Gaint Salvinia: This time… It’s Personal!

A Staff Encounter With an Invasive Species


A volunteer pulls giant salvinia out of Bayou St. John in late winter 2019.

Lurking beneath the floating dock at the New Canal Lighthouse, a vindictive swamp monster plans its next attack. The creature lacks sharp claws, a nervous system or any cognitive ability, yet it manages to slowly choke its victims. Its mere presence strikes fear in the hearts of those who care about the safety and health of Lake Pontchartrain.

What is this terrifying aquatic organism? Is it a shark? An alligator gar? Some form of lethal bacteria? No, no and no. It’s even worse than those things. The monstrous organism hiding under the dock is none other than giant salvinia. DUNH…DUNH… DUNH!

Giant salvinia is an invasive species native to southeastern Brazil. The species was most likely introduced to Louisiana via ornamental plant trade. Giant salvinia reproduces quickly forming dense mats that clog waterways, limit recreation, and block native flora from receiving sunlight. The watery menace has sunken to a new low by ensnaring the New Canal Lighthouse’s recently constructed floating dock. Education coordinator, Laine Farber has taken this invasion as a personal attack.

“I really enjoy siting on the dock during my break time, Laine said. “It is far less pleasant when covered in dead vegetation and the bits of trash that got caught in the salvinia." The lighthouse staff set out to remedy the problem by removing the debris from the dock. Laine volunteered as tribute to fight the swamp monster. Laine approached her foe with weapons of small-scale destruction: a shovel, a dip net, a push broom and a bunch of buckets. After an hour of scrubbing, scooping, shoveling and snaring, Laine had vanquished the beast. Or so she thought.

“When I returned a few days later, the dock was covered again,” Laine said.

PC Outreach Coordinator, Briana Cervantes, also attempted to remove salvinia from our grounds, only to see it return days later. When asked for a quote about the experience Briana simply said, “¯\_(ツ)_/¯.” The problem is that Giant salvinia reproduces vegetatively, meaning the branches that break off form new plants. And let me tell you, these ferns break apart easily. While at first,  cleanup efforts felt futile, it was soon realized that they weren’t complete failures. Though the dock and deck were covered again, PC staff made an impact by manual removing salvinia from their waterways. Manual removal of salvinia is one of the most effective ways to combat an invasion of the species. Other effective methods of removal include using biological controls such as the top consumer of giant salvinia the salvinia weevil and chemical solutions such as the introduction of herbicides.