In late April, the invasive alga known as didymo, or "rock snot," was discovered in Michigan's Au Sable River, raising concerns with environmentalists and the local fishing community.

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This finding has been confirmed by the Michigan Department of Natural Resources and is a big concern because of the potential ecological impact on the river's ecosystem.

What Is Didymo "Rock Snot"?

Didymo, known as Didymosphenia geminata, is a type of freshwater algae that thrives in cold, low-nutrient streams and can form dense mats on the river bed, resembling wet toilet paper or brown shag carpet,

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Credit: Canva
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These mats can smother food sources for aquatic insects and fish, disrupting the local habitat and degrading the quality of fishing spots.

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Credit: Canva
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The presence of didymo in the Au Sable River, a renowned trout fishing destination, could have terrible effects on its sports fish populations and the aquatic ecosystem.

How Is Didymo "Rock Snot" Spread?

Didymo is primarily spread by anglers and boaters who fail to properly clean and disinfect their gear between uses.

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Credit: Canva
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The Michigan Department of Natural Resources and other agencies are urging the public to take precautions to prevent the further spread of this invasive species.

Stop The Spread of Harmful Species Like Didymo

take these steps when you're done fishing or boating:

Clean, Drain, and Dry

  • Clean your waders, boots, boats, and other gear to remove any mud, plants, or other debris.
  • Drain all water from your equipment.
  • Fully dry your gear before using it again or moving to a new body of water.

Use a Disinfectant

  • In areas with known invasive species, use a chemical disinfectant on your gear.
  • Some effective disinfectants include:
    • Formula 409 Antibacterial All-Purpose Cleaner - Soak for at least 5 minutes
    • Bleach solution (1 oz bleach per 1 gallon water) - Soak for 20 minutes
    • Virkon Aquatic (20 grams per liter of water) - Soak for 20 minutes

Always apply disinfectants on land, away from the water, to avoid contaminating the waterways.Taking these simple steps can help prevent the spread of invasive species and protect our waterways.

Michigan Crime Watch: Alarming Statistics by City, Part One A-B

The FBI's annual crime report includes a vast amount of information, while this gallery focuses on ten different types of crime: violent crime, murder-nonnegligent manslaughter, rape 1, robbery, aggravated assault, property crime, burglary, larceny-theft, motor vehicle theft, and arson. Here is PART I of Michigan Crime A to Z: Annual Crime - Addison to Burton

Gallery Credit: Scott Clow

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The FBI's annual crime report includes a vast amount of information, while this gallery focuses on ten different types of crime: violent crime, murder-nonnegligent manslaughter, rape 1, robbery, aggravated assault, property crime, burglary, larceny-theft, motor vehicle theft, and arson. Here is PART II of Michigan Crime A to Z: Annual Crime - Cadillac through Durand.

Gallery Credit: Scott Clow

Michigan Crime Watch: Alarming Statistics by City, Part Two C-D

The FBI's annual crime report includes a vast amount of information, while this gallery focuses on ten different types of crime: violent crime, murder-nonnegligent manslaughter, rape 1, robbery, aggravated assault, property crime, burglary, larceny-theft, motor vehicle theft, and arson. Here is PART II of Michigan Crime A to Z: Annual Crime - Cadillac through Durand.

Gallery Credit: Scott Clow

Michigan Crime Watch: Alarming Statistics by City, Part Three E-H

The FBI's annual crime report includes a vast amount of information, while this gallery focuses on ten different types of crime: violent crime, murder-nonnegligent manslaughter, rape 1, robbery, aggravated assault, property crime, burglary, larceny-theft, motor vehicle theft, and arson. Here is PART III of Michigan Crime A to Z: Annual Crime - East Grand Rapids - Huron Township.

Gallery Credit: Scott Clow