Little Black Caddis - Pupae
.............................Fly Fishing Yellowstone National Park
04/13/08

Little Black Caddis pupae swim to surface when emerging.  The hatch resembles that of
a typical mayfly hatch in that respect. That is one thing that makes this hatch important
to anglers. These caddisflies don't usually hatch in shallow water or near the edge of a
stream like many aquatic do. They usually hatch mid-stream and by that I mean
anywhere out in the stream.
The Little Black Caddis hatch usually starts in the early afternoon and can last until late
afternoon. Often the hatch is still underway when the female adults begin to deposit
their eggs on the surface. This usually occurs later in the afternoon and can add
activity to the point it becomes a feeding frenzy.  
I have read that the pupae swim to the surface using their middle legs aided by air
bubbles. I have not been able to actually observe this even though I have raised them
in an aquarium. I will have to accept others word that this is how the pupae manage to
get to the surface. They hatch in the surface skim by shedding their thin pupa skin and
drying their wings. They then proceed to fly away to the stream side bushes, trees or
grass.
It is during the time that the pupae are accenting to the surface and changing
into an adult fly that the trout feed on them the most.
I have seen this many times
in many different streams in the West. The trout will just flash or swirl beneath the
surface when they are taking the pupae. Sometimes you can see the surface
disturbance and sometimes you cannot. It depends on the particular type of water. I
believe that far more pupae are eaten by trout that newly hatched adults. This is
certainly a stage of the hatch you want to be able to imitate.

Pupae Presentation:
The pupae usually hatch in water that is relatively smooth even in streams that consist
mostly of fast moving pocket water. They seek the slower, smoother areas of the
stream, such as the pockets behind rocks, to emerge. If you are fishing pocket water,
then I would suggest you use an across stream presentation of the pupae imitation.
Under these conditions, you can get much closer to the feeding trout fishing upstream.  
In smooth flowing streams you may be better off using a down and across presentation.
It can be difficult to get very close to the feeding trout in smooth flowing water.  
With either type of presentation, across stream or downstream, you want to imitate the
pupa swimming to the surface to hatch. You do that by simply stopping the rod near the
end of the drift and allowing the fly to rise back up to the surface. The current will bring
the fly back to the surface for you.  
Both the Madison and Firehole Rivers have sections of fast moving pocket water and
large, smooth flowing sections of water depending on the particular part of the stream
you are fishing. The Little Black Caddis hatch is usually still in progress when the
season opens in both these streams as well as the lower part of the Gibbon River.
Some of the other streams in the park also have hatches that occur after the season
opens, but keep in mind, the hatch may be affected by the Spring runoff in many cases.

Coming Up Next:
LIttle Black Caddis - Adults

Copyright 2008 James Marsh