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Adult Marmorkrebs

What are Marmorkrebs?

“Marmorkrebs” is an informal name given to marbled crayfish that were discovered by hobbyists in Germany in the late 1990s. “Marmorkrebs” roughly translates from German as “marbled crab.” The scientific name for Marmorkrebs is Procambarus virginalis (previously Procambarus fallax f. virginalis). They are an asexual relative of slough crayfish (Procambarus fallax) that live across Florida and southern Georgia in the United States. The only known cases of Marmorkrebs in the wild are where they have been introduced by humans.

Marmorkrebs are parthenogenetic: they are all females, and reproduce without sex. This is the only decapod crustacean found that reproduces only this way, giving it incredible potential as a model organism for research. Some of the advantages of Marmorkrebs are that they are genetically identical, reproduce at high rates, and are easy to care for.

Marmorkrebs as invasive species

Marmorkrebs have been introducted in many countries, and have established populations in some. They can damage agriculture and threaten native species. Marmorkrebs should not be used for bait (see here), kept in outdoor tanks or ponds (Marmorkrebs can migrate over land; see here), or placed in any other situation where they could be released into natural ecosystems.

The European Union possession, trade, transport, production, and release of Marmorkrebs (and several other crayfish species) in 2016. Japan similarly banned breeding and selling Marmorkrebs (and several other crayfish species) in 2020. Marmorkrebs are also prohibited in several North American jurisdictions.

Country Jurisdiction Year prohibited
Canada Saskatchewan 2020
USA Idaho 2010
  Michigan 2020
  Missouri 2011
  Tennessee 2015

Map of Marmorkrebs introductions

View Marmorkrebs introductions in a larger map


Timeline of key mooments in Marmorkrebs reseach and policy is here.

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The portal for the complete Marmorkrebs genome is at

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Recent research papers

For comprehensive list of past research papers, click here.


NewOpen Access Grandjean F, Collas M, Uriarte M, Rousset M. First record of a marbled crayfish Procambarus virginalis (Lyko, 2017) population in France. BioInvasions Records 10: in press.

NewOpen Access Scheers K, Brys R, Abeel T, Halfmaerten D, Neyrinck S, Adriaens T. The invasive parthenogenetic marbled crayfish Procambarus virginalis Lyko, 2017 gets foothold in Belgium. BioInvasions Records 10: in press.

Stara A, Zuskova E, Vesely L, Kouba A, Velisek J. Single and combined effects of thiacloprid concentration, exposure duration, and water temperature on marbled crayfish Procambarus virginalis. Chemosphere: in press.

2021 research papers

Hossain MS, Kubec J, Guo W, Roje S, Ložek F, Grabicová K, Randák T, Kouba A, Buric M. 2021. A combination of six psychoactive pharmaceuticals at environmental concentrations alter the locomotory behavior of clonal marbled crayfish. Science of The Total Environment 751: 141383.

Maiakovska O, Andriantsoa R, Tönges S, Legrand C, Gutekunst J, Hanna K, Pârvulescu L, Novitsky R, Weiperth A, Sciberras A, Deidun A, Ercoli F, Kouba A, Lyko F. 2021. Genome analysis of the monoclonal marbled crayfish reveals genetic separation over a short evolutionary timescale. Communications Biology 4(1): 74.

New Okada S, Hirano N, Abe T, Nagayama T. 2021. Aversive operant conditioning alters the phototactic orientation of the marbled crayfish. The Journal of Experimental Biology 224(6): jeb242180.

Open Access van Kuijk T, Biesmeijer JC, van der Hoorn BB, Verdonschot PFM. 2021. Functional traits explain crayfish invasive success in the Netherlands. Scientific Reports 11(1): 2772.

Veselý L, Ruokonen TJ, Weiperth A, Kubec J, Szajbert B, Guo W, Ercoli F, Bláha M, Buric M, Hämäläinen H, Kouba A. 2021. Trophic niches of three sympatric invasive crayfish of EU concern. Hydrobiologia 848(3): 727–737.

Vogt G. 2021. Evaluation of the suitability of the parthenogenetic marbled crayfish for aquaculture: potential benefits versus conservation concerns. Hydrobiologia 848: 285–298.

2020 research papers

Open Access Andriantsoa R, Jones JPG, Achimescu V, Randrianarison H, Raselimanana M, Andriatsitohaina M, Rasamy J, Lyko F. 2020. Perceived socio-economic impacts of the marbled crayfish invasion in Madagascar. PLOS ONE 15(4): e0231773.

Benson AM. 2020. Identification of innexins contributing to giant-fiber escape responses in marbled crayfish. Master's thesis, School of Biological Sciences, Illinois State University. Stein W, Vidal-Gadea A, advisors.

Hossain MS, Guo W, Martens A, Adámek Z, Kouba A, Buric M. Potential of marbled crayfish Procambarus virginalis to supplant invasive Faxonius immunis. Aquatic Ecology 54: 45-56.

Kawai T, Patoka J. 2020. Morphology of gastric mills and mandibles of New Guinean parastacid crayfishes, with comparisons with other Astacidea (Decapoda). Journal of Crustacean Biology 40(6): 692-703.

Open Access Laurenz J, Brendelberger H, Lehmann K. 2020. Effects of Diclofenac on the embryonic development of freshwater crayfish. International Aquatic Research 12(4): 255-265.,

Open Access Laurenz J, Georg A, Brendelberger H, Lehmann K. 2020. Effects of nitrate on early life stages of Astacus astacus (Linnaeus, 1758) and Procambarus virginalis (Lyko, 2017). International Aquatic Research 12(1): 53-62.

Open Access Laurenz J, Lietz L, Brendelberger H, Lehmann K, Georg A. 2020. Noble crayfish are more sensitive to terbuthylazine than parthenogenetic marbled crayfish. Water, Air, & Soil Pollution 231: 548.

Open Access Linzmaier SM, Jeschke JM. 2020. Towards a mechanistic understanding of individual-level functional responses: Invasive crayfish as model organisms. Freshwater Biology 64(4): 657-673.

Linzmaier SM, Musseau C, Matern S, Jeschke JM. Trophic ecology of invasive marbled and spiny-cheek crayfish populations. Biological Invasions 22: 3339–3356.

Lyko F. 2020. Epigenetic adaptation in a clonal invasive crayfish. Symposium presentation at Society for Integrative and Comparative Biology, 3-7 January 2020, Austin, Texas, USA. (Abstract only.)

Roje S, Švagrová K, Veselý L, Sentis A, Kouba A, Buric M. 2020. Pilferer, murderer of innocents or prey? The potential impact of killer shrimp (Dikerogammarus villosus) on crayfish. Aquatic Sciences 83(1): 5.

Open Access Rusch JC, Mojžišová M, Strand DA, Svobodová J, Vrĺlstad T, Petrusek A. 2020. Simultaneous detection of native and invasive crayfish and Aphanomyces astaci from environmental DNA samples in a wide range of habitats in Central Europe. NeoBiota 58: 1-32.

New Open Access Son MO, Morhun H, Novitskyi RO, Sidorovskyi S, Kulyk M, Utevsky S. 2020. Occurrence of two exotic decapods, Macrobrachium nipponense (de Haan, 1849) and Procambarus virginalis Lyko, 2017, in Ukrainian waters. Knowledge and Management of Aquatic Ecosystems 421: 40.

Stein W, Talasu S, Vidal-Gadea A, DeMaegd ML. 2020. Physiologists turned Geneticists: Identifying transcripts and genes for neuronal function in the marbled crayfish, Procambarus virginalis. The Journal of Undergraduate Neuroscience Education 19(1): A36-A51.

New Talasu S. 2020. Identifying dopamine receptor genes and transcription marbled crayfish. Poster presentation given to Illinois Mathematics and Science Academy, 22 April 2020. (Abstract only.)

Open Access Tönges S, Masagounder K, Gutekunst J, Lohbeck J, Miller AK, Böhl F, Lyko F. 2020. Physiological properties and tailored feeds to support aquaculture of marbled crayfish in closed systems. bioRxiv: 2020.2002.2025.964114. (Unreviewed preprint)

Open Access Velisek J, Stara A, Kubec J, Zuskova E, Buric M, Kouba A. 2020. Effects of metazachlor and its major metabolite metazachlor OA on early life stages of marbled crayfish. Scientific Reports 10(1): 875.

Velisek J, Stara A, Zuskova E, Chabera J, Kubec J, Buric M, Kouba A. 2020. Effects of chloridazon on early life stages of marbled crayfish. Chemosphere 257: 127189.

Vogt G. 2020. Biology, ecology, evolution, systematics and utilization of the parthenogenetic marbled crayfish, Procambarus virginalis. In: Ribeiro FB (ed.), Crayfish: Evolution, Habitat and Conservation Strategies, pp. 137-227. Nova Publishers: Hauppauge.

New Open Access Weiperth A, Bláha M, Szajbert B, Sepros R, Bányai Z, Patoka J, Kouba A. 2020. Hungary: a European hotspot of non-native crayfish biodiversity. Knowledge and Management of Aquatic Ecosystems 421: 43.

Yonvitner Y, Patoka J, Yuliana E, Bohatá L, Tricarico E, Karella T, Kouba A, Reynolds JD. Enigmatic hotspot of crayfish diversity at risk: Invasive potential of non-indigenous crayfish if introduced to New Guinea. Aquatic Conservation: Marine and Freshwater Ecosystems: 30(2): 219-224.

Popular press

Tropical Fish Hobbyist March 2009 cover New Scientist issue 3185 cover

Anonymous. 2007. British crayfish could be wiped out by alien species with the plague. The Daily Mail. 28 June 2007.

Anonymous. 2016. Cangrejo mármol, una curiosa especie invasora con dos caras. Real Jardín Botánico press release. 8 September 2016.

Anonymous. 2020. This self-cloning crayfish is scuttling into rivers and streams throughout Alberta. CBC News Calgary. 22 April 2020.

Cepelewicz J. 2020. Nature versus nurture? Add ‘noise’ to the debate. Quanta Magazine. 23 March 2020.

Coghlan A. 2003. Crayfish clones poised to invade European waters. New Scientist 2383 (22 February 2003).

Estonian Research Council. 2018. The marbled crayfish have established themselves in Narva power plant. EurekAlert!

Faulkes Z. 2009. How Marmorkrebs can make the world a better place. In: Rohn J (ed.), Grant RP (deputy ed.), Zivkovic B (series ed.), The Open Laboratory: The Best In Science Writing On Blogs 2008, pp. 86-87. Coturnix: Chapel Hill.
Original post:

Faulkes Z. 2011. The decade the clones came. In: Goldman JG (ed.), Zivkovic B (series ed.), The Open Laboratory: The Best of Science Writing on the Web 2010, pp. 151-156. Coturnix: Chapel Hill.
Original post:

Fujiie H. 2017. War urged to destroy alien cloning mystery crayfish. The Asahi Shimbun (Japanese newspaper) news story. 13 April 2017.

Gerety RM. 2021. Stowaways. Harper's 342(2049): 72-79.

German Cancer Research Center. 2015. A cray-active solution for cancer research.

Heimer K. 2010. Invasion of self-cloning crayfish alarms Madagascar. Deutsche Presse-Agentur wire story.,alarms-madagascar-feature.html

Horton J. 2013. Scots wildlife at risk from alien crayfish breeds. The Scotsman. 21 April 2013.

Le Page M. 2018. Crayfish clone army on the loose. New Scientist 239(3185): 16. (Published online with title, “Freak accident created a massive army of super-fertile clones.”)

Linzmaier S. 2016. Vom Aquarium in den See. Verbundjournal 106: 14-15.

Löwe K. 2010. Gefahr aus dem Aquarium. Mitteldeutsche Zeitung (Central German Newspaper) news story. 13 October 2010.

Pennisi E. 2015. Crayfish create a new species of female ‘superclones’. Science News ScienceShots.

Privenau K. 2010. Marmorkrebs bringt Pest. Mitteldeutsche Zeitung (Central German Newspaper) news story. 12 October 2010.

Robbins M. 2009. Owning clones. Tropical Fish Hobbyist 57(7): 72-74.

Swedish Agency for Marine and Water Management. 2012. Discovery of marbled crayfish creates concern.

Swedish Agency for Marine and Water Management. 2013. First analysis of marbled crayfish completed.

Zhang S. 2018. A pet crayfish can clone itself, and it’s spreading around the world. The Atlantic

Zimmer C. 2018. This mutant crayfish clones itself, and it’s taking over Europe. The New York Times


Idaho designated Marmorkebs an aquative invasive invertrbrate species in 2010, which makes possessing or transporting them illegal. Missouri has added Marmorkrebs to its prohibited species list, effective 1 March 2011. Read more here. Tennessee designated Marmorkrebs as “Class V wildlife,” meaning they can only be kept by zoos, effective October 2015. Read more here and here.

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This site maintained by Zen Faulkes. Last updated 29 March 2021. Happy Holi, April Fool's, and Easter. Don't believe everything you read.