THE XERCES SOCIETY FOR INVERTEBRATE CONSERVATION

Aquatic Invertebrates in Pacific Northwest Freshwater Wetlands
An Identification Guide and Educational Resource

Procambarus species are introduced to the Pacific Northwest. They are native east of the Rocky Mountains. Of the two species that have been introduced, one has been found throughout the west, while the other has only been found in California. The introductions are probably the result of either released bait or aquarium crayfish. Procambarus is known for it's ability to burrow and withstand drying.

Their tolerance to human disturbance, feeding habits (omnivores), and behaviors are not all too different from the native species, but unlike Pacifastacus, species of Procambarus will have either thumb-like lobes on one of the bottom segments of at least one pair of legs (males) or will have a hard, rounded, raised plate between the last two pairs of legs.

An on-line key to Procambarus is available online from the Carnegie Museum of Natural History Section of Invertebrate Zoology.

Procambarus spp. - crayfish introduced into the Northwest
Procambarus clarkii - (red swamp crayfish - outside link) nonnative invasive, widespread
Procambarus acutus - (white river crayfish - outside link) nonnative invasive, CA