This is an environment friendly (sustainable)intensive as well as semi-intensive sweet water tiger prawn farming setup. We literally pump water from under the ground at a salinity of 2.5 ppt to fill the ponds. We then add the required salt, minerals and nutrients and increase the salinity to 5 plus ppt. The baby prawns flown in, or by road, from cox's bazar at 10 ppt salinity are acclimatised to t
he 5 ppt pond water. Under these conditions the baby prawns are nurtured in the nursery pond for about a month till body wt of 2 gms or so. The mortality rate in the nursery pond is around 20%. After 30 days they are transferred to the pre-prepared grow out ponds. They spend about 120 to 150 days here - based on the growth rate and the market demand/supply scenario. During the grow out phase the ponds are constantly replenished with the consumed salt, minerals and nutrients. For harvest the ponds are half emptied first followed by netting - 2 to 3 times the full length of the pond. The rest of the water is then drain out completely to complete the harvest. For the first time, in Bangladesh, we are draining the ponds into specially prepared recycling ponds. Here the water is treated with required amount of alum and potassium permanganate. Once the water is purified and the sediments settled the water is transferred to the nursery and grow out ponds. This procedure helps keep the area pollution to zero as well as helps minimise on the cost of the salt, minerals and nutrients needed for the next production cycle, which would, otherwise have been poured out into the surrounding fields with no use rather damage the environment in the long run.
