Texas Parks and Wildlife Department biologists have confirmed that Lake Georgetown in Williamson County is “fully infested” with zebra mussels after finding an established, reproducing population of the invasive species during testing in late October and early November.
Zebra mussels — which have been known to clog pipes and machinery, causing billion of dollars in damage in lakes around the country — already had been spotted this summer in the Highland Lakes — Lake Travis in June and Lake Austin in August.
Authorities said biologists found zebra mussel larvae in Lake Georgetown during routine water sampling Oct. 27 and discovered young, settled mussels along the lake’s shoreline Nov. 6.
“This is very unfortunate news because as recently as spring 2017 all routine plankton samples have tested negative for zebra mussel larvae and we hadn’t found any juveniles or adults,” said Brian Van Zee, regional director of inland fisheries for Texas Parks and Wildlife. “It just goes to show how rapidly zebra mussels can colonize and establish themselves in our lakes once they are introduced.”
Lake Georgetown, a 1,297-acre body of water just northwest of Georgetown on the North Fork of the San Gabriel River, is controlled by the U.S. Army Corps of Engineers. State fisheries biologists plan to work with the Corps and the Brazos River Authority to put up warning signs and watch for the potential spread of zebra mussels — particularly downstream at Granger Lake.
Authorities on Monday also announced that a fourth Texas reservoir this year, 90,000-acre Lake Livingston north of Houston on the Trinity River, has been classified as infested. Livingston had been classified as “positive” with multiple detections of zebra mussels.
The statewide total of zebra mussel-infested lakes is 13.
“Boaters can help slow the spread of zebra mussels by taking the proper steps to clean, drain and dry all boating equipment before leaving the boat ramp,” Van Zee said.
Texas law prohibits the possession or transportation of zebra mussels, dead or alive. Boaters are required to drain all water from their boat (powered or unpowered) and onboard receptacles before leaving or approaching a body of fresh water, Parks and Wildlife officials said.
State parks officials said zebra mussels can cover shoreline rocks and litter beaches with sharp shells, clog public-water intakes, and damage boats and motors left in infested waters.
The small, razor-sharp invasive species with origins in eastern Europe has been spreading across the United States since 1988, when the first established population was found between Lake Huron and Lake Erie, according to the U.S. Fish and Wildlife Service.
A report produced by the Idaho Aquatic Nuisance Species Task Force in 2009 said congressional researchers found that zebra mussels clogging industrial pipes in the Great Lakes cost the power industry there about $3.1 billion from 1993 through 1999. Costs from other affected industries in the area totaled roughly $5 billion, the report said.
It took more than two decades, but in 2009, the first zebra mussels in Texas were found on Lake Texoma. Other Texas lakes with mussel infestations include Lake Belton, Canyon Lake, Lewisville Lake, Eagle Mountain Lake and Lake Bridgeport.