The CDC Detached Body Mayfly

The CDC Detached Body Mayfly

From Europe comes an inventive mayfly pattern with an easy-to-make extended body and a floats-like-a-cork CDC wing.

  • By: Barry Ord Clarke
CDC Detached Body Mayfly

My friend Martin and I are fishing buddies who pay homage each year to a small mountain area in southern Norway. The only mayflies to be found there of interest to fly fishermen are Leptophlebia vespertina and Leptophlebia marginata; fortunately, these insects are in such great numbers that the fishing can be fantastic during a hatch, if your timing is right.

Our first day to the area last season was, to say the least, disappointing. No-disastrous! We were met by the worst weather imaginable and could only manage a couple hours of waving carbon. We retired to the fishing lodge and indulged in 12-year-aged Scottish culture, checking for the morning's weather forecast and admiring the monster brown trout and moose trophies that adorned the walls of the lodge.

The next morning we were out and fishing at daybreak. The wind had dropped but there was still a light rain, and heavy black clouds hung low in the sky, hiding the nearby mountains.

We began fishing at lake Kattevald. This is one of the area's most interesting spots. It's essentially a large bay of lake tern that has been cut off from the main lake by floating mats of peat and grass that can be blown around in a strong wind, changing the layout of pools and smaller lakes. Walking on the mats is like walking on a large grass-covered water bed.

Martin began fishing with the fly that produced the most fish for him on our previous visit, a CDC Detached Body Mayfly, one of my patterns. It didn't take long before I heard him shout "Fish on." His 5-weight rod was bent in half as he tried to back his way out from the middle of a raft of floating peat. The fish managed to round this floating mat twice before Martin brought it to terra firma. The first Luksefjell-region brown trout of the year was in the net. It was a fish of no less than 600 grams (or about a pound and a half in avoirdupois weight).

Over the next few hours, we explored the other small lakes of the area, and the last part of the day produced several more trout up to, and just over, the kilo mark, most of which fought with just as much passion and determination as the first. Even though I had fished these lakes many times, I was still amazed by the sheer fighting power and strength of the fish-and by their willingness to take the CDC Detached Body Mayfly.

CDC Detached Body Mayfly

Hook: Mustad 94840 sizes 10 to 16
Body form: Upholsterers needle
Thread: Dyneema
Tail: Peccary or moose hair
Wing: Cul de canard
Body: Flyrite dubbing

This is an effective mayfly pattern that, with a little practice, fly tiers of any skill level can master.

Born in England, Barry Ord Clarke is a freelance photographer and writer who lives in Skien, Norway.

By changing the size and color of the pattern, you can match most mayfly hatches.
The small fibers of the CDC, in combination with the natural water-repelling oils of the duck that it came from-the abbreviation CDC is for cul de canard, and the feathers come from a duck's rump region-trap small pockets of air that are just enough to keep the hook afloat and the body half submerged. It's always better to use CDC that hasn't been dyed, as the dying process, particularly warm-dying, removes the natural oils in the feathers and reduces its water-repelling qualities.
The CDC Detached Bodied Mayfly is best fished as a dun, but can also be fished as a spinner, with a little adjustment to the tying and positioning of the wing, particularly when fish are selective. (Tie it in a spinner style.) When mayflies emerge into duns, this pattern can be fished with an intermediate line. After presenting the pattern, with your rod tip close to the water, let your intermediate line sink a little, and then mend the slack in your line and lift your rod tip, making the fly dive following the curve of your intermediate line. When you stop the lift of your rod tip, the fly will stop diving and rise, just as a natural emerger does, and pop onto the surface. This can be a deadly effective method.
Other times, mayfly nymphs swim to the surface, shake their nymphal case free and sit on the surface for a short while like small sail boats. These are easy pickings for feeding fish. Use a similar presentation with your fly.
In still-water fishing, trout can be extremely selective when feeding on mayflies; they have good time to check them out before sucking them in. This is particularly true in calm conditions when the surface is as flat as a mirror. Under these circumstances, it is important to remember to sink your leader. It won't help presenting the right pattern to a trout that can see your tippet.
In rougher conditions, or on the surface of a river's running water, your tippet will be less visible and the trout also have less time to examine your chosen fly. Finally, in lower-light fishing situations, I use markers to give my mayflies a nice bright CDC wing for better visual contact from a distance.

CDC Detached Body Mayfly

Hook: Mustad 94840 sizes 10 to 16
Body form: Upholsterers needle
Thread: Dyneema
Tail: Peccary or moose hair
Wing: Cul de canard
Body: Flyrite dubbing

1 Place an upholsterer's needle in the vise. You can use a regular straight needle for this if you would like to make a body that lies flat in the surface like a spinner.
2 Apply a little wax to the area of the needle on which you will make the detached body. This will make removing the body much easier, later.
3 Run a foundation of thread on the needle; this will be the mayfly-body base. I use Dyneema tying thread, a multi-filament thread that if spun in the bobbin counterclockwise opens the filaments so the thread flattens on the hook shank. If spun clockwise, the filaments twist together and reduce the size of the thread down to 16/0. This thread comes only in white, but can be colored with waterproof pens.
4 Select three long peccary fibres, and tie them in as shown at right. I like to use peccary for the larger mayflies and moose hair for the smaller patterns. It's a good idea to choose fibres that are long enough to run the full length of the body, and then some, which will make the body stronger and more durable.
5 I use is Flyrite dubbing, but you can use any synthetic dubbing that has long, fine fibers. (The long fibers make is easy to wrap the dubbing around the needle; they also strengthen the body.) If you use a straight needle, once you have tied in the tail you can tie in the dubbing, remove the needle from the vise and roll the needle between the finger and thumb of one hand while you feed on the dubbing with your other hand; this makes superfine, even bodies.
6 Add the dubbing to your tying thread and begin at the base of the body. Make sure that the dubbing is applied firm and even but not too tight, which would make it difficult to remove the finished body.
7 Once you've made a couple of turns of dubbing, you can apply a little superglue to the foundation of tying thread. The wax that you applied earlier will stop the thread from adhering to the needle.
8 Now dub the whole body. Make sure you get the correct body taper, and the right length, for the mayfly species you aim to imitate.
9 Tie off the thread with two or three half hitches. Place your thumb and index finger on each side of the body and carefully loosen it from the needle by rolling it between your fingers and easing it off. The dubbing, tying thread and glue have merged into a body tube.
10 Secure your hook in the vise and attach the tying thread. You can now tie on the body halfway down the hook shank, as shown in the photo.
11 Once the body is secure, apply a little dubbing on your tying thread, and dub the rest of the rear of the body. Take your time and get the proportions correct.
12 Select a bunch of long CDC fibers and tie these in almost Paradun-style to form the wing.
13 Once the wing is secure, dub the rest of the mayfly body. When the body is finished, taper off the dubbing to form the head.
14 Whip-finish and clip the tying thread. And there you have it, the finished CDC Mayfly.
15Here's a frontal view (at right) of the CDC wing.

Born in England, Barry Ord Clarke is a freelance photographer and writer who lives in Skien, Norway.