Shrimp
[2] They swim forward by paddling with swimmerets on the underside of their abdomens, although their escape response is typically repeated flicks with the tail driving them backwards very quickly.
Larger shrimp are more likely to be targeted commercially and are often referred to as prawns, particularly in the Commonwealth of Nations and former British colonies.
Historically, it was the distinction between walking and swimming that formed the primary taxonomic division into the former suborders Natantia and Reptantia.
Members of the Natantia (shrimp in the broader sense) were adapted for swimming while the Reptantia (crabs, lobsters, etc.)
The body of the shrimp is divided into two main parts: the head and thorax which are fused together to form the cephalothorax, and a long narrow abdomen.
The antennae have sensors on them which allow the shrimp to feel where they touch, and also allow them to "smell" or "taste" things by sampling the chemicals in the water.
Although shrimp are almost entirely fully aquatic, the two species of Merguia are semi-terrestrial and spend a significant part of their life on land in mangrove.
[12] The caridean family of pistol shrimp are characterized by big asymmetrical claws, the larger of which can produce a loud snapping sound.
[22] Colonies of snapping shrimp are a major source of noise in the ocean and can interfere with sonar and underwater communication.
[16] Females of the freshwater shrimp Caridina ensifera are capable of storing sperm from multiple partners, and thus can produce progeny with different paternities.
Female choice may increase the fitness of progeny by reducing inbreeding depression that ordinarily results from the expression of homozygous deleterious recessive mutations.
"On this basis, taxonomic classifications now divide the order Decapoda into the two suborders: Dendrobranchiata for the largest shrimp clade, and Pleocyemata for all other decapods.
[43][44] Some mantis shrimp are a foot long, and have bulging eyes, a flattened tail and formidable claws equipped with clubs or sharp spikes, which it can use to knock out its opponents.
[60][61] The evidence was circumstantial, because the chitinous shells of shrimp are so thin they degrade rapidly, leaving no fossil remains.
[64] In the 3rd century AD, the Greek author Athenaeus wrote in his literary work, Deipnosophistae; "... of all fish the daintiest is a young shrimp in fig leaves.
[64] In 1735 beach seines were imported from France, and Cajun fishermen in Louisiana started catching white shrimp and drying them in the sun, as they still do today.
Some immigrants starting catching shrimp local to San Francisco Bay, particularly the small inch long Crangon franciscorum.
Trawling was first recorded in England in 1376, when King Edward III received a request that he ban this new and destructive way of fishing.
Power winches were connected to the engines, and only small crews were needed to rapidly lift heavy nets on board and empty them.
New fishing grounds could be explored, trawls could be deployed in deeper offshore waters, and shrimp could be tracked and caught round the year, instead of seasonally as in earlier times.
[94] Worldwide, shrimp trawl fisheries generate about 2% of the world's catch of fish in weight, but result in more than one third of the global bycatch total.
Commercial shrimp farming began in the 1970s, and production grew steeply, particularly to match the market demands of the United States, Japan and Western Europe.
The total global production of farmed shrimp reached more than 1.6 million tonnes in 2003, representing a value of nearly 9 billion U.S. dollars.
[59] In the earlier years of marine shrimp farming the preferred species was the large giant tiger prawn.
It is a moderately large shrimp reaching a total length of 230 mm (9"), and is particularly suited to farming because it "breeds well in captivity, can be stocked at small sizes, grows fast and at uniform rates, has comparatively low protein requirements... and adapts well to variable environmental conditions.
Most farmed shrimp is exported to the United States, the European Union and Japan,[98] also other Asian markets, including South Korea, Hong Kong, Taiwan and Singapore.
[95] Investigations by The Guardian in 2014 and The Associated Press in 2015 found human rights abuses on fishing boats operated by Thailand.
Common welfare concerns include water pollution, high population densities, and the spread of diseases.
There is no reason to avoid using the terms shrimp or prawn when convenient, but it is important not to confuse them with the names or relationships of actual taxa.
[12] According to the crustacean taxonomist Tin-Yam Chan, "The terms shrimp and prawn have no definite reference to any known taxonomic groups.
