AGFC: Giant Salvinia identified in Millwood Lake tributary

INFESTED CREEK — Giant Salvinia can double in size in less than a week, choking out native vegetation and making access impossible for boats and fish. AGFC photo

By RANDY ZELLERS | Arkansas Game & Fish Commission

Arkansas Game and Fish Commission and U.S. Army Corps of Engineers crews worked tirelessly all weekend responding to the discovery of the invasive aquatic plant giant salvinia near the White Cliffs Public Use Area on the Little River, a major tributary entering Millwood Lake.

“After being called on Friday by a local angler using the ramp at the White Cliffs Campground, we sent out our rapid response team to confirm the sighting, assess the situation, and begin containing the spread,” said Matt Horton, AGFC Aquatic Nuisance Species Coordinator. “We initially contained a 300-foot section of shoreline at the campground where the infestation likely originated. However, subsequent surveys found the plant had spread, and we expanded containment booms to cover 1,900 feet of shoreline around the boat ramp.”

AGFC and USACE personnel physically removed as much salvinia as possible near the campground and ramp, hauling more than 900 pounds of the invasive plant to dry ground for proper disposal.

“USACE has been a tremendous partner throughout the weekend,” Horton said. “They had at least four staff members working alongside our team to search for and collect the plant since Friday’s discovery.”

Crews have found fragments of giant salvinia up to a mile both upstream and downstream from the campground, and containment efforts will continue throughout the week.

“The primary challenge with giant salvinia is that even a tiny fragment can reproduce and survive, and the shoreline along the Little River is dense with vegetation where fragments easily hide,” Horton said. “We will begin applying an EPA-approved aquatic herbicide this week to target visible salvinia and knock back the cutgrass and shoreline vegetation harboring it. Once that vegetation dies down, we will coordinate with USACE to conduct a controlled burn to eliminate any fragments trapped in the dead plant mats.”

Millwood Lake Operations Project Manager Tiffany Smith said the USACE is dedicated to fighting the infestation for the sake of the fishery as well as recreation and water supply needs provided by Millwood Lake.

“We’re grateful for the quick response and partnership with AGFC” said Millwood Lake Operations Project Manager Tiffany Smith. “If it goes unchecked giant salvinia poses a threat to Millwood Lake’s environmental stewardship, recreation, and water supply missions.”

Officials urge boaters and anglers to avoid disturbing the floating containment booms. Anyone who suspects they have spotted giant salvinia in Millwood Lake or nearby waters should contact the AGFC Southwest Regional Office at 501-255-1496, email katie.thomsen@agfc.ar.gov, or submit an online report at agfc.com/ans.

This is not the first occurrence of giant salvinia at Millwood Lake; the species was detected and eradicated there in 2020. However, biologists stress that outdoor recreationists must remain vigilant.

“We were able to stop it back then because of an early detection and immediate response like this one; hopefully we’ll be able to fight it back again, but we need the public’s help,” Horton said. “Texas and Louisiana spend millions of dollars annually trying to manage giant salvinia, and we are actively fighting infestations in two other south Arkansas lakes — Lake Columbia and Lake Erling,” Horton said. “With low seasonal water levels, anglers and hunters frequently travel between different waterbodies, which increases the risk of inadvertently transporting invasive species. It is vital to clean, drain, and dry boats, trailers, and gear between every outing.”

Boaters and waterfowl hunters can prevent the spread of aquatic nuisance species by following three basic steps:

• Clean: Inspect and remove all visible mud, plants, and seeds from trucks, trailers, boats, waders, decoys, and blinds. Wash equipment thoroughly with a high-pressure sprayer.
• Drain: Pull all boat drain plugs, livewell valves, and bilge lines before leaving the boat ramp area.
• Dry: Allow all equipment to dry completely for at least five days before launching into a different body of water. If five days is not feasible, thoroughly towel-dry all wet surfaces.