Michigan Flies

Fish

Brook trout

Salvelinus fontinalis

Michigan's native state fish, the brook trout is the headwater and Upper Peninsula trout, found in any stream that runs clear and cold and in the Black River system of the northeast Lower Peninsula. It is an opportunistic insect feeder, taking mayflies, stoneflies and caddis in season and turning heavily to ants, beetles and hoppers from midsummer through early fall. Stream fish run 7 to 9 inches, while the remnant coaster form of Lake Superior can reach 25 inches and 10 pounds. Brook trout spawn in October and November on groundwater gravel, and small brook trout are themselves the main prey of large Au Sable brown trout. Warming water is the species' main threat, with a movement threshold near 18 C and a lethal limit near 25 C documented in Michigan streams.

hatch matcher
Find flies for brook trout

© Bruce Deagle · CC BY · iNaturalist · Central Plateau TAS 7304, Australia · 2024

© Owen VanAntwerpen · CC BY-SA · iNaturalist · Marquette County, MI · 2026

What they eat in the river

Michigan DNR describes brook trout as voracious feeders on seasonally available mayflies, stoneflies and other aquatic insects plus terrestrials, that will also take whatever is most readily available including zooplankton, crustaceans, worms and fish. No Michigan study quantifies terrestrial share, but West Virginia stream brook trout drew 38 to 47 percent of yearly biomass and 51 to 63 percent of energy from terrestrials, which supports an ant-beetle-hopper emphasis from midsummer on.

  1. mayfly nymphs, duns and spinners, stonefly nymphs, caddis larvae, pupae and adults, midges
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    Evidence
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  2. ants and flying ants, beetles, grasshoppers, crickets, inchworms
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  3. zooplankton, scuds and other crustaceans, worms, small fish (sculpin, dace, fry)
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    Evidence
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  4. brook and brown trout eggs on small spawning streams
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    Evidence
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Runs and spawn

resident run
Widespread across the northern Lower Peninsula and especially the Upper Peninsula, where any stream that runs clear and cold is likely to hold brook trout. Fish move to headwaters and groundwater seeps in summer (movement threshold about 18 C). UP brook trout fish best August to September on rivers like the Fox; the traditional trout season runs from the last Saturday in April to September 30.
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summer run
Coaster (lake-run) brook trout begin spawning migrations into Lake Superior streams in mid-July and spawn in October and November. The Salmon Trout River in the Huron Mountains is the only south-shore stream with a significant population; restoration areas exist on the Iron, Big and Little Huron, Big Garlic, Pilgrim, Silver, Slate and Ravine rivers. Numbers are very low.
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Spawning
October, November · eggs 4.1–4.6 mm
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Egg colors: Oregon Cheese, Apricot, Peach

DNR: spawning generally occurs in October and November on gravel in spring-fed streams or groundwater seepages; up to 5,000 eggs per female. Lab work (Hokanson 1973) puts ovulation at 16 C (61 F) and below with a mid-November peak in the study population. Egg diameter of 4.1 to 4.6 mm is from a secondary source and unverified; egg color names are inferred from the general trout-egg palette, not measured.

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Coaster regulations: 18-inch minimum and one fish on the Salmon Trout River; 20-inch minimum and one fish in the 2015 coaster restoration areas (Marquette, Houghton and Baraga county streams). Elsewhere the general inland trout season and stream type rules apply; Type 1 and 2 streams close September 30.

Staple flies

Regan's Hendrickson Parachute (reference photo)Reference photo
Regan's Hendrickson Parachute
A
Dry fly#12–14Dark Hendrickson (reddish brown)Light Hendrickson (creamy tan)

The Au Sable guide standard for the first of the Big Five hatches, fished from the last week of April into mid May when water holds 50 to 55 F. Duns come off mid-afternoon (2 to 5 pm on the Au Sable) for one to two hours; drift it drag-free over riffles and tailouts. Carry both the dark male and lighter female shades in #12 and #14.

Dry fly

Reserve · $3.00
Regan's Hendrickson Spinner (reference photo)Reference photo
Regan's Hendrickson Spinner
A
Dry fly#12–14Rusty brown

Rusty spinner for the Hendrickson fall, which happens late afternoon into dusk over riffles and is often compressed into about thirty minutes. Cool evenings suppress the fall and push it to the next morning. Fish it flush in the film below riffles from late April through mid May.

Dry fly

Reserve · $3.00
Pheasant Tail Nymph (reference photo)Reference photo
Pheasant Tail Nymph
A
Nymph#10–20NaturalBeadheadFlashback

Old Au Sable Fly Shop names a #12 to #14 Pheasant Tail as the Hendrickson nymph, and it covers every Michigan Ephemerella and Baetis nymph before and during a hatch. A beadhead #10 is a standard trailer fly in U.P. steelhead rigs, and #12 to #20 versions take pink salmon in clear water. Fish it dead-drifted under an indicator or on a tight line in the weeks before each mayfly hatch.

Indicator nymphing · Euro / tight-line nymphing

Reserve · $2.75
Sulphur Emerger (reference photo)Reference photo
Sulphur Emerger
A
Emerger#14–20Yellow-orange with brown Z-Lon shuckCreamy yellow with pheasant tail shuck

Michigan Sulphurs emerge slowly through the film and trout often refuse duns, so emergers with a trailing shuck outfish the dry from mid May through July on the Au Sable, Pere Marquette and Muskegon. Fish it low in the film during the afternoon and evening emergence in 52 to 60 F water; size #16 for invaria and #18 to #20 for dorothea.

Dry fly

Reserve · $3.00
Rusty Spinner (reference photo)Reference photo
Rusty Spinner
A
Dry fly#12–20Rusty brownRust with clear wings

Supinski's Muskegon chart says 'rusty spinners at dark' for Sulphurs, and the same fly covers Hendrickson, Cahill and March Brown falls over riffles at sunset. Fish it flush in the film at dusk from May through July when you see spent wings in the foam lines.

Dry fly

Reserve · $3.00
Roberts Yellow Drake
A
Dry fly#4–18Yellow (deer-hair body)Yellow tied large for Hex

Grayling's all-purpose pale mayfly, an extended deer-hair body under a parachute post, sized #4 through #18 to cover Sulphurs, Cahills, Brown Drakes and the Hex. Hawkins names a large Roberts Yellow Drake as a Hex dun and spinner; fish it after dark in late June on a short 6 ft 2X leader. Every Au Sable shop stocks it.

Dry fly

Reserve · $3.00
Blue-Winged Olive Parachute (reference photo)Reference photo
Blue-Winged Olive Parachute
A
Dry fly#14–24Olive body, gray wingOlive-brown

Baetis hatch three broods in Michigan, with the biggest in early May, a second in late June and a third in September, and they run through winter on the Muskegon and Big Manistee tailwaters. Current Works lists BWOs #16 to #22 as year-round on the Upper Manistee. Fish it midday, especially on overcast, drizzly afternoons, and go down to #24 for the late-season Pseudocloeon on the Muskegon.

Dry fly

Reserve · $3.00
Borchers Parachute (reference photo)Reference photo
Borchers Parachute
A
Dry fly#10–16Dark turkey-quill body, brown hackle

Grayling's dark all-purpose mayfly, listed by Hawkins in #10 to #16 for Mahogany and Isonychia spinners. It doubles as a Hendrickson and Black Quill dun in spring and a fall Mahogany Dun on the Pere Marquette from mid September through October. Fish it at dusk for Iso spinner falls from June through September.

Dry fly

Reserve · $3.00
All brook trout flies