This journey of trying to locate large wild native brook trout in Pennsylvania and the surrounding states has taken me to some interesting places. None more unusual than one I visited recently. This one makes me rethink things on a lot of levels and from a lot of perspectives.
One of the often-cited traits of brook trout is that they require pristine clean water to survive. While this is certainly true, I’m finding more and more cases where they may be better suited than other species to survive in water that is less than pristine from a chemistry standpoint. I’ve been volunteering with an association in central PA to clean up a large watershed that is heavily impaired from AMD (Abandoned Mine Drainage).
A few weeks ago we identified an undocumented population of brook trout in one of the tributaries there. Our goal was to sample the water quality in the field and collect samples to be sent to a lab for verification. The field sampling was telling as we encountered water with a relatively low pH and high Conductivity (high conductivity is a sign of dissolved metals like iron, aluminum, and manganese suspended in the water which is toxic to fish). Despite the low pH, we found wild brook trout in a slightly better section of one of the tributaries.
One common feature of these AMD waters is that because the water is coming out of underground mines, the temperature is cooler than surface runoff water. Especially in lower elevations or in urban areas. These AMD waters can be thermal refuges as long as the pollution isn’t too bad.
I explored an AMD impaired water today for the first time and ended up catching several large brook trout. This particular stream is unique in that the pH is well within the tolerable range for brook trout, and the conductivity is likely fairly low as well. I need to take my testing kit there to verify the parameters, but the stream is absolutely full of brook trout. Some large ones too.
Thankfully, this stream really hasn’t been “discovered” yet as I believe the locals all think it’s heavily polluted and contains no fish. It also has some really nasty waste discharges dumping into it. The authorities are aware and the discharges are within the law. It’s still nasty stuff though. The side effect of the pollution and obvious waste in the stream is that I suspect no anglers have any interest in consuming any fish from the stream even if they knew they were there.
Because of it’s situation, there are no brown trout in the stream. Brown trout are less tolerant of lower pH than Brook Trout are. This makes AMD impaired waters a unique opportunity for brook trout to thrive without the negative impacts from surviving in a sympatric population of brook and brown trout. I believe this is why the brook trout here grow so large. They have no competition.
The photos of this stream that I’m sharing really don’t tell the story of this unique place. Despite the photos depicting a green lush forest setting, this stream is urban. There is industry, roads, and houses all along it. The stream is littered with runoff waste from the nearby residences. I found several bicycles in the stream, a lot of industrial waste like cables, wires, steel beams, and other trash throughout the stream.
Given the urban nature of the stream, I’m reluctant to share any photos that might give away it’s location. I saw no signs that anyone ever fishes this stream and again, the public’s perception of the stream is that its polluted and has no life. Even if someone were to catch a trout from this stream, you would really have to question whether it would be wise to consume it.
I like exploring streams whether they’re miles into the back country or running through a shopping mall. Each has it’s own unique experience and feeling that comes with venturing into less traveled areas. Given the fish I saw and spooked today, I’ll certainly revisit this gem of a place.
As I run into fish like this in a place like that, I can’t help but wonder whether some things are best left alone. The pollution that still occurs here can’t be good for the environment, and it’s counter to every fiber of my being to support waste discharge into streams, but there’s clearly something working here. The absence of competitive nonnative species, the size of the brook trout, the macro life, the year-round constant cold temperature, and the unappealing nature of the place make it a brook trout refuge in a highly unusual place.