Researchers from the Ciências da Universidade de Lisboa, Portugal led by Maria Cruz and Rui Rebelo
have found that Procambarus clarkii, or the red swamp crayfish, introduced in the 1970′s to the Iberian peninsula is still well established today. Originally from the southern United States of America, the red swamp crayfish has been found to establish itself on every continent except Antarctica and Australia and has been noted for its severe detrimental effects on rice production on the Iberian Peninsula.
Cruz and Rebelo found that with the red swamp crayfish, its range was mostly determined by geographical features. However, they also found that the red swamp crayfish frequently experiences overland transfer between bodies of water, making it an extremely mobile aquatic species. With this said, Cruz and Rebelo both predict a continued spread to red swamp crayfish to currently unpopulated bodies of water in the region.
Reference: Hydrobiologia, Volume 575, Pages 191-201, Published OCT 2006, DOI: 10.1007/s10750-006-0376-9