Genetic divergence and connectivity among river and reef spawning groups of walleye (Sander vitreus vitreus) in Lake Erie

Abstract

Discerning population genetic structure is challenging for highly vagile open water animals, as contemporary gene flow may obscure historic phylogeographic patterns. We examined genetic variation among all 10 major river and reef spawning groups of walleye (Sander vitreus vitreus) in Lake Erie for evidence of isolation by distance, segregation by physiographic partitions, and natal site fidelity using 10 nuclear DNA microsatellite loci. Results revealed that although most spawning groups were distinguishable, relationships did not correspond with physiographic basins or distances among localities. Bayesian analyses showed connectivity among some southern shore spawning groups, which included the largest-sized groups. Significant genetic divergence was discerned among walleye spawning in the river systems of eastern Lake Erie, as well as in two sites in western Lake Erie, along with marked isolation from Lake St. Clair. Population structure of Lake Erie walleye thus appears to reflect the interaction of two different intrinsic factors: isolation due to natal site fidelity that maintains patterns of divergence, and connectivity due to individuals that stray from their natal sites to spawn.Résumé : Il n'est pas facile de déterminer la structure génétique de la population chez les animaux très mobiles dans la masse d'eau, car le flux génique actuel peut obscurcir les patrons phylogéographiques du passé. Par l'analyse de 10 locus microsatellites d'ADN nucléaire, nous avons étudiéla variation génétique dans l'ensemble des dix principaux groupes de dorés jaunes (Sander vitreus vitreus) qui fraient dans les rivières et sur les récifs au lac Érié, à la recherche d'indices d'isolement par la distance, de ségrégation par partitions physiographiques et de fidélité au site de naissance. Nos résultats montrent que, bien qu'on puisse reconnaître la plupart des groupes de fraie, leurs relations ne correspondent pas aux bassins hydrographiques, ni aux distances entre les localités. Des analyses bayésiennes révèlent l'existence de connectivité entre certains groupes de fraie de la rive sud, qui incluent les groupes de plus grande taille. Nos données indiquent aussi une divergence génétique significative chez les dorés qui fraient dans les bassins versants de l'est du lac Érié, de même qu'à deux sites dans l'ouest du lac Érié; elles montrent aussi un isolement vis-à-vis le lac StClair. La structure de population des dorés du lac Érié semble donc refléter l'interaction de deux facteurs intrinsèques distincts, l'isolement due à la fidélité au site de naissance qui maintient les patrons de divergence et la connectivité due aux individus qui s'éloignent de leur site de naissance pour se reproduire.[Traduit par la Rédaction] Strange and Stepien 448

Population genetic diversity and phylogeographic divergence patterns of the yellow perch (Perca flavescens)

“…We find less genetic divergence in yellow perch across Lake Erie than in walleye Strange and Stepien, 2007) or smallmouth bass . Both walleye and smallmouth bass had greater genetic diversity in eastern Lake Erie.…”

“…Fine-scale divergence in Lake Erie Stepien and Faber (1998) and Strange and Stepien (2007) postulated that genetic divergence patterns of walleye Sander vitreus spawning groups across Lake Erie were the result of historic recolonization patterns from western (Mississippian) and eastern (Atlantic) glacial refugia, maintained by spawning site philopatry and likely natal homing to spawning sites. We find less genetic divergence in yellow perch across Lake Erie than in walleye Strange and Stepien, 2007) or smallmouth bass .…”

Portfolio theory as a management tool to guide conservation and restoration of multi‐stock fish populations

“…Larval fish from each local spawning area are exported to the open lake, and transported in discrete water masses during the earliest stages of growth (Fraker et al 2015). The spatial and temporal isolation experienced during the early life stages are thought to result in genetically distinct spawning stocks from each area (Merker and v www.esajournals.org Woodruff 1996, Strange and Stepien 2007).…”

Accounting for spatial population structure at scales relevant to life history improves stock assessment: The case for Lake Erie walleye Sander vitreus

“…1). Despite common observations of spawning site fidelity in walleye (Crowe, 1962;Spangler et al, 1977), gene flow does occur at moderate rates in these basins, indicating a single intermixing stock (Strange and Stepien, 2007). The fishery is managed via the Great Lakes Fishery Commission (GLFC) under the auspices of the Joint Strategic Plan for Management of Great Lakes Fisheries (GLFC 1981) with representatives from each member authority (four U.S. states and one Canadian province).…”