When we go Tuna fishing, we use live bait. We mostly use pogies, which are around 12" and blue fish which are usualy a couple pounds. when we use them we put them on a kite system that the main line goes through a clip on another rod with is connected to a kite. When a fish hits the line releases from the clip. The reason you use the kite is to keep the baits back out of the water where the hook is. When the bait is on top it splashes around and attracts the tuna. The reason it works so well is because the tuna cant see the hook or line. Another way of fishing is to tie balloons on the line and give about 50 feet of line from the balloon to the bait, this makes it so the bait is swimming around 50 ft down when tuna usualy stay around.