Invasive Weeds and Herbicides Are Threatening Fish in Flint Lake
Flint Lake in Valparaiso, Indiana, is struggling with invasive Eurasian milfoil — a fast-spreading aquatic weed that’s clogging waterways and harming fish populations. While herbicides are often used to control the problem, they can create oxygen-depleting decay zones and destroy vital native plants that young fish rely on for shelter and food.
The lake’s challenges highlight the need for smarter, more sustainable management methods that control weeds without compromising aquatic ecosystems.
Read the full article on our website: Invasive Weeds and Herbicides Are Threatening Fish in Flint Lake
Posted on May 6, 2025, in Aquatic Herbicides, Aquatic Plant Managemetn, invasive species and tagged Aquatic Herbicides, aquatic invasive species, aquatic plant removal, biodiversity, Eurasian milfoil, herbicide resistance in lakes, invasive species, invasive species management, mechanical weed harvesting. Bookmark the permalink. 1 Comment.
Aquarius Systems 
There is a common misperception that weed harvesters are responsible for the spread of Eurasian milfoil. It is perpetuated by a variety of sources. People often accuse the weed harvester for causing “floaters” long before it has been launched into the lake! But what are some real causes of milfoil spread?
– Auto fragmentation: A natural way Eurasian milfoil reproduces
– Herbicide use: The collapsing vegetation breaks apart and washes up on shore.
– Any disturbance that is caused by waterfowl, swimmers, boat trailers, pets, jet skis, fishing, other wildlife; and even the fish themselves!
– 200+ boats over a two-day weekend versus one harvester working 5 days a week: What’s the biggest culprit here?
One medium sized weed harvester can remove from 4,000 to 12,000 pounds per hour of Eurasian milfoil which, left on its own, would be chopped up by boat propellers, auto fragmented, or otherwise spread around the lake. In other words, the harvester can remove a massive amount of biomass that would otherwise be fragmented and spread.
An added bonus is that the nitrogen and phosphorus that is bound in the vegetation is also removed from the lake by the harvester.