chl a concentration (mean value), followed by the Channa argus ponds and the Micropterus salmoides ponds, and the lowest was Oxyeleotris marmoratus ponds. Besides, the relationships between Chl a and environmental factors were different in each sampling ponds. Water environment parameters, such as salinity, conductivity, Total Dissolved Solids (TDS), COD_Mn, TN, TP, NO₃^--N, PO₄^3--P in Channa argus ponds were obviously higher (P<0.05) than other kinds. Based on SOM analysis, five clustering groups on water quality of all sampled ponds were found according to spatio-temporal patterns, and the water environment quality changed worse from Oxyeleotris marmoratus, Micropterus salmoides, Ctenopharyngodon idellus to Channa argus ponds.