SAUL LOEB/Getty Images President Barack Obama will announce the first marine monument in the Atlantic Ocean on Thursday, building on news of last month's expansion of the largest marine reserve on the planet.

President Barack Obama will set aside a 4,900-square-mile stretch of ocean on Thursday to create the first protected marine monument in the Atlantic Ocean.

The area will be called the Northeast Canyons and Seamounts Marine National Monument and lie about 150 miles off the coast of Cape Cod in New England.

Environmentalists hailed the move, to be announced at an ocean conservation meeting in Washington, D.C., likening Obama’s efforts to those of former President Teddy Roosevelt, considered the father of American conservation.

“Teddy Roosevelt had the foresight to protect the treasures of America’s landscape,” said Rhea Suh, president of the Natural Resources Defense Council, in a statement. “With that same boldness, President Obama is conserving the crown jewels of our nation’s seascape.”

Philippe Cousteau, grandson of the famed explorer and scientist, Jacques Cousteau, called Obama’s efforts “the type of bold action our leaders must take to begin healing a resource that literally makes life on earth possible.” And others, including Collin O’Mara, president of the National Wildlife Federation, said the designation was a vital step in the protection of marine life.

“The whales, dolphins, sharks, and the many other species of fish and seabirds that rely on the Northeast Canyons and Seamounts will now have safe haven in a vibrant and globally unique wilderness,” O’Mara said in a statement.

Most commercial fishing will be immediately prohibited within the new monument, with some considerations to local lobster and crab fisheries, which will have several years to scale down operations. Many in New England had expressed their support for the protections, but some in the fishing industry had argued for more restrictions rather than a flat-out ban.

“The only user group that’s going to be negatively affected by this proposal is the fishing industry, period,” David Borden, executive director of the Atlantic Offshore Lobstermen’s Association, told The Washington Post. “Just set the boundaries deep enough so the fishing can continue.”

The oceans have become a bellwether for the fight against climate change as scientists warn of rising, warming seas devoid of life. Obama has called such changes “terrifying” and has spent his remaining days in office solidifying a science-first conservation legacy.

The Atlantic Ocean monument is the latest move in a series of major environmental efforts his administration has made. Obama announced last month the expansion of an ocean monument surrounding Hawaii that made it the largest protected marine area in the world. The area, called the Papahānaumokuākea Marine National Monument, covers some 580,000 square miles, nearly four times the size of California.

With the latest designation, the president will have increased the amount of protected ocean habitat by 20 times since he took office, The New York Times notes. He has also protected more public space than any other U.S. president.

Just 4 percent of the world’s oceans are protected, compared to about 15 percent of terrestrial regions, according to the International Union of Concerned Scientists.

The State Department will host the Our Ocean Conference in Washington, D.C., this week, with a key focus on marine protected areas, sustainable fisheries and climate-related impacts on the ocean.

UPDATE: 11:10 a.m. ― A presidential proclamation released Thursday morning offered some historical context for the new conservation efforts.

“For generations, communities and families have relied on the waters of the northwest Atlantic Ocean and have told of their wonders. Throughout New England, the maritime trades, and especially fishing, have supported a vibrant way of life, with deep cultural roots and a strong connection to the health of the ocean and the bounty it provides,” the proclamation reads. “Over the past several decades, the Nation has made great strides in its stewardship of the ocean, but the ocean faces new threats from varied uses, climate change, and related impacts.”

The AOLA, meanwhile, issued a strongly worded statement against the monument.

“We find it deplorable that the government is kicking the domestic fishing fleet out of an area where they sustainably harvest healthy fish stocks,” the group wrote. “Declaring a monument via Presidential fiat under unilateral authority of the Antiquities Act stands contrary to the principles of open government and transparency espoused by this President.”