We are beginning to receive reports of blue green algae concentrations on the lake.  We will be out in the field to assess the situation today and will provide an update later in the day. 

Remember: Look for visual indicators of blue green algae.  If you see anything suspicious, avoid it.  Remember that dogs are also susceptible to blue green algae and should not enter the water in suspicious bloom areas.

If you see any algae concentrations, please send  photos and a description  to HABS@canandaigualakeassoc.org.

- Kevin Olvany, Watershed Program Manager, Canandaigua Lake Watershed Council and

Lindsay McMillian, Director, Canandaigua Lake Watershed Association

The hot and sunny weather over the last few days have increased the potential for BGA blooms, however the vast majority of the lake is free of any significant concentrations of blue green algae.  

In an abundance of caution, the State Department of Health closed Deep Run and Onanda Beaches on August 24th.  The County and Town are eagerly awaiting test results to hopefully show they can re-open those beaches.  Local inspections of those beaches have shown clear conditions over the weekend and Monday- however it is only the state Department of Health that can re-open the beach.  Kershaw Beach is still open.  

The combination of our volunteer monitors, watershed staff and interested residents are indicating that the vast majority of the shoreline areas are free of any Blue Green Algae concentrations along both sides of the lake. We did see one very isolated spot about 4 feet wide along the northern
shoreline, but the rest of the north end was free of any visible...

With the hot and calm weather, we are seeing a reduction in water clarity and an overall increase in algae in multiple areas in the lake.  Yesterday, we had numerous reports of blue green algae concentrations along the shoreline on both the east and west sides of the lake.  We also observed some surface streaking in the open water.  Our secchi disk readings dropped from approximately 7 meters to approximately 4 meters in less than 1 week, indicating that more algae is in the water column and that we may continue to see blooms in the lake.

Please continue to use extreme caution before entering the lake.  Look for visual indicators of blue green algae.  If you see anything suspicious, avoid it.  Remember that dogs are also susceptible to blue green algae and should not enter the water in suspicious bloom areas.

If you see any suspicious blue green algae, please email photos and the location to:

Kevin Olvany

Canandaigua Lake Watershed Council Program Manager 


     We went out this afternoon from 1-4pm and toured the northern 6+ miles of the lake along both shorelines and mid lake areas.  There is northerly breeze of about 5mph that is improving conditions both mid lake and along the shoreline.  There were no visible signs of any surface streaking, concentrations or bloom conditions.  Lake clarity is holding at about 7.5 to 8 meters in multiple locations.  We also talked with one of our experienced volunteers who was out in the Vine Valley section of the lake and all looked good there as well.  We did see some minor dots in the water in a few locations and utilized FLCC's Blue Green Algae probe and the readings were consistently at low levels.  Based on all of our sampling to date the levels we encountered would be well below bloom conditions and would be considered low risk.

     However, conditions can change quickly on the lake, so use your visual indicators before entering the water and have a happy...

     We have received the toxin results from the 3 samples collected on Monday.  These samples were collected along the shoreline where the Blue Green Algae (BGA) was accumulating in isolated locations and are representative of the very worst case scenario areas that had the densest blue green algae.    The blue green algae chlorophyll-a in these areas were 129.5 ug/L, 364.3 and 701.3 ug/L.  The toxicity results were 117.84ug/L, 386.61ug/L and 663ug/L.  Toxin levels that are above 20ug/L are considered to be in the high toxicity category. Obviously, our results are well above the 20ug/L threshold. Therefore, individuals need to use increased caution. Exposure to high levels of blue-green algae and their toxins can cause diarrhea, nausea or vomiting; skin, eye or throat irritation; and allergic reactions or breathing difficulties. 

     The very calm wind conditions this week (including today and most likely this weekend) are allowing BGA...

     Today, we observed and had reports of blue green algae along multiple sections of the west side of the lake.  This is the first time we observed surface streaking and concentrations along multiple areas of the western shoreline.  We also observed some surface streaking along the eastern shoreline in cove areas.   The very calm and very sunny conditions today brought the algae to the surface and has allowed it to concentrate in these shoreline areas.  In other areas, dots were visible in the water column but were not surface streaking or concentrations.

     Please continue to use visual indicators for blue green algae before going into the water.  Blue green algae can concentrate in open water and shoreline areas, and conditions can change quickly on the lake. If you see anything suspicious, avoid it! 

     It is extremely helpful for any resident who sees blue green algae to take a photo and email it to us at kevin.olvany@canandaigu...

We conducted visual surveys of the shoreline today.  The wind was a gentle breeze out of the northwest so we visited multiple sites along the east side of the lake.  The water was clear and showed no signs of blooms or surface streaking.  Some dots of Blue Green Algae could be seen in the water column in one area but not at significant concentrations.  Overall conditions looked very good in the areas that we have been seen isolated concentrations of Blue Green Algae.  There seemed to be enough wind to break up any concentrations on the east side.  If anyone is seeing anything different please let us know.

Yesterday, Dr. Bruce Gilman and Watershed Technician Kim McGarry were on the lake for 3+ hours and completed field analysis and visual assessments in open water and shoreline areas. Some areas of the lake had a small amount of surface streaking and dots of algae were visible in the water column. However, we did not observe any dense concentrations like the samp...

With this warm and sunny weather, we are continuing to see an increase in blue green algae in sections of the lake.  However, our lake is not alone.  This warm weather has also trigger blue green algae in many of the other Finger Lakes.

Based on the wind patterns, we observed higher concentrations of blue green algae along parts of the eastern shoreline this afternoon.  We collected three samples and are having them analyzed at SUNY-ESF.  At the same time, other sections of the lake were clear.  We will continue to monitor the lake and will provide the results from SUNY-ESF as they become available. 

Conditions on the lake can change quickly. Blue green algae concentrations may increase throughout the day with warmer temperatures and sunlight. They also shift with the wind.  We cannot say at any given moment where algae will concentrate or where it will be clear . Before going into the lake, be sure to look for signs of blue green algae.  If you see it, avoid it.

Yesterday we had a few reports of small, isolated areas of surface streaking/concentrations of blue green algae along the east side of the lake. The warm, calm, sunny weather Tuesday and Wednesday was likely contributing to the increase in algae at the lake surface.  We checked a few spots on Thursday morning, but did not find any concentrations.  Overall lake clarity is lower than average due to higher algae concentrations.  The forecast for the next 10 days shows more sunny and warm weather to come.  Please keep an eye out for blue green algae concentrations over the next few weeks.  If you see anything suspicious, please send a photo and the location to Kevin Olvany (klo@canandaiguanewyork.gov) and Kim McGarry (kmcgarry@canandaiguanewyork.gov) at the Watershed Council. 

Remember, if you see potential blue green algae blooms, avoid it!

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More Information on Blue Green Algae

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