Marine mammals in a changing Arctic - assessing environmental and anthropogenic drivers of habitat use and behavioral changes using non-invasive, automated technologies

Abstract

Rapid and unprecedented changes are reshaping Arctic marine ecosystems, driving shifts in sea ice, species distribution, and human activity that have profound consequences for marine mammals. Many regions of the Canadian Arctic and sub-Arctic lack the long-term biological reference data needed to assess marine mammal vulnerability to climate- and human-driven pressures. This thesis addresses these gaps by applying remote, non-invasive automated monitoring techniques to document marine mammal presence, habitat use, and acoustic responses to anthropogenic disturbance across two understudied ecologically important study areas under consideration for protection. To fill these gaps, I carried out extensive fieldwork, integrated complementary monitoring techniques, performed in-depth bioacoustics and time-lapse image analyses, and applied statistical modelling to advance a comprehensive understanding of marine mammal habitat use and acoustic behavior in a rapidly changing environment. Across four research chapters, I examined species diel and seasonal vocal patterns, habitat use, and acoustic behavior in relation to environmental drivers; provided the first evidence of walrus acoustic responses to vessel traffic; established acoustic baseline data for beluga use of an estuary prior to the port reopening and anticipated major industrial upgrades; and investigated an unprecedented bowhead whale sighting outside the species’ typical range. Results from research in Southampton Island, Nunavut, established the first multi-species acoustic baseline for the proposed Marine Protected Area, revealing seasonal and diurnal patterns in belugas, walruses, bearded seals, and bowhead whales, and identifying key ecological functions from their vocal behavior. Examples of vocalizations were contributed to online repositories, helping fill critical gaps in Arctic marine mammal bioacoustics. Building on this work, I demonstrated that walrus vocal activity decreased during vessel transits, highlighting potential disturbance and the need for local updated maritime navigation mitigation measures. In the Churchill River estuary, I identified relationships between beluga vocal behavior and habitat features, establishing an essential baseline prior to the reopening of the port. Finally, time-lapse imagery provided the first group sighting of bowhead whales in coastal Manitoba, suggesting potential climate-driven range shifts and population recovery. Collectively, this thesis advances our understanding of marine mammal ecology and acoustic behavior. It demonstrates the value of automated tools for detecting environmental influences on species presence and vocal behavior, quantifying species responses to disturbance, and filling critical knowledge gaps in data-poor regions. The findings provide critical insight for evaluating species-specific reactions to underwater noise in the study areas, inform future MPA planning and vessel traffic mitigation measures, and underscore the urgency of long-term, integrated monitoring to support effective conservation and management in a rapidly changing Arctic.