Emerging Novelty in the Seal River Estuary off the Coast of Churchill, Manitoba
By Grace MacNaull
Key words: Novelty, Killer Whales (Orcinus Orca), Belugas (Delphinapterus leucas), Hudson Bay, Climate Change
Summary
This paper explores the Hudson Bay marine ecosystem off Churchill, Manitoba, tracing its ecological history, present challenges, and future implications. It discusses the region's diverse dynamics influenced by freshwater flows, ice cover, and species diversity, including migratory mammals and marine life. Highlighting Indigenous traditions of sustainable resource use, it notes climate change's impact on practices and the near-threatened Delphinapterus leucas (beluga) population. Conservation efforts, like proposing a national marine conservation area, are examined alongside economic aspects such as tourism and past developments' environmental impacts. A focal point is the increasing presence of Orcinus Orca (killer whales), their predation on Delphinapterus leucas (belugas), and potential ecosystem shifts due to declining sea ice. The essay emphasizes the need for holistic conservation strategies amidst changing environmental dynamics and emerging ecological novelties off Churchill's coast.
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Ecological genealogy
In the coastal waters off Churchill, Manitoba, a vast portion of the Arctic Ocean known as the Hudson Bay is undergoing a cascading trophic shift leading to emerging novelty within a complex ecosystem. Hudson Bay is confined by Baffin Island and mainland Canada, connected to the Arctic Ocean through the Fury and Hecla Strait as well as the North Atlantic Ocean through the Hudson Strait (Ferguson et al, 2007). The circulation and water mass characteristics within the Hudson Bay are strongly manipulated by the freshwater dynamics, which fluctuate seasonally and geographically in response to ice formation and melt, freshwater runoff, and inputs of marine surface water (Ferguson et al, 2007). The water off the coast of Churchill originates from the Pacific Ocean, which is then cooled, and diluted by the passage through the Arctic Archipelago and enters via Fury, Hecla Strait, and the Hudson Strait.
Historically, the Hudson Bay was essentially ice-covered in winter and ice-free in the summer (Westdal et al., 2017). The ice-free habitat provided seasonally important estuary foraging environments and nursery habitat for many freshwater, anadromous and marine species. These species include Boreogadus saida (Arctic cod), Lipophyrs pholis (shannies) and Cottoidea (sculpins), and year-round habitat for Myoxocephalus quadricornis (fourthorn sculpin). Estuaries such as the one near Churchill, Manitoba bring large concentrations of Delphinapterus leucas (belugas). The use of these estuaries by Delphinapterus leucas (belugas) may be related to moulting and neonate survival, their persistent use of these habitats despite outside pressures, suggests that they must serve an extremely important habitat function (Westdal et al., 2017). The quality, quantity, and duration of seasonal ice cover severely influences the ecology of the nearshore and ice biota, pelagic systems under the ice, and the use of the ice surface as a platform for travel and reproduction (Stewart & Lockhart, 2005). The time of ice formation and breakup determine when habitats and food resources are available, and when the timing is not suitable to a species, the affected must be capable of adapting or moving if they are to survive (Ferguson et al, 2007). Mammals off the coast of Churchill mainly consist of migratory species that are unable to access the surface when ice is present or require ice for offshore access. Pagophilus groenlandicus (harp seal) and Cystophora cristata (hooded seals), along with Delphinapterus leucas (beluga), Balaena mysticetus (bowhead), Monodon monoceros (narwhal), Orcinus Orca (killer), Balaenoptera acutorostrata (minke) and Megaptera novaeangliae (humpback) whales are all typical seasonal visitors to this region. Ursus maritimus (Polar bears), Odobenus rosmarus (Atlantic walrus), Pusa hispida (ringed seal), Erignathus barbatus (bearded seal) and Phoca vitulina (harbour seals) inhabit the waters off the coast of Churchill year-round. Chronological reporting illustrates a progression in Orcinus Orca (killer whale) use of the Hudson Bay region, increasing from no evidence in the early 1900s to a sporadic occurrence in the 1980’s, to occasional and possibly annual in the 1990’s, to an exponential increase in the 2010’s, so that Orcinus Orca (killer whales) occur off the coast of Churchill on an annual basis today (Ferguson et al, 2010). The presence and timing of all these species depend upon climate controls, seawater, freshwater runoff, seasonal circulation, sea ice, water column stability, biological productivity, surface circulation, and coastal emergence. |
Marine mammal prey items of killer whales reported in the Hudson Bay region. Higdon et al 2011
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Present tense
In the coastal waters off Churchill, Manitoba, a vast portion of the Arctic Ocean known as the Hudson Bay is undergoing a cascading trophic shift leading to emerging novelty within a complex ecosystem. Hudson Bay is confined by Baffin Island and mainland Canada, connected to the Arctic Ocean through the Fury and Hecla Strait as well as the North Atlantic Ocean through the Hudson Strait (Ferguson et al, 2007). The circulation and water mass characteristics within the Hudson Bay are strongly manipulated by the freshwater dynamics, which fluctuate seasonally and geographically in response to ice formation and melt, freshwater runoff, and inputs of marine surface water (Ferguson et al, 2007). The water off the coast of Churchill originates from the Pacific Ocean, which is then cooled, and diluted by the passage through the Arctic Archipelago and enters via Fury, Hecla Strait, and the Hudson Strait.
Historically, the Hudson Bay was essentially ice-covered in winter and ice-free in the summer (Westdal et al., 2017). The ice-free habitat provided seasonally important estuary foraging environments and nursery habitat for many freshwater, anadromous and marine species. These species include Boreogadus saida (Arctic cod), Lipophyrs pholis (shannies) and Cottoidea (sculpins), and year-round habitat for Myoxocephalus quadricornis (fourthorn sculpin). Estuaries such as the one near Churchill, Manitoba bring large concentrations of Delphinapterus leucas (belugas). The use of these estuaries by Delphinapterus leucas (belugas) may be related to moulting and neonate survival, their persistent use of these habitats despite outside pressures, suggests that they must serve an extremely important habitat function (Westdal et al., 2017). The quality, quantity, and duration of seasonal ice cover severely influences the ecology of the nearshore and ice biota, pelagic systems under the ice, and the use of the ice surface as a platform for travel and reproduction (Stewart & Lockhart, 2005). The time of ice formation and breakup determine when habitats and food resources are available, and when the timing is not suitable to a species, the affected must be capable of adapting or moving if they are to survive (Ferguson et al, 2007). Mammals off the coast of Churchill mainly consist of migratory species that are unable to access the surface when ice is present or require ice for offshore access. Pagophilus groenlandicus (harp seal) and Cystophora cristata (hooded seals), along with Delphinapterus leucas (beluga), Balaena mysticetus (bowhead), Monodon monoceros (narwhal), Orcinus Orca (killer), Balaenoptera acutorostrata (minke) and Megaptera novaeangliae (humpback) whales are all typical seasonal visitors to this region. Ursus maritimus (Polar bears), Odobenus rosmarus (Atlantic walrus), Pusa hispida (ringed seal), Erignathus barbatus (bearded seal) and Phoca vitulina (harbour seals) inhabit the waters off the coast of Churchill year-round. Chronological reporting illustrates a progression in Orcinus Orca (killer whale) use of the Hudson Bay region, increasing from no evidence in the early 1900s to a sporadic occurrence in the 1980’s, to occasional and possibly annual in the 1990’s, to an exponential increase in the 2010’s, so that Orcinus Orca (killer whales) occur off the coast of Churchill on an annual basis today (Ferguson et al, 2010). The presence and timing of all these species depend upon climate controls, seawater, freshwater runoff, seasonal circulation, sea ice, water column stability, biological productivity, surface circulation, and coastal emergence. |
Location of deployment of AURAL-M2 autonomous recording devices used to record whale acoustic calls. Ferguson et al, 2010.
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future tradjectory
The spatial and temporal occurrence of Orcinus Orca (killer whales) is related to predictable and abundant prey sources, such as Delphinapterus leucas (belugas). Orcinus Orca (killer whale) predation has been cited as a potential factor in the decline of several marine mammal populations over decades (Guinet et al, 1992). Rapid climate change and the possibility of longer ice-free periods within the Seal River estuary leaves Orcinus Orca (killer whales) the potential to regulate population growth of Delphinapterus leucas (beluga) populations. Delphinapterus leucas (belugas) play a crucial role in maintaining the balance of the Arctic ecosystem. As a higher mammal on the trophic scale, they help regulate fish populations (Schueman, 2023). The feeding habits of Delphinapterus leucas (belugas) also aid in nutrient distribution, benefitting the entire food web, while their migration patterns help transport nutrients between different regions, contributing to the overall health and productivity of Arctic oceans. Changes in populations between these two species and the possibility of year-round presence of the Orcinus Orca (killer whale) due to decreasing annual sea ice coverage from rising temperatures paves the way for an emerging novelty within the ecosystem off the coast of Churchill, Manitoba. The more recent introduction of Orcinus Orca (killer whales) into the Hudson Bay is just one example of how species may be able to adapt or manipulate new climate conditions when given the opportunity and how these behaviours can have lasting consequences and create novel situations. Sightings of Orcinus Orca (killer whales) have been reported across the entirety of Hudson Bay, ranging from the Foxe Basin, the northwest, and to the southwest. Results of predation suggest that conservation of marine mammals in Hudson Bay should consider Orcinus Orca (killer whales) effects since they have the protentional to regulation population growth of prey populations and create emerging novelty within anthropogenically altered ecosystems.
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Prey selection by a group of killer whales in Hudson Bay used to model the possible effects of predation on marine mammal populations. Ferguson et al, 2010.
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References
Breed, G. A., Matthews, C. J., Marcoux, M., Higdon, J. W., LeBlanc, B., Petersen, S. D., Orr, J., Reinhart, N. R., & Ferguson, S. H. (2017). Sustained disruption of narwhal habitat use and behavior in the presence of Arctic Killer Whales. Proceedings of the National Academy of Sciences, 114(10), 2628–2633. https://doi.org/10.1073/pnas.1611707114
Ferguson, S. H., Higdon, J. W., & Westdal, K. H. (2012). Prey items and predation behavior of killer whales (Orcinus orca) in Nunavut, Canada based on Inuit Hunter interviews. Aquatic Biosystems, 8(1), 3. https://doi.org/10.1186/2046-9063-8-3
Government of Canada, S. C. (2023, February 1). Census profile, 2021 census of Populationprofile Table. Profile table, Census Profile, 2021 Census of Population - Churchill, Town (T) [Census subdivision], Manitoba. https://www12.statcan.gc.ca/census-recensement/2021
Guinet C., P. Jouventin, and H. Weimerskirch. 1992. Population changes, movements of southern elephant seals in Crozet and Kerguelen Archipelagos in the last decades. Polar Biol. 12: 349–356.
Higdon, J. W., Hauser, D. D., & Ferguson, S. H. (2011a). Killer whales (orcinus orca) in the Canadian Arctic: Distribution, prey items, group sizes, and seasonality. Marine Mammal Science, 28(2). https://doi.org/10.1111/j.1748-7692.2011.00489.x
Higdon, J. W., & Ferguson, S. H. (2009). Loss of Arctic Sea Ice Causing Punctuated Change in Sightings of Killer Whales (Orcinus Orca) over the Past Century. Ecological Applications, 19(5), 1365–1375. https://doi.org/10.1890/07-1941.1
Loseto, L. L., Hoover, C., Ostertag, S., Whalen, D., Pearce, T., Paulic, J., Iacozza, J., & MacPhee, S. (2018). Beluga whales (delphinapterus leucas), environmental change and marine protected areas in the Western Canadian Arctic. Estuarine, Coastal and Shelf Science, 212, 128–137. https://doi.org/10.1016/j.ecss.2018.05.026
Newton, S. T. (2000, March 1). Sustainable development for Canada’s Arctic and sub-arctic communities, a case study of Churchill, Manitoba. MSpace Angular. https://mspace.lib.umanitoba.ca/items/d1938a63-1619-4679-a8c5-bf3bb15aa25c
R Reeves, & Mitchell, E. D. (2011, September 29). Beluga whale. The Canadian Encyclopedia. https://www.thecanadianencyclopedia.ca/en/article/beluga
Richard, P.R. 2005. An estimation of the Western Hudson Bay beluga population size in 2004. DFO Can. Sci. Advis. Sec. Res. Doc. 2005/017.
Rutgers, J.-S. (2024, March 8). Manitoba’s Arctic Coast is home to seals, polar bears and 60,000 belugas. here’s Canada’s chance to protect it. The Narwhal. https://thenarwhal.ca/hudson-bay-beluga-protection/
Schueman, L. J. (2023, June 6). How beluga whales balance life in the Arctic Seas. One Earth. https://www.oneearth.org/species-of-the-week-beluga-whales/#:~:text=Beluga%20whales%20play%20a%20vital,benefiting%20the%20entire%20food%20web.
Westdal, K. H., Davies, J., McPherson, A., Orr, J., & Ferguson, S. H. (2017). Behavioural changes in belugas (delphinapterus leucas) during a killer whale (orcinus orca) attack in southwest Hudson Bay. The Canadian Field-Naturalist, 130(4), 315. https://doi.org/10.22621/cfn.v130i4.1925
Ferguson, S. H., Higdon, J. W., & Westdal, K. H. (2012). Prey items and predation behavior of killer whales (Orcinus orca) in Nunavut, Canada based on Inuit Hunter interviews. Aquatic Biosystems, 8(1), 3. https://doi.org/10.1186/2046-9063-8-3
Government of Canada, S. C. (2023, February 1). Census profile, 2021 census of Populationprofile Table. Profile table, Census Profile, 2021 Census of Population - Churchill, Town (T) [Census subdivision], Manitoba. https://www12.statcan.gc.ca/census-recensement/2021
Guinet C., P. Jouventin, and H. Weimerskirch. 1992. Population changes, movements of southern elephant seals in Crozet and Kerguelen Archipelagos in the last decades. Polar Biol. 12: 349–356.
Higdon, J. W., Hauser, D. D., & Ferguson, S. H. (2011a). Killer whales (orcinus orca) in the Canadian Arctic: Distribution, prey items, group sizes, and seasonality. Marine Mammal Science, 28(2). https://doi.org/10.1111/j.1748-7692.2011.00489.x
Higdon, J. W., & Ferguson, S. H. (2009). Loss of Arctic Sea Ice Causing Punctuated Change in Sightings of Killer Whales (Orcinus Orca) over the Past Century. Ecological Applications, 19(5), 1365–1375. https://doi.org/10.1890/07-1941.1
Loseto, L. L., Hoover, C., Ostertag, S., Whalen, D., Pearce, T., Paulic, J., Iacozza, J., & MacPhee, S. (2018). Beluga whales (delphinapterus leucas), environmental change and marine protected areas in the Western Canadian Arctic. Estuarine, Coastal and Shelf Science, 212, 128–137. https://doi.org/10.1016/j.ecss.2018.05.026
Newton, S. T. (2000, March 1). Sustainable development for Canada’s Arctic and sub-arctic communities, a case study of Churchill, Manitoba. MSpace Angular. https://mspace.lib.umanitoba.ca/items/d1938a63-1619-4679-a8c5-bf3bb15aa25c
R Reeves, & Mitchell, E. D. (2011, September 29). Beluga whale. The Canadian Encyclopedia. https://www.thecanadianencyclopedia.ca/en/article/beluga
Richard, P.R. 2005. An estimation of the Western Hudson Bay beluga population size in 2004. DFO Can. Sci. Advis. Sec. Res. Doc. 2005/017.
Rutgers, J.-S. (2024, March 8). Manitoba’s Arctic Coast is home to seals, polar bears and 60,000 belugas. here’s Canada’s chance to protect it. The Narwhal. https://thenarwhal.ca/hudson-bay-beluga-protection/
Schueman, L. J. (2023, June 6). How beluga whales balance life in the Arctic Seas. One Earth. https://www.oneearth.org/species-of-the-week-beluga-whales/#:~:text=Beluga%20whales%20play%20a%20vital,benefiting%20the%20entire%20food%20web.
Westdal, K. H., Davies, J., McPherson, A., Orr, J., & Ferguson, S. H. (2017). Behavioural changes in belugas (delphinapterus leucas) during a killer whale (orcinus orca) attack in southwest Hudson Bay. The Canadian Field-Naturalist, 130(4), 315. https://doi.org/10.22621/cfn.v130i4.1925