Range expansion and habitat preferences of non-native 0+tubenose goby (Proterorhinus semilunaris) in two lowland rivers in the Danube basin

The tubenose goby (Proterorhinus semilunaris) is one of a number of gobiid species currently extending their area of distribution over Europe. We studied inter-annual dynamics and habitat use of 0+ tubenose gobies in the very first years of expansion (1999-2004) in the connected rivers Dyje and Morava (Danube basin). Rapid downstream colonization in the River Dyje (peak in the second year followed by equilibrium) contrasted with slow upstream colonization in the River Morava. 0+ tubenose gobies preferred medium-sized stones (10-30 cm) and avoided fine substrates (silt, sand, gravel). Goby presence also increased in habitats with a larger amount of vegetation or ligneous structures, slower currents, and shallower depths; smallest individuals preferring more homogeneous areas with vegetation and without water currents.