Published: Jul 17, 2010 1:36 AM EDT
Updated: Jul 16, 2010 10:37 PM EDT

APALACHICOLA, Fla. - Authorities are continuing to search for a Florida Panhandle oysterman believed to have fallen off the side of his boat while out in nearly 100-degree heat.

Witnesses told the sheriff's office that George Sanders fell overboard on Thursday as he was out tonging oysters with two other fisherman. He apparently got back inside, but appeared dizzy and fell again.

Other workers jumped into the water but were unable to find him.

Investigators say they believe Sanders drowned.

The Florida Fish and Wildlife Conservation Commission and law enforcement agencies have been searching the Apalachicola Bay.