BirdTroutOpen the map Is the Au Sable River good for brown trout?
Yes, with a caveat. Michigan's own survey records list brown trout in the Au Sable River, and stocks it as well, and the river's measured July mean of 70.2 °F runs above the 54–66 °F this fish prefers but below the 75 °F it stops feeding at — so the cold stretches carry it and the warm ones are marginal in high summer. Across 8 gauged stretches the July mean runs 66.3–75.5 °F, so the answer changes with where you stand on it. Fish of 8–18 inches are what Michigan reports as typical. The river is designated Type 1, Type 2, Type 3 and Type 4 trout water, which is what sets the size and creel limits.
What the state's records say
- Species
- Brown trout (Salmo trutta)
- In Michigan
- introduced
- Record here
- surveyed present, and stocked
- Holds in
- 54–66 °F, stops feeding above 75 °F
- Typical
- 8–18 inches
- Spawns
- Late October into December, on gravel riffles, later in the season than the rainbow and overlapping the brook trout.
Introduced. The first brown trout planted in North American water went into the Pere Marquette in April 1884, from German eggs by way of the Northville hatchery — the river is still fished for the descendants.
Is the water cold enough
Measured, not modelled: 8 gauged stretches of this river average 70.2 °F in July (66.3–75.5 °F across them), against the 54–66 °F this fish holds in and the 75 °F it stops feeding at.
| Gauge | Now | July mean |
|---|---|---|
| Red Oak | 56.3 °F | 66.3 °F |
| Mio | 57.6 °F | 70.0 °F |
| Mc Kinley | 56.1 °F | 69.5 °F |
| Curtisville | 57.4 °F | 71.8 °F |
| South Branch | 60.4 °F | 74.0 °F |
| Glennie | 60.6 °F | 74.1 °F |
| Sidtown | 63.5 °F | 75.4 °F |
| Au Sable | 64.8 °F | 75.5 °F |
What you may keep
| Reach type | Miles | Minimum | Season |
|---|---|---|---|
| Type 1 Designated | 15.1 | 8″ | Last Saturday in April–September 30th |
| Type 2 Designated | 13.0 | 12″ | Last Saturday in April–September 30th |
| Type 4 Designated | 27.3 | 10″ | January 1st–December 31st |
| Type 3 Designated | 12.1 | 15″ | January 1st–December 31st |
From Michigan's own regulation tables, per designated type, and the current digest is the authority rather than this page. Full regulations for this river →
What to fish for it
- Fish Eggs — October–January and April, #10–16
- Little Black Stonefly — January–April, #16–18
- Little Brown Stonefly — February–April, #12–16
- Blue-Winged Olive — March–May and September–November, #16–22
- Blackfly — April–June, #18–22
- Blue Quill — April–May, #16–18
- Cranefly — April–June and September–October, #6–10
- Grannom — April–May, #14–16
The insects recorded from this river's region, earliest first. The full calendar →
More about Au Sable River
Au Sable River — live water temperature, regulations and access
- Is the Au Sable River good for brook trout?
- Is the Au Sable River good for rainbow trout?
- When to fish the Au Sable River, Michigan
- How to get to the Au Sable River, Michigan
- Au Sable River fishing report
- Au Sable River fishing regulations