The Contra Costa County Sheriff's Office suspended its search for a missing fisher off Big Break in the eastern part of the county Sunday afternoon. The search is likely to continue Monday, a Sheriff's Office spokesman said.

Harry Lee, 51, of San Francisco, is presumed to have fallen off a 20-foot recreational fishing boat sometime Saturday. The boat was found adrift in the Delta about 2:15 p.m. by other boaters.

Its motor was still in the water. Fishing poles and food were found aboard. The U.S. Coast Guard believed the boat had been occupied recently.

Lee was believed to have been wearing a manually inflatable lifejacket, Coast Guard Lt. Simone Mausz said. His truck was found in the parking lot of Lauritzen's Yacht Harbor in Oakley.

Sheriff's spokesman Jimmy Lee did not say whether the victim is believed to be dead.

"We're probably going to be out in the water searching (Monday)," he said.

Two Coast Guard boats, a Contra Costa sheriff's marine unit and a helicopter took part in the search Saturday and the Coast Guard called off its search Saturday night after scouring about 46 square nautical miles, spokesman David Font said.

"We have no more leads to investigate," he said.

Roman Gokhman covers public safety. Contact him at 925-945-4780. Follow him at Twitter.com/RomiTheWriter.