.......................  ......Fly Fishing Yellowstone National Park


Fly Fishing Yellowstone - Little Yellow Stonefly Nymphs

The stonefly nymphs are far more important than the adults when it comes to
fishing imitations of them. There are two families that the Little Yellow Stonefly
nymphs come from. 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 color.

As mentioned yesterday, 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.

All of the species of these two families of stoneflies live in fast water. They must
have fast flowing, clean water to survive. Prior to the hatch, the Little Yellow
Stoneflies will move along the bottom from their fast water habitat to the banks
to hatch. Some of them crawl up on stones that protrude out of the water to
hatch but the majority use the banks. Just as soon as they get out of water, they
shed their shucks and fly away. The best chance the trout have to eat them is
during this migration prior to the hatch.  Often, the trout will actually intercept
them along the banks.

These different species of Little Yellow Stoneflies hatch at different times of the
day depending on which species. Most of the Yellow Sallies, or species of the
isoperia genus, hatch in the afternoons. The warmer the weather, the later the
hatch. However, the nymphs will crawl to the banks throughout the day. The
later in the day, the better the fishing usually is, but you can take trout imitating
the migrating nymph anytime during the day.  

If you walk up to the bank and cast or if you walk up to the bank and wade into
the water, you may have spooked the trout you are trying to catch. Where
the trees and bushes allow, you should first cast to the banks from a short
distance away from the banks. Bring the nymph on the bottom all the way back
to the bank. Remember, the trout do not have to see you to spook. If you are
not careful, they can hear you walking on the bank close to the water through
their lateral line. Ease up to the stream as quietly as possible without kicking
rocks, etc. When you do get in the water, wade away from the bank about a
rods length and fish the nymph down and across allowing the nymph to swing
back to the bank. This will work much better than a up stream cast. Continue to
move downstream a foot or two each cast covering all of water along the bank. If
you cast out a few feet, say ten or fifteen feet using a reach cast that ends with
your rod pointing towards mid-stream, you can slowly swing the rod back in the
opposite direction pointing it towards the bank. This will swing the fly from
several feet out in the stream all the way to the bank. In other words you
can cover approximately twenty to thirty feet of water each cast. Of course, this
changes with the particular stream and stream composition. If there is a run
near the bank, you may only need to swing the fly a few feet.

You need to keep the fly twenty feet or more away from you depending
on the water. In shallow water you may need to keep the fly thirty feet or more
from you to keep from spooking the trout. Remember, the trout will be facing you
when you fish downstream. Make sure you keep the fly on the bottom. If it is
swinging up off the bottom mid-depth or near the surface, you are not going to
catch many fish. Weight it down with non-toxic weight and keep it right on the
bottom. When you pick it up slightly off the bottom, the fly will swing towards the
bank a few inches. Let it get back on the bottom before you lift the rod again.

Copyright 2009 James Marsh
Our "Perfect Fly" Little Yellow Stonefly (Yellow Sally) Nymph