The fate of two killer whales is uncertain following the closure of a marine zoo in France on Sunday.

Campaigners and the zoo's managers have been locked in disagreement about what should happen to the orca whales with the French government already blocking one proposal to rehome them.

Last month Marineland Antibes, located near Cannes in the French Riviera, said it would permanently shut on 5 January following new animal welfare laws.

The legislation, which bans the use of dolphins and whales in marine zoo shows, was passed in 2021 but comes into effect next year.

Marineland, which describes itself as the largest of its kind in Europe, currently keeps two killer whales - Wikie, 23, and her 11-year-old son Keijo.

Managers say shows featuring killer whales and dolphins attract 90% of Marineland's visitors – and that without it the business isn't viable.

Several destinations for the whales have been proposed but there is disagreement on where they should go and what should happen to them.

Most experts agree that releasing the two whales, which are Icelandic orcas specifically, into the wild would not be suitable as both were born in captivity and would not have the skills to survive.

"It's a bit like taking your dog out of the house and sending him into the woods to live freely as a wolf," says Hanne Strager.

In 2023 the marine biologist published The Killer Whale Journals, which details her decades long interest in the ocean predator and how they behave.

"Those whales, that have spent their entire lives in captivity, their closest relationship is with humans. They are the ones who have provided them with food, care, activities and social relations.

"Killer whales are highly social animals, as social as we [humans] are, and they depend on social bonds. They have established those bonds with their trainers … They depend on humans and that is the only thing they know."

A deal to send Wikie and Keijo to a marine zoo in Japan, backed by managers at Marineland, caused outcry among campaigners who said they would receive worse treatment.

Last November the French government blocked the deal, saying the animal welfare laws in Japan were relaxed compared to those in Europe and that the 13,000km (8,000 mile) journey would cause stress to the orcas.

Another option is to send them to a Spanish marine zoo in the Canary Islands.

Loro Parque, in Tenerife, complies with European animal welfare standards but campaigners fear Wikie and Keijo will still be made to perform there.

There have also been several orca deaths there in the last few years.

A 29-year-old male called Keto passed away in November and three other orcas died there between March 2021 and September 2022.

Loro Parque say scientific examinations of those three orcas by the University of Las Palmas de Gran Canaria show the deaths were unavoidable.

Katheryn Wise, from the charity World Animal Protection (Wap), tells the BBC: "It would be devastating for Wikie and Keijo to end up in another entertainment venue like Loro Parque – from one whale jail to another."

Wap want the orcas to be rehomed in an adapted ocean bay.

"[We and] many others have urged the government of France to do everything it can to facilitate the movement of the orcas to a sanctuary off the coast of Nova Scotia."

The organisation hoping to build the facility in eastern Canada say it would be able to attract funding if it received a commitment from the French government to send the two whales there.

The Whale Sanctuary Project (WSP) proposes to close off an area of seawater measuring 40 hectares (98 acres) with nets.

Wikie and Keijo could then use the large expanse of water, with human support from vets and welfare workers, until the end of their lives.

The average lifespan of a male killer whale is about 30 years, according to the US National Oceanic and Atmospheric Administration agency. Females usually live about 50 years.

"Life at the sanctuary will be as close as is possible to what they would have experienced growing up in the ocean," say the WSP. "It will be a new life that will make up for so much of what went before."

This kind of project has been done before.

Keiko, the orca that starred in the 1993 move Free Willy, was rescued from captivity in 1996 before being taken to a bay in Iceland in 1998.

Unlike Wikie and Keijo, he was born in the wild and was able to relearn some of the necessary survival skills while living in the bay for four years.

He eventually left with a pod of orcas he had joined and swam to Norway where he died in 2003 following an infection.

Strager warns that the proposed sanctuary might feel as alien to Wikie and Keijo as open ocean would.

"We have this conception that animals enjoy freedom in the same sense we do, 'now they are free and they will love it.'

"We don't know if they see freedom the same way ... Are they going to be scared because it is so different to what they're used to? I don't know."

She tells the BBC: "I don't think there are any good solutions for animals that have been kept in captivity their whole lives."

More than 4,000 animals will be moved out of Marineland, which was founded in 1970 by Count Roland de la Poype.

He was a decorated fighter pilot who fought during World War Two before establishing himself in the plastics industry and opening Marineland due to his interest in sea life.

The closure of his passion project is the latest step in a campaign targeting marine zoos that has gained momentum over the last 15 years.

The actress Pamela Anderson called for the closure of Marineland in 2017 and held a protest outside its entrance saying "captivity kills".

In 2013, the documentary Blackfish detailed how an orca called Tilikum killed trainer Dawn Brancheau after a show at SeaWorld Orlando in 2010.

He grabbed her and dragged her into the water where he tore off her arm and drowned her.

The film also outlines how Tilikum was also involved in the deaths of two other people.

Researchers interviewed in the film argued that orcas captured from the wild and trained to perform become violent in captivity.

Visitor numbers and financial revenues at SeaWorld suffered in the aftermath of the documentary and in 2016 they suspended their captive breeding programme.

They rejected calls to release their remaining orcas into the wild, saying they would likely die if left to fend for themselves.

Eighteen months ago they opened a new marine zoo in the United Arab Emirates, SeaWorld's first outside the US.

The new facility in Abu Dhabi is a $1.2bn (£966m) venture with state-owned leisure developer Miral and boasts the largest aquarium in the world.

There aren't any orcas on show here but, to the dismay of campaigners, dolphins still are.

Wap have helped convince Expedia not to sell any more holidays involving performances by dolphins in captivity and want other travel companies to do the same.

"Blackfish was more than a hit – it was a phenomenon," writes the scientist Naomi Rose in a report by Wap. "I am convinced it pushed western society past the tipping point on the subject of captive cetaceans."