Governments should set a five-year deadline to crack down on over-fishing and pollution or parts of the oceans may have to be declared off-limits to industrial fishing, an expert commission said on Tuesday.
The Global Ocean Commission, a group of senior politicians formed in 2013, urged rescue measures including a phase-out of damaging subsidies for fishing fleets and tougher regulations on offshore oil and gas to limit pollution of the high seas.
"The oceans are a failed state," David Miliband, a former British foreign secretary and a co-chair of the commission, told Reuters in a telephone interview. "A previously virgin area has been turned into a plundered part of the planet."
The report said that many fish stocks in the high seas - an area outside national coastal zones that covers almost half the globe - were under pressure from illegal and unregulated catches.
About 10 million tonnes of fish worth $16 billion, from tuna to molluscs, are caught every year in the high seas out of a global fish catch of 80 million tonnes, the commission said.
It called for a five-year rescue package to tackle threats from over-fishing to pollution. If that did not work, governments should "consider turning the high seas ... into a regeneration zone where industrial fishing is prevented," it said.
Management consultants McKinsey and Co. have estimated that the economic cost of closing the high seas to fishing would be $2 per each person on the planet. But closure would be beneficial by causing a $4 rise in fish yields in coastal regions.
Professor Callum Roberts, a marine expert at York University in England, welcomed the commission's recommendations as a spur for action but cautioned of many past failures to save the seas.
And he said it was disappointing that the Commission was recommending waiting five years before considering regeneration zones. "We need them right now ... a call for a total ban on high seas fishing would be entirely justified," he said.
As part of global efforts to protect the seas, US secretary of state John Kerry called last week for a global regime to protect the oceans.
"The ocean provides 50 percent of our oxygen and fixes 25 percent of global carbon emissions. Our food chain begins in that 70 percent of the planet," said Jose Maria Figueres, former Costa Rican President who is co-chair of the Commission.
"A healthy ocean is key to our well-being," he said in a statement. The Commission said fishing subsidies totalled at least $30 billion a year and urged a phaseout of damaging support.
"Consumers are paying twice for every fish they eat: once through their taxes and the second time at the market," it said.
Japan, South Korea, Taiwan, Spain, the United States, Chile, China, Indonesia, the Philippines and France are the main high seas fishing nations.
The Commission urged tougher environmental and safety standards for oil and gas. "A third of all oil is now extracted from under the seabed with some wells deeper than 3 km (2 miles) below the surface," it said. And trawlers were able to scour the ocean floor down to depths of 2,200 metres.