First ever high-seas conservation treaty would protect life in international waters

No flag can claim the high seas, but many nations exploit them. As a result, life in the two-thirds of the oceans beyond any country's territorial waters faces many threats that are largely unregulated, including overfishing and the emerging deep-sea mining industry.

Now, nations are negotiating the first-ever high-seas conservation treaty, which the United Nations expects to finalize next year. As delegates met this week at U.N. headquarters in New York City to hash out the details, marine scientists moved to influence the outcome. One research group unveiled the results of a global mapping effort that envisions expansive new marine reserves to protect key high-seas ecosystems. Other teams are working on maps of their own using powerful modeling tools to weigh a reserve's potential for achieving key conservation goals, such as protecting important feeding grounds or helping sea life adapt to warming seas, against its economic costs.

"The policy opportunity this represents is much rarer than once in a lifetime," says marine ecologist Douglas McCauley of the University of California, Santa Barbara. Nations are asking "how we should protect two-thirds of the world's oceans, [and] it's the first time in human history that this has ever been asked."

One key issue facing negotiators—who met for the first time late last year and are scheduled to gather twice more over the next year—is how much of the high seas to protect. Existing preserves cover about 5% of the world's oceans, mostly in territorial waters. Under a different U.N. agreement, nations endorsed a goal of expanding reserves to cover 10% of the entire ocean by 2020. But many conservationists and scientists—as well as the government of the United Kingdom—argue the new pact should go bigger, placing 30% of the high seas off limits to unregulated exploitation.

Until recently, researchers lacked the data to choose which parts of the ocean to include. "If I was asked to do this 5 or 10 years ago, I would have said no," McCauley says. But now, taking advantage of a growing torrent of data from satellites, tagged animals, and survey ships as well as advances in computing power, researchers have launched at least three major efforts to show policymakers what new high-seas reserves could look like.

The tools are allowing researchers to offer answers to thorny practical questions. For example, which spawning and feeding grounds should get protection if reserves can't cover them all? And how can static protected areas address climate change, which could cause fish and other organisms to move into new areas?

The team that showed off its handiwork this week presented two possible reserve networks, one covering 30% of international waters, the other 50%. To create the maps, researchers from several universities, funded by the conservation group Greenpeace, combined biological data, such as the distribution of fish, sharks, and whales, with oceanographic information, such as the locations of seamounts, trenches, and hydrothermal vents. They identified ocean currents, potential mining areas, and biologically productive zones where deep, cold waters rise to the surface. And they located places where ocean temperatures hold steady most of the year—potential safe havens from global warming—as well as areas with large temperature fluctuations, which might harbor creatures preadapted to cope with warming.

They combined these data layers using Marxan, a program that can draw maps to maximize benefits while minimizing costs. The team also added constraints, such as requiring the program not to place the most productive fishing grounds within a reserve, and to favor networks of larger, connected reserves over smaller, isolated patches. Out of hundreds of possible configurations for the 30% and 50% scenarios, they picked the two they thought offered the best protection for biodiversity with the fewest trade-offs.

One lesson "is that protecting 30% of the area of the high seas doesn't protect 30% of the most valuable conservation features … because of the way habitats and species are distributed," says Callum Roberts, a marine biologist at the University of York in the United Kingdom and a leader of the team. Up to 40% of international waters would have to be protected, he says, to represent 30% of ecosystem types.

A second team, which includes McCauley and is funded by Pew Charitable Trusts in Philadelphia, Pennsylvania, is taking a similar approach, but its scenarios envision 10% and 30% coverage. It plans to present its maps at the next round of treaty negotiations in August.

A third team, funded by the National Geographic Society in Washington, D.C., is not limiting its mapping to the high seas and won't recommend protecting a select percentage of the ocean. Instead, the researchers will divide the entire ocean into blocks 50 kilometers on a side and rank them by conservation value. The team hopes to unveil its work early next year at the final U.N. treaty negotiations.

Some nations, especially those with large high-seas fishing fleets, will likely oppose the creation of large reserves. And even if negotiators can agree on large-scale protection, they will still face plenty of difficult issues. For example, should reserves bar all exploitation, or allow some fishing or mining, perhaps only during certain seasons? And how should the rules be enforced? Proposals to create an international body to police the high seas have already proved controversial.

Still, researchers hope their maps will encourage nations to be ambitious. "Given how fast species have declined in the last 20 years," Roberts says, "it will be a catastrophe if we can't capitalize on this momentum."