The American eel is an unlucky and undeniably slippery hero. Sometimes thought of as slimy or scary, it’s an underdog in the conservation world. An animal existing in frighteningly low abundance compared to its early 20th century glory. An animal that has the power to instantly capture the imagination with its mysterious and obscured life cycle.
But first, I need to share one of my favorite science acronyms: BOFFFFs. Big Old Fat Fertile Female Fish. In the eel world, it’s the biggest, oldest females that are able to reproduce the most. And Lake Ontario is like the headquarters of the eel queens. As a result, the lake is critical habitat for the global population of American eels. It’s home to a mostly female, mostly large, in charge and long lived group of American eels. These eels spend most of their lives in Lake Ontario, but their whole life cycle is unbelievable. It involves multiple complete transformations, thousands of miles of migration, numerous death traps and mystery sex.
They complete two incredible migrations in their lifetime. For this story, we drove 500 miles of it. We drove from Toronto to Quebec City, Canada. Starting near the western shores of Lake Ontario and following the northern coast out to the St. Lawrence River, stopping just before it reaches the North Atlantic and just after our budget ran out.
Along the way, we met zookeepers, scientists, and community members who are all working to better understand and conserve the eel in different ways.
That’s because the Lake Ontario eels are in trouble. They might seem like they could easily play the villain in a Disney movie, and while Ursula’s sidekicks, Flotsam and Jetsam, are moray eels, I have to tell you that those are not “true eels.” And in this story, our hero is the eel, and the villain we’ll meet later on.
Travels with eels
Before we left for our trip, I talked with Lisa Holst, the Rare Fish Unit Leader at the New York State Department of Environmental Conservation.
“If you think about a large eel that's been resident in Lake Ontario, eating and doing her thing, chilling with her besties, for a couple of decades,” Holst said. “By the time she gets back out to the Sargasso Sea, she is full of more eggs than, say, a smaller eel that might be coming from a population closer to the Sargasso Sea.”
Lake Ontario eels swim all the way out through the St. Lawrence River to a place in the North Atlantic called the Sargasso Sea. It's bounded by currents, topped with mats of floating seaweed, and just for added drama, overlaps the Bermuda Triangle. It’s millions of square miles.
Lake Ontario eels are mostly female and live about 15-40 years. It’s a combination of geographical and environmental factors that explains why they’re all female. The BOFFFFs in Lake Ontario are historically, critically important for the whole species globally. American eels are one breeding population from Greenland all the way to Venezuela. They live in accessible rivers and lakes in between, until they’re ready to spawn. And then they go out to sea. The males of the species tend to live in freshwater habitats closer to shore. They do not live as long and are typically smaller in size. From their nearshore habitat, their migration is simpler; shorter.
Every summer, all of the eels that are ready to reproduce make an incredible journey from their freshwater habitats out to the Sargasso Sea. To mate and spawn, supposedly.
“Nobody's ever actually seen it happen that I know of. But they get together as one giant group and they spawn and that's it. They spawn once and they die,” said Holst.
In tracking studies, scientists have seen tagged eels go to the Sargasso. They’ve recorded the eels diving hundreds of meters deep. The theory is that they’re mating deep in the ocean in the Sargasso Sea, where it’s dark and cold and secret. Scientists are assuming this because they do not see the adults again. And then in the same general area, teeny tiny eel larvae start to appear.
And those itty bitties have to now swim and drift on the Gulf Stream, all the way back to their freshwater habitats in North and South America. As they go, they're growing and eating and transforming, so that by the time they reach freshwater they're looking more eel-like and more solid.
Eye contact with eels
Sam Murchie is the lead keeper for fishes at the Toronto Zoo. We crowded around the eel exhibit with him, while visitors walked by and stared curiously at what appeared to be an empty tank with a pile of logs. But after a few minutes, the tangle of eels started to unwind. And soon, pairs of large eyes on petite heads attached to long, wide bodies, stared out at us. Unblinking and inscrutable, one eel in particular held my gaze without hesitation.
“They're a gift that keeps on giving as far as just how fascinating they are 'cause you can spend a professional life just thinking about their life cycle and never even getting into the migratory aspect,” said Murchie.
After our first eel sighting at the zoo, we continued our own migration, driving along the Lake Ontario coast. We stopped to stand on the store a few times, staring into the endless lake horizon. Its surface was as opaque as ever, concealing an unknown number of female eels, housing an entire ecological drama that remained invisible to us on shore.
The first day we drove about 100 miles before stopping in a small town on the northeastern coast of Lake Ontario. The next morning, we woke up to an inch of snow frosting everything. Unprepared for this late winter storm, we had to borrow an ice scraper from hotel reception and grit through 160 miles of low visibility snowy conditions. A mandatory stop at a petrol station with a Tim Hortons' was essential.
Conversations with eels
We arrived, late, to the St. Lawrence River Institute. It’s a nonprofit in Cornwall, Ontario, founded in partnership with the Mohawk Council of Akwesasne. The building sits right at the St. Lawrence River’s edge. The conference room windows held a view of the lake, and the snow here had not even stuck, so we had a clear view of the grassy banks.
“This is one of the most important habitats for American eel in the world,” explained Mary Ann Perron, an aquatic ecologist at the institute.
The St. Lawrence River comes out of Lake Ontario, dividing the U.S. and Canada before going out to the Atlantic Ocean. Prior to 1985, hundreds of thousands, sometimes over a million eels took that route each year.
“In 1986, that number crashed significantly. So there's been a huge loss in the abundance of American eel for the river,” said Perron.
The eels passing through the St. Lawrence River have been through considerable human impacts, including heavy pollution of mercury and PCBs, in addition to fishing, climate change, and invasive species. Part of Perron’s work has been digging into the available data and published research: what the hypotheses are for the crash of the eel and which ones have real evidence behind them.
“So in the St. Lawrence watershed, they estimated that there were 8,411 dams,” said Perron.
There are two major hydroelectric dams in this part of the river. In 1932, the Beauharnois dam went online, followed in 1958 by the Moses Saunders dam. Moses Saunders is an internationally run dam that spreads the one kilometer width of the river. It is run by the New York Power Authority (NYPA) on the U.S. side and Ontario Power Generation (OPG) on the Canadian side. Each side produces enough power for hundreds of thousands of homes.
But once a dam is installed, it can reduce the available habitat for the eels, cutting them off from their natural migration. In some cases, the eels are reported to crawl out of the water and across rocks in their attempts to continue their migration upstream.
“We're lucky here, in the sense that starting in the 70s, eels got access to that upstream habitat once again,” said Perron, referring to the eel ladders that were eventually installed at multiple dams over time.
The eel ladders are a kind of internal ramp that eels can use to climb over the dam, for their upstream migration. It allows them to travel the distance of the St. Lawrence River and access Lake Ontario. To start the journey, the eels must locate a ladder, which is about the width of a sidewalk. There’s just one on either side of the kilometer long dam. They are attracted by flowing water, so small outflows have been installed to help direct the eels. Considerable research has been done to try to help the eels locate the ladders. Once they begin the climb, the journey up can take hours. Not all the eels will make it. But it provides a route option for the first leg of their migration.
Before the population crash, an average of 20,000 eels per day were recorded going through the eel ladder during their peak migration. But the ladder only works one way. Once the mature eels are ready to spawn, to go back out to sea as adults, they have to make it back downstream. And for the second migration, their route has only one option: through the dam turbines.
Perron explained that it takes luck for the eel to make it through.
“If you think of a propeller that's going extremely fast, they just need to sort of be in that opening at the right time.”
There are differing mortality estimates here, depending on where and when the studies were done. But a commonly used study from the late 90s estimated the mortality at about 40% after passing through both dams. And that study was only counting the ones that died within the first few days. It monitored the dam outflow for 88 hours. But there are nonfatal injuries that eel suffers, which could potentially affect their survival or reproduction later in life.
“Going through the turbines, but they have scrapes or lacerations or vertebrae damage. We don't know if they're making it or not,” said Perron.
One program partially funded by OPG helps a few thousand eels per year get around the dam. Commercial fishers trap the eels and then the fish are trucked around the dammed up river. It’s a small number compared to how many eels used to do this trip, but every eel helps. But it forces another question – is there a way to make turbines safer for the fish to begin with?
“So these fish safe turbines, instead of being a blade, they're more of like a scoop that will help sort of scoop the eels through the turbines to allow downstream passage,” said Perron.
Fish safe turbines currently exist at a similar price point and power efficiency as conventional turbines, according to Natel Energy, a company that designs and supplies them. The biggest cost, as explained by Natel’s cofounder Abe Schneider, is the refurbishment itself — dealing with the site preparation, labor and systems.
In 2024, OPG announced a project to refurbish the Canadian side of the dam to increase electricity production. But no mention is made of the eel in the announcement of the construction. OPG declined to provide comment on fish safe turbines.
Both power companies that run the Moses Saunders dam, NYPA and OPG declined recorded interviews. But NYPA did send a statement that it has been an “active collaborator on a Design Feasibility Study… examining turbine design to aid downstream eel passage.”
Since our tour and interview requests were declined, we visited the OPG dam visitor center to learn more.
There’s a big exhibit hall in the back with a banner that reads INUNDATION DAY. It tells the story of the dam construction, and how, as a necessary part of the dam, the river water levels changed, flooding parts of the populated shoreline.
The placard reads, “The Lost Homeland.” It says, “6,000 hectares of traditional lands were flooded and lost. The values, culture and livelihoods of the Mohawk people of Akwesasne were changed forever. The Mohawk people were given no opportunity to influence the projects or to share in the benefits.”
Abraham Francis grew up in Cornwall. He is an Akwesasronon ecologist.
“My first memory of eel was of like finding them on the shoreline. Dogs loved them, loved to roll in them, and they would just stink.It was a big thing. Every year we would see a lot of eel chopped up and whatever in the river, but now we don't see that anymore,” said Francis.
Part of the reason we came to Cornwall is that it’s located just downstream from the Moses Saunders dam. The dead and dying eels that have been hit by the turbines wash up along the shoreline here.
“We research these issues, we understand the problems, and then we develop, like, approaches to address that. Whether that's policy, whether that's more research, however that looks like. Perhaps it is like a funeral procession. The passenger pigeon used to have, like, ceremony specifically for it. But they went extinct, and now they're a dance and they're a song,” said Francis.
He explained the clan system as a way to organize governance, and for him, as a way to organize around grief and loss.
“And I wonder what that means to us as a people; like we lose a clan species. Are we going to watch the loss of a relative in this way when we have, there's solutions out there.”
“It feels like as Indigenous people we're screaming into the void to be heard and we keep getting ignored,” said Francis.
“And it's like, not even just like me, it's so many of, like, my relatives, like the eel as a relative. It's my family,” said Francis.
Francis is getting his PhD in Environmental Science and Engineering, working on a project about shoreline management.
“And I think that’s really the power and benefit of bringing Indigenous people, Indigenous knowledge into the forefront. We have cultures that emerge directly from these landscapes. We have been caring for them for millennia, and we can teach the people around us how to do that, but we have to be supported,” said Francis.
“If there was a mechanism for them to go up and down the river, then they'll come home and they'll be on those natural movements and we'll have a stronger global population to be able to keep us going in perpetuity,” said Francis.
“I want eel back. I want eel to be here for future generations. That's what I really want. And I think it's possible,” said Francis.
In addition to the science, he and Mary Ann Perron also work to create science outreach projects, meet with community leaders and policymakers to raise awareness of the struggle of the American eels in the St. Lawrence region.
Boat ride with eels
One of the scientists from the River Institute, Matt Windle, offered to take us out on a boat to see the dam and the river for ourselves.
The boat motor was frozen to start. They ran hot water from a tea kettle through it.
And then all we had to do was put on giant orange survival suits. The kind that inflate if you fall in and will keep you alive for an hour.
The river is partially frozen. In addition to survival suits, Windle is wearing ski goggles and I’m wearing a ski mask.
The dam cuts a thick grey line across the blue sky and the glassy river. We see it in the distance for awhile before we get close.
We take the boat down the river, past Cornwall Island and Akwesasne land. Windle took us to the location where the eels typically piled up.
“Lots of eels, injured eels and dying eels and dead eels have been accumulating just on this upward slope here. And we call it the eel pile,” said Windle.
It was early spring, and the eel migration does not start until summer, so we were not expecting to actually see an eel. But we did. Lying on the bottom of the river. Its white belly up and its head flat against the bottom. Moving very slightly by the current but otherwise motionless.
The boat held us, a group of journalists and scientists, as we drifted over the eel. We had been chatting and pointing to things along the river, but at this site, we fell silent. The dead eel was bigger than I had expected, and Windle explained how the eels in this watershed are some of the biggest in North America. We had come here to see eels, and we had found them, but somehow what we found was nothing like I expected.
Out to sea with eels
As they start their migration, the eels basically go through puberty, getting reproductively mature, stopping digestion, growing their eyes huge, and using their fat reserves to make this long journey.
And for us mere humans, we have 214 miles of driving to our final stop. Quebec City. Here we’re meeting with Jean-François Dumont, a biologist and the American eel management coordinator for the Quebec Ministry of Environment and Wildlife.
We stood by the St. Lawrence River, close to Quebec City, where the river is narrow and all of this water has come from upstream, from Lake Ontario and Niagara Falls and beyond to the rest of the Great Lakes. Thousands of cubic meters of water per second rushed past us on its way to the Atlantic Ocean. And somewhere under there, in a few months, would be the mature eels.
Understanding the movements of mature eels is just one of the many things that Dumont is working on with his collaborators across the region.
In one example, they capture the tagged eels in tidal traps in the river, and then scan the tags to note which ones went where. This kind of tracking information is important for understanding eel behavior and natural migratory patterns.
“And actually what is good is that we observe a kind of stability. We are on a flatbed period. We know each year we have plus or minus 175,000 eels that are joining the Sargasso Sea,” said Dumont. The numbers are very low, but they are stable.
Dumont and his team also work on otolith shape and chemistry. He described the otolith as a black box recorder for the fish. It’s a calcified structure in their ear that lays down a daily mineral layer, like a tree ring.
“The chemical component for each layer (is) related to the water, where they're living. So that's why it's a very powerful tool. The otolith can give you a signal about the water where the eel grow. But you cannot have other information about what happened in the Sargasso Sea,” said Dumont. “Eels are mysterious.”
At the end of the interview, Dumont reminded us that not all of the female eels go all the way to Lake Ontario. Some of them stay in the St. Lawrence River, for whatever reason. This is a bit complicated. If an eel stops earlier in the river, she might not get as big or produce as many eggs. But she avoids added dam danger. Because at this point in Quebec City, there are no dams yet. So they have free, safe passage to go out.
The great American eel trip
American eels make an incredible journey twice in their life, moving from open ocean to freshwater and back again. The odds are stacked against them, increasingly so with climate change and other human impacts. But animals that can travel thousands of miles, while basically going through puberty on no snacks at all, can probably do anything. Given the chance. The problem is that they’re currently not getting much of one, and they’re not suffering alone; they’re a symptom of wider environmental issues in North America.
One thing really struck me as we went through this journey. American eels are extremely strange and surprisingly hard to study. Due to research limitations and the lack of consistent data collection over time, the eel facts in this story pretty much all have caveats. We are constantly updating our idea of the eel, and there's still so much we don't know.
American eels have been around for millions of years. The real story starts before humans, maybe even before North America. Because eels are slippery, unbothered by space and time, seeming to exist outside of what we think we know about how oceans, evolution, and even bodies, function.
Edited by Rebecca Williams, Vincent Duffy, Dustin Dwyer and Jodi Westrick. Special thanks to Randi Kest, and Jean-Francois Dumont, Daniel LaBonte, and Stephany Hildebrand for additional photos and footage.
Thank you to the Mohawk Council of Akwesasne.
Support for the production of this podcast was made possible by the Charles Stewart Mott Foundation, as part of its Great Lakes News Collaborative.
Music by Blue Dot Sessions.
Beyond the Shore is a production of Michigan Public. You can find all of our podcasts at michiganpublic.org/podcasts.
