The surface of Georges Pond in Franklin get churned up by a jet ski during a severe algae bloom in the pond in June 2018. Credit: Courtesy of Lisa Branch

Toxic blue-green algae in lakes and ponds has caused the death of several dogs throughout the United States and Canada in the last month. While these algal blooms are more common in southern states, they also occur in Maine, especially as bodies of water warm in mid-to late-summer.

“The toxins, if they’re concentrated enough, are very potent,” said Scott Williams, executive director of the Lake Stewards of Maine, an organization that monitors Maine’s lakes with more than 1,300 volunteers. “This is a problem that should be taken very seriously, but at the same time, people shouldn’t be pushing the panic button.”

Blue-green algae is a type of photosynthesizing bacteria called cyanobacteria, Williams explained. It exists in all Maine lakes but is harmless in low concentrations.

[Do you have questions about blue-green algae and how it can affect dogs? Ask us here.]

When the population of this bacteria explodes during an algal bloom it can sometimes produce toxins that, when ingested, can kill dogs in a matter of minutes. It can also poison humans, causing illness and, in rare cases, death.

“It’s something we talk about on a regular basis both as professionals and also with our volunteers,” Williams said. “We do have lakes that experience annual or near annual algae blooms here in Maine.”

Credit: Aislinn Sarnacki

How blue-green algae kills dogs

The threat of blue-green algae created headlines earlier this month when three dogs died after swimming in a pond filled with toxic algae in North Carolina. The dogs’ owner posted about the event on Facebook, and her story was shared across the country.

Just two days later, a border collie died from the same type of poisoning after swimming in a lake in Georgia. And in late July, blue-green algae caused the deaths of three dogs playing along the edge of the St. John River in New Brunswick.

“I don’t know of any cases in Maine,” said Ai Takeuchi, a veterinarian at Lucerne Veterinary Hospital in Dedham. “I did ask some of the other [veterinarians], and they said sometimes they’ve suspected cases along the coast, but there are no confirmed cases we’re aware of.”

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Takeuchi and other Maine veterinarians are aware of the problem and keep an eye out for canine patients displaying any symptoms of this type of poisoning.

“It comes on very quickly,” she said. “With the algae, it can be 10 to 30 minutes after drinking the water where they start having symptoms.”

Vomiting, diarrhea, lack of coordination, seizures and excessive drooling are among the common symptoms.

“Within an hour, they’re losing consciousness,” she said. “Then, as it progresses, some of the toxins will cause acute liver failure, so they can have bleeding from gums or bloody nose, or their vomit or diarrhea will turn bloody.”

There is no antidote, she said, but if caught early, a dog might be saved through decontamination procedures and blood or plasma transfusions.

“But who can get to a veterinary hospital within 30 minutes?” she said. “That’s what’s scary about it. It’s up to the owner to get the dog to vomit and rinse the dog off and get it to a vet facility. Most of the time it’s fatal.”

Credit: Courtesy of the Maine Department of Environmental Protection

Blue-green algae in Maine

Algal blooms occur when water warms and certain nutrients, such as phosphorus, are present, Williams said. In Maine, severe algal blooms are much less common than in southern states because the water is colder and usually contains a low percentage of the nutrients that contribute to the growth of algal blooms.

Currently, 122 Maine lakes and ponds are listed by the Maine Department of Environmental Protection as being at risk for having an algal bloom. Of those, 19 lakes and ponds are reported to have algal blooms nearly every year — but not all algal blooms contain blue-green algae, and of those that do, not all contain toxins.

[Algae bloom turns Hancock County pond into a mucky green mess]

“Relative to the rest of the country, we’re in pretty good shape,” said Williams, pointing out that Maine is home to about 6,000 lakes and ponds. “Historically, we have some of the clearest and cleanest lakes in the country.”

But that could change in the future. Development of watersheds can flush nutrients into bodies of water. And rises in temperature due to climate change may make Maine lakes and ponds more apt to experience algal blooms.

“Lakes are warming up sooner and staying warmer longer,” Williams said. “Over time, that will very likely favor cyanobacterial blooms.”

How to identify toxic blue-green algae

The good news is, blue-green algae or cyanobacteria is fairly easy to spot. It received its name because dense growths of it turn water cloudy green, blue-green or brownish-green.

“There’s typically a very direct relationship between how clear the water is and the concentration of algae,” Williams said. “In our lakes in Maine, there’s a huge range of lake water clarity and much of that is natural, but when a lake’s transparency or clarity is reduced to about 2 meters, that’s the threshold that Maine uses to define a severe algal bloom.”

Therefore, if you’re standing up to your chest in lake water on a sunny day and can’t see your feet, you may be in the midst of an algal bloom, Williams said.

It also might smell bad.

Fortunately, toxins produced by cyanobacteria are not absorbed readily through the skin, according to the DEP. People with sensitive skin can develop a rash or allergic reaction. It’s ingesting the water that will cause real health problems.

Also, keep in mind that wind often sweeps algal blooms to collect along the shoreline.

“You might have something foamy looking and intensely green,” Williams described. “Something like that should always be avoided.”

To report an algal bloom in Maine, contact the DEP at 207-287-7688, and for information on health effects of cyanobacteria, contact the Maine Environmental and Occupational Health Program at 866-292-3474.

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Aislinn Sarnacki is a Maine outdoors writer and the author of three Maine hiking guidebooks including “Family Friendly Hikes in Maine.” Find her on Twitter and Facebook @1minhikegirl. You can also...