Dogs are dying from swimming in lakes with toxic algae. Are SLO County pets at risk?

Toxic blue-green algae has popped up in lakes around the country this summer, with deadly results for dogs.

But do San Luis Obispo County pet owners have anything to worry about?

There have been no recorded instances of the toxic algae in the county so far this summer, but local lakes have made the state’s list in recent years. Last summer, a warning was posted at Laguna Lake in San Luis Obispo.

Even without any local toxic algae blooms, San Luis Obispo’s natural resources manager Bob Hill recommends pet owners should avoid letting their dogs swim in lake water as a general rule and act with “an abundance of caution.”

What is blue-green algae?

Blue-green algae, also known as cyanobacteria, release cyanotoxins that can seriously harm the nervous system, with potentially deadly effects for animals. The algae is more likely to grow during hotter summer months.

Inhalation or contact with the toxic algae can result in irritation of the skin, eyes, nose and throat as well as breathing irritations, according to the Centers for Disease Control and Prevention. The toxins have been known to kill pets and other animals, but not humans.

The bacteria from the algae has been blamed for the deaths of three dogs who swam in a North Carolina pond earlier this month. All three dogs experienced seizures and were dead within hours. The owner’s Facebook post announcing their deaths and warning of toxic algae has been shared more than 32,000 times as of Aug. 20.

How do I know if a lake has blue-green algae?

The county’s water quality lab manager Faith Zenker said blue-green algae is usually visible, and it is helpful to familiarize yourself with the appearance of normal versus toxic algae.

“Normally, you would see a sheen to the water or see the algae,” Zenker said. “Blue-green a lot of times is very buoyant and you’ll see it on the surface.“

Atas Algae035
Atascadero Lake has a plant-like spongy floating algae. Photo taken Saturday, August 17, 2019. Laura Dickinson ldickinson@thetribunenews.com

So far this summer, no lake in San Luis Obispo County has been found to have toxic algae blooms, but several have been noted on the state’s list in recent years.

A map tracking harmful algae blooms around California includes information voluntarily reported by local agencies. You can visit mywaterquality.ca.gov to see when blooms were last reported and how severe they were.

The most recent recording of harmful algae on the Central Coast was at Lake San Antonio in June. But since 2016, toxic algae has been reported at other local lakes, including Nacimiento, Lopez and Atascadero.

How often are lakes tested?

Water quality in lakes and reservoirs are tested weekly to monthly.

Laguna Lake, for example, is tested weekly.

When low levels of blue-green algae were detected at the lake last August, caution signs were put up and remain today as a warning, despite no detected levels of blue-green algae recently.

In the North County, Lake Nacimiento and Santa Margarita Lake are tested once every month. Whale Rock Reservoir near Cayucos is tested twice per month.

In the South County, Lopez Lake is tested once a month and weekly during summer.

Atascadero Lake is tested at least twice monthly during non-winter months.

Atascadero public works director Nick Debar, who tracks conditions at Atascadero Lake, wrote that even when there is no visible or detected toxic algae, pet owners should precede with caution.

“Dogs will instinctively want to taste (and) drink water if they are in a lake swimming or wading,” Debar wrote. “As tempting as it is to allow your dog to cool off in the lake, pet owners should keep their dogs out of the lake.”

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