TPWD designates Lake Buchanan as 'infested' with zebra mussels

The Texas Parks and Wildlife Department says it has designated Lake Buchanan as "infested" with invasive zebra mussels, meaning that there is an established, reproducing population of zebra mussels in the lake.

The designation is a result of recent sampling efforts that revealed new evidence of a reproducing population of zebra mussels in the lake.

According to TPWD, Lower Colorado River Authority scientists discovered zebra mussel larvae in plankton samples taken from three sites around the lake in October. TPWD then confirmed the identity through microscopic and genetic analysis. The LCRA analyzed samples collected in November and again found zebra mussels at two of the three sites. Then in early December, crews working on a floodgate project at Buchanan Dam discovered several settled zebra mussels.

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Additional surveys for settled mussels were conducted by LCRA on the shorelines while Lake Buchanan Conservation Corporation volunteers also checked their installed settlement samplers. Zebra mussels were not detected at any of these locations. Although few settled mussels were found at the dam, TPWD says the presence of both larvae and adults and detection of young larvae in samples taken a month apart indicate that a reproducing population is present in the lake.

"At this time, the results indicate that the population in the lake appears to be small," says Monica McGarrity, TPWD Senior Scientist for Aquatic Invasive Species Management. "However, as we have seen in other Texas lakes, the population is likely to increase rapidly over the next few years."

To date, zebra mussels have not been found in nearby Inks Lake, but due to its location immediately downstream from Lake Buchanan, TPWD says it is likely to become infested in the near future. Shoreline surveys at Inks Lake conducted by LCRA and TPWD, as well as checks of settlement samplers by Boy Scout citizen science partners did not locate any settled mussels.

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Fall plankton samples were also free of zebra mussel larvae, says TPWD. However, zebra mussel environmental DNA was detected in fall samples from one site on the lake, which could be an early indicator of zebra mussel introduction.

TPWD is encouraging boaters and homeowners on both Lake Buchanan and Inks Lake to keep an eye out for settled zebra mussels and report any suspected organisms with photos. Zebra mussels grow to approximately 1-1.5 inches in length and have triangular, typically striped brown/tan shells. Unlike native mussels or non-native Asian clams, zebra mussels adhere strongly to hard surfaces.

RELATED: 17 Texas lakes now confirmed with invasive zebra mussels

"Although zebra mussels are now found in 31 Texas lakes, there are still many other lakes in the state that they haven’t invaded. Boaters play a critical role in preventing them from spreading to new lakes. Before traveling from lake to lake, clean, drain and dry your boat and gear. Remove plants, mud and debris, drain all the water from the boat and gear, and then open up compartments once you get home and allow everything to dry completely," advises Brian Van Zee, TPWD Inland Fisheries Regional Director.

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Boaters are advised that if they have stored their boat in the water at a lake with zebra mussels, it is likely infested with zebra mussels and poses an extremely high risk for moving this invasive species to a new lake. Before moving the boat to another lake, boaters are asked to call TPWD at 512-389-4848 for guidance on decontamination.

The transport of aquatic invasive species can result in legal trouble for boaters or transporters. TPWD says that transporting prohibited invasive species in Texas is illegal and punishable with a fine of up to $500 per violation. Boaters are also required to drain all water from their boat and onboard receptacles, including bait buckets, before leaving or approaching a body of freshwater.



A status map showing all lakes where zebra mussels have been found in Texas is online. Other Austin-area lakes identified by the map as infested include Lake Pflugerville, Lake Austin, and Lake Travis. Walter E. Long Lake has also tested positive. 

TPWD and partners monitor for zebra mussels in Texas lakes, but anyone who finds them in lakes where they haven’t been found before should report them by emailing photos and location information to to help identify new introductions. Anyone who spots them on boats, trailers, or equipment that is being moved should immediately report the sighting to TPWD at 512-389-4848.

To learn more about zebra mussels and other invasive species in Texas, click here. Information for marinas and owners of boats stored in the water on lakes with zebra mussels can be found on the TPWD website.