# | Species | Year | Period | From - To | Reason | Established in the wild | Ref. no. |
1 | Crangonyx pseudogracilis | 1925-1949 | England or Wales - East Norfolk | ballast water | Unknown | 003224 | |
2 | Watersipora arcuata | unknown | Mexico - Not specified | biofouling | Unknown | 076803 |