If there were only two months that I could be out on a stillwater fishery, they would have to be June while the chironomids are presenting themselves throughout the water column in huge numbers and then again in September. Staples office supplies has focused a lot of their advertising around this time of year with a Chistmas jingle... "it's the most wonderful time of the year". Of course they are referring to our kids going back to school but I like to think more along the lines of waterboatman and backswimmers. These air breathing insects are maturing now and becoming more active as they start their migration/mating flights and the trout are starting to key in on them in a big way.
Waterboatman Mottled Shellback
Boatman & backswimmers both need to surface for air. They trap a bubble of air once they've surfaced and head back down into the water. Boatman are the smaller of the two with a tan or masking tape colored underside and a dark mottled shell back or wing case. A mature boatman usually doesn't get any bigger than a size 12 and patterns using a size 14 hook would be typical. Water boatman feed under the surface on plant life like algae although some species are carnivorous. Backswimmers are the larger of the two and have a dark underside with a light, often cream colored wing case with darker markings. Backswimmers typically hang upside down in the surface film when looking for prey and when it finds it, with lightening speed will attack, then using it's piercing mouth parts, it will suck the juices of it's victim. Backswimmers will feed on water boatman, snails and other aquatic life forms but be careful, those that incorrectly handle a backswimmer could get a nasty bite similar to that of a bee sting. Mature backswimmer patterns can be tied up to size 8 but sizes 10 & 12 are typical. Propulsion of both species come from large oar like legs and are the key ingredient in pattern imitation.
Waterboatman Underside
The observant fly angler will notice these insects constantly rising to the surface then heading back down. As they use their long legs to descend, an erratic motion will also be seen caused by the boatman or backswimmer fighting the needed air bubble that wants to bob the insect back up to the surface. Using floating patterns and an erratic retrieve does an excellent job at imitating how the naturals move under the surface. Sinking lines and especially tradition sink lines will have your patterns working in a "U" shape as your patterns are stripped in. Most takes will come when the flies are ascending to the surface as trout will follow them up. Stopping your retrieve and hanging your flies near the surface will often be productive. On a day that triggers a mass migration/mating flight (usually a very cool night followed by a warm, sunny, autumn day), you may see what looks like little rain drops. These are the boatman/backswimmers falling from the sky. If there is enough boatman & backswimmers hitting the water, it will cause a trout feeding frenzy where the trout will stay near to the surface attacking rain drop after rain drop. The fishing on these days can be unforgettable and simply casting into or near a rise ring will bring instant success. Both waterboatman & backswimmers can dive down to 30ft or more to deposit eggs but shallower water will hold more of these insects. Try depths of 15ft or less.
If you would like to learn about stillwater fly fishing, book a clinic with me and experience how great this time of year can be. For more information on my stillwater clinics or casting lessons, visit my stillwater site at www.albertastillwaters.com.
Here are some patterns that have worked well for me, tie up some for yourself and go out and enjoy... "the most wonderful time of the year".
Tying the ultimate boatman using white body foam and coloring up the top with a dark marker while mottling the bottom of the fly makes a great backswimmer pattern as well.
