Sulphur Hatch in Michigan

Mid-May into June emergence on the AuSable, Pere Marquette, and Manistee. Ephemerella dorothea and inermis timing and tactics.

Sulphurs are the bridge hatch between hendricksons and hex on Michigan rivers, running from mid-May into June with reliable evening emergence. Chris Izworski covers identification, timing, and the fly choices that match the small yellow mayflies.

Sulphur species in Michigan

Two sulphur species dominate Michigan rivers: Ephemerella dorothea (the pale evening dun, size 16 to 18) and Ephemerella inermis (the slightly larger sulphur, size 14 to 16). Both have pale yellow-cream bodies, light dun-colored wings, and three tails. The duns hatch in late afternoon and evening, and spinners fall at dusk. On any given evening in late May or early June, you may see both species in the air at once, with duns hatching from the riffles while spinners drop into the flats.

Sulphur nymphs are small dark olive swimmers that live in gravel and weed beds. Pre-hatch nymph fishing is productive in the late afternoon before the surface emergence kicks in. The hatch itself is usually concentrated into a 90-minute window between 7:30 PM and 9:30 PM during the peak of the run.

When sulphurs emerge

Sulphurs begin in mid-May on the AuSable mainstem, overlapping the back half of the hendrickson hatch. Peak sulphur fishing on the AuSable is typically the last week of May into the first ten days of June. On the Pere Marquette, sulphurs run roughly the same calendar. On the lower Manistee below Tippy Dam, the hatch can extend into mid-June.

Daily emergence is evening-focused. On cool days, sulphurs may start as early as 6:00 PM. On warm days they delay until 8:00 PM or later. The duns hatch for about 45 minutes, then the spinner fall begins, often overlapping with the tail end of the emergence. Both stages are eaten. The trout key on whichever stage is most abundant at any given moment, so observation matters.

Sulphur patterns

Carry a parachute sulphur in size 16 (cream body, pale dun post) for the dun stage. A comparadun sulphur works on flat water where a parachute creates too much footprint. For the spinner stage, carry a Rusty Spinner in size 16 with a slightly more yellow tint than the hendrickson spinner. A small yellow emerger pattern in size 16 (low-riding, partially submerged) is critical for fish that are eating in the film rather than fully on the surface.

Watch the rise forms. A clean splashy rise usually means a fish is taking a dun on the surface. A subtle sip or quiet swirl usually means an emerger or spinner. The fly should match what the fish is actually eating, which is often not what is most visible to you. Many anglers throw duns into a spinner fall and wonder why they get refusals. The clear key is to look at the water, identify what is hatching versus what is dying, and tie on accordingly.

Sulphur water on Michigan rivers

The AuSable Holy Water and the South Branch fly-only water both produce excellent sulphur hatches. The South Branch in particular, with its slower flats and gravel-bottomed riffles, holds large numbers of wild brook and brown trout that key on sulphurs heavily. The North Branch from Lovells downstream is good sulphur water with smaller fish.

The Pere Marquette flies-only section is dense sulphur water in late May and early June. The lower Manistee from Tippy Dam down to the Bear Creek confluence holds sulphurs through mid-June. The Pigeon River, the upper Sturgeon, and the Black River in the UP all produce sulphur hatches, with the timing shifted a week or two later in the cooler UP water.