Population dynamics in N. melanostomus and bycatch at three areas (stages) of the invasion.

The sampled rip-rap river stretches (upper Danube River, autumn 2009 to autumn 2011) were assigned to the three sampling areas “IF2010”, “IF2009”, “established area” using the time since invasion (year of first record), with the number of point abundance samples (PAS) and catch data of invasive round goby, barbel Barbus barbus & chub Squalius cephalus (pooled) as most abundant autochthonous fish species and other fish species (rest). The catch (using electrofishing with continuous DC, duration 10s per PAS) is explained as the mean catch per unit effort (CPUE) [PAS−1] and the mean frequency of occurrence (ƒO) [%]. The abbreviation “nd” denotes “not detectable”. Data from the first time of occurrence are shown in bold.