In late April, two Paiute brothers scaled chalky cliffs on their reservation that overlook the Truckee River and discovered giant trout nests, called redds, the size of backyard wading pools, which 25-pound fish had dug in the river’s pebbled bottom using their powerful tails.

Once the discovery was reported, U.S. Fish and Wildlife and tribal fisheries biologists swooped in to find nearly 180 such redds. They also confirmed the existence of the first native baby Lahontan cutthroat trout born in this river since before World War II. News of their spawning pushed the trout into the news, as tribe members, conservationists and anglers celebrated the species’ resilience.

“To know that this fish is spawning naturally again is epic,” said Doug Ouellette, who has fished Pyramid Lake for 40 years. “Against all odds, this trout is a survivor.”

Cutthroat trout, named for the streaks of crimson underneath their jaws, colonized the cold mountain rivers and lakes of western North America some 4 million years ago, evolving into a dozen different subspecies. The Lahontan subspecies is the biggest, and the strain with the largest fish comes from Pyramid Lake — the end point for snowmelt from the Sierra Nevada that pools in Lake Tahoe and then cascades down the 120-mile Truckee River into the desert of the Great Basin. Until the last ice age ended around 12,000 years ago, much of the Great Basin was flooded under an inland sea called Lake Lahontan. In its waters swam giant minnows and suckerfish called Cui-ui. To eat these fish, Lahontan cutthroat trout grew exceptionally large while still very young.