Non-native distribution of the Chinese mitten crab. Each dot is a record (GBIF.org 2021; Ojaveer et al. 2007; Shakirova et al. 2007; Dittel and Epifanio 2009; Veilleux and Lafontaine 2009; Petrescu et al. 2010; Naser et al. 2012). A: European distribution; B: North American distribution. Closed black dots: records of crabs collected after 2000 in GBIF and literature records, open dots: GBIF records prior to 2000. Colored areas are regions with abundant reports of the Chinese mitten crab shown in Figure 1 and detailed in the Suppl. material 2. The shape of the colored regions was chosen to include all reports from an area, but does not reflect the exact range of the Chinese mitten crab. Regions with a black outline represent established populations. The Baltic Sea region is a special case (dashed outline), as it is unclear if this region should be considered an independent population or if it is an extension of North Sea populations. Mitten crabs from the Persian Gulf are Eriocheir hepuensis. A single observation of Eriocheir japonica has been reported from the west coast of the United States in the state of Oregon.