Lake Crescent is home to two trout found essentially nowhere else: the Beardslee and the Crescenti, distinct forms of rainbow and cutthroat trout that evolved in isolation after a landslide cut the lake off from the sea thousands of years ago. The large, silvery Beardslee trout feeds in the lake's deep open water, a notable example of localized evolution.
Down in that cold clear water swims a fish you'll find almost nowhere else. When the landslide sealed this lake off from the sea long ago, the trout trapped inside were cut off to evolve on their own, and they became their own peculiar kinds, the Beardslee and the Crescenti trout, found only in this one lake. The Beardslee grew big and silvery, hunting out in the deep open water. They're a living example of what isolation does, the same trick that made this whole peninsula a breeding ground for one-of-a-kind creatures, played out in a single lake.
Photo: USFWS Mountain-Prairie · Public domain
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