A Particularly Sensitive Sea Area (PSSA) is a comprehensive management tool available at the international level for reviewing attributes within an area vulnerable to damage by international shipping and for determining the most appropriate protective measures available through the IMO to address such vulnerability. A Particularly Sensitive Sea Area (PSSA) is an area of the marine environment that merits special protection through action by the IMO because of its significance for recognized ecological, socio-economic, or scientific attributes where such attributes may be vulnerable to damage by international shipping activities.

Although designation as a PSSA does not directly confer protection of a marine area, the process for designation includes identification of appropriate IMO protective measures in the area.  These associated protective measures (APMs) can already be in place or be put in place at the time of PSSA recognition. Additionally, the inclusion of PSSAs on international nautical charts highlights the area as an area deserving additional protection and generally promotes stewardship within the maritime community. To date, the IMO has designated 17 PSSAs offsite link worldwide, including two within the US.

In 2005, the IMO Assembly adopted the Revised Guidelines for the Identification and Designation of PSSAs (Revised PSSA Guidelines offsite link) to provide guidance to IMO Member Governments in the development, drafting, and submission of PSSA proposals, and provide the IMO with the assessment criteria for such proposals. To be recognized as a PSSA, three elements must be present:

1. the area must have certain attributes (ecological, socio-economic, or scientific) identified in the Revised PSSA Guidelines;
2. it must be vulnerable to damage by international shipping; and
3. there must be measures that can be adopted by the IMO to protect the vulnerable area  from international shipping (i.e., associated protective measures – APMs).

   Example of particularly sensitive sea area demarcation in chartlet. In a navigation chartlet, this boundary will mark the outer boundary of the PSSA in order to alert vessels of the area’s importance (U.S. Chart No. 1, p.75).

Papahānaumokuākea: This area was designated as a PSSA in 2008 in order to protect marine resources of ecological or cultural significance from damage by ships while also protecting mariners’ safety. The Associated Protective Measures for this PSSA include:

• areas to be avoided (ATBAs) depicted on international nautical charts, directing ships away from coral reefs
• Ship reporting system

Florida Keys: A PSSA was established in the Florida Keys in 2002 to raise awareness of the importance of protecting the particularly sensitive marine environments there from oil spills and hazardous materials. The three Associated Protective Measures to prevent damage from international shipping activities to the coral reef ecosystem are:

• Inclusion of the already-existing four IMO ATBAs in the area
• Amendment to the northernmost ATBA
• Three mandatory no-anchoring areas

Further information: 

• IMO page on PSSAs offsite link
• IMO Assembly Resolution 982, Revised Guidelines for the Identification and Designation of Particularly Sensitive Sea Areas (Dec. 1, 2005).
• Guidance Document for Submission of PSSA Proposals to IMO offsite link, MEPC.1/Circ.510 (May 10, 2006) [hereinafter PSSA Proposal Guidance Document] (providing guidance to assist IMO Member Governments in meeting the requirements of the revised 2005 PSSA Guidelines, resolution A.982(24)).
• “List of Special Areas, Emission Control Areas and Particularly Sensitive Sea Areas” offsite link

 Last updated July 29, 2020