Most of the time, the fishing line used for sport fishing has a breaking strain less than the maximum force the fish can apply to the line. The fishing reels therefore have sophisticated, adjustable drag mechanisms which allow the line to escape if the fish pulls on it, but keep the specified tension on the line. When hooked, most fish will circulate in different directions, and when they are not pulling away from the boat the fisherman can take the opportunity to reel in some of the line. Eventually, if the fish tires and has not broken the line, they will be reeled in; however, the challenge does not end there. Hauling a heavy, powerful, and still very much alive fish on board the boat represents a considerable challenge, unless the fish is tagged and released. Strategies include: gaffing, pulling it in with one's hands, or a net for smaller fish.