Dear colleagues, My co-authors and I are happy to share our recent study of Western Hudson Bay beluga habitat use in the Churchill River estuary, Canada, home to the world's largest beluga summer aggregation. We found distinct beluga acoustic patterns that varied with tides, depth and time of day, and overlapped significantly with Port of Churchill operations. This first acoustic assessment provides a critical pre-port expansion reference for evaluating vessel disturbance and support beluga conservation in the proposed National Marine Conservation Area.
Coppolaro VLM, Kirillov S, Isleifson D, Loseto LL and Marcoux M (2026) Establishing an acoustic benchmark of beluga habitat use in the Churchill River estuary, Manitoba. Front. Mamm. Sci. 5:1903254. doi: 10.3389/fmamm.2026.1903254 https://www.frontiersin.org/journals/mammal-science/articles/10.3389/fmamm.2026.1903254/full Abstract Belugas (Delphinapterus leucas) of the Western Hudson Bay (WHB) population migrate to the Churchill River estuary, Manitoba, Canada, forming the world’s largest summer aggregation. This estuary lies within an Ecologically and Biologically Significant Area and is proposed for inclusion in a National Marine Conservation Area (NMCA). However, the drivers of its persistent use by belugas remain poorly understood. Recent reopening and planned expansion of the Port of Churchill may increase vessel traffic and disturbance, underscoring the need to characterize beluga habitat use for impact assessments. This study presents the first passive acoustic monitoring (PAM) survey of beluga habitat use in the Churchill River estuary. Summer recordings were collected outside main port activity to establish a benchmark of beluga vocal behavior and habitat use. Vocal activity was greater during daytime than nighttime, varying with tide and river depth. Upstream activity increased during high tide, while downstream vocalizations were more frequent at low tide. These patterns were consistent with the use of shallow areas for social behavior and suggested movements toward deeper areas associated with socialization and feeding. Persistently high vocal activity in the deeper central estuary highlights its ecological importance and spatial overlap with port operations. Given the strong site fidelity of WHB belugas, this overlap raises concern about increasing beluga exposure to port activity and the potential for anthropogenic disturbance. A marked decline in vocalizations recorded around the time of ship activity may indicate that vessel traffic contributed to changes in beluga vocal activity, although concurrent weather conditions may also have influenced this pattern, hence warranting further investigation. Our findings confirm the Churchill River estuary as WHB beluga key summer habitat; demonstrate PAM as an effective beluga monitoring tool; and provide a critical pre-port expansion acoustic reference to support NMCA designation and beluga conservation. Happy reading, Veronica L.M. Coppolaro, PhD National Research Council of Italy (CNR)
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