Indiana Biological Survey

Division of Crustaceans Projects

Nonindigenous Crayfish

Louisiana red swamp crayfish Procambarus (Girardelli) clarkii

Rusty crayfish Orconectes rusticus

The invasion of nonindigenous crayfish has been one of the greatest threats to native crayfish species globally. With more that 80% of native North American crayfish restricted to a single watershed, the reduction of population numbers and ultimately the destruction of reproductive populations through either competition, hybridization, or predation is a considerable threat. Two invasive species have been a problem within Indiana. The rusty crayfish Orconectes (Procericambarus) rusticus and the Louisiana red swamp crayfish Procambarus (Girardelli) clarkii are among the most invasive and destructive species.

The difference between exotic and nonidigenous classifications is dependent on the native range of a species. For example, when an organism is classified as exotic, this usually means that it is normally not from any contiguous watershed or continent.

The rusty crayfish was historically found in the Whitewater and Maumee River watersheds of Indiana. The species is still common in each of these drainages; however, as a result of the species large size it has been used extensively in the bait industry. Well meaning anglers have unintentionally transferred this species into other watersheds. The transfer of Orconectes rusticus has caused a significant decline in native crayfish species populations and aquatic plant communities in Wisconsin, Illinois, Ohio, Indiana, and Michigan.

The Lousiana Red Swamp Crayfish is native to the Coastal Plain. Historically, the species was found in extreme southwest Indiana. The species has found a market in the aquarium trade as "freshwater lobster". The species bright red coloration is a beautiful addition to the native community aquarium; however, as the species grows in size it becomes extremely aggressive and will become predatory to community fish. We have begun collecting the species in coastal wetlands of the Great Lakes from tributaries of Lake Michigan. The specimens we have collected have been found from the Dead River (Illinois) to the Grand Calumet River (Indiana) in southern Lake Michigan. Additional specimen records have been collected from the North Branch of the Chicago River. It seems that the species is probably being intentionally released into the environment by well-meaning aquarists or they are being flushed down toilets and are able to tolerate the wastewater treatment plant process. Additional Great Lakes records include the Sandusky area of Lake Erie. There seems to be a correlation between the presence of this species with urban areas around wastewater treatment plants.

Management issues: The movement of rusty crayfish has become a management issue since the reduction of aquatic plants in lakes causes a reduction in habitat for young fish. Likewise, the release of Louisiana red swamp crayfish is problematic since the species is aggressive and also is destructive of native aquatic plants.