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Rock Snot Algae Found to Be Native to the U.S.

Burlington Free Press

Well, the Vermont rock snot scare is over.

The aquatic algae called rock snot was found to be native to the northern United States.

The Vermont Department of Fish and Wildlife found that the rock snot spores are present in many of the local rivers. It was not a toxic sludge from an unknown polluter and it was not an invasive species. It was there all along and can cause the nuisance algae blooms when the requirements are met. Those requirements would be low nutrient waterways that are usually  in pristine condition as reported.

TVA biologist Tyler Baker shows a handful of Didymosphenia geminata, commonly known as didymo, a diatom found on the Clinch River in the tailwaters of the Norris Lake. A common name for the nuisance species is rock snot.
Knox News

The aquatic algae has been spotted by anglers in Vermont since 2007. The panic that surrounded these algae blooms caused felt bottomed waders to be banned. It was worried that spores or other invasive material might get transported from waterway to waterway on the feet of anglers.

Southern Maryland Fishing

Now that the culprit has found to be an aquatic algae named Didymosphenia geminata the state of Vermont is poised to once again allow felt-bottomed waders to be used in the waterways next month.


Some groups like the White River Partnership are not happy about lifting the ban on felt-bottomed waders. They feel the ban is a good idea to help stop the spread of other invasive species that just might hitch a free ride. The executive director Mary Russ states:

"We were thinking that it was a good management strategy."

Vermont State biologist Shawn Good counters:

"The fact that we had a ban on something to avoid spreading something that was already where we didn't want it to be spread didn't make any sense."

If you see what appears to be a nasty sewage spill, take a closer look. Rock snot grows on rocks in the river bottoms. It actually has a wet woolly texture as opposed to its slimy appearance.

The Vermont Fish and Wildlife Department reminds anglers that even though felt bottom waders are once again legal to use keep it clean. Make sure to clean and dry all gear always to keep from spreading any species from body of water to body of water.


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Rock Snot Algae Found to Be Native to the U.S.