凡纳滨对虾海水高位池养殖水体理化因子变化与营养状况分析

Analysis of Physical-chemical Factors Variation and Nutritional Status of Litopenaeus vannamei High Level Seawater Ponds

2008年4月至8月,在广东汕尾红海湾对虾海水高位池高密度养殖基地对养殖全程池塘水体进行周期性连续采样测试。结果显示,养殖过程水温、盐度和溶解氧波动较大,pH值从8.95~9.37下降至7.21~7.27,透明度从38~78 cm下降至20 cm;COD在养殖前中期即达到较高的水平,在10 mg.L-1左右波动;氨氮和亚硝氮在养殖中期积累增加,养殖后期急剧上升。养殖水体营养状况经历了贫营养-磷限制中度营养-氮限制潜在性富营养-磷中等限制潜在性富营养-磷限制潜在性富营养的变化,活性磷酸盐先于无机氮在养殖中期积累增加,但无机氮在养殖后期积累更加快速。结果表明,水质因子的波动和水体营养的不平衡明显影响对虾的健康生长,养殖过程要加强环境营养调控和微生物调控手段,养殖前期适当提高水体营养水平,养殖中后期强化代谢产物降解转化,减轻富营养化程度,同时要密切监控和及时调控溶解氧、pH值、氨氮和亚硝氮的变化,营造有利于对虾健康生长的良好水环境。

Investigations were conducted on water quality in high-density seawater shrimp（Litopenaeus vannamai）culture ponds in Honghai bay,Shanwei,Guangdong Province,China from April to August in 2008.The results showed that water temperature,salinity and DO fluctuat-ed greatly during the process of culture,pH decreased from 8.95~9.37 to 7.21~7.27,and transparency decreased from 38~78 cm to 20 cm,COD reached around 10 mg.L-1 in early and middle period,ammonia nitrogen and nitrite nitrogen increased from the middle period,and rised quickly in the last period.During the whole process of culture,the nutritional status of aquaculture water experienced the following changes： poor trophic-medium trophic with limited phosphorus-potential eutrophic with limited nitrogen-potential eutrophic with medium limited phosphorus-potential eutrophic with limited phosphorus.In the middle period,phosphate accumulated prior to the inorganic nitrogen,while the latter accumulated rapidly in the later period.The results demonstrated that the healthy growth of shrimp was affected significantly by fluctuations of water quality parameters and nutritional imbalance.Therefore,environment nutrition regulation and microbial control measures should be strengthened during the whole culture process.In the early period water nutrition levels should be improved properly,and metabo-lites degradation should be enhanced in the middle and later periods to reduce eutrophication.At the same time,to create a well water envi-ronment for healthy growth of shrimp,the changes of DO,pH,ammonia nitrogen and nitrite nitrogen should be monitored closely and regulat-ed timely.