Paris: Experts in France have launched a last-ditch attempt to save a stranded beluga whale by injecting it with a vitamin-infused dart to entice it to eat.

Time is running out for the emaciated whale, which appeared in the River Seine around a week ago. First seen on August 2, the animal is about 70 kilometres from Paris, far from its natural habitat of arctic waters.

The vitamin dart was used after efforts to strengthen the starving animal with frozen herring and live trout failed as it showed no interest. The injection also contained antibiotics and an appetite stimulant.

“He has to be moved in the coming 24 to 48 hours; these conditions are not good for him,” Lamya Essemlali, head of the marine conservation group Sea Shepherd France, told AFP on Sunday.

Experts have also considered the possibility of opening up the locks and leading the animal 160km back out into the open sea.

The locks were closed at the request of Sea Shepherd France, which has been tracking the whale, to prevent it from swimming further inland. But the longer it stays in stagnant freshwater, the less likely the whale will be able to make the long and exhausting journey.

“We are doubtful about its ability to return to the sea,” she said. “Even if we drove it with a boat, that would be extremely dangerous, if not impossible.”

On Sunday, Sea Shepherd France issued a new update on Twitter, saying that while the severely underweight animal continues to reject food, it is alert and dynamic, and that euthanasia would be premature.