Ballyhoo, also known as a Half beak as Poenskop said, and in some areas known as Balao... although I think there are a few different species....
Damn fine offshore bait, in fact its probably the most commonly used trolling bait offshore rigged either naked, or with a skirt/konahead etc.... they are sailfish candy....
In Central America, places like Costa Rica, Pananma and Gautamala, they are rigged with circle hooks off the beak and dropped back on Sailfish in the spread where the guys have those 100 plus Saily days....
They are pretty plentiful up the North coast, and make damn fine bait!