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Invasive Giant Salvinia Threatening Lake Fork in Texas

Dallas News

Texas’ Lake Fork is under threat from an invasive plant known as giant salvinia and something has to be done.

Salvinia molesta: just the scientific name seems to say it all about this invasive aquatic plant and what it may be capable of.

It first came to light in Texas in 1998, and has since spread to over 20 different lakes in the state. Texas Parks and Wildlife Department (TPWD) has now positively identified the presence of salvinia in Chaney Branch stream, west of the dam.

Two boat ramps near the outbreak site have been closed by the Sabine River Authority as a precaution, which is now in with both feet to try to control what officials are calling an alarming development.

Giant salvinia is native to South America, specifically Brazil. As is typical with many invasive, it was brought in to the country willingly, this time as fodder for the aquarium trade.

Known as one of the world’s worst free-floating aquatic weeds, it is now growing inside one of the world’s best known bass fishing impoundments: Lake Fork.

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Google Maps

To give you an idea of the famous bass lake’s value as a fishery, 257 largemouth weighing at least 13 pounds or more have been acknowledged at the lake; the next best in the state, Lake Sam Rayburn with a mere 26.

Giant salvinia is capable of doubling in size in a week causing major concern for the Sabine River Authority and the TPWD. Herbicides are being sprayed into affected areas already, and the Caddo Biocontrol Alliance is trying at this time to raise a type of weevil that is known to eat the aquatic weed.


TPWD biologist Kevin Storey said, “These plants are well established in Chaney Branch, meaning they’ve been there for months. We’ve had a lot of rain and high water this year and a lot of wind. I suspect this will affect Lake Fork for years.”

Not a rosy outlook for a body of water that brings in the amount economic influx as Lake Fork.

Herbicides and weevils aside, the greatest cause of infestation and maybe the best way to stop it is the inspection of one’s own boat after being on Lake Fork or any body of water in this or other states.

Following the TPWD’s mandate of Stop, Drain, and Dry for active boaters can do as much to stop the spread of invasives like salivinia. Environmental Officers are now ticketing those who fail to comply with the procedure to the tune of $500 fines.

If this can happen in Lake Fork, it can happen anywhere. Giant salvinia can outgrow native plants and replace them. Worse than anything they grow in dense mats that reduce oxygen levels and turn infested areas into ‘dead zones’ uninhabitable by fish. Fish like the iconic largemouth bass.


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Invasive Giant Salvinia Threatening Lake Fork in Texas