Scuds. It's all about scuds
Think scud ... catch fish. Of all the insects out there, fly fishermen should be getting up close and personal with scuds, more than any other insect species. If you are into mayflies, you need to worry about all those life cycle changes that a mayfly will go through. You have the egg, well I have never fished a mayfly egg pattern, the nymph which could be a swimmer, a burrower, a home wrecker or a who knows what. Then there is the hatching mayfly, the semi-hatched mayfly with a twist of lemon, the emerged mayfly, the adult mayfly, the quasi-adult mayfly with a touch of adolescence, the dun, the nearly dun, the could have been a dun, the spinner, the knitter, the spinster, the crippled mayfly, the once crippled mayfly but due to a chiropractor I am fine mayfly, and on, and on, and on. It's little wonder that some folk turn fly fishing into a nightmare rather than a fun sport. Now as for your scud ... they swim, they breed, they swim, they eat, they swim and they get eaten by a fish. So with scuds there is much less to worry about if you are trying to copy the various parts of their life cycle. The newly hatched scuds look just like miniature versions of the adult scuds. The young scuds will molt about 10 times before they become fully grown, and then as adults they will continue to molt. Adults can lay 5 or 6 batches of eggs per year producing over 15,000 eggs. In other words, there are a lot of them around.

More about scuds
Give or take a few, there are about 90 species of scuds in North America. If you want to get all scientific, the set up is:
Class: Crustacea
Order: (Fries and a pop) Amphipoda
Family: Gammaridae

Out of all the different species of scuds, Gammarus is the one that most fly fishermen should take a second look at and become familiar with. Get to know them on a first name basis, maybe even take them out for a movie on the weekend. They are your friend, but you just don't know it. Yet. Gammarus are important because they like to live in shallow water, (12 feet or less) which makes them an easy target for trout. Most of them can be found in water that's less than hip-deep and which holds thick vegetation. Keep this in mind the next time you are fishing off the breakwalls for steelhead. Scuds like to hang out in the water close to the breakwalls as the rocks can provide hiding places, and the plant growth around the breakwalls, provides food. All Amphipods, not just Gammarus love to eat and that plant growth will keep them close to the breakwalls.

How important are scuds?
In some watersheds, suds make up to 20% of a fish's diet. Some trout can pack on over a pound per year in waters that have a high scud population. I dunno about you, but I would say they are a pretty important food source.

"I tell you wot!"
As they say in Arkansas, "I tell you wot." In some locations in Arkansas, the guides stalk large fish in the shallows using small scud patterns. I have tried it and it's heart stopping stuff. And, after a triple by-pass I know about heart stopping. One nifty scud-fishing pointer I picked up down there was never to cast a scud at a tailing trout. Here's why, and this holds true for other watersheds not just the White River and the Norfork River. Scuds like to hang out in weed growth. When trout try to dislodge them, they will "tail up" and root around in the weeds. Then they will return to their normal feeding position of "tail down," to scarf back the dislodged scuds, which at this point in time must be pissed-off no ends. Not only are they out of a home, but something is trying to eat them. Unnerving to say the very least. I was told that if you cast to the trout when they are "tail up" they won't take your fly as they are far too interested in rooting around. However, once they go "tail down" they are now feeding on the dislodged scuds. It's only a thought, but that's when you probably want to drift a scud fly past them.

The Arkansas Sowbug Roundup
Then there is the Sowbug Roundup, a great fly tying get together held not far from the WAPSI fly tying materials world headquarters in the town of Mountain Home, Arkansas. Held every March, the three day event is put on by the North Arkansas Fly Fishers. With over a hundred tiers in attendance, and only a $5 entry fee for all three days, the Sowbug Roundup is not to be missed. I must say that the folk attending the Sowbug Roundup are just as picky about the curve on a hook, or the subtle shade of a scud dubbing blend, as any finicky dry fly purist is about picking a top notch dry fly hackle. The Sowbug Roundup is not just about sow bugs, the scuds get a good working over as well. Isn't it funny how the words "finicky dry fly purist" go together so well.
Sowbug Roundup, learn more ...

Even more about scuds
Quite a few fly fishermen often refer to scuds as freshwater shrimp. Although they are related to shrimp, they are not shrimp. In any grocery store you can pick up a shrimp ring, but I have yet to find anyone selling a scud ring. The difference between them is that scuds have their 14 legs set as pairs all along the lower body. Shrimp have three distinct sections and their legs are more packed together near the head. The easiest way to tell is to pick them up. Scuds will curl into a curve shape, but shrimp will try to spring away from you.

Scud sizes
Scuds range in size from just over half an inch down to about one sixteenth of an inch. I find that for most of my fishing sizes #12 to #16 are a safe bet. Even steelhead and smallmouth bass will have a whack at size #12 or #14 scuds, so there is not much need to tie up a bunch of size #8 scuds nor size #22 scuds.

Scud colors
This is neat stuff. Scuds are pretty much transparent little creatures. They take on their colour from the stuff they have eaten. What you actually see is the coloration in their intestine. I kid you not. So, scuds that are feeding on dark olive plant matter will have a dark olive hue to them, those that at munching down on tan items, will in turn have a tan hue about them. If the scuds are chewing down on Chinese food, you can guarantee they will be back on the feed in less than an hour. Actually if you think about it, taking on the colour of your food rather smart. If you take on the colour of the stuff you are eating, it sure as heck is going to camouflage and hide you from your predators. Many anglers believe that scuds are herbivores or veganivores content to graze on weeds and plants, but they are not. They are omnivores and will have a go at just about anything that comes their way including dead fish. They will pack-up and bring down water boatmen, midges and smaller insect nymphs like damselflies. One can only imagine the underwater horror of a pack of marauding scuds when the bloodlust is upon them.

Yellow scuds
As scuds get older, most of them only live for a year, they then start to take on a yellowish colour. They don't seem to be able to take on the olive and green colours that they could when they were in their younger and adolescent years. This is actually a helpful thing to remember if you are imitating a scud. There is little point in tying up small yellow scuds because for most of the time when trout see a yellowish scud it will be a larger insect.

Orange scuds
In the 1990s John Roberts, the noted English fly fishing writer, introduced me to a scud pattern with a bead in the middle of the body and scud pattern with a bright orange turn of dubbing in the middle of the body. He did not invent them. They were used for grayling fishing. I could see the point of the bead, as scuds live down on the riverbed, and I figured that the orange dubbing was there as a hot spot. Something bright to get the attention of the fish. Not necessarily so. John went on to tell me that there is a parasite Pomphorhynchus laevis which lives in the intestinal tract of a scud and which turns the intestinal tract orange. Fish key in on this. Why orange? The scud is simply the intermediate host for the parasite. It actually wants to end up living in a trout, barbel (Barbus barbus), bream (Abramis brama), goldfish (Carassius auratus) or chub (Leuciscus cephalus). So by turning the scud bright orange the trout can easily see it. The trout woofs down the scud and the parasite ends up where it wants to be ... inside the trout. Darn cunning. Sometimes you will find dead orange coloured scuds in the water or inside a fish. Orange is not the colour of a live scud, it shows up when the insect dies. The orange colour is carotene and when ingested, the carotene is transferred into the tissue of the fish, and the flesh takes on a nice reddish-pink colour. Those reddish-pink fillets sure look good sizzling in the pan with some butter, lemon, pepper and chives ... Also, when they are pregnant, the egg sack in a female scud turns bright orange. I have no clue as to why that is.

Pregnant scuds
Scuds mate from late spring, when the water warms up, through to the late summer or early fall, when the water starts to get too cold. As my good friend William Gerrard pointed out, the fall would be a good time to fish a pregnant scud, with the orange spot, as the aquatic vegetation starts to die down. This helps to make the scuds more visible to the trout. Nice one William!