Date of Award


Publication Type

Master Thesis

Degree Name



Great Lakes Institute for Environmental Research


Aaron T. Fisk


Graham D. Raby




There exists potential to better understand ecology through physiological measurements in fish. By bridging the gap between ecology and physiology we can better understand fish and the challenges they face in a changing climate. However, to do so we also need to be able to more successfully make physiological measurements in free-swimming fish. To examine the relationship between physiology and ecology in fish, I looked at two species, bowfin (Amia calva) and largemouth bass (Micropterus salmoides), two phylogenetically distant fish that share preferred habitat and prey but are physiologically very different. Fish were given heart rate loggers and after a 24-hour period of recovery were exposed to a stressor to collect an elevated heart rate before being sealed in respirometry chambers to collect oxygen consumption rate data simultaneously for the remainder of the trial. Proceeding each trial, muscle and liver tissue samples were collected from each fish. Calibrations of heart and oxygen consumption rate data revealed a weak relationship between the two in largemouth bass which exhibited a greater range in heart rate than bowfin did. Tissue samples collected were run for δ13C and δ15N and all variables were controlled for mass before comparing isotopic values to metabolic rate. No relationships were found between isotopic data and metabolic rate in either species. However, all experiments here took place under a narrow range of conditions and therefore there is promise for future work should these relationships be further explored under a greater range of conditions. If we can establish stronger relationships between these techniques, we can increase the toolbox available for quantifying the role of fish in nature and our understanding of their ecology and physiology through direct field measurements.