A beluga whale that was stranded for several days in the Seine river in France has died after being hauled out in the early hours of Wednesday in an attempt to save its life.
Experts had said the starving mammal could die in the risky operation in which it was loaded on to a lorry and driven to a saltwater basin in Normandy, northern France.
"We regret to announce the death of the beluga whale, despite an unprecedented operation to try to save it," said officials from the Calvados region.
Rescuers had hoped to return the whale to the sea after treating it in the basin.
The whale was lifted from the river with a net and crane in the early hours of Wednesday and placed on a barge under the immediate care of a dozen vets.
The dangerously emaciated marine mammal had no digestive activity for unknown reasons, conservation group Sea Shepherd France tweeted, saying veterinary examinations were made after the beluga was hauled out of the water.
The extraction of the 800-kilogram animal took six hours.
The all-white beluga had travelled nearly halfway to Paris before local authorities were able to confine it in a large lock system. It was transported in a refrigerated lorry to the coastal town of Ouistreham, Normandy.
Photos posted by Sea Shepherd France showed the white mammal lying on a large net that was used to get it out of the river lock.
A team of vets had planned to take the four-metre whale to a coastal area of Ouistreham for “a period of care”, according to Lamya Essemlali, president of Sea Shepherd France.
Despite the success of the first stage of the rescue operation, there were doubts about the chances of survival for the whale, which should normally weigh 1,200kg.
"The veterinarians are not necessarily optimistic concerning the beluga's health," Isabelle Dorliat-Pouzet, secretary general of the Eure prefecture, told BFM TV.
"It's horribly thin for a beluga and that does not bode well for its life expectancy for the medium term," she said.
"We are awaiting the results of the blood test and the ultrasounds and, depending on the results, a decision will be made whether or not he should take the road to the sea," she told a press conference by the river just an hour after the whale was pulled out.
"As I speak to you, he is alive, he is on the barge, he survived. He is being treated," Ms Dorliat-Pouzet said.
"We could see that he is a male, that he is very underweight and that he has a few sores," she said.
In late May, a gravely ill orca swam dozens of miles up the Seine and died of natural causes after attempts to guide it back to sea failed.
In September 2018, for a few days a beluga whale was spotted in the River Thames near Gravesend, east of London, in what was then the most southerly sighting of a beluga on British shores. The whales typically live in pods in Arctic coastal waters.