Late Spring and Summer Hatches
By Al Caucci
During the exciting June period, the eastern angler
can expect heavy hatches of sulphurs (Ephemerella invaria, rotunda and dorothea)
ranging in size from #14 to #18, large isonychia mayflies, and the spectacular
hatching and spinner activity of the big green and brown drakes (Ephemera
guttulata and simulans). The midwestern angler has an abundance of both sulphur
and isonychia mayfly hatches, but is also blessed with the truly awesome hatches
of the giant Hexagenia limbata. The midwestern angler also has the prolific
activity of brown drakes (Ephemera simulans).
During this period, the water temperatures on
freestone rivers ranges between 58 degrees F. and 65 degrees F., driving the
trout to their metabolic peak. Hatching begins subtly in the mornings, and ends
with a wild, heavy burst at twilight. During the day, Stenonema Cahills,
Ephemera drakes, and Hex duns hatch sporadically. Their sparseness, together
with their large size and fumbling efforts to take flight, create sporadic
feeding activity. Trout generally are not very selective during this time, but
good presentation is necessary, especially on sunny days when trout are spooky.
Pictured left is an
Ephemerella infrequens female dun (pale morning dun if you flunked
Latin), a staple throughout the west. On the right is a blue-winged
olive male dun (pseudocloen), an active hatcher from spring through late
Sulphurs create steady, selective feeding from early
evening into dark. Trout are usually very selective during this hatch. On cloudy
days, or during inclement weather, the best activity may take place in the
afternoon. During heat waves, this action may occur in the morning, evening, and
well into dark.
June is also the time for the giant stoneflies, such
as the eastern salmon fly (Pteranarcys dorsata), the great brown stone (perla),
and the willowfly (acroneuria). Also, there are wonderfully prolific hatches of
hydropsche and glossosoma caddisflies that trigger excellent feeding activity.
Anglers must carry with them a wide variety of pattern types, not only to match
the variety of naturals, but also for the various insect stages: nymph, emerger,
pupa, dun and spinner.
At twilight, heavy spinner flights may resemble living
blizzards, causing the well fed trout to become super selective. It's not
unusual for species of mayflies and caddis to be emerging simultaneously. Trout
are selective to the species and stage of the dominate insects, and the correct
imitation is imperative for consistent success. Observation is the key. Check
the size, color, and stage of the various insects, and match them with the
The western hatches of summer begin with a crazy
flurry of mayflies, caddis and stoneflies. Super hatches, like the salmon fly,
golden stonefly, western green drake, flav, gray drake, and the hydropsyche
caddis flies, are prevalent throughout the Rockies, Sierras, and Cascades in
June and July (see "Match The Hatch" in the March/April issue for more
information on this activity-Ed.)
From mid July throughout the summer, most western
rivers are very productive, especially those rich, cold, tailwater rivers, like
the Henry's Fork of the Snake, Madison, Big Horn, Missouri (below Holter Dam),
and the Dechutes. Also great are the Clark Fork, Blackfoot, Bitterroot, and Rock
Creek, in the Missoula area of Montana, which are less influenced by cold bottom
not least, if you hail from the East or Midwest-is the everpopular
sulphur (Ephemerella dorothea).
The summertime staples on all these rich rivers are
the size 16 and 18 pale morning duns (Ephemerella infrequens and inermis),
tricos in sizes 24 to 28, tiny blue winged olives (psuedocloeon, sizes 20 to
26), and heavy hydropsyche caddis in sizes 14 to 20.
During the summer months, the western rivers continue
to produce ideal water temperatures and prolific activity, due to their
altitude, glacial influences, and innumerable springs, but in many cases it is
due to the large number of blue ribbon tailwater rivers.
Around the 4th of July, most eastern and midwestern
free stone rivers may lose over 70% of their volume, raising the water
temperatures well into the 70's, and making it difficult for both trout and
The AuSable and Pere Marquette in Michigan, and the
Namekagon in Wisconsin, are just a few rivers that fish well throughout the
summer. Wisconsin, Michigan, and the Upper Peninsula of Michigan all have many
excellent spring fed streams and rivers that produce great hatches throughout
Pennsylvania, New York, and New England have many
trout streams that are also excellent throughout the summer. Famous small
limestone streams in southeastern Pennsylvania, like Big Spring and Falling
Spring, have excellent trico hatches. The larger spring creeks of central
Pennsylvania all have superb hatches of tiny tricos and blue-winged olives, as
well as late season caddis, plus scuds and cressbugs.
The Northeast and Southeast have a number of
tailwaters that produce great summer hatches, from the Upper Delaware river
tailwaters in Pennsylvania and New York, to those southern Appalachian gems, the
Watauga and South Holston.
The Upper Delaware has two tail-waters, the East
Branch in New York and the West Branch, which forms the border between New York
and Pennsylvania. This is big, wild trout water, with over 100 miles of fishable
The crown jewel of this system is the West Branch,
which flows out of the Cannonsville reservoir. Mandatory, ice cold releases
during June, July and August keep the river in the mid-50 degree F. range all
summer long. The constant release affects the entire length of the West Branch,
and 20 miles of the main stem. Transmitters planted in over 50 wild trout
between 15- and 25-inches in length show that the wild browns and rainbows from
the lower East Branch and main stem migrate to the colder West Branch and upper
main stem when the water begins to warm up during hot spells.
The West Branch and upper main stem sustain prolific
hatches of size 24 to 28 tricos, size 20 to 28 blue-winged olives, small (size
18 to 20) sulphurs, size 14 to 16 light Cahills, and large (size 12 - 4X long)
isonychia mayflies, plus late stoneflies, hydropsyche and limnephilis caddis
flies that range from size 8-4X long to a small size 20.
The tailwater phenomenon, which became prevalent in
this country over 30 years ago, has been controversial. Yet, no one can deny
that approximately 75% of the top trout rivers in the country today are
tailwaters. So forget about the old tradition of trout fishing season being
mainly in the spring. Grab your rod, don your waders and go fishing this summer!