Diavik says more testing needed before stocking fish in Yellowknife’s Frame Lake
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Company previously said fish might be brought in this summer
Yet another year has gone by without any fish in Yellowknife’s notoriously polluted Frame Lake.
Diavik Diamond Mine and its owner Rio Tinto have been trying to restore the lake for several years to make it suitable for fish. In 2024, the companies installed a deep-water aerator at the north end of the lake to increase oxygen levels during winter months.
A Diavik spokesperson confirmed in a statement to CBC News last month that no fish would be reintroduced to Frame Lake this year as water monitoring continues. The company had previously said it would maybe bring in fish this summer.
Pike, ninespine stickleback, walleye and lake chub are among the species being considered to be reintroduced into the lake.
More sampling is to take place this winter and Diavik says it will only move forward with stocking Frame Lake if testing shows it can sustain fish life.
Why are they trying to put fish in the lake?
The federal Fisheries Act requires the company to offset the destruction of fish habitat at the Diavik mine in Lac de Gras, some 300 kilometers northeast of Yellowknife.
“[As] part of the Fisheries Act authorization you need to counterbalance the impacts you have on fish and fish habitat. So for example you can restore, you can enhance fish habitat, you can remediate an area that is polluted, and then you can create new habitat,” said Tatiana Leclerc-Beaulieu, a senior biologist at Fisheries and Oceans Canada.
“You still have to monitor it. You have to make sure that your offset project works.”
Leclerc-Beaulieu added that Diavik may have to try restoring fish habitat elsewhere if its Frame Lake efforts don’t pan out.
What’s wrong with Frame Lake?
The lake in the heart of the Northwest Territories’ capital has been considered “dead” for decades, meaning conditions are inhospitable for aquatic creatures.
Decades of urban runoff and the disruption of natural water inflows and outflows led to a buildup of nutrient-rich sediment in the lake. This fed plant life which draws oxygen levels in the lake down to zero when it freezes over in the winter, making it impossible for fish to survive.
The lake also contains high levels of arsenic pollution from historic gold mining operations in Yellowknife. This pollution poses yet another threat to fish. Humans and their pets are also advised to stay out of the water.
MLA welcomes effort
Julian Morse is the MLA for the Frame Lake riding.
A born and raised Yellowknifer, he says he’s excited at the prospect of fish being brought back but is not surprised to hear there has been a delay.
“[It’s] disappointing to hear that they haven’t been able to move as quickly as they may have expected, but that’s science. I didn’t expect that this was going to be an easy project for them. I’d be curious to monitor how it goes,” Morse said.
Related stories from around the North:
Canada: Federal committee hears Yukon River salmon are imperiled, CBC News
Sweden: Dead salmon in northern Sweden are worrying researchers and fishermen, Radio Sweden
United States: Alaska Natives welcome new state limits to protect chum salmon, CBC News
