|....................... .................... ...Fly Fishing Yellowstone National Park
New KISS Bug Series - Part 28
Spotted Sedges (Caddisflies)
The Spotted Sedge larvae, or larvae of the hydropsyche species of caddisflies, are eaten by trout
throughout their one year life cycle. They are not difficult for the trout to find or catch. They extend out in
the open areas over the bottom from a silk line attached to a rock near their shelters. This genus from the
Hydropsychidae family and are 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.
These shelters are similar to sheds and not totally enclosed. The caddisflies catch their food by making tiny
nets to catch their food from the current.
These nets are like little tiny parachutes. If you pick up a rock from the stream to look for these larvae, their
nets will collapse and be very difficult to observe They would be difficult to see with the naked eye when
collapsed. Net spinning caddisflies rely on algae. 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's not much
difference in the many species or certainly not enough difference that the methods of imitating them or the
imitations themselves (flies) need to be different for the various species. I would venture to say that every
stream in Yellowstone National Parki contains Spotted Sedges. Some of them have huge populations of
these insects. They usually live in the riffles and runs of the streams but provided other conditions are met,
they can live anywhere there is current. They must have current to survive.
The best way to fish our Perfect Fly Imitation of the Spotted Sedge is free without an indicator but strike
indicators will produce some results. If your not use to fishing subsurface flies without an indicator, then you
should probably use one. There is a slight learning curve to fishing nymphs or any subsurface fly without
an indicator or as a dropper fly from another fly on the surface. We fish the fly without an indicator.
You should 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 part of the stream near the bottom. The exact method of
presentation you should use depends on the stream and type of water. In general, you should fish up and
slightly across in pocket water streams. Hold you rod high and keep all of the fly line you can off of the
water to prevent extra drag. You will be fishing only a few feet (very close) to your position, so this only
works in faster moving, pocket water of a decent depth where your not apt to spook the trout. 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 it's best to fish down and across. In this case, allow the fly to
swing from one side to the other much the same way you would fish a soft hackle fly on the swing. You want
to use a longer cast and allow the fly to accent to the surface in the same general area the trout are eating
the emerging Spotted Sedge pupae. Just by stopping the tip of the rod at about a 45 degree angle from
the horizon, the current will bring the fly back to the surface. That's where the trout normally eat the pupa
imitation regarding of the type of water.
Availability to trout:
Type of water:
Duration of hatch period:
Moderate to slow - smooth and broken surface