Issue report


Ontario, Canada

Reported by:
Doreen Watson-Donald

About this Location

Mississippi Lake : Mississippi Lake

12 Observations
1 Issues


The area has a very large mat of dense green algae covering most of the bay. the algae was discovered about one week ago and has grown exponentially since that time. the algae has a texture very much like horse hair and retains its texture when taken from the water. under the water the algae is very wispy and has long strands that twine together. it appears to be a filamentous algae like pithophora, but am not sure.


Have you seen this before?

Have not seen this algae on the lake before, but the same day as I gathered the samples of this algae, I also saw several mats of this algae floating in the Big Lake section of Mississippi Lake

Have you notified any other agencies?

I have notified the Mississippi Valley Conservation Authority and am taking samples in to them for identification


Current weather What's this?
  • sunny
Very hot weather
Weather in previous 24 hours What's this?
Very hot weather for about a week.

Issue history

  • 2020-06-19 - 15:26:00

    Algae reported to Water Rangers : Guardians by Doreen Watson-Donald.

  • 2020-06-24 - 12:08:00

    Doreen Watson-Donald has closed this issue.

    Images were sent to Mississippi Valley Conservation Authority for identification. It is filamentous algae, likely of the Spirogyra group. While these types of green algae do not produce toxins as per Cyanobacteria, the mats can affect aesthetics and degrade habitat. A water test was conducted in the bay yesterday: pH 8.0 secchi depth 1.0 hardness 50.0 dissolved oxygen 8.0 chlorine 1.0 alkalinity 100.0 conductivity 194.0 water temp 26.0 air temp 25 Hardness reading seems a bit low in comparison to other readings on the lake. Conductivity reading seems a bit high in comparison to other readings on the lake.