Preventing plastics pervading an oceanic oasis: Building the case for the Costa Rica Thermal Dome to become a World Heritage site in ABNJ

World Heritage status for selected sites in Areas Beyond National Jurisdiction is under active consideration, and the Costa Rica Thermal Dome in the eastern tropical Pacific Ocean is a feasible candidate site. A scientific expedition to the area in April 2017 added to biological baseline data but also confirmed presence of microplastics in the water column. National and regional efforts are being made by Central American countries to strengthen mechanisms for integrated ocean management, educate coastal communities and give early consideration to potential future threats such as ocean fertilisation. This paper concludes that to achieve World Heritage status for this iconic site requires an entity to both propose the area and report on its status. Bringing into force the Antigua Convention, a Regional Seas Convention for the Eastern Tropical Pacific, would provide an appropriate platform for Central American governments to enact protective measures.