Water Quality Update for July 23, 2021

Water Quality Update for July 23, 2021 

In this issue:

  • Water Quality Update for 7/23/21
  • What are those Flag Markers Close to Shore?  
  • Boating Advisory from the Ontario County Sheriff


Water Quality Update : Current Conditions 

Welcome to your Friday Water Quality Update. This week, we are happy to report there were no blooms observed by volunteers or watershed staff.  

Since last week’s edition, we have experienced some intense rain events across the Finger Lakes. These rain events have flushed an abundance of duckweed and watermeal from the West River and other tributaries, which can easily be mistaken for a harmful algae bloom (HAB). See photos below. 

Duckweed and watermeal (Lemna spp. and Wolfia spp., respectively) are tiny floating aquatic plants that are among the smallest flowering plants on earth. They are native to our local ecosystem, and can proliferate rapidly. Often, the two species will be found together on the water’s surface, and may clump together or form into long “streaks”. These streaks can sometimes be observed in large swaths running down the length of the lake! Prevailing winds may also push duckweed and watermeal into coves or along shorelines and can easily be mistaken for a HAB, especially when observed from a distance.  

Image 1: Watermeal from 7/15 in Cottage City – Not a HAB

Image 2: An image submitted by a lake resident on July 16th – Not a HAB

Image 3: CLWA HABs Team Leader Sally Napolitano laid a piece of paper over the water in an area of observed duckweed. . What adhered to the paper is mostly watermeal, but the larger “dots” are duckweed. Microcystis which usually comprises the HABs we see here on Canandaigua Lake are smaller than this by magnitudes. Not a HAB.


Duckweed and watermeal do not produce toxins and are not harmful to human or pet health. However, during HABs season, you may sometimes see these aquatic plants mixed in with a harmful algae bloom. In that case, they should be avoided. 

If you have a question on a suspected bloom, please feel free to send in a photograph to HABs@canandaigualakeassoc.org. This email address is monitored by CLWA and our Watershed Program Manager, Kevin Olvany, at the Canandaigua Lake Watershed Council. We may be able to assist with identification though a clear photograph. 

Please continue to use your visual indicators to look for signs of active bloom conditions. As recommended by the DEC, if you see it, avoid it.

Volunteers and watershed staff will be continuing daily observations throughout July, August and September and we will communicate any significant changes in bloom activity through our weekly email updates, on our website, and on our facebook page. 

Enjoy your weekend!

What are those flag markers close to shore? 

Boaters or waterfront residents may have noticed orange flags in several areas around the lake recently. These flags are marking buoys for gill nets, placed by the DEC Fisheries. 

The DEC has been performing standard lake trout netting to help fisheries biologists track the lake trout population and monitor growth, stocking success, natural reproduction, among other markers of fish health.

DEC performs these surveys every few years and compares results from previous netting surveys to track the density of lake trout populations. Survey information is used alongside Angler Diary data and forage fish (smelt, alewife, sculpin, etc) data to determine if lake trout stocking rates need to be adjusted. Brown trout and rainbow trout are also an important component of the trout fishery which need to be considered when the DEC evaluates stocking levels. 

To read more about the DEC’s Angler Diary Program, visit: https://www.dec.ny.gov/outdoor/27875.html 

Boating Advisory from the Ontario County Sheriff

The Ontario County Sheriff’s Office released a boating advisory on July 19th, 2021 for Canandaigua and Honeoye Lakes regarding the presence of debris and logs in the lakes due to the amount of rainfall received last weekend. Boaters should proceed with caution in the water and are encouraged to report areas that may pose a hazard. See the full advisory in the image below.