This article uses the Sargasso Sea as a case study to provide an analysis of the provisions of Part III of the Agreement under the United Nations Convention on the Law of the Sea on the Conservation and Sustainable Use of Marine Biological Diversity of Areas Beyond National Jurisdiction (BBNJ Agreement) on measures such as area-based management tools (ABMTs), including marine protected areas. The ability of the BBNJ Conference of the Parties (COP) to establish internationally legally binding ABMTs in areas beyond national jurisdiction (ABNJ) presents a new opportunity for the conservation of the Sargasso Sea. Existing work of the Sargasso Sea Commission, as well as the preparations it could make to support a proposal by one or more States Parties to the new COP for an ABMT in the Sargasso Sea are discussed, as is the comprehensive process the BBNJ Agreement establishes for stakeholder engagement as part of the submission of proposals. The Sargasso Sea Commission has a long history of collaboration with international organisations, governments, scientists and others to strengthen the stewardship of the Sargasso Sea. More recent activities to engage directly with the shipping industry stakeholder group specifically are discussed. Finally, the article discusses the work being undertaken in collecting the best available science, collaboration with other international frameworks and bodies and other stakeholders, and the preliminary work on the development of an outline management plan particularly in relation to ongoing monitoring using remote sensing capacity.

Age estimates from bomb 14C dating conflict with a well-recognized age reading protocol (grinding, polishing and staining in the sagittal plane) for otoliths of European eel (Anguilla anguilla). Proper alignment of calculated hatch years for 14C measurements taken from the earliest otolith growth—among the smallest otolith extractions to date for successful 14C analysis due to the advent of gas-AMS—was not achieved using age estimates from an accepted method. The realignment of otolith 14C values to a tropical bomb 14C reference chronology, which is most applicable to the Sargasso Sea as the natal origin of European eel, led to an increase of the original age estimates by 8 to 32 years. A maximum age of approximately 46 years was determined for the European eel specimen with the most massive otolith, of which mass is a reasonable proxy for age and was instrumental in identifying age estimate discrepancies. By extending the otolith mass-to-age relationships from this study to the most massive otoliths available from archived otoliths of Norway, an increase of up to several decades from the original otolith age estimates was discovered, leading to support for a potential lifespan of 70–100 years in the natural environment.