Hello this is Dr. Tom Mullikin with SCDNR for Into the Wild.
In a small mountain stream, a native brook trout may be only a few inches long. But that fish is living near the southern edge of a cold-water world.
Brook trout need clear, well-oxygenated water that stays cool through the year. In South Carolina, suitable streams are generally limited to higher elevations in Greenville, Pickens, and Oconee counties. Shade from streamside forests helps hold temperatures down, while clean gravel and flowing water support spawning and aquatic insects.
Warm water holds less oxygen, so even a small temperature change can matter. Protecting a brook trout stream means protecting more than the channel itself. It means protecting the trees, springs, slopes, and rainfall that keep cold water moving downhill.