Hendrickson
Ephemerella subvaria
- Peak week
- Apr 25 – May 15
- Intensity
- Heavy
- Time of day
- Afternoon
- Water temp
- 50–58°F · peak 55°F
Top flies
Hendrickson Parachute #12-14 · Red Quill Spinner #12-14 · Pheasant Tail Nymph #14
Hatch calendar
Historic Pocono freestone with deep ties to American fly fishing tradition. Classic Eastern hatch sequence from Hendricksons through Sulphurs into late-season Isonychia.
Fishing regulations change every season. This page is a summary maintained by Bield — bag limits, exact dates, and species-specific rules must be verified with TCO Fly Shop (Bryn Mawr / State College) before each trip.
What's hatching now
Ephemerella subvaria
Top flies
Hendrickson Parachute #12-14 · Red Quill Spinner #12-14 · Pheasant Tail Nymph #14
Ephemerella dorothea / invaria
Top flies
Sulphur Parachute #16-18 · Sulphur Comparadun #16-18 · Sulphur Sparkle Dun #16
Chironomidae spp.
Top flies
Griffith's Gnat #20-24 · Zebra Midge #20-22 · WD-40 #20
Baetis spp.
Top flies
Parachute BWO #18-20 · CDC Comparadun #18-20 · Pheasant Tail Nymph #18
Spring emergence
Epeorus pleuralis
Top flies
Quill Gordon Dry #12-14 · Quill Gordon Wet #12 · Pheasant Tail Nymph #14
Brachycentrus spp.
Top flies
Elk Hair Caddis #14-16 · Henryville Special #14-16 · LaFontaine Sparkle Pupa #14
Maccaffertium vicarium
Top flies
March Brown Parachute #10-12 · Grey Fox Comparadun #12 · March Brown Nymph #12
Stenacron / Leucrocuta spp.
Top flies
Light Cahill Parachute #14-16 · Cahill Comparadun #14 · Light Cahill Spinner #14
Ephemera guttulata
Top flies
Green Drake Parachute #8-10 · Coffin Fly Spinner #10 · Green Drake Comparadun #10
Sporadic but present
Full year calendar
Each row is a hatch species. Bar color = type, opacity = intensity, peak month outlined. The current month is highlighted on the timeline.
Hatch species on Brodhead Creek
Chironomidae spp.
Water-temperature trigger
Top fly patterns
Year-round food source — the only consistent option on tailwaters in winter. On cold sunny days look for noses sipping clusters in slow water.
Capnia / Allocapnia
Water-temperature trigger
Top fly patterns
Cold-water freestone stonefly, often seen crawling on snow banks. Trout key on the nymphs more than adults.
Baetis spp.
Water-temperature trigger
Top fly patterns
Most reliable Eastern hatch. Two emergences — spring (March-April) and fall (September-October). Best on overcast, drizzly days.
Epeorus pleuralis
Water-temperature trigger
Top fly patterns
Classic Catskill spring hatch. First major mayfly of the year on many freestone streams. Emerges underwater — wet flies often outperform dries.
Ephemerella subvaria
Water-temperature trigger
Top fly patterns
First substantial mayfly hatch on most Eastern rivers. Spinner falls in evening can be as productive as the dun emergence.
Brachycentrus spp.
Water-temperature trigger
Top fly patterns
First major caddis emergence of the year. Look for clouds of small dark caddis above riffles in late afternoon.
Maccaffertium vicarium
Water-temperature trigger
Top fly patterns
Sporadic emergence rather than a heavy hatch — but trout key on individual large duns drifting through. Freestone-river specialty.
Ephemera guttulata
Water-temperature trigger
Top fly patterns
Brief but legendary. The biggest fish in the river will eat these — even fish that never rise to anything else. Penns Creek is the most famous Green Drake river in the East.
Ephemerella dorothea / invaria
Water-temperature trigger
Top fly patterns
The most important mayfly hatch on Eastern rivers. Reliable emergence + spinner fall every evening for 4-6 weeks. Match the spinners with rusty-bodied patterns.
Stenacron / Leucrocuta spp.
Water-temperature trigger
Top fly patterns
Pale yellow-cream mayfly. Less intense hatch than Sulphur but reliable across many Eastern rivers in late spring through early summer.
Isoperla spp.
Water-temperature trigger
Top fly patterns
Common on freestone rivers. Adults flutter back to lay eggs on warm afternoons — trout target the egg-laying females.
Hydropsyche spp.
Water-temperature trigger
Top fly patterns
Workhorse summer caddis. Heavy emergences and egg-laying flights at dusk through summer. Drop a soft hackle on the swing during the evening.
Isonychia bicolor
Water-temperature trigger
Top fly patterns
Long-running hatch from June into October. Nymphs are strong swimmers and crawl out of the water to emerge — fish a swung wet fly through riffles.
(beetles, ants, hoppers)
Water-temperature trigger
Top fly patterns
Not a hatch but the most important summer trout food in many Eastern systems. Fish tight to grassy banks and overhanging trees. Hopper-dropper rigs are deadly July through September.
Pycnopsyche spp.
Water-temperature trigger
Top fly patterns
Large orange-bodied caddis. The big fall food source on cold freestone rivers. Trout eat them all day in October but the egg-laying flight at dusk is the most explosive feeding.
River info
Sources
Data quality: estimated
Bield Fish reads USGS gauges, watches for the trigger window, and pings you when Brodhead Creek hits the temperature for your target hatch.
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