Navigating the BBNJ Treaty: Some Experiences from the Sargasso Sea

Abstract

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.

1. Introduction

Now that the immediate excitement surrounding the adoption of the Agreement under the United Nations (UN) Convention on the Law of the Sea (UNCLOS) on the Conservation and Sustainable Use of Marine Biological Diversity of Areas Beyond National Jurisdiction (BBNJ Agreement) has died down and the process of gathering 60 ratifications has been achieved with the treaty set to enter into force on 17 January 2026, ¹ there is an opportunity to make a more serious and detailed appraisal of the new regime—particularly of its innovative procedures and mechanisms.

The greatest achievement of the BBNJ Agreement is without doubt the power it gives to the Conference of the Parties (COP) to provide international recognition of area-based conservation measures, such as marine protected areas (MPAs), on the high seas. ² Under general international law, areas beyond national jurisdiction are res communis and not subject to appropriation by any State. ³ The freedom of navigation on the high seas prevents restrictions being imposed upon the vessels of a State without that State’s specific approval. ⁴ Consequently, restrictive measures adopted for high seas marine protected areas under existing treaty regimes are only binding on the parties to those treaties. Notable examples include the Convention for the Conservation of Antarctic Marine Living Resources ⁵ and the Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR Convention), ⁶ as well as restrictions imposed by the International Maritime Organization (IMO) under the International Convention for the Prevention of Pollution from Ships. ⁷ The powers established under the BBNJ Agreement are truly revolutionary and, if used effectively, they will assist the international community in achieving the ‘conservation and effective management’ of the 30 per cent of marine areas as per the targets set under the Kunming-Montreal Global Biodiversity Framework, adopted during the fifteenth meeting of the COP of the Convention on Biological Diversity, which support the achievement of the UN Sustainable Development Goals through the adoption of a series of targets. ⁸

The BBNJ Agreement also contains a number of interesting innovations in international law—not just in the law of the sea or biodiversity conservation. When the BBNJ Agreement comes into force, its COP will have the power to make legally binding decisions, ⁹ and by a qualified majority vote. ¹⁰ This power of a COP to make legally binding decisions is, as Whormsley argues, possibly unique. ¹¹ States Parties seeking to object to decisions may do so, ¹² but only on specific grounds which they must justify on an ongoing basis, again an innovative arrangement for a multilateral agreement. ¹³ Funding for the BBNJ bodies comes not just from a normal UN annual levy but from an innovative charge of an extra 50 per cent on assessed contributions of developed States Parties. ¹⁴ This is intended to provide core funding until the COP has decided on the ‘modalities for the sharing of monetary benefits from marine genetic resource activities’. ¹⁵ Another interesting first is the power given to the BBNJ COP to make requests for Advisory Opinions from the International Tribunal for the Law of the Sea (ITLOS) on specific issues—the first such provision in a global treaty. ¹⁶

However, the main focus of this article is the general regime for the designation of area-based management tools (ABMTs), including MPAs, in Part III BBNJ Agreement and, more specifically, the avenues open to States Parties to make proposals for the recognition of such ABMTs on the high seas. This has particular significance for the conservation of the Sargasso Sea, which is, as explained in Section 2, a unique open ocean ecosystem on the high seas. ¹⁷

Section 2 will provide details about the origins and work of the Sargasso Sea Commission (SSC), which in many ways already reflects some of the ambitions of the BBNJ Agreement in that it is mandated to use ‘best available science’, promote the precautionary and ecosystem approaches ¹⁸ as well the ‘stewardship’ ¹⁹ of the Sargasso Sea and to work through existing regional and international organisations to conserve the ecosystem ‘for the benefit of present and future generations’. ²⁰ Section 3 will examine in more detail the provisions of Part III BBNJ Agreement and the procedures for proposing and establishing ABMTs. Section 4 will look at the work that the SSC is doing in preparation for the entry into force of the BBNJ Agreement to ensure that it will be in a good position to support a proposal by one or more States Parties to the new COP for an ABMT in the high seas area of the Sargasso Sea.

2. Background of the Sargasso Sea Project: aspirations and achievements

The Sargasso Sea is an ideal case study for high seas protection efforts because it is a highly studied ecosystem, a haven for the biodiversity of a number of threatened and endangered species and a classic lacuna in the existing high seas governance regime. ²¹

Home to specially adapted species found nowhere else on earth, the Sargasso Sea is a dynamic open ocean ecosystem around the islands of Bermuda that does not have any land boundaries. Its borders are determined by oceanographic features, including the circulating currents of the North Atlantic subtropical gyre. The basis of the ecosystem is two species of the golden Sargassum seaweed (S natans and S fluitans), a holopelagic algae (i.e. that never attaches to the seabed at any stage in its lifecycle) that floats on the surface using grape-shaped float bladders that grow along its fronds and reproduces by fragmentation. Sargassum supports several endemic species designed to spend their entire lives in the algae. It also acts as an invaluable developmental habitat for many species of commercially exploited pelagic fish, including blue and white marlin, tunas, dolphinfish, jacks and tripletails, to the extent that, it has been designated as ‘essential fish habitat’ in the United States (US) by the National Oceanic and Atmospheric Administration. ²² All species of Atlantic Sea turtles use Sargassum as a nursery habitat, foraging ground and shelter from predators. Furthermore, the Sargasso Sea is the only known spawning area for the endangered American eel (Anguilla rostrata) and critically endangered European eel (A anguilla). ²³ These highly migratory catadromous ²⁴ fish spawn in the Sargasso Sea but spend most of their lives in fresh and brackish water systems in the wide-ranging rivers and estuaries connected to the Atlantic basin. The only UNCLOS provision dealing with such species is Article 67, but it does not provide any specific mechanisms for the conservation of breeding or nursery habitats for such species in the high seas. ABMT mechanisms under the BBNJ Agreement would allow holistic conservation measures to be established for ABNJ for the first time. The advantages of these ABMTs include preserving essential developmental and migratory habitats, reducing the impacts of cumulative pressures on ecosystems, and acting to protect areas from threats posed by new activities, such as for example sediment plumes from seabed mining activities.

The Sargasso Sea is also a migratory pathway for many species of sharks and rays, including the endangered Porbeagle shark that is thought to pup in the Sargasso Sea, as well as many species of cetaceans, including North Atlantic humpback whales, sperm whales and Cuvier’s beaked whales. ²⁵ The Sargasso Sea area also contains a number of seamounts, underwater mountains that drive nutrients to the surface creating havens for biodiversity, including those near the Bermuda platform and the New England and the Corner Rise Seamounts chains.

For an ecosystem with such unique ecological and economic importance, it is remarkable that there is no regional organisation with general fisheries competence nor one with an environmental mandate. The global regimes of the International Seabed Authority (ISA), for seabed minerals in the Area (that is, the seabed and ocean floor beyond national jurisdiction that constitutes the common heritage of mankind), and the IMO, for regulation of international shipping, apply to the entire Sargasso Sea, as does the competence of the International Convention for the Conservation of Atlantic Tunas (ICCAT), but only in respect of ‘tuna and tuna-like species’. ²⁶ The North-West Atlantic Fisheries Organization (NAFO) which regulates non-tuna species applies only to a small sliver of the northern Sargasso Sea. ²⁷ As Freestone and Gjerde put it, ‘despite the plethora of international organisations with an interest in ABNJ, there are only a handful with actual management competence in the Sargasso Sea area and none with a core focus on comprehensive conservation of marine biodiversity or ecosystems’. ²⁸

The combination of the striking natural imagery ²⁹ of the Sargasso Sea, its ecological value and its vulnerability to exploitation due to its status as a lacuna in the legal regime for the high seas, has increased international interest in its conservation. In 2011, the Sargasso Sea Alliance (SSA), which had been set up in 2010 and championed by the Government of Bermuda, produced a comprehensive baseline science case of the Sargasso Sea ecosystem and the human pressures. ³⁰ This report was the basis of a decision of the Convention on Biological Diversity (CBD) Subsidiary Body on Scientific, Technical and Technological Advice (SBSTTA), acting on a proposal by the Bermudian Government in 2011 that a defined area of the Sargasso Sea be described as an ecologically or biologically-significant area (EBSA) under the CBD. ³¹ That proposal was approved by the States Parties to the CBD in 2012. ³² The EBSA description carries with it no management authority but, as Roe et al observed, it was hoped that this ‘would mean that other sectoral organizations would take seriously proposals for the Sargasso Sea’s conservation or protection’. ³³ Subsequently, the Corner Rise Seamounts, which overlap with the Sargasso Sea EBSA, were added to the list of EBSAs at CBD COP12 in 2014. ³⁴

After a series of preparatory negotiations, ³⁵ the Government of Bermuda in collaboration with the SSA convened an historic meeting in Bermuda in 2014 to adopt the Hamilton Declaration on Collaboration for the Conservation of the Sargasso Sea (Hamilton Declaration). ³⁶ This non-legally binding, voluntary declaration aimed to ‘encourage and facilitate voluntary collaboration toward the conservation of the Sargasso Sea’. ³⁷ The Hamilton Declaration has ten government signatories—six of whom are sovereign States. ³⁸ The government signatories to the Hamilton Declaration agreed to the establishment by the Government of Bermuda of the SSC to, inter alia, ‘exercise a stewardship role for the Sargasso Sea and keep its health, productivity and resilience under continual review’ and ‘develop a work programme and action plans for the conservation of the Sargasso Sea ecosystem’. ³⁹ Significantly, the Hamilton Declaration established a formal Sargasso Sea Geographical Area of Collaboration (GAC) that excluded the exclusive economic zones (EEZs) of adjacent States, so that it constitutes solely a high seas area. ⁴⁰

The SSC, ⁴¹ with a small Secretariat, built upon the work of the SSA and has been operational for more than a decade. ⁴² It has sought to advance its aims through existing legal regimes, which includes establishing memoranda of understanding (MOUs) with the ISA (2020), NAFO (2023), ICCAT (2024), the Inter-American Sea Turtle Convention (2022) and OSPAR (2024). ⁴³ The SSC has observer status at the ISA and attends regular meetings of ICCAT as part of the United Kingdom (UK)/Bermuda delegation. It has its own chapter—the only named ecosystem to be so included—in each of the three UN World Ocean Assessments. ⁴⁴ In 2014, the SSC provided scientific support to Monaco ⁴⁵ when it proposed the listing of the European eel in Appendix II of the Convention on the Conservation of Migratory Species of Wild Animals (CMS), on the basis that inter alia it had ‘a conservation status which would significantly benefit from the international co-operation’. ⁴⁶ Subsequently, with the support of the Governments of Sweden and Monaco, the SSC sponsored and co-organised with the CMS Secretariat three meetings of the European Eel Range States. ⁴⁷ This fed into CMS COP13 mandating the development of a Single Species Action Plan for the European eel in 2020. ⁴⁸ In 2023, the SSC also co-hosted a workshop with the IMO and other bodies on Particularly Sensitive Sea Areas (PSSAs) on the high seas to explore the feasibility of pursuing a PSSA as a conservation measure in the high seas areas of the Sargasso Sea and the Eastern Tropical Pacific Thermal Dome. ⁴⁹ In 2024, the SSC supported a workshop on Important Marine Mammal Areas (IMMA) in the Caribbean and North Atlantic. That workshop proposed the identification of an IMMA for the humpback whale migratory corridor that stretches from the Antilles to the Barents Sea. ⁵⁰ Like an EBSA description, this designation has no legal status but can provide important justification for conservation measures.

The only legally binding conservation measure to date that can be directly attributed to the work of the Sargasso Sea Project has been the complete closure of some seamounts to bottom trawling in the Sargasso Sea GAC by NAFO as a result of a request by the US and the European Union (EU). ⁵¹ In 2007, NAFO had closed four seamount chains to bottom fishing activities, including Orphan Knoll, Corner Rise, Newfoundland and New England Seamounts. ⁵² However, it remained legal to conduct such fisheries in the ‘closed’ seamounts, as long as exploratory fishery protocols and impact assessments had been submitted to, and approved by, the Scientific Council and the Fisheries Commission. ⁵³ After some internal disagreements, ⁵⁴ at the thirty-seventh NAFO Annual Meeting in Halifax, NAFO agreed to prohibit the use of attachments of mid-water trawling gear that could damage or touch the seabed and required all vulnerable marine ecosystem indicator species caught during mid-water trawling to be reported. It also completely closed all seamounts in the NAFO area to bottom trawling activities until the end of 2020 by prohibiting bottom trawling exemptions for exploratory fishing. ⁵⁵ In September 2021, the NAFO Commission agreed to continue that protection of seamounts until 2026. ⁵⁶

The Sargasso Sea Project has succeeded in bringing international attention to an iconic high seas ecosystem and, through its attempts to use the EBSA designation, has demonstrated the need for a more holistic approach to high seas governance. ⁵⁷ The BBNJ Agreement and the tools it provides to establish ABMTs now present this as a real possibility.

3. Opportunities for area-based management under the BBNJ Agreement

Although Bodansky describes the BBNJ Agreement as ‘four treaties in one’, ⁵⁸ the overarching framework, including general principles, the Scientific and Technical Body (STB), the innovative financing mechanisms, the Clearing-House Mechanism and the dispute resolution provisions, do pull the regime together. ⁵⁹ It is nevertheless true to say that the main provisions of interest to the Sargasso Sea are Part III BBNJ Agreement on ABMTs, including MPAs ⁶⁰ and, to a lesser extent, Part IV on Environmental Impact Assessments. ⁶¹ However, to operationalise these provisions it is important also to bear in mind the general principles and approaches set out in Article 7 BBNJ Agreement and the requirements of Article 5 concerning its relationship to other international frameworks and bodies (IFBs). In making any decision, particularly in relation to an ABMT/MPA proposal, the COP must consider the overarching requirement of Article 5(2):

This Agreement shall be interpreted and applied in a manner that does not undermine relevant legal instruments and frameworks and relevant global, regional, subregional and sectoral bodies and that promotes coherence and coordination with those instruments, frameworks and bodies. ⁶²

The concept of ‘not undermining’ emerged early in the negotiations, insisted upon by States that were keen to protect the autonomy of existing organisations—particularly fishery management bodies. ⁶³ In the final text, the phrase is balanced by the parallel obligation of promoting ‘coherence and coordination’ with other instruments and bodies. ⁶⁴ These obligations are imposed directly on the States Parties to the BBNJ Agreement—who must also ‘endeavour to promote, as appropriate, the objectives of this Agreement when participating in decision-making under other [IFBs]’. ⁶⁵ How the States Parties meeting as the COP will approach these issues is yet to be seen. ⁶⁶ It seems likely they will initially be extremely cautious, but Section 4 suggests some important issues that will need to be taken into account.

Part III represents one of the most significant and eagerly awaited successes of the negotiations. Article 17(a) declares that the first objective is ‘the establishment of a comprehensive system of area-based management tools, with ecologically representative and well-connected networks of marine protected areas’. ⁶⁷ Part III establishes for the first time a procedure for the international recognition of such management measures on the high seas. Such areas have been established at a regional or sectoral level. ⁶⁸ However, measures approved by the BBNJ Agreement COP under Part III will attract global recognition—or, at least, recognition from all the States Parties to the BBNJ Agreement. If the BBNJ Agreement attracts wide participation, then some of its provisions, particularly the principles and the concept of international recognition of high seas ABMTs, may well pass into customary law in much the same way as have some concepts, principles and even detailed provisions of UNCLOS. ⁶⁹

The BBNJ Agreement imposes rigorous requirements for establishing ABMT/MPAs. First, proposals to use the tools offered by Part III for a particular defined area may only be made in writing to the Secretariat by a State Party or States Parties. ⁷⁰ Such proposals must be preceded by extensive ‘collaboration and consultation’ as appropriate ‘with relevant stakeholders, including States and global, regional, subregional and sectoral bodies, as well as civil society, the scientific community, the private sector, Indigenous Peoples and local communities’. ⁷¹ In addition, proposals shall be ‘formulated on the basis of the best available science and scientific information and, where available, relevant traditional knowledge of Indigenous Peoples and local communities, taking into account the precautionary approach and an ecosystem approach’. ⁷²

The substantive content of any such proposal is detailed in Article 19, which requires, inter alia: (a) a geographic/spatial description which must be based on one or more of the indicative criteria for identification of areas adumbrated in Annex 1; ⁷³ (b) threats/vulnerabilities and values; (c) ecological factors; (d) scientific data concerning the standards and criteria for the identification of the area; (e) the role of relevant global, regional and sectoral bodies; (f) human activities in the area; (g) conservation and sustainable use objectives; (h) existing measures in the area or areas adjacent; and (i) a draft management plan. Once the Secretariat has received a proposal, it makes it publicly available and sends it to the STB for a ‘preliminary review’ to ensure that it contains the requisite information. ⁷⁴ The outcome of that review is then sent to the proponent(s), who have the opportunity to resubmit the application—taking into account the STB’s comments.

At this point the Secretariat initiates its own extensive consultation process under Article 21. Despite the extensive preliminary consultation requirements under Article 19(2), Article 21 requires the Secretariat to circulate the proposal to a number of groups of possible stakeholders to ‘gather input’ from them on a series of specific issues. There are three groups of stakeholders, each with views to be sought on slightly different issues: (a) States, in particular adjacent coastal States; ⁷⁵ (b) bodies of relevant legal instruments and frameworks and relevant global, regional, subregional and sectoral bodies; ⁷⁶ and (c) Indigenous Peoples and local communities with relevant traditional knowledge, the scientific community, civil society and other relevant stakeholders. ⁷⁷ In addition, more rigorous consultation is required of States whose EEZs completely surround a high seas area if a measure is being proposed there. ⁷⁸ Once these Secretariat-initiated consultations are completed, the proponent may revise the proposal as appropriate or ‘respond to substantive contributions not reflected in the proposal’. The revised proposal then goes back again to the STB which makes a recommendation to the COP.

This is not a simple process and, although Article 20(6) requires the process to be ‘time-bound’, it will clearly require a considerable amount of time and effort. It is possible that the time scales involved might act as a possible deterrent. On the other hand, the prize of global recognition is clearly a major incentive and the rigour of the procedure seems likely to give these decisions even greater credibility.

Once the final proposal is received by the COP, the COP has a number of options open to it, provided that it respects the competences of, and does not undermine, relevant IFBs. ⁷⁹ It can take a decision to adopt an ABMT/MPA. ⁸⁰ As discussed in Section 1, the significance of this power cannot be understated. It is very rare, arguably unique, for a COP to be given the power to make legally binding decisions of this kind. ⁸¹ The COP may also make a decision to adopt measures compatible with those made by another competent IFB ‘in cooperation and coordination’ with them. ⁸² Alternatively, if the COP finds that the measures proposed to it are already within the competence of other IFBs, then it can make recommendations to the States Parties to the BBNJ Agreement and to those IFBs ‘to promote the adoption of relevant measures’. ⁸³

Article 22(4) addresses the situation where another IFB has established an ABMT. Negotiators wanted to ensure that such ABMTs were not automatically recognised by the COP because they may have been established using different (perhaps less rigorous) criteria than required under the BBNJ Agreement. Thus, Article 22(4) allows the COP in plenary to ‘consider and … decide, as appropriate, to develop a mechanism regarding existing area-based management tools, including marine protected areas’. ⁸⁴

4. Attempting to navigate the BBNJ Agreement: the Sargasso Sea experience

In the course of more than a decade of work and, in particular, during the last two years of intensive efforts with the Global Environment Facility (GEF) Stewardship Project and its co-financing from the Fund français pour l’environnement mondial (FFEM), ⁸⁵ the Sargasso Sea team has gained a wealth of experience in approaching some of the challenges of developing area-based and species-based tools within a variety of regimes. ⁸⁶ This section will look at four areas where the Sargasso Sea experience might be able to offer some insights into the ways in which some of the more challenging obligations of Part III of the BBNJ Agreement can be addressed.

It will look at the Sargasso Sea Stewardship Project’s work in four areas: collaboration with IFBs; consultation requirements; the preparation of the baseline case using ‘best available science’; and the preliminary work on the development of an outline management plan—particularly in relation to ongoing monitoring using remote sensing capacity.

4.1. Collaboration with other international frameworks and bodies

The BBNJ Agreement crystallises the general customary law principle of cooperation upon which effective governance of common spaces must be based. ⁸⁷ It is given added practical significance in the BBNJ processes because extensive consultation is a threshold requirement for the initial making of a proposal, and because ‘relevant legal instruments and frameworks and relevant global, regional, subregional and sectoral bodies’ will be approached by the Secretariat for their comments. ⁸⁸

It is now at least arguable that States Parties to the BBNJ Agreement are obliged to consult with the SSC—or at least with the States signatory to the Hamilton Declaration. ⁸⁹ The SSC is mandated to facilitate collaboration ‘to the extent possible, in pursuing conservation measures for the Sargasso Sea ecosystem through existing regional and international organisations with relevant competences’. ⁹⁰ At an early stage, the Sargasso Sea Stewardship Project had to identify the wide number and variety of IFBs that have formal competence or interest in that high seas area. ⁹¹ To this end, the SSC has signed general MOUs with most of the bodies that have such competences. There are currently five such MOUs in force. ⁹² They are mutually supportive—an approach which has been praised as truly collaborative. ⁹³ There is clearly no blueprint for such collaboration, but the obvious starting point is a detailed assessment of the competences of such bodies and an assessment of the extent to which they have already taken action themselves in relation to high seas concerns. ⁹⁴

Furthermore, where appropriate, the SSC has drawn upon the organisational expertise of its signatory governments who are also members of those organisations. ⁹⁵ It was, for example, the Government of Bermuda that, drawing on the work of the Sargasso Sea science team in its 2011 baseline report, ⁹⁶ made the proposal for the Sargasso Sea to be described as an EBSA. ⁹⁷ Also, it was the US and the EU that in 2012 requested the NAFO Fisheries Commission to investigate whether, in the light of the 2011 Sargasso Sea EBSA description, there was a ‘need for any management measures including closure to protect this ecosystem’. ⁹⁸ Similarly, the Government of Monaco was willing to take forward a proposal, prepared with the scientific expertise provided by the SSC, to list the European eel under Appendix II CMS in November 2014. ⁹⁹ In its work with ICCAT, the Sargasso Sea team was initially able to sit as part of the Bermuda delegation, while the UK was a Member State of the EU. ¹⁰⁰ The team has been active in the work of the Subcommittee on Ecosystem and Bycatch (SCEco) for more than a decade—contributing a significant amount to their work. ¹⁰¹ Since Brexit in January 2020, Bermuda now sits as a member of the (much larger) UK delegation. ¹⁰²

Once the BBNJ Agreement comes into force, the Hamilton Declaration signatory governments that are party to it will play an essential role in putting forward any proposal for an ABMT in respect of the Sargasso Sea.

4.2. Stakeholder consultation

The BBNJ Agreement reflects a trend in international law of including non-State actors in the legal process; this is particularly exemplified by its provisions on stakeholder consultation. While States are the traditional lawmakers, an increasingly wide range of actors are now involved in international environmental law, including industry, academia, civil society and Indigenous Peoples. Involving a wide range of stakeholders not only makes environmental law and conservation measures more equitable; it also increases the chance they will work better in the long run because of ‘buy in’ from the players specifically affected. The BBNJ Agreement is one of the few international legal instruments that explicitly creates ‘direct participatory rights’ for non-State actors in its text. ¹⁰³ The specific stakeholder groups mentioned in Article 19(2) are ‘States and global, regional, subregional and sectoral bodies, as well as civil society, the scientific community, the private sector, Indigenous Peoples and local communities’. ¹⁰⁴

A two-part stakeholder consultation process is created by Article 19(3) that obliges parties to consult with relevant stakeholders in the formulation of proposals for ABMTs under Part III, and Article 21 which requires a second round of consultations with relevant stakeholders after the proposal has been submitted and preliminarily reviewed by the SBT. It seems clear from this language that it reflects a hierarchy, with States and international organisations carrying the most weight, followed by the other non-State actors. Interestingly, while all groups should be consulted in the initial formulation stage of a proposal, ‘the private sector’ is not specifically mentioned in the second, public phase of consultations. Presumably, however, private sector actors are included in ‘other relevant stakeholders’ under Article 21(2)(c) and their interests may also be represented by States and within international organisations.

The SSC, having been created by a political declaration rather than a treaty, is a non-State actor. As it does not have international legal personality, there is a question as to whether it qualifies as a relevant ‘body’ for the purposes of the definition of IFBs in Article 19, although it is certainly entitled to be the subject of consultation and collaboration under Article 19(2). The SSC brings together governmental representatives and scientific experts. It provides scientific and legal expertise in order to amplify global awareness of the important Sargasso Sea ecosystem. Layered within the Hamilton Declaration are other non-State actors as the Hamilton Declaration specifically permits governments to be signatories. These include Bermuda, an extremely important champion, as the only land mass within the Sargasso Sea, and the Azores, an archipelago in the North Atlantic Eastern Basin with high connectivity to the Sargasso Sea.

In addition to the collaboration with a wide range of international, regional and sectoral bodies discussed in Section 3, ¹⁰⁵ the SSC also liaises with the secondary groups of stakeholders represented in the BBNJ Agreement. The scientific community is a very important stakeholder for the SSC because of the organisation’s commitment to scientific accuracy and transparency. The SSC has also supported proposals to sectoral organisations that have an impact on governance and conservation measures that must be based on sound scientific inputs from the academic community. ¹⁰⁶ It has historically engaged less with Indigenous Peoples and local communities. There are no known Indigenous Peoples that use the Sargasso Sea—it is too far away from land to make artisanal access practical. ¹⁰⁷ However, there is significant indigenous involvement, especially in Canada, in anguillid eels that originate in the Sargasso Sea. Given the lead initiative of the Government of Bermuda since 2010, and the ecological connectivity of the Sargasso Sea to Bermudan waters, the local population of Bermuda is also a significant stakeholder.

As discussed earlier in this section, Article 19 BBNJ Agreement makes it clear that any proposal for consideration by the BBNJ COP needs to have involved extensive consultations. In order to ensure the consultation process would be useful in project implementation, that task was deliberately devolved to a third party entity to ensure that there would be meaningful and objective engagement of stakeholders throughout the project process. ¹⁰⁸ Their mandate was to develop a strategy for approval by the SSC and then assist with implementing it. The agreed strategy divided stakeholders into three categories:

‘Guardians’: principally focused on the conservation of the Sargasso Sea, either directly or indirectly.

‘Users’: who realise direct or indirect commercial gain from legal exploitation of the natural resources within, or that pass through, the Sargasso Sea.

‘Beneficiaries’: all others globally, who derive benefit from the Sargasso Sea, whether consequent of its guardianship or commercial use, but are neither active ‘Guardians’ nor ‘Users’. ¹⁰⁹

This categorisation ensures that project stakeholder engagement can be tailored to a group’s particular interests. The strategy aims to increase cooperation between guardians and other groups that may have commercial interests in the Sargasso Sea. ¹¹⁰

Four stakeholder engagement workshops have been held so far. The first brought together key project stakeholders, including signatory governments’ representatives and the Commissioners, as well as representatives from collaborating IFBs. ¹¹¹ Three more stakeholder workshops have been held with members of the shipping community that have established mechanisms for engagement of this kind. ¹¹² The main output has been the formation of a working group to discuss possible governance frameworks that address the vulnerabilities of the Sargasso Sea to international shipping. ¹¹³ A similar set of stakeholder engagement workshops for the fishing industry are in development, although engaging with the private sector stakeholder group related to fisheries is more challenging as there are no effective representative bodies for the fishing industry itself. Consequently, any engagement needs to be initially undertaken through the Regional Fisheries Management Organisations (RFMOs) and Regional Fisheries Advisory Bodies.

4.3. Preparation of the baseline case using the ‘best available science’

Proposals for ABMTs or MPAs will depend upon a scientific case for protective measures. The established GEF Large Marine Ecosystem (LME) methodology involves a Transboundary Diagnostic Analysis (TDA) that looks at the state of the ecosystem, existing threats and pressures and conducts a ‘causal chain analysis’ of key concerns. The Sargasso Sea Stewardship Project has amended that TDA model to a Socio-Ecosystem Diagnostic Analysis (SEDA). Nevertheless, the overall stepwise approach remains similar to that of a TDA. This methodology is transferable to other projects that are considering making proposals for ABMTs in other high seas ecosystems.

The main technical role of a SEDA is to define the current status of the ecosystem (the community of organisms and their physical environment), identify environmental threats or problems that threaten the long-term integrity and sustainability of the ecosystem and then to confirm and set priorities for action to address them.

The challenge of utilising the ‘best available science’ is a real issue. For the Sargasso Sea Stewardship Project, a number of leading scientific organisations were contracted to provide information on the key issues, such as oceanography, ¹¹⁴ marine ecosystems, ¹¹⁵ fisheries, ¹¹⁶ migratory species and human activities and impacts ¹¹⁷ as well as existing governance frameworks. The final drafts were then reviewed by a specialist SEDA review board and sent to key stakeholders for formal review and comment.

Ultimately, the SEDA provides the factual basis for the formulation of a Strategic Action Programme (SAP). However, the SEDA is also part of a larger, facilitative process of engagement and consultation with all the key stakeholders, right from the initial SEDA preparatory work through to the subsequent development of the possible solutions, and there may be alternative courses, during the formulation of the Strategic Action Programme. The SEDA is a mechanism to help the stakeholders to ‘agree on the facts’. Furthermore, the SEDA should be seen as more than just an analysis of data and information. It is a powerful process that can help create confidence and trust among the partners involved and thereby create strong partnerships and interactions. Importantly, the process is built on the experience from other LME management processes. ¹¹⁸

Once the SEDA document is completed and has been reviewed by the appropriate partners and stakeholders, the next step is to undertake an Ecosystem Valuation. This involves an overall socioeconomic valuation of the goods and services provided by the ecosystem. It will then focus on developing an estimation of the socioeconomic costs (to society) of the main threats to the Sargasso Sea. It will also aim to identify the main beneficiaries (national, regional and global) of these goods and services. The final output from this process will be a Cost Benefit Analysis (CBA) of various conservation and stewardship options. The CBA will aim to compare a ‘business-as-usual’ scenario with an improved conservation and management scenario, while taking into account not only the cost-benefits but the actual cost of adopting a more effective management approach.

Once completed, the SEDA, the Ecosystem Valuation and CBA should provide ample justification for developing appropriate conservation and management approaches, including proposals for ABMTs before the BBNJ Agreement COP.

4.4. Development of an outline management plan, particularly in relation to ongoing monitoring

One of the objectives of Part III BBNJ Agreement is to ‘[s]upport developing States Parties … in developing, implementing, monitoring, managing and enforcing area-based management tools, including marine protected areas’. ¹¹⁹ Article 19 further notes that any ABMT proposals must include a draft management plan encompassing the proposed measures and outlining proposed monitoring, research and review activities to achieve the specified objectives. The BBNJ Agreement also requires that such ABMTs undergo monitoring and periodical review by the STB.

As noted in Section 4.3, the main purpose of the SEDA is to provide a factual basis for the formulation of a SAP. Development and finalisation of the SEDA will also include an analysis of the existing governance arrangements and responsibilities for the area in question, although this may be presented as a standalone document to advise on the development of the SAP.

The SAP is essentially an agreed management approach for the area in question. The SAP sets out specific actions required by all the partners or players in order to address the impacts and threats to the ecosystem. It further outlines the policy, legal and institutional improvements and investments needed to resolve the priority ecosystem problems. The SAP is therefore a ‘negotiated’ agreement by appropriate stakeholders and partners with the aim of arriving at an adopted management plan focused on specific defined and agreed objectives. These established GEF Project processes link well the requirements of the BBNJ Agreement. The SAP will outline a management plan for consideration and input from all engaged stakeholders and partners.

It would obviously be prohibitively expensive and time-consuming, as well as probably unnecessary, to try to measure every physical, chemical and biological ocean-atmosphere parameter, let alone the social and economic status or the efficacy of policy and governance of an ocean ecosystem. Other LME projects have agreed on specific indicators of health and wellbeing within the ecosystem-based management approach ¹²⁰ so as to arrive at a set of Ecosystem Quality Objectives (EQOs) that need to be maintained to ensure the effective functioning of the overall ecosystem(s). Thus, the first requirement of any effective SAP is the need for a comprehensive system of ocean observation and monitoring of key indicators, including social and economic parameters.

One of the high priorities, therefore, during the adoption of the EQOs and the negotiation of the SAP must be the task of defining the ecosystem monitoring procedures and responsibilities. This is also identified as a requirement by Article 19(4)(f) BBNJ Agreement. This will inevitably be a ‘negotiated’ process. Effective ecosystem monitoring requires funding, personnel and equipment. The negotiation here will need to identify those partners that can provide such resources. Even where there may be good long-term records of various ecosystem conditions that can help to define the EQOs, the status of those EQOs and their defining parameters need to be reassessed regularly. Realtime monitoring at sea to detect and record changes in physical, chemical and biological parameters can be very expensive. Perhaps the most innovative and valuable in terms of cost reduction, along with ‘big data’ acquisition, is access to remote sensing through satellites which can capture a substantial area of sea surface (and deeper) data for monitoring of oceanographic parameters as well as monitoring of activities on the high seas that could be detrimental to the wellbeing of a ‘managed’ area. ¹²¹

Refining the relationship between data analysis and management, policy and overall governance strategies for high seas areas, has never been more critical and imperative than it is today, especially to meet the requirements of the BBNJ Agreement. ¹²² In the context of ABNJ, the amounts of data involved are truly enormous and the ability to process and manipulate these enormous amounts of data is still a work in progress. The development of artificial intelligence (AI) also promises to allow the handling and analysis of massive amounts of data, providing a vision of future high seas governance based on the BBNJ Agreement and the ways in which big data and AI can play a crucial role in meeting the exciting challenges that the new agreement poses. ¹²³

5. Conclusion

The Sargasso Sea Project began in 2010 with an explicit agenda to work with existing international organisations to put conservation measures in place for this iconic ecosystem. ¹²⁴ As this article has described in some detail, despite some successes with securing governments’ support, notably, with the CBD EBSA process, CMS and NAFO, it was clear early on that this was not an easy task. The finalisation of the BBNJ Agreement, particularly Part III, has therefore represented an important and perhaps overdue recalibration of the modalities available for the establishment of ABMTs on the high seas.

Despite the justified excitement about these new opportunities presented by the BBNJ Agreement, it is still not an easy task. The negotiators have established rigorous, indeed potentially onerous, requirements for all the proposals for ABMTs. The Preparatory Commission held its first substantive session in April 2025, ¹²⁵ a second from 18–29 August 2025 and will also have at least one more two-week session from 23 March–3 April 2026. On 17 September 2025, the BBNJ Agreement received sufficient ratifications to bring it into force on 17 January 2026. The COP must then hold its first session within one year. ¹²⁶ Given the large number of organisational decisions that the BBNJ Agreement itself has required of COP1, it may only have time to deal with the institutional issues which it is mandated to agree. How and when the COP will first be called on to interpret the procedural requirements for Part III remains to be seen. As the overwhelming majority of the States Parties participating in the COP will already be parties to the existing global and regional marine treaties, it seems likely that the COP will want to be seen to be collegial (as required by Article 5) and its decisions therefore will, at least initially, be cautious. ¹²⁷ It is important therefore that the first proposals it receives are carefully prepared. It is hoped that the experience gained in relation to the Sargasso Sea may assist with future proposals for ABMTs.