Although crayfish inhabitat many regions of the Earth, members of the genus Procambarus are located in North America. Procambarus clarkii are mostly found south-central United States, and northeastern Mexico (areas to which this species is native). The red swamp crayfish has also been transplanted to Hawaii, Japan, and even the River Nile (Safra, et al 1999; Jarmon 1999).

Biogeographic Regions: nearctic (Native )

Global Range: (200,000-2,500,000 square km (about 80,000-1,000,000 square miles)) Native range extends from the Mississippi-Ohio confluence down the Mississippi River floodplain to Louisiana, and along the Gulf coastal Plain southwest to Alabama, to the Rio Grande basin in south New Mexico and north Mexico. Mexican distribution includes Baja California, Baja California Sur, Chihuahua, Sonora, Sinaloa, Durango, Coahuila, Nuevo Leon, and Tamaulipas (Hernandez et al., 2008). It was widely introduced in many places throughout Africa, Asia, and Europe, and also outside its native range in North America. (See Hobbs, 1989). Genetic variation in introduced European populations found to be high enough to uniquely fingerprint most of the surveyed individuals (Barbaresi et al., 2003) and a similar situation exists in Asia (Yue et al., 2010). In the United States, established non-native populations now occur in California, Nevada, Idaho, Illinois, New York, North Carolina, Ohio, Oregon, and Washington (Taylor and Schuster, 2004).

occurs (regularly, as a native taxon) in multiple nations

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Adults of this species are about 2.2 to 4.7 inches in length. Crayfish are characterized by a joined head and thorax, and a segmented body. In the case of the species Procambarus clarkii, the body is a very dark red color, with a wedge-shaped black stripe on the abdomen. Crayfish have a sharp snout and moveable eyes on their heads. Like all arthropods, crayfish have a thin but tough exoskeleton that they shed during development. Crayfish have 5 pairs of walking legs, the first of which are large pinchers used for feeding. On the red swamp crayfish, the pinchers tend to be narrow and long. They have long antennae with sensory organs on them. This along with appendages used for feeding, are characteristic of the subphylum Mandibulata. There are also five pairs of smaller appendages called swimmerets on the abdomen. The carapace of this species, located on the dorsal side, are not separated by a space. The most posterior pair of appendages are called uropods. Uropods are flat, broad extentions that surround the telson, which is the last abdominal segment. Uropods are also used for swimming (Safra, et al 1999; McDonald 1996; Vodopich and Moore 1999; Barnes 1974).

Male with hooks on ischia of 3rd & 4th pereiopods; male first pleopod with lobate cephgalic process sharply angled on caudodiostal margin and sharp angular shoulder on cephalic margin proximal to terminal elements; areola narrow to obliterated.

• Freshwater

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).

Habitat Type: Freshwater

Comments: In Missouri, it occurs more often in flowing water habitats than the white river crayfish (61% lowland streams and ditches, 79% of these with noticeable current or flow), but also in swamps, sloughs and roadside pools; bottom usually mud or sand, often where there were considerable quantities of organic debris such as logs, sticks or water-soaked tree leaves (Pflieger, 1996). It is very tolerant of low oxygen and high temperature; is a secondary burrower; and is found in almost every type habitat in sluggish streams and lentic situations. It is one of few North American crayfishes with salinity tolerance.

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Reports of migrations of males of several miles over comparatively dry areas, esp. in fall rainy season.

Although some crayfish are known to feed on vegetation, the red swamp crayfish is carnivorous, eating insect larvae, tadpoles, and snails. When traditional food sources are scarce, the crayfish eat the remains of dead animals and worms as well (Safra, et al 1999; Barnes 1974).

Comments: Opportunistic; thrives on various commercial "pet foods".

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: > 300

Comments: The species has been introduced to Massachusetts (University of Massachusetts campus pond, Amherst) and Rhode Island (University of Rhode Island campus pond, Kingston) (Smith, 2000). Recently it was found at a single in the Catawba River in North Carolina (Alderman, 2005). It has been introduced to all North Carolina river basins in the Piedmont Plateau and Coastal Plain (Cooper and Armstrong, 2007; Simmons and Fraley, 2010). It has been introduced in a variety of aquatic habitats in lentic areas in South Carolina across much of the state (Eversole and Jones, 2004).In Georgia, it has been introduced into a single stream in downtown Athens and a highly disturbed urban stream in Gwinnett Co. and an urban stream in the Etowah River system (Skelton, 2010). In the Cumberland Plateau it occurs from introductions in the Black Warrior River system in Jefferson Co., Alabama. (Bouchard, 1974). In Kentucky, it has a distribution almost identical to Procambarus viaeviridis; known from the floodplains of the extreme lower Tennessee, lower Ohio, and Mississippi Rivers and from tributaries of the Mississippi River in the extreme western portion of the state (Taylor and Schuster, 2004). In Indiana, it was collected in 2000 from Lake Michigan in Indiana and it has spread into the West Branch of the Grand Calamet River (Simon, 2001) and more recently in East Branch Calumet River in Lake Co. (Simon et al., 2005). In Ohio, it was introduced in the western end of Sandusky Bay, a fish hatchery at Denison University, and the Grand River upstream of Harpersfield Dam (Thoma and Jezerinac, 2000). In Missouri, it occurs widely in the Lowland Faunal Region (Pflieger, 1996). In Illinois it is known from lowland habitats in the extreme southern Illinois counties of Alexander, Jackson, massac, Pope, Pulaski, and Union (Page, 1985) and recently the North branch Chicago River in Chicago, Cook Co.; hundreds of km north (Taylor and Tucker, 2005). In Alabama, it is known from the Tennessee, Mobile, Black Warrior, Cahaba, Coosa, Tallapoosa, and Escambia River systems (Schuster and Taylor, 2004) as well as Alabama, Pascagoula, and Tombigbee drainages (Schuster et al., 2008). In Texas, the natural range is throughout the eastern portion along the coastal plain and upstream within rivers thatr flow from the Edwards Plateau into the Gulf (Johnson and Johnson, 2008). This species has been documented in Cuatro Cienegas, Coahuila, Mexico (Dinger et al., 2005).

>1,000,000 individuals

Comments: Circadian as melatonin induces changes in excitability of photoreceptors in the eyestalks of this species (Solorzano-Garcia et al., 1999).

The red swamp crayfish mate in late autumn. Sexes are separate, but 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 (Barnes 1974; Vodopich and Moore 1999; Safra, et al 1999).

Year round breeder, intrapopulational variation of seasonality high & single female may produce >1 brood in a year.

Procambarus clarkii is a large prolific species of crayfish. Characterized by its aggressive burrowing, this speices is well adapted to life even when water levels fluctuate drastically. It is not surprising, that this species survives in very simple, shallow burrows (Jarmon 1999).

US Federal List: no special status

IUCN Red List of Threatened Species: least concern

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Reasons: Native range extends from the Mississippi-Ohio confluence down the Mississippi River floodplain to Louisiana, and along the Gulf coastal Plain southwest to Alabama, to the Rio Grande basin in south New Mexico and north Mexico. It was widely introduced in many places throughout Africa, Asia, and Europe, and also outside its native range in North America.

Environmental Specificity: Broad. Generalist or community with all key requirements common.

Comments: It is an extreme generalist and colonizer. Hypoxia found to reduce survival by 31% and growth by 16% after 12 weeks, and survival by 65% and growth by 90% after 6 weeks (McClain, 1999). Able to survive extensive periods of burrowing, including periods of air exposure, by recovering haemolymph levels rapidly following oxygen depravation and rapid excretion in burrows (McMahon and Stuart, 1999).

Global Short Term Trend: Increase of 10 to >25%

Global Long Term Trend: Increase of >25%

Comments: The red swamp crayfish is a highly invasive species which is under no threat. It is a major threat to other crayfish and to freshwater ecosystems in general. In an anomalous instance, P. acutus replaced P. clarkii in experimental culture ponds in South Carolina in <10 years (Eversole et al., 2006).

Because of the success of commercial aquaculture in its native southern USA, the red swamp crayfish has been introduced to many other areas. Most of these introductions have had negative consequences. Many of these areas have sophisticated irrigation systems in which the crayfish have burrowed. The burrowing activity has damaged the levees, dams, and water control structures. In addition, Procambarus clarkii is an intermediate host for many parasitic helminths of vertebrates, which may create new health problems in areas where the species is successfully established. Because of such adverse effects, many areas introduced to the red swamp crayfish are now trying to eradicate them (Jarmon 1999).

The red swamp crayfish, along with many other species of crayfish are an important source of food for humans. Especially in areas where Cajun communities are common, crayfish are the main ingredient in many everyday meals. Louisiana alone has 48,500+ ha of culture ponds. Procambarus clarkii was introduced to Japan as a food source for bullfrogs, and is now a common family pet all over the main island. This species also appears in many European pet markets. This species is very selective when it comes to its diet. There are many aquatic and semi-aquatic snails that are vectors for human pathogens such as Schistosomiasis. The red swamp crayfish significantly contribute to the control of these snail populations (Barnes 1974; Jarmon 1999).

Comments: Most significant aquaculture crayfish in the world and very significant fishery in LA. Hypoxia found to reduce survival by 31% and growth by 16% after 12 weeks, and survival by 65% and growth by 90% after 6 weeks (McClain, 1999). Able to survive extensive periods of burrowing, including periods of air exposure, by recovering haemolymph levels rapidly following oxygen depravation and rapid excretion in burrows (McMahon and Stuart, 1999).

Comments: Electrophoretic phylogenetic analysis revealed the five southeastern species of teh subgenus Scapulicambarus revealed two cl;ades, one containing P. clarkii and P. troglodytes, and the other containing P. howellae, P. paeninsulanus, and P. okaloosae (Busack, 1989).