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The Mayfly

Published: 16th May 2022 | Author: Paul Procter

It’s that time of year again… “Duffers Fortnight” when reputedly, trout throw caution to the wind and fishermen cash in on their gluttony. Late May and early June sees the emergence of our largest and most spectacular ephemerid – the Mayfly. 

Over the coming weeks, stillwaters and rivers will host the season’s high point as we look to connect with this celebrated hatch. To both the newcomer and seasoned angler alike, the mere word “Mayfly” summons up extraordinary emotions. The sight of the season’s first adult mayfly is enough to make experienced anglers go weak at the knees. Surely, with many years fishing under our belts, one would become accustomed to the presence of these large unmistakable flies?  If anything, the complete opposite rings true!  The more mayflies you see, the more captivated you become by this enchanting ephemerid.  As newly emerged duns drift past, with fumbling fingers, you franticly tackle up.  A scenario I suspect we’re all familiar with.    

Three Species

There are three species of mayfly throughout the UK, Ephemera Danica, Ephemera Vulgata and Ephemera Lineata.  As E Lineata is somewhat scarce (to my knowledge, I’ve never come across this species), we will be referring to the more widespread E. Danica and E. Vulgata.  Generally speaking, Ephemera Danica is the largest, with a more olive-yellowy hue in the dun stage. E. Vulgata tends to be much darker and can appear almost black in colour, especially at distance.  Do remember that the female of both species is slightly larger than the male.  Males can be identified by their larger eyes and a pair of claspers situated on the penultimate abdominal segment, nearest the tail. Across the pond, I believe America has a similar upwing, commonly labelled the “Green Drake”.

Where Can You Find Them?

It’s widely accepted that mayfly thrive in more calcareous waters.  Enriched by chalk and limestone, such waters provide the ideal habitat.  And whilst often linked with the fertile chalkstreams of the South, mayfly are well established on a range of water types the length and breadth of the UK.  Indeed the great Irish Loughs boast mayfly in good numbers, as do many Scottish Lochs.  Equally, they can be found on our small stillwaters where day ticket visitors can tap into exciting sport.  Surprisingly, mayfly pop-up on more upland waters too.  The many headwaters I fish contain them, though admittedly, not in the hordes you find lower down a river system.  In my home county, Ullswater is a particular favourite where I fully expect to find mayfly during late spring.

The Nymphs

Preferring a silty or fine gravel substrate, mayfly nymphs reside in burrows.  These nymphs attain quite a size as many measure more than an inch long when approaching maturity.  Prior to hatching, like other upwinged nymphs their wing buds darker considerably.  With a long, sinuous body, three tails and feathery gills lining their abdomens mayfly nymphs are quite distinctive.  As ever, coloration depends on location though overall nymphs wear a creamy-yellow coat. If there’s still any doubt then dark brown markings on the upper abdomen are a dead giveaway and are most conspicuous on the three abdominal segments nearest the tail.

Mature mayfly nymphs attain an inch in length and have a sinuous swimming motion.

As the critical hatch period approaches, nymphs become restless and are thought to make dummy runs.  Vulnerable now, this helps explain why mayfly nymphs turn up in trout way before the season’s first dun is ever seen.  I’ve certainly come across this on many occasions.  As you can image, with such elongated bodies, nymphs ascend with a vertical undulating action, giving us license to impart movement when we’re fishing the nymph.

The Emergers

Once at the surface the nymphal shuck splits down a predetermined line.  The actual emerging process takes but seconds.  However, depending on atmospheric conditions and surface tension, newly emerged duns (sub imago) may remain on the surface for up to a few minutes as their faculties develop. At this stage and during their maiden flight they’re rendered defenceless as trout, swallows and gulls home in on ungainly duns.

Emerging duns often remained fastened to their shucks, making them easy pickings for trout

Mayfly that do make it to safety seek out the underside of board leafed trees before transforming into adult spinners (imago).  Sexually mature now, male adult spinners gather to perform their mating dance in a bid to attract nearby females.  This tends to take place during calmer conditions and towards evening time.  With mating complete female spinners return to the water to deposit their eggs for the next generation.  Mission accomplished spent spinners litter the water surface, providing another feeding opportunity for trout.  Indeed, whilst spinner falls are notoriously difficult to predict, under the right conditions, so intense can be the spinner falls that this activity can overshadow daytime hatches. 

The Mayfly dun (sub imago) is easily distinguished by those dusky forewings and tail filaments approximately the length of their body.
Mayfly spinners (imago) can be separated from duns by their long forelegs, clear, veined wings and extremely long tails. 

Arriving at the water, my first port of call is the underside of any waterside canopy.  Then I make a point of checking the windward (exposed) bank if on stillwaters, or the foamy margin when fishing rivers.  It’s here you’re likely to find the discarded shucks, or casualties from earlier hatches.  Hopefully, there’ll be some promising signs with the odd mayfly present.  On occasions I’ve found masses of mayfly spinners awash in the margins.  Obviously this points to significant spinner action the previous evening, which helps when planning your day.  It goes without saying, make a point of staying until dusk now!

Spent spinners stacked up in the margins are sign that thinks have been in full swing. 

Fishing The Nymph

Obviously, our minds are full of dry fly sport, however, when nothing stirs, it’s best to fish a nymph.  On stillwaters I normally fish two of Procter’s Active Mayfly Nymphs on a 16ft leader, positioned 6ft apart.  Cast out and let the flies settle before imparting a steady figure-of-eight retrieve.  As natural nymphs have an impressive turn of speed, remember to mix up the retrieve.  Steady foot long draws intermittent with plenty of pauses are a favourite.

Procter’s Active Mayfly Nymph

On rivers a single nymph on a 12ft Fulling Mill Masterclass 12ft 4X tapered leader works best.  This should be cast into likely water and fished back on a slightly tensioned line so takes can be detected. I achieve this be gently raising the rod in tempo with the current to guide my nymph back rather than strip in line as this way at the end of your dry there’s adequate fly line outside the rod tip to roll cast your fly back into the honey hole in one swift movement. 

Fishing Surface Flies

Once mayfly start emerger proper, we can look to surface flies for sport. Initially, due to their sheer size, mayfly can be intimidating to trout and they sometimes struggle to intercept them.  This is where an emerger pattern scores well, as with it’s best part hanging subsurface, fish can latch on easily now.  With its mobile marabou body the Procter’s Active Mayfly Emerger takes some beating. And, the Procter’s Stuck Shuck Compara Mayfly is another favourite when trout seem a little shy.

Tippet and Leader

Eventually, trout will become accustomed to adult mayflies and switch to them as duns ride the surface, waiting for their wings to harden.  Whether it’s lake, or river, a single dry fly is much easier to handle when constantly targeting rising fish. Although I generally advocate fine diameter tippets to promote more natural movement of imitations, when it comes to big flies, leader set-up require some thought.

Casting such huge creations on fine tippets is courting disaster.  Sure, you can just about get away with it at close range, but try pitching a large fly into a brisk wind.  Not only will the leader collapse, resulting in the fly falling short there’s a risk of leaders twisting too, as large hackled flies are prone to spinning during fishing. In no time they’ll snarl kink delicate tippets.  Strong, robust and stout the Fulling Mill masterclass copolymer in 4x (6.65lb) is up to the job.  It has both sufficient strength to deal with larger trout and an adequate diameter of 0.187mm to turn over bushy flies.


I usually preach presenting a static fly when it comes to dry fly fishing and you won’t go far wrong with a Procters Active Mayfly Dun.  That said, movement can become a prime trigger at mayfly time.  If you care to study both adult duns and spinners they often kick and contort themselves when on water.  We can copy this be gently tweaking our line, or gently wiggling the rod tip to make our fly judder.  This is especially true as the light fades and trout lock onto spinners.

Procter’s Active Mayfly Dun

Talking of which, aside from enjoying a hatch during the day, come evening time we can expect female mayfly spinners to return and egg lay over open water.  Such is the bean feast now that spinner falls reputedly attracting some of the larger trout to the surface! Now the Procter’s Twinkle Wing Spinner tends to sort out better fish.

The Mayfly is one of the most anticipated times of the year. Learn from the best as Paul Procter shares his tips for fishing it effectively!
Procter’s Twinkle Wing Spinner

It’s wise now to crouch low, so you’re looking across the surface rather than into it.  This makes spotting rise forms and your fly so much easier.  As trout tend to become bolder in the growing darkness, you can wait a fraction longer before tightening into any fish that show interest.  Lift too soon and you’ll almost certainly pull the fly right out of a trout’s mouth.  I’ve even been known to wait until the leader/tip of line stabs away until I strike.  Such tactics might sound foolhardy, but big trout mopping up dead spinners often feed with bewildering confidence that verges on arrogance!

Mayfly time has the reputation of producing some thumping trout like this stunner taken during a hatch.
Chalkstreams provide us with first class mayfly fishing in late spring

To read more from Paul, check out his recent Q&A!

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