Species that are considered uncertain risk need a more in-depth assessment beyond the Risk Summary to better define the species’ risk to U.S. environments.
Anguilla anguilla, the European Eel, is an eel species native to inland waters of Europe, as well as the Atlantic Ocean and coastal areas from northwestern Russia to North Africa. A. anguilla is used for aquaculture and human consumption, as well as for leather and skins to make fashion accessories. A. anguilla travels great distances to complete its life cycle and has been reported as introduced outside of its native range in multiple countries. It has become established in Turkey, and probably in Iran through natural range expansion. The predominant pathway of introduction outside of Europe and western Asia is through aquaculture escapes. It has been reported as introduced to California, likely through imports for the food industry, but it did not become established there. The importation, sale, or culture of live anguillids is illegal in California. A. anguilla is susceptible to numerous parasites, including the nematode Anguillicolloides crassus that was introduced to Europe from Japan and has had substantial impacts on A. anguilla populations there. A. crassus is not widespread in North America, but more information on transmission of the parasite and its impacts on native eels would be necessary to justify high history of invasiveness. Therefore, history of invasiveness is assessed as “none documented.” A. anguilla has a high climate match with the contiguous United States. This climate match is only valid for the freshwater and brackish life stages of A. anguilla. It does not apply to the marine environments where A. anguilla breed, and thus reduces the ability of this assessment to predict where A. anguilla can establish in the contiguous United States. Further information is needed to assess the invasive potential of this species and suitability of climate in the United States, so the overall risk assessment category is uncertain.