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Tuesday, November 16, 2010

Baetis Complex - Part IV - Presentation of BWO Emergers and Dries & Proven BWO Patterns

When most of us think about fishing the Baetis hatch or for most of us, referred to as the BWO hatch, we usually think about the small mayfly duns rafting down the river. This is the portion of the life cycle that we are probably most enamored by. We must not forget the emergent and crippled BWO's that are often caught in or under the surface film or the spinners that often go unnoticed.

I'll never forget the first time I encountered a blanket BWO hatch which was on the Henry's Fork in Idaho. I was fishing in late September or maybe it was early October. I was fishing the box canyon with Pete Stahl. The weather had turned cold and we were fishing in a cold drizzle and intermittent snow. The run we were fishing had rafts of Baetis duns. I remember there were probably 100's of duns per square foot. They were size 20's and maybe even 22's. I looked in my box and the best imitation I had was some BWO parachutes in a size 18 and I gave it a go. My size 18 looked like an air craft carrier compared to the naturals. At least it let me tell my imitation from the naturals. Luck was with me that day, I guess there were a number of trout that were looking for a bigger meal. I also remember my hands being so frozen that I could hardly get the hook out of the fishes mouth to release it. It was what I remember as a glorious but miserable day. A time that I remember vividly to this day.

Well, on to the Fishing Discussion.

Fishing a Nymph Just Under the Surface

When the duns first appear, you may want to continue fishing a nymph rigg, with a long leader and present the fly with upstream casts, just as you would a dry fly to a rising fish. Let the small imitations sink a few inches below the surface film. It may be necessary to treat all but the last few inches of your fly line with floatant. This will keep the fly up in the water column and help you to detect strikes. You may want to add a tiny yarn indicator into the leader five or six feet up from the fly. Set the hook to any movement of the indicator or to any visible rise anywhere near it.

Dry and Dropper

You can also fish the Baetis complex hatch with a dry dropper setup. You can tie one or two un-weighted nymph droppers about 2 to 3 feet behind the dry. The dropper can be tied to the hook bend of a dry fly chosen to imitate the dun. You might even want to try a cripple as the fly in the surface film if the currents are smooth enough to see it.

Presenting Drys and Emergers

When presenting dry flies and emergers to a Baetis Complex hatch on smooth currents, you will be required to fish with delicate precision. The trout are almost never more careful in their feeding lanes, nor will they move far out of range to take a natural or its imitation. The fish are typically feeding in the smoothest of currents so stealth is a must.

Before making a cast, take up a position as near to the rising trout as you can without alerting them to your presence. Look for a position that will put as many conflicting currents behind you rather than leaving them between you and the trout. This is the water your line will land on. When encountering a pod of rising fish target a single fish, time its rhythms, and cast to it carefully and deliberately. This is the best tactic as opposed to casting at random to the pod of lifting and subsiding noses.

There are two prime positions to present your imitations. Try to position yourself either directly across stream from the trout, where you will use a reach cast. Or, place yourself upstream and slightly off to the side of the trout, in position for a downstream wiggle cast. Both of these casts allow you to show your fly to the trout instead of your line and leader. Be as accurate and gentle with each cast as you can. It may take a long time and many casts before all the stars align and the trout takes your fly in rhythm, in its feeding lane.

If you find it necessary to make an upstream presentation and the fish are feeding on the surface, place the fly just a foot or two upstream from the position of the fish. That way a very little amount of the leader and no line are allowed to fly through the air and over the head of the fish. It doesn’t take much to get a feeding fish to head for cover.

Baetis complex nymphs are so small and hatch so often on smooth currents, they are susceptible to getting stuck in the film, Hogan Brown has created a pattern BWO SIM which is for (stuck in the middle). The dun often finds itself half in and half out of the nymphal shuck. They are helpless in this position, and trout often feed selectively on them.

The emerger imitations should float flush in the film and should represent both the emerging dun, or at least its wings, and the trailing shuck. Many anglers and guides often fish the emergers during the Baetis complex hatches.

Rigging up

When fishing the Baetis complex hatch you should use your finest presentation outfit. Many anglers use a 3 or 4 weight set-up. This hatch requires short and accurate casts with the most delicate presentations.

Proven Baetis Emergers and Dry Fly Patterns

Emerger Imitations

Baetis Emerger

Hook: Standard dry fly, 1x fine, size 16-24
Thread: Olive 8/0
Tails: Blue Dun hackle fibers, split
Abdomen: Pale Olive to olive-brown fur or synthetic dubbing
Wings: Ball of gray synthetic dubbing, as knot
Thorax: Slightly darker dubbing than abdomen
Legs: Blue dun hackle fibers

Pattern Notes: When fishing this fly, you can either treat just the ball or knot with floatant, and fish the fly suspended from the surface film or you can also dress the entire fly and fish it flush in the film.

Krystal Flash Baetis Emerger (Originator: Rick Hafele)

Hook: Tiemco 2457, 1x short, size 16-22
Thread: Olive 8/0
Tail: Olive or tan CDC fibers as long as the hook shank
Body: 4 to 6 strands of tan, olive, or mix of olive and tan or olive and brown Krystal Flash tied in at the hook bend, twisted into a fine rope and wrapped up the hook shank.
Wings: Gray CDC fibers
Thorax: tan to dark brown dubbing with guard hairs picked out.

This pattern is similar to the Krystal Flash nymph, but with the addition of CDC it floats perfectly in the surface film and represents the key elements of the emerger stuck there with the trailing shuck and unfolding wings. You can vary the colors to match most any BWO hatch.

Olive Sparkle Dun (Source: Juracek and Mathews)

Hook: Standard dry fly, 1x fine, size 16-24
Thread: Gray 8/0
Wing: Natural deer hair, tied Compara-dun style
Tail: Olive brown Z-lon
Body: Gray-olive fur or synthetic dubbing

This pattern is a standard emerger pattern and represents the emerging process as it nears completion, the dun is fully formed, but the nymphal shuck is still attached. This fly is actually representing the emerger and the dun with a single pattern.

Barrs Emerger (Originator - John Barr)

Hook: TMC 2487 or 2488 #16-24
Thread: 8/0 Iron Dun
Tail: Brown Spade Hackle Fibers
Abdomen: Olive Brown SuperFine Dubbing Wingcase: Dark Dun Spade Hackle Fibers Thorax: Grey Muskrat or Beaver Dubbing Legs: Leftover tips of wingcase fibers

The Barr Emerger is "Go To" pattern. The idea behind this pattern, according to John Barr, was to imitate the adult insect creeping out of the nymphal shuck. This pattern is meant to be fished below the surface, anywhere from streambottom to an inch under the surface. Fish the Barr Emerger down along the bottom with a split-shot on the leader and an indicator above, or as a point fly in the Hopper/Copper/Dropper system.

RS2 Emerger

Hook: Tiemco 2487 #18,20
Thread: Gray, Olive, Olive Brown 8/0
Body: Muskrat under fur
Tail: Microfibetts gray
Wing: White Foam

Quigley's Olive Marabou Cripple (Originator - Bob Quigley)

Hook: Daiichi 1180 #12-#20
Thread:Light olive 6/0 or 8/0
Tail: Olive marabou.
Rib: Gold wire
Abdomen: Olive marabou
Wing:deer hair.
Hackle: Tinted yellow/olive grizzly or light blue dun grizzly
Thorax: Light olive or yellow spun hair

CDC Baetis Baetis

HOOK: TMC 100, sizes 16-20
TAIL:Betts' Tailing Fibers
BODY: Olive Dazl-Tron
WING: CDC, natural dun color

Parachute Baetis

HOOK: 900BL, sizes 16-20
WING: Mallard flank, tied parachute style
TAIL: Two blue dun Micro Fibbets, split
BODY: Olive Haretron or Superfine
HACKLE: Natural or olive-dyed grizzly

DIVING BAETIS SPINNER: Pattern from Planet Trout

HOOK: TMC 100, #16-#22 or Daiichi 1100, #16-#22

THREAD: Gordon Griffith 14/0 sheer, olive or dark Brown

TAILS: Dun Micro Fibetts

EGG SAC: Olive-Yellow or Rusty Brown dubbing

ABDOMEN: Olive or Rusty Brown Goose or Turkey Biot, to match the naturals color

THORAX: Pearl Bead

WING: Z-wing or Tan or Gray raffia ( Swiss Straw)

HACKLE: Starling

This particular rendition is from Allen McGee …it may also be viewed here at WESTFLY- where the egg sac seems to be missing…this pattern is best presented on a tight line and dead drifted…the spinners are washed away after completing their mission and won’t be returning to the surface, unless pushed there by the current…

You can pick up Dave Hughes book, "Western Mayfly Hatches" at Amazon books by going to the following link. It is where most of this information came from.

Thursday, November 11, 2010

Baetis Complex - Part III - Presentation for BWO Nymphs and Proven BWO Nymph Patterns

I personally have the most experience fishing with baetis nymphs on the Lower Sacramento River below Redding here in Northern California. Some of the best baetis nymph patterns that I have come across have been developed and thoroughly tested there. Patterns developed by Mike Mercer, Hogan Brown, Ken Morrish, Brian Silvey, to name a few, have developed "go to" patterns where ever baetis complex bugs are found. There are times on the Lower Sacramento where the small bugs dominate the preference of the trout and it's becomes "go small or go home".

As a note, fishing the baetis complex on the Lower Sacramento is almost entirely a deep, dead drifting affair with long fine leaders.

Baetis Complex Nymph Presentation

On most streams and rivers and when targeting the Baetis complex, the pre-hatch restlessness of the swimming nymphs make then available for some time before the duns appear on the surface. Baetis nymph patterns are most effective as (1) searching dressings fished deep along the bottom or (2) fished high in the water column over feeding trout just before the hatch. There are some instances where trout will continue porpoising and tailing to nymphs throughout an entire hatch and ignore the duns completely.

Searching Dressings Fished Deep

During the hours when no BWO hatch is happening, small nymphs can be fished with a free drift on or very near the bottom using the split shot and indicator method. I usually rigg with a 9ft 3x leader to the split shot and then tie two to three nymphs tied hook bend to hook bend. I match the terminal tippet to the small size of the baetis imitations and go down to 5x fluorocarbon. I've come to recommend the thing-a-ma-bobber as the indicator of preference.

Unweighted Nymphs Fished Shallow

In the hour or so before the hatch, the same flies can be fished with some success using the traditional wet fly swing, just inches deep. Mend the line to slow them to the speed the restless naturals might move in their attempts to move to the surface and then back down to try again.

When the duns appears, it's a not a bad idea, to continue fishing a nymph, but high in the water column. Rigg with a long leader and present the fly with upstream casts, just as you would a dry fly to a rising fish. Let the small imitations sink a few inches below the surface film. It may be necessary to treat all but the last few inches of your fly line with floatant. This will keep the fly up in the water column and help you to detect strikes. You may want to add a tiny yarn indicator into the leader five or six feet up from the fly. Set the hook to any movement of the indicator or to any visible rise anywhere near it.

Dry Dropper

You can also fish the Baetis complex hatch with a dry dropper setup. You can tie an un-weighted nymph dropper about 2 to 3 feet behind the dry. The dropper can be tied to the hook bend of the fly chosen to imitate the dun. You might even want to try a cripple as the fly in the surface film. You are effectively giving the trout two options.

Your Outfit

It is stated that when fishing the Baetis complex hatch you should use your finest presentation outfit. Many anglers use a 3 or 4 weight set-up. Here on the Lower Yuba when I'm wading I'll typically stick with a 5 weight. We typically come across the BWO's in the runs which is more nervous water, or in back eddies. There are some flats that have more of a spring creek feel to them and I'm sure my presentations could benefit from going with a smaller rod and line. Whichever outfit you use, this hatch requires short and accurate casts with the most delicate presentations.

I'm most often fishing the Northern California rivers from my drift boat and am usually gunned with a Sage XP or Z-Axis 6 weight. We're usually fishing deep under indicator and the 6 weight handles this rigg really well. It also helps when you hook up a large Lower Sacramento or Lower Yuba rainbow.

Baetis Complex Nymph Imitations

The Baetis Complex nymphs range in size from a size 14 down to size 24. The most common sizes are 16 to 20. Colors of the naturals vary from pale olive to dark olive-gray and dark olive-brown to brown. Their imitations should be tied on 1x short to 1x long hooks and are usually tied un-weighted.

It must be said that there is no better way than to to do stream sampling of your own home waters and match (1) size (2) shape (3) color of the naturals. There are just too many sizes and variations to cover all the baetis complex nymphs. As with most imitations, the size and the shape are of the most importance.

Many experienced fishermen and guides have found that trout routinely feed on these small nymphs even when there is no hatch activity. Many times a small Baetis nymph will out perform a larger imitation in non-selective situations, especially in waters where good numbers of the naturals are found. When the hatch does occur, fish will feed selectively on the tiny nymphs during the early stages of the hatch.

Proven Baetis Patterns with Recipes

For the fly tyers out there, here are some recommended patterns that also have tying recipes. There are many commercially tied patterns available out there at fly shops all over the west, but in many instances the recipes are proprietary and not readily available. This list provides patterns that you can tie and will cover the Baetis complex hatches wherever you find them. Tie them in the right sizes, and colors to match the baetis nymphs you find on your streams and rivers and you'll be good to go.

I've provided a list of commercially available "Go To" flies in a previous blog article

Pheasant Tail (Originator: Frank Sawyer)

Everyone should carry Pheasant Tail nymphs and Flashback Pheasant Tail nymphs in their boxes. It is one of the best all around nymph pattern you can find.

Hook: Standard nymph, 1x long, size 14-24
Weight: Scant turns of undersized lead wire, or omit
Thread: Brown 8/0
Tails: Pheasant tail fibers
Rib: Fine copper Wire, counter wound over abdomen
Abdomen: Pheasant center tail fibers, as herl
Wingcase: Pheasant tail fibers
Thorax: Pheasant tail fibers as herl
Legs: Tops of thorax fibers

Pheasant Tail Flashback

Though the Pheasant Tail as per the pattern above is more imitative of the natural nymph, many tiers consider the Pheasant Tail Flashback the more effective pattern. To tie this pattern as a Flashback, use Pearl Flashabou in place of the pheasant-tail fibers for the wingcase.

Baetis Nymph
(Originator Unknown) No photo available at this time. Refer to the book "Western Mayfly Hatches" listed at the end of this article. This impressed me as a good one to use as a standard pattern tied to match the baetis nymphs in your stream.

Hook: Standard nymph, 1x long, size 12-24
Weight: Scant turns of undersized lead wire, or omit
Thread: Olive 8/0
Tails: Olive-dyed mallard flank or partridge fibers
Abdomen: Light olive to dark olive-brown fur dubbing
Wingcase: Mottled turkey tail or dark goose primary feather section
Thorax: Slightly darker fur than abdomen
Legs: Olive-dyed mallard flank or partridge fibers or thorax fur picked out

Pattern Notes; This is a good standard nymph pattern for members of the Baetis complex for a more accurate match. This pattern is well suited to collecting of a natural and then matching the color. Remember that colors of the baetis Complex can change from stream to stream and even different portions of the same stream. It is most likely that trout will accept this pattern in the medium range of colors, most of the time. Size and form is most important.

Krystal Flash Baetis Nymph (Originator Rick Hafele)

Hook: Tiemco 2457, 1x short, size 16-20
Weight: None
Thread: Olive 8/0
Tails: 3 to 6 light gray hackle fibers
Abdomen: 4 to 6 strands of peacock Krystal Flash, or a color to match your own naturals, tied in at the hook bend, twisted into a fine rope, and wrapped up the hook shank
Wingcase: Mottled turkey tail or strands of dark brown to black Krystal Flash
Thorax: Tan to dark brown fur dubbing with guard hairs picked out

Pattern Notes: This small nymph sinks well because of the Krystal Flash body, yet the loosely dubbed thorax retains some life like action. It can be fished deep or just under the surface. It presents a realistic impression of the natural when tied in the appropriate size and color. It is durable and easy to tie.

Hogans S&M Nymph (Originator Hogan Brown)

Hook: TMC 3769 #16-18
Thread: Dark Brown 8/0
Weight: Copper Bead
Ribbing: Wapsi Olive Ultra Wire, SM
Abdomen: Olive Thread 8/0
Tail: Pheasant Tail Fibers
Wingcase: Dark Brown Goose Biot
Thorax: Dark Olive Antron
Legs: Olive Krystal Flash

Notes: I first started using the S&M Nymph when fishing the Lower Sacramento River and it has been a proven producer. When the Lower Sac goes into the small bug bite mode I usually have an S&M nymph or a Military May nymph rigged up. From what I have researched the S&M nymph is weighted by use of a Copper bead head but has additional sinking capabilities through the use of a thread body, streamline shape, and Ultra wire for the distinct segmentation. Hogan uses a Goose Biot for the wingcase which provides a distinct color contrast to the thorax which is typical with natural Baetis nymphs having a darker hue on the top of the thorax. Krystal Flash is used for the legs which provides attraction and movement to the fly yet does not detract from it's sinkability. I've often used it as a dropper on the Lower Sac and Lower Yuba when I need to get the nymph down quickly.

Other Proven Hogan Brown Nymphs: I don't have recipes for some of Hogans other nymph patterns such as Hogans Military May - BWO and Hogans Better Baetis. You can get them anywhere that sells Iydlwilde Flies.

Pale Baetis Nymph (Originator Jeff Morgan) Pattern from Westfly

Hook: Dai Riki 310, size 20-22
Thread: 8/0 rusty dun
Tail: Three short widgeon flank feathers
Abdomen: Tying thread, perhaps counter-ribbed with iron gray 8/0 thread
Thorax: One or two wraps of pale olive dubbing
Wingcase: Mottled oak Thinskin
Legs: Pale olive Antron fibers, sparse

How to Fish - In rivers, the fly can be presented near the surface, but it is usually most productive when fished near the bottom on a dead drift with the indicator or tight line presentations. To achieve the right depth, you may need to put weight on the leader or use the fly on a dropper with a heavier fly on the point. While the fly works well as a searching nymph, it can also be productive during a hatch (more trout than you might suspect are taking nymphs off the bottom rather than duns off the top).

Hot Spot Pheasant Tail (Originator Unknown) pattern from Westfly

Hook: Mustad 9671, sizes 8-20
Thread: Brown
Tail: Four pheasant tail fibers
Rib: Fine copper wire
Body: Pheasant tail fibers wrapped on hook
Thorax: Orange or chartreuse Haretron or sparkle dubbing
Wingcase: Pheasant tail fibers pulled over the thorax

Uses - The bright thorax may help fish focus on this variation of the traditional Pheasant Tail Nymph. "Hot spots" such as this bright thorax may not be as unnatural as they might appear.

Variations - Can be tied with or without a beadhead. Vary the size to match different insect species.

You can pick up Dave Hughes book, "Western Mayfly Hatches" at Amazon books by going to the following link. It is where most of this information came from.

Sunday, November 7, 2010

Baetis Complex - Part II - BWO Behavior and Habitat

The Blue Wing Olives have been coming off regularly on the Truckee River and you need to check out Matt Coles blog and he'll give you some good insight as to fishing the BWO hatch. You can check out his weblog at

With that said, here's Baetis Complex, Part II, Behavior and Habitat

The Baetis Complex or Blue Wing Olive mayflies are said to be the most important to the fly fisherman. Knowing the behavior and habitat of these mayflies can be most beneficial when you encounter them on your favorite stream. We often see BWO's in the eddies and soft water as we float the Lower Yuba and the Lower Sacramento River.

, BWO Nymphs

Nymphs for the Baetis complex are found in most flowing water habitats. In freestone streams they live in quite pools, slow eddies and even white water rapids, but are most common in shallow, sun-struck riffles where algal growth is most abundant.

Though the BWO nymphs are found in fishable numbers in freestone waters, these nymphs often reach their greatest abundance in gentle tailwater and spring creek currents. Our local Lower Yuba River has these elements and a good population of baetis nymphs, although their population is subject to seasonal scouring which can affect their habitat.

Behavior of the nymphs of the Baetis complex is predicted by their nature as being a member of the Swimmers group. Quick pulsing movements of the abdomen combined with flips of the tail propel them in short bursts of three to five inches. When they stop swimming they immediately cling to the substrate facing upstream. Their active behavior causes them to be a common component of stream drift. This makes them available to deep nymphing methods almost 365 days a year.

The Baetis complex nymphs feed on "diatoms" or small "detrial" material they scrape from the surface of submerged vegetation or rocks. The nymphs go through as many as 27 instars. The mature nymphs, those ready for emergence, are easy to recognize by their dark well developed wingpads. By turning rocks over and inspecting the nymphs you fins, you can predict with fair accuracy the likehood of a coming hatch. If you see the baetis nymphs with the darker colored wingpads, a hatch is probably coming up.

Baetis, BWO Emergers and Duns

To emerge a baetis nymph releases it hold on the bottom and floats or swims to the surface, drifting downstream with the currents as it rises to the surface. After breaking the surface film, the dun quickly bursts out of the nymphal cuticle. The dun normally leaves the surface immediately but on cold days they may float as long as fifty feet before getting airborne.

The surface film can be a substantial barrier for these tiny bugs, especially on smooth currents. Wind and broken water breaks up the barrier and makes their emergence much easier. When BWOs are hatching in calm waters many fail to make it through the surface film. The result is a high percentage of cripples, stuck in the surface film. When this happens at least some of the trout focus on feeding on them and will ignore the duns on the surface. The fish may refuse your best dun imitations and your best presentations. This is time when you need to fish emerger imitations.

As with most match the hatch fishing, observation is the most important tool in your bad of tricks. If you ever carry a pair of binoculars, this is where they really help. Watch the BWO duns as they float on down the current and when a trout rises and breaks the surface, check to see if the duns are still floating on downstream. If they are, theres a very good chance they are keying on the emergers and cripples.

Baetis, BWO Spinners

Seven to eight hours after emergence the duns molt to spinners. Mating flights usually occur mid-day, from late morning to early afternoon. After mating, females of many Baetis complex land on protruding rock and sticks and crawl underwater and lay their eggs. After laying their eggs they either crawl back up to air or they let go and are swept downstream and are often eating by awaiting trout. This submerged egg-depositing behavior is unique, among mayflies, to members of some of the Baetis complex. Again some and not all.

There are other species in the complex that lay their eggs on the open water's surface. The females soon die after all the eggs are laid.The trout will sometimes feed on the tiny transparent, empty hulls. This is a time when a spinner pattern may solve this problem. When fish are taking spinners it is often easy to overlook and not an easy portion of the hatch to solve.

You can pick up Dave Hughes book, "Western Mayfly Hatches" at Amazon books by going to the following link. It is where most of this information came from.

Tuesday, November 2, 2010

Baetis Complex - Part I - Blue Wing Olive Mayflies

Here in Northern California and as we head into the fall and winter it is time to get ready for the main portion of our blue wing olive season. This is an over view of the Baetis Complex, or in common terms the Blue Wing Olive complex, that we will encounter here in Northern California and in the west.

Family Baetidae

The Baetis group of mayflies represents the most complex family of mayflies. The Baetis are of the Swimmers group of mayflies. There are sixteen genera and more than 60 species of Baetidae that occur in the west. This is often referred to as the Baetis complex. It is considered by many, to be the most important of all western hatches. The BWO hatches are so diverse and can be so prolific that they cause more selective feeding, more often than any other insect group. This is why getting to know and understand the Baetis complex is so important.

The most important thing to remember is that fly patterns for one species of Baetis will be just as effective for the others. You will need to change the size and the color as you encounter the different species on the river that you find yourself.

Emergence and Distribution

The Baetis complex is a large and widely distributed group, found in great numbers in all of the western states. With proper adjustments in size and color of your imitations you'll be able to match any Baetis hatch. For the fisherman, knowing the identification to the Baetis complex level, is as much as you practically need to know. You will need to focus your attention on finding an appropriate imitation and then fishing it with the most productive presentation. It is more important to get to the business of fishing and not worry about which species it may be within the complex. In simpler terms, collect a sample, match size and color and get on to fishing.

The Baetis complex hatches can occur at anytime of the year, depending on the species, the geographic area and the current weather conditions. Most adults emerge in the winter and spring. The exact timing of the hatches depend upon the species and the water temperatures in the waters that they live. Because the Baetis complex is so large, you must study the hatches on your own home waters in order to predict the hatches with any accuracy. Here in Northern California, the BWO hatch is primarily a later fall, winter and early spring hatch. With that said, because of their abundance and diversity, it makes the Baetis complex, or Blue Wing Olive mayflies, important at one time or another, on almost every western river and stream.

The daily emergence times of the various species change with the season but are typically in the warmer part of the day. In early spring the hatch will be from early to late afternoon, when the air and the water are the warmest. Mid summer hatches might move towards morning, or more commonly evening, when the conditions are cooler. In the fall, the hatches move back towards the warmest hours, again occurring between late morning and early afternoon.

It is well documented that the Baetis complex hatches occur on cool, overcast and even wet and snowy days. On warm and sunny days, the hatch is often truncated into a brief period. On cloudy days you'll get a trickling hatch that can go on for two to four hours with trout up in the water column and feeding all that time. On a bright day the hatch will often be heavy, but last only a half an hour to an hour. On these days the hatch can be over before you realize it is going on.

Because of the small size of the Baetis complex, the hatches of these mayflies are often overlooked by fisherman. The fish rarely make this mistake. For some reason when you have hatches of Blue Wing Olives happening at the same time as that of a larger insect, the trout often ignore the larger meal and become selective to the Baetis complex. A lot of anglers make the mistake of fishing imitations of the larger bug and the fish are focusing on the smaller Baetis.

Some fishermen consider Blue Wing Olive duns to be the most important stage of this complex, but studies have shown that the nymphs are a consistent and important food item nearly every week of the year. Trout feed heavily on nymphs during the pre-hatch activity and can also become selective to spinners when they fall in abundance. Because of their small size, emerging adults are often trapped in the surface film during the transition from nymphs to duns. This is often the “feeding zone” that trout concentrate on. Ralph Cutter refers to this as the "killing zone". This is where having cripple imitations will be very effective. Feeding trout will often ignore nearby floating duns. You need to be aware of this multiple, masked hatch, and when this happens and have fly patterns to match emergers, duns, spinners in order to fish a Baetis complex hatch effectively.


The one saving grace of the Baetis complex is the way you can reduce their complexity by considering them all one group. They can be matched with color and size variations of the same set of flies. One problem is the broad spectrum of water types in which they live. You need to carry patterns that float on riffles, others that combine flotation with a fairly accurate silhouette to fish on nervous, uneasy water and finally you'll need flies that show the exact form of the insect on water so smooth that flotation is never a problem.

The Baetis complex hatch, or the tangle of hatches, is where the use of the "one precise right fly" just doesn't work. If you read John Gierach's book, Trout Bum, he has referred to fishing the BWO hatch as the "progression" of a blue wing olive hatch.

As the day goes along, you might begin by fishing a Baetis nymph pattern down deep along the bottom because you know there are lots of them down in their habitat. Then you'll switch to the same nymph fished shallow. You'll begin to notice duns and some trout will start feeding on them and you can be successful changing to a dry fly. But sometimes the trout will get finicky and you'll notice they're taking cripples, so you'll have to change to an emerger. And so forth, right through to the late afternoon spinner fall.

So what John Gierach has stated is that if you stick with one pattern through a blue winged olive hatch, you'll deal with some trout but probably end up frustrated. If instead, you observe the different stages of the hatch and how things change as the hatch progresses, and change patterns as the fish do, you'll continue to catch trout throughout the hatch. That's the goal.


So, pick up a new flybox, or recycle an old one, and label it BWOs. Fill it with patterns that match the size and color of the BWOs on your stream or river. Fill it with, nymphs, emergers, duns and spinners. Make sure you have dun patterns for (1) riffles (2) nervous water and (3) smooth water. If you do this you'll be ready for a Baetis complex hatch where ever you roam.

I will follow up this article with 4 additional articles with specific information on the habitat, flies, and techniques for presenting flies for the Baetis nymphs, emergers, duns and spinners

You can pick up Dave Hughes book, "Western Mayfly Hatches" at Amazon books by going to the following link. It is where most of this information came from.*&s=books&qid=1287687533&sr=1-1