**The title, authors, and abstract for this completion report are provided below.  For a copy of the completion report, please contact the GLFC via e-mail or via telephone at 734-662-3209**

�

Morphological and Life History Variation with Depth in an Introduced Lake Trout Population

Craig P. Stafford¹, Megan V. McPhee², Lisa A. Eby¹, Fred W. Allendorf³

¹ College of Forestry and Conservation, University of Montana, 32 Campus Drive, Missoula, MT 59812

² Flathead Lake Biological Station, �University of Montana, 32125 Bio Station Lane, Polson, MT 59860

³ Division of Biological Sciences, �University of Montana, 32 Campus Drive, Missoula, Montana 59812

June 2009

ABSTRACT:

We compared stable isotopes, diets, life history patterns, morphologies, lipids, and microsatellite genotypes between shallow and deep captured lake trout in an introduced population. �Isotopic signatures demonstrated that the depth fish were captured (shallow and deep) indicate a longer term depth bias in distribution.� Deep caught lake trout matured earlier, grew more slowly, relied more heavily on Mysis relicta, and differed in their morphology relative to shallow caught fish.� We found no differences in lipid content or microsatellite allele frequencies between depth groups.� Many aspects of the diet and life history of the deep Flathead fish resemble the humpers of Lake Superior.� Morphologically, the deep Flathead fish show a general correspondence to the patterns exhibited by native deep water forms in Lake Superior and elsewhere.