On Monday, President Obama is expected to declare hundreds of thousands of square miles of tidal waters in Maryland and Wisconsin as marine sanctuaries, protected from fishing and other commercial activities.
These are the first US waters to be newly designated as sanctuaries in 15 years.
Top officials, including US Secretary of State John Kerry, will make the commitment today at the international conference on marine protection, called "Our Ocean," in the Chilean port city of Valparaiso. Several other nations here will also outline plans for tracing seafood imports to combat overfishing and water pollution.
Chile today is expected simultaneously announce the creation of the third-largest protected marine zone in the world, according to environmental advocates, blocking off the waters off Easter Island, which is known for its hundreds of human statues carved out of volcanic rock. The country is expected to protect more than 200,000 square miles of the South Pacific Ocean from commercial fishing and oil and gas exploration.
The Obama administration’s plan for the United States involves an 875-square-mile area of Lake Michigan that extends from Port Washington to Two Rivers. It contains a collection of 39 known shipwrecks, 15 of which are listed on the National Register of Historic Places.
In Maryland the Mallows Bay-Potomac River will earn protection today. It encompasses a 14-square mile area of the tidal Potomac River next to Charles County, home to nearly 200 vessels, some from the Revolutionary War. They are found in a largely undeveloped area that serves as habitat for endangered species of wildlife and fish.
Obama just last year made a similar move to protect the nation’s waters, expanding the Pacific Remote Islands Marine National Monument to nearly 500,000 square miles, making it the largest marine reserve in the world.
Monday's conference in Valparaiso brings together nations to help combat ocean pollution caused by discarded plastics and the increasing levels of ocean acidification, which has damaged coral reefs and shellfish populations. This is a major problem for the US, which imports 90 percent of its seafood, and for Chile, with a coastline of almost 2,500 miles that’s critical to the economy.
The Obama administration is also expected to tackle overfishing, promising to launch a global initiative called "Sea Scout" to identify unregulated and unreported activity and to help prosecute illegal fishing organizations.
The US is part of a growing list of nations, including Britain, Gabon, Kiribati, New Zealand, and Palau, that have taken steps in recent months to protect sections of the sea.
This report contains material from the Associated Press.
[Editor's note: This story has been updated to clarify the overall area of newly protected waters.]