Marine experts in France have pulled a beluga whale from the Seine river in a bid to keep it alive.
The malnourished and underweight mammal swam up the river last week and the experts are hoping to save its life by moving it back into the sea.
The 13ft whale will be transported to a saltwater river basin where it will be treated by medics.
Rescuers worked for almost six hours hoisting the whale from the river using a net and crane during the early hours of the morning before placing it on a barge where it is being cared for by a dozen vets.
If the treatment at the river basin goes successfully, the whale could finally be returned to the sea.
The marine experts are attempting to transfer the 1,800lb whale to the river basin via a refrigerated truck.
The beluga was first seen in the Seine last week. While transferring the whale carries risks, Sea Shepherd, which is involved in the rescue operation, said it would not have survived in the warm, non-salty river water much longer.
"Moving it to a salt water pool will allow us to monitor it better and try and treat it," Lamya Essemlali, president of Sea Shepherd France, said of the weakened beluga.
Attempts to feed the beluga squid and live trout have failed and rescuers suspect the beluga is sick, though local
authorities said it had shown signs of improvement after receiving a cocktail of vitamins and antibiotics.
"That's what really matters: determine if it can be cured from what it is suffering from. It's a necessary step before
releasing it into the sea," Ms Essemlali told Reuters.
The beluga swam nearly halfway to Paris before local authorities confined the all-white whale in a large lock system.
It was unclear why the whale had strayed so far from its natural habitat.
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, a beluga whale was spotted in the River Thames near Gravesend in east London, for a few days, in what was then the most southerly sighting of a beluga on British shores.