Lakes Report - May 29, 2025
Welcome to the first lake report of the 2025 summer. Up in the high country, many lakes remain frozen, and others have fairly recently iced out and have yet to start cranking out the hatches. In those instances, stick with the early season program of buggers, leeches, baitfish, and other attractors and don’t overlook the near shore areas where water temps will be the warmest. Meanwhile, our low and mid elevation stillwaters iced out a bit earlier than usual this year and are now literally BUZZING with activity. If you have arrived at the lake recently and have heard what sounds like clouds of tiny drones hovering over the willows, you know exactly what I mean. Chironomids (aka buzzers or midges) have been hatching in incredible numbers on Hebgen Lake, Henry’s Lake, and beyond. While there are certainly some fish to be caught by stripping leeches or woolly buggers during non-hatch periods, the sudden appearance of literally millions of insects throughout the water column after a long cold winter has many if not most of the trout snacking heavily on one or more life phases of these diminutive dipterans. So, today’s report is dedicated to approaching a lake during periods of Chironomid activity.
Chironomids are what we call the dozens of species of insects in the order Diptera. Without going down a rabbit hole of biology, just be aware that these are insects with two wings that look more or less like a mosquito but without the nasty pointy bit at the front end. They come in a huge range of sizes from less than ¼ inch long to ¾ of an inch long or more! That’s a BIG MIDGE! Chironomids undergo a complete life cycle, with four life stages – egg, larva, pupa, and adult. Eggs are (thankfully) not relevant to fly anglers. Chironomid larvae are often referred to as blood worms, and they inhabit the muddy bottomed portions of every Stillwater in our area. Those are the zones where you need to look for the most significant chironomid activity. They are occasionally accessible to the trout when they decide to swim around a bit, perhaps out of boredom or prior to pupating. Chironomid larvae imitations can be very effective at times, and should be presented as slowly as possible, as close to the bottom as possible. For these reasons, they are often overlooked by Stillwater anglers. The process of fishing them can be rather dull.
Things change when the larvae become pupae, and begin the process of ascending towards the lake surface to hatch into the adult phase. First of all, they become much more accessible to the trout. The pupa fills with gasses and begins the often long, laborious trip up through the underwater world. They are slow, helpless, often sparkly, and always wiggly – a combination of traits that simply cannot be resisted if you are a rainbow or cutthroat trout trying to stack maximum calories after completing your spawn or a brown trout that has been feeding a bit over the winter but is now finding that its metabolism has kicked into high gear as water temperatures increase. The pupae often ascend and descend multiple times through portions of the water column before hatching, and this is the time when they are most accessible to the trout, which is why there are probably 25x more named chironomid pupa imitations than all other phases combined. The Stillwater angler has multiple options when it comes to presenting pupal imitations throughout the water column, but Step 1 is always figuring out the size, and maybe the color of the pupae that the fish want. I always look at the water surface and see if there are actual pupae wiggling around to match. If there are no pupae to see, I look for pupal shucks floating on the surface, and use those to estimate the size of the flies I tie on. When in doubt, tie on a black pupal imitation in the size matching the shucks you see. If there are multiple sizes present, that is a great time to tie on a couple of different flies or split up the work between your angling partners to solve the puzzle more quickly. Don’t have three people all starting with the same size and color chironomids!
Regardless of the presentation technique you choose, the most critical aspect is getting your flies down to, and keeping your flies at, the depth where the most trout are actively feeding on the pupae. That can be anywhere from a few inches above the bottom to a couple of inches below the surface, and might be happening in water anywhere from only a couple of feet deep to well over 20 feet deep! How do you figure it out? I use a combination of past knowledge, visual observations, trial and error, and electronics (if available) to hone in on a depth. And remember, the depth of the “hot zone” may change during the course of a day’s fishing as insect activity, wind, sun, and other factors change. If you stop catching fish, it’s worth changing your presentation depth before giving up and moving spots.
The most common chironomid presentation technique is hanging one or more imitations under a bobber strike indicator. This might seem “boring” or “easy” to the uninitiated, but I promise you there are many nuances to the technique that can entertain the mind and make the difference between catching a couple of fish or a pile of them. When the bobber twitches, slides, or drains, SET! Another super fun presentation technique utilizes so called midge tip or intermediate sinking tip lines of various sink rates and lengths paired with leaders of various length and a very slow, methodical hand twist retrieve with lots of pauses. Takes may be very subtle, requiring extreme attentiveness to visual clues such as the slight straightening of waves in your flyline, or they may be savage, tippet snapping yanks. Other useful approaches include dry/dropper rigs, and other less common tactics like the Washing Line and Vertical Hang methods (Hey, Google!). Again, it’s all about getting the flies into the main feeding zone and keeping them there. And remember, chironomid pupae are poor swimmers and move vertically more than horizontally, so slow down that retrieve!
When the pupae finally make it to the surface, they pause there just long enough for their exoskeleton to split and the adult insect to hatch out, dry its wings, and buzz off. This pause is another point in their life cycles when chironomids are helpless and very accessible to hungry trout. When the winds are calm and the weather is warm and overcast, you may find one of our local stillwaters boiling with surface activity as the trout greedily target chironomids as the emerge from their pupal shucks. This is the first gulper fishing of the year, and presenting a floating emerger pattern at or just below the water’s surface! Absolutely awesome stuff.
Adult chironomids are not as accessible to Stillwater trout as the pupae and actively emerging adults, and are therefore less relevant to the angler. That said, there are times when an adult imitation or an impressionistic pattern that might suggest a cluster of mating or spent adults could be needed. To be fully prepared to fish all phases of the chironomid life cycle, consider adding a handful of adult midge dries or general dark patterns like a Griffiths Gnat or Parachute Adams to your box.
Have fun out there, and stay tuned as we move through summer on the stillwaters.
Matt
