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Testing sediment and fish for methyl mercury, scientists help an Anishinaabe nation examine the legacy of hydro development in the 20th century

Pulling at a rope submerged below the mysterious depths of northwestern Ontario’s Lake Nipigon, research scientists are trying to free a coring device that’s suctioned into the lake bottom.

With a group effort, the line goes slack and slowly is reeled in until Joshua Thienpont, a specialist in paleolimnology at York University, reaches down to cap the bottom of the sedimentary core sample before the layers spill back into the water. A round of cheers goes up as the sample is hoisted aboard the Velma Linda, a 49-foot research vessel owned by the Biinjitiwaabik Zaaging Anishinaabek (BZA) Lake Nipigon Guardians Program.

“That’s a lot of history, that’s the story of our people,” said captain Abraham Kowtiash, who was born and raised on a tugboat by his family of commercial fishers. No one knows Lake Nipigon’s uncharted waters better than him.

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Abraham Kowtiash, middle front, smiles as researchers Joshua Thienpont and Robert Stewart handle a sedimentary core sample from Wabinosh Bay.

Along with his son, Adam, and two other community members from their First Nation, BZA, he’s helping steer scientists from York and Lakehead universities to the places his community wants to know more about and to do research that sets a baseline health of the lake.

Sedimentary core samples such as the one just brought aboard are tangible evidence of the devastation Lake Nipigon survived 70 years earlier after hydroelectric diversion dams were built, leading to concerns about methyl mercury in the abundant fish population.

As the Velma Linda chugs along with seven onboard, a setting sun sets the tug ablaze while Brendon Hardy, lead monitor for the Guardians program, tosses a walleye carcass to trailing seagulls.

He is working alongside Tim Hollinger, co-ordinator for the Lake Superior Remedial Action Plan, and the two are cataloguing each fish caught earlier in the day for species, length and weight before removing small squares from the fishes’ backs.

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This sample from a brook trout will be tested for methyl mercury at Lakehead University.

Robert Stewart, a professor in the Department of Geography and the Environment at Lakehead University, takes the small sample, wraps it in tinfoil, places it inside a clear, numbered bag and winds it shut before placing it with the other samples in a cooler.

Mr. Hardy, the son of a commercial fisher, grew up on Lake Nipigon, and he’s eaten the fish, like everyone else from BZA, all his life. Now, these samples will provide real numbers about methyl mercury in the fish.

Along with core samples from the sediments, the Guardians program – which provides federal funding to support Indigenous stewardship over land, water and ice – is gathering data on Lake Nipigon to illustrate what, until lately, has only ever been oral history.

On a sunny summer day, Adam Kowtiash and the researchers consult a map of the lake and Brendon Hardy, lead monitor of the Guardians program, sets a net for walleye. Their findings could give BZA members a clearer idea of how Nipigon was transformed by hydro development in the 20th century.
Dr. Stewart inspects a spiny water flea recovered from the lake. Brought to North America by ocean liners from Europe and Asia, the invasive species can starve fish to death by clogging their throats.
Nipigon can stay quite cold all summer long, but bays and river mouths are fine for swimming on hot days. Dr. Stewart, leaping from the Velma Linda, is about to find out what the water is like today.

In the 1950s, the Army Corps of Engineers, in an effort to raise the hydroelectric potential of the Great Lakes, built two diversion dams that would transport water from the north flowing Ogoki River watershed into Lake Superior.

They constructed the Little Jackfish River into Lake Nipigon’s north end, built the enormous Waboose and Summit Control dams, and began pumping arctic water into the Great Lakes Basin.

In a matter of days, Lake Nipigon went milky white from an influx of sediments, homes of local First Nations were flooded, graves went underwater and no one had been warned.

For years, bluffs eroded from high water levels, and while the sediments eventually settled, the veil of mystery has never been lifted.

All that remained were questions: How much did Lake Nipigon rise in the flooding? What volume of sediments was pumped into the pristine lake? How much did the methyl mercury content in fish rise as a result of a flooded forest reservoir above the diversion dams? Most importantly, to the local First Nations, why have they never been advised on the health of their lake?

Before the Guardians program, these questions went unanswered. Despite years of research on the lake, the Ontario Ministry of Natural Resources has never created a management plan for Lake Nipigon, nor have they made available any of their findings to the people who spend their life on the lake.

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A sedimentary core, sliced into thin discs and sorted into plastic bags, can record centuries of activity on the lake bed.

A good sedimentary core sample can date back hundreds of years, sometimes more, to a time before the local Ojibwe, the ancestors of Mr. Kowtiash and Mr. Hardy, had contact with European fur traders. Like chapters in a book, the sediments slowly reveal the story of an ancient lake, from sea shells to petrified wood, until a sudden change begins to form, then rapidly accumulate.

Tying the bind between traditional knowledge and scientific discovery, the arctic sediments resting atop Lake Nipigon’s bottom layer are evidence of what time and industry have tried to hide.

In a maze of islands, the Velma Linda is moored to an island similar in size to the tug, one of many safe harbours that Mr. Kowtiash can navigate to without a GPS or depth chart. On shore, with quiet drumming playing from his phone, Mr. Hardy holds a ceremony to thank the lake and creator. He’s offered food, tobacco and cedar, followed by burned sweetgrass and sage.

“I want my children to enjoy this lake all their life,” he said. “I want them to eat the fish, to enjoy this beautiful water. That’s why I’m a guardian, to protect Lake Nipigon.”

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