Truss Type Morphometric Comparison of Lake Trout From Elk Lake (Antrim County), Lean Forms From Lake Superior, and Stocked Lean Forms From Lake Michigan

Elk Lake is a small inland lake located in Antrim County, Michigan. It was hydrologically separated from Lake Michigan during the mid 19^th century and contains a self-sustaining population of lake trout (Salvelinus namaycush). Assessments in 2011-2012 indicate that lake trout in Elk Lake are occupying deep water when spawning, similar to native forms of lake trout no longer found in the Great Lakes. The objectives of this study were to determine if the Elk Lake lake trout are morphologically different than lean forms of lake trout in Lake Superior and stocked forms in Lake Michigan. Sampling in Elk Lake consisted of gill netting in deep water (80-200 feet) during Fall 2011 and 2012, and Spring 2012. A truss-type morphometric analysis was used to compare the Elk Lake, Lake Michigan, and Lake Superior populations. Results for the truss analysis indicated distinct morphological differences between the three populations, which is supported by genetic analysis differentiating Elk Lake forms from stocked forms in Lake Michigan and lean forms in Lake Superior.