State water managers issued a warning Monday for people and pets to stay out of Lake Perris in Riverside County due a hazardous algal bloom.

Lake Perris, or Perris Reservoir, is a popular fishing, boating, and camping site between Moreno Valley and the City of Perris.

California’s Department of Water Resources issued an advisory after tests showed elevated levels of blue-green algae or cyanobacteria.

DWR says algal blooms are typically caused by warm water temperatures, calm conditions, and certain nutrients in the water. They can produce toxins harmful to people and pets.

The signs of Harmful Algal Blooms, according to DWR

• Small blue-green, green, white, or brown particles in the water
• Streaks in the water that look like spilled paint
• Mats, scum, or foam at the surface or along the shoreline
• Can have an odor described as gasoline, septic, or fishy

What are the Dangers?

• Some algal blooms can produce toxins that are harmful to people and pets
• Dogs and small children are most likely to be affected by HABs due to their smaller body size and the probability of playing in the water for longer periods
• Animals can be especially susceptible to the toxins because they tend to drink while in the water and lick their fur afterward
• Exposure to toxic cyanobacteria can cause eye, nose, mouth, or throat irritation, headache, allergic skin rash, mouth ulcers, vomiting, diarrhea, and cold- and flu-like symptoms