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


Fly Fishing the Bitterroot River, Montana - Part  3

The river varies it types of water considerably during its eight mile course and
consequently, the hatches vary. So, when I discuss hatches on the Bitterroot, you need
to keep in mind that some of them exist only in certain sections of the river. For
example, the Bitterroot has some huge hatches of Trico mayflies. You want find them in
the fast water runs and riffles that exist in several places in the two headwater forks or
several sections of the main river.

The runoff period on the Bitterroot River usually occurs from about the first of May until
the end of May or early June. Of course, this always varies greatly depending on the
snow pack. There can be some good fishing prior to the runoff starting as early as
March. March and April can bring some hatches of Blue-winged Olives as well as the
Skwala Stonefly hatch. Little Brown stoneflies (which are black winter stoneflies) also
hatch during this time. These hatches can last until the end of April. From about mid
March until mid April, March Browns will hatch in the faster water sections. The Mother's
day Caddis hatch from about mid April until mid May. Fishing during the May and early
June runoff period is just about impossible. This river drains a very large area of high
mountain snow packs. From mid June on, the water is usually in great condition. The
exception to this is the tailwater of the West Fork. I am told It stays clear even during the

The salmonflies hatch from near the first of June into the first part of July depending on
which section of the river you are referring to. Golden stoneflies start about the same
time, usually just after the salmonflies. It can last two or three weeks longer than the
salmonflies. Yellow sally stoneflies also hatch during this time. They start before the
runoff is over but some species of them hatch throughout most of July. From the end of
June until the first of July, the Spotted Sedges can become a big factor on certain parts
of the river.

Mahogany Dun mayflies hatch from about the first of June and into the month of
August, depending on the section of the river. There is also a later hatch of these small
mayflies, usually in September to mid October. The large Western Green Drakes start
from about the middle of June and last until mid July, again, depending on the location
on the river. They only last about a week in any one area of the river. The most
consistent mayfly to hatch is typical of most western hatches - the PMD or Pale Morning
Duns. Two species of these little mayflies hatch from about mid June until the middle of

Grasshoppers are very important during the summer months. The river flows through a
agriculture area with lots of grass and hay. Don't overlook the beetles and ants.

From about the middle of July through the month of September, you can find the tiny
Tricos hatching in the slower, smoother sections of the river. For the most part, this is
on the lower end of the Bitterroot. September brings more hatches of the Blue Winged
Olives. Another hatch of a different species of March Browns (
Rhithrogena) also occurs
in September. The Blue-winged Olive hatches can last almost through the month of
October. October also brings on some good hatches of the large October Caddisflies.
This can last into the first of November.

As you can see, there are a lot of hatches that occur on the Bitterroot River.

                                                                                                         Copyright 2008 James Marsh
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