OVIEDO, Spain

A fin whale with severe scoliosis was spotted off the coast of Valencia, the Oceanografic Foundation said this week.

On Saturday, the captain of a boat called an emergency line after spotting the massive creature that appeared to be tangled in a net.

Spanish police and veterinarians from the Oceanografic Foundation in Valencia rushed to evaluate the whale's situation.

They discovered that the 17-meter (55-foot) fin whale was not caught in a net but was instead “suffering from a severe deviation in its spine – a scoliosis of unknown origin that completely altered its anatomy.”

The rescue team could not manage to put a tracker on the 40-ton whale “due to its size, location and deformation,” according to a statement.

The whale swam back into the open sea within an hour of the examination. But since the whale was having trouble swimming, the Oceanografic Foundation said it could reappear in the coming days.

Whales, unlike people, are not known to develop scoliosis spontaneously. Instead, all reported cases have clear causes, most of which are traumatic injuries such as those derived from a collision with a ship, according to a 2021 study published in Nature.

Fin whales are the second-largest whale species on the planet, only after blue whales. In warmer months, they can be spotted in Spain's Mediterranean waters, according to the Oceanografic Foundation.