The hook is usually attached by a line to a fishing rod. A bite indicator such as a float is sometimes used. The rod is usually fitted with a fishing reel that functions as a mechanism for storing, retrieving and paying out the line. The hook can be dressed with lures or bait. Angling is a principal method of sport fishing, but commercial fisheries also use angling methods such as longlining or trolling.
Catch and release fishing is increasingly practised by recreational fishermen. In many parts of the world, size limits apply to certain species, meaning fish below and/or above a certain size must, by law, be released.
The use of the hook in angling is descended, historically, from what would today be called a "gorge." The word "gorge", in this context, comes from an archaic word meaning "throat." Gorges were used by ancient peoples to capture fish. A gorge was a long, thin piece of bone or stone attached by its midpoint to a thin line. The gorge would be fixed with a bait so that it would rest parallel to the lay of the line. When a fish would swallow the bait, a tug on the line would cause the gorge to orient itself at right angles to the line, thereby sticking in the fish's gullet.
The common earthworm is a universal bait for fresh water angling. Grubs and maggots are also considered excellent bait when trout fishing. Grasshoppers, bees and even ants are also used as bait for trout in their season, although many anglers believe that trout or salmon roe is superior to any other bait. In lakes in southern climates such as Florida, fish such as bream will take bread bait. Bread bait is a small amount of bread, often moistened by saliva, balled up to a small size that is bite size to small fish.
Roe is considered an excellent bait for trout, salmon and many other fresh water fish.
Anglers may increase the possibility of contamination by emptying bait buckets into fishing venues and collecting or using bait improperly. The transportation of fish from one location to another can break the law and cause the introduction of fish alien to the ecosystem.
Laws generally prohibit catching fish with hooks other than in the mouth (snagging or foul hooking) or the use of nets other than as an aid in landing a captured fish. Some species, such as bait fish, may be taken with nets, and a few for food. Sometimes, (non-sport) fish are considered of lesser value and it may be permissible to take them by methods like snagging, bow and arrow, or spear. None of these techniques fall under the definition of angling since they do not rely upon the use of a hook and line.
The practice of catch and release is criticised by some who consider it unethical to inflict pain upon a fish for purposes of sport. Some of those who object to releasing fish do not object to killing fish for food. Adherents of catch and release dispute this charge, pointing out that fish commonly feed on hard and spiky prey items, and as such can be expected to have tough mouths, and also that some fish will re-take a lure they have just been hooked on, a behaviour that is unlikely if hooking were painful. Opponents of catch and release fishing would find it preferable to ban or to severely restrict angling. On the other hand, proponents state that catch-and-release is necessary for many fisheries to remain sustainable, is a practice that that generally has high survival rates, and consider the banning of angling as not reasonable or necessary.
In some jurisdictions, in the Canadian province of Manitoba, for example, catch and release is mandatory for some species such as brook trout. Many of the jurisdictions which mandate the live release of sport fish also require the use of artificial lures and barbless hooks to minimise the chance of injury to fish. Mandatory catch and release also exists in the Republic of Ireland where it was introduced as a conservation measure to prevent the decline of Atlantic salmon stocks on some rivers. In Switzerland, catch and release fishing is considered inhumane and will be banned beginning in September 2008.
Barbless hooks, which can be created from a standard hook by removing the barb with pliers or can be bought, are sometimes resisted by anglers because they believe that increased escapement results. Barbless hooks reduce handling time, thereby increasing survival. Concentrating on keeping the line taut while fighting fish, using recurved point or "triple grip" style hooks on lures, and equipping lures that do not have them with split rings can significantly reduce escapement.
Experiments done by William Tavolga provide evidence that fish have pain and fear responses. For instance, in Tavolga’s experiments, toadfish grunted when electrically shocked and over time they came to grunt at the mere sight of an electrode. Additional tests conducted at both the University of Edinburgh and the Roslin Institute, in which bee venom and acetic acid was injected into the lips of rainbow trout, resulted in fish rubbing their lips along the sides and floors of their tanks, which the researchers believe was an effort to relieve themselves of pain. These tests have been dismissed by some defenders of angling, as fishing hooks do not contain acid or venom. These tests have also been criticised as hypocritical in that they themselves cause apparent distress to fish. One researcher argues about the definition of pain used in the studies.