Mayflies provide a year-round food supply for the wild rainbow trout and steelhead that inhabit the cooler sections of California’s Central Valley rivers. That means you don’t have to make the long drive to Shasta or Burney or Mammoth or other higher-elevation streams to experience and fish a great mayfly hatch. In Northern California, three valley tailwaters that I know well — the lower Sacramento River, the Yuba River, and the Feather River — support multiple species of mayflies, and mayfly hatches regularly bring trout to the river’s surface, where, through skillful presentation, these fish can be tempted to take an imitative emerger pattern or a dry fly. Many in our sport consider this to be fly fishing at its finest. Moreover, the mayfly hatches of these rivers offer angling opportunities to fish mayfly imitations all the way through this elegant bug’s life cycle, from nymph to emerging adult dun and from dun to spinner. This article will emphasize the first three of those four stages — nymph, emerger, and dun. Although the spinner stage can likewise draw trout to the surface, it would be fair to say that the majority of fly fishers focus on the prehatch and hatch stages of mayflies. (Just so you know, spinners are duns that have gone through a second molt to become sexually mature. They have thinner bodies than their dun stage, transparent wings, and often different body coloration. Spinners mate in the air, after which the females drop their fertilized eggs in the water and then, spent, collapse on the surface). See page 31 for an illustration of the mayfly life cycle and a hatch chart for valley rivers.
The Valley Mayflies
Mayflies belong to the order Ephemeroptera. Take a look at that last word — mayfly adults are ephemeral creatures, meaning they do not live long, usually only a day or two (the underwater nymphal stage is much longer). There are over three thousand species of mayflies with over four hundred genera and 42 families. Fortunately, the only ones you need to know about are the ones in the rivers you fish, and in the lower Sacramento, Yuba, and Feather, there are just four major mayfly hatches: March Browns, Blue-Winged Olives (BWOs), Pale Morning Duns (PMDs), and Pink Alberts. As often has been said, trout don’t speak Latin, so to catch fish, you don’t need to get into the names of these bugs at the level of genus and species. You just need to recognize them when you see them. Note, by the way, that the coloration within a species can vary both by river and sometimes even by section of river. Try to snag a sample of the insect you want to imitate from the section of river you want to fish, then check its color before you tie on your fly.
March Browns are size 12 to 14. The dun’s body color is brown, tan, and different shades of black and gray, with tannish brown the predominant color. The wings are usually brown and tan. The nymphs are clinger mayflies — they can be found clinging to cobbles and larger rocks — and their flat, wide bodies help them cling there in the swift, highly oxygenated water they live in. The nymphs range from dark olive to different shades of brown, again in sizes 12 and 14. The emerger stage has the same colors throughout, from the nymphal exoskeleton to the emerging dun.
Most Blue-Winged Olives in valley rivers are size 16 and 18. The dun’s body colors are different shades of olive, with tans and browns mixed in. The wing is usually some shade of gray, not blue. The nymphs normally are swimmers, but lose that ability when they emerge and drift in the flow. They vary from a dark olive to light olive, again in sizes 16 and 18. The emerger stage has different colors for the exoskeleton and the emerging dun. I like darker olives or browns in the rear for the exoskeleton and lighter olives in the front for the emerging adult.
Pale Morning Duns also are size 16 to 18. The dun’s body color is a creamy yellow. The wing is usually light gray. The nymph ranges from light olive to dirty yellow in sizes 16 and 18. Body shapes vary from round to flat, according to habitat. The emerger stage is cream or creamy yellow throughout both the exoskeleton and the emerging dun. The predominant color of the PMD in the valley is a creamy yellow.
Pink Albert (Pinkies), are size 16 and 18. The dun’s body colors are different shades of creamy pink, with tans mixed in. The wing is usually tan or brownish gray. This is another flat-bodied clinger nymph, and its color ranges from light brown to light olive. The emerger stage is light cream or tan in the exoskeleton and lighter creamy pink in the front for the emerging dun. The predominant dun Pinkie color in the valley is a creamy pink body with a tan wing.
Three other species of mayfly also hatch on the valley rivers — the Callibaetis, Pale Evening Dun, and Brown Drake — but you don’t actually need separate patterns to cover these hatches successfully. The Callibaetis are found in places in the stream with muddy or silty bottoms and look similar to Blue-Winged Olives. The Callibaetis dun will have a longer tail, but their colorations are similar, and we use the same flies for the Callibaetis that we use for the BWO. Likewise, the Pale Evening Dun is similar to the Pale Morning Dun, but its wing is a darker gray. The same imitations that we use for the Pale Morning Dun work well for the Pale Evening Dun. The Brown Drake is identical to the March Brown in color, just larger in body size — a size 10 or 12. Larger March Brown imitations work well for the Brown Drake hatches.
On undammed, freestone streams, hatches tend to follow one another in a certain order throughout the year, but the lower Sacramento, Yuba, and Feather Rivers are tailwater fisheries, downstream from a dam, where the bottom releases keep the water cool in the summer and at a relatively constant temperature in the winter, and different hatches can occur at the same time in different parts of these rivers. You will be fishing a March Brown hatch in one riffle, and in the next one you may encounter a Pink Albert hatch. Also, the fish might be concentrating on eating the emerger in one place and the dun in another. Carrying a wide variety of mayfly imitations in all the different life cycle stages is a must to be a productive fly fisher on these rivers.
Fly Patterns for Valley Mayflies
Recognizing what’s hatching is pretty straightforward, but there are a zillion mayfly patterns out there, and any fly shop you enter has plenty of options to choose from. It’s said that the best fly to fish is the one you’ll fish with confidence. I’ve listed my top flies for these hatches, but I also reached out to some of my compatriot guides, fly tyers, and writers to get their picks for the flies that they feel confident fishing for certain mayfly hatches and certain stages of the hatch in the valley fisheries — Zack Thurman, Hogan Brown, Brian Clemens, Brian O’Keefe, and the master himself, Mike Mercer.
My top flies for the March Brown hatch are the Parachute March Brown in sizes 14 to 16 for the dun. For the emerger, I love the Quigley Marabou Cripple March Brown, size 14, because it’s easy to see. For nymphs, I like Hogan’s Military May, the Pheasant Tail Nymph, and Lance’s X-May Brown, all in sizes 14 to 16.
My top BWO flies are the Purple Haze Parachute, Mercer’s Missing Link in olive, and the Parachute Adams for the dun, all in size 16. For the emerger, it’s the Quigley Marabou Cripple in olive, size 16. The nymphs are Hogan’s S&M in olive, the Pheasant Tail Nymph, and Lance’s X-May in olive, sizes 16 to 18.
For PMD duns, I like a Hi-Vis PMD Parachute size 16 to 18. For emergers, I like all of the Bob Quigley’s standard Emerger PMDs in size 16. For nymphs, I choose Lance’s X-May PMD, Mercer’s Micro May PMD, and Hogan’s Military May PMD in sizes 16 to 18. For Pink Albert duns, I like Tom Page’s Pinkie (which you should be able to find at his Grass Valley fly shop) and Mercer’s Missing Link in cream, size 16 to 18. For the emerger, I like the Last Chance Cripple Pinkie in size 16. For nymphs, I use Lance’s X-May Brown and Hogan’s S&M Brown in sizes 16 to 18.
The responses I got from my friends focused on a few favorite patterns. For a March Brown nymph, Zack Thurman likes Thurman’s Pseudo May in brown, size 16, and Mercer’s Foam Parachute Adams in size 16 as a general mayfly attractor. Hogan Brown listed his S&M Nymph in either olive or brown in sizes 16 to 18, and for a dry fly, he likes a Quigley Sparkle Dun, color and size to match the hatch. Brian Clemens’s go-to flies are Lance’s X-May in olive and Hogan’s S&M PMD in size 16, with the Parachute Adams in a size to match the hatch as a general mayfly attractor. Brian O’Keefe likes the Two-Bit Hooker nymph in brown and the standard Pheasant Tail Nymph in size 16, with a Hi-Viz Parachute Adams as a general mayfly attractor, sized to match the hatch, and a CDC Comparadun for BWOs and PMDs in size 16. Mike Mercer mentioned only one fly, his Mercer’s Missing Link dry, color and size to match the hatch.
Fishing Mayflies on Valley Rivers
Part of fishing a fly with confidence is how much faith you have in your presentation. For fishing dry flies and emerger patterns, my friends and I agree that a downstream presentation is the ticket. That way, the fish are likely to see your fly first, rather than your leader and line, which might spook them. Strip off 40 to 50 feet of line, but make just a short cast slightly across and downstream. Then feed the slack line out by flipping your rod tip up and down, tossing small amounts of line out as if you were mending it downstream. Your mends should match the speed of the fly on the water. The faster you flip, the faster you release the line. Just try not to move the fly. The only problem with this presentation is that you may tend to pull the fly away from the fish when it takes the fly. I tell myself, “Feel the weight and the fish then set the hook.” Wait until the fish actually bends your rod and smoothly lift the rod for the hook set. Mike Mercer calls the downstream presentation “feeding the fish.”
Long leaders also help keep the line away from the fish, but long leaders can also be difficult for a fly fisher to turn over during the cast. The downstream presentation does away with this problem — it’s all about feeding out the line and leader to achieve a drag-free drift. When presenting the fly downstream, I like leaders 12 to 15 feet long, which helps keep the fly line out of sight. My leaders are made of 3 feet of 40-pound monofilament butt material with a Perfection Loop attached to my floating fly line, followed by a factory-made 9-foot monofilament leader tapered to 4X. I cut the loop off the top of the factory leader and marry the leader to the butt section using a Blood Knot. At the tippet end of the tapered leader, I add 3 feet of either 4X or 5X monofilament tippet material, again using a Blood Knot, with the size of the tippet material dependent on the size of fly I am fishing.
A lot of fly fishers, including some of my friends, fish nymphs under an indicator, but I’m old school. When I started fishing nymphs, indicator nymphing was just beginning to make its appearance in the fly-fishing community, and straight-line nymphing, also know as “high sticking,” was the preferred tactic. Straight-line nymphing is simple. You cast your nymphs slightly upstream and across, and as they start to drift in the current, you lift the rod tip to keep the line and leader off the water as much as possible to minimize slack and maintain a tight connection to the flies. When the flies go by, you swing the rod tip to track them and also begin dropping the tip to extend the drift while still maintaining a taut connection, until the line is straight downstream below you and the current swings the flies toward the surface. Compared with indicator nymphing, I have found that when using straight-line nymphing, I catch more fish because with the line taut I am always in touch with the fly, which enables me to feel strikes and to hook fish quickly.
Rigging a straight-line nymphing setup also is simple. I like a long leader for straight-lining, but not as long as my dry-fly leader — it’s around 11 feet long. I start with a 9-foot 4X factory-made tapered leader. I then add a 2-foot piece of 4X tippet material to the terminal end with a Blood Knot. When you tie that knot, two tags remain. One will be facing down, toward the terminal end of the leader, and the other will be facing up, toward the fly line. Cut off the tag that is facing up, and on the bottom tag, tie on a beadhead nymph. Then, at the terminal end of the tippet, tie on another beadhead nymph. I also place split shot on my tapered leader right above the Blood Knot. This keeps the flies drifting right along the bottom (and maintains line tension), but still allows the nymphs to rise at the end of the drift, which imitates them swimming or drifting to the surface to hatch.
You can also add a sighter to your leader. This is just something that makes it easier to see the leader while you are fishing. It can be as simple as a bit of colored backing tied onto the leader or colored monofilament added to the butt of the leader, or it can be as elaborate as the coiled monofilament sighters developed for Euro nymphing. When fish stop the fly, the leader hesitates slightly, and the sighter helps you see that happen.
Frankly, though, I just use a bobber stopper as a sighter. A bobber stopper is designed to keep a strike indicator in place, but there is no reason why the bobber stopper can’t likewise serve as an indicator. One of the nice aspects of bobber stoppers is that you can slide them up and down your leader without too much difficulty, allowing you to adjust their placement when fishing water of varying depths. They are available in vibrant colors — red, chartreuse, and blue.
Valley Tailwater Fishing
California’s Central Valley Rivers offer anglers the opportunity to target fish feeding on mayfly hatches throughout the year, with the added bonus that these tailwaters often support multiple hatches at the same time. When streams at higher elevations aren’t accessible yet or are too low and warm to fish, it’s worth focusing on valley mayflies for angling success.
Confidence Flies
Here are recipes for some of the flies that guides fish with confidence for the mayfly hatches on Central Valley tailwaters.
Hi-Vis Parachute Adams
Hook: TMC 100, size 10 to 20
Thread: Gray 6/0 Danville Flymaster
Wing: Mixture of fluorescent yellow and pink
Tail: Grizzly and brown hackle fibers, mixed
Hackle: Grizzly and brown hackle, mixed
Body: Gray dry-fly dubbing
Hogan’s S&M Nymph
Hook: TMC 3769, size 16 to 18
Bead: Copper, size to match hook
Thread: Olive dun 8/0 UNI Thread
Tail: Olive pheasant tail fibers
Rib: Small black wire
Body: Olive dun 8/0 UNI Thread
Wing case: Black goose biot
Thorax: Medium olive Wapsi Antron Sparkle Dub
Legs: Olive Midge Krystal Flash
Mercer’s Missing Link
Hook: TMC 100, size 14 to 18
Thread: Camel 8/0 UNI Thread
Body: Camel 8/0 UNI Thread
Rib: Pearl Flashabou
Body coating: Softex
Wing splitter dubbing ball: Brown UV Ice Dub
Down wing: Light dun Z-Lon
Up wing: Natural cow elk hair
Hackle: Medium dun rooster neck or saddle
Thurman’s Pseudo May Brown
Hook: TMC 2457, size 16 to 18
Bead: Copper, size to match hook
Thread: Brown 6/0 Danville Flymaster
Tail: Natural pheasant tail fibers
Rib: Small copper wire
Body: Same as thread
Wing case: Black scud back
Thorax: Brown Sparkle Pseudo Hackle
Legs: Peacock Midge Krystal Flash
— Lance Gray
The Adams and the Parachute Fly
Knowing the history of fly patterns and tying techniques can add to your enjoyment of our sport. There are people who claim that when it comes right down to it, all you need to carry to catch fish is a Parachute Adams in a variety of sizes. The combination of the Adams dry fly, a classic pattern, with the parachute style of tying marks a notable milestone in the history of the sport. Here’s a bit of background on both the Adams and the parachute style.
In 1922, an attorney named Charles Adams was fishing with his son on the upper Boardman River in upstate Michigan during a mayfly hatch. Frustratingly, they didn’t have a fly that would match the hatch. They turned to a friend, a professional guide and fly tyer named Leonard Halladay, to create a fly that would improve their success. Halladay developed a dry fly that when fished by the Adamses was very productive. Halladay went on to sell the fly to locals and named it after his friends — the Adams.
The original fly recipe had a tail of golden pheasant tippets, a body of gray muskrat dubbing, grizzly hen hackle tips for wings, and rooster hackle of mixed brown and natural grizzly. In the next decades, the Adams was refined by many tyers, mostly in the Catskill region in New York. The tail of golden pheasant tippets was replaced by mixed brown and grizzly hackle fibers, and the wings were tied with grizzly rooster hackle tips, rather than the webby grizzly hen hackle tips.
As for the parachute style of fly tying, in 1931, a Scottish fly tyer named Helen Todd, after getting inspiration from an article from an American fly-fishing magazine, thought that wrapping the hackle horizontally up the wing, rather than around the shank of the hook, would make a better imitation of a mayfly and let the fly ride perfectly on the water’s surface. Her employer was Alexander Martin, who owned a fly-fishing company in Glasgow, Alex Martin Ltd. Martin designed a hook that had a metal post positioned on top of the shank to help secure the horizontal hackle. During the same period in the United States, a fly tyer named William Brush designed a similar hook for the same purpose. Fly tyers learned over time, of course, that they did not need a special hook to create a parachute pattern.
Put those two innovations together, and we now have multiple Adams patterns, including the Hi-Vis Parachute Adams of today — a great mayfly adult imitation and is one of the flies I often fish.
— Lance Gray
The Mayfly Life Cycle
For fly fishers, the mayfly’s life cycle has four important elements:
- The underwater nymphal stage, which represents most of the mayfly’s lifespan. The nymph grows and, when size and water conditions such as temperature are right, it moves toward the water’s surface, where . . .
- The dun stage of the adult mayfly emerges from the nymphal exoskeleton. Emergence can be slow or quick, and the insect is particularly vulnerable to trout at this stage. It also is vulnerable while . . .
- The dun sits on the water’s surface as its wings become ready for flight. It then flies from the water and heads to streamside vegetation, where . . .
- It molts to become a sexually mature adult. This is known as the spinner stage. The spinner will join other swarming spinners in the air to mate and, if female, deposit eggs in the water. Spinners then drop to the surface and expire, again becoming available to the fish, and the life cycle begins again.
