TPWD News Release — June 20, 2013
AUSTIN – Less than a year following the discovery that zebra mussels had established a population in Lake Ray Roberts, the destructive invasive species has been confirmed in Lewisville Lake by the United States Geological Survey (USGS). This is the third lake in Texas, and the second within the Trinity River basin, where zebra mussels have been discovered.
Christopher Churchill, a biologist with the USGS who has been monitoring for zebra mussels in North Texas rivers and reservoirs, discovered the live juvenile on a settlement sampler near the dam.
Churchill indicated that this latest infestation is likely the result of contaminated boats being transported to Lewisville Lake, but it could be the result of downstream transport of zebra mussels from Lake Ray Roberts via Elm Fork of the Trinity River. Also, this latest infestation appears to be relatively new as no additional specimens have been documented.
The USGS, Texas Parks and Wildlife Department, University of Texas-Arlington and others continue to closely monitor for the spread of zebra mussels in Texas.
Zebra mussels can have economic and recreational impacts in Texas reservoirs. They can clog public-water intake pipes, harm boats and motors left in infested waters by covering boat hulls and clogging water-cooling systems, annoy boat-dock owners by completely covering anything left under water and can make water recreation hazardous because of their razor-sharp edges.
With Lewisville Lake being such a popular boating destination there is a heightened risk of zebra mussels being transported to non-infested lakes by boaters. However, the spread can be slowed by making sure boats that operate in zebra mussel-infested waters are not used in any other body of water until they have been cleaned, drained and dried. In addition, TPWD adopted rules regarding the transfer of zebra mussel larvae in water from lakes Texoma, Lavon, Ray Roberts and Lewisville. To comply with these rules, boaters and anglers need to drain all water from their boats (including live wells) before leaving those lakes.
From the environmental perspective, zebra mussels are filter feeders, which mean they compete with baitfish such as shad for available forage. Any impact on baitfish in turn can affect their predators — game fish such as bass, striped bass and catfish. Zebra mussels are also very harmful to native mussel populations because they will colonize on their shells and essentially suffocate them.
TPWD Executive Director Carter Smith emphasized that the discovery underscores the importance of boaters helping to prevent the spread of zebra mussels, which can be unknowingly spread when boats and trailers are moved from lake to lake.
TPWD and a coalition of partners have been reaching out to boaters in Texas with an advertising campaign to educate them not to transport the tiny mussels or their microscopic larvae, which are invisible to the naked eye and can stay alive inside livewells, bait buckets and other parts of the boat for up to a week. These partners include: North Texas Municipal Water District, Tarrant Regional 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.
“With this somber news, I hope Texas boaters will always remember to “Clean, Drain, Dry” their boats, trailers and gear because all it takes is one instance of not properly cleaning to introduce this highly invasive and unwelcome species to a water body in Texas; and once they are established there is no known way to get rid of them,” Smith said.
Originally from the Balkans, Poland and the former Soviet Union, zebra mussels found their way to the Americas in the 1980s via ballast water of a ship. The small invaders were first found in 1988 in Lake St. Clair, Mich., and are currently known to have infested 29 states and more than 600 lakes or reservoirs in the United States.
Anyone wishing to receive a supply of informational brochures, wallet cards or posters about zebra mussels to distribute to boaters around lakes Lewisville, Ray Roberts or Texoma, please contact firstname.lastname@example.org. For more information regarding zebra mussels visit www.texasinvasives.org.