The United Kingdom has declared roughly 170,000 square miles around Ascension Island a marine protected area. It's one of the largest such areas in the Atlantic Ocean, and a victory for some of the world's biggest blue marlin, bigeye tuna and green sea turtles.

Earlier this month, the local Ascension government declared the scope of the marine protected area, or MPA, which forbids commercial fishing and extractive mining but allows subsistence fishing by local communities. This week, the U.K. government set aside the money needed to make that a reality.

It's a big step toward a global goal of protecting 30 percent of the world’s oceans by 2030.

Green Turtle Chelonia Mydas Green turtles were liberally harvested until 1930, but new rules helped the species rebound, and by 2014, nesting on Ascension has increased by 500%. (Photo: Kris Mikael Krister [CC BY 3.0]/Wikimedia Commons)

Ascension, one of the most remote populated places in the world, is deceivingly small, but what can be seen above water is simply the tip of a 10,000-foot underwater volcano, an area rich with biodiversity. This underwater mid-Atlantic ridge is one of the longest mountain ranges in the world, according to National Geographic. The ecosystem is home to sea turtles, marlin and is an important breeding stop for migratory birds.

"In Ascension, the U.K. has its own miniature Galápagos Islands," David Barnes, a marine ecologist with the British Antarctic Survey, told Mongabay. "Its few humans are overshadowed by thousands of land crabs, green turtles, seabirds and surrounding marine life." Barnes contributed to research underpinning the designation of the MPA.

One part of a bigger puzzle

In 2015, a grand plan was hatched to create one of the largest marine reserves in the world focusing on the waters surrounding U.K. overseas territories including Ascension and a string of islands in the Atlantic, the Pitcairn Islands in the Pacific, the British Antarctic Territory and the Overseas Territories of British Indian Ocean Territory. Aptly called the Blue Belt Programme, the goal is to protect 4 million square kilometers of marine environment around the globe.

Pitcairn Island is a volcanic island and the last British Overseas Territories in the Pacific ocean As part of the Blue Belt plan, the Pitcairn Islands were also given marine protections. (Photo: Claude Huot/Shutterstock)

One of the reasons such huge (and remote) reserves are becoming increasingly feasible is the fact that satellite technology and remote monitoring drastically cuts the cost of enforcement.

"Enforcing and monitoring these marine areas would be cost effective. The Foreign Office is at a crossroads in dealing with overseas territories. It needs to recognise that we must deal with overfishing. We now have the technological ability to do this without boats and it is much cheaper. As it is, these areas are being plundered and are not being monitored at all, even though they contain 94% of all the UK’s biodiversity," Charles Clover, chair of the Blue Foundation, told The Guardian when the idea was gaining steam.

The work is ongoing, but we think Sylvia Earle — one of the first voices calling for such protective action — would be mighty pleased.

Editor's note: This story has been updated since it was first published in March 2015.

U.K. creates one of the largest marine protected areas in Atlantic Ocean
The U.K.'s push to create new marine reserves in the Atlantic and Pacific oceans represents a victory for biodiversity campaigners. (And fish.)