Salmon fly size depends on the fly tyer!

Fishing instructor, fly fishing tuition and fishing trips based in Scotland. Salmon and trout fishing advice, flies and articles.

Salmon fly size your choice! (article and pictures by Ally Gowans)

Towards the tail of the pool the smooth water begins to slip by faster, accelerating and shallowing as it goes. The presence of submerged boulders is indicated by vee wakes on the surface some distance downstream of their locations and in this smooth flow travelling fish will find comfort and rest for a time after their sojourn through the rough, turbulent water below. If I haven’t already reduced the size of my fly I may now choose to do so as the glassy water will make it easier for the fish to observe the fly and if it is too obvious and the fish has seen it several times before the fly has trespassed into its tolerance zone it may well be ignored, the surprise and novelty of this strange artifice gone, it has become ignored, part of the scenery. If on the other hand I have chosen well and presented the fly carefully in a way that the fish is suddenly confronted, conscious of this object fleetingly passing it may well decide to investigate more seriously. That is why we move at least a step between casts and sometimes it pays to advance further, fishing a bit faster and perhaps resting the pool before fishing it again maybe with a change of fly or approach rather than boring or worse still frightening the fish by thrashing the same piece of water.

If the water had been clear and or lower, I would probably have selected smaller flies but my approach would have been fairly similar, imagining how the fly is presented and endeavouring to show the fish enough but not too much of it. We tend to be comfortable conversing fly sizes to each other by stating hook sizes but really there is no sure way of knowing what that actually means, hook appearances and styles differ widely and flies can be dressed smaller or larger than the hook size might suggest let alone the huge variety of shapes and styles of fly patterns. In 1964 Lee Wulff and friends came up with the idea of the “Sixteen-Twenty Club” the qualification for membership is to catch a 20lb salmon on a size 16
size 16Prefontaine fly
#16 hook but the dressing is more like #10
Prefontaine dry fly
fly hook, Alain Prefontaine became the first member of the club on the evening of the very day that it was formed using a new fly that Lee had tied for the purpose and so in his honour it was christened “Prefontaine”. I attempted to tie something similar to the example illustrated in Lee’s book “The Atlantic Salmon” to demonstrate how misleading hook size can be. It is of course a skater and quite similar to what might be used as a dapping fly in Scotland but its dressing represents a much larger fly than a #16 maybe a size 10 if not a size 8! At the other end of the spectrum we have the low water style of fly where the dressing occupies no more than about half of the length of the hook shank.  To illustrate that I have tied three flies on Daiichi “#5 Spey Fly Hooks” although the hooks are identical each “fly” is a different size, I would have no hesitation is using any of these and would choose which according to the dressed size rather than the hook perhaps better described as its “presence” in the water.

Hook measurement
Hook measurement

Salmon hook sizes are supposed to be derived from the length between the bend and the eye (excluding the eye) in inches. (I have included approximate conversion to millimetres for those who prefer the metric sizes.) The size 5 Daiichi hooks that I used measure 1¼ inches which would make them size 1 according to the standard scale! Partridge code M size 2 is close to the scale length of 1 1/8 and its gape is similar to the Daiichi size 5. I measured a small sample of other hooks and there appears to be lot of variation between different styles and manufacturers. So it would be perfectly possible to buy flies tied on “same size” hooks that are clearly of different size. This is less of a problem if you buy over the counter because you see the goods before purchase but it could cause confusion for online buyers who end up with flies larger or smaller than intended.

Salmon Hook Sizes (standard irons)


































Note that the sizes increase by 1/16” up to a size 3, larger sizes up to 2” increase in 1/8” steps, and beyond that the intervals are ¼” in the sequence 2, 1, 1½, 1/0, 2/0, 3/0, etc. up to 10/0. Many different styles of salmon/steelhead fly hooks are available and as shown many of those don’t comply with the traditional size methodology and in some cases curved hook shanks don’t facilitate tying full length bodies. Gone are the days when hook size was a clear indication of the fly size!

tube flies - same tube length different result
Three tubes of same length but different dressing styles.

Similarly tube flies can be usefully be made in a variety of styles and so we expect that a 1 inch Willie Gunn will have certain proportions, we also expect that a 1 inch Sunray will have proportions that are quite different. So if we know the size of the hook or tube and we are familiar with the fly pattern relating the size of the fly, or if you like its “presence” becomes much easier to imagine. For summer fishing my “go to” flies in addition to those mentioned are Cascade, Ally’s Shrimp, Stoat’s Tail, Silver Stoat’s Tail and a Sunray type tube for use as a streamer. Regards sizes I would like to have a few tied on “standard” hooks #6 for high water, a supply of sizes 8, 10, 12 and a few smaller flies for extreme low water. I also carry a selection of small bore plastic tube flies suitable for fishing conventionally or hitching.

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Copyright 2007 Alastair Gowans AAPGAI and FFF Master and THCI, APGAI. All rights reserved.