According to the CBC, Ecologists are warning people in Fredericton that a blue-green algae bloom may be behind the sudden deaths of three dogs that died after swimming in the St. John River.
New Brunswick's provincial veterinarian, Dr. Jim Goltz said it isn’t confirmed, but he suspects toxins from blue-green algae are the cause of death.
The article states that “New Brunswick isn't the only province contending with the potentially deadly microbe. At least 246 Canadian bodies of water have been shown to have high concentrations of blue-green algae at various times in the last 15 years.”
Blue-green algae is a bacteria (scientific name: Cyanobacteria) that can produce toxins harmful to people and animals. It typically grows rapidly in areas where there is an abundance of nutrients like phosphorus and nitrogen.