Established, Reproducing Population of Zebra Mussels Found in Lake Austin

The Texas Parks and Wildlife Department announced this February 2018 that Lake Austin has an established, reproducing population of zebra mussels and that the lake’s status has been upgraded to a classification of “infested.” The new classification follows TPWD and Lower Colorado River Authority testing, which found several sizes of adult zebra mussels and larvae in numerous Lake Austin locations, including at Tom Miller Dam and Pennybacker Bridge.

Lady Bird Lake has been upgraded to a classification of “suspect,” after LCRA found larvae in a plankton sample. In June 2017, zebra mussels were identified upstream along the Colorado River in Lake Travis.

The upgraded Lake Austin result was not surprising, said TPWD Aquatic Invasive Species Team Lead Monica McGarrity. “When zebra mussels were found in the Colorado River Basin we knew it was likely that larvae would disperse and invade downstream water bodies. But downstream dispersal doesn’t spread zebra mussels to new river basins — boats do — and boats can spread them downstream more quickly.”

Zebra mussels are rapid reproducers and “can harm native freshwater mussels and other aquatic species, affect water clarity and cause harmful algal blooms, cover shoreline rocks and litter beaches with sharp shells, clog water intakes, damage or increase maintenance on hydroelectric and other facilities using raw surface water, and damage boats and motors left in infested waters,” according to a TPWD news release.

There are now 14 bodies of water in five Texas river basins that are considered infested. Five bodies of water have been “positive” more than once, and three bodies of water are suspect.

McGarrity said Texans can protect other river basins from the rapid spread of zebra mussels by being diligent about cleaning, draining, and drying boats and gear every time they visit a lake or river.

Inland Fisheries Regional Director Brian Van Zee cautioned that even though zebra mussels may not be visible, “microscopic hitchhikers could still be hiding in your equipment.”

It is illegal in Texas to possess or transport dead or alive zebra mussels. Learn more at tpwd.texas.gov/ZebraMussels.