Zebra mussels have now been confirmed by the U.S. Geological Survey in Lake Lavon.
The presence of live zebra mussels or veligers, their larvae, has now been confirmed in six Texas water bodies: Lakes Texoma, Ray Roberts, Lewisville, Bridgeport, Belton, and Lavon.
A team of USGS scientists led by Dr. Christopher Churchill has been monitoring North Texas reservoirs and rivers for the presence of juvenile and adult zebra mussels as well as for the presence of zebra mussel DNA. Lake Lavon’s water samples recently tested positive for zebra mussel DNA and a veliger was also positively identified.
The USGS tests also detected zebra mussel DNA in lakes Grapevine, Fork and Tawakoni. This is the first detection of zebra mussel DNA in lakes Fork and Tawakoni. However, three consecutive surveys have detected zebra mussel DNA in Lake Grapevine making it highly suspect.
Dr. Robert McMahon, Professor Emeritus of Biology at the University of Texas at Arlington, says that while this news is of concern, he suspects that Lake Fork cannot sustain a zebra mussel population because of low levels of calcium, which the mussels use to construct their shells. He believes that Lake Tawakoni is likely more susceptible.
The finding of zebra mussel DNA in a lake does not necessarily mean that it is infested, but it may indicate that boaters are inadvertently moving zebra mussels or zebra mussel DNA from lake to lake. The USGS sample from Lake Fork was collected near the FM 17 boat ramp and the samples from Lake Tawakoni were collected near Lake Tawakoni State Park and South Shore Marina. The USGS will conduct a follow-up lake survey at Lake Lavon later this month and will resume routine sampling this spring at all areas that are currently monitored, which include lakes Texoma, Lavon, Ray Roberts, Ray Hubbard, Lewisville, Grapevine, Fork, Tawakoni and Palestine. The USGS also monitors several riverine areas including Sister Grove Creek, Elm Fork of the Trinity River, and Denton Creek.
Zebra mussels were first discovered on boats being transported from out of state to Lake Texoma in 2006. In 2009, Lake Texoma became the first lake in Texas to become infested. Zebra mussels can quickly cover boats and motors left in infested waters, clog public-water intake pipes and water-cooling systems, negatively impact aquatic ecosystems and can make water recreation hazardous because of their razor-sharp shells.
Boats are believed to be one of the main ways that zebra mussels move from one lake to another. The only way for boaters to ensure they’re not transporting zebra mussels is to always clean, drain and completely dry boats, trailers and gear after leaving a water body.
Texas Parks and Wildlife has instituted rules requiring persons leaving or approaching public water in 17 Northeast Texas counties to drain all water from their vessels and on-board receptacles. This applies to all types and sizes of boats whether powered or not, personal watercraft, sailboats or any other vessel used to travel on public waters. A proposal to extend the regulation to 30 additional counties in North and Central Texas will be considered by the Texas Parks and Wildlife Commission at its Thursday meeting. Information about the proposed change and a form for online public comment until 5 p.m. Tuesday may be found at http://www.tpwd.state.tx.us/
Under the current rules in the 17 counties, live fish cannot be transported in water that comes from the water body where they were caught and personally caught live bait can be used only in the water body where it was caught.
TPWD and a coalition of partners are working to slow the spread of zebra mussels by reminding boaters to Clean, Drain and Dry their vessels before traveling from one lake to another. The partners in this effort include: North Texas Municipal Water District, Tarrant Regional Water District, City of Dallas Water Utilities Department, Trinity River Authority, San Jacinto River Authority, Sabine River Authority, Brazos River Authority, City of Waco, Guadalupe-Blanco River Authority, Lower Colorado River Authority, Upper Trinity Regional Water District, Canadian River Municipal Water Authority, City of Grapevine, City of Houston, and the Lady Bird Johnson Wildflower Center.
For more information regarding zebra mussels, visit www.texasinvasives.org/