Eels on Wheels

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.