Vannamei Dilute Aquaculture Water Quality Law

The effect of different desalting culture water type on survival and growth of Litopenaeus vannamei , the change regulation of water quality and the effect of typhoon on water quality in desalting culture shrimp pond were conducted. The main results were as followed:1. Survival rates of L. vanname (in water type of C_I^Na,Cl_II^Na,C_II^Ca,Cl_II^Na were 0,45-70%,60-70% and 80%, respectively, and the highest survival rate was occurred in water type of Cl_III^Na .2. Main ion contents in test ponds were decreased with the different desalting water type during the duration of desalting pond culture of L. vannamei, and decreased percentage of ion total content was 24.0% in closed desalting culture pond, 52.1% in semi-closed desalting culture pond, while 67.5% was occurred in type of fresh water adding salt. Desalting culture pattern and water supplies affected the ion relations of different desalting culture pond.3. Transparency of desalting culture pond was lower during the culture period. COD_Mn,NH₃-N_t, and NO₂^--N increased slowly, while DO,pH increased firstly then decreased at the end of culture period, the daily variation of DO was also obviously.4. The effect of the compound microbiological preparations on water quality of No. 1 pond was obviously. NH₃-N_t and COD_Mn,, decreased 46.8% and 12.8%, respectively at 7th. After 15th, NO₂^--N decreased 35.2%, while NH₃-N_t and COD_Mn increased slightly. So compound microbiological preparations should be poured into desalting culture shrimp pond every 15d.5. Water quality factors such as temperature, pH, Do, and salinity decreased, whileNH₃-N_t and NO₂^--N increased around typhoon. Fertilization before typhoon could keep transparency of desalting culture pond and stability of water quality.