Vegetation is an important part of any aquatic system, but sometimes it can get out of control and create serious problems. All plants — whether on land or in, or around, water — photosynthesize. This means they use sunlight, carbon dioxide and water to grow and produce new plant tissue. So, aquatic plants are the basis for many beneficial elements. This makes some aquatic plant growth very desirable; however, overgrowth and infestation, especially of an undesirable species, can be disastrous.
Let’s look at some of the more common aquatic vegetation and their effects on the overall health of our waters.
Hydrilla is an exotic species of aquatic vegetation and can be difficult to identify because its appearance varies depending on the different growing conditions it is subjected to. Hydrilla at moderate densities increases the amount of fish habitat available for cover and nursing of small fish and invertebrates which also creates feeding areas for larger predators such as largemouth bass. It also provides a food source for waterfowl. The problem is that hydrilla is not easily maintained or controlled. Much like kudzu, hydrilla is very efficient at reproducing and surviving in the most adverse of conditions.
Filamentous Algae are single algae cells that form long visible chains, threads, or filaments. These filaments intertwine forming a mat that resembles cooked spinach. This algae starts growing along the bottom in shallow water or attached to structures in water (like rocks or other aquatic plants). Filamentous algae often float to the water’s surface forming large mats, which are commonly referred to as “pond scum.” There is some benefit as habitat and a food source for some fish, but it is mostly a nuisance and offers no known direct food value for wildlife.
Water Hyacinth is a non-native species and a free-floating perennial plant that can grow to a height of 3 feet. The water hyacinth has a showy spike of up to 20 light purple, blue and yellow flowers. It is a very aggressive invader and can form thick mats. If these mats cover the entire surface of a water body, they can cause oxygen depletions and fish kills. Water hyacinth should be controlled so they do not cover the entire surface of a water body.
Water Primrose is a perennial plant that stands erect along the shoreline but also forms long runners that creep across wet soil or float out across the water surface. Up to 16 feet in length, these runners form roots at their nodes. While these plants can provide feed for ducks and other waterfowl, if it grows too prolifically it can choke out other essential plants.
While this is a very limited list, it is important to identify any potential problematic aquatic vegetation and consult with experts on the best management practices for controlling undesirable aquatic species. Every body of water is different and finding the best control method is essential to maintaining a healthy fishery.
James L. Cummins is executive director of Wildlife Mississippi, a nonprofit, conservation organization founded to conserve, restore and enhance fish, wildlife and plant resources.
