trolling lines. The trolling lines are fishing lines with natural or artificial baited hooks trailed by a vessel near the surface or at a certain depth. Several lines can be towed at the same time using outriggers to keep the lines apart. The lines can be hauled in manually or by small winches. A length of rubber is often included in each line as a shock absorber. The trolling line is towed at a speed depending on the target species, from 2.3 knots up to at least 7 knots. Trollers range from small open boats to large refrigerated vessels 30 meters long. In many tropical artisanal fisheries, trolling is done with sailing canoes with outriggers for stability. With properly designed vessels, trolling is an economical and efficient way of catching tuna, mackerel and other pelagic fish swimming close to the surface. Purpose-built trollers are usually equipped with two or four trolling booms raised and lowered by topping lifts, held in position by adjustable stays. Electrically powered or hydraulic reels can be used to haul in the lines. Commercial trolling for tuna is more successful near offshore banks than in open water areas, and is also enhanced in the vicinity of a fish aggregation device (FAD). Historic trolling Historically, in Alaska, hand hook and line trolling were used commercially to catch king and silver salmon in salt water. This method required minimal gear-boat, lines and hooks—and was used to catch fish that were still feeding in open water before returning to spawn. Trolling was very successful in southeast Alaska and historically the catch was used by the fresh and mild-cured fish packing industries. Power boats located near feeding grounds conducted most of the trolling. Each boat had four to ten lines, extending from tall poles hung outboard when fishing; each line carried several hooks, with heavy lead sinkers and spoons or baits as lures. Trolling lengthened the fishing season, allowing fishermen to fish in early spring before spawning runs. See also Longline fishing Notes References Merriam-Webster definition 2a: "to fish by trailing a lure or baited hook from a moving boat" Instructions in trolling Hall P (1992) Trolling for Gamefish – Some Basic Techniques Fishnote No. 10. Northern Territory Government, Australia. Schultz K (2009) Ken Schultz's Essentials of Fishing: The Only Guide You Need to Catch Freshwater and Saltwater Fish John Wiley and Sons. Trolling Fact Card Seafood Watch. Retrieved 23