The document discusses marine protected areas (MPAs) in the United States as managed by NOAA. It notes that over 1,600 MPAs have been established, protecting around 41% of US marine waters. The national system of MPAs coordinates management of these areas across different jurisdictions. While MPAs limit some activities like fishing to protect resources, most allow multiple uses. MPAs are classified based on their focus, level of protection, and other characteristics to facilitate management and conservation planning. NOAA's National MPA Center works to develop and support the national system of MPAs through activities like maintaining an MPA inventory and enhancing stewardship.