Zebra mussels in area lakes likely to infest river systems downstream

Aug 26, 2017
Anthony Souffle
Keegan Lund, an aquatic invasive species specialist, shows zebra mussels clustered on a concrete block in Minnesota’s White Bear Lake. ANTHONY SOUFFLE/MINNEAPOLIS STAR TRIBUNE

Tiny Russian aquatic invaders have found a home in Texas and have even set up shop in several of our picturesque Hill Country lakes — Canyon, Travis and Austin.

Their movement downstream from those lakes through the Colorado and Guadalupe river systems is most likely unavoidable, according to one Central Texas expert.

“Once a reservoir gets infested with this pest, it’s going downstream. That’s inevitable, and we can’t stop that. All the downstream reservoirs on the Guadalupe and the Colorado are at risk, and it’s inevitable that zebra mussels show up there,” said Craig Bonds, chief of inland fisheries for the Texas Parks and Wildlife Department. “Plus, there are lots of native mussels that are threatened or have a tenuous existence that could be at risk from them.”

It’s believed that zebra mussels first made their way into the United States in the holds of Russian tankers traveling the Great Lakes system, from where they hopped to the Mississippi River drainage and have slowly worked their way southward on the hulls of boats and barges into various rivers.

They made their first appearance in Texas in 2009 when they were discovered in Lake Texoma. TPWD has since instituted the only real control program with its “Clean Drain Dry” public information pleas for boaters and anglers to clean their boats, live wells and anchor ropes, to drain them and then to dry their boats and equipment before moving any vessel to another lake in Texas.

“They will attach themselves to docks and pilings, rocks, concrete and limestone bluffs,” Bonds said. “Anything that’s hard.”

Once attached to pilings and other structures, the tiny mussels pose a threat to swimmers and even pets trying to use the pilings to exit the water or as a handhold.

“Zebra mussels do well in the Hill Country because the lakes tend to be deeper and have clear water with high calcium content,” said Monica McGarrity, an invasive species specialist with TPWD. “They need lots of calcium to make their shells.”

McGarrity did say that saltwater would present a barrier the mussels can’t breach once they’ve finished their inevitable trips down Texas rivers to the Gulf of Mexico. And only carelessness or ignorance on the part of boat owners helps them move laterally from river to river or upward on any river drainage.

One place to which zebra mussels are attracted is any water intake location, whether for power plants, drinking water treatment plants or irrigation pipes. Property owns should be aware of that tendency and monitor any pipes they may have in area rivers and lakes.