Procambarus clarkii

Origin

 * This Cray is native to the Southeastern United States.


 * Although captive fisheries for introduced Procambarus clarkii exist in several other countries (such as China, Spain, and Portugal), there is no place where crayfish are more highly regarded socially and have had as much impact to the economy of a region than in the southern United States. Crawfish are cultivated and consumed for food in several southern states but Louisiana dominates the crawfish industry of North America in both aquaculture and wild capture fisheries, where the industry contributes well in excess of USD 150 million to the state's economy annually. Commercial sales of crawfish from natural waters began in Louisiana in the late 1800s, and with the development of improved transportation and cold storage, crawfish markets shifted from local consumption in rural areas to higher-volume markets in cities such as Baton Rouge and New Orleans, and beyond. Annual supplies of wild harvests were extremely variable from year to year and the season was often short-lived. Therefore, entrepreneurs began experimenting with the farming of crawfish by the mid 20th century as a source of more dependable supplies. Pond culture of crawfish soon became integrated with other farming operations, and today, pond-reared crawfish constitutes the majority of the annual harvest. Over the last decade, farm-reared crawfish have accounted for well over 75 percent of the total harvest. Approximately 48 000 ha are devoted to the culture of crawfish in Louisiana and the state accounts for about 90-95 percent of the total production in the USA.

Reproduction/ Sexing

 * The male crayfish's first set of swimmerets are longer and more prong shaped. Testes are usually white, while ovaries are usually orange. The female crayfish has a seminal receptacle to receive sperm from the male.


 * The red swamp crayfish mate in late autumn. The location of gonads are similar in both males and females -just anterior to the heart. Testes are usually white, while ovaries are usually orange. The sperm cells (crayfish sperm lack tails and are sometimes referred to as spermatophores) are released from the body of male crayfish through a pore at the base of the fifth pair of walking legs. Fertilization is internal. Sperm enters the female at the base of the third pair of walking legs, where the eggs are fertilized and released. The female crayfish then lies on her back and curls her abdomen forward. By beating her pleopods, or swimmerets, the female creates a water current which drives the fertilized eggs into the swimmerets where they will remain for approximately 6 weeks. By spring, the eggs will become larvae, and remain on the mother until sexually mature. The red swamp crayfish reach maturity in as little as three months, and in warm climates can reproduce two generations per year. Large healthy females typically produce over 600 viable young.

Tank compatibility

 * These Crayfish can be furiously territorial and aggressive to other Crayfish and any other inhabitants that don't get out of their way. A large tank is thus required and only compatible with species that will give it a wide berth. This species should not be kept with long finned fish or slow fish because those fish are easy targets for the crayfish. Do not mix with other species of crayfish. In addition multiple crayfish should only be kept together if they are roughly the same size otherwise the larger and more powerful crayfish will eat the smaller one.


 * They are also alleged to be nocturnal predators that ambush and devour fish that sleep on the tank bottom at night. Therefore, fish that exclusively inhabit the top strata such as hatchet fish are recommended.

Diet

 * Pretty much anything it can get its claws on. From sinking food pellets, soft vegetation, detritus and co-inhabitants. It can also eat bloodworms and frozen algae. Do not feed shrimp to this species of crayfish since the former harbour diseases that can be fatal to crayfish. Crustacean specific pellets are recommended.


 * In the wild, they tend to prey on water snails, insect larvae and tadpoles, being mostly predatory and carnivorous unlike other crayfish species. When traditional food sources are scarce, the crayfish eat the remains of dead animals and worms as well.

Feeding regime

 * Feed once or twice a day.

Environment Specifics

 * As the common name implies, red swamp crayfish are found mainly in swamps, sloughs, and ditches. This species avoids streams and areas with strong current. During periods of drought or cold, the red swamp crayfish burrows itself for survival (McDonald 1996). It prefers substrates of mud or sand, often where there is plenty of organic debris such as logs, sticks or water-soaked tree leaves. It generally avoids streams and ditches with strong flow, where it is replaced by the White River crayfish. The red swamp crayfish burrows during periods of drought or cold.


 * These Crayfish will seriously disrupt any vegetation or decoration. They can be very active and will often attempt to escape. It is imperative that these animals are provided with a substrate they can burrow in as well as adequate hiding spaces such as a clay pipe or hollow bogwood.

Behaviour

 * An aggressive species of crayfish that will harass the other inhabitants of the aquarium. Thus crayfish should be given a lot of room with an adequate amount of hiding places. These Crayfish are cannibalistic.

Identification

 * A large Cray which is available in several colour forms. The wild form is brown-red, orange, blue and white morphs are also available. Although many sites state that they reach a maximum size of 5 inches, the reality is that they can keep expanding as long as they do not face intense competition for food.