Date Approved

2026

Degree Type

Open Access Senior Honors Thesis

Department or School

Biology

First Advisor

Julie Reinhardt, Ph.D.

Second Advisor

Kristi Judd Ph.D.

Third Advisor

Natalie Dove, Ph.D.

Abstract

The Great Lakes top predator Salvelinus namaycush (lake trout) suffers from Thiamine Deficiency Complex (TDC), which causes neurological problems and inhibits survival in young lake trout. The lake trout population in northern Lake Michigan experiences insufficient natural recruitment, necessitating yearly stocking. Few treatments have been explored, but preliminary studies in a hatchery setting suggest that increasing tissue thiamine promotes survival; thus, we expected a novel thiamine treatment to boost the foraging rate and weight of lake trout fry. We raised the eggs of six wild lake trout pairs, and applied treatments at both the egg stage and the hatch stage. When fish reached six months of age, we evaluated foraging rate on 40 fish in the treatment and control groups of two crosses. Growth was measured as the average weight of fish following foraging trials. Although treatment affected both foraging (p=0.002) and growth (p=7.7e-7), there was a significant interaction between cross and treatment for both foraging (p=0.0007) and growth trials (p=0.0004). While our results were statistically inconclusive, future experiments on the effects of treatment should include more replicates across a variety of parental crosses. If a thiamine treatment proves effective in the future, it might be applied to hatchery-raised stock fish: treatment may reverse the deleterious effects of TDC on natural recruitment, promoting the long-term health and stability of the Lake Michigan population.

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