Officials trying to safeguard Lake Waco against the zebra mussel menace have scored a tentative victory.
Texas Parks and Wildlife Department officials received word late last week that there were no traces of zebra mussel larvae or DNA in samples taken from the lake Dec. 4.
A colony of zebra mussels was discoveredaround the Ridgewood Country Club dock in September. The city of Waco reacted by installing a football field-size tarp to smother them before lake temperatures dropped to the ideal breeding range. The tarp will be removed in about a month.
John Tibbs, a Waco-based Texas Parks and Wildlife biologist, said it is too early to declare the mussels vanquished, but no news is good news.
“It’s not a slam-dunk,” he said. “The real test is when we sample in the spring. It’s promising, and we’re cautiously optimistic.”
The invasive Eurasian mollusk has wreaked havoc on ecosystems in many Upper Midwest lakes and clogged intake pipes for municipal water supplies.
The species has spread to seven Texas lakes, including Lake Belton, hitching a ride on boats. City officials think a mussel-infested work barge that was docked at the country club last summer brought the mussels to Lake Waco from Lake Belton.
Tibbs said if the tarp strategy proves to be successful, it could be useful for containing other zebra mussel populations, but only in limited circumstances. He said it is rare to find a small population like the one at Lake Waco. More commonly, zebra mussels spread throughout a lake before they are detected, he said.
Tibbs said biologists last fall found traces of zebra mussel DNA in water samples at Lake Whitney and Lake Granbury. So far, no actual zebra mussels or larvae have been found in those lakes, but if they get established in those lakes, officials are concerned the species could colonize the entire Brazos River basin downstream, he said.
State law requires any boater launching into public waters to first clean, drain and dry the craft to avoid the transfer of mussels or their microscopic larvae.
Tibbs said state parks officials will step up their enforcement and inspection efforts this summer.
For the past couple of summers, the state parks department has cooperated with the city of Waco to do spot inspections of boats entering Lake Waco.
City spokesman Larry Holze said he expects the city will put in at least as much effort this year to safeguard the lake against a zebra mussel invasion.