How Marine Life Survives the Extreme Cold  - Oceana Canada
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December 23, 2025

How Marine Life Survives the Extreme Cold 

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Polar bear mother with two cubs on an ice flow in the arctic ocean. Symbolic for climate situation in the arctic. Symbol for endangered wildlife by global warming. The picture is taken between Spitzbergen and North pole in the arctic. It is a mother with a 1/2 years old cubs.

 

When winter settles over Canada’s coastline, the ocean’s surface can seem calm and even lifeless. Ice drifts along the shore, snow blankets the beaches where seabirds once nested, and coastal animals once searched for food. However, there is far more happening beneath the surface than meets the eye. Here is a closer look at how ocean life survives the extreme cold during the long Canadian winter.   

Adapting to Survive the Extreme Cold

How do fish survive the extreme cold? Many fish are able to adapt to colder weather. For example, Arctic cod have special antifreeze proteins in their blood that prevent ice crystals from forming. This adaptation allows them to swim freely in freezing temperatures. 

Some marine mammals have remarkable adaptations that help them survive the extreme cold. Sea otters have the densest fur of any animal on Earth. It is their main protection against the cold water they live in. Bowhead whales whales can have 43–50 cm (17–20 inches) of blubber. This blubber layer insulates them from the cold and is thicker than any other whale.   

The Great Migration: Escaping to Survive the Extreme Cold 

Many marine animals travel long distances to survive winter.  North Atlantic right whales, one of the world’s most critically endangered whales, travel from Canada to warmer waters off the southeastern United States to give birth. Their journey covers thousands of kilometres, which is a huge challenge for a critically endangered species facing threats from ship strikes and entanglements in fishing gear.    

Life Powered by Sea Ice 

Sea ice, formed by extreme cold, provides a vital habitat for many Arctic species. Microscopic algae grow on the underside, forming the base of the food chain that supports zooplankton, fish, and even polar bears. 

Sea ice also serves as a platform for marine mammals. Walruses use sea ice to rest and give birth, while polar bears rely on it to hunt seals. Countless marine species depend on sea ice to survive the extreme cold and maintain their life cycles. 

Changing Winters, Changing Oceans 

Canada’s winters are becoming increasingly unpredictable. Climate change results in warming, and the Arctic is feeling its effects fastest. Sea ice is declining rapidly. It forms later in the year and melts earlier, and Arctic waters could be almost ice-free in the summer by the 2050s.   

The loss of sea ice isn’t just an Arctic problem. It affects the entire ocean ecosystem. Shifts in ocean currents can alter migration routes and disrupt fish populations along both the Atlantic and Pacific coasts, making it harder for marine species to survive the extreme cold in changing conditions. 

Winter is a reminder that the ocean is both resilient and fragile. Life continues on and beneath the ice, adapting, surviving, and revealing how much is at stake. By protecting habitats, reducing carbon emissions, and rebuilding healthy fish populations, we can give ocean life the best chance to keep thriving and survive winter’s extreme cold conditions.