PARIS — French environmentalists are working around the clock to try and feed a dangerously thin Beluga whale that has strayed into the Seine River. So far, they have been unsuccessful.

Marine conservation group Sea Shepherd France tweeted Saturday that “our teams took turns with the Beluga all night long. It always ignores the fish offered to him.”

The lost Beluga was first seen in France’s river, far from its Arctic habitat, earlier this week. Drone footage subsequently shot by French fire services showed the whale gently meandering in a stretch of the river’s light green waters between Paris and the Normandy city of Rouen, many dozens of kilometers (miles) inland from the sea.

Conservationists have tried since Friday to feed a catch of herring to the ethereal white mammal. Calling it “a race against the clock,” Sea Shepherd fears the whale is slowly starving in the waterway and could die.

Authorities in the l’Eure region said in a Friday night statement that the wild animal has a “fleeing behavior vis-a-vis the boats” and has not responded to attempts to guide it to safer waters.

The people trying to help the whale are being as unobtrusive as possible to “avoid stress that could aggravate his state of health,” according to the statement.