Author: Olive Heffernan
As the United Nations prepares a historic treaty to protect the oceans, scientists highlight what’s needed for success.In the early fifteenth century, Portuguese sailors reached a becalmed part of the Atlantic Ocean, coated with mats of gold-brown seaweed. Under windless skies, their ships drifted idly with the currents. The sailors named the seaweed Sargassum — after its resemblance to a Portuguese plant — and the region eventually became known as the Sargasso Sea.
Initially thought to be an oceanic desert, this part of the Atlantic is now recognized as a watery rainforest. It is one of Earth’s most rare and valuable marine ecosystems, so rich in nutrients that eels travel thousands of kilometres from rivers in Europe and the Americas to breed there.
But the Sargasso Sea is also one of the dirtiest and most damaged parts of the open ocean. The gyre of currents that bounds this shoreless sea entraps vast amounts of plastic waste, and fish stocks are declining in the now-busy shipping route.
Scientists want to conserve the Sargasso ecosystem, and ten governments have signed a non-binding pact to protect it. But their efforts are limited owing to a major gap in international policy. Like half of the planet, the Sargasso Sea doesn’t fall under the control of any single nation. Countries can protect or exploit waters closer than 200 nautical miles (370 kilometres) to their shorelines, but everything outside these ‘exclusive economic zones’ is considered international waters: the high seas.
The high seas make up two-thirds of Earth’s oceans, providing 90% of its available habitat for life and accounting for up to US$16 billion a year in fisheries catch. The oceans are also prime territory for the discovery of valuable mineral deposits, potent pharmaceuticals and oil and gas reserves. The United Nations Convention on the Law of the Sea (UNCLOS) regulates activities in international waters, including sea-bed mining and cable laying; a patchwork of 20 or so other organizations oversee aspects of international shipping and whaling, as well as fishing and conservation at the regional level. But no overarching treaty exists to protect biodiversity or conserve vulnerable ecosystems in the oceans.
Yet momentum is now building to protect the high seas. This September in New York City, negotiations begin on a United Nations treaty — which is likely to be an add-on to UNCLOS — to agree on how to safeguard this vast shared resource by setting aside areas for conservation and laying out rules for activities such as deep-sea mining. The treaty could also find ways to help all countries benefit from research into deep-sea species — including whether marine organisms’ genes and proteins might form the basis of new drugs or materials — either financially or through technology transfer. The talks are being heralded as a Paris climate accord for the oceans: a vital opportunity to conserve the planet’s least-explored realm. “We have a once in a lifetime chance to secure a treaty that will allow nations to manage activities on the high seas,” says Lance Morgan, president of the non-profit Marine Conservation Institute in Seattle, Washington, which is focused on ocean protection.
The UN, regional fisheries organizations and non-profit agencies have already shortlisted numerous international marine regions that — like the Sargasso — deserve protection. But researchers are unsure whether politicians will heed scientific advice in choosing what to protect, and in making judgements about environmental impacts. Ahead of the negotiations, Nature lays out this guide to protecting the high seas, and the scientific debates at play.
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Cover photo by James D. Morgan/Getty