When chunk fishing for tuna, you must bring the fish to your bait. Because you will be fishing in depths of several hundred feet, it will take more than a single bait to attract the attention of tuna. Ideally, try to locate working boats that are dragging the tuna grounds for scallops. The draggers bring up tons of discarded fish-like skates, summer flounder and small cod. As the workers on the scallop boats toss the discards back into the water, tuna take advantage of the opportunity for an easy meal and pick off the stunned fish as they sink through the water column.
The Best Bait
Frozen sardines, butterfish and mackerel are all good tuna baits. If you can make a trade with the scallop boat deckhands for fresh bait, your chances of catching fish will go way up. These men are at sea for a week at a time. Offer them beer for some discards and you can usually get a few baskets full of discards. The trade is made while the boats are underway, and you can hang the beer on the yard arm of the scallop boat.
Pulling the Tuna Away
Now that you have your bait, it's time for action. Position your boat behind the dragger and begin chumming hard. If you keep throwing chum in the water, the tuna will stay with you as the dragger pulls away. If you do it right, you will see the tuna flash through your chum slick.
Deploy Your Bait
Now that you have tuna in your chum slick, it's time to put out some hooked baits. Tuna have incredible vision and can detect monofilament lines thicker than 30-lb. test without difficulty. They also will shy away from a chunk with the hook protruding from it or a chunk that does not sink naturally through the water. If you want to catch tuna on your chunk bait, your leader should be fluorocarbon line and not heavier than 30-lb. test. Bury the hook completely inside the bait, hiding it completely if possible. To make the bait sink naturally through the water, put your fishing rod in the holder. Put your reel in free spool with the clicker on and pull off 15 to 20 feet of line. Throw your chunk bait in the same area you are throwing the chum and begin pulling line from your reel. The idea is to let the bait sink without pulling on the line. If the bait pulls against the line, it will make a sharp turn in the water, alerting tuna that something is wrong.
When a tuna takes your bait, you will know it. Wait several seconds while the line screams off your reel. Point your rod directly at the fish and begin reeling. When the line comes tight, reel some more before setting the hook. Set your hook two or three times, but not more than that. Be prepared to start the boat and follow the fish if necessary.