The White House is preparing to expand protections for a swath of the Pacific Ocean that would bar energy development, fishing and other activity in the area.

The epicenter is the Pacific Remote Islands Marine National Monument, a marine sanctuary designated in 2009 by former President George W. Bush, in the south-central Pacific Ocean. While Bush used the Antiquities Act of 1906 to declare the monument, the White House said the Obama administration hasn't decided the mechanism for the potential expansion.

The White House said the protections would help revitalize overfished populations, such as tuna, and preserve coral reef vital for marine life. The push comes as House Republicans have sought to reduce funding for the National Oceanic and Atmospheric Administration's fisheries management and climate change monitoring efforts.

"These tropical coral reefs and associated marine ecosystems are also among the most vulnerable areas to the impacts of climate change and ocean acidification," said the White House, which announced several other ocean-related initiatives and portrayed them as an extension of President Obama's climate strategy.

The White House hasn't decided how much to expand the monument, which currently covers nearly 87,000 acres. It will decide the scope by the end of the year after receiving input from commercial fishermen, scientists, lawmakers and conservation experts, and then open the proposal to a public comment period.

The move builds on Obama's pledge to conserve more land through executive action — last month he declared 500,000 acres of the Organ Peaks-Desert Mountains region in New Mexico a national monument, the largest such designation of his presidency.

GOP lawmakers, however, bashed the effort as an example of regulatory overreach that would spurn energy development and commercial fishing.

“For years the Obama administration has threatened to impose ocean zoning to shut down our oceans, and today the president is making good on that threat. This is yet another example of how an imperial president is intent on taking unilateral action, behind closed doors, to impose new regulations and layers of restrictive red tape," said House Natural Resources Committee Chairman Doc Hastings, R-Wash.

The currently protected region is 50 nautical miles from Howland, Baker and Jarvis islands, the Johnston, Wake, and Palmyra atolls and Kingman Reef. It is densely populated by fish and thousands-year-old coral reefs put at risk by ocean acidification, and is a key habitat for sea turtles, dolphins, whales, pearl oysters, giant clams and other marine life.

Positioning the effort within the president's climate change strategy, the White House released a report on the effects of ocean acidification, which is caused by carbon dioxide emissions from burning fossil fuels.

The report noted that the ocean absorbs roughly one-quarter of man-made emissions annually, making water more acidic and more harmful to certain fish, shellfish and plants. It noted that pH levels, which measure acidity, are changing at 50 times faster than historical rates, endangering maritime economic activity that contributed $258 billion to the country's gross domestic product and 2.8 million jobs in 2010.

"[T]here is every reason to believe that acidification of this pace and magnitude would severely impact a number of important types of marine life; the extent to which ocean life as a whole could adapt to such changes remains unclear," the report said.

The focus on ocean acidification, fisheries management and coastal resilience -- the Interior Department on Monday announced a $102 million grant program for restoring Atlantic Coast flood plains and other natural barriers to buffer communities against extreme weather and rising sea levels -- comes as the Senate is moving to restore funding the House stripped for such programs through NOAA in the Commerce, Justice and Science Appropriations Act of 2015.

The White House also said it would begin combating fraudulent fish labeling and black market sales.

Ocean conservation group Oceana, which published a 2013 report that found 33 percent of fish is mislabeled — with red snapper and tuna being mislabeled 87 percent and 59 percent of the time, respectively — praised the news.

“President Obama’s announcement is a historic step forward in the fight against seafood fraud and illegal fishing worldwide. This initiative is a practical solution to an ugly problem and will forever change the way we think about our seafood," said Beth Lowell, the group's campaign director.