Date of Award
Carl Ruetz III
Habitat heterogeneity has the possibility of structuring populations. Even in connected landscapes, there can be cryptic structuring of populations that coincides with landscape features that limit gene flow or select for different phenotypes within a species. Yellow perch (Perca flavescens) is an economically and ecologically prominent fish in the Laurentian Great Lakes. In the Lake Michigan basin, yellow perch reside in nearshore Lake Michigan, including drowned river mouths (DRMs, lake-like habitats that link tributaries to Lake Michigan). The goal of this study was to understand whether yellow perch populations are structured in eastern Lake Michigan by the connected DRM lake habitats. Specifically, I tested whether DRMs and Lake Michigan are distinct genetic stocks of yellow perch and which habitats those stocks occur in throughout the year. To do so, I genotyped yellow perch at 14 microsatellite loci collected from 10 DRMs in both deep and littoral habitats during spring, summer, and fall and two nearshore sites in Lake Michigan (spring and fall) during 2015-2016. I found that all DRMs are genetically distinct from nearshore Lake Michigan. My data also suggest that Lake Michigan yellow perch likely use DRM deep habitats during the fall season, based on how deep-habitat DRM yellow perch from fall cluster with Lake Michigan yellow perch. I also found weak but significant genetic structuring between DRMs. These results are consistent with previous studies and angler accounts of yellow perch. Fisheries managers should take into account this population structure when setting fishing regulations in DRM systems.
Chorak, Gregory M., "Yellow Perch Genetic Stock Structure in Eastern Lake Michigan: What is the Importance of Drowned River Mouth Lakes?" (2017). Masters Theses. 856.