Macrobrachium rosenbergii, also known as the giant river prawn or giant freshwater prawn, is a commercially important species of palaemonid freshwater prawn. It is native throughout the tropical and subtropical areas of the Indo-Pacific region, from India to Southeast Asia and Northern Australia. and Thailand prawn in Southern China and Taiwan (Chinese: Tàiguó xiā 泰國蝦).
It is one of the biggest freshwater prawns in the world, and is widely cultivated in several countries for food. Due to accidental releases, the giant freshwater prawn has also been introduced to parts of Africa, China, Japan, New Zealand, the Americas, and the Caribbean. with total lengths of for males and for females. The first stage is called "small male" (SM); this smallest stage has short, nearly translucent claws. If conditions allow, small males grow and metamorphose into "orange claws" (OC), which have large orange claws on their second chelipeds, which may have a length of 0.8 to 1.4 times their body size. The species is aquacultured throughout the tropics.
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File:56Ulang giant river prawn 19.jpg|Raw
File:Kung kam kram.jpg|Grilled giant river prawns in Thai cuisine, each (whole) prawn weighing around 500 g
File:Kung yang.JPG|Thai kung yang, or grilled prawns
File:9977Foods cuisine of Bulacan 09.jpg|Cooked
File:16Halabos na Ulang 22.jpg|Peeled
File:9246Tambubong Caingin Sampaloc, San Rafael Road, Bulacan 28.jpg|Sold in the Philippines
File:Giant river prawn total production thousand tonnes 1950-2022.svg|Capture (blue) and aquaculture (green) production of Giant river prawn (Macrobrachium rosenbergii) in thousand tonnes from 1950 to 2022, as reported by the FAO
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In research
Professor Amir Sagi and his research group from the Ben-Gurion University of the Negev have found the IAG physiological sexual switch, and its associated gene expression in decapods investigating multigenic functions in crustacean reproduction and growth and the establishment of genome editing in prawns using application of CRISPR.
His group established monosex biotechnologies in crustacean culture including the application of temporal RNA interference (RNAi) in the field of aquaculture for all-male culture. Crustacean monosex technologies are applied in Vietnam, Thailand, China, Malaysia, Israel. He is a co-founder of the all-female culture biotech company Enzootic Ltd.
Prawns are efficient predators thus might serve as sustainable and responsible biocontrol agents over various invasive and pest species.