DOI: 10.5061/dryad.nk470
title: Data from: A population genetic window into the past and future of the walleye Sander vitreus: Relation to historic walleye and the extinct “blue pike” S. v. “glaucus”

description: Background: Conserving genetic diversity and local adaptations are
 management priorities for wild populations of exploited species, which
 increasingly are subject to climate change, habitat loss, and pollution.
 These constitute growing concerns for the walleye Sander vitreus, an
 ecologically and economically valuable North American temperate fish with
 large Laurentian Great Lakes' fisheries. This study compares genetic
 diversity and divergence patterns across its widespread native range using
 mitochondrial (mt) DNA control region sequences and nine nuclear DNA
 microsatellite (μsat) loci, examining historic and contemporary
 influences. We analyze the genetic and morphological characters of a
 putative endemic variant– “blue pike” S. v. “glaucus” –described from
 Lakes Erie and Ontario, which became extinct. Walleye with
 turquoise-colored mucus are evaluated, since some have questioned whether
 these are related to the “blue pike”. Results: Walleye populations are
 distinguished by significant considerable genetic divergence (mean FST
 mtDNA=0.32±0.01, μsat=0.13±0.00) and substantial diversity across their
 range (mean heterozygosity mtDNA=0.53±0.02, μsat=0.68±0.03). Southern
 populations markedly differ, possessing unique haplotypes and alleles,
 especially the . The Ohio/New River population that housespossesses the
 most pronounced divergence and the oldest haplotype. Northerly formerly
 glaciated populations have greatest diversity in Lake Erie (mean
 heterozygosity mtDNA=0.79±0.00, μsat=0.72±0.01). Genetic diversity was
 much less in historic Lake Erie samples from 1923–1949 (mean
 heterozygosity mtDNA=0.05±0.01, μsat=0.47±0.06) than today. The historic
 “blue pike” had no unique haplotypes/alleles and there is no evidence that
 it comprised a separate taxon from walleye. Turquoise mucus walleye also
 show no genetic differentiation from other sympatric walleye and no
 correspondence to the “blue pike”. Conclusions: Contemporary walleye
 populations possess high levels of genetic diversity and divergence,
 despite habitat degradation and exploitation. Genetic and previously
 published tagging data indicate that natal homing and spawning site
 philopatry led to population structure. Population patterns were shaped by
 climate change and drainage connections, with northern ones tracing to
 post-glacial recolonization. Southerly populations possess unique alleles
 and may provide an important future genetic reservoir. Allelic frequencies
 of Lake Erie walleye from ~70–90 years ago significantly differed from
 today, suggesting population recovery after extensive habitat loss,
 pollution, and exploitation. The historic “blue pike” was
 indistinguishable from walleye, indicating that taxonomic designation is
 not warranted.
description: HaponskiStepien_mtDNA_alignmentMitochondrial control region sequences of walleye Sander vitreus aligned to other members of the genus Sander.HaponskiStepien_msatdataData for 7 nuclear microsatellite loci for each walleye spawning group across the range, including historic Lake Erie walleye and putative "blue pike" Sander vitreus glaucus