On Friday, July 24th, a visitor on the lake called the Ministry of Environment, Conservation & Parks (MECP) with concerns related to blue-green algae and the Ministry sampled the water at a location in Falkenburg Bay.
The Brandy Lake Association was in contact with MECP on Monday, July 27th, and they confirmed that blue green algae was identified, and that they would contact the BLA as soon as the results were available. They emailed the BLA on July 29th, that they had identified the blue-green algae Woronichinia. This is a different genus than was detected in September of 2019.
The sample was forwarded for further analysis for toxins. Blue green algae that is non-toxic is not a health risk. MECP contacted the Association on August 17th, 2020, to share that the results confirm the bloom was not toxic.
The original sampling results were also forwarded to the Simcoe Muskoka District Health Unit (SMDHU) on July 29th, and as a result, they have published an advisory. There are currently 19 lakes that have been confirmed with blue green algae occurrences in the MECP Barrie District; we are not alone with blue green algae issues in 2020.
We encourage you to read and understand the health risks related to blue green algae, posted on both the SMDHU website http://www.simcoemuskokahealth.org/Topics/SafeWater/bluegreenalgae_copy1.aspx#f0106af6-4016-47ad-9deb-8e262ab6e3b5#cacaf8a4-78aa-430c-90db-75eff852b432 and the BLA website https://brandylakemuskoka.ca/.
July and August in Muskoka have been very hot and relatively dry with insufficient wind in Muskoka. In July, there were 7 days of temperatures recorded above 30oC; the average number of days above this temperature in July in the past two decades is 1.3. There was also very little rainfall, the lake water level is low, and there was relatively little wind. These factors have all contributed to create favourable conditions for algae.
It is important to understand that while MECP confirms the presence of algae, MECP does not “fix” or “remove” algae. This is a natural process in the lake, and our only ability to influence the outcome is to limit activities that contribute to its growth. Some of the contributing factors are detailed below.
As part of the BLA’s strategic planning work, we are currently gathering and monitoring scientific data in and around Brandy Lake, and hope to develop some additional monitoring that will help us to understand the natural processes of the lake in more detail.
Additional Blue Green Algae Information
Blue Green Algae: Important Overall Points to Consider
While it is important to know that blue green algae were documented in Brandy Lake in 2019 and now in 2020, the following information provides additional context to the recent sampling;
- All lakes contain blue green algae all the time; they are an important part of the aquatic food web.
- Lakes like Brandy Lake (dystrophic lakes that are tea stained with lots of dissolved carbon and poor light penetration) are not generally known for having blue green algae blooms. The last recorded blue green algae event on Brandy was in 2003.
- Phosphorus is an important component in the occurrence of algae blooms; phosphorus is required for the algae to consume.
- Conditions that encourage algal blooms often include;
- Sufficiently high levels of nutrients (specifically phosphorus) in the water or sediments
- Calm weather
- Strong sunlight
- High air and surface water temperatures
- Other factors that may affect algal blooms include wind, major rainstorms, and spring flood conditions.
- Phosphorus in Brandy Lake is decreasing. This is identified in the regular spring water sampling conducted by the Association.
How Can Brandy Lake residents manage Brandy Lake to reduce nutrients?
Human activity can contribute to high phosphorus levels in lakes. It is very important that all Association members participate in activities that promote continued lake health especially with respect to the shoreline areas, such as;
- Do not remove aquatic vegetation from the lake; vegetation plays an important role in the uptake phosphorus and other nutrients, making it unavailable to the algae in the lake.
- Limit boat wake in shallow parts of the lake. Scientific studies have revealed that the stirring up of lake sediment by boat props may contribute to algal growth by releasing nutrients into the water.
- Ensure that plant material (grass clippings, brush, yard waste, etc.) are not stored near or disposed of in the lake. This adds nutrients to the lake, which increases phosphorus available to algae.
- Ensure that your shoreline is not eroding. Planting vegetation along the shoreline helps stabilize the soil and makes it more resistant to erosion, which adds nutrients to the lake.
- Ensure that you perform regular maintenance on your septic tank. Leakage could be a contributing factor to the increase of unfavourable nutrients in the lake.
- Avoid use of fertilizers and herbicides on properties with shoreline.
- Work to replace lawns with naturalized shorelines to prevent run off of nutrients that will enter the lake and feed algal growth.