The Texas Parks and Wildlife Department (TPWD) has officially designated Lake Meredith, near Amarillo, as fully infested with invasive zebra mussels — a milestone that confirms an established, reproducing population now exists throughout the reservoir. The announcement marks a significant westward expansion of one of Texas’ most damaging aquatic invasive species.

Early Signs Lead to Rapid Confirmation

In late May, partners with the U.S. Geological Survey’s Zebra Mussel Monitoring Program detected potential microscopic larvae in routine samples taken from three locations on the lake. TPWD’s Analytical Services lab quickly verified the specimens through genetic testing, confirming the presence of zebra mussels.

Around the same time, the Canadian River Municipal Water Authority (CRMWA) reported multiple settled mussels found on a camp chair retrieved by anglers. The mussels represented several size classes — evidence that reproduction likely occurred last fall and again this spring.

TPWD’s Amarillo Fisheries District staff immediately surveyed shoreline rocks across multiple sites. Their findings were consistent: settled mussels of varying sizes at every location checked. The results point to a well‑established population now dispersed throughout Lake Meredith.

A Concerning Step in the Westward Spread

“Unfortunately, detection of zebra mussels at Lake Meredith is a continuation of a trend in recent years of westward spread of this highly invasive species,” said Monica McGarrity, TPWD senior scientist for aquatic invasive species. “This new infestation in a new river basin in the Panhandle provides a particularly concerning steppingstone for further spread to uninvaded western states.”

McGarrity emphasized the importance of boaters properly cleaning, draining, and drying their vessels — or seeking professional decontamination if stored in infested lakes — to prevent further spread and avoid fines or delays when traveling between states.

Impacts on Lakes, Infrastructure, and Recreation

Zebra mussels attach to hard surfaces, disrupt lake ecosystems, harm native species, and damage water supply infrastructure. Their sharp shells accumulate along shorelines, creating hazards for swimmers and lakefront visitors.

CRMWA General Manager Drew Satterwhite noted that the authority has long invested in prevention — from boat cleaning stations and signage to detection dogs during major fishing tournaments. “Now that zebra mussels are established in Lake Meredith, we will be focusing our efforts toward more comprehensive mitigation strategies to limit the impacts to our water infrastructure,” he said.

Boaters Play a Critical Role

Zebra mussels often spread when boats move between lakes. They cling to hulls, anchors, ropes, and any gear left in the water. Their larvae — invisible to the naked eye — can survive in residual water inside boats for days.

“Invasive mussels have now spread to 40 Texas lakes, with 35 fully infested,” 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 can make a big difference.”

Lake Meredith already has boat cleaning stations at several access points to help visitors comply with prevention guidelines.

Clean, Drain, Dry — The Three Essential Steps

TPWD urges boaters to follow these steps every time they leave a lake:

• Clean: Remove plants, mud, and debris.
• Drain: Empty all water from boats, motors, live wells, and gear.
• Dry: Open compartments and allow everything to dry completely for at least a week, when possible.

National Park Service Reinforces the Call

“The National Park Service remains committed to collaborating with our state and local partners to monitor and minimize the spread of zebra mussels,” said Joe Graff, acting superintendent of Lake Meredith National Recreation Area. He encouraged visitors to use designated cleaning stations and follow all “clean, drain, dry” requirements.

Legal Requirements and Reporting

Transporting prohibited aquatic invasive species in Texas is illegal and can result in fines up to $500 per violation. State law also requires boaters to drain all water from their vessels and remove invasive plants before leaving or approaching any freshwater body.

Boaters moving equipment stored in infested lakes — such as docks, pumps, lifts, or barges — should call TPWD at (512) 389‑4848 for decontamination guidance.

Anyone who spots zebra mussels on boats or equipment being moved can help prevent new introductions by reporting sightings to TPWD. New lake detections can be reported by emailing photos and location details to aquaticinvasives@tpwd.texas.gov.

More information, including a short instructional video, is available on the TPWD YouTube channel, and additional resources can be found at tpwd.texas.gov/StopInvasives.