What’s the difference? National Marine Sanctuaries vs. Marine National Monuments

We wouldn’t blame you if you thought national marine sanctuaries and marine national monuments are the same thing. Both are categories of Marine Protected Areas (MPAs) – policy and conservation tools used to protect places in oceans, estuaries, and bodies of water like the Great Lakes – and while they have many similarities, they aren’t exactly alike.

We can think of MPAs as a toolbox that contains different tools that aim to solve specific problems in the world’s ocean. For example, a no-take MPA where fishing and other human activity is entirely prohibited might work well to protect endangered fishery stocks in the ocean, but the same strategy of protection wouldn’t be useful in an estuarine reserve or wetland environment. Some MPAs are seasonal while others are year-round. Some aim to protect entire ecosystems while others focus on individual or a small group of resources like wildlife, habitat, or cultural artifacts. Some are off limits while others allow recreation and tourism within their boundaries. In the United States, we have a diversified network of more than 1,000 MPAs, 16 of which (14 national marine sanctuaries and two marine national monuments) make up the National Marine Sanctuary System.

The main differences between sanctuaries and monuments in the U.S. is how we designate them and under which laws. Both protect rich cultural and historical resources, iconic species, and vibrant ecosystems but they do have different purposes, key elements, and applications in doing so. Check out our simplified list of what makes each unique. 

The wreck of the City of Washington in Florida Keys National Marine Sanctuary. Photo: David J. Ruck/NOAA

National Marine Sanctuaries

  • Designated by the National Oceanic and Atmospheric Administration (NOAA) or Congress under the National Marine Sanctuaries Act of 1972. NOAA holds sanctuaries in trust for the American people and NOAA’s Office of National Marine Sanctuaries (ONMS) administers the management of each area in the National Marine Sanctuary System.

  • The National Marine Sanctuaries Act is the only federal law written specifically for oceanic protection. This law grants NOAA the authority to develop management plans, issue regulations, and enforce those regulations for each sanctuary and the System as a whole.

  • The sanctuary designation process involves public engagement, including local community outreach, stakeholder involvement, and citizen participation before and after a sanctuary is designated.

  • There are two ways a new sanctuary can achieve designation:

    • Through a nomination process administered by ONMS. This includes accepting nominations for potential new sanctuaries from local communities. ONMS reviews nominations for diverse and broad support among other criteria. If they choose to accept a nomination, ONMS adds the site to its inventory of sites for future consideration. If NOAA decides to move forward, they will consult Congress and other federal, state, territorial, and local institutions and the public. The sanctuary designation is a long process with opportunities for community engagement built in as part of the National Marine Sanctuaries Act, and no site is officially designated without the final review and approval of the relevant governor(s) and Congress.

    • By Congress, Members of a community can encourage their Members of Congress in either the House of Representatives or the Senate to pass legislation to create a national marine sanctuary that is later signed into law by the President. Over the last 50 years, Congress has designated three national marine sanctuaries this way: Florida Keys, Hawaiian Islands Humpback Whale, and Stellwagen Bank

  •  Sanctuaries often take longer to designate than monuments. It may take several years to carry out the process for a single site.

  • All national marine sanctuaries require a community Advisory Council comprised of local stakeholders representing citizen, expert, and industry perspectives. These site-focused, community-based groups provide guidance and make recommendations to their sanctuary superintendent on issues including management, science, service, and stewardship.

Papahānaumokuākea Marine National Monument Photo: Robert Schwemmer

Marine National Monuments

  • Designated by the U.S. President through a presidential proclamation. The Antiquities Act of 1906 grants the president the authority to establish monuments that protect and preserve natural, or cultural landmarks of scientific or historic significance.

  • Monuments are usually managed by a group of federal and state agencies. In the case of marine national monuments, this includes NOAA, the U.S. Fish and Wildlife Service, and others. Each governance group is unique and depends on the language of the presidential proclamation that created the site.

  • The Antiquities Act does not require a participatory process. However, public engagement has resulted in the creation of monuments on land and in the ocean, including Papahānaumokuākea Marine National Monument, which President Barack Obama designated in 2016.

  • Monuments can be designated fairly quickly depending on how a president chooses to develop and sign their proclamation.

  • The National Marine Sanctuary System includes two marine national monuments as a result of ONMS being designated a management partner in each presidential proclamation. These sites are Papahānaumokuākea Marine National Monument in the northwestern Hawaiian islands (designated by President Barack Obama) and Rose Atoll Marine National Monument in American Samoa.

Click here to learn more about sanctuaries and monuments within the National Marine Sanctuary System, including a handy guide created by NOAA’s Office of National Marine Sanctuaries.