The giant river prawn, scientifically known as Macrobrachium rosenbergii, is a large species of freshwater prawn that has gained widespread recognition. Also referred to as the giant freshwater prawn or Malaysian prawn, it is a commercially important member of the Palaemonidae family. Its considerable size and adaptability make it a notable species.
Physical Characteristics and Habitat
The giant river prawn has distinct physical features. Its body is greenish to brownish-grey, with larger individuals sometimes displaying a bluish hue. This species is characterized by a smooth carapace and a long, slender, slightly upward-curving rostrum, adorned with 11 to 14 dorsal teeth and 8 to 10 ventral teeth.
A notable characteristic of the male giant river prawn is its second pair of walking legs. These are larger and thicker than those of the female, often appearing blue or orange and extending beyond the rostrum. These chelipeds are covered in dense bristles. The prawn’s natural range spans tropical and subtropical regions of the Indo-Pacific, from India to Southeast Asia and Northern Australia. It inhabits freshwater environments such as rivers, lakes, ponds, ditches, canals, and estuaries, often preferring shallow, detritus-rich, and vegetated areas.
Life Cycle and Reproduction
The life cycle of the giant river prawn involves several stages, from egg to adult. Females carry thousands of eggs, which are bright orange and become grey-black a few days before hatching. Embryonic development lasts about three weeks.
Upon hatching, free-swimming zoeae larvae emerge. These larvae are planktonic and require brackish water for survival, undergoing multiple larval stages over 30 to 45 days before metamorphosing into post-larvae (PL). Post-larvae then migrate upstream to freshwater environments, where they adopt a more benthic lifestyle and develop into juveniles and adults.
Aquaculture and Economic Importance
The giant river prawn is significant in global aquaculture as a food source. Modern farming began around the 1960s, with methods for mass producing post-larvae developed in Malaysia and Hawaii. Global aquaculture production of Macrobrachium rosenbergii reached 313,000 metric tons in 2021, valued at $2.45 billion.
Farming methods include pond culture, tank systems, and hatchery practices. Hatcheries produce post-larvae, which are then transferred to grow-out farms to be raised to marketable sizes. China is the leading producer, accounting for over half of global production, followed by Bangladesh, Thailand, Myanmar, and India. Its adaptability to various culture systems, including polyculture with fish and rice, enhances its economic viability.
Culinary Uses
The giant river prawn is valued in various cuisines, particularly in Southeast Asia, for its distinct taste and texture. Its flesh is often compared to lobster, with a firmer texture and sweeter flavor. It is prepared in numerous ways.
Common preparation methods include grilling, frying, and incorporating it into curries and soups. In India and Bangladesh, it is known as “golda chingri” and is a popular ingredient in many traditional dishes. Nutritionally, the prawn meat is a good source of protein, containing over 17% protein and 4% fat.