ROCHESTER, NY (WROC) – Algal bloom trends are down for some lakes and up for others, based on NYS DEC tracking data. Below are the details of how some of the lakes are trending over the last year and what we might attribute to that trend. 

Toxic algae is becoming a bigger threat to the Finger Lakes thanks to climate change, farming practices, lawn care, and other environmental threats. Harmful Algal Blooms (HABs) often occur as excess nutrients mix with warm, stagnant water over long periods of time, something that will be more prevalent in the Finger Lakes because of a warming climate, according to the EPA.

NYS Department of Environmental Conservation now tracks cyanobacteria, (what makes algae toxic) and this data can be used to help understand trend lines. Records of HABs go back to 2012, with the number of HAB reports beginning in 2020. An analysis of eight of the Finger Lakes (Conesus, Hemlock, Canadice, Honeoye, Canandaigua, Keuka, Seneca, & Cayuga) shows that nearly all lakes saw a decrease in reports of blooms from 2021 to 2022. Keuka was the only lake to see an increase from 12 to 14 reports. 

This bloom was reported on Canadice Lake by the public through the NYSDEC on October 5, 2022.

Analysis of 2021 bloom reports shows that the last report date can vary from Late September to a rare early November report. The average last date of reporting a harmful algal bloom from the eight lakes is October 13. The two lakes with the highest number of reports were Cayuga at 117 and Canandaigua at 84. Both lakes saw a significant drop in reports this year with Cayuga falling to 82 and Canandaigua to 17.  

The human element is important to mention. Blooms need to be spotted, reported, and verified. The willingness of the reporter factors into the number of reports as well as frequency of visits to a specific lake. Variable weather patterns will also have something to do with HABs. 

According to Climate data from the Rochester airport weather station, 2021 came in as the 12th warmest on record going back to 1926 with an average of 71.4° over the June/July/August time frame. 2022 was “cooler” with an average of 70.7° (20th warmest). That may have contributed to the number of reports going down.  

Rainfall should also be taken into consideration. 2021 was a wet year, with the summer months clocking in at 11.94”, 17th wettest in nearly 100 years of record. Much less rain fell in 2022, 7.19”, ranking 69th. More rain means more runoff of chemicals into bodies of water. That means more nutrients for the plants to grow. 

Final reports will be put together at the end of the year, but this is a good early glimpse at how toxic algae may be influenced in the Finger Lakes in the years to come. Better detection and awareness may be the most important when it comes to preventing these blooms.