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Home » Defending the Ocean’s Hidden Highways: The Deep Sea at CMS COP15

Defending the Ocean’s Hidden Highways: The Deep Sea at CMS COP15

The deep sea, Earth’s largest and least explored habitat, is coming into sharp focus at a pivotal moment for global conservation. In 2026, governments will gather at the 15th Conference of the Parties (COP15) to the Convention on the Conservation of Migratory Species of Wild Animals (CMS) to make decisions that could shape the future of these vital ecosystems and the migratory species that depend on them.

Why Global Action Through CMS is Critical for the Deep Sea

CMS is a United Nations treaty, instrumental in protecting animals that cross international borders during their life cycles, including both marine and terrestrial species. For ocean migrants such as whales, sharks, tuna, sea turtles, and many others, this protection is especially critical. These animals rely on connected and healthy habitats spanning entire ocean basins, traveling through the waters of multiple countries and the high seas. 

As governments prepare to meet at COP15 from 23-29 March 2026 in Campo Grande, Brazil, momentum is building to protect vital deep-sea ecosystems and the migratory species that depend on them.

A Proposed Resolution and Decision on Conserving Seamount Ecosystems 

Seamounts are biodiversity hotspots and essential stepping stones for migratory species. These underwater mountains provide essential feeding grounds, breeding sites and navigational landmarks for whales, sharks, rays, tuna and many other species. 

The CMS Resolution and Decision (UNEP/CMS/COP15/Doc.25.3.3) proposed by Monaco and Panama on Conserving Seamount Ecosystems provides a framework for coordinated action to protect these critical habitats across jurisdictions.

The Resolution and Decision seeks to:

  • Protect seamounts from destructive fishing practices in order to strengthen ecological connectivity
  • Conserve critical habitats for migratory species, and advance species recovery
  • Urge CMS Parties to prioritize seamount protection both within and beyond national jurisdiction to enhance the conservation status of migratory species; 
  • Protect the ecological integrity of seamount ecosystems
  • Promote cooperation with regional mechanisms, international instruments and processes, and relevant organizations. 

This resolution and decision provides a crucial framework for coordinated international action to protect these fragile ecosystems across national waters and the high seas, and the DSCC strongly supports it.

Find out more in the DSCC’s briefing document in support of the resolution and decision proposed by Monaco and Panama here:

 

The risks of deep-sea mining for migratory species

During CMS COP14 in February 2024, Parties recognised the serious threat that deep-sea mining poses to migratory species and their habitats and adopted two key decisions on deep-sea mining: 

  1. Resolution 14.6 which urges member countries not to engage in, or support, deep-sea mining until sufficient and robust scientific information has been obtained to ensure that deep-sea mining exploitation activities do not cause harmful effects on migratory species, their prey and ecosystems. 
  2. Decision 14.51 asks the CMS Scientific Council to develop a report on the state of knowledge of the impacts of deep seabed mineral exploitation activities on migratory species, their prey and their ecosystems, including identifying knowledge gaps that should be addressed. 

Growing scientific evidence shows that deep-sea mining could disrupt migration routes, alter prey availability and expose species to unprecedented levels of noise and pollution. 

Key resources