河口区斑节对虾淡化养殖塘水化学状况与水质管理模式

Water quality management modes for Penaeus monodon desalting culture in ponds near estuary and their hydrochemical states

为斑节对虾 (Penaeusmonodon )淡化养殖设计了 3种水质管理模式 (各设 2个水塘 ) :①全封闭式 ,将纳水河水注入池后不再换水 ,仅靠降雨淡化盐度 ;②半封闭式 ,初始水均取自经贮水塘沉淀、曝晒数日的河口水 ,水深为池深的 80 % ,待幼虾全长至 4cm时 ,据水质状况添加河水 ;③逐步加淡水递降盐度方式 ,幼虾长至 4cm时 ,每隔 1～ 2d添加 2～ 5cm河水 ,水满时排出部分水 ,日均降盐度百分比为 0 .2 %～ 1.6 % ,幼虾长至 8～ 10cm时 ,池水最终盐度可降至淡水范围 (S≥ 0 .5 5 )。结果显示 ,3种方法养殖均获成功 ,单产为2 340～ 2 5 5 7kg/hm2 ;方法①塘的成活率最高 ,为 6 6 .4 %～ 6 7.3% ,盐度降率为 12 .3%～ 16 .4 % ,主要离子总量降率为 10 .9%～ 19.0 % ;方法②因只添加少量河水 ,盐度降率仅为 32 .2 %～ 4 8.3% ,主要离子总量降率为 39%～ 6 4% ;方法③的水质类型始终为海水型 (ClNaⅢ) ,盐度降率为 5 2 .8%～ 93.2 % ,主要离子总量降率为5 0 %～ 96 %。各淡化塘全周期有效氮总量较低 ,平均为 0 .2 1～ 0 .5 0mg/L ,其中NH3 Nt含量占 6 6 %以上 ,DO均呈过饱和状态 (10 9%～ 198% ) ,pH与COD较高 ,分别为 8.79～ 9.2 5与 16 .5 5～ 2 4 .2 1mg/L。

Three water quality management modes were designed for Penaeus monodon desalting culture in the ponds near estuarine area, each mode with 2 ponds. The modes are: ①completely closed mode; ②semi closed mode; ③the mode with fresh water added gradually for gradient decrease of salinity, i.e. river water is added by 2～5 cm of depth in the intervals of 1～2 d, and when the water is full, drain some water away. The daily salinity decrease percentage maintains at 0.2%～1.6% and when the juvenile body length gets to 8～10 cm, the salinity of the pond water can decrease to the range of freshwater (S≥0.55). The results show that the 3 modes all gets succeeded with the production of 2 340～2 557kg/hm 2; mode ① has the highest survival rate (67.3%) and the decrease rates of salinity and total main ion contents are 12.3%～16.4% and 10.9%～ 19.0% , respectively; mode ② has the decrease rates of salinity and total main ion contents of 32.2%～48.3% and 50%～96%, respectively; mode ③ maintains the sea water character (Cl Na Ⅲ) all the cycle and the decrease rates of salinity and total main ion contents are 52.8%～93.2% and 50%～96%, respectively. In all the 3 mode ponds and during the culture cycle, the total effective nitrogen has a low level, averaged 0.21～0.50 mg/L, among which NH 3-Nt occupies over 66%, and DO shows over saturation(109%～198%), but pH and COD Mn maintain high at 8.79～9.25 and 16.55～24.21 mg/L, respectively.