Post-Spawn Trout Tactics: Fishing the PMD and Caddis Hatches in May and June

The spring spawn is over, the water is dropping clear, and trout are hungry. May and June mark one of the most productive transitions in fly fishing — post-spawn trout shift from the shallow, distracted behavior of the spawn into focused, opportunistic feeding driven by the year's most important hatches. The Pale Morning Dun (PMD) and caddis emergences define this period, and understanding how to fish them puts you onto rising fish on some of the best dry fly water of the year.

The Behavior Shift After the Spawn

Rainbow trout spawn in late winter through early spring. By May, most have recovered and are back in their feeding lies, aggressively building energy reserves. Brown trout, which spawn in fall, are by May fully recovered from a hard winter and actively feeding through the warming days. Either way, by late May your trout are opportunistic, positioned for efficiency, and willing to rise.

The biggest behavioral change to understand: post-spawn trout stop relating to spawning flats and redds. They're back in feeding lies — the heads of pools, current seams at the inside edge of bends, slow water behind boulders, and long shallow riffles where food concentrates. Find the food drift and you find the fish.

The PMD Hatch: What It Is and Why It Matters

The Pale Morning Dun (Ephemerella species) is arguably the most important late-spring and summer mayfly hatch on Western tailwaters and many freestone streams. PMDs typically begin in late May and peak through June, often extending into September on cold tailwaters. They're size 14–18 with a pale yellow-olive body, and they emerge during mid-morning to early afternoon — which makes them ideal for sight fishing to rising trout.

What makes PMD fishing complex — and rewarding — is that the hatch happens in stages, and trout can key on any of them:

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• Nymph (pre-hatch): PMD nymphs move actively in the water column for hours before emergence, rising from the bottom to the surface repeatedly in what entomologists call "pulses of benthic drift." This creates outstanding nymph fishing even before you see a single fish rise.
• Emerger: As nymphs attempt to shed their shucks at the film, they become trapped and vulnerable. This is often when the best fish are feeding — lazily sipping cripples and emergers just below the surface while ignoring perfectly presented duns on top.
• Dun (adult): Once the duns are riding the surface in numbers, trout begin rising confidently. Fish the tails of pools and long glassy runs where duns pile up.
• Spinner: After mating, female PMDs return to the water to lay eggs and die flat on the surface with their wings outstretched. Spinner falls often occur at dusk and can trigger the heaviest surface feeding of the day.

Reading the rise form tells you which stage the trout are eating. A nose breaking the surface cleanly means they're taking duns. A subtle bulge or ring with no splash usually means emergers or nymphs below the film. Adjust your fly accordingly.

Key PMD Fly Patterns

• Nymph: Beadhead Flashback Pheasant Tail (size 16–18), Barr's Emerger, or a generic PMD nymph fished on a dead drift near the bottom
• Emerger: Sparkle Dun, CDC Emerger, or a soft hackle Pheasant Tail fished in the film — this pattern is consistently overlooked and often outperforms everything else during active emergence
• Dun: Parachute PMD (size 14–18) in pale yellow — the parachute post makes it visible on riffled water and keeps the fly riding naturally
• Spinner: PMD Spinner with rust or spent wings, fished flat on the surface at dusk

Track which PMD patterns are working on your water each season in Bushwhack — hatch timing and most-effective patterns vary enough by river and year that your own notes become more useful than any published hatch chart.

The Caddis Hatch: Motion and Aggression

Running alongside the PMD hatch — and sometimes outcompeting it for trout attention — is the spring caddis emergence. Brachycentrus (Mother's Day Caddis) and related species produce some of the most visually exciting surface feeding of the year. Unlike the delicate, slow-drifting PMD dun, caddis pupae rocket to the surface during emergence, creating explosive, leaping rises as trout chase them. You'll know you're in a caddis hatch when trout start launching out of the water.

Caddis fishing requires a different approach:

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• During emergence: Fish a soft hackle or wet fly (size 14–16) on a tight-line swing through fast riffles. The swinging motion mimics the ascending pupa perfectly and triggers savage strikes.
• Adults on the surface: An Elk Hair Caddis or X-Caddis dead-drifted or given a slight drag (caddis adults skitter) is the go-to dry. Trout will often chase a dragging caddis when they refuse a motionless PMD.
• Evening egg-laying: Female caddis return to the surface to lay eggs at dusk, often causing the evening's biggest surface activity. A size 14–16 Parachute Caddis or Hemingway Caddis works well during this phase.

Tactics for Reading Post-Spawn Trout Water

May and June conditions demand a fresh read of the river. Runoff from snowmelt may still be pushing flows higher and slightly off-color in early May on Western rivers, clearing through the month. As water drops and clears:

• Move to the edges: High, fast water pushes trout to the margins — softer water near the banks, slower inside bends, and eddies behind mid-river boulders
• Fish the seams: The transition line between fast and slow current is where food concentrates and where post-spawn trout hold most efficiently
• Shallow riffles matter: Don't overlook broken water 12–18 inches deep. PMD nymphs are heavily concentrated in riffles, and post-spawn trout actively feed in surprisingly thin water during a good hatch
• Look upstream for risers: Position yourself downstream of rising fish, move slowly, and present your fly before you present your shadow or fly line

Leader and Tippet for Late Spring Hatches

As water clears after runoff, trout get spooky. A 9-foot leader tapered to 5X is the baseline for PMDs and caddis, with 6X tippet often necessary on flat, clear water for smaller flies. Use fluorocarbon tippet for nymphs and emergers fished below the film, and copolymer or nylon for dry flies where the stiffer knot at the fly can affect the float. Small details matter in clear June water.

The Best Weeks of the Year Are Right Now

The PMD and caddis hatch overlap period in late May through June is when many Western fly anglers consider the season to be at its absolute best. Post-spawn trout are fat and aggressive, hatches are consistent, and fish are rising throughout the day rather than just at dawn and dusk. Get on the water before the heat of summer concentrates fishing pressure into the early mornings, and bring both your nymph and dry fly setups. You'll use both before the day is out.