Matching the Hatch Basics


It probably happened right after you picked out your first fly rod. The fly shop owner or your buddy immediately ushered you to a huge display case of flies; hundreds of them captured and prisoners in tiny compartments with confusing names like Royal Wulff, Chernobyl Ant, Mister Rapidan or Adams. “Don’t worry,” he said as you stared, stunned and confused, at the smorgasbord, “all you need to do is match the hatch.” What the heck is that?

If you are brand new to fishing, matching the hatch means presenting a lure that mimics the natural food fish are eating. If your prior experience was with spin gear, you have already been doing this. After all, what logic drove you to select a 3-inch green Powerbait crawfish or a size 2 Mepps spinner? Given the variety of insects present on streams, matching takes on added complexity as you attempt to trick a fish to eat a fake fly.

One ardent school of thought claims success depends on exactly matching the existing insects regarding physical appearance, size, and color. At the opposite pole, an equally strident group argues proper presentation (drag free drift, etc.) is more important. As a new angler, occupy the middle ground and do the best you can regarding both. In his superb book, What Trout Want: The Educated Trout and Other Myths, Bob Wyatt argues “close is good enough” given many of the shimmering patterns in the display case don’t match any real insect, but still catch fish. Simplifying the problem to the extreme, he sums up with a simple theory:

“The Urinal Cake Theory states that if you put a urinal cake in a bowl of marshmallows and offer them to a child, there’s a good chance the kid will try to eat the urinal cake. And why not? There’s a degree of resemblance, or not enough difference to matter, at any rate. There’s no reason for the child to suspect there’s a urinal cake mixed up with the marshmallows, or even know what a urinal cake is. The kid certainly doesn’t suspect he might be being tricked.”

Given trout are much less intelligent than children, the idea of a highly educated fish employing a complex thought process leading to a bite is suspect. Wyatt believes trout do not know what a fly is and is not looking for exact physical features as food streams by in the swift current. After all, no matter how realistic a fly appears, it always has a hook hanging underneath to disrupt the illusion. The bottom line is when a hatch is underway, trout become used to feeding on a size, shape and, to a lesser degree, color of insect and will consume almost anything that matches.

Therefore, your strategy should be to select a range of sizes for a few reliable patterns known to be effective in your area (a key reason to buy at a local fly shop). There is no need to grab everything in the display case. Instead, purchase flies vertically (same insect, different sizes, different stages of the life cycle) rather than horizontally (an instance or two of everything). In most areas, having a robust selection of midges, mayflies, caddis and a few terrestrials will work just fine. If you can only afford one, pick either caddis or mayfly, but still get a few ants and mosquitoes. When acquiring your initial stockpile, ask the fly shop owner for a “hatch chart” showing the months when specific fly patterns are most effective and any other seasonal hatch guidance. You can also find hatch charts on the Internet by doing a simple search on the phrase “hatch chart” and the name of the stream, river or geographic area. To save a few bucks, use the hatch chart to avoid purchasing patterns that are only useful for a short window when a more generic fly overlaps the period. You can specialize later as you obtain additional budget and interest.

Rapidan River in Virginia
Rapidan River in Virginia

When you reach the stream, you should follow a disciplined assessment process before making your initial fly selection. First, take a few minutes to observe the water. If you see splashy rises, the trout are feeding on the surface, and a dry fly is a good choice. If you see a tail poking above the surface or a smooth bump, sip or bubbles after the motion, they are eating emergers. If all you see is the side-to-side flash of fish holding adjacent to the primary current, chances are they are eating nymphs.

Even though anglers love to fish dry flies, the reality is surface insects comprise an exceedingly low percentage of a trout’s intake since nymphs and emergers stay in the water column longer. Therefore, in the absence of any physical evidence, nymphs should always be your first choice. To determine the pattern to use, turn over a few rocks in the stream and observe the type of nymph clinging to the bottom; paying most attention to the size. If you want to fish a dry fly, follow the same approach by capturing an airborne insect. Another technique is to dip a small, fine net into the current seam and examine the result. Match the creature captured to the closest pattern in your fly box and fish it using the best practices associated with presentation. If that size fails to produce, drop a size and try again. If you remain unsuccessful, switch to your oddball patterns. Trout love ants, mosquitoes are always around, and sometimes just throwing something totally different like a stimulator will do the trick.

Match size, general appearance, and color. Beyond that, the more you know about the lifecycle and appearance of insects along with the fly patterns proven to be effective in matching that lifecycle stage, the more productive you will be. Two good references are Handbook of Hatches by Dave Hughes, and Matching Hatches Made Easy by Charles Meck.

Final Tip: Chances are you will end up buying plenty of flies that “look good.” A way to sort out those that catch fish rather than your wallet is to carry an extra fly box. When one of those “good looking” flies catches something, move it to the extra box. Over time, it will become your primary box; proven effective for your local water. The others? Don’t throw them out… you never know…

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