Just when you thought you’d seen it all, meet a fish that can cross a road and climb a wall — and might be settling in a stream near you.
Each year, hundreds of thousands of juvenile American eels migrate from the Atlantic Ocean into the Hudson River and its tributaries — including the Wappinger, Roeliff Jansen Kill, Saw Kill and Crum Elbow — where they may live for up to 50 years.
They’ve been making this journey for millions of years. In a tradition now 25 years old, school groups, families and conservationists have been helping them along — counting the baby eels, known as glass eels, as part of a community science effort.
The Hudson River Eel Project, a program of the state Department of Environmental Conservation’s Hudson River Estuary Program, now draws as many as 1,000 volunteers each spring. From Staten Island to Hannacroix, participants don borrowed waders and fan out across 13 monitoring sites in nine counties, helping count, weigh and track the annual migration.
“Local volunteers are absolutely essential,” said Chris Bowser, education coordinator for the Hudson River Estuary Program and co-leader of the eel project. “We wouldn’t be able to do our work without them.”
You may think of them as slippery or strange, but eels have aroused the curiosity of thinkers and philosophers from Aristotle to Sigmund Freud, whose first published paper in 1877 explored the sexual life of eels. In New Zealand, Māori communities revere them as guardians of freshwater. Eels also played a role in early U.S. history: when the Pilgrims of Plymouth Colony faced starvation during the harsh winter of 1621, the Wampanoag taught them how to catch the slippery fish.
Eels loom large in the public imagination for two reasons: they are miracles of nature, and they remain shrouded in mystery despite decades of scientific inquiry. Among their jaw-dropping achievements is the ability to move across land. They are often found in lakes and ponds that have no connection to a river. We now know that they can reach such a pond by building bridges with their bodies. Eels have even been observed climbing vertical walls, by forming a braid with their intertwined bodies to reach water. “Eels can overcome a lot of obstacles,” said Julie Hart, a Milan resident and education director at the Dutchess Land Conservancy. “They are really good at doing that.”
Not so long ago, eels ventured up the Mississippi and its tributaries throughout the Midwest and East. In fact, they were considered native to two-thirds of the continental United States. But over the past 50 years, habitat loss, pollution, and the construction of dams have taken a toll. Another factor, according to the writer James Prosek, author of the book “Eels”, is the “gold rush” in which millions of glass eels were exported to the Far East for consumption in sushi. The gold rush peaked in the 1990s, when environmentalists sounded the alarm that eels were approaching extinction.
The export market was curtailed but today eels continue to be listed as “depleted” in 14 states by the Atlantic States Marine Fisheries Commission. “Eels are no longer in freefall, but their numbers remain much, much lower than historical populations,” said Chris Bowser, education coordinator for the Hudson River Estuary Program and co-leader of the Hudson River Eel Project. “There used to be a lot more eels in a lot more rivers here. So we have a long way to go until they are restored.”
The severe decline of eels makes it especially important to monitor their health, Bowser said. “Their observations contribute to coastwide monitoring of the health of the American eel and its role in our waterways. It’s a really unique use of volunteer-collected data used directly for science.”
Fourteen states from Florida to Maine run similar programs.
“We call eels the ambassador species,” said Bowser. “One of the most important facts to understand about the environment is that everything is connected. Eels are a perfect example of that. They connect the ocean to the estuaries to the cities, the rivers, the streams and the land around them. They also bring nutrients upstream at the critical moment when other fish are just starting to breed.”
The closest monitoring site to Pine Plains is at Crum Elbow Creek in Hyde Park. On May 15, the Dutchess Land Conservancy will host a one-hour training session for volunteers interested in tracking eel migration. The session will be held in person and on Zoom, and a recording will be available for those who prefer to watch later.
Attending the training qualifies volunteers to help monitor an eel ladder in Hyde Park, where eels make their way upstream each spring. Volunteers check the site twice a week through the summer, monitoring fyke nets — specialized nets used to catch eels and other fish at the mouth of tributaries.
Equipped with provided gear, volunteers also assist in transporting eels over barriers by catching, counting and weighing them below an obstacle, then releasing them upstream so they can continue their journey through Dutchess and Columbia County streams.
“The Dutchess Land Conservancy is excited to support the community science eel monitoring program,” said Hart. “It’s a unique opportunity for people to track young eels coming through our area and contribute directly to urgently needed science.”
Eels tend to grab people’s imaginations early.
“At first, a lot of kids are unwilling to touch these squirmy, slimy things,” said Hart who participates in the monitoring. “But once they find out the amazing things eels do, their curiosity grows, and then you can’t hold them back.”
Colleen Lutz, an Ancram Town Board member and biologist with the New York State Natural Heritage Program was in her backyard by a tributary to Punch Brook a few years ago when she heard shouts. “It was my son Tim and my daughter Katie, shouting, ‘Mom! We caught a snake!’ The snake turned out to be a full grown eel. I was amazed.” After that encounter, the family began participating in eel counts.
“Eels are a gateway,” said Hart. “They open up a whole new world for people.”
“It’s amazing how many young people start out monitoring eels and then become teachers and environmental educators,” added Bowser. Some volunteers started monitoring the fish while in middle school and high school, and are still at it as adults.
Asked if eels venture as far East as Pine Plains, Bowser said, “You’d be surprised. They are found even further from the Hudson. When you find them that far out, they are very large, they’re the apex predator.”
“Theoretically, eels should be in all of our Dutchess and Columbia country tributaries, and historically they were,” said Hart. “My guess is they are in the Roe Jan, despite its dams, but we need to do a count. We just don’t track them in every river.”
Patrick Hurley, a Salt Point plumber, has tracked eels in Wappinger Creek by the Salvato mill south of Stanfordville. “They’re in there,” he said.
Bowser became interested in eels because of their remarkable perseverance. “Despite the dams, the diversions, all the hazards, and the distances these little six inch eels have to cover, they still make it here every year,” he said. “It’s amazing what these species can do.”
He admits to being attracted to the underdog status of eels. “A lot of people don’t really like them because they are like snakes to them. But the more eels I see, the happier I am. In a rough world, just to know that there are thousands of little river heroes among us that don’t care about us makes me happy.”
The freshwater eel evolved from an ancestor 50 million years ago. It has survived multiple ice ages, volcanoes, and continental drift. Its first peculiarity is that unlike salmon and other migratory fish that spawn in freshwater and move to salt water to live out their lives, the eels are the opposite. They spawn in salt water and live their lives in freshwater ponds, estuaries and rivers.
Eels are born a thousand miles away in the heart of the Bermuda Triangle, in an eddy in the Atlantic Ocean called the Sargasso Sea. Scientists speculate they choose this spot east of Bermuda because it has the perfect temperature and salinity levels. Nobody’s been able to observe them spawning, or even find the spot where they reproduce. In February, eel larvae hatch from eggs suspended in the ocean and drift up the Gulf Stream. At this point, eels go through the first of two metamorphoses in their life cycle, transforming into glass eels, tiny fish that are transparent except for two little dots of their eyes. Somehow, these fish the size of a toothpick figure out exactly when to leave the Gulf Stream and swim Westward towards our local rivers, where they arrive in May. It takes them about a year to get there – no-one knows for sure.
In New York, the glass eels are first spotted by volunteers in nets on the southern Hudson River, closer to New York City. Later in May they begin appearing in Dutchess and Columbia rivers that serve as tributaries to the Hudson, and start growing in length. “They come off the Hudson looking for a place to call home,” said Hart.
They live among us for 40 or more years in local streams, growing up to three feet long and darkening in color. “They are hard to spot,” said Lutz. “They spend their time in mucky river bottoms, feed at night and vanish if approached.”
Through their long and eventful lives, eels play a critical role in the food chain, initially serving as a food source for shorebirds, hawks, and larger fish. As the eels grow and age in our rivers, they become predators, reaching the top of the food chain and keeping the ecosystem in balance. “Eels are carnivores,” said Hart. “They can eat anything.”
One of the main reasons to count glass eels is that they are a canary in a coal mine. Monitoring eel populations can help scientists assess the impacts of habitat changes, pollution, and other factors on stream health.
“American Eels are reliable indicators of the health of Dutchess and Columbia County streams,” said Hart. “They are very sensitive to dissolved oxygen levels in a waterway,” said Hart. “They are sensitive to pollution.
“Eels also help us understand the health of the lands around our rivers because you can tell the health of the land by the health of the water.”
After several decades, a miracle of nature takes place in local streams. In a process scientists call “silvering,” the eels in Dutchess and Columbia counties as well as in rivers up and down the East Coast, enter a second metamorphosis. Their eyes grow larger to allow them to see in the ocean’s dark, their fins become longer and stronger to surmount the ocean’s currents, and, most incredibly, they absorb their own digestive tracts so they no longer need to eat, and then they grow a reproductive tract. Thus equipped, every fall they journey back to where they were born in the Sargasso sea to mate and die.
For 175 years, scientists have been puzzling over what triggers this metamorphosis. But, as often happens with eels, science draws a blank. “It’s a complete mystery how eels manage to find their way from our estuaries and tributaries back to the open ocean where there are no markers, and find the exact spot where they were born,” said Lutz.
“One of the most wonderful things about these bizarre animals is how little we know about them,” said Hart. “They remind us that there are things in nature that are not easily explained.”
Volunteer to work with one of the world’s most mysterious creatures and help the health of streams and rivers by signing up here.