© Fisheries and Oceans Canada / World Wildlife Fund Canada / VDOS Global LLC / University of British Columbia / Woods Hole Oceanographic Institution / Pangnirtung Hunter and Trappers Association and Peter’s Expediting & Outfitting Services

Features | Feb 19, 2023

Virtual whale watch #3: Overwintering in Hudson Strait

Arctic blue corridors
Bowhead whale
Canada
Shipping

Join us for a virtual whale watch over the coming months as bowhead and other whales migrate through Arctic waters and we explore what their movements are telling us. In this third watch, the bowhead whales have arrived at their winter habitat, Hudson Strait, Canada; a biodiversity hotspot for bowhead whales and other marine mammals.

After more than a 1200 km autumn migration, these bowhead whales have arrived at their winter destination of Hudson Strait in Nunavut/Nunavik, Canada, which is where they spend the winter months. While bowhead whales have started to show some flexibility in their migration patterns as the Arctic warms, Hudson Strait is a well-known wintering spot for them.

Scientists have found that Hudson Strait is a biodiversity hotspot during winter for bowhead whales and other whales, seals, walrus, and seabirds. But why Hudson Strait? As winter progresses, a perfect combination of sea ice and open water transforms this area into a habitat that the whales and other marine mammals need to live out the winter months.

As we saw in our last whale watch, the bowhead whales advanced on their migration as the sea ice advanced. Bowhead and other Arctic whales need sea ice for coverage and protection and use it as a place to rest under and hide from predators, especially since killer whales have started to make their way further into the Arctic region as sea ice diminishes with warmer temperatures.

Hudson Strait also contains polynyas, areas of open water surrounded by sea ice. As the Arctic waters are exposed to the air and natural light in polynas, the water is warmer and more biologically productive, meaning there is more food available to the animals. When it comes to Hudson Strait, scientists found that its higher productivity compared to many other areas around Hudson Bay makes this an especially important area for bowhead whales and other marine mammals in the region.

Overwintering activities

During winter, Hudson Strait’s ecosystem provides a habitat that bowhead whales need for their winter activities: feeding and mating.

Bowhead whales feed all year long, a different trait compared to their other baleen whale cousins. While there is not much research on bowhead whale winter feeding strategies, scientists know that since Hudson Strait is a productive region, bowhead whales are likely feeding throughout the winter.

During winter, bowhead whales are probably diving down into a deep trench in Hudson Strait and feeding on copepods, which are small crustaceans. Male copepods fertilize the females and then die off during the winter months. Females then survive on stored-up reserves of large fat deposits to make it through the winter. These fat females are great food for bowhead whales that rely on blubber deposits in their diet.

The winter months are also an important time for bowhead whales – mating season. Known as the jazz singers of the ocean, bowhead whales’ vocalizations are more varied and constantly change their tunes. While scientists do not know exactly why bowhead whales change their tunes so often, scientists do know that bowheads look for a mate during the winter months, and males use their songs to court a female whale.

Listen to how one bowhead male’s winter songs sounds below.

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Audio credited to:
© Stafford, K.M., Lydersen, C., Wiig, Ø. and Kovacs, K.M., 2018. Extreme diversity in the songs of Spitsbergen’s bowhead whales. Biology letters, 14(4), p.20180056.

Photo:
© Fisheries and Oceans Canada / World Wildlife Fund Canada / VDOS Global LLC / University of British Columbia / Woods Hole Oceanographic Institution / Pangnirtung Hunter and Trappers Association and Peter’s Expediting & Outfitting Services

Protecting important habitats–and their migration routes to get there

Scientists are still learning more about Hudson Strait, but one thing is irrefutable – it is a critically important winter area for bowhead whales and many other Arctic species.

Hudson Strait is also one of the few places in the Canadian Arctic where ship traffic, including icebreakers, operates throughout the winter. With the Arctic warming and sea ice melting, Hudson Strait is at risk of seeing even more shipping traffic in the future. New shipping activities would not only produce additional underwater noise already polluting the Arctic Ocean soundscape, but would also increase the chance of collisions with these slow swimming giants, as well as put this critical habitat for bowhead whales and many other Arctic animals at risk from oil spills.

WWF has already identified priority areas of conservation throughout the Arctic Ocean through ArcNet. As well as protecting this network of priority areas, our goal is that the surrounding Arctic seas are well-managed to ensure ecological connectivity at a scale that makes sense for nature. For bowhead whales, this must include protection of their important summer and winter habitats – such as Foxe Basin and Hudson Strait – and special management of the blue corridors, or superhighways, the whales use to move between them, to ensure they are safeguarded on their journeys.

WWF is working to ensure we keep the Arctic connected, for nature.

VIRTUAL WHALE WATCH

Over the coming months, we will follow several bowhead whales, as well as other types of whales, on their Arctic journey.

We are supporting the work of Dr. Steve Ferguson, a scientist with Fisheries and Oceans Canada and the University of Manitoba, and colleagues to identify important habitats for whales and the migratory corridors in the Arctic and beyond.

This research will assist WWF’s Blue Corridors conservation approach, which aims to better understand whales’ migration patterns and to inform global and regional management plans that protect them. Through understanding Arctic Blue Corridors, WWF will work to mitigate threats and provide solutions to governments and industry that will safeguard whales on their journeys.

It is widely recognised that protecting and connecting areas is key to strengthening biodiversity resilience to change, giving species and ecosystems space to adapt. At the same time, human activities and industrialisation are expanding across the Arctic. This has put biodiversity under pressure and has occupied and fragmented an increasing number of areas across the Arctic.

WWF and partners are working towards conservation goals for Arctic priority species, like bowhead whales. This includes identifying, protecting, and connecting their important current and future habitats. Following bowhead and other whales in the Arctic will help fill some current information gaps about these Arctic animals and their key habitats.

Special thanks to Foxe Basin bowhead field research team in Igloolik that deployed satellite tags onto the whales, collected photographs both from the air and boat and sampled the whales using biopsy techniques along the floe edge in June-July 2022: Cory Matthews, Justine Hudson, Tommy Pontbriand, Todd King Ammaaq, Levi Qaunaq, Travis Qaunaq, and Morgan Martin.

This project is managed by Brent Young and Steven Ferguson of Fisheries and Oceans Canada, Winnipeg. A big thank you to the Igloolik Hunters and Trappers Association, in particular the manager Jacob Maliki, for their support and assistance. Thank you as well to our Inuit colleagues based in Igloolik and Sanirayak, and to everyone who helped with truck rentals and moving gear. Financial support was provided by Fisheries and Oceans Canada and the Nunavut Wildlife Management Board.

Follow along to learn more!