Date of Award


Publication Type

Master Thesis

Degree Name



Great Lakes Institute for Environmental Research

First Advisor

Dr. Joel Gagnon

Second Advisor

Dr. Christopher Weisener


Health and environmental sciences




We used a focused ion beam (FIB) to create thin sections from the post-hatch and core regions of Chinook salmon (Oncorhynchus tshawytscha) otoliths. The nano-scale chemistry and structure of these regions was characterized in thin section using scanning electron microscopy (SEM) in conjunction with cathodoluminescence (CL) and high resolution transmission electron microscopy (HRTEM). The results constrained the relative distribution of several elements; silicon-enriched nodules were found in the post-hatch otolith, and manganese, an element known to be enriched in the greater otolith core, was most concentrated at the center of primordia and at the primordia-core interfaces. Calcium was less abundant and carbon was observed in greater relative concentrations in the primordia relative to the surrounding core. HRTEM revealed a lack of crystallinity in the core relative to the post-hatch otolith. This is the first study to successfully thin-section an otolith using a FIB and characterize the thin section using HRTEM.