PORTLAND — A body that police divers found on Tuesday morning under Custom House Wharf has been identified tentatively as that of George Manning, 66, a well-known fisherman who was reported missing Monday.

Police sent the body to the state Medical Examiner’s Office in Augusta for positive identification and to determine the cause of death.

Manning was working and living on the fishing boat Northstar, docked at the end of Custom House Wharf. He was last seen about 4:30 a.m. Monday, walking down the wharf toward the boat.

Lt. James Sweatt, the Portland detective who is leading the investigation, said Manning probably was up and about then because the Northstar was expected to go out fishing Monday morning.

Manning was reported missing by his employer, Vincent Balzano, the Northstar’s owner, who arrived at the wharf soon after Manning was last seen, Sweatt said. Manning has been a seasonal deckhand on Northstar for the past 18 years, Balzano said. He described Manning as a “happy-go-lucky” guy who is well known on the city’s waterfront.

“He’s like the mayor of Commercial Street,” Balzano said.

Tim Seekamp, who has known Manning for more than 10 years, said they often have gone to The Dry Dock, a bar in the Old Port, for drinks. Seekamp occasionally has let Manning stay at his home or hired him to do odd jobs.

Manning has been living on the fishing boat since his former home was sold earlier this year, Seekamp said.

“Everyone likes George. Everyone cares about him,” he said.

Seekamp said Manning, originally from South Boston, is nicknamed Shamrock. He is divorced and has two grown children.

“He was very proud of (being from South Boston) and being Irish,” Seekamp said.

Seekamp said it would be out of character for his friend to just take off without telling anyone.

Custom House Wharf is a narrow, cobblestone street off Commercial Street. The Northstar was docked Monday night at the end of the wharf, near Coastal Bait Inc.

Lt. Sweatt said it probably will take a day or two for the medical examiner to identify the body. The cause of death probably won’t be determined until next week, he said, because of the time needed to do an autopsy and toxicology tests.