Size relations

Size relations

Viking Lars | Saturday, 13 March 2021

Fly size… A difficult subject to discuss. Not from a normative point of view as such: Measure the fly against a ruler, both length and girth and you have absolute measurements. But there’s more to fly size than that, I think. I think fly size should be more discussed than fly pattern. I believe that fly size matters more than the particular pattern in many situations.

Not all, but many. For shy, picky trout and grayling, size, type and colour of fly can make the difference between a blank and a catch. The same in calm, clear water in the salt with sea trout feeding in the shallows. Here fly size is king - whether they’re eating gammarus, miss, small shrimp etc., only very few trout will refuse a well presented Red Tag size 12 or 14. I like the imitation game, but that’s a (slightly) different discussion.

Water clarity is an important factor to take into consideration when choosing a fly. It’ obvious to most, but the general rule of thumb of course is the clearer the water, the smaller the fly. In dirty, murky water I very rarely go for orange and other bright colours. Black is a heavy contrast and very visible and once you get deeper than the sun/light reaches, brightly coloured flies go grey.

When it comes to salmon, it’s common knowledge that late season salmon are usually best caught on small flies. But what’s a small salmon fly? Again water clarity is to be considered, but when fishing running water, another factor comes into play: Speed of current.

Most seasoned salmon anglers are of the opinion that the later the salmon sees the fly, the better the chance of a reaction. That is - if the salmon sees the fly swinging towards it 6 yards away, it’s less like to strike than if it sees it when it’s two feet in front of its nose.

I believe that the faster a fly moves, the smaller the salmon might perceive it. A long, slim fly (as in a lightly dressed Sunray Shadow) can easily be perceived as smaller than a heavily dressed #2 single hook, even though it’s 2 inches longer.

I also always try to fish my flies fast. In most conditions I find a faster fly more effective for salmon than a slower one. In slow water (as in Denmark) I usually add a retrieve of some sort to the swing. Maybe a figure-of-eight is enough to make the difference. Maybe a faster, standard retrieve will do the trick. Never do the same thing once, as Paul says. Danish salmon streams can’t be said to be fast, so I usually fish quite small flies. In later years rarely bigger then 5-6cm, even in high spring water.

Predatory fish have excellent vision, and I rarely go for a “big” fly as my first choice. If I see specific prey, I go for an imitation. If I’m “restricted” to choose fly based on experience, I usually go for the smallest fly I think the fish will spot (pike might be an exception).

Have a great weekend!

PoD: From Gaula in Norway. I didn’t land the salmon, but it was big, over 8kg. First of all the spot needed left-hand speycasting, which was why it hadn’t been fished much, and I know the spot - it tends to hold salmon. There’s a good, even current, where a cast across and a down stream mend gives the fly good speed. I had on a small Sunray Shadow, maybe 5cm long and after two swings over the spot, the salmon was on. It ended up bending out the hook.