Midge
Chironomidae spp.
Midge
- Peak week
- Year-round
- Intensity
- Heavy
- Time of day
- Midday
- Water temp
- 32–60°F · peak 40°F
Top flies
Griffith's Gnat #20-24 · Zebra Midge #20-22 · WD-40 #20
Primary winter food
Hatch calendar
West Branch Delaware River hatch calendar.
- Tailwater
- Catch and release / wild trout management
- brown trout
- rainbow trout
- wild
The legendary cold tailwater coming out of Cannonsville Reservoir — wild brown trout to 20+ inches, prolific Sulphur and Hendrickson hatches, and the brief but explosive Green Drake emergence that anchors the Delaware fishing calendar.
Verify with the agency before fishing
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 West Branch Angler before each trip.
What's hatching now
May on the water.
Blue Winged Olive
Baetis spp.
Mayfly- Peak week
- Mar 25 – Apr 25
- Intensity
- Heavy
- Time of day
- Afternoon
- Water temp
- 45–55°F · peak 50°F
Top flies
Parachute BWO #18-20 · CDC Comparadun #18-20 · Pheasant Tail Nymph #18
Spring emergence
Hendrickson
Ephemerella subvaria
Mayfly- 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
Sulphur
Ephemerella dorothea / invaria
Mayfly- Peak week
- May 25 – Jul 5
- Intensity
- Heavy
- Time of day
- Evening
- Water temp
- 55–68°F · peak 62°F
Top flies
Sulphur Parachute #16-18 · Sulphur Comparadun #16-18 · Sulphur Sparkle Dun #16
Green Drake
Ephemera guttulata
Mayfly- Peak week
- May 28 – Jun 12
- Intensity
- Heavy
- Time of day
- Evening
- Water temp
- 58–70°F · peak 65°F
Top flies
Green Drake Parachute #8-10 · Coffin Fly Spinner #10 · Green Drake Comparadun #10
The big-fish event of the year
Pale Morning Dun
Ephemerella excrucians
Mayfly- Peak week
- Jun 15 – Jul 25
- Intensity
- Heavy
- Time of day
- Morning
- Water temp
- 55–68°F · peak 60°F
Top flies
PMD Parachute #16-18 · PMD Comparadun #16 · Rusty Spinner #16-18
Morning emergence
Tan Caddis
Hydropsyche spp.
Caddis- Peak week
- Jun 1 – Sep 15
- Intensity
- Heavy
- Time of day
- Evening
- Water temp
- 58–72°F · peak 64°F
Top flies
Elk Hair Caddis #14-16 · X-Caddis #14 · LaFontaine Sparkle Pupa #14
Full year calendar
Twelve months on West Branch Delaware River.
Each row is a hatch species. Bar color = type, opacity = intensity, peak month outlined. The current month is highlighted on the timeline.
MayflyCaddisStoneflyMidgeTerrestrial· peak month outlined · intensity = bar opacity · current month highlighted
Hatch species on West Branch Delaware River
The bug calendar in detail.
Midge
Chironomidae spp.
MidgeMiddayWater-temperature trigger
30°F32–60°Fpeak 40°F80°F- Duration
- 52 weeks
- Also called
- Chironomids · Snowflies
Top fly patterns
- Griffith's Gnat #20-24
- Zebra Midge #20-22
- WD-40 #20
- Disco Midge #22
Year-round food source — the only consistent option on tailwaters in winter. On cold sunny days look for noses sipping clusters in slow water.
Blue Winged Olive
Baetis spp.
MayflyAfternoonWater-temperature trigger
30°F45–55°Fpeak 50°F80°F- Duration
- 6 weeks
- Also called
- BWO · Olive
Top fly patterns
- Parachute BWO #18-20
- CDC Comparadun #18-20
- Pheasant Tail Nymph #18
- RS2 #20
Most reliable Eastern hatch. Two emergences — spring (March-April) and fall (September-October). Best on overcast, drizzly days.
Hendrickson
Ephemerella subvaria
MayflyAfternoonWater-temperature trigger
30°F50–58°Fpeak 55°F80°F- Duration
- 3 weeks
- Also called
- Red Quill · Dark Hendrickson
Top fly patterns
- Hendrickson Parachute #12-14
- Red Quill Spinner #12-14
- Pheasant Tail Nymph #14
- Hendrickson Comparadun #14
First substantial mayfly hatch on most Eastern rivers. Spinner falls in evening can be as productive as the dun emergence.
Sulphur
Ephemerella dorothea / invaria
MayflyEveningWater-temperature trigger
30°F55–68°Fpeak 62°F80°F- Duration
- 6 weeks
- Also called
- Pale Watery · Little Yellow May
Top fly patterns
- Sulphur Parachute #16-18
- Sulphur Comparadun #16-18
- Sulphur Sparkle Dun #16
- Pheasant Tail Nymph #16
- Sulphur Spinner #18
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.
Green Drake
Ephemera guttulata
MayflyEveningWater-temperature trigger
30°F58–70°Fpeak 65°F80°F- Duration
- 2 weeks
- Also called
- Eastern Green Drake · Coffin Fly (spinner)
Top fly patterns
- Green Drake Parachute #8-10
- Coffin Fly Spinner #10
- Green Drake Comparadun #10
- Green Drake Nymph #10
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.
Light Cahill
Stenacron / Leucrocuta spp.
MayflyEveningWater-temperature trigger
30°F60–72°Fpeak 65°F80°F- Duration
- 5 weeks
- Also called
- Cahill
Top fly patterns
- Light Cahill Parachute #14-16
- Cahill Comparadun #14
- Light Cahill Spinner #14
Pale yellow-cream mayfly. Less intense hatch than Sulphur but reliable across many Eastern rivers in late spring through early summer.
Pale Morning Dun
Ephemerella excrucians
MayflyMorningWater-temperature trigger
30°F55–68°Fpeak 60°F80°F- Duration
- 6 weeks
- Also called
- PMD
Top fly patterns
- PMD Parachute #16-18
- PMD Comparadun #16
- Rusty Spinner #16-18
- Pheasant Tail #16
More reliable on tailwaters where stable temps suit the hatch. Often runs concurrently with Sulphurs but emerges in morning rather than evening.
Tan Caddis
Hydropsyche spp.
CaddisEveningWater-temperature trigger
30°F58–72°Fpeak 64°F80°F- Duration
- 10 weeks
- Also called
- Spotted Sedge · Cinnamon Caddis
Top fly patterns
- Elk Hair Caddis #14-16
- X-Caddis #14
- LaFontaine Sparkle Pupa #14
- Tan Caddis Soft Hackle #14
Workhorse summer caddis. Heavy emergences and egg-laying flights at dusk through summer. Drop a soft hackle on the swing during the evening.
Terrestrials
(beetles, ants, hoppers)
TerrestrialAfternoonWater-temperature trigger
30°F60–78°Fpeak 70°F80°F- Duration
- 12 weeks
- Also called
- Hoppers · Ants
Top fly patterns
- Foam Hopper #10-12
- Foam Beetle #14-16
- Para-Ant #16-18
- Chernobyl Ant #10
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.
Slate Drake
Isonychia bicolor
MayflyEveningWater-temperature trigger
30°F55–70°Fpeak 62°F80°F- Duration
- 12 weeks
- Also called
- Iso · Mahogany Dun (spinner)
Top fly patterns
- Slate Drake Parachute #12
- Iso Comparadun #12
- Mahogany Spinner #12
- Iso Nymph #12 (swimming nymph)
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.
Trico
Tricorythodes spp.
MayflyMorningWater-temperature trigger
30°F60–75°Fpeak 68°F80°F- Duration
- 8 weeks
- Also called
- White-Winged Black · Curse
Top fly patterns
- Trico Spinner #20-24
- Trico Parachute #22
- CDC Trico #22
Tiny black-bodied mayfly. The spinner fall — not the dun emergence — is the main event. Look for clouds of spinners over flat water at sunrise.
River info
- River type
- Tailwater
- Primary species
- brown_trout · rainbow_trout · wild
- Management
- Catch and release / wild trout management
- Counties
- Delaware County
- Elevation
- 1100 ft
- Access
- Boat launches at Hale Eddy and Stilesville; substantial drift-boat float fishery, limited wade access.
Live water temperature & hatch alerts.
Bield Fish reads USGS gauges, watches for the trigger window, and pings you when West Branch Delaware River hits the temperature for your target hatch.
Start free trial →