Sections of popular recreational lakes a short drive from Thunder Bay are continuing this summer to become partially covered by an unsightly green slime that can be toxic to humans and fish.
Recent samples taken from two lakes near the city have confirmed the presence of blue-green algae, public health officials said.
The Thunder Bay District Health Unit advises cottagers to avoid using the lakes for drinking or recreation until at least two weeks after the blooms have disappeared.
Algae blooms can be toxic and cause health issues. Health experts advise against eating fish that have been caught in the vicinity of blooms, as toxins can accumulate in their organs.
On Friday, a blue-green algae bloom was confirmed for Icarus Lake, which is located about 100 kilometres southeast of Thunder Bay off Highway 588 near Northern Lights Lake.
“There are five cottages on (Icarus Lake), which is also a popular lake for fishing,” the health unit said.
Earlier, on June 30, a similar bloom was spotted on Trout Lake, about 30 kilometres north of Thunder Bay in Gorham-Ware Township.
Trout Lake contains “approximately 125 permanent homes and cottages,” the heath unit noted.
On the water’s surface, blooms often appear like a layer of pea soup, or may have a turquoise sheen.
Some believe this summer could be another bad season for algae, since it often appears when lakes are warm or burdened with high levels of phosphorous from household appliances like clothes and dish washers.
During the hot summer of 2021, the public health unit issued eight warnings for blue-green algae across the Thunder Bay district, the most ever in a single season.
Surprise Lake, another cottagers haven just north of Thunder Bay, has been the subject of three public-health warnings about blue-green algae since 2019. The most recent bulletin occurred last month.
Algae used to be a scourge that mostly afflicted southern Ontario waterways, but has recently been more common in Northern Ontario as temperatures have risen.
According to Ontario’s Ministry of Environment, lakefront property owners can reduce their phosphorous output in a number of ways, including “using phosphate-free detergents, not bathing in lakes, maintaining naturalized shorelines, not using fertilizers . . . and ensuring that septic systems don’t leak or discharge into water bodies.”
