A search is underway for a fisherman who vanished in the Gulf of Mexico early Thursday morning.

The Coast Guard says Dennis Grim, 63, is missing and three others were rescued after a boat out of Seminole sank 70 miles southwest of Fort Myers Beach.  

A little before 4 a.m. Thursday, the captain aboard the 37-foot commercial fishing boat, J.U.M.A. sent a distress call via VHF-FM marine band radio channel.

A helicopter crew came to the scene and found James Beeman, Anthony Bertolino, Darren Whalenclinging to life jackets and debris. The men reported Grim missing from their party.  

All three boaters were hospitalized for symptoms of hypothermia.  

Multiple rescue crews have continued searching for the missing boater. 

Stay on WFLA.com for updates on this developing story.