Saturday was scum bag day on the Clark Fork River.
I’ve had better days of trout fishing in terms of fish caught.
But I’ve never been more intrigued by the hunt.
Light rain showers that morning doused the hopper action that had been a relatively easy answer to catching the river’s bigger rainbows, cutthroats and browns since July.
The super-sized meal attraction had been replaced by endless servings of hors d’oeuvres, especially in the foam lines and eddies. Mahogany duns, baetis and midge emergers were being served, and the trout were bellied up to the bar.
A cast of thousands had educated these fish during the spring and summer and at least five boats were ahead of us on Saturday just downstream from the confluence of the Bitterroot.
Nevertheless, fish were up and feeding in many stretches along the river as though it were their last supper.
Sometimes a rainbow or cutthroat would take my fly or emerger dropper with no hesitation as we drifted downstream.
The fun started and the intensity ramped up when large trout refused.
We’d anchor, get the right angle and attempt to break the code of getting a dry fly to drift naturally through multiple currents where the fish were feeding near shore.
Trails of white bubbles were the guides for placing our flies.
If there’d been naked supermodels dancing on shore, I wouldn’t have noticed as I focused my five-weight rod on an 18-inch rainbow gulping in the scum of a small eddy.
My imitations floated among dozens of naturals in a whirlpool of meringue. The trout appeared to be selecting only the choicest, drag-free morsels of perfection.
A master caster would have caught more fish Saturday, but flubbing a few presentations only heightened the anticipation and the thrill of the eventual take.
Many of these fish in the big, broad Clark Fork were as wary as spring creek trout.
It’s fall. The water’s low, slow and clear. The scum bags often were in less than a foot of water.
Could those whitish bubbles in the water be from fly fishers foaming at the mouth?
Although pollution is possible in some stretches, foam is a natural occurrence in nutrient-rich trout streams.
As leaves, debris and other organic matter decay in the water, they release surfactants that break the surface tension. This allows air to more easily mix with water and creates bubbles that like to congregate.
Natural foam is found year-round in amounts that depend on conditions. It’s especially prevalent on windy days.
Unless there’s too much phosphorous in the river, natural foam is harmless. Only 1 percent of the foam is the actual foaming agent. The rest is air and water.
Excessive phosphorous can result in nuisance algae blooms and decomposition that lowers dissolved oxygen levels and, ultimately, can kill fish.
But I was fishing the good stuff in the Clark Fork, far from the crowds of anglers pounding the scum bags of the Missouri River, where foam fishing is famous.
One eddy the size of a Volkswagen bus turned out to be a cesspool of torment. About eight rainbows were cruising under the cover of a foam blanket and rising unpredictably above a maze of minicurrents. Their backs slowly broke the surface and retreated like a seductress revealing a bit of leg during a bubble bath.
The eddy was a stew of live, crippled and dead insects concentrated in much higher numbers than in the main river current. The trout seemed to be ignoring healthy adult bugs on the surface. During our brief visit to the eddy, I found nothing in my fly box to match their desires. I could have stayed there for hours trying to catch their attention. But we had to drift on.
Minutes later, my buddy cast his mahogany dun pattern into a 50-yard-long foam line 5 feet off shore in three feet of water.
As soon as the fly, surrounded by bubbles, swerved slightly around a branch protruding above the surface, “Gulp.”
It was a 19-inch cutthroat of stunning beauty.
The line of bubbles had drawn him directions better than any Google map to where food was collecting and moving downstream.
“Oh give me some foam, where the rainbows roam, and the browns and the native cutts play …”
Contact Rich Landers at (509) 459-5508 or email firstname.lastname@example.org.
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