A beluga whale has become stranded in France’s River Seine, as officials worry for its health in the ill-suited waters.
French rescue services spotted the protected species on Tuesday and have begun monitoring the whale with drones.
On Thursday, the mammal did not appear to move much, but has since been swimming slowly between two locks on the Seine.
Members of the public have been requested not to approach the animal, which appears to be underweight.
Speaking to Reuters agency, head of environmental group Sea Shepherd France Lamya Essemlali said: "The challenge now will be to help feed it and try to accompany it towards the ocean.”
She added that taking the whale out of the water was too risky, after failed attempts to guide it to the mouth of the river.
The officials were unsure why the aquatic mammal strayed so far from its natural habitat, almost halfway to Paris.
The L’Eure region prefecture in Normandy said in a statement that beluga whales can stray into more southern waters and temporarily survive in freshwater.
Migration from the Artic sometimes occurs in order to feed away from ice formations, but they rarely travel so far south.
Officials are concerned about the whale’s health following the death of an orca in the Seine in late May.
Although they attempted to help it back to sea, the severely ill whale died of natural causes.
In July, yet another whale, a 10-metre Minke, was found in the Seine.