Date of Award
Nigel E. Hussey
Biologging, Metabolism, Respirometry, Sharks
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Metabolic rate is intricately linked to the ecology of organisms and can provide a framework to study the behaviour, life history, population dynamics, and trophic impact of a species. Acquiring measures of metabolic rate, however, has proven difficult for large water-breathing animals such as sharks, greatly limiting our understanding of the energetic lives of these highly threatened and ecologically important fish. The following thesis presents the first estimates of metabolic rate for one severly understudied and near-threatened species, the long-lived Greenland shark (Somniosus microcephalus). Resting and active routine metabolic rates were estimated through field respirometry conducted on four relatively large-bodied individuals (33-126 kg), including the largest individual shark studied via respirometry. Despite recording very low whole-animal resting metabolic rates, estimates were well explained by derived interspecies allometric and temperature scaling relationships. Combining these results with data acquired from biologger deployments on free-roaming sharks allowed for the estimation of field metabolic rates for individuals inhabiting the Eastern Canadian Arctic. The estimated low energy needs of Greenland sharks in the wild translated to equally low estimates of prey consumpion rate at the individual level. However, when assessed at the scale of localized populations in two coastal fjord ecosystems and across all of Baffin Bay, prey consumption by Greenland sharks is assumed to play a key role in the top-down regulation of Arctic marine food webs, though important data deficiencies must be addressed before final conclusions can be drawn.
Ste-Marie, Eric, "Life in the slow lane: Estimating the metabolic rate and trophic impact of the Greenland shark (Somniosus microcephalus)" (2021). Electronic Theses and Dissertations. 8538.