Comparison of performance indicators of N. melanostomus at specimen level.

365 specimens (mean LT = 9.8 cm; SD = 1.2 cm) originating from the investigated sub-populations “IF2010” (invasion front 2010), “IF2009” (invasion front 2009) and “established area” along the upper Danube River (early season 2010 – late season 2011) were sampled for analyses. Numbers of fish dissected, means and corresponding standard deviations (SD) of fecundity and condition indices (gonado-somatic index GSI, Fulton's Condition Factor K, hepato-somatic index HSI), stable isotope signatures (δ15N, δ13C), feeding indices (index of stomach fullness ISF; index of food importance of ephemeroptera, trichoptera and plecoptera IFI (EPT)) and prey-specific indices (catch per unit effort CPUE (EPT) and index of environmental importance of ephemeroptera, trichoptera and plecoptera IEI (EPT)) and parasite infection indices were calculated for females and males. Values highlighted in bold denote significant differences (Mann-Whitney U test) between sexes. Superscript letters denote significant differences (Kruskal-Wallis test) between populations with p-values encoded by asterisks (*denotes p≤0.05; ** denotes p