AUSTIN (KXAN) — Lake Waco, a popular spot for boaters and fishermen, recently earned a unique distinction — it’s the only Texas reservoir that has eradicated its Zebra mussel population.
The lake earned the title back in 2021 after a five-year study of the waters following an infestation that began the same year.
As part of Earth Week, we’re taking a closer look at this project and what we can learn from it.
Why Zebra mussels are bad for the environment
“We really have the perfect habitat for them to take advantage of and to spread out of control,” said Chase Smith Ph.D., a freshwater mussel researcher with the University of Texas. Smith says that Zebra mussels were first introduced to North America in the 1980s, likely brought over by a boat traveling from Russia.
In the last 20 years, the mussels have found their way to Texas and have had a major impact on our waterways.
“They will actually take all the nutrients out of the habitats that they’re in,” Smith said. This can be bad for wildlife in those waterways, especially other freshwater mussels.
“They will actually latch on the freshwater mussels and choke them out and kill them,” Smith said. In a healthy environment, Smith said that freshwater mussels filter every drop of water that flows down a river.
Zebra mussels can attach themselves to some challenging surfaces, including pipes and boats. They can damage utility company water lines and other equipment.
Zebra mussels, however, also filter water.
“When you consider that one Zebra mussel can filter out a gallon of water or more every single day, and you have a population of hundreds of thousands, or maybe millions of mussels, doing that every day, day in and day out. Over time, those reservoirs tend to get clear,” said Michael Baird with Texas Parks and Wildlife.
The Lake Waco Zebra Mussel project
Baird was part of the team that eradicated the mussels in Lake Waco. In 2014, Texas Parks and Wildlife trained staff in Waco to identify Zebra mussels. In September of that year, the training paid off. Around 80 mussels were found at a Lake Waco dock. They were brought into the water by a boat that recently visited Lake Belton, which is infested with the creatures.
With little time before the mussels spread to the rest of the lake, Tom Connery, a city employee, came up with a plan.
“Smother any remaining Zebra mussels in the area by laying out large sheets of plastic and weighing them down with sandbags,” Baird said.
Then, they waited. When they check the water for new juvenile Zebra mussels, they were unable to find any. “For the next five years, nothing, we didn’t find anything. In 2021, the lake was was said to be Zebra mussel free.”
Smith said the plastic method likely did one of two things — smothered them and deprived them of oxygen, or caused them to overheat. Zebra mussels only thrive in certain water temperatures and can not survive extreme heat.
Zebra mussels across Texas
Baird said that 30-40 reservoirs in Texas are currently infested with Zebra mussels. Lake Waco is the only one that has eradicated them. He said it was possible because the mussels were caught so early.
“If you’re finding out five or six months later, by that point, it’s probably too late,” Baird said.
“I don’t think being able to take them out at this stage is a possibility within the United States, but I think, you know, over time, there’s certainly a way that we can control them,” Smith said.
He used the Asian clam as an example, an invasive species that is now found in many lakes and has become part of the ecosystem.
Smith said that using chemicals or introducing a predator to eliminate the Zebra mussels could be dangerous for the overall ecosystem. Baird agrees, saying that the only way to protect native wildlife is to prevent their spread.
So how do we prevent their spread?
- Boaters need to clean, drain and dry their boats after they leave the lake and before entering a lake. Zebra mussels spread by attaching to boats.
- Learn to identify Zebra mussels so authorities can take action before they get out of control.
- If Zebra mussels are found and in small enough numbers, getting creative like with Lake Waco’s plastic sheet method could work.