Alison Gladwell
- BSc (Dalhousie University, 2019)
Topic
Social influence on vessel behaviour around cetaceans in the waters of Northeast Vancouver Island
Department of Geography
Date & location
- Tuesday, September 3, 2024
- 11:00 A.M.
- David Turpin Building, Room B215
Examining Committee
Supervisory Committee
- Dr. Chris Darimont, Department of Geography, University of Victoria (Supervisor)
- Dr. Valeria Vergara, Department of Geography, UVic (Member)
- Dr. Christie McMillan, Department of Geography, UVic (Member)
External Examiner
- Dr. Rob Williams, Chief Scientist, Oceans Initiative
Chair of Oral Examination
- Dr. Bruce Ravelli, Department of Sociology, UVic
Abstract
When managing human behaviour around wildlife, regulations are often designed to mitigate disturbance to vulnerable species. Yet, patterns and drivers of compliance with such regulations are poorly understood. In partnership with the Marine Education and Research Society, we assessed local compliance rates and examined patterns underlying vessel-whale encounters by observing vessel behaviours around marine mammals. In the summers of 2022 and 2023 (n = 475 observation hours, 902 interactions between marine mammals and boats), we assessed motorized vessel compliance to Canada’s Marine Mammal Regulations and examined a suite of boater behaviours relating to humpback (Megaptera novaeangliae) and killer whales (Orcinus orca) in Northeast Vancouver Island. Recreational and ecotour vessels had similar rates of compliance (85 and 87%, respectively), with the lowest compliance rates around killer whales (74%). Complementary modelling showed that closer distances between vessels and whales were associated with vessels that spent more time with an animal or that were idle. In contrast, greater distances from the whales were associated with interactions involving a higher number of vessels. Assessing other measures of potential disturbance, we found that the number of vessels surrounding an animal varied by study site and was higher in encounters after VHF radio communication about the focal whale compared to encounters without mention. Finally, the time a vessel spent with a whale was higher for vessels at idle and slow/medium speeds compared to vessels travelling at faster speeds. Results from this work can inform geographic and practical areas of focus for education, enforcement and policy development.