Procambarus clarkii

Procambarus clarkii
Conservation status
Least Concern
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Order:	Decapoda
Infraorder:	Astacidea
Family:	Cambaridae
Genus:	Procambarus
Subgenus:	P. (Scapulicambarus)
Species:	P. clarkii
Binomial name
Procambarus clarkii Girard, 1852

Procambarus clarkii is a freshwater crayfish species, native to the Southeastern United States, but found also on other continents, where it is often an invasive pest. It is known variously as the red swamp crawfish, red swamp crayfish, Louisiana crawfish or Louisiana crayfish.

Range and range expansion

The native range of P. clarkii is along the Gulf Coast from northern Mexico to the Florida panhandle, as well as inland, to southern Illinois and Ohio. It has also been introduced, sometimes deliberately, outside its natural range to countries in Asia, Africa, Europe and elsewhere in the Americas. In northern Europe, the populations are self maintaining but not expanding, while in southern Europe, P. clarkii is multiplying and actively colonising new territory, at the expense of the native crayfish, Astacus astacus and Austropotamobius spp.. Individuals are reported to be able to cross many miles of relatively dry ground, especially in wet seasons, although the aquarium trade and anglers may have hastened the spread in some areas (it is believed that anglers using P. clarkii as bait introduced it to the American state of Washington). Attempts have also been made to use P. clarkii as a biological control organism, to reduce levels of the snails involved in the life cycle of schistosomiasis, leading to the dispersal of P. clarkii in, for instance, Kenya.

Ecology

Red swamp crayfish, dorsal view

P. clarkii is most commonly found in warm fresh water, such as slowly-flowing rivers, marshes, reservoirs, irrigation systems and rice paddies. It is considered to be the most ecologically plastic species in the Order Decapoda, and is able to grow quickly even in only seasonally present water, being able to tolerate dry spells of up to four months. P. clarkii grows quickly, and is capable of reaching weights in excess of 50 g, and sizes of 5½–12 cm long. It is also able to tolerate slightly saline water, which is unusual for a crayfish. The average lifetime of Procambarus clarkii is 5 years. It is known that some individuals have reached ages (in nature) over 6 years.

Economic importance

The rapid growth and ecological tolerance of P. clarkii facilitates a large farming industry in Louisiana, worth millions of dollars annually, and with more than 500 km² in cultivation. Harvests of P. clarkii account for a large majority of the crayfish produced in the United States and elsewhere. P. clarkii has also been introduced elsewhere for cultivation, such as Spain, where its success is attributable to its ability to colonise disturbed habitats that would be unsuitable for the native crayfish. P. clarkii is also marketed by biological supply companies for teaching and research. P. clarkii also exhibits different color morphs, including white, blue, and orange.

Ecological impacts

The burrowing activities of P. clarkii can lead to damage to water courses and to crops, particularly rice crops, and its feeding can disrupt native ecosystems. It may out-compete the native crayfish species, and is a vector for the crayfish plague fungus Aphanomyces astaci, for crayfish virus vibriosis and a number of worms parasitic on vertebrates.

Reproduction

Procambarus clarkii normally reproduces sexually, but recent research suggests it may also reproduce by parthenogenesis. ^[1]

Procambarus clarkii as Food

Boiled crayfish, Louisiana

Procambarus clarkii are eaten in Europe, China, Africa, Australia, Canada, New Zealand and the United States and the Caribbean. 98% of the crayfish harvested in the United States come from Louisiana, where the standard culinary terms are crawfish or écrevisses.

Louisiana produces 90 percent of the crawfish in the world and consumes 70 percent locally.^[2]

Louisiana crawfish are usually boiled in a large pot with heavy seasoning (salt, cayenne pepper, lemon, garlic, bay leaves, etc.) and other items such as potatoes, corn on the cob, onions, garlic, and sausage. There are many differing methods used to season a crawfish boil and an equal number of opinions on which one is correct. ^[3] They are generally served at a gathering known as a crawfish boil.

Miscellany

Procambarus clarkii was named by Charles Frédéric Girard in honour of John H. Clark, who surveyed the US-Mexican border in 1851.^{[citation needed]}

References

• Girard C. (1852). "A Revision of the North American Astaci, with Observations on Their Habits and Geographic Distribution". Proc. Acad. Nat. Sci. Philad. 6: 87–91. 
• UCN 2007. 2007 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Downloaded on 14 October 2007.
• M. James Norrocky (1991). "Observations on the Ecology, Reproduction and Growth of the Burrowing Crayfish Fallicambarus (Creaserinus) fodiens (Decapoda: Cambaridae) in North-central Ohio". American Midland Naturalist 125: 75–86. doi:10.2307/2426371. 

External links

• Procambarus clarkii at Animal Diversity Web

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