The Clarkspoon MT-0RBMS Mackerel Tree Rig is an East Coast and Florida favorite that's deadly on Spanish Mackerel, Bluefish and other game fish. The Mackerel Tree Rig is used while trolling. You can either drag it on top of the water or connect it to a planer or trolling sinker for depth. The swivel ties to the line from the rod or to the leader coming from the bag of the planer.