Aquatic invasive species on the rise in Lenawee County

A perfect summer picture for many people includes the sun shining on calm waters of a lake or pond. This picture does not include invasive plants or intruders in the water. However, more aquatic invasive species are here or moving closer to Lenawee County lakes and ponds.“Any body of water has the ability to be infected,” said Gary Marzolf, past president of the Devils and Round Lakes Preservation League. “It’s a big war we have to contend with.”The state of Michigan is known not just for her large bodies of fresh water, but also for her abundance of inland lakes and waterways. There has been concern over foreign invaders and their effect on native species for decades.The best-known invaders are aquatic creatures — zebra mussels and Asian carp. The Great Lakes were hit with zebra mussels in 1988 when they dropped out of the ballasts of foreign ships. Soon these crustaceans were attaching themselves to anything in the water and eating many plants that were the habitats of native fish.Marzolf said many people believe the zebra mussels are gone from the Irish Hills lakes. The mussels are no longer commonly seen on lake docks, according to Marzolf, because they have now moved to deeper water looking for more food.Asian carp have yet to appear in the Great Lakes, although they have been spotted in Illinois and Indiana. Marzolf and John Day, current president of the Devils and Round Lakes Preservation League, find invasive plant life is a bigger problem in Irish Hills lakes, especially Eurasian watermilfoil and starry stonewort.Plants move from one lake to another on boats. Summer volunteers don’t have the experience to encourage preventive behavior at public docks, and boaters are unaware they are moving invasive plants from lake to lake.Proper cleaning prevents infestation elsewhere. According to Marzolf, the only way to ensure a boat is completely clean is to keep it out of the water for four days, or use a bleach/water solution.Instructions for proper cleaning are posted at all public access boat launches. Tickets for improper cleaning can cost boaters up to $500.Eurasian milfoil and starry stonewort algae infestations were more noticeable last summer as higher temperatures encouraged growth and lack of rain led to lower water levels and better visibility. The shallow Irish Hills lakes have more vegetation than the larger and deeper Great Lakes, but nothing in the past compares to the current battle being fought by lake preservationists.“Weeds are weeds to most people,” Marzolf said. “It’s the misinformation out there that hurts us.”He explained that Eurasian milfoil spreads out on the top of the water like a big canopy, keeping sunlight from reaching below the surface. It can be so dense boats cannot get through.Under the canopy is a root system that travels down to the bottom of the lake, making it inefficient to just remove the floating portion. The plant also roots from cuttings, so any small pieces caught on a boat will root in the body of water where it lands.Starry stonewort is an algae that spreads underwater. “The biomass is just tremendous,” said Marzolf.This invasive species blocks the sun and uses up all the oxygen in the water, suffocating fish caught in or under the growth. One of Marzolf’s biggest fears is young divers getting trapped underneath starry stonewort.The Devils and Round Lakes Preservation League has been working diligently to find solutions to these weedy issues. Marzolf explained there is no single way to eliminate foreign invaders. The most popular method for removal has been chemical, but this creates silt which leads to a mucky lake bottom. There has been great success with use of a milfoil weevil in the battle, but some areas remain unaffected for reasons unknown. Mechanical harvest has also been successful, although it is more labor intensive and requires a diver to pull out the roots of the plants.Marzolf and Day recognized the need for a lake management plan with all Irish Hills lakes as well as other smaller bodies of fresh water in Lenawee, Hillsdale and Jackson counties. The group is hosting an informational meeting on Thursday, May 30, at 7 p.m. in the Onsted Elementary School gymnasium to explain the dangers of aquatic invasive species and discuss successful means of control of aquatic invasive species.“You need to know all your options,” Marzolf said. “We’re not in this battle by ourselves.”The Devils and Round Lakes Preservation League has found success in battle requires immediate action. The group has a rapid response unit that will come to check out any suspected invaders. Quick action while a plant is small, and complete removal, is the best way to combat invasive species.Marzolf and Day hope to find out what methods other groups and individuals are using, as well as educate those who live on or near bodies of freshwater. Panelists include people from area government offices, science experts and representatives from service companies.Anyone in the area with an interest in healthy waterways is invited to attend the meeting. The goal is to create a support network to get rid of aquatic invasive species. Questions can be submitted to and more information is available at

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