LAKE LBJ, Texas (KXAN) — A photo taken at Lake LBJ that’s circulating appears to show a giant cluster of Zebra mussels attached to a floatation mat — it’s real!

Sarah Entzminger took the photo of her family’s float. She says they flipped it over to find the creatures barnacled underneath. Entzminger says she didn’t notice them on the float last summer.

What’s a Zebra mussel?

These invasive, rapidly-producing, finger-sized mollusks arrived in North America from Eurasia in the 1980s, experts say. After invading the Great Lakes region, they began appearing all across the U.S. The species was discovered in Texas in Lake Texoma in 2009, and has been spreading ever since. Back in 2019, Zebra mussels were the culprit behind a foul odor in Austin city water after they were discovered in a pipeline at the Ulrich Water Treatment Plant.

John Higley, CEO of EQO, an Austin-based biotech company that helps manage invasive species, says that because Zebra mussels feed on “good” algae in bodies of water, it gives toxic algae — which can be deadly to dogs — free reign. This algae, also known as cyanobacteria, is blue-green in color and is known to have caused the deaths of at least five dogs after swimming in bodies of water in Austin in 2019.

Lake LBJ is one of six local lakes infested with zebra mussels. Texas Parks and Wildlife say there must be an established reproducing population in a lake for it to be considered fully infested.

The other lakes include Lake Travis, Lake Georgetown, Lady Bird Lake, Marble Falls and Pflugerville. Walter E. Long is considered a positive lake — meaning Zebra mussels or larvae were detected on more than one occasion.

Recently, Texas Tech University researchers found that dogs may be an integral part of the battle against the species: using their nose to sniff out the mollusks in bodies of water, in addition to soil samples.