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Prevention is the key to combating zebra mussels in Texas lakes


Clean. Drain. Dry.

Those three words are seen and repeated year-round for Texans. Clean, drain and dry. But why?

Texas Parks & Wildlife shares the message every year to prevent invasive species from taking on a new body of water. In this case, it is the well-known zebra mussel they’re trying to contain.

The zebra mussel was first documented in Texas waters in 2009, according to the United States Geological Survey. The zebra mussel, distinguished by its zebra-like markings, is an invasive species. The U.S. Fish and Wildlife Service describe the mussel as a “widespread ecological and economic threat.”

Zebra mussels are native to the Caspian and Black Seas. The first official account of the mussel entering United States waterways was in 1988 from Lake St. Clair, located between Lake Huron and Lake Erie. Within two years, zebra mussels were found in all five of the Great Lakes and soon after were found in major rivers such as the Mississippi. The United States Geological Survey said that it has since been found in over 600 lakes and reservoirs in the country.

“The problems with the zebra mussel are that they’re not native,” said Brazos River Authority Environment and Compliance Manager Tiffany Morgan. “In Texas, they can outcompete the native fauna. There are not a lot of native predators for [the zebra mussel]. They grow exponentially with very little control. We do have some species of fish that will eat them, but just not enough.”

Though zebra mussels have not been found in the three Brazos River Authority owned and operated reservoirs, they have been found in several other lakes and reservoirs throughout the state.

In Texas, the zebra mussel has been documented in 21 lakes, creeks and waterways.

The National Park Service said that zebra mussels could cause a variety of difficulties for those on the water. On an economical side, these mussels can accumulate on hard surfaces, also known as “biofouling.” For stationary docks and boats that are in the water for long periods of time, this could become an issue, as it will become encrusted with the mussel, which will make it hard to clean off.

“They have very unique physical features that allow them to attach to hard surfaces. Freshwater mussels can’t do that,” Morgan said. “[Zebra mussels] can attach to boats, water intake structures, pipelines, dam gates, anything that’s hard. They can very quickly cover a water intake structure, or get sucked up into the pipe and start to constrict the length of the pipe.”

To put it into perspective, a city finds that it needs a pipe that is 36-inches in diameter to get water to and from a location where it needs to be, in a specific amount it needs to be. If the area were to become infested with zebra mussels, that 36-inch pipe could soon slim down to only a few inches in width within a few years, which could then cause a water supply crisis.

“[An infestation] can make your infrastructure maintenance and operating expenses skyrocket, can inhibit the ability to deliver key life-sustaining requirements,” Morgan said.

Biofouling also will cause issues for the environment as well. The National Park Service said that zebra mussels can, and will, attach to native mussels just as they do to hard surfaces. Zebra mussels can also completely cover the native mussel, making it hard for the native mussel to move, feed or regulate water. Due to its quick reproduction cycle, the zebra mussel will also outcompete the native mussel for food, space and overall water system.

Zebra mussels reproduce quickly and rely on currents to spread their populations. The National Park Service said that because zebra mussels depend on this, they can only move downstream in rivers and need a ride to move upstream. Humans have often aided them in spreading, by transporting them to new places, unintentionally, on their boats. Zebra mussels reproduce by expelling up to a million microscopic veligers. Because of this, it can live in the bottom of a boat and in a motor, ready for a new home in a new body of water.

Once zebra mussels become established in a body of water, there isn’t much that can be done to remove them.

Did you know that not cleaning your boat and transporting aquatic plants to another body of water is actually unlawful?

Texas Parks and Wildlife advises that all boat owners drain water from their boat and gear before coming to and leaving a body of water. If someone were to not remove and dispose of aquatic plants or wildlife that could be harmful, such as the zebra mussel, they could be fined $500. Repeat offenders could be fined up to $2,000 and possibly spend up to 180 days in jail. This is extended to all vessels, watercraft, trailers, vehicles and other items used to transport or launch watercraft.

Here are steps that Texas Parks & Wildlife recommends before traveling from lake to lake:

  1. Clean: Inspect your boat, trailer and gear. Remove all plant material and mud.
  2. Drain: Remove all water from the boat, as well as the motor, bilge, live wells and bait buckets.
  3. Dry: Open all compartments and allow the boat and trailer to dry for at least a week or more before going into another body of water.

If the boat cannot be dried for a week, it is recommended that the boat be washed with high pressure and soapy water.

If your boat has been stored in water with zebra mussels, TPWD said it needs to be decontaminated before moving. Call (512) 389 - 4848 for guidance.

Here are the lakes, creeks and other bodies of water where zebra mussels have been found in Texas, according to the United States Geological Survey:

  • Austin-Travis Lakes (Colorado River at Lady Bird Lake, Lake Travis, Lake Austin)
  • Bois D’arc Island (Dean Gilbert Lake, Randell Lake, Shawnee Creek)
  • Bosque River (Waco Lake)
  • Cowhouse Creek (Belton Lake)
  • Denton Creek (Southern end of Grapevine Lake)
  • East Fork Trinity (Lavon Lake, West Prong Sister Grove Creek, Ray Hubbard Lake)
  • Elm Fork Trinity River (Fishing Hole Lake, Lewisville Lake, Ray Roberts Reservoir)
  • Lake Fork (Lake Fork Reservoir, Lake Fork Creek)
  • Lake Texoma
  • Lampasas River (Stillhouse Hollow Lake)
  • Leon River (Belton Lake)
  • Little River
  • Lower Colorado-Cummins (Walter E. Long Reservoir)
  • Lower Trinity-Kickapoo (Trinity River at Lake Livingston)
  • Lower West Fork Trinity River (Lake Worth)
  • Middle Colorado (Colorado River at O.H. Ivie Reservoir)
  • Middle Guadalupe (Guadalupe River at Lake Dunlap, Lake Placid)
  • Richland (Richland Creek at Richland Chambers Reservoir)
  • San Gabriel (Granger Reservoir, Lake Georgetown)
  • Upper Guadalupe (Canyon Lake, Turkey Cove)
  • Upper West Fork Trinity (Eagle Mountain Lake, Lake Bridgeport)