The brown trout here were planted in the 1930s. By freak of nature, the species has evolved into two varieties that determine their life course at the smolt stage -- those that remain in the river as resident fish, which remain small, and yellowish in hue, just like the brown trout in Europe, New Zealand, and North America, and the silvery sea-runs. You can tell whether a sea-run trout is "fresh" from the ocean by its color. The "fresh" fish are bright silver.