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Migratory Browns

The hunt for giant salmo Trutta.

Migratory Browns

”Migratory trout make the journey from oceans, reservoirs, and lakes into rivers to spawn and feed. Depending on the reason for migrating, these large targets can remain in the system for a short time, two to three months, or in some circumstances, half a year.”
—The Hunt for Giant Trout (Stackpole Books 2019) (Landon Mayer photo)

Brown trout are the most accomplished disciples of Sun Tzu’s Art of War (Trout Edition). When another species of fish is superior, brown trout evade. When another fish species is weaker or smaller, they attack and consume. Giant Salmo trutta are the cleverest survivors, and holding a giant specimen of the trout that formed the roots of our sport is simply magical.

On my most recent trip to the Great Lakes—with friend and fellow guide Zack Tokach—we decided quickly on a fall trip after a change in weather introduced much-needed moisture across the Midwest. This is an important requirement for migratory fish, especially in small spate streams that are dependent on recent rains for much of their flow.

Migratory brown trout
When rivers and streams are low, trout in lakes gather near the river mouths as they wait for rising water and patrol for food. Author Landon Mayer caught this big brown in a South Park reservoir before the fish started its fall journey. (Michelle Mayer photo)

I had fished this same region in a previous year and had success fishing right in Lake Michigan because the local river water levels were extremely low. We started our 2020 trip also fishing in the lake, but happily realized that the trout had followed the rain and moved into the tributaries.

The next day we started on the largest tributary in the area. It had recently increased in flow to 200 cubic feet per second (cfs), and we hoped it would provide some shots at new fish swimming up from the lake. After a few hours, I had the gut feeling that something was off. We hadn’t seen much of anything.

So we took a 40-minute drive to a much smaller tributary that also got a lot of rain, but now was falling. That surge of water with dropping, clearing water created a magical condition that rewarded us both with browns over 20 pounds, and my largest was more than 36 inches long. I love it when a plan comes together!

Giant Genetics

Our big trout in 2020 were a particularly hardy strain of Seeforellen brown trout (Salmo trutta lacustris) that were introduced to Wisconsin in 1991. Seeforellen is a German word that literally translates to “lake brown trout.” This subspecies lives a year or two longer, and spawns a month or two later in the fall compared to other strains of brown trout in the Great Lakes. The current Wisconsin state record is a 41-pound, 8-ounce Seeforellen brown caught in 2010 by Rodger Hellen.

Both male and female trout have the potential to grow large, with females often winning at the scales due to the mass of eggs in their fat bellies. Males are prone to be longer and leaner. Migratory trout coming from the ocean or the Great Lakes are built like muscles with paddle-size tails, while the tailwater trout I chase at home in Colorado have big, sagging bellies.

There is a huge difference in behavior from male and female trout, most importantly when the migration season is near. Leading up to and during the spawn, female trout tend to be a bit more passive, waiting in deep runs in preparation to drop their eggs on suitably prepared gravel. Males at this time can be insanely aggressive, fighting against other males to defend the best water, or to fend off other males from mating with the large females. Trout that migrate into rivers in search of food can be equally aggressive—sometimes they act like a pack of wolves, biting at one another to defend the prime feeding zones and food to themselves.

Male trout are the first to enter prime water or migrate as the spawn is near. If flows are adequate, they can be in the river two or three months before they actually spawn.

In this pre-spawn stage, the big males are aggressive and ready to attack while they wait for a suitable female to show up. This is one of my favorite times to throw streamers to trigger aggression for big trout. These giants are on edge, and very aware of their surroundings. It’s the best time for the fish to see your flies and react.

Resident or Migratory

It is important to figure out whether the trout you are pursuing are migratory or resident trout. Resident trout are familiar with the water. They have their favorite hiding spots, and their body color and markings are designed to prevent predators from seeing them. In some waterways, like Lake Ontario, Lake Michigan, and Lake Erie tributaries, brown trout can appear almost black on the belly and fins because they match the dark river bottom.

Have you ever noticed how a brown trout fin looks like a potato chip? In my book Sight Fishing for Trout (Stackpole Books; second edition 2019) I recommend looking for these “chips” along the river and lake bottoms. When trout feed, they flare out their fins for stability, giving you a visual cue to help locate your target.


When fishing for large resident trout, I really focus on the fish’s food supply to get them out of hiding. This is when a heavy hatch, hopper blown off the bank, drowned mouse, or dead-drifting baitfish can produce a fish of a lifetime because these resident trout are always home and they recognize the dinner bell when you ring it.

Migratory browns are a different animal. They come from dark places like oceans, large lakes, and deep reservoirs. They are new to the river, and the biggest difference for them—apart from the current flow—is the bright light. In a lake, you can merely swim 10 feet deep to avoid the sun, but in shallow rivers, it’s much more difficult. Trout don’t have pupils to limit the amount of light entering their eyeballs, so they don’t feel comfortable in clear, shallow water with bright sun. We have all sat in a dark movie theater and been blinded when we step outside. That’s how it is for these trout.

Most of the big trout I have caught or my clients have caught were not hooked in bright, sunny conditions. If you want to catch really big migratory brown trout, you must use dark stormy skies, dirty water, dusk and dawn, and rain and snow to your advantage. This is also true to a lesser extent for other migratory fish like steelhead and salmon, but I believe brown trout are the most light-averse of all the salmonids.

Compared to resident trout, migratory trout hold in the most bizarre locations. This used to confuse me until I started looking at the river like a highway, and began imagining the routes the fish might take upriver, and where they might pause along the way for rest and security. Not only does this show their migration path, it allows you the chance to look for cover zones and feeding lies that might be overlooked. Unlike resident trout, they do not know that the 18 inches of riffled water along the river edge leaves them exposed. They simply stop because they cannot see past the distorted surface, and it feels safe. Sometimes they find these places at night when they migrate, and they won’t move unless you or the sun chases them out.

It is surprising where these tanks sometimes hold. It can be on the edge of the river next to an undercut, at the top of a run in 18 inches of water, or in the middle of the river in a slight depression. Even if a boulder is only three feet wide, or if a bank is undercut by a foot, it is enough to hide a 30-inch brown trout. I know this not only from hunting these giants with the fly, but also from helping our local biologist electroshock the South Platte River. If you ever have the chance to do this, don’t pass it up. It is a great way to help give back to the resource, and it allows you to see the true potential of the water, and learn where these monsters hide.

Migratory brown trout
Even when migratory browns are not feeding, you can elicit a territorial or instinctive reaction from the trout using streamers and swinging and/or stripping techniques. (Jessica Delorenzo photo)

Go with the Flow

One thing you learn right away when hunting migratory trout is the importance of watching stream flows and reservoir or lake levels, as this can be a big indication that conditions are right for the hunt. In small tailwaters and on freestone tributaries the flow rate is measured in cubic feet per second (cfs). You can get the current stream flow at, and you can generate charts showing recent or long-term history. The information comes from stream flow gauges on thousands of U.S. streams and rivers. All tailwaters below dams have stream flow gauges. Some small freestone rivers may not have gauges, but you can use nearby gauges on similar streams to get a sense of whether your river is rising or falling and by how much.

Before and during the spawning season, trout wait for a spike in stream flows to allow them easy passage upstream over and around barriers, and with less threat from predators. Some of the streams they move into are small, insignificant tributaries, and the trout avoid migrating in belly-scraping conditions. They wait for high water. Some trout still migrate in low flows, but the numbers are lower and they do it mostly at night.

Water temperature may be just as important as stream flow. In the summer, many of these tributaries are simply too warm. Early in the fall these small streams cool quickly into a more favorable range, but warm water along the lakeshore can still act as a barrier for weeks. Temperature can also be a trigger in the spring when large lakes and reservoirs are extremely cold (or frozen) and the tributaries break open and begin to warm.

When Mother Nature shuts the valve off, and the rivers drop dramatically, you’ll want to target the inlets and edges of lakes and reservoirs. Whether it’s the shoreline of Lake Michigan, or a shallow bay in Spinney Mountain Reservoir, trout in lakes gather near the river mouths as they wait for rising water and patrol for food. To catch fish in the lakes, I look for sharp contour lines and drop-offs, interception points such as rock jetties and peninsulas, and structures like weed beds that offer both food and security.

The key to stillwater fishing is depth control. Whether you are sight fishing, or casting into dirty water or with low light, you have to present the fly at the level of the fish. You also have to make the presentation without spooking the fish, and it should appear natural.

For deep water, I like to suspend my flies below a large foam Air-Lock or slip indicator. In shallow water, I use a small, clear Thingamabobber or a large buoyant dry fly as both an indicator and a suspension device.

I try not to do a lot of casting because it often spooks fish. I also don’t like to do a lot of retrieving because you’re in and then out of the viewing lane too quickly. Stillwater trout don’t like to chase their food. I choose flies that have inherent mobility—they get strikes even when they are barely moving. The gentle up-down movement of your indicator is all you need to bring a Balanced Leech, Mini Leech Jig, or Mini Leech Jig Damsel (#10-16) to life.

I learned how to be more effective in stillwaters after fishing Pyramid Lake in the spring and the fall for more than a decade. The same tactics work at home on the reservoirs of the South Platte River drainage.

In deep open water or deep drop-offs, you can’t efficiently cast a leader that is long enough, so I switch to a Scientific Anglers Sonar Triple Density sinking line with three sections of int/sink 3/sink 5. The sink 5 portion is closest to the fly, and this design prevents belly sag and helps the fly get to the correct depth on a straight line. I connect a 2-foot piece of 0X fluorocarbon to a micro swivel, and attach a second 2-foot piece as a tippet to attach to the fly. In open water I use the countdown method to find the correct feeding depth.

One thing you learn right away when hunting migratory trout is the importance of watching stream flows and reservoir or lake levels, as this can be a big indication that conditions are right for the hunt. In small tailwaters and on freestone tributaries the flow rate is measured in cubic feet per second (cfs). You can get the current stream flow at, and you can generate charts showing recent or long-term history. 

Following the Food

Giant brown trout make the journey from reservoirs, lakes, or large bodies of water not just to spawn but also to feed, and they can migrate back and forth and in different seasons. Depending on the fishery, migratory fish can be in the river up to half the year. In the fall, brown trout feed on the eggs of spawning salmon, and in the spring when the creeks are high and slightly warmer than the lakes, many types of baitfish and other food sources make their own migrations, and brown trout follow them. To learn more about these important food sources and how to imitate them, read Kevin Feenstra’s Matching Baitfish: Patterns and Techniques for Great Lakes Steelhead and Lake Run Browns (Stackpole Books, 2020).

“As you first approach a river or research it, you might look at the available food sources and determine which ones the gamefish might be eating. If you are streamer fishing, look to the bottom-dwelling baitfish that are in most rivers. They are a size that migratory fish like to eat and are found just about anywhere that has a few rocks. Furthermore, they are foods that are familiar to gamefish out in the Great Lakes. Large, fertile rivers have a lot of different food sources to choose from, whereas smaller, colder rivers have less. Rivers with poor water quality might be lacking baitfish, but that’s OK because the migratory fish that are present will be hungry,” Feenstra writes in Matching Baitfish.

“During the fall months, color is typically more important than matching any particular baitfish with your fly. That being said, if you fish a lot, you will encounter a day when the fish aren’t particularly grabby. This usually falls in line with a strong weather event or rapid changes in water depth and clarity. It is during these poor bite periods that a natural pattern might take the one biting fish. Furthermore, even when using bright and gaudy patterns, the shape of the fly you tie on can help you be a more successful angler.

“Some parts of our rivers have large congregations of shiner and chub minnows in the fall, and migratory fish will feed on these. I have seen steelhead and brown trout crashing these minnows in the mouths of our rivers, and there are many of them in other parts of our systems as well. A good shiner imitation will take a fish readily at this time of the year.

“Migratory fish may pass upstream slowly. Delayed by low-water conditions, they might concentrate in these lower reaches of a river system for quite some time.”

Use Feenstra’s book to help you identify locally important food sources like crayfish, sculpins, alewives, shiners, and chubs. Your next step is to find the most logical places for giant trout to consume these meals while expending as little energy as possible.

I most often find these big fish by using streamers; swinging streamers to big trout I can see or to water I think they are holding in, or stripping streamers back to the boat, or around woody structure or boulders.

It’s always prudent to start you fly selection based on the available food sources, but I also believe that these predators are so territorial they will chase and bite a fly even out of instinct, even when they are not actively feeding. I saw this many times on Navarino Island, in Patagonia, where browns moved into small rivers from both headwater lakes and from the saltwater estuaries.

We used trout Spey techniques to swing our flies in narrow, swift streams, and most of our hits came from browns holding in the seams between fast and slow currents. I saw little or no signs of feeding trout, but these migratory browns rarely refused a #4-6 Chocklett’s Finesse Game Changer, Lynch’s Drunk and Disorderly, #10-14 Mayer’s Mini Leech, or Johnson’s Sluggo, darting through the water.

Big, migratory browns have always been my favorite challenge, and that’s why I love fishing rivers and small streams that are connected to large bodies of water. There’s something special about catching giant trout in little creeks. Whether you’re in Patagonia or Wisconsin, the same principles hold true. Chasing these fish makes you a better angler and sets you up to catch other migratory species like steelhead or striped bass using similar strategies. As with all puzzles, it’s the process that’s important, so take your time to study the flows, research the baits, tie the right flies, and be in the right place at the right time. Above all else, enjoy the journey!

The Origin of Brown Trout

Migratory brown trout

Much of what I know about the origins of brown trout comes from Matt Supinski’s book The Brown Trout-Atlantic Salmon Nexus (Skyhorse, 2018). These hardy trout appeared at the boundary of the Eocene and Oligocene ages—a time when glacial sheets were receding, leaving behind the lakes and rivers in the Northern Hemisphere that we know today.

“Once brown trout established a dominant inland river and lake niche, their inquisitive migratory natures had oceans and seas at their disposal, which eventually developed a strong urge for them to be migratory nomadic wanderers, adapting an anadromous lifestyle, far away from the small gentle streams and brooks of their Salmo birth. Here they relished their newfound deep-sea environments to grow large and strong, and feed on the bounty of pelagic (Greek word for “open sea”) baitfish and rich crustaceans. Their great swimming agility could reach thirty miles per hour as Salmo salar, though sea-run browns were slower homebodies,” Supinski writes in his book.

“They eventually crossed hemispheres to establish colonies in what would eventually become the Americas. Their mocha orange and colorful mosaic red and dark spotting gave way to a sleek sheen of silver, aqua blue with a gunmetal gray back. This deep ocean translucency attire gave them the predator cloaking that made them such proficient hunters of the seas.”

Supinski explains that while the British had been exporting browns all over the world for quite some time, it was actually brown trout from Germany that were first planted in North America—in the Pere Marquette system in 1884.

“In the years to follow, Derbyshire and Scotland soon got in on the act with their stunning Loch Leven strain. Here was a big water lake or loch trutta that had more silvery coloration, larger and less spotting, and were known to be great migratory fish. Over the years the two strains spread throughout the East Coast and North America, both on the state and federal level. Both in the wild and in the hatcheries the two strains intermixed their genetics, leading to the great diversity of the American brown trout today.

“By the early 1900s, the brown trout had taken hold in almost forty U.S. states and Canadian provinces. The perfect wild frontiers of the rivers of the Rocky Mountains, Montana, Wyoming, and Colorado became ideal new frontiers for the elusive trutta. With their cunning ability to adapt, they took hold in every stream and postured themselves as the alpha fish in every pool and riffle in every tributary or main river.”

Landon Mayer is a Colorado fly-fishing guide and Fly Fisherman contributing editor. He lives with his wife Michelle and their four children in Florissant, Colorado. His most recent book is The Hunt for Giant Trout: 25 Best Places in the United States to Catch a Trophy (Stackpole Books, 2019).

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