Marmorkrebs are cloning crayfish

“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 are invasive

Marmorkrebs have been introduced 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 banned possession, trade, transport, production, and release of Marmorkrebs (and several other crayfish species) in 2016. The United Kingdom retained this prohibition after its departure from the European Union in 2020.

Japan banned breeding and selling Marmorkrebs (and several other crayfish species) in 2020.

In North America, Marmorkrebs are prohibited in:

In 2022, one person in the US was prosecuted for selling Marmorkrebs and plead guilty.

Marmorkrebs blog

News and commentary here. Featured in The Open Lab 2008 anthology.


Portal for the Marmorkrebs genome is here.

Recent research papers


Brown NEM, Therriault TW. The hidden risk of keystone invaders in Canada: a case study using non-indigenous crayfish. Canadian Journal of Fisheries and Aquatic Sciences: in press.

Gallardo B, Sutherland WJ, Martin P, & Aldridge DC. Applying Fault Tree Analysis to biological invasions identifies optimal targets for effective biosecurity. Journal of Applied Ecology: in press.

2022 research papers

Bohman P, Edsman L, Mrugała A. 2022. Is this a Swedish signal crayfish or an alien marbled crayfish? Crayfish News 44(1): 1, 3-6.

Kaliszewicz A, Karaban K, Sierakowski M, Maciaszek R, Kur M, Pyffel Z, Wolny L, Chmiel K, Łuciuk P, Rusin P, Kowalczyk K. 2022. Effect of dietary supplementation with fatty acids on growth, survival, and fatty acid patterns in Procambarus clarkii and Procambarus virginalis: the first comparison of two invasive crayfish species. The European Zoological Journal 89(1): 123-134.

🆕 🔓 Maciaszek R, Jabłońska A, Prati S, Wróblewski P, Gruszczyńska J, Świderek W. 2022. Marbled crayfish Procambarus virginalis invades a nature reserve: how to stop further introductions? The European Zoological Journal 89(1): 888-901.

🔓 Marn N, Hudina S, Haberle I, Dobrović A, Klanjšček T. 2022. Physiological performance of native and invasive crayfish species in a changing environment: insights from Dynamic Energy Budget models. Conservation Physiology 10(1): coac031.

🆕🔓 Mojžišová M, Svobodová J, Kozubíková-Balcarová E, Štruncová E, Stift R, Bílý M, Kouba A, Petrusek A. 2022. Long-term changes in the prevalence of the crayfish plague pathogen and its genotyping in invasive crayfish species in Czechia. NeoBiota 74: 105–127.

Sentis A, Veselý L, Let M, Musil M, Malinovska V, Kouba A. 2022. Short-term thermal acclimation modulates predator functional response. Ecology and Evolution 12(2): e8631.

🆕 🔓 Tresnakova N, Kubec J, Stara A, Zuskova E, Faggio C, Kouba A, Velisek J. 2022. Chronic toxicity of primary metabolites of chloroacetamide and glyphosate to early life stages of marbled crayfish Procambarus virginalis. Biology 11: 927.

Vogt G. 2022. Studying phenotypic variation and DNA methylation across development, ecology and evolution in the clonal marbled crayfish: a paradigm for investigating epigenotype-phenotype relationships in macro-invertebrates. The Science of Nature 109(1): 16.