The North Dakota Department of Environmental Quality earlier this month issued Harmful Algal Bloom warnings for Stump Lake and South Golden Lake in the northeast part of the state. A warning for Mount Carmel Dam was set to be lifted Tuesday morning.
Triggered by warmer weather and rising water temperatures, blue-green algae can be toxic to humans and domestic animals that consume or come in contact with water where the harmful toxins, known as cyanotoxins, are present, the department said. Symptoms can include diarrhea and vomiting, numb lips, tingling fingers and toes, dizziness, rashes, hives or skin blisters. Pets and livestock also may suffer adverse health effects.
Warnings also are in place for Alkali Lake in Sargent County, Lake LaMoure, Antelope Lake, Warning Sign Lake and Patterson Lake.
There are no known antidotes for the cyanotoxins produced by blue-green algae, the department said, and children and pets are at a higher risk because of their smaller size.
Blue-green algae can look like green scum, grass clippings, crust, puff balls, spilled paint and cottage cheese, the department said. People should avoid bodies of water where warnings are in effect, though areas where the algae isn’t present generally are considered safe.
Advisories, where toxic algae is approaching harmful levels, are in effect for Lake Renwick, Homme Dam, Wood Lake and Devils Lake, the department said. Toxin levels are low in Fordville Dam and Larimore Dam, according to a map on the department's website. An earlier version of the map, which indicated levels were low in East Bay and Black Tiger Bay of Devils Lake, was incorrect and updated Tuesday, said Jim Collins, an environmental scientist in the department's Division of Water Quality.
As of Monday, Aug. 24, the department also was investigating algae reports on Lake Josephine in central North Dakota and Lake Trenton in the northwest part of the state.
Minor fish impact so far
In addition to increased risk from toxic algae, high water temperatures can result in fish kills, and most of North Dakota – unlike the Red River Valley – has been dry, said Greg Power, fisheries chief for the North Dakota Game and Fish Department.
Despite the conditions, there has only been one “minor” summer fish kill to date, Power said, a trend he considers “pretty incredible,” considering the abundance of algae in some lakes. Last fall’s heavy rains may have buffered the impact of dry conditions and warm temperatures, he said.
Until conditions improve, the Department of Environmental Quality recommends that people be cautious and avoid waters that appear discolored, scummy or smell bad.
“When in doubt, stay out,” the department advises.
Anyone encountering suspected blue-green algae blooms should contact the Department of Environmental Quality at (701) 328-5210 or make a report on the department’s Harmful Algal Bloom webpage at www.tinyurl.com/WMP-HABS.