By: Sarah Stone
New Zealand has its fair share of unusual wildlife moments, and today, we would like to highlight the oddly mesmerizing annual eel migration. Imagine driving down a quiet road only to find it covered in hundreds of slithering eels, all determined to get to the other side. It sounds like something out of a nature documentary, but it’s an actual event that happens like clockwork every year!
The longfin eels (Anguilla dieffenbachii) are one of New Zealand’s most fascinating native species. They spend decades living in the country’s freshwater lakes, rivers, and streams before making an epic, once-in-a-lifetime journey to spawn. When the time comes, they leave their freshwater homes and start heading toward the ocean, traveling thousands of miles to the deep waters of the Pacific.
Why Do They Cross the Road?
Eels are excellent navigators, but they haven’t evolved for modern infrastructure. As they make their way downstream, they can encounter roads, culverts, and other human-made obstacles that weren’t part of the landscape when their ancestors made this trip.
If a body of water is just on the other side, they won’t let a little pavement stop them. They’ll slither right over, undeterred by the fact that they’re fish out of water—at least temporarily. Their ability to absorb oxygen through their skin allows them to survive on land for short periods, making these road crossings a strange but necessary detour.
Where Are They Going?
The ultimate goal? The Tonga Trench—an underwater canyon that can take five to six months for the eels to reach. Scientists believe this is the final destination for New Zealand’s longfin eels, where they spawn once and then die, completing a migration that’s been happening for generations.
This is where things get mysterious. No one has witnessed a longfin eel spawning in the wild. The exact route, timing, and details of the process remain unknown, but it is clear that these eels follow an ancient instinct, and nothing—not even a road—will stop them.
The eel migration typically happens during late summer and early autumn (February to April in New Zealand), especially after heavy rains. The most well-known crossings tend to occur in wetland areas where eels have to navigate between rivers, ponds, and lakes.
The Bigger Picture: Why This Matters
New Zealand’s longfin eels are essential to the country’s ecosystem and cultural heritage. Māori have eaten the eels as a staple of their diets, and have created artwork, songs, and even sacred ponds for the eels for centuries.
Sadly, habitat destruction, pollution, and overfishing have led to a decline in their population. Events like road crossings highlight how much human development has altered their natural migration routes.
A road packed with migrating eels isn’t something you see every day, but in New Zealand, it’s a reminder of just how incredible the natural world can be. These creatures are on a mission that’s been part of their species’ survival for thousands of years, and even in the face of modern obstacles, they just keep going.
About the Author
As the editor in chief of Frayed Passport, my goal is to help you build a lifestyle that lets you travel the world whenever you want and however long you want, and not worry about where your next paycheck will come from. I've been to 20+ countries and five continents, lived for years as a full-time digital nomad, and have worked completely remotely since 2015. If you would like to share your story with our community, or partner with Frayed Passport, get in touch with me at sarah@frayedpassport.com!
Featured image by Gusmonkeyboy on Wikimedia Commons.
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