In the 1950s, an era when there was little attention to science in the NPS, Great Smoky Mountains National Park in Tennessee and North Carolina was the site of a misplaced effort to improve recreational fishing by removing native nongame fish from a park stream. Because knowledge of the park's fish populations was limited, several species of fish previously unknown in the park were both discovered and extirpated during that operation. For many years it appeared that one species—the Smoky madtom—was both discovered and made extinct by that management action; this fish has subsequently been found outside the park, and a reintroduction trial is now under way.
Similar problems were caused by the introduction of New England brook trout, which has come to predominate over the native southern Appalachian brook trout. Research now indicates that the native trout is a genetically distinct subspecies, and its gene pool has been contaminated by the release of the exotic trout. Now only a few streams in the park