Wild Native Trout: Surprising New Information About "Brookies"

(object thuds) (computer mouse clicks)

- Hi, Sanford Smith here with Penn State Extension.

Today, I'm joined by Jay Stauffer, and Jay is a distinguished professor of ichthyology at Penn State.

Ichthyology is the science and study of fishes.

And Jay, thank you very much for joining me today.

- You're welcome. It's great to be here.

- Jay, you've done work across the United States, you've done work internationally, but you also do a lot of work here in Pennsylvania.

And today's topic is on brook trout.

What can you tell me about the work you've done related to brook trout?

- Okay, a little bit of history about the brook trout.

It was described from a specimen from Long Island in 1815.

I worked a lot with Sara Mueller, who's my PhD student who recently graduated, and we sampled brook trout all through the state and we do morphology as well as genetics.

And we have determined that the original brook trout, scientific name Salvelinus fontinalis, has never occurred in Pennsylvania.

The only true brook trout that occurred in this state are hatchery trout that somebody put here.

- So what you're saying is the hatchery trout that are stocked here in Pennsylvania are the true brook trout?

- They are the closest we can get to the true brook trout.

We have genetic information that Tim King from USGS worked on.

He has a genome of all the hatchery brook trout, and they all originated from the hatchery in Bellefonte, Pennsylvania.

- Even though originally the trout came from New York state, was it?

- Yes.

- Wow, that's something else.

Now we call our little local or native brook trout brookies, or native brook trout.

So what are they, if they're not brook trout?

- They're in the same genus Salvelinus, and we will devise a name for them.

We haven't done that yet, there's several ways to do that, but we will eventually give them a scientific name and suggest a common name for 'em as well.

- Now also, I understand your research has shown that there might not just be one species of these little native brook trout.

- There may be several species in the state.

The work I did in Great Smoky Mountains National Park in Tennessee showed that there were three distinct species in the same drainage.

I don't think that's happened here, but we have to check to see if the population in the Delaware drainage and the Susquehanna drainage and the Alleghany drainage and the Great Lake drainages are different.

- That's fascinating.

So that's an interesting all in itself, but let's talk about a few other things.

So sometimes, I hear people talk about our native brook trout, and they say, "Well, you know, they really should be connected to the larger streams and such so that there's more breeding between the various trout in Pennsylvania." What do you think of that idea?

- I think that's a terrible idea.

I have no problem with people moving things above artificial barriers like dams or culverts.

That's fine, but when you look at a natural barrier that we see in the stream, a waterfall, there may be distinct populations above that.

They may be a separate species, they may not be, but there's certainly a populations that adapted to this environment.

I worked at the University of Maryland shortly after I graduated, and there was a stream there called Blue Lick stream that had a native population of brook trout.

The state stocked hatchery trout in there.

They interbred with the native population and wiped out the population.

And now the only trout that are in Blue Lick Creek are ones that the state put there.

So you don't want to move things above natural barriers, move fishes above them, destroy natural barriers.

And this whole idea of connectivity works against itself when you have unique populations.

- Yeah, and that's fascinating.

So that's the issue of connectivity.

Now there's the other issue of stocking over native populations, right?

So you have native populations in streams in different areas, and sometimes stocking occurs where people start introducing non-native trout or even other non-native fish.

What are some of the issues there?

- Certainly when we stock exotic fish such as the brown trout or the rainbow trout, they compete with the brook trout and restrict them to their range.

And this has been done all through the United States and certainly in Pennsylvania, but it's more harmful to stock hatchery brook trout because when you do that, if some of the hatchery brook trout survive, they can interbreed with the native brook trout and dilute the gene pool that's maybe adapted to this particular system for hundreds of years.

And when they do that, then the brook trout in the stream become less fit.

And we'll define fitness as how many genes you can pass to subsequent generations.

And if you destroy that fitness, you destroy their adaptability and their ability to survive in these unique habitats.

- Boy, that's fascinating enough.

Now we're talking about the problem of them interbreeding, the native brook trout, the brookies that are there, and with the hatchery trout.

What about other types of fish that might be stocked over them, let's say small mouth bass in some places?

- Certainly, smallmouth bass problem we're having now in lower Susquehanna River, the introduction of the flathead catfish, the blue catfish, and the snakehead, which are all invasive species, which certainly impact the populations of brook trout when they move into those streams.

There are also, when you have a cold water stream, such as the Youghiogheny River, and you have brook trout in the tributaries, those brook trout can move between streams, to streams during the cold winters.

And so it increases the genetic diversity of those streams, and that's a good thing.

But if the Youghiogheny River's full of flathead catfish, blue catfish, or snakeheads and they get eaten, it restricts the ability of the different tributaries in the Youghiogheny to share gene pools and to increase the diversity.

- Wow, this is fascinating, Jay.

I suspect we're blowing some people's minds with some of this information.

Let's talk for a few more minutes about other things that can impact indigenous, so to speak, or native populations that are not related to stocking.

Are there any other things like land use or water quality and things like that that can seriously impair those species or the health of those species?

- Yeah, one of the biggest problems right now is when populations such as the brook trout decline, they wanna blame it on climate change and they ignore things like deforestation by removing the riparian habitat in the shade over streams.

By building huge parking lots, the rain water hits those parking lots, sheets off, then runs into the stream and heats the water in the stream.

You also have different types of domestic sewage and problems that are impacting the brook trout streams and declining the population.

So when you look at declining populations of brook trout, you need to look at a holistic approach and look at all the things that may impact the stream and the populations of fish that live in the stream rather than blaming it on just one thing such as climate change and ignore the other adverse effects that may be occurring in the system.

- Well, thank you very much, Jay, for joining me today.

And thank you, folks, for listening.

- It was a pleasure to be here. Thank you.

(water susurrating)