The past two years saw unprecedented numbers of cyanobacteria warnings in New Hampshire. And, so far, it seems like 2025 is set for another big bloom year.
According to Amy Smagula, chief aquatic biologist at the state Department of Environmental Services, about 52 reports of cyanobacteria blooms have already been recorded this year.
Read more about the connection between our changing climate and cyanobacteria blooms.
Cyanobacteria blooms release harmful toxins that can cause mild to life-threatening diseases. According to the Centers for Disease Control and Prevention, some of the most common symptoms include vomiting, diarrhea, headache, rash and cough.
To stay safe, Smagula urged people to keep this mantra in mind: “Look. Check. Report.”
- Look: Water with green, blue, white or red patches, or with areas that resemble the inside of a snow globe, can contain cyanobacteria. Water that smells odd or fishy could also be a sign. If you notice a lot of wildlife nearby, such as ducks or geese or even dogs, it’s also best to avoid swimming. You should also check for any signs around the area for potential cyanobacteria warnings.
- Check: Search the Healthy Swimming Mapper website for any active warnings or watches of cyanobacteria blooms. That site has recently been updated to show more localized information, so you can now see the exact spot where a bloom was reported in a water body.
- Report: If you notice the water looking strange but don’t see any reports on the map, make sure to fill out a bloom report. Cyanobacteria blooms evolve quickly, so sending these reports helps the Department of Environmental Services provide the most up to date information.
