Contacts: Ralph Pribble, MPCA, (651) 297-1832, Doug Schultz, MDH, (651) 215-1303, Tom Conroy, DNR, (507) 359-6014

It’s not unusual for warm, shallow lakes to turn green and soupy with algae during the “dog days” of late summer. But sometimes the type of algae growing in the lake can be harmful to people or animals. That’s been the case recently on three lakes in Minnesota where toxic bluegreen algae blooms have occurred.

Late this summer a lakeshore resident on Lake Benton, in Lincoln County, reported large numbers of dead fish and said his dog had died after going into the lake and apparently ingesting algae. In July, a dog was reported to have died from contacting water thick with algae in Fish Lake near Mora, in Kanabec County. In Lake Crystal, southwest of Mankato in Blue Earth County, testing by the Minnesota Pollution Control Agency (MPCA) confirmed a toxic algae bloom.

The MPCA, Department of Health (MDH), and Department of Natural Resources (DNR) are advising people not to swim or wade in these lakes and to keep pets or farm animals out of the water until the algae clears up.

Water to Avoid!

Although blue-green algae occur in most lakes in Minnesota, the type and concentration can vary considerably from lake to lake. Blue-green algae thrive in warm, nutrient-rich lakes. Sometimes the algae become so abundant they completely dominate the lake, and all or parts of it turn bright green or bluish green, with the water taking on a “pea soup” consistency.

Occasionally these blooms turn toxic. Although blue-green algae are relatively common in late summer, most bluegreen blooms do not become toxic. They can go from harmless to toxic, and back again, without necessarily changing appearance. Sometimes winds will dissipate a toxic bloom in a short time. At other times, the wind can blow mats of floating algae to the lakeshore. Most problems occur when the algae clump near a shoreline and livestock, pets, wild animals, or birds drink the water.

Water to Avoid!

Steve Heiskary, a lake expert with the MPCA, said bluegreen blooms occur every summer, but this year seems to have had more than the usual number of toxic blooms. “Heavy rains this spring and early summer probably carried more than the usual amount of nutrients into surface waters,” he said, “and this could be why we’ve had more problems this season.”

Some species of blue-green algae naturally produce toxic substances. According to the MDH, humans and animals may experience illness or other health effects if there is skin contact with algal toxins or large amounts of algae are ingested.

The agencies recommend that people and animals should not ingest the water. Do not let children or pets enter the water. Contact with these algal blooms should be avoided. If contact does occur, the material should be washed off thoroughly, paying special attention to the swimsuit area. If your pet comes in contact with a bloom, wash off your pet’s coat to prevent the pet from ingesting the algae while cleaning itself.

Swimming in water with an algal bloom may cause symptoms such as skin rash, hives, runny nose, irritated eyes and/or throat irritation. Swallowing or ingesting water with an algal bloom may cause symptoms such as vomiting, diarrhea, or nausea; headache, throat irritation, ormuscle pain; and in severe cases paralysis, respiratory failure, or death. It may also cause seizures or convulsions in your pets.

If you suspect an animal has been affected by an algae bloom, contact a veterinarian as quickly as possible, as some of the toxins in a toxic algae bloom can kill in an hour or less, while some may take up to 24 hours to affect the animal.

Tom Conroy, a DNR Information Officer in New Ulm, said the combination of abnormally warm temperatures and the opening of Minnesota’s hunting seasons can be “a potentially dangerous situation for hunting dogs.”

Not only are there concerns about dogs ingesting toxic blue-green algae but there is also the danger that dogs can “quickly become overheated in warm temperatures,” Conroy warned. “Dogs don’t know when to quit so it’s up to the owner to make sure it doesn’t overdo it. Keep a close eye on your dog, don’t let it drink or lick algae off itself, rest it often, and have plenty of cool water on hand,” Conroy urged.

For more information on toxic algae blooms, see the MPCA Web page titled, Toxic algae can spell danger for pets and livestock.

Digital photos of fish kills on Lake Benton or Lake Crystal that resulted from the toxic algae blooms are available by contacting Ralph Pribble at 651-296-7792.

Posted in Lakes |