A fin whale with a severely deformed spine was recently filmed struggling to swim off Spain’s Mediterranean coast. This extreme case of scoliosis was likely caused by a ship collision and is likely to slowly starve the gentle giant to death, experts say.
The injured 17-meter fin whale (Balaenoptera physalus) was spotted on March 4 by the crew of a boat off a beach at Cullera near Valencia. The captain of the boat thought the whale was caught in a fishing net and alerted the Spanish Guardia Civil, who sent a team of biologists and veterinarians from the Oceanographic Valencia aquarium. After arriving at the scene, it became clear that the whale was not trapped; Instead, it had “scoliosis of unknown origin,” according to one Facebook message (opens in new tab) of Oceanographic Valencia.
The researchers tried placing a tracking device on the injured animal’s back, but it was too deformed to successfully attach the satellite tag. After “a few hours of attention,” the fin whale slowly drifted away from shore and into deeper waters where it disappeared from view, Oceanographic Valencia representatives wrote.
Experts told Live Science that the scoliosis was likely caused by a ship collision that broke the whale’s back.
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“The term scoliosis simply refers to an abnormal lateral curvature of the spine,” Jens Currie (opens in new tab), chief scientist for the Pacific Whale Foundation in Hawaii, told Live Science in an email. “The cause of scoliosis can take many forms, but the most common is blunt trauma.”
It’s likely the whale was “recently struck by a vessel,” Currie said, a view shared by Eric Hoyt (opens in new tab)a research fellow at Whale and Dolphin Conservation (WDC) in the UK, and Simon Panigada (opens in new tab), vice president of the Tethys Research Institute in Italy. But the experts also noted that it’s hard to know exactly what happened.
It is possible for large whales to be born with scoliosis or develop it in their early years. But young whales that develop scoliosis almost never reach adulthood, Currie said.
Baleen whales – a group that includes fin whales, blue whales (Balaenoptera musculus), humpback whales (Megaptera novaeagliae) and others – feed by jumping through large schools of small crustaceans known as krill. To do this, they rely on their huge tails, or flukes, to propel themselves quickly through the water. But according to the footage, the injured whale can’t do this, meaning it’s probably starving.
“We can see on the video that the whale is already very thin and looks unhealthy,” Currie said. “It’s very unlikely to survive.” Baleen whales can survive for many months without eating properly, meaning such injuries can lead to a “slow and painful death,” he added.
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This is not the first case of whale scoliosis due to ship strikes. In December 2022, a humpback whale named Moon was spotted in Hawaii with a broken back, after swimming more than 3,100 miles (5,000 kilometers) from British Columbia, Canada using only her webbed feet, according to The protector (opens in new tab). Last year, Panigada spotted another fin whale with scoliosis near Barcelona, although the spinal deformity was less severe.
But most whales do not survive an encounter with a vessel. Overall, about 20,000 whales are estimated to be killed each year by ship strikes, due to a more than 300% increase in global shipping traffic since 1992, according to Friend of the sea (opens in new tab), a non-governmental organization based in Italy. But it’s hard to track this because strikes often go unreported and most whales killed will never be found, Hoyt said.
In addition to ship strikes, whales are also exposed to significant shipping noise that can disrupt their navigation, feeding and communication. “I would say so [ship traffic] is one of the biggest problems facing cetaceans worldwide,” said Currie.