Yesterday was a big day for fly fishers here in Big Sky. Just like ski bums get excited about a blizzard bringing a deep powder day in the winter, our skies are now filled with the best hatch of the year, the salmon fly! Anglers spend their springs chasing this bug around Montana, and it's finally the Gallatin's turn to attract trout hungry anglers from around the state. Fish started looking up for the big bugs yesterday and are eager to eat off the surface. Smaller salmonfly and goldenstone patterns will be your most effective patterns, with larger stimulators getting some attention as well. Once the sun starts to go down fish have keyed in on salmon fly specific patterns.
Since this hatch only happens once a year a quick refresher never hurt anyone....
The hatch typically moves upstream. This is probably due to water temperatures, as Salmonflies hatch at a specific water temperature and generally the further downstream you go the cooler the water gets.
Because these bugs are so large trout can become gorged very quickly. If you find yourself beating your head against the trees trying to catch trout when there are hundreds of big bugs flying around my first suggestion would be to move up or downstream a few miles in search of trout that have not had the opportunity to gorge themselves or that have recovered from the initial smorgasbord.
Sometimes bigger isn't better. It is very common to get refusals or lots of short strikes on bigger patterns. If this is the case you may want to consider tying on a smaller Salmonfly or Golden pattern or even consider imitations of other insects like caddis or Yellow Sallies.
Choose your water carefully. Sometimes the biggest fish are in 3" of water and will only eat if the bug is within an inch of the bank and others will eat in some of the fastest, gnarliest water that you wouldn't usually give a second look.
Strip it or twitch it...sometimes they just want to see it dance!
May the force be with you!