Shrimp, an animal found in both freshwater and saltwater throughout the world. Like its relatives the lobsters, crabs, and crayfish, the shrimp is a crustacean. Shrimp are a popular seafood and a valuable commercial item. However, of the more than 1,900 species of shrimp, fewer than 20 are important commercially.
In the United States, the species that are most important commercially are the white shrimp, the brown shrimp, and the pink shrimp. Most of the shrimp marketed in the United States are bred and raised in large tanks under scientifically controlled conditions. However, some shrimp are still fished in the traditional manner; special nets, called otter trawls, are used to catch them. Shrimp are marketed chiefly fresh or frozen, but some are canned or dried. The shells are used to make animal feed.
As their name suggests, shrimp are not big. Not even a “jumbo” shrimp is big, compared with an adult American lobster.
Most shrimp are less than 8 inches (20 centimeters) long. In addition to their size differences, shrimp and lobster also have different modes of locomotion. Lobsters usually crawl. Most shrimp are swimmers.
Many shrimp differ from lobsters in yet another way. Female lobsters carry their eggs. Many large shrimp do not. Instead, female shrimp release their eggs in the sea.
There are also freshwater shrimp, but no freshwater lobsters. Fairy shrimp, which swim continuously on their backs, are an example of freshwater shrimp.
Adult shrimp range in length from less than 1 inch (2.5 cm) to more than 12 inches (30 cm), depending on the species. Most of the species caught commercially have an adult length of 3 to 9 inches (7.5 to 23 cm). Those that are more than 5 inches (13 cm) long are often called jumbo shrimp, or prawns. The shrimp's body is long and narrow and slightly compressed from side to side. It is covered by a translucent shell called an exoskeleton. Shrimp periodically molt (shed their outer covering). Shrimp may be gray, white, pink, brown, or green, often with various markings. Many species can change color to blend with their surroundings.
The body of the shrimp is divided into two distinct regions—the cephalothorax (a fused head and thorax) and the abdomen. (It is the abdomen that is usually eaten, often after the vein found on the back is removed.) The cephalothorax bears a pair of compound eyes and usually 13 pairs of appendages. Listed from front to back, these appendages are: two pairs of antennae (one pair much longer than the other); a pair of jaws (called mandibles); two pairs of accessory jaws, called maxillae; three additional pairs of accessory jaws, called maxillipeds; and five pairs of legs. (The accessory jaws serve many functions, including grasping, biting, and swimming.)
The abdomen also bears appendages—five pairs of swimmerets (called pleopods and used for swimming); a pair of uropods (also used for swimming); and a telson, or tailpiece. The uropods and telson together make up the tail fan.
Shrimp are usually found on muddy or sandy bottoms. Some species burrow in the sand or mud; others burrow into rock and coral crevices. Many of the smaller species live inside sponges. Shrimp eat both plant and animal material. Reproduction is by eggs and sperm. Females usually carry the fertilized eggs on their swimmerets until they hatch.
Shrimp make up the suborder Natantia of the order Decapoda, class Malacostraca in the subphylum Crustacea. The white shrimp is Penaeus setiferus; the brown, P. aztecus; the pink, P. duorarum. Crangon vulgaris is a common European species.