A no water contact advisory for Upper Castaic Lake was issued Thursday by the Los Angeles County Department of Parks and Recreation due to harmful algae in the water.
The algae is believed to contain toxins that may pose health risks to both humans and animals, according to a statement from the department.
Exposure to the algae may cause skin rashes, eye irritation, diarrhea, and vomiting in humans while animals exposed may experience diarrhea, vomiting, seizures, and, in severe cases, death, the statement said.
As a precaution, all recreational boating activities, including windsurfing and the use of personal watercraft, are prohibited, the department announced.
Department officials urged the public not to eat fish or shellfish or drink any water from the affected water, emphasizing that boiling and filtering the water will not render it safe for consumption.
Anyone experiencing symptoms after contact with the water should seek immediate medical attention, while pet owners should contact a veterinarian if their animals show signs of illness.
More information on harmful algae is available on the state Water Quality Monitoring Council web page, mywaterquality.ca.gov/habs/resources/faq.html.