With the news that zebra mussels have been found recently in Belton Lake reservoir near Temple, Central Texas lakes such as Austin, Canyon and Travis appear to be right in the path of the destructive creatures imported from Asia.
“The environmental conditions, the water chemistry and water temperatures, appear to be conducive to zebra mussels in those lakes,” says Brian Van Zee, Texas Parks and Wildlife’s regional fisheries director in Waco. “And once they’re established, there’s no way of getting them out of a lake.”
Van Zee says that state efforts to halt the zebra mussel advance are focused on anglers and boaters who travel from one body of water to another.
Boat owners can spread the mussels by transporting lake water containing their larvae, known as veligers, or by carrying the mussels themselves on trailers or boat hulls.
Van Zee says state “clean, drain, dry” rules regarding boat transit can help stop the spread of invasive aquatic species such as zebra mussels., which are small and innocuous until they begin to colonize lake areas.
The mussels are believed to have come to this country in ballast tanks of foreign ships working in the Great Lakes. After colonizing the Great Lakes, they began moving south along the Mississippi, Tennessee and Ohio waterways. They were first documented in Texas in 2009 in Lake Texoma on the Oklahoma-Texas border and have been spreading southward since, Van Zee says.
Not only do the mussels form huge colonies in lakes, they can clog water intake points for municipalities and threaten native mussel populations. They will attach themselves to crayfish and turtles, as well.
TPWD imposed the “clean, drain, dry” rules for lakes with confirmed zebra mussel populations. Those lakes include Texoma, Lavon, Ray Roberts, Lewisville, Bridgeport, Eagle Mountain and Worth. Also on the watch list are parts of the Red River and the Elm Fork of the Trinity River and all impounded and tributary waters of the West Fork of the Trinity River above the Lake Worth dam, Van Zee reported in a TPWD news release.
According to TPWD reports, the zebra mussel in Belton Lake was discovered by a volunteer searching for native mussels in mid-September. The volunteer found one suspicious mussel that was confirmed as a zebra mussel and later tests found that the invasives are established throughout the lake, Van Zee says.
Researchers found different size and age classes of the mussels, as well, which means the invasion there probably began sometime in 2012.
“This is very discouraging news for a several reasons,” Van Zee announced. “Not only does this mark the first time that zebra mussels have been documented in the Brazos River basin, this new infestation is nearly 200 miles south of where zebra mussels are currently found in Texas. Unfortunately, this means that lakes in the central portion of the state are at even greater risk.”
Sadly, we’re almost certain to find zebra mussels sooner or later throughout Central Texas. There are a number of local fishing tournaments on Belton Lake and anglers there routinely travel to tournaments on other lakes. Boats that are docked in slips and sitting in the water for long periods of time are even more likely to have mussels attached. If those boaters don’t follow state protocol, the mussels will be able to continue to move to other lakes.
Some lakes in far East Texas may have a natural protection because of the pH of the water there. “Their water is really soft and that seems to help. They probably won’t be susceptible,” he says. Harder water lakes such as we have in Central Texas aren’t so lucky.
Van Zee says a bigger challenge than mussel movement by boat is mussel movement through naturally flowing waterways. “… we can’t stop a flowing river, even with a dam, and they’re going to move when the conditions are right,” he says. “I don’t know how to stop them once they’re here.”