The International Convention on the Prevention of Pollution from Ships (MARPOL) provides for the designation of specific areas of the ocean as "special areas." Although MARPOL has six annexes that address marine pollution from the discharge or emission of harmful substances, special area designation is only available under annex I (oil), annex II (noxious liquid substances in bulk), and annex V (garbage). A special area is defined as "a sea area where for recognized technical reasons in relation to its oceanographical and ecological conditions and to the particular character of its traffic, the adoption of special mandatory methods for the prevention of sea pollution by oil, noxious liquid substances, or garbage, as applicable, is required." IMO Assembly Resolution A.927(22), Guidelines for the Designation of Special Areas under MARPOL 73/78. To obtain special area designation, a proposing government must show that basic MARPOL requirements do not provide adequate protection for the identified area. Additionally, a designation does not enter into force unless there are adequate reception facilities available in the area that can receive the particular harmful substance from affected ships.

Additional reference information: 

• IMO Assembly Resolution 982, Revised Guidelines for the Identification and Designation of Particularly Sensitive Sea Areas under MARPOL 73/78 (Dec. 1, 2005).
• IMO Assembly Resolution A.927(22), Guidelines for the Designation of Special Areas under MARPOL 73/78 and Guidelines for the Identification and Designation of Particularly Sensitive Sea Areas (Nov. 29, 2001). Also available for download.
• National System MPA Definitions and Criteria
• Marine Protected Areas of the United States