The Indian prawn (Fenneropenaeus indicus, formerly Penaeus indicus), is one of the major commercial prawn species of the world.
Supply of seeds[edit]
Seeds can be obtained from the wild or by establishment of hatcheries. In traditional paddy field systems the juveniles which have congregated near the sluice gates are allowed to enter the field with the incoming high tide. Among the prawn species entering the field F. indicus constitute around 36%–43%.[9] Earlier wild seeds were also collected and sold to shrimp farmers. Nowadays the dependence on wild seed has been reduced due to establishment of hatcheries and also due to reduction in wild seeds due to overfishing.
Broodstock[edit]
Intensification of cultured shrimp is limited by seed supply. The production of seeds in hatcheries depends on the availability of broodstock and quality of spawners. Spawners for seed production can be obtained from the wild or can be developed by induced maturation in hatcheries.
Matured individuals can be collected from the wild during their peak spawning seasons in March/April and July/August in the tropics.[10] A temperature range of 27–31 °C (81–88 °F) and salinity of 30‰–35‰ is ideal for spawning.[6]
Although hatcheries in the developing countries still depend on wild seed, maturation can be induced by eyestalk ablation technique where eyestalks of females are unilaterally ablated to stimulate endocrine activity. The ablated females spawn after 4 days, with a peak observed at days 5–6.[11] However it is expensive to raise spawners in captivity and ablated shrimps result in less hardy fry with low survival rate.[12] Even though the fecundity of the ablated females may not differ significantly,[11][13] the hatch rates of ablated females was found to be markedly less (37.8% to 58.1%) than that of unablated females (69.2%).[11] It is also found that wild females are more fecund per unit weight than ablated females.[13] However quantitatively the number of spawns, eggs and nauplii produced by ablated females is ten, eight and six times respectively that of unablated females.[6]