Alien Sipuncula species in the Mediterranean Sea

The compilation of data on alien Sipuncula species reported from the Mediterranean Sea to date yields a total of eight species belonging to four families. Four species have become established in the area, while two species are classified as casual and two as cryptogenic. The pathways of the introduction of alien Sipuncula species were shipping and the Suez Canal. The eastern basin had the higher number of alien Sipuncula species (seven species) mainly due to its proximity to the Suez Canal and dense shipping traffic. Among these species, Aspidosiphon (A.) mexicanus has a wide distributional range in the region, but was considered as a cryptogenic species. The majority of alien Sipuncula species were found on soft subtrata in the region. Brief descriptions of the alien Sipuncula species and their distributional and ecological characteristics are given.