Texas Parks and Wildlife Department biologists have classified Lake Georgetown as infested with an established, reproducing population of invasive zebra mussels and have also changed the status of Lake Livingston to fully infested.
Lake Georgetown is a 1,297-acre impoundment controlled by the U.S. Army Corps of Engineers, located just north of Austin on the North Fork of the San Gabriel River. Lake Georgetown’s infestation was confirmed by TPWD biologists after discovering larvae in routine water samples Oct. 27. A follow-up survey conducted by the Brazos River Authority and TPWD district fisheries biologists Nov. 6 also revealed young settled zebra mussels attached to rocks along the shoreline.
“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, TPWD inland fisheries regional director. “It just goes to show how rapidly zebra mussels can colonize and establish themselves in our lakes once they are introduced.”
Lake Livingston is a 90,000-acre reservoir controlled by the Trinity River Authority, located just north of Houston on the Trinity River. Previously classified as positive with multiple detections of zebra mussels, Lake Livingston has now been upgraded to the infested classification after ongoing research conducted by Dr. Christopher Churchill of the U.S. Geological Survey confirmed that zebra mussels have developed a reproducing population in the lake.
In 2017, four Texas reservoirs have become infested with zebra mussels, bringing the statewide total to 13 infested lakes.
“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.
At Lake Georgetown, TPWD fisheries biologists will continue to work with the Brazos River Authority and U.S. Army Corps of Engineers to establish signage, monitor the spread of zebra mussels in the reservoir and monitor for early detection of zebra mussels at downstream Granger Lake.
Boaters and property owners at all affected and nearby lakes are encouraged to keep an eye out and report any zebra mussel sightings to TPWD.
The rapidly reproducing zebra mussels, originally from Eurasia, can have serious economic, recreational and environmental impacts on Texas reservoirs and rivers. Zebra mussels can cover shoreline rocks and litter beaches with sharp shells, clog water intakes, damage or increase maintenance on hydroelectric and other facilities using raw surface water, and damage boats and motors left in infested waters.
In Texas, it is unlawful to possess or transport zebra mussels, dead or alive. Boaters are required to drain all water from their boat and onboard receptacles before leaving or approaching a body of fresh water in order to prevent the transfer of zebra mussels. Zebra mussel larvae are microscopic and both adults and larvae can survive for days in or on boats transported from a lake, especially during cooler fall months. The requirement to drain applies to all types and sizes of boats whether powered or not: personal watercraft, sailboats, kayaks/canoes or any other vessel used on public waters.
More information about zebra mussels can be found online at tpwd.texas.gov/ZebraMussels.