Game Fishing: What We Think a Fish Sees
Before we can even begin to studyobjectively we should ask ourselves what it is that the fish sees. This subject is fraught with difficulty. A fish has the brain of a fish, not of a man, and the images presented by its eyes are interpreted in ways that are obscure. Game fish are known to see certain shades of colour in certain conditions, but which colours and in which conditions is still a matter for speculation by the ordinary angler. Scientists have given us no cut-and-dried statements on this point. Furthermore, in spite of all that has been written about the fish’s window, some experienced observers feel that there is room for doubt, in that trout, for example, do not always react the way fish-window diagrams say they should. It is probably wise to work on the assumption that fish see a good deal more than we imagine.
It is untenable that themust be matched exactly with the natural in order to obtain good results. Experience is against this belief and so is common sense. If such a criterion were in force, we should never catch fish, simply because the exact imitation of a natural fly is quite beyond man’s ingenuity. Even the most skilled of professional fly-dressers admit that their work is crude when compared with the living insect. Simply to imitate colour is difficult enough. Few anglers possess the equipment or technical knowledge needed for pinpointing the exact tint transmitted by a certain fly in certain conditions of light. Translating this tint — when known — into the raw material of the fly-dresser calls for a skill far above average. We can only hope to approximate.
Fish see flies flying above or resting on the water-film. They will leap at airborne flies. Flies resting on the surface expose their undersides to the fish. This suggests that elaborate winging on the upper side of the fly is largely wasted effort.
Wet flies come in for quite a different form of scrutiny. Fish look at them from below, from the side, or even from above. Wet flies depend on size, approximate colour, and action for their success. Dry flies rely on size and colour only.
With, then, the best we can manage is a compromise based on size, colour, texture, form, and action. The last of these will be discussed later. Fortunately for fishing, our approximations work quite well in practice. When they fail, it is not necessarily the angler’s fault but rather because the has touched one of the many physical limitations intrinsic in its nature.