Troopers say they received a distress call just before noon Sunday from a dive charter boat near the Rock Island Lighthouse in Jefferson County. An unresponsive diver had been brought up from 18 metres. CPR was administered and he was taken to a hospital where he was pronounced dead.
Troopers identified the man Monday as Francois Lacourse of Quebec.
An autopsy is scheduled. Police say the death appears to be related to natural illness.
Dive instructor Anouar Bennaid of Quebec was taken to a hospital for observation due to decompression illness and is expected to make a full recovery.