The Bighorn River flows out of the Yellowtail Dam near Fort Smith, Montana, a cold, clear ribbon of water cutting through the arid, sagebrush plains of the Crow Indian Reservation. It is an improbable river, an oasis of trout in a landscape that looks like it should belong to rattlesnakes and pronghorn antelope.
But the Bighorn is, without question, one of the most productive trout fisheries in the world. The cold water from the bottom of Bighorn Lake creates a stable, nutrient-rich environment, and the trout grow fast and heavy. It is a tailwater, like the Missouri, but it has its own distinct character, its own rhythms, and its own demands.
To fish the Bighorn is to fish the nymph. While there are times when the dry-fly fishing can be excellent, the vast majority of the trout in this river are caught below the surface. A man must learn to read the water, to understand the subtle currents and the depth of the runs, and to drift his nymphs with absolute precision.
The Nymphing Game
The Bighorn is a river of seams and drop-offs. The trout hold in the transitional water, where the fast current meets the slow, waiting for the conveyor belt of food to bring them a meal. You must fish two flies, usually a larger scud or sowbug pattern followed by a small midge or Baetis nymph, and you must fish them at exactly the right depth.
It is a game of strike indicators and split shot. You watch the indicator as it drifts down the seam, waiting for the slightest hesitation, the smallest dip. When it happens, you set the hook quickly and firmly. The trout here are strong, and they will use the heavy current to fight you, making long, determined runs.
There is a rhythm to nymphing the Bighorn. Cast, mend, drift, watch, strike. It requires focus and discipline. You cannot let your mind wander, or you will miss the take.
The Hatches
While nymphing is the bread and butter of the Bighorn, the river does offer spectacular dry-fly fishing at certain times of the year. The midges hatch year-round, providing action even in the dead of winter. But the true dry-fly season begins in the spring, with the arrival of the Blue-Winged Olives.
The BWO hatches on the Bighorn can be prolific, blanketing the water on overcast days. The trout move into the shallow riffles and the slow back eddies, sipping the small mayflies with a quiet rhythm. In the summer, the Pale Morning Duns and the Caddis take over, followed by the Tricos in August.
But perhaps the most famous hatch on the Bighorn is the Black Caddis hatch in the late summer. The trout key in on the emerging pupae, slashing at the flies just below the surface. It is fast, exciting fishing, a welcome break from the deliberate pace of nymphing.
The Bighorn is a river of abundance, but it is not a river that gives up its fish easily. The trout are educated, the currents are complex, and the pressure from other anglers can be heavy. But for a man who is willing to learn the water, to master the nymphing game, and to appreciate the stark beauty of the plains, the Bighorn offers a kind of fishing that is hard to find anywhere else in the world.
Open-source photograph