When Christopher Michael talks about the Rio Grande, it's easy to see it the way he sees it—which is magical. The sun is high enough over the canyon walls to have started to bake, even on this late March day, and he's set his fishing rod aside for a few minutes. The runoff is high and the fish disinterested. But when he talks about the river, he paints it in all the seasons and shades he's seen it.

It's easy to imagine it glowing blue at dusk with caddis flies skidding across its surface, or dappled golden at dawn, or running darkly through a snow-covered desert. And it's easy to imagine him casting his line over the water, his fly targeted for the deepest thread of current or the still pocket of an eddy, waiting for that moment he says matters most: Not when the fish closes its mouth around the fly, but the moment it looks up and recognizes there's a human on the end of the line. That, he says, is when the real fight begins.

Michael grew up around the Taos Pueblo and his grandfather taught him to fish when he was the youngest of the cousins and dropped off the back of the pack.

"He taught me one simple knot, a little twist knot, and away we went," Michael recalls.

After high school, he moved to Arizona. He had a job and a wife, but he missed the Rio Grande, so he came back.

"It's a gem," he says. "It's like the Grand Canyon—there's only one."

He can get from his house in Questa to the river in half an hour, and he's there four or five days a week. Even when it's muddy. Even when it's snowing. Even when that means walking out the back door as his wife walks in the front, handing care of their two kids over to her. Even when his friends are late or flake entirely. Even after dark, when the river is moonlit and the 2-foot-long brown trout more likely to bite.

"Most of the time, I'm fishing by myself," he says. "I'm down here and the lightning bugs are firing off over the water—and it's such a waste that I'm the only one."

Michael was out for the Questa Cutthroat Festival, a gathering of fish aficionados where volunteers can hike down the steep trails of the Rio Grande Del Norte National Monument carrying bags filled with native cutthroat trout fingerlings. The New Mexico Game and Fish Department supplies the trout as part of an effort to restore the state fish to more of its traditional waterways. The trout is a brilliantly patterned fish, golden with brown speckles and a red cheek.

A handful of volunteers also carry a fishing rod down, as Michael does, and he casts into an eddy in hopes of clearing out the bigger fish to make space for the newcomers. The Rio Grande cutthroat trout has seen its habitat depleted by wildfires and drought and crowded by nonnative fish. Its numbers have plummeted, and the state reports it occupies just 12% of its historic range.

"This is their home, and it's kind of our fault they're not here," Michael says. So if he reels in an invasive species, pike, or a brown or a brook trout, he doesn't put it back. The hope is to make a little more room and leave a little more food for the native species. After years, he says, he thinks he sees that gesture making a difference in the river.

Michael is just a few years into running a guiding outfit, Rio Grande Del Norte Outfitters, bringing people here and into other lakes and streams around Northern New Mexico. It's not the pleasure cruise some guided tours can be. He'll pack a lunch for guests, but they have to handle the hike for themselves. He's not shy about that and what they're really after.

"We're chasing trophies," he declares. "It's cool to catch fish, but we're chasing monsters."

He's aiming for state records this year.

That he knows where to look for those fish, and how to draw them in even when they're reluctant, is part of what his many days on the river have taught him. Still, he says, every time he goes, he learns something. At other fishing spots, he'd go "pound it," but to him, the Rio Grande is sacred.

"This place—you'll never forget this place," he says. "Here, we can be a part of the last frontier."