Thee species of the genus Gobio occur in the hydrographical network of the Czech Republic, belonging to the basins of three seas (the North, black, and Baltic seas). G. Gobio is distributed over streams belonging to all three sea basins. It is most common in their middle reaches, which are inhabited by fish communities of the Barbus-Chondrostoma type. Compared to that past, the population numbers of this species have not undergone any marked changes. G. kesslerii occurs only in the Bečva River (a tributary to the Morava River) and in the Morava River upstream of the mouth of the Bečva River (danube basin, Black Sea). G. albipinnatus is distributed over the Morava and Dyje rivers and their tributaries (Danube basin, Black Sea). Compared to a century ago, the extent of distribution of G. albipinnatus has dropped to about 50%, which is due chiefly to stream canalisation and water pollution. At present, G. albipinnatus has been ascertained in the lower part of the River Labe, yet there are some doubts as to the originality of this occurrence. The localities of G. albipinnatus and/or G. kesslerii are shared with G. Gobio, with which they hybridise. No evidence is available of the occurrence of G. uranoscopus (Agassiz, 1828) in the Czech Republic, although it does occur in neighbouring Slovakia and Austria. The most important devastation factors, which limited the distribution of the gudgeon in the past, include the construction and operation of dams and weirs, stream canalisation and water pollution. National laws project G. kesslerii as critically endangered and G. albipinnatus as endangered. Both species are listed in European conservation laws (Council Directive no. 92/43/EEC) and, therefore, special areas of conservation have been delimited for them within the NATURA 2000 system.
Seven populations (Oľšava/Hornád R., Oľšava/Topľa R., Ublianka R., Ondava R., Ipeľ R., Malý Dunaj R. and Vlára R.) of Balcan spined loach were subjected to phylogenetic analysis based on variability of the cytochrome b gene and mitochondrial specific marker. They were separated in to five groups but these groups were represented by specimens from different populations. Genetic distances among populations and among groups were quite low. Subsequently, analysis of relations among our groups and sublineages of Danubian-Balkanian complex of Sabanejewia was made. the first four groups were genetically close to sublineage III, while the fifth one to the sublineage IV. These findings agree with the conclusion about conspecificity of analysed Danubian-Dniester populations belonged to monotypic S. balcanica. Phylogenetic analysis showed that the most suitable populations for the restoration of this species in the Bečva River are populations dwelling the Ipeľ and Vlára rivers.
Five species of the genus Gobio have been recorded in Slovenia. G. albipinnatus Lukasch, 1933, G. uranoscopus (Agassiz. 1828), G.Gobio (Linnaeus, 1758) and G. kesslerii Dybowski, 1862 inhabit watercourses of the Danube River in the eastern part of Slovenia (the ecatchments of the Sava, Drava and Mura rivers). G. benacensis (Pollini, 1816 inhabits Adriatic sea basin (the catchment of the Vipava river). The last one was found in Slovenia for the first time in October 2003. In the Red List of Slovenian Freshwater Fishes and Lampreys three species G. albipinnatus, G. uranoscopus and G. kesslerii are classified as vulnerable (V). These species were proposed to be added in Annex II of Council Directive 92/43/EEC.
Almost after a century, the occurrence of Zingel streber (Siebold, 1863) was recorded again in the area of confluence of the rivers Morava and Dyje. The population consisted of fish 0+ to 5+, with 0+ group predominating in the sample, indicating that the species had successfully reproduced in 2003. Analysis was made of their karyotype (n=5) and meristic characters (n=10). The following was the result of a study of growth of standard lengths (n=16): SL1 – 81 mm, SL2 – 114 mm, SL3 – 130 mm, SL4 – 146 mm, SL5 – 166 mm. The biggest individual was a female 5+ of age, TL 200 mm, SL 180 mm. The habitat types preferred by individuals 0+ were the rapidly flowing sections with gravel bottom, in which the stream velocity was 0.2–0.6 m.s-1. Re-occurrence of this species was facilitated by the marked improvement of water quality after 1990 as well as by the barrier-free connection of sections of the rivers Morava and Dyje with the Danube via the Slovakian-Austrian part of the River Morava. Further dispersal of this species is limited by the weir in r.km 26.7 on the Dyje, and six weirs between r.km 74.1 and r.km 101.8 on the Morava. Z. streber is protected by national law and the area mentioned above has been proposed as a pSCI for the NATURA 2000 system.
The genus Gobio in Italy was represented by the endemic species G. benacensis. The original distribution of this species was the Padano-Venetian district, but since a long time it was introduced in central Italy. Introductions of alien species to Italy during the last 10 years brought the sudden introduction of the Danubian G. gobio. Genetic and morphological analyses revealed the extensive presence of G. gobio, which rapidly colonised several rivers in Italy causing the progressive decline of G. benacensis, which now should be considered as an endangered species. Among examined populations those found in the Tagliamento River and transplanted in the Ombrone River represent genetic reservoirs of this species which will probably disappear in northern Italy.