Finding unique angles, lighting and intricacies in the development of salmonflies with my Nikon D5 and 105mm macro lens is not only rewarding for sharing rarely seen images, but it is also helpful when climbing behind the vise to match fly patterns for all phases of their transition to adulthood.

Salmonflies: Winged Buffalo Migration

Standing atop Idaho’s lodgepole forest-clad Box Canyon, my high school fishing buddy and I watched hundreds of salmonflies clumsily crisscrossing the sky above the Henry’s Fork. We had just had our butts handed to us all morning. We were unable to hook a single trout over fifteen inches. While stowing our gear, a dust laden Bronco pulled down the Targhee Forest service road and parked alongside our underclassed VW beetle. We greeted the angler as he exited his truck and pulled on his Seal Dry latex waders and prepped his flyrod. He introduced himself as Will Godfrey, a local Island Park fly shop owner. 

We opted to watch our new, self-assured, angler acquaintance from the comfort of the basalt cliff. Fully expecting to revel in some ‘hot shot’ angler’s misfortune to validate our own poor showing as simply a tough day. It was immediate and it was mesmerizing. He laid out an aggressive, long tight loop against the heavy seams of each midstream broken boulder, each the size of our car, tipped with a single, bulky Sofa Pillow dry. By his third boulder he went tight on a five-pound rainbow, porposing upstream in a rhythmic series of violent leaps and crashes before succumbing to Godfrey’s side pressure and subsequent release.

Eastern Idaho fly shop advertises the magic cross over of both large pteronarcys salmonflies in the high reaches of the river and golden stoneflies coming off on the lower river. While these stoneflies’ appearance is similar, their omnivor versus carnivor diet and feeding acitvity are vastly different. For the greatest chance at success, anglers should imitate each stonefly accordingly. (For the record, the fly shop wasn’t open.)
Covid did nothing to lessen the onslaught of anglers chasing salmonflies on the Henry’s Fork of the Snake in 2020. Both out-of-work guides and regional anglers expecting pandemic solace with the big bugs were surprised to find mega throngs of anglers. More of the same is likely coming this spring. Stay patient, respect all wading and boating anglers and you might even consider finding lesser known waterways.
Early spring fishing with salmonflies on the Henry’s Fork enjoins all of the senses. This image displays the common, light spring rainfall found along the lower caldera rim. Here, alder and willow-lined banks are joined by blooming hillsides of yellow balsam root flowers, accentuated with the aroma of fresh sage, bitterbrush and Indian paintbrush.

That was forty years ago. We were two out-of-state teenagers stunned, and schooled, unknowingly by one of the great Rocky Mountain anglers of our youth. But even more consequential, we witnessed the magic of the famed salmonfly hatch in the otherworldly setting of the Henry’s Fork. It was my personal baptism into the giant salmonfly world of Pteronarcys Califronica. This prehistoric and annual migration has since shaped vacations, retirement dates and family relationships.

It has become the ember of countless western river pilgrimages to photograph the modern-day, aquatic insect equivalent, of the great plains migrations of bison in the 1800’s. The similarity with bison migrations of yesteryear doesn’t end with the vast swarms of bugs that fill the sky each spring. Salmonflies, as were bison, are one of the seminal health indicators in our western ecosystems. Stoneflies can only thrive in pure, clear, flowing rivers and streams.

Pteronarcys californica stonefly nymphs migrate to the river’s edge in some cases weeks prior to their actual emergence. The lifecycle of these largest stonefly species is typically three years with age class cohorts occuring each year. So seeing these adult nymphs all being the 2″+ jumbo size on a single boulder shows that staging for immenant emergence is real. No better news exists.
Emerging stoneflies have always reminded me of heavily armor clad, midieval knights or Lord of the Rings creatures. But look closely and you will discover fine, symetrical patterns up and down the thorax pads. While average anglers focus on the winged adults, for good reason, the best action can be miles ahead as restless nymphs wrecklessly migrate on the river bottom and large trout gorge aggressively.
I never tire of discovering the intimate and largly unseen natural artistry of hatching salmonflies and other aquatic insects. These large stoneflies are constantly changing form. Including evolving wing color. When newly hatched, wings are a milky opaque mishmash which evolves into a beautiful quad translucent, and heavily veined, wing in mature adults.
After a decade of photographing salmonflies, I became enamered with the intricate detail and beauty of these aquatic insects. Subsequently taking thousands of images. Here a newly hatched salmonfly slowly unfolds his wings as they fill with hemolymph blood, allowing them to form and dry in order to join the streamside orgy fully equiped.
Stonefly commitment doesn’t get more real than wearing it permanently on your flesh. Cory Fleming’s stonefly tat took center stage on his forearm as he stepped into this Madison river tributary inside Yellowstone National Park.
A light spring drizzle couldn’t obscure Henry’s Fork rainbows hunting down struggling, egg laying salmonflies along grassy river banks. Wedging myself amongst basalt boulders, and armed with my Nikon 70-200mm lens, I had most everything needed to get the rare image of a feeding trout on the big bug. (Okay, reality is that it also took four years of effort until mission accomplished.)
Prowing the edgewater, angler Kelli Dotson taps a deep Henry’s Fork rainbow that was looking for fluttering adults with Lawson’s Henry’s Fork Foam Salmonfly pattern.
Both the upstream progress of the salmonfly hatch and the egg laying females above the river are hindered by spring days that turn wet and cold. So taking time to dig thru cattails and streamside grass can quickly determine if flying swarms are yet to come or if the emergence is long since moved on.
Georgian native and eastern Idaho transplant, Ben Ortman, releases a salmonfly gorging cutthroat while wading the upper reaches of the Yellowstone River on opening day in the national park of the same name.
Releasing a gnarly snouted brown trout is the ultimate reward for deftly fishing a dry salmonfly pattern along ambush rock structures on Idaho’s Fall River.

An entire age class of salmonflies, or generations for that matter, can simply disappear due to a single, tragic sediment event. Or they can weaken from a perpetual warming stream flow aided by reckless degradation of riparian habitat or careless toxic releases into our tributaries. Our individual and collective efforts, aided by the support of noble frontline, science-based conservation organizations like the Henry’s Fork Foundation and Trout Unlimited, can continue to enhance, protect and preserve our waterways to the benefit of anglers and mankind. But also ensuring that the otherworldly, annual salmonfly migrations of the American West live on forever.

– Robert Dotson

Salmonflies are most active during (and between) dusk and dawn when it comes to their emergence from the river depths. But it is hard for the dry fly angler to beat a warm spring day fading into evening, with an ever so slight breeze to get trout actively looking up. These are the times that drive me to search for the largest fish in the river. Trout that only show themselves when their major food source is available during daylight hours.

Most structures along the length of the Henry’s Fork give the ghostly emerging stoneflies the friction and texture needed to escape their exoskeletons. Henrys Fork Foundation director Brandon Hoffner takes a midday break amidst the invading army of stonelfies scaling an eastern Idaho bridge abutment.

Salmonflies, as were bison, are one of the seminal health indicators in our western ecosystems.

Contributed By

Robert Dotson

Robert Dotson left the Seattle tech world ten years ago and was reunited with his Scott rod, Nikon and a Pelican case. Together with his wife Kelli, they hunt the kiwi backcountry, ocean flats and remote river bottoms. But always return to their first love – the back roads of the Rocky Mountains. His art is frequently found in fly shops, lodges and conservation fundraisers with work appearing in The FlyFish Journal, The Drake, FlyLife, Tail, Jackson Hole Mag and his earliest work in…Catch Magazine.  

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