SOME PHYSICO-CHEMICAL CHARACTERISTICS OF KAKDWIP BRACKISHWATER PONDS AND THEIR INFLUENCE ON THE SURVIVAL, GROWTH AND PRODUCTION OF PENAEUS MONODON (FABRICIUS)

Influence of soil and water characteristics on the culture of Penaeus monodon (Fabricius) as found in some experimental farms in Kakdwip, W. Bengal, is described based on the findings on 28 crops during a period from 1979 to 1982. Salinity and temperature in the water phase and organic carbon, available phosphorus and available nitrogen in the soil phase showed distinct relationship with P. monodon production. Steadily changing temperature (both decreasing and increasing) and increasing phase of salinity, during October to June, were found to be best. But abrupt fluctuations of salinity and temperature and presence of predators were detrimental, as was the case during July to October. Dissolved oxygen below 2.5 ppm affected the survival of the prawns. Depth, turbidity, pH, total alkalinity and primary productivity showed no direct relationship with production. P. monodon production was more than 200 kg|ha|crop when the available nitrogen and available phosphate in the soil phase were more than 12.30 and 1.32 mgllOO g soil and when organic carbon was more than 1.02%.