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Whales on the move: mapping threats and solutions for our ocean giants
© F.Bassemayousse / WWF France
Mother sperm whale and her offspring.

Whales undertake some of the most extensive  migrations on earth, often swimming many thousands of miles over many months, along the coast, but also across the open ocean, in and out of international and national waters. These “Blue Corridors” – portions of sea that whales cross in their migration – are essential for their survival, allowing them to move between critical ocean habitats where they feed, mate, give birth, nurse their young, and socialise. 

Throughout the Southern Hemisphere, humpbacks make seasonal migrations between the tropics and polar waters, moving along the coasts through the waters of 28 countries and the open ocean that lies beyond the jurisdiction of any nation. Along the coast of South America, scientists tracked one humpback whale travelling 18,942 km over 265 days, from its summer foraging area near the Antarctic Peninsula, up to its winter breeding area off Colombia and back to the Antarctic Peninsula.

But the growing dangers whales are facing worldwide along these epic journeys are signs of an ocean that is seriously under threat. These dangers connect us all and  highlight the need for joint urgent protection where it matters most.

Mapping whale superhighways
"Protecting Blue Corridors", a new report by WWF and our science partners, has managed to visualise for the first time the satellite tracks of over 1,000 migratory whales worldwide. The report identifies where these migratory routes and key habitats overlap with the emerging and cumulative impacts of activities (e.g. fisheries, maritime traffic, energy developments) and where increased protection is crucial. As many as 300,000 whales, dolphins, and porpoises are killed every year from entanglement in fishing gear. 

Ever-expanding shipping traffic is leading to more collisions between whales and ships and is more than doubling underwater noise pollution each decade. Climate change is shifting whales’ prey populations, especially in the polar regions – making it harder for them to find food. Eight million tonnes of plastic enter the sea every year: that’s about one full garbage truck every minute. New research shows that whales near large cities ingest around three million microplastics per day.

Even after decades of protection from commercial whaling, the impact of human activities at sea is so big that six out of the 13 great whale species are now classified as endangered or vulnerable by the International Union for Conservation of Nature (IUCN). The critically endangered North Atlantic right whale, a species that migrates between Canada and the United States, has reached its lowest point in 20 years – numbering only 336 individuals. It's clear that a new conservation approach is needed to address these mounting threats and safeguard whales, through enhanced cooperation from local to regional to international levels.

The benefits of protected blue corridors extend far beyond whales. Growing evidence shows the critical role whales play in maintaining ocean health and our climate: throughout its life, one whale captures the same amount of carbon as thousands of trees, and along its migration route, its faecal plumes fertilise marine ecosystems boosting phytoplankton production – microscopic plants that capture an estimated 40% of global carbon emissions and produce over half of the world’s oxygen.

This means that by restoring whale populations, we can help restore ocean ecosystems and mitigate and build resilience to climate change. It’s helping nature help itself, and all of us who depend on it.

Mediterranean Whales
The Mediterranean Sea is home to eight cetacean species, including fin, sperm and long-finned pilot whales along with short-beaked common dolphins and bottlenose dolphins, and a full range of human pressures. Two main “Blue Corridors” that require increased protection can be identified, one  in the northwest Mediterranean  which hosts an exceptional diversity and abundance of marine species, the other in the Hellenic Trench – a core feeding, breeding and migrating habitat for several marine species, including the endangered Mediterranean sperm whale and Cuvier’s beaked whale.

Despite their high conservation value, both areas are subject to intense shipping traffic, resulting in high risk of collision. Collisions with cetaceans increase the risk of death or injury to both people and animals and can cause damage to vessels, including to hulls, propellers, shafts, rudders and key logging or sensing equipment such as sonar domes. In addition, underwater noise – generated from a range of sources, including maritime traffic and seismic exploration in the Hellenic Trench – is a growing threat to the health and well-being of marine mammals and other marine species. It’s time for action to protect blue corridors for whales, our ocean, and ourselves.

As our understanding of whales’ migratory routes and the threats they face evolve, our approach to conserving and restoring whale populations across their entire range must also evolve. This means increasing cooperation between researchers, local communities, national and international institutions, governments, and industries to build and implement an effective network of marine protected areas, taking action to reduce the impact of human activities by avoiding bycatch, reducing marine litter, and managing maritime traffic and integrating whale protection into biodiversity and climate policies and investments. 

Together, we can protect our ocean giants and make their epic journeys safer for years to come.