Procambarus clarkii (Red swamp crawfish)

Animal Crustaceans
Family: Cambaridae
Classification: Prohibited

Red swamp crayfish are native to South central United States, where they are also grown commercially. Because of the success of commercial aquaculture in its native range, the red swamp crayfish has been introduced to many other areas. They are also popular as a bait species for largemouth bass, which is thought to be the most likely path of introduction into Washington. Adults of this species are about 2.2 to 4.7 inches in length. Although most crayfish species are herbivores, some studies indicate that the red swamp crayfish also eats insect larvae, tadpoles, and snails. In California they preyed upon young California newts.

The behavior most characteristic of the red swamp crayfish is burrowing to find moisture, food, warmth, and for protection during the molting process. The burrowing activity has damaged levees, dams, and water control structures in some areas where they have been introduced. 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.

Populations have become established in California, Idaho and Oregon. In September of 2000, three red swamp crayfish were captured during a routine survey. This was the first official record of the species in Washington. They have now been found in other lakes in King County. We do not know what the impacts of their introduction will be. In most areas where populations have become established there have been enough negative impacts that eradication efforts are being made. We wish to stop any further introductions in Washington. People may capture prohibited species, but must not place them back into the water, and must kill them before they leave the area.

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