ST. GEORGE — With seasonal monitoring for known toxic algal blooms coming to an end, the Utah Department of Environmental Quality is advising the public to remain cautious when near tainted waterbodies, especially when out hunting with dogs.

At the end of September, 24 waterbodies across Utah were under either health watches or warning advisories for harmful algal blooms.

In southwest Utah, this includes Newcastle Reservoir, Panguitch Lake, Baker Reservoir, LaVerkin Creek, Left Fork of the Virgin River, North Fork of the Virgin River and lower Virgin River reaching from Zion National Park down into Arizona.

The last known status of these waterbodies can be found on the department’s website.

While harmful algal blooms are known to thrive during hot summer weather, they can persist during fall and winter seasons and remain a threat to humans and pets, particularly dogs.

On Oct. 31, the Utah Division of Water Quality will cease monitoring for harmful algal blooms as temperatures continue to decrease and weather conditions worsen, according to a press release from the state agency.

“Beginning at the end of October, some active advisories will be lifted, and signs and website posts will start to come down,” Dr. Hannah Bonner, Division of Water Quality environmental scientist, said. “However, it’s essential to know that these blooms can continue in colder weather. People should know what to look for, and when in doubt, keep your pets and hunting dogs out of the water.”

Blooms form when naturally occurring cyanobacteria, also known as blue-green algae, multiply to high densities and form visible water discoloration, scum and mats. Harmful algal blooms can look like pea soup, spilled paint, grass clippings or water that has a green or blue-green hue.

Cyanobacteria can produce several kinds of toxins that can affect liver, nerve and skin tissue. If you suspect a harmful algal bloom in the water, scientists warn to stay out of the water and avoid any contact with any water or scum. Be sure to clean waterfowl and fish with fresh water and discard all the remains.

A note for waterfowl hunters

This year, Utah’s duck hunting season runs from Oct. 7 to Jan. 20, 2024, for the northern part of the state and Oct. 14 to Jan. 27, 2024, for the southern portion. Utah Department of Environmental Quality officials are advising hunters who take their dogs with them during hunting season to be acquainted with signs of a harmful algal bloom and locations where preexisting blooms have been reported.

Hunters should also keep their pets away from rivers, ponds and reservoirs, if they suspect a harmful algal bloom, as the toxins have proven to be fatal in pets. Dogs can be exposed to toxins by skin contact with water that is contaminated with cyanobacteria or toxins, by drinking the water or by licking the algae off their fur.

If you suspect your pet has been exposed to a harmful algal bloom, officials advise to seek immediate care from a veterinarian. Even with proper veterinary care, most exposures are fatal. Prevention is the best way to protect your pet, the environmental scientists noted.

According to the Cornell University College of Veterinary Medicine, symptoms of exposure in dogs can include vomiting, diarrhea, weakness, pale gums, collapsing, drooling muscle tremors, difficulty breathing, muscle rigidity, paralysis, seizures and sudden death. The onset of systems can occur within 30-60 minutes of exposure.

Suspected harmful algal blooms can be reported to the Division of Water Quality by calling 801-536-4123.

People can learn more about harmful algal blooms and cyanobacteria at:

• Utah Division of Water Quality
• Zion National Park algal bloom page
• Environmental Protection Agency

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