President Barack Obama will expand the Papahanau- mokuakea Marine National Monument by hundreds of thousands of square miles, creating the world’s largest marine reserve and permanently protecting coral reefs and deep-sea marine habitats from activities such as commercial fishing and mineral mining, the White House announced Thursday.

The designation will quadruple the size of the current protected area surrounding the uninhabited Northwestern Hawaiian Islands, which was designated a national monument by George W. Bush in 2006.

The White House also announced that Obama will address the World Conservation Congress in Honolulu on Wednesday. The conference, which is being held in the United States for the first time, is expected to attract as many as 10,000 people, including government dignitaries, scientists, environmentalists and business leaders.

The conference will focus on the climate crisis, the unprecedented rate at which species are becoming extinct and the effects that damaged ecosystems are having on the world’s economies.

Obama will then travel Thursday to Midway Atoll, located within Papahanau- mokuakea, to mark the significance of the monument expansion and “highlight first-hand how the threat of climate change makes protecting our public lands and waters more important than ever,” according to a White House press release.

“It is now fair to say that the president has as strong as an environmental legacy and track record as any president in generations,” U.S. Sen. Brian Schatz, who was singled out by the Obama administration as playing a crucial role in the president’s decision, told the Honolulu Star-Advertiser.

Obama’s decision follows months of debate in Hawaii between the longline fishing industry, which has opposed the expansion, and the plan’s supporters — a long list of local lawmakers, hundreds of scientists and environmental organizations including The Pew Charitable Trusts.

In addition to members of the longline fishing industry, the proposed expansion has been opposed by former U.S. Sen. Daniel Akaka and former Hawaii Gov. George Ariyoshi, as well as more than two dozen state lawmakers, including House Speaker Joe Souki and Senate President Ron Kouchi. Kouchi later changed his position to support expansion.

Opponents of the expansion argued that it would negatively affect Hawaii’s fishing industry, potentially driving up local fish prices and increasing imports. At a protest rally at the Capitol last month, critics also argued that the federal government shouldn’t be dictating what happens in local waters.

“The ocean belongs to us,” Ariyoshi told the media at the rally. “We ought to be the ones who decide what kind of use to make of the ocean. And we don’t want someone from the outside to come, or people from the outside to come, and tell us how to live with the ocean.”

The federal government has long had jurisdiction over the area that will be protected, however, and the idea of expanding the monument has had local backing.

In January prominent Native Hawaiian leaders sent Obama a letter proposing the idea, arguing that the waters surrounding the Northwest Hawaiian Islands contained sharks and large, predatory fish that have been heavily overfished elsewhere and were in need of protection.

The letter was signed by William Aila, deputy director of the Department of Hawaiian Home Lands; Nainoa Thompson, president of the Polynesian Voyaging Society; and Kamanaopono Crabbe, head of the state Office of Hawaiian Affairs, among others.

Schatz said the rhetoric for and against expansion had grown heated in recent weeks and that he hoped both sides could now work toward finding common ground.

“We are quite confident that this is in the best interest of not just the ecology of the Pacific Ocean, but our ability to catch and eat fish going forward,” he said. “This is not a situation of whether we want to catch fish or look at fish. It’s about making sure the ocean is sustainable for generations to come.”

U.S. Sen. Mazie Hirono also issued a statement congratulating the president for his leadership in protecting ocean resources.

“President Obama’s efforts to enhance protections for our ocean ecosystem will help to combat climate change, preserve biodiversity and honor cultural traditions,” Hirono wrote. “As part of his announcement, I appreciate the president’s recognition of the importance of commercial fishing to Hawaii’s way of life and our shared goal of supporting Hawaii’s sustainable pelagic fisheries.”

Obama will expand the protected area around the Northwest Hawaiian Islands using the Antiquities Act of 1906, which affords him unilateral power to designate U.S. lands and waters as national monuments.

Specifically, the monument will be expanded to 582,578 square miles — an area about twice the size of Texas — from 139,800 square miles. The expansion is expected to provide critical protections for more than 7,000 marine species, including endangered whales and sea turtles, and black coral, which is believed to be the longest-living marine species in the world, capable of surviving for more than 4,500 years, according to the White House.

Commercial fishing and mineral extraction will be prohibited in the monument area. However, recreational fishing, removal of fish and other resources for Native Hawaiian cultural practices and scientific research will be allowed in the area by permit. The originally proposed boundaries of the monument have also been pushed back around Kauai and Niihau to ensure that small-boat fishermen can still fish in the nearby waters.

Federal agencies will also sign an agreement with Hawaii’s Department of Land and Natural Resources and Office of Hawaiian Affairs that will provide the state agencies with a greater management role in the area.

As “ocean acidification, warming and other impacts of climate change threaten marine ecosystems, expanding the monument will improve ocean resilience, help the region’s distinct physical and biological resources adapt and create a natural laboratory that will allow scientists to monitor and explore the impacts of climate change on these fragile ecosystems,” the White House said in its press release.

Obama’s decision came on the heels of an announcement by Gov. David Ige that after listening to both sides of the debate, he supported expanding Papahanaumokuakea.

“You may be familiar with the Hawaiian proverb, E ola ke kai, e ola kakou — as the ocean thrives, so do we,” Ige wrote in a letter to Obama on Wednesday. “This proposal strikes the right balance at this time for the waters surrounding the Hawaiian Islands, and it can be a model for sustainability in the other oceans of planet Earth.”