President Obama announced Tuesday afternoon his intentions to protect ocean ecosystems supporting coral reefs, whales, sea turtles and other at-risk species by expanding a marine sanctuary in the remote central Pacific Ocean.

The executive order would ban fishing, energy exploration and other activities and create the world’s largest marine sanctuary and double the area of ocean globally that’s fully protected. It’s expected to undergo a comment period and then go into effect later this year. Obama has used his executive authority under the Antiquities Act of 1906 to create 11 new national monuments on millions of acres of land, which banned some industry operations like oil and gas drilling.

The move is expected to upset U.S. tuna fishermen who work in the region. Fish caught in the area account for about 3 percent of the yearly U.S. tuna supply from the western and central Pacific, according to the Pew Charitable Trusts.

Obama also asked federal agencies at the State Department’s oceans conference happening this week to develop programs to reduce seafood fraud and the global black market for fish trading.

“Growing up in Hawaii, I learned early to appreciate the beauty and power of the ocean,” Obama said at the White House event. “And like Presidents Clinton and Bush before me, I’m going to use my authority as president to protect some of our most precious marine landscapes, just like we do for mountains and rivers and forests.”

Former President George W. Bush created the marine sanctuary Obama wants to enlarge to about the size of Texas. The Pacific Remote Islands Marine National Monument, as the area is known, would expand from its nearly 87,000 square miles to nearly 782,000 square miles that includes seven uninhabited islands.

White House officials told the New York Times they had not yet determined the borders of the new sanctuary and will spend the next few months reviewing comments from groups including environmentalists, fishers and elected officials before making the final plan.  

Last week during Capitol Hill’s “Ocean Week,” the Obama administration finalized a rule that allows the public to nominate new marine sanctuaries off U.S. coasts and in the Great Lakes.