The Kalamazoo County Health & Community Services Department, in consultation with the Michigan Department of Health and Human Services, is warning the public of potentially toxic conditions of a lake in Portage, Michigan. 

Sampling was performed Tuesday, October 3, 2023, on water taken from Austin Lake, which lies between Portage Road and Sprinkle Road, just south of East Centre Avenue. It is suspected that the water contains a harmful algal bloom (HAB). The results came back positive for microcystin, which is a variety of cyanobacteria that can produce toxins. 

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Additional Testing Is Being Performed 

Additional testing is being performed on the positive samples taken from Austin Lake for confirmation and microcystin levels. In the meantime, people and pets should avoid swallowing the lake water, and avoid direct contact with water that appears blue-green, or water that looks like it has a green sheen or spilled paint on its surface. 

Is The Lake Safe For Boating? 

Authorities say that recreational activities can still take place on the lake. You just need to avoid contaminated areas. A press release from Kalamazoo County Health & Community Services Department advises, 

The State of Michigan Bureau of Laboratories will test the positive samples from Austin Lake for confirmation and microcystin levels. Recreational activities on the lake may continue while taking the precautions noted above. 


HAB Can Appear As A Blue-Green Sheen or "Spilled Paint"

Harmful algal bloom can appear as a blue-green sheen, or "spilled paint", on the water surface.
National Parks Service via Wikimedia Commons

What If My Pet Wanders Into The Lake? 

If you happen to be at Austin Lake, do not allow your pets to come into contact with contaminated water. If they happen to wander into contaminated water, it is very important to rinse your pets off with fresh water after they have come into contact with a suspected HAB. 

What Are The Symptoms Of Exposure To HAB? 

HABs usually occur during the summer and into the fall. The problem with recreational water sports is that they can worsen the impact of HABs by creating water spray which may cause additional skin, eye, nose, or throat irritation. Swallowing large amounts of water containing cyanotoxins may cause the following symptoms in humans: 

  • Stomach pain 
  • Vomiting, diarrhea 
  • Weakness, numbness 
  • Headaches, dizziness 
  • Difficulty breathing 

What Are The Symptoms For Pets? 

Symptoms of illness from cyanotoxins often appear quicker in animals, sometimes within minutes to a few hours, and death can occur. The symptoms can include: 

  • Vomiting, diarrhea 
  • Fatigue, staggered walking 
  • Excessive drooling and convulsions 

Austin Lake Is Not The Only Southwest Michigan Lake Affected 

According to the HAB map, provided by the Department of Environment, Great Lakes, and Energy, two additional Southwest Michigan lakes are affected by HABs. At Swan Lake, in Allegan County, cyanobacteria has been verified and cyanotoxins were detected within the last 14 days. Also, Lake Allegan, in Allegan County, has cyanobacteria verified, however, cyanotoxins were not detected within the last 14 days. 

To help identify a HAB and other lake conditions that are mistaken for HABs, you can visit the official HAB Picture Guide. If you have questions about eating fish in an HAB area and for HAB prevention, visit 

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Gallery Credit: Jacob Harrison

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