Coastal Aquaculture and Mariculture (2+1)

Unit 6 - Culture of Crustaceans

6.1.6. Water quality management

Health and growth of shrimps depends on water quality. Hence water quality should be maintained at optimum levels. The water quality can be maintained by proper water exchange, aeration and addition of chemicals such as lime, zeolite, dolomite etc.

Water should be exchanged when water quality parameters go beyond optimum levels. Required quantity of water should be let out from the pond and it should be replaced with fresh brackish water. The rate of water exchange depends on the density of shrimps in the pond and feeding rate. Higher the density, more the feed applied to the pond, hence higher the rate of water exchange. During the first month it may not be necessary to exchange water. In modified extensive pond water is exchanged every neap and spring tide. One third of the water is let out every day and replaced with fresh brackish water each day for three consecutive days. In semi-intensive culture there is a progressive increase in the rate of water exchange over the culture period. The rate of exchange initially may be 5% per day increasing to 30% per day during the end of the culture period. The amount of water to be exchanged should be judged by the water quality parameters. Therefore, regular monitoring of the water quality would be required.