I will not mention his name but suffice it to say that he is a well-known fly fisher whose fly fishing exploits have been chronicled in print for many years. We shared a day on a famous trout stream and enjoyed several hours of candid conversation about fly fishing. We covered a gamut of topics from rods to fly theory. Here are some of the interesting insights that I gleaned from that day.
We were sitting on the bank taking a break and the topic of selectivity came up. He picked up his rod and after making several casts he hooked and landed a nice brown trout. He landed it quickly, scooped it up in his net and came over and sat back down on the bank. He held the fish in the water still in the net and quickly removed the hook. Holding the fish in the water while it recovered he said, "Nice fish yes?" I nodded in agreement. The fish recovered and with a flick of its tail it darted back out into the stream. He rinsed his hands in the water and settled back on the bank.
"You just witnessed a creature that has no idea what just happened. He has a brain the size of a pea and within a short period of time it's possible that I could catch that same fish again on the same fly. Why, because that fish doesn't think, at least not in the same way that we think. His life consists of urges controlled by hormones. He eats things that look and act like things that look like they are edible and that may include some things that prove to be inedible. If the fly that I just caught him on comes over his feeding station again when he is engaged in feeding and it looks like food he will likely attempt to eat it again."
"So what appears to be selectivity to us involves something entirely different?" I asked. He nodded and told the following story.
"When we encounter a fish or maybe several fish that seem to be feeding selectively that is exactly what they are doing but not for reasons that we often attribute to that activity. We simply have misread what they are doing. One day many years ago I encountered several respectable trout feeding along the bank. There was a sporadic hatch of small olive mayflies and I thought that those fish would be easy to catch, but after over an hour of casting every fly in my box that was close to imitating the bugs on the water I had not hooked or even moved a single fish. I sat down on the bank and spent several minutes watching those fish and then I noticed something that I had not observed previously. I quickly dressed my fly, greased up my leader so it would float and made a cast just above the closest trout. As the fly approached his position I twitched the fly slightly and he rose confidently and sipped it in. Those trout that had thumbed their fins at me for the last hour became almost too easy when I twitched my fly when it floated over them. If the fly was fished dead drift they ignored it, they were only eating those flies that moved."
"Then selectivity does not mean that the fish can identify one bug from another?" I asked.
"Identify? Like the difference between a mayfly and a caddis fly? Yes and no. The fish would be able to see that a caddis fly looks different on the surface film and, I think more importantly, it acts different. So, if a large juicy mayfly floats over a fish that is eating caddisflies, even though the mayfly may be larger the first may reject the mayfly and eat the caddis. Is it being selective? Yes, but once again not for the reasons that we normally believe. It has nothing to do with recognizing one insect over another and everything to do with size, shape and behavior."
"In addition, there are occasions that are much more common than we think, when fish are feeding on a variety of types of food. If you have ever used a stomach pump to extract the contents of a fishes gullet and stomach you might be amazed to discover that the fish you just caught that took your dry fly is chocked full of nymphs, emergers and adult insects. It would be nice if they were arranged in hatching order: nymphs, emergers and adults but they are all mixed up. Was this fish being selective? Yes, but once again not in the way that we think of selectivity. The only way to sort out this type of feeding behavior is by careful observation and knowledge about what you are observing"
"Many anglers that I know feel that when a fish is refusing their fly that they should use a finer leader since the fish may be rejecting their fly because they detect the leader. What do you think about that," I asked.
"Do the fish see the leader is a rather illogical question. Of course they see the leader; they see all kinds of things floating in the water; strands of weed, sticks, and a plethora of other objects including things that they eat. The question is not if they see the leader but what does it mean to them and does the leader cause the attached fly to act in a manner that they are not observing in the naturals that they are eating. If fish could think logically and connect the leader to the angler then we would never catch any fish while fly fishing or by any other method."
"Think about this," he added. "You are fishing and a certain fish is continually rejecting your offering. You believe that it is because of the size of your leader tippet so you decrease the size of your leader by two sizes, let's say from 5x to 7x. That is a reduction in diameter from .006 to .004, a difference of two thousands of an inch. If a fish can detect a difference that small without a micrometer, and if that makes any difference as to whether or not they take your fly they are much too smart to ever be caught. In reality the diameter of your leader, whether it is floating or sinking, whether it is monofilament or fluorocarbon, and whether the fish sees it or not has absolutely nothing to do with whether or not the fish eats or rejects your offering. If your tippet affects the way your fly behaves and it causes your fly to behave different than the naturals it will likely cause the fish to reject your fly. However, the size of the tippet and whether or not the fish can see it is immaterial to whether or not your fly is rejected."
"But I know lots of anglers will change their tippet or use different tippet material and swear that it made a difference. What about those claims?" I asked.
"Well here is an interesting story. I was fishing with _______ [another well-known angler] one day on a stream that was known for its large and selective fish. The water was clear as fine crystal and the hatching insects were all size 18 or smaller. I would watch him fish and after he caught a fish then he would sit on the bank and watch me fish until I caught a fish, and thus we fished our way along until we stopped for lunch. When we were relaxing after lunch we started talking about what flies we used and I casually asked him what size tippet he was using. To my surprise he said he did not have a clue but he thought it might be 3 or 4x. I had a micrometer in my gear and when we measured his tippet it was a solid .008 or 3x. I had been using a .006 or 5x tippet and we had both consistently caught fish all morning. He said he rarely worried about the size of his tippet but he was far more concerned about presentation than tippet size. He might use a smaller tippet if the tippet he was using would not go through the eye of the fly!"
"I also had another interesting situation dealing with tippet material. I have a friend that I fish with once or twice each season. He comes to visit me from out of state and the only time that he does any fly fishing is when he comes here. As anglers go I would consider him your average angler; capable but not inordinately skillful. When the fish are easy he can hold his own but when things get technical he's lost. Anyway, he came to visit a couple years ago and he told me that he had heard about a new tippet material called fluorocarbon. I told him that I had some and he asked if he could try it since he thought that it would make a difference in his success. So, the next day I produced a spool of tippet material, snipped off his old tippet and tied on a length of the material from the spool. We started out fishing some nymphs and immediately he began to get into the fish. With each fish he caught his confidence continued to rise and by the end of the day he was literally walking on water. He was convinced that the "new leader material" had made a difference and he was going to switch over immediately. What I did not tell him was that the leader material he was using was not fluorocarbon but the fact that he thought it was made him more confident, he fished better, more focused and thus his success rate increased."
"These conclusions," he said "have created some heated arguments among anglers over the years, but if you look at the terminal tackle; the flies and leaders that were used say 75 years ago and compare them to what we use today, we would have to conclude that those anglers could never have caught any fish with a the equipment they were using, but nothing could be farther from the truth. Some might argue that the fish are more intelligent today because of the greater fishing pressure that they experience but again if that were true on our heavily fished waters it would be impossible to sustain the current catch rates. The fish in those waters would be far too intelligent to be fooled by even our more advanced leaders and flies. Fish do not reason like we do, they are not passing on knowledge to the next generation, they have no written history, no cumulative recollection of past events; they are fish not humans."
"Why do you think many anglers give capabilities to fish when they really are incapable of possessing them?"
"As humans we don't like to fail and we don't like to believe that we just can't always figure out every situation. If we assign intelligence to a fish then we have an excuse for why we were not able to make it take our offering. After we have spent an hour casting over a certain fish without any results we can make ourselves feel good if we can say that the fish was just to fly savvy for us to catch it. If we come back tomorrow and catch that same fish we can pat ourselves on the back and say that today we outsmarted that fish."
"I think the idea of giving fish logical abilities can best be summed up by a good friend of mine. This guy is an intellectual giant. He has enough advanced degrees in math and science to wallpaper his house. One day after we had finished fishing we were talking about the intelligence of fish and why it is that we attribute abilities to them that they do not possess. He looked me straight in the eye and said; 'If I can attribute some degree of intelligence to a fish then I can justify the fact that I was unable to catch it. If you think about it, it's really not much of an accomplishment to outsmart a creature with a brain the size of a pea!"