Great Lakes
2019 Lake Erie algal bloom. Photo by NASA Earth Observatory / Joshua Stevens

MI - New online map helps track harmful algal bloom reports in Michigan

LANSING — A new online mapping tool helps people know where harmful algal blooms in bodies of water have been reported in Michigan.

The Michigan Harmful Algal Bloom Reports map is now available online at

Harmful algal blooms (HABs) form due to a rapid growth of cyanobacteria, also called blue-green algae, which are naturally found in lakes, rivers and ponds. Toxins found in cyanobacteria (cyanotoxins) that can be found in blooms can be harmful to people and animals.

“The new Michigan Harmful Algal Bloom Reports map is an exciting tool to increase awareness of HABs and to help prevent related illness,” Dr. Natasha Bagdasarian, Michigan Department of Health and Human Services chief medical executive, said in a news release. “If you may have had contact with or swallowed water with a HAB and feel sick, call your doctor or Poison Control at 800-222-1222. If symptoms are severe, get emergency medical attention as soon as possible.”

To provide more information on HABs statewide, MDHHS and the Department of Environment, Great Lakes, and Energy developed the Michigan Harmful Algal Bloom Reports map. The map, which will be updated weekly from June to November, shows bloom reports that have been verified by EGLE and the results of any cyanotoxin tests.

Not all HABs in Michigan are reported to EGLE and some may not be included on the map. HABs can move around, disappear and reappear — meaning that HABs may be present in waterbodies, but not present on the map. Before going in any water, MDHHS recommends looking for and keeping away from visible HABs or scums and that people and pets stay out of water in affected areas.

The map does not show any current blooms in Lenawee County waterways. In counties that neighbor Lenawee, the map shows a bloom with cyanotoxins detected at Lake LeeAnn in Hillsdale County as well as blooms with cyanotoxins at Ford Lake in Washtenaw County near Belleville, Sterling State Park in Monroe County and Luna Pier Beach in Monroe County.

The occurrence of cyanobacteria and their toxins typically takes place in the summer and fall and has been confirmed in lakes across Michigan in previous years. In 2021, 79 harmful algal blooms in 43 counties were reported to EGLE.

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