What You Didn’t Know About Freshwater Eels in New York Rivers

Beneath the surface of New York’s rivers, lakes, and estuaries lives one of the most mysterious and misunderstood creatures in North America—the freshwater eel. Sleek, serpentine, and secretive, these eels have fascinated scientists, anglers, and storytellers for centuries. While they might resemble snakes at first glance, freshwater eels are fish—complex, migratory, and vital to the ecosystems they inhabit.

From the mighty Hudson River to the serene waters of the Finger Lakes, eels have thrived for thousands of years, silently connecting inland waterways to the distant depths of the Atlantic Ocean. Yet few people truly understand their incredible journey—a life cycle that spans continents, currents, and even decades.

This article explores what you didn’t know about freshwater eels in New York rivers—their biology, strange behaviors, ancient migration routes, and the surprising ways they impact both nature and human culture. By the end, you’ll see these slippery survivors not as slimy nuisances, but as living symbols of endurance and mystery.

The Freshwater Eels of New York

Species Overview

The most common species found in New York is the American eel (Anguilla rostrata), a migratory fish native to the entire Atlantic coast of North America. Though often overlooked, this species plays an important role in river ecosystems and has one of the most complex life cycles of any fish on Earth.

American eels inhabit nearly every major river system in New York, including:

• Hudson River
• Mohawk River
• Delaware River
• St. Lawrence River and Lake Ontario
• Streams of Long Island and the Catskills

Physical Description

Adult eels are long and cylindrical, with smooth, slimy skin that ranges from olive-green to dark brown. They typically grow between 2 and 4 feet in length, though large females can exceed 5 feet. Unlike most fish, eels lack pelvic fins, and their dorsal and anal fins form a continuous ribbon around the body, giving them their snake-like appearance.

The Life Cycle: One of Nature’s Greatest Mysteries

Born in the Bermuda Triangle

All American eels begin life in a mysterious place called the Sargasso Sea, a region of the Atlantic Ocean near Bermuda. Scientists still know little about their exact spawning grounds—no one has ever observed American eels mating in the wild.

Female eels release millions of eggs into the deep blue waters, where males fertilize them. The eggs hatch into leptocephali, transparent, leaf-shaped larvae that drift on ocean currents for months.

The Journey Home

These larvae travel thousands of miles on the Gulf Stream, eventually reaching the East Coast of North America. By the time they reach the continental shelf, they’ve transformed into glass eels—small, transparent juveniles about the length of a pencil.

In early spring, glass eels arrive at New York’s estuaries, such as the Hudson River Estuary, where freshwater meets saltwater. They begin their upstream journey, turning into elvers as they adapt to freshwater.

Growing Up in New York Rivers

Once settled in freshwater, eels enter the yellow eel stage, where they spend anywhere from 5 to 25 years growing and feeding. Males usually remain smaller and stay closer to coastal areas, while females migrate farther inland into rivers and lakes.

When it’s time to reproduce, the eels undergo an extraordinary transformation into silver eels, developing large eyes and stronger muscles for the journey back to the Sargasso Sea—a one-way trip to the place where their lives began.

Strange and Fascinating Behaviors

1. Masters of Migration

American eels are one of the few fish species that migrate from freshwater to the ocean to spawn, a pattern called catadromy. This makes them the exact opposite of salmon, which migrate from the ocean to freshwater.

During migration, silver eels travel mostly at night, navigating by magnetic fields, moonlight, and temperature cues. Some travel over 3,000 miles without eating, relying solely on stored fat.

2. They Can Climb Waterfalls

Juvenile eels have the remarkable ability to climb over obstacles using their muscular bodies and mucus-coated skin. They can slither over wet rocks, dams, and even small waterfalls to reach upstream habitats. This climbing ability allows them to populate even the smallest tributaries of New York’s river systems.

3. Eels and Electricity

Though American eels don’t produce electric shocks like their South American cousins (Electrophorus electricus), they are highly sensitive to electrical signals. They use weak bioelectric fields to detect prey and navigate murky waters.

4. Nocturnal Hunters

Eels are primarily nocturnal, spending daylight hours hiding under rocks, logs, or in muddy burrows. At night, they emerge to hunt for worms, crustaceans, fish, and amphibians. Their sense of smell is extremely acute—among the best of all freshwater fish.

The Importance of Eels in New York’s Ecosystems

Keystone Connectors

Eels play a vital role in river ecosystems by transferring nutrients between freshwater and marine environments. As both predator and prey, they help regulate populations of smaller fish and aquatic invertebrates.

A Favorite Food for Many

Eels are an important food source for birds like herons, ospreys, and bald eagles, as well as mammals like raccoons and otters. Their abundance helps sustain these predators throughout the year.

Soil and Sediment Engineers

By burrowing and feeding, eels aerate river sediments, helping maintain oxygen levels and improving overall water quality.

Eels and People: A Long History

Cultural Significance

Eels have been an essential resource for Indigenous peoples in New York for thousands of years. The Haudenosaunee (Iroquois) and Lenape tribes used eels for food, medicine, and ceremonies. Smoked or dried eels were also traded widely as a valuable protein source.

Colonial and Modern Fisheries

In the 18th and 19th centuries, eel fishing became an important industry in New York’s Hudson Valley. Fishermen used woven traps called eel pots to catch migrating silver eels. Today, small-scale eel fisheries still exist, though heavily regulated to protect declining populations.

Culinary Interest

In some parts of the world, especially Japan and Europe, eel is a delicacy known as unagi or anguilla. American eels caught in New York were once exported internationally, but strict conservation laws have reduced commercial harvests to ensure sustainability.

Threats to Freshwater Eels in New York

1. Dams and Habitat Barriers

Dams are among the greatest threats to eel populations. Many of New York’s rivers have man-made barriers that block migration routes. Without access to upstream habitats, juvenile eels lose critical feeding and breeding grounds.

To counter this, agencies like the New York State Department of Environmental Conservation (DEC) have installed eel ladders—structures that allow young eels to climb over dams safely.

2. Pollution and Contamination

Eels are highly susceptible to pollutants like PCBs (polychlorinated biphenyls) and heavy metals because of their fatty tissues and long lifespans. Contaminants accumulate in their bodies, posing risks to both the eels and predators that consume them.

3. Overfishing

Glass eels are highly valuable in global seafood markets, especially in Asia. Overharvesting during their migration has caused population declines along the Atlantic Coast.

4. Climate Change

Warming waters and shifting ocean currents threaten the eels’ long migration routes to the Sargasso Sea. Even slight changes in current patterns could disrupt their navigation and spawning success.

Conservation Efforts in New York

The Hudson River Eel Project

Launched by the DEC and Hudson River National Estuarine Research Reserve, this program engages citizen scientists to monitor eel migration each spring. Volunteers count, measure, and release glass eels to help track population trends and improve conservation strategies.

Eel Ladders and Fish Passages

Dozens of eel ladders have been built along the Hudson, Mohawk, and Delaware Rivers, allowing thousands of young eels to bypass dams each year. These structures have become a model for similar projects across the East Coast.

Educational Outreach

Programs in schools and nature centers teach students about eel ecology and their critical role in maintaining river health. Increasing public awareness has become one of the most effective tools for protecting this mysterious fish.

Myths and Misconceptions About Eels

Myth	Truth
Eels are snakes.	False. They are fish with gills, fins, and scales.
Eels reproduce in rivers.	False. All American eels spawn in the Sargasso Sea.
Eels are harmful or poisonous.	False. They are harmless and beneficial to ecosystems.
Eels can shock you like electric eels.	False. American eels do not generate electricity.
Eels are invasive in New York.	False. They are native and crucial to local rivers.

Strange and Little-Known Facts About Freshwater Eels

1. They can live over 30 years in captivity—and sometimes longer in the wild.
2. They can survive short periods out of water, absorbing oxygen through their skin when moist.
3. Eels migrate mostly at night, guided by moon phases and temperature.
4. Female eels grow larger than males, sometimes twice the size.
5. No one has ever witnessed them spawning in the wild.
6. Eels can travel across wet grass between ponds or streams during heavy rain.
7. Their migration from New York to the Sargasso Sea may take several months, guided purely by instinct.

The Future of Eels in New York Rivers

Recovery and Hope

Thanks to conservation efforts and environmental regulations, eel populations in the Hudson River and its tributaries have shown signs of recovery. Reconnecting waterways, reducing pollution, and protecting migratory paths remain top priorities.

Role in Restoring Ecosystems

Restoring eel populations also helps revive entire river ecosystems. As eels return, so do the birds, fish, and mammals that depend on them. Their comeback represents not only ecological balance but also the success of community-based conservation.

Global Collaboration

Because eels migrate across nations and oceans, protecting them requires international cooperation. The U.S. and Canada work closely with other Atlantic nations to monitor eel populations and regulate fishing quotas.

FAQs About Freshwater Eels in New York Rivers

Are freshwater eels dangerous?

No. They are shy and avoid humans. Their slimy coating protects them from infection, not used for attack.

What do eels eat?

They feed on small fish, insects, crustaceans, worms, and amphibians.

Can eels climb dams?

Yes, especially young eels (elvers). They can slither up damp surfaces using their muscular bodies.

How far do they travel?

From New York’s rivers to the Sargasso Sea—over 2,000 miles away.

Are eels good to eat?

Yes, when properly prepared. They are nutritious and widely consumed worldwide.

How can I help protect eels?

Support conservation projects, reduce water pollution, and advocate for dam removal or fish passage installations.

Conclusion

The freshwater eels of New York are living testaments to nature’s resilience and mystery. From their hidden origins in the Sargasso Sea to their long sojourns in the Hudson and beyond, their story is one of migration, transformation, and survival.

Though often overlooked, eels connect oceans to rivers, ecosystems to people, and the past to the present. Protecting them means protecting the lifeblood of New York’s waterways.

So next time you stand beside a river and see a ripple beneath the surface, remember—you may be sharing that moment with one of the planet’s most remarkable travelers, an eel on its timeless journey between worlds.