October 2, 2019

Over the last two weeks we have seen a gradual diminishing of blooms around the lake.  However, we did have three reports of  potential blooms yesterday with the 87 degree weather.  We also went out on Sunday September 22nd after the bloom conditions of the previous two days and sampled for toxins and blue green algae concentrations in several different locations and depths to better understand the ambient (general levels) of both BGA and the associated toxin.  The good news is that the toxin levels at each of the locations were below the 4 ug/L level that would cause the DOH to close a public swimming beach.  The other good news was that the BGA levels were low: 1-2 ug/L.  However, the concerning part was that we had detectable levels of toxin in the water even though the BGA levels were low.  There were dots in the water in each location that we sampled.  We are seeing a little more algae diversity in the water with harmless green algae and diatoms starting to show quantifiable level...

September 18, 2019

After a “quiet” week with minimal harmful algal bloom reports from volunteers and the public, activity picked back up again today, with several reports and samples collected from the west side of the lake. Photos coming in showed areas of surface streaking and shoreline accumulations of algae from several spots around the lake.  We are starting to get more algae bloom reports from the southern half of the lake. 

And while the sunny, calm, warm weather forecasted for the next several days will be great for getting in those end-of-summer activities, it is also ideal conditions for blue green algae (cyanobacteria) to pop up.  As we cannot predict when or where blooms may appear, please continue to use your visual indicators before recreating in the lake.

September has been the month when we have experienced our most significant bloom events, and last year was no exception, with many blooms being designated as “Confirmed with High Toxins”. This year, the DEC will not be releasing tox...

September 4, 2019

Yesterday we experienced significant streaking and surface scum accumulations of blue green algae (cyanobacteria) along several shoreline areas. Twelve samples were collected as part of the shoreline HABs network and were brought to the Finger Lakes Institute for screening with the Fluoroprobe. If samples come back with high levels of blue-green chlorophyll a through this screening process (confirming bloom status), they will be sent on to the DEC’s designated lab for toxin analysis. While FLI results should be forthcoming in a few days, the toxin analysis can take much longer. This emphasizes the need to use extreme caution when recreating in the lake.

Although yesterday’s blooms were not experienced lake-wide, the areas they were observed were severe in some cases. Reported blooms were seen in coves, shallow beach areas, by docks, or trapped in corners of a break wall – all areas where blooms get pushed by wave and wind action. Unfortunately, these easy-access areas are also where pe...

August 29, 2019

As we head into the Labor Day weekend, there are a lot of question on which public beaches will be open for swimming. The Department of Health has completed another round of sampling for the beaches this week, and based on the results, Deep Run Beach, Onanda Beach and Butler (Schoolhouse) Beach will remain closed at this time. Test results are indicating that the microcystin toxin levels still exceed the state threshold for re-opening, which is 4 ug/L (micrograms per liter). Kershaw beach was tested and the results allowed the beach to be reopened. At this time Kershaw Beach and Vine Valley Beach remain open.

These results emphasize the need to use caution as we head into the long weekend. Many areas of the lake are well below bloom conditions, but we know conditions can change quickly, so continue to use your visual indicators before entering the lake (check out the DEC photo gallery for examples of blue green algae). Please remember that pets are especially vulnerable to harmful alg...

August 23, 2019

We just received word that the state DOH will allow the City to reopen Kershaw Beach based on the test results from samples collected on Thursday.  However, Deep Run Beach, Onanda Beach and Butler (Schoolhouse) Beach will remain closed due to test results from samples collected Thursday indicating that the microcystin toxin levels exceed the state threshold for re-opening the beach.

The DOH also completed testing of the 6 water providers- Newark, Palmyra, Canandaigua, Gorham, Rushville and Bristol Harbor.  The test results for each of the purveyors treated (finished) water came back as non-detectable for the microcystin toxin.  The DOH will continue to work with the water providers on testing and optimizing treatment approaches.

Based on the beach testing results we strongly suggest that you continue to use caution before entering the water and that you use visual indicators to look for any signs of algae. Watershed staff and trained volunteers have been out surveying stretches...

August 20, 2019

We are seeing very different conditions today with the hot, calm weather allowing the BGA to concentrate at the surface.  We are seeing extensive blooms in the northern half of the lake.  Clarity has dropped by almost two meters in the north basin in 48 hours and we are seeing extensive blooms along the east and west shoreline and many bloom patches and lots of streaking in the mid lake area. Further south near Onanda Park, water clarity is somewhat better  with Secchi disk readings of 5.7 meters.  However, we were still seeing significant dots in the water column in this area.  We have had some reports of surface streaking in the southern half of the lake as well. 


Please use caution before entering the water.  It is very important to remember to use your visual indicators while using the lake. Please stay out of the water in areas where there are bloom like conditions. It is impossible to tell whether or not a bloom is toxic by looking at it, so...

August 20, 2019

Since Friday’s update we have had a lot of rain and some wind. That has helped to keep the surface concentrations of blue green algae (BGA) fairly low in most areas.  Please remember that this is a 10,500 acre lake with 36 miles of shoreline- so there can be some significant variability.  Both watershed staff and volunteers were active over the weekend and today completing surveys and research on the lake.  I was out with DEC staff on Sunday sampling multiple sections of the northern third of the lake and there were low concentrations (well below bloom threshold) levels of BGA.  We did have a volunteer collect one sample this morning in the Crystal Beach area that had a concentration above bloom levels.  That sample has been sent for further testing for toxins.  However, the vast majority of the lake is not seeing bloom conditions at this point (that can change quickly). 

We also had three beach closures on Friday- Deep Run beach on the east side, Schoolhou...

August 16, 2019

With the calm winds and hot temperatures today, we are starting to get additional reports of surface streaking and significant dots in the water both along the shoreline area and in the middle of the lake.  Conditions today and through the weekend are ripe for additional concentrations of algae and there is a likelihood of more extensive blooms.   

Out of an abundance of caution, Deep Run Beach in the Town of Gorham and West Lake Road School House Beach in the Town of Canandaigua have been closed. The beach operators will continue to work with NYS Department of Health and will conduct follow up testing.

Remember: Use visual cues to identify harmful algae blooms. They can appear like pea soup, spilled paint, globs, and parallel surface streaks and significant dots in the water column. Visit theDEC photo galleryfor examples. 

If you see anything suspicious, avoid it. Remember that dogs are also susceptible to harmful algae blooms and should not enter the water in suspicious bloom...

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

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More Information on Blue Green Algae

Click below for our Harmful Algae Bloom brochure.

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