The speed at which the high seas have been depleted of some of their most spectacular and iconic wildlife has taken the world by surprise.
A network of marine reserves could be rolled out across the high seas to protect wildlife hotspots and save species from extinction, a report has said.
The study by academics at York and Oxford universities in collaboration with Greenpeace maps out how to protect at least 30 percent of international waters, a target scientists have said is needed to conserve wildlife and tackle climate change.
The high seas, areas of ocean outside national waters, cover more than two-fifths of the Earth's surface and are home to an array of life which rivals that found in coastal areas or on land.
Biological processes by ocean creatures which see carbon captured at the surface of the sea and stored deep below also play an important role in reducing carbon dioxide in the atmosphere.
But the report warns the global oceans are at risk from fishing, the emerging threat of deep seabed mining, climate change warming the seas while carbon emissions are making them more acidic, and plastic and other pollution.
Negotiations at the United Nations (UN) towards a new global ocean treaty could pave the way towards protecting vast swathes of seas outside national borders totalling 230 million square kilometres, the study said.
It breaks down the global oceans into 100 kilometre squared units and maps the distribution of wildlife and habitats such as sharks, whales, seamounts or underwater mountains and hydrothermal vents which support unique nature.
It modelled the best way to fully protect 30 percent or 50 percent of the global oceans to ensure hundreds of important conservation features are protected in the most efficient way while minimising impacts on human activity such as fishing.
The most efficient design included existing high seas marine protected areas in the Southern Ocean and North Atlantic and vulnerable areas closed to fishing by regional fisheries management organisations.
The designs only displaced around 20 percent or 30 percent of existing fishing activity, showing that networks which cover the full range of wildlife and habitats can be created with limited economic impact, the report said.
Professor Callum Roberts, marine conservation biologist at the University of York, said: "The speed at which the high seas have been depleted of some of their most spectacular and iconic wildlife has taken the world by surprise.
"Extraordinary losses of seabirds, turtles, sharks and marine mammals reveal a broken governance system that governments at the United Nations must urgently fix.
"This report shows how protected areas could be rolled out across international waters to create a net of protection that will help save species from extinction and help them survive in our fast-changing world."
Louisa Casson, Greenpeace UK campaigner, said: "Over the next 18 months, governments around the world have a unique opportunity to establish a global framework for protecting the oceans.
"By working together they can facilitate the protection of 30% of the world's oceans by 2030, via a network of fully protected ocean sanctuaries.
"UK ministers like Michael Gove and Jeremy Hunt need to take the lead and personally engage with their counterparts to encourage international collaboration and high ambition to protect the oceans for future generations."
The report has been welcomed by Environment Secretary Michael Gove, who said: "From climate change to overfishing, the world's oceans are facing an unprecedented set of challenges.
"It is now more important than ever to take action and ensure our seas are healthy, abundant and resilient.
"The UK is already on course to protect over half of its waters, and I join Greenpeace in calling for the UK and other countries to work together towards a UN High Seas Treaty that would pave the way to protect at least 30% of the world's ocean by 2030."
Emily Beament is environment correspondent for the Press Association.