An Ode to Foam

An Ode to Foam

When all else fails, a good pile of dirty bubbles can save your day

  • By: Chris Gerono
e hadn't caught a fish all day. It was a classic skunking. My buddy, Brandon, and I were so new to fly-fishing that we didn't even know how badly the odds were stacked against us. The river we were fishing was a classic southern Pennsylvania mountain stream--boulders strewn everywhere, the banks choked with thick vegetation. We were there chasing a rumor passed to us by a whitewater kayaker (seldom a good source of fishing intel) that this river held wild trout. Our strategy was simple: We threw flies at every likely looking pool and run that we encountered--with zero results.Toward the end of the day Brandon was standing on a boulder and casting a large attractor to the top of the pool. While sitting on the bank watching him fish, I noticed a three-foot-wide pile of foam floating next to his perch. Instinctively, I told Brandon to drop his fly on top of it. The fly landed right in the foam and within seconds was eagerly sucked down. A few minutes later Brandon landed and released an exquisitely colored nine-inch brown. It was the only fish of the day and it arrived at the right time--we had been about to conclude that the stream was devoid of fish and that the kayaker was full of it. You'll find foam piles on just about every river you'll ever come across, and the tactic is simple: Throw a fly on them. Foam piles are highly coveted by trout because they provide almost all of a trout's needs at the same time: cover, food and a break from fighting the current. Although foam piles of any size are good places to toss a fly as you drift or wade by, the type you'll want to target for really big fish are the large metropolises of bubbles that collect in the eddies that form around almost any sort of structure. Look for these foam piles around woody debris, a cut bank or a boulder. Foam piles come in different shapes depending on the setting. You'll see ones that spiral around and behind a rock or log, and others that hover in the upstream eddy created by a fallen tree. Those found on the upstream side of a log or tree are produced when the current dumps off its bubbly, insect-laden cargo against the log as the water runs beneath it. Trout found in these areas generally hold in stationary feeding positions and gobble up insects as they drift by. Sometimes an entire pool or back eddy will be blanketed by a wide foam pile. These large blankets of foam do not concentrate insects as efficiently as the other types, but trout still cruise underneath and rise for trapped insects. What makes foam in the first place? As a river or stream flows through runs and riffles, it churns up organic material and dirt, mixes it with air, and covers it with a film of water. The bubbles produced by this eggbeater effect meander downriver in little caravans guided by the currents. Eventually many of these caravans link up into large piles of bubbles that collect in eddies (along with all sorts of natural and man-made detritus). Certain stream conditions provide ideal situations for bubble production. For instance, streams that are stained with high concentrations of tannic acid generally have good supplies of foam. Weather can also affect the number of fishable foam piles; a good time to find them is during periods of rain or high water. The same currents that gather bubbles into foam piles also gather insects. Emergers, spinners, cripples and terrestrials that can't get off the water before they reach an eddy are trapped and concentrated in the foam pile. For aquatic and terrestrial insects alike this is almost certainly a death sentence. But for trout, it's an all-you-can-eat buffet. Fishing foam is exciting because most of it is done with a short line and a dry fly. All you need to do is drop your fly on the foam pile and let it float as a natural would. The trick is to get the fly through the foam and onto the water's surface, since an insect trapped in the upper levels of a thick bubble pile doesn't present itself to the trout properly--and may not even be visible to them. Twitching your fly slightly will sometimes stimulate a strike by simulating an insect struggling in this natural bug collector. Another technique that draws strikes is to toss a weighted fly, such as a Woolly Bugger, through the pile and jig it just beneath the foam. Always take your time when approaching a foam pile. The fish might not be able to see you, but it may still detect you if you are not careful. Before making your first cast, look for holes in the foam: When a fish sucks an insect out of the foam, it leaves a hole. Keep watching this area for feeding fish. If you see a rise, drop or drift your fly into this spot and get ready for a take. Other times you may want to cast your fly a foot or two in front of the foam pile and let it drift into it. If a fish does not hit in the first few seconds after it collects in the foam, try twitching it. Repeat this process until you feel you have thoroughly worked the area. Remember that the trout may not see your fly right away or may be distracted by other entrée options. Often, the biggest fish in the river lives under a mountain of foam. A well placed fly or weighted streamer can draw strong hits. If you are not careful, before you know it the fish will have run your leader over, around and between whatever snag or rock is creating the foam eddy, so be ready.