Spotted Sedge - Larvae
.............................Fly Fishing Yellowstone National Park


The larvae of the Spotted Sedge (
Hydropsyche species) are eaten by trout to a large
extent. It is the position they find themselves in that makes them easy prey for feeding
trout. They dangle themselves on a silk line attached to a rock. This genus is from the
Hydropsychidae family called net spinners. Net spinners do not build cases to live in.
They build retreats or shelters that they reside in when they are not feeding or moving
from one place to another. Net spinners drift tiny nets in the current to catch their food
or small particles in the water.
If you pick up a rock from the stream to look for these larvae, the net will collapse and
be very difficult to observe  If all other conditions are present, the more algae there are
in a stream, the more likely there are net spinning caddisflies present.  
There are about seventy species in the
Hydropsyche genus. Fortunately for anglers,
there is not much difference in the many species or certainly not enough difference that
the methods of imitating them or the imitation itself (fly) needs to  be very different for
various species. The sizes of the larvae may vary from a hook size 8 to a 16.
Probably every stream in Yellowstone contains Spotted Sedges. Some of them have
huge populations of these insects. They live in the riffles and runs of the streams. They
must have current to survive.  
We have not fished larvae imitations of the
Hydropsyche but a very few times in
Yellowstone. When we did, we were successful in catching fish. We have done so in
many other streams with success, so we feel it is a good method. In Yellowstone, there
are so many options we only resort to a larva or nymph imitation when we have too.
Most of the time we are able to catch fish on the dry fly which we prefer. However, at the
right time and place, fishing imitations of the larvae may be a very good option and for
this reason, we suggest you be prepared with some flies.
We fish the fly without an indicator. We do add some non-toxic weight a few inches
above it. You do not have to keep the fly on the bottom but you do want to keep it in the
lower section of depth of the stream.
The method of presentation we use depends on the stream and type of water. In
general, we fish up and slightly across in pocket water. Hold you rod directly above the
fly and keep all of the fly line you can out of the water to prevent extra drag. You will be
fishing only a few feet (very close) from your position, so this only works in fast, pocket
water. The water should be at least two or three feet deep or you will be likely to spook
the fish. You must make a careful approach without scraping your feet on the bottom.
Follow the fly with the rod tip all the way from the up and across position until it is
directly downstream of your position. You must feel the take in order to know when to
set the hook using this method, so you want to keep a tight line from the fly to the tip of
the rod. In moderate to fast flowing, smooth water we fish down and across allowing the
fly to swing from one side to the other much the same way you would fish a soft hackle
Fishing wet fly imitations of the
Hydropsyche larvae is by no means the most productive
or most enjoyable way to fish Yellowstone but it could be a very good backup strategy  
when you can't put things together otherwise.

Coming Up Next:
Spotted Sedges - Hydropsyche species - Pupae

Copyright 2008 James
Back to Home Page
Back to Home Page