Eels on Wheels
The curious conservation of the Great Lakes eel
Peter Hodson was eleven years old the first time he saw an eel, on June 27, 1959. He also saw the Queen that day, a white speck in the distance, as she unveiled the International Friendship Monument, which stands at the precise point where the R. H. Saunders dam, operated by OPG (then Ontario Hydro), meets the New York Power Authority’s Robert Moses dam. The unveiling was in effect a delayed ribbon cutting for the joint hydroelectric complex, which had been in operation for a year. Virtually all the fresh water in the Great Lakes basin, barring leaks through a few ship canals, pours through its thirty-two turbines — nine million litres a second, generating 2,090 megawatts of power. More clearly than he remembers the Queen, Hodson recalls the eels, hundreds of them, their dead, broken bodies floating on the surface downstream.
The construction of the Moses-Saunders complex, which supplies about 4 percent of Ontario’s energy requirements, had required the flooding of 8,000 hectares of the province’s shoreline and the relocation of ten communities. Among those displaced were many Akwesasne Mohawks, who moved down stream to a reservation on Cornwall Island. In the seventeenth century, a Jesuit missionary wrote that an aboriginal, hunting eels by torchlight during their annual migration down the St. Lawrence, could spear a thousand a night.
Eels were a mainstay of native life: the skins, which tighten when dried, were used to bandage wounds, relieve rheumatism, and wrap tool handles; the fats were used to water proof clothing; the oils, to cure earaches. Most important, the meat was highly nutritious and portable. But after the dam was built, the silvers’ annual downstream migration precipitated a new summer ritual: in July and August, the band council sent out trucks and wagons to collect dead and rotting eels along the shore. Henry Lickers, the council’s environmental director, says the bodies accumulated half a metre deep in coves and bays downstream from the dam. “It was horrible to see,” says Lickers.
“It was the wholesale destruction of a species. We complained about it, but no one would hear us. Eels are not seal pups, and in those days there was no ‘environment.’ ”
The immediate mortality rate for the large eels that ran the Moses-Saunders gauntlet was 26.4 percent. Of the survivors, another 24 percent died later at the Beauharnois dam. The two-and-a-half-metre blades at Moses-Saunders spin at a rate of 95 rpm, so fish, particularly long ones, are inevitably struck, if not sliced, by them. Moreover, turbine shafts are designed to pressurize the water hitting the turbines, and the rapid change affects the fish’s swim bladder, the internal organ that helps it maintain buoyancy. So many more eels probably died farther downstream. The slaughter wasn’t exactly a surprise; some commercial fishermen welcomed it as a solution to the “eel nuisance.” Eels look like snakes; they’re slimy, hard to handle, and tough to kill. Since they have small mouths and small, dull teeth, they extract bite-sized morsels from large carcasses by clamping on, spinning on their axis, and hitting reverse; if the carcass happens to be attached to a gillnet or a longline, too bad for the gear.
But a funny thing happened after the dam was built. Domestic and European markets for eel expanded. As the price went up, so did the harvest, which disturbed MNR fisheries managers, who knew that with the dam in place the resource was no longer renewable. Every summer, millions of elvers, twelve to fifty centimetres long, piled up at the foot of Moses-Saunders, particularly on the Canadian side. This created serious problems for Ontario Hydro, which regularly interrupted the flow of water into its turbines, and then dropped stop logs into the tailrace leading out of them so the turbine wells could be pumped dry for maintenance. But before the stop logs could fall, elvers looking for passage upstream would dart into the well and be sucked into the dewatering pumps and jam them.
“I don’t know if you’ve ever seen chopped eel, but it starts to rot about ten seconds after it goes through the chopper,” says Robert Scally, a former mechanical maintenance superintendent with Ontario Hydro. “All you could do to clean it out is start dismantling things, but that was difficult, because a lot of this piping is embedded in concrete. It was like the whole system was full of hamburger, and it took days to scoop it out.”
In the early 1970s, the late Russ Whitfield, a biologist with the MNR, promoted the idea of building an eel ladder that would keep the eels out of the pumps and moving upstream. The proposal was undoubtedly based in pragmatism, but the rationale Whitfield gave a reporter then sounds much more sentimental. “They wanted to migrate so badly,” he said, “but the dam was in the way.”
Eels are endearing in their weirdness. Until recently, they were considered exclusively catadromous, meaning they are born, spawn, and die at sea but spend their lives in fresh water; salmon do it the other way around. Eels are also considered panmictic, in that they do not pair off but spawn in a mass commingling of eels, eggs, and sperm in the Sargasso. The consequence of panmictic catadromy is that there is no selection of mates, and therefore no genetic divergence induced by local conditions, and no homing instinct to a particular freshwater habitat. Currents carry the larvae to the coastal waters of Venezuela, Central America, Mexico, the American Gulf and Atlantic states, the Maritimes, Newfoundland and Labrador, and Iceland. By the time they reach Canadian waters, they are about a year old and are beginning to morph, first into glass eels, which look like swimming vertebrae, and then into tiny yellow eels.
Apparently driven upstream by population pressure, like cottagers, the elvers will leave the water if they must, to slither through cracks in rocks, or up damp vertical walls, or even across wet lawns and meadows. They can entwine themselves into a living rope as long as three metres, to overcome obstructions. The eels that manage the journey upstream and live at low density tend to become female; the losers that stay behind, in the crowded lower reaches of rivers or in saline estuaries, predominantly become male. Eels are eaten by just about everything in the saltwater food chain, and by the time they attain the pinnacle they have returned the favour, as both predators and scavengers. When the St. Lawrence Seaway opened, it was not immediately recognized that inbound freighters were bringing with them a horde of invasive species; the still-abundant population of eels undoubtedly consumed many of these pests before they took hold. So there were good reasons to help them reach the lake.
No one had ever built an eel ladder to surmount an obstacle thirty metres high. The one thing Whitfield had going for him was that the dam was intersected by ice sluices, twenty-one metres wide and ascending at a seventy-degree angle. These spillways, contained within the dam, were intended to allow upstream ice jams to slide into a downstream inlet. In practice, the ice was never that bad, so this had never happened. Whitfield settled on a design for a wooden trough that zigzagged back and forth up the face of one of the sluices. To test the idea, he installed a single length of the trough with its bottom in the bay and pumped water down it. The elvers were drawn to the current, but none would enter. Whitfield must have figured out that while salmon jump upstream, eels climb. He wired short willow cuttings along the length of the ladder and happily reported that the eels packed in and, a day later, began rolling off the upper end in a steady stream.
The full ladder was installed in 1974 and was an immediate success; more than 4.3 million young eels ascended over the next six years. In 1981, Ontario Hydro replaced the wooden structure with a more permanent aluminum ladder. Another 2.6 million eels moved through in 1983 and 1984. The MNR dutifully kept track of the numbers and posted them in an internal fisheries report. “When you spend all that money on a ladder, you want to know that it’s working,” explains Mike Eckersley, the MNR biologist in charge of the ladder at the time. “But after a few years, we realized that we had the most extensive and most reliable index of eel recruitment in the world.”
One of the interested biologists who followed the annual eel census was Peter Hodson, by this time a toxicologist at the Maurice Lamontagne Institute, a marine research centre operated by the federal Department of Fisheries and Oceans near Mont-Joli, Quebec. He was studying beluga whales in the Lower St. Lawrence River and the Gulf of St. Lawrence, whose body fat carried an astonishingly high level of chemical contaminants, hypothetically because they were feeding heavily on the silvers coming out of Lake Ontario. (Hodson admits that he would have preferred to study eels directly, but in Ontario and Quebec they are considered a freshwater fish and fall under provincial rather than federal management; in the Maritimes, they are a marine fish, so their harvest is supervised by the DFO.)
However, the days of eels as an abundant, albeit obscure, species were about to end. The count was still high in 1985, when 935,320 juvenile eels ascended the ladder, but over the next four years, like a sputtering investment, it began to fall, hitting 258,622 in 1989. Then it crashed: 121,907 in 1990, 40,241 in 1991, and 11,534 in 1992.
“We were quite upset,” says Hodson. “It looked like a catastrophe. It wasn’t just that 1992 was a bad year; it was the overall trend. We were seeing a 99 percent decline, which is exponential, and there was no sign it was going to let up.”
Hodson was already slated to present a paper on contaminants in eels at a 1992 conference of the International Council for the Exploration of the Sea in Poland, convened as the stock of European elvers was crashing. Needless to say, the relationship of European and American eels is complex. The two species derive from the same ancestor but are genetically distinct, so they have somehow avoided each other’s annual party in the Sargasso. At the conference, Christopher Moriarty, an Irish researcher, put up a graph showing the decline of elver harvests in European rivers from 1980 to 1992. The shape of Moriarty’s diagram, Hodson realized, was virtually identical to the graph he had made of the Saunders numbers. The only difference was that the European crash preceded the collapse at Saunders by four years. And that was easily explained by the fact that the dam is 1,600 kilometres from the ocean — a four-to-seven-year swim for an eel.
Back in Canada, Hodson worked with biologist Martin Castonguay and pathologist Catherine Couillard, also of the Lamontagne Institute, on the first peer-reviewed paper to report the collapse of the juvenile American eel in the St. Lawrence River. The data from the Moses-Saunders dam was supported by eel surveys showing sharp drops at Quebec rivers feeding into the St. Lawrence. The article examined four possible causes for the decline: pollution in Lake Ontario, construction of the dam and the St. Lawrence Seaway, overfishing, and a weaker Gulf Stream. Lake Ontario was grossly contaminated, but it had been much worse in the 1960s, so if chemicals were to blame the effect should have shown up sooner.
Moses-Saunders and the seaway destroyed the habitats of many fish when they were constructed in the 1950s, but again the time lag was too great to explain the current decline. Quebec fishermen were continuing to take silver eels out of the St. Lawrence, and since 1975 had captured about 400 tonnes a year, but the comparative stability of that harvest ruled it out. Finally, it seemed possible the Gulf Stream had weakened, but this had happened in the early 1970s with no notable reduction in eels at the ladder. “By and large,” their paper concluded, “we do not really know what caused the pronounced recruitment decline in this species.”
In August 2003, eel experts on a field trip from an international symposium in Quebec City compared notes on the dramatic drop in juvenile populations among the Atlantic and Pacific branches of the Anguillidae family of eels. Among the scientists were MNR biologist John Casselman and David Cairns, a DFO fisheries manager from Prince Edward Island. “We sat there,” Casselman recalls, “saying we really need to do something here and this is the chance to do it.”
The upshot was the Quebec Declaration of Concern, endorsed by virtually all the symposium delegates from eighteen countries. Its wording, subsequently worked out in telephone calls and emails, departed sharply from the usual calm detachment of scientific papers: “With less than 1 percent of juvenile resources remaining for major populations, time is running out. Precautionary action (e.g., curtailing exploitation, safeguarding migration routes and wetlands, improving access to lost habitats) can and must be taken immediately by all parties involved and, if necessary, independently of each other.”
Meanwhile, back at the eel ladder the numbers had improved slightly: after hitting an all-time low of 944 in 2001, they were up to 2,876 in 2003. The MNR had twice cut fishing quotas for yellows by 50 percent — not that this was a problem for fishermen, since the actual catch was even lower. Rob MacGregor, the manager in charge of the Lake Ontario fishery, wrote a briefing note recommending the complete elimination of the eel quota. He explained the crisis and dutifully pointed out that given the panmictic, catadromous nature of eels, closing the Lake Ontario eel fishery would not necessarily bring them back. Since population pressure drives eels upstream, the collapse in Lake Ontario, at the extremity of the range, was a strong indicator that the entire species was in decline, notwithstanding the fact that harvests in the Maritimes remained high. Conversely, MacGregor and others thought, even if the species as a whole was not threatened, the past abundance of the Lake Ontario cohort, and its known fecundity, meant it soon would be. The zero quota took effect in the spring of 2004.
“Eels are harvested in twenty-five jurisdictions, at every stage, from glass eels to silver eels,” says MacGregor. “But it’s all one population, and they only spawn once, so everything adds up. Each agency has been doing its own thing, but nobody has looked at the overall population level. On the East Coast, they look upstream and say, ‘You’ve got all these mortalities with dams, so why are you putting all this on our back?’ Or jurisdictions look at their own data and say, ‘Our eels are fine.’ So there were all kinds of reasons to say, ‘Well, if all the other jurisdictions aren’t doing anything, why should we?’ But we weren’t going to sell the last eel out of Lake Ontario.”
The eel debate has been conducted quietly among civil servants, mostly below the radar of the media or environmental activists. In true civil service fashion, problems and differences have been tackled in the decorum of working groups, particularly the Canadian Eel Science Working Group, which is seeking a scientific consensus on the state of the species; and the Canadian Eel Working Group, whose subcommittees are dedicated to pursuing interprovincial and international accords relating to eels, and resolving the still-unanswered question of why eels in Lake Ontario have declined so drastically when they seem abundant elsewhere. A challenge for both groups is that central Canada’s provincial resource ministries and the DFO, which manages the East Coast fishery, have dramatically different views of the eels. This became starkly apparent in 2006 at hearings of the Committee on the Status of Endangered Wildlife in Canada. After reviewing a report submitted by the science working group, COSEWIC agreed to recommend to the federal environment minister that the eel be listed as threatened, which would entitle it to a host of rigorous protective measures. But later in the four-day meeting, the issue was reopened, and COSEWIC downgraded its status recommendation to “special concern.”
Present at that meeting was David Cairns, who had co-authored the Quebec Declaration, and served as co-chairman of the science subcommittee that submitted a report on the decline of the eel to COSEWIC. Cairns no longer believes the eels are endangered. “The idea that the collapse in Lake Ontario in the 1980s and 1990s is a harbinger of bad things to come for the species as a whole is hard to accept in the Maritime provinces,” he said, “because since then eel abundance here has doubled or tripled.”
Cairns fielded questions at the COSEWIC hearing, many of them about research, ongoing since 2003, by Heather Lamson, then a master’s student at the University of New Brunswick working under his supervision. Lamson had analyzed otoliths, the ear stones created by calcium deposits, in PEI eels captured in freshwater ponds, in brackish waters at river mouths, and in saltwater bays. By chemically analyzing the otoliths, she found that many eels moved freely among the three environments. More particularly, she showed that 85 percent of the thirty-nine saltwater eels in the study had lived in salt water all their lives. By implication, the existence of eels thriving in a marine environment, safe from both fishermen and hydroelectric dams, might mean that saltwater habitat is more important for the species than previously understood.
Cairns presented the same, still-unpublished, data to the US Fish and Wildlife Service, which also considered listing the eel as endangered but ultimately decided against it. MacGregor, among other Ontario biologists, is not convinced that the new study changes anything; no one knows the significance of the marine cohort, its fecundity, or the ratio of males to females. “If you’re satisfied with losing eels in fresh water, if your only objective is to keep them from going extinct, that’s one thing,” he says. “But if you want eels to perform their ecological, cultural, and economic functions in fresh water, that’s another.”
In the meantime, the CEWG subcommittee working on international accords has produced a memo of understanding to coordinate sustainable management, likely to be signed this year by Ottawa, Quebec, Ontario, the binational Great Lakes Fishery Commission, and the Atlantic States Marine Fisheries Commission, which represents the fifteen states of the Eastern seaboard. In Ontario, eels have been listed as endangered, while a national management plan to affect a 50 percent reduction in anthropogenic mortality is undergoing “final tweaking.”
A committee investigating the impact of dams has taken a hard look at the Ottawa River; another brokered the agreement by which OPG will truck yellow eels to Lac Saint-Pierre until at least 2011. Silvers would have been better, but they are virtually impossible to capture in the lake’s open water. As it is, there are so few eels left in Lake Ontario that most of the 1,300 yellows captured this past summer came from the St. Lawrence River, downstream from Moses-Saunders. This summer marked the third year in a row that OPG trucked young glass eels in the other direction, releasing them near Mallorytown and Deseronto. To the relief of everyone involved in the project, biologists also captured yellow eels in Lake Ontario that had arrived by truck two years earlier.
My stated job on the little fishing boat was to stay out of the way, while OPG biologists concentrated on dumping nearly 700,000 elvers out of plastic bags and into Lake Ontario. The elvers were tiny, 7,000 swarming in each of the bags piled in corners of the deck. Someone with exceptionally strong wrists, perhaps a fisherman, had tied the bags shut the day before in New Brunswick, so I volunteered to open them. Since no one complained, I also collected the empties. Some of these, I noticed, still contained stragglers, bravely climbing the plastic or swimming vertically against trickles of water.
I don’t care what you think about eels; you have to admire a critter less than five centimetres long that travels 6,000 kilometres from the Sargasso to New Brunswick, and then to Lake Ontario, even if it did finish the trip as a hitchhiker. The idea of letting any of them die here, on the doorstep to eel paradise, was unbearable. So I flapped the bags overboard, as unobtrusively as possible, until they fell out. Then I noticed that some had missed the transfer from bag to bucket to lake and were swimming and slithering between our rubber boots on the deck. I got down on my hands and knees to rescue them, too. This was a clear violation of my job description, so I tried to do it quickly. But catching them was like picking up wet hair from a bathroom floor, except they wiggled.
OPG had never been noticeably warm to my inquiries about eels, or to my demands to take part in this last release of the summer. I half-expected Ron Threader, the biologist in charge, to tell me that I was literally getting under foot. He might also have reasonably observed that with the completion of the day’s work, OPG would have introduced two million elvers to the lake and river, against which a few eels in the bottom of the boat were insignificant. Instead, he knelt beside me.
“You need to catch them under your fingernail,” he said.
He expertly caught one and flicked it overboard. We stayed there until we got them all. So it was a good day for eels, even the stragglers — and, not incidentally, a good day for Lake Ontario.