Dry fly fishing

Fly fishing for trout can be done using various methods and types of flies. Trout mostly feed near the bed of the stream, where wet flies and especially nymphs are used.^{[citation needed]} Trout may also come to the surface to feed, typically on winged insects following hatch events.^[1][2][3] Particularly during the summer months, trout also often feed on terrestrial insects such as ants, beetles and grasshoppers when they fall onto the water surface.^[4] However, midges hatch year-round, and so smaller dry flies may be used successfully outside of the summer, when trout may favor caddisflies or mayflies.^[5]

Salmon may also occasionally bite a dry fly lure in specific scenarios where other flies would not be as useful, such as when the fish is in shallow water during very sunny conditions.^[6]

The aim of dry-fly fishing is to mimic the downstream drifting of a real fly on the surface of the water, and is sometimes regarded as more difficult than other fishing techniques.^[7] Dry-fly fishing uses a line and flies that float. They are joined by a fine 3 to 5 meters long leader, typically of nylon monofilament line, which is tapered so that it is nearly invisible where the fly is knotted, and the angler can replace the last meter or so of nylon as required.

J.W. Dunne recommends that trout are used to their prey approaching them in the current, and such an optical phenomenon should be mimicked by a fly lure.^[8] Trout fishermen therefore prefer to begin downstream of the fish's suspected lie and work upstream into the current. Trout can see a wide area around them, so the angler must stay not only downstream of the fish, but also as low to the ground and as far from the bank as possible, moving upstream with stealth.^{[9][failed verification]}

Trout tend to strike their food at current "edges", where faster- and slower-moving waters mix. Obstructions to the stream flow, such as large rocks or nearby pools, provide a "low energy" environment where fish sit and wait for food without expending much energy. Casting upstream to the edge of the slower water, the angler can see the fly land and drift slowly back downstream. The fly should land softly, as if dropped onto the water, with the leader carefully positioned to control the drift through the strike zone and present the fly to the intended target without making the fish aware of the angler's presence.

A notable challenge in stream fishing is accurately placing the fly lure (e.g., within inches of a protective rock) to mimic the behaviour of a real fly. When done properly, the fly appears to float in the current with a "perfect drift" as if not connected to a line. The angler must remain vigilant for the "take" in order to be ready to raise the rod tip and set the hook.

Due to rivers having faster and slower currents often running side by side, the fly can overtake or be overtaken by the line, thus disturbing the fly's drift. Mending is a technique whereby one lifts and moves the part of the line that requires re-aligning with the fly's drift, thus extending the drag free drift. The mend can be upstream or downstream depending on the currents carrying the line or fly. To be effective, any mending of the fly line should not disturb the natural drift of the fly. Learning to mend is often easier if the angler can see the fly.^[10]

Lastly, due to the social nature of fishing it is common for parties to impinge on perceived boundaries. Etiquette varies by locality, but stomping through streams, "slapping and stripping", and high-holing are generally frowned upon.

Compared to "wet" fly fishing, bites on dry fly lures are highly visible.^[11] Many anglers prefer dry fly fishing because of the relative ease of detecting a strike and the gratification of seeing a trout strike their fly. Nymph fishing is easier; it doesn't require "angling" skills associated with learning various casting techniques.

Once a fish has been caught and landed, the fly may be wet and no longer float well. Flies can sometimes be dried by "false" casting back and forth in the air. With care, a small piece of reusable absorbent towel, an amadou patch or a Chamois leather may be used. A used dry fly which refuses to float may be replaced with another similar or identical fly while the original dries out. After drying, a fly may need a fresh application of water-repellent fly "dressing" liquid.

A dry fly is designed to land softly on the surface of the water without breaking it and becoming wetted, but does not necessarily need to be buoyant. They are often oiled or treated with another water repellent. Dry flies are used in freshwater.^[12]

Dry fly lures can be separated into two broad categories: imitations and attractors. Imitations typically represent the adult form of an aquatic or terrestrial insect, such as the elk hair caddis, a caddisfly imitation.^[13] The small Baetis (blue-winged olive, BWO) is another common fly, for which several imitators have been designed. Attractor fly lures may not directly mimic an insect, but are easily seen used to provoke the attention of a target fish. Attractors are often best used in low clarity water.^[14]

A translucent fly seen from underneath with sunlight shining through it looks very different to a fly when out of the sun. Some dry flies, especially imitators, are especially designed to mimic this effect. J. W. Dunne developed a technique of painting the shaft of the hook white and wrapping it in translucent artificial silk, which he then oiled.^[9][15]

Salmon flies, such as the Parks' Salmonfly, are usually larger than trout flies.^{[citation needed]}

The following is a list of the more popular dry flies for trout:^[16][17][18]

Dry fly fishing first became a serious sport in the 19th century, with the publication by Frederic M. Halford of two books: Floating Flies and How to Dress Them and Dry-Fly Fishing in Theory and Practice. His artificials were designed to imitate real flies but they only did so under limited conditions. This led J. W. Dunne to develop a theory of trout vision, and from it a series of imitators intended for use in sunny weather, which he published in 1924 as Sunshine and the Dry Fly.

Meanwhile G. E. M. Skues had begun promoting wet nymph fishing. He went on to popularise the use of attractors, designed to goad the fish rather than to fool it. Skues' approach outraged the traditionalists who favoured the dry fly and in 1938 the Flyfishers' Club staged what amounted to an inquisition hearing against him. However Skues' approach proved more effective in the majority of situations.^[20]

Synthetic materials now play a significant part in the design of modern trout flies. Materials like poly yarn, which is less dense than water and therefore remains buoyant, and kapok, which can be dyed commercially using modern techniques, or other materials, including ice dubbing, have expanded the range of available fly-tying options. In addition, for stillwater competition chenilles and fritz materials are now used in many new flies, such as blobs. ^[21]