The man is believed to have gone overboard sometime around 6:30 a.m. His fellow boaters reported that they hadn't seen him since they were 12 miles from Moss Landing, Coast Guard Station Monterey Executive Officer John Suckow said.
A Coast Guard search of the water within a 10-mile radius of where he was last seen is under way, involving as many as two motor lifeboats, an 87-foot cutter and helicopters, Suckow said.
The three other fishermen on board have been assisting in the search for most of the morning and early afternoon, Suckow said.
The missing fisherman was wearing bright orange rain gear, which makes the situation more "hopeful," Suckow said. He added that there is good visibility today.
Suckow said it appears that the fishing boat left Monterey and made a port call in Moss Landing early this morning before the fisherman went missing.
He advised boaters, "We always recommend wearing life vests."