In late April, Didymo cells, often called “rock snot,” were found in a section of the Au Sable River. A Michigan Department of Natural Resources statement says the didymo cells were found during monitoring by Michigan Trout Unlimited. Officials say Didymo cells can cause ecological problems.
The DNR statement says the sampling found “several didymo cells at the Parmalee Canoe Launch off North Red Oak Road and one cell just downstream at the Whirlpool access off West Cherry Creek Road.” They said that didymo cells were not found further downstream or several tributaries sampled to date."
Environmental officials expressed concern that didymo can cause ecological harm. Billy Keiper is an aquatic biologist with the Michigan Department of Environment, Great Lakes and Energy. He says didymo can grow long stalks or blooms that cover up the stream bed. That can cause problems for anglers and fish, because the didymo crowd out other food sources in the ecosystem.
EGLE, the DNR, and Michigan Trout Unlimited are still monitoring for any didymo. “These were just microscopic cells at this point. What does that mean? We really don't know,” Keiper said. “We don't know how long it's been present in the system, we don't know if this is a new introduction. It could have been there a few years, could have been there a couple decades. It's really hard to say.”
EGLE recommends that stream users and anglers clean their gear and boats after each use to stop any potential spread. “Make sure to do the proper steps to decontaminate your gear,” Keiper said. “Rinse with hot water for a few minutes — anything over 140 degrees should kill those specimens off pretty quickly. We recommend formula 409 antibacterial, an all-purpose cleaner.”
EGLE also recommends bleach and Virkon Aquatic as cleaners. The agency says anglers should use different gear for every stream and clean, drain, and dry their gear.
EGLE is asking the public to report any didymo sightings using its online reporting system.
