Records of the Atlantic croaker, Micropogonias undulatus, in the Atlantic waters are depicted on the map. White dots indicate native locations of M. undulatus in the western Atlantic Ocean. Red dots indicate previous non-native locations of M. undulatus in the Greater North Sea, while the red triangle marker indicates the location of the M. undulatus recorded in the Gulf of Cadiz during this study (Rota, near the mouth of the Guadalquivir Estuary). White arrows indicate the probable route of arrival through ballast water.