Blue-winged Olives are very
common in the park and usually
exist in large quantities. There are
many different species of them.
common in the park and usually
exist in large quantities. There are
many different species of them.
Golden Stoneflies are very
common in most of the park's
streams. They can really turn the
trout on for some fast action.
common in most of the park's
streams. They can really turn the
trout on for some fast action.
Aquatic Insect Hatches:
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| .............................Fly Fishing Yellowstone National Park |
Caddisflies of many species live in
the park. To be successful on
many of the streams, you must
know how to fish the caddisfly
hatches.
the park. To be successful on
many of the streams, you must
know how to fish the caddisfly
hatches.
Small Western Green Drake
You will find that the Yellowstone National Park
has a huge diversity of aquatic insects. This
large variety of insects has caused many
anglers to shy away from trying to determine
what insects the trout may be feeding on at any
given time and place.
Mayflies:
Caddisflies:
Stoneflies:
Midges:
Other Aquatic Insects:
Importance:
Many anglers are of the opinion that hatches are
not important in the park. This same line of
thinking is largely responsible for those same
anglers labeling fishing conditions as excellent,
good, average and bad. When they fail to catch
trout using their standby methods and fly
patterns, they sometimes falsely assume that
fishing is bad.
In general, determining what food the trout are
taking is just as important in the park as it is in
any stream anywhere in the nation.
Hatch Intensity:
Most anglers haven't seen large hatches such
as they can see at times in the park, especially
on the Madison, Firehole and Yellowstone
Rivers. They are, for the most part, not aware
that hatches on the other small, headwater
mountain streams can also be prolific. In fact,
hatches in Yellowstone National Park are often
as prolific and as common as they are
anywhere, if you compare them to other
headwater, mountain freestone streams.
Pocket Water:
One reason for the lack of consideration for
hatches in the park is the fact that attractor
patterns work very fairly well in some of the
streams. This is not a product of the park itself
rather the type of water found in the park. Much
of the water is pocket water. Without going into
detail let us just say that in many situations the
trout simply do not have time to closely examine
the fly.
Slow Moving Water:
When they do, they can be just as picky as trout
found anywhere. Many anglers fail to catch trout
when they are in the smoother flowing, clear
water or slow to moderate smooth flowing
shallow, low water conditions. They usually just
ignore the pools altogether and for good
reasons. The attractor flies perform very poorly
where they can closely be observed by the trout.
Some of the streams such as the Firehole and
Madison have slow to moderate currents that
are very tricky. The water swirls from the grass
and the currents run at different speeds.
Conflicting currents are the normal thing. This
makes for tough conditions of presentation and
for the fly pattern. Many of the streams, such as
the Gibbon and Belchler Rivers have meadow
sections that have slow to moderate water that
is slick and tough to fish. In these locations the
fly can be very important because the trout get a
very good opportunity to examine the fly closely.
Oxygenated Water:
Normally some trout, especially the rainbows,
can be found to some extent in the fast moving,
pocket water. One reason for this is that during
the hot summer months of the year on some
lower elevation streams the water temperatures
in the park are on the warm side of that
preferred by trout. Since warm water holds less
dissolved oxygen the trout have to seek the
oxygenated water to survive. During this time
they tend to stay in the faster water such as
plunges, runs and pockets.
Standby flies such as the Adams, a pattern that
to some extent imitates any mayfly and maybe
even some caddisflies, often work well.
Some of the very high headwater streams in the
park have a low PH. In this type of water, the
insects have little to feed on. Insects that feed
on algae exist in these types of streams but not
in large quantities. Acidic water doesn't contain
much plankton or algae. Several species of
aquatic insects exist in large enough quantities
to cause the trout to feed selectively in the park.
Opportunistic Feeding:
In most of the small pocket water type streams,
most often the trout are feeding
opportunistically. In other words they eat a
variety of food and sometimes just about
anything they can find.
Selective Feeding:
Trout can and do feed selectively in the park.
There are usually several different species of
insect available for the trout. When trout select
only one species of insect, or other food for that
matter, and feed on it exclusively, there is alway
an abundant amount of the food available. They
do this because they can feed more efficiently.
They feed heavily on the most prevalent food
and ignore the others. They no longer have to
resort to looking for food. They can stay in one
place and eat all they want. They can maximize
their food intake while minimizing their energy
expenditure. This is not a choice the fish
makes. It is a trained response.
Impressionistic Imitations:
Generic imitations, sometimes called
impressionistic imitations, work often when
specific imitations do not. If an angler is using a
specific imitation of something the trout are not
feeding on, then they may be better off with a
generic imitation that represents a variety of
insects.
Specific Imitations:
On the other hand, often when the trout are
feeding exclusively on insects of a certain
species in the park, anglers fail to catch trout
consistently because they do not use a specific
imitation. This occurs far more often when the
trout are feeding on nymphs, larvae or pupae
stages than it does when they are feeding on
insects on the surface of the water. Underwater
selectivity is the least understood topic in fly
fishing for trout. The reason is very simple. You
can't see what the trout are eating under water
very well and usually, not at all. During these
times most anglers are satisfied to believe that
fishing is poor. They fall back on the stereotyped
labels for fishing conditions.
Different Viewpoints:
Marine or fish biologist (behavioral scientist)
tend to believe that fish feed only
opportunistically. If trout were not somewhat
selective, they would starve. They can tell the
difference most of the time in tiny leaves, twigs
and other stuff that look somewhat, at least from
an impressionistic standpoint, like little insects.
They eat a few things by mistake but not much
or they would starve. They can dang well rise
beneath your fly on their way to eat it and
suddenly turn away from it, rejecting it. When
that happens they are being selective about
what they eat. Selectivity is not something that is
either in effect or not in effect. It is a matter of the
degree it exist at the particular time and at the
particular place. Don't misunderstand me
please. It is just a matter of definition - selectivity
and the angler sees it or selectivity as the
scientist see it.
Examples of Selective Feeding:
These are some of the aquatic insects that can
cause selective feeding in Yellowstone's
streams. There are others but these are some
of the most common.
PMDs or Pale Morning Duns:
The pale morning duns are one of the mayflies
that can cause trout to feed selectively. This can
be a frustrating hatch. Trout can even become
selective on one stage of the hatch and pay little
attention to the other stages. This happens
often with the emerging stage of the mayfly.
Trout will take the easy way and eat them when
they are emerging just below the surface.
Blue-winged Olives:
Blue-winged olive hatches that usually occur
during the first part of the season and again
during the latter part of the season can cause
trout to become selective on them in some
streams. This can be challenging fishing,
especially on the smooth flowing streams.
Salmonflies:
The huge salmonfly nymphs can certainly
cause the trout to feed selectively in some
streams but probably not as much as the
average angler expects they do.
Golden Stoneflies:
The Golden Stoneflies can really confuse the
match the hatch situation. Often when both the
adult salmonflies are still around the golden
stoneflies are hatching. The trout can ignore the
egg laying salmonflies and eat the emerging
golden stoneflies.
Western Green Drakes:
Certainly at the right time on the right stream the
trout can become selective on the Western
Green Drake. This is a large mayfly and where
they hatch in large quantities, the trout will
usually concentrate on them.
Flavs or Small Western Green Drakes:
The Small Western Green Drake is also
plentiful in some streams in the park, especially
the Firehole River. The trout can become
selective on them.
Gray Drakes:
The Gray Drake is common to many streams in
the park. Where the are, Slough Creek for
example, they can cause selective feeding.
Spotted Caddis:
Certainly the very common and very plentiful
spotted caddisfly can cause the trout to feed
selectively. This can go on for quite a while in
the summer on some streams.
Little Sister Caddis:
Not as plentiful but existing still in large
quantities is the Little Sister Caddisfly. We have
seen the trout become selective on these. The
lower section of the Gibbon River has a large
hatch in July.
Conclusion:
To be successful fishing the various streams of
Yellowstone National Park, an angler must
understand the different types of water and the
hatches. Attractor patterns will work in some
cases and not in others. You must know when
and where these difference occur.
You must also understand the behavior of the
aquatic insects in order to catch fish
consistently. Just having he right fly is not
enough. You must know where and when to
present it and how to present it to be successful.
Copyright 2007 James Marsh
has a huge diversity of aquatic insects. This
large variety of insects has caused many
anglers to shy away from trying to determine
what insects the trout may be feeding on at any
given time and place.
Mayflies:
Caddisflies:
Stoneflies:
Midges:
Other Aquatic Insects:
Importance:
Many anglers are of the opinion that hatches are
not important in the park. This same line of
thinking is largely responsible for those same
anglers labeling fishing conditions as excellent,
good, average and bad. When they fail to catch
trout using their standby methods and fly
patterns, they sometimes falsely assume that
fishing is bad.
In general, determining what food the trout are
taking is just as important in the park as it is in
any stream anywhere in the nation.
Hatch Intensity:
Most anglers haven't seen large hatches such
as they can see at times in the park, especially
on the Madison, Firehole and Yellowstone
Rivers. They are, for the most part, not aware
that hatches on the other small, headwater
mountain streams can also be prolific. In fact,
hatches in Yellowstone National Park are often
as prolific and as common as they are
anywhere, if you compare them to other
headwater, mountain freestone streams.
Pocket Water:
One reason for the lack of consideration for
hatches in the park is the fact that attractor
patterns work very fairly well in some of the
streams. This is not a product of the park itself
rather the type of water found in the park. Much
of the water is pocket water. Without going into
detail let us just say that in many situations the
trout simply do not have time to closely examine
the fly.
Slow Moving Water:
When they do, they can be just as picky as trout
found anywhere. Many anglers fail to catch trout
when they are in the smoother flowing, clear
water or slow to moderate smooth flowing
shallow, low water conditions. They usually just
ignore the pools altogether and for good
reasons. The attractor flies perform very poorly
where they can closely be observed by the trout.
Some of the streams such as the Firehole and
Madison have slow to moderate currents that
are very tricky. The water swirls from the grass
and the currents run at different speeds.
Conflicting currents are the normal thing. This
makes for tough conditions of presentation and
for the fly pattern. Many of the streams, such as
the Gibbon and Belchler Rivers have meadow
sections that have slow to moderate water that
is slick and tough to fish. In these locations the
fly can be very important because the trout get a
very good opportunity to examine the fly closely.
Oxygenated Water:
Normally some trout, especially the rainbows,
can be found to some extent in the fast moving,
pocket water. One reason for this is that during
the hot summer months of the year on some
lower elevation streams the water temperatures
in the park are on the warm side of that
preferred by trout. Since warm water holds less
dissolved oxygen the trout have to seek the
oxygenated water to survive. During this time
they tend to stay in the faster water such as
plunges, runs and pockets.
Standby flies such as the Adams, a pattern that
to some extent imitates any mayfly and maybe
even some caddisflies, often work well.
Some of the very high headwater streams in the
park have a low PH. In this type of water, the
insects have little to feed on. Insects that feed
on algae exist in these types of streams but not
in large quantities. Acidic water doesn't contain
much plankton or algae. Several species of
aquatic insects exist in large enough quantities
to cause the trout to feed selectively in the park.
Opportunistic Feeding:
In most of the small pocket water type streams,
most often the trout are feeding
opportunistically. In other words they eat a
variety of food and sometimes just about
anything they can find.
Selective Feeding:
Trout can and do feed selectively in the park.
There are usually several different species of
insect available for the trout. When trout select
only one species of insect, or other food for that
matter, and feed on it exclusively, there is alway
an abundant amount of the food available. They
do this because they can feed more efficiently.
They feed heavily on the most prevalent food
and ignore the others. They no longer have to
resort to looking for food. They can stay in one
place and eat all they want. They can maximize
their food intake while minimizing their energy
expenditure. This is not a choice the fish
makes. It is a trained response.
Impressionistic Imitations:
Generic imitations, sometimes called
impressionistic imitations, work often when
specific imitations do not. If an angler is using a
specific imitation of something the trout are not
feeding on, then they may be better off with a
generic imitation that represents a variety of
insects.
Specific Imitations:
On the other hand, often when the trout are
feeding exclusively on insects of a certain
species in the park, anglers fail to catch trout
consistently because they do not use a specific
imitation. This occurs far more often when the
trout are feeding on nymphs, larvae or pupae
stages than it does when they are feeding on
insects on the surface of the water. Underwater
selectivity is the least understood topic in fly
fishing for trout. The reason is very simple. You
can't see what the trout are eating under water
very well and usually, not at all. During these
times most anglers are satisfied to believe that
fishing is poor. They fall back on the stereotyped
labels for fishing conditions.
Different Viewpoints:
Marine or fish biologist (behavioral scientist)
tend to believe that fish feed only
opportunistically. If trout were not somewhat
selective, they would starve. They can tell the
difference most of the time in tiny leaves, twigs
and other stuff that look somewhat, at least from
an impressionistic standpoint, like little insects.
They eat a few things by mistake but not much
or they would starve. They can dang well rise
beneath your fly on their way to eat it and
suddenly turn away from it, rejecting it. When
that happens they are being selective about
what they eat. Selectivity is not something that is
either in effect or not in effect. It is a matter of the
degree it exist at the particular time and at the
particular place. Don't misunderstand me
please. It is just a matter of definition - selectivity
and the angler sees it or selectivity as the
scientist see it.
Examples of Selective Feeding:
These are some of the aquatic insects that can
cause selective feeding in Yellowstone's
streams. There are others but these are some
of the most common.
PMDs or Pale Morning Duns:
The pale morning duns are one of the mayflies
that can cause trout to feed selectively. This can
be a frustrating hatch. Trout can even become
selective on one stage of the hatch and pay little
attention to the other stages. This happens
often with the emerging stage of the mayfly.
Trout will take the easy way and eat them when
they are emerging just below the surface.
Blue-winged Olives:
Blue-winged olive hatches that usually occur
during the first part of the season and again
during the latter part of the season can cause
trout to become selective on them in some
streams. This can be challenging fishing,
especially on the smooth flowing streams.
Salmonflies:
The huge salmonfly nymphs can certainly
cause the trout to feed selectively in some
streams but probably not as much as the
average angler expects they do.
Golden Stoneflies:
The Golden Stoneflies can really confuse the
match the hatch situation. Often when both the
adult salmonflies are still around the golden
stoneflies are hatching. The trout can ignore the
egg laying salmonflies and eat the emerging
golden stoneflies.
Western Green Drakes:
Certainly at the right time on the right stream the
trout can become selective on the Western
Green Drake. This is a large mayfly and where
they hatch in large quantities, the trout will
usually concentrate on them.
Flavs or Small Western Green Drakes:
The Small Western Green Drake is also
plentiful in some streams in the park, especially
the Firehole River. The trout can become
selective on them.
Gray Drakes:
The Gray Drake is common to many streams in
the park. Where the are, Slough Creek for
example, they can cause selective feeding.
Spotted Caddis:
Certainly the very common and very plentiful
spotted caddisfly can cause the trout to feed
selectively. This can go on for quite a while in
the summer on some streams.
Little Sister Caddis:
Not as plentiful but existing still in large
quantities is the Little Sister Caddisfly. We have
seen the trout become selective on these. The
lower section of the Gibbon River has a large
hatch in July.
Conclusion:
To be successful fishing the various streams of
Yellowstone National Park, an angler must
understand the different types of water and the
hatches. Attractor patterns will work in some
cases and not in others. You must know when
and where these difference occur.
You must also understand the behavior of the
aquatic insects in order to catch fish
consistently. Just having he right fly is not
enough. You must know where and when to
present it and how to present it to be successful.
Copyright 2007 James Marsh
Thumbnails-Click on images.
Rainbow Trout
Flyfishingdvd's Imitating Aquatic
Insects: Stoneflies will teach
you what you need to know about
stoneflies and how to imitate
their behavior.
Insects: Stoneflies will teach
you what you need to know about
stoneflies and how to imitate
their behavior.
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