: Originated in the pet trade industry. Does not currently exist anywhere in Michigan or in the United States as a wild native population. This species is a prohibited species in the state of Michigan as of April 2020.
: Medium-sized crayfish, ranging from 4-5 in. in length. Marbled color pattern visible on carapace (back). Coloring is usually olive to dark brown but can range from tan to reddish to blue. Claws are slender or narrow.
: Established populations have been found in Germany, Austria, Italy, the Netherlands, United Kingdom, Japan and Madagascar. Can be found in streams, rivers, ditches, ponds, wetlands and retention basins.
: Capable of reproducing by self-cloning; all individuals are female and have the ability to lay up to 700 unfertilized eggs that develop into genetically identical offspring.
Impact and Damage
: Aggressive behavior; they feed on algae, plants, snails, and amphibians and can out-compete native species including fish. Their burrowing can destabilize banks and shorelines.
: Native calico crayfish (Orconectes immunis), which are smaller (2-3.5") and grayish-green in color as well as the native white river crayfish (Procambarus acutus acutus), which is larger and has more rounded claws.
Monitoring and rapid response
: Have not been identified in public waters but were available in the pet trade. Owners of marbled crayfish should humanely dispose of any specimens and avoid flushing them down drains or toilets. Please see RIPPLE for more information.
: The information provided in this factsheet was gathered from the state of Michigan's Invasive Species Profile.
Individual species images that appear with a number in a black box are courtesy of the Bugwood.org network (http://www.invasive.org). Individual photo author credits may not be included due to the small display size of the images and subsequent difficulty of reading the provided text. All other images appear courtesy of Google (http://images.google.com).