The City of Austin says it has found potentially dangerous blue-green algae blooms at Auditorium Shores and Barton Creek downstream from Barton Springs Pool. The algae samples contain neurotoxins that are similar to those found earlier this month at Red Bud Isle, but the city says the concentration of neurotoxins is higher.

The city first discovered the algae roughly two weeks ago after multiple pet-owners reported their dogs dying shortly after swimming in Lady Bird Lake. Officials closed Red Bud Isle last week.

In a statement this evening, the city said dogs shouldn't swim in the lake and residents should avoid contact with the water.

The city said water at the Barton Creek spillway, known as Barking Springs, didn't test positive for the algae, but urged caution in the event that the algae spread.

"At this time, we believe people and pets can continue to swim in this area at their own risk," the city said. "They should avoid going downstream to areas with floating algae. They should be aware that bacteria is always a concern in smaller waterways where there is a high concentration of dogs."

The Austin Watershed Department tested eight sites last week for the algae, but said it would test more sites on Lady Bird Lake tomorrow. Red Bud Isle is expected to be closed for the next several weeks, as the city hasn't yet found an "effective way to treat or remove" the potentially dangerous algae.

The city says the blue-green algae could be potentially harmful to humans. Officials say the algae could cause respiratory failure in dogs, and urges owners to monitor pets if they have ingested the water. Owners should take pets to the vet if they exhibit the following symptoms:

• Excessive drooling, vomiting, diarrhea

• Foaming at the mouth

• Jaundice, hepatomegaly

• Blood in urine or dark urine

• Stumbling

• Loss of appetite

• Photosensitization in recovering animals

• Abdominal tenderness

• Progression of muscle twitches

• Respiratory paralysis

Austin Public Health says it hasn't seen any emergency room admissions related to these symptoms in humans.