The expansion applies to some half a million square miles (1.2 million square kilometers) around the Mariana Trench Marine National Monument, areas within the Papahanaumokuakea Marine National Monument waters, and waters surrounding the Rose Atoll Marine National Monument.

They are among the ocean areas scientists recognize as "some of the most effective tools for improving ocean ecosystems and threatened fish stocks," according to the National Parks Conservation Association.

The Trump administration insists reopening these waters to commercial fishing will provide economic opportunities for the US fisherman and improve their ability to compete within the global industry.

The move follows Trump's order in April 2025 to allow commercial fishing in the Pacific Remote Islands Marine National Monument (PRIMNM), which had been created in 2009 by then-president George W. Bush, and extended by his successor Barack Obama in 2014.

And earlier this year he issued a proclamation reopening commercial fishing in protected waters off the Atlantic coast, in a region renowned for its rich biodiversity.

The Republican president, an avowed skeptic of climate change, has since his return to the White House taken aim at environmental regulations, pushing to reduce the rules' impact on business.