It is very much my contention that trout , and trout in catch and release waters in particular, will “learn” to avoid getting caught if they can. That is not to suggest that they necessarily go through any complex cogitative process but simply that, like all wild creatures they adapt to their environment to reduce wasted energy and tend not to do what is biologically inefficient.
On waters where there are strong insect hatches the obvious answer is to only eat specific insects at specific times which has in angling circles resulted in a near blind faith in “matching the hatch’. Something that I am quite sure has its place and an approach that even on the less fertile streams becomes critical at some times where the fish have honed in on beetles or ants or some such to the degree that anything less than a close copy is ineffective.
However much of the time on the less alkaline streams the fish really need to make the best of a bad job and eat whatever becomes available, a sort of mixed grill of bits and bobs that float down the river, from the wayward beetle to the odd caddis and over selectivity under such circumstances would see the fish burning more energy than they were taking in. Nature tends to be pragmatic and if there is food there the fish are more than likely to make the most of it. A situation which I would hypothesize makes the trout more vulnerable to being caught because the old selectivity saw doesn’t offer any protection from making a mistake and ending up with a hook in the lip and together with that a large waste of energy struggling to escape.
To my way of thinking, and of course I am not a trout and don’t really know what trout think, it would seem that the “behavior” of the fly makes for a pretty reliable means of selecting the good from the bad or the real from the doppelganger. Most certainly the more heavily fished a water becomes the more sensitive fish become to inappropriate presentation and when fishing dry fly “inappropriate presentation” means drag.
I well remember my first introduction to drag in a library book on fly fishing back in the day when such didn’t include photographs at all and descriptions were merely embellished with line drawings. So the line drawing of a fly “dragging” showed a dry fly whizzing across the surface at sufficient pace to leave a wake behind it like the spume from the back of a ski-boat.
Certainly that is drag but it is the most severe version and there are many more subtle variations, some frequently referred to as “micro-drag” which are virtually imperceptible to the human eye. Anything from that obvious wake to the fly travelling at slightly less or more than the speed of the bubble next to it can be sufficient to warn a trout off making a mistake. So the question arises, and it is an enquiry that has been asked of me more than once, “how much drag is too much” and the simple answer is any.
However lets put the idea of drag into a metaphorical frame so that perhaps novice anglers will get the idea as part of a clearer picture. It is a description that I have used frequently in various fly fishing classes and it seems to get the message across.
The power of repetition.
Trout tend to live in specific spots on the stream and if the angler puts himself into the fish’s fins as it were he will recognize that the fish becomes extremely used to the way things happen on his particular little bit of water. Sitting comfortably in his favourite feeding lie the trout will see thousands if not millions of bits and pieces get carried along in the current. Each one, be it leaf litter, a bubble, an insect or a piece of weed will be driven by the current in exactly the same way over and over and over. Come down the current lane, flip to the left past the large boulder, spin slightly in the eddy and then get whisked away over the fish’s head. Over and over and over again. One has to concur that this would lead to an extreme and probably near sub-conscious familiarity with the way things are. With such a repetitive process occurring all the time any variation is likely to show up quite clearly.
Drag and your steak dinner.
So let’s put you in the trout’s position, imagine that every Friday evening you go to your favourite restaurant and order fillet steak. The same waiter every Friday puts you at the same table, you look out the same window, eat off the same table cloth and greatly enjoy the same portion of nicely done fillet with the same knife and fork , the same lighting, same same same, Friday after Friday after Friday.
Then on one particular visit the same waiter gives you the same greeting, takes the same order for the same steak dinner and when it arrives you pick up the same knife and the same fork, already in Pavlovian response anticipating the taste of your succulent first bite. So the question is this “how much to you think that that steak would have to move on your plate to get you to lose your appetite”? That is drag and I think that you would agree, put in those terms you wouldn’t really even have to measure the degree of movement to know that something wasn’t quite right. A slight sigh on the part of your fillet would no doubt be enough to put you in panic mode.
So next time you are assessing “how much drag is too much” I suggest that you think of that fictional steak dinner and it should put things into perspective.