The term “Emerger” is often heard when discussing fly fishing techniques, but is not always explained in depth. To the novice angler this term can cause more confusion and hindrance than help. The term emerger can refer to a variety of scenarios. They common theme is that this term refers to an insect on its way to the surface to hatch. The importance of this vulnerable state becomes very clear when thinking of feeding from a trout’s point of view.

Wild trout are subject to the harshness of nature which make them experts of mastering the delicate balance of calories consumed versus calories burnt that keeps them alive. Swimming to the surface to eat a fly burns calories. If that fish is surfacing to eat, they better catch that bug, otherwise it was a waste of their precious energy. This is even more important for trout living in rivers, where holding their feeding position costs more energy than one in a lake. Trout prefer to surface and eat insects which are vulnerable, which in turn, makes them an easier meal. It’s a game of odds, and surfacing to a emerging insect increases that trout’s odds of returning to the bottom with an insect in their mouth.

An emerger is a broad term that refers to an aquatic insect that is surfacing to shed its exoskeleton and turn into a winged adult. This can be in the center of the water column on their way up, just below the surface of the water, or in the surface film where the insect is shedding its skin. Generally, the two latter situations is what most people are talking about when referencing emergers. When insects are rising to the surface in the water column, I like to refer to them as an “ascending” nymph. This distinction is important because fly choice and your approach changes when imitating an ascending nymph.

The surface tension can be incredibly taxing for an already exhausted nymph to penetrate, and the trout know this. When you see trout feeding directly below the surface this is often what these fish are feeding on. If fish are breaking the surface, but ignoring your dry fly they may be keyed in on insects which are struggling to break free from their old skin or “nymphal shuck” they are shedding. Due to the nymphs being exhausted, distracted, or stuck in their old skin, focusing on meals like this help trout increase their odds of successfully feeding.

For insects just below the surface or in the surface film, there must be an element of buoyancy present to help suspend the fly in the film. Here are some of our favorite emerger patterns for targeting fish feeding closer to the surface: Film Critic, X2 Caddis, CDC Emerger, or a Poxyback Emerger. All of these flies contain a shuck or the rear is dropped into the water to imitate an insect shedding its old skin. For nymphs which are ascending to the surface from the riverbed, soft hackle type patterns are more appropriate. Here are some shop favorites: Simple Soft Hackle, Partridge and Pheasant, Soft Emerger, or a March Brown Emerger.

For the more buoyant emergers which I listed above, fish them like you would any other dry fly. Often mayflies, caddisflies, and midges do not emerge in rapids. Insects need more calm water to safely emerge without being splashed back under. You’ll often find trout feeding in the middle of runs or especially towards tailouts. This is a place where the freshly hatched insects are funneled to the feeding trout. . If they are too small to see, consider tagging them behind a larger, more visible fly like a Chubby Chernobyl, or Stimulator. Dead drifting these type of emergers, which mimic insects in the film, is the most appropriate way to present these flies.
The second set of emergers listed mimic ascending insects, and the most appropriate way to fish those is to fish them on the “swing”. Cast angled upstream and across with your emerger. A few upstream mends will allow the flies to sink, once they have made their way deeper let your fly line pull tight, and it will swing your flies towards the bank you are standing on. This technique will swing the flies from deep up to the surface, effectively imitating an ascending insect. You may also raise your rod tip during the swing if you spotted a fish feeding, this will exaggerate the ascension even further. You may want to fish this technique with a secondary beadhead nymph in front of your emerger, or some split shot to get your fly down.

Paying attention to the nuances of insect hatches is not essential to have a successful day on the water, some may say the advantages are only marginal. During large, consistent hatches fish have the luxury of being picky and choosing easier meals over others. During extremely large “blanket” hatches this is even more important as you must offer something that stands out as an easy meal. Fish also choose to feed on vulnerable prey, emerging aquatic insects are one of the many vulnerable states that trout key in on. For these reasons, fishing emergers can be advantageous when targeting trout. Most importantly, studying the intricacies of aquatic insect hatches will give you a deep sense of the interconnectedness of the ecosystems we choose to recreate in.
-Simon