green algae on the lake in summer

Blue-green algae awareness

Our communities are surrounded by beautiful lakes and rivers with easy access for everyone to enjoy. It is important to be aware of the presence and the dangers of blue-green algae when heading out this summer.

Blue-green algae tends to develop when a period of hot, dry weather is followed by a heavy rainfall. It’s becoming more common because of warmer temperatures and more intense storms caused by climate change.

Ways to identifying blue-green algae:

Despite the name, blue-green algae can be turquoise, green, brown, red, white or mixes of these colours. Blue-green algae blooms can look like fine grass clippings in the water, spilled paint or pea soup. Sometimes they look like a thick scum on the surface. They often smell musty or grassy when healthy and like ammonia when decomposing.

There may also be algae mats at the bottom of clear shallow areas of lakes and rivers or on the shoreline. The algae mats look like clumps of vegetation and can appear black, brown, or dark green in the water.

On the shoreline, they may appear brown or grey once they have dried. Animals are attracted to their odour and may try to eat them. Keep children and pets away from algae mats.

Reporting blue-green algae:

If you think you see blue-green algae, you should treat it as potentially toxic. Report it to your local Department of Environment and Climate Change office or call 1-877-936-8476.

The Department of Environment and Climate Change will share through social media reported blue-green algae in public drinking water supplies and popular lakes. This will help people be aware and careful to protect their family and pets. In the case of public drinking water supplies, an inspector will visually confirm the presence of blue-green algae and work directly with the water supply owner.

Once blue-green algae appears, it’s more likely to reappear in the same body of water.

Learn more about blue-green algae safety and how it effects drinking water sources here: