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Fly Fishing 101, Part 25

Size Does Matter

There was a question from a reader on what size flies to use when. The particular question had to do with nymphs - but it applies to all of the flies generally used for fly fishing. You match the size of the fly to the natural insect. How can you tell? Find out what the insect of the day is. Turn over some rocks in the water. Look at what insects are on those rocks. Carry a gold-fish type net and try to scoop up what is in the water.

If you are fishing with a buddy, make a small seine, about an arm's reach wide. You can make it with a piece of window screen stapled between two sticks. Have one person hold the seine, spread out, in the current downstream, and walk toward the seine shuffling your feet. (Don't walk too far shuffling you feet, it does dislodge and kill insect life, this practice is frowned on since it has been misused.) Then take the seine out of the water carefully and examine what you have collected. The insects will fall into either caddis, mayfly or stonefly categories. Go back and read sections 13 - 18 on the insects here if you aren't sure you know the differences.

Once you have identified the insect, match your fly to the size of the insects you have found. If you have several sizes of the same insect, the larger insect is the closest to hatching. Start with the largest sizes you can match, and if you don't have interest from the fish in those, work your way down in size to smaller nymphs. Remember the size of flies is in reverse of shoe sizes, the larger the number the smaller the fly.

Insects who have emerged from their nymphal state are becoming flying insects. Here, match size and color as closely as possible. I have taken my nippers and cut down hackle, tails, whatever to get a fly down closer to the size that is flying, or mashed down and rubbed some river mud on a dry fly to make it just barely float in the surface film to resemble an emerger.

Most of all, be observant! Instead of getting geared up the instant you park your rig, walk down to the water, find a place to sit, and watch the activity for five minutes. Longer is probably better, but being anxious to fish, even five minutes seems like a long time. Watch for birds working. Birds swooping low over the stream is sure proof of a hatch, mating flight, or spinner fall. Birds working higher may indicated a mating flight is happening - and later, toward evening a spinner fall of the females laying their eggs, and the exhausted males falling to the water on the water will bring the fish up to feed.

Look for any fish activity. Are there rising fish? How about bulging fish? Those are fish which are taking nymphs or emergers before they reach the surface. The fish don't break the surface, but make a small hump or bulge in the water. Eventually, those insects will make it to the surface and you will have a hatch - and a place to use dry flies.

The successful fly angler is watching under the water, on the water, the sky above the water, and checking the stream-side brush and trees for evidence. Evidence to help him make educated choices on what fly to fish.~ DB

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