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


Henry's Fork of the Snake River Hatches - Part 3

The hatches at the Harriman State Park section of the river, called the Ranch by many
anglers, are similar to those I gave yesterday for the section below Aston Dam. The
times are different. The Harriman State Park section is a spring creek or spring river
with smooth flowing water and is quite different than the tailwater below Aston Dam.
The water temperatures are different most of the time, for one reason, because it is at
a higher elevation and another because it is not directly below a dam. It is below Island
Park dam, but not directly. There is the box canyon, an entirely different type of river
section between them. The fast moving pocket water has slightly different hatches and
hatch times. I will cover it tomorrow.

There are probably as many different species of aquatic insects in the Harriman State
Park section of the Henry's Fork of the Snake River as there are anywhere in the
Western United States. However, there is one insect that dominates the minds of most
anglers - the Western Green Drake. It is very good for the Island Park economy for
sure. In recent years there have been many stories and jokes told about the Green
Drakes at the Henry's Fork. One of my favorites is that when the hatch starts, the
locals will say "the green drakes are hatching and the fish are feeding great - on the
caddisflies". There is some truth in that statement. There are a lot more caddisflies in
the water than green drakes, for one thing. Another thing is that the green drake hatch
is subject to a lot of things such as fewer insects than times in the past and a short
hatch period of time. About a week or ten days is about as long as the big drakes are
going to hatch in any large numbers. Being there at the right time isn't easy to do if you
only have a few days to fish. We have always been in the Yellowstone area for at least
a month and that does allow you to be able to get there during the hatch if you desire.
We haven't always taken the green drakes up on that offer though. The Henry's Fork
has its largest crowds during that time for one reason. It usually occurs near the end of
the month of June. The season in that section doesn't open until June 15 due to
nesting water foul.

It is not necessary to catch the Green Drake hatch to catch trout. Its fine if you do but
not necessary. The fish feed more than one week a year. I am not going through each
insect and the hatch times but I will refer you to a hatch chart we have on our website. This link will show the hatch times which are centered
around the Henry's Fork area. Keep in mind they show a wide range of dates for the
entire river, so they are not specifically for the Ranch section. I will note some
difference below.

Pale morning duns and
baetis Blue-winged Olives will most likely greet you on opening
day. We show the big Green Drakes starting on the 15th but most likely nearer the end
of the month for this section. The Lesser Green Drakes, or Flavs as most anglers call
them, hatch during July. You will also find some large Brown Drakes that hatch in some
sections near the same time of the month. They may not start until around the first of
July. About the middle of July you may find the Callibeatis (Speckled Wing Quills)
mayflies hatching. Those are basically still water mayflies but they hatch in some
sections of the Ranch area. This hatch can last through the month of August. We have
done just as well in July and August on terrestrial patterns - ants, beetles and hoppers
as we have mayfly imitations. You can walk the banks and fish these flies and not have
to be as precise with your presentations although it still takes plenty of skill to be
consistently successful. The entire season you will find caddisflies hatching. They are
mostly the Spotted Sedges, Little Sisters and a dozen other species. Check our hatch
chart for more specific information.

Copyright 2008 James Marsh     
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