Hatches Made Easy:

Little Yellow Quills (Heptagenia Group) - Nymphs and Emergers


These nymphs look a lot like the other crawler nymphs such as Stenonema and
Stenacron species except they are much darker. Some are almost black. In the
late summer and early fall, these nymphs out number the grown mayfly nymphs
in many of the small streams in the park.
These nymphs seem to be much more tolerant of slower moving, warmer water
than most of the other clinger nymphs.
When we have been unable to get the trout to rise to dry flies during the late
summer and early fall months, we usually try a size 16 or 18 dark clinger nymph
imitation. It almost always works even when the water is bordering too warm, very
low and slow flowing.   

The key to fishing the nymph at that time of the year is to make longer cast
using very light, long leaders and tippets. The fish are usually in the heads of
the pools or at the ends of the long runs and riffles. You would think they would
seek the most oxygenated water in the streams but they do not. We find them in
stream samples in the pools and other places you would not expect them to be.
We have tried the riffles with little success.

We have not raised these nymphs in an aquarium and/or been able to
determine exactly how they hatch. The clingers are difficult to keep alive. The
books all say that they hatch into duns a few inches below the surface of the
water and depart the water very quickly. That must be true because you will
rarely spot a dun on the surface. We believe they hatch either early in the
morning or in the evenings.  

We have not tried to fish emerger patterns of this mayfly. I really don't have any
idea as to whether they would be effective or not. As I said above, we have not  
found them hatching during normal daylight hours.

Coming Up Next:
Little Yellow Quills - (Heptagenia group) - Duns and Spinners

Copyright 2008 James Marsh