Trolling depth is the water depth where a fishing lure or baited hook is dragged behind a boat. While trolling for fish, a key strategy is controlling the trolling depth to where the fish are schooling. Different species of fish school at different depths, and those also change at different times of year.
How is trolling depth controlled?
Trolling depth can be controlled by using devices like downriggers, fishing lure depth planers (such as Davis' Fish Seeker), and strategies like "The Rule of Fives".