Cooperative Fish and Wildlife Research Units Program: Pennsylvania
Education, Research and Technical Assistance for Managing Our Natural Resources

Pennsylvania Project

Comparative Energetics of Lake Trout Morphotypes

November 2010 - June 2013


Participating Agencies

  • U.S. Fish and Wildlife Service

Lake trout (Salvelinus namaycush) are deep water apex predators native to North America that inhabit glacially formed lakes including the Great Lakes region. During the late 19th century and early to mid-20th century, lake trout populations began to decline throughout the Great Lakes due to lamprey parasitism, overfishing, and poor water conditions. Lake trout management and restoration efforts are focused on stocking and restoring lake trout populations. Lake trout management, however, is complicated by the presence of multiple body forms or morphotypes. The three main morphotypes are lean, humper, and siscowet lake trout which vary in many characteristics, including depth preference, lipid content, body shape, and spawning time. Bioenergetics modeling is often used as tool to guide management decisions using information about the organism’s utilization of habitat (i.e. prey consumed, oxygen usage, etc.). Current lake trout bioenergetics models are based primarily off of the lean morphotype. The main objective of this study is to refine lake trout bioenergetics models to include morphotype variability. A better understanding of potential variability in lake trout morphotype bioenergetics is important for predicting potential future environmental changes on lake trout populations.