ABSTRACT
The North-Eastern Atlantic and the AtlanticMediterranean Transition In the north-eastern Atlantic, the reduced gobiid fauna of the Atlantic islands is zoogeographically distinct from the mainland gobiid fauna. At these islands a sharp decline in the number of gobiid species is proportional with the distance from the mainland (Fig. 2.2.3, Table 2.2.2). At the present stage of knowledge on species distributions, close relationship of the southern westpart of the Mediterranean with the Gibraltar area is clear, the fi rst area is without the Mediterranean endemics in a narrow sense and all species being present there also inhabit the neighbouring Gibraltar area. However, there is a lack of data on gobiid distribution along the Atlantic coasts and at the southern westpart of the Mediterranean at present. Much more data are necessary for any fi nal conclusion on the Atlantic-Mediterranean transition and on the question if the biogeographical separation of gobies between the Atlantic and the Mediterranean exist near the Strait of Gibraltar, west from the Strait or east from it. Additional data are also necessary for any conclusion about the justifi cation of separate Gibraltar area and on the zoogeographic relationships between the warm temperate Atlantic coasts of Africa and Europe. Th e entire area of the north-eastern Atlantic shows very low level of endemism, with just 6 endemic gobies, two from the Atlantic islands (Didogobius kochi, Mauligobius maderensis), and four with more broad distributions in the temperate North-Eastern Atlantic (Chromogobius britoi, Lebetus scorpioides, Lesueurigobius heterofasciatus, Pomatoschistus lozanoi). A recent immigration of Ponto-Caspian species Neogobius melanostomus happened in the Baltic Sea. Th is highly invasive species was recorded for the fi rst time near the Port of Hel in June 1990, and since than has spread along the coasts of Poland and Germany (Corkum et al., 2004).
