PIERRE, S.D. — As the “dog days” of summer roll on, South Dakota Game, Fish and Parks (GFP) officials would like to warn pet owners of blue-green algae blooms appearing in ponds and lakes across the state.
“Blue-green algae blooms happen every year when summer really gets hot,” said GFP regional fisheries manager Mark Ermer in a news release. “It’s nearly impossible to tell if algae in a pond or lake are poisonous or not, so we recommend not letting dogs swim in a body of water that has a visible layer of thick, floating algae on the surface. Even one drink of water that has a blue-green algae bloom can be fatal for dogs.”
Though most often a blue-green color, the algae can also be blue, green, reddish-purple or brown.
“Blue-green algae blooms are caused by cyanobacteria, which grow particularly well in slow-moving or stagnant water with high phosphorus or nitrogen content,” said South Dakota assistant state veterinarian Mendel Miller in a news release. “Some of these cyanobacteria may produce dangerous toxins which, if ingested, can lead to liver or nervous system damage in animals. These toxins cause serious damage quickly, so prompt medical care is critical following potential exposures.”
Because it is not easy to tell if an algae bloom is producing toxins, it is best to avoid all water where cyanobacteria appear to be present.
“If you think you or your pet has come into contact with blue-green algae, contact your doctor or veterinarian immediately,” Miller said. “Symptoms of blue-green algae poisoning include, lethargy, the inability to walk, hyper-salivating, weakness, vomiting, diarrhea, pale gums, shock, seizures, loss of appetite, tremors and difficulty breathing.”
The toxins can also be present in fish caught during a bloom, though research has shown the concentrations of toxins are higher in the organs of fish than in the muscle tissue or fillets. Toxin levels decrease after an algae bloom has ended, but fish consumption from lakes experiencing a high algae bloom should be limited.
Anyone observing what they believe is a harmful algae bloom should contact their local GFP office or the South Dakota Department of Environment and Natural Resources at 605-773-4729.