模拟阴天对南美白对虾养殖水体理化及其生长指标的影响

THE EFFECT OF SIMULATING THE CLOUDY DAY ON AQUACULTURE WATER PHYSIOCHEMICAL CHARACTERS AND GROWTH INDEX OF PENAEUS VANNAMEI

为探索阴天对南美白对虾(Penaeus vannamei Boon)养殖水体理化及其生长指标的影响,实验采用黑色遮荫网模拟阴天弱光环境对南美白对虾进行遮荫实验,设置遮荫组与对照组各5个平行,实验周期7周。遮荫组采用黑色遮荫网交替性遮荫,即第1、第3、第5、第7周遮荫,第2、第4、第6周曝光,对照组正常养殖。结果显示:遮荫组与对照组的p H、DO、Chl.a、NH_4^+-N、NH_3-N、NO_2^--N、NO_3^--N及PO_4^(3-)-P的浓度在遮荫处理下具有显著性差异(P<0.05),Chl.a、NH_4^+-N及PO_4^(3-)-P的浓度具有明显的波动性,表现为遮荫时Chl.a的浓度极显著降低(P<0.01),NH_4^+-N、PO_4^(3-)-P的浓度极显著升高(P<0.01);曝光时遮荫组Chl.a的浓度较遮荫时升高,NH_4^+-N的浓度极显著降低(P<0.01),PO_4^(3-)-P浓度的增长幅度降低,此时遮荫组与对照组Chl.a、NH_4^+-N及PO_4^(3-)-P的浓度无显著差异。NO_2^--N的浓度在实验前5周,遮荫组高于对照组,第6、7周对照组高于遮荫组。NO_3^--N浓度在整个实验周期中则是遮荫组高于对照组。南美白对虾生长指标结果显示:两个组生长指标具有显著性差异。研究表明:妨害南美白对虾生长的主要是NH_3-N,然后是NO_2^--N;藻类可间接促进南美白对虾生长。遮荫处理抑制藻类吸收养殖水体中的有毒离子、恶化南美白对虾的生长环境并危害对虾的生存、生长。

To explore effects of cloudy day on growth index of Penaeus vannamei and physiochemical characters ofaquaculture water, the low light environment in cloudy day was simulated by adding black shade net to P. vannamei inthe 1^st, 3^rd, 5^th, and 7^th week of the 7-week trial. The control group was exposed to daylight in the whole experimentalperiod. The results revealed significant differences on pH, DO, Chl. a, NH4^＋-N, NH3-N, NO2^--N, NO3^--N, PO4^3- -Pbetween the shade group and the control group （P〈0.05）. Cloudy day simulation significantly reduced Chl. a level butsignificantly increased the concentration of NH4^＋ -N and PO4^3--P （P〈0.01）. Cloudy day simulation showed no signifi-cant change in the concentration of Chl. a, NH4^＋ -N and PO4^3- -P. Cloudy day simulation increased concentration of NO2^--N in the first 5 weeks, which was reversed at the 6^th and 7^th week. Cloudy day simulation also enhanced NO3^--Nconcentration for the whole time. These results suggest that NH3-N and NO2^--N may inhibit the growth of P. vannamei.The algae could indirectly benefit the growth of P. vannamei. Cloudy day simulation inhibited algae from absorbing the