Tuna Traps were designed for when Tuna are very line-shy. There are days that the only way you can get a hook-up is dropping down to leaders as light as 30lb test. You get more bites with this light leader but will land very few tuna due to the leader being so light. On days like this is when Tuna Traps are required.
These Traps are made up with 13" 275lb test cable and a 220lb test AFW Mini stainless swivel. The cable is coiled and held in place on the shank of the hook with band. The entire Trap is hidden inside the bait and a light leader is attached to the swivel. On a run-off and hook-up, when the hook catches and sets up the drag tension will pull the cable out of the band and out of the Tuna. Now you have 12" of 275lb test cable in its mouth rather than light leader.
Tuna Traps are not needed every day but there are days you'll wish you a had a couple in the tackle drawers.