Genetic studies Across North America: Total evidence approach - mitochondrial control region - lake comparisons
Population genetic basis for Lake Erie Yellow Perch stock structure and management units
Osvaldo J. Sepulveda Villet and Carol A. Stepien
Abstract: Discerning the genetic basis underlying population structure and its relation to management units (MUs) are critical for effective conservation. Congruency between genetic structure and MUs is essential for interpreting population fluctuations and their ability to withstand and rebound from exploitation and environmental stressors. Our study tests the correspondence between the population genetic structure of Yellow Perch Perca flavescens across Lake Erie to its 4 MUs, which span 2 countries and 5 states/provinces. The Yellow Perch is a key sport and commercial fish whose abundances and distribution center in the lower Great Lakes, and particularly Lake Erie. Lake Erie populations have fluctuated historically due to unstable recruitment patterns and exploitation, and ours is the first fine-scale study using high resolution nuclear microsatellite markers. Fifteen loci are analyzed for 594 spawning individuals from 13 Lake Erie sites, in comparison to outgroups from Lake St. Clair and Lake Ontario. Analyses include pairwise divergence comparisons, AMOVA partitioning, Mantel regression, genetic distance trees, Bayesian assignment, 3-dimensional factorial correspondence, and Monmonier geographic networks. Results show fine-scale genetic structure distinguishing some spawning groups in Lake Erie, with little relationship to the MUs. Further study is needed to further test relationships among mixed stocks, and whether they show any correspondence to MUs.
Figure 1: Map showing our sampling sites in Lakes St. Clair and Erie, with boundaries of Lake Erie management units (MUs 1-4), and physiographic basins. Six most significant barriers to genetic continuity highlighted in red (click on image for larger view).
Figure 2: Three-dimensional factorial correspondence analysis of Yellow Perch microsatellite data from 15 loci, showing clusters of Yellow Perch sampling locations (labeled according to Figure 1).
Figure 3: Mantel pairwise test for relationship between genetic distance (θST/1- θST) and geographical distance (km) among Yellow Perch sampling sites; p = 0.990**, R2 = 0.002, y = 0.000003 (km) + 0.2131.
Figure 4: Estimated population structure for Yellow Perch from Bayesian Structure (Pritchard et al. 2000 2004) analysis for A) K= 6 groups (pp = 0.914) using 15 loci. Optimal K = 6 was determined using ΔK evaluations (Evanno et al. 2005). Individuals are represented by thin vertical lines, which are partitioned into K colored segments that represent the individual’s estimated membership fractions. Black lines separate different samples.
Genetic studies Across North America: Total evidence approach - mitochondrial control region - lake comparisons
