Morphology of the Common Gudgeon, Gobio Gobio (L.) Sensu Lato, from the Vistula River Drainage in the Context of Recent Literature Data (Teleostei: Cyprinidae)

The common gudgeon Gobio gobio (L.) is considered to be highly variable and to show very good adaptability to local environmental conditions. The most recent studies show that the traditional notion of the G. gobio species covers a number of highly similar but distinct species that can be distinguished based on detailed analysis of morphometric characters. This work presents the results of biometric studies on common gudgeons from two small rivers in the Vistula River drainage. The study has shown several biometric differences between the analyzed populations. Whether the two populations of the common gudgeon represent distinct species or are only evidence of intraspecific variation will be clear once the required comparative material has been gathered. Therefore, in accordance with the international trend, these populations should be treated as Gobio gobio (L.) sensu lato (= G. gobio (L.) complex).