Toxins detected in algae on Lady Bird Lake

The Watershed Protection Department has received the test results from algae that had been sampled on July 14, 2020. University of Texas researchers have confirmed the presence of dihydroanatoxin within the algae samples from Festival Beach and Red Bud Isle.

Dihydroanatoxin is one of several possible toxins that cyanobacteria, also called blue-green algae, can produce. It is the same toxin that was produced last year. 

The toxin is contained within the algae and has not been released into the water, according to the Watershed Protection Department. This means that currently, exposure to the toxin would occur through touching or ingesting the algae, not through contact with the water. 

Additional signage is being placed along Lady Bird Lake to help alert the public to the presence of toxins. Dog owners should not allow their pets to swim in or drink from Lady Bird Lake. People should also avoid handling the algae. 

"We will continue weekly monitoring of algae at four locations on Lady Bird Lake, including Red Bud Isle, the mouth of Barton Creek, Vic Mathias Shores and Festival Beach," the Watershed Protection Department said in a press release. "Information about water temperature, flow, the presence of algae, and testing results are available on a dashboard at"



Dogs were particularly vulnerable to the harmful algae bloom that occurred last year. At least five dogs died after swimming in Lady Bird Lake during the summer of 2019. Dog owners should take their pets to a veterinarian immediately if their dogs become sick after swimming in Lady Bird Lake.

Dog owners are also asked to report the illness to 3-1-1.

Symptoms of exposure may include: 

  • Excessive drooling, vomiting, and diarrhea 
  • Foaming at the mouth 
  • Jaundice and hepatomegaly 
  • Blood in urine or dark urine 
  • Stumbling 
  • Loss of appetite 
  • Photosensitization in recovering animals 
  •  Abdominal tenderness 
  • Progression of muscle twitches 
  • Respiratory paralysis 

Click here to look at the algae dashboard provided by the City of Austin.