AUSTIN (KXAN) — The Austin Watershed Protection Department is currently testing algae found at Auditorium Shores, located at Town Lake, for possible toxins — which are still being found in the algae at Festival Beach and Red Bud Isle.

Watershed protection says dogs should not swim in or drink from any part of Lady Bird Lake.

(Courtesy of Austin Watershed Protection)

Toxic algae in Austin

Recently, the department started monitoring Lady Bird Lake on a weekly basis as temperatures began rising — which expert Brent Bellinger says causes the algae to thrive in stagnant areas.

“We’re still putting all those puzzle pieces together. It’s a complicated story,” Bellinger told KXAN last month. “In general, cyanobacteria seem to do really well when water temperatures exceed 25, 27, 30 degrees centigrade [about 77-86 degrees Fahrenheit].”

In 2019, toxic algae — called cyanobacteria — produced toxins and created algae blooms, which resulted in at least five dogs dying after swimming in the water.

Around the summer of last year, City of Austin scientists said that nearly 40 percent of the water around Red Bud Isle was covered in blue-green algae.

Cyanobacteria is blue-green in color and is dangerous for humans and animals.

When dogs ingest contaminated water, city officials say, it can cause them to experience a range of symptoms, including excessive drooling, foaming at the mouth, vomiting, diarrhea, stumbling, muscle twitches and respiratory paralysis.

In August, KXAN spoke to Claire Saccardi, one of the owners who reported her dog’s death. She said her four-year-old Golden Retriever Harper started showing symptoms within an hour and a half of being in the water.

“All of the sudden, she started walking down a step and she collapsed,” Saccardi said. “Both of her front legs stopped working. She couldn’t stand up. She looked at me with the saddest little puppy eyes.”

The emergency veterinarian who treated Harper listed blue-green algae intoxication as a suspected cause of death.

Why the rise in blue-green algae?

According to John Higley, CEO of EQO, an Austin-based biotech company that helps manage invasive species, there’s one likely culprit contributing to the rise of blue-green algae.

It’s Austin’s other aquatic nuisance: zebra mussels.

These invasive, rapidly-producing, finger-sized mollusks arrived in North America in the 1980s, experts say. After invading the Great Lakes region, they began appearing all across the U.S.

Zebra mussels are razor sharp — easily cutting through clothing — and Travis County Parks officials said last summer that several swimmers reported injuries because of them. They attach to boats and most hard surfaces in water bodies, officials say.

Because they feed off “good” algae, experts say, and release blue-green algae back into the water.

Earlier this year, a West Texas reservoir became the 30th Texas lake to fall prey to the species.

Anyone who believes they have seen zebra mussels in Texas waterways is encouraged to email photos and location information to and report the sighting by calling (512) 389-4848.