Canada's polynyas
Canada’s Arctic is dotted with 23 polynyas that are critical habitats for marine mammals and birds. These geographically fixed regions of (mostly) open water surrounded by sea ice form in two ways. Latent-heat (or coastal) polynyas form when wind and currents push ice away from a coastline or a mass of fixed ice, while sensible-heat (or open-ocean) polynyas form when relatively warm water upwells from the ocean’s lower depths to the surface, slowing or preventing the formation of ice.
This interactive map depicts Canada’s 23 polynyas. Hover your mouse over the map and click a highlighted polynya to learn more.
Type
Sensible heat and latent heat
Formation (mean dates)
Open: As early as December, but usually open by April
Close: Mid-October to mid-November
Biodiversity
• Feeding ground for white and bowhead whales in spring and early summer
• Critical to migratory sea ducks that stage and feed in early spring
• High densities of seals and polar bears throughout winter
Type
Latent heat
Formation (mean dates)
Open: February to June
Close: mid-October to early November
Biodiversity
• Ringed seal and bearded seal habitat
• 60 to 70 per cent of Canada's common eider population can be observed here
Type
Unknown
Formation (mean dates)
Open: Mid to late November
Close: Starts in June
Biodiversity
• Nearby Southampton Island is a migratory bird sanctuary and provides summer and winter habitat for Atlantic walrus
• Important spring and summer migration routes for bowhead whales and narwhals
• Landfast ice in region frequented by polar bears
Type
Unknown
Formation (mean dates)
Open: Highly variable but at least by April
Close: From early September to early October, but never ice free
Biodiversity
• Important nursery area for Eastern Arctic bowhead from late July to October
• Large numbers of narwhal and beluga whales in summer
Type
Latent heat
Formation (mean dates)
Open: As early as January in some areas, mid-February or March for others
Close: Mid-October starting in northwestern corner
Biodiversity
• Seasonal migration of narwhal in region
• Important habitat for bowhead whales
• Ringed seals, bearded seals and polar bears are also abundant in winter
Type
Unknown
Formation (mean dates)
Open: Unknown
Close: Unknown
Biodiversity
• Year-round habitat for bearded seals, polar bears and ringed seals
• Important wintering ground for belugas and walrus
• Important feeding, staging and breeding area for more than 15 species of seabirds
• Frequented by killer whales
Type
Unknown
Formation (mean dates)
Open: Late March to early April
Close: Mid-July
Biodiversity
• Shores around polynya are a major spring stopover sites for migrating seabirds and site of largest Iceland gull colony in Canada
• Late summer feeding area for black-legged kittiwake and black guillemot
• Summer beluga habitat
• Key habitat for Greenland halibut
Type
Latent heat
Formation (mean dates)
Open: April to May
Close: Unknown
Biodiversity
• Habitat for killer whales, walruses, ringed seals, bearded seals, harp seals, narwhal and polar bears are abundant in winter
• Summer beluga habitat
• Habitat for bowhead whale and species of marine birds
Type
Unknown
Formation (mean dates)
Open: Unknown
Close: Unknown
Biodiversity
Unknown
Type
Latent heat
Formation (mean dates)
Open: Late December to March
Close: Late September to December
Biodiversity
• Part of an important summer feeding ground for belugas and narwhals
Type
Latent heat
Formation (mean dates)
Open: Cracks start in January
Close: Usually by mid-October
Biodiversity
• Important area for Eastern Arctic/Baffin Bay beluga population, which uses the area’s shallow estuaries in the summer as safe feeding grounds from killer whales
• Narwhals feed in deeper bays and fiords in summer
• Arctic char migrate from lakes to feed
• Important area for black-legged kittiwake, northern fulmar, king eider and common eider
Type
Latent heat
Formation (mean dates)
Open: Mid-November to mid-December
Close: Starts in late September and is ice-covered by late October
Biodiversity
• Incredibly biodiverse region
• Migratory route for bowhead whales, belugas, narwhal, killer whales and seals
• Also supports variety of marine fish, such as Arctic cod, and Atlantic walrus, polar bears and sea birds, such as northern fulmar and black-legged kittiwake
Type
Unknown
Formation (mean dates)
Open: Unknown
Close: Unknown
Biodiversity
• Part of migration route for belugas
• Feeding ground for ringed seals
• Part of polar bear and bowhead whale habitat
Type
Latent heat
Formation (mean dates)
Open: Late June to early July
Close: Late August to early September
Biodiversity
• Important year-round area for walrus
• Nearby Cheyne Islands support the largest nesting population of the Ross’ gull
Type
Sensible heat
Formation (mean dates)
Open year-round
Biodiversity
• Important year-round area for walrus
• Nearby Cheyne Islands support the largest nesting population of the Ross’ gull
Type
Latent heat
Formation (mean dates)
Open: December to July there are open areas, but is never completely ice-free
Close: Starts in September, and is almost entirely ice-covered by October/November
Biodiversity
• Supports year round population of 300-500 Atlantic walrus
• Used in the summer by belugas, killer whales and seals
• Near site of several large seabird colonies including the black guillemot, northern fulmar, common eider and the glaucous gull
Type
Latent heat
Formation (mean dates)
Open: January
Close: Mid to late October
Biodiversity
• Summer habitat for Atlantic walrus, High Arctic beluga and ringed seals
• Part of an important maternity habitat for polar bears
• Supports breeding grounds for more than 500,000 marine birds
Type
Latent heat
Formation (mean dates)
Open: February, though it fuses with North Water polynya as early as June
Close: Late October
Biodiversity
• Important migration route and summer feeding area for approximately 20,000 Baffin Bay narwhal
• Cape Hay supports colonies of thick-billed murre and black-legged kittiwake and is a staging area for northern fulmar
Type
Latent heat
Wildlife
• Summer habitat for Atlantic walrus, High Arctic beluga and ringed seals
• Part of an important maternity habitat for polar bears
• Supports breeding grounds for more than 500,000 marine birds
Biodiversity
• Supports breeding grounds for more than 500,000 marine birds, including about 30,000 pairs, or 16 per cent of the population, of black-legged kittiwake
• Summer habitat for Atlantic walrus, High Arctic beluga and ringed seals
• Part of an important maternity habitat for polar bears
Type
Sensible and latent heat polynya
Formation (mean dates)
Open: January
Close: Mid to late October
Biodiversity
• Winter habitat for belugas, bowhead whales, seals and polar bears
• Supports a plankton bloom beginning in early April that helps sustain Arctic cod, a keystone species in the polynya’s ecosystem
Type
Unknown
Formation (mean dates)
Open: Unknown
Close: Unknown
Biodiversity
• Habitat for walrus and seals
• Nesting ground for many bird species including the common eider, red-throated loon, snow goose, Arctic tern and many others
Type
Unknown
Formation (mean dates)
Open: November
Close: April
Biodiversity
Unknown
Type
Unknown
Formation (mean dates)
Open: Unknown
Close: Unknown
Biodiversity
• Along with islands, polynya is critical to survival of common eider in region
• Area of high biodiversity and providing habitat for walrus, ringed seals, polar bears, belugas, sea urchins, sea cucumbers and bivalves
Map: Meltofte, H. (ed.) 2013. Arctic Biodiversity Assessment.
Status and trends in Arctic biodiversity. Conservation of Arctic Flora and Fauna, Akureyri.
Text: Michela Rosano
