Q.
I had the good fortune to visit Colorado last
summer, and a chance to fish the Frying Pan River.
I experienced big caddis, green drake, and other
mayfly hatches at high noon in the blazing sun
with air temperatures over ninety degrees! Almost
all of the hatches this size I’ve experienced in
N. California were caddis just about the time it’s
too hard to see to tie a knot. I also fish
tailwaters here where most trout are reluctant to
come to the surface, even during a relatively good
hatch. What causes these differences? Thanks.
A.
If you’ve read any of my previous responses concerning
insect hatching and temperature, you’ll know that
aquatic insects require a certain number of
degree-days to hatch; when they have experienced
the required number, they hatch, regardless of
whether it is high noon, evening, hot, or cool.
Some insects respond to various light conditions
and emerge more readily when the preferred light
conditions are present; that might explain why
the caddis in N. California emerge under low
light conditions. Again, many of these traits
are species-specific, so it is hard to generalize
on some of these things. The reluctant trout may
find plenty to feed on in the deeper waters, thus
they don’t have any reason to chase hatches - that’s
a guess.
If you have a question, please feel free to contact me.
~ C. E. (Bert) Cushing, aka Streamdoctor
105 W. Cherokee Dr.
Estes Park, CO 80517
Phone: 970-577-1584
Email: streamdoctor@aol.com
The ‘Stream Doctor’ is a retired professional stream ecologist and
author, now living in the West and spending way too much time
fly-fishing. You are invited to submit questions relating to
anything stream related directly to him for use in this Q & A Feature
at streamdoctor@aol.com.
Originally published May 31st, 2004 on Fly Anglers Online by Robert Younghanz.