Hatches Made Easy:

Little Yellow Stoneflies (Perlodidae and Peltoperlidae Family) Nymphs

04/03/08

Nymphs:
Stonefly nymphs are far more important than the adults from a fly-fishing
standpoint. They represent a large part of the diet of the trout in the Smokies.
When we have taken samples of the aquatic insects from the streams, we have
found stoneflies often represent the majority of nymphs in terms of mass.
The Smokies have species of all (9) nine families of stoneflies. Of all the
families present, the Perlodidae and Peltoperlidae families represent more than
any of the others in terms of sheer numbers.
The species of the Periodidae family, the most important one, differ in size but
their basic color and shape is very  similar. Species of the Peltoperlidae family
are shorter and more rounded than the Periodidae species but all the species
within the family are very similar in shape and basic color.
Like all stoneflies (with rare exceptions), the Little Yellow Stoneflies
crawl out of
the water to hatch
. The nymphs are much more susceptible to being eaten by
trout when they migrate from their normal locations down in between and under
rocks on the streambed to the banks to hatch.
When there is no hatch taking places, the stoneflies are basically safe from the
trout. It is not unusual for one to become dislodged and to subject to being
eaten. They don't show up that regular in drift samples; however, and I doubt it
is a frequent occasion. Behavioral drifts, which usually occur under low light
conditions or during the night, don't have substantial numbers of stonefly
nymphs.
There are so many different species of stoneflies in the streams of the Smokies,
including the Little Yellow species, there is a hatch occurring more often than not
from late winter until early fall. The bottom line to this is that
your odds of
success are good if your are fishing stonefly nymph imitations most any
day
during that time.
Of all the Little Yellow species,
the Yellow Sallies provide the best
opportunity for anglers
. They often hatch during the daytime, whereas many
other stonefly species hatch during the evening hours. Some of the Little Yellow
Stonefly species that hatch during very warm weather also hatch during the
evenings.

Coming Up Next:
Imitating the Little Yellow Stonefly Nymphs

Copyright 2008 James Marsh