Watch viral video of giant humpback breaching surface of sea

The four-meter (13-foot) cetacean was found a week ago and appeared sick and underweight. However, marine specialists say it is in "satisfactory" condition.

The endangered species known as the beluga cannot endure long in fresh water. At Saint-Pierre-La-Garenne in Normandy, the mammal is currently around 130 kilometres (80 miles) inland from the English Channel. As Seine's banks are inaccessible to vehicles, therefore all work will have to be done by hand.

Officials warn that attempts to "nudge" the whale back toward the sea are ineffective because it is caught behind a lock and unable to go further inland. The beluga is currently about 80 kilometres from the French capital. The plan is to transport it by road to an unidentified ocean basin.

The difficulties are enormous, and the distance is likely to add to the stress of an 800-kilogram animal (nearly 1,800 pounds). During the transfer, veterinarians will keep continual watch. A request for donations of heavy-duty ropes, nets, mattresses, and other equipment has been made by Sea Shepherd. The nearest beluga population is 3,000 kilometres from the Seine, off the Svalbard archipelago, north of Norway.