Big water, big bugs, and big fish. The salmonfly hatch is everything a fly fishermen dreams of.
The salmonfly hatch is one of the most fascinating hatches in the Greater Yellowstone Region. It can be an angler’s most anticipated or dreaded hatch of the year. Whatever your opinion on the salmonfly hatch, one can’t discount its importance as a food source for trout. Anglers who understand the hatch and how to fish it have the chance to catch the biggest fish of the year on a dry fly.
Like many anglers, I’ve spent my fair share of the summers chasing the epic salmonfly hatch with varied success. I love tying flies to imitate the bug as much as I enjoy fishing the hatch. The thought of a big brown rising from an undercut bank to eat my foam fly stays with me all winter. While I still have much to learn about the salmonfly hatch, I share my insights and tips for the DIY angler based on years of chasing the hatch across the West.
What Is The Salmonfly Hatch and Why Is It Important?
The salmonfly, pteronarcys californica (if you’re into scientific names), can be found on many rivers throughout the West and is the largest stonefly in the region. Its orange hues and immense size make it hard to miss when on the river.
In the Greater Yellowstone Region, many blue ribbon streams host a population of salmonflies. Rivers like the Madison, Big Hole, Yellowstone, and South Fork of the Snake River are home to famous salmonfly hatches. However, many rivers and creeks in the region hold populations and fish well during the hatch.
An angler can start chasing the hatch in the middle of May and continue through July by bouncing around rivers. The hatch moves up a river, starting at the bottom and moving as water temperatures warm up the watershed. Timing the hatch may be the most challenging aspect of the hatch with variable weather and it coinciding with runoff.
While many anglers look forward to the hatch, it can make for challenging fishing. With so much protein between nymphs and adults, trout get full and sustain from eating for days after the initial hatch. Any western trout angler you talk to has stories of poor fishing while many salmonflies flutter on the banks.
The size of these insects consistently surprises me. Every winter, I tie up a few flies to imitate the bug. I fear my flies will be too big when tying them, but realize how small my flies are when a real salmonfly about knocks me out as it flies across the river. When people suggest hook size two and four dry flies, they are not lying.
The salmonfly is important because of its size and availability as a food source for trout. Stonefly nymphs live in the river for three to four years before they grow large and hatch into adults. With multiple age classes, some years can be better than others for the salmonfly hatch. Trout feed on these insects year-round and they account for the majority of the trout’s weight during the spring and summer months. I have heard estimates stating that 50% or more of a trout’s nutrient intake in a year occurs during the salmonfly hatch. This is why every angler should get to know this hatch and how to fish it.
Here, I share a few insights for the DIY angler to consider when chasing the salmonfly hatch in the Yellowstone region.
Lower Your Expectations
The problem with the salmonfly hatch is the high expectations many anglers go into it with. This expectation is the killer of a good day of salmonfly fishing.
Many fly fishermen expect to catch fish using dry flies on every cast tight to the bank. This may happen a few days a year (and it’s as epic as you could imagine), but most days disappoint. Instead, you often find a crowded river with anglers casting to trout full of bugs and not feeding. This makes for many average to poor days of fishing during the salmonfly hatch.
After being humbled many times during the salmonfly hatch, I go into the hatch with a different mindset than I used to.
One good fish on the salmonfly dry fly each season.
That’s all I hope for. I define one good salmonfly fish for myself as a fat, 17+ inch trout (though I hesitate to put numbers to it). I am more than satisfied if one fish of some quality comes up and eats my big foam fly a season. If more anglers had this mindset, or lower expectations in general, the salmonfly hatch would be more enjoyable for everybody.
Watch Water Temperatures and Weather Patterns
Water temperatures are the first sign a hatch may begin for all regional hatches. The water temperature I look for when chasing the salmonfly hatch is 55 degrees. If the river reaches this temperature a few days in a row, I expect some salmonflies to be fluttering around.
Another consideration for the fly fishermen is the weather pattern leading into the hatch. Adult salmonflies are most active in warm, sunny weather. Cool, cloudy weather days tend to be tough for salmonfly fishing. Look for a few days of warm weather coming off a cold trend to be the most productive. Watch this Orvis video for a detailed description of predicting a stonefly hatch.
Fish The Nymph
We all want to catch a big fish on a big dry fly. While this is possible during the salmonfly hatch, the salmonfly nymph accounts for more big fish every year. The stonefly nymphs make their way to the banks as water temperatures warm. Trout key into this migration and feed heavily on these insects as they move into shallow water.
Fishing big stonefly nymphs in shallow water (3 feet or less) in the weeks preceding the adult hatching makes for better, more consistent fishing. An oversized pats rubberlegs 18 inches below your dry fly is a perfect setup to fish the nymph’s migration.
Commit To The Big Bug
Unless you time the hatch perfectly, only a few fish will be willing to eat an adult salmonfly each day. Though fishing the salmonfly nymph may be more productive, we all want to see the mouth of a big brown inhale our foam fly.
For this dream to come true, you must commit to the big bug and hunt it in every likely spot along the bank. I fish salmonfly dries with the same mindset many streamer anglers have, committing to the fly and hunting for a willing fish. You may float the fly through lots of juicy water (and over many fish) before finding the fish willing to come to the surface and eat.
Fish the big bug hard, tight to the bank, all day long. You may be rewarded with the big fish of the summer.
Fish At Night
Many salmonflies crawl to the banks and molt into their winged form during the evening and night hours. I witnessed this on the Gallatin River last summer, with many bugs drying out their wings just before dark. The dry fly fishing was stellar.
Many anglers return to the lodge or camp in the evening, leaving the river empty. If you’re crazy enough to night fish (I rarely am), you may find some of the best salmonfly fishing of your life. The combination of big bugs on the water and nocturnal brown trout may be worth the lack of sleep. Be safe and consider night fishing as the salmonflies hatch across the region.
Fish Elsewhere
Not surprisingly, the salmonfly hatch brings crowds to the river. For good reason, many anglers and guides plan their summer fishing trips around this renowned hatch. While following suit and joining the crowds is tempting, it may benefit you to think differently and fish elsewhere. With numerous anglers chasing the salmonfly hatch, other rivers and lakes have little fishing pressure. These fisheries offer incredible summer fishing and are potentially better than the salmonfly fishing on the busy rivers.
I have arrived at many streams within the vicinity of a river experiencing a salmonfly hatch and was surprised to be the only one fishing. I love the salmonfly hatch, but I also love solitary on the river. Thinking differently from the crowd may lead to fantastic fishing without the masses.
Many DIY anglers I speak with talk about their struggles with the salmonfly hatch. While it is a difficult hatch here in the West, one should be excited about it regardless of previous experience. I hope this article helps you and other DIY anglers when fishing the salmonfly hatch.
Please reach out or comment below if you have any further questions or insight on the salmonfly hatch. Also, please share with your fishing buddies if you enjoyed the article. I hope to see you out there chasing the big bugs this summer.
Do you want to learn more about the salmonfly hatch? Here are a few articles I used in my research for this article that I found interesting. I also linked many related articles throughout the post for your further learning.
2 thoughts on “The Salmonfly Hatch: Tips For The DIY Angler”
I’ve learned more from your blogs then from Fly fishing magazines. I’m going to try these techniques on the Colorado river in the next week or so.
Thanks for posting!
This comment means the world to me! Thank you so much Dan for reading and following along. Go get em!
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