This study describes the of distribution and level of endangerment of the genus Gobio in Croatia. Four species of the genus Gobio live in the Croatian Danube River basin: Gobio Gobio - common gudgeon, G. albipinnatus - whitefin gudgeon, G. kesslerii - sand gudgeon and G. uranoscopus - stone gudgeon, while in the Croatian Adriatic Sea basin lives only G. Gobio. According to IUCN methodology and the level of endangerment, in the Red List of Threatened Plants and Animals of Croatia G. Gobio is considered to be of the least concern (LC). G. uranoscopus and G. kesslerii are in the category of near threatened (NT) while G. albipinnatus is considered as data deficient (DD).
The common gudgeon Gobio gobio (L.) has a great phenotypic plasticity being one of the most variable fish species in Europe. In the Iberian Peninsula it has been considered to be an introduced species. However, recent publications have considered that gudgeon populations from different basins of the Iberian Peninsula are native. in this work we tried to clarify the status of Iberian populations by means of molecular methods. thirty-two specimens of common gudgeon from several localities placed in six different Iberian and South French basins (Duero, Ebro, Tajo, Nansa, Bidasoa and Nivelle) were analysed. We reconstructed the phylogenetic relationships between the Iberian gudgeon populations using the whole cytochrome b gene sequence (1141 bp). Moreover, one specimen of G. gobio from the Danube basin and two specimens of Ramanogobio (R. ciscaucasicus and R. uranoscopus) were also included in the study. Our data confirmed the monophyly of the Iberian-French populations analysed and indicated a high genetic differentiation with respect to the common gudgeon populations from Central Europe. However, our results also indicated a very close genetic relationship among the populations of different Iberian basins, showing low genetic distances between them. The absence of population structure among the Iberian populations of G. gobio seems to be due to human activity.