Mediterranean Marine Science Volume 6/2, 2005, 119-146 Alien species on the coasts of Turkey M. e. ÇiNAR1, M. bileceNoĞlu2, b. ÖztÜRK1, T. KATAGAN1 and V. AYSel3 1.Ege University, Faculty of Fisheries, Department of Hydrobiology, 35100 Bornova, Izmir, Turkey 2.Adnan Menderes University, Faculty of Arts & Sciences, Department of Biology, 09010 Aydin, Turkey 3.Onsekiz Mart University, Faculty of Arts & Sciences, Department of Biology, Çanakkale, Turkey e-mail:
[email protected] Abstract The compilation of data on alien species reported from the Turkish coasts yielded a total of 263 species belonging to 11 systematic groups, of which Mollusca had the highest number of species (85 species), followed by Crustacea (51), fishes (43) and phytobenthos (39). The Black Sea is represented by a total of 20 alien species, the Sea of Marmara by 48 species, the Aegean Sea by 98 species and the Levantine Sea by 202 species. The majority of aliens found in the Black Sea and the Sea of Marmara were transported via shipping, whereas the Levantine coast is extensively subjected to Lessepsian migration. Benthic habitats (soft and hard substrata) comprise 76% of the total alien species and the pelagic environment is inhabited by thirty-nine species. Almost 50% of aliens collected from the Turkish coasts were found only at 0-10 m depth. Eight species occur at depths deeper than 100 m. The impacts of aliens on the benthic and pelagic ecosytems are presented. Keywords: Alien species; Species list; Impact; Black Sea; Sea of Marmara; Aegean Sea; Levantine Sea; Turkey. Intoduction capable of colonizing every ecosystem on earth, changing the ecological relations within com- Species introduction is one of the major munities, altering evolutionary processes and factors adversely affecting biological diversity causing dramatic changes in native populations, (ELTON, 1958).