It’s something unstoppable, we’ve always been drawn to it. Closing our eyes and imagining that moment: that fish that leisurely rises to kiss the sky and leaves behind a ring, which gets etched into your retina and exerts such power over you that, every time the river fills with those magical rings, you lose your head, your sense of time, and can only think about them.
I’m sure this short story sounds familiar to many of you, and you’ve experienced it many times in your own flesh, but I believe it’s undeniable that in our rivers, those scenes are less frequent. No angler misses the fact that surface fishing is becoming less common, not because we don’t want it, but because it’s getting harder to see those “magical rings” disturbing the surface of our rivers. Year after year, the scene becomes less common; it’s harder to find moments when the fish feed on the surface, and those moments are usually shorter in duration. Why?
This country, in its short tradition as a “fly fishing” nation, has been predominantly a dry fly fishing country, so much so that many who have been in this for more than a quarter of a century spent many, many years using almost exclusively this attractive technique. It’s been in the last 10 years, maybe a few more, when subsurface fly fishing has experienced a tremendous boom, and I sincerely believe that, in many cases, the reason that has driven anglers to resort to these techniques has been, aside from the desire to catch more fish, the lack of activity from them on the surface. What do we do when our friends don’t show their faces? Do we wait? Do we fish blind… or do we seek them where they are? For this reason, it’s still not uncommon to find anglers who only start nymphing when they have no other choice, and there are many, many who got started this way and later, often drawn by its effectiveness, ended up embracing it. Unfortunately for the former, they have to resort to this technique more and more frequently; so much so that many have already gotten used to it and have great command of it, and even enjoy the heck out of soaking their nymphs in riffles and currents. Let’s not kid ourselves; I think most of us started in this because of the aesthetics and the artistry of that moment when the fish takes our fly on the surface, and I believe many, if we could, wouldn’t fish any other way. After all, for me, fly fishing was the ultimate expression of the “how,” versus the “how many” and the “any way possible,” and I’m sure I’m not the only one who thinks this way and still considers those magical moments of dry fly fishing as the true essence of fly fishing. But why is it becoming harder to dedicate an entire day to fishing upstream and finding fish on the surface?
To start, I think we can’t ignore that there are fewer fish, many fewer fish, as much as it pains us. This is indisputable, and it’s logical that if there’s 20% of the fish there were 30 years ago, there are also 80% fewer fish feeding on the surface, unfortunately.
Hold on. We haven’t considered an obvious question, and maybe we should start there: What makes a fish rise to feed? I don’t know if you’ve ever wondered this, but the answer isn’t as simple as “to eat.” Well, yes it is, but with many nuances. After all, every animal (including us) has a processor inside that does something as simple as a balance between effort and reward. In this case, we’re dealing with an energy balance, and it’s obvious that the cost of staying near the surface or making trips up and down for every fly involves an expenditure that must be offset by the caloric intake provided by the captured prey. All this without considering that exposure to predators is much greater. So, for a fish to choose to “go up,” it has to be worth it, and well worth it.
And why this question now? Simple: all of us who’ve been on these godforsaken rivers for a few years have noticed something: What happened to the hatches? I think if the deterioration of our trout populations is alarming, no less scandalous is the decline in the populations of macroinvertebrates in our waters. In most of our rivers, we enjoy fewer hatches in quantity, poorer in number of species, and briefer in time. And without subimagos, emergers, or other types of “flies” floating on the water, there are no rises; our friends won’t position themselves eye to eye just below the water’s surface, and consequently, we won’t be able to enjoy this spectacle. In short, it’s getting harder to balance that darn equation.
The potential causes that may be leading to this decline in macroinvertebrate populations in our riverbeds are numerous, but I believe the main one is pollution, as many of the species that trout feed on are very sensitive to it. In fact, many of our favorite flies are often used as bioindicators of environmental quality.
Another potential cause, and here we run headlong into one of the big problems of our rivers, which has a double effect on the issue at hand, is none other than dams. Yes, those damn reservoirs and their releases again. Broadly speaking, any structure that cuts the “river continuum” (River Continuum Concept) is something to study down to the millimeter, and its consequences are usually hard to predict. If we add that the use made of them doesn’t correspond at all to what we’d call sustainable use, we have an ecological problem of considerable proportions on our hands. One that’s very little considered, by the way.
The first consequence that directly affects the matter at hand is the silting of bottoms that become saturated with mud, silt, and sand from the reservoir bottoms. The stony beds of many of our rivers, to which the inhabiting species are adapted, become less welcoming as a result of this, and populations of certain species are displaced, reduced, or even disappear. By the way, it’s obvious that this silting also very negatively affects the survival of spawn by exponentially decreasing the quality of spawning grounds.
The second important factor is water temperature. You’ve all noticed what it is in our regulated rivers year-round: cold, cold… but really cold. This factor in particular doesn’t have to overly affect macroinvertebrates, but we have to consider that they’ve been evolving for thousands of years in an environment with a temperature a few degrees higher than the one we’ve suddenly imposed on them in 40 years. For some species, an average annual decrease of 1°C can be enough for their populations to dwindle progressively.
However, it’s not their influence on the flies that I think affects us the most, but the influence on the metabolism of our trout. As you know, trout are ectothermic fish, commonly known as “cold-blooded,” which regulate (or rather don’t regulate) their body temperature through the environmental temperature, in this case directly depending on the water temperature for their metabolic rate and level of activity. For brown trout, the temperature range in which their activity is maximum oscillates between 12°C and 18°C (there are variations depending on the literature, but it serves to understand). Anything below this optimal temperature range for trout will slow down their metabolism, their ability to be active, and as a consequence of that metabolic reduction, their need to feed and eat. It doesn’t mean they don’t eat, but they eat less and also try to do it more efficiently, and let’s not kid ourselves, rising to the surface is usually a pretty inefficient way. It’s much more economical, energy-wise, to stay on the bottom sheltered from the current and let it bring us nymphs and other food.
Yeah… and those incredible videos from abroad where the fish feed on the surface like crazy and the air and water temperature is at least cool? Well, we have to understand that where we now have an Esla, say, 40 meters wide, with a flow of 20 m³ and water at 10°C, for thousands of years (or better, summers), there was a dry wasteland with a river that heated up above 20°C. We’re in the southernmost country in Europe, and our trout populations have evolved and adapted over millennia to our climatic conditions, and it’s reasonable to assume they’re more adapted to overcoming harsh droughts and being more active at favorable temperatures than to enduring permanent winters and temperatures below 10°C with brutal flows in the middle of August. Draw your own conclusions.
The overcrowding of our rivers is a fact today. It’s increasingly difficult to enjoy a day without crossing paths with another fellow angler or just staking out a pool in solitude. To the point that in some spots, fishing stops being a bucolic and peaceful activity and becomes just another way to socialize. Gone are the days when in this country there were 1 million cars and trips 200 km away were a real adventure on back roads and took several hours. We’re in the era of communication, and this doesn’t just apply to the internet. Nowadays, anyone has a car in their garage and can get to any river in this country in a few hours. There are more and more anglers, for better or worse, though I think so far we haven’t gotten any benefit from it and plenty of misfortunes.
If sometimes the starts of the season or fishing a well-known stretch can be more stressful than the office desk, or at least to me sharing a stretch with another 15 anglers seems that way, imagine the situation for its inhabitants. In my case, that’s why I eagerly seek out less frequented stretches or methods that, though less prolific in catches or more demanding in effort (let’s not kid ourselves, but people still struggle to walk an hour to fish a stretch, thank god), allow me to enjoy the river and nature in peace. But that’s another story.
Back to the point: it also affects our trout a lot. Not just because there are more anglers who want to get their spines in the frying pan, but because this influx of people ends up modifying their habits and behaviors, and that’s where we hit the issue at hand: to what extent does fishing pressure affect the surface activity of our trout? It’s clear that our presence in the river alters it in many ways that we sometimes can’t even imagine; perhaps the most evident is the general deterioration of them, but the change in habits of our friends is something we can’t ignore. It’s obvious to anyone that for a fish, feeding on the surface is probably the period when it’s most exposed, and therefore, it’s a time when trout need certain tranquility and calm to feel safe while feeding. Any presence or element foreign to the environment can alter this behavior, and if that invasion of their privacy is repeated and also associated with danger, like getting hooked with the consequent toothache (that’s in the best case, being able to tell the tale is already an achievement), it can lead to a change in the habits of our friends. This is fishing and they are trout, so “where I said I say, I say Diego,” and we might find the opposite, fish feeding that ignore everything, but generally, it tends to happen that in heavily fished stretches or already late in the season, it’s harder for them to gift us those moments, unfortunately. As an anecdote, note that those of us lucky enough to enjoy walks by the river out of season usually find peaks of surface activity that we’d wish for with a rod in hand… the curious thing is that often the theoretical conditions are much less conducive to it, but simply the fish are calm.
Along these lines, I’ve always asked myself the question I pose next: Does human fishing activity over recent history have a selective effect on the genetics (understanding that this encodes certain aspects of behavior) of trout populations? Let me explain: research is being done on how pressure exerted over generations on salmon populations that enter during open season has reduced them, logically, but however, the populations that entered after the season closed are in much healthier shape. In short, we’ve eliminated the genetic stock from March, April, May… and the later one that hasn’t suffered pressure from us has perpetuated. Extrapolating this possibility, I can’t help but wonder if the pressure exerted over decades on these populations with a penchant for feeding on the surface has affected our current populations.
In short, we could conclude that for our trout populations, it’s becoming harder to make the numbers add up so that the caloric balance and risks of feeding on the surface pay off; that the ideal conditions of temperature and flow occur less frequently; and that the much-needed tranquility is an increasingly scarce commodity. However, I can’t stop scrutinizing every pool, every run, in search of those rings that remind me why I started in this, in search of the essence of fly fishing.
*ARTICLE PUBLISHED IN DÁNICA MAGAZINE NO.54