Breaking down a fly hatch can be very difficult for anglers just starting on their fly fishing journey as well as those who have some experience on trout streams. Staying ahead of the game requires anglers to be observant and intuitive. Paying attention to the subtle nuances that occur before and during a hatch can be the difference in an epic outing and a disappointing one. Not all hatches are the exactly the same, but in this article we will break down some things to look for while you’re on the water.
What is a Fly Hatch?
A hatch is the emergence of aquatic insects from there nymph forms beneath the waters surface to their aerial/terrestrial adult forms out of the water. This process often leaves these flies helpless on the water and increasingly vulnerable to predation from trout and other predators such as birds.
Locating Feeding Trout During a Hatch
When exploring new or foreign trout streams, being able to locate areas where feeding fish will take advantage of hatching insects is a massive time saver. The most consistent areas I find on just about any stream, no matter the size, are tailouts. While trout may not position in these areas where deeper runs or pools shallow out and water picks up its pace, they will congregate here around the times of an insect hatch. Certainly look for these areas in the early morning and evening hours when hatches are more likely to occur.
Smooth runs will also congregate trout during a hatch. Where the current is not too fast, too slow, or too deep, trout will key in on shorelines where water slows slightly or along seams where the current can bring more insects their direction. I find trout to be a touch more selective and spooky in these areas, but there are certainly always exceptions.
On skinnier streams, the heads of a run where riffles begin to flatten give trout first dibs on disoriented flies trying to make their way to the surface. The quicker water in these areas gives selective trout less time to examine your life, often leading them to make a mistake and bringing more trout to your net. These are less common, but it is not likely you will forget the experience when the stars align in your favor.
Timing Insect Hatches While Fly Fishing
Not all insects hatch at the same times throughout the year or at the same time of day, each day over a given period of time. Daily and seasonal weather patterns can effect these hatches along with water conditions for the better or worse. Some species such as midges and Blue Wing Olives prefer the cold overcast days from fall through winter, while others, like the large Hex mayflies, have stronger hatches in the summer months at night.
Many rivers throughout the west will see reoccurring hatches under ideal conditions over several days or even weeks. These hatches can be consistent enough to begin at 10am each morning and last for 30 minutes every day for a couple weeks. These hatches can be easy to take advantage of as their predictability makes matching the hatch much more simple. Local fly shops or your standard hatch chart for the river should provide ample information and fly suggestions for these situations. Outside of these circumstances is where knowledge and experience can truly pay off. Morning and evening hatches that occur from late spring through the summer months are typically extremely consistent, but the quantities and type of insects hatching can change daily. What may start as a hatch of quills or hexes may shift to caddis rather quickly. Or while both are hatching, the fish that were originally rising to the mayflies, may decide that caddis are the easier meal at these times. But how do you know when trout make this adjustment?
Reading Water During a Hatch and Trout Rise Forms
Rise forms are the manner in which trout rise to the surface in order to eat an insect. I light tip of their nose on the surface may mean they are eat fallen spinners or younger mayflies about to take flight for the first time. A very small ripple left solely from their tail fins paired with a subtle swirl means the likely ate an emerging insect on its way to, or trapped just below the surface. A splashy rise on the surface is typical when larger or more active flies are dancing on the surface. These rises are also typical during the peak of caddis hatches where gluttonous trout impatiently fill their stomachs as fast as possible.
Forming a consensus on the types of rise forms you are actively seeing on the water can be an indicator of what type of insect is hatching along with what stage they are in. To narrow down what species may be present we can simply look up for our next clue.
Identifying Mayflies, Stoneflies, and Caddis Flies
Identifying insects on the water doesn’t have to be too difficult. Knowing what bugs may be around from the season or piece of water you are fishing is a good first step. Many times during a heavy hatch these insects will come to you. When identifying them on the wing there are a few things to look for.
Caddis Flies are look thicker than other insects during a hatch but are much more noticeable from their flight pattern which is chaotic. Flying in a straight line seems nearly impossible for these bugs, as the appear drunk once they take to the sky. Rises are often very aggressive during a caddis hatch.
Mayflies will usually appear more wiry in profile with exceptions to some of the bulkier quills and hexes. Once in the air they appear more clumsy, as if they could fall to the ground or water under their own weight at anytime. Their larger, sailboat shaped wings can also be noticeable from some distance to the trained eye.
Stoneflies will have two pairs of wings which are easily distinguishable and are typically larger than caddis and mayflies. They fly in a steady pattern (straight lines) for the most part.
To learn more about these insects, check out our article on What Do Trout Eat.
Matching the Hatch
The next step is identifying the size of the flies you are seeing. If they happen to land on you, or you can catch one, this can be as simple as comparing the fly to the flies in your fly box. If you need to eyeball the size, take your best guess then size down by one size. This is a rule I made for myself after year of trial and mostly error. Many times I end up sizing down twice before receiving my desired outcome. Once you have identified which insects are hatching and their size, it is now time to select our flies.
Hatch Fly Selection
Unless you are already dialed in to a hatch like the ones we mentioned earlier, where one species is hatching at a consistent time every day, I prefer options when starting out. This means a two fly rig where I can narrow down effective flies quicker. My lead fly will typically be a higher floating, more visible fly that will allow me to track my flies better in the water. This is especially important during the low light hours. During a mayfly hatch for example, an traditional adams or parachute adams are great lead flies. For caddis, it is very tough to beat the old fashion elk hair caddis. Early on in the hatch process when insects are first coming off the water, I might replace these with late stage emergers such as the sparkle dun or x-caddis. Both of these patterns are still quite visible but can sit lower in the film with a shuck in tow.
Trailing this flies by a couple feet will be an emerger pattern that sits even lower in the water. Shuttlecocks, CDC Emergers, and CDC Caddis are excellent options as trailing flies. These patterns will keep half of the fly below the surface while the other half rides in the film. After my flies are chosen I will gauge the trout’s reaction and make adjustments accordingly.
Learn more about the best fly imitations for these scenarios in our articles on The Best Mayfly Patterns, The Best Stonefly Patterns, and The Best Caddis Fly Patterns.
Hatch Fishing Techniques
With our two fly rig ready to go I will target individual rising trout in my section of river. It is important to do this as casting in the middle of a dozen rising fish doesn’t necessarily yield better results. Trout feeding during a hatch typically like to stay in their chosen lanes, not straying far. You can’t expect a trout to stray across the current for your fly when food is so readily drifting into its face.
During a hatch, you typically do not need to lead a rising trout by much. 3’ being ideal. This length can widen in certain conditions, so tinker with this while on the water. Your lead fly should be visible at this point, your trailing emerger less so. Keep your peripherals glued to the 2 foot radius from your lead fly for any activity will help identify any eats on your emerger pattern.
Hopefully one of these patterns is the ticket. Often 2 to 3 drifts to a rising trout should be more than enough to know whether he is willing to eat your selection. If the emerger manages to land the fish, keep the rig together and continue targeting other rising trout. If the trout shows interest in the lead fly, consider removing the rear fly to avoid fouling the trout on the rear hook and to ensure your lead fly looks as clean as possible (no trailing tippet hanging out the back). I will also note, the downside to a 2 fly rig is that the flies can pull on each other, making it difficult to achieve a perfect drift in some water types.
Trout Refusals
A lackluster rise and subsequent refusal where the trout retreats back to the bottom, may be disappointing, but should be taken as a sign that you are barking up the right tree. Especially if the trout leaves a hard boil. Several missed strikes should be taken with the same regard. Usually the next move would be to downsize one or both of your flies. Unless the emerging flies you’ve begun seeing have gotten larger, smaller is more times than not, the ticket. Using this feedback from the trout and adjusting size, pattern, and where the fly is sitting in the water column, should eventually yield results. This can be a frustrating process on the water when trout are feeding everywhere around you, but incredibly rewarding once you solve the puzzle.
Hatch Transitions
On less prolific hatches, anglers may find themselves seeing the occasional rising trout with only a handful of bugs in the air. As an example, morning hatches of midges in the winter months are common in many North Carolina streams. Selective trout will feed on these flies throughout the morning in particular runs where rising fish are likely to be. As the morning progresses, these trout can transition to eating Blue Wing Olives. While some trout may eat the same flies under both circumstances, anglers can increase their productivity by changing flies. Noticing when trout make this transition is often difficult for those not paying attention to what is going on around them. These changes may be as subtle as seeing a dozen of midges flying around over a five minute period, to seeing two or three BWOs taking to the air in a similar duration. This may be accompanied by an uptick in rising fish as the BWOs make for a hardy meal. The most successful anglers know how to stay ahead of these trends and transitions. This skill set does not come immediately as experience plays a major role in the learning curve.
Another common scenario on many river is localized hatches. Hatches may not occur all along a mile stretch of river. They may instead be localized to a single run or pool on the stream. Finding these gold mines can take some luck for anglers unfamiliar with a particular river. In these cases being familiar with the seasonal hatches on a river as well as the tendencies of when the particular hatch tends to happen anglers can attempt to cover larger stretches of water on foot or in a boat in order to find the hot bite. Some pools are particularly productive on summer evenings where consistent hatches bring trout to the surface consistently each day. Once you find these pools or runs, be sure to visit during similar times and conditions.
Hopefully these tips will help limit those frustrating days on the water where the trout are clearly gorging on insects but you just cant seem to buy a bite. Be sure to follow us on Facebook or Instagram to stay up to date on our latest tips and techniques articles that will help you grow on your fly angling journey.