Study: Over 300 migratory fish species are at risk globally

NORTH ATLANTIC

The European eel’s 3,700-mile journey is one of nature’s most extraordinary migrations. After hatching in the Sargasso Sea in the middle of the clockwise swirl of North Atlantic currents, the leaf-shaped larvae float east across the Atlantic, transforming into translucent glass eels on their way to the mouths of Europe’s and North Africa’s rivers. There they grow over decades, until a final transformation into silver eels compels them to return to the ocean to spawn.

The European eel is just one of more than 300 migratory freshwater fish in urgent need of international protections, according to a new report supported by WWF. Among the most at-risk vertebrates in the world, they depend on multiple connected habitats that span long distances and international borders. A single weak point—a dam, a suffocating algal bloom, water diversions that disrupt migration—can foil the entire journey. Population collapse can quickly follow.

“Cooperation across borders—including fisheries and habitat management, restoring or keeping rivers connected, and maintaining river flows—is critical,” says WWF-US’s Michele Thieme. In other words, migratory fish connect ecosystems, economies, and cultures—solutions to protect them must, too.