UPDATE (2 p.m.) - CAL FIRE says the search for a possible drowning victim at Lake Nacimiento has been called off.
A worker reported seeing something bobbing in the water earlier in the day, but after an extensive search in the water and from the air, officials say no one was found.
Authorities also went to nearby campsites and checked with people at the lake and say no one has been reported missing.
ORIGINAL STORY: Emergency crews were responding to reports of a possible drowning at Lake Nacimiento Friday.
The call came in at around noon for the area near the marina.
A San Luis Obispo County Sheriff's Office spokesperson says the information was received second hand and units were responding to check it out.
CAL FIRE SLO was on scene as of 12:43 p.m. and said a helicopter was also being used in the search.
No other information was immediately available.