The Indian prawn (Fenneropenaeus indicus, formerly Penaeus indicus) is one of the major commercial prawn species of the world. It is found in the Indo-West Pacific from eastern and south-eastern Africa, through India, Malaysia and Indonesia to southern China and northern Australia. Adult shrimp grow to a length of about and live on the seabed to depths of about . The early developmental stages take place in the sea before the larvae move into estuaries. They return to the sea as sub-adults.
The Indian prawn is used for human consumption and is the subject of a sea fishery, particularly in China, India, Indonesia, Vietnam and Thailand. It is also the subject of an aquaculture industry, the main countries involved in this being Saudi Arabia, Vietnam, Iran and India. For this, wild seed is collected or young shrimps are reared in hatcheries and kept in ponds as they grow. The ponds may be either extensive with reliance on natural foods, with rice paddy fields being used in India after the monsoon period, or semi-intensive or intensive, with controlled feeding. Harvesting is by drainage of the pond.
Common names
F. indicus is known by many common names around the world, including Indian white prawn, Tugela prawn, white prawn, The name white shrimp may also refer to other species.
Ecology and life cycle
F. indicus is a marine decapod with estuarine juveniles. It prefers mud or sandy mud at depths of . It is also commonly used in shrimp farming.
Fisheries and aquaculture
The world's production of shrimp is about 6 million tonnes, of which approximately 3.4 million tonnes is contributed by capture fisheries and 2.4 tonnes by aquaculture. China and four other Asian countries, including India, Indonesia, Vietnam and Thailand, together account for 55% of the capture fisheries.
Among the shrimp, the contribution of F. indicus to global fisheries was around 2.4%,
Aquaculture
Production cycle of F. indicus follows the same steps as for other species of shrimp, i.e., seed production and Grow-out of the post larvae to marketable size. The sources of seeds and grow-out techniques can be differed as desired by the farmer to achieve a balance between the cost of production and the desired quantity of output.
Supply of seeds
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%. 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
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. A temperature range of and salinity of 30‰–35‰ is ideal for spawning. However it is expensive to raise spawners in captivity and ablated shrimps result in less hardy fry with low survival rate. the hatch rates of ablated females was found to be markedly less (37.8% to 58.1%) than that of unablated females (69.2%). The protozoea stage is supplied with a mixed culture of diatoms dominated by Chaetoceros spp. at a concentration on around 30,000 to 40,000 cells per ml. The best algal density promoting highest survival, growth and fastest larval development is around 60–70 cells per μL. It takes an average of 150–180 days for a single crop to be ready to harvest. The estimated production of prawn-cum-paddy culture varies from 400 to 1200 kg/ha for six months period. F. indicus forms about 36%–43% of the total yield of shrimp which can go up to 400–900 kg/ha/yr. Extensive culture can be made more productive by construction of artificial ponds, use of aeration and supplementing with artificial diet. This can increase the productivity to 871.5 kg/ha/320 days in mixed culture of prawns. Stock densities can range from 20–25 PL/m2 using hatchery derived seeds for monoculture. Natural feeds are grown by application of fertilizers and supplementary feeds are also given during the culture at a rate of 4–5 times a day.