When Big Bugs Hatch

Late spring/early summer marks the annual hatches of big stoneflies and mayflies, and the annual migration of anglers who come to cast meaty flies to meaty trout.

Photo by Justin Karnopp

By Justin Karnopp

An aluminum hatch was in full swing. Not by coincidence, so was the salmonfly hatch, and it was my job to find the two anglers in my boat some fish, despite the significant crowds of anglers who had been pounding the water for days. The fish were wary of stoneflies and I hoped that the fishermen in my boat possessed the skill to reach the tough spots.

I pulled over at the head of a grassy bank and instructed one of the gentlemen to drift his fly in front of an overhanging alder branch. He suggested that he would like to walk around, get below the tree, and cast upstream to the fish that had just boiled on a natural stonefly. That wasn't an option.

This fish had been fooled before and had chosen his lie because of the current structure. A cast from below would not produce a good dead-drift and there was a high probability that the leader would spook the fish. I told the angler he had only one chance.

If his first drift was perfect, the fish would probably take. But if he short-lined the drift, the fish would refuse and not come back. It would take significant slack to get a good drift, and then he would have to remove that slack quickly when the fish took, but not too quickly, because of the way that trout generally take stoneflies. Then he would have to pull the fish hard to the left to keep it from wrapping around the snag just off the bank. "Go ahead and make your cast," I said.

Understandably, the guy gave me a quizzical look and asked, "Aren't there some easier fish to catch around here?"

"Nope. These fish have seen a lot of flies the past two weeks. They're still taking stones, but you have to be able to put them into the little crannies that they have retreated to," I replied.


The largest of the mayflies, for all you Latin lovers, is the Hexagenia limbata, commonly referred to as the Hex. These giant yellow mayflies inhabit lakes and the slow, meandering sections of some rivers.


This is an extremely fickle hatch. Hexes are even more sensitive to weather than green drakes or stoneflies. I would advise against loading up the truck for your big Hex adventure until you've called a few fly shops or talked to other anglers about the condition of the hatch.


The nymph of the Hex spends daylight hours buried in mud. A couple of hours before dark they start to move about and feed. Fish a weighted nymph just off the bottom underneath a strike indicator. Using a jigging motion, lift the fly just off the bottom and then allow it to resettle in the silt.


Just before the sun kisses the horizon, adult mayflies begin hatching. Forget about light presentations on light tippets. A big, cumbersome Hex makes quite a commotion on the surface. Let the fly sit, and then twitch it periodically to imitate the struggling of the naturals. Since you're fishing at or near dark, there is no reason to fish a light tippet. Start with a 2X leader and work your way to smaller tippets if you get refusals.


Cripple patterns are extremely effective when imitating the Hex. The Quigley Cripple on a No. 8 hook is a good choice. For a standard adult pattern, the only one I have relied on is an extended-body Parachute on No. 6 and No. 8 hooks.


Most dry-fly action takes place at or after dark. Be sure to check local regulations before fishing at night. Always bring a headlamp and plenty of mosquito repellent when fishing a Hex hatch. -- Justin Karnopp


"I thought that trout were supposed to be easy to catch during the salmonfly hatch," he said. I've heard the same comment dozens of times over the years, and you probably have too.

When summer spurs the hatches of big bugs such as the salmonfly, golden stone, and green drake mayfly, anglers flock to Western streams to get in on the action. The big attraction of these hatches is three-fold: One, it is just plain fun to see fish come up and take big dry flies; two, this is the best time on many rivers to hook the biggest fish that elude anglers the rest of the year; and three, the aforementioned angler's perception seems to be a widely held belief.

Many anglers think that if they show up during these hatches they are sure to leave a good chunk of the trout population with sore lips. This isn't always the case.

First of all, these hatches are weather-dependent. Stoneflies like warm, sunny days, and drakes like overcast and a little rain. I've been blessed with days when I've had both, and a smorgasbord of big bugs drove trout into an all-out feeding frenzy. However, this is not the norm, and weather is not something that is within our control. Due to the popularity of these hatches, trout are under intense fishing pressure and become skittish. Anglers who come prepared with some fundamental presentation skills, the right gear, and realistic expectations can enjoy these fantastic hatches to their fullest.

At the start of a stonefly or drake hatch, the majority of fish haven't yet keyed on the bugs. However, the older, bigger trout that have been through a few of these hatches usually catch on quickly.

Try fishing the riffles, runs and pockets where trout would normally hold, and you'll be surprised at how many will be willing to take a big bug, even though you may not have seen any rises to the sparse number of naturals. That said, do some research and find out when the prime time for a stonefly or drake hatch is on a particular stream, and then try fishing it a week or two before. You're sure to find less competition, at least.

There is generally a short window during a stonefly or drake hatch when the bugs are out in full force and every fish in the river is co

ming up after them. If you are lucky enough to hit the peak of the hatch, you will experience dry-fly trout fishing at its best. Once this mayhem has subsided, however, the fishing becomes more challenging. The fish have seen and tasted lots of imposters. They learn to tuck themselves into places where bugs that are attached to leaders become easy to distinguish from the real thing. This calls for some advanced presentations. Of course, on rivers where anglers can fish from a boat, these areas are much more approachable. But we're talking about the bank angler here.

I'm a real believer in the downstream presentation, especially when it comes to presenting stoneflies. This is a difficult tactic that requires good control of slack line. A grass-lined bank is a promising place to look for trout feeding on stones. In many cases these banks drop off quickly, restricting the angler to hugging the bank. Vegetation behind the caster often forces an angler to keep the fly line out over the water.

On a river-right bank, a right-handed caster has a couple of options for getting a good drift to the trout hanging below. One option is to face downstream and false cast off the opposite shoulder until the appropriate length of line is out. Upon stopping the rod on the forecast, the fly line goes taut and starts to drop to the surface. Before the line hits the water, an upstream reach will land the fly just below the angler, leaving plenty of line above his/her position available as slack. The angler can then feed that slack out quickly by making a long, side-to-side motion with the rod, keeping the tip just off the water's surface. The tension of the line pulling on the water will feed the slack quickly while maintaining the dead drift.

This takes some practice, and setting the hook is a real challenge, especially if a trout takes while you're still feeding slack. You will miss fish with this presentation, but you will get many strikes from fish that otherwise would have never struck.

For those who are not comfortable casting off the opposite shoulder, there is another option. The angler can turn and face upstream to work out the appropriate length of line. When the line straightens at the end of the cast, make a quick clockwise circle with the rod, landing the fly just downstream of you. This one takes a little practice but is easier than it sounds.

I use the downstream presentation whenever possible when fishing big bugs. It ensures that the first thing that a fish is going to see is my fly, not my leader. I typically catch my biggest fish with this presentation because it is often the only way to get a fly to wily fish hiding in difficult lies.


During the stonefly migration, trout feed on the nymphs voraciously. Flyfishermen have great success by swinging a nymph toward the bank to mimic a migrating stonefly nymph. Some spin fishermen who head to the river in June are catching on. One such angler is Rich Kortge.


"I fish riffle water and swift runs," Kortge says. "Don't be afraid to fish in substantial current -- it works.


"Two methods have worked well for me. A black Panther Martin with yellow spots is a killer. Match the size of the spinner to the depth of water you're fishing. Try a small black and orange Kwikfish with a split shot about 18 inches above the line to get it down.


"With either setup, cast and fish it into the bank, let it hang, and then begin a slow retrieve. Fish from the top of the riffle down; walk, if necessary, to keep the lure near the bottom." -- Justin Karnopp


Trout don't sip stoneflies and drakes. The most common take is for the fish to rise up next to the fly and turn on it, taking the fly on the way back underwater. I'm not sure exactly why they take them in this manner, but they do the same thing when feeding on another big bug, grasshoppers. Many anglers make the mistake of setting the hook when they see the fish come up, when the trout is actually next to the fly and hasn't even mouthed it yet. Teach yourself to wait until the fish has taken the fly and re-entered the water.

Just because the trout are selective, don't assume that you need to be struggling with a 7X tippet on your No. 4 Stimulator. The last thing I will change is my tippet size during these hatch events. If the presentation is good, the fish will more than likely take the right pattern on a 4X tippet. Light tippets will cost you plenty of fish and leave many a trout with a detrimental obstacle protruding from its snout.

I rely on basic, proven patterns when fishing stoneflies. Every year there is some new, hot pattern bulging with rubber legs, Flashabou, eyes, feelers and the like. I stick to the patterns that I have faith in, and that are easy to tie.

Stimulators, Sofa Pillows, Clark's Stones and the Norm Woods Special are all basic hair-wing patterns that have proven themselves for decades on Western trout rivers. I tie these in a number of sizes and in orange and yellow to imitate the salmonfly or golden stone, respectively. Sometimes an individual fish may refuse one but will take the other.

The one problem with these flies is their tendency to twist a leader when false casting because of the heavily hackled thorax. One solution is to tie a sparser thorax, which still seems to fish just fine. Another trick is to fish with fluorocarbon tippet at the end of your monofilament leader. There is a common misconception that fluorocarbon will sink your dry flies, but that has never been my experience. Fluorocarbon seems to resist twisting better than monofilament.

Green drakes are easy to mimic with a big Adams-style pattern with an olive body and chartreuse thorax. However, selective trout don't always buy this. I really like an extended body, Comparadun-style tie. This pattern seems to have the profile that fools big fish. Noted fly-tier Shane Stalcup's Green Drake is a very good parachute pattern, but it does have the aforementioned tendency to spin a leader. Check with your local fly shop for this particular drake pattern. Bring a good variety of patterns when fishing a drake hatch.

I know, I know, you didn't come for the salmonfly hatch to nymph fish, but sometimes the fish just aren't coming to the surface for the big bugs. This is typ

ical on cold days, and in the mornings before the bugs start to move around. Don't assume that the trout aren't eating. The action below the surface during stone and drake events can be phenomenal, especially for big fish.

The nymphs of the golden stone, salmonfly and green drake are big chunks of protein, and trout relish them. The basic Girdle Bug is the standard stone nymph pattern, tied in bronze or black for the golden stone or the salmonfly, respectively. Other good patterns are the Kaufmann's Stone and Keystone. The venerable Hare's Ear tied in olive on No. 6-8 hooks works fine as a drake nymph.

* * *
The emergence of the big stonefly species and the big mayflies is no secret to the legion of fly anglers who have these events marked on their calendars annually. The trout catch on quickly, and those anglers armed with the right patterns and techniques will come home with big-fish stories.

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