Campaigners have called for the Sargasso Sea to be fully protected as an ocean sanctuary as Britain has signed a global High Seas Treaty into law.

The call was also made for Bermuda to secure “a vital role” in managing the marine haven, and for the Government to work with Britain for the protection of the ecosystem.

Britain ratified the landmark treaty, intended to help protect two thirds of the world’s oceans, last month.

Also known as the Biodiversity Beyond National Jurisdiction Agreement, the treaty could not be ratified independently of Britain by Bermuda.

Noelle Young, a local environmental campaigner who has been advocating for inclusive implementation of the treaty for Bermuda, said its success will not be measured solely by the number of protected areas.

Ms Young said: “It will rightly be measured by the recovery of whales, sharks, seabirds, turtles, fish and countless other species.

“But we should not forget that the people of small-island communities are part of that biodiversity too.

“Nowhere is that more evident than in the tiny island of Bermuda, where the health of the Sargasso Sea and the wellbeing of our people are inseparable.

“The people who call these oceans home hold centuries of knowledge that cannot be found in scientific journals alone.

“Global decision-makers have a responsibility to listen, learn and ensure that our knowledge helps shape these new international ocean policies. Our goal is the same: a thriving ocean.

She said the treaty gives global leaders an opportunity to protect one of the world's most remarkable marine ecosystems.

It also gives them a chance to demonstrate “that truly sustainable conservation can only be achieved when international policy and human rights are allowed to advance together”.

Ms Young added: “Bermudians are not asking to stand in the way of conservation — we are inviting leaders to share their privilege, so that together we can build stronger international ocean policy to protect the Sargasso Sea that we call home.”

Chris Thorne, Greenpeace UK oceans campaigner, called on British prime minister Andy Burnham to “seize the opportunity” that the treaty brings.

He also urged Mr Burnham to champion bold proposals to protect vast swaths of the Atlantic Ocean — including the Sargasso Sea — as part of a promise to conserve 30 per cent of land and sea by 2030.

Mr Thorne said: “Greenpeace has been collaborating with environmental groups, scientists, fishers and politicians in Bermuda, the islands of which are surrounded by the Sargasso Sea.

“This uniquely biodiverse part of the Atlantic Ocean must be prioritised as one of the first ocean sanctuaries under the treaty, free from all destructive industrial activity, and Bermuda should have a vital role in managing the sanctuary.

“We must ensure protection for the Sargasso’s precious sea life, including whales and other important migratory species.”

The Sargasso Sea Advisory Council — which was set up and chaired by Ms Young — has been established to campaign for lasting international protection for the Sargasso Sea.

It will also ensure the island has a direct, formal voice in how the ecosystem is governed.

Campaigners noted potentially significant environmental, social and economic benefits to Bermuda of a Sargasso Sea Ocean Sanctuary.

However, they said as Bermuda is an Overseas Territory, it does not have a direct voice in the United Nations, and called on Britain “to take the cause forward” on the global stage.

It was noted that biodiversity is in “steep decline”. With less than five years left on the clock to protect at least 30 per cent of land and sea for nature by 2030, the race is on to meet the target.

Campaigners also urged governments to “mobilise swiftly” and to develop proposals for new high-seas sanctuaries, including the Sargasso Sea, over the next six months before the first ocean Conference of Parties in January 2027.

“These areas must be fully or highly protected to ensure that vast areas of the ocean are closed to extractive and destructive human activities, unlike many current marine protected areas, including those in the UK, which are protected in name only,” the campaigners said.

They said governments should ensure that the development of sanctuaries is based on robust scientific evidence.

It should also be done with participation from indigenous peoples and local communities to ensure the process is both driven by science and is socially just.