Flint Lake on Valparaiso’s north side is in trouble. Invasive aquatic weeds, especially Eurasian milfoil, have become so overgrown that they’re even interfering with fish population surveys. During a recent Department of Natural Resources (DNR) survey, biologists had to stop two or three times just to clean the weeds off their boat’s propellers.

Herbicide Treatments: A Short-Term Fix with Long-Term Consequences

While treatments for Eurasian milfoil might seem like a good solution, they often come with serious environmental trade-offs. Herbicides do not actually remove the plants—they simply kill them where they grow. This leaves large amounts of decaying plant matter in the water, which can significantly reduce oxygen levels. As the plants rot, they consume oxygen that fish and other aquatic life depend on, potentially creating dead zones that are uninhabitable.

To make matters worse, the milfoil in Flint Lake is becoming more resistant to the most commonly used chemical treatments. And if the herbicide isn’t specific to milfoil, it can endanger beneficial native plants as well.

Native Plants: Critical for Young Fish and Water Quality

These native aquatic plants are more than just vegetation—they’re lifelines for young fish. “Anytime you damage these plants, you’re killing hundreds of thousands of babies,” DNR specialist said. Smaller fish use these plants to hide from predators and as feeding grounds. Destroying them reduces fish survival rates and upsets the balance of the ecosystem.

Mechanical Removal Isn’t a Silver Bullet Either

Even mechanical methods have their risks. Fragmenting Eurasian milfoil—chopping it up—can actually help it spread. Each small piece of the plant has the potential to take root and grow elsewhere in the lake.

A Call for Smarter Management

The situation at Flint Lake underscores the urgent need for responsible and effective aquatic plant management strategies. It’s not enough to kill the plants—we must remove them in a way that protects fish habitats, promotes water quality, and prevents further spread.

But maintaining that beauty, and more importantly, what’s under the water, can be challenging and at times controversial.

Lake Shawnee is one such area where Eurasian watermilfoil has flourished, leading the county to use herbicides in recent years to combat the spread of the weed.

One opponent of the herbicide use believes the introduction of herbicides to Lake Shawnee in past years has been detrimental to the bass population, and said mechanical or manual removal of excess weeds would be a better option. He also said that watermilfoil helps increase fish populations in lakes, and that some of his best fishing experiences have been at lakes where the plant grows.

Read More  https://www.cjonline.com/story/news/state/2019/08/17/lake-shawnees-use-of-herbicide-to-combat-eurasian-milfoil-draws-criticism/4437712007/

Recent research shows that the macroalgae has the potential to be the high-impact invader in Minnesota lakes that many already fear it is. It warrants the high prioritization that public agencies and many in the public are giving it.

Those are the conclusions of Carli Wagner, a graduate student with the Minnesota Aquatic Invasive Species Research Center, an interdisciplinary research center at the University of Minnesota.

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In recent years, scientists have documented countless species shifting their ranges toward the poles, higher into the mountains, and deeper into the seas in response to the changing climate.

The trend is expected to continue as the climate crisis deepens, with species that societies rely upon for a wide range of economic, cultural, and recreational value shifting their ranges to survive.

A growing number of scientists say that conservation policies based on the native-alien dichotomy could actually threaten biodiversity. Today’s climate-driven range shifts are “one of the only solutions for species to adapt to climate change,” says ecologist Nathalie Pettorelli, who studies the impact of global environmental changes on biodiversity at the Institute of Zoology in London.

Ensuring that wild species can make life-saving movements and establish self-sustaining populations in new habitats, while also protecting already-resident species, will require new ways of evaluating species — not just on their origins and historical value to society but on their ecological functions and how they can contribute to the novel ecosystems of the future.

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ProcellaCOR was recommended for use in Cocasset Lake by Joseph Onorato, an aquatic specialist with Water & Wetland LLC of Upton, which has been hired to provide treatment services by the Cocasset Lake Association.

Oronato characterized the chemical as a “miracle milfoil control solution.” This treatment would not eradicate milfoil altogether, he added, but would control the species for three years or more, during which time officials can focus on other offending plants, like fanwort, which has been identified in the privately-owned lake.

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The APA conducted monitoring and said the herbicide eliminated all traces of Eurasian Watermilfoil and found no significant impact on other plants, or degradation in wetlands. However, not every group tasked with caring for Lake George or the Adirondacks is convinced about ProcellaCOR EC yet.  There isn’t enough long-term evidence of the herbicide’s safety. Some factors have to be measured over a lot of time.

In some cases, other states have made their own observations about the effectiveness of ProcellaCOR EC and the drawbacks that could manifest. From a document on the herbicide’s use by the Wisconsin Department of Natural Resources:

“It is important to note that repeated use of herbicides with the same mode of action can lead to herbicide-resistant plants, even in aquatic plants. Certain hybrid Eurasian watermilfoil genotypes have been documented to have reduced sensitivity to aquatic herbicides. In order to reduce the risk of developing resistant genotypes, avoid using the same type of herbicides year after year, and utilize effective, integrated pest management strategies as part of any long-term control program.”

Read More https://www.news10.com/news/north-country/inside-the-herbicide-that-may-see-use-in-lake-george/

In the next several years several layers of protection will be used to thwart the arrival of the carp by way of the Chicago-area rivers and canals.

Speakers will be used to emit noise designed to turn the fish away.  If the noise won’t drive them away, then perhaps the second layer of defense, a curtain of bubbles will. And if neither are successful, an electric barrier will make up the third layer to deter the invasive carp.

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But in 2011, 5 million tons of debris was washed out to sea after the devastating tsunami hit Japan, and reached the Pacific coast of North America only one year later. This massive debris field carried a variety of glass floats, as well as docks, ships, buoys, and parts of buildings. But even more surprising was the fact that along with this debris came hundreds of living plants and animals.

Nearly 400 invasive species, from mussels and crabs to fish and seaweed, have been found on tsunami debris that has landed everywhere from Alaska to California and Hawaii. While there are public health and economic issues associated with invasive species, the deeper environmental issues include the long-term ramifications in the food web, and the ability of the environment to adapt. “The world is biologically expanding.”

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The invasive weed aggressively outgrows and outcompetes native aquatic plants. It can then clog irrigation systems and ponds, and even push out native species of fish and other aquatic life.

So far, four ponds have been treated with an aquatic herbicide to remove the Eurasian watermilfoil, but the success of the effort won’t truly be known until next growing season to see if the plant greens up.

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Primozich said according to Progressive AE, the Grand Rapids company that monitors the lake vegetation, the aquatic invasive water milfoil has now changed to the hybrid form.

“This means that it has a greater tolerance to herbicides and will require a more costly treatment than dealing with the native northern milfoil or the exotic Eurasian milfoil of the past 16 years,” Primozich said. “This appears to be a more aggressive growth pattern.”

Pentwater Lake shoreline owners (riparians) have petitioned the Pentwater Lake Improvement Board to substitute suction harvesting for the chemical treatment of floating vegetation mats for 2017.  A presentation on mechanical harvesting will be held on December 14th.

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