Protecting for or from?: Unique high-seas oceanographic features demonstrate contrasting protection priorities for the high seas

Nearly half the surface of the Earth consists of the high seas, the ocean 200 nautical miles beyond a nation’s coastline, with a recent 2023 UN international agreement (BBNJ Treaty) requiring renewed political efforts to protect this vast area. Unique to this agreement, when ratified, will be its ability to create marine protected areas on the high seas. With various organizations and institutions beginning the race to champion their chosen biodiversity hotspot, two unique high seas oceanographic features have emerged: the Costa Rica Thermal Dome and the Sargasso Sea. In these high seas case studies, we investigate the fishing intensity, the corporate actors benefitting from the fishing effort, and shipping traffic to understand the current anthropogenic stress in both regions. We find anthropogenic activity is deeply intertwined with the biogeochemistry in these contrasting oceanographic high seas features. The Sargasso Sea is a sub-tropical gyre and is thus highly oligotrophic, while the Costa Rica thermal dome is a seasonal upwelling that brings nutrient-rich water to the euphotic zone, attracting highly migratory species and the corporate actors that aim to extract them. Understanding that the greatest current impact from anthropogenic activity on the high seas is industrialized fishing, the high seas case studies analyzed here pose the question, should we protect marine life and high seas habitat from current activity (such as in the Costa Rica thermal dome), or areas with very little anthropogenic activity that have endemic species and intrinsic natural value (the Sargasso Sea)? With the implementation of the BBNJ treaty on the horizon and limited tools to keep pace with industrial corporations who work to overexploit the high seas, it will be essential to identify the values behind the models we create to identify and champion high seas areas’ and if they are protecting marine life from harm or not.