When it comes to calm waters, few insects matter as much in a trout’s diet as the mosquito. A true staple for trout, the mosquito hatches year-round in open water and in the north, from ice to ice in most of our still-water fisheries. There are four stages in the mosquito life cycle, these stages include the egg, larva, pupa and adult, the last three of these four stages being quite important for trout and still water fly fishermen. The second of these three stages, the larval stage, is often overlooked.
Mosquitoes come in many colors and sizes. The adult mosquito looks a lot like a mosquito, but luckily for us it lacks the mosquito’s trunk. The most obvious stage in a mosquito’s life cycle, the adult, can be seen on the surface of the water, both when it sheds its pupal shell and when it returns to lay its eggs. Although trout prefer the larval and pupal stages of the mosquito, trout may appear at this stage while the adult sheds its exalted pupal skeleton, or while it waits for its wings to dry before flying. When the adult mosquito returns to lay its eggs, the mosquito will glide across the surface of the water depositing its eggs leaving a trail behind it, which attracts the trout well enough.
The pupal stage of the mosquito, the chironomid, receives a lot of attention from both calm-water fly fishermen and stream fishermen. Although the chironomid (from the name chironomidae meaning non-biting mosquito) is actually a mosquito in any deer in its life cycle, most fly fishermen refer to the chironomid as the deer pupal mosquito. Fly fishermen focus more on this stage of the mosquito because the chironomid can be found at any depth in a calm water fishery, as it rises from the bottom of the lake very slowly until it reaches the surface where it transforms into the adult. . Because of this, chironomids give trout an easy meal throughout the entire water column, meaning anglers can fish for a pupal pattern at almost any depth in the fishery with a good chance of finding trout. It is during the heat of summer when the trout move into deeper, more comfortable waters and pupal activity slows down or when the trout begin to enter active foods larger than the chironomid may not get the consistent results one seeks.
The larval stage of the mosquito, known as the bloodworm, is not a true earthworm due to its exoskeleton and small clawed feet. Chironomid larvae will spend their time living at the bottom of a lake in mud or sediment feeding on decaying matter known as detritus. In calm waters, you will find mosquito larvae in a few different colors like green and tan, but red larvae are typical. The blood of a mosquito, like humans, is based on iron, and because most still-water bloodworms live in anoxic environments, they need a protein called hemoglobin. This hemoglobin is carried by the red blood cells and stores oxygen, which maintains the viability of its cells by keeping it alive and giving the larva a blood-red appearance when little oxygen is available.
Bloodworms are often overlooked by many anglers, but quite the opposite when it comes to feeding trout. Trout often focus on the abundance of available larvae, and because of their familiarity, they readily feed on larvae even when other forms of aquatic life are abundant. Because you can find bloodworms on or near the bottom of the lake, anglers will do well to keep their bloodworm patterns within a foot or two of whatever bottom structure they may be fishing on. The fly size you choose to represent a mosquito larva should be up to three sizes larger than the adult mosquitoes seen hatching on the surface as the length of the mosquito’s body decreases in size from larva to pupa to adult .
Fishing for a bloodworm is a lot like fishing for a pupa. For the best results, you will need an impact indicator (quick release indicators work well), a floating line, and a long leader. The length of your leader will depend on how deep you are fishing, but unlike the chironomid, the bloodworm will not stray far from the bottom, so the required depth will be a foot or two from the bottom. To find this depth, take a bell weight or hemostatic forceps and place them in your bloodworm pattern. Now lower the fly until it reaches the bottom. With your thumb and forefinger, mark where your leader is at the same level as the surface of the water and secure the impact indicator one foot below this mark. Now get your fly back and take the weight off the hood. Your indicator will now float your fly one foot off the bottom. In the mornings, when the water is cooler, the trout will be found closer to shore, and shallow water bloodworm fishing should produce fish. However, in the heat of the day, trout can go further in search of cooler, more comfortable water. Work your way into deeper water by testing different depths of 12 to 22 feet of water or more, but always keeping your fly in that section one to two feet from the bottom. Your recovery should mimic the natural, so little or no movement usually produces the best results. Slow short strips or a slow turn of the hand with long pauses are often the key to success. However, there are times when attention may be what is required to get a connection, so a couple of quick short strips with long pauses can produce the results you are looking for. Depths of twenty feet or more make a leader very long and if you’ve ever tried to pick a leader for that long, you know it’s not the easiest thing in the world. When fishing at depths of more than 20 feet, a fast sinking line may be more to your liking.
At these depths, you can fish directly under your boat without fear of scaring off the trout. When fishing with a sink line, find the depth you want to fish at using the weight of your bell. Drop your weighted fly all the way to the bottom with the tip of the rod just an inch from the surface of the water. When your fly hits the bottom, roll up a liner foot. Now take the weight off the bell and drop the fly. Hold the tip of the rod one inch from the surface of the water and remove the line with quick three-inch strips and then let the fly fall back. When the tip drops or you feel a jerk, set the hook. A lot of attention should be paid with these methods, as the shots can be very smooth. Sometimes just a slight movement of the rod tip or the sensation of weed being caught is all a fisherman can see or feel and with so little warning one must set the hook or possibly miss an opportunity.
Bloodworms are a true staple for trout at any time of the year, even when the lakes are frozen. Ignoring the bloodworm is like overlooking scuds, leeches, or your favorite chironomid pupa. On those warm, slow days when nothing seems to work, toss a mosquito larva pattern into some deep water a foot from the bottom and find out for yourself what you’ve been missing. A day without fish may save you.