Designating Particularly Sensitive Sea Areas in Areas Beyond National Jurisdiction

While the International Maritime Organization's (IMO) Particularly Sensitive Sea Area (PSSA) concept has been operational for over 30 years, no state has ever brought forward a proposal for a high seas PSSA. This is despite the fact that shipping demonstrably poses a threat to high seas biodiversity. The adoption, by the United Nations, of a new implementing agreement for the conservation and sustainable use of biodiversity in areas beyond national jurisdiction (BBNJ Agreement) opens a new chapter in the governance of the high seas, and creates, for the first time, a legal mechanism, agreed at the global level, for the establishment of area-based management tools (ABMTs). This new agreement strengthens the arguments for utilizing the PSSA regime in the high seas and, as a consequence, has implications for the IMO, and how its member states consider the potential application of PSSAs in areas beyond national jurisdiction (ABNJ). Drawing on recent discussions concerning the potential to designate two specific high seas areas as PSSAs, namely, the Sargasso Sea and the Costa Rica Thermal Dome, this article examines the practical issues to be addressed when applying the PSSA concept to the high seas and considers the opportunities for advancing PSSA proposals through enhanced cooperation between the IMO and the parties to the BBNJ Agreement.