Temporal abundance data for the Chinese mitten crab by region. Regions are either major rivers and the coastal area they drain into, or countries if crabs are predominantly coastal or inhabit several small river systems. Black solid lines indicate the presence of the Chinese mitten crab but without knowledge of its abundance, dashed black lines indicate that the Chinese mitten crab has not been reported in the respective time frame. No line indicates a lack of data, which is highlighted by a question mark. Colored dots indicate single years with few recorded crabs, and thin colored lines indicate continuous annual records of few crabs. Thicker colored lines indicate an increase in abundance, as discussed in the Suppl. material 2.