Ontonagon River

Michigan's biggest hatch and the last of the Au Sable's Big Five: 4-8 duns emerging in the dark from silt banks on muggy nights from about 10 pm, with spinner falls one to three nights after the first duns. Peak on the Au Sable Holy Water is June 20-28 (Mio Trophy Water is the classic Hex water), Manistee June 25-July 5, Pere Marquette June 10-25, Muskegon tailwater June 8-20, and the U.P. two to three weeks later (Superior Flies peak July 5-21). Fish a Hex dun or spinner such as Robert's Yellow Drake, McCoy's All Day Dun or a Boondoggle Hex on a short 6-foot 2X leader, and a Hex wiggle nymph or Spring Wiggler year-round; trout in prime habitat may see up to 2,000 nymphs a day outside the hatch. Watch water temperature from June 10 and expect the hatch within days once the Au Sable holds 62-65 F.

The third of the Au Sable's Big Five: short-lived, blizzard-like hatches from about 8 pm to midnight in the first half of June on the northern rivers, late May on the Pere Marquette and Muskegon. Each reach gets three to seven nights before the hatch moves upstream, so the trick is being on the right stretch. Duns emerge at dusk and the spinner fall into darkness is the best fishing; Brown Drakes and Sulphurs drive the evening rise on the South Branch. Fish a #10 Brown Drake dun or spinner, or a Robert's Yellow Drake, and a burrowing-nymph pattern over sand and silt before dark.

The small black caddis that comes off with the Hendricksons in late April and May on the Au Sable, Upper Manistee and Boardman, emerging midday and returning to lay eggs in the late afternoon and evening. Emergence is slow through the surface film, so a low-floating black emerger or a soft-hackle swung at midday usually beats a high-riding dry; in the evening a #18 black elk-hair or CDC caddis covers the egg-layers. Larvae drift heavily before the hatch and are bright yellow-orange, so a small orange or yellow larva works under an indicator. On the Muskegon the black caddis is extremely heavy from mid-May through June at dusk.

The first of the Au Sable's Big Five, starting the last week of April and peaking the first two weeks of May on the northern rivers. Duns emerge mid-afternoon (roughly 2-5 pm on the Au Sable) for one to two hours, and spinners return to the riffles late afternoon to dusk, often compressed into a half hour; cool evenings push the spinner fall to the next morning. Fish a Pheasant Tail or dark-wingcase nymph before the hatch, then an emerger or Regan's Hendrickson Parachute (#14) during it, and a rusty spinner at dusk. The male dun is the darker Red Quill, tied a size smaller.

The second of the Au Sable's Big Five and the bread-and-butter afternoon hatch of late May and June on the northern rivers, with dense hatches on the Pere Marquette that create selective risers in slow glides and tail-outs. Emergence is sporadic through the day with an afternoon-to-evening peak, and spinners drop at sunset. Trout routinely refuse duns during this hatch, so emergers and rusty spinners outfish dun patterns; carry pale yellow, orange and olive shades because body color varies. On the Muskegon and Pere Marquette the hatch runs a size smaller and continues through July.

The pale summer clinger of June through mid-August, coming off in the afternoon and evening on the Upper Manistee, Au Sable and Muskegon. Hatches are scattered rather than heavy, so the Light Cahill is often a searching pattern: a #12-14 cream parachute fished through riffles and pocket water on summer evenings. Spinners fall at dusk over the riffles. A Robert's Yellow Drake covers Cahills, Sulphurs and Brown Drakes in one Michigan pattern.

The fourth of the Au Sable's Big Five, with a June peak and a second September peak that gives some of the best fall dry-fly fishing. Nymphs are strong swimmers in fast cobble water and crawl out on rocks to emerge, leaving shucks on the stones, so a swum or stripped #10-12 Iso nymph is the primary fish-catcher, and the spinner fall in late evening over moderate current is the surface event. Fall duns often emerge midday and trout do take them on the water; a #12 Adams or Borcher's Drake covers the dun and spinner. Starts the first week of June on the Muskegon and runs sporadically to September.

The small dark mayfly that brings trout up on fall afternoons after the Tricos and before the season closes, mid-September through October on the Pere Marquette and, by the U.P. chart, into November farther north. Duns emerge in slower water and eddies during the warmest part of the day, when they overlap the fall Blue-Winged Olives; a #16-18 mahogany or rusty parachute solves the fish that refuse an olive. Fish a small dark nymph on the edges beforehand and a rusty spinner late in the afternoon. On the Upper Manistee, mahogany duns are also listed among the May-June hatches, where the Blue Quill record applies.