What is the High Seas Treaty and Why Does It Matter?

You may have seen headlines recently about a new global treaty that went into effect just as news broke that the United States would be withdrawing from a number of other international agreements. It’s a confusing time in the world of environmental policy, and Ocean Conservancy is here to help make it clearer while, of course, continuing to protect our ocean.

What is the High Seas Treaty?

The “High Seas Treaty,” formally known as the Agreement on the Conservation and Sustainable Use of Marine Biological Diversity of Areas Beyond National Jurisdiction (BBNJ) Agreement, went into effect on January 17, 2026. We celebrated this win last fall, when the agreement reached the 60 ratifications required for its entry into force. (Since then, an additional 23 countries have joined!) It is the first comprehensive international legal framework dedicated to addressing the conservation and sustainable use of the high seas (the area of the ocean that lies 200 miles beyond the shorelines of individual countries).

To “ensure the conservation and sustainable use of marine biological diversity” of these areas, the BBNJ addresses four core pillars of ocean governance:

1. Marine genetic resources: The high seas contain genetic resources (genes of plants, animals and microbes) of great value for pharmaceuticals, cosmetics and food production. The treaty will ensure benefits accrued from the development of these resources are shared equitably amongst nations.
2. Area-based management tools such as the establishment of marine protected areas (MPAs) in international waters. Protecting important areas of the ocean is essential for healthy and resilient ecosystems and marine biodiversity.
3. Environmental impact assessments (EIA) will allow us to better understand the potential impacts of proposed activities that may harm the ocean so that they can be managed appropriately.
4. Capacity-building and the transfer of marine technology with particular emphasis on supporting developing states. This section of the treaty is designed to ensure all nations benefit from the conservation and sustainable use of marine biodiversity through, for example, the sharing of scientific information.

Why is the High Seas Treaty Important?

The BBNJ agreement is legally binding for the countries that have ratified it and is the culmination of nearly two decades of negotiations. Its enactment is a historic milestone for global ocean governance and a significant advancement in the collective protection of marine ecosystems.

The high seas represent about two-thirds of the global ocean, and yet less than 10% of this area is currently protected. This has meant that the high seas have been vulnerable to unregulated or illegal fishing activities and unregulated waste disposal. Recognizing a major governance gap for nearly half of the planet, the agreement puts in place a legal framework to conserve biodiversity.

As it promotes strengthened international cooperation and accountability, the agreement will establish safeguards aimed at preventing and reversing ocean degradation and promoting ecosystem restoration. Furthermore, it will mobilize the international community to develop new legal, scientific, financial and compliance mechanisms, while reinforcing coordination among existing treaties, institutions and organizations to address long-standing governance gaps.

How is Ocean Conservancy Supporting the BBNJ Agreement?

Addressing the global biodiversity crisis is a key focal area for Ocean Conservancy, and the BBNJ agreement adds important new tools to the marine conservation toolbox and a global commitment to better protect the ocean.

Ocean Conservancy’s efforts to protect the “ocean twilight zone”—an area of the ocean 200-1000m (600-3000 ft) below the surface—is a good example of why the BBNJ agreement is so important. The ocean twilight zone (also known as the mesopelagic zone) harbors incredible marine biodiversity, regulates the climate and supports the health of ocean ecosystems. By some estimates, more than 90% of the fish biomass in the ocean resides in the ocean twilight zone, attracting the interest of those eager to develop new sources of protein for use in aquaculture feed and pet foods.

Done poorly, such development could have major ramifications for the health of our planet, jeopardizing the critical role these species play in regulating the planet’s climate and sustaining commercially and ecologically significant marine species. Species such as tunas (the world’s most valuable fishery), swordfish, salmon, sharks and whales depend upon mesopelagic species as a source of food. Mesopelagic organisms would also be vulnerable to other proposed activities including deep-sea mining.

A significant portion of the ocean twilight zone is in the high seas, and science and policy experts have identified key gaps in ocean governance that make this area particularly vulnerable to future exploitation. The BBNJ agreement’s provisions to assess the impacts of new activities on the high seas before exploitation begins (via EIAs) as well as the ability to proactively protect this area can help ensure the important services the ocean twilight zone provides to our planet continue well into the future.

What’s Next?

Notably, the United States has not ratified the treaty, and, in fact, just a few days before it went into effect, the United States announced its withdrawal from several important international forums, including many focused on the environment. While we at Ocean Conservancy were disappointed by this announcement, there is no doubt that the work will continue.

With the agreement now in force, the first Conference of the Parties (COP1), also referred to as the BBNJ COP, will convene within the next year and will play a critical role in finalizing implementation, compliance and operational details under the agreement. Ocean Conservancy will work with partners to ensure implementation of the agreement is up to the challenge of the global biodiversity crisis.