The Texas Parks and Wildlife Department announced Monday that reproducing populations of zebra mussels have been found in Lake Lyndon B. Johnson and Lake Pflugerville – bringing the total number of statewide lakes infested with the invasive species to 17.
In Central Texas, reproducing populations of the mussels have infested lakes Austin, Belton, Canyon, Georgetown, Lady Bird, LBJ, Pflugerville, Stillhouse Hollow and Travis. Biologists have also found larval mussels in Central Texas at lakes Dunlap, Granger, Placid and Walter E. Long, also known as Decker Lake.
The parks department classifies zebra mussels as invasive because of their ability to aggressively siphon nutrients in waterways and kill native plant matter, and because their sharp, fingernail-sized shells can harm unsuspecting swimmers.
The department said the presence of zebra mussels in Lake LBJ, near Horseshoe Bay, suggests the invasive species will likely spread to Lake Marble Falls. Monica McGarrity, a senior researcher for the department's aquatic invasive species management program, said the mussels will likely spread throughout the Highland Lakes, the chain of lakes that supply Austin's water.
"It is disheartening to see zebra mussels spreading higher up the chain of the Highland Lakes in the Colorado River basin," she said. "Only boats can move this invasive species upstream to uninvaded reservoirs and downstream dispersal is inevitable."
The fact that the mussels headed upstream, McGarrity said, means Inks and Buchannan lakes, which are farther up the Highland Lakes chain, could also see populations of zebra mussels soon.
The invasive mollusks were first found in Lake Texoma in 2009.
Austinites will remember zebra mussels for their ability to clog water intake pipes.
The mollusks did just that earlier this year, clogging pipes at the Ullrich Water Treatment Plant on the Colorado River and making Austin's water smell.