Blue-green Algae

There are currently no Blue-green Algae advisories for Alberta Lakes.

Blue-green advisories may be found on the Alberta Health Services Website at:

What is blue-green algae?

Blue-green algae are actually common, naturally occurring bacteria, known as cyanobacteria.

From early June to mid-September, when the days are sunny and hot, cyanobacteria may accumulate to the point that a bloom is visible at many of Alberta's nutrient-rich lakes.

Is blue-green-algae a threat to my health?

Some bloom-forming cyanobacteria can produce toxins that, if contacted, may cause skin and eye irritation, or, can result in intestinal discomfort or severe illness in humans if ingested.

Consumption of sufficient quantities of cyanobacterial toxins can lead to death in livestock, pets or wildlife.

When blue-green algal blooms decompose they can cause a sewage-like odour that may be offensive to recreational users.

Can blue-green algae affect fish?

Fish are exposed to toxins from cyanobacteria during feeding or through the gills during breathing. Toxins in the water may cause damage to the liver or nervous system of fish that rarely results in death. Fish can survive much higher levels of toxins from cyanobacteria than mammals can.

Rapid decomposition can also deplete the water of oxygen and produce high levels of ammonia, which can kill fish and other aquatic animals.

The hot weather that contributes to blue-green algae blooms also depletes water oxygen levels and cause fish die-offs.

Should I eat fish caught from a lake with blue-green algae?

Toxins from cyanobacteria have been shown to accumulate in the liver of exposed fish. Small amounts have also been shown to accumulate in kidneys, blood, gill, bile, intestines and brain. It is recommended that people limit their consumption of fish organs, including the skin.

Prevent your pets from eating fish caught from a lake with blue-green algae.

Studies in Alberta indicate that toxins from cyanobacteria are unlikely to accumulate in the flesh of fish at levels high enough to be hazardous to humans. Correctly gutted or filleted fish represent minimal to no health hazard to human consumption.

Is the Government of Alberta monitoring Alberta lakes?

A number of government ministries are working together to keep Albertans informed. Alberta Health Services monitors approximately 40 public recreational sites on 30 lakes, based on the popularity of the recreational site and water quality indicators.

Alberta Environment and Parks is monitoring 50 - 60 whole lake sites, including many of the lakes being monitored by Alberta Health Services.

Whole lake monitoring involves collecting and analyzing samples that represent the average quality of the whole lake rather than sampling that only represents the water quality of a limited are such as the shoreline of a beach.

How will I know if there's a blue-green algal bloom in a lake?

Lakes with blue-green algal blooms will undergo visible changes - otherwise clear, transparent water may suddenly become soupy in appearance, often turquoise, bright blue, gray, tan or even red in color.

This summer, permanent public information signs will remain in place at beaches at the following major recreational lakes that experience intense cyanobacterial blooms and have been placed under public health advisory during each of the last two years:

  • Calgary Zone:
    • Eagle Lake
    • Severn Creek Reservoir
    • Twin Valley Reservoir
  • Central/Edmonton Zone:
    • Pine Lake (just in Central Zone)
    • Pigeon Lake
    • Hastings Lake (just in Edmonton Zone)
  • North Zone:
    • Baptiste Lake
    • Calling Lake
    • Cross Lake
    • Lac La Biche
    • Lake Isle (also in Edmonton Zone)
    • Long Lake
    • Moonshine Lake
    • Muriel Lake
    • Kehewin Lake
    • Lac La Nonne
    • Lac St. Anne
    • Shiningbank Lake
    • Thunder Lake
    • Vincent Lake

Permanent information signs describe how to identify a bloom, public health concerns associated with blooms and information about how beach users can protect their heath.

What should I do if there is a blue-green algal bloom advisory for a lake?

  • Treat any algae bloom with caution
  • Do not drink from bloom-infested lakes and reservoirs. Do not drink any untreated surface waters. Boiling water will not reduce the risk.
  • Do not swim or wade, or allow your pets to swim or wade, in any areas where blue-green algal blooms are visible. Areas of the lake where a bloom in not visible can still be used for recreational purposed, even while an advisory is in place.
  • Provide alternate sources of drinking water for domestic animals and pets

Additional information on cyanobacteria/blue-green algae:

Get up-to-date health advisories:

Updated: Feb 23, 2017