6 Grow-out phase
FRESHWATER PRAWNS may be stocked into concrete and earthen reservoirs, ponds, irrigation ditches, cages, pens and natural waters. Cage and pen culture is experimental, while the production from irrigation ditches is low. Stocking natural waters and reservoirs is called fisheries enhancement. Freshwater prawns are obtained from rivers, or (less frequently) from nurseries, for stocking into open waters.
Stocking PL is impractical because most would be lost through predation. Larger juveniles (2-3 g) are usually used for enhancement purposes. The topic of fisheries enhancement is only mentioned here but is described in more detail in New, Singholka and Kutty (2000). This section of the manual deals only with the management of freshwater prawns being reared in earthen ponds.
A freshwater prawn farm is very similar to a freshwater fish farm. A detailed farm design is not provided in this manual because every farm must be unique to its site characteristics.
A photograph of a large freshwater prawn farm is given in Figure 43. This section of the manual briefly introduces some general principles of aquafarm development. In doing so, it draws upon some other FAO manuals on site surveying (FAO 1989b), the provision of water supplies (FAO 1981), and farm and pond construction (FAO 1992b, 1995).
A simple manual on small-scale freshwater fish farming (FAO 1994) is also available. If you are going to build your own farm, it is highly recommended that you obtain these publications before you develop your farm.