With the help of whale sounds, helpers try to guide an orca lost in the Seine towards the sea.

A group of scientists, police and fire brigade, among others, started the operation at the weekend near the northern French coast, as announced by the responsible prefecture of Seine-Maritime based in Rouen.

It was initially unclear whether the campaign would be successful.

"This is experimental," said bioacoustics researcher Charlotte Curé.

"We're not at all sure this will work, but it's worth trying."

There is no doubt that it is orca

According to the Marine Mammal Research Group (GEEC), the whale was first sighted in early April by the crew of a trawler about 30 kilometers off the Normandy coast.

The video recordings are clear.

There is no doubt that it is an orca.

Since then, the orca has been spotted time and time again along the coast, in the Seine estuary and even some 60 kilometers upstream in the Seine near Yainville.

Orcas are more commonly found off the coasts of Scotland, Iceland and Norway, and further south in the Atlantic Ocean in the Bay of Biscay, a GEEC expert explained.

But instead of moving towards the sea, the orca keeps swimming back and forth, the prefecture said.

The animal is extremely weak and has little chance of survival.

Because the animal is already so weak, the authorities, after consulting with experts, decided on the extraordinary noise method.

This avoids using a ship at close range, which could increase the stress level of the animal.

The whale sounds are played underwater with a loudspeaker when used.

The research teams then want to look from boats some distance away to see how the orca reacts to the sounds - whether it's attracted to them or hesitant.

So they want to try to either lure him to the sea or, as it were, drive him.

A drone also provides the scientists with photos and videos of the orca.

Why the animal appeared in the Seine is unclear.

It is speculated that the whale first strayed into the English Channel because it is ill and can feed more easily in the calmer waters there.

It may also be a young animal that has left its group and is now isolated.