The network of COI haplotypes that includes A. astacus haplotypes from Albanian localities (Ohrid Lake and Devolli River, both Adriatic Sea basin; obtained in the present study) and from five sea basins: Adriatic Sea (Croatia, Montenegro), Aegean Sea (Kosovo), Black Sea (Austria, Bulgaria, Croatia, Germany, Hungary, Romania), Baltic Sea (Germany, Poland), North Sea (Belgium, Czech Republic, Germany; published in Schrimpf et al., 2011, 2014). The size of the circles is proportional to the frequency of the represented haplotypes at the country level in all five sea basins. Only two haplotypes from Albania are presented (from Ohrid Lake and Devolli River); due to the shorter length of the published A. astacus sequences (350 base pairs [bp]) the diversity of haplotypes from the Devolli River was lost (based on full length 635 bp, three haplotypes were found). The white dots indicate the median vectors. The number of base pair changes is given (no number indicates a change of 1 bp). The details on the haplotypes published in Schrimpf et al. (2011, 2014) are provided as a Supplementary Material.