If you want to have more success fly fishing lakes, you need a good understanding of how lakes work—knowing how lakes work helps you get to the right spot at the right time, no matter the season.
You’ve probably heard the saying that 90% of the fish live in 10% of the water, and it’s true for lakes just like rivers and streams!
In this two-part series on how lakes work, Phil Rowley and Brian Chan break down everything you need to know about fishing lakes effectively.
Brian has spent over 30 years as a fisheries biologist for the provincial government, specializing in managing trout lakes in the interior regions of British Columbia. Over the years, he worked on hundreds of lakes, managing them, stocking them, setting regulations, and carrying out habitat protection and enhancement work.
Brian is also an ambassador for several fly fishing and boating companies, including Scientific Anglers, Sage Fly Rods, Islander Reels, Marlin Boats, Semperfli Fly Tying Materials, and Daiichi Hooks.
He is a passionate fly fisher and fly designer, and together with Phil, they’ve put their expertise to good use through their online fly shop.
Lakes aren’t all the same, and knowing how they work is key to becoming a better stillwater angler. Here’s what you’ll learn in this episode:
pH is a scale that measures how acidic or alkaline a lake is, with 1 being super acidic and 14 being super alkaline. The pH level affects the water chemistry, impacting how well the lake supports aquatic life, from insects to fish.
The best pH for trout lakes is between 8 and 9.2. This is the sweet spot for plant growth and lots of invertebrates, which are food for trout. If the pH exceeds 9.2, the water becomes too salty for trout, and it would not be easy for them to survive.
For example, lakes like Pyramid Lake have a pH above 9, which is perfect for Lahontan cutthroat trout but challenging for rainbow trout. The pH scale is logarithmic, meaning small changes in pH can make a big difference in fish survival.
Brian explains that pH levels in lakes aren’t always the same and can change over time due to several factors:
Lakes can be divided into three categories: oligotrophic, mesotrophic, and eutrophic. These classifications help us understand which lakes are better for fishing and support healthy fish populations.
Knowing the type of lake helps anglers figure out why one lake might be an excellent spot for big trout, and another might not be as productive.
Oligotrophic lakes are big, deep, and well-oxygenated, with lots of water flowing in and out. The flushing rate in these lakes is high, meaning the water changes quickly, so there isn’t much shallow water for plants to grow.
Because of this, these lakes have limited food sources for trout. Fish here mostly survive by eating other fish, not just insects.
Mesotrophic lakes are a step up from oligotrophic lakes in terms of productivity. They’re still large but a bit shallower, and they often have small rivers or creeks flowing in and out. The lake has a bit more shoal areas or littoral zones, so some plant life grows in those shallow water areas.
Eutrophic lakes are the gold standard when it comes to trout fishing. They’re shallow, nutrient-rich, and full of life. These lakes are often less than 50-60 feet deep and have lots of shallow areas for plants to grow.
These lakes’ flushing rate is slow, so they stay nutrient-rich for longer. Chironomid fishing is also incredible here due to the muddy bottoms.
Lakes have different zones, and understanding them helps anglers know where to fish at various times of the year.
The littoral zone, or shoal area, is the shallow water at the lake’s edge. This is where sunlight can penetrate to the bottom to create photosynthesis. It’s usually 7 to 8 meters deep.
The littoral zone is where all the vegetation grows and where trout and other fish species feed, particularly in the spring to early summer and again in the fall, right until freeze-up.
This is the zone where we spend the bulk of our fishing time—whether it’s 5 feet of water or 22, 23 feet of water—this is the prime area.
The limnetic zone is the open water area in the middle of the lake, just beyond the littoral zone. Here, sunlight still penetrates, but it doesn’t reach the bottom. This means there’s no vegetation growing like in the shallows, but it’s still a prime habitat for zooplankton, which trout love to eat.
Although this zone has less food diversity, the zooplankton and deep-water hatches make it an essential spot for fish. In the warmer months, fish move out of the shallow water and into the limnetic zone, where the oxygen levels are better and the water is cooler. This is when fishing techniques like using blob patterns can be incredibly effective.
The thermocline is a transition layer between the warm upper water and cooler deeper water. It’s usually a narrow band, about a meter in depth, where there’s a sudden drop in temperature.
The thermocline keeps the colder water from mixing with the warmer water, which is why the deeper parts of the lake stay cool and oxygenated. Fish often move from the shallow waters to sit just above the thermocline, where they find cooler water and better oxygen levels, especially during hot summer months.
Remember, all lakes are different, but understanding lake structure makes your fishing day more successful and enjoyable!
Episode Transcript
1 (2s):
Welcome to the Littoral Zone podcast. I’m your host, Phil Rowley. The Littoral zones, or Shoal area of the lake is a place where the majority of the action takes place. My podcast is intended to do the same, put you where the action is to help you improve your Stillwater fly fishing on each broadcast. I, along with guests from all over the world, will be providing you with information, tips, and tricks, flies, presentation techniques, along with different lakes or regions to explore. I hope you enjoy today’s podcast. Please feel free to email me with your still water related fly fishing questions and comments. 1 (42s):
I do my best to answer as many as we can prior to each episode just before the main content. Thanks for listening. I hope you enjoy today’s show. Although I’m not a biologist by profession, I’ve always been fascinated by nature and trying to understand how and why things work. This skill has proven especially valuable to me when fly fishing lakes. If you want to be successful fly fishing lakes, one of the critical skills you need is a good understanding of just how lakes work. Understanding how lakes work helps put you in the right place at the right time throughout the season. The adage that 90% of the fish live in 10% of the water is just as valid on lakes as it is on rivers and streams. 1 (1m 29s):
Joining me for my two part series on how Lakes work is good. Friend, mentor, business partner, fly Fisher, brand ambassador, author, and fisheries biologist, Brian Chan. In today’s podcast, part one, Brian and I will be discussing how lakes are classified and the different zones within a lake, including those zones. We as fly fishers should focus the majority of our attention on part two of the series focuses on the seasons of a lake and their impact on fish location. Let’s get started. Welcome back. It’s good to have you again. For those of you who aren’t aware or haven’t listened to previous episodes or other episodes, I guess that’s the same. 1 (2m 13s):
Brian was my first live guest on episode two when we talked about Brian and I, obviously, obviously maybe you don’t know, but we’ve been good friends for many years, do lots of things together. We have our own online Stillwater fly fishing store that I guess Brian and I, we strongly encourage you to go visit. We’ve got all kinds of good stuff for Stillwaters there. But Brian, why don’t you, for those that maybe haven’t listened or don’t know anything about you, I can’t imagine out there in the Stillwater world that exists, but perhaps it does. Why don’t you tell us a little bit about yourself, background, how you got into fly fishing and you role in, in the fly fishing community? 2 (2m 51s):
Yeah, no, that’s great. I can do that, Phil. Yeah, and it’s great to be on online chatting with you again, and I’m sure there’ll be be lots of good information tonight. So for those that aren’t familiar with my background, I was very fortunate to be a, a fisheries biologist for the provincial government for over 30 years with my specialty being the management of Trout Lakes in the interior regions of British Columbia. So I was able to work on six, 700 lakes in a very large area over those years. Managing them, stocking them, setting regulations, doing the habitat protection work enhancement work, things like that. 2 (3m 34s):
So, and you know, I’m very familiar with the cycles that lakes go through each year. And being an avid Stillwater fly fisher, having that biological background about fish and lakes, entomology and ology, as well as fisher’s biology, it set me up for a perfect career as well as a passion. And like yourself, Phil, a fly designer, which you and I have put to good use through our e-store. I’m a, an ambassador for a number of companies in the fly fishing and boating industry, including scientific anglers, sage, fly rods, islander reels, marlin boats, semper fly fly time materials and daiichi hooks. 2 (4m 25s):
And also having professional relationships with other companies as well. And like you said earlier, we go back many, many years and it never gets old talking about fly fishing and particularly our passion of fly fishing still waters. So it’s great to be back on board with you. 1 (4m 46s):
Well, it’s great to be with you tonight, Brian, and, and tonight we are talking about something that you touched on the ology. This is the first of two episodes on how lakes work. It’s a big subject, that’s why we’re doing it in two episodes, to give it the discussion it needs. And today’s subject is about something I, I think we both firmly believe that all still water flies. Fisher should know, you know, lakes aren’t created equal. And we’re gonna talk today about lake types, how they’re broken down and zones of a lake, because it’s really critical information to know, isn’t it, Brian? 2 (5m 21s):
Yeah, it, it’s absolutely a sound background of how lakes change through the year as well as the different classification, the lakes. It’s the foundation of becoming a successful Stillwater fly fisher. No question. 1 (5m 39s):
Yeah. ’cause if you don’t know where to go or why lakes are different, why is a coastal lake or deep lake different than a, some of the lakes you get to spend your time on in the cam area, why are they not all the same? So, you know, I think for us it helps eliminate that non-productive water so we can consistently catch fish throughout the season. So tonight we’re gonna talk about that, we’re gonna talk about lake productivity and pH. We’re gonna talk about the three types of lakes, the sea classifications, and then we’ll walk you through the zones of the lake. And then part two of this podcast, which will be released at a later date, we’ll focus on the different seasons that lakes go through each year and how that impacts fish movement and behavior and things like that. 1 (6m 23s):
So Brian, why don’t we get into lake productivity and let’s maybe start talking about pH first and all that stuff you took in high school chemistry. Wonder if you would ever put it to use, guess what? 2 (6m 38s):
Yeah, you bet. So, yeah, you know, pH is a really good topic to start off with. So pH is a, it’s, it’s a relative scale of the, from one to 14 on the, the range of whether the lake is acidic to neutral, to alkaline. The pH of one is extremely acidic, whereas a pH of 14 is extremely alkaline. And depending on the lake type that we’re talking about, the pH will tell you so much about the relative productivity in terms of water chemistry, and as a result, how productive the lake will be in supporting invertebrate life, aquatic insects, and then eventually fish. 2 (7m 28s):
So on a scale of one to 14, with seven being neutral, we find the most productive trout lakes have phs of eight to about nine, 9.1, 9.2. That’s the sweet spot for productive trout lake in terms of the aquatic plant life growth, the diversity of invertebrate life in the lake, which are the food for the fish and for the survival of salmon, which are trout are are member of that family. So that sweet spot between, you know, even a little bit less than eight, but not above about 9.2 is where If you, If you looked at some of the most productive lakes that you fish, whether they’re in North America, Europe, or South America, they’re gonna be in that eight to 9.2 range. 2 (8m 26s):
And once you get above that, the pH one, 9.2, the lake, the water basically becomes too salty in terms of supporting trout. And they have a difficult time in with their osmo regulation in breathing and the transfer of oxygen. And so that’s why trout species such as lahan and cutthroat are naturally much more adaptive to high pH water. And so the lakes that you like to fish fill, like Pyramid Lake for LA hot and cutthroat, I would just looking at that water and, and the lay of the land, I’m sure the pH is over nine and those LA hunting and survive in that. 2 (9m 14s):
And, and I would suspect that rainbows would be challenged to survive in that type of water environment. 1 (9m 22s):
Yeah, I think actually historically Pyramid Lake was part of a larger sea back in prehistoric times through as time passed became landlocked, but still retained that because yeah, the pH on that I think is, as you said over nine. And it’s interesting ’cause I, you mentioned like 9.1, 9.2, and I think it’s important that people realize it’s not like a change in temperature, is it? Where it goes from, you know, 69 to 70 degrees, that’s only one degree. Right. But on the pH scale, it’s significant, isn’t it? 2 (9m 53s):
It’s, well, it’s logarithmic. So yeah. You know, going from pH of 8.2 to 8.3 is a significant change in pH and so it kind of builds up. And once you tip the scale and go over pH nine, then we’re, even the slightest change increase can have an effect on trout. On rainbow trout survival, that’s for sure. 1 (10m 19s):
Yeah. And it can change too. The, the pH isn’t fixed. I think in discussions we’ve had outside of this podcast, you talked about a neat term. You’ve used a couple of times cultural eutrofication. I love that how PHS of lakes can change both by water levels and by, you know, human development around a lake or within enough of the water table of a lake to impact pH two. Isn’t that correct? 2 (10m 45s):
Absolutely. You know, each lake is like, its individual ecosystem and you know, most lakes rely on some form of spring flushing. So snow melt coming down and flushing through the lake to recharge some of the nutrients in the lake and maintain a balance in the, in the water chemistry. So things that impact the overall water chemistry of the lake. And certainly the pH can be the amount of timber harvesting that has occurred if it’s in a forested area, because that changes flow regimes and the water quality of the water coming into the lake, how much water comes into the lake and for how long you get spring shut. 2 (11m 33s):
Climate change is having a significant impact on our lakes in many parts of North America. And I’m sure in other parts of the world as well, because we no longer, and where I live, there are snow packs, which us we would get, you know, up to a meter and a half of snow typically around our lake. And we’re not seeing that on a consistent yearly basis anymore. In some years we have hardly any runoff. And so those lakes aren’t getting that recharge of good water coming in there. And so when lakes don’t fill in the spring and you get, you know, a good amount of natural evaporation because we we’re in a a dry climate, the pH is gonna go up. 2 (12m 16s):
And as we already mentioned, you know, just going up a 10th of a point of pH it can be a significant change in the overall water chemistry that not only affects survival of fish, but also it affects insect life and how they survive. Because changes in pH also changes the diversity of plant life in lakes. And they can, we see die offs of long stem bull rush and cattails due to fluctuating water levels as well as changes in the pH of the water. And we see the proliferation of other species of plants that were very, very minor in abundance in previous years and now have taken over lakes because of the changing water chemistry. 2 (13m 5s):
So every year’s different on the lakes, but I think it’s safe to say that there a lot of lakes, certainly in the western hemisphere are undergoing radical changes due to changes in climate. 1 (13m 17s):
Yeah. Well you mentioned that, you know, some of our listers probably aware of some of the lakes you fish and I fish as well. Roche comes to mind just located south of where you live in Camloops. And years ago that lake used to be pretty clear, Marl and cara, which is marl, is precipitated calcium looks like sand on the bottom and you don’t wanna stand on it ’cause it doesn’t behave like sand. But that lake is totally different today, isn’t it? 2 (13m 42s):
Absolutely. It’s no longer a, a crystal clear lake that never had algal blooms. Now it has major blue-green algal blooms in the summertime and the water has a slight tannic stain to it. The plant life com the species composition is changing and the moral shoals that we used to see are now in filling with vegetation. So we don’t have those nice clear moral patches where the fish used to cruise over and, and pick off shrimp in, in the fall months. It’s a different environment for them. And two years ago, the first time ever, we had a complete winter kill on that lake and it’s never ever happened. 2 (14m 27s):
And certainly in the 40 plus years that I’ve known it, and even historically we might’ve had just the odd partial kill, but it was, we, we suffered a total kill that was all due to changes in water chemistry, changes in water levels, and then changes in local weather patterns where a fall turnover never occurred that year, not fall. And that, that just spelled disaster for many lakes. And that’s a topic we’ll get into in a future podcast. 1 (14m 58s):
Yeah. And, and I also remember stump again, just a little bit further down the road, had real low water issues and that changed the pH the rainbow and the Koch inhabited that lake really struggled. And at one time I think you guys were looking at stocking alternate species in there to deal with that new pH environment. But thankfully the lakes came back up and things changed and sort of went back to more normal. If there’s such a state nowadays, 2 (15m 21s):
Yeah, it, it’s, we need that water, we need that spring fresh at to sweeten the water in our lakes to have a little bit leave in the spring and some new water come in. But that amount of water or how much water comes in each spring is really unpredictable. Now it just says simply ’cause of our snow pack, you know, our precipitation amounts that we’re getting total precipitation is, is changing. Every year is different. 3 (15m 50s):
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And it’s the same here in my local lakes and where I travel around, I’m sure it’s the same for you. It looks like the tide’s out sometimes on the lake, so water levels drop, your boat ramp is no longer accessible. All these, you know, all clues that, you know, things aren’t good. But this all falls into, you know, why do you need to know pH because it helps classify lakes, right? Like there’s different, there’s three basic classifications of lakes. Maybe Brian, you could walk us through those and why it’s important to know the difference because this helps determine one lake’s a better fishing opportunity or a better environment to grow, you know, production and, and grow big fish. 2 (17m 23s):
Yep, sure. So we have three classifications of lakes. When you look at ’em limb logically, we have oligo trophic, lake meso, trophic lakes, and u trophic lake that u trophic lake are, are the ones that we focus on for producing the best tr fisheries. But it’s important to understand what the characteristics are of each of these three leg types so that when you look at them, you can say to yourself, oh no, that makes sense now of why that lake isn’t a very good tr fishery. So oligo tropic lakes are the lowest in productivity. They’re well auctioned, they’re big, they can be like big oceans deep, they have big rivers coming into them, big rivers leaving them, and smaller streams and rivers coming into them as well. 2 (18m 16s):
They have limited amounts of shallow water or literal zone, which is a key component of productive trout lakes. And because there’s such a h these lakes have so much water coming in and going out because of the rivers coming in. And that, that’s called flushing rate. So the flushing rate of those lakes is, is the time to flush that lake is very low in terms of how many days it takes for the entire water column of one lake to volume to be completely replaced with new water. That time is months in some cases. So with all that water going through, you know, the and limited shallow water for vegetation to grow on, there’s not a lot of food in those lakes in terms of invertebrate food life. 2 (19m 6s):
So fish that live in those lakes and including trout and char, they survive by being ous, meaning they eat other fish, other non-game fish species or cokey or white fish, things like that. Or other fish species like suckers and shiners and minow minow species. So not your go-to trout lake that you think you can go out there and catch fish on chron it, granted there’ll be some CID there, but it will be very limited as to where they live and and to how abundant or diverse those populations are. And then we go from oligo trophic lakes to meso trophic lakes, which are a little bit more productive in terms of water chemistry than the larger oligo trophic lakes. 2 (19m 58s):
They’re still can be relatively large lakes, they’re a little bit shallower in depth. They still have potentially small rivers or large creek systems flowing in and out of them. But there is a bit more shoal area or or literal zone in the lake so that there’s some plant life that’s growing on those shallow water areas. And because the water chemistry is a little bit more productive because the water doesn’t flushing rate is longer, the water stays in the lake a little bit longer. So there’s a little bit more nutrients in the lake, stays in the lake. So you could have some interesting fishing at at River MAs, at creek MAs, things like that. 2 (20m 41s):
And you could potentially could have some ate hatches and, and certain may fly hatches and, and the deltas, the smaller rivers or or streams that are flowing in and out of the lake. And then we go from meso trophic lakes to u trophic lakes, which are our gold medal trout lakes, they have the highest levels of productivity. They’re relatively shallow, you know, maximum depths, often less than 50, 60 feet. And there’s always exceptions to the row, but there’s certainly not two and 300 feet in depth. They have abundant shoal or littoral zone where the sun can penetrate to the bottom and allow photos, photosynthesis to occur, which green plant life provides habitat for invertebrates, aquatic insects as well as trout. 2 (21m 33s):
They have typically only small streams, which are often ephemeral only flow in the spring and then dry up during the warmer summer months, or they’re totally landlocked. That’s the most productive ones. So that the only runoff coming into the lakes is from spring surface runoff coming into the lake. So they’re shallow, they have lots of shoal area and setting a flushing rate of those lakes is years. It takes years and years for the entire volume of the water of these lakes to be replaced with new water. So they’re like a, a standing compost box of water that’s nutrient rich, often associated with in climates where we have long growing hot summer periods. 2 (22m 20s):
So lots of sunlight, lots of photos, lots of essential nutrients, phosphorus, calcium, nitrogen to grow the plants, which provides the habitat for a lot of the aquatic invertebrates and insects like shrimp and dams and maze and dragons and chron that trout and other fish species focus on these lakes are prone to algal blooms. You get green algae blooms as well as blue-green algal blooms, which is just telling you they’re an extremely nutrient rich body of water and lots of phosphorous, lots of calcium, lots of nitrogen. 2 (23m 1s):
And the ideal situation is that there’s a perfect balance of those chemicals. So you may, you may have algal blooms, but you’re still gonna, the blooms are gonna die off light in the fall and they don’t come on until early to mid-summer months. So in the spring and late four months, the water’s clear again. But you’ve got muddy bottoms versus rocky or sandy bottom lakes that are common in oligo trophic and me atrophic lakes. In eutrophic lakes. You’ve got mud. When you’ve got mud, you’ve got cid. And that’s why we have our most productive chrono and fishing in atrophic lakes. 2 (23m 41s):
Massive diversity of species of insects, particularly CID and huge emergencies. So you can now drive by a bunch of lakes in the area that you live and look at them and go, well yeah, now I know why we don’t, you know, we don’t fish this lake and we’re going, we’re driving another hour to get to a, a shallow one. And that’s the reason why. Yeah, 1 (24m 3s):
Because you know, they look at some of those lakes, I’m thinking geographically, and maybe we can help our listeners separate them geographically, where we, we would tend to see your oli atrophic lakes. I remember them sort of on the west coast when I lived there that would, I would sort of limp through the winter and early spring because they didn’t ice over. The poor fish in there looked more like snakes than anything else. I think they were starving to death. They were deep. No shoals. What sort of pH range would we see in an oli atrophic lake? Seven, six and a half, seven 2 (24m 35s):
In oligo tr lakes. The pH is gonna be, you know, seven to seven and a half at the very highest I would think meso atrophic lakes are gonna be, you know, low sevens to high sevens. I don’t know of any meso atrophic lakes that are that touch pH of eight. And then you get into you really productive atrophic lakes. And then that’s when you’re talking, you know, seven and a half plus. And again the, the pH of your trophic lakes will change depending on whether they’re coastal lakes or inland lakes. And you know, obviously our best trout lakes are whether you’re, you’re in, you know, Manitoba, Saskatchewan, Alberta, bc, Washington, all the way down to California and in the east into the Midwestern states, their pH o lakes are gonna be, you know, eight and above and you’re gonna, except for the ones on the coast, and you’re gonna have all those such a diversity of aquatic life in them from plants to bugs to fish. 1 (25m 38s):
And as you mentioned, you can have little pockets where you’ll have a, a region that’s predominantly a li atrophic lakes. You’ll have that one little ru not really run to the litter, but that one exception, that’s a pure atrophic lake, isn’t it? It can be a little bit of anomaly like that. 2 (25m 54s):
Absolutely. There’s, you know, there’s always pockets of productive lakes, productive atrophic lakes sitting amongst large, you know, coastal type lakes. But once you basically cross the Rockies or the coast mountain range and get into the drier climates of the interior regions and then and beyond, once you cross the Rockies, then you’re into really a lot more atrophic lakes over there as well. So, you know, it, it follows the trend all the way down, you know, into the Midwestern states. Yeah, 1 (26m 28s):
It’s like a spine, isn’t it? The lakes, just like I say, over the coastal range, maybe the sandwich between the coastal range and the Rockies and then east of the Rockies. Those are just rich with atrophic type lakes. And of course you and I like to chase other things in lakes besides trout. And that’s where probably in the Canadian shield you’re seeing more of those me atrophic lakes with your lake trout, your pike walleye populations, lots of rocks, some weeds, lily pads, weeds like that. That fair to say? Yes. Okay, so this is important, right? Because it helps you choose, you know, like you said, you go to one lake and why, you know, you might get, I’m sure as a biologist you were getting emails, how come Lake X, you know, you stalk all these fish in there and how come they don’t get any bigger, you know, they’re put in there obviously for recreation purposes, but those fish are never gonna, you know, have a chance to get to the lakes you’re used to seeing and around your local waters, right? 2 (27m 17s):
Yeah. It’s every lake depending on it. The water chemistry will only grow so many big fish or lots of little ones. And so how you, how you stock it and numbers, you stock the strains of rainbows or other fish species you stock all determine in the end how big those fish are gonna get. As well as how they’re managed for catch rates or whether they’re catch release or they have a high catch rate. So as we mentioned earlier, every every lake is a unique ecosystem and, and they have to be managed individually. 1 (27m 54s):
Okay, so we’ve talked about the different classifications, li atrophy, meso, atrophic, atrophic within each lake there are different zones, aren’t there? And lakes are classified in there. And maybe we can walk through those and where they are and why they’re important and how where fish will relate to them at different times of the year, the season. And we can walk through all of those. 2 (28m 17s):
Yeah, so our, you know, our discussion is now basically gonna be focused on these atrophic lakes, on the tr lakes. But we break a lake down into several zones, starting from the edge of the lake, the shallow water as we go from the edge of the lake called the littoral zone or the shoal area of the lake. And that’s basically that area of the lake where the sunlight can penetrate to the bottom to create photosynthesis. So it’s usually seven to eight meters in depth. It’s about the maximum extent of sunlight energy. And so that’s basically what we call the, the shoal area of the lake. 2 (28m 59s):
And then once we get to the edge of the shoal, then we have a drop off, defined drop off that slopes down into deep water or the deep water zone of the lake. And so that in a nutshell, that’s the basic three parts of the lake. But we do have specific names or terms that we identify each parts of those lakes. The electoral zone is, is a very important zone of the lake because that shallow water is where all the vegetation is growing. That’s where the prime feeding of trout and other fish game fish species and other fish species feed, particularly in the spring to early summer. 2 (29m 41s):
And then again in the fall, right until freeze up. That’s the big grocery store. That’s where the shrimp are, that’s where the dams and dragons and leeches and chron and the majority of chron are coming off. So it’s also prime habitat for juvenile trout. But the big boys come in there as well to feed when the water’s the right temperature and there’s adequate oxygen, they’re gonna be in there. So that’s typically from ice off until early summer in most lakes. Sometimes they can be in there all summer depending on, you know, lake. But oftentimes they, they slide off in the mid hot summer months, but they’ll return back in the fall when water temperatures drop, oxygen levels go up and those fish can come back safely in the shallow water to bulk up for winter. 2 (30m 30s):
That’s where we spend as five fishers. Definitely the majority of the, of our fishing time is somewhere on that shoal, be it five feet of water or 21, 22, 23 feet of water. And you know, that’s the prime area is that we spend the bulk of our, our fishing time on. 3 (30m 51s):
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Episode is brought to you by Grand Teton Fly Fishing. They’re a top guide, service and fly shop with access to some of the most prized waters in western Wyoming. And their guide team brings together over 200 years of local experience. Their goal is simple to share these amazing resources and help you experience the thrill of a native cutthroat rising to a single dry fly all in the shadows of the Tetons. It’s the kind of experience that stays with you and fosters a deep appreciation for the waters we love. You can check ’em out right now at grand teton fly fishing.com and if you book a trip, let them know you heard about them through this podcast today. 1 (32m 24s):
That’s the place to be, isn’t it? That’s why my podcast is named La Toro Zone. ’cause from a Stillwater perspective, that’s the place to be. That’s where the food is, that’s where the fish is and that’s where we’re probably best suited to fish there too, aren’t we? With all our different techniques and, and gear options and things like that. 2 (32m 42s):
Absolutely. So once we leave the la Toro or Shoal area, we’re out into the Midwater Lake, which is called the Matic Zone. So it’s the open water part in middle of the lake. So the still penetrates down to the same depth out there as it did in the in shoal areas, but there won’t be any vegetation growing ’cause we’re in the, into the deep water area of the lake. And the sunlight can’t touch the bottom, but it impacts zooplankton on and how much is in the lake and its movements up and down through the water column because zooplankton is photo sensitive and as you I know trout love to eat zooplankton like Daphne Cyclops buzz mine and those types of species. 2 (33m 33s):
And that’s why we, we like to fish those blob patterns and 4 (33m 38s):
Yes we do. 2 (33m 41s):
And then that’s why they could be be so effective. So there’s a fewer diversity of food sources out in deep water over the tic zone. But ones that are important not only include zooplankton, but we have deep water cronin or mid hatches that could be coming off in as much as 90 feet of water common in 30, 35, 40, 50 feet of water. So remember these lakes got that nice mud bottom way out in the middle. It doesn’t matter whether we’re in five feet or or 45 feet of water. So it’s prime habit habitat for those chron larvae to be living in the mud at those depths. 2 (34m 24s):
And so you can get, you have some fabulous deep water chron fishing out in that deep clear tic zone and the fish will get pushed out over the edges of the dropoff during the worry warm summer months, if the water gets too warm on the shoal arrow zones, they have to slide off onto the edges of the dropoff and then out into the, the deep water zone or, or the magnetic zone because they can get down to depth where the oxygen is more conducive and the water is cool and they just hunker down there and, and wait for the literal zone water to cool off in the fall. 2 (35m 6s):
But they don’t quit feeding. And that’s why we’ve spent so much time experimenting with blob patterns to try to imitate those different species of, or different colors of zooplankton that are found out there. So that also can be a very, very important area of the lake for fish to be in and to also to fish in and that but more restricted to the warmer summer months. And then lakes also develop thermo climbs in the warmer summer months. So that sunlight that’s penetrating down to seven, eight meters depending on water clarity, it’s beating down there and it’s warming those upper layers of water. 2 (35m 52s):
It’s warming them up. But below the energy of the sun’s penetration, the water remains cool so that there’s a transition zone that, that’s called the thermocline. It gets established on most atrophic lakes and it’s where you reach the end of sunlight penetration and heat and meet that cold water. It’s often a band of a narrow band of water that’s rapidly dropping in temperature. It’s usually up to about a meter in depth that zone. And that’s the transition between the warmer upper layers of water and the deeper cooler area of water. 2 (36m 37s):
And we call it thermocline. So the thermo climbin can act as a invisible barrier to mixing. It’s that that rapid drop in temperature over that very narrow depth can be a, a barrier to mixing. So the wind can blow hard during the summer months and it will only mix the water from the thermocline and above. And the deeper colder water resists the mixing because of that temperature gradient. And it remains cooler all during the summer months. So when the water gets hot, those fish slide off the shoal areas, the warm shoal areas and sit right above the thermic line where the water’s cooler and that are oxygenated so it can blow and blow and blow in and it will not break down the thermocline and cause mixing. 2 (37m 33s):
It’s a very strong barrier that is resistant to mixing. So we find thermocline establishing on most atrophic trout lakes, however, there’s always exceptions to the rule and lakes that are very, very shallow, like 25 feet in depth and less, they’re often shallow enough that, and in windy locations that that the thermocline never really gets established because the energy from the wind is enough to keep it mixing. And so what safe to say that 90% of the lakes trout lakes are well developed, the McCline there, there’s always gonna be ones that don’t. 1 (38m 13s):
Yeah, we, I can think of some of the shallow ones, you know, up near your neck of the woods as well that are, you know, that’s the deepest spot. 1820 feet, those lakes never, you know, the, the lake can’t stratify thermally. So the the, I think it’s important that the thermocline can’t form because the sun’s raised. The sun’s energy can impact that lake water from the surface to the bottom. And you can also get thermic lines forming in a li atrophic and Oh yeah, me atrophic lakes as well. Absolutely. Because it’s all about the sun’s energy, right? Yep. Okay. They form 2 (38m 44s):
In the biggest lakes, smallest lakes. And so me atrophic oli atrophic lakes definitely form thermic climbs and there will be a gradient temperature gradient there. But those big ocean type lakes, they regularly break down the thermo climb because of the energy of that water moving through the waters enough to break it. 1 (39m 8s):
I’ve seen some videos where it shows how when wind gets going, that whole thermo cline sachet, right, the whole lake sort of tipping from one end to the other. But the thermic cline remains intact because the energy isn’t there to really pound it and break it up like you talked about. So you could have the therma cline deeper at one end of the lake and shower the other, depending how the wind’s blowing and the water’s think of a bathtub, right? I guess just sloshing up and down, left to right kind of thing. As that happens, 2 (39m 37s):
That wind, wind sach where water’s pushed to one end of the lake and then it rocks back and forth. That’s why you could be out there fishing one day and the wind is glowing, downwind, yet your indicator is coming, drifting back towards is because there that wind that’s hit the other in the lake and it’s now sending a curb to water back. 1 (39m 57s):
It’s undertow, it’s circulating back under that, grabbing everything and you’re going, what’s going on? And you set on it every realize there’s nothing there. Yeah. It’s pretty interesting to see. And so fish can go out and slide there. They don’t necessarily, I think some people may think that when a, a trout leaves, you know, the shallow, the shoal area, the toal zone and heads out to deep water, it doesn’t just go over the drop-off and plummet right down to the bottom. Does it, they can slide horizontally out there and stage. I think you’ve talked to me about it with your forward facing sonar you have now, which I am envious of. You’ve seen that right fish staging out in in mid depth just, you know, not happy with the shallow area and just hanging out there until they are happy to go back in the shallow area again. 2 (40m 39s):
Absolutely. And in many legs, even though there’s a thermocline and so there’s no mixing below the thermocline. So in some of the most productive like shallow lakes, there can be a loss of oxygen under the thermocline during the summer months because there’s always anaerobic decomp occurring, which is stripping wa oxygen out of the water. But in most atrophic lakes, there’s still enough oxygen below the thermocline for those fish to be feeding on those deep water chron hatches. ’cause you might say, well you said earlier there’s chron hatches in 60, 70, 90 feet of water. 2 (41m 22s):
Well the, and they oftentimes it’s during the summer months when those occur. So there is enough oxygen below the thermocline and the majority of those trout lakes for those fish to be down there feeding on those cid larvae and emerging pupa. However, some of the most super productive trout lakes, there may not be enough oxygen below the therma line for those fish to be comfortable and to feed. And that’s why they sit just above the thermocline in, in a layer where the water’s cool and better oxygenated. And that’s where your, your, your depth sounder becomes such an important tool to understand what’s happening in the lake. 2 (42m 6s):
It, it can tell you so much. Oh, oh, why are all these fish sitting here and there’s none deeper? 1 (42m 12s):
Yeah, well you can actually see the thermocline. Yep. I have on my sounder because of that differing density of water due to the therm, you know, the temperature differences part of that sounder pulse penetrates through and actually hits the physical bottom. Whereas part of it is reflected off of that. And it looks this distinct line at a set depth, you know, as you said, depending on water clarity, 20, 25 feet, maybe a little deeper in clearer lakes. And it looks like a blizzard south of that point, doesn’t it? That’s where the thermocline is. And of course you said zooplankton like stacks up there as well, right? It’s not physically strong enough to penetrate that difference, is it? 2 (42m 49s):
No, no, that’s right. 1 (42m 50s):
So there is a, a term for the zone underneath the thermic line too, isn’t it? On, on larger lakes where it really establishes itself. 2 (42m 57s):
Yeah, it’s called the hypomon and the, the bottom of that deepest part of the lake. It’s the pro fundal zone of, of the lake. And so if you’re reading, if some of our audience members are looking up biology, water chemistry books or about lake ecology, you’ll the, all these terms will, will pop up and hopefully you’ll have a better understanding. 1 (43m 25s):
Yeah, okay. Yeah. ’cause there’s one you and it is interesting ’cause the genesis of this podcast is when I was doing my, my book, the Orifice Guide to Stillwater Trout Fishing, I had to write one chapter and send it to the publisher right away. I think doing, in part they wanted to see if I could string three words together and make a sentence. But the one I wanted to do was sort of the elephant in the room, the one that was most technical and that was, you know, how lakes work and you were gracious enough to proofread that for me and make sure I had my science and my theories in line with reality. And so I thank you for that, but it’s such critical information to know. 1 (44m 5s):
So that’s a great place to find that as well as other books. Is that, what’s that really big? It’s by, is it by Weell Limnology? It’s a university book text. 2 (44m 13s):
Oh yeah. That by what? Oh yeah, that’s the, the gold standard Limnology textbook. But you know, listening audience, they should just buy your book. 1 (44m 24s):
Yeah, well good working knowledge. ’cause I did reference that book in addition to your volume of knowledge as well. And it’s a, it’s an expensive book ’cause it’s, you know, limited print run being a, a university text and it’s, if you want to go down the limnology rabbit hole, that book will take you there. You’ll, I recall reading pages of it and then stopping after about half an hour going, I, none of that stuck in my head. I gotta go back again because it was like what? Yeah, so I guess you don’t have to know all that much, but it’s important, right? Because it helps you determine where to go. And I think, you know, to, to summarize this podcast, the toal zone, the shoal areas where we wanna be is fly fishers and that’s the, the shallow area of the lake where the sun can hit the bottom. 1 (45m 6s):
You’re gonna see weeds there, you’re gonna see all your majority of your insect hatches. It’s the place to be in the spring and the fall months and into early summer before the late. You know that, as you mentioned and we’re sort of treading the border here between our next podcast we’ll get together for on, you know, the seasons of a lake. ’cause some of these are gonna cross in when things like turnover and, you know, the summer doldrums and all that stuff happens. We also like the transition areas, don’t we Brian? The drop offs, the points, those kind of structures. Sunken islands. 2 (45m 39s):
Yeah, no, I think once we get together for our next discussion, it’ll, it’ll really tie everything together and hopefully provide lots of tips for all the, all the ardent still water fly fishers that are listening to our talk. 1 (45m 58s):
So to summarize what we’ve talked about here, roughly in an hour, all lakes are different, aren’t they? 2 (46m 6s):
Absolutely. 1 (46m 8s):
Yeah. You can’t broad brush them, you know, geographically we talked about pH because that’s, you know, one of the criteria for breaking lakes down into whether they’re a li atrophic, me atrophic or atrophic, we wanna spend our time, we wanna look for those shallow, productive lakes because they make the best trout lakes. If you’re a bass fisherman, they make the best bass lakes because of the, the amount of food they can hold and the fish they can grow. And I think we mentioned a number of times as well, it’s generally the shallows of the place to be because that’s where the plant growth takes place. The food lives there and the predators come in to feed on it. And as fly fishers, we can use a variety of techniques to successfully fish that zone indicators, long leaders, sinking lines, sweep lines, all kinds of things at our disposal. 1 (46m 54s):
Right? 2 (46m 55s):
Yeah, yeah. No, it’s great. You know, the, as we’ve always talked about, Phil, you know, every day on the water we learn something, but before we’re going on the water, if you’ve got a, that basic understanding of lake structure and how lakes function, which relates to where the bugs are living and how they’re ing and where you should be fishing, it just, it just makes your day on the water that much more enjoyable. 1 (47m 23s):
Yeah, exactly. Well Brian, I appreciate you taking the time today to talk to me about this stuff. Hopefully everybody enjoys it and learn something from it and the importance of it. It may get a little sy and a little like, why do I need to know that? But you do and I look forward to getting together with you again. We will talk the seasons of the lake that’s really gonna bring all of this into focus and really understand where we need to be in lakes at certain times of the season. So thank you very much Brian, and hopefully you can still get out on the water. We’re recording this in late November. Brian’s got the benefit of a few lakes at lower elevation lakes that are, are still open. 1 (48m 4s):
Mine are locked up and I’m done till spring of next year. So 2 (48m 11s):
Yeah, I, we’ve got a little bit of time left, but it’s definitely nearing the end. 1 (48m 17s):
Alright everyone, thanks so much. Thanks for listening and we’ll see you, we’ll talk to you on another podcast. I hope you enjoyed today’s episode. The first in my two-part series focusing on how lakes work. I always enjoy talking with Brian about all things to do with Stillwater. This was Brian’s second time on my podcast. During our first episode, we discussed one of our favorite passions ate. Be sure to check out that episode if you haven’t already. Some of the key takeaways from today’s episode include understanding that all lakes are not created equal. Each lake is its own unique environment pH potential hydrogen in part is used to help determine a lake’s trophic status and is used to help classify all still waters as fly fishers. 1 (49m 4s):
We aim to target trout in the most productive lakes or atrophic lakes as they’re typically home to large trout. Brian and I also discuss the different zones within a lake where they’re found and which zones trout frequent at various times of the season. And why be sure to listen to part two of this series.
To wrap up today’s episode, not all lakes are the same. Each one has its unique environment. Be sure to listen to part two of this series for more insights on how lakes work.