Relationships among mtDNA control region haplotypes of walleye, including A haplotype network from TCS v1.21 [] and B relative frequencies per population sample. Haplotypes from contemporary spawning groups are numbered 1–27 and #28 was found in a historic walleye. Letters = geographic locations of haplotypes from Table 1. * = haplotypes occurring in the historic walleye and “blue pike” samples analyzed here. Circles in the network are sized according to total observed frequency of the haplotype. Lines = a single mutational step between the haplotypes; small unlabeled circles = those hypothesized/not sampled.