Broodstock development and spawning in Penaeus indicus

Abstract

Among cultivable native species, Penaeus indicus occupies an inyjortant position due to its tolerance to wide range of salinity, fast growtK compatibilitij in high density culture, wide distribution and demand in export market. P. indicus broodstock can be developed using adults collected from the wild or from grow out ponds or by reusing healthy females after spawning in the hatchery. The size of prawn used for broodstock development should preferably be above 145 mmT.L. (20 g) for females and 140 mm T.L. (17 g)for males. Pens, cages, tanks with or withoutjlow through system, recirculation system etc. are in vogue for broodstock development. 1001 tanks with in situ biological filter is used for the brood stock developnient in CMF!^. Stocking density @ 4 prau^ns per cubic meter (sex ratio I : Ij was found ideal. Three tanks of the above size can meet the broodstock requirements of a hatchery of 18 million capacity. Unilateral eyestalk abJatton of females proved to be effective. Electrocautery apparatus was usedfor this purpose. Experiments also revealed that unablated P. indicus, can also be induced to mature and spauin by environmental and feed manipulation. Unablated P. indicus maintained in recirculation system and fed with intertidal oligochaetes, clam and squid meat attained maturity and spawned repeatedly over a prolonged period. Maintaining the pH of water between 8-8.2 and controlling the light intensity in broodstock tanks found to hasten maturation.