Distribution of beluga in western Hudson Bay with respect to estuary habitat characteristics and vessel traffic
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Date
2022-03-30
Authors
Ausen, Emma
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Abstract
Western Hudson Bay is undergoing habitat changes associated with increased anthropogenic activities including vessel traffic from shipping and whale watching ecotourism. These river estuaries are habitat for the Western Hudson Bay (WHB) beluga whale, the largest know beluga population. This thesis addresses two important questions, which environmental conditions contribute to critical beluga habitat in the western Hudson Bay, and what is the response of beluga to tourism vessel traffic in the Churchill River estuary. Beluga were identified in nadir imagery from a 2018 summer aerial survey of the Nelson, Churchill and Seal River estuaries, and oblique images taken of the Churchill River estuary in August 2020. The location of beluga within each survey area was modeled with respect to remotely sensed environmental data. Beluga habitat use was found to be associated with rivers as well as the concentration of total suspended sediments, and colored dissolved organic matter. Using environmental characteristics, a previously unidentified important habitat unit for beluga was discovered in the Knife River estuary. Distance measurements between belugas and tourist vessels were obtained from oblique images using trigonometric equations and georeferencing points taken in the Churchill River estuary. Through distance analysis, it was found that beluga showed attraction to kayaks, avoidance to paddleboards, and independence from motorboats and Zodiacs. Results from this thesis should inform management decisions for the WHB beluga population, including the establishment of a National Marine Protected Area which is currently under consideration.
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beluga, photogrammetry, gis, whale-watching, remote sensing