Everything You've Always
Wanted To Know About Blue-Winged Olives
By Al Caucci
A pseudocloeon nymph. This one originally hailed from Michigan.
Although there are good hatches
of large Isonychia (sizes 10 & 12), medium-sized Stenonema (sizes
14 & 16) and smaller size 16 Baetis mayflies in the late summer and
fall, the staple for trout during this period are the tiny blue-winged
olive Pseudocloeon (sizes 22 to 28) and Tricorythodes (sizes 26 to 28).
The tiny Trico's and Pseudo's hatch in unbelievable
numbers, and are a constant supply of food for trout on the rich spring
creeks, prolific tailwaters, and quiet stretches of rich freestone rivers.
I'll concentrate on the Pseudo's in this column, and leave the Trico's
for another issue.
The tiny blue-winged olive duns of Pseudo-cloeon
are easy to recognize in spite of their small sizes. They have no hind
wings and only two tails (Trico's have three tails) in the dun and spinner
stages. The wings are plain with no markings, and range from pale to medium
gray. The body colors range from medium olive to dark brownish olive,
according to the species.
Pseudo's are multi-brooded-most species hatching
two or three times during the course of the season. Anglers can expect
to encounter a hatch during cloudy days from June through mid September.
From mid September to November, they will also hatch on sunny days. The
nymphs hatch in a variety of water types and are slow emergers. They are
most prevalent in the alkaline spring creeks and high pH enriched tailwater
rivers. This sluggish hatching behavior, plus their prolific numbers and
long hatching periods, make them a favorite with trout-and even very large
trout. The best water temperature range for these hatches is between 48
and 55 degrees F.
Owing to their difficulty during the emergence process,
many are half drowned or crippled on the surface during the hatch. This
situation is ideal for using dun and emerger patterns with a low wing
silhouette. Color is less of a problem with these diminutive insects,
but size and silhouette are absolutely critical. Pseudo's usually hatch
in great numbers, causing fierce selectivity.
A size 24 versus a size 26, or a low-wing silhouette
versus an upright wing, will often mean the difference between a take
or a refusal. Always carry the complete size range of patterns for this
hatch, and catch a natural to confirm the size.
It's amazing how different an imitation can look
when compared to the real insect. You'll also be astonished to discover
how large the body diameter of your imitation is when compared to the
slender bodies of the delicate duns. When tying or purchasing an imitation
for a size 22 or smaller, you don't need dubbing-just a wound silk body
to keep the body slender, and a wisp of CDC or fine deerhair for the wing.
Fine tippets of 6x and 7x are a necessity when using tiny flies, as is
a drag free float. The slack-reach cast is mandatory to eliminate micro
drag when fishing this hatch.
The Pseudo spinner falls seldom occur when you expect
them-they just happen. And if you are not paying close attention to the
water surface, you won't see these insects floating by, because they have
no silhouette to mark their presence.
Many times spinners will appear during a hatch of
duns, so pay close attention to the water, especially if your pattern
is being ignored or refused. Another way to resolve the spinner versus
dun dilemma is the riseform. Although the rises to the duns are subtle
and sip like, when the trout rise to the spinners, the riseform is barely
perceptible. These very faint sips indicate they are sipping spinners.
Like the dun, the spinner imitation need not be complicated-just make
sure the size and silhouette are correctly matched.
A Pseudocloeon male dun from the West Branch of the Delaware.
It is impractical to fish a Pseudo nymph imitation
effectively on the bottom, due to the size and the quick and evasive manner
of the natural. Pseudo nymphs are, however, very sluggish and clumsy during
actual emergence, and a tiny nymph that floats in or on the surface film
can be quite effective right through the hatch, even though the water
may be covered with floating duns. This is mainly due to the nymph's slow,
drifting ascent, and the difficulty they experience escaping their nymphal
A size 22, 24 or 26 nymph is almost impossible to
see on the water, so at times I tie my nymph imitation on a dropper, which
is attached to a size 16 or 18 (or even a size 24) Comparadun.
The Pseudocloeons are my favorite hatch to fish,
particularly from late September until the end of October, when they hatch
daily in unbelievable numbers on my home rivers on the Upper Delaware.
One of the ultimate accomplishments in fly fishing is to hook, play (pray),
land and release a wild 16" to 18" brown or rainbow on a size
26 fly attached to a 6x or 7x tippet. Go do it-it will be one of the high
points of your season!