Courtesy phooto Sara Solberg, communications coordinator with the Schoolcraft Conservation District, Manistique, power washes a boat before it goes into Dodge Lake. The conservation district held an education day at the Dodge Lake Boat Launch July 6, demonstrating how to clean boats of invasive aquatic species so they don’t spread to other lakes. Invasive Eurasian Watermilfoil has been found in Dodge and Island Lakes. (Courtesy photo)

MANISTIQUE — Those of us blessed to live in the U.P. may think that invasive aquatic species are only found someplace else, not in our ‘pristine peninsula.’ But many residents of Schoolcraft County only have to look in their backyards to learn that idea is misguided.

Invasive Eurasian watermilfoil (EWM) was identified in Dodge and Island lakes in central Schoolcraft County about three years ago. It started at the Dodge Lake boat launch and in that time has spread to encompass much of the shoreline of Dodge Lake, into the channel that connects the lakes, and is beginning to spread through Island Lake.

On June 18, the Dodge and Island Lake Property Owners Association in partnership with the Schoolcraft Conservation District, began what promises to be a long battle to control the invasive milfoil. The POA hired Aquatic Biologists of Fond du Lac, WI to treat the lakes with the herbicide Navitrol to stop the weed’s spread. The POA hopes to treat again next year, using a more aggressive herbicide that should keep the invasive milfoil under control for two to three years before treatment will have to be repeated.

“Eurasian watermilfoil is an invasive plant that grows quickly and forms thick mats. The mats block sunlight to native aquatic plants and kills them. It’s a big concern for recreation, since the mats make it difficult to navigate with boats. It can grow thick enough that it creates a hazard for swimmers who get tangled in the thick mats, panic and can drown,” explained Sara Solberg, communications coordinator with the Schoolcraft Conservation District.

The thick mats also deplete oxygen in the water, disrupting fish habitat and killing fish.

“Once the infestation of EWM is in a public waterbody, it is really difficult and costly to eradicate because of (product) costs and permitting restrictions,” said Robb Langjahr with Aquatic Biologists, “That is why education, monitoring and awareness are so important.”

The Navitrol that was used in June on Dodge and Island lakes was donated by Nufarm, a company that employs POA member Ben Bottorff. Even with that donation, treatment costs exceeded $4,400. The Schoolcraft Conservation District awarded the POA a $1,000 grant to help with costs. Next year’s costs will be closer to $18,000, based on estimates received by the POA this year.

“There’s no way to eradicate Eurasian watermilfoil,” said Solberg. “Chemical treatment is best for large areas. Smaller patches can be hand pulled.” But she also notes that it only takes a tiny fragment of the invasive weed to allow it to spread.

As is often the case, prevention is the best cure. Solberg said the conservation district received a Michigan Sea Grant two-year grant to conduct educational sessions at boat landings in Schoolcraft and Delta counties. The grant also allowed them to buy a power washer to educate boaters about invasive species prevention. Michigan boating laws require boaters to drain bilges, ballast tanks and live wells, and be sure that boats and trailers are free of aquatic organisms, including plants and debris. Leaving boats and trailers to dry for five days before putting them back into a lake is also enough to kill invasives, according to state guidelines.

“When we’re speaking to boaters, sometimes they may feel that they’re not making a difference by cleaning their boats and draining them,” Solberg said during an education session at Dodge Lake on July 6. “But if everyone contributes to that effort, it can really make a difference.”

Dodge and Island lakes aren’t the only lakes in Schoolcraft County that are infested with invasive species. Steuben Lake has had Eurasian watermilfoil for over a decade, Solberg said.

POA member Dwight Brady spearheaded the EWM abatement project. “While the lakes are still in pretty good shape, we know that without vigilance and annual treatments, this may not be the case five years from now,” he said. “We ask the public using these lakes to wash and dry their watercraft and motor props before and after using them at Dodge and Island lakes. This will reduce further infestation here and in other lakes. The property owners on these lakes are spending a significant amount of money to combat this invasive aquatic plant, and we hope all who use the public access will join us in this fight.”

Courtesy phooto
Sara Solberg, communications coordinator with the Schoolcraft Conservation District, Manistique, power washes a boat before it goes into Dodge Lake. The conservation district held an education day at the Dodge Lake Boat Launch July 6, demonstrating how to clean boats of invasive aquatic species so they don’t spread to other lakes. Invasive Eurasian Watermilfoil has been found in Dodge and Island Lakes. (Courtesy photo)

Courtesy photo
Aquatic Biologists, Fond du Lac, WI, employees use a blower to spread Navitrol in Dodge Lake, north of Manistique. The Dodge and Island Lake Property Owners Association took the first step in controlling invasive Eurasian Watermilfoil in the lakes. The treatment was done on June 18.