Date of Award

2026

Document Type

Open Access Master's Thesis

Degree Name

Master of Science in Biological Sciences (MS)

Administrative Home Department

Department of Biological Sciences

Advisor 1

Gordon Paterson

Committee Member 1

Stacy Cotey

Committee Member 2

Christopher Adams

Abstract

Bioenergetic bottlenecks represent the condition during which organisms function in a net energy deficit. Subsequently, for pollutants such as Hg with extended half-lives in biological tissues, this energetic imbalance can result in bioamplification; the condition when organisms lose body weight and chemical portioning capacity at a faster rate than they can eliminate those chemicals. Here, we measured total Hg concentrations in emaciated Lake Charr (Salvelinus namaycush) collected from Lake Superior’s maximum depth (400+ m) and compared against concentrations in healthy individuals. Total Hg in emaciated fish averaged 0.76 ± 0.2 µg/g (wet wt.) with all fish exceeding FDA and EPA advisory levels. Interestingly, these fish were of the high lipid siscowet ecotype for which whole body lipid contents can exceed 60% (dry wt.). For emaciated fish, their high Hg concentrations suggest persistence in a zombie-like state for extended periods given mercury’s tendency to bioaccumulate in protein. The waters in which these fish reside have temperatures that are likely to remain consistent year-round at ~4 ºC; at such consistently low temperatures and with their higher energy densities, siscowet lake trout in Lake Superior may be able to endure substantial periods of food limitation and starvation prior to mortality occurring. The frequency of emaciated individuals occurring within the Lake Superior siscowet population is currently unknown. Which also has implications for human health as ‘skinny’ fish can increase the risks of the adverse health effects associated with dietary Hg exposure due to more concentrated levels.

Download

Available for download on Tuesday, April 13, 2027

Share

COinS