Spruce Moths
Spruce Moth Prime Time
Spruce moth hatches have limitations. First, the hatch arrives when daytime temperatures can soar to 90-degrees F. or higher. The hatch typically starts during the first week in August, builds through the middle weeks, and dies before the end of the month. (Depending on air temperature and elevation, it may begin in early July and extend into late September.) Hatches get going around 8 A.M. or 9 A.M., just as the sun tops the mountains and warms the air. It lasts until noon or 1 P.M., when the heat really builds and the frenzy often dies. During a hot summer, emergency angling restrictions (especially in afternoon hours) may be placed on some of the streams where spruce moths are found.
A typical spruce moth day starts in the morning as air temperatures rise and the moths gain energy. As soon as they warm, they move out of the trees and begin searching for mates: first a few, quickly dozens, followed by hundreds or thousands depending on the location.
Spruce moths are strong fliers, but they are not immune to wind. In the Rockies, summer winds start early and deposit errant moths onto the water. The trout take notice, quickly moving from dark hiding places—around rocks, under logs, in the deeper pools and runs—into prime feeding lanes.
Trout often target moths in water shallower than 4 feet. If a Trico spinner fall is already in progress, the fish may switch from diminutive mayflies and focus instead on moths. A high-floating moth pattern with a Trico dropper tied off the hook bend is a good way to take advantage of both hatches. Look for fish along rocky banks where depth and cover offer security. You rarely focus on a particular rising trout—just cover the water.
Matching the Hatch
Fish are gluttonous and attack attractor drys like #12-14 Goddard and Elk-hair Caddis during early stages of the hatch. Occasionally, in their haste to devour a moth—or in an attempt to drown it—trout may miss your offering the first time, possibly even the second time, and return a third time to waylay their victim. If a fish misses, don’t worry that you may have jerked the fly away and created a commotion—it’s the same way naturals act as they try to escape the death tug of the surface film.
As the hatch progresses toward noon, gorged trout may get picky. For these fish, tie on a specific spruce moth imitation such as Gary LaFontaine’s Spruce Moth—a pattern that has proven its merit on Montana’s Rock Creek—or Patrick Daigle’s Spent Spruce Moth (available from Blue Ribbon Flies, blueribbonflies.com). Brief delays in action often end with a strong gust of wind blowing more moths out of the trees, which can prompt another frantic round of feeding.
When the hatch subsides and the fish return to their picky, late-summer routines, downsizing your flies and tippets may solicit a few more takes. Early in the hatch, 4X tippet is fine (you might even get away with 3X), but later in the hatch, 5X may be required. Another late-stage tactic is to bypass picky fish. Sometimes the best thing to do is say, “You win,” and move on to more willing customers.
Don’t Miss the Show
Anyone who experiences a solid spruce moth event is fortunate, and those who fail to take advantage of the current upswing, especially in Montana and Idaho, are missing out. In fact, owner Doug Persico of Fishermans Mercantile in Rock Creek, Montana, thinks the sin is worse for dry-fly anglers.
“I think that a guy who passes up a chance to fish the spruce moth [hatch] is passing on one of the great experiences in angling,” he says. “If you are a dry-fly fisherman, it doesn’t get any better. It beats the Salmonfly hatch, and it even beats my dearly beloved spring March Brown hatch. The weather is great, the fish are eager, and they love spruce moths. Even the big fish come up for them, so you get the best of it all.”
Ennion Williams, manager of Lone Mountain Ranch in Big Sky, Montana, has guided anglers during the spruce moth hatch for several years.
“It always came off around the beginning of August, but now it’s beginning in July and lasting longer,” he notes. “The patterns we use are the Stimulator or a light-bodied Elk-hair, size 10 or 12. The fish do get picky later in the hatch. You can change flies or tweak them to create a crippled version, or you can sink them.
Williams says there’s no aquatic stage to the spruce moth, but the fish do eat drowned moths below the surface. The Gallatin has had a massive hatch the last few years and it brings up some of the largest fish. “It just takes over during a time of the year that used to be pretty slow.”
That’s also the way it is on the Big Hole. Last year, I couldn’t help but consider my good fortune when the moths started out of the trees. The skies were blue and the morning was crisp enough to offer a shot of energy, but not cold enough to say that summer was ending.
There were only a few anglers spread over miles of prime stream. A half hour later I had landed a half dozen or more fish, including an 18-inch brown that broke my 4-weight rod. I raced to the truck, swapped the rod, and was back on the water ten minutes later to find the river alive with trout. Every cast drew a rise.
In the end, the value of the spruce moth hatch—or any super-productive hatch for that matter—is a chance to see Western trout at their best and to be able to tempt large fish to the dry fly. That’s the spruce moth hatch, a late-summer bonus for anglers lucky enough to find it. It’s not known how long the current spruce moth infestation will last. So get out there and take advantage while the taking is good.
Greg Thomas is a Fly Fisherman field editor, the author of five books, and publisher of Tight Lines. He lives in Ennis, Montana.
Copyright © 2012 Intermedia Outdoors
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