Brook trout mirror region’s fall foliage

Every autumn, our hills display a signature that only a few regions can claim. The blazing tint of maple, gum, and hickory leaves, blended with somber oaks, presents a backdrop so familiar here that we forget, or overlook, its splendor. Though we don’t always devote attention to fall foliage, we expect it. It’s part of our place on the Earth.
But as the woods blaze around us, another lesser known aspect of local nature transforms itself in a similar way, rivalling even the maple’s riotous hue. Believe it or not, it’s a fish.
The brook trout, our official state fish and the only trout native east of the Mississippi River, spawns in the fall. When that crucial season arrives, males display flaming flanks of orange, yellow and red, speckled with neon blue and scarlet, to impress the females. The females turn a deeper color too, but less flamboyant than their suitors. When I am privileged to see a spawning male brookie in autumn, its brilliant colors, accented by snow-white edges to the fins, strike me as a wonder you’d expect to see on a TV special about some exotic place, rather than our local mountains. But they’re here, living on the edge of survival.
Brook trout require the cleanest and coldest of waters. Nowadays we’ve confined them to the highest tiny tributaries that blend to form our larger streams. Most fish spawn in spring, but brook trout spawn in fall so the eggs can hatch during winter when the water is cold. Young brook trout, called fry, are highly vulnerable to warm temperatures. Hatching during winter allows them to gain some strength before water temperatures reach threatening levels in summer and early fall. Brook trout fry begin to succumb when water temperatures exceed 68 degrees. Adults can tolerate up to 77 degrees for short periods. Conditions like we’ve had over the last six weeks–hot and dry–are tough on brook trout. As stream flows shrink, they seek out whatever shaded pools remain. Already stressed by temperature, they can be easy prey for otters, water snakes, raccoons or even bears.
And brook trout face new threats. Scientists from California University of Pennsylvania have documented that, due to warming climate, brook trout streams on Laurel Ridge peak at higher summer temperatures than just 30 years ago. Meanwhile, the decline of hemlock trees, attacked by the invasive hemlock woolly adelgid insect, reduces the shade that cools our creeks in summer.
But if brook trout live a risky live, they are also resilient. They’ve been spawning in our mountains at least since the last glaciers (which did not reach quite this far south) retreated northward 11,000 years ago.
It’s ironic that wild brook trout–relatively rare here in their native range–can become a pest in other places. Before fisheries managers understood the importance of keeping native fish in their native haunts, brook trout were stocked all over the Rocky Mountains, right into streams where native cutthroat trout already thrived.
There, brook trout spawned with amazing success, sometimes competing the original fish out of their habitats. Most fisheries agencies in the West now advise anglers against catch-and-release with brook trout. Their informed appeal today is to remove every brook trout you catch.
That’s not a valid approach here in the East. Few pursuits are more enjoyable than fishing for wild brook trout on remote mountain streams, but brook trout are under so many stressors that it’s best to release them all unharmed.
There’s even a controversy among anglers and fisheries experts about fishing for brook trout during the fall spawn. Some maintain that the threats of warming waters, flood and drought are so overwhelming that the impact of recreational fishing is slight. Others prefer to give brook trout a break during the spawning season, not wishing to add any unnecessary degree of risk.
Personally, I mostly stay out of the streams when brook trout spawn, but it’s hard to resist a little occasional and careful angling, just to admire the brook trout’s fall colors.
That’s what happened one exquisite October day more than 30 years ago. Our first child, our daughter Colleen, was born before dawn. We lived near Harrisburg then, and I’d already taken the day off work for paternity. But it was still early, and the mother and baby needed rest. So, I headed into the long parallel ridges north of the city, where trout streams gather and flow west toward the Susquehanna. I didn’t know then about the fall fishing debate; and anyway, I felt like celebrating. I caught four brook trout with flaming red bellies, released them, then returned to the truck for my double-barrel Fox and shot a ruffed grouse flushed from mountain laurel along the creek bank. Four trout, a grouse, and a baby girl. That was one fall day to remember.
Ben Moyer is a member of the Pennsylvania Outdoor Writers Association and the Outdoor Writers Association of America.