The Tennessee Valley Authority (TVA) has discovered a new, invasive, fern-type, floating plant in Guntersville Lake. The plant is salvinia and this is concerning.
The TVA has found salvinia for the first time growing in Guntersville Lake. Officials are not sure if the plant will survive the winter. However, TVA is not waiting for a possible low water temperature kill so efforts are already underway to kill the salvinia. The salvinia plant species threatening Guntersville is the salvinia-molesta and salvinia-minima.
The salvinia plant spreads rapidly, and prolifically, into a monoculture that can shade out underwater natives leaving large bare bottom areas. The Tennessee Valley Authority, as mentioned, has already begun addressing the invasive plant threat. Salvinia has the potential to choke out fishable and recreational boating water.
“This is like the water hyacinth TVA found in 2019,” according to TVA officials. These officials also say they want salvinia gone, and now. Why, because salvinia can take over sections of the lake and then spread to the main lake if it makes it through the winter. This invasive plant would be very bad for fishing and recreation.
Officials at TVA are asking anglers and boaters that spot the plant on Guntersville to please report the sighting. Call 800-882-5263 between 8 a.m. and 6 p.m. Eastern (7 a.m. and 5 p.m. Central). A photo and GPS coordinates of the location would be very helpful.
Salvinia molesta is native to southeastern Brazil and northern Argentina. The plant grows year-round (with conducive temperatures) and has been found in north, central, and southwest Florida where it is quickly eradicated when found. Giant salvinia grows rapidly and produces a dense floating canopy on the surface of ponds, lakes, and rivers.
Salvinia is a long chain formation that occurs as the plants grow together to form mats. Giant salvinia is very prolific, and under favorable conditions, can double the size of its mats in 7 to 10 days. As the mats continue to grow they form thick layers of vegetation. Overseas, the layers have grown more than 2 feet thick.
This invasive plant would be very bad for fishing and recreation.
This species is a floating aquatic fern that thrives in slow-moving, nutrient-rich, warm, freshwater. It spreads aggressively by vegetative fragments. Salvinia is dispersed long distances within a body of water (via water currents) and between bodies of water (via animals, contaminated equipment, and boats or vehicles). The plant may also be cultivated by aquarium and pond owners and is sometimes released by flooding or intentional dumping.
The salvinia molesta’s dense vegetation mats reduce water-flow and lowers the light and oxygen levels in the water. This stagnant, dark environment negatively affects the biodiversity and abundance of freshwater species including fish and submerged aquatic plants. Invasions can alter wetland ecosystems and cause wetland habitat loss. Salvinia invasions also pose a severe threat to socio-economic activities dependent on open, flowing, and/or high-quality bodies of water, including hydro-electricity generation, fishing, and boat transport.
The free-floating fern stems are rootless, hairy, about 10 cm. long. Salvinia exhibits great variations in form and structure depending on habitat conditions such as space and nutrient availability.
Leaves are borne in threes and appear 2-ranked, but with a 3rd leaf finely dissected and dangling, resembling roots. The third leaves are rounded to somewhat broadly elliptical to 2 cm long, with a cordate base. The upper surface exhibits 4-pronged hairs joined at the tips (resembling an egg beater). The lower surface is also hairy.
The plant spores appear as a nutlike sporocarp (a multicellular structure), that trails beneath.
• Giant salvinia grows rapidly and produces a dense floating canopy on the surface of ponds, lakes, and rivers.
• Threat to the TVA reservoir system that generates an average annual economic impact of $11.9 billion as well as more than 130,000 local jobs.
• TVA manages nuisance aquatic plants in the vicinity of developed public access areas (e.g., parks, ramps, swim beaches, and similar public facilities) valley-wide.
• Nuisance aquatic plants along private shoreline areas can be treated at the property owner’s expense by a licensed private commercial applicator in accordance with state regulations.
• TVA will assist private shoreline property owners in the identification of nuisance aquatic plants, discuss management strategies and provide contact information for state agencies that regulate and issue permits for herbicide treatments in public waters such as reservoirs.
Reference resources include TVA’s Aquatic Plant Management Specialist and Wikipedia,
University of Florida invasive plant website (https://plants.ifas.ufl.edu/plant-directory/salvinia-molesta/).