The U.S. beat China in the overall medals race at the 2012 London Olympics, and now Americans can add another trophy to their case: A better score on ocean protection.

The U.S. scored a 63 on the new Ocean Health Index—compared with China's 53—out of a possible 100, according to a new study.

To make the index, marine scientists from a range of conservation, academic, and government institutions developed a scoring system to assess the health of the oceans, with an eye to the benefits that the seas provide to people. (Learn more about how to protect the ocean.)

Researchers evaluated ecological, social, economic, and political factors for every coastal country in the world, and then crunched the data through a computer model to get a score for each.

The world average was 60, and individual countries and territories ranged from a low of 36—Sierra Leone—to a high of 86, Jarvis Island (map), a U.S. territory in the Pacific.

A goal of the index is to help countries make more informed policy decisions, especially in those regions that have already expressed a commitment to improving ocean health, including the U.S. West Coast, Canada, Australia, and the European Union, said the study's lead author, Benjamin Halpern, a marine biologist at the University of California, Santa Barbara.

"Ocean health is a broad concept that people have a gut feeling for, but there had been no way to measure or quantify it," said Halpern, whose study was published this week in the journal Nature.

"The index helps crystallize what we know and don't know about the state of the oceans in a very broad and comprehensive way."

The Ocean Health Index was prepared by marine scientists from UC Santa Barbara's National Center for Ecological Analysis and Synthesis, Conservation International, COMPASS, the New England Aquarium, the National Oceanic and Atmospheric Administration, and several other universities. The National Geographic Society partially financed creation of the index (the Society owns National Geographic News).

Ocean Benefits for People

Halpern stressed that the Ocean Health Index is not about measuring the pristine state of a country's waters.

"Instead, we're measuring how well the ocean can deliver benefits for that place," he said.

Specifically, the index looks at how well countries score on ten goals in the waters of their exclusive economic zones, which typically stretch 200 miles (320 kilometers) offshore.

The goals include clean water, food provision, carbon capture, biodiversity, coastal protection, recreational opportunities, artisanal fisheries, support of local economies, and a "sense of place."

Halpern explained that Germany received a relatively high score of 73 even though there's a lot of industrial use of the country's waters. The key is that Germany's marine region is also well protected and provides high value to its people.

On the other hand, the uninhabited Jarvis Island scored an 86, in large part because its waters are so healthy.

Still, Halpern emphasized that the index isn't designed to make the oceans totally off-limits—it's about seeking sustainable use, he said.

"We wanted to make sure the index relates to peoples' understanding and needs and communicates to them what is otherwise a very complex issue with an enormous amount of data," he said.

Why Countries Scored Poorly

For example, study co-author Steven Katona, of Conservation International and the New England Aquarium, said that there are two ways a country can score poorly on fisheries: either by overfishing or by not fishing them as much as could be sustainably supported.

The index shows a wide range of scores among developed and developing countries. Eco-conscious northern Europe tended to score highly, while much of cash-poor and politically unstable West Africa scored poorly.

Yet the Seychelles scored an impressive 73 and Suriname earned a 69, while Singapore scored only 48 and Poland scored a dismal 42. The latter two scores were lowered by a combinations of pollution, overfishing, lack of coastal protection, and other problems.

So although financial resources and a stable government can make ocean protection easier, it's no guarantee of real-world results, the study authors say.

Halpern said that he was surprised by the overall index score of 60. He said it leaves a lot of room for improvement, yet it also shows hope in the face of gloom and doom from the advocacy community. Halpern added that positive scores can highlight things that are working and that can be replicated.

As for the 50 U.S. states, Halpern noted that high marks in certain regions, especially the West Coast, were pulled down by more troubled areas like the Gulf Coast, which haven't invested as much in ocean protection. (See more ocean pictures.)

Overall the U.S. scored well in coastal protection and coastal economics, but not as well in food supply and clean water.

Ocean Health Index to Be Valuable Tool

Juan Armando Sanchez Muñoz, who studies coral diseases at the University of the Andes in Bogotá, Colombia, was not involved in the new index but said it's "extremely useful to have such a quantitative measure of ocean health."

Muñoz, who has received funding from the National Geographic Society, said he hopes the index will become a powerful tool that pulls together such disparate issues as overfishing, mining, water pollution, ocean acidification, and more.

He added that one challenge of the index may be uneven sources of data, since many parts of the ocean are poorly studied.

"I hope the Ocean Health Index can have a way to 'learn' quickly from new sources of information and correct itself periodically," he said.

Study co-author Katona said the plan is for the index to respond to new data, and he said the scientists hope to release an updated version every year. He added that he hopes countries will add their own data into the models to get even more detailed scores.

David Gruber, a marine biologist at the City University of New York, said the index may help scientists understand how specific management decisions are having an impact.

"By mainstreaming this index and maintaining it year after year, it will provide a relative baseline and yearly checkup of the ocean's health," said Gruber, also a National Geographic Society/Waitt Foundation grantee.

Michael Lombardi, a National Geographic Explorer affiliated with the American Museum of Natural History, said the Ocean Health Index is analogous to the concept of gross domestic product (GDP).

"This type of singular measure of health—or perhaps more appropriately, 'fitness'—will certainly aid in the communication between the science community and policymakers," Lombardi, who was not involved in the index, said via email.