Lake Bistineau has nearly hit its mark with this year’s drawdown.
As of Friday afternoon, the lake is about 6.7 feet below pool stage. Jeff Sibley, biologist supervisor for inland fisheries division I, said the battle against giant salvinia has knocked it back to roughly 750 to 800 acres on the lake.
Giant salvinia is an invasive aquatic weed native to Brazil. LDWF officials say it is on every body of water they take care of, but they spend the most money to combat the weed on Lake Bistineau. Salvinia reproduces at a rapid rate, covering areas within only three to five days.
“Efforts to further reduce the salvinia are ongoing, including herbicide applications and the addition of salvinia weevils,” Sibley said.
The drawdown began earlier this year due to a last minute political decision to push the drawdown back in 2016. On May 1, the date the drawdown began, an estimated 3,742 acres of salvinia covered the lake. Sibley said that number has been reduced by approximately 3,000 acres.
“There is an estimated 10,000 acres of water remaining in the lake that can be accessed from four public boating access points,” he said, naming the boating launches: Grices, Port O’Bistineau, the Webster Parish Public Ramp and the Bossier Parish Public Ramp.
Last year, the drawdown was pushed back from its planned date of mid-July to approximately mid-August. LDWF officials said the salvinia was worse this year and had to begin the drawdown on May 1 to combat the large amount of salvinia that had grown over the past year.
LDWF has also been spraying the salvinia with herbicides to knock it back as well as using the drawdown to dry it out.
Sibley said they hope to see more drying action in the coming weeks to knock it back even further.
Weevils have also been introduced to the lake by wildlife and fisheries officials in the hopes these weevils will survive the winter. Sibley said the weevils they’ve had this year appear to be promising in that they have survived two very mild winters. The idea now is to see if they will continue to survive in enough numbers to help even further control the growth of the salvinia.
The weevils are salvinia’s only known natural enemy.