Scientists have confirmed that blue whales, the largest animals on Earth, are frequenting the waters around Seychelles, a tropical island nation in the Indian Ocean.
This is a remarkable discovery, as these endangered giants were almost wiped out by whaling in the 1960s.
A safe haven for the ocean's biggest mammals
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The researchers, including scientists from the University of Seychelles, used underwater microphones to record the sounds of blue whales for a year.
They also captured footage of the whales in 2020 and 2021, which features in the Imax film Blue Whales 3D.
They found that blue whales were present in the region mainly during March and April, which coincides with the peak of the southwest monsoon.
This suggested that Seychelles may be an important breeding ground for the whales, as well as a feeding hotspot.
Dr Kate Stafford, one of the lead investigators, told BBC News: "It turns out if you stop killing animals on mass scales and you give them a chance to rebound, they can recover."
She added that Seychelles is a special place for whales and dolphins, as it is characterised by steep underwater slopes that create favourable oceanographic conditions for marine life.
"Knowing there's a population around the Seychelles is incredibly exciting," she said.
A conservation win amid global threats
The discovery, published in the Journal of Endangered Species Research, is a rare glimmer of hope for blue whales, which are still facing numerous threats from climate change, acoustic pollution, ship strikes, and entanglement in fishing gear.
Commercial whaling has had a lasting impact on blue whale numbers, which are estimated to be less than 10% of their pre-whaling levels.
More than 300,000 blue whales were killed in the southern hemisphere alone, according to figures from the International Whaling Commission.
Dr Stafford said that the recovery of blue whales in Seychelles is a "conservation win," but more research is needed to understand their population size, distribution, and behaviour in the region.
She also urged for more protection measures, such as marine protected areas and noise reduction, to ensure the survival of these majestic creatures.
One of the questions that remains unanswered is how the blue whales migrate between their summer and winter habitats.
In general, blue whale populations migrate between their summer feeding areas near the poles and their winter breeding grounds near the tropics.
There is also evidence of year-round residencies, and partial or age/sex-based migration. Blue whales are filter feeders; their diet consists almost exclusively of krill.
However, the exact routes and timing of their migrations are largely unknown, and may vary depending on oceanographic conditions and prey availability.
Some researchers have used satellite tags to track the movements of individual blue whales, and found that they can travel thousands of kilometers across oceans and continents.
For example, a study in 2015 revealed that a blue whale named Varvara migrated from Russia to Mexico and back, crossing the equator and the International Date Line, in a record-breaking journey of more than 22,000 kilometers.
Another study in 2020 showed that a blue whale named Isabela migrated from the Galapagos Islands to Antarctica and back, covering more than 10,000 kilometers in less than four months8.
These findings suggested that blue whales have remarkable navigational abilities and can adapt to changing environmental conditions.
However, they also highlight the need for international cooperation and coordination to protect these animals across their vast ranges.
