Home – Home – Jornals – Contemporary Problems of Ecology 2022 number 1

The round goby is a small demersal fish considered one of the top invasive fish species. Having settled far beyond its native Ponto-Caspian region, the round goby currently inhabit the basins of the Baltic and North Seas, as well as the Great Lakes of North America. Since 2005, the species has been increasingly occurred in the eastern part of the Baltic Sea - the Gulf of Finland, where one of its northernmost populations was founded. The study is focused on studying the morphological differentiation of the round goby from geographically distant parts of the Gulf of Finland in order to assess the heterogeneity of this population and to suggest the most probable ways of the species penetration and dispersal there. Four samples were compared in 5 meristic and 35 morphometric traits. The traits characterized the number of finrays and rows of scales along the body, the shape of the body and head, and the position and shape of the fins. The comparison was carried out using indices, parametric and nonparametric tests, factorial, cluster analysis and multivariate scaling. Round goby samples collected at a distance of 40 to 270 km significantly differed in body shape, position and size of fins, while other characters were less prominently different between locations. The round goby from the western part of the gulf was the most different from goby of its eastern part, where morphological differentiation between locations was also observed. The results of the study assume the existence of separate round goby populations in the Gulf of Finland, with development of morphological features, associated with local habitat conditions, and the limited migrations of the species within the gulf. On the basis of the results obtained, we suggested independent introduction of the round goby into the western and eastern parts of the Gulf of Finland of the Baltic Sea.