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The Sulphurs are here!

Published by Joe Dziedzina [Dizzy] on 05/10/2021 (24744 reads)
The Sulphurs are here!
With the best hatch of the season fast approaching, I thought it might be helpful for some of the “Newbie’s” to post a few words on the Sulphur Hatch to get them off to a flying start this month… so if anyone has anything to add in the way of tips, tricks, details, etc. PLEASE feel free to chime in!

The months of May and June here in southeastern PA bring forth the greatest event of the fly-fishing season… the SULPHUR HATCH. These yellowish mayflies are actually made up of three (3) different mayfly species; Ephemerella rotunda, E. invaria, and E. dorothea. Most streams in SEPA hold all three (3) species which can be good AND bad. It’s good because it extends the sulphur hatch from 1st/2nd week of May through much of June (most seasons)… and it’s bad because there are subtleties that the fish notice and key on (sometimes) and if the angler does not adjust, he (or she) could be in for a long evening. The good news though, is that the “bad” is well within your control.

First a quick overview of the three (3) players, in order of emergence;
Ephemerella rotunda: Duns have a medium yellow body color with slight “olive cast” to them… the largest of the three by a hair, could be as large as a size 12 hook size, but a size 14 will do (a true “tweener”)… often hatch out of very swift water (just below riffles)… hatching usually begins around Mother’s Day and lasts 2-3 weeks… hatch most often in late afternoons (4-6 pm)

Ephemerella invaria: Duns have a yellowish/orange body color … best imitated with a size 14 hook… often hatch out of slightly slower flows than rotunda’s… hatching usually begins around 3rd week in May peaking around Memorial Day (slowing down in June)… hatch most often in early evenings (6-7 pm)

Ephemerella dorothea: Duns have a pale yellow body color … best imitated with a size 16 hook (sometimes 18)… often hatch out of slower pools… hatching usually begins in last week of May and lasting well into June… hatch most often in evenings (7-8:30 pm), sometimes right at dusk in a quick “blizzard” of activity.

Believe it or not, there are other “yellow” mayflies hatching during these same times as well, but those listed above make up the Sulphur Hatch as most anglers know it. As you can see there are differences between the three and it will save your sanity to have the proper sizes/colors to cover the gamut. At the very least I would carry size 14 dry fly’s in sulphur yellow to cover the rotunda/invaria and size 16 pale yellow imitations to cover the dorothea (some anglers use a Light Cahill for this). To compound the mayhem, in addition to the over-lapping hatch activity, trout will often key on a certain “stage” of emergence from drifting nymphs, to struggling emergers, to floating duns… and just when you think you have THAT all figured out, there could be spent spinners on the water as well!

If you show up to the stream in the mid afternoon and no fish are rising and no insects are on the water (or in the air)… you could be in for some fast action by tying on a Pheasant-tail nymph (size 14-16) and fishing the riffles and runs. Prior to emergence these nymphs will fill the water column as they struggle to reach the surface. Trout will be gorging on them and you will often see flashes in the stream as fish slash from side-to-side engulfing drifting nymphs by the mouthful.

Once a good supply of duns are on the surface the trout will come up for them and the real fun begins with dry flies… fish staging in faster water will be easier targets as they have precious little time to inspect your offering. Trout holding in slower pools will be a bit tougher, but may be larger and you should still dupe them easily with a stealthy “down & across” approach. If the fish refuse your floating dry, try tying an emerger pattern or weightless nymph about 6” off the back of the dry. This will take fish that are targeting these hapless naturals. Some of you may have heard people say that the trout are easier to catch at the beginning of the sulphur hatch but get smarter as the weeks wear on? These are the guys that don’t adjust to the dorothea activity and are missing out big time. The difference in a size 16 or 14 hook may not sound like much, but place the fly’s next to each other and you will see why the trout key on one or the other. Just pay attention to what is on the water and you’ll be OK.

The last piece of the puzzle is the spinnerfall. Again, this can be as frustrating or as rewarding as you want to make it. Personally I take my largest “dry fly caught” trout every season during the spinnerfall. It’s an easy meal and one that large trout rarely pass up. As you survey the stream take notice of the presence of any swarms of “dancing” mayflies over the riffles. These will be egg-laden females preparing to drop their cargo into the drink before dying and dropping in themselves. The males in all likelihood have already fallen, spent from mating activity. During sulphur season this activity most often takes place during the early evening if not right at dark (maybe early morning if air temp’s are too high for mating flights). These mating swarms start out high above the stream surface and if you happen to notice flocks of insect-eating birds (swallows, swifts, nighthawks… maybe bats) high above, you can be pretty sure that a spinnerfall is about an hour away. Sounds complicated but it is surprisingly simple… for this activity I carry just one fly—The Rusty Spinner—in sizes 14-18. Look for subtle risers, often times near the tail ends of pools, just “dimpling’ the surface and float your imitation right down into the waiting jaws of a heavy brown. If rising fish continue to ignore your floating dun, tie on a Rusty Spinner and 9 out of 10 times you will be surprised at the response.

Always keep in mind that ANY and ALL of the above described activities could be going on… sometimes simultaneously! Just be observant, let the trout tell you what they want, and you will enjoy your cigar and cold beverage a LOT more back at the parking area… this I promise.

*NOTE* The referenced taxon above is a bit outdated as the society of entomologists (or whoever they are) have decided that E. invaria and E. rotunda are now the same species (E. invaria)… also they have added a second dorothea to E. dorothea (E. dorothea dorothea). This info is strictly for the angler’s that are over-obsessed with details (like ME for example)… the trout still eat them the same as they always have.
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Author Thread
Published: 2009/5/20 13:00  Updated: 2009/5/20 13:00
Joined: 04/24/2009
From: South Jersey
Comments: 605
 Re: The Sulphurs are here!
Great information. Get out and fish this hatch!
Published: 2009/5/21 14:41  Updated: 2009/5/21 14:41
Joined: 05/21/2009
Comments: 4
 Re: The Sulphurs are here!
We gave a great Pale Sulphur hatch on the Clinch River in Eastern TN above Knoxville. I like yellow sally liqui lace plus one other nymph better then a PT. Now, the purist's will be on my case, but; nymph fishermen catch a lot of trout,too.
Published: 2009/5/22 0:39  Updated: 2009/5/22 0:39
Joined: 05/08/2009
Comments: 15
 Re: The Sulphurs are here!
Great article, but more pictures would have made it epic.
Published: 2010/5/18 15:16  Updated: 2010/5/18 15:16
Joined: 05/18/2010
From: Chester County
Comments: 4
 Re: The Sulphurs are here!
Great article and timely as well. I spent a couple hours on a favorite section of French Creek this past weekend watching a sporadic hatch of Sulphurs. When the trout began chasing the emergers I tied on a PT bead head in front of an Olive Emergent Sparkle Pupa (I did not have any Sulphur Emergers in my box) and the fun began. I caught a total of 9 trout in the next few minutes. The last two of the trout were caught on a small dry Sulphur. I couldn't stay very late so I imagine the hatch really got started after I left.
Published: 2014/5/13 2:10  Updated: 2014/5/13 2:10
Joined: 12/09/2012
From: Lewistown, PA
Comments: 74
 Re: The Sulphurs are here!
I've been fly fishing for like 3 years now, and have never once fished anything resembling a hatch. I always find myself going whenever I have time, which almost never corresponds with a hatch. This year though I'm absolutely making a point of fishing the sulphurs! I have a bunch of sulphur patterns tied up including comparaduns, hackle dry flies, emergers, nymphs, and rusty spinners. I really like the looks of the sulphur emerger pattern that was posted as a fly of the month a couple years ago. Here's the link: sulphur emerger
Published: 2014/5/13 14:21  Updated: 2014/5/13 14:21
Joined: 05/09/2013
From: Gibraltar PA
Comments: 24
 Re: The Sulphurs are here!
Got on a sulphur hatch last year on the upper reaches of the perkiomen here in Berks county. Never been in the middle of anything like it before in my life. The water looked like it was literally boiling with all the topwater action. Some of the most fun flyfishing I've had so far for sure.
Published: 2014/5/19 15:32  Updated: 2014/5/19 15:32
Joined: 01/31/2008
From: Lebanon, PA, via everywhere
Comments: 2598
 Re: The Sulphurs are here!
Great article!

From a fishermen's perspective, it's fine to leave rotunda and invaria separate because it highlights the range within this species. But as a technical correction, entomologists have now determined that they are in fact the same species. The sulphers are down to 2, and rotunda was left out of the mix. Invaria range in color from olive to brown to yellow, in sizes ranging from 12-16, and inhabit generally medium current areas. The spinners are generally "rusty" colored, but more grayish red than say, March Browns. The dorothea's are indeed smaller, inhabit slower water, start a week or two later (but overlap), and a pale yellow or white as duns and also paler as spinners, sometimes with a yellowish orange tinge.

It is somewhat important to distinguish between the above "sulphers" and the other yellow mayflies. Hatching behavior is very different. The above sulphers do swim to the surface as nymphs, and emerge from their shucks on the surface. This makes emerger patterns extra important, and brings floating nymphs, trailing shuck patterns, and the like into the equation. The cahills of the maccaffertium genus, on the other hand, are clinger nymphs and thus emerge primarily in or near heavy riffs. They crawl along the bottom to slow, shallow water (usually edges) before emergence. So you fish them in different areas, with different tactics. Epeorus vitreus (pink lady) is yet another clinger, which emerges on the bottom and "flies" to the surface as a dun. This makes floating nymphs unimportant, but swung soft hackles very effective.

True sulphers have 3 tails, not 2. If the hatching bug doesn't have 3, focus more on riffs, because it's a cahill or a pink lady, not a sulpher.
Published: 2016/5/2 11:17  Updated: 2016/5/2 11:17
Joined: 10/24/2012
From: Landenberg, PA
Comments: 454
 Re: The Sulphurs are here!
nice article.

are the sulphur dries tied on 2x long hooks ?

when I was on the Delaware last May there were big yellow mayflies about 15mm long, and I wondered if they were Sulphurs or were they Cahills ?

I'd bought some #16 and #14 sulphurs online, buy they were tiny compared to what was on the water...
Published: 2016/5/14 17:52  Updated: 2016/5/14 17:52
Joined: 09/02/2014
Comments: 382
 Re: The Sulphurs are here!
Really informative piece. I fished the Little J 2 weekends ago, and your one comment hit the nail on the head for me. Sulphurs were coming off hard from about noon on. My friend caught half a dozen, while I managed only 1. Trout would rise to my fly but when I would go to set the hook, there was no trout. They were basically rising then refusing my fly at the last moment. My friend and I compared the sulphurs we had tied for the trip. My dubbing was pale yellow on all my ties, while my friend had mixed in a bit of orange to his yellow dubbing.

Lesson learned. I guess we all learn something new every trip we take out on the water

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