Your best place to make a trout withdrawl: near bankside structure.
Many of our area rivers are priming for the salmonfly hatch—many river's largest aquatic insect and a trout’s time to gorge themselves post-runoff. The salmonfly, aka Pteronarcys californica for those with overly-refined palletes or those who fancy in the ignorance of others, is a giant bug on the minds of any Montana fly fisher for the next several weeks. Their emergence, or hatch, will occur in earnest very soon. Because these insects hatch near bank-side structure, it is imperative to fish near the banks. This doesn’t necessarily mean you have to change your game entirely, just a few tweaks here and there.
Start with your casting. I can cast a 100 feet. Do I need to?
As a young angler I was obsessed with casting 100 feet of fly line. My brother Carl was a born distance-caster and his fly would always land a leader’s length beyond mine. So I learned to study the water closer to where I stood, and quickly found that there was always prudent water to ply within fifty 40 feet or less of where I waded. As a guide, it’s always nice to have a “hucker” in the boat, someone who can really “air it out,” but the folks who catch the most fish cast fifty 40 to sixty 50 feet with accuracy and manage their line diligently. Whether guiding or fishing on my own, I’ll take an absolutely precise 40-foot cast over an “in-the-ballpark” hundred-foot cast any day.
Join the buffet line. Follow the food source and your find more fish.
During morning hours, trout will be congregated underneath overhanging willows and near bankside structure to catch the migration of stonefly nymphs, which make their way from mid-stream boulder to bank in order to climb ashore and hatch. Later in the day, trout will seek out eddies where the dead or crippled bugs are still swirling around, and have not yet been washed downstream. The old saying, “Fish where the fish are” should be modified: “Fish where the food is, and the fish will be there.”
Go big or go home (or to your local fly shop). Increase your tippet strength and your fly size.
Trout hang out along the banks because the food is there. They also take refuge in the cover along the banks. Cover provides safety from predators and offers a break in the post-runoff currents. Although ideal for trout, rocks, trees, and other fly-snagging nastiness translate into snags and lost flies. You’re going to lose a few flies. That is a given. However, fish a heavier pound test tippet and you might loose less. I rarely fish anything lighter than 2X while pre-hatch nymph fishing. I also ensure my knots are properly tied and my tippet is not old—now might be a good time to restock your tippet selection as the stuff does detoriate with age.
As for fly selection, bump up a size or two from what you think is large enough. Salmon and stonefly nymphs are large and in the fast water of the Gallatin you’ll need a fly that sparks a trout’s interest. Hook sizes 2, 4, and 6 are common sellers this time of year. When you snag a stick, a larger hook tied on a stout tippet stands a better chance of dislodging the stick then breaking-off. And…when catch that pig brown trout the larger hook might mean you land in the heavy currents of run-off.
The next few weeks serve up some of the season’s most exhilarating fishing—rivers are in post-runoff and hatches of are large insects are the norm. Your fishing mindset doesn’t need a total overhaul, just a slight tune-up.