Changes in sea ice and range expansion of sperm whales in the eclipse sound region of Baffin Bay, Canada

Abstract

Sperm whales (Physeter macrocephalus) are a cosmopolitan species but are only found in ice‐free regions of the ocean. It is unknown how their distribution might change in regions undergoing rapid loss of sea ice and ocean warming like Baffin Bay in the eastern Canadian Arctic. In 2014 and 2018, sperm whales were sighted near Eclipse Sound, Baffin Bay: the first recorded uses of this region by sperm whales. In this study, we investigate the spatiotemporal distribution of sperm whales near Eclipse Sound using visual and acoustic data. We combine several published open‐source, data sets to create a map of historical sperm whale presence in the region. We use passive acoustic data from two recording sites between 2015 and 2019 to investigate more recent presence in the region. We also analyze regional trends in sea ice concentration (SIC) dating back to 1901 and relate acoustic presence of sperm whales to the mean SIC near the recording sites. We found no records of sperm whale sightings near Eclipse Sound outside of the 2014/2018 observations. Our acoustic data told a different story, with sperm whales recorded yearly from 2015 to 2019 with presence in the late summer and fall months. Sperm whale acoustic presence increased over the 5‐year study duration and was closely related to the minimum SIC each year. Sperm whales, like other cetaceans, are ecosystem sentinels, or indicators of ecosystem change. Increasing number of days with sperm whale presence in the Eclipse Sound region could indicate range expansion of sperm whales as a result of changes in sea ice. Monitoring climate change‐induced range expansion in this region is important to understand how increasing presence of a top‐predator might impact the Arctic food web.

Contrasting ecological information content in whaling archives with modern cetacean surveys for conservation planning and identification of historical distribution changes

“…We further expect this species to be less sensitive to climatic change than other whales with more restrictive habitat preferences. To our knowledge, evidence of sperm whale range shifts related to climatic change is limited to examples where a pod expanded into new habitats made accessible by sea ice melting (Posdaljian et al., 2022).…”

“…To our knowledge, such avoidance behavior has never been documented in marine mammals at the scales we considered (i.e., >200 nm). As a highly migratory species adaptable to new habitats (Posdaljian et al., 2022), this is an intriguing possibility for sperm whales, with implications for recolonization potential.…”

Climate change and extreme events are changing the biology of Polar Regions

“…Loss of sea ice negatively affects organisms that rely on ice (e.g. emperor penguins and polar bears; Boonstra et al, 2020; Chown et al, 2022; Jenouvrier et al, 2020, 2021; Stirling & Derocher, 2012; Wege et al, 2021) but can lead to range expansion for other species (Chan et al, 2019; Chown et al, 2022; Christiansen et al, 2014; Feng et al, 2018; Posdaljian et al, 2022). Novel feeding interactions can then develop, which amplify the impact of species redistribution (Pecuchet et al, 2020).…”

High Arctic “hotspots” for sperm whales (Physeter macrocephalus) off western and northern Svalbard, Norway, revealed by multi-year Passive Acoustic Monitoring (PAM)

“…Even though sperm whales are known to be seasonally resident in the Arctic, their geographic distribution at a finer scale and the timing of their arrivals and departures from the north are not well documented 5 . Sea ice is known to limit their distribution; sperm whales typically avoid sea ice covered areas 6 , 7 . In the North Pacific, sperm whales are found in Alaskan waters 8 , 9 , in the Bering Sea, the Bering Strait and the southern Chukchi Sea, up to latitudes of about 68° N 7 , 10 .…”

“…In contrast, in the North Atlantic, the sperm whales’ range extends much further north. Studies have reported sperm whales at latitudes of 75° N in Baffin Bay in the Northwest Atlantic 6 , 11 , 12 . In the Northeast Atlantic, the sperm whale’s range extends north to the Svalbard Archipelago, with observations as far as 81° N 13 – 17 .…”