Atlantic salmon once dominated the depths of Lake Ontario, so plentiful, a person could bend down and scoop the huge fish out of the water. But the last of the salmon was caught more than a century ago. Enter genetic researcher Oliver Haddrath, who is determined to restore this top predatory species to the lake and reverse the course of history

by Sharon Oosthoek

Oliver Haddrath stretches out his hand, palm up. He is holding what little remains of an ancient predator that once dominated the waters of Lake Ontario. Seated in a tiny, well-ordered office on the third floor of Toronto’s Royal Ontario Museum (ROM), surrounded by flow charts showing the genetic links between long-dead creatures, the scientist’s attention is focused on the thumbnail-sized object resting in his hand. Despite his six-foot-one frame and broad shoulders, Haddrath has the air of a child trying to contain his excitement. He gazes at the yellowed, pockmarked vertebra sealed in a plastic bag. “Six-hundred-year-old fish bone,” he says, striving unsuccessfully for an even tone.

Haddrath places the vertebra in a small cardboard box atop two fistfuls of Atlantic salmon bones that also date back to the 15th century. The bones are among the last relics of physical evidence that Lake Ontario was once home to these huge freshwater fish, a species that could weigh as much as 20 kilograms – more than any other freshwater salmon in North America.

A decade ago, the bones were still buried in rubbish heaps at the sites of two Iroquoian villages that, several hundred years ago, flourished on the north side of the lake. One village now lies beneath an Oshawa suburb, the other under a suburb near Vaughan. Haddrath, a research technician in the ornithology division at the ROM , is on a mission to use the bones to restore the fish to its former place at the top of the Lake Ontario food chain. Atlantic salmon were once so plentiful that people caught them with pitchforks, before their decline sparked fierce competition between local First Nations and white settlers.

“From a historical point of view, we’d be thrilled if we could get back the original population,” says Haddrath, abandoning any attempt at dispassion. “That would be the coolest.”

Although a highly regarded expert in decoding ancient DNA, Haddrath has never before attempted to bring back a locally extinct species. He made his name by mapping the mitochondrial DNA genome sequences of several species of large flightless birds – including the moa of New Zealand, a bird that has been extinct for nearly five centuries. As a graduate student at the University of Toronto, Haddrath showed how the birds are related to one another and how continental drift shaped their distribution over the last 80 million years. He continues to study and develop new molecular markers that may reveal the earliest evolutionary events surrounding the origin of birds.

The big fish

Salmon weights vary widely, depending on how much time the fish spends fattening up in the ocean or a large lake with a good food supply. Non-ocean-going Atlantic salmon in Maine, for example, once tipped the scales at nine kilograms, but today’s diminished food supply means they now average just under an unimpressive two kilograms. Stocked Atlantic salmon in Lake Ontario can weigh up to almost 11 kilograms.

Atlantic salmon that feed in the ocean for at least two years can reach about 11 kilograms, but those that stay at sea an extra year can double that weight. Among the three species of Pacific salmon stocked in the Great Lakes – none of which go to sea – pinks are the smallest, at almost three kilograms. Coho can reach just over 13 kilograms, while chinook have been caught that weigh more than 18 kilograms.

Sharon Oosthoek

It is Haddrath, who oversees one of two molecular genetic research labs at the ROM, to whom other scientists turn when trying to unravel the mysteries of the past. At the behest of a local biologist, Haddrath once extracted DNA from sediment at the bottom of Crawford Lake in Milton, identifying the sample as 600-year-old Canada goose droppings. The biologist wanted to prove that 15th-century Iroquois practiced agriculture in the area by showing that geese fed on the crops and defecated over the nearby lake. “That’s the dirtiest thing I’ve had to do,” says Haddrath, “get DNA from poop.”

For almost three years, Haddrath has focused his considerable energy on residual slivers of Atlantic salmon DNA in the hopes of identifying unique genetic markers in the vertebrae that can be matched to isolated populations of Atlantic salmon outside the province. Historical records show that sometime before the last fish was caught off Scarborough Beach in 1898, Atlantic salmon eggs from Lake Ontario were transported to Quebec, Maine, Pennsylvania, New York, New Hampshire, Rhode Island, Utah and Iowa to restock declining salmon populations there.