Giant salvinia, an extremely invasive floating aquatic fern from southeastern Brazil, was found on Caddo Lake by a Louisiana research biologist in 2006. It spread to the Texas side of Caddo by summer 2007. In 2013 the plant occupied over 5000 acres on the Tx. side of the lake alone.
Giant salvinia was first found in Texas in 1998. It has since become established in several major reservoirs and numerous private ponds. Often called “ the world’s worst weed,” giant salvinia has been responsible for substantial economic and environmental hardship in Asia, South Africa, Australia and the South Pacific.
Giant salvinia can negatively impact aquatic habitat wherever it occurs. Under ideal conditions, populations can double every five to eight days, are resistant to cold weather and can survive for weeks out of water if kept moist. Once established, the fern forms dense mats that eliminate all other aquatic vegetation in the area, eliminating even phytoplankton and zooplankton, which are vital to healthy fish populations.
Giant salvinia is easily spread over land to new locations by boat trailers, propellers or even the intakes of jet-skis. Anglers and other resource users can help by inspecting and cleaning their boats, trailer, jet-ski intakes and other equipment of all aquatic vegetation before leaving an infected area. Most new infestations of invasive species occur at or near boat ramps. Anglers fishing Caddo Lake should be aware of any suspicious floating aquatic vegetation, particularly around boat ramps and the backs of nearby creeks.
Possession or transport of giant salvinia is prohibited by state and federal law. Any possible sightings of giant salvinia on Caddo Lake should be reported to TPWD immediately. Any suspicious plants found should be left in place and their exact location documented.