Short description of Procambarus fallax f. virginalis, Marbled Crayfish

The marbled crayfish is a medium sized crayfish of up to 13 cm but often less than 10 cm body length. It has small claws and a variable colour pattern from bluish tinged to brightly blue.

Impact summary: Procambarus fallax f. virginalis, Marbled Crayfish

The species’ ecology and interactions with native species are insufficiently understood and its impact in European habitats has yet to be assessed. However, it is known to consume a broad range of plants and invertebrates, thus posing a risk to native ecosystems if released to natural waters

Habitat summary: Procambarus fallax f. virginalis, Marbled Crayfish

Marbled crayfish are presumably able to colonise lentic habitats in most parts of Central Europe, so there is a concern that this alien species will become established in GB if released.

Overview table

Environment	Freshwater
Species status	Non-Native
Native range	Southeastern U.S.A.
Functional type	Omnivore
Status in England	Non-Native
Status in Scotland	Non-Native
Status in Wales	Non-Native
Location of first record
Date of first record	Unknown

Origin

Molecular analyses suggest that the Marbled crayfish is the parthenogenetic form of Procambarus fallax, which is why the tentative scientific name Procambarus fallax f. virginalis has been proposed. As P. fallax occurs in southern Georgia and Florida, it is assumed that the Marbled crayfish originates from the southeastern United States. However, an indigenous population of the parthenogenetic form has never been reported, so that there currently is no known native founder population of Marbled crayfish.

First Record

No records from GB to date.

Pathway and Method

It was first discovered in the German aquarium trade in the mid 1990s and has since been introduced by people into natural ecosystems. Whether these introductions were deliberate or accidental is unclear. There is concern that its spread in the pet trade will inevitably also result in releases from captivity.

Species Status

Over the last decade, it has been found in natural ecosystems in Germany, the Netherlands, Italy, Madagascar and Japan. Although most reports in the wild in Europe consisted of only single individuals, this crayfish has successfully established populations in Madagascar (2009) and Germany (2010). As it is rapidly expanding in Madagascar, there is great concern that these introductions could result in it becoming an invasive non-native species in Europe

Dispersal Mechanisms

The increasing availability of Marbled crayfish through the pet trade increases the probability of it being released into natural ecosystems.

Reproduction

It is the first recorded crayfish capable of asexual reproduction (parthenogenesis) and unique in that there exist only females which produce genetically identical offspring. An adult is capable of producing up to 270 eggs every 8–9 weeks with maturity being reached 25–35 weeks after hatching, under optimum conditions. Its presumed sexual form, Procambarus fallax, can reproduce year round.

Known Predators/Herbivores

None known.

Resistant Stages

None known.

Habitat Occupied in GB

Not currently recorded in GB.

Although there are no records from the wild in GB so far, it has been found in freshwaters of Germany, the Netherlands, Italy, Madagascar and Japan. The only known established population in Europe is that from a small lake in the Upper Rhine catchment, Germany.

Environmental Impact

The species is considered to be a serious future threat to aquatic biodiversity in regions where it becomes established as one single specimen is sufficient to create a new population and previous introductions of other non-native crayfish species have had profound ecological impacts. What is more, to maintain their high breeding output, they are voracious feeders and consume a broad range of aquatic plants and invertebrates. This poses a risk that they may have a direct impact on native aquatic fauna and flora if released to natural waters. Its potential competitive ability against native European crayfish species has been shown in a small lake in the Upper Rhine catchment, where the species was detected in 2010 and has quickly become the prevalent crayfish species.

Health and Social Impact

None known.

Economic Impact

None known.

Identification

Martin, P., Dorn, N.J., Kawai, T., van der Heiden, C., Scholtz, G. (2010) The enigmatic Marmorkrebs (marbled crayfish) is the parthenogenetic form of Procambarus fallax (Hagen, 1870). Contributions to Zoology, 79, 107-118.

Biology, ecology, spread, vectors

Chucholl, C., Pfeiffer, M. (2010) First evidence for an established Marmorkrebs (Decapoda, Astacida, Cambaridae) population in Southwestern Germany, in syntopic occurrence with Orconectes limosus (Rafinesque, 1817). Aquatic Invasions, 5, 405-412.

Faulkes, Z. (2010) The spread of the parthenogenetic marbled crayfish, Marmorkrebs (Procambarus sp.), in the North American pet trade. Aquatic Invasions, 5, 447-450.

Jones, J.P.G., Rasamy, J.R., Harvey, A., Toon, A., Oidtmann, B., Randrianarison, M.H., Raminosoa, N., Ravoahangimalala, O.R. (2009) The perfect invader: a parthenogenic crayfish poses a new threat to Madagascar's freshwater biodiversity. Biological Invasions, 11, 1475-1482.

Martin, P., Shen, H., Fuellner, G., Scholtz, G. (2010) The first record of the parthenogenetic Marmorkrebs (Decapoda, Astacida, Cambaridae) in the wild in Saxony (Germany) raises the question of its actual threat to European freshwater ecosystems. Aquatic Invasions, 5, 397-403.

Scholtz, G., Braband, A., Tolley, L., Reimann, A., Mittmann, B., Lukhaup, C., Steuerwald, F., Vogt, G. (2003) Ecology - Parthenogenesis in an outsider crayfish. Nature, 421, 806-806.

Management and impact

Robbins, M. (2009) Owning clones. Tropical Fish Hobbyist, 57, 72–74.

Feria, T.P., Faulkes, Z. (2011) Forecasting the distribution of Marmorkrebs, a parthenogenetic crayfish with high invasive potential, in Madagascar, Europe, and North America. Aquatic Invasions, 6, 55-67.

General

https://www.cabi.org/isc/datasheet/110477

https://secure.fera.defra.gov.uk/nonnativespecies/downloadDocument.cfm?id=620