Hatch timing / abundance
- Golden Stonefly: opens mid-June, ~2-week prolific window; 20–40 mm; cutthroat feed hard .
- Yellow Sally (small stonefly, 7–15 mm, bright yellow/lime): arrives July — squarely in the trip window .
- Emergences run early spring → summer; nymphs crawl to shore (swept-off ones = easy prey) .
- Nymph: 20–45 mm, yellow-olive→brown→black; up to 3 years sub-surface .
Imitated by
- Adults: Stimulator, Sofa Pillow, Chernobyl Ant (foam/deer-hair, drag-free drift).
- Nymphs: Montana Stonefly, Golden Stonefly Nymph, Titanic Stonefly, Girdle Bug.
Found in (waterbodies)
- Fast freestone reaches: Goat River, Moyie River, and the Elk (Fernie). for exact local timing.
Data & occurrence sources
- Stoneflies are strong water-quality indicators (they need clean, oxygenated water), so CABIN benthic samples double as a health signal; add occurrence records via GBIF (taxa per watershed) and iNaturalist, DNA-barcode IDs via BOLD. Access, licences and the FWA-segment join method are in .
Related
- Small-Stream Dry-Fly for Cutthroat — how to fish the adult.
- Mayflies / Caddisflies (Sedges) — the other big river hatches.
