A fishing line is a flexible, high-tensile cord used in angling to tether and pull in fish, in conjunction with at least one hook. Fishing lines are usually pulled by and stored in a reel, but can also be retrieved by hand, with a fixed attachment to the end of a rod, or via a motor. Fishing lines generally resemble a long, ultra-thin rope, with important attributes including length, material, weight and thickness. Other factors relevant to certain fishing environments include breaking strength, knot strength, UV resistance, castability, limpness, stretch, abrasion resistance, and visibility. Traditional fishing lines are made of silk, while most modern lines are made from synthetic polymers such as nylon, polyethylene or polyvinylidene fluoride ("fluorocarbon") and may come in monofilament or braided (multifilament) forms. Terminology Fishing with a hook-and-line setup is called angling. Fish are caught when one are drawn by the bait/lure dressed on the hook into swallowing it in whole, causing in the hook (usually barbed) piercing and anchoring into the mouthparts, gullet or gill, resulting in the fish becoming firmly tethered to the line. Another method is to use a straight gorge, which is buried in the bait such that it would be swallowed end first, and the tension along the line would fix it cross-wise in the quarry's stomach or gullet and so the capture would be assured. Once the fish is hooked, the line can then pull it towards the angler and eventually fetch it out of the water (known as "landing" the fish). Heavier fish can also be landed with a landing net or a hooked pole called a gaff. Trolling is a technique where one or more lines, each with a fishing lure at the end, is dragged through the water. Trolling from a moving boat is used in big-game and commercial fishing as a method of catching large open-water species such as tuna and marlin. Trolling can also be used when angling in freshwater as a way to catch salmon, northern pike, muskellunge and walleye. The technique allows anglers to cover a large body of water in a short time. Longline fishing, also known as a trot line is a commercial fishing technique that uses many baited hooks hanging perpendicularly from a single line. Snagging is a fishing technique where a large sized hook is used to pierce the fish externally in the body (like a gaff) instead of