December 05, 2017
By Lance Egan
The best tip for fishing current is to consistently present a team of nymphs low and slow near the riverbed. While that sounds simple, doing it effectively and consistently requires a deep understanding of the complex, conflicting currents that occur from the surface to the bottom. Effectively fishing a dry fly is relatively straightforward.
It occurs in two dimensions and you see everything. The fly line, the leader, the fly, and the strike are all on the surface, making it easy to react to those visual cues. When you're fishing on the surface, you can detect and neutralize drag, see the trout take a fly, and set the hook accordingly. Everything is linear and in the same plane.
Skillfully drifting nymphs in comparison is unquestionably more challenging. All the intricacies that affect dry-fly presentations also apply under the surface, but with the added complexities of three-dimensional drag and an unseen strike that takes place near the river bottom.
To present your flies slowly and close to the river bottom you first have to conceptualize the water column from the surface to the bottom. In oceans and deep lakes, the stratification of the water column is based mostly on temperature, light, and as a result, food.
For nymph fishermen, the water column refers to the idea that at the surface, the water moves significantly faster than the water near the riverbed, which moves slowly. Trout spend most of their time feeding in this lower, slower layer of water at the bottom of the water column, and getting your nymphs into this bottom layer without vertical drag from the surface current above is what sets a good nymph fisherman apart from a mediocre one.
Once you're in that zone, and in a suitable feeding lane, you must detect strikes that are unseen through use of some sort of visual indicator. These factors make nymph fishing considerably more technical, specialized, and demanding than dry-fly fishing. Don't get me wrong, I enjoy catching trout on dry flies as much as anyone, but I also take great pleasure in solving the complexities involved in subsurface fishing.
There are trout streams on every continent, and every waterway has characteristics that make it special, but all moving waters pose the same challenge of conflicting currents. To catch fish consistently, fly fishers must understand the influence these currents have not just on their flies, but on the whole subsurface rig, and also be able to neutralize those currents so the flies drift free of drag.
Every river has the fastest water at the surface, and progressively slower water as you get deeper, with the slowest water near the bottom and along the banks, which combined are called the riverbed. It is the slow layer of water near the riverbed that trout call home.
The slow water along the riverbed is created by friction between the moving water and the stationary structure. The makeup of the riverbed greatly affects the velocity of the passing water. Uneven, large structures such as boulders or cobblestone slow the flow more than relatively smooth gravel or sand bottoms. Both types of riverbeds create suitable habitat for trout.
The Nymphing Troposphere
Trout occasionally chase swimming foods. They also temporarily move to the surface to gorge on emergers, adults, and terrestrials. However, the greatest abundance of food is normally concentrated near the riverbed. The riverbed also offers protection and camouflage. These factors, combined with the decreased water velocity, make the riverbed the preferred habitat of trout in all rivers.
The illustration on this page shows the vertical profile of current in a typical trout holding area near the riverbed. Notice the significant slowdown near the riverbed compared to the water at mid-column and near the surface.
Beginner fly fishers have likely heard and heeded the advice to "get your indicator moving the same speed as the water's surface." While this is a decent starting point, ideally your flies should drift at the same speed as the current near the riverbed, which is much slower.
A floating strike indicator moving at the speed of the surface current will tow your flies rapidly. Even if your flies are heavy enough to stay near the bottom, the proper drift speed is impossible to achieve if your indicator is moving at surface speed, because your flies are tethered to the tippet, leader, indicator, and fly line. Let's tackle these layers of current individually.
Surface current is the most common negative influence on fly presentations. The surface current is rarely uniform from bank to bank, and therefore casting across currents of varying speeds creates drag. Drag, as defined by Fly Fishers International is: "An unnatural pulling of a floating or submerged fly such that it moves at a different rate than the current."
Surface drag isn't only a nymphing issue, it affects dry-fly, dry/dropper, streamer, wet-fly, and nymphing presentations because each of these rigs requires you to have at least some line on or through the surface. It's especially critical when you're trying to present flies low and slow because the parts of your fly line, indicator, or leader that are drifting quickly on the surface will tow your flies unnaturally fast.
To minimize this effect while fishing current, reduce the total surface area of anything on or near the surface such as the fly line, leader, tippet, and especially the strike indicator.
Smaller diameter equals less surface area, so use a thinner diameter leader and tippet. The indicator must be visible, and needs to have enough buoyancy to suspend your flies, but a strike indicator that is too large becomes a sail that pulls your flies unnaturally.
Remove as much of the line and leader from the water as possible. High sticking, or extending your arm and elevating the rod to lift the fly line and leader off of the surface allows the indicator and flies to drift relatively uninhibited.
Finally, learn to mend. Mending is simply repositioning the line on the water to avoid drag. When you're nymphing, you often mend immediately after you cast, and you often need several mends throughout the drift to get a long, drag-free presentation.
Most fly fishers are familiar with basic mending techniques but here are a few tips to improve your mending:
Use as little slack as practically possible. Too much line creates difficulty when you try to set the hook on a fish. When you add slack line to mend, take up the slack between mends and reintroduce slack only when you need it.
Use a downstream mend when it's necessary. Generally when you are in a static position, it is best to move line and position slack upstream of the indicator, but some situations require a downstream mend. For instance, if the flies and indicator are in faster current than the water between you and the feeding lane, a downstream mend keeps your rig moving at the proper speed.
Mending involves timing. You must introduce slack before the line straightens; otherwise you temporarily lose your dead drift, and if a fish is considering your fly at that moment, it's a lost opportunity.
One of the most common novice mistakes is attempting to move line up- or downstream without firstâ€¨ lifting the fly line off the water. Mending is most effective if you start by first lifting the rod to help the line break free of the surface tension, and then with a high, elevated rod, flick the rod tip to reposition the line.
Use aerial mends. A reach cast, curve cast, or "S" cast can add slack or position line properly before it lands to help you get a drag-free drift. Aerial mends also make less surface disturbance than regular mends, making them ideal for spooky fish and flat water.
Overcoming surface drag while fishing current is already in the wheelhouse of most experienced fly fishers, and it's the easiest drag to beat because it's observable. The toughest drag to beat comes from difficult-to-detect subsurface currents.
The illustration on this page shows the water column contains layers of current with varying speeds. These currents affect your leader, tippet, and flies much like surface current except in a three-dimensional vertical form rather than just horizontally.
When describing these currents I often equate them to air flow (wind) near the earth's surface. Much like water, wind slows as it encounters obstacles like trees, buildings, or mountains.
In general, wind closer to the ground is slower than it is up in the jet stream. Surface friction with the ground causes the wind near the ground to move slowly relative to the nearly frictionless flow up in the atmosphere. Water flowing near the riverbed slows down for exactly the same reasons. In some areas with large substrate, the water at the bottom of the river even flows back upstream due to the whirlpool effect caused by obstacles along the bottom.
Getting flies to the right depth and drifting the same speed and direction as a natural benthic macroinvertebrate requires you to negate all the influences of the varying current speeds from the top of the water column to the bottom. The most effective way for most fly fishers to do this is to change their terminal tackle.
Many fly fishers unknowingly enable/enhance/increase drag by the way they rig their tippet and leader. Most fly fishers purchase a 9-foot or 10-foot tapered leader from their local fly shop, add a couple flies with a little tippet between them, add some split-shot, and an indicator. This common and easy rig catches some fish but isn't designed to minimize subsurface drag.
The bulk of commercially available tapered leaders follow a 60/20/20 formula: 60% butt section; 20% taper; 20% tippet. A typical 10-foot, 4X trout leader therefore has roughly a 6-foot butt section of .021"-.022" diameter, a 2-foot tapered section, and only 2 feet of .007" (4X) tippet. The long, large diameter butt section is what causes excessive subsurface drag. Most fly fishers I see on the water add their strike indicator to the butt section of these leaders, which are designed to cast nicely, but not properly designed to cut through the current. I did too, for many years, until I realized that the butt section of my leader had too much surface area and was catching subsurface currents, and creating drag.
An easy way to overcome this problem is to reduce the overall diameter of the leader and especially the parts reaching through the fastest part of the water column. A typical run of trout water with an average depth of 3 feet and lively speed requires at least 6 feet of leader between the indicator and the flies to allow the rig to achieve adequate depth.
You need to use a leader 2 to 3 times the water depth because the indicator is being towed at surface speed while your flies and/or weights should be drifting at the speed of the slow current near the riverbed. These conflicting speeds force the leader into a 30- to 45-degree angle, and the curve in the leader position can also add leader distance between the strike indicator and the flies. A 3-foot leader will not work in 3 feet of moving water; the leader needs to be much longer than that.
The easiest way to reduce drag is to start with a 6-foot or 7.5-foot tapered leader (rather than 9 or 10 feet) and then add 3 or 4 feet of 4X-6X tippet with a blood knot or a tippet ring. This ends up with a similar total length leader as a factory-made 9- or 10-foot tapered leader, but you've got a much shorter butt section and much longer tippet section. The thin diameter cuts through the water column quicker with less influence from subsurface currents, and you'll not only get more strikes, you'll be better able to detect them.
A better way to decrease the impact of subsurface currents is to avoid commercial knotless leaders altogether and build your own tapered leader. This is not a new concept, but still hasn't caught on with the majority of fly fishers. I first read about the benefits of a custom-made nymphing leader in Gary Borger's book Presentation (Tomorrow River Press, 1995). In it, Borger describes his DD leader, or "dead drift" leader, and following his advice changed more than my catch rate, it changed the way I thought about subsurface drag.
While the primary leader I tie today is a bit different than the DD, the principles remain the same. By building my own leader for nymphing, I have control over the length and diameter of each leader section and can choose the ideal material for each part. For instance, I use nylon monofilament for the butt section and then transition to fluorocarbon for any subsurface part of the leader. Nylon is less dense than fluorocarbon. It floats, and it's easy to spot, so I use it for the leader section where I'd normally attach my strike indicator. Fluorocarbon is denser, clearer, and has greater abrasion resistance when compared to nylon, making it the best material for the subsurface portion.
Keep in mind that my leader is a starting point only, and that I alter it slightly based on water depth, clarity, speed, and the type of flies I'm using.
I attach the weight below the flies because it's is the best way to keep contact with my flies and detect strikes. The flies are also far less likely to snag the bottom, since the hooks are drifting just above the riverbed, with only the weights contacting the bottom substrate.
Both flies are tied on the tag ends of my tippet knots or "droppers." Tying your second fly to the bend or eye of the first fly is common, but causes the top fly to drift unnaturally, and makes it more difficult for a fish to take because the top fly has two lines tied to it. Fish have to take the fly at just the right angle because the two lines act as a hook guard.
A fly has the most natural drift when it only has one piece of tippet tied to it. If you don't already use droppers, make the switch and you'll see more fish in the net.
Using a European nymphing rig without a suspension indicator is in many cases the best way to defeat drag. In the Euro style, the fly line, butt section of the leader, and "sighter" are all held above the surface with a long rod and outstretched arm. The sighter is a visual indicator tied into the leader, often made of hi-vis monofilament.
Using a sighter eliminates the drag caused by a floating strike indicator and floating fly line. In a Euro system, thin tippet (4X-7X) is connected to the sighter and extends all the way to the weighted flies. With no thick leader sections on or in the water, the effects of drag are greatly reduced.
You get better strike detection with this system as well, mostly because you rely on weighted flies rather than split-shot to achieve depth. While adding split-shot, putty, or Twistons can help get your flies to the bottom, the drawback of using these sinkers is that you are in direct contact with the weight, not the flies, so it's difficult to detect when a trout picks up your drifting fly. When the weight is in the flies, you're much more likely to notice it. If you do it properly, Euro nymphing allows you to achieve the same depth with less weight, making casting a bit more enjoyable.
Another advantage of the Euro system is that it allows you to fish through a wide range of depths and water types. Euro nymphing is especially effective in shallow water, edges, pocketwater, and tight, narrow seams. Riffles, plunge pools, and mid-stream obstructions are also favorite types of structure for this method. Like all techniques, Euro nymphing has its limitations, but the vast majority of the time it is my most effective technique.
I tie my own Euro leader using Maxima Chameleon for the knotted butt section and Cortland Indicator Mono for a sighter. Euro leaders should be long, and perform best in the 18- to 22- foot range, including the butt section.
Regardless of which leader you use, or whether you use a strike indicator or not, overcoming drag both at and below the surface is paramount to your success. If you ignore drag, you'll still catch some fish, and from time to time, your nymphs will actually be drifting the way they are supposed to. But if you study and understand how surface and subsurface currents affect your drifting nymphs, and you modify and control your terminal tackle to defeat it, you'll be a better fisherman, and your catch rates will show it.
Lance Egan is a three-time World Fly Fishing Championship medalist, a three-time National Fly Fishing Champion, and member of Fly Fishing Team USA. In addition to guiding, he works at flyfishfood.com and recently released the instructional film Modern Nymphing, which is available on DVD ($30) or on demand at vimeo.com ($20). Lance lives in Lehi, UT with his wife and two children.