Olive Scud fly fishing freshwater shrimp pattern takes trout and grayling. Why? It is because one mating pair of scuds can produce upwards of 7 broods, totaling 20,000 offspring per year under ideal conditions. The fish hunt them for food.

SCUD FLY PATTERNS. (also a great freshwater shrimp or louse imitation) Hook size 14 16 18 - $US each

Scudding is the common term used to describe the darting and swift swimming habits of this freshwater shrimp-like creature. From the term scudding they get their name, Scud. Their other name is the Mussel shrimp or Ostracoda. Scuds are members of the class Crustacea, order Amphipoda. Scuds' are distant cousins to the crayfish, sowbugs and shrimp. The beauty of fly fishing with scud imitation flies is that you can use them at any time of the year. They are always available as food for fish even when other insect availability is limited. They are an ideal pattern to use during those non-hatch periods of early spring, late Fall/Autumn and low light conditions of very early morning and late evening. Scientists have identified over 90 different species in the fresh waters of the USA.

There is a greater diversity of scud species in the Midwestern and Eastern states compared with the Western states. They are good general shrimp patterns for catching fish all over the world. Newly hatched young look like smaller versions of the adults. As the young grow they molt their skin (exoskeleton) five to nine times before reaching adulthood. Adults continue to molt another 15 to 20 times during their life as they grow. The time periods between molts can be anything from three days to around 40 days. It depends on the species, availability of food and water temperature. Most species mate and lay eggs anytime between spring and late summer one to fifteen times in the same season. The frequency depends again on the species, availability of food and water temperature. The normal life span of a scud is normally one year but they can live for two years.

A number of anglers use the term 'shrimp' when they mean scuds. If you look closer scuds differ from their distant cousins. Scuds have the appearance an armadillo: hard, segmented exoskeleton with seven pairs of legs carried underneath the body. The front two pairs of legs are used for grasping while the remainder are used for swimming. These legs enable the scud to swim quickly at times, although they commonly move in an erratic and random manner. Some species prefer moving around in an upside down fashion. Scuds also have 2 pairs of antenna. Located between the various pairs of legs are their gills. Scuds spend their entire life beneath the water's surface. There is no pupal stage or emergence of any kind.

One mating pair of scuds can produce upwards of 7 broods, totaling 20,000 offspring per year under ideal conditions. Scuds mate in a piggyback like fashion with the female usually on top. They are omnivorous feeders, eating just about anything. Scuds even attack larger aquatic insects such as damsel fly nymphs and water boatmen in Piranha like fashion, but they seem to prefer a vegetarian diet. Scuds are capable in living in depths as great as 50 ft, but prefer shallower depths of 15 ft or less. Scuds are light sensitive and are most active in low light overcast conditions. These are good days to fish a scud pattern. Scuds take refuge from the light in large numbers under boats and other shady areas like piers.

Scuds come in a wide range of colors. A good rule of thumb is, darker the water the darker the coloration of the scuds. Translucent scuds has a chameleon like quality. During times of low weed growth the scuds will be pale in color. As the weeds grow, scuds are able to change color to match their surroundings. Scuds lose the ability to camouflage themselves effectively as they near the end of their lives. The coloration tends to become various tones of yellow. Scuds with an orange colored spot in the middle of their body, are pregnant females. The orange spot is the brood pouch, or Marsupium. In some Trout stomach samples you will see orange colored scuds. This is not their natural color. When a scud dies the natural coloration disappears, the orange color is due to the presence of Carotene. Carotene transfers to the fish during the digestive process and leads to the beautiful pink flesh.

Using Shrimp flies on Stillwater

Fish in still water are just as finicky as their river cousins but in the opposite way. When there is no current to move your artificial fishing fly the fly fisherman has to impart movement to arouse the fish’s interest.

Think how a freshwater shrimp moves. Being a relatively small invertebrate it moves in very small spurts. This can be imitated with a series of small, sharp jerks or an erratic figure-of-eight retrieve. Whichever you choose, stick with the winning method when you start to get takes.

Try varying the speed and length of the strokes to obtain some interest. Remember that no shrimp moves systematically in a perfect fluid motion. They appear to dart as if they are constantly under threat of being eaten. They try to give predators are hard time trying to catch them by not being predictable in the way they move.

So how do you work out what type of freshwater shrimp pattern to use? The best way is to find examples of the local resident population. You can do this three main ways. You can spoon a fish to find out what it has been eating or simply turn over a few rocks in the shallows and have a look. I prefer using a net on a long pole and dragging it along the water bed to see what is lurking. A child’s fishing net works very well and they are very cheap.

During the Shrimp breading season the males change colour quite dramatically and if you are not aware of what is happening down below in the depths you will be at a disadvantage. Even if you fish the same water again and again and you know what pattern matches the local fresh water shrimp it is still worth while using a net or looking under rocks to see if the males have changed colour.

Some male shrimps form a bright orange hue in the centre of their bodies. Miss this colouring in your shrimp imitation fly and you will miss out. The trout seem to home in on the orange trigger colour and it is essential to use a fly that imitates a male shrimp in its breading finery. I always carry a range of waterproof permanent marker felt pens in a range of colours in my fishing bag. If I do not have the correct coloured fly I will use an orange marker pen and change the markings on my shrimp fly to reflect the local male shrimp’s body colour.

Shrimps love water with a high oxygen content. Look for an inlet pipe or feeder stream when you are next on the bank. Cover this area with a shrimp pattern and you will probably be rewarded with a take.

You can get some very effective presentation using a buoyant Booby Nymph on point. Using a fast sinking line construct a leader with two droppers: the first no more than 2 feet from the fly line and the second about 4 feet. Fix the Booby Nymph about 3 feet from the second dropper on the end of the leader. This is called the washing line rig.

For this method to work effectively it is best to use unweighted shrimp fly patterns. Cast this out and allow the flies to sink. Fish the team with short, fast, jerky pulls but pause for a few seconds in between each pull.

This has two effects on the flies. Firstly it moves the flies downwards in a diving motion. Then when you pause, the buoyant Booby Nymph lifts the fly in the water giving it a very life like motion. You also have the attracting attributes of the marabou tail and body of the Booby to stir interest in lurking hungry fish.

Facebook reader's comment

I went for some serenity before dark. I used some Scuds on Moses Lake feeder streams and I got to talk to some Rainbows as well. Escobedo

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