Streams Outside of Yellowstone National Park
.............................Fly Fishing Yellowstone National Park


Fly Fishing Missouri River, Montana - Part 4

The Missouri River doesn't have a huge number of aquatic insects in terms of diversity
but what it lacks in hatches in makes up it quantities. Midges are one of the most
important insects.  This is fairly common of tailwaters. The little two winged flies are
prolific throughout the stream, but especially in the slower areas of the river. Imitations
of midge larvae and pupae is our "go to" flies for the Missouri when nothing else works.

As with most any western trout stream, the most important mayflies are the PMDs or
Pale Morning Duns. The PMDs hatch during the month of June and into August.There
are also hatches of the Blue-winged Olives, mostly
baetis species, that start hatching in
the spring from about March through June and again in the fall from about September
into November.  These two mayflies are about it on the tailwater section below Holter
Dam with one exception - the Tricos. Tricos start hatching about mid July and hatch
through the month of August and into September. They hatch is huge quantities. You
can see clouds of the mayflies covering the water in the early mornings during the
summer. Like anywhere else these tiny mayflies hatch, catching trout on imitations of
them isn't easy. They range in hook size from about 20 to 24.

There are several different species of caddisflies. Hydropsyche species, Spotted
Sedges, are among the most plentiful. There are tons of microcaddis species that can
make it difficult catch trout. They are so plentiful at times it is highly unlikely a trout will
find your tiny imitation among thousands of the real flies. Little Short-horned Sedges
are also quite plentiful. These are a little tan caddisfly.

In addition there are dragonflies, damselfiles, crawfish, leeches, scuds, water boatman
and craneflies. I think that you can see that although there are not a lot of different
mayflies, caddisflies and stoneflies in terms of variety, there is a lot of food available.
That is proven by the fact the trout grow to such a large size. This river has some huge
rainbow trout in it.

One thing that I haven't mentioned is the PH level or the Missouri below Holter Dam. It is
high. That is why there are large quantities of insects there. It is also the reason the
water has a lot of aquatic vegetation in it.

I would like to mention that I have just received all my new adult caddisfly patterns for
our "
Perfect Fly" store. I haven't posted pictures of them yet but they will be up
sometimes during the next three days or so. It is the most complete set of specific adult
(dry fly) caddisfly imitations there are. We have both pupae and adult imitations for
fourteen major species. That represents over 90% of all caddisflies that are present in
trout streams and lakes. I hope you will check it out.  

                                                                                        Copyright 2009 James Marsh
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