TEXARKANA, Texas - Cold winter weather killed most of the giant salvinia in Bringle Lake, but a Texas Parks and Wildlife Department crew saw new growth of the invasive species there last week and herbicide application has resumed.
Winter freezes killed about 90% of the salvinia that was left in Bringle Lake after a series of herbicide treatments in the fall, said John Findeisen, leader of TPWD's Aquatic Habitat Enhancement Team. But the plant is so resilient new growth has begun as weather warms.
Overall the battle to stop the plant's spread has been going well since it began last summer.
"We're getting ahead, and we're staying ahead," though the plant's total eradication from the lake likely will never be achieved, Findeisen said.
The main salvinia patch on the lake was about 9 to 10 acres in size but now covers less than an acre, said Robby Robertson, Texas-side Parks and Recreation Department director.
"We're really controlling it very well. I'm pretty optimistic that it's not going to take over the lake," he said.
Herbicide spraying will continue in April and periodically thereafter.
Calling the free-floating fern "one of the major threats to aquatic ecosystems in Texas," TPWD announced last June that giant salvinia had been found in Bringle Lake, the centerpiece among a group of parks and trails in the northern part of the city. Vigilant residents first alerted local officials to the problem.
"Our local fishermen and people that enjoy the lake are really the ones that brought this to our attention to begin with. The fact that we had some really good citizens saying, 'Hey, we need to do something about this,' and we were able to work with Texas Parks and Wildlife, that is the reason I think we were able to get on top of it before it did get too out of hand," Robertson said.
Under ideal conditions, giant salvinia can double in size in less than a week. It forms thick mats of foliage on the surfaces of bodies of water, preventing light and oxygen from reaching any animals or other plant life beneath. The result is an aquatic desert where nothing else can live.
Left unchecked, giant salvinia also prevents water recreation, making fishing, boating and swimming impossible. The problem is most common in East Texas north of Houston.
TPWD urges anglers and other boaters to thoroughly clean, drain and dry their boats and other equipment after use to prevent spreading giant salvinia - and other invasive species such as zebra mussels - from one body of water to another. Hunters, too, should follow "clean, drain and dry" protocols, as invasive species can be spread by gear such as duck decoys, Findeisen said.
Transporting prohibited invasive species in Texas is illegal and punishable with a fine. Boaters are also required to drain all water from their boats and onboard receptacles, including bait buckets, before leaving or approaching a body of freshwater.
(For more information on how to properly clean, drain and dry boats and equipment, visit the TPWD YouTube channel for a short instructional video. To learn more about common and giant salvinia along with other invasive species in Texas, visit tpwd.texas. gov/landwater/stop-invasives/. The department recommends that Texans who have frequent contact with bodies of water should learn to identify invasive species, and if they spot any they should report the sighting to TPWD at 409-698-9121, Ext. 235, or by emailing photos and location information to [email protected].)