Anglers on the St. Mary’s River near Sault Ste. Marie have been pulling up large mats of an invader algae called Didymosphenia geminate, better know as didymo. The unusual species of algae has been detected for the first time in Michigan, in the St. Mary’s River, according to the Michigan Department of Environmental Quality.
The Department of Fisheries and Oceans Canada also confirms that didymo has been collecting on lamprey traps in the main rapids.
The algae look like toilet paper or wadded up paper and forms thick yellow-brown mats along river bottoms.
Didymo cells have been recorded in western Lake Superior for decades, but didymo blooms have only been reported in recent years in a handful of streams on western Lake Superior. Scientists suggest that Didymo may be expanding its range and experiencing novel environmental conditions that trigger the nuisance blooms.
According to Lake Superior State University environmental science professor Dr. Megan Kelly, didymo is unlike other species of nuisance algae. It typically thrives in cold, clear, flowing waters with low concentrations of nutrients such as phosphorus.
Prevention of the blooms in the St. Mary’s and surrounding streams is critical for the continued enjoyment of our aquatic resources, she said.
Anglers are being asked to help reduce the spread of didymo blooms by avoiding the use of felt-sole waders, and by drying and cleaning their fishing equipment after each use.
Felt-bottomed waders are of concern because their texture aids the spread of didymo and other aquatic invasive species.
To prevent spread of aquatic invasives, anglers should thoroughly clean their waders and fishing gear with dish detergent in hot water and dry them for at least 48 hours or freeze them for 24 hours before using them in another water body.