A common method for fishing marlin is to drift live mackerel baits deep amongst baitfish schools. The rigging that works best is to attach a 6-10 oz torpedo sinker with a small rubber band to a snap-swivel which is attached to 10-15' of #100 leader. On the hook up, the rubber band will break free and not foul on the leader. Another tip is to use mackerel baits that are healthy and strong swimmers - this live bait action will trigger a strike much better than a weak swimming bait. Multiple hook-ups and double digit catch and release days are common.