Rescue personnel were at South Lido Park in Sarasota Saturday night after reports of a possible drowning, police say.
Sarasota County received a call at about 6:50 p.m., that a 19-year-old man was swimming with a friend 50-75 yards offshore.
The pair became exhausted and decided to head back to the beach, a news release said.
The friends became separated. The missing man was last seen struggling in the water by his friend, who made it to shore.
A search and rescue mission was begun by the Sarasota Police Department with the assistance of the U.S. Coast Guard and a helicopter from the Sarasota County Sheriffs Office, according to a news release.
After searching for several hours and with inclement weather moving in, the search was shut down for the night and will resume 6:30 a.m. Sunday morning by a team from members of the Sarasota Police Department, Sarasota County Sheriff's Office, Florida Fish and Wildlife Commission and the Coast Guard.
The Coast Guard and units from the Florida Fish and Wildlife Commission were remaining on scene through the night, the release said.