Information and tips for tyers, as well as information on hatches.
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Post by S.T.Fanatic » Wed Jun 19, 2019 7:03 am

I have noticed the past several years at our property a few different varieties of mayflies. The stream is small and cool enough to support a healthy brook trout population but warm enough for chubs, suckers, and to produce some big brown trout from time to time. I haven't made it a point to get to know my "bugs" in depth. I know what a mayfly is just dont know the different sub species. We have at least two different caddis species, and I see plenty of small stone flies and midge in the winter to early spring time.

I'm usually not down there during the morning and midday hours outside from "the rut" for deer hunting and i'm not paying attention to what is going on for hatches that time of year (if any). What I have noticed the past couple of years is about 3 different mayflies that seem to become active close to dark in the evenings.

As far as hatches go are there certain types of mayflies that are more active at different times of day that would help me to better identify what species are active? I have only been able to capture a couple flies over the years and when googling for ID it seems that there are variations in color/patterns or just so many different flies that it is difficult to ID them accurately.

Last night I saw at least two different mayflies. It was close to dark so it was hard to get a real good description but one was large and what looked to be brown (at least it was lighter) the other was fairly small and looked quite dark.
“What more delightful avocation than to take a piece of land and by cautious experimentation to prove how it works. What more substantial service to conservation than to practice it on one's own land?” Aldo Leopold

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Re: mayflies

Post by brntrout » Wed Jun 19, 2019 10:20 am


"Generally" the majority of mayflies emerge during day light hours. The mayflies you saw close to dark are likely mayfly spinners. The large brown mayfly could be Brown Drakes( just an assumption) or possibly even March Brown mayflies. During this time of year there really isn't any other mayflies that large on most trout streams so its probably one of the two species.

IMO the best book for identifying trout stream mayflies in our region of the country is called "Hatches" by Al Caucci & Bob Nastasi. They also did a later updated version called "Hatches II" the color plates and keys they show for identifying different mayfly species should make it relatively easy to identify 95 % of the mayflies you see in SE MN. The two books are really easy to understand and if you use them a fair amount you will catch on rather quickly how to identify the different mayfly species. Another "great book" is called Dave Whitlock's - Guide to Aquatic Trout Foods. This book covers every type of food trout eat and is easily understood right out of the gate! Both books can probably be found on Amazon or similar places.

If your trying to identify mayflies( or other bugs)its best to capture a few and put them in small container and examine them at home under good light.

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Re: mayflies

Post by jrs » Wed Jun 19, 2019 8:56 pm

A couple more resources ...

DNR hatch chart: ... 080405.pdf This isn't perfect, but will give you a short list of suspects to start with. This has lots of detail and pictures, but it works best if you have some inkling of the bug name to start with.

I carry a camera and small ruler on stream. I take a picture of bugs with the ruler included in the photo if I run across some thing that I want to study further.

Here's a link to a picture of a SE MN Brown Drake for example ...

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