The town has received word that Cyanobacteria (blue-green algae) bloom was detected in Malletts Bay on November 30 - specifically, in the vicinity of Spaulding East Shore. Despite the time of year, it is still important to keep people and dogs from entering or ingesting the contaminated waters. Exposure can cause rashes and allergic reactions, while ingestion can potentially lead to severe effects. Possible signs of exposure to a toxic bloom in animals include weakness/staggering, difficulty breathing, vomiting/diarrhea, and convulsions.
You can read more about cyanobacteria at this fact sheet from the VT Dept. of Health.