Coastal Aquaculture and Mariculture (2+1)

Unit 6 - Culture of Crustaceans

6.1.7. Aeration and Harvesting
Aeration

Aeration is necessary in semi-intensive culture. Aeration is carried out using 10-12 1HP paddle wheel aerators per hectare. The aerators are switched on when the dissolved oxygen content falls below 4 mg/L. This happens usually during the night time when oxygen is not supplied by the photosynthesis by phytoplankton. Sometimes aeration is also carried out in the afternoons to break the thermal stratification in the ponds which could hinder penetration of oxygen from the air.

Harvesting

The shrimp are harvested when they reach marketable size of 20-40g in 3-5 months. A bag net is fitted to the outlet and water is let out during low tide. Shrimps are carried by the out-flowing water which gets collected in the net fixed to the outlet. Shrimps are periodically collected from the net, washed with clean estuarine water, ice-chilled and sold to the processors.