Troll in deep fresh water for lake trout, landlocked salmon, walleye, or muskellunge. In salt water, troll with heavy bait for such large fish as marlin, sailfish, or tuna. In either case, the idea is to cover a wide territory in a moving boat, towing live bait or a lure at the end of a long line.
Trolling, like any kind of fishing, requires a balanced rod, reel. and line. In fresh water, the tackle can be as simple as a lightweight casting rod, a revolving-spool reel, and 8-poundtest line. For flies, use a fly-casting rod and reel. Rig the line according to the depth at which you are fishing.
For early-season landlocked salmon just below the surface, use minnows or streamer flies, singly or in combination, with a sinker attached to the line 1 or 2 feet in front of the bait. For lake trout, walleyes, muskies, and late-season salmon that lurk near the bottom, use a three-way swivel with a heavy sinker on one leg; attach the sinker to a light leader that will break if the sinker gets snagged. Use a longer leader for the bait-use a wire leader for sharp-toothed muskies.
Ocean-going tackle generally includes a heavy rod 61/2 feet or shorter and a large trolling reel that can hold up to 1,500 yards of 30-pound-test to 130-pound-test line. The bait can be skipped over the surface or weighted to ride at a depth of about 20 feet.