09 August 2021

Lemmer and colleagues, 2020

Lemmers P, Spikmans F, Volk L. 2020. De Marmerkreeft (Procambarus virginalis), een nieuwe invasieve exoot in Limburg. Natuurhistorisch Maandblad 109: 260-266.




In terms of crayfish, the province of Limburg is a province poor in species by Dutch standards. Until 2020, only three invasive alien crayfish species were known. However, Marbled crayfish (Procambarus virginalis) were found at two isolated locations near Venlo within a short period of time in the spring of 2020. The origin and release of one of the populations could be traced via an internet vendor, who had released ten animals in 2017. A dipnet survey in 2020 at this site showed that the density was at least 30.8 specimens per 100 m of embankment. At the other site, length-frequency data suggest the species has been present since 2018. Here, the density was estimated at 5.4 individuals per 100 m of embankment. Further expansion of the populations via overland migration can be expected. It is likely that negative effects on nearby native amphibian populations will occur when no action is taken. The conclusions drawn from this study are that Marbled crayfish (1) are still offered for sale in the aquarium trade even after EU legislation, (2) are actively being released into the wild and (3) are able to establish populations in the Dutch countryside.

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