Fishing the Salmonfly Emergence on the Yellowstone River!

Every great trout water has three “signature hatches,” I’d argue. Applied to the Yellowstone River, you’ve got the Mother’s Day Caddis, swarming over the river prior to runoff and the ‘hopper “hatch” in mid- to late-summer, as the Montana breezes blow chunky terrestrials into the trout’s domain. And then there’s the salmonfly hatch in late June to early July. Here on the ‘Stone we have a love-hate relationship with the giant stoneflies, the largest aquatic insects in the river. There’s always the threat that runoff will still have the river too high and muddy for the fish to see the bugs, as big as they are. Or the fish will be so gorged on nymphs to bother with the fluttering  adults passing overhead. But if the stars align, the dry fly fishing can be epic. Giant meals floating right along the bank can entice even the river’s largest denizens to the surface.

But an emergence, a “hatch,” is always more than the endpoint of bugs floating downriver. Regarding salmonflies, the nymphs are a big deal, figuratively and literally. They’re huge! Three years of growth in the river results in a bug the size of your thumb, a 16 ounce steak for a hungry trout. What’s more, the big nymphs crawl to shore and emerge on bankside willows and rocks, making them particularly vulnerable to waiting fish. Fish a big dark stonefly nymph tight to the bank and willows (if you’re not losing flies, you’re not casting close enough), just before the true emergence gets going, and you might have the best day of fishing ever. Timing it right can be as much intuition as science.

But we’re really in it for big trout smashing big dries, right? Better consult a psychic! Hi You’re usually going to have the best fishing at the “leading edge” of the hatch. It doesn’t take long for the fish to engorge themselves, and the hatch tends to move upstream a few miles a day. So check the reports of where the bugs were popping today and plan to fish the upstream stretch tomorrow. Or take a look at the willows and rocks in the morning with an eye for resting adults or fresh-looking nymphal shucks. Salmonflies are not early risers, and will usually begin emerging mid-day, though bugs that hatched a couple of days ago might still be hitting the water earlier. And don’t be afraid of fishing “below” the main hatch. The trout won’t be as stuffed and they’ll still come up for the dry, even if there aren’t still insects actively emerging.

As far as fly patterns, stop by Sweetwater Fly Shop and we’ll point you towards some of our favorites. Wherever you’re getting your flies, take a cue from the salmonfly itself, which is primarily black with orange “highlights.” Many commercial patterns emphasize the orange, but I prefer flies that are mostly dark, with smaller bands of orange. Just buy plenty. Lose some flies to the willows or you may as well be on a splash and goggle float!

If you hit it right, you might have an epic day on the ‘Stone! If you don’t hit it right, you still might have an epic day on the river. You won’t know unless you try!