World leaders met on France’s Atlantic coast to discuss protecting the planet’s oceans from threats such as overfishing and plastic pollution.

The One Ocean Summit comes as European authorities investigate a mass fish dumping in the Bay of Biscay which environmental activists are calling an example of abuses by huge trawlers that disrupt undersea ecosystems.

French President Emmanuel Macron initiated the three-day summit in the port city of Brest with the support of the United Nations.

“Today, we are going to make commitments,” Macron said in his opening speech.

“I am convinced they are going to help strengthen helpful actions.”

Egyptian President Abdel-Fattah el-Sissi, whose country will host the UN’s annual climate summit this year, European Commission President Ursula von der Leyen, US special envoy for climate John Kerry and several other African and European leaders attended the event in person.

Others were to take part via video messages.

Mr Kerry said “the urgency of the plight within which we all find ourselves” deserves attention.

“There are large-scale, extraordinary operations that go on every single day at sea that are indistinguishable from major criminal enterprises on land,” he said.

“They use appalling practices of labour, money laundering and fraud to destroy the good efforts of fisher people around the world who are trying to live by the rules.”

Illegal activity is estimated to account for about one-fifth of fishing globally.

Unlawful fisheries are “depleting the fish stocks of the world, literally dragging nets that we outlawed several years ago … and throwing away two-thirds of what they catch,” Mr Kerry said.

“We create marine protected areas but we don’t enforce them.”

Costa Rica, France and Britain launched an intergovernmental environmental group in 2019 to set a target of protecting at least 30% of land and sea by 2030.

The High Ambition Coalition for Nature and People now includes 83 countries.

France met its coalition commitments by extending protected areas in the French Southern and Antarctic Territories, Mr Macron announced on Friday.

Also in Brest, the United Nations cultural agency Unesco announced that at least 80% of the world’s seabeds will be mapped by 2030, compared to 20% currently.

The United States and France in a joint statement on Friday recognised “the transboundary aspects of plastic pollution and the importance of curbing it at its source.”

They said they support launching negotiations at the upcoming UN Environment Assembly to reach a global agreement addressing the issue.

“The health of our oceans is at risk,” said Nicolas Imbert, executive director of the environmental group Green Cross.

“We are already late, so we need a shock in order to have strong new commitments and also in order to meet past commitments.”

Oceans cover more than 70% of the planet’s surface.