Does a Stocked Trout Ever Become Wild?

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“Once a stocked trout is in the river for a while, it becomes just like a wild one.” I hear this idea a lot. Anglers of all experience levels have levied this argument, likely from the time stocked fish were first planted in a river. It’s the premise that stocked trout adapt to their surroundings, that they take on the characteristics and habits of their wild counterparts. But is this true? Is it, really?

No, it’s not. In short, stocked fish are stocked, and there’s no amount of time in the water that changes that.

Now, I’m well aware of the dissenting opinion. It’s a popular one. I’ve heard it a lot and understand the argument. But I don’t buy it — not because I’m guessing, but because of what I’ve seen and experienced over decades on the water. I’ve caught a lot of trout, both wild and stocked, and there’s a clear difference between the two.

It’s not all that complicated, really. Stocked trout are a different animal, and they tend to stay that way.

It all begins at the genetic level . . .

** Note ** This article has received some comments that miss the point. This topic here is about a trout. It’s not about a population of trout. Surely, we all recognize that the brown trout, introduced over a hundred years ago into various parts of the United States, are now wild trout. And they act like it. That’s a good example. But again, this article is about what happens when a trout is stocked in a stream. Does that one trout take on the characteristics of a wild fish?

It’s in the Genes

The best wild trout come from a gene pool that has existed in the watershed for generations. Perhaps it’s a native population of brook trout, present in the Appalachian streams since the last ice age. Or maybe it’s a strain of German brown trout, introduced to many American river systems in the late 1800’s. In both cases, these trout are wild. And their genes are largely unaffected by the progress and intrusions of mankind. The best wild trout populations are specific to their own river systems, and they’ve adapted to the seasonal highs and lows, to whatever the decades of chance have brought to the collective population. The strength to thrive and persist is in those wild genes.

Hatchery trout are the opposite of all that. Most stocked trout are from hatchery strains that have been genetically selected to grow fast and feed aggressively. Fish farming is a business. So hatcheries promote trout strains that live best in a hatchery.

These hatchery fish are the result of science. Hatcheries are prone to the outbreak of disease, because so many fish are in close proximity. They harbor schools in the thousands of trout per ten-foot-wide tank. So fish biologists select the trout most resistant to such disease. And these hatchery trout produce eggs for the next generation. However, the same strains, selected to thrive in a hatchery, are poor performers in the wild. The return on hatchery fish — the ones that make it through a full year — are shockingly low, even where they are protected by special regulations like catch and release. Conditions and rivers vary, but the estimated rate of return can be lower than five percent. It seems that stocked trout are ill equipped for a wild environment.

(For a thorough, science-based reading of the hatchery system in the US, and its history, check out Anders Halverson’s book, An Entirely Synthetic Fish. For even more reading on the subject, work through the contained bibliography.)

READ: Troutbitten | Clarity and Science about Wild vs Stocked Trout

Likewise, hatcheries do best when trout grow quickly. The faster a fish develops, the sooner it can be sent to the river. So biologists select the fastest growers to be the next breeders. What makes a trout grow fast? They feed aggressively. And that quality is nothing like our wary wild trout.

So then, stocked trout are genetically different than their wild counterparts. And they don’t become “wild” just by placing them in a wild environment. In fact, they usually die. But what of the ones that do adapt enough to survive? Don’t they learn to find natural food, don’t they blend in, learn the rules of the stream and become wild? No. Not really.

Buy An Entirely Synthetic Fish HERE

A stocked trout may hold over for years, and certainly, many do. But remember, the percentage is very low. Even when a trout does hold over, it never loses the propensity to feed more aggressively than a wild fish. And it also grows faster than its wild cousins.

Genetically, stocked fish are different, and that simply does not change. A German Shorthaired Pointer will never herd animals the same way an Australian Shepherd does, no matter how long you keep him on a farm with sheep and cattle. Likewise, the shepherd will never be the wonderful bird dog that the pointer is. The genes don’t change.

These days, some select private hatcheries focus on collecting eggs from pure strains of trout. In essence, they breed trout from wild stock. They may produce cleaner looking fish with more vibrant colors. So the trout look more wild, and when they are stocked, it may be impossible to distinguish a hatchery creation from the real thing. But while these fish are much closer to wild than their mainstream hatchery counterparts, they still suffer from the same fate as all hatchery trout — human, artificial conditioning . . .

Experience is the Best Teacher

A wild trout is born in the stream. The head and tail sprout from an egg into a form called an alevin — it looks very much like a tadpole. A month or more later, the trout is a full fledged fry — a small, inches-long fish trying not to be eaten by bigger fish. It learns caution. It learns to hide and be wary. And it learns the natural rhythms of nature, of the food cycle and bug life. It may even experience both drought and flood conditions in its first year.

These learned and imprinted behaviors of a trout’s early life can never be fully changed.

I encourage you to walk through a trout hatchery someday. (Many of them give tours.) When my boys were younger, we enjoyed taking a bucket of fish-food pellets and walking along the long concrete tanks, throwing a meal to the fish. I noted the habits of these trout. They ate quickly. They were competitive and very eager to feed. Notably, a human being walking overhead was a signal to feed, not a signal to dart away to the nearest undercut bank.

Even in private hatcheries, trout are conditioned for artificial feeding. And they’re conditioned to the protection that a hatchery provides. Likewise they learn to school up and feed in groups. Essentially, they are coddled and protected until the time they’re released into the wild. And I argue, emphatically, that a stocked fish never completely unlearns these early lessons.

Wild Trout. Photo from Bill Dell

The Life and Times of the Troutbitten Guy

I have a somewhat unique perspective on all of this, because of the places I’ve lived and the unusual amount of time I’ve been given for chasing trout. I grew up in western Pennsylvania, where acid mine drainage made the possibility of reproducing wild trout a thing of the past. (Some of these streams have since been recovered, and that is fantastic.)

So, I learned the habits of stocked fish, and I know them well. But I’ve spent the majority of my life, since about 1993, surrounded by wild trout and casting to them. I’ve tried to think like a trout and understand what, why and how they eat in these spring-fed waters of central PA.

I’ve also spent decades exploring every county in Pennsylvania, with a four-wheel drive, topographical atlas of the state and a list of trout waters from the fish commission. Along the way I’ve made a point to fish both wild and stocked rivers. And my experience teaches me, over and over, that stocked fish never become wild.

I fish some areas where the state stocks enough trout fingerlings (about five-inches) to maintain a decent population of trout in the river (even at low returns). And these fingerlings-turned-adults still feed differently than their wild brothers, many years later.

Our state now promotes what they call the Keystone Select Trout program, telling anglers they are provided a chance to catch “trophy” fish, stocked by the state. I’ve fished these locations. The trout are indeed large, and they are often attractive fish that look quite wild. But they are remarkably easier to fool than their wild brothers that reside just a few miles up in the headwaters.

In short, the longer a trout lives in a hatchery, the easier it is to fool.

Even after many years in the stream, a hatchery fish does not change much. My friends and I once caught the same twenty-inch trout six times, over a few seasons. When one of us fished the area, we either caught or spotted this trout. And I noted how differently it responded to my streamers. Initially, I believed the trout was wild, because it was in an unstocked river, surrounded by wild fish. But after multiple times catching this fish, and watching its aggressive reactions to poorly presented flies, I came to believe it was a holdover from a club that stocked and fed fish many miles below.

READ: Troutbitten | Why Wild Trout Matter

Just because you want to believe it . . .

Anglers tend to convince themselves of things they wish were true. You may want badly for that large Whiskey to be a Namer, so you make yourself believe it. And you keep the measuring tape packed away, because you’re sure enough that this one is a two-footer. We all know anglers like this, right?

But you can’t wish something into reality.

I meet trout fishers from all different parts of the country — some from places that harbor no wild trout or only small populations in isolated mountain streams. In these areas, the state often stocks hundreds of thousands of trout every year to create a trout fishery. It’s a manufactured scenario. And honestly, sometimes the fishing is fantastic. Anglers who fish these rivers might argue vehemently that their fish are “nearly wild” or “just like wild trout.” But if they visit true wild trout waters on a regular basis, they will see the comparison for themselves. When you fish for both, the differences are undeniable.

READ: Troutbitten | Wild vs Stocked : The Hierarchy of Trout in Pennsylvania

Stocked trout fisheries, especially those that feature large, “trophy” fish, may even train an angler to expect certain unnatural habits of a trout. Stocked fish often take attractor types of retrieves that simply do not produce over wild fish — not on any regular basis. I often mention this to my guests: Be careful what you learn from success on the river. Always consider what kind of trout you fooled and how you fooled it.

Come on, man.

Side Notes

I’ve written a lot about wild trout here on Troutbitten. And a good, long read through those articles reveals my strong stance for protecting and enhancing wild trout populations wherever they exist.

READ: Troutbitten | Tag | Wild vs Stocked

Stocked fish are a poor substitute for the real thing. And that will never change. They are genetically different, and they are conditioned to be different. Experience has taught me that none of that changes, no matter how many seasons a stocked trout may hold on.

I’m also against private clubs stocking over wild trout populations. It should be illegal. This practice is against our PA fish commission’s stated management policy regarding Class A Wild Trout waters. And I believe our fish commission should stop all stocking and feeding of artificial trout in wild trout waters. Keep wild trout wild.

The proliferation of stocked and fed club trout sets a dangerous precedent of expectations, especially for the new angler, who learns that big, fat trout can come pretty easily.

But I’m not against stocking, either. I’m thankful for the trout I grew up catching in western PA — the stocked rainbow and brown trout were in streams that could not support a wild population. Stocked fish certainly have a place. But they are not wild. And they will never take on the true habits of wild fish.

Fish hard, friends.

(I welcome your thoughts and opinions in the comments section below. Be nice to each other.)

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Enjoy the day.
Domenick Swentosky

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