What's Up, Watershed? Cool Waters: How Trees Help To Protect Pennsylvania’s State Fish

One of my favorite things to do in the summer is to swim in streams.  For me, the refreshing feeling of jumping into a cool, clear forest stream is far better than the sterility of a chlorine-filled pool.  During my stream swimming adventures, I’ve often been amazed at how cold the water can stay even in the middle of summer. Recently, I learned that Pennsylvania’s state fish — the brook trout — actually requires these colder creek temperatures to survive.

In this edition of What’s Up Watershed, we’ll learn about these cold-water chums and what they can tell us about the health of our streams.  Read on!

Chris Bunn

Environmental Program Coordinator

Pennsylvania Resources Council

Brook trout is a beautiful fish species that calls our mountain creeks and streams home. It is the only native trout species in Pennsylvania and prefers water temperatures of about 59 degrees, which is pretty cold if you ask me!

Brook trout’s beauty is a striking display of design and color: a dark green underhue, circular red and brown speckles, and squiggly cedar-colored lines that trace over their backs.  Until the late 1800s, these fish lived abundantly in the majority of our state’s creeks and streams.  In recent years however, their population has been severely reduced and has even disappeared from many parts of their historic range.  But why?  

Being a water-rich state, Pennsylvania features more than 86,000 miles of streams and rivers!  

In the few hundred years since Pennsylvania was colonized by Europeans, the land adjacent to these streams has become increasingly impacted and changed by human development.  This development has often involved stripping the land near streams of native vegetation. 

This vegetation, which includes trees, shrubs, and herbaceous plants, is called a riparian buffer.  These areas play a vital role in keeping our streams clean, cool, and habitable for wildlife.  By depleting and destroying these areas, we have also depleted and destroyed habitat for wildlife like the brook trout.   

If you’ve ever been in a city on a hot summer day, you’ll know how much cooler it feels underneath the shade of a tree canopy.  Trees alongside streams have the same effect — they cool down the water temperature, providing wildlife such as brook trout with ideal habitat and protection from predators. 

Streamside trees also drop their leaves into the water, providing an important source of food for macroinvertebrate organisms!  These organisms are, in turn, an important source of food for brook trout. 

Riparian buffers provide many other benefits, and without them, streams quickly become too warm and polluted for brook trout to survive. If you live along a stream, lake, or river, installing a riparian buffer can help you to protect our water and your property.  For step-by-step guidance on how to install a riparian buffer in your own backyard, visit this guide. 

You don’t need to do it alone either — our state’s Department of Conservation and Natural Resources actually provides support to landowners who wish to install their own buffers.  Even if you don’t have a streamside property, you can help support riparian buffer installation by working with an organization such as Penn State Extension. 

---

If we all work together, we can make the world safer for not only brook trout but also for our future generations. 

Take care and see you next time on “What’s Up, Watershed?”! 

Photos shown above (top to bottom):  brook trout (courtesy of USNFWS); Beaver Run eroded streambank before habitat restoration; Black Forest Stream