The fertile waters of the Missouri River tailwater near Craig are famous for prolific hatches throughout the season. The river is often described as a "giant spring creek". Blanket hatches are frequent and bring pods of fishing to the surface to eagerly intercept aquatic insects. Match the hatch fising on the Missouri is a technical game that values quality of quantity.
Blue Winged Olives (BWOs)
These small mayflies are the first major hatch of the season on the Missouri River. Beginning in late March and lasting through May and again in mid-September lasting well into October, these mayflies can hatch on any day during those two seasonal windows. Overcast days may see the strongest emergence and the Missouri River’s tailwater trout can be seen in “pods” rising to the adult mayflies. Look for pods of rising trout in softer water feeding lies—the tailouts of long flats, the inside of current seams, and slow waters near riffle corners. Sunny days can experience very strong hatches as well, but the ideal BWO day on the Missouri River is overcast, with scattered showers, and air temps in the low 50s. Spring BWOs range from size 14 to 16 and fall BWOs range in size 16 to 22.
Midges
Because the Missouri River is a tailwater fishery—its flows originating from Holter Dam near Wolf Creek—an understanding of midges is important. These insects range in size from 16 to 22, with most midges on the Missouri River being size 18 or 20. Even though these insects are small, on the Missouri River they make up a huge portion of a trout’s diet. A trout on the Missouri River may consume several thousand midges in a feeding span versus a few hundred mayflies. Midges can hatch year-round and trout feed on midges subsurface throughout the year. Any subsurface tandem nymph rig on the Missouri River should always include a pattern that imitates a midge, such as a Zebra Midge, WD-40, Love Bug, or RS2.
Western March Browns
March Brown hatches on the Missouri River can be very sporadic. They can hatch on the entire length of the river from Holter Dam to Cascade beginning in late April and can last throughout May. Conditions must be ideal—overcast, water temperatures between 44 and 48 degrees F, and very light winds. If these conditions on the Missouri River occur, a large emergence of March Browns can happen, making these large mayflies easy pickings for hungry trout. March Browns on the Missouri River range in size from 12 to 16, with most being size 14.
Skwala stoneflies
An under-achieving hatch on the Missouri River, the emergence of skwalas may feel more like legend than fact, but these size 8 to 12 insects are not to be fully ignored. On the Missouri River skwalas emerge in random fits and spurts as flying adults are rarely seen. Unlike salmonfly and golden stonefly hatches on well-known freestones where hundreds of adults can be seen fluttering in the air, a skwala emergence is subtle with only a few adults spotted airborne. But because these large insects hatch in March and April, opportunistic trout may rise to a well-presented dry fly. Most adults are size 8 or 10. Skwala nymphs are active year-round and can be immitated with a any small and dark stonefly mymph pattern.
Caddis
The Missouri River near Wolf Creek and Craig is known as a dry fly fishery. Caddis make up a majority of the hatches on the Missouri River and anglers—both dry fly and nymph anglers—flock to this central Montana river in droves to chase the well-known caddis hatches. Caddis on the Missouri River hatch from late April through August, with the strongest hatches occurring in May, June, and early July. The Missouri River is home to a large amount of caddis species. Attempting to name them all would be cumbersome and not necessary for catching more fish. Caddis nymphs on the Missouri River are active year-round and range from size 10 to 22. In late summer, evening caddis hatches provide die-hard anglers an enjoyable way to spend an evening.
Yellow Sally stoneflies
While not a major source of surface feeding action for Missouri River trout, this small stonefly does hatch in abundance in the canyon section of the Missouri River—the water from Stickney Creek access downstream to Prewett Creek access. Yellow Sally stonefly nymphs become active in early June, with adult insects hatching from early-June well into July. Yellow Sally nymphs range in size from 8 to 16, with size 10 and 12 being the most common. Because adult Yellow Sallies have very sporadic flying habits, trout rarely key on them making fishing dry flies difficult, but the nymphs are consumed on a daily basis.
Brown and Green Drakes
Drakes, both brown and green, hatch on the Missouri River. Most emergences occur in June and are sporadic. Drake hatches on the Missouri River vary from year to year, with some years seeing a strong emergence and other years anglers are found scratching their heads. These large mayflies hatch when the water temperature hovers around 55 degrees F. Brown drakes begin to be active around 50 degrees, but it isn’t until 55 or 56 degrees F that enough adults hatch on the Missouri River to entice trout to rise. Most adults are size 14, with a few sizes 12 and 16 spotted on occasion. Because they are sporadic on the Missouri River, hatches can occur from Holter Damn down to Cascade.
Pale Morning Duns
Similar to the aura around the Missouri River caddis hatches, Pale Morning Duns (PMDs) bring out the crowds. Hatching mostly from riffles and swifter water making the skill of getting a perfect drift with a dry fly a little easier, PMDs on the Missouri River are the most user-friendly hatch. These summer-time mayflies hatch in abundance on the Missouri River. PMDs begin to hatch in mid-June and last all through July. Primarily found in the river’s riffles and longer runs, PMDs emerge when water temperatures hit 58 degrees F. PMDs hatch on sunny or overcast days on the Missouri River and they can hatch in either condition. Nymphs are available to trout year-round, but during a hatch, the hatching insects require time to allow for their wings to dry before taking flight, therefore easily available to a sipping trout. Most PMDs are size 14 and 16, with size 16 being the most common.
Trico mayflies
Small in size, emerging in the early morning hours, and seen only for a few weeks of the angling season, trico mayflies have a dedicated following of anglers on the Missouri River. If Pale Morning Dun mayflies are the mayfly hatch meant for all abilities, trico hatches are best suited for experienced anglers. Tricos offer something for anglers desiring small fly, technical dry fly fishing. Tricos usually hatch at sunrise in late July and throughout August. An emergence rarely lasts longer than a few hours. Adult tricos swarm in mating swirls above the water, after mating they fall to the water and die, creating “spent” mayflies, also called “spinners” by many anglers. Most adult tricos are size 18 to 22.
Terrestrials: Grasshoppers, ants, and beetles
As the heat of summer grows and hatches become more sporadic and less predictable, trout look to land-based insects for food. Grasshoppers, ants, and beetles dominate a trout’s diet by late July. Having been blown into the river these land-dwelling insects are a common occurrence on the Missouri River. Once on the water they become easy prey for hungry trout. Most grasshoppers are sizes 8 to 12 and most ants and beetles are size 14 to 18. Colorations vary but natural tones like gray and tan tend to fish better than bright colors.
October caddis
Compared to other rivers in Montana, the Missouri River has the most reliable hatches of October caddis. October caddis can hatch as early as late September and will typically peak in mid-October. Despite the Missouri River having an abundant population of October caddis, an emergence of October caddis is limited to a few flying insects in a given section of the river. But an opportunistic trout may feast on one of these large caddis species if it happens to float by at that same time a fish feels hungry. Most October caddis are size 8 to 10.