The Atlantic–Mediterranean fish assemblage and alien fishes in north-western part of the Black Sea within the waters of Ukraine

Abstract

The article is devoted to alien fish species that have appeared over the last 50 years in coastal waters of the north-western part of the Black Sea (NWBS) within Ukraine. The coastal waters of NWBS are analysed from the northern shore of Karkinitsky Bay (including the Dzharylhach Estuary) to Zmiiny Island in three selected areas: Kinburn–Karkinitsky area (including the Tendra and Yahorlyk estuaries), Odesa area, and Zmiiny Island. A brief description of the Atlantic-Mediterranean fish assemblage of these areas is presented along with that of alien fishes and species that have expanded their geographic range. According to the generalised data from numerous literature sources, from the publication of K. F. Kessler’s work in 1877 until now, 80 species from 63 genera and 43 families belonging to the Atlantic–Mediterranean fish assemblage have been recorded in waters of the NWBS. A complete list of species of this assemblage is given in a table. According to the degree of their occurrence, recently introduced alien fish species of the NWBS are divided into three groups: regular, sporadic, and occasional. Since the 1970s, 7 alien species have been recorded in the NWBS, belonging to 7 genera and 5 families, of which 3 are sporadic (42.9 %) and 4 are occasional (57.1 %). At species level they make up 8.8 % of the representatives of the Atlantic–Mediterranean assemblage represented in waters of the NWBS, whereas 11.1 % at the level of genera and 11.6 % at the level of families. Brief information of these species is given (synonymy, presence of specimens in the fish collection of the National Museum of Natural History NASU and of the Black Sea Biosphere Reserve NASU, brief description, distribution and vector of introduction). Among the alien fish species in the NWBS, representatives of the benthopelagic (4 species, 57.1 %) and pelagic (2 species, 28.6 %) ecological groups prevail. Of the benthic group, only a single species (14.3 %) was noted. It was found that, at present, out of the 7 alien fish species found in waters of the NWBS over the past 50 years, the species whose appearance is associated with the natural process of mediterranisation dominate (4 species, 57.1 %). To date, the vector of introduction cannot be established for three species (42.9 %).