National Geographic : 1996 Apr
Trashing a Trout Stream Touchstones of wildness, trout are barometers of stream health. Where they thrive, the water runs clean, cold, and oxygen rich. Impinge on its purity, and they-and the stream life that sustains them-will be the first to register ill effects. The imaginarystream snaking across these pages runs a gantletof human abuses that have renderedmany real-life streams unfit for trout. "Most of the trout's woes stem from our misuse of land," asserts Pete Rafle of Trout Unlimited, a conservationgroup. "To save a trout stream, you have to protect its watershed." Mining Like open sores, old mines ooze acid and heavy metals lethal to trout. Cyanideused to extract gold enters streams when settlingponds leak. Logging Treeless banks bleed silt that suffocates trout eggs and insect larvae. Loss of shade warms water.