Prawns are swimming decapod crustaceans characterized by ten legs and segmented bodies encased in a hard exoskeleton. These aquatic animals are found across the globe, inhabiting various water environments from deep ocean floors to inland rivers. The name “prawn” is often used broadly in commercial and culinary contexts to refer to any large, edible swimming crustacean. True prawns, along with their close relatives, thrive in a diverse range of conditions and locations.
Distinguishing Prawns from Shrimp
The terms prawn and shrimp are frequently used interchangeably, but they refer to two distinct biological groups of decapod crustaceans. True prawns belong to the suborder Dendrobranchiata, while most true shrimp are classified under Pleocyemata. Prawns possess a straighter body shape because their abdominal segments overlap sequentially, like tiles on a roof, from front to back. In contrast, shrimp have a more noticeable curve because the second abdominal segment overlaps both the first and third segments.
Prawns also have branching gills, which resemble small trees, while shrimp have plate-like, or lamellar, gills. Prawns have three pairs of clawed legs, with the second pair of pincers typically being the largest, whereas shrimp usually have claws on only two pairs of legs.
Global Distribution and Primary Habitats
Prawns are found worldwide and their existence is tied to three primary types of aquatic environments: marine, freshwater, and brackish water. The vast majority of species are marine, belonging to the family Penaeidae, and inhabit tropical and subtropical seas. These species are typically bottom-dwellers, living on sandy or muddy substrates on the continental shelf, ranging from shallow coastal areas to depths of over 400 meters.
Many marine prawn species follow a life cycle that necessitates migration between different salinity levels. Adults spawn in the open ocean, and the resulting postlarvae migrate toward the coast to spend their juvenile stages in brackish water. This transitional habitat, found in estuaries, river mouths, and mangrove swamps, provides nutrient-rich, sheltered conditions with a salinity level lower than the sea but higher than freshwater.
Freshwater prawns, primarily those of the genus Macrobrachium, live their adult lives in inland rivers, lakes, and streams across tropical regions. These species also participate in a migratory cycle, where the adults move downstream to release their eggs in brackish water environments. The larvae require this intermediate salinity to develop, but once they metamorphose into juveniles, they journey back upstream to mature in pure freshwater.
Major Commercial Species and Their Locations
The commercial prawn industry is dominated by a few species whose global distribution is often a mix of natural range and widespread aquaculture.
Giant Tiger Prawn (Penaeus monodon)
This species naturally inhabits the Indo-Pacific region, from East Africa and the Arabian Peninsula across Southeast Asia to Australia and Japan. Its large size and rapid growth made it a primary target for aquaculture, leading to its extensive farming in countries like Vietnam, Thailand, and India.
Whiteleg Prawn (Litopenaeus vannamei)
The Whiteleg Prawn is another globally important species, although it is taxonomically a shrimp that is commercially marketed as a prawn. Its native range is the Eastern Pacific coast, extending from Sonora, Mexico, south to Tumbes, Peru, where it thrives in warm, tropical marine and estuarine waters. Due to its hardiness and suitability for intensive farming, it has become the most widely cultured species globally, with massive production now centered in Asian countries like China, Thailand, and Indonesia, far outside its original range.
Giant River Prawn (Macrobrachium rosenbergii)
The Giant River Prawn represents the freshwater segment of the industry, native to the tropical and subtropical areas of the Indo-Pacific, including India, Southeast Asia, and Northern Australia. This species is cultivated extensively in the freshwater river systems of the same region, where it is valued for its large size and distinct flavor. Its unique life cycle, which requires adults to live in freshwater but larvae to develop in brackish water, dictates that farming operations must be located near coastal river systems or employ specialized hatchery techniques.