Indian prawn

The Indian prawn, known scientifically as Fenneropenaeus indicus, is a major commercial species of crustacean. It is a marine decapod, which means it is a sea creature with ten legs. This species is highly valued for human consumption across the globe. It plays a significant role in both wild fisheries and the aquaculture industry. Many people know it by different common names. These include the white prawn, the banana prawn, and the red leg banana prawn.

The life cycle of the Indian prawn involves several distinct developmental stages. It begins in the open sea after hatching as free-swimming nauplii. These tiny organisms then progress through the protozoea and mysis stages. Eventually, they reach the postlarval stage, which looks much more like an adult. These postlarvae migrate into estuaries, which are areas where river water meets the sea. They feed and grow in these sheltered waters until they reach a length of 110 to 120 mm. Once they become sub-adults, they return to the sea to complete their life cycle.

Farmers use aquaculture, or water farming, to raise these prawns for food. There are three primary methods of production: extensive, semi-intensive, and intensive. Extensive farming is a traditional method that relies on natural foods. In India, farmers sometimes use 'pokkali' rice paddy fields for this purpose after the monsoon season. Semi-intensive farming uses smaller ponds that are deeper, usually between 1.0 and 1.5 meters. This method uses hatchery-derived seeds and provides supplementary feed several times a day. Intensive farming is a highly controlled and mechanized system. It uses very high stocking densities of 50 to 100 postlarvae per square meter.

To start a farm, producers must secure a steady supply of seeds. These seeds can be collected from the wild or produced in hatcheries. In traditional systems, juveniles enter fields through sluice gates during high tide. However, many modern farmers now rely on hatcheries to reduce dependence on wild seeds. Hatcheries require broodstock, which are adult prawns used for breeding. Spawners can be collected from the wild during peak seasons in March, April, July, or August. In some hatcheries, scientists use a technique called eyestalk ablation to stimulate hormone activity. This process can encourage females to spawn, though it may result in lower hatch rates compared to wild females.

In a hatchery, larvae are reared in circular tanks with specific water conditions. The salinity is maintained at approximately 32 parts per thousand, and the pH is kept at 8.2. The nauplius stage does not require feeding, but the protozoea stage is fed a culture of diatoms. As they reach the mysis stage, they are fed artemia nauplii and an egg-prawn-custard mix. Postlarvae are fed minced mussel meat or mantis shrimp powder until they reach the PL-20 stage. After 20 days, they are ready to be moved into grow-out ponds.

The global shrimp industry is massive, with a total production of about 6 million tonnes. Of this, approximately 3.4 million tonnes come from capture fisheries and 2.4 million tonnes come from aquaculture. In 2005, the Indian prawn contributed about 2.4% to global fisheries and 1.2% to global farmed shrimp production. Saudi Arabia was a leading producer in 2005, producing nearly 11,300 tonnes. Vietnam followed closely with 10,000 tonnes. While the Indian prawn has a lower market value than the Penaeus monodon, it is often more profitable because it is easier to breed and rear.

While the Indian prawn is a vital resource, there are environmental concerns regarding its harvest. In 2010, Greenpeace International added the species to its seafood red list. This was not because the prawns themselves are threatened with extinction. Instead, the concern is the high amount of bycatch caused by fishing methods. Bycatch occurs when other animals are caught accidentally during the process. This can include endangered species, such as sea turtles. Managing how we catch these prawns is essential to protecting the broader marine ecosystem.