Two Decades of Genetic Consistency in a Reproductive Population in the Face of Exploitation: Patterns of Adult and Larval Walleye (Sander vitreus) from Lake Erie's Maumee River

Analysis of genetic consistency in a species exhibiting reproductive fidelity to natal sites may provide an important ecological indicator of its temporal population dynamics, facilitating interpretations of responses to past disturbances and future climate change. The walleye is an ecologically and economically valuable species, whose largest fishery centers in Lake Erie of the Laurentian Great Lakes; it exhibits reproductive site fidelity, despite otherwise wide-ranging dispersal. We test whether its genetic composition and diversity levels have remained temporally stable in Lake Erie’s Maumee River, which is the largest and most highly exploited spawning run. This population has experienced over a century of exploitation, habitat alterations, and pollution, which may have affected genetic structure and might influence future sustainability. Fourteen nuclear DNA microsatellite loci are analyzed from 744 spawning run walleye to test genetic patterns across: (1) years (11; spanning 1995–2013), (2) birth year cohorts, (3) the sexes, and (4) adults vs. larvae. Results indicate stability in genetic diversity levels (mean H_O=0.76±0.03) and allelic composition across years (F_ST<0.001–0.007, NS), cohorts (F_ST<0.001–0.012, NS), sexes (F_ST=0.000, NS), and between larvae and the adults (F_ST=0.003–0.004, NS). This reproductive population thus has maintained genetic stability and high diversity, despite intensive anthropogenic pressures.