“The Don River in Toronto was once so polluted with waste, garbage and chemicals that it caught on fire. The water itself, which flows towards Lake Ontario, was so inhospitable that it hosted life’s very antithesis.

Now, after huge efforts to renaturalize the area, researchers are seeing a rebirth. The river has gone from being pronounced dead in 1969 to a place that is attracting fish and other aquatic species.

This month, Toronto and Region Conservation Authority (TRCA) shared its findings from the Don River in 2025, which include more than 20 fish species documented in its waters. For the first time since 2012, an Atlantic Salmon was found in the area, along with the first-ever Emerald Bowfin — a warm-water fish native to Ontario — upstream of Lake Shore Boulevard in the Don River watershed.”

From National Observer.