CSA Xpert

Female brood stock is usually obtained from grow-out ponds or from capture fisheries. Normally, "berried" or egg-carrying females are used only once.

Fertilization: A typical male to female ratio is maintained in brood stock holding systems. Within a few hours of copulation, external fertilization occurs and the eggs are transferred to the brood chamber beneath the abdomen of the female. Eggs are orange until 2-3 days before hatching and just before hatching, they become grey-black. The eggs remain attached to the female during embryonic development. At hatching, free-swimming zoeae are produced.

Larval development: First stage zoeae are very small in size about 2mm and grow through 11 larval stages, to almost 8 mm at metamorphosis into post larval forms. Individual metamorphosis can be achieved in 16 days but usually takes much longer, depending on environmental conditions.

Larval feeding: Various feed items viz., Artemianauplii, zooplankton especially cladocerans, copepods, rotifers, flesh of prawn and fish, molluscan meat, earthworms, tubificidworm, egg custard and cut pieces of goat/hen viscera are used during larval rearing. Among these Artemianauplii have been recognized as an excellent larval food for the prawn larvae. At the beginning, freshly hatched Artemianauplii are provided to the 1st stage zoea at 1 g/30,000 larvae twice daily up to 15 days or till they attain stage VI. Thereafter, the feed is given once daily along with egg custard and mussel meat/tubificid worm four times daily.

Feed and feeding: Feed managements are very crucial, and natural food is preferred over supplementary food. Supplementary food includes agricultural and animal husbandry by-products along with locally available cheap feeds like broken rice, tapioca root, trash fish, vegetable and animal feeds mixed in adequate proportions. The feed is produced in pellet form, and are distributed uniformly on the surface of the pond or placed in wide containers set up at several points along the margin of the pond. The rate of feeding depends on the age of the prawns.

Grow-out culture: Grow-out system of prawn is normally having pond embankment 0.5 m higher from the water level. Sandy-clay pond bottom is considered to be favorable for better growth. Undrainable ponds may be treated with conventional pesticides for eradication of predatory and weed fishes. Stocking density of 30,000 to 50,000/ha is recommended for semi intensive monoculture farming. Ponds with the facility of water exchange and aeration can be used for intensive farming where stocking density could be increased to 1 lakh/ha. Temperature is the most important factor which directly controls the growth and survival of prawns. Temperatures above 35°C or below 14°C are generally reported to be lethal and 29-31°C is optimal. Male prawns grow faster than females. Mixture of groundnut oil cake and fish meal in the proportion 1:1 is used as supplementary feed. A production of 750-1200 kg/ha in six months of rearing are achieved under monoculture with the stocking density of 30,000-50,000. In polyculture, M. malcolmsoniiat a stocking density of10,000-20,000/ha along with carps at density of 2,500-3,500 nos/ha, a production of 300-400 kg prawn and 2000-3000 kg carps can also be raised.