Oceans cover roughly 71% of Earth’s surface, yet much still remains to be discovered about their vast depths. As scientists learn more about the ocean’s diverse and complex ecosystems, they are shattering preconceived notions and showcasing the interconnectedness of land and sea. Terrestrial wildlife needs habitat connectivity for survival, often relying on ecological corridors between parks and other protected areas. Thanks to research in recent years, it is becoming increasingly clear that habitat connectivity is just as important in the marine environment.
Marine ecological corridors, sometimes dubbed “blue corridors,” are complex ocean migratory highways that span considerable distances with little regard for political boundaries. For instance, in the Arctic, these blue corridors serve as crucial migration routes for species such as whales, enabling travel between feeding and mating grounds. These wide-ranging species traverse thousands of kilometers, using sea ice as a guide.
The health of the entire marine ecosystem depends on preserving these passageways. They allow species to fulfill their ecological roles and maintain delicate nutrient cycling—the system of transferring and recycling nutrients within ecosystems for living organisms and abiotic factors—the nonliving parts of the ecosystem. As humans’ scientific grasp of the ocean increases, so should efforts to protect and reestablish marine connectivity. These efforts will face mounting threats to wildlife and ecosystems, such as climate change, increased shipping traffic, deep sea mining, and overfishing.
The Center for Large Landscape Conservation and the IUCN-WCPA Connectivity Conservation Specialist Group (CCSG)—for which we serve as Secretariat—recognize marine connectivity as an essential strategy for global conservation and have played a key role in promoting and protecting it. The CCSG Marine Connectivity Working Group (MCWG) was formed in 2019 to meet the demand for connectivity conservation solutions that maintain, enhance, and restore the ecological connectivity of marine and coastal protected areas, marine biodiversity, and critical marine and coastal ecosystem services. MCWG is now ensuring that there is dedicated attention to connectivity science, policy, and management for marine and coastal areas.
The MCWG’s report titled “Marine Connectivity Conservation’ Rules of Thumb’ for MPA and MPA Network Design” stressed the role that interlinkages of ecosystems play in bolstering biodiversity, ensuring ecosystem resilience in a changing climate, and sustaining food systems. Developed specifically for conservation professionals and those working to implement marine policy, the report spotlights how integrating connectivity in conservation strategies and designating marine corridors for protection will help secure the longevity of marine species.
Connectivity research, in general, is much less advanced for the ocean than land, so this report was a step forward in protecting our oceans and is especially time-sensitive given the threat that unchecked human activity continues to pose.
Take the Maui dolphin for instance, New Zealand’s last endemic cetacean. The species faces pressures from boating and fishing, and therefore, only sixty remain in the world. In the upper Gulf of California, Mexico, the critically endangered vaquita porpoise is estimated to have dwindled to a population of only 10, suffering from habitat degradation and illegal fishing.
Last summer, members of the MCWG released a new paper for a special issue of the journal Marine Policy. “Marine Connectivity Conservation: Guidance for MPA and MPA Network Design and Management” summarized the report with a policy focus, providing invaluable insight into how marine protected areas can be designed and managed to enhance connectivity.
On the global stage, policy advancements in recent years emphasize the connectivity of our oceans as a primary concern. Adopted by the United Nations, the 2023 Agreement on the Conservation and Sustainable Use of Marine Biological Diversity of Areas beyond National Jurisdiction (BBNJ)—colloquially known as the High Seas Treaty—features ecological connectivity as a top priority and criterion for identifying Marine Protected Areas.
As of 2025, 112 countries have signed the agreement, and Greenpeace called it “the biggest conservation victory ever.” The High Seas Treaty aims to maintain marine ecosystem integrity across the world’s oceans for present and future generations, including through the establishment of “well-connected networks of marine protected areas.”
By conserving the critical pathways of oceans, we can continue to strengthen marine ecosystems, safeguarding the many services they provide Earth and protecting marine creatures from plankton to orcas. The policy and scientific developments made via the Center and our international partners reflect a growing consensus that connectivity is essential for the health of the high seas and critical for conserving the incredible biodiversity of our oceans.
Leaders around the world now prepare for the 2025 UN Ocean Conference convening in France in June, to advance the speed and scale to conserve our precious ocean in the face of the triple planetary crisis of climate change, biodiversity loss, and pollution.
Top photo: Orcas at the Kenai Fjords National Park in Alaska. Credit: NPS/Jim Pfeiffenberger
