Zebra mussels on a break but they’ll be back, expert warns
Female zebra mussels can produce up to 1 million eggs a year, quickly rebuilding populations laid low by hot temperatures, drought, and overpopulation.
The good news is that, for the moment, zebra mussels appear to have disappeared from the Highland Lakes. The bad news is, although they’re in a down cycle, they’re still lurking in local waters and will most likely make a comeback in the spring.
“Zebra mussels have boom-and-bust cycles with some years higher and some lower,” said Monica McGarrity, senior scientist for aquatic invasive species at the Texas Parks and Wildlife Department. “Once they are introduced, they are there to stay. There’s no effective way to eradicate zebra mussels once they are fully established in a lake.”
The invasive species was first discovered in the Highland Lakes in 2017, when they were confirmed by the TPWD to have infested Lake Travis. They have since spread to lakes Marble Falls, LBJ, Inks, and Buchanan. This past spring, their plaguing presence spawned a few small businesses devoted to removing zebra mussels from boats, docks, ramps, and retaining walls.
While it might look like these entrepreneurs have scraped themselves out of business, they are just on a seasonal break, which could last a few years — or not.
In three to five years, zebra mussels can overpopulate, causing them to die off until conditions improve and they begin to regenerate. It can take another three to five years for them to grow back into the next boom cycle. Boom-and-bust cycles depend on food sources as well as temperatures and drought conditions.
“Even if you don’t see zebra mussels on the surface, they are in the water below,” McGarrity said. “They can’t survive out of water, so the lower lake levels and high temperatures have caused them to die off pretty quickly. But they are still in the cooler areas of the lake.”
Each female can lay up to 1 million eggs a year, so when favorable conditions return, it won’t take long for zebra mussels to make a comeback.
Boats should be kept clean and stored on lifts out of the water. Following TPWD protocol for cleaning and moving boats helps prevent the spread of the invasive mussels. It’s also the law.