The spread of the parthenogenetic marbled crayfish, Marmorkrebs

The parthenogenetic marbled crayfish Marmorkrebs was discovered in the pet trade in Europe in the 1990s. Since then, its distribution through the pet trade has spread from Europe to other continents, including North America. North American pet owners were surveyed online with the aims of trying to track when Marmorkrebs entered the North American pet trade, the ways in which it spread through the pet trade, and how widely distributed Marmorkrebs are throughout the continent. Marmorkrebs have been in the North American pet trade since at least 2004, with the number of people increasing every year. While many Marmorkrebs are sold through online sources, face-to-face personal contacts account for almost as many acquisitions. The increasing spread of Marmorkrebs through the pet trade increases the probability that Marmorkrebs will be released into North American ecosystems. Key words: crustacean, aquaria, hobbyists Marmorkrebs are an entirely female lineage of crayfish that reproduces by parthenogenesis (Scholtz et al. 2003; Martin et al. 2007). Marmorkrebs appear to be closely related to Procambarus species in the southeastern Unite