Bowhead whale year-round acoustic presence and habitat associations in the Amundsen Gulf, Western Canadian Arctic, 2018–2019

Abstract

Understanding the temporal and spatial distribution of bowhead whales is ecologically and culturally important in the context of a rapidly changing climate. Long-term monitoring can reveal alterations in the bowhead whale distribution range, spatiotemporal patterns, and migration phenology that can be responses to global change. However, Arctic ecosystems are challenging to monitor. Here, we deployed passive acoustic recorders at three locations in the southern Amundsen Gulf (western Canadian Arctic) between September 2018 and September 2019 to detect bowhead whale presence, quantify their seasonal occurrence, and examine the oceanographic conditions that correlate with bowhead occurrence. Results show clear seasonal patterns in the occurrence of bowheads with increased acoustic presence in spring/summer at all sites. In contrast to their typical migratory behavior, bowhead sounds were detected throughout the year at all sites, providing evidence of a number of overwintering animals in what is normally their summer feeding ground. The continuous occupancy of bowheads from May to August at all sites emphasizes the importance of this area as a core foraging ground for this population. Our results indicate a clear selection for the shallowest habitat over an annual cycle. Statistical habitat modeling indicated associations between bowhead occurrence and decreasing sea-ice coverage, wind speed, temperature, and salinity. Positive relationships between bowhead detections and zooplankton density suggest a predator-prey dynamic. These results are the first that cover an entire annual cycle of bowhead presence in the southern Amundsen Gulf, providing new knowledge and current status of bowhead habitat use to support effective management under ongoing Arctic change.