Zebra mussels, giant salvinia, and now quagga mussels continue to have devastating economic, recreational, and environmental impacts in Texas. What's worse is that boaters are unknowingly helping to spread these invasive species throughout the state.
The clean, drain, and dry method continues to be the best way to prevent their spread.
According to Texas Parks and Wildlife Department (TPWD), the first Texas zebra mussel infestation was found in Lake Texoma in 2009, and quagga mussels were first detected in Lake Amistad in 2021. Another lake was added to the infected list in May: Hords Creek Lake in Coleman County, south of Abilene.
Zebra mussels are often spread from lake to lake on or in boats. TPWD says the mussels attach to boats or anything left in the water, like anchors, and can survive for days out of the water. The larvae are not visible to the naked eye, so oftentimes, boaters don't know they're transporting them.
Zebra mussels are currently found in lakes and rivers in six river basins across the state—the Red, Trinity, Brazos, Colorado, Guadalupe, and San Antonio rivers. Quagga mussels are currently found in a single lake in the Rio Grande basin.
Currently, Lake Waco is the only reservoir to have successfully eradicated zebra mussels. Zebra mussels were first detected in the lake in 2014, but by 2021, the lake was declared free of the species.
Giant salvinia, a highly invasive, free-floating aquatic fern that can double in size in less than a week under ideal growing conditions, is one of the major threats to aquatic ecosystems in Texas. The invasive plant produces thick mats making fishing, boating, swimming, and other water recreation nearly impossible.
Giant salvinia is not currently preventing fishing or boating access in Texas public waters; there is still a chance of plants hitchhiking from one lake to another on a boat, trailer, or other equipment.
"There's no doubt that Texans love their lakes, but we also need Texans to take action to help protect them," TPWD aquatic habitat enhancement team lead John Findeisen said in the release. "It only takes a tiny fragment of an invasive plant to create a new infestation and preventing aquatic invasive species introductions avoids costly, long-term efforts to manage these species once they infest a lake. An ounce of prevention is worth a pound of cure—it only takes a small amount of our time as responsible boaters to clean, drain, and dry our boats and equipment to prevent new introductions of aquatic invasive species."
Go here to see a map of infested, positive, and suspect waters in Texas with zebra and quagga mussels.
TPWD encourages boaters to clean, drain, and dry boats and gear before moving between lakes. This includes removing all plants, mud, and debris. Everything should be allowed to dry completely for at least a week, if possible.
Take Care of Texas offers a great explanation of the clean, drain, dry method to avoid aquatic hitchhikers:
- Clean: Remove all plants, animals, and mud, and thoroughly wash the boat and trailer. A trip to the car wash to use high-pressure spray nozzles can help clean crevices and hidden areas. Keep in mind that a boat stored in infested waters may need to be professionally decontaminated.
- Drain: Pull the plug! Drain all water before leaving the area, including live wells, bilges, ballast, and engine cooling water.
- Dry: Allow your boat to dry completely before launching in other waters—ideally for a week or more.
Watch this video that shows how to properly Clean, Drain, and Dry your boat to prevent the spreading of invasive species.
In addition to the harm these organisms can cause to aquatic ecosystems and the recreational experience at lakes, the transport of aquatic invasive species can also result in legal trouble for boaters. Transporting prohibited invasive species in Texas is illegal and punishable with a fine of up to $500 per violation.
Be sure you understand how to clean, drain and dry your vessel before leaving or entering a lake or river.