Texas Parks and Wildlife Department recently declared Lake Nasworthy as the latest body of water to be “infested” with invasive zebra mussels.
This designation means there is an established reproducing population at Nasworthy.
Officals confirmed zebra mussel larvae (veligers) were present in mid-March based on plankton samples collected in November 2024, during the fall spawning period. Zebra mussel larvae were detected in samples collected at two sites on the lake, near the Knickerbocker Road bridge and the dam.
“Unfortunately, the zebra mussel infestation of Lake Nasworthy is part of a trend in recent years of spread of this highly invasive species to lakes in the western part of the state,” said Monica McGarrity, TPWD senior scientist for aquatic invasive species. “All boaters taking steps to properly clean, drain, and dry boats to prevent the spread of invasive species is critical to stopping the further spread of zebra mussels.”
Larve were not detected from samples taken at Twin Buttes Reservoir.
Zebra mussels are problematic as they damage boats and water supply infrastructure, alter lake ecosystems and cause harm to native species.
They also make shorelines more dangerous with the remains of sharp shells.
Zebra mussels are most often transported on or in boats, so boaters play a critical role in preventing them from spreading to new lakes.
“Invasive mussels have now spread to 38 Texas lakes, with 34 fully infested, but there are far more lakes that still haven’t been invaded and are at risk,” said Brian Van Zee, TPWD Inland Fisheries Regional Director. “Each boater taking the necessary actions to clean and drain their boat before leaving the lake and allowing compartments and gear to dry completely when they get home can make a big difference in protecting our Texas lakes.”
TPWD urges boaters to follow these three simple but crucial steps to clean, drain and dry boats and gear before traveling from lake to lake. Remove plants, mud and debris; drain all water from the boat and gear; once back home, open compartments and allow everything to dry completely for at least a week, if possible.
If a boat or other equipment, such as barges, docks, lifts, pumps, etc., have been stored in the water at a lake with invasive mussels, they are likely infested and pose an extremely high risk for transporting these invasive species to a new lake unless they are properly decontaminated. Before moving a boat or other equipment that has been stored in the water, call TPWD at (512) 389-4848 for guidance.
In addition to the harm that invasive species can cause to aquatic ecosystems, water infrastructure and the recreational experience at lakes, the transport of these organisms can result in legal trouble for boaters. Transporting prohibited aquatic invasive species in Texas is illegal and punishable with a fine of up to $500 per violation.
It’s also the law that boaters must drain all water from their boat and onboard receptacles, including bait buckets, before leaving or approaching a body of fresh water. They must also remove all invasive plants from the boat and trailer before leaving a lake.
