US Department of Commerce, National Oceanic and Atmospheric Administration

About Marine Protected Areas

  > About MPAs

photo of a person hiking and beach in the background

Chances are you've visited a marine protected area and don't know it. If you've gone fishing in central California, diving in the Florida Keys, camping in Acadia, swimming in Cape Cod, snorkeling in the Virgin Islands, birding in Weeks Bay, hiking along the Olympic Coast, or boating in Thunder Bay, you've probably been one of thousands of visitors to a marine protected area (MPA).
Click here to download a brochure on marine protected areas.

"Marine protected area" is a broad term that encompasses a variety of conservation and management methods in the United States. MPA Executive Order 13158 defines an MPA as: "...any area of the marine environment that has been reserved by federal, state, territorial, tribal, or local laws or regulations to provide lasting protection for part or all of the natural and cultural resources therein."

The Framework for the National System of MPAs further defines the following key terms in this definition: "area," "marine environment,""reserved," lasting," and "protection."

The National Marine Protected Areas Center has developed a Classification System that provides agencies and stakeholders with a straightforward means to describe MPAs in purely functional terms using five objective characteristics common to most MPAs: 1) conservation focus; 2) level of protection; 3) permanence of protection; 4) constancy of protection; and 5) ecological scale of protection.

Marine Reserves vs. MPAs
A marine reserve is a highly protected type of MPA where removing or destroying natural or cultural resources is prohibited. These two terms are sometimes mistakenly used interchangeably. Marine reserves are rare in the United States, with about 3 percent of U.S. waters in these no-take areas. Reserves protect whole ecosystems, allowing them to return toward a more natural and balanced state. When a reserve is established, declining species can begin to recover. Biomass increases in the reserve, as does the size and density of organisms and the richness or diversity of species. Because many organisms are mobile, the benefits of the protection can be region-wide through an increased supply of larvae and juveniles moving out of the reserve. Similarly, highly mobile adult animals can be caught when they move outside the reserve, improving commercial and recreational fishing. Reserves can be an effective way to preserve biodiversity by protecting communities and providing refuge for rare organisms.
For more information, download the Marine Reserves in the United States fact sheet.

Get Involved
Find more information about things you can do to help our oceans and marine protected areas.


Framework for the National System of MPAs
MPA Programs
About the MPA Center
U.S. Classification System
Fact Sheets

For More Information
Write to