On 17 January 2026, we entered a new era for the preservation of biodiversity on the high seas as the Biodiversity Beyond National Jurisdiction (BBNJ) Agreement entered into force. Here, we explore how the Thermal Dome, a unique oceanographic feature located in the Eastern Tropical Pacific and a dynamic hot spot for biological diversity, can be used as a case study to illustrate how conservation aims could be achieved with minimum impact on shipping operations – leading the way for future debate and discussions on high seas protection and shipping.
Contents
The BBNJ Agreement – a new era for ocean conservation
The Thermal Dome, a climate-driven anomaly
The Thermal Dome is under threat
The Thermal Dome- the first high seas PSSA?
What else are we doing related to the BBNJ Agreement?
The BBNJ Agreement – a new era for ocean conservation
After nearly two decades of negotiations, the BBNJ Agreement entered into force on 17 January 2026. Covering two-thirds of the global ocean, this landmark treaty aims to conserve and sustainably use marine biodiversity in areas beyond national jurisdiction (ABNJ). It introduces measures such as area-based management tools (ABMTS) which include marine protected areas (MPAs) as well as incorporating environmental impact assessments (EIAs), and mechanisms for capacity-building and technology transfer, all under the framework of the UN Convention on the Law of the Sea (UNCLOS).
For the shipping industry, the implications could be significant. While international shipping is already regulated under stringent IMO conventions like MARPOL, the BBNJ Agreement reinforces the need for ABMTs and closer alignment between conservation and maritime operations. This means there may be potential new measures in sensitive regions, such as speed reductions, routing adjustments, and enhanced monitoring to mitigate impacts on biodiversity hotspots- and these would be mandatory for parties to the Agreement to comply with- but also to monitor and report on. However, the designation of such areas and how they align with existing frameworks remains to be seen.
One such hotspot, that may require such protection under the new Agreement is the Thermal Dome in the Eastern Tropical Pacific, a dynamic upwelling system that sustains rich marine life, including blue whales, sharks, and tuna. The Dome lies partly in the high seas and along major shipping routes to the Panama Canal, making it a focal point for discussions on balancing conservation with commercial activity.
The Thermal Dome, a climate-driven anomaly
So, what is the Thermal Dome? The Thermal Dome occurs as result of the action of the trade winds, the marine currents and the displacement of the Intertropical Convergence Zone in the Eastern Tropical Winds. These winds push the top layer of the ocean away from the coast and brings deep cold waters to the surface. This process creates a cyclonic circulation system, known as upwelling, or a dome effect. Unlike other seasonal upwelling areas, the Thermal Dome is a permanent upwelling system that persists year-round. The Thermal Dome shifts in size and location depending on time of year and climatic phenomena such as El Niño and La Niña. Despite its shifting nature it is mostly in the high seas but can also cover the territorial and coastal waters of five countries- truly being transboundary in nature.
But what makes it special from a biodiversity perspective? The cold, deep water bought to the surface is packed full of nutrients. These nutrients are essential for the growth of phytoplankton, species which are the basis of all marine food webs. This upwelling enables an ecosystem to emerge and creates one of the most productive and valuable marine ecosystems in the Pacific Ocean.
A diversity of species including tuna, sharks, turtles, and whales thrive here. Whales also migrate thousands of miles to feed in the Thermal Dome and this area is now designated as an Important Marine Mammal Area. This unique dome filled with rich biodiversity fuels the economy and contributes to the economic livelihoods of coastal communities. The Thermal Dome sustains local fisheries, sport fishing, whale related tourism and has an estimated value of 1.580 billion$ for the period of 2017-2022 .
The Thermal Dome is under threat
The Thermal Dome is prone to intense human activity and shipping is considered to be one of the most significant stressors on the Dome’s ecosystem. Major shipping lanes and trans-Pacific routes currently intersect with the area, creating a high-risk zone for marine mammals that feed and migrate near the surface. Proximity to the Panama Canal increases the number of transits through this sensitive area, which amplifies the risks to marine mammals of exposure to anthropogenic noise and ship strikes.
When it comes to noise- an estimated 90% of anthropogenic noise in the ocean is caused by ships. Underwater radiated noise (URN) from engines and propellers can mask vocalisations, disrupt navigation and feeding, and contribute to chronic stress of marine mammals. And it is not just URN that is of concern. A collision between a ship and a marine mammal can have devastating consequences and at 15 knots a strike has an estimated 80% probability of being fatal to a whale. In a recent analysis, from 2019 to 2021, nearly 1000 ships travelled at speeds faster than 15 knots through the Thermal Dome highlighting an area where potential improvements can be made to protect this area.
The Role of the International Maritime Organisation (IMO) and the Particularly Sensitive Sea Areas (PSSA) framework
The BBNJ Agreement introduces a global legal framework for using ABMTS- particularly the establishment of MPAs to protect areas on the high seas. For shipping a comparable framework is considered to already exist. PSSAs, established under the auspices of the IMO, aim to reduce risks from international shipping to ecologically significant areas by introducing protective measures such as routing, speed limits, and discharge controls. They are established through a rigorous process including scientific justification and approval mechanism by IMO member states.
In addition, the BBNJ Agreement explicitly states that it should not undermine existing sectoral bodies like IMO but rather promote coherence and coordination. This means that we might anticipate that a PSSA designation would be recognised as part of BBNJ’s implementation strategy for ABMTs and MPAs.
No PSSA has yet been designated on the high seas but there is potential for the Thermal Dome to be the first, given its important location in relation to global shipping traffic.
The Thermal Dome- the first high seas PSSA?
The MarViva SARGADOM Thermal Dome Project is on a mission to protect and manage the Thermal Dome. What makes this effort a unique and yet, challenging project is its location in the high seas. The maritime authority of Honduras is taking the lead in drafting the PSSA proposal for the high seas area of the Thermal Dome, supported by Guatemala, Panama, and Costa Rica.
An area must qualify to become a PSSA by meeting criteria such as exceptional ecological value, vulnerability, and exposure to human pressure, all of which the Thermal Dome meet. Central American maritime authorities have also been engaged in awareness and training sessions ensuring these protections thrive in practice and that the Thermal Dome doesn’t become a so called "paper park".
Existing examples like the Great Barrier Reef PSSA show how these measures effectively protect the ecosystem. Creating one in the high seas, however, will be an unprecedented step.
An opportunity for shipping?
Industry engagement is critical to the success of conservation measures in the Thermal Dome. Shipping has the unique opportunity to lead change in this region.
Sofar Ocean is a company dedicated to ocean data collection, real-time monitoring through buoy and sensor technologies, and marine conservation. For example, in the San Francisco Bay Area, they have deployed Spotter buoys equipped with AI-powered hydrophones enabling real-time whale detection and coordination with maritime authorities to help reduce vessel strikes on whales. Sofar Ocean also offers Wayfinder, a voyage intelligence platform that delivers industry-leading marine weather forecasts along with routing and planning guidance to the shipping industry.
With expertise in both voyage optimisation and marine mammal conservation, Sofar Ocean was an ideal partner for BIMCO. Using their new Wayfinder Voyage Simulator technology, they conducted two provisional analyses to assess how protective measures in the Thermal Dome might impact ship operations—one examining the effects of circumventing the area, and another examining the effects of slowing down within it.
The following links provide short, guided narratives outlining the potential the impacts on a ship undertaking a trans-Pacific voyage:
- Rerouting Analysis (around the Thermal Dome)
- Slow Down Analysis (reducing speed in Thermal Dome)
Based on these simulations, for this case, avoiding the Thermal Dome has negligible impacts on fuel costs and operational costs for a ship on a trans-Pacific voyage, supporting the hypothesis that making route adjustments for this area could strike a balance between being practical, cost effective and environmentally friendly.
Whilst this is just one case study, it shows the potential of harnessing data for decision-making in the establishment of protected areas and associated measures in areas beyond national jurisdiction. Of course, further in-depth impact assessments will be required as discussions advance.
What else are we doing related to the BBNJ Agreement?
As well as focusing on the Thermal Dome, we have also been involved in the GEF-UNDP-UNESCO-IOC Sargasso Sea Project, helping to bring the shipping industry into early discussions about sustainable ocean governance in another area of the ocean where balancing the conservation of biodiversity and industry is key. Shipping industry stakeholders have been invited to collaborate in consultation meetings, often hosted by BIMCO to discuss potential voluntary mitigation measures.
We are committed to ensuring our members voices are heard in the discussions related to any new marine protected areas on the high seas and that commercial realities and operational constraint are incorporated in the development of such projects.
DISCLAIMER
The information contained in this article is provided for general guidance and information purposes only. Whilst every effort is made to ensure that the information is accurate and up to date, BIMCO does not warrant, nor does it accept any responsibility or liability for the accuracy or completeness of the article or for any loss or damages which may arise from reliance on the information contained within.
Voices of the project
Sonia Jurado, Thermal Dome SARGADOM Project Coordinator, MarViva Foundation
The SARGADOM project focuses on two key high‑seas areas: the Sargasso Sea in the North Atlantic (“SARGA”) and the Thermal Dome in the Eastern Tropical Pacific (“DOM”). Its objective is to support the conservation of biodiversity and ecosystem services, while advancing hybrid approaches to ocean governance tailored to the specific characteristics of these sites. Both areas have been proposed as pilot sites under the BBNJ Agreement due to their dynamic nature and their ecological and economic importance.
The BBNJ Agreement not only strengthens the protection of biodiversity in areas beyond national jurisdiction but also upholds existing instruments and competencies to ensure coherence in global ocean governance. In doing so, it offers the shipping sector greater legal certainty, enabling it to pursue economic activity within a framework that promotes sustainability and safeguards high‑seas biodiversity and ecosystem services.
Kevin Fleming, Associate Director NLA International Ltd
Stakeholder Engagement is a critical part of the IMO PSSA process and so it has been a real privilege for NLAI to have been asked to deliver this aspect for the vitally important Thermal Dome Project. In this, and other Stakeholder Engagement delivery over the past few years for the Sargasso Sea Commission’s GEF Project, I have been struck by how forward leaning the international shipping industry have been. They have been both innovative and proactive in their approach to determining what measures they may be able to implement that will mitigate their impact on marine biodiversity in both these critically important high seas areas; with many of the proposed measures appearing to have negligible impact on their business.
Pieter Smit, Principal Scientist at Sofar
Our analysis suggests that protecting the Thermal Dome doesn't require choosing between conservation and commercial viability. The simulations produced using Sofar's ocean intelligence platform Wayfinder indicate that routing around the Dome adds roughly one percent to both voyage distance and time - about 80 nautical miles, five hours, and nine metric tonnes of fuel. When we can quantify the trade-offs with this level of precision, it creates a stronger foundation for conversations about what's operationally feasible.
Bev Mackenzie, Head of IGO Engagement, BIMCO
It is vital that any measures to converse biodiversity on the high seas related to the impact of shipping must be evidence-based, globally consistent, and operationally feasible- whilst affording the level of environmental protection required. The collaborative work undertaken with the Marviva Foundation, with NLA Associates and with Sofar Ocean is significant – because considering and engaging shipping
