The sedge fly – its life and fishing the artificial

Words by:
Barry Grantham
Featured in:
September 2021

The sedge fly, or caddis fly, belongs to the order of Trichoptera. It is sometimes referred to as a roof-winged fly. The sedge is mainly an aquatic fly, having a larval and pupal stage in the water. There are some species that are terrestrial in the UK but to the angler it is the aquatic species that are of interest, as Barry Grantham explains.

The sedge has a complete life-cycle: egg, larva, pupa, adult. The females lay their eggs on the water by dipping their bodies into the water’s surface film. Some females use bankside vegetation and rely on rain or dew washing the eggs into the water. The eggs that are laid by the female are covered in a sticky gel-like substance to protect the eggs from predators.

The eggs sink to the water’s bottom and the larvae hatch out. Hatching occurs throughout the year but most species hatch in late summer. When the larvae hatch, to protect themselves, they construct a protective shell. This is made from a variety of materials – sand, gravel, minute stone and pebbles and vegetable matter. The larva, when ready to pupate, seals its protective shell and changes to the pupa.

The pupae have jaws that they use to break free from their protective shell. The hatching pupa, or to be more accurate the hatching adult, climbs up weed to get to the water’s surface.

When the hatching sedge gets to the water’s surface or dry land, some fly straight off while others skim across the surface of the water. We anglers call this ‘skittering’.

The hatched sedge will spend from a day or so to a month as a winged adult sedge. The fly’s mouthparts are made so as to take fluids and takes in rain droplets, dew and nectar from plants.

The sedge’s life-cycle lasts about one year and it is mostly the larva that spends winter under the water’s surface.

The adult sedge has four wings and these wings are covered with tiny hairs, hence the name Trichoptera – ‘trichos’ meaning appertaining to hair and ‘ptera’ meaning wing. They are weak flying insects and tend to shun the daylight hours. During this time they will spend their time in bankside vegetation until the sun has gone below the skyline. As dusk approaches, the sedges flutter from the bankside vegetation and the mating process takes place. The female is the larger of the two flies and the eggs usually mature a day or so after mating.

The ideal place to fish a caddis larva in still water is from the bank, as the larva will most likely be found close to the bank in the weeds and vegetation. Another good place is where a stream or dyke enters the water or where there are sunken hedgerows.

You do not need sunken lines to fish the sedge larva; a floating line with as long a leader as you can manage will work. Ten to 15 feet should be okay but in really windy conditions a shorter one would suffice. The imitation larva is cast out and allowed to sink to the bottom; it is then allowed to move around with the natural movement of the water – or if no movement, retrieved very slowly using a figure of eight retrieve.

Fishing the pupa is very much the same as the larva. A long leader is again used. The artificial larva is allowed to sink to the bottom but this time, a retrieve called sink and draw is used. Slow, long pulls are made on the line; this causes the imitation to rise and fall in the water making it look like the pupa getting to the surface of the water. More flies can be added to droppers on the leader thus presenting the artificial pupae at different depths.

Fishing the adult fly is one of the most exciting methods of fly fishing. It is not difficult to do. I use three methods to fish the artificial dry sedge.

The first is to cast the fly out and just allow it to sit on the water. If there is a nice ripple or wave on the surface, all the better. Or I try to find calm water with some ripple and place the fly where the two meet. Trout always swim along where calm water joins a ripple. It is a food trap.

The second is this: I use a pattern that is dunked in a floatant to help it stay on the surface. The fly is cast out, preferably into a good ripple or wave on the water’s surface and then retrieved with long pulls on the line to make the fly skim across the water’s surface – skittering. Savage takes by a trout are experienced using this method.

My third method is to use two artificial flies. An adult sedge imitation is tied on the end of the leader. This fly does not have any floatant added so that it will just sink into the surface film. Another sedge fly is added about four feet above the end fly. Floatant is added to the fly so that it will not sink. The flies are cast out and slowly retrieved. A deadly method for fishing sedge fly patterns.

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