Marine species navigate the global ocean via a network of "invisible highways"—migratory corridors and current systems—that are essential for survival but remain largely unprotected by international law.
While traditional marine conservation focuses on Marine Protected Areas (MPAs) that designate specific, static geographical coordinates as "no-take" zones, these boundaries often fail to protect species that move...
The vulnerability of these pathways is particularly acute in biodiversity hotspots such as the Coral Triangle and the waters surrounding Indonesia.
Marine species navigate the global ocean via a network of “invisible highways”—migratory corridors and current systems—that are essential for survival but remain largely unprotected by international law. These corridors, which include both physical ocean currents and biological migration routes, facilitate the movement of whales, sharks, tuna and sea turtles between feeding and breeding grounds.
While traditional marine conservation focuses on Marine Protected Areas (MPAs) that designate specific, static geographical coordinates as “no-take” zones, these boundaries often fail to protect species that move across thousands of miles of open water. Because these migratory highways shift based on temperature, prey availability, and current strength, static boundaries often leave animals vulnerable once they exit a protected zone.
The vulnerability of these pathways is particularly acute in biodiversity hotspots such as the Coral Triangle and the waters surrounding Indonesia. The Indonesian Throughflow, a critical current system that transports warm, low-salinity water from the Pacific Ocean to the Indian Ocean, serves as a primary conveyor belt for nutrients and larvae, supporting some of the most diverse marine ecosystems on Earth.
Threats to Migratory Corridors
Human activity frequently overlaps with these invisible highways, creating high-risk zones for marine megafauna. One of the most immediate threats is the intersection of shipping lanes with migratory paths. Ship strikes are a leading cause of mortality for endangered whale species, as large vessels often travel at speeds that make it impossible for animals to avoid collisions.
Acoustic pollution further disrupts these corridors. Anthropogenic noise from commercial shipping, seismic surveys for oil and gas, and naval sonar interferes with the low-frequency communication that many cetaceans use to navigate and socialize. When these “highways” become too noisy, animals may abandon traditional routes, potentially leading them into areas with less food or higher predation risks.
Climate change is altering the physical structure of these highways. Rising sea temperatures and changes in salinity are shifting the location and intensity of major ocean currents. As these currents move, the species that rely on them for transport or as indicators for migration must adapt. If the biological timing of migration no longer aligns with the peak availability of prey—a phenomenon known as phenological mismatch—population declines can occur.
The Limitations of Static Protection
The current global approach to ocean protection relies heavily on the MPA model. While effective for protecting sedentary species like coral reefs or seagrass beds, this model is ill-suited for the fluid nature of the open ocean. A species may be protected while within a specific sanctuary, but it faces full exposure to industrial fishing and shipping the moment it crosses an invisible line into the high seas.
Dynamic Ocean Management
many of these highways extend into areas beyond national jurisdiction (ABNJ). In these international waters, regulation is fragmented, and enforcement is minimal, making it difficult to implement cohesive protection strategies for species that traverse multiple national boundaries.
Dynamic Ocean Management
To address these gaps, researchers and policymakers are advocating for Dynamic Ocean Management (DOM). Unlike static MPAs, DOM uses real-time data—including satellite tracking of ocean temperatures, chlorophyll levels, and acoustic monitoring—to create flexible protection zones that move in tandem with the animals.
Dialogue Earth ocean highways
Under a dynamic system, shipping lanes could be temporarily shifted or speed limits imposed in specific areas when sensors detect the presence of migrating whales. This approach allows for the protection of the “highway” without permanently closing vast areas of the ocean to commercial activity.
The challenge is that our legal frameworks are based on borders and boxes, while the ocean functions as a connected, fluid system. Protecting a species requires protecting the path it takes, not just the place where it sleeps.Dialogue Earth
An Ocean in Motion: NASA's Mesmerizing View of Earth's Underwater Highways
Implementing such a system requires international cooperation and the sharing of data between governments, shipping companies, and scientific institutions. The adoption of the High Seas Treaty, finalized in 2023, provides a potential legal framework for establishing protected areas in international waters, though the transition from treaty to enforceable dynamic management remains a significant logistical hurdle.
The preservation of these invisible highways is central to maintaining the ecological balance of the global ocean. By ensuring that migratory species can move safely between critical habitats, the resilience of marine ecosystems against climate change and overexploitation is strengthened.
