Scuds are small, semitransparent, shrimplike freshwater crustaceans that, when dead or crawling around on rocks, look much like curled-up sow bugs, often taking on an orange tint when they first die or are pregnant with orange egg clusters. Taxonomically, their order is Amphipoda, and they are related to shrimp, lobsters, and crayfish, are widely distributed across many waters, and are extremely abundant in some. They exhibit a variety of colors, but dark olive, tan, brown, and gray are most common. Scuds are chameleonlike and can change color depending on the color of the background. They are a high-energy food source and a major part of the food chain for fish of many species, as well as for other creatures that depend on the aquatic environment for their food supply, including ducks and grebes.
The smallest may be only 5 millimeters long or shorter, and the largest 20 millimeters, which equates to approximately five-eighths of an inch. Even if some species are quite small and difficult to replicate with a fly, these are a food source for the juveniles of many species of fish throughout the year. Scuds can provide in excess of 40 percent of a trout’s diet. Where can you find large populations of scuds? Generally speaking, in slow-moving spring creeks, in tailwaters in calcium-rich, often volcanic drainages, and in high-desert lakes. Such waters are often trophy fisheries. Populations are relatively low in acidic alpine lakes, but can exceed thousands per square meter in the alkaline waters that characterize high-desert lakes, most of which are found in or on the borders of the Great Basin. It’s because of the high calcium carbonate concentrations in these alkaline waters, which foster plant growth and insect and crustacean exoskeleton development. All are important in rich fisheries that exhibit rapid fish growth and large fish biomass counts per acre. These are the lakes that produce monster trout.
East of the Sierra Crest, Crowley Lake, in a calcium-rich drainage, has scud populations, but from my experience they are not of great importance for the angler, compared with the midge and perch populations in that lake. Kirman Lake, a trophy brook trout lake off Highway 108, and Heenan Lake, the Lahontan cutthroat brood lake east of Markleeville, lying in the more alkaline soil of the eastern Sierra, have significant populations, and scud patterns can be very productive there. Lake Davis and nearby Frenchman Lake have populations, but they are mostly seen as incidental food in trout stomach samples. Perhaps we should fish them more there, particularly inshore, early and late in low-light conditions and before the weeds get too high.
Scuds are present in Pyramid Lake, the largest remnant of ancient Lake Lahontan. Pyramid is a strange lake in that fly patterns of all kinds take fish. I suspect that the presence of scuds there is of great benefit to the young cui’ui, a forage fish that is important to the lake’s cutthroat populations.
However, Eagle Lake is the scud capital of California. The lake lies in a transition zone between the northern Sierra and the southern Cascades. Volcanic geology and high-desert alkalinity provide the concentrations of calcium carbonate conducive to scud populations. Eagle Lake also mostly has gently sloping banks, shallow shoals, lots of weed growth, and volcanic rock piles, all of which promote dense scud populations.
The species Gammarus lacustris is the dominant scud at Eagle and can be more than half an inch long, a nice morsel for a feeding Eagle Lake–strain rainbow trout. Another species of scud of value to the fly fisher there is the smaller Hayallela azteca. There are also true freshwater shrimp in the lake. The dominant forage fish at Eagle is the tui chub, and I suspect that it also feeds on the shrimplike creatures that turn plant material, detritus, and small invertebrates into protein. Trout there have the best of two worlds in that they use both creatures in building body mass.
As you go farther north, as a general rule scuds get larger, as do midges, and become more important in northern fisheries. Eastern Oregon and Washington have many desert lakes, including Dry Falls and Chopaka Lakes. In eastern Oregon, there is Chickahominy, a reservoir, and Mann Lake, another cutthroat brood-stock lake lying at the eastern base of Steens Mountain. The Blackfoot Lakes east of Glacier National Park and the Canadian Kamloops region are famous for their scud populations and trophy trout fishing. In the Blackfoot Lakes, Eagle Lake–strain rainbows thrive. In the scudrich Kamloops, it’s the original Kamloops strain of rainbow trout, known for its leaping tendencies.
My first experience with scuds was on the mineral-rich Bighorn River, a prolific tailwater fishery that flows out of Yellowtail Dam just above Fort Smith, Montana. Trout populations in this river can range from seven thousand to twelve thousand fish per mile. It is known for massive hatches of mayflies, caddisflies, and midges. My partner and I had spent a successful guided morning drifting midge pupae on the soft insides of bends, moving our drift lanes gradually out into progressively deeper water as the sun rose higher in the sky. We took a lunch break on the edge of one of many gentle riffles, water different in character from the inside seams of the morning where we had done so well with small black and copper Brassie patterns that imitated small, drifting midge pupae.
I was eager to fish after gulping down a great streamside lunch. Our guide suggested a tan scud drifted through the riffle while he cleaned up. It turns out that in streams, scuds will at times drift with the current and become very vulnerable. I had a hookup on my first pass and subsequently took my largest fish of the day on a simple plucked-out dubbed-body tan scud pattern.
Several years later, another partner and I journeyed to the mineral-rich Blackfoot Lakes — for the most part treeless lakes located in wheat country in the high plains on the Blackfoot Indian Reservation. We fished with friends Denny Rickards and legendary guide Jay Fair and his son, Glenn. Our best pattern was Denny Rickards’s Stillwater Nymph. I had tied a version of this pattern on size 14 and size 16 hooks using Denny’s guidelines and Jay’s fiery orange dyed saddle hackle to simulate the orange egg clusters seen in scuds three or four times a year during their reproductive cycles.
Air temperatures were very cold the first week in May, and we lost no time removing our boots and waders after fishing. A day later, a strange fishy odor overtook us when we turned on the rental SUV’s heater. We found hundreds of dead scuds in the creases of our waders and boot seams and more on the floor. The little olive-colored, light-hating devils had sought out the dark creases in our underwater gear. That night, we stopped at a Cut Bank K-Mart to buy an inexpensive “scud brush.”
At night, Jay Fair talked about fish behavior in Eagle Lake when they are feeding on “shrimp.” He said that two-to-three-pound fish work in small groups, but that the larger four-and-five-pound fish are solitary soldiers and much more wary. The smaller fish are competitive, and sometimes that leads to their being hooked. Jay told us never to skimp on the length of the marabou tail in Denny’s pattern, because it makes a huge difference. The animation it imparts says, “This is a living creature.”
One secret passed on by Jay is to tie in the saddle hackle tips that palmer the dubbed body by tying in the rounded hackle tip at the tail end and twisting and stroking it a lot before spiraling it forward. I don’t see this in commercial patterns. It makes the hackle fibers lay back at an angle. Next, trim the dorsal or upper fiber tips and pull the marabou tail fiber stems tightly forward as a back. The ventral hackle fibers simulate the seven pairs of scud legs seen on all species, and the result just looks downright buggy.
We ran out of the successful Stillwater Nymph patterns and had to go to a K-Mart in Cut Bank again to buy a cheap extension cord, then tie Stillwater Nymphs late into the evening. We used the stripped extension cord copper wire for the ribbing. The copper helps imitate the rich orange of the egg clusters and adds a little weight. I had brought a fiery orange saddle neck.
After four days, we moved south to Battle Mountain, west of Choteau, to fish the Salmon brothers’ five Kamloops-strain lakes and film a segment of the then new and now defunct On the Fly TV fishing show. Battle Mountain was a small private lodge on seventy thousand acres of a five-generation cattle ranch near the original north-south Native American migration trail. In the evening, after dinner, Jay helped me tweak my Stillwater Nymph patterns. To this day, it is my most successful lake fly. It is as generic as it gets, imitating damselfly nymphs, Callibaetis nymphs, scuds, small leeches, and who knows what else.
I called an old Battle Mountain phone number a few years ago when I did an article on private still waters. I was doing a fact check and wanted to see if they were still in business. A caretaker answered in a gravely voice. He talked for awhile and told me that a “Mister Letterman” had bought the property and it was no longer owned by the Salmon brothers.
I learned a lot in those after-dinner tying sessions at Battle Mountain, where bison grazed the hillsides above the lakes. We also caught lots of Kamloops-strain trout. I was so enthralled by the experience and the huge trout caught in Montana that a year later, I headed to Kamloops, British Columbia, looking for more megatrout. Again, Denny Rickards sent me in the right direction, putting me in touch with the renowned guide Gordon Honey. Gordon was station manager at the local Kamloops television station when communications magnate Rupert Murdoch bought it and added the station to his empire, and Gordon was out of a job. His friends suggested that he follow his passion and guide for a living. Since then, he has become a fishing entrepreneur, owns a lodge, and does many instructional and educational fly-fishing videos. He’s booked a year or more out and gets clients from all over the world.
A highlight of several days in the Kamloops with Gordon was a day fishing Trojan Pond on a mine property, perhaps the ugliest lake that I have ever fished, but easily one of the biologically richest I’ve ever visited. Gordon’s wife set up the visit, and I threw several cameras around my neck over a safari jacket, posing as a San Francisco Chronicle reporter wanting to do an article on the mine’s conservation mitigation efforts. We bluffed our way in and had a fabulous day.
The 60-acre mitigation lake was built out of crushed mine rock tailings that release large amounts of calcium carbonate. The lake had no real all-season tributaries, but spawning channels had been built so gravid females can deposit their eggs in springtime and avoid being egg bound, which often means death. Gently sloping shorelines were covered with grayish marl, which is a mixture of sediments with clay and calcium components.
Shallow lake-edge bottoms were covered with chara plants, an alga that scuds love. The light-grayish, flat-leafed vegetation looks like miniature arugula leaves. On first glance, little life was apparent, but when the plants were disturbed, thousands of scuds darted about in frantic, erratic evasive movements. Trout grown huge on a diet of these creatures then darted about to find the scuds. They rooted around with their dorsal fins and tails out of the shallow water, at times tail down and at others cruising, looking for the small morsels, feeding at the trough. They were easy to spot. How did we interest these trout when there were thousands of scuds about? We tossed light-colored Kamloops Leeches, which are hackleless Woolly Buggers — basically a chenille body and a marabou tail. The rooting fish turned on the splash.
A year or two later, a partner and I were fishing recently filled Frenchman Lake. He solved the riddle of what the fish were eating that day by tossing a white Simi Seal Leech into stands of flooded reeds along Snallygaster Bay. A trout autopsy revealed a stomach full of scuds and a few small whitish leeches.
Scuds abhor light and are best fished in low-light conditions such as early and late in the day and on cloudy days. Commercial fly patterns are mostly tied on curved “scud” hooks, but scud bodies extend horizontally in swimming, even though they move erratically, to say the least. Use a regular straight-shanked nymph hook to imitate the correct profile. Many fly patterns work well as scuds.
I’ve mentioned that one of my favorites is the Stillwater Nymph tied in many colors. Another is a picked-out Bird’s Nest, and of course Jay’s Wiggle Nymph in the fiery orange color. Fish them on long leaders in shallow water with a herky-jerky, erratic retrieve with lots of pauses.
Scuds are one more aquatic creature that illustrates the complexity of the stillwater fly-fishing game. They inhabit many waters, fish eat them with abandon, and they can be imitated by the fly fisher with a few simple patterns. Lie down at water’s edge someday and take a long look at what’s beneath the surface. You may be surprised by what lives there.
