Travis County’s Walter E. Long Lake is infested with zebra mussels, according to the Texas Parks and Wildlife Department (TPWD).
Diversion Lake, a private-access lake in Medina County, was also recently classified as fully infested by these invasive mussels.
Brian Van Zee, TPWD Inland Fisheries regional director, said, “Unfortunately, zebra mussels have now spread to 34 Texas lakes, with 30 now fully infested, but there are far more lakes in Texas that still haven’t been invaded and are at risk,” Zee said.
Zebra mussels are mainly spread by boats. Park and lake visitors can prevent the larvae of zebra mussels from spreading to new waters, Zee said.
“Each boater taking steps 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,” he explained.
Transporting zebra mussels and other invasive aquatic animals in Texas can lead to a $500 fine.
Lake Walter E. Long received a “positive” designation in October 2018 and May 2019 following the repeated detection of zebra mussel larvae, per the TPWD. But searches for “settled mussels” in 2021 did not detect any juveniles or adults.
In early August of this year, City of Austin watershed protection biologists conducted shoreline searches for zebra mussels at Walter E. Long and found two adults, indicating an “established population.”
Zebra mussels can cause damage to aquatic environments in Texas lakes, as well as damage to water infrastructure, according to Texas Parks and Wildlife. They are also said to impact recreational lake activities negatively.
Zebra mussels were first detected in the Lone Star State in 2009, according to the Texas Parks and Wildlife website, when they were found in Lake Texoma.
Another invasive mussel species, the quagga mussel, has also been seen in Texas. It was found in Lake Amistad in 2021.
Over 50 types of mussels are found in the state, The Dallas Express previously reported, but not all of them are harmful like the zebra mussel. Many native species play an important role in Texas lakes, and the U.S. Fish & Wildlife Service has called them the “livers of the rivers.”
Common mussels, such as the Texas fawnsfoot, Texas hornshell, and Texas pimpleback, can filter up to 15 gallons of water in a single day. However, a blog post from the U.S. Fish & Wildlife Service shared that many of these aquatic species are declining.
“Unfortunately, many of these native mussel species are declining due to habitat loss, declines in water quality, changes in stream flow rates, and major impoundments (dams),” the post shared. High water temperatures, droughts, and floods are expected to worsen these threats.
Texas Parks and Wildlife and its partner agencies continually monitor Texas lakes for invasive species.