Confirmed Cyanobacteria

On Wednesday, 8/26 I walked down to my swimming beach area to find what looked to be a Cyanobacteria bloom. I took some photos, took a sample and reached out to Maria Gross who came over to take a look. We agreed it should be reported and I filled out the online form and submitted it to NHDES. Within the hour and a half after I saw it, it had cleared and I could not find any evidence even along surrounding shorelines. Someone from NHDES called and we arranged to meet halfway between Concord and Conway to pass my sample along. By that afternoon, it was posted on The NH Healthy Swimmer Mapper that what was collected was indeed Cyanobacteria, specifically Dolichospermum which is a genus of Cyanobacteria (blue-green algae) found in freshwater bodies. Here is the link to the mapper 2026 NHDES Healthy Swimming Mapper

Today, I received a call to confirm that it was a Cyanobacteria bloom, the sample will be frozen and studied again over the winter. The NHDES advised that I keep children and pets out of MY beach water and when I asked if that would apply to surrounding areas and the lake in general, she said no. I will need to monitor my beach for the next few weeks and report it again if I see a new bloom. I asked if there was something I was doing to cause the boom and she said no, this is naturally occurring and it happens all over the state in a variety of water bodies.  I have been diligently checking every day, multiple times a day since my initial sighting and still have not seen any evidence of a new bloom. I will update people if I see it again and ask that everyone report if you see something unfamiliar! If you have specific questions please send emails to  HAB@des.nh.gov or call:  (603) 848-8094