A man was found dead in Lake Michigan Tuesday near 31st Street Harbor on the South Side.

Authorities were called about a body in the water at 1:48 p.m. in the harbor, 3155 S. Lake Shore Drive, according to Chicago police.

The unidentified man was found near the boat launch, according to the Chicago Fire Department. He was dead at the scene.

It was not immediately clear how long he’d been in the water, police said.

The Cook County medical examiner’s office has not released details about the fatality.