A Fontana man was found alive and treated for injuries Monday morning after being reported missing at Castaic Lake by family Sunday afternoon.

57-year-old Luis Arellano was found by a member of the search party shortly before 9 a.m. Monday, after his family reported him missing during a picnic at the lake Sunday afternoon.

“Yesterday at approximately 3 (p.m.) lifeguards received a message from the family saying they’re missing their father,” said Tracy Hild, aquatics manager at Castaic Lake.

Hild added lifeguards conducted a full search of the park and water and Los Angeles County Sheriff’s Parks Bureau were dispatched to search the surrounding area.

The search continued throughout the night and into Monday morning, Hild said. Santa Clarita Valley Sheriff’s search and rescue team was dispatched to set up a search party Monday, and a person on a mountain bike found Arellano near the upper portion of the lake atop a hill.

“The mountain biker called us and said that there was a man fitting the description,” said Hild. “He found the man and called to say he thought he found the guy that we’ve been looking for.”

Los Angeles County Fire Department first responders were dispatched to Castaic Lake at 8:59 a.m. and arrived on scene at 9:06 a.m., according to Charisma Murillo, representative with L.A. County Fire.

Arellano suffers from memory loss, Hild said, and was transported to Henry Mayo Newhall Hospital to receive treatment for head injuries.