The largest marine protected area in the world could be created in the waters southwest of Hawaii after President Joe Biden announced his intent to create a marine sanctuary in the waters around the U.S. Pacific Remote Islands.

Biden on Tuesday said the sanctuary designation could cover 777,000 square miles of water around the Pacific Remote Islands and would be in the vicinity of seven islands and atolls: Baker, Howland and Jarvis islands; Johnston, Wake and Palmyra atolls; and Kingman Reef.

Biden was applauded when he made the announcement during his remarks delivered at the White House Conservation in Action Summit.

“That’s an area larger than Alaska and Colorado, and three times the size of Texas — that’s no small amount of land,” Biden said of the size of the proposed sanctuary. “It would make it the largest area on the planet with the highest level of protection, and it will help us meet our goal of conserving … 30% of our oceans.”

The U.S. Pacific Remote Islands waters were designated as a National Marine Monument in 2009 and expanded in 2014. A sanctuary designation could further expand the protected area by 265,000 square miles, to 777,000 square miles — the full extent of U.S. federal waters that can be protected.

The sanctuary would help Biden achieve his goal to conserve 30% of the country’s land and water by 2030.

Expansion and sanctuary designation have been advocated for by some Native Hawaiian cultural groups and conservationists. Advocates say the waters are home to dozens of endangered species of wildlife that need protecting, and reef ecosystems in the region were once important for Polynesians, Micronesians and others who voyaged across the Pacific Ocean.

U.S. Rep. Ed Case, D- Hawaii, also has long supported the sanctuary designation and expansion of the Pacific Remote Islands, and on Tuesday supported the president’s announcement.

“These waters are among the last pristine marine environments on our Earth, and also the most fragile,” Case said in a news release. “Our world’s oceans are at mortal risk, a breaking point precipitated by the unsustainable overfishing and other resource extraction, debris and land-based pollution, exacerbated and compounded by the devastating and pervasive marine effects of climate change.”

Case is a member of the U.S. House Natural Resources Committee’s Subcommittee on Water, Wildlife and Fisheries and was an advocate for creation of the Papahanaumokuakea Marine National Monument, which covers the Northwestern Hawaiian Islands.

The Western Pacific Regional Fishery Management Council, or Wespac, which covers Hawaii and other U.S. fishing regions in the Pacific Ocean, has been a staunch opponent of expanding marine protected areas.

The council isn’t convinced that the protected areas provide any conservation benefits, but they disadvantage local fishers and those employed in fishing-heavy economies in the area by restricting a growing area of ocean to fishing.

In November the council argued against a widely distributed article in the journal Science that found that the Papahanaumokuakea Marine National Monument not only protects marine life within the protected areas, but also those outside and near their borders in so-called “spillover” benefits.

Wespac’s Scientific and Statistical Committee said that it didn’t find the same increase in tuna outside the monument’s borders that the study found, setting off an argument about data collection and analysis.

The committee last week again refuted the reported benefits of marine protected areas in the Science article, and heard a presentation of a recent article finding that they produce limited benefits to tuna stocks.

The article, published in January in the Frontiers in Marine Science journal, focused on changes in tuna spawning biomass in and near the Phoenix Islands Protected Area, or PIPA, and conducted an analysis on hypothetical marine protected areas, finding “modest” benefits to tuna stocks as a result of closing areas off.

“None of the key tuna stocks in the central and western Pacific are really overfished in the first place,” said John Hampton, a tuna biology researcher and author of the article, during the committee meeting.

“It’s not really clear what threats were meant to be addressed by something like the PIPA or the 30 by 30 closures. … There aren’t very many other fisheries, and other threats, such as pollution, climate change, etc. really go unaddressed,” Hampton said.

Biden’s announcement on Tuesday gives the U.S. Secretary of Commerce 30 days to initiate a new sanctuary designation process for the Pacific Remote Islands.

The president used the summit to also announce the establishment of the Avi Kwa Ame National Monument in Nevada and Castner Range National Monument in Texas.