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Monitoring of potentially toxic blue-green algae begins July 1 at 16 additional sites in the five upper Highland Lakes, the Lower Colorado River Authority recently announced. 

This comes after the LCRA noted a significant decrease in the toxicity level of blue-green algae collected June 10 at a Lake Travis monitoring site near where a dog that died in February was playing in the water. 

According to LCRA, the samples from the Travis Landing area “showed trace amounts of cyanotoxins were present, but not at quantifiable levels.” 

However, officials noted that algae species capable of producing toxins were still present. They urged people to avoid contact with the algae while in the lakes and keep their dogs from ingesting or playing in it.

According to the Centers for Disease Control and Prevention, people who come into contact with cyanotoxins could experience the following:

  • irritation of the skin, eyes, nose, throat, or lungs
  • and, if swallowed, stomach pain, headache, muscle weakness, dizziness, vomiting, diarrhea, or liver damage

Symptoms in dogs could show up as:

  • excessive salivation
  • vomiting
  • fatigue
  • staggered walking
  • difficulty breathing
  • convulsions
  • liver failure

In some instances, death of animals can occur within hours or days.

Blue-green algae are naturally occurring in all of the Highland Lakes and become more prevalent in the summer and early fall when the water temperature is warm. However, the algae can appear throughout the year.

“It’s good to see those toxicity levels fall, but this is no time to let your guard down,” said John Hofmann, LCRA executive vice president of Water. “Conditions can change rapidly, and blue-green algae can be harmless one day and harmful the next.”

It’s impossible for people to tell which algae are producing toxins by appearance alone.

In February, following the death of a dog, the LCRA began testing water and algae from the Travis Landing area and checking additional locations on Lake Travis and the other Highland Lakes.

In March, they confirmed the presence of measurable cyanotoxins near the Cottonwood Shores boat ramp on Lake Marble Falls and along the shoreline near the Inks Lake State Park boat ramp. In addition, officials detected toxicity in algae from 10 other sites on Lake Travis. 

The toxicity levels from the Travis Landing site remained at potentially dangerous levels until the June 10 collection.

Along with the LCRA monitoring the upper Highland Lakes, which also include LBJ and Buchanan, the city of Austin is testing samples from Lake Austin and Lady Bird Lake.

Blue-green algae can appear blue-green, dark green, brown, or black and intermix with other types of algae that don’t produce cyanotoxins. 

To minimize risk of exposure to cyanotoxins, the LCRA recommends:

  • avoiding areas with algae or areas that are stagnant;
  • if possible, keeping dogs leashed near shorelines;
  • not letting dogs consume lake water, algal material, or other shoreline debris;
  • not letting dogs lick their fur or paws after getting out of the water;
  • rinsing off dogs after contact with lake water;
  • and immediately taking a dog to a veterinarian if it becomes sick after swimming. 

For more information on blue-green algae in the Highland Lakes, check out the LCRA’s webpage