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All About Tricos

Vince Marinaro, wrote about the Trico hatch in In the Ring of the Rise, called the size 22-26 mayfly the 'white-winged curse,' due to it causing selective feeding.

Male Trico duns hatch during the night and females hatch in the early morning before the mating swarm occurs. Photo: FFM Staff

From Pennsylvania to California and on many productive trout waters in between, the Tricorythodes hatch is the best mayfly hatch of the summer. No other hatch brings as many trout to the surface in July and August, but no other hatch leaves as many anglers scratching their heads or shaking their fists at the water in despair.

Vince Marinaro, who first wrote about the Trico hatch in his book In the Ring of the Rise, called the size 22-26 mayfly the "white-winged curse," because it caused such selective feeding. Pennsylvania legend George Harvey made the study of Trico hatches and trout-feeding behavior a lifetime pursuit that continues today. He found that trout become so selective during the Trico spinner fall that in the early stages, they will only take imitations of the female spinner and later they feed exclusively on males. Harvey called it "the most important hatch" because if you can catch trout on Tricos, you can easily master other hatches.

The challenge of the Trico hatch continues to attract the attention of anglers looking to pass the ultimate angling test of knowledge and skill. From these anglers' efforts, we know Harvey's revelation is just one part of the Trico puzzlea picture that becomes clearer and more informative as each new generation of experts tackles the Trico "problem" on their local waters.

To help you learn these new discoveries, we've interviewed five of the best anglers and fly tiers in the United States and share their new tactics and fly patterns that will help you catch more fish on the top Trico waters in the country. The Trico hatch will never be easy but with tutors like these, you should get top grades the next time you take the Trico test.

Trico Identification

There are three main species that are important to North American anglers: T. minutus, which hatches across the country, and T. stygiatus and T. allectus, which are most prevalent both in the East and Midwest. T. minutus is slightly larger than the other two species but because of their similar appearance and life cycles, there is little need to distinguish one from another.

Trico duns and spinners range in size from 3.5 to 6.5 mm and can be imitated with size 18 to 26 hooks. They are the only small mayfly you are likely to encounter during the morning hours of the summer and are easily identified by the lack of a hind wing. Tricos are sometimes confused with White-winged Sulphurs from the Caenidae family, which also have no hind wing, but these insects usually inhabit warmer, slower waters and most often hatch in the late afternoon and evening.

Mike Mercer Knows Tricos

Mike Mercer works for The Flyshop in Redding, California, and fishes the local Trico hatches on Hat Creek and the Fall River. The hatches start in mid July and end in September.

During the morning hatch of female Trico duns, the trout feed aggressively on individual insects and are much more likely to move side to side to take a fly. During the spinner fall, the insects are so thick they sometimes form mats on the surface of the water. The trout feeding lanes become so narrow that you practically have to cast your fly into an open mouth.

"It can be overwhelming for a novice angler because you see so many fish, so many bugs, and yet get no grabs," says Mercer. "It's very frustrating."

Mercer says that if your casting is accurate to within inches, you can catch dozens of fish during the spinner fall. If your casting is not up to snuff, it pays to get up a little earlier and be there for the hatching female duns.

Mercer believes accuracy and presentation are the most important elements of success during a Trico hatch and uses the same fly through all phases of the hatch. Whether it's male duns in the late evening or female spinners in the morning, he uses a parachute Trico imitation with spent Z-Lon wings and a hot orange parachute post.

Get up early to find the hatching female duns--it is often the easiest fishing of the day. Photo: FFM Staff

Mercer says he can see the fly better than traditional patterns which helps him direct his casts more accurately. Although the insects on his local waters are normally size 22 to 24, Mercer uses size 20 to 22 imitations, both for better visibility and a larger hook gap to hold fish.


George Anderson Knows Tricos

George Anderson owns Yellowstone Angler in Livingston, Montana, but chases the Trico hatch around the state. His favorite Trico waters are the Bighorn and Missouri rivers. The Missouri seems to have just one generation of Tricos, with dense hatches starting mid July and lasting into early September. Just about when hatches on the Missouri are tapering off for the season, a second generation of Trico hatches is getting started on the Bighorn. On the Bighorn there are often good Trico hatches through October.

On these rivers the Trico spinner falls are often so heavy that the trout can open their mouths and inhale rafts of insects. Since they are not dining on individual insects, they rarely move to take a fly. Therefore accuracynot pattern selectionis the key to success. The spinner fall often lasts only from 30 minutes to an hour, which makes for a short, intense, and sometimes frustrating experience. Anderson says the spinner fall is a spectacle but often the hatch is more productive because fish are willing to move to take a fly

Anderson's all-time favorite Trico pattern is a thorax dun imitation. He fishes it one size larger than the hatch on the water and uses it for both emerging duns and the spinner fall. On the Bighorn and Missouri the insects are usually size 22 or 24, but he fishes a size 20 or 22 pattern because it stands out better on the water. If after repeated accurate casts a trout doesn't take the patternand there aren't other more willing targetshe switches to a René Harrop Biot Spinner with spent hen wings. Anderson says many trout feed on drowned Trico spinners, so he often hits the water hard with this fly to break the surface tension and drift the fly just under the surface. Anderson says he has never seen fish distinguish between male and female spinners.

Kelly Galloup Knows Tricos

Kelly Galloup is an author, guide, and former owner of The Slide Inn on Montana's Madison River. Researching his book, Cripples and Spinners, has allowed him to pursue Tricos throughout his home state of Michigan, the Midwest, and Montana.

According to Galloup, the hatches on two of his favorite Trico waters, the Au Sable and Manistee rivers, start around 5 A.M. in July. As the hatches progress, they get a little later each week until September, when you can have Trico hatches as late as 9 A.M.

Because of the short hatch period, Trico duns play a less significant role than the spinner, and Galloup places more emphasis on the spinner.

"Around here the females are more important than the males, possibly because the contrast of color between the abdomen and the thorax is a keying-in point."

Kelly believes a common mistake anglers make is that they rely on matching the colors of a natural rather than the relationships of size and shape. Most Trico patterns are not tied in proportion to a natural. The size and span of a natural's wings are considerably larger than the body, but tiers commonly use small clips of material to represent wings. One solution he recommends is to replicate Ellis' Triple Wing Spinner and use several strands of material to make the wings appear wide and long.

The effectiveness of fishing a Trico nymph during a spinner fall gave him the idea for the Galloup Sunken Poly Spinner. Once the spinner fall begins to yield, Kelly drops this pattern from a Compara Spinner or Trico Spinner pattern and fishes it on a swing or high sticks it through riffle water. He says the advantage to using this technique is that fish are less selective under the surface and he is able to use larger patterns, heavier irons, and aggressive presentations since drag isn't as much of a concern.

"I like Triple Wing Spinners in sizes 22 and bigger, but sizes 24 to 26 are what I use for Double Wing or Compara Spinners."

Male Trico spinners fall to the water only after the females have mated and laid their eggs. When fish are feeding selectively on individual insects, it's important to fish the female spinner first and use the male spinner during the last part of the spinner fall. Photo: FFM Staff

Charlie Meck Knows Tricos

Charlie Meck lives near Spruce Creek in Pennsylvania and the Salt River in Arizona, an arrangement that allows him to fish Tricos six months of the year. Tricos show up on Spruce Creek and other Pennsylvania waters such as Falling Spring and Spring Creek in late July and can last until early November. On the Salt River, the Upper Verde at Cottonwood, and Oak Creek near Sedona, Arizona, Meck looks for Tricos around March 1; they last until December.

Meck believes it's important to understand the life cycle of the Trico to understand how to fish Trico patterns effectively. You don't use a Trico imitation in the winter because the natural isn't present at that time. And, you wouldn't bother fishing or tying a male Trico dun because the adults emerge at night. Also, you can anticipate when the spinner fall will occur by watching the mating swarm. Finally, when the spinner fall occurs, use a female spinner imitation first, then switch to a male spinner toward the end of the spinner fall.

Female duns and spinners are olive, but all the spinners that fall on the water are creamy-white, because immediately after fertilization in the air, the female exudes her dark olive eggs and carries them in an egg sac at the tip of the abdomen. Once females have been mated in that swarm, they drop eggs or release them immediately upon impact with water.

Meck sometimes fishes a white-bodied female spinner with one turn of olive at the bend to suggest this egg sac, but most often uses an imitation with a body that is entirely creamy-white with a robust, dark brown thorax.

For adults, Meck likes a simple #24 dun pattern with a pale olive body, paledun hen hackle tip wings, and pale-dun hackle, with tails about the length of the body. Female duns' tails aren't as long as the male spinners', which can be almost twice the length of the Tricos' bodies. During a heavy spinner fall, Meck often fishes a spinner imitation 2 to 3 feet behind a #18 Patriot.

The pattern Meck fishes 70 to 80 percent of the time is the Sunken Trico Spinner, which he has been using to fool Tricos for more than a decade. He adds wraps of weight to the thorax and uses angora or possum rather than poly for the body to help the fly sink. He uses a #18 Patriot as an indicator fly. Meck says that during and after a spinner fall, "Trout stay underneath and feed on sunken Tricos. Female spinners fall upstream, where they've traveled to lay their eggs, and some get submerged going through riffles."

John Barr Knows Tricos

John Barr's Trico testing grounds are the hard-fished waters of the South Platte, primarily the Deckers and Middle Park (between Spinney and 11-Mile reservoirs) stretches in Colorado. Here, Barr says, you can always find fish feeding on Tricos. "I caught my ten biggest trout on dry flies in this section and five fish over 20 inches on Tricosbig, beefy browns. Trico fishing here starts in July and goes into October, and it is a totally predictable phenomenon. Once they arrive they are there every day."

The secret to Barr's success is the sunken spinner he developed. "Fish are more pressured these days; with a Sunken Spinner it's easy fishing."

Barr ties his Sunken Spinner on a TMC 2488 hook. This 2X heavy hook is 3x wide and 2x short, so on a #18 hook you get the bite of a #14 and the length of a #22. He says, "You can actually play and land fish on this hook. This is very important. With a standard hook you don't have the hardware to handle a fish."

Barr fishes his Sunken Spinner 6 to 8 inches below a #20-22 poly-wing dun he calls the Vizabaetis, which has a split tail, Comparadun-style flared poly-wing, and a hackled thorax.

"One thing I've learned in Trico fishing is that if you are using only a spinner, you don't see it well. I started using a dun/spinner combo so that I could see and monitor my drift. You won't catch trout fishing your spinner as a 'living insect.'" When I use a Sunken Spinner I use fluorocarbon.

Barr feels that the most overlooked but important aspect of Trico fishing is the post-spinner fall fishing when trout are taking Tricos that have sunk under the surface. After a heavy spinner fall when the fish have been gorging, Barr heads for the riffles for one to two hours of Hopper, Copper, and Sunken Trico Spinner fishing.

For male and female spinners, Barr uses a simple black spinner imitation with a poly-wing and a dubbed body tied on a TMC 101. A floating Trico pattern needs to float well and have high visibility. For that reason, he doesn't like quill-body patterns because they don't float well.

To improve his odds in a blanket hatch when he is not fishing a sunken spinner, Barr makes lots of casts and gets close. "I've caught most of my fish at 15 to 20 feet."

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