While most everyone that pursues trout on the fly, prefers to catch them on a dry fly, you shouldn’t totally rely on that. Actually, you should never rely on that. This doesn’t mean that you can’t catch trout on dry flies in June. It simply means you should stick solely with that approach. You should always base choosing the fly to use based on the most plentiful and available foods the trout have to eat at a particular time and that includes the time of day.
The most plentiful food found in the Firehole River, lower Gibbons River and Madison River, which are the most likely places you should be fishing, are midges, blue-winged olives, pale morning duns, march browns, mahogany duns, little black caddis, spotted sedge caddis, white miller caddis, the big salmonflies will hatch in the Firehole canyon and Madison as well as the lower Gibbons. Little Yellow stoneflies size 14, will also hatch the last two weeks of June. Sculpin are always available for the trout to eat.
Both cream and red or blood midges, will be available and likely hatching. Blue-winged olives, mostly size 18, at first and size 16 mid June and later, will hatch on all but the worst days, at times, even when it is snowing. Pale morning duns will be a major hatch most all month and so will the March Browns, size 14, and Mahogany duns, size 18. The water needs to be near 50 degree F. for little black caddis to hatch but that often occurs in June, particular later in the month and near major springs. White miller caddis hatch starting about the middle of June. So do Spotted Sedge caddis, size 14. Sculpin are available year-round.
The basic strategy would be to fish midge larva and pupa in tandem, or Blue-winged olive nymphs in the mornings until the warmest part of the day, usually around 2:00 PM or later and switch to adult midges (dry fly) and BWO emergers and/or duns when you observe them hatching. By the way, they are not easily spotted, so you need to closely observe the water. Late in the day, say the last two hours of good light, you may want to fish a BWO spinner. You can usually spot little clouds of spinners in the air above the water. The same strategy should be used for the March Brown mayflies and Mahogany dun mayflies. Fishing a sculpin streamer in the deeper runs and pools near the bottom and near cover is also effective at times.
Fish the midge larva and pupa, size 20 or 22, in tandem with the larva the bottom fly and the pupa about 16 to 18 inches above it on the same tippet. You can fish this rig under a strike indicator but you want to keep the midge larva fly very near the bottom. You can fish the BWO nymphs individually or under a strike indicator. High sticking, Czech an/or Euro style nymphing the BWO nymphs can also be effective. If little black caddis are hatching, you should be able to see them when they are coming off the water and/or depositing their eggs. They are a hook size 18. You should fish the pupa during the hatch or emergence of the insects and the dry fly when they are depositing eggs later in the day. They will normally hatch from around noon to late afternoon and again only if the water is around 50 degrees F or higher. The white miller caddis are easy to spot being the only white or light colored fly. The Spotted sedges are brown and a little larger than the other caddis. Fish the pupa at the first part of the hatch and adults during the egg laying. You want have any trouble spotting the big salmonfly nymphs along the banks. They crawl out of the water to hatch. The big adults are very easy to see when depositing their eggs in the afternoons. Little Yellow stoneflies are also easy to identify. They will be the only yellow colored fly. Fish the nymphs up until you start seeing egg laying and then switch to the adult. Often, you may see several of the above insects hatching at the same time and it will become a matter of which one to pursue. Just try to determine what you thinks is creating the most feeding action from the trout and pursue that particular hatch.
As always, we recommend using Perfect Flies and they imitate the real insects far better than any other types or brands. You should mash the barbs down flat with forceps or pliers (easily and quickly done) as the regulations require barbless hooks. Also, remember to use non-lead sinking material (non-lead split shot or sinkant material.
By the way, we will be glad to help you plan that next trip to fish in the park. We can help you with your needed reservations, streams to fish, flies and gear needed for any given period of time. You can call us at 800 594 4726 or email us at sales@perfectflystore.com. As always, shipping within the continental United States is free.