AUSTIN —The Texas Parks and Wildlife Department (TPWD) has confirmed the presence of invasive giant salvinia at three locations on Lake Fork – the largest total infestation ever found on the lake.

Personnel from the Sabine River Authority (SRA) and the Tyler North district fisheries office confirmed the infestation Thursday, Oct. 26, within hours of being notified by a local property owner. The TPWD Brookeland aquatic invasive species team later coordinated the placement of a containment boom to isolate the worst-affected cove and surveyed sections of shoreline to determine the extent of the giant salvinia’s presence.

“We are seeing 12-15 total acres of giant salvinia in Lake Fork at this time,” said John Findeisen, Brookeland Aquatic Invasive Species team lead. “There’s enough giant salvinia scattered throughout the lake that eradication would be almost impossible at this point. We will continue to search the lake but we also ask that boaters and property owners also keep an eye out for the plant and call us if they see it.”

According to Findeisen, 90 percent of the infestation – about 10 acres – is confined to White Oak Creek behind the containment boom. But the other scattered plants confirmed along the highway 17 bridge at Fisherman’s Cove Boat Ramp, and directly across from White Oak Creek cannot be contained to their current locations.

Judging by the distribution and age of the plants, it is apparent the giant salvinia at White Oak Creek has been in place for at least 8-10 months, Findeisen said. As is the case for other introductions in East Texas, the plants were most likely introduced to the lake by boat trailer.

“These new infestations underscore the importance of removing all plant material from boats and trailers before leaving the ramp,” Findeisen said. “Invasive species spread quickly and easily so we urge all boaters to clean, drain, and dry their equipment to keep the giant salvinia from spreading to other East Texas lakes.”

In addition to placing the containment boom around the White Oak Creek infestation, TPWD staff will be conducting chemical treatment on the other giant salvinia mats. Because the giant salvinia cannot be contained and will only be maintained at the lake, TPWD will not be treating the giant salvinia patches currently mixed in with native emergent plants.

“When with other vegetation, giant salvinia can be tricky to treat with herbicides.” Findeisen said. “Our experience with treating salvinia in mixed plant colonies has been the salvinia rebounds faster after the treatment and is no longer being held in place by the other plant species. This gives the giant salvinia free rein to float all over the lake, creating a bigger problem. Additionally, we don’t want to disrupt the habitat those native plants provide to fish and wildlife.”

TPWD and SRA will continue to conduct additional surveys to check for the spread of the plant to other areas of the lake, and additional chemical treatment will be conducted on giant salvinia mats as needed, Findeisen added.

Giant salvinia has been present in Texas for nearly 20 years. Giant salvinia was first discovered on Toledo Bend in 1998 and has since spread throughout East Texas. In addition to current infestations at Toledo Bend, Sam Rayburn and Caddo Lake, the invasive plant has been newly introduced or reintroduced at four Texas lakes in the last three months: Lake Murvaul, Lake Palestine, Martin Creek Lake and now Lake Fork.

All boaters should learn to identify giant salvinia as well as other invasive species that occur in Texas waters. Most importantly, boaters should remember to clean their boats and trailers before leaving the boat ramp. Transporting giant salvinia, along with other invasive species, is prohibited by law and punishable by a fine of up to $500 per violation.

Boaters and property owners are urged to clean, drain, and dry their boats and trailers in between trips and to report additional infestations outside of the affected areas by calling (903) 593-5077, (903) 570-5745, or by emailing kevin.storey@tpwd.texas.gov.

The Lake Fork Sportsman’s Association (LFSA) is hosting a public meeting to discuss TPWD’s management of invasive species in Lake Fork. The meeting will be held at 6 p.m. Tuesday, Nov. 21, at the Emory City Center at 735 N. Texas Street. TPWD staff will be on hand to discuss treatment strategies and future plans and personnel from SRA will be in attendance to provide support. To add balance to the meeting, LFSA members will discuss their efforts to reintroduce native plants into Lake Fork to improve aquatic habitat.

For more information on giant salvinia and other invasive species, visit tpwd.texas.gov/giantsalvinia.