How Do These Fishermen Catch Just Tuna? Pole and line is a unique fishing method used to catch tuna and other large pelagic species one fish at a time. When a school of target fish is located, fishermen spray water from the back of their vessel, scattering bait fish onto the water's surface. This creates the illusion of an active school of prey fish. This process, known as chumming, sends the target fish into a feeding frenzy during which they will bite anything they see. Fishers line up along t