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Sunday, February 2, 2014

Patterns - The Skwala Stone and the Lower Yuba River

Skwala Pattern Notes

When matching the Lower Yuba River Skwalas remember that the bugs here locally are different in color than their cousins in Washington and Montana. A lot of the patterns for sale in the flyshops or on-line are different in color. Our local Skwalas have an abdomen that is a dirty yellow with a slight olive tinge. Also, the wings are dark gray. This is where it really pays to collect some specimens from the river and take them home to match the color.

Look for the shucks around the bushes and rocks to give you an idea on recent hatch activity. Catch an adult, turn over some rocks and catch a nymph. Match the color and size.

Skwala Nymph’s Characteristics

Color: Dirty Olive with a slight olive tinge, lighter on bottom sometimes yellowish

Size: 17-21mm

Defining physical characteristics: Two long antennae, two tails, 2 separate pair of wing pads, 3 sets of legs, external hair-like gills between legs, t-shaped claws at end of each leg.

Skwala Dry Fly Notes

Adults Color: Olive to dark brown with mottled orange around the legs

Size: 17-21mm

Defining Physical Characteristics: Adult female Skwala's will have a pronounced egg sack dark purple to black in color and about 2-3mm in diameter under their abdomens. The female Skwala sits low in the surface film while she is depositing her eggs and will be readily available to trout.

Pattern Characteristics

Most Dry Skwala patterns are imitated by a Stimulator type pattern. They are tied in a size #10, with a 3x long hook. It is important that your pattern sits low in the surface film. If you watch the female adult on the water, you will see that it looks like a stick with moving legs. The low riding Skwala Dries should have the female’s prominent black egg sack. Trim the hackle on the bottom of the fly so it will to settle into the surface film.

Fishing Techniques

When are the times to imitate Skwalas to be sucessful:

  • As active nymphs they are often found in the water/food column for the trout, being knocked loose and free drifting. This is especially true during pre-hatch periods when their movement activity increases dramatically.

  • They are also available to the trout as the female adult returns to the water to lay eggs.

  • On a windy day as the adult is blown on to the water, and;

  • As a spent adult that falls on the water to die.
How to Present Imitations

  • Use as either an impressionistic searching fly or as a realistic imitation when matching the hatch

  • Drift the fly through different water types; faster riffles and shallower water near the banks of a river with moderate to slow currents are the most productive water types for this fly

  • Skwala stoneflies are available to trout during the early season (January – April) on the Lower Yuba River

  • Hatches occur consistently and with long duration throughout the daylight hours

  • Strikes on skwala stoneflies are often far from subtle because trout must often be prepared to rip these strong clingers from their rocky homes

  • When approaching a shallow water environment with a stonefly imitation, be extremely careful not to spook happily feeding trout

How to Rigg for Nymphing

Set up for nymph fishing with a two or three rigg under indicator.

  • Rigg with a tapered 9 ft 2x or 3x leader to a tippet knot.

  • Add 12 “ of 3x fluorocarbon to your favorite Skwala stone nymph imitation (Mercers Skwal Stone, hint)

  • Put split shot at the tippet knot above the stonefly nymph. The knot will stop the split shot from sliding down to the fly.

  • Tie 4x Flurocarbon tippet to the hook bend of the Stonefly nymph and extend 12” to 16” to a caddis pupa dropper.

  • Tie 5x Flurocarbon tippet to the hook bend of the caddis pupa nymph and extend 12” to 16” to a mayfly BWO or PMD nymph.
How to Rigg For Dries

  • Rigg for a standard dry fly presentation

  • Use a tapered 10 ft. 4x tapered leader

  • Extend tippet using 4x flurocarbon 24" +/-

  • Attach your favorite Skwala Dry pattern

Skwala Nymph Patterns

Hogan's Yuba Rubber Leg Stone

This is Hogan Brown's stone fly pattern. Like many of his patterns it's a keeper.


Hogan's Bottom Roller

Hogan's Bottoms Roller is another good looking stone fly nymph.


Willies Yuba Skwala Nymph

Hook: TMC or Targus 200R #4 - 14
Thread: Black
Abdomen: Copper Flashabou or Braid
Collar: Peacock Herl
Underwing: 4 Peacock Herl Tips
Overwing: Copper FlashabouHackle: Guinea
Optional: Copper bead.

Anderson’s Rubber Leg Stone

Hook- TMC5263 with weight added
Thread- Dark Brown 3/0
Tail- White round rubber leg sections
Abdomen- Cream on bottom to match hares ear thorax and medium brown woven synthetic fuzzy yarn on top
Legs- White round rubber leg material
Thorax- Medium brown hares ear and muskrat dubbing left shaggy.\

Pattern Designer: George Anderson.

Note: Adjust coloration to naturals on the Lower Yuba

The People's Stonefly
Created by Jeff Morgan
HOOK: Dai Riki 700BB, sizes 6-10
THREAD: To match body color
UNDERBODY: Lead wire or tape, flattened and cut to shape
TAIL: Golden-brown goose biots, tied in a "V"
BODY: Tan Kaufmann's blend
BACK: Brown Body Stretch
RIB: Fine brass or copper wire
THORAX: To match body
LEGS: Two pairs of black rubber legs
WINGCASES: Three sections of brown body stretch, cut into "Vs"
ANTENNAE: Golden-brown good biots, tied in a "V"
HEAD: Brass bead


Mercer’s Skwala Stone

Available through

This pattern one of my favorite stone fly patterns. You can purchase in on-line.

Dry Patterns

I have found photos of various Skwala Dry Fly patterns. I do not have the recipes. Some of these flies wre available online bit I should note that you will be able to better match the Lower Yuba Skwalas if you tie your own. A mentioned earlier catch a dry Skwala specimin and match the coloration and size.

Hogan's Split Wing Skwala Stone

This Hogan Brown Pattern has been proven on the Lower Yuba.


This pattern was developed by Randall Kaufmann.

Credit for the Stimulator’s design is often given to master fly tyer Randall Kaufmann, who promoted the fly heavily in the western United States.

Kaufmann’s Olive Stimulator is a perfect imitator of that, limited, but often highly productive early season hatch of Skwala stoneflies. With its subdued olive floss body, stiff elk hair wing, and supportive hackle, this fly will ride neatly and visibly on the water’s surface – just where those hungry Montana and Washington trout want it.
Note: The colors of this pattern should be adjusted and matched to the colors of the Lower Yuba Skwala.


This pattern used elk hair for floatation, rubber legs for movement, Light elk hair for visability.


I like how this pattern is tied very sparse. It looks like it would be easy to cast.


This is a foam pattern that should float like a cork.

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Have any Questions or Comments? Let me know, Clay.