The Stream Doctor

May 31st, 2004

Email YOUR Questions directly to the Stream Doctor. This is your opportunity to get an experts professional opinion on anything stream related.

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

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

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