U.N. makes a bold move to protect marine life on the high seas

The bluefin tuna is one of the biggest, fastest fishes in the ocean. Its streamlined body can sprint at up to 45 miles per hour in pursuit of its prey. Reaching some 500 pounds, this giant once dominated the Atlantic, Pacific and Indian oceans. But humans have hunted the bluefin for thousands of years. In the last century stocks have been decimated. The Pacific population is now just 2.6 percent of its original size.

Many other species that live in the high seas — the two thirds of Earth’s oceans that lie beyond national waters — are suffering a similar fate. There is no universal law protecting biodiversity. “This is a massive gap, a literal hole in the middle of the ocean,” says Lance Morgan, president of the Marine Conservation Institute, a U.S. nonprofit focused on ocean protection.

That is about to change. The United Nations is pushing to…