A Hawaii man told his friend he had hooked a "huge" tuna while deep-sea fishing. He went overboard and is still missing.

Rescuers searched for a third day Tuesday for a Hawaii fisherman who went overboard from a boat after hooking a tuna over the weekend, authorities said. Mark Knittle, 63, of Captain Cook, was fishing with a friend off Honaunau on the Big Island on Sunday, when he hooked an ahi, or tuna, police said.

"The friend heard Knittle say, 'The fish is huge,' then saw Knittle go overboard into the water," according to a police news release.  

The friend tried to grab the line, but Knittle disappeared within seconds, the release said. The friend jumped in but couldn't see Knittle.