Above Barriers

I recently spent a few days in the northern tier of Pennsylvania camping and fly fishing for wild native brook trout. Once again, I was discouraged by our inability to avoid catching nonnative trout. Where I live in south-central PA, my county is full of wild brown trout. In fact, aside from 2 or 3 streams in the entire county, every cold-water trout stream is full of brown trout and nothing else. Many of these streams hold large wild browns, and they’re challenging to catch. If I wanted to catch brown trout, I’d drive 5 minutes down the road, not 3 hours north.

PA Native Brook Trout

I’ve heard all kinds of stories about brown trout being shipped by rail car to remote areas of Pennsylvania as far back as the late 1800s. The theory is that those brown trout were introduced to isolated areas long ago, and the brown trout you catch today are descendants of those early plants. Somehow this is used to justify their existence or suggest that they’ve been here for a long time, and are therefore somehow part of the environment.

I have several issues with these theories. First, regardless of when the fish were stocked, they’re nonnative and cause harm to native brook trout. Second, I’ve seen enough evidence of more recently established populations to know that it’s highly unlikely that most of the wild brown trout you encounter are descendants of fish that were stocked in the 1800s.

As an example of where this theory falls apart, think about a watershed like Moshannon Creek in central PA. Most historians point to the early 1900s as the point at which mining operations in the Moshannon Creek watershed polluted the mainstem and killed most of the aquatic wildlife in the river. Brown trout were imported from Europe in 1886, and supposedly shipped to every corner of Pennsylvania. In upper Moshannon Creek, there are no brown trout in the clean waters upstream of the first pollution inputs. If brown trout were stocked far and wide, why aren’t there any brown trout in the headwaters of Moshannon Creek?

The other theory about brown trout being present in remote areas of the state is that they travel via large rivers and populate every stream without a barrier. Again, Moshannon Creek was likely cut off from the West Branch of the Susquehanna sometime around 1907. A good 21 years after brown trout were introduced far and wide. Given Moshannon Creek’s proximity to the early fish hatcheries and likely initial stocking areas, I find it hard to believe that no brown trout made it up Moshannon Creek before it was polluted.

If the theory about the widespread presence of brown trout is that they were spread everywhere early, why are there streams that have been isolated fairly recently that don’t have any brown trout?

The image above is at the mouth of a small brook trout stream that flows into a larger tributary to a larger river. The mouth of the stream is full of large waterfalls and obstacles to trout passage. This is in a fairly remote area, though there is a sportsman’s club right at the mouth of the brook trout stream.


The photo above is a bit deceiving as the nearly vertical waterfalls are almost 5 feet tall and some of the areas are undercut, so they’re not steps, but rather a 5 foot high ledge with water dropping straight off the lip of the ledge. The tree across the top of the photo is almost 2 feet in diameter for reference. These barriers would have been extremely challenging for brown trout to navigate. Conventional scientific research suggests that barriers like this serve as a natural deterrent to the ingress of brown trout. So there shouldn’t be any brown trout above this series of waterfalls.

I wasn’t in the least bit surprised to find wild brown trout above those falls. I don’t believe for one second that brown trout navigated the 5 foot vertical walls of water, or that some ancient train in the late 1800s deposited some german trout in this tiny stream. The presence of brown trout in this little brook trout stream is the direct result of people moving them there much more recently.

This issue exemplifies the problem with the mixed messaging coming out of the Pennsylvania Fish and Boat Commission. The state continues to stock brown trout in brook trout streams far and wide. We have more protections for brown trout now than we do for brook trout. The state recently introduced a proposal to make brown trout catch-and-release in stocked Class A waters. If that passes, we will have a trout-species-specific regulation to protect a nonnative species that is responsible for displacing and the extirpation of brook trout.

When you tell people that these fish are important and they belong everywhere, people will start moving them around to places they don’t exist. Absent any messaging from the Fish & Boat Commission telling people not to move species around, that’s exactly what people are going to do. Throw in the mixed messaging on invasive species, and you’ve got a confusing mess for the public to try to understand.

Combine the lack of messaging, widespread stocking of nonnative trout over top of wild native brook trout, and protections for nonnative trout with a lack of messaging or information about the status and threats of brook trout, and we’ve got a recipe for disaster. The state has thus far shown absolutely zero interest in removing nonnative brown or rainbow trout from brook trout streams. So once these fish end up in a brook trout stream, they’re likely there to stay forever.

Does the above stream look like the kind of place you’d expect to catch brown trout? It shouldn’t as it’s a brook trout stream. Yet brown trout are now throughout this stream thanks to the hands of man. We don’t need brown trout in every single stream in this state. As you can see from the image above, these brown trout aren’t any larger than the native brook trout they’re replacing. We’re just exchanging our state fish for an import from another country.

This blog was largely born out of the stark realization that you have to go to great lengths in Pennsylvania to find a brook trout stream that has no brown trout in it. Every brown trout in a brook trout stream represents a loss of brook trout. Streams can only carry so many pounds of fish per mile, and you can’t add a new species without subtracting the native species. So even if the brown trout haven’t completely displaced the brook trout, they’ve displaced individuals by taking up prime feeding lies, cover, and resting habitat. The combined effect of that displacement is likely in the millions of lost brook trout throughout the state.

Unfortunately for myself, I can no longer simply catch a brown trout in a brook trout stream and think nothing of it. Every single brown trout I catch in a brook trout stream is a jolt to my system and an unfortunate reminder of how much we’ve lost, how far off track we are, the confusion the public has about the issue, and the lack of focus by state agencies, non-profits, and the public at large.

Categories Musings

2 thoughts on “Above Barriers

  1. Nonewhere Listens 05/07/2023 — 7:27 am

    Curious- when you catch a brown trout in a brookie stream, what do you do with it?

    1. That depends on a lot of factors. In streams with a fairly significant population of brown trout, I simply release them. There would be no point in trying to single-handedly remove brown trout from a stream that they’re well established in. In streams where brook trout far outnumber brown trout and I only catch one or two browns to every 20 or 30 brook trout, it depends on the season, and my time. I do harvest browns and cook them streamside or bring them home in some cases.

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