Texas Parks and Wildlife Press Release — Zebra mussels, a destructive invasive species that originated in Eurasia, have been found in Lake Belton in Central Texas.
Texas Parks and Wildlife Department Executive Director Carter Smith Wednesday signed an order adopting an emergency rule to add lakes Belton and Stillhouse Hollow, and portions of the Leon and Lampasas rivers to the list of water bodies covered by special regulations intended to control the spread of zebra mussels. Under these special regulations, boaters who drain their boats and gear will not be considered in violation of rules prohibiting possession of zebra mussels.
“The Lake Belton discovery underscores how critical it is for boaters all across Texas to get informed and involved to help stop the spread of zebra mussels,” said Brian Van Zee, TPWD Inland Fisheries regional director based in Waco. “Unfortunately, zebra mussel larvae, called veligers, are not visible to the naked eye. You could be transporting them on your boat and not even know it. This is why it’s particularly important to always Clean, Drain, and Dry your boat and gear before heading to another water body.”
A Texas Mussel Watch volunteer was looking for native mussels along the shores of Lake Belton on September 18 when she found a Giant Floater that had a small mussel attached to its shell. Suspecting that it might be a zebra mussel she reported it to the Texas Parks and Wildlife Department. The following day, TPWD confirmed that the small mussel was in fact a zebra mussel.
A follow up survey conducted by TPWD after the September 18 discovery revealed that zebra mussels are well established in Lake Belton and are found throughout the lake. In fact, three size classes of zebra mussels were found in Lake Belton indicating that they were likely introduced to the reservoir sometime in 2012.
“This is very discouraging news for a several reasons,” said Van Zee. “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.”
Also, TPWD’s monitoring of 23 other Texas reservoirs during the spring and summer revealed the possible presence of zebra mussels in two additional reservoirs: Lakes Worth and Joe Pool.
While zebra mussel DNA was detected in these two reservoirs, no adult zebra mussels or veligers have been found in either water body.
“DNA test results for both lakes were weak positives, and the fact that the presence of zebra mussels could not be confirmed by other methods means that these two lakes should be considered ‘suspect’ until further testing,” said Van Zee.
Rules, necessitating boaters to drain all water from their vessels before leaving water bodies with confirmed populations of zebra mussels, have already been instituted for Lakes Texoma, Lavon, Ray Roberts, Lewisville, Bridgeport, Eagle Mountain and Worth; parts of the Red River; parts of 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.
Persons traveling on a public roadway via the most direct route to another access point located on the same body of water are exempt from the requirement.
TPWD and a coalition of partners have sought to educate boaters to not transport these tiny mussels or their microscopic larvae. These partners include: Tarrant Regional Water District, North Texas Municipal Water District, Trinity River Authority, City of Dallas Water Utilities Department, Upper Trinity Regional Water District, Sabine River Authority, Canadian River Municipal Water Authority, San Jacinto River Authority, Brazos River Authority, City of Grapevine, City of Houston, City of Waco and Lady Bird Johnson Wildflower Center. Anyone interested in receiving a supply of informational brochures, wallet cards or posters about zebra mussels to distribute to boaters can order these online at www.texasinvasives.org/zebramussels 
Draining all water from livewells, bilges and bait buckets is crucial in efforts to slow the spread of zebra mussels, since contaminated boats are one of the primary ways this happens.
The zebra mussel is a small, non-native mussel originally found in Eurasia. It has spread throughout Europe, where it is considered to be a major environmental and industrial menace. The animal appeared in North America in the late 1980s and within 10 years had colonized all five Great Lakes and the Mississippi, Tennessee, Hudson, and Ohio River basins. Since then, they have spread to additional lakes and river systems, including some in North Texas.
Zebra mussels live and feed in many different aquatic habitats, breed prolifically, and cannot be controlled by natural predators. Adult zebra mussels colonize all types of living and non-living surfaces including boats, water-intake pipes, buoys, docks, piers, plants, and slow-moving animals such as native clams, crayfish, and turtles. The U.S. Fish and Wildlife Service estimates the potential economic impact of zebra mussels to be in the billions of dollars.
For more information on zebra mussels and how to clean, drain and dry a boat, visit http://www.texasinvasives.org/