With snow on the ground, leaves changing, elk bugling, and rivers running at winter flows, fall fly fishing is getting into full swing in the Rocky Mountains.

Fall is hands-down my favorite time of year to fish. The crisp morning air burns the summer heat from my lungs; perhaps more importantly, the cooling temperatures thin the herds on the river. Here in my home state of Utah, it’s only during fall and winter that I feel I have enough elbow room to properly cast on the Provo River.

The increased solitude is nice, and few sights rival the astounding beauty of ruby-red oak leaves and golden aspens bordering a river. The best part about fall fly fishing, though, is the fishing itself.

Fall fly fishing is a different game than any other time of year, though. Fish behave differently, hold in unfamiliar water, and are spookier than normal. If you spend enough time watching before you cast, you’ll soon enough figure out the behaviors of trout as the end of the year approaches.

It’s spawning season

The first thing to be aware of during the fall is that it’s spawning season for brown, brook, and bull trout. Some rainbow trout spawn this time of year, though the vast majority of them spawn in spring.

This is important for two reasons: brown trout are much more aggressive this time of year, and if you don’t watch where you step you’ll negatively impact your local river’s brown trout population.

As the spawn nears, browns build “redds” in the riverbed. These are big bowls of clean, moss-free rock or gravel. Usually, you’ll see a minimum of two or three trout on one redd, though larger redds draw larger crowds of fish.

The most important lesson in fall fly fishing to learn is this: don’t step in the redds. I mentioned above that if you don’t pay attention to where you step you can negatively impact your local river’s brown trout population. If you walk through the redds, you’ll crush any fertilized eggs laid and buried in the rock and gravel.

Watching where you step will help the brown trout population flourish.

Along with that comes another cardinal rule of fall fly fishing: don’t fish to actively spawning trout. The reason for this lies in the same vein of wildlife science that keeps us from shooting too many does or cows, or hunting them during critical herd growth periods. It’s much easier to manage a herd by managing the male population than allowing widespread killing of the females.

With big game it’s easy to tell males and females apart. With fish, you really can only tell once they’re out of the water. So not only is fishing to spawning trout a toss-up on whether or not you’ll be removing a female trout from your river’s spawning population (female brown trout produce around 900 eggs per pound of total body weight at the time of spawning), but doing so place undue stress on trout as well.

Back when I first started fly fishing, I remember catching some big browns just before Thanksgiving. What I remember most, though, is how a few of the fish I caught spilled piles of eggs all over my waders once I pulled them out of the water and into my net. Female brown trout will drop their eggs at the slightest hint their life may be in danger – call that instinctual species preservation. If those eggs aren’t deposited in a redd, they’ll be washed downriver and remain unfertilized.

So long story short – don’t fish to actively spawning trout (the ones on redds) and don’t walk through the redds.

Streamers, eggs, and more streamers

Bull elk get loud and mean during the rut. While brown trout can’t bugle, they get similarly aggressive this time of year.

Streamers work so well this time of year because they trigger a trout’s natural defensive instincts. Now, some anglers argue that fish eat streamers because the streamer looks like bait fish or small trout (which is true, but only once a trout reaches a certain size; even then, they’re rarely exclusively piscivorous. If that were true, I wouldn’t have caught a 27-inch rainbow trout on a size 22 mysis shrimp). Others argue a streamer just triggers natural aggression from a trout. Either way, the presence of big streamers around or near redds is a surefire way to coax viscous, aggressive strikes from big trout.

A personal favorite streamer at this time of year is the Zuddler in yellow or green. The bulky head and skinny tail makes it look enough like a sculpin that it can pass for some sort of baitfish, but the rabbit tail swims beautifully in the water.

The other must-have fly this time of year is your egg patterns. As eggs are laid, a few will get washed downriver. Trout feed opportunistically on these high-protein snacks. Any eggs imitation thrown behind a redd is as close to a sure thing as you’ll ever find in fly fishing.


Don’t forget the dries

A lot of anglers – myself included – get so caught up in throwing streamers this time of year that we forget the importance of fall dry fly hatches.

Blue-winged olives are the main hatch, with the last of the pale morning duns out as well. October caddis show up briefly, and midges will always coax fish to the surface.

The trick in the fall is similar to early spring fly fishing. You need long leaders, small flies, and perfect drifts. With low, clear water, trout have a lot more time to examine flies, get spooked by leader, or see subtle micro-drag on a drift that’s not quite perfect.

Fall fly fishing is my favorite time of the year since it’s when the largest trout come out to play. Add that to the gorgeous scenery and great weather, and you may have a hard time hunting as much this year if you set the rifle aside for a day or two and give the old fly rod a cast.