Whiteleg shrimp
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Whiteleg shrimp (Litopenaeus vannamei, synonym Penaeus vannamei), also known as Pacific white shrimp or King prawn or White shrimp, is a species of prawn of the eastern Pacific Ocean commonly caught or farmed for food.
Description
Litopenaeus vannamei grows to a maximum length of Template:Convert, with a carapace length of Template:Convert.<ref name="FAO"/> Adults live in the ocean, at depths to Template:Convert, while juveniles live in estuaries.<ref name="FAO"/> The rostrum is moderately long, with 7–10 teeth on the dorsal side and two to four teeth on the ventral side.<ref name="FAO"/> The global production of white shrimp had increased to approximately 5 million metric tons, with a market value reaching USD 30 billion in 2018.<ref>Template:Cite web</ref>
Distribution and habitat
Whiteleg shrimp are native to the eastern Pacific Ocean, from the Mexican state of Sonora to as far south as northern Peru.<ref name="FAO">Template:Cite web</ref> It is a euryhaline tropical shrimp species capable of growing in salinities ranging from 0 to 40‰,<ref>Template:Cite journal</ref> with the optimal salinity for growth being between 15 and 25‰.<ref>Template:Cite journal</ref> The optimal pH for white shrimp is approximately 7.56,<ref>Template:Cite journal</ref> and dissolved oxygen levels should be maintained above 2.8 mg/L.<ref>Template:Cite journal</ref> Whiteleg shrimp can grow in water temperatures ranging from 15 °C to 38 °C, with the optimal growth temperature between 22 °C and 35 °C; it is restricted to areas where the water temperatures remain above Template:Convert throughout the year.<ref name="CASIP"/>
Fishery and aquaculture
Template:More citations needed section During the 20th century, L.vannamei was an important species for Mexican inshore fishermen, as well as for trawlers further offshore.<ref name="FAO"/> In the late 20th century, the wild fishery was overtaken by the development of aquaculture production; this began in 1973 in Florida using prawns captured in Panama, that were used in hatcheries for larvae production.<ref name="CASIP">Template:Cite web</ref>
In Latin America, the cultivation of L. vannamei expanded with improvements such as the availability of hatchery-produced larvae, advances in feed formulation, modernization of farming techniques, development of freezing facilities, and establishment of market distribution channels.<ref name=":1">Template:Cite web</ref> From Mexico to Peru, most countries developed large production areas in the 70s and 80s. Ecuador has become one of the world’s leading producers of whiteleg shrimp.<ref name=":1" />
Around the beginning of the 21st century, Asia introduced this species in their aquaculture operations (changing from Penaeus monodon). China, Vietnam, India and others have become major packers as well.<ref name=":1" /> The packing of shrimp from aquaculture origin has surpassed the quantity of ocean caught wild shrimp in recent years.Template:When Both wild-caught and farmed shrimp are affected by environmental conditions and disease outbreaks.<ref>Template:Cite journal</ref>
By 2004, the production of white shrimp had reached 1,116,000 metric tons, surpassing that of black tiger shrimp.<ref>Template:Cite web</ref> According to statistics from the Food and Agriculture Organization (FAO), shrimp farming accounted for 18% of the total global aquaculture trade volume in 2018. In 2017, the global shrimp production was approximately 5,511,914 metric tons, with white shrimp accounting for 80% of the total production.<ref>Template:Cite web</ref>
Litopenaeus vannamei have been cultivated indoors through a recirculating aquaculture system in Downey, California.<ref>Template:Cite web</ref>
Weather effect
Normally, there are peaks of production during the warm El Niño years, and reduced production during the cooler La Niña years. The effect is on ocean caught as well as on aquaculture origin.Template:Citation needed
Diseases
Litopenaeus vannamei farming has been affected by several pathogens, which have caused significant economic losses in the shrimp aquaculture industry.<ref>Template:Cite journal</ref> There are several known diseases.<ref name="CASIP"/> Production of L.vannamei is limited by its susceptibility to white spot syndrome, Taura syndrome, infectious hypodermal and haematopoietic necrosis, baculoviral midgut gland necrosis, and Vibrio infections.<ref name="CASIP" /> Acute hepatopancreatic necrosis syndrome (AHPND), caused by Vibrio parahaemolyticus, was initially referred to as Early Mortality Syndrome (EMS). It has caused significant economic losses in the white shrimp aquaculture industry.<ref>Template:Cite journal</ref> Vibrio harveyi and Vibrio alginolyticus are also among the commonly found Vibrio species.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
In aquaculture, the use of antibiotics or chemical agents has been associated with environmental pollution and drug residue concerns. As a result, practices have increasingly shifted toward improving pond conditions and enhancing the immune response of white shrimp. Approaches such as water quality management, incorporation of probiotics into feed, and application of immunostimulants have been reported to be effective in reducing the risk of large-scale disease outbreaks.<ref>Template:Cite journal</ref> Probiotics have been widely applied in feed and aquaculture environments to improve water quality and enhance the immunity of cultured organisms, thereby reducing disease incidence and helping prevent outbreaks.<ref>Template:Cite journal</ref>
Impact on nature
In 2010, Greenpeace International added the whiteleg shrimp to its seafood red list. This lists fish that are commonly sold in supermarkets around the world, and which have a very high risk of being sourced from unsustainable fisheries.<ref name="redlist">Greenpeace International Seafood Red list</ref> The reasons given by Greenpeace were "destruction of vast areas of mangroves in several countries, overfishing of juvenile shrimp from the wild to supply shrimp farms, and significant human rights abuses".<ref name=redlist/> In 2016, L.vannamei accounted for 53% of the total production of farmed crustaceans globally.<ref>Template:Citation</ref>
Immune mechanism
Crustaceans primarily rely on non-specific immune responses,<ref>Template:Cite journal</ref> which can be further categorized into cellular immune responses and humoral immune responses.<ref>Template:Citation</ref>
- Cellular immune responses<ref name=":0">Template:Cite journal</ref>: cellular components include all reactions mediated directly by haemocytes, such as phagocytosis, encapsulation, and nodule formation.<ref>Template:Cite journal</ref> Crustacean haemocytes are commonly classified into three distinct types: hyaline cells, semigranular cells (SGCs), and granular cells (GCs).<ref>Template:Cite journal</ref> Hyaline cells, the smallest of the three haemocyte types, are agranular and function as the primary active phagocytes<ref name=":0" />. SGCs contain numerous small eosinophilic granules and play a key role in microorganism recognition, being involved in encapsulation, coagulation, and occasional phagocytosis<ref name=":0" />. Granules of granular cells (GCs) contain prophenoloxidase (proPO), which is stored in an inactive form, as well as antimicrobial peptides (AMPs), protease inhibitors, and a cell adhesion/degranulating factor called peroxinectin.<ref>Template:Cite journal</ref>
- Humoral immune responses<ref name=":0" />: humoral components primarily consist of the prophenoloxidase-activating system, agglutinins, protease inhibitors, antimicrobial peptides (AMPs), phosphatases, lysozymes, clotting proteins, and reactive oxygen or nitrogen intermediates.<ref>Template:Cite journal</ref> It also includes substances present in the hemolymph that recognize foreign agents and initiate immune responses, such as lipopolysaccharide- and β-1,3-glucan-binding protein (LGBP), lectins, clotting agents, and Toll-like receptors.<ref>Template:Cite journal</ref> Upon hemocyte lysis, lectins are released, which contribute to pathogen recognition and assist in phagocytosis and agglutination.<ref>Template:Cite journal</ref>
See also
- Macrobrachium rosenbergii, the giant freshwater prawns
- Pandalus borealis, Canadian northern prawns
References
External links
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