What Is Aquatic Vegetation Management?

Aquatic Vegetation

What is the best way to manage aquatic vegetation? Several methods and regulations govern these activities. The Agricultural Chemical Manual lists recommended chemicals and their rates, modes of action, and active ingredients. However, these methods are only appropriate for the state where they are applied, and they may not comply with laws and regulations outside the state. 

Floating weeds

Floating weeds are invasive plants that swim in freshwater reservoirs, lakes, and navigation canals. Unlike land plants, floating weeds are free-floating, with their leaves and roots suspended above the water surface. On the other hand, submerged weeds are rooted in the bottom and are only occasionally free-floating. Common examples of submerged weeds are water milfoil, coontail, and pondweed. Emergent weeds are usually found near shore or in shallow areas.

Some common invasive species include coontail, brittle naiad, and Eurasian watermilfoil. Each has unique characteristics, including spines. Coontail is a widespread plant, particularly in the Midwest. It is an essential weed for the Midwest, while brittle naiad is a severe invader and occurs in lakes across the U.S.


Herbicides for aquatic vegetation management include several substances. Most of these chemicals are nonselective contact herbicides that control floating and submerged vegetation. However, these chemicals are not entirely effective against watermeal. Therefore, it is essential to use only nontoxic herbicides for aquatic organisms. There are also restrictions on using these pesticides when applied to muddy or stagnant waters.

Incorrect application of herbicides can present severe risks to humans, wildlife, and fish. Following the label carefully and applying the herbicides at the correct rate is essential. Herbicides will not always remain in the water, and some herbicides may kill fish directly and deplete oxygen concentrations. Dead fish can also contaminate downstream water supplies. These contaminated waters may not be suitable for irrigation.


The DNR discourages the destruction of aquatic vegetation because it limits shoreline property values and prevents recreation. While some weeds naturally occur, excessive plant growth can cause interference with a shoreline property owner’s right to access and recreate in the water. While certain types of lakes have dense aquatic vegetation, humans are the biggest culprits of plant biomass in a lake. Specifically, nutrients from human activities can lead to the growth of aquatic weeds and other nuisance vegetation.

Fertilizers are substances that supply plants with nutrients. They are usually available in easy-to-use forms. Fertilizers are often added to the soil when planting a young plant or seedling and are continued throughout the plant’s life. The fertilizer can kill the plant if the soil is too rich in nutrients. In addition, excess fertilizer can run off into a lake or stream, creating toxic algal blooms that harm people and aquatic life.


Although you may need an aquatic vegetation management permit to remove unwanted plants, there are exceptions. Some activities, such as clearing vegetation from an area that contains aquatic plants, may not require a license, so long as you follow Best Management Practices. There are various reasons why access may not be necessary, and the best way to find out is to visit the Department of Agriculture’s website.

In addition to providing habitat and food for fish and wildlife, aquatic vegetation also helps to improve the oxygenation of the water, oxygenates the water, and improves the aesthetic value of a lake or stream. However, non-native aquatic plants can also obstruct the natural flow of a lake or pond, inhibiting dock access and main channels. So, before you start a project, make sure to apply for a permit first.

Effects on fisheries

Submerged aquatic vegetation management benefits fisheries, but its success depends on how well it’s done. The management plans in some states define the plants they’re allowed to grow and how they affect human activities. Some aquatic plants are considered weeds and must be eliminated, while others are managed for their ecological value, minimizing local economic impact and protecting the water’s ecosystem. The management strategies vary, from prevention to monitoring and suppression to control aquatic pests.

For the most part, the management of aquatic vegetation is not cheap. Herbicides must be applied to ensure the appropriate level of control. Aquatic vegetation can overwhelm all the shallow parts of a water body and negatively affect a fishery. This reduces fish numbers and quality and can disrupt predator-prey interactions. Managing aquatic vegetation is essential to keeping fish populations healthy. Managing aquatic vegetation is not a simple process; it requires collaboration between natural resource managers and scientists with fisheries expertise.


Recommended Articles

Leave a Reply