FLY FISHING: Chironomids

[John Pierce]

CHIRONOMIDS & THEIR LIFECYCLE

WHAT ARE CHIRONOMIDS

• Chironomidae (informally known as chironomids, nonbiting midges, or lake flies) comprise a families of nematoceran flies with a global distribution. Many species superficially resemble mosquitoes, but they lack the wing scales and elongated mouthparts of the Culicidae. Some estimates of the species numbers suggest well over 10000 world-wide.
• Males are easily recognized by their feathery antennae, the female does not bite like mosquitoes. Adult chironomids will range in size from 2 mm to 20 mm in length.
• Adults are known by a variety of vague and inconsistent common names, largely by confusion with other insects. For example, chironomids are known as "lake flies" in parts of Canada and Wisconsin. They are called "sand flies", "muckleheads", "muffleheads", "Canadian soldiers", or "American soldiers" in various regions of the Great Lakes area. However, they are not mosquitoes of any sort, and the term "sandflies" generally refers to various species of biting flies unrelated to the Chironomidae.
• Can be found in almost any aquatic or semiaquatic habitat, including treeholes, bromeliads, rotting vegetation, soil, and in sewage and artificial containers. They are often associated with degraded or low-biodiversity ecosystems because some species have adapted to virtually anoxic conditions and are dominant in polluted waters. Some species exist in the larval stage for up to 2 years before transforming into the pupa.

LIFE CYCLE STAGE: Egg

• Female adults return en masse to the lake to deposit eggs on the surface of the water.
• Eggs are released as the female dips the tip of her abdomen in the surface film while flying low over the water.
• The eggs sink to the bottom and typically hatch into larvae in several days to two weeks.

LIFE CYCLE STAGE: Larvae

• After leaving the egg mass, the larvae is worm-like in appearance with distinct body segmentation and it burrows into the mud or construct small tubes in which they live, feed, and develop. Most live in benthic/bottom of the lake zone between 5 and 25 feet in depth.
• Larvae that live in oxygen poor or almost anoxic conditions exhibit a blood red colouration due to the presence of a haemoglobin-like fluid with the circulatory system, these are often known as "bloodworms". Their ability to capture oxygen is further increased by their making undulating movements.
• Other common larval colours are black, shades and combinations of green, brown, orange, and maroon. Chironomid larvae feed on detritus or decomposing plant material. Larvae are poor swimmers but they do leave the protection of their burrows or tubes to feed. Larvae that over-winter will often move from shallower water to deeper depths and re-establish their burrows or tubes. These migrations occur late in the fall and at that time become much more vulnerable to foraging trout.
• Larvae are important food items for aquatic insects, water beetles, newts and fish such as trout who typically root out the larvae from their benthic homes.

LIFE CYCLE STAGE: Pupae

• Once the larva is fully developed it will seal itself in the tube and transform into the pupal stage. It usually takes several weeks for the change to occur, and then the pupa cuts its way out of the old larval tube (around February in BC) and then actively swims with the aid of trapped gases under the thorax and abdomen, slowly to the surface of the water. There is no turning back once the pupae begin the ascent to the surface.
• As the pupae ascend, they become shinier or more silver-like in appearance.
• Water temperature plays a major factor in determining when and how fast the pupae travel to the surface to complete the emergence process.
• Often, large numbers of pupae will stage with a couple feet of the lake bottom as they await final development and appropriate water temperatures. This staging can last for several days and during this period, the pupae are extremely vulnerable to predation by trout or other fish species. This scenario explains one of the main reasons why we can have tremendous pupal fishing and not ever see an adult actually emerge.

LIFE CYCLE STAGE: Adults

• When the pupae reaches the surface film, a split develops in the thorax of the pupae and the adult form emerges leaving an exoskeleton. Almost immediately the winged adult flies off to nearby shoreline vegetation.
• A typical chironomid emergence would see literally thousands of pupae rising to the surface. Individual trout inhale hundreds by just swimming through the water column. Major hatches occur between 10AM and 3PM.
• Mating occurs within a day of hatching and the cycle is completed.
• Eaten by surfacing fish and insectivorous birds, such as swallows and martins, bats and flying predatory insects.
• Can be pests when emerge in large numbers.

[John Pierce]

FISHING WITH CHIRONOMID FLIES

FISHING: General

• The first major insect hatch of the year and most prolonged and prolific emergences of all the aquatic insects in lakes and streams. Hatch continues to emerge in lessor numbers right up until freeze up.
• It is the pupal ascent that attracts the attention of trout and get fly fishers excited.
• Whatever techniques you use for fishing the chironomid larva and pupa it is important to have complete control over your fly line so that strikes are not missed. It is essential to double anchor your boat (bow and stern) so that changes in wind direction will not swing you from side to side or in circles. Float tubers or pontoon boat anglers should have one anchor out the back and then use their swim fins to control unwanted sideways motion. Also, keep your rod tip close to or touching the water during the retrieve thus providing as straight a line connection between rod, fly line, leader and fly. This is the best position for detecting even the slightest of strikes.
• Chironomid hatches are usually in full swing by mid-April at lower elevations. As the season progresses, chironomid fishing addicts fish higher and higher in elevation to prolong the enjoyment of this most exciting hatch.

FISHING: Larvae Stage

• Presentations should be fished as close to the bottom of the shoals or drop-off areas (generally less than 6 meters deep) as this is their prime habitat.
• Because some species over winter in the larval stage, they are a good pattern to try in both early spring and late fall.
• Larvae are poor swimmers so imitations of them should be fished very slowly or with no movement other than wave action while suspended under a strike indicator.
• A floating fly line and varying leader lengths (3 to 7 meters) will allow effective coverage of these shallower depths. It is very important to allow the fly enough time to reach the depth zone you want to fish before beginning the retrieve.
• Weight your larval pattern or add soft putty lead to a tippet knot to get down to the bottom quicker.
• Larval patterns should be retrieved very slowly or allowed to drift in the wind. It's always good to intersperse an occasional quick pull to imitate the twitching motion.

FISHING: Pupae Stage

• SEASON:
  
  
  
  • Deep water chironomid pupal emergences often occur during the early to mid-summer months.
  • These are hatches occurring at depths of greater than about 30 feet. The full sinking line technique is very effective in these situations.
• DEPTH
  
  
  
  • Papae can hatch in very 12+ m water but the majority of hatches occur in 3-5 meters. Trout can also be very particular as to the actual depth zone that they will eat the emerging pupae.
  • For example, chironomid pupae may be emerging from water that is 18 feet deep but the trout are focussed on the pupae that are passing through the 14 to 15 foot zone of the water column. In most situations, trout prefer to eat the pupae deeper rather than higher in the water column. This is especially true in very clear lakes where fish are more vulnerable to predators such as ospreys and loons.
  • Presenting pupal patterns above or below this narrow feeding zone results in far less interest by the trout. Therefore, knowing the depth one is fishing is very important. A depth sounder is a valuable asset in this type of fishing.
  • A good rule to follow is to start presenting pupal patterns within about a foot of the lake bottom and then gradually moving higher in the water column until the right feeding depth is located. One can now see why the use of strike indicators is such an effective way to suspend pupal and larval patterns at very precise depth zones.
  • At other times trout will take the pupa just under or in the surface film. The angler will see subtle head and tail or slow bulging riseforms in this situation. Shorten your leader to approximately 4 meters, grease it well to make it float and fish a pupal pattern as close to the surface as possible.
• FLIES:
  
  
  
  • It is quite common for several species of chironomids to be emerging at the same time. This offers the trout a choice of colour and size.
  • Trout can differentiate colours and thus they will switch from one colour or species of chironomid to another during the daily emergence period. Three methods to match fly to pupae:
    
    
    
    • Watch the water to detect the changing emergence patterns to better match fly to pupal size and colour.
    • Use a small aquarium net to capture pupae and emerging adults.
    • Use a throat pump to determine what colour and size of pupae the fish are actually eating. The throat pump samples the last food items that are still in the oesophagus or throat of the fish. It's best to sample only fish longer than 12 to 14 inches in length as their oesophagus will be developed enough to accept the sampling tube.
• FISHING METHOD:
  
  
  
  • FLOATING LINE: When trout are feeding more aggressively, a floating line and long leader is a very effective way to present the chironomid pupa. This method works best in water less than about 20 feet in depth, the floating fly line acts as a long bobber. Use a leader that is approximately 25% longer than the depth being fished to ensure the fly can be retrieved through the deepest depth zones. The standard procedure for this technique is to cast out, wait for the fly to sink to within a couple of feet of the bottom and then begin a very slow hand twist retrieve. Floating line retrieving may take 10 minutes to retrieve a 20 meter long cast as pupa do not swim to the surface but rise ever so slowly. One has to use a countdown to determine where the fly is in the water column. If the fly snags up on the retrieve then reduce the amount of time the fly is allowed to sink before beginning the next retrieve. Bead-headed or weighted flies sink faster and will stay in the desired depth zone as the fly is retrieved. This technique passes the chironomid horizontally through the water column but at a very slow rate to give the trout lots of time to see it. If you do not get any strikes fishing close to the bottom then further reduce the wait time before starting to retrieve. This method allows you to cover all possible depth zones that the trout may be feeding in. The biggest mistakes made when fishing chironomids with a floating line are 1) not waiting long enough for the fly to sink, and 2) retrieving much to fast.
  • INTERMEDIATE SINKING LINE (0.5-1.5IPS) METHOD: Effective for fishing chironomid larvae and pupae. The very slow sink rate in combination with a slow hand twist retrieve will allow effective coverage of specific depth zones.
  • HIGH SINKING LINE METHOD: For deep 8+ meters use full sinking lines, cast line out only as far as the depth of water, allow the fly line to sink until straight up and down and then begin a very slow hand twist retrieve right to the surface of the lake. Trout will often take fly within 6 feet of the bottom or within 6 feet of the surface as the fish follow the fly up from the deep water. Caution, trout hit deep-water chironomid flies hard, so be prepared for the rod to be almost yanked out of your hand! Remember to keep your rod tip pointed right at the surface film so that a good strike set can be completed.

FISHING: Adult Stage

• Trout will sometimes feed on the adult either as the newly emerged or the egg laying female as it returns to the water to complete the life cycle. Females typically return to the lake in the evenings when winds are down and darkness approaches.
• Riseforms will vary from quick splashy takes to very subtle head and tail sips. Individual trout will feed in a particular direction and one can anticipate where and when it will rise next. An adult pattern can be cast and retrieved ahead of the feeding fish with surprising results.
• In most situations, individual trout will show a distinct movement or feeding pattern, which will allow you to anticipate its speed and direction of travel. Cast an adequate distance ahead of the fish with a floating adult pattern. As soon as the fly hits the water give it a couple of long fast strips so that it forms a wake on the water, then let it sit for a few seconds before repeating the fast strips.

[John Pierce]

From GRR Member Jim MacDonald @ 2021-02-03:

I attended a seminar in 2009 on Chronomid Fishing by Tom Lam. Attached are my notes of this event. GRR Members should find it interesting. You have to keep in mind that this is one man's opinion and Tom Lam is considered to be an expert in this field.

Since I fished from a Belly Boat, I had to make several changes.  It is difficult to double anchor, or, even to find space to store anchors and rope, I try to stay in a stationary spot by using my flippers in lieu of an anchor, I have used a single anchor and use fins to stop rotating..  Like Ron, I use a 10 foot 5 weight rod.  The big difference is by using a Deep Six Sinking Line.  Short leader, 4 feet and 4 pound test. mono. My favorite Lake for this type of fishing is Langford.  There is a pretty deep trough close by the Aerator, close meaning about 50 meters toward shore . When Island Outfitters maintained a "Leaderboard'', most if not  all of the large trout were from Langford and most in the 6 to !0 pound range. This setup also has success when one uses "Balanced Leeches". Same method of depth calculation using, in my case forceps attached to the hook.

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Seminar notes below and attached as pdf file.

Chironomid Fishing – Tom Lam
April 4,2009

CONTROLLED DEPTH FISHING:
* Fish about 12 inches from bottom.
* Exceptions: Bloom, dense layer of mud, or water temperature inversion, then you must fish over top of these obstructions.
* Hookset should be on the upper lip. If on the side gill plate, you are fishing 12 inches too deep. If on the tongue, or lower jaw, then you are 2 feet too deep
* Depth is more important than fly selection.

EQUIPMENT:
* Two anchors, one 12 lb, bow, the other 10lb, transom.
* Rope, not poly, to hard on hands.
* Two rods, either 4 or 5 weight.
* Floating shooting head taper. One size larger than rod weight, ie, if using 5 weight rod, line should be 6 weight. This allows the rod to load faster when making casts.
* A rod leash helps from losing rod. A Velcro wrap connected to a small diameter rope.
* One end attaches to the boat and the Velcro strap wraps around rod handle.
* A large fluorescent indicator, size 6, connected to leader with tooth pick.
* To remove tooth pick from line when playing a fish, extend rod over head and allow line to come close. Tooth pick can now be removed.
* Do not use tapered leaders. They will not hang down straight
* Leader Formula: Butt end 8 lb test, minimum 10 feet long. Mid section 6lb test, 8 feet long. Both butt section and mid section are mono filament. Purchases Trilex 8 and 6lb test from Canadian Tire.
* Tippet is fluorocarbon in 4lb, but be certain to use the appropriate xx size as diameter is important. Which in this case is 1X (010)
* The leader makeup consists of a loop attachment to the fly line, a Perfection Loop is preferred. This knot allows the line and leader to slide easily through the guides. The mid section is affixed to the butt section with a triple Surgeons Knot. Connection of the mid section to the tippet is by means of a swivel. The swivel is connected to both ends using a Duncan Loop Knot. These loops should be no longer than 1⁄2 inch. The fly can now be attached to the tippet using another Duncan Loop. These loops and swivels allow the fly to hang straight down in the water.
* Leader length, Butt section is the only variable; it must be no shorter than 10 ft, however shortening may be required when fishing in depths of 19 feet, and no longer than 14 ft. This allows the greatest opportunities for fishing in water depths of 19 feet or water. When fishing in 24 to 26 feet of water, add an additional foot of line on the butt per one foot increase in depth. Nineteen feet to 26 feet of depth are the parameters for fishing Chironomids, with 24 to 26 feet being the most productive depths.
* The mid section is maintained at 8ft and the tippet at 4ft long. After changing flies and the tippet is less than 2 ft long, it is time to renew the 4 ft tippet section.
* Leader must be kept straight. Weights include wrapping fly using 0.010 lead wire, bead heads and slim tied flies.. The swivels used in connecting leaders come in three sizes. Color of swivels, gun metal grey, and are available at Canadian Tire manufactured by Mustad and weigh 3.3 grains, yes quite small.
* Reels should be wide arboured with a minimum of 100 yards of backing. Cut fly line to attain this measurement.

FISHING LOCATION:
* Look for an area with a drop off.
* Before anchoring, row a 60 foot diameter of location of area you are interested in fishing. Observe the bottom of the fishing zone using a depth sounder. This information not only gives a definition to the topography, but also can provide indicators of the bottom, i.e.. Muddy, height of vegetation and perhaps indicates a temperature inversion. Best depths are 20 to 24 feet.
* Anchor and turn off sounder. Fish with appropriate length of leader.
* If no activity, be prepared to move to a deeper or shallower area.
* The maximum casting distance should be no greater than 25 feet. This is why the rod is loaded quickly using a heavier shooting line.
* When fishing a new lake, it takes at least one week to understand the lifecycle of fish and habitat.
* A typical rod used for Chironomids can be obtained from Phil Vanderploeg. It is a Trailmaster III manufactured by Eagle Claw and comes with a wide arboured reel. It cost $100.00 US. Phone: 1 360 354 3460, or philv@toysand joys.com

FLIES:
* On bright sunny days, use a dark colored fly. It's all about contrast.
* To determine color of Chironomid, using a stomach pump; make sure those being checked are alive. Dead ones coloration deteriorates quickly. To confirm coloration, it is helpful if you can look up through the bottom of the glass container.
*A bomber is a size 10 to 12.
*Bead head should be 1/6 size of body: 5/64 bead, size 16 hook; 3/32 bead, size 14 hook; 1/8 bead, size 14 hook.
* Preferred hook is a Daiicha Hook 2312, or 1260 in size 16. A straight hook is preferred over curved variety as it is easier to taper. Pinch Barb. An inexpensive source for Daiicha Hooks and Beads is; Canadian Llama Company.
* Gills are made from white polypropylene, cut short.
* Bead is inserted onto the hook with the large diameter hole close to the eye. Make sure there is sufficient room left for the tippet to go through.
* Body requires 8 to 9 segments. Segments are tighter at the bottom and increase in separation towards the eye of the hook.
* Collar, red to Brown thread wrapped behind bead
*Body is tied, in the case of a Chromie, very thin and tapered towards the head. It is important that after tying in the body wrap and the copper wire used for segmentation, that the thread skips over this area to maintain a slim taper. The thread, in this case black, is wound up and down the hook to obtain a good taper.
* The thread of choice is Ultra thread in 70 denier size. It can be untwisted by spinning in an anti clockwise direction to flatten out and allow a flatter and smoother transition. The thickness of the build up is dependant on the next layer of body material, in this case anti static bags sliced to 1/32 strips.
* Coat the thread lightly with "Hard as Nails" to allow the anti static strip to adhere to the thread body.
* When the fly is complete, coat the whole body with "lock tite" to fix rib and body. Two coats required.