Olive Scud
There is a creature that thrives in aquatic vegetation that trout love to eat. It is not a dun or nymph. It is not a pupa or larva. It is not a spider or strider. It is not a fish or fry. It is not a hellgrammite or night crawler. It is not a crayfish or freshwater shrimp. However, it is a close relative of the crayfish. This creature is a scud!
Class: Crustacea
Order: Amphipoda
Family: Gammaridae
There are ninety species of Gammarus or scud in or North America. Gammarus are important to fly fishers because they live in shallow water no deeper than twelve feet and in most cases in only hip-deep water. In the right habitats with heavy aquatic vegetation, they can provide up to twenty percent of a trout’s diet. Trout that have scud available in their diet may gain an additional pound per year. The presence of scud means that trout are likely to be on average larger than normal. Scud are found in abundance in higher pH waters such as spring creeks, tailraces and streams that capture nutrient run-off. In all cases, the aquatic vegetation is the key habitat.
Scud
Some fly fishers call scud a freshwater shrimp but this is not correct. A shrimp has three distinct body sections and its legs are all near the head with none in the tail section. A scud has fourteen sets of legs across the entire body. If you pick up a live shrimp, it will tend to spring out of your hand. If you pick up a live scud, it will tend to curl thus the logic behind using a curved hook. If a scud is drifting in a current, it may tend to curl if not actively trying to swim, otherwise, a scud observed swimming or clinging tend to be rather straight. So, scud fly patterns do not necessarily need to be tied on curved hooks.
Scud swim, they eat, they swim, they breed, they swim, they get eaten by trout. Scud are 100% aquatic, underwater always. Scud cling aquatic vegetation and to breakwalls as the rocks can provide hiding places, and the plant growth around the breakwalls, provides food to the scud. All Amphipods, not just Gammarus or scud love to eat foods available on plants so the plant growth keeps them near the breakwalls.
Adult scud can lay five or six batches of eggs per year producing over 15,000 eggs. The young scud molt about ten times then become adults that continue to molt. In other words, newly hatched scud are miniature versions of adult scud. Scuds range from size 12 to size 22. If you must, only tie one size, then size 16 will generally get the job done.
Prominent colors are gray, tan, green, yellow, cream and orange. The natural gray, tan and green shrimp are of various species in their adolescent and younger stage. As scud age, they tend to turn yellow and at post mortem, cream colored. Knowing this helps in sizing. Tie size 22, size 20 and size 18 in gray, tan or green. Tie size 12 in yellow. A scud may die at any age; thus, cream may be used from Size 12 to Size 22.
Orange or a band of orange are also variations for scud fly patterns. These color variations are important due a parasite Pomphorhynchus laevis that lives in the intestinal tract of a scud and turns part of the scud orange thus forming an orange band. The parasite uses the scud as a carrier to ultimately get into the intestinal tract of a fish where it completes its life-cycle, while all along feeding off both carriers. If a scud dies with the parasite, the entire scud turns orange in color. Scud that die without the parasite turn cream in color.
Another color variation is a scud fly pattern with a distinct orange spot or “hot spot” which imitates an egg bearing scud. Scud mate from late spring, when the water warms up, through to the late summer or early fall, when the water cools. The fall is the ideal time to fish the egg bearing scud as the vegetation dies down and the “hot spot” is very visible. In general, scud are active year-round. However, with more choices to imitate in the warmer months, scud fly patterns are a good choice during winter fly fishing.
Scud do not like bright lights, thus in general, a scud fly pattern is more effective during times of low light around dawn and dusk and during overcast days. Otherwise, scud fly patterns must be heavy enough to get down near bottom where scud hide away from any intense daylight. Scud are good swimmers, but they swim in short bursts of speed and in an erratic almost sideways manner. Your retrieve should be somewhat jerky and ready for a soft take.
Scud
Fly of the Month 2.17
- Tom Adams, Alen Baker
Hook: Curved scud style, standard length. Tiemco 2488 or equivalent, Size: 10, 12, 14 ,16
Thread: 8/0 Uni or equivalent to match color
Body: Spikey dubbing –three colors
Ribbing: 5/0 tippet
Back: 1/8 Clear or color scud backing
Directions :
1) Overwrap lead or lead free weight beginning about one third of the distance from the eye and continue to one or two wraps forward of the hook point. Keep wraps tight and push together if necessary.
2) Start thread wraps immediately in front of the lead wrap and using wide soft loops take thread to behind the lead and start building a taper of thread to trap the lead. Do not build up the taper completely but advance the thread over the lead without so much tension as to push the thread between the wraps. The taper toward the eye can be completed, but, do not crowd the eye. Bring the thread to the hook bend and let the bobbin hang. Note : it is not necessary to completely cover the lead with thread. Just enough to make dubbing easier.
3) Using a three inch piece of tippet, tie in where the lead stops and the taper begins and bring the thread back to the hook bend in tight secure wraps. You may use pliers to “mash” the tippet somewhat flat where it is tied in. This will help keep a thin profile. Let the bobbin hang.
4) Cut a two inch piece of scud backing and choose one end to cut two forty five degree angles to form a very short point. This will help in tying in. Tie the scud backing in at the same spot the tippet was tied in and after one or two secure wraps of thread on the tip, begin pulling the scud backing with slight pressure and wrapping back down the hook to the finish point of the ribbing. This will narrow the scud back, but do not make it so narrow as to not cover the dub on the next step. Move the backing out of the way.
5) Dub the thread and advance to forward of the lead and let the bobbin hang. The dubbing should be in three colors. One lighter for the abdomen in the color of choice. The second color is a “flash” color, and usually red, orange, pink or yellow. It is very narrow in width, about one of the segments. The third color is the thorax and is usually the same color as the abdomen but in a darker hue. Note: there are no steadfast rules and this can be a creative venture in the colorations.
6) Pull the scud backing over the dub. Note the coverage and by adding more or less pulling pressure you may cover or uncover the dub. The material when tied in should cover about half of the sides. Wrap the scud backing with two wraps of thread and let the bobbin hang.
7. Advance the tippet material in firm open wraps to imitate the segmentation of a scud. Tie in after making one wrap to bind the scud back and clip both the scud back and the tippet. Tie in tightly to avoid slipping. Do not crowd the eye. Cut the thread.
8) Use a permanent color marker to add interest and detail to the scud backing.
9) Using a bodkin or dub tool pull and loosen some fibers at the thorax to mimic legs.
10) Cement the head.
Thread: 8/0 Uni or equivalent to match color
Body: Spikey dubbing –three colors
Ribbing: 5/0 tippet
Back: 1/8 Clear or color scud backing
Directions :
1) Overwrap lead or lead free weight beginning about one third of the distance from the eye and continue to one or two wraps forward of the hook point. Keep wraps tight and push together if necessary.
2) Start thread wraps immediately in front of the lead wrap and using wide soft loops take thread to behind the lead and start building a taper of thread to trap the lead. Do not build up the taper completely but advance the thread over the lead without so much tension as to push the thread between the wraps. The taper toward the eye can be completed, but, do not crowd the eye. Bring the thread to the hook bend and let the bobbin hang. Note : it is not necessary to completely cover the lead with thread. Just enough to make dubbing easier.
3) Using a three inch piece of tippet, tie in where the lead stops and the taper begins and bring the thread back to the hook bend in tight secure wraps. You may use pliers to “mash” the tippet somewhat flat where it is tied in. This will help keep a thin profile. Let the bobbin hang.
4) Cut a two inch piece of scud backing and choose one end to cut two forty five degree angles to form a very short point. This will help in tying in. Tie the scud backing in at the same spot the tippet was tied in and after one or two secure wraps of thread on the tip, begin pulling the scud backing with slight pressure and wrapping back down the hook to the finish point of the ribbing. This will narrow the scud back, but do not make it so narrow as to not cover the dub on the next step. Move the backing out of the way.
5) Dub the thread and advance to forward of the lead and let the bobbin hang. The dubbing should be in three colors. One lighter for the abdomen in the color of choice. The second color is a “flash” color, and usually red, orange, pink or yellow. It is very narrow in width, about one of the segments. The third color is the thorax and is usually the same color as the abdomen but in a darker hue. Note: there are no steadfast rules and this can be a creative venture in the colorations.
6) Pull the scud backing over the dub. Note the coverage and by adding more or less pulling pressure you may cover or uncover the dub. The material when tied in should cover about half of the sides. Wrap the scud backing with two wraps of thread and let the bobbin hang.
7. Advance the tippet material in firm open wraps to imitate the segmentation of a scud. Tie in after making one wrap to bind the scud back and clip both the scud back and the tippet. Tie in tightly to avoid slipping. Do not crowd the eye. Cut the thread.
8) Use a permanent color marker to add interest and detail to the scud backing.
9) Using a bodkin or dub tool pull and loosen some fibers at the thorax to mimic legs.
10) Cement the head.