中华鳖不同生态养殖模式对池塘水环境及养殖效果的影响

利用条件相近的两组池塘,对中华鳖(Trionyx sinensis)的两种生态模式(Ⅰ组:中华鳖-吃食性鱼类鲤和草鱼模式;Ⅱ组:中华鳖-杂食性水生动物鲫和螺模式)对池塘水环境以及养殖效果的影响进行对比试验。结果表明,Ⅱ组CODMn在7、8、和9月显著低于Ⅰ组(P<0.05),NH3在6、7、8和9月显著低于Ⅰ组(P<0.05),TP在7月和8月显著低于Ⅰ组(P<0.05),TN在6、7和8月显著低于Ⅰ组(P<0.05),NO2--N在6月和7月显著低于Ⅰ组(P<0.05),Ⅱ组水环境质量较Ⅰ组好。Ⅱ组检出藻类47种,Ⅰ组34种,Ⅱ组种类显著增多(P<0.05);Ⅰ组蓝藻重量占83.18%,硅藻2.98%,隐藻2.65%,甲藻0%,Ⅱ组蓝藻58.59%,硅藻13.44%,隐藻14.00%,甲藻7.07%,Ⅱ组蓝藻明显下降,而硅藻、隐藻、甲藻明显上升(P<0.05)。6月Ⅰ组平均生物量4.18mg/L,Ⅱ组2.57mg/L,8月Ⅰ组29.04mg/L,Ⅱ组5.41mg/L,6月和8月Ⅰ组生物量均显著高于Ⅱ组(P<0.05)。Ⅰ组Shannon-Wiener指数H’在6月和8月均值分别为2.117和0.7467,Ⅱ组均值分别为2.5427和1.0178,Ⅱ组6月和8月H’均明显增加(P<0.05);在6月,Ⅱ组Margalef丰富度指数d为1.8516,Ⅰ组为1.2499,Ⅱ组较Ⅰ组上升明显(P<0.05);两组的Pielou匀度均指数J差别不大。Ⅱ组中华鳖平均产量11782.5kg/hm2,显著高于Ⅰ组11482.5kg/hm2(P<0.05)。

Effects of Different Culturing Modes on Pond Environment and Output of Trionyx sinensis

The effects of two ecological modes(group I:Trionyx sinensis and predatory fishes-cyprinoid and grass carp;group II:Trionyx sinensis and omnivore aquatic animals-crucian and conch) on pond environment and output of Trionyx sinensis was studied under two pond groups with similar environment.In terms of the physical-chemical factors of water quality,CODMn in group II was significantly lower than that in group I from July to September(P <0.05) ;NH3 was significantly lower than that in group I from June to September(P <0.05) ;TP was significantly lower than that in group I in July and August(P < 0.01) ;TN was significantly lower than that in group I from June to August(P < 0.05) ;NO2--N was significantly lower than that in group I in June and July(P < 0.05).Phytoplankton community increased significantly in group II with 47 algae,while 34 algae in group I.The weight of Cyanophyta,Bacillariophyceae,Cryptophyta and Pyrrophyta in group I accounted for 83.18%,2.98%,2.65% and 0%,respectively;while it was 58.59%,13.44%,14.00% and 7.07% in group II,respectively,with Cyanophyta decreasing significantly and the other three algae increasing significantly(P < 0.05).The average biomass was 4.18 mg /L in group I while 2.57 mg /L in group II in June,and it was 29.04 mg /L in group I while 5.41 mg /L in group II in August.The biomass was higher in group I than that in group II in both months(P <0.05).In terms of biodiversity index,the Shannon-Wiener index was 2.117 and 0.7467 in group I in June and August,while it increased significantly to 2.5427 and 1.0178 separately in group II in both months(P <0.05).The Margalef richness index was 1.8516 in group I and 1.2499 in group II.It increased significantly in group II than that in group I(P < 0.05).The Pielou evenness index showed little change.The average output of Trionyx sinensis in group II was 11782.5 kg /hm2,which was significantly higher than that in group I with 11482.5 kg(P < 0.05).