AUSTIN (KXAN) — Summer is near, and Austin’s blue-green algae season is already here.

The city said Tuesday that staff has found blue-green algae in Lady Bird Lake and Lake Austin. These algae are presumed to be toxic.

The Watershed Protection Department said blue-green algae was found at every monitoring site on Lady Bird Lake and Lake Austin except at the Walsh Boat Landing.

The city has documented toxic algae yearly since 2019 in Lady Bird Lake. Toxic algae have been found every year since 2020, when sampling began, in Lake Austin.

These algae toxins are contained in the algae itself, the city said, meaning exposure happens through ingesting or touching the algae.

The department’s initial tests were between May 2 and May 12, but initial lab results won’t be ready until June. After tests are completed at universities, the results are posted online.

“It’s hard to just tell with your eyes, what may or may not be toxic and what level of toxicity might be there,” said conservation program supervisor Brent Bellinger. “So we recommend doing your best to avoid interacting with the algae and keeping your dogs away from any of the floating mats as well.”

In the summer and early fall, city staff visit monitoring sites biweekly and test if algae are seen. Testing is paused during late winter and early spring, the city said.

The algae’s biomass is expected to peak in the summer. He said planktonic blooms generally favor droughts and warm weather for stagnant conditions and warm waters.

Bellinger said these types of algae are uncommon globally, but they are increasing and better studied now.

For two years, the Watershed Protection Department began adding lanthanum-modified clay to reduce the harmful algae on Lady Bird Lake. The clay reduces the phosphorus available to the algae to grow. The city said nutrient levels decreased near Red Bud Isle, but not on the east side of Interstate 35, which may be due to rainfall and increased flows.

Staff will start applying the clay in late June.

What should you do if you come into contact with toxic algae?

Because of the possibility of toxic algae, the city said people and pets should avoid contact with algae, not drink water from the lakes and rinse off after contact with water. Swimming is banned in Lady Bird Lake.

If someone has sudden, unexplained symptoms after swimming in the waters, they should contact a medical provider or the Texas Poison Control Center. Pet owners should contact a veterinarian.

Harmful Algae Bloom-Associated illness symptoms vary, according to the Centers for Disease Control and Prevention. Symptoms depend on how a person or animal was exposed, how long they were exposed, which type of toxin was present and how much toxin was present.

Toxic algae may be the cause of several dog deaths since 2019.